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Sample records for base ionophore prior

  1. Development of a disposable mercury ion-selective optode based on trityl-picolinamide as ionophore

    NARCIS (Netherlands)

    Kuswandi, Bambang; Nuriman,; Dam, Henk H.; Reinhoudt, David N.; Verboom, Willem

    2007-01-01

    A disposable ion-selective optode for mercury based on trityl-picolinamide (T-Pico) as neutral ionophore was developed. The sensing layer consist of plasticised PVC incorporating T-Pico as a selective ionophore for Hg2+, ETH 5418 as a chromoionophore, and potassium tetrakis[3,5-bis(trifluoromethyl)p

  2. Development of a disposable mercury ion-selective optode based on tritylpicolinamide as ionophore

    NARCIS (Netherlands)

    Kuswandi, Bambang; Nuriman, [Unknown; Dam, H.H.; Reinhoudt, David; Verboom, Willem

    2007-01-01

    A disposable ion-selective optode for mercury based on trityl-picolinamide (T-Pico) as neutral ionophore was developed. The sensing layer consist of plasticised PVC incorporating T-Pico as a selective ionophore for Hg2+, ETH 5418 as a chromoionophore, and potassium

  3. An Efficient Ag+ Ionophore Based on Thiacalix[4]arene

    Institute of Scientific and Technical Information of China (English)

    LI Xiong; GONG Shu-Ling; YANG Wei-Ping; CHEN Yuan-Yin

    2008-01-01

    A novel Ag+ ionophore, p-tert-butyi-tetrakis(hydrazinocarbonylmethoxy)thiacalix[4]arene in 1,3-alternate conformation (thiacalix[4]arene tetrahydrazide, 1) was synthesized. Its binding properties towards alkali and transition metal cations were studied by noncompetitive liquid-liquid extraction of alkali metal (Li+, Na+, K+ and Cs+)and transition metal (Co2+, Ni2+, Cu2+, Zn2+, Ag+) picrates. It was found that the thiacalix[4]arene tetrahydrazide exhibited high extractability towards Ag+, lower percent extraction towards Cu2+, and little or no extraction ability towards the others. The selectivity towards Ag+ was further evaluated by competitive Ag+ extraction experiments in the mixture of the above-mentioned nine cations, the concentration of which was monitored with ICP-OES. 1HNMR titration experiments and ESI-MS proved the stoichiometry of 1 to Ag+ was 1 : 1, and the 'N-Ag+' interaction with the assistance of thiacalixarene skeleton was primarily involved in the complexation.

  4. A Solid-Contact Indium(III) Sensor based on a Thiosulfinate Ionophore Derived from Omeprazole

    Energy Technology Data Exchange (ETDEWEB)

    Abbas, Mohammad Nooredeen; Hend Samy Amer [National Research Centre, Cairo (Egypt)

    2013-04-15

    A novel solid-contact indium(III)-selective sensor based on bis-(1H-benzimidazole-5-methoxy-2-[(4-methoxy-3, 5-dimethyl-1-pyridinyl) 2-methyl]) thiosulfinate, known as an omeprazole dimer (OD) and a neutral ionophore, was constructed, and its performance characteristics were evaluated. The sensor was prepared by applying a membrane cocktail containing the ionophore to a graphite rod pre-coated with polyethylene dioxythiophene (PEDOT) conducting polymer as the ion-to-electron transducer. The membrane contained 3.6% OD, 2.3% oleic acid (OA) and 62% dioctyl phthalate (DOP) as the solvent mediator in PVC and produced a good potentiometric response to indium(III) ions with a Nernstian slope of 19.09 mV/decade. The constructed sensor possessed a linear concentration range from 3 Χ 10{sup -7} to 1 Χ 10{sup -2} M and a lower detection limit (LDL) of 1 Χ 10{sup -7} M indium(III) over a pH range of 4.0-7.0. It also displayed a fast response time and good selectivity for indium(III) over several other ions. The sensor can be used for longer than three months without any considerable divergence in potential. The sensor was utilized for direct and flow injection potentiometric (FIP) determination of indium(III) in alloys. The parameters that control the flow injection method were optimized. Indium(III) was quantitatively recovered, and the results agreed with those obtained using atomic absorption spectrophotometry, as confirmed by the f and t values. The sensor was also utilized as an indicator electrode for the potentiometric titration of fluoride in the presence of chloride, bromide, iodide and thiocyanate ions using indium(III) nitrate as the titrant.

  5. Fluorous polymeric membranes for ionophore-based ion-selective potentiometry: how inert is Teflon AF?

    Science.gov (United States)

    Lai, Chun-Ze; Koseoglu, Secil S; Lugert, Elizabeth C; Boswell, Paul G; Rábai, József; Lodge, Timothy P; Bühlmann, Philippe

    2009-02-04

    Fluorous media are the least polar and polarizable condensed phases known. Their use as membrane materials considerably increases the selectivity and robustness of ion-selective electrodes (ISEs). In this research, a fluorous amorphous perfluoropolymer was used for the first time as a matrix for an ISE membrane. Electrodes for pH measurements with membranes composed of poly[4,5-difluoro-2,2-bis(trifluoromethyl)-1,3-dioxole]-co-poly(tetrafluoroethylene) (87% dioxole monomer content; known as Teflon AF2400) as polymer matrix, a linear perfluorooligoether as plasticizer, sodium tetrakis[3,5-bis(perfluorohexyl)phenyl]borate providing for ionic sites, and bis[(perfluorooctyl)propyl]-2,2,2-trifluoroethylamine as H+ ionophore were investigated. All electrodes had excellent potentiometric selectivities, showed Nernstian responses to H+ over a wide pH range, exhibited enhanced mechanical stability, and maintained their selectivity over at least 4 weeks. For membranes of low ionophore concentration, the polymer affected the sensor selectivity noticeably at polymer concentrations exceeding 15%. Also, the membrane resistance increased quite strongly at high polymer concentrations, which cannot be explained by the Mackie-Meares obstruction model. The selectivities and resistances depend on the polymer concentration because of a functional group associated with Teflon AF2400, with a concentration of one functional group per 854 monomer units of the polymer. In the fluorous environment of these membranes, this functional group binds to Na+, K+, Ca2+, and the unprotonated ionophore with binding constants of 10(3.5), 10(1.8), 10(6.8), and 10(4.4) M(-1), respectively. Potentiometric and spectroscopic evidence indicates that these functional groups are COOH groups formed by the hydrolysis of carboxylic acid fluoride (COF) groups originally present in Teflon AF2400. The use of higher ionophore concentrations removes the undesirable effect of these COOH groups almost completely

  6. ATOX1 gene silencing increases susceptibility to anticancer therapy based on copper ionophores or chelating drugs.

    Science.gov (United States)

    Barresi, Vincenza; Spampinato, Giorgia; Musso, Nicolò; Trovato Salinaro, Angela; Rizzarelli, Enrico; Condorelli, Daniele Filippo

    2016-03-01

    Copper is a catalytic cofactor required for the normal function of many enzymes involved in fundamental biological processes but highly cytotoxic when in excess. Therefore its homeostasis and distribution is strictly regulated by a network of transporters and intracellular chaperones. ATOX1 (antioxidant protein 1) is a copper chaperone that plays a role in copper homeostasis by binding and transporting cytosolic copper to ATPase proteins in the trans-Golgi network. In the present study the Caco-2 cell line, a colon carcinoma cell line, was used as an in vitro model to evaluate if ATOX1 deficiency could affect sensitivity to experimentally induced copper dyshomeostasis. Silencing of ATOX1 increased toxicity of a short treatment with a high concentration of Cu(2+). Copper ionophores, such as 5-chloro-8-hydroxyquinoline, induced a copper-dependent cell toxicity which was significantly potentiated after ATOX1 silencing. The copper chelator TPEN (N,N,N',N'-tetrakis (2-pyridylmethyl) ethylenediamine) produced a form of cell toxicity that was reversed by the addition of Cu(2+). ATOX1 silencing increased Caco-2 cell sensitivity to TPEN toxicity. Our results suggest the possibility of a therapy with copper-chelating or ionophore drugs in subtypes of tumors showing specific alterations in ATOX1 expression.

  7. Potentiometric Response Characteristics of Membrane-Based Cs+-Selective Electrodes Containing Ionophore-Functionalized Polymeric Microspheres

    Directory of Open Access Journals (Sweden)

    Shane Peper

    2011-01-01

    Full Text Available Cs+-selective solvent polymeric membrane-based ion-selective electrodes (ISEs were developed by doping ethylene glycol-functionalized cross-linked polystyrene microspheres (P-EG into a plasticized poly(vinyl chloride (PVC matrix containing sodium tetrakis-(3,5-bis(trifluoromethylphenyl borate (TFPB as the ion exchanger. A systematic study examining the effects of the membrane plasticizers bis(2-ethylhexyl sebacate (DOS, 2-nitrophenyl octyl ether (NPOE, and 2-fluorophenyl nitrophenyl ether (FPNPE on the potentiometric response and selectivity of the corresponding electrodes was performed. Under certain conditions, P-EG-based ion-selective electrodes (ISEs containing TFPB and plasticized with NPOE exhibited a super-Nernstian response between 1×10−3 and 1×10−4 M Cs+, a response characteristic not observed in analogous membranes plasticized with either DOS or FPNPE. Additionally, the performance of P-EG-based ISEs was compared to electrodes based on two mobile ionophores, a neutral lipophilic ethylene glycol derivative (ethylene glycol monooctadecyl ether (U-EG and a charged metallacarborane ionophore, sodium bis(dicarbollylcobaltate(III (CC. In general, P-EG-based electrodes plasticized with FPNPE yielded the best performance, with a linear range from 10-1–10-5 M Cs+, a conventional lower detection limit of 8.1×10−6 M Cs+, and a response slope of 57.7 mV/decade. The pH response of P-EG ISEs containing TFPB was evaluated for membranes plasticized with either NPOE or FPNPE. In both cases, the electrodes remained stable throughout the pH range 3–12, with only slight proton interference observed below pH 3.

  8. Ionophore-based potentiometric PVC membrane sensors for determination of phenobarbitone in pharmaceutical formulations.

    Science.gov (United States)

    Alrabiah, Haitham; Al-Majed, Abdulrahman; Abounassif, Mohammed; Mostafa, Gamal A E

    2016-12-01

    The fabrication and development of two polyvinyl chloride (PVC) membrane sensors for assaying phenobarbitone sodium are described. Sensors 1 and 2 were fabricated utilizing β- or γ-cyclodextrin as ionophore in the presence of tridodecylmethylammonium chloride as a membrane additive, and PVC and dioctyl phthalate as plasticizer. The analytical parameters of both sensors were evaluated according to the IUPAC guidelines. The proposed sensors showed rapid, stable anionic response (-59.1 and -62.0 mV per decade) over a relatively wide phenobarbitone concentration range (5.0 × 10-6-1 × 10-2 and 8 × 10-6-1 × 10-2 mol L-1) in the pH range of 9-11. The limit of detection was 3.5 × 10-6 and 7.0 × 10-6 mol L-1 for sensors 1 and 2, respectively. The fabricated sensors showed high selectivity for phenobarbitone over the investigated foreign species. An average recovery of 2.54 μg mL-1 phenobarbitone sodium was 97.4 and 101.1 %, while the mean relative standard deviation was 3.0 and 2.1 %, for sensors 1 and 2, respectively. The results acquired for determination of phenobarbitone in its dosage forms utilizing the proposed sensors are in good agreement with those obtained by the British Pharmacopoeial method.

  9. Ionophore-based potentiometric PVC membrane sensors for determination of phenobarbitone in pharmaceutical formulations

    Directory of Open Access Journals (Sweden)

    Alrabiah Haitham

    2016-12-01

    Full Text Available The fabrication and development of two polyvinyl chloride (PVC membrane sensors for assaying phenobarbitone sodium are described. Sensors 1 and 2 were fabricated utilizing β- or γ-cyclodextrin as ionophore in the presence of tridodecylmethylammonium chloride as a membrane additive, and PVC and dioctyl phthalate as plasticizer. The analytical parameters of both sensors were evaluated according to the IUPAC guidelines. The proposed sensors showed rapid, stable anionic response (-59.1 and -62.0 mV per decade over a relatively wide phenobarbitone concentration range (5.0 × 10-6-1 × 10-2 and 8 × 10-6-1 × 10-2 mol L-1 in the pH range of 9-11. The limit of detection was 3.5 × 10-6 and 7.0 × 10-6 mol L-1 for sensors 1 and 2, respectively. The fabricated sensors showed high selectivity for phenobarbitone over the investigated foreign species. An average recovery of 2.54 μg mL-1 phenobarbitone sodium was 97.4 and 101.1 %, while the mean relative standard deviation was 3.0 and 2.1 %, for sensors 1 and 2, respectively. The results acquired for determination of phenobarbitone in its dosage forms utilizing the proposed sensors are in good agreement with those obtained by the British Pharmacopoeial method.

  10. Ionophores in the Environment

    DEFF Research Database (Denmark)

    Bak, Søren Alex; Hansen, Martin; Björklund, Erland

    ) and antiparacitics (i.e. ionophores) posses an environmental effects of similar level as their parent compounds on i.e. the soil bacterial community (Halling-Sørensen et al.2002; Hansen et al. 2009). Ionophores are used extensively worldwide as prophylactic chemotherapeutics and growth promoters in livestock...... production. Ionophores are antibiotic drugs that form lipid soluble complexes with, primarily, alkali cations that inhibit or kill pathogenic parasites in livestock. Several reports have revealed that ionophores are emerging environmental contaminants in agricultural run-off waters, surface waters, sediments......-001-0017-2 Hansen M, Krogh KA, Brandt A, Christensen JH, Halling-Sorensen B (2009) Environmental Pollution 157: 2 p. 474-480. DOI:10.1016/j.envpol.2008.09.022...

  11. Highly selective detection of silver in the low ppt range with ion-selective electrodes based on ionophore-doped fluorous membranes.

    Science.gov (United States)

    Lai, Chun-Ze; Fierke, Melissa A; Corrêa da Costa, Rosenildo; Gladysz, John A; Stein, Andreas; Bühlmann, Philippe

    2010-09-15

    Ionophore-doped sensing membranes exhibit greater selectivities and wider measuring ranges if their membrane matrixes are noncoordinating and solvate interfering ions poorly. This is particularly true for fluorous phases, which are the least polar and polarizable condensed phases known. In this work, fluorous membrane matrixes were used to prepare silver ion-selective electrodes (ISEs). Sensing membranes composed of perfluoroperhydrophenanthrene, sodium tetrakis[3,5-bis(perfluorohexyl) phenyl]borate, and one of four fluorophilic Ag(+)-selective ionophores with one or two thioether groups were investigated. All electrodes exhibited Nernstian responses to Ag(+) in a wide range of concentrations. Their selectivities for Ag(+) over interfering ions were found to depend on host preorganization and the length of the -(CH(2))(n)- spacers separating the coordinating thioether group from the strongly electron withdrawing perfluoroalkyl groups. ISEs based on the most selective of the four ionophores, that is, 1,3-bis(perfluorodecylethylthiomethyl)benzene, provided much higher selectivities for Ag(+) over many alkaline and heavy metal ions than most Ag(+) ISEs reported in the literature (e.g., log K(Ag,J)(pot) for K(+), -11.6; Pb(2+), -10.2; Cu(2+), -13.0; Cd(2+), -13.2). Moreover, the use of this ionophore with a linear perfluorooligoether as membrane matrix and solid contacts consisting of three-dimensionally ordered macroporous (3DOM) carbon resulted in a detection limit for Ag(+) of 4.1 ppt (3.8 × 10(-1)1 M).

  12. A solid-contact pH-selective electrode based on tridodecylamine as hydrogen neutral ionophore

    Science.gov (United States)

    Zhang, Jianxin; Guo, Yixuan; Li, Shangjin; Xu, Hui

    2016-10-01

    The solid-state pH electrode has the potential possibility to be used in many extreme situations with satisfactory accuracy and low cost. But its performance is affected by the solid electrolyte, preparation process, and the structure of the sensitive membrane, etc. In this work, the relationships between these factors and the characteristic of the prepared electrode were verified by controlling the preparation conditions with a variety of electrochemical methods. Firstly, the solid electrolyte poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) was electrochemically deposited on the screen-printed carbon electrode (SPCE) substrate by a potentiostatic method in an aqueous solution containing 0.01 M 3,4-ethylenedioxythiophene (EDOT) and 0.1 M polystyrene sulfonic (PSS) acid as the supporting electrolyte. The PEDOT films were then characterized by cyclic voltammetry (CV) in the 0.1 M NaNO3 aqueous solution in order to obtain the optimized polymerization potential and charges where the PEDOT film would have a higher redox capacitance. Finally, the pH electrode was prepared by coating the SPCE/PEDOT(PSS) with a plasticized polyvinyl chloride (PVC) membrane containing tridodecylamine as hydrogen ionophore manually, and experiments were carried out to study the effect of the usage of PVC per square millimeter on the response time and stability of the electrode to optimize the PVC film thickness. The potentiometric response of the pH electrode was studied in the buffer solutions with pH ranging from 5.00 to 10.81 by the open-circuit potential (OCP) method. Experimental results show that the sensitivity of the electrode is  -55.7  ±  0.5 mV pH-1 (r 2  >  0.9980) at room temperature (24  ±  1 °C) with pH ranging from 2.00-10.50, approximating to the theoretical nernstian slope (-59.16 mV pH-1),and the response time was less than 10 s. Moreover, it has low impedance, high accuracy and potential stability as well as some

  13. Miniaturized ionophore-based potentiometric sensors for the flow-injection determination of metformin in pharmaceutical formulations and biological fluids.

    Science.gov (United States)

    Khaled, Elmorsy; Kamel, Manal S; Hassan, Hassan N; Abd El-Alim, Sameh H; Aboul-Enein, Hassan Y

    2012-12-01

    Miniaturized potentiometric sensors based on β-cyclodextrins (β-CDs) are described for determination of metformin (Mf) in pharmaceutical preparations and biological fluids. Electrode matrix compositions are optimized on the basis of the nature and content of sensing ionophore, ionic sites and plasticizers. Coated wire electrodes (CWEs) modified with heptakis(2,3,6-tri-O-methyl)-β-CD, sodium tetrakis(4-fluorophenyl)borate (NaTFPB) and 2-fluorophenyl 2-nitrophenyl ether (f-NPE), work satisfactorily in the concentration range from 10(-6) to 10(-1) mol L(-1) with Nernstian compliance (55.7 ± 0.4 mV per decade activity) and a detection limit of 8 × 10(-7) mol L(-1). Incorporation of β-CD as a molecular recognition element improved the electrode sensitivity and selectivity due to encapsulation of Mf into the β-CD cavity (host-guest interaction). The developed electrodes have been successfully applied for the potentiometric determination of Mf under batch and flow injection analysis (FIA). FIA allows analysis of 90 samples per h offering the advantages of simplicity, accuracy and automation feasibility. The dissolution profile for metformin pharmaceutical samples (Cidophage®) was monitored using the proposed electrode in comparison with the official spectrophotometric methods. Characterization of the formed Mf-β-CD inclusion complexes is discussed in detail.

  14. Salicylate-selective Potential Response of an Electrode Based on a Copper(Ⅱ)-phthalocyanine Derivative as an Ionophore

    Institute of Scientific and Technical Information of China (English)

    XU Wenju; YUAN Ruo; CHAI Yaqin

    2009-01-01

    Selectivity properties were established for salicylate-selective electrodes prepared by incorporating 2,9,16,23-copper(Ⅱ)-tetranitrophthalocyanine (Cu(Ⅱ)TNPc) and 2,9,16,23-copper(Ⅱ)-tetraaminophthalocyanine (Cu(Ⅱ)TAPc) into plasticized poly(vinyl chloride) (PVC) membranes. The effect of nature of plasticizer, concentrations of iono-phore and anionic and cationic additives on the potential response of the electrode was investigated. The PVC membrane electrode based on Cu(Ⅱ)TNPc exhibited preferential selectivity for salicylate (Sal-) over other tested anions. The best potential response characteristics of a wide working concentration range 1.0×10-1-9.0×10-7 the membrane containing (w/w) 3.0% Cu(II)TNPc, 67.0% o-NPOE, 29.5% PVC, and 0.5% NaTPB. The proposed electrode with good stability and fast response could be used over a pH range of 3.0-7.0. And it was successfully applied to the determination of salicylate in actual samples with satisfactory results.

  15. Development of a specific and highly sensitive optical chemical sensor for determination of Hg(II) based on a new synthesized ionophore.

    Science.gov (United States)

    Firooz, Ali R; Ensafi, Ali A; Karimi, K; Sharghi, H

    2013-10-01

    A novel optode for determination of Hg(II) ions is developed based on immobilization of a recently synthesized ionophore, 7-(1H-imidazol-1-ylmethyl)-5,6,7,8,9,10-hexahydro-2H-1,13,4,7,10 benzodioxatriaza cyclopentadecine-3,11(4H,12H)-dione, in a PVC membrane. Dioctyl sebacate was used as a plasticizer, sodium tetraphenylborate as an anionic additive and ETH5294 as a chromoionophore. The response of the optode was based on the complexation of Hg(II) with the ionophore in the membrane phase, resulting an ion exchange process between Hg(II) in the sample solution and H(+) in the membrane. The effects of pH and amounts of the ionophore, chromoionophore, ionic additive and type of plasticizer on the optode response were investigated. The selectivity of the optode was studied in the present of several cations. The optode has a linear response to Hg(II) in the range of 7.2×10(-13)-4.7×10(-4) mol L(-1) with detection limit of 0.18 pmol L(-1). The optode was successfully applied to the determination of Hg(II) in real samples. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Effects of ionophores and antibiotics on in vitro hydrogen sulfide production, dry matter disappearance, and total gas production in cultures with a steam-flaked corn-based substrate with or without added sulfur.

    Science.gov (United States)

    Quinn, M J; May, M L; Hales, K E; DiLorenzo, N; Leibovich, J; Smith, D R; Galyean, M L

    2009-05-01

    Effects of 3 ionophores and 2 antibiotics on in vitro H(2)S production, IVDMD, total gas production, and VFA profile with or without added S were examined. In Exp. 1, ruminal fluid from 2 ruminally cannulated steers fed a steam-flaked corn-based diet (75% concentrate) without ionophore and antibiotics for 28 d before collection was used to inoculate in vitro cultures. Treatments were control (no ionophore or antibiotic), 3 ionophores (lasalocid sodium and monensin sodium at 5 mg/L or laidlomycin propionate at 1.65 mg/L), and 2 antibiotics (chlortetracycline hydrochloride at 5 mg/L and tylosin tartarate at 1.25 mg/L). Cultures also had 0 or 1.75 mg of S/L (from sodium sulfate). No S x ionophore-antibiotic treatment interactions were noted (P > 0.53) for IVDMD, total gas production, and H(2)S production. Hydrogen sulfide (mumol/g of fermentable DM) was increased (P production tended (P = 0.09) to be increased with additional S; however, IVDMD was not affected by added S (P = 0.90). Production of H(2)S was not affected by ionophores or antibiotics (P > 0.18). On average, IVDMD (P = 0.05) was greater for ionophores than for antibiotics, whereas total gas production was less for ionophores than for control (P antibiotics (P 0.20) in acetate, propionate, or acetate:propionate between ionophores and control (S x treatment interaction, P = 0.03). In Exp. 2, the effects of ionophore-antibiotic combinations with added S were examined using the same procedures as in Exp. 1. Treatments were control, monensin plus tylosin (MT), and lasalocid plus chlortetracycline (LCTC), with concentrations of the ionophores and antibiotics as in Exp. 1. No differences were observed among treatments for H(2)S production (P > 0.55). Treatments MT and LCTC tended (P = 0.06) to increase IVDMD and decreased (P = 0.02) gas production vs. control. Proportion of acetate (P = 0.01) and acetate:propionate (P antibiotics we evaluated did not affect production of H(2)S gas in an in vitro rumen culture

  17. Advanced selective non-invasive ketone body detection sensors based on new ionophores

    Science.gov (United States)

    Sathyapalan, A.; Sarswat, P. K.; Zhu, Y.; Free, M. L.

    2014-12-01

    New molecules and methods were examined that can be used to detect trace level ketone bodies. Diseases such as type 1 diabetes, childhood hypo-glycaemia-growth hormone deficiency, toxic inhalation, and body metabolism changes are linked with ketone bodies concentration. Here we introduce, selective ketone body detection sensors based on small, environmentally friendly organic molecules with Lewis acid additives. Density functional theory (DFT) simulation of the sensor molecules (Bromo-acetonaphthone tungstate (BANT) and acetonaphthophenyl ether propiono hydroxyl tungstate (APPHT)), indicated a fully relaxed geometry without symmetry attributes and specific coordination which enhances ketone bodies sensitivity. A portable sensing unit was made in which detection media containing ketone bodies at low concentration and new molecules show color change in visible light as well as unique irradiance during UV illumination. RGB analysis, electrochemical tests, SEM characterization, FTIR, absorbance and emission spectroscopy were also performed in order to validate the ketone sensitivity of these new molecules.

  18. Ionophore-Based Potentiometric Sensors for the Flow-Injection Determination of Promethazine Hydrochloride in Pharmaceutical Formulations and Human Urine

    Directory of Open Access Journals (Sweden)

    Suad Mustafa Al-Araji

    2011-01-01

    Full Text Available Plasticised poly(vinyl chloride-based membranes containing the ionophores (α-, β- and γ-cyclodextrins (CD, dibenzo-18-crown-6 (DB18C6 and dibenzo-30-crown-10 (DB30C10 were evaluated for their potentiometric response towards promethazine (PM in a flow injection analysis (FIA set-up. Good responses were obtained when β- and γ-CDs, and DB30C10 were used. The performance characteristics were further improved when tetrakis(4-chlorophenyl borate (KTPB was added to the membrane. The sensor based on β-CD, bis(2-ethylhexyl adipate (BEHA and KTPB exhibited the best performance among the eighteen sensor compositions that were tested. The response was linear from 1 x 10−5 to 1 x 10−2 M, slope was 61.3 mV decade−1, the pH independent region ranged from 4.5 to 7.0, a limit of detection of 5.3 x 10−6 M was possible and a lifetime of more than a month was observed when used in the FIA system. Other plasticisers such as dioctyl phenylphosphonate and tributyl phosphate do not show significant improvements in the quality of the sensors. The promising sensors were further tested for the effects of foreign ions (Li+, Na+, K+, Mg2+, Ca2+, Co2+, Cu2+, Cr3+, Fe3+, glucose, fructose. FIA conditions (e.g., effects of flow rate, injection volume, pH of the carrier stream were also studied when the best sensor was used (based on β-CD. The sensor was applied to the determination of PM in four pharmaceutical preparations and human urine that were spiked with different levels of PM. Good agreement between the sensor and the manufacturer’s claimed values (for pharmaceutical preparations was obtained, while mean recoveries of 98.6% were obtained for spiked urine samples. The molecular recognition features of the sensors as revealed by molecular modelling were rationalised by the nature of the interactions and complexation energies between the host and guest molecules.

  19. Plasticizer-free microspheres for ionophore-based sensing and extraction based on a methyl methacrylate-decyl methacrylate copolymer matrix

    Energy Technology Data Exchange (ETDEWEB)

    Peper, Shane; Ceresa, Alan; Qin Yu; Bakker, Eric

    2003-12-19

    Plasticizer-free methyl methacrylate-decyl methacrylate (MMA-DMA) microspheres were prepared under mild, non-reactive conditions using a high-throughput particle generator. The particles were perfectly smooth and monodisperse, with a particle diameter of approximately 10.0 {mu}m. In order to evaluate the suitability of the polymer as a matrix for bulk extraction processes, lipophilic sensing components were incorporated into the particles. Particles contained either a H{sup +}-selective chromoionophore (ETH 5294) only (type 1), or a K{sup +}-selective ionophore (BME-44), anionic sites (NaTFPB), and ETH 5294 (type 2). Type 1 particles responded according to an anion-proton coextraction mechanism and demonstrated Hofmeister selectivity by showing a preference for more lipophilic sample anions (ClO{sub 4}{sup -}>NO{sub 3}{sup -}>Cl{sup -}). Particles of type 2 functioned by way of an ion-exchange equilibrium and demonstrated a functional response for K{sup +}, with a dynamic range from 10{sup -1}-10{sup -4} M K{sup +}. These particles also exhibited selectivity comparable to that previously reported for analogous particles made from bis(2-ethylhexyl sebacate) (DOS)-plasticized poly(vinyl chloride) (PVC) and DMA-DOS. In addition, the behavior of both types1 and 2 particles was in agreement with analogous thin film optical sensors (optodes) prepared from MMA-DMA. With the advent of ionophore-based plasticizer-free microspheres a wide variety of ions may potentially be assessed using various popular bead-based sensing strategies, such as lab-on-a-chip technologies, bundled optical fiber arrays, and flow cytometry, without experiencing the deleterious effects resultant of plasticizer leaching.

  20. Abiotic degradation of antibiotic ionophores

    DEFF Research Database (Denmark)

    Bohn, Pernille; Bak, Søren A; Björklund, Erland

    2013-01-01

    Hydrolytic and photolytic degradation were investigated for the ionophore antibiotics lasalocid, monensin, salinomycin, and narasin. The hydrolysis study was carried out by dissolving the ionophores in solutions of pH 4, 7, and 9, followed by incubation at three temperatures of 6, 22, and 28 °C f...... because they absorb light of environmentally irrelevant wavelengths....

  1. Electroanalytical performance of a terbium(III)-selective sensor based on a neutral ionophore in environmental and medicinal samples

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, V.K.; Singh, A.K.; Gupta, Barkha [Indian Institute of Technology-Roorkee, Department of Chemistry, Roorkee (India)

    2008-04-15

    A new highly selective terbium(III) electrode was prepared with a polymeric film doped using S-2-benzothiazolyl-2-amino-{alpha}-(methoxyimino)-4-thiazolethiol acetate as an electroactive material, benzyl acetate (BA) as a plasticizer, and potassium tetrakis(4-chlorophenyl) borate (KTpClPB) as an anionic site in the percentage ratio 3.17:1.58:63.4:31.7 (ionophore-KTpClPB-BA-PVC, w/w). The electrode exhibited a linear response with a near Nernstian slope of 19.5 mV/decade within the concentration range 1.5 x 10{sup -7}-1.0 x 10{sup -2} M terbium ions, with a working pH range from 2.0 to 8.0, and a fast response time of 10 s and presented satisfactory reproducibility. The limit of detection was 9.3 x 10{sup -8} M. The results show that this electrode can be used in ethanol media up to 30% (v/v) concentration without interference. It can be used for 3 months without any considerable divergence in the potentials. Selectivity coefficients for terbium(III) with respect to many cations were investigated. The electrode is highly selective for terbium(III) ions over a large number of monovalent, bivalent, and trivalent cations. This shows the valuable property of the proposed electrode. The stability constant of the ionophore towards Tb{sup 3+} ions was determined with the sandwich membrane method. It was successfully used as an indicator electrode in potentiometric determination of terbium(III) ions with EDTA and in direct determination in tap water and binary mixtures with quantitative results. The utility of the proposed electrode was also determined in the presence of ionic and nonionic surfactants and in the presence of fluoride ions in four pharmaceutical (mouthwash) preparations. (orig.)

  2. Zinc selective ionophores for potentiometric and optical sensors

    Energy Technology Data Exchange (ETDEWEB)

    Lindner, E.; Horvath, M.; Toth, K.; Pungor, E.; Bitter, I.; Agai, B.; Toeke, L. (Technical Univ. of Budapest (Hungary))

    1992-03-01

    Iminodiacetamide derivatives were synthesized and studied as ionophores in plasticized poly(vinyl chloride) membranes with potentiometric and optical transduction. The N-benzyl and N-phenyl derivatives proved to have a distinct zinc selectivity preferring Zn{sup 2+} over Ca{sup 2+}, Na{sup +} by factors of 6x10{sup 5} and 3x10{sup 4}, respectively. All ionophores exhibit a serious proton interference (log K{sup pot}{sub Zn{sup ++}}, {sub H{sup +}} {approximately} 6) which suggests that all application of this type of ionophores based sensors are limited to hydrogen ion buffer solution at pH {>=} 6.

  3. The Novel SCN''- Ion-selective Electrode Based on the 1-Benzyl-3-(4-nitrophenyl) thio-urea Ionophore

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyung Mi; Kang, Dong Hyeon; Choe, Ju Eun; You, Jung Min; Go, Min Jeong; Lee, Jung Seong; Jeon, Seung Won [Chungnam National University, Daejeon (Korea, Republic of)

    2014-09-15

    A potentiometric sensor based on the 1-benzyl-3-(4-nitrophenyl) thio-urea was synthesized and tested as an ionophore in PVC based membrane sensor towards SCN - ions. This membrane exhibits a linear stable response over a wide concentration range (1.0 × 10''-5 to 1.0 × 10''-2 M) with a slope of -59.2 mV/dec., a detection limit of log[SCN''- ] = -5.05, and a selectivity coefficient for thiocyanate against perchlorate anion of logK{sub s}cn''pot = -0.133. The selectivity series of the membrane is as follows: SCN''- > ClO{sub 4}''- > I''- >NO{sub 3}''- >HSO{sub 3}''- > Cl''-HSO{sub '}'-''4 > F''- > CH{sub 3}COO''- > HCO''-''3 > Br''- > H{sub 2}PO{sub 4}''- > SO{sub 3}''-''2 > SO{sub 4}''-''2 > CO{sub 3}''-''2. The proposed electrode showed good selectivity and a good response for the SCN''- ion over a wide variety of other anions in pH 6.0 buffer solutions and has a fast response time of about < 5s.. The influences of the membrane by pH, ionophore, and plasticizer were studied.

  4. Fabrication of new carbon paste electrodes based on gold nano-particles self-assembled to mercapto compounds as suitable ionophores for potentiometric determination of copper ions

    Directory of Open Access Journals (Sweden)

    Rasoul Pourtaghavi Talemi

    2013-12-01

    Full Text Available In the present study, we investigate the potentiometric behavior of Cu2+ carbon paste electrodes based on two mercapto compounds 2-ethylmino-5-mercapto-1,3,4-thiadiazole (EAMT and 2-acetylamino-5-mercapto-1,3,4-thiadiazole (AAMT self-assembled on gold nano-paricle (GNP as ionophore. Then, the obtained results from the modified electrodes are compared. The self-assembled ionophores exhibit a high selectivity for copper ion (Cu2+, in which the sulfur and nitrogen atoms in their structure play a significant role as the effective coordination donor site for the copper ion. Among these electrodes, the best performance was obtained with the sensor with a EAMT/graphite powder/paraffin oil weight ratio of 4.0/68/28 with 200 µL of GNP which exhibits the working concentration range of 1.6×10−9 to 6.3×10−2 M and a nernstian slope of 28.9±0.4 mVdecade−1 of copper(II activity. The detection limit of electrode was 2.9(±0.2×10−10M and potential response was pH ; in other words, it was independent across the range of 2.8–6.3. The proposed electrode presented very good selectivity and sensitivity towards the Cu2+ ions over a wide variety of cations including alkali, alkaline earth, transition and heavy metal ions. Moreover, the proposed electrode was successfully applied as an indicator electrode in the potentiometric titration of Cu(II ions with EDTA and also the potentiometric determination of copper ions in spiked water samples.

  5. Fabrication of a highly selective cadmium (II) sensor based on 1,13-bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane as a supramolecular ionophore

    Energy Technology Data Exchange (ETDEWEB)

    Ghaemi, Arezoo, E-mail: arezooghaemi@yahoo.com; Tavakkoli, Haman; Mombeni, Tayebeh

    2014-05-01

    A new cadmium (II) ion selective sensor based on 1,13-bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane (kryptofix5) as a supramolecular carrier has been developed. The membrane solutions containing polyvinyl chloride (PVC), plasticizer, sodium tetraphenylborate (NaTPB) as a lipophilic ionic additive and kryptofix5 as an ionophore were directly coated on the surface of graphite rods. The best composition of the coated membrane (w/w%) was found to be: 30.0% PVC, 61.0% dioctyl sebacate (DOS), 6.0% NaTPB and 3.0% kryptofix5. The sensor indicates a good linear response for Cd{sup 2+} cation over a wide concentration range from 1.0 × 10{sup −5} to 1.0 × 10{sup −1} M with a Nernstian slope of 29.8 ± 0.1 mV/decade and the detection limit is 8.4 × 10{sup −6} M. The response time of the sensor is 15 s and it can be used for 7 weeks without significant drift in potential. The sensor operates in the wide pH range of 1.0–6.0. This sensor reveals a very good selectivity toward Cd{sup 2+} ion over a wide range of alkali, transition and heavy metal cations. The sensor was used as an indicator electrode for potentiometric titration of Cd{sup 2+} using sodium fluoride and ethylenediaminetetraacetic acid (EDTA) solutions with a sharp potential change that occurred at the end point. In addition, the proposed sensor was successfully used for determination of Cd{sup 2+} cation in real water samples. - Graphical abstract: Fabrication of a highly selective cadmium (II) sensor based on 1,13-bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane as a supramolecular ionophore. - Highlights: • Fabrication of a novel Cd{sup 2+} selective sensor with high sensitivity and selectivity • Using fabricated sensor in a wide pH range with fast response time • Replacing expensive techniques with this low cost sensor with low detection limit • Excellent capability of this sensor for measuring Cd{sup 2+} in real samples.

  6. Erbium(Ⅲ) PVC membrane sensor based on N-(benzyloxycarbonyloxy)succinimide as a new neutral ionophore

    Institute of Scientific and Technical Information of China (English)

    Hassan Ali Zamani

    2011-01-01

    In this study, a new Er3+ sensor based on N-(benzyloxycarbonyloxy)succinimide (BCS) as a neutral carrier has been constructed. The sensor exhibits potential linear response with a Nernstian slope of 20.5 ± 0.4 mV/decade in the concentration range of 1.0 × 10-6 to 1.0 × 10-2 mol/L of Er3+. It has a very short response time (<10 s), detection limit of 6.3 × 10-7 mol/L and a good selectivity relative to a wide variety of other metal ions including common alkali, alkaline earth, heavy, and transition metal ions. It can be used in the pH range of 2.5-10.6 without any considerable divergence in potentials. The proposed sensor was successfully applied for the recovery of Er3+ ions spiked in tap and river water samples.

  7. Logarithmic Laplacian Prior Based Bayesian Inverse Synthetic Aperture Radar Imaging.

    Science.gov (United States)

    Zhang, Shuanghui; Liu, Yongxiang; Li, Xiang; Bi, Guoan

    2016-04-28

    This paper presents a novel Inverse Synthetic Aperture Radar Imaging (ISAR) algorithm based on a new sparse prior, known as the logarithmic Laplacian prior. The newly proposed logarithmic Laplacian prior has a narrower main lobe with higher tail values than the Laplacian prior, which helps to achieve performance improvement on sparse representation. The logarithmic Laplacian prior is used for ISAR imaging within the Bayesian framework to achieve better focused radar image. In the proposed method of ISAR imaging, the phase errors are jointly estimated based on the minimum entropy criterion to accomplish autofocusing. The maximum a posterior (MAP) estimation and the maximum likelihood estimation (MLE) are utilized to estimate the model parameters to avoid manually tuning process. Additionally, the fast Fourier Transform (FFT) and Hadamard product are used to minimize the required computational efficiency. Experimental results based on both simulated and measured data validate that the proposed algorithm outperforms the traditional sparse ISAR imaging algorithms in terms of resolution improvement and noise suppression.

  8. Transformation of ionophore antimicrobials in poultry litter during pilot-scale composting.

    Science.gov (United States)

    Munaretto, Juliana S; Yonkos, Lance; Aga, Diana S

    2016-05-01

    Ionophores are the second top selling class of antimicrobials used in food-producing animals in the United States. In chickens, ionophores are used as feed additives to control coccidiosis; up to 80% of administered ionophores are excreted in the litter. Because poultry litter is commonly used to fertilize agricultural fields, ionophore residues in litter have become contaminants of emerging concern. This study aims to develop a liquid chromatography with tandem mass spectrometry (LC-MS/MS) method to quantify ionophores, and identify their transformation products (TPs) in poultry litter after on-farm pilot-scale composting. The validation parameters of the optimized method showed good accuracy, ranging from 71 to 119% recovery and relative standard deviation (precision) of ≤19% at three different concentration levels (10, 50 and 100 μg/kg). Monensin, salinomycin and narasin, were detected in the poultry litter samples prior to composting at 290.0 ± 40, 426 ± 46, and 3113 ± 318 μg kg(-1), respectively. This study also aims to investigate the effect of different composting conditions on the removal of ionophores, such as the effect of turning or aeration. Results revealed a 13-68% reduction in ionophore concentrations after 150 d of composting, depending on whether the compost was aerated, turned, or subjected to a combination of both aeration and turning. Three transformation products and one metabolite of ionophores were identified in the composted litter using high-resolution liquid chromatography with quadrupole time-of-flight mass spectrometry (LC-QToF/MS).

  9. Chloroquine is a zinc ionophore.

    Directory of Open Access Journals (Sweden)

    Jing Xue

    Full Text Available Chloroquine is an established antimalarial agent that has been recently tested in clinical trials for its anticancer activity. The favorable effect of chloroquine appears to be due to its ability to sensitize cancerous cells to chemotherapy, radiation therapy, and induce apoptosis. The present study investigated the interaction of zinc ions with chloroquine in a human ovarian cancer cell line (A2780. Chloroquine enhanced zinc uptake by A2780 cells in a concentration-dependent manner, as assayed using a fluorescent zinc probe. This enhancement was attenuated by TPEN, a high affinity metal-binding compound, indicating the specificity of the zinc uptake. Furthermore, addition of copper or iron ions had no effect on chloroquine-induced zinc uptake. Fluorescent microscopic examination of intracellular zinc distribution demonstrated that free zinc ions are more concentrated in the lysosomes after addition of chloroquine, which is consistent with previous reports showing that chloroquine inhibits lysosome function. The combination of chloroquine with zinc enhanced chloroquine's cytotoxicity and induced apoptosis in A2780 cells. Thus chloroquine is a zinc ionophore, a property that may contribute to chloroquine's anticancer activity.

  10. On structure-based priors in Bayesian geophysical inversion

    Science.gov (United States)

    de Pasquale, G.; Linde, N.

    2017-03-01

    Bayesian methods are extensively used to analyse geophysical data sets. A critical and somewhat overlooked component of high-dimensional Bayesian inversion is the definition of the prior probability density function that describes the joint probability of model parameters before considering available data sets. If insufficient prior information is available about model parameter correlations, then it is tempting to assume that model parameters are uncorrelated. When working with a spatially gridded model representation, this overparametrization leads to posterior realizations with far too much variability to be deemed realistic from a geological perspective. In this study, we introduce a new approach for structure-based prior sampling with Markov chain Monte Carlo that is suitable when only limited prior information is available. We evaluate our method using model structure measures related to standard roughness and damping metrics for l1- and l2-norms. We show that our structure-based prior approach is able to adequately sample the chosen prior distribution of model structure. The usefulness and applicability of the methodology is demonstrated on synthetic and field-based crosshole ground penetrating radar data. We find that our method provides posterior model realizations and statistics that are significantly more satisfactory than those based on underlying assumptions of uncorrelated model parameters or on explicit penalties on model structure within an empirical Bayes framework.

  11. Region-based active contour with noise and shape priors

    CERN Document Server

    Lecellier, François; Fadili, Jalal; Aubert, Gilles; Revenu, Marinette; Saloux, Eric

    2008-01-01

    In this paper, we propose to combine formally noise and shape priors in region-based active contours. On the one hand, we use the general framework of exponential family as a prior model for noise. On the other hand, translation and scale invariant Legendre moments are considered to incorporate the shape prior (e.g. fidelity to a reference shape). The combination of the two prior terms in the active contour functional yields the final evolution equation whose evolution speed is rigorously derived using shape derivative tools. Experimental results on both synthetic images and real life cardiac echography data clearly demonstrate the robustness to initialization and noise, flexibility and large potential applicability of our segmentation algorithm.

  12. Platinum porphyrins as ionophores in polymeric membrane electrodes

    DEFF Research Database (Denmark)

    Lvova, Larisa; Verrelli, Giorgio; Nardis, Sara

    2011-01-01

    porphyrin dimers occurs in the membrane plasticized both with high or low dielectric constant plasticizer, due to a low oxophilicity of central Pt. The computational study of various anion–Pt(IV)TPPCl2 complex formation by means of semi-empirical and density functional theory (DFT) methods revealed a good......A comparative study of Pt(II)- and Pt(IV)-porphyrins as novel ionophores for anion-selective polymeric membrane electrodes is performed. Polymeric membranes of different compositions, prepared by varying plasticizers, cationic and anionic additives and Pt porphyrins, have been examined...... within the electrode membranes, while those based on Pt(IV)TPPCl2 operate via a mixed mode carrier mechanism, evidencing also a partial reduction of the starting ionophore to Pt(II)TPP. Spectrophotometric measurements of thin polymeric films indicate that no spontaneous formation of hydroxide ion bridged...

  13. Logarithmic Laplacian Prior Based Bayesian Inverse Synthetic Aperture Radar Imaging

    Directory of Open Access Journals (Sweden)

    Shuanghui Zhang

    2016-04-01

    Full Text Available This paper presents a novel Inverse Synthetic Aperture Radar Imaging (ISAR algorithm based on a new sparse prior, known as the logarithmic Laplacian prior. The newly proposed logarithmic Laplacian prior has a narrower main lobe with higher tail values than the Laplacian prior, which helps to achieve performance improvement on sparse representation. The logarithmic Laplacian prior is used for ISAR imaging within the Bayesian framework to achieve better focused radar image. In the proposed method of ISAR imaging, the phase errors are jointly estimated based on the minimum entropy criterion to accomplish autofocusing. The maximum a posterior (MAP estimation and the maximum likelihood estimation (MLE are utilized to estimate the model parameters to avoid manually tuning process. Additionally, the fast Fourier Transform (FFT and Hadamard product are used to minimize the required computational efficiency. Experimental results based on both simulated and measured data validate that the proposed algorithm outperforms the traditional sparse ISAR imaging algorithms in terms of resolution improvement and noise suppression.

  14. Squalamine is not a proton ionophore.

    Science.gov (United States)

    Selinsky, B S; Smith, R; Frangiosi, A; Vonbaur, B; Pedersen, L

    2000-03-15

    Squalamine, an aminosterol antibiotic isolated from the dogfish shark, creates relatively large defects in phospholipid bilayers, allowing the unrestricted translocation of small molecules across these compromised membranes (B.S. Selinsky, Z. Zhou, K.G. Fotjik, S. R. Jones, N.R. Dollahon, A.E. Shinnar, Biochim. Biophys. Acta 1370 (1998) 218-234). However, an aminosterol structurally similar to squalamine was found to act as a proton ionophore in anionic phospholipid vesicles. In contrast with squalamine, gross membrane disruption was not observed with this synthetic analog (G. Deng, T. Dewa, S.L. Regen, J. Am. Chem. Soc. 118 (1996) 8975-8976). In this report, the ionophoric activity of squalamine was tested in anionic and zwitterionic phospholipid vesicles. No ionophoric activity was observed for squalamine in vesicles comprised of phosphatidylglycerol (PG), phosphatidylcholine (PC), or a mixture of the two lipids. Experiments using radiolabeled squalamine indicated that all of the squalamine added to PG vesicles remained with the vesicles, while approximately one-half of the squalamine added to PC vesicles was incorporated. We have synthesized the aminosterol analog of squalamine possessing ionophoric activity, and its ionophoric activity in PG vesicles was confirmed. The synthetic compound possessed no measurable lytic activity when added to preformed phospholipid vesicles. As both compounds possess significant antimicrobial activity, these results suggest that either multiple mechanisms for the antimicrobial activity of aminosterols exist, depending upon the aminosterol structure, or possibly an unrelated common mechanism for antimicrobial activity remains to be discovered.

  15. Prior-based artifact correction (PBAC) in computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Heußer, Thorsten, E-mail: thorsten.heusser@dkfz-heidelberg.de; Brehm, Marcus [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Ritschl, Ludwig [Ziehm Imaging GmbH, Donaustraße 31, 90451 Nürnberg (Germany); Sawall, Stefan; Kachelrieß, Marc [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany and Institute of Medical Physics, Friedrich–Alexander–University (FAU) of Erlangen–Nürnberg, Henkestraße 91, 91052 Erlangen (Germany)

    2014-02-15

    Purpose: Image quality in computed tomography (CT) often suffers from artifacts which may reduce the diagnostic value of the image. In many cases, these artifacts result from missing or corrupt regions in the projection data, e.g., in the case of metal, truncation, and limited angle artifacts. The authors propose a generalized correction method for different kinds of artifacts resulting from missing or corrupt data by making use of available prior knowledge to perform data completion. Methods: The proposed prior-based artifact correction (PBAC) method requires prior knowledge in form of a planning CT of the same patient or in form of a CT scan of a different patient showing the same body region. In both cases, the prior image is registered to the patient image using a deformable transformation. The registered prior is forward projected and data completion of the patient projections is performed using smooth sinogram inpainting. The obtained projection data are used to reconstruct the corrected image. Results: The authors investigate metal and truncation artifacts in patient data sets acquired with a clinical CT and limited angle artifacts in an anthropomorphic head phantom data set acquired with a gantry-based flat detector CT device. In all cases, the corrected images obtained by PBAC are nearly artifact-free. Compared to conventional correction methods, PBAC achieves better artifact suppression while preserving the patient-specific anatomy at the same time. Further, the authors show that prominent anatomical details in the prior image seem to have only minor impact on the correction result. Conclusions: The results show that PBAC has the potential to effectively correct for metal, truncation, and limited angle artifacts if adequate prior data are available. Since the proposed method makes use of a generalized algorithm, PBAC may also be applicable to other artifacts resulting from missing or corrupt data.

  16. Language-Based Prior Knowledge and Transition to Mathematics

    Science.gov (United States)

    Dogan-Dunlap, Hamide; Torres, Cristina; Chen, Fan

    2005-01-01

    The paper provides a college mathematics student's concept maps, definitions, and essays to support the thesis that language-based prior knowledge can influence students' cognitive processes of mathematical concepts. A group of intermediate algebra students who displayed terms mainly from the spoken language on the first and the second concept…

  17. A highly sensitive and selective bulk optode based on benzimidazol derivative as an ionophore and ETH5294 for the determination of ultra trace amount of silver ions.

    Science.gov (United States)

    Firooz, Ali R; Ensafi, Ali A; Kazemifard, Nafiseh; Sharghi, Hashem

    2012-11-15

    A novel optical chemical sensor (optode) was fabricated for the determination of silver ions. The optical sensor was prepared by incorporating recently synthesized ionophore, 7-(1H-benzimidazol-1-ylmethyl)-5,6,7,8,9,10-hexahydro-2H-1,13,4,7,10-benzodioxatriaza cyclopentadecine-3,11(4H,12H)-dione, sodium tetraphenyl borate (NaTPB) as an anionic additive, 3-octadecanoylimino-7-(diethylamino)-1,2-benzophenoxazine (ETH5294) as a chromoionophore, and dioctyl phthalate (DOP) as a plasticizer in a poly(vinyl chloride) membrane. The effect of several parameters in determining Ag(+) was studied and optimized. The spectrophotometric method (λ(max) of 660 nm) was used for the determination of Ag(+). Under the optimum conditions, the optical sensor has a wide dynamic range of 1.02×10(-11) to 8.94×10(-5) mol L(-1) Ag(+) with the detection limit as low as 2.8×10(-12) mol L(-1). The response time of the sensor was ~150 s, with a RSD% of 0.4% (for 1.0×10(-6) mol L(-1), n=7). The optode could be regenerated by 0.2 mol L(-1) HCl solution. The interferences of potential interfering ions were studied. It was shown that the new optode was very selective to silver ions and had no significant response to common ions such as Mn(2+), Cd(2+), Ni(2+), Hg(2+), and Co(2+). It can be claimed that the sensor can specifically detect silver ions. The sensor was successfully applied for the determination of silver ions in different real samples. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. Inhibition of resistance plasmid transfer in Escherichia coli by ionophores, chlortetracycline, bacitracin, and ionophore/antimicrobial combinations.

    Science.gov (United States)

    Mathers, Jeremy J; Clark, Steven R; Hausmann, Denny; Tillman, Paul; Benning, Valerie R; Gordon, Shelly K

    2004-01-01

    Medicinal feed additives bacitracin, chlortetracycline (CTC), laidlomycin, lasalocid, and salinomycin inhibited the transfer of multiresistance-conferring plasmid pBR325 (Tet(r) Amp(r) Cp(r), 6.0 kb) into selected gram-negative strains with the use of an in vitro model. High concentrations of ampicillin-sensitive competence-pretreated Escherichia coli HB 101 cells were exposed to 10% (v/v) of 1:10 dimethyl sulfoxide/agent : water containing test mixtures for 0.5 hr prior to plasmid addition and transforming conditions. Transformation was inhibited for all antimicrobials and showed a positive association wich higher concentration. Additional testing of ionophore compounds separately and in combination with bacitracin, chlortetracycline, lincomycin, roxarsone, tylosin, and virginiamycin at representative feed concentrations demonstrated 80.6% to >99.9% inhibition (P < 0.001) of resistance transfer. Bacitracin alone inhibited transformation within the range of 50-500 ppm. No increase in resistance transfer was observed when poultry-derived and reference gram-negative isolates having low or no transformation efficiency were additionally tested. The results suggest that these compounds, at relevant concentrations used in animal feed, may interfere with cell envelope-associated DNA uptake channels or other transformation competence mechanisms. Through these mechanisms, ionophores and cell membrane-interactive feed agents such as CTC and bacitracin may act to inhibit resistance transfer mechanisms within poultry and livestock.

  19. Probabilistic contour extraction based on shape prior model

    Institute of Scientific and Technical Information of China (English)

    FAN Xin; LIANG De-qun

    2005-01-01

    Statistical shape prior model is employed to construct the dynamics in probabilistic contour estimation.By applying principal component analysis,plausible shape samples are efficiently generated to predict contour samples.Based on the shape-dependent dynamics and probabilistic image model,a particle filter is used to estimate the contour with a specific shape.Compared with the deterministic approach with shape information,the proposed method is simple yet more effective in extracting contours from images with shape variations and occlusion.

  20. Macrocyclic compound as ionophores in lead(Ⅱ)ion-selective electrodes with excellent response characteristics

    Institute of Scientific and Technical Information of China (English)

    HUANG MeiRong; MA XiaoLi; LI XinGui

    2008-01-01

    Macrocyclic compounds, such as crown ethers, azacrown ethers, thiacrown ethers, calixarenes and porphyrins, which act as ionophores in lead(Ⅱ) ion-selective electrodes, are systematically summarized based on the latest literatures. The molecular structure characteristics of the ionophores are general-ized. The modification regulations for the substituted ionophores are elaborated with the purpose ofimproving the response features of the lead(Ⅱ) ion-selective electrodes assembled by them. It is pointed out that the introduction of pendant moieties which contain soft base coordination centers like N, S and P atoms is in favor of adjusting the cavity size and conformation of the macrocyclic com-pounds. Furthermore, there is synergic effect between the cavity and the donor sites of the ligand and thus the selective complexation of lead ions is easily realized, resulting in significant avoidance of the interference from other metal ions. The macrocyclic ionophore having the best response characteris-tics thus far was found to be N,N'-dimethylcyanodiaza-18-crown-6 with the detection limit of 7.0×10-8 (14.5 μg/L), which is one of the uncommon ionophores that can really eliminate the interference from silver and mercury ions. The selectivity coefficients of the ionophore for lead ions over other metal ions, such as alkali, alkaline earth and transition metal ions are in the order of 10-4 or smaller, where the se-lectivity coefficient of lead(Ⅱ) over mercury(Ⅱ) ions is much lower, down to 8.9×10-4. The structure de-sign idea for high-performance ionophore is proposed according to present results. The incorporation of nitrogen atom, especially cyano group or thiocyano group or amino/imino groups, rather than thio atom alone could result in new excellent lead ionophores. The aborative design for metacyclophanes containing aromatic nitrogen atoms with the aim of creating excellent ionophores would also become a potential research trend. The lead(Ⅱ) ion

  1. Salinomycin, a polyether ionophoric antibiotic, inhibits adipogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Szkudlarek-Mikho, Maria; Saunders, Rudel A. [Department of Medicine, Biochemistry and Cancer Biology, Center for Diabetes and Endocrine Research, College of Medicine, University of Toledo, Toledo, OH 43614 (United States); Yap, Sook Fan [Faculty of Medicine and Health Sciences, Department of Pre-Clinical Sciences, University of Tunku Abdul Rahman (Malaysia); Ngeow, Yun Fong [Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603 (Malaysia); Chin, Khew-Voon, E-mail: khew-voon.chin@utoledo.edu [Department of Medicine, Biochemistry and Cancer Biology, Center for Diabetes and Endocrine Research, College of Medicine, University of Toledo, Toledo, OH 43614 (United States)

    2012-11-30

    Highlights: Black-Right-Pointing-Pointer Salinomycin inhibits preadipocyte differentiation into adipocytes. Black-Right-Pointing-Pointer Salinomycin inhibits transcriptional regulation of adipogenesis. Black-Right-Pointing-Pointer Pharmacological effects of salinomycin suggest toxicity in cancer therapy. -- Abstract: The polyether ionophoric antibiotics including monensin, salinomycin, and narasin, are widely used in veterinary medicine and as food additives and growth promoters in animal husbandry including poultry farming. Their effects on human health, however, are not fully understood. Recent studies showed that salinomycin is a cancer stem cell inhibitor. Since poultry consumption has risen sharply in the last three decades, we asked whether the consumption of meat tainted with growth promoting antibiotics might have effects on adipose cells. We showed in this report that the ionophoric antibiotics inhibit the differentiation of preadipocytes into adipocytes. The block of differentiation is not due to the induction of apoptosis nor the inhibition of cell proliferation. In addition, salinomycin also suppresses the transcriptional activity of the CCAAT/enhancer binding proteins and the peroxisome proliferator-activated receptor {gamma}. These results suggest that the ionophoric antibiotics can be exploited as novel anti-obesity therapeutics and as pharmacological probes for the study of adipose biology. Further, the pharmacological effects of salinomycin could be a harbinger of its toxicity on the adipose tissue and other susceptible target cells in cancer therapy.

  2. A simple liposome assay for the screening of zinc ionophore activity of polyphenols.

    Science.gov (United States)

    Clergeaud, Gael; Dabbagh-Bazarbachi, Husam; Ortiz, Mayreli; Fernández-Larrea, Juan B; O'Sullivan, Ciara K

    2016-04-15

    An efficient liposomal system for screening the zinc ionophore activity of a selected library consisting of the most relevant dietary polyphenols is presented. The zinc ionophore activity was demonstrated by exploring the use of zinc-specific fluorophore FluoZin-3 loaded liposomes as simple membrane tools that mimic the cell membrane. The zinc ionophore activity was demonstrated as the capacity of polyphenols to transport zinc cations across the liposome membrane and increase the zinc-specific fluorescence of the encapsulated fluorophore FluoZin-3. In addition, the zinc chelation strength of the polyphenols was also tested in a competition assay based on the fluorescence quenching of zinc-dependent fluorescence emitted by zinc-FluoZin-3 complex. Finally, the correlation between the chelation capacity and ionophore activity is demonstrated, thus underlining the sequestering or ionophoric activity that the phenolic compounds can display, thus, providing better knowledge of the importance of the structural conformation versus their biological activity. Furthermore, the assays developed can be used as tools for rapid, high-throughput screening of families of polyphenols towards different biometals.

  3. 以硫代乙酰胺/凹凸棒石复合物为载体的钙离子选择性电极%A New Calcium Electrode Based on the Composite Thioacetamide/attapulgite as Ionophore

    Institute of Scientific and Technical Information of China (English)

    李文卓; 黄方伦; 王健龙

    2012-01-01

    报道了以硫代乙酰胺/凹凸棒石有机无机复合物为载体的新型钙离子选择性电极的研制.探讨了该有机无机复合物中硫代乙酰胺与凹凸棒石的组成比例、增塑剂用量、被测溶液pH等因素对钙电极性能的影响.结果表明新制钙电极对溶液中的钙离子有较好的近能斯特响应,响应斜率为15.2 mV decade-1,最低检出下限为1.0×10-6mol L-1.新制钙电极具有很好的稳定性,其可应用在溶液pH=6.0~10.0范围内.新电极对常见阳离子表现出好的抗干扰性.利用红外、紫外、相关电导率实验等方法研究了有机无机复合物型电活性物质的结构及所制钙电极的工作机理.%A kind of novel organic/inorganic composites as ionophore in the membrane of calcium ion selective electrode,which were made of thioacetamide and attapulgite,had been prepared.Thioacetamide is a type of small organic molecule with functional groups including amino groups and carbon-sulfur double bonds.Attapulgite has been characterized by a high negative charge at its surface,a large specific surface area,and a large micropore volume due to the existence of intercrystalline cavities.Thioacetamide molecules can carry positive charges when their amino groups get protons from hydroxyl groups of attapulgite.So thioacetamide molecules with positive charges can be adsorbed on the negative surface of attapulgite by electrostatic interaction as well as hydrogen-bonding,to form a super-molecular host-guest structure.Considering the stagger arranged pores on the outer surface of attapulgite,we inferred that adsorbed thioacetamide molecules should be around the edge of pore mouth of the attapulgite.Experiments proved that the organic/inorganic complex structure promoted the ability of attapulgite adsorbing more calcium ions from the solution.Based on the attapulgite/thioacetamide composite as ionophore,the calcium ion selective electrodes were prepared using 7.0 wt% of ionophore,43.0 wt

  4. Immobilization of ionophore and surface characterization studies of the titanium(III) ion in a PVC-membrane sensor.

    Science.gov (United States)

    Rezayi, Majid; Heng, Lee Yook; Kassim, Anuar; Ahmadzadeh, Saeid; Abdollahi, Yadollah; Jahangirian, Hossein

    2012-01-01

    Novel ionophores comprising various hydroxide and amine structures were immobilized onto poly(vinyl chloride) (PVC) matrices, and these were examined to determine Ti(III) selectivity. To predict the selectivity of Ti(III), a PVC membrane was used to investigate the binding of Ti(III) to c-methylcalix[4]resorcinarene (CMCR). The study showed that the chelating ligand, CMCR, was coordinated selectively to Ti(III) at eight coordination sites involving the oxygen atoms at the interface of the membrane/solution. The membrane was prepared, based on CMCR as an ionophore, sodium tetrakis(4-fluorophenyl) borate (NaTFPB) as a lipophilic ionic additive, and dioctylphthalate (DOP) as a plasticizer. The immobilization of the ionophore and surface characterization studies revealed that the performance of CMCR-immobilized PVC was equivalent to that of mobile ionophores in supported liquid membranes (SLMs). The strengths of the ion-ionophore (CMCR-Ti(OH)(OH(2))(5) (2+)) interactions and the role of ionophores on membranes were studied via UV-Vis, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and and X-ray diffraction (XRD).

  5. Immobilization of Ionophore and Surface Characterization Studies of the Titanium(III Ion in a PVC-Membrane Sensor

    Directory of Open Access Journals (Sweden)

    Majid Rezayi

    2012-06-01

    Full Text Available Novel ionophores comprising various hydroxide and amine structures were immobilized onto poly(vinyl chloride (PVC matrices, and these were examined to determine Ti(III selectivity. To predict the selectivity of Ti(III, a PVC membrane was used to investigate the binding of Ti(III to c-methylcalix[4]resorcinarene (CMCR. The study showed that the chelating ligand, CMCR, was coordinated selectively to Ti(III at eight coordination sites involving the oxygen atoms at the interface of the membrane/solution. The membrane was prepared, based on CMCR as an ionophore, sodium tetrakis(4-fluorophenyl borate (NaTFPB as a lipophilic ionic additive, and dioctylphthalate (DOP as a plasticizer. The immobilization of the ionophore and surface characterization studies revealed that the performance of CMCR-immobilized PVC was equivalent to that of mobile ionophores in supported liquid membranes (SLMs. The strengths of the ion-ionophore (CMCR-Ti(OH(OH252+ interactions and the role of ionophores on membranes were studied via UV-Vis, Fourier transform infrared spectroscopy (FT–IR, scanning electron microscopy (SEM and and X-ray diffraction (XRD.

  6. Curvature Prior for MRF-based Segmentation and Shape Inpainting

    CERN Document Server

    Shekhovtsov, Alexander; Rother, Carsten

    2011-01-01

    Most image labeling problems such as segmentation and image reconstruction are fundamentally ill-posed and suffer from ambiguities and noise. Higher order image priors encode high level structural dependencies between pixels and are key to overcoming these problems. However, these priors in general lead to computationally intractable models. This paper addresses the problem of discovering compact representations of higher order priors which allow efficient inference. We propose a framework for solving this problem which uses a recently proposed representation of higher order functions where they are encoded as lower envelopes of linear functions. Maximum a Posterior inference on our learned models reduces to minimizing a pairwise function of discrete variables, which can be done approximately using standard methods. Although this is a primarily theoretical paper, we also demonstrate the practical effectiveness of our framework on the problem of learning a shape prior for image segmentation and reconstruction....

  7. Occurrence of Ionophores in the Danish Environment

    Directory of Open Access Journals (Sweden)

    Søren Alex Bak

    2014-11-01

    Full Text Available Antibiotics in the environment are a potential threat to environmental ecosystems as well as human health and safety. Antibiotics are designed to have a biological effect at low doses, and the low levels detected in the environment have turned focus on the need for more research on environmental occurrence and fate, to assess the risk and requirement for future regulation. This article describes the first occurrence study of the antibiotic polyether ionophores (lasalocid, monensin, narasin, and salinomycin in the Danish environment. Various environmental matrices (river water, sediment, and soil have been evaluated during two different sampling campaigns carried out in July 2011 and October 2012 in an agricultural area of Zealand, Denmark. Lasalocid was not detected in any of the samples. Monensin was measured at a concentration up to 20 ng·L−1 in river water and 13 µg·kg−1 dry weight in the sediment as well as being the most frequently detected ionophore in the soil samples with concentrations up to 8 µg·kg−1 dry weight. Narasin was measured in sediment samples at 2 µg·kg−1 dry weight and in soil between 1 and 18 µg·kg−1 dry weight. Salinomycin was detected in a single soil sample at a concentration of 30 µg·kg−1 dry weight.

  8. 49 CFR 240.205 - Procedures for determining eligibility based on prior safety conduct.

    Science.gov (United States)

    2010-10-01

    ... prior conduct as a railroad worker, and § 240.119 involving substance abuse disorders and alcohol/drug... prior safety conduct. 240.205 Section 240.205 Transportation Other Regulations Relating to... determining eligibility based on prior safety conduct. (a) Each railroad, prior to initially certifying...

  9. Metal artifact reduction based on the combined prior image

    CERN Document Server

    Zhang, Yanbo

    2014-01-01

    Metallic implants introduce severe artifacts in CT images, which degrades the image quality. It is an effective method to reduce metal artifacts by replacing the metal affected projection with the forward projection of a prior image. How to find a good prior image is the key of this class methods, and numerous algorithms have been proposed to address this issue recently. In this work, by using image mutual correlation, pixels in the original reconstructed image or linear interpolation corrected image, which are less affected by artifacts, are selected to build a combined image. Thereafter, a better prior image is generated from the combined image by using tissue classification. The results of three patients' CT images show that the proposed method can reduce metal artifacts remarkably.

  10. Copper(II)-selective fluorimetric bulk optode membrane based on a 1-hydroxy-9,10-anthraquinone derivative having two propenyl arms as a neutral fluorogenic ionophore.

