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1

PHOTOMETRIC TITRATION OF SCANDIUM  

Microsoft Academic Search

A scandium solution containing copper(IV) can be titrated ; photometrically in acid solution with (ethylenedinitrilo)tetraacetic acid (EDTA) ; in the presence of up to 60 times as much rare earth (on a molar basis). The ; absorbance of copper(IV)-EDTA at745 m mu is used a follow the course of the ; titration. Large amounts of aluminum (III), calcium (II), magnesium

James Fritz; Donald Pietrzyk

1959-01-01

2

A Full Automatic Device for Sampling Small Solution Volumes in Photometric Titration Procedure Based on Multicommuted Flow System  

PubMed Central

In this work, an automatic device to deliver titrant solution into a titration chamber with the ability to determine the dispensed volume of solution, with good precision independent of both elapsed time and flow rate, is proposed. A glass tube maintained at the vertical position was employed as a container for the titrant solution. Electronic devices were coupled to the glass tube in order to control its filling with titrant solution, as well as the stepwise solution delivering into the titration chamber. The detection of the titration end point was performed employing a photometer designed using a green LED (?=545 nm) and a phototransistor. The titration flow system comprised three-way solenoid valves, which were assembled to allow that the steps comprising the solution container loading and the titration run were carried out automatically. The device for the solution volume determination was designed employing an infrared LED (?=930 nm) and a photodiode. When solution volume delivered from proposed device was within the range of 5 to 105 ?l, a linear relationship (R = 0.999) between the delivered volumes and the generated potential difference was achieved. The usefulness of the proposed device was proved performing photometric titration of hydrochloric acid solution with a standardized sodium hydroxide solution and using phenolphthalein as an external indicator. The achieved results presented relative standard deviation of 1.5%.

Borges, Sivanildo S.; Vieira, Glaucia P.; Reis, Boaventura F.

2007-01-01

3

Complexometric photometric titrations without an indicator.  

PubMed

Calculations of titration curves in advance with the aid of conditional constants saves some experimental work. The limits of a conventional titration curve are determined, the titration of lead with EDTA being used as an example. PMID:18962641

von Haartman, C

1980-02-01

4

Automatic photometric titrations of calcium and magnesium in carbonate rocks  

USGS Publications Warehouse

Rapid nonsubjective methods have been developed for the determination of calcium and magnesium in carbonate rocks. From a single solution of the sample, calcium is titrated directly, and magnesium is titrated after a rapid removal of R2O3 and precipitation of calcium as the tungstate. A concentrated and a dilute solution of disodium ethylenediamine tetraacetate are used as titrants. The concentrated solution is added almost to the end point, then the weak solution is added in an automatic titrator to determine the end point precisely.

Shapiro, L.; Brannock, W. W.

1955-01-01

5

Complexometric titration of submicromole amounts of thorium(IV) with photometric end-point detection  

Microsoft Academic Search

Summary Thorium(IV) can be determined in the microgram range by photometric titration with EDTA in the presence of an approximately equivalent amount of the indicator Semi-Xylenol Orange at pH 2 (HClO4). Most other elements do not interfere. Interfering metal ions can be separated from thorium(IV) by electrolysis at a mercury pool cathode.

C. J. C. Pijpers; L. G. Decnop-Weever; G. den Boef; W. E. van der Linden

1976-01-01

6

Complexometric Titration of Calcium and Magnesium by a Semiautomated Procedure  

Microsoft Academic Search

A semiautomatic procedure for the direct estimation of both serum calcium and magnesiumis described. The indicator used, Eriochromeblue SE (EBSE), has the advantageof stability and freedom from interference by naturally occurring sub- stances. The procedurerequires3-5 mm. per sampleand is very reproducible. The valuesobtainedagreewith thoseobtainedbyback-titration of excesschelator andare consistently0.3 mg.\\/100 ml. lessthan thoseobtainedbyastandardoxalateprecipita- tion method. C OMPLEXOMETRIC TITRATION s of calcium

James D. Jonesand; Warren F. McGuckin

7

Determination of cationic polyelectrolytes using a photometric titration with crystal violet as a color indicator.  

PubMed

The reaction of the cationic dye, crystal violet (CV) with the anionic polyelectrolytes such as potassium poly (vinyl sulfate) (PVSK) results in a decrease of the absorbance of CV at the maximum absorption wavelength (590 nm). This change of the absorption spectra of the CV has been already applied to the determination of anionic polyelectrolytes using flow injection analysis method. In this paper, CV was applied to the indicator for the determination of cationic polyelectrolytes such as poly (diallyldimethylammonium chloride) (Cat-floc) by photometric titration, using a PVSK solution as a titrant. The end-point of the titration is detected as the break point of the titration curve. A linear relationship between the concentration of cationic polyelectrolyte and the end-point volume of the titrant exists in the concentration range from 0 to 5 x 10(-5) eq. mol dm(-3) for Cat-floc, glycol chitosan and methylglycol chitosan. The effects of the concentration of CV and coexisting electrolytes in the sample solution and the effect of pH of the sample solution on the degree of the change of absorbance at the end-point were also examined. PMID:18968953

Masadome, Takashi

2003-03-10

8

Titration  

NSDL National Science Digital Library

The purpose of this project is to construct a mathematical model describing the effects of titration, and then to use that model to determine the concentration and the identity of an acid in a solution by fitting the model to real titration data.

Smith, David

2002-01-16

9

Development and validation of a photometric titration method for the quantitation of sodium chondroitin sulfate (bovine) in Cosequin® DS chewable tablet  

Microsoft Academic Search

A photometric titration method was developed and validated to quantitate sodium chondroitin sulfate in raw materials and Cosequin® DS chewable tablet11Cosequin® DS chewable tablet contains glucosamine HCl, sodium chondroitin sulfate, manganese ascorbate, and flavoring agents.. About 0.1% (w\\/v) cetylpyridinium chloride was used to titrate sodium chondroitin sulfate with photometric indication at wavelengh 420 nm. The standard curves for sodium chondroitin

Zhongming Liang; Corrine Bonneville; Terrin Senez; Todd Henderson

2002-01-01

10

Optical Radiation Measurements: Photometric Calibration Procedures.  

National Technical Information Service (NTIS)

The National Bureau of Standards supplies calibrations of luminous intensity, luminous flux and color temperature on a routine basis. The procedures, equipment and techniques used to perform these calibrations as of October 1972 are described. Details of ...

V. I. Burns D. A. McSparron

1972-01-01

11

Revisiting titration procedures for the determination of exchangeable acidity and exchangeable aluminum in soils  

Microsoft Academic Search

The use of 1 mol L ammonium chloride (NH4Cl) or ammonium nitrate (NH4NO3) solutions as alternative soil extractants were evaluated for the determination of the exchangeable acidity and exchangeable aluminum (Al) in twelve soil samples by the traditional titration\\/back?titration method. The exchangeable Al results were compared with those obtained by inductively coupled plasma emission spectrometry (ICP?AES) measurements while the exchangeable

Aline Renée Coscione; João Carlos de Andrade; Bernardo van Raij

1998-01-01

12

LIGHT TITRATIONS  

PubMed Central

1. The usefulness of the radiomicrometer in titration work has been pointed out. The authors suggest that light titration may also be used where a reaction mixture changes its absorption in the (near) infra-red. 2. The applicability of this method to the starch-iodine reaction has been demonstrated.

Field, John; Baas-Becking, Lourens G. M.

1926-01-01

13

Titrimetric and photometric methods for determination of hypochlorite in commercial bleaches  

Microsoft Academic Search

Two methods, simple titration and photometric methods for determination of hypochlorite are developed, based its reaction with hydrogen peroxide and titration of the residual peroxide by acidic permanganate. In the titration method, the residual hydrogen peroxide is estimated by titration with standard permanganate solution to estimate the hypochlorite concentration. The photometric method is devised to measure the concentration of remaining

Sreekanth B. Jonnalagadda; Prabhashini Gengan

2010-01-01

14

Convergence-optimized procedure for applying the NICA-Donnan model to potentiometric titrations of humic substances.  

PubMed

Despite the high success of the NICA-Donnan (N-D) model to describe the interaction of protons and metal ions with natural organic matter, the large number of fit parameters is a major hindrance to its capacity to provide unique numerical solutions. This well-known difficulty is reflected in the unusually low value of the generic proton binding constant for carboxylic-type groups of fulvic acid (pK(H1) = 2.34), and to some extent of humic acid (2.93), and by the considerable covariance of the other generic N-D parameters. In some studies, the number of parameters obtained by regression is reduced by estimating some values independently with other techniques. Alternatively, the applicability of the model can be improved by devising a rigorous simulation procedure, which constrains the model-fit to converge toward chemically and physically realistic values. A procedure based on three successive iterations is proposed, and the solution is shown to be stable and invariant with the initial set of parameter values. The new generic parameters, in particular pK(H1)(FA) = 3.54 and pK(H1)(HA) = 3.87, derived from the same data set as the previous generic parameters, are in better agreement with literature data. PMID:20704219

Lenoir, Thomas; Matynia, Anthony; Manceau, Alain

2010-08-15

15

Determination of traces of zinc by fluorimetrically indicated complexometric titrations.  

PubMed

Zinc forms fluorescent complexes with 8-hydroxyquinoline-5-sulphonic acid (HQS) in the pH region 7-10. The stability of these complexes is such that two different titration procedures are possible: the titration of zinc with HQS and the titration of zinc with EDTA in the presence of HQS. For both procedures the choice of the titration conditions is described. Also two separation procedures for zinc are described, especially suitable in connection with the EDTA titration. The practical results show that zinc in concentrations larger than 10(-6)M (0.05 mug/ml) can be titrated with good precision. PMID:18961340

van Slageren, R; den Boef, G; van der Linden, W E

1973-08-01

16

Video Observations Encompassing the 2002 Leonid Storm: First Results and a Revised Photometric Procedure for Video Meteor Analysis  

NASA Technical Reports Server (NTRS)

During the 2001 Leonid storm, Marshall Space Flight Center, with the cooperation of the University of Western Ontario and the United States Air Force, deployed 6 teams of observers equipped with intensified video systems to sites located in North America, the Pacific, and Mongolia. The campaign was extremely successful, with the entire period of enhanced Leonid activity (over 16 hours) captured on video tape in a consistent manner. We present the first results from the analysis of this unique, 2 terabyte data set and discuss the problems involved in reducing large amounts of video meteor data. In particular, the question of how to determine meteor masses though photometric analysis will be re-examined, and new techniques will be proposed that eliminate some of the deficiencies suffered by the techniques currently employed in video meteor analysis.

Cooke, William J.; Suggs, Robert M.; Swift, Wesley; Gural, Peter S.; Brown, Peter; Parker, Nelson C. (Technical Monitor)

2002-01-01

17

COMPLEXOMETRICAL TITRATION. XXXIV. \\  

Microsoft Academic Search

The possibility of using Chromeazurol S for the titration of Th, Ni, Ce, ; La, and other rare earth elements was investigated. The interfering ions were ; determined, and the means of eliminating them were studied. (J.S.R.);

M. Malat; M. Tenorova

1957-01-01

18

A titration procedure of the Junonia coenia densovirus and quantitation of transfection by its cloned genomic DNA in four lepidopteran cell lines.  

PubMed

A sensitive and reproducible tissue culture biossay method was developed based on indirect immunofluorescence to titrate virus suspensions of the Junonia coenia densovirus (JcDNV) and to quantify transfections by its cloned genomic DNA. Four lepidopteran cell lines, the SPC-SL 52 from Spodoptera littoralis, the SPC-PL 40 and the SPC-PL 65 cells derived from Spodoptera litura ovaries and hemocytes, respectively, and the SC-LD 135 from Lymantria dispar were compared for their efficiency to support viral replication. The viral titres expressed as TCID50/ml averaged 10(5) for SPC-SL 52, SPC-PL 40 and SC-LD 135 cells, but were above 10(7) for SPC-PL 65 cells. Even with this most sensitive cell line, the rate of infected cells did not exceed 75% and decreased progressively by serial subcultures. Two transfection protocols were used to compare the sensitivity of the same four cell lines to a recombinant plasmid encompassing an infectious sequence of JcDNV genome. SPC-SL 52 cells were found to be the most sensitive, and the lipofection method resulted in about a 5-fold increase compared to the calcium phosphate precipitation protocol. The rescued virions proved to be infectious and the restriction profiles of their DNA were identical to that of wild type virions. PMID:8919823

Li, Y; Jousset, F X; Giraud, C; Rolling, F; Quiot, J M; Bergoin, M

1996-03-01

19

Optimization of a single-drop microextraction procedure for the determination of organophosphorus pesticides in water and fruit juice with gas chromatography-flame photometric detection.  

PubMed

A single-drop microextraction (SDME) procedure was developed for the analysis of organophosphorus pesticides (OPPs) in water and fruit juice by gas chromatography (GC) with flame photometric detection (GC-FPD). The significant parameters affecting the SDME performance such as selection of microextraction solvent, solvent volume, extraction time, stirring rate, sample pH and temperature, and ionic strength were studied and optimized. Two types of SDME mode, static and cycle-flow SDME, were evaluated. The static SDME procedure provided more sensitive analysis of the target analytes. Therefore, static SDME with tributyl phosphate (TBP) as internal standard was selected for the real sample analysis. The limits of detection (LODs) in water for the six studied compounds were between 0.21 and 0.56ng/mL with the relative standard deviations ranging from 1.7 to 10.0%. Linear response data was obtained in the concentration range of 0.5-50ng/mL (except for dichlorvos 1.0-50ng/mL) with correlation coefficients from 0.9995 to 0.9999. Environmental water sample collected from East Lake and fruit juice samples were successfully analyzed using the proposed method, but none of the analytes in both lake water and fruit juice were detected. The recoveries for the spiked water and juice samples were from 77.7 to 113.6%. Compared with the conventional methods, the proposed method enabled a rapid and simple determination of organophosphorus pesticides in water and fruit juice with minimal solvent consumption and a higher concentration capability. PMID:18970647

Xiao, Qin; Hu, Bin; Yu, Chunhe; Xia, Linbo; Jiang, Zucheng

2006-06-15

20

Filtrates & Residues: Olfactory Titration.  

ERIC Educational Resources Information Center

Presents an experiment that uses a unique acid-base indicator--the odor of raw onion--to indicate the end point of the titration of sodium hydroxide with hydrochloric acid. Allows the student to detect the completion of the neutralization reaction by olfaction rather than sight. (JRH)

Wood, John T.; Eddy, Roberta M.

1996-01-01

21

Colloid Titration--A Rapid Method for the Determination of Charged Colloid.  

ERIC Educational Resources Information Center

"Colloid titration" is a volumetric method for determining charged polyelectrolytes in aqueous solutions. The principle of colloid titration, reagents used in the procedure, methods of endpoint detection, preparation of reagent solutions, general procedure used, results obtained, and pH profile of colloid titration are considered. (JN)

Ueno, Keihei; Kina, Ken'yu

1985-01-01

22

Neutron absorptiometric titration.  

PubMed

A method is outlined for detection of two-phase titration end-points by means of an abrupt change in the neutron-absorption characteristics of one of the phases. One of the components of the precipitate must have a large neutron absorption cross-section, and the disappearance or appearance of neutron absorption by the supernatant liquid from the precipitation reaction then marks the completion of precipitation. PMID:18960115

Tölgyessy, J; Varga, S; Dillinger, P

1967-03-01

23

Spectrophotometric Titration of a Mixture of Calcium and Magnesium.  

ERIC Educational Resources Information Center

Describes a spectrophotometric titration experiment which uses a manual titration spectrophotometer and manually operated buret, rather than special instrumentation. Identifies the equipment, materials, and procedures needed for the completion of the experiment. Recommends the use of this experiment in introductory quantitative analysis…

Fulton, Robert; And Others

1986-01-01

24

pH Static Titration: A Quasistatic Approach  

ERIC Educational Resources Information Center

The pH-static titration is applicable to those systems where at least two types of reactions occur in comparable intensities. The commonalities in titrimetric procedure realized according to pH-static titration, irrespective of the kind of chemical processes occurring are discussed.

Michalowski, Tadeusz; Toporek, Marcin; Rymanowski, Maciej

2007-01-01

25

Titration Curves: Fact and Fiction.  

ERIC Educational Resources Information Center

Discusses ways in which datalogging equipment can enable titration curves to be measured accurately and how computing power can be used to predict the shape of curves. Highlights include sources of error, use of spreadsheets to generate titration curves, titration of a weak acid with a strong alkali, dibasic acids, weak acid and weak base, and…

Chamberlain, John

1997-01-01

26

Spectrophotometric titration of zirconium in siliceous materials.  

PubMed

An accurate and selective complexometric titration procedure based upon a spectrophotometrically detected end-point has been developed for the determination of zirconium in glasses, glass-ceramics and refractories. A p-bromomandelic acid separation step for zirconium imparts excellent selectivity to the procedure. The method is particularly important for the 1-5% concentration range where a simple, accurate and selective method for the determination of zirconium has been lacking. PMID:18962344

Sugawara, K F; Su, Y S; Strzegowski, W R

27

Thermometric titration of polysulfides  

SciTech Connect

A novel calorimetric approach has been developed for analyzing mixtures of sulfides and polysulfides in aqueous solution, where the moieties HS/sup -/, S/sub 2//sup 2 -/, S/sub 3//sup 2 -/, S/sub 4//sup 2 -/, and S/sub 5//sup 2 -/ are in dynamic equilibrium. Advantage is taken of their Lewis base reactivities with the organomercury Lewis acid zwitterion /sup -/OOCPhHg/sup +/. On the basis of judicious thermochemical considerations, samples are titrated to thermometric end points with standard p-hydroxymercuribenzoate. Quantitation of sulfidic and polysulfidic sulfur concentrations is feasible in a single experiment. Sulfidic sulfur can be estimated at concentration levels as low as 0.0001 M. Polysulfidic sulfur is amenable to determination even in the presence of a more than 40-fold excess of sulfide. Capabilities of the method are documented by the analysis of synfuel process stream specimens. Precision and accuracy of 1-3% were attained.

Stahl, J.W.; Jordan, J.

1987-04-15

28

Fibre-optic titrations-IV Direct complexometric titration of aluminium(III) with DCTA.  

PubMed

The end-point of the direct complexometric titration of Al(3+) in pH 4.6 solution can be determined by monitoring the fluorescence intensity of the aluminium-morin complex, by use of a bifurcated fibre-optic light guide. The method allows the determination of aluminium in the 1-800 ppm range with good precision. The procedure is applicable even when the solutions are strongly coloured or turbid, but because of the slow complexation kinetics requires a titration time of about 20 min. PMID:18964217

Wolfbeis, O S; Schaffar, B P; Chalmers, R A

1986-11-01

29

Acid-Base Titration Applet  

NSDL National Science Digital Library

Acid-Base titration applet that plots pH changes as student adds acid or base. Gives choice of indicators (only two right now). Compares plots for titration of traditional solution and a buffered solution (several choices for comparison). Can alter starting concentrations.

Usc

30

Titrimetric and photometric methods for determination of hypochlorite in commercial bleaches.  

PubMed

Two methods, simple titration and photometric methods for determination of hypochlorite are developed, based its reaction with hydrogen peroxide and titration of the residual peroxide by acidic permanganate. In the titration method, the residual hydrogen peroxide is estimated by titration with standard permanganate solution to estimate the hypochlorite concentration. The photometric method is devised to measure the concentration of remaining permanganate, after the reaction with residual hydrogen peroxide. It employs 4 ranges of calibration curves to enable the determination of hypochlorite accurately. The new photometric method measures hypochlorite in the range 1.90 x 10(-3) to 1.90 x 10(-2) M, with high accuracy and with low variance. The concentrations of hypochlorite in diverse commercial bleach samples and in seawater which is enriched with hypochlorite were estimated using the proposed method and compared with the arsenite method. The statistical analysis validates the superiority of the proposed method. PMID:20446147

Jonnalagadda, Sreekanth B; Gengan, Prabhashini

2010-01-01

31

Coulometric titration of urea with electrogenerated hypobromite.  

PubMed

A definitive method is described for the indirect assay of several tens of milligrams of urea by coulometric titration. Urea was decomposed in concentrated sulfuric acid using a Kjeldahl flask. Subsequently, the formed ammonium ion was titrated with electrogenerated hypobromite ion in a sodium bromide-sodium tetraborate medium of pH 8.6, with amperometric end-point detection. Parameters affecting the pretreatment procedure were evaluated. The optimized conditions included the heating of 2 g of urea at around 300°C for 2 h with 10 cm(3) of sulfuric acid. Under the proposed conditions, the assay value with expanded uncertainty (k = 2), 99.870 ± 0.026%, agreed well with the certified value of NIST SRM 912a urea, 99.9 ± 0.1%. PMID:23842420

Kato, Jun; Koseki, Takuma; Aoki, Yukie; Yamada, Ayako; Tanaka, Tatsuhiko

2013-01-01

32

Automatic Stepwise Potentiometric Titration in a Monosegmented Flow System  

Microsoft Academic Search

.  ?An automatic stepwise potentiometric titration carried out in a monosegmented flow system is proposed. A tubular hydrogen\\u000a ion-selective electrode without inner reference solution was employed as sensor. The titration procedure was implemented by\\u000a exploiting continuous variations in volumetric fractions achieved by inserting different sample and titrant aliquots into\\u000a the analytical path and maintaining the sample zone volume. Every sample plug

Eduardo P. Borges; Patrícia B. Martelli; Boaventura F. Reis

2000-01-01

33

Iodine losses during Winkler titrations  

NASA Astrophysics Data System (ADS)

An experiment designed to measure iodine loss during the aliquot version of the Winkler titration for dissolved oxygen in seawater shows that 0.01-0.03 ml l -1 equivalent oxygen is lost at typical oceanic concentrations in the method presently used. A standardization technique, which mimics that employed during the titration of seawater samples, compensates for this iodine loss throughout the oceanic range. This result, contradicting an earlier report by GREEN and CARRITT (1966, Analyst, 91, 207-208), demonstrates that the whole-bottle method of oxygen titration is not to be preferred over the aliquot method.

Knapp, George P.; Stalcup, Marvel C.; Stanley, Robert J.

1991-01-01

34

Adsorption–Photometric Determination of Cationic Surfactant Traces  

Microsoft Academic Search

A procedure has been developed for the adsorption–photometric determination of cationic surfactants in natural water. The procedure is based on the adsorption preconcentration of the cationic surfactants on silica gel, the reaction of the concentrate with the anionic reagent bromothymol blue to form ion pairs on a solid surface, and the photometric determination of excess bromothymol blue in solution. The

A. N. Chebotarev; T. V. Paladenko; T. M. Shcherbakova

2004-01-01

35

Acid Strong Base Titrations Model  

NSDL National Science Digital Library

The Acid Strong Base Titrations model show how to estimate the concentration of the acid in a given sample. If one follows the titration by a visual indicator, the neutralization is detected through a sudden change of that indicator color. This model shows the titration curve as a strong monofunctional base (sodium hydroxide, for example), is added to an aqueous solution of a monoprotic acid. The Acid Strong Base Titrations model was developed using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the jar file will run the program if Java is installed. You can modify this simulation if you have EJS installed by right-clicking within the map and selecting "Open Ejs Model" from the pop-up menu item.

Fernandes, Fernando S.

2012-10-03

36

Effects of Acute and Chronic Cocaine Administration on Titrating-Delay Matching-to-Sample Performance  

ERIC Educational Resources Information Center

The effects of cocaine were examined under a titrating-delay matching-to-sample procedure. In this procedure, the delay between sample stimulus offset and comparison stimuli onset adjusts as a function of the subject's performance. Specifically, matches increase the delay and mismatches decrease the delay. Titrated delay values served as the…

Kangas, Brian D.; Branch, Marc N.

2012-01-01

37

Amperometric, Bipotentiometric, and Coulometric Titration.  

ERIC Educational Resources Information Center

Reviews literature on amperometric, bipotentiometric, and coulometric titration methods examining: apparatus and methodology; acid-base reactions; precipitation and complexing reactions (considering methods involving silver, mercury, EDTA or analogous reagents, and other organic compounds); and oxidation-reduction reactions (considering methods…

Stock, John T.

1984-01-01

38

THE ALHAMBRA PHOTOMETRIC SYSTEM  

SciTech Connect

This paper presents the characterization of the optical range of the ALHAMBRA photometric system, a 20 contiguous, equal-width, medium-band CCD system with wavelength coverage from 3500 A to 9700 A. The photometric description of the system is done by presenting the full response curve as a product of the filters, CCD, and atmospheric transmission curves, and using some first- and second-order moments of this response function. We also introduce the set of standard stars that defines the system, formed by 31 classic spectrophotometric standard stars which have been used in the calibration of other known photometric systems, and 288 stars, flux calibrated homogeneously, from the Next Generation Spectral Library (NGSL). Based on the NGSL, we determine the transformation equations between Sloan Digital Sky Survey ugriz photometry and the ALHAMBRA photometric system, in order to establish some relations between both systems. Finally, we develop and discuss a strategy to calculate the photometric zero points of the different pointings in the ALHAMBRA project.

Villegas, T. Aparicio; Alfaro, E. J.; Cabrera-Cano, J. [Instituto de Astrofisica de Andalucia (CSIC), E-18080, Granada (Spain)], E-mail: terenz@iaa.es, E-mail: emilio@iaa.es (and others)

2010-03-15

39

Titration of an Unknown Acid or Base  

NSDL National Science Digital Library

This website contains a JAVA applet that simulates the titration of an unknown acid or base, and provides a graphical output of the titration curve. The unknown compounds are taken from a list of amino acids. Students set up the parameters of the titration, and then create a simulated pH curve. From this they are able to identify the unknown compound from the list, and determine the acid dissociation constant(s) from the titration data.

Blauch, David N.

2011-02-07

40

Modeling potentiometric titration behavior of glauconite  

Microsoft Academic Search

Potentiometric titration behavior and the effects of dissolution on the titration experiment of a complex natural clay mineral, glauconite, were investigated and interpreted according to surface complexation theory. Considerable dissolution was detected in the time frame of the titration experiments, with the amount of individual cations released from glauconite a function of solution variables and dissolution kinetics. Dissolution effects can

Weiping Lu; Edward H. Smith

1996-01-01

41

Photometric Lunar Surface Reconstruction  

NASA Technical Reports Server (NTRS)

Accurate photometric reconstruction of the Lunar surface is important in the context of upcoming NASA robotic missions to the Moon and in giving a more accurate understanding of the Lunar soil composition. This paper describes a novel approach for joint estimation of Lunar albedo, camera exposure time, and photometric parameters that utilizes an accurate Lunar-Lambertian reflectance model and previously derived Lunar topography of the area visualized during the Apollo missions. The method introduced here is used in creating the largest Lunar albedo map (16% of the Lunar surface) at the resolution of 10 meters/pixel.

Nefian, Ara V.; Alexandrov, Oleg; Morattlo, Zachary; Kim, Taemin; Beyer, Ross A.

2013-01-01

42

Complexometric titration of gallium, indium and thallium(III) using sodium azide as a metal indicator  

Microsoft Academic Search

Summary Thallium(III) has been determined between pH 4.0 and 6.0 by titration against EDTA using sodium azide as indicator. The metal ion gives a bright yellow colour which is discharged at the equivalence point. Micro-quantities upto about 1 mg of the metal have been determined with accuracy. The end-point has also been determined photometrically. Gallium(III) and indium(III) can also be

T. N. Srivastava; N. Singh

1966-01-01

43

Going Beyond, Going Further: The Preparation of Acid-Base Titration Curves.  

ERIC Educational Resources Information Center

Background information, list of materials needed, and procedures used are provided for a simple technique for generating mechanically plotted acid-base titration curves. The method is suitable for second-year high school chemistry students. (JN)

McClendon, Michael

1984-01-01

44

Revised SWIRE photometric redshifts  

NASA Astrophysics Data System (ADS)

We have revised the Spitzer Wide-Area Infrared Extragalactic survey (SWIRE) Photometric Redshift Catalogue to take account of new optical photometry in several of the SWIRE areas, and incorporating Two Micron All Sky Survey (2MASS) and UKIRT Infrared Deep Sky Survey (UKIDSS) near-infrared data. Aperture matching is an important issue for combining near-infrared and optical data, and we have explored a number of methods of doing this. The increased number of photometric bands available for the redshift solution results in improvements both in the rms error and, especially, in the outlier rate. We have also found that incorporating the dust torus emission into the quasi-stellar object (QSO) templates improves the performance for QSO redshift estimation. Our revised redshift catalogue contains over 1 million extragalactic objects, of which 26 288 are QSOs.

Rowan-Robinson, Michael; Gonzalez-Solares, Eduardo; Vaccari, Mattia; Marchetti, Lucia

2013-01-01

45

Direct complexometric titration of calcium phosphates.  

PubMed

Calcium was determined in calcium phosphate samples by dissolving the sample in hydrochloric acid, adding hydroxynaphthol blue indicator and triethanolamine, adjusting the pH to 12.3--12.5 with potassium hydroxide solution, and titrating with standard disodium ethylenediaminetetraacetate solution. Time can be saved and the formation of a precipitate (which dissolves readily during the titration) can be avoided by adding at least 85% of the amount of complexing agent required for titration before adjusting the pH. PMID:903881

Tuckerman, M M; Sanchez de Ramos, M E

1977-09-01

46

UVIS Photometric Zero Points  

NASA Astrophysics Data System (ADS)

This proposal obtains the photometric zero points in 53 of the 62 UVIS/WFC3 filters: the 18 broad-band filters, 8 medium-band filters, 16 narrow-band filters, and 11 of the 20 quad filters {those being used in cycle 17}. The observations will be primary obtained by observing the hot DA white dwarf standards GD153 and G191-B2B. A redder secondary standard, P330E, will be observed in a subset of the filters to provide color corrections. Repeat observations in 16 of the most widely used cycle 17 filters will be obtained once per month for the first three months, and then once every second month for the duration of cycle 17, alternating and depending on target availability. These observations will enable monitoring of the stability of the photometric system. Photometric transformation equations will be calculated by comparing the photometry of stars in two globular clusters, 47 Tuc and NGC 2419, to previous measurements with other telescopes/instruments.;

Kalirai, Jasonjot

2008-07-01

47

Isothermal Titration Calorimetry of RNA  

PubMed Central

Isothermal titration calorimetry (ITC) is a fast and robust method to study the physical basis of molecular interactions. A single well-designed experiment can provide complete thermodynamic characterization of a binding reaction, including Ka, ?G, ?H, ?S and reaction stoichiometry (n). Repeating the experiment at different temperatures allows determination of the heat capacity change (?CP) of the interaction. Modern calorimeters are sensitive enough to probe even weak biological interactions making ITC a very popular method among biochemists. Although ITC has been applied to protein studies for many years, it is becoming widely applicable in RNA biochemistry as well, especially in studies which involve RNA folding and RNA-interactions with small molecules, proteins and with other RNAs. This review focuses on best practices for planning, designing, and executing effective ITC experiments when one or more of the reactants is an RNA.

Salim, Nilshad N.; Feig, Andrew L.

2009-01-01

48

Photometric properties of Mars soils analogs  

USGS Publications Warehouse

We have measured the bidirectional reflectance of analogs of dry, wet, and frozen Martian soils over a wide range of phase angles in the visible spectral range. All samples were produced from two geologic samples: the standard JSC Mars-1 soil simulant and Hawaiian basaltic sand. In a first step, experiments were conducted with the dry samples to investigate the effects of surface texture. Comparisons with results independently obtained by different teams with similar samples showed a satisfying reproducibility of the photometric measurements as well as a noticeable influence of surface textures resulting from different sample preparation procedures. In a second step, water was introduced to produce wet and frozen samples and their photometry investigated. Optical microscope images of the samples provided information about their microtexture. Liquid water, even in relatively low amount, resulted in the disappearance of the backscattering peak and the appearance of a forward-scattering peak whose intensity increases with the amount of water. Specular reflections only appeared when water was present in an amount large enough to allow water to form a film at the surface of the sample. Icy samples showed a wide variability of photometric properties depending on the physical properties of the water ice. We discuss the implications of these measurements in terms of the expected photometric behavior of the Martian surface, from equatorial to circum-polar regions. In particular, we propose some simple photometric criteria to improve the identification of wet and/or icy soils from multiple observations under different geometries.

Pommerol, A.; Thomas, N.; Jost, B.; Beck, P.; Okubo, C.; McEwen, A. S.

2013-01-01

49

Potentiometric titration of calcium in seawater  

NASA Astrophysics Data System (ADS)

By using calcium ion selective electrode (Ca ISE) as indicating electrode, saturated calomel electrode (SCE) as reference electrode and EGTA as titrant, calcium in seawater was determined by potentiometric titration in borate buffer solution. This method can reduce observation errors in the determination of the endpoint, and thus provide better analytical precision (<0.08%) than present complexometric titration.

Xie, Shi-Nan; Ji, Hong; Wu, Ai-Qin; Chen, Guo-Hua

1997-03-01

50

The MUNI Photometric Archive  

NASA Astrophysics Data System (ADS)

In the 1990s of the last century, CCD cameras became more reachable. Due to many advantages of CCD cameras, astronomers began using them as the primary detector for photometry of stellar objects. A typical observatory, which operates one telescope at a time, obtained 0.5 TB of raw data during two decades, that means one million about 500 kB-sized files. There are several observatories in the Czech Republic and Slovakia (taking into account all scientific, public as well as private ones). A rough estimate of the total amount of this photometric data is 10 TB, which could be a very interesting source of observational data. Unfortunately, these data are not available online. These data are stored in observatory archives in arbitrary format. Often it is not even possible to find requested data. We have decided to change this state by establishing a common archive of raw photometric data, which would be available online together with tools for searching, listing etc. We already defined the data format, file and directory structure of our archive. We developed sophisticated tools for archive maintenance as well. Our goal is to provide data storage with simple and straightforward access and we are ready to interconnect with the VO right after the IVOA Photometry Data Model will be released.

Chrastina, Marek; Zejda, Miloslav; Mikulášek, Zden?k

2012-04-01

51

SBR on-line monitoring by set-point titration.  

PubMed

The applicability of set-point titration for monitoring biological processes has been widely demonstrated in the literature. Based on published and on-going experiences, some operating procedures have been specifically developed to be applied to SBRs, so that real-time information about the process and/or the influent can be obtained. This, in turn, would allow plant operators to select the most appropriate actions properly and timely. Five operating modes are described for the monitoring of (1) influent toxicity, (2) influent N-content, (3) nitrification capacity, (4) end of the nitrification reaction, and (5) nitrate effluent concentration, and are currently tested on the on-line titrator TITAAN (TITrimetric Automated ANalyser) which is in operation on a pilot scale SBR. PMID:16722107

Fiocchi, N; Ficara, E; Canziani, R; Luccarini, L; Ciappelloni, F; Ratini, P; Pirani, M; Mariani, S

2006-01-01

52

Accuracy of an Unattended Home CPAP Titration in the Treatment of Obstructive Sleep Apnea  

Microsoft Academic Search

Treatment of sleep apnea-hypopnea syndrome (SAHS) by fixed continuous positive airway pressure (CPAP) requires an in-labora- tory titration procedure to determine the effective pressure level (Peff). We recently reported that one auto-CPAP machine can be used without titration study allowing Peff determination. The aim of this study was to evaluate the accuracy of an auto CPAP trial at home. A

53

On potentiometric titration curves in complexometry.  

PubMed

An equation is given which describes the potential change during complexometric titration of metals with potentiometric end-point detection. The potential of the indicator electrode (e.g., silver or mercury electrode) depends on the equilibrium of the reaction MY + W right harpoon over left harpoon WY + M, where W represents the indicator metal ion, and M the metal ion determined by titration with the ligand Y, forming 1:1 chelates. Introduction of the conditional stability constants and corresponding side-reaction coefficients facilitates the prediction of the limits of application of this type of titration as well as the optimum conditions for the determination. PMID:18960490

Hulanicki, A; Trojanowicz, M

1969-02-01

54

Parametric modeling of photometric signals  

Microsoft Academic Search

This paper studies a new model for photometric signals under high flux assumption. Photometric signals are modeled by Gaussian autoregressive processes having the same mean and variance denoted Constraint Gaussian Autoregressive Processes (CGARP's). The estimation of the CGARP parameters is discussed. The Cramér Rao lower bounds for these parameters are studied and compared to the estimator mean square errors. The

Andre Ferrari; Jean-yves Tourneret; G. Alengrin

2002-01-01

55

Photometric Redshift Calibration for LSST  

Microsoft Academic Search

The proper calibration of photometric redshifts is of the utmost importance for the LSST, as many cosmological measurements depend critically on knowledge of the underlying redshift distribution. We examine how the use of different photometric redshift estimators affect the prediction of the photoz distribution. The great depth of LSST imaging will enable measurements of galaxies over a significant portion of

Samuel Schmidt; J. Newman; J. Tyson; A. Connolly; D. Wittman; D. Matthews; V. Margoniner; A. Choi; I. Udaltsova

2009-01-01

56

ACS photometric Stability  

NASA Astrophysics Data System (ADS)

This program consists of three parts. In the first part we will observe a subset of the ACS white dwarfs with HRC and ACS to verify repeatability to 0.2%, because the filter shifts are based on photometric differences between stars of 1%. These observations are also required to establish relative magnitudes of the primary WD standards at the 0.1% level. Targets should be GD153 and G191B2B, which seems to have the largest V mag error of 0.008 mag. One orbit on the most important filters, including the grism and the prisms, should be expended with each camera for both stars for a total of 4 orbits. In the second part will observe with HRC and WFC a solar analog star, P330E, to estimate any shifts in the short and the long wavelength cutoffs of selected filters. Complete filter bandpasses can be derived directly from the ratio of grism observations with and without the filter in place. The grism is on filter wheel 1, while four filters of interest F330W, F344N, F660N, and F814W are on wheel 2. Each grism observation requires 3 settings: filter alone, filter+grism, and grism alone. In the third part we obtain high S/N photometric and spectroscopic observations of three red stars, VB-8 {M7}, 2M0038+18 {L3.5} and 2M0559-14 {T5} with HRC and WFC to verify the photometry at the new standard position and to obtain accurate calibration {1% or better} of the grism spectra.

Giavalisco, Mauro

2004-07-01

57

Titration Calculations -- A Problem-Solving Approach.  

ERIC Educational Resources Information Center

A problem-solving network (flow chart) constructed for use in calculating titration is described. Points out that use of the network has greatly improved student confidence and skill in performing these calculations. (Author/JN)

Waddling, Robin E. L.

1983-01-01

58

Contributions to the theory of catalytic titrations--I: Complexometric catalytic titrations.  

PubMed

Complexometric catalytic titrations with both volumetric and coulometric addition of the titrant have been simulated. By taking into consideration the equilibrium concentration of the catalyst during the titration, general mathematical equations have been set up. The influence of several factors on the shape of the simulated catalytic titration curve has been investigated and is discussed. The work also deals with the conditions under which the approximate mathematical expressions (equilibrium concentration of the catalyst being neglected) can be applied to simulate the catalytic titration curves with a satisfactory accuracy. PMID:18963705

Gaál, F F; Abramovi?, B F

1984-11-01

59

Photometric stereo endoscopy.  

PubMed

While color video endoscopy has enabled wide-field examination of the gastrointestinal tract, it often misses or incorrectly classifies lesions. Many of these missed lesions exhibit characteristic three-dimensional surface topographies. An endoscopic system that adds topographical measurements to conventional color imagery could therefore increase lesion detection and improve classification accuracy. We introduce photometric stereo endoscopy (PSE), a technique which allows high spatial frequency components of surface topography to be acquired simultaneously with conventional two-dimensional color imagery. We implement this technique in an endoscopic form factor and demonstrate that it can acquire the topography of small features with complex geometries and heterogeneous optical properties. PSE imaging of ex vivo human gastrointestinal tissue shows that surface topography measurements enable differentiation of abnormal shapes from surrounding normal tissue. Together, these results confirm that the topographical measurements can be obtained with relatively simple hardware in an endoscopic form factor, and suggest the potential of PSE to improve lesion detection and classification in gastrointestinal imaging. PMID:23864015

Parot, Vicente; Lim, Daryl; González, Germán; Traverso, Giovanni; Nishioka, Norman S; Vakoc, Benjamin J; Durr, Nicholas J

2013-01-01

60

GTC Photometric Calibration  

NASA Astrophysics Data System (ADS)

We are currently developing the calibration programme for GTC using techniques similar to the ones use for the space telescope calibration (Hammersley et al. 1998, A&AS, 128, 207; Cohen et al. 1999, AJ, 117, 1864). We are planning to produce a catalogue with calibration stars which are suitable for a 10-m telescope. These sources will be not variable, non binary and do not have infrared excesses if they are to be used in the infrared. The GTC science instruments require photometric calibration between 0.35 and 2.5 microns. The instruments are: OSIRIS (Optical System for Imaging low Resolution Integrated Spectroscopy), ELMER and EMIR (Espectrógrafo Multiobjeto Infrarrojo) and the Acquisition and Guiding boxes (Di Césare, Hammersley, & Rodriguez Espinosa 2005, RevMexAA Ser. Conf., 24, 231). The catalogue will consist of 30 star fields distributed in all of North Hemisphere. We will use fields containing sources over the range 12 to 22 magnitude, and spanning a wide range of spectral types (A to M) for the visible and near infrared. In the poster we will show the method used for selecting these fields and we will present the analysis of the data on the first calibration fields observed.

di Cesare, M. A.; Hammersley, P. L.; Rodriguez Espinosa, J. M.

2006-06-01

61

Tentative Method for the Calibration of Nitric Oxide, Nitrogen Dioxide, and Ozone Analyzers by Gas Phase Titration.  

National Technical Information Service (NTIS)

A detailed procedural description of a technique for the dynamic calibration of ambient air monitors for ozone, nitric oxide, and nitrogen dioxide is presented. A gas phase titration technique utilizing the rapid gas phase reaction between nitric oxide an...

K. A. Rehme B. E. Martin J. A. Hodgeson

1974-01-01

62

Monitoring assembly of ribonucleoprotein complexes by isothermal titration calorimetry  

PubMed Central

Isothermal titration calorimetry (ITC) is a useful technique to study RNA-protein interactions, as it provides the only method by which the thermodynamic parameters of free energy, enthalpy, and entropy can be directly determined. This chapter presents a general procedure for studying RNA-protein interactions using ITC, and gives specific examples for monitoring the binding of Caenorhabditis elegans GLD-1 STAR domain to TGE RNA and the binding of Aquifex aeolicus S6:S18 ribosomal protein heterodimer to an S15-rRNA complex.

Recht, Michael I.; Ryder, Sean P.; Williamson, James R.

2010-01-01

63

Calibrating photometric redshifts of luminous red galaxies  

Microsoft Academic Search

We discuss the construction of a photometric redshift catalogue of luminous red galaxies (LRGs) from the Sloan Digital Sky Survey (SDSS), emphasizing the principal steps necessary for constructing such a catalogue: (i) photometrically selecting the sample, (ii) measuring photometric redshifts and their error distributions, and (iii) estimating the true redshift distribution. We compare two photometric redshift algorithms for these data

Nikhil Padmanabhan; Tamás Budavári; David J. Schlegel; Terry Bridges; Jonathan Brinkmann; Russell Cannon; Andrew J. Connolly; Scott M. Croom; István Csabai; Michael Drinkwater; Daniel J. Eisenstein; Paul C. Hewett; Jon Loveday; Kevin A. Pimbblet; Roberto De Propris; Donald P. Schneider; Ryan Scranton; Uros Seljak; Tom Shanks; István Szapudi; Alexander S. Szalay; David Wake

2005-01-01

64

AMPEROMETRIC TITRATION OF THORIUM IN MONAZITE SANDS  

Microsoft Academic Search

A practical method for the separation and amperometric determination of ; thorium in monazite sands is proposed. The attack is carried out with sulfuric ; acid on 10-gram samples; thorium and the rare earths are separated by a single ; precipitation with oxalic acid, and the final amperometric titration is made with ; ammonium paramolybdate as titrant. The composition of

J. J. Burastero; R. W. Martres

1962-01-01

65

Isothermal Titration Calorimetry in the Student Laboratory  

ERIC Educational Resources Information Center

Isothermal titration calorimetry (ITC) is the measurement of the heat produced by the stepwise addition of one substance to another. It is a common experimental technique, for example, in pharmaceutical science, to measure equilibrium constants and reaction enthalpies. We describe a stirring device and an injection pump that can be used with a…

Wadso, Lars; Li, Yujing; Li, Xi

2011-01-01

66

Novel approaches to analysis by flow injection gradient titration.  

PubMed

Two novel procedures for flow injection gradient titration with the use of a single stock standard solution are proposed. In the multi-point single-line (MP-SL) method the calibration graph is constructed on the basis of a set of standard solutions, which are generated in a standard reservoir and subsequently injected into the titrant. According to the single-point multi-line (SP-ML) procedure the standard solution and a sample are injected into the titrant stream from four loops of different capacities, hence four calibration graphs are able to be constructed and the analytical result is calculated on the basis of a generalized slope of these graphs. Both approaches have been tested on the example of spectrophotometric acid-base titration of hydrochloric and acetic acids with using bromothymol blue and phenolphthalein as indicators, respectively, and sodium hydroxide as a titrant. Under optimized experimental conditions the analytical results of precision less than 1.8 and 2.5% (RSD) and of accuracy less than 3.0 and 5.4% (relative error (RE)) were obtained for MP-SL and SP-ML procedures, respectively, in ranges of 0.0031-0.0631 mol L(-1) for samples of hydrochloric acid and of 0.1680-1.7600 mol L(-1) for samples of acetic acid. The feasibility of both methods was illustrated by applying them to the total acidity determination in vinegar samples with precision lower than 0.5 and 2.9% (RSD) for MP-SL and SP-ML procedures, respectively. PMID:17903467

Wójtowicz, Marzena; Kozak, Joanna; Ko?cielniak, Pawe?

2007-09-26

67

Modification of a pH-Titration Standardization Method for Formaldehyde  

Microsoft Academic Search

Procedures for monitoring formaldehyde concentration in air ultimately require a standard solution with which to calibrate the response of the analytical method. Although formaldehyde solutions of nominal concentration may be prepared from a variety of sources, the solutions must be standardized. The sulfite-pH\\/ titration method was tested and found to give erratic results. This paper presents evidence to indicate that

Reimar R. W. Gaertner

1988-01-01

68

Coulometric Titration of Ethylenediaminetetraacetate (EDTA) with Spectrophotometric Endpoint Detection: An Experiment for the Instrumental Analysis Laboratory  

ERIC Educational Resources Information Center

Ethylenediaminetetraacetate (EDTA) is commonly used as an anticoagulant in blood-collection procedures. In this experiment for the instrumental analysis laboratory, students determine the quantity of EDTA in commercial collection tubes by coulometric titration with electrolytically generated Cu[superscript 2+]. The endpoint is detected…

Williams, Kathryn R.; Young, Vaneica Y.; Killian, Benjamin J.

2011-01-01

69

Titration curves in complexometric titrations with the redox system Fe(III)/Fe(II).  

PubMed

Potentiometric titrations of metal ions with EDTA have been carried out with a platinum or graphite electrode and the Fe(III)/Fe(II) redox system. In the absence of oxygen and for pH < 2 the titration curves may be described by an equation similar to that given previously for titrations with silver and mercury electrodes. Titration curves for bismuth and indium, which are more strongly complexed than iron, are asymmetrical and useful for analytical purposes. When the titrated ions are complexed less strongly than iron(III) ions the kinetics of metal complexation have a pronounced effect. The titration curves of thorium and copper, which react more rapidly than iron, are analytically useful. The curves recorded rapidly after titrant additions have a better end-point break than those which correspond to thermodynamic equilibrium. When a metal, e.g., nickel, is weakly bound by EDTA, and reacts more slowly than iron, a very small end-point break or none at all is observed. PMID:18960880

Hulanicki, A; Karwowska, R

1971-03-01

70

Photometric Study of Selected Asteroids  

NASA Astrophysics Data System (ADS)

We performed photometric observations for eleven asteroids. New rotation periods were determined for five asteroids: 2812 Scaltriti (7.596 h), 4716 Urey (6.2 h), 7446 Hadrianus (3.402 h), (26657) 2000 SX293 (2.8 - 3.8 h), and (54063) 2000 GC136 (5.154 h).

Shevchenko, Vasilij G.; Velichko, Feodor P.; Checha, Vitaly A.; Krugly, Yurij N.

2014-07-01

71

Can Selforganizing Maps Accurately Predict Photometric Redshifts.  

National Technical Information Service (NTIS)

We present an unsupervised machine-learning approach that can be employed for estimating photometric redshifts. The proposed method is based on a vector quantization called the self-organizing-map (SOM) approach. A variety of photometrically derived input...

C. Klose M. J. Way

2012-01-01

72

A Theoretical Photometric Function of Saturn'S Rings.  

National Technical Information Service (NTIS)

A photometric theory of Saturn's rings is developed assuming that partially elastic collisions have brought all ring particles to the same plane. The resulting photometric function explains the tilt effect of the rings, but the opposition peak must origin...

K. A. Haemeen-anttila P. Vaaraniemi

1974-01-01

73

Graphical evaluation of complexometric titration curves.  

PubMed

A graphical method, based on logarithmic concentration diagrams, for construction, without any calculations, of complexometric titration curves is examined. The titration curves obtained for different kinds of unidentate, bidentate and quadridentate ligands clearly show why only chelating ligands are usually used in titrimetric analysis. The method has also been applied to two practical cases where unidentate ligands are used: (a) the complexometric determination of mercury(II) with halides and (b) the determination of cyanide with silver, which involves both a complexation and a precipitation system; for this purpose construction of the diagrams for the HgCl(2)/HgCl(+)/Hg(2+) and Ag(CN)(2)(-)/AgCN/CN(-) systems is considered in detail. PMID:18963841

Guinon, J L

1985-04-01

74

Coulometrische titration von hypochloriten und chloraten.  

PubMed

Hypochlorite was determined by direct coulometric titration with iron(II) in an acetate buffered solution. Chlorate was titrated with titanium(III) in 2M hydrochloric acid. Amperometric indication with one and two electrodes, respectively, was used. Mixtures of hypochlorites and chlorates, e.g., in industrial electrolytes, may be analysed. On a déterminé l'hypochlorite par titrage coulométrique direct avec le fer(II) dans une solution tamponnée à l'acétate. On a titré le chlorate avec le titane(III) en acide chlorhydrique 2M. On a utilisé l'indication ampérométrique une et deux électrodes respectivement. On peut analyser des mélanges d'hypochlorites et de chlorates, par exemple dans des électrolytes industriels. PMID:18960728

Gründler, P; Holzapfel, H

1970-03-01

75

Potentiometric titration of free acid in uranium solutions.  

National Technical Information Service (NTIS)

Hydrolysis properties of metal cations and fundamental principles of the potentiometric titration of free acid in aqueous solutions containing metal cations were described. The published papers and reports for the alkalimetric and acidimetric titration of...

M. Suh W. Kim J. Kim S. Sohn T. Eom

1998-01-01

76

[Estimation of sulfhydryl groups by laboratory titrator T-201].  

PubMed

A method for estimating sulfhydryl groups by laboratory titrator T-201 is proposed. It consists in culonometric titration of SH-groups by silver ions. The method is highly sensitive and reproducible. PMID:7378573

Aleksidze, N G; Koshoridze, N I

1980-01-01

77

PHOTOMETRIC REDSHIFTS OF SUBMILLIMETER GALAXIES  

SciTech Connect

We use the photometric redshift method of Chakrabarti and McKee to infer photometric redshifts of submillimeter galaxies with far-IR (FIR) Herschel data obtained as part of the PACS Evolutionary Probe program. For the sample with spectroscopic redshifts, we demonstrate the validity of this method over a large range of redshifts (4 {approx}> z {approx}> 0.3) and luminosities, finding an average accuracy in (1 + z{sub phot})/(1 + z{sub spec}) of 10%. Thus, this method is more accurate than other FIR photometric redshift methods. This method is different from typical FIR photometric methods in deriving redshifts from the light-to-gas mass (L/M) ratio of infrared-bright galaxies inferred from the FIR spectral energy distribution, rather than dust temperatures. To assess the dependence of our photometric redshift method on the data in this sample, we contrast the average accuracy of our method when we use PACS data, versus SPIRE data, versus both PACS and SPIRE data. We also discuss potential selection effects that may affect the Herschel sample. Once the redshift is derived, we can determine physical properties of infrared-bright galaxies, including the temperature variation within the dust envelope, luminosity, mass, and surface density. We use data from the GOODS-S field to calculate the star formation rate density (SFRD) of submillimeter bright sources detected by AzTEC and PACS. The AzTEC-PACS sources, which have a threshold 850 {mu}m flux {approx}> 5 mJy, contribute 15% of the SFRD from all ultraluminous infrared galaxies (L{sub IR} {approx}> 10{sup 12} L{sub Sun }), and 3% of the total SFRD at z {approx} 2.

