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Sample records for quantifying trace amounts

  1. Uncertainties in measuring trace amounts of cobalt and europium with low-flux neutron activation analysis

    Directory of Open Access Journals (Sweden)

    Burnham Steven

    2017-01-01

    Full Text Available Neutron activation analysis is widely used for identification of elements and their quantities even in trace amounts in the samples of almost any type. The challenges in detecting trace amounts of particular elements are often associated with the neutron flux produced at the research reactors. Low-flux neutron activation analysis usually presents the biggest challenge when analyzing trace quantities of elements with lower magnitude of radiative capture cross-sections. In this paper, we present the methodology and the quantified uncertainties associated with the detection of trace amounts of cobalt and europium, using as an example concrete aggregates. Recent growing interest is in improving structural concrete (increasing its strength but reducing its activation in nuclear power plant environments. Aside from buildings, structural concrete is also used as a biological shield in nuclear power plant that become radioactive after exposure to neutron flux. Due to radiative capture interactions, artificial radionuclides are generated to high enough concentrations that classify concrete as low-level radioactive waste at the time of the plant's decommissioning. Disposal of this concrete adds to the expense of nuclear power plant financing and its construction. Three radionuclides, 60Co, 152Eu, and 154Eu, account for 99 % of total residual radioactivity of nuclear power plant decommissioned concrete. IAEA document RS-G-1.7, Application of the Concepts of Exclusion, Exemption, and Clearance, specifies clearance levels of radionuclides specific activities: a specific activity lower than 0.1 Bqg-1 for 60Co and 152Eu, and 154Eu allows for a concrete to be recycled after decommissioning of the nuclear power plant. Therefore, low-flux neutron activation analysis is used to test the detection limits of trace elements in samples of cement, coarse, and fine concrete aggregates. These samples are irradiated at the University of Utah's 100 kW TRIGA Reactor at

  2. Trace amounts of copper induce neurotoxicity in the cholesterol-fed mice through apoptosis.

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    Lu, Jun; Zheng, Yuan-Lin; Wu, Dong-Mei; Sun, Dong-Xu; Shan, Qun; Fan, Shao-Hua

    2006-12-11

    Evidence has been gathered to suggest that trace amounts of copper induce neurotoxicity by interaction with elevated cholesterol in diet. Copper treatment alone showed no significant learning and memory impairments in behavioral tasks. However, copper-induced neurotoxicity was significantly increased in mice given elevated-cholesterol diet. Trace amounts of copper decreased the activity of SOD and increased the level of malondialdehyde (MDA) in the brain of cholesterol-fed mouse. Copper also caused an increase in amyloid precursor protein (APP) mRNA level and the activation of caspase-3 in the brain of cholesterol-fed mice. The apoptosis-induced nuclear DNA fragmentation was detected in the brain of those mice by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end-labeling staining. These findings suggest that trace amounts of copper induce neurotoxicity in cholesterol-fed mice through apoptosis caused by oxidative stress.

  3. Distribution and accumulation of trace amounts in forest ecosystems. Verteilung und Akkumulation von Spurenstoffen in Waldoekosystemen

    Energy Technology Data Exchange (ETDEWEB)

    Lamersdorf, N.

    1988-01-01

    The work focuses on the comparison of the contents in trace amounts of individual compartments (needles, the bark of branches and stem, stem wood, different root fractions, organic ground cover, mineral soil) of three spruce forest ecosystems. Moreover a comparison of sites was made by examining spot samples from a spruce forest ecosystem (needles, bark), a beech forest ecosystem (bark, wood), and two forest stands of different leaf trees (beech, English oak; organic ground covers). The following elements were examined in varying intensities in the groups of samples: As, Bi, Pb, Cd, Se, Tl, Cr, Co, Cu, Mn, Ni, Zn, Sb, Be, Hg, Fe, Mo and V. The analytical effort involved depended for one thing on the wish to complete available knowledge on the distribution of trace amounts in forest ecosystems, and for the other on the desire to verify by means of a damaged spruce stand, whether the accumulation or depletion of trace amounts are in part responsible for forest disease in the north-west German coastal region. In parallel to these investigations, available data regarding the bills for main substances and trace amounts from other research projects were made use of. As a basis for characterizing and judging the trace substance concentrations ascertained in the forest ecosystems, the book gives an overview of the state of knowledge in the form of a bibliography.

  4. Quantifying the digital traces of Hurricane Sandy on Flickr.

    Science.gov (United States)

    Preis, Tobias; Moat, Helen Susannah; Bishop, Steven R; Treleaven, Philip; Stanley, H Eugene

    2013-11-05

    Society's increasing interactions with technology are creating extensive "digital traces" of our collective human behavior. These new data sources are fuelling the rapid development of the new field of computational social science. To investigate user attention to the Hurricane Sandy disaster in 2012, we analyze data from Flickr, a popular website for sharing personal photographs. In this case study, we find that the number of photos taken and subsequently uploaded to Flickr with titles, descriptions or tags related to Hurricane Sandy bears a striking correlation to the atmospheric pressure in the US state New Jersey during this period. Appropriate leverage of such information could be useful to policy makers and others charged with emergency crisis management.

  5. Separation and preconcentration trace amounts of gold by using modified organo nanoclay closite 15A

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    Sayed Zia Mohammadi

    2010-01-01

    Full Text Available The application of organo nanoclay 5-(4-dimethylamino-benzylidene rhodanine-immobilized as a new, easily prepared, and stable solid sorbent for preconcentration trace amounts of Au(III ions in aqueous solution is presented. The sorption of Au(III ions was quantitative in the pH range of 2-4, and quantitative desorption occurred instantaneously with 10.0 mL of a mixture containing 0.5 mol L-1 Na2S2O3 and KSCN. Various parameters, such as the effect of pH, breakthrough volume, extraction time, and interference of a large number of anions and cations have been studied. The proposed method has been applied for determination of trace amount of gold in water samples.

  6. Weighted fourier series representation and its application to quantifying the amount of gray matter.

    Science.gov (United States)

    Chung, Moo K; Dalton, Kim M; Shen, Li; Evans, Alan C; Davidson, Richard J

    2007-04-01

    We present a novel weighted Fourier series (WFS) representation for cortical surfaces. The WFS representation is a data smoothing technique that provides the explicit smooth functional estimation of unknown cortical boundary as a linear combination of basis functions. The basic properties of the representation are investigated in connection with a self-adjoint partial differential equation and the traditional spherical harmonic (SPHARM) representation. To reduce steep computational requirements, a new iterative residual fitting (IRF) algorithm is developed. Its computational and numerical implementation issues are discussed in detail. The computer codes are also available at http://www.stat.wisc.edu/-mchung/softwares/weighted.SPHARM/weighted-SPHARM.html. As an illustration, the WFS is applied i n quantifying the amount ofgray matter in a group of high functioning autistic subjects. Within the WFS framework, cortical thickness and gray matter density are computed and compared.

  7. Tracing and quantifying groundwater inflow into lakes using radon-222

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    T. Kluge

    2007-06-01

    Full Text Available Due to its high activities in groundwater, the radionuclide 222Rn is a sensitive natural tracer to detect and quantify groundwater inflow into lakes, provided the comparatively low activities in the lakes can be measured accurately. Here we present a simple method for radon measurements in the low-level range down to 3 Bq m−3, appropriate for groundwater-influenced lakes, together with a concept to derive inflow rates from the radon budget in lakes. The analytical method is based on a commercially available radon detector and combines the advantages of established procedures with regard to efficient sampling and sensitive analysis. Large volume (12 l water samples are taken in the field and analyzed in the laboratory by equilibration with a closed air loop and alpha spectrometry of radon in the gas phase. After successful laboratory tests, the method has been applied to a small dredging lake without surface in- or outflow in order to estimate the groundwater contribution to the hydrological budget. The inflow rate calculated from a 222Rn balance for the lake is around 530 m3 per day, which is comparable to the results of previous studies. In addition to the inflow rate, the vertical and horizontal radon distribution in the lake provides information on the spatial distribution of groundwater inflow to the lake. The simple measurement and sampling technique encourages further use of radon to examine groundwater-lake interaction.

  8. Simultaneous Determination of Large Amount of Uranium and Trace Fission Elements by DRC-ICP-MS

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Lei; LI; Hui-bo; LIU; Fang; HE; Hui; CONG; Hai-feng

    2013-01-01

    Large amount of uranium and trace fission product elements are widely exist in reprocessing process.Since the difference of elements concentration,chemical separation and various dilution ratios should be used to obtain all the values.Inductively coupled plasma mass spectrometry(ICP-MS)can be used to determination of more than 75%elements in the periodic table and meet the needs for analysis of fission

  9. Determination of Trace Amount of Yttrium with Bromopyrogallol Red by Solid-phase Spectrophotometry

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A simple and sensitive method for the determination of trace amount of yttrium by solid-phase spectrophotometry has been studied. Yttrium can form a 1∶1 complex with bromopyrogallol red (BPR) on resin, which was determined directly at 605 nm, pH=6.5. It has a highly sensitivity ( = 6.3€?06) which is 300-fold higher than the corresponding spectrophotometry in solution. The method was applied to the determination of yttrium in churchite.

  10. Steam stable mesoporous silica MCM-41 stabilized by trace amounts of Al.

    Science.gov (United States)

    Tompkins, Jordan T; Mokaya, Robert

    2014-02-12

    Evaluation of low and ultralow Al content (Si/Al between 50 and 412) aluminosilicate Al-MCM-41 materials synthesized via three contrasting alumination routes, namely, direct mixed-gel synthesis, post-synthesis wet grafting, and post-synthesis dry grafting, indicates that trace amounts of Al introduced via dry grafting can stabilize mesoporous silica MCM-41 to steaming at 900 °C for 4 h. It was found that trace amounts of Al (Si/Al > 400) introduced via so-called dry grafting of Al stabilize the virtually purely siliceous MCM-41 to steaming, whereas Al incorporated via other methods that involve aqueous media such as direct mixed gel synthesis or wet grafting of Al offer only limited protection at low Al content. It is particularly remarkable that a post-synthesis dry grafted Al-MCM-41 material possessing trace amounts of Al (i.e., Si/Al ratio of 412) and surface area and pore volume of 1112 m(2)/g and 1.20 cm(3)/g, respectively, retains 90% (998 m(2)/g) of the surface area and 85% (1.03 cm(3)/g) of the pore volume after exposure to steaming at 900 °C for 4 h. Under similar steam treatment conditions, the mesostructure of pure silica Si-MCM-41 is virtually destroyed and undergoes a 93% reduction in surface area (958 m(2)/g to 69 m(2)/g) and 88% decrease in pore volume (0.97 cm(3)/g to 0.12 cm(3)/g). The steam stable ultralow (i.e., trace) Al containing MCM-41 materials is found to be virtually similar to mesoporous pure silica Si-MCM-41 with hardly any detectable acidity. The improvement in steam stability arises from not only the presence of trace amounts of Al, but also from an apparent increase in the level of silica condensation that is specific to dry grafted alluminosilicate MCM-41 materials. The more highly condensed framework has fewer silanol groups and therefore is more resistant to hydrolysis under steaming conditions.

  11. SU-E-P-31: Quantifying the Amount of Missing Tissue in a Digital Breast Tomosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Goodenough, D [George Washington University, Washington, DC (United States); Olafsdottir, H; Olafsson, I; Fredriksson, J; Kristinsson, S; Oskarsdottir, G; Kristbjornsson, A [Raforninn Ehf., Reykjavik, Gullbringusysla (Iceland); Mallozzi, R; Healy, A; Levy, J [The Phantom Laboratory, Salem, NY (United States)

    2015-06-15

    Purpose: To automatically quantify the amount of missing tissue in a digital breast tomosynthesis system using four stair-stepped chest wall missing tissue gauges in the Tomophan™ from the Phantom Laboratory and image processing from Image Owl. Methods: The Tomophan™ phantom incorporates four stair-stepped missing tissue gauges by the chest wall, allowing measurement of missing chest wall in two different locations along the chest wall at two different heights. Each of the four gauges has 12 steps in 0.5 mm increments rising from the chest wall. An image processing algorithm was developed by Image Owl that first finds the two slices containing the steps then finds the signal through the highest step in all four gauges. Using the signal drop at the beginning of each gauge the distance to the end of the image gives the length of the missing tissue gauge in millimeters. Results: The Tomophan™ was imaged in digital breast tomosynthesis (DBT) systems from various vendors resulting in 46 cases used for testing. The results showed that on average 1.9 mm of 6 mm of the gauges are visible. A small focus group was asked to count the number of visible steps for each case which resulted in a good agreement between observer counts and computed data. Conclusion: First, the results indicate that the amount of missing chest wall can differ between vendors. Secondly it was shown that an automated method to estimate the amount of missing chest wall gauges agreed well with observer assessments. This finding indicates that consistency testing may be simplified using the Tomophan™ phantom and analysis by an automated image processing named Tomo QA. In general the reason for missing chest wall may be due to a function of the beam profile at the chest wall as DBT projects through the angular sampling. Research supported by Image Owl, Inc., The Phantom Laboratory, Inc. and Raforninn ehf; Mallozzi and Healy employed by The Phantom Laboratory, Inc.; Goodenough is a consultant to The

  12. A sensitive fluorimetric method for determination of trace amounts of nitrite based on luminescence energy transfer

    Energy Technology Data Exchange (ETDEWEB)

    Wang Lun, E-mail: wanglun@mail.ahnu.edu.c [Anhui Key Laboratory of Chemo-Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000 (China); Chen Jingguo; Chen Hongqi; Zhou Cailing; Ling Bo; Fu Jie [Anhui Key Laboratory of Chemo-Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000 (China)

    2011-01-15

    An efficient luminescence energy transfer (LET) system based on terbium(III)-sodium hexametaphosphate (Tb/SHMP) chelates as donor and 4-((4-(2-aminoethylamino)naphthalen-1-yl)diazenyl)benzenesulfonic acid dihydrochloride (ANDBS) as acceptor was developed for sensitive determination of trace nitrite. Stable and strong fluorescence Tb/SHMP chelates were prepared in aqueous solution. Based on Griess Reaction, ANDBS was generated by the quantitative reaction of nitrite, sulfanilamide and N-(1-naphtyl)-ethylenediamine dihydrochloride (N1NED). The degree of the overlap was effective for LET between the emission spectrum of Tb/SHMP chelates and the absorption spectrum of ANDBS. Based on the luminescence intensity quenching of Tb/SHMP chelates in proportion to the trace amounts of nitrite, a new assay for the selective and sensitive determination of nitrite was developed. Under the optimum conditions, the linear calibration graph was obtained with a linear range of 0.00040-0.20 {mu}g mL{sup -1} (R=0.99657). The detection limit of NO{sub 2}{sup -} was 0.00010 {mu}g mL{sup -1} (R=0.99657). The method was applied successfully to the determination of nitrite for synthetic samples.

  13. Real-time immuno-PCR: an approach for detection of trace amounts of transgenic proteins.

    Science.gov (United States)

    Kumar, Rajesh; Sinha, Rajeshwar P

    2014-01-01

    The research on manipulation of crop genomes for transgenic development is continuously increasing due to several benefits. The major concerns linked to the effect of transgenic crops are human health and environment sustainability. To monitor transgenic samples in the food chain, several highly sensitive and specific DNA-based and protein-based detection methods are being used. However, real- time immunio-PCR (RT-IPCR) assay would be able to provide a sensitive detection of trace amounts of transgenic proteins or allergens in the samples and help in monitoring these materials. In the present study, we developed a novel RT-IPCR method to monitor CrylAc transgenic protein in samples with an LOD of 100 pg/mL. The assay may also be useful in the evaluation of functional stability of transgenes inserted in the plant genome.

  14. Electrochemical Impedance Sensors for Monitoring Trace Amounts of NO3 in Selected Growing Media

    Directory of Open Access Journals (Sweden)

    Seyed Alireza Ghaffari

    2015-07-01

    Full Text Available With the advent of smart cities and big data, precision agriculture allows the feeding of sensor data into online databases for continuous crop monitoring, production optimization, and data storage. This paper describes a low-cost, compact, and scalable nitrate sensor based on electrochemical impedance spectroscopy for monitoring trace amounts of NO3− in selected growing media. The nitrate sensor can be integrated to conventional microelectronics to perform online nitrate sensing continuously over a wide concentration range from 0.1 ppm to 100 ppm, with a response time of about 1 min, and feed data into a database for storage and analysis. The paper describes the structural design, the Nyquist impedance response, the measurement sensitivity and accuracy, and the field testing of the nitrate sensor performed within tree nursery settings under ISO/IEC 17025 certifications.

  15. Electrochemical Impedance Sensors for Monitoring Trace Amounts of NO3 in Selected Growing Media

    Science.gov (United States)

    Ghaffari, Seyed Alireza; Caron, William-O.; Loubier, Mathilde; Normandeau, Charles-O.; Viens, Jeff; Lamhamedi, Mohammed S.; Gosselin, Benoit; Messaddeq, Younes

    2015-01-01

    With the advent of smart cities and big data, precision agriculture allows the feeding of sensor data into online databases for continuous crop monitoring, production optimization, and data storage. This paper describes a low-cost, compact, and scalable nitrate sensor based on electrochemical impedance spectroscopy for monitoring trace amounts of NO3− in selected growing media. The nitrate sensor can be integrated to conventional microelectronics to perform online nitrate sensing continuously over a wide concentration range from 0.1 ppm to 100 ppm, with a response time of about 1 min, and feed data into a database for storage and analysis. The paper describes the structural design, the Nyquist impedance response, the measurement sensitivity and accuracy, and the field testing of the nitrate sensor performed within tree nursery settings under ISO/IEC 17025 certifications. PMID:26197322

  16. Study of Atmospheric Trace Gas Amounts at the Stara Zagora Ground-Based Station

    Science.gov (United States)

    Werner, R.; Valev, D.; Kostadinov, I.; Atanassov, At.; Giovanelli, G.; Petritoli, A.; Bortoli, D.; Ravegnani, F.

    2006-03-01

    Since the end of August 1999 twilight daily measurements of scattered zenith sky radiation have been carried out at Stara Zagora for determination of trace gas amounts, deploying GASCOD instrument. It was developed at the Institute of Atmospheric Science and Climate, Bologna. Reference spectra are obtained at midday. The instrument, appearing a UV-VIS spectrometer, registers the zenith sky spectra automatically and 410 nm to 460 nm spectral interval is used to retrieve NO2 and O3 slant column amounts (SCA) by application of the DOAS methodology. The spectral analysis uses minimum least squares fitting of the cross sections at the expected absorbers to a logarithm of the twilight spectrum and a reference spectrum. The accumulated time series show the well-known typical seasonal variations, caused by the solar insulation. The residual time series of the removed semi-annual seasonal cycles from the measured original series show many different variations, with short periods up to inter-annual variations. Single spikes of SCA are detected and we consider them a result of over-passing weather fronts and/or lightning. Variations of SCA with time scale up to about 10 days are the consequence of weather cyclones. Some short-term variations of NO2 and O3 SCA are a result of intensive stratospheric-tropospheric exchange. Other residual time series periods are caused by Rossby waves, by over-passing of the polar vortex filaments. The inter-annual variations can be affected by QBO and NAO. Applying wavelet analysis of the obtained NO2 slant column amount data series, and the total O3 amount obtained by the GOME instrument, during the 23-rd solar cycle maximum, time intervals are found with periods of 27 days on the time scale. The applied cross-correlation analysis demonstrates a phase lag of some days of the NO2 and O3 response to the 27-days solar cycle. The calculated vertical column amounts of NO2 are used for validation of the satellite measurements, e.g. SCIAMACHY NO2

  17. Titration of uranium trace amounts in waters environment; Dosage de traces d'uranium(VI) dans des eaux d'environnement

    Energy Technology Data Exchange (ETDEWEB)

    Larabi-Gruet, N.; Ithurbide, A.; Poulesquen, A.; Beaucaire, C. [CEA Saclay, Dept. de Physico-Chimie (DEN/DANS/DPC/SECR/L3MR), 91 - Gif sur Yvette (France); Peulon, S.; Chausse, A. [Univ. d' Evry-val-d' Essonne, Laboratoire Analyse et Modelisation pour la Biologie et l' Environnement (CNRS-CEA-Univ. d' Evry UMR 8587), 91 - Evry (France)

    2007-07-01

    In the framework of studies concerning the uranium migration in soils and rocks, it seems necessary to quantify the uranium(VI) dissolved in solution. In the environmental conditions, the uranium(VI) is present at trace amounts. The most adapted method to this study and easy to carry out is the Adsorptive Stripping Voltammetry. By addition of a compound (ligand) with a reducing and strong complexing power, the uranium(VI) present in solution is reduced into a U(VI)-ligand complex. This specie is then oxidized and adsorbed on the mercury droplet where an electrolytic pre-concentration of the element to determine the quantity of is carried out. At last, a cathodic re-dissolution of the specie adsorbed in the U(IV)-ligand complex is carried out. The chosen analytical method is the differential impulsional voltammetry. With this method, it is possible to quantify low electro-active species quantities (sensitivity {approx}25 ppt (10{sup -10} mol.L{sup -1}) for the uranium). This titration method in solution has been optimized, at first, in a non complexing medium. Then, the uranium in solution has been titrated in media whose composition has been progressively complexed (additions of CO{sub 3}{sup 2-}, SO{sub 4}{sup 2-}, Cl{sup -}..) for being at last representative of the environmental interstitial waters. At last, this study has been carried out too by ICP-MS (Inductively Coupled Plasma-Mass Spectrometry) in order to compare the analysis sensitivity of these two detection methods. (O.M.)

  18. Grating light reflection spectroelectrochemistry for detection of trace amounts of aromatic hydrocarbons in water

    Energy Technology Data Exchange (ETDEWEB)

    KELLY,MICHAEL J.; SWEATT,WILLIAM C.; KEMME,SHANALYN A.; KASUNIC,K.J.; BLAIR,DIANNA S.; ZAIDI,S.H.; MCNEIL,J.R.; BURGESS,L.W.; BRODSKY,A.M.; SMITH,S.A.

    2000-04-01

    Grating light reflection spectroscopy (GLRS) is an emerging technique for spectroscopic analysis and sensing. A transmission diffraction grating is placed in contact with the sample to be analyzed, and an incident light beam is directed onto the grating. At certain angles of incidence, some of the diffracted orders are transformed from traveling waves to evanescent waves. This occurs at a specific wavelength that is a function of the grating period and the complex index of refraction of the sample. The intensities of diffracted orders are also dependent on the sample's complex index of refraction. The authors describe the use of GLRS, in combination with electrochemical modulation of the grating, for the detection of trace amounts of aromatic hydrocarbons. The diffraction grating consisted of chromium lines on a fused silica substrate. The depth of the grating lines was 1 {micro}m, the grating period was 1 {micro}m, and the duty cycle was 50%. Since chromium was not suitable for electrochemical modulation of the analyte concentration, a 200 nm gold layer was deposited over the entire grating. This gold layer slightly degraded the transmission of the grating, but provided satisfactory optical transparency for the spectroelectrochemical experiments. The grating was configured as the working electrode in an electrochemical cell containing water plus trace amounts of the aromatic hydrocarbon analytes. The grating was then electrochemically modulated via cyclic voltammetry waveforms, and the normalized intensity of the zero order reflection was simultaneously measured. The authors discuss the lower limits of detection (LLD) for two analytes, 7-dimethylamino-1,2-benzophenoxazine (Meldola's Blue dye) and 2,4,6-trinitrotoluene (TNT), probed with an incident HeNe laser beam ({lambda} = 543.5 nm) at an incident angle of 52.5{degree}. The LLD for 7-dimethylamino-1,2-benzophenoxazine is approximately 50 parts per billion (ppb), while the LLD for TNT is approximately

  19. Ligandless-dispersive liquid-liquid microextraction of trace amount of copper ions

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadi, Sayed Zia, E-mail: szmohammadi@yahoo.com [Department of Chemistry, Payame Noor University (PNU), Kerman (Iran, Islamic Republic of); Afzali, Daryoush [Environment Department, Institute Research of Environmental Sciences, International Center for Science, High Technology and Environmental Sciences, Kerman (Iran, Islamic Republic of); Baghelani, Yar Mohammad [Department of Chemistry, Payame Noor University (PNU), Kerman (Iran, Islamic Republic of)

    2009-10-27

    In the present work, a new ligandless-dispersive liquid-liquid microextraction (LL-DLLME) method has been developed for preconcentration trace amounts of copper as a prior step to its determination by flame atomic absorption spectrometry. In the proposed approach 1,2-dicholorobenzene and ethanol were used as extraction and dispersive solvents, respectively. Some factors influencing on the extraction efficiency of copper and its subsequent determination were studied and optimized, such as the extraction and dispersive solvent type and volume, pH of sample solution, extraction time and salting out effect. Under the optimal conditions, the calibration curve was linear in the range of 1.0 ng mL{sup -1}-0.6 {mu}g mL{sup -1} of copper with R{sup 2} = 0.9985. Detection limit was 0.5 ng mL{sup -1} in original solution (3S{sub b}/m) and the relative standard deviation for seven replicate determination of 0.2 {mu}g mL{sup -1} copper was {+-}1.4%. The proposed method has been applied for determination of copper in standard and water samples with satisfactory results.

  20. Determination of trace amounts of thallium by adsorptive cathodic stripping voltammetry with xylenol orange.

    Science.gov (United States)

    Shams, Esmaeil; Yekehtaz, Mehdi

    2002-09-01

    Trace amounts of thallium(I) can be determined using adsorptive cathodic stripping voltammetry in the presence of Xylenol Orange (XO). The reduction current of the thallium(I)-XO complex ion was measured by square-wave cathodic stripping voltammetry. The peak potential was at -0.44 V vs. Ag/AgCl. The effect of various parameters (pH, ligand concentration, accumulation potential and collection time) on the response are discussed. The response was linearly related to the thallium concentration in the range 0.5-110 ng ml(-1) and 110-2000 ng ml(-1). The limit of detection was 0.2 ng ml(-1). The relative standard deviation for the determination of 80 ng ml(-1) thallium was 2.8%. Many common anions and cations did not interfere with the determination of thallium. The interference of lead was reduced by the addition of 0.003 M sodium carbonate. The voltammetric procedure was then successfully applied to the determination of thallium in various complex samples.

  1. Influence of Trace Amount of Calponin on Smooth Muscle Myosin in Different States

    Institute of Scientific and Technical Information of China (English)

    Jing-Xian YANG; Xiao-Hua FENG; Ying ZHANG; Yuan LIN

    2004-01-01

    Calponin(CaP),a thin filament-associated protein,is thought to be involved in modulating smooth muscle contractile activity,but the role and mechanism keep unknown.In this study,trace amount of calponin(TAC)was found to obviously influence myosin in different states in Ca2+-independent manner,suggesting a high efficient interaction between TAC and myosin.In this assay,the lowest ratio of CaP vs.myosin was 1:10,000,with the concentration of CaP 10,000-fold lower than that used previously.Myosin phosphorylation,myosin Mg2+-ATPase activity and protein binding activity were detected to determine the effects of TAC on the myosin in different states.The amount of precipitated myosin that bound to TAC was used as the index to determine the interaction between myosin and TAC in binding assay.Our data showed that in the absence of actin,TAC significantly increased the precipitation of unphosphorylated myosin,Ca2+-dependently or independently phosphorylated myosin by MLCK,and stimulated the Mg2+-ATPase activities of these myosins slightly but significantly.However,no obvious change of precipitation of myosin phosphorylated by PKA was observed,indicating the relatively selective effect of TAC.In the presence of actin,the increase of myosin precipitations was abolished,and no obvious change of actin precipitations and actinactivated myosin Mg2+-ATPase activities were observed implicating the high efficiency of TAC on myosin being present in the absence of actin.Although we can not give conclusive comments to our results,we propose that the high efficiency of TAC-myosin interaction is present when actin is dissociated from myosin,even if CaP/myosin ratio is very low;this high efficient interaction can be abolished by actin.However,why and how TAC can possess such a high efficiency to influence myosin and how the physiological significance of the high efficiency of TAC is in regulating the interaction between myosin and actin remain to be investigated.

  2. Characterization of elements in trace amounts in imperial topaz through neutron activation analysis; Caracterizacao de elementos em teores de traco em topazio imperial atraves da analise por ativacao neutronica

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Ester Figueiredo de [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), Belo Horizonte, MG (Brazil); Sabioni, Antonio C. S. [Ouro Preto Univ., MG (Brazil). Dept de Fisica; Ferreira, Cesar M. [Ouro Preto Univ., MG (Brazil). Dept de Geologia

    2000-07-01

    This work deals with the mineral characterization of the elements in trace amounts of imperial topaz, original form Mina Capao da Lama, Ouro Preto, MG, Brazil, through the neutron activation analysis. Recent results have permitted to quantify Cr, Cs, Mn, Na, Ga, Sb and Au. The main goal of this study is the contribution to the mineral and gemological research of the imperial topaz.

  3. Removal of trace level amounts of twelve sulfonamides from drinking water by UV-activated peroxymonosulfate.

    Science.gov (United States)

    Cui, Changzheng; Jin, Lei; Jiang, Lei; Han, Qi; Lin, Kuangfei; Lu, Shuguang; Zhang, Dong; Cao, Guomin

    2016-12-01

    Trace levels of residual antibiotics in drinking water may threaten public health and become a serious problem in modern society. In this work, we investigated the degradation of twelve sulfonamides (SAs) at environmentally relevant trace level concentrations by three different methods: ultraviolet (UV) photolysis, peroxymonosulfate (PMS) oxidation, and UV-activated PMS (UV/PMS). Sulfaguanidine, sulfadiazine, sulfamerazine, sulfamethazine, sulfathiazole, sulfamethoxydiazine, and sulfadimethoxine were be effectively removed by direct UV photolysis and PMS oxidation. However, sulfanilamide, sulfamethizole, sulfamethoxazole, sulfisoxazole, and sulfachloropyridazine were not completely degraded, despite prolonging the UV irradiation time to 30min or increasing the PMS concentration to 5.0mg·L(-1). UV/PMS provided more thorough elimination of SAs, as demonstrated by the complete removal of 200ng·L(-1) of all SAs within 5min at an initial PMS concentration of 1.0mg·L(-1). UV/PMS promoted SA decomposition more efficiently than UV photolysis or PMS oxidation alone. Bicarbonate concentration and pH had a negligible effect on SA degradation by UV/PMS. However, humic acid retarded the process. Removal of 200ng·L(-1) of each SA from a sample of sand-filtered effluent from a drinking water treatment plant (DWTPs) was quickly and completely achieved by UV/PMS. Meanwhile, about 41% of the total organic carbon (TOC) was eliminated. Scavenging experiments showed that sulfate radical (SO4(-)) was the predominant species involved in the degradation. It is concluded that UV/PMS is a rapid and efficient method for removing trace-level SAs from drinking water. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Adsorptive stripping voltammetric determination of trace amounts of lead in environmental water samples with complicated matrix

    Directory of Open Access Journals (Sweden)

    Grabarczyk M.

    2013-04-01

    Full Text Available A sensitive, simple and fast adsorptive stripping voltammetric procedure for trace determination of lead in environmental water samples has been developed. The method is based on adsorptive accumulation of the Pb(II-cupferron complex onto a hanging mercury drop electrode, followed by the reduction of the adsorbed species by a voltammetric scan using differential pulse modulation. The interference from surface active substances was eliminated by adsorption of interferents onto an Amberlite XAD-16 resin. Optimumconditions for removing the surfactants by mixing the analysed sample with resin were evaluated. The accuracy of the method was tested by analyzing certified reference material (SPS-WW1 Waste Water.

  5. Quantifying trace element and isotope fluxes at the ocean–sediment boundary: a review

    Science.gov (United States)

    Berelson, William M.; Severmann, Silke

    2016-01-01

    Quantifying fluxes of trace elements and their isotopes (TEIs) at the ocean's sediment–water boundary is a pre-eminent challenge to understand their role in the present, past and future ocean. There are multiple processes that drive the uptake and release of TEIs, and properties that determine their rates are unevenly distributed (e.g. sediment composition, redox conditions and (bio)physical dynamics). These factors complicate our efforts to find, measure and extrapolate TEI fluxes across ocean basins. GEOTRACES observations are unveiling the oceanic distributions of many TEIs for the first time. These data evidence the influence of the sediment–water boundary on many TEI cycles, and underline the fact that our knowledge of the source–sink fluxes that sustain oceanic distributions is largely missing. Present flux measurements provide low spatial coverage and only part of the empirical basis needed to predict TEI flux variations. Many of the advances and present challenges facing TEI flux measurements are linked to process studies that collect sediment cores, pore waters, sinking material or seawater in close contact with sediments. However, such sampling has not routinely been viable on GEOTRACES expeditions. In this article, we recommend approaches to address these issues: firstly, with an interrogation of emergent data using isotopic mass-balance and inverse modelling techniques; and secondly, by innovating pursuits of direct TEI flux measurements. We exemplify the value of GEOTRACES data with a new inverse model estimate of benthic Al flux in the North Atlantic Ocean. Furthermore, we review viable flux measurement techniques tailored to the sediment–water boundary. We propose that such activities are aimed at regions that intersect the GEOTRACES Science Plan on the basis of seven criteria that may influence TEI fluxes: sediment provenance, composition, organic carbon supply, redox conditions, sedimentation rate, bathymetry and the benthic nepheloid

  6. Quantifying trace element and isotope fluxes at the ocean-sediment boundary: a review

    Science.gov (United States)

    Homoky, William B.; Weber, Thomas; Berelson, William M.; Conway, Tim M.; Henderson, Gideon M.; van Hulten, Marco; Jeandel, Catherine; Severmann, Silke; Tagliabue, Alessandro

    2016-11-01

    Quantifying fluxes of trace elements and their isotopes (TEIs) at the ocean's sediment-water boundary is a pre-eminent challenge to understand their role in the present, past and future ocean. There are multiple processes that drive the uptake and release of TEIs, and properties that determine their rates are unevenly distributed (e.g. sediment composition, redox conditions and (bio)physical dynamics). These factors complicate our efforts to find, measure and extrapolate TEI fluxes across ocean basins. GEOTRACES observations are unveiling the oceanic distributions of many TEIs for the first time. These data evidence the influence of the sediment-water boundary on many TEI cycles, and underline the fact that our knowledge of the source-sink fluxes that sustain oceanic distributions is largely missing. Present flux measurements provide low spatial coverage and only part of the empirical basis needed to predict TEI flux variations. Many of the advances and present challenges facing TEI flux measurements are linked to process studies that collect sediment cores, pore waters, sinking material or seawater in close contact with sediments. However, such sampling has not routinely been viable on GEOTRACES expeditions. In this article, we recommend approaches to address these issues: firstly, with an interrogation of emergent data using isotopic mass-balance and inverse modelling techniques; and secondly, by innovating pursuits of direct TEI flux measurements. We exemplify the value of GEOTRACES data with a new inverse model estimate of benthic Al flux in the North Atlantic Ocean. Furthermore, we review viable flux measurement techniques tailored to the sediment-water boundary. We propose that such activities are aimed at regions that intersect the GEOTRACES Science Plan on the basis of seven criteria that may influence TEI fluxes: sediment provenance, composition, organic carbon supply, redox conditions, sedimentation rate, bathymetry and the benthic nepheloid inventory

  7. Kinetic-spectrophotometric determination of trace amounts of silver using the oxidation of thionine with peroxodisulfate.

    Science.gov (United States)

    Tabatabaee, Masoumeh; Nateghi, Mohamad R; Mosavi, Seyed Jaml

    2006-12-01

    A simple, rapid and sensitive method has been developed for determination of traces of silver(I) (0.2 - 13 ng mL(-1)) based on its catalytic effect on the oxidation of thionine by peroxodisulfate in the presence of 1 - 10 phenanthroline as an activator. The reaction is monitored spectrophotometrically by measuring the decrease in absorbance of thionine at 600 nm by the fixed time method. The detection limit is 0.098 ng mL(-1) and the relative standard deviation for 0.5, 3.0, 5.0 and 10 ng ml(-1) Ag(I) are 4.1, 1.37, 1.06 and 0.64%, respectively. The method is free from most interferences and it was applied to determination of silver in photographic solutions and well-water samples.

  8. Separation of traces of thorium from large amounts of uranium, by adsorption on lanthanum-ammonium oxalate

    Energy Technology Data Exchange (ETDEWEB)

    Crespi Caramella, V.; Maggi, L.; Valentini Ganzerli, M.T. E-mail: elisa@ipv36.unipv.it

    1999-10-01

    The separation of small amounts of thorium from large amounts of uranium was achieved by chromatographic columns loaded with ammonium-lanthanum oxalate LAOX, previously prepared and characterized. Good separation yields were obtained; the recovery of the elements was often greater then 95%. {sup 234}Th, naturally occurring in uranium samples, was used as a tracer of {sup 232}Th in order to study the behavior of thorium. The separation and preparation of a {sup 234}Th carrier free solution was also investigated. During thorium adsorption, trace amounts of uranium may be reduced to the +4 oxidation state. The adsorption step and the washing of the column, before thorium elution, were, therefore, run in the presence of a dilute H{sub 2}O{sub 2} solution in order to prevent uranium reduction.

  9. Quantifying Climate Feedbacks from Abrupt Changes in High-Latitude Trace-Gas Emissions

    Energy Technology Data Exchange (ETDEWEB)

    Schlosser, Courtney Adam [MIT; Walter-Anthony, Katey [University of Alaska; Zhuang, Qianlai [Purdue University; Melillo, Jerry [Marine Biological Laboratory

    2013-04-26

    Our overall goal was to quantify the potential for threshold changes in natural emission rates of trace gases, particularly methane and carbon dioxide, from pan-arctic terrestrial systems under the spectrum of anthropogenically forced climate warming, and the extent to which these emissions provide a strong feedback mechanism to global climate warming. This goal is motivated under the premise that polar amplification of global climate warming will induce widespread thaw and degradation of the permafrost, and would thus cause substantial changes in the extent of wetlands and lakes, especially thermokarst (thaw) lakes, over the Arctic. Through a coordinated effort of field measurements, model development, and numerical experimentation with an integrated assessment model framework, we have investigated the following hypothesis: There exists a climate-warming threshold beyond which permafrost degradation becomes widespread and thus instigates strong and/or sharp increases in methane emissions (via thermokarst lakes and wetland expansion). These would outweigh any increased uptake of carbon (e.g. from peatlands) and would result in a strong, positive feedback to global climate warming.

  10. Effects of trace addition of vanadium and depression amount on recrystallization temperature and mechanical performance of 5182 belts

    Institute of Scientific and Technical Information of China (English)

    GAO Jia-cheng; CHEN Zhi-qiang; MING Wen-liang; WANG Yong; CUI Xian-you; YUAN Li-jun

    2006-01-01

    Because the mechanical performances of 5182 belts used for carbonated drinks cover decrease after baking, the effects of trace addition of V and depression amount in last step on microstructure and properties of 5182 belts were investigated. The microstructure, mechanical performances and recrystallization temperature of 5182 belts and 5182V belts in different steps were analyzed comparatively with metallographic microscope, micro-hardness tester, electron universal materials test machine and differential thermal analyzer. The results show that the mechanical performances of the belts are remarkably improved by the trace addition of V and the reduction of depression amount in last step. In addition, the recrystallization temperature of the belts is also increased but not obviously. As the precipitation of V is not full, there are not enough disseminatedly distributed particles, and the recrystallization temperature increases little. However the solution strengthening and the fine grain strengthening are enough to improve the mechanical performances to satisfy customer requirements. The effects of reduction of depression amount in last step on mechanical performance were explained in view of energy. Moreover, the strengthening mechanism of V-compound interlocking grain boundary was also discussed.

  11. Detection of trace amount of arsenic in groundwater by laser-induced breakdown spectroscopy and adsorption

    Science.gov (United States)

    Haider, A. F. M. Y.; Hedayet Ullah, M.; Khan, Z. H.; Kabir, Firoza; Abedin, K. M.

    2014-03-01

    LIBS technique coupled with adsorption has been applied for the efficient detection of arsenic in liquid. Several adsorbents like tea leaves, bamboo slice, charcoal and zinc oxide have been used to enable sensitive detection of arsenic presence in water using LIBS. Among these, zinc oxide and charcoal show the better results. The detection limits for arsenic in water were 1 ppm and 8 ppm, respectively, when ZnO and charcoal were used as adsorbents of arsenic. To date, the determination of 1 ppm of As in water is the lowest concentration of detected arsenic in water by the LIBS technique. The detection limit of As was lowered to even less than 100 ppb by a combination of LIBS technique, adsorption by ZnO and concentration enhancement technique. Using the combination of these three techniques the ultimate concentration of arsenic was found to be 0.083 ppm (83 ppb) for arsenic polluted water collected from a tube-well of Farajikandi union (longitude 90.64°, latitude 23.338° north) of Matlab Upozila of Chandpur district in Bangladesh. This result compares fairly well with the finding of arsenic concentration of 0.078 ppm in the sample by the AAS technique at the Bangladesh Council of Scientific and Industrial Research (BCSIR) lab. Such a low detection limit (1 ppm) of trace elements in liquid matrix has significantly enhanced the scope of LIBS as an analytical tool.

  12. Determination of trace amounts of morphine in human plasma by anodic adsorptive stripping differential pulse voltammetry

    Institute of Scientific and Technical Information of China (English)

    Ali Niazi; Ateesa Yazdanipour

    2008-01-01

    New adsorptive anodic differential pulse stripping voltammetry method for the direct determination of morphine at trace levels in human plasma of addicts is proposed.The procedure involves an adsorptive accumulation of morphine on a HMDE,followed by oxidation of adsorbed morphine by voltammetry scan using differential pulse modulation.The optimum conditions for the analysis of morphine are pH 10.5,Eacc of - 100 mV (vs.Ag/AgCl),and tacc of 120 s.The peak current is proportional to the concentration of morphine,and a linear calibration graph is obtained at 0.01-3.10 μg mL-1.A relative standard deviation of 1.06% (n=5) was obtained,and the limit of detection was 3 ng mL- 1.The capability of the method for the analysis of real samples was evaluated by the determination of morphine in spiked human plasma and addicts human plasma with satisfactory results.

  13. Rapid synthesis of small silver nanocubes by mediating polyol reduction with a trace amount of sodium sulfide or sodium hydrosulfide.

    Science.gov (United States)

    Siekkinen, Andrew R; McLellan, Joseph M; Chen, Jingyi; Xia, Younan

    2006-12-11

    This paper describes the fastest route to monodispersed silver nanocubes. By adding a trace amount of sodium sulfide (Na(2)S) or sodium hydrosulfide (NaHS) to the conventional polyol synthesis, the reaction time was significantly shortened from 16-26 hours to 3-8 minutes. By merely adjusting the reaction time, monodispersed silver nanocubes of 25-45 nm in edge length were rapidly and routinely produced on relatively large scales. These small nanocubes are of great interest for biomedical applications by way of generating gold nanocages with plasmon resonance peaks tunable to the near-infrared region through a galvanic replacement reaction.

  14. Optical properties of a HfO2/Si stack with a trace amount of nitrogen incorporation

    Institute of Scientific and Technical Information of China (English)

    Li Ye; Jiang Tingting; Sun Qingqing; Wang Pengfei; Ding Shijin; Zhang Wei

    2012-01-01

    HfO2 films were deposited by atomic layer deposition through alternating pulsing of Hf[N(C2H5)(CH3)]4 and H2O2.A trace amount of nitrogen was incorporated into the HfO2 through ammonia annealing.The composition,the interface stability of the HfO2/Si stack and the optical properties of the annealed films were analyzed to investigate the property evolution of HfO2 during thermal treatment.With a nitrogen concentration increase from 1.41 to 7.45%,the bandgap of the films decreased from 5.82 to 4.94 eV.

  15. A solid-phase extraction method using Transcarpathian clinoptilolite for preconcentration of trace amounts of terbium in water samples.

    Science.gov (United States)

    Vasylechko, Volodymyr O; Gryshchouk, Galyna V; Zakordonskiy, Victor P; Vyviurska, Olga; Pashuk, Andriy V

    2015-01-01

    In spite of the fact that terbium is one of the rarest elements in the Earth's crust, it is frequently used for the production of high technological materials. At the result, an effective combination of sample preparation procedure and detection method for terbium ions in different matrices is highly required. The solid-phase extraction procedure with natural Transcarpathian clinoptilolite thermally activated at 350 °C was used to preconcentrate trace amounts of terbium ions in aqueous solutions for a final spectrophotometric determination with arsenazo III. Thermogravimetric investigations confirmed the existence of relations between changes that appeared during dehydratation of calcined zeolite and its sorption affinity. Since the maximum of sorption capacity towards terbium was observed at pH 8.25, a borate buffer medium (2.5 · 10(-4) М) was used to maintain ionic force and solution acidity. Terbium was quantitatively removed from the solid-phase extraction column with a 1.0 M solution of sodium chloride (pH 2.5). The linearity of the proposed method was evaluated in the range of 2.5-200 ng · mL(-1) with detection limit 0.75 ng · mL(-1). Due to acceptable recoveries (93.3-102.0 %) and RSD values (6-7.1) from spiked tap water, the developed method can be successfully applied for the determination of trace amounts of terbium ions in the presence of major components of water. Graphical abstractSorption of terbium(III) ions on clinoptilolite.

  16. Determination of trace amounts of lead and manganese in water samples after simultaneous preconcentration onto modified amberlite XAD-4 resin.

    Science.gov (United States)

    Mobarakeh, Sayed Zia Mohammadi; Afzali, Darush; Taher, Mohammad Ali; Dargahi, Roza

    2009-01-01

    A procedure for simultaneous separation and preconcentration of trace amounts of manganese and lead has been proposed. It is based on the adsorption of manganese and lead ions onto a column of Amberlite XAD-4 resin loaded with pyrocatechol reagent. Manganese and lead were quantitatively retained on the column in the pH range 4.0-6.5 at a flow rate of 2 mL/min. The manganese and lead ions were eluted with 5.0 mL of 4 M HNO3 solutions. Manganese and lead were measured by flame atomic absorption spectrometry. In this case, 100.0 ng manganese and 1000.0 ng lead were concentrated in the column from 800 mL of aqueous sample, where their concentrations were as low as 0.125 and 1.25 ng/mL, respectively. Seven replicate determinations of mixtures of 1.0 microg/mL manganese and 2.0 microg/mL lead in the final solution gave a mean absorbance of 0.1926 and 0.0832 with RSD values of +/- 1.1 and +/- 1.2%, respectively. The LODs were 1.76 ng/mL for Mn(ll) and 37.28 ng/mL for Pb(ll) (3 delta(bl)/m) in the final solution, with a preconcentration factor of 160. Sensitivities for 1% absorbance for Mn(ll) and Pb(ll) were 7.0 and 74.7 ng/mL, respectively. The interference of a large number of anions and cations has been studied and the optimized conditions were used for determination of trace amounts of manganese and lead in various environmental and standard samples.

  17. Extraction and determination of trace amounts of chlorpromazine in biological fluids using magnetic solid phase extraction followed by HPLC

    Directory of Open Access Journals (Sweden)

    Yadollah Yamini

    2014-08-01

    Full Text Available A simple, rapid and sensitive method termed as magnetic solid phase extraction (MSPE combined with high-performance liquid chromatography-ultraviolet detector (HPLC-UV has been proposed for the determination of trace amounts of chlorpromazine (CPZ in water, urine and plasma samples. The separation and determination was performed on a C18 column under the optimal chromatographic conditions. Several factors influencing the extraction efficiency of CPZ, such as pH, surfactant and adsorbent amounts, ionic strength, extraction time, sample volume and desorption conditions, were studied and optimized. Under the optimal MSPE conditions, the extraction percentage of CPZ was 74%, 27% and 16% in water, urine and plasma samples, respectively. The limits of detection (LODs of the proposed approach were 0.1, 5.0 and 10 ng/mL in water, urine and plasma samples, respectively. The relative standard deviations (RSDs based on five replicate determinations at 10 ng/mL level of CPZ was 1.2%. Good linear behaviors over the investigated concentration ranges (0.25–300 ng/mL with good coefficient of determination, R2>0.9998, were obtained. Good spike recoveries with relative errors less than 9.0% were obtained when applying the proposed method to water, urine and plasma samples.

  18. Trace amounts of furan-2-carboxylic acids determine the quality of solid agar plates for bacterial culture.

    Directory of Open Access Journals (Sweden)

    Shintaro Hara

    Full Text Available BACKGROUND: Many investigators have recognised that a significant proportion of environmental bacteria exist in a viable but non-culturable state on agar plates, and some researchers have also noticed that some of such bacteria clearly recover their growth on matrices other than agar. However, the reason why agar is unsuitable for the growth of some bacteria has not been addressed. METHODOLOGY/PRINCIPAL FINDINGS: According to the guide of a bioassay for swarming inhibition, we identified 5-hydroxymethylfuran-2-carboxylic acid (5-HMFA and furan-2-carboxylic acid (FA as factors that inhibit bacterial swarming and likely inhibit extracellular polysaccharide production on agar. The furan-2-carboxylic acids 5-HMFA and FA effectively inhibited the swarming and swimming of several environmental bacteria at concentrations of 1.8 and 2.3 µg L(-1 (13 and 21 nmol L(-1, respectively, which are equivalent to the concentrations of these compounds in 0.3% agar. On Luria-Bertani (LB plates containing 1.0% agar that had been previously washed with MeOH, a mixture of 5-HMFA and FA in amounts equivalent to their original concentrations in the unwashed agar repressed the swarming of Escherichia coli K12 strain W3110, a representative swarming bacterium. CONCLUSIONS/SIGNIFICANCE: Agar that contains trace amounts of 5-HMFA and FA inhibits the proliferation of some slow-growing or difficult-to-culture bacteria on the plates, but it is useful for single colony isolation due to the ease of identification of swarmable bacteria as the non-swarmed colonies.

  19. A simple and selective spectrophotometric flow injection determination of trace amounts of ruthenium by catalytic oxidation of safranin-O.

    Science.gov (United States)

    Rezaei, Behzad; Keyvanfard, Mohsen

    2008-03-01

    In this work, a simple, selective and rapid flow injection method has been developed for determination of ruthenium. The method is based on its catalytic effect on the oxidation of safranin-O by metaperiodate. The reaction was monitored spectrophotometrically by measuring safranin-O absorbance at lambdamax=521. The reagents and manifold variables, which have influences on the sensitivity, were investigated and the optimum conditions were established. The optimized conditions made it possible to determine ruthenium in the ranges of 0.4-20.0 ng/mL (DeltaA=0.2819CRu+1.1840) and 20.0-100.0 ng/mL (DeltaA=0.0984CRu+7.9391) with a detection limit of 0.095 ng/mL and a sample rate of 30+/-5 samples/h. Relative standard deviation for the five replicate measurements was less than 1.84%. The proposed method has been successfully applied for analysis of ultra trace amounts of ruthenium in real samples.

  20. A simple and selective spectrophotometric flow injection determination of trace amounts of ruthenium by catalytic oxidation of safranin-O

    Energy Technology Data Exchange (ETDEWEB)

    Rezaei, Behzad [Department of Chemistry, Isfahan University of Technology, Isfahan 84156-84111 (Iran, Islamic Republic of)], E-mail: rezaei@cc.iut.ac.ir; Keyvanfard, Mohsen [Faculty of Science, Majlesi Campus, Islamic Azad University, Isfahan (Iran, Islamic Republic of)

    2008-03-01

    In this work, a simple, selective and rapid flow injection method has been developed for determination of ruthenium. The method is based on its catalytic effect on the oxidation of safranin-O by metaperiodate. The reaction was monitored spectrophotometrically by measuring safranin-O absorbance at {lambda}{sub max} = 521. The reagents and manifold variables, which have influences on the sensitivity, were investigated and the optimum conditions were established. The optimized conditions made it possible to determine ruthenium in the ranges of 0.4-20.0 ng/mL ({delta}A = 0.2819C{sub Ru} + 1.1840) and 20.0-100.0 ng/mL ({delta}A = 0.0984C{sub Ru} + 7.9391) with a detection limit of 0.095 ng/mL and a sample rate of 30 {+-} 5 samples/h. Relative standard deviation for the five replicate measurements was less than 1.84%. The proposed method has been successfully applied for analysis of ultra trace amounts of ruthenium in real samples.

  1. Determination of trace amounts of Brown HT as a food dye by a CPE-scanometry method

    Directory of Open Access Journals (Sweden)

    A. Shokrollahi

    2017-01-01

    Full Text Available In this study, trace amounts of Brown HT were extracted, pre-concentrated and determined by cloud point extraction-scanometry (CPE-scanometry as a simple, fast and inexpensive method. The procedure is based on CPE of Brown HT from an aqueous solution, diluting the extracted surfactant-rich phase with ethanol to 500 μL, transferring the appropriate volume to Plexiglas® cells and scanning the cells. Then, the colour of each cell was analyzed by software written in visual basic (VB 6 into red, green and blue values. Effective parameters for the extraction efficiency, such as the pH of the system, the concentration of surfactant, the equilibration temperature and equilibration time, were investigated and optimized. Under optimal conditions, the calibration curve was linear in the range of 0.06–2.60 mg L−1. The detection limit of the proposed method was 0.04 mg L−1. In addition, the effects of some foreign species, including cations, anions and dyes, were investigated. The method was applied successfully for the determination of Brown HT in some water samples.

  2. Determination of trace amounts of ethylene glycol and its analogs in water matrixes by liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Tran, Buu N; Okoniewski, Richard; Bucciferro, Anthony; Jansing, Robert; Aldous, Kenneth M

    2014-01-01

    Contamination of drinking water by ethylene glycol (EG) is a public health concern. EG causes adverse health effects in humans and animals, including cardiopulmonary and acute renal failure. EG and other glycols, such as propylene glycol (PG) are major components in antifreeze liquids, which may be the main source of contamination of ground water. A sensitive LC/electrospray ionization (ESI)-MS/MS method was developed to measure trace amounts of EG, diethylene glycol, and 1,2- and 1,3-PG in several water sources, including municipal tap, lake, river, and salinated water. In this method, glycols in water samples were derivatized with benzoyl chloride by the Schotten-Baumann reaction, followed by liquid-liquid extraction using pentane as the organic solvent prior to the LC/ESI-MS/MS determination. QC included analysis of a method blank and samples fortified at low and high levels. Analytical data showed excellent linear calibration for all observed glycols, with good precision and accuracy. The method detection limits for the studied glycols ranged from 1.9 to 6.1 ng/mL across the water matrixes tested. This method is suitable to help assess water quality in areas that may be prone to glycol contamination.

  3. Utility of solid phase spectrophotometry for the modified determination of trace amounts of cadmium in food samples.

    Science.gov (United States)

    Amin, Alaa S; Gouda, Ayman A

    2012-05-01

    A modified selective, highly sensitive and accurate procedure for the determination of trace amounts of cadmium which reacts with 1-(2-benzothiazolylazo)-2-hydroxy-3-naphthoic acid (BTAHNA) to give a deep violet complex with high molar absorptivity (7.05×10(6)Lmol(-1) cm(-1), 3.92×10(7)Lmol(-1)cm(-1), 1.78×10(8)Lmol(-1)cm(-1), and 4.10×10(8)Lmol(-1)cm(-1)), fixed on a Dowex 1-X8 type anion-exchange resin for 10mL, 100mL, 500mL, and 1000mL, respectively. Calibration is linear over the range 0.2-3.5μgL(-1) with RSD of ⩽1.14% (n=10). The detection and quantification limits were calculated. Increasing the sample volume can enhance the sensitivity. The method has been successfully applied for the determination of Cd(II) in food samples, water samples and some salts samples without interfering effect of various cations and anions.

  4. Graphene for separation and preconcentration of trace amounts of cobalt in water samples prior to flame atomic absorption spectrometry

    Directory of Open Access Journals (Sweden)

    Yukun Wang

    2016-09-01

    Full Text Available A new sensitive and simple method was developed for the preconcentration of trace amounts of cobalt (Co using 1-(2-pyridylazo-2-naphthol (PAN as chelating reagent prior to its determination by flame atomic absorption spectrometry. The proposed method is based on the utilization of a column packed with graphene as sorbent. Several effective parameters on the extraction and complex formation were selected and optimized. Under optimum conditions, the calibration graph was linear in the concentration range of 5.0–240.0 μg L−1 with a detection limit of 0.36 μg L−1. The relative standard deviation for ten replicate measurements of 20.0 and 100.0 μg L−1 of Co were 3.45 and 3.18%, respectively. Comparative studies showed that graphene is superior to other adsorbents including C18 silica, graphitic carbon, and single- and multi-walled carbon nanotubes for the extraction of Co. The proposed method was successfully applied in the analysis of four real environmental water samples. Good spiked recoveries over the range of 95.8–102.6% were obtained.

  5. Development of a selective and sensitive flotation method for determination of trace amounts of cobalt, nickel, copper and iron in environmental samples.

    Science.gov (United States)

    Karimi, H; Ghaedi, M; Shokrollahi, A; Rajabi, H R; Soylak, M; Karami, B

    2008-02-28

    A simple, selective and rapid flotation method for the separation-preconcentration of trace amounts of cobalt, nickel, iron and copper ions using phenyl 2-pyridyl ketone oxime (PPKO) has been developed prior to their flame atomic absorption spectrometric determinations. The influence of pH, amount of PPKO as collector, type and amount of eluting agent, type and amount of surfactant as floating agent and ionic strength was evaluated on the recoveries of analytes. The influences of the concomitant ions on the recoveries of the analyte ions were also examined. The enrichment factor was 93. The detection limits based on 3 sigma for Cu, Ni, Co and Fe were 0.7, 0.7, 0.8, and 0.7 ng mL(-1), respectively. The method has been successfully applied for determination of trace amounts of ions in various real samples.

  6. Quantifying trace elements in the emitted particulate matter during cooking and health risk assessment.

    Science.gov (United States)

    Gorjinezhad, Soudabeh; Kerimray, Aiymgul; Amouei Torkmahalleh, Mehdi; Keleş, Melek; Ozturk, Fatma; Hopke, Philip K

    2017-04-01

    Particulate matter (PM) measurements were conducted during heating corn oil, heating corn oil mixed with the table salt and heating low fat ground beef meat using a PTFE-coated aluminum pan on an electric stove with low ventilation. The main objectives of this study were to measure the size segregated mass concentrations, emission rates, and fluxes of 24 trace elements emitted during heating cooking oil or oil with salt and cooking meat. Health risk assessments were performed based on the resulting exposure to trace elements from such cooking activities. The most abundant elements (significantly different from zero) were Ba (24.4 ug m(-3)) during grilling meat and Ti during heating oil with salt (24.4 ug m(-3)). The health assessment indicates that the cooking with an electric stove with poor ventilation leading to chronic exposures may pose the risk of significant adverse health effects. Carcinogenic risk exceeded the acceptable level (target cancer risk 1 × 10(-6), US EPA 2015) by four orders of magnitude, while non-carcinogenic risk exceeded the safe level (target HQ = 1, US EPA 2015) by a factor of 5-20. Cr and Co were the primary contributors to the highest carcinogenic and non-carcinogenic risks, respectively.

  7. Determination of Trace Amount of Polycyclic Aromatic Hydrocarbons in Urban Sewage by Solid-phase Extraction Coupled with High Performance Liquid Chromatograph

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    [Method] This study aimed to determine trace amount of polycyclic aromatic hydrocarbons(PAHs) in urban sewage by using solid-phase extraction(SPE) coupled with high performance liquid chromatograph(HPLC).[Method] From the aspects of solid-phase extraction column,elution solvent,elution volume,elution speed and so forth,the test conditions of SPE-HPLC method were optimized,and trace amount of PAHs in urban sewage was determined.[Result] The optimized solid-phase extraction conditions were SUPELCLEAN LC-18 so...

  8. Comparison of Packed Beds and Qiagen Columns for Recovering Trace Amounts of B. anthracis DNA from Liquid Suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Sorensen, K; Arroyo, E; Erler, A; Christian, A T; Camp, D; Wheeler, E K

    2006-06-23

    The goal of this work was to optimize and evaluate LLNL's in-bed amplification technology to improve the level of detection for suspensions containing trace amounts of anthracis DNA. The binding/cleaning performance of the packed bed is compared to the conventional commercial approach; Qiagen column cleanup and elution, followed by detection through an ex-situ amplification process. Five liquid suspensions were spiked with B.anthracis DNA in concentration series. These suspensions were: (1) water, (2) water with EDTA, (3) dirty water from carpet extraction, (4) dirty carpet extraction with phosphate buffered saline (PBS) plus 0.1% Tween 20 plus 0.1% gelatin, and (5) a subway aerosol collected in water. Each suspension matrix was spiked with DNA and injected (in replicate) into either Qiagen Microcolumns (using the kit processing instructions) or LLNL's packed bed (using the LLNL in-bed purification and amplification protocol). The process output was assayed by quantitative polymerase chain reaction (QPCR). Table ES-1 shows the level of DNA (pg per 100 uL of input suspension) that resulted in successful amplification for all reactions (X=Y), and the level for which at least one of the reactions was successful (X>0). For each suspension and DNA concentration, there were Y QPCR assays of which X showed successful amplification. LLNL's packed bed technology outperformed Qiagen Microcolumns for all five suspensions, typically by one order of magnitude in both the limit of assured detection (all reactions positive), and the lower limit of detection (some reactions positive).

  9. Large-scale structures in tetrahydrofuran-water mixture with a trace amount of antioxidant butylhydroxytoluene (BHT).

    Science.gov (United States)

    Li, Zhiyong; Cheng, He; Li, Junyu; Hao, Jinkun; Zhang, Li; Hammouda, Boualem; Han, Charles C

    2011-06-23

    Author: Because of the closed-loop phase diagram of tetrahydrofuran (THF)-water mixture, THF aqueous solution naturally exhibits concentration fluctuations near the phase boundary. Besides the fast mode induced by concentration fluctuations, the 4.5% mole fraction THF aqueous solution is also characterized by a slow mode. The existence of a trace amount of butylhydroxytoluene (BHT) antioxidant in commercial THF strongly influences the slow mode in 4.5% mole fraction THF aqueous solution. A core-shell structure with a BHT core and a shell made from THF-rich THF-D(2)O mixture was identified by the combination of dynamic laser light scattering (DLS) and small-angle neutron scattering (SANS). BHT is hydrophobic, stabilized by a THF-rich domain in THF aqueous solution and acts as a tracer to make the large-scale structure (slow mode) "visible" through SANS because of its larger contrast with the solvent. In contrast, this large-scale structure was almost not detectable by SANS when BHT was removed from the THF-D(2)O mixture. Combined UV-vis, DLS, and static light scattering (SLS) indicated that slow-moving objects do exist and that their sizes almost do not change, but their concentration decreases to a small but nonzero value at the infinite dilution limit. The origin of the elusive large-scale structure at zero BHT concentration is still not clear, but it might be associated with some hydrophobic impurities or nanobubbles. However, a polydisperse sphere model of ∼8.5% mole fraction THF-D(2)O mixture can fit the structure with a radius of ∼100 nm, which gives the temperature-dependent low-q SANS profiles of 4.5% mole fraction THF aqueous solution at zero BHT concentration.

  10. Chemical amplification methods for the sequential determination of trace amounts of ruthenium by titrimetric and spectrophotometric procedures.

    Science.gov (United States)

    El-Shahawi, M S; Barakat, S A

    1995-11-01

    Two simple, inexpensive and rapid iodometric and spectrophotometric procedures were developed for trace amount determination of ruthenium. The proposed methods were based on the oxidation of ruthenium(II or III) with sodium periodate at pH 2.4-3.6, masking the excess periodate with sodium molybdate. The released iodate was then allowed to react with KI at pH 3, with subsequent determination of the released iodine spectrophotometry as triiodide at 350 nm or iodometry with 0.005 M sodium thiosulphate. This procedure offers an 18- and 15-fold amplification per Ru(II) or Ru(III) ion, respectively. Alternatively, the produced iodine was extracted with CHCl(3), shaken with an aqueous solution of sodium sulphite and the produced iodide ion was then allowed to react with bromine (or sodium periodate). The released iodate was subsequently determined by iodometry or spectrophotometry after addition of KI. The bromine and sodium periodate oxidation procedures offered 90- and 360-fold amplification per ruthenium(III) ion, and 108- and 432-fold amplification per ruthenium(II) ion. Ruthenium(IV) content was determined by these procedures after prior reduction to Ru(III) with sulphurous acid. The binary mixtures Ru(II)-Ru(III); Ru(III)-Ru(IV) and Ru(II)-Ru(IV) in aqueous solution at concentration 0.05 mug ml(-1) were successfully analyzed by the developed procedures. The utility of the proposed methods for the analysis of ruthenium in its complexes was demonstrated. Natural seawater and seawater spiked with ruthenium were analyzed satisfactorily.

  11. Comparison of Packed Beds and Qiagen Columns for Recovering Trace Amounts of B. anthracis DNA from Liquid Suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Sorensen, K; Arroyo, E; Erler, A; Christian, A T; Camp, D; Wheeler, E K

    2006-06-23

    The goal of this work was to optimize and evaluate LLNL's in-bed amplification technology to improve the level of detection for suspensions containing trace amounts of anthracis DNA. The binding/cleaning performance of the packed bed is compared to the conventional commercial approach; Qiagen column cleanup and elution, followed by detection through an ex-situ amplification process. Five liquid suspensions were spiked with B.anthracis DNA in concentration series. These suspensions were: (1) water, (2) water with EDTA, (3) dirty water from carpet extraction, (4) dirty carpet extraction with phosphate buffered saline (PBS) plus 0.1% Tween 20 plus 0.1% gelatin, and (5) a subway aerosol collected in water. Each suspension matrix was spiked with DNA and injected (in replicate) into either Qiagen Microcolumns (using the kit processing instructions) or LLNL's packed bed (using the LLNL in-bed purification and amplification protocol). The process output was assayed by quantitative polymerase chain reaction (QPCR). Table ES-1 shows the level of DNA (pg per 100 uL of input suspension) that resulted in successful amplification for all reactions (X=Y), and the level for which at least one of the reactions was successful (X>0). For each suspension and DNA concentration, there were Y QPCR assays of which X showed successful amplification. LLNL's packed bed technology outperformed Qiagen Microcolumns for all five suspensions, typically by one order of magnitude in both the limit of assured detection (all reactions positive), and the lower limit of detection (some reactions positive).

