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1

Determination of lanthanum by flame photometric titration.  

PubMed

The flame emission of lanthanum at 560 mmu decreases linearly with phosphate concentration until a 1:1 molar ratio is reached, and then remains practically constant. Lanthanum can be titrated with phosphate, the equivalence point being detected from the change in emission intensity. Errors due to consumption of solution by the atomizer can be kept low by using short spraying times and low galvanometer damping. The average error is about -1% for 0.1M solutions and less than -5% for 0.01M. The method gives good results in the presence of titanium(III), zirconium, thorium and aluminium but cerium(III) and yttrium seriously interfere. PMID:18960392

Svehla, G; Slevin, P J

1968-09-01

2

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

3

Determination of polyhexamethylene biguanide hydrochloride using photometric colloidal titration with crystal violet as a color indicator.  

PubMed

A solution of polyhexamethylene biguanide hydrochloride (PHMB-HCl) was titrated with a standard solution of potassium poly(vinyl sulfate) (PVSK) using crystal violet (CV) as an photometric indicator cation. The end point was detected by a sharp absorbance change due to an abrupt decrease in the concentration of CV. A linear relationship between the concentration of PHMB-HCl and the end-point volume of the titrant existed in the concentration range from 2 to 10 × 10(-6) eq mol L(-1). Back-titration was based on adding an excess amount of PVSK to a sample solution containing CV, which was titrated with a standard solution of poly(diallyldimethylammonium chloride) (PDADMAC). The calibration curve of the PHMB-HCl concentration to the end point volume of the titrant was also linear in the concentration range from 2 to 8 × 10(-6) eq mol L(-1). Both photometric titrations were applied to the determination of PHMB-HCl in a few contact-lens detergents. Back-titration showed a clear end point, but direct titration showed an unclear end point. The results of the back-titration of PHMB-HCl were compared with the content registered in its labels. PMID:21828919

Masadome, Takashi; Miyanishi, Takaaki; Watanabe, Keita; Ueda, Hiroshi; Hattori, Toshiaki

2011-01-01

4

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

5

Scopolamine Effects Under a Titrating-Delayed-Nonmatching-to-Position Procedure  

ERIC Educational Resources Information Center

In a study of working memory, the performance of rats under titrating-delayed-nonmatching- to-position (TDNMTP) procedures was examined. Overall accuracy and the number of trials completed were inversely related to titration value, whereas the highest delay attained was directly related to titration value. When given intraperitoneally,…

Porritt, M.; Poling, A.

2008-01-01

6

A modified Benesi titration procedure useful to quantify the Lewis and Bronsted sites of solid acids  

SciTech Connect

The Benesi method of acid center titration has been modified using dry box techniques so that only 1 g of sample is required to determine the strength distribution of a given sample. Addition of an excess of sterically hindered pyridine to a second 1-g sample, and subsequent titration with n-butylamine using dry box procedures, also allows the strong Lewis acid sites to be quantitatively assessed. By combination of this titration procedure with the modified Benesi procedure the number of Bronsted sites could be determined accurately. Four classes of solid acids were investigated: {gamma}-alumina, high-silica silica-alumina, fluorided alumina, and WO{sub 3} on Al{sub 2}O{sub 3}.

Murrell, L.L.; Dispenziere, N.C. Jr. (Exxon Research and Engineering Co., Annandale, NJ (USA))

1989-05-01

7

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

8

An exact definition of total alkalinity and a procedure for the estimation of alkalinity and total inorganic carbon from titration data  

NASA Astrophysics Data System (ADS)

The total (or titration) alkalinity of a natural water sample can be regarded as a measure of the proton deficit of the solution relative to an arbitrarily defined zero level of protons. The problem of unambiguously incorporating any particular acid-base system into the definition of alkalinity is thus the one of deciding which form to specify as the zero level of protons, and it is proposed that it be defined so that acids with a dissociation constant K > 10-4·5 (at 25°C and zero ionic strength) are considered as proton donors, whilst those bases formed from weak acids with K ? 10-4·5 are cosidered proton acceptors. A non-linear least squares procedure is suggested in order to estimate the total alkalinity (AT) and total inorganic carbon (CT) of a seawater sample from potentiometric titration data. The approach offers a significant conceptual improvement over the currently used refined Gran functions. In addition, an estimate of the statistical uncertainty of the estimated values of AT and CT is available. As it unnecessary to titrate beyond the alkalinity equivalence point, it may also be possible to speed up the titrations.

Dickson, A. G.

1981-06-01

9

Thermodynamics study of the dimerization equilibria of rhodamine B and 6G in different ionic strengths by photometric titration and chemometrics method  

NASA Astrophysics Data System (ADS)

The dimerization constants of rhodamine B and 6G have been determined by studying the dependence of their absorption spectra on the temperature in the range 20-80 °C at different total concentrations of rhodamine B (5.89 × 10 -6 to 2.36 × 10 -4 M) and rhodamine 6G (2.34 × 10 -5 to 5.89 × 10 -4 M) and in different concentrations of LiCl, NaCl and KCl salts as supporting electrolytes. The monomer-dimer equilibrium of rhodamine B and 6G have been determined by chemometrics refinement of the absorption spectra obtained by thermometric titrations performed at different ionic strengths. The quantitative analysis of the data of undefined mixtures, was carried out by simultaneous resolution of the overlapping spectral bands in the whole set of absorption spectra. The dimerization constants are varied by changing the ionic strength and the degree of dimerization are decreased by increasing of the ionic strength of the medium. The enthalpy and entropy of the dimerization reactions were determined from the dependence of the equilibrium constants on the temperature (van't Hoff equation). From the thermodynamic results the T? S°-? H° plot was sketched. It shows a fairly good positive correlation which indicates the enthalpy-entropy compensation in the dimerization reactions (compensation effect).

Ghasemi, Jahanbakhsh; Niazi, Ali; Kubista, Mikael

2005-11-01

10

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

11

ChemTeacher: Titration  

NSDL National Science Digital Library

ChemTeacher compiles background information, videos, articles, demonstrations, worksheets and activities for high school teachers to use in their classrooms. The Titration page includes resources for teaching students about the theory and applications of titrations.

2012-07-24

12

A PC-based titrator for flow gradient titrations.  

PubMed

This paper describes a PC (personal computer) based titrator which was developed for gradient flow titrations. Concentration gradients were generated electrolytically or volumetrically in small tubes. Complete titration curves can be recorded on-line and evaluated automatically. The titrator can be used with all liquid flow detectors with low axial dispersion. The titrator was evaluated for the titration of thiosulphate with electrogenerated triiodide and for the titration of ammonia with electrogenerated hypobromite after continuous gas dialytic separation of ammonia from the sample solution. PMID:18924977

Fuhrmann, B; Spohn, U

1993-01-01

13

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

14

Optical Sensors for Manual and Automatic Titration in Undergraduate Laboratory  

Microsoft Academic Search

The classic undergraduate titration analysis is upgraded using instrumental detection of end point with color indicators. Several color sensors (CCD-based spectrophotometer, video camera with RGB digitalization, photodiode with appropriate filters) were tested in order to replace the visual indication of the end point with different indicators. The developed procedures show adequate characteristics such as a short titration time and accuracy

Alexander Y. Nazarenko

2010-01-01

15

Differentiating nonaqueous titration of aspirin, acetaminophen, and salicylamide mixtures.  

PubMed

Mixtures containing aspirin, acetaminophen, and salicylamide were assayed potentiometrically by nonaqueous titration. The difference in pKa values for these weak acids was sufficient to permit successful differentiation. The titrant was tetrabutylammonium hydroxide, and the titration solvent was dimethylformamide. The procedure was applied to commercial dosage forms. PMID:1151713

Rhodes, H J; DeNardo, J J; Bode, D W; Blake, M I

1975-08-01

16

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

17

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

18

Development of a simple desulfurization procedure for the determination of butyltins in complex sediment samples using gas chromatography-pulsed flame photometric detection.  

PubMed

In this study a rapid solid phase extraction (SPE) procedure was developed to minimize the effect of different sulfur species for the determination of butyltin in sediments. The organosulfur species and organotins were firstly retained on C8 cartridges and then organotins were selectively eluted and analyzed by gas chromatography-pulsed flame photometric detection (GC-PFPD). Optimal conditions for the SPE procedure were obtained using an experimental design approach. The method's accuracy was established by analyzing a certified reference material (CRM), BCR-646 freshwater sediment. The experimental values were found to be in agreement with the assigned values for butyltins. Finally, complex sediment samples collected from a Chilean harbor were analyzed using this methodology to demonstrate its analytical potential for the determination of butyltin in environmental samples. PMID:20298890

Bravo, M; Valenzuela, A; Quiroz, W; Pinto, M; Flores, M; Pinochet, H

2010-05-15

19

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; Swift, Wesley; Gural, Peter S.; Brown, Peter; Ellis, Jim (Technical Monitor)

2002-01-01

20

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

21

Titrating-Delay Matching-to-Sample in the Pigeon  

ERIC Educational Resources Information Center

The titrating-delay matching-to-sample (TDMTS) procedure offers researchers an additional behavioral task thought to capture some important features of remembering. In this procedure, the delay between sample offset and comparison onset adjusts as a function of the subject's performance. Specifically, correct matches increase the delay and…

Kangas, Brian D.; Vaidya, Manish; Branch, Marc N.

2010-01-01

22

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

23

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

24

Asphalt compatibility testing using the automated Heithaus titration test  

SciTech Connect

The Heithaus titration test or variations of the test have been used for over 35 years to predict compatibilities of blends of asphalts from different crude sources. Asphalt compatibility is determined from three calculated parameters that measure the state of peptization of an asphalt or asphalt blend. The parameter p{sub a} is a measure of the peptizability of the asphaltenes. The parameter p{sub a} is a measure of the peptizing power of the maltenes, and the parameter P, derived from p{sub a} and p{sub o} values, is a measure of the overall state of peptization of the asphalt or asphalt blend. In Heithaus original procedure, samples of asphalt were dissolved in toluene and titrated with n-heptane in order to initiate flocculation. The onset of flocculation was detected either by photography or by spotting a filter paper with a small amount of the titrated solution. Recently, an {open_quotes}automated{close_quotes} procedure, after Hotier and Robin, has been developed for use with asphalt. In the automated method UV-visible spectrophotometric detection measures the onset of flocculation as a peak with the percent transmittance plotted as a function of the volume of titrating solvent added to a solution of asphalt. The automated procedure has proven to be less operator dependent and much faster than the original Heithaus procedure. Results from the automated procedure show the data to be consistent with results from the original, {open_quotes}classical{close_quotes} Heithaus procedure.

Pauli, A.T. [Western Research Institute, Laramie, WY (United States)

1996-12-31

25

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

26

High-sensitivity titration microcalorimeter  

NASA Astrophysics Data System (ADS)

A differential titration microcalorimeter for studying intermolecular interactions in solutions has been designed. To increase the speed of the instrument, the dynamic correction method has been used. It has been shown that electrical calibration of the microcalorimeter is consistent with its chemical calibration. The use of the instrument for measuring the integral heats of dilution of 1-propanol has been demonstrated.

Velikov, A. A.; Grigoryev, S. V.; Chuikin, A. V.

2015-02-01

27

Determination of Acidity Constants by Gradient Flow-Injection Titration  

ERIC Educational Resources Information Center

A three-hour laboratory experiment, designed for an advanced undergraduate course in instrumental analysis that illustrates the application of the gradient chamber flow-injection titration (GCFIT) method with spectrophotometric detection to determine acidity constants is presented. The procedure involves the use of an acid-base indicator to obtain…

Conceicao, Antonio C. L.; Minas da Piedade, Manuel E.

2006-01-01

28

ChemTeacher Resource: Acid Base Titration  

NSDL National Science Digital Library

Acid-Base titration applet that plots pH changes as student adds acid or base. Gives choice of indicators. Compares plots for titration of traditional solution and a buffered solution. Can alter starting concentrations.

2012-07-30

29

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

30

High concentration aqueous sodium fluoride certified reference materials for forensic use certified by complexometric titration.  

PubMed

Sodium fluoride in concentrations of 1 to 2 % is used to prevent the formation of ethanol in blood and urine samples that are to be analysed for ethanol content. The majority of such samples form part of forensic investigations into alleged drunken driving. In South Africa, the laboratory performing the tests is required to prove that the sodium fluoride concentration in the blood samples is above 1 g/100 ml on receipt. This is done by using a fluoride ion-selective electrode calibrated with external aqueous solutions of sodium fluoride. The National Metrology Institute of South Africa (NMISA) prepares sodium fluoride solutions in concentrations from 0.3 to 3.0 g/100 ml. No other certified sodium fluoride reference solutions in these concentrations are available commercially. The sodium fluoride is certified by precipitation of the fluoride as lead chlorofluoride (PbClF) through the addition of a known excess of lead nitrate. The excess lead is back-titrated with ethylenediamine tetraacetic acid (EDTA) using a photometric electrode to detect the endpoint. Aqueous sodium fluoride solutions are prepared and the concentrations verified by the precipitation/back-titration method. This paper shows the application of a classical complexometric method to the certification of reference materials and describes the procedures for the preparation of the sodium fluoride solutions, verification of the concentrations, homogeneity and stability by primary titrimetry. It also briefly covers the calculation of uncertainty, the establishment of traceability and the quality control measures applied to ensure the quality of the certified reference materials (CRMs). PMID:25326884

Archer, Marcellé; Brits, Martin; Prevoo-Franzsen, Désirée; Quinn, Laura

2014-10-19

31

Evaluation of the 5 and 8 pH point titration methods for monitoring anaerobic digesters treating solid waste.  

PubMed

Simple titration methods certainly deserve consideration for on-site routine monitoring of volatile fatty acid (VFA) concentration and alkalinity during anaerobic digestion (AD), because of their simplicity, speed and cost-effectiveness. In this study, the 5 and 8 pH point titration methods for measuring the VFA concentration and carbonate system alkalinity (H2CO3*-alkalinity) were assessed and compared. For this purpose, synthetic solutions with known H2CO3*-alkalinity and VFA concentration as well as samples from anaerobic digesters treating three different kind of solid wastes were analysed. The results of these two related titration methods were verified with photometric and high-pressure liquid chromatography measurements. It was shown that photometric measurements lead to overestimations of the VFA concentration in the case of coloured samples. In contrast, the 5 pH point titration method provides an accurate estimation of the VFA concentration, clearly corresponding with the true value. Concerning the H2CO3*-alkalinity, the most accurate and precise estimations, showing very similar results for repeated measurements, were obtained using the 8 pH point titration. Overall, it was concluded that the 5 pH point titration method is the preferred method for the practical monitoring of AD of solid wastes due to its robustness, cost efficiency and user-friendliness. PMID:25224566

Vannecke, T P W; Lampens, D R A; Ekama, G A; Volcke, E I P

2015-04-01

32

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

33

A Tabular Approach to Titration Calculations  

ERIC Educational Resources Information Center

Titrations are common laboratory exercises in high school and university chemistry courses, because they are easy, relatively inexpensive, and they illustrate a number of fundamental chemical principles. While students have little difficulty with calculations involving a single titration step, there is a significant leap in conceptual difficulty…

Lim, Kieran F.

2012-01-01

34

Calibrationless determination of creatinine and ammonia by coulometric flow titration.  

PubMed

A precise and sensitive working microflow titration procedure was developed to determine creatinine and ammonia in urine samples. This procedure is based on enzymatic conversion of creatinine, gas diffusional membrane separation of the released ammonia into an acid acceptor stream, and coulometric titration of ammonia with hypobromite. The hypobromite is formed after the electrogeneration of bromine in an electrolyte containing 1.0 M NaBr and 0.1 M sodium borate adjusted to pH 8.5. The electrolysis current follows a triangle-programmed current-time course. An amperometric flow detector records the resulting mirror symmetrical titration curves, which show two equivalence points. The analyte concentration is calculated from the time difference between the equivalence points. For quantitative conversion of creatinine and quantitative separation of present and released ammonia no calibration is necessary to get accurate results. Both ammonia/ammonium and creatinine were determined in the range between 2 microM and 2 mM with relative standard deviations between 3.0 and 1.0% (n = 5). High recoveries were obtained for the analysis of diluted urine samples for both creatinine and ammonia. PMID:10906237

He, Z K; Fuhrmann, B; Spohn, U

2000-08-01

35

Micro coulometric titration in a liquid drop.  

PubMed

Miniaturized coulometric titration in a liquid drop has been investigated. Assays of ascorbic acid and thiosulfate with iodine titration were chosen as models. Constant volumes of falling liquid drops containing sample or reagent are manipulated via gravimetrical force to move along a slope hydrophobic path and directed to stop or to move out from an electrode. Such manipulation is useful for delivery of sample and reagents, in a way of flow without tubing. Electrochemical generation of titrant, in this case, iodine, is started at the electrode and micro coulometric titration can be performed in a drop by applying constant current. Timing in the titration can be made via naked eye with a stopwatch or via recording with a webcam camera connecting to a computer to detect the change due to the blue color complex of the excess iodine and starch. PMID:24054589

Kanyanee, Tinakorn; Fuekhad, Pongwasin; Grudpan, Kate

2013-10-15

36

Nanopore back titration analysis of dipicolinic acid.  

PubMed

Here, we report a novel label-free nanopore back titration method for the detection of dipicolinic acid, a marker molecule for bacterial spores. By competitive binding of the target analyte and a large ligand probe to metal ions, dipicolinic acid could be sensitively and selectively detected. This nanopore back titration approach should find useful applications in the detection of other species of medical, biological, or environmental importance if their direct detection is difficult to achieve. PMID:25074707

Han, Yujing; Zhou, Shuo; Wang, Liang; Guan, Xiyun

2015-02-01

37

Quantitative determination of wine highly volatile sulfur compounds by using automated headspace solid-phase microextraction and gas chromatography-pulsed flame photometric detection. Critical study and optimization of a new procedure.  

PubMed

The quantitative determination of wine volatile sulfur compounds by automated headspace solid-phase microextraction (HS-SPME) with a carboxen-polydimethylsiloxane (CAR-PDMS) fiber and subsequent gas chromatography-pulsed flame photometric detection (GC-PFPD) has been evaluated. The direct extraction of the sulfur compounds in 5 ml of wine has been found to suffer from matrix effects and short linear ranges, problems which could not be solved by the use of different internal standards or by multiple headspace SPME. These problems were attributed to saturation of the fiber and to competitive effects between analytes, internal standards and other wine volatiles. Another problem was the oxidation of analytes during the procedure. The reduction in sample volume by a factor 50 (0.1 ml diluted with water or brine) brought about a reduction in the amount of sulfur compounds taken in the fiber by a factor just 3.3. Consequently, a new procedure has been proposed. In a sealed vial containing 4.9 ml of saturated NaCl brine, the air is thoroughly displaced with nitrogen, and the wine (0.1 ml) and the internal standards (0.02 ml) are further introduced with a syringe through the vial septum. This sample is extracted at 35 degrees C for 20 min. This procedure makes a satisfactory determination possible of hydrogen sulfide, methanethiol, ethanethiol, dimethyl sulfide, diethyl sulfide and dimethyl disulfide. The linear dynamic ranges cover the normal ranges of occurrence of these analytes in wine with typical r2 between 0.9823 and 0.9980. Reproducibility in real samples ranges from 10 to 20% and repeatability is better than 10% in most cases. The method accuracy is satisfactory, with errors below 20% for hydrogen sulfide and mostly below 10% for the other compounds. The proposed method has been applied to the analysis of 34 Spanish wines. PMID:17207804

López, Ricardo; Lapeña, Ana Cristina; Cacho, Juan; Ferreira, Vicente

2007-03-01

38

Photometric Classification of Supernovae  

NASA Astrophysics Data System (ADS)

Photometric classification of supernova cosmology samples currently depends on a limited number of core-collapse templates for both the classification and production of simulated test samples. We present the results of systematic template variations for both classification and simulation, using the sncosmo package to classify core-collapse supernovae simulated with the SNANA package. Our goal is to understand better the template uncertainties in future photometrically-classified supernova cosmology samples.

Zimmerman, Daniel; Cunningham, John; Kuhlmann, Steve; Gupta, Ravi; Kovacs, Eve; Spinka, Harold

2015-01-01

39

A Monte Carlo Study of Titrating Polyelectrolytes  

E-print Network

A Monte Carlo Study of Titrating Polyelectrolytes Magnus Ullner y and Bo J¨onsson z Physical, Sweden Journal of Chemical Physics 104, 3048­3057 (1996) Monte Carlo simulations have been used to study of the polymer more difficult and biases the conformations towards more extended structures. In the Monte Carlo

Peterson, Carsten

40

A Monte Carlo Study of Titrating Polyelectrolytes  

E-print Network

A Monte Carlo Study of Titrating Polyelectrolytes Magnus Ullnery and Bo Jonssonz Physical Chemistry Journal of Chemical Physics 104, 3048-3057 (1996) Monte Carlo simulations have been used to study three di the conformations towards more extended structures. In the Monte Carlo simulations presented here, focus

Peterson, Carsten

41

Colorimetric Titration Experiment for the Undergraduate Laboratory.  

ERIC Educational Resources Information Center

Describes a colorimetric titration instrument usable in the undergraduate laboratory that fulfills the objectives of ruggedness, freedom from ambient light interference, and low cost. Although accessories can be added (raising the price), the basic instrument is low priced and can be used manually with a simple voltmeter. (JN)

Lopez, Edwin; Vassos, Basil H.

1984-01-01

42

Coulometric titration with gas diffusion separation step  

Microsoft Academic Search

Coulometric titration is employed in combination with a gas diffusion step for the quantitative separation and determination of volatile substances. Complete separation is brought about by filling the sample into a closed circulating loop and transporting it repeatedly past a microporous membrane. The combination of membrane separation module with the coulometric cell allows rapid separation and exploitation of the precise

M. Hahn; H. H. Rüttinger; H. Matschiner

1992-01-01

43

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

44

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

45

Surfactant titration of nanoparticle-protein corona.  

PubMed

Nanoparticles (NP), when exposed to biological fluids, are coated by specific proteins that form the so-called protein corona. While some adsorbing proteins exchange with the surroundings on a short time scale, described as a "dynamic" corona, others with higher affinity and long-lived interaction with the NP surface form a "hard" corona (HC), which is believed to mediate NP interaction with cellular machineries. In-depth NP protein corona characterization is therefore a necessary step in understanding the relationship between surface layer structure and biological outcomes. In the present work, we evaluate the protein composition and stability over time and we systematically challenge the formed complexes with surfactants. Each challenge is characterized through different physicochemical measurements (dynamic light scattering, ?-potential, and differential centrifugal sedimentation) alongside proteomic evaluation in titration type experiments (surfactant titration). 100 nm silicon oxide (Si) and 100 nm carboxylated polystyrene (PS-COOH) NPs cloaked by human plasma HC were titrated with 3-[(3-Cholamidopropyl) dimethylammonio]-1-propanesulfonate (CHAPS, zwitterionic), Triton X-100 (nonionic), sodium dodecyl sulfate (SDS, anionic), and dodecyltrimethylammonium bromide (DTAB, cationic) surfactants. Composition and density of HC together with size and ?-potential of NP-HC complexes were tracked at each step after surfactant titration. Results on Si NP-HC complexes showed that SDS removes most of the HC, while DTAB induces NP agglomeration. Analogous results were obtained for PS NP-HC complexes. Interestingly, CHAPS and Triton X-100, thanks to similar surface binding preferences, enable selective extraction of apolipoprotein AI (ApoAI) from Si NP hard coronas, leaving unaltered the dispersion physicochemical properties. These findings indicate that surfactant titration can enable the study of NP-HC stability through surfactant variation and also selective separation of certain proteins from the HC. This approach thus has an immediate analytical value as well as potential applications in HC engineering. PMID:25350777

Maiolo, Daniele; Bergese, Paolo; Mahon, Eugene; Dawson, Kenneth A; Monopoli, Marco P

2014-12-16

46

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

47

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

48

An Olfactory Indicator for Acid-Base Titrations.  

ERIC Educational Resources Information Center

The use of an olfactory acid-base indicator in titrations for visually impaired students is discussed. Potential olfactory indicators include eugenol, thymol, vanillin, and thiophenol. Titrations performed with each indicator with eugenol proved to be successful. (KR)

Flair, Mark N.; Setzer, William N.

1990-01-01

49

Coupled chemical processes at clay/electrolyte interface: a batch titration study of Na-montmorillonites.  