    Science.gov (United States)

    Shamsipur, Mojtaba; Poursaberi, Tahereh; Avanes, Armen; Sharghi, Hashem

    2006-01-01

    A new optical chemical sensor has been developed for the selective determination of copper(II) ions in aqueous solutions. The reversible sensing system was prepared by incorporating 1-hydroxy-2-(prop-2'-enyl)-4-(prop-2'-enyloxy)-9,10-anthraquinone (AQ) as a neutral Cu2+-selective fluoroionophore in the plasticized PVC membrane with potassium tetrakis(p-chlorophenyl borate) as an anionic additive. The response of the sensor is based on the fluorescence quenching of AQ by Cu2+ ions. At a pH 5.5, the proposed sensor displays a calibration response for Cu2+ over a wide concentration range of 1.0 x 10(-2) to 1.0 x 10(-6) M, with a relatively fast response of less than 40 s. In addition to high stability and reproducibility, the sensor shows a unique selectivity towards Cu2+ ion with respect to common co-existing cations. The proposed fluorescence optode was applied successfully to the determination of copper(II) in black tea samples.

  11. Estimating Security Betas Using Prior Information Based on Firm Fundamentals

    NARCIS (Netherlands)

    Cosemans, Mathijs; Frehen, Rik; Schotman, Peter; Bauer, Rob

    2016-01-01

    We propose a hybrid approach for estimating beta that shrinks rolling window estimates toward firm-specific priors motivated by economic theory. Our method yields superior forecasts of beta that have important practical implications. First, unlike standard rolling window betas, hybrid betas carry a

  12. Estimating security betas using prior information based on firm fundamentals

    NARCIS (Netherlands)

    Cosemans, Mathijs; Frehen, Rik; Schotman, Peter; Bauer, Rob

    2016-01-01

    We propose a hybrid approach for estimating beta that shrinks rolling window estimates towards firm-specific priors motivated by economic theory. Our method yields superior forecasts of beta that have important practical implications. First, hybrid betas carry a significant price of risk in the cros

  13. Dictionary learning based statistical interior reconstruction without a prior knowledge

    Science.gov (United States)

    Shi, Yongyi; Mou, Xuanqin

    2016-10-01

    Despite the significantly practical utilities of interior tomography, it still suffers from severe degradation of direct current (DC) shift artifact. Existing literature suggest to introducing prior information of object support (OS) constraint or the zeroth order image moment, i.e., the DC value into interior reconstruction to suppress the shift artifact, while the prior information is not always available in practice. Aimed at alleviating the artifacts without prior knowledge, in this paper, we reported an approach on the estimation of the object support which could be employed to estimate the zeroth order image moment, and hence facilitate the DC shift artifacts removal in interior reconstruction. Firstly, by assuming most of the reconstructed object consists of soft tissues that are equivalent to water, we reconstructed a virtual OS that is symmetrical about the interior region of interest (ROI) for the DC estimation. Hence the DC value can be estimated from the virtual reconstruction. Secondly, a statistical iterative reconstruction incorporated with the sparse representation in terms of learned dictionary and the constraint in terms of image DC value was adopted to solve the interior tomography. Experimental results demonstrate that the relative errors of the estimated zeroth order image moment are 4.7% and 7.6%, corresponding to the simulated data of a human thorax and the real data of a sheep lung, respectively. Reconstructed images with the constraint of the estimated DC value exhibit greatly superior image quality to that without DC value constraint.

  14. Electrochemical methods for the determination of the diffusion coefficient of ionophores and ionophore-ion complexes in plasticized PVC membranes.

    Science.gov (United States)

    Bodor, Sándor; Zook, Justin M; Lindner, Erno; Tóth, Klára; Gyurcsányi, Róbert E

    2008-05-01

    The diffusion coefficients of active components in ion-selective membranes have a decisive influence on the life-time and detection limit of the respective ion-selective electrodes, as well as influencing the rate of polarization and relaxation processes of electrically perturbed ion sensors. Therefore, the rational design of mass transport controlled ion-selective electrodes with sub-nanomolar detection limits requires reliable data on the diffusion coefficients. We have implemented electrochemical methods for the quantitative assessment of both the diffusion coefficients of free ionophores and ion-ionophore complexes. The diffusion coefficients of the pH-sensitive chromoionophore ETH 5294 and the calcium-selective ionophore ETH 5234 were determined in plasticized PVC membranes with different PVC to plasticizer ratios. The diffusion coefficient of the free chromoionophore determined by a chronoamperometric method was validated with optical methods for a variety of membrane compositions. The calcium-selective ionophore ETH 5234 was used as a model compound to assess the diffusion coefficient of the ion-ionophore complex calculated from the time required for the complexes to cross a freshly prepared membrane during potentiometric ion-breakthrough experiments. The difference between the diffusion coefficients of the free ionophore ETH 5234 and the ion-ionophore complex was found to be significant and correlated well with the geometry of the respective species.

  15. ROBUST RVM BASED ON SPIKE-SLAB PRIOR

    Institute of Scientific and Technical Information of China (English)

    Ding Xinghao; Mi Zengyuan; Huang Yue; Jin Wenbo

    2012-01-01

    Although Relevance Vector Machine (RVM) is the most popular algorithms in machine learning and computer vision,outliers in the training data make the estimation unreliable.In the paper,a robust RVM model under non-parametric Bayesian framework is proposed.We decompose the noise term in the RVM model into two components,a Gaussian noise term and a spiky noise term.Therefore the observed data is assumed represented as:y=Dw+s+e,where Dw is the relevance vector component,of which D is the kernel function matrix and w is the weight matrix,s is the spiky term and e is the Gaussian noise term.A spike-slab sparse prior is imposed on the weight vector w,which gives a more intuitive constraint on the sparsity than the Student's t-distribution described in the traditional RVM.For the spiky component s,a spike-slab sparse prior is also introduced to recognize outliers in the training data effectively.Several experiments demonstrate the better performance over the RVM regression.

  16. Micron dimensioned cavity array supported lipid bilayers for the electrochemical investigation of ionophore activity.

    Science.gov (United States)

    Maher, Sean; Basit, Hajra; Forster, Robert J; Keyes, Tia E

    2016-12-01

    Microcavity supported lipid bilayers, MSLBs, were applied to an electrochemical investigation of ionophore mediated ion transport. The arrays comprise of a 1cm(2) gold electrode imprinted with an ordered array of uniform spherical-cap pores of 2.8μm diameter prepared by gold electrodeposition through polystyrene templating spheres. The pores were pre-filled with aqueous buffer prior to Langmuir-Blodgett assembly of a 1,2-dioleoyl-sn-glycero-3-phosphocholine bilayer. Fluorescence lifetime correlation spectroscopy enabled by the micron dimensions of the pores permitted study of lipid diffusion across single apertures, yielding a diffusion coefficient of 12.58±1.28μm(2)s(-1) and anomalous exponent of 1.03±0.02, consistent with Brownian motion. From FLCS, the MSLBs were stable over 3days and electrochemical impedance spectroscopy of the membrane with and without ionic gradient over experimental windows of 6h showed excellent stability. Two ionophores were studied at the MSLBs; Valinomycin, a K(+) uniporter and Nigericin, a K(+)/H(+) antiporter. Ionophore reconstituted into the DOPC bilayer resulted in a decrease and increase in membrane resistance and capacitance respectively. Significant increases in Valinomycin and Nigericin activity were observed, reflected in large decreases in membrane resistance when K(+) was present in the contacting buffer and in the presence of H(+) ionic gradient across the membrane respectively.

  17. Trace Level Determination of Polyether Ionophores in Feed

    Directory of Open Access Journals (Sweden)

    Mervi Rokka

    2013-01-01

    Full Text Available A liquid chromatography-mass spectrometric method was developed and validated to determine six polyether ionophores (lasalocid sodium, monensin sodium, salinomycin sodium, narasin, maduramicin ammonium alpha, and semduramicin sodium in feed samples. The method developed was very straightforward, involving extraction with 84% acetonitrile of the coccidiostats from the feed samples and filtration of the raw extract prior to chromatographic analysis. Method validation included the determination of selectivity, linearity, specificity, repeatability, the limit of detection, limit of quantification, decision limit (CCα, detection capability (CCβ, and recovery. Feed samples from the Finnish national feed control programme and suspected carry-over samples from a feed manufacturer were analysed in parallel with an existing liquid chromatography method coupled with ultraviolet detection. All feed control samples were negative in LC-UV, but with the developed MS method, monensin, salinomycin, and narasin were detected at concentrations of <0.025–0.73 mg/kg, <0.025–0.027 mg/kg, and <0.025–1.6 mg/kg, respectively. In suspected carry-over samples after an output of 2.0 tonnes of unmedicated feed in the pelletizer line, the concentrations of monensin, salinomycin, and narasin varied from undetected to 16 mg/kg. In the mixer line, after 3.2 tonnes of unmedicated feed output, the concentrations of monensin, salinomycin, and narasin varied from undetected to 2.4 mg/kg.

  18. An objective prior that unifies objective Bayes and information-based inference

    CERN Document Server

    LaMont, Colin H

    2015-01-01

    There are three principle paradigms of statistical inference: (i) Bayesian, (ii) information-based and (iii) frequentist inference. We describe an objective prior (the weighting or $w$-prior) which unifies objective Bayes and information-based inference. The $w$-prior is chosen to make the marginal probability an unbiased estimator of the predictive performance of the model. This definition has several other natural interpretations. From the perspective of the information content of the prior, the $w$-prior is both uniformly and maximally uninformative. The $w$-prior can also be understood to result in a uniform density of distinguishable models in parameter space. Finally we demonstrate the the $w$-prior is equivalent to the Akaike Information Criterion (AIC) for regular models in the asymptotic limit. The $w$-prior appears to be generically applicable to statistical inference and is free of {\\it ad hoc} regularization. The mechanism for suppressing complexity is analogous to AIC: model complexity reduces mo...

  19. Extraction and detection of Ionophores in the Aquatic Environment

    DEFF Research Database (Denmark)

    Bak, Søren Alex; Hansen, Martin; Krogh, Kristine Andersen

    with resistance in the treatment of coccidiosis. Several reports have revealed that ionophores are emerging environmental contaminants in agricultural run-off waters, surface waters, sediments, and ground waters, due to their continuously increased and constant application as feed additives in modern livestock...... production (Dolliver et al. 2008; Hansen et al. 2009a and 2009b). Recent investigations has further reported that metabolites of certain veterinary drugs such as antibacterial agents (i.e. tetracyclines) and antiparacitics (i.e. ionophores) posses an environmental effects of similar level as their parent....... Coccidiosis is a major disease in poultry as well as in many other hosts. Ionophores are the most heavily applied sup-group of the two sub-groups of anticoccidial agents, because they also have antibacterial properties. After the ban of antibiotic growth promoters Ionophores are used extensively worldwide...

  20. Patient Preference for Dosing Frequency Based on Prior Biologic Experience.

    Science.gov (United States)

    Zhang, Mingliang; Carter, Chureen; Olson, William H; Johnson, Michael P; Brennem, Susan K; Lee, Seina; Farahi, Kamyar

    2017-03-01

    There is limited research exploring patient preferences regarding dosing frequency of biologic treatment of psoriasis. Patients with moderate-to-severe plaque psoriasis identified in a healthcare claims database completed a survey regarding experience with psoriasis treatments and preferred dosing frequency. Survey questions regarding preferences were posed in two ways: (1) by likelihood of choosing once per week or 2 weeks, or 12 weeks; and (2) by choosing one option among once every 1-2 or 3-4 weeks or 1-2 or 2-3 months. Data were analyzed by prior biologic history (biologic-experienced vs biologic-naïve, and with one or two specific biologics). Overall, 426 patients completed the survey: 163 biologic-naïve patients and 263 biologic-experienced patients (159 had some experience with etanercept, 105 with adalimumab, and 49 with ustekinumab). Among patients who indicated experience with one or two biologics, data were available for 219 (30 with three biologics and 14 did not specify which biologic experience). The majority of biologic-naïve (68.8%) and overall biologic-experienced (69.4%) patients indicated that they were very likely to choose the least frequent dosing option of once every 12 weeks (Table 1). In contrast, fewer biologic-naïve (9.1% and 16.7%) and biologic-experienced (22.5% and 25.3%) patients indicated that they were very likely to choose the 1-week and 2-week dosing interval options, respectively. In each cohort grouped by experience with specific biologics, among those with no experience with ustekinumab, the most chosen option was 1-2 weeks. The most frequently chosen option was every 2-3 months, among patients with any experience with ustekinumab, regardless of their experience with other biologics. The least frequent dosing interval was preferred among biologic naïve patients and patients who had any experience with ustekinumab. Dosing interval may influence the shared decision-making process for psoriasis treatment with biologics. J

  1. Wavelet-based denoising using local Laplace prior

    Science.gov (United States)

    Rabbani, Hossein; Vafadust, Mansur; Selesnick, Ivan

    2007-09-01

    Although wavelet-based image denoising is a powerful tool for image processing applications, relatively few publications have addressed so far wavelet-based video denoising. The main reason is that the standard 3-D data transforms do not provide useful representations with good energy compaction property, for most video data. For example, the multi-dimensional standard separable discrete wavelet transform (M-D DWT) mixes orientations and motions in its subbands, and produces the checkerboard artifacts. So, instead of M-D DWT, usually oriented transforms suchas multi-dimensional complex wavelet transform (M-D DCWT) are proposed for video processing. In this paper we use a Laplace distribution with local variance to model the statistical properties of noise-free wavelet coefficients. This distribution is able to simultaneously model the heavy-tailed and intrascale dependency properties of wavelets. Using this model, simple shrinkage functions are obtained employing maximum a posteriori (MAP) and minimum mean squared error (MMSE) estimators. These shrinkage functions are proposed for video denoising in DCWT domain. The simulation results shows that this simple denoising method has impressive performance visually and quantitatively.

  2. Extraction and detection of Ionophores in the Aquatic Environment

    DEFF Research Database (Denmark)

    Bak, Søren Alex; Hansen, Martin; Krogh, Kristine Andersen

    Anticoccidial agents or coccidiostatics are the only anti-bacterial substances still authorised as feed additives within the European Union (Vincent et al. 2011). Anticoccidial agents are used for the prevention of the disease coccidiosis, which is caused by a unicellular intestinal parasite....... Coccidiosis is a major disease in poultry as well as in many other hosts. Ionophores are the most heavily applied sup-group of the two sub-groups of anticoccidial agents, because they also have antibacterial properties. After the ban of antibiotic growth promoters Ionophores are used extensively worldwide...

  3. XID+ a new prior-based extraction tool for Herschel-SPIRE maps

    CERN Document Server

    Roehlly, Yannick

    2016-01-01

    We present XID+ a new generation of software for prior-based photometry extraction in the Herschel SPIRE maps. Based on a Bayesian framework, XID+ allows the inclusion of prior information and gives access to the full posterior probability distribution of fluxes. XID+ is developed within the Herschel Extragalactic Legacy Project (HELP) and is available at https://github.com/H-E-L-P/XID_plus.

  4. Uranyl salophenes as ionophores for phosphate-selective electrodes

    NARCIS (Netherlands)

    Wroblewski, Wojciech; Wojciechowski, Kamil; Dybko, Artur; Brzozka, Zbigniew; Egberink, Richard J.M.; Snellink-Ruel, Bianca H.M.; Reinhoudt, David N.

    2000-01-01

    Anion selectivities of poly(vinylchloride) (PVC) plasticized membranes containing uranyl salophene derivatives were presented. The influence of the membrane components (i.e. ionophore structure, dielectric constant and structure of plasticizer, the amount of incorporated ammonium salt) on its phosph

  5. Prior criminal charges and outcomes among individuals initiating office-based buprenorphine treatment

    OpenAIRE

    Harris, Elizabeth E; Jacapraro, Janet S; Rastegar, Darius A

    2013-01-01

    Background There is little data on the impact of prior criminal activity on the treatment of opioid dependence with office-based buprenorphine. The goal of this study was to investigate the association between prior criminal charges and treatment outcomes in a cohort of patients initiating buprenorphine treatment in a primary care practice. Methods This was a retrospective study of 252 consecutive patients with opioid dependence who were given at least one prescription for buprenorphine in a ...

  6. Efeito dos ionóforos e do balanço eletrolítico da dieta sobre o desempenho e a incidência de discondroplasia tibial em frangos de corte na fase inicial Effect of ionophores and acid-base balance on performance and incidence of tibial dyschondroplasia in 21-d old broiler chicks

    Directory of Open Access Journals (Sweden)

    José Rodrigo Galli Franco

    2004-02-01

    Full Text Available O objetivo do trabalho foi avaliar o efeito dos ionóforos e balanços eletrolíticos da dieta (BED no desempenho e na incidência de discondroplasia tibial (DT em frangos de corte de 1 a 21 dias de idade. Foram utilizados 1.600 pintos de corte, machos, "Cobb", distribuídos em um delineamento inteiramente casualizado, em esquema fatorial com três níveis de BED (230, 260 e 290 mEq/kg e dois ionóforos (lasalocida e salinomicina, mais dois tratamentos controle (230 e 260 mEq/kg, isentos de ionóforos, totalizando oito tratamentos, quatro repetições e 50 aves por unidade experimental. Verificou-se interação entre ionóforos e balanços para o peso aos 21 dias (P21 e consumo de ração (CR. Desdobrando essa interação, observou-se que, com a utilização de lasalocida, houve comportamento quadrático, em função do BED para o P21 e CR, sendo os valores mínimos para essas variáveis obtidos com 261 e 268 mEq/kg, respectivamente. Quando se utilizou salinomicina, não houve efeito do BED. A conversão alimentar (CA não sofreu influência dos ionóforos e do BED. Na comparação utilizando contrastes, constatou-se melhor P21 das aves com a adição de ionóforos às dietas, todavia, para o CR e CA não foram encontradas diferenças. Na comparação entre ionóforos, as aves que receberam salinomicina apresentaram peso superior àquelas que receberam lasalocida. O uso de salinomicina não mostrou efeito do BED sobre as áreas epifisárias, entretanto, com o uso do lasalocida, o incremento do BED proporcionou aumento linear dessas áreas. Concluiu-se que o uso de dietas com lasalocida reduziram o desempenho dos frangos, sendo que as aves que receberam salinomicina apresentaram maior P21 e não sofreram influência do BED na incidência de DT. No entanto, para lasalocida, houve aumento das áreas ósseas, que caracterizam a DT, com o aumento do BED.The objective of this research was to evaluate the effect of different ionophores and acid-base

  7. Infrared traffic image enhancement algorithm based on dark channel prior and gamma correction

    Science.gov (United States)

    Zheng, Lintao; Shi, Hengliang; Gu, Ming

    2017-07-01

    The infrared traffic image acquired by the intelligent traffic surveillance equipment has low contrast, little hierarchical differences in perceptions of image and the blurred vision effect. Therefore, infrared traffic image enhancement, being an indispensable key step, is applied to nearly all infrared imaging based traffic engineering applications. In this paper, we propose an infrared traffic image enhancement algorithm that is based on dark channel prior and gamma correction. In existing research dark channel prior, known as a famous image dehazing method, here is used to do infrared image enhancement for the first time. Initially, in the proposed algorithm, the original degraded infrared traffic image is transformed with dark channel prior as the initial enhanced result. A further adjustment based on the gamma curve is needed because initial enhanced result has lower brightness. Comprehensive validation experiments reveal that the proposed algorithm outperforms the current state-of-the-art algorithms.

  8. Salinomycin residues and their ionophoricity in pig tissues

    Energy Technology Data Exchange (ETDEWEB)

    Dimenna, G.P.; Lyon, F.S.; Creegan, J.A. (A.H. Robins Co., Richmond, VA (USA)); Wright, G.J. (Hill Top Pharmatest, Inc. Cincinnati, OH (USA)); Wilkes, L.C. (Analytical Development Corp., Colorado Springs, CO (USA)); Johnson, D.E.; Szymanski, T. (Colorado State Univ., Fort Collins (USA))

    1990-04-01

    The effect of pretreatment with medicated feed on ({sup 14}C) salinomycin residue levels in pig tissues was studied. Pigs were fed unmedicated feed or feed medicated with salinomycin at 41 ppm in the diet for 29 days and then dosed with ({sup 14}C)salinomycin for 8 days. Total drug residue levels were below quantifiable limits of detection of kidney, fat, and muscle but at the tolerance limit of 1,800 ppb for liver. In liver, pretreatment tended to lower total residue levels, and unchanged ({sup 14}C)salinomycin accounted for <1% of the total drug residue. Approximately 15-20% of the total drug residue in liver was bound. Ionophoric activity in extracts of livers from the treated pigs was minimal, and only 2 of the 12 treated samples had ionophoric activity more than twice that obtained from the controls.

  9. Helical peptide-polyamine and -polyether conjugates as synthetic ionophores.

    Science.gov (United States)

    Benincasa, Monica; Francescon, Marco; Fregonese, Massimo; Gennaro, Renato; Pengo, Paolo; Rossi, Paola; Scrimin, Paolo; Tecilla, Paolo

    2015-12-01

    Two new synthetic ionophores in which the hydrophobic portion is represented by a short helical Aib-peptide (Aib=α-amino-isobutyric acid) and the hydrophilic one is a poly-amino (1a) or a polyether (1b) chain have been prepared. The two conjugates show a high ionophoric activity in phospholipid membranes being able to efficiently dissipate a pH gradient and, in the case of 1b, to transport Na(+) across the membrane. Bioactivity evaluation of the two conjugates shows that 1a has a moderate antimicrobial activity against a broad spectrum of microorganisms and it is able to permeabilize the inner and the outer membrane of Escherichia coli cells.

  10. Improved compressed sensing-based cone-beam CT reconstruction using adaptive prior image constraints

    Science.gov (United States)

    Lee, Ho; Xing, Lei; Davidi, Ran; Li, Ruijiang; Qian, Jianguo; Lee, Rena

    2012-04-01

    Volumetric cone-beam CT (CBCT) images are acquired repeatedly during a course of radiation therapy and a natural question to ask is whether CBCT images obtained earlier in the process can be utilized as prior knowledge to reduce patient imaging dose in subsequent scans. The purpose of this work is to develop an adaptive prior image constrained compressed sensing (APICCS) method to solve this problem. Reconstructed images using full projections are taken on the first day of radiation therapy treatment and are used as prior images. The subsequent scans are acquired using a protocol of sparse projections. In the proposed APICCS algorithm, the prior images are utilized as an initial guess and are incorporated into the objective function in the compressed sensing (CS)-based iterative reconstruction process. Furthermore, the prior information is employed to detect any possible mismatched regions between the prior and current images for improved reconstruction. For this purpose, the prior images and the reconstructed images are classified into three anatomical regions: air, soft tissue and bone. Mismatched regions are identified by local differences of the corresponding groups in the two classified sets of images. A distance transformation is then introduced to convert the information into an adaptive voxel-dependent relaxation map. In constructing the relaxation map, the matched regions (unchanged anatomy) between the prior and current images are assigned with smaller weight values, which are translated into less influence on the CS iterative reconstruction process. On the other hand, the mismatched regions (changed anatomy) are associated with larger values and the regions are updated more by the new projection data, thus avoiding any possible adverse effects of prior images. The APICCS approach was systematically assessed by using patient data acquired under standard and low-dose protocols for qualitative and quantitative comparisons. The APICCS method provides an

  11. Prior Knowledge and Online Inquiry-Based Science Reading: Evidence from Eye Tracking

    Science.gov (United States)

    Ho, Hsin Ning Jessie; Tsai, Meng-Jung; Wang, Ching-Yeh; Tsai, Chin-Chung

    2014-01-01

    This study employed eye-tracking technology to examine how students with different levels of prior knowledge process text and data diagrams when reading a web-based scientific report. Students' visual behaviors were tracked and recorded when they read a report demonstrating the relationship between the greenhouse effect and global climate…

  12. Prior Knowledge and Online Inquiry-Based Science Reading: Evidence from Eye Tracking

    Science.gov (United States)

    Ho, Hsin Ning Jessie; Tsai, Meng-Jung; Wang, Ching-Yeh; Tsai, Chin-Chung

    2014-01-01

    This study employed eye-tracking technology to examine how students with different levels of prior knowledge process text and data diagrams when reading a web-based scientific report. Students' visual behaviors were tracked and recorded when they read a report demonstrating the relationship between the greenhouse effect and global climate…

  13. Multichannel Speech Enhancement Based on Generalized Gamma Prior Distribution with Its Online Adaptive Estimation

    Science.gov (United States)

    Dat, Tran Huy; Takeda, Kazuya; Itakura, Fumitada

    We present a multichannel speech enhancement method based on MAP speech spectral magnitude estimation using a generalized gamma model of speech prior distribution, where the model parameters are adapted from actual noisy speech in a frame-by-frame manner. The utilization of a more general prior distribution with its online adaptive estimation is shown to be effective for speech spectral estimation in noisy environments. Furthermore, the multi-channel information in terms of cross-channel statistics are shown to be useful to better adapt the prior distribution parameters to the actual observation, resulting in better performance of speech enhancement algorithm. We tested the proposed algorithm in an in-car speech database and obtained significant improvements of the speech recognition performance, particularly under non-stationary noise conditions such as music, air-conditioner and open window.

  14. Developing Training Image-Based Priors for Inversion of Subsurface Geophysical and Flow Data

    Science.gov (United States)

    Caers, J.

    2014-12-01

    Forecasting in subsurface formations, whether for groundwater, storage or oil & gas production, can rely on a wealth of geological information. Currently, most of this information remains underused in both the theory and practice of forecasting based on inverse models which heavily relies on spatial covariances and multi-Gaussian theory. By means of real field studies, I will provide an outline of how such geological information can be accounted through the construction and validation of a large set of training images and the generation of model realizations with MPS (multiple-point geostatistics). Often most critical in solving such inverse problems is the development of prior models that are later used for posterior sampling or stochastic search. I propose therefore a two-stage approach where the first stage consists of a validation of the training image-based prior with the geophysical and flow data. This stage will require only the generation of a few (100s) geological models and the forward modeling of the data response on these models. For geophysical data, the validation consists of comparing histograms of multi-scale wavelet transforms between the forward models and the field data. For flow data, the validation is based on a reduction of dimensionality of the forward response and the data using multi-dimensional scaling. The outcome of this validation is an estimate of the prior probability assigned to each training image, with several training images getting assigned zero probability (incompatible with field data). These prior probabilities are used in the second stage to actually invert for the data using stochastic search. In such stochastic search, I avoid parameterizing the model space and present methods that efficiently perform a direct search in the space of the validated training image-based prior model realizations.

  15. Lessons learned: the effect of prior technology use on Web-based interventions.

    Science.gov (United States)

    Carey, Joanne C; Wade, Shari L; Wolfe, Christopher R

    2008-04-01

    This study examined the role of regular prior technology use in treatment response to an online family problem-solving (OFPS) intervention and an Internet resource intervention (IRI) for pediatric traumatic brain injury (TBI). Participants were 150 individuals in 40 families of children with TBI randomly assigned to OFPS intervention or an IRI. All families received free computers and Internet access to TBI resources. OFPS families received Web-based sessions and therapist-guided synchronous videoconferences focusing on problem solving, communication skills, and behavior management. All participants completed measures of depression, anxiety, and computer usage. OFPS participants rated treatment satisfaction, therapeutic alliance, and Web site and technology comfort. With the OFPS intervention, depression and anxiety improved significantly more among technology using parents (n = 14) than nontechnology users (n = 6). Technology users reported increasing comfort with technology over time, and this change was predictive of depression at followup. Satisfaction and ease-of-use ratings did not differ by technology usage. Lack of regular prior home computer usage and nonadherence were predictive of anxiety at followup. The IRI was not globally effective. However, controlling for prior depression, age, and technology at work, there was a significant effect of technology at home for depression. Families with technology experience at home (n = 11) reported significantly greater improvements in depression than families without prior technology experience at home (n = 8). Although Web-based OFPS was effective in improving caregiver functioning, individuals with limited computer experience may benefit less from an online intervention due to increased nonadherence.

  16. An image reconstruction algorithm of EIT based on pulmonary prior information

    Institute of Scientific and Technical Information of China (English)

    Huaxiang WANG; Li HU; ling WANG; Lu LI

    2009-01-01

    Using a CT scan of the pulmonary tissue, a human pulmonary model is established combined with the structure property of the human lung tissue using the software COMSOL. Combined with the conductivity contribution information of the human tissue and organ,an image reconstruction method of electrical impedance tomography based on pulmonary prior information is proposed using the conjugate gradient method. Simulation results show that the uniformity index of sensitivity distribution of the pulmonary model is 15.568, which is significantly reduced compared with 34.218 based on the round field. The proposed algorithm improves the uniformity of the sensing field, the image resolution of the conductivity distribution of pulmonary tissue and the quality of the reconstruction image based on pulmonary prior information.

  17. Gene function classification using Bayesian models with hierarchy-based priors

    Directory of Open Access Journals (Sweden)

    Neal Radford M

    2006-10-01

    Full Text Available Abstract Background We investigate whether annotation of gene function can be improved using a classification scheme that is aware that functional classes are organized in a hierarchy. The classifiers look at phylogenic descriptors, sequence based attributes, and predicted secondary structure. We discuss three Bayesian models and compare their performance in terms of predictive accuracy. These models are the ordinary multinomial logit (MNL model, a hierarchical model based on a set of nested MNL models, and an MNL model with a prior that introduces correlations between the parameters for classes that are nearby in the hierarchy. We also provide a new scheme for combining different sources of information. We use these models to predict the functional class of Open Reading Frames (ORFs from the E. coli genome. Results The results from all three models show substantial improvement over previous methods, which were based on the C5 decision tree algorithm. The MNL model using a prior based on the hierarchy outperforms both the non-hierarchical MNL model and the nested MNL model. In contrast to previous attempts at combining the three sources of information in this dataset, our new approach to combining data sources produces a higher accuracy rate than applying our models to each data source alone. Conclusion Together, these results show that gene function can be predicted with higher accuracy than previously achieved, using Bayesian models that incorporate suitable prior information.

  18. A comparative study of four 20-membered N_2S_4-crown ethers as ionophores for polymeric membrane silver selective electrodes

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Four 20-membered N_2S_4-monoazathiacrown ethers have been synthesized and explored as neutral ionophores for Ag~+-selective electrodes.Potentiometric responses reveal that the flexibility of the ligands has great effect on the selectivity and sensitivity to Ag~+ ions.The electrode based on ionophore 9,10,20,25-tetrahydro-5H,12H-tribenzo[b,n,r][1,7,10,16,4,13]tetrathiadiaza cycloicosine 6,13-(7H,14H)-dione(C) with 2-nitrophenyl octyl ether(o-NPOE) as solvent in a poly(vinyl chloride)(PVC) membrane matrix ...

  19. Development and validation of an SPE methodology combined with LC-MS/MS for the determination of four ionophores in aqueous environmental matrices

    DEFF Research Database (Denmark)

    Bak, Søren Alex; Hansen, Martin; Krogh, Kristine Andersen;

    2013-01-01

    A multi-residue analytical methodology has been established for the determination of the four ionophores: lasalocid, monensin, salinomycin and narasin in aqueous environmental matrices, using nigericin as internal standard. The samples were filtrated prior to solid phase extraction. All compounds...... water bodies with LOQs for the entire methodology being 40, 49, 67, and 14 ng/L for lasalocid, monensin, salinomycin, and narasin, respectively....

  20. Anticancer Activity of Polyether Ionophore-Salinomycin.

    Science.gov (United States)

    Antoszczak, Michał; Huczyński, Adam

    2015-01-01

    Since the discovery of unusual anti-tumor activity of natural polyether antibiotic - Salinomycin, this compound, along with its derivatives, has been intensively studied against different human cancer cells, both in vivo and in vitro. Salinomycin has shown strong inhibition activity against the proliferation process of many different cancer cells, including multi-drug resistance (MDR) cancer cells, as well as cancer stem cells (CSCs), i.e. leukemic stem cells, colon carcinoma stem cells, prostate cancer stem cells and many others. Additionally, the application of Salinomycin has been proved to enhance the anti-cancer effect of radio- and chemotherapy. Preliminary clinical studies have shown tumor regression and only transient acute side effects after application of Salinomycin. Up to now, major efforts have been devoted to elucidate the biological mechanisms of anti-tumor activity of Salinomycin and it is expected that the results may provide new therapeutic strategies based on biological modulation of Salinomycin activity. This review is focused on and describes the possible role of Salinomycin in cancer therapy and gives an overview of its properties.

  1. Criminal charges prior to and after initiation of office-based buprenorphine treatment

    Directory of Open Access Journals (Sweden)

    Harris Elizabeth E

    2012-03-01

    Full Text Available Abstract Background There is little data on the impact of office-based buprenorphine therapy on criminal activity. The goal of this study was to determine the impact of primary care clinic-based buprenorphine maintenance therapy on rates of criminal charges and the factors associated with criminal charges in the 2 years after initiation of treatment. Methods We collected demographic and outcome data on 252 patients who were given at least one prescription for buprenorphine. We searched a public database of criminal charges and recorded criminal charges prior to and after enrollment. We compared the total number of criminal cases and drug cases 2 years before versus 2 years after initiation of treatment. Results There was at least one criminal charge made against 38% of the subjects in the 2 years after initiation of treatment; these subjects were more likely to have used heroin, to have injected drugs, to have had any prior criminal charges, and recent criminal charges. There was no significant difference in the number of subjects with any criminal charge or a drug charge before and after initiation of treatment. Likewise, the mean number of all cases and drug cases was not significantly different between the two periods. However, among those who were opioid-negative for 6 or more months in the first year of treatment, there was a significant decline in criminal cases. On multivariable analysis, having recent criminal charges was significantly associated with criminal charges after initiation of treatment (adjusted odds ratio 3.92; subjects who were on opioid maintenance treatment prior to enrollment were significantly less likely to have subsequent criminal charges (adjusted odds ratio 0.52. Conclusions Among subjects with prior criminal charges, initiation of office-based buprenorphine treatment did not appear to have a significant impact on subsequent criminal charges.

  2. Vertebral segmentation using contourlet-based salient point matching and localized multiscale shape prior

    Science.gov (United States)

    Zewail, R.; Elsafi, A.; Durdle, N.

    2009-02-01

    Medical experts often examine hundreds of spine x-rays to determine existence of diseases like osteoarthritis, osteoporoses, and osteophites. Accurate vertebrae segmentation plays a great role in the proper assessment of various vertebral abnormalities. Manual segmentation methods are both time consuming and non-reproducible, hence, developing efficient computer-assisted segmentation methods has been a long standing goal. Over the past decade, segmentation methods that utilize statistical models of shape and appearance have drawn much interest within the medical imaging community. However, despite being a promising approach, they are always faced with a number of challenges such as: poor image quality, and the ability to generalize well to unseen vertebral deformities. This paper presents a novel vertebral segmentation method using Contourlet-based salient point matching and a localized multi-scale shape prior. We employ a multi-scale directional analysis tool, namely contourlets, to build local appearance profiles at salient points of the vertebra's body. The contourlet-based local appearance model is used to detect the vertebral bodies in the test x-ray image. A novel localized multi-scale shape prior is used to drive the segmentation process. Within a best-basis selection framework, the proposed shape prior benefits from the multi-scale nature of wavelet packets, and the capability of ICA to capture hidden independent modes of variations. Experiments were conducted using a set of 100 digital x-ray images of lumbar spines. The contourlet-based appearance profiles and the localized multi-scale shape prior were constructed using a training subset of images, and then matched to unseen images. Promising results were obtained compared to related work in the literature with an average segmentation error of 1.1997 mm.

  3. Self-similar prior and wavelet bases for hidden incompressible turbulent motion

    CERN Document Server

    Héas, Patrick; Kadri-Harouna, Souleymane

    2013-01-01

    This work is concerned with the ill-posed inverse problem of estimating turbulent flows from the observation of an image sequence. From a Bayesian perspective, a divergence-free isotropic fractional Brownian motion (fBm) is chosen as a prior model for instantaneous turbulent velocity fields. This self-similar prior characterizes accurately second-order statistics of velocity fields in incompressible isotropic turbulence. Nevertheless, the associated maximum a posteriori involves a fractional Laplacian operator which is delicate to implement in practice. To deal with this issue, we propose to decompose the divergent-free fBm on well-chosen wavelet bases. As a first alternative, we propose to design wavelets as whitening filters. We show that these filters are fractional Laplacian wavelets composed with the Leray projector. As a second alternative, we use a divergence-free wavelet basis, which takes implicitly into account the incompressibility constraint arising from physics. Although the latter decomposition ...

  4. Inhibition of membrane lipid peroxidation by a radical scavenging mechanism: a novel function for hydroxyl-containing ionophores.

    Science.gov (United States)

    Grijalba, M T; Andrade, P B; Meinicke, A R; Castilho, R F; Vercesi, A E; Schreier, S

    1998-03-01

    of radicals derived from piperazine-based buffers, demonstrating their property as radical scavengers. Both Fe2+-citrate and ABAP promote a much more pronounced decrease of LAS fluorescence in PC/CL liposomes than in dimyristoyl phosphatidylcholine (DMPC, saturated phospholipid)-DCP liposomes, indicating that the ionophore also scavenges lipid peroxyl radicals. A slow decrease of fluorescence is observed in the latter system, for all lipid compositions in sucrose medium, and in the absence of membranes, indicating that the primary radicals stemming from both inductors also attack the ionophore. Altogether, the data lead to the conclusion that the membrane-incorporated cation complexes of NIG, LAS and MON inhibit lipid peroxidation by blocking initiation and propagation reactions in the lipid phase via a free radical scavenging mechanism, very likely due to the presence of alcoholic hydroxyl groups in all three molecules and to the attack of the aromatic moiety of LAS.

  5. Evaluation of ionophore sensitivity of Eimeria acervulina and Eimeria maxima isolated from the Algerian to Jijel province poultry farms.

    Science.gov (United States)

    Djemai, Samir; Mekroud, Abdeslam; Jenkins, Mark C

    2016-07-15

    The present study represents the first description of ionophore resistance in recovered from commercial Algerian (Jijel-Algeria) broiler farms. Microscopy and intervening transcribed sequence 1 PCR (ITS1 PCR) revealed only 2 Eimeria species present in litter from these farms- namely Eimeria acervulina and Eimeria maxima. A pool of these isolates were evaluated in broiler chickens (Cobb 500) for sensitivity to 5 anticoccidial compounds-diclazuril (1ppm), lasalocid (125ppm), monensin (125ppm), narasin (70ppm) and salinomycin (60ppm). As indicated by anticoccidial sensitivity profiles based on lesion scores and anticoccidial index (ACI), complete resistance to monensin and narasin, partial resistance to salinomycin and lasalocid, and complete sensitivity to diclazuril was observed. While lack of sensitivity to monensin is not surprising given its use for years as the sole anticoccidial compound, the resistance to monoether (narasin) and polyether (lasalocid) ionophores suggests that cross-resistance has developed in a segment of the Eimeria population. The fairly uniform Eimeria species composition among all poultry farms suggests that E. acervulina and E. maxima more rapidly develop resistance to ionophore drugs.

  6. Dark channel prior based blurred image restoration method using total variation and morphology

    Institute of Scientific and Technical Information of China (English)

    Yibing Li; Qiang Fu; Fang Ye; Hayaru Shouno

    2015-01-01

    The blurred image restoration method can dramatical y highlight the image details and enhance the global contrast, which is of benefit to improvement of the visual effect during practical ap-plications. This paper is based on the dark channel prior principle and aims at the prior information absent blurred image degradation situation. A lot of improvements have been made to estimate the transmission map of blurred images. Since the dark channel prior principle can effectively restore the blurred image at the cost of a large amount of computation, the total variation (TV) and image morphology transform (specifical y top-hat transform and bottom-hat transform) have been introduced into the improved method. Compared with original transmission map estimation methods, the proposed method features both simplicity and accuracy. The es-timated transmission map together with the element can restore the image. Simulation results show that this method could inhibit the il-posed problem during image restoration, meanwhile it can greatly improve the image quality and definition.

  7. Ligand placement based on prior structures: the guided ligand-replacement method

    Energy Technology Data Exchange (ETDEWEB)

    Klei, Herbert E. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Bristol-Myers Squibb, Princeton, NJ 08543-4000 (United States); Moriarty, Nigel W., E-mail: nwmoriarty@lbl.gov; Echols, Nathaniel [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Terwilliger, Thomas C. [Los Alamos National Laboratory, Los Alamos, NM 87545-0001 (United States); Baldwin, Eric T. [Bristol-Myers Squibb, Princeton, NJ 08543-4000 (United States); Natural Discovery LLC, Princeton, NJ 08542-0096 (United States); Pokross, Matt; Posy, Shana [Bristol-Myers Squibb, Princeton, NJ 08543-4000 (United States); Adams, Paul D. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); University of California at Berkeley, Berkeley, CA 94720-1762 (United States)

    2014-01-01

    A new module, Guided Ligand Replacement (GLR), has been developed in Phenix to increase the ease and success rate of ligand placement when prior protein-ligand complexes are available. The process of iterative structure-based drug design involves the X-ray crystal structure determination of upwards of 100 ligands with the same general scaffold (i.e. chemotype) complexed with very similar, if not identical, protein targets. In conjunction with insights from computational models and assays, this collection of crystal structures is analyzed to improve potency, to achieve better selectivity and to reduce liabilities such as absorption, distribution, metabolism, excretion and toxicology. Current methods for modeling ligands into electron-density maps typically do not utilize information on how similar ligands bound in related structures. Even if the electron density is of sufficient quality and resolution to allow de novo placement, the process can take considerable time as the size, complexity and torsional degrees of freedom of the ligands increase. A new module, Guided Ligand Replacement (GLR), was developed in Phenix to increase the ease and success rate of ligand placement when prior protein–ligand complexes are available. At the heart of GLR is an algorithm based on graph theory that associates atoms in the target ligand with analogous atoms in the reference ligand. Based on this correspondence, a set of coordinates is generated for the target ligand. GLR is especially useful in two situations: (i) modeling a series of large, flexible, complicated or macrocyclic ligands in successive structures and (ii) modeling ligands as part of a refinement pipeline that can automatically select a reference structure. Even in those cases for which no reference structure is available, if there are multiple copies of the bound ligand per asymmetric unit GLR offers an efficient way to complete the model after the first ligand has been placed. In all of these applications, GLR

  8. Dissecting complex transcriptional responses using pathway-level scores based on prior information

    Directory of Open Access Journals (Sweden)

    Ward Lucas D

    2007-09-01

    Full Text Available Abstract Background The genomewide pattern of changes in mRNA expression measured using DNA microarrays is typically a complex superposition of the response of multiple regulatory pathways to changes in the environment of the cells. The use of prior information, either about the function of the protein encoded by each gene, or about the physical interactions between regulatory factors and the sequences controlling its expression, has emerged as a powerful approach for dissecting complex transcriptional responses. Results We review two different approaches for combining the noisy expression levels of multiple individual genes into robust pathway-level differential expression scores. The first is based on a comparison between the distribution of expression levels of genes within a predefined gene set and those of all other genes in the genome. The second starts from an estimate of the strength of genomewide regulatory network connectivities based on sequence information or direct measurements of protein-DNA interactions, and uses regression analysis to estimate the activity of gene regulatory pathways. The statistical methods used are explained in detail. Conclusion By avoiding the thresholding of individual genes, pathway-level analysis of differential expression based on prior information can be considerably more sensitive to subtle changes in gene expression than gene-level analysis. The methods are technically straightforward and yield results that are easily interpretable, both biologically and statistically.

  9. Factors affecting learning of vector math from computer-based practice: Feedback complexity and prior knowledge

    Science.gov (United States)

    Heckler, Andrew F.; Mikula, Brendon D.

    2016-06-01

    In experiments including over 450 university-level students, we studied the effectiveness and time efficiency of several levels of feedback complexity in simple, computer-based training utilizing static question sequences. The learning domain was simple vector math, an essential skill in introductory physics. In a unique full factorial design, we studied the relative effects of "knowledge of correct response" feedback and "elaborated feedback" (i.e., a general explanation) both separately and together. A number of other factors were analyzed, including training time, physics course grade, prior knowledge of vector math, and student beliefs about both their proficiency in and the importance of vector math. We hypothesize a simple model predicting how the effectiveness of feedback depends on prior knowledge, and the results confirm this knowledge-by-treatment interaction. Most notably, elaborated feedback is the most effective feedback, especially for students with low prior knowledge and low course grade. In contrast, knowledge of correct response feedback was less effective for low-performing students, and including both kinds of feedback did not significantly improve performance compared to elaborated feedback alone. Further, while elaborated feedback resulted in higher scores, the learning rate was at best only marginally higher because the training time was slightly longer. Training time data revealed that students spent significantly more time on the elaborated feedback after answering a training question incorrectly. Finally, we found that training improved student self-reported proficiency and that belief in the importance of the learned domain improved the effectiveness of training. Overall, we found that computer based training with static question sequences and immediate elaborated feedback in the form of simple and general explanations can be an effective way to improve student performance on a physics essential skill, especially for less prepared and low

  10. Extraction and detection of Ionophores in the Aquatic Environment

    DEFF Research Database (Denmark)

    Bak, Søren Alex; Hansen, Martin; Krogh, Kristine Andersen;

    . 2002; Hansen et al. 2009c). The focus of the present study is on the recent advances of a new analytical method for sampling, extraction and detection of ionophores in liquid matrices. The hyphenated method consists of an integrated clean-up with solid phase extraction followed by high......-performance liquid chromatography tandem in space mass spectrometry. Halling-Sørensen B, Sengelov G, Tjørnelund J (2002) Arch Environ Contam Toxicol, 42: 3, pp. 263-271 Dolliver H, Gupta S (2008) J. Environ. Qual. 37: 2 pp. 1227-1237. Hansen M, Björklund E, Krogh KA, Halling-Sørensen B (2009a) TrAC 28:5 pp521...

  11. Accreditation of Prior Experiential Learning as a Catalyst for Lifelong Learning: Analysis and Proposals Based on French Experiments

    Science.gov (United States)

    Sanseau, Pierre-Yves; Ansart, Sandrine

    2013-01-01

    In this paper, the researchers analyse how lifelong learning can be enriched and develop a different perspective based on the experiment involving the accreditation of prior experiential learning (APEL) conducted in France at the university level. The French system for the accreditation of prior experiential learning, called Validation des Acquis…

  12. Accreditation of Prior Experiential Learning as a Catalyst for Lifelong Learning: Analysis and Proposals Based on French Experiments

    Science.gov (United States)

    Sanseau, Pierre-Yves; Ansart, Sandrine

    2013-01-01

    In this paper, the researchers analyse how lifelong learning can be enriched and develop a different perspective based on the experiment involving the accreditation of prior experiential learning (APEL) conducted in France at the university level. The French system for the accreditation of prior experiential learning, called Validation des Acquis…

  13. A new combined prior based reconstruction method for compressed sensing in 3D ultrasound imaging

    Science.gov (United States)

    Uddin, Muhammad S.; Islam, Rafiqul; Tahtali, Murat; Lambert, Andrew J.; Pickering, Mark R.

    2015-03-01

    Ultrasound (US) imaging is one of the most popular medical imaging modalities, with 3D US imaging gaining popularity recently due to its considerable advantages over 2D US imaging. However, as it is limited by long acquisition times and the huge amount of data processing it requires, methods for reducing these factors have attracted considerable research interest. Compressed sensing (CS) is one of the best candidates for accelerating the acquisition rate and reducing the data processing time without degrading image quality. However, CS is prone to introduce noise-like artefacts due to random under-sampling. To address this issue, we propose a combined prior-based reconstruction method for 3D US imaging. A Laplacian mixture model (LMM) constraint in the wavelet domain is combined with a total variation (TV) constraint to create a new regularization regularization prior. An experimental evaluation conducted to validate our method using synthetic 3D US images shows that it performs better than other approaches in terms of both qualitative and quantitative measures.

  14. A pseudo-discrete algebraic reconstruction technique (PDART) prior image-based suppression of high density artifacts in computed tomography

    Science.gov (United States)

    Pua, Rizza; Park, Miran; Wi, Sunhee; Cho, Seungryong

    2016-12-01

    We propose a hybrid metal artifact reduction (MAR) approach for computed tomography (CT) that is computationally more efficient than a fully iterative reconstruction method, but at the same time achieves superior image quality to the interpolation-based in-painting techniques. Our proposed MAR method, an image-based artifact subtraction approach, utilizes an intermediate prior image reconstructed via PDART to recover the background information underlying the high density objects. For comparison, prior images generated by total-variation minimization (TVM) algorithm, as a realization of fully iterative approach, were also utilized as intermediate images. From the simulation and real experimental results, it has been shown that PDART drastically accelerates the reconstruction to an acceptable quality of prior images. Incorporating PDART-reconstructed prior images in the proposed MAR scheme achieved higher quality images than those by a conventional in-painting method. Furthermore, the results were comparable to the fully iterative MAR that uses high-quality TVM prior images.

  15. Alum and Rainfall Effects on Ionophores in Runoff from Surface-Applied Broiler Litter.

    Science.gov (United States)

    Doydora, Sarah A; Franklin, Dorcas; Sun, Peizhe; Cabrera, Miguel; Thompson, Aaron; Love-Myers, Kimberly; Rema, John; Calvert, Vaughn; Pavlostathis, Spyros G; Huang, Ching-Hua

    2015-09-01

    Polyether ionophores, monensin, and salinomycin are commonly used as antiparasitic drugs in broiler production and may be present in broiler litter (bird excreta plus bedding material). Long-term application of broiler litter to pastures may lead to ionophore contamination of surface waters. Because polyether ionophores break down at low pH, we hypothesized that decreasing litter pH with an acidic material such as aluminum sulfate (alum) would reduce ionophore losses to runoff (i.e., monensin and salinomycin concentrations, loads, or amounts lost). We quantified ionophore loss to runoff in response to (i) addition of alum to broiler litter and (ii) length of time between litter application and the first simulated rainfall event. The factorial experiment consisted of unamended (∼pH 9) vs. alum-amended litters (∼pH 6), each combined with simulated rainfall at 0, 2, or 4 wk after litter application. Runoff from alum-amended broiler litter had 33% lower monensin concentration ( runoff from unamended broiler litter when averaged across all events of rainfall. Ionophore losses to runoff were also less when rainfall was delayed for 2 or 4 wk after litter application relative to applying rainfall immediately after litter application. While the weather is difficult to predict, our data suggest that ionophore losses in runoff can be reduced if broiler litter applications are made to maximize dry time after application.

  16. Optical flow based deformable volume registration using a novel second-order regularization prior

    Science.gov (United States)

    Grbić, Saša; Urschler, Martin; Pock, Thomas; Bischof, Horst

    2010-03-01

    Nonlinear image registration is an initial step for a large number of medical image analysis applications. Optical flow based intensity registration is often used for dealing with intra-modality applications involving motion differences. In this work we present an energy functional which uses a novel, second-order regularization prior of the displacement field. Compared to other methods our scheme is robust to non-Gaussian noise and does not penalize locally affine deformation fields in homogeneous areas. We propose an efficient and stable numerical scheme to find the minimizer of the presented energy. We implemented our algorithm using modern consumer graphics processing units and thereby increased the execution performance dramatically. We further show experimental evaluations on clinical CT thorax data sets at different breathing states and on dynamic 4D CT cardiac data sets.

  17. A Unified Spatiotemporal Prior based on Geodesic Distance for Video Object Segmentation.

    Science.gov (United States)

    Wang, Wenguan; Shen, Jianbing; Yang, Ruigang; Porikli, Fatih

    2017-01-31

    Video saliency, aiming for estimation of a single dominant object in a sequence, offers strong object-level cues for unsupervised video object segmentation. In this paper, we present a geodesic distance based technique that provides reliable and temporally consistent saliency measurement of superpixels as a prior for pixel-wise labeling. Using undirected intra-frame and inter-frame graphs constructed from spatiotemporal edges or appearance and motion, and a skeleton abstraction step to further enhance saliency estimates, our method formulates the pixel-wise segmentation task as an energy minimization problem on a function that consists of unary terms of global foreground and background models, dynamic location models, and pairwise terms of label smoothness potentials. We perform extensive quantitative and qualitative experiments on benchmark datasets. Our method achieves superior performance in comparison to the current state-of-the-art in terms of accuracy and speed.

  18. Design of a Selective and Sensitive PVC-Membrane Potentiometric Sensor for Strontium Ion Based on 1,10-Diaza-5,6-benzo-4,7-dioxacyclohexadecane-2,9-dione as a Neutral Ionophore

    Science.gov (United States)

    Shamsipur, Mojtaba; Kazemi, Sayed Yahya; Sharghi, Hashem

    2007-01-01

    A novel PVC membrane sensor for the Sr2+ ion based on 1,10-diaza-5,6-benzo-4,7-dioxacyclohexadecane-2,9-dione has been prepared. The sensor possesses a Nernstian slope of 30.0 ± 0.6 mV decade-1 over a wide linear concentration range of 1.6 × 10-6-3.0 ×10-3 M with a detection limit of 6.3 ×10-7 M. It has a fast response time of <15 s and can be used for at least two months without any considerable divergence in potential. The potentiometric response is independent of the pH of test solution in the pH range 4.3-9.4. The proposed electrode shows good selectivities over a variety of alkali, alkaline earth, and transition metal ions.

  19. A generalized Fourier penalty in prior-image-based reconstruction for cross-platform imaging

    Science.gov (United States)

    Pourmorteza, A.; Siewerdsen, J. H.; Stayman, J. W.

    2016-03-01

    Sequential CT studies present an excellent opportunity to apply prior-image-based reconstruction (PIBR) methods that leverage high-fidelity prior imaging studies to improve image quality and/or reduce x-ray exposure in subsequent studies. One major obstacle in using PIBR is that the initial and subsequent studies are often performed on different scanners (e.g. diagnostic CT followed by CBCT for interventional guidance); this results in mismatch in attenuation values due to hardware and software differences. While improved artifact correction techniques can potentially mitigate such differences, the correction is often incomplete. Here, we present an alternate strategy where the PIBR itself is used to mitigate these differences. We define a new penalty for the previously introduced PIBR called Reconstruction of Difference (RoD). RoD differs from many other PIBRs in that it reconstructs only changes in the anatomy (vs. reconstructing the current anatomy). Direct regularization of the difference image in RoD provides an opportunity to selectively penalize spatial frequencies of the difference image (e.g. low frequency differences associated with attenuation offsets and shading artifacts) without interfering with the variations in unchanged background image. We leverage this flexibility and introduce a novel regularization strategy using a generalized Fourier penalty within the RoD framework and develop the modified reconstruction algorithm. We evaluate the performance of the new approach in both simulation studies and in physical CBCT test-bench data. We find that generalized Fourier penalty can be highly effective in reducing low-frequency x-ray artifacts through selective suppression of spatial frequencies in the reconstructed difference image.

  20. Network reconstruction based on proteomic data and prior knowledge of protein connectivity using graph theory.

    Science.gov (United States)

    Stavrakas, Vassilis; Melas, Ioannis N; Sakellaropoulos, Theodore; Alexopoulos, Leonidas G

    2015-01-01

    Modeling of signal transduction pathways is instrumental for understanding cells' function. People have been tackling modeling of signaling pathways in order to accurately represent the signaling events inside cells' biochemical microenvironment in a way meaningful for scientists in a biological field. In this article, we propose a method to interrogate such pathways in order to produce cell-specific signaling models. We integrate available prior knowledge of protein connectivity, in a form of a Prior Knowledge Network (PKN) with phosphoproteomic data to construct predictive models of the protein connectivity of the interrogated cell type. Several computational methodologies focusing on pathways' logic modeling using optimization formulations or machine learning algorithms have been published on this front over the past few years. Here, we introduce a light and fast approach that uses a breadth-first traversal of the graph to identify the shortest pathways and score proteins in the PKN, fitting the dependencies extracted from the experimental design. The pathways are then combined through a heuristic formulation to produce a final topology handling inconsistencies between the PKN and the experimental scenarios. Our results show that the algorithm we developed is efficient and accurate for the construction of medium and large scale signaling networks. We demonstrate the applicability of the proposed approach by interrogating a manually curated interaction graph model of EGF/TNFA stimulation against made up experimental data. To avoid the possibility of erroneous predictions, we performed a cross-validation analysis. Finally, we validate that the introduced approach generates predictive topologies, comparable to the ILP formulation. Overall, an efficient approach based on graph theory is presented herein to interrogate protein-protein interaction networks and to provide meaningful biological insights.

  1. Network reconstruction based on proteomic data and prior knowledge of protein connectivity using graph theory.

    Directory of Open Access Journals (Sweden)

    Vassilis Stavrakas

    Full Text Available Modeling of signal transduction pathways is instrumental for understanding cells' function. People have been tackling modeling of signaling pathways in order to accurately represent the signaling events inside cells' biochemical microenvironment in a way meaningful for scientists in a biological field. In this article, we propose a method to interrogate such pathways in order to produce cell-specific signaling models. We integrate available prior knowledge of protein connectivity, in a form of a Prior Knowledge Network (PKN with phosphoproteomic data to construct predictive models of the protein connectivity of the interrogated cell type. Several computational methodologies focusing on pathways' logic modeling using optimization formulations or machine learning algorithms have been published on this front over the past few years. Here, we introduce a light and fast approach that uses a breadth-first traversal of the graph to identify the shortest pathways and score proteins in the PKN, fitting the dependencies extracted from the experimental design. The pathways are then combined through a heuristic formulation to produce a final topology handling inconsistencies between the PKN and the experimental scenarios. Our results show that the algorithm we developed is efficient and accurate for the construction of medium and large scale signaling networks. We demonstrate the applicability of the proposed approach by interrogating a manually curated interaction graph model of EGF/TNFA stimulation against made up experimental data. To avoid the possibility of erroneous predictions, we performed a cross-validation analysis. Finally, we validate that the introduced approach generates predictive topologies, comparable to the ILP formulation. Overall, an efficient approach based on graph theory is presented herein to interrogate protein-protein interaction networks and to provide meaningful biological insights.

  2. Design of a Selective and Sensitive PVC-Membrane Potentiometric Sensor for Strontium Ion Based on 1,10-Diaza-5,6-benzo-4,7-dioxacyclohexadecane-2,9-dioneas a Neutral Ionophore

    Directory of Open Access Journals (Sweden)

    Hashem Sharghi

    2007-04-01

    Full Text Available A novel PVC membrane sensor for the Sr2+ ion based on 1,10-diaza-5,6-benzo-4,7- dioxacyclohexadecane-2,9-dione has been prepared. The sensor possesses a Nernstian slope of 30.0 ± 0.6 mV decade-1 over a wide linear concentration range of 1.6 × 10-6-3.0 ×10-3 M with a detection limit of 6.3 ×10-7 M. It has a fast response time of less than 15 s and can be used for at least two months without any considerable divergence in potential. The potentiometric response is independent of the pH of test solution in the pH range 4.3-9.4. The proposed electrode shows good selectivities over a variety of alkali, alkaline earth, and transition metal ions.

  3. Do Online Comments Influence the Public's Attitudes Toward an Organization? Effects of Online Comments Based on Individuals' Prior Attitudes.

    Science.gov (United States)

    Sung, Kang Hoon; Lee, Moon J

    2015-01-01

    The authors investigated the effects of reading different types of online comments about a company on people's attitude change based on individual's prior attitude toward the company. Based on Social Judgment Theory, several hypotheses were tested. The results showed that the effects of online comments interact with individuals' prior attitudes toward a corporation. People with a strong negative attitude toward a corporation were less influenced by other's online comments than people with a neutral attitude in general. However, people with a prior negative attitude were more affected by refutational two-sided comments than one-sided comments. The results suggest that the effects of user generated content should be studied in a holistic manner, not only by investigating the effects of online content itself, but also by examining how others' responses to the content shape or change individuals' attitudes based on their prior attitudes.

  4. A Prior-based Transfer Learning Method for the Phishing Detection

    Directory of Open Access Journals (Sweden)

    Jianyi Zhang

    2012-08-01

    Full Text Available In this paper, we introduce a prior-based transfer  learning method for our statistical machine learning  classifier which based on the logistic regression to detect the  phishing sites that relies on our selected features of the  URLs. Because of the mismatched distributions of the  features in different phishing domains, we employ multiple  models for different regions. Since it is impossible for us to  collect enough data from a new region to rebuild the  detection model, we adjust the existing models by the  transfer learning algorithm to solve these problems. The  proposed algorithm was evaluated on a real-world task of  detecting the phishing websites. After a number of  experiments, our proposed transfer learning algorithm  achieves more than 97% accuracy. The result demonstrates  the use of this algorithm in the anti-phishing scenario is  feasible and ready for our large scale detection engine. 

  5. Convolution power spectrum analysis for FMRI data based on prior image signal.

    Science.gov (United States)

    Zhang, Jiang; Chen, Huafu; Fang, Fang; Liao, Wei

    2010-02-01

    Functional MRI (fMRI) data-processing methods based on changes in the time domain involve, among other things, correlation analysis and use of the general linear model with statistical parametric mapping (SPM). Unlike conventional fMRI data analysis methods, which aim to model the blood-oxygen-level-dependent (BOLD) response of voxels as a function of time, the theory of power spectrum (PS) analysis focuses completely on understanding the dynamic energy change of interacting systems. We propose a new convolution PS (CPS) analysis of fMRI data, based on the theory of matched filtering, to detect brain functional activation for fMRI data. First, convolution signals are computed between the measured fMRI signals and the image signal of prior experimental pattern to suppress noise in the fMRI data. Then, the PS density analysis of the convolution signal is specified as the quantitative analysis energy index of BOLD signal change. The data from simulation studies and in vivo fMRI studies, including block-design experiments, reveal that the CPS method enables a more effective detection of some aspects of brain functional activation, as compared with the canonical PS SPM and the support vector machine methods. Our results demonstrate that the CPS method is useful as a complementary analysis in revealing brain functional information regarding the complex nature of fMRI time series.

  6. A Fuzzy-Based Prior Knowledge Diagnostic Model with Multiple Attribute Evaluation

    Science.gov (United States)

    Lin, Yi-Chun; Huang, Yueh-Min

    2013-01-01

    Prior knowledge is a very important part of teaching and learning, as it affects how instructors and students interact with the learning materials. In general, tests are used to assess students' prior knowledge. Nevertheless, conventional testing approaches usually assign only an overall score to each student, and this may mean that students are…

  7. A Fuzzy-Based Prior Knowledge Diagnostic Model with Multiple Attribute Evaluation

    Science.gov (United States)

    Lin, Yi-Chun; Huang, Yueh-Min

    2013-01-01

    Prior knowledge is a very important part of teaching and learning, as it affects how instructors and students interact with the learning materials. In general, tests are used to assess students' prior knowledge. Nevertheless, conventional testing approaches usually assign only an overall score to each student, and this may mean that students are…

  8. Reliable dual tensor model estimation in single and crossing fibers based on jeffreys prior

    NARCIS (Netherlands)

    J. Yang (Jianfei); D.H.J. Poot; M.W.A. Caan (Matthan); Su, T. (Tanja); C.B. Majoie (Charles); L.J. van Vliet (Lucas); F. Vos (Frans)

    2016-01-01

    textabstractPurpose This paper presents and studies a framework for reliable modeling of diffusion MRI using a data-acquisition adaptive prior. Methods Automated relevance determination estimates the mean of the posterior distribution of a rank-2 dual tensor model exploiting Jeffreys prior (JARD).

  9. Development of a Diagnostic System Using a Testing-Based Approach for Strengthening Student Prior Knowledge

    Science.gov (United States)

    Lin, Yi-Chun; Lin, Yen-Ting; Huang, Yueh-Min

    2011-01-01

    Students learn new instructions well by building on relevant prior knowledge, as it affects how instructors and students interact with the learning materials. Moreover, studies have found that good prior knowledge can enable students to attain better learning motivation, comprehension, and performance. This suggests it is important to assist…

  10. Validity and reliability of an IMU-based method to detect APAs prior to gait initiation.

    Science.gov (United States)

    Mancini, Martina; Chiari, Lorenzo; Holmstrom, Lars; Salarian, Arash; Horak, Fay B

    2016-01-01

    Anticipatory postural adjustments (APAs) prior to gait initiation have been largely studied in traditional, laboratory settings using force plates under the feet to characterize the displacement of the center of pressure. However clinical trials and clinical practice would benefit from a portable, inexpensive method for characterizing APAs. Therefore, the main objectives of this study were (1) to develop a novel, automatic IMU-based method to detect and characterize APAs during gait initiation and (2) to measure its test-retest reliability. Experiment I was carried out in the laboratory to determine the validity of the IMU-based method in 10 subjects with PD (OFF medication) and 12 control subjects. Experiment II was carried out in the clinic, to determine test-retest reliability of the IMU-based method in a different set of 17 early-to-moderate, treated subjects with PD (tested ON medication) and 17 age-matched control subjects. Results showed that gait initiation characteristics (both APAs and 1st step) detected with our novel method were significantly correlated to the characteristics calculated with a force plate and motion analysis system. The size of APAs measured with either inertial sensors or force plate was significantly smaller in subjects with PD than in control subjects (p<0.05). Test-retest reliability for the gait initiation characteristics measured with inertial sensors was moderate-to-excellent (0.56

  11. New bis(azobenzocrown)s with dodecylmethylmalonyl linkers as ionophores for sodium selective potentiometric sensors

    OpenAIRE

    2016-01-01

    Novel biscrowns 1 and 2 were synthesized from 13-membered azobenzocrown ethers containing bromoalkylenoxy chains in para position relative to the azo group. The synthesized diester molecules are dodecylmethylmalonic acid derivatives differing by the linker length. The synthesized compounds have the potential of being used as sodium ionophores in ion-selective electrodes. They were characterized and used as ionophores in classic and miniature, solid contact (screen-printed and glassy carbon) m...

  12. SU-E-J-68: Adaptive Radiotherapy of Head and Neck Cancer: Re-Planning Based On Prior Dose

    Energy Technology Data Exchange (ETDEWEB)

    Dogan, N; Padgett, K [University of Miami Miller School of Medicine, Miami, FL (United States); Evans, J; Sleeman, W; Song, S [Virginia Commonwealth University, Richmond, VA (United States); Fatyga, M [Mayo Clinic Arizona, Phoenix, AZ (United States)

    2015-06-15

    Purpose: Adaptive Radiotherapy (ART) with frequent CT imaging has been used to improve dosimetric accuracy by accounting for anatomical variations, such as primary tumor shrinkage and/or body weight loss, in Head and Neck (H&N) patients. In most ART strategies, the difference between the planned and the delivered dose is estimated by generating new plans on repeated CT scans using dose-volume constraints used with the initial planning CT without considering already delivered dose. The aim of this study was to assess the dosimetric gains achieved by re-planning based on prior dose by comparing them to re-planning not based-on prior dose for H&N patients. Methods: Ten locally-advanced H&N cancer patients were selected for this study. For each patient, six weekly CT imaging were acquired during the course of radiotherapy. PTVs, parotids, cord, brainstem, and esophagus were contoured on both planning and six weekly CT images. ART with weekly re-plans were done by two strategies: 1) Generating a new optimized IMRT plan without including prior dose from previous fractions (NoPriorDose) and 2) Generating a new optimized IMRT plan based on the prior dose given from previous fractions (PriorDose). Deformable image registration was used to accumulate the dose distributions between planning and six weekly CT scans. The differences in accumulated doses for both strategies were evaluated using the DVH constraints for all structures. Results: On average, the differences in accumulated doses for PTV1, PTV2 and PTV3 for NoPriorDose and PriorDose strategies were <2%. The differences in Dmean to the cord and brainstem were within 3%. The esophagus Dmean was reduced by 2% using PriorDose. PriorDose strategy, however, reduced the left parotid D50 and Dmean by 15% and 14% respectively. Conclusion: This study demonstrated significant parotid sparing, potentially reducing xerostomia, by using ART with IMRT optimization based on prior dose for weekly re-planning of H&N cancer patients.