  12. Tracing Mantle Plumes: Quantifying their Morphology and Behavior from Seismic Tomography

    Science.gov (United States)

    O'Farrell, K. A.; Eakin, C. M.; Jones, T. D.; Garcia, E.; Robson, A.; Mittal, T.; Lithgow-Bertelloni, C. R.; Jackson, M. G.; Lekic, V.; Rudolph, M. L.

    2016-12-01

    Hotspot volcanism provides a direct link between the deep mantle and the surface, but the location, depth and source of the mantle plumes that feed hotspots are highly controversial. In order to address this issue it is important to understand the journey along which plumes have travelled through the mantle. The general behavior of plumes in the mantle also has the potential to tell us about the vigor of mantle convection, net rotation of the mantle, the role of thermal versus chemical anomalies, and important bulk physical properties of the mantle such as the viscosity profile. To address these questions we developed an algorithm to trace plume-like features in shear-wave (Vs) seismic tomographic models based on picking local minima in velocity and searching for continuous features with depth. We apply this method to several of the latest tomographic models and can recover 30 or more continuous plume conduits that are >750 km long. Around half of these can be associated with a known hotspot at the surface. We study the morphology of these plume chains and find that the largest lateral deflections occur near the base of the lower mantle and in the upper mantle. We analyze the preferred orientation of the plume deflections and their gradient to infer large scale mantle flow patterns and the depth of viscosity contrasts in the mantle respectively. We also retrieve Vs profiles for our traced plumes and compare with velocity profiles predicted for different mantle adiabat temperatures. We use this to constrain the thermal anomaly associated with these plumes. This thermal anomaly is then converted to a density anomaly and an upwelling velocity is derived. We compare this to buoyancy fluxes calculated at the surface and use this in conjunction with our measured plume tilts/deflections to estimate the strength of the "mantle wind".

  13. Quantifying traces of tool use: a novel morphometric analysis of damage patterns on percussive tools.

    Directory of Open Access Journals (Sweden)

    Matthew V Caruana

    Full Text Available Percussive technology continues to play an increasingly important role in understanding the evolution of tool use. Comparing the archaeological record with extractive foraging behaviors in nonhuman primates has focused on percussive implements as a key to investigating the origins of lithic technology. Despite this, archaeological approaches towards percussive tools have been obscured by a lack of standardized methodologies. Central to this issue have been the use of qualitative, non-diagnostic techniques to identify percussive tools from archaeological contexts. Here we describe a new morphometric method for distinguishing anthropogenically-generated damage patterns on percussive tools from naturally damaged river cobbles. We employ a geomatic approach through the use of three-dimensional scanning and geographical information systems software to statistically quantify the identification process in percussive technology research. This will strengthen current technological analyses of percussive tools in archaeological frameworks and open new avenues for translating behavioral inferences of early hominins from percussive damage patterns.

  14. Chromatographic analysis on trace amount harmful substance in water%水环境中痕量有害物质色谱分析

    Institute of Scientific and Technical Information of China (English)

    孙鹏; 李伟娟

    2015-01-01

    This article describes the chromatographic analysis on trace amount harmful substance in terms of current state and features of water environment.%文章针对水环境的现状以及特点,对其中痕量有害物质进行了系统的色谱分析.

  15. A sensitive and rapid HPLC-MS/MS method for the quantitative determination of trace amount of bromocriptine in small clinical prolactinoma tissue.

    Science.gov (United States)

    Zang, Qingce; Liu, Yang; He, Jiuming; Yue, Xiaofei; Zhang, Ruiping; Wang, Renzhi; Abliz, Zeper

    2015-05-01

    Usually, insufficient intratumoral concentration of therapeutic drugs is one of the reasons for tumor treatment failure. However, little is known about intratumoral distribution of bromocriptine in non-responding prolactinomas because of extremely low drug concentration and small prolactinoma tissue samples. In this study, a sensitive, rapid and high-throughput quantitative bioanalytical method has been established by using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) for the determination of bromocriptine at trace level in human prolactinoma tissue. As little as 20 mg (wet weight) tissue sample was required and total analysis time was 6 min in this method. The assay quantifies over a linear range of 50 fg/mg to 5 pg/mg, and has a 25 fg/mg limit of detection at a signal/noise ratio of 3. This validated method was successfully used to quantitatively determine bromocriptine in clinical post-operative bromocriptine-sensitive and -resistant prolactinomas. The results revealed bromocriptine concentration in resistant prolactinomas (0.49-1.25 pg/mg) was significantly higher than that in sensitive prolactinomas (0.057-0.47 pg/mg). These results provided direct evidence to demonstrate the reseaon for failure of bromocriptine treatment in some patients with prolactinoma was "intrinsic" tumor (cell) resistence, rather than insufficient drug concentration in tumor tissue. Additionaly, this HPLC-MS/MS method has been shown to be suitable for bromocriptine analysis in small amount tissue sample and could be adapted for therapeutic drug monitoring of other clinical medicine.

  16. Tracing and quantifying groundwater inflow into lakes using a simple method for radon-222 analysis

    Directory of Open Access Journals (Sweden)

    T. Kluge

    2007-09-01

    Full Text Available Due to its high activities in groundwater, the radionuclide 222Rn is a sensitive natural tracer to detect and quantify groundwater inflow into lakes, provided the comparatively low activities in the lakes can be measured accurately. Here we present a simple method for radon measurements in the low-level range down to 3 Bq m−3, appropriate for groundwater-influenced lakes, together with a concept to derive inflow rates from the radon budget in lakes. The analytical method is based on a commercially available radon detector and combines the advantages of established procedures with regard to efficient sampling and sensitive analysis. Large volume (12 l water samples are taken in the field and analyzed in the laboratory by equilibration with a closed air loop and alpha spectrometry of radon in the gas phase. After successful laboratory tests, the method has been applied to a small dredging lake without surface in- or outflow in order to estimate the groundwater contribution to the hydrological budget. The inflow rate calculated from a 222Rn balance for the lake is around 530 m³ per day, which is comparable to the results of previous studies. In addition to the inflow rate, the vertical and horizontal radon distribution in the lake provides information on the spatial distribution of groundwater inflow to the lake. The simple measurement and sampling technique encourages further use of radon to examine groundwater-lake water interaction.

  17. Cloud Point Extraction for the Determination of Trace Amounts of Cobalt in Water and Food Samples by Flame Atomic Absorption Spectrometry

    Directory of Open Access Journals (Sweden)

    Shangzhi Wang

    2013-01-01

    Full Text Available A cloud point extraction (CPE procedure which was developed for the separation and preconcentration of trace amounts of cobalt is combined with flame atomic absorption spectrometry (FAAS to determine trace amounts of cobalt in water and food samples. The procedure is based on the formation of the hydrophobic complex between Co(II and 4-methoxy-2-sulfo-benzenediazoaminoazo-benzene (MOSDAA followed by its extraction into a Triton X-114 surfactant-rich phase. The parameters such as pH of sample, concentrations of MOSDAA and Triton X-114, equilibrium temperature, and equilibrium time, which affect both complexation and extraction, are optimized. Under the selected optimum conditions, the preconcentration of 10.0 mL, 0.1 μg mL−1 Co(II solution results in a limit of detection of 0.47 ng mL−1 (3σ and an enrichment factor of 19. A relative standard deviation of 2.78% (,  μg mL−1 for the determination of Co(II is obtained. The proposed method was applied for the determination of trace amounts of cobalt in river water and millet samples with satisfactory results.

  18. Determination of trace amounts of Ga(III) by adsorptive stripping voltammetry with in situ plated bismuth film electrode.

    Science.gov (United States)

    Grabarczyk, Malgorzata; Wasąg, Joanna

    2015-11-01

    The determination of trace gallium using adsorptive stripping voltammetry at an in situ plated bismuth film electrode was described. The method was based on simultaneous film formation and the Ga(III)-cupferron complex preconcentration at -0.65 V and its cathodic stripping during the potential scan. The effect of Bi(III) and cupferron concentration, the influence of deposition potential and time, and the scan rate on the determination of Ga(III) were studied. A linear response in the concentration range of 3×10(-10) to 3×10(-7) mol L(-1) (r=0.998) was obtained with detection limit of 1.05×10(-10) mol L(-1) using accumulation time of 180 s. Finally, the bismuth film electrode was successfully applied for the determination of Ga(III) in certified reference material seawater NASS-5 with satisfactory results.

  19. Real-time PCR-based assay to quantify the relative amount of human and mouse tissue present in tumor xenografts

    Directory of Open Access Journals (Sweden)

    Alcoser Sergio Y

    2011-12-01

    Full Text Available Abstract Background Xenograft samples used to test anti-cancer drug efficacies and toxicities in vivo contain an unknown mix of mouse and human cells. Evaluation of drug activity can be confounded by samples containing large amounts of contaminating mouse tissue. We have developed a real-time quantitative polymerase chain reaction (qPCR assay using TaqMan technology to quantify the amount of mouse tissue that is incorporated into human xenograft samples. Results The forward and reverse primers bind to the same DNA sequence in the human and the mouse genome. Using a set of specially designed fluorescent probes provides species specificity. The linearity and sensitivity of the assay is evaluated using serial dilutions of single species and heterogeneous DNA mixtures. We examined many xenograft samples at various in vivo passages, finding a wide variety of human:mouse DNA ratios. This variation may be influenced by tumor type, number of serial passages in vivo, and even which part of the tumor was collected and used in the assay. Conclusions This novel assay provides an accurate quantitative assessment of human and mouse content in xenograft tumors. This assay can be performed on aberrantly behaving human xenografts, samples used in bioinformatics studies, and periodically for tumor tissue frequently grown by serial passage in vivo.

  20. Quantification of Trace Amounts of Impurities in High Purity Cobalt by High Resolution Inductively Coupled Plasma Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    Hua Lin XIE; Xi Du NIE; You Gen TANG

    2006-01-01

    An analytical method using high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) for rapid simultaneous determination of Be, Mg, Al, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, As, Se, Mo, Ag, Cd, Sn, Sb, Ba, Pt, Au and Pb in high purity cobalt was described. Sample digestions were performed in closed microwave vessels using HNO3 and HCl. The matrix effects due to thc presence of excess HCl and Co were evaluated. The usefulness of high mass resolution for overcoming some spectral interference was demonstrated. The optimum conditions for the determination was tested and discussed. Correction for matrix effects, Sc, Rh and Bi were used as internal standards. The detection limits is 0.003-0.57 μg/g, the recovery ratio is 92.2%- 111.2%, and the RSD is less than 3.6%. The method is accurate, quick and convenient. It has been applied to the determination of trace impurities in high purity cobalt with satisfactory results.

  1. Quantification of trace amounts of impurities in high purity cobalt by high resolution inductively coupled plasma mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    XIE Hualin; HUANG Kelong; NIE Xidu; TANG Yougen

    2007-01-01

    An analytical method using high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) for rapid simultaneous determination of 24 elements (Be, Mg, Al, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, As, Se, Mo, Ag, Cd, Sn,Sb, Ba, Pt, Au, and Pb) in high purity cobalt was described. Sample digestions were performed in closed microwave vessels using HNO3 and HCl. The matrix effects because of the presence of excess HCl and Co were evaluated. The usefulness of high mass resolution for overcoming some spectral interference was demonstrated. The optimum conditions for the determination were tested and discussed. The standard addition method was employed for quantitative analysis. The detection limits were 0.016-1.50 μg.g-1, the recovery ratios were 92.2%-111.2%, and the RSD was less than 3.6%. The method was accurate, quick, and convenient. It was applied to the determination of trace impurities in high purity cobalt with satisfactory results.

  2. Determination of trace amounts of nitrogen in uranium based samples by ion chromatography (IC) without Kjeldahl distillation.

    Science.gov (United States)

    Verma, Poonam; Rastogi, Ramakant K; Ramakumar, Karanam L

    2007-07-23

    A simple, sensitive and fast ion chromatographic (IC) method with suppressed conductivity detection is described for the determination of traces of nitrogen in uranium based fuel materials. Initially a method was developed to determine nitrogen as NH4(+) using cation exchange column after matrix separation by Kjeldahl distillation. The method was then improved by eliminating this distillation. Matrix separation after sample dissolution was done by hydrolyzing and filtering off the polyvalent cations. This had helped in reducing both the sample size and analysis time. Optimization of dissolution conditions for various kinds of uranium based samples was done to keep acid content minimum; a prerequisite chromatographic condition. The calibration plot for nitrogen was linear in the concentration range of 0.02-1 mg L(-1) with regression coefficient of 0.9999. The relative standard deviation (R.S.D.) obtained in this method (100 microL injected) was 3% and 2% in 9 replicates at nitrogen level of 28 and 55 ng g(-1), respectively. Detection limit based on S/N=3 (100 microL injected) as well as three times of variation in blank value was 4 ng g(-1). The developed method was authenticated by comparison with certified uranium-alloy standard as well as with independent indophenol photometry method. The developed method was applied to uranium-alloy, uranium-metal, sintered UO2 pellets and sintered UO2 microspheres samples.

  3. Spectrophotometric Determination of the Trace Amount of Thallium in Water and Urine Samples by Novel Oxidative Coupling Reaction

    Directory of Open Access Journals (Sweden)

    P. Nagaraja

    2009-01-01

    Full Text Available A novel, simple, rapid, sensitive and selective method has been proposed for the trace determination of thallium by spectrophotometric detection. This method is based on the oxidation of MBTH (3-methyl-2-benzothiazolinone hydrazone hydrochloride by thallium(III to form diazonium cation, which couples with IPH (Imipramine hydrochloride in phosphoric acid medium at room temperature giving a blue colored species having a maximum absorption at 635 nm. The reagents and manifold variables influences on the sensitivity were investigated and the optimum reaction conditions have been established. The calibration curve was found to be linear over the range 0.1-5 μg mL-1 with the molar absorptivity and Sandell’s sensitivity of 2.9x104 L mol-1 cm-1, 0.0071 μg cm-2 respectively. The tolerance limit of the method towards various ions usually associated with thallium has been detected. The relative standard deviation for five replicate determination of 2μg mL-1 thallium was 0.47%. The method has been successfully applied for the determination of thallium(ІΙΙ and thallium(I in synthetic, standard reference materials, water and urine samples with satisfactory results. The performance of the proposed method was evaluated in terms of student’s t-test and variance ratio F-test, to find out the significance of proposed method over the reported methods.

  4. Investigation of analytical performance for rapidly synergistic cloud point extraction of trace amounts of copper combined with spectrophotometric determination

    Science.gov (United States)

    Wen, Xiaodong; Ye, Liqing; Deng, Qingwen; Peng, Li

    2011-12-01

    In this work, an improved preconcentration method named as rapidly synergistic cloud point extraction (RS-CPE) was established for copper preconcentration and determination. Non-ionic surfactant Triton X-100 (TX-100) was used as extractant. Octanol worked as cloud point revulsant and synergic reagent, which successfully decreased the cloud point temperature (CPT) of TX-100 to realize the room temperature (about 20 °C) CPE without heating. The established RS-CPE pretreatment was simple, rapid and effective. Compared with traditional CPE (about 40 min for heating, incubation and cooling), the extraction time of the proposed method was very short (1 min). The improved extraction technique RS-CPE was combined with traditional spectrophotometer to improve the analytical performance and expand the application of spectrophotometric determination. The influence factors relevant to RS-CPE, such as concentrations of TX-100 and octanol, concentration of chelating agent, pH, conditions of phase separation, salt effect, environmental temperature and instrumental conditions, were studied in detail. Under the optimal conditions, the limit of detection (LOD) for copper was 0.4 μg L -1, with sensitivity enhancement factor (EF) of 18. The proposed method was applied to the determination of trace copper in real samples and certified samples with satisfactory analytical results.

  5. Preconcentration and Determination of Trace Amounts of Heavy Metals in Water Samples Using Membrane Disk and Flame Atomic Absorption Spectrometry

    Institute of Scientific and Technical Information of China (English)

    ALI,Moghimi

    2007-01-01

    A fast and simple method for preconcentration of Ni2+, Cd2+, Pb2+, Zn2+, Cu2+ and Co2+ from natural water samples was developed. The metal ions were complexed with sodium diethyldithiocarbamate (Na-DDTC), then adsorbed onto octadecyl silica membrane disk, recovered and determined by FAAS. Extraction efficiency, influence of sample volume and eluent flow rates, effects of pH, amount of Na-DDTC, nature and amount of eluent for elution of metal ions from membrane disk, break through volume and limit of detection have been evaluated. The effect of foreign ions on the percent recovery of heavy metal ions has also been studied. The limit of detection of the proposed method for Ni2+, Cd2+, Pb2+, Zn2+, Cu2+ and Co2+was found to be 2.03, 0.47, 3.13, 0.44, 1.24 and 2.05ng·mL-1, respectively. The proposed (DDTC) method has been successfully applied to the recovery and determination of heavy metal ions in different water samples.

  6. Coprecipitation of trace amounts of silicon with aluminum hydroxide and the determination by flame atomic absorption spectrometry

    Directory of Open Access Journals (Sweden)

    Ardeshir Shokrollahi

    2014-01-01

    Full Text Available A simple preconcentration method of silicon based on coprecipitation with aluminum hydroxide prior to its flame atomic absorption (FAAS determination was established. The recovery values of analyte ion was higher than 95%. The parameters including types of hydroxide ion source for precipitation, acid type for dissolution step, amount of aluminum ion as collector, pH, temperature, standing and centrifuge time, and sample volume were optimized for the quantitative recovery of the analyte. The influences of matrix ions were also examined. The relative standard deviation was found to be 3.2%. The limit of detection was calculated as (0.1 mg L-1. The preconcentration factor is 100 for (200 mL solution. The proposed method was successfully applied for the determination of silicon in some water and alloy samples.

  7. Simultaneous spectrophotometric determination of trace amount of malachite green and crystal violet in water after cloud point extraction using partial least squares regression.

    Science.gov (United States)

    An, Lin; Deng, Jian; Zhou, Liang; Li, Hui; Chen, Fei; Wang, Hui; Liu, Yating

    2010-03-15

    In this work, a new method has been proposed to simultaneously determine the trace amount of malachite green and crystal violet from aqueous solution by spectrophotometry after cloud point extraction (CPE) using partial least squares regression. The optimal extraction and operating conditions, such as pH, reagents concentration and effect of time and temperature, and so on, have been investigated using the non-ionic surfactant Triton X-114. The maximum absorption wavelength for malachite green and crystal violet is 624 and 579 nm, respectively; linearity is obeyed in the range of 9.9-800 and 16-1000 ng mL(-1) with detection limit of 2.9 and 4.8 ng mL(-1), and the root mean square error of prediction (RMSEP) are 0.0197 and 0.0343, respectively. The proposed method has been applied successfully to simultaneously determine the trace amount of malachite green and crystal violet in real matrix samples with the recoveries of 92.45-102.5%.

  8. Micro-electrodeposition in the presence of ionic liquid for the preconcentration of trace amounts of Fe, Co, Ni and Zn from aqueous samples

    Energy Technology Data Exchange (ETDEWEB)

    Zawisza, Beata, E-mail: beata.zawisza@us.edu.pl; Sitko, Rafał

    2013-04-01

    The paper presents the preconcentration of trace elements via electrodeposition onto a (micro)aluminum cathode in the presence of ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF{sub 6}] as a supporting electrolyte. The advantages of the proposed method include very simple instrumentation for the preconcentration of trace elements and low-cost reagents. The experiment showed that the use of ionic liquid in the electrodeposition process significantly improves sensitivity, recovery and detection limits for the determination of trace amounts of iron, cobalt, nickel and zinc. The preconcentrated metals were determined using X-ray fluorescence spectrometry. The optimum parameters for electrodeposition such as pH, the volume of the analyzed solution, the voltage and the deposition time were studied. Under the optimized conditions, the detection limits were 5, 2, 3 and 6 μg L{sup −1} for iron, cobalt, nickel and zinc, respectively. The precision and recovery of the method were in the range of 3–5.5%, and 92–103%, respectively. The calibration was performed using aqueous standards of Fe(III), Co(II), Ni(II) and Zn(II) in the range 0.01–0.25 mg L{sup −1}. The method was applied successfully in water analysis. - Highlights: ► A novel method of micro sample preparation for XRF analysis is proposed. ► Electrodeposition is performed using microcathode. ► A novel modification of electrodeposition method is using ionic liquid. ► The method can be combined with many techniques for multielement trace analysis.

  9. Influencing Factors and Control Measures in Inorganic Trace Amount Analysis%无机痕量分析的影响因素与控制措施

    Institute of Scientific and Technical Information of China (English)

    冯志强; 刘宁; 赵颖彬; 逄小青; 陈玲

    2015-01-01

    为获得准确的分析结果,研究了器皿、水以及溶剂等因素对无机痕量分析过程的影响。结果表明聚丙烯材质的器皿可以有效降低试验的空白值,一级水以及电子级的试剂中Si、 Na、 Ca元素的含量低于ICP光谱仪的检测限,满足无机痕量分析的需要。同时,提出了样品处理、溶剂纯化和实验器皿清洗过程中的注意事项,严格防止所用器皿、化学试剂、溶剂等受到污染,减少和控制空白信号。%The choice of the experimental vessels, water and solvent for the use in inorganic trace amount anlysis were studied in order to get accurate analysis result. The result of experiment showed that polypropylene was a good material for container because the value of blank can be decreased effectively. The content of silicon element, sodium element, calcium element in stair water and electric grade reagent was under the detectability of Inductively Coupled Plasma ( ICP) spectrum apparatus which met the requirement of inorganic trace analysis. The noticeable proceeding in the process of sample disposal, solvent purification and the vessel washing was given. The container, chemical reagent and solvent in inorganic trace amount analysis should be treated carefully to avoid any pollution, which will reduce and control the values of blank.

  10. Development of a flotation method for preconcentration-separation of trace amounts of some metal ions in plant tissues prior to their FAAS determinations

    Directory of Open Access Journals (Sweden)

    M. Ghaedi

    2010-01-01

    Full Text Available An efficient flotation method based on the combination of flame atomic absorption spectrometry (FAAS and separation and preconcentration step for determination of Cr3+, Cu 2+, Co2+, Ni2+, Zn2+, Cd 2+, Fe3+ and Pb2+ ions in various real samples by the possibility of applying bis(2-hydroxyacetophenone-1,4-butanediimine (BHABDI as a new collector was studied. The influence of pH, amount of BHABDI as collector, sample matrix, type and amount of eluting agent, type and amount of surfactant as floating agent, ionic strength and air flow rates i.e. variables affecting the efficiency of the extraction system was evaluated. It is ascertained that metal ions such as iron can be separated simultaneously from matrix in the presence of 0.012 mM ligand, 0.025% (w/v of CTAB to a test sample of 750 mL at pH 6.5. These ions can be eluted quantitatively with 6 mL of 1.0 mol L-1 HNO3 in methanol which lead to the enrichment factor of 125. The detection limits for analyte ions were in the range of 1.3-2.4 ng mL-1. The method has been successfully applied for determination of trace amounts of ions in various real samples.

  11. A Monte Carlo study on quantifying the amount of dose reduction by shielding the superficial organs of an Iranian 11-year-old boy

    Directory of Open Access Journals (Sweden)

    Parisa Akhlaghi

    2016-01-01

    Full Text Available A method for minimizing organ dose during computed tomography examinations is the use of shielding to protect superficial organs. There are some scientific reports that usage of shielding technique reduces the surface dose to patients with no appreciable loss in diagnostic quality. Therefore, in this Monte Carlo study based on the phantom of a 11-year-old Iranian boy, the effect of using an optimized shield on dose reduction to body organs was quantified. Based on the impact of shield on image quality, lead shields with thicknesses of 0.2 and 0.4 mm were considered for organs exposed directly and indirectly in the scan range, respectively. The results showed that there is 50%-62% reduction in amounts of dose for organs located fully or partly in the scan range at different tube voltages and modeling the true location of all organs in human anatomy, especially the ones located at the border of the scan, range affects the results up to 49%.

  12. Optimization of dispersive liquid-liquid microextraction for the selective determination of trace amounts of palladium by flame atomic absorption spectroscopy.

    Science.gov (United States)

    Kokya, Taher Ahmadzadeh; Farhadi, Khalil

    2009-09-30

    A new simple and reliable method for rapid and selective extraction and determination of the trace levels of Pd(2+) ion was developed by dispersive liquid-liquid microextraction preconcentration and flame atomic absorption spectrometry detection. In the proposed approach, thioridazine HCl (TRH) was used as a Pd(2+) ion selective complexing agent. The effective parameters on the extraction recovery were studied and optimized utilizing two decent optimization methods; factorial design and central composite design (CCD). Through factorial design the best efficiency of extraction acquired using ethanol and chloroform as dispersive and extraction solvents respectively. CCD optimization resulted in 1.50 mL of dispersive solvent; 0.15 mL of extraction solvent; 0.45 mg of TRH and 250 mg of potassium chloride salt per 5 mL of sample solution. Under the optimum conditions the calibration graph was linear over the range 100-2000 microgL(-1). The average relative standard deviation was 0.7% for five repeated determinations. The limit of detection was 90 microg L(-1). The average enrichment factor and recovery reached 45.7% and 74.2% respectively. The method was successfully applied to the determination of trace amounts of palladium in the real water samples.

  13. Graphene for Preconcentration of Trace Amounts of Ni in Water and Paraffin-Embedded Tissues from Liver Loggerhead Turtles Specimens Prior to flame Atomic Absorption Spectrometry

    Directory of Open Access Journals (Sweden)

    Hanie Arbabi Rashid

    2014-03-01

    Full Text Available A new sensitive and simple method was developed for the preconcentration of trace amounts of Ni using 1-(2-pyridylazo-2-naphthol (PAN as chelating reagent prior to its determination by flame atomic absorption spectrometry. The proposed method is based on the uti- lization of a column packed with graphene as sorbent. Several effective parameters on the extraction and complex formation were selected and optimized. Under optimum conditions, the calibration graph was linear in the concentration range of 5.0–240.0 µg L-1 with a detection limit of 0.36 µg L-1. The relative standard deviation for ten replicate measurements of 20.0 and 100.0 µg L-1 of Ni were 3.45 and 3.18%, respectively. Comparative studies showed that graphene is superior to other adsorbents including C18 silica, graphitic carbon, and single- and multi-walled carbon nanotubes for the extraction of Ni. In the present study, we report the application of preconcentration techniques still continues increasingly for trace metal determinations by flame atomic absorption spectrometry (FAAS for quantification of Ni in Formalin-fixed paraffin-embedded (FFPE tissues from Liver loggerhead turtles. The proposed method was successfully applied in the analysis of four real environmental water samples. Good spiked recoveries over the range of 95.8–102.6% were obtained.

  14. Dispersive liquid-liquid microextraction for the simultaneous separation of trace amounts of zinc and cadmium ions in water samples prior to flame atomic absorption spectrometry determination

    Directory of Open Access Journals (Sweden)

    Sayed Zia Mohammadi

    2012-01-01

    Full Text Available In the proposed method, carbon tetrachloride and ethanol were used as extraction and dispersive solvents. Several factors that may be affected on the extraction process, such as extraction solvent, disperser solvent, the volume of extraction and disperser solvent, pH of the aqueous solution and extraction time were optimized. Under the optimal conditions, linearity was maintained between 1.0 ng mL-1 to 1.5 mg mL-1 for zinc and 1.0 ng mL-1 to 0.4 mg mL-1 for cadmium. The proposed method has been applied for determination of trace amount of zinc and cadmium in standard and water samples with satisfactory results.

  15. Selective cloud point extraction and preconcentration of trace amounts of silver as a dithizone complex prior to flame atomic absorption spectrometric determination

    Energy Technology Data Exchange (ETDEWEB)

    Manzoori, Jamshid L.; Karim-Nezhad, Ghasem

    2003-05-19

    Dithizone (diphenylthiocarbazone) was used as a complexing agent in cloud point extraction for the first time and applied for selective preconcentration of trace amounts of silver. The analyte in the initial aqueous solution was acidified with sulfuric acid (pH<1) and Triton X-114 was added as a surfactant. After phase separation, based on the cloud point separation of the mixture, the surfactant rich phase was diluted with tetrahydrofuran (THF) and the analyte determined in the enriched solution by flame atomic absorption spectrometry. After optimization of the complexation and extraction conditions, a preconcentration factor of 43 was obtained for only 10 ml of sample. The analytical curve was linear in the range of 3-200 ng ml{sup -1} and the limit of detection was 0.56 ng ml{sup -1}. The proposed method was applied to the determination of silver in water samples.

  16. Selective Flow Injection Analysis of Ultra-trace Amounts of Cr(VI), Preconcentration of It by Solvent Extraction, and Determination by Electrothermal Atomic Absorption Spectrometry (ETAAS)

    DEFF Research Database (Denmark)

    Nielsen, Steffen; Sturup, Stefan; Spliid, Henrik

    1999-01-01

    A rapid, robust, sensitive and selective time-based flow injection (FI) on-line solvent extraction system interfaced with electrothermal atomic absorption spectrometry (ETAAS) is described for analyzing ultra-trace amounts of Cr(VI). The sample is initially mixed on-line with isobutyl methyl ketone......(VI) was achieved after preconcentration for 99 s at a sample flow rate of 5.5 ml min-1, as compared to direct introduction of 55 mul of sample, yielding a detection limit (3sigma) of 3.3 ng l-1. The sampling frequency was 24.2 samples h-1. The proposed method was successfully evaluated by analyzing a NIST Cr...

  17. Determination of Trace Amounts of Gold in Soil Sample Using Plastic Foam Enrichment-ICP-MS Method%泡塑富集ICP-MS测定土壤中痕量金

    Institute of Scientific and Technical Information of China (English)

    余波

    2008-01-01

    The aim of this study is to determine the trace amount of gold in soil sample using plastic foam enrichment-ICP-MS method. The national standard reference materials including GAu-2,GAu-10,GAu-11 and GAu-13 were used for parallel determination by ICPMS. The results showed that the method performed well in detection limit, precision and accuracy, indicating that the plastic foam enrichment-ICP-MS method could be used to determine the trace amounts of gold in soil sample.

  18. Ionic liquid ultrasound assisted dispersive liquid-liquid microextraction method for preconcentration of trace amounts of rhodium prior to flame atomic absorption spectrometry determination

    Energy Technology Data Exchange (ETDEWEB)

    Molaakbari, Elaheh [Chemistry Department, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Young Research Society, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Mostafavi, Ali, E-mail: mostafavi.ali@gmail.com [Chemistry Department, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Afzali, Daryoush [Environment and Nanochemistry Department, Research Institute of Environmental Science, International Center for Science, High Technology and Environmental Science, Kerman (Iran, Islamic Republic of); Mineral Industries Research Center, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of)

    2011-01-30

    In this article, we consider ionic liquid based ultrasound-assisted dispersive liquid-liquid microextraction of trace amounts of rhodium from aqueous samples and show that this is a fast and reliable sample pre-treatment for the determination of rhodium ions by flame atomic absorption spectrometry. The Rh(III) was transferred into its complex with 2-(5-bromo-2-pyridylazo)-5-diethylamino phenol as a chelating agent, and an ultrasonic bath with the ionic liquid, 1-octyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide at room temperature was used to extract the analyte. The centrifuged rhodium complex was then enriched in the form of ionic liquid droplets and prior to its analysis by flame atomic absorption spectrometry, 300 {mu}L ethanol was added to the ionic liquid-rich phase. Finally, the influence of various parameters on the recovery of Rh(III) was optimized. Under optimum conditions, the calibration graph was linear in the range of 4.0-500.0 ng mL{sup -1}, the detection limit was 0.37 ng mL{sup -1} (3S{sub b}/m, n = 7) and the relative standard deviation was {+-}1.63% (n = 7, C = 200 ng mL{sup -1}). The results show that ionic liquid based ultrasound assisted dispersive liquid-liquid microextraction, combined with flame atomic absorption spectrometry, is a rapid, simple, sensitive and efficient analytical method for the separation and determination of trace amounts of Rh(III) ions with minimum organic solvent consumption.

  19. Application of Cold-Induced Aggregation Microextraction Based on Ionic Liquid for Determination of Trace Amount of Cadmium and Lead in Powder Milk Samples

    Directory of Open Access Journals (Sweden)

    Mostafa Delavar

    2014-06-01

    Full Text Available Background: cold-induced aggregation micro extraction based (CIAME based on ionic liquid was used as a rapid and simple method for determination trace amounts of cadmium and lead in milk powder by analysis with flame atomic absorption spectrometry (FAAS. Methods: Sample solution containing of Cd2+ and Pb2+ in dynamic range, phosphate buffer (pH = 9, 3 ml, diethyl dithiocarbamate (complexing agent, Triton X-100, NaPF6 ,[HMIM][PF6] (extraction solvent were transferred into conical bottom glass tube. Sample was kept in a thermostated bath and then ice bath; a cloudy solution was formed. Two phases separated by centrifugation. After removing of aqueous phase, IL-phase was dissolved in methanol and diluted was injected to the FAAS by microsampler introduction. Results: ILs, containing imidazoliumcation and hexafluoro phosphate anion, [HMIM][PF6](70mg, 200 mg NaPF6 ,0.01 mol.L-1 DDTC, 0.015% of Triton X-100 obtained, pH 9 and centrifuge time; 5 min (4000 rmp was chosen. Detection limit were obtained 0.12 µgL-1, 1.61µgL-1, RSD 0.95%, 2.2% and enrichment factor of 70, 67 for Cd and Pb, respectively. Conclusion: CIAME allows determination of cadmium and lead in real samples in a simple, rapid and safe method with only a small amount of ionic liquid was used. In comparison with the organic solvent extraction, CIAME is much safer and the determination of species in high ionic strength samples is possible.

  20. Flotation-separation and ICP-AES determination of ultra trace amounts of copper, cadmium, nickel and cobalt using 2-aminocyclopentene-1-dithiocarboxylic acid.

    Science.gov (United States)

    Shamsipur, Mojtaba; Hashemi, Omid Reza; Safavi, Afsaneh

    2005-09-01

    A rapid flotation method for separation and enrichment of ultra trace amounts of copper(II), cadmium(II), nickel(II) and cobalt(II) ions from water samples is established. At pH 6.5 and with sodium dodecylsulfate used as a foaming reagent, Cu2+, Cd2+, Ni2+ and Co2+ were separated simultaneously with 2-aminocyclopentene-1-dithiocarboxylic acid (ACDA) added to 1 l of aqueous solution. The proposed procedure of preconcentration is applied prior to the determination of these four analytes using inductivity coupled plasma-atomic emission spectrometry (ICP-AES). The effects of pH, concentration of ACDA, applicability of different surfactants and foreign ions on the separation efficiency were investigated. The preconcentration factor of the method is 1000 and the detection limits of copper(II), cadmium(II), nickel(II) and cobalt(II) ions are 0.078, 0.075, 0.072 and 0.080 ng ml(-1), respectively.

  1. Preparation of Modified Magnetic Nanocomposites Dithiooxamide/Fe3O4 for Preconcentration and Determination of Trace Amounts of Cobalt Ions in Food and Natural Water Samples

    Directory of Open Access Journals (Sweden)

    Ali Mirabi

    2016-09-01

    Full Text Available The first study on the high efficiency of nanometer-sized magnetic nanoparticles (Fe3O4 coated with sodium dodecyl sulfate (SDS and dithiooxamide as a new sorbent solid phase extraction has been reported. Modified magnetic nanicomposites was used to preconcentrate and separate Co (II ions in food and environmental water samples. Magnetic nanoparticles were prepared by chemical precipitation of Fe (II and Fe (III salts from aqueous solution by ammonia solution. These magnetic nanoparticles and nanocomposites were characterized by scanning electron microscopy (SEM, transmission electron microscopy (TEM, thermo gravimetric analysis (TGA and elemental analysis CHNS. A micro sample introduction system was employed for the nebulization micro-volume of diluted solution into flame atomic absorption spectrometry (FAAS. The extraction conditions were optimized by selecting the appropriate extraction parameters including the amount of nanosorbent, pH value, volume of dithiooxamide and condition of eluting solution. The detection limit of this method for Co (II ions was 1.21 ng ml-1 and the R.S.D. was 0.9% (n=6. The advantages of this new method include rapidity, easy preparation of nanosorbents and a high preconcentration factor. The proposed method has been applied to the determination of Co (II ions at trace levels in real samples such as, kiwi, orange, cucumber, apple, green pepper, honey, potato, tap water, river water and sea water with satisfactory results.

  2. An on-line spectrophotometric determination of trace amounts of thiourea in tap water, orange juice, and orange peel samples using multi-channel flow injection analysis.

    Science.gov (United States)

    Arab Chamjangali, M; Goudarzi, N; Ghochani Moghadam, A; Amin, A H

    2015-01-01

    In this work, a flow injection analysis (FIA) method was introduced for the determination of trace amounts of thiourea in tap water. This method is based upon the inhibition effect of thiourea on the reaction between meta-cresol purple (MCP) and potassium bromate catalyzed by bromide ions in a sulfuric acid medium. In the presence of thiourea, an induction period appears in the reaction system, and as a result, the absorbance of MCP increases at 525 nm in the FIA manifold. The chemical and FIA variables are studied and optimized using the univariate and Simplex optimization methods. Under the optimum conditions, thiourea can be determined in the range of 0.100-13.0 μg mL(-1). The limit of detection (3σ) for thiourea was found to be 0.0310 μg mL(-1). The relative standard deviations (RSDs) for six replicate determinations of 0.500, 5.00, and 12.0 μg mL(-1) of thiourea were 4.0%, 1.8%, and 1.2%, respectively. The proposed method was also applied for the determination of thiourea in orange juice and orange peel samples with recoveries in the range of 98.0-101%. The analytical speed of the method was calculated to be about 120 sample per hour.

  3. Determination of Trace Amounts of Gold in Environmental Samples by Adsorptive Stripping Voltammetry of Its Complex with Rhodamine Using Osc-Pls

    Directory of Open Access Journals (Sweden)

    A. Akrami

    2012-11-01

    Full Text Available The multivariate calibration method was applied for the determination of trace amounts of gold based on a hanging mercury drop electrode (HMDE in the presence of rhodanine, followed by reduction of adsorbed gold by voltammetric scan using differential pulse modulation The optimum experimental conditions are: rhodanine concentration of 0.20 mg mL-1, pH 5.0, accumulation potential of -600 mV versus Ag/AgCl, accumulation time of 100 sec, scan rate of 30 mV s-1 and pulse height of 100 mV. The calibration matrix for partial least squares (PLS regression was designed with 9 samples. Orthogonal signal correction (OSC is a preprocessing technique used for removing the information unrelated to the target variables based on constrained principal component analysis. OSC is a suitable preprocessing method for PLS calibration without loss of prediction capacity using electrochemical method. The RMSEP for gold determination with PLS and OSC-PLS were 8.51 and 1.94, respectively. This procedure allows the determination of gold in synthetic and real samples with good reliability of the determination. 

  4. Amberlite XAD-4 Impregnated With a New Pentadentate Schiff base: a Chelating Collector for Separation and Preconcentration of Trace Amounts of Gallium (III) and Indium (III).

    Science.gov (United States)

    Saberyan, Kamal; Zolfonoun, Ehsan; Shamsipur, Mojtaba; Salavati-Niasari, Masoud

    2010-03-01

    A new solid-phase extraction method for separation and preconcentration of trace amounts of Ga(III) and In(III) in biological and water samples is proposed. The procedure is based on the adsorption of Ga(III) and In(III) ions on a column of Amberlite XAD-4 resin loaded with newly-synthesized pentadentate naphthol-derivative Schiff base 1-[(6-[(E)-1-(2-hydroxy-1-naphthyl)methylidene]amino-2-pyridyl)imino]methyl-2-naphthol (HMPN) prior to their determination by flame atomic absorption spectrometry (FAAS). The optimum pH values for quantitative sorption of Ga(III) and In(III) are 4.5-6.0 and 4.5-8.0, respectively, and their desorptions can be achieved by using 5 mL of 0.5 M HNO3. The sorption capacities of the resin for Ga(III) and In(III) were 1.27 and 1.45 mg g-1, respectively. The enrichment factor for preconcentration of Ga(III) and In(III) was found to be 200. The precision of the method, evaluated as the relative standard deviation obtained by analyzing a series of ten replicates, was below 3% for both elements. The proposed procedure was applied to the analysis of synthetic seawater, natural waters, wastewater and human blood serum using flame AAS.

  5. SPE coupled with dispersive liquid-liquid microextraction followed by GC with flame ionization detection for the determination of ultra-trace amounts of benzodiazepines.

    Science.gov (United States)

    Ghobadi, Masoomeh; Yamini, Yadollah; Ebrahimpour, Behnam

    2014-02-01

    SPE combined with dispersive liquid-liquid microextration was used for the extraction of ultra-trace amounts of benzodiazepines (BZPs) including, diazepam, midazolam, and alprazolam, from ultra-pure water, tap water, fruit juices, and urine samples. The analytes were adsorbed from large volume samples (60 mL) onto octadecyl silica SPE columns. After the elution of the desired compounds from sorbents with 2.0 mL acetone, 0.5 mL of eluent containing 40.0 μL chloroform was injected rapidly into 4.5 mL pure water. After extraction and centrifugation, 2 μL of the sedimented phase was injected into a GC equipped with a flame ionization detector. Several parameters affecting this process were investigated and optimized. Under the optimal conditions, LODs ranged from 0.02 to 0.05 μg/L, a linear dynamic range of 0.1-100 μg/L and relative SDs in the range of 4.4-10.7% were attained. Very high preconcentration factors ranging from 3895-7222 were achieved. The applicability of the method for the extraction of BZPs from different types of complicated matrices, such as tap water, fruit juices, and urine samples, was studied. The obtained results reveal that the proposed method is a good technique for the extraction and determination of BZPs in complex matrices.

  6. Developing a qPCR method to quantify AhR-PCP-DNA complex for detection of environmental trace-level PCP.

    Science.gov (United States)

    Zhao, Xiaoxiang; Pang, Xiaoqian; Chaisuwan, Nuanapa

    2011-07-01

    Pentachlorophenol (PCP), a widely-used aseptic or biocide, is known as an environmental toxicant involved in endocrine disruption even at a trace level. In order to reliably and efficiently quantify environmental trace-quantity PCP, this study developed a novel PCP detection method using the aryl hydrocarbon receptor (AhR) and fluorescence quantitative PCR (qPCR). DNA probe with AhR binding sites was synthesized by PCR before added into AhR-PCP complex. After AhR-PCP-DNA complex was digested with exonuclease, copy number of DNA probe was determined using fluorescence qPCR. To calculate PCP concentration in samples, a standard curve (PCP concentration versus Ct value) was constructed and the detection range was 10(-13) to 10(-9) M. PCP detection limit was 0.0089 ppt for the AhR-PCP-DNA complex assay and 8.8780 ppm for high performance liquid chromatography, demonstrating that the method developed in this study is more sensitive. These results suggest that AhR-PCP-DNA complex method may be successfully applicable in detection and quantification of environmental trace-level PCP.

  7. Development of a dual test procedure for DNA typing and methamphetamine detection using a trace amount of stimulant-containing blood.

    Science.gov (United States)

    Irii, Toshiaki; Maebashi, Kyoko; Fukui, Kenji; Sohma, Ryoko; Matsumoto, Sari; Takasu, Shojiro; Iwadate, Kimiharu

    2016-05-01

    Investigation of drug-related crimes, such as violation of the Stimulant Drug Control Law, requires identifying the used drug (mainly stimulant drugs, methamphetamine hydrochloride) from a drug solution and the DNA type of the drug user from a trace of blood left in the syringe used to inject the drug. In current standard test procedures, DNA typing and methamphetamine detection are performed as independent tests that use two separate portions of a precious sample. The sample can be entirely used up by either analysis. Therefore, we developed a new procedure involving partial lysis of a stimulant-containing blood sample followed by separation of the lysate into a precipitate for DNA typing and a liquid-phase fraction for methamphetamine detection. The method enables these two tests to be run in parallel using a single portion of sample. Samples were prepared by adding methamphetamine hydrochloride water solution to blood. Samples were lysed with Proteinase K in PBS at 56°C for 20min, cooled at -20°C after adding methanol, and then centrifuged at 15,000rpm. Based on the biopolymer-precipitating ability of alcohol, the precipitate was used for DNA typing and the liquid-phase fraction for methamphetamine detection. For DNA typing, the precipitate was dissolved and DNA was extracted, quantified, and subjected to STR analysis using the AmpFℓSTR® Identifiler® Plus PCR Amplification Kit. For methamphetamine detection, the liquid-phase fraction was evaporated with N2 gas after adding 20μL acetic acid and passed through an extraction column; the substances captured in the column were eluted with a solvent, derivatized, and quantitatively detected using gas chromatograph/mass spectrometry. This method was simple and could be completed in approximately 2h. Both DNA typing and methamphetamine detection were possible, which suggests that this method may be valuable for use in criminal investigations.

  8. Reagent optimization for on-line simultaneous polarographic determination of trace amounts of Cu2+, Cd2+ and Co2+ in the presence of anextremely large excess of Zn2+

    Institute of Scientific and Technical Information of China (English)

    王国伟; 阳春华; 朱红求; 李勇刚; 桂卫华

    2016-01-01

    Reagents are optimized for the simultaneous determination of trace amounts of Cu2+, Cd2+ and Co2+ in zinc sulfate solution, which contains an extremely large excess of Zn2+. First, the reagents and their doses for the experiment are selected according to the characteristics of the zinc sulfate solution. Then, the reagent doses are optimized by analyzing the influence of reagent dose on the polarographic parameters (i.e. half-wave potentialE1/2 and limiting diffusion current Ip). Finally, the optimization results are verified by simultaneously determining trace amounts of Cu2+, Cd2+ and Co2+ in the presence of an extremely large excess of Zn2+. The determination results indicate that the optimized reagents exhibit wide linearity, low detection limits, high accuracy and good precision for the simultaneous determination of trace amounts of Cu2+, Cd2+ and Co2+ in the presence of an extremely large excess of Zn2+.

  9. Unusually Flexible Indium(III) Metal-Organic Polyhedra Materials for Detecting Trace Amounts of Water in Organic Solvents and High Proton Conductivity.

    Science.gov (United States)

    Du, Xi; Fan, Ruiqing; Qiang, Liangsheng; Song, Yang; Xing, Kai; Chen, Wei; Wang, Ping; Yang, Yulin

    2017-03-20

    Humidity-induced single-crystal transformation was observed in the indium metal-organic polyhedra [In2(TCPB)2]·2H2O (In1), where H3TCPB is 1,3,5-tri(4-carboxyphenoxy)benzene. When the humidity is above 58% relative humidity (RH) at room temperature, the neutral compound In1 could be successfully converted into the positively charged compound In1-H along with the color change from yellow to deep red, which also undergoes a reversible transformation into In1 driven by thermal dehydration. Notably, the color of In1 takes only 5 min to change under 58% RH at room temperature, which is much quicker than common desiccant bluestone. As the water content is increased from 0.0% to 0.2% in acetonitrile solvent, compound In1 exhibits rapid detection of trace amounts of water through turn-off luminescence sensing mechanism with a low detection limit of 2.95 × 10(-4)%. Because of the formation of extensive hydrogen-bonding network between the metal-organic polyhedra (MOPs) and surrounding guest OH(-) ions, compound In1-H, along with isostructural Ga1-H, displays excellent proton conductivity up to 2.84 × 10(-4) and 2.26 × 10(-4) S cm(-1) at 298 K and 98% RH, respectively. Furthermore, the activation energies are found to be 0.28 eV for In1-H and 0.34 eV for Ga1-H. This method of incorporation of OH(-) ions to obtain high proton conductivity MOPs with low activation energy demonstrates the advantage of OH(-) ion conduction in the solid-state materials.

  10. A rapid method for the detection of foodborne pathogens by extraction of a trace amount of DNA from raw milk based on label-free amino-modified silica-coated magnetic nanoparticles and polymerase chain reaction

    Science.gov (United States)

    A method based on amino-modified silica-coated magnetic nanoparticles (ASMNPs) and polymerase chain reaction (PCR) was developed to rapidly and sensitively detect foodborne pathogens in raw milk. After optimizing parameters such as pH, temperature, and time, a trace amount of genomic DNA of pathogen...

  11. Self-Assembled Templates of Aromatic Pentapeptides for Synthesis of CdS Quantum-Dots to Detect the Trace Amounts of Hg(2+) in Aqueous Solutions.

    Science.gov (United States)

    Meng, Min; Dou, Yingying; Xu, Wenlong; Hao, Jingcheng

    2016-05-01

    Molecular self-assembly has become a popular tool to prepare nanomaterials with potential applications, such as ion-responsive detection of Hg(2+) in aqueous solutions. In this study, FFACD aromatic pentapeptides, whose N-terminuses were protected by carboxyl (Ac-FFACD) or a 9-fluorenylmethoxycarbonyl group (Fmoc-FFACD), were chosen as building blocks to produce nanostructures in solutions. Based on the preliminary determination of the critical aggregation concentration (CAC) of Ac-FFACD and Fmoc-FFACD aromatic pentapeptides in water, the order of magnitude of which is 10(-5) mol·L(-1), self-assembled spiral and networked nanowires can be easily obtained over a range of concentrations. These nanowires were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The self-assembled spiral and networked nanowires were designed to be used as templates for preparing CdS quantum dots (QDs) in-situ at room temperature. The peptide-functionalized, nanowire-encapsulated CdS QDs can be used for rapid, sensitive, and selective detection of trace amounts of mercuric ions (Hg(2+)) in aqueous solutions. This method enables rapid, linear detection (the linear correlation coefficients are 0.9972 of ΔF = 257.09 + 3.58 cHg(2+) for Ac-FFACD and 0.9994 of ΔF = 48.13 + 32.96 cHg(2+) for Fmoc-FFACD) with the Hg(2+) limit of detection at 300.85 ng·L(-1) and 32.09 ng·L(-1) for Ac-FFACD and Fmoc-FFACD, respectively. The supramolecular, self-assembled nanowires, fabricated from the two aromatic pentapeptides and having encapsulated QDs, exhibit superior properties attributable to the large loading capacity and the coordination sites of these peptides with Hg(2+). These structures can serve as novel Hg(2+) sensors and have possible applications for detection of various targets in scientific and engineering systems.

  12. A comparison between determination of trace amounts of sulfide in the presence and absence of micelle particles in natural waters (Qazvin, Iran): a kinetic spectrophotometric approach.

    Science.gov (United States)

    Alizadeh, Nina; Mahjoub, Mohammad

    2015-05-01

    A new sensitive kinetic spectrophotometric method described for the determination of trace amounts of sulfides based on the addition reaction of sulfide ions with malachite green has been investigated in aqueous and micellar media at 25 °C. The variables affecting the rate of the reaction were investigated, and the optimum conditions were established. Under the optimum experimental conditions, decreases in the absorbance of malachite green at 615 nm in the absence and 630 nm in the presence of micelle particles, their λ max, were proportional to the concentrations of sulfide ions at the first 15 and 25 s from initiation of the reaction. The working curve was linear over the concentration range 50-1200 ng mL(-1) of sulfide ions with a fixed time method at the first 15 and 25 s from initiation of the reaction in aqueous medium and 25-1750 ng mL(-1) with a fixed time method at the first 15 s and 25-1500 ng mL(-1) for primitive 25 s in micellar medium. For the proposed kinetic method, the experimental and theoretical limit of detection (LOD) and limit of quantification (LOQ) in the presence and absence of micelle particles were obtained and tabulated at Δt = 15 and 25 s. The effective range concentration was achieved from the plot of Ringbom in both media and reported. Different surfactants, such as nonionic surfactant (Triton-X100), anionic surfactant sodium dodecyl sulfate (SDS), and cationic surfactant cetyltrimethylammonium bromide (CTAB) and cetylpyridinium chloride (CPC), were investigated and Triton X-100 selected as a suitable surfactant. To valuable vision into the reaction pathways, pseudo-first-order condition was applied and different kinetic parameters like ΔG (≠), ΔE (≠), ΔS (≠), and ΔH (≠) computed. The 2:1 stoichiometry of malachite green to sulfide ions was indicated by the results of mole ratio and Job's method of continuous variation. The effect of different environments on the interfering of various ions on sulfide

  13. A methodology for quantifying trace elements in the exoskeletons of Florida stone crab (Menippe mercenaria) larvae using inductively coupled plasma optical emission spectrometry (ICP–OES)

    Science.gov (United States)

    Gravinese, Philip M.; Flannery, Jennifer A.; Toth, Lauren T.

    2016-11-23

    The larvae of the Florida stone crab, Menippe mercenaria, migrate through a variety of habitats as they develop and, therefore, experience a broad range of environmental conditions through ontogeny. Environmental variability experienced by the larvae may result in distinct elemental signatures within the exoskeletons, which could provide a tool for tracking the environmental history of larval stone crab populations. A method was developed to examine trace-element ratios, specifically magnesium-to-calcium (Mg/Ca) and strontium-to-calcium (Sr/Ca) ratios, in the exoskeletons of M. mercenaria larvae. Two developmental stages of stone crab larvae were analyzed—stage III and stage V. Specimens were reared in a laboratory environment under stable conditions to quantify the average ratios of Mg/Ca and Sr/Ca of larval stone crab exoskeletons and to determine if the ratios differed through ontogeny. The elemental compositions (Ca, Mg, and Sr) in samples of stage III larvae (n = 50 per sample) from 11 different broods (mean Sr/Ca = 5.916 ± 0.161 millimole per mole [mmol mol−1]; mean Mg/Ca = 218.275 ± 59.957 mmol mol−1) and stage V larvae (n = 10 per sample) from 12 different broods (mean Sr/Ca = 6.110 ± 0.300 mmol mol−1; mean Mg/Ca = 267.081 ± 67.211 mmol mol–1) were measured using inductively coupled plasma optical emission spectrometry (ICP–OES). The ratio of Sr/Ca significantly increased from stage III to stage V larvae, suggesting an ontogenic shift in Sr/Ca ratios between larval stages. The ratio of Mg/Ca did not change significantly between larval stages, but variability among broods was high. The method used to examine the trace-element ratios provided robust, highly reproducible estimates of Sr/Ca and Mg/Ca ratios in the larvae of M. mercenaria, demonstrating that ICP–OES can be used to determine the trace-element composition of chitinous organisms like the Florida stone crab.

  14. Determination of trace amounts of selenium in minerals and rocks by flame less atomic-absorption spectrometry; Determinacion de selinio en minerales y rocas por espectrometria de absorcion atomica

    Energy Technology Data Exchange (ETDEWEB)

    Alduan, F. A.; Capdevilla, C.

    1980-07-01

    The determination of trace amounts of selenium In silicate rocks and feldspar by solvent extraction and graphite furnace atomic-absorption spectrometry has been stu- died. Sodium diethyl-ditio carbamate and ammonium pyrrolidine dithiocarbamate have been tried as chelating agents. The best results are achieved when selenium is extracted Into carbon tetrachloride as the sodium diethyldithiocarbamate complex. The method allows to detect 0,75 ppm of selenium in the sample. Recoveries are about 100%. (Author) 7 refs.

  15. Trace amounts of water-induced distinct growth behaviors of NiO nanostructures on graphene in CO2-expanded ethanol and their applications in lithium-ion batteries.

    Science.gov (United States)

    Zhuo, Linhai; Wu, Yingqiang; Zhou, Wei; Wang, Lingyan; Yu, Yancun; Zhang, Xinbo; Zhao, Fengyu

    2013-08-14

    In this work, we have developed a new method to grow NiO nanomaterials on the surface of graphene nanosheets (GNSs). The morphologies of NiO nanomaterials grown on GNSs could be tailored by trace amounts of water introduced into the mixed solvents of CO2-expanded ethanol (CE). Small and uniform Ni-salt nanoparticles (Ni-salt-NPs) were grown on the surface of graphene oxide (GO) through the decomposition of nickel nitrate directly in CE. However, when trace amounts of water were introduced into the mixed solvents, Ni-salt nanoflakes arrays (Ni-salt-NFAs) were grown on the surface of GO with almost perpendicular direction. After thermal treatment in N2 atmosphere, these Ni-salt @GO composites were converted to NiO@GNSs composites. The forming mechanisms of the NiO-NPs@GNSs and NiO-NFAs@GNSs were discussed by series comparative experiments. The presence of the trace amounts of water affected the chemical composition and structure of the precursors formed in CE and the growth behaviors on the surface of GNSs. When used as anode materials for lithium-ion batteries, the NiO-NPs@GNSs composite exhibited better cycle and rate performance compared with the NiO-NFAs@GNSs.

  16. Trace amounts of rare earth elements in high purity samarium oxide by sector field inductively coupled plasma mass spectrometry after separation by HPLC

    Energy Technology Data Exchange (ETDEWEB)

    Pedreira, W.R. [Instituto de Geociencias, Universidade de Brasilia (UnB), 70910-900 Brasilia, DF (Brazil) and Fundacao Jorge Duprat Figueiredo de Seguranca e Medicina do Trabalho (FUNDACENTRO), 05409-002 Sao Paulo, SP (Brazil)]. E-mail: walter.pedreira@fundacentro.gov.br; Queiroz, C.A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), 05508-900 Sao Paulo, SP (Brazil); Abrao, A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), 05508-900 Sao Paulo, SP (Brazil); Rocha, S.M. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), 05508-900 Sao Paulo, SP (Brazil); Vasconcellos, M.E. de [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), 05508-900 Sao Paulo, SP (Brazil); Boaventura, G.R. [Instituto de Geociencias, Universidade de Brasilia (UnB), 70910-900 Brasilia, DF (Brazil); Pimentel, M.M. [Instituto de Geociencias, Universidade de Brasilia (UnB), 70910-900 Brasilia, DF (Brazil)

    2006-07-20

    Today there is an increasing need for high purity rare earth compounds in various fields, the optical, the electronics, the ceramic, the nuclear and geochemistry. Samarium oxide has special uses in glass, phosphors, lasers and thermoelectric devices. Calcium chloride crystals treated with samarium have been employed in lasers, which produce light beams intense enough to burn metal. In general, the inductively coupled plasma mass spectrometry (ICP-MS) presents some advantages for trace element analysis, due to high sensitivity and resolution, when compared with other analytical techniques such as ICP optical emission spectrometry (ICP-OES). In this work, sector field inductively coupled plasma mass spectrometry was used. Sixteen elements (Sc, Y and 14 lanthanides) were determined selectively with the ICP-MS system using a concentration gradient method. The detection limits with the ICP-MS system were about 0.2 (La) pg mL{sup -1} to 8 (Gd) pg mL{sup -1}. The %R.S.D. of the methods varying between 0.9 and 1.5% for a set of five (n = 5) replicates was found for the IPEN's material and for the certificate reference sample. Determination of trace REEs in two high pure samarium oxides samples (IPEN and JMC) was performed. IPEN's material is highly pure (>99.99%) and was successfully analyzed without spectral interference (MO{sup +} and MOH{sup +})

  17. Preconcentration and separation of trace amount of heavy metal ions on bis(2-hydroxy acetophenone)ethylendiimine loaded on activated carbon.

    Science.gov (United States)

    Ghaedi, M; Shokrollahi, A; Kianfar, A H; Pourfarokhi, A; Khanjari, N; Mirsadeghi, A S; Soylak, M

    2009-03-15

    A sensitive and simple method for simultaneous preconcentration of trace heavy metal ions in some food samples has been reported. The method is based on the adsorption of Cr(3+), Fe(3+), Cu(2+), Ni(2+), Co(2+) and Zn(2+) on bis(2-hydroxy acetophenone)ethylendiimine (BHAPED) loaded on activated carbon (AC). The adsorbed metals on activated carbon were eluted using 2 mol L(-1) nitric acid in acetone. The influences of the analytical parameters including pH and sample volume were investigated. The effects of matrix ions on the recoveries of analyte ions were also investigated. The recoveries of analytes were generally higher than 94%. The method has been successfully applied for analysis of the metal contents in real samples including natural water samples.

  18. Solid phase extraction and determination of ultra trace amounts of copper(II) using octadecyl silica membrane disks modified by 11-hydroxynaphthacene-5,12-quinone and flame atomic absorption spectrometry.

    Science.gov (United States)

    Shamsipur, M; Avanes, A; Rofouei, M K; Sharghi, H; Aghapour, G

    2001-06-21

    A simple and selective method for rapid extraction and determination of trace amounts of copper(II) ions using octadecyl-bonded silica membrane disks modified with 11-hydroxynaphthacene-5,12-quinone and flame atomic absorption spectrometry is presented. Extraction efficiency and the influence of pH, flow rates, amount of ligand and type and least amount of stripping acid were evaluated. Maximum capacity of the membrane disks modified by 5 mg of the ligand was found to be 360 mug of Cu(2+) ion. The break through volume is larger than 2000 ml. The limit of detection of the proposed method is 0.2 ng ml(-1). The effects of various cationic interferences on the percent recovery of copper in binary mixtures were studied. The method was applied to the recovery of Cu(2+) ions from four different water samples and a synthetic sample.

  19. Determination of Trace Amount of Aluminium in Ironic Phosphate by Spectrophotometry%分光光度法测定磷酸铁中的微量铝

    Institute of Scientific and Technical Information of China (English)

    余长艳

    2015-01-01

    After separating most iron by high levels of sodium hydrate,using chromeazurol S as chro-mogenic reagent and using ascorbic acid to mask light ironic,in the acetic acid -sodium acetate buffer solu-tion,the trace amout of aluminium content in ironic phosphate was determined.This method was simple, with high accuracy.The labeled recovery was between 90.1% ~107.5%,The RSD was less than 6.8% .%采用分光光度法测定磷酸铁中微量铝。先通过强碱分离掉绝大部分铁后,再采用铬天青 S 作显色剂,用抗坏血酸掩蔽微量的铁,在乙酸-乙酸钠缓冲溶液中测定磷酸铁中微量的铝。该方法简便易行,准确度高,回收率在90.1%~107.5%之间,相对标准偏差小于6.8%。

  20. Determination of Trace Amounts of Cerium by Nagative Catalytic Kinetic Spectrophotometric%负催化动力学光度法测定痕量铈

    Institute of Scientific and Technical Information of China (English)

    汪效祖; 郭会明; 汤涛; 黄或

    2001-01-01

    在中性介质中,Ce(Ⅳ)对过氧化氢氧化结晶紫的反应有较强的负催化作用,据此建立了负催化动力学光度法测定痕量铈的方法。方法线性范围为1.9×10-4~2.0×10-3μg/mL,已用于人发和鸡毛中铈的测定。%A new negative catalytic kinetic spectrophotometric method fordetermination of trace cerium was proposal. The mehtod was based on the negative catalytic effect of cerium(Ⅳ) on the oxidation of crystal violet by hydrogen peroxide in a medium of pH 7.0. The linear range was found to be 1.9×10-4~2.0×10-3 μg/mL. It was applied to the determination of cerium in hair and feather with satisfactory results.

  1. SiO2-coated magnetic graphene oxide modified with polypyrrole-polythiophene: A novel and efficient nanocomposite for solid phase extraction of trace amounts of heavy metals.

    Science.gov (United States)

    Molaei, Karam; Bagheri, Hasan; Asgharinezhad, Ali Akbar; Ebrahimzadeh, Homeira; Shamsipur, Mojtaba

    2017-05-15

    The synthesis of a novel nanocomposite comprised of SiO2-coated magnetic graphene oxide modified with a pyrrole-thiophene (mGO/SiO2@coPPy-Th) copolymer is reported in the present work. The nanocomposite was applied for the fast magnetic solid phase extraction (MSPE) of trace levels of copper, lead, chromium, zinc and cadmium from water and agricultural samples. The nanocomposite was prepared in three steps: (1) decoration of graphene oxide sheets with magnetite nanoparticles thorough a facile one-step chemical reaction strategy; (2) chemical grafting by a silica layer to obtain high stability in acidic solutions; and (3) surface modification by coPPy-Th via simultaneous oxidation polymerization of pyrrole and thiophene in the presence of mGO/SiO2 composite. The nanocomposite was subsequently characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD) and vibrating sample magnetometry (VSM) techniques. Several important experimental variables that could affect MSPE performance, including the pH of the sample, sorption time, sorbent dosage, eluent type and its concentration, eluent volume and elution time, were investigated and optimized. Under optimal conditions, the limits of detection for the target heavy metals ranged from 0.15 to 0.65μgL(-1). The maximum sorption capacity of the mGO/SiO2@coPPy-Th nanocomposite was 201, 230, 125, 98 and 80mgg(-1) for Cu(II), Pb(II), Zn(II), Cr(III) and Cd(II), respectively. Finally, the feasibility of the proposed method was investigated for the extraction and determination of the target metals from real matrices.

  2. Determination of trace amount of cadmium using dispersive liquid-liquid microextraction-slotted quartz tube-flame atomic absorption spectrometry

    Science.gov (United States)

    Fırat, Merve; Bakırdere, Sezgin; Fındıkoğlu, Maral Selin; Kafa, Emine Betül; Yazıcı, Elif; Yolcu, Melda; Büyükpınar, Çağdaş; Chormey, Dotse Selali; Sel, Sabriye; Turak, Fatma

    2017-03-01

    This study was performed to develop a sensitive analytical method for the determination of cadmium by slotted quartz tube-flame atomic absorption spectrometry (SQT-FAAS) after dispersive liquid-liquid microextraction (DLLME). The parameters affecting the cadmium complex formation and its extraction output were optimized to obtain high extraction efficiency. These included the pH and amount of the buffer solution, and the concentration of the ligand. The DLLME method was comprehensively optimized based on the type and amount of extraction solvent, dispersive solvent and salt. The type and period of mixing needed for a more effective extraction was also investigated. In order to further improve the sensitivity for the determination of cadmium, the flame atomic absorption spectrometry was fitted with a slotted quartz tube to increase the residence time of cadmium atoms in the pathway of incident light from a hollow cathode lamp. The limits of detection and quantitation (LOD and LOQ) for the FAAS were found to be 42 and 140 μg L- 1, respectively. Under the optimum conditions, LOD and LOQ of the FAAS after DLLME were calculated as 1.3 and 4.4 μg L- 1, respectively. Combining both optimized parameters of the DLLME and SQT-FAAS gave 0.5 and 1.5 μg L- 1 as LOD and LOQ, respectively. Accuracy of the method was also checked using a wastewater certified reference material (EU-L-2), and the result was in good agreement with the certified value.