Chakrabarti, Sukanya [School of Physics and Astronomy, Rochester Institute of Technology, 84 Lomb Memorial Drive, Rochester, NY 14623 (United States); Magnelli, Benjamin; Lutz, Dieter; Berta, Stefano; Popesso, Paola [Max-Planck-Institut fuer Extraterrestrische Physik, Postfach 1312, Giessenbachstrasse 1, D-85741 Garching (Germany); McKee, Christopher F. [Physics and Astronomy Departments, UC Berkeley, Berkeley, CA 94720 (United States); Pozzi, Francesca, E-mail: chakrabarti@astro.rit.edu [Dipartimento di Astronomia, Universita degli Studi di Bologna, Via Ranzani 1, I-40127 Bologna (Italy)

2013-08-20

78

Photometric Redshifts from Reconstructed Quasar Templates  

Microsoft Academic Search

From Sloan Digital Sky Survey (SDSS) commissioning photometric and spectroscopic data, we investigate the utility of photometric redshift techniques in the task of estimating QSO redshifts. We consider empirical methods (e.g., nearest neighbor searches and polynomial fitting), standard spectral template fitting, and hybrid approaches (i.e., training spectral templates from spectroscopic and photometric observations of QSOs). We find that in all

Tamás Budavári; István Csabai; Alexander S. Szalay; Andrew J. Connolly; Gyula P. Szokoly; Daniel E. Vanden Berk; Gordon T. Richards; Michael A. Weinstein; Donald P. Schneider; Narciso Benítez; Tamás Budavári; Robert Brunner; Patrick B. Hall; Zeljko Ivezic; Péter Z. Kunszt; Jeffrey R. Pier; Donald G. York

2001-01-01

79

Simple and Automated Coulometric Titration of Acid Using Nonisolated Electrodes  

ERIC Educational Resources Information Center

Coulometric titrations involve the quantification of analyte by measurements of current and time. In most coulometric titrations, the anode and cathode are placed in isolated cells that are connected by a salt bridge. By contrast, the experiments described here involve coulometric titrations (of acidic protons in solution) using a silver anode and…

Kuntzleman, Thomas S.; Kenney, Joshua B.; Hasbrouck, Scott; Collins, Michael J.; Amend, John R.

2011-01-01

80

Amperometric complex-formation titration of traces of thorium.  

PubMed

Thorium has been determined in the microgram range by complexometric titration with EDTA. The end-point was detected by following the anodic wave of EDTA at a rotating mercury electrode. It has been shown that thorium can be titrated in the presence of large amounts of other metals. Following electrolysis at a mercury pool electrode the titration is selective for thorium. PMID:18960984

Freese, F; Oostervink, R; Den Boef, G

1971-10-01

81

Photometric Variability of Y Dwarfs  

NASA Astrophysics Data System (ADS)

Condensate clouds are present in brown dwarf atmospheres due to their low surface temperatures. As the coolest (Teff < 600 K) class of brown dwarfs currently known, Y dwarfs allow us to study the unique atmospheric physics that occur at these temperatures including the formation of sulfide, chloride, and water clouds. Dynamic inhomogeneities in cloud cover should manifest as photometric variabilities in the observed light curves of brown dwarfs. This phenomenon was originally documented in two brown-dwarfs by Morales-Calderón et al. (2006) at 4.5 microns, and in one brown dwarf by Heinze et al. (2013) at 3.6 microns. We describe our ongoing program to monitor fourteen Y dwarfs for photometric variability at 3.6 and 4.5 microns with the Spitzer Space Telescope and present initial results including the first detection of Y dwarf variability.

Trucks, Jesica; Cushing, M.; Hardegree-Ullman, K.; Gelino, C. R.; Kirkpatrick, J. D.; Mace, G. N.; Gizis, J.; Marley, M. S.; Morley, C.; Fortney, J. J.

2014-01-01

82

Photometric modeling of Saturn's rings  

Microsoft Academic Search

The scattering properties of particulate rings with volume filling factors in the interval D=0.001–0.3 are studied, with photometric Monte Carlo ray tracing simulations combining the advantages of direct (photons followed from the source) and indirect methods (brightness as seen from the observing direction). Besides vertically homogeneous models, ranging from monolayers to classical many-particle thick rings, particle distributions obtained from dynamical

Heikki Salo; Raine Karjalainen

2003-01-01

83

Color Subspaces as Photometric Invariants  

Microsoft Academic Search

Complex reflectance phenomena such as specular reflections confound many vision problems since they produce image ‘features’\\u000a that do not correspond directly to intrinsic surface properties such as shape and spectral reflectance. A common approach\\u000a to mitigate these effects is to explore functions of an image that are invariant to these photometric events. In this paper\\u000a we describe a class of

Todd Zickler; Satya P. Mallick; David J. Kriegman; Peter N. Belhumeur

2008-01-01

84

Modeling complexometric titrations of natural water samples.  

PubMed

Complexometric titrations are the primary source of metal speciation data for aquatic systems, yet their interpretation in waters containing humic and fulvic acids remains problematic. In particular, the accuracy of inferred ambient free metal ion concentrations and parameters quantifying metal complexation by natural ligands has been challenged because of the difficulties inherent in calibrating common analytical methods and in modeling the diverse array of ligands present. This work tests and applies a new method of modeling titration data that combines calibration of analytical sensitivity (S) and estimation of concentrations and stability constants for discrete natural ligand classes ([Li]T and Ki) into a single step using nonlinear regression and a new analytical solution to the one-metal/two-ligand equilibrium problem. When applied to jointly model data from multiple titrations conducted at different analytical windows, it yields accurate estimates of S, [Li]T, Ki, and [Cu2+] plus Monte Carlo-based estimates of the uncertainty in [Cu2+]. Jointly modeling titration data at low-and high-analytical windows leads to an efficient adaptation of the recently proposed "overload" approach to calibrating ACSV/CLE measurements. Application of the method to published data sets yields model results with greater accuracy and precision than originally obtained. The discrete ligand-class model is also re-parametrized, using humic and fulvic acids, L1 class (K1 = 10(13) M(-1)), and strong ligands (L(S)) with K(S) > K1 as "natural components". This approach suggests that Cu complexation in NW Mediterranean Sea water can be well represented as 0.8 +/- 0.3/0.2 mg humic equiv/L, 13 +/- 1 nM L1, and 2.5 +/- 0.1 nM L(S) with [CU]T = 3 nM. In coastal seawater from Narragansett Bay, RI, Cu speciation can be modeled as 0.6 +/- 0.1 mg humic equiv/L and 22 +/- 1 nM L1 or approximately 12 nM L1 and approximately 9 nM L(S), with [CU]T = 13 nM. In both waters, the large excess (approximately 10 nM) of high-affinity, Cu-binding ligands over [CU]T results in low equilibrium [Cu2+] of 10(-14.5 +/- 0.2) M and 10(-13.3 +/- 0.4) M, respectively. PMID:12731837

Hudson, Robert J M; Rue, Eden L; Bruland, Kenneth W

2003-04-15

85

Combining automatic titration of total iron and sulfur in thermal battery materials  

NASA Astrophysics Data System (ADS)

Optimal thermal battery performance requires careful control of the iron disulfide content in the catholyte mixture. Previously, the iron and sulfur content of battery materials was determined separately, each requiring a lengthy sample preparation and clean up procedure. A new method has been developed which allows both determinations to be made on the same sample following a simple dissolution procedure. Sample preparation requires oxidation and dissolution with nitric acid followed by dissolution in hydrochloric acid. Iron and sulfur are then determined on sample aliquots by automatic titration. The implementation of this combined procedure for the determination of iron and sulfur by automatic titration has resulted in a substantial reduction in the analysis time. Since sample aliquots are used for each determination, the need to repeat a sample for analysis is rare, improving both the analytical efficiency and sample throughput. Results obtained for sulfur show an improved precision.

Marley, N. A.

1986-05-01

86

Stepwise injection photometric determination of mercaptanes in air  

Microsoft Academic Search

An automated procedure is developed for the photometric determination of mercaptanes in air. To achieve the required selectivity\\u000a of analyte determination, a scheme of sample preparation was elaborated, which includes the liquid absorption separation of\\u000a interfering components (hydrogen sulfide and sulfur dioxide) and mercaptanes on two consequent chromatography columns with\\u000a glass wool impregnated with a zinc acetate solution and an

A. V. Bulatov; E. A. Slavina; L. N. Moskvin

2010-01-01

87

A "release" protocol for isothermal titration calorimetry.  

PubMed Central

Isothermal titration calorimetry (ITC) has become a standard method for investigating the binding of ligands to receptor molecules or the partitioning of solutes between water and lipid vesicles. Accordingly, solutes are mixed with membranes (or ligands with receptors), and the subsequent heats of incorporation (or binding) are measured. In this paper we derive a general formula for modeling ITC titration heats in both binding and partitioning systems that allows for the modeling of the classic incorporation or binding protocols, as well as of new protocols assessing the release of solute from previously solute-loaded vesicles (or the dissociation of ligand/receptor complexes) upon dilution. One major advantage of a simultaneous application of the incorporation/binding and release protocols is that it allows for the determination of whether a ligand is able to access the vesicle interior within the time scale of the ITC experiment. This information cannot be obtained from a classical partitioning experiment, but it must be known to determine the partition coefficient (or binding constant and stochiometry) and the transfer enthalpy. The approach is presented using the partitioning of the nonionic detergent C12EO7 to palmitoyloleoylphosphatidylcholine vesicles. The release protocol could also be advantageous in the case of receptors that are more stable in the ligand-saturated rather than the ligand-depleted state.

Heerklotz, H H; Binder, H; Epand, R M

1999-01-01

88

Flow-injection photometric determination of mercaptans in light oil products with chromatomembrane extraction  

Microsoft Academic Search

A procedure was developed for the flow-injection photometric determination of mercaptans in light oil products. The use of\\u000a sodium nitroferricyanide as the photometric reagent at 540 nm provides a detection limit of mercaptan sulfur of 0.3 mg\\/L at\\u000a a volume of the sample of 3 mL; the analytical range is from 1 to 50 mg\\/L.

A. V. Bulatov; D. V. Goncharova; L. N. Moskvin

2006-01-01

89

Photometric monitoring of bright supernovae  

NASA Astrophysics Data System (ADS)

The program of CCD photometric monitoring of bright supernovae (SNe) is carried out at 0.4 — 1.0 meter telescopes of the Sternberg Astronomical Institute, Crimean Astrophysical Observatory and Stará Lesná Observatory since 1998. We have observed more than 250 SNe of different types. We present the results of observations of SNe Ia 2003du, 2009nr and 2011fe, type IIb SNe 2008ax, 2011dh, type II SNe 2004ek and 2005kd and discuss physical parameters of the explosions. %

Tsvetkov, D. Yu.; Pavlyuk, N. N.; Volkov, I. M.; Shugarov, S. Yu.

2014-03-01

90

Photometric redshifts from reconstructed QSO templates  

Microsoft Academic Search

From SDSS commissioning photometric and spectroscopic data, we investigate\\u000athe utility of photometric redshift techniques to the task of estimating QSO\\u000aredshifts. We consider empirical methods (e.g. nearest-neighbor searches and\\u000apolynomial fitting), standard spectral template fitting and hybrid approaches\\u000a(i.e. training spectral templates from spectroscopic and photometric\\u000aobservations of QSOs). We find that in all cases, due to the presence

Tamas Budavari; Istvan Csabai; Alexander S. Szalay; Andrew J. Connolly; Gyula P. Szokoly

2001-01-01

91

Calibrating Photometric Redshifts of Luminous Red Galaxies  

Microsoft Academic Search

We discuss the construction of a photometric redshift catalogue of Luminous\\u000aRed Galaxies (LRGs) from the Sloan Digital Sky Survey (SDSS), emphasizing the\\u000aprincipal steps necessary for constructing such a catalogue -- (i)\\u000aphotometrically selecting the sample, (ii) measuring photometric redshifts and\\u000atheir error distributions, (iii) and estimating the true redshift distribution.\\u000aWe compare two photometric redshift algorithms for these

Nikhil Padmanabhan; Tamas Budavari; David J. Schlegel; Terry Bridges; Jonathan Brinkmann; Russell Cannon; Andrew J. Connolly; Scott M. Croom; Istvan Csabai; Michael Drinkwater; Daniel J. Eisenstein; Paul C. Hewett; Jon Loveday; Robert C. Nichol; Kevin A. Pimbblet; Roberto De Propris; Donald P. Schneider; Ryan Scranton; Uros Seljak; Tom Shanks; Istvan Szapudi; Alexander S. Szalay; David Wake

2004-01-01

92

Photometric Detection of Extra-Solar Planets  

NASA Technical Reports Server (NTRS)

This NASA Origins Program grant supported the TEMPEST Texas McDonald Photometric Extrasolar Search for Transits) program at McDonald Observatory, which searches for transits of extrasolar planets across the disks of their parent stars. The basic approach is to use a wide-field ground-based telescope (in our case the McDonald Observatory 0.76m telescope and it s Prime Focus Corrector) to search for transits of short period (1-15 day orbits) of close-in hot-Jupiter planets in orbit around a large sample of field stars. The next task is to search these data streams for possible transit events. We collected our first set of test data for this program using the 0.76 m PFC in the summer of 1998. From those data, we developed the optimal observing procedures, including tailoring the stellar density, exposure times, and filters to best-suit the instrument and project. In the summer of 1999, we obtained the first partial season of data on a dedicated field in the constellation Cygnus. These data were used to develop and refine the reduction and analysis procedures to produce high-precision photometry and search for transits in the resulting light curves. The TeMPEST project subsequently obtained three full seasons of data on six different fields using the McDonald Observatory 0.76m PFC.

Hatzes, Artie P.; Cochran, William D.

2004-01-01

93

Amperometric complex-formation titration of traces of alkaline earths.  

PubMed

Alkaline earth metals were determined in microgram quantities by complexometric titration with EDTA, EGTA and DTPA. The end-point was detected by following the anodic wave of the chelating agent at the rotating mercury electrode. All the alkaline earths can be titrated at the microgram level with reasonable accuracy, and calcium may be titrated with EGTA in the presence of a 1000-fold excess of magnesium. PMID:18960827

den Boef, G; Freese, F; Kramer, M M; Poppe, H

1970-10-01

94

Generalized theory for two- phase ion- pair and complexometric titrations  

Microsoft Academic Search

A systematic theoretical treatment of the two-phase titration based on ion-pair and metal-complex formation is presented. Equations for the titration curve, accuracy, equivalence point and choice of the indicator are derived. Much attention is paid to the parameters determining the ‘titratability’viz. extraction constant, distribution constant, phase volume ratio and the concentration of the analyte. Special attention is given to the

A. Bult; H. A. Dingjan; S. M. Dreijer-van der Glas; W. P. Van Bennekom

1985-01-01

95

Automated titration method for use on blended asphalts  

SciTech Connect

A system for determining parameters and compatibility of a substance such as an asphalt or other petroleum substance uses titration to highly accurately determine one or more flocculation occurrences and is especially applicable to the determination or use of Heithaus parameters and optimal mixing of various asphalt stocks. In a preferred embodiment, automated titration in an oxygen gas exclusive system and further using spectrophotometric analysis (2-8) of solution turbidity is presented. A reversible titration technique enabling in-situ titration measurement of various solution concentrations is also presented.

Pauli, Adam T. (Cheyenne, WY); Robertson, Raymond E. (Laramie, WY); Branthaver, Jan F. (Chatham, IL); Schabron, John F. (Laramie, WY)

2012-08-07

96

Systemic Errors In Quantitative PCR Titration of Self-Complementary AAV Vectors and Improved Alternative Methods  

PubMed Central

Self-complementary AAV (scAAV) vector genomes contain a covalently closed hairpin derived from a mutated inverted terminal repeat which connects the two monomer single stranded genomes into a head-to-head or tail-to-tail dimer. We found that during quantitative PCR (qPCR) this structure inhibits the amplification of proximal amplicons and causes the systemic underreporting of copy number by as much as 10-fold. We show that cleavage of scAAV vector genomes with restriction endonuclease to liberate amplicons from the covalently closed terminal hairpin restores quantitative amplification, and we implement this procedure in a simple, modified qPCR titration method for scAAV vectors. Additionally, we developed and present an AAV genome titration procedure based on gel electrophoresis that requires minimal sample processing and has very low inter assay variability, and as such is well suited for the rigorous quality control demands of clinical vector production facilities.

Fagone, Paolo; Wright, J. Fraser; Nathwani, Amit C.; Nienhuis, Arthur W.; Davidoff, Andrew M.; Gray, John T.

2013-01-01

97

Generalized theory for two-phase ion-pair and complexometric titrations. II. Two-phase titrations with side reactions.  

PubMed

For the two-phase titration based on ion-pair and metal-complex formation full attention is given to side reactions in both phases. Their significance for the applicability of this type of titration is evaluated. Side reactions in the aqueous phase diminish and in the organic phase promote the 'titratability'. Equations for the calculation of the side reaction coefficients, the titration curve and the selection of the optimal pH and minimal side reaction interference (in the aqueous phase) are presented. Finally a full description is given of the two-phase titration including all parameters determining the 'titratability'. The merits of the developed theory are illustrated by literature examples. PMID:4080512

Bult, A; Dingjan, H A; Dreijer-van der Glas, S M; Van Bennekom, W P

1985-12-13

98

The LYRA photometric system and the catalog of photometric reference standard stars  

NASA Astrophysics Data System (ADS)

The 10-color photometric system for the Russian space photometric experiment LYRA is described. It is shown that the system is effective for the determination of interstellar extinction, separation of supergiants, and evaluation of metallicity. The creation of a large grid of high-precision photometric standards is one of the most important tasks of the LYRA experiment.

Zakharov, A. I.; Mironov, A. V.; Nikolaev, F. N.; Prokhorov, M. E.; Tuchin photometric system, M. S.; standard star catalog, the

2013-10-01

99

[Determination of the sulfate ion content in antibiotic sulfate salts by a complexometric titration method].  

PubMed

A possibility of assaying antibiotic sulfates, such as gentamicin, kanamycin, monomycin, neomycin, ristomycin, streptomycin, florimycin and polymyxin M sulfates for sulfate ions by titration with barium chloride in the presence of chlorphosphonaso-III, a metal indicator immediately in the salt solutions or after elimination of the cation by means of ion exchange (sulfocation exchange resins in H+-form) was tested. The procedure was shown to be adequate to the classical weight method. PMID:7469396

Kartseva, V D; Lokshin, G B; Libinson, G S; Kruzhkova, N G

1980-12-01

100

Simultaneous multiple injection to perform titration and standard addition in mono-segmented flow analysis.  

PubMed

An automated system to perform titration and standard addition in monosegemented flow analysis by employing the simultaneous multiple injection is described. The system was controlled by aPC-AT-386 microcomputer through a home-made parallel interface, employing a diode array spectrophotometer as detector. Software was written in QuickBasic 4.5 to control the system and for data acquisition. A three-way solenoid valve was used in conjunction with a proportional injector to add the titrant solution or the standard solution to the sample, to carry out titration or standard addition, respectively. Only one standard solution was used in each procedure and different quantities of titrant or standard were added to the sample by controlling the time interval in which the solenoid valve was switched on. Titration and standard addition curves similar to those of the manual methods were obtained in both cases, since the sample dispersion was very low due to the air bubbles of the monosegment. The titration system was evaluated through the determination of Fe(II) with a KMnO4 standard solution in pharmaceutical preparations. The standard addition process was assessed by determining Cr(VI) in natural waters and domestic wastewater using the diphenylcarbazide method. The results obtained in both methodologies did not differ significantly from the reference methods at a 95% confidence level. PMID:18924880

Assali, M; Raimundo, I M; Facchin, I

2001-01-01

101

Continuous on-line feedback based flow titrations. Complexometric titrations of calcium and magnesium.  

PubMed

The methodology of continuous feedback-based flow titrations and the principle of compensating errors [Anal. Chem. 72 (2000) 4713; Anal. Chim. Acta 435 (2001) 289] were applied to the determination of calcium and magnesium ions with EDTA. The flow of the titrant, EDTA, varied linearly in response to a controller output voltage while the total flow (F(T), the sum of the metal ion sample flow and the titrant flow) was held constant. The sample was pre-doped with a metal ion indicator; the status of the indicator color in the mixed stream was monitored by an optical detector and was used for governing the controller output as well as for interpreting the results of the titrations. The titrant flow initially ramped upward linearly. As a change in the color corresponding to the equivalence point was sensed by the detector, the controller output (instantaneous value V(H)) reversed its ramp direction, thus decreasing the titrant flow linearly at the same ramp rate. When the predefined absorbance corresponding to the equivalence point was sensed again, the controller voltage (instantaneous value V(L)) was ramped in reverse once more, going upward. Because of the lag time between a change in the controller output and its effect being sensed by the detector, the controller voltage corresponding to the actual equivalence point was the average of V(H) and V(L). Continuous sensor-governed operation of the controller resulted in a triangular waveform. The mean of this waveform during any cycle gives the equivalence point controller voltage V(E). This principle allowed true titrations with good reproducibility (0.2-0.7% R.S.D.) and throughput (33-42 s per titration). PMID:18969033

Jo, Kyoo Dong; Dasgupta, Purnendu K

2003-05-28

102

A photometric study of the Orion OB 1 association. 2: Photometric analysis  

NASA Technical Reports Server (NTRS)

The procedures adopted for analysis of photometric data in terms of color excesses, intrinsic color indexes, absolute visual magnitudes, and rotational-velocity effects are discussed in detail for Orion association B-, intermediate (I)-, and AF-type stars. The effects of the nebular environment and a comparison of various calibrations of Balmer-line and four-color indexes are considered for the determination of individual absolute magnitudes for B-type stars. When absolute magnitudes of stars in the region of the Orion Nebula are determined from the beta index, emission mechanisms appear to spuriously brighten them. A detailed comparison of absolute magnitudes derived from Balmer-line indexes and MK spectral-type calibrations is presented. The data are also examined with regard to the effects of polarization and infrared excesses. The results suggest a complex combination of intracluster and circumstellar origins for these processes.

Warren, W. H., Jr.; Hesser, J. E.

1976-01-01

103

APIRP: The Automated Photometric Data Reduction Package  

NASA Astrophysics Data System (ADS)

For decades the Image Reduction and Analysis Facility (IRAF) has been the standard for processing CCD-based image datasets. During that time, technology has advanced and the astronomical record greatly expanded. However, the discovery process is often bogged down by the time consuming procedures of image reduction. To keep up with demand and shorten reduction steps programmers have developed a series of command languages (CL) for IRAF and most recently, within only the past five years, the Python-based language, Pyraf. Python is a robust and powerful language that combines syntactical simplicity with versatile and dynamic file management, database access and software development capabilities, to name just a few features. Pyraf, by extension, incorporates all of the qualities of IRAF CL, with all of the power and flexibility provided by Python. Pyraf scripts may be written to automate file processing at the same time that reduction tasks are called from IRAF. Thus, the potential to write fully automated reduction procedures is here; tightening the gaps of scientific advancement. We have created such a tool for CCD Photometry. Our Automated Photometric Image Reduction Package (APIRP) uses a range of graphical user interfaces (GUI's) to form an interactive yet non-overbearing user environment. A combination of built-in file management and procedural variability makes APIRP a perfect choice for both amateur and professional astronomers. Due to the programs design, it can be run from anywhere on your computer and users can specify exactly what steps of reduction they wish to execute. Thus, setup is easy with no need for cumbersome documentation and tasks may be preformed piecewise or in blocks, depending on the users needs.

Hebert, Ian; Ziffer, J.; Walker, M.

2009-09-01

104

A Blind Test of Photometric Redshift Prediction  

Microsoft Academic Search

Results of a blind test of photometric redshift predictions against spectroscopic galaxy redshifts obtained in the Hubble Deep Field with the Keck Telescope are presented. The best photometric redshift schemes predict spectroscopic redshifts with a redshift accuracy of Deltaz < 0.1 for more than 68% of sources and with Deltaz < 0.3 for 100%, when single-feature spectroscopic redshifts are removed

David W. Hogg; Judith G. Cohen; Roger Blandford; Stephen D. J. Gwyn; F. D. A. Hartwick; B. Mobasher; Paula Mazzei; Marcin Sawicki; Huan Lin; H. K. C. Yee; Andrew J. Connolly; Robert J. Brunner; Istvan Csabai; Mark Dickinson; Mark U. Subbarao; Alexander S. Szalay; Alberto Fernández-Soto; Kenneth M. Lanzetta; Amos Yahil

1998-01-01

105

Photometric calibration of a radiochromic gel dosimeter  

NASA Astrophysics Data System (ADS)

Measurement traceability of dosimetry systems to standards of measurement underpins reliable radiation treatments. A method to determine the product of the molar linear absorption coefficient and the radiation chemical yield is presented, which provides a means of photometric calibration of chemical dosimetry systems in order that the absorbed dose be determined directly from photometric measurements.

Davies, J. B.; Bosi, S. G.; Baldock, C.

2013-06-01

106

Indirect complexometric titration of sodium and potassium with EDTA  

Microsoft Academic Search

Sodium is precipitated as sodium zinc uranyl acetate, filtered and dissolved in water, and zinc is titrated with EDTA using eriochrome black T as indicator. Potassium is precipitated as potassium sodium cobaltinitrite and dissolved in hot water containing little hydrochloric acid. The blue colored solution produced by cobalt in solution, with ammonium thiocyanate and acetone was titrated with EDTA until

Buddhadev Sen

1957-01-01

107

Successive determination of praseodymium and ytterbium by coulometric complexometric titration  

Microsoft Academic Search

A method is described for the successive coulometric complexometric titration of microgram levels of light and heavy rare earth elements. The total amount of light and heavy rare earth elements is titrated by electrogenerating titrant EDTA on the mercury pool as a cathode. Then, the mercury pool is switched as an anode, electrogenerating Hg\\/sup 2 +\\/, and is used to

S. Chun-Nian; L. Jing-Ci; N. Qi-Dao; C. Mou-Sen

1982-01-01

108

Quantitative Analysis of Sulfate in Water by Indirect EDTA Titration  

ERIC Educational Resources Information Center

The determination of sulfate concentration in water by indirect EDTA titration is an instructive experiment that is easily implemented in an analytical chemistry laboratory course. A water sample is treated with excess barium chloride to precipitate sulfate ions as BaSO[subscript 4](s). The unprecipitated barium ions are then titrated with EDTA.…

Belle-Oudry, Deirdre

2008-01-01

109

A Closer Look at Acid-Base Olfactory Titrations  

ERIC Educational Resources Information Center

Olfactory titrations using raw onions and eugenol as acid-base indicators are reported. An in-depth investigation on olfactory titrations is presented to include requirements for potential olfactory indicators and protocols for using garlic, onions, and vanillin as acid-base olfactory indicators are tested.

Neppel, Kerry; Oliver-Hoyo, Maria T.; Queen, Connie; Reed, Nicole

2005-01-01

110

Titration and hysteresis in epigenetic chromatin silencing.  

PubMed

Epigenetic mechanisms of silencing via heritable chromatin modifications play a major role in gene regulation and cell fate specification. We consider a model of epigenetic chromatin silencing in budding yeast and study the bifurcation diagram and characterize the bistable and the monostable regimes. The main focus of this paper is to examine how the perturbations altering the activity of histone modifying enzymes affect the epigenetic states. We analyze the implications of having the total number of silencing proteins, given by the sum of proteins bound to the nucleosomes and the ones available in the ambient, to be constant. This constraint couples different regions of chromatin through the shared reservoir of ambient silencing proteins. We show that the response of the system to perturbations depends dramatically on the titration effect caused by the above constraint. In particular, for a certain range of overall abundance of silencing proteins, the hysteresis loop changes qualitatively with certain jump replaced by continuous merger of different states. In addition, we find a nonmonotonic dependence of gene expression on the rate of histone deacetylation activity of Sir2. We discuss how these qualitative predictions of our model could be compared with experimental studies of the yeast system under anti-silencing drugs. PMID:23588040

Dayarian, Adel; Sengupta, Anirvan M

2013-06-01

111

Sloan Digital Sky Survey photometric telescope automation and observing software  

SciTech Connect

The photometric telescope (PT) provides observations necessary for the photometric calibration of the Sloan Digital Sky Survey (SDSS). Because the attention of the observing staff is occupied by the operation of the 2.5 meter telescope which takes the survey data proper, the PT must reliably take data with little supervision. In this paper we describe the PT's observing program, MOP, which automates most tasks necessary for observing. MOP's automated target selection is closely modeled on the actions a human observer might take, and is built upon a user interface that can be (and has been) used for manual operation. This results in an interface that makes it easy for an observer to track the activities of the automating procedures and intervene with minimum disturbance when necessary. MOP selects targets from the same list of standard star and calibration fields presented to the user, and chooses standard star fields covering ranges of airmass, color, and time necessary to monitor atmospheric extinction and produce a photometric solution. The software determines when additional standard star fields are unnecessary, and selects survey calibration fields according to availability and priority. Other automated features of MOP, such as maintaining the focus and keeping a night log, are also built around still functional manual interfaces, allowing the observer to be as active in observing as desired; MOP's automated features may be used as tools for manual observing, ignored entirely, or allowed to run the telescope with minimal supervision when taking routine data.

Eric H. Neilsen, Jr. et al.

2002-10-16

112

Photometric Studies of GEO Debris  

NASA Technical Reports Server (NTRS)

The photometric signature of a debris object can be useful in determining what the physical characteristics of a piece of debris are. We report on optical observations in multiple filters of debris at geosynchronous Earth orbit (GEO). Our sample is taken from GEO objects discovered in a survey with the University of Michigan's 0.6-m aperture Schmidt telescope MODEST (for Michigan Orbital DEbris Survey Telescope), and then followed up in real-time with the SMARTS (Small and Medium Aperture Research Telescope System) 0.9-m at CTIO for orbits and photometry. Our goal is to determine 6 parameter orbits and measure colors for all objects fainter than R = 15 th magnitude that are discovered in the MODEST survey. At this magnitude the distribution of observed angular rates changes significantly from that of brighter objects. There are two objectives: 1. Estimate the orbital distribution of objects selected on the basis of two observational criteria: brightness (magnitude) and angular rates. 2. Obtain magnitudes and colors in standard astronomical filters (BVRI) for comparison with reflectance spectra of likely spacecraft materials. What is the faint debris likely to be? In this paper we report on the photometric results. For a sample of 50 objects, more than 90 calibrated sequences of R-B-V-I-R magnitudes have been obtained with the CTIO 0.9-m. For objects that do not show large brightness variations, the colors are largely redder than solar in both B-R and R-I. The width of the color distribution may be intrinsic to the nature of the surfaces, but also could be that we are seeing irregularly shaped objects and measuring the colors at different times with just one telescope. For a smaller sample of objects we have observed with synchronized CCD cameras on the two telescopes. The CTIO 0.9-m observes in B, and MODEST in R. The CCD cameras are electronically linked together so that the start time and duration of observations are the same to better than 50 milliseconds. Thus the B-R color is a true measure of the surface of the debris piece facing the telescopes for that observation. Any change in color reflects a real change in the debris surface.

Seitzer, Patrick; Cowardin, Heather M.; Barker, Edwin; Abercromby, Kira J.; Foreman, Gary; Horstman, Matt

2009-01-01

113

Photometric Study of Uranian Satellites  

NASA Astrophysics Data System (ADS)

The best summary of my work at NASA is expressed in the following abstract, submitted the Division for Planetary Science of the American Astronomical Society and to be presented at the annual meeting in Madison in October. We report photometric measurements of Uranian satellites Miranda, Ariel, Umbriel and Titania (10.4 Aug. 1995), and Neptune's satellite Triton (21.2 Sept. 1995) with the infrared camera (IRCAM) and standard J (1.13 - 1.42 microns), H (1.53 - 1.81 microns), and K (2.00 - 2.41 microns) filters at the 3.8-m UKIRT telescope on Mauna Kea. The individual images frames are 256 x 256 pixels with a platescale of .286 arcsec/pixel, resulting in a 1.22 arc min field of view. This summer brought the IR photometry measurements nearly to a close. As indicated by the abstract above, I will present this work at the annual DPS meeting in October. In anticipation of the opening of the new Carl Sagan Laboratory for Cosmochemisty, of which I will be a participating member, I also devoted a considerable fraction of the summer to learning the biochemistry which underlies the experiments to be conducted. To put the end of the summary close to the beginning, it was a most productive summer.

Kesten, Philip R.

1998-10-01

114

Improved Rotor for Multistation Photometric Analyzer.  

National Technical Information Service (NTIS)

An improved rotor for a multistation photometric analyzer is described which is capable of operation without gravitational assistance to effect transfer or retention of liquids. The rotor comprises a laminated disk-shaped member with a central opaque disk...

J. C. Mailen

1971-01-01

115

Photometric and Near Infrared Radiometric Measurement Systems.  

National Technical Information Service (NTIS)

This report describes the details of calibration, operation, and constraints of a photometric and a 0.73-0.97 micrometers near infrared radiometric measurement system, both constructed at NAVWPNSUPPCEN Crane for measurements of flare plume candlepower and...

F. L. Burton C. E. Dinerman

1976-01-01

116

The Palomar Transient Factory Photometric Calibration  

NASA Astrophysics Data System (ADS)

The Palomar Transient Factory (PTF) provides multiple epoch imaging for a large fraction of the celestial sphere. Here, we describe the photometric calibration of the PTF data products that allows the PTF magnitudes to be related to other magnitude systems. The calibration process utilizes Sloan Digital Sky Survey (SDSS) r˜16 mag point-source objects as photometric standards. During photometric conditions, this allows us to solve for the extinction coefficients and color terms and to estimate the camera illumination correction. This also enables the calibration of fields that are outside the SDSS footprint. We test the precision and repeatability of the PTF photometric calibration. Given that PTF is observing in a single filter each night, we define a PTF calibrated magnitude system for the R band and g band. We show that, in this system, ?59% (47%) of the photometrically calibrated PTF R-band (g-band) data achieve a photometric precision of 0.02--0.04 mag and have color terms and extinction coefficients that are close to their average values. Given the objects'' color, the PTF magnitude system can be converted to other systems. Moreover, a night-by-night comparison of the calibrated magnitudes of individual stars observed on multiple nights shows that they are consistent to a level of ?0.02 mag. Most of the data that were taken under nonphotometric conditions can be calibrated relative to other epochs of the same sky footprint obtained during photometric conditions. We provide a concise guide describing how to use the PTF photometric-calibration data products, as well as the transformations between the PTF magnitude system and the SDSS and Johnson-Cousins systems.

Ofek, E. O.; Laher, R.; Law, N.; Surace, J.; Levitan, D.; Sesar, B.; Horesh, A.; Poznanski, D.; van Eyken, J. C.; Kulkarni, S. R.; Nugent, P.; Zolkower, J.; Walters, R.; Sullivan, M.; Agüeros, M.; Bildsten, L.; Bloom, J.; Cenko, S. B.; Gal-Yam, A.; Grillmair, C.; Helou, G.; Kasliwal, M. M.; Quimby, R.

2012-01-01

117

A Titration Technique for Demonstrating a Magma Replenishment Model.  

ERIC Educational Resources Information Center

Conductiometric titrations can be used to simulate subduction-setting volcanism. Suggestions are made as to the use of this technique in teaching volcanic mechanisms and geochemical indications of tectonic settings. (JN)

Hodder, A. P. W.

1983-01-01

118

Complexometric Titration of Zinc: An Analytical Chemistry Laboratory Experiment  

NASA Astrophysics Data System (ADS)

Complexometric titrations with EDTA have traditionally been performed in undergraduate analytical chemistry courses to determine the calcium or magnesium content of water. These titrations are performed at a basic pH, where the formation constants of Ca-EDTA and Mg-EDTA complexes are high. These types of problems are well-treated in the analytical chemistry textbooks. In contrast, treatment of metal ions whose EDTA complexes occur significantly at low pH (e.g., Zn2+, Fe3+, Cu2+, Ni2+, Pb2+, Al3+) is sparse. An incorrect conclusion can be reached by the student that practical EDTA titrations are only performed at high pH. In addition, widening the window of possible metal ions for complexometric titration affords the possibility of analyzing real world products, such as the cold lozenges discussed in the article.

Novick, S. G.

1997-12-01

119

Application of various electrodes in potentiometric titration of calcium.  

PubMed

In complexometric titrations various indicator electrodes may be employed for monitoring the course of titration and for detection of the end-point. Several of them, including the silver, mercury, bivalent cation membrane, calcium membrane and manganese dioxide electrodes were investigated and compared in their usefulness. As titrant, EDTA was mostly used, but results with similar chelating titrants were also obtained. The practical utility of the electrodes in titrations depends on their selectivity, magnitude of the end-point break and precision in determination of the end-point. For the electrodes studied, in some instances there is good correlation between the theoretical and experimental titration curves, but it is not always possible to predict the electrode response in the low activity range. In other cases poor correlation does not mean that reasonably good analytical results may not be obtained. PMID:18961322

Hulanicki, A; Trojanowicz, M

1973-07-01

120

Quantification of hydrolytic charge loss of DMAEA-Q-based polyelectrolytes by proton NMR spectroscopy and implications for colloid titration.  

PubMed

Copolymers of acrylamide and quaternised dimethylaminoethyl acrylate (DMAEA-Q) constitute an economically important range of cationic polyelectrolytes used in sludge conditioning. The latter treatment involves charge neutralisation and bridging induced by these polymers. Since both of these phenomena rely on charge-driven sorption onto the negatively charged colloidal particles, the accurate assessment of their charge density is of primary importance in polyelectrolyte characterisation. The experimental determination of this characteristic generally relies on colloidal charge titration, in which the cationic polymer is titrated against an anionic polymer. Hereby, one of the requirements to have a stoichiometric reaction between the oppositely charged polymers is a sufficiently low polymer concentration. In this study, it is shown that such a low polymer concentration may entail a pronounced hydrolysis effect for DMAEA-Q-based polymers, which leads to a release of the cationic side groups and hence causes considerable errors on the charge titration results. Proton nuclear magnetic resonance spectroscopy was applied to investigate the fast hydrolysis kinetics of DMAEA-Q polymers together with time-dependent charge titration measurements. Diffusion NMR spectroscopy was used to assist in establishing the nature of the hydrolysis compounds. The results from both techniques indicate that a high degree of hydrolysis is reached within minutes after dilution of a concentrated polymer stock solution into aqueous solutions of slightly acidic to neutral pH values. Therefore, a modification to the classic colloid titration procedure is proposed, using a buffered dilution liquid to avoid polymer hydrolysis. It is shown that a buffer pH value of 4.5 avoids not only polymer hydrolysis effects but also possible protonation of the anionic titrant, thereby avoiding overestimation of the charge density. By means of this procedure, reproducible and time-independent charge titration results are obtained. PMID:18295818

Saveyn, Hans; Hendrickx, Pieter M S; Dentel, Steven K; Martins, José C; Van der Meeren, Paul

2008-05-01

121

Complexometric Titration of Metals Using a Lead Selective Electrode  

Microsoft Academic Search

A solid state lead selective electrode is used satisfactorily to indicate the end point eufing the complexometric titration of Ni, Co, Zn and V (IV) with EDTA, CDTA, and DTPA, in presence of a small amount of the corresponding lead complex. The optimum pH for the titration was in the range of 4.0 to 6.0. The quantity of lead complex

Maria L. Suarez; Alfredo Calvo; Luis E. Leon

1986-01-01

122

PHOTOMETRIC ORBITS OF EXTRASOLAR PLANETS  

SciTech Connect

We define and analyze the photometric orbit (PhO) of an extrasolar planet observed in reflected light. In our definition, the PhO is a Keplerian entity with six parameters: semimajor axis, eccentricity, mean anomaly at some particular time, argument of periastron, inclination angle, and effective radius, which is the square root of the geometric albedo times the planetary radius. Preliminarily, we assume a Lambertian phase function. We study in detail the case of short-period giant planets (SPGPs) and observational parameters relevant to the Kepler mission: 20 ppm photometry with normal errors, 6.5 hr cadence, and three-year duration. We define a relevant 'planetary population of interest' in terms of probability distributions of the PhO parameters. We perform Monte Carlo experiments to estimate the ability to detect planets and to recover PhO parameters from light curves. We calibrate the completeness of a periodogram search technique, and find structure caused by degeneracy. We recover full orbital solutions from synthetic Kepler data sets and estimate the median errors in recovered PhO parameters. We treat in depth a case of a Jupiter body-double. For the stated assumptions, we find that Kepler should obtain orbital solutions for many of the 100-760 SPGP that Jenkins and Doyle estimate Kepler will discover. Because most or all of these discoveries will be followed up by ground-based radial velocity observations, the estimates of inclination angle from the PhO may enable the calculation of true companion masses: Kepler photometry may break the 'msin i' degeneracy. PhO observations may be difficult. There is uncertainty about how low the albedos of SPGPs actually are, about their phase functions, and about a possible noise floor due to systematic errors from instrumental and stellar sources. Nevertheless, simple detection of SPGPs in reflected light should be robust in the regime of Kepler photometry, and estimates of all six orbital parameters may be feasible in at least a subset of cases.

Brown, Robert A. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)], E-mail: rbrown@stsci.edu

2009-09-10

123

The effect of photometric and geometric context on photometric and geometric lightness effects  

PubMed Central

We measured the lightness of probe tabs embedded at different orientations in various contextual images presented on a computer-controlled stereo display. Two background context planes met along a horizontal roof-like ridge. Each plane was a graphic rendering of a set of achromatic surfaces with the simulated illumination for each plane controlled independently. Photometric context was varied by changing the difference in simulated illumination intensity between the two background planes. Geometric context was varied by changing the angle between them. We parsed the data into separate photometric effects and geometric effects. For fixed geometry, varying photometric context led to linear changes in both the photometric and geometric effects. Varying geometric context did not produce a statistically reliable change in either the photometric or geometric effects.

Lee, Thomas Y.; Brainard, David H.

2014-01-01

124

Complexometric determination of metal ions by microscopic diffusional titration.  

PubMed

Acid/base titrations of pico- and femtoliter microsamples have been performed previously using a diffusional microburet (DMB) for reagent delivery in a simple droplet-heptane system (Gratzl, M.; Yi, C. Anal. Chem. 1993, 65, 2085-2088). The lowest delivery rate achieved with a DMB was about 6 fmol/s, which would correspond to about a 1 microL/year volumetric flow rate with a hypothetical equivalent mechanical delivery scheme (Yi, C.; Gratzl, M. Anal. Chem. 1994, 66, 1976-1982). In this work, the feasibility of complexometric titrations in microscopic samples is explored. Stability of pH in the microdroplets required for different determinations and the effects of DMB shank geometry on titration characteristics are also studied. Diffusional microtitrations of Fe(III), Zn(II), and Cu(II) have been performed with EDTA. Xylenol orange and Eriochrome Black T provide clear color changes at the end point of the respective titrations, despite the microscopic size of the samples (between 16 and 1570 pL, corresponding to diameters between 30 and 144 microns). Random errors of the determinations relative to full scale were 6.6% for Fe(III), 5.8% for Cu(II), and 7.9% for Zn(II). The pH required for EDTA titrations of the individual metal ions stays stable in the acidic range. This makes the microscopic titration of a number of metal ions, such as Fe(III), Fe(II), Cu(II), and Pb(II), feasible in a simple droplet-heptane system without any modification. With a higher density of strongly alkaline buffer droplets (about 100 droplets/mm2) sprayed on the bottom of the Petri dish, or by flushing N2 above the heptane, the microscopic samples can also be kept alkaline despite ambient CO2 present. In this way, Zn(II) can also be titrated in microdroplets, requiring a pH around 10. This work renders it possible to perform a variety of complexometric titrations and other chemical manipulations in microdroplets even if they need to be kept alkaline. Similar titrations in single biological cells to assess intracellular buffer capacities of different metal ions, such as Ca(II) and Mg(II), are underway. PMID:8815747

Yi, C; Huang, D; Gratzl, M

1996-05-01

125

Titrated oxygen requirement and prognostication in idiopathic pulmonary fibrosis  

PubMed Central

Background The supplemental oxygen flow rate is a common bedside measure of gas exchange impairment. We aimed to determine whether a titrated oxygen requirement predicted mortality in idiopathic pulmonary fibrosis. Methods We examined 104 adults with idiopathic pulmonary fibrosis enrolled in a prospective cohort study and a validation cohort of 151 adults with a variety of interstitial lung diseases. The titrated oxygen requirement was defined as the lowest oxygen flow rate required to maintain an oxyhemoglobin saturation of 96% while standing. Cox proportional hazards models and time-dependent receiver operating characteristic curves were used to examine survival time. Results A higher titrated oxygen requirement was associated with a greater mortality rate independent of forced vital capacity and six-minute walk test results in idiopathic pulmonary fibrosis (adjusted hazard ratio per 1 L/min = 1.10, 95% confidence interval 1.01 to 1.20). The titrated oxygen requirement was at least as accurate as pulmonary function and six-minute walk testing at predicting 1-year mortality. Findings were similar in other interstitial lung diseases. Conclusion The titrated oxygen requirement is a simple, inexpensive bedside measurement that aids prognostication in idiopathic pulmonary fibrosis.

Hook, Jaime L.; Arcasoy, Selim M.; Zemmel, David; Bartels, Matthew; Kawut, Steven M.; Lederer, David J.

2011-01-01

126

Potentiometric titration and equivalent weight of humic acid  

USGS Publications Warehouse

The "acid nature" of humic acid has been controversial for many years. Some investigators claim that humic acid is a true weak acid, while others feel that its behaviour during potentiometric titration can be accounted for by colloidal adsorption of hydrogen ions. The acid character of humic acid has been reinvestigated using newly-derived relationships for the titration of weak acids with strong base. Re-interpreting the potentiometric titration data published by Thiele and Kettner in 1953, it was found that Merck humic acid behaves as a weak polyelectrolytic acid having an equivalent weight of 150, a pKa of 6.8 to 7.0, and a titration exponent of about 4.8. Interdretation of similar data pertaining to the titration of phenol-formaldehyde and pyrogallol-formaldehyde resins, considered to be analogs for humic acid by Thiele and Kettner, leads to the conclusion that it is not possible to differentiate between adsorption and acid-base reaction for these substances. ?? 1960.

Pommer, A. M.; Breger, I. A.

1960-01-01

127

NONAQUEOUS POTENTIOMETRIC TITRATION AND ELEMENTAL ANALYSIS OF HIGH-BOILING DISTILLATES OF SAUDI ARABIAN CRUDE OILS  

Microsoft Academic Search

Nonaqueous potentiometric titration and elemental analysis were used to study basic and nonbasic functionalities present in high-boiling distillates of four Saudi Arabian crude oils. Model nitrogen compounds were titrated under similar titration conditions to differentiate them into strong, weak and nonbasic species. The strong bases titrated were due to the presence of pyridine and its benzologs like acridines, phe-nanthridines and

Mohammad Farhat Ali; Mohammed Ashraf Ali

1988-01-01

128

Photometric Analysis with CONCAM Sky Monitoring Data  

NASA Astrophysics Data System (ADS)

Practical data analysis techniques useful with CONtinuous CAMera (CONCAM) data are discussed. Analysis is presented of distortion near the edges of the wide CONCAM fields and how these affect the utility of data stored at http://concam.net. Preliminary photometric analyses limiting the peak optical brightness of the optical counterparts to two gamma-ray bursts, GRB000926 and GRB001005, are presented. A preliminary photometric analysis is also given for Polaris and the variability of other bright stars. We discuss potential future scientific returns of analyzing publicly archive CONCAM data available at concam.net.

Perez-Ramirez, D.; Nemiroff, R. J.; Pereira, W. E.; Rafert, J. B.; Ftaclas, C.

2000-12-01

129

Enceladus - Implications of its unusual photometric properties  

NASA Technical Reports Server (NTRS)

Voyager 1 and 2 images are used to ascertain the photometric properties of Enceladus up to a 43-deg phase angle. The lack of correlation noted between spectrophotometric properties and terrain type indicates that optical characteristics result from a recently-deposited, ubiquitous surface layer that may have originated on the E-ring of Saturn. Enceladus' distinctive phase and photometric functions can be accounted for by the high degree of surface multiple scattering; observations to date indicate that the Enceladus regolith's textural characteristics are similar to those of other icy satellites of Saturn.

Buratti, Bonnie J.

1988-01-01

130

Two-phase titration of cerium(III) by permanganate  

SciTech Connect

This paper presents a method for the two-phase titrimetric determination of cerium(III) with permanganate which does not require an expenditure of sugar and preliminary removal of chlorides and nitrates. The interaction of cerium(III) with permanganate at room temperature was studied as a function of the pH, the concentration of pyrophosphate, tetraphenylphosphonium (TPP), permanganate, and extraneous compounds, the rate of titration, and the time of stay of the solution in air before titration. The investigations were conducted according to the following methodology: water, solution of cerium(III) pyrophosphate, and TPP were introduced into an Erlenmeyer flask with a side branch near the bottom for clearer observation of the color of the chloroform phase. The authors established the given pH value, poured the water into a volume of 50 ml, and added chloroform. The result was titrated with permanganate solutions of various concentrations until a violet color appeared in the chloroform phase.

Lazarev, A.I.; Lazareva, V.I.; Gerko, V.V.

1987-02-01

131

Metal oxide electrodes as sensors in complexometric titrations.  

PubMed

EDTA titrations of lead and manganese, and of some other ions by using these as indicator ions, have been followed potentiometrically with PbO(2) and MnO(2) electrodes. Explanations are put forward for the anomalies observed in the titration curves. With the MnO(2) electrode, formation of an Mn(III)-EDTA complex is responsible for the diminished potential breaks. With the PbO(2) electrode the decrease in the potential break and the distortion of the curves in acid solution may be due to reaction between electrode coating and titrant. The MnO(2) electrode has been used for titrations of Ba(2+) Ca(2+), Cd(2+) and Cu(2+) with errors < 1%. PMID:18961911

Hulanicki, A; Trojanowicz, M

1976-07-01

132

Coulometric titration of D(+)-glucose using its enzymatic oxidation.  

PubMed

A definitive method is described for the indirect assay of milligram quantities of D(+)-glucose by coulometric titration. D(+)-Glucose was aerobically oxidized by glucose oxidase in an acetate buffer solution (pH 5.1). Subsequently, the enzymatically formed hydrogen peroxide was titrated coulometrically with electrogenerated hypobromite in sodium bromide-sodium tetraborate medium of pH 8.6, with biamperometric end-point detection. Parameters affecting the enzymatically catalyzed oxidation and coulometric titration were evaluated. The optimized conditions for the oxidation of up to 20 mg of D(+)-glucose include the addition of 4500 U of glucose oxidase and stirring over a 10-min interval at 25 degrees C. Under proposed conditions, the assay values of several commercial D(+)-glucose reagents were somewhat lower than the guaranteed minimum values, with RSDs (n = 5) of 0.071 - 0.106%. PMID:11990540

Tanaka, T; Shutto, E; Mizoguchi, T; Fukushima, K

2001-02-01

133

The Asiago Database on Photometric Systems (ADPS). I. Census parameters for 167 photometric systems  

NASA Astrophysics Data System (ADS)

The Asiago Database on Photometric Systems (ADPS) is a compilation of basic information and reference data on 167 optical, ultraviolet and infrared photometric systems. Thirty-four additional systems are briefly described. In compiling this census we have relied on published information only. In Paper II the photometric systems will be inter-compared, calibrated and parameterised by means of synthetic photometry using uniform criteria and the same set of input spectra and extinction laws. The ADPS is reachable at http://ulisse.pd.astro.it/Astro/ADPS/ or via http://www.pd.astro.it/

Moro, D.; Munari, U.

2000-12-01

134

Generalized theory for two-phase ion-pair and complexometric titrations. I. Two-phase titrations without side reactions.  

PubMed

A systematic theoretical treatment of the two-phase titration based on ion-pair and metal-complex formation is presented. Equations for the titration curve, accuracy, equivalence point and choice of the indicator are derived. Much attention is paid to the parameters determining the 'titratability' viz. extraction constant, distribution constant, phase volume ratio and the concentration of the analyte. Special attention is given to the role of intermediate ion-pair and metal-complex formation in the aqueous phase. The ion-pair formation in aqueous solution is examined closer by means of the relationship between the association constant in water, the degree of dissociation of the ion pair (alpha) and the concentration of the counter ion. The merits of this theoretical treatment are illustrated with literature examples. PMID:4080511

Bult, A; Dingjan, H A; Dreijer-van der Glas, S M; Van Bennekom, W P

1985-12-13

135

Photometric Equipment for Pulsed Light Sources.  

National Technical Information Service (NTIS)

A unit for photometric measurement of pulsed light sources is described. This unit consists of three instruments: an FIL photometer for flash lamps, an FML-m photometer for lasers and a KOS standard light pulse generator. The FIL photometer may be used fo...