PubMed

The present work addresses the protolytic charge of montmorillonite, which occurs on the broken-bond sites at the particle edges. The purpose is to overcome the general difficulty arising in potentiometric titration due to coupled side reactions, which severely impede the titrant budget (partial dissolution of the clay and of secondary phases, hydrolysis and readsorption of dissolved species, cation exchange). Batch potentiometric titrations were carried out on the montmorillonite fractions extracted from two bentonites (MX80 and SWy2) to quantify their protolytic charge. The effects of equilibration time (24 h and 7 days), pH from 4 to 10, and ionic strength (0.1 and 0.01 mol L(-1)) were extensively studied for the MX80 sample. Quantification of dissolution was achieved by analysis of the equilibrium solutions for dissolved species and by La(3+) exchange of the readsorbed species. The results clearly show that secondary phases such as iron- or silica-rich minerals contribute to the dissolved species, according to the nature of the raw bentonite. Furthermore, readsorption affects significant amounts of dissolved species. The overconsumption of proton/hydroxide due to dissolution, readsorption, and hydrolysis of dissolved species was evaluated using a self-consistent thermodynamic calculation. The ability of such calculation to correct the raw titration curves in order to extract the titrable surface charge of montmorillonite was evaluated by comparison with the continuous titration procedure. Especially in the alkaline domain, correcting the raw batch titration curves for the measured side reactions failed to reproduce the continuous titration curves. These observations demonstrate the limitations of the batch titration method and the superiority of fast, continuous methods for quantifying the dissociable surface charge of clays. PMID:16777124

Duc, Myriam; Thomas, Fabien; Gaboriaud, Fabien

2006-08-15

50

Kinetic Titration Series with Biolayer Interferometry  

PubMed Central

Biolayer interferometry is a method to analyze protein interactions in real-time. In this study, we illustrate the usefulness to quantitatively analyze high affinity protein ligand interactions employing a kinetic titration series for characterizing the interactions between two pairs of interaction patterns, in particular immunoglobulin G and protein G B1 as well as scFv IC16 and amyloid beta (1–42). Kinetic titration series are commonly used in surface plasmon resonance and involve sequential injections of analyte over a desired concentration range on a single ligand coated sensor chip without waiting for complete dissociation between the injections. We show that applying this method to biolayer interferometry is straightforward and i) circumvents problems in data evaluation caused by unavoidable sensor differences, ii) saves resources and iii) increases throughput if screening a multitude of different analyte/ligand combinations. PMID:25229647

Frenzel, Daniel; Willbold, Dieter

2014-01-01

51

Infrared titration of aqueous sulfuric acid  

Microsoft Academic Search

This paper presents the infrared (IR) titration of aqueous sulfuric acid solutions (0.50 M) obtained by the attenuated total reflection (ATR) sampling technique. After subtracting the water spectra, the spectra of the ionic species of HâSOâ in the 0--14 pH range were separated by factor analysis (FA) which also gave their abundance. The results were in agreement with the theoretical

Jean-Joseph Max; C. Menichelli; Camille Chapados

2000-01-01

52

Analysis of Cooperativity by Isothermal Titration Calorimetry  

PubMed Central

Cooperative binding pervades Nature. This review discusses the use of isothermal titration calorimetry (ITC) in the identification and characterisation of cooperativity in biological interactions. ITC has broad scope in the analysis of cooperativity as it determines binding stiochiometries, affinities and thermodynamic parameters, including enthalpy and entropy in a single experiment. Examples from the literature are used to demonstrate the applicability of ITC in the characterisation of cooperative systems. PMID:20111687

Brown, Alan

2009-01-01

53

LABORATORY EXPERIMENT 6 PRECIPITATION TITRATION WITH SILVER NITRATE.  

E-print Network

LABORATORY EXPERIMENT 6 PRECIPITATION TITRATION WITH SILVER NITRATE. The AgNO3 solution (~0.02 M in the titration of chloride ion with silver nitrate. The first excess of titrant results in the formation of a red Ag2CrO4. Calculations: From the volume of silver nitrate solution used fopr titration, calculate

Nazarenko, Alexander

54

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

55

Workshop on the Strömvil Photometric System  

NASA Astrophysics Data System (ADS)

On October 6 - 8 a workshop on the Strömvil Photometric System was held in Vilnius and at the Moletai Observatory in Lithuania. Papers were given concerning the creation and use of the system, its special abilities to recognize stars of all spectral types and peculiarities even in the case of areas with high values of interstellar reddening. Reports were made on studies of synthetic photometry to investigate the classification properties of photometric systems. The photometric design of the planned GAIA orbiting observatory was outlined. Current observations being made in the system on the Vatican Advanced Technology Telescope were described and plans for future work at this site were discussed. The members of the workshop agreed on the following recommendations: A. All the groups cooperating in Strömvil measures should use common observing and reduction procedures. In reduction this means using IRAF and DAOPHOT. B. A database will be set up at ITPA which will contain information from each observatory concerning the CCD chip(s) being used, the observers and the details of observations made at that site. Data on standard stars and regions as well as areas used for scientific studies will be included. C. Error ellipses (from studies with synthetic photometry calibrated in temperature and log g) will be calculated for the various systems being proposed for GAIA, for stars of V = 16 and 18 magnitude. The choice of a photometric system for GAIA should be based on the classification abilities of the system. Since the satellite will observe stars in areas which are heavily reddened the system must be able to correct for reddening effects. D. The Workshop members recommended that a meeting be held in 2000 to discuss the properties of photometric systems proposed for GAIA and the methods by which a choice of the final system for GAIA should be made.

Philip, A. G. Davis; Straižys, V.; Høg, E.

1999-12-01

56

Automated titration method for use on blended asphalts  

DOEpatents

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

57

Technical Note: How long can seawater oxygen samples be stored before titration?  

NASA Astrophysics Data System (ADS)

The concentration of dissolved oxygen in seawater is routinely measured using a standardized titration method that involves analysis shortly after the water sample has been collected. However, none of the existing procedural documents are specific about how soon after collection the titration has to be done. Here, we report on a small number of samples where duplicates were collected and one batch was titrated within days after collection, while the other batch was stored for several weeks before titration. In addition, for a subset of the samples a third batch was taken that was stored like the others but with a particular chemical already added before storage. Comparison between the batches confirms that there is no significant difference between the ones that were stored and the ones that were analyzed sooner, indicating that a month-long storage period is acceptable. The implication of this is that such oxygen samples do not necessarily have to be analyzed while still on the ship; instead, it is possible to transport them ashore for analysis there.

Lankhorst, M.; Chavez, G.; Nam, S. H.; Send, U.

2014-10-01

58

Carboxylic Acid Unknowns and Titration 90 CARBOXYLIC ACID UNKNOWN  

E-print Network

Point/Boiling Point If your carboxylic acid is a solid, take its melting point. If it is a liquid, take its micro- boiling point. C. Titration/Neutralization EquivalenceMolecular Weight Determination WeighCarboxylic Acid Unknowns and Titration 90 CARBOXYLIC ACID UNKNOWN A. Solubility Tests: Water, Na

Jasperse, Craig P.

59

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

60

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

61

Microscale pH Titrations Using an Automatic Pipet.  

ERIC Educational Resources Information Center

Presents a microscale pH titration technique that utilizes an automatic pipet. A small aliquot (1-5 mL) of the analyte solution is titrated with repeated additions of titrant, and the pH is determined after each delivery. The equivalence point is determined graphically by either the second derivative method or a Gran plot. The pipet can be…

Flint, Edward B.; Kortz, Carrie L.; Taylor, Max A.

2002-01-01

62

Students' integration of multiple representations in a titration experiment  

NASA Astrophysics Data System (ADS)

A complete understanding of a chemical concept is dependent upon a student's ability to understand the microscopic or particulate nature of the phenomenon and integrate the microscopic, symbolic, and macroscopic representations of the phenomenon. Acid-base chemistry is a general chemistry topic requiring students to understand the topics of chemical reactions, solutions, and equilibrium presented earlier in the course. In this study, twenty-five student volunteers from a second semester general chemistry course completed two interviews. The first interview was completed prior to any classroom instruction on acids and bases. The second interview took place after classroom instruction, a prelab activity consisting of a titration calculation worksheet, a titration computer simulation, or a microscopic level animation of a titration, and two microcomputer-based laboratory (MBL) titration experiments. During the interviews, participants were asked to define and describe acid-base concepts and in the second interview they also drew the microscopic representations of four stages in an acid-base titration. An analysis of the data showed that participants had integrated the three representations of an acid-base titration to varying degrees. While some participants showed complete understanding of acids, bases, titrations, and solution chemistry, other participants showed several alternative conceptions concerning strong acid and base dissociation, the formation of titration products, and the dissociation of soluble salts. Before instruction, participants' definitions of acid, base, and pH were brief and consisted of descriptive terms. After instruction, the definitions were more scientific and reflected the definitions presented during classroom instruction.

Kunze, Nicole M.

63

Characterization of Petroleum Sulfonates by a Nonaqueous Titration Method  

Microsoft Academic Search

A new method is described for the determination of the equivalent weight for petroleum sulfonates. The method is based on the direct acidimetric titration of the sulfonate in acetic acid\\/acetic anhydride solvent using a titrant of perchloric acid in dioxane. From the titration, the moles of perchloric acid required to react with the sulfonate is measured. The equivalent weight is

Kim Voss; Clark Bricker; M. J. Michnick; G. P. Willhite

1981-01-01

64

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

SciTech Connect

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 the amino-acid sequence of the protein. To determine these pK{sub a}`s, a simple theory was used which assumes that the pK{sub a}`s are independent from each other in the protein and are equal to their pK{sub a} values in free amino-acid solution (Independent-Site Theory, IST). Residue pK{sub a}`s were obtained from amino-acid hydrogen-ion titrations at three different KCl concentrations corresponding to 0.1M, 1.0M and 3.0M ionic strength. After construction of a suitable apparatus, the experimental procedure and data reduction were computerized to perform a large number of titrations. Most measured pK{sub a}`s showed high reproducibility (the difference of pK{sub a} values observed between two experiments was less than 0.05). For IS = 0.1M, observed pK{sub a}`s agreed with literature values to within a few hundredths of a pH unit. Furthermore, the ionic-strength dependence of the pK{sub a}`s followed the trends reported in the literature, viz. pK{sub a} values decrease with increasing ionic strength until they reach a minimum at about IS = 0.5M. At still higher IS, pK{sub a}`s increase as the ionic strength rises to 3M. The known pK{sub a}`s of all titratable groups in a protein were used with the IST to give a first approximation of how the protein net charge varies with pH at high ionic strength. A comparison of the titration curves based on the IST with experimental lysozyme and {alpha}-chymotrypsin titration data indicates acceptable agreement at IS = 0.1M. However, comparison of measured and calculated titration curves at IS = 1M and IS = 3M indicates only quantitative agreement.

Fergg, F. [Technische Universitaet Muenchen (Germany); Kuehner, D.E.; Blanch, H.W.; Prausnitz, J.M. [Lawrence Berkeley Lab., CA (United States)

1994-12-01

65

Titration and hysteresis in epigenetic chromatin silencing  

NASA Astrophysics Data System (ADS)

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.

Dayarian, Adel; Sengupta, Anirvan M.

2013-06-01

66

Astronomical Research Institute Photometric Results  

NASA Astrophysics Data System (ADS)

The Astronomical Research Institute (ARI) conducts astrometric and photometric studies of asteroids with a concentration on near-Earth objects (NEOs). A 0.76-m autoscope was used for photometric studies of seven asteroids of which two were main-belt targets and five were NEOs, including one potentially hazardous asteroid (PHA). These objects are: 3122 Florence, 3960 Chaliubieju, 5143 Heracles, (6455) 1992 HE, (36284) 2000 DM8, (62128) 2000 SO1, and 2010 LF86.

Linder, Tyler R.; Sampson, Ryan; Holmes, Robert

2013-01-01

67

Studies on the acidity of mordenite and ZSM-5. 1. Determination of Broensted acid site concentrations in mordenite and ZSM-5 by conductometric titration  

SciTech Connect

The Broensted acidity of H-mordenite and H-ZSM-5 samples of varying proton concentration has been studied using aqueous conductometric titration, IR spectroscopy, and aqueous potentiometric titration. Good agreement is observed between Broensted acid site concentrations determined by conductometric titration and IR measurements, while indirect potentiometric titration affords acid site concentrations consistently lower than those measured using the conductometric technique. This finding is rationalized on the basis that, in a conductometric titration, all the accessible Broensted acid sites are direct;y titrated, whereas in the potentiometric procedure utilized, only those protons which can be ion-exchanged out of the zeolite are titrated. After allowing for the presence of extraframework aluminum in the zeolites (determined by [sup 27]Al NMR), the measured acidity for H-mordenite is found to increase linearly with increasing Al content within the range 0-1.5 mmol Al/g but appears to reach a limiting value at higher Al concentrations. For H-ZSM-5, the experimentally determined number of Broensted acid sites is also found to be linearly dependent on the Al molar fraction within the range measured (0-1.20 mmol Al/g). For both series of zeolite samples, the measured acidity is generally found to be less than the theoretical maximum calculated on the basis of an H[sup +]/Al ratio of 1. 43 refs., 10 figs., 4 tabs.

Crocker, M.; Herold, R.H.M.; Sonnemans, M.H.W.; Emeis, C.A.; Wilson, A.E.; Moolen, J.N. van der (Koninklijke/Shell-Laboratorium, Amsterdam (Netherlands))

1993-01-14

68

Concentration-related response potentiometric titrations to study the interaction of small molecules with large biomolecules.  

PubMed

In the present paper, the utility of a special potentiometric titration approach for recognition and calculation of biomolecule/small-molecule interactions is reported. This approach is fast, sensitive, reproducible, and inexpensive in comparison to the other methods for the determination of the association constant values (Ka) and the interaction energies (?G). The potentiometric titration measurement is based on the use of a classical polymeric membrane indicator electrode in a solution of the small-molecule ligand. The biomolecule is used as a titrant. The potential is measured versus a reference electrode and transformed into a concentration-related signal over the entire concentration interval, also at low concentrations, where the millivolt (y-axis) versus log canalyte (x-axis) potentiometric calibration curve is not linear. In the procedure, Ka is calculated for the interaction of cocaine with a cocaine binding aptamer and with an anticocaine antibody. To study the selectivity and cross-reactivity, other oligonucleotides and aptamers are tested, as well as other small ligand molecules such as tetrakis(4-chlorophenyl)borate, metergoline, lidocaine, and bromhexine. The calculated Ka compared favorably to the value reported in the literature using surface plasmon resonance. The potentiometric titration approach called "concentration-related response potentiometry" is used to study molecular interaction for seven macromolecular target molecules and four small-molecule ligands. PMID:25390494

Hamidi-Asl, Ezat; Daems, Devin; De Wael, Karolien; Van Camp, Guy; Nagels, Luc J

2014-12-16

69

Photometric redshifts for the NGVS  

NASA Astrophysics Data System (ADS)

We present the photometric redshift catalog for the Next Generation Virgo Cluster Survey (NGVS), a 104 deg^2 optical imaging survey centered on the Virgo cluster in the u^*, g, r ,i, z bandpasses at point source depth of 25-26 ABmag. It already is the new optical reference survey for the study of the Virgo cluster, and will be also used for multiple ancillary programs. To obtain photometric redshifts, we perform accurate photometry, through the PSF-homogenization of our data. We then estimate the photometric redshifts using Le Phare and BPZ codes, adding a new prior extended down to i_{AB}=12.5 mag. We assess the accuracy of our photometric redshifts as a function of magnitude and redshift using ˜80,000 spectroscopic redshifts from public surveys. For i_{AB} < 23 mag or z_{phot} < 1 galaxies, we obtain photometric redshifts with |bias| < 0.02, a scatter increasing with magnitude (from 0.02 to 0.05), and less than 5% outliers.

Raichoor, A.; Mei, S.; Erben, T.; Hildebrandt, H.; Huertas-Company, M.; Ilbert, O.; Licitra, R.; Ball, N. M.; Boissier, S.; Boselli, A.; Chen, Y.-T.; Côté, P.; Cuillandre, J.-C.; Duc, P. A.; Durrell, P. R.; Ferrarese, L.; Guhathakurta, P.; Gwyn, S. D. J.; Kavelaars, J. J.; Lancon, A.; Liu, C.; MacArthur, L. A.; Muller, M.; Muñoz, R. P.; Peng, E. W.; Puzia, T. H.; Sawicki, M.; Toloba, E.; Van Waerbeke, L.; Woods, D.; Zhang, H.

2014-12-01

70

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

71

Photometric Redshifts of Submillimeter Galaxies  

NASA Astrophysics Data System (ADS)

We use the photometric redshift method of Chakrabarti & 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 >~ z >~ 0.3) and luminosities, finding an average accuracy in (1 + z phot)/(1 + z 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 ?m flux >~ 5 mJy, contribute 15% of the SFRD from all ultraluminous infrared galaxies (L IR >~ 1012 L ?), and 3% of the total SFRD at z ~ 2.

Chakrabarti, Sukanya; Magnelli, Benjamin; McKee, Christopher F.; Lutz, Dieter; Berta, Stefano; Popesso, Paola; Pozzi, Francesca

2013-08-01

72

Determination of uranium by direct titration with dipicolinic acid  

SciTech Connect

Direct titration of uranium with dipicolinic acid, in the presence of Arsenazo I, is a simple, precise, and accurate method for uranium determination. The method is particularly attractive because it can be totally automated. Detecting the end point (color change from blue to pink) depends on the concentration range. For the Micro Method (1 to 20 ppM U in the solution titrated), the gradual color change is monitored spectrophotometrically. For the Macro Method (20 to 300 ppM), the end point is determined either visually or spectrophotometrically. The spectrophotometric end point is computed by fitting the titration curve. The relative standard deviation is +-1 to 3% for the Micro Method and +-0.3% for the Macro Method.

Baumann, E.W.

1984-07-12

73

Constant-Current Coulometric Titration of Hydrochloric Acid  

NASA Astrophysics Data System (ADS)

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 report how the elctrolysis of an aqueous solution can be used to determine the concentration of hydrochloric acid in a coulometric titration.

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

1996-07-01

74

Photometric Variability in the FSVS  

Microsoft Academic Search

The Faint Sky Variability Survey (FSVS) is aimed at nding pho- tometric and\\/or astrometric variable objects between 16th and 24th mag on time-scales between tens of minutes and years with photometric precisions ranging from 3 millimag to 0.2 mag. An area of 23 deg2, located at mid and high Galactic latitudes, was covered using the Wide Field Camera (WFC) on

L. Morales-Rueda; P. J. Groot; T. Augusteijn; G. Nelemans; P. M. Vreeswijk; E. J. M. van den Besselaar

75

Photometrics at Sandia National Laboratories  

SciTech Connect

This report highlights Sandia National Laboratories' work in the following areas: photometrics and optical development; still and time-lapse photography; real-time motion photography; high-speed photography; image-motion photography; schlieren photography; ultra-high-speed photography; electronic imaging; shuttered video and high-speed video; infrared imaging radiometry; exoatmospheric photography and videography; microdensitometry and image analysis; and optical system design and development.

McWilliams, J.Y.; Hill, R.A.; Hughes, R.L. (eds.)

1990-07-01

76

LABORATORY EXPERIMENT 5 PRECIPITATION TITRATION WITH SILVER NITRATE.  

E-print Network

, it is desirable to maintain the particles of silver chloride in the colloidal state. INDICATOR DichlorofluoresceinLABORATORY EXPERIMENT 5 PRECIPITATION TITRATION WITH SILVER NITRATE. The AgNO3 solution (~0.02 M surrounding the silver chloride and imparts color to the solid. To obtain a satisfactory color change

Nazarenko, Alexander

77

SUBVISIBLE RETINAL LASER THERAPY Titration Algorithm and Tissue Response  

E-print Network

been used within a wide range of laser settings: from intense burns to nondamaging exposures. However and calibrate a computational model­based titration algorithm for predictable laser dosimetry ranging from by adjusting laser power to produce a barely visible lesion at 20 ms pulse duration, which is defined

Palanker, Daniel

78

Characterisation of iron binding ligands in seawater by reverse titration.  

PubMed

Here we demonstrate the use of reverse titration - competitive ligand exchange-adsorptive cathodic stripping voltammetry (RT-CLE-ACSV) for the analysis of iron (Fe) binding ligands in seawater. In contrast to the forward titration, which examines excess ligands in solution, RT-CLE-ACSV examines the existing Fe-ligand complexes by increasing the concentration of added (electroactive) ligand (1-nitroso-2-naphthol) and analysis of the proportion of Fe bound to the added ligand. The data manipulation allows the accurate characterisation of ligands at equal or lower concentrations than Fe in seawater, and disregards electrochemically inert dissolved Fe such as some colloidal phases. The method is thus superior to the forward titration in environments with high Fe and low ligand concentrations or high concentrations of inert Fe. We validated the technique using the siderophore ligand ferrioxamine B, and observed a stability constant [Formula: see text] of 0.74-4.37×10(21) mol(-1), in agreement with previous results. We also successfully analysed samples from coastal waters and a deep ocean hydrothermal plume. Samples from these environments could not be analysed with confidence using the forward titration, highlighting the effectiveness of the RT-CLE-ACSV technique in waters with high concentrations of inert Fe. PMID:23427800

Hawkes, Jeffrey A; Gledhill, Martha; Connelly, Douglas P; Achterberg, Eric P

2013-03-01

79

RESEARCH Open Access Continuous positive airway pressure titration in  

E-print Network

RESEARCH Open Access Continuous positive airway pressure titration in infants with severe upper airway obstruction or bronchopulmonary dysplasia Sonia Khirani1,2 , Adriana Ramirez2,3 , Sabrina Aloui2 airway obstruction (UAO) or bronchopulmonary dysplasia (BPD). Methods: The breathing pattern

Paris-Sud XI, Université de

80

BPZ: Bayesian Photometric Redshift Code  

NASA Astrophysics Data System (ADS)

Photometric redshift estimation is becoming an increasingly important technique, although the currently existing methods present several shortcomings which hinder their application. Most of those drawbacks are efficiently eliminated when Bayesian probability is consistently applied to this problem. The use of prior probabilities and Bayesian marginalization allows the inclusion of valuable information, e.g. the redshift distributions or the galaxy type mix, which is often ignored by other methods. In those cases when the a priori information is insufficient, it is shown how to `calibrate' the prior distributions, using even the data under consideration. There is an excellent agreement between the 108 HDF spectroscopic redshifts and the predictions of the method, with a rms error Delta z/(1+z_spec) = 0.08 up to z<6 and no systematic biases nor outliers. The results obtained are more reliable than those of standard techniques even when the latter include near-IR colors. The Bayesian formalism developed here can be generalized to deal with a wide range of problems which make use of photometric redshifts, e.g. the estimation of individual galaxy characteristics as the metallicity, dust content, etc., or the study of galaxy evolution and the cosmological parameters from large multicolor surveys. Finally, using Bayesian probability it is possible to develop an integrated statistical method for cluster mass reconstruction which simultaneously considers the information provided by gravitational lensing and photometric redshifts.

Benítez, Narciso

2011-08-01

81

[A photometric method for determining formaldehyde in the air using phenol-formaldehyde resins].  

PubMed

Photometric procedure of methanol determination based on its reaction with phenyl hydrazin and dinitride sulfanilic acid was developed. The procedure was highly sensitive (0.1 microgram in the analyzed volume) and selective in the presence of phenol, furyl alcohol, methanol and furfurol. PMID:2591814

Putilina, O N; Tsygal'nitskaia, Z F

1989-01-01

82

OZONE CALIBRATION AND AUDIT BY GAS PHASE TITRATION IN EXCESS OZONE. BENDIX (TRADE NAME) TRANSPORTABLE FIELD CALIBRATION SYSTEM, MODELS 8861D AND 8861DA  

EPA Science Inventory

Detailed procedures for the dynamic calibration and audit of chemiluminescence ozone analyzers are presented. The calibrations and audits are performed by means of a gas phase titration technique using the rapid gas phase reaction between nitric oxide and ozone with excess ozone ...

83

Optimised determinations of water in ethanol by encoded photometric near-infrared spectroscopy: a special case of sequential standard addition calibration.  

PubMed

A special limiting case of sequential standard addition calibration (S-SAC) has been applied to measurement of the water content of ethanol using encoded photometric near infrared spectroscopy. The method has shown good comparability with certified reference materials and to measurements made by Karl Fischer titration. The technique is quick and easy to use and should have application in high throughput and process measurement, for instance in biofuels analysis at port-of-entry or in bio-refineries. The characteristics of this limiting case of S-SAC have been fully described, and the corrections required to the value obtained by extrapolation to avoid bias have been calculated. The precision of the S-SAC procedure has been studied, and proposals have been made to optimise this with respect to the analytical precision. The technique should be applicable for the measurement of water in ethanol mass fractions of up to 0.1g g(-1) with an expanded uncertainty of less than 2% (relative). PMID:21414435

Brown, Richard J C; Keates, Adam C; Brown, Andrew S

2011-03-25

84

Propagation of error in fulvic acid titration data: a comparison of three analytical methods  

E-print Network

Propagation of error in fulvic acid titration data: a comparison of three analytical methods selective electrode and fluorescence quenching data and Waite and Morel (3) compared fulvic acid titrations

Morel, François M. M.

85

Electrophoretic separation of alginic sodium diester and sodium hexametaphosphate in chondroitin sulfate that interfere with the cetylpyridinium chloride titration assay.  