  3. Separation/Preconcentration and Speciation Analysis of Trace Amounts of Arsenate and Arsenite in Water Samples Using Modified Magnetite Nanoparticles and Molybdenum Blue Method

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Karimi

    2014-01-01

    Full Text Available A new, simple, and fast method for the separation/preconcentration and speciation analysis of arsenate and arsenite ions using cetyltrimethyl ammonium bromide immobilized on alumina-coated magnetite nanoparticles (CTAB@ACMNPs followed by molybdenum blue method is proposed. The method is based on the adsorption of arsenate on CTAB@ACMNPs. Total arsenic in different samples was determined as As(V after oxidation of As(III to As(V using potassium permanganate. The arsenic concentration has been determined by UV-Visible spectrometric technique based on molybdenum blue method and amount of As(III was calculated by subtracting the concentration of As(V from total arsenic concentration. MNPs and ACMNPs were characterized by VSM, XRD, SEM, and FT-IR spectroscopy. Under the optimal experimental conditions, the preconcentration factor, detection limit, linear range, and relative standard deviation (RSD of arsenate were 175 (for 350 mL of sample solution, 0.028 μg mL−1, 0.090–4.0 μg mL−1, and 2.8% (for 2.0 μg mL−1, n=7, respectively. This method avoided the time-consuming column-passing process of loading large volume samples in traditional SPE through the rapid isolation of CTAB@ACMNPs with an adscititious magnet. The proposed method was successfully applied to the determination and speciation of arsenic in different water samples and suitable recoveries were obtained.

  4. Determination of Trace Amounts of Palladium in Water Samples by Graphite Furnace Atomic Absorption Spectrometry after Dispersive Liquid-Liquid Microextraction

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Jamali

    2013-01-01

    Full Text Available A simple, rapid, and powerful microextraction technique was used for determination of palladium (II ion in water samples using dispersive liquid-liquid microextraction (DLLME followed by graphite furnace atomic absorption spectrometry (GF AAS. The different variables affecting the complexation and extraction conditions such as extraction and disperser solvent type, extraction time, pH, and concentration of chelating agent were optimized. Under the optimum conditions, the calibration graph was linear in the ranges of 0.05–1 μg L−1 with detection limit of 0.02 μg L−1. The precision (RSD % for ten replicate determination at 0.2 μg L−1 of palladium was better than 3.5% and the enrichment factor 166.5 was obtained from only 5.0 mL of sample. Under the presence of foreign ions, no significant interference was observed. Finally, accuracy and application of the method were estimated by using test samples of natural waters spiked with different amounts of palladium.

  5. Solid-phase microextraction of ultra-trace amounts of tramadol from human urine by using a carbon nanotube/flower-shaped zinc oxide hollow fiber.

    Science.gov (United States)

    Abbasian, Maryam; Balali-Mood, Mahdi; Mozaffari, Sayed Ahmad; Amoli, Hossein Salar

    2016-11-01

    A new method is successfully developed for the separation and determination of a very low amount of tramadol in urine using functionalized multiwalled carbon nanotubes/flower-shaped zinc oxide before solid-phase microextraction combined with gas chromatography. Under ultrasonic agitation, a sol of multiwalled carbon nanotubes and flower-shaped zinc oxide were forced into and trapped within the pore structure of the polypropylene and the sol solution immobilized into the hollow fiber. Flower-shaped zinc oxide was synthesized and characterized by Fourier transform infrared spectroscopy. The morphology of the fabricated solid-phase microextraction surface was investigated by scanning electron microscopy and X-ray diffraction. The parameters affecting the extraction efficiencies were investigated and optimized. Under the optimized conditions, the method shows linearity in a wide range of 0.12-7680 ng/mL, and a low detection limit (S/N = 3) of 0.03 ng/mL. The precision of the method was determined and a relative standard deviation of 3.87% was obtained. This method was successfully applied for the separation and determination of tramadol in urine samples. The relative recovery percentage obtained for the spiked urine sample at 1000 ng/mL was 94.2%.

  6. Modified surface based on magnetic nanocomposite of dithiooxamide/Fe{sub 3}O{sub 4} as a sorbent for preconcentration and determination of trace amounts of copper

    Energy Technology Data Exchange (ETDEWEB)

    Mirabi, Ali, E-mail: mirabi2012@yahoo.com [Department of Chemistry, Qaemshahr Branch, Islamic Azad University, Qaemshahr (Iran, Islamic Republic of); Shokuhi Rad, Ali, E-mail: a.shokuhi@gmail.com [Department of Chemical Engineering, Qaemshahr Branch, Islamic Azad University, Qaemshahr (Iran, Islamic Republic of); Khodadad, Hadiseh [Department of Chemistry, Qaemshahr Branch, Islamic Azad University, Qaemshahr (Iran, Islamic Republic of)

    2015-09-01

    Magnetic nanocomposites surface (MNCS) which has anionic surfactant sodium dodecyl sulfate (SDS) coating and has undergone dithiooxamide treatment as the sorbent could be an easy and useful method to extract and make a pre-concentrated in detecting the copper ions before they are determined via the flame atomic absorption spectrometry (FAAS). The influences of the experimental parameters such as the pH of the sample, the type and concentration of the eluent, dithiooxamide concentration and volume, amount of sorbent and the interactions of ions with respect to the copper ion detection have been studied. The calibration graph was linear in the range of 2–600 ng ml{sup −1} with detection limit of 0.2 ng ml{sup −1}. Relative standard deviation (RSD) for 6 replicate measurements was 1.8%. This method of detection has been applied to the determination of Cu ions at levels in real samples such as wheat flour, tomatoes, potatoes, red beans, oat, tap water, river water and sea water with satisfactory results. - Highlights: • Fe{sub 3}O{sub 4} nano-magnetic improved by SDS/dithiooxamide. • It can be used in both the pre-concentration function and detecting of Cu ions. • This modified surface shows high adsorptive characteristics. • This procedure is relatively simple, fast and imposes less test analysis expenses.

  7. Trend overtime of total haemoglobin, iron metabolism and trace minerals in veal calves fed high amounts of two different solid feeds

    Directory of Open Access Journals (Sweden)

    Anna-Lisa Stefani

    2010-01-01

    Full Text Available Fifty Polish Friesian veal calves were administrated high amounts of two different solid feeds (maize grain and a mix diet containing 10% of straw and 8% of soy in addition to the traditional milk replacer diet. Compared to the mix diet, maize grain had a lower content of iron, copper and zinc and a minor fibre level. Effects of the two diets on calves’ blood haemoglobin, iron, iron metabolism parameters, copper and zinc concentrations were studied. Haemoglobin concentration resulted higher at the end of the fattening for calves fed the mix diet, as expected. Values remained, however, within ranges that allowed acceptable carcass paleness. Haematic iron, unsaturated iron binding capacity (UIBC and total iron binding capacity (TIBC levels were not significantly different between the two solid feeds. Lower copper and zinc blood concentrations resulted for calves fed the mix diet were likely due to the feed fibre interfering with the bioavailability of the two minerals, according to what happens for iron.

  8. Preconcentration of trace amounts of lead in water samples with cetyltrimethylammonium bromide coated magnetite nanoparticles and its determination by flame atomic absorption spectrometry

    Directory of Open Access Journals (Sweden)

    Mohammad Faraji

    2016-11-01

    Full Text Available A sensitive and simple magnetic solid phase extraction procedure was presented for the preconcentration of lead ions in environmental water samples. In the present study, lead ions form complexes with 1-(2-pyridilazo-2-naphthol reagent (PAN in basic medium, and then are quantitatively extracted to the surface of cetyltrimethylammonium bromide (CTAB-coated magnetite nanoparticles (Fe3O4 NPs. After magnetic separation of adsorbent, the adsorbent was eluted with 0.5% (v/v HCl in methanol prior to its analysis by flame atomic absorption spectrometry (FAAS. The pH of sample, concentrations of PAN, amounts of CTAB and Fe3O4 NPs, sample volume and desorption conditions were optimized. Under optimum conditions, the calibration curve was linear in the range of 0.05–100 ng mL−1 with R2 = 0.9996. Detection and quantification limits of the proposed method were 0.005 and 0.05 ng mL−1, respectively. Enhancement factor of 1050 was achieved using this method to extract 1000 mL of different environmental water samples. Compared with conventional solid phase extraction methods, the advantages of this method still include easy preparation of sorbents, short times of sample pre-treatment, high extraction yield, and high breakthrough volume. It shows great analytical potential in preconcentration of lead from large volume water samples.

  9. Investigation of properties of copper, ferrous complexes with 1-(5-bromo-2-pyridylazo)-2-naphthol-6-sulphonic acid and application of substitution reaction in metallic complex to selective determination of trace amounts of metal.

    Science.gov (United States)

    Gao, H W

    2000-08-16

    The report was the first to establish the new method for the selective determination of trace amounts of metal using the substitution reaction in metallic complex. The reactions between copper(II) and 1-(5-bromo-2-pyridylazo)-2-naphthol-6-sulphonic acid (BPANS) and between ferrous(II) and BPANS at pH 3.5 were studied. In absence of any masking reagent, the recommended method was selective in the determination of trace amounts of copper with Fe-BPANS complex as chromogenic reagent because copper(II) can substitute Fe from Fe-BPANS complex to form Cu-BPANS complex. The ordinary spectrophotometric method was unsuitable to the substitution reaction because the excess of Fe-BPANS complex had the high absorption and affected seriously the absorption of Cu-BPTANS complex. The spectral correction principle may eliminate the above influence to give the simple determination of the composition ratio, stepwise absorptivity (epsilon) and stability constant (K) of metal complex. For analysis of samples, the recovery of copper was between 96.5 and 106% with R.S.D. less than 5%.

  10. Combination of solid phase extraction and dispersive liquid–liquid microextraction for separation/preconcentration of ultra trace amounts of uranium prior to its fiber optic-linear array spectrophotometry determination

    Energy Technology Data Exchange (ETDEWEB)

    Dadfarnia, Shayessteh, E-mail: sdadfarnia@yazd.ac.ir; Shabani, Ali Mohammad Haji; Shakerian, Farid; Shiralian Esfahani, Golnaz

    2013-12-15

    Graphical abstract: Pass the sample through the basic alumina column ⇒ elute retained uranium along with the cations ⇒ convert the uranium to its anionic benzoate complex ⇒ extract its ion pair with malachite green into small volume of chloroform by DLLME ⇒ measure its absorption at 621 nm using fiber optic-linear array detection spectrophotometry. -- Highlights: • By combination of SPE and DDLME a high preconcentration factor of 2500 was obtained. • Development of SPE-DDLME-Spectrophotometric method for det. of trace amounts of uranium. • Ultra trace amount of uranium in water samples was det. by the proposed method. • The detection limit of the proposed method is comparable to the most sensitive method. • The proposed method is a free interference spectrophotometric method for uranium det. -- Abstract: A simple and sensitive method for the separation and preconcentration of the ultra trace amounts of uranium and its determination by spectrophotometry was developed. The method is based on the combination of solid phase extraction and dispersive liquid–liquid microextraction. Thus, by passing the sample through the basic alumina column, the uranyl ion and some cations are separated from the sample matrix. The retained uranyl ion along with the cations are eluted with 5 mL of nitric acid (2 mol L{sup −1}) and after neutralization of the eluent, the extracted uranyl ion is converted to its anionic benzoate complex and is separated from other cations by extraction of its ion pair with malachite green into small volume of chloroform using dispersive liquid–liquid microextraction. The amount of uranium is then determined by the absorption measurement of the extracted ion pair at 621 nm using flow injection spectrophotometry. Under the optimum conditions, with 500 mL of the sample, a preconcentration factor of 1980, a detection limit of 40 ng L{sup −1}, and a relative standard deviation of 4.1% (n = 6) at 400 ng L{sup −1} were obtained. The

  11. Simultaneous spectrophotometric determination of trace amounts of uranium, thorium, and zirconium using the partial least squares method after their preconcentration by alpha-benzoin oxime modified Amberlite XAD-2000 resin.

    Science.gov (United States)

    Ghasemi, Jahan B; Zolfonoun, E

    2010-01-15

    A new solid phase extraction method for separation and preconcentration of trace amounts of uranium, thorium, and zirconium in water samples is proposed. The procedure is based on the adsorption of U(VI), Th(IV) and Zr(IV) ions on a column of Amberlite XAD-2000 resin loaded with alpha-benzoin oxime prior to their simultaneous spectrophotometric determination with Arsenazo III using orthogonal signal correction partial least squares method. The enrichment factor for preconcentration of uranium, thorium, and zirconium was found to be 100. The detection limits for U(VI), Th(IV) and Zr(IV) were 0.50, 0.54, and 0.48microgL(-1), respectively. The precision of the method, evaluated as the relative standard deviation obtained by analyzing a series of 10 replicates, was below 4% for all elements. The practical applicability of the developed sorbent was examined using synthetic seawater, natural waters and ceramic samples.

  12. Solid-phase extraction and determination of trace amount of some metal ions on Duolite XAD 761 modified with a new Schiff base as chelating agent in some food samples.

    Science.gov (United States)

    Marahel, F; Ghaedi, M; Montazerozohori, M; Biyareh, M Nejati; Kokhdan, S Nasiri; Soylak, M

    2011-01-01

    A method for preconcentration of trace heavy metal ions in environmental samples has been reported. The presented method is based on the sorption of Cr(3+), Co(2+), Cu(2+), Fe(3+), Ni(2+), and Zn(2+) ions with 2-(2,4-dichlorobenzylideneamino) benzenethiol as respective chelate on modified Duolite XAD 761. The metals content of the sorbed complexes are eluted using 6 ml of 4M nitric acid. The influences of the analytical parameters including pH, amount of ligand and solid phase and condition of eluting solution, the effects of matrix ions on the retentions of the analytes were examined. The recoveries of analytes are generally higher than 94% and the RSD is between 1.5% and 2.2%. The method has been successfully applied for the evaluation of understudy metals content in some food samples.

  13. A new quaternary photoluminescence enhancement system of Eu-N-(o-vanillin)-1,8-diaminonaphthalene-1,10-phenanthroline-Zn and its application in determining trace amounts of europium and zinc.

    Science.gov (United States)

    Zhou, Yunshan; Ahmad, Waqar; An, Yugang; Zhang, Lijuan; Zheng, Xiaorui

    2014-08-01

    A new sensitive quaternary photoluminescence enhancement system has been successfully developed to determine trace amounts of Eu(3+) and Zn(2+). The photoluminescence intensity of Eu - N-(o-vanilin)-1,8-diaminonaphthalene systems was greatly increased by the addition of specific concentrations of 1, 10-phenanthroline and Zn(2+). The excitation and emission wavelengths were 274 and 617 nm, respectively. Under optimal system conditions, the photoluminescence intensity showed a linear response toward Eu(3+) in the range of 5.0 × 10(-6)  ~ 2.0 × 10(-5)  M with a limit of detection (= 2.2 × 10(-9)  M) and the photoluminescence intensity of the system decreased linearly by increasing the Zn(2+) concentration in the range of 5.0 × 10(-8)  ~ 1.0 × 10(-6)  M with a limit of detection (= 8.8 × 10(-11)  M). This system was successfully applied for the determination of trace amounts of Eu(3+) in a high purity La2O3 matrix and in the synthetic rare earth oxide mixture, and of Zn(2+) in a high purity Mg(NO3)2 · 6H2O matrix and in synthetic coexisting ionic matrixes. The energy transfer mechanism, photoluminescence enhancement of the system and interference of other lanthanide ions and common coexisting ions were also studied in detail. Copyright © 2013 John Wiley & Sons, Ltd.

  14. Determination of trace amount of thallium in water samples by electrothermal atomic absorption spectrometry with cloud point extraction%浊点萃取电热原子吸收光谱法测定水中痕量铊

    Institute of Scientific and Technical Information of China (English)

    陈海婷; 陈建国; 林力; 金献忠; 魏丹毅

    2009-01-01

    Cloud point extraction (CPE) has been used for pre-concentration of trace amount of thallium in water samples after the formation of a complex with ammonium pyrrolidine dithiocarbamate, and then analysed by electrothermal absorption spectrometry (ETAAS) using octylphenoxypolyethoxyethanol (Triton X-114) as a surfactant. The effects of experimental conditions on cloud point extraction and atomization processes were optimized carefully. Under the optimum conditions, the limit of detection was 0.07 μg/L (3a) , the relative standard deviation was found to be 3.6% for a sample containing 4.0 μg/L Tl(Ⅲ) (n=7) . The recoveries was ranged from 93% to 106% , and the preconcentra-tion factor was 31. The method has been successfully applied to the determination of trace amount of thallium in tap and river water samples, and the satisfactory recoveries have been obtained.%采用吡咯烷基二硫代氨基甲酸铵(APDC)为螯合剂, Triton X-114作为表面活性剂, 建立了浊点萃取预富集电热原子吸收光谱法测定水中痕量铊的方法. 在优化的实验条件下, 方法的检出限可达0.07 μg/L, 相对标准偏差为3.6% (4 μg/L, n=7), 加标回收率为93%~106%, 富集倍率为31. 该方法成功应用于自来水和河水中痕量铊的测定.

  15. Combination of solid phase extraction and dispersive liquid-liquid microextraction for separation/preconcentration of ultra trace amounts of uranium prior to its fiber optic-linear array spectrophotometry determination.

    Science.gov (United States)

    Dadfarnia, Shayessteh; Shabani, Ali Mohammad Haji; Shakerian, Farid; Shiralian Esfahani, Golnaz

    2013-12-15

    A simple and sensitive method for the separation and preconcentration of the ultra trace amounts of uranium and its determination by spectrophotometry was developed. The method is based on the combination of solid phase extraction and dispersive liquid-liquid microextraction. Thus, by passing the sample through the basic alumina column, the uranyl ion and some cations are separated from the sample matrix. The retained uranyl ion along with the cations are eluted with 5 mL of nitric acid (2 mol L(-1)) and after neutralization of the eluent, the extracted uranyl ion is converted to its anionic benzoate complex and is separated from other cations by extraction of its ion pair with malachite green into small volume of chloroform using dispersive liquid-liquid microextraction. The amount of uranium is then determined by the absorption measurement of the extracted ion pair at 621 nm using flow injection spectrophotometry. Under the optimum conditions, with 500 mL of the sample, a preconcentration factor of 1980, a detection limit of 40 ng L(-1), and a relative standard deviation of 4.1% (n=6) at 400 ng L(-1) were obtained. The method was successfully applied to the determination of uranium in mineral water, river water, well water, spring water and sea water samples.

  16. Fate of biosolids trace metals in a dryland wheat agroecosystem

    Science.gov (United States)

    Biosolids land application for beneficial reuse applies varying amounts of trace metals to soils. Measuring plant-available or total soil metals is typically performed to ensure environmental protection, yet these techniques do not quantify which soil phases play important roles in terms of metal r...

  17. Application of In-Syringe Dispersive Liquid-Liquid Microextraction and Narrow-Bore Tube Dispersive Liquid-Liquid Microextraction for the Determination of Trace Amounts of BTEX in Water Samples.

    Science.gov (United States)

    Rahmani, Mashaallah; Kaykhaii, Massoud; Ghasemi, Elham; Tahernejad, Mohadeseh

    2015-08-01

    Two new simple and effective methods based on dispersive liquid-liquid microextraction (DLLME) procedure, termed "in-syringe DLLME (IS-DLLME)" and "narrow-bore tube DLLME (NB-DLLME)", were developed and applied for rapid and simultaneous separation and preconcentration of trace amounts of benzene, toluene, ethylbenzene and xylene isomers in water samples followed by gas chromatographic analysis. Different parameters influencing the extraction efficiency of both methods such as type and volume of the extraction solvent and the disperser solvent; pH, temperature and volume of sample solution and ionic strength of samples were investigated and optimized. Under optimal condition, the limits of detection ranged from 1.7 to 2.4 µg L(-1) for IS-DLLME and 1.5 to 2.2 µg L(-1) for NB-DLLME. Precision (as relative standard deviation) of the two techniques was between 2.1 and 4.6% for IS-DLLME and between 1.5 and 4.5% for NB-DLLME. The enrichment factors found to be between 20-29 and 31-73 for IS- and NB-DLLME, respectively. The applicability of the proposed methods was investigated by analyzing real water samples.

  18. Application of Deep Eutectic Solvent Modified Cotton as a Sorbent for Online Solid-Phase Extraction and Determination of Trace Amounts of Copper and Nickel in Water and Biological Samples.

    Science.gov (United States)

    Karimi, Mehdi; Dadfarnia, Shayessteh; Shabani, Ali Mohammad Haji

    2017-03-01

    Deep eutectic solvent (DES) was used as the extractant to improve the extraction properties of cotton. DES of choline chloride-urea (ChCl-urea) was prepared and immobilized on the surface of cotton fibers. The resulting sorbent was packed on a microcolumn, and a flow injection flame atomic absorption spectrometry was designed for the online separation and determination of trace amounts of copper and nickel. Various parameters affecting the extraction recovery of analytes such as pH, sample volume, sample loading rate, nature, volume, concentration, and flow rate of eluent were investigated and optimized. Under the optimum conditions, the method showed good linearity in the concentration range of 0.25-50.0 and 4.0-125.0 μg L(-1) with the coefficient of determination (r (2)) of 0.9991 and 0.9990 for copper and nickel, respectively. The method was very sensitive with the detection limits (defined as 3Sb/m) of 0.05 and 0.60 μg L(-1) for Cu and Ni, respectively. It was successfully applied for the determination of Cu and Ni in water and biological samples. The accuracy of the method was evaluated through the recovery experiments and independent analysis by electrothermal atomic absorption spectrometry.

  19. Determination of ultra-trace amount methyl-, phenyl- and inorganic mercury in environmental and biological samples by liquid chromatography with inductively coupled plasma mass spectrometry after cloud point extraction preconcentration.

    Science.gov (United States)

    Chen, Jianguo; Chen, Hengwu; Jin, Xianzhong; Chen, Haiting

    2009-02-15

    The cloud point extraction (CPE) preconcentration of ultra-trace amount of mercury species prior to reverse-phase high performance liquid chromatography (HPLC) with inductively coupled plasma mass spectrometry (ICP-MS) detection was studied. Mercury species including methyl-, ethyl-, phenyl- and inorganic mercury were transformed into hydrophobic chelates by reaction with sodium diethyldithiocarbamate, and the hydrophobic chelates were extracted into a surfactant-rich phase of Triton X-114 upon heating in a water bath at 40 degrees C. Ethylmercury was found partially decomposed during the CPE process, and was not included in the developed method. Various experimental conditions affecting the CPE preconcentration, HPLC separation, and ICP-MS determination were optimized. Under the optimized conditions, detection limits of 13, 8 and 6 ng l(-1) (as Hg) were achieved for MeHg(+), PhHg(+) and Hg(2+), respectively. Seven determinations of a standard solution containing the three mercury species each at 0.5 ng ml(-1) level produced relative standard deviations of 5.3, 2.3 and 4.4% for MeHg(+), PhHg(+) and Hg(2+), respectively. The developed method was successfully applied for the determination of the three mercury species in environmental water samples and biological samples of human hair and ocean fish.

  20. A simple and sensitive spectrophotometric method for the determination of trace amounts of nitrite in environmental and biological samples using 4-amino-5-hydroxynaphthalene-2,7-disulphonic acid monosodium salt

    Science.gov (United States)

    Nagaraja, Padmarajaiah; Al-Tayar, Naef Ghllab S.; Shivakumar, Anantharaman; Shrestha, Ashwine K.; Gowda, Avinash K.

    2010-05-01

    A very simple, sensitive, fairly selective and rapid spectrophotometric method for the determination of trace amounts of nitrite has been described. This method is based on the diazotized intramolecular coupling of electrophilic diazonium cation with the phenolic group of 4-amino-5-hydroxynaphthalene-2,7-disulphonic acid monosodium salt (AHNDMS) in a phosphate buffer solution of pH 7.5. The cyclic product has a purple color with maximum absorbance at 560 nm and is stable for 6 h. Optimum reaction conditions and other important analytical parameters for the maximum color development were established. Beer's law was found to obey for nitrite in the concentration range of 0.1-1.6 μg ml -1 with molar absorptivity of 2.6 × 10 4 l mol -1 cm -1 and Sandell's sensitivity of 0.0075 μg ml -1. The effect of interfering ions on the determination is described. The recommended method was applied for the determination of nitrite in different water, soil and human saliva samples. The performance of the recommended method was evaluated in terms of Student's t-test and variance ratio F-test, which indicated the significance of proposed method over the reference method.

  1. A rapid method for the detection of foodborne pathogens by extraction of a trace amount of DNA from raw milk based on amino-modified silica-coated magnetic nanoparticles and polymerase chain reaction.

    Science.gov (United States)

    Bai, Yalong; Song, Minghui; Cui, Yan; Shi, Chunlei; Wang, Dapeng; Paoli, George C; Shi, Xianming

    2013-07-17

    A method based on amino-modified silica-coated magnetic nanoparticles (ASMNPs) and polymerase chain reaction (PCR) was developed to rapidly and sensitively detect foodborne pathogens in raw milk. After optimizing parameters such as pH, temperature, and time, a trace amount of genomic DNA of pathogens could be extracted directly from complex matrices such as raw milk using ASMNPs. The magnetically separated complexes of genomic DNA and ASMNPs were directly subjected to single PCR (S-PCR) or multiplex PCR (M-PCR) to detect single or multiple pathogens from raw milk samples. Salmonella Enteritidis (Gram-negative) and Listeria monocytogenes (Gram-positive) were used as model organisms to artificially contaminate raw milk samples. After magnetic separation and S-PCR, the detection sensitivities were 8 CFU mL(-1) and 13 CFU mL(-1) respectively for these two types of pathogens. Furthermore, this method was successfully used to detect multiple pathogens (S. Enteritidis and L. monocytogenes) from artificially contaminated raw milk using M-PCR at sensitivities of 15 CFU mL(-1) and 25 CFU mL(-1), respectively. This method has great potential to rapidly and sensitively detect pathogens in raw milk or other complex food matrices.

  2. 表面活性剂增敏催化分光光度法测定痕量锰%Surfactant-Sensitized Catalytic Spectrophotometric Determination of Trace Amount of Manganese

    Institute of Scientific and Technical Information of China (English)

    耿卫东; 张丹扬; 杨亚玲

    2011-01-01

    In the presence of surfactant polyethylene glycol-400(PEG-400),the color-fading of the dyestuff "sunset yellow" by oxidation with sodium persulfate was catalyzed by manganese(Ⅱ),and the stability and speed of the color-fading reaction were obviously enhanced.Based on these facts,a surfactant-sensitized catalytic spectrophotometric method for determination of trace amount of manganese(Ⅱ) was proposed.Linear relationship between the magnitude of decrease in absorbance ΔA and mass concentration of manganese(Ⅱ) was obtained in the range of 0.05-4.0 mg·L-1.Detection limit(3S/N) found was 20 μg·L-1.In the determination of trace of manganese(Ⅱ) in water samples by the proposed method,values of recovery found by standard addition method were in the range from 98.6% to 101.8%,with values of RSD′s(n=5) less than 1.5%.%在表面活性剂聚乙二醇-400(PEG-400)存在下,锰(Ⅱ)对过硫酸钠氧化日落黄(一种染料)的褪色反应具有催化作用,且对此反应的速度及稳定性有明显提高。在此基础上提出了测定锰的催化分光光度法。锰(Ⅱ)的质量浓度在0.05~4.0mg.L-1范围内与ΔA呈线性关系。方法的检出限(3S/N)为20μg.L-1。方法用于水样中痕量锰的测定,并做回收试验,测得回收率在98.6%~101.8%之间,测定值的相对标准偏差(n=5)小于1.5%。

  3. Selective and sensitive spectrophotometric method for the determination of trace amounts of zirconium in environmental and biological samples using 4-chloro-N-(2,6-dimethylphenyl)-2-hydroxy-5-sulfamoylbenzamide

    Science.gov (United States)

    Al-Kady, Ahmed S.

    2012-11-01

    A simple, selective and sensitive spectrophotometric method for the determination of trace amounts of Zr(IV) in aqueous samples was performed, based on complexation reaction between Zr(IV) and 4-chloro-N-(2,6-dimethylphenyl)-2-hydroxy-5-sulfamoylbenzamide (xipamide). The important analytical parameters and their effects on the reported system were investigated. Zr(IV) react with xipamide in the ratio 1:1 in the pH range 8 to form a complex with an absorption maximum 333 nm. The apparent stability constant (log βn) and the free energy change (ΔG∗) of formation of the complex was calculated using the results of mole ratio and continuous variation methods. Beer's law was obeyed in the concentration range 0.2-3.6 μg/mL. For more accurate analysis, Ringbom optimum concentration range was found from 0.3 to 3.5 μg/mL. The molar absorptivity, Sandell sensitivity, detection and quantification limits were also calculated. Taking a constant concentration of Zr(IV) and determining its concentration in the presence of large number of foreign ions tested the effect of foreign ions. The practical applicability of the elaborated method was examined using for determination of mentioned ion in water samples, biological, plant leaves and soil samples where excellent agreements between reported and obtained results were achieved. The relative standard deviation (n = 6) were 0.195%. The precision and accuracy of the results were comparable via F and t test at the 95% confidence level.

  4. FAAS Determination of Trace Amount of Iron in Huaiqing Chinese Medicines with Cloud Point Extraction%浊点萃取-火焰原子吸收光谱法测定怀药中微量铁

    Institute of Scientific and Technical Information of China (English)

    李英杰; 侯广顺

    2012-01-01

    在pH4.0介质中,以二乙基二硫代氨基甲酸钠(DDTC)为螯合剂,铁与DDTC生成疏水性螯合物,加入Triton X-114表面活性剂用浊点萃取分离富集怀药中微量铁。表面活性剂相用0.01mol·L-1盐酸溶液定容至0.6mL后,所得溶液直接用火焰原子吸收光谱法进行测定。对影响浊点萃取的因素和共存离子的干扰进行了试验并予以优化。铁的检出限(3σ)为0.4μg·L-1。应用此法测定了怀药(怀山药、怀地黄、怀牛膝、怀菊花)中铁的含量,用标准加入法进行方法的回收试验,测得回收率在90.7%~111.2%之间,测定值的相对标准偏差(n=6)在2.5%~4.5%之间。%Trace amount of Fe was separated and enriched from the sample solution buffered at pH 4.0 in the form of hydrophobic coordination complex with DDTC by cloud point extraction using Triton X-114 as surfactant. The surfactant phase was diluted and made up to 0. 6 mL with 0. 01 mol·L-1 HCl and the content of Fe was determined by FAAS. Influential factors to cloud point extraction, and interferences of co-existing ions were studied and optimized. Detection limit (3σ) of the method was found to be 0. 4μg·L-1. The proposed method was applied to the determination of Fe in samples of Huaiqing Chinese medicines (Huaiqing Chinese yam, radices rehmanniae, achyranthes and chrysanthemum), and values of recovery obtained by standard addition method were in the range of 90. 7%--111.2% with RSD's (n=6) in the range of 2. 5%--4. 5%.

  5. Determination of trace amounts of silver in oxaliplatin by fluorescence quenching of CdTe quantum dots%CdTe量子点荧光猝灭法测定奥沙利铂中微量银

    Institute of Scientific and Technical Information of China (English)

    董微; 徐淑坤; 王莹

    2012-01-01

    以谷胱甘肽作为稳定剂,100℃恒温回流,直接合成水溶性CdTe量子点.基于Ag+对合成的CdTe量子点的荧光猝灭效应,建立了测定抗癌药物奥沙利铂中微量银的方法.考察了量子点浓度、缓冲液种类、缓冲液浓度、缓冲液pH和反应时间对银离子测定的影响.当量子点浓度为0.004g/L时,在0.10mmol/LpH7.4的磷酸缓冲溶液中,反应时间为5min,体系的相对荧光强度与Ag+的质量浓度呈良好的线性关系,其线性范围为16.42~98.50μg/L,线性相关系数为0.9975,检出限为0.12μg/L.%Water-soluble CdTe quantum dots (QDs) were synthesized by means of L-glutathione (GSH) as a modifying agent in an aqueous solution at 100 ℃. Based on the quenching of the fluorescence intensity of CdTe QDs by Ag(I) , a simple, rapid and sensitive method for the determination of trace amounts of silver in anti-cancer drug oxaliplatin was developed. In the study, the effects of experimental conditions, including concentration of CdTe QDs, the type, concentration and pH of buffer, and reacting time on the determination of Ag (I) were investigated in detail. When the concentration of QDs was 0.004 g/L in the phosphate buffer at pH 7. 4, the fluorescence quenching intensity of the CdTe QDs was linear with Ag (I) mass concentration in the range of 16. 42 ~ 98. 50 μg/L, with a linear correlation coefficient of 0. 9975. The limit of detection (3( ) was 0. 12 μ.g/L.

  6. Selective Flow-Injection Quantification of Ultra-trace Amounts of Cr(VI) via On-line Complexation and Preconcentration with APDC Followed by Determination by Electrothermal Atomic Absorption Spectrometry

    DEFF Research Database (Denmark)

    Nielsen, Steffen; Hansen, Elo Harald

    1998-01-01

    is effected by adsorption on the inner wall of a knotted reactor made from PTFE tubing. The complex is subsequently eluted with a monosegmented discrete zone of ethanol (55 mu l), and the analyte is quantified by electrothermal atomic absorption spectrometry (ETAAS). The operations of the FI...

  7. Zirconia-coated graphite adsorption bar micro-extraction combined with ETV-ICP-MS for the determination of trace amounts of Cd, Hg and Pb in environmental and biological samples.

    Science.gov (United States)

    Pu, Xuli; Jiang, Zucheng; Hu, Bin

    2006-07-01

    In this work, a new and simple micro-extraction method termed graphite adsorption bar micro-extraction was developed, for the first time, for electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) determination of trace Cd, Hg and Pb. In this method, the graphite bar was first coated with zirconia and then inserted into the sample solution for extraction. The graphite bar enriched with the analytes was inserted directly into a graphite tube, and subsequently analyzed by ETV-ICP-MS according to an established temperature program. The experimental parameters, which had influence on the extraction and vaporization, were systematically investigated and the optimal experimental conditions were established. Under the optimized conditions, the detection limits of the method were 0.05, 0.42 and 0.06 pg/ml for Cd, Hg and Pb and the relative standard deviations (RSDs) for 11 replicates at the 0.1 ng/ml level were 7.4, 8.2 and 7.7%, respectively. The proposed method was successfully applied to the determination of trace Cd, Hg and Pb in environmental and biological samples. The results of the experiments indicate that the method has a high enrichment factor and sample utilization efficiency. Furthermore, the method is fast and environment-friendly.

  8. Quantifying the Amount of Ice in Cold Tropical Cirrus Clouds

    Science.gov (United States)

    Avery, Melody A.; Winker, David M.; Garnier, Anne; Lawson, R. Paul; Heymsfield, Andrew J.; Mo, Qixu; Schoeberl, Mark R.; Woods, Sarah; Lance, Sara; Young, Stuart A.; Vaughan, Mark A.; Trepte, Charles R.

    2014-01-01

    How much ice is there in the Tropical Tropopause layer, globally? How does one begin to answer that question? Clouds are currently the largest source of uncertainty in climate models, and the ice water content (IWC) of cold cirrus clouds is needed to understand the total water and radiation budgets of the upper troposphere and lower stratosphere (UT/LS). The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite, originally a "pathfinder" mission only expected to last for three years, has now been operational for more than eight years. Lidar data from CALIPSO can provide information about how IWC is vertically distributed in the UT/LS, and about inter-annual variability and seasonal changes in cloud ice. However, cloud IWC is difficult to measure accurately with either remote or in situ instruments because IWC from cold cirrus clouds is derived from the particle cross-sectional area or visible extinction coefficient. Assumptions must be made about the relationship between the area, volume and density of ice particles with various crystal habits. Recently there have been numerous aircraft field campaigns providing detailed information about cirrus ice water content from cloud probes. This presentation evaluates the assumptions made when creating the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) global IWC data set, using recently reanalyzed aircraft particle probe measurements of very cold, thin TTL cirrus from the 2006 CR-AVE.

  9. 浊点萃取光度法测定水样中亚硝酸根%Determination of trace amount of nitrite in water samples by spectrophotometric with cloud point extraction

    Institute of Scientific and Technical Information of China (English)

    丁宗庆; 张琼瑶

    2009-01-01

    A new method for the determination of trace nitrite by spectrophotometric after cloud point extraction was proposed.The effects of experimental conditions such as acidity,concentration of chromogenic reagent and surfactant,equilibration temperature and time on cloud point extraction were discussed.Under the optimum conditions,a good linear relationship was obtained in the range of 4.0~200 μg/L of the nitrite (r=0.9998),the detection limits of 0.43 μg/L.The recoveries fell in the range from 97.7% to 102.4% and the relative standard deviations were between 1.8% and 3.2%.This method has been applied for the determination of nitrite in real water samples with satisfactory results.

  10. The use of rapidly synergistic cloud point extraction for the separation and preconcentration of trace amounts of Ni (II) ions from food and water samples coupling with flame atomic absorption spectrometry determination.

    Science.gov (United States)

    Rahnama, Reyhaneh; Najafi, Marzieh

    2016-03-01

    A novel improved preconcentration method known as rapidly synergistic cloud point extraction (RS-CPE) was established for nickel preconcentration and determination prior to its determination by flame atomic absorption spectrometry. In this work, the traditional CPE pattern was changed and greatly simplified in order to be applicable in metal extraction and detection. This method was accomplished in room temperature in 1 min. Non-ionic surfactant Triton X-114 was used as extractant. Octanol worked as cloud point revulsant and synergic reagent. The various parameters affecting the extraction and preconcentration of nickel such as sample pH, 2,2'-Furildioxime concentration, amounts of octanol, amounts of Triton X-114, type of diluting solvent, extraction time, and ionic strength were investigated and optimized. Under optimal conditions, the calibration curve showed an excellent linearity in the concentration range of 2-200 μg L(-1), and the limit of detection was 0.6 μg L(-1) for nickel. The developed method was successfully applied for the determination of nickel in food and water samples. The results showed that, the proposed method can be used as a cheap, rapid, and efficient method for the extraction and preconcentration of nickel from real samples.

  11. Quantifying Concordance

    CERN Document Server

    Seehars, Sebastian; Amara, Adam; Refregier, Alexandre

    2015-01-01

    Quantifying the concordance between different cosmological experiments is important for testing the validity of theoretical models and systematics in the observations. In earlier work, we thus proposed the Surprise, a concordance measure derived from the relative entropy between posterior distributions. We revisit the properties of the Surprise and describe how it provides a general, versatile, and robust measure for the agreement between datasets. We also compare it to other measures of concordance that have been proposed for cosmology. As an application, we extend our earlier analysis and use the Surprise to quantify the agreement between WMAP 9, Planck 13 and Planck 15 constraints on the $\\Lambda$CDM model. Using a principle component analysis in parameter space, we find that the large Surprise between WMAP 9 and Planck 13 (S = 17.6 bits, implying a deviation from consistency at 99.8% confidence) is due to a shift along a direction that is dominated by the amplitude of the power spectrum. The Surprise disa...

  12. Solid-Phase Extraction of Trace Amounts of Uranium(VI in Environmental Water Samples Using an Extractant-Impregnated Resin Followed by Detection with UV-Vis Spectrophotometry

    Directory of Open Access Journals (Sweden)

    Ahmad Hosseini-Bandegharaei

    2013-01-01

    Full Text Available A stable extractant-impregnated resin (EIR containing Chrome Azurol B was prepared using Amberlite XAD-2010 as a porous polymeric support. The new EIR was employed for trace separation and preconcentration of U(VI ion followed by spectrophotometric determination with the arsenazo III procedure. CAB/XAD-2010 exhibited excellent selectivity for U(VI ion over coexisting ions. Experimental parameters including pH, contact time, shaking speed, and ionic strength were investigated by batch extraction methods. Maximum sorption of U(VI ions occurred at pH 4.3–6.9. The capacity of EIR was found to be 0.632 mmol·g−1. Equilibrium was reached in 25 min and the loading half-time, t1/2, was less than 6 min. The equilibrium adsorption isotherm of U(VI was fitted with the Langmuir adsorption model. In addition, a column packed with CAB/XAD-2010 was used for column-mode separation and preconcentration of U(VI ion. For the optimization of the dynamic procedure, effects of sample volume, sample and eluent flow rate, eluent concentration, and its volume were investigated. The preconcentration factors for U(VI were found out to be 160. But, for convenience, a preconcentration factor of 150 was utilized for the column-mode preconcentration. The dynamic procedure gave a detection limit of 5.0×10-10 mol·L−1 (0.12 μg·L−1 for U(VI ion. The proposed dynamic method showed good performance in analyzing environmental water samples.

  13. Soil trace metals and analytical chemistry; Metaux traces des sols et chimie analytique

    Energy Technology Data Exchange (ETDEWEB)

    Bermond, A. [Institut National Agronomique, Lab. de Chimie Analytique, 75 - Paris (France)

    2004-09-01

    The hazard due to the presence of large amounts of trace metals in some soils is strongly related to what we call the speciation of these metals. This so-called speciation is usually performed with extracting reagents, that is to say corresponds to the use of chemical reagents in order to extract metallic cations from a soil sample and to quantify the extracted metals in the solution when equilibrium is reached. This paper is more particularly devoted to the use for this purpose of two reagents, hydrogen peroxide and EDTA. (author)

  14. Quantification of ultra-trace amounts of copper by using off-line solid phase extraction-flame atomic absorption spectrometric determination through the octadecyl silica-bonded phase membrane (OSPM) C18 disks impregnated with 2,2'-[ethane-1,2-diylbis(thio)]dianiline.

    Science.gov (United States)

    Mohammadhosseini, Majid; Soliemani, Esmaeil

    2014-07-01

    This study reports a very selective, easy, and precise method for rapid separation of trace amounts of copper in aqueous samples using octadecyl silica-bonded phase membrane disks modified by 2,2'-[ethane-1,2-diylbis(thio)]dianiline (EDTD) combined with flame atomic absorption spectrometric determination. In addition, the synthesis and spectral characterization of EDTD have been described in detail. All the affecting experimental variables such as pH, amount of modifier, eluent type, sample and eluent flow rate, interfering ions, and disk capacity were also investigated. The target analyte (trace copper) was quantitatively retained at pH = 4 and eluted with 6.0 mL of 0.5 M HNO3 at flow rates of 40 and 10 mL min−1 for analyte passage and elution steps, respectively, through the disks modified with 17.0 mg of EDTD. The proposed method also allows an enrichment factor of about 500 and has a detection limit of 0.005 ng mL−1. The method has been successfully applied for isolation and determination of copper in different water samples, peppers, and standard alloys.

  15. Quantifying resilience

    Science.gov (United States)

    Allen, Craig R.; Angeler, David G.

    2016-01-01

    The biosphere is under unprecedented pressure, reflected in rapid changes in our global ecological, social, technological and economic systems. In many cases, ecological and social systems can adapt to these changes over time, but when a critical threshold is surpassed, a system under stress can undergo catastrophic change and reorganize into a different state. The concept of resilience, introduced more than 40 years ago in the ecological sciences, captures the behaviour of systems that can occur in alternative states. The original definition of resilience forwarded by Holling (1973) is still the most useful. It defines resilience as the amount of disturbance that a system can withstand before it shifts into an alternative stable state. The idea of alternative stable states has clear and profound implications for ecological management. Coral reefs, for example, are high-diversity systems that provide key ecosystem services such as fisheries and coastal protection. Human impacts are causing significant, ongoing reef degradation, and many reefs have shifted from coral- to algal-dominated states in response to anthropogenic pressures such as elevated water temperatures and overfishing. Understanding and differentiating between the factors that help maintain reefs in coral-dominated states vs. those that facilitate a shift to an undesired algal-dominated state is a critical step towards sound management and conservation of these, and other, important social–ecological systems.

  16. solid phase extraction of trace amounts of palladium ions using ...

    African Journals Online (AJOL)

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    hydroxybenzylidene)- ... applied to the determination of palladium ion in environmental samples. KEY WORDS: ... preparation tool and provides a method that is simple and safe to use. .... and recovery of ions was investigated under optimum conditions.

  17. SOLID PHASE EXTRACTION OF TRACE AMOUNTS OF ZINC AND ...

    African Journals Online (AJOL)

    ions in the water and food samples and satisfactory results were obtained. ... extraction, cloud point extraction, coprecipitation, membrane filtration .... Approximately 5.0 g of dry rice, spaghetti, bread and black tea samples were taken in four.

  18. Kinetic spectrophotometric determination of trace amounts of selenium and vanadium

    Energy Technology Data Exchange (ETDEWEB)

    Safavi, A.; Sedghy, H.R.; Shams, E. [Dept. of Chemistry, Shiraz Univ. (Iran)

    1999-11-01

    A sensitive kinetic spectrophotometric method has been developed for the determination of Se(IV) over the range of 45 to 4000 ng in 10 mL of solution. The method is based on the catalytic effect of Se(IV) on the reduction reaction of bromate by hydrazinium dichloride, with subsequent reaction of Ponceau S with products of the above reaction (chlorine and bromine), causing color changing of Ponceau S. Method development includes optimization of time interval for measurement of slope, pH, reagents concentration, and temperature. The optimized conditions yielded a theoretical detection limit of 33 ng/10 mL of solution of Se(IV). The interfering effects were studied and removed. The method was applied to the determination of selenium in spiked water, Kjeldahl tablet, selenium tablet, and shampoo. Vanadium(V) has an inhibition effect on the catalyzed reaction of bromate and hydrazine by selenium. Using this effect, V(V) can be determined in the range of 70 to 2500 ng in 10 mL of solution. The optimization procedure includes pH and selenium concentration. An extraction method was used for interference removal. The method was applied to the determination of vanadium in petroleum. (orig.)

  19. Study of trace amounts of U in snuff

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, P.K.; Lal, N.; Nagpaul, K.K.

    1985-06-01

    Snuff is an indigenous preparation of powdered tobacco and wood ash or calcium hydroxide. Although the excess risk of oral cancer among snuff users has been observed in the southern United States, India and Southeast Asia, there is still uncertainty about those constituents responsible for the cancer. The health effects of U have not been considered in regard to tobacco smoking because U is not volatile at temperatures of a burning cigarette and hence is not inhaled. But snuff may be held in the mouth several times a day through the adult life of an individual and may be swallowed. The authors have not found any report of radioactivity measurements in snuff and decided to take up the present work.

  20. Determination of trace amounts of cobalt in blood

    Energy Technology Data Exchange (ETDEWEB)

    Godlewska, B.; Hulanicki, A. [Univ. of Warsaw (Poland); Abou-Shakra, F.R. [Univ. of Surrey, Guildford (United Kingdom)] [and others

    1994-11-01

    The analysis of cobalt in whole blood and blood fractions has been carried out using three different analytical techniques namely, electrothermal atomic absorption spectrometry, inductively coupled plasma mass spectrometry and cathodic stripping voltammetry. This study showed that inductively coupled plasma mass spectrometry was the better equipped technique for conducting such analyses due to its low detection limits and wide linear dynamic range. The results ranged between 0.7 - 2.62 {mu}g/l for plasma, 1.02 - 2.31 {mu}g/l for serum, and 0.66 - 1.28 {mu}g/l for whole blood. The introduction of different forms of cobalt to Wistar rats resulted in a differing distribution of the element between serum and whole blood. This observation suggests that there are at least two modes of Co uptake and transport depending on the administered or taken chemical form.

  1. Catalytic Kinetic Photometric Determination of Trace Amount of Iridium( Ⅲ ) by the Reaction System of Brilliant Green and Hydrogen Peroxide%亮绿-过氧化氢系统催化动力学光度法测定痕量铱(Ⅲ)

    Institute of Scientific and Technical Information of China (English)

    魏成富; 唐杰; 王洪福; 罗娅君; 张琴

    2012-01-01

    在0.01 mol.L-1硫酸介质中,95℃水浴加热10 min时,痕量铱(Ⅲ)对过氧化氢氧化亮绿褪色反应有显著的催化作用。据此提出了催化动力学光度法测定痕量铱(Ⅲ)的方法。该催化反应对铱(Ⅲ)为一级反应,总反应为准一级反应。催化反应的表观速率常数为7.383×10-4s-1,表观活化能为65.27 kJ.mol-1。铱(Ⅲ)的质量浓度在0.06 mg.L-1以内与吸光度的减小(ΔA)呈线性关系,检出限(3s/k)为1.152×10-7g.L-1。方法用于分子筛和活性炭样品中铱(Ⅲ)量的测定,回收率在97%~104%之间。%In 0. 01 mol . L^-1 H2SO4 medium and heated in a water bath at 95 ℃ for 10 min, the oxidative color-fading reaction of brilliant green with H2 O2 was remarkably catalyzed by the presence of trace amount of It( Ⅲ ). Based on these facts, a catalytic kinetic photometric method for determination of trace amount of Ir(Ⅲ ) was proposed. It was proved that the catalytic process was a first order reaction for Ir ( Ⅲ ) and a pseudo first order reaction for total reaction. Values of apparent rate constant and apparent activation energy were found to be 7. 383×10^-4 s^-1 and 65.27 kJ .mol^-1 respectively. Linear relationship between the values of decrease in absorbance (AA) and mass concentration of Ir( Ⅲ ) was obtained in the range within 0. 06 mg . L^-1. Detection limit (3s/k) of the reaction found was 1. 152 × 10-7 g . L^-1. In analyzing samples of molecular sieve and activated carbon by this method for Ir(Ⅲ) contents, giving recovery in the range of 97 %- 104%.

  2. Quantifying human vitamin kinetics using AMS

    Energy Technology Data Exchange (ETDEWEB)

    Hillegonds, D; Dueker, S; Ognibene, T; Buchholz, B; Lin, Y; Vogel, J; Clifford, A

    2004-02-19

    Tracing vitamin kinetics at physiologic concentrations has been hampered by a lack of quantitative sensitivity for chemically equivalent tracers that could be used safely in healthy people. Instead, elderly or ill volunteers were sought for studies involving pharmacologic doses with radioisotopic labels. These studies fail to be relevant in two ways: vitamins are inherently micronutrients, whose biochemical paths are saturated and distorted by pharmacological doses; and while vitamins remain important for health in the elderly or ill, their greatest effects may be in preventing slow and cumulative diseases by proper consumption throughout youth and adulthood. Neither the target dose nor the target population are available for nutrient metabolic studies through decay counting of radioisotopes at high levels. Stable isotopic labels are quantified by isotope ratio mass spectrometry at levels that trace physiologic vitamin doses, but the natural background of stable isotopes severely limits the time span over which the tracer is distinguishable. Indeed, study periods seldom ranged over a single biological mean life of the labeled nutrients, failing to provide data on the important final elimination phase of the compound. Kinetic data for the absorption phase is similarly rare in micronutrient research because the phase is rapid, requiring many consecutive plasma samples for accurate representation. However, repeated blood samples of sufficient volume for precise stable or radio-isotope quantitations consume an indefensible amount of the volunteer's blood over a short period. Thus, vitamin pharmacokinetics in humans has often relied on compartmental modeling based upon assumptions and tested only for the short period of maximal blood circulation, a period that poorly reflects absorption or final elimination kinetics except for the most simple models.

  3. Provenance Traces

    CERN Document Server

    Cheney, James; Ahmed, Amal

    2008-01-01

    Provenance is information about the origin, derivation, ownership, or history of an object. It has recently been studied extensively in scientific databases and other settings due to its importance in helping scientists judge data validity, quality and integrity. However, most models of provenance have been stated as ad hoc definitions motivated by informal concepts such as "comes from", "influences", "produces", or "depends on". These models lack clear formalizations describing in what sense the definitions capture these intuitive concepts. This makes it difficult to compare approaches, evaluate their effectiveness, or argue about their validity. We introduce provenance traces, a general form of provenance for the nested relational calculus (NRC), a core database query language. Provenance traces can be thought of as concrete data structures representing the operational semantics derivation of a computation; they are related to the traces that have been used in self-adjusting computation, but differ in impor...

  4. Forensic trace DNA: a review

    Science.gov (United States)

    2010-01-01

    DNA analysis is frequently used to acquire information from biological material to aid enquiries associated with criminal offences, disaster victim identification and missing persons investigations. As the relevance and value of DNA profiling to forensic investigations has increased, so too has the desire to generate this information from smaller amounts of DNA. Trace DNA samples may be defined as any sample which falls below recommended thresholds at any stage of the analysis, from sample detection through to profile interpretation, and can not be defined by a precise picogram amount. Here we review aspects associated with the collection, DNA extraction, amplification, profiling and interpretation of trace DNA samples. Contamination and transfer issues are also briefly discussed within the context of trace DNA analysis. Whilst several methodological changes have facilitated profiling from trace samples in recent years it is also clear that many opportunities exist for further improvements. PMID:21122102

  5. The Emergence of the Quantified Child

    Science.gov (United States)

    Smith, Rebecca

    2017-01-01

    Using document analysis, this paper examines the historical emergence of the quantified child, revealing how the collection and use of data has become normalized through legitimizing discourses. First, following in the traditions of Foucault's genealogy and studies examining the sociology of numbers, this paper traces the evolution of data…

  6. Determination of trace amount of iron and copper in titanium oxide by graphite furnace atomic absorption spectrophotometer with slurry sampling%悬浮进样石墨炉原子吸收法测定氧化钛中痕量元素铁和铜

    Institute of Scientific and Technical Information of China (English)

    王丽晖; 张虹; 李辉; 董园园; 李爱民

    2012-01-01

    The determination of trace amount of iron and copper was studied by graphite furnace atomic absorption spectrometry (GFAAS). Slurry sampling was adopted, which simplified the operation precesses and samples were not contaminated and lossed. 10 g/L Ni(N0s)2was used as chemical modifiers, which improved ashing temperature of iron and stabilized the signal. The recovery rate of Fe and Cu is 103% and 98% , respectively. The relative standard deviation of Fe and Cu is 4.46% and 3.24%. The calibration graph is in the range of 2 to 80 p-g/L for Fe, and 0.5 to 20 |xg/Lfor Cu. The character mass of Fe is 0.47 μg/L, and Cu is 0.63 μg/L.%采用石墨炉原子吸收光谱法测定氧化钛中痕量元素铁、铜,采用悬浮进样,样品不用消化,简化操作步骤,避免样品的沾污和损失.10 g/LNi(NO3)2作基体改进剂,提高铁的灰化温度,检测信号得到扩大.回收率Fe为103%,Cu为98%,相对标准偏差Fe为4.46%,Cu为3.24%.Fe的线性范围为2~80 μg/L,Cu的线性范围为0.5~20 μg/L.Fe的特征质量浓度为0.47 μg/L,Cu为0.63 μg/L.结果表明,该方法简便、快速、稳定、准确度高.

  7. Quantifying traffic exposure.

    Science.gov (United States)

    Pratt, Gregory C; Parson, Kris; Shinoda, Naomi; Lindgren, Paula; Dunlap, Sara; Yawn, Barbara; Wollan, Peter; Johnson, Jean

    2014-01-01

    Living near traffic adversely affects health outcomes. Traffic exposure metrics include distance to high-traffic roads, traffic volume on nearby roads, traffic within buffer distances, measured pollutant concentrations, land-use regression estimates of pollution concentrations, and others. We used Geographic Information System software to explore a new approach using traffic count data and a kernel density calculation to generate a traffic density surface with a resolution of 50 m. The density value in each cell reflects all the traffic on all the roads within the distance specified in the kernel density algorithm. The effect of a given roadway on the raster cell value depends on the amount of traffic on the road segment, its distance from the raster cell, and the form of the algorithm. We used a Gaussian algorithm in which traffic influence became insignificant beyond 300 m. This metric integrates the deleterious effects of traffic rather than focusing on one pollutant. The density surface can be used to impute exposure at any point, and it can be used to quantify integrated exposure along a global positioning system route. The traffic density calculation compares favorably with other metrics for assessing traffic exposure and can be used in a variety of applications.

  8. Quantifying the Digital Traces of Hurricane Sandy on Flickr

    OpenAIRE

    Preis, Tobias; Moat, Helen Susannah; Bishop, Steven R.; Treleaven, Philip; Stanley, H. Eugene

    2013-01-01

    Society’s increasing interactions with technology are creating extensive “digital traces” of our collective human behavior. These new data sources are fuelling the rapid development of the new field of computational social science. To investigate user attention to the Hurricane Sandy disaster in 2012, we analyze data from Flickr, a popular website for sharing personal photographs. In this case study, we find that the number of photos taken and subsequently uploaded to Flickr with titles, desc...

  9. Devices and methods to detect and quantify trace gases

    Energy Technology Data Exchange (ETDEWEB)

    Allendorf, Mark D.; Robinson, Alex

    2016-05-03

    Sensing devices based on a surface acoustic wave ("SAW") device coated with an absorbent crystalline or amorphous layer for detecting at least one chemical analyte in a gaseous carrier. Methods for detecting the presence of a chemical analyte in a gaseous carrier using such devices are also disclosed. The sensing devices and methods for their use may be configured for sensing chemical analytes selected from the group consisting of water vapor, carbon dioxide, methanol, ethanol, carbon monoxide, nitric oxide, nitrous oxide, organic amines, organic compounds containing NO.sub.2 groups, halogenated hydrocarbons, acetone, hexane, toluene, isopropanol, alcohols, alkanes, alkenes, benzene, functionalized aromatics, ammonia (NH.sub.3), phosgene (COCl.sub.2), sulfur mustard, nerve agents, sulfur dioxide, tetrahydrofuran (THF) and methyltertbutyl ether (MTBE) and combinations thereof.

  10. 分散液液微萃取-石墨炉原子吸收光谱法测定环境水样中的痕量镉%Determination of trace amount of cadmium in environmental water samples using dispersive liquid-liquid microextraction coupled with graphite furnace atomic absorption spectrometry

    Institute of Scientific and Technical Information of China (English)

    马晓国; 罗颂华; 曾倩

    2011-01-01

    建立了分散液液微萃取分离富集-石墨炉原子吸收光谱法测定环境水样中痕量镉的新方法.以二乙基二硫代氨基甲酸钠为螯合剂、四氯化碳为萃取剂、丙酮为分散剂,详细考察了pH值、螯合剂质量分数、萃取剂体积、萃取时间等因素的影响.在优化的实验条件下,方法对水样中镉的检出限为4.2 ng·L-1,线性范围是20~300 ng·L-1,测定结果的相对标准偏差为3.5%,富集倍数达103.将建立的方法应用于三种实际环境水样中镉的检测,加标回收率在92%~ 108%范围内.本方法具有灵敏、准确、快速、环保的特点,是一种分析水样中痕量镉的较好方法.%A novel method for determination of trace amount of cadmium in environmental water samples by graphite furnace atomic absorption spectrometry coupled with dispersive liquid-liquid micro-extraction was developed. Sodium diethyldithiocarbamatre (DDTC), carbon tetrachloride and acetone were used as the chelating agent, extraction solvent and dispersive solvent, respectively. The effects of sample pH, DDTC concentration, extractant volume and extraction time on cadmium extraction were investigated in detail. It was found that under the optimal conditions, the limit of detection for cadmium was 4.2 ng-L"1, the relative standard deviation (RSD) was 3.5%, and the linear range was between 20 and 300 ng-L"1. Three water samples were analyzed by the established method with spiked recoveries of 92-108%. The proposed analytical technique is sensitive, accurate, rapid and environmentally friendly.

  11. 硫酸钠盐析对萃取微量铜的增敏作用及其应用%Sensitizing effect of sodium-sulfate salting-out phase separation in extraction of trace amount of copper ions and its application

    Institute of Scientific and Technical Information of China (English)

    廖晓祥; 李晖; 李延芳; 梁冰

    2011-01-01

    A new Na2SO4sahing-out extraction method has been developed for preconcentration trace amounts of copper as a prior step to its determination by UV-visible spectrophotometry, in which diethyldithiocarbamate(DDTC) was used as complexing agent,with chloroform as extraction solvent.Variables affecting salting-out extraction efficiency were investigated and optimized.Under the optimal conditions, the calibration curve was linear in the range of 0.002 μg/mL ~ 0.08 μg/mLof copper, detection limit was 0.11 ng/mL in original solution (3Sbc/m) and the relative standard deviation for seven replicate determination of 0.002 μg/mL copper was ± 1.9%.The proposed method has been applied for determination of copper in Honeysuckle, Radix Glycyrrhiza,Lycium samples with satisfactory results, the recovery were 103%, 102% ,96%, RSD were 1.5%, 1.9%, 2.0%, respectively.%建立了以二乙基二硫代氨基甲酸钠(DDTC)为络合剂,硫酸钠-氯仿-水盐析萃取,紫外可见分光光度法测定痕量铜(Ⅱ)的新方法.研究了萃取的条件,共存离子的干扰.结果表明本法灵敏度高,选择性好,在最佳实验条件下,铜的线性范围为0.002~0.08μg/mL,0.002μg/mL铜标准液测定的RSD=1.9%(n=7),检出限为0.11ng/mL.应用于金银花、甘草、枸杞中铜的测定,回收率分别为103%、102%、96%,RSD分别为1.5%、1.9%、2.0%.

  12. Quantifiers, Anaphora and Intensionality

    CERN Document Server

    Dalrymple, M; Pereira, F C N; Saraswat, V; Dalrymple, Mary; Lamping, John; Pereira, Fernando; Saraswat, Vijay

    1995-01-01

    The relationship between Lexical-Functional Grammar (LFG) {\\em functional structures} (f-structures) for sentences and their semantic interpretations can be expressed directly in a fragment of linear logic in a way that correctly explains the constrained interactions between quantifier scope ambiguity, bound anaphora and intensionality. This deductive approach to semantic interpretaion obviates the need for additional mechanisms, such as Cooper storage, to represent the possible scopes of a quantified NP, and explains the interactions between quantified NPs, anaphora and intensional verbs such as `seek'. A single specification in linear logic of the argument requirements of intensional verbs is sufficient to derive the correct reading predictions for intensional-verb clauses both with nonquantified and with quantified direct objects. In particular, both de dicto and de re readings are derived for quantified objects. The effects of type-raising or quantifying-in rules in other frameworks here just follow as li...

  13. Decomposing generalized quantifiers

    NARCIS (Netherlands)

    Westerståhl, D.

    2008-01-01

    This note explains the circumstances under which a type <1> quantifier can be decomposed into a type <1, 1> quantifier and a set, by fixing the first argument of the former to the latter. The motivation comes from the semantics of Noun Phrases (also called Determiner Phrases) in natural languages, b

  14. Decomposing generalized quantifiers

    NARCIS (Netherlands)

    Westerståhl, D.

    2008-01-01

    This note explains the circumstances under which a type <1> quantifier can be decomposed into a type <1, 1> quantifier and a set, by fixing the first argument of the former to the latter. The motivation comes from the semantics of Noun Phrases (also called Determiner Phrases) in natural languages,

  15. Understanding quantifiers in language

    NARCIS (Netherlands)

    Szymanik, J.; Zajenkowski, M.; Taatgen, N.; van Rijn, H.

    2009-01-01

    We compare time needed for understanding different types of quantifiers. We show that the computational distinction between quantifiers recognized by finite-automata and push-down automata is psychologically relevant. Our research improves upon hypothesis and explanatory power of recent neuroimaging

  16. Connected Car: Quantified Self becomes Quantified Car

    Directory of Open Access Journals (Sweden)

    Melanie Swan

    2015-02-01

    Full Text Available The automotive industry could be facing a situation of profound change and opportunity in the coming decades. There are a number of influencing factors such as increasing urban and aging populations, self-driving cars, 3D parts printing, energy innovation, and new models of transportation service delivery (Zipcar, Uber. The connected car means that vehicles are now part of the connected world, continuously Internet-connected, generating and transmitting data, which on the one hand can be helpfully integrated into applications, like real-time traffic alerts broadcast to smartwatches, but also raises security and privacy concerns. This paper explores the automotive connected world, and describes five killer QS (Quantified Self-auto sensor applications that link quantified-self sensors (sensors that measure the personal biometrics of individuals like heart rate and automotive sensors (sensors that measure driver and passenger biometrics or quantitative automotive performance metrics like speed and braking activity. The applications are fatigue detection, real-time assistance for parking and accidents, anger management and stress reduction, keyless authentication and digital identity verification, and DIY diagnostics. These kinds of applications help to demonstrate the benefit of connected world data streams in the automotive industry and beyond where, more fundamentally for human progress, the automation of both physical and now cognitive tasks is underway.

  17. Epidemic contact tracing via communication traces.

    Directory of Open Access Journals (Sweden)

    Katayoun Farrahi

    Full Text Available Traditional contact tracing relies on knowledge of the interpersonal network of physical interactions, where contagious outbreaks propagate. However, due to privacy constraints and noisy data assimilation, this network is generally difficult to reconstruct accurately. Communication traces obtained by mobile phones are known to be good proxies for the physical interaction network, and they may provide a valuable tool for contact tracing. Motivated by this assumption, we propose a model for contact tracing, where an infection is spreading in the physical interpersonal network, which can never be fully recovered; and contact tracing is occurring in a communication network which acts as a proxy for the first. We apply this dual model to a dataset covering 72 students over a 9 month period, for which both the physical interactions as well as the mobile communication traces are known. Our results suggest that a wide range of contact tracing strategies may significantly reduce the final size of the epidemic, by mainly affecting its peak of incidence. However, we find that for low overlap between the face-to-face and communication interaction network, contact tracing is only efficient at the beginning of the outbreak, due to rapidly increasing costs as the epidemic evolves. Overall, contact tracing via mobile phone communication traces may be a viable option to arrest contagious outbreaks.