  13. Aerosol optical depth retrieval in the Arctic region using MODIS based on prior knowledge

    Directory of Open Access Journals (Sweden)

    L. Mei

    2011-12-01

    Full Text Available The Arctic is especially vulnerable to the long-term transport of aerosols and other pollutants because aerosols can affect the albedo of the surface by deposition on snow and ice. However, aerosol observations for this area are sparse and hence there is considerable uncertainty in the knowledge on the properties of the Arctic aerosol. Arctic aerosol observations are needed to fill this gap because these are among the basic and most important parameters for researching the Arctic environment. Atmospheric remote sensing using satellites offers us an opportunity to describe the aerosol distribution in terms of both local, regional and global coverage. However, AOD retrieval over a bright surface remains a difficult task because it is hard to separate and explicitly describe the contribution of the observed signal reflected by the variable surface and back scattering by the semi-transparent aerosols, especially with a large solar or sensor zenith angle. In this paper, an approach using a synergetic approach with Moderate Resolution Imaging Spectroradiometer (MODIS data based on prior knowledge is presented. The detailed analysis of the model demonstrates that it is suitable for Arctic region AOD retrieval. Six AERONET stations at high latitude (Andenes, Barrow, Ittoqqortoormiit, OPAL, Thule, and Tiksi were used for validation, and the correlation coefficient between retrieved AODs and AERONET AODs was 0.75 and the retrieval absolute error is approximately 0.1, while the relative error is 20% (at some stations with clear skies as low as 10% was found. Furthermore, the Russian wildfires that occurred in late July of 2010 and their effect on the Arctic environment is presented; Satellite retrieved AODs in the Arctic increased to 1.0 during 1 August and 15 August 2010, even 2.0, during the burning phase, and subsequently returned to normal values (lower than 0.1, which was fully in line with the AERONET observations. This indicates that the fire plumes

  14. Biomarker-based salinity reconstruction immediately prior to the Messinian Salinity Crisis (Sorbas Basin, Spain)

    Science.gov (United States)

    Mayser, Jan Peter; Martins, Cesar; Flecker, Rachel; Pancost, Rich D.

    2014-05-01

    The salinity crisis which occurred in the Mediterranean at the end of the Miocene (5.97 to 5.33 Ma) was a time of large-scale environmental change and thick evaporite deposits formed both in the deep basins and on the surrounding margins. Late Miocene successions in the Sorbas Basin, south east Spain preserve sediments that were deposited immediately prior to the Messinian Salinity Crisis (MSC) and during the initial phase of gypsum precipitation (Sierro et al., 2001). Salinity changes are indicated by evaporite formation and fluctuations in faunal assemblages, but these provide threshold measurements only e.g. gypsum forms at a salinity of 130 psu. By analysing the lipid biomarker composition by GC and HPLC-MS after Soxhlet extraction of pre-MSC sediments we aim to reconstruct granular changes in salinity leading up to initial gypsum precipitation. The pre-MSC sediments comprise regular alternations of marine marls and terrigenous clays with interspersed diatomites. This lithological cyclicity is climatically forced by orbitally-driven changes in insolation (Krijgsman et al., 1999) such that specific lithologies are thought to accumulate during precession minima (homogeneous marls) and maxima (laminated marls). By targeting these lithologies for salinity reconstruction we can evaluate the orbital control on quantified environmental change. The reconstruction of the salinity is predominantly based on the ACE proxy introduced by Turich and Freeman (2011). The GDGT-based proxy can show differences over a wide range of salinity, because Archaea can survive over a much larger salinity range than haptophyte algae or other plankton and can therefore also record the salinity signal over a wider range. This makes it suitable for the broad salinity ranges leading up to the MSC e.g. ~35 to 130 psu. Turich et al. (2011) already have published 10 low resolution salinity values for pre-MSC sediments from Torrente Vaccarizzo and Serra Pirciata on Sicily. Our high resolution

  15. Cosaliency Detection Based on Intrasaliency Prior Transfer and Deep Intersaliency Mining.

    Science.gov (United States)

    Zhang, Dingwen; Han, Junwei; Han, Jungong; Shao, Ling

    2016-06-01

    As an interesting and emerging topic, cosaliency detection aims at simultaneously extracting common salient objects in multiple related images. It differs from the conventional saliency detection paradigm in which saliency detection for each image is determined one by one independently without taking advantage of the homogeneity in the data pool of multiple related images. In this paper, we propose a novel cosaliency detection approach using deep learning models. Two new concepts, called intrasaliency prior transfer and deep intersaliency mining, are introduced and explored in the proposed work. For the intrasaliency prior transfer, we build a stacked denoising autoencoder (SDAE) to learn the saliency prior knowledge from auxiliary annotated data sets and then transfer the learned knowledge to estimate the intrasaliency for each image in cosaliency data sets. For the deep intersaliency mining, we formulate it by using the deep reconstruction residual obtained in the highest hidden layer of a self-trained SDAE. The obtained deep intersaliency can extract more intrinsic and general hidden patterns to discover the homogeneity of cosalient objects in terms of some higher level concepts. Finally, the cosaliency maps are generated by weighted integration of the proposed intrasaliency prior, deep intersaliency, and traditional shallow intersaliency. Comprehensive experiments over diverse publicly available benchmark data sets demonstrate consistent performance gains of the proposed method over the state-of-the-art cosaliency detection methods.

  16. Polymeric optical sensors for selective and sensitive nitrite detection using cobalt(III) corrole and rhodium(III) porphyrin as ionophores

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Si; Wo, Yaqi; Meyerhoff, Mark E., E-mail: mmeyerho@umich.edu

    2014-09-16

    Highlights: • We examine cobalt(III) corroles and rhodium(III) porphyrins as ionophores in polymeric films for optical sensors to detect nitrite. • Different types of proton chromoionophores are evaluated to optimize nitrite response. • Selectivity over lipophilic anions such as perchlorate and thiocyanate is observed. • Both ionophores yield optical sensors that are fully reversible. • The cobalt(III) corrole based sensor is employed to determine nitric oxide emission rates from NO donor doped polymers with good accuracy. - Abstract: Cobalt(III) 5,10,15-tris(4-tert-butylphenyl) corrole with a triphenylphosphine axial ligand and rhodium(III) 5,10,15,20-tetra(p-tert-butylphenyl) porphyrin are incorporated into plasticized poly(vinyl chloride) films to fabricate nitrite-selective bulk optodes via absorbance measurements. The resulting films yield sensitive, fast and fully reversible response toward nitrite with significantly enhanced nitrite selectivity over other anions including lipophilic anions such as thiocyanate and perchlorate. The selectivity patterns differ greatly from the Hofmeister series based on anion lipophilicity and are consistent with selectivity obtained with potentiometric sensors based on the same ionophores. The optical nitrite sensors are shown to be useful for detecting rates of emission of nitric oxide (NO) from NO releasing polymers containing S-nitroso-N-acetyl-DL-penicillamine.

  17. N′, N″, N‴-tris(2-pyridyloxymethyl) ethane as ionophore in potentiometric sensor for Pb(II) ions

    Indian Academy of Sciences (India)

    Pawan Kumar; Ashok Kumar S K; Susheel K Mittal

    2014-01-01

    N′,N″,N‴ tris(2-pyridyloxymethyl) ethane (TPOME) has been used as an ionophore in a polyvinylchloride (PVC)-based membrane. Membrane electrode with a composition 30:5:62:3 (PVC:TPOME: o-NPOE:NaTPB) exhibits Nernstian response towards Pb(II) ions with a slope of 30mV/decade, over a concentration range of 1 × 10−5 M to 1 × 10−1 M. Potential response remains almost unchanged over pH range of 3.7-6.4. The electrode shows fast response time of 15 ± 2 s and a lifetime of four months. It shows good selectivity for Pb(II) ions over other mono-, di- and trivalent cations. Electrode response is satisfactory in mixed solvent media up to 30% (v/v) non-aqueous contents. Selectivity of the ionophore for Pb(II) ions was determined by spectrophotometric method. The electrode can also be used as an indicator electrode in potentiometric titration of Pb(II) ions with standard chromate solution and its determination in real-life samples. Surface morphology of membrane electrode at different stages of its development and use is also discussed.

  18. The Influence of Self-Regulated Learning and Prior Knowledge on Knowledge Acquisition in Computer-Based Learning Environments

    Science.gov (United States)

    Bernacki, Matthew

    2010-01-01

    This study examined how learners construct textbase and situation model knowledge in hypertext computer-based learning environments (CBLEs) and documented the influence of specific self-regulated learning (SRL) tactics, prior knowledge, and characteristics of the learner on posttest knowledge scores from exposure to a hypertext. A sample of 160…

  19. Investigating the Effectiveness of Inquiry-Based Instruction on Students with Different Prior Knowledge and Reading Abilities

    Science.gov (United States)

    Wang, Jing-Ru; Wang, Yuh-Chao; Tai, Hsin-Jung; Chen, Wen-Ju

    2010-01-01

    This study examined the differential impacts of an inquiry-based instruction on conceptual changes across levels of prior knowledge and reading ability. The instrument emphasized four simultaneously important components: conceptual knowledge, reading ability, attitude toward science, and learning environment. Although the learning patterns and…

  20. Thiopental and Phenytoin as Novel Ionophores for Potentiometric Determination of Lead (II Ions

    Directory of Open Access Journals (Sweden)

    Yasser M. Abd EL-Karem

    2009-03-01

    Full Text Available Two novel polymeric membrane sensors for the analysis of Pb(II have been developed based ontwo therapeutic drugs, thiopental (TP and phenytoin (PT as two new ionophores and potassium tetrakis(p-chlorophenyl borate (KTpClPB as a lipophilic additive, in plasticized PVC membranes. The sensors show a Nernstian response for Pb(II ions over the wide concentration ranges of 1×10-2 - 7×10-6 M and 1×10-2 - 8×10-6 M for the sensors based on thiopental and phenytoin, respectively. The proposed sensors have a fast response time and can be used for more than nine weeks without any considerable divergence in potentials. The sensors exhibit comparatively good selectivity with respect to alkaline, alkaline earth and some transition and heavy metal ions. They were employed for direct determination of lead in solder alloys and in galena rocks with a good agreement with the obtained results by atomic absorption spectroscopy.

  1. Magnesium ionophore II as an extraction agent for trivalent europium and americium

    Energy Technology Data Exchange (ETDEWEB)

    Makrlik, Emanuel [Czech Univ. of Life Sciences, Prague (Czech Republic). Faculty of Environmental Sciences; Vanura, Petr [Univ. of Chemistry and Technology, Prague (Czech Republic). Dept. of Analytical Chemistry

    2016-11-01

    Solvent extraction of microamounts of trivalent europium and americium into nitrobenzene by using a mixture of hydrogen dicarbollylcobaltate (H{sup +}B{sup -}) and magnesium ionophore II (L) was studied. The equilibrium data were explained assuming that the species HL{sup +}, HL{sup +}{sub 2}, ML{sup 3+}{sub 2}, and ML{sup 3+}{sub 3} (M{sup 3+} = Eu{sup 3+}, Am{sup 3+}; L=magnesium, ionophore II) are extracted into the nitrobenzene phase. Extraction and stability constants of the cationic complex species in nitrobenzene saturated with water were determined and discussed. From the experimental results it is evident that this effective magnesium ionophore II receptor for the Eu{sup 3+} and Am{sup 3+} cations could be considered as a potential extraction agent for nuclear waste treatment.

  2. Semantically-based priors and nuanced knowledge core for Big Data, Social AI, and language understanding.

    Science.gov (United States)

    Olsher, Daniel

    2014-10-01

    Noise-resistant and nuanced, COGBASE makes 10 million pieces of commonsense data and a host of novel reasoning algorithms available via a family of semantically-driven prior probability distributions. Machine learning, Big Data, natural language understanding/processing, and social AI can draw on COGBASE to determine lexical semantics, infer goals and interests, simulate emotion and affect, calculate document gists and topic models, and link commonsense knowledge to domain models and social, spatial, cultural, and psychological data. COGBASE is especially ideal for social Big Data, which tends to involve highly implicit contexts, cognitive artifacts, difficult-to-parse texts, and deep domain knowledge dependencies.

  3. Esophagus Segmentation from 3D CT Data Using Skeleton Prior-Based Graph Cut

    Directory of Open Access Journals (Sweden)

    Damien Grosgeorge

    2013-01-01

    Full Text Available The segmentation of organs at risk in CT volumes is a prerequisite for radiotherapy treatment planning. In this paper, we focus on esophagus segmentation, a challenging application since the wall of the esophagus, made of muscle tissue, has very low contrast in CT images. We propose in this paper an original method to segment in thoracic CT scans the 3D esophagus using a skeleton-shape model to guide the segmentation. Our method is composed of two steps: a 3D segmentation by graph cut with skeleton prior, followed by a 2D propagation. Our method yields encouraging results over 6 patients.

  4. Determination of ionophore coccidiostat salinomycine in premixes and poultry feeding stuffs by liquid chromatography after post-column derivatisation

    Directory of Open Access Journals (Sweden)

    Kostadinović Ljiljana M.

    2014-01-01

    Full Text Available Coccidiosis is a common parasitic disease of broiler chickens caused by single-celled protozoan parasites of the genus Eimeria which are commonly referred to as coccidian. This is an infective disease of the digestive tract which is most frequent with poultry, causing a decrease in daily increment, prolonged fattening, poorer skin pigmentation, slower feed conversion and increased mortality. The disease is caused by Protozoas from the genera of Eimeria, Isospora and Cryptospora, and it is manifested by damaging the intestine epithelial cells, less frequently the bile duct and renal tubuli. Coccidiosis is traditionally controlled by chemotherapy. There are many anticoccidial preparations which are used in the prevention of coccidiosis. We are chose a polyether monocarboxylic acid - salinomycine. Salinomycin is monovalent carboxyl-polyether ionophores. Salinomycin, produced by Streptomyces albus, destroys the cell membranes and causes their lysis. Salinomycin and other ionophoric antibiotics combine with a number of mono and divalent cations and in the form of bi-complexes make it possible to transfer metal ions through lipid hydrophobic membrane, and when they are added to diet, they change bioavailability, gut uptake and absorption and reserves of nutrient tissues. In this paper has been developed and validated process of Liquid chromatography determination of ionophoric coccidiostat salinomycin with UV spectrophotometric detection and post-column derivatisation with dimethylaminobenzaldehyde (DMAB. The method is based on extraction of salinomycin in animal feed samples using mixture acetonitrile-water (80:20, v/v and purification of extracts obtained by the filter 0,2 μm Acrodisc® PSF. The relative standard deviation (RSD for reproducibility and accuracy varied from 2,4 to 8,8% and from 2,6% to 8,8%, respectively and the values for the relative recovery rate ranged from 89 to 98%. The limit of detection (LOD and limit of quantification (LOQ

  5. Roscovitine in combination with calcium ionophore induces oocyte activation through reduction of M-phase promoting factor activity in mice.

    Science.gov (United States)

    Iba, Tomomi; Yano, Yuya; Umeno, Mayumi; Hinokio, Kenji; Kuwahara, Akira; Irahara, Minoru; Yamano, Shuji; Yasui, Toshiyuki

    2012-11-01

    The aim of the present study was to determine oocyte activation and change in M-phase promoting factor (MPF) activity induced by treatment with calcium ionophore and roscovitine in comparison with those induced by treatment with roscovitine alone and treatment with calcium ionophore and puromycin in mice. Freshly ovulated oocytes obtained from 6-8-week-old mice were divided into five groups (no activation treatment; 5 μM calcium ionophore A23187; 50 μM roscovitine; 5 μM calcium ionophore and 10 μg/ml puromycin; and 5 μM calcium ionophore and 50 μM roscovitine) and were incubated for 6 h. Oocyte activation, assessed by morphological changes, and changes in MPF activity in the five groups at 0, 2, 4 and 6 h of incubation were examined. Activated oocytes were defined as oocytes with at least one pronucleus. Oocytes treated with roscovitine alone were not activated during the 6-h incubation period. All of the oocytes in the calcium ionophore with puromycin group and in the calcium ionophore with roscovitine group were activated. The percentage activity of MPF in oocytes treated with roscovitine alone was decreased after 2 h and increased after 4 h of incubation. The percentage activity of MPF in oocytes treated with calcium ionophore and roscovitine was significantly decreased with suppression of MPF activity being maintained for 6 h, and this change was similar to that in oocytes treated with calcium ionophore and puromycin. Roscovitine with calcium ionophore is effective for induction of oocyte activation through suppression of MPF activity in mice.

  6. Underwater image enhancement based on the dark channel prior and attenuation compensation

    Science.gov (United States)

    Guo, Qingwen; Xue, Lulu; Tang, Ruichun; Guo, Lingrui

    2017-10-01

    Aimed at the two problems of underwater imaging, fog effect and color cast, an Improved Segmentation Dark Channel Prior (ISDCP) defogging method is proposed to solve the fog effects caused by physical properties of water. Due to mass refraction of light in the process of underwater imaging, fog effects would lead to image blurring. And color cast is closely related to different degree of attenuation while light with different wavelengths is traveling in water. The proposed method here integrates the ISDCP and quantitative histogram stretching techniques into the image enhancement procedure. Firstly, the threshold value is set during the refinement process of the transmission maps to identify the original mismatching, and to conduct the differentiated defogging process further. Secondly, a method of judging the propagating distance of light is adopted to get the attenuation degree of energy during the propagation underwater. Finally, the image histogram is stretched quantitatively in Red-Green-Blue channel respectively according to the degree of attenuation in each color channel. The proposed method ISDCP can reduce the computational complexity and improve the efficiency in terms of defogging effect to meet the real-time requirements. Qualitative and quantitative comparison for several different underwater scenes reveals that the proposed method can significantly improve the visibility compared with previous methods.

  7. Cognitive Temporal Document Priors

    NARCIS (Netherlands)

    Peetz, M.H.; de Rijke, M.

    2013-01-01

    Temporal information retrieval exploits temporal features of document collections and queries. Temporal document priors are used to adjust the score of a document based on its publication time. We consider a class of temporal document priors that is inspired by retention functions considered in cogn

  8. Carboxylic Acid Ionophores as Probes of the Role of Calcium in Biological Systems

    Science.gov (United States)

    Reed, P. W.

    1983-01-01

    The biological effects of calcium ionophores are described, focusing on arachidonic acid oxygenation, and the formation of a number of oxygenated metabolites of arachidonic acid. These metabolites are involved in a number of bodily functions, and their production may be regulated by calcium.

  9. Effects of ionophores on Enterococcus faecalis and E. faecium growth in pure and mixed ruminal culture

    Science.gov (United States)

    Enterococcus faecalis and faecium are Gram-positive human pathogens that can live in the gastrointestinal tract of food animals. Vancomycin-resistant enterococci (VRE) are an increasing threat to humans as a nosocomial infection, as well as a reservoir of antibiotic resistance genes. Ionophores ar...

  10. Quantification of four ionophores in soil, sediment and manure using pressurised liquid extraction

    DEFF Research Database (Denmark)

    Bak, Søren Alex; Hansen, Martin; Pedersen, Kenneth Munk

    2013-01-01

    A multi-residue pressurised liquid extraction (PLE) methodology has been established for the determination of the four ionophores: lasalocid, monensin, salinomycin and narasin in solid environmental matrices. The PLE methodology is combined with solid phase extraction as clean-up using liquid...

  11. A Solid-Contact Ion Selective Electrode for Copper(II Using a Succinimide Derivative as Ionophore

    Directory of Open Access Journals (Sweden)

    Mihaela Dana Tutulea-Anastasiu

    2013-04-01

    Full Text Available All-solid-state sensors with polyvinyl chloride (PVC-based membranes using off-the-shelf N-hydroxysuccinimide (NHS and succinimide (Succ ionophores were prepared using DOP (dioctyl phthalate and NPOE (ortho-nitrophenyloctyl ether as plasticizers. Good responses were obtained when NHS was used. The potentiometric response of the proposed electrode is independent of pH over the range 2–6. The electrode shows a fast response time of 0.25 s. The electrode exhibits a Super-Nernstian response, with 37.5 mV/decade, with a potentiometric detection limit of 4.4 µM. The proposed sensor revealed good selectivity towards a group of transition metal ions.

  12. Improving the Pattern Reproducibility of Multiple-Point-Based Prior Models Using Frequency Matching

    DEFF Research Database (Denmark)

    Cordua, Knud Skou; Hansen, Thomas Mejer; Mosegaard, Klaus

    2014-01-01

    Some multiple-point-based sampling algorithms, such as the snesim algorithm, rely on sequential simulation. The conditional probability distributions that are used for the simulation are based on statistics of multiple-point data events obtained from a training image. During the simulation, data ...

  13. Using prior knowledge in SVD-based parameter estimation for magnetic resonance spectroscopy--the ATP example.

    Science.gov (United States)

    Stoica, Petre; Selén, Yngve; Sandgren, Niclas; Van Huffel, Sabine

    2004-09-01

    We introduce the knowledge-based singular value decomposition (KNOB-SVD) method for exploiting prior knowledge in magnetic resonance (MR) spectroscopy based on the SVD of the data matrix. More specifically, we assume that the MR data are well modeled by the superposition of a given number of exponentially damped sinusoidal components and that the dampings alphakappa, frequencies omegakappa, and complex amplitudes rhokappa of some components satisfy the following relations: alphakappa = alpha (alpha = unknown), omegakappa = omega + (kappa- 1)delta (omega = unknown, delta = known), and rhokappa = Ckapparho (rho = unknown, ckappa = known real constants). The adenosine triphosphate (ATP) complex, which has one triple peak and two double peaks whose dampings, frequencies, and amplitudes may in some cases be known to satisfy the above type of relations, is used as a vehicle for describing our SVD-based method throughout the paper. By means of numerical examples, we show that our method provides more accurate parameter estimates than a commonly used general-purpose SVD-based method and a previously suggested prior knowledge-based SVD method.

  14. Novel joint TOA/RSSI-based WCE location tracking method without prior knowledge of biological human body tissues.

    Science.gov (United States)

    Ito, Takahiro; Anzai, Daisuke; Jianqing Wang

    2014-01-01

    This paper proposes a novel joint time of arrival (TOA)/received signal strength indicator (RSSI)-based wireless capsule endoscope (WCE) location tracking method without prior knowledge of biological human tissues. Generally, TOA-based localization can achieve much higher localization accuracy than other radio frequency-based localization techniques, whereas wireless signals transmitted from a WCE pass through various kinds of human body tissues, as a result, the propagation velocity inside a human body should be different from one in free space. Because the variation of propagation velocity is mainly affected by the relative permittivity of human body tissues, instead of pre-measurement for the relative permittivity in advance, we simultaneously estimate not only the WCE location but also the relative permittivity information. For this purpose, this paper first derives the relative permittivity estimation model with measured RSSI information. Then, we pay attention to a particle filter algorithm with the TOA-based localization and the RSSI-based relative permittivity estimation. Our computer simulation results demonstrates that the proposed tracking methods with the particle filter can accomplish an excellent localization accuracy of around 2 mm without prior information of the relative permittivity of the human body tissues.

  15. Web Design Curriculum and Syllabus Based on Web Design Practice and Students' Prior Knowledge

    Science.gov (United States)

    Krunic, Tanja; Ruzic-Dimitrijevic, Ljiljana; Petrovic, Branka; Farkas, Robert

    2006-01-01

    The Advanced Technical School from Novi Sad set up a completely new study group for web design in 2004. The main goals of the paper are to explain the steps that were taken in starting this group, and to present the educational program based on our own research through the organization of the group and course descriptions. Since there is a…

  16. Factors Affecting Learning of Vector Math from Computer-Based Practice: Feedback Complexity and Prior Knowledge

    Science.gov (United States)

    Heckler, Andrew F.; Mikula, Brendon D.

    2016-01-01

    In experiments including over 450 university-level students, we studied the effectiveness and time efficiency of several levels of feedback complexity in simple, computer-based training utilizing static question sequences. The learning domain was simple vector math, an essential skill in introductory physics. In a unique full factorial design, we…

  17. Web Design Curriculum and Syllabus Based on Web Design Practice and Students' Prior Knowledge

    Science.gov (United States)

    Krunic, Tanja; Ruzic-Dimitrijevic, Ljiljana; Petrovic, Branka; Farkas, Robert

    2006-01-01

    The Advanced Technical School from Novi Sad set up a completely new study group for web design in 2004. The main goals of the paper are to explain the steps that were taken in starting this group, and to present the educational program based on our own research through the organization of the group and course descriptions. Since there is a…

  18. Patch-based image reconstruction for PET using prior-image derived dictionaries

    Science.gov (United States)

    Tahaei, Marzieh S.; Reader, Andrew J.

    2016-09-01

    In PET image reconstruction, regularization is often needed to reduce the noise in the resulting images. Patch-based image processing techniques have recently been successfully used for regularization in medical image reconstruction through a penalized likelihood framework. Re-parameterization within reconstruction is another powerful regularization technique in which the object in the scanner is re-parameterized using coefficients for spatially-extensive basis vectors. In this work, a method for extracting patch-based basis vectors from the subject’s MR image is proposed. The coefficients for these basis vectors are then estimated using the conventional MLEM algorithm. Furthermore, using the alternating direction method of multipliers, an algorithm for optimizing the Poisson log-likelihood while imposing sparsity on the parameters is also proposed. This novel method is then utilized to find sparse coefficients for the patch-based basis vectors extracted from the MR image. The results indicate the superiority of the proposed methods to patch-based regularization using the penalized likelihood framework.

  19. A Novel Prior- and Motion-Based Compressed Sensing Method for Small-Animal Respiratory Gated CT.

    Directory of Open Access Journals (Sweden)

    Juan F P J Abascal

    Full Text Available Low-dose protocols for respiratory gating in cardiothoracic small-animal imaging lead to streak artifacts in the images reconstructed with a Feldkamp-Davis-Kress (FDK method. We propose a novel prior- and motion-based reconstruction (PRIMOR method, which improves prior-based reconstruction (PBR by adding a penalty function that includes a model of motion. The prior image is generated as the average of all the respiratory gates, reconstructed with FDK. Motion between respiratory gates is estimated using a nonrigid registration method based on hierarchical B-splines. We compare PRIMOR with an equivalent PBR method without motion estimation using as reference the reconstruction of high dose data. From these data acquired with a micro-CT scanner, different scenarios were simulated by changing photon flux and number of projections. Methods were evaluated in terms of contrast-to-noise-ratio (CNR, mean square error (MSE, streak artefact indicator (SAI, solution error norm (SEN, and correction of respiratory motion. Also, to evaluate the effect of each method on lung studies quantification, we have computed the Jaccard similarity index of the mask obtained from segmenting each image as compared to those obtained from the high dose reconstruction. Both iterative methods greatly improved FDK reconstruction in all cases. PBR was prone to streak artifacts and presented blurring effects in bone and lung tissues when using both a low number of projections and low dose. Adopting PBR as a reference, PRIMOR increased CNR up to 33% and decreased MSE, SAI and SEN up to 20%, 4% and 13%, respectively. PRIMOR also presented better compensation for respiratory motion and higher Jaccard similarity index. In conclusion, the new method proposed for low-dose respiratory gating in small-animal scanners shows an improvement in image quality and allows a reduction of dose or a reduction of the number of projections between two and three times with respect to previous PBR

  20. Multimodal region-consistent saliency based on foreground and background priors for indoor scene

    Science.gov (United States)

    Zhang, J.; Wang, Q.; Zhao, Y.; Chen, S. Y.

    2016-09-01

    Visual saliency is a very important feature for object detection in a complex scene. However, image-based saliency is influenced by clutter background and similar objects in indoor scenes, and pixel-based saliency cannot provide consistent saliency to a whole object. Therefore, in this paper, we propose a novel method that computes visual saliency maps from multimodal data obtained from indoor scenes, whilst keeping region consistency. Multimodal data from a scene are first obtained by an RGB+D camera. This scene is then segmented into over-segments by a self-adapting approach to combine its colour image and depth map. Based on these over-segments, we develop two cues as domain knowledge to improve the final saliency map, including focus regions obtained from colour images, and planar background structures obtained from point cloud data. Thus, our saliency map is generated by compounding the information of the colour data, the depth data and the point cloud data in a scene. In the experiments, we extensively compare the proposed method with state-of-the-art methods, and we also apply the proposed method to a real robot system to detect objects of interest. The experimental results show that the proposed method outperforms other methods in terms of precisions and recall rates.

  1. Bayesian seismic inversion based on rock-physics prior modeling for the joint estimation of acoustic impedance, porosity and lithofacies

    Energy Technology Data Exchange (ETDEWEB)

    Passos de Figueiredo, Leandro, E-mail: leandrop.fgr@gmail.com [Physics Department, Federal University of Santa Catarina, Florianópolis (Brazil); Grana, Dario [Department of Geology and Geophysics, University of Wyoming, Laramie (United States); Santos, Marcio; Figueiredo, Wagner [Physics Department, Federal University of Santa Catarina, Florianópolis (Brazil); Roisenberg, Mauro [Informatic and Statistics Department, Federal University of Santa Catarina, Florianópolis (Brazil); Schwedersky Neto, Guenther [Petrobras Research Center, Rio de Janeiro (Brazil)

    2017-05-01

    We propose a Bayesian approach for seismic inversion to estimate acoustic impedance, porosity and lithofacies within the reservoir conditioned to post-stack seismic and well data. The link between elastic and petrophysical properties is given by a joint prior distribution for the logarithm of impedance and porosity, based on a rock-physics model. The well conditioning is performed through a background model obtained by well log interpolation. Two different approaches are presented: in the first approach, the prior is defined by a single Gaussian distribution, whereas in the second approach it is defined by a Gaussian mixture to represent the well data multimodal distribution and link the Gaussian components to different geological lithofacies. The forward model is based on a linearized convolutional model. For the single Gaussian case, we obtain an analytical expression for the posterior distribution, resulting in a fast algorithm to compute the solution of the inverse problem, i.e. the posterior distribution of acoustic impedance and porosity as well as the facies probability given the observed data. For the Gaussian mixture prior, it is not possible to obtain the distributions analytically, hence we propose a Gibbs algorithm to perform the posterior sampling and obtain several reservoir model realizations, allowing an uncertainty analysis of the estimated properties and lithofacies. Both methodologies are applied to a real seismic dataset with three wells to obtain 3D models of acoustic impedance, porosity and lithofacies. The methodologies are validated through a blind well test and compared to a standard Bayesian inversion approach. Using the probability of the reservoir lithofacies, we also compute a 3D isosurface probability model of the main oil reservoir in the studied field.

  2. Prior-knowledge treatment planning for volumetric arc therapy using feature-based database mining.

    Science.gov (United States)

    Schreibmann, Eduard; Fox, Tim

    2014-03-06

    Treatment planning for volumetric arc therapy (VMAT) is a lengthy process that requires many rounds of optimizations to obtain the best treatment settings and optimization constraints for a given patient's geometry. We propose a feature-selection search engine that explores previously treated cases of similar anatomy, returning the optimal plan configurations and attainable DVH constraints. Using an institutional database of 83 previously treated cases of prostate carcinoma treated with volumetric-modulated arc therapy, the search procedure first finds the optimal isocenter position with an optimization procedure, then ranks the anatomical similarity as the mean distance between targets. For the best matching plan, the planning information is reformatted to the DICOM format and imported into the treatment planning system to suggest isocenter, arc directions, MLC patterns, and optimization constraints that can be used as starting points in the optimization process. The approach was tested to create prospective treatment plans based on anatomical features that match previously treated cases from the institution database. By starting from a near-optimal solution and using previous optimization constraints, the best matching test only required simple optimization steps to further decrease target inhomogeneity, ultimately reducing time spend by the therapist in planning arcs' directions and lengths.

  3. Main Road Extraction from ZY-3 Grayscale Imagery Based on Directional Mathematical Morphology and VGI Prior Knowledge in Urban Areas.

    Science.gov (United States)

    Liu, Bo; Wu, Huayi; Wang, Yandong; Liu, Wenming

    2015-01-01

    Main road features extracted from remotely sensed imagery play an important role in many civilian and military applications, such as updating Geographic Information System (GIS) databases, urban structure analysis, spatial data matching and road navigation. Current methods for road feature extraction from high-resolution imagery are typically based on threshold value segmentation. It is difficult however, to completely separate road features from the background. We present a new method for extracting main roads from high-resolution grayscale imagery based on directional mathematical morphology and prior knowledge obtained from the Volunteered Geographic Information found in the OpenStreetMap. The two salient steps in this strategy are: (1) using directional mathematical morphology to enhance the contrast between roads and non-roads; (2) using OpenStreetMap roads as prior knowledge to segment the remotely sensed imagery. Experiments were conducted on two ZiYuan-3 images and one QuickBird high-resolution grayscale image to compare our proposed method to other commonly used techniques for road feature extraction. The results demonstrated the validity and better performance of the proposed method for urban main road feature extraction.

  4. Main Road Extraction from ZY-3 Grayscale Imagery Based on Directional Mathematical Morphology and VGI Prior Knowledge in Urban Areas.

    Directory of Open Access Journals (Sweden)

    Bo Liu

    Full Text Available Main road features extracted from remotely sensed imagery play an important role in many civilian and military applications, such as updating Geographic Information System (GIS databases, urban structure analysis, spatial data matching and road navigation. Current methods for road feature extraction from high-resolution imagery are typically based on threshold value segmentation. It is difficult however, to completely separate road features from the background. We present a new method for extracting main roads from high-resolution grayscale imagery based on directional mathematical morphology and prior knowledge obtained from the Volunteered Geographic Information found in the OpenStreetMap. The two salient steps in this strategy are: (1 using directional mathematical morphology to enhance the contrast between roads and non-roads; (2 using OpenStreetMap roads as prior knowledge to segment the remotely sensed imagery. Experiments were conducted on two ZiYuan-3 images and one QuickBird high-resolution grayscale image to compare our proposed method to other commonly used techniques for road feature extraction. The results demonstrated the validity and better performance of the proposed method for urban main road feature extraction.

  5. 3D printing based on cardiac CT assists anatomic visualization prior to transcatheter aortic valve replacement.

    Science.gov (United States)

    Ripley, Beth; Kelil, Tatiana; Cheezum, Michael K; Goncalves, Alexandra; Di Carli, Marcelo F; Rybicki, Frank J; Steigner, Mike; Mitsouras, Dimitrios; Blankstein, Ron

    2016-01-01

    3D printing is a promising technique that may have applications in medicine, and there is expanding interest in the use of patient-specific 3D models to guide surgical interventions. To determine the feasibility of using cardiac CT to print individual models of the aortic root complex for transcatheter aortic valve replacement (TAVR) planning as well as to determine the ability to predict paravalvular aortic regurgitation (PAR). This retrospective study included 16 patients (9 with PAR identified on blinded interpretation of post-procedure trans-thoracic echocardiography and 7 age, sex, and valve size-matched controls with no PAR). 3D printed models of the aortic root were created from pre-TAVR cardiac computed tomography data. These models were fitted with printed valves and predictions regarding post-implant PAR were made using a light transmission test. Aortic root 3D models were highly accurate, with excellent agreement between annulus measurements made on 3D models and those made on corresponding 2D data (mean difference of -0.34 mm, 95% limits of agreement: ± 1.3 mm). The 3D printed valve models were within 0.1 mm of their designed dimensions. Examination of the fit of valves within patient-specific aortic root models correctly predicted PAR in 6 of 9 patients (6 true positive, 3 false negative) and absence of PAR in 5 of 7 patients (5 true negative, 2 false positive). Pre-TAVR 3D-printing based on cardiac CT provides a unique patient-specific method to assess the physical interplay of the aortic root and implanted valves. With additional optimization, 3D models may complement traditional techniques used for predicting which patients are more likely to develop PAR. Copyright © 2016 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

  6. Performance Evaluation of Alternative Relative Orientation Procedures for UAV-based Imagery with Prior Flight Trajectory Information

    Science.gov (United States)

    He, F.; Habib, A.

    2016-06-01

    Thanks to recent advances at the hardware (e.g., emergence of reliable platforms at low cost) and software (e.g., automated identification of conjugate points in overlapping images) levels, UAV-based 3D reconstruction has been widely used in various applications. However, mitigating the impact of outliers in automatically matched points in UAV imagery, especially when dealing with scenes that has poor and/or repetitive texture, remains to be a challenging task. In spite of the fact that existing literature has already demonstrated that incorporating prior motion information can play an important role in increasing the reliability of the matching process, there is a lack of methodologies that are mainly suited for UAV imagery. Assuming the availability of prior information regarding the trajectory of a UAV-platform, this paper presents a two-point approach for reliable estimation of Relative Orientation Parameters (ROPs) of UAV-based images. This approach is based on the assumption that the UAV platform is moving at a constant flying height while maintaining the camera in a nadir-looking orientation. For this flight scenario, a closed-form solution that can be derived using a minimum of two pairs of conjugate points is established. In order to evaluate the performance of the proposed approach, experimental tests using real stereo-pairs acquired from different UAV platforms have been conducted. The derived results from the comparative performance analysis against the Nistér five-point approach demonstrate that the proposed two-point approach is capable of providing reliable estimate of the ROPs from UAV-based imagery in the presence of poor and/or repetitive texture with high percentage of matching outliers.

  7. Stereotactic Ablative Radiosurgery for Locally-Advanced or Recurrent Skull Base Malignancies with Prior External Beam Radiation Therapy

    Directory of Open Access Journals (Sweden)

    Karen Mann Xu

    2015-03-01

    Full Text Available Purpose: Stereotactic ablative radiotherapy (SABR is an attractive modality to treat malignancies invading the skull base as it can deliver a highly conformal dose with minimal toxicity. However, variation exists in the prescribed dose and fractionation. The purpose of our study is to examine the local control, survival and toxicities in SABR for the treatment of malignant skull base tumors. Methods and Materials: A total of 31 patients and 40 locally-advanced or recurrent head and neck malignancies involving the skull base treated with a common SABR regimen which delivers a radiation dose of 44 Gy in 5 fractions from January 1st, 2004 to December 31st, 2013 were retrospectively reviewed. The local control rate (LC, progression-free survival rate (PFS, overall survival rate (OS and toxicities were reported.Results: The median follow-up time of all patients was 11.4 months (range: 0.6-67.2 months. The median tumor volume was 27 cm3 (range: 2.4-205 cm3. All patients received prior EBRT with a median radiation dose of 64 Gy (range: 24-75.6 Gy delivered in 12 to 42 fractions. 20 patients had surgeries prior to SABR. 19 patients received chemotherapy. Specifically, 8 patients received concurrent cetuximab (ErbituxTM with SABR. The median time-to-progression (TTP was 3.3 months (range: 0-16.9 months. For the 29 patients (93.5% who died, the median time from the end of first SABR to death was 10.3 months (range: 0.5-41.4 months. The estimated 1-year overall survival (OS rate was 35%. The estimated 2-year OS rate was 12%. Treatment was well-tolerated without grade 4 or 5 treatment-related toxicities.Conclusions: SABR has been shown to achieve low toxicities in locally-advanced or recurrent, previously irradiated head and neck malignancies invading the skull base.

  8. Performance Evaluation of Alternative Relative Orientation Procedures for UAV-based Imagery with Prior Flight Trajectory Information

    Directory of Open Access Journals (Sweden)

    F. He

    2016-06-01

    Full Text Available Thanks to recent advances at the hardware (e.g., emergence of reliable platforms at low cost and software (e.g., automated identification of conjugate points in overlapping images levels, UAV-based 3D reconstruction has been widely used in various applications. However, mitigating the impact of outliers in automatically matched points in UAV imagery, especially when dealing with scenes that has poor and/or repetitive texture, remains to be a challenging task. In spite of the fact that existing literature has already demonstrated that incorporating prior motion information can play an important role in increasing the reliability of the matching process, there is a lack of methodologies that are mainly suited for UAV imagery. Assuming the availability of prior information regarding the trajectory of a UAV-platform, this paper presents a two-point approach for reliable estimation of Relative Orientation Parameters (ROPs of UAV-based images. This approach is based on the assumption that the UAV platform is moving at a constant flying height while maintaining the camera in a nadir-looking orientation. For this flight scenario, a closed-form solution that can be derived using a minimum of two pairs of conjugate points is established. In order to evaluate the performance of the proposed approach, experimental tests using real stereo-pairs acquired from different UAV platforms have been conducted. The derived results from the comparative performance analysis against the Nistér five-point approach demonstrate that the proposed two-point approach is capable of providing reliable estimate of the ROPs from UAV-based imagery in the presence of poor and/or repetitive texture with high percentage of matching outliers.

  9. SEMANTIC LABELLING OF ULTRA DENSE MLS POINT CLOUDS IN URBAN ROAD CORRIDORS BASED ON FUSING CRF WITH SHAPE PRIORS

    Directory of Open Access Journals (Sweden)

    W. Yao

    2017-09-01

    Full Text Available In this paper, a labelling method for the semantic analysis of ultra-high point density MLS data (up to 4000 points/m2 in urban road corridors is developed based on combining a conditional random field (CRF for the context-based classification of 3D point clouds with shape priors. The CRF uses a Random Forest (RF for generating the unary potentials of nodes and a variant of the contrastsensitive Potts model for the pair-wise potentials of node edges. The foundations of the classification are various geometric features derived by means of co-variance matrices and local accumulation map of spatial coordinates based on local neighbourhoods. Meanwhile, in order to cope with the ultra-high point density, a plane-based region growing method combined with a rule-based classifier is applied to first fix semantic labels for man-made objects. Once such kind of points that usually account for majority of entire data amount are pre-labeled; the CRF classifier can be solved by optimizing the discriminative probability for nodes within a subgraph structure excluded from pre-labeled nodes. The process can be viewed as an evidence fusion step inferring a degree of belief for point labelling from different sources. The MLS data used for this study were acquired by vehicle-borne Z+F phase-based laser scanner measurement, which permits the generation of a point cloud with an ultra-high sampling rate and accuracy. The test sites are parts of Munich City which is assumed to consist of seven object classes including impervious surfaces, tree, building roof/facade, low vegetation, vehicle and pole. The competitive classification performance can be explained by the diverse factors: e.g. the above ground height highlights the vertical dimension of houses, trees even cars, but also attributed to decision-level fusion of graph-based contextual classification approach with shape priors. The use of context-based classification methods mainly contributed to smoothing of

  10. Semantic Labelling of Ultra Dense Mls Point Clouds in Urban Road Corridors Based on Fusing Crf with Shape Priors

    Science.gov (United States)

    Yao, W.; Polewski, P.; Krzystek, P.

    2017-09-01

    In this paper, a labelling method for the semantic analysis of ultra-high point density MLS data (up to 4000 points/m2) in urban road corridors is developed based on combining a conditional random field (CRF) for the context-based classification of 3D point clouds with shape priors. The CRF uses a Random Forest (RF) for generating the unary potentials of nodes and a variant of the contrastsensitive Potts model for the pair-wise potentials of node edges. The foundations of the classification are various geometric features derived by means of co-variance matrices and local accumulation map of spatial coordinates based on local neighbourhoods. Meanwhile, in order to cope with the ultra-high point density, a plane-based region growing method combined with a rule-based classifier is applied to first fix semantic labels for man-made objects. Once such kind of points that usually account for majority of entire data amount are pre-labeled; the CRF classifier can be solved by optimizing the discriminative probability for nodes within a subgraph structure excluded from pre-labeled nodes. The process can be viewed as an evidence fusion step inferring a degree of belief for point labelling from different sources. The MLS data used for this study were acquired by vehicle-borne Z+F phase-based laser scanner measurement, which permits the generation of a point cloud with an ultra-high sampling rate and accuracy. The test sites are parts of Munich City which is assumed to consist of seven object classes including impervious surfaces, tree, building roof/facade, low vegetation, vehicle and pole. The competitive classification performance can be explained by the diverse factors: e.g. the above ground height highlights the vertical dimension of houses, trees even cars, but also attributed to decision-level fusion of graph-based contextual classification approach with shape priors. The use of context-based classification methods mainly contributed to smoothing of labelling by removing

  11. A prior-knowledge-based threshold segmentation method of forward-looking sonar images for underwater linear object detection

    Science.gov (United States)

    Liu, Lixin; Bian, Hongyu; Yagi, Shin-ichi; Yang, Xiaodong

    2016-07-01

    Raw sonar images may not be used for underwater detection or recognition directly because disturbances such as the grating-lobe and multi-path disturbance affect the gray-level distribution of sonar images and cause phantom echoes. To search for a more robust segmentation method with a reasonable computational cost, a prior-knowledge-based threshold segmentation method of underwater linear object detection is discussed. The possibility of guiding the segmentation threshold evolution of forward-looking sonar images using prior knowledge is verified by experiment. During the threshold evolution, the collinear relation of two lines that correspond to double peaks in the voting space of the edged image is used as the criterion of termination. The interaction is reflected in the sense that the Hough transform contributes to the basis of the collinear relation of lines, while the binary image generated from the current threshold provides the resource of the Hough transform. The experimental results show that the proposed method could maintain a good tradeoff between the segmentation quality and the computational time in comparison with conventional segmentation methods. The proposed method redounds to a further process for unsupervised underwater visual understanding.

  12. A NEW APPROACH FOR PROGRESSIVE DENSE RECONSTRUCTION FROM CONSECUTIVE IMAGES BASED ON PRIOR LOW-DENSITY 3D POINT CLOUDS

    Directory of Open Access Journals (Sweden)

    Z. Lari

    2017-09-01

    Full Text Available In recent years, the increasing incidence of climate-related disasters has tremendously affected our environment. In order to effectively manage and reduce dramatic impacts of such events, the development of timely disaster management plans is essential. Since these disasters are spatial phenomena, timely provision of geospatial information is crucial for effective development of response and management plans. Due to inaccessibility of the affected areas and limited budget of first-responders, timely acquisition of the required geospatial data for these applications is usually possible only using low-cost imaging and georefencing sensors mounted on unmanned platforms. Despite rapid collection of the required data using these systems, available processing techniques are not yet capable of delivering geospatial information to responders and decision makers in a timely manner. To address this issue, this paper introduces a new technique for dense 3D reconstruction of the affected scenes which can deliver and improve the needed geospatial information incrementally. This approach is implemented based on prior 3D knowledge of the scene and employs computationally-efficient 2D triangulation, feature descriptor, feature matching and point verification techniques to optimize and speed up 3D dense scene reconstruction procedure. To verify the feasibility and computational efficiency of the proposed approach, an experiment using a set of consecutive images collected onboard a UAV platform and prior low-density airborne laser scanning over the same area is conducted and step by step results are provided. A comparative analysis of the proposed approach and an available image-based dense reconstruction technique is also conducted to prove the computational efficiency and competency of this technique for delivering geospatial information with pre-specified accuracy.

  13. Prior Infarcts, Reactivity, and Angiography in Moyamoya Disease (PIRAMD): a scoring system for moyamoya severity based on multimodal hemodynamic imaging.

    Science.gov (United States)

    Ladner, Travis R; Donahue, Manus J; Arteaga, Daniel F; Faraco, Carlos C; Roach, Brent A; Davis, L Taylor; Jordan, Lori C; Froehler, Michael T; Strother, Megan K

    2017-02-01

    OBJECTIVE Quantification of the severity of vasculopathy and its impact on parenchymal hemodynamics is a necessary prerequisite for informing management decisions and evaluating intervention response in patients with moyamoya. The authors performed digital subtraction angiography and noninvasive structural and hemodynamic MRI, and they outline a new classification system for patients with moyamoya that they have named Prior Infarcts, Reactivity, and Angiography in Moyamoya Disease (PIRAMD). METHODS Healthy control volunteers (n = 11; age 46 ± 12 years [mean ± SD]) and patients (n = 25; 42 ± 13.5 years) with angiographically confirmed moyamoya provided informed consent and underwent structural (T1-weighted, T2-weighted, FLAIR, MR angiography) and hemodynamic (T2*- and cerebral blood flow-weighted) 3-T MRI. Cerebrovascular reactivity (CVR) in the internal carotid artery territory was assessed using susceptibility-weighted MRI during a hypercapnic stimulus. Only hemispheres without prior revascularization were assessed. Each hemisphere was considered symptomatic if localizing signs were present on neurological examination and/or there was a history of transient ischemic attack with symptoms referable to that hemisphere. The PIRAMD factor weighting versus symptomatology was optimized using binary logistic regression and receiver operating characteristic curve analysis with bootstrapping. The PIRAMD finding was scored from 0 to 10. For each hemisphere, 1 point was assigned for prior infarct, 3 points for reduced CVR, 3 points for a modified Suzuki Score ≥ Grade II, and 3 points for flow impairment in ≥ 2 of 7 predefined vascular territories. Hemispheres were divided into 3 severity grades based on total PIRAMD score, as follows: Grade 1, 0-5 points; Grade 2, 6-9 points; and Grade 3, 10 points. RESULTS In 28 of 46 (60.9%) hemispheres the findings met clinical symptomatic criteria. With decreased CVR, the odds ratio of having a symptomatic hemisphere was 13 (95% CI

  14. Real-time model-based image reconstruction with a prior calculated database for electrical capacitance tomography

    Science.gov (United States)

    Rodriguez Frias, Marco A.; Yang, Wuqiang

    2017-04-01

    Image reconstruction for electrical capacitance tomography is a challenging task due to the severely underdetermined nature of the inverse problem. A model-based algorithm tackles this problem by reducing the number of unknowns to be calculated from the limited number of independent measurements. The conventional model-based algorithm is implemented with a finite element method to solve the forward problem at each iteration and can produce good results. However, it is time-consuming and hence the algorithm can be used for off-line image reconstruction only. In this paper, a solution to this limitation is proposed. The model-based algorithm is implemented with a database containing a set of prior solved forward problems. In this way, the time required to perform image reconstruction is drastically reduced without sacrificing accuracy, and real-time image reconstruction achieved with up to 100 frames s‑1. Further enhancement in speed may be accomplished by implementing the reconstruction algorithm in a parallel processing general purpose graphics process unit.

  15. Knowledge-based approach for functional MRI analysis by SOM neural network using prior labels from Talairach stereotaxic space

    Science.gov (United States)

    Erberich, Stephan G.; Willmes, Klaus; Thron, Armin; Oberschelp, Walter; Huang, H. K.

    2002-04-01

    Among the methods proposed for the analysis of functional MR we have previously introduced a model-independent analysis based on the self-organizing map (SOM) neural network technique. The SOM neural network can be trained to identify the temporal patterns in voxel time-series of individual functional MRI (fMRI) experiments. The separated classes consist of activation, deactivation and baseline patterns corresponding to the task-paradigm. While the classification capability of the SOM is not only based on the distinctness of the patterns themselves but also on their frequency of occurrence in the training set, a weighting or selection of voxels of interest should be considered prior to the training of the neural network to improve pattern learning. Weighting of interesting voxels by means of autocorrelation or F-test significance levels has been used successfully, but still a large number of baseline voxels is included in the training. The purpose of this approach is to avoid the inclusion of these voxels by using three different levels of segmentation and mapping from Talairach space: (1) voxel partitions at the lobe level, (2) voxel partitions at the gyrus level and (3) voxel partitions at the cell level (Brodmann areas). The results of the SOM classification based on these mapping levels in comparison to training with all brain voxels are presented in this paper.

  16. A sub-domain based regularization method with prior information for human thorax imaging using electrical impedance tomography

    Science.gov (United States)

    In Kang, Suk; Khambampati, Anil Kumar; Jeon, Min Ho; Kim, Bong Seok; Kim, Kyung Youn

    2016-02-01

    Electrical impedance tomography (EIT) is a non-invasive imaging technique that can be used as a bed-side monitoring tool for human thorax imaging. EIT has high temporal resolution characteristics but at the same time it suffers from poor spatial resolution due to ill-posedness of the inverse problem. Often regularization methods are used as a penalty term in the cost function to stabilize the sudden changes in resistivity. In human thorax monitoring, with conventional regularization methods employing Tikhonov type regularization, the reconstructed image is smoothed between the heart and the lungs, that is, it makes it difficult to distinguish the exact boundaries of the lungs and the heart. Sometimes, obtaining structural information of the object prior to this can be incorporated into the regularization method to improve the spatial resolution along with helping create clear and distinct boundaries between the objects. However, the boundary of the heart is changed rapidly due to the cardiac cycle hence there is no information concerning the exact boundary of the heart. Therefore, to improve the spatial resolution for human thorax monitoring during the cardiac cycle, in this paper, a sub-domain based regularization method is proposed assuming the lungs and part of background region is known. In the proposed method, the regularization matrix is modified anisotropically to include sub-domains as prior information, and the regularization parameter is assigned with different weights to each sub-domain. Numerical simulations and phantom experiments for 2D human thorax monitoring are performed to evaluate the performance of the proposed regularization method. The results show a better reconstruction performance with the proposed regularization method.

  17. Comparison of an alcohol-based hand rub and water-based chlorhexidine gluconate scrub technique for hand antisepsis prior to elective surgery in horses

    OpenAIRE

    da Silveira, Eduardo Almeida; Bubeck, Kirstin A.; Batista, Edisleidy Rodriguez; Piat, Perrine; Laverty, Sheila; Beauchamp, Guy; Archambault, Marie; Elce, Yvonne

    2016-01-01

    This prospective clinical study evaluates the effectiveness of an alcohol-based hand rub (Avagard™) for pre-surgical hand antisepsis in an equine hospital and compares it with traditional scrubbing technique using 4% chlorhexidine gluconate sponges and water. Prior to elective surgery, 3 board-certified surgeons were randomly assigned to hand antisepsis with either technique. Culture samples of each hand were taken at 4 times: before and after neutral soap hand wash, after scrub or rubbing te...

  18. Graph-based surface extraction of the liver using locally adaptive priors for multimodal interventional image registration

    Science.gov (United States)

    Kadoury, Samuel; Wood, Bradford J.; Venkatesan, Aradhana M.; Ardon, Roberto; Jago, James; Kruecker, Jochen

    2012-02-01

    The 3D fusion of tracked ultrasound with a diagnostic CT image has multiple benefits in a variety of interventional applications for oncology. Still, manual registration is a considerable drawback to the clinical workflow and hinders the widespread clinical adoption of this technique. In this paper, we propose a method to allow for an image-based automated registration, aligning multimodal images of the liver. We adopt a model-based approach that rigidly matches segmented liver shapes from ultrasound (U/S) and diagnostic CT imaging. Towards this end, a novel method which combines a dynamic region-growing method with a graph-based segmentation framework is introduced to address the challenging problem of liver segmentation from U/S. The method is able to extract liver boundary from U/S images after a partial surface is generated near the principal vector from an electromagnetically tracked U/S liver sweep. The liver boundary is subsequently expanded by modeling the problem as a graph-cut minimization scheme, where cost functions used to detect optimal surface topology are determined from adaptive priors of neighboring surface points. This allows including boundaries affected by shadow areas by compensating for varying levels of contrast. The segmentation of the liver surface is performed in 3D space for increased accuracy and robustness. The method was evaluated in a study involving 8 patients undergoing biopsy or radiofrequency ablation of the liver, yielding promising surface segmentation results based on ground-truth comparison. The proposed extended segmentation technique improved the fiducial landmark registration error compared to a point-based registration (7.2mm vs. 10.2mm on average, respectively), while achieving tumor target registration errors that are statistically equivalent (p > 0.05) to state-of-the-art methods.

  19. Model-based virtual VSB mask writer verification for efficient mask error checking and optimization prior to MDP

    Science.gov (United States)

    Pack, Robert C.; Standiford, Keith; Lukanc, Todd; Ning, Guo Xiang; Verma, Piyush; Batarseh, Fadi; Chua, Gek Soon; Fujimura, Akira; Pang, Linyong

    2014-10-01

    A methodology is described wherein a calibrated model-based `Virtual' Variable Shaped Beam (VSB) mask writer process simulator is used to accurately verify complex Optical Proximity Correction (OPC) and Inverse Lithography Technology (ILT) mask designs prior to Mask Data Preparation (MDP) and mask fabrication. This type of verification addresses physical effects which occur in mask writing that may impact lithographic printing fidelity and variability. The work described here is motivated by requirements for extreme accuracy and control of variations for today's most demanding IC products. These extreme demands necessitate careful and detailed analysis of all potential sources of uncompensated error or variation and extreme control of these at each stage of the integrated OPC/ MDP/ Mask/ silicon lithography flow. The important potential sources of variation we focus on here originate on the basis of VSB mask writer physics and other errors inherent in the mask writing process. The deposited electron beam dose distribution may be examined in a manner similar to optical lithography aerial image analysis and image edge log-slope analysis. This approach enables one to catch, grade, and mitigate problems early and thus reduce the likelihood for costly long-loop iterations between OPC, MDP, and wafer fabrication flows. It moreover describes how to detect regions of a layout or mask where hotspots may occur or where the robustness to intrinsic variations may be improved by modification to the OPC, choice of mask technology, or by judicious design of VSB shots and dose assignment.

  20. The effect of the hydrogen ionophore closantel upon the pharmacology and ultrastructure of the adult liver fluke Fasciola hepatica.

    Science.gov (United States)

    Skuce, P J; Fairweather, I

    1990-01-01

    The present study describes the effects of the H+ ionophore and anthelmintic closantel upon the in vitro motility and in vivo ultrastructure of the liver fluke, Fasciola hepatica. At a concentration of 50 micrograms/ml, closantel caused an initial stimulation, then suppression of activity, which was accompanied by an increase in muscle tone and led to a spastic paralysis within 2 h. The pattern of response was similar at lower concentrations, although the initial stimulation was not always evident, but the onset of paralysis could be reached more quickly. Scanning electron microscopy revealed gross surface damage from 24 h onwards in vivo, in the form of erosion of the anterior and posterior extremities of the fluke and large-scale sloughing of the tegument on both dorsal and ventral surfaces. Tegumental changes prior to sloughing included some swelling of the basal infolds and an apical accumulation of T1 secretory bodies. In the underlying tegumental cells there was reduced secretory activity and the mitochondria were consistently swollen and deformed. Reduced secretory activity was a feature of the gastrodermal cells as well; these cells were characterized by swollen, electron-lucent mitochondria, vesiculated GER cisternae and apical blebbing of packets of cytoplasm. The vitelline follicles became severely disrupted as a result of the breakdown of the nurse cell cytoplasm. The stem and intermediate type 1 (It1) cells rounded up and showed nuclear abnormalities. There did not appear to be a severe disruption of shell protein production in the intermediate vitelline cells, but there was a noticeable absence of glycogen in the mature vitelline cells. The effects of closantel are discussed in relation to its proposed mode of action as an uncoupler of oxidative phosphorylation.

  1. Antidepressants and seizure-interactions at the GABA-receptor chloride-ionophore complex

    Energy Technology Data Exchange (ETDEWEB)

    Malatynska, E.; Knapp, R.J.; Ikeda, M.; Yamamura, H.I.

    1988-01-01

    Convulsive seizures are a potential side effect of antidepressant drug treatment and can be produced by all classes of antidepressants. It is also know that some convulsant and anticonvulsant drug actions are mediated by the GABA-receptor chloride-ionophore complex. Drugs acting at this complex appear to induce convulsions by inhibiting chloride conductance through the associated chloride channel. Using the method of GABA-stimulated /sup 36/Cl-uptake by rat cerebral cortical vesicles, we show that some antidepressant drugs can inhibit the GABA-receptor chloride uptake, and that the degree of chloride channel inhibition by these drugs correlates with the frequency of convulsive seizures induced by them.

  2. Bayesian wavelet-based image deconvolution: a GEM algorithm exploiting a class of heavy-tailed priors.

    Science.gov (United States)

    Bioucas-Dias, José M

    2006-04-01

    Image deconvolution is formulated in the wavelet domain under the Bayesian framework. The well-known sparsity of the wavelet coefficients of real-world images is modeled by heavy-tailed priors belonging to the Gaussian scale mixture (GSM) class; i.e., priors given by a linear (finite of infinite) combination of Gaussian densities. This class includes, among others, the generalized Gaussian, the Jeffreys, and the Gaussian mixture priors. Necessary and sufficient conditions are stated under which the prior induced by a thresholding/shrinking denoising rule is a GSM. This result is then used to show that the prior induced by the "nonnegative garrote" thresholding/shrinking rule, herein termed the garrote prior, is a GSM. To compute the maximum a posteriori estimate, we propose a new generalized expectation maximization (GEM) algorithm, where the missing variables are the scale factors of the GSM densities. The maximization step of the underlying expectation maximization algorithm is replaced with a linear stationary second-order iterative method. The result is a GEM algorithm of O(N log N) computational complexity. In a series of benchmark tests, the proposed approach outperforms or performs similarly to state-of-the art methods, demanding comparable (in some cases, much less) computational complexity.

  3. Exploring the Impact of Prior Knowledge and Appropriate Feedback on Students' Perceived Cognitive Load and Learning Outcomes: Animation-Based Earthquakes Instruction

    Science.gov (United States)

    Yeh, Ting-Kuang; Tseng, Kuan-Yun; Cho, Chung-Wen; Barufaldi, James P.; Lin, Mei-Shin; Chang, Chun-Yen

    2012-01-01

    The aim of this study was to develop an animation-based curriculum and to evaluate the effectiveness of animation-based instruction; the report involved the assessment of prior knowledge and the appropriate feedback approach, for the purpose of reducing perceived cognitive load and improving learning. The curriculum was comprised of five subunits…

  4. Studies on glycogen autophagy: effects of phorbol myristate acetate, ionophore A23187, or phentolamine.

    Science.gov (United States)

    Kalamidas, S A; Kotoulas, O B; Hann, A C

    2002-06-15

    The effects of agents that could manipulate the lysosomal calcium such as phorbol myristate acetate, ionophore A23187, and phentolamine on the lysosomal glycogen degradation were studied by electron microscopy, morphometric analysis, and biochemical assays in newborn rat hepatocytes. Phorbol myristate acetate, which promotes the input of calcium to lysosomes, increased the total volume of autophagic vacuoles and the activity of lysosomal glycogen-hydrolyzing acid alpha 1,4 glucosidase and decreased the fractional volume of undigested glycogen inside the autophagic vacuoles and also decreased the activity of acid mannose 6-phosphatase. Ionophore A23187, which releases lysosomal calcium, produced opposite results in these enzyme activities. Phentolamine, an alpha-adrenergic blocking agent which interferes with the generation of phosphoinositides and may activate the lysosomal calcium uptake pump, increased the total volume of autophagic vacuoles and the activity of lysosomal glycogen-hydrolyzing acid glucosidase and decreased the fractional volume of undigested glycogen inside the autophagic vacuoles. The results of this study constitute evidence that changes in lysosomal calcium may influence certain aspects of autophagy, including the degradation of glycogen inside the autophagic vacuoles. They also support our previous postulate [Kalamidas and Kotoulas (2000a,b) Histol Histopathol 15:29-35, 1011-1018] that stimulation of autophagic mechanisms in newborn rat hepatocytes may be associated with acid mannose 6-phosphatase activity-deficient lysosomes.

  5. Combined use of ionophore and virginiamycin for finishing Nellore steers fed high concentrate diets

    Directory of Open Access Journals (Sweden)

    Amoracyr José Costa Nuñez

    2013-08-01

    Full Text Available Zebu cattle fed high concentrate diets may present inconsistent performance due to the occurrence of metabolic disorders, like acidosis. The isolated use of ionophores and virginiamycin in high grain diets can improve animal performance and reduce the incidence of such disorders, but recent studies suggested that their combination may have an additive effect. Thus, 72 Nellore steers, 389 ± 15 kg initial body weight (BW, were confined and fed for 79 days to evaluate the combination of virginiamycin and salinomycin on performance and carcass traits. Animals were allocated to a randomized complete block design by BW, in a 2 × 2 factorial arrangement of treatments, with two concentrate levels (73 and 91 % and two virginiamycin levels (0 and 15 mg kg-1, and salinomycin (13 mg kg-1 included in all diets. The interaction was not significant (p > 0.05. Dry matter intake (DMI, average daily gain (ADG, gain-to-feed ratio (G:F, starch consumed, and fecal starch content were higher (p 0.05 between treatments. Starch consumed and estimated dietary net energy for maintenance (NEm and gain (NEg were higher (p < 0.05 for virginiamycin-treated animals, with no substantial effects on carcass traits. The inclusion of virginiamycin in finishing diets containing salinomycin reduced DMI while maintaining ADG and improving NEm and NEg, suggesting an additive effect of virginiamycin and ionophores, but without affecting carcass quality.

  6. Salinomycin and other polyether ionophores are a new class of antiscarring agent.

    Science.gov (United States)

    Woeller, Collynn F; O'Loughlin, Charles W; Roztocil, Elisa; Feldon, Steven E; Phipps, Richard P

    2015-02-06

    Although scarring is a component of wound healing, excessive scar formation is a debilitating condition that results in pain, loss of tissue function, and even death. Many tissues, including the lungs, heart, skin, and eyes, can develop excessive scar tissue as a result of tissue injury, chronic inflammation, or autoimmune disease. Unfortunately, there are few, if any, effective treatments to prevent excess scarring, and new treatment strategies are needed. Using HEK293FT cells stably transfected with a TGFβ-dependent luciferase reporter, we performed a small molecule screen to identify novel compounds with antiscarring activity. We discovered that the polyether ionophore salinomycin potently inhibited the formation of scar-forming myofibroblasts. Salinomycin (250 nm) blocked TGFβ-dependent expression of the cardinal myofibroblast products α smooth muscle actin, calponin, and collagen in primary human fibroblasts without causing cell death. Salinomycin blocked phosphorylation and activation of TAK1 and p38, two proteins fundamentally involved in signaling myofibroblast and scar formation. Expression of constitutively active mitogen activated kinase kinase 6, which activates p38 MAPK, attenuated the ability of salinomycin to block myofibroblast formation, demonstrating that salinomycin targets the p38 kinase pathway to disrupt TGFβ signaling. These data identify salinomycin and other polyether ionophores as novel potential antiscarring therapeutics.

  7. Comparison of an alcohol-based hand rub and water-based chlorhexidine gluconate scrub technique for hand antisepsis prior to elective surgery in horses

    Science.gov (United States)

    da Silveira, Eduardo Almeida; Bubeck, Kirstin A.; Batista, Edisleidy Rodriguez; Piat, Perrine; Laverty, Sheila; Beauchamp, Guy; Archambault, Marie; Elce, Yvonne

    2016-01-01

    This prospective clinical study evaluates the effectiveness of an alcohol-based hand rub (Avagard™) for pre-surgical hand antisepsis in an equine hospital and compares it with traditional scrubbing technique using 4% chlorhexidine gluconate sponges and water. Prior to elective surgery, 3 board-certified surgeons were randomly assigned to hand antisepsis with either technique. Culture samples of each hand were taken at 4 times: before and after neutral soap hand wash, after scrub or rubbing technique, and after surgery. There was no significant difference in mean bacterial colony forming units between scrub and rub techniques over the 3 time periods (P = 0.6), controlling for initial counts. One horse from the scrub group had a skin incision infection following stifle arthroscopy; this was resolved with medical treatment. The alcohol-based hand rub is equivalent in efficacy for pre-surgical hand antisepsis to traditional water-based scrubs in an equine hospital setting. PMID:26834268

  8. Comparison of an alcohol-based hand rub and water-based chlorhexidine gluconate scrub technique for hand antisepsis prior to elective surgery in horses.

    Science.gov (United States)

    da Silveira, Eduardo Almeida; Bubeck, Kirstin A; Batista, Edisleidy Rodriguez; Piat, Perrine; Laverty, Sheila; Beauchamp, Guy; Archambault, Marie; Elce, Yvonne

    2016-02-01

    This prospective clinical study evaluates the effectiveness of an alcohol-based hand rub (Avagard™) for pre-surgical hand antisepsis in an equine hospital and compares it with traditional scrubbing technique using 4% chlorhexidine gluconate sponges and water. Prior to elective surgery, 3 board-certified surgeons were randomly assigned to hand antisepsis with either technique. Culture samples of each hand were taken at 4 times: before and after neutral soap hand wash, after scrub or rubbing technique, and after surgery. There was no significant difference in mean bacterial colony forming units between scrub and rub techniques over the 3 time periods (P = 0.6), controlling for initial counts. One horse from the scrub group had a skin incision infection following stifle arthroscopy; this was resolved with medical treatment. The alcohol-based hand rub is equivalent in efficacy for pre-surgical hand antisepsis to traditional water-based scrubs in an equine hospital setting.