PubMed

The most commonly used chondroitin sulfate (CS) assay method is cetylpyridinium chloride (CPC) titration. Cellulose acetate membrane electrophoresis (CAME) is the technique used for detection of impurities in the U.S. Pharmacopeia's CS monograph. Because CPC titration is a relatively nonspecific quantitative technique, the apparent amount of CS as determined by CPC titration alone may not reflect the true amount of CS due to possible interference with the CPC assay by impurities that contain CPC titratable functional groups. When CAME is used in conjunction with CPC titration, certain non-CS and adulterants can be visualized and estimated, and a true value for CS can be assigned once the presence of these non-CS impurities has been ruled out. This study examines conjunct application of CPC and CAME in ascertaining CS assay and purity in the presence of certain adulterants. These include propylene glycol alginate sulfate sodium, known in commerce as alginic sodium diester (ASD), and Zero One (Z1), a water-soluble agent newly reported in the CS marketplace and subsequently identified as sodium hexametaphosphate. ASD, Z1, and CS are similar in physical appearance and solubility in water and ethanol. They are also titratable anions and form ionic pairs with CPC, therefore interfering with the CPC titration assay for CS CAME separates these adulterants from each other and from CS by differences in their electrophoretic mobility. CAME is able to detect these impurities in CS at levels as low as 0.66% by weight. Although it is recommended that a method for detecting impurities (e.g., CAME) be used in cormbination with relatively nonspecific assay methods such as CPC titration, this is seldom done in practice. Assay results for CS derived fromn CPC titration may, therefore, be misleading, leaving the CS supply chain vulnerable to adulteration. In this study, the authors investigated ASD and Z1 adulteration of CS and developed an electrophoretic separation of these adulterants in CS and procedures to isolate ASD from CS matrixes containing these adulterants. The authors describe in this paper utilization of an orthogonal approach to establish the identity of Z1 as sodium hexametaphosphate and to confirm the identity of ASD, including ethanol fractionation, FTIR spectroscopy, differential scanning calorimetry, and NMR spectroscopy. The authors suggest that CAME is a cost-effective and easy to use methodfor detecting certain impurities in CS raw ingredients and recommend that CPC and CAME be used in combination by QC laboratories as a means of effectively deterring the practice of adulterating CS raw materials with the known adulterants ASD and Z1 and/or other non-chondroitin substances that can be separated from CSby CAME and that exhibit CPC titration behavior similar to CS. PMID:25372663

Weiguo, Zhang; Giancaspro, Gabriel; Adams, Kristie M; Neal-Kababick, James; Hildreth, Jana; Li, Aishan; Roman, Mark C; Betz, Joseph M

2014-01-01

86

Development of a novel baculovirus titration method using the Enzyme-linked immunosorbent spot (ELISPOT) assay.  

PubMed

The baculovirus expression vector system (BEVS) is one of the most powerful methods for production of recombinant proteins for research or commercial purposes. Titration of viable virus in insect cell culture is often required when BEVS is used for basic research or bioprocessing. An enzyme-linked immunosorbent spot (ELISPOT) assay using monoclonal antibodies against the major capsid protein VP39 of both Autographa californica nuclear polyhedrosis virus (AcMNPV) and Bombyx mori nuclear polyhedrosis virus (BmNPV) was developed for baculovirus quantitation at 48h post-infection. The titer was determined by visualizing infected insect cells as blue spots and automated spot counting was achieved with ELISPOT hardware and software. Log-scale comparison of the results between the ELISPOT assay and a conventional end point dilution assay using a fluorescent marker showed a good correlation for both AcMNPV (R(2)=0.9980, p<0.05) and BmNPV (R(2)=0.9834, p<0.05). In conclusion, a novel, rapid and semi-automated procedure for titrating baculovirus was developed based on the specific immunostaining of infected cells followed by automated spot counting. PMID:23274754

Wang, Wei; Cheng, Tong; Ma, Ke; Xia, Dezhen; Wang, Yongmei; Liu, Jian; Du, Hailian; Shih, James Wai Kuo; Zhang, Jun; Zhao, Qinjian; Xia, Ningshao

2013-03-01

87

Photometric commissioning results from MINERVA  

NASA Astrophysics Data System (ADS)

MINERVA is a robotic observatory with four 0.7 meter telescopes at Mt. Hopkins, Arizona, dedicated to precise photometry and radial velocity observations of bright, nearby stars for the discovery and characterization of small exoplanets. Here we present the first photometric results from MINERVA during commissioning at our test facility in Pasadena, California, demonstrating sub-millimag precision on 3-5 minute timescales over several hours. These results show that MINERVA is well-equipped to address its secondary science goal of searching for transits of known and newly discovered super-Earth exoplanets detected by radial velocity, including potential detections from the MINERVA spectrograph.

Eastman, Jason D.; Swift, Jonathan; Beatty, Thomas G.; Bottom, Michael; Johnson, John; Wright, Jason; McCrady, Nate; Wittenmyer, Robert A.; Riddle, Reed L.; Plavchan, Peter; Muirhead, Philip Steven; Blake, Cullen; Zhao, Ming

2015-01-01

88

Sloan Digital Sky Survey Photometric Calibration Revisited  

SciTech Connect

The Sloan Digital Sky Survey calibration is revisited to obtain the most accurate photometric calibration. A small but significant error is found in the flat-fielding of the Photometric telescope used for calibration. Two SDSS star catalogs are compared and the average difference in magnitude as a function of right ascension and declination exhibits small systematic errors in relative calibration. The photometric transformation from the SDSS Photometric Telescope to the 2.5 m telescope is recomputed and compared to synthetic magnitudes computed from measured filter bandpasses.

Marriner, John; /Fermilab

2012-06-29

89

Derivative analysis of potentiometric titration data to obtain protonation constants  

SciTech Connect

A methodology is described to calibrate glass electrodes and to analyze potentiometric titration data to calculate protonation constants. The analysis uses the variation of dV/dpH with titrant addition in terms of two physical parameters which involve the concentrations of H{sup +}, OH{sup -}, and H{sub m}A. The data for titration of acetic acid and 8-hydroxyquinoline in 0.10-5.0 m NaCl media are analyzed by this method to obtain the stoichiometric protonation constants of the acids, the ionization constants of water, and the parameters s and b in the pH electrode calibration equation, pcH = spH{sub m} + b, where pcH = -log[H{sup +}], pH{sub m} is the pH meter reading. 31 refs., 3 figs., 6 tabs.

Chen, J.F.; Xia, Y.X.; Choppin, G.R. [Florida State Univ., Tallahassee, FL (United States)] [Florida State Univ., Tallahassee, FL (United States)

1996-11-15

90

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

91

Solubility diagrams in solvent-antisolvent systems by titration calorimetry  

Microsoft Academic Search

Isothermal titration calorimetry (ITC) has been used to develop a method to construct the solid-liquid equilibrium line in\\u000a ternary systems containing the solute to precipitate and an aqueous mixed solvent. The method consists in measuring the heat\\u000a of dissolution of a solid component (the solute) during successive additions of the liquid solvent. The cumulated heat, resulting\\u000a from the successive heat

M. H. Hamedi; J.-P. E. Grolier

2007-01-01

92

Isopropyl alcohol as a solvent for free fatty acid titration  

Microsoft Academic Search

George H. Kyser of Barrow-Agee Laboratories, Inc., Cairo, Illinois, suggested the possibility of using Isopropyl Alcohol as\\u000a a substitute for Specially Denatured Alcohol, Formula No. 30, in the titration of free fatty acids in crude oil and in the\\u000a oil of cottonseed samples. This substitution would eliminate the necessity of special permits and bonds for the use of alcohol.\\u000a \\u000a Isopropyl

G. Worthen Agee

1938-01-01

93

New developments for the numerical analysis of spectrophotometric titrations  

Microsoft Academic Search

Spectrophotometric titrations are a valuable tool for the investigation of solution equilibria. Data acquisition and recent developments on methods for the analysis of the measurements are discussed in this contribution. Hard-modeling methods are based on non-linear least-squares fitting, and algorithms have been developed which can cope with the large amount of data and parameters of multiwavelength or multivariate measurements. Good

Raylene M. Dyson; Porn Jandanklang; Marcel Maeder; Caroline J. Mason; Andrew Whitson

1999-01-01

94

Depression May Reduce Adherence during CPAP Titration Trial  

PubMed Central

Study Objectives: Depression is a risk factor for medication non-compliance. We aimed to identify if depression is associated with poorer adherence during home-based autotitrating continuous positive airway pressure (autoPAP) titration. Design: Mixed retrospective-observational study. Setting: Academic center. Participants: Two-hundred forty continuous positive airway pressure-naïve obstructive sleep apnea (OSA) patients. Measurements: Patients underwent approximately 1 week of home-based autoPAP titration with adherence data downloaded from the device. Electronic hospital records were reviewed in a consecutive manner for inclusion. Three areas of potential predictors were examined: (i) demographics and clinical factors, (ii) disease severity, and (iii) device-related variables. Depression and anxiety were assessed using the Hospital Anxiety and Depression Scale (HADS). Scores on the subscales were categorized as normal or clinical diagnoses of depression (? 8) and anxiety (? 11). The primary outcome variable was the mean hours of autoPAP used per night. Results: Patients were diagnosed with OSA by either attended polysomnography (n = 73, AHI 25.5[15.1-41.5]) or unattended home oximetry (n = 167, ODI3 34.0[22.4-57.4]) and had home-based autoPAP titration over 6.2 ± 1.2 nights. Mean autoPAP use was 4.5 ± 2.4 hours per night. Multiple linear regression analysis revealed that depression and lower 95th percentile pressures significantly predicted lesser hours of autoPAP use (R2 = 0.19, p < 0.001). Significantly milder OSA in those requiring lower pressures may have confounded the relationship between 95th percentile pressure and autoPAP use. Conclusion: Depression was independently associated with poorer adherence during home-based autoPAP titration. Depression may be a potential target for clinicians and future research aimed at enhancing adherence to autoPAP therapy. Citation: Law M; Naughton M; Ho S; Roebuck T; Dabscheck E. Depression may reduce adherence during CPAP titration trial. J Clin Sleep Med 2014;10(2):163-169. PMID:24532999

Law, Mandy; Naughton, Matthew; Ho, Sally; Roebuck, Teanau; Dabscheck, Eli

2014-01-01

95

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

96

A Thermodynamic Study of Tin Oxides by Coulometric Titration  

NASA Astrophysics Data System (ADS)

The nonstoichiometries of tin oxides have been studied by coulometric titration, using solid state electrolytes (YSZ) between 694 K and 990 K. The nonstoichiometry( X) and the oxygen partial pressure ( Po 2) vary as x ? P-1/6o 2 mean 900 k. A phase Sn 3O 4 between the Sn and SnO 2 in the range of 969-732 k. The Gibbs free energy change of formation of Sn 3O 4 is given by ? GoSn 3O 4 = -1,163,960 + 417.36 T (J/mol).

Li-Zi, Yang; Zhi-Tong, Sui; Chan-Zheng, Wang

1994-12-01

97

Interaction between bisphenol A and tannic Acid: Spectroscopic titration approach  

NASA Astrophysics Data System (ADS)

The interaction between tannic acid (TA) and bisphenol A (BPA), an endocrine disruptor, was studied by absorption and fluorescence titration techniques. The binding constants and corresponding thermodynamic parameters at different temperatures (294, 296, 298, 300 and 303 K) were determined. The intrinsic fluorescence of BPA was strongly quenched by TA and the quenching mechanism is attributed to static quenching. The thermodynamic data revealed that the formation of TA-BPA complex was exothermic, entropic-driven, and spontaneous. Furthermore, hydrogen and van der Waals interactions seem to be the major driving forces for the formation of the nonfluorescent TA-BPA complex.

Omoike, Anselm; Brandt, Benjamin

2011-06-01

98

Isothermal Titration Calorimetry of Membrane Proteins – Progress and Challenges  

PubMed Central

Summary Integral membrane proteins, including G protein-coupled receptors (GPCR) and ion channels, mediate diverse biological functions that are crucial to all aspects of life. The knowledge of the molecular mechanisms, and in particular, the thermodynamic basis of the binding interactions of the extracellular ligands and intracellular effector proteins is essential to understand the workings of these remarkable nanomachines. In this review, we describe how isothermal titration calorimetry (ITC) can be effectively used to gain valuable insights into the thermodynamic signatures (enthalpy, entropy, affinity, and stoichiometry), which would be most useful for drug discovery studies, considering that more than 30% of the current drugs target membrane proteins. PMID:23747362

Rajarathnam, Krishna; Rösgen, Jörg

2013-01-01

99

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

NASA Astrophysics Data System (ADS)

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 KIO3 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.

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

2011-11-01

100

Photometric theory for wide-angle phenomena  

NASA Astrophysics Data System (ADS)

An examination is made of the problem posed by wide-angle photographic photometry, in order to extract a photometric-morphological history of Comet P/Halley. Photometric solutions are presently achieved over wide angles through a generalization of an assumption-free moment-sum method. Standard stars in the field allow a complete solution to be obtained for extinction, sky brightness, and the characteristic curve. After formulating Newton's method for the solution of the general nonlinear least-square problem, an implementation is undertaken for a canonical data set. Attention is given to the problem of random and systematic photometric errors.

Usher, P. D.

1990-07-01

101

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

102

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. PMID:24889139

Hu, Hao; Shen, Lin

2014-07-30

103

Photometric stereo without multiple images  

NASA Astrophysics Data System (ADS)

Photometric stereo (PMS) recovers orientation vectors from a set of graylevel images. Under orthography, when the lights are unknown, and for a single uniform Lambertian surface, one can recover surface normals up to an unknown overall orthogonal transformation. The same situation obtains if, instead of three graylevel images, one uses a single RGB image taken with at least three point or extended colored lights impinging on the surface at once. Then using a robust technique and the constraints among the resulting three effective lighting vectors one can recover effective lights as well as normals, with no unknown rotation. However, in the case of a non-Lambertian object, PMS reduces to the idea of using a lookup table (LUT) based on a calibration sphere. Here, we show that a LUT can also be used in the many-colored- lights paradigm, eliminating the need for three separate images as in standard PMS. As well, we show how to transform a calibration sphere made of a particular material into a theoretical sphere for a cognate material similar in its specular properties but of a different color. In particular, we postulate that a LUT developed from one human's skin can be used for any other person; problems arising from shadows, hair, eyes, etc. are automatically eliminated using robust statistics. Results are shown using both synthetic and real images.

Drew, Mark S.

1997-06-01

104

Photometric properties of Triton hazes  

NASA Technical Reports Server (NTRS)

Voyager imaging observations of Triton have been used to investigate the characteristics of the atmospheric hazes on Triton at three wavelengths: violet (0.41 micrometers), blue (0.48 micrometers), and green (0.56 micrometers). The globally averaged optical depth is wavelength dependent, varying from 0.034 in green to 0.063 in violet. These photometric results are dominated by the properties of localized discrete clouds rather than by those of the thinner, more widespread haze known to occur on Triton. The cloud particles are bright, with single-scattering albedos near unity at all three wavelengths, suggestive of a transparent icy condensate. The asymmetry parameter (+0.6) and the wavelength dependence of the optical depth both indicate cloud particles 0.2-0.4 micrometers in radius. The clouds are concentrated at 50-60 deg S latitude, where opacities up to three times the global average are observed. This is the same latitude region where most of the evidence for current surface activity is found, suggesting that the clouds may be related to the plumes or at least to some process connected with the sublimation of the south polar cap. The effects of possible temporal variations in the haze opacity are examined. Increases in the haze opacity tend to redden Triton. However, the degree of reddening is not sufficient to explain the full range of observed changed in Triton over the past decade; variations in the surface properties appear to be necessary.

Hillier, J.; Veverka, J.

1994-01-01

105

Neurons limit angiogenesis by titrating VEGF in retina.  

PubMed

Vascular and nervous systems, two major networks in mammalian bodies, show a high degree of anatomical parallelism and functional crosstalk. During development, neurons guide and attract blood vessels, and consequently this parallelism is established. Here, we identified a noncanonical neurovascular interaction in eye development and disease. VEGFR2, a critical endothelial receptor for VEGF, was more abundantly expressed in retinal neurons than in endothelial cells, including endothelial tip cells. Genetic deletion of VEGFR2 in neurons caused misdirected angiogenesis toward neurons, resulting in abnormally increased vascular density around neurons. Further genetic experiments revealed that this misdirected angiogenesis was attributable to an excessive amount of VEGF protein around neurons caused by insufficient engulfment of VEGF by VEGFR2-deficient neurons. Moreover, absence of neuronal VEGFR2 caused misdirected regenerative angiogenesis in ischemic retinopathy. Thus, this study revealed neurovascular crosstalk and unprecedented cellular regulation of VEGF: retinal neurons titrate VEGF to limit neuronal vascularization. PAPERFLICK: PMID:25417109

Okabe, Keisuke; Kobayashi, Sakiko; Yamada, Toru; Kurihara, Toshihide; Tai-Nagara, Ikue; Miyamoto, Takeshi; Mukouyama, Yoh-Suke; Sato, Thomas N; Suda, Toshio; Ema, Masatsugu; Kubota, Yoshiaki

2014-10-23

106

Enzymatic activity of immobilized enzyme determined by isothermal titration calorimetry.  

PubMed

The activity of adsorbed beta-glucosidase onto spherical polyelectrolyte brushes (SPBs) is investigated by UV-Vis spectroscopy and isothermal titration calorimetry (ITC). By comparing the results of these two methods, we demonstrate that ITC is a precise method for the study of the activity of immobilized enzymes. The carrier particles used for immobilization here consist of a polystyrene core onto which poly(acrylic acid) chains are grafted. High amounts of enzyme can be immobilized in the brush layer at low ionic strength by the polyelectrolyte-mediated protein adsorption (PMPA). Analysis of the activity of beta-glucosidase was done in terms of Michaelis-Menten kinetics. Moreover, the enzymatic activity of immobilized enzyme is studied by ITC using cellobiose as substrate. All data show that ITC is a general method for the study of the activity of immobilized enzymes. PMID:18440294

Henzler, Katja; Haupt, Björn; Ballauff, Matthias

2008-07-15

107

Characteristics of aversive thresholds measured by a titration schedule1  

PubMed Central

Three variables were studied for their single and joint effects on aversive thresholds obtained by a titration schedule with electric shock as the aversive stimulus. One variable was the interval between the periodic increments in shock amplitude. Another was the size of this increment. The third was the size of the decrement produced when the subject responded. Both monkeys and humans tolerated more shock at the shorter increment-to-increment intervals than at the longer ones, confirming rat data previously obtained. Reducing the decremental step size also led to an increase in the amount of shock tolerated by monkeys. In addition, simply reducing both incremental and decremental step size without changing the interval between increments led monkeys to tolerate more shock. The attempt to explain these data was based on the changes that such manipulations might produce in the amount of avoidance behavior elicited. PMID:14055954

Weiss, Bernard; Laties, Victor G.

1963-01-01

108

Standard test method for uranium by Iron (II) reduction in phosphoric acid followed by chromium (VI) titration in the presence of vanadium  

E-print Network

1.1 This test method, commonly referred to as the Modified Davies and Gray technique, covers the titration of uranium in product, fuel, and scrap materials after the material is dissolved. The test method is versatile and has been ruggedness tested. With appropriate sample preparation, this test method can give precise and unbiased uranium assays over a wide variety of material types (1, 2). Details of the titration procedure in the presence of plutonium with appropriate modifications are given in Test Method C1204. 1.2 Uranium levels titrated are usually 20 to 50 mg, but up to 200 mg uranium can be titrated using the reagent volumes stated in this test method. 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determ...

American Society for Testing and Materials. Philadelphia

2011-01-01

109

Spectro-photometric distances to stars: a general-purpose Bayesian approach  

E-print Network

We have developed a procedure that estimates distances to stars using measured spectroscopic and photometric quantities. It employs a Bayesian approach to build the probability distribution function over stellar evolutionary models given the data, delivering estimates of expected distance for each star individually. Our method provides several alternative distance estimates for each star in the output, along with their associated uncertainties. The code was first tested on simulations, successfully recovering input distances to mock stars with errors that scale with the uncertainties in the adopted spectro-photometric parameters, as expected. The code was then validated by comparing our distance estimates to parallax measurements from the Hipparcos mission for nearby stars (< 60 pc), to asteroseismic distances of CoRoT red giant stars, and to known distances of well-studied open and globular clusters. The photometric data of these reference samples cover both the optical and near infra-red wavelengths. The...

Santiago, Basílio X; Anders, Friedrich; Chiappini, Cristina; Girardi, Léo; Rocha-Pinto, Helio J; Balbinot, Eduardo; da Costa, Luiz N; Maia, Marcio A G; Schultheis, Mathias; Steinmetz, Matthias; Miglio, Andrea; Montalbán, Josefina; Schneider, Donald P; Beers, Timothy C; Frinchaboy, Peter M; Lee, Young Sun; Zasowski, Gail

2015-01-01

110

Impact of subsolar metallicities on photometric redshifts  

NASA Astrophysics Data System (ADS)

With the advent of deep photometric surveys the use of photometric redshifts, obtained with a variety of techniques, has become more and more widespread. Giving access to galaxies with a wide range of luminosities out to high redshifts, these surveys include many faint galaxies with significantly subsolar metallicities. We use our chemically consistent (CC) galaxy evolutionary synthesis code GALEV to produce a large grid of template spectral energy distributions (SEDs) for galaxies of spectral types E and Sa through Sd - one accounting in a CC way for the increasing initial metallicities of successive stellar generations, the other one for exclusively solar metallicities - for comparison. We use our new photometric redshift code GAZELLE based on the comparison of observed and model SEDs. Comparing the photometric redshifts obtained using solar-metallicity templates when working on a catalogue of artificially created CC SEDs, typical for low-metallicity local late-type galaxies and for intrinsically low-luminosity, and hence low-metallicity, galaxies in the high-redshift universe, we find a significant bias resulting from this metallicity mismatch. This bias consists of a systematic underestimate of the photometric redshift by typically ?z ~ 0.1...0.2 until z ~ 1.2, depending on galaxy type, of distant, faint and low-metallicity galaxies if analysed with solar-metallicity templates.

Kotulla, Ralf; Fritze, Uta

2009-02-01

111

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

112

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

113

The Sloan Digital Sky Survey Photometric Camera  

E-print Network

We have constructed a large format mosaic CCD camera for the Sloan Digital Sky Survey. The camera consists of two arrays, a photometric array which uses 30 2048 x 2048 SITe/Tektronix CCDs (24 micron pixels) with an effective imaging area of 720 square cm, and an astrometric array which uses 24 400 x 2048 CCDs with the same pixel size, which will allow us to tie bright astrometric standard stars to the objects imaged in the photometric camera. The instrument will be used to carry out photometry essentially simultaneously in five color bands spanning the range accessible to silicon detectors on the ground in the time-delay- and-integrate (TDI) scanning mode. The photometric detectors are arrayed in the focal plane in six columns of five chips each such that two scans cover a filled stripe 2.5 degrees wide. This paper presents engineering and technical details of the camera.

J. Gunn; M. Carr; C. Rockosi; M. Sekiguchi

1998-09-08

114

Dose titration of BAF312 attenuates the initial heart rate reducing effect in healthy subjects  

PubMed Central

Aim Previous studies have shown transient decreases in heart rate (HR) following administration of sphingosine 1?phosphate (S1P) receptor modulators including BAF312. This study was conducted to determine whether dose titration of BAF312 reduces or eliminates these effects. Methods Fifty?six healthy subjects were randomized 1:1:1:1 to receive BAF312 in one of two dose titration (DT) regimens (DT1 and DT2: 0.25–10?mg over 9–10?days), no titration (10?mg starting dose) or placebo. Pharmacodynamic and pharmacokinetic parameters were assessed. Results Neither DT1 nor DT2 resulted in clinically significant bradycardia or atrioventricular conduction effects. Both titration regimens showed a favourable difference on each of days 1–12 vs. the non?titration regimen on day 1 for HR effects (P < 0.0001). On day 1, the geometric mean ratio of the fraction from the previous day in minimum daily HR between DT1 and non?titration was 1.18 (95% confidence interval [CI] 1.13, 1.23) and 1.14 (95% CI 1.09, 1.18) for DT2 (both P < 0.05) with significant differences noted through to day 12. Non?titration HRs showed considerable separation from placebo throughout the study. There was no statistically significant reduction in HR vs. placebo on day?1 in either titration regimen. On days 3–7 subjects in DT1 and DT2 experienced minor reductions in HR vs. placebo (approximately 5?beats?min?1; P ? 0.0001). From days 9–12, HRs in both titration regimens were comparable with placebo. Conclusion Both titration regimens effectively attenuated the initial bradyarrhythmia observed on day 1 of treatment with BAF312 10?mg. PMID:22845008

Legangneux, Eric; Gardin, Anne; Johns, Donald

2013-01-01

115

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

116

Photometric diversity of terrains on Triton  

NASA Technical Reports Server (NTRS)

Voyager disk-resolved images of Triton in the violet (0.41 micrometers) and green (0.56 micrometer wavelengths have been analyzed to derive the photometric characteristics of terrains on Triton. Similar conclusions are found using two distinct but related definitions of photometric units, one based on color ratio and albedo properties (A. S. McEwen, 1990), the other on albedo and brightness ratios at different phase angles (P. Lee et al., 1992). A significant diversity of photometric behavior, much broader than that discovered so far on any other icy satellite, occurs among Triton's terrains. Remarkably, differences in photometric behavior do not correlate well with geologic terrain boundaries defined on the basis of surface morphology. This suggests that in most cases photometric properties on Triton are controlled by thin deposits superposed on underlying geologic units. Single scattering albedos are 0.98 or higher and asymmetry factors range from -0.35 to -0.45 for most units. The most distinct scattering behavior is exhibited by the reddish northern units already identified as the Anomalously Scattering Region (ASR), which scatters light almost isotropically with g = -0.04. In part due to the effects of Triton's clouds and haze, it is difficult to constrain the value of bar-theta, Hapke's macroscopic roughness parameter, precisely for Triton or to map differences in bar-theta among the different photometric terrains. However, our study shows that Triton must be relatively smooth, with bar-theta less than 15-20 degs and suggests that a value of 14 degs is appropriate. The differences in photometric characteristics lead to significantly different phase angle behavior for the various terrains. For example, a terrain (e.g., the ASR) that appears dark relative to another at low phase angles will reverse its contrast (become relatively brighter) at larger phase angles. The photometric parameters have been used to calculate hemispherical albedos for the units and to infer likely surface temperatures. Based on these results, we determine that all but the most southerly regions (i.e., mostly south of the equator) of the reddish northern terrains are likely to have been covered with deposits of nitrogen frost at the time of the Voyager flyby, in agreement with the suggestion from the photometry that these units are overlain by a thin veneer of material.