  18. Periodontal inflamed surface area : quantifying inflammatory burden

    NARCIS (Netherlands)

    Nesse, Willem; Abbas, Frank; van der Ploeg, Ids; Spijkervet, Frederik Karst Lucien; Dijkstra, Pieter Ubele; Vissink, Arjan

    2008-01-01

    Background: Currently, a large variety of classifications is used for periodontitis as a risk factor for other diseases. None of these classifications quantifies the amount of inflamed periodontal tissue, while this information is needed to assess the inflammatory burden posed by periodontitis. Aim:

  19. Periodontal inflamed surface area : quantifying inflammatory burden

    NARCIS (Netherlands)

    Nesse, Willem; Abbas, Frank; van der Ploeg, Ids; Spijkervet, Frederik Karst Lucien; Dijkstra, Pieter Ubele; Vissink, Arjan

    2008-01-01

    Background: Currently, a large variety of classifications is used for periodontitis as a risk factor for other diseases. None of these classifications quantifies the amount of inflamed periodontal tissue, while this information is needed to assess the inflammatory burden posed by periodontitis. Aim:

  20. Quantifying drug-protein binding in vivo.

    Energy Technology Data Exchange (ETDEWEB)

    Buchholz, B; Bench, G; Keating III, G; Palmblad, M; Vogel, J; Grant, P G; Hillegonds, D

    2004-02-17

    Accelerator mass spectrometry (AMS) provides precise quantitation of isotope labeled compounds that are bound to biological macromolecules such as DNA or proteins. The sensitivity is high enough to allow for sub-pharmacological (''micro-'') dosing to determine macromolecular targets without inducing toxicities or altering the system under study, whether it is healthy or diseased. We demonstrated an application of AMS in quantifying the physiologic effects of one dosed chemical compound upon the binding level of another compound in vivo at sub-toxic doses [4].We are using tissues left from this study to develop protocols for quantifying specific binding to isolated and identified proteins. We also developed a new technique to quantify nanogram to milligram amounts of isolated protein at precisions that are comparable to those for quantifying the bound compound by AMS.

  1. Quantifying linguistic coordination

    DEFF Research Database (Denmark)

    Fusaroli, Riccardo; Tylén, Kristian

    ). We employ nominal recurrence analysis (Orsucci et al 2005, Dale et al 2011) on the decision-making conversations between the participants. We report strong correlations between various indexes of recurrence and collective performance. We argue this method allows us to quantify the qualities......Language has been defined as a social coordination device (Clark 1996) enabling innovative modalities of joint action. However, the exact coordinative dynamics over time and their effects are still insufficiently investigated and quantified. Relying on the data produced in a collective decision...

  2. Quantifying synergistic mutual information

    CERN Document Server

    Griffith, Virgil

    2012-01-01

    Quantifying cooperation among random variables in predicting a single target random variable is an important problem in many biological systems with 10s to 1000s of co-dependent variables. We review the prior literature of information theoretical measures of synergy and introduce a novel synergy measure, entitled *synergistic mutual information* and compare it against the three existing measures of cooperation. We apply all four measures against a suite of binary circuits to demonstrate our measure alone quantifies the intuitive concept of synergy across all examples.

  3. Is Time Predictability Quantifiable?

    DEFF Research Database (Denmark)

    Schoeberl, Martin

    2012-01-01

    -case execution time. To compare different approaches we would like to quantify time predictability. That means we need to measure time predictability. In this paper we discuss the different approaches for these measurements and conclude that time predictability is practically not quantifiable. We can only......Computer architects and researchers in the realtime domain start to investigate processors and architectures optimized for real-time systems. Optimized for real-time systems means time predictable, i.e., architectures where it is possible to statically derive a tight bound of the worst...... compare the worst-case execution time bounds of different architectures....

  4. Data Mining of NS-2 Trace File

    Directory of Open Access Journals (Sweden)

    Ahmed Jawad Kadhim

    2014-11-01

    Full Text Available Data mining is important process to extract the use ful information and pattern from huge amount of dat a. NS-2 is an efficient tool to build the environment of network. The results from simulate these environ ment in NS-2 is trace file that contains several columns and lines represent the network events. This trace file can be used to analyse the network according to per formance metrics but it has redundant columns and rows. So, this paper is to perform the data mining in order to find only the necessary information in analysis operation to reduce the execution time and the storage size of the trace file.

  5. Remediation using trace element humate surfactant

    Energy Technology Data Exchange (ETDEWEB)

    Riddle, Catherine Lynn; Taylor, Steven Cheney; Bruhn, Debra Fox

    2016-08-30

    A method of remediation at a remediation site having one or more undesirable conditions in which one or more soil characteristics, preferably soil pH and/or elemental concentrations, are measured at a remediation site. A trace element humate surfactant composition is prepared comprising a humate solution, element solution and at least one surfactant. The prepared trace element humate surfactant composition is then dispensed onto the remediation site whereby the trace element humate surfactant composition will reduce the amount of undesirable compounds by promoting growth of native species activity. By promoting native species activity, remediation occurs quickly and environmental impact is minimal.

  6. Workshop report on quantifying environmental damage from energy activities

    Energy Technology Data Exchange (ETDEWEB)

    Moskowitz, P D; Rowe, M D; Morris, S C; Hamilton, L D

    1977-09-11

    Data and methods for quantifying environmental damage from energy activities were evaluated. Specifically, discussions were designed to identify the types and amounts of pollutants emitted by energy technologies that may affect the environment adversely, methods of estimating spatial and temporal changes in air and water quality resulting from these emissions, spatial and temporal distributions of ecosystems at risk, dose-response functions for pollutants and ecosystems at risk, and environmental and economic variables to be used to measure damage. Emphasis was on available data and on several methods for quantitative estimation of effects of energy on the environment. Damage functions that could be used to quantitate effects of ozone and sulfur oxide on agricultural crops and trees, effects of altered stream depth and velocity patterns on river fish species, and sensitivities of lake chemistry and biology to acid rainfall are listed. Also described are methods for estimating effects of carbon dioxide, sulfur dioxide, ozone, and several other atmospheric pollutants on selected terrestrial communities by using computer modeling techniques. With these techniques, quantitative estimates of the effects of energy on the environment could be developed within one to two years. Brief discussions about effects of nutrient and trace metal discharges on terrestrial ecosystems and about impacts of petroleum hydrocarbon, heat, biocides, and entrainment on aquatic ecosystems are also included.

  7. A dynamic gravimetric standard for trace water.

    Science.gov (United States)

    Brewer, P J; Goody, B A; Woods, P T; Milton, M J T

    2011-10-01

    A system for generating traceable reference standards of water vapor at trace levels between 5 and 2000 nmol/mol has been developed. It can provide different amount fractions of trace water vapor by using continuous accurate measurements of mass loss from a permeation device coupled with a dilution system based on an array of critical flow orifices. An estimated relative expanded uncertainty of ±2% has been achieved for most amount fractions generated. The system has been used in an international comparison and demonstrates excellent comparability with National Metrology Institutes maintaining standards of water vapor in this range using other methods.

  8. Identification of organically associated trace elements in wood and coal by inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Richaud, R.; Lazaro, M.J.; Lachas, H.; Miller, B.B.; Herod, A.A.; Dugwell, D.R.; Kandiyoti, R. [Imperial College of Science, Technology and Medicine, London (United Kingdom). Dept. of Chemical Engineering and Chemical Technology

    2000-07-01

    1-Methyl-2-pyrrolidinone (NMP) was used to extract samples of wood (forest residue) and coal; the extracts were analysed by inductively coupled plasma mass spectrometry (ICP-MS) using two different sample preparation methods, in order to identify trace elements associated with the organic part of the samples. A sample of fly ash was similarly extracted and analysed. Size exclusion chromatograms of the extracts indicated the presence of significant amounts of large molecular mass materials ({gt} 1000 {mu}) in the biomass and coal extracts but not in the ash extract. Trace element analyses were carried out using ICP-MS on the acid digests prepared by 'wet ashing' and microwave extraction. Sixteen elements (As, Ba, Be, Cd, Co, Cr, Cu, Ga, Mn, Mo, Ni, pH, Sb, Se, V and Zn) were quantified, in the samples before extraction, in the extracts and in the residues. Concentrations of trace elements in the original biomass samples were lower than in the coal sample while the concentrations in the ash sample were the highest. The major trace elements in the NMP extracts were Ba, Cu, Mn and Zn from the forest residue; Ba, Cu, Mn, Pb and Zn from the coal; Cu and Zn from the ash. These elements are believed to be associated with the organic extracts from the forest residue and coal, and also from the ash.

  9. Trace analysis in complex mixtures using a high-component filtering strategy with liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Zhang, Hui; Wang, Shao-Qing; Liu, Ying; Luo, Li-Ping; Liu, Peng; Qi, Lian-Wen; Li, Ping

    2012-11-01

    Trace constituents are widely present in complex mixtures, and trace analysis is challenging because of the unpredictable matrix. In this work, a high-component filtering strategy was developed for improved analysis of trace constituents in complex sample by liquid chromatography-mass spectrometry (LC-MS). Using a specifically designed chromatographic apparatus, the high-abundant fractions were filtered prior to LC-MS analysis. The samples complexity was reduced and the sample-loading amount for the rest low-level fractions can be considerably increased. The application of this approach was illustrated with an analytically challenging sample, a traditional Chinese herbal medicine named Compound Danshen Sample. We observed that the loss rate for 12 analytes during the filtering procedure ranged from 6.54 to 26.11%, but showed a stable repeatability with RSDanalysis, allowing six low compounds that cannot be quantified by the traditional methods to be tested by the filtering method. It can be predicted that the qualitative and quantitative trace analysis will be greatly improved when the loading samples is increased resulting from the filtration of high-level targets. The proposed strategy is promising to monitor trace constituents in diverse complex mixtures in the analytical field of pharmaceutics, metabonomics and environments.

  10. Quantifying energy condition violations in traversable wormholes

    Indian Academy of Sciences (India)

    Sayan Kar; Naresh Dadhich; Matt Visser

    2004-10-01

    The `theoretical' existence of traversable Lorentzian wormholes in the classical, macroscopic world is plagued by the violation of the well-known energy conditions of general relativity. In this brief article we show: (i) how the extent of violation can be quantified using certain volume integrals and (ii) whether this `amount of violation' can be minimised for some specific cut-and-paste geometric constructions. Examples and possibilities are also outlined.

  11. On Quantifying Semantic Information

    Directory of Open Access Journals (Sweden)

    Simon D’Alfonso

    2011-01-01

    Full Text Available The purpose of this paper is to look at some existing methods of semantic information quantification and suggest some alternatives. It begins with an outline of Bar-Hillel and Carnap’s theory of semantic information before going on to look at Floridi’s theory of strongly semantic information. The latter then serves to initiate an in-depth investigation into the idea of utilising the notion of truthlikeness to quantify semantic information. Firstly, a couple of approaches to measure truthlikeness are drawn from the literature and explored, with a focus on their applicability to semantic information quantification. Secondly, a similar but new approach to measure truthlikeness/information is presented and some supplementary points are made.

  12. Quantifying renewable groundwater stress with GRACE

    Science.gov (United States)

    Richey, Alexandra S.; Thomas, Brian F.; Lo, Min‐Hui; Reager, John T.; Voss, Katalyn; Swenson, Sean; Rodell, Matthew

    2015-01-01

    Abstract Groundwater is an increasingly important water supply source globally. Understanding the amount of groundwater used versus the volume available is crucial to evaluate future water availability. We present a groundwater stress assessment to quantify the relationship between groundwater use and availability in the world's 37 largest aquifer systems. We quantify stress according to a ratio of groundwater use to availability, which we call the Renewable Groundwater Stress ratio. The impact of quantifying groundwater use based on nationally reported groundwater withdrawal statistics is compared to a novel approach to quantify use based on remote sensing observations from the Gravity Recovery and Climate Experiment (GRACE) satellite mission. Four characteristic stress regimes are defined: Overstressed, Variable Stress, Human‐dominated Stress, and Unstressed. The regimes are a function of the sign of use (positive or negative) and the sign of groundwater availability, defined as mean annual recharge. The ability to mitigate and adapt to stressed conditions, where use exceeds sustainable water availability, is a function of economic capacity and land use patterns. Therefore, we qualitatively explore the relationship between stress and anthropogenic biomes. We find that estimates of groundwater stress based on withdrawal statistics are unable to capture the range of characteristic stress regimes, especially in regions dominated by sparsely populated biome types with limited cropland. GRACE‐based estimates of use and stress can holistically quantify the impact of groundwater use on stress, resulting in both greater magnitudes of stress and more variability of stress between regions. PMID:26900185

  13. The Trace of Superusers

    DEFF Research Database (Denmark)

    Samson, Kristine; Abasolo, José

    2013-01-01

    of people’s everyday life.However, traces of culture, the routines and every day habits of immigrant culture can both emerge through informal colonization in the every day and be intentionally designed. By juxtaposing immigrant spatial traces in Santiago Centro with the intentionally designed traces......The city and its public spaces can be seen as a fragmented whole carrying meanings and traces of culture, use and politics with it. Whereas architects impose new stories and meanings on the urban fabric, the city itself is layered and assembled, a collective of social flows and routines a result...... of immigrant culture at Superkilen, Nørrebro in Copenhagen, this article seeks to discuss how traces influence public space, and how various ideologies and even politics are interwoven into the urban fabric by means of urban traces....

  14. Simultaneous Determination of Trace Amount of Chlorite,Chlorate and Common Inorganic Anions in Running Water with kOH Isocratic Elution by Ion Chromatographic Method%KOH等度淋洗IC法同时测定自来水中微量ClO2-、ClO3-及常规阴离子

    Institute of Scientific and Technical Information of China (English)

    陈东; 罗倚坪

    2014-01-01

    The method to determine a trace of chlorite, chlorate and common inorganic anions in running water with KOH isocratic elution by ion chromatography was investigated. The conditions of method was that the concentration of KOH is 20. 5 mmol/L, the flow rate is 1. 0 mL/min, and the injection volume is 50 μL. The results showed that the concentration of F-,Cl-,NO3 -, SO4 2-,ClO2 -,ClO3 - in water was determined completely only in 12 minutes. The correlation coefficients of calibration curve was 0. 997 0-0. 999 9,while the detection limits was between 0. 05-7. 00 μg/L. The relative standard deviation( RSD) and the recoveries were between 0. 61%-3. 82%and 97. 6%-101. 7%, respectively. The method was sensitive, accurate and rapid, which was favorable to simultaneous quantification of chlorite, chlorate and common inorganic anions in drinking water.%建立了KOH等度淋洗离子色谱法同时测定自来水中微量亚氯酸盐、氯酸盐及氟化物、氯化物、硝酸盐、硫酸盐的分析方法。该方法以20.5 mmol/L KOH为淋洗液,流速1.0 mL/min,进样量50μL。结果表明,6种阴离子可在12分钟内检测完毕,各离子的线性相关系数为0.9970~0.9999;检出限为0.05~7.00μg/L;精密度为0.61%~3.82%;回收率为97.6%~101.7%,能够满足饮用水中这些指标的定量需要,是一种灵敏、准确、快速的理想方法。

  15. Quantum heat traces

    CERN Document Server

    Avramidi, Ivan G

    2016-01-01

    We study new invariants of elliptic partial differential operators acting on sections of a vector bundle over a closed Riemannian manifold that we call the relativistic heat trace and the quantum heat traces. We obtain some reduction formulas expressing these new invariants in terms of some integral transforms of the usual classical heat trace and compute the asymptotics of these invariants. The coefficients of these asymptotic expansion are determined by the usual heat trace coefficients (which are locally computable) as well as by some new global invariants.

  16. Quantum heat traces

    Science.gov (United States)

    Avramidi, Ivan G.

    2017-02-01

    We study new invariants of elliptic partial differential operators acting on sections of a vector bundle over a closed Riemannian manifold that we call the relativistic heat trace and the quantum heat traces. We obtain some reduction formulas expressing these new invariants in terms of some integral transforms of the usual classical heat trace and compute the asymptotics of these invariants. The coefficients of these asymptotic expansion are determined by the usual heat trace coefficients (which are locally computable) as well as by some new global invariants.

  17. Quantifying economic fluctuations

    Science.gov (United States)

    Stanley, H. Eugene; Nunes Amaral, Luis A.; Gabaix, Xavier; Gopikrishnan, Parameswaran; Plerou, Vasiliki

    2001-12-01

    This manuscript is a brief summary of a talk designed to address the question of whether two of the pillars of the field of phase transitions and critical phenomena-scale invariance and universality-can be useful in guiding research on interpreting empirical data on economic fluctuations. Using this conceptual framework as a guide, we empirically quantify the relation between trading activity-measured by the number of transactions N-and the price change G( t) for a given stock, over a time interval [ t, t+Δ t]. We relate the time-dependent standard deviation of price changes-volatility-to two microscopic quantities: the number of transactions N( t) in Δ t and the variance W2( t) of the price changes for all transactions in Δ t. We find that the long-ranged volatility correlations are largely due to those of N. We then argue that the tail-exponent of the distribution of N is insufficient to account for the tail-exponent of P{ G> x}. Since N and W display only weak inter-dependency, our results show that the fat tails of the distribution P{ G> x} arises from W. Finally, we review recent work on quantifying collective behavior among stocks by applying the conceptual framework of random matrix theory (RMT). RMT makes predictions for “universal” properties that do not depend on the interactions between the elements comprising the system, and deviations from RMT provide clues regarding system-specific properties. We compare the statistics of the cross-correlation matrix C-whose elements Cij are the correlation coefficients of price fluctuations of stock i and j-against a random matrix having the same symmetry properties. It is found that RMT methods can distinguish random and non-random parts of C. The non-random part of C which deviates from RMT results, provides information regarding genuine collective behavior among stocks. We also discuss results that are reminiscent of phase transitions in spin systems, where the divergent behavior of the response function at

  18. What is Process Tracing actually tracing?

    DEFF Research Database (Denmark)

    Beach, Derek; Pedersen, Rasmus Brun

    We argue that a lot of the murkiness about what Process Tracing (PT) actually is and how it should be used in practice can be cleared up by identifying three variants of PT within political science: theory-testing PT, theory-building PT, and explaining outcomes PT. The three can be differentiated...... and when we use PT case studies. First, there are differences in what we are actually tracing in the three variants, resulting in different methodological prescriptions for each variant. Second, the types of inferences being made are also different; the variants therefore have different analytical uses...

  19. 电感耦合等离子体质谱法测定铀铌混合氧化物中的钐、铕、钆、镝%Determination of Trace Amounts of Sm,Eu,Gd and Dy in U-Nb Mixed Oxide by Inductively Coupled Plasma Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    龙绍军; 廖志海; 安身平; 王鹏; 乔洪波; 郭蓉; 费浩

    2014-01-01

    建立了应用电感耦合等离子体质谱(ICP-MS)测定铀铌混合氧化物中痕量的稀土元素(Sm、Eu、Gd、Dy)的方法。这四种稀土元素在核燃料中的含量在10-7 g/g以下,但热中子截面很大,准确测定其在核燃料中的含量对于核燃料的研究至关重要。样品经 HNO3-HF 快速溶解后,应用 CL-TBP 萃淋树脂分离 U 基体,以115 In作为测定内标校正基体干扰和仪器漂移,标准模式下应用 ICP-MS定量测定淋洗液中 Sm、Eu、Gd和 Dy,半定量分析基体 U。四种稀土元素的质量浓度为0.01~1.00μg/L,线性关系良好,线性相关系数(r)均大于0.999,检出限为0.001~0.002μg/L。对于添加0.2μg/L的稀土元素,稀土元素的回收率为84.3%~97.3%,相对标准偏差(s r )为5.3%~8.7%(n=6),能够满足实际样品测定需要。%A method was developed for determination of trace rare earth elements (Sm,Eu, Gd and Dy )in U-Nb mixed oxide using inductively coupled plasma mass spectrometry (ICP-MS).Though the contents of these four rare earth elements in nuclear fuel are below 10-7 g/g, the accurate determination of their contents in nuclear fuel is crucially important to the research of nuclear fuel for their thermal neutron-absorption cross-sections are large.After the sample was dissolved fast by HNO3-HF acids,U matrix was separated using CL-TBP extraction resin.115 In was used as internal standard to correct matrix interference and instru-ment drift for quantitative determination of Sm,Eu,Gd and Dy in eluate,semi-quantitative determination of U in eluate by ICP-MS.The method has a good linear correlation (r>0.999)in the range of 0.01-1.00μg/L and the detection limit is between 0.001-0.002μg/L. For the add concentrations of rare earth elements is 0.2 μg/L,the recovery is between 84.3%-97.3% and the relative standard deviation (sr)is between 5.3%-8.7% (n=6).The method can be available in practical application.

  20. Quantifying the adaptive cycle

    Science.gov (United States)

    Angeler, David G.; Allen, Craig R.; Garmestani, Ahjond S.; Gunderson, Lance H.; Hjerne, Olle; Winder, Monika

    2015-01-01

    The adaptive cycle was proposed as a conceptual model to portray patterns of change in complex systems. Despite the model having potential for elucidating change across systems, it has been used mainly as a metaphor, describing system dynamics qualitatively. We use a quantitative approach for testing premises (reorganisation, conservatism, adaptation) in the adaptive cycle, using Baltic Sea phytoplankton communities as an example of such complex system dynamics. Phytoplankton organizes in recurring spring and summer blooms, a well-established paradigm in planktology and succession theory, with characteristic temporal trajectories during blooms that may be consistent with adaptive cycle phases. We used long-term (1994–2011) data and multivariate analysis of community structure to assess key components of the adaptive cycle. Specifically, we tested predictions about: reorganisation: spring and summer blooms comprise distinct community states; conservatism: community trajectories during individual adaptive cycles are conservative; and adaptation: phytoplankton species during blooms change in the long term. All predictions were supported by our analyses. Results suggest that traditional ecological paradigms such as phytoplankton successional models have potential for moving the adaptive cycle from a metaphor to a framework that can improve our understanding how complex systems organize and reorganize following collapse. Quantifying reorganization, conservatism and adaptation provides opportunities to cope with the intricacies and uncertainties associated with fast ecological change, driven by shifting system controls. Ultimately, combining traditional ecological paradigms with heuristics of complex system dynamics using quantitative approaches may help refine ecological theory and improve our understanding of the resilience of ecosystems.

  1. Quantifying loopy network architectures.

    Directory of Open Access Journals (Sweden)

    Eleni Katifori

    Full Text Available Biology presents many examples of planar distribution and structural networks having dense sets of closed loops. An archetype of this form of network organization is the vasculature of dicotyledonous leaves, which showcases a hierarchically-nested architecture containing closed loops at many different levels. Although a number of approaches have been proposed to measure aspects of the structure of such networks, a robust metric to quantify their hierarchical organization is still lacking. We present an algorithmic framework, the hierarchical loop decomposition, that allows mapping loopy networks to binary trees, preserving in the connectivity of the trees the architecture of the original graph. We apply this framework to investigate computer generated graphs, such as artificial models and optimal distribution networks, as well as natural graphs extracted from digitized images of dicotyledonous leaves and vasculature of rat cerebral neocortex. We calculate various metrics based on the asymmetry, the cumulative size distribution and the Strahler bifurcation ratios of the corresponding trees and discuss the relationship of these quantities to the architectural organization of the original graphs. This algorithmic framework decouples the geometric information (exact location of edges and nodes from the metric topology (connectivity and edge weight and it ultimately allows us to perform a quantitative statistical comparison between predictions of theoretical models and naturally occurring loopy graphs.

  2. Uncertainty quantified trait predictions

    Science.gov (United States)

    Fazayeli, Farideh; Kattge, Jens; Banerjee, Arindam; Schrodt, Franziska; Reich, Peter

    2015-04-01

    Functional traits of organisms are key to understanding and predicting biodiversity and ecological change, which motivates continuous collection of traits and their integration into global databases. Such composite trait matrices are inherently sparse, severely limiting their usefulness for further analyses. On the other hand, traits are characterized by the phylogenetic trait signal, trait-trait correlations and environmental constraints, all of which provide information that could be used to statistically fill gaps. We propose the application of probabilistic models which, for the first time, utilize all three characteristics to fill gaps in trait databases and predict trait values at larger spatial scales. For this purpose we introduce BHPMF, a hierarchical Bayesian extension of Probabilistic Matrix Factorization (PMF). PMF is a machine learning technique which exploits the correlation structure of sparse matrices to impute missing entries. BHPMF additionally utilizes the taxonomic hierarchy for trait prediction. Implemented in the context of a Gibbs Sampler MCMC approach BHPMF provides uncertainty estimates for each trait prediction. We present comprehensive experimental results on the problem of plant trait prediction using the largest database of plant traits, where BHPMF shows strong empirical performance in uncertainty quantified trait prediction, outperforming the state-of-the-art based on point estimates. Further, we show that BHPMF is more accurate when it is confident, whereas the error is high when the uncertainty is high.

  3. Quantifying innovation in surgery.

    Science.gov (United States)

    Hughes-Hallett, Archie; Mayer, Erik K; Marcus, Hani J; Cundy, Thomas P; Pratt, Philip J; Parston, Greg; Vale, Justin A; Darzi, Ara W

    2014-08-01

    The objectives of this study were to assess the applicability of patents and publications as metrics of surgical technology and innovation; evaluate the historical relationship between patents and publications; develop a methodology that can be used to determine the rate of innovation growth in any given health care technology. The study of health care innovation represents an emerging academic field, yet it is limited by a lack of valid scientific methods for quantitative analysis. This article explores and cross-validates 2 innovation metrics using surgical technology as an exemplar. Electronic patenting databases and the MEDLINE database were searched between 1980 and 2010 for "surgeon" OR "surgical" OR "surgery." Resulting patent codes were grouped into technology clusters. Growth curves were plotted for these technology clusters to establish the rate and characteristics of growth. The initial search retrieved 52,046 patents and 1,801,075 publications. The top performing technology cluster of the last 30 years was minimally invasive surgery. Robotic surgery, surgical staplers, and image guidance were the most emergent technology clusters. When examining the growth curves for these clusters they were found to follow an S-shaped pattern of growth, with the emergent technologies lying on the exponential phases of their respective growth curves. In addition, publication and patent counts were closely correlated in areas of technology expansion. This article demonstrates the utility of publically available patent and publication data to quantify innovations within surgical technology and proposes a novel methodology for assessing and forecasting areas of technological innovation.

  4. Thin Lens Ray Tracing.

    Science.gov (United States)

    Gatland, Ian R.

    2002-01-01

    Proposes a ray tracing approach to thin lens analysis based on a vector form of Snell's law for paraxial rays as an alternative to the usual approach in introductory physics courses. The ray tracing approach accommodates skew rays and thus provides a complete analysis. (Author/KHR)

  5. Evaluation of metal trace detachment from dosing pumps using PIXE

    Science.gov (United States)

    Lozano, Omar; Mejia, Jorge; Laloy, Julie; Alpan, Lütfiye; Toussaint, Olivier; Dogné, Jean-Michel; Lucas, Stéphane

    2014-07-01

    Metal trace detachment evaluation is essential for instruments destined for pharmaceutical applications, such as pumps. Particle-Induced X-ray Emission (PIXE) was used to determine and quantify metal traces originated from stainless steel and ceramic dosing pumps. Metal traces were quantified from either distilled water samples or cellulose filters in two tests: a short-term test of 16 h mimicking a daily cycle of a dosing pump for industrial applications, and a long-term test of 9 days evaluating the pump wearing. The main result is that ceramic dosing pumps present lower metal detachment than stainless steel counterparts. Traces of Si and Al were found originating from pieces around the pumps (pipes and joints).

  6. Evaluation of metal trace detachment from dosing pumps using PIXE

    Energy Technology Data Exchange (ETDEWEB)

    Lozano, Omar, E-mail: omar.lozanogarcia@unamur.be [Research Centre for the Physics of Matter and Radiation (PMR), Namur Nanosafety Centre (NNC), Namur Research Institute for Life Sciences - NARILIS, University of Namur - UNamur, Rue de Bruxelles 61, B-5000 Namur (Belgium); Mejia, Jorge [Research Centre for the Physics of Matter and Radiation (PMR), Namur Nanosafety Centre (NNC), Namur Research Institute for Life Sciences - NARILIS, University of Namur - UNamur, Rue de Bruxelles 61, B-5000 Namur (Belgium); Laloy, Julie; Alpan, Lütfiye [Namur Thrombosis and Hemostasis Centre (NTHC), Namur Nanosafety Centre (NNC), Namur Research Institute for Life Sciences - NARILIS, University of Namur - UNamur, Rue de Bruxelles 61, B-5000 Namur (Belgium); Toussaint, Olivier [Laboratory of Biochemistry and Cellular Biology (URBC), Namur Nanosafety Centre (NNC), Namur Research Institute for Life Sciences - NARILIS, University of Namur - UNamur, Rue de Bruxelles 61, B-5000 Namur (Belgium); Dogné, Jean-Michel [Namur Thrombosis and Hemostasis Centre (NTHC), Namur Nanosafety Centre (NNC), Namur Research Institute for Life Sciences - NARILIS, University of Namur - UNamur, Rue de Bruxelles 61, B-5000 Namur (Belgium); Lucas, Stéphane [Research Centre for the Physics of Matter and Radiation (PMR), Namur Nanosafety Centre (NNC), Namur Research Institute for Life Sciences - NARILIS, University of Namur - UNamur, Rue de Bruxelles 61, B-5000 Namur (Belgium)

    2014-07-15

    Metal trace detachment evaluation is essential for instruments destined for pharmaceutical applications, such as pumps. Particle-Induced X-ray Emission (PIXE) was used to determine and quantify metal traces originated from stainless steel and ceramic dosing pumps. Metal traces were quantified from either distilled water samples or cellulose filters in two tests: a short-term test of 16 h mimicking a daily cycle of a dosing pump for industrial applications, and a long-term test of 9 days evaluating the pump wearing. The main result is that ceramic dosing pumps present lower metal detachment than stainless steel counterparts. Traces of Si and Al were found originating from pieces around the pumps (pipes and joints)

  7. Identification of organically associated trace elements in wood and coal by inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Richaud, R; Lazaro, M J; Lachas, H; Miller, B B; Herod, A A; Dugwell, D R; Kandiyoti, R

    2000-01-01

    1-Methyl-2-pyrrolidinone (NMP) was used to extract samples of wood (forest residue) and coal; the extracts were analysed by inductively coupled plasma mass spectrometry (ICP-MS) using two different sample preparation methods, in order to identify trace elements associated with the organic part of the samples. A sample of fly ash was similarly extracted and analysed in order to assess the behaviour of the mineral matter contained within the wood and coal samples. 32% of the biomass was extracted at the higher temperature and 12% at room temperature while only 12% of the coal was extracted at the higher temperature and 3% at room temperature. Less than 2% of the ash dissolved at the higher temperature. Size exclusion chromatograms of the extracts indicated the presence of significant amounts of large molecular mass materials (>1000 mu) in the biomass and coal extracts but not in the ash extract. Trace element analyses were carried out using ICP-MS on the acid digests prepared by 'wet ashing' and microwave extraction. Sixteen elements (As, Ba, Be, Cd, Co, Cr, Cu, Ga, Mn, Mo, Ni, Pb, Sb, Se, V and Zn) were quantified, in the samples before extraction, in the extracts and in the residues. Concentrations of trace elements in the original biomass sample were lower than in the coal sample while the concentrations in the ash sample were the highest. The major trace elements in the NMP extracts were Ba, Cu, Mn and Zn from the forest residue; Ba, Cu, Mn, Pb and Zn from the coal; Cu and Zn from the ash. These elements are believed to be associated with the organic extracts from the forest residue and coal, and also from the ash. Be and Sb were not quantified in the extracts because they were present at too low concentrations; up to 40% of Mn was extracted from the biomass sample at 202 degrees C, while Se was totally extracted from the ash sample. For the forest residue, approximately 7% (at room temperature) and 45% (at 202 degrees C) of the total trace elements studied were

  8. Gold Nanoparticles-Based Localized Surface Plasmon Resonance Scattering Analysis Method for the Determination of Trace Amounts of Hg(Ⅱ)%利用纳米金局域表面等离子体共振散射方法检测痕量汞(Ⅱ)

    Institute of Scientific and Technical Information of China (English)

    郑莉; 朱进; 吴飞; 丛妍斌; 谭克俊

    2014-01-01

    caused widespread interest for ap-plications in biological and chemical analysis and detection. In the present work,the authors took advantage of the aggregation-induced localized surface plasmon resonance (LSPR)light scattering signal change of sodium thioglycolate functionalized AuNPs in aqueous solutions to develop a highly efficient optical sensor for Hg(Ⅱ). The as-modified AuNPs demonstrate that high nega-tive charge densities exist on their surfaces at pH 9. 0 Britton-Robinson (BR)buffer solution.The AuNPs occur aggregate in so-lution through chelation in the presence of Hg(Ⅱ). The scanning electron microscope (SEM)images for the AuNPs display typ-ical shapes of these AuNPs as regular and almost individual spherical particles. The color change of the AuNPs solution was in-duced by the addition of Hg(Ⅱ)and it immediately changed from red to purple due to the aggregation. Under optimum condi-tions,a good linear relationship was obtained from 0. 08 to 0. 8μmol·L-1 with a correlation coefficient of 0. 997 6,and the limit of detection (LOD)was 8. 0 nmol·L-1. PEG20000 was employed as a system stabilizer. The proposed method has an excellent selectivity for Hg(Ⅱ)in aqueous medium over other metal ions. The optimum test of reaction conditions,including the amount of AuNPs,pH value,reaction stability and ionic strength,were also investigated. This method has been used for determination of Hg(Ⅱ)successfully in environmental water sample. This approach manifested several advantages including short analysis time,high sensitivity,low cost,excellent selectivity and ease of operation.

  9. Sources and Contents of Heavy Metals and Other Trace Elements in Animal Manure

    Science.gov (United States)

    Trace elements are natural and added components of livestock and poultry feeds. Appropriate amounts of these trace elements in the diet of livestock and poultry ensures both health and reproduction. Unfortunately, many times trace metals that are added to livestock diets by producers or feed compani...

  10. Trace Software Pipelining

    Institute of Scientific and Technical Information of China (English)

    王剑; AndreasKrall; 等

    1995-01-01

    Global software pipelining is a complex but efficient compilation technique to exploit instruction-level parallelism for loops with branches.This paper presents a novel global software pipelining technique,called Trace Software Pipelining,targeted to the instruction-level parallel processors such as Very Long Instruction Word (VLIW) and superscalar machines.Trace software pipelining applies a global code scheduling technique to compact the original loop body.The resulting loop is called a trace software pipelined (TSP) code.The trace softwrae pipelined code can be directly executed with special architectural support or can be transformed into a globally software pipelined loop for the current VLIW and superscalar processors.Thus,exploiting parallelism across all iterations of a loop can be completed through compacting the original loop body with any global code scheduling technique.This makes our new technique very promising in practical compilers.Finally,we also present the preliminary experimental results to support our new approach.

  11. Geometrization of Trace Formulas

    CERN Document Server

    Frenkel, Edward

    2010-01-01

    Following our joint work arXiv:1003.4578 with Robert Langlands, we make the first steps toward developing geometric methods for analyzing trace formulas in the case of the function field of a curve defined over a finite field. We also suggest a conjectural framework of geometric trace formulas for curves defined over the complex field, which exploits the categorical version of the geometric Langlands correspondence.

  12. Trace elements in dialysis.

    Science.gov (United States)

    Filler, Guido; Felder, Sarah

    2014-08-01

    In end-stage chronic kidney disease (CKD), pediatric nephrologists must consider the homeostasis of the multiple water-soluble ions that are influenced by renal replacement therapy (RRT). While certain ions such as potassium and calcium are closely monitored, little is known about the handling of trace elements in pediatric dialysis. RRT may lead to accumulation of toxic trace elements, either due to insufficient elimination or due to contamination, or to excessive removal of essential trace elements. However, trace elements are not routinely monitored in dialysis patients and no mechanism for these deficits or toxicities has been established. This review summarizes the handling of trace elements, with particular attention to pediatric data. The best data describe lead and indicate that there is a higher prevalence of elevated lead (Pb, atomic number 82) levels in children on RRT when compared to adults. Lead is particularly toxic in neurodevelopment and lead levels should therefore be monitored. Monitoring of zinc (Zn, atomic number 30) and selenium (Se, atomic number 34) may be indicated in the monitoring of all pediatric dialysis patients to reduce morbidity from deficiency. Prospective studies evaluating the impact of abnormal trace elements and the possible therapeutic value of intervention are required.

  13. Determination of trace amounts of zearalenone in beverage samples with an electrochemical sensor.

    Science.gov (United States)

    Afzali, D; Padash, M; Mostafavi, A

    2015-11-01

    A simple and sensitive electrochemical sensor is purposed for the preconcentration and determination of zearalenone using a carbon paste electrode modified with multi-walled carbon nanotubes. A differential pulse voltammetric method is employed to study the behavior of zearalenone on this modified electrode. The analytical procedure consists of a closed-circuit accumulation step onto the modified electrode. An anodic peak, related to the oxidation of accumulated and reduced zearalenone on the electrode surface, was observed at 0.40 V. The calibration curve was linear in the range of 2.0-50.0 ng mL(-1). The limit of detection was found to be 0.58 ng mL(-1), and the relative standard deviations for five replicated determinations at 5.0 and 30.0 ng mL(-1) of zearalenone were 2.71 and 1.44%, respectively. The modified electrode was applied successfully for the analysis of zearalenone in different malt beverage samples.

  14. Double preconcentration of trace amounts of cadmium in nail samples and measurement by differential pulse voltammetry.

    Science.gov (United States)

    Shahi, Somayeh; Nateghi, Mohammad Reza

    2015-04-01

    Cadion was coated on carbon powder and used as a solid phase for selective extraction and preconcentration of cadmium ions. Complexed cadmium ions were eluted from solid phase by 5 mL, nitric acid (2.0 M) with the flow rate of 2 mL min(-1).The resulted solution was used for accumulation of the cadmium metal at the surface of the carbon paste electrode at -1.3 V reduction potential. Finally, cadmium was reoxidized and the differential pulse voltammogram recorded at the potential range of -0.55 to -0.2 V. Calibration graph was plotted in the concentration range of 0.5-50 μg L(-1) of cadmium. Detection limit 0.06 μg L(-1) was calculated based on the 3 Sb/m. The RSD was 9.13 % (n = 4) for cadmium concentration of 10 μg L(-1) with preconcentration factor of 100. Method was successfully used for the determination of cadmium in finger nail samples and after spiking the samples, the recoveries were evaluated >96 %.

  15. Elemental speciation of neptunium in ultra trace amount ranges; Elementspeziation von Neptunium im Ultraspurenbereich

    Energy Technology Data Exchange (ETDEWEB)

    Stoebener, Nils

    2013-06-25

    In the presented work, the detection of the isotope Np-237 with resonance ionization mass spectrometry (RIMS) was developed and optimized. In RIMS, sample atoms are excited and ionized with laser radiation in several, resonant steps and are subsequently detected by a mass spectrometer. Energy levels suitable for the excitation and ionization of Np-237 were identified using resonance ionization spectroscopy (RIS). With RIS, more than 300 previously unknown electronic states and autoionizing resonances of Np-237 were identified. Using in-source-RIMS, a limit of detection of 9E+5 atoms was demonstrated for the isotope. The mobility of Np in the environment strongly depends on its elemental speciation. Therefore, safety assessments of proposed nuclear waste repositories require analytical methods for the detection of Np species. CE (capillary electrophoresis) was hyphenated to ICP-MS (inductively coupled plasma mass spectrometry) to examine the distribution of the Np redox species Np(IV) and Np(V), which was possible at Np concentrations as low as 1E-9 mol/L. The method was used to study the interaction of the element with Opalinus Clay at varying conditions. CE-ICP-MS revealed, that under the presence of Fe(II), Np(V) is reduced to Np(IV), which is sorbed onto the clay. This leads to a higher overall Np sorption.

  16. Trace amounts of copper induce neurotoxicity in the cholesterol-fed mice through apoptosis

    National Research Council Canada - National Science Library

    Lu, Jun; Zheng, Yuan-lin; Wu, Dong-mei; Sun, Dong-xu; Shan, Qun; Fan, Shao-hua

    2006-01-01

    ... of its ability to chelate copper ions [7–9] . Cholesterol plays a central role in the development and maintenance of the brain and nervous system [10,11] . Human brain makes up only 2% of the body’s weight, yet contains nearly 25% of its cholesterol. But more evidences have implicated a role of cholesterol in AD [11] . According to the cholesterol-Alzheimer’...

  17. A new system for the spectrophotometric determination of trace amounts of nitrite in environmental samples

    Directory of Open Access Journals (Sweden)

    Cherian Tom

    2006-01-01

    Full Text Available A selective and rapid spectrophotometric method for the determination of nitrite is presented. It is based on the reaction of nitrite with p-nitroaniline in acid medium to form diazonium ion, which is coupled with ethoxyethylenemaleic ester or ethylcyanoacetate in basic medium to form azo dyes, showing absorption maxima at 439 and 465 nm respectively. The method obeys Beer's law in the concentration range of 0.5-16 µg mL-1 of nitrite with ethoxyethylenemaleic ester and 0.2-18 µg mL-1 of nitrite with ethylcyanoacetate. The molar absorptivity and Sandell's sensitivity of p-nitroaniline-ethoxyethylenemaleic ester and p-nitroaniline-ethylcyanoacetate azo dyes are 5.04 X 10(4 L mol-1cm-1, 0.98 X 10-2 µg cm-2 and 1.21 X 10(4 L mol-1 cm-1, 0.98 X 10-2 µg cm-2 respectively. The optimum reaction conditions and other analytical parameters were evaluated. The method was successfully applied to the determination of nitrite in various water samples and soil samples.

  18. PCR method for detecting trace amounts of buckwheat (Fagopyrum spp.) in food.

    Science.gov (United States)

    Hirao, Takashi; Imai, Shinsuke; Sawada, Hiroshi; Shiomi, Nobuo; Hachimura, Satoshi; Kato, Hisanori

    2005-04-01

    Buckwheat often causes severe allergic reactions, even when its ingestion level is extremely low. Therefore, buckwheat is listed in several countries as a common food allergen. In addition to common buckwheat and Tartarian buckwheat that are cultivated and consumed widely, wild buckwheat may be potentially allergenic. Food containing undeclared buckwheat poses a risk to patients with the buckwheat allergy. We describe in this report a PCR method to detect buckwheat DNA by using primers corresponding to the internal transcribed spacer region and the 5.8S rRNA gene. The method is buckwheat-specific and compatible with both cultivated and wild buckwheat of the Fagopyrum spp. Its sensitivity was sufficient to detect 1 ppm (w/w) of buckwheat DNA spiked in wheat DNA. This method should benefit food manufacturers, clinical doctors, and allergic patients by providing information on the presence of buckwheat contamination in food.

  19. Distribution of some trace metals in Syrian phosphogypsum

    Energy Technology Data Exchange (ETDEWEB)

    Al-Masri, M.S.; Amin, Y.; Ibrahim, S.; Al-Bich, F

    2004-05-01

    Distribution of Cu, Cd, Zn and U in a Syrian phosphoric acid plant byproduct, phosphogypsum, has been determined. Uranium, Cd, Zn and Cu were found to be more enhanced in small phosphogypsum particles (45-75 {mu}m) where the highest concentration was found for Cu (51.7 ppm). In addition, the element transfer factors (((Trace element concentration in phosphogypsum (mg/kg))/(Trace element concentration in phosphate rock (mg/kg)))x100) from Syrian phosphate rock to phosphogypsum were calculated and found to be 30, 8 and 17% for Zn, Cd and U, respectively. Moreover, laboratory leaching experiments of phosphogypsum by distilled water, dilute H{sub 2}SO{sub 4} solutions and selective extractants have been performed. Leaching results have shown that around 20% of the U and 100% of the Zn are transferred to the aqueous phase. Batch-wise leaching with dilute H{sub 2}SO{sub 4} solutions shows increased solubility of U, Zn, Cu and Cd from phosphogypsum, while leaching with selective extractants has been performed to determine the amount of exchangeable trace metals which are adsorbed, on gypsum particle surfaces, the amount of trace metals present inside the gypsum lattice, the amount of trace metals associated with organic materials and the amount of trace metals soluble in acids. The results obtained in this study can be utilized to verify the environmentally safe use of phosphogypsum as an amendment to agricultural soils.

  20. Lattice Trace Operators

    Directory of Open Access Journals (Sweden)

    Brian Jefferies

    2014-01-01

    Full Text Available A bounded linear operator T on a Hilbert space ℋ is trace class if its singular values are summable. The trace class operators on ℋ form an operator ideal and in the case that ℋ is finite-dimensional, the trace tr(T of T is given by ∑jajj for any matrix representation {aij} of T. In applications of trace class operators to scattering theory and representation theory, the subject is complicated by the fact that if k is an integral kernel of the operator T on the Hilbert space L2(μ with μ a σ-finite measure, then k(x,x may not be defined, because the diagonal {(x,x} may be a set of (μ⊗μ-measure zero. The present note describes a class of linear operators acting on a Banach function space X which forms a lattice ideal of operators on X, rather than an operator ideal, but coincides with the collection of hermitian positive trace class operators in the case of X=L2(μ.

  1. Quantifying sediment connectivity in Wadi Al-Arab (NW Jordan) using a sediment budget approach

    Science.gov (United States)

    Kraushaar, Sabine; Pöppl, Ronald

    2015-04-01

    Due to data scarcity, sediment connectivity most often only qualitatively describes the potential transfer of sediments through a landscape. However, quantitative information on sediment delivery is of special relevance for modelling approaches as well as for sustainable land and water management, especially in water scarce regions such as Jordan, where valuable water reservoirs suffer from sediment pollution. Measurements are needed to quantify sediment outputs of the different land units and to trace their pathways though the catchments. This study uses the outcomes of a multiple response sediment budget approach conducted in the Wadi al-Arab catchment in northwest Jordan (263.5 km²) to quantify sediment connectivity. The catchment shows a Mediterranean to semi arid climate and consists of carbonatic and marly geology of the Upper Cretaceous. The topography ranges from rolling hills in the East to steeper mountainous areas in the North and West were olive orchards are the main agricultural use. Soil erosion measurements in the main land use units and relevant sediment sources, such as olive orchards, agricultural fields, and natural vegetated slopes uncovered the potential ranges of soil erosion rates in these units. Furthermore, the annual sediment yield in the Wadi Al Arab water reservoir was calculated. With the extrapolation of the erosion rates of the main contributing land use units and the annual sediment amount that reaches the sink, a maximum value of lateral sediment connectivity could be quantified, reaching up to 18%. A multiple sediment fingerprint method was used to delineate the relative contribution of each measured source to the sink based on the lake sediment samples. Supported by additional 137Cs analysis of terrace samples and a survey of the Wadi bed a high longitudinal connectivity could be derived. The applied method mix allowed the quantification of lateral sediment connectivity on catchment scale and gave a comprehensive understanding of

  2. Intraoral gothic arch tracing.

    Science.gov (United States)

    Rubel, Barry; Hill, Edward E

    2011-01-01

    In order to create optimum esthetics, function and phonetics in complete denture fabrication, it is necessary to record accurate maxillo-mandibular determinants of occlusion. This requires clinical skill to establish an accurate, verifiable and reproducible vertical dimension of occlusion (VDO) and centric relation (CR). Correct vertical relation depends upon a consideration of several factors, including muscle tone, inter-dental arch space and parallelism of the ridges. Any errors made while taking maxillo-mandibular jaw relation records will result in dentures that are uncomfortable and, possibly, unwearable. The application of a tracing mechanism such as the Gothic arch tracer (a central bearing device) is a demonstrable method of determining centric relation. Intraoral Gothic arch tracers provide the advantage of capturing VDO and CR in an easy-to-use technique for practitioners. Intraoral tracing (Gothic arch tracing) is a preferred method of obtaining consistent positions of the mandible in motion (retrusive, protrusive and lateral) at a comfortable VDO.

  3. Global amount of dust in the universe

    CERN Document Server

    Fukugita, Masataka

    2011-01-01

    It is pointed out that the total amount of dust in the Universe that is produced in stellar evolution in the entire cosmic time is consistent with the observed amount, if we add to the dust amount inferred for galactic discs the amount recently uncovered in galactic haloes and the surrounding of galaxies in reddening of the quasar light passing through the vicinity of galaxies. The inventory concerning the dust closes. This implies that dust produced from stars should survive effectively for the cosmic time, and that a substantial amount of dust is produced in the burning phase of evolved stars of intermedaite mass.

  4. Atom trap trace analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Z.-T.; Bailey, K.; Chen, C.-Y.; Du, X.; Li, Y.-M.; O' Connor, T. P.; Young, L.

    2000-05-25

    A new method of ultrasensitive trace-isotope analysis has been developed based upon the technique of laser manipulation of neutral atoms. It has been used to count individual {sup 85}Kr and {sup 81}Kr atoms present in a natural krypton sample with isotopic abundances in the range of 10{sup {minus}11} and 10{sup {minus}13}, respectively. The atom counts are free of contamination from other isotopes, elements,or molecules. The method is applicable to other trace-isotopes that can be efficiently captured with a magneto-optical trap, and has a broad range of potential applications.

  5. Classical Trace Anomaly

    OpenAIRE

    Farhoudi, M.

    1995-01-01

    We seek an analogy of the mathematical form of the alternative form of Einstein's field equations for Lovelock's field equations. We find that the price for this analogy is to accept the existence of the trace anomaly of the energy-momentum tensor even in classical treatments. As an example, we take this analogy to any generic second order Lagrangian and exactly derive the trace anomaly relation suggested by Duff. This indicates that an intrinsic reason for the existence of such a relation sh...

  6. TCP Packet Trace Analysis. M.S. Thesis

    Science.gov (United States)

    Shepard, Timothy J.

    1991-01-01

    Examination of a trace of packets collected from the network is often the only method available for diagnosing protocol performance problems in computer networks. This thesis explores the use of packet traces to diagnose performance problems of the transport protocol TCP. Unfortunately, manual examination of these traces can be so tedious that effective analysis is not possible. The primary contribution of this thesis is a graphical method of displaying the packet trace which greatly reduce, the tediousness of examining a packet trace. The graphical method is demonstrated by the examination of some packet traces of typical TCP connections. The performance of two different implementations of TCP sending data across a particular network path is compared. Traces many thousands of packets long are used to demonstrate how effectively the graphical method simplifies examination of long complicated traces. In the comparison of the two TCP implementations, the burstiness of the TCP transmitter appeared to be related to the achieved throughput. A method of quantifying this burstiness is presented and its possible relevance to understanding the performance of TCP is discussed.

  7. TRACING EFFICIENT PATH USING WEB PATH TRACING

    Directory of Open Access Journals (Sweden)

    L.K. Joshila Grace

    2014-01-01

    Full Text Available In the fast improving society, people depend on online purchase of goods than spending time physically. So there are lots of resources emerged for this online buying and selling of materials. Efficient and attractive web sites would be the best to sell the goods to people. To know whether a web site is reaching the mind of the customers or not, a high speed analysis is done periodically by the web developers. This works helps for the web site developers in knowing the weaker and stronger section of their web site. Parameters like frequency and utility are used for quantitative and qualitative analysis respectively. Addition to this down loads, book marks and the like/dislike of the particular web site is also considered. A new web path trace tree structure is implemented. A mathematical implementation is done to predict the efficient pattern used by the web site visitors.

  8. Effect of increasing amounts of straw on pigs' explorative behaviour

    DEFF Research Database (Denmark)

    Jensen, Margit Bak; Herskin, Mette S.; Forkman, Björn;

    2015-01-01

    According to European legislation, pigs must have permanent access to sufficient quantity of materialto enable manipulation activities. However, few studies have quantified how much straw is needed tofulfil the requirements of growing pigs. We investigated the effect of increasing amount of straw...... on pigs’manipulation of the straw, and hypothesised that after a certain point increasing straw amount will nolonger increase oral manipulation further. From 30 to 80 kg live weight, pigs were housed in 90 groups of18 pigs in pens (5.48 m × 2.48 m) with partly slatted concrete floor and daily provided...... with fresh uncutstraw onto the solid part of the floor. Experimental treatments were 10, 80, 150, 220, 290, 360, 430 or500 g straw per pig and day. At 40 and 80 kg live weight, the time spent in oral manipulation of the strawby three focal pigs per pen (large, medium and small sized) were recorded along...

  9. Quantum discord bounds the amount of distributed entanglement.

    Science.gov (United States)

    Chuan, T K; Maillard, J; Modi, K; Paterek, T; Paternostro, M; Piani, M

    2012-08-17

    The ability to distribute quantum entanglement is a prerequisite for many fundamental tests of quantum theory and numerous quantum information protocols. Two distant parties can increase the amount of entanglement between them by means of quantum communication encoded in a carrier that is sent from one party to the other. Intriguingly, entanglement can be increased even when the exchanged carrier is not entangled with the parties. However, in light of the defining property of entanglement stating that it cannot increase under classical communication, the carrier must be quantum. Here we show that, in general, the increase of relative entropy of entanglement between two remote parties is bounded by the amount of nonclassical correlations of the carrier with the parties as quantified by the relative entropy of discord. We study implications of this bound, provide new examples of entanglement distribution via unentangled states, and put further limits on this phenomenon.

  10. Mode Gaussian beam tracing

    CERN Document Server

    Trofimov, M Yu; Kozitskiy, S B

    2015-01-01

    An adiabatic mode Helmholtz equation for 3D underwater sound propagation is developed. The Gaussian beam tracing in this case is constructed. The test calculations are carried out for the crosswedge benchmark and proved an excellent agreement with the source images method.

  11. Local Logics for Traces

    DEFF Research Database (Denmark)

    Walukiewicz, Igor

    2002-01-01

    The µ-calculus over dependence graph representation of traces is considered. It is shown that the plain µ-calculus cannot express all monadic second-order (MSO) properties of dependence graphs. Several extensions of the µ-calculus are presented and it is proved that these extensions are equivalent...

  12. Tracing Cultural Memory

    DEFF Research Database (Denmark)

    Wiegand, Frauke Katharina

    to Soweto’s Regina Mundi Church, this thesis analyses tourists’ snapshots at sites of memory and outlines their tracing activity in cultural memory. It draws on central concepts of actor - network theory and visual culture studies for a cross - disciplinary methodology to comprehend the collective...

  13. A first proposal for a general description model of forensic traces

    Science.gov (United States)

    Lindauer, Ina; Schäler, Martin; Vielhauer, Claus; Saake, Gunter; Hildebrandt, Mario

    2012-06-01

    In recent years, the amount of digitally captured traces at crime scenes increased rapidly. There are various kinds of such traces, like pick marks on locks, latent fingerprints on various surfaces as well as different micro traces. Those traces are different from each other not only in kind but also in which information they provide. Every kind of trace has its own properties (e.g., minutiae for fingerprints, or raking traces for locks) but there are also large amounts of metadata which all traces have in common like location, time and other additional information in relation to crime scenes. For selected types of crime scene traces, type-specific databases already exist, such as the ViCLAS for sexual offences, the IBIS for ballistic forensics or the AFIS for fingerprints. These existing forensic databases strongly differ in the trace description models. For forensic experts it would be beneficial to work with only one database capable of handling all possible forensic traces acquired at a crime scene. This is especially the case when different kinds of traces are interrelated (e.g., fingerprints and ballistic marks on a bullet casing). Unfortunately, current research on interrelated traces as well as general forensic data models and structures is not mature enough to build such an encompassing forensic database. Nevertheless, recent advances in the field of contact-less scanning make it possible to acquire different kinds of traces with the same device. Therefore the data of these traces is structured similarly what simplifies the design of a general forensic data model for different kinds of traces. In this paper we introduce a first common description model for different forensic trace types. Furthermore, we apply for selected trace types from the well established database schema development process the phases of transferring expert knowledge in the corresponding forensic fields into an extendible, database-driven, generalised forensic description model. The

  14. Trace Metals Derived from Electronic Cigarette (ECIG) Generated Aerosol: Potential Problem of ECIG Devices That Contain Nickel.

    Science.gov (United States)

    Palazzolo, Dominic L; Crow, Andrew P; Nelson, John M; Johnson, Robert A

    2016-01-01

    Introduction: ECIGs are currently under scrutiny concerning their safety, particularly in reference to the impact ECIG liquids (E-liquids) have on human health. One concern is that aerosolized E-liquids contain trace metals that could become trapped in respiratory tissues and induce pathology. Methods: To mimic this trapping, peristaltic pumps were used to generate and transport aerosol onto mixed cellulose ester (MCE) membranes where aluminum (Al), arsenic (As), cadmium (Cd), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn) were subsequently captured and quantified. The presence of trace metals on unexposed MCE membranes and on MCE membranes exposed to mainstream smoke served as control and comparison, respectively. The presence of these metals was also determined from the E-liquid before aerosolization and untouched by the ECIG device. All metals were quantified using ICP-MS. The ECIG core assembly was analyzed using scanning electron microscopy with elemental analysis capability. Results: The contents (μg) of Al, As, Cd, Cu, Fe, Mn, Ni, Pb, and Zn on control MCE membranes were 1.2 ± 0.2, 0.050 ± 0.002, 0.047 ± 0.003, 0.05 ± 0.01, 0.001 ± 0.001, 0.16 ± 0.04, 0.005 ± 0.003, 0.014 ± 0.006, and 0.09 ± 0.02, respectively. The contents of all trace metals on MCE membranes exposed to aerosol were similar to controls, except Ni which was significantly (p metals in E-liquid before aerosolization were negligible compared to amounts of aerosolized E-liquid, except for Fe (0.002 μg before and 0.001 μg after). Elemental analysis of the core assembly reveals the presence of several of these trace metals, especially Al, Fe, Ni, and Zn. Conclusions: In general, from the single ECIG-device/E-liquid combination used, the amount of trace metals from ECIG-generated aerosol are lower than in traditional mainstream smoke, Only Ni in the ECIG-generated aerosol was higher than control. The most probable source of Ni in this aerosol is the core

  15. Quantifying capital goods for waste landfilling

    DEFF Research Database (Denmark)

    Brogaard, Line Kai-Sørensen; Stentsøe, Steen; Willumsen, Hans Christian

    2013-01-01

    Materials and energy used for construction of a hill-type landfill of 4 million m3 were quantified in detail. The landfill is engineered with a liner and leachate collections system, as well as a gas collection and control system. Gravel and clay were the most common materials used, amounting...... to approximately 260 kg per tonne of waste landfilled. The environmental burdens from the extraction and manufacturing of the materials used in the landfill, as well as from the construction of the landfill, were modelled as potential environmental impacts. For example, the potential impact on global warming was 2.......5 kg carbon dioxide (CO2) equivalents or 0.32 milli person equivalents per tonne of waste. The potential impacts from the use of materials and construction of the landfill are low-to-insignificant compared with data reported in the literature on impact potentials of landfills in operation...

  16. Quantifying capital goods for waste incineration

    DEFF Research Database (Denmark)

    Brogaard, Line Kai-Sørensen; Riber, C.; Christensen, Thomas Højlund

    2013-01-01

    Materials and energy used for the construction of modern waste incineration plants were quantified. The data was collected from five incineration plants (72,000–240,000tonnes per year) built in Scandinavia (Norway, Finland and Denmark) between 2006 and 2012. Concrete for the buildings was the main...... of producing the materials used in the construction, steel for the building and the machinery contributed the most. The material and energy used for the construction corresponded to the emission of 7–14kg CO2 per tonne of waste combusted throughout the lifetime of the incineration plant. The assessment showed...... material used amounting to 19,000–26,000tonnes per plant. The quantification further included six main materials, electronic systems, cables and all transportation. The energy used for the actual on-site construction of the incinerators was in the range 4000–5000MWh. In terms of the environmental burden...

  17. Singular traces theory and applications

    CERN Document Server

    Sukochev, Fedor; Zanin, Dmitriy

    2012-01-01

    This text is the first complete study and monograph dedicated to singular traces. For mathematical readers the text offers, due to Nigel Kalton's contribution, a complete theory of traces on symmetrically normed ideals of compact operators. For mathematical physicists and other users of Connes' noncommutative geometry the text offers a complete reference to Dixmier traces and the deeper mathematical features of singular traces. An application section explores the consequences of these features, which previously were not discussed in general texts on noncommutative geometry.

  18. Quantifying resource use in computations

    NARCIS (Netherlands)

    van Son, R.J.J.H.

    2009-01-01

    It is currently not possible to quantify the resources needed to perform a computation. As a consequence, it is not possible to reliably evaluate the hardware resources needed for the application of algorithms or the running of programs. This is apparent in both computer science, for in- stance, in

  19. Quantifying resource use in computations

    NARCIS (Netherlands)

    van Son, R.J.J.H.

    2009-01-01

    It is currently not possible to quantify the resources needed to perform a computation. As a consequence, it is not possible to reliably evaluate the hardware resources needed for the application of algorithms or the running of programs. This is apparent in both computer science, for in- stance, in

  20. Mode Gaussian beam tracing

    Science.gov (United States)

    Trofimov, M. Yu.; Zakharenko, A. D.; Kozitskiy, S. B.

    2016-10-01

    A mode parabolic equation in the ray centered coordinates for 3D underwater sound propagation is developed. The Gaussian beam tracing in this case is constructed. The test calculations are carried out for the ASA wedge benchmark and proved an excellent agreement with the source images method in the case of cross-slope propagation. But in the cases of wave propagation at some angles to the cross-slope direction an account of mode interaction becomes necessary.

  1. Trace metal speciation and bioavailability in anaerobic digestion: A review.

    Science.gov (United States)

    Thanh, Pham Minh; Ketheesan, Balachandran; Yan, Zhou; Stuckey, David

    2016-01-01

    Trace metals are essential for the growth of anaerobic microorganisms, however, in practice they are often added to anaerobic digesters in excessive amounts, which can lead to inhibition. The concept of bioavailability of metals in anaerobic digestion has been poorly understood in the past, and a lack of deep understanding of the relationship between trace metal speciation and bioavailability can result in ineffective metal dosing strategies for anaerobic digesters. Sequential extraction schemes are useful for fractionating trace metals into their different forms, and metal sulfides can serve as a store and source for trace metals during anaerobic digestion, while natural/synthetic chelating agents (soluble microbial products-SMPs, extracellular polysaccharides-EPS, and EDTA/NTA) are capable of controlling trace metal bioavailability. Nevertheless, more work is needed to: investigate the speciation and bioavailability of Ca, Mg, Mn, W, and Se; compare the bioavailability of different forms of trace metals e.g. carbonates, sulfides, phosphates to different anaerobic trophic groups; determine what factors influence metal sulfide dissolution; investigate whether chelating agents can increase trace metal bioavailability; develop and adapt specialized analytical techniques, and; determine how trace metal dynamics change in an anaerobic membrane bioreactor (AnMBR).

  2. Quantifying Emergent Behavior of Autonomous Robots

    Directory of Open Access Journals (Sweden)

    Georg Martius

    2015-10-01

    Full Text Available Quantifying behaviors of robots which were generated autonomously from task-independent objective functions is an important prerequisite for objective comparisons of algorithms and movements of animals. The temporal sequence of such a behavior can be considered as a time series and hence complexity measures developed for time series are natural candidates for its quantification. The predictive information and the excess entropy are such complexity measures. They measure the amount of information the past contains about the future and thus quantify the nonrandom structure in the temporal sequence. However, when using these measures for systems with continuous states one has to deal with the fact that their values will depend on the resolution with which the systems states are observed. For deterministic systems both measures will diverge with increasing resolution. We therefore propose a new decomposition of the excess entropy in resolution dependent and resolution independent parts and discuss how they depend on the dimensionality of the dynamics, correlations and the noise level. For the practical estimation we propose to use estimates based on the correlation integral instead of the direct estimation of the mutual information based on next neighbor statistics because the latter allows less control of the scale dependencies. Using our algorithm we are able to show how autonomous learning generates behavior of increasing complexity with increasing learning duration.

  3. Anisotropic ray trace

    Science.gov (United States)

    Lam, Wai Sze Tiffany

    Optical components made of anisotropic materials, such as crystal polarizers and crystal waveplates, are widely used in many complex optical system, such as display systems, microlithography, biomedical imaging and many other optical systems, and induce more complex aberrations than optical components made of isotropic materials. The goal of this dissertation is to accurately simulate the performance of optical systems with anisotropic materials using polarization ray trace. This work extends the polarization ray tracing calculus to incorporate ray tracing through anisotropic materials, including uniaxial, biaxial and optically active materials. The 3D polarization ray tracing calculus is an invaluable tool for analyzing polarization properties of an optical system. The 3x3 polarization ray tracing P matrix developed for anisotropic ray trace assists tracking the 3D polarization transformations along a ray path with series of surfaces in an optical system. To better represent the anisotropic light-matter interactions, the definition of the P matrix is generalized to incorporate not only the polarization change at a refraction/reflection interface, but also the induced optical phase accumulation as light propagates through the anisotropic medium. This enables realistic modeling of crystalline polarization elements, such as crystal waveplates and crystal polarizers. The wavefront and polarization aberrations of these anisotropic components are more complex than those of isotropic optical components and can be evaluated from the resultant P matrix for each eigen-wavefront as well as for the overall image. One incident ray refracting or reflecting into an anisotropic medium produces two eigenpolarizations or eigenmodes propagating in different directions. The associated ray parameters of these modes necessary for the anisotropic ray trace are described in Chapter 2. The algorithms to calculate the P matrix from these ray parameters are described in Chapter 3 for

  4. Exoskeleton Heterogeneity in Crustaceans: Quantifying Compositional and Structural Variations Across Body Parts

    Science.gov (United States)

    Ulrich, R. N.; Mergelsberg, S. T.; Dove, P. M.