  9. Ventilation onset prior to umbilical cord clamping (physiological-based cord clamping) improves systemic and cerebral oxygenation in preterm lambs.

    Science.gov (United States)

    Polglase, Graeme R; Dawson, Jennifer A; Kluckow, Martin; Gill, Andrew W; Davis, Peter G; Te Pas, Arjan B; Crossley, Kelly J; McDougall, Annie; Wallace, Euan M; Hooper, Stuart B

    2015-01-01

    As measurement of arterial oxygen saturation (SpO2) is common in the delivery room, target SpO2 ranges allow clinicians to titrate oxygen therapy for preterm infants in order to achieve saturation levels similar to those seen in normal term infants in the first minutes of life. However, the influence of the onset of ventilation and the timing of cord clamping on systemic and cerebral oxygenation is not known. We investigated whether the initiation of ventilation, prior to, or after umbilical cord clamping, altered systemic and cerebral oxygenation in preterm lambs. Systemic and cerebral blood-flows, pressures and peripheral SpO2 and regional cerebral tissue oxygenation (SctO2) were measured continuously in apnoeic preterm lambs (126±1 day gestation). Positive pressure ventilation was initiated either 1) prior to umbilical cord clamping, or 2) after umbilical cord clamping. Lambs were monitored intensively prior to intervention, and for 10 minutes following umbilical cord clamping. Clamping the umbilical cord prior to ventilation resulted in a rapid decrease in SpO2 and SctO2, and an increase in arterial pressure, cerebral blood flow and cerebral oxygen extraction. Ventilation restored oxygenation and haemodynamics by 5-6 minutes. No such disturbances in peripheral or cerebral oxygenation and haemodynamics were observed when ventilation was initiated prior to cord clamping. The establishment of ventilation prior to umbilical cord clamping facilitated a smooth transition to systemic and cerebral oxygenation following birth. SpO2 nomograms may need to be re-evaluated to reflect physiological management of preterm infants in the delivery room.

  10. Ventilation onset prior to umbilical cord clamping (physiological-based cord clamping improves systemic and cerebral oxygenation in preterm lambs.

    Directory of Open Access Journals (Sweden)

    Graeme R Polglase

    Full Text Available As measurement of arterial oxygen saturation (SpO2 is common in the delivery room, target SpO2 ranges allow clinicians to titrate oxygen therapy for preterm infants in order to achieve saturation levels similar to those seen in normal term infants in the first minutes of life. However, the influence of the onset of ventilation and the timing of cord clamping on systemic and cerebral oxygenation is not known.We investigated whether the initiation of ventilation, prior to, or after umbilical cord clamping, altered systemic and cerebral oxygenation in preterm lambs.Systemic and cerebral blood-flows, pressures and peripheral SpO2 and regional cerebral tissue oxygenation (SctO2 were measured continuously in apnoeic preterm lambs (126±1 day gestation. Positive pressure ventilation was initiated either 1 prior to umbilical cord clamping, or 2 after umbilical cord clamping. Lambs were monitored intensively prior to intervention, and for 10 minutes following umbilical cord clamping.Clamping the umbilical cord prior to ventilation resulted in a rapid decrease in SpO2 and SctO2, and an increase in arterial pressure, cerebral blood flow and cerebral oxygen extraction. Ventilation restored oxygenation and haemodynamics by 5-6 minutes. No such disturbances in peripheral or cerebral oxygenation and haemodynamics were observed when ventilation was initiated prior to cord clamping.The establishment of ventilation prior to umbilical cord clamping facilitated a smooth transition to systemic and cerebral oxygenation following birth. SpO2 nomograms may need to be re-evaluated to reflect physiological management of preterm infants in the delivery room.

  11. Have Chinese firms learned from their prior technology in-licensing? An analysis based on patent citations

    DEFF Research Database (Denmark)

    Li-Ying, Jason; Wang, Yuandi; Salomo, Søren

    2013-01-01

    With the rapid rise of Chinese economy, now ranking as the second largest economy in the world in 2010, many Chinese firms have started taking technological lead in the global market. Nevertheless, whether Chinese firms have learned from their prior inlicensing technologies and accumulated...

  12. Fighting Prior Review.

    Science.gov (United States)

    Bowen, John

    1990-01-01

    Reviews arguments for and against prior administrative review and censorship of student expression. Suggests that prior review strips any pretense of democracy from many American educational institutions. Argues that prior review is journalistically inappropriate, educationally unsound, and practically illogical. (KEH)

  13. Cd(II and Pb(II complexes of the polyether ionophorous antibiotic salinomycin

    Directory of Open Access Journals (Sweden)

    Tanabe Makoto

    2011-09-01

    Full Text Available Abstract Background The natural polyether ionophorous antibiotics are used for the treatment of coccidiosis in poultry and ruminants. They are effective agents against infections caused by Gram-positive microorganisms. On the other hand, it was found that some of these compounds selectively bind lead(II ions in in vivo experiments, despite so far no Pb(II-containing compounds of defined composition have been isolated and characterized. To assess the potential of polyether ionophores as possible antidotes in the agriculture, a detailed study on their in vitro complexation with toxic metal ions is required. In the present paper we report for the first time the preparation and the structure elucidation of salinomycin complexes with ions of cadmium(II and lead(II. Results New metal(II complexes of the polyether ionophorous antibiotic salinomycin with Cd(II and Pb(II ions were prepared and structurally characterized by IR, FAB-MS and NMR techniques. The spectroscopic information and elemental analysis data reveal that sodium salinomycin (SalNa undergoes a reaction with heavy metal(II ions to form [Cd(Sal2(H2O2] (1 and [Pb(Sal(NO3] (2, respectively. Abstraction of sodium ions from the cavity of the antibiotic is occurring during the complexation reaction. Salinomycin coordinates with cadmium(II ions as a bidentate monoanionic ligand through the deprotonated carboxylic moiety and one of the hydroxyl groups to yield 1. Two salinomycin anions occupy the equatorial plane of the Cd(II center, while two water molecules take the axial positions of the inner coordination sphere of the metal(II cation. Complex 2 consists of monoanionic salinomycin acting in polydentate coordination mode in a molar ratio of 1: 1 to the metal ion with one nitrate ion for charge compensation. Conclusion The formation of the salinomycin heavy metal(II complexes indicates a possible antidote activity of the ligand in case of chronic/acute intoxications likely to occur in the stock

  14. Content and Timing of Feedback in a Web-based Learning Environment: Effects on Learning as a function of prior knowledge.

    NARCIS (Netherlands)

    Smits, Marieke; Boon, Jo; Sluijsmans, Dominique; Van Gog, Tamara

    2008-01-01

    Smits, M. H. S. B., Boon, J., Sluijsmans, D. M. A., & Van Gog, T. (2008). Content and timing of feedback in a web-based learning environment: Effects on learning as a function of prior knowledge. Interactive Learning Environments, 16, 183-193.

  15. ASCORBIC ACID TREATMENT TO REDUCE RESIDUAL HALOGEN-BASED OXIDANTS PRIOR TO THE DETERMINATION OF HALOGENATED DISINFECTION BYPRODUCTS IN POTABLE WATER

    Science.gov (United States)

    Treatment of potable water samples with ascorbic acid has been investigated as a means for reducing residual halogen-based oxidants (disinfectants)i.e., HOCl, Cl2, Brw and BrCl, prior to determination of EPA Method 551.1A and 551.1B analytes. These disinfection byproducts include...

  16. Can Intrapartum Cardiotocography Predict Uterine Rupture among Women with Prior Caesarean Delivery?: A Population Based Case-Control Study.

    Directory of Open Access Journals (Sweden)

    Malene M Andersen

    Full Text Available To compare cardiotocographic abnormalities recorded during labour in women with prior caesarean delivery (CD and complete uterine rupture with those recorded in controls with prior CD without uterine rupture.Women with complete uterine rupture during labour between 1997 and 2008 were identified in the Danish Medical Birth Registry (n = 181. Cases were validated by review of medical records and 53 cases with prior CD, trial of labour, available cardiotocogram (CTG and complete uterine rupture were included and compared with 43 controls with prior CD, trial of labour and available CTG. The CTG tracings were assessed by 19 independent experts divided into groups of three different experts for each tracing. The assessors were blinded to group, outcome and clinical data. They analyzed occurrence of defined abnormalities and classified the traces as normal, suspicious, pathological or pre-terminal according to international guidelines (FIGO.A pathological CTG during the first stage of labour was present in 77% of cases and in 53% of the controls (OR 2.58 [CI: 0.96-6.94] P = 0.066. Fetal tachycardia was more frequent in cases with uterine rupture (OR 2.50 [CI: 1.0-6.26] P = 0.053. Significantly more cases showed more than 10 severe variable decelerations compared with controls (OR 22 [CI: 1.54-314.2] P = 0.022. Uterine tachysystole was not correlated with the presence of uterine rupture.A pathological cardiotocogram should lead to particular attention on threatening uterine rupture but cannot be considered a strong predictor as it is common in all women with trial of labour after caesarean delivery.

  17. Development of an autonomous treatment planning strategy for radiation therapy with effective use of population-based prior data.

    Science.gov (United States)

    Wang, Huan; Dong, Peng; Liu, Hongcheng; Xing, Lei

    2017-02-01

    Current treatment planning remains a costly and labor intensive procedure and requires multiple trial-and-error adjustments of system parameters such as the weighting factors and prescriptions. The purpose of this work is to develop an autonomous treatment planning strategy with effective use of prior knowledge and in a clinically realistic treatment planning platform to facilitate radiation therapy workflow. Our technique consists of three major components: (i) a clinical treatment planning system (TPS); (ii) a formulation of decision-function constructed using an assemble of prior treatment plans; (iii) a plan evaluator or decision-function and an outer-loop optimization independent of the clinical TPS to assess the TPS-generated plan and to drive the search toward a solution optimizing the decision-function. Microsoft (MS) Visual Studio Coded UI is applied to record some common planner-TPS interactions as subroutines for querying and interacting with the TPS. These subroutines are called back in the outer-loop optimization program to navigate the plan selection process through the solution space iteratively. The utility of the approach is demonstrated by using clinical prostate and head-and-neck cases. An autonomous treatment planning technique with effective use of an assemble of prior treatment plans is developed to automatically maneuver the clinical treatment planning process in the platform of a commercial TPS. The process mimics the decision-making process of a human planner and provides a clinically sensible treatment plan automatically, thus reducing/eliminating the tedious manual trial-and-errors of treatment planning. It is found that the prostate and head-and-neck treatment plans generated using the approach compare favorably with that used for the patients' actual treatments. Clinical inverse treatment planning process can be automated effectively with the guidance of an assemble of prior treatment plans. The approach has the potential to

  18. Automated identification of brain tumours from single MR images based on segmentation with refined patient-specific priors

    Directory of Open Access Journals (Sweden)

    Ana eSanjuán

    2013-12-01

    Full Text Available Brain tumours can have different shapes or locations, making their identification very challenging. In functional MRI, it is not unusual that patients have only one anatomical image due to time and financial constraints. Here, we provide a modified automatic lesion identification (ALI procedure which enables brain tumour identification from single MR images. Our method rests on (A a modified segmentation-normalisation procedure with an explicit extra prior for the tumour and (B an outlier detection procedure for abnormal voxel (i.e. tumour classification. To minimise tissue misclassification, the segmentation-normalisation procedure requires prior information of the tumour location and extent. We therefore propose that ALI is run iteratively so that the output of Step B is used as a patient-specific prior in Step A. We test this procedure on real T1-weighted images from 18 patients, and the results were validated in comparison to two independent observers’ manual tracings. The automated procedure identified the tumours successfully with an excellent agreement with the manual segmentation (area under the ROC curve = 0.97 ± 0.03. The proposed procedure increases the flexibility and robustness of the ALI tool and will be particularly useful for lesion-behaviour mapping studies, or when lesion identification and/or spatial normalisation are problematic.

  19. Evaluation of ionophore sensitivity of Eimeria acervulina and Eimeria maxima isolated from the Algerian Jijel province poultry farms

    Science.gov (United States)

    The present study represents the first description of ionophore resistance in Eimeria recovered from commercial Algerian (Jijel-Algeria) broiler farms. Microscopy and ITS1 PCR revealed only 2 Eimeria species present in litter from these farms- namely E. acervulina and E. maxima. A pool of these is...

  20. Synthesis of Macrocyclic Ionophore for the Development of Highly Selective Chloride Sensor

    Directory of Open Access Journals (Sweden)

    Sameena Mehtab

    2015-03-01

    Full Text Available The macrocyclic ligands 3,8,12,17-tetramethyl-2,18,9,11-bipyridyl-1,4,7,10,13,16-hexaazacyclooctadecanetetrahydro bromide has been synthesized and explored as suitable ionophores for chloride selective membrane sensors. It displays Nernstian behavior (59.2 mV decade-1 across the range of 4.1 × 10-8 to 1.0 × 10-2 M. The detection limit of the electrode is ~ 15 nM and the response time and life times are 14 s and eight weeks respectively over a wide pH range (3.5 - 9.5. Interference from other anions is very low and it can be used as indicator electrode in the potentiometric titration of chloride ions and to determine chloride in agricultural soil water samples.

  1. Incorporating Prior Knowledge into KernelBased Regression%先验知识与基于核函数的回归方法的融合

    Institute of Scientific and Technical Information of China (English)

    孙喆; 张曾科; 王焕钢

    2008-01-01

    In some sample based regression tasks, the observed samples are quite few or not informative enough. As a result, the conflict between the number of samples and the model complexity emerges, and the regression mcthod will confront the dilemma whether to choose a complex model or not. Incorporating thc prior knowledge is a potential solution for this dilemma. In this paper, a sort of the prior knowledge is investigated and a novel method to incorporate it into thc kernel based regression scheme is proposed. The proposed prior knowledge bascd kcrnel regression (PKBKR) method includes two subproblems: representing the prior knowledge in the function space, and combining this representation and the training samples to obtain the regression function. A greedy algorithm for the representing step and a weighted loss function for the incorporation step are proposed. Finally, experimcnts are performed to validate the proposed PKBKR method, wherein the results show that the proposed method can achieve rclativcly high regression performance with appropriate model complexity, especially when the number of samples is small or the observation noise is large.

  2. High-Resolution, Near Real-Time Simulation of Microwave Radiance Using a Simple Land-Cover Based Emissivity Prior

    Directory of Open Access Journals (Sweden)

    Dimitrios Katsanos

    2014-01-01

    Full Text Available Satellite simulators are used to calculate the brightness temperature Tb that would be measured by a space borne sensor under a set of atmospheric conditions accounting for the radiometric characteristics of the sensor and the orbital parameters of the satellite. In this study, a simple approach is proposed for the parameterization of emissivity over land, a key parameter for the calculation of microwave Tb. The rationale is to simulate a large ensemble of emissivity values for each frequency and surface characteristics and then relate the most likely observed value with soil characteristics. The derived emissivity values are used for the simulation of Tb and simulated radiance is then compared with satellite observations. It is shown that this method improves the simulation of radiance and that it is suitable to provide a first guess of the emissivity value (a prior that can then be refined using iterative procedures.

  3. Intoxicação por antibióticos ionóforos em animais Ionophore poisoning in animals

    Directory of Open Access Journals (Sweden)

    Vivian Assunção Nogueira

    2009-03-01

    Full Text Available O uso terapêutico de antibióticos ionóforos em medicina veterinária difundiu-se muito nos últimos anos, com conseqüente aumento no risco de intoxicação em animais. Antibióticos ionóforos são usados como coccidiostáticos e como aditivo em alimentos para animais, com o propósito de estimular o desenvolvimento e o ganho de peso. Os ionóforos mais utilizados na alimentação de animais são a monensina, lasalocida, nasarina e salinomicina. Há uma grande variação na susceptibilidade dos efeitos tóxicos dos ionóforos de acordo com a espécie animal. A intoxicação pode ocorrer quando dosagens elevadas de ionóforos são adicionadas aos alimentos, ou quando ionóforos são incluídos inadvertidamente ou acidentalmente em dosagens não corretas para determinada espécie animal. Casos de intoxicação têm sido descritos em bovinos, ovinos, suínos, eqüinos, cães e aves. Para os eqüinos os ionóforos são extremamente tóxicos. São considerados seguros quando usados nas espécies-alvo, dentro das dosagens recomendadas pelo fabricante.The therapeutic use of ionophores in veterinary medicine has grown in the last years, with resultant increase in the risk of poisoning in animals. Ionophores are used as food additives as coccidiostacts in several animal species and growth promoter and bloat prevention in ruminants. The most often used ionophores are monensin, lasalocid, narasin and salinomycin. There is a great variation in the susceptibility to the toxic effect of ionophores in different animal species. Poisoning can occur when the dosage is too high or when not correct doses for a certain animal species are given. Cases of poisoning have been described in sheep, swine, horses, dogs and poultry. For horses ionophores are extremely toxic. The use of ionophores is only safe when used accordingly to the instructions of the manufacturer and especially for each animal species. In this paper the most important data regarding clinical

  4. Dwarf spheroidal J-factors without priors: A likelihood-based analysis for indirect dark matter searches

    CERN Document Server

    Chiappo, A; Conrad, J; Strigari, L E; Anderson, B; Sanchez-Conde, M A

    2016-01-01

    Line-of-sight integrals of the squared density, commonly called the J-factor, are essential for inferring dark matter annihilation signals. The J-factors of dark matter-dominated dwarf spheroidal satellite galaxies (dSphs) have typically been derived using Bayesian techniques, which for small data samples implies that a choice of priors constitutes a non-negligible systematic uncertainty. Here we report the development of a new fully frequentist approach to construct the profile likelihood of the J-factor. Using stellar kinematic data from several classical and ultra-faint dSphs, we derive the maximum likelihood value for the J-factor and its confidence intervals. We validate this method, in particular its bias and coverage, using simulated data from the Gaia Challenge. We find that the method possesses good statistical properties. The J-factors and their uncertainties are generally in good agreement with the Bayesian-derived values, with the largest deviations restricted to the systems with the smallest kine...

  5. Dwarf spheroidal J-factors without priors: A likelihood-based analysis for indirect dark matter searches

    Science.gov (United States)

    Chiappo, A.; Cohen-Tanugi, J.; Conrad, J.; Strigari, L. E.; Anderson, B.; Sánchez-Conde, M. A.

    2017-04-01

    Line-of-sight integrals of the squared density, commonly called the J-factor, are essential for inferring dark matter (DM) annihilation signals. The J-factors of DM-dominated dwarf spheroidal satellite galaxies (dSphs) have typically been derived using Bayesian techniques, which for small data samples implies that a choice of priors constitutes a non-negligible systematic uncertainty. Here we report the development of a new fully frequentist approach to construct the profile likelihood of the J-factor. Using stellar kinematic data from several classical and ultra-faint dSphs, we derive the maximum likelihood value for the J-factor and its confidence intervals. We validate this method, in particular its bias and coverage, using simulated data from the Gaia Challenge. We find that the method possesses good statistical properties. The J-factors and their uncertainties are generally in good agreement with the Bayesian-derived values, with the largest deviations restricted to the systems with the smallest kinematic data sets. We discuss improvements, extensions, and future applications of this technique.

  6. Utilization of adenosine triphosphate in rat mast cells during histamine release induced by the ionophore A23187

    DEFF Research Database (Denmark)

    Johansen, Torben

    1979-01-01

    The role of endogenous adenosine triphosphate (ATP) in histamine release from rat mast cells induced by the ionophore A23187 in vitro has been studied. 2 The amount of histamine released by calcium from rat mast cells primed with the ionophore A23187 was dependent on the ATP content of the mast...... cells. 3 In aerobic experiments a drastic reduction in mast cell ATP content was found during the time when histamine release induced by A23187 takes place. 4 Anaerobic experiments were performed with metabolic inhibitors (antimycin A, oligomycin, and carbonyl cyanide p......-trifluorometroxyphenylnydrazone), which are known to block the energy-dependent calcium uptake by isolated mitochondria. The mast cell ATP content was reduced during A23187-induced histamine release under anaerobic conditions in the presence of glucose. This indicates an increased utilization of ATP during the release process. 5...

  7. Successful pregnancy and childbirth after intracytoplasmic sperm injection with calcium ionophore oocyte activation in a globozoospermic patient.

    Science.gov (United States)

    Tejera, Alberto; Mollá, Marta; Muriel, Lourdes; Remohí, Jose; Pellicer, Antonio; De Pablo, Jose Luis

    2008-10-01

    To check the effectiveness of intracytoplasmic sperm injection (ICSI) combined with assisted oocyte activation (AOA) in a globozoospermic patient. Case report. Instituto Valenciano de Infertilidad, Valencia, Spain. A patient with globozoospermia. ICSI was administered in 14 oocytes. ICSI combined with AOA, in which a small amount of calcium was injected followed by calcium ionophore exposure, was done in 9 oocytes. Fertilization rate and embryo quality was assessed in both groups. Chemical activation increased fertilization rate (55.6% vs. 35.7%) and the number of embryos with less multinucleation on day 2 (0 vs. 60%). Two embryos generated from AOA were transferred into the uterus (on day 3), resulting in a pregnancy and a healthy newborn. The AOA with calcium ionophore treatment improved fertilization rate and quality of the embryos, and was found to be an effective method for AOA in this patient with a low fertilization rate after previous ICSI treatment.

  8. LCV model based on prior shape for melon image segmentation%甜瓜图像分割的先验LCV模型

    Institute of Scientific and Technical Information of China (English)

    朱强; 苗玉彬

    2012-01-01

    For the purpose of measuring the micro changes of morphological parameters of melon, a new LCV (Local Chan-Vese) model algorithm based on prior shape focusing on segmentation of melon image is proposed. Local boundary information image of melon is acquired through mathematical morphology algorithm, and LCV model is constructed according to the form of traditional CV model. Prior shape which is obtained by mathematical morphology and spline interpolation algorithms is constructed, and the prior shape is integrated into LCV model functional through a shape comparing function. LCV model based on prior shape is constructed. Compared with traditional edge detection and segmentation algorithms, more ideal boundary information can be obtained by this new algorithm.%以甜瓜形态的微变测量为目标,提出了基于先验形状的LCV (Local Chan-Vese)模型算法.利用形态学方法获得甜瓜的局部信息图像,仿照传统CV模型的拟合形式,建立了LCV能量模型;利用形态学方法及spine插值算法获取甜瓜的先验形状,将其通过形状比较函数嵌入到LCV模型的能量函数中,形成了新的基于先验形状的LCV模型.相比传统边缘检测和图像分割算法,该算法更易于提取出理想的边缘信息.

  9. Is orthodontics prior to 11 years of age evidence-based? A systematic review and meta-analysis.

    Science.gov (United States)

    Sunnak, R; Johal, A; Fleming, P S

    2015-05-01

    To determine whether interceptive orthodontics prior to the age of 11 years is more effective than later treatment in the short- and long-term. Multiple electronic databases were searched, authors were contacted as required and reference lists of included studies were screened. Randomised and quasi-randomised controlled trials were included, comparing children under the age of 11 years requiring interceptive orthodontic correction for a range of occlusal problems, to an untreated or positive control group. Data extraction and quality assessment were performed independently and in duplicate. Twenty-two studies were potentially eligible for meta-analysis, the majority related to growth modification. Other outcomes considered included correction of unilateral posterior crossbite, anterior openbite, extractions and ectopic maxillary canines. Meta-analysis was possible for 11 comparisons. For Class II correction in the short-term, meta-analyses demonstrated a statistically significant reduction in ANB (-1.4 degrees, 95 CI: -2.17, -0.64) and overjet (-5.81mm, 95 CI: -6.37, -5.25) with both functional appliances and headgear versus control. In the long-term, however, statistical significance was not found for the same outcomes. Treatment duration was prolonged with both functional appliances (6.85 months, 95 CI: 3.24, 10.45) and headgear (12.47 months, 95 CI: 8.67, 16.26) compared to adolescent treatments. Meta-analyses were not possible for comparisons of other interceptive treatments due to heterogeneity and methodological limitations. The results suggest a lack of evidence to prove that early treatment carries additional benefit over and above that achieved with treatment commencing later; however, this does not necessarily imply that early treatment is ineffective. Further high quality trials are required to assess the effectiveness of early treatment compared to later intervention. Interceptive orthodontics is variously recommended for a range of malocclusions both

  10. Superoxide anion production by human spermatozoa as a part of the ionophore-induced acrosome reaction process.

    Science.gov (United States)

    Griveau, J F; Renard, P; Le Lannou, D

    1995-04-01

    The involvement of superoxide anion (O2o-) in human sperm capacitation and/or acrosome reaction was investigated. Addition of superoxide dismutase (SOD) to the medium at the beginning of the capacitation process or 15 min before induction of the acrosome reaction, decreased the level of ionophore-induced acrosome reaction. Hyperactivation was unaffected by the presence of SOD during the capacitation process. Addition of calcium ionophore to the sperm suspension increased production of O2o- by the spermatozoa by four to five-fold and induced the acrosome reaction. In the presence of SOD, superoxide anion could not be detected in the medium and the rate of induced-acrosome reaction was decreased greatly. The presence of an inhibitor of protein kinase C inhibited the production of O2o- in the medium and reduced the induced-acrosome reaction. The production of O2o- and the acrosome reaction were also increased by exposure of spermatozoa to 12-myristate 13-acetate phorbol ester, a specific activator of protein kinase C. While the level of spontaneous acrosome reaction was not increased by the direct addition of O2o- to the medium, its presence induced the release of unesterified fatty acids from membrane phospholipids. These findings suggest that the production of O2o- by spermatozoa could be involved in the ionophore-induced acrosome reaction, possibly through the de-esterification of membrane phospholipids. However, this production of superoxide anion is not sufficient on its own to induce the acrosome reaction.

  11. Calcium ionophore (A-23187 induced peritoneal eicosanoid biosynthesis: a rapid method to evaluate inhibitors of arachidonic acid metabolism in vivo

    Directory of Open Access Journals (Sweden)

    T. S. Rao

    1993-01-01

    Full Text Available The present investigation characterizes calcium ionophore (A-23187 induced peritoneal eicosanoid biosynthesis in the rat. Intraperitoneal injection of A-23187 (20 μg/rat stimulated marked biosynthesis of 6-keto-PGF1α (6-KPA, TxB2, LTC4 and LTB4, with no detectable changes on levels of PGE2. Levels of all eicosanoids decreased rapidly after a peak which was seen as early as 5 min. Enzyme markers of cellular contents of neutrophils and mononuclear cells, MPO and NAG respectively, decreased rapidly after ionophore injection; this was followed by increases after 60 min. Indomethacin, a selective cyclooxygenase inhibitor, and zileuton and ICI D-2138, two selective 5-lipoxygenase inhibitors attenuated prostaglandin and leukotriene pathways respectively. Oral administration of zileuton (20 mg/kg, p.o. inhibited LTB4 biosynthesis for up to 6 h suggesting a long duration of pharmacological activity in the rats consistent with its longer half-life. The rapid onset and the magnitude of increases in levels of eicosanoids render the ionophore induced peritoneal eicosanoid biosynthesis a useful model to evaluate pharmacological profiles of inhibitors of eicosanoid pathways in vivo.

  12. Salinomycin Hydroxamic Acids: Synthesis, Structure, and Biological Activity of Polyether Ionophore Hybrids.

    Science.gov (United States)

    Borgström, Björn; Huang, Xiaoli; Chygorin, Eduard; Oredsson, Stina; Strand, Daniel

    2016-06-09

    The polyether ionophore salinomycin has recently gained attention due to its exceptional ability to selectively reduce the proportion of cancer stem cells within a number of cancer cell lines. Efficient single step strategies for the preparation of hydroxamic acid hybrids of this compound varying in N- and O-alkylation are presented. The parent hydroxamic acid, salinomycin-NHOH, forms both inclusion complexes and well-defined electroneutral complexes with potassium and sodium cations via 1,3-coordination by the hydroxamic acid moiety to the metal ion. A crystal structure of an cationic sodium complex with a noncoordinating anion corroborates this finding and, moreover, reveals a novel type of hydrogen bond network that stabilizes the head-to-tail conformation that encapsulates the cation analogously to the native structure. The hydroxamic acid derivatives display down to single digit micromolar activity against cancer cells but unlike salinomycin selective reduction of ALDH(+) cells, a phenotype associated with cancer stem cells was not observed. Mechanistic implications are discussed.

  13. Degradation and dissipation of the veterinary ionophore lasalocid in manure and soil.

    Science.gov (United States)

    Žižek, Suzana; Dobeic, Martin; Pintarič, Štefan; Zidar, Primož; Kobal, Silvestra; Vidrih, Matej

    2015-11-01

    Lasalocid is a veterinary ionophore antibiotic used for prevention and treatment of coccidiosis in poultry. It is excreted from the treated animals mostly in its active form and enters the environment with the use of contaminated manure on agricultural land. To properly assess the risk that lasalocid poses to the environment, it is necessary to know its environmental concentrations as well as the rates of its degradation in manure and dissipation in soil. These values are still largely unknown. A research was undertaken to ascertain the rate of lasalocid degradation in manure under different storage conditions (aging in a pile or composting) and on agricultural soil after using lasalocid-contaminated manure. The results have shown that there is considerable difference in lasalocid degradation between aging manure with no treatment (t1/2=61.8±1.7 d) and composting (t1/2=17.5±0.8 d). Half-lives in soil are much shorter (on average 3.1±0.4 d). On the basis of the measured concentrations of lasalocid in soil after manure application, we can conclude that it can potentially be harmful to soil organisms (PEC/PNEC ratio of 1.18), but only in a worst-case scenario of using the maximum permissible amount of manure and immediately after application. To make certain that no harmful effects occur, composting is recommended.

  14. Sofosbuvir-based therapy cures hepatitis C virus infection after prior treatment failures in a patient with concurrent lymphoma.

    Science.gov (United States)

    Romagnoli, Dante; Marrazzo, Alessandra; Ballestri, Stefano; Lonardo, Amedeo; Bertolotti, Marco

    2015-08-01

    We report on the first well-tolerated and successful use of sofosbuvir-based therapy in a patient in whom chronic infection with hepatitis C had preceded the development of B-cell non-Hodgkin's lymphoma. The patient had previously failed numerous attempts to clear the hepatitis C virus with traditional antiviral schedules. We demonstrate that sofosbuvir-based therapy resulted in cure of hepatitis C in a patient who had relapsed during combination therapy with an NS5A inhibitor, an NS3 protease inhibitor and ribavirin, as well as treatment failures to multiple courses of interferon-based therapy. This report also suggests that eradication of hepatitis C virus may result in the short-term prevention of B-cell non-Hodgkin's lymphoma relapse. The findings from our case require further validation in future cohorts of patients.

  15. Overcoming priors anxiety

    CERN Document Server

    D'Agostini, Giulio

    1999-01-01

    The choice of priors may become an insoluble problem if priors and Bayes' rule are not seen and accepted in the framework of subjectivism. Therefore, the meaning and the role of subjectivity in science is considered and defended from the pragmatic point of view of an ``experienced scientist''. The case for the use of subjective priors is then supported and some recommendations for routine and frontier measurement applications are given. The issue of reference priors is also considered from the practical point of view and in the general context of ``Bayesian dogmatism''.

  16. A simple and rapid flow cytometry-based assay to identify a competent embryo prior to embryo transfer

    OpenAIRE

    Pallinger, Eva; Bognar, Zoltan; Bodis, Jozsef; Csabai, Timea; Farkas, Nelli; Godony, Krisztina; Varnagy, Akos; Buzas, Edit; Szekeres-Bartho, Julia

    2017-01-01

    Multiple pregnancy is a risk for prematurity and preterm birth. The goal of assisted reproduction is to achieve a single pregnancy, by transferring a single embryo. This requires improved methods to identify the competent embryo. Here, we describe such a test, based on flow cytometric determination of the nucleic acid (PI+) containing extracellular vesicle (EV) count in day 5 embryo culture media. 88 women undergoing IVF were included in the study. More than 1 embryos were transferred to most...

  17. Denoising of Ictal EEG Data Using Semi-Blind Source Separation Methods Based on Time-Frequency Priors.

    Science.gov (United States)

    Hajipour Sardouie, Sepideh; Bagher Shamsollahi, Mohammad; Albera, Laurent; Merlet, Isabelle

    2015-05-01

    Removing muscle activity from ictal ElectroEncephaloGram (EEG) data is an essential preprocessing step in diagnosis and study of epileptic disorders. Indeed, at the very beginning of seizures, ictal EEG has a low amplitude and its morphology in the time domain is quite similar to muscular activity. Contrary to the time domain, ictal signals have specific characteristics in the time-frequency domain. In this paper, we use the time-frequency signature of ictal discharges as a priori information on the sources of interest. To extract the time-frequency signature of ictal sources, we use the Canonical Correlation Analysis (CCA) method. Then, we propose two time-frequency based semi-blind source separation approaches, namely the Time-Frequency-Generalized EigenValue Decomposition (TF-GEVD) and the Time-Frequency-Denoising Source Separation (TF-DSS), for the denoising of ictal signals based on these time-frequency signatures. The performance of the proposed methods is compared with that of CCA and Independent Component Analysis (ICA) approaches for the denoising of simulated ictal EEGs and of real ictal data. The results show the superiority of the proposed methods in comparison with CCA and ICA.

  18. Evaluating Facility-Based Decision-Making in Women with a Prior Cesarean Delivery and Association with Maternal and Perinatal Outcomes.

    Science.gov (United States)

    Boatin, Adeline Adwoa; Adu-Bonsaffoh, Kwame; Wylie, Blair Johnson; Obed, Samuel A

    2017-07-11

    Objective To describe facility-based decision-making for women with one prior cesarean delivery (CD) in a resource-limited setting and to characterize maternal and perinatal outcomes in these groups. Methods One year retrospective study of women with one prior CD delivering at Korle-Bu Teaching Hospital (KBTH), Ghana. Women were categorized into three groups based on initial plan of management on admission [trial of labor after cesarean (TOLAC), emergency repeat CD (EMCD) or non-emergent repeat CD (RCD)]. Characteristics and outcomes across these groups were then compared. Results During the study period, 1247 women with one prior CD delivered at KBTH, of which 377 (30.2%) were triaged to RCD, 439 (35.2%) to EMCD and 431 (34.6%) to TOLAC. Twelve uterine ruptures and no maternal deaths occurred. Perinatal mortality was 4.2% (n = 52). Compared to the RCD group, the TOLAC group had a lower risk for maternal adverse events (aOR 0.3, 95% CI 0.1-1.0; p = 0.04) and non-significant higher risk of perinatal adverse events (aOR 1.6, 95% CI 0.7-3.3; p = 0.25). Compared to women triaged to RCD, the EMCD group had a non-significant increase in risk of maternal adverse events (aOR 1.6, 95% CI 0.8-3.5; p = 0.2) and a significantly higher rate of perinatal adverse events (aOR 2.4, 95% CI 1.2-4.9; p = 0.01). Conclusions for Practice Women triaged to EMCD at admission are different when compared to women allowed a TOLAC or offered a non-emergent RCD. These women bear increased rates of adverse outcomes and should be considered as a separate group for analysis in future studies conducted in similar settings.

  19. A simple and rapid flow cytometry-based assay to identify a competent embryo prior to embryo transfer

    Science.gov (United States)

    Pallinger, Eva; Bognar, Zoltan; Bodis, Jozsef; Csabai, Timea; Farkas, Nelli; Godony, Krisztina; Varnagy, Akos; Buzas, Edit; Szekeres-Bartho, Julia

    2017-01-01

    Multiple pregnancy is a risk for prematurity and preterm birth. The goal of assisted reproduction is to achieve a single pregnancy, by transferring a single embryo. This requires improved methods to identify the competent embryo. Here, we describe such a test, based on flow cytometric determination of the nucleic acid (PI+) containing extracellular vesicle (EV) count in day 5 embryo culture media. 88 women undergoing IVF were included in the study. More than 1 embryos were transferred to most patients. In 58 women, the transfer resulted in clinical pregnancy, whereas in 30 women in implantation failure. In 112 culture media of embryos from the “clinical pregnancy” group, the number of PI+ EVs was significantly lower than in those of 49 embryos, from the “implantation failure” group. In 14 women, transfer of a single embryo resulted in a singleton pregnancy, or, transfer of two embryos in twin pregnancy. The culture media of 19 out of the 20 “confirmed competent” embryos contained a lower level of PI+ EVs than the cut off level, suggesting that the competent embryo can indeed be identified by low PI+ EV counts. We developed a noninvasive, simple, inexpensive, quick test, which identifies the embryos that are most likely to implant. PMID:28057937

  20. Do children trust based on group membership or prior accuracy? The role of novel group membership in children's trust decisions.

    Science.gov (United States)

    Elashi, Fadwa B; Mills, Candice M

    2014-12-01

    Two experiments examined how an informant's group membership can influence children's trust decisions. Participants (3- to 7-year-olds, N=162) were assigned to either the red or blue group based on their selection of a red or blue apron and watched an in-group and out-group informant provide conflicting names for a set of novel objects. When asked which informant they would prefer to rely on for new information, nearly all age groups trusted the in-group informant. Children then watched as each informant varied in accuracy by labeling either all or none of four familiar items accurately and were then asked which informant's labels they preferred for learning new information. When the in-group informant had previously demonstrated accuracy, children continued to trust the in-group informant for new information. In contrast, when the in-group informant had previously demonstrated inaccuracy, children were unsure who to trust, with only 6- and 7-year-olds showing a decrease in their trust for the inaccurate in-group informant. These findings demonstrate that group membership can skew how children encode new information and can make children uncertain about whom to trust for information.

  1. The effect of composting on the persistence of four ionophores in dairy manure and poultry litter.

    Science.gov (United States)

    Arikan, Osman A; Mulbry, Walter; Rice, Clifford

    2016-08-01

    Manure composting is a well-described approach for stabilization of nutrients and reduction of pathogens and odors. Although composting studies have shown that thermophilic temperatures and aerobic conditions can increase removal rates of selected antibiotics, comparable information is lacking for many other compounds in untreated or composted manure. The objective of this study was to determine the relative effectiveness of composting conditions to reduce concentrations of four widely used ionophore feed supplements in dairy manure and poultry litter. Replicate aliquots of fresh poultry litter and dairy manure were amended with monensin, lasalocid, salinomycin, or amprolium to 10mgkg(-1)DW. Non-amended and amended dairy manure and poultry litter aliquots were incubated at 22, 45, 55, or 65°C under moist, aerobic conditions. Residue concentrations were determined from aliquots removed after 1, 2, 4, 6, 8, and 12weeks. Results suggest that the effectiveness of composting for contaminant reduction is compound and matrix specific. Composting temperatures were not any more effective than ambient temperature in increasing the rate or extent of monensin removal in either poultry litter or dairy manure. Composting was effective for lasalocid removal in poultry litter, but is likely to be too slow to be useful in practice (8-12weeks at 65°C for >90% residue removal). Composting was effective for amprolium removal from poultry litter and salinomycin in dairy manure but both required 4-6weeks for >90% removal. However, composting did not increase the removal rates or salinomycin in poultry litter or the removal rates of lasalocid or amprolium in dairy manure.

  2. Is it possible to enhance the confidence of student dietitians prior to professional placements? A design-based research model.

    Science.gov (United States)

    Ross, L J; Mitchell, L J; Williams, L T

    2017-10-01

    Student confidence is an important contributor to a successful professional placement experience. The present study aimed to evaluate a placement preparation program for student dietitians and to assess the impact on self-rated confidence with respect to commencing placements. The present study is part of a design-based research approach that involves students in a cyclic enquiry to evaluate and improve curricula. Nutrition and Dietetics students at an Australian university participated in a 1-week mandatory workshop - Pre-Placement week (PrePW), N = 98 students: in 2015 (n = 54) and 2016 (n = 44). An online survey was conducted before and after PrePW using a five-point Likert scale (1 = not confident; 5 = very confident) to assess self-rated confidence to commence placements. Mean (SD) scores were calculated. Paired and independent t-tests evaluated within- and between-group differences, respectively. Before PrePW, the mean (SD) for student confidence to commence placements overall (in all areas of practise) was 'somewhat confident' [2.9 (0.6) in 2015 and 3.0 (0.7) in 2016]. Students were least confident to commence Clinical Practice [2015: 2.5 (0.6); 2016: 2.8 (0.6)] compared to Food Service Management (FSM) [2015: 3.2 (0.9); 2016: 3.1 (0.9)] and Community and Public Health Nutrition (CPHN) [2015: 3.3 (0.9); 2016: 3.2 (0.8)]. Student feedback from PrePW 2015 was used to change the curriculum and PrePW program. The 2016 students reported significantly greater confidence within all areas of practice: Clinical Practice [3.4 (0.6)], FSM [3.7 (0.6)] and CPHN [3.8 (0.6)], including confidence to commence placements overall [3.6 (0.6)] (P confidence in preparation for professional placement. © 2017 Commonwealth of Australia. Journal of Human Nutrition and Dietetics © 2017 The British Dietetic Association Ltd.

  3. Accreditation of Prior Experiential Learning in higher education: A European-North American comparison based on the French-Mexican cases

    Directory of Open Access Journals (Sweden)

    Pierre-Yves Sanséau

    2010-06-01

    Full Text Available In this paper, the authors examine the specificity of a new process for obtaining qualifications in a French higher education, based on the recognition of professional experience (APEL or VAE in French and the potential of its replication to other countries Firstly, the purpose focuses on the pertinence of the notion of "competence" in accreditation of prior (experiential learning (AP(EL. Although APEL approaches in the French higher education system tend to lean toward the notion of "knowledge", it appears that an approach structured by competences and based on specific frames of reference, offers great potential. Secondly, the question of the replication of APEL process in the North American context is raised with a study of the Mexican case. If educational systems of both countries don't differ much, it appears that the transfer of the APEL process could be hazardous considering the cultural and social contexts and the difficulties associated to foreign educational transfers.

  4. Setting the process parameters for the coating process in order to assure tablet appearance based on multivariate analysis of prior data.

    Science.gov (United States)

    Tanabe, Shuichi; Nakagawa, Hiroshi; Watanabe, Tomoyuki; Minami, Hidemi; Kano, Manabu; Urbanetz, Nora A

    2016-09-10

    Designing efficient, robust process parameters in drug product manufacturing is important to assure a drug's critical quality attributes. In this research, an efficient, novel procedure for a coating process parameter setting was developed, which establishes a prediction model for setting suitable input process parameters by utilizing prior manufacturing knowledge for partial least squares regression (PLSR). In the proposed procedure, target values or ranges of the output parameters are first determined, including tablet moisture content, spray mist condition, and mechanical stress on tablets. Following the preparation of predictive models relating input process parameters to corresponding output parameters, optimal input process parameters are determined using these models so that the output parameters hold within the target ranges. In predicting the exhaust air temperature output parameter, which reflects the tablets' moisture content, PLSR was employed based on prior measured data (such as batch records of other products rather than design of experiments), leading to minimal new experiments. The PLSR model was revealed to be more accurate at predicting the exhaust air temperature than a conventional semi-empirical thermodynamic model. A commercial scale verification demonstrated that the proposed process parameter setting procedure enabled assurance of the quality of tablet appearance without any trial-and-error experiments.

  5. Constructing priors in synesthesia.

    Science.gov (United States)

    van Leeuwen, Tessa M

    2014-01-01

    A new theoretical framework (PPSMC) applicable to synesthesia has been proposed, in which the discrepancy between the perceptual reality of (some) synesthetic concurrents and their subjective non-veridicality is being explained. The PPSMC framework stresses the relevance of the phenomenology of synesthesia for synesthesia research-and beyond. When describing the emergence and persistence of synesthetic concurrents under PPSMC, it is proposed that precise, high-confidence priors are crucial in synesthesia. I discuss the construction of priors in synesthesia.

  6. Extracting iron and manganese from bacteria with ionophores - a mechanism against competitors characterized by increased potency in environments low in micronutrients.

    Science.gov (United States)

    Raatschen, Nadja; Wenzel, Michaela; Ole Leichert, Lars Ingo; Düchting, Petra; Krämer, Ute; Bandow, Julia Elisabeth

    2013-04-01

    To maintain their metal ion homeostasis, bacteria critically depend on membrane integrity and controlled ion translocation. Terrestrial Streptomyces species undermine the function of the cytoplasmic membrane as diffusion barrier for metal cations in competitors using ionophores. Although the properties of the divalent cation ionophores calcimycin and ionomycin have been characterized to some extent in vitro, their effects on bacterial ion homeostasis, the factors leading to bacterial cell death, and their ecological role are poorly understood. To gain insight into their antibacterial mechanism, we determined the metal ion composition of the soil bacterium Bacillus subtilis after treatment with calcimycin and ionomycin. Within 15 min the cells lost approximately half of their cellular iron and manganese content whereas calcium levels increased. The proteomic response of B. subtilis provided evidence that disturbance of metal cation homeostasis is accompanied by intracellular oxidative stress, which was confirmed with a ROS-specific fluorescent probe. B. subtilis showed enhanced sensitivity to the ionophores in medium lacking iron or manganese. Furthermore, in the presence of ionophores bacteria were sensitive to high calcium levels. These findings suggest that divalent cation ionophores are particularly effective against competing microorganisms in soils rich in available calcium and low in available iron and manganese.

  7. Enhancement of trypsin-like enzymes by A23187 ionophore is crucial for sperm penetration through the egg vestment of the giant freshwater prawn.

    Science.gov (United States)

    Watthammawut, Atthaboon; Somrit, Monsicha; Asuvapongpatana, Somluk; Weerachatyanukul, Wattana

    2015-12-01

    We report the presence of trypsin-like enzymes preferring Boc-QAR-MCA substrate in sperm collected from different portions of male reproductive tracts of the giant freshwater prawn, Macrobrachium rosenbergii and compare enzyme activities before and after an A23187 calcium ionophore treatment. Fluorogenic enzyme assays revealed that testicular sperm lysates showed high trypsin-like enzyme activity but the activity was relatively low in vas deferens sperm lysates as well as in the live sperm. Upon sperm treatment with A23187, trypsin-like activity was greatly enhanced in distal vas deferens sperm. Substrate- and inhibitor-based localization studies indicated that the sperm trypsin-like enzymes were not of a soluble type but were rather of a membrane-borne type, localized at the anterior spike and upper part of the main body. Notable structural changes were also evident in A23187-induced sperm including extensive ruffling of the sperm membrane structure at the base of the main body thereby supporting the acrosome reaction response in this species. We further proved by substrate inhibition assays that the enhanced trypsin-like enzyme activity participates in sperm penetration through the vitelline envelope, a novel sperm-egg penetration mechanism that is unique in this species.

  8. Histamine release induced from rat mast cells by the ionophore A23187 in the absence of extracellular calcium

    DEFF Research Database (Denmark)

    Johansen, Torben

    1980-01-01

    Isolated rat mast cells were used to study whether ionophore A23187 could induce histamine release by mobilizing cellular calcium. The histamine release was a slow process which was completed after about 20 min incubation with A23187. The A23187-induced histamine release was inhibited after...... incubation of the cells with EDTA for 1 h in a 37 degrees C water bath in calcium-free medium. Reintroduction of calcium in excess of EDTA induced the release of histamine. The observations suggest that A23187 can induce histamine release by mobilizing a cellular pool of calcium....

  9. Study of Cobalt(III) Corrole as the Neutral Ionophore for Nitrite and Nitrate Detection via Polymeric Membrane Electrodes.

    Science.gov (United States)

    Yang, Si; Meyerhoff, Mark E

    2013-12-01

    Cobalt(III) 5, 10, 15-tris(4-tert-butylphenyl) corrole was synthesized and incorporated into plasticized poly(vinyl chloride) membranes and studied as a neutral carrier ionophore via potentiometry. This cobalt(III) complex has binding affinity to nitrite, and the resulting membrane electrode yields reversible and Nernstian response toward nitrite. Enhanced nitrite selectivity is observed over other anions, including lipophilic anions such as thiocyanate and perchlorate when an appropriate amount of lipophilic cationic sites are added to the membrane phase. Detection limit to nitrite is ca. 5 µM. Using tributylphosphate as the plasticizer with the cobalt(III) corrole species yields electrodes with enhanced nitrate selectivity.

  10. Monensin, a small molecule ionophore, can be used to increase high mannose levels on monoclonal antibodies generated by Chinese hamster ovary production cell-lines.

    Science.gov (United States)

    Pande, Sandhya; Rahardjo, Ayu; Livingston, Brittney; Mujacic, Mirna

    2015-07-01

    Asparagine-linked glycosylation of the constant region of monoclonal antibodies (mAbs) plays an important role in their stability and efficacy and is a critical product quality attribute that needs to be consistent between various process changes and production lots. Exact product quality match is also of the utmost importance for the development of biosimilar protein therapeutics. This poses a process development challenge since mAb glycosylation profiles can fluctuate easily with changes in process parameters. Therefore, there is a need to identify methods to modulate glycosylation levels on therapeutic antibodies during a production run in order to maintain consistent product quality profiles between different drug lots. Here, we demonstrate the use of a small molecule ionophore, monensin, to increase high mannose levels on multiple therapeutic human immunoglobulins (IgGs) in both plate-based small scale production models as well as in production bioreactors. This method is simple to implement and readily applicable for multiple production cell lines. Moreover, high mannose levels can be increased without significant negative impact on titer or cell culture performance. As such, monensin gives us a manipulable product quality lever. © 2015 Wiley Periodicals, Inc.

  11. Colander: a probability-based support vector machine algorithm for automatic screening for CID spectra of phosphopeptides prior to database search.

    Science.gov (United States)

    Lu, Bingwen; Ruse, Cristian I; Yates, John R

    2008-08-01

    We developed a probability-based machine-learning program, Colander, to identify tandem mass spectra that are highly likely to represent phosphopeptides prior to database search. We identified statistically significant diagnostic features of phosphopeptide tandem mass spectra based on ion trap CID MS/MS experiments. Statistics for the features are calculated from 376 validated phosphopeptide spectra and 376 nonphosphopeptide spectra. A probability-based support vector machine (SVM) program, Colander, was then trained on five selected features. Data sets were assembled both from LC/LC-MS/MS analyses of large-scale phosphopeptide enrichments from proteolyzed cells, tissues and synthetic phosphopeptides. These data sets were used to evaluate the capability of Colander to select pS/pT-containing phosphopeptide tandem mass spectra. When applied to unknown tandem mass spectra, Colander can routinely remove 80% of tandem mass spectra while retaining 95% of phosphopeptide tandem mass spectra. The program significantly reduced computational time spent on database search by 60-90%. Furthermore, prefiltering tandem mass spectra representing phosphopeptides can increase the number of phosphopeptide identifications under a predefined false positive rate.

  12. Mdm31 protein mediates sensitivity to potassium ionophores but does not regulate mitochondrial morphology or phospholipid trafficking in Schizosaccharomyces pombe.

    Science.gov (United States)

    Ivan, Branislav; Lajdova, Dana; Abelovska, Lenka; Balazova, Maria; Nosek, Jozef; Tomaska, Lubomir

    2015-03-01

    Mdm31p is an inner mitochondrial membrane (IMM) protein with unknown function in Saccharomyces cerevisiae. Mutants lacking Mdm31p contain only a few giant spherical mitochondria with disorganized internal structure, altered phospholipid composition and disturbed ion homeostasis, accompanied by increased resistance to the electroneutral K+ /H+ ionophore nigericin. These phenotypes are interpreted as resulting from diverse roles of Mdm31p, presumably in linking mitochondrial DNA (mtDNA) to the machinery involved in segregation of mitochondria, in mediating cation transport across IMM and in phospholipid shuttling between mitochondrial membranes. To investigate which of the roles of Mdm31p are conserved in ascomycetous yeasts, we analysed the Mdm31p orthologue in Schizosaccharomyces pombe. Our results demonstrate that, similarly to its S. cerevisiae counterpart, SpMdm31 is a mitochondrial protein and its absence results in increased resistance to nigericin. However, in contrast to S. cerevisiae, Sz. pombe cells lacking SpMdm31 are also less sensitive to the electrogenic K+ ionophore valinomycin. Moreover, mitochondria of the fission yeast mdm31Δ mutant display no changes in morphology or phospholipid composition. Therefore, in terms of function, the two orthologous proteins appear to have considerably diverged between these two evolutionarily distant yeast species, possibly sharing only their participation in ion homeostasis.

  13. Polyether ionophores: broad-spectrum and promising biologically active molecules for the control of drug-resistant bacteria and parasites

    Science.gov (United States)

    Kevin, Dion A; Meujo, Damaris AF; Hamann, Mark T

    2016-01-01

    Background As multidrug-resistant (MDR) pathogens continue to emerge, there is a substantial amount of pressure to identify new drug candidates. Carboxyl polyethers, also referred to as polyether antibiotics, are a unique class of compounds with outstanding potency against a variety of critical infectious disease targets including protozoa, bacteria and viruses. The characteristics of these molecules that are of key interest are their selectivity and high potency against several MDR etiological agents. Objective Although many studies have been published about carboxyl polyether antibiotics, there are no recent reviews of this class of drugs. The purpose of this review is to provide the reader with an overview of the spectrum of activity of polyether antibiotics, their mechanism of action, toxicity and potential as drug candidates to combat drug-resistant infectious diseases. Conclusion Polyether ionophores show a high degree of promise for the potential control of drug-resistant bacterial and parasitic infections. Despite the long history of use of this class of drugs, very limited medicinal chemistry and drug optimization studies have been reported, thus leaving the door open to these opportunities in the future. Scifinder and PubMed were the main search engines used to locate articles relevant to the topic presented in the present review. Keywords used in our search were specific names of each of the 88 compounds presented in the review as well as more general terms such as polyethers, ionophores, carboxylic polyethers and polyether antibiotics. PMID:23480512

  14. The Determination of Six Ionophore Coccidiostats in Feed by Liquid Chromatography with Postcolumn Derivatisation and Spectrofotometric/Fluorescence Detection

    Directory of Open Access Journals (Sweden)

    Małgorzata Olejnik

    2013-01-01

    Full Text Available The control of levels of anticoccidial feed additives in targeted feeds plays an important role in the assurance of efficiency of animal treatment, prevention of drug resistance, and food safety. The robust and labour-efficient method for the simultaneous determination of six ionophore coccidiostats (lasalocid, maduramicin, monensin, narasin, salinomycin, and semduramicin in targeted feed has been developed. Properly grinded and homogenized feed sample was spiked with internal standard (monesin methyl ester and extracted with methanol. The extract was analysed with reversed phase HPLC without any further purification. The separation of the analytes with conventional C18 and core-shell columns was compared. Lasalocid was analysed with fluorescence detection, whereas other ionophores were detected with UV-Vis detector after derivatisation with vanillin in the presence of sulfuric acid. Fortified samples and targeted feeds at authorized levels were used for method validation. Recovery was in the range of 85–110%, depending on the analyte. The within-laboratory reproducibility did not exceed the target value from Horwitz equation. The results of the proficiency tests (z-scores in the range of −1.0 to 1.9 confirmed the reliability of the developed protocol.

  15. Prior Knowledge Assessment Guide

    Science.gov (United States)

    2014-12-01

    determine the students’ extent of prior knowledge, not their reading speed or comprehension. Therefore, be sure to consider the reading and English ...backgrounds and skills to make training more effective, meaningful and efficient. Initial research in this tailored training program was on...history of developing measures of mental ability or cognitive skills for personnel selection; beginning with World War I (Zeidner & Drucker, 1988

  16. Arthur Prior and 'Now'

    DEFF Research Database (Denmark)

    Blackburn, Patrick Rowan; Jørgensen, Klaus Frovin

    2015-01-01

    ’s search led him through the work of Castaneda, and back to his own work on hybrid logic: the first made temporal reference philosophically respectable, the second made it technically feasible in a modal framework. With the aid of hybrid logic, Prior built a bridge from a two-dimensional UT calculus...

  17. [Effect of damage integrity rat brain synaptic membranes on the functional activity GABA(A)-receptor/Cl(-)-ionophore complex in the CNC].

    Science.gov (United States)

    Rebrov, I G; Kalinina, M V

    2013-01-01

    Functional activity of the CGABA(A)-receptor/Cl(-) ionophore complex was investigated the muscimol-stimulated entry of the radioactive isotope 36Cl(-) in synaptoneurosomes in changing the structure and permeability of neuronal membranes. Integrity of the membranes was damaged by removal of Ca(+2) and Mg(+2) from the incubation medium and by the method of freezing-thawing synaptoneurosomes. In both cases, an increase in basal 36Cl(-) entry into synaptoneurosomes, indicating increased nonspecific permeability of neuronal membranes, and decreased activity the CABA(A)-receptor/Cl(-) ionophore complex. The conclusion about the relationship of processes damage neuronal membranes and reducing the inhibitory processes in the epileptic focus.

  18. Tracking winter extra-tropical cyclones based on their relative vorticity evolution and sensitivity to prior data filtering (cycloTRACK v1.0

    Directory of Open Access Journals (Sweden)

    E. Flaounas

    2014-02-01

    Full Text Available In this study we present a new cyclone identification and tracking algorithm. Identification is based on a recognition pattern of enclosed contours of 850 hPa filtered relative vorticity values, while tracking is based on the minimization of a cost function. In particular, for each tracked cyclone our algorithm builds all possible tracks and finally chooses the one which presents the least differences of relative vorticity between consecutive track points. In parallel, for each track point the algorithm provides a cyclone area within which different physical diagnostics are calculated (such as pressure and wind speed. The area size is a function of the cyclone relative vorticity. To validate our approach we apply the algorithm on the Northern Hemisphere for the winters of 1989–2009. Three integrations of the algorithm were performed, each by using different filtering strengths. Using the three integrations, we assess the algorithm sensitivity to prior filtering the relative vorticity field. We show that filtering the input relative vorticity fields has an impact only on the weak cyclones, while in their majority the strong cyclones are independently detected and tracked.

  19. Should liquid-based cytology be performed prior to colposcopy? A comparison of the accuracy, unsatisfactory rates and cost in a tertiary referral setting.

    Science.gov (United States)

    Angstetra, Donald; Tait, Thomas; Tan, Jeffrey; Symonds, Ian

    2009-12-01

    To compare the use of liquid-based cytology (LBC) with conventional cytology (CC) in the assessment cervical intraepithelial neoplasia (CIN) prior to colposcopy. Retrospective Cohort Study. Liquid-based cytology and CC findings were compared with colposcopic assessment and directed cervical biopsy in terms of sensitivity and specificity for high grade lesions only and for any abnormalities. The degree of correlation was sought. Secondary outcomes were unsatisfactory rate and cost. A total of 1961 women had colposcopy of whom 528 had cervical biopsy. LBC and CC have similar sensitivity and specificity for both high-grade lesions and any abnormalities. In comparison with cervical biopsy, LBC and CC sensitivity for high-grade disease was 89.1% and 88.6% respectively and for any abnormalities, the sensitivity was 86.6% and 87.0%. Specificity for high-grade disease was 83.1% and 84.7% and for any abnormalities, the specificity was 53.8% and 56.4%. The unsatisfactory rate was significantly lower in LBC 4.38% compared to 1.84% (P < 0.001). However, the use of LBC was associated with an additional cost of A$1496 for each unsatisfactory smear avoided. In high prevalence setting, LBC showed no statistically significant difference in sensitivity and specificity from CC for the detection of CIN. A reduction in unsatisfactory smears was evident, but at significant additional cost.

  20. Epidemiology of paediatric injury in low income environment: Value of hospital based data prior to the institution of a formal registration system

    Directory of Open Access Journals (Sweden)

    Alain Chichom-Mefire

    2013-01-01

    Full Text Available Background: Little attention is generally paid to paediatric injuries, especially in low income settings. The aim of this study is to provide an overview of the epidemiology of hospital-based paediatric injuries in a semi-urban area in Cameroon prior to the initiation of a formal registration system. Patients and Methods: A sixteen items data collection sheet derived from a newly instituted trauma registry is used to retrospectively gather hospital-based basic information about epidemiology of injuries in patients aged 15 years or below in a low income setting. Results: Two hundred and seventy seven cases representing 16% of all injury cases could be analysed. The frequency of injuries significantly increased with age with a peak between 11 and 15 years (P < 0.001. Children in school playgrounds carried a significantly higher risk of sustaining an injury (P < 0.001. Falls and interpersonal violence were the most frequent mechanisms. The face and locomotor systems were the most commonly involved. More than 60% of patients were discharged back home. Conclusions: The data from the present registration system seem to indicate a higher injury rate in pre-adolescent children and in the school playground. The institution of a formal registration system is likely to improve the quality of data recording system.

  1. Evaluation of a novel web-based prior approval application for palivizumab prophylaxis of respiratory syncytial virus in a state Medicaid program.

    Science.gov (United States)

    Lundeen, Kristin; Pfeiffenberger, Trista; Jacobson Vann, Julie; O'Brien, Timothy; Sampson, Charlene; Wegner, Steven

    2013-03-01

    Recent disproportionate increases in use of specialty medications, such as palivizumab (Synagis), compared with steady utilization of traditional medication use, have prompted complex utilization management strategies that require frequent evaluation to facilitate cost-effectiveness while preserving patient access. Clinical criteria utilized by North Carolina (NC) Medicaid for use of palivizumab for respiratory syncytial virus (RSV) prophylaxis are consistent with the most recent guidelines published in the Red Book: Report of the Committee on Infectious Diseases. Prior to the 2011-2012 RSV season, prior approval (PA) requests were submitted by facsimile using the NC Medicaid Synagis PA form. A web-based PA application, which includes automatic approval capability, monthly dose prompts to providers, and a standardized dose projection formula, was developed for the 2011-2012 RSV season. To evaluate the timeliness of palivizumab coverage determination, compliance with palivizumab prophylaxis regimen, and the accuracy of the dose projection formula achieved with this novel web-based PA application for palivizumab prophylaxis in NC Medicaid recipients. A historically controlled retrospective cohort study was conducted in which all palivizumab PA submissions and supporting documentation from the 2010-2011 and 2011-2012 RSV seasons were retrospectively reviewed for date and time of original submission and final coverage determination. Submissions from the 2011-2012 season were also retrospectively reviewed for number of doses approved, number of doses administered, date of administration of each dose, and actual dosage administered. These data were used to evaluate compliance and the projected versus actual beneficiary weight and dose to assess the accuracy of the dose projection formula. Submissions lacking required information were excluded. Time from PA submission to coverage determination was compared between seasons using a 2-sample t-test. The proportion of

  2. Penalised Complexity Priors for Stationary Autoregressive Processes

    KAUST Repository

    Sørbye, Sigrunn Holbek

    2017-05-25

    The autoregressive (AR) process of order p(AR(p)) is a central model in time series analysis. A Bayesian approach requires the user to define a prior distribution for the coefficients of the AR(p) model. Although it is easy to write down some prior, it is not at all obvious how to understand and interpret the prior distribution, to ensure that it behaves according to the users\\' prior knowledge. In this article, we approach this problem using the recently developed ideas of penalised complexity (PC) priors. These prior have important properties like robustness and invariance to reparameterisations, as well as a clear interpretation. A PC prior is computed based on specific principles, where model component complexity is penalised in terms of deviation from simple base model formulations. In the AR(1) case, we discuss two natural base model choices, corresponding to either independence in time or no change in time. The latter case is illustrated in a survival model with possible time-dependent frailty. For higher-order processes, we propose a sequential approach, where the base model for AR(p) is the corresponding AR(p-1) model expressed using the partial autocorrelations. The properties of the new prior distribution are compared with the reference prior in a simulation study.

  3. Bayesian variable selection with spherically symmetric priors

    OpenAIRE

    De Kock, M. B.; Eggers, H. C.

    2014-01-01

    We propose that Bayesian variable selection for linear parametrisations with Gaussian iid likelihoods be based on the spherical symmetry of the diagonalised parameter space. Our r-prior results in closed forms for the evidence for four examples, including the hyper-g prior and the Zellner-Siow prior, which are shown to be special cases. Scenarios of a single variable dispersion parameter and of fixed dispersion are studied, and asymptotic forms comparable to the traditional information criter...

  4. Rapid analytical method for the determination of pesticide residues in sunflower seeds based on focused microwave-assisted Soxhlet extraction prior to gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Prados-Rosales, R C; Luque García, J L; Luque de Castro, M D

    2003-04-18

    A rapid analytical method for determination of organochlorine pesticide residues in sunflower seeds based on focused microwave-assisted Soxhlet extraction has been developed. The main factors affecting the extraction efficiency--namely microwave power, irradiation time, volume of extractant and number of cycles--were optimized by a two-level factorial fractional design. After extraction, a liquid-liquid extraction and a clean-up step including the use of Florisil macrocolumns were required prior to injection of the extracts into the chromatograph in order to isolate the pesticide residues from the lipid fraction of the original extract. The MS-MS ion preparation mode was selected due to the high sensitivity and selectivity it provides. Seed samples were used collected near a crop subjected to aerial pesticide application. Residues of hexachlorocyclohexane isomers and endosulfan were found in the seeds although they were not subjected to pesticide application, thus showing the spray-drift contamination. The validation of the proposed approach was carried out by comparison with the ISO 659-1988 reference extraction method obtaining similar, or even better efficiencies by the proposed approach.

  5. Key frames extraction of motion video based on prior knowledge%基于先验的动作视频关键帧提取

    Institute of Scientific and Technical Information of China (English)

    庞亚俊

    2016-01-01

    针对运动视频关键帧提取结果运动表达能力差的问题,以健美操运动视频关键帧提取为例,将先验语义引入到视频片段分割和关键帧提取特征提取等过程中,提出基于先验的运动视频关键帧提取算法.该算法采用韵律特征和动作节拍连续性等先验知识,将健美操动作视频分解成不同长度的动作视频片段,并利用Hog人体分类器从每一帧图像中识别出人体边界框;通过人体模板将人体边界框分割为16个运动块,并采用光流法计算每个运动块的基本运动方向;通过比较运动块基本运动方向的差异实现了动作视频关键帧提取.实验证明,该方法在保证关键帧视频压缩的情况下,具有更好地动作概括力.%To enhance the motion express ability of key frame,the key frame extraction of calisthenics video as an example,the prior is applied to the video split and key frame feature extraction and an algorithm of key frames extraction of motion video binding prior knowledge is proposed.Based on music beat detection algorithms and rhythm constraints,the calisthenics video is broken down into continuous motion video clips.Then the bounding box of human is identified from the calisthenics video picture with HoG human classifier.And then,each bounding box of human is divided into 16 motion block by body template and the optical flow is adopted to set the basic direction of motion of each block.Finally,key frames of calisthenics video are gotten by comparing the differences of the basic direction of motion of each block.Experiments show that the proposed algorithm has better motion generalization ability while keeping motion video compression efficiency.

  6. Quantum steganography using prior entanglement

    Energy Technology Data Exchange (ETDEWEB)

    Mihara, Takashi, E-mail: mihara@toyo.jp

    2015-06-05

    Steganography is the hiding of secret information within innocent-looking information (e.g., text, audio, image, video, etc.). A quantum version of steganography is a method based on quantum physics. In this paper, we propose quantum steganography by combining quantum error-correcting codes with prior entanglement. In many steganographic techniques, embedding secret messages in error-correcting codes may cause damage to them if the embedded part is corrupted. However, our proposed steganography can separately create secret messages and the content of cover messages. The intrinsic form of the cover message does not have to be modified for embedding secret messages. - Highlights: • Our steganography combines quantum error-correcting codes with prior entanglement. • Our steganography can separately create secret messages and the content of cover messages. • Errors in cover messages do not have affect the recovery of secret messages. • We embed a secret message in the Steane code as an example of our steganography.