A. A. Volkenshtein V. P. Efremov E. V. Kuvaldin O. K. Matveeva V. M. Sazonov

1968-01-01

136

New Photometric Observations of RS Oph  

NASA Astrophysics Data System (ADS)

The recurrent nova RS Oph is a long period (~455 days) binary system consisting of a hot white dwarf with mass close to the Chandrasekhar limit and an M-type giant secondary. Here we present the results of photometric observations of this nova which were made during recent years with the telescopes of the Sternberg Astronomical Institute in Crimea.

Voloshina, Irina; Metlov, Vladimir

2013-01-01

137

SDSS Coadd: A Galaxy Photometric Redshift Catalog.  

National Technical Information Service (NTIS)

We present and describe a catalog of galaxy photometric redshifts (photo-z's) for the Sloan Digital Sky Survey (SDSS) Coadd Data. We use the Artificial Neural Network (ANN) technique to calculate photo-zs and the Nearest Neighbor Error (NNE) method to est...

J. Annis M. S. Santos R. Reis R. Ribamar S. Dodelson

2011-01-01

138

Illumination Invariant Face Recognition Using Photometric Stereo  

Microsoft Academic Search

SUMMARY In this paper, we propose an elegant approach for illumination invariant face recognition based on the photomet- ric stereo technique. The basic idea is to reconstruct the surface normal and the albedo of a face using photometric stereo images, and then use them as the illumination independent model of the face. And, we have investigated the optimal light source

Seok-cheol Kee; Sang Uk Lee; Kyoung Mu Lee

1998-01-01

139

THE Pan-STARRS1 PHOTOMETRIC SYSTEM  

SciTech Connect

The Pan-STARRS1 survey is collecting multi-epoch, multi-color observations of the sky north of declination -30 Degree-Sign to unprecedented depths. These data are being photometrically and astrometrically calibrated and will serve as a reference for many other purposes. In this paper, we present our determination of the Pan-STARRS1 photometric system: g{sub P1}, r{sub P1}, i{sub P1}, z{sub P1}, y{sub P1}, and w{sub P1}. The Pan-STARRS1 photometric system is fundamentally based on the Hubble Space Telescope Calspec spectrophotometric observations, which in turn are fundamentally based on models of white dwarf atmospheres. We define the Pan-STARRS1 magnitude system and describe in detail our measurement of the system passbands, including both the instrumental sensitivity and atmospheric transmission functions. By-products, including transformations to other photometric systems, Galactic extinction, and stellar locus, are also provided. We close with a discussion of remaining systematic errors.

Tonry, J. L.; Burgett, W. S.; Chambers, K. C.; Hodapp, K. W.; Kaiser, N.; Kudritzki, R.-P.; Magnier, E. A.; Morgan, J. S.; Wainscoat, R. J. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Stubbs, C. W.; Shivvers, I. S. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Lykke, K. R. [National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899 (United States); Doherty, P. [Department of Physics, Harvard University, 17 Oxford Street, Cambridge, MA 02138 (United States); Price, P. A. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

2012-05-10

140

Photometric auroral observations at the South Pole  

Microsoft Academic Search

Auroral photometric measurements were obtained at the South Pole, throughout the austral winter of 1972. Observed auroral emissions included 4278 A N2(+), 4861 A H sub beta and 5577 A and 6300 A OI. A comprehensive study of auroral emissions and riometer absorption associated with the solar flare activity of August 1972 was conducted. Energetic solar protons measured by satellite

E. J. Weber

1975-01-01

141

System for clinical photometric stereo endoscopy  

NASA Astrophysics Data System (ADS)

Photometric stereo endoscopy is a technique that captures information about the high-spatial-frequency topography of the field of view simultaneously with a conventional color image. Here we describe a system that will enable photometric stereo endoscopy to be clinically evaluated in the large intestine of human patients. The clinical photometric stereo endoscopy system consists of a commercial gastroscope, a commercial video processor, an image capturing and processing unit, custom synchronization electronics, white light LEDs, a set of four fibers with diffusing tips, and an alignment cap. The custom pieces that come into contact with the patient are composed of biocompatible materials that can be sterilized before use. The components can then be assembled in the endoscopy suite before use. The resulting endoscope has the same outer diameter as a conventional colonoscope (14 mm), plugs into a commercial video processor, captures topography and color images at 15 Hz, and displays the conventional color image to the gastroenterologist in real-time. We show that this system can capture a color and topographical video in a tubular colon phantom, demonstrating robustness to complex geometries and motion. The reported system is suitable for in vivo evaluation of photometric stereo endoscopy in the human large intestine.

Durr, Nicholas J.; González, Germán.; Lim, Daryl; Traverso, Giovanni; Nishioka, Norman S.; Vakoc, Benjamin J.; Parot, Vicente

2014-02-01

142

Direct analysis of bottom sediments by a microcoulometric titration method for determination of total organic halide pollutants  

Microsoft Academic Search

.  Up to now the content of the organic halides in sediments was measured as extractable organic halides compounds by different\\u000a methods including microcoulometric titration one. We describe a procedure for microcoulometric determination of total organic\\u000a halide pollutants by using a direct combustion of the sediments into the microcoulometric system furnace. An accelerated removal\\u000a of the inorganic chlorides by reaction with

Pavlina G. Ivanova; Zara V. Aneva

2008-01-01

143

Philosophy and updating of the asteroid photometric catalogue  

NASA Technical Reports Server (NTRS)

The Asteroid Photometric Catalogue now contains photometric lightcurves for 584 asteroids. We discuss some of the guiding principles behind it. This concerns both observers who offer input to it and users of the product.

Magnusson, Per; Barucci, M. Antonietta; Capria, M. T.; Dahlgren, Mats; Fulchignoni, Marcello; Lagerkvist, C. I.

1992-01-01

144

Direct measurement of protein binding energetics by isothermal titration calorimetry  

Microsoft Academic Search

Of all the techniques that are currently available to measure binding, isothermal titration calorimetry is the only one capable of measuring not only the magnitude of the binding affinity but also the magnitude of the two thermodynamic terms that define the binding affinity: the enthalpy (?H) and entropy (?S) changes. Recent advances in instrumentation have facilitated the development of experimental

Stephanie Leavitt; Ernesto Freire

2001-01-01

145

Potentiometric titration of gold, platinum, and some other precious metals.  

National Technical Information Service (NTIS)

Gold, platinum, and several other platinum metals can be determined by titration with cetylpyridinium chloride (CPC). CPC forms a precipitate with AuCl(sub 4)(sup (minus)) and PtCl(sub 6)(sup 2(minus)). Differentiation of AuCl(sub 4(minus)) and PtCl(sub 6...

W. S. Selig

1991-01-01

146

Using Spreadsheets to Produce Acid-Base Titration Curves.  

ERIC Educational Resources Information Center

Describes two spreadsheets for producing acid-base titration curves, one uses relatively simple cell formulae that can be written into the spreadsheet by inexperienced students and the second uses more complex formulae that are best written by the teacher. (JRH)

Cawley, Martin James; Parkinson, John

1995-01-01

147

Successive determination of praseodymium and ytterbium by coulometric complexometric titration  

SciTech Connect

A method is described for the successive coulometric complexometric titration of microgram levels of light and heavy rare earth elements. The total amount of light and heavy rare earth elements is titrated by electrogenerating titrant EDTA on the mercury pool as a cathode. Then, the mercury pool is switched as an anode, electrogenerating Hg/sup 2 +/, and is used to titrate EDTA which is displaced from its light rare earth elements complex by malic acid that has been added prior to the electrogenerating Hg/sup 2 +/. The heavy rare earth elements can be determined from the total rare earth elements minus the result of displacement titration of EDTA which is equivalent to the light rare earth elements. A 10-30 ..mu..g sample of light and heavy rare earth elements (Pr and Yb, La and Lu, Nd and Tm) can be determined successively. Errors and standard deviation are not more than 2.5% and 0.20, respectively. 2 tables, 5 figures.

Chun-Nian, S.; Jing-Ci, L.; Qi-Dao, N.; Mou-Sen, C.

1982-06-01

148

Direct complexometric titration of thorium with versene using SPADNS  

Microsoft Academic Search

The existing volumetric methods for the determination of thorium are indirect and unsatisfactory. A direct titrimetric method for the estimation of thorium has been developed which involves the adjustment ofph, addition of 1 ml. of 0.02% SPADNS indicator, dilution to volume and titration with versene. It is based on the fact that thorium forms a coloured complex with SPADNS and

Gurupada Banerjee

1955-01-01

149

Thermometric Titration Analysis of Seawater for Chlorinity, Sulfate, and Alkalinity.  

National Technical Information Service (NTIS)

Total sulfate, chlorinity, and total alkalinity in seawater solutions have been determined by thermometric titration. The precision of the analyses was 0.3% for sulfate, 0.04% for chlorinity, and 0.1% for total alkalinity. Because of their simplicity, spe...

F. J. Millero, S. R. Schrager, L. D. Hansen

1973-01-01

150

Constant-Current Coulometric Titration of Hydrochloric Acid  

Microsoft Academic Search

The titration of a strong acid with a strong base and the electrolysis of water are two classic laboratory exercises that are either performed or demonstrated in secondary school classrooms in order to introduce two important areas of chemsitry: acid-base chemistry and electrochemistry. In this experiment we have combined these two classical experiments into one complete laboratory experience. Here we

James Swim; Edward Earps; Laura M. Reed; David Paul

1996-01-01

151

Optimal Reconstruction of Approximate Planar Surfaces Using Photometric Stereo  

Microsoft Academic Search

Photometric stereo can be used to obtain a fast and noncontact surface reconstruction of Lambertian surfaces. Despite several published works concerning the uncertainties and optimal light configurations of photometric stereo, no solutions for optimal surface reconstruction from noisy real images have been proposed. In this paper, optimal surface reconstruction methods for approximate planar textured surfaces using photometric stereo are derived,

Toni Kuparinen; Ville Kyrki

2009-01-01

152

Dual photometric-contactless conductometric detector for capillary electrophoresis  

Microsoft Academic Search

A combined detection system involving simultaneous absorption photometric and contactless conductometric measurements at the same place of the fused-silica separation capillary has been designed. The measurements are mutually independent and the static and dynamic properties of the detection are fully comparable with those characteristic of individual photometric and conductometric detectors. Optical fibers are used to carry the photometric signal, whereas

Tommy Chvojka; Ivan Jel??nek; František Opekar; Karel Štul??k

2001-01-01

153

Titrations using an apparatus for recording the antilogarithm of pH or pM.  

PubMed

A titration apparatus plotting either the concentration of sample ion or the concentration of titrant ion has been tested. An antilog apparatus, converting measured e.m.f. values into concentrations is connected to ordinary titration equipment. The instrument has been tested by means of acid-base titrations (titrations of mixtures of weak acids and of a weak and a strong acid), precipitation titrations (determination of the chloride concentration in tap-water, titration of mixtures of halides), titrations with ion-selective electrodes (determination of the fluoride content of toothpaste) and complexometric titrations (determination of copper with EDTA, using mercuric ion as indicator ion and amalgamated silver rod as indicator electrode, or using a copper-selective indicator electrode). The method considerably simplifies the evaluation of the results as compared to conventional potentiometric titrations. PMID:18961596

Johansson, A

1974-12-01

154

Direct photometric determination of fluorides in potassium chloride and iodide  

SciTech Connect

An attempt is made to apply the technique of determining fluorides with xylenol orange and sulfochlorophenol S as being the most sensitive in the analysis of of fiber optics. It is known that an increase of the sensitivity of the determination can be achieved on increasing the sample size of the substance to be analyzed, and the length of the absorbing layer. However, a high salt background may have a strong influence on the course of the reaction, and a supplementary of this effect is mad. Potassium chloride and iodide were selected as model compounds. A direct photometric procedure is proposed for determining fluorides in the samples, with a determination limit of 5 x 10/sup -6/%. Such a low determination limit is achieved by increasing the sample weight to 3 g, by increasing the length of the absorbing layer in the cell to 50 mm, and by using a highly sensitive reaction for determining fluorides with zirconium and xylenol orange.

Dedkova, V.P.; Savvin, S.B.

1985-05-01

155

Testing Photometric Methods in the Euclid Testbed  

NASA Astrophysics Data System (ADS)

The Euclid satellite will investigate the distance-redshift relationship and the evolution of cosmic structures by measuring shapes and redshifts of galaxies and clusters of galaxies. The various Euclid experiments require very accurate object photometry in order to achieve its science goals. Building upon our experience in the Dark Energy Survey data management, we have developed the Euclid Testbed which allows one to compare different methods for various data processing steps such as object detection and object photometry. Our first target is testing photometric methods that are based on measurements taken on the ensemble of single images and not on co-added images. In this contribution we present and discuss the structure of the Euclid Testbed. We introduce our own single image photometry software FitPhot, and give a detailed comparison of its accuracy with other photometric methods/software.

Kümmel, M.; Mohr, J.; Desai, S.; Henderson, R.; Koppenhoefer, J.; Paech, K.; Wetzstein, M.

2014-05-01

156

Astrophysical science with a spaceborne photometric telescope  

NASA Technical Reports Server (NTRS)

The FRESIP Project (FRequency of Earth-Sized Inner Planets) is currently under study at NASA Ames Research Center. The goal of FRESIP is the measurement of the frequency of Earth-sized extra-solar planets in inner orbits via the photometric signature of a transit event. This will be accomplished with a spaceborne telescope/photometer capable of photometric precision of two parts in 100,000 at a magnitude of m(sub v) = 12.5. To achieve the maximum scientific value from the FRESIP mission, an astrophysical science workshop was held at the SETI Institute in Mountain View, California, November 11-12, 1993. Workshop participants were invited as experts in their field of astrophysical research and discussed the astrophysical science that can be achieved within the context of the FRESIP mission.

Granados, Arno F. (editor); Borucki, William J. (editor)

1994-01-01

157

Application of photometric models to asteroids  

NASA Technical Reports Server (NTRS)

The way an asteroid or other atmosphereless solar system body varies in brightness in response to changing illumination and viewing geometry depends in a very complicated way on the physical and optical properties of its surface and on its overall shape. This paper summarizes the formulation and application of recent photometric models by Hapke (1981, 1984, 1986) and by Lumme and Bowell (1981). In both models, the brightness of a rough and porous surface is parameterized in terms of the optical properties of individual particles, by shadowing between particles, and by the way in which light is scattered among collections of particles. Both models succeed in their goal of fitting the observed photometric behavior of a wide variety of bodies, but neither has led to a very complete understanding of the properties of asteroid regoliths, primarily because, in most cases, the parameters in the present models cannot be adequately constrained by observations of integral brightness alone over a restricted range of phase angles.

Bowell, Edward; Hapke, Bruce; Domingue, Deborah; Lumme, Kari; Peltoniemi, Jouni; Harris, Alan W.

1989-01-01

158

A CCD photometric camera for satellite observation  

NASA Astrophysics Data System (ADS)

A CCD camera for photometric measurement of satellites has been built, tested, and has been integrated into the Experimental Test System (ETS). This report describes the camera, the computer system and programs used to collect data, the camera's sensitivity parameters, the sensitivity of the camera on the ETS 31-inch Telescope, and its projected sensitivity on Ground-Based Electro-Optical Deep Space Surveillance System (GEODSS) main telescope.

Mayer, G. J.; MacDonald, M. J.; Pong, N. G. S.

1983-11-01

159

Can Selforganizing Maps Accurately Predict Photometric Redshifts?  

NASA Technical Reports Server (NTRS)

We present an unsupervised machine-learning approach that can be employed for estimating photometric redshifts. The proposed method is based on a vector quantization called the self-organizing-map (SOM) approach. A variety of photometrically derived input values were utilized from the Sloan Digital Sky Survey's main galaxy sample, luminous red galaxy, and quasar samples, along with the PHAT0 data set from the Photo-z Accuracy Testing project. Regression results obtained with this new approach were evaluated in terms of root-mean-square error (RMSE) to estimate the accuracy of the photometric redshift estimates. The results demonstrate competitive RMSE and outlier percentages when compared with several other popular approaches, such as artificial neural networks and Gaussian process regression. SOM RMSE results (using delta(z) = z(sub phot) - z(sub spec)) are 0.023 for the main galaxy sample, 0.027 for the luminous red galaxy sample, 0.418 for quasars, and 0.022 for PHAT0 synthetic data. The results demonstrate that there are nonunique solutions for estimating SOM RMSEs. Further research is needed in order to find more robust estimation techniques using SOMs, but the results herein are a positive indication of their capabilities when compared with other well-known methods

Way, Michael J.; Klose, Christian

2012-01-01

160

A Blind Test of Hapke's Photometric Model  

NASA Technical Reports Server (NTRS)

Hapke's bidirectional reflectance equation is a versatile analytical tool for predicting (i.e. forward modeling) the photometric behavior of a particulate surface from the observed optical and structural properties of its constituents. Remote sensing applications of Hapke s model, however, generally seek to predict the optical and structural properties of particulate soil constituents from the observed photometric behavior of a planetary surface (i.e. inverse-modeling). Our confidence in the latter approach can be established only if we ruthlessly test and optimize it. Here, we summarize preliminary results from a blind-test of the Hapke model using laboratory measurements obtained with the Bloomsburg University Goniometer (B.U.G.). The first author selected eleven well-characterized powder samples and measured the spectrophotometric behavior of each. A subset of twenty undisclosed examples of the photometric measurement sets were sent to the second author who fit the data using the Hapke model and attempted to interpret their optical and mechanical properties from photometry alone.

Helfenstein, P.; Shepard, M. K.

2003-01-01

161

Characterization of molecular interactions using isothermal titration calorimetry.  

PubMed

Isothermal titration calorimetry (ITC) is based on a simple titration of one ligand with another and the small heat changes caused by the molecular interaction are detected. From one ITC experiment the complete set of thermodynamic parameters of binding including association and dissociation constants as well as changes in enthalpy, entropy, and free energy can be derived. Using this technique almost any type of molecular interaction can be analyzed. Both ligands are in solution, and there is no need for their chemical derivatization. There are no limits as to the choice of the analysis buffer, and the analysis temperature can be set between 4 and 80 °C. This technique has been primarily applied to study the interaction between various proteins of Pseudomonas with small molecule ligands. In addition, ITC has been used to study the binding of Pseudomonas proteins to target DNA fragments. PMID:24818906

Krell, Tino; Lacal, Jesús; García-Fontana, Cristina; Silva-Jiménez, Hortencia; Rico-Jiménez, Miriam; Lugo, Andrés Corral; Darias, José Antonio Reyes; Ramos, Juan-Luis

2014-01-01

162

Logarithmic diagrams and gran-curves as an aid in potentiometric titrations in complexometry.  

PubMed

A detailed exposition is given of the use of logarithmic diagrams and Gran plots to construct titration curves and to determine accurately the equivalence point in potentiometric complexometric titrations. PMID:18961242

Johansson, A

1973-01-01

163

Role of titratable acidity in acid aerosol-induced bronchoconstriction  

SciTech Connect

We evaluated the importance of pH, titratable acidity, and specific chemical composition in acid aerosol-induced bronchoconstriction in 8 asthmatic subjects. We administered aerosols of HCl and H/sub 2/SO/sub 4/ at pH 2.0 in an unbuffered state and buffered with glycine. The buffered acids were given in order of increasing titratable acidity (defined as the number of ml of 1 N NaOH required to neutralize 100 ml of acid solution to pH 7.0). Each set of buffered or unbuffered acid aerosols was given on a separate day and each aerosol was inhaled through a mouthpiece during 3 min of tidal breathing. Bronchoconstriction was assessed by measurement of specific airway resistance (SRaw) before and after inhalation of each aerosol. SRaw increased by more than 50% above baseline in 1 of 8 subjects after inhalation of unbuffered HCl and in no subjects after inhalation of unbuffered H/sub 2/SO/sub 4/, even at pH 2.0. In contrast, SRaw increased by greater than 50% in all 8 subjects after inhalation of HCl and glycine at pH 2.0 and 7 of 8 subjects after inhalation of H/sub 2/SO/sub 4/ and glycine at pH 2.0. The mean titratable acidity required to increase SRaw by 50% above baseline was calculated for each challenge by linear interpolation; these values for H/sub 2/SO/sub 4/ and glycine (5.1 ml of 1 N NaOH) and HCl and glycine (2.2 ml of 1 N NaOH) were slightly, but significantly, different (p = 0.01) and were considerably higher than the titratable acidity of the unbuffered acids at pH 2 (1.0 ml of 1 N NaOH).

Fine, J.M.; Gordon, T.; Thompson, J.E.; Sheppard, D.

1987-04-01

164

Potentiometric titrations of rutile suspensions to 250 C  

SciTech Connect

A stirred hydrogen electrode concentration cell was used to conduct potentiometric titrations of rutile suspensions from 25 to 250 C in NaCl and tetramethylammonium chloride media (0.03 to 1.1 m). Hydrothermal pretreatment of the rutile improved titration reproducibility, decreased titration hysteresis, and facilitated determination of the point of zero net proton charge (pHznpc). These pHznpc values are 5.4, 5.1, 4.7, 4.4, 4.3 ({+-} 0.2 pH units), and 4.2 ({+-} 0.3 pH units) at 25, 50, 100, 150, 200, and 250 C, respectively. The difference between these pHznpc values and 1/2 pK{sub w} (the neutral pH of water) is rather constant between 25 and 250 C ({minus} 1.45 {+-} 0.2). This constancy is useful for predictive purposes and, more fundamentally, may reflect similarities between the hydration behavior of surface hydroxyl groups and water. A three-layer, 1pKa surface complexation model with three adjustable parameters (two capacitance values and one counterion binding constant) adequately described all titration data. The most apparent trend in these data for pH values greater than the pHznpc was the increase in proton release (negative surface charge) with increasing temperature. This reflects more efficient screening by Na{sup +} relative to Cl{sup {minus}}. Replacing Na{sup +} with the larger tetramethylammonium cation for some conditions resulted in decreased proton release due to the less efficient screening of negative surface charge by this larger cation.

Machesky, M.L. [Illinois State Water Survey, Champaign, IL (United States)] [Illinois State Water Survey, Champaign, IL (United States); Wesolowski, D.J.; Palmer, D.A. [Oak Ridge National Lab., TN (United States). Chemical and Analytical Sciences Div.] [Oak Ridge National Lab., TN (United States). Chemical and Analytical Sciences Div.; Ichiro-Hayashi, Ken [Tohoku Univ., Sendai (Japan). Inst. of Mineralogy, Petrology and Economic Geology] [Tohoku Univ., Sendai (Japan). Inst. of Mineralogy, Petrology and Economic Geology

1998-04-15

165

Determination of berkelium by the method of spectrophotometric titration  

Microsoft Academic Search

The method that the authors propose consists of the following: berkelium is oxidized electrochemically, spectrophotometric titration of berkelium(IV) by a solution of the reducing agent is performed, and the amount of berkelium(IV) is determined according to the volume of the titrant, and considering the degree of oxidation of berkelium(III) to berkelium(IV), the total berkelium content in the sample is also

L. M. Frolova; V. M. Vityutnev; V. M. Vasilev

1987-01-01

166

Suspension culture titration: A simple method for measuring baculovirus titers.  

PubMed

The baculovirus-insect cell expression system is an important technology for the production of recombinant proteins and baculovirus-based biopesticides. Budded virus titration is critical when scaling up baculovirus production processes in suspension cultures, to ensure reproducible infections, especially when a low multiplicity of infection (MOI) is applied. In this study, a simple suspension culture titration (SCT) assay was developed that involves accurate measurements of the initial cell densities (ICDs) and peak cell densities (PCDs) of an infected culture, from which the MOI and hence the virus inoculum infectious titer can be estimated, using the established Power-Nielsen baculovirus infection model. The SCT assay was assessed in parallel with two adherent culture-based assays (MTT and AlamarBlue) for the Heliothine baculovirus HaSNPV, and was shown to be more objective, time-efficient and reproducible. The model predicted a linear correlation between log(PCD/ICD) and log(MOI), hence an alternative model-independent SCT assay was also developed, which relies on a well-replicated standard curve relating suspension culture-derived PCD/ICD ratios with plaque or endpoint assay-derived MOIs. Standard curves with excellent linearity were generated for HaSNPV and the industrially significant rAcMNPV, demonstrating the feasibility of this simple titration approach, especially in terms of its applicability to a wide range of virus infection kinetics. PMID:22561639

Matindoost, Leila; Chan, Leslie C L; Qi, Ying Mei; Nielsen, Lars K; Reid, Steven

2012-08-01

167

Generalized theory for two-phase ion-pair and complexometric titrations  

Microsoft Academic Search

For the two-phase titration based on ion-pair and metal-complex formation full attention is given to side reactions in both phases. Their significance for the applicability of this type of titration is evaluated. Side reactions in the aqueous phase diminish and in the organic phase promote the ‘titratability’. Equations for the calculation of the side reaction coefficients, the titration curve and

A. Bult; H. A. Dingjan; S. M. Dreijer-van der Glas; W. P. Van Bennekom

1985-01-01

168

Monitoring the photometric behavior of OmegaCAM with Astro-WISE  

NASA Astrophysics Data System (ADS)

The OmegaCAM wide-field optical imager is the sole instrument on the VLT Survey Telescope at ESO's Paranal Observatory. The instrument, as well as the telescope, have been designed for surveys with very good, natural seeing-limited image quality over a 1 square degree field. OmegaCAM was commissioned in 2011 and has been observing three ESO Public Surveys in parallel since October 15, 2011. We use the Astro-WISE information system to monitor the calibration of the observatory and to produce the Kilo Degree Survey (KiDS). Here we describe the photometric monitoring procedures in Astro-WISE and give a first impression of OmegaCAM's photometric behavior as a function of time. The long-term monitoring of the observatory goes hand in hand with the KiDS survey production in Astro-WISE. KiDS is observed under partially non-photometric conditions. Based on the first year of OmegaCAM operations it is expected that a ˜ 1-2 % photometric homogeneity will be achieved for KiDS.

Verdoes Kleijn, G. A.; Kuijken, K. H.; Valentijn, E. A.; Boxhoorn, D. R.; Begeman, K. G.; Deul, E. R.; Helmich, E. M.; Rengelink, R.

2013-01-01

169

The Acid-Base Titration of a Very Weak Acid: Boric Acid  

ERIC Educational Resources Information Center

A laboratory experiment based on the titration of boric acid with strong base in the presence of d-mannitol is described. Boric acid is a very weak acid and direct titration with NaOH is not possible. An auxiliary reagent that contributes to the release of protons in a known stoichiometry facilitates the acid-base titration. Students obtain the…

Celeste, M.; Azevedo, C.; Cavaleiro, Ana M. V.

2012-01-01

170

Semi-supervised learning for photometric supernova classification  

NASA Astrophysics Data System (ADS)

We present a semi-supervised method for photometric supernova typing. Our approach is to first use the non-linear dimension reduction technique diffusion map to detect structure in a data base of supernova light curves and subsequently employ random forest classification on a spectroscopically confirmed training set to learn a model that can predict the type of each newly observed supernova. We demonstrate that this is an effective method for supernova typing. As supernova numbers increase, our semi-supervised method efficiently utilizes this information to improve classification, a property not enjoyed by template-based methods. Applied to supernova data simulated by Kessler et al. to mimic those of the Dark Energy Survey, our methods achieve (cross-validated) 95 per cent Type Ia purity and 87 per cent Type Ia efficiency on the spectroscopic sample, but only 50 per cent Type Ia purity and 50 per cent efficiency on the photometric sample due to their spectroscopic follow-up strategy. To improve the performance on the photometric sample, we search for better spectroscopic follow-up procedures by studying the sensitivity of our machine-learned supernova classification on the specific strategy used to obtain training sets. With a fixed amount of spectroscopic follow-up time, we find that, despite collecting data on a smaller number of supernovae, deeper magnitude-limited spectroscopic surveys are better for producing training sets. For supernova Ia (II-P) typing, we obtain a 44 per cent (1 per cent) increase in purity to 72 per cent (87 per cent) and 30 per cent (162 per cent) increase in efficiency to 65 per cent (84 per cent) of the sample using a 25th (24.5th) magnitude-limited survey instead of the shallower spectroscopic sample used in the original simulations. When redshift information is available, we incorporate it into our analysis using a novel method of altering the diffusion map representation of the supernovae. Incorporating host redshifts leads to a 5 per cent improvement in Type Ia purity and 13 per cent improvement in Type Ia efficiency. A web service for the supernova classification method used in this paper can be found at .

Richards, Joseph W.; Homrighausen, Darren; Freeman, Peter E.; Schafer, Chad M.; Poznanski, Dovi

2012-01-01

171

Phoebe: Albedo Map and Photometric Properties  

NASA Astrophysics Data System (ADS)

Using clear-filter images from Voyager 2 (effective wavelength 0.48 ?m), we have constructed the first-ever digital albedo map of Saturn's moon Phoebe. Most normal reflectances in this new map are between 0.07 and 0.11; the albedo histogram is largely bimodal, suggesting that the satellite is covered predominantly by two different types of surface materials. The highest albedos are confined to isolated, quasi-circular spots 40 to 100 km across, including three spots of varying albedo in a band immediately south of the equator and one especially bright spot at latitude 60°N (normal reflectance as high as 0.13, ?50% brighter than the average surface). The bright northern spot and the brightest of the southern spots occur at approximately the same longitude, an alignment that gives Phoebe its significant rotational lightcurve. The low resolution of the Voyager images does not permit interpretation of the bright spots' origin. Phoebe's global-average photometric function was determined by combining the satellite's telescopic near-opposition phase curve (S. Kruse et al.1986, Icarus68, 168-175) with absolute disk-resolved reflectances measured from the Voyager images (triaxial-ellipsoid shape assumed with radii 115, 110, and 105 km). Modeling of the telescopic observations supports the presence of a significant opposition surge, although scatter in the data does not allow unambiguous determination of the surge's exact strength. The derived photometric function is consistent with the idea that Phoebe is a C-type object—probably a primitive, captured body related to Chiron, Pholus, and the inhabitants of the Kuiper Belt. The albedo map and photometric information will aid in the planning of high-resolution Cassini images of Phoebe, which will represent our first close look at this class of primitive outer Solar-System object.

Simonelli, Damon P.; Kay, Jennifer; Adinolfi, Daniel; Veverka, Joseph; Thomas, Peter C.; Helfenstein, Paul

1999-04-01

172

Atmospheric Emissions Photometric Imaging (AEPI) experiment  

NASA Technical Reports Server (NTRS)

Space plasma physics will be studied on the Atmospheric Laboratory for Applications and Science (ATLAS 1) NASA mission during the Atmospheric Emissions Photometric Imaging (AEPI) experiment. The basic scientific objective of the AEPI is the investigation of the upper atmosphere-ionosphere and the space shuttle environment. The experiment areas of the AEPI include: (1) the investigation of ionospheric transport processes by observing Mg(+) ions; (2) studies of optical properties of artificially induced electron beams; (3) measurement of electron cross sections for selected atmospheric species; (4) studies of natural airglow; and (5) studies of natural auroras. On ATLAS 1, optical emissions generated by the shuttle (shuttle ram glow) will also be investigated.

Mende, S. B.

1988-01-01

173

Photometric Redshifts for Galaxies in the GOODS Southern Field  

Microsoft Academic Search

We use extensive multiwavelength photometric data from the Great Observatories Origins Deep Survey to estimate photometric redshifts for a sample of 434 galaxies with spectroscopic redshifts in the Chandra Deep Field-South. Using the Bayesian method, which incorporates redshift\\/magnitude priors, we estimate photometric redshifts for galaxies in the range 18

B. Mobasher; R. Idzi; N. Benítez; A. Cimatti; S. Cristiani; E. Daddi; T. Dahlen; M. Dickinson; T. Erben; H. C. Ferguson; M. Giavalisco; N. A. Grogin; A. M. Koekemoer; M. Mignoli; L. A. Moustakas; M. Nonino; P. Rosati; M. Schirmer; D. Stern; E. Vanzella; C. Wolf; G. Zamorani; STScI; Osservatorio Astrofisico di Bologna

2004-01-01

174

Characterization of Sea Lettuce Surface Functional Groups by Potentiometric Titrations  

NASA Astrophysics Data System (ADS)

In pursuit of our ultimate goal to better understand the prodigious capacity of the marine macroalga Ulva lactuca (sea lettuce) for adsorbing a broad range of dissolved trace metals from seawater, we performed an initial characterization of its surface functional groups. Specifically, the number of distinct functional groups as well as their individual bulk concentrations and acid dissociation constants (pKas) were determined by potentiometric titrations in NaCl solutions of various ionic strengths (I = 0.01-5.0 M), under inert nitrogen atmosphere at 25°C. Depending on the ionic strength, Ulva samples were manually titrated down to pH 2 or 3 with 1 N HCl and then up to pH 10 with 1 N NaOH in steps of 0.1-0.2 units, continuously monitoring pH with a glass combination electrode. Titrations of a dehydrated Ulva standard reference material (BCR-279) were compared with fresh Ulva tissue cultured in our laboratory. A titration in filtered natural seawater was also compared with one in an NaCl solution of equal ionic strength. Equilibrium constants for the ionization of water in NaCl solutions as a function of ionic strength were obtained from the literature. Fits to the titration data ([H]T vs. pH) were performed with the FITEQL4.0 computer code using non-electrostatic 3-, 4-, and 5-site models, either by fixing ionic strength at its experimental value or by allowing it to be extrapolated to zero, while considering all functional group pKas and bulk concentrations as adjustable parameters. Since pKas and bulk concentrations were found to be strongly correlated, the latter were also fixed in some cases to further constrain the pKas. Whereas these calculations are currently ongoing, preliminary results point to three, possibly four, functional groups with pKas of about 4.1, 6.3, and 9.5 at I = 0. Bulk concentrations of the three groups are very similar, about 5-6×10-4 mol/g based on dry weight, which suggests that all are homogeneously distributed over the surface and probably part of a single macromolecular scaffold. Fresh Ulva tissue appears to contain the same three functional groups but at lower concentrations, based on wet weight. The titration in natural seawater was largely dominated by the non-carbonate alkalinity of the solution and could not be robustly modeled. Results of fits with ionic strengths fixed at their experimental values indicate that the pKas of all three groups display prominent Debije-Hückel-type behavior, hence that these acid dissociation reactions involve a different mechanism than metal-proton exchange reactions on mineral surfaces, whose distribution coefficients (i.e., equilibrium constants) generally show a weak ionic strength dependence.

Ebling, A. M.; Schijf, J.

2008-12-01

175

Upper airway surgery: the effect on nasal continuous positive airway pressure titration on obstructive sleep apnea patients.  

PubMed

The objective of this study was to observe the change in CPAP pressure after nasal and/or tonsil surgery in a retrospective study involving 17 patients unable to tolerate CPAP titration. All patients had two polysomnography studies for titration: one before and another subsequent to upper airway surgical treatment. The results showed a mean age of 49 +/- 9 years, a body mass index of 30 +/- 4 kg/m(2) and an apnea-hypopnea index of 38 +/- 19. Surgical procedures were radiofrequency reduction of the inferior turbinate (eight patients), septoplasty (one patient), septoplasty with inferior turbinectomy (two patients), septoplasty with inferior turbinate submucosal diathermy (two patients), septoplasty with tonsillectomy (two patients), septoplasty with inferior turbinate submucosal diathermy and tonsillectomy (one patient) and tonsillectomy (one patient). CPAP titration before and after surgery had respectively a mean pressure of 12.4 +/- 2.5 and 10.2 +/- 2.2 cmH(2)O ( P = 0.001). Maximum CPAP pressure was 16.4 cmH(2)O before and 13 cmH(2)O after surgery. A pressure reduction > or =1 cmH(2)O occurred in 76.5% of the patients and > or =3 cmH(2)O in 41.1%. Upper airway surgical treatment appears to have some benefit by reducing nasal CPAP pressure levels. The effect seems to be greater when the prior pressure was > or =14 cmH(2)O. PMID:16450157

Zonato, Adriane Iurck; Bittencourt, Lia Rita A; Martinho, Fernanda Louise; Gregório, Luiz Carlos; Tufik, Sergio

2006-05-01

176

Applications of Isothermal Titration Calorimetry in RNA Biochemistry and Biophysics  

PubMed Central

Isothermal titration calorimetry (ITC) has been applied to the study of proteins for many years. Its use in the biophysical analysis of RNAs has lagged significantly behind its use in protein biochemistry, however, in part because of the relatively large samples required. As the instrumentation has become more sensitive, the ability to obtain high quality data on RNA folding and RNA ligand interactions has improved dramatically. This review provides an overview of the ITC experiment and describes recent work on RNA systems that have taken advantage of its versatility for the study of small molecule binding, protein binding, and the analysis of RNA folding.

Feig, Andrew L.

2008-01-01

177

Photometric Evolution of Dusty Starburst Galaxies  

NASA Astrophysics Data System (ADS)

By performing N-body simulations of chemodynamical evolution of galaxies with dusty starbursts, we investigate photometric evolution of gas-rich major mergers in order to explore the nature of ultraluminous infrared galaxies (ULIRGs) with the total infrared luminosity (L IR for 8 ˜ 1000 ?m) of ˜ 1012 L?. Main results are the following five. (1) Global colors and absolute magnitudes the during dusty starburst of a major merger do not change with time significantly. (2) Dust extinction of stellar populations in a galaxy merger with large infrared luminosity (LIR > 1011 L?) is selective in the sense that younger stellar populations are preferentially obscured by dust than old ones. (3) LIR, the ratio of LIR to LB and the dust temperature Tdust increase with the increase of the star formation rate. (4) The star formation efficiency, total gas mass, the degree of dust extinction (AV), Tdust, LIR, and LIR/LB depend strongly on the separation of two cores of the merger. (5) The two-dimensional distribution of global colors (e.g., R-K) shows a negative color gradient during starburst. Our numerical results clearly demonstrate that dynamical processes of major galaxy merging, which can control the time evolution of the relative spatial distribution of dusty interstellar gas and young stars, play a vital role in determining photometric properties of ULIRGs.

Shioya, Yasuhiro

2004-02-01

178

Photometric Stellar Variability at the Galactic Center  

NASA Astrophysics Data System (ADS)

This study investigates the photometric variability of the stellar population at the central 10?? × 10?? of our Galaxy. 18 data sets from July 2005 to May 2012 are used, and all come from the W. M. Keck II 10 m telescope using Laser Guide Star Adaptive Optics (only one epoch uses a Natural Guide Star). Overall, the light curves of 1,949 stars are tested for variability with a photometric accuracy of ~5%. Of these, 235 stars were identified as likely variable, and 3 stars showed a periodic behavior with all of them having a period of ~3 years (the study is sensitive to periods between 1 and 4 years). All 3 stars lie outside a radius of 4?? from the central black hole and are likely to be late-type giants. The shape of the light curves is near sinusoidal which seems to make an eclipsing binary an unlikely interpretation. Long-period variable stars like Mira variables are an alternative hypothesis, however, the periods of >3 years seem uncharacteristically long.

Kelley, Michelle; Ghez, A. M.; Meyer, L.; Phifer, K. A.; REU Program, UCLA

2013-01-01

179

Charge characteristics of humic and fulvic acids: comparative analysis by colloid titration and potentiometric titration with continuous pK-distribution function model.  

PubMed

Charge characteristics of humic and fulvic acids of a different origin (inshore soils, peat, marine sediments, and soil (lysimetric) waters) were evaluated by means of two alternative methods - colloid titration and potentiometric titration. In order to elucidate possible limitations of the colloid titration as an express method of analysis of low content of humic substances we monitored changes in acid-base properties and charge densities of humic substances with soil depth, fractionation, and origin. We have shown that both factors - strength of acidic groups and molecular weight distribution in humic and fulvic acids - can affect the reliability of colloid titration. Due to deviations from 1:1 stoichiometry in interactions of humic substances with polymeric cationic titrant, the colloid titration can underestimate total acidity (charge density) of humic substances with domination of weak acidic functional groups (pK>6) and high content of the fractions with molecular weight below 1kDa. PMID:18657293

Bratskaya, S; Golikov, A; Lutsenko, T; Nesterova, O; Dudarchik, V

2008-09-01

180

A study of statistical error in isothermal titration calorimetry.  

PubMed

In isothermal titration calorimetry (ITC), the two main sources of random (statistical) error are associated with the extraction of the heat q from the measured temperature changes and with the delivery of metered volumes of titrant. The former leads to uncertainty that is approximately constant and the latter to uncertainty that is proportional to q. The role of these errors in the analysis of ITC data by nonlinear least squares is examined for the case of 1:1 binding, M+X right arrow over left arrow MX. The standard errors in the key parameters-the equilibrium constant Ko and the enthalpy DeltaHo-are assessed from the variance-covariance matrix computed for exactly fitting data. Monte Carlo calculations confirm that these "exact" estimates will normally suffice and show further that neglect of weights in the nonlinear fitting can result in significant loss of efficiency. The effects of the titrant volume error are strongly dependent on assumptions about the nature of this error: If it is random in the integral volume instead of the differential volume, correlated least-squares is required for proper analysis, and the parameter standard errors decrease with increasing number of titration steps rather than increase. PMID:12963058

Tellinghuisen, Joel

2003-10-01

181

Common Standards of Basal Insulin Titration in T2DM  

PubMed Central

Type 2 diabetes mellitus has become a worldwide major health problem, and the number of people affected is steadily increasing. Thus, not all patients suffering from the disease can be treated by specialized diabetes centers or outpatient clinics, but by primary care physicians. The latter, however, might have time constraints and have to deal with many kinds of diseases or with multimorbid patients, so their focus is not so much on lowering high blood glucose values. Thus, the physicians, as well as the patients themselves, are often reluctant to initiate and adjust insulin therapy, although basal insulin therapy is considered the appropriate strategy after oral antidiabetic drug failure, according to the latest international guidelines. A substantial number of clinical studies have shown that insulin initiation and optimization can be managed successfully by using titration algorithms—even in cases where patients themselves are the drivers of insulin titration. Nevertheless, tools and strategies are needed to facilitate this process in the daily life of both primary health care professionals and patients with diabetes.

Arnolds, Sabine; Heise, Tim; Flacke, Frank; Sieber, Jochen

2013-01-01

182

Determination of berkelium by the method of spectrophotometric titration  

SciTech Connect

The method that the authors propose consists of the following: berkelium is oxidized electrochemically, spectrophotometric titration of berkelium(IV) by a solution of the reducing agent is performed, and the amount of berkelium(IV) is determined according to the volume of the titrant, and considering the degree of oxidation of berkelium(III) to berkelium(IV), the total berkelium content in the sample is also determined. In this case the necessity for preliminary determination of the molar extinction coefficient of berkelium(IV) under the experimental conditions falls away. Moreover, the radiometric method of determining the berkelium content is not used. Successful titration requires selection of a reagent which, on the one hand, would rapidly reduce berkelium(VI), but on the other hand, neither itself nor the reaction products would interfere with the measurement of the optical density of berkelium(IV). As is well known, berkelium(IV) is quantitatively and rapidly reduced by hydrogen peroxide (10, 11), hydroxylamine (11), and nitrous acid (9). After preliminary experiments, they selected hydrogen peroxide and sodium nitrite as the titrants.

Frolova, L.M.; Vityutnev, V.M.; Vasil'ev, V.M.

1987-01-01

183

In silico concurrent multisite pH titration in proteins.  

PubMed

The concurrent proton binding at multiple sites in macromolecules such as proteins and nucleic acids is an important yet challenging problem in biochemistry. We develop an efficient generalized Hamiltonian approach to attack this issue. Based on the previously developed generalized-ensemble methods, an effective potential energy is constructed which combines the contributions of all (relevant) protonation states of the molecule. The effective potential preserves important phase regions of all states and, thus, allows efficient sampling of these regions in one simulation. The need for intermediate states in alchemical free energy simulations is greatly reduced. Free energy differences between different protonation states can be determined accurately and enable one to construct the grand canonical partition function. Therefore, the complicated concurrent multisite proton titration process of protein molecules can be satisfactorily simulated. Application of this method to the simulation of the pKa of Glu49, Asp50, and C-terminus of bovine pancreatic trypsin inhibitor shows reasonably good agreement with published experimental work. This method provides an unprecedented vivid picture of how different protonation states change their relative population upon pH titration. We believe that the method will be very useful in deciphering the molecular mechanism of pH-dependent biomolecular processes in terms of a detailed atomistic description. © 2014 Wiley Periodicals, Inc. PMID:24889139

Hu, Hao; Shen, Lin

2014-07-30

184

A novel approach for high precision rapid potentiometric titrations: application to hydrazine assay.  

PubMed

We propose a high precision rapid personal computer (PC) based potentiometric titration technique using a specially designed mini-cell to carry out redox titrations for assay of chemicals in quality control laboratories attached to industrial, R&D, and nuclear establishments. Using this technique a few microlitre of sample (50-100 ?l) in a total volume of ~2 ml solution can be titrated and the waste generated after titration is extremely low comparing to that obtained from the conventional titration technique. The entire titration including online data acquisition followed by immediate offline analysis of data to get information about concentration of unknown sample is completed within a couple of minutes (about 2 min). This facility has been created using a new class of sensors, viz., pulsating sensors developed in-house. The basic concept in designing such instrument and the salient features of the titration device are presented in this paper. The performance of the titration facility was examined by conducting some of the high resolution redox titrations using dilute solutions--hydrazine against KIO(3) in HCl medium, Fe(II) against Ce(IV) and uranium using Davies-Gray method. The precision of titrations using this innovative approach lies between 0.048% and 1.0% relative standard deviation in different redox titrations. With the evolution of this rapid PC based titrator it was possible to develop a simple but high precision potentiometric titration technique for quick determination of hydrazine in nuclear fuel dissolver solution in the context of reprocessing of spent nuclear fuel in fast breeder reactors. PMID:22128994

Sahoo, P; Malathi, N; Ananthanarayanan, R; Praveen, K; Murali, N

2011-11-01

185

Improved Specularity Detection relying on a Photometric Stereo Technique  

Microsoft Academic Search

This paper introduces an improved algorithm for detecting specularity using photometric stereo technique. While three images are enough for recovering surface heights, additional image may be used for detecting specularity. Therefore a four-source photometric stereo system was built for the purpose of this study. If specularity exists in one of the images, the intensity value from this image will elevate

A. El Gend; A. Shalaby

2006-01-01

186

Photometric Analysis in the Kepler Science Operations Center Pipeline.  

National Technical Information Service (NTIS)

We describe the Photometric Analysis (PA) software component and its context in the Kepler Science Operations Center (SOC) pipeline. The primary tasks of this module are to compute the photometric flux and photocenters (centroids) for over 160,000 long ca...

B. D. Clarke F. Girouard H. Wu J. D. Twicken J. M. Jenkins P. Tenenbaum S. T. Bryson T. C. Klaus

2010-01-01

187

Photometric analysis in the Kepler Science Operations Center pipeline  

Microsoft Academic Search

We describe the Photometric Analysis (PA) software component and its context in the Kepler Science Operations Center (SOC) Science Processing Pipeline. The primary tasks of this module are to compute the photometric flux and photocenters (centroids) for over 160,000 long cadence (~thirty minute) and 512 short cadence (~one minute) stellar targets from the calibrated pixels in their respective apertures. We

Joseph D. Twicken; Bruce D. Clarke; Stephen T. Bryson; Peter Tenenbaum; Hayley Wu; Jon M. Jenkins; Forrest Girouard; Todd C. Klaus

2010-01-01

188

Measuring magnification bias in photometric galaxy surveys  

NASA Astrophysics Data System (ADS)

In this contribution, we analyze how cosmic magnification may be detected in upcoming large photometric galaxy surveys and how some systematic effects can affect it. Magnification manifests itself as an enhancement or decrease of galaxy/quasar number counts at very high redshifts due to the magnifying weak lensing effect of intervening matter in the line of sight. It usually shows up in observations as a correlation or anti-correlation at low angular scales in the cross-correlation function. Its amplitude is directly related to the galaxy bias and cosmological parameters. We focus on three particular systematics and we are carrying out this study in the context of the Dark Energy Survey (DES) that will cover 5000 square degrees and reach i_{AB}<24 making measurements up to z?1.4 with a photo-z resolution of 0.03(1+z).

Ponce, R.; Sánchez, E.; Sevilla, I.

2013-05-01

189

uvby? photometric catalog toward Anticenter (Monguio+, 2013)  

NASA Astrophysics Data System (ADS)

A uvbyH? Stromgren photometric survey covering 16sq.deg in the anticenter direction was carried out using the Wide Field Camera (WFC) at the Isaac Newton Telescope (INT), with a typical seeing of 1-1.5". Data from three different observing runs (2009A, 2010B, 2011A) were used for the catalog. The calibration to the standard system was undertaken using open clusters. A main catalog of 35974 stars with all Stromgren indexes, and a more extended one with 96980 stars with partial data. The central 8sq.deg have a limiting magnitude of V=17mag while the outer region reaches V=15.5mag. Two catalogs are available, the first one with the final mean values and a second one with all the individual measurements for each star. (2 data files).

Monguio, M.; Figueras, F.; Grosbol, P.

2012-11-01

190

Photometric Variability of Magnetic White Dwarfs  

NASA Astrophysics Data System (ADS)

We present our survey results searching for photometric variability and rotation periods of 77 magnetic white dwarfs (MWDs). The sample consists of 24 bright (V < 16), isolated MWDs and 53 MWDs (r' < 18.5) discovered spectroscopically by SDSS. Observations were taken with the 2.5 m Isaac Newton Telescope, La Palma. We determine well-defined periods for 12 stars (16% of the sample) and variability but with poorly constrained periods in a further 13 targets (17%). A period of 7.72 days is found for LHS 5064, the second longest measured for an isolated MWD. Where periods of variability have been determined, the magnetic field strength, temperature, mass and age of the white dwarf have been compared to determine whether any physically interesting correlations emerge.

Lawrie, K. A.; Burleigh, M. R.; Brinkworth, C. S.; Marsh, T. R.; Hodgkin, S. T.; Baker, D. E. A.; Cossins, P.; Littlejohns, O. M.; Scott, A. E.; Steele, P. R.

2013-01-01

191

Standard Stars for the BYU ? Photometric System  

NASA Astrophysics Data System (ADS)

We present our list of primary standard stars for the BYU ? photometric system. This system is similar to the ? photometric system that is frequently used in conjunction with the intermediate band uvby system. Both systems use the difference between magnitudes measured in a wide (15-20-nm) and narrow (3-nm) bandpass centered on one of the strong Balmer lines of hydrogen to establish a temperature sensitive color index. Line indices formed in this manner are independent of atmospheric extinction and interstellar reddening. The present list of standard stars for the BYU system was established using spectroscopic observations that fully cover the region between H-? and H- ?. Color indices were established using synthetic photometry reductions to convolve ideal filter profiles with the observed spectra. Typical numbers of observations per star is in excess of 20 with some stars having been observed more than 60 times over five years. The typical error per observation for the standards is on the order of 1-3 mmag. Complete information for each star is provided in the tables for this presentation. In addition to the standard field stars, we present ? and ? observations of individual stars that are members of selected open clusters. These include the Hyades, Pleiades, Coma, and NGC 752 clusters. These stars fit the same main sequence plot as has been found for the standard field stars in the ?-? plane. Stars that exhibit varying degrees of hydrogen emission are easily noticed in an ?-? plot. We have found that candidates for emission line objects, high mass x-ray binaries, and young stellar objects are readily identified in our color-color plots. We acknowledge continued support from the BYU College of Physical and Mathematical Sciences as well as partial support from NSF Grant AST #0618209. We also thank the Dominion Astrophysical Observatory for continued allocation of robotic observing time for spectroscopy on the 1.2-m telescope.

Joner, Michael D.; Hintz, E. G.

2013-01-01

192

ASTEP South: a first photometric analysis  

NASA Astrophysics Data System (ADS)

The ASTEP project aims at detecting and characterizing transiting planets from Dome C, Antarctica, and qualifying this site for photometry in the visible. The first phase of the project, ASTEP South, is a fixed 10 cm diameter instrument pointing continuously towards the celestial South Pole. Observations were made almost continuously during 4 winters, from 2008 to 2011. The point-to-point RMS of 1-day photometric lightcurves can be explained by a combination of expected statistical noises, dominated by the photon noise up to magnitude 14. This RMS is large, from 2.5 mmag at R = 8 to 6% at R = 14, because of the small size of ASTEP South and the short exposure time (30 s). Statistical noises should be considerably reduced using the large amount of collected data. A 9.9-day period eclipsing binary is detected, with a magnitude R = 9.85. The 2-season lightcurve folded in phase and binned into 1,000 points has a RMS of 1.09 mmag, for an expected photon noise of 0.29 mmag. The use of the 4 seasons of data with a better detrending algorithm should yield a sub-millimagnitude precision for this folded lightcurve. Radial velocity follow-up observations reveal a F-M binary system. The detection of this 9.9-day period system with a small instrument such as ASTEP South and the precision of the folded lightcurve show the quality of Dome C for continuous photometric observations, and its potential for the detection of planets with orbital periods longer than those usually detected from the ground.