    2016-12-01

    Crustacean exoskeletons are a complex biocomposite of organic macromolecules and calcium carbonate minerals. The highly divergent functions and diverse morphologies of these biominerals across taxa raise the question of whether these differences are systematically reflected in exoskeleton composition and structure. Previous studies that investigated element concentrations in exoskeletons used spectroscopic methods. However, the findings were largely inconclusive because of analytical limitations and most studies concluded that magnesium, phosphorus, and other trace elements are mostly contained in the mineral fraction because concentrations in the organic framework could not be resolved. This experimental study was designed to quantify the distributions of Ca, P, Mg, and Sr in the mineral versus organic fractions of exoskeletons from the American Lobster (H. americanus), Dungeness Crab (M. magister), and Red Rock Crab (M. productus). Samples of exoskeleton from 10 body parts were collected in triplicate and dissolved using three procedures specific to extracting the 1) mineral, 2) protein, and 3) chitin phases separately. Chemical analyses of the resulting effluents using ICP-OES show the mineral fraction of the skeleton can contain significant amounts of mineralized Mg and P particularly for body parts associated with a significant difference in mineral structural ordering. The protein fraction contains more Mg and P than expected based on estimates from previous studies (Hild et al., 2008). While the element distributions vary greatly depending on the location, in body parts with thicker cuticle (e.g. claw) the mineral component appears to control overall composition. The findings have implications for paleoenvironmental reconstructions based upon exoskeleton composition. First, the chemical composition of an exoskeleton cannot be assumed constant across the different body parts of an entire organism. This is particularly true when the exoskeleton of the claw is

  5. Trace elements in oil shale. Progress report, 1979-1980

    Energy Technology Data Exchange (ETDEWEB)

    Chappell, W R

    1980-01-01

    The purpose of this research program is to understand the potential impact of an oil shale industry on environmental levels of trace contaminants in the region. The program involves a comprehensive study of the sources, release mechanisms, transport, fate, and effects of toxic trace chemicals, principally the trace elements, in an oil shale industry. The overall objective of the program is to evaluate the environmental and health consequences of the release of toxic trace elements by shale and oil production and use. The baseline geochemical survey shows that stable trace elements maps can be constructed for numerous elements and that the trends observed are related to geologic and climatic factors. Shale retorted by above-ground processes tends to be very homogeneous (both in space and in time) in trace element content. Leachate studies show that significant amounts of B, F, and Mo are released from retorted shales and while B and Mo are rapidly flushed out, F is not. On the other hand, As, Se, and most other trace elements are not present in significant quantities. Significant amounts of F and B are also found in leachates of raw shales. Very large concentrations of reduced sulfur species are found in leachates of processed shale. Very high levels of B and Mo are taken up in some plants growing on processed shale with and without soil cover. There is a tendency for some trace elements to associate with specific organic fractions, indicating that organic chelation or complexation may play an important role. Many of the so-called standard methods for analyzing trace elements in oil shale-related materials are inadequate. A sampling manual is being written for the environmental scientist and practicing engineer. A new combination of methods is developed for separating the minerals in oil shale into different density fractions. Microbial investigations have tentatively identified the existence of thiobacilli in oil shale materials such as leachates. (DC)

  6. Mineralogical controls on the partitioning of trace elements between smoke and ash during the combustion of tobacco

    Science.gov (United States)

    Stephens, W. E.; Calder, A.

    2003-04-01

    Tobacco smoke is a potential source of some toxic trace elements including inorganic carcinogens1,2. In order to understand the controls on trace elements in smoke and their potential toxic effects it is necessary to know their distribution between the various inorganic (mineral) and organic repositories in tobacco, the relative concentrations of these repositories, the effects of combustion on these repositories, and the role of particles in adsorbing and transporting trace elements. Few trace element data are available for any of these materials and the partitioning processes are poorly understood. We have applied Rietveld XRD to quantifying the major minerals the tobacco of all available cigarette references standards, as well as the most popular UK cigarette brands and a selection of international brands. Most common are calcium oxalate biominerals (up to 4% by dry weight), calcium carbonate, sylvite, and several silicate minerals typical of soils amounting to a few wt%. We have developed an accurate and rapid method for determining 23 trace elements in tobacco using polarised X-ray fluorescence spectrometry, and applied it to the same samples. Although the concentrations vary over about five orders of magnitude the abundance patterns for standards and brands are remarkably consistent. We present a model to account for these variations in which anthropogenic inputs of fertilisers, manufacturers’ additives and environmental pollution supplement natural sources based on soils and plant processes. Combustion of tobacco (400-900^oC) causes the oxalates (whewellite &weddellite) to decompose and other non-silicates react to form new phases such as fairchildite (K_2Ca(CO_3)_2) and arcanite (K_2SO_4). Ash amounts to ˜15% of the mass of unburned tobacco. Comparison of trace element concentrations in smoke with those in tobacco and ash indicates that a few metals, most notably Cd, may partition strongly into the smoke phase. It is noteworthy that Cd levels are higher

  7. Quantifying capital goods for waste incineration.

    Science.gov (United States)

    Brogaard, L K; Riber, C; Christensen, T H

    2013-06-01

    Materials and energy used for the construction of modern waste incineration plants were quantified. The data was collected from five incineration plants (72,000-240,000 tonnes per year) built in Scandinavia (Norway, Finland and Denmark) between 2006 and 2012. Concrete for the buildings was the main material used amounting to 19,000-26,000 tonnes per plant. The quantification further included six main materials, electronic systems, cables and all transportation. The energy used for the actual on-site construction of the incinerators was in the range 4000-5000 MW h. In terms of the environmental burden of producing the materials used in the construction, steel for the building and the machinery contributed the most. The material and energy used for the construction corresponded to the emission of 7-14 kg CO2 per tonne of waste combusted throughout the lifetime of the incineration plant. The assessment showed that, compared to data reported in the literature on direct emissions from the operation of incinerators, the environmental impacts caused by the construction of buildings and machinery (capital goods) could amount to 2-3% with respect to kg CO2 per tonne of waste combusted.

  8. Meditations on Quantified Constraint Satisfaction

    CERN Document Server

    Chen, Hubie

    2012-01-01

    The quantified constraint satisfaction problem (QCSP) is the problem of deciding, given a structure and a first-order prenex sentence whose quantifier-free part is the conjunction of atoms, whether or not the sentence holds on the structure. One obtains a family of problems by defining, for each structure B, the problem QCSP(B) to be the QCSP where the structure is fixed to be B. In this article, we offer a viewpoint on the research program of understanding the complexity of the problems QCSP(B) on finite structures. In particular, we propose and discuss a group of conjectures; throughout, we attempt to place the conjectures in relation to existing results and to emphasize open issues and potential research directions.

  9. Quantifier Elimination by Dependency Sequents

    CERN Document Server

    Goldberg, Eugene

    2012-01-01

    We consider the problem of existential quantifier elimination for Boolean formulas in Conjunctive Normal Form (CNF). We present a new method for solving this problem called Derivation of Dependency-Sequents (DDS). A Dependency-sequent (D-sequent) is used to record that a set of quantified variables is redundant under a partial assignment. We show that D-sequents can be resolved to obtain new, non-trivial D-sequents. We also show that DDS is compositional, i.e. if our input formula is a conjunction of independent formulas, DDS automatically recognizes and exploits this information. We introduce an algorithm based on DDS and present experimental results demonstrating its potential.

  10. Differential scanning calorimetry to quantify the stability of protein cages.

    Science.gov (United States)

    Zhang, Yu; Ardejani, Maziar S

    2015-01-01

    Differential scanning calorimetry (DSC) is an experimental technique through which the differences in amount of heat required to maintain equal temperature between a sample and a reference cell are measured at various temperatures. The quantified heat relates to the differences in apparent heat capacity of the analytes. The data from DSC studies will thereby provide direct information about the energetics of thermally induced processes in the sample. Here we present a detailed protocol to quantify the thermostability of protein cage, bacterioferritin (BFR), using differential scanning calorimetry.

  11. Quantifying and measuring cyber resiliency

    Science.gov (United States)

    Cybenko, George

    2016-05-01

    Cyber resliency has become an increasingly attractive research and operational concept in cyber security. While several metrics have been proposed for quantifying cyber resiliency, a considerable gap remains between those metrics and operationally measurable and meaningful concepts that can be empirically determined in a scientific manner. This paper describes a concrete notion of cyber resiliency that can be tailored to meet specific needs of organizations that seek to introduce resiliency into their assessment of their cyber security posture.

  12. Osteoporosis and trace elements

    DEFF Research Database (Denmark)

    Aaseth, J.; Boivin, G.; Andersen, Ole

    2012-01-01

    More than 200 million people are affected by osteoporosis worldwide, as estimated by 2 million annual hip fractures and other debilitating bone fractures (vertebrae compression and Colles' fractures). Osteoporosis is a multi-factorial disease with potential contributions from genetic, endocrine...... in new bone and results in a net gain in bone mass, but may be associated with a tissue of poor quality. Aluminum induces impairment of bone formation. Gallium and cadmium suppresses bone turnover. However, exact involvements of the trace elements in osteoporosis have not yet been fully clarified...

  13. On current trace problem

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The pricing of electricity trasmission requires determining how much use each generator is making of a transmission line and what is each generator's contribution to the system losses. Such problems cannot be solved by only using Kirchoff's laws. This paper proposes two current decomposition axioms based on which the theories and models are established for the current trace problem. To create an efficient algorithm the graph theory is employed. It is proved that there is no directed circuit in a directed current distribution graph. According to this theorem a very simple and efficient algorithm based on recursive elimination process is suggested. A simple example is used to explain the algorithm.

  14. Tracing Back The Botmaster

    Directory of Open Access Journals (Sweden)

    Sneha Leslie

    2014-12-01

    Full Text Available Nowadays, cyber-attacks from botnets are increasing at a faster rate than any other malware spread. Detecting the botmaster who commands the tasks has become more difficult. Most of the detecting methods are based on the features of any communication protocol or the history of the network traffic. In this paper, a rational approach is brought for the live detection of the botmaster in the internal network. The victim machine monitors its packets and compromises the bots in the network and finds the traces to the botmaster. This approach works independent of the structure of the botnet, and will be a better option for online detection of the botmaster

  15. Practical applications of trace minerals for dairy cattle.

    Science.gov (United States)

    Overton, T R; Yasui, T

    2014-02-01

    Trace minerals have critical roles in the key interrelated systems of immune function, oxidative metabolism, and energy metabolism in ruminants. To date, the primary trace elements of interest in diets for dairy cattle have included Zn, Cu, Mn, and Se although data also support potentially important roles of Cr, Co, and Fe in diets. Trace minerals such as Zn, Cu, Mn, and Se are essential with classically defined roles as components of key antioxidant enzymes and proteins. Available evidence indicates that these trace minerals can modulate aspects of oxidative metabolism and immune function in dairy cattle, particularly during the transition period and early lactation. Chromium has been shown to influence both immune function and energy metabolism of cattle; dairy cows fed Cr during the transition period and early lactation have evidence of improved immune function, increased milk production, and decreased cytological endometritis. Factors that complicate trace mineral nutrition at the farm level include the existence of a large number of antagonisms affecting bioavailability of individual trace minerals and uncertainty in terms of requirements under all physiological and management conditions; therefore, determining the optimum level and source of trace minerals under each specific situation continues to be a challenge. Typical factorial approaches to determine requirements for dairy cattle do not account for nuances in biological function observed with supplementation with various forms and amounts of trace minerals. Trace mineral nutrition modulates production, health, and reproduction in cattle although both formal meta-analysis and informal survey of the literature reveal substantial heterogeneity of response in these outcome variables. The industry has largely moved away from oxide-based programs toward sulfate-based programs; however, some evidence favors shifting supplementation strategies further toward more bioavailable forms of inorganic and organic trace

  16. Trace conditioning in insects – Keep the trace!

    Directory of Open Access Journals (Sweden)

    Kristina V Dylla

    2013-08-01

    Full Text Available Trace conditioning is a form of associative learning that can be induced by presenting a conditioned stimulus (CS and an unconditioned stimulus (US following each other, but separated by a temporal gap. This gap distinguishes trace conditioning from classical delay conditioning, where the CS and US overlap. To bridge the temporal gap between both stimuli and to form an association between CS and US in trace conditioning, the brain must keep a neural representation of the CS after its termination – a stimulus trace. Behavioral and physiological studies on trace and delay conditioning revealed similarities between the two forms of learning, like similar memory decay and similar odor identity perception in invertebrates. On the other hand differences were reported also, like the requirement of distinct brain structures in vertebrates or disparities in molecular mechanisms in both vertebrates and invertebrates. For example, in commonly used vertebrate conditioning paradigms the hippocampus is necessary for trace but not for delay conditioning, and Drosophila delay conditioning requires the Rutabaga adenylyl cyclase, which is dispensable in trace conditioning. It is still unknown how the brain encodes CS traces and how they are associated with a US in trace conditioning. Insects serve as powerful models to address the mechanisms underlying trace conditioning, due to their simple brain anatomy, behavioral accessibility and established methods of genetic interference. In this review we summarize the recent progress in insect trace conditioning on the behavioral and physiological level and emphasize similarities and differences compared to delay conditioning. Moreover, we examine proposed molecular and computational models and reassess different experimental approaches used for trace conditioning.

  17. Quantified Self: An Overview & the Development of a Universal Tracking Application

    OpenAIRE

    Robertsson, Lukas

    2014-01-01

    Quantified self is the concept of tracking, recording and analyzing various pieces of data about ourselves to discover previously unknown patterns. Quantified self can involve manually or automatically recording and tracking data, like the time spent asleep, heart rate, mood or the amount of coffee consumed, using technological tools. This thesis aims to describe the new form of self-tracking, called quantified self. This is performed by looking into the following topics: how the concept has ...

  18. Prediction of the bioavailability of minerals and trace elements in foods.

    OpenAIRE

    Wolters, M.G.E.

    1992-01-01

    Minerals and trace elements play essential roles in numerous biochemical and physiological processes in animals and man. A deficiency, an overdose or imbalances between minerals or trace elements will exert a negative effect on health. Generally, it is not the ingested dose of minerals and trace elements that is important to maintain balance, but rather the amount that is bioavailable (available for biological and biochemical processes in the organism). Several food components are able to for...

  19. Trace elements in brazilian soils; Micronutrientes nos solos do Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, Geraldo Cesar [Juiz de Fora Univ., MG (Brazil). Dept. de Geociencias

    1995-03-01

    A literature revision on trace elements (Zn, B, Mn, Mo, Cu, Fe, and Cl) in Brazilian soils was prepared, with special attention to the chemical form and range in the soil, extraction methods and correlation of the amount in soils with soil properties. 76 refs.

  20. A VLSI design for a trace-back Viterbi decoder

    Science.gov (United States)

    Truong, T. K.; Shih, Ming-Tang; Reed, Irving S.; Satorius, E. H.

    1992-01-01

    A systolic Viterbi decoder for convolutional codes is developed which uses the trace-back method to reduce the amount of data needed to be stored in registers. It is shown that this new algorithm requires a smaller chip size and achieves a faster decoding time than other existing methods.

  1. Interpretation of complexometric titration data: An intercomparison of methods for estimating models of trace metal complexation by natural organic ligands

    NARCIS (Netherlands)

    Pižeta, I.; Sander, S.G.; Hudson, R.J.M.; Omanovic, D.; Baars, O.; Barbeau, K.A.; Buck, K.N.; Bundy, R.M.; Carrasco, G.; Croot, P.L.; Garnier, C.; Gerringa, L.J.A.; Gledhill, M.; Hirose, K.; Kondo, Y.; Laglera, L.M.; Nuester, J.; Rijkenberg, M.J.A.; Takeda, S.; Twining, B.S.; Wells, M.

    2015-01-01

    With the common goal of more accurately and consistently quantifying ambient concentrations of free metal ions and natural organic ligands in aquatic ecosystems, researchers from 15 laboratories that routinely analyze trace metal speciation participated in an intercomparison of statistical methods

  2. Lidar Detection of Explosives Traces

    Directory of Open Access Journals (Sweden)

    Bobrovnikov Sergei M.

    2016-01-01

    Full Text Available The possibility of remote detection of traces of explosives using laser fragmentation/laser-induced fluorescence (LF/LIF is studied. Experimental data on the remote visualization of traces of trinitrotoluene (TNT, hexogen (RDX, trotyl-hexogen (Comp B, octogen (HMX, and tetryl with a scanning lidar detector of traces of nitrogen-containing explosives at a distance of 5 m are presented.

  3. 7 CFR 1421.304 - Payment amount.

    Science.gov (United States)

    2010-01-01

    ... 2012 Crop of Wheat, Barley, Oats, and Triticale § 1421.304 Payment amount. (a) The grazing payment rate... complete program application to CCC. For triticale, the grazing rate will be equal to the loan deficiency... three (3) similar farms. For triticale, the payment yield shall be the yield for wheat from three...

  4. Physician Fee Schedule National Payment Amount File

    Data.gov (United States)

    U.S. Department of Health & Human Services — The significant size of the Physician Fee Schedule Payment Amount File-National requires that database programs (e.g., Access, dBase, FoxPro, etc.) be used to read...

  5. Quantifying mixing using equilibrium reactions

    Science.gov (United States)

    Wheat, Philip M.; Posner, Jonathan D.

    2009-03-01

    A method of quantifying equilibrium reactions in a microchannel using a fluorometric reaction of Fluo-4 and Ca2+ ions is presented. Under the proper conditions, equilibrium reactions can be used to quantify fluid mixing without the challenges associated with constituent mixing measures such as limited imaging spatial resolution and viewing angle coupled with three-dimensional structure. Quantitative measurements of CaCl and calcium-indicating fluorescent dye Fluo-4 mixing are measured in Y-shaped microchannels. Reactant and product concentration distributions are modeled using Green's function solutions and a numerical solution to the advection-diffusion equation. Equilibrium reactions provide for an unambiguous, quantitative measure of mixing when the reactant concentrations are greater than 100 times their dissociation constant and the diffusivities are equal. At lower concentrations and for dissimilar diffusivities, the area averaged fluorescence signal reaches a maximum before the species have interdiffused, suggesting that reactant concentrations and diffusivities must be carefully selected to provide unambiguous, quantitative mixing measures. Fluorometric equilibrium reactions work over a wide range of pH and background concentrations such that they can be used for a wide variety of fluid mixing measures including industrial or microscale flows.

  6. Trace analysis of semiconductor materials

    CERN Document Server

    Cali, J Paul; Gordon, L

    1964-01-01

    Trace Analysis of Semiconductor Materials is a guidebook concerned with procedures of ultra-trace analysis. This book discusses six distinct techniques of trace analysis. These techniques are the most common and can be applied to various problems compared to other methods. Each of the four chapters basically includes an introduction to the principles and general statements. The theoretical basis for the technique involved is then briefly discussed. Practical applications of the techniques and the different instrumentations are explained. Then, the applications to trace analysis as pertaining

  7. Flow tracing based on current

    Institute of Scientific and Technical Information of China (English)

    蔡兴国; 曹海龙

    2001-01-01

    Analyses the flow tracing based on power flow, points out that the detachment of reactive power and active power is unrealiable and concludes that the current is the real basic of flow tracing,and proposes the new flow tracing model based on current, which devides the current into active current and reactive current, analyses the theory about the matrix to deal with the precision and realization of the flow tracing, and then proposes a new pricing model by fixed rate and marginal rate, which keeps not only economy information such as congestion cost in marginal cost based pricing, but also benefits to make both ends meet.

  8. Quantifying capital goods for biological treatment of organic waste.

    Science.gov (United States)

    Brogaard, Line K; Petersen, Per H; Nielsen, Peter D; Christensen, Thomas H

    2015-02-01

    Materials and energy used for construction of anaerobic digestion (AD) and windrow composting plants were quantified in detail. The two technologies were quantified in collaboration with consultants and producers of the parts used to construct the plants. The composting plants were quantified based on the different sizes for the three different types of waste (garden and park waste, food waste and sludge from wastewater treatment) in amounts of 10,000 or 50,000 tonnes per year. The AD plant was quantified for a capacity of 80,000 tonnes per year. Concrete and steel for the tanks were the main materials for the AD plant. For the composting plants, gravel and concrete slabs for the pavement were used in large amounts. To frame the quantification, environmental impact assessments (EIAs) showed that the steel used for tanks at the AD plant and the concrete slabs at the composting plants made the highest contribution to Global Warming. The total impact on Global Warming from the capital goods compared to the operation reported in the literature on the AD plant showed an insignificant contribution of 1-2%. For the composting plants, the capital goods accounted for 10-22% of the total impact on Global Warming from composting.

  9. On current trace problem

    Institute of Scientific and Technical Information of China (English)

    王锡凡; 王秀丽

    2000-01-01

    The pricing of electricity trasmission requires determining how much use each generator is making of a transmission line and what is each generator’s contribution to the system losses. Such problems cannot be solved by only using Kirchoff’s laws. This paper proposes two current decomposition axioms based on which the theories and models are established for the current trace problem. To create an efficient algorithm the graph theory is employed. It is proved that there is no directed circuit in a directed current distribution graph. According to this theorem a very simple and efficient algorithm based on recursive elimination process is suggested. A simple example is used to explain the algorithm .

  10. Tracing Cultural Memory

    DEFF Research Database (Denmark)

    Wiegand, Frauke Katharina

    We encounter, relate to and make use of our past and that of others in multifarious and increasingly mobile ways. Tourism is one of the main paths for encountering sites of memory. This thesis examines tourists’ creative appropriations of sites of memory – the objects and future memories inspired...... by their encounters – to address a question that thirty years of ground - breaking research into memory has not yet sufficiently answered: What can we learn about the dynamics of cultural memory by examining mundane accounts of touristic encounters with sites of memory? From Blaavand Beach in Western Denmark...... to Soweto’s Regina Mundi Church, this thesis analyses tourists’ snapshots at sites of memory and outlines their tracing activity in cultural memory. It draws on central concepts of actor - network theory and visual culture studies for a cross - disciplinary methodology to comprehend the collective...

  11. Accelerator mass spectrometry for quantitative in vivo tracing

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, J S

    2005-04-19

    Accelerator mass spectrometry (AMS) counts individual rare, usually radio-, isotopes such as radiocarbon at high efficiency and specificity in milligram-sized samples. AMS traces very low chemical doses ({micro}g) and radiative doses (100 Bq) of isotope labeled compounds in animal models and directly in humans for pharmaceutical, nutritional, or toxicological research. Absorption, metabolism, distribution, binding, and elimination are all quantifiable with high precision after appropriate sample definition.

  12. Analysis of trace elements in opal using PIXE

    Energy Technology Data Exchange (ETDEWEB)

    Hinrichs, Ruth, E-mail: ruth.hinrichs@ufrgs.br [Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS (Brazil); Programa de Pós-graduação em Física, UFRGS, Porto Alegre, RS (Brazil); Bertol, A.P.L. [Programa de Pós-graduação em Física, UFRGS, Porto Alegre, RS (Brazil); Vasconcellos, M.A.Z. [Programa de Pós-graduação em Física, UFRGS, Porto Alegre, RS (Brazil); Instituto de Física, UFRGS, Porto Alegre, RS (Brazil)

    2015-11-15

    Particle induced X-ray emission (PIXE) analysis is particularly important for the analysis of trace elements of precious samples, being one of the few methods to determine elements with ppm concentration that does not affect sample integrity. A PIXE methodology for trace element analysis in opal was developed. To avoid detector count saturation due to the high number of Si-Kα X-rays generated in the sample, several filters were employed to optimize the reduction of the Si-Kα signal, while maintaining acceptable intensities of the other relevant X-ray lines. Two proton beam energies were tested, to establish the signal to noise ratio in different X-ray energies. Spectra were fitted with the software GUPIX, using a matrix composition determined with electron beam excited energy dispersive X-ray spectrometry. Above the energy of the silicon X-ray, several trace elements were quantified.

  13. Blast densification: A proposed methodology to quantify the amount of densification required to prevent liquefaction and flow in sandy soils

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Vega-Posada

    2016-01-01

    Full Text Available Este trabajo presenta una metodología para cuantificar el grado de densificación por explosivos o número de detonaciones requeridos para prevenir licuación y flujo en suelos arenosos sueltos y saturados, en un determinado proyecto. La metodología propuesta está basada en los conceptos de estado crítico de mecánica de suelos, y el número de detonaciones se escoge, de tal manera, que el estado final de esfuerzos del horizonte dinamitado, se localice por debajo de la línea de estado crítico del suelo, donde se espera una respuesta dilatante. Se presentan y utilizan los resultados obtenidos de ensayos de campo y laboratorio de un programa de densificación con explosivos en un relleno sanitario localizado en Carolina del Sur, Estados Unidos, con el objeto de evaluar el enfoque propuesto. Se presenta un ejemplo detallado paso a paso con éste propósito. Esta metodología puede proveer a ingenieros una manera racional de estimar que tanto mejoramiento se requiere en el suelo para alcanzar las condiciones de diseño de un proyecto en particular, así como los costos asociados a éste mejoramiento.

  14. Trace elements in termites by PIXE analysis

    Science.gov (United States)

    Yoshimura, T.; Kagemori, N.; Kawai, S.; Sera, K.; Futatsugawa, S.

    2002-04-01

    Trace elements in a Japanese subterranean xylophagous termite, Coptotermes formosanus Shiraki, were analyzed by the PIXE method. The total amount of the 14 predominant elements out of 27 detected in an intact termite was higher in a soldier termite (23 000 μg/g) than in a worker termite (10 000 μg/g). A block of wood ( Pinus densiflora Sieb. et Zucc.) for termite feed had a much lower concentration (3600 μg/g) compared with that in an intact termite. This probably relates the functional bio-condensation and/or bio-recycling of trace elements in C. formosanus. When a termite was separated into three anatomical parts, head, degutted body and gut, the worker gut contained the highest total amount of the 14 predominant measured elements (31 000 μg/g). This might be correlated with the higher activity of food digestion and energy production in the worker gut. Moreover, the mandible of the soldier head, with an exoskeleton that is intensely hardened, showed a preferential distribution of Mn and Fe. These results suggest that the characteristic localization of elements will be closely related to the functional role of the individual anatomical part of C. formosanus.

  15. Trace elements in termites by PIXE analysis

    Energy Technology Data Exchange (ETDEWEB)

    Yoshimura, T. E-mail: tsuyoshi@termite.kuwri.kyoto-u.ac.jp; Kagemori, N.; Kawai, S.; Sera, K.; Futatsugawa, S

    2002-04-01

    Trace elements in a Japanese subterranean xylophagous termite, Coptotermes formosanus Shiraki, were analyzed by the PIXE method. The total amount of the 14 predominant elements out of 27 detected in an intact termite was higher in a soldier termite (23 000 {mu}g/g) than in a worker termite (10 000 {mu}g/g). A block of wood (Pinus densiflora Sieb. et Zucc.) for termite feed had a much lower concentration (3600 {mu}g/g) compared with that in an intact termite. This probably relates the functional bio-condensation and/or bio-recycling of trace elements in C. formosanus. When a termite was separated into three anatomical parts, head, degutted body and gut, the worker gut contained the highest total amount of the 14 predominant measured elements (31 000 {mu}g/g). This might be correlated with the higher activity of food digestion and energy production in the worker gut. Moreover, the mandible of the soldier head, with an exoskeleton that is intensely hardened, showed a preferential distribution of Mn and Fe. These results suggest that the characteristic localization of elements will be closely related to the functional role of the individual anatomical part of C. formosanus.

  16. Lexical NP and VP quantifiers in Bulgarian

    Directory of Open Access Journals (Sweden)

    Kristina Kalpakchieva

    2015-11-01

    Full Text Available Lexical NP and VP quantifiers in Bulgarian The paper focuses on uniqueness, existential and universal quantification within the Bulgarian noun and verb phrase. Quantifiers scope is considered with respect to whether the quantifiers are used alone or in a group with other expressions. Another factor that affects the strength of quantifiers is the expression’s containing additional specifying functions or setting some circumstance or condition. Quantifiers within the verb phrase are particularly strongly affected by other conditions, while quantifiers within the subject NP have a broad scope and are not affected by the additional conditions of the situation described.

  17. Quantifying Resource Use in Computations

    CERN Document Server

    van Son, R J J H

    2009-01-01

    It is currently not possible to quantify the resources needed to perform a computation. As a consequence, it is not possible to reliably evaluate the hardware resources needed for the application of algorithms or the running of programs. This is apparent in both computer science, for instance, in cryptanalysis, and in neuroscience, for instance, comparative neuro-anatomy. A System versus Environment game formalism is proposed based on Computability Logic that allows to define a computational work function that describes the theoretical and physical resources needed to perform any purely algorithmic computation. Within this formalism, the cost of a computation is defined as the sum of information storage over the steps of the computation. The size of the computational device, eg, the action table of a Universal Turing Machine, the number of transistors in silicon, or the number and complexity of synapses in a neural net, is explicitly included in the computational cost. The proposed cost function leads in a na...

  18. Quantifying and simulating human sensation

    DEFF Research Database (Denmark)

    Quantifying and simulating human sensation – relating science and technology of indoor climate research Abstract In his doctoral thesis from 1970 civil engineer Povl Ole Fanger proposed that the understanding of indoor climate should focus on the comfort of the individual rather than averaged...... archival material related to Lund Madsen’s efforts are preserved at the Technical University of Denmark and I have used these artefacts as the point of departure for my investigation. In this paper I will examine which factors the researchers perceived as important for human indoor comfort and how...... this understanding of human sensation was adjusted to technology. I will look into the construction of the equipment, what it measures and the relationship between theory, equipment and tradition....

  19. Estimation of Fluorescent Dye Amount in Tracer Dye Test

    Science.gov (United States)

    Pekkan, Emrah; Balkan, Erman; Balkan, Emir

    2015-04-01

    Karstic groundwater is more influenced by human than the groundwater that disperse in pores. On the other hand karstic groundwater resources, in addition to providing agricultural needs, livestock breeding, drinking and domestic water in most of the months of the year, they also supply drinking water to the wild life at high altitudes. Therefore sustainability and hydrogeological investigation of karstic resources is critical. Tracing techniques are widely used in hydrologic and hydrogeologic studies to determine water storage, flow rate, direction and protection area of groundwater resources. Karanfil Mountain (2800 m), located in Adana, Turkey, is one of the karstic recharge areas of the natural springs spread around its periphery. During explorations of the caves of Karanfil mountain, a 600 m deep cave was found by the Turkish and Polish cavers. At the bottom of the cave there is an underground river with a flow rate of approximately 0.5 m3/s during August 2014. The main spring is located 8 km far from the cave's entrance and its mean flow rate changes between 3.4 m3/s and 0.21 m3/s in March and September respectively according to a flowrate observation station of Directorate of Water Works of Turkey. As such frequent storms, snowmelt and normal seasonal variations in rainfall have a significant and rapid effect on the volume of this main spring resource. The objective of our research is to determine and estimate dye amount before its application on the field inspired from the previously literature on the subject. This estimation is intended to provide a preliminary application of a tracer test of a karstic system. In this study dye injection, inlet point will be an underground river located inside the cave and the observation station will be the spring that is approximately 8 km far from the cave entrance. On the other hand there is 600 meter elevation difference between cave entrance and outlet spring. In this test Rodamin-WT will be used as tracer and the

  20. Tracing The Largest Seasonal Migration on Earth

    CERN Document Server

    Wang, Xianwen; Mao, Wenli; Hu, Zhigang; Gu, Li

    2014-01-01

    It is estimated that over 3.6 billion passengers are travelling during the Chinese Spring Festival travel season. They leave their working cities and return their hometowns to enjoy annual family time, and back to cities after the holiday. In this study, with the massive location-based data collected from millions of smartphone users, we propose a novel method to trace the migration flow and explore the migration patterns of Chinese people. From the temporal perspective, we explore the migration trend over time during a 34-days period, about half a month before and after the Spring Festival. From the spatial perspective, the migration directions and routes are estimated and quantified, and the migration flow is visualized. The spatial range of influence of developed regions could be reflected with the destinations of migration, the migration destinations and originations have obvious characteristic of geographical proximity.

  1. Analysis of the tracing problem

    Institute of Scientific and Technical Information of China (English)

    Nanfeng Jie; Hui Wang; YunqingSun

    2005-01-01

    Here the tracing problems are researched from two thoroughly different approaches: calculus method and numerical analysis. Generally speaking, the calculus method give a universal qualitative way to deal with such kind of problem, but the numerical analysis method can offer more further quantitative result for such kind of problem. Our research shows the detail results of application of these two methods in tracing problem.

  2. Discourse Tracing as Qualitative Practice

    Science.gov (United States)

    LeGreco, Marianne; Tracy, Sarah J.

    2009-01-01

    This article introduces a qualitative research method called "discourse tracing". Discourse tracing draws from contributions made by ethnographers, discourse critics, case study scholars, and process tracers. The approach offers new insights and an attendant language about how we engage in research designed specifically for the…

  3. Removal of trace organics by anaerobic membrane bioreactors.

    Science.gov (United States)

    Monsalvo, Victor M; McDonald, James A; Khan, Stuart J; Le-Clech, Pierre

    2014-02-01

    The biological removal of 38 trace organics (pharmaceuticals, endocrine disruptors, personal care products and pesticides) was studied in an anaerobic membrane bioreactor (AnMBR). This work presents complete information on the different removal mechanisms involved in the removal of trace organics in this process. In particular, it is focused on advanced characterization of the relative amount of TO accumulated within the fouling layers formed on the membranes. The results show that only 9 out of 38 compounds were removed by more than 90% while 23 compounds were removed by less than 50%. These compounds are therefore removed in an AnMBR biologically and partially adsorbed and retained by flocs and the deposition developed on the membranes, respectively. A total amount of 288 mg of trace organics was retained per m(2) of membrane, which were distributed along the different fouling layers. Among the trace organics analyzed, 17α-ethynylestradiol, estrone, octylphenol and bisphenol A were the most retained by the fouling layers. Among the fouling layers deposited on the membranes, the non-readily detachable layer has been identified as the main barrier for trace organics.

  4. Quantifying and Mapping Global Data Poverty.

    Directory of Open Access Journals (Sweden)

    Mathias Leidig

    Full Text Available Digital information technologies, such as the Internet, mobile phones and social media, provide vast amounts of data for decision-making and resource management. However, access to these technologies, as well as their associated software and training materials, is not evenly distributed: since the 1990s there has been concern about a "Digital Divide" between the data-rich and the data-poor. We present an innovative metric for evaluating international variations in access to digital data: the Data Poverty Index (DPI. The DPI is based on Internet speeds, numbers of computer owners and Internet users, mobile phone ownership and network coverage, as well as provision of higher education. The datasets used to produce the DPI are provided annually for almost all the countries of the world and can be freely downloaded. The index that we present in this 'proof of concept' study is the first to quantify and visualise the problem of global data poverty, using the most recent datasets, for 2013. The effects of severe data poverty, particularly limited access to geoinformatic data, free software and online training materials, are discussed in the context of sustainable development and disaster risk reduction. The DPI highlights countries where support is needed for improving access to the Internet and for the provision of training in geoinfomatics. We conclude that the DPI is of value as a potential metric for monitoring the Sustainable Development Goals of the Sendai Framework for Disaster Risk Reduction.

  5. Quantifying and Mapping Global Data Poverty.

    Science.gov (United States)

    Leidig, Mathias; Teeuw, Richard M

    2015-01-01

    Digital information technologies, such as the Internet, mobile phones and social media, provide vast amounts of data for decision-making and resource management. However, access to these technologies, as well as their associated software and training materials, is not evenly distributed: since the 1990s there has been concern about a "Digital Divide" between the data-rich and the data-poor. We present an innovative metric for evaluating international variations in access to digital data: the Data Poverty Index (DPI). The DPI is based on Internet speeds, numbers of computer owners and Internet users, mobile phone ownership and network coverage, as well as provision of higher education. The datasets used to produce the DPI are provided annually for almost all the countries of the world and can be freely downloaded. The index that we present in this 'proof of concept' study is the first to quantify and visualise the problem of global data poverty, using the most recent datasets, for 2013. The effects of severe data poverty, particularly limited access to geoinformatic data, free software and online training materials, are discussed in the context of sustainable development and disaster risk reduction. The DPI highlights countries where support is needed for improving access to the Internet and for the provision of training in geoinfomatics. We conclude that the DPI is of value as a potential metric for monitoring the Sustainable Development Goals of the Sendai Framework for Disaster Risk Reduction.

  6. Quantifying Supply Risk at a Cellulosic Biorefinery

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Jason K.; Jacobson, Jacob J.; Cafferty, Kara G.; Lamers, Patrick; Roni, Mohammad S.

    2015-07-01

    In order to increase the sustainability and security of the nation’s energy supply, the U.S. Department of Energy through its Bioenergy Technology Office has set a vision for one billion tons of biomass to be processed for renewable energy and bioproducts annually by the year 2030. The Renewable Fuels Standard limits the amount of corn grain that can be used in ethanol conversion sold in the U.S, which is already at its maximum. Therefore making the DOE’s vision a reality requires significant growth in the advanced biofuels industry where currently three cellulosic biorefineries convert cellulosic biomass to ethanol. Risk mitigation is central to growing the industry beyond its infancy to a level necessary to achieve the DOE vision. This paper focuses on reducing the supply risk that faces a firm that owns a cellulosic biorefinery. It uses risk theory and simulation modeling to build a risk assessment model based on causal relationships of underlying, uncertain, supply driving variables. Using the model the paper quantifies supply risk reduction achieved by converting the supply chain from a conventional supply system (bales and trucks) to an advanced supply system (depots, pellets, and trains). Results imply that the advanced supply system reduces supply system risk, defined as the probability of a unit cost overrun, from 83% in the conventional system to 4% in the advanced system. Reducing cost risk in this nascent industry improves the odds of realizing desired growth.

  7. Quantifying and Mapping Global Data Poverty

    Science.gov (United States)

    2015-01-01

    Digital information technologies, such as the Internet, mobile phones and social media, provide vast amounts of data for decision-making and resource management. However, access to these technologies, as well as their associated software and training materials, is not evenly distributed: since the 1990s there has been concern about a "Digital Divide" between the data-rich and the data-poor. We present an innovative metric for evaluating international variations in access to digital data: the Data Poverty Index (DPI). The DPI is based on Internet speeds, numbers of computer owners and Internet users, mobile phone ownership and network coverage, as well as provision of higher education. The datasets used to produce the DPI are provided annually for almost all the countries of the world and can be freely downloaded. The index that we present in this ‘proof of concept’ study is the first to quantify and visualise the problem of global data poverty, using the most recent datasets, for 2013. The effects of severe data poverty, particularly limited access to geoinformatic data, free software and online training materials, are discussed in the context of sustainable development and disaster risk reduction. The DPI highlights countries where support is needed for improving access to the Internet and for the provision of training in geoinfomatics. We conclude that the DPI is of value as a potential metric for monitoring the Sustainable Development Goals of the Sendai Framework for Disaster Risk Reduction. PMID:26560884

  8. Quantifying capital goods for waste landfilling.

    Science.gov (United States)

    Brogaard, Line K; Stentsøe, Steen; Willumsen, Hans Christian; Christensen, Thomas H

    2013-06-01

    Materials and energy used for construction of a hill-type landfill of 4 million m(3) were quantified in detail. The landfill is engineered with a liner and leachate collections system, as well as a gas collection and control system. Gravel and clay were the most common materials used, amounting to approximately 260 kg per tonne of waste landfilled. The environmental burdens from the extraction and manufacturing of the materials used in the landfill, as well as from the construction of the landfill, were modelled as potential environmental impacts. For example, the potential impact on global warming was 2.5 kg carbon dioxide (CO2) equivalents or 0.32 milli person equivalents per tonne of waste. The potential impacts from the use of materials and construction of the landfill are low-to-insignificant compared with data reported in the literature on impact potentials of landfills in operation. The construction of the landfill is only a significant contributor to the impact of resource depletion owing to the high use of gravel and steel.

  9. Asteroid Geophysics and Quantifying the Impact Hazard

    Science.gov (United States)

    Sears, D.; Wooden, D. H.; Korycanksy, D. G.

    2015-01-01

    Probably the major challenge in understanding, quantifying, and mitigating the effects of an impact on Earth is understanding the nature of the impactor. Of the roughly 25 meteorite craters on the Earth that have associated meteorites, all but one was produced by an iron meteorite and only one was produced by a stony meteorite. Equally important, even meteorites of a given chemical class produce a wide variety of behavior in the atmosphere. This is because they show considerable diversity in their mechanical properties which have a profound influence on the behavior of meteorites during atmospheric passage. Some stony meteorites are weak and do not reach the surface or reach the surface as thousands of relatively harmless pieces. Some stony meteorites roll into a maximum drag configuration and are strong enough to remain intact so a large single object reaches the surface. Others have high concentrations of water that may facilitate disruption. However, while meteorite falls and meteorites provide invaluable information on the physical nature of the objects entering the atmosphere, there are many unknowns concerning size and scale that can only be determined by from the pre-atmospheric properties of the asteroids. Their internal structure, their thermal properties, their internal strength and composition, will all play a role in determining the behavior of the object as it passes through the atmosphere, whether it produces an airblast and at what height, and the nature of the impact and amount and distribution of ejecta.

  10. Quantifying Evaporation in a Permeable Pavement System

    Science.gov (United States)

    Studies quantifying evaporation from permeable pavement systems are limited to a few laboratory studies and one field application. This research quantifies evaporation for a larger-scale field application by measuring the water balance from lined permeable pavement sections. Th...

  11. The SEGUE K Giant Survey. III. Quantifying Galactic Halo Substructure

    CERN Document Server

    Janesh, William; Ma, Zhibo; Harding, Paul; Rockosi, Constance; Starkenburg, Else; Xue, Xiang Xiang; Rix, Hans-Walter; Beers, Timothy C; Johnson, Jennifer; Lee, Young Sun; Schneider, Donald P

    2015-01-01

    We statistically quantify the amount of substructure in the Milky Way stellar halo using a sample of 4568 halo K giant stars at Galactocentric distances ranging over 5-125 kpc. These stars have been selected photometrically and confirmed spectroscopically as K giants from the Sloan Digital Sky Survey's SEGUE project. We use a position-velocity clustering estimator (the 4distance) and a smooth stellar halo model to quantify the amount of substructure in the halo. Overall, we find that the halo as a whole is highly structured, and confirm earlier work using BHB stars which showed that there is an increasing amount of substructure with increasing Galactocentric radius. In addition, we find that the amount of substructure in the halo increases with increasing metallicity, and that the K giant sample shows significantly stronger substructure than the BHB stars, which only sample the most metal poor stars. Using a friends-of-friends algorithm to identify groups, we find that a large fraction ($\\sim 33\\%$) of the st...

  12. Mapping the Natchez Trace Parkway

    Science.gov (United States)

    Rangoonwala, Amina; Bannister, Terri; Ramsey, Elijah W.

    2011-01-01

    Based on a National Park Service (NPS) landcover classification, a landcover map of the 715-km (444-mile) NPS Natchez Trace Parkway (hereafter referred to as the "Parkway") was created. The NPS landcover classification followed National Vegetation Classification (NVC) protocols. The landcover map, which extended the initial landcover classification to the entire Parkway, was based on color-infrared photography converted to 1-m raster-based digital orthophoto quarter quadrangles, according to U.S. Geological Survey mapping standards. Our goal was to include as many alliance classes as possible in the Parkway landcover map. To reach this goal while maintaining a consistent and quantifiable map product throughout the Parkway extent, a mapping strategy was implemented based on the migration of class-based spectral textural signatures and the congruent progressive refinement of those class signatures along the Parkway. Progressive refinement provided consistent mapping by evaluating the spectral textural distinctiveness of the alliance-association classes, and where necessary, introducing new map classes along the Parkway. By following this mapping strategy, the use of raster-based image processing and geographic information system analyses for the map production provided a quantitative and reproducible product. Although field-site classification data were severely limited, the combination of spectral migration of class membership along the Parkway and the progressive classification strategy produced an organization of alliances that was internally highly consistent. The organization resulted from the natural patterns or alignments of spectral variance and the determination of those spectral patterns that were compositionally similar in the dominant species as NVC alliances. Overall, the mapped landcovers represented the existent spectral textural patterns that defined and encompassed the complex variety of compositional alliances and associations of the Parkway. Based

  13. Quantifier Scope in Categorical Compositional Distributional Semantics

    Directory of Open Access Journals (Sweden)

    Mehrnoosh Sadrzadeh

    2016-08-01

    Full Text Available In previous work with J. Hedges, we formalised a generalised quantifiers theory of natural language in categorical compositional distributional semantics with the help of bialgebras. In this paper, we show how quantifier scope ambiguity can be represented in that setting and how this representation can be generalised to branching quantifiers.

  14. Mixing Formal and Informal Model Elements for Tracing Requirements

    DEFF Research Database (Denmark)

    Jastram, Michael; Hallerstede, Stefan; Ladenberger, Lukas

    2011-01-01

    a system for traceability with a state-based formal method that supports refinement. We do not require all specification elements to be modelled formally and support incremental incorporation of new specification elements into the formal model. Refinement is used to deal with larger amounts of requirements......Tracing between informal requirements and formal models is challenging. A method for such tracing should permit to deal efficiently with changes to both the requirements and the model. A particular challenge is posed by the persisting interplay of formal and informal elements. In this paper, we...

  15. Trace elements in oil shale. Progress report, 1976--1979

    Energy Technology Data Exchange (ETDEWEB)

    Chappell, W.R.

    1979-01-01

    The overall objective of the program is to evaluate the environmental and health consequences of the release of toxic trace elements (As, B, F, Mo, Se) by shale oil production and use. Some of the particularly significant results are: The baseline geochemical survey shows that stable trace elements maps can be constructed for numerous elements and that the trends observed are related to geologic and climatic factors. Shale retorted by above-ground processes tends to be very homogeneous (both in space and in time) in trace element content. This implies that the number of analytical determinations required of processed shales is not large. Leachate studies show that significant amounts of B, F, And Mo are released from retorted shales and while B and Mo are rapidly flushed out, F is not. On the other hand, As, Se, and most other trace elements ae not present in significant quantities. Significant amounts of F and B are also found in leachates of raw shales. Very large concentrations of reduced sulfur species are found in leachates of processed shale. Upon oxidation a drastic lowering in pH is observed. Preliminary data indicates that this oxidation is catalyzed by bacteria. Very high levels of B and Mo are taken up in some plants growing on processed shale with and without soil cover. These amounts depend upon the process and various site specific characteristics. In general, the amounts taken up decrease with increasing soil cover. On the other hand, we have not observed significant uptake of As, Se, and F into plants. There is a tendency for some trace elements to associate with specific organic fractions, indicating that organic chelation or complexation may play an important role. In particular, most of the Cd, Se, and Cr in shale oil is associated with the organic fraction containing most of the nitrogen-containing compounds.

  16. Trace elements induce predominance among methanogenic activity in anaerobic digestion

    Directory of Open Access Journals (Sweden)

    Babett Wintsche

    2016-12-01

    Full Text Available Trace elements play an essential role in all organisms due to their functions in enzyme complexes. In anaerobic digesters, control and supplementation of trace elements lead to stable and more efficient methane production processes while trace element deficits cause process imbalances. However, the underlying metabolic mechanisms and the adaptation of the affected microbial communities to such deficits are not yet fully understood. Here, we investigated the microbial community dynamics and resulting process changes induced by trace element deprivation. Two identical lab-scale continuous stirred tank reactors fed with distiller’s grains and supplemented with trace elements (cobalt, molybdenum, nickel, tungsten and a commercial iron additive were operated in parallel. After 72 weeks of identical operation, the feeding regime of one reactor was changed by omitting trace element supplements and reducing the amount of iron additive. Both reactors were operated for further 21 weeks. Various process parameters (biogas production and composition, total solids and volatile solids, trace element concentration, volatile fatty acids, total ammonium nitrogen, total organic acids/alkalinity ratio, and pH and the composition and activity of the microbial communities were monitored over the total experimental time. While the methane yield remained stable, the concentrations of hydrogen sulfide, total ammonia nitrogen, and acetate increased in the trace element-depleted reactor compared to the well-supplied control reactor. Methanosarcina and Methanoculleus dominated the methanogenic communities in both reactors. However, the activity ratio of these two genera was shown to depend on trace element supplementation explainable by different trace element requirements of their energy conservation systems. Methanosarcina dominated the well-supplied anaerobic digester, pointing to acetoclastic methanogenesis as the dominant methanogenic pathway. Under trace element

  17. Quantifying Cricket Fast Bowling Skill.

    Science.gov (United States)

    Feros, Simon A; Young, Warren B; O'Brien, Brendan J

    2017-09-27

    To evaluate the current evidence regarding the quantification of cricket fast bowling skill. Studies that assessed fast bowling skill (bowling speed and accuracy) were identified from searches in SPORTDiscus (EBSCO) in June 2017. The reference lists of identified papers were also examined for relevant investigations. Sixteen papers matched the inclusion criteria, and discrepancies in assessment procedures were evident. Differences in: test environment, pitch and cricket ball characteristics, the warm-up prior to test, test familiarisation procedures, permitted run-up lengths, bowling spell length, delivery sequence, test instructions, collection of bowling speed data, collection and reportage of bowling accuracy data were apparent throughout the literature. The reliability and sensitivity of fast bowling skill measures has rarely been reported across the literature. Only one study has attempted to assess the construct validity of their skill measures. There are several discrepancies in how fast bowling skill has been assessed and subsequently quantified in the literature to date. This is a problem, as comparisons between studies are often difficult. Therefore, a strong rationale exists for the creation of match-specific standardised fast bowling assessments that offer greater ecological validity while maintaining acceptable reliability and sensitivity of the skill measures. If prospective research can act on the proposed recommendations from this review, then coaches will be able to make more informed decisions surrounding player selection, talent identification, return to skill following injury, and the efficacy of short- and long-term training interventions for fast bowlers.

  18. Quantifying Periodicity in Omics Data

    Directory of Open Access Journals (Sweden)

    Cornelia eAmariei

    2014-08-01

    Full Text Available Oscillations play a significant role in biological systems, with many examples in the fast, ultradian, circadian, circalunar and yearly time domains. However, determining periodicity in such data can be problematic. There are a number of computational methods to identify the periodic components in large datasets, such as signal-to-noise based Fourier decomposition, Fisher's g-test and autocorrelation. However, the available methods assume a sinusoidal model and do not attempt to quantify the waveform shape and the presence of multiple periodicities, which provide vital clues in determining the underlying dynamics. Here, we developed a Fourier based measure that generates a de-noised waveform from multiple significant frequencies. This waveform is then correlated with the raw data from the respiratory oscillation found in yeast, to provide oscillation statistics including waveform metrics and multi-periods. The method is compared and contrasted to commonly used statistics. Moreover we show the utility of the program in the analysis of noisy datasets and other high-throughput analyses, such as metabolomics and flow cytometry, respectively.

  19. Quantifying the vitamin D economy.

    Science.gov (United States)

    Heaney, Robert P; Armas, Laura A G

    2015-01-01

    Vitamin D enters the body through multiple routes and in a variety of chemical forms. Utilization varies with input, demand, and genetics. Vitamin D and its metabolites are carried in the blood on a Gc protein that has three principal alleles with differing binding affinities and ethnic prevalences. Three major metabolites are produced, which act via two routes, endocrine and autocrine/paracrine, and in two compartments, extracellular and intracellular. Metabolic consumption is influenced by physiological controls, noxious stimuli, and tissue demand. When administered as a supplement, varying dosing schedules produce major differences in serum metabolite profiles. To understand vitamin D's role in human physiology, it is necessary both to identify the foregoing entities, mechanisms, and pathways and, specifically, to quantify them. This review was performed to delineate the principal entities and transitions involved in the vitamin D economy, summarize the status of present knowledge of the applicable rates and masses, draw inferences about functions that are implicit in these quantifications, and point out implications for the determination of adequacy.

  20. The role of clay in enhancing attenuation of trace organic contaminants during managed aquifer recharge

    Science.gov (United States)

    Regnery, J.; Strasser, A.; Hake, E.; Wing, A.; Drewes, J. E.

    2013-12-01

    For more hydrophobic trace organic contaminants present in surface water or reclaimed water applied for managed aquifer recharge (MAR), sorption onto organic matter can play a major role in attenuation in subsurface systems as the retardation allows more time for biotransformation. In case of low organic matter, other sorptive processes such as interactions with mineral surfaces gain importance. Especially for positively charged molecules, sorption onto clay materials by cation exchange will play a significant role. However, if the cation exchange capacity is limited or sorption of trace organic contaminants to clay materials is reversible due to changes in geochemical conditions (i.e., pH, ion strength), this might not provide a sustainable removal pathway. The objective of this study is to investigate how sorption to clay can enhance the removal of trace organic contaminants during MAR with the goal of evaluating the feasibility (i.e., infiltration capacity) and benefit (i.e., retardation of recalcitrant compounds) of introducing clay materials as reactive barriers in MAR systems. Laboratory-scale soil column experiments and batch sorption experiments using well characterized soil mixtures with different clay percentages under abiotic conditions and spiked at environmentally relevant concentration levels were conducted to derive soil water distribution coefficients for a suite of 15 trace organic chemicals (i.e., pharmaceutical residues, personal care products, household chemicals) and to quantify their sorption/desorption potential. All clay materials used in this study were characterized by X-ray diffraction to obtain information regarding their sorption processes. Furthermore, results were compared with geochemical field data from a full-scale MAR site in Colorado where significant amounts of clay in the subsurface were present. Preliminary results indicated that certain clay materials bear a great potential to retain moderately hydrophobic compounds such as

  1. Quantifying uncertainty from material inhomogeneity.

    Energy Technology Data Exchange (ETDEWEB)

    Battaile, Corbett Chandler; Emery, John M.; Brewer, Luke N.; Boyce, Brad Lee

    2009-09-01

    Most engineering materials are inherently inhomogeneous in their processing, internal structure, properties, and performance. Their properties are therefore statistical rather than deterministic. These inhomogeneities manifest across multiple length and time scales, leading to variabilities, i.e. statistical distributions, that are necessary to accurately describe each stage in the process-structure-properties hierarchy, and are ultimately the primary source of uncertainty in performance of the material and component. When localized events are responsible for component failure, or when component dimensions are on the order of microstructural features, this uncertainty is particularly important. For ultra-high reliability applications, the uncertainty is compounded by a lack of data describing the extremely rare events. Hands-on testing alone cannot supply sufficient data for this purpose. To date, there is no robust or coherent method to quantify this uncertainty so that it can be used in a predictive manner at the component length scale. The research presented in this report begins to address this lack of capability through a systematic study of the effects of microstructure on the strain concentration at a hole. To achieve the strain concentration, small circular holes (approximately 100 {micro}m in diameter) were machined into brass tensile specimens using a femto-second laser. The brass was annealed at 450 C, 600 C, and 800 C to produce three hole-to-grain size ratios of approximately 7, 1, and 1/7. Electron backscatter diffraction experiments were used to guide the construction of digital microstructures for finite element simulations of uniaxial tension. Digital image correlation experiments were used to qualitatively validate the numerical simulations. The simulations were performed iteratively to generate statistics describing the distribution of plastic strain at the hole in varying microstructural environments. In both the experiments and simulations, the

  2. Ultrasonic Atomization Amount for Different Frequencies

    Science.gov (United States)

    Yasuda, Keiji; Honma, Hiroyuki; Xu, Zheng; Asakura, Yoshiyuki; Koda, Shinobu

    2011-07-01

    The mass flow rate of ultrasonic atomization was estimated by measuring the vaporization amount from a bulk liquid with a fountain. The effects of ultrasonic frequency and intensity on the atomization characteristics were investigated when the directivities of the acoustic field from a transducer were almost the same. The sample was distillated water and the ultrasonic frequencies were 0.5, 1.0, and 2.4 MHz. The mass flow rate of ultrasonic atomization increased with increasing ultrasonic intensity and decreasing ultrasonic frequency. The fountain was formed at the liquid surface where the effective value of acoustic pressure was above atmospheric pressure. The fountain height was strongly governed by the acoustic pressure at the liquid surface of the transducer center. At the same ultrasonic intensity, the dependence of ultrasonic frequency on the number of atomized droplets was small. At the same apparent surface area of the fountain, the number of atomized droplets became larger as the ultrasonic frequency increased.

  3. BASELINE LEVELS OF TRACE METALS IN BLOOD OF CAPTIVE ASIAN ELEPHANTS (ELEPHAS MAXIMUS)

    Science.gov (United States)

    Wiedner, Ellen B.; Takeuchi, Noel Y.; Isaza, Ramiro; Barber, David

    2013-01-01

    Whole blood from 33 healthy captive Asian elephants (Elephas maximus) was analyzed for 12 trace elements: aluminum, chromium, manganese, cobalt, nickel, copper, zinc, arsenic, selenium, cadmium, mercury, and lead for the purpose of estimating preliminary baseline population parameters for these minerals. Metals were quantified by inductively coupled plasma mass spectroscopy. Baseline ranges for all animals and for all trace elements were comparable to normal concentrations reported in other species. This is the first report of normal trace element levels in the blood of captive elephants. PMID:22946424

  4. Consistency of trace norm minimization

    CERN Document Server

    Bach, Francis

    2007-01-01

    Regularization by the sum of singular values, also referred to as the trace norm, is a popular technique for estimating low rank rectangular matrices. In this paper, we extend some of the consistency results of the Lasso to provide necessary and sufficient conditions for rank consistency of trace norm minimization with the square loss. We also provide an adaptive version that is rank consistent even when the necessary condition for the non adaptive version is not fulfilled.

  5. THE SEGUE K GIANT SURVEY. III. QUANTIFYING GALACTIC HALO SUBSTRUCTURE

    Energy Technology Data Exchange (ETDEWEB)

    Janesh, William; Morrison, Heather L.; Ma, Zhibo; Harding, Paul [Department of Astronomy, Case Western Reserve University, Cleveland, OH 44106 (United States); Rockosi, Constance [UCO/Lick Observatory, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States); Starkenburg, Else [Department of Physics and Astronomy, University of Victoria, P.O. Box 1700, STN CSC, Victoria BC V8W 3P6 (Canada); Xue, Xiang Xiang; Rix, Hans-Walter [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Beers, Timothy C. [Department of Physics and JINA Center for the Evolution of the Elements, University of Notre Dame, Notre Dame, IN 46556 (United States); Johnson, Jennifer [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Lee, Young Sun [Department of Astronomy and Space Science, Chungnam National University, Daejeon 34134 (Korea, Republic of); Schneider, Donald P. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States)

    2016-01-10

    We statistically quantify the amount of substructure in the Milky Way stellar halo using a sample of 4568 halo K giant stars at Galactocentric distances ranging over 5–125 kpc. These stars have been selected photometrically and confirmed spectroscopically as K giants from the Sloan Digital Sky Survey’s Sloan Extension for Galactic Understanding and Exploration project. Using a position–velocity clustering estimator (the 4distance) and a model of a smooth stellar halo, we quantify the amount of substructure in the halo, divided by distance and metallicity. Overall, we find that the halo as a whole is highly structured. We also confirm earlier work using blue horizontal branch (BHB) stars which showed that there is an increasing amount of substructure with increasing Galactocentric radius, and additionally find that the amount of substructure in the halo increases with increasing metallicity. Comparing to resampled BHB stars, we find that K giants and BHBs have similar amounts of substructure over equivalent ranges of Galactocentric radius. Using a friends-of-friends algorithm to identify members of individual groups, we find that a large fraction (∼33%) of grouped stars are associated with Sgr, and identify stars belonging to other halo star streams: the Orphan Stream, the Cetus Polar Stream, and others, including previously unknown substructures. A large fraction of sample K giants (more than 50%) are not grouped into any substructure. We find also that the Sgr stream strongly dominates groups in the outer halo for all except the most metal-poor stars, and suggest that this is the source of the increase of substructure with Galactocentric radius and metallicity.

  6. Wiki surveys: Open and quantifiable social data collection

    CERN Document Server

    Salganik, Matthew J

    2012-01-01

    Research about attitudes and opinions is central to social science and relies on two common methodological approaches: surveys and interviews. While surveys enable the quantification of large amounts of information quickly and at a reasonable cost, they are routinely criticized for being "top-down" and rigid. In contrast, interviews allow unanticipated information to "bubble up" directly from respondents, but are slow, expensive, and difficult to quantify. Advances in computing technology now enable a hybrid approach that combines the quantifiability of a survey and the openness of an interview; we call this new class of data collection tools wiki surveys. Drawing on principles underlying successful information aggregation projects, such as Wikipedia, we propose three general criteria that wiki surveys should satisfy: they should be greedy, collaborative, and adaptive. We then present results from www.allourideas.org, a free and open-source website we created that enables groups all over the world to deploy w...

  7. Trace detection of specific viable bacteria using tetracysteine-tagged bacteriophages.

    Science.gov (United States)

    Wu, Lina; Luan, Tian; Yang, Xiaoting; Wang, Shuo; Zheng, Yan; Huang, Tianxun; Zhu, Shaobin; Yan, Xiaomei

    2014-01-01

    Advanced methods are urgently needed to determine the identity and viability of trace amounts of pathogenic bacteria in a short time. Existing approaches either fall short in the accurate assessment of microbial viability or lack specificity in bacterial identification. Bacteriophages (or phages for short) are viruses that exclusively infect bacterial host cells with high specificity. As phages infect and replicate only in living bacterial hosts, here we exploit the strategy of using tetracysteine (TC)-tagged phage in combination with biarsenical dye to the discriminative detection of viable target bacteria from dead target cells and other viable but nontarget bacterial cells. Using recombinant M13KE-TC phage and Escherichia coli ER2738 as a model system, distinct differentiation between individual viable target cells from dead target cells was demonstrated by flow cytometry and fluorescence microscopy. As few as 1% viable E. coli ER2738 can be accurately quantified in a mix with dead E. coli ER2738 by flow cytometry. With fluorescence microscopic measurement, specific detection of as rare as 1 cfu/mL original viable target bacteria was achieved in the presence of a large excess of dead target cells and other viable but nontarget bacterial cells in 40 mL artificially contaminated drinking water sample in less than 3 h. This TC-phage-FlAsH approach is sensitive, specific, rapid, and simple, and thus shows great potential in water safety monitoring, health surveillance, and clinical diagnosis of which trace detection and identification of viable bacterial pathogens is highly demanded.

  8. Trace Attack against Biometric Mobile Applications

    Directory of Open Access Journals (Sweden)

    Sanaa Ghouzali

    2016-01-01

    Full Text Available With the exponential increase in the dependence on mobile devices in everyday life, there is a growing concern related to privacy and security issues in the Gulf countries; therefore, it is imperative that security threats should be analyzed in detail. Mobile devices store enormous amounts of personal and financial information, unfortunately without any security. In order to secure mobile devices against different threats, biometrics has been applied and shown to be effective. However, biometric mobile applications are also vulnerable to several types of attacks that can decrease their security. Biometric information itself is considered sensitive data; for example, fingerprints can leave traces in touched objects and facial images can be captured everywhere or accessed by the attacker if the facial image is stored in the mobile device (lost or stolen. Hence, an attacker can easily forge the identity of a legitimate user and access data on a device. In this paper, the effects of a trace attack on the sensitivity of biometric mobile applications are investigated in terms of security and user privacy. Experimental results carried out on facial and fingerprint mobile authentication applications using different databases have shown that these mobile applications are vulnerable to the proposed attack, which poses a serious threat to the overall system security and user privacy.

  9. Cytocompatible cellulose hydrogels containing trace lignin.

    Science.gov (United States)

    Nakasone, Kazuki; Kobayashi, Takaomi

    2016-07-01

    Sugarcane bagasse was used as a cellulose resource to prepare transparent and flexible cellulose hydrogel films. On the purification process from bagasse to cellulose, the effect of lignin residues in the cellulose was examined for the properties and cytocompatibility of the resultant hydrogel films. The cellulose was dissolved in lithium chloride/N,N-dimethylacetamide solution and converted to hydrogel films by phase inversion. In the purification process, sodium hydroxide (NaOH) treatment time was changed from 1 to 12h. This resulted in cellulose hydrogel films having small amounts of lignin from 1.62 to 0.68%. The remaining lignin greatly affected hydrogel properties. Water content of the hydrogel films was increased from 1153 to 1525% with a decrease of lignin content. Moreover, lower lignin content caused weakening of tensile strength from 0.80 to 0.43N/mm(2) and elongation from 45.2 to 26.5%. Also, similar tendency was observed in viscoelastic behavior of the cellulose hydrogel films. Evidence was shown that the lignin residue was effective for the high strength of the hydrogel films. In addition, scanning probe microscopy in the morphological observation was suggested that the trace lignin in the cellulose hydrogel affected the cellulose fiber aggregation in the hydrogel network. The trace of lignin in the hydrogels also influenced fibroblast cell culture on the hydrogel films. The hydrogel film containing 1.68% lignin showed better fibroblast compatibility as compared to cell culture polystyrene dish used as reference.

  10. Electrostatic sampling of trace DNA from clothing.

    Science.gov (United States)

    Zieger, Martin; Defaux, Priscille Merciani; Utz, Silvia

    2016-05-01

    During acts of physical aggression, offenders frequently come into contact with clothes of the victim, thereby leaving traces of DNA-bearing biological material on the garments. Since tape-lifting and swabbing, the currently established methods for non-destructive trace DNA sampling from clothing, both have their shortcomings in collection efficiency and handling, we thought about a new collection method for these challenging samples. Testing two readily available electrostatic devices for their potential to sample biological material from garments made of different fabrics, we found one of them, the electrostatic dust print lifter (DPL), to perform comparable to well-established sampling with wet cotton swabs. In simulated aggression scenarios, we had the same success rate for the establishment of single aggressor profiles, suitable for database submission, with both the DPL and wet swabbing. However, we lost a substantial amount of information with electrostatic sampling, since almost no mixed aggressor-victim profiles suitable for database entry could be established, compared to conventional swabbing. This study serves as a proof of principle for electrostatic DNA sampling from items of clothing. The technique still requires optimization before it might be used in real casework. But we are confident that in the future it could be an efficient and convenient contribution to the toolbox of forensic practitioners.

  11. Optimum Tolerance Design Using Component-Amount and Mixture-Amount Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Piepel, Gregory F.; Ozler, Cenk; Sehirlioglu, Ali Kemal

    2013-08-01

    One type of tolerance design problem involves optimizing component and assembly tolerances to minimize the total cost (sum of manufacturing cost and quality loss). Previous literature recommended using traditional response surface (RS) designs and models to solve this type of tolerance design problem. In this article, component-amount (CA) and mixture-amount (MA) approaches are proposed as more appropriate for solving this type of tolerance design problem. The advantages of the CA and MA approaches over the RS approach are discussed. Reasons for choosing between the CA and MA approaches are also discussed. The CA and MA approaches (experimental design, response modeling, and optimization) are illustrated using real examples.

  12. 5 CFR 1655.6 - Amount of loan.