  7. Effect of heparin, caffeine and calcium ionophore A23187 on in vitro induction of the acrosome reaction of fresh ram spermatozoa

    Directory of Open Access Journals (Sweden)

    K.H. El-Shahat

    2016-04-01

    Conclusion: The best concentration of heparin, caffeine and ionophore A23187 are 75 μg/mL, 1 mg/mL, 1.55 mM/mL for 3, 1, 4 h incubation respectively and can be used for in vitro fertilization in sheep.

  8. A new ion imprinted polymer based on Ru(III)-thiobarbituric acid complex for solid phase extraction of ruthenium(III) prior to its determination by ETAAS.

    Science.gov (United States)

    Zambrzycka, Elżbieta; Godlewska-Żyłkiewicz, Beata

    2014-01-01

    A new ruthenium ion imprinted polymer was prepared from the Ru(III) 2-thiobarbituric acid complex (the template), methacrylic acid or acrylamide (the functional monomers), and ethylene glycol dimethacrylate (the cross-linking agent) using 2,2'-azobisisobutyronitrile as the radical initiator. The ion imprinted polymer was characterized and used as a selective sorbent for the solid phase extraction of Ru(III) ions. The effects of type of functional monomer, sample volume, solution pH and flow rate on the extraction efficiency were studied in the dynamic mode. Ru(III) ion was quantitatively retained on the sorbents in the pH range from 3.5 to 10, and can be eluted with 4 mol L(-1) aqueous ammonia. The affinity of Ru(III) for the ion imprinted polymer based on the acrylamide monomer is weaker than that for the polymer based on the methacrylic acid monomer, which therefore was used in interference studies and in analytical applications. Following extraction of Ru(III) ions with the imprint and their subsequent elution from the polymer with aqueous ammonia, Ru(III) was detected by electrothermal atomic absorption spectrometry with a detection limit of 0.21 ng mL(-1). The method was successfully applied to the determination of trace amounts of Ru(III) in water, waste, road dust and platinum ore (CRM SARM 76) with a reproducibility (expressed as RSD) below 6.4 %. FigureThe new ion imprinted polymer was prepared and used for the separation of ruthenium from water and most complex environmental samples, such as road dust and platinum ore (CRM SARM 76) prior ETAAS determination.

  9. Production of arachidonic acid metabolites by macrophages exposed in vitro to asbestos, carbonyl iron particles, or calcium ionophore.

    Science.gov (United States)

    Kouzan, S; Brody, A R; Nettesheim, P; Eling, T

    1985-04-01

    Consequent to asbestos deposition, alveolar macrophages (AM) accumulate at alveolar duct bifurcations where they phagocytize fibers. Because phagocytosis can stimulate the release of arachidonic acid (AA) metabolites, the possibility that secretion of these powerful mediators of inflammation might be induced by chrysotile asbestos was investigated in vitro. Rat AM were treated in vitro with chrysotile asbestos, and the cyclooxygenase products--prostaglandins, thromboxane B2 (TXB2), 12-hydroxy-5,8,10-heptadecatrienoic acid (HHT)--and lipoxygenase products--leukotrienes (LT), hydroxyeicosatetraenoic acids (HETE)--secreted in the medium were isolated by high-performance liquid chromatography. Composition of the AA metabolites released was compared with that from those stimulated by the calcium ionophore A 23187 (20 microM) and by another particulate phagocytic stimulus, i.e., carbonyl iron beads. Calcium ionophore stimulation induced a marked release of various AA metabolites in the medium from both the cyclooxygenase pathway (HHT, TXB2, and PGE2, in decreasing quantities, respectively) and the lipoxygenase pathway (LTB4, 5-HETE, 12-HETE, and LTC4). The major product was LTB4. Treatment of the macrophages with asbestos fibers induced the release of a similar array of AA metabolites, although there were smaller amounts of LTC4 and 12-HETE, but increased quantities of PGF2 alpha. A time course study showed a steady increase in metabolite production for 1 h, followed by a plateau. In addition, the amount of metabolites released was dependent on asbestos concentrations. Phagocytosis of iron beads induced the secretion of the same metabolites as asbestos stimulation, but in larger quantities, probably reflecting the lack of cytotoxicity of the particle.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. The effect of prior assumptions over the weights in BayesPI with application to study protein-DNA interactions from ChIP-based high-throughput data

    Directory of Open Access Journals (Sweden)

    Wang Junbai

    2010-08-01

    Full Text Available Abstract Background To further understand the implementation of hyperparameters re-estimation technique in Bayesian hierarchical model, we added two more prior assumptions over the weight in BayesPI, namely Laplace prior and Cauchy prior, by using the evidence approximation method. In addition, we divided hyperparameter (regularization constants α of the model into multiple distinct classes based on either the structure of the neural networks or the property of the weights. Results The newly implemented BayesPI was tested on both synthetic and real ChIP-based high-throughput datasets to identify the corresponding protein binding energy matrices. The results obtained were encouraging: 1 there was a minor effect on the quality of predictions when prior assumptions over the weights were altered (e.g. the prior probability distributions to the weights and the number of classes to the hyperparameters in BayesPI; 2 however, there was a significant impact on the computational speed when tuning the weight prior in the model: for example, BayesPI with a Laplace weight prior achieved the best performance with regard to both the computational speed and the prediction accuracy. Conclusions From this study, we learned that it is absolutely necessary to try different prior assumptions over the weights in Bayesian hierarchical model to design an efficient learning algorithm, though the quality of the final results may not be associated with such changes. In future, the evidence approximation method can be an alternative to Monte Carlo methods for computational implementation of Bayesian hierarchical model.

  11. 基于共轭先验分布的贝叶斯网络分类模型%Bayesian network classifier based on conjugate prior distribution

    Institute of Scientific and Technical Information of China (English)

    杨颖涛; 王跃钢; 邓卫强; 徐洪涛

    2012-01-01

    针对贝叶斯网络后验概率需计算样本边际分布,计算代价大的问题,将共轭先验分布思想引入贝叶斯分类,提出了基于共轭先验分布的贝叶斯网络分类模型.针对非区间离散样本,提出一种自适应的样本离散方法,将小波包提取模拟电路故障特征离散化作为分类模型属性.仿真验证表明,模型分类效果较好,算法运行速度得以提高,也可应用于连续样本和多分类的情况,扩展了贝叶斯网络分类的应用范围.%In order to reducing calculate costs of Bayesian network,when calculating posterior probability of samples that need the marginal distribution,an approach of Bayesian network classifier based on conjugate prior distribution is proposed. An adaptive discretization method is also proposed to discrete non-interval samples. The fault feature of analog circuit extracted by wavelet packet is taken as a discrete property of Bayesian network classification model. The simulation result shows that,this classifier has high accuracy and efficiency of analog circuit fault diagnosis,and can be applied to continuous and multi-classification case,which extends the scope of application of Bayesian network classification.

  12. Automatic 3D motion estimation of left ventricle from C-arm rotational angiocardiography using a prior motion model and learning based boundary detector.

    Science.gov (United States)

    Chen, Mingqing; Zheng, Yefeng; Wang, Yang; Mueller, Kerstin; Lauritsch, Guenter

    2013-01-01

    Compared to pre-operative imaging modalities, it is more convenient to estimate the current cardiac physiological status from C-arm angiocardiography since C-arm is a widely used intra-operative imaging modality to guide many cardiac interventions. The 3D shape and motion of the left ventricle (LV) estimated from rotational angiocardiography provide important cardiac function measurements, e.g., ejection fraction and myocardium motion dyssynchrony. However, automatic estimation of the 3D LV motion is difficult since all anatomical structures overlap on the 2D X-ray projections and the nearby confounding strong image boundaries (e.g., pericardium) often cause ambiguities to LV endocardium boundary detection. In this paper, a new framework is proposed to overcome the aforementioned difficulties: (1) A new learning-based boundary detector is developed by training a boosting boundary classifier combined with the principal component analysis of a local image patch; (2) The prior LV motion model is learned from a set of dynamic cardiac computed tomography (CT) sequences to provide a good initial estimate of the 3D LV shape of different cardiac phases; (3) The 3D motion trajectory is learned for each mesh point; (4) All these components are integrated into a multi-surface graph optimization method to extract the globally coherent motion. The method is tested on seven patient scans, showing significant improvement on the ambiguous boundary cases with a detection accuracy of 2.87 +/- 1.00 mm on LV endocardium boundary delineation in the 2D projections.

  13. Reducing complexity of inverse problems using geostatistical priors

    DEFF Research Database (Denmark)

    Hansen, Thomas Mejer; Mosegaard, Klaus; Cordua, Knud Skou

    a posterior sample, can be reduced significantly using informed priors based on geostatistical models. We discuss two approaches to include such geostatistically based prior information. One is based on a parametric description of the prior likelihood that applies to 2-point based statistical models...

  14. Mirror averaging with sparsity priors

    CERN Document Server

    Dalalyan, Arnak

    2010-01-01

    We consider the problem of aggregating the elements of a (possibly infinite) dictionary for building a decision procedure, that aims at minimizing a given criterion. Along with the dictionary, an independent identically distributed training sample is available, on which the performance of a given procedure can be tested. In a fairly general set-up, we establish an oracle inequality for the Mirror Averaging aggregate based on any prior distribution. This oracle inequality is applied in the context of sparse coding for different problems of statistics and machine learning such as regression, density estimation and binary classification.

  15. Ionic liquid-based zinc oxide nanofluid for vortex assisted liquid liquid microextraction of inorganic mercury in environmental waters prior to cold vapor atomic fluorescence spectroscopic detection.

    Science.gov (United States)

    Amde, Meseret; Liu, Jing-Fu; Tan, Zhi-Qiang; Bekana, Deribachew

    2016-01-01

    Zinc oxide nanofluid (ZnO-NF) based vortex assisted liquid liquid microextraction (ZnO-NF VA-LLME) was developed and employed in extraction of inorganic mercury (Hg(2+)) in environmental water samples, followed by cold vapor atomic fluorescence spectrometry (CV-AFS). Unlike other dispersive liquid liquid microextraction techniques, ZnO-NF VA-LLME is free of volatile organic solvents and dispersive solvent consumption. Analytical signals were obtained without back-extraction from the ZnO-NF phase prior to CV-AFS determination. Some essential parameters of the ZnO-NF VA-LLME and cold vapor generation such as composition and volume of the nanofluid, vortexing time, pH of the sample solution, amount of the chelating agent, ionic strength and matrix interferences have been studied. Under optimal conditions, efficient extraction of 1ng/mL of Hg(2+) in 10mL of sample solution was achieved using 50μL of ZnO-NF. The enrichment factor before dilution, detection limits and limits of quantification of the method were about 190, 0.019 and 0.064ng/mL, respectively. The intra and inter days relative standard deviations (n=8) were found to be 4.6% and 7.8%, respectively, at 1ng/mL spiking level. The accuracy of the current method was also evaluated by the analysis of certified reference materials, and the measured Hg(2+) concentration of GBW08603 (9.6ng/mL) and GBW(E)080392 (8.9ng/mL) agreed well with their certified value (10ng/mL). The method was applied to the analysis of Hg(2+) in effluent, influent, lake and river water samples, with recoveries in the range of 79.8-92.8% and 83.6-106.1% at 1ng/mL and 5ng/mL spiking levels, respectively. Overall, ZnO-NF VA-LLME is fast, simple, cost-effective and environmentally friendly and it can be employed for efficient enrichment of the analyte from various water samples.

  16. The Role of Web-Based Health Information in Help-Seeking Behavior Prior to a Diagnosis of Lung Cancer: A Mixed-Methods Study.

    Science.gov (United States)

    Mueller, Julia; Jay, Caroline; Harper, Simon; Todd, Chris

    2017-06-08

    Delays to diagnosis in lung cancer can lead to reduced chance of survival, and patients often wait for several months before presenting symptoms. The time between first symptom recognition until diagnosis has been theorized into three intervals: symptom appraisal, help-seeking, and diagnostic interval (here: "pathway to diagnosis"). Interventions are needed to reduce delays to diagnosis in lung cancer. The Web has become an important lay health information source and could potentially play a role in this pathway to diagnosis. Our overall aim was to gain a preliminary insight into whether Web-based information plays a role in the pathway to diagnosis in lung cancer in order to assess whether it may be possible to leverage this information source to reduce delays to diagnosis. Patients diagnosed with lung cancer in the 6 months before study entry completed a survey about whether (and how, if yes) they had used the Web to appraise their condition prior to diagnosis. Based on survey responses, we purposively sampled patients and their next-of-kin for semistructured interviews (24 interviews; 33 participants). Interview data were analyzed qualitatively using Framework Analysis in the context of the pathway to diagnosis model. A total of 113 patients completed the survey (age: mean 67.0, SD 8.8 years). In all, 20.4% (23/113) reported they or next-of-kin had researched their condition online before the diagnosis. The majority of searches (20/23, 87.0%) were conducted by or with the help of next-of-kin. Interview results suggest that patients and next-of-kin perceived an impact of the information found online on all three intervals in the time to diagnosis. In the appraisal interval, participants used online information to evaluate symptoms and possible causes. In the help-seeking interval, the Web was used to inform the decision of whether to present to health services. In the diagnostic interval, it was used to evaluate health care professionals' advice, to support

  17. Terminology for pregnancy loss prior to viability

    DEFF Research Database (Denmark)

    Kolte, A M; Bernardi, L A; Christiansen, O B

    2015-01-01

    Pregnancy loss prior to viability is common and research in the field is extensive. Unfortunately, terminology in the literature is inconsistent. The lack of consensus regarding nomenclature and classification of pregnancy loss prior to viability makes it difficult to compare study results from...... different centres. In our opinion, terminology and definitions should be based on clinical findings, and when possible, transvaginal ultrasound. With this Early Pregnancy Consensus Statement, it is our goal to provide clear and consistent terminology for pregnancy loss prior to viability....

  18. The Prior-project

    DEFF Research Database (Denmark)

    Engerer, Volkmar Paul; Roued-Cunliffe, Henriette; Albretsen, Jørgen

    In this paper, we present a DH research infrastructure which relies heavily on a combination of domain knowledge with information technology. The general goal is to develop tools to aid scholars in their interpretations and understanding of temporal logic. This in turn is based on an extensive di...

  19. Toxicity of the ionophore antibiotic lasalocid to soil-dwelling invertebrates: avoidance tests in comparison to classic sublethal tests.

    Science.gov (United States)

    Žižek, Suzana; Zidar, Primož

    2013-07-01

    Lasalocid is a veterinary ionophore antibiotic used for prevention and treatment of coccidiosis in poultry. It enters the environment with the use of contaminated manure on agricultural land. Despite its extensive use, the effects of lasalocid on non-target soil organisms are poorly explored. We used classical subleathal ecotoxicity tests to assess the effects of lasalocid on earthworms (Eisenia andrei) and isopods (Porcellio scaber) and compared the results with tests using avoidance behaviour as the endpoint. The results showed that avoidance is a much more sensitive endpoint. For earthworms, EC50 for avoidance (12.3 mg kg(-1) dry soil) was more than five times lower than EC50 for reproduction (69.6 mg kg(-1) dry soil). In isopods the sensitivity of the behavioural response test was even higher. While the highest lasalocid concentration 202 mg kg(-1) had no significant effects on isopod growth or survival, already the lowest used concentration in the behavioural assay (4.51 mg kg(-1)) caused significant impact on isopod behaviour. Using the avoidance test results for calculating the predicted no-effect concentration (PNEC) of lasalocid to soil invertebrates, the value is close to the predicted environmental concentration (PEC). This indicates that the use of lasalocid-contaminated manure could potentially impair the habitat function of agricultural soils.

  20. Effect of Pakistani medicinal plants on IgE/antigen- and ionophore-induced mucosal mast cells degranulation.

    Science.gov (United States)

    Zaidi, Syed Faisal; Kim, Ji-Hyun; Tomoe, Yashiro; Usmanghani, Khan; Kadowaki, Makoto

    2014-07-01

    Cumulative evidence has now demonstrated the stimulation of mucosal mast cells by both allergic and non-allergic triggers and their inhibition as a potential therapeutic target in many diseases like food allergy and ulcerative colitis. Hence, we screened medicinal plants from Pakistan against antigen- and ionophore-induced degranulation of mucosal mast cells. Aqueous ethanol extracts were screened. IgE/antigen- and A23187-induced degranulation of mucosal-type murine bone marrow derived mast cells (mBMMCs) were screening assays and β-hexosaminidase released from degranulated mBMMCs was measured. Real time-polymerase chain reaction was employed to examine the expression of TNF-α and IL-4 mRNA. Acetoxychavicol acetate, was examined by degranulation assays and real time-PCR. Among the ten plants screened against IgE/antigen stimulated degranulation, five plants; Alpinia galangal, Mentha arvensis, Myrtus communis, Polygonum bistorta and Syzygium aromaticum demonstrated significant (pgalangal showed significant (pgalangal exhibited significant (pgalangal revealed significant suppression at 10 μg/ml against A23187-stimulated degranulation. Acetoxychavicol acetate demonstrated significant (pgalangal and acetoxychavicol acetate suppressed the IgE/antigen- and A23187-enhanced mRNA expression of inflammatory cytokines, TNF-a and IL-4, in mBMMCs. Our findings revealed the suppressive effect of Alpinia galangal and acetoxychavicol acetate on degranulation of mBMMCs by allergic and non-allergic stimuli, which can be utilized for future drug development against food allergy or ulcerative colitis.

  1. Live birth after artificial oocyte activation using a ready-to-use ionophore: a prospective multicentre study.

    Science.gov (United States)

    Ebner, Thomas; Montag, Markus; Montag, M; Van der Ven, K; Van der Ven, H; Ebner, T; Shebl, O; Oppelt, P; Hirchenhain, J; Krüssel, J; Maxrath, B; Gnoth, C; Friol, K; Tigges, J; Wünsch, E; Luckhaus, J; Beerkotte, A; Weiss, D; Grunwald, K; Struller, D; Etien, C

    2015-04-01

    Artificial oocyte activation has been proposed as a suitable means to overcome the problem of failed or impaired fertilization after intracytoplasmic sperm injection (ICSI). In a multicentre setting artificial oocyte activation was applied to 101 patients who were diagnosed with fertilization abnormalities (e.g. less than 50% fertilized oocytes) in a previous conventional ICSI cycle. Female gametes were activated for 15 min immediately after ICSI using a ready-to-use Ca(2+)-ionophore solution (A23187). Fertilization, pregnancy and live birth rates were compared with the preceding cycle without activation. The fertilization rate of 48% in the study cycles was significantly higher compared with the 25% in the control cycles (P splitting of the historical control group into failed (0%), low (1-30%) and moderate fertilization rate (31-50%) showed that all groups significantly benefitted (P embryo transfer cancelled compared with their previous treatments (1/101 versus 15/101). In total, 99% of the patients had an improved outcome with A23187 application resulting in a 28% live birth rate (35 babies). These data suggest that artificial oocyte activation using a ready-to-use compound is an efficient method.

  2. WE-G-BRD-06: Volumetric Cine MRI (VC-MRI) Estimated Based On Prior Knowledge for On-Board Target Localization

    Energy Technology Data Exchange (ETDEWEB)

    Harris, W; Yin, F; Cai, J; Zhang, Y; Ren, L [Duke University Medical Center, Durham, NC (United States)

    2015-06-15

    Purpose: To develop a technique to generate on-board VC-MRI using patient prior 4D-MRI, motion modeling and on-board 2D-cine MRI for real-time 3D target verification of liver and lung radiotherapy. Methods: The end-expiration phase images of a 4D-MRI acquired during patient simulation are used as patient prior images. Principal component analysis (PCA) is used to extract 3 major respiratory deformation patterns from the Deformation Field Maps (DFMs) generated between end-expiration phase and all other phases. On-board 2D-cine MRI images are acquired in the axial view. The on-board VC-MRI at any instant is considered as a deformation of the prior MRI at the end-expiration phase. The DFM is represented as a linear combination of the 3 major deformation patterns. The coefficients of the deformation patterns are solved by matching the corresponding 2D slice of the estimated VC-MRI with the acquired single 2D-cine MRI. The method was evaluated using both XCAT (a computerized patient model) simulation of lung cancer patients and MRI data from a real liver cancer patient. The 3D-MRI at every phase except end-expiration phase was used to simulate the ground-truth on-board VC-MRI at different instances, and the center-tumor slice was selected to simulate the on-board 2D-cine images. Results: Image subtraction of ground truth with estimated on-board VC-MRI shows fewer differences than image subtraction of ground truth with prior image. Excellent agreement between profiles was achieved. The normalized cross correlation coefficients between the estimated and ground-truth in the axial, coronal and sagittal views for each time step were >= 0.982, 0.905, 0.961 for XCAT data and >= 0.998, 0.911, 0.9541 for patient data. For XCAT data, the maximum-Volume-Percent-Difference between ground-truth and estimated tumor volumes was 1.6% and the maximum-Center-of-Mass-Shift was 0.9 mm. Conclusion: Preliminary studies demonstrated the feasibility to estimate real-time VC-MRI for on

  3. Can an intervention based on a serious videogame prior to cognitive behavioral therapy be helpful in bulimia nervosa? A clinical case study.

    Directory of Open Access Journals (Sweden)

    Cristina eGiner-Bartolomé

    2015-07-01

    Full Text Available Background: Several studies have highlighted the implications of impulsivity and novelty seeking for both the maintenance and the process of recovery from bulimia nervosa. Cognitive behavioral therapy (CBT is the treatment of choice for bulimia nervosa, but for some cases, this treatment alone might not be sufficient for reducing the high levels of impulsivity. The paper presents a case report of a patient with bulimia nervosa, examining the effectiveness of using a videogame (Playmancer as an additional intervention designed to address impulsivity. Design: Psychometric and neuropsychological measures were collected at baseline. After this assessment, Playmancer was applied prior to CBT, following an A-B-A-C-A single case experimental design. Impulsivity levels were assessed with the Conners’ Continuous Performance Test II (CPT-II. After the Playmancer treatment, the patient started CBT, and the levels of impulsivity were recorded again. Finally, psychometric and neuropsychological measures were collected after treatment. Weekly frequency of binges and vomiting were also recorded during the entire procedure. Results: After the videogame intervention, psychometric measures such as anxiety levels, impulsivity and novelty seeking decreased. Regarding the neuropsychological measures, impulsivity levels (measured with the CPT-II progressively decreased throughout the intervention, and an improvement in decision making capacities was observed. Furthermore, the frequency of binges also decreased during and after the videogame intervention. Discussion: This case report suggests that using the Playmancer videogame to reduce impulsivity prior to CBT may enhance the final results of the treatment for bulimia nervosa.

  4. Novel LTCC-potentiometric microfluidic device for biparametric analysis of organic compounds carrying plastic antibodies as ionophores: application to sulfamethoxazole and trimethoprim.

    Science.gov (United States)

    Almeida, S A A; Arasa, E; Puyol, M; Martinez-Cisneros, C S; Alonso-Chamarro, J; Montenegro, M C B S M; Sales, M G F

    2011-12-15

    Monitoring organic environmental contaminants is of crucial importance to ensure public health. This requires simple, portable and robust devices to carry out on-site analysis. For this purpose, a low-temperature co-fired ceramics (LTCC) microfluidic potentiometric device (LTCC/μPOT) was developed for the first time for an organic compound: sulfamethoxazole (SMX). Sensory materials relied on newly designed plastic antibodies. Sol-gel, self-assembling monolayer and molecular-imprinting techniques were merged for this purpose. Silica beads were amine-modified and linked to SMX via glutaraldehyde modification. Condensation polymerization was conducted around SMX to fill the vacant spaces. SMX was removed after, leaving behind imprinted sites of complementary shape. The obtained particles were used as ionophores in plasticized PVC membranes. The most suitable membrane composition was selected in steady-state assays. Its suitability to flow analysis was verified in flow-injection studies with regular tubular electrodes. The LTCC/μPOT device integrated a bidimensional mixer, an embedded reference electrode based on Ag/AgCl and an Ag-based contact screen-printed under a micromachined cavity of 600 μm depth. The sensing membranes were deposited over this contact and acted as indicating electrodes. Under optimum conditions, the SMX sensor displayed slopes of about -58.7 mV/decade in a range from 12.7 to 250 μg/mL, providing a detection limit of 3.85 μg/mL and a sampling throughput of 36 samples/h with a reagent consumption of 3.3 mL per sample. The system was adjusted later to multiple analyte detection by including a second potentiometric cell on the LTCC/μPOT device. No additional reference electrode was required. This concept was applied to Trimethoprim (TMP), always administered concomitantly with sulphonamide drugs, and tested in fish-farming waters. The biparametric microanalyzer displayed Nernstian behaviour, with average slopes -54.7 (SMX) and +57.8 (TMP) m

  5. Accommodating Uncertainty in Prior Distributions

    Energy Technology Data Exchange (ETDEWEB)

    Picard, Richard Roy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Vander Wiel, Scott Alan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-01-19

    A fundamental premise of Bayesian methodology is that a priori information is accurately summarized by a single, precisely de ned prior distribution. In many cases, especially involving informative priors, this premise is false, and the (mis)application of Bayes methods produces posterior quantities whose apparent precisions are highly misleading. We examine the implications of uncertainty in prior distributions, and present graphical methods for dealing with them.

  6. Validity in assessment of prior learning

    DEFF Research Database (Denmark)

    Wahlgren, Bjarne; Aarkrog, Vibe

    2015-01-01

    The article deals with the results of a study of school-based assessment of adults who have enrolled as students at a vocational college in order to qualify for occupations as skilled workers. Based on examples of methods for assessing the students’ prior learning in a programme for hairdressers...

  7. Validity in assessment of prior learning

    DEFF Research Database (Denmark)

    Wahlgren, Bjarne; Aarkrog, Vibe

    2015-01-01

    The article deals with the results of a study of school-based assessment of adults who have enrolled as students at a vocational college in order to qualify for occupations as skilled workers. Based on examples of methods for assessing the students’ prior learning in a programme for hairdressers...

  8. Social structure in a family group of Guanaco (Lama guanicoe, Ungulate): is female hierarchy based on 'prior attributes' or 'social dynamics'?

    Science.gov (United States)

    Correa, Loreto A; Zapata, Beatriz; Samaniego, Horacio; Soto-Gamboa, Mauricio

    2013-09-01

    Social life involves costs and benefits mostly associated with how individuals interact with each other. The formation of hierarchies inside social groups has evolved as a common strategy to avoid high costs stemming from social interactions. Hierarchical relationships seem to be associated with different features such as body size, body condition and/or age, which determine dominance ability ('prior attributes' hypothesis). In contrast, the 'social dynamic' hypothesis suggests that an initial social context is a determinant in the formation of the hierarchy, more so than specific individual attributes. Hierarchical rank places individuals in higher positions, which presumably increases resource accessibility to their benefit, including opportunities for reproduction. We evaluate the maintenance of hierarchy in a family group of guanacos (Lama guanicoe) and evaluate the possible mechanisms involved in the stability of these interactions and their consequences. We estimate the linearity of social hierarchy and their dynamics. We find evidence of the formation of a highly linear hierarchy among females with males positioned at the bottom of the hierarchy. This hierarchy is not affected by physical characteristics or age, suggesting that it is established only through intra-group interactions. Rank is not related with calves' weight gain either; however, subordinated females, with lower rank, exhibit higher rates of allosuckling. We found no evidence of hierarchical structure in calves suggesting that hierarchical relationship in guanacos could be established during the formation of the family group. Hence, our results suggest that hierarchical dynamics could be related more to social dynamics than to prior attributes. We finally discuss the importance of hierarchies established by dominance and their role in minimizing social costs of interactions. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Varying prior information in Bayesian inversion

    Science.gov (United States)

    Walker, Matthew; Curtis, Andrew

    2014-06-01

    Bayes' rule is used to combine likelihood and prior probability distributions. The former represents knowledge derived from new data, the latter represents pre-existing knowledge; the Bayesian combination is the so-called posterior distribution, representing the resultant new state of knowledge. While varying the likelihood due to differing data observations is common, there are also situations where the prior distribution must be changed or replaced repeatedly. For example, in mixture density neural network (MDN) inversion, using current methods the neural network employed for inversion needs to be retrained every time prior information changes. We develop a method of prior replacement to vary the prior without re-training the network. Thus the efficiency of MDN inversions can be increased, typically by orders of magnitude when applied to geophysical problems. We demonstrate this for the inversion of seismic attributes in a synthetic subsurface geological reservoir model. We also present results which suggest that prior replacement can be used to control the statistical properties (such as variance) of the final estimate of the posterior in more general (e.g., Monte Carlo based) inverse problem solutions.

  10. Menarche: Prior Knowledge and Experience.

    Science.gov (United States)

    Skandhan, K. P.; And Others

    1988-01-01

    Recorded menstruation information among 305 young women in India, assessing the differences between those who did and did not have knowledge of menstruation prior to menarche. Those with prior knowledge considered menarche to be a normal physiological function and had a higher rate of regularity, lower rate of dysmenorrhea, and earlier onset of…

  11. The Importance of Prior Knowledge.

    Science.gov (United States)

    Cleary, Linda Miller

    1989-01-01

    Recounts a college English teacher's experience of reading and rereading Noam Chomsky, building up a greater store of prior knowledge. Argues that Frank Smith provides a theory for the importance of prior knowledge and Chomsky's work provided a personal example with which to interpret and integrate that theory. (RS)

  12. The Importance of Prior Knowledge.

    Science.gov (United States)

    Cleary, Linda Miller

    1989-01-01

    Recounts a college English teacher's experience of reading and rereading Noam Chomsky, building up a greater store of prior knowledge. Argues that Frank Smith provides a theory for the importance of prior knowledge and Chomsky's work provided a personal example with which to interpret and integrate that theory. (RS)

  13. Steroid modulation of the chloride ionophore in rat brain: structure-activity requirements, regional dependence and mechanism of action

    Energy Technology Data Exchange (ETDEWEB)

    Gee, K.W.; Bolger, M.B.; Brinton, R.E.; Coirini, H.; McEwen, B.S.

    1988-08-01

    Further in vitro studies of steroids active at the gamma-aminobutyric acidA (GABAA) receptor regulated Cl- channel labeled by (35S)-t-butylbicyclophosphorothionate ((35S)TBPS) reveal additional structural requirements necessary for activity. Evaluation of selected steroids for activity against TBPS-induced convulsions show similar requirements for activity. Interestingly, steroids (e.g., 5 alpha-pregnan-3 alpha, 20 alpha-diol) were identified that have high potency but limited efficacy as modulators of (35S)TBPS binding. These characteristics are reminiscent of the clinically useful benzodiazepines (BZs) such as clonazepam. However, interactions between the prototypical anesthetic-barbiturate, sodium pentobarbital, and steroids active at the Cl- channel suggest that they do not share a common site of action as allosteric modulators of (35S)TBPS and BZ receptor binding. The most potent steroid evaluated, 5 alpha-pregnan-3 alpha-ol-20-one, modulates (35S)TBPS binding at low concentrations (IC50 approximately 17 nM) in a regionally dependent manner. All (35S)TBPS binding sites appear to be functionally coupled to a steroid modulatory site. Because several of the active steroids are metabolites of progesterone, their ability to inhibit the binding of (3H)promegestrone to the cytosolic progestin receptor in rat uterus was evaluated. Those steroids showing potent activity at the GABAA receptor-Cl- ionophore were inactive at the intracellular progestin receptor. Such specificity coupled with their high potency provide additional support for the hypothesis that some of these steroids may be involved in the homeostatic regulation of brain excitability via the GABAA-BZ receptor complex.

  14. Possible scenarios for occurrence of M ~ 7 interplate earthquakes prior to and following the 2011 Tohoku-Oki earthquake based on numerical simulation

    Science.gov (United States)

    Nakata, Ryoko; Hori, Takane; Hyodo, Mamoru; Ariyoshi, Keisuke

    2016-05-01

    We show possible scenarios for the occurrence of M ~ 7 interplate earthquakes prior to and following the M ~ 9 earthquake along the Japan Trench, such as the 2011 Tohoku-Oki earthquake. One such M ~ 7 earthquake is so-called the Miyagi-ken-Oki earthquake, for which we conducted numerical simulations of earthquake generation cycles by using realistic three-dimensional (3D) geometry of the subducting Pacific Plate. In a number of scenarios, the time interval between the M ~ 9 earthquake and the subsequent Miyagi-ken-Oki earthquake was equal to or shorter than the average recurrence interval during the later stage of the M ~ 9 earthquake cycle. The scenarios successfully reproduced important characteristics such as the recurrence of M ~ 7 earthquakes, coseismic slip distribution, afterslip distribution, the largest foreshock, and the largest aftershock of the 2011 earthquake. Thus, these results suggest that we should prepare for future M ~ 7 earthquakes in the Miyagi-ken-Oki segment even though this segment recently experienced large coseismic slip in 2011.

  15. Possible scenarios for occurrence of M ~ 7 interplate earthquakes prior to and following the 2011 Tohoku-Oki earthquake based on numerical simulation.

    Science.gov (United States)

    Nakata, Ryoko; Hori, Takane; Hyodo, Mamoru; Ariyoshi, Keisuke

    2016-05-10

    We show possible scenarios for the occurrence of M ~ 7 interplate earthquakes prior to and following the M ~ 9 earthquake along the Japan Trench, such as the 2011 Tohoku-Oki earthquake. One such M ~ 7 earthquake is so-called the Miyagi-ken-Oki earthquake, for which we conducted numerical simulations of earthquake generation cycles by using realistic three-dimensional (3D) geometry of the subducting Pacific Plate. In a number of scenarios, the time interval between the M ~ 9 earthquake and the subsequent Miyagi-ken-Oki earthquake was equal to or shorter than the average recurrence interval during the later stage of the M ~ 9 earthquake cycle. The scenarios successfully reproduced important characteristics such as the recurrence of M ~ 7 earthquakes, coseismic slip distribution, afterslip distribution, the largest foreshock, and the largest aftershock of the 2011 earthquake. Thus, these results suggest that we should prepare for future M ~ 7 earthquakes in the Miyagi-ken-Oki segment even though this segment recently experienced large coseismic slip in 2011.

  16. Structured sparse priors for image classification.

    Science.gov (United States)

    Srinivas, Umamahesh; Suo, Yuanming; Dao, Minh; Monga, Vishal; Tran, Trac D

    2015-06-01

    Model-based compressive sensing (CS) exploits the structure inherent in sparse signals for the design of better signal recovery algorithms. This information about structure is often captured in the form of a prior on the sparse coefficients, with the Laplacian being the most common such choice (leading to l1 -norm minimization). Recent work has exploited the discriminative capability of sparse representations for image classification by employing class-specific dictionaries in the CS framework. Our contribution is a logical extension of these ideas into structured sparsity for classification. We introduce the notion of discriminative class-specific priors in conjunction with class specific dictionaries, specifically the spike-and-slab prior widely applied in Bayesian sparse regression. Significantly, the proposed framework takes the burden off the demand for abundant training image samples necessary for the success of sparsity-based classification schemes. We demonstrate this practical benefit of our approach in important applications, such as face recognition and object categorization.

  17. Prior Structural Information CT Reconstruction Algorithm Based on Variable Voltage%基于结构先验的变电压 CT 成像

    Institute of Scientific and Technical Information of China (English)

    张雪英; 陈平; 潘晋孝

    2015-01-01

    为获得更高质量的CT重建图像,建立了基于结构先验的变电压CT成像方法。该方法对同一像素点在不同电压下满足最佳灰度带的有效投影数据进行叠加迭代重建,得到递变电压的重建结果,通过设定阈值,将低电压下投影数据的重建结果分为两个部分,将边缘的结构部分先验地运用到高电压下投影数据的重建结果里,以此弥补变电压重建图像过程中的信息缺失。仿真实验表明:该方法能够获得完整的工件信息,重建图像质量高,像素值也更加稳定。%The method of variable voltage CT reconstruction is to obtain projection sequence matching the effec -tive thickness of work piece under variable voltage and to construct it .Firstly, we use the efficient projection of the same pixel under different voltages meeting the best condition to reconstruct .So we can get variable voltage reconstruction .Then by setting threshold , the reconstruction of the projection data under low voltage can be di-vided into an edge portion and a non -edge section and the edge portion priors to applying to the reconstruction of the projection data under high voltage in order to make up for the missing information .Experiment shows that that this method can obtain the complete information of work piece , the quality of reconstructed image is higher and the pixel values are more stable .

  18. Economic value of ionophores and propylene glycol to prevent disease and treat ketosis in Canada.

    Science.gov (United States)

    Gohary, Khaled; Overton, Michael W; Von Massow, Michael; LeBlanc, Stephen J; Lissemore, Kerry D; Duffield, Todd F

    2016-07-01

    A partial budget model was developed to evaluate the economic value of Rumensin Controlled Release Capsule (CRC) boluses when administered before calving to reduce disease and increase milk production. After accounting for disease incidences in a herd and the percentage by which Rumensin CRC can reduce them, and the increase in milk production attributable to administration of Rumensin CRC, the return on investment (ROI) per lactation was 4:1. Another partial budget model was developed to estimate the economic value of propylene glycol (PG) to treat ketosis when diagnosed by 3 different cow-side tests or when administered to all cows without using any cow-side testing. After accounting for the sensitivity and specificity of each test, ROI per lactation ranged from 2:1 to 4:1. The ROI was 2:1 when no cow-side testing was used. In conclusion, prevention of diseases that occur in the postpartum period and treatment of ketosis after calving yielded a positive ROI that varies based on disease incidence and method of diagnosis.

  19. Universal Prior Prediction for Communication

    CERN Document Server

    Lomnitz, Yuval

    2011-01-01

    We consider the problem of communicating over an unknown and arbitrarily varying channel, using feedback. This paper focuses on the problem of determining the input behavior, or more specifically, a prior which is used to randomly generate a codebook. We pose the problem of setting the prior as a universal sequential prediction problem using information theoretic abstractions of the communication channel. For the case where the channel is block-wise constant, we show it is possible to asymptotically approach the best rate that can be attained by any system using a fixed prior. For the case where the channel may change on each symbol, we combine a rateless coding scheme with a prior predictor and asymptotically approach the capacity of the average channel universally for every sequence of channels.

  20. Recruiting for Prior Service Market

    Science.gov (United States)

    2008-06-01

    perceptions, expectations and issues for re-enlistment • Develop potential marketing and advertising tactics and strategies targeted to the defined...01 JUN 2008 2. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE Recruiting for Prior Service Market 5a. CONTRACT NUMBER 5b. GRANT...Command First Handshake to First Unit of Assignment An Army of One Proud to Be e e to Serve Recruiting for Prior Service Market MAJ Eric Givens / MAJ Brian

  1. Investigating the Effectiveness of an Inquiry-Based Intervention on Human Reproduction in Relation to Students' Gender, Prior Knowledge and Motivation for Learning in Biology

    Science.gov (United States)

    Hadjichambis, Andreas Ch.; Georgiou, Yiannis; Paraskeva-Hadjichambi, Demetra; Kyza, Eleni A.; Mappouras, Demetrios

    2016-01-01

    Despite the importance of understanding how the human reproductive system works, adolescents worldwide exhibit weak conceptual understanding, which leads to serious risks, such as unwanted pregnancies and sexually transmitted diseases. Studies focusing on the development and evaluation of inquiry-based learning interventions, promoting the…

  2. Investigating the Effectiveness of an Inquiry-Based Intervention on Human Reproduction in Relation to Students' Gender, Prior Knowledge and Motivation for Learning in Biology

    Science.gov (United States)

    Hadjichambis, Andreas Ch.; Georgiou, Yiannis; Paraskeva-Hadjichambi, Demetra; Kyza, Eleni A.; Mappouras, Demetrios

    2016-01-01

    Despite the importance of understanding how the human reproductive system works, adolescents worldwide exhibit weak conceptual understanding, which leads to serious risks, such as unwanted pregnancies and sexually transmitted diseases. Studies focusing on the development and evaluation of inquiry-based learning interventions, promoting the…

  3. Ionophores in the Environment

    DEFF Research Database (Denmark)

    Bak, Søren Alex; Hansen, Martin; Björklund, Erland

    Questions have arisen about the effects of veterinary medicines and especially their metabolites have on organisms in the environment. A couple of recent investigations has further reported that metabolites of certain veterinary drugs such as antibacterial agents (i.e. tetracyclines) and antipara......-001-0017-2 Hansen M, Krogh KA, Brandt A, Christensen JH, Halling-Sorensen B (2009) Environmental Pollution 157: 2 p. 474-480. DOI:10.1016/j.envpol.2008.09.022...

  4. A DFT based analysis of adsorption of Hg(2+) ion on chitosan monomer and its citralidene and salicylidene derivatives: Prior to the removal of Hg toxicity.

    Science.gov (United States)

    Hassan, Basila; Rajan, Vijisha K; Mujeeb, V M Abdul; K, Muraleedharan

    2017-03-07

    A Density functional theory based study of adsorption of the toxic metal Hg (II) ion by chitosan monomer and two of its derivatives; citralidene and salicylidene chitosan, has been performed. The effect of structural features on the stability of studied complexes has been analyzed by using Gaussian03 software package. All the possible conformations of these adsorbents were studied using the global minimum geometries. All the adsorbing sites were studied by placing the metal ion on the centroid of the atoms and the stable conformer of the adsorbent-metal ion complex was identified. Interaction between Hg (II) and the adsorbents is found to be electrostatic. Metal ion binding with nitrogen atom is stronger than that with oxygen atoms in all the cases as the charge density of nitrogen is enhanced on Schiff base formation. The advantage of derivatives over chitosan monomer is their stability in acidic media. ΔE value of the complexes are in the order SC-Hg (II)>chitosan-Hg (II)>CC-Hg (II) which indicates that the stability of complexes increases with increase in energy gap. The study reveals that aromatic Schiff base derivatives of chitosan is better for Hg(II) intake than aliphatic derivatives.

  5. Flow-injection potentiometry by poly(vinyl chloride)-membrane electrodes with diphosphoryl-dicarboxylicacid-p-tert-butylcalix[4]arene ionophore for the determination of Th(IV) ions.

    Science.gov (United States)

    Mizani, Farhang; Shamsipur, Mojtaba; Yaftian, Mohammad R; Matt, Dominique

    2013-01-01

    A new coated ion-selective electrode for the determination of trace thorium ions by flow-injection potentiometry (FIP) has been developed. A poly(vinyl chloride) (PVC)-based membrane was coated on a graphite electrode. The optimum membrane contained 5 wt% diphosphoryl-dicarboxylicacid-p-tert-butylcalix[4]arene (L) as the ionophore, 59 wt% dioctyl phthalate (DOP), 33 wt% PVC and 3 wt% additive sodium tetraphenylborate. The response was linear from 2.0 × 10(-7) to 1.0 × 10(-2) M with a slope of 13.9 mV decade(-1) and a limit of detection of 9.0 × 10(-8) M. The pH-independent region ranged from 3.15 to 6.5, and the lifetime was longer than 8 weeks when used in the flow injection analysis (FIA) system. Selectivity coefficients for several ions were obtained by the separate solutions method. Results showed that, for all cations used, the selectivity coefficients were in the order of 10(-3), or smaller. The flow cell is simple to construct and free from memory effect problems over long periods of use. The proposed sensor was successfully applied to the direct determination of thorium in both real and synthetic samples.

  6. Extension of Viscoplasticity Based on Overstress to Capture the Effects of Prior Aging on the Time Dependent Deformation Behavior of a High-Temperature Polymer: Experiments and Modeling

    Science.gov (United States)

    2008-10-01

    4.8. Effect of I Gain on System Response . . . . . . . . . . . . . . . 62 4.9. Strain Control Tuning with PMR-15 and Low Contact Force Ex- tensometer ...with PMR-15 and Low Contact Force Ex- tensometer : Loading and Unloading in Strain Control at 288 ◦C. Strain Rate is 10−3 s−1...were characterized by Falcone based on her experimental data on PMR-15. As part of 19 Figure 2.4: Stress-Strain Response in a Stepwise Creep Test of

  7. Bayesian priors for transiting planets

    CERN Document Server

    Kipping, David M

    2016-01-01

    As astronomers push towards discovering ever-smaller transiting planets, it is increasingly common to deal with low signal-to-noise ratio (SNR) events, where the choice of priors plays an influential role in Bayesian inference. In the analysis of exoplanet data, the selection of priors is often treated as a nuisance, with observers typically defaulting to uninformative distributions. Such treatments miss a key strength of the Bayesian framework, especially in the low SNR regime, where even weak a priori information is valuable. When estimating the parameters of a low-SNR transit, two key pieces of information are known: (i) the planet has the correct geometric alignment to transit and (ii) the transit event exhibits sufficient signal-to-noise to have been detected. These represent two forms of observational bias. Accordingly, when fitting transits, the model parameter priors should not follow the intrinsic distributions of said terms, but rather those of both the intrinsic distributions and the observational ...

  8. Comprehensive evaluation of two HLA-B17 monoclonal antibodies for flow cytometry-based HLA-B57/B58 screening prior to abacavir prescription.

    Science.gov (United States)

    Stevens, R; Coates, E; Street, J; Cook, E; Darke, C

    2013-08-01

    Hypersensitivity reactions to the drug abacavir, used to treat HIV/AIDS patients, is associated with possession of HLA-B*57:01. We have carefully assessed two commercially available HLA-B57/B58 murine monoclonal antibodies [0196HA and BIH0243 (One Lambda Inc.)] in a simple flow cytometry-based assay. The evaluation involved tests on 228 reference and random samples covering 91% of all WHO recognized HLA-A, B and C specificities. These involved donors with six different HLA-B*57 alleles and included 19 examples of B*57:01. Both antibodies unambiguously detected B57, but there were small difference in their reactivity against B57-positive non-B*57:01 samples. Importantly, there was no reactivity against B57/B58-negative samples. The possible amino acid motifs involved in the reactivity of these antibodies with B57/B58 were delineated. Thus, HLA-B57/B58, normally present in <10% of patients, can be easily recognized using these two antibodies and further tested by a DNA-based typing method to identify B*57:01.

  9. Arthur Prior and medieval logic

    OpenAIRE

    2012-01-01

    Though Arthur Prior is now best known for his founding of modern temporal logic and hybrid logic, much of his early philosophical career was devoted to history of logic and historical logic. This interest laid the foundations for both of his ground-breaking innovations in the 1950s and 1960s. Because of the important rôle played by Prior’s research in ancient and medieval logic in his development of temporal and hybrid logic, any student of Prior, temporal logic, or hybrid logic should be fam...

  10. The Clinical and Cost Effectiveness of Aflibercept in Combination with Irinotecan and Fluorouracil-Based Therapy (FOLFIRI) for the Treatment of Metastatic Colorectal Cancer Which has Progressed Following Prior Oxaliplatin-Based Chemotherapy: a Critique of the Evidence.

    Science.gov (United States)

    Wade, Ros; Duarte, Ana; Simmonds, Mark; Rodriguez-Lopez, Rocio; Duffy, Steven; Woolacott, Nerys; Spackman, Eldon

    2015-05-01

    The National Institute for Health and Care Excellence (NICE) invited the manufacturer of aflibercept (Sanofi) to submit clinical and cost-effectiveness evidence for aflibercept in combination with irinotecan and fluorouracil-based therapy [irinotecan/5-fluorouracil/folinic acid (FOLFIRI)] for the treatment of metastatic colorectal cancer which has progressed following prior oxaliplatin-based chemotherapy, as part of the Institute's Single Technology Appraisal process. The Centre for Reviews and Dissemination and Centre for Health Economics at the University of York were commissioned to act as the independent Evidence Review Group (ERG). This article provides a description of the company submission, the ERG review and the resulting NICE guidance TA307 issued in March 2014. The ERG critically reviewed the evidence presented in the manufacturer's submission and identified areas requiring clarification, for which the manufacturer provided additional evidence. The clinical effectiveness data were derived from one good-quality double-blind randomised controlled trial (RCT), the VELOUR trial, which compared aflibercept plus FOLFIRI with placebo plus FOLFIRI. This RCT found a small but statistically significant increase in overall survival (OS); the difference in median OS was 1.44 months (13.5 months in the aflibercept group and 12.06 months in the placebo group). There was also a statistically significant increase in progression-free survival (PFS) with aflibercept; the difference in median PFS was 2.23 months (6.9 months in the aflibercept group and 4.67 months in the placebo group). However, grade 3-4 adverse events were more frequent in the aflibercept group than the placebo group: 83.5% compared with 62.5%. Treatment-emergent adverse events led to permanent discontinuation of treatment in 26.8% of patients in the aflibercept group and 12.1% of patients in the placebo group. The manufacturer's submission included an estimation of mean OS benefit based on extrapolation

  11. Components of Visual Prior Entry

    Science.gov (United States)

    Schneider, Keith A.; Bavelier, Daphne

    2003-01-01

    The prior entry hypothesis contends that attention accelerates sensory processing, shortening the time to perception. Typical observations supporting the hypothesis may be explained equally well by response biases, changes in decision criteria, or sensory facilitation. In a series of experiments conducted to discriminate among the potential…

  12. Arthur Prior and medieval logic

    NARCIS (Netherlands)

    Uckelman, S.L.

    2012-01-01

    Though Arthur Prior is now best known for his founding of modern temporal logic and hybrid logic, much of his early philosophical career was devoted to history of logic and historical logic. This interest laid the foundations for both of his ground-breaking innovations in the 1950s and 1960s. Becaus

  13. Population-Based Lynch Syndrome Screening by Microsatellite Instability in Patients ≤50: Prevalence, Testing Determinants, and Result Availability Prior to Colon Surgery.

    Science.gov (United States)

    Karlitz, Jordan J; Hsieh, Mei-Chin; Liu, Yong; Blanton, Christine; Schmidt, Beth; Jessup, J Milburn; Wu, Xiao-Cheng; Chen, Vivien W

    2015-07-01

    As there are no US population-based studies examining Lynch syndrome (LS) screening frequency by microsatellite instability (MSI) and immunohistochemistry (IHC), we seek to quantitate statewide rates in patients aged ≤50 years using data from a Centers for Disease Control and Prevention-funded Comparative Effectiveness Research (CER) project and identify factors associated with testing. Screening rates in this young, high-risk population may provide a best-case scenario as older patients, potentially deemed lower risk, may undergo testing less frequently. We also seek to determine how frequently MSI/IHC results are available preoperatively, as this may assist with decisions regarding colonic resection extent. Data from all Louisiana colorectal cancer (CRC) patients aged ≤50 years diagnosed in 2011 were obtained from the Louisiana Tumor Registry CER project. Registry researchers and physicians analyzed data, including pathology and MSI/IHC. Of the 2,427 statewide all-age CRC patients, there were 274 patients aged ≤50 years, representing health care at 61 distinct facilities. MSI and/or IHC were performed in 23.0% of patients. Testing-associated factors included CRC family history (Plocation (P<0.0370), and care at comprehensive cancer centers (P<0.0020) but not synchronous/metachronous CRC or MSI-like histology. Public hospital screening was disproportionately low (P<0.0217). Of those tested, MSI and/or IHC was abnormal in 21.7%. Of those with abnormal IHC, staining patterns were consistent with LS in 87.5%. MSI/IHC results were available preoperatively in 16.9% of cases. Despite frequently abnormal MSI/IHC results, LS screening in young, high-risk patients is low. Provider education and disparities in access to specialized services, particularly in underserved populations, are possible contributors. MSI/IHC results are infrequently available preoperatively.

  14. Fast image de-hazing method based on improved dark channel prior model%基于改进暗原色先验模型的快速图像去雾方法

    Institute of Scientific and Technical Information of China (English)

    杜宏博; 王丽会

    2016-01-01

    To deal with the image degradation problem induced by the haze or fog, a fast image de-hazing algorithm based on an improved dark channel prior model and tolerance mechanism is proposed. The atmosphere light is firstly estimated using dark channels, and then for calculating accurately the transmission map of the image with different scene depths, the dark channel prior model is improved by combining the interpolation and the minimum-maximum estimation methods, finally the de-hazing image is restored using the tolerance mechanism and atmospheric scatting model. The experimental results illustrate that, comparing with the original de-hazing methods based on dark channel prior, the proposed algorithm is very fast with a computation time reduced to 1/30 and effective for fog removal in both dark and light image areas. The improved dark channel prior model by combining interpolation and minimum-maximum estimation methods has a potential for real-time and robust image de-hazing.%为了解决雾天图像质量退化问题,结合改进的暗原色原理与容差机制提出一种快速图像去雾算法.该算法首先基于暗原色先验估计大气参数,然后利用插值算法和最大最小估计法改进暗原色先验模型进而准确计算出不同场景深度的透射率,最后结合容差机制基于大气散射模型恢复无雾图像.实验结果表明,相比于原有的暗原色先验算法,该算法的计算速度可提高至少30倍,并且能够同时实现明亮与暗色区域的有效去雾,去雾图像清晰自然.基于插值算法与最大最小估计法改进的暗原色先验去雾模型可同时保证去雾处理的鲁棒性和实时性.

  15. A calixarene-based ion-selective electrode for thallium(I) detection

    Energy Technology Data Exchange (ETDEWEB)

    Chester, Ryan [Nanochemistry Research Institute, Department of Chemistry, Curtin University, GPO Box U1987, Perth, Western Australia 6845 (Australia); Sohail, Manzar [Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Locked Bag 4, Maroochydore DC, Queensland 4556 (Australia); Ogden, Mark I.; Mocerino, Mauro [Nanochemistry Research Institute, Department of Chemistry, Curtin University, GPO Box U1987, Perth, Western Australia 6845 (Australia); Pretsch, Ernö [ETH Zürich, Institute of Biogeochemistry and Pollutant Dynamics (IBP), Universitätstrasse 16, CH-8092, Zürich (Switzerland); De Marco, Roland, E-mail: rdemarc1@usc.edu.au [Nanochemistry Research Institute, Department of Chemistry, Curtin University, GPO Box U1987, Perth, Western Australia 6845 (Australia); Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Locked Bag 4, Maroochydore DC, Queensland 4556 (Australia)

    2014-12-03

    Highlights: • Tuning of metal binding cavities in thallium(I) calixarene ionophores. • Novel calixarene-based ionophores with improved selectivity for thallium(I). • Sandwich membrane characterization of thallium(I) binding in novel calixarenes. • Improved selectivity and sensitivity with novel thallium(I) calixarene ionophores. • Solid contact ion-selective electrodes for novel thallium(I) calixarene ionophores. - Abstract: Three new calixarene Tl{sup +} ionophores have been utilized in Tl{sup +} ion-selective electrodes (ISEs) yielding Nernstian response in the concentration range of 10{sup −2}–10{sup −6} M TlNO{sub 3} with a non-optimized filling solution in a conventional liquid contact ISE configuration. The complex formation constants (log β{sub IL}) for two of the calixarene derivatives with thallium(I) (i.e. 6.44 and 5.85) were measured using the sandwich membrane technique, with the other ionophore immeasurable due to eventual precipitation of the ionophore during these long-term experiments. Furthermore, the unbiased selectivity coefficients for these ionophores displayed excellent selectivity against Zn{sup 2+}, Ca{sup 2+}, Ba{sup 2+}, Cu{sup 2+}, Cd{sup 2+} and Al{sup 3+} with moderate selectivity against Pb{sup 2+}, Li{sup +}, Na{sup +}, H{sup +}, K{sup +}, NH{sub 4}{sup +} and Cs{sup +}, noting that silver was the only significant interferent with these calixarene-based ionophores. When optimizing the filling solution in a liquid contact ISE, it was possible to achieve a lower limit of detection of approximately 8 nM according to the IUPAC definition. Last, the new ionophores were also evaluated in four solid-contact (SC) designs leading to Nernstian response, with the best response noted with a SC electrode utilizing a gold substrate, a poly(3-octylthiophene) (POT) ion-to-electron transducer and a poly(methyl methacrylate)–poly(decyl methacrylate) (PMMA–PDMA) co-polymer membrane. This electrode exhibited a slope of 58.4 mV decade

  16. Development of a new prior knowledge based image reconstruction algorithm for the cone-beam-CT in radiation therapy; Entwicklung eines neuen vorwissensbasierten Bildrekonstruktionsalgorithmus fuer die Cone-Beam-CT Bildgebung in der Strahlentherapie

    Energy Technology Data Exchange (ETDEWEB)

    Vaegler, Sven

    2016-07-08

    The treatment of cancer in radiation therapy is achievable today by techniques that enable highly conformal dose distributions and steep dose gradients. In order to avoid mistreatment, these irradiation techniques have necessitated enhanced patient localization techniques. With an integrated x-ray tube at modern linear accelerators kV-projections can be acquired over a sufficiently large angular space and can be reconstructed to a volumetric image data set from the current situation of the patient prior to irradiation. The so-called Cone-Beam-CT (CBCT) allows a precise verification of patient positioning as well as adaptive radiotherapy. The benefits of an improved patient positioning due to a daily performed CBCT's is contrary to an increased and not negligible radiation exposure of the patient. In order to decrease the radiation exposure, substantial research effort is focused on various dose reduction strategies. Prominent strategies are the decrease of the charge per projection, the reduction of the number of projections as well as the reduction of the acquisition space. Unfortunately, these acquisition schemes lead to images with degraded quality with the widely used Feldkamp-Davis-Kress image reconstruction algorithm. More sophisticated image reconstruction techniques can deal with these dose-reduction strategies without degrading the image quality. A frequently investigated method is the image reconstruction by minimizing the total variation (TV), which is also known as Compressed Sensing (CS). A Compressed Sensing-based reconstruction framework that includes prior images into the reconstruction algorithm is the Prior-Image-Constrained- Compressed-Sensing algorithm (PICCS). The images reconstructed by PICCS outperform the reconstruction results of the conventional Feldkamp-Davis-Kress algorithm (FDK) based method if only a small number of projections are available. However, a drawback of PICCS is that major deviations between prior image data sets and

  17. Method for Testability Demonstration Test Design Based on Entropy of Prior Test Information%基于验前试验信息熵的测试性验证试验方案

    Institute of Scientific and Technical Information of China (English)

    吴忠德; 邓露

    2016-01-01

    产品在研制阶段存在大量的试验数据,为有效利用验前数据,降低测试性验证试验样本量,提出一种基于验前试验信息熵的测试性验证试验方案。该方案利用信息熵来度量研制阶段多次验前试验数据对测试性验证试验所起的作用,依据平均互信息熵和信息总量相等的原则,将多次验前试验数据等效成一次成败型数据;在此基础上,通过相容性检验方法确定验前数据与试验数据的相容性水平,并以Beta分布为验前分布,利用加权混合贝叶斯理论建立混合验后分布,之后,基于贝叶斯平均风险理论求解满足双方风险要求的试验方案;最后,以某型雷达发射分机为例,对其进行测试性验证试验研究,研究结果验证了该方案的有效性。%In the development stage,there is a large number of test data.Aiming to making good use of the prior test data and reducing the sample number of testability demonstration test,a method for testability demonstration test design based on information entropy of prior test information is proposed.In the method information entropy is used to check the role of different prior test data for the testability demonstration test,and many times prior test data is equivalent to success or failure data at a time according to the principles of equal mean interactive entropy and equal total information. On this basis,compatibility of prior data and test data is established by the method of compatibility test,while Beta distribution is made use as prior distribution and the mixed posteriori distribution is established by weighted hybrid Bayesian theory.Then,testing scheme satisfying the risk require-ment of producer and consumer is solved based on Bayesian average risk theory.At last,to verify the proposed method,an example of a certain type of transmitter is given,and the result shows the validity of the proposed method.

  18. Prior Information in Inverse Boundary Problems

    DEFF Research Database (Denmark)

    Garde, Henrik

    This thesis gives a threefold perspective on the inverse problem of inclusion detection in electrical impedance tomography: depth dependence, monotonicitybased reconstruction, and sparsity-based reconstruction. The depth dependence is given in terms of explicit bounds on the datum norm, which shows...... into how much noise that can be allowed in the datum before an inclusion cannot be detected. The monotonicity method is a direct reconstruction method that utilizes a monotonicity property of the forward problem in order to characterize the inclusions. Here we rigorously prove that the method can...... of the method. Sparsity-based reconstruction is an iterative method, that through an optimization problem with a sparsity prior, approximates the inhomogeneities. Here we make use of prior information, that can cheaply be obtained from the monotonicity method, to improve both the contrast and resolution...

  19. Effects of prior stimulus and prior perception on neural correlates of auditory stream segregation.

    Science.gov (United States)

    Snyder, Joel S; Holder, W Trent; Weintraub, David M; Carter, Olivia L; Alain, Claude

    2009-11-01

    We examined whether effects of prior experience are mediated by distinct brain processes from those processing current stimulus features. We recorded event-related potentials (ERPs) during an auditory stream segregation task that presented an adaptation sequence with a small, intermediate, or large frequency separation between low and high tones (Deltaf), followed by a test sequence with intermediate Deltaf. Perception of two streams during the test was facilitated by small prior Deltaf and by prior perception of two streams and was accompanied by more positive ERPs. The scalp topography of these perception-related changes in ERPs was different from that observed for ERP modulations due to increasing the current Deltaf. These results reveal complex interactions between stimulus-driven activity and temporal-context-based processes and suggest a complex set of brain areas involved in modulating perception based on current and previous experience.

  20. Non-negative matrix factorization with Gaussian process priors

    DEFF Research Database (Denmark)

    Schmidt, Mikkel Nørgaard; Laurberg, Hans

    2008-01-01

    We present a general method for including prior knowledge in a nonnegative matrix factorization (NMF), based on Gaussian process priors. We assume that the nonnegative factors in the NMF are linked by a strictly increasing function to an underlying Gaussian process specified by its covariance...... function. This allows us to find NMF decompositions that agree with our prior knowledge of the distribution of the factors, such as sparseness, smoothness, and symmetries. The method is demonstrated with an example from chemical shift brain imaging....

  1. Spectrally Consistent Satellite Image Fusion with Improved Image Priors

    DEFF Research Database (Denmark)

    Nielsen, Allan Aasbjerg; Aanæs, Henrik; Jensen, Thomas B.S.;

    2006-01-01

    Here an improvement to our previous framework for satellite image fusion is presented. A framework purely based on the sensor physics and on prior assumptions on the fused image. The contributions of this paper are two fold. Firstly, a method for ensuring 100% spectrally consistency is proposed......, even when more sophisticated image priors are applied. Secondly, a better image prior is introduced, via data-dependent image smoothing....

  2. Non-negative matrix factorization with Gaussian process priors

    DEFF Research Database (Denmark)

    Schmidt, Mikkel Nørgaard; Laurberg, Hans

    2008-01-01

    We present a general method for including prior knowledge in a nonnegative matrix factorization (NMF), based on Gaussian process priors. We assume that the nonnegative factors in the NMF are linked by a strictly increasing function to an underlying Gaussian process specified by its covariance...... function. This allows us to find NMF decompositions that agree with our prior knowledge of the distribution of the factors, such as sparseness, smoothness, and symmetries. The method is demonstrated with an example from chemical shift brain imaging....

  3. Image Segmentation Using Weak Shape Priors

    CERN Document Server

    Xu, Robert Sheng; Salama, Magdy

    2010-01-01

    The problem of image segmentation is known to become particularly challenging in the case of partial occlusion of the object(s) of interest, background clutter, and the presence of strong noise. To overcome this problem, the present paper introduces a novel approach segmentation through the use of "weak" shape priors. Specifically, in the proposed method, an segmenting active contour is constrained to converge to a configuration at which its geometric parameters attain their empirical probability densities closely matching the corresponding model densities that are learned based on training samples. It is shown through numerical experiments that the proposed shape modeling can be regarded as "weak" in the sense that it minimally influences the segmentation, which is allowed to be dominated by data-related forces. On the other hand, the priors provide sufficient constraints to regularize the convergence of segmentation, while requiring substantially smaller training sets to yield less biased results as compare...

  4. The IVF Outcome Counseling Based on the Model Combining DHEAS and Age in Patients with Low AMH Prior to the First Cycle of GnRH Antagonist Protocol of Ovarian Stimulation

    Science.gov (United States)

    Alebić, Miro Šimun; Žuvić-Butorac, Marta

    2013-01-01

    Objective. To investigate the endocrine and/or clinical characteristics of women with low anti-Müllerian hormone (AMH) that could improve the accuracy of IVF outcome prediction based on the female age alone prior to the first GnRH antagonist IVF cycle. Methods. Medical records of 129 patients with low AMH level (5.7 pmol/L, 60% (9/15) of all pregnancies were achieved with CPR of 37.5%. Conclusions. DHEAS appears to be predictive for clinical pregnancy in younger women (<37.5 years) with low AMH after the first GnRH antagonist IVF cycle. Therefore, DHEAS-age model could refine the pretreatment counseling on pregnancy prospects following IVF. PMID:23509455

  5. Further observations on the utilization of adenosine triphosphate in rat mast cells during histamine release induced by the ionophore A23187

    DEFF Research Database (Denmark)

    Johansen, Torben

    1980-01-01

    1 The relation between A23187-induced histamine release and the energy metabolism of the rat mast cells has been studied. 2 Ethacrynic acid was used as an inhibitor of calcium-induced histamine release from mast cells primed with the ionophore A23187, and to study calcium-induced changes...... in the adenosine triphosphate (ATP) content and the rate of lactate production of A23187-primed mast cells. 3 Ethacrynic acid by itself decreased the rate of glycolytic ATP production. 4 By measurement of the ATP content and the lactate production of mast cells with or without secretory activity, the increased...... demand of energy for exocytosis was estimated to be equivalent to 0.14 pmol of ATP pr 10(3) mast cells....

  6. Designing conjoint choice experiments using managers' prior beliefs

    NARCIS (Netherlands)

    Sandor, Z; Wedel, M

    2001-01-01

    The authors provide more efficient designs for conjoint choice experiments based on prior information elicited from managers about the parameters and their associated uncertainty. The authors use a Bayesian design procedure that assumes a prior distribution of likely parameter values and optimizes

  7. Self-Assessment in University Assessment of Prior Learning Procedures

    Science.gov (United States)

    Brinke, D. Joosten-Ten; Sluijsmans, D. M. A.; Jochems, W. M. G.

    2009-01-01

    Competency-based university education, in which lifelong learning and flexible learning are key elements, demands a renewed vision on assessment. Within this vision, Assessment of Prior Learning (APL), in which learners have to show their prior learning in order for their goals to be recognised, becomes an important element. This article focuses…

  8. Perceptual Organization Algorithm with Global Cue Selection Based on Prior Model%基于先验模型的全局线索选择感知编组算法

    Institute of Scientific and Technical Information of China (English)

    周磊; 华钢; 徐钊; 徐冬梅

    2011-01-01

    Different perceptual organization (PO) algorithms focus on different global cues, so people have to firstly judge the object's global cue from the image,and then apply the corresponding PO algorithm. This paper proposed a PO algorithm with global cue selection based on prior model to automatically select the global cue with biggest probability. The prior model firstly obtained the prior knowledge and the sample distribution respectively from the statistical quantity of specific field and the generalized Laplacian distribution, then expressed the importance of each kind of global cues as the normalized information which was calculated by the posterior probability and the cue probability. To accelerate the computation,the grouping seed ranking method was incorporated. Finally, application of the algorithm in coal-mine field is analyzed. The results show this algorithm is efficient.%不同的感知编组(perceptual organization,PO)算法针对不同的全局线索,在使用中必须由人首先判定目标所满足的全局线索,之后选择相应的编组算法进行计算.本文提出基于先验模型的全局线索选择感知编组算法,可以从待选的多个全局线索中挑选出概率意义下最可能的线索作为编组依据.先验模型将场景的统计特性作为先验知识,以广义拉普拉斯分布作为样本的估计分布,通过后验概率和线索概率得到归一化信息量,以表达不同全局线索在编组过程中的重要程度.本文同时提出了编组种子的优先级排序算法,以加快计算速度.最后,以煤矿监控场景为例,说明了算法的计算过程,实验结果验证了算法的有效性.