Crouzet, N.; Guillot, T.; Mékarnia, D.; Szulágyi, J.; Abe, L.; Agabi, A.; Fanteï-Caujolle, Y.; Gonçalves, I.; Barbieri, M.; Schmider, F.-X.; Rivet, J.-P.; Bondoux, E.; Challita, Z.; Pouzenc, C.; Fressin, F.; Valbousquet, F.; Blazit, A.; Bonhomme, S.; Daban, J.-B.; Gouvret, C.; Bayliss, D.; Zhou, G.

2013-01-01

193

Photometric Properties of Enceladus' South Polar Terrain  

NASA Astrophysics Data System (ADS)

Cassini images reveal in exquisite detail the complex and varied terrains within the geologically active south pole of Enceladus. The region is dominated by four parallel rifts or sulci, informally known as tiger stripes, from which plumes comprised primarily of water vapor erupt [1,2]. The rich data set of Cassini images acquired at high spatial resolution (< 0.5 km/pixel) and a variety of viewing and illumination geometries enables the quantitative analysis of surface scattering properties through disk-resolved photometry. Here we investigate the photometric properties of individual terrain units [3] through fits of the Hapke photometric model [4] to data acquired in the clear (CL1 CL2), UV3, GRN, and IR3 filters, centered at 0.61, 0.34, 0.57, and 0.93 ?m, respectively. Terrain units include the tiger stripe smooth and platy plank formations, tiger stripe medial dorsum structures, relict tiger stripe structures, south pole funiscular (ropy) plains, south pole lateral fold-and-wedge formations, and the south pole reticulated plains. Despite the constant, ubiquitous infall of plume particles onto the surface, differences in scattering properties, texture, and albedo among terrain units can be discerned. Work supported by NASA's Cassini Data Analysis Program. [1] Porco et al. 2006 Science 311, 1393-1401. [2] Hansen et al. 2008 Nature 456, 477-479. [3] Spencer et al. 2009 in Saturn from Cassini-Huygens (M. K. Dougherty et al. Eds.) 683-724. [4] Hapke 2002 Icarus 157, 523-534.

Annex, Andrew; Verbiscer, A. J.; Helfenstein, P.

2012-10-01

194

Signal processing with a summing operational amplifier in multicomponent potentiometric titrations.  

PubMed

It has been proved that application of two indicator electrodes connected to the ordinary titration apparatus through an auxiliary electronic device (a summing operational amplifier) significantly extends the scope of multicomponent potentiometric titrations in which the analytes are determined simultaneously from a single titration curve. For each analyte there is a corresponding potential jump on the titration curve. By application of the proposed auxiliary device, the sum of the electrode potentials is measured. The device also enables the relative sizes of the potential jumps at the end-points on the titration curve to be varied. The advantages of the proposed signal processing are exemplified by complexometric potentiometric titrations of Fe(III) and Cu(II) in mixtures, with a platinum electrode and a copper ion-selective electrode as the indicator electrodes. PMID:18964366

Parczewski, A

1987-06-01

195

Ultrasensitivity by molecular titration in spatially propagating enzymatic reactions.  

PubMed

Delineating design principles of biological systems by reconstitution of purified components offers a platform to gauge the influence of critical physicochemical parameters on minimal biological systems of reduced complexity. Here we unravel the effect of strong reversible inhibitors on the spatiotemporal propagation of enzymatic reactions in a confined environment in vitro. We use micropatterned, enzyme-laden agarose gels which are stamped on polyacrylamide films containing immobilized substrates and reversible inhibitors. Quantitative fluorescence imaging combined with detailed numerical simulations of the reaction-diffusion process reveal that a shallow gradient of enzyme is converted into a steep product gradient by addition of strong inhibitors, consistent with a mathematical model of molecular titration. The results confirm that ultrasensitive and threshold effects at the molecular level can convert a graded input signal to a steep spatial response at macroscopic length scales. PMID:23972857

Semenov, Sergey N; Markvoort, Albert J; Gevers, Wouter B L; Piruska, Aigars; de Greef, Tom F A; Huck, Wilhelm T S

2013-08-20

196

Field-effect based attomole titrations in nanoconfinement.  

PubMed

This paper describes a novel capacitive method to change the pH in micro- and nanofluidic channels. A device with two metal gate electrodes outside an insulating channel wall is used for this purpose. The device is operated at high ionic strength with thin double layers. We demonstrate that gate potentials applied between the electrodes cause a release or uptake of protons from the silicon nitride surface groups, resulting in a pH shift in the channel and a titration of solution compounds present. Due to the high quality silicon nitride insulating layer, the effect is purely capacitive and electrolysis can be neglected. Fluorescein was employed as a fluorescent pH indicator to quantify the induced pH changes, and a maximum change of 1.6 pH units was calculated. A linear relationship was found between applied potential and fluorescein intensity change, indicating a linear relation between actuated proton amount and applied voltage. Since this pH actuation method avoids redox reactions and can be operated at physiological ionic strength, it can be very useful as a "soft" way to change the pH in very small volumes e.g. in bioassays or cell-based research. The sensitivity of the optical detection method poses the only limit to the detectable amount of substance and the observed volume. In a preliminary measurement we show one possible application, namely titration of 100 attomol of TRIS in a 7 pL detection volume. It is important to stress that this pH actuation principle fundamentally differs from the pH changes occurring in ionic transistors which are due to counterion enrichment and coion exclusion, because it does not rely on double-layer overlap. As a result it can be operated at high ionic strength and in channels of up to at least 1 microm height. PMID:20024025

Veenhuis, Rogier B H; van der Wouden, Egbert J; van Nieuwkasteele, Jan W; van den Berg, Albert; Eijkel, Jan C T

2009-12-21

197

QUANTIFYING PHOTOMETRIC REDSHIFT ERRORS IN THE ABSENCE OF SPECTROSCOPIC REDSHIFTS  

SciTech Connect

Much of the science that is made possible by multiwavelength redshift surveys requires the use of photometric redshifts. But as these surveys become more ambitious, and as we seek to perform increasingly accurate measurements, it becomes crucial to take proper account of the photometric redshift uncertainties. Ideally the uncertainties can be directly measured using a comparison with spectroscopic redshifts, but this may yield misleading results since spectroscopic samples are frequently small and not representative of the parent photometric samples. We present a simple and powerful empirical method to constrain photometric redshift uncertainties in the absence of spectroscopic redshifts. Close pairs of galaxies on the sky have a significant probability of being physically associated and therefore of lying at nearly the same redshift. The difference in photometric redshifts in close pairs is therefore a measure of the redshift uncertainty. Some observed close pairs will arise from chance projections along the line of sight, but it is straightforward to perform a statistical correction for this effect. We demonstrate the technique using both simulated data and actual observations, and discuss how its usefulness can be limited by the presence of systematic photometric redshift errors. Finally, we use this technique to show how photometric redshift accuracy can depend on galaxy type.

Quadri, Ryan F.; Williams, Rik J., E-mail: quadri@strw.leidenuniv.n [Leiden Observatory, Leiden University, NL-2300 RA, Leiden (Netherlands)

2010-12-10

198

Galaxy structure searches by photometric redshifts in the CFHTLS  

NASA Astrophysics Data System (ADS)

Context. Counting clusters is one of the methods to constrain cosmological parameters, but has been limited up to now both by the redshift range and by the relatively small sizes of the homogeneously surveyed areas. Aims: In order to enlarge publicly available optical cluster catalogs, in particular at high redshift, we have performed a systematic search for clusters of galaxies in the Canada France Hawaii Telescope Legacy Survey (CFHTLS). Methods: We considered the deep 2, 3 and 4 CFHTLS Deep fields (each 1 × 1 deg2), as well as the wide 1, 3 and 4 CFHTLS Wide fields. We used the Le Phare photometric redshifts for the galaxies detected in these fields with magnitude limits of i'=25 and 23 for the Deep and Wide fields respectively. We then constructed galaxy density maps in photometric redshift bins of 0.1 based on an adaptive kernel technique and detected structures with SExtractor at various detection levels. In order to assess the validity of our cluster detection rates, we applied a similar procedure to galaxies in Millennium simulations. We measured the correlation function of our cluster candidates. We analyzed large scale properties and substructures, including filaments, by applying a minimal spanning tree algorithm both to our data and to the Millennium simulations. Results: We detected 1200 candidate clusters with various masses (minimal masses between 1.0 × 1013 and 5.5 × 1013 and mean masses between 1.3 × 1014 and 12.6 × 1014~M_?) in the CFHTLS Deep and Wide fields, thus notably increasing the number of known high redshift cluster candidates. We found a correlation function for these objects comparable to that obtained for high redshift cluster surveys. We also show that the CFHTLS deep survey is able to trace the large scale structure of the universe up to z ? 1. Our detections are fully consistent with those made in various CFHTLS analyses with other methods. We now need accurate mass determinations of these structures to constrain cosmological parameters. Conclusions: We have shown that a search for galaxy clusters based on density maps built from galaxy catalogs in photometric redshift bins is successful and gives results comparable to or better than those obtained with other methods. By applying this technique to the CFHTLS survey we have increased the number of known optical high redshift cluster candidates by a large factor, an important step towards using cluster counts to measure cosmological parameters. Based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products produced at TERAPIX and the Canadian Astronomy Data Centre as part of the Canada-France-Hawaii Telescope Legacy Survey, a collaborative project of NRC and CNRS.

Adami, C.; Durret, F.; Benoist, C.; Coupon, J.; Mazure, A.; Meneux, B.; Ilbert, O.; Blaizot, J.; Arnouts, S.; Cappi, A.; Garilli, B.; Guennou, L.; Lebrun, V.; Lefèvre, O.; Maurogordato, S.; McCracken, H. J.; Mellier, Y.; Slezak, E.; Tresse, L.; Ulmer, M. P.

2010-01-01

199

Photometric identification of blue horizontal branch stars  

NASA Astrophysics Data System (ADS)

We investigate the performance of some common machine learning techniques in identifying blue horizontal branch (BHB) stars from photometric data. To train the machine learning algorithms, we use previously published spectroscopic identifications of BHB stars from Sloan digital sky survey (SDSS) data. We investigate the performance of three different techniques, namely k nearest neighbour classification, kernel density estimation for discriminant analysis and a support vector machine (SVM). We discuss the performance of the methods in terms of both completeness (what fraction of input BHB stars are successfully returned as BHB stars) and contamination (what fraction of contaminating sources end up in the output BHB sample). We discuss the prospect of trading off these values, achieving lower contamination at the expense of lower completeness, by adjusting probability thresholds for the classification. We also discuss the role of prior probabilities in the classification performance, and we assess via simulations the reliability of the dataset used for training. Overall it seems that no-prior gives the best completeness, but adopting a prior lowers the contamination. We find that the support vector machine generally delivers the lowest contamination for a given level of completeness, and so is our method of choice. Finally, we classify a large sample of SDSS Data Release 7 (DR7) photometry using the SVM trained on the spectroscopic sample. We identify 27 074 probable BHB stars out of a sample of 294 652 stars. We derive photometric parallaxes and demonstrate that our results are reasonable by comparing to known distances for a selection of globular clusters. We attach our classifications, including probabilities, as an electronic table, so that they can be used either directly as a BHB star catalogue, or as priors to a spectroscopic or other classification method. We also provide our final models so that they can be directly applied to new data. Full Tables 7, A.3 and A.4 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/522/A88

Smith, K. W.; Bailer-Jones, C. A. L.; Klement, R. J.; Xue, X. X.

2010-11-01

200

CRISM mapping of surface photometric parameters at MER landing sites  

NASA Astrophysics Data System (ADS)

CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) on-board MRO (Mars Reconnaissance Orbiter) acquires observations under varied geometry conditions in visible/near infrared which can provide constraints on the surface physical properties. The study consists on the estimation of the surface photometric parameters by inverting Hapke's photometric model in a Bayesian framework at Mars Exploration Rover (MER) landing sites (Gusev Crater and Meridiani Planum). We present here one of the 6 photometric parameter map, the single scattering albedo ?, which is related to the composition and the particle size. The map of the parameter ? is estimated at 750 nm with a spatial resolution of 180m/pxl.

Fernando, J.; Schmidt, F.; Pinet, P.; Ceamanos, X.; Douté, S.; Daydou, Y.

2013-09-01

201

Photometric Properties of the Pluto System  

NASA Astrophysics Data System (ADS)

We will present a summary of the current state of knowledge of the photometric properties of the surfaces of the four bodies in the Pluto system. Our understanding of Pluto benefits from the longest running dataset and present-day photometry is especially valuable for tracking and characterizing the current seasonal evolution. In particular, the surface of Pluto has recently been seen to have undergone a global-scale change in color. At the same time the phase coefficient, a tracer for the state of surface texture, remains unchanged. The smaller bodes in the system are somewhat easier objects for study in that they are not expected to exhibit seasonal variability. Charon is known to be compositionally distinct from Pluto and the same is expected for Hydra and Nix. The phase coefficient for Charon has now been shown to differ from Pluto both in degree and in character thus accentuating the differences in surface properties between the two. Information about the newly discovered satellites, Hydra and Nix, is much more sparse but the expectation is that they will more closely resemble Charon in surface properties. Our presentation will include a summary of current properties with a special emphasis on seasonal evolution on Pluto, phase coefficients, lightcurves, and comparisons of surface composition enabled by filter photometry. Also included will be a discussion of future observational plans that will lead up to the New Horizons flyby in 2015. This work has been supported by grants from NASA and STScI.

Buie, Marc W.; Grundy, W. M.; Tholen, D. J.; Stephens, D. C.

2010-10-01

202

Photometric Monitoring of Quasars with Kepler  

NASA Astrophysics Data System (ADS)

We have observed the photometric variability of four flat-spectrum radio quasars, and one radio galaxy (Cyg A) with Kepler, since mid-2010. Kepler’s ability to observe uninterrupted for very extended durations provides a unique opportunity to obtain very long time sequences on active galactic nuclei, something that is hard to do even with dedicated ground-based telescope networks. It allows us to examine these light curves for variability on timescales from hours to weeks, and to probe the physical processes involved in accretion around the central black hole and the organization of some of that energy into jets that ultimately power double-lobed radio sources. Kepler was designed to detect exoplanet transits of stars, and the data analysis pipeline is highly optimized for that purpose. We cannot use the standard analysis tools for the quasi-random variability in quasars, so we re-analysed the raw data, and overcame some of the challenges in calibrating these light curves. We briefly discuss some of the issues in producing calibrated light curves for long timescales. For each quasar we computed power spectra, and found power-law slopes of around -2 for most. Although sensitive to quasi-periodic variations, we did not find any convincing evidence for periodicity in any of our targets. This research was carried out, in part, at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. Copyright 2012. California Institute of Technology. Government sponsorship acknowledged.

Unwin, Stephen C.; Wehrle, A. E.; Wiita, P. J.; Revalski, M.; Silano, D.; Sprague, D.; Di Lorenzo, P.

2013-01-01

203

Broadband Photometric Reverberation Mapping of NGC 4395  

NASA Astrophysics Data System (ADS)

We present results of broadband photometric reverberation mapping (RM) to measure the radius of the broad-line region, and subsequently the black hole mass (M BH), in the nearby, low-luminosity active galactic nuclei NGC 4395. Using the Wise Observatory's 1 m telescope equipped with the Sloan Digital Sky Survey g', r', and i' broadband filters, we monitored NGC 4395 for nine consecutive nights and obtained three light curves each with over 250 data points. The g' and r' bands include time variable contributions from H? and H?, respectively, plus continuum. The i' band is free of broad lines and covers exclusively continuum. We show that by looking for a peak in the difference between the cross-correlation and the auto-correlation functions for all combinations of filters, we can get a reliable estimate of the time lag necessary to compute M BH. We measure the time lag for H? to be 3.6 ± 0.8 hr, comparable to previous studies using the line-resolved spectroscopic RM method. We argue that this lag implies a black hole mass of M BH = (4.9 ± 2.6) × 104 M ?.

Edri, Haim; Rafter, Stephen E.; Chelouche, Doron; Kaspi, Shai; Behar, Ehud

2012-09-01

204

Binding of globular proteins to lipid membranes studied by isothermal titration calorimetry and fluorescence  

Microsoft Academic Search

The interactions of bovine serum albumin, lysozyme and cytochrome c with phosphatidylcholine liposomes in liquid crystalline phase have been investigated using isothermal titration calorimetry in combination with steady state, and fluorescence measurements. Calorimetric titration studies of the binding of liposomes to the protein species indicate in all cases exothermic processes with single binding sites in the protein molecule. Distinct saturation

Mariana N Dimitrova; Hideo Matsumura; Nelly Terezova; Vassil Neytchev

2002-01-01

205

Selective Two-Step Titration of Thorium by Sulfate Displacement of the Diethylenetriaminepentaacetic Acid Complex.  

National Technical Information Service (NTIS)

Thorium and other metals are complexed with excess diethylenetriaminepentaacetic acid (DTPA) at pH 1.4, the excess DTPA is titrated with Bi(III) to a xylenol orange end point, sulfate is added to complex Th(IV), and the displaced DTPA again is titrated wi...

P. Kiefer

1980-01-01

206

Quantification of the maleic anhydride grafted onto polypropylene by chemical and viscosimetric titrations, and FTIR spectroscopy  

Microsoft Academic Search

An acid–base titration method for an accurate and reproducible quantification of maleic anhydride grafted onto polyolefins is proposed. The use of an organic base (tetra-butylammonium hydroxide) enhances the base solubility in organic solvents and prevents phenomena like coarcervation. The titration goes on until the visual endpoint of a coloured indicator, corresponding to the neutralisation of the grafted functions. Bromothymol blue

M. Sclavons; P. Franquinet; V. Carlier; G. Verfaillie; I. Fallais; R. Legras; M. Laurent; F. C. Thyrion

2000-01-01

207

Simultaneous determination of mixtures of metal ions by complexometric titration and multivariate calibration  

Microsoft Academic Search

A new complexometric titration method for the determination of mixtures of metal ions with multivariate calibration was developed. The principle of this method is described and a linear complexometric titration equation is derived. In this work, a mercury film electrode (MFE) was used as indicator electrode for potentiometric measurements, and a double junction Ag\\/AgCl electrode as reference electrode. The mixtures

Yongnian Ni; Yingliang Wu

1997-01-01

208

A Laser-Pointer-Based Spectrometer for Endpoint Detection of EDTA Titrations  

ERIC Educational Resources Information Center

A laser spectrometer for the ethylenediaminetetra-acetic acid (EDTA) titration of magnesium or calcium ions that is designed around a handheld laser pointer as the source and a photoresistor as the detector is developed. Findings show that the use of the spectrometer reduces the degree of uncertainty and error in one part of the EDTA titrations,…

Dahm, Christopher E.; Hall, James W.; Mattioni, Brian E.

2004-01-01

209

Photometric astrometry applied to asteroids 6, 15, 43, and 624  

NASA Astrophysics Data System (ADS)

A new version of photometric astrometry is presented. This method made it possible to obtain the sense of rotation, sidereal period and pole orientation of the following asteroids: 6 Hebe, 15 Eunomia, 43 Ariadne and 624 Hektor.

Michalowski, Tadeusz

210

Photometric Properties of Phobos Surface Materials From Viking Images  

Microsoft Academic Search

Clear-filter Viking images, and an accurate numerical model of the shape of Phobos, have been used to determine this satellite's photometric properties. A global-average Hapke function derived from disk-resolved data confirms previous indications that Phobos has a strong opposition surge. Photometrically corrected images were mosaicked into an albedo map; most of the resulting normal reflectances are in the range 0.06–0.10,

Damon P. Simonelli; Michael Wisz; Andrew Switala; Daniel Adinolfi; Joseph Veverka; Peter C. Thomas; Paul Helfenstein

1998-01-01

211

Photometric study of the major satellites of Uranus  

Microsoft Academic Search

In this paper, we analyze the results of ground-based and space-born photometric observations of the major satellites of Uranus---Miranda, Ariel, Umbriel, Titania, and Oberon. All sets of photometric observations of the satellites available in the literature were examined for uniformity and systematic differences and summarized to a unified set by wavelength ranging from 0.25 to 2.4 mum. This set covers

V. V. Avramchuk; V. K. Rosenbush; T. P. Bul'Ba

2007-01-01

212

Photometric study of the major satellites of Uranus  

Microsoft Academic Search

In this paper, we analyze the results of ground-based and space-born photometric observations of the major satellites of Uranus—Miranda,\\u000a Ariel, Umbriel, Titania, and Oberon. All sets of photometric observations of the satellites available in the literature were\\u000a examined for uniformity and systematic differences and summarized to a unified set by wavelength ranging from 0.25 to 2.4\\u000a ?m. This set covers

V. V. Avramchuk; V. K. Rosenbush; T. P. Bul’ba

2007-01-01

213

Flame photometric detector for thin-layer chromatography  

Microsoft Academic Search

A new flame photometric detector for thin-layer chromatography (TLC) was studied to determine sulfur and phosphorus containing compounds in materials with a high boiling point. The detector was integrated with a flame ionization detector into the Iatroscan TLC–flame ionization detection analyzer. The principle of the detector is based on the photometric detection of flame emission of heteroatom in a hydrogen–air

Minoru Ogasawara; Kyoko Tsuruta; Shinsuke Arao

2002-01-01

214

Nonaqueous potentiometric titration and elemental analysis of high-boiling distillates of Saudi Arabian crude oils  

SciTech Connect

Nonaqueous potentiometric titration and elemental analysis were used to study basic and nonbasic functionalities present in high-boiling distillates of four Saudi Arabian crude oils. Model nitrogen compounds were titrated under similar titration conditions to differentiate them into strong, weak and nonbasic species. The strong bses titrated were due to the presence of of pyridine and its benzologs like acridines, phenanthridines and quionolines. The weak bases titrated were due to phenazxines and amides whereas the pyrroles, indoles and carbazoles were found to be nonbasic in nature. The total nitrogen and the total basic nitrogen compounds were generally found to be in very low concentration in the four crude oil distillates. A gradual decrease in the basicity of the distillates was found from Arab Heavy to Arab Extra Light through Arab Medium and Arab Light crude oils.

Ali, M.F.; Ali, M.A. (Dept. of Chemistry, King Fahd Univ. of Petroleum and Minerals, Dhahran 31261 (SA))

1988-12-01

215

Stepwise a.c. amperometric titration of cadmium and zinc with EGTA.  

PubMed

The theory of d.c. and a.c. amperometric titrations based on complexometric reactions is presented. It is shown that when E(1 2 )(M(I)) > E(1 2 )(M(II)) and log K(M(I)L) < log K(M(II)L), M(I) and M(II) can be sequentially determined by d.c. as well as a.c. amperometric titration. If, on the other hand E(1 2 )(M(I)) > E(1 2 )(M(II)) and log K(M(II)L), a stepwise titration can be performed only by a.c. amperometry. The effect of oxygen on an a.c. amperometric titration is also discussed. The stepwise a.c. amperometric titration of cadmium and zinc with EGTA at pH 6 in the presence of oxygen and an excess of 0.05 M acetate illustrates the theory. PMID:18961447

Asplund, J

1974-03-01

216

[Simultaneous determination of calcium and magnesium by calculative spectrophotometric complexometric titration].  

PubMed

A new spectrophotometric complexometric titration method coupled with chemometrics for the determination of mixtures of metal ions has been developed. In the method described here, the titrant is a mixture of EDTA and two indicators. In the process of titration, both the volumetric addition of titrant and the progress of titration reaction can be characterized simultaneously by chemometric calculation with the absorption spectra, and then the titration curves can be obtained. With the titration curves, a matrix equation can be established, and thus the concentration of each component in the mixture of metal ions can be calculated with principal component regression. The method only needs the information of absorption spectra to obtain the analytical results, and is free of volumetric measurements. So the method is simple, convenient and precise, and has been applied to the simultaneous determination of mixtures of calcium and magnesium using malachite green and Cu-PAN as indicators with satisfactory results. PMID:18330321

Liao, Li-fu; Xiao, Xi-lin; Yang, Ming-hui; Yang, Jing

2007-12-01

217

Hot biological catalysis: isothermal titration calorimetry to characterize enzymatic reactions.  

PubMed

Isothermal titration calorimetry (ITC) is a well-described technique that measures the heat released or absorbed during a chemical reaction, using it as an intrinsic probe to characterize virtually every chemical process. Nowadays, this technique is extensively applied to determine thermodynamic parameters of biomolecular binding equilibria. In addition, ITC has been demonstrated to be able of directly measuring kinetics and thermodynamic parameters (kcat, KM, ?H) of enzymatic reactions, even though this application is still underexploited. As heat changes spontaneously occur during enzymatic catalysis, ITC does not require any modification or labeling of the system under analysis and can be performed in solution. Moreover, the method needs little amount of material. These properties make ITC an invaluable, powerful and unique tool to study enzyme kinetics in several applications, such as, for example, drug discovery. In this work an experimental ITC-based method to quantify kinetics and thermodynamics of enzymatic reactions is thoroughly described. This method is applied to determine kcat and KM of the enzymatic hydrolysis of urea by Canavalia ensiformis (jack bean) urease. Calculation of intrinsic molar enthalpy (?Hint) of the reaction is performed. The values thus obtained are consistent with previous data reported in literature, demonstrating the reliability of the methodology. PMID:24747990

Mazzei, Luca; Ciurli, Stefano; Zambelli, Barbara

2014-01-01

218

Patient self-monitoring of blood pressure and self-titration of medication in primary care: the TASMINH2 trial qualitative study of health professionals' experiences  

PubMed Central

Background Self-monitoring with self-titration of antihypertensives leads to reduced blood pressure. Patients are keen on self-monitoring but little is known about healthcare professional views. Aim To explore health professionals‘ views and experiences of patient self-management, particularly with respect to future implementation into routine care. Design and setting Qualitative study embedded within a randomised controlled trial of healthcare professionals participating in the TASMINH2 trial of patient self-monitoring with self-titration of antihypertensives from 24 West Midlands general practices. Method Taped and transcribed semi-structured interviews with 13 GPs, two practice nurses and one healthcare assistant. Constant comparative method of analysis. Results Primary care professionals were positive about self-monitoring, but procedures for ensuring patients measured blood pressure correctly were haphazard. GPs interpreted home readings variably, with many not making adjustment for lower home blood pressure. Interviewees were satisfied with patient training and arrangements for blood pressure monitoring and self-titration of medication during the trial, but less sure about future implementation into routine care. There was evidence of a need for training of both patients and professionals for successful integration of self-management. Conclusion Health professionals wanted more patient involvement in hypertension care but needed a framework to work within. Consideration of how to train patients to measure blood pressure and how home readings become part of their care is required before self-monitoring and self-titration can be implemented widely. As home monitoring becomes more widespread, the development of patient self-management, including self-titration of medication, should follow but this may take time to achieve.

Jones, Miren I; Greenfield, Sheila M; Bray, Emma P; Hobbs, FD Richard; Holder, Roger; Little, Paul; Mant, Jonathan; Williams, Bryan; McManus, Richard J

2013-01-01

219

Photometric Metallicities in dSph Systems  

NASA Astrophysics Data System (ADS)

We present part of a project to test Strömgren, Washington, and Sloan filter systems for stellar population studies within SDSS-discovered dSph galaxies. We use the Boötes I dSph as a test case, finding that the Strömgren m1-index gives a more accurate metallicity estimate than the Washington filters for the individual upper-red giant branch stars, but only if 1% photometry is achieved. For individual stars, the resolution for the Strömgren filters in [Fe/H] is about 0.2-0.3 dex, but that very long exposures are necessary in the v-band to obtain useful data at the main-sequence turn-off. The faintness of the red giants in the bluer bands becomes problematic at Boötes I's distance of about 65 kpc. We conclude that Washington filters are better for systems with distances >50 kpc or so, except where there is considerable reddening present (although CT1T2 would still be better than ugriz by a factor of two). For future surveys using the Sloan filters, we recommend adding the Washington C-filter to the Sloan set: the (C-r)-color is the best (and cheapest) metallicity-sensitive compromise for stellar population studies. Using the m1-index and the (C-T1) color, we can detect a metallicity spread of -1.1 < [Fe/H] < -2.7, and we have been able to determine photometric metallicities on the lower red giant branch, which is not possible with the Strömgren system alone.

Hughes, J.; Wallerstein, G.

2011-12-01

220

Photometric reverberation mapping of 3C 120  

NASA Astrophysics Data System (ADS)

We present the results of a five month monitoring campaign of the local active galactic nuclei (AGN) 3C 120. Observations with a median sampling of two days were conducted with the robotic 15 cm telescope VYSOS-6 located near Cerro Armazones in Chile. Broad band (B, V) and narrow band (NB) filters were used in order to measure fluxes of the AGN and the H? broad line region (BLR) emission line. The NB flux is constituted by about 50% continuum and 50% H? emission line. To disentangle line and continuum flux, a synthetic H? light curve was created by subtracting a scaled V-band light curve from the NB light curve. Here we show that the H? emission line responds to continuum variations with a rest frame lag of 23.6 ± 1.69 days. We estimate a virial mass of the central black hole MBH = 57 ± 27 × 106 M?, by combining the obtained lag with the velocity dispersion of a single contemporaneous spectrum. Using the flux variation gradient method, we determined the host galaxy subtracted rest frame 5100 Å luminosity at the time of our monitoring campaign with an uncertainty of 10% (LAGN = (6.94 ± 0.71) × 1043 erg s-1). Compared with recent spectroscopic reverberation results, 3C 120 shifts in the RBLR - LAGN diagram remarkably close to the theoretically expected relation of R ? L0.5. Our results demonstrate the performance of photometric AGN reverberation mapping, in particular for efficiently determining the BLR size and the AGN luminosity. Table 5 is available in electronic form at http://www.aanda.org

Pozo Nuñez, F.; Ramolla, M.; Westhues, C.; Bruckmann, C.; Haas, M.; Chini, R.; Steenbrugge, K.; Murphy, M.

2012-09-01

221

LESS photometric redshift survey (Wardlow+, 2011)  

NASA Astrophysics Data System (ADS)

SMGs typically have faint optical and near-IR counterparts (e.g. Ivison et al. 2002MNRAS.337....1I), so we require deep photometry for accurate photometric redshift estimates. The ECDF-S was chosen for this survey because it is an exceptionally well-studied field and as such we are able to utilize data from extensive archival imaging and spectroscopic surveys. For completeness and uniformity, we only consider surveys that cover a large fraction of the ECDF-S rather than the smaller and deeper central Chandra Deep Field-South (CDF-S) region. Therefore, we utilize the MUltiwavelength Survey by Yale-Chile (MUSYC; Gawiser et al. 2006, Cat. J/ApJS/162/1) near-IR survey for U- to K-band imaging (Taylor et al. 2009, Cat. J/ApJS/183/295), and the Spitzer IRAC/MUSYC Public Legacy in ECDF-S (SIMPLE) imaging for Spitzer IRAC data (Damen et al. 2011, cat. J/ApJ/727/1). We also include U-band data from the deep GOODS/VIMOS imaging survey of the CDF-S (Nonino et al. 2009ApJS..183..244N); although this covers only ~60 per cent of LESS SMGs, it is valuable for galaxies that are undetected at short wavelengths in the shallower MUSYC survey. In addition, we have carried out deep near-IR observations in the J and Ks bands with the HAWK-I at the ESO-VLT (ID: 082.A-0890, PI: N. Padilla). (2 data files).

Wardlow, J. L.; Smail, I.; Coppin, K. E. K.; Alexander, D. M.; Brandt, W. N.; Danielson, A. L. R.; Luo, B.; Swinbank, A. M.; Walter, F.; Weiss, A.; Xue, Y. Q.; Zibetti, S.; Bertoldi, F.; Biggs, A. D.; Chapman, S. C.; Dannerbauer, H.; Dunlop, J. S.; Gawiser, E.; Ivison, R. J.; Knudsen, K. K.; Kovacs, A.; Lacey, C. G.; Menten, K. M.; Padilla, N.; Rix, H.-W.; van der Werf, P. P.

2012-02-01

222

Photometric redshifts from evolutionary synthesis with PÉGASE: The code Z-PEG and the z=0 age constraint  

NASA Astrophysics Data System (ADS)

Photometric redshifts are estimated on the basis of template scenarios with the help of the code Z-PEG, an extension of the galaxy evolution model PÉGASE.2 and available on the PÉGASE web site. The spectral energy distribution (SED) templates are computed for nine spectral types including starburst, irregular, spiral and elliptical. Dust, extinction and metal effects are coherently taken into account, depending on evolution scenarios. The sensitivity of results to adding near-infrared colors and IGM absorption is analyzed. A comparison with results of other models without evolution measures the evolution factor which systematically increases the estimated photometric redshift values by Delta z >= 0.2 for z > 1.5. Moreover we systematically check that the evolution scenarios match observational standard templates of nearby galaxies, implying an age constraint of the stellar population at z=0 for each type. The respect of this constraint makes it possible to significantly improve the accuracy of photometric redshifts by decreasing the well-known degeneracy problem. The method is applied to the HDF-N sample (see in Fernández-Soto et al. 1999). From fits on SED templates by a chi 2-minimization procedure, not only is the photometric redshift derived but also the corresponding spectral type and the formation redshift zfor when stars first formed. Early epochs of galaxy formation zfor > 5 are found from this new method and results are compared to faint galaxy count interpretations. The new tool is available at: http://www.iap.fr/pegase

Le Borgne, D.; Rocca-Volmerange, B.

2002-05-01

223

[Determination of total protein content in soya-bean milk via visual moving reaction boundary titration].  

PubMed

A visual, rapid and accurate moving reaction boundary titration (MRBT) method was used for the determination of the total protein in soya-bean milk. During the process, moving reaction boundary (MRB) was formed by hydroxyl ions in the catholyte and soya-bean milk proteins immobilized in polyacrylamide gel (PAG), and an acid-base indicator was used to denote the boundary motion. The velocity of MRB has a relationship with protein concentration, which was used to obtain a standard curve. By paired t-test, there was no significant difference of the protein content between MRBT and Kjeldahl method at 95% confidence interval. The procedure of MRBT method required about 10 min, and it had linearity in the range of 2.0-14.0 g/L, low limit of detection (0.05 g/L), good precision (RSD of intra-day < 1.90% and inter-day < 4.39%), and high recoveries (97.41%-99.91%). In addition, non-protein nitrogen (NPN) such as melamine added into the soya-bean milk had weak influence on MRBT results. PMID:24558841

Guo, Chengye; Wang, Houyu; Zhang, Lei; Fan, Liuyin; Cao, Chengxi

2013-11-01

224

Photometric Determination of pH with a Single Standard and Calculation by Nomogram Applicationto HumanPlasma pH  

Microsoft Academic Search

A method is described for construction of a nomogram, based on the Henderson- Hasselbalch equation, with which photometric pH values can be calculated from the absorbance of an indicator in a sample and the absorbance of the indicator in a single standard solution. Thereby the necessity of preparing calibration curves from a series of standard solutions is avoided. The procedure

Lawrence V. Hankes; Janis John Vitols

225

Iron Analysis by Redox Titration. A General Chemistry Experiment.  

ERIC Educational Resources Information Center

Describes a simplified redox method for total iron analysis suitable for execution in a three-hour laboratory period by general chemistry students. Discusses materials, procedures, analyses, and student performance. (CW)

Kaufman, Samuel; DeVoe, Howard

1988-01-01

226

Some Tungsten Oxidation-Reduction Chemistry: A Paint Pot Titration.  

ERIC Educational Resources Information Center

Reports an oxidation-reduction experiment using tungsten, somewhat analogous to the classical student experiment involving oxidation-reduction of vanadium. Includes experimental procedures, results, and toxicity/cost of tungsten compounds. (Author/JN)

Pickering, Miles; Monts, David L.

1982-01-01

227

Thermometric titration in investigation of the formation of polyanions of molybdenum(VI), tungsten(VI), vanadium(V), and chromium(VI). III. Titration of molybdic acid with sodium hydroxide solution  

Microsoft Academic Search

To define the propenties of molybdenum-containing species which appear ; in the acidification of neutral molybdate solution with mineral acid, the reverse ; process (i.e., the titration of molybdic acid of acidified molybdate solution ; with sodium hydroxide) was examined and the titration curves were obtained ; thermometrically as well as potentiometrically. In the thermometric titration ; curves there are

Nobutoshi Kiba; Tsugio Takeuchi

1973-01-01

228

Experimental parameters in the photometric analysis of uranium in TBP-dodecane solutions  

SciTech Connect

A systematic study of the direct colorimetric determination of uranium in tributyl phosphate-dodecane solutions has been made. A number of parameters, including HNO{sub 3}, TBP, mono- and dibutyl phosphate concentrations, temperature, and extent of solvent degradation, have been investigated to determine what effect they have on the accuracy of uranium analysis. The procedure, based on the absorbance of UO{sub 2}(NO{sub 3}){sub 2}.2TBP at 416 nm, was found to be independent of HNO{sub 3} concentration and is not significantly affected by fluctuations in the concentration of TBP, MBP, and DBP under normal operating conditions. Phase separation occurs in hydrated organic samples at elevated temperatures; however, the accuracy of the photometric method is essentially independent of temperature fluctuations if the absorbance at 550 nm is used to correct 416-nm absorbance for sample opacity. Significant positive bias in assay results is observed in organic streams when spent TBP is recycled through the reprocessing facility. The absorbance from solvent coloration, produced by the presence of TBP nitrification products, must be subtracted from the total 416-nm absorbance to obtain an accurate analysis of uranium under these process conditions. The operating range of the procedure, using a 0.5-cm photometric cell, is 1 to 100 g/l U, with an estimated accuracy of +-0.5 g/l U.

Bostick, D.T.; Strain, J.E.

1981-01-01

229

Optical Photometric Observations of GEO Debris  

NASA Technical Reports Server (NTRS)

We report on a continuing program of optical photometric measurements of faint orbital debris at geosynchronous Earth orbit (GEO). These observations can be compared with laboratory studies of actual spacecraft materials in an effort to determine what the faint debris at GEO may be. We have optical observations from Cerro Tololo Inter-American Observatory (CTIO) in Chile of two samples of debris: 1. GEO objects discovered in a survey with the University of Michigan's 0.6-m aperture Curtis-Schmidt telescope MODEST (for Michigan Orbital DEbris Survey Telescope), and then followed up in real-time with the CTIO/SMARTS 0.9-m for orbits and photometry. Our goal is to determine 6 parameter orbits and measure colors for all objects fainter than R = 15 t11 magnitude that are discovered in the MODEST survey. 2. A smaller sample of high area to mass ratio (AMR) objects discovered independently, and acquired using predictions from orbits derived from independent tracking data collected days prior to the observations. Our optical observations in standard astronomical BVRI filters are done with either telescope, and with the telescope tracking the debris object at the object's angular rate. Observations in different filters are obtained sequentially. We have obtained 71 calibrated sequences of R-B-V-I-R magnitudes. A total of 66 of these sequences have 3 or more good measurements in all filters (not contaminated by star streaks or in Earth's shadow). Most of these sequences show brightness variations, but a small subset has observed brightness variations consistent with that expected from observational errors alone. The majority of these stable objects are redder than a solar color in both B-R and R-I. There is no dependence on color with brightness. For a smaller sample of objects we have observed with synchronized CCD cameras on the two telescopes. The CTIO 0.9-m observes in B, and MODEST in R. The CCD cameras are electronically linked together so that the start time and duration of observations are the same to better than 50 milliseconds. Thus, the B-R color is a true measure of the surface of the debris piece facing the telescopes for that observation. Any change in color reflects a real change in the debris surface. We will compare our observations with models and laboratory measurements of selected surfaces.

Seitzer, Patrick; Rodriquez-Cowardin, Heather M.; Barker, Edwin S.; Abercromby, Kira J.; Kelecy, Thomas M.; Horstman, Matt

2010-01-01

230

Photometric calibrations for 21st century science  

SciTech Connect

The answers to fundamental science questions in astrophysics, ranging from the history of the expansion of the universe to the sizes of nearby stars, hinge on our ability to make precise measurements of diverse astronomical objects. As our knowledge of the underlying physics of objects improves along with advances in detectors and instrumentation, the limits on our capability to extract science from measurements is set, not by our lack of understanding of the nature of these objects, but rather by the most mundane of all issues: the precision with which we can calibrate observations in physical units. In principle, photometric calibration is a solved problem - laboratory reference standards such as blackbody furnaces achieve precisions well in excess of those needed for astrophysics. In practice, however, transferring the calibration from these laboratory standards to astronomical objects of interest is far from trivial - the transfer must reach outside the atmosphere, extend over 4{pi} steradians of sky, cover a wide range of wavelengths, and span an enormous dynamic range in intensity. Virtually all spectrophotometric observations today are calibrated against one or more stellar reference sources, such as Vega, which are themselves tied back to laboratory standards in a variety of ways. This system's accuracy is not uniform. Selected regions of the electromagnetic spectrum are calibrated extremely well, but discontinuities of a few percent still exist, e.g., between the optical and infrared. Independently, model stellar atmospheres are used to calibrate the spectra of selected white dwarf stars, e.g. the HST system, but the ultimate accuracy of this system should be verified against laboratory sources. Our traditional standard star systems, while sufficient until now, need to be improved and extended in order to serve future astrophysics experiments. This white paper calls for a program to improve upon and expand the current networks of spectrophotometrically calibrated stars to provide precise calibration with an accuracy of equal to and better than 1% in the ultraviolet, visible and near-infrared portions of the spectrum, with excellent sky coverage and large dynamic range.

Kent, Stephen; /Fermilab; Kaiser, Mary Elizabeth; /Johns Hopkins U.; Deustua, Susana E.; /Baltimore, Space Telescope Sci.; Smith, J.Allyn; /Austin Peay State U.; Adelman, Saul; /Citadel Military Coll.; Allam, Sahar S.; /Fermilab; Baptista, Brian; /Indiana U.; Bohlin, Ralph C.; /Baltimore, Space Telescope Sci.; Clem, James L.; /Louisiana State U.; Conley, Alex; /Colorado U.; Edelstein, Jerry; /UC, Berkeley, Space Sci. Dept. /NOAO, Tucson

2009-02-01

231

Photometric Studies of Orbital Debris at GEO  

NASA Technical Reports Server (NTRS)

Orbital debris represents a significant and increasing risk to operational spacecraft. Here we report on photometric observations made in standard BVRI filters at the Cerro Tololo Inter-American Observatory (CTIO) in an effort to determine the physical characteristics of optically faint debris at geosynchronous Earth orbit (GEO). Our sample is taken from GEO objects discovered in a survey with the University of Michigan s 0.6-m Curtis-Schmidt telescope (known as MODEST, for Michigan Orbital DEbris Survey Telescope), and then followed up in real-time with the CTIO/SMARTS 0.9-m for orbits and photometry. For a sample of 50 objects, calibrated sequences in RB- V-I-R filters have been obtained with the CTIO/SMARTS 0.9-m. For objects that do not show large brightness variations, the colors are largely redder than solar in both B-R and R-I. The width of the color distribution may be intrinsic to the nature of the surfaces, but also could imply that we are seeing irregularly shaped objects and measuring the colors at different times with just one telescope. For irregularly shaped objects tumbling at unknown orientations and rates, such sequential filter measurements using one telescope are subject to large errors for interpretation. If all observations in all filters in a particular sequence are of the same surface at the same solar and viewing angles, then the colors are meaningful. Where this is not the case, interpretation of the observed colors is impossible. For a smaller sample of objects we have observed with synchronized CCD cameras on the two telescopes. The CTIO/SMARTS 0.9-m observes in B, and the Schmidt in R. The CCD cameras are electronically linked together so that the start time and duration of observations are both the same to better than 50 milliseconds. Now the observed B-R color is a true measure of the scattered illuminated area of the debris piece for that observation.

Seitzer, Patrick; Cowardin, Heather M.; Barker, Ed; Abercromby, Kira J.; Foreman, Gary; Hortsman, Matt

2009-01-01

232

Simple home-made sensors for potentiometric titrations. [Nitroform CH(NO/sub 2/)/sub 3/  

SciTech Connect

A sensor for potentiometric titrations was prepared by coating a spectroscopic graphite rod with a solution of poly(vinyl chloride) and dioctyphthalate in tetrahydrofuran. The reference electrode was an Ag/AgCl single-junction electrode. The sensor was used in precipitation, acid-base, compleximetric, and redox titrations. Preparation of the coated-graphite sensor is simple and rapid. Moreover, it is quite inexpensive. A limitation is its applicability in aqueous media only, because organic solvents will dissolve the membrane. Various uncoated types of graphite have also been investigated as sensors, particularly in two applications of interest in the analysis of propellants: the titration of nitroform and perchlorate. Obviously, these sensors can be used also in nonaqueous, or partially nonaqueous media. These sensors may also find use in the potentiometric titration of fluoride vs La(III) or Th(IV).

Selig, W.

1982-04-01

233

A Computer-Based Simulation of an Acid-Base Titration  

ERIC Educational Resources Information Center

Reviews the advantages of computer simulated environments for experiments, referring in particular to acid-base titrations. Includes pre-lab instructions and a sample computer printout of a student's use of an acid-base simulation. Ten references. (PR)

Boblick, John M.

1971-01-01

234

Effect of Molecular Acid-Base Dissociation of Salts on Conductometric Titration Curves in Acetonitrile.  

National Technical Information Service (NTIS)

The main objectives of the paper are to calculate Kf and Kd from the characteristics of conductometric titration curves at different initial concentrations of acid. Equations were derived to find, under specified conditions, Kf from the location of and Kd...

I. M. Kolthoff M. K. Chantooni

1964-01-01

235

Physical characterization of asteroid surfaces from photometric analysis  

NASA Technical Reports Server (NTRS)

The feasibility of using photometric models like Hapke's (1981, 1984, 1986) equation for deriving physical properties of asteroids from photometric observations is discussed. Using data for Ceres and Vesta, it is shown that the incomplete phase-angle coverage limits the reliable determination of Hapke's photometric parameters from asteroid disk-integrated phase curves (the second limitation is the nonsphericity of many asteroids). However, within this limitations, certain trends among asteroids can be compared. It is shown that there is a general similarity among the Hapke's parameters other than the h parameter, which characterizes the width of the opposition surge in terms of soil structure (porosity, particle-size distribution, and the rate of compaction with depth), derived for similar objects, e.g., average C asteroids and Ceres, and average S asteroids, 1982 Apollo, and Vesta.

Helfenstein, P.; Veverka, J.

1989-01-01

236

Photometric Analysis in the Kepler Science Operations Center Pipeline  

NASA Technical Reports Server (NTRS)

We describe the Photometric Analysis (PA) software component and its context in the Kepler Science Operations Center (SOC) pipeline. The primary tasks of this module are to compute the photometric flux and photocenters (centroids) for over 160,000 long cadence (thirty minute) and 512 short cadence (one minute) stellar targets from the calibrated pixels in their respective apertures. We discuss the science algorithms for long and short cadence PA: cosmic ray cleaning; background estimation and removal; aperture photometry; and flux-weighted centroiding. We discuss the end-to-end propagation of uncertainties for the science algorithms. Finally, we present examples of photometric apertures, raw flux light curves, and centroid time series from Kepler flight data. PA light curves, centroid time series, and barycentric timestamp corrections are exported to the Multi-mission Archive at Space Telescope [Science Institute] (MAST) and are made available to the general public in accordance with the NASA/Kepler data release policy.

Twicken, Joseph D.; Clarke, Bruce D.; Bryson, Stephen T.; Tenenbaum, Peter; Wu, Hayley; Jenkins, Jon M.; Girouard, Forrest; Klaus, Todd C.

2010-01-01

237

Photometric analysis in the Kepler Science Operations Center pipeline  

NASA Astrophysics Data System (ADS)

We describe the Photometric Analysis (PA) software component and its context in the Kepler Science Operations Center (SOC) Science Processing Pipeline. The primary tasks of this module are to compute the photometric flux and photocenters (centroids) for over 160,000 long cadence (~thirty minute) and 512 short cadence (~one minute) stellar targets from the calibrated pixels in their respective apertures. We discuss science algorithms for long and short cadence PA: cosmic ray cleaning; background estimation and removal; aperture photometry; and flux-weighted centroiding. We discuss the end-to-end propagation of uncertainties for the science algorithms. Finally, we present examples of photometric apertures, raw flux light curves, and centroid time series from Kepler flight data. PA light curves, centroid time series, and barycentric timestamp corrections are exported to the Multi-mission Archive at Space Telescope [Science Institute] (MAST) and are made available to the general public in accordance with the NASA/Kepler data release policy.

Twicken, Joseph D.; Clarke, Bruce D.; Bryson, Stephen T.; Tenenbaum, Peter; Wu, Hayley; Jenkins, Jon M.; Girouard, Forrest; Klaus, Todd C.

2010-07-01

238

First photometric study of W UMa binary star LU Lac  

NASA Astrophysics Data System (ADS)

LU Lac is a neglected W UMa binary star in photometric investigations. In this paper, we present BVRI CCD photometric light curves obtained on one night in 2012. The first photometric solutions of this system are computed by using the Wilson-Devinney code. It is shown that LU Lac is a marginal contact W-type system with a degree of contact factor of f=8.9%, a mass ratio of q=2.085 and a high inclination of i=82°.20. From the first analyses of orbital period changes, we found the period variation of the system includes an oscillation (A3=0.0125 days and T3=51.92 years). The cyclic change may be attributed to the light-travel time effect through the presence of a third body.

Liao, W.-P.; Qian, S.-B.; Zhao, E.-G.; Jiang, L.-Q.

2014-08-01

239

Towards a photometric metallicity scale for open clusters  

NASA Astrophysics Data System (ADS)

Context. Open clusters are a useful tool when investigating several topics connected with stellar evolution; for example the age or distance can be more accurately determined than for field stars. However, one important parameter, the metallicity, is only known for a marginal percentage of open clusters. Aims: We aim at a consistent set of parameters for the open clusters investigated in our photometric ?a survey of chemically peculiar stars. Special attention is paid to expanding our knowledge of cluster metallicities and verifying their scale. Methods: Making use of a previously developed method based on normalised evolutionary grids and photometric data, the distance, age, reddening, and metallicity of open clusters were derived. To transform photometric measurements into effective temperatures to use as input for our method, a set of temperature calibrations for the most commonly used colour indices and photometric systems was compiled. Results: We analysed 58 open clusters in total. Our derived metallicity values were in excellent agreement with about 30 spectroscopically studied targets. The mean value of the absolute deviations was found to be 0.03 dex, with no noticeable offset or gradient. The method was also applied using recent evolutionary models based on the currently accepted lower solar abundance value Z ~ 0.014. No significant differences were found compared to grids using the former adopted solar value Z = 0.02. Furthermore, some divergent photometric datasets were identified and discussed. Conclusions: The method provides an accurate way of obtaining properly scaled metallicity values for open clusters. In light of present and future homogeneous photometric sky surveys, the sample of stellar clusters can be extended to the outskirts of the Milky Way, where spectroscopic studies are almost impossible. This will help for determining galactic metallicity gradients in more detail. Figure 7 is available in electronic form at http://www.aanda.org

Netopil, M.; Paunzen, E.

2013-09-01

240

Helix-coil transformation and titration curve of poly-L-glutamic acid  

Microsoft Academic Search

The titration curve of poly-L-glutamic acid was studied in connection with the helix-coil transformation. In aqueous solution the transformation has its origin in the ionization of the polar group COOH in the side chain. Conversely the ionization and the titration curve of this molecule are affected by the change of the electrostatic interaction produced by its transformation. It is shown

Akiyoshi Wada

1960-01-01

241

An automated precise Winkler titration for determining dissolved oxygen on board ship  

Microsoft Academic Search

An automated titration for the Winkler method is presented for measuring primary productivity in the ocean. The system is based on a microcomputer-controlled titration with potentiometric endpoint detection. By the use of 0.005-N sodium thiosulfate as a titrant and a program designed to shorten the time for measuring, the method achieves a precision of 0.04% coefficient of variation with a

Ken Furuya; Kazutoshi Harada

1995-01-01

242

Pulsating potentiometric titration technique for assay of dissolved oxygen in water at trace level  

Microsoft Academic Search

A simple but high performance potentiometric titration technique using pulsating sensors has been developed for assay of dissolved oxygen (DO) in water samples down to 10.0?gL?1 levels. The technique involves Winkler titration chemistry, commonly used for determination of dissolved oxygen in water at mgL?1 levels, with modification in methodology for accurate detection of end point even at 10.0?gL?1 levels DO

P. Sahoo; R. Ananthanarayanan; N. Malathi; M. P. Rajiniganth; N. Murali; P. Swaminathan

2010-01-01

243

Thermodynamics of Cationic Lipid-DNA Complex Formation as Studied by Isothermal Titration Calorimetry  

Microsoft Academic Search

The detailed analysis of the cationic lipid-DNA complex formation by means of isothermal titration calorimetry is presented. Most experiments were done using 1,2-dioleyl-sn-glycero-3-ethylphosphocholine (EDOPC), but basic titrations were also done using DOTAP, DOTAP:DOPC, and DOTAP:DOPE mixtures. Complex formation was endothermic with less than 1kcal absorbed per mole of lipid or DNA charge. This enthalpy change was attributed to DNA-DNA mutual

Edwin Pozharski; Robert C. MacDonald

2002-01-01

244

Report of a patient chewing fentanyl patches who was titrated onto methadone  

PubMed Central

This case report discusses the clinical presentation and management of a patient presenting to substance misuse services reporting chewing fentanyl patches in addition to wearing them transdermally. The patient was successfully titrated onto methadone 30 mg. Only one previously reported case of an individual chewing fentanyl patches was found in the literature; no case reports were found where treatment involved titrating the patient onto methadone. The pharmacology and illicit use of fentanyl are also considered.