    Science.gov (United States)

    2010-01-01

    ... Administrative Personnel FEDERAL RETIREMENT THRIFT INVESTMENT BOARD LOAN PROGRAM § 1655.6 Amount of loan. (a) Minimum amount. The initial principal amount of any loan may not be less than $1,000. (b) Maximum amount. The principal amount of a new loan must be less than or equal to the smallest of the following: (1...

  13. TraceContract: A Scala DSL for Trace Analysis

    Science.gov (United States)

    Barringer, Howard; Havelund, Klaus

    2011-01-01

    In this paper we describe TRACECONTRACT, an API for trace analysis, implemented in the SCALA programming language. We argue that for certain forms of trace analysis the best weapon is a high level programming language augmented with constructs for temporal reasoning. A trace is a sequence of events, which may for example be generated by a running program, instrumented appropriately to generate events. The API supports writing properties in a notation that combines an advanced form of data parameterized state machines with temporal logic. The implementation utilizes SCALA's support for defining internal Domain Specific Languages (DSLs). Furthermore SCALA's combination of object oriented and functional programming features, including partial functions and pattern matching, makes it an ideal host language for such an API.

  14. Trace Detection of Pentaerythritol Tetranitrate Using Electrochemical Gas Sensors

    OpenAIRE

    2014-01-01

    Selective and sensitive detection of trace amounts of pentaerythritol tetranitrate (PETN) is demonstrated. The screening system is based on a sampling/concentrator front end and electrochemical potentiometric gas sensor as the detector. A single sensor is operated in the dominant hydrocarbon (HC) and nitrogen oxides (NOx) mode by varying the sensor operating condition. The potentiometric sensor with integrated heaters was used to capture the signature of PETN. Quantitative measurements based ...

  15. Accidental surface contamination - The effect on trace element analysis

    Energy Technology Data Exchange (ETDEWEB)

    Franklyn, C.B. E-mail: franklyn@aec.co.za; Ueckermann, H.; Merkle, R.K.W

    2001-07-01

    We discuss the accidental contamination of samples during a micro-PIXE study of Rh, Pd and Pt partition coefficients in the Fe-S and Ni-S systems. Trace amounts of Ni and Cu, mounted separately in epoxy as markers, were found to be present in various phases in the sections, sometimes selectively in specific mineral phases. This contamination is believed to result from polishing during preparation. Further surface contamination from conductive Ag paste was also observed.

  16. Hydrogen sulphide in human nasal air quantified using thermal desorption and selected ion flow tube mass spectrometry.

    Science.gov (United States)

    Wondimu, Taddese; Wang, Rui; Ross, Brian

    2014-09-01

    The discovery that hydrogen sulphide (H2S) acts as a gasotransmitter when present at very low concentrations (sub-parts per billion (ppbv)) has resulted in the need to quickly quantify trace amounts of the gas in complex biological samples. Selected ion flow tube mass spectrometry (SIFT-MS) is capable of real-time quantification of H2S but many SIFT-MS instruments lack sufficient sensitivity for this application. In this study we investigate the utility of combining thermal desorption with SIFT-MS for quantifying H2S in the 0.1-1 ppbv concentration range. Human orally or nasally derived breath, and background ambient air, were collected in sampling bags and dried by passing through CaCl2 and H2S pre-concentrated using a sorbent trap optimised for the capture of this gas. The absorbed H2S was then thermally desorbed and quantified by SIFT-MS. H2S concentrations in ambient air, nasal breath and oral breath collected from 10 healthy volunteers were 0.12  ±  0.02 (mean ± SD), 0.40  ±  0.11 and 3.1  ±  2.5 ppbv respectively, and in the oral cavity H2S, quantified by SIFT-MS without pre-concentration, was present at 13.5  ±  8.6 ppbv. The oral cavity H2S correlates well with oral breath H2S but not with nasal breath H2S, suggesting that oral breath H2S derives mainly from the oral cavity but nasal breath is likely pulmonary in origin. The successful quantification of such low concentrations of H2S in nasal air using a rapid analytical procedure paves the way for the straightforward analysis of H2S in breath and may assist in elucidating the role that H2S plays in biological systems.

  17. Trace determination of zinc by substoichiometric isotope dilution analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sandhya, D.; Priya, S.; Subramanian, M.O.S. [Indian Institute of Technology, Madras (India)

    1996-09-01

    A radiometric method based on substoichiometric isotope dilution analysis using 1,10-phenanthroline and a substoichiometric amount of eosin was developed for determining trace amounts of zinc. Evaluation of various metal ion interferences shows that as little as 0.2 {mu}g Zn could be determined in an aqueous-phase volume of 60 mL. The method has been successfully applied to the determination of Zn in city waste incineration ash, cadmium metal, Fourts-B tablets, Boro-plus ointment, and magnesium alloy samples. 12 refs., 3 figs., 3 tabs.

  18. Trace elements: implications for nursing.

    Science.gov (United States)

    Hayter, J

    1980-01-01

    Although most were unknown a few years ago, present evidence indicates that at least 25 trace elements have some pertinence to health. Unlike vitamins, they cannot be synthesized. Some trace elements are now considered important only because of their harmful effects but traces of them may be essential. Zinc is especially important during puberty, pregnancy and menopause and is related to protein metabolism. Both fluoride and cadmium accumulate in the body year after year. Cadmium is positively correlated with several chronic diseases, especially hypertension. It is obtained from smoking and drinking soft water. Silicon, generally associated with silicosis, may be necessary for healthy bone and connective tissue. Chromium, believed to be the glucose tolerance factor, is obtained from brewer's yeast, spices, and whole wheat products. Copper deficiency may be implicated in a wide range of cardiovascular and blood related disorders. Either marginal deficiencies or slight excesses of most trace elements are harmful. Nurses should instruct patients to avoid highly refined foods, fad diets, or synthetic and fabricated foods. A well balanced and varied diet is the best safeguard against trace element excesses or deficiencies.

  19. Trace elements in two Oxisols after annual application of sewage sludge for thirteen years

    Directory of Open Access Journals (Sweden)

    Maurício Gomes de Andrade

    2014-02-01

    Full Text Available This experiment aim was to evaluate the contamination of the trace elements (TE arsenic, barium, cadmium, chromium, copper, mercury, molybdenum, nickel, lead, selenium, and zinc considered in the CONAMA resolution 375 after 13 years long using sewage sludge (SS as fertilizer in two soils: an Eutroferric Clayed Red Latosol (Rhodic Eutrudox – RE and a Dystrophic Red Latosol (Typic Haplorthox – TH. Experiment in the field under maize cultivation had four treatments (0, 5, 10, and 20 t of SS ha-1, dry weight, five replications and an experimental design in randomized blocks. The agrochemicals (dolomitic limestone, single superphosphate, and potassium chloride, SS, soils, and the certified reference materials were digested according to the USEPA 3051A method and the chemical elements were quantified by ICP OES. The TE contents found in the agrochemicals used should not cause immediate environmental impact. The higher TE values were found in the RE and they did not reach the agricultural (more stringent Investigation Level (IL yet, according to 420 CONAMA resolution. Persisting the actual SS fertilization amount applied in the soil and the TE concentration in the SS is foreseen that Ba, Cd, Cr, Cu, Ni, and Zn will be the first elements to reach the IL in the RE.

  20. 78 FR 59702 - Medicare Program; Medicare Appeals: Adjustment to the Amount in Controversy Threshold Amounts for...

    Science.gov (United States)

    2013-09-27

    ... & Medicaid Services (CMS), HHS. ACTION: Notice. SUMMARY: This notice announces the annual adjustment in the... notice is effective on January 1, 2014. FOR FURTHER INFORMATION CONTACT: Liz Hosna ( Katherine.Hosna@cms... Improvement and Protection Act of 2000 (BIPA), established the amount in controversy (AIC) threshold...

  1. New Approaches to Quantifying Transport Model Error in Atmospheric CO2 Simulations

    Science.gov (United States)

    Ott, L.; Pawson, S.; Zhu, Z.; Nielsen, J. E.; Collatz, G. J.; Gregg, W. W.

    2012-01-01

    In recent years, much progress has been made in observing CO2 distributions from space. However, the use of these observations to infer source/sink distributions in inversion studies continues to be complicated by difficulty in quantifying atmospheric transport model errors. We will present results from several different experiments designed to quantify different aspects of transport error using the Goddard Earth Observing System, Version 5 (GEOS-5) Atmospheric General Circulation Model (AGCM). In the first set of experiments, an ensemble of simulations is constructed using perturbations to parameters in the model s moist physics and turbulence parameterizations that control sub-grid scale transport of trace gases. Analysis of the ensemble spread and scales of temporal and spatial variability among the simulations allows insight into how parameterized, small-scale transport processes influence simulated CO2 distributions. In the second set of experiments, atmospheric tracers representing model error are constructed using observation minus analysis statistics from NASA's Modern-Era Retrospective Analysis for Research and Applications (MERRA). The goal of these simulations is to understand how errors in large scale dynamics are distributed, and how they propagate in space and time, affecting trace gas distributions. These simulations will also be compared to results from NASA's Carbon Monitoring System Flux Pilot Project that quantified the impact of uncertainty in satellite constrained CO2 flux estimates on atmospheric mixing ratios to assess the major factors governing uncertainty in global and regional trace gas distributions.

  2. Quantifying synergistic information remains an unsolved problem

    CERN Document Server

    Griffith, Virgil

    2011-01-01

    We review the prior literature of information theoretical measures of synergy or synergistic information. We draw the hereto unnamed conceptual distinction between synergistic and holistic information and analyze six prior measures based on whether they aim to quantify synergy or holism. We apply all measures against a suite of examples to demonstrate no existing measure correctly quantifies synergy under all circumstances.

  3. Digital Traces of Information Systems

    DEFF Research Database (Denmark)

    Hedman, Jonas; Srinivasan, Nikhil; Lindgren, Rikard

    2013-01-01

    -dimensional framework of data sources (subjective/objective and digitalized/non-digitalized) for analyzing a six-year literature survey comprised of five leading IS journals. The analysis positions current data sources employed within the framework, and sheds light on the under utilization of digitalized data sources......In this paper, we point to the potential and implications of digital traces as novel data source in the study of contemporary activities and behaviors. We do this to raise awareness of IS researchers of such traces in increasingly complex sociomaterial practices. We develop a two....... This disconcerting result suggests that IS researchers must pay more attention to the changing landscape of data sources. To motivate and guide fellow colleagues to establish the credibility and reliability of digital traces, we develop a future research agenda that covers both opportunities in theory generation...

  4. Basecalling with LifeTrace.

    Science.gov (United States)

    Walther, D; Bartha, G; Morris, M

    2001-05-01

    A pivotal step in electrophoresis sequencing is the conversion of the raw, continuous chromatogram data into the actual sequence of discrete nucleotides, a process referred to as basecalling. We describe a novel algorithm for basecalling implemented in the program LifeTrace. Like Phred, currently the most widely used basecalling software program, LifeTrace takes processed trace data as input. It was designed to be tolerant to variable peak spacing by means of an improved peak-detection algorithm that emphasizes local chromatogram information over global properties. LifeTrace is shown to generate high-quality basecalls and reliable quality scores. It proved particularly effective when applied to MegaBACE capillary sequencing machines. In a benchmark test of 8372 dye-primer MegaBACE chromatograms, LifeTrace generated 17% fewer substitution errors, 16% fewer insertion/deletion errors, and 2.4% more aligned bases to the finished sequence than did Phred. For two sets totaling 6624 dye-terminator chromatograms, the performance improvement was 15% fewer substitution errors, 10% fewer insertion/deletion errors, and 2.1% more aligned bases. The processing time required by LifeTrace is comparable to that of Phred. The predicted quality scores were in line with observed quality scores, permitting direct use for quality clipping and in silico single nucleotide polymorphism (SNP) detection. Furthermore, we introduce a new type of quality score associated with every basecall: the gap-quality. It estimates the probability of a deletion error between the current and the following basecall. This additional quality score improves detection of single basepair deletions when used for locating potential basecalling errors during the alignment. We also describe a new protocol for benchmarking that we believe better discerns basecaller performance differences than methods previously published.

  5. Manual tracing versus smartphone application (app) tracing: a comparative study.

    Science.gov (United States)

    Sayar, Gülşilay; Kilinc, Delal Dara

    2017-11-01

    This study aimed to compare the results of conventional manual cephalometric tracing with those acquired with smartphone application cephalometric tracing. The cephalometric radiographs of 55 patients (25 females and 30 males) were traced via the manual and app methods and were subsequently examined with Steiner's analysis. Five skeletal measurements, five dental measurements and two soft tissue measurements were managed based on 21 landmarks. The durations of the performances of the two methods were also compared. SNA (Sella, Nasion, A point angle) and SNB (Sella, Nasion, B point angle) values for the manual method were statistically lower (p app method. The ANB value for the manual method was statistically lower than that of app method. L1-NB (°) and upper lip protrusion values for the manual method were statistically higher than those for the app method. Go-GN/SN, U1-NA (°) and U1-NA (mm) values for manual method were statistically lower than those for the app method. No differences between the two methods were found in the L1-NB (mm), occlusal plane to SN, interincisal angle or lower lip protrusion values. Although statistically significant differences were found between the two methods, the cephalometric tracing proceeded faster with the app method than with the manual method.

  6. Contribution of trace metals in structuring in situ macroinvertebrate community composition along a salinity gradient

    NARCIS (Netherlands)

    Peeters, E.T.H.M.; Gardeniers, J.J.P.; Koelmans, A.A.

    2000-01-01

    Macroinvertebrates were studied along a salinity gradient in the North Sea Canal, The Netherlands, to quantify the effect of trace metals (cadmium, copper, lead, zinc) on community composition. In addition, two methods for assessing metal bioavailability (normalizing metal concentrations on organic

  7. Modeling fluid- and trace element-fluxes in subducted slabs utilising two-dimensional thermodynamic and trace element models

    Science.gov (United States)

    Konrad-Schmolke, M.; Jahn, S.

    2012-12-01

    The subduction of oceanic lithosphere induces one of the major element cycles on Earth. Devolatilisation reactions in the subducted plate, the associated major and trace element transport as well as fluid-rock interaction within the slab and the mantle wedge control the flux of matter from the down-going plate into the upper plate and the atmosphere. Prediction and quantification of these fluxes is therefore a fundamental task in geosciences. The amount and composition of liberated fluids in a subducted slab is controlled by thermodynamic constraints, the fluid-rock element distribution as well as reaction kinetics in the affected rocks. Consequently, prediction of the element transfer within the slab and into the overlying rocks must consider these processes and their complex interactions. In this contribution we focus on the thermodynamic constraints on devolatilisation reactions in slab-crust and -mantle, the associated fluid migration and the chemical aspect of fluid-rock interaction within a hydrated subducted plate. Based on numerically modeled isotherm patterns of contrasting subduction settings we calculate phase relations in different layers of the subducted slabs. We use incremental Gibbs energy minimisation models and consider upward migration of liberated fluids during subduction. Moreover, modeled phase relations, fluid amounts and trace element partition coefficients, are used to calculate mass balanced distribution of fluid-mobile trace elements among the stable phases within the slab. Trace element transport occurs within the migrating fluid phase that equilibrates with the wall rock during ascent. This process controls element depletion and/or enrichment of fluid and wall rock and enables detailed prediction of the trace element transfer along the slab mantle interface. Our results show that fluid fluxes at the slab surface are clearly bimodal: at fore-arc depths water is continuously released predominantly from the MORB layer whereas at sub- and

  8. Ray tracing study for non-imaging daylight collectors

    Energy Technology Data Exchange (ETDEWEB)

    Wittkopf, Stephen [Solar Energy Research Institute of Singapore (SERIS), National University of Singapore (NUS), 7 Engineering Drive 1, Block E3A, 06-01, Singapore 117574 (Singapore); Solar Energy and Building Physics Laboratory (LESO), Swiss Federal Institute of Technology Lausanne (EPFL) (Switzerland); Oliver Grobe, Lars; Geisler-Moroder, David [Solar Energy Research Institute of Singapore (SERIS), National University of Singapore (NUS), 7 Engineering Drive 1, Block E3A, 06-01, Singapore 117574 (Singapore); Compagnon, Raphael [College of Engineering and Architecture of Fribourg (EIA-FR), University of Applied Sciences of Western Switzerland (HES-SO) (Switzerland); Kaempf, Jerome; Linhart, Friedrich; Scartezzini, Jean-Louis [Solar Energy and Building Physics Laboratory (LESO), Swiss Federal Institute of Technology Lausanne (EPFL) (Switzerland)

    2010-06-15

    This paper presents a novel method to study how well non-imaging daylight collectors pipe diffuse daylight into long horizontal funnels for illuminating deep buildings. Forward ray tracing is used to derive luminous intensity distributions curves (LIDC) of such collectors centered in an arc-shaped light source representing daylight. New photometric characteristics such as 2D flux, angular spread and horizontal offset are introduced as a function of such LIDC. They are applied for quantifying and thus comparing different collector contours. (author)

  9. Use of cloud-point preconcentration for spectrophotometric determination of trace amounts of antimony in biological and environmental samples.

    Science.gov (United States)

    El-Sharjawy, Abdel-Azeem M; Amin, Alaa S

    2016-01-01

    This work presents a cloud-point extraction process using the micelle-mediated extraction method for simultaneous preconcentration and determination of Sb(III) and Sb(V) species in biological and environmental samples as a prior preconcentration step to their spectrophotometric determination. The analytical system is based on the selective reaction between Sb(III) and 3-dichloro-6-(3-carboxy-2-hydroxy-1-naphthylazo)quinoxaline (DCHNAQ) in the presence of cetyltrimethylammonium bromide (CTAB) and potassium iodide at pH 4.5. Total Sb concentration was determined after reduction of Sb(V) to Sb(III) in the presence of potassium iodide and ascorbic acid. The optimal reaction conditions and extraction were studied, and the analytical characteristics of the method (e.g., limits of detection and quantification, linear range, preconcentration, improvement factors) were obtained. Linearity for Sb(III) was obeyed in the range of 0.2-20 ng ml(-1). The detection and quantification limits for the determination of Sb(III) were 0.055 and 0.185 ng ml(-1), respectively. The method has a lower detection limit and wider linear range, inexpensive instrument, and low cost, and is more sensitive compared with most other methods. The interference effect of some anions and cations was also studied. The method was applied to the determination of Sb(III) in the presence of Sb(V) and total antimony in blood plasma, urine, biological, and water samples.

  10. Spectrophotometric determination of trace amounts of uranium(VI) in water samples after mixed micelle-mediated extraction.

    Science.gov (United States)

    Madrakian, Tayyebeh; Afkhami, Abbas; Mousavi, Afrouz

    2007-02-15

    A cloud point extraction process using mixed micelle of the cationic surfactant CTAB and non-ionic surfactant TritonX-114 to extract uranium(VI) from aqueous solutions was investigated. The method is based on the color reaction of uranium with pyrocatechol violet in the presence of potassium iodide in hexamethylenetetramine buffer media and mixed micelle-mediated extraction of complex. The optimal extraction and reaction conditions (e.g. surfactant concentration, reagent concentration, effect of time) were studied and the analytical characteristics of the method (e.g. limit of detection, linear range, preconcentration, and improvement factors) were obtained. Linearity was obeyed in the range of 0.20-10.00ng mL(-1) of uranium(VI) ion and the detection limit of the method is 0.06ng mL(-1). The interference effect of some anions and cations was also tested. The method was applied to the determination of uranium(VI) in tap water, waste-water and well water samples.

  11. Cloud-point preconcentration and spectrophotometric determination of trace amounts of molybdenum(VI) in steels and water samples.

    Science.gov (United States)

    Madrakian, Tayyebeh; Ghazizadeh, Fariba

    2008-05-01

    A cloud-point extraction process using micelle of the cationic surfactant CTAB to extract Mo(VI) from aqueous solutions was investigated. The method is based on the color reaction of molybdenum with bromopyrogallol red in the presence of potassium iodide at pH 1.0 glycine/HCl buffer media and micelle-mediated extraction of complex. The optimal extraction and reaction conditions (e.g., surfactant concentration, reagent concentration and effect of time) were studied and the analytical characteristics of the method (e.g., limit of detection, linear range, preconcentration and improvement factors) were obtained. Linearity was obeyed in the range of 0.3-320.0 ng mL(-1) of molybdenum(VI) ion and the detection limit of the method was 0.1 ng mL(-1). The relative standard deviation (R.S.D.) and relative error for five replicate measurements of 65.0 ng mL(-1) Mo(VI) were 1.1% and 1.9%, respectively. The interference effect of some anions and cations was also tested. The method was applied to the determination of molybdenum(VI) in steels and tap water and well water samples.

  12. Novel membrane potentiometric sulfate ion sensor based on zinc-phthalocyanine for the quick determination of trace amounts of sulfate.

    Science.gov (United States)

    Ganjali, Mohammad Reza; Pourjavid, Mohammad Reza; Shamsipur, Mojtaba; Poursaeri, Taherh; Rezapour, Morteza; Javanbakht, Mehran; Sharghi, Hashem

    2003-07-01

    Poly(vinyl chloride) (PVC) based membranes of zinc-phthalocyanine (ZPC) with hexadecyltrimethylammonium bromide (HTAB) as a cation excluder, and dibutyl phthalate (DBP) and benzyl acetate (BA) as plasticizing solvent mediators were prepared and investigated as a SO4(2-) selective electrode. The best performance was observed with a membrane having a composition of ZPC-PVC-HTAB-BA in a ratio of 5%:32%:3%:60%, which works well over a wide concentration range (1.0 x 10(-2) - 1.0 x 10(-6) M) with a Nemstian slope of -29.2 mV per decade of activity, between the pH values of 2.0 to 7.0. This sensor shows a very fast response time of 10 s, and can be used over a period of 2 months with good reproducibility. The proposed sensor displays excellent selectivity for SO4(2-) over a large number of common inorganic anions. The sensor has been successfully applied for the direct and indirect determination of sulfate and zinc in zinc sulfate tablets, respectively. It was also used as an indicator electrode in the potentiometric titration of sulfate ions with barium ions.

  13. Structural and DC resistivity behaviour of Li-Mn-Ni ferrites substituted with trace amount of Co{sup 2+}

    Energy Technology Data Exchange (ETDEWEB)

    Maisnam, Mamata [Department of Physics, Manipur University, Chanchipur, Imphal-795 003 (India); Phanjoubam, Sumitra [Department of Physics, Manipur University, Chanchipur, Imphal-795 003 (India); Sarma, H.N.K. [Department of Physics, Manipur University, Chanchipur, Imphal-795 003 (India); Prakash, Chandra [Electroceramics Group, Solid State Physics Laboratory, Lucknow Road, Delhi-110 054 (India)]. E-mail: c_prakash@vsnl.net; Radhapiyari Devi, L. [Electroceramics Group, Solid State Physics Laboratory, Lucknow Road, Delhi-110 054 (India); Thakur, O.P. [Electroceramics Group, Solid State Physics Laboratory, Lucknow Road, Delhi-110 054 (India)

    2005-12-15

    This paper reports the influence of Co{sup 2+} substitution on the structural parameters and DC resistivity of Li-Mn-Ni ferrites. Samples having the compositional formula Li{sub 0.45-x/2}Ni{sub 0.1}Mn{sub 0.1}Co{sub x}Fe{sub 2.35-x/2}O{sub 4}, with x ranging from 0 to 0.01 in steps of 0.002, were prepared by the conventional ceramic technique. X-ray diffraction has confirmed the single-phase spinel structure of the samples. The lattice parameter and theoretical density of the samples were determined and the latter compared with the experimental density measured by Archimedes Principle. Porosity was found to decrease with substitution. The temperature dependence of DC resistivity shows the semiconducting nature. The resistivity and activation energies increase with the increase of substitution level.

  14. Determination of trace amount of lead in industrial and municipal effluent water samples based on dispersive liquid-liquid extraction

    Energy Technology Data Exchange (ETDEWEB)

    Shirkhanloo, H. [Iranian Petroleum Industry Health Research Institute, Occupational and Environmental Health Research Center, Tehran (Iran, Islamic Republic of); Sedighi, K.; Mousavi, H. Z., E-mail: hzmousavi@semnan.ac.ir [Semnan University, College of Science, Department of Chemistry, Semnan (Iran, Islamic Republic of)

    2014-10-01

    In this study, a simple, sensitive and accurate method was developed for the determination of lead ion by combining ionic liquid dispersive liquid-liquid extraction (Il-DLL E) with flame atomic absorption spectrometry. Tetraethyl thiuram disulfide (Tetd), acetone and 1-octyl-3m ethylimidazolium hexafluorophosphate [(C{sub 8}MIM) (PF{sub 6})] were used as the chelating agent, dispersive and extraction solvent, respectively. Under the optimal conditions, the calibration graph was linear in the range of 5-190 μg L{sup -1} of lead and the detection limit was 0.8 μg L{sup -1} with a sample volume of 200 ml. The proposed method was validated by the analysis of one certified reference material and applied successfully to the determination of lead in real water samples. (Author)

  15. Spectrofluorometric determination of trace amounts of coenzyme II using norfioxacin-terbium complex as a fluorescent probe.

    Science.gov (United States)

    Wang, Yusheng; Liu, Jinkai; Jiang, Chongqiu

    2005-06-01

    When terbium ion (Tb3+)-norfloxacin (NFLX) complex is issued a fluorescent probe, in a buffer solution of pH = 7.6, NADP can remarkably enhance the fluorescence intensity of the Tb3+ -NFLX complex at lambda = 545 nm. The enhanced fluorescence intensity of Tb3+ is in proportion to the concentration of NADP. The dynamic range for the determination of NADP is 1.11 x 10(-7) - 6.16 x 10(-5) mol l(-1), with a detection limit of 4.31 x 10(-8) mol l(-1). This method is simple, practical and relatively free of interference from coexisting substances, so it can be successfully applied to determination of NADP in synthetic water samples.

  16. Determination of Trace Amounts of Lead with ETAAS After Single Drop Microextraction and Dispersive Liquid Liquid Microextraction Methods

    OpenAIRE

    Efeçınar M.; Çakır P.; Şatıroğlu N.

    2013-01-01

    Two liquid-phase microextraction procedures, single-drop microextraction (SDME) and dispersive liquid–liquid microextraction (DLLME), have been developed for the determination of lead by electrothermal atomic absorption spectrometry (ETAAS). Both methods were based on the formation of lead iodide-Rhodamine B complex which is in phosphoric acid medium. In the presence of KI, anionic lead iodide was complexed with Rhodamine B as an ion-association complex. Several factors that may be affected o...

  17. Microstructure, mechanical properties and stress corrosion cracking of Al–Zn–Mg–Zr alloy sheet with trace amount of Sc

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xing [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Pan, Qinglin, E-mail: pql1964@126.com [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Li, Bo [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Liu, Zhiming; Huang, Zhiqi [Guangdong Fenglu Aluminum Co., Ltd, Foshan 528133 (China); Yin, Zhimin [School of Materials Science and Engineering, Central South University, Changsha 410083 (China)

    2015-11-25

    Microstructural and property evolution of the Al–Zn–Mg–0.10%Sc–0.10%Zr alloy sheet during its preparation were investigated in detail by means of optical microscopy (OM), scanning electron microscope (SEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), Vickers micro-hardness test and room temperature tensile test. Stress corrosion cracking (SCC) behavior of the Al–Zn–Mg–0.10%Sc–0.10%Zr alloy under different heat treatments was studied using slow strain rate test. The results showed that serious dendritic segregation existed in as-cast condition. The suitable homogenization treatment for Al–Zn–Mg–0.10%Sc–0.10%Zr alloy was 470 °C/24 h. After homogenization treatment, dissoluble Zn and Mg enriched non-equilibrium phases dissolved into α-Al matrix completely. The suitable solid solution-aging treatment for Al–Zn–Mg–0.10%Sc–0.10%Zr alloy was solution treated at 470 °C for 60 min, followed by water quenching and then aged at 120 °C for 24 h. Under this aging temper, the grain structures were composed of sub-grains, η′ phases and nanometer-sized, spherical Al{sub 3}(Sc, Zr) particles. Grain boundary precipitates (GBPs) area fraction was found to be an important parameter to evaluate the SCC susceptibility. The improved corrosion resistance from increasing aging temperature or prolonging aging time was due to the discontinuous η precipitates along the grain boundary and the high area fraction of GBPs. The main strengthening mechanisms of Al–Zn–Mg–0.10%Sc–0.10%Zr alloy are precipitation strengthening derived from η′ precipitates, dispersion strengthening, sub-grain strengthening and grain refinement caused by coherent Al{sub 3}(Sc, Zr) particles. - Highlights: • The suitable homogenization treatment of the alloy has been identified. • Evolution of microstructure and mechanical properties is investigated. • Strengthening mechanisms of the alloy has been established. • The basic mechanism has been proposed to model SCC of Al–Zn–Mg alloys.

  18. A time-of-flight flow sensor for the volume measurement of trace amount of interstitial fluid

    Science.gov (United States)

    Yu, H.; Li, D.; Roberts, R. C.; Xu, K.; Tien, N. C.

    2012-05-01

    Transdermal extraction of interstitial fluid (ISF) offers an attractive method for noninvasive blood glucose monitoring. The existing macroscale systems are not suitable for ISF collection, mainly because of the minute volume of the transdermally extracted ISF which scatters on the skin surface. Human skin's low permeability to glucose and its varying permeability exemplify the crucial need to make precise ISF volume measurements in order to calculate blood glucose concentrations accurately. In this paper, we present a novel time-of-flight flow sensor consisting of four electrode pairs fabricated directly into the channel of a polydimethylsiloxane (PDMS) microfluidic device designed to accurately measure the volume of transdermally extracted ISF. As fluid traverses the channel, it bridges each electrode pair and changes its resistance. By measuring the time difference in resistance change between each electrode pair, a precise fluid volume can be measured. In order to verify the suitability of the sensor for biological applications, experiments were conducted using a normal saline solution which is similar to ISF. The stability of the sensor was tested using a fixed volume, and the coefficient of variation for 20 tests was determined to be 0.0041. The consistency of the sensor for varied volume measurements was shown by the high correlation coefficient (R2 = 0.9992) between the tested volume and the volume measured by a commercial micro syringe. The excellent functionality of the flow sensor can be extended toward the measurement of conductive chemical and biochemical buffers and reagents.

  19. Determination of Trace Amounts of Lead with ETAAS After Single Drop Microextraction and Dispersive Liquid Liquid Microextraction Methods

    Directory of Open Access Journals (Sweden)

    Efeçınar M.

    2013-04-01

    Full Text Available Two liquid-phase microextraction procedures, single-drop microextraction (SDME and dispersive liquid–liquid microextraction (DLLME, have been developed for the determination of lead by electrothermal atomic absorption spectrometry (ETAAS. Both methods were based on the formation of lead iodide-Rhodamine B complex which is in phosphoric acid medium. In the presence of KI, anionic lead iodide was complexed with Rhodamine B as an ion-association complex. Several factors that may be affected on the SDME and DLLME methods were optimized. In the optimum experimental conditions, the limit of detection (3s and the enhancement factor were 0.008 μgL−1 and 152 for SDME and 0.0129 μgL−1 and 89 for DLLME respectively. The relative standard deviation (RSD for eight replicate determinations of 0.25 μgL−1 Pb was 4.6% for SDME and 0.5 μgL−1 Pb was 2.9% for DLLME. The developed methods were validated by the analysis of certified reference materials, and applied successfully to the determination of lead in several water and food samples.

  20. Trace amounts of Cu²⁺ ions influence ROS production and cytotoxicity of ZnO quantum dots.

    Science.gov (United States)

    Moussa, Hatem; Merlin, Christophe; Dezanet, Clément; Balan, Lavinia; Medjahdi, Ghouti; Ben-Attia, Mossadok; Schneider, Raphaël

    2016-03-05

    3-Aminopropyltrimethoxysilane (APTMS) was used as ligand to prepare ZnO@APTMS, Cu(2+)-doped ZnO (ZnO:Cu@APTMS) and ZnO quantum dots (QDs) with chemisorbed Cu(2+) ions at their surface (ZnO@APTMS/Cu). The dots have a diameter of ca. 5 nm and their crystalline and phase purities and composition were established by X-ray diffraction, transmission electron microscopy, UV-visible and fluorescence spectroscopies and by X-ray photoelectron spectroscopy. The effect of Cu(2+) location on the ability of the QDs to generate reactive oxygen species (ROS) under light irradiation was investigated. Results obtained demonstrate that all dots are able to produce ROS (OH, O2(-), H2O2 and (1)O2) and that ZnO@APTMS/Cu QDs generate more OH and O2(-) radicals and H2O2 than ZnO@APTMS and ZnO:Cu@APTMS QDs probably via mechanisms associating photo-induced charge carriers and Fenton reactions. In cytotoxicity experiments conducted in the dark or under light exposure, ZnO@APTMS/Cu QDs appeared slightly more deleterious to Escherichia coli cells than the two other QDs, therefore pointing out the importance of the presence of Cu(2+) ions at the periphery of the nanocrystals. On the other hand, with the lack of photo-induced toxicity, it can be inferred that ROS production cannot explain the cytotoxicity associated to the QDs. Our study demonstrates that both the production of ROS from ZnO QDs and their toxicity may be enhanced by chemisorbed Cu(2+) ions, which could be useful for medical or photocatalytic applications.

  1. Laser induced-thermal lens spectrometry after cloud point extraction for the determination of trace amounts of palladium

    Science.gov (United States)

    Shokoufi, N.; Shemirani, F.; Shokoufi, M.

    2009-10-01

    Cloud point extraction (CPE) in combination with thermal lens spectrometry (TLS) has been developed for the preconcentration and determination of palladium. TLS and CPE methods have good matching conditions for the combination because TLS is a suitable method for the analysis of low volume samples obtained after CPE. Palladium was complexed with 1-(2-pyridylazo)-2-naphthol (PAN) as a complexing agent in an aqueous medium and concentrated by octylphenoxypolyethoxyethanol (Triton X-114) as a surfactant. After the phase separation at 60 °C based on the cloud point extraction of the mixture, the surfactant-rich phase was dried and the remaining phase was dissolved using 20 μL of carbon tetrachloride. The obtained solution was introduced into a quartz microcell and the analyte was determined by laser induced-thermal lens spectrometry (LI-TLS). The single-laser TLS was used as a sensitive method for the determination of palladium-PAN complex in 20 μL of the sample. Under optimum conditions, the analytical curve was linear for the concentration range of 0.3-60 ng mL -1 and the detection limit was 0.04 ng mL -1. The enhancement factor of 460 was achieved for 10 mL samples containing the analyte and relative standard deviations were lower than 5%. The developed method was successfully applied to the extraction and determination of palladium in water samples.

  2. Cloud-point preconcentration and spectrophotometric determination of trace amounts of molybdenum(VI) in steels and water samples

    Energy Technology Data Exchange (ETDEWEB)

    Madrakian, Tayyebeh [Faculty of Chemistry, Bu-Ali Sina University, Hamadan (Iran, Islamic Republic of)], E-mail: madrakian@basu.ac.ir; Ghazizadeh, Fariba [Faculty of Chemistry, Bu-Ali Sina University, Hamadan (Iran, Islamic Republic of)

    2008-05-01

    A cloud-point extraction process using micelle of the cationic surfactant CTAB to extract Mo(VI) from aqueous solutions was investigated. The method is based on the color reaction of molybdenum with bromopyrogallol red in the presence of potassium iodide at pH 1.0 glycine/HCl buffer media and micelle-mediated extraction of complex. The optimal extraction and reaction conditions (e.g., surfactant concentration, reagent concentration and effect of time) were studied and the analytical characteristics of the method (e.g., limit of detection, linear range, preconcentration and improvement factors) were obtained. Linearity was obeyed in the range of 0.3-320.0 ng mL{sup -1} of molybdenum(VI) ion and the detection limit of the method was 0.1 ng mL{sup -1}. The relative standard deviation (R.S.D.) and relative error for five replicate measurements of 65.0 ng mL{sup -1} Mo(VI) were 1.1% and 1.9%, respectively. The interference effect of some anions and cations was also tested. The method was applied to the determination of molybdenum(VI) in steels and tap water and well water samples.

  3. Cloud point extraction, preconcentration and spectrophotometric determination of trace amount of manganese(II) in water and food samples

    Science.gov (United States)

    Gouda, Ayman A.

    2014-10-01

    A new cloud point extraction (CPE) process using the nonionic surfactant Triton X-114 to extract manganese(II) from aqueous solution was investigated. The method is based on the complexation reaction of manganese(II) with 1,2,5,8-tetrahydroxyanthracene-9,10-dione (quinalizarin) in the presence of borate buffer at pH 8.5 and micelle-mediated extraction of the complex. The enriched analyte in the surfactant-rich phase was determined by spectrophotometry at 528 nm. The optimal extraction and reaction conditions (e.g. pH, reagent and surfactant concentrations, temperature and centrifugation times) were evaluated and optimized. Under the optimized experimental conditions, the analytical characteristics of the method (e.g., limit of detection (LOD), linear range, preconcentration and improvement factors) were obtained. The proposed CPE method showed linear calibration within the range 5.0-200 ng mL-1 of manganese(II) and the limit of detection of the method was 0.8 ng mL-1 with an preconcentration factor of ∼50 when 25 mL of sample solution was preconcentrated to 0.5 mL. The relative standard deviation (RSD) and relative error were found to be 1.35% and 1.42%, respectively (CMn(II) = 150 ng mL-1, n = 6) for pure standard solutions. The interference effect of some cations and anions was also studied. In the presence of foreign ions, no significant interference was observed. The method was applied to the determination of manganese(II) in water and food samples with a recovery for the spiked samples in the range of 95.87-102.5%.

  4. Trace amounts of Cu{sup 2+} ions influence ROS production and cytotoxicity of ZnO quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Moussa, Hatem [CNRS and Université de Lorraine, Laboratoire Réactions et Génie des Procédés (LRGP), CNRS UMR 7274, 1 rue Grandville, 54001 Nancy (France); Laboratoire de Biosurveillance de l' Environnement, Université de Carthage, Faculté des Sciences de Bizerte, 7021 Jarzouna, Bizerte (Tunisia); Merlin, Christophe [CNRS and Université de Lorraine, Laboratoire de Chimie Physique et Microbiologie pour l' Environnement (LCPME), CNRS UMR 7564, 15 Avenue du Charmois, 54500 Vandoeuvre-lès-Nancy (France); Dezanet, Clément [CNRS and Université de Lorraine, Laboratoire Réactions et Génie des Procédés (LRGP), CNRS UMR 7274, 1 rue Grandville, 54001 Nancy (France); Balan, Lavinia [Institut de Science des Matériaux de Mulhouse (IS2M), CNRS UMR 7361, 15 rue Jean Starcky, 68093 Mulhouse (France); Medjahdi, Ghouti [CNRS and Université de Lorraine, Institut Jean Lamour (IJL), UMR CNRS 7198, BP 70239, 54506 Vandoeuvre-lès-Nancy Cedex (France); Ben-Attia, Mossadok [Laboratoire de Biosurveillance de l' Environnement, Université de Carthage, Faculté des Sciences de Bizerte, 7021 Jarzouna, Bizerte (Tunisia); and others

    2016-03-05

    Highlights: • Chemisorbed Cu{sup 2+} ions on ZnO QDs enhance ROS production. • A mechanism combining excited electrons and holes and Fenton reactions is proposed. • ZnO@APTMS/Cu QDs were found to be the most deleterious to E. coli cells. - Abstract: 3-Aminopropyltrimethoxysilane (APTMS) was used as ligand to prepare ZnO@APTMS, Cu{sup 2+}-doped ZnO (ZnO:Cu@APTMS) and ZnO quantum dots (QDs) with chemisorbed Cu{sup 2+} ions at their surface (ZnO@APTMS/Cu). The dots have a diameter of ca. 5 nm and their crystalline and phase purities and composition were established by X-ray diffraction, transmission electron microscopy, UV-visible and fluorescence spectroscopies and by X-ray photoelectron spectroscopy. The effect of Cu{sup 2+} location on the ability of the QDs to generate reactive oxygen species (ROS) under light irradiation was investigated. Results obtained demonstrate that all dots are able to produce ROS (·OH, O{sub 2}·{sup −}, H{sub 2}O{sub 2} and {sup 1}O{sub 2}) and that ZnO@APTMS/Cu QDs generate more ·OH and O{sub 2}·{sup −} radicals and H{sub 2}O{sub 2} than ZnO@APTMS and ZnO:Cu@APTMS QDs probably via mechanisms associating photo-induced charge carriers and Fenton reactions. In cytotoxicity experiments conducted in the dark or under light exposure, ZnO@APTMS/Cu QDs appeared slightly more deleterious to Escherichia coli cells than the two other QDs, therefore pointing out the importance of the presence of Cu{sup 2+} ions at the periphery of the nanocrystals. On the other hand, with the lack of photo-induced toxicity, it can be inferred that ROS production cannot explain the cytotoxicity associated to the QDs. Our study demonstrates that both the production of ROS from ZnO QDs and their toxicity may be enhanced by chemisorbed Cu{sup 2+} ions, which could be useful for medical or photocatalytic applications.

  5. Rapid spectrophotometric determination of trace amounts of palladium in water samples after dispersive liquid-liquid microextraction.

    Science.gov (United States)

    Rahnama Kozani, Reyhaneh; Mofid-Nakhaei, Jamshid; Jamali, Mohammad Reza

    2013-08-01

    A simple, rapid, and efficient dispersive liquid-liquid microextraction method, followed by UV-Vis spectrophotometry was developed for the preconcentration and determination of Pd ions in water samples. Pd ions react with α-furildioxime (chelating agent) to form a hydrophobic complex. Various parameters were altered to study and optimize their effects on the extraction efficiency, such as pH, ligand concentration, the type and volume of extraction and dispersive solvents, extraction time, and salt concentration. Under optimized conditions, the method exhibited an enrichment factor (C org/C aq) of 25 and recovery more than 98 % within a very short extraction time. The linearity of the method ranged from 10 to 200 μg L(-1). The limit of detection was 1.1 μg L(-1). The relative standard deviation for the concentration of 100 μg L(-1) of Pd was 2.3 % (n = 10). Finally, the developed method was successfully applied to the extraction and determination of Pd in tap, river, mineral, and sea water samples.

  6. Determination of Trace Amounts of Chromium(III) in Water Samples Using Online Flow Injection Catalytic Spectrophotometry

    Science.gov (United States)

    Zhao, Z. X.; Zhang, X. S.

    2017-01-01

    A new online flow injection spectrophotometric method for the determination of trivalent chromium was developed. This method is based on the property of trivalent chromium to be a catalyst for the oxidation of Indigo Carmine (IC) with potassium periodate and to lose its color in the presence of ethylenediaminetetraacetic acid and sodium tripolyphosphate. It was shown that Tween-20 serves as an additional accelerator of the catalytic oxidation. The linear dynamic range of the determination of Cr(III) was 1-40.0 μg/L, while the limit of detection was 0.05 μg/L. The correlation coefficient r was 0.998, while the relative standard deviation for 5 μg/L of the Cr(III) solution was 3.83%. The feasibility of this method was checked by its application to trivalent chromium determination in real water samples.

  7. Determination of Trace Amounts of Nickel (Ⅱ) by Graphite Furnace Atomic Absorption Spectrometry Coupled with Cloud Point Extraction

    Institute of Scientific and Technical Information of China (English)

    SHAH Syed Mazhar; WANG Hao-nan; SU Xing-guang

    2011-01-01

    A new method based on the cloud point extraction(CPE) for separation and preconcentration of nickel(Ⅱ)and its subsequent determination by graphite furnace atomic absorption spectrometry(GFAAS) was proposed,8-hydroxyquinoline and Triton X-100 were usedl as the ligand and surfactant respectively. Nickel(Ⅱ) can form a hydrophobic complex with 8-hydroxyquinoline, the complex can be extracted into the small volume surfactant rich phase at the cloud point temperature(CPT) for GFAAS determination. The factors affecting the cloud point extraction,such as pH, ligand concentration, surfactant concentration, and the incubation time were optimized. Under the optimal conditions, a detection limit of 12 ng/L and a relative standard deviation(RSD) of 2.9% were obtained for Ni(Ⅱ) determination. The enrichment factor was found to be 25. The proposed method was successfully applied to the determination of nickel(Ⅱ) in certified reference material and different types of water samples and the recovery was in a range of 95% 103%.

  8. Simultaneous determination of ultra trace amounts of lead and cadmium in food samples by adsorptive stripping voltammetry.

    Science.gov (United States)

    Abbasi, Shahryar; Khodarahmiyan, Kobra; Abbasi, Freshteh

    2011-09-01

    A selective and sensitive method for simultaneous determination of lead and cadmium by adsorptive differential pulse cathodic stripping voltammetry is presented. The method is based on adsorptive accumulation of the complexes of Pb (II) and Cd (II) ions with 2-mercaptobenzothiazole onto hanging mercury drop electrode (HMDE), followed by the reduction of the adsorbed species by differential pulse cathodic stripping voltammetry. Optimal conditions were obtained at pH 8.0, 2-mercaptobenzothiazole concentration of 1.0×10(-4)M, the accumulation potential of -0.4V (vs. Ag/AgCl), the accumulation time of 160s, and the scan rate of 100mV/s. Under optimised conditions, linear calibration curves were established for the concentration of Pb (II) and Cd (II) in the range of 0.5-70 and 0.2-30ng/ml, respectively, with detection limit of 0.017ng/ml for Pb (II) and 0.01ng/ml for Cd (II). The procedure was successfully applied to the simultaneous determination of both ions in food samples (rice, soya and sugar). Published by Elsevier Ltd.

  9. Elimination of interferences from surface active substances in voltammetric determination of trace amounts of titanium in environmental water samples

    Directory of Open Access Journals (Sweden)

    Grabarczyk M.

    2013-04-01

    Full Text Available A cathodic stripping voltammetric method for determination of Ti(IV in water samples containing high concentrations of surfactants is described. The linear calibration plot for Ti(IV was achieved in the simultaneous presence of 5 mg L-1 anionic, 1 mg L-1 cationic and 2 mg L-1 nonionic surfactants for an accumulation time of 30 s in the range 2.5 × 10-8 to 5 × 10-7 mol L-1, the detection limit for accumulation time of 30 s was about 8.4 × 10-9 mol L-1. The developed method was successfully applied to Ti(IV determination in environmental waters, such as river water (Bystrzyca, Czerniejówka, stagnant water (Lake Zemborzyce and rain water (collected from eastern areas of Poland with satisfactory results.

  10. Determination of ultra trace amount of enrofloxacin by adsorptive cathodic stripping voltammetry using copper(II) as an intermediate.

    Science.gov (United States)

    Ensaifi, Ali A; Khayamian, T; Taei, M

    2009-05-15

    In this work, a simple and sensitive electroanalytical method was developed for the determination of enrofloxacin (ENRO) by adsorptive cathodic stripping voltammetry (ADSV) using Cu(II) as a suitable probe. The complex of copper(II) with ENRO was accumulated at the surface of a hanging mercury drop electrode at -0.10 V for 40 s. Then, the preconcentrated complex was reduced and the peak current was measured using square wave voltammetry (SWV). The optimization of experimental variables was conducted by experimental design and support vector machine (SVM) modeling. The model was used to find optimized values for the factors such as pH, Cu(II) concentration and accumulation potential. Under the optimized conditions, the peak current at -0.30 V is proportional to the concentration of ENRO over the range of 10.0-80.0 nmol L(-1) with a detection limit of 0.33 nmol L(-1). The influence of potential interfering substances on the determination of ENRO was examined. The method was successfully applied to determination of ENRO in plasma and pharmaceutical samples.

  11. The investigation of ionization conditions in the trace amounts detection of heterocyclic compounds by ion mobility spectrometry and mass spectrometry

    Science.gov (United States)

    Shaltaeva, Y. R.; Sysoev, A. A.; Poteshin, S. S.; Negru, K. I.; Grishin, S. S.; Trefilova, V. V.; Zuev, M. I.; Baberkina, E. P.

    2016-10-01

    The first part of paper is devoted to the detection of New Psychoactive Substances by ion mobility mass spectrometry study. In the second part of the paper presents a promising approach to prevent the spread of narcotic substances, consisting in the use of field-portable ion mobility spectrometers and finding the correlation between the peaks of the spectrograms of ion mobility and the chemical structure of the compound.

  12. Cloud point extraction, preconcentration and spectrophotometric determination of trace amount of manganese(II) in water and food samples.

    Science.gov (United States)

    Gouda, Ayman A

    2014-10-15

    A new cloud point extraction (CPE) process using the nonionic surfactant Triton X-114 to extract manganese(II) from aqueous solution was investigated. The method is based on the complexation reaction of manganese(II) with 1,2,5,8-tetrahydroxyanthracene-9,10-dione (quinalizarin) in the presence of borate buffer at pH 8.5 and micelle-mediated extraction of the complex. The enriched analyte in the surfactant-rich phase was determined by spectrophotometry at 528nm. The optimal extraction and reaction conditions (e.g. pH, reagent and surfactant concentrations, temperature and centrifugation times) were evaluated and optimized. Under the optimized experimental conditions, the analytical characteristics of the method (e.g., limit of detection (LOD), linear range, preconcentration and improvement factors) were obtained. The proposed CPE method showed linear calibration within the range 5.0-200ngmL(-1) of manganese(II) and the limit of detection of the method was 0.8ngmL(-1) with an preconcentration factor of ∼50 when 25mL of sample solution was preconcentrated to 0.5mL. The relative standard deviation (RSD) and relative error were found to be 1.35% and 1.42%, respectively (CMn(II)=150ngmL(-1), n=6) for pure standard solutions. The interference effect of some cations and anions was also studied. In the presence of foreign ions, no significant interference was observed. The method was applied to the determination of manganese(II) in water and food samples with a recovery for the spiked samples in the range of 95.87-102.5%.

  13. Quantifying uncertainty in proxy-based paleoclimate reconstructions

    Science.gov (United States)

    D'Andrea, William J.; Polissar, Pratigya J.

    2017-04-01

    There are now numerous geochemical tools that can provide quantitative estimates of past temperatures and hydrologic variables. These proxies for past climate are usually calibrated using empirical relationships with quantifiable uncertainty. Laboratory analysis introduces additional sources of uncertainty that must also be accounted for in order to fully propagate the uncertainty in an estimated climate variable. The aim of this presentation is to review the sources of uncertainty that can be quantified and reported when using different geochemical climate proxies for paleoclimate reconstruction. I will consider a number of widely used climate proxies, discuss the relative importance of various sources of uncertainty for each, and attempt to identify ways in which the scientific community might reduce these uncertainties. For example, compound-specific δD measurements can be used for quantitative estimation of source water δD values, a useful tracer for paleohydrologic changes. Such estimates have quantifiable levels of uncertainty that are often miscalculated, resulting in inaccurate error reporting in the scientific literature that can impact paleohydrologic interpretations. Here, I will summarize the uncertainties inherent to molecular δD measurements and the quantification of source water δD values, and discuss the assumptions involved when omitting various sources of uncertainty. The analytical uncertainty of δD measurements is often improperly estimated and secondary to the apparent fractionation between δD values of source water and molecule, normalization of data to the VSMOW scale introduces the largest amount of uncertainty.

  14. Partial Automation of Requirements Tracing

    Science.gov (United States)

    Hayes, Jane; Dekhtyar, Alex; Sundaram, Senthil; Vadlamudi, Sravanthi

    2006-01-01

    Requirements Tracing on Target (RETRO) is software for after-the-fact tracing of textual requirements to support independent verification and validation of software. RETRO applies one of three user-selectable information-retrieval techniques: (1) term frequency/inverse document frequency (TF/IDF) vector retrieval, (2) TF/IDF vector retrieval with simple thesaurus, or (3) keyword extraction. One component of RETRO is the graphical user interface (GUI) for use in initiating a requirements-tracing project (a pair of artifacts to be traced to each other, such as a requirements spec and a design spec). Once the artifacts have been specified and the IR technique chosen, another component constructs a representation of the artifact elements and stores it on disk. Next, the IR technique is used to produce a first list of candidate links (potential matches between the two artifact levels). This list, encoded in Extensible Markup Language (XML), is optionally processed by a filtering component designed to make the list somewhat smaller without sacrificing accuracy. Through the GUI, the user examines a number of links and returns decisions (yes, these are links; no, these are not links). Coded in XML, these decisions are provided to a "feedback processor" component that prepares the data for the next application of the IR technique. The feedback reduces the incidence of erroneous candidate links. Unlike related prior software, RETRO does not require the user to assign keywords, and automatically builds a document index.

  15. Tracing differential reddening with Diffuse Interstellar Bands. The globular cluster M 4 as a testbed

    CERN Document Server

    Monreal-Ibero, A; Puspitarini, L; Bonifacio, P; Monaco, L

    2015-01-01

    Diffuse interstellar bands (DIBs) are weak absorption features of interstellar origin present in the optical and infrared spectra of stars. Their use as a tool to trace the structure of the Galactic ISM is gaining relevance in the recent years. Here we present an experiment to test our ability to trace differential reddening on the plane of the sky by using the information relative to the DIB at $\\lambda$6614 extracted from the spectra of cool stars. For that we made use of archive FLAMES data of the globular cluster M4, as well as WISE and Planck images for reference. We found a global positive trend between the distribution of the strength of the DIB, as traced by its equivalent width, and the amount of Galactic reddening, as traced by Planck. This result supports the use of DIBs to trace the small scale structure of the Galactic ISM.

  16. 42 CFR 418.309 - Hospice cap amount.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 3 2010-10-01 2010-10-01 false Hospice cap amount. 418.309 Section 418.309 Public...) MEDICARE PROGRAM HOSPICE CARE Payment for Hospice Care § 418.309 Hospice cap amount. The hospice cap amount is calculated using the following procedures: (a) The cap amount is $6,500 per year and is adjusted...

  17. Enhanced Userspace and In-Kernel Trace Filtering for Production Systems

    Institute of Scientific and Technical Information of China (English)

    Suchakrapani Datt Sharma; Michel Dagenais

    2016-01-01

    Trace tools like LTTng have a very low impact on the traced software as compared with traditional debuggers. However, for long runs, in resource constrained and high throughput environments, such as embedded network switching nodes and production servers, the collective tracing impact on the target software adds up considerably. The overhead is not just in terms of execution time but also in terms of the huge amount of data to be stored, processed and analyzed offline. This paper presents a novel way of dealing with such huge trace data generation by introducing a Just-In-Time (JIT) filter based tracing system, for sieving through the flood of high frequency events, and recording only those that are relevant, when a specific condition is met. With a tiny filtering cost, the user can filter out most events and focus only on the events of interest. We show that in certain scenarios, the JIT compiled filters prove to be three times more effective than similar interpreted filters. We also show that with the increasing number of filter predicates and context variables, the benefits of JIT compilation increase with some JIT compiled filters being even three times faster than their interpreted counterparts. We further present a new architecture, using our filtering system, which can enable co-operative tracing between kernel and process tracing VMs (virtual machines) that share data efficiently. We demonstrate its use through a tracing scenario where the user can dynamically specify syscall latency through the userspace tracing VM whose effect is reflected in tracing decisions made by the kernel tracing VM. We compare the data access performance on our shared memory system and show an almost 100 times improvement over traditional data sharing for co-operative tracing.

  18. The discrimination of discrete and continuous amounts in African grey parrots (Psittacus erithacus).

    Science.gov (United States)

    Aïn, Syrina Al; Giret, Nicolas; Grand, Marion; Kreutzer, Michel; Bovet, Dalila

    2009-01-01

    A wealth of research in infants and animals demonstrates discrimination of quantities, in some cases nonverbal numerical perception, and even elementary calculation capacities. We investigated the ability of three African grey parrots (Psittacus erithacus) to select the largest amount of food between two sets, either discrete food items (experiment 1) or as volume of a food substance (experiment 2). The two amounts were presented simultaneously and were visible at the time of choice. Parrots were tested several times for all possible combinations between 1 and 5 seeds or 0.2 and 1 ml of food substance. In both conditions, subjects performed above chance for almost all combinations. Accuracy was negatively correlated with the ratio, that is performance improved with greater differences between amounts. Therefore, these results with both individual items and volume discrimination suggest that parrots use an analogue of magnitude, rather than object-file mechanisms to quantify items and substances.

  19. Trace elements and rat pouchitis.

    Science.gov (United States)

    Drzymała-Czyż, Sławomira; Banasiewicz, Tomasz; Walas, Stanisław; Kościński, Tomasz; Wenska-Chyży, Ewa; Drews, Michał; Walkowiak, Jarosław

    2012-01-01

    The procedure of restorative proctocolectomy is associated with a complete removal of the colon and slight reduction of ileum length, which together can lead to systemic shortages of trace elements. Inflammatory changes in the pouch mucosa may also have some impact. However, there is no data on trace elements in pouchitis. Therefore, in the present study we aimed to assess the effect of acute pouchitis on the status of selected trace elements in rats. Restorative proctocolectomy with the construction of intestinal J-pouch was performed in twenty-four Wistar rats. Three weeks after the surgery, pouchitis was induced. Eight untreated rats created the control group. Liver concentrations of selected micronutrients (Zn, Cu, Co, Mn, Se) were measured in both groups six weeks later, using inductively coupled plasma mass spectrometry. Liver concentrations of trace elements did not differ between the study and the control groups. However, copper, cobalt and selenium concentrations [μg/g] were statistically lower (p<0.02, p<0.05 and p<0.04, respectively) in rats with severe pouchitis (n=9) as compared with rats with mild pouchitis (n=7) [median (range): Cu--7.05 (3.02-14.57) vs 10.47 (5.16-14.97); Co--0.55 (0.37-0.96) vs 0.61 (0.52-0.86); Se--1.17 (0.69-1.54) vs 1.18 (0.29-1.91)]. In conclusion, it seems that acute pouchitis can lead to a significant deficiency of trace elements.

  20. Protocol for quantitative tracing of surface water with synthetic DNA

    Science.gov (United States)

    Foppen, J. W.; Bogaard, T. A.

    2012-04-01

    Based on experiments we carried out in 2010 with various synthetic single stranded DNA markers with a size of 80 nucleotides (ssDNA; Foppen et al., 2011), we concluded that ssDNA can be used to carry out spatially distributed multi-tracer experiments in the environment. Main advantages are in principle unlimited amount of tracers, environmental friendly and tracer recovery at very high dilution rates (detection limit is very low). However, when ssDNA was injected in headwater streams, we found that at selected downstream locations, the total mass recovery was less than 100%. The exact reason for low mass recovery was unknown. In order to start identifying the cause of the loss of mass in these surface waters, and to increase our knowledge of the behaviour of synthetic ssDNA in the environment, we examined the effect of laboratory and field protocols working with artificial DNA by performing numerous batch experiments. Then, we carried out several field tests in different headwater streams in the Netherlands and in Luxembourg. The laboratory experiments consisted of a batch of water in a vessel with in the order of 10^10 ssDNA molecules injected into the batch. The total duration of each experiment was 10 hour, and, at regular time intervals, 100 µl samples were collected in a 1.5 ml Eppendorf vial for qPCR analyses. The waters we used ranged from milliQ water to river water with an Electrical Conductivity of around 400 μS/cm. The batch experiments were performed in different vessel types: polyethylene bottles, polypropylene copolymer bottles , and glass bottles. In addition, two filter types were tested: 1 µm pore size glass fibre filters and 0.2 µm pore size cellulose acetate filters. Lastly, stream bed sediment was added to the batch experiments to quantify interaction of the DNA with sediment. For each field experiment around 10^15 ssDNA molecules were injected, and water samples were collected 100 - 600 m downstream of the point of injection. Additionally

  1. Tracing the origin of Arctic driftwood

    Science.gov (United States)

    Hellmann, Lena; Tegel, Willy; Eggertsson, Ã.`Lafur; Schweingruber, Fritz Hans; Blanchette, Robert; Kirdyanov, Alexander; GäRtner, Holger; Büntgen, Ulf

    2013-03-01

    Arctic environments, where surface temperatures increase and sea ice cover and permafrost depth decrease, are very sensitive to even slight climatic variations. Placing recent environmental change of the high-northern latitudes in a long-term context is, however, complicated by too short meteorological observations and too few proxy records. Driftwood may represent a unique cross-disciplinary archive at the interface of marine and terrestrial processes. Here, we introduce 1445 driftwood remains from coastal East Greenland and Svalbard. Macroscopy and microscopy were applied for wood anatomical classification; a multi-species subset was used for detecting fungi; and information on boreal vegetation patterns, circumpolar river systems, and ocean current dynamics was reviewed and evaluated. Four conifer (Pinus, Larix, Picea, and Abies) and three deciduous (Populus, Salix, and Betula) genera were differentiated. Species-specific identification also separated Pinus sylvestris and Pinus sibirica, which account for ~40% of all driftwood and predominantly originate from western and central Siberia. Larch and spruce from Siberia or North America represents ~26% and ~18% of all materials, respectively. Fungal colonization caused different levels of driftwood staining and/or decay. Our results demonstrate the importance of combining wood anatomical knowledge with insight on boreal forest composition for successfully tracing the origin of Arctic driftwood. To ultimately reconstruct spatiotemporal variations in ocean currents, and to better quantify postglacial uplift rates, we recommend consideration of dendrochronologically dated material from many more circumpolar sites.

  2. Catalytic spectrophotometric determination of trace selenium in microemulsion after separation and enrichment by SDG

    Institute of Scientific and Technical Information of China (English)

    LI Huizhi; ZHAI Diantang; FAN Yingju

    2006-01-01

    A new catalytic spectrophotometric method was developed for the determination of trace amount of Se(Ⅳ) in microemulsion medium. The method is based on the catalytic effect of traces of Se(Ⅳ) on the oxidation of2',4'-dichlorophenylfluorone (p-CPF) by potassium bromate with HNO3 as an activator in the presence of nonionic microemulsion medium. Under optimum conditions, the calibration graph is linear in the range of 0.4-15 μg. L-1 of Se(Ⅳ) atseparated and enriched by sulphydryl dextrane gel (SDG). The method has been applied for determination of trace selenium with satisfactory results.

  3. Gas adsorption and desorption effects on high pressure small volume cylinders and their relevance to atmospheric trace gas analysis

    Science.gov (United States)

    Satar, Ece; Nyfeler, Peter; Pascale, Céline; Niederhauser, Bernhard; Leuenberger, Markus

    2017-04-01

    Long term atmospheric monitoring of trace gases requires great attention to precision and accuracy of the measurement setups. For globally integrated and well established greenhouse gas observation networks, the World Meteorological Organization (WMO) has set recommended compatibility goals within the framework of its Global Atmosphere Watch (GAW) Programme [1]. To achieve these challenging limits, the measurement systems are regularly calibrated with standard gases of known composition. Therefore, the stability of the primary and secondary gas standards over time is an essential issue. Past studies have explained the small instabilities in high pressure standard gas cylinders through leakage, diffusion, regulator effects, gravimetric fractionation and surface processes [2, 3]. The latter include adsorption/desorption, which are functions of temperature, pressure and surface properties. For high pressure standard gas mixtures used in atmospheric trace gas analysis, there exists only a limited amount of data and few attempts to quantify the surface processes [4, 5]. Specifically, we have designed a high pressure measurement chamber to investigate trace gases and their affinity for adsorption on different surfaces over various temperature and pressure ranges. Here, we focus on measurements of CO2, CH4 and CO using a cavity ring down spectroscopy analyzer and quantify the concentration changes due to adsorption/desorption. In this study, the first results from these prototype cylinders of steel and aluminum will be presented. References [1] World Meteorological Organization (WMO), Global Atmosphere Watch.(GAW): Report No. 229, 18th WMO/IAEA Meeting on Carbon Dioxide, Other Greenhouse Gases and Related Tracers Measurement Techniques (GGMT-2015), 2016. [2] Keeling, R. F., Manning, A. C., Paplawsky, W. J., and Cox, A. C.: On the long-term stability of reference gases for atmospheric O2 /N2 and CO2 measurements, Tellus B, 59, 10.3402/tellusb.v59i1.16964, 2007. [3

  4. Nitrogen dioxide observations from the Geostationary Trace ...

    Science.gov (United States)

    The Geostationary Trace gas and Aerosol Sensor Optimization (GeoTASO) airborne instrument is a test bed for upcoming air quality satellite instruments that will measure backscattered ultraviolet, visible and near-infrared light from geostationary orbit. GeoTASO flew on the NASA Falcon aircraft in its first intensive field measurement campaign during the Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) Earth Venture Mission over Houston, Texas, in September 2013. Measurements of backscattered solar radiation between 420 and 465 nm collected on 4 days during the campaign are used to determine slant column amounts of NO2 at 250 m  ×  250 m spatial resolution with a fitting precision of 2.2 × 1015 moleculescm−2. These slant columns are converted to tropospheric NO2 vertical columns using a radiative transfer model and trace gas profiles from the Community Multiscale Air Quality (CMAQ) model. Total column NO2 from GeoTASO is well correlated with ground-based Pandora observations (r = 0.90 on the most polluted and cloud-free day of measurements and r = 0.74 overall), with GeoTASO NO2 slightly higher for the most polluted observations. Surface NO2 mixing ratios inferred from GeoTASO using the CMAQ model show good correlation with NO2 measured in situ at the surface during the campaign (r = 0.85). NO2 slant columns from GeoTASO also agree well with prelim

  5. Accelerated trace eyeblink conditioning after cortisol IV-infusion.

    Science.gov (United States)

    Kuehl, Linn K; Lass-Hennemann, Johanna; Richter, Steffen; Blumenthal, Terry D; Oitzl, Melly; Schachinger, Hartmut

    2010-11-01

    Impairing effects of cortisol on learning performance have been shown in human trace eyeblink conditioning. As the effect is observed from 30 min to hours after administration, a genomic action of cortisol is assumed. Here we report rapid cortisol effects that were observed during the first 10 min after cortisol administration in humans. Young healthy males (n=24) received the cortisol synthesis inhibitor metyrapone (1.5 g per os) to avoid interference of the endogenous pulsatile secretion of cortisol. Next, 2mg cortisol or placebo was infused intravenously, immediately before the trace conditioning task. The probability of the conditioned eyeblink responses was assessed electromyographically during the trace eyeblink conditioning task (unconditioned stimulus: corneal air puff, 10 psi, 50 ms; conditioned stimulus: binaural pure tone, 7 dB, 1000 Hz, 400 ms; empty interval between CS and US: 550 ms). Cortisol resulted in a faster increase of conditioning (p=.02), reaching a comparable level to placebo later on. This result extends the well-known effects of stress on the quality and amount of learning by showing that cortisol also affects the speed of learning. We propose that cortisol accelerates trace eyeblink conditioning via a fast, non-genomic mechanism. This fast action of cortisol is part of the adaptive strategy during the early stress response.