  9. Testability evaluation using prior information of multiple sources

    Institute of Scientific and Technical Information of China (English)

    Wang Chao; Qiu Jing; Liu Guanjun; Zhang Yong

    2014-01-01

    Testability plays an important role in improving the readiness and decreasing the life-cycle cost of equipment. Testability demonstration and evaluation is of significance in measuring such testability indexes as fault detection rate (FDR) and fault isolation rate (FIR), which is useful to the producer in mastering the testability level and improving the testability design, and helpful to the consumer in making purchase decisions. Aiming at the problems with a small sample of testabil-ity demonstration test data (TDTD) such as low evaluation confidence and inaccurate result, a test-ability evaluation method is proposed based on the prior information of multiple sources and Bayes theory. Firstly, the types of prior information are analyzed. The maximum entropy method is applied to the prior information with the mean and interval estimate forms on the testability index to obtain the parameters of prior probability density function (PDF), and the empirical Bayesian method is used to get the parameters for the prior information with a success-fail form. Then, a parametrical data consistency check method is used to check the compatibility between all the sources of prior information and TDTD. For the prior information to pass the check, the prior credibility is calculated. A mixed prior distribution is formed based on the prior PDFs and the corresponding credibility. The Bayesian posterior distribution model is acquired with the mixed prior distribution and TDTD, based on which the point and interval estimates are calculated. Finally, examples of a flying control system are used to verify the proposed method. The results show that the proposed method is feasible and effective.

  10. Testability evaluation using prior information of multiple sources

    Directory of Open Access Journals (Sweden)

    Wang Chao

    2014-08-01

    Full Text Available Testability plays an important role in improving the readiness and decreasing the life-cycle cost of equipment. Testability demonstration and evaluation is of significance in measuring such testability indexes as fault detection rate (FDR and fault isolation rate (FIR, which is useful to the producer in mastering the testability level and improving the testability design, and helpful to the consumer in making purchase decisions. Aiming at the problems with a small sample of testability demonstration test data (TDTD such as low evaluation confidence and inaccurate result, a testability evaluation method is proposed based on the prior information of multiple sources and Bayes theory. Firstly, the types of prior information are analyzed. The maximum entropy method is applied to the prior information with the mean and interval estimate forms on the testability index to obtain the parameters of prior probability density function (PDF, and the empirical Bayesian method is used to get the parameters for the prior information with a success-fail form. Then, a parametrical data consistency check method is used to check the compatibility between all the sources of prior information and TDTD. For the prior information to pass the check, the prior credibility is calculated. A mixed prior distribution is formed based on the prior PDFs and the corresponding credibility. The Bayesian posterior distribution model is acquired with the mixed prior distribution and TDTD, based on which the point and interval estimates are calculated. Finally, examples of a flying control system are used to verify the proposed method. The results show that the proposed method is feasible and effective.

  11. Integrating prior knowledge and structure from motion

    DEFF Research Database (Denmark)

    Guilbert, Nicolas; Aanæs, Henrik; Larsen, Rasmus

    2001-01-01

    A new approach for formulating prior knowledge in structure form motion is presented, where the structure is viewed as a 3D stochastic variable, hereby priors are more naturally expressed. It is demonstrated that this formulation is efficient for regularizing structure reconstruction via prior...... knowledge. Specifically algorithms for imposing priors in the proposed formulation are presented....

  12. Acquisition of multiple prior distributions in tactile temporal order judgment

    Directory of Open Access Journals (Sweden)

    Yasuhito eNagai

    2012-08-01

    Full Text Available The Bayesian estimation theory proposes that the brain acquires the prior distribution of a task and integrates it with sensory signals to minimize the effect of sensory noise. Psychophysical studies have demonstrated that our brain actually implements Bayesian estimation in a variety of sensory-motor tasks. However, these studies only imposed one prior distribution on participants within a task period. In this study, we investigated the conditions that enable the acquisition of multiple prior distributions in temporal order judgment (TOJ of two tactile stimuli across the hands. In Experiment 1, stimulation intervals were randomly selected from one of two prior distributions (biased to right hand earlier and biased to left hand earlier in association with color cues (green and red, respectively. Although the acquisition of the two priors was not enabled by the color cues alone, it was significant when participants shifted their gaze (above or below in response to the color cues. However, the acquisition of multiple priors was not significant when participants moved their mouths (opened or closed. In Experiment 2, the spatial cues (above and below were used to identify which eye position or retinal cue position was crucial for the eye-movement-dependent acquisition of multiple priors in Experiment 1. The acquisition of the two priors was significant when participants moved their gaze to the cues (i.e., the cue positions on the retina were constant across the priors, as well as when participants did not shift their gazes (i.e., the cue positions on the retina changed according to the priors. Thus, both eye and retinal cue positions were effective in acquiring multiple priors. Based on previous neurophysiological reports, we discuss possible neural correlates that contribute to the acquisition of multiple priors.

  13. Speciation of Tl(III and Tl(I in hair samples by dispersive liquid–liquid microextraction based on solidification of floating organic droplet prior to flame atomic absorption spectrometry determination

    Directory of Open Access Journals (Sweden)

    S.Z. Mohammadi

    2016-11-01

    Full Text Available Dispersive liquid–liquid microextraction based on solidification of floating organic droplet was successfully used as a sample preparation method prior to flame atomic absorption determination of trace amounts of Tl(III and Tl(I in hair samples. In the proposed method, 1-(2-pyridylazo-2-naphthol, 1-dodecanol and ethanol were used as chelating agent, extraction and dispersive solvent, respectively. Several factors that may be affected in the extraction process, such as type and volume of extraction and disperser solvents, pH, salting out effect, ionic strength and extraction time were studied. Under the optimal conditions, linearity was maintained between 6.0 and 900.0 ng mL−1 for Tl(III. The relative standard deviation for seven replicate determinations of 0.2 μg mL−1 Tl(III was 2.5%. The detection limit based on 3Sb for Tl(III in the original solution was 2.1 ng mL−1. The proposed method has been applied for the determination of trace amounts of thallium in hair samples and satisfactory results were obtained.

  14. How prior expectations shape multisensory perception.

    Science.gov (United States)

    Gau, Remi; Noppeney, Uta

    2016-01-01

    The brain generates a representation of our environment by integrating signals from a common source, but segregating signals from different sources. This fMRI study investigated how the brain arbitrates between perceptual integration and segregation based on top-down congruency expectations and bottom-up stimulus-bound congruency cues. Participants were presented audiovisual movies of phonologically congruent, incongruent or McGurk syllables that can be integrated into an illusory percept (e.g. "ti" percept for visual «ki» with auditory /pi/). They reported the syllable they perceived. Critically, we manipulated participants' top-down congruency expectations by presenting McGurk stimuli embedded in blocks of congruent or incongruent syllables. Behaviorally, participants were more likely to fuse audiovisual signals into an illusory McGurk percept in congruent than incongruent contexts. At the neural level, the left inferior frontal sulcus (lIFS) showed increased activations for bottom-up incongruent relative to congruent inputs. Moreover, lIFS activations were increased for physically identical McGurk stimuli, when participants segregated the audiovisual signals and reported their auditory percept. Critically, this activation increase for perceptual segregation was amplified when participants expected audiovisually incongruent signals based on prior sensory experience. Collectively, our results demonstrate that the lIFS combines top-down prior (in)congruency expectations with bottom-up (in)congruency cues to arbitrate between multisensory integration and segregation.

  15. Depth image enhancement using perceptual texture priors

    Science.gov (United States)

    Bang, Duhyeon; Shim, Hyunjung

    2015-03-01

    A depth camera is widely used in various applications because it provides a depth image of the scene in real time. However, due to the limited power consumption, the depth camera presents severe noises, incapable of providing the high quality 3D data. Although the smoothness prior is often employed to subside the depth noise, it discards the geometric details so to degrade the distance resolution and hinder achieving the realism in 3D contents. In this paper, we propose a perceptual-based depth image enhancement technique that automatically recovers the depth details of various textures, using a statistical framework inspired by human mechanism of perceiving surface details by texture priors. We construct the database composed of the high quality normals. Based on the recent studies in human visual perception (HVP), we select the pattern density as a primary feature to classify textures. Upon the classification results, we match and substitute the noisy input normals with high quality normals in the database. As a result, our method provides the high quality depth image preserving the surface details. We expect that our work is effective to enhance the details of depth image from 3D sensors and to provide a high-fidelity virtual reality experience.

  16. 24 hours prior to curtain.

    Science.gov (United States)

    Mishra, S; Rosen, C A; Murry, T

    2000-03-01

    A retrospective review was conducted of 40 singers presenting with acute voice problems prior to performance. The purpose of this study was to determine the reasons for seeking emergent voice treatment, the types of acute voice disorders, and the performance outcome. The patients were assessed by age, singing style, years of experience, chief complaint, laryngovideostroboscopic findings, and treatment regimens. The outcomes were classified as full, restricted, or no performance. The majority of patients were classical singers. Laryngovideostroboscopy frequently revealed a pattern of early glottic contact at the mid-portion of the membranous vocal fold in patients with acute laryngitis. Experienced singers uniformly sought treatment many days before their performance compared with inexperienced singers who presented closer in time to performance. Six patients initially withheld information, which had a bearing on their acute management. The results of this study suggest that there is a need to accurately diagnose and treat the singer's emergent problem and educate singers regarding early evaluation of medical problems. With modern evaluation techniques and multi-modality treatment, 85% of the singers proceeded to full performance without negative sequelae.

  17. 基于暗原色先验的雾天图像车牌定位%License Plate Location Based on Dark Channel Prior in Fog-degraded Images

    Institute of Scientific and Technical Information of China (English)

    鞠丽丽; 王英

    2016-01-01

    在雾天条件下,会影响到基于传统车牌识别方法的车牌识别系统的车牌识别准确率。首先根据He提出的暗原色先验原理应用IMF算法对图像去雾处理;然后进行小波边缘检测,定位车牌候选区域;最后根据车牌先验知识定位车牌区域。实验表明,该方法对雾天条件下车牌定位有良好的效果。%Fog weather conditions affect the license plate recognition system accuracy,which based on traditional license plate recognition method.Firstly,this paper employs Dark Channel Prior principle proposed by He to eliminate the influence of fog weather.Secondly uses b-spline wavelet edge detection to position license plate candidate area of restored images,final-ly locates the license plate according to the the candidate area.

  18. Mixed hemimicelles solid-phase extraction based on sodium dodecyl sulfate-coated nano-magnets for selective adsorption and enrichment of illegal cationic dyes in food matrices prior to high-performance liquid chromatography-diode array detection detection.

    Science.gov (United States)

    Qi, Ping; Liang, Zhi-an; Wang, Yu; Xiao, Jian; Liu, Jia; Zhou, Qing-qiong; Zheng, Chun-hao; Luo, Li-Ni; Lin, Zi-hao; Zhu, Fang; Zhang, Xue-wu

    2016-03-11

    In this study, mixed hemimicelles solid-phase extraction (MHSPE) based on sodium dodecyl sulfate (SDS) coated nano-magnets Fe3O4 was investigated as a novel method for the extraction and separation of four banned cationic dyes, Auramine O, Rhodamine B, Basic orange 21 and Basic orange 22, in condiments prior to HPLC detection. The main factors affecting the extraction of analysts, such as pH, surfactant and adsorbent concentrations and zeta potential were studied and optimized. Under optimized conditions, the proposed method was successful applied for the analysis of banned cationic dyes in food samples such as chili sauce, soybean paste and tomato sauce. Validation data showed the good recoveries in the range of 70.1-104.5%, with relative standard deviations less than 15%. The method limits of determination/quantification were in the range of 0.2-0.9 and 0.7-3μgkg(-1), respectively. The selective adsorption and enrichment of cationic dyes were achieved by the synergistic effects of hydrophobic interactions and electrostatic attraction between mixed hemimicelles and the cationic dyes, which also resulted in the removal of natural pigments interferences from sample extracts. When applied to real samples, RB was detected in several positive samples (chili powders) within the range from 0.042 to 0.177mgkg(-1). These results indicate that magnetic MHSPE is an efficient and selective sample preparation technique for the extraction of banned cationic dyes in a complex matrix.

  19. Timescales of magmatic processes prior to the ˜4.7 ka Agnano-Monte Spina eruption (Campi Flegrei caldera, Southern Italy) based on diffusion chronometry from sanidine phenocrysts

    Science.gov (United States)

    Iovine, Raffaella Silvia; Fedele, Lorenzo; Mazzeo, Fabio Carmine; Arienzo, Ilenia; Cavallo, Andrea; Wörner, Gerhard; Orsi, Giovanni; Civetta, Lucia; D'Antonio, Massimo

    2017-02-01

    Barium diffusion chronometry applied to sanidine phenocrysts from the trachytic Agnano-Monte Spina eruption (˜4.7 ka) constrains the time between reactivation and eruption of magma batches in the Campi Flegrei caldera. Backscattered electron imaging and quantitative electron microprobe measurements on 50 sanidine phenocrysts from representative pumice samples document core-to-rim compositional zoning. We focus on compositional breaks near the crystal rims that record magma mixing processes just prior to eruption. Diffusion times were modeled at a magmatic temperature of 930 °C using profiles based on quantitative BaO point analyses, X-ray scans, and grayscale swath profiles, yielding times ≤60 years between mixing and eruption. Such short timescales are consistent with volcanological and geochronological data that indicate that at least six eruptions occurred in the Agnano-San Vito area during few centuries before the Agnano-Monte Spina eruption. Thus, the short diffusion timescales are similar to time intervals between eruptions. Therefore, the rejuvenation time of magma residing in a shallow reservoir after influx of a new magma batch that triggered the eruption, and thus pre-eruption warning times, may be as short as years to a few decades at Campi Flegrei caldera.

  20. Systematic review and meta-analysis of L1-VLP-based human papillomavirus vaccine efficacy against anogenital pre-cancer in women with evidence of prior HPV exposure.

    Directory of Open Access Journals (Sweden)

    Ada Miltz

    Full Text Available BACKGROUND: It is unclear whether L1-VLP-based human papillomavirus (HPV vaccines are efficacious in reducing the likelihood of anogenital pre-cancer in women with evidence of prior vaccine-type HPV exposure. This study aims to determine whether the combined results of the vaccine trials published to date provide evidence of efficacy compared with control (hepatitis A vaccine/placebo. METHODS: A systematic review and meta-analysis was conducted. Randomized-controlled trials (RCTs were identified from MEDLINE, Embase, Web of Science, PubMed, Cochrane Central Register of Controlled Trials and references of identified studies. The bivalent vaccine containing HPV-16 and 18 VLPs from GlaxoSmithKline Biologicals (Rixenstart, Belgium, the quadrivalent vaccine containing HPV-6, 11, 16, and 18 VLPs from Merck & Co., Inc., (Whitehouse Station, NJ USA, and the HPV-16 monovalent vaccine from Merck Research Laboratories (West Point, PA USA were evaluated. FINDINGS: Three RCT reports and two post-trial cohort studies were eligible, comprising data from 13,482 women who were included in the vaccine studies but had evidence of HPV infection at study entry. Data on efficacy was synthesized using the Mantel-Haenszel weighted fixed-effect approach, or where there was heterogeneity between studies, the DerSimonian and Laird weighted random-effect approach. The mean odds ratio (OR and 95% confidence interval (CI for the association between Cervarix, Gardasil and HPV-16 monovalent vaccine and HPV-associated cervical intraepithelial neoplasia grade 3 or worse was 0·90 (95% CI: 0·56, 1·44. For the association between Gardasil and HPV-associated vulval/vaginal intraepithelial neoplasia grades 2-3, the overall OR and 95% CI was 2.25 (95% CI: 0·78, 6.50. Sample size and follow-up were limited. CONCLUSIONS: There was no evidence that HPV vaccines are effective in preventing vaccine-type HPV associated pre-cancer in women with evidence of prior HPV exposure. Small

  1. 34 CFR 642.32 - Prior experience.

    Science.gov (United States)

    2010-07-01

    ... 34 Education 3 2010-07-01 2010-07-01 false Prior experience. 642.32 Section 642.32 Education....32 Prior experience. (a)(1) The Secretary gives priority to each applicant that has conducted a... points to be awarded each eligible applicant, the Secretary considers the applicant's prior experience of...

  2. Iterated random walks with shape prior

    DEFF Research Database (Denmark)

    Pujadas, Esmeralda Ruiz; Kjer, Hans Martin; Piella, Gemma;

    2016-01-01

    We propose a new framework for image segmentation using random walks where a distance shape prior is combined with a region term. The shape prior is weighted by a confidence map to reduce the influence of the prior in high gradient areas and the region term is computed with k-means to estimate th...

  3. Bayesian Inference for Structured Spike and Slab Priors

    DEFF Research Database (Denmark)

    Andersen, Michael Riis; Winther, Ole; Hansen, Lars Kai

    2014-01-01

    Sparse signal recovery addresses the problem of solving underdetermined linear inverse problems subject to a sparsity constraint. We propose a novel prior formulation, the structured spike and slab prior, which allows to incorporate a priori knowledge of the sparsity pattern by imposing a spatial...... Gaussian process on the spike and slab probabilities. Thus, prior information on the structure of the sparsity pattern can be encoded using generic covariance functions. Furthermore, we provide a Bayesian inference scheme for the proposed model based on the expectation propagation framework. Using...

  4. Bayesian Inference for Structured Spike and Slab Priors

    DEFF Research Database (Denmark)

    Andersen, Michael Riis; Winther, Ole; Hansen, Lars Kai

    2014-01-01

    Sparse signal recovery addresses the problem of solving underdetermined linear inverse problems subject to a sparsity constraint. We propose a novel prior formulation, the structured spike and slab prior, which allows to incorporate a priori knowledge of the sparsity pattern by imposing a spatial...... Gaussian process on the spike and slab probabilities. Thus, prior information on the structure of the sparsity pattern can be encoded using generic covariance functions. Furthermore, we provide a Bayesian inference scheme for the proposed model based on the expectation propagation framework. Using...

  5. Variational segmentation problems using prior knowledge in imaging and vision

    DEFF Research Database (Denmark)

    Fundana, Ketut

    This dissertation addresses variational formulation of segmentation problems using prior knowledge. Variational models are among the most successful approaches for solving many Computer Vision and Image Processing problems. The models aim at finding the solution to a given energy functional defined......, prior knowledge is needed to obtain the desired solution. The introduction of shape priors in particular, has proven to be an effective way to segment objects of interests. Firstly, we propose a prior-based variational segmentation model to segment objects of interest in image sequences, that can deal...... pose invariant parameters complicate the optimization of the model. To overcome the common numerical problems associated with the step size of the pose parameters in the discretization of the pose model, we propose a novel gradient procedure for the pose estimation based on the construction...

  6. The power prior: theory and applications.

    Science.gov (United States)

    Ibrahim, Joseph G; Chen, Ming-Hui; Gwon, Yeongjin; Chen, Fang

    2015-12-10

    The power prior has been widely used in many applications covering a large number of disciplines. The power prior is intended to be an informative prior constructed from historical data. It has been used in clinical trials, genetics, health care, psychology, environmental health, engineering, economics, and business. It has also been applied for a wide variety of models and settings, both in the experimental design and analysis contexts. In this review article, we give an A-to-Z exposition of the power prior and its applications to date. We review its theoretical properties, variations in its formulation, statistical contexts for which it has been used, applications, and its advantages over other informative priors. We review models for which it has been used, including generalized linear models, survival models, and random effects models. Statistical areas where the power prior has been used include model selection, experimental design, hierarchical modeling, and conjugate priors. Frequentist properties of power priors in posterior inference are established, and a simulation study is conducted to further examine the empirical performance of the posterior estimates with power priors. Real data analyses are given illustrating the power prior as well as the use of the power prior in the Bayesian design of clinical trials.

  7. Hydroxy-thioxanthones as suitable neutral ionophores for the preparation of PVC-membrane potentiometric sensors for Al(III) ion.

    Science.gov (United States)

    Shamsipur, Mojtaba; Ershad, Sohrab; Yari, Absollah; Sharghi, Hashem; Salimi, Ali Reza

    2004-02-01

    The complexation of five recently synthesized hydroxy-thioxanthone derivatives with Al3+ ion was studied in a methanol solution spectrophotometrically, and the stepwise formation constants of the resulting 1:1 and 2:1 (ligand-to-metal) complexes were evaluated. The suitability of the thioxanthone derivatives as neutral ionophores for the preparation of a new Al3+ ion-selective PVC-membrane electrode was investigated, and 1-hydroxy-3-methyl-thiocanthone was selected as the best compound for this purpose. The prepared electrode exhibits a Nernstian response for Al3+ ions over a wide concentration range (2.0 x 10(-2) to 2.0 x 10(-6) M), with a limit of detection of 1.0 x 10(-6) M. It has a very fast response time of about 5 s and can be used for at least 3 months without any considerable divergence in the potentials. The proposed membrane sensor revealed very good selectivities for Al3+ over a wide variety of other metal ions, and could be used at a working pH range of 3.4 - 5.0. It was used as an indicator electrode in potentiometric titration of aluminum ions with EDTA, and in the determination of Al3+ in different real samples.

  8. Immunodeficiency after allogeneic bone marrow transplantation in man. Effect of phorbol ester (phorbol myristate acetate) and calcium ionophore (A23187) in vitro

    DEFF Research Database (Denmark)

    Møller, J; Hofmann, B; Langhoff, E

    1989-01-01

    This study was undertaken to clarify the mechanism behind the severely decreased lymphocyte proliferative response upon stimulation with mitogens and antigens seen after allogeneic bone marrow transplantation (BMT) in man. We investigated eight BMT patients and eight controls and found that the p......This study was undertaken to clarify the mechanism behind the severely decreased lymphocyte proliferative response upon stimulation with mitogens and antigens seen after allogeneic bone marrow transplantation (BMT) in man. We investigated eight BMT patients and eight controls and found...... that the proliferative response of patient cells was reduced both when the cells were stimulated with phytohaemagglutinin (PHA) and when they were stimulated with a combination of phorbol myristate acetate (PMA), which is an activator of protein kinase C (PKC), and the calcium ionophore A23187, which irreversibly opens......) receptors (CD25) was only slightly decreased. However, the production of IL-2 was severely decreased in patient cells after stimulation with A23187/PMA (median 3541 units), although it was higher than in PHA-stimulated control cells (median 354 units). These results show that a direct activation of PKC...

  9. Intermediates in monensin biosynthesis: A late step in biosynthesis of the polyether ionophore monensin is crucial for the integrity of cation binding

    Directory of Open Access Journals (Sweden)

    Wolfgang Hüttel

    2014-02-01

    Full Text Available Polyether antibiotics such as monensin are biosynthesised via a cascade of directed ring expansions operating on a putative polyepoxide precursor. The resulting structures containing fused cyclic ethers and a lipophilic backbone can form strong ionophoric complexes with certain metal cations. In this work, we demonstrate for monensin biosynthesis that, as well as ether formation, a late-stage hydroxylation step is crucial for the correct formation of the sodium monensin complex. We have investigated the last two steps in monensin biosynthesis, namely hydroxylation catalysed by the P450 monooxygenase MonD and O-methylation catalysed by the methyl-transferase MonE. The corresponding genes were deleted in-frame in a monensin-overproducing strain of Streptomyces cinnamonensis. The mutants produced the expected monensin derivatives in excellent yields (ΔmonD: 1.13 g L−1 dehydroxymonensin; ΔmonE: 0.50 g L−1 demethylmonensin; and double mutant ΔmonDΔmonE: 0.34 g L−1 dehydroxydemethylmonensin. Single crystals were obtained from purified fractions of dehydroxymonensin and demethylmonensin. X-ray structure analysis revealed that the conformation of sodium dimethylmonensin is very similar to that of sodium monensin. In contrast, the coordination of the sodium ion is significantly different in the sodium dehydroxymonensin complex. This shows that the final constitution of the sodium monensin complex requires this tailoring step as well as polyether formation.

  10. Intermediates in monensin biosynthesis: A late step in biosynthesis of the polyether ionophore monensin is crucial for the integrity of cation binding

    Science.gov (United States)

    Spencer, Jonathan B; Leadlay, Peter F

    2014-01-01

    Summary Polyether antibiotics such as monensin are biosynthesised via a cascade of directed ring expansions operating on a putative polyepoxide precursor. The resulting structures containing fused cyclic ethers and a lipophilic backbone can form strong ionophoric complexes with certain metal cations. In this work, we demonstrate for monensin biosynthesis that, as well as ether formation, a late-stage hydroxylation step is crucial for the correct formation of the sodium monensin complex. We have investigated the last two steps in monensin biosynthesis, namely hydroxylation catalysed by the P450 monooxygenase MonD and O-methylation catalysed by the methyl-transferase MonE. The corresponding genes were deleted in-frame in a monensin-overproducing strain of Streptomyces cinnamonensis. The mutants produced the expected monensin derivatives in excellent yields (ΔmonD: 1.13 g L−1 dehydroxymonensin; ΔmonE: 0.50 g L−1 demethylmonensin; and double mutant ΔmonDΔmonE: 0.34 g L−1 dehydroxydemethylmonensin). Single crystals were obtained from purified fractions of dehydroxymonensin and demethylmonensin. X-ray structure analysis revealed that the conformation of sodium dimethylmonensin is very similar to that of sodium monensin. In contrast, the coordination of the sodium ion is significantly different in the sodium dehydroxymonensin complex. This shows that the final constitution of the sodium monensin complex requires this tailoring step as well as polyether formation. PMID:24605157

  11. PROBABILISTIC SHEAR STRENGTH MODEL FOR DEEP FLEXURAL MEMBERS BASED ON CONJUGATE PRIOR DISTRIBUTION%基于共轭先验分布的深受弯构件受剪承载力概率模型分析

    Institute of Scientific and Technical Information of China (English)

    刘伯权; 刘喜; 吴涛

    2015-01-01

    Some models have been presented by domestic and foreign scholars for shear capacity of deep reinforced concrete flexural members,but there is still no generally accepted shear theory model.Bayesian theory has been applied to predict and design the bearing capacity for some reinforced concrete members,the reasonability,accuracy and superiority of which have been demonstrated,too.However,the calculation results and accuracy are different for different prior distributions.This paper develops probabilistic shear strength models for reinforced concrete deep flexural members by using of Bayesian multivariate statistical theory based on conjugate prior distribution.These probabilistic models are simplified through the Bayesian parameters removal process.Their performance is confirmed by comparison with 115 collected test results.This shows that the deep flexural members' shear strengths,as obtained by the simplified model based on Bayesian theory,are in good agreement with test results,and they are closer to the experimental values than the results given by models used in many nations' codes.The simplified models can be used in shear strength prediction and design for deep flexural members.%钢筋混凝土深受弯构件由于影响因素多、受力复杂,其计算模型和设计方法未形成统一定论.贝叶斯理论己被应用于钢筋混凝土部分构件承载力的预测和设计中,且合理性、准确性及优越性己得到证明,然其先验分布的选取不同,对计算结果的精度影响不同.采用共轭分布法推导了贝叶斯参数先验分布,利用贝叶斯多元统计理论,建立了基于共轭分布的钢筋混凝土深受弯构件受剪承载力贝叶斯概率模型,通过贝叶斯后验参数剔除法简化概率模型,并结合国内外学者己完成115组钢筋混凝土深受弯构件受剪性能试验结果验证模型.研究表明:基于贝叶斯简化模型得到的深受弯构件受剪承载力与试验结果吻合良好,较各

  12. Fast image haze-removal algorithm based on the prior dark-channel%基于暗原色先验模型的快速去雾算法

    Institute of Scientific and Technical Information of China (English)

    张冰冰; 戴声奎; 孙万源

    2013-01-01

    In order to eliminate fog or haze in outdoor images in real time, a fast haze-removal algorithm is proposed based on the theory of dark channel prior. By improving the transmission repairing method, the computational effort is reduced. Furthermore, by self-adaptively controlling the values of transmission-rate lower limits and the global atmospheric lights, this algorithm could be used in more image dehazing applications. Finally, a post-processing procedure is adopted to enhance the visual effect of the dehazed image. Experiments show that the presented method processes the fog image effectively and fast, making the algorithm easy to achieve real-time capabilities.%为了实时地消除图像中的雾气,提出了一种基于暗原色先验理论的快速去雾算法.改进了透射率修复方法,显著地减少了算法的计算量;通过自适应调节透射率下限值和大气光成分值,扩大了去雾处理的适用范围;对复原的图像进行增强处理,改善了复原图像的整体视觉效果.实验结果表明,本文算法能有效地去除图像中的雾气,同时提高了算法的处理速度,有利于算法的实时实现.

  13. The IVF Outcome Counseling Based on the Model Combining DHEAS and Age in Patients with Low AMH Prior to the First Cycle of GnRH Antagonist Protocol of Ovarian Stimulation

    Directory of Open Access Journals (Sweden)

    Miro Šimun Alebić

    2013-01-01

    Full Text Available Objective. To investigate the endocrine and/or clinical characteristics of women with low anti-Müllerian hormone (AMH that could improve the accuracy of IVF outcome prediction based on the female age alone prior to the first GnRH antagonist IVF cycle. Methods. Medical records of 129 patients with low AMH level (<6.5 pmol/L who underwent their first GnRH antagonist ovarian stimulation protocol for IVF/ICSI were retrospectively analyzed. The main outcome measure was the area under the ROC curve (AUC-ROC for the models combining age and other potential predictive factors for the clinical pregnancy. Results. Clinical pregnancy rate (CPR per initiated cycles was 11.6%. For the prediction of clinical pregnancy, DHEAS and age showed AUC-ROC of 0.726 (95%CI 0.641–0.801 and 0.662 (95%CI 0.573–0.743, respectively (. The predictive accuracy of the model combining age and DHEAS (AUC-ROC 0.796; 95%CI 0.716–0.862 was significantly higher compared to that of age alone (. In patients <37.5 years with DHEAS  pmol/L, 60% (9/15 of all pregnancies were achieved with CPR of 37.5%. Conclusions. DHEAS appears to be predictive for clinical pregnancy in younger women (<37.5 years with low AMH after the first GnRH antagonist IVF cycle. Therefore, DHEAS-age model could refine the pretreatment counseling on pregnancy prospects following IVF.

  14. Improving semantic scene understanding using prior information

    Science.gov (United States)

    Laddha, Ankit; Hebert, Martial

    2016-05-01

    Perception for ground robot mobility requires automatic generation of descriptions of the robot's surroundings from sensor input (cameras, LADARs, etc.). Effective techniques for scene understanding have been developed, but they are generally purely bottom-up in that they rely entirely on classifying features from the input data based on learned models. In fact, perception systems for ground robots have a lot of information at their disposal from knowledge about the domain and the task. For example, a robot in urban environments might have access to approximate maps that can guide the scene interpretation process. In this paper, we explore practical ways to combine such prior information with state of the art scene understanding approaches.

  15. Theoretical Priors On Modified Growth Parametrisations

    CERN Document Server

    Song, Yong-Seon; Caldera-Cabral, Gabriela; Koyama, Kazuya

    2010-01-01

    Next generation surveys will observe the large-scale structure of the Universe with unprecedented accuracy. This will enable us to test the relationships between matter over-densities, the curvature perturbation and the Newtonian potential. Any large-distance modification of gravity or exotic nature of dark energy modifies these relationships as compared to those predicted in the standard smooth dark energy model based on General Relativity. In linear theory of structure growth such modifications are often parameterised by virtue of two functions of space and time that enter the relation of the curvature perturbation to, first, the matter over-density, and second, the Newtonian potential. We investigate the predictions for these functions in Brans-Dicke theory, clustering dark energy models and interacting dark energy models. We find that each theory has a distinct path in the parameter space of modified growth. Understanding these theoretical priors on the parameterisations of modified growth is essential to...

  16. Sparse Multivariate Modeling: Priors and Applications

    DEFF Research Database (Denmark)

    Henao, Ricardo

    modeling, a model for peptide-protein/protein-protein interactions called latent protein tree, a framework for sparse Gaussian process classification based on active set selection and a linear multi-category sparse classifier specially targeted to gene expression data. The thesis is organized to provide......This thesis presents a collection of statistical models that attempt to take advantage of every piece of prior knowledge available to provide the models with as much structure as possible. The main motivation for introducing these models is interpretability since in practice we want to be able...... to use them as hypothesis generating tools. All of our models start from a family of structures, for instance factor models, directed acyclic graphs, classifiers, etc. Then we let them be selectively sparse as a way to provide them with structural fl exibility and interpretability. Finally, we complement...

  17. Implicit Priors in Galaxy Cluster Mass and Scaling Relation Determinations

    Science.gov (United States)

    Mantz, A.; Allen, S. W.

    2011-01-01

    Deriving the total masses of galaxy clusters from observations of the intracluster medium (ICM) generally requires some prior information, in addition to the assumptions of hydrostatic equilibrium and spherical symmetry. Often, this information takes the form of particular parametrized functions used to describe the cluster gas density and temperature profiles. In this paper, we investigate the implicit priors on hydrostatic masses that result from this fully parametric approach, and the implications of such priors for scaling relations formed from those masses. We show that the application of such fully parametric models of the ICM naturally imposes a prior on the slopes of the derived scaling relations, favoring the self-similar model, and argue that this prior may be influential in practice. In contrast, this bias does not exist for techniques which adopt an explicit prior on the form of the mass profile but describe the ICM non-parametrically. Constraints on the slope of the cluster mass-temperature relation in the literature show a separation based the approach employed, with the results from fully parametric ICM modeling clustering nearer the self-similar value. Given that a primary goal of scaling relation analyses is to test the self-similar model, the application of methods subject to strong, implicit priors should be avoided. Alternative methods and best practices are discussed.

  18. Novice and expert teachers' conceptions of learners' prior knowledge

    Science.gov (United States)

    Meyer, Helen

    2004-11-01

    This study presents comparative case studies of preservice and first-year teachers' and expert teachers' conceptions of the concept of prior knowledge. Kelly's (The Psychology of Personal Construct, New York: W.W. Norton, 1955) theory of personal constructs as discussed by Akerson, Flick, and Lederman (Journal of Research in Science Teaching, 2000, 37, 363-385) in relationship to prior knowledge underpins the study. Six teachers were selected to participate in the case studies based upon their level experience teaching science and their willingness to take part. The comparative case studies of the novice and expert teachers provide insights into (a) how novice and expert teachers understand the concept of prior knowledge and (b) how they use this knowledge to make instructional decisions. Data collection consisted of interviews, classroom observations, and document analysis. Findings suggest that novice teachers hold insufficient conceptions of prior knowledge and its role in instruction to effectively implement constructivist teaching practices. While expert teachers hold a complex conception of prior knowledge and make use of their students' prior knowledge in significant ways during instruction. A second finding was an apparent mismatch between the novice teachers' beliefs about their urban students' life experiences and prior knowledge and the wealth of knowledge the expert teachers found to draw upon.

  19. Data on NAEP 2011 writing assessment prior computer use.

    Science.gov (United States)

    Tate, Tamara P; Warschauer, Mark; Abedi, Jamal

    2016-09-01

    This data article contains information based on the 2011 National Assessment of Educational Progress in Writing Restricted-Use Data, available from the National Center for Education Statistics (NCES Pub. No. 2014476). https://nces.ed.gov/nationsreportcard/researchcenter/datatools.aspx. The data include the statistical relationships between survey reports of teachers and students regarding prior use of computers and other technology and writing achievement levels on the 2011 computer-based NAEP writing assessment. This data article accompanies "The Effects of Prior Computer Use on Computer-Based Writing: The 2011 NAEP Writing Assessment" [1].

  20. Data on NAEP 2011 writing assessment prior computer use

    Directory of Open Access Journals (Sweden)

    Tamara P. Tate

    2016-09-01

    Full Text Available This data article contains information based on the 2011 National Assessment of Educational Progress in Writing Restricted-Use Data, available from the National Center for Education Statistics (NCES Pub. No. 2014476. https://nces.ed.gov/nationsreportcard/researchcenter/datatools.aspx. The data include the statistical relationships between survey reports of teachers and students regarding prior use of computers and other technology and writing achievement levels on the 2011 computer-based NAEP writing assessment. This data article accompanies “The Effects of Prior Computer Use on Computer-Based Writing: The 2011 NAEP Writing Assessment” [1].

  1. Assessment of prior learning in vocational education and training

    DEFF Research Database (Denmark)

    Wahlgren, Bjarne; Aarkrog, Vibe

    The article deals about the results of a study of the assessment of prior learning among adult workers who want to obtain formal qualifications as skilled workers. The study contributes to developing methods for assessing prior learning including both the teachers’ ways of eliciting the students......’ knowledge, skills and competences during the students’ performances and the methods that the teachers apply in order to assess the students’ prior learning in relation to the regulations of the current VET-program. In particular the study focuses on how to assess not only the students’ explicated knowledge...... and skills but also their competences, i.e. the way the students use their skills and knowledge to perform in practice. Based on a description of the assessment procedures the article discusses central issues in relation to the assessment of prior learning. The empirical data have been obtained in the VET...

  2. Functional uniform priors for nonlinear modeling.

    Science.gov (United States)

    Bornkamp, Björn

    2012-09-01

    This article considers the topic of finding prior distributions when a major component of the statistical model depends on a nonlinear function. Using results on how to construct uniform distributions in general metric spaces, we propose a prior distribution that is uniform in the space of functional shapes of the underlying nonlinear function and then back-transform to obtain a prior distribution for the original model parameters. The primary application considered in this article is nonlinear regression, but the idea might be of interest beyond this case. For nonlinear regression the so constructed priors have the advantage that they are parametrization invariant and do not violate the likelihood principle, as opposed to uniform distributions on the parameters or the Jeffrey's prior, respectively. The utility of the proposed priors is demonstrated in the context of design and analysis of nonlinear regression modeling in clinical dose-finding trials, through a real data example and simulation.

  3. Early Results in Capella's Prior Learning Assessment Experimental Site Initiative

    Science.gov (United States)

    Klein, Jillian

    2017-01-01

    In July 2014, the U.S. Department of Education announced a new round of experimental sites focusing on competency-based education. Capella University was selected to participate in three of the Department of Education's competency-based education (CBE) experiments and began by implementing the prior learning assessment experiment, which allows…

  4. Prior Experiences Shaping Family Science Conversations at a Nature Center

    Science.gov (United States)

    McClain, Lucy R.; Zimmerman, Heather Toomey

    2014-01-01

    Using families as the analytical focus, this study informs the field of informal science education with a focus on the role of prior experiences in family science conversations during nature walks at an outdoor-based nature center. Through video-based research, the team analyzed 16 families during walks at a nature center. Each family's prior…

  5. Assessment of Prior Learning in Adult Vocational Education and Training

    Directory of Open Access Journals (Sweden)

    Vibe Aarkrog

    2015-04-01

    Full Text Available The article deals about the results of a study of school-based Assessment of Prior Learning of adults who have enrolled as students in a VET college in order to qualify for occupations as skilled workers. Based on examples of VET teachers’ methods for assessing the students’ prior learning in the programs for gastronomes, respectively child care assistants the article discusses two issues in relation to Assessment of Prior Learing: the encounter of practical experience and school-based knowledge and the validity and reliability of the assessment procedures. Through focusing on the students’ knowing that and knowing why the assessment is based on a scholastic perception of the students’ needs for training, reflecting one of the most important challenges in Assessment of Prior Learning: how can practical experience be transformed into credits for the knowledge parts of the programs? The study shows that by combining several Assessment of Prior Learning methods and comparing the teachers’ assessments the teachers respond to the issues of validity and reliability. However, validity and reliability might be even further strengthened, if the competencies are well defined, if the education system is aware of securing a reasonable balance between knowing how, knowing that, and knowing why, and if the teachers are adequately trained for the assessment procedures.

  6. Challenges in relation to assessment of prior learning

    DEFF Research Database (Denmark)

    Wahlgren, Bjarne; Aarkrog, Vibe

    2013-01-01

    unskilled workers’) prior learning, i.e. their work experiences and informal learning. In the paper we will describe and point to some challenges in relation to assessing the students’ prior learning. The assessment is accomplished by teachers and supervisors in VET colleges. The assessment includes 1......The paper deals about preliminary results from an on-going project: “From unskilled worker to skilled worker in record time”. The aim of the project is to qualify unskilled workers for skilled positions in record time by drafting up a plan for the training based on assessment of the students’ (the....... Observations and or with the students about the students’ workplace based experiences and learning and 2. Drafting up an individual study plan based on the individual student’s prior learning....

  7. PET Image Reconstruction Using Information Theoretic Anatomical Priors

    Science.gov (United States)

    Somayajula, Sangeetha; Panagiotou, Christos; Rangarajan, Anand; Li, Quanzheng; Arridge, Simon R.

    2011-01-01

    We describe a nonparametric framework for incorporating information from co-registered anatomical images into positron emission tomographic (PET) image reconstruction through priors based on information theoretic similarity measures. We compare and evaluate the use of mutual information (MI) and joint entropy (JE) between feature vectors extracted from the anatomical and PET images as priors in PET reconstruction. Scale-space theory provides a framework for the analysis of images at different levels of detail, and we use this approach to define feature vectors that emphasize prominent boundaries in the anatomical and functional images, and attach less importance to detail and noise that is less likely to be correlated in the two images. Through simulations that model the best case scenario of perfect agreement between the anatomical and functional images, and a more realistic situation with a real magnetic resonance image and a PET phantom that has partial volumes and a smooth variation of intensities, we evaluate the performance of MI and JE based priors in comparison to a Gaussian quadratic prior, which does not use any anatomical information. We also apply this method to clinical brain scan data using F18 Fallypride, a tracer that binds to dopamine receptors and therefore localizes mainly in the striatum. We present an efficient method of computing these priors and their derivatives based on fast Fourier transforms that reduce the complexity of their convolution-like expressions. Our results indicate that while sensitive to initialization and choice of hyperparameters, information theoretic priors can reconstruct images with higher contrast and superior quantitation than quadratic priors. PMID:20851790

  8. Zn(2+ inhibits coronavirus and arterivirus RNA polymerase activity in vitro and zinc ionophores block the replication of these viruses in cell culture.

    Directory of Open Access Journals (Sweden)

    Aartjan J W te Velthuis

    Full Text Available Increasing the intracellular Zn(2+ concentration with zinc-ionophores like pyrithione (PT can efficiently impair the replication of a variety of RNA viruses, including poliovirus and influenza virus. For some viruses this effect has been attributed to interference with viral polyprotein processing. In this study we demonstrate that the combination of Zn(2+ and PT at low concentrations (2 µM Zn(2+ and 2 µM PT inhibits the replication of SARS-coronavirus (SARS-CoV and equine arteritis virus (EAV in cell culture. The RNA synthesis of these two distantly related nidoviruses is catalyzed by an RNA-dependent RNA polymerase (RdRp, which is the core enzyme of their multiprotein replication and transcription complex (RTC. Using an activity assay for RTCs isolated from cells infected with SARS-CoV or EAV--thus eliminating the need for PT to transport Zn(2+ across the plasma membrane--we show that Zn(2+ efficiently inhibits the RNA-synthesizing activity of the RTCs of both viruses. Enzymatic studies using recombinant RdRps (SARS-CoV nsp12 and EAV nsp9 purified from E. coli subsequently revealed that Zn(2+ directly inhibited the in vitro activity of both nidovirus polymerases. More specifically, Zn(2+ was found to block the initiation step of EAV RNA synthesis, whereas in the case of the SARS-CoV RdRp elongation was inhibited and template binding reduced. By chelating Zn(2+ with MgEDTA, the inhibitory effect of the divalent cation could be reversed, which provides a novel experimental tool for in vitro studies of the molecular details of nidovirus replication and transcription.

  9. Effects of an Ionophore Coccidiostat (Monensin or Salinomycin, Sodium or Potassium Bicarbonate, or Both, and Bacitracin Methylene Disalicylate in Broiler Chicken Diets

    Directory of Open Access Journals (Sweden)

    Hooge DM

    2000-01-01

    Full Text Available Peterson x Arbor Acres chicks were grown on used litter to 45 or 46 days of age in three pen trials. Coccidial inoculations were given by water at 14 days of age. Sodium bicarbonate (SBC; 0.20% or potassium bicarbonate (PBC; 0.14% was added to broiler chicken diets containing monensin (MON; 110 mg/kg or salinomycin (SAL; 66 mg/kg in Experiment 1. In Experiment 2, using SAL (55 mg/kg, three dietary bicarbonate treatments (SBC, 0.20%; PBC, 0.20%; or SBC + PBC 0.10% each were tested with or without BMD R (55 mg/kg. Diets differing in SAL, BMD R, and SBC levels were evaluated in Experiment 3. Beneficial interaction was found between ionophores and bicarbonates for mortality (lower when SBC or PBC and MON in Experiment 1. For main effects, in Experiment 1 PBC with MON or SAL improved body weight, feed conversion ratio and mortality. SAL improved weight, feed conversion ratio and mortality compared to MON. In Experiment 2, PBC with SAL improved weight, coccidial lesion score, feed conversion ratio and mortality across two levels of BMD R. The PBC and SBC were equally effective in Experiment 1, but PBC was about 0 to 40% as effective as SBC, depending on parameter in Experiment 2. Half levels of SBC plus PBC generally gave intermediate results between control and SBC. SBC with MON or SAL lowered mortalities, coccidial lesion scores, and feed conversion ratios (Experiments 1 and 2, and increased body weight (Experiment 2. In Experiment 3, BMD R in all feeds improved body weight and feed conversion versus in starter feed only, and SBC with SAL and BMD R improved all performance parameters.

  10. Cathodic ARC surface cleaning prior to brazing

    Energy Technology Data Exchange (ETDEWEB)

    Dave, V. R. (Vivek R.); Hollis, K. J. (Kendall J.); Castro, R. G. (Richard G.); Smith, F. M. (Frank M.); Javernick, D. A. (Daniel A.)

    2002-01-01

    Surface cleanliness is one the critical process variables in vacuum furnace brazing operations. For a large number of metallic components, cleaning is usually accomplished either by water-based alkali cleaning, but may also involve acid etching or solvent cleaning / rinsing. Nickel plating may also be necessary to ensure proper wetting. All of these cleaning or plating technologies have associated waste disposal issues, and this article explores an alternative cleaning process that generates minimal waste. Cathodic arc, or reserve polarity, is well known for welding of materials with tenacious oxide layers such as aluminum alloys. In this work the reverse polarity effect is used to clean austenitic stainless steel substrates prior to brazing with Ag-28%Cu. This cleaning process is compared to acid pickling and is shown to produce similar wetting behavior as measured by dynamic contact angle experiments. Additionally, dynamic contact angle measurements with water drops are conducted to show that cathodic arc cleaning can remove organic contaminants as well. The process does have its limitations however, and alloys with high titanium and aluminum content such as nickel-based superalloys may still require plating to ensure adequate wetting.

  11. High-resolution DOA estimation with Meridian prior

    Science.gov (United States)

    Zhao, Guanghui; Lin, Jie; Shen, Fangfang; Shi, Guangming; Hou, Qingyu; Liu, Zicheng

    2013-12-01

    Based on the assumption that only a few point sources exist in the spatial spectrum, the direction-of-arrival (DOA) estimation problem can be formulated as a problem of sparse representation of signal with respect to a dictionary. By choosing a proper dictionary, the array measurements can be well approximated by a linear combination of a few entries of the dictionary, in which the non-zero elements of the sparse coefficient vector correspond to the targets' arrival direction. Conventionally, the desired sparsity of signal is guaranteed by imposing a constraint of Laplace prior on the distribution of signal. However, its performance is not satisfied under the condition of insufficient data or noisy environment since a lot of false targets will appear. Considering that the Meridian distribution has the characteristic of high energy concentration, we propose to adopt the Meridian prior as the prior distribution of the coefficient vector. Further, we present a new minimization problem with the Meridian prior assumption (MMP) for DOA estimation. Because the Meridian prior imposes a more stringent constraint on the energy localization than the Laplace prior, the proposed MMP method can achieve a better DOA estimation, which is embodied in higher resolution and less false targets. The experiments of both simulation and ground truth data process exhibit the superior performance of our proposed algorithm.

  12. Relationship between Prior Knowledge and Reading Comprehension

    Science.gov (United States)

    Abdelaal, Noureldin Mohamed; Sase, Amal Saleh

    2014-01-01

    This study investigates the relationship between prior knowledge and reading comprehension in second language among postgraduate students in UPM. Participants in the study were 20 students who have the same level in English as a second language from several faculties. On the basis of a prior-knowledge questionnaire and test, students were…

  13. Quantitative Evidence Synthesis with Power Priors

    NARCIS (Netherlands)

    Rietbergen, C.|info:eu-repo/dai/nl/322847796

    2016-01-01

    The aim of this thesis is to provide the applied researcher with a practical approach for quantitative evidence synthesis using the conditional power prior that allows for subjective input and thereby provides an alternative tgbgo deal with the difficulties as- sociated with the joint power prior

  14. Quantitative Evidence Synthesis with Power Priors

    NARCIS (Netherlands)

    Rietbergen, C.

    2016-01-01

    The aim of this thesis is to provide the applied researcher with a practical approach for quantitative evidence synthesis using the conditional power prior that allows for subjective input and thereby provides an alternative tgbgo deal with the difficulties as- sociated with the joint power prior di

  15. Signaling Without Common Prior : An Experiment

    NARCIS (Netherlands)

    Drouvelis, M.; Müller, W.; Possajennikov, A.

    2009-01-01

    The common prior assumption is pervasive in game-theoretic models with incomplete information. This paper investigates experimentally the importance of inducing a common prior in a two-person signaling game. For a specific probability distribution of the sender’s type, the long-run behavior without

  16. Signaling Without Common Prior : An Experiment

    NARCIS (Netherlands)

    Drouvelis, M.; Müller, W.; Possajennikov, A.

    2009-01-01

    The common prior assumption is pervasive in game-theoretic models with incomplete information. This paper investigates experimentally the importance of inducing a common prior in a two-person signaling game. For a specific probability distribution of the sender’s type, the long-run behavior without

  17. Improving Open Access through Prior Learning Assessment

    Science.gov (United States)

    Yin, Shuangxu; Kawachi, Paul

    2013-01-01

    This paper explores and presents new data on how to improve open access in distance education through using prior learning assessments. Broadly there are three types of prior learning assessment (PLAR): Type-1 for prospective students to be allowed to register for a course; Type-2 for current students to avoid duplicating work-load to gain…

  18. Priors, Posterior Odds and Lagrange Multiplier Statistics in Bayesian Analyses of Cointegration

    NARCIS (Netherlands)

    F.R. Kleibergen (Frank); R. Paap (Richard)

    1996-01-01

    textabstractUsing the standard linear model as a base, a unified theory of Bayesian Analyses of Cointegration Models is constructed. This is achieved by defining (natural conjugate) priors in the linear model and using the implied priors for the cointegration model. Using these priors, posterior res

  19. Vibrational excitons in ionophores: Experimental probes for quantum coherence-assisted ion transport and selectivity in ion channels

    CERN Document Server

    Ganim, Ziad; Vaziri, Alipasha

    2011-01-01

    Despite a large body of work, the exact molecular details underlying ion-selectivity and transport in the potassium channel have not been fully laid to rest. One major reason has been the lack of experimental methods that can probe these mechanisms dynamically on their biologically relevant time scales. Recently it was suggested that quantum coherence and its interplay with thermal vibration might be involved in mediating ion-selectivity and transport. In this work we present an experimental strategy for using time resolved infrared spectroscopy to investigate these effects. We show the feasibility by demonstrating the IR absorption and Raman spectroscopic signatures of potassium binding model molecules that mimic the transient interactions of potassium with binding sites of the selectivity filter during ion conduction. In addition to guide our experiments on the real system we have performed molecular dynamic-based simulations of the FTIR and 2DIR spectra of the entire KcsA complex, which is the largest comp...

  20. Flow Injection Analysis of Mercury Using 4-(Dimethylamino Benzaldehyde-4-Ethylthiosemicarbazone as the Ionophore of a Coated Wire Electrode

    Directory of Open Access Journals (Sweden)

    Sulaiman Ab Ghani

    2012-11-01

    Full Text Available A flow injection analysis (FIA incorporating a thiosemicarbazone-based coated wire electrode (CWE was developed method for the determination of mercury(II. A 0.1 M KNO3 carrier stream with pH between 1 and 5 and flow rate of 1 mL·min−1 were used as optimum parameters. A linear plot within the concentration range of 5 × 10−6–0.1 M Hg(II, slope of 27.8 ± 1 mV per decade and correlation coefficient (R2 of 0.984 were obtained. The system was successfully applied for the determination of mercury(II in dental amalgam solutions and spiked environmental water samples. Highly reproducible measurements with relative standard deviation (RSD < 1% (n = 3 were obtained, giving a typical throughput of 30 samples·h−1.

  1. Optimizing potentiometric ionophore and electrode design for environmental on-site control of antibiotic drugs: application to sulfamethoxazole.

    Science.gov (United States)

    Almeida, S A A; Truta, Liliana A A N A; Queirós, Raquel B; Montenegro, M C B S M; Cunha, Alexandre L; Sales, M G F

    2012-05-15

    Potentiometric sensors are typically unable to carry out on-site monitoring of environmental drug contaminants because of their high limits of detection (LODs). Designing a novel ligand material for the target analyte and managing the composition of the internal reference solution have been the strategies employed here to produce for the first time a potentiometric-based direct reading method for an environmental drug contaminant. This concept has been applied to sulfamethoxazole (SMX), one of the many antibiotics used in aquaculture practices that may occur in environmental waters. The novel ligand has been produced by imprinting SMX on the surface of graphitic carbon nanostructures (CN)environmental water. The best membrane cocktail was applied on the smaller end of a 1000 μL micropipette tip made of polypropylene. The tip was then filled with inner reference solution containing SMX and chlorate (as interfering compound). The corresponding concentrations were studied for 1 × 10(-5) to 1 × 10(-10) and 1 × 10(-3) to 1 × 10(-8)mol/L. The best condition allowed the detection of 5.92 ng/L (or 2.3 × 10(-8)mol/L) SMX for a sub-Nernstian slope of -40.3 mV/decade from 5.0 × 10(-8) to 2.4 × 10(-5)mol/L. The described sensors were found promising devices for field applications. The good selectivity of the sensory materials together with a carefully selected composition for the inner reference solution allowed LODs near the nanomolar range. Both solid-contact and "pipette tip"-based sensors were successfully applied to the analysis of aquaculture waters.

  2. Multiple sparse volumetric priors for distributed EEG source reconstruction.

    Science.gov (United States)

    Strobbe, Gregor; van Mierlo, Pieter; De Vos, Maarten; Mijović, Bogdan; Hallez, Hans; Van Huffel, Sabine; López, José David; Vandenberghe, Stefaan

    2014-10-15

    We revisit the multiple sparse priors (MSP) algorithm implemented in the statistical parametric mapping software (SPM) for distributed EEG source reconstruction (Friston et al., 2008). In the present implementation, multiple cortical patches are introduced as source priors based on a dipole source space restricted to a cortical surface mesh. In this note, we present a technique to construct volumetric cortical regions to introduce as source priors by restricting the dipole source space to a segmented gray matter layer and using a region growing approach. This extension allows to reconstruct brain structures besides the cortical surface and facilitates the use of more realistic volumetric head models including more layers, such as cerebrospinal fluid (CSF), compared to the standard 3-layered scalp-skull-brain head models. We illustrated the technique with ERP data and anatomical MR images in 12 subjects. Based on the segmented gray matter for each of the subjects, cortical regions were created and introduced as source priors for MSP-inversion assuming two types of head models. The standard 3-layered scalp-skull-brain head models and extended 4-layered head models including CSF. We compared these models with the current implementation by assessing the free energy corresponding with each of the reconstructions using Bayesian model selection for group studies. Strong evidence was found in favor of the volumetric MSP approach compared to the MSP approach based on cortical patches for both types of head models. Overall, the strongest evidence was found in favor of the volumetric MSP reconstructions based on the extended head models including CSF. These results were verified by comparing the reconstructed activity. The use of volumetric cortical regions as source priors is a useful complement to the present implementation as it allows to introduce more complex head models and volumetric source priors in future studies.

  3. Colorization by classifying the prior knowledge

    Institute of Scientific and Technical Information of China (English)

    DU Weiwei

    2011-01-01

    When a one-dimensional luminance scalar is replaced by a vector of a colorful multi-dimension for every pixel of a monochrome image,the process is called colorization.However,colorization is under-constrained.Therefore,the prior knowledge is considered and given to the monochrome image.Colorization using optimization algorithm is an effective algorithm for the above problem.However,it cannot effectively do with some images well without repeating experiments for confirming the place of scribbles.In this paper,a colorization algorithm is proposed,which can automatically generate the prior knowledge.The idea is that firstly,the prior knowledge crystallizes into some points of the prior knowledge which is automatically extracted by downsampling and upsampling method.And then some points of the prior knowledge are classified and given with corresponding colors.Lastly,the color image can be obtained by the color points of the prior knowledge.It is demonstrated that the proposal can not only effectively generate the prior knowledge but also colorize the monochrome image according to requirements of user with some experiments.

  4. 基于先验知识和纹理方向性的车标定位方法%VEHICLE-LOGO LOCATING METHOD BASED ON PRIOR KNOWLEDGE AND TEXTURE DIRECTIONALITY

    Institute of Scientific and Technical Information of China (English)

    王建; 任明武

    2014-01-01

    Based on the prior knowledge and according to the relative position relationship of vehicle licence plate and vehicle-logo,first we make rough positioning of the vehicle logo and get a rectangular rough location region containing the vehicle-logo image.In order to utilise the texture directional feature of the vehicle-logo background cooling grills,we introduce the concept of texture direction measure.According to the texture measure,the textures of the grille are grouped into two categories:the horizontal-like texture and the vertical texture.In the stage of accurate location,we adopt different location algorithms in light of different texture categories respectively.For horizontal-like texture,we use dynamic templates to locate the boundary,this achieves sound location effects for sophisticated horizontal texture and complicated mesh texture;For vertical texture,we introduce the concept of edge granularity,it effectively removes the noises points outside the vehicle logo region and preserves entire information of the vehicle-logo its own.Experimental results show that the method in this paper has good robustness,it can fast and accurately locate the position of vehicle-logo,the average successful locating rate reaches 97%,and the average locating time is 22 ms in testing environment.This location efficiency and accuracy can meet the demand of real-time system.%基于先验知识,根据车牌与车标的相对位置关系,首先对车标进行粗定位,得到包含车标图案的矩形粗定位区域。为了利用车标背景散热片的纹理方向特征,引入纹理方向测度的概念。根据纹理测度将散热片纹理分为两大类:类水平纹理和垂直纹理。在精定位阶段,对于不同的纹理类型采用不同的定位方法:对于类水平纹理,采用动态模板定位边界,对复杂水平纹理和复杂网状纹理具有良好的定位效果;对于垂直纹理,引入边缘颗粒度的概念,既有效地消除非

  5. Impact of prior authorization on the use and costs of lipid-lowering medications among Michigan and Indiana dual enrollees in Medicaid and Medicare: results of a longitudinal, population-based study.

    Science.gov (United States)

    Lu, Christine Y; Law, Michael R; Soumerai, Stephen B; Graves, Amy Johnson; LeCates, Robert F; Zhang, Fang; Ross-Degnan, Dennis; Adams, Alyce S

    2011-01-01

    Some Medicaid programs have adopted prior-authorization (PA) policies that require prescribers to request approval from Medicaid before prescribing drugs not included on a preferred drug list. This study examined the association between PA policies for lipid-lowering agents in Michigan and Indiana and the use and cost of this drug class among dual enrollees in Medicare and Medicaid. Michigan and Indiana claims data from the Centers for Medicare and Medicaid Services were assessed. Michigan Medicaid instituted a PA requirement for several lipid-lowering medications in March 2002; Indiana implemented a PA policy for drugs in this class in September 2002. Although the PA policies affected some statins, they predominantly targeted second-line treatments, including bile acid sequestrants, fibrates, and niacins. Individuals aged ≥18 years who were continuously dually enrolled in both Medicare and Medicaid from July 2000 through September 2003 were included in this longitudinal, population-based study, which included a 20-month observation period before the implementation of PA in Michigan and a 12-month follow-up period after the Indiana PA policy was initiated. Interrupted time series analysis was used to examine changes in prescription rates and pharmacy costs for lipid-lowering drugs before and after policy implementation. A total of 38,684 dual enrollees in Michigan and 29,463 in Indiana were included. Slightly more than half of the cohort were female (Michigan, 53.3% [20,614/38,684]; Indiana, 56.3% [16,595/29,463]); nearly half were aged 45 to 64 years (Michigan, 43.7% [16,921/38,684]; Indiana, 45.2% [13,321/29,463]). Most subjects were white (Michigan, 77.4% [29,957/38,684]; Indiana: 84.9% [25,022/29,463]). The PA policy was associated with an immediate 58% reduction in prescriptions for nonpreferred medications in Michigan and a corresponding increase in prescriptions for preferred agents. However, the PA policy had no apparent effect in Indiana, where there had

  6. Seismicity prior to the 2016 Kumamoto earthquakes

    CERN Document Server

    Nanjo, K Z; Orihara, Y; Furuse, N; Togo, S; Nitta, H; Okada, T; Tanaka, R; Kamogawa, M; Nagao, T

    2016-01-01

    The 2016 Kumamoto earthquakes occurred under circumstance that seismicity remains high in all parts of Japan since the 2011 Tohoku-Oki earthquake. Identifying what happened before this incident is one starting point for promote earthquake forecast research to prepare for subsequent large earthquakes in the near future in Japan. Here we report precursory seismic patterns prior to the Kumamoto earthquakes, measured by four different methods based on seismicity changes that can be used for earthquake forecasting: b-value method, two kinds of seismic quiescence evaluation methods, and a method of detailed foreshock evaluation. The spatial extent of precursory patterns differs from one method to the other and ranges from local scales (typically asperity size), to regional scales (e.g., 2{\\deg} x 3{\\deg} around the source zone). The earthquakes are preceded by periods of pronounced anomalies, which lasted decade scales (e.g., 20 years or longer) to yearly scales (e.g., 1~2 years). We demonstrate that combination of...

  7. A Simulation of Pell Grant Awards and Costs Using Prior-Prior Year Financial Data

    Science.gov (United States)

    Kelchen, Robert; Jones, Gigi

    2015-01-01

    We examine the likely implications of switching from a prior year (PY) financial aid system, the current practice in which students file the Free Application for Federal Student Aid (FAFSA) using income data from the previous tax year, to prior-prior year (PPY), in which data from two years before enrollment is used. While PPY allows students to…

  8. Prior Computer-Related Experiences and Hypermedia Metacognition.

    Science.gov (United States)

    Reed, W. Michael; Giessler, Steven F.

    1995-01-01

    Discusses the relationship between prior computer experiences and the linear or nonlinear steps students choose when working with hypermedia environments and time spent on task (based on a study of graduate students). Experience with content-area software, word processing, databases, spreadsheets, programming, hypermedia, and authoring are…

  9. Prior Learning Assessment: How Institutions Use Portfolio Assessments

    Science.gov (United States)

    Klein-Collins, Becky; Hain, Patrick

    2009-01-01

    The term Prior Learning Assessment (PLA) refers not to a single kind of assessment but rather an entire family of assessment methods that can be used by institutions. Some of these methods are exam-based. In addition, there are other methods of PLA. One of the more innovative methods of offering PLA, however, is through the development of student…

  10. Idarucizumab for Reversal of Dabigatran Prior to Acute Surgery

    DEFF Research Database (Denmark)

    Rosenberg, Lene; Gerstrøm, Gustav; Nybo, Mads

    2017-01-01

    and acetylsalicylic acid. In this case, the decision to use idarucizumab was based on the clinical manifestations and other routine coagulation parameters, as the plasma dabigatran concentration was not available prior to administration. Due to challenges with the plasma dabigatran analysis and taking the safety...

  11. Prior Authorization of PMDs Demonstration - Status Update

    Data.gov (United States)

    U.S. Department of Health & Human Services — CMS implemented a Prior Authorization process for scooters and power wheelchairs for people with Fee-For-Service Medicare who reside in seven states with high...

  12. Inference with the Median of a Prior

    Directory of Open Access Journals (Sweden)

    Ali Mohammad-Djafari

    2006-06-01

    Full Text Available We consider the problem of inference on one of the two parameters of a probability distribution when we have some prior information on a nuisance parameter. When a prior probability distribution on this nuisance parameter is given, the marginal distribution is the classical tool to account for it. If the prior distribution is not given, but we have partial knowledge such as a fixed number of moments, we can use the maximum entropy principle to assign a prior law and thus go back to the previous case. In this work, we consider the case where we only know the median of the prior and propose a new tool for this case. This new inference tool looks like a marginal distribution. It is obtained by first remarking that the marginal distribution can be considered as the mean value of the original distribution with respect to the prior probability law of the nuisance parameter, and then, by using the median in place of the mean.

  13. Transferring visual prior for online object tracking.

    Science.gov (United States)

    Wang, Qing; Chen, Feng; Yang, Jimei; Xu, Wenli; Yang, Ming-Hsuan

    2012-07-01

    Visual prior from generic real-world images can be learned and transferred for representing objects in a scene. Motivated by this, we propose an algorithm that transfers visual prior learned offline for online object tracking. From a collection of real-world images, we learn an overcomplete dictionary to represent visual prior. The prior knowledge of objects is generic, and the training image set does not necessarily contain any observation of the target object. During the tracking process, the learned visual prior is transferred to construct an object representation by sparse coding and multiscale max pooling. With this representation, a linear classifier is learned online to distinguish the target from the background and to account for the target and background appearance variations over time. Tracking is then carried out within a Bayesian inference framework, in which the learned classifier is used to construct the observation model and a particle filter is used to estimate the tracking result sequentially. Experiments on a variety of challenging sequences with comparisons to several state-of-the-art methods demonstrate that more robust object tracking can be achieved by transferring visual prior.

  14. 3D electrical resistivity inversion using prior spatial shape constraints

    Institute of Scientific and Technical Information of China (English)

    Li Shu-Cai; Nie Li-Chao; Liu Bin; Song Jie; Liu Zheng-Yu; Su Mao-Xin; Xu Lei

    2013-01-01

    To minimize the number of solutions in 3D resistivity inversion, an inherent problem in inversion, the amount of data considered have to be large and prior constraints need to be applied. Geological and geophysical data regarding the extent of a geological anomaly are important prior information. We propose the use of shape constraints in 3D electrical resistivity inversion. Three weighted orthogonal vectors (a normal and two tangent vectors) were used to control the resistivity differences at the boundaries of the anomaly. The spatial shape of the anomaly and the constraints on the boundaries of the anomaly are thus established. We incorporated the spatial shape constraints in the objective function of the 3D resistivity inversion and constructed the 3D resistivity inversion equation with spatial shape constraints. Subsequently, we used numerical modeling based on prior spatial shape data to constrain the direction vectors and weights of the 3D resistivity inversion. We established a reasonable range between the direction vectors and weights, and verified the feasibility and effectiveness of using spatial shape prior constraints in reducing excessive structures and the number of solutions. We applied the prior spatially shape-constrained inversion method to locate the aquifer at the Guangzhou subway. The spatial shape constraints were taken from ground penetrating radar data. The inversion results for the location and shape of the aquifer agree well with drilling data, and the number of inversion solutions is significantly reduced.

  15. Placenta previa after prior abortion: a meta-analysis

    Directory of Open Access Journals (Sweden)

    Manoochehr Karami

    2017-07-01

    Full Text Available There is controversy regarding the role of prior abortion on placenta previa in subsequent pregnancies. We conducted an updated, comprehensive meta-analysis of placenta previa after prior abortion. The search was conducted from PubMed, Web of Science and Scopus databases from the database inception to January 31, 2017. The heterogeneity across studies was evaluated by Q-test and I2 statistical test. Publication bias was assessed by Begg's test and Egger's test. Results of odds ratio (OR estimates with their corresponding 95% confidence intervals (CI were pooled using random-effects modeling. The literature search included 872 articles up until January 2017 with 2,134,529 participants. Based on OR estimates obtained from case-control and cohort studies, we found a significant association between prior spontaneous abortions and placenta previa (1.77; 95% CI: 1.60, 1.94 and between prior induced abortions and placenta previa (1.36; 95% CI: 1.02, 1.69. The meta-analysis study herein showed that prior abortion is a risk factor for placenta previa.