Hillier, J.; Veverka, J.; Helfenstein, P.; Lee, P.

1994-01-01

117

Probing lectin-mucin interactions by isothermal titration microcalorimetry.  

PubMed

Isothermal titration microcalorimetry (ITC) can directly determine the thermodynamic binding parameters of biological molecules including affinity constant, binding stoichiometry, and heat of binding (enthalpy) and indirectly the entropy and free energy of binding. ITC has been extensively used to study the binding of lectins to mono- and oligosaccharides, but limited applications to lectin-glycoprotein interactions. Inherent experimental challenges to ITC include sample precipitation during the experiment and relative high amount of sample required, but careful design of experiments can minimize these problems and allow valuable information to be obtained. For example, the thermodynamics of binding of lectins to multivalent globular and linear glycoproteins (mucins) have been described. The results are consistent with a dynamic binding mechanism in which lectins bind and jump from carbohydrate to carbohydrate epitope in these molecules leading to increased affinity. Importantly, the mechanism of binding of lectins to mucins appears similar to that for a variety of protein ligands binding to DNA. Recent results also show that high affinity lectin-mucin cross-linking interactions are driven by favorable entropy of binding that is associated with the bind and jump mechanism. The results suggest that the binding of ligands to biopolymers, in general, may involve a common mechanism that involves enhanced entropic effects that facilitate binding interactions. PMID:25253134

Dam, Tarun K; Brewer, C Fred

2015-01-01

118

Characterization of membrane protein interactions by isothermal titration calorimetry.  

PubMed

Understanding the structure, folding, and interaction of membrane proteins requires experimental tools to quantify the association of transmembrane (TM) helices. Here, we introduce isothermal titration calorimetry (ITC) to measure integrin ?IIb?3 TM complex affinity, to study the consequences of helix-helix preorientation in lipid bilayers, and to examine protein-induced lipid reorganization. Phospholipid bicelles served as membrane mimics. The association of ?IIb?3 proceeded with a free energy change of -4.61±0.04kcal/mol at bicelle conditions where the sampling of random helix-helix orientations leads to complex formation. At bicelle conditions that approach a true bilayer structure in effect, an entropy saving of >1kcal/mol was obtained from helix-helix preorientation. The magnitudes of enthalpy and entropy changes increased distinctly with bicelle dimensions, indicating long-range changes in bicelle lipid properties upon ?IIb?3 TM association. NMR spectroscopy confirmed ITC affinity measurements and revealed ?IIb?3 association and dissociation rates of 4500±100s(-1) and 2.1±0.1s(-1), respectively. Thus, ITC is able to provide comprehensive insight into the interaction of membrane proteins. PMID:25178257

Situ, Alan J; Schmidt, Thomas; Mazumder, Parichita; Ulmer, Tobias S

2014-10-23

119

Predicting proton titration in cationic micelle and bilayer environments  

NASA Astrophysics Data System (ADS)

Knowledge of the protonation behavior of pH-sensitive molecules in micelles and bilayers has significant implications in consumer product development and biomedical applications. However, the calculation of pKa's in such environments proves challenging using traditional structure-based calculations. Here we apply all-atom constant pH molecular dynamics with explicit ions and titratable water to calculate the pKa of a fatty acid molecule in a micelle of dodecyl trimethylammonium chloride and liquid as well as gel-phase bilayers of diethyl ester dimethylammonium chloride. Interestingly, the pKa of the fatty acid in the gel bilayer is 5.4, 0.4 units lower than that in the analogous liquid bilayer or micelle, despite the fact that the protonated carboxylic group is significantly more desolvated in the gel bilayer. This work illustrates the capability of all-atom constant pH molecular dynamics in capturing the delicate balance in the free energies of desolvation and Coulombic interactions. It also shows the importance of the explicit treatment of ions in sampling the protonation states. The ability to model dynamics of pH-responsive substrates in a bilayer environment is useful for improving fabric care products as well as our understanding of the side effects of anti-inflammatory drugs.

Morrow, Brian H.; Eike, David M.; Murch, Bruce P.; Koenig, Peter H.; Shen, Jana K.

2014-08-01

120

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

121

Misuse of thermodynamics in the interpretation of isothermal titration calorimetry data for ligand binding to proteins.  

PubMed

Isothermal titration calorimetry (ITC) has given a mass of data on the binding of small molecules to proteins and other biopolymers, with particular interest in drug binding to proteins chosen as therapeutic indicators. Interpretation of the enthalpy data usually follows an unsound protocol that uses thermodynamic relations in circumstances where they do not apply. Errors of interpretation include incomplete definitions of ligand binding and equilibrium constants and neglect of the non-ideality of the solutions under study, leading to unreliable estimates of standard free energies and entropies of binding. The mass of reported thermodynamic functions for ligand binding to proteins estimated from ITC enthalpies alone is consequently of uncertain thermodynamic significance and utility. ITC and related experiments to test the protocol assumptions are indicated. A thermodynamic procedure avoiding equilibrium constants or other reaction models and not requiring protein activities is given. The discussion draws attention to the fundamental but neglected relation between the thermodynamic activity and bioactivity of drugs and to the generally unknown thermodynamic status of ligand solutions, which for drugs relates directly to effective therapeutic dosimetry. PMID:25484232

Pethica, Brian A

2015-03-01

122

Simultaneous determination of delta G, delta H and delta S by an automatic microcalorimetric titration technique. Application to protein ligand binding.  

PubMed

A methodological study has been made with a syringe titration unit attached to an LKB batch microcalorimeter. The precision and accuracy of the instrument assembly have been evaluated by neutralization reactions and by dilution of sucrose solutions. As an example, heat quantities on the order of 10 mJ accompanying the addition of 10 microliter titrant solution could be determined with an accuracy of better than 1%. A stepwise titration procedure was used to characterize the binding of indole-3-propionic acid to alpha-chymotrypsin. The following thermodynamic data were obtained (25 degrees C, acetate buffer, pH 5.80): delta G0=-18.46 +/- 0.17 kJ X mol-1, delta H0=-15.26 +/- 0.20 kJ X mol-1, delta S0 = 10.85 +/- 1.21 JK-1 X mol-1. PMID:7142659

Chen, A; Wadsö, I

1982-09-01

123

The titration of the active centers of cellobiohydrolase from Trichoderma reesei.  

PubMed

A novel approach has been developed for the titration of enzyme active centers and for the determination of the molecular activity of enzymes. It is based on the simultaneous use of a nonspecific chromogenic substrate and a specific ligand (a substrate or an inhibitor), the latter being tightly bound with the enzyme's active center. The approach is demonstrated using the titration (that is, the determination of the molar concentration of the enzyme active centers) of purified cellobiohydrolase I (CBH I) (EC 3.2.1.91) of the fungus Trichoderma reesei. p-Nitrophenyl-beta-D-lactoside was used as a reference substrate (Km = 0.5 mM), and cellobiose and CM-cellulose as specific ligands. The molecular weight of CBH I as it was determined by the titration with cellobiose was 42,000 +/- 3,000. The inhibition constant by cellobiose was (6 +/- 1) X 10(-6) M. The value of the catalytic constant for the hydrolysis of p-nitrophenyl-beta-D-lactoside calculated from the titration data was equal to 0.063 s-1. CM-cellulose turned out to be more efficient titration agent for cellobiohydrolase than cellobiose, and might be used for the titration of the enzyme in concentrations of the latter of 0.008-0.02 mg/ml. The titration data showed that the inhibition constant of CM-cellulose toward CBH I was equal to (1.0 +/- 0.2) X 10(-7) M. PMID:3766948

Rabinowitch, M L; Klyosov, A A; Melnick, M S

1986-08-01

124

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

125

Passive Photometric Stereo from Motion Jongwoo Lim  

E-print Network

of Florida 800 California St University of California Urbana, IL 61801 Gainesville, FL 32611 Mountain View perspectives over the years, and two of which directly related to our work are multi-view stereo (e.g., [5]) and photometric stereo (e.g., [16]). From multi- view stereo, we know how to recover the 3D position of a scene

Jaffe, Jules

126

A photometric perturbation of the counterglow.  

NASA Technical Reports Server (NTRS)

An example of photometric variability of a counterglow region in the antisolar direction is discussed. A speculative interpretation of its significance leads to the suggestion that the weakened radiance of the counterglow may in this case be due to a dust cloud of scattering material in the general region of the earth-moon system.

Roach, F. E.; Carroll, B.; Roach, J. R.; Aller, L. H.

1973-01-01

127

A photometric model of the zodiacal light.  

NASA Technical Reports Server (NTRS)

An intercomparison of published photometric investigations of the zodiacal light and gegenschein is made, leading to a compilation of brightnesses over the entire sky in a reseau with 5-deg intervals. The results are given in absolute units. Several graphical representations illustrate the compilation.

Roach, F. E.

1972-01-01

128

Standard Photometric Systems Michael S. Bessell  

E-print Network

: photometric,spectroscopic catalogs. ABSTRACT: Standard star photometry dominated the second part of the 20th and accuracy of much broad and inter- mediate band photometry su ered until more suitable observational photometry will be outlined and the calibration and realization of standard systems will be examined. Finally

Harrison, Thomas

129

Adaptive Image Segmentation by Combining Photometric Invariant  

E-print Network

Adaptive Image Segmentation by Combining Photometric Invariant Region and Edge Information Theo Gevers, Member, IEEE AbstractÐAn adaptive image segmentation scheme is proposed employing the Delaunay robustness. æ 1 INTRODUCTION IN this paper, image segmentation is considered as the process of partitioning

Gevers, Theo

130

Isothermal titration calorimetry in nanoliter droplets with subsecond time constants.  

PubMed

We reduced the reaction volume in microfabricated suspended-membrane titration calorimeters to nanoliter droplets and improved the sensitivities to below a nanowatt with time constants of around 100 ms. The device performance was characterized using exothermic acid-base neutralizations and a detailed numerical model. The finite element based numerical model allowed us to determine the sensitivities within 1% and the temporal dynamics of the temperature rise in neutralization reactions as a function of droplet size. The model was used to determine the optimum calorimeter design (membrane size and thickness, junction area, and thermopile thickness) and sensitivities for sample volumes of 1 nL for silicon nitride and polymer membranes. We obtained a maximum sensitivity of 153 pW/(Hz)(1/2) for a 1 ?m SiN membrane and 79 pW/(Hz)(1/2) for a 1 ?m polymer membrane. The time constant of the calorimeter system was determined experimentally using a pulsed laser to increase the temperature of nanoliter sample volumes. For a 2.5 nanoliter sample volume, we experimentally determined a noise equivalent power of 500 pW/(Hz)(1/2) and a 1/e time constant of 110 ms for a modified commercially available infrared sensor with a thin-film thermopile. Furthermore, we demonstrated detection of 1.4 nJ reaction energies from injection of 25 pL of 1 mM HCl into a 2.5 nL droplet of 1 mM NaOH. PMID:21913688

Lubbers, Brad; Baudenbacher, Franz

2011-10-15

131

Circular dichroism-inhibitor titrations of arsanilazotyrosine-248 carboxypeptidase A.  

PubMed

Coupling of carboxypeptidase with diazotized arsanilic acid specifically modifies a single tyrosyl residue. Yet, owing to the fact that the resultant azoTyr-248 can form an intramolecular chelate with zinc, two different circular dichroism probes result: azoTyr-248 itself and the azoTyr-248-Zn chelate. Both are environmentally sensitive and, characteristically, each can signal the same or different perturbations, as is apparent from circular dichroic spectra. This dual probe function greatly magnifies the scope of these chromophores in mapping the topography of the active center with respect to sites of interaction of inhibitors (or substrates). Titration of the azoenzyme with a series of synthetic, competitive inhibitors, e.g., L-benzylsuccinate, L-phenyllactate, and L-Phe, and with the pseudosubstrate, Gly-L-Tyr, in turn generates characteristic circular dichroic spectra. Their analysis yields a single binding constant for each of these agents, one molecule of each binding to the active center. Mixed inhibitions, as seen with beta-phenylpropionate and phenylacetate, resolved previously into competitive and noncompetitive components, are characterized by different spectral effects. Two molecules of these agents bind to the enzyme, consistent with both thermodynamic and enzymatic studies. The interactions leading to competitive and noncompetitive inhibition, respectively, can be recognized and assigned, based on the manner in which the extrema at 340 and 420 nm, reflecting azoTyr-248, and the negative 510-nm circular dichroism band, typical of its chelate with zinc, are affected and on the pH dependence of spectral and kinetic data. Certai4 noncompetitive inhibitors and modifiers induce yet other spectral features. Each probe is very sensitive to changes in its particular active center environment, though both can be relatively insensitive to inhibitors interacting at a distance from the active center. PMID:1247518

Johansen, J T; Klyosov, A A; Vallee, B L

1976-01-27

132

Determining a Depth Map Using a Dual Photometric Stereo  

Microsoft Academic Search

This paper describes a method for determining a depth map from a pair of surface-orientation maps obtained by a dual photometric stereo. A photometric stereo system determines surface orientations by taking three images from the same position under different lighting conditions, based on the shading information. A photometric stereo system can deter mine surface orientations very rapidly, but cannot determine

Katsushi Ikeuchi

1987-01-01

133

A PHOTOMETRIC MODEL OF THE INCLINED F RING OF SATURN  

E-print Network

create a photometric model of the ring system with the F ring inclined to the main ring plane which reA PHOTOMETRIC MODEL OF THE INCLINED F RING OF SATURN A Dissertation Presented to the Faculty RESERVED #12;A PHOTOMETRIC MODEL OF THE INCLINED F RING OF SATURN Britt Rebecca Scharringhausen, Ph

Richardson Jr., James E.

134

40 CFR Appendix A to Part 425 - Potassium Ferricyanide Titration Method  

Code of Federal Regulations, 2014 CFR

...Sulfite interferes and must be precipitated with barium chloride. Thiosulfate is not titrated under the...stoppered container. 4. Preparation of 0.05M barium chloride solution: Dissolve 12-13 g. barium chloride dihydrate in 1 liter of...

2014-07-01

135

Amperometric titration of mercury with a stationary platinum electrode in stirred solutions.  

PubMed

Amperometric titration of mercury (in the range of 0-4 to 3.5 mg) has been carried out with 2-mercaptobenzoxazole with a stationary electrode in stirred solution in a sodium acetate-acetic acid medium. PMID:18959909

Bera, B C; Chakrabartty, M M; Bag, S P; Mallik, K L

1966-03-01

136

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

137

telomeric DNA (17). It is possible that the extra telomeric sequences in ALT cells are titrating  

E-print Network

telomeric DNA (17). It is possible that the extra telomeric sequences in ALT cells are titrating locus (the clark kent alleles) are associated with dense hypermethylation at noncanonical cytosines (Cp

Jacobsen, Steve

138

Investigation of moisture and acids in nonaqueous mixtures by means of high frequency titration methods  

E-print Network

in kOeten?, ~ ? ~ ? i ? ~ ~ ??? 80 V? Titration of Benaonoaolfonio 405d in kootono? ~ ??? ~ ? ~ 83 I VX, Titration of o?VhthaXie kog in keatone?, ?, ???, ?, ? 85 VXX? Titration of Water in koetono i ~ ??? ~ ~ i ?? q ~ ~ ?? 8V vlxI, Titrat1om of R..., T?RLTIOI Ot lEN@SR@L@lHXO 40?D Sf kgZNSE 5?00 RiOg003@8? '85?O WO?5 VX?5' '5. so '1?lo V?50 W9?0 , 54 5 ?55?O W8?O '5l?O 8?00 I 8?50 54?O &5?0 aa, s 0864 ~ iO ee. . ~eae~ani0. 'aorta 0. 0845 a f l Oo00 loCO 9o00 5o 00 4o00...

Turner, Vester Lamar

2012-06-07

139

Journal of Electroanalytical Chemistry 512 (2001) 8391 Faradaic impedance titration of pure 3-mercaptopropionic acid  

E-print Network

Journal of Electroanalytical Chemistry 512 (2001) 83­91 Faradaic impedance titration of pure 3-mercaptopropionic acid and ethanethiol mixed monolayers on gold Kyuwon Kim, Juhyoun Kwak * Department of Chemistry

Kwak, Juhyoun

140

Expenditures Associated with Dose Titration At Initiation of Therapy in Patients With Major Depressive Disorder  

PubMed Central

Objective. Although selective serotonin reuptake inhibitors (SSRIs) are considered cost-effective medications for patients with major depressive disorder (MDD), significant dosage adjustments are often necessary when treatment is initiated. Our study was conducted to examine whether dose titration for SSRIs at initiation of therapy was associated with a greater use of health care resources and higher costs. Study Design. A retrospective database analysis was conducted. Methods. A nationally representative cohort of individuals with MDD was identified in a large managed care claims database between January 1, 2004, and December 31, 2006. A study-specific titration algorithm was used to identify patients who underwent dose titration, compared with those who did not, within the first eight weeks of initiating SSRI therapy. We calculated propensity scores and identified a 1:1 matched cohort of titration versus non-titration patients. We used univariate and multivariate statistical tests to compare the mean number of therapeutic days, health care service utilization, and expenditures between the two groups during the first eight weeks (56 days) of treatment and six months (180 days) after treatment began. Results. Over the first eight weeks, the titration cohort had a 32% decrease in the adjusted mean number of therapeutic days (38 vs. 56, respectively; P < 0.001), a 50% increase in depression-related outpatient visits (1.8 vs. 1.2; P < 0.001), a 38% increase in depression-related outpatient costs ($137 vs. $81; P ? 0.001), an increase in antidepressant pharmacy costs ($139 vs. $61; P < 0.001), and a 64% increase in psychiatric visits (0.69 vs. 0.42; P = 0.001), compared with the matched non-titration cohort. These differences were consistent among individual SSRI groups as well as during the six-month period. Conclusion. Patients undergoing dose titration of SSRIs at the beginning of therapy consumed more medical resources and spent more days receiving a subtherapeutic dose than a comparable control group without dose titration. Differences in the utilization of resources were consistent with increased patient monitoring in the titration group; however, the added benefit of titration could not be assessed with this database. PMID:20844695

Camacho, Fabian; Kong, Meg C.; Sheehan, David V.; Balkrishnan, Rajesh

2010-01-01

141

Conductometric and pHmetric titrations of Extremely Diluted Solutions using HCl solutions as titrant  

Microsoft Academic Search

We carried out conductometric titrations of Extremely Diluted Solutions (EDS), obtained through an iterative process of successive dilutions and agitations. The aim of our investigations was to gain information on whether the agitation\\/dilution processes could produce non-equilibrium changes in the supramolecular structure of water and aqueous solutions. The titrations were performed by adding HCl solutions at concentrations between 1·10?4 and

C. M. Cacace; L. Elia; V. Elia; E. Napoli; M. Niccoli

2009-01-01

142

High school students' understanding of titrations and related acid- base phenomena  

Microsoft Academic Search

Acid-base titrations are common laboratory activities carried out in high school chemistry courses. Using a series of qualitative and computer-based tasks, this study examined sixteen American students' understanding of titrations. The findings indicated that students had considerable difficulty with acid-base chemistry, were unable to describe accurately acid-base concepts, such as pH, neutralization, strength, and the theoretical descriptions of acids and

Keith Sheppard

143

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. PMID:22114625

Dale, Eric; Ashby, Fleur; Seelam, Kalyan

2009-01-01

144

Unusual properties of crocodilian ovomacroglobulin shown in its methylamine treatment and sulfhydryl titration  

SciTech Connect

The inhibitory activity of chicken and crocodilian ovomacroglobulins against trypsin was measured before and after their incubation with methylamine. The result for crocodilian ovomacroglobulin showed that methylamine treatment destroyed half of its activity, in unique contrast to human alpha 2-macroglobulin and chicken ovomacroglobulin for which methylamine either destroys the inhibitory activity of the former completely or does not affect that of the latter at all. Free sulfhydryl groups of chicken and crocodilian ovomacroglobulins were titrated with 5,5'-dithiobis(2-nitrobenzoic acid) before and after incubation with trypsin. Prior to the incubation with trypsin the chicken and crocodilian proteins respectively had 0 and 1 titratable sulfhydryl per molecule of Mr 720,000. After treatment with trypsin the crocodilian protein had 3.5-4 titratable sulfhydryls, whereas there were no titratable sulfhydryls in the chicken protein. After denaturation of the crocodilian protein in sodium dodecyl sulfate at 100 degrees C the number of titratable sulfhydryls was 4. Chicken ovomacroglobulin again did not have an appreciable number of titratable sulfhydryls under similar denaturing conditions. Incubation of crocodilian protein with (14C)methylamine showed an incorporation of at least 2 mol of methylamine per molecule. The result indicated the presence of three intramolecular thiol ester bonds in crocodilian ovomacroglobulin with differential stability against external perturbations.

Arakawa, H.; Osada, T.; Ikai, A.

1986-02-01

145

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

146

Photometric reverberation mapping of active galactic nuclei  

NASA Astrophysics Data System (ADS)

Photometric reverberation mapping is a novel method used to determine the size and geometry of the broad line region (BLR) in active galactic nuclei (AGN) as well as their host galaxy free luminosities. Establishing a tight luminosity - BLR-size relation may allow type-1 AGN to be used as cosmological distance probes. However, the quality of the results is most sensible to dense time sampling and continuity of the photometric lightcurves. This demands an observatory, with optimal environmental conditions, like the "Universitätssternwarte Bochum", located in the Atacama Desert in Chile. The massive amount of observations are controlled robotically, adapting observational schedules of the telescopes to the weather conditions. Here we present one of the first promising results of our studies.

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

2014-12-01

147

The Sloan Digital Sky Survey Photometric Camera  

Microsoft Academic Search

We have constructed a large-format mosaic CCD camera for the Sloan Digital Sky Survey. The camera consists of two arrays, a photometric array that uses 30 2048 x 2048 SITe\\/Tektronix CCDs (24 mum pixels) with an effective imaging area of 720 cm^2 and an astrometric array that uses 24 400 x 2048 CCDs with the same pixel size, which will

J. E. Gunn; M. Carr; C. Rockosi; M. Sekiguchi; K. Berry; B. Elms; E. de Haas; Z. Ivezic; G. Knapp; R. Lupton; G. Pauls; R. Simcoe; R. Hirsch; D. Sanford; S. Wang; D. York; F. Harris; J. Annis; L. Bartozek; W. Boroski; J. Bakken; M. Haldeman; S. Kent; S. Holm; D. Holmgren; D. Petravick; A. Prosapio; R. Rechenmacher; M. Doi; M. Fukugita; K. Shimasaku; N. Okada; C. Hull; W. Siegmund; E. Mannery; M. Blouke; D. Heidtman; D. Schneider; R. Lucinio; J. Brinkman

1998-01-01

148

EAZY: A Fast, Public Photometric Redshift Code  

NASA Astrophysics Data System (ADS)

We describe a new program for determining photometric redshifts, dubbed EAZY. The program is optimized for cases where spectroscopic redshifts are not available, or are only available for a biased subset of the galaxies. The code combines features from various existing codes: it can fit linear combinations of templates, it includes optional flux- and redshift-based priors, and its user interface is modeled on the popular HYPERZ code. A novel feature is that the default template set, as well as the default functional forms of the priors, are not based on (usually highly biased) spectroscopic samples, but on semianalytical models. Furthermore, template mismatch is addressed by a novel rest-frame template error function. This function gives different wavelength regions different weights, and ensures that the formal redshift uncertainties are realistic. We introduce a redshift quality parameter, Qz, which provides a robust estimate of the reliability of the photometric redshift estimate. Despite the fact that EAZY is not ''trained'' on spectroscopic samples, the code (with default parameters) performs very well on existing public data sets. For K-selected samples in CDF-South and other deep fields, we find a 1 ? scatter in ?z/(1+z) of 0.034, and we provide updated photometric redshift catalogs for the FIRES, MUSYC, and FIREWORKS surveys.