  6. Trace metals and cancer: The case of neuroblastoma

    Science.gov (United States)

    Gouget, B.; Sergeant, C.; Llabador, Y.; Devès, G.; Vesvres, M. H.; Simonoff, M.; Bénard, J.

    2001-07-01

    N- myc oncogene amplification is one of the most established prognostic factors in neuroblastoma (NB), a young children solid tumor. Amounts of ferritin, an iron storage protein, are abnormally increased in serum of patients with advanced stage disease. N- myc amplified NB cells can synthesize zinc metalloenzymes allowing tumor invasion and metastases formation. The aim of this study was to find a relationship between N- myc amplification and trace metals in human neuroblasts. Coupling PIXE and RBS techniques, nuclear microprobe allowed to analyze elemental distributions and to determine trace metal concentrations within cultured neuroblasts characterized by various degrees of N- myc amplification. They were compared to trace metal distributions and concentrations in tumor xenograft models of human NB, after injection of cells from the same lines in athymic nude mice. Our data allowed to establish a relation between trace metal contents and mechanisms of NB oncogenesis, amplified cell lines representing more aggressive phenotypes of the disease. They should be confirmed by analysis of cultured neuroblasts and tumors issued from a non-amplified cell line transfected with the N- myc oncogene.

  7. Trace metals and cancer: The case of neuroblastoma

    Energy Technology Data Exchange (ETDEWEB)

    Gouget, B. E-mail: gouget@drecam.cea.fr; Sergeant, C.; Llabador, Y.; Deves, G.; Vesvres, M.H.; Simonoff, M.; Benard, J

    2001-07-01

    N-myc oncogene amplification is one of the most established prognostic factors in neuroblastoma (NB), a young children solid tumor. Amounts of ferritin, an iron storage protein, are abnormally increased in serum of patients with advanced stage disease. N-myc amplified NB cells can synthesize zinc metalloenzymes allowing tumor invasion and metastases formation. The aim of this study was to find a relationship between N-myc amplification and trace metals in human neuroblasts. Coupling PIXE and RBS techniques, nuclear microprobe allowed to analyze elemental distributions and to determine trace metal concentrations within cultured neuroblasts characterized by various degrees of N-myc amplification. They were compared to trace metal distributions and concentrations in tumor xenograft models of human NB, after injection of cells from the same lines in athymic nude mice. Our data allowed to establish a relation between trace metal contents and mechanisms of NB oncogenesis, amplified cell lines representing more aggressive phenotypes of the disease. They should be confirmed by analysis of cultured neuroblasts and tumors issued from a non-amplified cell line transfected with the N-myc oncogene.

  8. The future of the "Homme-trace"

    Directory of Open Access Journals (Sweden)

    Béatrice Galinon-Mélénec

    2015-03-01

    Full Text Available Observant que la notion de trace est utilisée dans des disciplines aux objets et méthodes parfois très éloignés, l’auteure présente quelques définitions issues de ses propres recherches (Homme-trace, traces processuelles, traces perceptuelles, signe-trace, échoïsation des traces, signe-signal, etc. et propose des passerelles avec des recherches d’autres disciplines. Elles constituent une base de débats du e.laboratoire international et interdisciplinaire (Human-Trace-Complex Systems, laboratoire qui se donne pour objectif de faire émerger une intelligence collective de la notion de trace.

  9. Natural wetland emissions of methylated trace elements

    NARCIS (Netherlands)

    Vriens, B.; Lenz, M.; Charlet, L.; Berg, M.; Winkel, L.H.E.

    2014-01-01

    Natural wetlands are well known for their significant methane emissions. However, trace element emissions via biomethylation and subsequent volatilization from pristine wetlands are virtually unstudied, even though wetlands constitute large reservoirs for trace elements. Here we show that the averag

  10. Differential acetylcholine release in the prefrontal cortex and hippocampus during pavlovian trace and delay conditioning.

    Science.gov (United States)

    Flesher, M Melissa; Butt, Allen E; Kinney-Hurd, Brandee L

    2011-09-01

    Pavlovian trace conditioning critically depends on the medial prefrontal cortex (mPFC) and hippocampus (HPC), whereas delay conditioning does not depend on these brain structures. Given that the cholinergic basal forebrain system modulates activity in both the mPFC and HPC, it was reasoned that the level of acetylcholine (ACh) release in these regions would show distinct profiles during testing in trace and delay conditioning paradigms. To test this assumption, microdialysis probes were implanted unilaterally into the mPFC and HPC of rats that were pre-trained in appetitive trace and delay conditioning paradigms using different conditional stimuli in the two tasks. On the day of microdialysis testing, dialysate samples were collected during a quiet baseline interval before trials were initiated, and again during performance in separate blocks of trace and delay conditioning trials in each animal. ACh levels were quantified using high-performance liquid chromatography and electrochemical detection techniques. Consistent with our hypothesis, results showed that ACh release in the mPFC was greater during trace conditioning than during delay conditioning. The level of ACh released during trace conditioning in the HPC was also greater than the levels observed during delay conditioning. While ACh efflux in both the mPFC and HPC selectively increased during trace conditioning, ACh levels in the mPFC during trace conditioning testing showed the greatest increases observed. These results demonstrate a dissociation in cholinergic activation of the mPFC and HPC during performance in trace but not delay appetitive conditioning, where this cholinergic activity may contribute to attentional mechanisms, adaptive response timing, or memory consolidation necessary for successful trace conditioning.

  11. Distributed trace using central performance counter memory

    Science.gov (United States)

    Satterfield, David L.; Sexton, James C.

    2013-01-22

    A plurality of processing cores, are central storage unit having at least memory connected in a daisy chain manner, forming a daisy chain ring layout on an integrated chip. At least one of the plurality of processing cores places trace data on the daisy chain connection for transmitting the trace data to the central storage unit, and the central storage unit detects the trace data and stores the trace data in the memory co-located in with the central storage unit.

  12. Intensity of quartz cathodoluminescence and trace-element content in quartz from the porphyry copper deposit at Butte, Montana

    Science.gov (United States)

    Rusk, B.G.; Reed, M.H.; Dilles, J.H.; Kent, A.J.R.

    2006-01-01

    Textures of hydrothermal quartz revealed by cathodoluminescence using a scanning electron microscope (SEM-CL) reflect the physical and chemical environment of quartz formation. Variations in intensity of SEM-CL can be used to distinguish among quartz from superimposed mineralization events in a single vein. In this study, we present a technique to quantify the cathodoluminescent intensity of quartz within individual and among multiple samples to relate luminescence intensity to specific mineralizing events. This technique has been applied to plutonic quartz and three generations of hydrothermal veins at the porphyry copper deposit in Butte, Montana. Analyzed veins include early quartz-molybdenite veins with potassic alteration, pyrite-quartz veins with sericitic alteration, and Main Stage veins with intense sericitic alteration. CL intensity of quartz is diagnostic of each mineralizing event and can be used to fingerprint quartz and its fluid inclusions, isotopes, trace elements, etc., from specific mineralizing episodes. Furthermore, CL intensity increases proportional to temperature of quartz formation, such that plutonic quartz from the Butte quartz monzonite (BQM) that crystallized at temperatures near 750 ??C luminesces with the highest intensity, whereas quartz that precipitated at ???250 ??C in Main Stage veins luminesces with the least intensity. Trace-element analyses via electron microprobe and laser ablation-ICP-MS indicate that plutonic quartz and each generation of hydrothermal quartz from Butte is dominated by characteristic trace amounts of Al, P, Ti, and Fe. Thus, in addition to CL intensity, each generation of quartz can be distinguished based on its unique trace-element content. Aluminum is generally the most abundant element in all generations of quartz, typically between 50 and 200 ppm, but low-temperature, Main Stage quartz containing 400 to 3600 ppm Al is enriched by an order of magnitude relative to all other quartz generations. Phosphorous

  13. Nanosensors for trace explosive detection

    OpenAIRE

    2008-01-01

    Selective and sensitive detection of explosives is very important in countering terrorist threats. Detecting trace explosives has become a very complex and expensive endeavor because of a number of factors, such as the wide variety of materials that can be used as explosives, the lack of easily detectable signatures, the vast number of avenues by which these weapons can be deployed, and the lack of inexpensive sensors with high sensitivity and selectivity. High sensitivity and selectivity, co...

  14. Trace Explosives Detection by Photoluminescence

    OpenAIRE

    2004-01-01

    Some field tests in counter-terrorism efforts to detect explosive traces employ chemistries that yield colored products. We have examined a test kit of this kind, ETKPlus, based on widely used chemistries and employed extensively by the Israel Police. Our investigation focuses on the prospect of gaining sensitivity by replacing the normal colorimetric modality with photoluminescence detection, which, to our knowledge, has not been explored to date. We find two or more orders of magnitude sens...

  15. Dynamic Logic with Trace Semantics

    OpenAIRE

    Beckert, Bernhard; Bruns, Daniel

    2013-01-01

    Dynamic logic is an established instrument for program verification and for reasoning about the semantics of programs and programming languages. In this paper, we define an extension of dynamic logic, called Dynamic Trace Logic (DTL), which combines the expressiveness of program logics such as dynamic logic with that of temporal logic. And we present a sound and relatively complete sequent calculus for proving validity of DTL formulae. Due to its expressiveness, DTL can serve as a basis for p...

  16. Design of an expert system for mitigating trace element toxicity in cancer risk management.

    Science.gov (United States)

    Krishna Kumar, P T; Vinod, P T; Phoha, Vir V; Iyengar, S S; Iyengar, Puneeth

    2013-01-01

    Cancer risk management involves obliterating excess concentration of cancer causing trace elements by the natural immune system and hence intake of nutritious diet is of paramount importance. Human diet should consist of essential macronutrients that have to be consumed in large quantities and trace elements are to be consumed in very little amount. As some of these trace elements are causative factors for various types of cancer and build up at the expense of macronutrients, cancer risk management of these trace elements should be based on their initial concentration in the blood of each individual and not on their tolerable upper intake level. We propose an information theory based Expert System (ES) for estimating the lowest limit of toxicity association between the trace elements and the macronutrients. Such an estimate would enable the physician to prescribe required medication containing the macronutrients to annul the toxicity of cancer risk trace elements. The lowest limit of toxicity association is achieved by minimizing the correlated information of the concentration correlation matrix using the concept of Mutual Information (MI) and an algorithm based on a Technique of Determinant Inequalities (TDI) developed by the authors. The novelty of our ES is that it provides the lowest limit of toxicity profile for all trace elements in the blood not restricted to a group of compounds having similar structure. We demonstrate the superiority our algorithm over Principal Component Analysis in mitigating trace element toxicity in blood samples.

  17. Trace element emissions from coal

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-09-15

    Trace elements are emitted during coal combustion. The quantity, in general, depends on the physical and chemical properties of the element itself, the concentration of the element in the coal, the combustion conditions and the type of particulate control device used, and its collection efficiency as a function of particle size. Some trace elements become concentrated in certain particle streams following combustion such as bottom ash, fly ash, and flue gas particulate matter, while others do not. Various classification schemes have been developed to describe this partitioning behaviour. These classification schemes generally distinguish between: Class 1: elements that are approximately equally concentrated in the fly ash and bottom ash, or show little or no fine particle enrichment, examples include Mn, Be, Co and Cr; Class 2: elements that are enriched in the fly ash relative to bottom ash, or show increasing enrichment with decreasing particle size, examples include As, Cd, Pb and Sb; Class 3: elements which are emitted in the gas phase (primarily Hg (not discussed in this review), and in some cases, Se). Control of class 1 trace elements is directly related to control of total particulate matter emissions, while control of the class 2 elements depends on collection of fine particulates. Due to the variability in particulate control device efficiencies, emission rates of these elements can vary substantially. The volatility of class 3 elements means that particulate controls have only a limited impact on the emissions of these elements.

  18. Trace anomalies from quantum mechanics

    CERN Document Server

    Bastianelli, F; Bastianelli, Fiorenzo; Nieuwenhuizen, Peter van

    1993-01-01

    The 1-loop anomalies of a d-dimensional quantum field theory can be computed by evaluating the trace of the regulated path integral jacobian matrix, as shown by Fujikawa. In 1983, Alvarez-Gaum\\'e and Witten observed that one can simplify this evaluation by replacing the operators which appear in the regulator and in the jacobian by quantum mechanical operators with the same (anti)commutation relations. By rewriting this quantum mechanical trace as a path integral with periodic boundary conditions for a one-dimensional supersymmetric nonlinear sigma model, they obtained the chiral anomalies for spin 1/2 and 3/2 fields and selfdual antisymmetric tensors in d dimensions. In this article, we treat the case of trace anomalies for spin 0, 1/2 and 1 fields in a gravitational and Yang-Mills background. We do not introduce a supersymmetric sigma model, but keep the original Dirac matrices $\\g^\\m$ and internal symmetry generators $T^a$ in the path integral. As a result, we get a matrix-valued action. Gauge covariance o...

  19. SNMP Trace Analysis Definitions

    NARCIS (Netherlands)

    Broek, van den G.; Schoenwaelder, J.; Pras, A.; Harvan, M.

    2008-01-01

    The Network Management Research Group (NMRG) started an activity to collect traces of the Simple Network Management Protocol (SNMP) from operational networks. To analyze these traces, it is necessary to split potentially large traces into more manageable pieces that make it easier to deal with lar

  20. Fiber: How to Increase the Amount in Your Diet

    Science.gov (United States)

    ... Fiber: How to Increase the Amount in Your Diet Fiber: How to Increase the Amount in Your Diet ... in the digestive tract) and irritable bowel syndrome. Dietary fiber may also help lower your cholesterol and reduce ...

  1. 42 CFR 410.152 - Amounts of payment.

    Science.gov (United States)

    2010-10-01

    ... (insofar as reasonable) charges of the CAH for the services. (l) Amount of payment: Flu vaccine. Medicare... reasonable charge. (h) Amount of payment: Pneumococcal vaccine. Medicare Part B pays for pneumococcal...

  2. 13 CFR 108.2020 - Amount of Operational Assistance grant.

    Science.gov (United States)

    2010-01-01

    .... (c) Pro rata reductions. In the event that the total amount of funds available to SBA for purposes of... in the amounts described in paragraphs (a) and (b) of this section, SBA will make pro rata...

  3. A robust and reliable optical trace oxygen sensor

    Science.gov (United States)

    McDowell, G. R.; Holmes-Smith, A. S.; Uttamlal, M.; Mitchell, C.; Shannon, P. H.

    2017-05-01

    In applications of nitrogen (N2) generation, industrial gas manufacturing and food packaging there is a need to ensure oxygen (O2) is absent from the environment, even at the lowest concentration levels. Therefore, there has been an increased growth in the development of trace O2 parts per million (ppm) sensors over the past decade to detect and quantify the concentration of molecular O2 in the environment whether it be dissolved or gaseous O2. The majority of commercially available trace O2 sensors are based on electrochemical, zirconia and paramagnetic technologies. Here, the development of a luminescence-based optical trace O2 sensor is presented. Luminescence-based sensing is now regarded as one of the best techniques for the detection and quantification of O2. This is due to the high detection sensitivity, no O2 is consumed and there are a vast array of luminescent indicators and sensing platforms (polymers) that can be selected to suit the desired application. The sensor will be shown to operate from -30 °C to +60 °C in the 0-1000 ppm and/or 0-1200 μbar partial pressure of oxygen (ppO2) range and is equipped with temperature and pressure compensation. The luminescence non-depleting principle, sensor specifications and miniaturized nature offers an attractive alternative to other sensing technologies and advantages over other luminescence-based O2 ppm sensors.

  4. 20 CFR 617.13 - Weekly amounts of TRA.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Weekly amounts of TRA. 617.13 Section 617.13... FOR WORKERS UNDER THE TRADE ACT OF 1974 Trade Readjustment Allowances (TRA) § 617.13 Weekly amounts of TRA. (a) Regular allowance. The amount of TRA payable for a week of total unemployment (including a...

  5. 20 CFR 617.14 - Maximum amount of TRA.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Maximum amount of TRA. 617.14 Section 617.14... FOR WORKERS UNDER THE TRADE ACT OF 1974 Trade Readjustment Allowances (TRA) § 617.14 Maximum amount of TRA. (a) General rule. Except as provided under paragraph (b) of this section, the maximum amount of...

  6. 12 CFR 1806.202 - Estimated award amounts.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Estimated award amounts. 1806.202 Section 1806... BANK ENTERPRISE AWARD PROGRAM Awards § 1806.202 Estimated award amounts. (a) General. An Applicant shall calculate and submit to the Fund an estimated award amount as part of the Bank Enterprise...

  7. 14 CFR 198.7 - Amount of insurance coverage available.

    Science.gov (United States)

    2010-01-01

    ... (CONTINUED) WAR RISK INSURANCE AVIATION INSURANCE § 198.7 Amount of insurance coverage available. (a) For... arising from any risk. In the case of hull insurance, the amount insured may not exceed the reasonable... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Amount of insurance coverage available....

  8. 7 CFR 1710.107 - Amount lent for acquisitions.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 11 2010-01-01 2010-01-01 false Amount lent for acquisitions. 1710.107 Section 1710... GUARANTEES Loan Purposes and Basic Policies § 1710.107 Amount lent for acquisitions. The maximum amount that will be lent for an acquisition is limited to the value of the property, as determined by RUS. If the...

  9. 12 CFR 347.120 - Computation of investment amounts.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 4 2010-01-01 2010-01-01 false Computation of investment amounts. 347.120... GENERAL POLICY INTERNATIONAL BANKING § 347.120 Computation of investment amounts. In computing the amount that may be invested in any foreign organization under §§ 347.117 through 347.119, any investments...

  10. 42 CFR 57.2207 - Amount of scholarship grant.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Amount of scholarship grant. 57.2207 Section 57... CONSTRUCTION OF TEACHING FACILITIES, EDUCATIONAL IMPROVEMENTS, SCHOLARSHIPS AND STUDENT LOANS Physician Shortage Area Scholarship Grants § 57.2207 Amount of scholarship grant. (a) The amount of the...

  11. 41 CFR 105-56.029 - Offset amount.

    Science.gov (United States)

    2010-07-01

    ... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Offset amount. 105-56... Administration 56-SALARY OFFSET FOR INDEBTEDNESS OF FEDERAL EMPLOYEES TO THE UNITED STATES Centralized Salary Offset (CSO) Procedures-GSA as Paying Agency § 105-56.029 Offset amount. (a) The minimum dollar amount...

  12. Quantifying robustness of biochemical network models

    Directory of Open Access Journals (Sweden)

    Iglesias Pablo A

    2002-12-01

    Full Text Available Abstract Background Robustness of mathematical models of biochemical networks is important for validation purposes and can be used as a means of selecting between different competing models. Tools for quantifying parametric robustness are needed. Results Two techniques for describing quantitatively the robustness of an oscillatory model were presented and contrasted. Single-parameter bifurcation analysis was used to evaluate the stability robustness of the limit cycle oscillation as well as the frequency and amplitude of oscillations. A tool from control engineering – the structural singular value (SSV – was used to quantify robust stability of the limit cycle. Using SSV analysis, we find very poor robustness when the model's parameters are allowed to vary. Conclusion The results show the usefulness of incorporating SSV analysis to single parameter sensitivity analysis to quantify robustness.

  13. Combinatorics of traces of Hecke operators.

    Science.gov (United States)

    Frechette, Sharon; Ono, Ken; Papanikolas, Matthew

    2004-12-01

    We investigate the combinatorial properties of the traces of the nth Hecke operators on the spaces of weight 2k cusp forms of level N. We establish examples in which these traces are expressed in terms of classical objects in enumerative combinatorics (e.g., tilings and Motzkin paths). We establish in general that Hecke traces are explicit rational linear combinations of values of Gegenbauer (also known as ultraspherical) polynomials. These results arise from "packaging" the Hecke traces into power series in weight aspect. These generating functions are easily computed by using the Eichler-Selberg trace formula.

  14. Photoluminescent Detection of Dissolved Underwater Trace Explosives

    Directory of Open Access Journals (Sweden)

    Tye Langston

    2010-01-01

    Full Text Available A portable, rapid, and economical method for in situ trace explosive detection in aqueous solutions was demonstrated using photoluminescence. Using europium/thenoyltrifluoroacetone as the reagent, dissolved nitroglycerin was fluorescently tagged and detected in seawater solutions without sample preparation, drying, or preconcentration. The chemical method was developed in a laboratory setting and demonstrated in a flow-through configuration using lightweight, inexpensive, commercial components by directly injecting the reagents into a continually flowing seawater stream using a small amount of organic solvent (approximately 8% of the total solution. Europium's vulnerability to vibrational fluorescence quenching by water provided the mode of detection. Without nitroglycerin in the seawater solution, the reagent's fluorescence was quenched, but when dissolved nitroglycerin was present, it displaced the water molecules from the europium/thenoyltrifluoroacetone compound and restored fluorescence. This effort focused on developing a seawater sensor, but performance comparisons were made to freshwater. The method was found to perform better in freshwater and it was shown that certain seawater constituents (such as calcium have an adverse impact. However, the concentrations of these constituents are not expected to vary significantly from the natural seawater used herein.

  15. Regional distribution and losses of end-of-life steel throughout multiple product life cycles-Insights from the global multiregional MaTrace model.

    Science.gov (United States)

    Pauliuk, Stefan; Kondo, Yasushi; Nakamura, Shinichiro; Nakajima, Kenichi

    2017-01-01

    Substantial amounts of post-consumer scrap are exported to other regions or lost during recovery and remelting, and both export and losses pose a constraint to desires for having regionally closed material cycles. To quantify the challenges and trade-offs associated with closed-loop metal recycling, we looked at the material cycles from the perspective of a single material unit and trace a unit of material through several product life cycles. Focusing on steel, we used current process parameters, loss rates, and trade patterns of the steel cycle to study how steel that was originally contained in high quality applications such as machinery or vehicles with stringent purity requirements gets subsequently distributed across different regions and product groups such as building and construction with less stringent purity requirements. We applied MaTrace Global, a supply-driven multiregional model of steel flows coupled to a dynamic stock model of steel use. We found that, depending on region and product group, up to 95% of the steel consumed today will leave the use phase of that region until 2100, and that up to 50% can get lost in obsolete stocks, landfills, or slag piles until 2100. The high losses resulting from business-as-usual scrap recovery and recycling can be reduced, both by diverting postconsumer scrap into long-lived applications such as buildings and by improving the recovery rates in the waste management and remelting industries. Because the lifetimes of high-quality (cold-rolled) steel applications are shorter and remelting occurs more often than for buildings and infrastructure, we found and quantified a tradeoff between low losses and high-quality applications in the steel cycle. Furthermore, we found that with current trade patterns, reduced overall losses will lead to higher fractions of secondary steel being exported to other regions. Current loss rates, product lifetimes, and trade patterns impede the closure of the steel cycle.

  16. Relationship between sample loading amount and peptide identification and its effects on quantitative proteomics.

    Science.gov (United States)

    Liu, Kehui; Zhang, Jiyang; Wang, Jinglan; Zhao, Liyan; Peng, Xu; Jia, Wei; Ying, Wantao; Zhu, Yunping; Xie, Hongwei; He, Fuchu; Qian, Xiaohong

    2009-02-15

    The relationship between sample loading amount and peptide identification is crucial for the optimization of proteomics experiments, but few studies have addressed this matter. Herein, we present a systematic study using a replicate run strategy to probe the inherent influence of both peptide physicochemical properties and matrix effects on the relationship between peptide identification and sample loading amounts, as well as its applications in protein quantification. Ten replicate runs for a series of laddered loading amounts (ranging between 0.01 approximately 10 microg) of total digested proteins from Saccharomyces cerevisiae were performed with nanoscale liquid chromatography coupled with linear ion trap/Fourier transform ion cyclotron resonance (nanoLC-LTQ-FT) to obtain a nearly saturated peptide identification. This permitted us to differentiate the linear correlativity of peptide identification by the commonly used peptide quantitative index, the area of constructed ion chromatograms (XIC) (SA, from MS and tandem MS data) in the given experiments. The absolute loading amount of a given complex sample affected the final qualitative identification result; thus, optimization of the sample loading amount before every proteomics study was essential. Peptide physicochemical properties had little effect on the linear correlativity between SA-based peptide quantification and loading amount. The matrix effects, rather than the static physicochemical properties of individual peptides, affect peptide measurability. We also quantified the target protein by selecting peptides with good parallel linear correlativity based upon SA as signature peptides and revised the data by multiplying by the reciprocal of the slope coefficient. We found that this optimized the linear protein abundance relativity at every amount range and thus extended the linear dynamic range of label-free quantification. This empirical rule for linear peptide selection (ERLPS) can be adopted to

  17. Interaction of chemical species with biological regulation of the metabolism of essential trace elements

    Energy Technology Data Exchange (ETDEWEB)

    Windisch, W. [Center of Life and Food Sciences, Technische Univ. Muenchen, Freising (Germany)

    2002-02-01

    Variations in the chemical speciation of dietary trace elements can result in the provision of different amounts of these micronutrients to the organism and might thus induce interactions with trace-element metabolism. The chemical species of Zn, Fe, Cu, and Mn can interact with other components of the diet even before reaching the site of absorption, e.g. by formation of poorly soluble complexes with phytic acid. This might considerably modify the amount of metabolically available trace elements; differences between absorptive capacity per se toward dietary species seems to be less important. Homeostasis usually limits the quantities of Zn, Fe, Cu, and Mn transported from the gut into the organism, and differences between dietary species are largely eliminated at this step. There is no homeostatic control of absorption of Se and I, and organisms seem to be passively exposed to influx of these micronutrients irrespective of dietary speciation. Inside the organism the trace elements are usually converted into a metabolically recognizable form, channeled into their biological functions, or submitted to homeostatically controlled excretion. Some dietary species can, however, be absorbed as intact compounds. As long as the respective quantities of trace elements are not released from their carriers, they are not recognized properly by trace element metabolism and might induce tissue accumulation, irrespective of homeostatic control. (orig.)

  18. Tracing Technique for Blaster Attack

    CERN Document Server

    S., Siti Rahayu; S., Shahrin; A., Faizal M; M, Mohd Zaki; R, Irda

    2009-01-01

    Blaster worm of 2003 is still persistent, the infection appears to have successfully transitioned to new hosts as the original systems are cleaned or shut off, suggesting that the Blaster worm, and other similar worms, will remain significant Internet threats for many years after their initial release. This paper is to propose technique on tracing the Blaster attack from various logs in different OSI layers based on fingerprint of Blaster attack on victim logs, attacker logs and IDS alert log. The researchers intended to do a preliminary investigation upon this particular attack so that it can be used for further research in alert correlation and computer forensic investigation.

  19. A Note on Trace Polynomial

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper, we mainly study the relation of two cyclically reduced words w and w' on the condition they have the same trace polynomial (i.e., tr w= tr w' ). By defining an equivalence relation through such operators on words as inverse, cyclically left shift, and mirror, it is straightforward to get that w ~ w' implies tr w = tr w'. We show by a counter example that tr w = tr w' does not imply w ~ w'. And in two special cases, we prove that tr w = tr w' if and only if w ~ w'.

  20. Learning, tracing, and risk dominance

    DEFF Research Database (Denmark)

    Hendon, Ebbe; Jacobsen, Hans Jørgen; Nielsen, Michael Teit;

    1994-01-01

    This paper presents a learning process which is a generalization of the method of fictitious play of Brown. If the learning process converges, the convergence point is a Nash equilibrium. We study 2 × 2 games. Here the process always converges. The relation between the initial prior, the weight...... assigned to this prior, and the equilibrium selected is examined. As the weight increases, the relation between the prior and the equilibrium selected becomes almost identical to that of the tracing procedure of Harsanyi. In this way the learning process supports the concept of risk dominance of Harsanyi...

  1. IONORT: IONOsphere Ray-Tracing

    OpenAIRE

    Bianchi, C.; Settimi, A; Azzarone, A.

    2010-01-01

    Il pacchetto applicativo “IONORT” per il calcolo del ray-tracing può essere utilizzato dagli utenti che impiegano il sistema operativo Windows. È un programma la cui interfaccia grafica con l’utente è realizzata in MATLAB. In realtà, il programma lancia un eseguibile che integra il sistema d’equazioni differenziali scritto in linguaggio Fortran e ne importa l’output nel programma MATLAB, il quale genera i grafici e altre informazioni sul raggio. A completamento di questa premessa va detto ...

  2. Quantifying brain microstructure with diffusion MRI

    DEFF Research Database (Denmark)

    Novikov, Dmitry S.; Jespersen, Sune N.; Kiselev, Valerij G.

    2016-01-01

    We review, systematize and discuss models of diffusion in neuronal tissue, by putting them into an overarching physical context of coarse-graining over an increasing diffusion length scale. From this perspective, we view research on quantifying brain microstructure as occurring along the three ma...

  3. Quantifying the Reuse of Learning Objects

    Science.gov (United States)

    Elliott, Kristine; Sweeney, Kevin

    2008-01-01

    This paper reports the findings of one case study from a larger project, which aims to quantify the claimed efficiencies of reusing learning objects to develop e-learning resources. The case study describes how an online inquiry project "Diabetes: A waste of energy" was developed by searching for, evaluating, modifying and then…

  4. QS Spiral: Visualizing Periodic Quantified Self Data

    DEFF Research Database (Denmark)

    Larsen, Jakob Eg; Cuttone, Andrea; Jørgensen, Sune Lehmann

    2013-01-01

    In this paper we propose an interactive visualization technique QS Spiral that aims to capture the periodic properties of quantified self data and let the user explore those recurring patterns. The approach is based on time-series data visualized as a spiral structure. The interactivity includes ...

  5. Basinsoft, a computer program to quantify drainage basin characteristics

    Science.gov (United States)

    Harvey, Craig A.; Eash, David A.

    2001-01-01

    Surface water runoff is a function of many interrelated factors including climate, soils, landuse, and the physiography of the drainage basin. A practical and effective method to quantify drainage basin characteristics would allow analysis of the interrelations of these factors, leading to an improved understanding of the effects of drainage basin characteristics on surface-water runoff. Historically, the quantification of drainage basin characteristics has been a tedious and time-consuming process. Recent improvements in computer hardware and software technology have enabled the developers of a program called Basinsoft to automate this process. Basinsoft requires minimal preprocessing of data and provides an efficient, automated procedure for quantifying selected morphometric characteristics and the option to area-weight characteristics for a drainage basin. The user of Basinsoft is assumed to have a limited amount of experience in the use of ARC/INFO, a proprietary geographic information system (GIS). (The use of brand names in this chapter is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey [USGS].)

  6. Quantifying historical carbon and climate debts among nations

    Science.gov (United States)

    Matthews, H. Damon

    2016-01-01

    Contributions to historical climate change have varied substantially among nations. These differences reflect underlying inequalities in wealth and development, and pose a fundamental challenge to the implementation of a globally equitable climate mitigation strategy. This Letter presents a new way to quantify historical inequalities among nations using carbon and climate debts, defined as the amount by which national climate contributions have exceeded a hypothetical equal per-capita share over time. Considering only national CO2 emissions from fossil fuel combustion, accumulated carbon debts across all nations from 1990 to 2013 total 250 billion tonnes of CO2, representing 40% of cumulative world emissions since 1990. Expanding this to reflect the temperature response to a range of emissions, historical climate debts accrued between 1990 and 2010 total 0.11 °C, close to a third of observed warming over that period. Large fractions of this debt are carried by industrialized countries, but also by countries with high levels of deforestation and agriculture. These calculations could contribute to discussions of climate responsibility by providing a tangible way to quantify historical inequalities, which could then inform the funding of mitigation, adaptation and the costs of loss and damages in those countries that have contributed less to historical warming.

  7. Measuring Traces Of Oxygen By Resonant Electron Attachment

    Science.gov (United States)

    Man, Kin Fung; Boumsellek, Said; Chutjian, Ara

    1995-01-01

    Method of detecting trace amounts of oxygen based on dissociative attachment of electrons to oxygen molecules followed by measurement of resulting flux of negative oxygen ions in mass spectrometer. High sensitivity achieved in method by exploiting resonance in dissociative attachment of electrons to oxygen molecules: electron-attachment cross section rises to high peak at incident electron kinetic energy of 6.2 eV. Relative concentrations below 1 ppb detected. Devised to increase sensitivity of detection of oxygen in processing chambers in which oxygen regarded as contaminant; for example, chambers used in making semiconductor devices and in growing high-purity crystals.

  8. Trace detection of analytes using portable raman systems

    Science.gov (United States)

    Alam, M. Kathleen; Hotchkiss, Peter J.; Martin, Laura E.; Jones, David Alexander

    2015-11-24

    Apparatuses and methods for in situ detection of a trace amount of an analyte are disclosed herein. In a general embodiment, the present disclosure provides a surface-enhanced Raman spectroscopy (SERS) insert including a passageway therethrough, where the passageway has a SERS surface positioned therein. The SERS surface is configured to adsorb molecules of an analyte of interest. A concentrated sample is caused to flow over the SERS surface. The SERS insert is then provided to a portable Raman spectroscopy system, where it is analyzed for the analyte of interest.

  9. The geochemistry of environmentally important trace elements in UK coals, with special reference to the Parkgate coal in the Yorkshire-Nottinghamshire Coalfield, UK

    Science.gov (United States)

    Spears, D.A.; Tewalt, S.J.

    2009-01-01

    The Parkgate coal of Langsettian age in the Yorkshire-Nottinghamshire coalfield is typical of many coals in the UK in that it has a high sulphur (S) content. Detailed information on the distribution of the forms of S, both laterally and vertically through the seam, was known from previous investigations. In the present work, 38 interval samples from five measured sections of the coal were comprehensively analysed for major, minor and trace elements and the significance of the relationships established using both raw and centered log transformed data. The major elements are used to quantify the variations in the inorganic and organic coal components and determine the trace element associations. Pyrite contains nearly all of the Hg, As, Se, Tl and Pb and is also the major source of the Mo, Ni, Cd and Sb. The clays contain the following elements in decreasing order of association: Rb, Cs, Li, Ga, U, Cr, V, Sc, Y, Bi, Cu, Nb, Sn, Te and Th. Nearly all of the Rb is present in the clay fraction, whereas for elements such as V, Cu and U, a significant amount is thought to be present in the organic matter, based on the K vs trace element regression equations. Only Ge, and possibly Be, would appear to have a dominant organic source. The trace element concentrations are calculated for pyrite, the clay fraction and organic matter. For pyrite it is noted that concentrations agree with published data from the Yorkshire-Nottinghamshire coalfield and also that Tl concentrations (median of 0.33 ppm) in the pyrite are greater than either Hg or Cd. Unlike these elements, Tl has attracted less attention and possibly more information is needed on its anthropogenic distribution and impacts on man and the environment. A seawater source is thought to be responsible for the high concentrations of S, Cl and the non-detrital trace elements in the Parkgate coal. Indicative of the seawater control is the Th/U ratio, which expresses the detrital to non-detrital element contributions. Using

  10. Variation in Macro and Trace Elements in Progression of Type 2 Diabetes

    Directory of Open Access Journals (Sweden)

    Khalid Siddiqui

    2014-01-01

    Full Text Available Macro elements are the minerals of which the body needs more amounts and are more important than any other elements. Trace elements constitute a minute part of the living tissues and have various metabolic characteristics and functions. Trace elements participate in tissue and cellular and subcellular functions; these include immune regulation by humoral and cellular mechanisms, nerve conduction, muscle contractions, membrane potential regulations, and mitochondrial activity and enzyme reactions. The status of micronutrients such as iron and vanadium is higher in type 2 diabetes. The calcium, magnesium, sodium, chromium, cobalt, iodine, iron, selenium, manganese, and zinc seem to be low in type 2 diabetes while elements such as potassium and copper have no effect. In this review, we emphasized the status of macro and trace elements in type 2 diabetes and its advantages or disadvantages; this helps to understand the mechanism, progression, and prevention of type 2 diabetes due to the lack and deficiency of different macro and trace elements.

  11. Program Instrumentation and Trace Analysis

    Science.gov (United States)

    Havelund, Klaus; Goldberg, Allen; Filman, Robert; Rosu, Grigore; Koga, Dennis (Technical Monitor)

    2002-01-01

    Several attempts have been made recently to apply techniques such as model checking and theorem proving to the analysis of programs. This shall be seen as a current trend to analyze real software systems instead of just their designs. This includes our own effort to develop a model checker for Java, the Java PathFinder 1, one of the very first of its kind in 1998. However, model checking cannot handle very large programs without some kind of abstraction of the program. This paper describes a complementary scalable technique to handle such large programs. Our interest is turned on the observation part of the equation: How much information can be extracted about a program from observing a single execution trace? It is our intention to develop a technology that can be applied automatically and to large full-size applications, with minimal modification to the code. We present a tool, Java PathExplorer (JPaX), for exploring execution traces of Java programs. The tool prioritizes scalability for completeness, and is directed towards detecting errors in programs, not to prove correctness. One core element in JPaX is an instrumentation package that allows to instrument Java byte code files to log various events when executed. The instrumentation is driven by a user provided script that specifies what information to log. Examples of instructions that such a script can contain are: 'report name and arguments of all called methods defined in class C, together with a timestamp'; 'report all updates to all variables'; and 'report all acquisitions and releases of locks'. In more complex instructions one can specify that certain expressions should be evaluated and even that certain code should be executed under various conditions. The instrumentation package can hence be seen as implementing Aspect Oriented Programming for Java in the sense that one can add functionality to a Java program without explicitly changing the code of the original program, but one rather writes an

  12. Improving Ion Mobility Spectrometry Detection Methods for Trace Forensics and Military Field Applications

    Science.gov (United States)

    2016-10-11

    and sample vapors are carried into the column. In the positive setting, a trace amount of nicotinamide is automatically added into the...1980-1990, Critical Reviews Analytical Chemistry 1991, 22, 17-36. (32) Nanji, A. A.; Lawerence, A. H.; Mikhael, N. Z. Use of skins sampling and

  13. Derivatization in gas chromatographic determination of phenol and aniline traces in aqueous media

    Science.gov (United States)

    Gruzdev, I. V.; Zenkevich, I. G.; Kondratenok, B. M.

    2015-06-01

    Substituted anilines and phenols are the most common hydrophilic organic environmental toxicants. The principles of gas chromatographic determination of trace amounts of these compounds in aqueous media at concentrations extractive preconcentration and selective chromatographic detection. Among the known reactions, this condition is best met by electrophilic halogenation of compounds at the aromatic moiety. The bibliography includes 177 references.

  14. Exploiting flow Injection and sequential injection schemes for trace metal determinations by electrothermal atomic absorption spectrometry

    DEFF Research Database (Denmark)

    Hansen, Elo Harald

    Determination of low or trace-level amounts of metals by electrothermal atomic absorption spectrometry (ETAAS) often requires the use of suitable preconcentration and/or separation procedures in order to attain the necessary sensitivity and selectivity. Such schemes are advantageously executed...

  15. Trace metals in suspended particulate matter and sediments from the Severnaya Dvina estuary, Russian Arctic

    NARCIS (Netherlands)

    Koukina, S.E.; Calafat-Frau, A.; Hummel, H.; Palerud, R.

    2001-01-01

    A geochemical study of the Severnaya Dvina estuary was carried out during two oceanographic cruises to the White Sea. The amount and distribution of trace (Mn, Co, Cu, Ni, Pb, and Zn) and major (Al and Fe) elements in suspended particulate matter and sediments were determined. The main source of

  16. Intermittent exposure to traces of green leaf volatiles trigger a plant response

    NARCIS (Netherlands)

    Shiojiri, K.; Ozawa, R.; Matsui, K.; Sabelis, M.W.; Takabayashi, J.

    2012-01-01

    Plants are known to mount a defensive response when exposed to volatile chemicals from other plants, but the critical concentration required for this response is not known. We showed that intermittent exposure over a period of 3 weeks to trace amounts (less than 140 pptV) of green leaf volatiles emi

  17. Dietary composition affect levels of trace elements in the predator Podisus maculiventris (Say) (Heteroptera: Pentatomidae)

    Science.gov (United States)

    Insects require small amounts of dietary minerals because of the roles minerals serve as antioxidants, enzyme co-factors and as constituents of metalloproteins. We measured the levels of ten trace elements (Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Se and Zn) in the predatory insect, Podisus maculiventris rea...

  18. Lanthanide-labeled clay: A new method for tracing sediment transport in Karst

    Science.gov (United States)

    Mahler, B.J.; Bennett, P.C.; Zimmerman, M.

    1998-01-01

    Mobile sediment is a fundamental yet poorly characterized aspect of mass transport through karst aquifers. Here the development and field testing of an extremely sensitive particle tracer that may be used to characterize sediment transport in karst aquifers is described. The tracer consists of micron-size montmorillonite particles homoionized to the lanthanide form; after injection and retrieval from a ground water system, the lanthanide ions are chemically stripped from the clay and quantified by high performance liquid chromatography. The tracer meets the following desired criteria: low detection limit; a number of differentiable signatures; inexpensive production and quantification using standard methods; no environmental risks; and hydrodynamic properties similar to the in situ sediment it is designed to trace. The tracer was tested in laboratory batch experiments and field tested in both surface water and ground water systems. In surface water, arrival times of the tracer were similar to those of a conservative water tracer, although a significant amount of material was lost due to settling. Two tracer tests were undertaken in a karst aquifer under different flow conditions. Under normal flow conditions, the time of arrival and peak concentration of the tracer were similar to or preceded that of a conservative water tracer. Under low flow conditions, the particle tracer was not detected, suggesting that in low flow the sediment settles out of suspension and goes into storage.Mobile sediment is a fundamental yet poorly characterized aspect of mass transport through karst aquifers. Here the development and field testing of an extremely sensitive particle tracer that may be used to characterize sediment transport in karst aquifers is described. The tracer consists of micron-size montmorillonite particles homoionized to the lanthanide form; after injection and retrieval from a ground water system, the lanthanide ions are chemically stripped from the clay and

  19. Spectroscopic characterization of digestates obtained from sludge mixed to increasing amounts of fruit and vegetable wastes

    Science.gov (United States)

    Provenzano, Maria Rosaria; Cavallo, Ornella; Malerba, Anna Daniela; Di Maria, Francesco; Ricci, Anna; Gigliotti, Giovanni

    2015-04-01

    Anaerobic digestion (AD) represents an efficient waste-treatment technology during which microorganisms break down biodegradable material in absence of oxygen yielding a biogas containing methane. The aim of this work was to investigate the transformations occurring in the organic matter during the co-digestion of waste mixed sludge (WMS) with an increasing amount of fruit and vegetable wastes (FVW) in a pilot scale apparatus reproducing a full-scale digester in an existing wastewater treatment plant. Samples comprised: sludge, FVW, sludge mixed with 10-20-30-40% FVW. Ingestates and digestates were analyzed by means of emission fluorescence spectroscopy and FTIR associated to Fourier self deconvolution (FSD) of spectra. With increasing the amount of FVW from 10% to 20% at which percentage biogas production reached the maximum value, FTIR spectra and FSD traces of digestates exhibited a decrease of intensity of peaks assigned to polysaccharides and aliphatics and an increase of peak assigned to aromatics as a result of the biodegradation of rapidly degradable materials and concentration of aromatic recalcitrant compounds. Digestates with 30 and 40% FVW exhibited a relative increase of intensity of peaks assigned to aliphatics likely as a result of the increasing amount of rapidly degradable materials and the consequent reduction of the hydraulic retention time. This may cause inhibition of methanogenesis and accumulation of volatile fatty acids. The highest emission fluorescence intensity was observed for the digestate with 20% FVW confirming the concentration of aromatic recalcitrant compounds in the substrate obtained at the highest biogas production.

  20. Quantifying the Colour-Dependent Stochasticity of Large-Scale Structure

    CERN Document Server

    Patej, Anna

    2015-01-01

    We address the question of whether massive red and blue galaxies trace the same large-scale structure at z~0.6 using the CMASS sample of galaxies from Data Release 12 of the Sloan Digital Sky Survey III. After splitting the catalog into subsamples of red and blue galaxies using a simple colour cut, we measure the clustering of both subsamples and construct the correlation coefficient, r, using two statistics. The correlation coefficient quantifies the stochasticity between the two subsamples, which we examine over intermediate scales (20 0.95 taking into account both statistics and r > 0.974 using the favored statistic.

  1. Quantifying the entropic cost of cellular growth control

    Science.gov (United States)

    De Martino, Daniele; Capuani, Fabrizio; De Martino, Andrea

    2017-07-01

    Viewing the ways a living cell can organize its metabolism as the phase space of a physical system, regulation can be seen as the ability to reduce the entropy of that space by selecting specific cellular configurations that are, in some sense, optimal. Here we quantify the amount of regulation required to control a cell's growth rate by a maximum-entropy approach to the space of underlying metabolic phenotypes, where a configuration corresponds to a metabolic flux pattern as described by genome-scale models. We link the mean growth rate achieved by a population of cells to the minimal amount of metabolic regulation needed to achieve it through a phase diagram that highlights how growth suppression can be as costly (in regulatory terms) as growth enhancement. Moreover, we provide an interpretation of the inverse temperature β controlling maximum-entropy distributions based on the underlying growth dynamics. Specifically, we show that the asymptotic value of β for a cell population can be expected to depend on (i) the carrying capacity of the environment, (ii) the initial size of the colony, and (iii) the probability distribution from which the inoculum was sampled. Results obtained for E. coli and human cells are found to be remarkably consistent with empirical evidence.

  2. Impact of deep convection on the isotopic amount effect in tropical precipitation

    Science.gov (United States)

    Tharammal, Thejna; Bala, Govindasamy; Noone, David

    2017-02-01

    The empirical "amount effect" observed in the distribution of stable water isotope ratios in tropical precipitation is used in several studies to reconstruct past precipitation. Recent observations suggest the importance of large-scale organized convection systems on amount effect. With a series of experiments with Community Atmospheric Model version 3.0 with water isotope tracers, we quantify the sensitivity of amount effect to changes in modeled deep convection. The magnitude of the regression slope between long-term monthly precipitation amount and isotope ratios in precipitation over tropical ocean reduces by more than 20% with a reduction in mean deep convective precipitation by about 60%, indicating a decline in fractionation efficiency. Reduced condensation in deep convective updrafts results in enrichment of lower level vapor with heavier isotope that causes enrichment in total precipitation. However, consequent increases in stratiform and shallow convective precipitation partially offset the reduction in the slope of amount effect. The net result is a reduced slope of amount effect in tropical regions except the tropical western Pacific, where the effects of enhanced large-scale ascent and increased stratiform precipitation prevail over the influence of reduced deep convection. We also find that the isotope ratios in precipitation are improved over certain regions in the tropics with reduced deep convection, showing that analyses of isotope ratios in precipitation and water vapor are powerful tools to improve precipitation processes in convective parameterization schemes in climate models. Further, our study suggests that the precipitation types over a region can alter the fractionation efficiency of isotopes with implications for the reconstructions of past precipitation.

  3. Quantifying Stock Return Distributions in Financial Markets.

    Science.gov (United States)

    Botta, Federico; Moat, Helen Susannah; Stanley, H Eugene; Preis, Tobias

    2015-01-01

    Being able to quantify the probability of large price changes in stock markets is of crucial importance in understanding financial crises that affect the lives of people worldwide. Large changes in stock market prices can arise abruptly, within a matter of minutes, or develop across much longer time scales. Here, we analyze a dataset comprising the stocks forming the Dow Jones Industrial Average at a second by second resolution in the period from January 2008 to July 2010 in order to quantify the distribution of changes in market prices at a range of time scales. We find that the tails of the distributions of logarithmic price changes, or returns, exhibit power law decays for time scales ranging from 300 seconds to 3600 seconds. For larger time scales, we find that the distributions tails exhibit exponential decay. Our findings may inform the development of models of market behavior across varying time scales.

  4. Power Curve Measurements, quantify the production increase

    DEFF Research Database (Denmark)

    Gómez Arranz, Paula; Vesth, Allan

    The purpose of this report is to quantify the production increase on a given turbine with respect to another given turbine. The used methodology is the “side by side” comparison method, provided by the client. This method involves the use of two neighboring turbines and it is based on the assumpt......The purpose of this report is to quantify the production increase on a given turbine with respect to another given turbine. The used methodology is the “side by side” comparison method, provided by the client. This method involves the use of two neighboring turbines and it is based...... on the assumption that the wind field in front of the tested turbines is statistically the same (i.e. has in average the same mean wind speed conditions in front of both turbines). The method is only used for the evaluation of a relative change in the AEP, not the AEP itself....

  5. Quantifying the robustness of metro networks

    CERN Document Server

    Wang, Xiangrong; Derrible, Sybil; Ahmad, Sk Nasir; Kooij, Robert E

    2015-01-01

    Metros (heavy rail transit systems) are integral parts of urban transportation systems. Failures in their operations can have serious impacts on urban mobility, and measuring their robustness is therefore critical. Moreover, as physical networks, metros can be viewed as network topological entities, and as such they possess measurable network properties. In this paper, by using network science and graph theoretical concepts, we investigate both theoretical and experimental robustness metrics (i.e., the robustness indicator, the effective graph conductance, and the critical thresholds) and their performance in quantifying the robustness of metro networks under random failures or targeted attacks. We find that the theoretical metrics quantify different aspects of the robustness of metro networks. In particular, the robustness indicator captures the number of alternative paths and the effective graph conductance focuses on the length of each path. Moreover, the high positive correlation between the theoretical m...

  6. Quantifying Shannon's Work Function for Cryptanalytic Attacks

    CERN Document Server

    van Son, R J J H

    2010-01-01

    Attacks on cryptographic systems are limited by the available computational resources. A theoretical understanding of these resource limitations is needed to evaluate the security of cryptographic primitives and procedures. This study uses an Attacker versus Environment game formalism based on computability logic to quantify Shannon's work function and evaluate resource use in cryptanalysis. A simple cost function is defined which allows to quantify a wide range of theoretical and real computational resources. With this approach the use of custom hardware, e.g., FPGA boards, in cryptanalysis can be analyzed. Applied to real cryptanalytic problems, it raises, for instance, the expectation that the computer time needed to break some simple 90 bit strong cryptographic primitives might theoretically be less than two years.

  7. Quantifying reliability uncertainty : a proof of concept.

    Energy Technology Data Exchange (ETDEWEB)

    Diegert, Kathleen V.; Dvorack, Michael A.; Ringland, James T.; Mundt, Michael Joseph; Huzurbazar, Aparna (Los Alamos National Laboratory, Los Alamos, NM); Lorio, John F.; Fatherley, Quinn (Los Alamos National Laboratory, Los Alamos, NM); Anderson-Cook, Christine (Los Alamos National Laboratory, Los Alamos, NM); Wilson, Alyson G. (Los Alamos National Laboratory, Los Alamos, NM); Zurn, Rena M.

    2009-10-01

    This paper develops Classical and Bayesian methods for quantifying the uncertainty in reliability for a system of mixed series and parallel components for which both go/no-go and variables data are available. Classical methods focus on uncertainty due to sampling error. Bayesian methods can explore both sampling error and other knowledge-based uncertainties. To date, the reliability community has focused on qualitative statements about uncertainty because there was no consensus on how to quantify them. This paper provides a proof of concept that workable, meaningful quantification methods can be constructed. In addition, the application of the methods demonstrated that the results from the two fundamentally different approaches can be quite comparable. In both approaches, results are sensitive to the details of how one handles components for which no failures have been seen in relatively few tests.

  8. Tracing Planets in Circumstellar Discs

    Directory of Open Access Journals (Sweden)

    Uribe Ana L.

    2013-04-01

    Full Text Available Planets are assumed to form in circumstellar discs around young stellar objects. The additional gravitational potential of a planet perturbs the disc and leads to characteristic structures, i.e. spiral waves and gaps, in the disc density profile. We perform a large-scale parameter study on the observability of these planet-induced structures in circumstellar discs in the (submm wavelength range for the Atacama Large (SubMillimeter Array (ALMA. On the basis of hydrodynamical and magneto-hydrodynamical simulations of star-disc-planet models we calculate the disc temperature structure and (submm images of these systems. These are used to derive simulated ALMA maps. Because appropriate objects are frequent in the Taurus-Auriga region, we focus on a distance of 140 pc and a declination of ≈ 20°. The explored range of star-disc-planet configurations consists of six hydrodynamical simulations (including magnetic fields and different planet masses, nine disc sizes with outer radii ranging from 9 AU to 225 AU, 15 total disc masses in the range between 2.67·10-7 M⊙ and 4.10·10-2 M⊙, six different central stars and two different grain size distributions, resulting in 10 000 disc models. At almost all scales and in particular down to a scale of a few AU, ALMA is able to trace disc structures induced by planet-disc interaction or the influence of magnetic fields in the wavelength range between 0.4...2.0 mm. In most cases, the optimum angular resolution is limited by the sensitivity of ALMA. However, within the range of typical masses of protoplane tary discs (0.1 M⊙...0.001 M⊙ the disc mass has a minor impact on the observability. At the distance of 140 pc it is possible to resolve discs down to 2.67·10-6 M⊙ and trace gaps in discs with 2.67·10-4 M⊙ with a signal-to-noise ratio greater than three. In general, it is more likely to trace planet-induced gaps in magneto-hydrodynamical disc models, because gaps are wider in the presence of

  9. Quantifying sediment production in steepland environments

    OpenAIRE

    2009-01-01

    Five published contributions to our understanding of the impacts of erosion processes on sustainable land management are reviewed and discussed. These focus on rapid shallow landsliding and gully erosion which are among the most prevalent forms of environmental degradation in New Zealand's hill country. The over-arching goal of this research has been to quantify the on-site (e.g., soil erosion, land productivity) impacts of these processes. Rather than measure erosion rates over long periods ...

  10. RAY TRACING IMPLEMENTATION IN JAVA PROGRAMMING LANGUAGE

    Directory of Open Access Journals (Sweden)

    Aybars UĞUR

    2002-01-01

    Full Text Available In this paper realism in computer graphics and components providing realism are discussed at first. It is mentioned about illumination models, surface rendering methods and light sources for this aim. After that, ray tracing which is a technique for creating two dimensional image of a three-dimensional virtual environment is explained briefly. A simple ray tracing algorithm was given. "SahneIzle" which is a ray tracing program implemented in Java programming language which can be used on the internet is introduced. As a result, importance of network-centric ray tracing software is discussed.

  11. Interpretation of complexometric titration data: An intercomparison of methods for estimating models of trace metal complexation by natural organic ligands

    NARCIS (Netherlands)

    Pižeta, I.; Sander, S.G.; Hudson, R.J.M.; Omanovic, D.; Baars, O.; Barbeau, K.A.; Buck, K.N.; Bundy, R.M.; Carrasco, G.; Croot, P.L.; Garnier, C.; Gerringa, L.J.A.; Gledhill, M.; Hirose, K.; Kondo, Y.; Laglera, L.M.; Nuester, J.; Rijkenberg, M.J.A.; Takeda, S.; Twining, B.S.; Wells, M.

    2015-01-01

    With the common goal of more accurately and consistently quantifying ambient concentrations of free metal ions and natural organic ligands in aquatic ecosystems, researchers from 15 laboratories that routinely analyze trace metal speciation participated in an intercomparison of statistical methods u

  12. Experimental study of trace element partitioning between lunar orthopyroxene and anhydrous silicate melt: Effects of lithium and iron

    NARCIS (Netherlands)

    Kan Parker, M. van; Mason, P.R.D.; Westrenen, W. van

    2011-01-01

    Orthopyroxene (Opx) was present during a significant portion of crystallisation of the lunar magma ocean, but its influence on co-existing melt trace element contents is not well quantified. We performed highpressure (P, 1.1 to 3.2 GPa), high-temperature (T, 1400 to 1600 °C) experiments on synthetic

  13. Method development for liquid chromatographic/triple quadrupole mass spectrometric analysis of trace level perfluorocarboxylic acids in articles of commerce

    Science.gov (United States)

    An analytical method to identify and quantify trace levels of C5 to C12 perfluorocarboxylic acids (PFCAs) in articles of commerce (AOC) is developed and rigorously validated. Solid samples were extracted in methanol, and liquid samples were diluted with a solvent consisting of 60...

  14. Interpretation of complexometric titration data: An intercomparison of methods for estimating models of trace metal complexation by natural organic ligands

    NARCIS (Netherlands)

    Pižeta, I.; Sander, S.G.; Hudson, R.J.M.; Omanovic, D.; Baars, O.; Barbeau, K.A.; Buck, K.N.; Bundy, R.M.; Carrasco, G.; Croot, P.L.; Garnier, C.; Gerringa, L.J.A.; Gledhill, M.; Hirose, K.; Kondo, Y.; Laglera, L.M.; Nuester, J.; Rijkenberg, M.J.A.; Takeda, S.; Twining, B.S.; Wells, M.

    2015-01-01

    With the common goal of more accurately and consistently quantifying ambient concentrations of free metal ions and natural organic ligands in aquatic ecosystems, researchers from 15 laboratories that routinely analyze trace metal speciation participated in an intercomparison of statistical methods u

  15. Accelerating optimization by tracing valley

    Science.gov (United States)

    Li, Qing-Xiao; He, Rong-Qiang; Lu, Zhong-Yi

    2016-06-01

    We propose an algorithm to accelerate optimization when an objective function locally resembles a long narrow valley. In such a case, a conventional optimization algorithm usually wanders with too many tiny steps in the valley. The new algorithm approximates the valley bottom locally by a parabola that is obtained by fitting a set of successive points generated recently by a conventional optimization method. Then large steps are taken along the parabola, accompanied by fine adjustment to trace the valley bottom. The effectiveness of the new algorithm has been demonstrated by accelerating the Newton trust-region minimization method and the Levenberg-Marquardt method on the nonlinear fitting problem in exact diagonalization dynamical mean-field theory and on the classic minimization problem of the Rosenbrock's function. Many times speedup has been achieved for both problems, showing the high efficiency of the new algorithm.

  16. 13 CFR 120.348 - Amount of guarantee.

    Science.gov (United States)

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Amount of guarantee. 120.348 Section 120.348 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION BUSINESS LOANS Special Purpose Loans International Trade Loans § 120.348 Amount of guarantee. SBA can guarantee up to...

  17. 5 CFR 870.1003 - Coverage and amount of insurance.

    Science.gov (United States)

    2010-01-01

    ... REGULATIONS (CONTINUED) FEDERAL EMPLOYEES' GROUP LIFE INSURANCE PROGRAM Benefits for United States Hostages in... of Basic life insurance for these individuals is the amount specified in § 870.202, subject to the... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Coverage and amount of insurance....

  18. 5 CFR 870.1102 - Amount of a Living Benefit.

    Science.gov (United States)

    2010-01-01

    ... REGULATIONS (CONTINUED) FEDERAL EMPLOYEES' GROUP LIFE INSURANCE PROGRAM Living Benefits § 870.1102 Amount of a... of his/her Basic insurance, or (ii) A partial Living Benefit, which is a portion of his/her Basic... Living Benefit. (b) The amount of Basic insurance elected as a Living Benefit will be reduced by...

  19. 75 FR 58285 - Short-Term, Small Amount Loans

    Science.gov (United States)

    2010-09-24

    ... Part 701 RIN 3133-AD71 Short-Term, Small Amount Loans Agency: National Credit Union Administration... unions (FCUs) to offer short-term, small amount loans (STS loans) as a viable alternative to predatory payday loans. The amendment permits FCUs to charge a higher interest rate for an STS loan than is...

  20. 26 CFR 1.666(a)-1A - Amount allocated.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 8 2010-04-01 2010-04-01 false Amount allocated. 1.666(a)-1A Section 1.666(a... Before January 1, 1969 § 1.666(a)-1A Amount allocated. (a) In general. In the case of a trust that is... that may accumulate income or that distribute corpus), section 666(a) prescribes rules for...

  1. 26 CFR 1.666(a)-1 - Amount allocated.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 8 2010-04-01 2010-04-01 false Amount allocated. 1.666(a)-1 Section 1.666(a)-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED... January 1, 1969 § 1.666(a)-1 Amount allocated. (a)(1) If a trust other than a foreign trust created by a...

  2. 26 CFR 1.662(a)-3 - Other amounts distributed.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 8 2010-04-01 2010-04-01 false Other amounts distributed. 1.662(a)-3 Section 1.662(a)-3 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES Estates and Trusts Which May Accumulate Income Or Which Distribute Corpus § 1.662(a)-3 Other amounts distributed. (a)...

  3. 42 CFR 409.102 - Amounts of payment.

    Science.gov (United States)

    2010-10-01

    ... HOSPITAL INSURANCE BENEFITS Payment of Hospital Insurance Benefits § 409.102 Amounts of payment. (a) The amounts Medicare pays for hospital insurance benefits are generally determined in accordance with part 412 or part 413 of this chapter. (b) Except as provided in §§ 409.61(d) and 409.89, hospital insurance...

  4. 20 CFR 404.333 - Wife's and husband's benefit amounts.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Wife's and husband's benefit amounts. 404.333... Disability Benefits for Spouses and Divorced Spouses § 404.333 Wife's and husband's benefit amounts. Your wife's or husband's monthly benefit is equal to one-half the insured person's primary insurance...

  5. 27 CFR 40.133 - Amount of individual bond.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 2 2010-04-01 2010-04-01 false Amount of individual bond. 40.133 Section 40.133 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU..., AND PROCESSED TOBACCO Bonds and Extensions of Coverage of Bonds § 40.133 Amount of individual...

  6. 20 CFR 362.12 - Computation of amount of reimbursement.

    Science.gov (United States)

    2010-04-01

    ... the cost of repair is the amount payable. (b) Depreciation in value of an item of personal property is... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Computation of amount of reimbursement. 362.12 Section 362.12 Employees' Benefits RAILROAD RETIREMENT BOARD INTERNAL ADMINISTRATION, POLICY AND...

  7. 46 CFR 151.45-6 - Maximum amount of cargo.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Maximum amount of cargo. 151.45-6 Section 151.45-6 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES BARGES CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Operations § 151.45-6 Maximum amount of cargo. (a)...

  8. 29 CFR 530.302 - Amounts of civil money penalties.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Amounts of civil money penalties. 530.302 Section 530.302... EMPLOYMENT OF HOMEWORKERS IN CERTAIN INDUSTRIES Civil Money Penalties § 530.302 Amounts of civil money penalties. (a) A civil money penalty, not to exceed $500 per affected homeworker for any one violation, may...

  9. 5 CFR 841.503 - Amounts of employee deductions.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Amounts of employee deductions. 841.503 Section 841.503 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT (CONTINUED) CIVIL SERVICE... deductions have ceased because of the amount of earnings during the year, or are not made for any...

  10. 41 CFR 105-56.019 - Offset amount.

    Science.gov (United States)

    2010-07-01

    ... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Offset amount. 105-56... Administration 56-SALARY OFFSET FOR INDEBTEDNESS OF FEDERAL EMPLOYEES TO THE UNITED STATES Centralized Salary Offset (CSO) Procedures-GSA as Creditor Agency § 105-56.019 Offset amount. (a) The minimum dollar...

  11. Minimum Amount of Slop Cut in Batch Distillation

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The pulse-control operation technique which alternates between total reflux operation and total efflux operation in batch distillation was studied along with the minimum amount of slop cut.Total reflux time was confirmed by dynamic simulation, and total efflux time was adopted by statistic method. For the mixture of hexane and cyclohexane and the traditional constant reflux ratio operation strategy, the amount of slop cut is 1.8-2.1 times of the minimum amount of slop cut; whereas for the pulse-control operation strategy, it is 1.2-1.4 times of the minimum amount of slop cut. So compared with the traditional constant reflux ratio operation, the pulse-control operation can decrease the amount of slop cut and operation time, and meanwhile, enhance separation efficiency and yield.

  12. Method for determination of small amounts of rare earths and thorium in phosphate rocks

    Science.gov (United States)

    Waring, C.L.; Mela, H.

    1953-01-01

    In laboratory investigations, interest developed in the possible rare-earth content of phosphate samples from Florida and the northwestern United States. Because of the difficulty of making chemical determinations of traces of individual rare earths, a combined chemical-spectrographic method was investigated. After removal of iron by the extraction of the chloride with ether, the rare earths and thorium are concentrated by double oxalate precipitation, using calcium as a carrier. The rare earths are freed from calcium by an ammonium hydroxide precipitation with a fixed amount of aluminum as a carrier. The aluminum also serves as an internal standard in the final spectrographic analysis. The method will determine from 0.02 to 2 mg. of each rare earth with an error no greater than 10%. The investigation has resulted in a fairly rapid and precise procedure, involving no special spectrographic setup. The method could be applied to other types of geologic materials with the same expected accuracy.