  16. Antimicrobial agent triclosan is a proton ionophore uncoupler of mitochondria in living rat and human mast cells and in primary human keratinocytes.

    Science.gov (United States)

    Weatherly, Lisa M; Shim, Juyoung; Hashmi, Hina N; Kennedy, Rachel H; Hess, Samuel T; Gosse, Julie A

    2016-06-01

    Triclosan (TCS) is an antimicrobial used widely in hospitals and personal care products, at ~10 mm. Human skin efficiently absorbs TCS. Mast cells are ubiquitous key players both in physiological processes and in disease, including asthma, cancer and autism. We previously showed that non-cytotoxic levels of TCS inhibit degranulation, the release of histamine and other mediators, from rat basophilic leukemia mast cells (RBL-2H3), and in this study, we replicate this finding in human mast cells (HMC-1.2). Our investigation into the molecular mechanisms underlying this effect led to the discovery that TCS disrupts adenosine triphosphate (ATP) production in RBL-2H3 cells in glucose-free, galactose-containing media (95% confidence interval EC50 = 7.5-9.7 µm), without causing cytotoxicity. Using these same glucose-free conditions, 15 µm TCS dampens RBL-2H3 degranulation by 40%. The same ATP disruption was found with human HMC-1.2 cells (EC50 4.2-13.7 µm), NIH-3 T3 mouse fibroblasts (EC50 4.8-7.4 µm) and primary human keratinocytes (EC50 3.0-4.1 µm) all with no cytotoxicity. TCS increases oxygen consumption rate in RBL-2H3 cells. Known mitochondrial uncouplers (e.g., carbonyl cyanide 3-chlorophenylhydrazone) previously were found to inhibit mast cell function. TCS-methyl, which has a methyl group in place of the TCS ionizable proton, affects neither degranulation nor ATP production at non-cytotoxic doses. Thus, the effects of TCS on mast cell function are due to its proton ionophore structure. In addition, 5 µm TCS inhibits thapsigargin-stimulated degranulation of RBL-2H3 cells: further evidence that TCS disrupts mast cell signaling. Our data indicate that TCS is a mitochondrial uncoupler, and TCS may affect numerous cell types and functions via this mechanism. Copyright © 2015 John Wiley & Sons, Ltd.

  17. Data on NAEP 2011 writing assessment prior computer use

    OpenAIRE

    Tate, Tamara P.; Mark Warschauer; Jamal Abedi

    2016-01-01

    This data article contains information based on the 2011 National Assessment of Educational Progress in Writing Restricted-Use Data, available from the National Center for Education Statistics (NCES Pub. No. 2014476). https://nces.ed.gov/nationsreportcard/researchcenter/datatools.aspx. The data include the statistical relationships between survey reports of teachers and students regarding prior use of computers and other technology and writing achievement levels on the 2011 computer-based NAE...

  18. Prior implicit knowledge shapes human threshold for orientation noise

    DEFF Research Database (Denmark)

    Christensen, Jeppe H; Bex, Peter J; Fiser, József

    2015-01-01

    , resulting in an image-class-specific threshold that changes the shape and position of the dipper function according to image class. These findings do not fit a filter-based feed-forward view of orientation coding, but can be explained by a process that utilizes an experience-based perceptual prior...... of the expected local orientations and their noise. Thus, the visual system encodes orientation in a dynamic context by continuously combining sensory information with expectations derived from earlier experiences....

  19. Tuning your priors to the world.

    Science.gov (United States)

    Feldman, Jacob

    2013-01-01

    The idea that perceptual and cognitive systems must incorporate knowledge about the structure of the environment has become a central dogma of cognitive theory. In a Bayesian context, this idea is often realized in terms of "tuning the prior"-widely assumed to mean adjusting prior probabilities so that they match the frequencies of events in the world. This kind of "ecological" tuning has often been held up as an ideal of inference, in fact defining an "ideal observer." But widespread as this viewpoint is, it directly contradicts Bayesian philosophy of probability, which views probabilities as degrees of belief rather than relative frequencies, and explicitly denies that they are objective characteristics of the world. Moreover, tuning the prior to observed environmental frequencies is subject to overfitting, meaning in this context overtuning to the environment, which leads (ironically) to poor performance in future encounters with the same environment. Whenever there is uncertainty about the environment-which there almost always is-an agent's prior should be biased away from ecological relative frequencies and toward simpler and more entropic priors.

  20. Generative supervised classification using Dirichlet process priors.

    Science.gov (United States)

    Davy, Manuel; Tourneret, Jean-Yves

    2010-10-01

    Choosing the appropriate parameter prior distributions associated to a given bayesian model is a challenging problem. Conjugate priors can be selected for simplicity motivations. However, conjugate priors can be too restrictive to accurately model the available prior information. This paper studies a new generative supervised classifier which assumes that the parameter prior distributions conditioned on each class are mixtures of Dirichlet processes. The motivations for using mixtures of Dirichlet processes is their known ability to model accurately a large class of probability distributions. A Monte Carlo method allowing one to sample according to the resulting class-conditional posterior distributions is then studied. The parameters appearing in the class-conditional densities can then be estimated using these generated samples (following bayesian learning). The proposed supervised classifier is applied to the classification of altimetric waveforms backscattered from different surfaces (oceans, ices, forests, and deserts). This classification is a first step before developing tools allowing for the extraction of useful geophysical information from altimetric waveforms backscattered from nonoceanic surfaces.

  1. Correlated noise and prior models in electromagnetic flow tomography

    Science.gov (United States)

    Lehtikangas, Ossi; Vauhkonen, Marko

    2017-04-01

    Electromagnetic flow meters are a gold standard in measuring the mean flow velocity of conductive liquids and slurries in process industry. A drawback of this approach is that the velocity field cannot be determined. Information about velocity fields is important for characterizing multiphase flows in the process industry. Recently, electromagnetic flow tomography (EMFT) has been proposed for measuring velocity fields using several coils and a set of electrodes attached to the inner surface of the pipe. The velocity field reconstruction method utilizes a finite element based computational forward model and a Bayesian framework for inverse problem. In the approach, a priori probability and noise models are written describing the flow and measurement error characteristics, respectively. In this work, the effect of additive, possibly correlated, measurement noise and different prior models on the velocity field reconstructions in EMFT are tested using numerical simulations. The results show that the velocity field reconstruction method produces feasible estimates even with relatively high level of correlated measurement noise if the covariance structure of the noise is taken into account. In practice, the noise covariance can be estimated from measurements using sample based methods. Moreover, it is shown that a smoothness prior using a squared exponential covariance function is in general a good choice for the prior model and more advanced prior models for specific flow types such as stratified or turbulent flows can be used.

  2. Activities of enzymes that metabolize platelet-activating factor (1-alkyl-2-acetyl-sn-glycero-3-phosphocholine) in neutrophils and eosinophils from humans and the effect of a calcium ionophore

    Energy Technology Data Exchange (ETDEWEB)

    Lee, T. (Oak Ridge Associated Univ., TN); Malone, B.; Wasserman, S.I.; Fitzgerald, V.; Snyder, F.

    1982-04-29

    Enzymatic systems in human blood cells are described for the activation and inactivation of a biologically active phospholipid (l-alkyl-2-acetyl-sn-glycero-3-phosphocholine) with hypotensive, platelet-aggregating, and inflammatory properties. The results document the presence of alkyldihydroxyacetone-phosphate synthase (forms the O-alkyl linkage in lipids), l-alkyl-2-lyso-sn-glycero-3-phosphocholine:acetyl-CoA acetyltransferase (produces the biologically active molecule), and 1-alkyl-sn-glycero-3-phosphocholine: acetylhydrolase (destroys the biological activity) in human neutrophils and eosinophils. Both the acetyltransferase and acetylhydrolase activities are increased severalfold after treatment of normal neutrophils with ionophore A23187; however, alkyldihydroxyacetone-phosphate synthase activity is not influenced by the ionophore. Eosinophils isolated from patients with eosinophilia have significantly greater activities of all the enzymes studied than the eosinophils isolated from normal individuals. Our results indicate the acetyltransferase responsible for 1-alkyl-2-acetyl-sn-glycero-3-phospho-choline synthesis may serve an important role in human blood cells that release this biologically active phospholipid. Moreover, the acetyltransferase activity was found to be dramatically influenced by calcium flux.

  3. GENERAL ASPECTS REGARDING THE PRIOR DISCIPLINARY RESEARCH

    Directory of Open Access Journals (Sweden)

    ANDRA PURAN (DASCĂLU

    2012-05-01

    Full Text Available Disciplinary research is the first phase of the disciplinary action. According to art. 251 paragraph 1 of the Labour Code no disciplinary sanction may be ordered before performing the prior disciplinary research.These regulations provide an exception: the sanction of written warning. The current regulations in question, kept from the old regulation, provides a protection for employees against abuses made by employers, since sanctions are affecting the salary or the position held, or even the development of individual employment contract. Thus, prior research of the fact that is a misconduct, before a disciplinary sanction is applied, is an essential condition for the validity of the measure ordered. Through this study we try to highlight some general issues concerning the characteristics, processes and effects of prior disciplinary research.

  4. Commissioning of the PRIOR proton microscope

    CERN Document Server

    Varentsov, D; Bakhmutova, A; Barnes, C W; Bogdanov, A; Danly, C R; Efimov, S; Endres, M; Fertman, A; Golubev, A A; Hoffmann, D H H; Ionita, B; Kantsyrev, A; Krasik, Ya E; Lang, P M; Lomonosov, I; Mariam, F G; Markov, N; Merrill, F E; Mintsev, V B; Nikolaev, D; Panyushkin, V; Rodionova, M; Schanz, M; Schoenberg, K; Semennikov, A; Shestov, L; Skachkov, V S; Turtikov, V; Udrea, S; Vasylyev, O; Weyrich, K; Wilde, C; Zubareva, A

    2015-01-01

    Recently a new high energy proton microscopy facility PRIOR (Proton Microscope for FAIR) has been designed, constructed and successfully commissioned at GSI Helmholtzzentrum f\\"ur Schwerionenforschung (Darmstadt, Germany). As a result of the experiments with 3.5-4.5 GeV proton beams delivered by the heavy ion synchrotron SIS-18 of GSI, 30 um spatial and 10 ns temporal resolutions of the proton microscope have been demostrated. A new pulsed power setup for studying properties of matter under extremes has been developed for the dynamic commissioning of the PRIOR facility. This paper describes the PRIOR setup as well as the results of the first static and dynamic proton radiography experiments performed at GSI.

  5. Entropic Priors and Bayesian Model Selection

    CERN Document Server

    Brewer, Brendon J

    2009-01-01

    We demonstrate that the principle of maximum relative entropy (ME), used judiciously, can ease the specification of priors in model selection problems. The resulting effect is that models that make sharp predictions are disfavoured, weakening the usual Bayesian "Occam's Razor". This is illustrated with a simple example involving what Jaynes called a "sure thing" hypothesis. Jaynes' resolution of the situation involved introducing a large number of alternative "sure thing" hypotheses that were possible before we observed the data. However, in more complex situations, it may not be possible to explicitly enumerate large numbers of alternatives. The entropic priors formalism produces the desired result without modifying the hypothesis space or requiring explicit enumeration of alternatives; all that is required is a good model for the prior predictive distribution for the data. This idea is illustrated with a simple rigged-lottery example, and we outline how this idea may help to resolve a recent debate amongst ...

  6. Generative Prior Knowledge for Discriminative Classification

    CERN Document Server

    DeJong, G; 10.1613/jair.1934

    2011-01-01

    We present a novel framework for integrating prior knowledge into discriminative classifiers. Our framework allows discriminative classifiers such as Support Vector Machines (SVMs) to utilize prior knowledge specified in the generative setting. The dual objective of fitting the data and respecting prior knowledge is formulated as a bilevel program, which is solved (approximately) via iterative application of second-order cone programming. To test our approach, we consider the problem of using WordNet (a semantic database of English language) to improve low-sample classification accuracy of newsgroup categorization. WordNet is viewed as an approximate, but readily available source of background knowledge, and our framework is capable of utilizing it in a flexible way.

  7. Genome position specific priors for genomic prediction

    DEFF Research Database (Denmark)

    Brøndum, Rasmus Froberg; Su, Guosheng; Lund, Mogens Sandø

    2012-01-01

    population when using a prior derived from the Nordic Holstein population compared to using no prior information. These improvements were significant (PHotelling Williams t-test for protein- and fat yield Conclusion For some traits the method might be advantageous compared to pooling...... to estimate SNP effects, except in the case of fat yield. The small size of the Jersey validation set meant that these improvements in accuracy were not significant using a Hotelling-Williams t-test at the 5% level. An increase in accuracy of 1-2% for all traits was observed in the Australian Holstein...

  8. Numbers and prior knowledge in sentence comprehension

    Directory of Open Access Journals (Sweden)

    Pedro Macizo

    2013-01-01

    Full Text Available We evaluated whether the comprehension of sentences that contained numerical information could benefit from presenting numbers in Arabic format and from using prior knowledge. Participants read sentences including numbers (Arabic digits or number words while the comprehension accuracy was evaluated. In addition, the sentences were biased or unbiased by people's prior knowledge about quantities. The results showed better comprehension for sentences that contained Arabic digits as compared to number words. Moreover, biased sentences were understood more accurately than unbiased sentences. These results indicate that information about magnitude in sentence context is comprehended better when quantities are presented in Arabic format and when they are associated with participants' world knowledge.

  9. 基于暗原色先验去雾的改进型算法研究%The Study of the Improved Algorithm for Haze Removal Based on Dark Channel Prior

    Institute of Scientific and Technical Information of China (English)

    蔡云

    2015-01-01

    分析讨论了原暗原色先验去雾技术,提出暗原色去雾算法的改进.针对在雾天情况下能见度很低,论文先根据暗原色先验得到雾天图像的每个小区域的最暗点,以这些点作为置信点,通过把这些置信点扩展膨胀来得到整幅图像的深度图,最后得到清晰的图像.采用理论推导和公式演算的方法,对改进型去雾算法的理论进行了分析,通过将原有的暗原色去雾算法与改进型去雾算法从理论上和实验结果的仿真上进行了比较,从而验证了改进型去雾算法的可行性和一定程度上的高效性.%Analysis and discussion of the original dark channel prior technology, improved dark channel defogging algorithm. Ac-cording to thevisibility in the fogcondition is very low, firstly, according to the dark channel prior to obtain the mostdarkfoggy images of each small area, with these points as confidence, by putting these confidence point through the expansion of expan-sion to obtain the depth map of the whole image. used theory is derived and formula calculus of method, on improved type to fog algorithm of theory for has analysis, in analysis introduced of process in the, will original of dark primaries to fog algorithm and improved type to fog algorithm for has theory of compared and experiment results of simulation compared, obtained im-proved type to fog algorithm of superiority.

  10. PET image reconstruction using multi-parametric anato-functional priors

    Science.gov (United States)

    Mehranian, Abolfazl; Belzunce, Martin A.; Niccolini, Flavia; Politis, Marios; Prieto, Claudia; Turkheimer, Federico; Hammers, Alexander; Reader, Andrew J.

    2017-08-01

    In this study, we investigate the application of multi-parametric anato-functional (MR-PET) priors for the maximum a posteriori (MAP) reconstruction of brain PET data in order to address the limitations of the conventional anatomical priors in the presence of PET-MR mismatches. In addition to partial volume correction benefits, the suitability of these priors for reconstruction of low-count PET data is also introduced and demonstrated, comparing to standard maximum-likelihood (ML) reconstruction of high-count data. The conventional local Tikhonov and total variation (TV) priors and current state-of-the-art anatomical priors including the Kaipio, non-local Tikhonov prior with Bowsher and Gaussian similarity kernels are investigated and presented in a unified framework. The Gaussian kernels are calculated using both voxel- and patch-based feature vectors. To cope with PET and MR mismatches, the Bowsher and Gaussian priors are extended to multi-parametric priors. In addition, we propose a modified joint Burg entropy prior that by definition exploits all parametric information in the MAP reconstruction of PET data. The performance of the priors was extensively evaluated using 3D simulations and two clinical brain datasets of [18F]florbetaben and [18F]FDG radiotracers. For simulations, several anato-functional mismatches were intentionally introduced between the PET and MR images, and furthermore, for the FDG clinical dataset, two PET-unique active tumours were embedded in the PET data. Our simulation results showed that the joint Burg entropy prior far outperformed the conventional anatomical priors in terms of preserving PET unique lesions, while still reconstructing functional boundaries with corresponding MR boundaries. In addition, the multi-parametric extension of the Gaussian and Bowsher priors led to enhanced preservation of edge and PET unique features and also an improved bias-variance performance. In agreement with the simulation results, the clinical results

  11. Action priors for learning domain invariances

    CSIR Research Space (South Africa)

    Rosman, Benjamin S

    2015-04-01

    Full Text Available , defined as distributions over the action space, conditioned on environment state, and show how these can be learnt from a set of value functions. We apply action priors in the setting of reinforcement learning, to bias action selection during exploration...

  12. Recognition of Prior Learning: The Participants' Perspective

    Science.gov (United States)

    Miguel, Marta C.; Ornelas, José H.; Maroco, João P.

    2016-01-01

    The current narrative on lifelong learning goes beyond formal education and training, including learning at work, in the family and in the community. Recognition of prior learning is a process of evaluation of those skills and knowledge acquired through life experience, allowing them to be formally recognized by the qualification systems. It is a…

  13. The prior statistics of object colors

    NARCIS (Netherlands)

    Koenderink, J.J.

    2010-01-01

    The prior statistics of object colors is of much interest because extensive statistical investigations of reflectance spectra reveal highly non-uniform structure in color space common to several very different databases. This common structure is due to the visual system rather than to the statistics

  14. Models for Validation of Prior Learning (VPL)

    DEFF Research Database (Denmark)

    Ehlers, Søren

    would have been categorized as utopian can become realpolitik. Validation of Prior Learning (VPL) was in Europe mainly regarded as utopian while universities in the United States of America (USA) were developing ways to obtain credits to those students which was coming with experiences from working life....

  15. Offending prior to first psychiatric contact

    DEFF Research Database (Denmark)

    Stevens, H; Agerbo, E; Dean, K

    2012-01-01

    There is a well-established association between psychotic disorders and subsequent offending but the extent to which those who develop psychosis might have a prior history of offending is less clear. Little is known about whether the association between illness and offending exists in non-psychot...

  16. Objective prior distribution of climate sensitivity

    Science.gov (United States)

    Pueyo, S.

    2012-04-01

    The problems posed by the choice of prior distribution constitute one of the most fundamental obstacles to assign probabilities to the possible values of climate sensitivity S. The prior is the probability distribution that we assume before introducing data. In the literature about climate sensitivity, the most frequently used prior is the uniform. On first inspection, this distribution would seem to represent absence of information, but, as is well known, this assumption leads to paradoxes. This observation has led to the widespread belief that priors are inherently subjective and should be decided by expert elicitation, even though this amounts to questioning the objective value of scientific results. In general, the climate science community is unaware of the "objective Bayesian" literature, which seeks objective criteria to determine non-informative prior distributions (or reference priors). In a recent paper (Pueyo 2011) I applied an objective Bayesian approach to climate sensitivity. I described three lines of evidence indicating that the distribution that really represents absence of information about S is log-uniform, i.e. it consists of a uniform distribution of log(S) instead of S: • In the case of S, only the log-uniform distribution satisfies Jaynes' invariant groups criterion, i.e. this distribution does not change when modifying assumptions that are not explicitly included in the enunciate of the problem (I only included the definition of S). • In terms of information theory, information about S can be identified with mutual information between changes in radiative forcing and in temperature. Absence of mutual information between these variables implies a log-uniform distribution of S. • The frequency distribution of sets of parameters formally comparable to climate sensitivity is approximately log-uniform for a broad range of values. A log-uniform distribution of S is intermediate between a uniform distribution of S and a uniform distribution

  17. Digital communication constraints in prior space missions

    Science.gov (United States)

    Yassine, Nathan K.

    2004-01-01

    Digital communication is crucial for space endeavors. Jt transmits scientific and command data between earth stations and the spacecraft crew. It facilitates communications between astronauts, and provides live coverage during all phases of the mission. Digital communications provide ground stations and spacecraft crew precise data on the spacecraft position throughout the entire mission. Lessons learned from prior space missions are valuable for our new lunar and Mars missions set by our president s speech. These data will save our agency time and money, and set course our current developing technologies. Limitations on digital communications equipment pertaining mass, volume, data rate, frequency, antenna type and size, modulation, format, and power in the passed space missions are of particular interest. This activity is in support of ongoing communication architectural studies pertaining to robotic and human lunar exploration. The design capabilities and functionalities will depend on the space and power allocated for digital communication equipment. My contribution will be gathering these data, write a report, and present it to Communications Technology Division Staff. Antenna design is very carefully studied for each mission scenario. Currently, Phased array antennas are being developed for the lunar mission. Phased array antennas use little power, and electronically steer a beam instead of DC motors. There are 615 patches in the phased array antenna. These patches have to be modified to have high yield. 50 patches were created for testing. My part is to assist in the characterization of these patch antennas, and determine whether or not certain modifications to quartz micro-strip patch radiators result in a significant yield to warrant proceeding with repairs to the prototype 19 GHz ferroelectric reflect-array antenna. This work requires learning how to calibrate an automatic network, and mounting and testing antennas in coaxial fixtures. The purpose of this

  18. Video Contents Prior Storing Server For Lte Networks

    Directory of Open Access Journals (Sweden)

    Tony Tsang

    2015-10-01

    Full Text Available One of the most important multimedia applications is Internet protocol TV (IPTV for next-generation networks. IPTV provides triple-play services that require high-speed access networks with the functions of multicasting and quality of service (QoS guarantees. Among 4G mobile ac-cess networks, LTE networks are regarded as among the best solutions to meet higher bandwidth demands. In this paper, we propose a new architecture for multicasting live IPTV traffic in 4G LTE networks. The proposed mechanism involves assigning a unique logical link identifier to each IPTV channel. To manage multicasting, a prior storing server in the Base Station and in each mobile network unit, mobile phone, is constructed. In this work, we propose a partial prior storing strategy that considers the changes in the popularity of the video content segments over time and the access patterns of the users to compute the utility of the objects in the prior storage. We also propose to partition the prior storage to avoid the eviction of the popular objects (those not accessed frequently by the unpopular ones which are accessed with higher frequency. The popularity distribution and ageing of popularity are measured from two online datasets and use the parameters in simulations. Simulation results show that our proposed architecture can improve the system performance and QoS parameters in terms of packet delay, jitter and packet loss.

  19. A Selective Membrane Electrode for Thiocyanate Ion Based on a Bis-taurine-salicylic Binuclear Copper(Ⅱ) Complex as Ionophore

    Institute of Scientific and Technical Information of China (English)

    王福昌; 柴雅琴; 袁若; 陈春华; 戴建远; 徐岚

    2005-01-01

    The response characteristics of a new potentiometric membrane electrode with unique selectivity towards thiocyanate ion were reported. The electrode was prepared by incorporating bis-taurine-salicylic binuclear copper(Ⅱ) complex into a plasticized PVC-membrane. The resulting electrode exhibits anti-Hofmeister selectivity sequence: SCN->I-> ClO4- >Sal-> NO3- > NO2- >Br->Cl-> SO3- > SO42- and a near-Nernstian potential linear range for thiocyanate from 1.0×10-1 to 1.0× 10-6 mol·L-1 with a detection limit of 8.0× 10-7 mol·L-1 and a slope of - 56.5 mV/PCSCN- in phosphate buffer solution of pH 5.0 at 20 ℃. The UV/Vis spectra, IR spectroscopy and AC impedance studies showed that the excellent selectivity to thiocyanate was related to the unique interaction between the central metal and the analyte and a steric effect associated with the structure of the carrier. The electrode was successfully applied to the determination of thiocyanate in waste water and human urine samples.

  20. de Finetti Priors using Markov chain Monte Carlo computations.

    Science.gov (United States)

    Bacallado, Sergio; Diaconis, Persi; Holmes, Susan

    2015-07-01

    Recent advances in Monte Carlo methods allow us to revisit work by de Finetti who suggested the use of approximate exchangeability in the analyses of contingency tables. This paper gives examples of computational implementations using Metropolis Hastings, Langevin and Hamiltonian Monte Carlo to compute posterior distributions for test statistics relevant for testing independence, reversible or three way models for discrete exponential families using polynomial priors and Gröbner bases.

  1. Method of classify identification of group technology based on the diffuse prior distribution%基于扩散先验分布的成组技术分类识别方法

    Institute of Scientific and Technical Information of China (English)

    唐宁; 蔡晋; 李原; 张开富

    2012-01-01

    The classify identification is one of the most widely used methods of statistical analysis. The classify identification is used to explain the geometric model of object by matching geometric features and the description of features. To obtain the features of productions is the key point of the classify identification. In view of part-equipment group optimized network model, a method of Bayesian inference is given. These studies classify the parts and equipments by the diffuse prior distribution of Bayesian inference classification. According to the judgment of forecast density function of sample, the posterior probability ratio and the identification rules to classify the samples are set.%分类识别方法是实际应用中最为广泛的统计分析方法之一,特征识别是对对象几何模型进行解释,通过匹配几何特征部分与特征的形式描述来实现.提取产品特征信息是特征识别的难点.结合零件-设备成组优化的网络模型,提出一种基于贝叶斯推理的扩散先验分布的识别算法.依据成组技术的零件分类编码系统对零件设备进行成组分类,通过扩散先验分布的贝叶斯推理分类识别方法,根据待判别样品的预报密度函数,建立后验概率比和分类识别规则,对待识别样本进行判别分类.

  2. Identification of genes involved in Ca2+ ionophore A23187-mediated apoptosis and demonstration of a high susceptibility for transcriptional repression of cell cycle genes in B lymphoblasts from a patient with Scott syndrome

    Directory of Open Access Journals (Sweden)

    Meyer Dominique

    2005-10-01

    Full Text Available Abstract Background In contrast to other agents able to induce apoptosis of cultured cells, Ca2+ ionophore A23187 was shown to elicit direct activation of intracellular signal(s. The phenotype of the cells derived from patients having the hemorrhagic disease Scott syndrome, is associated with an abnormally high proportion of apoptotic cells, both in basal culture medium and upon addition of low ionophore concentrations in long-term cultures. These features are presumably related to the mutation also responsible for the defective procoagulant plasma membrane remodeling. We analyzed the specific transcriptional re-programming induced by A23187 to get insights into the effect of this agent on gene expression and a defective gene regulation in Scott cells. Results The changes in gene expression upon 48 hours treatment with 200 nM A23187 were measured in Scott B lymphoblasts compared to B lymphoblasts derived from the patient's daughter or unrelated individuals using Affymetrix microarrays. In a similar manner in all of the B cell lines, results showed up-regulation of 55 genes, out of 12,000 represented sequences, involved in various pathways of the cell metabolism. In contrast, a group of 54 down-regulated genes, coding for histones and proteins involved in the cell cycle progression, was more significantly repressed in Scott B lymphoblasts than in the other cell lines. These data correlated with the alterations of the cell cycle phases in treated cells and suggested that the potent effect of A23187 in Scott B lymphoblasts may be the consequence of the underlying molecular defect. Conclusion The data illustrate that the ionophore A23187 exerts its pro-apoptotic effect by promoting a complex pattern of genetic changes. These results also suggest that a subset of genes participating in various steps of the cell cycle progress can be transcriptionally regulated in a coordinated fashion. Furthermore, this research brings a new insight into the defect

  3. Variational segmentation problems using prior knowledge in imaging and vision

    DEFF Research Database (Denmark)

    Fundana, Ketut

    -manifold of pose-invariant planar contours into both the Chan-Vese model and its convex formulation to segment an object of interest in a sequence of images. We apply the models to track the viewpoint onto 3D rigid object. The prior-based object segmentation models encounter the problem of shape alignment, where......This dissertation addresses variational formulation of segmentation problems using prior knowledge. Variational models are among the most successful approaches for solving many Computer Vision and Image Processing problems. The models aim at finding the solution to a given energy functional defined...... to describe a Computer Vision task through energy minimization. Image segmentation, as an ill-posed problem, is still a major challenge in Computer Vision. Due to the presence of noise, clutter and occlusion, the use of image information alone often gives poor segmentation results. To overcome this problem...

  4. Prior image constrained compressed sensing: a quantitative performance evaluation

    Science.gov (United States)

    Thériault Lauzier, Pascal; Tang, Jie; Chen, Guang-Hong

    2012-03-01

    The appeal of compressed sensing (CS) in the context of medical imaging is undeniable. In MRI, it could enable shorter acquisition times while in CT, it has the potential to reduce the ionizing radiation dose imparted to patients. However, images reconstructed using a CS-based approach often show an unusual texture and a potential loss in spatial resolution. The prior image constrained compressed sensing (PICCS) algorithm has been shown to enable accurate image reconstruction at lower levels of sampling. This study systematically evaluates an implementation of PICCS applied to myocardial perfusion imaging with respect to two parameters of its objective function. The prior image parameter α was shown here to yield an optimal image quality in the range 0.4 to 0.5. A quantitative evaluation in terms of temporal resolution, spatial resolution, noise level, noise texture, and reconstruction accuracy was performed.

  5. Bayesian inference from count data using discrete uniform priors.

    Science.gov (United States)

    Comoglio, Federico; Fracchia, Letizia; Rinaldi, Maurizio

    2013-01-01

    We consider a set of sample counts obtained by sampling arbitrary fractions of a finite volume containing an homogeneously dispersed population of identical objects. We report a Bayesian derivation of the posterior probability distribution of the population size using a binomial likelihood and non-conjugate, discrete uniform priors under sampling with or without replacement. Our derivation yields a computationally feasible formula that can prove useful in a variety of statistical problems involving absolute quantification under uncertainty. We implemented our algorithm in the R package dupiR and compared it with a previously proposed Bayesian method based on a Gamma prior. As a showcase, we demonstrate that our inference framework can be used to estimate bacterial survival curves from measurements characterized by extremely low or zero counts and rather high sampling fractions. All in all, we provide a versatile, general purpose algorithm to infer population sizes from count data, which can find application in a broad spectrum of biological and physical problems.

  6. A Case Study of Peer Educators in a Community-Based Program to Reduce Teen Pregnancy: Selected Characteristics Prior to Training, Perceptions of Training and Work, and Perceptions of How Participation in the Program Has Affected Them

    Science.gov (United States)

    Beshers, Sarah C.

    2007-01-01

    This investigation is a case study of peer educators in a community-based teen pregnancy prevention program. Research questions focused on identifying ways in which peer educators differed from other teens and exploring the perceptions of the peer educators about their experience in the program and the ways in which it has affected them. Data were…

  7. The Influence of Prior Knowledge, University Coursework, and Field Experience on Primary Preservice Teachers' Use of Reading Comprehension Strategies in a Year-Long, Field-Based Teacher Education Program

    Science.gov (United States)

    Sampson, Mary Beth; Linek, Wayne M.; Raine, I. Laverne; Szabo, Susan

    2013-01-01

    This descriptive study employed mixed methods to explore preservice teachers' initial knowledge and subsequent use of explicitly taught reading comprehension strategies in primary grade classrooms during a year-long, field-based teacher preparation program. Self-Knowledge Rating Surveys, Strategy Multiple-Choice Tests, strategy logs, lesson plans,…

  8. A Habermasian Analysis of a Process of Recognition of Prior Learning for Health Care Assistants

    Science.gov (United States)

    Sandberg, Fredrik

    2012-01-01

    This article discusses a process of recognition of prior learning for accreditation of prior experiential learning to qualify for course credits used in an adult in-service education program for health care assistants at the upper-secondary level in Sweden. The data are based on interviews and observations drawn from a field study, and Habermas's…

  9. A Habermasian Analysis of a Process of Recognition of Prior Learning for Health Care Assistants

    Science.gov (United States)

    Sandberg, Fredrik

    2012-01-01

    This article discusses a process of recognition of prior learning for accreditation of prior experiential learning to qualify for course credits used in an adult in-service education program for health care assistants at the upper-secondary level in Sweden. The data are based on interviews and observations drawn from a field study, and Habermas's…

  10. Noise decaying of seismic data by Steerable Pyramid decomposition based on Laplace prior%Steerable Pyramid分解地震随机噪声衰减——基于局部Laplace先验概率密度模型

    Institute of Scientific and Technical Information of China (English)

    林春; 王绪本; 刘力辉

    2012-01-01

    The basic principle of decomposition and construction of Steerable Pyramid, which has multi-scale and multi-direction char-acteristics is introduced. It is applied in the random noise decaying of seismic data based on softLMAP threshold, and emulation and re-al data processing are given. The effect of noise decaying of Steerable Pyramid decomposition based on softLMAP threshold is com-pared with that of adaptive BayesShrink threshold and wavelet transform based on softLMAP threshold. The results prove that Steer-able Pyramid transform based on softLMAP threshold can relatively completely remove the noise while the edge of picture keeps well and the detail part also keeps at the same time. The result of noise decaying is good and easy to realize, so that Steerable Pyramid de-composition has the feasibility and prospect in the seismic data process.%简单介绍了具有多尺度与多方向性特点的Steerable Pyramid分解和重构的基本原理.采用softLMAP阈值将其应用于地震数据随机噪声衰减中,进行了仿真计算和实际资料的处理并与自适应BayesShrink阈值及小波域softLMAP阈值去噪进行比较.结果证明利用Steerable Pyramid分解softMAP阈值能比较彻底地去掉噪声,去噪后的图像边缘保持良好,滤除噪声同时还保留了有效部分,去噪效果良好,且易于实现,在地震资料处理中具有一定的可行性和应用前景.

  11. Investigating different approaches to develop informative priors in hierarchical Bayesian safety performance functions.

    Science.gov (United States)

    Yu, Rongjie; Abdel-Aty, Mohamed

    2013-07-01

    The Bayesian inference method has been frequently adopted to develop safety performance functions. One advantage of the Bayesian inference is that prior information for the independent variables can be included in the inference procedures. However, there are few studies that discussed how to formulate informative priors for the independent variables and evaluated the effects of incorporating informative priors in developing safety performance functions. This paper addresses this deficiency by introducing four approaches of developing informative priors for the independent variables based on historical data and expert experience. Merits of these informative priors have been tested along with two types of Bayesian hierarchical models (Poisson-gamma and Poisson-lognormal models). Deviance information criterion (DIC), R-square values, and coefficients of variance for the estimations were utilized as evaluation measures to select the best model(s). Comparison across the models indicated that the Poisson-gamma model is superior with a better model fit and it is much more robust with the informative priors. Moreover, the two-stage Bayesian updating informative priors provided the best goodness-of-fit and coefficient estimation accuracies. Furthermore, informative priors for the inverse dispersion parameter have also been introduced and tested. Different types of informative priors' effects on the model estimations and goodness-of-fit have been compared and concluded. Finally, based on the results, recommendations for future research topics and study applications have been made.

  12. [Registration of prehabilitation prior to surgery].

    Science.gov (United States)

    Tønnesen, Hanne; Duus, Benn R

    2008-04-21

    Four to eight week prehabilitation programs for smokers and harmful drinkers were included in the national guidelines in 2001. In October 2007 a guarantee for surgery within one month of waiting time came into effect in Denmark. The present Danish patient administration system already contains room for registration of prehabilitation prior to surgery. Using one specific code for prehabilitation at the surgical department and another for prehabilitation at other departments will enable correct registration. Thereby, it is possible to differentiate between ordinary waiting time before surgery and time for prehabilitation.

  13. Postnatal Care Service Utilization and Associated Factors among Women Who Gave Birth in the Last 12 Months prior to the Study in Debre Markos Town, Northwestern Ethiopia: A Community-Based Cross-Sectional Study

    Directory of Open Access Journals (Sweden)

    Miteku Andualem Limenih

    2016-01-01

    Full Text Available Improving maternal and newborn health through proper postnatal care services under the care of skilled health personnel is the key strategy to reduce maternal and neonatal mortality. However, there were limited evidences on utilization of postnatal care services in Ethiopia. A community based cross-sectional study was conducted in Debremarkos town, Northwest Ethiopia. Cluster sampling technique was used to select 588 study participants. Bivariate and multivariable logistic regression model was fitted to identify factors associated with postnatal care utilization. Odds ratio with 95% confidence interval was computed to determine the level of significance. Postnatal care service utilization was found to be 33.5%. Awareness about maternal complication (AOR: 2.72, 95% CI (1.71, 4.34, place of delivery of last child (AOR: 1.68, 95% CI: (1.01, 2.79, outcome of birth (AOR: 2.71, 95% CI (1.19, 6.19, delivery by cesarean section (AOR: 4.82, 95% CI (1.86, 12.54, and delivery complication that occurred during birth (AOR: 2.58, 95% CI (1.56, 4.28 were factors associated with postnatal care service utilization. Postnatal care service utilization was found to be low. Increasing awareness about postnatal care, preventing maternal and neonatal complication, and scheduling mothers based on the national postnatal care follow-up protocol would increase postnatal care service utilization.

  14. Tensors, BICEP2, prior dependence, and dust

    CERN Document Server

    Cortês, Marina; Parkinson, David

    2014-01-01

    We investigate the prior dependence on the inferred spectrum of primordial tensor perturbations, in light of recent results from BICEP2 and taking into account a possible dust contribution to polarized anisotropies. We highlight an optimized parameterization of the tensor power spectrum, and adoption of a logarithmic prior on its amplitude $A_T$, leading to results that transform more evenly under change of pivot scale. In the absence of foregrounds the tension between the results of BICEP2 and Planck drives the tensor spectral index $n_T$ to be blue-tilted in a joint analysis, which would be in contradiction to the standard inflation prediction ($n_T<0$). When foregrounds are accounted for, the BICEP2 results no longer require non-standard inflationary parameter regions. We present limits on primordial $A_T$ and $n_T$, adopting foreground scenarios put forward by Mortonson & Seljak and motivated by Planck 353 GHz observations, and assess what dust contribution leaves a detectable cosmological signal. ...

  15. A Single Image Dehazing Method Using Average Saturation Prior

    Directory of Open Access Journals (Sweden)

    Zhenfei Gu

    2017-01-01

    Full Text Available Outdoor images captured in bad weather are prone to yield poor visibility, which is a fatal problem for most computer vision applications. The majority of existing dehazing methods rely on an atmospheric scattering model and therefore share a common limitation; that is, the model is only valid when the atmosphere is homogeneous. In this paper, we propose an improved atmospheric scattering model to overcome this inherent limitation. By adopting the proposed model, a corresponding dehazing method is also presented. In this method, we first create a haze density distribution map of a hazy image, which enables us to segment the hazy image into scenes according to the haze density similarity. Then, in order to improve the atmospheric light estimation accuracy, we define an effective weight assignment function to locate a candidate scene based on the scene segmentation results and therefore avoid most potential errors. Next, we propose a simple but powerful prior named the average saturation prior (ASP, which is a statistic of extensive high-definition outdoor images. Using this prior combined with the improved atmospheric scattering model, we can directly estimate the scene atmospheric scattering coefficient and restore the scene albedo. The experimental results verify that our model is physically valid, and the proposed method outperforms several state-of-the-art single image dehazing methods in terms of both robustness and effectiveness.

  16. Bayesian Parallel Imaging With Edge-Preserving Priors

    Science.gov (United States)

    Raj, Ashish; Singh, Gurmeet; Zabih, Ramin; Kressler, Bryan; Wang, Yi; Schuff, Norbert; Weiner, Michael

    2007-01-01

    Existing parallel MRI methods are limited by a fundamental trade-off in that suppressing noise introduces aliasing artifacts. Bayesian methods with an appropriately chosen image prior offer a promising alternative; however, previous methods with spatial priors assume that intensities vary smoothly over the entire image, resulting in blurred edges. Here we introduce an edge-preserving prior (EPP) that instead assumes that intensities are piecewise smooth, and propose a new approach to efficiently compute its Bayesian estimate. The estimation task is formulated as an optimization problem that requires a non-convex objective function to be minimized in a space with thousands of dimensions. As a result, traditional continuous minimization methods cannot be applied. This optimization task is closely related to some problems in the field of computer vision for which discrete optimization methods have been developed in the last few years. We adapt these algorithms, which are based on graph cuts, to address our optimization problem. The results of several parallel imaging experiments on brain and torso regions performed under challenging conditions with high acceleration factors are shown and compared with the results of conventional sensitivity encoding (SENSE) methods. An empirical analysis indicates that the proposed method visually improves overall quality compared to conventional methods. PMID:17195165

  17. Dispersive liquid-liquid microextraction based on solidification of floating organic drop for simultaneous separation/preconcentration of nickel, cobalt and copper prior to determination by electrothermal atomic absorption spectrometry

    Directory of Open Access Journals (Sweden)

    Mooud Amirkavei

    2013-01-01

    Full Text Available A dispersive liquid-liquid microextraction based on solidification of floating organic drop for simultaneous extraction of trace amounts of nickel, cobalt and copper followed by their determination with electrothermal atomic absorption spectrometry was developed. 300 µL of acetone and 1-undecanol was injected into an aqueous sample containing diethyldithiocarbamate complexes of metal ions. For a sample volume of 10 mL, enrichment factors of 277, 270 and 300 and detection limits of 1.2, 1.1 and 1 ng L-1 for nickel, cobalt and copper were obtained, respectively. The method was applied to the extraction and determination of these metals in different water samples.

  18. Dispersive liquid-liquid microextraction based on solidification of floating organic drop for simultaneous separation/preconcentration of nickel, cobalt and copper prior to determination by electrothermal atomic absorption spectrometry

    Directory of Open Access Journals (Sweden)

    Mooud Amirkavei

    2013-01-01

    Full Text Available A dispersive liquid-liquid microextraction based on solidification of floating organic drop for simultaneous extraction of trace amounts of nickel, cobalt and copper followed by their determination with electrothermal atomic absorption spectrometry was developed. 300 µL of acetone and 1-undecanol was injected into an aqueous sample containing diethyldithiocarbamate complexes of metal ions. For a sample volume of 10 mL, enrichment factors of 277, 270 and 300 and detection limits of 1.2, 1.1 and 1 ng L-1 for nickel, cobalt and copper were obtained, respectively. The method was applied to the extraction and determination of these metals in different water samples.

  19. Maximum entropy reconstruction of spin densities involving non uniform prior

    Energy Technology Data Exchange (ETDEWEB)

    Schweizer, J.; Ressouche, E. [DRFMC/SPSMS/MDN CEA-Grenoble (France); Papoular, R.J. [CEA-Saclay, Gif sur Yvette (France). Lab. Leon Brillouin; Tasset, F. [Inst. Laue Langevin, Grenoble (France); Zheludev, A.I. [Brookhaven National Lab., Upton, NY (United States). Physics Dept.

    1997-09-01

    Diffraction experiments give microscopic information on structures in crystals. A method which uses the concept of maximum of entropy (MaxEnt), appears to be a formidable improvement in the treatment of diffraction data. This method is based on a bayesian approach: among all the maps compatible with the experimental data, it selects that one which has the highest prior (intrinsic) probability. Considering that all the points of the map are equally probable, this probability (flat prior) is expressed via the Boltzman entropy of the distribution. This method has been used for the reconstruction of charge densities from X-ray data, for maps of nuclear densities from unpolarized neutron data as well as for distributions of spin density. The density maps obtained by this method, as compared to those resulting from the usual inverse Fourier transformation, are tremendously improved. In particular, any substantial deviation from the background is really contained in the data, as it costs entropy compared to a map that would ignore such features. However, in most of the cases, before the measurements are performed, some knowledge exists about the distribution which is investigated. It can range from the simple information of the type of scattering electrons to an elaborate theoretical model. In these cases, the uniform prior which considers all the different pixels as equally likely, is too weak a requirement and has to be replaced. In a rigorous bayesian analysis, Skilling has shown that prior knowledge can be encoded into the Maximum Entropy formalism through a model m({rvec r}), via a new definition for the entropy given in this paper. In the absence of any data, the maximum of the entropy functional is reached for {rho}({rvec r}) = m({rvec r}). Any substantial departure from the model, observed in the final map, is really contained in the data as, with the new definition, it costs entropy. This paper presents illustrations of model testing.

  20. Penalising Model Component Complexity: A Principled, Practical Approach to Constructing Priors

    KAUST Repository

    Simpson, Daniel

    2017-04-06

    In this paper, we introduce a new concept for constructing prior distributions. We exploit the natural nested structure inherent to many model components, which defines the model component to be a flexible extension of a base model. Proper priors are defined to penalise the complexity induced by deviating from the simpler base model and are formulated after the input of a user-defined scaling parameter for that model component, both in the univariate and the multivariate case. These priors are invariant to repa-rameterisations, have a natural connection to Jeffreys\\' priors, are designed to support Occam\\'s razor and seem to have excellent robustness properties, all which are highly desirable and allow us to use this approach to define default prior distributions. Through examples and theoretical results, we demonstrate the appropriateness of this approach and how it can be applied in various situations.

  1. Enhancement Algorithm for the Restoration of Dust Image Based on Dark-Channel Prior%基于暗原色先验的沙尘天气图像恢复算法研究

    Institute of Scientific and Technical Information of China (English)

    李海燕; 钟梦之

    2016-01-01

    Concerning the problem that image captured from dust weather has low contrast and details, based on the McCarney physical model and dark-channel piror theory ,an enhancement algorithm for the restoration of single dust image was proposed.The clear image could be recovered quickly.The experimental results show that the method can improve the quality and enhance the detail of the degraded image.%针对沙尘天气下图像质量下降的情况,在McCarney大气模型上,利用暗原色先验的规律和图像增强方法,提出一种快速、有效的单一图像恢复算法,并进行了仿真。实验结果表明,该算法能有效地恢复沙尘天气图像的清晰度,增强图像细节呈现。

  2. Care for women with prior preterm birth

    Science.gov (United States)

    Iams, Jay D.; Berghella, Vincenzo

    2013-01-01

    Women who have delivered an infant between 16 and 36 weeks’ gestation have an increased risk of preterm birth in subsequent pregnancies. The risk increases with more than 1 preterm birth and is inversely proportional to the gestational age of the previous preterm birth. African American women have rates of recurrent preterm birth that are nearly twice that of women of other backgrounds. An approximate risk of recurrent preterm birth can be estimated by a comprehensive reproductive history, with emphasis on maternal race, the number and gestational age of prior births, and the sequence of events preceding the index preterm birth. Interventions including smoking cessation, eradication of asymptomatic bacteriuria, progestational agents, and cervical cerclage can reduce the risk of recurrent preterm birth when employed appropriately. PMID:20417491

  3. Care for women with prior preterm birth.

    Science.gov (United States)

    Iams, Jay D; Berghella, Vincenzo

    2010-08-01

    Women who have delivered an infant between 16 and 36 weeks' gestation have an increased risk of preterm birth in subsequent pregnancies. The risk increases with more than 1 preterm birth and is inversely proportional to the gestational age of the previous preterm birth. African American women have rates of recurrent preterm birth that are nearly twice that of women of other backgrounds. An approximate risk of recurrent preterm birth can be estimated by a comprehensive reproductive history, with emphasis on maternal race, the number and gestational age of prior births, and the sequence of events preceding the index preterm birth. Interventions including smoking cessation, eradication of asymptomatic bacteriuria, progestational agents, and cervical cerclage can reduce the risk of recurrent preterm birth when employed appropriately. Copyright (c) 2010 Mosby, Inc. All rights reserved.

  4. Early medical abortion without prior ultrasound.

    Science.gov (United States)

    Raymond, Elizabeth G; Bracken, Hillary

    2015-09-01

    To explore the potential for using last menstrual period (LMP) rather than ultrasound to establish gestational age (GA) eligibility for medical abortion. We used the results of a recently published systematic review to identify studies with data on the number of abortion patients with GA more than 63 or 70 days by ultrasound but less than those or other specific limits by LMP. We analyzed data from these studies to estimate the proportion of women with GAs greater than 63 or 70 days by ultrasound in various subgroups of women defined by LMP. We found three studies with relevant data. One enrolled 4257 medical abortion patients of whom 4% had GAs of >70 days by ultrasound. Of the 2681 who were certain that their LMPs began no more than 56 days prior, only 16 (0.6%) were >70 days by ultrasound. In a second much smaller study of surgical abortion patients, of whom 19% were >70 days by ultrasound, 90 women were certain that their LMPs started more than 56 days prior, and of those, 7 (7.8%) had GAs of >70 days by ultrasound. In the third study, which included surgical abortion patients with a mean GA of 61 days, at least 12% of the 138 patients with LMPs 70 days by ultrasound. The possibility that access to medical abortion can be enhanced for selected women by omitting the requirement for a screening ultrasound is promising and should be further investigated. Gestational dating using LMP rather than ultrasound may be reasonable for selected patients before medical abortion. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Recursive estimation of prior probabilities using the mixture approach

    Science.gov (United States)

    Kazakos, D.

    1974-01-01

    The problem of estimating the prior probabilities q sub k of a mixture of known density functions f sub k(X), based on a sequence of N statistically independent observations is considered. It is shown that for very mild restrictions on f sub k(X), the maximum likelihood estimate of Q is asymptotically efficient. A recursive algorithm for estimating Q is proposed, analyzed, and optimized. For the M = 2 case, it is possible for the recursive algorithm to achieve the same performance with the maximum likelihood one. For M 2, slightly inferior performance is the price for having a recursive algorithm. However, the loss is computable and tolerable.

  6. The value of position-specific priors in motif discovery using MEME.

    Science.gov (United States)

    Bailey, Timothy L; Bodén, Mikael; Whitington, Tom; Machanick, Philip

    2010-04-09

    Position-specific priors have been shown to be a flexible and elegant way to extend the power of Gibbs sampler-based motif discovery algorithms. Information of many types-including sequence conservation, nucleosome positioning, and negative examples-can be converted into a prior over the location of motif sites, which then guides the sequence motif discovery algorithm. This approach has been shown to confer many of the benefits of conservation-based and discriminative motif discovery approaches on Gibbs sampler-based motif discovery methods, but has not previously been studied with methods based on expectation maximization (EM). We extend the popular EM-based MEME algorithm to utilize position-specific priors and demonstrate their effectiveness for discovering transcription factor (TF) motifs in yeast and mouse DNA sequences. Utilizing a discriminative, conservation-based prior dramatically improves MEME's ability to discover motifs in 156 yeast TF ChIP-chip datasets, more than doubling the number of datasets where it finds the correct motif. On these datasets, MEME using the prior has a higher success rate than eight other conservation-based motif discovery approaches. We also show that the same type of prior improves the accuracy of motifs discovered by MEME in mouse TF ChIP-seq data, and that the motifs tend to be of slightly higher quality those found by a Gibbs sampling algorithm using the same prior. We conclude that using position-specific priors can substantially increase the power of EM-based motif discovery algorithms such as MEME algorithm.

  7. The value of position-specific priors in motif discovery using MEME

    Directory of Open Access Journals (Sweden)

    Whitington Tom

    2010-04-01

    Full Text Available Abstract Background Position-specific priors have been shown to be a flexible and elegant way to extend the power of Gibbs sampler-based motif discovery algorithms. Information of many types–including sequence conservation, nucleosome positioning, and negative examples–can be converted into a prior over the location of motif sites, which then guides the sequence motif discovery algorithm. This approach has been shown to confer many of the benefits of conservation-based and discriminative motif discovery approaches on Gibbs sampler-based motif discovery methods, but has not previously been studied with methods based on expectation maximization (EM. Results We extend the popular EM-based MEME algorithm to utilize position-specific priors and demonstrate their effectiveness for discovering transcription factor (TF motifs in yeast and mouse DNA sequences. Utilizing a discriminative, conservation-based prior dramatically improves MEME's ability to discover motifs in 156 yeast TF ChIP-chip datasets, more than doubling the number of datasets where it finds the correct motif. On these datasets, MEME using the prior has a higher success rate than eight other conservation-based motif discovery approaches. We also show that the same type of prior improves the accuracy of motifs discovered by MEME in mouse TF ChIP-seq data, and that the motifs tend to be of slightly higher quality those found by a Gibbs sampling algorithm using the same prior. Conclusions We conclude that using position-specific priors can substantially increase the power of EM-based motif discovery algorithms such as MEME algorithm.

  8. 3D Scene Priors for Road Detection

    NARCIS (Netherlands)

    Alvarez, J.M.; Gevers, T.; Lopez, A.M.

    2010-01-01

    Vision-based road detection is important in different areas of computer vision such as autonomous driving, car collision warning and pedestrian crossing detection. However, current vision-based road detection methods are usually based on low-level features and they assume structured roads, road

  9. 3D Scene Priors for Road Detection

    NARCIS (Netherlands)

    J.M. Alvarez; T. Gevers; A.M. Lopez

    2010-01-01

    Vision-based road detection is important in different areas of computer vision such as autonomous driving, car collision warning and pedestrian crossing detection. However, current vision-based road detection methods are usually based on low-level features and they assume structured roads, road homo

  10. 3D Scene Priors for Road Detection

    NARCIS (Netherlands)

    Alvarez, J.M.; Gevers, T.; Lopez, A.M.

    2010-01-01

    Vision-based road detection is important in different areas of computer vision such as autonomous driving, car collision warning and pedestrian crossing detection. However, current vision-based road detection methods are usually based on low-level features and they assume structured roads, road homo

  11. Prior muscular exercise affects cycling pattern.

    Science.gov (United States)

    Bieuzen, F; Hausswirth, C; Couturier, A; Brisswalter, J

    2008-05-01

    The aim of this study was to investigate the effect of concentric or eccentric fatiguing exercise on cycling pattern. Eleven well trained cyclists completed three sessions of cycling (control cycling test [CTRL], cycling following concentric [CC] or eccentric [ECC] knee contractions) at a mean power of 276.8 +/- 26.6 Watts. Concentric and eccentric knee contractions were performed at a load corresponding to 80 % of one repetition maximum with both legs. Before and after CTRL, CC or ECC knee contractions and after cycling, a maximal voluntary contraction (MVC) test was performed. Cardiorespiratory, mechanical and electromyographic activity (EMG) of the rectus femoris, vastus lateralis and biceps femoris muscles were recorded during cycling. A significant decrease in MVC values was observed after CC and ECC exercises and after the cycling. ECC exercise induced a significant decrease in EMG root mean square during MVC and a decrease in pedal rate during cycling. EMG values of the three muscles were significantly higher during cycling exercise following CC exercise when compared to CTRL. The main finding of this study was that a prior ECC exercise induces a greater neuromuscular fatigue than a CC exercise, and changes in cycling pattern.

  12. Prior expectations facilitate metacognition for perceptual decision.

    Science.gov (United States)

    Sherman, M T; Seth, A K; Barrett, A B; Kanai, R

    2015-09-01

    The influential framework of 'predictive processing' suggests that prior probabilistic expectations influence, or even constitute, perceptual contents. This notion is evidenced by the facilitation of low-level perceptual processing by expectations. However, whether expectations can facilitate high-level components of perception remains unclear. We addressed this question by considering the influence of expectations on perceptual metacognition. To isolate the effects of expectation from those of attention we used a novel factorial design: expectation was manipulated by changing the probability that a Gabor target would be presented; attention was manipulated by instructing participants to perform or ignore a concurrent visual search task. We found that, independently of attention, metacognition improved when yes/no responses were congruent with expectations of target presence/absence. Results were modeled under a novel Bayesian signal detection theoretic framework which integrates bottom-up signal propagation with top-down influences, to provide a unified description of the mechanisms underlying perceptual decision and metacognition. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Human papilloma virus infection prior to coitarche.

    Science.gov (United States)

    Doerfler, Daniela; Bernhaus, Astrid; Kottmel, Andrea; Sam, Christine; Koelle, Dieter; Joura, Elmar A

    2009-05-01

    The aim of our study was to determine the prevalence and the natural course of anogenital human papilloma virus (HPV) infections in girls prior to coitarche attending an outpatient gynecological unit. Specimens were taken from the anogenital region of 114 unselected 4-15 year old girls who were referred consecutively for various gynecological problems. Four girls were excluded because of sexual abuse. Low-risk HPV-deoxyribonucleic acid (DNA) was detected in 4 girls (3.6%) and high-risk HPV DNA in 15 children (13.6%). Two girls testing positive for HPV DNA had clinical apparent warts. After 1 year, 2 children had persistent high-risk HPV DNA, and in 1 case we found a switch from high-risk to low-risk HPV DNA. Subclinical genital low- and high-risk HPV infections are common in girls without any history of sexual abuse or sexual activity. We found persistence of genital HPV infection in children, which could be a reservoir for HPV-associated diseases later in life.

  14. GRISOTTO: A greedy approach to improve combinatorial algorithms for motif discovery with prior knowledge

    Directory of Open Access Journals (Sweden)

    Oliveira Arlindo L

    2011-04-01

    Full Text Available Abstract Background Position-specific priors (PSP have been used with success to boost EM and Gibbs sampler-based motif discovery algorithms. PSP information has been computed from different sources, including orthologous conservation, DNA duplex stability, and nucleosome positioning. The use of prior information has not yet been used in the context of combinatorial algorithms. Moreover, priors have been used only independently, and the gain of combining priors from different sources has not yet been studied. Results We extend RISOTTO, a combinatorial algorithm for motif discovery, by post-processing its output with a greedy procedure that uses prior information. PSP's from different sources are combined into a scoring criterion that guides the greedy search procedure. The resulting method, called GRISOTTO, was evaluated over 156 yeast TF ChIP-chip sequence-sets commonly used to benchmark prior-based motif discovery algorithms. Results show that GRISOTTO is at least as accurate as other twelve state-of-the-art approaches for the same task, even without combining priors. Furthermore, by considering combined priors, GRISOTTO is considerably more accurate than the state-of-the-art approaches for the same task. We also show that PSP's improve GRISOTTO ability to retrieve motifs from mouse ChiP-seq data, indicating that the proposed algorithm can be applied to data from a different technology and for a higher eukaryote. Conclusions The conclusions of this work are twofold. First, post-processing the output of combinatorial algorithms by incorporating prior information leads to a very efficient and effective motif discovery method. Second, combining priors from different sources is even more beneficial than considering them separately.

  15. Evolution of Industry Knowledge in the Public Domain: Prior Art Searching for Software Patents

    Directory of Open Access Journals (Sweden)

    Jinseok Park

    2005-03-01

    Full Text Available Searching prior art is a key part of the patent application and examination processes. A comprehensive prior art search gives the inventor ideas as to how he can improve or circumvent existing technology by providing up to date knowledge on the state of the art. It also enables the patent applicant to minimise the likelihood of an objection from the patent office. This article explores the characteristics of prior art associated with software patents, dealing with difficulties in searching prior art due to the lack of resources, and considers public contribution to the formation of prior art databases. It addresses the evolution of electronic prior art in line with technological development, and discusses laws and practices in the EPO, USPTO, and the JPO in relation to the validity of prior art resources on the Internet. This article also investigates the main features of searching sources and tools in the three patent offices as well as non-patent literature databases. Based on the analysis of various searching databases, it provides some strategies of efficient prior art searching that should be considered for software-related inventions.

  16. Antibiotic consumption in children prior to diagnosis of asthma

    Directory of Open Access Journals (Sweden)

    FitzGerald Mark J

    2011-05-01

    Full Text Available ABSTRACT Background Asthma is difficult to diagnose in children and at times misdiagnosis of an infection can occur. However, little is known about the magnitude and patterns of antibiotic consumption in children with asthma relative to those without asthma. Methods Using population-based data, 128,872 children were identified with at least 6 years of follow-up. The adjusted rate-ratio (RR of antibiotics dispensed to asthmatic as compared to non-asthmatic children was determined. Results At age six, the RR of antibiotic consumption for asthmatics compared to non-asthmatics varied between, 1.66 to 2.32, depending on the year of asthma diagnosis. Of the 18,864 children with asthma at ages 2-8, 52% (n = 9,841 had antibiotics dispensed in the 6 months prior to their index date of asthma diagnosis. The RR of antibiotic consumption in the 1 month prior to asthma diagnosis compared to 5 months prior was 1.66 (95% CI 1.60-1.71. The RR was lower in males compared to females (1.58 vs 1.77, and lower in those who received antibiotics in the first year of life relative to those that did not (1.60 vs. 1.76. Conclusions There is higher antibiotic consumption in children with asthma compared to those without asthma. The pattern of antibiotic use suggests that diagnosis guidelines are difficult to follow in young children leading to misdiagnosis and over treatment with antibiotics.

  17. Improved single image dehazing using dark channel prior

    Institute of Scientific and Technical Information of China (English)

    Zhizhong Fu; Yanjing Yang; Chang Shu; Yuan Li; Honggang Wu; Jin Xu

    2015-01-01

    An improved single image dehazing method based on dark channel prior and wavelet transform is proposed. This pro-posed method employs wavelet transform and guided filter instead of the soft matting procedure to estimate and refine the depth map of haze images. Moreover, a contrast enhancement method based on just noticeable difference (JND) and quadratic function is adopted to enhance the contrast for the dehazed image, since the scene radiance is usual y not as bright as the atmospheric light, and the dehazed image looks dim. The experimental results show that the proposed approach can effectively enhance the haze ima-ge and is wel suitable for implementing on the surveil ance and obstacle detection systems.

  18. Scaling relations for galaxies prior to reionization

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Pengfei; Norman, Michael L.; Xu, Hao [CASS, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093 (United States); Wise, John H. [Center for Relativistic Astrophysics, School of Physics, Georgia Institute of Technology, 837 State Street, Atlanta, GA 30332 (United States); O' Shea, Brian W., E-mail: pec008@ucsd.edu, E-mail: mlnorman@ucsd.edu, E-mail: hxu@ucsd.edu, E-mail: jwise@gatech.edu, E-mail: oshea@msu.edu [Lyman Briggs College and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)

    2014-11-10

    The first galaxies in the universe are the building blocks of all observed galaxies. We present scaling relations for galaxies forming at redshifts z ≥ 15 when reionization is just beginning. We utilize the 'Rarepeak' cosmological radiation hydrodynamics simulation that captures the complete star formation history in over 3300 galaxies, starting with massive Population III stars that form in dark matter halos as small as ∼10{sup 6} M {sub ☉}. We make various correlations between the bulk halo quantities, such as virial, gas, and stellar masses and metallicities and their respective accretion rates, quantifying a variety of properties of the first galaxies up to halo masses of 10{sup 9} M {sub ☉}. Galaxy formation is not solely relegated to atomic cooling halos with virial temperatures greater than 10{sup 4} K, where we find a dichotomy in galaxy properties between halos above and below this critical mass scale. Halos below the atomic cooling limit have a stellar mass-halo mass relationship log M {sub *} ≅ 3.5 + 1.3log (M {sub vir}/10{sup 7} M {sub ☉}). We find a non-monotonic relationship between metallicity and halo mass for the smallest galaxies. Their initial star formation events enrich the interstellar medium and subsequent star formation to a median of 10{sup –2} Z {sub ☉} and 10{sup –1.5} Z {sub ☉}, respectively, in halos of total mass 10{sup 7} M {sub ☉}, which is then diluted by metal-poor inflows well beyond Population III pre-enrichment levels of 10{sup –3.5} Z {sub ☉}. The scaling relations presented here can be employed in models of reionization, galaxy formation, and chemical evolution in order to consider these galaxies forming prior to reionization.

  19. Directional interactions between current and prior saccades

    Directory of Open Access Journals (Sweden)

    Stephanie Anne Holland Jones

    2014-10-01

    Full Text Available One way to explore how prior sensory and motor events impact eye movements is to ask someone to look to targets located about a central point, returning gaze to the central point after each eye movement. Concerned about the contribution of this return to centre movement, Anderson et al. (2008 used a sequential saccade paradigm in which participants made a continuous series of saccades to peripheral targets that appeared to the left or right of the currently fixated location in a random sequence (the next eye movement began from the last target location. Examining the effects of previous saccades (n-x on current saccade latency (n, they found that saccadic reaction times (RT were reduced when the direction of the current saccade matched that of a preceding saccade (e.g. two left saccades, even when the two saccades in question were separated by multiple saccades in any direction. We examined if this pattern extends to conditions in which targets appear inside continuously marked locations that provide stable visual features (i.e. target ‘placeholders’ and when saccades are prompted by central arrows. Participants completed 3 conditions: peripheral targets (PT; continuous, sequential saccades to peripherally presented targets without placeholders; PT with placeholders; and centrally presented arrows (CA; left or right pointing arrows at the currently fixated location instructing participants to saccade to the left or right. We found reduced saccadic RT when the immediately preceding saccade (n-1 was in the same (vs. opposite direction in the PT without placeholders and CA conditions. This effect varied when considering the effect of the previous 2-5 (n-x saccades on current saccade latency (n. The effects of previous eye movements on current saccade latency may be determined by multiple, time-varying mechanisms related to sensory (i.e., retinotopic location, motor (i.e., saccade direction, and environmental (i.e., persistent visual objects

  20. Developing benchmarks for prior learning assessment. Part 1: Research.

    Science.gov (United States)

    Day, M

    The aim of the study was to develop and promote national benchmarks for those engaged in accreditation of prior learning (APL) termed 'prior learning assessment and recognition' (PLAR) assessment in Canada, in all sectors and communities. The study objectives were to gain practitioner consensus on the development of benchmarks for APL (PLAR) across Canada; produce a guide to support the implementation of national benchmarks; make recommendations for the promotion of the national benchmarks; and distribute the guide. The study also investigated the feasibility of developing a system to confirm the competence of APL (PLAR) practitioners, based on nationally agreed benchmarks for practice. A qualitative research strategy was developed, which used a benchmarking survey and focus groups as the primary research tools. These were applied to a purposive sample of APL practitioners (n = 91). The participants were identified through the use of an initial screening survey. Respondents indicated that in Canada, PLAR is used in a variety of ways to assist with individual and personal growth for human resource development, the preparation of professionals and the achievement of academic credit. The findings of the focus groups are summarised using a SWOT analysis The study identified that the main functions of the PLAR practitioners are to prepare individuals for assessment and conduct assessments. Although practitioners should be made aware of the potential conflicts in undertaking combined roles, they should be encouraged to develop confidence in both functions.

  1. Bayesian inference from count data using discrete uniform priors.

    Directory of Open Access Journals (Sweden)

    Federico Comoglio

    Full Text Available We consider a set of sample counts obtained by sampling arbitrary fractions of a finite volume containing an homogeneously dispersed population of identical objects. We report a Bayesian derivation of the posterior probability distribution of the population size using a binomial likelihood and non-conjugate, discrete uniform priors under sampling with or without replacement. Our derivation yields a computationally feasible formula that can prove useful in a variety of statistical problems involving absolute quantification under uncertainty. We implemented our algorithm in the R package dupiR and compared it with a previously proposed Bayesian method based on a Gamma prior. As a showcase, we demonstrate that our inference framework can be used to estimate bacterial survival curves from measurements characterized by extremely low or zero counts and rather high sampling fractions. All in all, we provide a versatile, general purpose algorithm to infer population sizes from count data, which can find application in a broad spectrum of biological and physical problems.

  2. On selecting a prior for the precision parameter of Dirichlet process mixture models

    Science.gov (United States)

    Dorazio, R.M.

    2009-01-01

    In hierarchical mixture models the Dirichlet process is used to specify latent patterns of heterogeneity, particularly when the distribution of latent parameters is thought to be clustered (multimodal). The parameters of a Dirichlet process include a precision parameter ?? and a base probability measure G0. In problems where ?? is unknown and must be estimated, inferences about the level of clustering can be sensitive to the choice of prior assumed for ??. In this paper an approach is developed for computing a prior for the precision parameter ?? that can be used in the presence or absence of prior information about the level of clustering. This approach is illustrated in an analysis of counts of stream fishes. The results of this fully Bayesian analysis are compared with an empirical Bayes analysis of the same data and with a Bayesian analysis based on an alternative commonly used prior.