Brammer, Gabriel B.; van Dokkum, Pieter G.; Coppi, Paolo

2008-10-01

149

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

150

The Sloan Digital Sky Survey Photometric Camera  

SciTech Connect

We have constructed a large-format mosaic CCD camera for the Sloan Digital Sky Survey. The camera consists of two arrays, a photometric array that uses 30 2048 {times} 2048 SITe/Tektronix CCDs (24 {mu}m pixels) with an effective imaging area of 720 cm{sup 2} and an astrometric array that uses 24 400 {times} 2048 CCDs with the same pixel size, which will allow us to tie bright astrometric standard stars to the objects imaged in the photometric camera. The instrument will be used to carry out photometry essentially simultaneously in five color bands spanning the range accessible to silicon detectors on the ground in the time-delay{endash}and{endash}integrate (TDI) scanning mode. The photometric detectors are arrayed in the focal plane in six columns of five chips each such that two scans cover a filled stripe 2&arcdeg;5 wide. This paper presents engineering and technical details of the camera. {copyright} {ital {copyright} 1998.} {ital The American Astronomical Society}

Gunn, J.E. [ (United States)] [(United States); Carr, M. [Princeton University Observatory, Princeton, NJ 08544 (United States)] [Princeton University Observatory, Princeton, NJ 08544 (United States); Rockosi, C. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States)] [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Sekiguchi, M. [Institute for Cosmic Ray Research, University of Tokyo, Tanashi, Tokyo 188 (Japan)] [Institute for Cosmic Ray Research, University of Tokyo, Tanashi, Tokyo 188 (Japan); Berry, K.; Elms, B.; de Haas, E.; Ivezic, Z.; Knapp, G.; Lupton, R.; Pauls, G.; Simcoe, R. [Department of Astrophysical Sciences and Princeton University Observatory, Peyton Hall, Princeton, NJ 08544 (United States)] [Department of Astrophysical Sciences and Princeton University Observatory, Peyton Hall, Princeton, NJ 08544 (United States); Hirsch, R.; Sanford, D.; Wang, S.; York, D. [Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States)] [Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Harris, F. [US Naval Observatory, Flagstaff Station, P.O. Box 1149, Flagstaff, AZ 86002 (United States)] [US Naval Observatory, Flagstaff Station, P.O. Box 1149, Flagstaff, AZ 86002 (United States); Annis, J.; Bartozek, L.; Boroski, W.; Bakken, J.; Haldeman, M.; Kent, S.; Holm, S.; Holmgren, D.; Petravick, D.; Prosapio, A.; Rechenmacher, R. [Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States)] [Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States); Doi, M. [Department of Astronomy, University of Tokyo, Hongo, Tokyo 113 (Japan)] [Department of Astronomy, University of Tokyo, Hongo, Tokyo 113 (Japan); Fukugita, M. [Institute for Cosmic Ray Research, University of Tokyo, Tanashi, Tokyo 188 (Japan)] [Institute for Advanced Study, Princeton, NJ 08540 (United States)] [Institute for Cosmic Ray Research, University of Tokyo, Tanashi, Tokyo 188 (Japan); Institute for Advanced Study, Princeton, NJ 08540 (United States); Shimasaku, K. [Department of Astronomy, University of Tokyo, Hongo, Tokyo 113 (Japan)] [Department of Astronomy, School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113 (Japan)] [Department of Astronomy, University of Tokyo, Hongo, Tokyo 113 (Japan); Department of Astronomy, School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113 (Japan); Okada, N. [National Astronomical Observatory, Mitaka, Tokyo 181 (Japan)] [National Astronomical Observatory, Mitaka, Tokyo 181 (Japan); Hull, C.; Siegmund, W.; Mannery, E. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States)] [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Blouke, M.; Heidtman, D. [Scientific Imaging Technologies, Inc., P.O. Box 569, Beaverton, OR 97075-0569 (United States)] [Scientific Imaging Technologies, Inc., P.O. Box 569, Beaverton, OR 97075-0569 (United States); Schneider, D. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States)] [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Lucinio, R.; and others

1998-12-01

151

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

152

Photometric variability of the Pre-Main sequence stars  

NASA Astrophysics Data System (ADS)

The photometric and spectral studies of the pre-main sequence stars are very important for understanding of the early stages of stellar evolution. Depending of the initial mass the young stars pass through different periods of stellar activity. The most prominent manifestations of this activity are changes in the star brightness with different periods and amplitudes.A short review on photometric variability of young stellar objects is presented in the paper. The physical mechanisms raising the photometric variability were summarized according to the main types of pre-main sequence stars. The importance of photometric and spectral observations of young variable stars with small telescopes is discussed.

Semkov, Evgeni H.

153

An on-line potentiometric sequential injection titration process analyser for the determination of acetic acid.  

PubMed

An on-line potentiometric sequential injection titration process analyser for the determination of acetic acid is proposed. A solution of 0.1 mol L(-1) sodium chloride is used as carrier. Titration is achieved by aspirating acetic acid samples between two strong base-zone volumes into a holding coil and by channelling the stack of well-defined zones with flow reversal through a reaction coil to a potentiometric sensor where the peak widths were measured. A linear relationship between peak width and logarithm of the acid concentration was obtained in the range 1-9 g/100 mL. Vinegar samples were analysed without any sample pre-treatment. The method has a relative standard deviation of 0.4% with a sample frequency of 28 samples per hour. The results revealed good agreement between the proposed sequential injection and an automated batch titration method. PMID:12207255

van Staden, J F; Mashamba, Mulalo G; Stefan, Raluca I

2002-09-01

154

[Research on determination of chemical purity of andrographolide by coulometric titration method].  

PubMed

The determination of chemical purity of andrographolide by coulometric titration method is studied in this paper. The coulometric titration was carried out in a mixture composed of 4 mol x L(-1) hydrochloric acid and 1 mol x L(-1) potassium bromide solution and 1 mol x L(-1) potassium nitrate solution (1:1). Bromine is electrogenerated at the anode and reacts with the andrographolide. The number of electrons involved in the eleatrode reaction is 2. Purity of andrographolide is 99.76% compared with 99.77% utilizing area normalization method by HPLC. The RSD are 0.33% and 0.02% respectively. The results from two methods are consistent, so the determination of chemical purity of andrographolide by coulometric titration method is scientific and feasible. The method is rapid, simple, convenient, sensitive and accurate. The reference material is not essential in the method. The method is suitable for determination of chemical purity of andrographolide. PMID:20617683

Yang, Ning; Yang, Dezhi; Xu, Lishen; Lv, Yang

2010-04-01

155

Potentiometric titration of Co(II) in presence of Co(III).  

PubMed

A potentiometric titration for cobalt(II) determination in the presence of Co(III) based on the oxidation of Co(II) with Na(2)CrO(4) in ethylenediamine medium and back-titration of the oxidant excess with (NH(4))(2)Fe(SO(4))(2) in acid medium is described. The titration is monitored with a Pt indicator electrode and carried out until the greatest jump of potential from one drop of titrant appears. A RSD smaller than 1.5% has been obtained for 50-300 mumol Co(II). The method proposed was applied in the analysis of a new type electroless copper plating solutions containing Co(II)-ethylenediamine complex compounds as reducing agents. Cu(II), Co(III) and Cr(III) do not interfere in the determination of Co(II). PMID:18967436

Norkus, E

1998-12-01

156

[Titration curves of beta-lactamases using pH gradient electrophoresis].  

PubMed

The molecular relationships of two types of plasmid-mediated beta-lactamases, TEM-1 (R 111), TEM-2 (RP 4) and OXA-1 (RGN 238), OXA-4 (pMG 90) were analysed by combined isoelectrofocusing-electrophoresis. Titration curves of TEM-1 (pI 5.4) and TEM-2 (pI 5.6) together were consistent with the known substitution of a glutamic acid in the former by a lysin in the latter. When OXA-1 (pI 7.4) and OXA-4 (pI 7.45) were titrated, one single mobility curve was obtained reflecting their structural homogeneity. The titration curve technique will be usefull for the study of structure of beta-lactamases. PMID:3116487

Vedel, G; Picard, B; Paul, G; Philippon, A; Goullet, P; Névot, P

1987-06-01

157

The Strömvil Photometric System: 1996 - 2006  

NASA Astrophysics Data System (ADS)

A group of astronomers has been working on setting up and then using the Strömvil photometric system. The system was announced in Straižys et al. (1996). A summary of the work up to 2003 can be found in Sodžius et al. (2003). The major ability of the Strömvil system is that, from photoelectric measures alone one can determine the reddening, luminosity, gravity and metalicity of stars. With all the new surveys that have been made and ones yet to be made, such a system will be of great use to identify the nature of the new faint stars identified. In 2012 GAIA is planned to be launched. It will make astrometric, spectroscopic and photometric measures of hundreds of millions of stars. It has a narrow band filter system of 14 filters, seven of which are very similar to the Strömvil filters.The main observational programs at present are: 1. Setting up the primary standards. Lithuanian astronomers have been sent to Arizona to use University of Arizona telescopes on Mt. Lemmon. A list of 800 Northern Hemisphere standard stars has been published in Baltic Astronomy (Kazlauskas et al. 2005). 2: At the Vatican Advanced Technology Telescope on Mt. Graham Boyle and Philip have been making CCD Strömvil measures of open and globular clusters. 3: At Casleo, in Argentina, Philip and Pintado have been observing open and globular clusters with the 2.15 meter telescope.

Philip, A. G. D.

2006-06-01

158

Using isothermal titration calorimetry to determine thermodynamic parameters of protein-glycosaminoglycan interactions.  

PubMed

It has now become increasingly clear that a complete atomic description of how biomacromolecules recognize each other requires knowledge not only of the structures of the complexes but also of how kinetics and thermodynamics drive the binding process. In particular, such knowledge is lacking for protein-glycosaminoglycan (GAG) complexes. Isothermal titration calorimetry (ITC) is the only technique that can provide various thermodynamic parameters-enthalpy, entropy, free energy (binding constant), and stoichiometry-from a single experiment. Here we describe different factors that must be taken into consideration in carrying out ITC titrations to obtain meaningful thermodynamic data of protein-GAG interactions. PMID:25325962

Dutta, Amit K; Rösgen, Jörg; Rajarathnam, Krishna

2015-01-01

159

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

160

The properties of cataclysmic variables in photometric Halpha surveys  

Microsoft Academic Search

We report on the properties of 71 known cataclysmic variables (CVs) in photometric Halpha emission-line surveys. Our study is motivated by the fact that the Isaac Newton Telescope (INT) Photometric Halpha Survey of the northern galactic plane (IPHAS) will soon provide r',i' and narrow-band Halpha measurements down to r' ~= 20 for all northern objects between - 5° < b

A. R. Witham; C. Knigge; B. T. Gänsicke; A. Aungwerojwit; R. L. M. Corradi; J. E. Drew; R. Greimel; P. J. Groot; L. Morales-Rueda; E. R. Rodriguez-Flores; P. Rodriguez-Gil; D. Steeghs

2006-01-01

161

Maximum Likelihood Estimation of Depth Maps Using Photometric Stereo  

E-print Network

Maximum Likelihood Estimation of Depth Maps Using Photometric Stereo Adam P. Harrison, Student Member, IEEE, and Dileepan Joseph, Member, IEEE Abstract--Photometric stereo and depth-map estimation provide a way to construct a depth map from images of an object under one viewpoint but with varying

Joseph, Dileepan

162

Monitoring Symbiotic Stars for Photometric Variability  

NASA Astrophysics Data System (ADS)

Seven new symbiotic star systems, discovered by spectroscopic follow-up of candidates from the IPHAS survey, have been photometrically observed for evidence of variability on the order of weeks to months. The IPHAS survey identified a number of symbiotic stars through analysis of their red colors and H-alpha emission, however, none of their other properties or behaviors were studied. The seven targets were monitored during the summers of 2013 and 2014 at the University of Washington's Manastash Ridge Observatory, each along with a unique set of five comparison stars using the H-alpha and Sloan r' and i' filters. The data from 2013 demonstrated variation of several targets by a few tenths of a magnitude in the H-alpha filter and large variations of almost one magnitude in the Sloan r' and i' filters. The 2014 observing season is ongoing, and the results will be presented in the accompanying poster.

Doughty, Caitlin; Lutz, Julie H.

2015-01-01

163

A Model-Independent Photometric Redshift Estimator  

E-print Network

We derive a simple empirical photometric redshift estimator using a training set of galaxies with multiband photometry and measured redshifts in the Hubble Deep Field (HDF). This estimator is model-independent; it does not use spectral templates. The dispersion between the estimated redshifts and the spectroscopically measured ones is small; the dispersions range from $\\sigma_z\\simeq 0.03$ to 0.1 for $z\\la 2$ galaxies, and from $\\sigma_z\\simeq 0.14$ to 0.25 for $z\\ga 2$ galaxies. The predictions provided by our empirical redshift estimator agree well with recently measured galaxy redshifts. We illustrate how our empirical redshift estimator can be modified to include flat spectrum galaxies with $1.4\\la z \\la 2$.

Yun Wang; Neta Bahcall; Edwin L. Turner

1999-06-15

164

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

165

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

166

An Isothermal Titration Calorimetric Method to Determine the Kinetic Parameters of Enzyme Catalytic Reaction  

E-print Network

Chemistry of Stable and Unstable Species, Peking University, Beijing 100871, China Received June 20, 2001 of enzyme. The molar reaction heat was calculated from the titration peak area divided by substrate moles change the reaction curve, it can be used as a probe to dig out other useful information. In this paper

Luhua, Lai

167

Applications of Isothermal Titration Calorimetry in RNA Biochemistry and Andrew L. Feig  

E-print Network

incremental addition of one species (a titrant) into its bind- ing partner (titrate) while monitoring. The integration of each peak in the power versus time curve corresponds to the heat associated with each increment. With that in mind, I have specifically excluded a large body of excellent work in the area of protein

Feig, Andrew

168

DNA heats up: Energetics of genome ejection from phage revealed by isothermal titration calorimetry.  

E-print Network

1 DNA heats up: Energetics of genome ejection from phage revealed by isothermal titration-stranded DNA into bacteria upon receptor binding in an essentially spontaneous way. This downhill thermodynamic process from the intact virion toward the empty viral capsid plus released DNA is made possible

169

Single-experiment displacement assay for quantifying high-affinity binding by isothermal titration calorimetry.  

PubMed

Isothermal titration calorimetry (ITC) is the gold standard for dissecting the thermodynamics of a biomolecular binding process within a single experiment. However, reliable determination of the dissociation constant (KD) from a single titration is typically limited to the range 100?M>KD>1nM. Interactions characterized by a lower KD can be assessed indirectly by so-called competition or displacement assays, provided that a suitable competitive ligand is available whose KD falls within the directly accessible window. However, this protocol is limited by the fact that it necessitates at least two titrations to characterize one high-affinity inhibitor, resulting in considerable consumption of both sample material and time. Here, we introduce a fast and efficient ITC displacement assay that allows for the simultaneous characterization of both a high-affinity ligand and a moderate-affinity ligand competing for the same binding site on a receptor within a single experiment. The protocol is based on a titration of the high-affinity ligand into a solution containing the moderate-affinity ligand bound to the receptor present in excess. The resulting biphasic binding isotherm enables accurate and precise determination of KD values and binding enthalpies (?H) of both ligands. We discuss the theoretical background underlying the approach, demonstrate its practical application to metal ion chelation, explore its potential and limitations with the aid of simulations and statistical analyses, and elaborate on potential applications to protein-inhibitor interactions. PMID:25461813

Krainer, Georg; Keller, Sandro

2014-11-13

170

Binding of Bovine Serum Albumin to Heparin Determined by Turbidimetric Titration and Frontal Analysis  

E-print Network

Binding of Bovine Serum Albumin to Heparin Determined by Turbidimetric Titration and Frontal albu- min (SA) and heparin (Hp). These two species form soluble complexes, the interaction increasing@chem.iupui.edu. 3 Abbreviations used: PGs, proteoglycans; HSPGs, heparin sulfate proteoglycans; GBM, glomerular

Dubin, Paul D.

171

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

172

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

173

On the establishment of adsorption equilibrium in n-butylamine titrations of the surface acidity  

Microsoft Academic Search

Using benzeneazodiphenylamine and Dimethyl Yellow as indicators, the difficulties associated with the establishment of an adsorption equlibrium between n-butylamine, the indicator and the acid centers of the catalyst in their titration by the Benesi method are demonstrated. The concentration of the amine affects the experimental values of surface acidity.

M. Baliková

1975-01-01

174

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

175

Bayesian inference from photometric redshift surveys  

NASA Astrophysics Data System (ADS)

We show how to enhance the redshift accuracy of surveys consisting of tracers with highly uncertain positions along the line of sight. This increased redshift precision is achieved by imposing an isotropy and two-point correlation prior in a Bayesian analysis and is independent of the process that estimates the photometric redshift. In particular, our method can deal with arbitrary forms of redshift uncertainties for each galaxy. As a byproduct, the method also infers the three-dimensional density field, essentially super-resolving high-density regions in redshift space. Our method fully takes into account the survey mask and selection function. It uses a simplified Poissonian picture of galaxy formation, relating preferred locations of galaxies to regions of higher density in the matter field. The method quantifies the remaining uncertainties in the three-dimensional density field and the true radial locations of galaxies by generating samples that are constrained by the survey data. The exploration of this high-dimensional, non-Gaussian joint posterior is made feasible using multiple-block Metropolis-Hastings sampling. We demonstrate the performance of our implementation on a simulation containing 2 × 107 galaxies. We further demonstrate the robustness of our method to prior misspecification by application to mock observations built from a large-scale structure simulation. In this test, initial Gaussian redshift uncertainties with ?z ˜ 0.03 can yield final redshift uncertainties of ?zf ˜ 0.003 in high-density regions. These results bear out the promise of Bayesian analysis for upcoming photometric large-scale structure surveys with tens of millions of galaxies.

Jasche, Jens; Wandelt, Benjamin D.

2012-09-01

176

Novel Methods for Predicting Photometric Redshifts from Broad Band Photometry using Virtual Sensors  

E-print Network

We calculate photometric redshifts from the Sloan Digital Sky Survey Main Galaxy Sample, The Galaxy Evolution Explorer All Sky Survey, and The Two Micron All Sky Survey using two new training-set methods. We utilize the broad-band photometry from the three surveys alongside Sloan Digital Sky Survey measures of photometric quality and galaxy morphology. Our first training-set method draws from the theory of ensemble learning while the second employs Gaussian process regression both of which allow for the estimation of redshift along with a measure of uncertainty in the estimation. The Gaussian process models the data very effectively with small training samples of approximately 1000 points or less. These two methods are compared to a well known Artificial Neural Network training-set method and to simple linear and quadratic regression. Our results show that robust photometric redshift errors as low as 0.02 RMS can regularly be obtained. We also demonstrate the need to provide confidence bands on the error estimation made by both classes of models. Our results indicate that variations due to the optimization procedure used for almost all neural networks, combined with the variations due to the data sample, can produce models with variations in accuracy that span an order of magnitude. A key contribution of this paper is to quantify the variability in the quality of results as a function of model and training sample. We show how simply choosing the "best" model given a data set and model class can produce misleading results.

M. J. Way; A. N. Srivastava

2006-07-06

177

An imaging-based photometric and colorimetric measurement method for characterizing OLED panels for lighting applications  

NASA Astrophysics Data System (ADS)

The organic light-emitting diode (OLED) has demonstrated its novelty in displays and certain lighting applications. Similar to white light-emitting diode (LED) technology, it also holds the promise of saving energy. Even though the luminous efficacy values of OLED products have been steadily growing, their longevity is still not well understood. Furthermore, currently there is no industry standard for photometric and colorimetric testing, short and long term, of OLEDs. Each OLED manufacturer tests its OLED panels under different electrical and thermal conditions using different measurement methods. In this study, an imaging-based photometric and colorimetric measurement method for OLED panels was investigated. Unlike an LED that can be considered as a point source, the OLED is a large form area source. Therefore, for an area source to satisfy lighting application needs, it is important that it maintains uniform light level and color properties across the emitting surface of the panel over a long period. This study intended to develop a measurement procedure that can be used to test long-term photometric and colorimetric properties of OLED panels. The objective was to better understand how test parameters such as drive current or luminance and temperature affect the degradation rate. In addition, this study investigated whether data interpolation could allow for determination of degradation and lifetime, L70, at application conditions based on the degradation rates measured at different operating conditions.

Zhu, Yiting; Narendran, Nadarajah; Tan, Jianchuan; Mou, Xi

2014-09-01

178

Acid-base titrations for polyacids: Significance of the pK sub a and parameters in the Kern equation  

NASA Technical Reports Server (NTRS)

A new method is suggested for calculating the dissociation constants of polyvalent acids, especially polymeric acids. In qualitative form the most significant characteristics of the titration curves are demonstrated and identified which are obtained when titrating the solutions of such acids with a standard base potentiometrically.

Meites, L.

1978-01-01

179

Determination of water samples and ene-diols or thiols in samples inaccessible for direct K.Fischer titration.  

PubMed

Novel reagents and the rapid technique were developed for the simultaneous determination of water and ene-diols or thiols in chemical products, drugs and other materials which are inaccessible for direct K.Fischer titration. The reagents consist of iodine, tetramethylammonium iodide or potassium iodide, base (diethanolamine, triethanolamine, sodium acetate and/or urea) in methanol mixed with N,N-dimethylformamide, or with formamide, or with dimethyl sulfoxide and N,N-dimethylformamide mixture as a solvent. The use of the reagents is based on the consecutive titration first of an ene-diol or thiol by the novel reagents and then of water by a conventional K.Fischer reagent in the same cell in a titration system protected from water vapour and oxygen, with a double burette and electrometric location of the end point in both titrations. The time for both titrations is 8-15 min. PMID:18966577

Sherman, F; Kuselman, I; Shenhar, A

1996-07-01

180

The Properties of Cataclysmic Variables In Photometric Halpha Surveys  

E-print Network

We report on the properties of 71 known cataclysmic variables (CVs) in photometric Halpha emission line surveys. Our study is motivated by the fact that the Isaac Newton Telescope (INT) Photometric Halpha Survey of the northern galactic plane (IPHAS) will soon provide r', i' and narrow-band Halpha measurements down to r' \\simeq 20 for all northern objects between -5 degrees orbital period; (v) short-period dwarf novae tend to have the strongest Halpha lines. These results imply that photometric emission line searches provide an efficient way of constructing CV samples that are not biased against detection of intrinsically faint, short-period systems.

A. R. Witham; C. Knigge; B. T. Gaensicke; A. Aungwerojwit; R. L. M. Corradi; J. E. Drew; R. Greimel; P. J. Groot; L. Morales-Rueda; E. R. Rodriguez-Flores; P. Rodriguez-Gil; D. Steeghs

2006-05-11

181

Voyager photometry of Triton - Haze and surface photometric properties  

NASA Technical Reports Server (NTRS)

The Voyager whole-disk observations of Triton at 0.41, 0.48, and 0.56 micron filter wavelengths are analyzed using a model which combines an improved version of Hapke's photometric equation with a thin atmospheric haze layer in the appropriate spherical geometry. The model is shown to describe accurately the phase curves over a range of phase angles and to agree with disk-resolved brightness scans along the photometric equator and mirror meridian. According to the model, the photometric parameters of Triton's regolith are reasonably typical of icy satellites, except for the extremely high (close to unity) single-scattering albedo.

Hillier, J.; Helfenstein, P.; Verbiscer, A.; Veverka, J.

1991-01-01

182

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

183

THE LAS CAMPANAS INFRARED SURVEY. III. THE H-BAND IMAGING SURVEY AND THE NEAR-INFRARED AND OPTICAL PHOTOMETRIC CATALOGS  

E-print Network

THE LAS CAMPANAS INFRARED SURVEY. III. THE H-BAND IMAGING SURVEY AND THE NEAR-INFRARED AND OPTICAL on broadband optical and near-infrared photometry, is designed to robustly identify a statistically significant-reduction techniques, and object identification procedures. We present sam- ple near-infrared and optical photometric

Goddard III, William A.

184

Improving Photometric Redshift Accuracy and Computational Efficiency  

NASA Astrophysics Data System (ADS)

Deriving high-quality photometric redshifts is necessary for extracting physical information from large-scale extragalactic surveys, but is computationally difficult. Although current grid-based template-fitting provide a sufficient level of accuracy for most purposes, they spend the majority of time for any given object (>99%) sampling regions of extremely low probability, are inefficient at exploring the relevant high-dimensional parameter space at fine resolution, and encourage a fundamental 'discretizing' of the space. We present preliminary results from a new MCMC-based algorithm that is able to use information on the entirety of parameter space and is designed to perform well even in extremely 'bumpy' spaces, yet at the same time is ~50 times more efficient than traditional grid-based approaches and easily parallelizable. We also explore machine learning-driven improvements to both the decision-making process as well as improvements in the input models that might allow substantial improvements in our determination of star formation histories and extinction curves for high-redshift galaxies.

Speagle, Josh S.; Capak, Peter L.; Masters, Daniel; Steinhardt, Charles L.

2015-01-01

185

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

186

Photometric determination of traces of metals  

SciTech Connect

The first three editions of this widely used classic were published under the title Colorimetric Determination of Traces of Metals, with E.B. Sandell as author. Part I (General Aspects) of the fourth edition was co-authored by E.B. Sandell and H. Onishi and published in 1978. After Sandell's death in 1984, Onishi assumed the monumental task of revising Part II. This book (Part IIA) consists of 21 chapters in which the photometric determinations of the individual metals, aluminium to lithium (including the lanthanoids), are described. Each chapter is divided into three sections: Separations, Methods of Determination, and Applications. The sections on Separations are of general interest and include methods based on precipitation, ion-exchange, chromatography, and liquid-liquid extraction. Molecular absorption and fluorescence techniques are described in the sections on determinations, and the emphasis is on the use of well-established reagents. Several reagents that have been recently introduced for the determination of trace levels of metals are also critically reviewed at the end of each section on methods of determination. Important applications of these methods to the determination of trace metals in complex organic and inorganic materials are described in detail at the end of each chapter.

Onishi, H.