Dale, Eric; Ashby, Fleur; Seelam, Kalyan

2009-01-01

245

The Softening of Hard Water and Complexometric Titrations. An Undergraduate Experiment  

Microsoft Academic Search

A 2-hour experiment for undergraduates is presented in which (i) water hardness is explained and demonstrated; (ii) ion-exchange resin properties are visually demonstrated and then used for softening water; (iii) complexometric titrations are used for evaluating water hardness before and after softening; and (iv) acid-base titration can be used to show that the Ca\\/Mg ions removed by the ion exchanger

Helena Ceretti; Enrique A. Hughes; Anita Zalts

1999-01-01

246

Complexometric titration of copper (II) using chromotropic acid dioxime as a metal indicator  

Microsoft Academic Search

Chromotropic acid dioxime forms purple coloured complexes with copper in the pH ranges 5.82 to 6.45 and 7.25 to 8.05 respectively which are less stable than the CuII-EDTA complex. On titrating these solutions with EDTA, the purple coloured complexes turn colourless or yellow at the end point. These titrations give satisfactory results in the temperature ranges 20 to 70° C

A. B. Sen; T. S. Srivastava

1963-01-01

247

Photometric redshifts determinations for galaxies by means of multicolor photometry  

NASA Astrophysics Data System (ADS)

Multicolor photometry is increasingly used for galaxies redshifts estimations. Using optical and NIR photometrical data and HST/WFPC2 morphological data we analyze the environments of radio galaxies 3C 184 (z = 0.996, 35 galaxies in a 6.2 arcmin2 field) and 3C 210 (z = 1.169, 57 galaxies in a 6.2 arcmin2 field). Color - color diagrams, red sequence technique and template fitting technique are used in order to determine the photometric redshifts of galaxies and to analyze the clustering of galaxies and ERGs (extremely red galaxies) in the environment of these two radio galaxies at z ~ 1.

Popescu, Nedelia A.

2007-03-01

248

Simulation and analysis of ACB'S photometric signature based on STK  

NASA Astrophysics Data System (ADS)

The basic theory of observations on ACBs' photometric signature is studied in this paper. A ground-based opto-electrionic observation emulation method with STK and MATLAB is presented to solve the problem that the real space observation is hardly run under the condition of technology institute. A spatial object brightness change model is established in combination of blackbody radiation theory. The photometric characteristics of space object are then analyzed using the above model by the simulation platform. Respectively, a low-orbit satellite and a tumbling rocket are simulated. The desired results are achieved by analysing brightness changes of the targets on various operating.

Zhang, Liangliang; Ma, Debao; Niu, Chaoyang

2010-05-01

249

New approach in the treatment of data from an acid-base potentiometric titrationI. Monocomponent systems of monofunctional acids and bases.  

PubMed

Based on precise analysis of the acid-base equilibrium, a new approach in the treatment of experimental data from a potentiometric titration is proposed. A new general formula giving explicitly the relation V=f([H(+)]) is derived, valid for every acid-base titration, which includes mono- and polyfunctional protolytes and their mixtures. The present study is the first practical application of this formula for the simplest case, the analysis of one monofunctional protolyte. The collected mV data during the titration are converted into pH-values by means of an auto pH-calibration procedure, thus avoiding preliminary preparation of the measuring system. The mentioned pH-calibration method is applicable also in water-organic mixtures and allows the quantitative determination of sparingly soluble substances (particularly pharmaceuticals). The treatment of the data is performed by means of ready-to-use software products, which makes the proposed approach accessible for a wide range of applications. PMID:12560965

Maslarska, Vania; Tencheva, Jasmina; Budevsky, Omortag

2003-01-01

250

SHARDS: An Optical Spectro-photometric Survey of Distant Galaxies  

NASA Astrophysics Data System (ADS)

We present the Survey for High-z Absorption Red and Dead Sources (SHARDS), an ESO/GTC Large Program carried out using the OSIRIS instrument on the 10.4 m Gran Telescopio Canarias (GTC). SHARDS is an ultra-deep optical spectro-photometric survey of the GOODS-N field covering 130 arcmin2 at wavelengths between 500 and 950 nm with 24 contiguous medium-band filters (providing a spectral resolution R ~ 50). The data reach an AB magnitude of 26.5 (at least at a 3? level) with sub-arcsec seeing in all bands. SHARDS' main goal is to obtain accurate physical properties of intermediate- and high-z galaxies using well-sampled optical spectral energy distributions (SEDs) with sufficient spectral resolution to measure absorption and emission features, whose analysis will provide reliable stellar population and active galactic nucleus (AGN) parameters. Among the different populations of high-z galaxies, SHARDS' principal targets are massive quiescent galaxies at z > 1, whose existence is one of the major challenges facing current hierarchical models of galaxy formation. In this paper, we outline the observational strategy and include a detailed discussion of the special reduction and calibration procedures which should be applied to the GTC/OSIRIS data. An assessment of the SHARDS data quality is also performed. We present science demonstration results on the detection and study of emission-line galaxies (star-forming objects and AGNs) at z = 0-5. We also analyze the SEDs for a sample of 27 quiescent massive galaxies with spectroscopic redshifts in the range 1.0 < z <~ 1.4. We discuss the improvements introduced by the SHARDS data set in the analysis of their star formation history and stellar properties. We discuss the systematics arising from the use of different stellar population libraries, typical in this kind of study. Averaging the results from the different libraries, we find that the UV-to-MIR SEDs of the massive quiescent galaxies at z = 1.0-1.4 are well described by an exponentially decaying star formation history with scale ? = 100-200 Myr, age around 1.5-2.0 Gyr, solar or slightly sub-solar metallicity, and moderate extinction, A(V) ~ 0.5 mag. We also find that galaxies with masses above M* are typically older than lighter galaxies, as expected in a downsizing scenario of galaxy formation. This trend is, however, model dependent, i.e., it is significantly more evident in the results obtained with some stellar population synthesis libraries, and almost absent in others.

Pérez-González, Pablo G.; Cava, Antonio; Barro, Guillermo; Villar, Víctor; Cardiel, Nicolás; Ferreras, Ignacio; Rodríguez-Espinosa, José Miguel; Alonso-Herrero, Almudena; Balcells, Marc; Cenarro, Javier; Cepa, Jordi; Charlot, Stéphane; Cimatti, Andrea; Conselice, Christopher J.; Daddi, Emmanuele; Donley, Jennifer; Elbaz, David; Espino, Néstor; Gallego, Jesús; Gobat, R.; González-Martín, Omaira; Guzmán, Rafael; Hernán-Caballero, Antonio; Muñoz-Tuñón, Casiana; Renzini, Alvio; Rodríguez-Zaurín, Javier; Tresse, Laurence; Trujillo, Ignacio; Zamorano, Jaime

2013-01-01

251

Rapid Titration of Measles and Other Viruses: Optimization with Determination of Replication Cycle Length  

PubMed Central

Background Measles virus (MV) is a member of the Paramyxoviridae family and an important human pathogen causing strong immunosuppression in affected individuals and a considerable number of deaths worldwide. Currently, measles is a re-emerging disease in developed countries. MV is usually quantified in infectious units as determined by limiting dilution and counting of plaque forming unit either directly (PFU method) or indirectly from random distribution in microwells (TCID50 method). Both methods are time-consuming (up to several days), cumbersome and, in the case of the PFU assay, possibly operator dependent. Methods/Findings A rapid, optimized, accurate, and reliable technique for titration of measles virus was developed based on the detection of virus infected cells by flow cytometry, single round of infection and titer calculation according to the Poisson's law. The kinetics follow up of the number of infected cells after infection with serial dilutions of a virus allowed estimation of the duration of the replication cycle, and consequently, the optimal infection time. The assay was set up to quantify measles virus, vesicular stomatitis virus (VSV), and human immunodeficiency virus type 1 (HIV-1) using antibody labeling of viral glycoprotein, virus encoded fluorescent reporter protein and an inducible fluorescent-reporter cell line, respectively. Conclusion Overall, performing the assay takes only 24–30 hours for MV strains, 12 hours for VSV, and 52 hours for HIV-1. The step-by-step procedure we have set up can be, in principle, applicable to accurately quantify any virus including lentiviral vectors, provided that a virus encoded gene product can be detected by flow cytometry.

Grigorov, Boyan; Rabilloud, Jessica; Lawrence, Philip; Gerlier, Denis

2011-01-01

252

A Photometric Observing Program at the VATT: Setting Up a Calibration Field  

NASA Astrophysics Data System (ADS)

Philip and Boyle have been making Strömgren and then Strömvil photometric observations of open and globular clusters at the Vatican Advanced Technology Telescope located on Mt. Graham in Arizona. Our aim is to obtain CCD photometric indices good to 0.01 magnitude. Indices of this quality can later be analyzed to yield estimates of temperature, luminosity and metallicity. But we have found that the CCD chip does not yield photometry of this quality without further corrections. Our most observed cluster is the open cluster, M 67. This cluster is also very well observed in the literature. We took the best published values and created a set of "standard" stars for our field. Taking our CCD results we could calculate deltas, as a function of position on the chip, which we then applied to all the CCD frames that we obtained. With this procedure we were able to obtain the precision of 0.01 magnitudes in all the fields that we observed. When we started we were able to use the "A" two-inch square Strömgren four-color set from KPNO. Later the Vatican Observatory bought a set of 3.48 inch square Strömgren filters, The Vatican Observatory had a set of circular Vilnius filters There was also an X filter. These eight filters made our Strömvil set.

Davis Philip, A. G.; Boyle, R. P.; Janusz, R.

2009-05-01

253

Archive of Photometric Plates Obtained at Cluj Astronomical Observatory  

NASA Astrophysics Data System (ADS)

The archive of photometric plates obtained at the Astronomical Observatory of Cluj in the period 1952-1974 is presented. The plate inventory is made within the framework of the Wide-Field Plate Database project. The plates were taken in the regions around 110 variable stars (eclipsing variables and RR Lyrae-type stars), as well as in some comparison stars regions.

Blaga, Cristina; Chi?, Gheorge-Dorin; Mircea, Liviu

254

Stars with large HIP photometric amplitudes (Adelman, 2001)  

NASA Astrophysics Data System (ADS)

A list of the 2027 stars that have the largest photometric amplitudes in Hipparcos Photometry shows that the most variables stars are all Miras. The percentage of variable types change as a function of amplitude. This compilation should also be of value to photometrists looking for relatively unstudied, but large amplitude stars. (1 data file).

Adelman, S. J.

2002-07-01

255

Infrared Imaging, Spectroscopic, and Photometric Studies of Comets.  

National Technical Information Service (NTIS)

We have continued our program of infrared (IR) photometric, imaging, spectroscopic, and polarimetric temporal observations of comets to study the properties of comet dust and comet nuclei. During the first two years we digitized our IR data base on P/Hall...

R. D. Gehrz

1997-01-01

256

Principal components analysis and neural network implementation of photometric stereo  

Microsoft Academic Search

An implementation of photometric stereo is described in which all directions of illumination are close to the viewing direction. This has practical importance but creates a numerical problem that is ill-conditioned. Ill-conditioning is dealt with in two ways. First, many more than the theoretical minimum number of required images are acquired. Second, principal components analysis (PCA) is used as a

Yuji Iwahori; Robert J. Woodham; Ardeshir Bagheri

1995-01-01

257

The INT Photometric HSurvey of the Northern Galactic Plane (IPHAS)  

Microsoft Academic Search

The INT Photometric HSurvey of the Northern Galactic Plane (IPHAS) is a 1800 square degrees CCD survey of the northern Milky Way spanning the latitude range ?5o < b < +5o and reaching down to r' ? 20 (10?). It may increase the number of known northern emission line sources by an order of magnitude. Representative observations and an assessment

Janet E. Drew; R. Greimel; M. J. Irwin; A. Aungwerojwit; M. J. Barlow; R. L. M. Corradi; J. J. Drake; B. T. Gansicke; P. Groot; A. Hales; E. C. Hopewell; J. Irwin; C. Knigge; P. Leisy; D. J. Lennon; A. Mampaso; M. R. W. Masheder; M. Matsuura; L. Morales-Rueda; R. A. H. Morris; Q. A. Parker; S. Phillipps; P. Rodriguez-Gil; G. Roelofs; I. Skillen; J. L. Sokoloski; D. Steeghs; Y. C. Unruh; K. Viironen; J. S. Vink; N. A. Walton; A. Witham; N. Wright; A. A. Zijlstra; A. Zurita

2007-01-01

258

Photometric Period of V1974 Cygni (Nova Cygni 1992).  

National Technical Information Service (NTIS)

We present the discovery of the photometric (orbital) period for V1974 Cygni (Nova Cygni 1992). The orbital period of 0.081263 +/- 0.000003 days places this classical nova just below the cataclysmic variable (CV) period gap. The modulation is driven by ir...

J. A. DeYoung R. E. Schmidt

1994-01-01

259

Tracing the sound horizon scale with photometric redshift surveys  

Microsoft Academic Search

We propose a new method for the extraction cosmological parameters using the baryon acoustic oscillation (BAO) scale as a standard ruler in deep galaxy surveys with photometric determination of redshifts. The method consists in a simple empirical parametric fit to the angular two-point correlation function omega(theta). It is parametrized as a power law to describe the continuum and as a

E. Sánchez; A. Carnero; J. García-Bellido; E. Gaztañaga; F. de Simoni; M. Crocce; A. Cabré; P. Fosalba; D. Alonso

2011-01-01

260

Tracing The Sound Horizon Scale With Photometric Redshift Surveys  

Microsoft Academic Search

We propose a new method for cosmological parameters extraction using the baryon acoustic oscillation scale as a standard ruler in deep galaxy surveys with photometric determination of redshifts. The method consists in a simple empirical parametric fit to the angular 2-point correlation function w(theta). It is parametrized as a power law to describe the continuum plus a Gaussian to describe

E Sanchez; A Carnero; J Garcia-Bellido; E Gaztanaga; F de Simoni; M Crocce; A Cabre; P Fosalba; D Alonso

2010-01-01

261

Photometric Profiles of Nearby Early-Type Galaxies Using SDSS  

NASA Astrophysics Data System (ADS)

The outer regions of galaxies provide information about their assembly histories. We are carrying out a detailed analysis of the Sloan Digital Sky Survey (SDSS) photometric profiles of a large sample of nearby early-type galaxies, in order to look for transitions between their inner and outer properties. Here we present initial results from this survey.

Johnson, Beth; Romanowsky, Aaron J.

2014-06-01

262

Designing photometric patterns for exoplanet transit search on board COROT  

Microsoft Academic Search

COROT is a mission of the CNES space agency, to be launched in 2005 in a near Polar orbit. It is devoted to star seismology and to exoplanetary transit search. Five star fields chosen close to the galactic plane will be observed during the mission with a high photometric accuracy (relative). Each observation run will last 150 days monitoring continuously

Antoine Llebaria; Andre Vuillemin; P. Guterman; Pierre Barge

2002-01-01

263

The Palomar Transient Factory photometric catalog 1.0  

NASA Astrophysics Data System (ADS)

We constructed a photometrically calibrated catalog of non-variable sources from the Palomar Transient Factory (PTF) observations. The first version of this catalog presented here, the PTF photometric catalog 1.0, contains calibrated RPTF-filter magnitudes for ?2.1 times; 107 sources brighter than magnitude 19, over an area of ?11,233 deg2. The magnitudes are provided in the PTF photometric system, and the color of a source is required in order to convert these magnitudes into other magnitude systems. We estimate that the magnitudes in this catalog have a typical accuracy of about 0.02 mag with respect to magnitudes from the Sloan Digital Sky Survey. The median repeatability of our catalog''s magnitudes for stars between 15 and 16 mag, is about 0.01 mag and it is over 0.03 mag for 95% of the sources in this magnitude range. The main goal of this catalog is to provide reference magnitudes for photometric calibration of visible light observations. Subsequent versions of this catalog, which will be published incrementally online, will be extended to cover a larger sky area and will also include gPTF-filter magnitudes, as well as variability and proper-motion information.

Ofek, E. O.; Laher, R.; Surace, J.; Levitan, D.; Sesar, B.; Horesh, A.; Law, N.; van Eyken, J. C.; Kulkarni, S. R.; Prince, T. A.; Nugent, P.; Sullivan, M.; Yaron, O.; Pickles, A.; Agüeros, M.; Arcavi, I.; Bildsten, L.; Bloom, J.; Cenko, S. B.; Gal-Yam, A.; Grillmair, C.; Helou, G.; Kasliwal, M. M.; Poznanski, D.; Quimby, R.

2012-08-01

264

Calibration of the LSST instrumental and atmospheric photometric passbands  

Microsoft Academic Search

The Large Synoptic Survey Telescope (LSST) will continuously image the entire sky visible from Cerro Pachon in northern Chile every 3-4 nights throughout the year. The LSST will provide data for a broad range of science investigations that require better than 1% photometric precision across the sky (repeatability and uniformity) and a similar accuracy of measured broadband color. The fast

David L. Burke; T. Axelrod; Aurélien Barrau; Sylvain Baumont; Stéphane Blondin; Charles Claver; Alexia Gorecki; Zeljko Ivezic; Lynne Jones; Victor Krabbendam; Ming Liang; Abhijit Saha; Allyn Smith; R. Christopher Smith; Christopher W. Stubbs; Christophe Vescovi

2010-01-01

265

Calibration of LSST Instrumental and Atmospheric Photometric Passbands  

Microsoft Academic Search

The Large Synoptic Survey Telescope (LSST) will continuously image the entire sky visible from Cerro Pachon in northern Chile every 3-4 nights throughout the year. The LSST will provide data for a broad range of science investigations that require better than 1% photometric precision across the sky (repeatability and uniformity) and a similar accuracy of measured broadband color. The fast

David L. Burke; T. Axelrod; Aurelien Barrau; Sylvain Baumont; Stephane Blondin; Chuck Claver; Alexia Gorecki; Zeljko Ivezic; Lynne Jones; Victor Krabbendam; Ming Liang; Abhijit Saha; Allyn Smith; R. Chris Smith; Christopher W. Stubbs

2011-01-01

266

Photometric Observations of a Trojan Asteroid 624 Hektor  

NASA Astrophysics Data System (ADS)

Photometric Observations for 624 Hektor were obtained in the period from 2008 December to 2012 January at the Hamanowa Astronomical Observatory using a 0.4-m Pellow reflector. The derived synodic real rotation period for lightcurves was 0.2883520(±0.0000003) day.

Hamanowa, H.; Hamanowa, H.

2012-05-01

267

Polynucleotide phosphorylase-based photometric assay for inorganic phosphate  

Microsoft Academic Search

Polynucleotide phosphorylase is a prokaryotic enzyme that catalyzes phosphorolysis of polynucleotides with release of nucleotide diphosphates. By taking advantage of this property, we developed a photometric assay for inorganic phosphate. In the presence of polyadenylic acid, phosphate is converted into adenosine 5?-diphosphate (ADP) by this enzyme. ADP then reacts with phosphoenolpyruvate in a pyruvate kinase-catalyzed reaction, thus giving rise to

Andrea Ghetta; Maura Matus-Ortega; Jaime Garc??a-Mena; Gianni Dehò; Paolo Tortora; Maria Elena Regonesi

2004-01-01

268

The Young Solar Analogs Project: Initial Photometric Results  

NASA Astrophysics Data System (ADS)

Since 2007 we have been conducting spectroscopic monitoring of the Ca II H & K lines and G-band for a sample of 31 YSAs in order to better understand their activity cycles and variations, as well as the effects of young stars on their solar systems. The targets cover the spectral range of stars most likely to contain Earth analogs, F8-K2, and a broad enough range of ages, 0.3 Gyr - 1.5 Gyr, to investigate how activity level changes with stellar age. These studies are already showing possible evidence for activity cycles, large variations in starspot activity, and flaring events. In order to obtain a more complete picture of the nature of the stars' activity and examine the correlations between stellar brightness and chromospheric activity, we have started a complimentary campaign of photometric monitoring of these targets in Johnson B, V, and R, Stromgren v and H-alpha, with the use of a small robotic telescope dedicated to this project. This poster will present some results from the first year of photometric monitoring, focusing on the correlations between the photometric bands, and between the photometric and spectroscopic data, as well as an investigation of short-term (1-2 minutes) spectroscopic variations using data obtained earlier this year on the 1.8 m Vatican Advanced Technology Telescope (VATT).

Saken, Jon M.; Gray, R. O.; Corbally, C. J.

2013-06-01

269

21 CFR 862.2160 - Discrete photometric chemistry analyzer for clinical use.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 false Discrete photometric chemistry analyzer for clinical use. 862.2160...CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical... § 862.2160 Discrete photometric chemistry analyzer for clinical use. (a)...

2012-04-01

270

21 CFR 862.2160 - Discrete photometric chemistry analyzer for clinical use.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Discrete photometric chemistry analyzer for clinical use. 862.2160...CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical... § 862.2160 Discrete photometric chemistry analyzer for clinical use. (a)...

2010-04-01

271

21 CFR 862.2160 - Discrete photometric chemistry analyzer for clinical use.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 false Discrete photometric chemistry analyzer for clinical use. 862.2160...CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical... § 862.2160 Discrete photometric chemistry analyzer for clinical use. (a)...

2009-04-01

272

Whipple Procedure  

MedlinePLUS

... Lab Sol Goldman Center Discussion Board The Whipple Procedure Also called a pancreaticoduodenectomy, which is generally the ... have been many modifications and improvements of the procedure. There is a detailed account of the operative ...

273

Checkout Procedures.  

National Technical Information Service (NTIS)

The reliable performance of some oceanographic instruments is dependent on proper checkout procedures. The Reliability Division of the National Oceanographic Instrumentation Center develops checkout procedures when necessary and disseminates them througho...

1971-01-01

274

Photodigitizing procedures  

Microsoft Academic Search

This report documents procedures and programs for efficiently running the Photo Digitizing System at the Naval Biodynamics Laboratory. Procedures have been tested and have been found to be effective. Any future acquisitions of programs or changes to current programs should be incorporated in these procedures. On-going research programs use high speed instrumentation cameras to record the motion of test subjects

P. D. Kilgore; J. H. Gottbrath

1984-01-01

275

PHOTOMETRIC SUPERNOVA COSMOLOGY WITH BEAMS AND SDSS-II  

SciTech Connect

Supernova (SN) cosmology without spectroscopic confirmation is an exciting new frontier, which we address here with the Bayesian Estimation Applied to Multiple Species (BEAMS) algorithm and the full three years of data from the Sloan Digital Sky Survey II Supernova Survey (SDSS-II SN). BEAMS is a Bayesian framework for using data from multiple species in statistical inference when one has the probability that each data point belongs to a given species, corresponding in this context to different types of SNe with their probabilities derived from their multi-band light curves. We run the BEAMS algorithm on both Gaussian and more realistic SNANA simulations with of order 10{sup 4} SNe, testing the algorithm against various pitfalls one might expect in the new and somewhat uncharted territory of photometric SN cosmology. We compare the performance of BEAMS to that of both mock spectroscopic surveys and photometric samples that have been cut using typical selection criteria. The latter typically either are biased due to contamination or have significantly larger contours in the cosmological parameters due to small data sets. We then apply BEAMS to the 792 SDSS-II photometric SNe with host spectroscopic redshifts. In this case, BEAMS reduces the area of the {Omega}{sub m}, {Omega}{sub {Lambda}} contours by a factor of three relative to the case where only spectroscopically confirmed data are used (297 SNe). In the case of flatness, the constraints obtained on the matter density applying BEAMS to the photometric SDSS-II data are {Omega}{sup BEAMS}{sub m} = 0.194 {+-} 0.07. This illustrates the potential power of BEAMS for future large photometric SN surveys such as Large Synoptic Survey Telescope.

Hlozek, Renee [Oxford Astrophysics, Department of Physics, University of Oxford, Keble Road, Oxford, OX1 3RH (United Kingdom); Kunz, Martin [Department de physique theorique, Universite de Geneve, 30, quai Ernest-Ansermet, CH-1211 Geneve 4 (Switzerland); Bassett, Bruce; Smith, Mat; Newling, James [African Institute for Mathematical Sciences, 68 Melrose Road, Muizenberg 7945 (South Africa); Varughese, Melvin [Department of Mathematics and Applied Mathematics, University of Cape Town, Rondebosch, Cape Town, 7700 (South Africa); Kessler, Rick; Frieman, Joshua [The Kavli Institute for Cosmological Physics, The University of Chicago, 933 East 56th Street, Chicago, IL 60637 (United States); Bernstein, Joseph P.; Kuhlmann, Steve; Marriner, John [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Campbell, Heather; Lampeitl, Hubert; Nichol, Robert C. [Institute of Cosmology and Gravitation, Dennis Sciama Building Burnaby Road Portsmouth PO1 3FX (United Kingdom); Dilday, Ben [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Goleta, CA 93117 (United States); Falck, Bridget; Riess, Adam G. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Sako, Masao [Department of Physics and Astronomy, University of Pennsylvania, 203 South 33rd Street, Philadelphia, PA 19104 (United States); Schneider, Donald P., E-mail: rhlozek@astro.princeton.edu [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States)

2012-06-20

276

Flame photometric determination of strontium in water  

USGS Publications Warehouse

Preliminary search of reported methods of Sr analysis revealed several investigations which have been made for the determination of Sr with the flame photometer, both at relatively low concentrations (0 to 50 ppm Sr) and at higher concentrations. Generally the procedures described involved measurement of Sr emission at either 460.7 mu or at 681 mu. There is disagreement among those reporting methods for Sr as to the preference of the one wavelength over the other. The 681 line (or band) seems to be preferred because of its greater reproducibility and relative freedom from interference. The 460.7 mu line, however, lies in the region of greater sensitivity of the photomultiplier tube, and hence for this reason is preferred by some. This is an advantage, of course, when determining Sr at very low concentrations. This investigation is concerned with determining the optimum conditions for the determination of Sr at low concentration levels in water samples. Early experimental work indicated a greater sensitivity for the 460.7 mu (hereafter designated as 461 mu) Sr line. Therefore, most of the subsequent work was based on a study of the effects of various other materials and conditions on the emission of Sr at this wavelength.

Skougstad, Marvin W.

1957-01-01

277

Ascorbic Acid as a Standard for Iodometric Titrations. An Analytical Experiment for General Chemistry  

NASA Astrophysics Data System (ADS)

Ascorbic acid is suggested as the weighable compound for the standardization of iodine solutions in an analytical experiment in general chemistry. The experiment involves an iodometric titration in which iodine reacts with ascorbic acid, oxidizing it to dehydroascorbic acid. The redox titration endpoint is determined by the first iodine excess that is complexed with starch, giving a deep blue-violet color. The results of the titration of iodine solution using ascorbic acid as a calibration standard were compared with the results acquired by the classic method using a standardized solution of sodium thiosulfate. The standardization of the iodine solution using ascorbic acid was accurate and precise, with the advantages of saving time and avoiding mistakes due to solution preparation. The colorless ascorbic acid solution gives a very clear and sharp titration end point with starch. It was shown by thermogravimetric analysis that ascorbic acid can be dried at 393 K for 2 h without decomposition. This experiment allows general chemistry students to perform an iodometric titration during a single laboratory period, determining with precision the content of vitamin C in pharmaceutical formulations.

Silva, Cesar R.; Simoni, Jose A.; Collins, Carol H.; Volpe, Pedro L. O.

1999-10-01

278

Gas chromatography with flame photometric detection of 31 organophosphorus pesticide residues in Alpinia oxyphylla dried fruits.  

PubMed

A simple, rapid and effective gas chromatography-flame photometric detection method was established for simultaneous multi-component determination of 31 organophosphorus pesticides (OPPs) residues in Alpinia oxyphylla, which is widely consumed as a traditional medicine and food in China. Sample preparation was completed in a single step without any clean-up procedure. All pesticides expressed good linear relationships between 0.004 and 1.0?g/mL with correlation coefficients higher than 0.9973. The method gave satisfactory recoveries for most pesticides. The limits of detection varied from 1 to 10ng/mL, and the limits of quantification (LOQs) were between 4 and 30ng/mL. The proposed method was successfully applied to 55 commercial samples purchased from five different areas. Five pesticide residues were detected in four (7.27%) samples. The positive samples were confirmed by gas chromatography with tandem mass spectrometry (GC-MS/MS). PMID:24874387

Zhao, Xiangsheng; Kong, Weijun; Wei, Jianhe; Yang, Meihua

2014-11-01

279

Determination of the point-of-zero, charge of manganese oxides with different methods including an improved salt titration method  

Microsoft Academic Search

Manganese (Mn) oxides are important components in soils and sediments. Points-of-zero charge (PZC) of three synthetic Mn oxides (birnessite, cryptomelane, and todorokite) were determined by using three classical techniques (potentiometric titration or PT, rapid PT or R-PT, and salt titration or ST) and a modified salt titration method with a prolonged equilibration time (ST method with a prolonged equilibration time

Wen-feng Tan; Si-jun Lu; Fan Liu; Xiong-han Feng; Ji-zheng He; Luuk K. Koopal

2008-01-01

280

Determination of sulphated glycosaminoglycans by automated potentiometric titration with simple coated-wire electrodes.  

PubMed

A method for the determination of sulphated glycosaminoglycans is based on their precipitation with (1-ethoxycarbonyl)pentadecyltrimethylammonium bromide (Septonex), the excess of which is back-titrated with sodium tetraphenylborate. The titration is monitored by a simple coated-wire ion-selective electrode with a plasticized poly(vinyl chloride) membrane on aluminium wire. Under certain conditions the results are almost independent of the relative molecular mass of glycosaminoglycans. The method has been applied to the determination of the active ingredient in the pharmaceutical preparation, heparon injection. PMID:2490091

Dohnal, J; Vytras, K; Roubal, Z; Zemanová, I

1989-01-01

281

Rapid carvedilol up-titration in hospitalized patients with systolic heart failure.  

PubMed

To determine whether carvedilol can be safely up-titrated before hospital discharge, we studied 372 consecutive patients with systolic heart failure who were being treated with carvedilol. Carvedilol was initiated a median of 3 days after admission, with a mean starting dose of 12 mg. Up-titration was performed in 67% of patients, with a mean increase of 16 mg and a mean discharge daily dose of 23 +/- 17 mg. Mean daily dose at the end of follow-up was 35.3 +/- 25.3 mg and it increased with higher discharge dose. PMID:18656807

Martínez-Sellés, Manuel; Datino, Tomás; Alhama, Marta; Barrueco, Nelida; Castillo, Isabel; Fernández-Avilés, Francisco

2008-08-01

282

Selective two-step titration of thorium by sulfate displacement of the diethylenetriaminepentaacetic acid complex  

SciTech Connect

Thorium and other metals are complexed with excess diethylenetriaminepentaacetic acid (DTPA) at pH 1.4, the excess DTPA is titrated with Bi(III) to a xylenol orange end point, sulfate is added to complex Th(IV), and the displaced DTPA again is titrated with Bi(III). Of 61 metal ions and nonmetal anions tested, only Ga(III), Sc(III), tungstate, citrate, oxalate, and thiosulfate interfere seriously. Lesser interferences are In(III), Zr(IV), V(IV), and permanganate. The standard deviation is 2 ..mu..g for 56 to 840 ..mu..g Th.

Kiefer, P.

1980-07-01

283

Specification of colour changes of metallochromic indicators in the titration of bismuth with EDTA.  

PubMed

The quality of the colour changes at the end-point in the complexometric titration of bismuth(III) with EDTA, using the indicators Hemotoxylin, PAN [1-(2-Pyridylazo)-Naphthol-2], PAR [4-(2-Pyridylazo)-Resorcinol], Xylenol Orange and Thoran is studied by means of the CIE 1931 trichromatic system, using specific colour discrimination (SCD) and colour difference (DeltaE*). The indicators are arranged in order of colour change quality. Of the indicators studied, Hemotoxylin is recommended as the most suitable for this titration. PMID:18965223

Prasad, K M; Raheem, S

1991-07-01

284

Joint blind restoration and surface recovery in photometric stereo  

NASA Astrophysics Data System (ADS)

We address the problem of simultaneous estimation of scene structure and restoration of images from blurred photometric measurements. In photometric stereo, the structure of an object is determined by using a particular reflectance model (the image irradiance equation) without considering the blurring effect. What we show is that, given arbitrarily blurred observations of a static scene captured with a stationary camera under different illuminant directions, we still can obtain the structure represented by the surface gradients and the albedo and also perform a blind image restoration. The surface gradients and the albedo are modeled as separate Markov random fields, and a suitable regularization scheme is used to estimate the different fields as well as the blur parameter. The results of the experimentations are illustrated with real as well as synthetic images.

Joshi, Manjunath V.; Chaudhuri, Subhasis

2005-06-01

285

KEPLER MISSION DESIGN, REALIZED PHOTOMETRIC PERFORMANCE, AND EARLY SCIENCE  

SciTech Connect

The Kepler Mission, launched on 2009 March 6, was designed with the explicit capability to detect Earth-size planets in the habitable zone of solar-like stars using the transit photometry method. Results from just 43 days of data along with ground-based follow-up observations have identified five new transiting planets with measurements of their masses, radii, and orbital periods. Many aspects of stellar astrophysics also benefit from the unique, precise, extended, and nearly continuous data set for a large number and variety of stars. Early results for classical variables and eclipsing stars show great promise. To fully understand the methodology, processes, and eventually the results from the mission, we present the underlying rationale that ultimately led to the flight and ground system designs used to achieve the exquisite photometric performance. As an example of the initial photometric results, we present variability measurements that can be used to distinguish dwarf stars from red giants.

Koch, David G.; Borucki, William J.; Lissauer, Jack J. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Basri, Gibor; Marcy, Geoffrey [Department of Astronomy, University of California-Berkeley, Berkeley, CA 94720 (United States); Batalha, Natalie M. [Department of Physics and Astronomy, San Jose State University, San Jose, CA 95192 (United States); Brown, Timothy M. [Las Cumbres Observatory Global Telescope, Goleta, CA 93117 (United States); Caldwell, Douglas; DeVore, Edna; Jenkins, Jon [SETI Institute, NASA Ames Research Center, Moffett Field, CA 94035 (United States); Christensen-Dalsgaard, Joergen [Aarhus University, DK-8000, Aarhus C (Denmark); Cochran, William D. [McDonald Observatory, University of Texas at Austin, Austin, TX 78712 (United States); Dunham, Edward W. [Lowell Observatory, Flagstaff, AZ 86001 (United States); Gautier, Thomas N. [Jet Propulsion Laboratory/California Institute of Technology, Pasadena, CA 91109 (United States); Geary, John C.; Latham, David W. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Gilliland, Ronald L. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Gould, Alan [Lawarence Hall of Science, University of California-Berkeley, Berkeley, CA 94720 (United States); Kondo, Yoji [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Monet, David [United States Naval Observatory, Flagstaff, AZ 86002 (United States)], E-mail: D.Koch@NASA.gov (and others)

2010-04-20

286

The photometric method of detecting other planetary systems  

NASA Technical Reports Server (NTRS)

Rosenblatt (1971) has conducted an investigation regarding the use of photometric techniques to detect other planetary systems by searching for changes in starlight caused by the transit of a planet. The obtained results suggest that neither the intrinsic variation of the starlight nor the transmission fluctuations in the terrestrial atmosphere would prevent detection of planets as small as Mars with telescope apertures of 40 to 60 cm. The present investigation shows that Rosenblatt's results are too optimistic even for present-day differential photometric techniques. However, it appears that the detection of planets at least one-third the size of Jupiter is feasible, if a photometer with the required precision can be developed, taking into account the availability of a wide-angle telescope with a 1- to 2-m aperture.

Borucki, W. J.; Summers, A. L.

1984-01-01

287

Observational Tests to Detect Photometric Reverberation in H-alpha  

NASA Astrophysics Data System (ADS)

We present photometric observations of several AGN that were secured with the 0.9-m telescope located at the West Mountain Observatory that is operated by Brigham Young University. The new observations use standard BVR filters along with several custom filters that are part of a red shifted H-alpha set. Light curves are presented for several of the targets along with a summary of the analysis made to detect lag times between the continuum and broad emission line flux as evidence for photometric reverberation. Plans are presented for future research that will continue along these lines.We thank the Department of Physics and Astronomy along with the College of Physical and Mathematical Sciences at Brigham Young University for continued support of the research work being done at the West Mountain Observatory.

Joner, Michael D.; Carroll, Carla

2014-06-01

288

Photometric and Polarimetric Opposition Phenomena Exhibited by Solar System Bodies  

NASA Astrophysics Data System (ADS)

Ground-based and spacecraft observations of atmosphereless solar system bodies (planets, satellites, planetary rings, and asteroids) and cometary and interplanetary dust particles have provided a wealth of new photometric and polarimetric data over a wide range of phase angles and wavelengths. This chapter reviews the progress in the study of the photometric and polarimetric phase effects observed near opposition. We also present the results of recent polarimetric observations of the Galilean satellites of Jupiter, Iapetus, and the asteroid 64 Angelina at very small phase angles. Analyses of the available data allowed us to determine the parameters of the brightness and polarization opposition effects and investigate correlations between them. The results obtained may form the observational basis for detailed theoretical modeling and interpretation of the phase effects.

Rosenbush, Vera; Kiselev, Nikolai; Avramchuk, Victor; Mishchenko, Michael

289

SN 1988Z: spectro-photometric catalogue and energy estimates  

Microsoft Academic Search

We present a spectro-photometric catalogue of the evolution of supernova 1988Z, which combines new and published observations in the radio, optical and X-ray bands, with the aim of offering a comprehensive view of the evolution of this object and deriving the total energy radiated since its discovery. The major contribution to the total radiated energy comes at optical to X-ray

Itziar Aretxaga; S. Benetti; R. J. Terlevich; A. C. Fabian; E. Cappellaro; M. Turatto; M. della Valle

1999-01-01

290

Recovering discontinuous surfaces with photometric stereo and laser sectioning  

NASA Astrophysics Data System (ADS)

Surfaces that are recovered by integrating slope estimates are prone to errors caused by discontinuities in the surface. We propose combining laser sectioning and photometric stereo (PS) to estimate surface shape. PS is used to estimate slope; laser lines are used to measure four height profiles. The slopes are integrated along paths that start from the laser height profiles and avoid discontinuities. The scheme is shown to mitigate the bias and surface discontinuity problems associated with PS.

McGunnigle, Gerald; Dong, Junyu; Su, Liyuan; Fang, Yanxia

2011-05-01

291

Microdensitometer errors: Their effect on photometric data reduction  

NASA Technical Reports Server (NTRS)

The performance of densitometers used for photometric data reduction of high dynamic range electrographic plate material is analyzed. Densitometer repeatability is tested by comparing two scans of one plate. Internal densitometer errors are examined by constructing histograms of digitized densities and finding inoperative bits and differential nonlinearity in the analog to digital converter. Such problems appear common to the four densitometers used in this investigation and introduce systematic algorithm dependent errors in the results. Strategies to improve densitometer performance are suggested.

Bozyan, E. P.; Opal, C. B.

1984-01-01

292

The Impact of Stochastic Attenuation on Photometric Redshift Estimates  

NASA Astrophysics Data System (ADS)

INTRODUCTION: We model the effect of the stochastic absorption by neutral hydrogen (HI) present in the intergalactic medium (IGM), such as Lyalpha Forest, and associated with galaxies (LLS, DLAs), on the photometric redshifts, and compare these results to the predicted photometric redshifts of models where only a mean attenuation is taken into account. METHODS: We model the attenuation due to HI along a random line of sight (LOS) using differential distribution functions constrained from observations (Kim et al. 97,01) in a Monte Carlo fashion (Bershady et al. 99). We then calculate galaxy model spectra of a given spectral type at different redshifts using our Evolutionary Synthesis Code GALEV (Bicker et al. 04), and apply to each spectrum a different attenuation corresponding to a particular random LOS. We obtain in this way an ensemble of attenuated spectral energy distributiond (SED) in the HST and Johnson systems. Using AnalySED (Anders et al. 06), an analysis tool based on a chi-square test, and our template SEDs with mean attenuation-which span a grid in redshift and spectral type-we determine to which extent the redshifts of our simulated spectra are recovered. RESULTS: We find a substantial underestimate of the photometric redshifts of up to ?z=0.3, especially in the range z > 3.0. DISCUSSION: Based on our results, we emphasise the need for the accurate modelling of the attenuation in order to correctly interpret, using evolutionary synthesis codes such as GALEV, the observations of (high-redshift) galaxies observed in deep surveys, for which only photometric information is available.

Tepper-García, Thorsten; Fritze-von Alvensleben, Uta

2007-05-01

293

Some photometric techniques for atmosphereless solar system bodies.  

PubMed

We discuss various photometric techniques and their absolute scales in relation to the information that can be derived from the relevant data. We also outline a new scattering model for atmosphereless bodies in the solar system and show how it fits Mariner 10 surface photometry of the planet Mercury. It is shown how important the correct scattering law is while deriving the topography by photoclinometry. PMID:11538682

Lumme, K; Peltoniemi, J; Irvine, W M

1990-01-01

294

ESO & NOT photometric monitoring of the Cloverleaf quasar  

NASA Astrophysics Data System (ADS)

The Cloverleaf quasar, H1413+117, has been photometrically monitored at ESO (La Silla, Chile) and with the NOT (La Palma, Spain) during the period 1987--1994. All good quality CCD frames have been successfully analysed using two independent methods (i.e. an automatic image decomposition technique and an interactive CLEAN algorithm). The photometric results from the two methods are found to be very similar, and they show that the four lensed QSO images vary significantly in brightness (by up to 0.45 mag), nearly in parallel. The lightcurve of the $D$ component presents some slight departures from the general trend which are very likely caused by micro-lensing effects. Upper limits, at the 99% confidence level, of 150 days on the absolute value for the time delays between the photometric lightcurves of this quadruply imaged variable QSO, are derived. This is unfortunately too large to constrain the lens model but there is little doubt that a better sampling of the lightcurves should allow to accurately derive these time delays. Pending a direct detection of the lensing galaxy (position and redshift), this system thus constitutes another good candidate for a direct and independent determination of the Hubble parameter. Based on observations collected at the European Southern Observatory (La Silla, Chile) and with the Nordic Optical Telescope (La Palma, Spain). Table 1. Logbook for the ESO and NOT observations together with photometric results for the Cloverleaf quasar. This long table can be accessed on the WWW at the URL address: http://vela.astro.ulg.ac.be/grav_lens/glp_homepage.html}

Ostensen, R.; Remy, M.; Lindblad, P. O.; Refsdal, S.; Stabell, R.; Surdej, J.; Barthel, P. D.; Emanuelsen, P. I.; Festin, L.; Gosset, E.; Hainaut, O.; Hakala, P.; Hjelm, M.; Hjorth, J.; Hutsemekers, D.; Jablonski, M.; Kaas, A. A.; Kristen, H.; Larsson, S.; Magain, P.; Pettersson, B.; Pospieszalska-Surdej, A.; Smette, A.; Teuber, J.; Thomsen, B.; van Drom, E.

1997-12-01

295

Separating Specular, Diffuse, and Subsurface Scattering Reflectances from Photometric Images  

Microsoft Academic Search

While subsurface scattering is common in many real objects, almost all sepa- ration algorithms focus on extracting specular and diffuse components from real images. In this paper, we propose an appearance-based approach to separate non-directional sub- surface scattering reectance from photometric images, in addition to the separation of the off-specular and non-Lambertian diffuse components. Our mathematical model suf- ciently accounts

Tai-pang Wu; Chi-keung Tang

2004-01-01

296

Photometric recording of transmembrane potential in outer hair cells  

NASA Astrophysics Data System (ADS)

Cochlear outer hair cells (OHCs) are polarized epithelial cells that have mechanoelectrical transduction channels within their apical stereocilia and produce electromotile force along their lateral wall. Phase shifts, or time delays, in the transmembrane voltage occurring at different axial locations along the cell may contribute to our understanding of how these cells operate at auditory frequencies. We developed a method to optically measure the phase of the OHC transmembrane potential using the voltage-sensitive dye (VSD) di-8-ANEPPS. The exit aperture of a fibre-optic light source was driven in two dimensions so that a 24 µm spot of excitation light could be positioned along the length of the OHC. We used the whole-cell patch-clamp technique in the current-clamp mode to stimulate the OHC at the base. The photometric response and the voltage response were monitored with a photodetector and patch-clamp amplifier, respectively. The photometric response was used to measure the regional changes in the membrane potential in response to maintained (dc) and sinusoidal (ac) current stimuli applied at the base of the cell. We used a neutral density filter to lower the excitation light intensity and reduce phototoxicity. A sensitive detector and lock-in amplifier were used to measure the small ac VSD signal. This permitted measurements of the ac photometric response below the noise floor of the static fluorescence. The amplitude and phase components of the photometric response were recorded for stimuli up to 800 Hz. VSD data at 400-800 Hz show the presence of a small phase delay between the stimulus voltage at the base of the cell and the local membrane potential measured along the lateral wall. Results are consistent with the hypothesis that OHCs exhibit inhomogeneous membrane potentials that vary with position in analogy with the voltage in nerve axons.

Nakagawa, Takashi; Oghalai, John S.; Saggau, Peter; Rabbitt, Richard D.; Brownell, William E.

2006-06-01

297

Photometric recording of transmembrane potential in outer hair cells  

PubMed Central

Cochlear outer hair cells (OHCs) are polarized epithelial cells that have mechanoelectrical transduction channels within their apical stereocilia and produce electromotile force along their lateral wall. Phase shifts, or time delays, in the transmembrane voltage occurring at different axial locations along the cell may contribute to our understanding of how these cells operate at auditory frequencies. We developed a method to optically measure the phase of the OHC transmembrane potential using the voltage-sensitive dye (VSD) di-8-ANEPPS. The exit aperture of a fibre-optic light source was driven in two dimensions so that a 24 ?m spot of excitation light could be positioned along the length of the OHC. We used the whole-cell patch-clamp technique in the current-clamp mode to stimulate the OHC at the base. The photometric response and the voltage response were monitored with a photodetector and patch-clamp amplifier, respectively. The photometric response was used to measure the regional changes in the membrane potential in response to maintained (dc) and sinusoidal (ac) current stimuli applied at the base of the cell. We used a neutral density filter to lower the excitation light intensity and reduce phototoxicity. A sensitive detector and lock-in amplifier were used to measure the small ac VSD signal. This permitted measurements of the ac photometric response below the noise floor of the static fluorescence. The amplitude and phase components of the photometric response were recorded for stimuli up to 800 Hz. VSD data at 400–800 Hz show the presence of a small phase delay between the stimulus voltage at the base of the cell and the local membrane potential measured along the lateral wall. Results are consistent with the hypothesis that OHCs exhibit inhomogeneous membrane potentials that vary with position in analogy with the voltage in nerve axons.

Nakagawa, Takashi; Oghalai, John S; Saggau, Peter; Rabbitt, Richard D; Brownell, William E

2008-01-01

298

Photometric investigation of dark clouds in the solar vicinity.  

NASA Astrophysics Data System (ADS)

Distances of nine groups of dark clouds are determined using the extinction vs. distance plots obtained with the help of the Vilnius photometric system. The investigated areas include four directions in the Taurus dark clouds, two directions in the Perseus dark clouds, the cloud around the reflection nebula NGC 7023 in Cepheus, the cloud at the North American and Pelican nebula, and the Scorpio-Ophiuchus dark cloud.

Meistas, E.; ?ernis, K.; Straižys, V.

299

The SDSS Coadd: A Galaxy Photometric Redshift Catalog  

Microsoft Academic Search

We present and describe a catalog of galaxy photometric redshifts (photo-z's) for the Sloan Digital Sky Survey (SDSS) Coadd Data. We use the Artificial Neural Network (ANN) technique to calculate photo-z's and the Nearest Neighbor Error (NNE) method to estimate photo-z errors for 13 million objects classified as galaxies in the coadd with r < 24.5. The photo-z and photo-z

Ribamar R. R. Reis; Marcelle Soares-Santos; James Annis; Scott Dodelson; Jiangang Hao; David Johnston; Jeffrey Kubo; Huan Lin; Hee-Jong Seo; Melanie Simet

2011-01-01

300

Measuring redshift-space distortions using photometric surveys  

Microsoft Academic Search

We outline how redshift-space distortions (RSD) can be measured from the angular correlation function, w(theta), of galaxies selected from photometric surveys. The natural degeneracy between RSD and galaxy bias can be minimized by comparing results from bins with top-hat galaxy selection in redshift, and bins based on the radial position of galaxy pair centres. This comparison can also be used

Ashley J. Ross; Will J. Percival; Martín Crocce; Anna Cabré; Enrique Gaztañaga

2011-01-01

301

Exhausting the information: novel Bayesian combination of photometric redshift PDFs  

NASA Astrophysics Data System (ADS)

The estimation and utilization of photometric redshift probability density functions (photo-z PDFs) have become increasingly important over the last few years and currently there exist a wide variety of algorithms to compute photo-z's, each with their own strengths and weaknesses. In this paper, we present a novel and efficient Bayesian framework that combines the results from different photo-z techniques into a more powerful and robust estimate by maximizing the information from the photometric data. To demonstrate this, we use a supervised machine learning technique based on random forest, an unsupervised method based on self-organizing maps, and a standard template-fitting method but can be easily extended to other existing techniques. We use data from the DEEP2 survey and the Sloan Digital Sky Survey to explore different methods for combining the predictions from these techniques. By using different performance metrics, we demonstrate that we can improve the accuracy of our final photo-z estimate over the best input technique, that the fraction of outliers is reduced, and that the identification of outliers is significantly improved when we apply a naïve Bayes classifier to this combined information. Our more robust and accurate photo-z PDFs will allow even more precise cosmological constraints to be made by using current and future photometric surveys. These improvements are crucial as we move to analyse photometric data that push to or even past the limits of the available training data, which will be the case with the Large Synoptic Survey Telescope.

Carrasco Kind, Matias; Brunner, Robert J.

2014-08-01

302

Photometric and polarimetric mapping of water turbidity and water depth  

NASA Technical Reports Server (NTRS)

A Digital Photometric Mapper (DPM) was used in the Fall of 1971 in an airborne survey of New York and Boston area waters to acquire photometric, spectral and polarimetric data. The object of this study is to analyze these data with quantitative computer processing techniques to assess the potential of the DPM in the measurement and regional mapping of water turbidity and depth. These techniques have been developed and an operational potential has been demonstrated. More emphasis is placed at this time on the methodology of data acquisition, analysis and display than on the quantity of data. The results illustrate the type, quantity and format of information that could be generated operationally with the DPM-type sensor characterized by high photometric stability and fast, accurate digital output. The prototype, single-channel DPM is suggested as a unique research tool for a number of new applications. For the operational mapping of water turbidity and depth, the merits of a multichannel DPM coupled with a laser system are stressed.

Halajian, J.; Hallock, H.

1973-01-01

303

Measuring the transition to homogeneity with photometric redshift surveys  

NASA Astrophysics Data System (ADS)

We study the possibility of detecting the transition to homogeneity using photometric redshift catalogues. Our method is based on measuring the fractality of the projected galaxy distribution, using angular distances, and relies only on observable quantities. It thus provides a way to test the cosmological principle in a model-independent unbiased way. We have tested our method on different synthetic inhomogeneous catalogues and shown that it is capable of discriminating some fractal models with relatively large fractal dimensions, in spite of the loss of information due to the radial projection. We have also studied the influence of the redshift bin width, photometric redshift errors, bias, non-linear clustering, and surveyed area on the angular homogeneity index H2(?) in a ? cold dark matter cosmology. The level to which an upcoming galaxy survey will be able to constrain the transition to homogeneity will depend mainly on the total surveyed area and the compactness of the surveyed region. In particular, a Dark Energy Survey (DES)-like survey should be able to easily discriminate certain fractal models with fractal dimensions as large as D2 = 2.95. We believe that this method will have relevant applications for upcoming large photometric redshift surveys, such as DES or the Large Synoptic Survey Telescope.

Alonso, D.; Bueno Belloso, A.; Sánchez, F. J.; García-Bellido, J.; Sánchez, E.

2014-05-01

304

Can Self-Organizing Maps Accurately Predict Photometric Redshifts?  