  3. Assessors' approaches to portfolio assessment in Assessment of Prior Learning procedures

    OpenAIRE

    Sluijsmans, Dominique; Joosten-ten Brinke, Desirée; Jochems, W.

    2010-01-01

    In an effort to gain better understanding of the assessment of prior informal and non-formal learning, this article explores assessors’ approaches to portfolio assessment. Through this portfolio assessment, candidates had requested exemptions from specific courses within an educational programme or admission to the programme based on their prior learning. The assessors judged the portfolios according to set rating criteria, and subsequently discussed their approaches. Their decision-making pr...

  4. Hierarchical image segmentation for learning object priors

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, Lakshman [Los Alamos National Laboratory; Yang, Xingwei [TEMPLE UNIV.; Latecki, Longin J [TEMPLE UNIV.; Li, Nan [TEMPLE UNIV.

    2010-11-10

    The proposed segmentation approach naturally combines experience based and image based information. The experience based information is obtained by training a classifier for each object class. For a given test image, the result of each classifier is represented as a probability map. The final segmentation is obtained with a hierarchial image segmentation algorithm that considers both the probability maps and the image features such as color and edge strength. We also utilize image region hierarchy to obtain not only local but also semi-global features as input to the classifiers. Moreover, to get robust probability maps, we take into account the region context information by averaging the probability maps over different levels of the hierarchical segmentation algorithm. The obtained segmentation results are superior to the state-of-the-art supervised image segmentation algorithms.

  5. Diagnostics Tools Identify Faults Prior to Failure

    Science.gov (United States)

    2013-01-01

    Through the SBIR program, Rochester, New York-based Impact Technologies LLC collaborated with Ames Research Center to commercialize the Center s Hybrid Diagnostic Engine, or HyDE, software. The fault detecting program is now incorporated into a software suite that identifies potential faults early in the design phase of systems ranging from printers to vehicles and robots, saving time and money.

  6. The Impact of Prior Heterosexual Experiences on Homosexuality in Women

    Directory of Open Access Journals (Sweden)

    Marissa A. Harrison

    2008-04-01

    Full Text Available An abundance of unwanted sexual opportunities perpetrated by insensitive, physically and sexually abusive men may be a factor in the expression of homosexuality in some women. In the present study, we examined self-reports of dating histories, sexual experiences, and physical and sexual abuse among lesbians and heterosexual women. Lesbians with prior heterosexual experience reported more severe and more frequent physical abuse by men. Lesbians also reported more instances of forced, unwanted sexual contact perpetrated by men, and this sexual abuse occurred at a significantly earlier age. These data show that adverse experiences with the opposite sex are more common in lesbians than heterosexual women, and therefore negative heterosexual experiences may be a factor in the expression of a same-sex sexual orientation in women. We propose an evolutionary psychological interpretation of this phenomenon based on the cardinally different mating strategies of women and men that have evolved for maximizing the likelihood of reproduction.

  7. Bayesian Model Comparison With the g-Prior

    DEFF Research Database (Denmark)

    Nielsen, Jesper Kjær; Christensen, Mads Græsbøll; Cemgil, Ali Taylan

    2014-01-01

    Model comparison and selection is an important problem in many model-based signal processing applications. Often, very simple information criteria such as the Akaike information criterion or the Bayesian information criterion are used despite their shortcomings. Compared to these methods, Djuric......’s asymptotic MAP rule was an improvement, and in this paper we extend the work by Djuric in several ways. Specifically, we consider the elicitation of proper prior distributions, treat the case of real- and complex-valued data simultaneously in a Bayesian framework similar to that considered by Djuric......, and develop new model selection rules for a regression model containing both linear and non-linear parameters. Moreover, we use this framework to give a new interpretation of the popular information criteria and relate their performance to the signal-to-noise ratio of the data. By use of simulations, we also...

  8. A Comparison of Inverse-Wishart Prior Specifications for Covariance Matrices in Multilevel Autoregressive Models.

    Science.gov (United States)

    Schuurman, N K; Grasman, R P P P; Hamaker, E L

    2016-01-01

    Multilevel autoregressive models are especially suited for modeling between-person differences in within-person processes. Fitting these models with Bayesian techniques requires the specification of prior distributions for all parameters. Often it is desirable to specify prior distributions that have negligible effects on the resulting parameter estimates. However, the conjugate prior distribution for covariance matrices-the Inverse-Wishart distribution-tends to be informative when variances are close to zero. This is problematic for multilevel autoregressive models, because autoregressive parameters are usually small for each individual, so that the variance of these parameters will be small. We performed a simulation study to compare the performance of three Inverse-Wishart prior specifications suggested in the literature, when one or more variances for the random effects in the multilevel autoregressive model are small. Our results show that the prior specification that uses plug-in ML estimates of the variances performs best. We advise to always include a sensitivity analysis for the prior specification for covariance matrices of random parameters, especially in autoregressive models, and to include a data-based prior specification in this analysis. We illustrate such an analysis by means of an empirical application on repeated measures data on worrying and positive affect.

  9. Selected aspects of prior and likelihood information for a Bayesian classifier in a road safety analysis.

    Science.gov (United States)

    Nowakowska, Marzena

    2017-04-01

    The development of the Bayesian logistic regression model classifying the road accident severity is discussed. The already exploited informative priors (method of moments, maximum likelihood estimation, and two-stage Bayesian updating), along with the original idea of a Boot prior proposal, are investigated when no expert opinion has been available. In addition, two possible approaches to updating the priors, in the form of unbalanced and balanced training data sets, are presented. The obtained logistic Bayesian models are assessed on the basis of a deviance information criterion (DIC), highest probability density (HPD) intervals, and coefficients of variation estimated for the model parameters. The verification of the model accuracy has been based on sensitivity, specificity and the harmonic mean of sensitivity and specificity, all calculated from a test data set. The models obtained from the balanced training data set have a better classification quality than the ones obtained from the unbalanced training data set. The two-stage Bayesian updating prior model and the Boot prior model, both identified with the use of the balanced training data set, outperform the non-informative, method of moments, and maximum likelihood estimation prior models. It is important to note that one should be careful when interpreting the parameters since different priors can lead to different models.

  10. Prior Information in Inverse Boundary Problems

    DEFF Research Database (Denmark)

    Garde, Henrik

    This thesis gives a threefold perspective on the inverse problem of inclusion detection in electrical impedance tomography: depth dependence, monotonicitybased reconstruction, and sparsity-based reconstruction. The depth dependence is given in terms of explicit bounds on the datum norm, which shows...... be regularized against noise with a uniform regularization parameter, and that the method can be generalized to discrete electrode models. We give examples in 2D and 3D with noisy simulated data as well as real measurements, and give a comparison of reconstructions based on a non-linear and a linear formulation...... of the reconstruction. Numerical examples are given in both 2D and 3D for partial data using noisy simulated data as well as real measurements....

  11. Comparison of no-prior and soft-prior regularization in biomedical microwave imaging

    Directory of Open Access Journals (Sweden)

    Amir H Golnabi

    2011-01-01

    Full Text Available Microwave imaging for medical applications is attractive because the range of dielectric properties of different soft tissues can be substantial. Breast cancer detection and monitoring of treatment response are areas where this technology could be important because of the contrast between normal and malignant tissue. Unfortunately, the technique is unable to achieve the high spatial resolution at depth in tissue which is available from other conventional modalities such as x-ray computed tomography (CT or magnetic resonance imaging (MRI. We have incorporated a soft-prior regularization strategy within our microwave reconstruction algorithm and compared it with the images obtained with traditional no-prior (Levenberg-Marquardt regularization. Initial simulation and phantom results show a significant improvement of the recovered electrical properties. Specifically, errors in the microwave property estimates were improved by as much as 95%. The effects of a false-inclusion region were also evaluated and the results show that a small residual property bias of 6% in permittivity and 15% in conductivity can occur that does not otherwise degrade the property recovery accuracy of inclusions that actually exist. The work sets the stage for integrating microwave imaging with MR for improved resolution and functional imaging of the breast in the future.

  12. Graduate global public health education: activities and outcomes in relation to student prior experience.

    Science.gov (United States)

    Jackson, Suzanne F; Cole, Donald C

    2013-01-31

    The Dalla Lana School of Public Health uses an "add-on" or concentration model of global health education. Records of masters' graduate cohorts across five disciplinary fields from 2006 to 2009 were classified as to prior experience at application and completion of global health concentration requirements. Alumni from the first two cohorts (2006-08 and 2007-09) were interviewed using a semi-structured interview guide. Prior experience was not linked consistently with the number of elective courses, location of practica or completion of requirements. Successful completion of the global health requirements depended more on the student's base disciplinary program. Interviewed alumni with medium prior experience reported greater satisfaction with the concentration. Alumni with lower prior experience wanted more courses and support with practica. The pros and cons of a concentration model of global public health graduate education are discussed.

  13. Graph cuts with invariant object-interaction priors: application to intervertebral disc segmentation.

    Science.gov (United States)

    Ben Ayed, Ismail; Punithakumar, Kumaradevan; Garvin, Gregory; Romano, Walter; Li, Shuo

    2011-01-01

    This study investigates novel object-interaction priors for graph cut image segmentation with application to intervertebral disc delineation in magnetic resonance (MR) lumbar spine images. The algorithm optimizes an original cost function which constrains the solution with learned prior knowledge about the geometric interactions between different objects in the image. Based on a global measure of similarity between distributions, the proposed priors are intrinsically invariant with respect to translation and rotation. We further introduce a scale variable from which we derive an original fixed-point equation (FPE), thereby achieving scale-invariance with only few fast computations. The proposed priors relax the need of costly pose estimation (or registration) procedures and large training sets (we used a single subject for training), and can tolerate shape deformations, unlike template-based priors. Our formulation leads to an NP-hard problem which does not afford a form directly amenable to graph cut optimization. We proceeded to a relaxation of the problem via an auxiliary function, thereby obtaining a nearly real-time solution with few graph cuts. Quantitative evaluations over 60 intervertebral discs acquired from 10 subjects demonstrated that the proposed algorithm yields a high correlation with independent manual segmentations by an expert. We further demonstrate experimentally the invariance of the proposed geometric attributes. This supports the fact that a single subject is sufficient for training our algorithm, and confirms the relevance of the proposed priors to disc segmentation.

  14. Assessing Acceptance of Adaptive Educational Hypermedia Systems: Prior Knowledge vs Cognitive Styles

    Directory of Open Access Journals (Sweden)

    Freddy Mampadi

    2012-07-01

    Full Text Available Perceived usefulness and ease of use have proved to be key determinants of the acceptance and usage of e-learning systems. On the contrary, little is known about students perceptions in Adaptive Educational Hypermedia Systems (AEHS. In this paper, the Technology Acceptance Model (TAM was utilized to investigate university students attitudes towards AEHSs. The goal of the study was to investigate whether students perceptions towards AEHS that adapts basing on cognitive styles were comparable to perceptions of students using AEHS that adapts basing on prior knowledge. This is part of a project to determine how prior knowledge and cognitive styles could be combined in AEHS to maximize learning and comprehension of educational materials. To this end, the study presented in this paper developed two AEHSs, one tailored to students prior knowledge while the other to their cognitive styles with emphasis on Holist-Serialist dimension. Comparative effects of using the two systems employing perceptions and attitudes as a measure were then investigated. In total, 104 students participated in the study, 60 students using the prior knowledge version while 44 participated on the cognitive styles version. The findings indicate that students using the cognitive styles version had more positive attitudes and perceptions towards their version than those who used the prior knowledge version. The implications of these results for the design of effective AEHSs combining prior knowledge and cognitive styles are discussed.

  15. Modeling the effects of prior infection on vaccine efficacy

    Energy Technology Data Exchange (ETDEWEB)

    Smith, D.J.; Forrest, S.; Ackley, D.H. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Computer Science; Perelson, A.S. [Los Alamos National Lab., NM (United States)

    1997-11-01

    We performed computer simulations to study the effects of prior infection on vaccine efficacy. We injected three antigens sequentially. The first antigen, designated the prior, represented a prior infection or vaccination. The second antigen, the vaccine, represented a single component of the trivalent influenza vaccine. The third antigen, the epidemic, represented challenge by an epidemic strain. For a fixed vaccine to epidemic strain cross-reactivities to the vaccine and to the epidemic strains. We found that, for many cross-reactivities, vaccination, when it had been preceded by a prior infection, provided more protection than vaccination alone. However, at some cross-reactivities, the prior infection reduced protection by clearing the vaccine before it had the chance to produce protective memory. The cross-reactivities between the prior, vaccine and epidemic strains played a major role in determining vaccine efficacy. This work has applications to understanding vaccination against viruses such as influenza that are continually mutating.

  16. Sukhareva--Prior to Asperger and Kanner.

    Science.gov (United States)

    Manouilenko, Irina; Bejerot, Susanne

    2015-08-01

    As early as 1926, the Kiev-based child psychiatrist Grunya Efimovna Sukhareva (Груня Ефимовна Сухарева) (1891-1981) published a detailed description of autistic traits in a number of children in a scientific German psychiatry and neurology journal. She initially used the term "schizoid (eccentric) psychopathy" but later replaced it with "autistic (pathological avoidant) psychopathy" to describe the clinical picture of autism. Her original article was available almost two decades before the case reports of Asperger and Kanner; nevertheless, Sukhareva's pioneer work has been greatly overlooked. Here we present her description of autistic psychopathy in relation to the DSM-5 criteria of today.

  17. Bayesian estimation of generalized exponential distribution under noninformative priors

    Science.gov (United States)

    Moala, Fernando Antonio; Achcar, Jorge Alberto; Tomazella, Vera Lúcia Damasceno

    2012-10-01

    The generalized exponential distribution, proposed by Gupta and Kundu (1999), is a good alternative to standard lifetime distributions as exponential, Weibull or gamma. Several authors have considered the problem of Bayesian estimation of the parameters of generalized exponential distribution, assuming independent gamma priors and other informative priors. In this paper, we consider a Bayesian analysis of the generalized exponential distribution by assuming the conventional noninformative prior distributions, as Jeffreys and reference prior, to estimate the parameters. These priors are compared with independent gamma priors for both parameters. The comparison is carried out by examining the frequentist coverage probabilities of Bayesian credible intervals. We shown that maximal data information prior implies in an improper posterior distribution for the parameters of a generalized exponential distribution. It is also shown that the choice of a parameter of interest is very important for the reference prior. The different choices lead to different reference priors in this case. Numerical inference is illustrated for the parameters by considering data set of different sizes and using MCMC (Markov Chain Monte Carlo) methods.

  18. Prior knowledge in recalling arguments in bioethical dilemmas

    Directory of Open Access Journals (Sweden)

    Hiemke Katharina Schmidt

    2015-09-01

    Full Text Available Prior knowledge is known to facilitate learning new information. Normally in studies confirming this outcome the relationship between prior knowledge and the topic to be learned is obvious: the information to be acquired is part of the domain or topic to which the prior knowledge belongs. This raises the question as to whether prior knowledge of various domains facilitates recalling information. In this study 79 eleventh-grade students completed a questionnaire on their prior knowledge of seven different domains related to the bioethical dilemma of prenatal diagnostics. The students read a text containing arguments for and arguments against prenatal diagnostics. After one week and again 12 weeks later they were asked to write down all the arguments they remembered. Prior knowledge helped them recall the arguments one week (r = .350 and 12 weeks (r = .316 later. Prior knowledge of three of the seven domains significantly helped them recall the arguments one week later (correlations between r = .194 to r = .394. Partial correlations with interest as a control item revealed that interest did not explain the relationship between prior knowledge and recall. Prior knowledge of different domains jointly supports the recall of arguments related to bioethical topics.

  19. Chromosomal differences between acute nonlymphocytic leukemia in patients with prior solid tumors and prior hematologic malignancies. A study of 14 cases with prior breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Mamuris, Z.; Dumont, J.; Dutrillaux, B.; Aurias, A. (Institut Curie, Paris (France))

    1989-10-01

    A cytogenetic study of 14 patients with secondary acute nonlymphocytic leukemia (S-ANLL) with prior treatment for breast cancer is reported. The chromosomes recurrently involved in numerical or structural anomalies are chromosomes 7, 5, 17, and 11, in decreasing order of frequency. The distribution of the anomalies detected in this sample of patients is similar to that observed in published cases with prior breast or other solid tumors, though anomalies of chromosome 11 were not pointed out, but it significantly differs from that of the S-ANLL with prior hematologic malignancies. This difference is principally due to a higher involvement of chromosome 7 in patients with prior hematologic malignancies and of chromosomes 11 and 17 in patients with prior solid tumors. A genetic determinism involving abnormal recessive alleles located on chromosomes 5, 7, 11, and 17 uncovered by deletions of the normal homologs may be a cause of S-ANLL. The difference between patients with prior hematologic malignancies or solid tumors may be explained by different constitutional mutations of recessive genes in the two groups of patients.

  20. 基于创业团队先前经验的新技术企业市场进入战略选择研究%Market Entry Strategy Selection of New Technology Venture Based on Prior Experiences of Entrepreneurial Team

    Institute of Scientific and Technical Information of China (English)

    田莉; 张玉利

    2012-01-01

    基于社会认知和战略选择等理论知识,探讨创业团队先前经验构成特征与进入战略创新性的逻辑关系,并探索技术独享性和环境宽松性对团队决策的影响.基于随机抽样的问卷调研方法,利用150份新技术企业样本进行实证分析.研究结果表明,新技术企业初始战略来源于创业团队基于先前经验而达成的集体认知决策,技术导向型团队倾向于通过产品或服务的创新进入市场,而市场导向型的团队则会竭力从交易结构的创新入手,兼顾技术和市场导向的团队,虽然拥有多元化的认知模式,却没能迸发出应有的创造力.技术独享性在创业团队经验构成与进入战略创新性之间发挥正向调节作用,但没有改变团队成员固有认知模式;环境宽松性改变了创业团队在选择市场进入战略时的关注点,当环境较为宽松时,技术导向型和市场导向型的创业团队都呈现出对产品或服务创新的忽视,而加大了在交易结构上谋求创新的力度.%Based on social cognition theory and strategic choice theory, the study demonstrates the relationship between structure of prior experiences and innovation of entry strategy and explores the effect of technology appropriability and environment munificence on decision-making. 150 copies of questionnaires were used for empirical examination. It finds that founding strategy originates from collective cognitive decision based on entrepreneurial teams' prior experiences. Specifically, the technology-oriented teams tend to enter the market by innovative products or services, while the market-oriented teams prefer transaction structure innovation. The heterogeneous team with both technology and market orientation failed to innovate on entry strategy in spite of themultiple cognitive mode. Meanwhile, technology appropriability moderates the relationship between structure of prior experiences and innovation of entry strategy, but could

  1. Andrographolide suppresses thymic stromal lymphopoietin in phorbol myristate acetate/calcium ionophore A23187-activated mast cells and 2,4-dinitrofluorobenzene-induced atopic dermatitis-like mice model

    Directory of Open Access Journals (Sweden)

    Li CX

    2016-02-01

    Full Text Available Chun-xiao Li,* Hua-guo Li,* Hui Zhang,* Ru-hong Cheng, Ming Li, Jian-ying Liang, Yan Gu, Bo Ling, Zhi-rong Yao, Hong Yu Department of Dermatology, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People’s Republic of China *These authors contributed equally to this work Background: Atopic dermatitis (AD is one of the most common inflammatory cutaneous diseases. Thymic stromal lymphopoietin (TSLP has been demonstrated to be an important immunologic factor in the pathogenesis of AD. The production of TSLP can be induced by a high level of intracellular calcium concentration and activation of the receptor-interacting protein 2/caspase-1/NF-κB pathway. Andrographolide (ANDRO, a natural bicyclic diterpenoid lactone, has been found to exert anti-inflammatory effects in gastrointestinal inflammatory disorders through suppressing the NF-κB pathway. Objective: To explore the effect of ANDRO on the production of TSLP in human mast cells and AD mice model. Methods: We utilized enzyme-linked immunosorbent assay, real-time reverse transcription polymerase chain reaction analysis, Western blot analysis, and immunofluorescence staining assay to investigate the effects of ANDRO on AD. Results: ANDRO ameliorated the increase in the intracellular calcium, protein, and messenger RNA levels of TSLP induced by phorbol myristate acetate/calcium ionophore A23187, through the blocking of the receptor-interacting protein 2/caspase-1/NF-κB pathway in human mast cell line 1 cells. ANDRO, via oral or local administration, also attenuated clinical symptoms in 2,4-dinitrofluorobenzene-induced AD mice model and suppressed the levels of TSLP in lesional skin. Conclusion: Taken together, ANDRO may be a potential therapeutic agent for AD through suppressing the expression of TSLP. Keywords: atopic dermatitis, thymic stromal lymphopoietin, andrographolide, human mast cell

  2. A Novel Sensor for Monitoring of Iron(III Ions Based on Porphyrins

    Directory of Open Access Journals (Sweden)

    Mayte Gil-Agusti

    2012-06-01

    Full Text Available Three A3B porphyrins with mixed carboxy-, phenoxy-, pyridyl- and dimethoxy-substituent functionalization on the meso-phenyl groups were obtained by multicomponent synthesis, fully characterized and used as ionophores for preparing PVC-based membrane sensors selective to iron(III. The membranes have an ionophore:PVC:plasticizer composition ratio of 1:33:66. Sodium tetraphenylborate was used as additive (20 mol% relative to ionophore. The performance characteristics (linear concentration range, slope and selectivity of the sensors were investigated. The best results were obtained for the membrane based on 5-(4-carboxyphenyl-10,15,20-tris(4-phenoxyphenyl-porphyrin plasticized with bis(2-ethylhexylsebacate, in a linear range from 1 × 10−7–1 × 10−1 M with a slope of 21.6 mV/decade. The electrode showed high selectivity with respect to alkaline and heavy metal ions and a response time of 20 s. The influence of pH on the sensor response was studied. The sensor was used for a period of six weeks and the utility has been tested for the quantitative determination of Fe(III in recovered solutions from spent lithium ion batteries and for the quantitative determination of Fe(III in tap water samples.

  3. A novel sensor for monitoring of iron(III) ions based on porphyrins.

    Science.gov (United States)

    Vlascici, Dana; Fagadar-Cosma, Eugenia; Popa, Iuliana; Chiriac, Vlad; Gil-Agusti, Mayte

    2012-01-01

    Three A(3)B porphyrins with mixed carboxy-, phenoxy-, pyridyl-, and dimethoxy-substituent functionalization on the meso-phenyl groups were obtained by multicomponent synthesis, fully characterized and used as ionophores for preparing PVC-based membrane sensors selective to iron(III). The membranes have an ionophore:PVC:plasticizer composition ratio of 1:33:66. Sodium tetraphenylborate was used as additive (20 mol% relative to ionophore). The performance characteristics (linear concentration range, slope and selectivity) of the sensors were investigated. The best results were obtained for the membrane based on 5-(4-carboxyphenyl)-10,15,20-tris(4-phenoxyphenyl)-porphyrin plasticized with bis(2-ethylhexyl)sebacate, in a linear range from 1 × 10(-7)-1 × 10(-1) M with a slope of 21.6 mV/decade. The electrode showed high selectivity with respect to alkaline and heavy metal ions and a response time of 20 s. The influence of pH on the sensor response was studied. The sensor was used for a period of six weeks and the utility has been tested for the quantitative determination of Fe(III) in recovered solutions from spent lithium ion batteries and for the quantitative determination of Fe(III) in tap water samples.

  4. A Novel Sensor for Monitoring of Iron(III) Ions Based on Porphyrins

    Science.gov (United States)

    Vlascici, Dana; Fagadar-Cosma, Eugenia; Popa, Iuliana; Chiriac, Vlad; Gil-Agusti, Mayte

    2012-01-01

    Three A3B porphyrins with mixed carboxy-, phenoxy-, pyridyl-, and dimethoxy-substituent functionalization on the meso-phenyl groups were obtained by multicomponent synthesis, fully characterized and used as ionophores for preparing PVC-based membrane sensors selective to iron(III). The membranes have an ionophore:PVC:plasticizer composition ratio of 1:33:66. Sodium tetraphenylborate was used as additive (20 mol% relative to ionophore). The performance characteristics (linear concentration range, slope and selectivity) of the sensors were investigated. The best results were obtained for the membrane based on 5-(4-carboxyphenyl)-10,15,20-tris(4-phenoxyphenyl)-porphyrin plasticized with bis(2-ethylhexyl)sebacate, in a linear range from 1 × 10−7–1 × 10−1 M with a slope of 21.6 mV/decade. The electrode showed high selectivity with respect to alkaline and heavy metal ions and a response time of 20 s. The influence of pH on the sensor response was studied. The sensor was used for a period of six weeks and the utility has been tested for the quantitative determination of Fe(III) in recovered solutions from spent lithium ion batteries and for the quantitative determination of Fe(III) in tap water samples. PMID:22969395

  5. Compressive Sensing With Prior Support Quality Information and Application to Massive MIMO Channel Estimation With Temporal Correlation

    Science.gov (United States)

    Rao, Xiongbin; Lau, Vincent K. N.

    2015-09-01

    In this paper, we consider the problem of compressive sensing (CS) recovery with a prior support and the prior support quality information available. Different from classical works which exploit prior support blindly, we shall propose novel CS recovery algorithms to exploit the prior support adaptively based on the quality information. We analyze the distortion bound of the recovered signal from the proposed algorithm and we show that a better quality prior support can lead to better CS recovery performance. We also show that the proposed algorithm would converge in $\\mathcal{O}\\left(\\log\\mbox{SNR}\\right)$ steps. To tolerate possible model mismatch, we further propose some robustness designs to combat incorrect prior support quality information. Finally, we apply the proposed framework to sparse channel estimation in massive MIMO systems with temporal correlation to further reduce the required pilot training overhead.

  6. Brain Tumor Segmentation Using a Generative Model with an RBM Prior on Tumor Shape

    DEFF Research Database (Denmark)

    Agn, Mikael; Puonti, Oula; Rosenschöld, Per Munck af;

    2016-01-01

    In this paper, we present a fully automated generative method for brain tumor segmentation in multi-modal magnetic resonance images. The method is based on the type of generative model often used for segmenting healthy brain tissues, where tissues are modeled by Gaussian mixture models combined...... with a spatial atlas-based tissue prior. We extend this basic model with a tumor prior, which uses convolutional restricted Boltzmann machines (cRBMs) to model the shape of both tumor core and complete tumor, which includes edema and core. The cRBMs are trained on expert segmentations of training images, without...

  7. Design Hybrid Methods for Encoding Prior Knowledge in Feedforward Network with Application in Chemical Engineering

    Institute of Scientific and Technical Information of China (English)

    CHENChongwei; CHENDezhao

    2002-01-01

    Three-layer feedforward networks have been widely used in modeling chemical engineering processes and prior-knowledge-based methods have been introduced to improve their performances.In this paper,we propose the methodology of designing better prior-knowledge-based hybrid methods by combining the existing ones. Then according to this methodology,two hybrid methods,interpolation-optimization (IO) method and interpolation penalty-function (IPF) method,are designed as examples.Finally,both methods are applied to modeling two cases in chemical engineering to investigate their effectiveness.Simulation results show that the performances of the hybrid methods are better than those of their parents.

  8. Elapsed decision time affects the weighting of prior probability in a perceptual decision task

    Science.gov (United States)

    Hanks, Timothy D.; Mazurek, Mark E.; Kiani, Roozbeh; Hopp, Elizabeth; Shadlen, Michael N.

    2012-01-01

    Decisions are often based on a combination of new evidence with prior knowledge of the probable best choice. Optimal combination requires knowledge about the reliability of evidence, but in many realistic situations, this is unknown. Here we propose and test a novel theory: the brain exploits elapsed time during decision formation to combine sensory evidence with prior probability. Elapsed time is useful because (i) decisions that linger tend to arise from less reliable evidence, and (ii) the expected accuracy at a given decision time depends on the reliability of the evidence gathered up to that point. These regularities allow the brain to combine prior information with sensory evidence by weighting the latter in accordance with reliability. To test this theory, we manipulated the prior probability of the rewarded choice while subjects performed a reaction-time discrimination of motion direction using a range of stimulus reliabilities that varied from trial to trial. The theory explains the effect of prior probability on choice and reaction time over a wide range of stimulus strengths. We found that prior probability was incorporated into the decision process as a dynamic bias signal that increases as a function of decision time. This bias signal depends on the speed-accuracy setting of human subjects, and it is reflected in the firing rates of neurons in the lateral intraparietal cortex (LIP) of rhesus monkeys performing this task. PMID:21525274

  9. High School Students' Publication Rights and Prior Restraint.

    Science.gov (United States)

    Huffman, John L.; Trauth, Denise M.

    1981-01-01

    Federal court decisions on high school students' publication rights in the Second, Fourth, Fifth, and Seventh Circuits reveal substantial disagreement about school officials' power of prior restraint over student publications. The courts' opinions range from approval of broad powers of prior restraint to denial of any power. (Author/RW)

  10. 25 CFR 13.13 - Technical assistance prior to petitioning.

    Science.gov (United States)

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Technical assistance prior to petitioning. 13.13 Section... OF JURISDICTION OVER CHILD CUSTODY PROCEEDINGS Reassumption § 13.13 Technical assistance prior to... matters, Bureau agency and Area Offices shall provide technical assistance and make available any...

  11. Prior Abdominal Surgery Jeopardizes Quality of Resection in Colorectal Cancer

    NARCIS (Netherlands)

    Stommel, M.W.J.; Wilt, J.H.W. de; Broek, R.P.G ten; Strik, C.; Rovers, M.M.; Goor, H. van

    2016-01-01

    BACKGROUND: Prior abdominal surgery increases complexity of abdominal operations. Effort to prevent injury during adhesiolysis might result in less extensive bowel resection in colorectal cancer surgery. The aim of this study was to evaluate the effect of prior abdominal surgery on the outcome of

  12. Effects of Prior Knowledge on Memory: Implications for Education

    Science.gov (United States)

    Shing, Yee Lee; Brod, Garvin

    2016-01-01

    The encoding, consolidation, and retrieval of events and facts form the basis for acquiring new skills and knowledge. Prior knowledge can enhance those memory processes considerably and thus foster knowledge acquisition. But prior knowledge can also hinder knowledge acquisition, in particular when the to-be-learned information is inconsistent with…

  13. Source-specific Informative Prior for i-Vector Extraction

    DEFF Research Database (Denmark)

    Shepstone, Sven Ewan; Lee, Kong Aik; Li, Haizhou

    2015-01-01

    -informative, since for homogeneous datasets there is no gain in generality in using an informative prior. This work shows that extracting i-vectors for a heterogeneous dataset, containing speech samples recorded from multiple sources, using informative priors instead is applicable, and leads to favorable results...

  14. 18 CFR 415.51 - Prior non-conforming structures.

    Science.gov (United States)

    2010-04-01

    ... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Prior non-conforming... ADMINISTRATIVE MANUAL BASIN REGULATIONS-FLOOD PLAIN REGULATIONS Enforcement § 415.51 Prior non-conforming... this part): (a) A non-conforming structure in the floodway may not be expanded, except that it may...

  15. EEG Sequence Imaging: A Markov Prior for the Variational Garrote

    DEFF Research Database (Denmark)

    Hansen, Sofie Therese; Hansen, Lars Kai

    2013-01-01

    We propose the following generalization of the Variational Garrote for sequential EEG imaging: A Markov prior to promote sparse, but temporally smooth source dynamics. We derive a set of modied Variational Garrote updates and analyze the role of the prior's hyperparameters. An experimental evalua...

  16. 7 CFR 1412.74 - Prior enrollment in DCP.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Prior enrollment in DCP. 1412.74 Section 1412.74... (ACRE) Program § 1412.74 Prior enrollment in DCP. (a) If a farm was enrolled in a DCP contract according... request to have the DCP contract withdrawn for that crop year. To participate in an annual ACRE...

  17. Portfolios for Prior Learning Assessment: Caught between Diversity and Standardization

    Science.gov (United States)

    Sweygers, Annelies; Soetewey, Kim; Meeus, Wil; Struyf, Elke; Pieters, Bert

    2009-01-01

    In recent years, procedures have been established in Flanders for "Prior Learning Assessment" (PLA) outside the formal learning circuit, of which the portfolio is a regular component. In order to maximize the possibilities of acknowledgement of prior learning assessment, the Flemish government is looking for a set of common criteria and…

  18. Academic Credit for Prior Learning: 2016 Progress Report

    Science.gov (United States)

    Washington Student Achievement Council, 2017

    2017-01-01

    Students come to college with skills and knowledge acquired through work, military, and other experiences. Academic credit for prior learning is awarded when a student's prior learning is assessed and found to be the equivalent of specific college course outcomes, and when the award of credit is consistent with the policies of the institution.…

  19. On the use of a pruning prior for neural networks

    DEFF Research Database (Denmark)

    Goutte, Cyril

    1996-01-01

    We address the problem of using a regularization prior that prunes unnecessary weights in a neural network architecture. This prior provides a convenient alternative to traditional weight-decay. Two examples are studied to support this method and illustrate its use. First we use the sunspots...

  20. Drunkorexia: Calorie Restriction Prior to Alcohol Consumption among College Freshman

    Science.gov (United States)

    Burke, Sloane C.; Cremeens, Jennifer; Vail-Smith, Karen; Woolsey, Conrad

    2010-01-01

    Using a sample of 692 freshmen at a southeastern university, this study examined caloric restriction among students prior to planned alcohol consumption. Participants were surveyed for self-reported alcohol consumption, binge drinking, and caloric intake habits prior to drinking episodes. Results indicated that 99 of 695 (14%) of first year…

  1. 28 CFR 2.9 - Study prior to sentencing.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Study prior to sentencing. 2.9 Section 2... PRISONERS, YOUTH OFFENDERS, AND JUVENILE DELINQUENTS United States Code Prisoners and Parolees § 2.9 Study prior to sentencing. When an adult Federal offender has been committed to an institution by...

  2. 12 CFR 303.82 - Transactions requiring prior notice.

    Science.gov (United States)

    2010-01-01

    ... company requiring prior notice to the FDIC, if, immediately after the transaction, the acquiring person..., shall give the FDIC 60 days prior written notice, as specified in § 303.84, before acquiring control of an insured state nonmember bank or any parent company, unless the acquisition is exempt under §...

  3. Drunkorexia: Calorie Restriction Prior to Alcohol Consumption among College Freshman

    Science.gov (United States)

    Burke, Sloane C.; Cremeens, Jennifer; Vail-Smith, Karen; Woolsey, Conrad

    2010-01-01

    Using a sample of 692 freshmen at a southeastern university, this study examined caloric restriction among students prior to planned alcohol consumption. Participants were surveyed for self-reported alcohol consumption, binge drinking, and caloric intake habits prior to drinking episodes. Results indicated that 99 of 695 (14%) of first year…

  4. Quantitative utilization of prior biological knowledge in the Bayesian network modeling of gene expression data

    Directory of Open Access Journals (Sweden)

    Gao Shouguo

    2011-08-01

    Full Text Available Abstract Background Bayesian Network (BN is a powerful approach to reconstructing genetic regulatory networks from gene expression data. However, expression data by itself suffers from high noise and lack of power. Incorporating prior biological knowledge can improve the performance. As each type of prior knowledge on its own may be incomplete or limited by quality issues, integrating multiple sources of prior knowledge to utilize their consensus is desirable. Results We introduce a new method to incorporate the quantitative information from multiple sources of prior knowledge. It first uses the Naïve Bayesian classifier to assess the likelihood of functional linkage between gene pairs based on prior knowledge. In this study we included cocitation in PubMed and schematic similarity in Gene Ontology annotation. A candidate network edge reservoir is then created in which the copy number of each edge is proportional to the estimated likelihood of linkage between the two corresponding genes. In network simulation the Markov Chain Monte Carlo sampling algorithm is adopted, and samples from this reservoir at each iteration to generate new candidate networks. We evaluated the new algorithm using both simulated and real gene expression data including that from a yeast cell cycle and a mouse pancreas development/growth study. Incorporating prior knowledge led to a ~2 fold increase in the number of known transcription regulations recovered, without significant change in false positive rate. In contrast, without the prior knowledge BN modeling is not always better than a random selection, demonstrating the necessity in network modeling to supplement the gene expression data with additional information. Conclusion our new development provides a statistical means to utilize the quantitative information in prior biological knowledge in the BN modeling of gene expression data, which significantly improves the performance.

  5. Construction and test of the PRIOR proton microscope; Aufbau und Test des Protonenmikroskops PRIOR

    Energy Technology Data Exchange (ETDEWEB)

    Lang, Philipp-Michael

    2015-01-15

    The study of High Energy Density Matter (HEDM) in the laboratory makes great demands on the diagnostics because these states can usually only be created for a short time and usual diagnostic techniques with visible light or X-rays come to their limit because of the high density. The high energy proton radiography technique that was developed in the 1990s at the Los Alamos National Laboratory is a very promising possibility to overcome those limits so that one can measure the density of HEDM with high spatial and time resolution. For this purpose the proton microscope PRIOR (Proton Radiography for FAIR) was set up at GSI, which not only reproduces the image, but also magnifies it by a factor of 4.2 and thereby penetrates matter with a density up to 20 g/cm{sup 2}. Straightaway a spatial resolution of less than 30 μm and a time resolution on the nanosecond scale was achieved. This work describes details to the principle, design and construction of the proton microscope as well as first measurements and simulations of essential components like magnetic lenses, a collimator and a scintillator screen. For the latter one it was possible to show that plastic scintillators can be used as converter as an alternative to the slower but more radiation resistant crystals, so that it is possible to reach a time resolution of 10 ns. Moreover the characteristics were investigated for the system at the commissioning in April 2014. Also the changes in the magnetic field due to radiation damage were studied. Besides that an overview about future applications is given. First experiments with Warm Dense Matter created by using a Pulsed Power Setup have already been performed. Furthermore the promising concept of combining proton radiography with particle therapy has been investigated in context of the PaNTERA project. An outlook on the possibilities with future experiments at the FAIR accelerator facility is given as well. Because of higher beam intensity an energy one can expect even

  6. Reference priors of nuisance parameters in Bayesian sequential population analysis

    CERN Document Server

    Bousquet, Nicolas

    2010-01-01

    Prior distributions elicited for modelling the natural fluctuations or the uncertainty on parameters of Bayesian fishery population models, can be chosen among a vast range of statistical laws. Since the statistical framework is defined by observational processes, observational parameters enter into the estimation and must be considered random, similarly to parameters or states of interest like population levels or real catches. The former are thus perceived as nuisance parameters whose values are intrinsically linked to the considered experiment, which also require noninformative priors. In fishery research Jeffreys methodology has been presented by Millar (2002) as a practical way to elicit such priors. However they can present wrong properties in multiparameter contexts. Therefore we suggest to use the elicitation method proposed by Berger and Bernardo to avoid paradoxical results raised by Jeffreys priors. These benchmark priors are derived here in the framework of sequential population analysis.

  7. Prior Subject Interest, Students' Evaluations, And Instructional Effectiveness.

    Science.gov (United States)

    Marsh, H W; Cooper, T L

    1981-01-01

    Students' Prior Subject Interest in a course showed similar correlations with student ratings of instructional effectiveness in two university settings (N = 1102 classes). Correlations between Prior Subject Interest and different dimensions of instructional effectiveness varied from approximately zero to .44. Though these correlations were not high, Prior Subject Interest predicted student ratings better than any of 15 other student/course/instructor characteristics considered (e.g., Expected Grade, Class Size, Workload/Difficulty, Teacher Rank). Instructor self-evaluations of their own teaching effectiveness (N = 329 classes) were also positively correlated with both their own and their students' perceptions of Prior Subject Interest; the dimensions that were most highly correlated -- particularly Learning/Value -- were the same as observed with student ratings. Since both student and instructor self evaluations were similarly related to Prior Subject Interest, it appears that this variable actually affects instructional effectiveness in a way that is accurately reflected in the student ratings.

  8. Training shortest-path tractography: Automatic learning of spatial priors

    DEFF Research Database (Denmark)

    Kasenburg, Niklas; Liptrot, Matthew George; Reislev, Nina Linde;

    2016-01-01

    knowledge. Here we demonstrate how such prior knowledge, or indeed any prior spatial information, can be automatically incorporated into a shortest-path tractography approach to produce more robust results. We describe how such a prior can be automatically generated (learned) from a population, and we...... demonstrate that our framework also retains support for conventional interactive constraints such as waypoint regions. We apply our approach to the open access, high quality Human Connectome Project data, as well as a dataset acquired on a typical clinical scanner. Our results show that the use of a learned...... prior substantially increases the overlap of tractography outputwith a reference atlas on both populations, and this is confirmed by visual inspection. Furthermore, we demonstrate how a prior learned on the high quality dataset significantly increases the overlap with the reference for the more typical...

  9. Asymptotic admissibility of priors and elliptic differential equations

    CERN Document Server

    Hartigan, J A

    2010-01-01

    We evaluate priors by the second order asymptotic behavior of the corresponding estimators.Under certain regularity conditions, the risk differences between efficient estimators of parameters taking values in a domain D, an open connected subset of R^d, are asymptotically expressed as elliptic differential forms depending on the asymptotic covariance matrix V. Each efficient estimator has the same asymptotic risk as a 'local Bayes' estimate corresponding to a prior density p. The asymptotic decision theory of the estimators identifies the smooth prior densities as admissible or inadmissible, according to the existence of solutions to certain elliptic differential equations. The prior p is admissible if the quantity pV is sufficiently small near the boundary of D. We exhibit the unique admissible invariant prior for V=I,D=R^d-{0). A detailed example is given for a normal mixture model.

  10. 2-Amino-4-(4-aminophenyl)thiazole application as an ionophore in the construction of a Lu(Ⅲ) selective membrane sensor

    Institute of Scientific and Technical Information of China (English)

    Mohammad Reza Pourjavid; Taherehsadat Razavi

    2012-01-01

    A derivative of thiazole (AAT) has been explored as a sensing material for preparation a selective Lu(Ⅲ) PVC-based membrane sensor.The proposed sensor exhibits a Nernstian response over a wide concentration range from 1.0 × 10-6 to 1.0 × 10-1 mol/L of Lu(Ⅲ) and the detection limit is 5.7 × 10-7 mol/L.The sensor response is independent of pH of the solution in the range 3.2-8.8 and possesses the advantages of fast response time (~6) and in particular,good selectivity to the lutetium ions with regard to most common metal ions,and especiallv all lanthanide ions.

  11. Synthesis of nano-sized arsenic-imprinted polymer and its use as As{sup 3+} selective ionophore in a potentiometric membrane electrode: Part 1

    Energy Technology Data Exchange (ETDEWEB)

    Alizadeh, Taher, E-mail: Alizadeh@uma.ac.ir; Rashedi, Mariyam

    2014-09-16

    Highlights: • The first arsenic cation-selective membrane electrode was introduced. • A novel procedure was introduced for the preparation of As-imprinted polymer. • It was found that arsenic is recognized by the IIP as As{sup 3+} species. • Nernstian response of 20.4 mV decade{sup −1} and DL of 0.5 μM was obtained. - Abstract: In this study, a new strategy was proposed for the preparation of As (III)-imprinted polymer by using arsenic (methacrylate){sub 3} as template. Precipitation polymerization was utilized to synthesize nano-sized As (III)-imprinted polymer. Methacrylic acid and ethylene glycol dimethacrylate were used as the functional monomer and cross-linking agent, respectively. In order to assembly functional monomers around As (III) ion, sodium arsenite and methacrylic acid were heated in the presence of hydroquinone, leading to arsenic (methacrylate){sub 3}. The nano-sized As (III) selective polymer was characterized by FT-IR and scanning electron microscopy techniques (SEM). It was demonstrated that arsenic was recognized as As{sup 3+} by the selective cavities of the synthesized IIP. Based on the prepared polymer, the first arsenic cation selective membrane electrode was introduced. Membrane electrode was constructed by dispersion of As (III)-imprinted polymer nanoparticles in poly(vinyl chloride), plasticized with di-nonylphthalate. The IIP-modified electrode exhibited a Nernstian response (20.4 ± 0.5 mV decade{sup −1}) to arsenic ion over a wide concentration range (7.0 × 10{sup −7} to 1.0 × 10{sup −1} mol L{sup −1}) with a lower detection limit of 5.0 × 10{sup −7} mol L{sup −1}. Unlike this, the non-imprinted polymer (NIP)-based membrane electrode was not sensitive to arsenic in aqueous solution. The selectivity of the developed sensor to As (III) was shown to be satisfactory. The sensor was used for arsenic determination in some real samples.

  12. A 9,10-anthraquinone derivative having two propenyl arms as a neutral ionophore for highly selective and sensitive membrane sensors for copper(II) ion.

    Science.gov (United States)

    Shamsipur, Mojtaba; Avanes, Armen; Javanbakht, Mehran; Ganjali, Mohammad Reza; Sharghi, Hashem

    2002-08-01

    New polymeric membrane (PME) and coated graphite (CGE) copper(II)-selective electrodes based on 1-hydroxy-2-(prop-2'-enyl)-4-(prop-2'-enyloxy)-9,10-anthraquinone were prepared. The electrodes reveal linear emf-pCu2+ responses over wide concentration ranges (1.0 x 10(-5)-1.0 x 10(-1) M with a slope of 27.3 mV decade-1 for PME and 8.0 x 10(-8)-5.0 x 10(-2) M with a slope of 29.1 mV decade-1 for CGE) and very low limits of detection (8.0 x 10(-6) M for PME and 5.0 x 10(-8) M for CGE). The potentiometric response is independent of the pH of the test solution in the pH range 3.0-6.0. The proposed electrodes possess very good selectivities over a wide variety of other cations, including alkali, alkaline earth, transition and heavy metal ions, the selectivity coefficients for the CGE being much improved over those for the PME. The electrodes were used as indicator electrodes in the potentiometric titration of Cu2+ and in the recovery of copper ions from wastewater.

  13. Random geometric prior forest for multiclass object segmentation.

    Science.gov (United States)

    Liu, Xiao; Song, Mingli; Tao, Dacheng; Bu, Jiajun; Chen, Chun

    2015-10-01

    Recent advances in object detection have led to the development of segmentation by detection approaches that integrate top-down geometric priors for multiclass object segmentation. A key yet under-addressed issue in utilizing top-down cues for the problem of multiclass object segmentation by detection is efficiently generating robust and accurate geometric priors. In this paper, we propose a random geometric prior forest scheme to obtain object-adaptive geometric priors efficiently and robustly. In the scheme, a testing object first searches for training neighbors with similar geometries using the random geometric prior forest, and then the geometry of the testing object is reconstructed by linearly combining the geometries of its neighbors. Our scheme enjoys several favorable properties when compared with conventional methods. First, it is robust and very fast because its inference does not suffer from bad initializations, poor local minimums or complex optimization. Second, the figure/ground geometries of training samples are utilized in a multitask manner. Third, our scheme is object-adaptive but does not require the labeling of parts or poselets, and thus, it is quite easy to implement. To demonstrate the effectiveness of the proposed scheme, we integrate the obtained top-down geometric priors with conventional bottom-up color cues in the frame of graph cut. The proposed random geometric prior forest achieves the best segmentation results of all of the methods tested on VOC2010/2012 and is 90 times faster than the current state-of-the-art method.

  14. Learning priors for Bayesian computations in the nervous system.

    Directory of Open Access Journals (Sweden)

    Max Berniker

    Full Text Available Our nervous system continuously combines new information from our senses with information it has acquired throughout life. Numerous studies have found that human subjects manage this by integrating their observations with their previous experience (priors in a way that is close to the statistical optimum. However, little is known about the way the nervous system acquires or learns priors. Here we present results from experiments where the underlying distribution of target locations in an estimation task was switched, manipulating the prior subjects should use. Our experimental design allowed us to measure a subject's evolving prior while they learned. We confirm that through extensive practice subjects learn the correct prior for the task. We found that subjects can rapidly learn the mean of a new prior while the variance is learned more slowly and with a variable learning rate. In addition, we found that a Bayesian inference model could predict the time course of the observed learning while offering an intuitive explanation for the findings. The evidence suggests the nervous system continuously updates its priors to enable efficient behavior.

  15. A New Composition for Co(II-porphyrin-based Membranes Used in Thiocyanate-selective Electrodes

    Directory of Open Access Journals (Sweden)

    Otilia Bizerea-Spiridon

    2006-08-01

    Full Text Available In the present paper, the potentiometric response characteristics of ametalloporphyrin-based electrode in o-nitrophenyloctylether (o-NPOE plasticizedpolyvinyl chloride (PVC membrane are presented for a set of monovalent anions. Asmembrane ionophore, 5,10,15,20-tetrakis-(4-methoxyphenyl-porphyrin-Co(II(CoTMeOPP was used. To establish the optimum composition of the membrane, differentmolar percents of cationic derivative (mol.% relative to ionophore were used. Electrodesformulated with membranes containing 1 wt.% ionophore, 66 wt.% o-NPOE, 33 wt.% PVC(plasticizer: PVC = 2:1 and the lipophilic cationic derivative (35 mol% are shown toexhibit high selectivity for thiocyanate with a near-Nernstian slope in the workingconcentration range of 1.0×10−1–1.0×10−5 M, with a good stability in time.

  16. The gender specific frequency of risk factor and CHD diagnoses prior to incident MI: a community study.

    Science.gov (United States)

    Yawn, Barbara P; Wollan, Peter C; Yawn, Roy A; Jacobsen, Steven J; Roger, Veronique

    2007-04-04

    CHD is a chronic disease often present years prior to incident AMI. Earlier recognition of CHD may be associated with higher levels of recognition and treatment of CHD risk factors that may delay incident AMI. To assess timing of CHD and CHD risk factor diagnoses prior to incident AMI. This is a 10-year population based medical record review study that included all medical care providers in Olmsted County, Minnesota for all women and a sample of men residing in Olmsted County, MN with confirmed incident AMI between 1995 and 2000. All medical care for the 10 years prior to incident AMI was reviewed for 150 women and 148 men (38% sample) in Olmsted County, MN. On average, women were older than men at the time of incident AMI (74.7 versus 65.9 years, p < 0.0001). 30.4% of the men and 52.0% of the women received diagnoses of CHD prior to incident AMI (p = 0.0002). Unrecognized and untreated CHD risk factors were present in both men (45% of men 5 years prior to AMI) and women (22% of women 5 years prior to first AMI), more common in men and those without a diagnosis of CHD prior to incident AMI (p < 0.0001). A CHD diagnosis prior to incident AMI is associated with higher rates of recognition and treatment of CHD risk factors suggesting that diagnosing CHD prior to AMI enhances opportunities to lower the risk of future CHD events.

  17. Drug repurposing and the prior art patents of competitors.

    Science.gov (United States)

    Sternitzke, Christian

    2014-12-01

    Drug repurposing (i.e., finding novel indications for established substances) has received increasing attention in industry recently. One challenge of repositioned drugs is obtaining effective patent protection, especially if the 'novel' indications have already been claimed by competitors within the same drug class. Here, I report the case of patents relating to phosphodiesterase type 5 (PDE5) inhibitors. Patentees of later-filed patents on novel indications (even when they could not observe prior patenting of their direct competitors) filed patents for which patent examiners did not see the prior-filed patents of the competitors as relevant prior art, whereas these follower patent applications often failed because of other reasons.

  18. Assessment of unskilled adults’ prior learning – fair to whom?

    DEFF Research Database (Denmark)

    Aarkrog, Vibe

    2014-01-01

    As in many other countries, Danish adult education policy focuses on how to encourage adults for education; the most important and challenging group of adults being those with few or no formal qualifications. Assessment of prior learning (APL) is perceived as an important tool for motivating adults...... for education and training. The most important part of the adults’ prior learning has been obtained outside the formal school system, typically consisting of their work experiences. This paper discusses research that examined the meeting between on the one hand the adults’ prior learning and on the other...

  19. Prior source exposure and persuasion: further evidence for misattributional processes.

    Science.gov (United States)

    Weisbuch, Max; Mackie, Diane M; Garcia-Marques, Teresa

    2003-06-01

    To assess the persuasive impact of prior source exposure, two studies paired persuasive messages with a source to whom participants had previously been exposed subliminally, explicitly, or not at all. In Experiment 2, participants' attention also was drawn to information that potentially undermined the implications of any reaction to re-exposure. Compared to no exposure, prior subliminal exposure increased the source's persuasiveness, an effect not mediated by source liking. Explicit exposure increased source persuasiveness to the extent that the source was liked more and only absent a recall cue. Results favored misattributional accounts of prior exposure effects.

  20. INFLUENCE OF PRIORS OVER MULTITYPED OBJECT IN EVOLUTIONARY CLUSTERING

    Directory of Open Access Journals (Sweden)

    L.Visalatchi

    2013-02-01

    Full Text Available In recent years, Evolutionary clustering is an evolving research area in data mining. The evolution diagnosis of any homogeneous as well as heterogeneous network will provide an overall view about the network. Applications of evolutionary clustering includes, analyzing, the social networks, information networks, about their structure, properties and behaviors. In this paper, the authors study the problem of influence of priors over multi-typed object in evolutionary clustering. Priors are defined for each type of object in a heterogeneous information network and experimental results were produced to show how consistency and quality of cluster changes according to the priors.

  1. BAYESIAN ESTIMATION OF ERLANG DISTRIBUTION UNDER DIFFERENT PRIOR DISTRIBUTIONS

    Directory of Open Access Journals (Sweden)

    Abdul Haq

    2011-01-01

    Full Text Available This paper addresses the problem of Bayesian estimation of the parameters of Erlangdistribution under squared error loss function by assuming different independent informativepriors as well as joint priors for both shape and scale parameters. The motivation is to explore themost appropriate prior for Erlang distribution among different priors. A comparison of the Bayesestimates and their risks for different choices of the values of the hyperparameters is alsopresented. Finally, we illustrate the results using a simulation study as well as by doing real dataanalysis.

  2. A simple shape prior model for iris image segmentation

    Science.gov (United States)

    Bishop, Daniel A.; Yezzi, Anthony, Jr.

    2011-06-01

    In order to make biometric systems faster and more user-friendly, lower-quality images must be accepted. A major hurdle in this task is accurate segmentation of the boundaries of the iris in these images. Quite commonly, circle-fitting is used to approximate the boundaries of the inner (pupil) and outer (limbic) boundaries of the iris, but this assumption does not hold for off-axis or otherwise non-circular boundaries. In this paper we present a novel, foundational method for elliptical segmentation of off-axis iris images. This method uses active contours with constrained flow to achieve a simplified form of shape prior active contours. This is done by calculating a region-based contour evolution and projecting it upon a properly chosen set of vectors to confine it to a class of shapes. In this case, that class of shapes is ellipses. This serves to regularize the contour, simplifying the curve evolution and preventing the development of irregularities that present challenges in iris segmentation. The proposed method is tested using images from the UBIRIS v.1 and CASIA-IrisV3 image data sets, with both near-ideal and off-axis images. Additional testing has been performed using the WVU Off Axis/Angle Iris Dataset, Release 1. By avoiding many of the assumptions commonly used in iris segmentation methods, the proposed method is able to accurately fit elliptical boundaries to off-axis images.

  3. An Ensemble Approach to Building Mercer Kernels with Prior Information

    Science.gov (United States)

    Srivastava, Ashok N.; Schumann, Johann; Fischer, Bernd

    2005-01-01

    This paper presents a new methodology for automatic knowledge driven data mining based on the theory of Mercer Kernels, which are highly nonlinear symmetric positive definite mappings from the original image space to a very high, possibly dimensional feature space. we describe a new method called Mixture Density Mercer Kernels to learn kernel function directly from data, rather than using pre-defined kernels. These data adaptive kernels can encode prior knowledge in the kernel using a Bayesian formulation, thus allowing for physical information to be encoded in the model. Specifically, we demonstrate the use of the algorithm in situations with extremely small samples of data. We compare the results with existing algorithms on data from the Sloan Digital Sky Survey (SDSS) and demonstrate the method's superior performance against standard methods. The code for these experiments has been generated with the AUTOBAYES tool, which automatically generates efficient and documented C/C++ code from abstract statistical model specifications. The core of the system is a schema library which contains templates for learning and knowledge discovery algorithms like different versions of EM, or numeric optimization methods like conjugate gradient methods. The template instantiation is supported by symbolic-algebraic computations, which allows AUTOBAYES to find closed-form solutions and, where possible, to integrate them into the code.

  4. Ionospheric characteristics prior to the greatest earthquake in recorded history

    Science.gov (United States)

    Villalobos, C. U.; Bravo, M. A.; Ovalle, E. M.; Foppiano, A. J.

    2016-03-01

    Although several reports on the variations of some radio observed ionospheric properties prior to the very large Chile earthquakes of 21-22 May 1960 have been published, no one up to now has reported on the variations of simultaneous E- and F-region characteristics observed at Concepción (36.8°S; 73.0°W) using a ground based ionosonde. This paper analyses values of the NmE, NmEs, h'E, NmF2, h'F, M3000F2 and fmin. Possible solar and geomagnetic activity effects are first identified and then anomalies are calculated for all characteristics using reference values (15-day running medians ± interquartile range). Occasions when anomalies are larger than an upper threshold and less than a lower threshold are discussed and compared, whenever possible, with other published studies. Further study is suggested to unambiguously associate some found possible Es-layer and M3000F2 anomalies with very strong earthquakes.

  5. A Ban on Prior Restraint in High Schools: The Aftermath of the "Fujishima" Decision.

    Science.gov (United States)

    Trager, Robert; Dickerson, Donna L.

    After a unique court decision forbidding prior restraint in public high school publications in three states, a study was devised based on the responses to individual questionnaires sent to principals, faculty advisers, and student editors in each of the schools in the judicial district involved in the decision. Respondents answered questions…

  6. President Nixon speaks at Hickam AFB prior to presenting Medal of Freedom

    Science.gov (United States)

    1970-01-01

    President Richard M. Nixon speaks at Hickam Air Force Base prior to presenting the nation's highest civilian award to the Apollo 13 crew. Receiving the Presidential Medal of Freedom were Astronauts James A. Lovell Jr. (next to the Chief Executive), commander; John L. Swigert Jr. (left), command module pilot; and Fred W. Haise Jr., lunar module pilot.

  7. Relevant Prior Knowledge Moderates the Effect of Elaboration during Small Group Discussion on Academic Achievement

    Science.gov (United States)

    Van Blankenstein, Floris M.; Dolmans, Diana H. J. M.; Van der Vleuten, Cees P. M.; Schmidt, Henk G.

    2013-01-01

    This study set out to test whether relevant prior knowledge would moderate a positive effect on academic achievement of elaboration during small-group discussion. In a 2 × 2 experimental design, 66 undergraduate students observed a video showing a small-group problem-based discussion about thunder and lightning. In the video, a teacher asked…

  8. Relevant prior knowledge moderates the effect of elaboration during small group discussion on academic achievement

    NARCIS (Netherlands)

    F.M. van Blankenstein (Floris); D.H.J.M. Dolmans (Diana); C.P.M. van der Vleuten (Cees); H.G. Schmidt (Henk)

    2013-01-01

    textabstractThis study set out to test whether relevant prior knowledge would moderate a positive effect on academic achievement of elaboration during small-group discussion. In a 2 × 2 experimental design, 66 undergraduate students observed a video showing a small-group problem-based discussion

  9. Assessors' Approaches to Portfolio Assessment in Assessment of Prior Learning Procedures

    Science.gov (United States)

    Joosten-ten Brinke, Desiree; Sluijsmans, Dominique M. A.; Jochems, Wim M. G.

    2010-01-01

    In an effort to gain better understanding of the assessment of prior informal and non-formal learning, this article explores assessors' approaches to portfolio assessment. Through this portfolio assessment, candidates had requested exemptions from specific courses within an educational programme or admission to the programme based on their prior…

  10. Behavior Segmentation by Boys as a Function of Aggressiveness and Prior Information.

    Science.gov (United States)

    Courtney, Mary Lynne; Cohen, Robert

    1996-01-01

    Examined whether aggressive boys' hostile attribution bias extends to processing incoming information. Subjects were asked to segment videotaped actions based on information conditions about the two boys playing in the film. Aggressiveness predicted change in segmentation after the critical event only in the neutral prior-information condition,…

  11. Feedback Both Helps and Hinders Learning: The Causal Role of Prior Knowledge

    Science.gov (United States)

    Fyfe, Emily R.; Rittle-Johnson, Bethany

    2016-01-01

    Feedback can be a powerful learning tool, but its effects vary widely. Research has suggested that learners' prior knowledge may moderate the effects of feedback; however, no causal link has been established. In Experiment 1, we randomly assigned elementary school children (N = 108) to a condition based on a crossing of 2 factors: induced strategy…

  12. Can Prior Knowledge Hurt Text Comprehension? An Answer Borrowed from Plato, Aristotle, and Descartes.

    Science.gov (United States)

    Friedman, Lawrence B.

    Taking a philosophical approach based on what Plato, Aristotle, and Descartes said about knowledge, this paper addresses some of the murkiness in the conceptual space surrounding the issue of whether prior knowledge does or does not facilitate text comprehension. Specifically, the paper first develops a non-exhaustive typology of cases in which…

  13. Enhancement of mobile C-arm cone-beam reconstruction using prior anatomical models

    Science.gov (United States)

    Sadowsky, Ofri; Lee, Junghoon; Sutter, Edward G.; Wall, Simon J.; Prince, Jerry L.; Taylor, Russell H.

    2009-02-01

    We demonstrate an improvement to cone-beam tomographic imaging by using a prior anatomical model. A protocol for scanning and reconstruction has been designed and implemented for a conventional mobile C-arm: a 9 inch image-intensifier OEC-9600. Due to the narrow field of view (FOV), the reconstructed image contains strong truncation artifacts. We propose to improve the reconstructed images by fusing the observed x-ray data with computed projections of a prior 3D anatomical model, derived from a subject-specific CT or from a statistical database (atlas), and co-registered (3D/2D) to the x-rays. The prior model contains a description of geometry and radiodensity as a tetrahedral mesh shape and density polynomials, respectively. A CT-based model can be created by segmentation, meshing and polynomial fitting of the object's CT study. The statistical atlas is created through principal component analysis (PCA) of a collection of mesh instances deformably-registered (3D/3D) to patient datasets. The 3D/2D registration method optimizes a pixel-based similarity score (mutual information) between the observed x-rays and the prior. The transformation involves translation, rotation and shape deformation based on the atlas. After registration, the image intensities of observed and prior projections are matched and adjusted, and the two information sources are blended as inputs to a reconstruction algorithm. We demonstrate recostruction results of three cadaveric specimens, and the effect of fusing prior data to compensate for truncation. Further uses of hybrid reconstruction, such as compensation for the scan's limited arc length, are suggested for future research.

  14. A Bayesian Approach for Image Segmentation with Shape Priors

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Hang; Yang, Qing; Parvin, Bahram

    2008-06-20

    Color and texture have been widely used in image segmentation; however, their performance is often hindered by scene ambiguities, overlapping objects, or missingparts. In this paper, we propose an interactive image segmentation approach with shape prior models within a Bayesian framework. Interactive features, through mouse strokes, reduce ambiguities, and the incorporation of shape priors enhances quality of the segmentation where color and/or texture are not solely adequate. The novelties of our approach are in (i) formulating the segmentation problem in a well-de?ned Bayesian framework with multiple shape priors, (ii) ef?ciently estimating parameters of the Bayesian model, and (iii) multi-object segmentation through user-speci?ed priors. We demonstrate the effectiveness of our method on a set of natural and synthetic images.

  15. What good are actions? Accelerating learning using learned action priors

    CSIR Research Space (South Africa)

    Rosman, Benjamin S

    2012-11-01

    Full Text Available The computational complexity of learning in sequential decision problems grows exponentially with the number of actions available to the agent at each state. We present a method for accelerating this process by learning action priors that express...

  16. Cosmological limits on neutrino unknowns versus low redshift priors

    CERN Document Server

    Di Valentino, Eleonora; Mena, Olga; Melchiorri, Alessandro; Silk, Joseph

    2015-01-01

    Recent Cosmic Microwave Background (CMB) temperature and polarization anisotropy measurements from the Planck mission have significantly improved previous constraints on the neutrino masses as well as the bounds on extended models with massless or massive sterile neutrino states. However, due to parameter degeneracies, additional low redshift priors are mandatory in order to sharpen the CMB neutrino bounds. We explore here the role of different priors on low redshift quantities, such as the Hubble constant, the cluster mass bias, and the reionization optical depth $\\tau$. Concerning current priors on the Hubble constant and the cluster mass bias, the bounds on the neutrino parameters may differ appreciably depending on the choices adopted in the analyses. With regard to future improvements in the priors on the reionization optical depth, a value of $\\tau=0.05\\pm 0.01$, motivated by astrophysical estimates of the reionization redshift, would lead to $\\sum m_\

  17. Photometric Redshift with Bayesian Priors on Physical Properties of Galaxies

    CERN Document Server

    Tanaka, Masayuki

    2015-01-01

    We present a proof-of-concept analysis of photometric redshifts with Bayesian priors on physical properties of galaxies. This concept is particularly suited for upcoming/on-going large imaging surveys, in which only several broad-band filters are available and it is hard to break some of the degeneracies in the multi-color space. We construct model templates of galaxies using a stellar population synthesis code and apply Bayesian priors on physical properties such as stellar mass and star formation rate. These priors are a function of redshift and they effectively evolve the templates with time in an observationally motivated way. We demonstrate that the priors help reduce the degeneracy and deliver significantly improved photometric redshifts. Furthermore, we show that a template error function, which corrects for systematic flux errors in the model templates as a function of rest-frame wavelength, delivers further improvements. One great advantage of our technique is that we simultaneously measure redshifts...

  18. Investigation into alternative sludge conditioning prior to dewatering

    CSIR Research Space (South Africa)

    Smollen, M

    1997-01-01

    Full Text Available The principal objective of this work is to provide a more effective alternative for sludge conditioning prior to mechanical dewatering. The common use of polyelectrolytes often results in the anal cake solids concentration not sufficiently high...

  19. Form of prior for constrained thermodynamic processes with uncertainty

    Science.gov (United States)

    Aneja, Preety; Johal, Ramandeep S.

    2015-05-01

    We consider the quasi-static thermodynamic processes with constraints, but with additional uncertainty about the control parameters. Motivated by inductive reasoning, we assign prior distribution that provides a rational guess about likely values of the uncertain parameters. The priors are derived explicitly for both the entropy-conserving and the energy-conserving processes. The proposed form is useful when the constraint equation cannot be treated analytically. The inference is performed using spin-1/2 systems as models for heat reservoirs. Analytical results are derived in the high-temperatures limit. An agreement beyond linear response is found between the estimates of thermal quantities and their optimal values obtained from extremum principles. We also seek an intuitive interpretation for the prior and the estimated value of temperature obtained therefrom. We find that the prior over temperature becomes uniform over the quantity kept conserved in the process.

  20. Structural prediction of dynamic Bayesian network with partial prior information.

    Science.gov (United States)

    Maiti, Aniruddha; Reddy, Ramakanth; Mukherjee, Anirban

    2015-01-01

    The prediction of the structure of a hidden dynamic Bayesian network (DBN) from a noisy dataset is an important and challenging task. This work presents a generalized framework to infer the DBN network structure with partial prior information. In the proposed framework, the partial information about the network structure is provided in the form of prior. The proposed method makes use of the prior information regarding the presence and as well as absence of some of the edges. Using the noisy dataset and partial prior information, this method is able to infer nearly accurate structure of the network. The proposed method is validated using simulated datasets. In addition, two real biological datasets are used to infer hidden biological interaction networks.