1986-01-01

187

Photometric Properties of LBGs at z˜ 1  

NASA Astrophysics Data System (ADS)

After carefully cross-identifying the LBG candidates selected by FUV-NUV >2 from GALAX one-to-one with their optical counterparts and considering their re-estimated photometric redshifts, we redefine a new updated sample of 379 LBGs at 0.7 ˜< z ˜< 1.4. It is found that most of the LBGs are classified as starburst types with about 1/4 of them as irregular types and very few as Sbc and Scd types. They locate in the star forming sequence in the plane of star formation rate and stellar mass, rather than the main sequence as expected. The star formation rates (SFRs) and the stellar masses (M*) of the LBGs are from 4my to 220my and from 2.2× 108 msun to 7.7×1011 msun with their median values of ˜ 25my and ˜ 1010 msun, respectively. A “downsizing” effect is clearly found for the LBGs and it is more significant from later to earlier spectral type LBGs. The LBGs distribute in the “blue” cloud in the color-stellar mass diagram, and they are on average redder for earlier types. We suggest that star forming galaxies, at least the LBGs in our sample, evolve along the blue “cloud” from later to earlier types.

Chen, Z.; Shu, C. G.; Burgarella, D.; Buat, V.; Huang, J.-S.; Luo, Z. J.

2011-10-01

188

Photometric Decomposition of Mergers in Disk Galaxies  

NASA Astrophysics Data System (ADS)

Several observational studies and numerical simulations suggest that mergers must contribute to the evolution of galaxies; however, the role that they play is not yet fully understood. In this paper we study a sample of 52 double nucleus disk galaxies that are considered as candidates for a minor merger event. The luminosity of each of the nuclei and their relative separation are derived from a multi-component photometric fit of the galaxies in the Sloan Digital Sky Survey optical images. We find that the nuclei in most of the sources have projected separations <=4 kpc. The ratio of nuclear luminosities indicates that most of the systems are likely in the coalescence stage of a major merger. This is supported by the existence of a single galaxy disk in 65% of the systems studied and the finding of a correlation between nuclear luminosity and host luminosity for the single-disk systems: those sources fitted with as single disk are in a more evolved stage of the merger and present an enhancement of the nuclear luminosity compared to the double-disk systems, as expected from simulations of galaxy mergers. Finally, we identify a sample of 19 double nucleus disk galaxies in which the two nuclei are physically separated by <=1 kpc and constitute thus a sample of sub-kpc binary active galactic nucleus candidates.

Mezcua, M.; Lobanov, A. P.; Mediavilla, E.; Karouzos, M.

2014-03-01

189

BROADBAND PHOTOMETRIC REVERBERATION MAPPING OF NGC 4395  

SciTech Connect

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{sub 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{beta} and H{alpha}, 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{sub BH}. We measure the time lag for H{alpha} 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{sub BH} = (4.9 {+-} 2.6) Multiplication-Sign 10{sup 4} M{sub Sun }.

Edri, Haim; Rafter, Stephen E.; Kaspi, Shai; Behar, Ehud [Physics Department, the Technion, Haifa 32000 (Israel); Chelouche, Doron, E-mail: rafter@physics.technion.ac.il, E-mail: shai@physics.technion.ac.il, E-mail: behar@physics.technion.ac.il, E-mail: doron@sci.haifa.ac.il [Physics Department, Faculty of Natural Sciences, University of Haifa, Haifa (Israel)

2012-09-01

190

Indirect determination of fluoride by EDTA back-titration of lanthanum.  

PubMed

Semimicro to macro amounts of fluoride ion (0.4-100 mg) are determined rapidly and accurately by precipitation with an excess of lanthanum at pH 2.5-2.8 by digestion on a water-bath, cooling to room temperature, addition of excess of EDTA and back-titration of the excess with zinc solution to the Xylenol Orange end-point at ph 5.8-5..9. Large amounts of chloride, acetate and perchlorate, and small amounts of sulphate and silicate do not interfere, but phosphate does. This method is much superior to the usual thorium nitrate titration method and can be applied after preliminary separation of fluorine by steam distillation or pyrolysis. PMID:18962019

Murase, K; Nakagawa, G; Kodama, K; Shiraishi, N

1977-01-01

191

Successful management of a difficult cancer pain patient by appropriate adjuvant and morphine titration.  

PubMed

Morphine has been used for many years to relieve cancer pain. Oral morphine (in either immediate release or modified release form) remains the analgesic of choice for moderate or severe cancer pain. The dose of oral morphine is titrated up to achieve adequate relief from pain with minimal side effects. Antidepressant and anticonvulsant drugs, when used in addition to conventional analgesics, give excellent relief from cancer pain. Most cancer pain responds to pharmacological measures with oral morphine but some pain like neuropathic and bony pain, pain in children and elderly age group, and advanced malignancy pain are very difficult to treat. Here, we report the management of a similar patient of severe cancer pain and the difficulty that we came across during dose titration of oral morphine and adjuvant analgesic. PMID:21976860

Rana, Shiv Ps; Ahmed, Arif; Kumar, Vindo; Chaudhary, Prakash K; Khurana, Deepa; Mishra, Seema

2011-05-01

192

Successful Management of a Difficult Cancer Pain Patient by Appropriate Adjuvant and Morphine Titration  

PubMed Central

Morphine has been used for many years to relieve cancer pain. Oral morphine (in either immediate release or modified release form) remains the analgesic of choice for moderate or severe cancer pain. The dose of oral morphine is titrated up to achieve adequate relief from pain with minimal side effects. Antidepressant and anticonvulsant drugs, when used in addition to conventional analgesics, give excellent relief from cancer pain. Most cancer pain responds to pharmacological measures with oral morphine but some pain like neuropathic and bony pain, pain in children and elderly age group, and advanced malignancy pain are very difficult to treat. Here, we report the management of a similar patient of severe cancer pain and the difficulty that we came across during dose titration of oral morphine and adjuvant analgesic. PMID:21976860

Rana, Shiv PS; Ahmed, Arif; Kumar, Vindo; Chaudhary, Prakash K; Khurana, Deepa; Mishra, Seema

2011-01-01

193

Implementation of a titrated oxygen protocol in the out-of-hospital setting.  

PubMed

Oxygen is one of the most frequently-used therapeutic agents in medicine and the most commonly administered drug by prehospital personnel. There is increasing evidence of harm with too much supplemental oxygen in certain conditions, including stroke, chronic obstructive pulmonary disease (COPD), neonatal resuscitations, and in postresuscitation care. Recent guidelines published by the British Thoracic Society (BTS) advocate titrated oxygen therapy, but these guidelines have not been widely adapted in the out-of-hospital setting where high-flow oxygen is the standard. This report is a description of the implementation of a titrated oxygen protocol in a large urban-suburban Emergency Medical Services (EMS) system and a discussion of the practical application of this out-of-hospital protocol. PMID:24983332

Bosson, Nichole; Gausche-Hill, Marianne; Koenig, William

2014-08-01

194

Determination of the catalytic activity of binuclear metallohydrolases using isothermal titration calorimetry.  

PubMed

Binuclear metallohydrolases are a large and diverse family of enzymes that are involved in numerous metabolic functions. An increasing number of members find applications as drug targets or in processes such as bioremediation. It is thus essential to have an assay available that allows the rapid and reliable determination of relevant catalytic parameters (k cat, K m, and k cat/K m). Continuous spectroscopic assays are frequently only possible by using synthetic (i.e., nonbiological) substrates that possess a suitable chromophoric marker (e.g., nitrophenol). Isothermal titration calorimetry, in contrast, affords a rapid assay independent of the chromophoric properties of the substrate-the heat associated with the hydrolytic reaction can be directly related to catalytic properties. Here, we demonstrate the efficiency of the method on several selected examples of this family of enzymes and show that, in general, the catalytic parameters obtained by isothermal titration calorimetry are in good agreement with those obtained from spectroscopic assays. PMID:24414447

Pedroso, Marcelo M; Ely, Fernanda; Lonhienne, Thierry; Gahan, Lawrence R; Ollis, David L; Guddat, Luke W; Schenk, Gerhard

2014-03-01

195

Photometric and magnetic variability of the Ap star GY And  

NASA Astrophysics Data System (ADS)

We present the results of photometric and magnetic monitoring of a well-known long-period Ap star GY And. This research was inspired by the unusual "secular" variability of the B - V color index. Photometric monitoring was carried out with the 60-cm reflector of the Crimean Laboratory of the Moscow State University, where 420 brightness estimates were obtained during 2011-2014 with the Johnson system broadband U, B, and V filters. Magnetic monitoring was carried out at the 1-m telescope of the Special Astrophysical Observatory. The duration of photometric observations is about 54 years, and the duration of magnetic monitoring is 64 years. As a result, we have refined the period and the parameters of variability of the magnetic field, and the photometric behavior. We demonstrate that the peculiar "secular" color variability is explained by the off-duty factor of the observations.

Metlova, N. V.; Bychkov, V. D.; Bychkova, L. V.; Madej, J.

2014-07-01

196

Coulometric Karl Fischer titration of trace water in diaphragm-free cells  

Microsoft Academic Search

Factors influencing the accuracy and precision for diaphragm-free Karl Fischer coulometric determinations of low ?g-amounts of water have been studied using the Metrohm 756 (pulsed current) coulometer and eight different types of commercial coulometric reagents and some modifications of these. As in the case of diaphragm-free coulometric titration of large amounts of water, the positive errors, due to the formation

William Larsson; Anders Cedergren

2005-01-01

197

Thermodynamics of IonInduced RNA Folding in the Hammerhead Ribozyme: An Isothermal Titration Calorimetric Study †  

Microsoft Academic Search

The hammerhead ribozyme undergoes a well-defined two-stage conformational folding process, induced by the binding of magnesium ions. In this study, we have used isothermal titration calorimetry to analyze the thermodynamics of magnesium binding and magnesium ion-induced folding of the ribozyme. Binding to the natural sequence ribozyme is strongly exothermic and can be analyzed in terms of sequential interaction at two

Christian Hammann; Alan Cooper; David M. J. Lilley

2001-01-01

198

Kinetic titration with differential thermometric determination of the end-point.  

PubMed

A method has been described for the determination of concentrations below 10(-4)M by applying catalytic reactions and using thermometric end-point determination. A reference solution, identical with the sample solution except for catalyst, is titrated with catalyst solution until the rates of reaction become the same, as shown by a null deflection on a galvanometer connected via bridge circuits to two opposed thermistors placed in the solutions. PMID:18960338

Sajó, I

1968-06-01

199

31P NMR and isothermal titration calorimetry studies on polyoxomolybdates-catalyzed hydrolysis of ATP  

Microsoft Academic Search

ATP hydrolysis in the presence of polyoxomolybdates at pH levels of 6, 4, and 2 has been investigated with a help of high pressure liquid chromatography (HPLC) analyses, 31P- and 1H NMR measurements, and isothermal titration calorimetry (ITC). The polyoxomolybdates-induced ATP-hydrolysis proceeded satisfactorily in pH<6 media at 20°C with an optimum pH level of 4, while it was significantly depressed

Eri Ishikawa; Toshihiro Yamase

2006-01-01

200

A Geochemical Reaction Model for Titration of Contaminated Soil and Groundwater at the Oak Ridge Reservation  

NASA Astrophysics Data System (ADS)

This study investigates geochemical reactions during titration of contaminated soil and groundwater at the Oak Ridge Reservation in eastern Tennessee. The soils and groundwater exhibits low pH and high concentrations of aluminum, calcium, magnesium, manganese, various trace metals such as nickel and cobalt, and radionuclides such as uranium and technetium. The mobility of many of the contaminant species diminishes with increasing pH. However, base additions to increase pH are strongly buffered by various precipitation/dissolution and adsorption/desorption reactions. The ability to predict acid-base behavior and associated geochemical effects is thus critical to evaluate remediation performance of pH manipulation strategies. This study was undertaken to develop a practical but generally applicable geochemical model to predict aqueous and solid-phase speciation during soil and groundwater titration. To model titration in the presence of aquifer solids, an approach proposed by Spalding and Spalding (2001) was utilized, which treats aquifer solids as a polyprotic acid. Previous studies have shown that Fe and Al-oxyhydroxides strongly sorb dissolved Ni, U and Tc species. In this study, since the total Fe concentration is much smaller than that of Al, only ion exchange reactions associated with Al hydroxides are considered. An equilibrium reaction model that includes aqueous complexation, precipitation, ion exchange, and soil buffering reactions was developed and implemented in the code HydroGeoChem 5.0 (HGC5). Comparison of model results with experimental titration curves for contaminated groundwater alone and for soil- water systems indicated close agreement. This study is expected to facilitate field-scale modeling of geochemical processes under conditions with highly variable pH to develop practical methods to control contaminant mobility at geochemically complex sites.

Zhang, F.; Parker, J. C.; Gu, B.; Luo, W.; Brooks, S. C.; Spalding, B. P.; Jardine, P. M.; Watson, D. B.

2007-12-01

201

Acid-base titrations using microfluidic paper-based analytical devices.  

PubMed

Rapid and simple acid-base titration was accomplished using a novel microfluidic paper-based analytical device (?PAD). The ?PAD was fabricated by wax printing and consisted of ten reservoirs for reaction and detection. The reaction reservoirs contained various amounts of a primary standard substance, potassium hydrogen phthalate (KHPth), whereas a constant amount of phenolphthalein was added to all the detection reservoirs. A sample solution containing NaOH was dropped onto the center of the ?PAD and was allowed to spread to the reaction reservoirs where the KHPth neutralized it. When the amount of NaOH exceeded that of the KHPth in the reaction reservoirs, unneutralized hydroxide ion penetrated the detection reservoirs, resulting in a color reaction from the phenolphthalein. Therefore, the number of the detection reservoirs with no color change determined the concentration of the NaOH in the sample solution. The titration was completed within 1 min by visually determining the end point, which required neither instrumentation nor software. The volumes of the KHPth and phenolphthalein solutions added to the corresponding reservoirs were optimized to obtain reproducible and accurate results for the concentration of NaOH. The ?PADs determined the concentration of NaOH at orders of magnitude ranging from 0.01 to 1 M. An acid sample, HCl, was also determined using Na2CO3 as a primary standard substance instead of KHPth. Furthermore, the ?PAD was applicable to the titrations of nitric acid, sulfuric acid, acetic acid, and ammonia solutions. The ?PADs were stable for more than 1 month when stored in darkness at room temperature, although this was reduced to only 5 days under daylight conditions. The analysis of acidic hot spring water was also demonstrated in the field using the ?PAD, and the results agreed well with those obtained by classic acid-base titration. PMID:25423320

Karita, Shingo; Kaneta, Takashi

2014-12-16

202

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

203

Photometric study of an eclipsing binary in Praesepe  

NASA Astrophysics Data System (ADS)

We present CCD photometric observations of an eclipsing binary in the direction of the open cluster Praesepe using the 2 m telescope at IUCAA Girawali Observatory, India. Though the system was classified as an eclipsing binary by Pepper et al., detailed investigations have been lacking. The photometric solutions using the Wilson-Devinney code suggest that it is a W-type W UMa system and, interestingly, the system parameters are similar to another contact binary system SW Lac.

Shanti Priya, Devarapalli; Sriram, Kandulapati; Vivekananda Rao, Pasagada

2013-04-01

204

Photometric monitoring of 2060 Chiron's brightness at perihelion  

Microsoft Academic Search

The results of photometric and spectroscopic observations of comet\\/asteroid 2060 Chiron carried on at the Observatório do Pico-dos-Dias (Brazil), at the European Southern Observatory (Chile) and at the Mauna Kea Observatory (Hawaii) during 1996 are presented. The analysis of the photometric data shows that even at a minimum of brightness 2060 Chiron presents some activity. The absolute magnitude, Hv, varied

D. Lazzaro; M. A. Florczak; C. A. Angeli; J. M. Carvano; A. S. Betzler; A. A. Casati; M. A. Barucci; A. Doressoundiram; M. Lazzarin

1997-01-01

205

EPR monitored redox titration of the cofactors of Saccharomyces cerevisiae Nar1.  

PubMed

Electron Paramagnetic Resonance (EPR) monitored redox titrations are a powerful method to determine the midpoint potential of cofactors in proteins and to identify and quantify the cofactors in their detectable redox state. The technique is complementary to direct electrochemistry (voltammetry) approaches, as it does not offer information on electron transfer rates, but does establish the identity and redox state of the cofactors in the protein under study. The technique is widely applicable to any protein containing an electron paramagnetic resonance (EPR) detectable cofactor. A typical titration requires 2 ml protein with a cofactor concentration in the range of 1-100 µM. The protein is titrated with a chemical reductant (sodium dithionite) or oxidant (potassium ferricyanide) in order to poise the sample at a certain potential. A platinum wire and a Ag/AgCl reference electrode are connected to a voltmeter to measure the potential of the protein solution A set of 13 different redox mediators is used to equilibrate between the redox cofactors of the protein and the electrodes. Samples are drawn at different potentials and the Electron Paramagnetic Resonance spectra, characteristic for the different redox cofactors in the protein, are measured. The plot of the signal intensity versus the sample potential is analyzed using the Nernst equation in order to determine the midpoint potential of the cofactor. PMID:25490157

Hagedoorn, Peter-Leon; van der Weel, Laura; Hagen, Wilfred R

2014-01-01

206

Chaotic dynamics of resting ventilatory flow in humans assessed through noise titration  

E-print Network

The mammalian ventilatory behavior exhibits nonlinear dynamics as reflected by certain nonlinearity or complexity indicators (e.g. correlation dimension, approximate entropy, Lyapunov exponents...) but this is not sufficient to determine its possible chaotic nature. To address this, we applied the noise titration technique, previously shown to discern and quantify chaos in short and noisy time series, to ventilatory flow recordings obtained in quietly breathing normal humans. Nine subjects (8 men and 1 woman, 24-42 yrs) were studied during 15-minute epochs of ventilatory steady-state (10.1 +/- 3.0 breaths/minute, tidal volume 0.63 +/- 0.2L). Noise titration applied to the unfiltered signals subsampled at 5 Hz detected nonlinearity in all cases (noise limit 20.2 +/- 12.5%). Noise limit values were weakly correlated to the correlation dimension and the largest Lyapunov exponent of the signals. This study shows that the noise titration approach evidences a chaotic dimension to the behavior of ventilatory flow over time in normal humans during tidal breathing.

Marc Wysocki; Marie-Noelle Fiamma; Christian Straus; Chi-Sang Poon; Thomas Similowski

2006-06-12

207

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

PubMed Central

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. PMID:24580252

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

2014-01-01

208

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

209

Determination of sulphuric acid in process effluent streams using sequential injection titration.  

PubMed

Sulphuric acid in process effluent streams from an electrorefining copper plant was analysed with a sequential injection (SI) titration system using sodium hydroxide as titrant. In the proposed SI titration system a base titrant, acid analyte and base titrant zone were injected sequentially into a distilled water carrier stream in a holding coil and swept by flow reversal through a reaction coil to the detector. The base zones contained bromothymol blue as indicator and the endpoint was monitored spectrophotometrically at 620 nm. The influence of carrier stream flow rate, acid and base zone volumes and titrant concentration on the linear range of the method was studied to obtain an optimum. A linear relationship between peak width and logarithm of the acid concentration was obtained in the range 0.006-0.178 mol l(-1) of H(2)SO(4) for a NaOH concentration of 0.002 mol l(-1). The results obtained for the SI titration of process samples were in good agreement with a standard potentiometric method with an RSD<0.75% and a sample frequency of 23 samples h(-1). PMID:18967965

du Plessis, H; van Staden, J F

2000-05-31

210

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.

211

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

212

Extraction preconcentration and photometric determination of chlorophenols and naphthols in aqueous media  

SciTech Connect

Mono- and bicyclic hydroxy compounds (phenol, chlorophenols, naphthols, and naphtholsulfonic acids) are industrial toxicants; these compounds occur in waste water from the production of dyestuffs, polymer materials, perfumes, drugs, varnishes, paints, and pesticides. Phenol, chlorophenols, and naphthols are carcinogenic toxicants; they may constitute a threat to living organisms in reservoirs and biologically active silts. The presence of these compounds changes the oxygen balance of water basins. The maximum permissible concentration of these compounds in water varies from 10{sup {minus}1} (naphthols) to 10{sup {minus}4} mg/L (chlorophenols). For the reliable determination of microquantities of toxicants in water, we proposed procedures that include extraction by lower alcohols, organic acids, and hexane or hexane-hexanol solutions of solvotropic reagents (dialkyl phthalates and trialkyl phthalates). A set of extraction photometric procedures has been developed for the total and selective determination of microquantities of phenol and naphthol toxicants in aqueous media.

Korenman, Ya.I.; Kalinkina, S.P.; Sukhanov, P.T. [Voronezh Inst. of Technology (Russian Federation)] [and others

1994-11-01

213

The Strömvil Photometric System: Classifying Faint Stars  

NASA Astrophysics Data System (ADS)

Since 1996 a group of astronomers has been working on setting up and then using the Strömvil photometric system, a combination of the four Strömgren and three Vilnius system filters. The system was announced in Straižys et al. (1996). A summary of the work up to 2003 can be found in S?džius et al. (2003). The major ability of the Strömvil system is that, from photoelectric measures alone one can determine the reddening, temperature, gravity and metalicity of stars. With all the new surveys that have been made and ones yet to be made, such a system will be of great use to identify the nature of the new faint stars that will be identified and classify them by stellar type. And since the reddening can be calculated for each region, the intrinsic properties of these stars can be determined. The main observational programs underway in the Strömvil system at present are: 1. Setting up the primary standards. Kazlauskas et al. (2005) have published a list of 780 photoelectric standards in the northern hemisphere. 2. At the Vatican Advanced Technology Telescope on Mt. Graham Boyle and Philip have been making CCD Strömvil measures of open and globular clusters. Observations are taken in each run of the rich open cluster M 67. These measures are matched to the high-accuracy CCD photometry of Laugalys et al. (2004) by constraining the corrections to each flatfield to provide the needed one percent photometry in new program fields with only a few standards for zero-point calibration. 3. At Casleo, in Argentina, Philip and Pintado have been observing clusters with the 2.15 meter telescope. 4. On the data reduction side Janusz and Boyle have written the CommandLog which automates the process of data reduction for members of our group. This will ensure that all observations will be reduced in exactly the same way.

Philip, A. G. D.; Boyle, R. P.

2006-08-01

214

Determination of free acidic and alkaline residues of protein via moving reaction boundary titration in microdevice electrophoresis.  

PubMed

As two important physico-chemical parameters, the acidic and alkaline residues of protein are of evident significance for the evaluation of protein properties and the design of relevant separation and analysis. However, there is still no electrophoretic method used for the direct detection of free acidic and alkaline residues of protein. Herein, we developed the concepts of moving reaction boundary (MRB) and MRB titration, relevant MRB titration theory, and the method of microdevice electrophoresis for the determination of free acidic and alkaline residues of protein. In the MRB titration, the boundary was created with acid or alkali and target protein immobilized via highly cross-linked polyacrylamide gel (PAG). It was theoretically revealed that the number of free acidic or alkaline residues of protein was as a function of MRB displacement in the electrophoretic titration system. As a proof of concept, seven model proteins were chosen for the determination of acidic or alkaline residues of protein via MRB titration. The results showed that the numbers of free acidic and alkaline residues of proteins detected were in good agreement with those obtained from the relevant amino sequences in the NCBI database, demonstrating the feasibility of the developed concept, theory and technique. The general methodology of MRB titration has potential application for inexpensive, facilitative and informative protein structure analysis of free acidic or alkaline residues of protein. PMID:23671907

Wang, Hou-yu; Li, Si; Tang, Yun-yun; Dong, Jing-yu; Fan, Liu-yin; Cao, Cheng-xi

2013-06-21

215

Photometric Studies of GEO Orbital 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 Cerro Tololo Inter- American Observatory (CTIO) 0.9-m for orbits and photometry. Our goal is to determine 6 parameter orbits and measure colors for all objects fainter than R=15th 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? More than 90 calibrated sequences of R-B-V-I-R magnitudes for a sample of 50 objects 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. We will compare our observations with models and laboratory measurements of selected surfaces.

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

2009-01-01

216

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

217

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

218

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

219

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

220

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

221

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

222

[Model UF-2 mutant of Staphylococcus aureus 209 P for titrating Vibrio cholera enterotoxin].  

PubMed

The identical character of the action of crude V. cholerae enterotoxin on the anaerobic dehydrogenases of the UV-2 mutant of S. aureus 209 p and the surviving culture of Ehrlich's carcinoma has been revealed. The range of this action is linked with the concentration of the toxin and varies from the stimulation of cell dehydrogenases to their complete suppression. The rapid method for the titration of the enterotoxin in the dehydrogenase suppression test with the use of the bacterial model is proposed. PMID:6353817

Pasternak, N A; Ved'mina, E A; Andrusenko, I T; Shenderovich, V A; Zhuravleva, T P

1983-07-01

223

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

224

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

225

Automated high-pressure titration system with in situ infrared spectroscopic detection  

SciTech Connect

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 CO{sub 2} (scCO{sub 2}) to generate an infrared calibration curve and determine the solubility of water in CO{sub 2} at 50?°C and 90 bar. Next, we characterized the partitioning of water between a montmorillonite clay and scCO{sub 2} 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 scCO{sub 2} hydration, and ATR measurements provided insights into competitive residency of water and CO{sub 2} 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 (Mg{sub 2}SiO{sub 4}) in water-bearing scCO{sub 2} at 50?°C and 90 bar. Immediately after water dissolved in the scCO{sub 2}, 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 scCO{sub 2} and minerals relevant to underground storage of CO{sub 2} (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., E-mail: chris.thompson@pnnl.gov; Martin, Paul F.; Chen, Jeffrey; Schaef, Herbert T.; Rosso, Kevin M.; Felmy, Andrew R.; Loring, John S. [Pacific Northwest National Laboratory, Richland, Washington 99352 (United States)] [Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Benezeth, Pascale [Géosciences Environnement Toulouse (GET), CNRS-Université de Toulouse, 31400 Toulouse (France)] [Géosciences Environnement Toulouse (GET), CNRS-Université de Toulouse, 31400 Toulouse (France)

2014-04-15

226

Automated High-Pressure Titration System with In Situ Infrared Spectroscopic Detection  

SciTech Connect

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 radiation from a Fourier transform infrared spectrometer into the cell along transmission or ATR light paths. The versatility of the high-pressure IR titration system is 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 hours, 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.