NASA Astrophysics Data System (ADS)

We present an unsupervised machine-learning approach that can be employed for estimating photometric redshifts. The proposed method is based on a vector quantization called the self-organizing-map (SOM) approach. A variety of photometrically derived input values were utilized from the Sloan Digital Sky Survey''s main galaxy sample, luminous red galaxy, and quasar samples, along with the PHAT0 data set from the Photo-z Accuracy Testing project. Regression results obtained with this new approach were evaluated in terms of root-mean-square error (RMSE) to estimate the accuracy of the photometric redshift estimates. The results demonstrate competitive RMSE and outlier percentages when compared with several other popular approaches, such as artificial neural networks and Gaussian process regression. SOM RMSE results (using ?z = zphot - zspec) are 0.023 for the main galaxy sample, 0.027 for the luminous red galaxy sample, 0.418 for quasars, and 0.022 for PHAT0 synthetic data. The results demonstrate that there are nonunique solutions for estimating SOM RMSEs. Further research is needed in order to find more robust estimation techniques using SOMs, but the results herein are a positive indication of their capabilities when compared with other well-known methods.

Way, M. J.; Klose, C. D.

2012-03-01

305

Calibrating the Strömvil Photometric System by M 67 at VATT  

NASA Astrophysics Data System (ADS)

For our observational program on stellar clusters to calibrate the Strömvil Photometric System (the four Strömgren u v b y and the three Vilnius P Z S filters), we use the Lennon Telescope (VATT) of the Vatican and Steward Observatories on Mt. Graham. We have observed the open cluster M 67 wherein much photometry both photoelectric and CCD already exists. Multiple exposures with the telescope offset by small (10 arcsec) and larger (2 arcmin) amounts and with the derotator offset by 180 degrees tell what is the photometric uncertainty attained. The flatfielding of the CCD has been significantly improved by adding black velvet inside the "top hat" baffle tube and the hole of the primary mirror in order to suppress scattered light. The multiple exposures in M 67 now show photometric error in the instrumental system of less than 0.015 mag RMS. And the transformation into the standard Strömvil System by use of stellar standards shows a successful fit to 0.015 RMS in all seven filters. Thus learning the color transformation equations we are prepared to calibrate other star fields in the Strömvil System for stellar classification.

Boyle, R. P.; Philip, A. G. Davis; Smriglio, F.; Dasgupta, A.; Kazlauskas, A.; Straižys, V.

2000-12-01

306

A PHOTOMETRIC ANALYSIS OF SEVENTEEN BINARY STARS USING SPECKLE IMAGING  

SciTech Connect

Magnitude differences obtained from speckle imaging are used in combination with other data in the literature to place the components of binary star systems on the H-R diagram. Isochrones are compared with the positions obtained, and a best-fit isochrone is determined for each system, yielding both masses of the components as well as an age range consistent with the system parameters. Seventeen systems are studied, 12 of which were observed with the 0.6 m Lowell-Tololo Telescope at Cerro Tololo Inter-American Observatory and six of which were observed with the WIYN 3.5 m Telescope (The WIYN Observatory is a joint facility of the University of Wisconsin-Madison, Indiana University, Yale University, and the National Optical Astronomy Observatories) at Kitt Peak. One system was observed from both sites. In comparing photometric masses to mass information from orbit determinations, we find that the photometric masses agree very well with the dynamical masses, and are generally more precise. For three systems, no dynamical masses exist at present, and therefore the photometrically determined values are the first mass estimates derived for these components.

Davidson, James W. [Department of Physics and Astronomy, University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606-3390 (United States); Baptista, Brian J. [Department of Astronomy, Indiana University, 727 East 3rd Street, Bloomington, IN 47405-7105 (United States); Horch, Elliott P. [Department of Physics, Southern Connecticut State University, 501 Crescent Street, New Haven, CT 06515 (United States); Franz, Otto [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Van Altena, William F. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520 (United States)], E-mail: jdavid@physics.utoledo.edu, E-mail: bbapti@astro.indiana.edu, E-mail: horche2@southernct.edu, E-mail: Otto.Franz@lowell.edu, E-mail: william.vanaltena@yale.edu

2009-11-15

307

Photometric monitoring of the young star Par 1724 in Orion  

NASA Astrophysics Data System (ADS)

We report new photometric observations of the ˜ 200 000 year old naked weak-line run-away T Tauri star Par 1724, located north of the Trapezium cluster in Orion. We observed in the broad band filters B, V, R, and I using the 90 cm Dutch telescope on La Silla, the 80 cm Wendelstein telescope, and a 25 cm telescope of the University Observatory Jena in Großschwabhausen near Jena. The photometric data in V and R are consistent with a ˜ 5.7 day rotation period due to spots, as observed before between 1960ies and 2000. Also, for the first time, we present evidence for a long-term 9 or 17.5 year cycle in photometric data (V band) of such a young star, a cycle similar to that to of the Sun and other active stars. Based on observations obtained with telescopes of the University Observatory Jena, which is operated by the Astrophysical Institute of the Friedrich-Schiller-University; a telescope of the University Observatory Munich on Mount Wendelstein, the 0.9m ESO-Dutch telescope on La Silla, Chile, and with the All Sky Automated Survey (ASAS) project (www.astrouw.edu.pl/asas).

Neuhäuser, R.; Koeltzsch, A.; Raetz, St.; Schmidt, T. O. B.; Mugrauer, M.; Young, N.; Bertoldi, F.; Roell, T.; Eisenbeiss, T.; Hohle, M. M.; Va?ko, M.; Ginski, C.; Rammo, W.; Moualla, M.; Broeg, C.

2009-05-01

308

Photometric properties and origin of bulges in SB0 galaxies  

NASA Astrophysics Data System (ADS)

We have derived the photometric parameters for the structural components of a sample of fourteen SB0 galaxies by applying a parametric photometric decomposition to their observed I-band surface brightness distribution. We find that SB0 bulges are similar to bulges of the early-type unbarred spirals, i.e. they have nearly exponential surface brightness profiles (< n>=1.48±0.16) and their effective radii are strongly coupled to the scale lengths of their surrounding discs (< r_e/h>=0.20±0.01). The photometric analysis alone does not allow us to differentiate SB0 bulges from unbarred S0 ones. However, three sample bulges have disc properties typical of pseudobulges. The bulges of NGC 1308 and NGC 4340 rotate faster than bulges of unbarred galaxies and models of isotropic oblate spheroids with equal ellipticity. The bulge of IC 874 has a velocity dispersion lower than expected from the Faber-Jackson correlation and the fundamental plane of the elliptical galaxies and S0 bulges. The remaining sample bulges are classical bulges, and are kinematically similar to lower-luminosity ellipticals. In particular, they follow the Faber-Jackson correlation, lie on the fundamental plane and those for which stellar kinematics are available rotate as fast as the bulges of unbarred galaxies.

Aguerri, J. A. L.; Elias-Rosa, N.; Corsini, E. M.; Muñoz-Tuñón, C.

2005-04-01

309

Photometric Observations of Transiting Planet Candidates With a Small Telescope  

NASA Astrophysics Data System (ADS)

We are part of a ground based team that looks for transiting planets. Our collaborators' telescopes gather photometric data on thousands of stars each night, searching for any which show the small dip in brightness that may be indicative of a planet passing in front of the star. When such a candidate has been identified, it is put into a schedule for further photometric and radial velocity observations. We take follow-up photometric data with the 16-inch David Derrick telescope at the Orson Pratt Observatory at Brigham Young University (BYU). As the predicted drops in magnitude caused by transiting planets are often quite small, we have to determine the limits of this telescope - to see if it is sensitive enough to detect such minute changes in brightness or if there is enough inherent error to hide the transit. We present follow-up data taken with our telescope on several of the team's transiting planet candidates along with observations of known transiting planets to demonstrate the telescope's capabilities. We show the errors in photometry of our target objects and also include plots of stable ensemble stars to exhibit the level of variability that we see from imperfections in images and observing conditions. This research was funded in part by the Physics and Astronomy REU program at Brigham Young University during the summer of 2013.

Stoker, Emily; Stephens, D.; Lara, P.; Ranquist, E.

2013-10-01

310

Calibration of LSST Instrumental and Atmospheric Photometric Passbands  

SciTech Connect

The Large Synoptic Survey Telescope (LSST) will continuously image the entire sky visible from Cerro Pachon in northern Chile every 3-4 nights throughout the year. The LSST will provide data for a broad range of science investigations that require better than 1% photometric precision across the sky (repeatability and uniformity) and a similar accuracy of measured broadband color. The fast and persistent cadence of the LSST survey will significantly improve the temporal sampling rate with which celestial events and motions are tracked. To achieve these goals, and to optimally utilize the observing calendar, it will be necessary to obtain excellent photometric calibration of data taken over a wide range of observing conditions - even those not normally considered 'photometric'. To achieve this it will be necessary to routinely and accurately measure the full optical passband that includes the atmosphere as well as the instrumental telescope and camera system. The LSST mountain facility will include a new monochromatic dome illumination projector system to measure the detailed wavelength dependence of the instrumental passband for each channel in the system. The facility will also include an auxiliary spectroscopic telescope dedicated to measurement of atmospheric transparency at all locations in the sky during LSST observing. In this paper, we describe these systems and present laboratory and observational data that illustrate their performance.

Burke, David L.; /SLAC; Axelrod, T.; /Arizona U., Astron. Dept. - Steward Observ.; Barrau, Aurelien; Baumont, Sylvain; /LPSC, Grenoble; Blondin, Stephane; /Marseille, CPPM; Claver, Chuck; /NOAO, Tucson; Gorecki, Alexia; /LPSC, Grenoble; Ivezic, Zeljko; Jones, Lynne; /Washington U., Seattle, Astron. Dept.; Krabbendam, Victor; Liang, Ming; Saha, Abhijit; /NOAO, Tucson; Smith, Allyn; /Austin Peay State U.; Smith, R.Chris; /Cerro-Tololo InterAmerican Obs.; Stubbs, Christopher W.; /Harvard-Smithsonian Ctr. Astrophys.

2011-07-06

311

Measuring redshift-space distortions using photometric surveys  

NASA Astrophysics Data System (ADS)

We outline how redshift-space distortions (RSD) can be measured from the angular correlation function, w(?), of galaxies selected from photometric surveys. The natural degeneracy between RSD and galaxy bias can be minimized by comparing results from bins with top-hat galaxy selection in redshift, and bins based on the radial position of galaxy pair centres. This comparison can also be used to test the accuracy of the photometric redshifts. The presence of RSD will be clearly detectable with the next generation of photometric redshift surveys. We show that the Dark Energy Survey (DES) will be able to measure f(z)?8(z) to a 1? accuracy of (17 ×b) per cent, using galaxies drawn from a single narrow redshift slice centred at z= 1. Here b is the linear bias, and f is the logarithmic rate of change of the linear growth rate with respect to the scalefactor. Extending to measurements of w(?) for a series of bins of width 0.02(1 +z) over 0.5 < z < 1.4 will measure ? to a 1? accuracy of 0.25, given the model f=?m(z)?, and assuming a linear bias model that evolves such that b= 0.5 +z (and fixing other cosmological parameters). The accuracy of our analytic predictions is confirmed using mock catalogues drawn from simulations conducted by the Marenostrum Institut de Ciències de l'Espai Simulations (MICE) collaboration.

Ross, Ashley J.; Percival, Will J.; Crocce, Martín; Cabré, Anna; Gaztañaga, Enrique

2011-08-01

312

[Estimation of the concentration of urea in the blood of horses, cattle, goats and dogs using the "Merckognost Harnstoff" method compared with an enzymatic, photometric method (author's transl)].  

PubMed

To examine the suitability and reliability in field use of the "Merckognost Harnstoff" method in estimating the concentration of urea in the blood of horses, cattle, goats and dogs, the levels determined by this procedure were compared with those determined by an enzymatic (urease) photometric method widely used in laboratories. It was concluded from the results obtained that estimation using the "Merckognost Harnstoff" is sufficiently reliable for the rapid assay of urea in the blood under field conditions. PMID:1198574

Schotman, A J; Wensing, T; Ockels, J; de Bruyne, J J; Hendriks, H J

1975-11-01

313

Exact Analysis of Competition Ligand Binding by Displacement Isothermal Titration Calorimetry  

Microsoft Academic Search

A rigorous method for the least-squares nonlinear regression analysis of displacement isothermal titration calorimetric data is presented. The method can fit the binding isotherm of a ligand which is competitively inhibited in its binding by another bound ligand to a molecule with n identical and independent binding sites. There are no other assumptions for the method and no approximations. Analysis

Bent W. Sigurskjold

2000-01-01

314

Hydrogen-ion titrations of amino acids and proteins in solutions containing concentrated electrolyte.  

National Technical Information Service (NTIS)

This report describes a first attempt to quantify the net charge as a function of solution pH for lysozyme and (alpha)-chymotrypsin at 0.1 M, 1.0 M and 3.0 M ionic strength, (IS). The calculations are based on the residue (titratable group) pK(sub a)'s in...

F. Fergg D. E. Kuehner H. W. Blanch J. M. Prausnitz

1994-01-01

315

Trace analysis of acids and bases by conductometric titration with multiparametric non-linear regression.  

PubMed

A chemometric method for analysis of conductometric titration data was introduced to extend its applicability to lower concentrations and more complex acid-base systems. Auxiliary pH measurements were made during the titration to assist the calculation of the distribution of protonable species on base of known or guessed equilibrium constants. Conductivity values of each ionized or ionizable species possibly present in the sample were introduced in a general equation where the only unknown parameters were the total concentrations of (conjugated) bases and of strong electrolytes not involved in acid-base equilibria. All these concentrations were adjusted by a multiparametric nonlinear regression (NLR) method, based on the Levenberg-Marquardt algorithm. This first conductometric titration method with NLR analysis (CT-NLR) was successfully applied to simulated conductometric titration data and to synthetic samples with multiple components at concentrations as low as those found in rainwater (approximately 10 micromol L(-1)). It was possible to resolve and quantify mixtures containing a strong acid, formic acid, acetic acid, ammonium ion, bicarbonate and inert electrolyte with accuracy of 5% or better. PMID:18970555

Coelho, Lúcia H G; Gutz, Ivano G R

2006-03-15

316

Performing Titration Analyses for Water Quality. Module 17. Vocational Education Training in Environmental Health Sciences.  

ERIC Educational Resources Information Center

This module, one of 25 on vocational education training for careers in environmental health occupations, contains self-instructional materials on performing titration analysis for water quality. Following guidelines for students and instructors and an introduction that explains what the student will learn are three lessons: (1) naming each part of…

Consumer Dynamics Inc., Rockville, MD.

317

Titration of a Solid Acid Monitored by X-Ray Diffraction  

ERIC Educational Resources Information Center

An experiment is described to introduce students to an important class of solid-state reactions while reinforcing concepts of titration by using a pH meter and a powder X-ray diffractometer. The experiment was successful in teaching students the abstract concepts of solid-state structure and diffraction by applying the diffraction concepts learned…

Dungey, Keenan E.; Epstein, Paul

2007-01-01

318

Use of tetrabutylammonium tribromide for voltametric titration of unsaturation in vegetable oils and fatty acids  

Microsoft Academic Search

The use of tetrabutylammonium tribromide as reagent for bromination of carbon-carbon double bonds of fatty acids and vegetable\\u000a oils, followed by a voltametric titration of tribromide and bromide ions, has been studied. This method is easy and fast,\\u000a and results show good accuracy and high sensitivity.

J. Berthelota; P. L. Desbène; A. Desbène-Monvernay

1993-01-01

319

DETERMINATION OF LITHIUM AND SODIUM CHLORIDES BY POTENTIOMETRIC TITRATION FOLLOWING 2ETHYL1HEXANOL SEPARATION  

Microsoft Academic Search

Sodium and lithium chlorides are titrated potentiometrically with silver ; nitrate following two extractions of the lithium chloride with 2-ethyl-1-hexanol. ; Using glass and silver- silver chloride electrodes, the detection of the end ; point is enhanced in the organic medium. For 17 determinations, an average of ; 99.99% was obtained for lithium, with a standard deviation of 0.16%, and

G. R. Waterbury; E. H. Van Kooten; Bruno Morosin

1958-01-01

320

Impairment and Deportment Responses to Different Methylphenidate Doses in Children With ADHD: The MTA Titration Trial  

Microsoft Academic Search

ObjectiveResults of the NIMH Collaborative Multisite Multimodal Treatment Study of Children With Attention-Deficit\\/Hyperactivity Disorder (MTA) were analyzed to determine whether a double-blind, placebo-controlled methylphenidate (MPH) titration trial identified the best MPH dose for each child with attention-deficit\\/hyperactivity disorder (ADHD).

LAURENCE L. GREENHILL; JAMES M. SWANSON; BENEDETTO VITIELLO; MARK DAVIES; WALTER CLEVENGER; MIN WU; L. EUGENE ARNOLD; HOWARD B. ABIKOFF; OSCAR G. BUKSTEIN; C. KEITH CONNERS; GLEN R. ELLIOTT; LILY HECHTMAN; STEPHEN P. HINSHAW; BETSY HOZA; PETER S. JENSEN; HELENA C. KRAEMER; JOHN S. MARCH; JEFFREY H. NEWCORN; JOANNE B. SEVERE; KAREN WELLS; TIMOTHY WIGAL

2001-01-01

321

Prednisone for chronic active liver disease: dose titration, standard dose, and combination with azathioprine compared  

Microsoft Academic Search

Among 120 consecutive patients with chronic active liver disease (CALD) randomized to different treatments, those receiving maintenance doses of prednisone 20 mg daily (Pred), prednisone in doses given on alternate days and titrated to secure resolution of clinical and biochemical abnormalities (Pred-Titrad), or a combination of prednisone 10 mg and azathioprine 50 mg daily (Comb) survived and underwent resolution of

W H Summerskill; M G Korman; H V Ammon; A H Baggenstoss

1975-01-01

322

Charge Density Quantification of Polyelectrolyte Polysaccharides by Conductometric Titration: An Analytical Chemistry Experiment  

ERIC Educational Resources Information Center

An easy analytical method for determination of the charge density of polyelectrolytes, including polysaccharides and other biopolymers, is presented. The basic principles of conductometric titration, which is used in the pulp and paper industry as well as in colloid and interface science, were adapted to quantify the charge densities of a…

Farris, Stefano; Mora, Luigi; Capretti, Giorgio; Piergiovanni, Luciano

2012-01-01

323

Thermodynamic analysis of Bacillus subtilis endospore protonation using isothermal titration calorimetry  

NASA Astrophysics Data System (ADS)

Bacterial proton and metal adsorption reactions have the capacity to affect metal speciation and transport in aqueous environments. We coupled potentiometric titration and isothermal titration calorimetry (ITC) analyses to study Bacillus subtilis spore-proton adsorption. We modeled the potentiometric data using a four and five-site non-electrostatic surface complexation model (NE-SCM). Heats of spore surface protonation from coupled ITC analyses were used to determine site specific enthalpies of protonation based on NE-SCMs. The five-site model resulted in a substantially better model fit for the heats of protonation but did not significantly improve the potentiometric titration model fit. The improvement observed in the five-site protonation heat model suggests the presence of a highly exothermic protonation reaction circa pH 7 that cannot be resolved in the less sensitive potentiometric data. From the log Ks and enthalpies we calculated corresponding site specific entropies. Log Ks and site concentrations describing spore surface protonation are statistically equivalent to B. subtilis cell surface protonation constants. Spore surface protonation enthalpies, however, are more exothermic relative to cell based adsorption suggesting a different bonding environment. The thermodynamic parameters defined in this study provide insight on molecular scale spore-surface protonation reactions. Coupled ITC and potentiometric titrations can reveal highly exothermic, and possibly endothermic, adsorption reactions that are overshadowed in potentiometric models alone. Spore-proton adsorption NE-SCMs derived in this study provide a framework for future metal adsorption studies.

Harrold, Zoë R.; Gorman-Lewis, Drew

2013-05-01

324

Surface characterization of plasma sprayed oxide materials: estimation of surface acidity using mass titration.  

PubMed

The aim of this study was to characterize the influence of plasma spraying on the point of zero charge (PZC) of Al2O3-, Cr2O3- and TiO2-based materials. PZC is one of the most important parameter, which describes the acidity of oxide material in aqueous environments. PZC values of several plasma sprayed oxides were determined using mass titration method. Studies were performed for initial spray powders and plasma sprayed coating materials. In addition, mass titration experiments were performed for water-washed and nonwashed samples. It was found that mass titration is a suitable method to estimate the surface acidity of relatively coarse sample powders. It was found for most of the studied materials that the limiting pH values (assumed to be close PZC) were close to those reported in literature for the PZC values of traditionally manufactured oxide materials. On the other hand, mass titration curves of some oxide samples showed unexpected deviation in curve shapes and limiting pH. These deviations were probably due to selective dissolution of sample contaminations or sample material. PMID:15271562

Harju, Mika; Levänen, Erkki; Mäntylä, Tapio

2004-08-15

325

DETERMINATION OF CONDITIONAL STABILITY CONSTANTS OF METAL-Trichoderma viride COMPLEXES BY THE POTENTIOMETRIC TITRATION METHOD  

Microsoft Academic Search

SUMMARY In this paper the binding ability of functional groups present in the cell walls of an ubiquitous soil fungus, Trichoderma viride Pers.: Fr., towards some divalent heavy metals, Cd, Co, Cu, Pb and Zn, was studied. Proc- essing the data from potentiometric titrations of T. viride by the McCallum, Midgley and Gran's combined meth- ods, the surface of the

Giovanna SANNA; Guido ALBERTI; Paola CASTALDI; Pietro MELIS

326

Base-Induced 2,4,6-Trinitrotoluene Transformation, Titration Studies.  

National Technical Information Service (NTIS)

The removal of 2,4,6-trinitrotoluene (TNT) from solution by the addition of a base, sodium hydroxide (NaOH), was examined. TNT solutions were titrated to determine the required hydroxide concentration for the removal of TNT from solutions to proceed. It w...

L. D. Hansen D. D. Ringelberg D. R. Felt J. D. Davis

2001-01-01

327

Solubility measurement of polymorphic compounds via the pH-metric titration technique.  

PubMed

In drug development, the thermodynamically most stable form of a compound is preferred because metastable forms are prone to transform to the stable form during processing, formulation, or storage [Guillory, J.K., 1999. Generation of polymorphs, hydrates, solvates, and amorphous solids. In: Brittain, H.G. (Ed.), Polymorphism in Pharmaceutical Solids. Marcel Dekker, New York, pp. 183-226]. It is therefore important to discover and characterize the stable form as early as possible. One of the most important properties to determine is thermodynamic solubility. However, due to compound and time constraints this solubility value is usually not determined until late in discovery. This report explores the ability of the pH-metric titration method to measure intrinsic solubility of the stable form of compounds that exist in one or more polymorphic forms. One metastable form and the stable form of eight compounds were examined. Intrinsic solubility was measured via pH-metric titration. The technique was performed on a larger scale in order to monitor polymorphic form changes by powder X-ray diffraction. Shake-flask solubility and corresponding X-ray diffraction data of each form was also determined. The results of this study indicate that, in general, when starting with a metastable polymorph, the pH-metric titration method is able to achieve the solubility of the stable form by the third titration, while the traditional shake-flask solubility method is unable to consistently determine the stable form solubility. PMID:17049191

Fioritto, Ann F; Bhattachar, Shobha N; Wesley, James A

2007-02-01

328

Complexometric Titrations: Competition of Complexing Agents in the Determination of Water Hardness with EDTA  

Microsoft Academic Search

The competition of complexing agents for the same metal ion and the formation of colored metal-ion complexes is demonstrated with the use of an overhead projector. This demonstration can be used to emphasize both the relevance of the relative values of formation constants in the complexation of metal cations and the applicability of complexometric titrations in quantitative chemical analysis. The

M. Cecilia Yappert; Donald B. Dupre

1997-01-01

329

COMPLEXOMETRIC TITRATION OF YTTRIUM AND THE LANTHANONS. I. A COMPARISON OF DIRECT METHODS  

Microsoft Academic Search

A comparison was made of a number of direct complexometric titrations ; previously published ior the determination of yttrium and the lanthanons. ; Working and optimum pH ranges were obtained for what are considered to be the ; best indicators, Alizarin Red S screened with Methylene Blue, Eriochrome Black T, ; Copper-Naphthyl Azoxine, and Xylenol Orange. The precision and accuracy

S. J. Lyle

1963-01-01

330

Intravenous Nefopam Reduces Postherpetic Neuralgia during the Titration of Oral Medications  

PubMed Central

Background The recently known analgesic action mechanisms of nefopam (NFP) are similar to those of anticonvulsants and antidepressants in neuropathic pain treatment. It is difficult to prescribe high doses of oral neuropathic drugs without titration due to adverse effects. Unfortunately, there are few available intravenous analgesics for the immediate management of acute flare-ups of the chronic neuropathic pain. The aim of this study was to determine the additional analgesic effects for neuropathic pain of NFP and its adverse effects during the titration of oral medications for neuropathic pain among inpatients with postherpetic neuralgia (PHN). Methods Eighty inpatients with PHN were randomly divided into either the NFP or normal saline (NS) groups. Each patient received a 3-day intravenous continuous infusion of either NFP with a consecutive dose reduction of 60, 40, and 20 mg/d, or NS simultaneously while dose titrations of oral medications for neuropathic pain gradually increased every 3 days. The efficacy of additional NFP was evaluated by using the neuropathic pain symptom inventory (NPSI) score for 12 days. Adverse effects were also recorded. Results The median NPSI score was significantly lower in the NFP group from days 1 to 6 of hospitalization. The representative alleviating symptoms of pain after using NFP were both spontaneous and evoked neuropathic pain. Reported common adverse effects were nausea, dizziness, and somnolence, in order of frequency. Conclusions An intravenous continuous infusion of NFP reduces spontaneous and evoked neuropathic pain with tolerable adverse effects during the titration of oral medications in inpatients with PHN.

Joo, Young Chan; Ko, Eun Sung; Cho, Jae Geun; Ok, Young Min; Jung, Gyu Yong

2014-01-01

331

DETERMINATION OF URANYL NITRATE IN FREE NITRIC ACID BY MEANS OF ACIDIMETRIC TITRATION  

Microsoft Academic Search

A method based on the quantitative reaction of uranyl nitrate with ; hydrogen peroxide to release nitric acid is presented for the determination of ; uranyl nitrate in nitric acid solution. The hydrogen peroxide is added to the ; uranyl nitrate solution and the total nitric acid determined by visual or ; potentiometric titration with sodium hydroxide. The free nitric

J. Cepelak; Maly; V. J. f Vesely

1959-01-01

332

Photodigitizing procedures  

NASA Astrophysics Data System (ADS)

This report documents procedures and programs for efficiently running the Photo Digitizing System at the Naval Biodynamics Laboratory. Procedures have been tested and have been found to be effective. Any future acquisitions of programs or changes to current programs should be incorporated in these procedures. On-going research programs use high speed instrumentation cameras to record the motion of test subjects during biodynamic experiments. The films are digitized and the 3-dimensional motion is reconstructed and analyzed. Experimental research is performed to determine the effects of aircraft crashes, ship motion, vibration, aircraft ejection and parachute opening forces on the health and performance of Navy personnel.

Kilgore, P. D.; Gottbrath, J. H.

1984-02-01

333

Cosmetic Procedures  

MedlinePLUS

... 11.14 Read More Find a Cosmetic Dentist Teeth Whitening Accredited and General Member Dental Patients ? Cosmetic Procedures ... offered by your dentist’s use of modern technology. Teeth Whitening Most teeth can be whitened (some call it ...

334

Acid-base titration across the membrane system of rat-liver mitochondria  

PubMed Central

1. Pulsed acid–base titrations of suspensions of rat-liver mitochondria under anaerobic equilibrium conditions show fast and slow titration processes. 2. The fast process is the titration of the outer aqueous phase of the mitochondria, which is continuous with the suspension medium, and the slow process can be identified with the titration of the inner aqueous phase of the mitochondria, which is separated from the outer aqueous phase by the non-aqueous osmotic barrier or M phase of the cristae membrane system. 3. The buffering power of the outer and inner phases have been separately measured over a range of pH values. 4. The rate of titration of the inner aqueous phase under a known protonmotive force across the M phase has been characterized by an effective proton conductance coefficient, which, near pH7 and at 25°, is only 0·45?mho/cm.2 of the M-phase membrane. 5. The low effective proton conductance of the M phase will account quantitatively for the observed respiratory control in state 4, assuming that oxidoreduction and phosphorylation are coupled by a circulating proton current as required by the chemi-osmotic hypothesis. 6. The addition of 2,4-dinitrophenol (or carbonyl cyanide p-trifluoromethoxyphenylhydrazone) at normal uncoupling concentrations causes a large increase in the effective proton conductance of the M phase of the cristae membrane. 7. The increase of the effective proton conductance of the M phase by 2,4-dinitrophenol (or carbonyl cyanide p-trifluoromethoxyphenylhydrazone) will account quantitatively for the short-circuiting effect of the uncoupling agent on the proton current and for the observed rise of the rate of respiration to that characteristic of state 3 or higher.

Mitchell, Peter; Moyle, Jennifer

1967-01-01

335

On-line titration method for monitoring buffer capacity and total volatile fatty acid levels in anaerobic digesters.  

PubMed

The construction and use of an automatic on-line titration unit for routine or event- initiated monitoring of alkalinity, buffer capacity, and volatile fatty acid (VFA) levels is presented. Under computer control a sample of digester liquor is pumped into the titration vessel and weighed. A sequence of titration, sparging, and back-titration operations are then initiated during which the pH and weight are recorded continuously and a titration curve constructed. From the curve, estimates of the alkalinity, buffer capacity to any desired pH endpoint, and total VFA levels are computed. The data is stored to disk and output as hard copy together with the titration curve itself. Monitoring and control of the titration apparatus is effected by a microcomputer via two analog input lines and eight digital output lines, respectively. The system is suitable for downloading to a small, inexpensive dedicated microprocessor-based system. The apparatus is constructed from standard and widely available equipment and the titration sequence, being under software control, is fully adaptable to particular requirements. The use of this facility in the on-line monitoring, control and optimization of the anaerobic digestion process is discussed. PMID:18587953

Powell, G E; Archer, D B

1989-01-25

336

The Quantitative Resolution of a Mixture of Group II Metal Ions by Thermometric Titration with EDTA. An Analytical Chemistry Experiment.  

ERIC Educational Resources Information Center

Presents an experiment in thermometric titration used in an analytic chemistry-chemical instrumentation course, consisting of two titrations, one a mixture of calcium and magnesium, the other of calcium, magnesium, and barium ions. Provides equipment and solutions list/specifications, graphs, and discussion of results. (JM)

Smith, Robert L.; Popham, Ronald E.

1983-01-01

337

Several Applications of Advanced Scientific Calculators: Nonlinear Least-Squares Analysis and Titration of a Weak Acid  

Microsoft Academic Search

Several advanced applications of scientific graphing calculators are demonstrated. These include (a) nonlinear least squares analysis and (b) construction of titration curves for weak acids with a strong base. Stepwise instructions for obtaining the titration curves with TI-80 Series Calculators are presented. Immediate display of graphical results of a solution from a quantitative chemical problem in a classroom setting is

Myung-Hoon Kim; Suw-Young Ly; Tae-Kee Hong

2002-01-01

338

Photometric determination of sulfuric acid in ammonium sulfate  

SciTech Connect

A method of determining the concentration of sulfuric acid in ammonium sulfate was outlined. Due to the unfavorable effects sulfuric acid has in fertilizers, Soviet industry limits the concentration to 0.025-0.050 wt. % H/sub 2/SO/sub 4/ in ammonium sulfate. The method developed by the authors was based on the optical density of an acid-base indicator in the presence of an acid. The indicator used in the experiments was 2,5-dinitrophenol. The accuracy of this method compared favorably to the more commonly used titration method. (JMT)

Yakovleva, T.P.; Privalova, N.V.; Tsebrii, L.S.; Vail, E.I.

1982-01-01

339

Detection of HLA antibodies by an enzyme-linked photometric immune phagocytosis inhibition test.  

PubMed

The immune phagocytosis inhibition test (IPI) has been described as a sensitive method for the detection of cytotoxic and non-cytotoxic HLA antibodies. We performed a photometric IPI and compared this technique with the conventional microscopic IPI. In further investigations we used the photometric IPI in comparison with the lymphocytotoxicity test (LCT) for the detection of HLA antibodies. The photometric IPI showed a high correlation to the microscopic IPI. In tests with different known HLA antibodies the photometric IPI reached a sensitivity of 85.1% versus 80.5% in the LCT, and a specificity of 92.3 versus 100% in the LCT. Diluted patient sera showed a higher sensitivity in the photometric IPI. We conclude that the photometric IPI can be used as a convenient and sensitive technique for the detection of HLA antibodies. PMID:9422114

Cassens, U; Benn, H P; Dittmer, R; Dominka, T; Lüdemann, K; Kühnl, P

1994-01-01

340

Probable swirls detected as photometric anomalies in Oceanus Procellarum  

NASA Astrophysics Data System (ADS)

Images of the lunar nearside obtained by telescopes of Maidanak Observatory (Uzbekistan) and Simeiz Observatory (Crimea, Ukraine) equipped with Canon CMOS cameras and Sony CCD LineScan camera were used to study photometric properties of the lunar nearside in several spectral bands. A wide range of lunar phase angles was covered, and the method of phase ratios to assess the steepness of the phase function at different phase angles is applied. We found several areas with photometric anomalies in the south-west portion of the lunar disk that we refer to as Oceanus Procellarum anomalies. The areas being unique on the lunar nearside do not obey the inverse correlation between albedo and phase-curve slope, demonstrating high phase-curve slopes at intermediate albedo. Low-Sun images acquired with Lunar Orbiter IV and Apollo-16 cameras do not reveal anomalous topography of the regions, at least for scales larger than several tens of meters. The areas also do not have any thermal inertia, radar (70 and 3.8 cm), magnetic, or chemical/mineral peculiarities. On the other hand they exhibit a polarimetric signature that we interpret to be due to the presence of a porous regolith upper layer consisting of dust particles. The anomalies may be interpreted as regions of very fresh shallow regolith disturbances caused by impacts of meteoroid swarms consisting of rather small impactors. This origin is similar to one of the hypotheses for the origin of lunar swirls like the Reiner-? formation. The photometric difference between the shallow and pervasive (Reiner-? class) swirls is that the latter appear to have a significant amount of immature soils in the upper surface layers.

Shkuratov, Yu.; Kaydash, V.; Gerasimenko, S.; Opanasenko, N.; Velikodsky, Yu.; Korokhin, V.; Videen, G.; Pieters, C.

2010-07-01

341

COSMOLOGY WITH PHOTOMETRIC SURVEYS OF TYPE Ia SUPERNOVAE  

SciTech Connect

We discuss the extent to which photometric measurements alone can be used to identify Type Ia supernovae (SNIa) and to determine the redshift and other parameters of interest for cosmological studies. We fit the light curve data of the type expected from a survey such as the one planned with the Large Synoptic Survey Telescope (LSST) and also remove the contamination from the core-collapse SNe to SNIa samples. We generate 1000 SNIa mock flux data for each of the LSST filters based on existing design parameters, then use a Markov Chain Monte Carlo analysis to fit the redshift, apparent magnitude, stretch factor, and the phase of the SNIa. We find that the model fitting works adequately well when the true SNe redshift is below 0.5, while at z < 0.2 the accuracy of the photometric data is almost comparable with spectroscopic measurements of the same sample. We discuss the contamination of Type Ib/c (SNIb/c) and Type II supernova (SNII) on the SNIa data set. We find that it is easy to distinguish the SNII through the large chi{sup 2} mismatch when fitting to photometric data with Ia light curves. This is not the case for SNIb/c. We implement a statistical method based on the Bayesian estimation in order to statistically reduce the contamination from SNIb/c for cosmological parameter measurements from the whole SNe sample. The proposed statistical method also evaluates the fraction of the SNIa in the total SNe data set, which provides a valuable guide to establish the degree of contamination.

Gong Yan; Cooray, Asantha [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Chen Xuelei [National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 100012 (China)

2010-02-01

342

A photometric approach to detecting earth-sized planets  

NASA Technical Reports Server (NTRS)

The photometric method for searching for planets around stars depends on the observation of the decrease in light flux produced by the transit of a planet across the stellar disk. It is shown that a three-year observation period should permit meaningful statements to be made about the frequency of solar-type planetary systems. A state-of-the-art photometer is being developed to test components and concepts. The goal is the development of a photometer that can routinely measure the relative brightness of stars to a precision of 1 part in 100,000.

Borucki, W. J.; Allen, L. E.; Taylor, W. S.; Young, A. T.; Schaefer, A. R.

1988-01-01

343

Characterizing the Photometric Response of the ANS Collaboration Monitoring Program  

NASA Astrophysics Data System (ADS)

The ANS Collaboration uses the UBVR CI C filters from various commercial manufacturers (Omega Optical, Custom Scientific, Schuler, Optec, Astrodon) for its ongoing photometric monitoring of symbiotic stars. We measured their transmittance profiles over the range 2000 Å to 1.1 ? m for various operating conditions, and we are monitoring their evolution over time. Their field performance in terms of color equations has been evaluated by analyzing the transformations from local to standard system of the 14602 observing runs so far collected on symbiotic stars with the ANS Collaboration telescopes. Ageing effects, red leaks and transmittance vs. angle of incidence are also evaluated.

Munari, U.; Moretti, S.

344

Kernel PCA for Type Ia supernovae photometric classification  

NASA Astrophysics Data System (ADS)

The problem of supernova photometric identification will be extremely important for large surveys in the next decade. In this work, we propose the use of kernel principal component analysis (KPCA) combined with k = 1 nearest neighbour algorithm (1NN) as a framework for supernovae (SNe) photometric classification. The method does not rely on information about redshift or local environmental variables, so it is less sensitive to bias than its template fitting counterparts. The classification is entirely based on information within the spectroscopic confirmed sample and each new light curve is classified one at a time. This allows us to update the principal component (PC) parameter space if a new spectroscopic light curve is available while also avoids the need of re-determining it for each individual new classification. We applied the method to different instances of the Supernova Photometric Classification Challenge (SNPCC) data set. Our method provides good purity results in all data sample analysed, when signal-to-noise ratio (SNR) ? 5. Therefore, we can state that if a sample as the post-SNPCC was available today, we would be able to classify ?15 per cent of the initial data set with purity ?90 per cent (D7+SNR3). Results from the original SNPCC sample, reported as a function of redshift, show that our method provides high purity (up to ?97 per cent), especially in the range of 0.2 ? z < 0.4, when compared to results from the SNPCC, while maintaining a moderate figure of merit (?0.25). This makes our algorithm ideal for a first approach to an unlabelled data set or to be used as a complement in increasing the training sample for other algorithms. We also present results for SNe photometric classification using only pre-maximum epochs, obtaining 63 per cent purity and 77 per cent successful classification rates (SNR ? 5). In a tougher scenario, considering only SNe with MLCS2k2 fit probability >0.1, we demonstrate that KPCA+1NN is able to improve the classification results up to >95 per cent (SNR ? 3) purity without the need of redshift information. Results are sensitive to the information contained in each light curve, as a consequence, higher quality data points lead to higher successful classification rates. The method is flexible enough to be applied to other astrophysical transients, as long as a training and a test sample are provided.

Ishida, E. E. O.; de Souza, R. S.

2013-03-01

345

KINEMATIC AND PHOTOMETRIC EVIDENCE FOR A BAR IN NGC 2683  

SciTech Connect

We present optical long-slit and SparsePak Integral Field Unit emission line spectroscopy along with optical broadband and near-IR images of the edge-on spiral galaxy NGC 2683. We find a multi-valued, figure-of-eight velocity structure in the inner 45'' of the long-slit spectrum and twisted isovelocity contours in the velocity field. We also find, regardless of wavelength, that the galaxy isophotes are boxy. We argue that taken together, these kinematic and photometric features are evidence for the presence of a bar in NGC 2683. We use our data to constrain the orientation and strength of the bar.

Kuzio de Naray, Rachel [Center for Cosmology, Department of Physics and Astronomy, University of California, Irvine, CA 92697-4575 (United States); Zagursky, Matthew J.; McGaugh, Stacy S. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States)], E-mail: kuzio@uci.edu, E-mail: mzagursk@umd.edu, E-mail: ssm@astro.umd.edu

2009-10-15

346

Probing dark energy with lensing magnification in photometric surveys.  

PubMed

I present an estimator for the angular cross correlation of two tracers of the cosmological large-scale structure that utilizes redshift information to isolate separate physical contributions. The estimator is derived by solving the Limber equation for a reweighting of the foreground tracer that nulls either clustering or lensing contributions to the cross correlation function. Applied to future photometric surveys, the estimator can enhance the measurement of gravitational lensing magnification effects to provide a competitive independent constraint on the dark energy equation of state. PMID:24580685

Schneider, Michael D

2014-02-14

347

A photometric function for diffuse reflection by particulate materials  

NASA Technical Reports Server (NTRS)

A photometric function is proposed to describe the diffuse reflection of radiation by particulate materials. Both multiple scattering and the dominant effects of particle shadowing are included and the function is verified by comparisons with the photometries of laboratory surfaces. Brightness measurements of planetary and other diffusely scattering surfaces can be used to calculate the brightness for geometries other than those used in the measurements and for which the Minnaert function does not apply. The measurements also can be directly related to such surface characteristics as particle size, single-particle albedo, and compactness.

Meador, W. E.; Weaver, W. R.

1975-01-01

348

Tracing the sound horizon scale with photometric redshift surveys  

NASA Astrophysics Data System (ADS)

We propose a novel method for the extraction of the baryonic acoustic oscillation scale in galaxy photometric surveys. The evolution of this scale can be used as a standard ruler in order to constrain cosmological parameters. The method consists in parametrize the angular correlation function ?(?), with a simple analitical expresion, in order to extract the sound horizon scale. The method has been tested in the MICE simulation, one of the largest N-body simulation to date. We have considered projection effects, non-linearities and observational effects in our analysis, obtaining errors in cosmological parameters in agreement with what is expected in new generation surveys.

Carnero-Rosell, A.; Sánchez, E.; García-Bellido, J.; Gaztañaga, E.; de Simoni, F.; Crocce, M.; Cabré, A.; Fosalba, P.; Alonso, D.

2011-11-01

349

Photometric investigation of the Herbig Ae/Be star MWC 297. I. Quasisimultaneous UBVRIJHK observations  

SciTech Connect

In order to make a statistical investigation of the photometric variability of the young star MWC 297 a number of quasisimultaneous observations in the photometric bands UBVRIJHK has been made. The coefficients of the correlation between the variations of the brightness in the different photometric bands have been determined by the proposed method. An anticorrelation between the variations in the bands U and K has been found. A possible mechanisms of the irregular variability of the star is proposed.

Bergner, Yu.K.; Kozlov, V.P.; Krivtsov, A.A.; Miroshnichenko, A.S.; Yudin, R.V.; Yutanov, N.Yu.; Dzhakusheva, K.G.; Kuratov, K.S.; Mukanov, D.B.

1988-11-01

350

Documentation for the machine-readable version of photometric data for nearby stars  

NASA Technical Reports Server (NTRS)

A computer list of all photometric systems (of those considered), in which each star was measured is provided. The file is a subset of a much larger and more comprehensive compilation, which lists all measured photoelectric photometric systems for any star that has been measured in at least one photoelectric system. In addition to the photometric system identifications, cross identifications to the Henry Draper and Durchmusterung catalogs and apparent visual magnitudes are included.

Warren, W. H., Jr.

1982-01-01

351

Air Leak during CPAP Titration as a Risk Factor for Central Apnea  

PubMed Central

Objectives: Emergence of central sleep apnea has been described in the setting of continuous positive airway pressure (CPAP) initiation. The underlying mechanism is unclear; however, we postulate that air leak washing out anatomical dead space is a contributing factor. Design: Data were obtained from 310 patients with obstructive sleep apnea (OSA) who underwent either split-night or full-night CPAP titration during January to July of 2009. The majority (n = 245) underwent titration with a nasal mask. Average total leak and maximum total leak were measured at therapeutic CPAP level. Unintentional leak was calculated by subtracting manufacturer-defined intentional leak from maximum leak. Results: Subjects were divided into two groups: central apnea index (CAI) during titration < 5/hour and ? 5/hour. The groups were similar in terms of gender, age, BMI, and AHI. The CAI < 5 group had a median average leak of 45.5 L/min (IQR 20.8 L/min) versus 51.0 L/min (IQR 21.0 L/min) with CAI ? 5 (p = 0.056). Maximum leak was 59.5 L/min (IQR 27.0 L/min) with CAI < 5 and 75.0 L/min (IQR 27.8 L/min) with CAI ? 5 (p = 0.003). In the subset of subjects titrated using a nasal mask, median average leak was 42.0 L/min (IQR 17.0) in the CAI < 5 group and 50.0 L/min (IQR 16.8) in the CAI ? 5 group (p = 0.001). In the CAI < 5 group, median maximum leak was 57.0 L/min (IQR 23.0) versus 74.5 L/min (IQR 24.3) in the CAI ? 5 group (p < 0.001). Conclusions: Leak during CPAP titration is associated with the development of acute central apnea; these data may have mechanistic and therapeutic implications for complex apnea. Commentary: A commentary on this article appears in this issue on page 1193. Citation: Montesi SB; Bakker JP; Macdonald M; Hueser L; Pittman S; White DP; Malhotra A. Air leak during CPAP titration as a risk factor for central apnea. J Clin Sleep Med 2013;9(11):1187-1191.

Montesi, Sydney B.; Bakker, Jessie P.; Macdonald, Mary; Hueser, Lauren; Pittman, Stephen; White, David P.; Malhotra, Atul

2013-01-01

352

The Determination of the pKaof Multiprotic, Weak Acids by Analyzing Potentiometric Acid Base Titration Data with Difference Plots  

NASA Astrophysics Data System (ADS)

This paper discusses the pKa determination of mono-, di-, and triprotic weak acids with the help of difference (Bjerrum) plots, and the effect of strong acid base concentration errors, ligand weight errors, and nonlinear electrode response. Experimental examples are given for the titration of an acidic heterocycle, as well as glycine, ethylenediamine, and tris(2-aminoethyl)amine (the last two after addition of excess HCl to ensure complete protonation) with standarized NaOH. The analysis procedure makes use of Microsoft Excel spreadsheets and nonlinear least squares curve fitting of the experimental data to the theoretical Bjerrum function. In addition to providing pKa values for mono- and multiprotic acids, this approach has been found suitable for detecting small errors in parameters, such as strong acid and ligand concentration, and corrections can often become necessary to achieve the best fit. Difference plots allow the pKa values of monoprotic and multiprotic weak acids to be determined rapidly and with good precision.

Kraft, Arno

2003-05-01

353

Grievance Procedures.  

ERIC Educational Resources Information Center

Because grievances are unavoidable, it is essential for organizations, such as the schools, to utilize an efficient, effective procedure to handle friction between employers and employees. Through successive steps, representatives of labor and management attempt to resolve the grievance, first with meetings of lower level representatives (such as…

Eisenhower, R. Warren

354

Deinstitutionalization Procedures  

ERIC Educational Resources Information Center

Presented is a step by step procedure for normalizing the life situations of institutionalized handicapped persons by establishing comprehensive community services on a local level. Available from: American Association for the Education of the Severely/Profoundly Handicapped, 1600 West Armory Way, Seattle, Washington 98119. (GW)

Neufeld, G. R.

1977-01-01

355

Mapping extinction using GALEX and SDSS photometric observations  

NASA Astrophysics Data System (ADS)

The primary objective of this work is to create an all sky extinction map of the Milky Way galaxy. We have cross-matched the Sloan Digital Sky Survey (SDSS data release 8) photometric observations with that of Galaxy Evolution Explorer (GALEX data release 6). This provides a wide range of wavelength coverage from Far Ultra-Violet through the optical spectrum and gives one unique SDSS source for every GALEX source. We discuss a sample of ~32000 objects in the north galactic pole (>=75° latitude) from this combined database. The Castelli and Kurucz Atlas was fit to the photometric observations of each star, best fit being determined using a chi-square test. Best fit parameters provide the spectral type and extinction towards each of the objects. The shift in magnitude obtained during the best-fit can be used to determine the distance to each of the stars. With this data, a comprehensive extinction map can be made for the high-latitude objects and later extended to all-sky.

Krishnamoorthy, Preethi; Gudennavar, S. B.; Murthy, Jayant

2013-06-01

356

Far-ultraviolet photometric characteristics of Tethys and Dione  

NASA Astrophysics Data System (ADS)

The icy moons of Saturn orbiting inside the E-ring experience weathering processes: E-ring grains as well as cold plasma ions, neutrals and energetic particles impact their surfaces. The Cassini UVIS instrument (UltraViolet Imaging Spectrograph), operating in the FUV wavelengths (118 - 190nm) probes the uppermost layers of the regolith and is uniquely suited to studying these exogenic processes, leading to a better understanding of the surfaces' evolution and the saturnian environment. We present an analysis of ultraviolet disk-integrated phase curves of Tethys and Dione. We display phase curves for the leading and trailing hemispheres as well as for the Saturn and anti-Saturn ones. As expected, we find that the leading hemisphere is brighter than the trailing and at large phase angles, it seems that we directly observe these E-ring grains in forward scattering. Our data set covers a wide range of phase angles, from 6.8 to 163.9 degrees for Tethys. Our analysis is completed by using a Hapke model to retrieve the photometric parameters of these surfaces, such as the single scattering parameters, the opposition effect parameters (where possible) and information on the roughness. The photometric behavior of Dione is compared and contrasted with that of Tethys, and implications for the exogenic processes affecting the surfaces are discussed.

Royer, E. M.; Hendrix, A. R.

2012-12-01

357

A PHOTOMETRIC METALLICITY ESTIMATE OF THE VIRGO STELLAR OVERDENSITY  

SciTech Connect

We determine photometric metal abundance estimates for individual main-sequence stars in the Virgo Overdensity (VOD), which covers almost 1000 deg{sup 2} on the sky, based on a calibration of the metallicity sensitivity of stellar isochrones in the gri filter passbands using field stars with well-determined spectroscopic metal abundances. Despite the low precision of the method for individual stars, we derive [Fe/H] = -2.0 +- 0.1(internal) +- 0.5(systematic) for the metal abundance of the VOD from photometric measurements of 0.7 million stars in the northern Galactic hemisphere with heliocentric distances from approx10 kpc to approx20 kpc. The metallicity of the VOD is indistinguishable, within DELTA[Fe/H] <= 0.2, from that of field halo stars covering the same distance range. This initial application suggests that the Sloan Digital Sky Survey gri passbands can be used to probe the properties of main-sequence stars beyond approx10 kpc, complementing studies of nearby stars from more metallicity-sensitive color indices that involve the u passband.

An, Deokkeun [Infrared Processing and Analysis Center, California Institute of Technology, Mail Stop 100-22, Pasadena, CA 91125 (United States); Johnson, Jennifer A.; Pinsonneault, Marc H.; Terndrup, Donald M.; Masseron, Thomas [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Beers, Timothy C.; Lee, Young Sun [Department of Physics and Astronomy and JINA (Joint Institute for Nuclear Astrophysics), Michigan State University, E. Lansing, MI 48824 (United States); Delahaye, Franck [Service d'Astrophysique, CEA/DSM/IRFU/SAp, CEA Saclay, 91191 Gif-sur-Yvette Cedex (France); Yanny, Brian, E-mail: deokkeun@ipac.caltech.ed [Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States)

2009-12-10

358

CCD and photon-counting photometric observations of peculiar asteroids  

NASA Astrophysics Data System (ADS)

The photometric observational programme of main-belt asteroids undertaken, since 1980, at the Physics and Astronomy Department of Catania University, mainly by using photoelectric acquisition, has been extended to the Near-Earth Objects, because of the importance of their study to improve the knowledge of the mechanics and the physics of the inner Solar System. The wideness of the observational programme was pursued by using an expressly built CCD camera having a Kodak 4200 detector 2048x2048 pixel class 1, front-illuminated chip with 9 mu m pixel-size, equipped with BVRI Johnson filters. New observations of 4 Vesta, 27 Euterpe, 173 Ino, 182 Elsa, 849 Ara (carried out at M.G. Fracastoro Station of Catania Astrophysical Observatory), 984 Gretia, 3199 Nefertiti and 2004 UE (carried out at Asiago Station of Padova Astronomical Observatory) are presented. The improvement of the rotational period value (for 182 Elsa and 2004 UE it is the first determination), of the lightcurve amplitude and of the B-V colour index was obtained. For 4 Vesta indications on surface mineralogic morphology are deduced from the UBV photometric behaviour while for 182 Elsa, the H-G magnitude relation was carried out.

Fulvio, D.; Blanco, C.; Cigna, M.; Gandolfi, D.