  13. Gains and Pitfalls of Quantifier Elimination as a Teaching Tool

    Science.gov (United States)

    Oldenburg, Reinhard

    2015-01-01

    Quantifier Elimination is a procedure that allows simplification of logical formulas that contain quantifiers. Many mathematical concepts are defined in terms of quantifiers and especially in calculus their use has been identified as an obstacle in the learning process. The automatic deduction provided by quantifier elimination thus allows…

  14. Issues in the study of floating universal numeric quantifiers

    NARCIS (Netherlands)

    R. Cirillo

    2010-01-01

    In the Germanic and Romance languages (among others) a universal quantifier can combine with a numeral and form a floating quantifier. I refer to these quantifiers as universal numeric quantifiers or simply ∀NumQ. The following examples from Dutch and Romanian demonstrate this phenomenon: The aim of

  15. Fuel characteristics and trace gases produced through biomass burning

    Directory of Open Access Journals (Sweden)

    BAMBANG HERO SAHARJO

    2010-01-01

    Full Text Available Saharjo BH, Sudo S, Yonemura S, Tsuruta H (2010 Fuel characteristics and trace gases produced through biomass burning. Biodiversitas 11: 40-45. Indonesian 1997/1998 forest fires resulted in forest destruction totally 10 million ha with cost damaged about US$ 10 billion, where more than 1 Gt CO2 has been released during the fire episode and elevating Indonesia to one of the largest polluters of carbon in the world where 22% of world’s carbon dioxide produced. It has been found that 80-90% of the fire comes from estate crops and industrial forest plantation area belongs to the companies which using fire illegally for the land preparation. Because using fire is cheap, easy and quick and also support the companies purpose in achieving yearly planted area target. Forest management and land use practices in Sumatra and Kalimantan have evolved very rapidly over the past three decades. Poor logging practices resulted in large amounts of waste will left in the forest, greatly elevating fire hazard. Failure by the government and concessionaires to protect logged forests and close old logging roads led to and invasion of the forest by agricultural settlers whose land clearances practices increased the risk of fire. Several field experiments had been done in order to know the quality and the quantity of trace produced during biomass burning in peat grass, peat soil and alang-alang grassland located in South Sumatra, Indonesia. Result of research show that different characteristics of fuel burned will have the different level also in trace gasses produced. Peat grass with higher fuel load burned produce more trace gasses compared to alang-alang grassland and peat soil.

  16. [Determination of trace elements in Mongolian medicine Susi-12 curing cholecystitis and gallstone disease by ICP-AES].

    Science.gov (United States)

    E, Er-Deng-sang; Hang, Gai-ba-te-re; Ba, Tu; Duan, Yi-wen

    2009-04-01

    Trace elements in Mongolian medicine Susi-12 for cholecystitis and gallstones were analyzed in order to discuss the relation between Susi-12's drug action and the trace elements. The analysis was carried out using the pressure seal microwave digestion and inductive coupled plasma atomic emission spectrometry (ICP-AES). It was found that the medicine contained great amount of trace elements, especially human-body-needed trace elements, such as Ca, Al, Mg, Fe, Sr, Mn, Zn, Cu etc., whereas heavy metals are very little, e.g. the contents of Pb, Cb, As etc are below the country's limit. The recoveries of standard addition are in the range of 94.63%-106.40%. The relative standard deviation RSDSusi-12 can effectively control and cure cholecystitis and gallstones, and the effective rate reaches 91.2% to 100%. So the trace elements in Susi-12 must have a close connection with the drug action.

  17. MAPPING THE GALACTIC HALO. VIII. QUANTIFYING SUBSTRUCTURE

    NARCIS (Netherlands)

    Starkenburg, Else; Helmi, Amina; Morrison, Heather L.; Harding, Paul; van Woerden, Hugo; Mateo, Mario; Olszewski, Edward W.; Sivarani, Thirupathi; Norris, John E.; Freeman, Kenneth C.; Shectman, Stephen A.; Dohm-Palmer, R. C.; Frey, Lucy; Oravetz, Dan

    2009-01-01

    We have measured the amount of kinematic substructure in the Galactic halo using the final data set from the Spaghetti project, a pencil-beam high-latitude sky survey. Our sample contains 101 photometrically selected and spectroscopically confirmed giants with accurate distance, radial velocity, and

  18. Validation of Ray Tracing Code Refraction Effects

    Science.gov (United States)

    Heath, Stephanie L.; McAninch, Gerry L.; Smith, Charles D.; Conner, David A.

    2008-01-01

    NASA's current predictive capabilities using the ray tracing program (RTP) are validated using helicopter noise data taken at Eglin Air Force Base in 2007. By including refractive propagation effects due to wind and temperature, the ray tracing code is able to explain large variations in the data observed during the flight test.

  19. A new PICL trace file format

    Energy Technology Data Exchange (ETDEWEB)

    Worley, P.H.

    1992-10-01

    A trace file format is described that will be used in future releases of the Portable Instrumented Communication Library (PICL) and ParaGraph. The new format provides improved support for tracing and profiling PICL communication primitives and user-defined events. The new format is also easily extended and may be useful in other instrumentation packages and performance visualization tools.

  20. Process tracing methods: foundation and guidelines

    DEFF Research Database (Denmark)

    Beach, Derek; Pedersen, Rasmus Brun

    Derek Beach and Rasmus Brun Pedersen have written the first practical guide for using process tracing in social science research. The book introduces a more refined definition of what process tracing methods are, differentiating it into three variants, showing the uses and limitations of each. Th...

  1. Analytical Methods for Trace Metals. Training Manual.

    Science.gov (United States)

    Office of Water Program Operations (EPA), Cincinnati, OH. National Training and Operational Technology Center.

    This training manual presents material on the theoretical concepts involved in the methods listed in the Federal Register as approved for determination of trace metals. Emphasis is on laboratory operations. This course is intended for chemists and technicians with little or no experience in analytical methods for trace metals. Students should have…

  2. NSF-RANN trace contaminants abstracts

    Energy Technology Data Exchange (ETDEWEB)

    Copenhaver, E.D.; Harnden, D.S. (eds.)

    1976-10-01

    Specific areas of interest of the Environmental Aspects of Trace Contaminants Program are organic chemicals of commerce, metals and organometallic compounds, air-borne contaminants, and environmental assay methodology. Fifty-three abstracts of literature on trace contaminants are presented. Author, keyword, and permuted title indexes are included. (HLW)

  3. Entities of interest : Discovery in digital traces

    NARCIS (Netherlands)

    Graus, D.P.

    2017-01-01

    In the era of big data, we continuously — and at times unknowingly — leave behind digital traces, by browsing, sharing, posting, liking, searching, watching, and listening to online content. Aggregated, these digital traces can provide powerful insights into the behavior, preferences, activities, an

  4. Trace Elements in Ovaries: Measurement and Physiology.

    Science.gov (United States)

    Ceko, Melanie J; O'Leary, Sean; Harris, Hugh H; Hummitzsch, Katja; Rodgers, Raymond J

    2016-04-01

    Traditionally, research in the field of trace element biology and human and animal health has largely depended on epidemiological methods to demonstrate involvement in biological processes. These studies were typically followed by trace element supplementation trials or attempts at identification of the biochemical pathways involved. With the discovery of biological molecules that contain the trace elements, such as matrix metalloproteinases containing zinc (Zn), cytochrome P450 enzymes containing iron (Fe), and selenoproteins containing selenium (Se), much of the current research focuses on these molecules, and, hence, only indirectly on trace elements themselves. This review focuses largely on two synchrotron-based x-ray techniques: X-ray absorption spectroscopy and x-ray fluorescence imaging that can be used to identify the in situ speciation and distribution of trace elements in tissues, using our recent studies of bovine ovaries, where the distribution of Fe, Se, Zn, and bromine were determined. It also discusses the value of other techniques, such as inductively coupled plasma mass spectrometry, used to garner information about the concentrations and elemental state of the trace elements. These applications to measure trace elemental distributions in bovine ovaries at high resolutions provide new insights into possible roles for trace elements in the ovary.

  5. Reverse ray tracing for transformation optics.

    Science.gov (United States)

    Hu, Chia-Yu; Lin, Chun-Hung

    2015-06-29

    Ray tracing is an important technique for predicting optical system performance. In the field of transformation optics, the Hamiltonian equations of motion for ray tracing are well known. The numerical solutions to the Hamiltonian equations of motion are affected by the complexities of the inhomogeneous and anisotropic indices of the optical device. Based on our knowledge, no previous work has been conducted on ray tracing for transformation optics with extreme inhomogeneity and anisotropicity. In this study, we present the use of 3D reverse ray tracing in transformation optics. The reverse ray tracing is derived from Fermat's principle based on a sweeping method instead of finding the full solution to ordinary differential equations. The sweeping method is employed to obtain the eikonal function. The wave vectors are then obtained from the gradient of that eikonal function map in the transformed space to acquire the illuminance. Because only the rays in the points of interest have to be traced, the reverse ray tracing provides an efficient approach to investigate the illuminance of a system. This approach is useful in any form of transformation optics where the material property tensor is a symmetric positive definite matrix. The performance and analysis of three transformation optics with inhomogeneous and anisotropic indices are explored. The ray trajectories and illuminances in these demonstration cases are successfully solved by the proposed reverse ray tracing method.

  6. Trace elements in animal production systems

    NARCIS (Netherlands)

    Schlegel, P.; Durosoy, S.; Jongbloed, A.W.

    2008-01-01

    This book deals with trace elements, such as cobalt, copper, iron, manganese, selenium and zinc which are essential to modern animal nutrition, but are increasingly detrimental to soil and water quality in today's globalized production. The goal in finding a sustainable balance between trace element

  7. (Second) Quantised resolvents and regularised traces

    Science.gov (United States)

    Paycha, Sylvie

    2007-04-01

    Regularised traces on classical pseudodifferential operators are extended to tensor products of classical pseudodifferential operators via a (second) quantisation procedure. Whereas ordinary ζ-regularised traces are not generally expected to be local, using techniques borrowed from Connes and Moscovici [A. Connes, H. Moscovici, The local index formula in noncommutative geometry, Geom. Funct. Anal. 5 (2) (1995) 174-243], Higson [N. Higson, The residue index theorem of Connes and Moscovici, in: Clay Mathematics Proceedings, 2004, http://www.math.psu.edu/higson/ResearchPapers.html], we show that if Q has scalar leading symbol, higher quantisedζ- regularised traces are local since they can be expressed as a finite linear combination of noncommutative residues. Just as ordinary ζ-regularised traces, they present anomalies (Hochschild coboundary, dependence on the weight Q), which for quantised ζ-regularised traces of level n, are roughly speaking finite linear combinations of quantised regularised traces of level n+1. As a result, anomalies are local for any non negative n, which yields back as a particular case the fact that ordinary ζ-regularised traces present local anomalies. This work is partially based on [S. Paycha, Weighted trace cochains; A geometric setup for anomalies, Max Planck Institute, 2005. Preprint] although we use other conventions here which lead to slightly different definitions.

  8. Quantifier spreading: children misled by ostensive cues

    Directory of Open Access Journals (Sweden)

    Katalin É. Kiss

    2017-04-01

    Full Text Available This paper calls attention to a methodological problem of acquisition experiments. It shows that the economy of the stimulus employed in child language experiments may lend an increased ostensive effect to the message communicated to the child. Thus, when the visual stimulus in a sentence-picture matching task is a minimal model abstracting away from the details of the situation, children often regard all the elements of the stimulus as ostensive clues to be represented in the corresponding sentence. The use of such minimal stimuli is mistaken when the experiment aims to test whether or not a certain element of the stimulus is relevant for the linguistic representation or interpretation. The paper illustrates this point by an experiment involving quantifier spreading. It is claimed that children find a universally quantified sentence like 'Every girl is riding a bicycle 'to be a false description of a picture showing three girls riding bicycles and a solo bicycle because they are misled to believe that all the elements in the visual stimulus are relevant, hence all of them are to be represented by the corresponding linguistic description. When the iconic drawings were replaced by photos taken in a natural environment rich in accidental details, the occurrence of quantifier spreading was radically reduced. It is shown that an extra object in the visual stimulus can lead to the rejection of the sentence also in the case of sentences involving no quantification, which gives further support to the claim that the source of the problem is not (or not only the grammatical or cognitive difficulty of quantification but the unintended ostensive effect of the extra object.  This article is part of the special collection: Acquisition of Quantification

  9. Quantifying graininess of glossy food products

    DEFF Research Database (Denmark)

    Møller, Flemming; Carstensen, Jens Michael

    The sensory quality of yoghurt can be altered when changing the milk composition or processing conditions. Part of the sensory quality may be assessed visually. It is described how a non-contact method for quantifying surface gloss and grains in yoghurt can be made. It was found that the standard...... deviation of the entire image evaluated at different scales in a Gaussian Image Pyramid was a measure for graininess of yoghurt. This methodology is used to predict graininess (or grittiness) and to evaluate effect of yoghurt composition and processing....

  10. Quantifying information leakage of randomized protocols

    DEFF Research Database (Denmark)

    Biondi, Fabrizio; Legay, Axel; Malacaria, Pasquale;

    2015-01-01

    capable to observe the internal behavior of the system, and quantify the information leakage of such systems. We also use our method to obtain an algorithm for the computation of channel capacity from our Markovian models. Finally, we show how to use the method to analyze timed and non-timed attacks......The quantification of information leakage provides a quantitative evaluation of the security of a system. We propose the usage of Markovian processes to model deterministic and probabilistic systems. By using a methodology generalizing the lattice of information approach we model refined attackers...

  11. Quantifying Heuristic Bias: Anchoring, Availability, and Representativeness.

    Science.gov (United States)

    Richie, Megan; Josephson, S Andrew

    2017-07-28

    Construct: Authors examined whether a new vignette-based instrument could isolate and quantify heuristic bias. Heuristics are cognitive shortcuts that may introduce bias and contribute to error. There is no standardized instrument available to quantify heuristic bias in clinical decision making, limiting future study of educational interventions designed to improve calibration of medical decisions. This study presents validity data to support a vignette-based instrument quantifying bias due to the anchoring, availability, and representativeness heuristics. Participants completed questionnaires requiring assignment of probabilities to potential outcomes of medical and nonmedical scenarios. The instrument randomly presented scenarios in one of two versions: Version A, encouraging heuristic bias, and Version B, worded neutrally. The primary outcome was the difference in probability judgments for Version A versus Version B scenario options. Of 167 participants recruited, 139 enrolled. Participants assigned significantly higher mean probability values to Version A scenario options (M = 9.56, SD = 3.75) than Version B (M = 8.98, SD = 3.76), t(1801) = 3.27, p = .001. This result remained significant analyzing medical scenarios alone (Version A, M = 9.41, SD = 3.92; Version B, M = 8.86, SD = 4.09), t(1204) = 2.36, p = .02. Analyzing medical scenarios by heuristic revealed a significant difference between Version A and B for availability (Version A, M = 6.52, SD = 3.32; Version B, M = 5.52, SD = 3.05), t(404) = 3.04, p = .003, and representativeness (Version A, M = 11.45, SD = 3.12; Version B, M = 10.67, SD = 3.71), t(396) = 2.28, p = .02, but not anchoring. Stratifying by training level, students maintained a significant difference between Version A and B medical scenarios (Version A, M = 9.83, SD = 3.75; Version B, M = 9.00, SD = 3.98), t(465) = 2.29, p = .02, but not residents or attendings. Stratifying by heuristic and training level, availability maintained

  12. Quantifying information leakage of randomized protocols

    DEFF Research Database (Denmark)

    Biondi, Fabrizio; Legay, Axel; Malacaria, Pasquale

    2015-01-01

    The quantification of information leakage provides a quantitative evaluation of the security of a system. We propose the usage of Markovian processes to model deterministic and probabilistic systems. By using a methodology generalizing the lattice of information approach we model refined attackers...... capable to observe the internal behavior of the system, and quantify the information leakage of such systems. We also use our method to obtain an algorithm for the computation of channel capacity from our Markovian models. Finally, we show how to use the method to analyze timed and non-timed attacks...

  13. Scenario Based Worm Trace Pattern Identification Technique

    CERN Document Server

    Rahayu, S Siti; Shahrin, S; Zaki, Mohd M; Irda, R; Faizal, M A

    2010-01-01

    The number of malware variants is growing tremendously and the study of malware attacks on the Internet is still a demanding research domain. In this research, various logs from different OSI layer are explore to identify the traces leave on the attacker and victim logs, and the attack worm trace pattern are establish in order to reveal true attacker or victim. For the purpose of this paper, it will only concentrate on cybercrime that caused by malware network intrusion and used the traditional worm namely blaster worm variants. This research creates the concept of trace pattern by fusing the attackers and victims perspective. Therefore, the objective of this paper is to propose on attackers, victims and multistep, attacker or victim, trace patterns by combining both perspectives. These three proposed worm trace patterns can be extended into research areas in alert correlation and computer forensic investigation.

  14. Autonomous Real Time Requirements Tracing

    Science.gov (United States)

    Plattsmier, George; Stetson, Howard

    2014-01-01

    One of the more challenging aspects of software development is the ability to verify and validate the functional software requirements dictated by the Software Requirements Specification (SRS) and the Software Detail Design (SDD). Insuring the software has achieved the intended requirements is the responsibility of the Software Quality team and the Software Test team. The utilization of Timeliner-TLX(sup TM) Auto- Procedures for relocating ground operations positions to ISS automated on-board operations has begun the transition that would be required for manned deep space missions with minimal crew requirements. This transition also moves the auto-procedures from the procedure realm into the flight software arena and as such the operational requirements and testing will be more structured and rigorous. The autoprocedures would be required to meet NASA software standards as specified in the Software Safety Standard (NASASTD- 8719), the Software Engineering Requirements (NPR 7150), the Software Assurance Standard (NASA-STD-8739) and also the Human Rating Requirements (NPR-8705). The Autonomous Fluid Transfer System (AFTS) test-bed utilizes the Timeliner-TLX(sup TM) Language for development of autonomous command and control software. The Timeliner-TLX(sup TM) system has the unique feature of providing the current line of the statement in execution during real-time execution of the software. The feature of execution line number internal reporting unlocks the capability of monitoring the execution autonomously by use of a companion Timeliner-TLX(sup TM) sequence as the line number reporting is embedded inside the Timeliner-TLX(sup TM) execution engine. This negates I/O processing of this type data as the line number status of executing sequences is built-in as a function reference. This paper will outline the design and capabilities of the AFTS Autonomous Requirements Tracker, which traces and logs SRS requirements as they are being met during real-time execution of the

  15. Quantifying human response capabilities towards tsunami threats at community level

    Science.gov (United States)

    Post, J.; Mück, M.; Zosseder, K.; Wegscheider, S.; Taubenböck, H.; Strunz, G.; Muhari, A.; Anwar, H. Z.; Birkmann, J.; Gebert, N.

    2009-04-01

    besides others play a role. An attempt to quantify this variable under high uncertainty is also presented. Quantifying ET is based on a GIS modelling using a Cost Weighted Distance approach. Basic principle is to define the best evacuation path from a given point to the next safe area (shelter location). Here the fastest path from that point to the shelter location has to be found. Thereby the impact of land cover, slope, population density, population age and gender distribution are taken into account as literature studies prove these factors as highly important. Knowing the fastest path and the distance to the next safe area together with a spatially distributed pattern of evacuation speed delivers the time needed from each location to a safe area. By considering now the obtained time value for RsT the coverage area of an evacuation target point (safe area) can be assigned. Incorporating knowledge on people capacity of an evacuation target point the respective coverage area is refined. Hence areas with weak, moderate and good human response capabilities can be detected. This allows calculation of potential amount of people affected (dead or injured) and amount of people dislocated. First results for Kuta (Bali) for a worst case tsunami event deliver people affected of approx. 25 000 when RT = 0 minutes (direct evacuation when receiving a tsunami warning to 120 000 when RT > ETA (no evacuation action until tsunami hits the land). Additionally fastest evacuation routes to the evacuation target points can be assigned. Areas with weak response capabilities can be assigned as priority areas to install e.g. additional evacuation target points or to increase tsunami knowledge and awareness to promote a faster reaction time. Especially in analyzing underlying socio-economic properties causing deficiencies in responding to a tsunami threat can lead to valuable information and direct planning of adaptation measures. Keywords: Community level, Risk and vulnerability assessment

  16. Random pure states: Quantifying bipartite entanglement beyond the linear statistics.

    Science.gov (United States)

    Vivo, Pierpaolo; Pato, Mauricio P; Oshanin, Gleb

    2016-05-01

    We analyze the properties of entangled random pure states of a quantum system partitioned into two smaller subsystems of dimensions N and M. Framing the problem in terms of random matrices with a fixed-trace constraint, we establish, for arbitrary N≤M, a general relation between the n-point densities and the cross moments of the eigenvalues of the reduced density matrix, i.e., the so-called Schmidt eigenvalues, and the analogous functionals of the eigenvalues of the Wishart-Laguerre ensemble of the random matrix theory. This allows us to derive explicit expressions for two-level densities, and also an exact expression for the variance of von Neumann entropy at finite N,M. Then, we focus on the moments E{K^{a}} of the Schmidt number K, the reciprocal of the purity. This is a random variable supported on [1,N], which quantifies the number of degrees of freedom effectively contributing to the entanglement. We derive a wealth of analytical results for E{K^{a}} for N=2 and 3 and arbitrary M, and also for square N=M systems by spotting for the latter a connection with the probability P(x_{min}^{GUE}≥sqrt[2N]ξ) that the smallest eigenvalue x_{min}^{GUE} of an N×N matrix belonging to the Gaussian unitary ensemble is larger than sqrt[2N]ξ. As a by-product, we present an exact asymptotic expansion for P(x_{min}^{GUE}≥sqrt[2N]ξ) for finite N as ξ→∞. Our results are corroborated by numerical simulations whenever possible, with excellent agreement.

  17. Quantifying Poverty as a Driver of Ebola Transmission

    Science.gov (United States)

    Gertler, Shai; Yamin, Dan; Galvani, Alison P.

    2015-01-01

    Background Poverty has been implicated as a challenge in the control of the current Ebola outbreak in West Africa. Although disparities between affected countries have been appreciated, disparities within West African countries have not been investigated as drivers of Ebola transmission. To quantify the role that poverty plays in the transmission of Ebola, we analyzed heterogeneity of Ebola incidence and transmission factors among over 300 communities, categorized by socioeconomic status (SES), within Montserrado County, Liberia. Methodology/Principal Findings We evaluated 4,437 Ebola cases reported between February 28, 2014 and December 1, 2014 for Montserrado County to determine SES-stratified temporal trends and drivers of Ebola transmission. A dataset including dates of symptom onset, hospitalization, and death, and specified community of residence was used to stratify cases into high, middle and low SES. Additionally, information about 9,129 contacts was provided for a subset of 1,585 traced individuals. To evaluate transmission within and across socioeconomic subpopulations, as well as over the trajectory of the outbreak, we analyzed these data with a time-dependent stochastic model. Cases in the most impoverished communities reported three more contacts on average than cases in high SES communities (p<0.001). Our transmission model shows that infected individuals from middle and low SES communities were associated with 1.5 (95% CI: 1.4–1.6) and 3.5 (95% CI: 3.1–3.9) times as many secondary cases as those from high SES communities, respectively. Furthermore, most of the spread of Ebola across Montserrado County originated from areas of lower SES. Conclusions/Significance Individuals from areas of poverty were associated with high rates of transmission and spread of Ebola to other regions. Thus, Ebola could most effectively be prevented or contained if disease interventions were targeted to areas of extreme poverty and funding was dedicated to development

  18. Random pure states: Quantifying bipartite entanglement beyond the linear statistics

    Science.gov (United States)

    Vivo, Pierpaolo; Pato, Mauricio P.; Oshanin, Gleb

    2016-05-01

    We analyze the properties of entangled random pure states of a quantum system partitioned into two smaller subsystems of dimensions N and M . Framing the problem in terms of random matrices with a fixed-trace constraint, we establish, for arbitrary N ≤M , a general relation between the n -point densities and the cross moments of the eigenvalues of the reduced density matrix, i.e., the so-called Schmidt eigenvalues, and the analogous functionals of the eigenvalues of the Wishart-Laguerre ensemble of the random matrix theory. This allows us to derive explicit expressions for two-level densities, and also an exact expression for the variance of von Neumann entropy at finite N ,M . Then, we focus on the moments E {Ka} of the Schmidt number K , the reciprocal of the purity. This is a random variable supported on [1 ,N ] , which quantifies the number of degrees of freedom effectively contributing to the entanglement. We derive a wealth of analytical results for E {Ka} for N =2 and 3 and arbitrary M , and also for square N =M systems by spotting for the latter a connection with the probability P (xminGUE≥√{2 N }ξ ) that the smallest eigenvalue xminGUE of an N ×N matrix belonging to the Gaussian unitary ensemble is larger than √{2 N }ξ . As a by-product, we present an exact asymptotic expansion for P (xminGUE≥√{2 N }ξ ) for finite N as ξ →∞ . Our results are corroborated by numerical simulations whenever possible, with excellent agreement.

  19. Quantifying Poverty as a Driver of Ebola Transmission.

    Directory of Open Access Journals (Sweden)

    Mosoka P Fallah

    2015-12-01

    Full Text Available Poverty has been implicated as a challenge in the control of the current Ebola outbreak in West Africa. Although disparities between affected countries have been appreciated, disparities within West African countries have not been investigated as drivers of Ebola transmission. To quantify the role that poverty plays in the transmission of Ebola, we analyzed heterogeneity of Ebola incidence and transmission factors among over 300 communities, categorized by socioeconomic status (SES, within Montserrado County, Liberia.We evaluated 4,437 Ebola cases reported between February 28, 2014 and December 1, 2014 for Montserrado County to determine SES-stratified temporal trends and drivers of Ebola transmission. A dataset including dates of symptom onset, hospitalization, and death, and specified community of residence was used to stratify cases into high, middle and low SES. Additionally, information about 9,129 contacts was provided for a subset of 1,585 traced individuals. To evaluate transmission within and across socioeconomic subpopulations, as well as over the trajectory of the outbreak, we analyzed these data with a time-dependent stochastic model. Cases in the most impoverished communities reported three more contacts on average than cases in high SES communities (p<0.001. Our transmission model shows that infected individuals from middle and low SES communities were associated with 1.5 (95% CI: 1.4-1.6 and 3.5 (95% CI: 3.1-3.9 times as many secondary cases as those from high SES communities, respectively. Furthermore, most of the spread of Ebola across Montserrado County originated from areas of lower SES.Individuals from areas of poverty were associated with high rates of transmission and spread of Ebola to other regions. Thus, Ebola could most effectively be prevented or contained if disease interventions were targeted to areas of extreme poverty and funding was dedicated to development projects that meet basic needs.

  20. Amount of Future Forest Interior at a 2 Hectare Scale

    Data.gov (United States)

    U.S. Environmental Protection Agency — Forests provide economic and ecological value. High amounts of forest interior indicates a highly connected forest, which generally enhances those economic and...

  1. Amount of Forest Edge at a 65 Hectare Scale

    Data.gov (United States)

    U.S. Environmental Protection Agency — Forests provide economic and ecological value. High amounts of forest edge indicates a highly fragmented forest, which generally diminishes those economic and...

  2. Amount of Forest Edge at a 2 Hectare Scale

    Data.gov (United States)

    U.S. Environmental Protection Agency — Forests provide economic and ecological value. High amounts of forest edge indicates a highly fragmented forest, which generally diminishes those economic and...

  3. Effect of Precipitable Water Vapor Amount on Radiative Cooling Performance

    Science.gov (United States)

    Hu, Mingke; Zhao, Bin; Ao, Xianze; Pei, Gang

    2017-05-01

    A radiative cooler based on aluminum-evaporated polyvinyl-fluoride surface was employed to investigate the effect of precipitable water vapor amount on its radiative cooling performance. A mathematic model of steady heat transfer that considers the spectral radiant distribution of the sky, the transparent cover and the collecting surface was established. The results indicate that the amount of precipitable water vapor shows a remarkable and negative effect on radiative cooling performance of the radiative cooler. Both the temperature difference between the cooler and surroundings and the net radiative cooling power decrease as the precipitable water vapor amount increases. The net radiative cooling power drops by about 41.0% as the the precipitable water vapor amount changes from 1.0 cm to 7.0 cm. Besides, the radiative cooler shows better cooling performance in winter than in summer. The net radiative cooling power in summer of Hefei is about 82.2% of that in winter.

  4. USING OF THE COVER AMOUNTS METHOD FOR OPTIMIZATION OF INCOME

    Directory of Open Access Journals (Sweden)

    A. V. Volkov

    2007-01-01

    Full Text Available The method of cover amounts (marginal income gives possibility to determine profitableness of each kind of the production and their real contribution into the result of work of enterprise.

  5. Amount of Future Forest Edge at a 2 Hectare Scale

    Data.gov (United States)

    U.S. Environmental Protection Agency — Forests provide economic and ecological value. High amounts of forest edge indicates a highly fragmented forest, which generally diminishes those economic and...

  6. Amount of Future Forest Edge at a 65 Hectare scale

    Data.gov (United States)

    U.S. Environmental Protection Agency — Forests provide economic and ecological value. High amounts of forest edge indicates a highly fragmented forest, which generally diminishes those economic and...

  7. Micelle Mediated Trace Level Sulfide Quantification through Cloud Point Extraction

    Directory of Open Access Journals (Sweden)

    Samrat Devaramani

    2012-01-01

    Full Text Available A simple cloud point extraction protocol has been proposed for the quantification of sulfide at trace level. The method is based on the reduction of iron (III to iron (II by the sulfide and the subsequent complexation of metal ion with nitroso-R salt in alkaline medium. The resulting green-colored complex was extracted through cloud point formation using cationic surfactant, that is, cetylpyridinium chloride, and the obtained surfactant phase was homogenized by ethanol before its absorbance measurement at 710 nm. The reaction variables like metal ion, ligand, surfactant concentration, and medium pH on the cloud point extraction of the metal-ligand complex have been optimized. The interference effect of the common anions and cations was studied. The proposed method has been successfully applied to quantify the trace level sulfide in the leachate samples of the landfill and water samples from bore wells and ponds. The validity of the proposed method has been studied by spiking the samples with known quantities of sulfide as well as comparing with the results obtained by the standard method.

  8. More on wormholes supported by small amounts of exotic matter

    OpenAIRE

    Kuhfittig, Peter K. F.

    2005-01-01

    Recent papers by Fewster and Roman have emphasized that wormholes supported by arbitrarily small amounts of exotic matter will have to be incredibly fine-tuned if they are to be traversable. This paper discusses a wormhole model that strikes a balance between two conflicting requirements, reducing the amount of exotic matter and fine-tuning the metric coefficients, ultimately resulting in an engineering challenge: one requirement can only be met at the expense of the other. The wormhole model...

  9. Increasing the amount of payment to research subjects

    OpenAIRE

    2008-01-01

    This article discusses some ethical issues that can arise when researchers decide to increase the amount of payment offered to research subjects to boost enrollment. Would increasing the amount of payment be unfair to subjects who have already consented to participate in the study? This article considers how five different models of payment—the free market model, the wage payment model, the reimbursement model, the appreciation model, and the fair benefits model—would approach this issue. The...

  10. Quantifying meta-correlations in financial markets

    Science.gov (United States)

    Kenett, Dror Y.; Preis, Tobias; Gur-Gershgoren, Gitit; Ben-Jacob, Eshel

    2012-08-01

    Financial markets are modular multi-level systems, in which the relationships between the individual components are not constant in time. Sudden changes in these relationships significantly affect the stability of the entire system, and vice versa. Our analysis is based on historical daily closing prices of the 30 components of the Dow Jones Industrial Average (DJIA) from March 15th, 1939 until December 31st, 2010. We quantify the correlation among these components by determining Pearson correlation coefficients, to investigate whether mean correlation of the entire portfolio can be used as a precursor for changes in the index return. To this end, we quantify the meta-correlation - the correlation of mean correlation and index return. We find that changes in index returns are significantly correlated with changes in mean correlation. Furthermore, we study the relationship between the index return and correlation volatility - the standard deviation of correlations for a given time interval. This parameter provides further evidence of the effect of the index on market correlations and their fluctuations. Our empirical findings provide new information and quantification of the index leverage effect, and have implications to risk management, portfolio optimization, and to the increased stability of financial markets.

  11. Quantifying the synchronizability of externally driven oscillators.

    Science.gov (United States)

    Stefański, Andrzej

    2008-03-01

    This paper is focused on the problem of complete synchronization in arrays of externally driven identical or slightly different oscillators. These oscillators are coupled by common driving which makes an occurrence of generalized synchronization between a driving signal and response oscillators possible. Therefore, the phenomenon of generalized synchronization is also analyzed here. The research is concentrated on the cases of an irregular (chaotic or stochastic) driving signal acting on continuous-time (Duffing systems) and discrete-time (Henon maps) response oscillators. As a tool for quantifying the robustness of the synchronized state, response (conditional) Lyapunov exponents are applied. The most significant result presented in this paper is a novel method of estimation of the largest response Lyapunov exponent. This approach is based on the complete synchronization of two twin response subsystems via additional master-slave coupling between them. Examples of the method application and its comparison with the classical algorithm for calculation of Lyapunov exponents are widely demonstrated. Finally, the idea of effective response Lyapunov exponents, which allows us to quantify the synchronizability in case of slightly different response oscillators, is introduced.

  12. An optimised method for quantifying glenoid orientation

    Directory of Open Access Journals (Sweden)

    Amadi Hippolite

    2008-01-01

    Full Text Available A robust quantification method is essential for inter-subject glenoid comparison and planning of total shoulder arthroplasty. This study compared various scapular and glenoid axes with each other in order to optimally define the most appropriate method of quantifying glenoid version and inclination. Six glenoid and eight scapular axes were defined and quantified from identifiable landmarks of twenty-one scapular image scans. Pathology independency and insensitivity of each axis to inter-subject morphological variation within its region was tested. Glenoid version and inclination were calculated using the best axes from the two regions. The best glenoid axis was the normal to a least-square plane fit on the glenoid rim, directed approximately medio-laterally. The best scapular axis was the normal to a plane formed by the spine root and lateral border ridge. Glenoid inclination was 15.7° ± 5.1° superiorly and version was 4.9° ± 6.1°, retroversion. The choice of axes in the present technique makes it insensitive to pathology and scapular morphological variabilities. Its application would effectively improve inter-subject glenoid version comparison, surgical planning and design of prostheses for shoulder arthroplasty.

  13. Quantifying chemical reactions by using mixing analysis.

    Science.gov (United States)

    Jurado, Anna; Vázquez-Suñé, Enric; Carrera, Jesús; Tubau, Isabel; Pujades, Estanislao

    2015-01-01

    This work is motivated by a sound understanding of the chemical processes that affect the organic pollutants in an urban aquifer. We propose an approach to quantify such processes using mixing calculations. The methodology consists of the following steps: (1) identification of the recharge sources (end-members) and selection of the species (conservative and non-conservative) to be used, (2) identification of the chemical processes and (3) evaluation of mixing ratios including the chemical processes. This methodology has been applied in the Besòs River Delta (NE Barcelona, Spain), where the River Besòs is the main aquifer recharge source. A total number of 51 groundwater samples were collected from July 2007 to May 2010 during four field campaigns. Three river end-members were necessary to explain the temporal variability of the River Besòs: one river end-member is from the wet periods (W1) and two are from dry periods (D1 and D2). This methodology has proved to be useful not only to compute the mixing ratios but also to quantify processes such as calcite and magnesite dissolution, aerobic respiration and denitrification undergone at each observation point.

  14. Quantifying the efficiency of river regulation

    Directory of Open Access Journals (Sweden)

    R. Rödel

    2005-01-01

    Full Text Available Dam-affected hydrologic time series give rise to uncertainties when they are used for calibrating large-scale hydrologic models or for analysing runoff records. It is therefore necessary to identify and to quantify the impact of impoundments on runoff time series. Two different approaches were employed. The first, classic approach compares the volume of the dams that are located upstream from a station with the annual discharge. The catchment areas of the stations are calculated and then related to geo-referenced dam attributes. The paper introduces a data set of geo-referenced dams linked with 677 gauging stations in Europe. Second, the intensity of the impoundment impact on runoff times series can be quantified more exactly and directly when long-term runoff records are available. Dams cause a change in the variability of flow regimes. This effect can be measured using the model of linear single storage. The dam-caused storage change ΔS can be assessed through the volume of the emptying process between two flow regimes. As an example, the storage change ΔS is calculated for regulated long-term series of the Luleälven in northern Sweden.

  15. Quantifying lateral tissue heterogeneities in hadron therapy.

    Science.gov (United States)

    Pflugfelder, D; Wilkens, J J; Szymanowski, H; Oelfke, U

    2007-04-01

    In radiotherapy with scanned particle beams, tissue heterogeneities lateral to the beam direction are problematic in two ways: they pose a challenge to dose calculation algorithms, and they lead to a high sensitivity to setup errors. In order to quantify and avoid these problems, a heterogeneity number H(i) as a method to quantify lateral tissue heterogeneities of single beam spot i is introduced. To evaluate this new concept, two kinds of potential errors were investigated for single beam spots: First, the dose calculation error has been obtained by comparing the dose distribution computed by a simple pencil beam algorithm to more accurate Monte Carlo simulations. The resulting error is clearly correlated with H(i). Second, the analysis of the sensitivity to setup errors of single beam spots also showed a dependence on H(i). From this data it is concluded that H(i) can be used as a criterion to assess the risks of a compromised delivered dose due to lateral tissue heterogeneities. Furthermore, a method how to incorporate this information into the inverse planning process for intensity modulated proton therapy is presented. By suppressing beam spots with a high value of H(i), the unfavorable impact of lateral tissue heterogeneities can be reduced, leading to treatment plans which are more robust to dose calculation errors of the pencil beam algorithm. Additional possibilities to use the information of H(i) are outlined in the discussion.

  16. Computed tomography to quantify tooth abrasion

    Science.gov (United States)

    Kofmehl, Lukas; Schulz, Georg; Deyhle, Hans; Filippi, Andreas; Hotz, Gerhard; Berndt-Dagassan, Dorothea; Kramis, Simon; Beckmann, Felix; Müller, Bert

    2010-09-01

    Cone-beam computed tomography, also termed digital volume tomography, has become a standard technique in dentistry, allowing for fast 3D jaw imaging including denture at moderate spatial resolution. More detailed X-ray images of restricted volumes for post-mortem studies in dental anthropology are obtained by means of micro computed tomography. The present study evaluates the impact of the pipe smoking wear on teeth morphology comparing the abraded tooth with its contra-lateral counterpart. A set of 60 teeth, loose or anchored in the jaw, from 12 dentitions have been analyzed. After the two contra-lateral teeth were scanned, one dataset has been mirrored before the two datasets were registered using affine and rigid registration algorithms. Rigid registration provides three translational and three rotational parameters to maximize the overlap of two rigid bodies. For the affine registration, three scaling factors are incorporated. Within the present investigation, affine and rigid registrations yield comparable values. The restriction to the six parameters of the rigid registration is not a limitation. The differences in size and shape between the tooth and its contra-lateral counterpart generally exhibit only a few percent in the non-abraded volume, validating that the contralateral tooth is a reasonable approximation to quantify, for example, the volume loss as the result of long-term clay pipe smoking. Therefore, this approach allows quantifying the impact of the pipe abrasion on the internal tooth morphology including root canal, dentin, and enamel volumes.

  17. Trace Element Management in Rice

    Directory of Open Access Journals (Sweden)

    Abin Sebastian

    2015-08-01

    Full Text Available Trace elements (TEs are vital for the operation of metabolic pathways that promote growth and structural integrity. Paddy soils are often prone to TE limitation due to intensive cultivation and irrigation practices. Apart from this, rice paddies are potentially contaminated with transition metals such as Cd, which are often referred to as toxic TEs. Deficiency of TEs in the soil not only delays plant growth but also causes exposure of plant roots to toxic TEs. Fine-tuning of nutrient cycling in the rice field is a practical solution to cope with TEs deficiency. Adjustment of soil physicochemical properties, biological process such as microbial activities, and fertilization helps to control TEs mobilization in soil. Modifications in root architecture, metal transporters activity, and physiological processes are also promising approaches to enhance TEs accumulation in grains. Through genetic manipulation, these modifications help to increase TE mining capacity of rice plants as well as transport and trafficking of TEs into the grains. The present review summarizes that regulation of TE mobilization in soil, and the genetic improvement of TE acquisition traits help to boost essential TE content in rice grain.

  18. Fast Ray Tracing NURBS Surfaces

    Institute of Scientific and Technical Information of China (English)

    秦开怀; 龚明伦; 等

    1996-01-01

    In this paper,a new algorithm wit extrapolation process for computing the ray/surface intersection is presented.Also,a ray is defined to be the intersection of two planes,which are non-orthogonal in general,in such a way that the number of multiplication operations is reduced.In the preprocessing step,NURBS surfaces are subdivded adaptively into rational Bezier patches.Parallelepipeds are used to enclose the respective patches as tightly as possible Therefore,for each ray that hits the enclosure(i.e.,parallelepiped)of a patch the intersection points with the parallelepiped's faces can be used to yield a good starting point for the following iteration.The improved Newton iteration with extrapolation process saves CPU time by reducing the number of iteration steps.The intersection scheme is facter than previous methods for which published performance data allow reliable comparison.The method may also be used to speed up tracing the intersection of two parametric surfaces and oter operations that need Newton iteration.

  19. Greenhouse Trace Gases in Deadwood

    Science.gov (United States)

    Covey, Kristofer; Bueno de Mesquita, Cliff; Oberle, Brad; Maynard, Dan; Bettigole, Charles; Crowther, Thomas; Duguid, Marlyse; Steven, Blaire; Zanne, Amy; Lapin, Marc; Ashton, Mark; Oliver, Chad; Lee, Xuhui; Bradford, Mark

    2016-04-01

    Deadwood, long recognized as playing an important role in carbon cycling in forest ecosystems, is more recently drawing attention for its potential role in the cycling of other greenhouse trace gases. We report data from four independent studies measuring internal gas concentrations in deadwood in in three Quercus dominated upland forest systems in the Northeastern and Central United States. Mean methane concentrations in deadwood were 23 times atmospheric levels, indicating a lower bound, mean radial wood surface area flux of ~6 x 10-4 μmol CH4 m-2 s-1. Site, decay class, diameter, and species were all highly significant predictors of methane abundance in deadwood, and log diameter and decay stage interacted as important controls limiting methane concentrations in the smallest and most decayed logs. Nitrous oxide concentrations were negatively correlated with methane and on average ~25% lower than ambient, indicating net consumption of nitrous oxide. These data suggest nonstructural carbohydrates fuel archaeal methanogens and confirm the potential for widespread in situ methanogenesis in both living and deadwood. Applying this understanding to estimate methane emissions from microbial activity in living trees implies a potential global flux of 65.6±12.0 Tg CH4 yr-1, more than 20 times greater than currently considered.

  20. Amount and distribution of collagen in the pancreas have no effect on porcine islet isolation outcome.

    Science.gov (United States)

    Hilling, D; Rijkelijkhuizen, J K R A; Töns, H A M; Terpstra, O T; Bouwman, E

    2009-01-01

    Xenotransplantation of porcine islets of Langerhans is considered to be a possible alternative for clinical islet transplantation. However, porcine islet isolation procedures have been shown to produce highly variable yields between pigs with similar backgrounds. One of the variables that could account for this is the collagen substrate within the pancreas. We determined the amount and distribution of collagen within porcine pancreata as they determined islet isolation outcomes. This study involved the histological examination of 140 porcine pancreata (64 juvenile and 76 adult) and islet isolation from 58 adult organs. To quantify the amount of collagen, tissue samples were stained with Sirius Red. Collagen distribution was determined by assessing the presence of collagen in the endocrine-exocrine interface (the "islet capsule"), in tissue samples double-stained with Sirius Red and anti-insulin. Strong variation in total collagen was observed in both adult and juvenile pigs. The mean collagen content in the juvenile group was significantly lower than that in the adult group. Apparently, the pancreas undergoes a process of fibrosis as pigs age. The vast majority of islets from both adult and juvenile pancreata had no or only a limited collagen capsule. However, islet encapsulation was highly variable between pancreata. We observed no significant correlation between total collagen content or the percentage islet encapsulation and islet yield. Although total collagen content and islet encapsulation show great variability between pancreata, neither the amount nor the distribution of collagen affected porcine islet isolation outcome.

  1. Root responses to nitrogen pulse frequency under different nitrogen amounts

    Science.gov (United States)

    Yuan, Qing-Ye; Wang, Pu; Liu, Lu; Dong, Bi-Cheng; Yu, Fei-Hai

    2017-04-01

    Responses of morphology and biomass allocation of roots to frequency of nitrogen (N) pulse potentially influence the fitness of plants, but such responses may be determined by root size. We grew 12 plant species of three functional groups (grasses, forbs, and legumes) under two N pulse frequencies (high vs. low supply frequency) and two N amounts (high vs. low supply amount). Compared to low-amount N supply, high-amount N supply stimulated biomass accumulation and root growth by either increasing the thickness and length of roots or decreasing the root mass fraction. Compared to low-frequency N supply, high-frequency N supply improved biomass accumulation and root growth in forbs or grasses, but not in legumes. Furthermore, the magnitude of the response to N frequency was significantly negatively correlated with root size at the species scale, but this was only true when the N amount was high. We conclude that root responses to N frequency are related to plant functional types, and non-legume species is more sensitive to N frequency than legume species. Our results also suggest that root size is a determinant of root responses to N frequency when N supply amount is high.

  2. Effect of Source and Amount of Nitrogen, the Amount of Calcium Carbonate of Soil and Different Amounts of Alfalfa Residue on Nitrogen Losses as Ammonia

    Directory of Open Access Journals (Sweden)

    tahereh mansouri

    2017-06-01

    the moisture of soils was brought to field capacity. Samples were placed into special jars and amount of nitrogen volatilization were measured. Results and Discussion: The results showed that ammonia volatilization from soil increased as the concentration of soil calcium carbonate, rates of nitrogen and alfalfa plant residues application increased. In first experiment the highest amount of nitrogen volatilization rate, as ammonia (33.21 µgr N/gr soil was measured from 400kgN/ha soil for urea fertilizer and 35 percent calcium carbonate. Also the lowest amount (11.99 µgrN/gr soil was obtained from 20 percent calcium carbonate without application of any nitrogen fertilizer. In this experiment, with an increase in the amount of soil calcium carbonate by 15%, the amount of volatilized nitrogen in the form of ammonia were six times. By increasing the amount of soil calcium carbonate of from 20 to 27% the amount of nitrogen losses as ammonia slightly increased but with a further increase of calcium carbonate (from 27 to 35% the amount of nitrogen losses increased a lot and this increase was higher than the initial increase. The presence of calcium carbonate in the soil increase soil pH and ammonia volatilization. In second experiment the highest amount of nitrogen volatilization rate, as ammonia (32.28 µgr N/gr soil was measured from 400kgN/ha soil for urea- acid sulfuric fertilizer and 5 percent of plant residues. Also the lowest amount (0.33 µgrN/gr soil was obtained from soil without application of any nitrogen fertilizer and plant residues. The most of nitrogen losses in the form of ammonia in the amount of 15.34 micrograms per gram of soil was obtained from level of 5% of alfalfa residue. With the 2.5 percent increase in the alfalfa residue rate, ammonia volatilization from soil increased in rate of 3.24 micrograms per gram of soil and by increasing it from 2.5 to 5%, nitrogen volatilization increased in the amount of 8.88 micrograms per gram of soil. Conclusion

  3. Trace elements in end-stage renal disease – unfamiliar territory to be revealed

    Directory of Open Access Journals (Sweden)

    Gusbeth-Tatomir Paul

    2009-06-01

    Full Text Available Abstract Although associated with unfavorable outcomes in the general population, abnormal blood levels of various trace elements have not been consistently studied in the end-stage renal disease population (with the notable exception of aluminum. This is surprising, as the uremic patient treated by chronic dialysis loses one major route of trace element excretion and is exposed systematically to a foreign environment (the dialysis fluid possibly contaminated with significant amounts of potential deleterious trace elements. Moreover, some biological important trace elements may be lost through the dialysis membrane. Most studies to date demonstrated significantly altered blood levels of trace elements in ESRD patients compared to healthy controls. However, the biological impact of these abnormalities in renal disease is largely unknown and should be clarified by future studies. A further step would be the design of well-controlled randomized interventional studies, examining the potential therapeutic benefit of supplementing one or more trace elements in ESRD patients, a population characterized by an impressive mortality due to cardiovascular, infectious and neoplasic disease.

  4. Determination of trace metals in drinking water in Irbid City-Northern Jordan.

    Science.gov (United States)

    Alomary, Ahmed

    2013-02-01

    Drinking water samples from Irbid, the second populated city in Jordan were analyzed for trace metals (As, Ba, Cd, Pb, Cr, Cu, Fe, Zn, Mn, Ni, and Se) content. The study was undertaken to determine if the metal concentrations were within the national and international guidelines. A total of 90 drinking water samples were collected from Al-Yarmouk University area. The samples were collected from three different water types: tap water (TW), home-purified water (HPW), and plant-purified water (PPW). All the samples were analyzed for trace metals using an inductively coupled plasma-optical emission spectrometry. All the samples analyzed were within the United States Environmental Protection Agency admissible pH limit (6.5-8.5). The results showed that concentrations of the trace metals vary significantly between the three drinking water types. The results showed that HPW samples have the lowest level of trace metals and the concentrations of some essential trace metals in these samples are less than the recommended amounts. Slight differences in the metal contents were found between HPW samples, little differences between PPW samples; however, significant differences were found between TW samples. Although some TW samples showed high levels of trace metals, however, the mean level of most elements determined in the samples were well within the Jordanian standards as well as the World Health Organization standards for drinking water.

  5. Greenhouse effects due to man-made perturbations of trace gases

    Science.gov (United States)

    Wang, W. C.; Yung, Y. L.; Lacis, A. A.; Mo, T.; Hansen, J. E.

    1976-01-01

    Nitrous oxide, methane, ammonia, and a number of other trace constituents of the earth's atmosphere have infrared absorption bands in the spectral range from 7 to 14 microns. Despite their small amounts, these gases can have a significant effect on the thermal structure of the atmosphere by transmitting most of the thermal radiation from the earth's surface to the lower atmosphere. In the present paper, this greenhouse effect is computed for a number of trace gases. The nature and climatic implications of possible changes in the concentrations of N2O, CH4, NH3, and HNO3 are discussed.

  6. Monitoring the content and intake of trace elements from food in Denmark

    DEFF Research Database (Denmark)

    Larsen, Erik Huusfeldt; Andersen, N. L.; Møller, A.

    2002-01-01

    slightly. The distribution in dietary intake of the five trace elements was estimated by combining the mean trace element concentrations with food consumption data from 1837 Danes aged 15-80 years. The lead intake for 1993-97 showed a decrease in comparison with similar estimates from the previous...... of the distribution in cadmium intake amounts to 34% of PTWI, which is relatively high, and therefore calls for a more detailed future risk assessment. The intakes of lead and mercury were 11% of PTWI and, like the intake of nickel, did not cause any health concern in the adult population. The Danes ingest close...

  7. Decreasing log data of multi-tier services for effective request tracing

    CERN Document Server

    Sang, Bo; Tian, Guanhua

    2010-01-01

    Previous work shows request tracing systems help understand and debug the performance problems of multi-tier services. However, for large-scale data centers, more than hundreds of thousands of service instances provide online service at the same time. Previous work such as white-box or black box tracing systems will produce large amount of log data, which would be correlated into large quantities of causal paths for performance debugging. In this paper, we propose an innovative algorithm to eliminate valueless logs of multitiers services. Our experiment shows our method filters 84% valueless causal paths and is promising to be used in large-scale data centers.

  8. Greenhouse effects due to man-made perturbations of trace gases

    Science.gov (United States)

    Wang, W. C.; Yung, Y. L.; Lacis, A. A.; Mo, T.; Hansen, J. E.

    1976-01-01

    Nitrous oxide, methane, ammonia, and a number of other trace constituents of the earth's atmosphere have infrared absorption bands in the spectral range from 7 to 14 microns. Despite their small amounts, these gases can have a significant effect on the thermal structure of the atmosphere by transmitting most of the thermal radiation from the earth's surface to the lower atmosphere. In the present paper, this greenhouse effect is computed for a number of trace gases. The nature and climatic implications of possible changes in the concentrations of N2O, CH4, NH3, and HNO3 are discussed.

  9. Miniature Tunable Laser Spectrometers for Quantifying Atmospheric Trace Gases, Water Resources, Earth Back-Contamination, and In Situ Resource Utilization

    Science.gov (United States)

    Webster, Chris; Blacksberg, Jordana; Flesch, Greg; Keymeulen, Didier; Christensen, Lance; Forouhar, Siamak

    2012-01-01

    The Tunable Laser Spectrometers (TLS) technique has seen wide applicability in gas measurement and analysis for atmospheric analysis, industrial, commercial and health monitoring and space applications. In Earth science using balloons and aircraft over 2 decades, several groups (JPL, NASA Langley & Ames, NOAA, Harvard U., etc) have demonstrated the technique for ozone hole studies, lab kinetics measurements, cloud physics and transport, climate change in the ice record. The recent availability of high-power (mW) room temperature lasers (TDL, IC, QC) has enabled miniaturized, high-sensitivity spectrometers for industry and space (1) Mars, Titan, Venus, Saturn, Moon (2) Commercial isotope ratio spectrometers are replacing bulkier, complex isotope ratio mass spectrometers.

  10. Use of leaching tests to quantify trace element release from waste to energy bottom ash amended pavements.

    Science.gov (United States)

    Roessler, Justin G; Townsend, Timothy G; Ferraro, Christopher C

    2015-12-30

    A series of roadway tests strips were paved on-site at a landfill in Florida, U.S. Waste to energy (WTE) bottom ash was used as a partial course aggregate replacement in a hot mix asphalt (HMA) and a Portland cement concrete (PCC) pavement, along with control HMA and PCC sections. This allowed for a comparison of the relative degree of leaching between both materials (HMA and PCC) as well as between the ash-amended and control pavements. Batch and monolithic tank leaching tests were conducted on the pavements. Testing of the PCC samples demonstrated that Mo and Al were elevated above regulatory thresholds for both the control and ash amended samples. Further leach testing demonstrated that the release of Mo was likely from the PCC and not a result of the inclusion of the BA into pavement. Batch leach testing of ash-amended HMA samples revealed Sb as a constituent of potential concern. The results of the monolith leaching test displayed leaching of Sb within the same order of magnitude as the regulatory threshold. Calculation of the leachability index (LI) for Sb found that it would have limited mobility when incorporated in the HMA matrix. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Methods for quantifying training in sprint kayak.

    Science.gov (United States)

    Borges, Thiago Oliveira; Bullock, Nicola; Duff, Christine; Coutts, Aaron J

    2014-02-01

    The aims of this study were to determine the validity of the session rating of perceived exertion (session-RPE) method by comparing 3 different scales of perceived exertion with common measures of training load (TL). A secondary aim was to verify the relationship between TLs, fitness, and performance in Sprint Kayak athletes. After laboratory assessment of maximal oxygen uptake (V[Combining Dot Above]O2peak) and lactate threshold, the athletes performed on water time trials over 200 and 1,000 m. Training load was quantified for external (distance and speed) and internal (session-RPE: 6-20, category ratio [CR]-10 and CR-100 scales, training impulse [TRIMP], and individual TRIMP). Ten (6 male, 4 female) well-trained junior Sprint Kayak athletes (age 17.1 ± 1.2 years; V[Combining Dot Above]O2peak 4.2 ± 0.7 L·min) were monitored over a 7-week period. There were large-to-very large within-individual correlations between the session distance and the various heart rate (HR) and RPE-based methods for quantifying TL (0.58-0.91). Correlations between the mean session speed and various HR- and RPE-based methods for quantifying TL were small to large (0.12-0.50). The within-individual relationships between the various objective and subjective methods of internal TL were large to very large (0.62-0.94). Moderate-to-large inverse relationships were found between mean session-RPE TL and various aerobic fitness variables (-0.58 to -0.37). Large-to-very large relationships were found between mean session-RPE TL and on water performance (0.57-0.75). In conclusion, session-RPE is a valid method for monitoring TL for junior Sprint Kayak athletes, regardless of the RPE scale used. The session-RPE TL relates to fitness and performance, supporting the use of session-RPE in Sprint Kayak training.

  12. Model-Based Trace-Checking

    CERN Document Server

    Howard, Y; Gravell, A; Ferreira, C; Augusto, J C

    2011-01-01

    Trace analysis can be a useful way to discover problems in a program under test. Rather than writing a special purpose trace analysis tool, this paper proposes that traces can usefully be analysed by checking them against a formal model using a standard model-checker or else an animator for executable specifications. These techniques are illustrated using a Travel Agent case study implemented in J2EE. We added trace beans to this code that write trace information to a database. The traces are then extracted and converted into a form suitable for analysis by Spin, a popular model-checker, and Pro-B, a model-checker and animator for the B notation. This illustrates the technique, and also the fact that such a system can have a variety of models, in different notations, that capture different features. These experiments have demonstrated that model-based trace-checking is feasible. Future work is focussed on scaling up the approach to larger systems by increasing the level of automation.

  13. Atmospheric Deposition of Trace Elements in Ombrotrophic Peat as a Result of Anthropic Activities

    Science.gov (United States)

    Fabio Lourençato, Lucio; Cabral Teixeira, Daniel; Vieira Silva-Filho, Emmanoel

    2014-05-01

    Ombrotrophic peat can be defined as a soil rich in organic matter, formed from the partial decomposition of vegetable organic material in a humid and anoxic environment, where the accumulation of material is necessarily faster than the decomposition. From the physical-chemical point of view, it is a porous and highly polar material with high adsorption capacity and cation exchange. The high ability of trace elements to undergo complexation by humic substances happens due to the presence of large amounts of oxygenated functional groups in these substances. Since the beginning of industrialization human activities have scattered a large amount of trace elements in the environment. Soil contamination by atmospheric deposition can be expressed as a sum of site contamination by past/present human activities and atmospheric long-range transport of trace elements. Ombrotrophic peat records can provide valuable information about the entries of trace metals into the atmosphere and that are subsequently deposited on the soil. These trace elements are toxic, non-biodegradable and accumulate in the food chain, even in relatively low quantities. Thus studies on the increase of trace elements in the environment due to human activities are necessary, particularly in the southern hemisphere, where these data are scarce. The aims of this study is to evaluate the concentrations of mercury in ombrotrophic peat altomontanas coming from atmospheric deposition. The study is conducted in the Itatiaia National Park, Brazilian conservation unit, situated between the southeastern state of Rio de Janeiro, São Paulo and Minas Gerais. An ombrotrophic peat core is being sampled in altitude (1980m), to measure the trace elements concentrations of this material. As it is conservation area, the trace elements found in the samples is mainly from atmospheric deposition, since in Brazil don't exist significant lithology of trace elements. The samples are characterized by organic matter content which

  14. Analytical methods and validation for determining trace elements in red wines.

    Science.gov (United States)

    Santos, Susana; Lapa, Nuno; Alves, Andreia; Morais, João; Mendes, Benilde

    2013-01-01

    The objective of this work is to quantify As, Hg, Cd, Ni and Pb in Portuguese red wines. First, the methods for the quantification of trace elements in red wines were validated. Several pre-treatments were compared, namely a pre-digestion process with HNO(3), a pre-oxidation step with H(2)O(2), and a spiking step of wine samples with a known concentration of the trace elements analyzed. Except for As, it was determined that the quantification of the trace elements does not require a pre-digestion process with HNO(3). For all of the trace elements analyzed, a pre-oxidation step with H(2)O(2) may enable an accurate quantification. The techniques chosen for the quantification of trace elements were hydride generation atomic absorption spectrometry (HGAAS) for As and Hg, electrothermal atomic absorption spectrometry (ETAAS) for Cd, and flame atomic absorption spectrometry (FAAS) for Ni and Pb. In the second stage of this work, 25 Portuguese red wines spanning all of the red wine-producing regions were analyzed for all of the five trace elements referred to above. Only Cd and Pb have shown concentrations above the limit values defined by the "Organization Internationale de la Vigne et du Vin." The Target Hazard Quotient (THQ) equation was used to determine in which wine-producing regions that wine consumption can be a problem for public health in terms of the concentrations of the five trace elements analyzed. THQ values have indicated that for the universe of the 25 red wines analyzed no region produces wines that can pose problems for public health, when the Portuguese red wine standard consumption is considered.

  15. Climate change and trace gases.

    Science.gov (United States)

    Hansen, James; Sato, Makiko; Kharecha, Pushker; Russell, Gary; Lea, David W; Siddall, Mark

    2007-07-15

    Palaeoclimate data show that the Earth's climate is remarkably sensitive to global forcings. Positive feedbacks predominate. This allows the entire planet to be whipsawed between climate states. One feedback, the 'albedo flip' property of ice/water, provides a powerful trigger mechanism. A climate forcing that 'flips' the albedo of a sufficient portion of an ice sheet can spark a cataclysm. Inertia of ice sheet and ocean provides only moderate delay to ice sheet disintegration and a burst of added global warming. Recent greenhouse gas (GHG) emissions place the Earth perilously close to dramatic climate change that could run out of our control, with great dangers for humans and other creatures. Carbon dioxide (CO2) is the largest human-made climate forcing, but other trace constituents are also important. Only intense simultaneous efforts to slow CO2 emissions and reduce non-CO2 forcings can keep climate within or near the range of the past million years. The most important of the non-CO2 forcings is methane (CH4), as it causes the second largest human-made GHG climate forcing and is the principal cause of increased tropospheric ozone (O3), which is the third largest GHG forcing. Nitrous oxide (N2O) should also be a focus of climate mitigation efforts. Black carbon ('black soot') has a high global warming potential (approx. 2000, 500 and 200 for 20, 100 and 500 years, respectively) and deserves greater attention. Some forcings are especially effective at high latitudes, so concerted efforts to reduce their emissions could preserve Arctic ice, while also having major benefits for human health, agricultural productivity and the global environment.

  16. How to quantify conduits in wood?

    Directory of Open Access Journals (Sweden)

    Alexander eScholz

    2013-03-01

    Full Text Available Vessels and tracheids represent the most important xylem cells with respect to long distance water transport in plants. Wood anatomical studies frequently provide several quantitative details of these cells, such as vessel diameter, vessel density, vessel element length, and tracheid length, while important information on the three dimensional structure of the hydraulic network is not considered. This paper aims to provide an overview of various techniques, although there is no standard protocol to quantify conduits due to high anatomical variation and a wide range of techniques available. Despite recent progress in image analysis programs and automated methods for measuring cell dimensions, density, and spatial distribution, various characters remain time-consuming and tedious. Quantification of vessels and tracheids is not only important to better understand functional adaptations of tracheary elements to environment parameters, but will also be essential for linking wood anatomy with other fields such as wood development, xylem physiology, palaeobotany, and dendrochronology.

  17. Quantifying creativity: can measures span the spectrum?

    Science.gov (United States)

    Simonton, Dean Keith

    2012-01-01

    Because the cognitive neuroscientists have become increasingly interested in the phenomenon of creativity, the issue arises of how creativity is to be optimally measured. Unlike intelligence, which can be assessed across the full range of intellectual ability creativity measures tend to concentrate on different sections of the overall spectrum. After first defining creativity in terms of the three criteria of novelty, usefulness, and surprise, this article provides an overview of the available measures. Not only do these instruments vary according to whether they focus on the creative process, person, or product, but they differ regarding whether they tap into “little-c” versus “Big-C” creativity; only productivity and eminence measures reach into genius-level manifestations of the phenomenon. The article closes by discussing whether various alternative assessment techniques can be integrated into a single measure that quantifies creativity across the full spectrum. PMID:22577309

  18. Message passing for quantified Boolean formulas

    CERN Document Server

    Zhang, Pan; Zdeborová, Lenka; Zecchina, Riccardo

    2012-01-01

    We introduce two types of message passing algorithms for quantified Boolean formulas (QBF). The first type is a message passing based heuristics that can prove unsatisfiability of the QBF by assigning the universal variables in such a way that the remaining formula is unsatisfiable. In the second type, we use message passing to guide branching heuristics of a Davis-Putnam Logemann-Loveland (DPLL) complete solver. Numerical experiments show that on random QBFs our branching heuristics gives robust exponential efficiency gain with respect to the state-of-art solvers. We also manage to solve some previously unsolved benchmarks from the QBFLIB library. Apart from this our study sheds light on using message passing in small systems and as subroutines in complete solvers.

  19. Quantifying decoherence in continuous variable systems

    Energy Technology Data Exchange (ETDEWEB)

    Serafini, A [Dipartimento di Fisica ' ER Caianiello' , Universita di Salerno, INFM UdR Salerno, INFN Sezione Napoli, Gruppo Collegato Salerno, Via S Allende, 84081 Baronissi, SA (Italy); Paris, M G A [Dipartimento di Fisica and INFM, Universita di Milano, Milan (Italy); Illuminati, F [Dipartimento di Fisica ' ER Caianiello' , Universita di Salerno, INFM UdR Salerno, INFN Sezione Napoli, Gruppo Collegato Salerno, Via S Allende, 84081 Baronissi, SA (Italy); De Siena, S [Dipartimento di Fisica ' ER Caianiello' , Universita di Salerno, INFM UdR Salerno, INFN Sezione Napoli, Gruppo Collegato Salerno, Via S Allende, 84081 Baronissi, SA (Italy)

    2005-04-01

    We present a detailed report on the decoherence of quantum states of continuous variable systems under the action of a quantum optical master equation resulting from the interaction with general Gaussian uncorrelated environments. The rate of decoherence is quantified by relating it to the decay rates of various, complementary measures of the quantum nature of a state, such as the purity, some non-classicality indicators in phase space, and, for two-mode states, entanglement measures and total correlations between the modes. Different sets of physically relevant initial configurations are considered, including one- and two-mode Gaussian states, number states, and coherent superpositions. Our analysis shows that, generally, the use of initially squeezed configurations does not help to preserve the coherence of Gaussian states, whereas it can be effective in protecting coherent superpositions of both number states and Gaussian wavepackets. (review article)

  20. Quantifying truncation errors in effective field theory

    CERN Document Server

    Furnstahl, R J; Phillips, D R; Wesolowski, S

    2015-01-01

    Bayesian procedures designed to quantify truncation errors in perturbative calculations of quantum chromodynamics observables are adapted to expansions in effective field theory (EFT). In the Bayesian approach, such truncation errors are derived from degree-of-belief (DOB) intervals for EFT predictions. Computation of these intervals requires specification of prior probability distributions ("priors") for the expansion coefficients. By encoding expectations about the naturalness of these coefficients, this framework provides a statistical interpretation of the standard EFT procedure where truncation errors are estimated using the order-by-order convergence of the expansion. It also permits exploration of the ways in which such error bars are, and are not, sensitive to assumptions about EFT-coefficient naturalness. We first demonstrate the calculation of Bayesian probability distributions for the EFT truncation error in some representative examples, and then focus on the application of chiral EFT to neutron-pr...