2014-04-17

227

Spectral reflectance and photometric properties of selected rocks  

USGS Publications Warehouse

Studies of the spectral reflectance and photometric properties of selected rocks at the USGS Mill Creek, Oklahoma, remote sensing test site demonstrate that discrimination of rock types is possible through reflection measurements, but that the discrimination is complicated by surface conditions, such as weathering and lichen growth. Comparisons between fresh-broken, weathered, and lichen-covered granite show that whereas both degree of weathering and amount of lichen cover change the reflectance quality of the granite, lichen cover also considerably changes the photometric properties of the granite. Measurements of the spectral reflectance normal to the surface of both limestone and dolomite show limestone to be more reflective than dolomite in the wavelength range from 380 to 1550 nanometers. The reflectance difference decreases at view angles greater than 40?? owing to the difference in the photometric properties of dolomite and limestone. ?? 1971.

Watson, R.D.

1971-01-01

228

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

229

Photometric Calibration of Consumer Video Cameras  

NASA Technical Reports Server (NTRS)

Equipment and techniques have been developed to implement a method of photometric calibration of consumer video cameras for imaging of objects that are sufficiently narrow or sufficiently distant to be optically equivalent to point or line sources. Heretofore, it has been difficult to calibrate consumer video cameras, especially in cases of image saturation, because they exhibit nonlinear responses with dynamic ranges much smaller than those of scientific-grade video cameras. The present method not only takes this difficulty in stride but also makes it possible to extend effective dynamic ranges to several powers of ten beyond saturation levels. The method will likely be primarily useful in astronomical photometry. There are also potential commercial applications in medical and industrial imaging of point or line sources in the presence of saturation.This development was prompted by the need to measure brightnesses of debris in amateur video images of the breakup of the Space Shuttle Columbia. The purpose of these measurements is to use the brightness values to estimate relative masses of debris objects. In most of the images, the brightness of the main body of Columbia was found to exceed the dynamic ranges of the cameras. A similar problem arose a few years ago in the analysis of video images of Leonid meteors. The present method is a refined version of the calibration method developed to solve the Leonid calibration problem. In this method, one performs an endto- end calibration of the entire imaging system, including not only the imaging optics and imaging photodetector array but also analog tape recording and playback equipment (if used) and any frame grabber or other analog-to-digital converter (if used). To automatically incorporate the effects of nonlinearity and any other distortions into the calibration, the calibration images are processed in precisely the same manner as are the images of meteors, space-shuttle debris, or other objects that one seeks to analyze. The light source used to generate the calibration images is an artificial variable star comprising a Newtonian collimator illuminated by a light source modulated by a rotating variable neutral- density filter. This source acts as a point source, the brightness of which varies at a known rate. A video camera to be calibrated is aimed at this source. Fixed neutral-density filters are inserted in or removed from the light path as needed to make the video image of the source appear to fluctuate between dark and saturated bright. The resulting video-image data are analyzed by use of custom software that determines the integrated signal in each video frame and determines the system response curve (measured output signal versus input brightness). These determinations constitute the calibration, which is thereafter used in automatic, frame-by-frame processing of the data from the video images to be analyzed.

Suggs, Robert; Swift, Wesley, Jr.

2007-01-01

230

A single-beam titration method for the quantification of open-path Fourier transform infrared spectroscopy  

NASA Astrophysics Data System (ADS)

This study introduced a quantitative method that can be used to measure the concentration of analytes directly from a single-beam spectrum of open-path Fourier Transform Infrared Spectroscopy (OP-FTIR). The peak shapes of the analytes in a single-beam spectrum were gradually canceled (i.e., "titrated") by dividing an aliquot of a standard transmittance spectrum with a known concentration, and the sum of the squared differential synthetic spectrum was calculated as an indicator for the end point of this titration. The quantity of a standard transmittance spectrum that is needed to reach the end point can be used to calculate the concentrations of the analytes. A NIST traceable gas standard containing six known compounds was used to compare the quantitative accuracy of both this titration method and that of a classic least square (CLS) using a closed-cell FTIR spectrum. The continuous FTIR analysis of industrial exhausting stack showed that concentration trends were consistent between the CLS and titration methods. The titration method allowed the quantification to be performed without the need of a clean single-beam background spectrum, which was beneficial for the field measurement of OP-FTIR. Persistent constituents of the atmosphere, such as NH3, CH4 and CO, were successfully quantified using the single-beam titration method with OP-FTIR data that is normally inaccurate when using the CLS method due to the lack of a suitable background spectrum. Also, the synthetic spectrum at the titration end point contained virtually no peaks of analytes, but it did contain the remaining information needed to provide an alternative means of obtaining an ideal single-beam background for OP-FTIR.

Sung, Lung-Yu; Lu, Chia-Jung

2014-09-01

231

A photometric study of the counterglow from space.  

NASA Technical Reports Server (NTRS)

Photometric observations of the region of the counterglow (Gegenschein) made from OSO-6 are examined. The observations were made during the September to October 1970 period when the counterglow was between the Milky Way arms at a relatively high (negative) galactic latitude. The lines of sight included a slice across the antisun region at an inclination of 48 degrees to the ecliptic. A comparison is made between the photometric gradients as measured from the spacecraft and similar gradients deduced from ground-based observations.

Roach, F. E.; Carroll, B.; Aller, L. H.; Roach, J. R.

1973-01-01

232

CosmoPhotoz: Photometric redshift estimation using generalized linear models  

NASA Astrophysics Data System (ADS)

CosmoPhotoz determines photometric redshifts from galaxies utilizing their magnitudes. The method uses generalized linear models which reproduce the physical aspects of the output distribution. The code can adopt gamma or inverse gaussian families, either from a frequentist or a Bayesian perspective. A set of publicly available libraries and a web application are available. This software allows users to apply a set of GLMs to their own photometric catalogs and generates publication quality plots with no involvement from the user. The code additionally provides a Shiny application providing a simple user interface.

de Souza, Rafael S.; Elliott, Jonathan; Krone-Martins, Alberto; Ishida, Emille E. O.; Hilbe, Joseph; Cameron, Ewan

2014-08-01

233

Spectro-Photometric Constraints on Galaxy Evolution with NGST  

E-print Network

The Next Generation Space Telescope (NGST) will gather unprecedented spectro-photometric data on galaxies out to the highest redshifts. It is therefore crucial to identify the spectro-photometric diagnostics within reach of NGST, which will allow us to best constrain the history of star formation and evolution of galaxies. The primary parameters to be determined are the ongoing rate of star formation and stellar mass of galaxies at all redshifts. In this context, we briefly review the reliability of various star formation rate and mass estimators of galaxies in a full range of redshifts, with particular emphasis on the relative merits of optical versus near- to mid-IR observations.

S. Charlot

1998-10-26

234

Theoretical Isochrones in the Observational Plane of the Vilnius Photometric System  

NASA Astrophysics Data System (ADS)

Theoretical isochrones for the initial chemical composition [Z=0.0004, Y=0.23], [Z=0.004, Y=0.24], [Z=0.008, Y=0.25] and [Z=0.02, Y=0.28] and ages in the range 4* 10(6) yr to 16* 10(9) yr are presented in the observational plane of the Vilnius photometric system. The isochrones have been calculated from stellar models computed with the most recent radiative opacities by Iglesias et al. (1992) using the same procedure as described by Bertelli et al. (1994). All stellar models were followed from the zero age main sequence (ZAMS) to the central carbon ignition for massive stars or to the beginning of the thermally pulsing regime of the asymptotic giant branch phase (TP-AGB) for low and intermediate mass stars. For each isochrone, we give the current mass, effective temperatures, bolometric and visual magnitudes, U--P, P--X, X--Y, Y--Z, Z--V and V--S color indices of the Vilnius photometric system and the luminosity function for the case of the Salpeter law.

Bressan, A.; Tautvaisiene, G.

235

Simultaneous Estimation of Photometric Redshifts and SED Parameters: Improved Techniques and a Realistic Error Budget  

NASA Astrophysics Data System (ADS)

We present the results of recent work seeking to improve the accuracy of joint galaxy photometric redshift estimation and spectral energy distribution (SED) fitting. By simulating different sources of uncorrected systematic errors, we show that if the uncertainties on the photometric redshifts are estimated correctly, so are those on the other SED fitting parameters, such as stellar mass, stellar age, and dust reddening. Furthermore, we find that if the redshift uncertainties are over(under)-estimated, the uncertainties in SED parameters will be over(under)-estimated by similar amounts. These results hold even in the presence of severe systematics and provide, for the first time, a mechanism to validate the uncertainties on these parameters via comparison with spectroscopic redshifts. We show that template incompleteness, a major cause of inaccuracy in this process, is ``flagged" by a large fraction of outliers in redshift and that it can be corrected by using more flexible stellar population models. We propose a new technique (annealing) to re-calibrate the joint uncertainties in the photo-z and SED fitting parameters without compromising the performance of the SED fitting + photo-z estimation. This procedure provides a consistent estimation of the multidimensional probability distribution function in SED fitting + z parameter space, including all correlations.

Acquaviva, Viviana; Raichoor, Anand; Gawiser, Eric J.

2015-01-01

236

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

237

SHARDS: AN OPTICAL SPECTRO-PHOTOMETRIC SURVEY OF DISTANT GALAXIES  

SciTech Connect

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 arcmin{sup 2} at wavelengths between 500 and 950 nm with 24 contiguous medium-band filters (providing a spectral resolution R {approx} 50). The data reach an AB magnitude of 26.5 (at least at a 3{sigma} 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 {approx}< 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 {tau} = 100-200 Myr, age around 1.5-2.0 Gyr, solar or slightly sub-solar metallicity, and moderate extinction, A(V) {approx} 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.

Perez-Gonzalez, Pablo G.; Cava, Antonio; Barro, Guillermo; Villar, Victor; Cardiel, Nicolas; Espino, Nestor; Gallego, Jesus [Departamento de Astrofisica, Facultad de CC. Fisicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain)] [Departamento de Astrofisica, Facultad de CC. Fisicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain); Ferreras, Ignacio [Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT (United Kingdom)] [Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT (United Kingdom); Rodriguez-Espinosa, Jose Miguel; Balcells, Marc; Cepa, Jordi [Instituto de Astrofisica de Canarias, E-38200 La Laguna, Tenerife (Spain)] [Instituto de Astrofisica de Canarias, E-38200 La Laguna, Tenerife (Spain); Alonso-Herrero, Almudena [Instituto de Fisica de Cantabria, CSIC-Universidad de Cantabria, E-39005 Santander (Spain)] [Instituto de Fisica de Cantabria, CSIC-Universidad de Cantabria, E-39005 Santander (Spain); Cenarro, Javier [Centro de Estudios de Fisica del Cosmos de Aragon, Plaza San Juan 1, Planta 2, E-44001 Teruel (Spain)] [Centro de Estudios de Fisica del Cosmos de Aragon, Plaza San Juan 1, Planta 2, E-44001 Teruel (Spain); Charlot, Stephane [Institut d'Astrophysique de Paris, CNRS, Universite Pierre and Marie Curie, UMR 7095, 98bis bd Arago, F-75014 Paris (France)] [Institut d'Astrophysique de Paris, CNRS, Universite Pierre and Marie Curie, UMR 7095, 98bis bd Arago, F-75014 Paris (France); Cimatti, Andrea [Dipartimento di Astronomia, Universita degli Studi di Bologna, I-40127 Bologna (Italy)] [Dipartimento di Astronomia, Universita degli Studi di Bologna, I-40127 Bologna (Italy); Conselice, Christopher J. [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom)] [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Daddi, Emmanuele; Elbaz, David [CEA, Laboratoire AIM, Irfu/SAp, F-91191 Gif-sur-Yvette (France)] [CEA, Laboratoire AIM, Irfu/SAp, F-91191 Gif-sur-Yvette (France); Donley, Jennifer [Los Alamos National Laboratory, Los Alamos, NM (United States)] [Los Alamos National Laboratory, Los Alamos, NM (United States); Gobat, R. [Laboratoire AIM-Paris-Saclay, CEA/DSM-CNRS-Universite Paris Diderot, Irfu/Service d'Astrophysique, CEA Saclay, Orme des Merisiers, F-91191 Gif-sur-Yvette (France)] [Laboratoire AIM-Paris-Saclay, CEA/DSM-CNRS-Universite Paris Diderot, Irfu/Service d'Astrophysique, CEA Saclay, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); and others

2013-01-01

238

Dopant titrating ion mobility spectrometry for trace exhaled nitric oxide detection.  

PubMed

Ion mobility spectrometry (IMS) is a promising non-invasive tool for the analysis of exhaled gas and exhaled nitric oxide (NO), a biomarker for diagnosis of respiratory diseases. However, the high moisture in exhaled gas always brings about extra overlapping ion peaks and results in poor identification ability. In this paper, p-benzoquinone (PBQ) was introduced into IMS to eliminate the interference of overlapping ion peaks and realize the selective identification of NO. The overlapping ions caused by moisture were titrated by PBQ and then converted to hydrated PBQ anions (C6H4[Formula: see text](H2O)n). The NO concentration could be determined by quantifying gas phase hydrated nitrite anions (N[Formula: see text](H2O)n), product ions of NO. Under optimized conditions, a limit of detection (LOD) of about 1.4?ppbv and a linear range of 10-200?ppbv were obtained for NO even in 100% relative humidity (RH) purified air. Furthermore, this established method was applied to measure hourly the exhaled NO of eight healthy volunteers, and real-time monitoring the exhaled NO of an esophageal carcinoma patient during radical surgery. These results revealed the potential of the current dopant titrating IMS method in the measurement of exhaled NO for medical disease diagnosis. PMID:25557839

Peng, Liying; Hua, Lei; Li, Enyou; Wang, Weiguo; Zhou, Qinghua; Wang, Xin; Wang, Changsong; Li, Jinghua; Li, Haiyang

2015-01-01

239

Correlation between ToBI test and in vivo titration for diphtheria and tetanus.  

PubMed

Alternatives to animal testing for quality control of biologicals have been a goal since 1959. Instituto Butantan has been developing such methods for quality control of biologicals for human use (vaccines and hyperimmune equine sera) for the last 13 years. In this paper we compare the modified ToBI test and the in vivo seroneutralization test to assess immunogenicity of diphtheria and tetanus vaccines and hyperimmune sera. Data from the last 10 years were statistically analyzed to compare the results for in vivo and in vitro titrations (diphtheria, n = 525 and tetanus, n = 455). The agreement between the tests depended on the serum titer range. For both diphtheria and tetanus components, the correlation and concordance coefficient was higher as the serum titer increased. Overall, the in vitro/in vivo titer ratio did not vary systematically over the range of measurements. These results indicate that although the in vitro ToBI test is not completely able to replace the in vivo serum titration, it is a useful tool to guide the tests during the production process, which can reduce the number of animals used for lot release. PMID:25458473

Quintilio, Wagner; Kapronezai, Josana; Alessandro de Freitas, Fábio

2015-01-01

240

Energetics of genome ejection from phage revealed by isothermal titration calorimetry  

NASA Astrophysics Data System (ADS)

It has been experimentally shown that ejection of double-stranded DNA from phage is driven by internal pressure reaching tens of atmospheres. This internal pressure is partially responsible for delivery of DNA into the host cell. While several theoretical models and simulations nicely describe the experimental data of internal forces either resisting active packaging or equivalently favoring spontaneous ejection, there are no direct energy measurements available that would help to verify how quantitative these theories are. We performed direct measurements of the enthalpy responsible for DNA ejection from phage ?, using Isothermal Titration Calorimetry. The phage capsids were ``opened'' in vitro by titrating ? into a solution with LamB receptor and the enthalpy of DNA ejection process was measured. In his way, enthalpy stored in ? was determined as a function of packaged DNA length comparing wild-type phage ? (48.5 kb) with a shorter ?-DNA length mutant (37.7 kb). The temperature dependence of the ejection enthalpy was also investigated. The values obtained were in good agreement with existing models and provide a better understanding of ds- DNA packaging and release mechanisms in motor-packaged viruses (e.g., tailed bacteriophages, Herpes Simplex, and adenoviruses).

Jeembaeva, Meerim; Jonsson, Bengt; Castelnovo, Martin; Evilevitch, Alex

2009-03-01

241

Hydration and Lyotropic Melting of Amphiphilic Molecules: A Thermodynamic Study Using Humidity Titration Calorimetry.  

PubMed

The hydration of the lipid 1-palmitoyl-2-oleoylphosphatidylcholine (POPC) and of the cationic detergent dodecyltrimethylammonium bromide (DTAB) has been studied by means of isothermal titration calorimetry (ITC), gravimetry, and infrared (IR) spectroscopy. During the experiments films of the amphiphiles are perfused by an inert gas of variable relative humidity. The measurement of adsorption heats using ITC represents a new adaptation of adsorption calorimetry which has been called the humidity titration technique. This method yields the partial molar enthalpy of water upon adsorption. It is found to be endothermic with respect to the molar enthalpy of water on condensation for the water molecules which interact directly with the headgroups of POPC and DTAB. Consequently, the spontaneous hydration of the amphiphiles is entropy driven in an aqueous environment. IR spectroscopy shows that hydration is accompanied by the increase in the conformational and/or motional freedom of the amphiphilic molecules upon water binding. In particular, a lyotropic chain melting transition is induced at a certain characteristic relative humidity. This event is paralleled by the adsorption of water. The corresponding exothermic adsorption heat is consumed completely (POPC) or partially (DTAB) by the hydrocarbon chains upon melting. Differential scanning calorimetry was used as an independent method to determine transition enthalpies of the amphiphiles at a definite hydration degree. Water binding onto the headgroups is discussed in terms of hydrogen bonding and polar interactions. The adsorption isotherms yield a number of approximately 2.6 tightly bound water molecules per POPC and DTAB molecule. Copyright 1999 Academic Press. PMID:10607439

Binder; Kohlstrunk; Heerklotz

1999-12-15

242

A novel method for the determination of the degree of deacetylation of chitosan by coulometric titration.  

PubMed

A novel method to determine the degree of deacetylation of chitosan is described. In this method, the coulometric titrant OH- is generated by the electrolysis of water. The OH- reacted with the residual hydrochloric acid in chitosan solution and the degree of deacetylation was obtained by Faraday's law. The optimized experimental parameters in this study were 1.0 mol/L KCl as supporting electrolyte, 15.00 mA as the intensity of constant current, composite glass electrode as indicating electrode couples, double platinum generated electrode-platinum wire auxiliary electrode as working electrode pairs, pH 3.80 as the titration end-point. The degree of deacetylation in the four samples, which varied from 70 to 95% were measured. The results were similar to those from 1H NMR and the standard deviations were lower than 0.5%. With merit of simplicity, convenience, quickness, high accuracy and precision, automatic detection of titration end-point and low-cost, the proposed method will be very useful in the industrial production. PMID:25020083

Wang, Chao; Yuan, Fang; Pan, Jiabao; Jiao, Shining; Jin, Ling; Cai, Hongwei

2014-09-01

243

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

NASA Astrophysics Data System (ADS)

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 demonstration is based on the traditional determination of water hardness in which EDTA is used as the titrant that complexes Mg2+ and Ca2+ ions. The color change that signals the end of the titration represents the successful removal of the Mg2+ ions from the metallochromic indicator Calmagite. This removal is possible because the value of the formation constant of the [Mg(EDTA)]2- complex is about 3 orders of magnitude greater than that corresponding to the [Mg(Calmagite)]- complex. The color change from wine-red (metal-bound indicator) to blue (unbound indicator) can be seen clearly in a large classroom with the use of overhead projection.

Yappert, M. Cecilia; Dupre, Donald B.

1997-12-01

244

Quantitative analysis of citric acid/sodium hypophosphite modified cotton by HPLC and conductometric titration.  

PubMed

Isocratic HPLC was used in conjunction with conductometric titration to quantitatively examine the modification of cotton cellulose by citric acid (CA)/sodium hypophosphite (SHP). CA/SHP had been extensively used as a green crosslinking agent for enhancement of cellulose and other carbohydrate polymers without in-depth understanding of the mechanisms. The current study investigated all identifiable secondary polycarboxylic acids from CA decomposition in the CA/SHP-cellulose system under various curing conditions. It was found that CA decomposition was more sensitive to temperature compared with the desirable esterification reaction. Two crosslinking mechanisms, namely ester crosslinking and SHP crosslinking were responsible for the observed improvement in crease resistance of CA/SHP treated cotton fabrics. An oligomer of citraconic acid (CCA) and/or itaconic acid (IA) was identified as a possible contributor to fabric yellowing. Finally, the crease resistance of fabrics correlated strongly with CA preservation in polyol-added CA/SHP crosslinking systems. The dosage of polyol should be held below an inflexion point to keep the undesirable competition against cellulose minimum. The combination of HPLC and conductometric titration was demonstrated to be useful in studying the CA/SHP-cellulose crosslinking system. The findings have implications for better application of CA/SHP in polysaccharide modifications in general. PMID:25659676

Ye, Tao; Wang, Bijia; Liu, Jian; Chen, Jiangang; Yang, Yiqi

2015-05-01

245

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

Code of Federal Regulations, 2013 CFR

...2013-04-01 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)...

2013-04-01

246

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

247

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

Code of Federal Regulations, 2014 CFR

...2014-04-01 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)...

2014-04-01

248

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

Code of Federal Regulations, 2010 CFR

...MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES...2160 Discrete photometric chemistry analyzer for clinical use... A discrete photometric chemistry analyzer for clinical...components that may also serve as reaction units. (b)...

2010-04-01

249

To achieve the best of both worlds! Binocular Photometric Stereo  

E-print Network

shape These methods use a laser scanned shape as input. [e.g. Neheb 05] Multiview photometric stereo effectively at low textured flat areas. - 2 2 Soft-Compactness Obj. max(0, - 2 2 - 2 ) Compactness Structured light Cross section An input image Cross section Top view Our method Nehab et al. Cross section

Washington at Seattle, University of

250

Photometric study of two ? Cephei pulsators in eclipsing systems  

NASA Astrophysics Data System (ADS)

We present results of a photometric study of the young southern open cluster Stock 14. This cluster is known to contain two eclipsing systems with presumed ? Cephei components, HD 101794 and HD 101838. We confirm variability due to pulsations and eclipses in both targets and announce the discovery of other variable stars in the observed field.

Drobek, D.; Pigulski, A.; Shobbrook, R. R.; Narwid, A.

2010-12-01

251

The Properties of Cataclysmic Variables In Photometric HSurveys  

Microsoft Academic Search

We report on the properties of 71 known cataclysmic variables (CVs) in photomet- ric Hemission line surveys. Our study is motivated by the fact that the Isaac Newton Telescope (INT) Photometric HSurvey of the northern galactic plane (IPHAS) will soon provide r', iand narrow-band Hmeasurements down to r' ? 20 for all northern objects between ?5o < b < +5o.

A. R. Witham; C. Knigge; B. T. Gansicke; A. Aungwerojwit; R. L. M. Corradi; J. E. Drew; R. Greimel; P. J. Groot; L. Morales-Rueda; E. R. Rodriguez-Flores; P. Rodriguez-Gil; D. Steeghs

2008-01-01

252

Photometric observations of facular contrasts near the solar limb  

Microsoft Academic Search

Digital, photometric images of several active regions near the solar limb made with 1.5 A effective bandpass at 6264 A are analyzed. From three to ten images were made per day on several days during 1983, 1984, and 1987 with the San Fernando Observatory 28 cm vacuum solar telescope and spectroheliograph and 512 element Reticon linear diode arrays. Pixel spacing

J. K. Lawrence; G. A. Chapman

1988-01-01

253

THE FUTURE OF PHOTOMETRIC, SPECTROPHOTOMETRIC AND POLARIMETRIC STANDARDIZATION  

E-print Network

Stratospheric Observatory for Infrared Astronomy/Universities Space Research Association, NASA Ames Research Series, Vol. 999, 2007 C. Sterken Steps Toward a Common Near-Infrared Photometric System A. T. Tokunaga Institute for Astronomy, University of Hawaii, 2680 Woodlawn Dr., Honolulu, HI 96822 W. D. Vacca

Tokunaga, Alan

254

Attachment to a personal computer to automate photometric measurements  

SciTech Connect

The unit is designed to automate spectrophotometer measurements of the night sky and man-made disturbances in the ionosphere produced during active space experiments. The photometric facility with a filter shuffler includes two movable optical units set on a turning device and a personal computer with the attachment.

Vakulenko, A.I.; Lapchuk, V.P.