359

WFC3: Improvements to WFC3 UVIS Photometric Calibration  

NASA Astrophysics Data System (ADS)

The Wide Field Camera 3 (WFC3) is a fourth-generation imaging instrument installed on the Hubble Space Telescope (HST) in May 2009. It contains both an IR and a UVIS channel. The latter, which covers the 200-1000nm spectral range, consists of two 2K x 4K CCD chips along with 62 spectral elements and one grism. The two CCD chips were manufactured on different wafers. As a result, there are differences in the two chips’ properties and behaviors, such as their lithography imprint patterns, their sensitivity responses, and their measured quantum efficiency (QE), particularly in the UV. Therefore, the WFC3 team developed a chip-dependent approach to the photometric calibration, where each chip now has its own separate calibration. We discuss the impacts of this new approach and its implementation in the calibration pipeline, presenting the new zero points and header keywords, as well as the new flat fields. We also present the latest trends in the contamination monitoring, which obtains regular imaging and grism spectroscopy of the white dwarf, GRW+70, in key filters F218W, F225W, F336W, F814W, and F606W.No contamination effects have been detected, though there is evidence for a small photometric drift (<1% over 3 years). We anticipate that these efforts will improve UV imaging with WFC3.

Gosmeyer, Catherine; Baggett, Sylvia M.; Bowers, Ariel; Dahlen, Tomas; Deustua, Susana E.; Hammer, Derek; Mack, Jennifer

2014-06-01

360

Using Colors to Improve Photometric Metallicity Estimates for Galaxies  

NASA Astrophysics Data System (ADS)

There is a well known correlation between the mass and metallicity of star-forming galaxies. Because mass is correlated with luminosity, this relation is often exploited, when spectroscopy is not available, to estimate galaxy metallicities based on single band photometry. However, we show that galaxy color is typically more effective than luminosity as a predictor of metallicity. This is a consequence of the correlation between color and the galaxy mass-to-light ratio and the recently discovered correlation between star formation rate (SFR) and residuals from the mass-metallicity relation. Using Sloan Digital Sky Survey spectroscopy of ~180, 000 nearby galaxies, we derive "LZC relations," empirical relations between metallicity (in seven common strong line diagnostics), luminosity, and color (in 10 filter pairs and four methods of photometry). We show that these relations allow photometric metallicity estimates, based on luminosity and a single optical color, that are ~50% more precise than those made based on luminosity alone; galaxy metallicity can be estimated to within ~0.05-0.1 dex of the spectroscopically derived value depending on the diagnostic used. Including color information in photometric metallicity estimates also reduces systematic biases for populations skewed toward high or low SFR environments, as we illustrate using the host galaxy of the supernova SN 2010ay. This new tool will lend more statistical power to studies of galaxy populations, such as supernova and gamma-ray burst host environments, in ongoing and future wide-field imaging surveys.

Sanders, N. E.; Levesque, E. M.; Soderberg, A. M.

2013-10-01

361

San Pedro Mártir Mid-Infrared Photometric System  

NASA Astrophysics Data System (ADS)

With the goal of defining the San Pedro Martir Mid-infrared Photometric System (SPM-MIR), observations of well-defined calibration stars were carried out on 9 photometric runs from 2000 to 2005. The mid-infrared (2 - 28 ?m) camera CID-BIB of the Observatorio Astronómico Nacional was used. A set of 9 filters, the ``silicate'' series SiN, SiO, SiP, SiQ, SiR, SiS, the broad-band N (10.8 ?m) filter, and the narrow-band QH2 (17.15 ?m) and Q2 (18.7 ?m), was used to derive the extinction coefficients and zero magnitude points. Atmospheric extinction corrections were carried out making use of Padé approximants and we found a linear dependence on the parameters with the low air mass extinction coefficient. The atmospheric transmission curves and extinction coefficients of SPM were compared with those obtained for the Mauna Kea site. Color terms were derived using a set of IRAS LSR sources observed with the CID-BIB.

Salas, L.; Cruz-González, I.; Tapia, M.

2006-10-01

362

DETECTION OF KOI-13.01 USING THE PHOTOMETRIC ORBIT  

SciTech Connect

We use the KOI-13 transiting star-planet system as a test case for the recently developed BEER algorithm, aimed at identifying non-transiting low-mass companions by detecting the photometric variability induced by the companion along its orbit. Such photometric variability is generated by three mechanisms: the beaming effect, tidal ellipsoidal distortion, and reflection/heating. We use data from three Kepler quarters, from the first year of the mission, while ignoring measurements within the transit and occultation, and show that the planet's ephemeris is clearly detected. We fit for the amplitude of each of the three effects and use the beaming effect amplitude to estimate the planet's minimum mass, which results in M{sub p} sin i = 9.2 {+-} 1.1 M{sub J} (assuming the host star parameters derived by Szabo et al.). Our results show that non-transiting star-planet systems similar to KOI-13.01 can be detected in Kepler data, including a measurement of the orbital ephemeris and the planet's minimum mass. Moreover, we derive a realistic estimate of the amplitudes uncertainties, and use it to show that data obtained during the entire lifetime of the Kepler mission of 3.5 years will allow detecting non-transiting close-in low-mass companions orbiting bright stars, down to the few Jupiter mass level. Data from the Kepler Extended Mission, if funded by NASA, will further improve the detection capabilities.

Shporer, Avi [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Santa Barbara, CA 93117 (United States); Jenkins, Jon M.; Seader, Shawn E.; Smith, Jeffrey C.; Thompson, Susan E.; Twicken, Joseph D. [SETI Institute/NASA Ames Research Center, Moffett Field, CA 94035 (United States); Rowe, Jason F.; Sanderfer, Dwight T. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Still, Martin D. [Bay Area Environmental Research Institute/NASA Ames Research Center, Moffett Field, CA 94035 (United States); Welsh, William F., E-mail: ashporer@lcogt.net [Astronomy Department, San Diego State University, San Diego, CA 92182 (United States)

2011-12-15

363

a Photometric Study of the Neglected Eclipsing Binary BS Cassiopeiae  

NASA Astrophysics Data System (ADS)

We present multicolor charge-coupled device (CCD) photometry for the eclipsing binary BS Cassiopeiae, observed on four nights between 2007 December and 2008 January. Using the Wilson-Devinney program, the photometric solution was derived from our BVR observations. Photometric results indicated that BS Cas is a W-subtype binary, whose mass ratio and overcontact degree are q = 0.2834(±0.0010) and f = 31.6%(±1.1%), respectively. Light curves of BS Cas present a typical O'Connell effect, which may be attributed to dark spot activity of the primary component. A detailed period analysis reveals that there exists a cyclic variation overlaying a secular period decrease, based on either all available light minimum times or recent light minimum times since 1989. The low-amplitude cyclic variation with a period of about 13 yr can be explained by either the light-time effect or cyclic magnetic activity of both components. The long-term orbital period decrease suggests that BS Cas is undergoing mass transfer from the primary component to the secondary one. With its mass transfer and accompanying angular momentum loss, this binary will evolve into a deeper contact configuration.

Yang, Y.-G.; Wei, J.-Y.; He, J.-J.

2008-08-01

364

Spectrophotometric extractive titrations-IV Determination of zinc in germanium dioxide and germanium chloride.  

PubMed

A simple and selective determination of zinc in germanium chloride and germanium dioxide is described. The sample is dissolved in sodium potassium tartrate solution and zinc is titrated spectrophotometrically at 532 mug( with a dithizone solution in carbon tetrachloride without discarding the organic phase. Interfering ions such as Bi(III), Cu(II), Cd(II), Co(II), Ni(II), Pb(II), Sn(II), Fe(II), Fe(III), Mn(II) and T1(I) are masked with bis(2-hydroxyethyl)dithiocarbamate. The detection limit is 3-23 x 10(-5)% of zinc and this may be lowered by taking a larger sample and by performing the analysis in a closed system. A simplified technique, consisting of the simultaneous titration of the sample and blank, is described. PMID:18960156

Galík, A

1967-07-01

365

Standard test method for aluminum in iron ores by complexometric titration  

SciTech Connect

This method covers the determination of aluminum in iron ores, concentrates, and agglomerates in the concentration range from 0.25 to 5% aluminium. The sample is fused in a zirconium crucible with a mixed flux of sodium carbonate and sodium peroxide. The fused mass is dissolved in dilute hydrochloric acid. The R/sub 2/O/sub 3/ hydroxides are precipitated with ammonia and redissolved in hydrochloric acid. Iron, titanium, etc., are removed with cupferron and chloroform. The aqueous phase is treated with nitric and perchloric acids and evaporated to dryness. After dissolving in dilute hydrochloric acid, the solution is filtered, and the filtrate is treated with an excess of ethylenediaminetetraacetic acid (EDTA). The excess EDTA is titrated with a standard zinc solution using xylenol orange indicator. Ammonium fluoride is added to release the EDTA bound to aluminum. This EDTA is then titrated with standard zinc solution, and the percent aluminum is calculated.

Not Available

1980-01-01

366

Complexometric titration of total iron with o-mercaptobenzoic acid as indicator.  

PubMed

The soluble deep blue complex of iron(II) with o-mercaptobenzoic acid in aqueous pyridine medium (pH 6.4-7.4) can be titrated with EDTA at room temperature with a sharp colour change from blue to light yellow. o-Mercaptobenzoic acid forms a 2:1 complex with iron(II), maximum absorption at 600 nm. Its stability constant was found to be log K = 7.7. With iron(III), a transient blue colour is first formed which soon becomes colourless and then on the addition of excess of reagent, the deep blue complex is formed on reduction of the iron(III). Iron can be titrated in the presence of copper, if the latter is masked with sodium thiosulphate. Cobalt and nickel interfere. Common anions such as chloride, tartrate, phosphate, oxalate, citrate and acetate have no interference. PMID:18960715

Bhandari, L M; Khosla, M M; Rao, S P

1970-02-01

367

Closed loop odorant injection control utilizing a feedforward and titrator control system  

SciTech Connect

Precise measurement of downstream odorant concentration and quick response during flow changes characterize this new concept in odorant control. Incorporating a closed-loop automatic odorant-injection system, this design employs an indicating process controller and an odorant analyzer (Titrator) to provide feedback control. A feedforward control system handles short-term responses to flow changes. Assembled from high-quality, off-the-shelf components, the unit is easy to calibrate and maintain.

Bosse, P.H.; Smith, G.A.

1982-08-01

368

Surface defect site density on single walled carbon nanotubes by titration  

Microsoft Academic Search

Closed end single walled carbon nanotubes (c-SWNT) purified by acidic oxidation have been studied in order to determine the fraction of oxidized carbon sites present. This has been done by measuring the evolution of CO2(g) and CO(g) on heating to 1273 K. Following a 1273 K treatment, the defect sites were titrated repeatedly with O3. The results indicate that ?5%

Douglas B. Mawhinney; Viktor Naumenko; Anya Kuznetsova; John T. Yates Jr; J. Liu; R. E. Smalley

2000-01-01

369

Characterization of electrostatic binding sites of extracellular polymers by linear programming analysis of titration data  

Microsoft Academic Search

Electrostatic binding sites of extracellular poly- meric substances (EPS) were characterized from titration data using linear programming analysis. Test results for three synthetic solutions of given solutes comprising amino, carboxyl, and phenolic groups indicated that this method was able to identify the electrostatic binding sites. For the six sites with pKa between 3 and 10, the estimated pKa deviated 0.11

Hong Liu; Herbert H. P. Fang

2002-01-01

370

Enzyme activity determination on macromolecular substrates by isothermal titration calorimetry: application to mesophilic and psychrophilic chitinases  

Microsoft Academic Search

Isothermal titration calorimetry has been applied to the determination of the kinetic parameters of chitinases (EC 3.2.1.14) by monitoring the heat released during the hydrolysis of chitin glycosidic bonds. Experiments were carried out using two different macromolecular substrates: a soluble polymer of N-acetylglucosamine and the insoluble chitin from crab shells. Different experimental temperatures were used in order to compare the

Thierry Lonhienne; Etienne Baise; Georges Feller; Vassilis Bouriotis; Charles Gerday

2001-01-01

371

Determination of Hydrogen Fluoride and Uranium (VI) in Crude Uranium Hexafluoride by Hydrolysis and Potentiometric Titration  

Microsoft Academic Search

A simple method for determining HF and U(VI) in a hydrolyzed solution of UF6 by alkalimetry is described.About 1 g of UF6 was taken in a polytrifluoromonochloroethylene tube, and hydrolyzed with about 50 ml of water in a closed polyethylene bottle. Using a glass electrode, HF in the hydrolyzed solution was titrated potentiometrically with an alkali solution, after the U(VI)

Haruka SHINOHARA; Kimie IZAWA; Shigeo TSUJIMURA; Kenji MOTOJIMA

1967-01-01

372

pH-Metric determination of acid numbers in petroleum oils without titration  

Microsoft Academic Search

A new pH-metric method without titration has been developed for determination of acid numbers lower than 0.1 mg (KOH) g?1 (oil) in petroleum oils such as White, Transformer and Basic oils. The method is based on rapid and complete extraction of acids from an oil test portion into the novel reagent and measurement of the conditional pH in the `oil–reagent'

Ya. I. Tur'yan; E. Strochkova; O. Yu. Berezin; I. Kuselman; A. Shenhar

1998-01-01

373

Probing the Energetics of Antigen–Antibody Recognition by Titration Microcalorimetry  

Microsoft Academic Search

Our understanding of the energetics that govern antigen–antibody recognition lags behind the increasingly rapid accumulation of structural information on antigen–antibody complexes. Thanks to the development of highly sensitive microcalorimeters, the thermodynamic parameters of antigen–antibody interactions can now be measured with precision and using only nanomole quantities of protein. The method of choice is isothermal titration calorimetry, in which a solution

Ilian Jelesarov; Lukas Leder; Hans Rudolf Bosshard

1996-01-01

374

Calorimetry, activity, and micro-FTIR analysis of CO chemisorption, titration, and oxidation on supported Pt  

NASA Technical Reports Server (NTRS)

The value of in situ analysis on CO chemisorption, titration and oxidation over supported Pt catalysts using calorimetry, catalytic and micro-FTIR methods is illustrated using silica- and titania-supported samples. Isothermal CO-O and O2-CO titrations have not been widely used on metal surfaces and may be complicated if some oxide supports are reduced by CO titrant. However, they can illuminate the kinetics of CO oxidation on metal/oxide catalysts since during such titrations all O and CO coverages are scanned as a function of time. There are clear advantages in following the rates of the catalyzed CO oxidation via calorimetry and gc-ms simultaneously. At lower temperatures the evidence they provide is complementary. CO oxidation and its catalysis of CO oxidation have been extensively studied with hysteresis and oscillations apparent, and the present results suggest the benefits of a combined approach. Silica support porosity may be important in defining activity-temperature hysteresis. FTIR microspectroscopy reveals the chemical heterogeneity of the catalytic surfaces used; it is interesting that the evidence with regard to the dominant CO surface species and their reactivities with regard to surface oxygen for present oxide-supported Pt are different from those seen on graphite-supported Pt.

Sermon, Paul A.; Self, Valerie A.; Vong, Mariana S. W.; Wurie, Alpha T.

1990-01-01

375

Escherichia coli strains that allow antibiotic-free plasmid selection and maintenance by repressor titration  

PubMed Central

We report the construction of two novel Escherichia coli strains (DH1lacdapD and DH1lacP2dapD) that facilitate the antibiotic-free selection and stable maintenance of recombinant plasmids in complex media. They contain the essential chromosomal gene, dapD, under the control of the lac operator/promoter. Unless supplemented with IPTG (which induces expression of dapD) or DAP, these cells lyse. However, when the strains are transformed with a multicopy plasmid containing the lac operator, the operator competitively titrates the LacI repressor and allows expression of dapD from the lac promoter. Thus transformants can be isolated and propagated simply by their ability to grow on any medium by repressor titration selection. No antibiotic resistance genes or other protein expressing sequences are required on the plasmid, and antibiotics are not necessary for plasmid selection, making these strains a valuable tool for therapeutic DNA and recombinant protein production. We describe the construction of these strains and demonstrate plasmid selection and maintenance by repressor titration, using the new pORT plasmid vectors designed to facilitate recombinant DNA exploitation.

Cranenburgh, Rocky M.; Hanak, Julian A. J.; Williams, Steven G.; Sherratt, David J.

2001-01-01

376

Protein-salt binding data from potentiometric titrations of lysozyme in aqueous solutions containing KCl  

SciTech Connect

An existing method for potentiometric titrations of proteins was improved, tested and applied to titrations of the enzyme hen-egg-white lysozyme in aqueous solutions containing KCl at ionic strengths from 0.1 M to 2.0 M at 25 C. Information about the protein`s net charge dependence on pH and ionic strength were obtained and salt binding numbers for the system were calculated using a linkage concept. For the pH range 2.5--11.5, the net charge slightly but distinctly increases with increasing ionic strength between 0.1 M and 2.0 M. The differences are most distinct in the pH region below 5. Above pH 11.35, the net charge decreases with increasing ionic strength. Preliminary calculation of binding numbers from titration curves at 0.1 M and 1.0 M showed selective association of chloride anions and expulsion of potassium ions at low pH. Ion-binding numbers from this work will be used to evaluate thermodynamic properties and to correlate crystallization or precipitation phase-equilibrium data in terms of a model based on the integral-equation theory of fluids which is currently under development.

Engmann, J.; Blanch, H.W.; Prausnitz, J.M. [Univ. of California, Berkeley, CA (United States). Dept. of Chemical Engineering]|[Lawrence Berkeley National Lab., CA (United States). Chemical Sciences Div.

1997-03-01

377

Analysis of dose-response in flexible dose titration clinical studies.  

PubMed

Assessing dose-response from flexible-dose clinical trials (e.g., titration or dose escalation studies) is challenging and often problematic due to the selection bias caused by 'titration-to-response'. We investigate the performance of a dynamic linear mixed-effects (DLME) model and marginal structural model (MSM) in evaluating dose-response from flexible-dose titration clinical trials via simulations. The simulation results demonstrated that DLME models with previous exposure as a time-varying covariate may provide an unbiased and efficient estimator to recover exposure-response relationship from flexible-dose clinical trials. Although the MSM models with independent and exchangeable working correlations appeared to be able to recover the right direction of the dose-response relationship, it tended to over-correct selection bias and overestimated the underlying true dose-response. The MSM estimators were also associated with large variability in the parameter estimates. Therefore, DLME may be an appropriate modeling option in identifying dose-response when data from fixed-dose studies are absent or a fixed-dose design is unethical to be implemented. PMID:22407972

Xu, Xu Steven; Yuan, Min; Nandy, Partha

2012-01-01

378

Prediction of aluminum, uranium, and co-contaminants precipitation and adsorption during titration of acidic sediments.  

PubMed

Batch and column recirculation titration tests were performed with contaminated acidic sediments. A generic geochemical model was developed combining precipitation, cation exchange, and surface complexation reactions to describe the observed pH and metal ion concentrations in experiments with or without the presence of CO2. Experimental results showed a slow pH increase due to strong buffering by Al hydrolysis and precipitation and CO2 uptake. The cation concentrations generally decreased at higher pH than those observed in previous tests without CO2. Using amorphous Al(OH)3 and basaluminite precipitation reactions and a cation exchange selectivity coefficient K(Na\\Al) of 0.3, the model approximately described the observed (1) pH titration curve, (2) Ca, Mg, and Mn concentration by cation exchange, and (3) U concentrations by surface complexation with Fe hydroxides at pH < 5 and with liebigite (Ca2UO2(CO3)3·10H2O) precipitation at pH > 5. The model indicated that the formation of aqueous carbonate complexes and competition with carbonate for surface sites could inhibit U and Ni adsorption and precipitation. Our results suggested that the uncertainty in basaluminite solubility is an important source of prediction uncertainty and ignoring labile solid phase Al underestimates the base requirement in titration of acidic sediments. PMID:23641798

Tang, Guoping; Luo, Wensui; Watson, David B; Brooks, Scott C; Gu, Baohua

2013-06-01

379

Investigations of Sso7d catalytic residues by NMR titration shifts and electrostatic calculations.  

PubMed

Sso7d is a small basic protein consisting of 62 amino acids isolated from the thermoacidophilic archeobacterium Sulfolobus solfataricus. The protein is endowed with DNA binding properties, RNase activity, and the capability of rescuing aggregated proteins in the presence of ATP. In this study, the electrostatic properties of Sso7d are investigated by using the Poisson-Boltzmann calculation of the surface potential distribution and following by NMR spectroscopy the proton chemical shift pH titration of acidic residues. Although the details of the catalytic mechanism still have to be defined, the results from NMR experiments confirm the possible involvement of Glu35 as the proton acceptor in the catalytic reaction, as seen by its abnormally high pK(a) value. Poisson-Boltzmann calculations and NMR titration shifts suggest the presence of a possible hydrogen bond between Glu35 and Tyr33, with a consequent rather rigid arrangement at these positions. Comparison with RNase T1 suggests that Tyr7 may be a good candidate for acting as a proton donor in the active site of Sso7d as shown by its low phenolic pK(a) of approximately 9.3. Titration experiments performed with the UpA, a RNA dinucleotide model, showed that the protein residues affected by the interaction are mainly located in a different region with respect to the surface affected by DNA recognition, in good agreement with the surface potential distribution found with electrostatic calculations. PMID:12578354

Consonni, Roberto; Arosio, Ivana; Belloni, Barbara; Fogolari, Federico; Fusi, Paola; Shehi, Erlet; Zetta, Lucia

2003-02-18

380

Statistical mechanical model of coupled transcription from multiple promoters due to transcription factor titration  

NASA Astrophysics Data System (ADS)

Transcription factors (TFs) with regulatory action at multiple promoter targets is the rule rather than the exception, with examples ranging from the cAMP receptor protein (CRP) in E. coli that regulates hundreds of different genes simultaneously to situations involving multiple copies of the same gene, such as plasmids, retrotransposons, or highly replicated viral DNA. When the number of TFs heavily exceeds the number of binding sites, TF binding to each promoter can be regarded as independent. However, when the number of TF molecules is comparable to the number of binding sites, TF titration will result in correlation (“promoter entanglement”) between transcription of different genes. We develop a statistical mechanical model which takes the TF titration effect into account and use it to predict both the level of gene expression for a general set of promoters and the resulting correlation in transcription rates of different genes. Our results show that the TF titration effect could be important for understanding gene expression in many regulatory settings.

Rydenfelt, Mattias; Cox, Robert Sidney, III; Garcia, Hernan; Phillips, Rob

2014-01-01

381

Direct spectrophotometric detection of the endpoint in metachromatic titration of polydiallyldimethylammonium chloride in water  

NASA Astrophysics Data System (ADS)

Polydiallyldimethylammonium chloride (poly-DADMAC) is a water soluble polymer that easily ionizes when dissolved in water. This cationic polyelectrolyte is mainly used as a flocculant within the water treatment industry, but little is known of its toxicological properties or its fate in the environment. It is often assumed that the polyelectrolyte sorbs onto solid surfaces in the water treatment stream and may be removed with the sludge or by a sand bed filter; which may not always be the case. In any event, reliable analytical techniques are needed for the determination of poly-DADMAC in matrices of environmental relevance. Metachromatic polyelectrolyte titration was used to quantify poly-DADMAC in model and tap water samples. We compared a routine visual titration method with a direct spectrophotometric technique that uses a dip probe, spectrometer, and computer. The direct spectrophotometric technique allowed for the determination of titration curves at 634 nm and 510 nm, whereby the later value has never been successfully utilised in the literature. The method simplifies the data analysis, and our recovery and matrix interference experiments demonstrate that the method is accurate, precise, and robust. The detection limit for this method was 0.1 mg L-1 in model water and 0.5 mg L-1 in tap water. The limit of quantification for both water matrices was 0.5 mg L-1.

Gumbi, B.; Ngila, J. C.; Ndungu, P. G.

382

Use of sodium dodecyl sulphate to clarify the end-point of anodic-stripping complexometric titrations.  

PubMed

It has been found that addition of sodium dodecyl sulphate will completely suppress the dissociation of the copper-EDTA complex at the electrode surface in the anodic-stripping complexometric titration of copper and make the end-point of the titration very clear. The addition of SDS also makes it possible to titrate traces of nitrilotriacetic acid, which forms a copper complex that is less stable than the EDTA complex. The effect of SDS is presumed to be due to electrostatic repulsion between the negative charges of adsorbed SDS and the metal complex at the electrode surface. PMID:18963484

Tanaka, S I; Morimoto, Y; Taga, M; Yoshida, H

1983-11-01

383

Consecutive complexometric titration of thorium and rare earths in ores. (Kuang shi zhong du he xi tu de lian xu luo he di ding).  

National Technical Information Service (NTIS)

The major problem present in the EDTA consecutive complexometric titration of thorium and rare earths lies in the fact that during the adjustment of pH 5--6 for the titration of rare earths and after the titration of thorium, because of the formation of t...

D. Chen Y. Zhon G. Hu

1990-01-01

384

Clinical Guidelines for the Manual Titration of Positive Airway Pressure in Patients with Obstructive Sleep Apnea  

PubMed Central

Summary: Positive airway pressure (PAP) devices are used to treat patients with sleep related breathing disorders (SRBDs), including obstructive sleep apnea (OSA). After a patient is diagnosed with OSA, the current standard of practice involves performing attended polysomnography (PSG), during which positive airway pressure is adjusted throughout the recording period to determine the optimal pressure for maintaining upper airway patency. Continuous positive airway pressure (CPAP) and bilevel positive airway pressure (BPAP) represent the two forms of PAP that are manually titrated during PSG to determine the single fixed pressure of CPAP or the fixed inspiratory and expiratory positive airway pressures (IPAP and EPAP, respectively) of BPAP for subsequent nightly usage. A PAP Titration Task Force of the American Academy of Sleep Medicine reviewed the available literature. Based on this review, the Task Force developed these recommendations for conducting CPAP and BPAP titrations. Major recommendations are as follows: (1) All potential PAP titration candidates should receive adequate PAP education, hands-on demonstration, careful mask fitting, and acclimatization prior to titration. (2) CPAP (IPAP and/or EPAP for patients on BPAP) should be increased until the following obstructive respiratory events are eliminated (no specific order) or the recommended maximum CPAP (IPAP for patients on BPAP) is reached: apneas, hypopneas, respiratory effort-related arousals (RERAs), and snoring. (3) The recommended minimum starting CPAP should be 4 cm H2O for pediatric and adult patients, and the recommended minimum starting IPAP and EPAP should be 8 cm H2O and 4 cm H2O, respectively, for pediatric and adult patients on BPAP. (4) The recommended maximum CPAP should be 15 cm H2O (or recommended maximum IPAP of 20 cm H2O if on BPAP) for patients <12 years, and 20 cm H2O (or recommended maximum IPAP of 30 cm H2O if on BPAP) for patients ?12 years. (5) The recommended minimum IPAP-EPAP differential is 4 cm H2O and the recommended maximum IPAP-EPAP differential is 10 cm H2O (6) CPAP (IPAP and/or EPAP for patients on BPAP depending on the type of event) should be increased by at least 1 cm H2O with an interval no shorter than 5 min, with the goal of eliminating obstructive respiratory events. (7) CPAP (IPAP and EPAP for patients on BPAP) should be increased from any CPAP (or IPAP) level if at least 1 obstructive apnea is observed for patients <12 years, or if at least 2 obstructive apneas are observed for patients ?12 years. (8) CPAP (IPAP for patients on BPAP) should be increased from any CPAP (or IPAP) level if at least 1 hypopnea is observed for patients <12 years, or if at least 3 hypopneas are observed for patients ?12 years. (9) CPAP (IPAP for patients on BPAP) should be increased from any CPAP (or IPAP) level if at least 3 RERAs are observed for patients <12 years, or if at least 5 RERAs are observed for patients ?12 years. (10) CPAP (IPAP for patients on BPAP) may be increased from any CPAP (or IPAP) level if at least 1 min of loud or unambiguous snoring is observed for patients <12 years, or if at least 3 min of loud or unambiguous snoring are observed for patients ?12 years. (11) The titration algorithm for split-night CPAP or BPAP titration studies should be identical to that of full-night CPAP or BPAP titration studies, respectively. (12) If the patient is uncomfortable or intolerant of high pressures on CPAP, the patient may be tried on BPAP. If there are continued obstructive respiratory events at 15 cm H2O of CPAP during the titration study, the patient may be switched to BPAP. (13) The pressure of CPAP or BPAP selected for patient use following the titration study should reflect control of the patient's obstructive respiration by a low (preferably <5 per hour) respiratory disturbance index (RDI) at the selected pressure, a minimum sea level SpO2 above 90% at the pressure, and with a leak within acceptable parameters at the pressure. (14) An optimal titration reduces RDI <5

2008-01-01

385

Dust effects on photometric parameters in spirals (Pastrav+, 2013)  

NASA Astrophysics Data System (ADS)

The tables from appendix A (tableA) list the corrections for projection effects while the tables from appendix B (tableB) list the corrections for dust. The corrections are given for the derived photometric parameters of the main morphological components of spiral galaxies: disks, thin disks and bulges. The corrections are given as a function of inclination, central face-on optical depth in the B band taufB, and wavelength. The parameter space covered by this is as follows: taufB={0.1,0.3,0.5,1.0,2.0,4.0,8.0} wavelength (in Angstrom): 912,1350,1500,1650,2000,2200,2500,2800,3650,4430,5640,8090,12590,22000 We note here that in the model of Popescu et al. (2011, Cat. J/A+A/527/A109) the disk consists of an old stellar population that mainly emits in the optical/near-infrared range. Because of this the disk is not taken to emit in the ultraviolet, and therefore the corrections for disks are only listed in the optical/near-infrared range. Similarly, the corrections for bulge are also presented only for the optical/near-infrared range. The corrections are provided for photometric fits done with the following functions: i) exponential functions for disks and thin disks ii) variable index Sersic functions for disks, thin disks and bulges iii) de Vaucouleurs functions for bulges. For the case of bulges corrections are provided for both exponential bulges (i.e. Sersic index fixed to unity) and de Vaucouleurs bulges. The photometric parameters for which corrections are listed are as follows: R - the exponential scalelength Reff - the effective radius delta SB - the central surface brightness of the disk Q - the axis ratio of the disk nsers - the Sersic index To facilitate access to the information and to allow the corrections to be calculated for any inclination, the corrections are presented in the form of polynomial function fits. For most of the cases the fitted function is given by Eq. 14 of the paper. In the case of the axis-ratio of disks, Q, the fits are done with a combination of a polynomial and a constant, as given by Eqs. 19 and 21 of the paper. (65 data files).

Pastrav, B. A.; Popescu, C. C.; Tuffs, R. J.; Sansom, A. E.

2013-04-01

386

A critical assessment of the Hapke photometric model  

NASA Astrophysics Data System (ADS)

The photometric model developed by Hapke is commonly used to study surface structure and composition of atmosphereless celestial bodies using photometric measurements. However, this model has shortcomings that weaken its applications. For instance, some of the model parameters are empirical and mutually dependent. Moreover, the photometric model is eclectic and approximate; e.g., (1) the model simultaneously considers the single-scattering phase-function as backscattering and isotropic when describing, respectively, incoherent and coherent multiple scattering, which is physically impossible; (2) the approximation of the incoherent multiple scattering function takes into account the function anisotropy for the incident and emergent angles, but ignores the anisotropy for the azimuth angle that is of equal importance; (3) the model also ignores the dependence of the shadow-hiding effect of particles and coherent-backscattering enhancement on illuminating/viewing geometry, accounting only for the phase-angle component; (4) the azimuthal dependence of the shadow-hiding effect on random topographies is introduced ad hoc and is not verified; moreover, the shadow phase function may produce a non-physical maximum at large angles of viewing. We test the Hapke model using a computer simulation of ray-tracing in particulate surfaces, showing significant differences between the Hapke model and the ray-tracing results. We also apply the Hapke model to the interpretation of laboratory photometry of several well-characterized powdered samples measured in two wavelengths. The samples were measured in three states: as particles in air, as a particulate surface formed by freely spilled particles, and after compressing the particulate surface. The Hapke model parameters were completely inconsistent in the interpretation of these laboratory data. Our attempt to map the Hapke parameters using a series of telescopic calibrated images of the Moon acquired at different phase angles demonstrates that the model does not provide a physically meaningful distribution of its parameters. We also suggest that the small increase of the circular polarization ratio ?C at decreasing phase angle (<10°), which is observed for lunar samples, is not evidence of the coherent-backscattering effect of the Moon. We suggest that Clementine observations carried out with the UV-Vis and NIR cameras demonstrate that the coherent-backscattering effect exists only for bright lunar surface areas with albedo higher than 30%.

Shkuratov, Y.; Kaydash, V.; Korokhin, V.; Velikodsky, Y.; Petrov, D.; Zubko, E.; Stankevich, D.; Videen, G.

2012-12-01

387

Exploring the Variable Sky with LINEAR. I. Photometric Recalibration with the Sloan Digital Sky Survey  

Microsoft Academic Search

We describe photometric recalibration of data obtained by the asteroid survey LINEAR. Although LINEAR was designed for astrometric discovery of moving objects, the data set described here contains over 5 billion photometric measurements for about 25 million objects, mostly stars. We use Sloan Digital Sky Survey (SDSS) data from the overlapping ~10,000 deg2 of sky to recalibrate LINEAR photometry and

Branimir Sesar; J. Scott Stuart; Zeljko Ivezic; Dylan P. Morgan; Andrew C. Becker; Przemyslaw Wozniak

2011-01-01

388

On the Compared Accuracy and Reliability of Spectroscopic and Photometric Redshift Measurements  

Microsoft Academic Search

We present a comparison between the catalog of spectroscopic redshifts in the Hubble Deep Field (HDF) recently published by Cohen and collaborators and the redshifts that our group has measured for the same objects using photometric techniques. This comparison is performed in order to fully characterize the errors associated with the photometric redshift technique. The compilation of spectroscopic redshifts incorporates

Alberto Fernández-Soto; Kenneth M. Lanzetta; Hsiao-Wen Chen; Sebastian M. Pascarelle; Noriaki Yahata

2001-01-01

389

Statistical Properties of Bright Galaxies in the Sloan Digital Sky Survey Photometric System  

Microsoft Academic Search

We investigate the photometric properties of 456 bright galaxies using imaging data recorded during the commissioning phase of the Sloan Digital Sky Survey (SDSS). Morphological classification is carried out by correlating results of several human classifiers. Our purpose is to examine the statistical properties of color indices, scale lengths, and concentration indices as functions of morphology for the SDSS photometric

Kazuhiro Shimasaku; Masataka Fukugita; Mamoru Doi; Masaru Hamabe; Takashi Ichikawa; Sadanori Okamura; Maki Sekiguchi; Naoki Yasuda; István Csabai; Shin-Ichi Ichikawa; Zeljko Ivezic; Peter Z. Kunszt; Donald P. Schneider; Gyula P. Szokoly; Masaru Watanabe; Donald G. York

2001-01-01

390

Indirect Photometric and Fluorometric Detection in High-Performance Liquid Chromatography: A Tutorial Review  

Microsoft Academic Search

A review of indirect photometric and fluorometric detection in high-performance liquid chromatography (HPLC) is presented. A functional definition of indirect detection, somewhat broader and simpler than what was often used to characterize these techniques, was employed for this review. Emphasis was placed on distinguishing different approaches to indirect photometric and fluorometric detection in HPLC based on the interactions which occur

Xiaoxuan Shen; Sterling A. Tomellini

2007-01-01

391

Contraceptive procedures.  

PubMed

Although most women desire to control the size and spacing of their family, the rate of unintended pregnancy in the United States remains high, with approximately half of all pregnancies being unintended. Reducing unintended pregnancy is a national public health goal, and the increased use of long-acting reversible contraceptives (LARCs) (intrauterine devices and implants) can help meet this goal. LARCs are among the most effective forms of contraception available. There are few contraindications to their use, and insertion and removal are straightforward procedures that are well tolerated in the outpatient office setting. PMID:24286997

Beasley, Anitra; Schutt-Ainé, Ann

2013-12-01

392

Determination of NO/sub 2//sup -//NO/sub 3//sup -/ mixtures by titration with ascorbic acid  

SciTech Connect

The analysis of nitrite-nitrate mixtures by indirect titration with ascorbic acid performed before and after passage through a reducing Cd column is proposed and discussed with particular reference to experimental conditions, calculation scheme and concentration ranges.

Campanella, L.; Paoletti, A.M.

1982-01-01

393

Miminum Distance and Perturbation Methods in Photometric Classification of Stars for GAIA  

NASA Astrophysics Data System (ADS)

A number of classification methods proposed for the l Gaia mission are aimed at determining the main astrophysical parameters (effective temperature, gravity, metallicity and interstellar reddening) of stars from future photometric data for investigation of the structure and evolution of our Galaxy. In the absence of real observations and the final photometric system, extensive simulated data with different photometric systems are being analyzed at present. In this paper the minimum distance and perturbation methods have been applied for stellar classification using simulated data in the 1X photometric system for l Gaia-1 and l Gaia-2 configurations. The conclusion is that both methods are able to provide reliable classification results but the accuracies achieved with the minimum distance method are somewhat better, and this method seems to be preferable. Our version of the minimum distance method will be applied to the simulated data based on a modified l Gaia instrument design and for other recently proposed photometric systems.

Malyuto, V.; Shvelidze, T.

394

Photometric and polarimetric study of two BL LAC objects  

SciTech Connect

The results are given of polarimetric and photometric observations of the BL Lac objects OI 090.4 over the period 1979-1982 and B2 1418 + 54 over the period 1980-1982. For both objects it was noted that there was variability on a time scale of from several years to several days. The comparison of the polarimetric parameters indicates the existence of a preferred direction of polarization both for B2 1418 + 54 (theta /sub O/ = 120/sup 0/), and for OI 090.4 (theta /sub O/ = 50/sup 0/), which points to a stable magnetic field. For OI 090.4 it was observed that there was a certain dependence of the polarization parameters on the wavelength.

Marchenko, S.G.

1985-07-01

395

Keplerian Periodicity in the Photometric Variability of VV Serpentis  

NASA Astrophysics Data System (ADS)

We present the results of our long-term photometric monitoring effort of VV Serpentis, a Herbig Ae star with an edge-on disk that is known to undergo periodic extinction events. We combine our 177 nights of data from the ANDICAM simultaneous visible/IR imager with two data sets from the literature to create a large, statistically significant, 1834 night data set spanning 23 observing seasons. A Lomb-Scargle analysis of this data set shows a broad peak in the periodigram at 30-35 days. This period corresponds to the Keplerian orbital period of the inner rim of the disk, suggesting that the periodic extinction events are caused by protoplanetary structure, which is expected to form in the same inner regions of the disk.

Kopon, Derek; Close, Laird; Skemer, Andrew

2013-07-01

396

Comprehensive photometric study of the eclipsing binary AW UMa  

NASA Astrophysics Data System (ADS)

Due to its extreme mass ratio, the system AW UMa is considered as one of the most interesting contact binaries. In the present paper, a total of 1289 observations in VRI band were carried out from on 2006 March 7, 8, and 9 at Piszkesteto, Mountain Station of the Konkoly observatory (Hungary). VRI light curves were constructed and a photometric solution of these light curves was obtained by means of Willson-Devinney code. The results show that the primary component is more massive and hotter than the primary component by ˜140 K. A secular period decrease with a rate dP/dE=2.436×10-10 day/cycle was detected. Based on the physical parameters of the system, we investigate the evolutionary state of the components. The primary component is above the zero age main sequence (ZAMS) track, while the secondary component has a larger radius and luminosity than expected from its ZAMS mass.

Elkhateeb, M. M.; Nouh, M. I.

2014-04-01

397

Photometric Study of Radio Galaxies in RATAN-600 "Cold" survey  

NASA Astrophysics Data System (ADS)

We use the RATAN-600 radio telescope for picking up distant radio galaxies. About 100 ultra steep spectrum FRII radio galaxies from the RATAN-600 RC-catalog (Parijskij et al., 1991) were mapped by the VLA and identified with optical objects down to 24-25 R mag. by 6m Russian telescope. An updated list of calibrators with the known redshifts of the same class RGs was compiled to estimate photometric redshifts. The mean redshift of the RC USS FRII RG list happened to be > 1. BVRI photometry was made, and by standard model fittings we estimated color redshifts and the ages of stellar systems of the parent gE galaxies. Several objects were found in which active star formation began in the first billion years after the Big Bang.

Verkhodanov, O. V.; Parijskij, Yurij N.; Soboleva, Natalia S.; Kopylov, Alexander I.; Temirova, Adelina V.; Zhelenkova, Olga P.; Goss, W. M.

398

First CCD UBVI photometric analysis of six open cluster candidates  

NASA Astrophysics Data System (ADS)

We have obtained CCD UBVIKC photometry down to V ˜ 22 for the open cluster candidates Haffner 3, Haffner 5, NGC 2368, Haffner 25, Hogg 3 and Hogg 4 and their surrounding fields. None of these objects have been photometrically studied so far. Our analysis shows that these stellar groups are not genuine open clusters since no clear main sequences or other meaningful features can be seen in their colour-magnitude and colour-colour diagrams. We checked for possible differential reddening across the studied fields that could be hiding the characteristics of real open clusters. However, the dust in the directions to these objects appears to be uniformly distributed. Moreover, star counts carried out within and outside the open cluster candidate fields do not support the hypothesis that these objects are real open clusters or even open cluster remnants.

Piatti, A. E.; Clariá, J. J.; Ahumada, A. V.

2011-04-01

399

A photometric study of the eclipsing binary RX Hercules  

NASA Technical Reports Server (NTRS)

A new photoelectric light curve of RX Hercules, a binary system with similar components, has been analyzed using Wood's computer model. RX Her, using Popper's spectroscopic mass ratio of q = 0.8472, turned out to be composed of a dimmer AO component and a larger B9.5 component. This detached system, upon analysis of the residuals in secondary minimum, shows some asymmetry during ingress which then disappears just before secondary minimum. The eccentricity e = 0.022 determined in this study is a little larger than previously published values of e = 0.018. In combination with the spectroscopic analysis of Popper, and ubvy data of Olson and Hill and Hilditch new photometric elements for RX Her were found.

Jeffreys, K. W.

1980-01-01

400

Photometric monitoring of 47 late-type stars (Strassmeier+, 1999)  

NASA Astrophysics Data System (ADS)

We present continuous multicolor photometry for 47 stars from October 1996 through June 1997. Altogether, 7073 V(RI)c, UBV, and by data points, each the average of three individual readings, were acquired with three automatic photoelectric telescopes (APTs) at Fairborn Observatory in southern Arizona. Most of our targets are chromospherically active single and binary stars of spectral type G to K but there are also four pre-main-sequence objects and three pulsating stars in our sample. The light variability is generally due to rotational modulation of an asymmetrically spotted stellar surface and therefore precise rotational periods and their seasonal variations are determined from Fourier analysis. We also report on photometric variations of ? CrB (A0V) with a period of 0.44534 days. All data are available in numerical form. (6 data files).

Strassmeier, K. G.; Serkowitsch, E.; Granzer, T.

1999-11-01

401

A Probabilistic Approach to Classifying Supernovae UsingPhotometric Information  

SciTech Connect

This paper presents a novel method for determining the probability that a supernova candidate belongs to a known supernova type (such as Ia, Ibc, IIL, etc.), using its photometric information alone. It is validated with Monte Carlo, and both space- and ground-based data. We examine the application of the method to well-sampled as well as poorly sampled supernova light curves and investigate to what extent the best currently available supernova models can be used for typing supernova candidates. Central to the method is the assumption that a supernova candidate belongs to a group of objects that can be modeled; we therefore discuss possible ways of removing anomalous or less well understood events from the sample. This method is particularly advantageous for analyses where the purity of the supernova sample is of the essence, or for those where it is important to know the number of the supernova candidates of a certain type (e.g., in supernova rate studies).

Kuznetsova, Natalia V.; Connolly, Brian M.

2006-12-14

402

CLASH. Photometric + photo-z catalog (Jouvel+, 2014)  

NASA Astrophysics Data System (ADS)

Photometric + photo-z (BPZ) catalog (produced 2011-10-25) for macs1206 (processed 2011-08-15). Note: photo-z estimates are intended for galaxies only. Stars may be identified as having higher values of SExtracor stellarity. Based on 0.065"/pix images produced by AMK's MosaicDrizzle. Objects detected in a weighted sum of ACS+IR images. Pruned by selecting flag5sig=0 (gets rid of cosmic rays and <5-sigma detections). Position, aperture, and shape measurements determined in the detection image Photometry measured in isophotal apertures For each filter, we provide: - magnitude & uncertainty - flux & uncertainty - detection significance Both fluxes and magnitudes have been corrected for: - galactic extinction: E(B-V)=0.06283 mag, magerr = 99, 1-sigma limit: non-detection (flux<0) mag, magerr = -99, 0: unobserved (outside FOV, in chip gap, etc.) This catalog was created by the CLASH Image Pipeline (1 data file).

Jouvel, S.; Host, O.; Lahav, O.; Seitz, S.; Molino, A.; Coe, D.; Postman, M.; Moustakas, L.; Benitez, N.; Rosati, P.; Balestra, I.; Grillo, C.; Bradley, L.; Fritz, A.; Kelson, D.; Koekemoer, A. M.; Lemze, D.; Medezinski, E.; Mercurio, A.; Moustakas, J.; Nonino, M.; Scodeggio, M.; Zheng, W.; Zitrin, A.; Bartelmann, M.; Bouwens, R.; Broadhurst, T.; Donahue, M.; Ford, H.; Graves, G.; Infante, L.; Jimenez-Teja, Y.; Lazkoz, R.; Melchior, P.; Meneghetti, M.; Merten, J.; Ogaz, S.; Umetsu, K.

2013-11-01

403

Photometric and spectroscopic properties of Type II-P supernovae  

NASA Astrophysics Data System (ADS)

We study a sample of 23 Type II plateau supernovae (SNe II-P), all observed with the same set of instruments. Analysis of their photometric evolution confirms that their typical plateau duration is 100 d with little scatter, showing a tendency to get shorter for more energetic SNe. We examine the claimed correlation between the luminosity and the rise time from explosion to plateau. We analyse their spectra, measuring typical ejecta velocities, and confirm that they follow a well-behaved power-law decline. We find indications of high-velocity material in the spectra of six of our SNe. We test different dust-extinction correction methods by asking the following - does the uniformity of the sample increase after the application of a given method? A reasonably behaved underlying distribution should become tighter after correction. No method we tested made a significant improvement.

Faran, T.; Poznanski, D.; Filippenko, A. V.; Chornock, R.; Foley, R. J.; Ganeshalingam, M.; Leonard, D. C.; Li, W.; Modjaz, M.; Nakar, E.; Serduke, F. J. D.; Silverman, J. M.

2014-07-01

404

The photometric properties of the HST astrometer Fine Guidance Sensor  

NASA Technical Reports Server (NTRS)

This paper presents the results of the photometric calibration of the F583W filter in the astrometer Fine Guidance Sensor on the Hubble Space Telescope. Dozens of observations of the 9.58 mag Fine Guidance Sensor (FGS) transfer mode reference star Upgren 69 (in the cluster NGC 188) have been utilized to verify the consistency and demonstrate the temporal stability of the photomultipliers. The measurements which provided the material for a transformation from the FGS instrumental system to the Johnson V magnitude consisted of the extensive position mode observations performed during the Optical Field Angle Distortion calibration. A total of 588 measurements of 92 stars in the galactic cluster M35 were performed. Johnson V band photometry with a precision (i.e., random errors) of plus or minus 0.05 mag is available with an accuracy (i.e., systematic errors) of 0.05 mag over 2 yr.

Bucciarelli, B.; Holfeltz, S. T.; Lattanzi, M. G.; Taff, L. G.; Vener-Saavedra, P. C.

1994-01-01

405

Photometrical Research of GSS ?INTELSAT 10-02?  

NASA Astrophysics Data System (ADS)

On example of the studies the obtained coordinate and photometrical data GSS ?Intelsat 10-02? is shown as possible surveillance with the help of ground-based optical facilities dynamic state satellite and his behaviors on orbit. The analysis of variation character of the light curves in B,V,R filters, time intervals between the flashes, the color indexes variation shows that the systems of stabilization of the platform, the transceiving antennas and the solar panels worked in operating normal mode during the dates of observation. The solar panels orientation relative to the Sun maintains well enough, rotated practically along the equtor plane tracking the Sun's path (the Earth's rotation). Orientation to axis of the rotation of the platform practically remains to be unchanged to direction on the centre of the masses of the Earth.

Sukhov, P. P.; Karpenko, G. F.; Epishev, V. P.; Motrunych, I. I.

406

Photometric observations of local rocket-atmosphere interactions  

NASA Astrophysics Data System (ADS)

Photometric measurements from rocket flights which recorded a strong foreign luminance in the altitude region between 90 and 130 km are reported. From one Nike-Orion rocket the luminance appeared on both up-leg and down-leg; from a series of Petrel rockets the luminance was apparent only on the down-leg. The data suggest that the luminance may be distributed mainly in the wake region along the rocket trajectory. The luminance is believed to be due to a local interaction between the rocket and the atmosphere although the precise nature of the interaction is unknown. It was measured at wavelengths ranging from 275 nm to 1.61 microns and may be caused by a combination of reactions.

Greer, R. G. H.; Murtagh, D. P.; Witt, G.; Stegman, J.

1983-06-01

407

Fifth image and photometric variability in 2237 + 0305 ('Einstein Cross')  

SciTech Connect

The paper describes the morphological and photometric characteristics of the gravitational mirage 2237 + 0305, obtained by combining CCD frames in R and I taken with HRCam at the CFHT in a 0.4 arcsec (FWHM) observation on August 23, 1990. High S/N images of the 2237 + 0305 provided precise positions and relative magnitudes for the four brighter components and for the galaxy core, and new information on the light distribution in the lensing galaxy core was obtained. Compared with Yee's (1988) photometry, the present data show components B brighter by 0.25 mag and C fainter by 0.15 mag, while the brightness of A and D and the colors of all four images are unchanged. Possible reason for the variability trends of the four components are discussed. 19 refs.

Racine, R. (Observatoire du Mont Megantic (Canada) Montreal, Universite, Montreal (Canada) Canada-France-Hawaii Telescope Corp., Kamuela, HI (United States))

1991-08-01

408

Photometric characterization of the CIG sample (Durbala+, 2008)  

NASA Astrophysics Data System (ADS)

We perform a detailed photometric analysis (bulge-disc-bar decomposition and Concentration-Asymmetry-Clumpiness (CAS) parametrization) for a well-defined sample of isolated galaxies, extracted from the Catalog of Isolated Galaxies and reevaluated morphologically in the context of the Analysis of the interstellar Medium of Isolated GAlaxies project. We focus on Sb-Sc morphological types, as they are the most representative population among the isolated spiral galaxies. Our analysis yields a large number of important galactic parameters and various correlation plots are used to seek relationships that might shed light on the processes involved in determining those parameters. Assuming that the bulge Sersic index and/or bulge/total luminosity ratios are reasonable diagnostics for pseudo- versus classical bulges, we conclude that the majority of late-type isolated disc galaxies likely host pseudo-bulges rather than classical bulges. (4 data files).

Durbala, A.; Sulentic, J. W.; Buta, R.; Verdes-Montenegro, L.

2013-11-01

409

Photometric observation of the transiting exoplanet WASP-1b  

NASA Astrophysics Data System (ADS)

The extra-solar planet WASP-1b, discovered by SuperWASP consortium in 2006, was observed through R filter using the 1-meter telescope with CCD camera at Yunnan Observatory on November 11, 2006. The systematic errors in photometric data were reduced by means of Tamuz et al. (2005) and Collier Cameron et al. (2006)'s algorithms. In order to estimate the parameters of the system, the MCMC (Markov Chain Monte Carlo) analysis is applied to fit the observed light curve. The following parameters of the system are derived: Rp=1.44RJ, Mp=0.88MJ, R*=1.52R, a=0.0396AU. The new parameters of the planet imply its low density, which agrees to the previous results.

Wang, Xiao-bin; Collier Cameron, Andrew; Gu, Sheng-hong; Zhang, Li-yun

2008-05-01

410

A photometric study of the contact binary AZ Virginis  

NASA Astrophysics Data System (ADS)

New light curves and photometric solutions of the contact binary AZ Vir are presented in this paper. The light curves appear to exhibit a typical O'Connell effect, with Maximum I being 0.021 mag (V) and 0.023 mag (B) brighter than Maximum II, respectively. From the observations, six times of minimum light were determined and from the present times of minimum light and those collected from the references, the light elements of the system were improved. The light curves were analyzed by means of the Wilson-Devinney program. The results suggest that AZ Vir is a W-subtype contact binary with a mass ratio of q = 0.623(2). The asymmetry of the light curves is explained by star spot models.

Liu, Q.; Yang, Y.

2007-02-01

411

Photometric approach to surface reconstruction of artist paintings  

NASA Astrophysics Data System (ADS)

We propose a method for surface reconstruction of artist paintings. In order to reproduce the appearance of a painting, including color, surface texture, and glossiness, it is essential to acquire the pixel-wise light reflection property and orientation of the surface and render an image under an arbitrary lighting condition. A photometric approach is used to estimate bidirectional reflectance distribution functions (BRDFs) and surface normals from a set of images photographed by a fixed camera with sparsely distributed point light sources. A robust and computationally less expensive nonlinear optimization algorithm is proposed that optimizes the small number of parameters to simultaneously determine all of the specular BRDF, diffuse albedo, and surface normal. The proposed method can be applied to moderately glossy surfaces without separating captured images into diffuse and specular reflections beforehand. Experiments were conducted using oil paintings with different surface glossiness. The effectiveness of the proposed method is validated by comparing captured and rendered images.

Hasegawa, Takayuki; Tsumura, Norimichi; Nakaguchi, Toshiya; Iino, Koichi

2011-01-01

412

Carbon Stars In Andromeda. II. Demographics and Photometric Properties  

NASA Astrophysics Data System (ADS)

This is the second of two talks about a sample of newly-discovered carbon stars in the Andromeda galaxy (M31). As explained in the first talk, these stars were identified on the basis of their spectroscopic characteristics using Keck/DEIMOS spectra obtained as part of the Spectroscopic and Photometric Landscape of Andromeda's Stellar Halo (SPLASH) survey. We explore the physical properties of strong and weak carbon stars using photometric data from a Hubble Space Telescope Multi-Cycle Treasury program: Panchromatic Hubble Andromeda Treasury (PHAT). The PHAT data set includes deep photometry in six filters: two in the ultraviolet, two in the optical, and two in the near infrared. The carbon stars appear to be in the asymptotic giant branch stage of their evolution as evidenced by the fact that they lie above the tip of the red giant branch and are cleanly separated from normal (i.e., oxygen-rich) giants in color-magnitude diagrams. We study the spatial distribution of carbon stars in M31 and use kinematics to determine whether they belong to M31's thin disk, thick disk, or spheroid. These carbon stars serve as highly visible tracers of the intermediate-mass, intermediate-age stellar population in M31; they are important markers in the study of the star-formation history of the galaxy. This research was part of the SPLASH and PHAT collaboration. We are grateful to the National Science Foundation and NASA for funding support. AN's participation was under the auspices of UCSC's Science Internship Program.

Guhathakurta, Puragra; Hamren, K.; Dorman, C.; Toloba, E.; Seth, A.; Dalcanton, J.; Nayak, A.; PHAT Collaboration; SPLASH Collaboration

2014-01-01

413

Photometric study of the major satellites of Uranus  

NASA Astrophysics Data System (ADS)

In this paper, we analyze the results of ground-based and space-born photometric observations of the major satellites of Uranus—Miranda, Ariel, Umbriel, Titania, and Oberon. All sets of photometric observations of the satellites available in the literature were examined for uniformity and systematic differences and summarized to a unified set by wavelength ranging from 0.25 to 2.4 ?m. This set covers the interval of phase angles from 0.034° to 35°. The compound phase curves of brightness of the satellites in the spectral bands at 0.25, 0.41, 0.48, 0.56, 0.75, 0.91, 1.4, and 1.8 ?m, which include a pronounced opposition surge and linear part, were constructed. For each satellite, the geometric albedo was found in different spectral bands taking into account the brightness opposition effect, and its spectral dependence was studied. It has been shown that the reflectance of the satellites linearly depends on the wavelength at different phase angles, but has different spectral gradients. The parameters of the phase functions of brightness, including the amplitude and the angular width of the brightness opposition surge, the phase coefficient, and the phase angle at which the nonlinear increase in brightness starts, were determined and their dependences on wavelength and geometric albedo were analyzed. Our investigations show that, in their optical properties, the satellites Miranda and Ariel, Titania and Oberon, and Umbriel present three types of surfaces. The observed parameters of the brightness opposition effect for the Uranian satellites, some ice satellites of Jupiter and Saturn, and the E-and S-type asteroids are analyzed and compared within the framework of the coherent backscattering and mutual shadowing mechanisms.

Avramchuk, V. V.; Rosenbush, V. K.; Bul'Ba, T. P.

2007-06-01

414

Strömgren photometric survey in the Galactic anticenter direction  

NASA Astrophysics Data System (ADS)

Aims: The main purpose is to map the radial variation of the stellar space density for the young stellar population in the Galactic anticenter direction in order to understand the structure and location of the Perseus spiral arm. Methods: A uvbyH? Strömgren photometric survey covering 16 deg2 in the anticenter direction was carried out using the Wide Field Camera at the Isaac Newton Telescope. This is the natural photometric system for identifying young stars and obtaining accurate estimates of individual distances and ages. The calibration to the standard system was undertaken using open clusters. Results: We present a main catalog of 35 974 stars with all Strömgren indexes and a more extended one with 96 980 stars with partial data. The central 8 deg2 have a limiting magnitude of V ~ 17m, while the outer region reaches V ~ 15.m5. These large samples will permit us to analyze the stellar surface density variation associated to the Perseus arm also to study the properties of the stellar component and the interstellar extinction in the anticenter direction. Final catalog and catalog with individual measurements are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/549/A78Based on observations made with the Isaac Newton Telescope operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias.

Monguió, M.; Figueras, F.; Grosbøl, P.

2013-01-01

415

Flame photometric detector for thin-layer chromatography.  

PubMed

A new flame photometric detector for thin-layer chromatography (TLC) was studied to determine sulfur and phosphorus containing compounds in materials with a high boiling point. The detector was integrated with a flame ionization detector into the Iatroscan TLC-flame ionization detection analyzer. The principle of the detector is based on the photometric detection of flame emission of heteroatom in a hydrogen-air flame. The emission spectra of sulfur and phosphorus were measured using dibenzothiophene (DT) and phosphoric acid as source materials. Interference filters of 394 and 526 nm were chosen for spectral isolation of the sulfur and phosphorus emissions. The effects of variation in air flow-rate and scan speed as related to both sulfur and phosphorus compounds were studied in order to define optimum detection conditions. The best result for the detection of DT as a sulfur compound was obtained under combined hydrogen and air flow-rates of 160 and 500 ml/min, respectively, with a scan speed of 30 s/rod. The response to DT was linear in the range of 0.25-4 microg. On the other hand, the most suitable conditions for detecting phosphatidylcholine (PC) as a phosphorus compound were combined hydrogen and air flow-rates of 160 and 1500 ml/min, respectively, with a scan speed of 40 s/rod. The response to PC was linear in the range of 0.25-16 microg. Application of the instrument with selective detection of sulfur and phosphorus compounds was demonstrated using heavy oils and human serum lipids. PMID:12437173

Ogasawara, Minoru; Tsuruta, Kyoko; Arao, Shinsuke

2002-10-11

416

The photometric detection of known sun occluding orbital debris  

NASA Astrophysics Data System (ADS)

In this research, discrete, digital, Sun transit images are used for the photometric detection of the shadows of Sun occluding satellites. A theoretical pixel occlusion ratio is developed for use in the detection and the occluding area determination of satellites and orbital debris, traveling over known, or predicted, spatial temporal paths during transit. To verify the occluding area determination of a large satellite, a recorded transit of the International Space Station is analyzed. Also an experimental system, funded by a Beverly Sears Grant and a Sigma-Xi Grant-In-Aid of Research, consisting of a Meade ETX-90 telescope, and a Lumenera LU-075 camera is constructed to detect satellites and orbital debris in solar transits. The photometrically measured total occluding area of the Terra EOS-AM1 satellite, recorded in two separate transits, is shown to be consistent with the predicted occluding area of the satellite shadow. Further investigated is the theoretical resolution limit of this detection, as the occluding shadow becomes much smaller than a pixel area. The central limit theorem is used to approximate the maximum detection statistic, which can be achieved when integrating a matched spatial temporal path, containing the moving shadow. This detection statistic is predicted to be a function of the pixel occlusion ratio, the design parameters of the spatial temporal path, and the approximated Poisson variance of the photon count in each pixel. When the measured detection statistics of the two recorded transits are compared with the prediction model, the measurements agree with half the predicted value. This experimental error is largely attributed to filter mismatch in the spatial temporal path, and a spatial temporal variance in the recorded Sun transit images, which is larger than predicted by theory. These experimental verifications of the proposed theory are used to extrapolate the general limitations and capabilities of a system designed to detect Sun occluding orbital debris. In particular, the potential resolution capability of a system designed to detect smaller orbital debris is theorized.

Poller, Brian J.

2009-06-01

417

Miniature photometric stereo system for textile surface structure reconstruction  

NASA Astrophysics Data System (ADS)

In this work a miniature photometric stereo system is presented, targeting the three-dimensional structural reconstruction of various fabric types. This is a supportive module to a robot system, attempting to solve the well known "laundry problem". The miniature device has been designed for mounting onto the robot gripper. It is composed of a low-cost off-the-shelf camera, operating in macro mode, and eight light emitting diodes. The synchronization between image acquisition and lighting direction is controlled by an Arduino Nano board and software triggering. The ambient light has been addressed by a cylindrical enclosure. The direction of illumination is recovered by locating the reflection or the brightest point on a mirror sphere, while a flatfielding process compensates for the non-uniform illumination. For the evaluation of this prototype, the classical photometric stereo methodology has been used. The preliminary results on a large number of textiles are very promising for the successful integration of the miniature module to the robot system. The required interaction with the robot is implemented through the estimation of the Brenner's focus measure. This metric successfully assesses the focus quality with reduced time requirements in comparison to other well accepted focus metrics. Besides the targeting application, the small size of the developed system makes it a very promising candidate for applications with space restrictions, like the quality control in industrial production lines or object recognition based on structural information and in applications where easiness in operation and light-weight are required, like those in the Biomedical field, and especially in dermatology.

Gorpas, Dimitris; Kampouris, Christos; Malassiotis, Sotiris

2013-04-01

418

New Asteroid Shape Models Derived from the Lowell Photometric Database  

NASA Astrophysics Data System (ADS)

Asteroid shapes and spin states can be derived from their disk-integrated sparse-in-time photometry by the lightcurve inversion method. A huge amount of sparse photometry is provided by current all-sky surveys. However, the data from surveys suffer from large random and systematic errors. Oszkiewicz et al. (2011, JQSRT 112, 1919) partly removed the systematic trends in the photometry reported to the MPC and created the so-called 'Lowell photometric database'. The database consists of re-calibrated photometry for about 500,000 asteroids, with typically hundreds of brightness measurements per object. Bowell et al. (M&PS, submitted) used this database to analyze brightness variations with ecliptic longitude and estimated spin-axis longitudes for about 350,000 asteroids. In our work, we processed data for the first 10,000 numbered asteroids with the lightcurve inversion method (Kaasalainen et al., 2001, Icarus 153,37) using an enormous computational power of Asteroids@home (http://asteroidsathome.net) - a distributed computing project built on the BOINC platform. More than 10,000 users have joined the project and their computers were used for the time-consuming search for the sidereal rotation period in the sparse data. Although the photometric accuracy of the Lowell data is low 0.2 mag), we were able to find unique models for several hundred asteroids. We will present the first results based on the statistical analysis of the sample (distribution of spin vectors, for example) and we will also discuss the relevance of our approach to Gaia, LSST, ATLAS, and other future sources of asteroid photometry with sparse sampling.

Durech, Josef; Hanus, J.; Vanco, R.; Oszkiewicz, D.; Bowell, E.

2013-10-01

419

Simultaneous Photometric and Spectroscopic Observations of Young Solar Analogs  

NASA Astrophysics Data System (ADS)

This poster will present some preliminary results, focusing on the relationship between chromospheric activity level and stellar brightness, from our long-term monitoring campaign conducting simultaneous spectroscopic and photometric observations of young stellar analogs (YSAs). Since 2007 we have been conducting spectroscopic monitoring of the Ca II H & K lines for a sample of 31 YSAs in order to better understand their activity cycles and variations, as well as the effects of young stars on their solar systems. The targets cover the spectral range of stars most likely to contain Earth analogs, F8-K2, and a broad enough range of ages, 0.3 Gyr - 1.5 Gyr, to investigate how activity level changes with stellar age. These studies are already showing possible evidence for activity cycles, large variations in starspot activity, and flaring events. In order to obtain a more complete picture of the nature of the stars' activity and examine the correlations between stellar brightness and chromospheric activity, we recently began simultaneous photometric observations of the stars in Johnson B, V and R. Some stars, such as the Sun, show a positive correlation with brightness and activity level. Yet the Lowell Observatory SSS project showed that many G0-G2 type YSAs show a negative correlation. Of particular interest for our project is the determination of which stars show either a positive or negative correlation and characterizing how this changes with stellar age. Results from the first season of observations are presented here. Starting this year we will be adding two new instruments to provide improved temporal coverage and additional data in Stromgren v and H?. Support provided by the NSF.

Saken, Jon M.; Gray, R. O.; Corbally, C. J.

2012-05-01

420

Determination of the metal complexing capacity of aqueous solutions containing ligands by titration in the presence of complexing resins  

Microsoft Academic Search

The feasibility of ligand titrations with metal ions using complexing resins as sorbing solids is evaluated. The resins considered were the iminodiacetic resin Chelex 100, the carboxilic resin Amberlite CG50, and the anion exchange resin AG1X8, whose sorbing properties for aluminium(III) and copper(II) were known from previous investigations. Synthetical solutions containing known concentrations of ligands, EDTA and IDA were titrated

Maria Pesavento; Giancarla Alberti; Antonella Profumo

2000-01-01

421

Diagnostic procedures as a guide for the treatment of severe rhesus disease  

Microsoft Academic Search

The severity of fetal erythroblastosis is usually evaluated by the study of antibody titres, analysis of amniotic fluid and more recently by analysis of the antibody nitrogen content. The development of these latter procedures was prompted by the inadequacies of the antibody titration. Severe involvement may be associated with a low titre and indeed a rise in titre may occur

Thomas J. Degnan; Shirley Karasik

1970-01-01

422

On Hapke photometric model predictions on reflectance of closely packed particulate surfaces  

NASA Astrophysics Data System (ADS)

In a recent paper Hapke et al. (Hapke, B., Shepard, M., Nelson, R., Smythe, W., Piatek, J. [2009]. Icarus 199, 210-218) performed bi-directional reflectance measurements on closely-packed particulate surfaces of micrometer-sized particles and compared these with both the Hapke IMSA photometric model, and a numerical radiative transfer algorithm, the MDYZ (Mishchenko, M., Dlugach, J., Yanovitskij, E., Zakharova, N. [1999a]. J. Quant. Spectrosc. Radiat. Trans. 63, 409-432). To account for the effects of close packing, Hapke et al. applied a diffraction truncation scheme to remove the diffraction spike and supplied the renormalized single scattering phase function to the IMSA. They found that the IMSA prediction is a better match with measurement than that of MDYZ. In this work we demonstrate that the diffraction truncation procedure outlined by Hapke et al. contains an error. By following Hapke et al.'s intended truncation scheme, we have found that the IMSA model is not sufficiently anisotropic to describe the reflectance pattern of measurements on surface reflectance of closely packed large spherical particles.

Zhang, Hao; Voss, Kenneth J.

2011-09-01

423

The CCD photometric study of the newly identified RS CVn binary star V1034 Hercules  

NASA Astrophysics Data System (ADS)

This paper presents a new CCD Bessell VRcIc light curves and photometric analysis of the newly discovered RS CVn type eclipsing binary star V1034 Her. The light curves were obtained at the Çanakkale Onsekiz Mart University Observatory in 2006. Variations of the orbital period of the system were firstly studied. The ( O - C) diagram with a low range of observing time of about 20 years shows an upward parabola, which indicates a secular increase in the orbital period of the system. The light curves are generally those of detached eclipsing binaries; however, there are large asymmetries between maxima. The VRcIc light curves were analysed with two different fitting procedures: Wilson-Devinney method supplemented with a Monte Carlo type algorithm and Information Limit Optimization Technique (ILOT). Our general results find V1034 Her. as a well detached system, in which the components are filling ˜65% of their Roche lobes. Light curve asymmetries of the system are explained in terms of large dark starspots on the primary component. The primary star shows a long-lived spot distribution with active longitudes in the same hemisphere.

Dog?ru, D.; Erdem, A.; Dog?ru, S. S.

2009-11-01

424

Measurement of the photometric and spectral BRDF of small Canadian satellites in a controlled environment  

NASA Astrophysics Data System (ADS)

Measuring a satellite’s bidirectional reflection distribution function (BRDF) before and after launch can yield significant information relevant to the exploitation of remote photometric and spectrometric observations for Space Situational Awareness (SSA). There are three Canadian technology demonstration space missions, consisting of four small spacecraft representing three very different small satellite designs, which are scheduled to be launched between 2012 and 2013. These are the NEOSSat, CanX-4/CanX-5, and M3MSat spacecraft and all of these space missions have been partially funded by Defence R&D Canada (DRDC). They will each provide an opportunity to collect BRDF measurements from this class of satellites in a controlled laboratory environment before their launch and to then compare these data to remote observations. Given that the measurement of a spacecraft’s BRDF had never been attempted in Canada, it was deemed critical to develop and test a characterization procedure before gaining access to a real spacecraft. Accordingly, the first characterization experiment was conducted using an engineering model (EM) of the CanX-1 nanosatellite. All of the experimental objectives were successfully achieved and the experiment paved the way for the characterization of the NEOSSat microsatellite that is expected to be launched in early 2012. This paper will describe the spacecraft characterization methodology that was adopted for the CanX-1 EM and will present selected results from the experiments. The paper will conclude with a brief description of the NEOSSat characterization experiment.

Bedard, D.; Levesque, M.; Wallace, B.

2011-09-01

425

Humic substance charge determination by titration with a flexible cationic polyelectrolyte  

NASA Astrophysics Data System (ADS)

The anionic charge of humic substances (HS) plays a major role in the interaction of HS with other components. Therefore, the potential of the polyelectrolyte titration technique to obtain the charge density of HS in simple 1-1 electrolyte solutions has been investigated. Titrations are carried out with an automatic titrator combined with the "Mütek particle charge detector" which allows determination of the Mütek potential and the pH as a function of the added amount of titrant which is a solution of poly-diallyldimethylammonium chloride (polyDADMAC), a cationic strong polyelectrolyte. When the Mütek potential reverses its sign the iso-electric point (IEP) of the polyDADMAC-HS complex is reached. The polyDADMAC/HS mass ratio at the IEP gives information on the HS charge density and from the pH changes in solution an estimate of the charge regulation in the HS-polyDADMAC complex can be obtained. In general, for polyDADMAC-HS complexes an increase in the dissociation of the acid groups of HS is found (charge regulation). The charge regulation decreases with increasing concentration of 1-1 background electrolyte. Cation incorporation can be neglected at 1-1 electrolyte concentrations ? 1 mmol L -1 and a 1-1 stoichiometry exists between the polyDADMAC and HS charge. However, at these low salt concentrations the charge regulation is substantial. A detailed analysis of purified Aldrich humic acid (PAHA) at pH 5 and a range of KCl concentrations reveals that the anionic charge of PAHA in the complex increases at 5 mmol L -1 KCl by 30% and at 150 mmol L -1 KCl by 12%. On the other hand, increasing amounts of K + become incorporated in the complex: at 5 mmol L -1 KCl 5% and at 150 mmol L -1 KCl 24% of the PAHA charge is balanced by K +. By comparing at pH 5 the mass ratios polyDADMAC/PAHA in the complex at the IEP with the theoretical mass ratios of polyDADMAC/PAHA required to neutralize PAHA in the absence of charge regulation and K + incorporation, it is found that at 50 mmol L -1 KCl the extra negative charge due to the interaction between polyDADMAC and PAHA is just compensated by K + incorporation in the complex. Therefore, a pseudo 1-1 stoichiometry exists at about 50 mmol L -1 1-1 electrolyte concentration and only at this salt concentration polyDADMAC titrations and conventional proton titrations give identical results. Most likely this is also true for other HA samples and other pH values. For FA further study is required to reveal the conditions for which polyDADMAC and proton titrations give identical results.

Tan, Wen-Feng; Norde, Willem; Koopal, Luuk K.

2011-10-01

426

Keratorefractive procedures  

NASA Astrophysics Data System (ADS)

Two laser types are going to find a place in refractive surgery of the cornea: the excimer laser (193 nm) and mid-infrared YAG lasers, such as Ho:YAG (2.1 micrometers ) and Er:YAG (2.94 micrometers ). Whereas the excimer laser used for photorefractive keratectomy (PRK) and phototherapeutic keratectomy (PTK) is currently studied in clinical trials, Ho:YAG and Er:YAG lasers are still in the state of preclinical evaluation. For myopic corrections excimer laser PRK has shown to be safe and effective in the range up to -7.0 D. The results compare favorably with conventional procedures such as radial keratotomy. Complications are rare. Hyperopic and astigmatic corrections using the Ho:YAG laser (HOT) are effective, but safety and stability has yet to be proven. Er:YAG laser photoablation yields a healing response in animal eyes similar to the excimer laser.

Seiler, Theo

1991-11-01

427

On the indirect polyelectrolyte titration of cellulosic fibers. Conditions for charge stoichiometry and comparison with ESCA.  

PubMed

The effect of electrolyte (NaHCO3) concentration on the adsorption of poly-DADMAC (poly-diallyldimethylammonium chloride) onto cellulosic fibers with different charge profiles was investigated. Surface carboxymethylated fibers were obtained by grafting carboxymethyl cellulose (CMC) onto the fiber surface and bulk carboxymethylated fibers were obtained by reacting the fibers with monochloroacetic acid. It was shown that nonionic interactions do not exist between cellulose and poly-DADMAC, rather electrostatic interactions govern the adsorption. Charge stoichiometry prevails under electrolyte-free conditions, whereas surface charge overcompensation occurs at higher electrolyte concentrations. It was shown that charge stoichiometry prevails if the thickness of the electric double layer kappa(-1) was larger than the mean distance between the charges on the fiber surface, as predicted by polyelectrolyte adsorption theories, taking lateral correlation effects into account. In a second set of experiments the ESCA technique served to independently calibrate the polyelectrolyte titrations for determining the surface charge of cellulosic fibers. Various molecular masses of poly-DADMAC were adsorbed to carboxymethylated fibers having different charge profiles. The adsorption of low M(w) poly-DADMAC (7.0 x 10(3)), analyzed by polyelectrolyte titration, was about 10 times higher than that of the high M(w) poly-DADMAC (9.2 x 10(5)). Despite the difference in accessibility of these two polyelectrolytes to the fiber cell wall, ESCA surface analysis showed, as expected, only slight differences between the two polyelectrolytes. This gives strong credibility to the idea that surface charge content of cellulosic fibers can be analyzed by means of adsorption of a high-molecular-mass cationic polymer, i.e., by polyelectrolyte titration. PMID:16401137

Horvath, A Elisabet; Lindström, Tom; Laine, Janne

2006-01-17

428

Micellar acid-base potentiometric titrations of weak acidic and/or insoluble drugs.  

PubMed

The effect of various surfactants [the cationics cetyl trimethyl ammonium bromide (CTAB) and cetyl pyridinium chloride (CPC), the anionic sodium dodecyl sulphate (SDS), and the nonionic polysorbate 80 (Tween 80)] on the solubility and ionization constant of some sparingly soluble weak acids of pharmaceutical interest was studied. Benzoic acid (and its 3-methyl-, 3-nitro-, and 4-tert-butyl-derivatives), acetylsalicylic acid, naproxen and iopanoic acid were chosen as model examples. Precise and accurate acid-base titrations in micellar systems were made feasible using a microcomputer-controlled titrator. The response curve, response time and potential drift of the glass electrode in the micellar systems were examined. The cationics CTAB and CPC were found to increase considerably the ionization constant of the weak acids (delta pKa ranged from -0.21 to -3.57), while the anionic SDS showed negligible effect and the nonionic Tween 80 generally decreased the ionization constants. The solubility of the acids in aqueous micellar and acidified micellar solutions was studied spectrophotometrically and it was found increased in all cases. Acetylsalicylic acid, naproxen, benzoic acid and iopanoic acid could be easily determined in raw material and some of them in pharmaceutical preparations by direct titration in CTAB-micellar system instead of using the traditional non-aqueous or back titrimetry. Precisions of 0.3-4.3% RSD and good correlation with the official tedious methods were obtained. The interference study of some excipients showed that a preliminary test should be carried out before the assay of formulations. PMID:8466957

Gerakis, A M; Koupparis, M A; Efstathiou, C E

1993-01-01

429

Molecular Dynamics Simulation of the Titration of Polyoxocations in Aqueous Solution  

SciTech Connect

The aqueous complex ion Al30O8(OH)56(H2O)26 18+(Al30) has a variety of bridging and terminal amphoteric surface functional groups which deprotonate over a pH range of 4–7. Their relative degree of protonation is calculated here from a series of molecular dynamics simulations in what appear to be the first molecular dynamics simulations of an acidometric titration. In these simulations, a model M30O8(OH)56(H2O)26 18+ ion is embedded in aqueous solution and titrated with hydroxide ions in the presence of a charge-compensating background of perchlorate ions. Comparison with titration of a model M13O4(OH)24(H2O)12 7+ reveals that the M30 ion is more acidic than the M13 ion due to the presence of acidic nH2O functional groups. The higher acidities of the functional groups on the M30 ion appear to result from enhanced hydration. Metal–oxygen bond lengths are calculated for the ion in solution, an isolated ion in the gas phase, and in its crystalline hydrate sulfate salt. Gas-phase and crystalline bond lengths do not correlate well with those calculated in solution. The acidities do not relate in any simple way to the number of metals coordinating the surface functional group or the M-O bond length. Moreover, the calculated acidity in solution does not correlate with proton affinities calculated for the isolated ion in the absence of solvent. It is concluded that the search for simple indicators of structure–reactivity relationships at the level of individual reactive sites faces major limitations, unless specific information on the hydration states of the functional groups is available.

Rustad, James R.

2005-09-01

430

Non-damaging laser therapy of the macula: Titration algorithm and tissue response  

NASA Astrophysics Data System (ADS)

Retinal photocoagulation typically results in permanent scarring and scotomata, which limit its applicability to the macula, preclude treatments in the fovea, and restrict the retreatments. Non-damaging approaches to laser therapy have been tested in the past, but the lack of reliable titration and slow treatment paradigms limited their clinical use. We developed and tested a titration algorithm for sub-visible and non-damaging treatments of the retina with pulses sufficiently short to be used with pattern laser scanning. The algorithm based on Arrhenius model of tissue damage optimizes the power and duration for every energy level, relative to the threshold of lesion visibility established during titration (and defined as 100%). Experiments with pigmented rabbits established that lesions in the 50-75% energy range were invisible ophthalmoscopically, but detectable with Fluorescein Angiography and OCT, while at 30% energy there was only very minor damage to the RPE, which recovered within a few days. Patients with Diabetic Macular Edema (DME) and Central Serous Retinopathy (CSR) have been treated over the edematous areas at 30% energy, using 200?m spots with 0.25 diameter spacing. No signs of laser damage have been detected with any imaging modality. In CSR patients, subretinal fluid resolved within 45 days. In DME patients the edema decreased by approximately 150?m over 60 days. After 3-4 months some patients presented with recurrence of edema, and they responded well to retreatment with the same parameters, without any clinically visible damage. This pilot data indicates a possibility of effective and repeatable macular laser therapy below the tissue damage threshold.

Palanker, Daniel; Lavinsky, Daniel; Dalal, Roopa; Huie, Philip

2014-02-01

431

Automated high-pressure titration system with in situ infrared spectroscopic detection  

NASA Astrophysics Data System (ADS)

A fully automated titration system with infrared detection was developed for investigating interfacial chemistry at high pressures. The apparatus consists of a high-pressure fluid generation and delivery system coupled to a high-pressure cell with infrared optics. A manifold of electronically actuated valves is used to direct pressurized fluids into the cell. Precise reagent additions to the pressurized cell are made with calibrated tubing loops that are filled with reagent and placed in-line with the cell and a syringe pump. The cell's infrared optics facilitate both transmission and attenuated total reflection (ATR) measurements to monitor bulk-fluid composition and solid-surface phenomena such as adsorption, desorption, complexation, dissolution, and precipitation. Switching between the two measurement modes is accomplished with moveable mirrors that direct the light path of a Fourier transform infrared spectrometer into the cell along transmission or ATR light paths. The versatility of the high-pressure IR titration system was demonstrated with three case studies. First, we titrated water into supercritical CO2 (scCO2) to generate an infrared calibration curve and determine the solubility of water in CO2 at 50 °C and 90 bar. Next, we characterized the partitioning of water between a montmorillonite clay and scCO2 at 50 °C and 90 bar. Transmission-mode spectra were used to quantify changes in the clay's sorbed water concentration as a function of scCO2 hydration, and ATR measurements provided insights into competitive residency of water and CO2 on the clay surface and in the interlayer. Finally, we demonstrated how time-dependent studies can be conducted with the system by monitoring the carbonation reaction of forsterite (Mg2SiO4) in water-bearing scCO2 at 50 °C and 90 bar. Immediately after water dissolved in the scCO2, a thin film of adsorbed water formed on the mineral surface, and the film thickness increased with time as the forsterite began to dissolve. However, after approximately 2.5 h, the trend reversed, and a carbonate precipitate began to form on the forsterite surface, exposing dramatic chemical changes in the thin-water film. Collectively, these applications illustrate how the high-pressure IR titration system can provide molecular-level information about the interactions between variably wet scCO2 and minerals relevant to underground storage of CO2 (geologic carbon sequestration). The apparatus could also be utilized to study high-pressure interfacial chemistry in other areas such as catalysis, polymerization, food processing, and oil and gas recovery.

Thompson, Christopher J.; Martin, Paul F.; Chen, Jeffrey; Benezeth, Pascale; Schaef, Herbert T.; Rosso, Kevin M.; Felmy, Andrew R.; Loring, John S.

2014-04-01

432

Quantitation of Heme Oxygenase-1: Heme Titration Increases Yield of Purified Protein  

PubMed Central

Free heme binds to heme oxygenase as a prosthetic group and substrate in the conversion of heme to biliverdin, carbon monoxide, and free iron. Current methods for quantifying heme oxygenase-1 (HO-1) involve reconstitution of the enzyme with heme, followed by a hydroxyapatite column to remove the excess heme. As a result of the hydroxyapatite chromatography, there are significant losses of purified protein. We have developed a method which allows accurate quantitation of HO-1 using a heme titration and elimination of the final hydroxyapatite column, increasing the amount of purified protein.

Huber, Warren J.; Backes, Wayne L.

2008-01-01

433

Comparison of methods for isolation and titration of Crimean-Congo hemorrhagic fever virus.  

PubMed Central

The fluorescence focus assay and the plaque assay in CER cells were compared with mouse inoculation for the isolation and titration of Crimean-Congo hemorrhagic fever virus. The fluorescence focus assay and the plaque assay were of similar sensitivity, but both produced 10- to 100-fold lower titers than did mouse inoculation. For specimens from 26 Crimean-Congo hemorrhagic fever patients in South Africa, virus was isolated from 20 by mouse inoculation and from only 11 by cell culturing. Although cell cultures were less sensitive for the isolation of virus from clinical specimens, they produced diagnostic results much more rapidly.

Shepherd, A J; Swanepoel, R; Leman, P A; Shepherd, S P

1986-01-01

434

Automated high-pressure titration system with in situ infrared spectroscopic detection.  

PubMed

A fully automated titration system with infrared detection was developed for investigating interfacial chemistry at high pressures. The apparatus consists of a high-pressure fluid generation and delivery system coupled to a high-pressure cell with infrared optics. A manifold of electronically actuated valves is used to direct pressurized fluids into the cell. Precise reagent additions to the pressurized cell are made with calibrated tubing loops that are filled with reagent and placed in-line with the cell and a syringe pump. The cell's infrared optics facilitate both transmission and attenuated total reflection (ATR) measurements to monitor bulk-fluid composition and solid-surface phenomena such as adsorption, desorption, complexation, dissolution, and precipitation. Switching between the two measurement modes is accomplished with moveable mirrors that direct the light path of a Fourier transform infrared spectrometer into the cell along transmission or ATR light paths. The versatility of the high-pressure IR titration system was demonstrated with three case studies. First, we titrated water into supercritical CO2 (scCO2) to generate an infrared calibration curve and determine the solubility of water in CO2 at 50?°C and 90 bar. Next, we characterized the partitioning of water between a montmorillonite clay and scCO2 at 50?°C and 90 bar. Transmission-mode spectra were used to quantify changes in the clay's sorbed water concentration as a function of scCO2 hydration, and ATR measurements provided insights into competitive residency of water and CO2 on the clay surface and in the interlayer. Finally, we demonstrated how time-dependent studies can be conducted with the system by monitoring the carbonation reaction of forsterite (Mg2SiO4) in water-bearing scCO2 at 50?°C and 90 bar. Immediately after water dissolved in the scCO2, a thin film of adsorbed water formed on the mineral surface, and the film thickness increased with time as the forsterite began to dissolve. However, after approximately 2.5 h, the trend reversed, and a carbonate precipitate began to form on the forsterite surface, exposing dramatic chemical changes in the thin-water film. Collectively, these applications illustrate how the high-pressure IR titration system can provide molecular-level information about the interactions between variably wet scCO2 and minerals relevant to underground storage of CO2 (geologic carbon sequestration). The apparatus could also be utilized to study high-pressure interfacial chemistry in other areas such as catalysis, polymerization, food processing, and oil and gas recovery. PMID:24784630

Thompson, Christopher J; Martin, Paul F; Chen, Jeffrey; Benezeth, Pascale; Schaef, Herbert T; Rosso, Kevin M; Felmy, Andrew R; Loring, John S

2014-04-01

435

Combined ion selective electrode and fluorescence quenching detection for copper-dissolved organic matter titrations  

SciTech Connect

Copper-dissolved organic matter binding is observed for Black Lake, NC, fulvic acid by measuring free metal with a copper ion selective electrode (ISE) and the unbound organic ligand by fluorescence. The two detectors agree at low, aquatic levels of copper loading; a discrepancy at high copper concentrations may result from precipitation or inappropriate assumptions about the fluorescence technique. Complementary error properties of combined detection provide low-error titration data over a wider range of pH and pCu than either detector alone. Calibration by ISE is more reliable than curve fitting for relating fluorescence to bound copper concentrations. 24 references, 6 figures.

Cabaniss, S.E.; Shuman, M.S.

1986-02-01

436

PROPERTIES OF SATELLITE GALAXIES IN THE SDSS PHOTOMETRIC SURVEY: LUMINOSITIES, COLORS, AND PROJECTED NUMBER DENSITY PROFILES  

SciTech Connect

We analyze photometric data in the Sloan Digital Sky Survey Data Release 7 (SDSS-DR7) to infer statistical properties of faint satellites associated with isolated bright galaxies (M{sub r} < -20.5) in the redshift range 0.03 < z < 0.1. The mean projected radial number density profile shows an excess of companions in the photometric sample around the primaries, with approximately a power-law shape that extends up to {approx_equal} 700 kpc. Given this overdensity signal, a suitable background subtraction method is used to study the statistical properties of the population of bound satellites, down to magnitude M{sub r} = -14.5, in the projected radial distance range 100 < r{sub p} /kpc < 3(R{sub vir}). The maximum projected distance corresponds to the range 470-660 kpc for the different samples. We have also considered a color cut consistent with the observed colors of spectroscopic satellites in nearby galaxies so that distant redshifted galaxies do not dominate the statistics. We have tested the implementation of this background subtraction procedure using a mock catalog derived from the Millennium simulation semianalytic galaxy catalog based on a {Lambda} cold dark matter model. We find that the method is effective in reproducing the true projected radial satellite number density profile and luminosity distributions, providing confidence in the results derived from SDSS data. We find that the spatial extent of satellite systems is larger for bright, red primaries. Also, we find a larger spatial distribution of blue satellites. For the different samples analyzed, we derive the average number of satellites and their luminosity distributions down to M{sub r} = -14.5. The mean number of satellites depends very strongly on host luminosity. Bright primaries (M{sub r} < -21.5) host on average {approx}6 satellites with M{sub r} < -14.5. This number is reduced for primaries with lower luminosities (-21.5 < M{sub r} < -20.5) which have less than one satellite per host. We provide Schechter function fits to the luminosity distributions of satellite galaxies where the resulting faint-end slopes equal to 1.3 {+-} 0.2, consistent with the universal value. This shows that satellites of bright primaries lack an excess population of faint objects, in agreement with the results in the Milky Way and nearby galaxies.

Lares, M.; Lambas, D. G.; Dominguez, M. J. [Instituto de Astronomia Teorica y Experimental (CONICET-UNC), Observatorio Astronomico de Cordoba (UNC), Laprida 854, X5000BGR, Cordoba (Argentina)

2011-07-15

437

[Functional evaluation of erythrocytic antibodies by photometric detection of erythrophagocytosis in the monocyte monolayer assay].  

PubMed

In haemolytic disease of newborn (erythroblastosis fetalis) the in vivo behaviour of erythrocytic IgG antibodies is of particular significance. The monocyte monolayer assay (MMA), which determines by microscopy the number of erythrocytes phagocytosed by monocytes, is an important functional test for the qualitative assessment of erythrocytic IgG antibodies. We set up a photometric MMA and compared it with the microscopic MMA. In both tests we employed commercially available rhesus antibody sera and examined 8 sera of pregnant women with mild and severe courses of haemolytic disease of newborn by the photometric MMA. Good agreement was found between the microscopic and photometric MMA (r = 0.93). Over and above this the photometric MMA correlated with the course of haemolytic disease of newborn in 7 out of 8 cases (with one false-positive finding). The photometric technique permits rapid, sensitive and reproducible determination of erythrophagocytosis in microtitre plates. This method is based on the photometric detection of haemoglobin of phagocytosed erythrocytes via a peroxidase reaction. Standardised photometric MMA could in future be more widely applied especially in haemolytic disease of newborn for the functional characterisation of erythrocytic antibodies, the incidence of intra-assay and inter-assay errors being low. PMID:8766487

Cassens, U; Garritsen, H S; Sibrowski, W; Holzgreve, W

1996-06-01

438

A Photometric redshift galaxy catalog from the Red-Sequence Cluster Survey  

SciTech Connect

The Red-Sequence Cluster Survey (RCS) provides a large and deep photometric catalog of galaxies in the z' and R{sub c} bands for 90 square degrees of sky, and supplemental V and B data have been obtained for 33.6 deg{sup 2}. They compile a photometric redshift catalog from these 4-band data by utilizing the empirical quadratic polynomial photometric redshift fitting technique in combination with CNOC2 and GOODS/HDF-N redshift data. The training set includes 4924 spectral redshifts. The resulting catalog contains more than one million galaxies with photometric redshifts < 1.5 and R{sub c} < 24, giving an rms scatter {delta}({Delta}z) < 0.06 within the redshift range 0.2 < z < 0.5 and {sigma}({Delta}z) < 0.11 for galaxies at 0.0 < z < 1.5. They describe the empirical quadratic polynomial photometric redshift fitting technique which they use to determine the relation between red-shift and photometry. A kd-tree algorithm is used to divide up the sample to improve the accuracy of the catalog. They also present a method for estimating the photometric redshift error for individual galaxies. They show that the redshift distribution of the sample is in excellent agreement with smaller and much deeper photometric and spectroscopic redshift surveys.

Hsieh, Bau-Ching; /Taiwan, Natl. Central U. /Taipei, Inst. Astron. Astrophys.; Yee, H.K.C.; /Toronto U., Astron. Dept.; Lin, H.; /Fermilab; Gladders, M.D.; /Carnegie Inst. Observ.

2005-02-01

439

A Photometric Redshift Galaxy Catalog from the Red-Sequence Cluster Survey  

NASA Astrophysics Data System (ADS)

The Red-Sequence Cluster Survey (RCS) provides a large and deep photometric catalog of galaxies in the z' and Rc bands for 90 deg2 of sky, and supplemental V and B data have been obtained for 33.6 deg2. We compile a photometric redshift catalog from these four-band data by utilizing the empirical quadratic polynomial photometric redshift fitting technique in combination with CNOC2 and GOODS/HDF-N redshift data. The training set includes 4924 spectral redshifts. The resulting catalog contains more than one million galaxies with photometric redshifts <1.5 and Rc<24, giving an rms scatter ?(?z)<0.06 within the redshift range 0.2photometric redshift fitting technique that we use to determine the relation between redshift and photometry. A kd-tree algorithm is used to divide up our sample to improve the accuracy of our catalog. We also present a method for estimating the photometric redshift error for individual galaxies. We show that the redshift distribution of our sample is in excellent agreement with smaller and much deeper photometric and spectroscopic redshift surveys.

Hsieh, B. C.; Yee, H. K. C.; Lin, H.; Gladders, M. D.

2005-06-01

440

Improving the identification of high-z Herschel sources with position priors and optical/NIR and FIR/mm photometric redshifts  

NASA Astrophysics Data System (ADS)

We present preliminary results about the detection of high redshift (U)LIRGs in the Bullet cluster field by the PACS and SPIRE instruments within the Herschel Lensing Survey (HLS) Program. We describe in detail a photometric procedure designed to recover robust fluxes and deblend faint Herschel sources near the confusion noise. The method is based on the use of the positions of Spitzer/MIPS 24 ?m sources as priors. Our catalogs are able to reliably (5?) recover galaxies with fluxes above 6 and 10 mJy in the PACS 100 and 160 ?m channels, respectively, and 12 to 18 mJy in the SPIRE bands. We also obtain spectral energy distributions covering the optical through the far-infrared/millimeter spectral ranges of all the Herschel detected sources, and analyze them to obtain independent estimations of the photometric redshift based on either stellar population or dust emission models. We exemplify the potential of the combined use of Spitzer position priors plus independent optical and IR photometric redshifts to robustly assign optical/NIR counterparts to the sources detected by Herschel and other (sub-)mm instruments. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

Pérez-González, P. G.; Egami, E.; Rex, M.; Rawle, T. D.; Kneib, J.-P.; Richard, J.; Johansson, D.; Altieri, B.; Blain, A. W.; Bock, J. J.; Boone, F.; Bridge, C. R.; Chung, S. M.; Clément, B.; Clowe, D.; Combes, F.; Cuby, J.-G.; Dessauges-Zavadsky, M.; Dowell, C. D.; Espino-Briones, N.; Fadda, D.; Fiedler, A. K.; Gonzalez, A.; Horellou, C.; Ilbert, O.; Ivison, R. J.; Jauzac, M.; Lutz, D.; Pelló, R.; Pereira, M. J.; Rieke, G. H.; Rodighiero, G.; Schaerer, D.; Smith, G. P.; Valtchanov, I.; Walth, G. L.; van der Werf, P.; Werner, M. W.; Zemcov, M.

2010-07-01

441

The galaxy population of Abell 1367: photometric and spectroscopic data  

NASA Astrophysics Data System (ADS)

Aims: Photometric and spectroscopic observations of the galaxy population of the galaxy cluster Abell 1367 have been obtained, over a field of 34' × 90', covering the cluster centre out to a radius of ~2.2 Mpc. Optical broad- and narrow-band imaging was used to determine galaxy luminosities, diameters and morphologies, and to study current star formation activity of a sample of cluster galaxies. Near-infrared imaging was obtained to estimate integrated stellar masses, and to aid the determination of mean stellar ages and metallicities for the future investigation of the star formation history of those galaxies. Optical spectroscopic observations were also taken, to confirm cluster membership of galaxies in the sample through their recession velocities. Methods.U, B and R broad-band and H? narrow-band imaging observations were carried out using the Wide Field Camera (WFC) on the 2.5 m Isaac Newton Telescope on La Palma, covering the field described above. J and K near-infrared imaging was obtained using the Wide Field Camera (WFCAM) on the 3.8 m UK Infrared Telescope on Mauna Kea, covering a somewhat smaller field of 0.75 square degrees on the cluster centre. The spectroscopic observations were carried out using a multifibre spectrograph (WYFFOS) on the 4.2 m William Herschel Telecope on La Palma, over the same field as the optical imaging observations. Results: Our photometric data give optical and near-infrared isophotal magnitudes for 303 galaxies in our survey regions, down to stated diameter and B-band magnitude limits, determined within R24 isophotal diameters. Our spectroscopic data of 328 objects provide 84 galaxies with detections of emission and/or absorption lines. Combining these with published spectroscopic data gives 126 galaxies within our sample for which recession velocities are known. Of these, 72 galaxies are confirmed as cluster members of Abell 1367, 11 of which are identified in this study and 61 are reported in the literature. H? equivalent widths and fluxes are presented for all cluster galaxies with detected line emission. Conclusions: Spectroscopic and photometric data are presented for galaxies in the nearby cluster Abell 1367, as the first stage of a study of their stellar population and star formation properties. Based on observations made with the Isaac Newton Telescope and the William Herschel Telescope, operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias and the United Kingdom Infra-Red Telescope operated on Mauna Kea, Hawaii by the Joint Astronomy Centre.Tables 8-11 are also available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/527/A101

Kriwattanawong, W.; Moss, C.; James, P. A.; Carter, D.

2011-03-01

442

Efficacy and safety of early versus late titration of fixed-dose irbesartan/hydrochlorothiazide: ACTUAL study.  

PubMed

Hypertension management guidelines recommend titrating antihypertensive drugs stepwise every 4-6 weeks.We compared efficacy and safety of early versus late titration after 10 weeks' treatment with irbesartan/hydrochlorothiazide. Hypertensive patients uncontrolled on monotherapy were randomized into two groups. In the early titration group (E), patients received irbesartan/hydrochlorothiazide 150/12.5 mg for 2 weeks; uncontrolled patients were up-titrated to 300/25 mg at weeks 2 and 6. In the late titration group (L), patients received 150/12.5 mg for 6 weeks; uncontrolled patients were up-titrated to 300/25 mg at week 6 (W6). The change of mean systolic (SBP) and diastolic blood pressure (DBP) from baseline to week 10 (W10) were studied using a covariance analysis model. The percentage of controlled patients at W10 was compared between groups using Fisher's exact test. Of 833 patients enrolled from 14 countries, the intent-to-treat (ITT) population included 795 (mean age 58 +/- 12 years, female 60%, obesity 38%, diabetes 22%). AtW6, mean SBP decrease was: E - 28.8 mmHg vs L - 26.3 mmHg (p = 0.02). At W10, there was similar mean SBP decrease: E - 29.5 mmHg vs L- 31.0 mmHg (p = 0.14). The control rate at W10 was 58% (E) and 64% (L), p = 0.06. Serious adverse events were more frequent in E (2.5% vs 0.7%, p= 0.044). Both early and late titration regimens provide similar BP decrease and control rate. PMID:22352122

Girerd, Xavier; Rosenbaum, David; Aoun, Joseph

2011-12-01

443

Kepler Input Catalog: Photometric Calibration and Stellar Classification  

NASA Astrophysics Data System (ADS)

We describe the photometric calibration and stellar classification methods used by the Stellar Classification Project to produce the Kepler Input Catalog (KIC). The KIC is a catalog containing photometric and physical data for sources in the Kepler mission field of view; it is used by the mission to select optimal targets. Four of the visible-light (g, r, i, z) magnitudes used in the KIC are tied to Sloan Digital Sky Survey magnitudes; the fifth (D51) is an AB magnitude calibrated to be consistent with Castelli & Kurucz (CK) model atmosphere fluxes. We derived atmospheric extinction corrections from hourly observations of secondary standard fields within the Kepler field of view. For these filters and extinction estimates, repeatability of absolute photometry for stars brighter than magnitude 15 is typically 2%. We estimated stellar parameters {T eff, log (g), log (Z), E B - V } using Bayesian posterior probability maximization to match observed colors to CK stellar atmosphere models. We applied Bayesian priors describing the distribution of solar-neighborhood stars in the color-magnitude diagram, in log (Z), and in height above the galactic plane. Several comparisons with samples of stars classified by other means indicate that for 4500 K <=T eff <= 6500 K, our classifications are reliable within about ±200 K and 0.4 dex in log (g) for dwarfs, with somewhat larger log (g) uncertainties for giants. It is difficult to assess the reliability of our log (Z) estimates, but there is reason to suspect that it is poor, particularly at extreme T eff. Comparisons between the CK models and observed colors are generally satisfactory with some exceptions, notably for stars cooler than 4500 K. Of great importance for the Kepler mission, for T eff <= 5400 K, comparison with asteroseismic results shows that the distinction between main-sequence stars and giants is reliable with about 98% confidence. Larger errors in log (g) occur for warmer stars, for which our filter set provides inadequate gravity diagnostics. The KIC is available through the MAST data archive.

Brown, Timothy M.; Latham, David W.; Everett, Mark E.; Esquerdo, Gilbert A.

2011-10-01

444

Dust effects on photometric parameters in spirals (Pastrav+ 2013)  

NASA Astrophysics Data System (ADS)

The tables from appendix A (tablea*) list the corrections for projection effects on bulge- disk decomposition, the tables from appendix B (tableb*) list the corrections for the effects of dust on bulge-to-disk decomposition, while the tables from appendix C (tablec*) list the corrections for the effects of dust on single Sersic fits of galaxies containing a disk and a bulge. The corrections in Table A and B are given for the scalelength/effective radius, Sersic index and bulge-to disk ratio of disks and bulges. The corrections in table C are given for the effective radius of composite systems. The corrections are given as a function of inclination, central face-on optical depth in the B band taufB, and wavelength. The parameter space covered by this is as follows: taufB={0.1,0.3,0.5,1.0,2.0,4.0,8.0} wavelength (in Angstrom): 4430,5640,8090,12590,22000. The corrections are provided for photometric fits done with the following functions: i) exponential+Sersic functions for disk and bulge ii) variable index Sersic functions for both the disk and the bulge iii) single Sersic fits The corrections are provided for systems with exponential bulges (i.e. Sersic index fixed to unity) and de Vaucouleurs bulges. The corrections can be used together with the ones given in Pastrav et al. (2013, Cat. J/A+A/553/A80), using Eqs. 10 and 11 from Pastrav et al. (2013, Cat. J/A+A/553/A80). The photometric parameters for which corrections are listed are as follows: R - the exponential scalelength Reff - the effective radius nsers - the Sersic index B/D - bulge-to-disk ratio of the composite system To facilitate access to the information and to allow the corrections to be calculated for any inclination, the corrections are presented in the form of polynomial function fits. For all cases the fitted function is given by Eq. 16 of the paper. (70 data files).

Pastrav, B. A.; Popescu, C. C.; Tuffs, R. J.; Sansom, A. E.

2013-08-01

445

Predicting Fundamental Stellar Parameters From Photometric Light Curves  

NASA Astrophysics Data System (ADS)

We present a new machine-learning-based framework for the prediction of the fundamental stellar parameters, Teff, log g, and [Fe/H], based on the photometric light curves of variable stellar sources. The method was developed following a systematic spectroscopic survey of stellar variability. Variable sources were selected from repeated Sloan Digital Sky Survey (SDSS) observations of Stripe 82, and spectroscopic observations were obtained with Hectospec on the 6.5-m Multi-Mirror Telescope. In sum, spectra were obtained for ~9000 stellar variables (including ~3000 from the SDSS archive), for which we measured Teff, log g, and [Fe/H] using the Segue Stellar Parameters Pipeline (SSPP). Examining the full sample of ~67k variables in Stripe 82, we show that the vast majority of photometric variables are consistent with main-sequence stars, even after restricting the search to high galactic latitudes. From the spectroscopic sample we confirm that most of these stellar variables are G and K dwarfs, though there is a bias in the output of the SSPP that prevents the identification of M type variables. We are unable to identify the dominant source of variability for these stars, but eclipsing systems and/or star spots are the most likely explanation. We develop a machine-learning model that can determine Teff, log g, and [Fe/H] without obtaining a spectrum. Instead, the random-forest-regression model uses SDSS color information and light-curve features to infer stellar properties. We detail how the feature set is pruned and the model is optimized to produce final predictions of Teff, log g, and [Fe/H] with a typical scatter of 165 K, 0.42 dex, and 0.33 dex, respectively. We further show that for the subset of variables with at least 50 observations in the g band the typical scatter reduces to 75 K, 0.19 dex, and 0.16 dex, respectively. We consider these results an important step on the path to the efficient and optimal extraction of information from future time-domain experiments, such as the Large Survey Synoptic Telescope. We argue that this machine-learning framework, for which we outline future possible improvements, will enable the construction of the most detailed maps of the Milky Way ever created.

Miller, Adam; Richards, J.; Bloom, J. S.; on behalf of a larger Team

2014-01-01

446

Spectrophotometric titration of bimetallic metal cation binding in polyamido(amine) dendrimer templates.  

PubMed

Spectrophotometric titration and a binding isotherm were used to accurately assess the loading capacity of generation four polyamido(amine) (PAMAM) dendrimer templates with terminal alcohol groups (G4-OH). Preparation of bimetallic G4-OH dendrimer-encapsulated metal nanoclusters (DENs) necessitates knowledge of the precise metal-ion binding capacity. The binding of metal ions such as Pt(2+) and Pd(2+) has proven difficult to assess via UV-vis spectroscopy because the absorbance shifts associated