1995-06-01

255

IMPA Minicourse Summer 2005 Photometric Calibration of Digital  

E-print Network

Michael Goesele Specialized & General Purpose Tools specialized tools spectrophotometer glossmeter haze Spectrophotometer illuminates an object under an angle of 45° observes it along the normal direction performs Goesele Spectrophotometer Photometric Calibration of Digital Cameras for Image-Based Techniques Michael

Goesele, Michael

256

Augmenting Depth Camera Output Using Photometric Stereo Robert Anderson  

E-print Network

containing the high frequency information of a normal map and the low frequency information from a depth mapAugmenting Depth Camera Output Using Photometric Stereo Robert Anderson Department of Engineering Department of Engineering University of Cambridge Abstract We present a system for augmenting depth cam- era

Martin, Ralph R.

257

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

258

astroph/9703058 Towards More Precise Photometric Redshifts: Calibration Via  

E-print Network

Photometry Robert J. Brunner 1;2 , Andrew J. Connolly 1 , and Alexander S. Szalay 1 rbrunner@pha.jhu.edu, ajc type (Connolly et al. 1995). Using recently acquired deep CCD photometry in existing, published. Furthermore, from our CCD photometry and the published redshifts, we have quantified the photometric

Bershady, Matthew A.

259

Photometric NO/sub x/ analyzer helps surpass EPA standards  

SciTech Connect

A photometric analyzer helped Monsanto Company of Pensacola, Florida reduce stack emissions to a point where an observer could not tell the difference between a shutdown and normal plant operation. Oxides of nitrogen output levels have been kept within 200 ppm at typical production rates, well within EPA limits.

Johnson, L.H.

1983-10-01

260

Photoelectric observations and photometric orbit of BS Dra.  

NASA Astrophysics Data System (ADS)

Two-colour photoelectric observations (501 blue, 408 yellow) have been made in the period 1971 - 1978. Photometric elements were determined by Lavrov's method. The system has small orbital eccentricity. The primary star's limb darkening coefficient (0.4) is less than the theoretical one. The components have nearly identical luminosity. Absolute elements were determined with Popper's spectral orbit.

Botsula, R. A.

261

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

262

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 10 ng/mL, and the limits of quantification (LOQs) were between 4 and 30 ng/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

263

Photometric Supernova Cosmology with BEAMS and SDSS-II  

NASA Astrophysics Data System (ADS)

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 104 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 ? m , ?? 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 ?BEAMS 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, Renée; Kunz, Martin; Bassett, Bruce; Smith, Mat; Newling, James; Varughese, Melvin; Kessler, Rick; Bernstein, Joseph P.; Campbell, Heather; Dilday, Ben; Falck, Bridget; Frieman, Joshua; Kuhlmann, Steve; Lampeitl, Hubert; Marriner, John; Nichol, Robert C.; Riess, Adam G.; Sako, Masao; Schneider, Donald P.

2012-06-01

264

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

265

Planck 2013 results. VIII. HFI photometric calibration and mapmaking  

NASA Astrophysics Data System (ADS)

This paper describes the methods used to produce photometrically calibrated maps from the Planck High Frequency Instrument (HFI) cleaned, time-ordered information. HFI observes the sky over a broad range of frequencies, from 100 to 857 GHz. To obtain the best calibration accuracy over such a large range, two different photometric calibration schemes have to be used. The 545 and 857 GHz data are calibrated by comparing flux-density measurements of Uranus and Neptune with models of their atmospheric emission. The lower frequencies (below 353 GHz) are calibrated using the solar dipole. A component of this anisotropy is time-variable, owing to the orbital motion of the satellite in the solar system. Photometric calibration is thus tightly linked to mapmaking, which also addresses low-frequency noise removal. By comparing observations taken more than one year apart in the same configuration, we have identified apparent gain variations with time. These variations are induced by non-linearities in the read-out electronics chain. We have developed an effective correction to limit their effect on calibration. We present several methods to estimate the precision of the photometric calibration. We distinguish relative uncertainties (between detectors, or between frequencies) and absolute uncertainties. Absolute uncertainties lie in the range from 0.54% to 10% from 100 to 857 GHz. We describe the pipeline used to produce the maps from the HFI timelines, based on the photometric calibration parameters, and the scheme used to set the zero level of the maps a posteriori. We also discuss the cross-calibration between HFI and the SPIRE instrument on board Herschel. Finally we summarize the basic characteristics of the set of HFI maps included in the 2013 Planck data release.

Planck Collaboration; Ade, P. A. R.; Aghanim, N.; Armitage-Caplan, C.; Arnaud, M.; Ashdown, M.; Atrio-Barandela, F.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Battaner, E.; Benabed, K.; Benoît, A.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bertincourt, B.; Bielewicz, P.; Bobin, J.; Bock, J. J.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Boulanger, F.; Bridges, M.; Bucher, M.; Burigana, C.; Cardoso, J.-F.; Catalano, A.; Challinor, A.; Chamballu, A.; Chary, R.-R.; Chen, X.; Chiang, H. C.; Chiang, L.-Y.; Christensen, P. R.; Church, S.; Clements, D. L.; Colombi, S.; Colombo, L. P. L.; Combet, C.; Couchot, F.; Coulais, A.; Crill, B. P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R. D.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.-M.; Désert, F.-X.; Dickinson, C.; Diego, J. M.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Dupac, X.; Efstathiou, G.; Enßlin, T. A.; Eriksen, H. K.; Filliard, C.; Finelli, F.; Forni, O.; Frailis, M.; Franceschi, E.; Galeotta, S.; Ganga, K.; Giard, M.; Giardino, G.; Giraud-Héraud, Y.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Hansen, F. K.; Hanson, D.; Harrison, D.; Helou, G.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hornstrup, A.; Hovest, W.; Huffenberger, K. M.; Jaffe, A. H.; Jaffe, T. R.; Jones, W. C.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kisner, T. S.; Kneissl, R.; Knoche, J.; Knox, L.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lamarre, J.-M.; Lasenby, A.; Laureijs, R. J.; Lawrence, C. R.; Le Jeune, M.; Lellouch, E.; Leonardi, R.; Leroy, C.; Lesgourgues, J.; Liguori, M.; Lilje, P. B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Maffei, B.; Mandolesi, N.; Maris, M.; Marshall, D. J.; Martin, P. G.; Martínez-González, E.; Masi, S.; Massardi, M.; Matarrese, S.; Matthai, F.; Maurin, L.; Mazzotta, P.; McGehee, P.; Meinhold, P. R.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Moreno, R.; Morgante, G.; Mortlock, D.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C. B.; Nørgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; Osborne, S.; Oxborrow, C. A.; Paci, F.; Pagano, L.; Pajot, F.; Paladini, R.; Paoletti, D.; Partridge, B.; Pasian, F.; Patanchon, G.; Pearson, T. J.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Popa, L.; Poutanen, T.; Pratt, G. W.; Prézeau, G.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Reinecke, M.; Remazeilles, M.; Renault, C.; Ricciardi, S.; Riller, T.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Roudier, G.; Rusholme, B.; Santos, D.; Savini, G.; Scott, D.; Shellard, E. P. S.; Spencer, L. D.; Starck, J.-L.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sunyaev, R.; Sureau, F.; Sutton, D.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J. A.; Tavagnacco, D.; Techene, S.; Terenzi, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Umana, G.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Vittorio, N.; Wade, L. A.; Wandelt, B. D.; Yvon, D.; Zacchei, A.; Zonca, A.

2014-11-01

266

Photometric Reverberation Mapping using a Meter-class Telescope  

NASA Astrophysics Data System (ADS)

For the past several decades, mass estimates for supermassive black holes hosted by active galactic nuclei (AGNs) have been made using the reverberation mapping (RM) technique. This methodology has produced consistent results and has been used to establish several relations that link the characteristics of the host galaxy to the mass of the central black hole. Despite this success, there are less than 50 AGNs with black hole masses derived from RM. This low number is generally attributed to the difficulties in coordinating large blocks of telescope time for making the simultaneous photometric and spectroscopic observations. In addition, the spectroscopic observations generally require several months of nightly observations with moderate to large size telescopes.We have made photometric observations of several AGNs in selected filters in order to evaluate a photometric methodology for determining the lag time between the variations observed in the continuum and the response signal that is seen coming from the broad-line region (BLR) gas. This time delay represents the mean light travel time to the BLR, and is therefore a measurement of the mean BLR radius. In traditional RM campaigns, this time lag is combined with a measure of the width of the broad line to determine the velocity of the gas and then make a virial estimate of the black hole mass. We investigate results obtained using photometric time lags and a single epoch spectroscopic measurement of the line width in order to estimate the mass of the central black hole.We present results from our photometric observations of several target AGNs made with the West Mountain Observatory 0.9 m reflector during the spring and summer of 2014.This research was supported by the College of Physical and Mathematical Sciences at Brigham Young University as well as through a fellowship from the NASA Rocky Mountain Space Grant Consortium.

Carroll, Carla June; Joner, Michael D.

2015-01-01

267

Free-running ground-based photometric array imaging of transient luminous events  

Microsoft Academic Search

We present observations of transient luminous events (TLEs) recorded during a summer TLE observation campaign in 2008 at Langmuir Laboratory near Socorro, New Mexico. The campaign featured observations made by a free-running, ground-based multianode photometric array called the Photometric Imager of Precipitated Electron Radiation (PIPER). As a photometric array, PIPER has high (40 ?s) temporal resolution and enough spatial resolution

R. T. Newsome

2010-01-01

268

Improved methylene blue two-phase titration method for determining cationic surfactant concentration in high-salinity brine.  

PubMed

The methylene blue (MB) two-phase titration method is a rapid and efficient method for determining the concentrations of anionic surfactants. The point at which the aqueous and chloroform phases appear equally blue is called Epton's end point. However, many inorganic anions, e.g., Cl(-), NO3(-), Br(-), and I(-), can form ion pairs with MB(+) and interfere with Epton's end point, resulting in the failure of the MB two-phase titration in high-salinity brine. Here we present a method to extend the MB two-phase titration method for determining the concentration of various cationic surfactants in both deionized water and high-salinity brine (22% total dissolved solid). A colorless end point, at which the blue color is completely transferred from the aqueous phase to the chloroform phase, is proposed as titration end point. Light absorbance at the characteristic wavelength of MB is measured using a spectrophotometer. When the absorbance falls below a threshold value of 0.04, the aqueous phase is considered colorless, indicating that the end point has been reached. By using this improved method, the overall error for the titration of a permanent cationic surfactant, e.g., dodecyltrimethylammonium bromide, in deionized (DI) water and high-salinity brine is 1.274% and 1.322% with limits of detection (LOD) of 0.149 and 0.215 mM, respectively. Compared to the traditional acid-base titration method, the error of this improved method for a switchable cationic surfactant, e.g., tertiary amine surfactant (Ethomeen C12), is 2.22% in DI water and 0.106% with LOD of 0.369 and 0.439 mM, respectively. PMID:25365626

Cui, Leyu; Puerto, Maura; López-Salinas, José L; Biswal, Sibani L; Hirasaki, George J

2014-11-18

269

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

270

Complexation of ?-cyclodextrin with a gemini surfactant studied by isothermal titration microcalorimetry and surface tensiometry.  

PubMed

We report on the inclusion complex formation of ?-cyclodextrin (?CD) with a cocogem surfactant (counterion-coupled gemini surfactant; (bis(4-(2-alkyl)benzenesulfonate)-Jeffamine salt, abbreviated as ABSJ), studied by isothermal titration calorimetry (ITC) and surface tension (SFT) measurements. We measured the critical micelle concentration (cmc) of ABSJ in water by the two experimental techniques in the temperature range 283-343 K, and determined the thermodynamic parameters of the complex formation directly by ITC and indirectly by the SFT. The stoichiometry (N), the binding constant (K), and the enthalpy of complexation were determined, and the Gibbs free energy and the entropy term were calculated from the experimental data. A novel method is presented for the determination of N and K by using surface tensiometry. PMID:24846443

Benk?, Mária; Király, László A; Puskás, Sándor; Király, Zoltán

2014-06-17

271

Universal Real-Time PCR-Based Assay for Lentiviral Titration.  

PubMed

Lentiviral vectors are efficient vehicles for stable gene transfer in both dividing and non-dividing cells. This feature among others makes lentiviral vectors a powerful tool in molecular research. However, the use of lentiviruses in research studies and clinical trials requires a precise and validated titration method. In this study, we describe a qPCR-based approach for estimation of lentiviral vector titer (pLV-THM-GFP). The use of WPRE (Woodchuck Hepatitis Virus Posttranscriptional Regulatory Element) and albumin genes as templates for an SYBR green-based real-time qPCR method allows for a rapid, sensitive, reproducible, and accurate assessment of lentiviral copy number at an integrated lentiviral DNA level. Furthermore, this optimization enables measurement of lentiviral concentration even in very poor quality and small quantity material. Consequently, this approach provides researchers with a tool to perform low-cost assessment with highly repeatable results. PMID:25370825

Barczak, Wojciech; Suchorska, Wiktoria; Rubi?, B?a?ej; Kulcenty, Katarzyna

2015-02-01

272

Thermodynamic signature of secondary nano-emulsion formation by isothermal titration calorimetry.  

PubMed

The stabilization of oil in water nano-emulsions by means of a polymer coating is extremely important; it prolongs the shelf life of the product and makes it suitable for a variety of applications ranging from nutraceutics to cosmetics and pharmaceutics. To date, an effective methodology to assess the best formulations in terms of thermodynamic stability has yet to be designed. Here, we perform a complete physicochemical characterization based on isothermal titration calorimetry (ITC) compared to conventional dynamic light scattering (DLS) to identify polymer concentration domains that are thermodynamically stable and to define the degree of stability through thermodynamic functions depending upon any relevant parameter affecting the stability itself, such as type of polymer coating, droplet distance, etc. For instance, the method was proven by measuring the energetics in the case of two different biopolymers, chitosan and poly-L-lysine, and for different concentrations of the emulsion coated with poly-L-lysine. PMID:25396753

Fotticchia, Iolanda; Fotticchia, Teresa; Mattia, Carlo Andrea; Netti, Paolo Antonio; Vecchione, Raffaele; Giancola, Concetta

2014-12-01

273

Near infrared spectral changes of cytochrome aa3 during potentiometric titrations.  

PubMed Central

Singular value decomposition (SVD) was used to deconvolute the spectral changes occurring in the near infrared region during potentiometric titrations of cytochrome aa3. Overall oxidized minus reduced difference spectra revealed a broad absorbance feature centered near 830 nm with an apparent Em near 250 mV. However, SVD did not isolate any spectral species with an absorbance centered near 830 nm. It was found that the spectral changes occurring in the wavelength region from 650 to 950 nm were associated mainly with cytochromes a and a3. It was concluded that the absorbance at 830 nm should not be used as an independent measure of the concentration of CuA in cytochrome aa3. PMID:7696488

Hendler, R W; Harmon, P A; Levin, I W

1994-01-01

274

Applications of Isothermal Titration Calorimetry in Biophysical Studies of G-quadruplexes  

PubMed Central

G-quadruplexes are higher-order nucleic acids structures formed by G-rich sequences that are stabilized by tetrads of hydrogen-bonded guanine bases. Recently, there has been growing interest in the study of G-quadruplexes because of their possible involvement in many biological processes. Isothermal titration calorimetry (ITC) has been proven to be a useful tool to study the energetic aspects of G-quadruplex interactions. Particularly, ITC has been applied many times to determine the thermodynamic properties of drug-quadruplex interactions to screening among various drugs and to address drug design. In the present review, we will focus on the ITC studies of G-quadruplex structures and their interaction with proteins and drugs and the most significant results will be discussed. PMID:19742177

Pagano, Bruno; Mattia, Carlo Andrea; Giancola, Concetta

2009-01-01

275

DNA heats up : Energetics of genome ejection from phage revealed by isothermal titration calorimetry  

E-print Network

Most bacteriophages are known to inject their double-stranded DNA into bacteria upon receptor binding in an essentially spontaneous way. This downhill thermodynamic process from the intact virion toward the empty viral capsid plus released DNA is made possible by the energy stored during active packaging of the genome into the capsid. Only indirect measurements of this energy have been available until now using either single-molecule or osmotic suppression techniques. In this paper, we describe for the first time the use of isothermal titration calorimetry to directly measure the heat released (or equivalently the enthalpy) during DNA ejection from phage lambda, triggered in solution by a solubilized receptor. Quantitative analyses of the results lead to the identification of thermodynamic determinants associated with DNA ejection. The values obtained were found to be consistent with those previously predicted by analytical models and numerical simulations. Moreover, the results confirm the role of DNA hydration in the energetics of genome confinement in viral capsids.

Meerim Jeembaeva; B. Jönsson; Martin Castelnovo; Alex Evilevitch

2010-01-06

276

Automatic technique for simultaneous H 2 and H 2O titration in MOX fuels  

NASA Astrophysics Data System (ADS)

A new and direct automatic method has been developed to measure the residual H 2 content of MOX fuel to be irradiated in a PWR. The sources of hydrogen in the pellets are either free hydrogen or moisture and can play an important role in the possible in-pile corrosion of the zircaloy cladding. The method is based on the simultaneous determinations of water with an hygrometrie probe and of hydrogen by a thermal conductivity cell and allows an original check of the two impurities concentrations. The entire set-up is fully computerized (weighing, titrating and display of results) and leads to an accuracy better than 0.1 ?gH2/ g ( U, Pu) O2 which fits the required PWR specification.

Bonnerot, J. M.; Warin, D.

1991-02-01

277

Heats of Mixing Using an Isothermal Titration Calorimeter: Associated Thermal Effects  

PubMed Central

The correct determination of the energy generated or absorbed in the sample cell of an Isothermal Titration Calorimeter (ITC) requires a thorough analysis of the calorimetric signal. This means the identification and quantification of any thermal effect inherent to the working method. In this work, it is carried out a review on several thermal effects, studied by us in previous work, and which appear when an ITC is used for measuring the heats of mixing of liquids in a continuous mode. These effects are due to: (i) the difference between the temperature of the injected liquid and the temperature of the mixture during the mixing process, (ii) the increase of the liquid volume located in the mixing cell and (iii) the stirring velocity. Besides, methods for the identification and quantification of the mentioned effects are suggested. PMID:19742175

de Rivera, Manuel Rodríguez; Socorro, Fabiola; Matos, José S.

2009-01-01

278

Titration biosensors for the estimation of the biochemical nitrate demand of municipal and industrial wastes.  

PubMed

An anoxic titrimetric test was investigated for measuring denitrification potential of different wastewaters, both municipal and industrial, and to quantify the denitrifying activity in an activated sludge system. The method measures the amount of acid that is required to maintain the pH set-point value in a batch denitrification experiment, and it was performed using a DENICON (denitrification controller) biosensor. The amount of acid is proportional to the nitrate used to oxidise the biodegradable chemical oxygen demand present in the wastewater, while the acid consumption rate is used to derive the denitrifying activity. The wastewaters tested were a municipal wastewater (MW), an industrial-municipal wastewater (MIW; 70% and 30%, respectively), and four industrial wastewaters drawn from an ice-cream factory (IW1), a beet-sugar factory (IW2), a brewery (IW3), and a tuna cannery industry (IW4). Good correlation between titration data and analyses was found. PMID:15856352

Onnis, A; Carucci, A; Cappai, G

2006-03-01

279

Whipple Procedure  

MedlinePLUS

... Goggins Lab Sol Goldman Center Discussion Board The Whipple Procedure Also called a pancreaticoduodenectomy, which is generally ... operation was first described by .Dr. Alan O. Whipple of New York Memorial Hospital (now called Memorial ...

280

THE PHOTOMETRIC CLASSIFICATION SERVER FOR Pan-STARRS1  

SciTech Connect

The Pan-STARRS1 survey is obtaining multi-epoch imaging in five bands (g{sub P1} r{sub P1} i{sub P1} z{sub P1} y{sub P1}) over the entire sky north of declination -30 deg. We describe here the implementation of the Photometric Classification Server (PCS) for Pan-STARRS1. PCS will allow the automatic classification of objects into star/galaxy/quasar classes based on colors and the measurement of photometric redshifts for extragalactic objects, and will constrain stellar parameters for stellar objects, working at the catalog level. We present tests of the system based on high signal-to-noise photometry derived from the Medium-Deep Fields of Pan-STARRS1, using available spectroscopic surveys as training and/or verification sets. We show that the Pan-STARRS1 photometry delivers classifications and photometric redshifts as good as the Sloan Digital Sky Survey (SDSS) photometry to the same magnitude limits. In particular, our preliminary results, based on this relatively limited data set down to the SDSS spectroscopic limits, and therefore potentially improvable, show that stars are correctly classified as such in 85% of cases, galaxies in 97%, and QSOs in 84%. False positives are less than 1% for galaxies, Almost-Equal-To 19% for stars, and Almost-Equal-To 28% for QSOs. Moreover, photometric redshifts for 1000 luminous red galaxies up to redshift 0.5 are determined to 2.4% precision (defined as 1.48 Multiplication-Sign Median|z{sub phot} - z{sub spec}|/(1 + z)) with just 0.4% catastrophic outliers and small (-0.5%) residual bias. For bluer galaxies up to the same redshift, the residual bias (on average -0.5%) trend, percentage of catastrophic failures (1.2%), and precision (4.2%) are higher, but still interestingly small for many science applications. Good photometric redshifts (to 5%) can be obtained for at most 60% of the QSOs of the sample. PCS will create a value-added catalog with classifications and photometric redshifts for eventually many millions of sources.

Saglia, R. P.; Bender, R.; Seitz, S.; Senger, R.; Snigula, J.; Phleps, S.; Wilman, D. [Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Postfach 1312, 85741 Garching (Germany); Tonry, J. L.; Burgett, W. S.; Chambers, K. C.; Heasley, J. N.; Kaiser, N.; Magnier, E. A.; Morgan, J. S. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Greisel, N. [University Observatory Munich, Ludwig-Maximilians Universitaet, Scheinerstrasse 1, 81679 Munich (Germany); Bailer-Jones, C. A. L.; Klement, R. J.; Rix, H.-W.; Smith, K. [Max Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany); Green, P. J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); and others

2012-02-20

281

Photometric calibration of the Supernova Legacy Survey fields  

NASA Astrophysics Data System (ADS)

Aims: We present the photometric calibration of the Supernova Legacy Survey (SNLS) fields. The SNLS aims at measuring the distances to SNe Ia at (0.3 < z < 1) using MegaCam, the 1 deg2 imager on the Canada-France-Hawaii Telescope (CFHT). The uncertainty affecting the photometric calibration of the survey dominates the systematic uncertainty of the key measurement of the survey, namely the dark energy equation of state. The photometric calibration of the SNLS requires obtaining a uniform response across the imager, calibrating the science field stars in each survey band (SDSS-like ugriz bands) with respect to standards with known flux in the same bands, and binding the calibration to the UBVRI Landolt standards used to calibrate the nearby SNe from the literature necessary to produce cosmological constraints. Methods: The spatial non-uniformities of the imager photometric response are mapped using dithered observations of dense stellar fields. Photometric zero-points against Landolt standards are obtained. The linearity of the instrument is studied. Results: We show that the imager filters and photometric response are not uniform and publish correction maps. We present models of the effective passbands of the instrument as a function of the position on the focal plane. We define a natural magnitude system for MegaCam. We show that the systematics affecting the magnitude-to-flux relations can be reduced if we use the spectrophotometric standard star BD +17 4708 instead of Vega as a fundamental flux standard. We publish ugriz catalogs of tertiary standards for all the SNLS fields. 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 the Canadian Astronomy Data Centre as part of the Canada-France-Hawaii Telescope Legacy Survey, a collaborative project of NRC and CNRS. Tables 13-22 and D.1-D.3 are also available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/506/999

Regnault, N.; Conley, A.; Guy, J.; Sullivan, M.; Cuillandre, J.-C.; Astier, P.; Balland, C.; Basa, S.; Carlberg, R. G.; Fouchez, D.; Hardin, D.; Hook, I. M.; Howell, D. A.; Pain, R.; Perrett, K.; Pritchet, C. J.

2009-11-01

282

Photometric Imaging of the Moon from the Robotic Lunar Observatory  

NASA Astrophysics Data System (ADS)

As part of the calibration program for the NASA Earth Observing System (part of NASA's Earth Science Enterprise), the U.S. Geological Survey operates the Robotic Lunar Observatory (ROLO). The ROLO project is designed to produce a photometric model of the nearside lunar surface for all phase and libration angles visible from Flagstaff [2]. Goals for this photometric model are 2.5 % absolute and 1.0% relative uncertainty. Although the model is principally intended to produce radiance images of the Moon for use in calibration of Earth-orbiting spacecraft, the ROLO data and model will also provide important information for studies of the lunar soil. Instrumentation: An astronomical observatory dedicated to the radiometry of the Moon has been constructed on the campus of the U.S. Geological Survey Flagstaff Field Station in Arizona. Two separate camera systems are attached to a single telescope mount and boresighted to the same pointing direction. The visible/near infrared (VNIR) camera uses a 512 x 512 pixel CCD and 23 intermediate width interference filters for wavelength selection. The shortwave infrared (SWIR) camera uses a 256 x 256 pixel cooled-HgCdTe infrared array and nine intermediate-width interference filters. Table I and Fig. I provide information on the instrumental passbands. Separate 20-cm-diameter Ritchey-Cretien telescopes are provided for the two cameras. The optics are designed to image the entire Moon within each camera's field of view, resulting in instrument pixel scales of 4 and 8 arcsec /pixel (about 7.4 and 15 km/pixel for the sub-Earth point on the Moon) for VNIR and SWIR respectively. Detailed information on the instrumentation can be found in Anderson et al. Observations: Routine imaging has been in progress since late 1995 for VNIR and late 1997 for SWIR, and is expected to continue through at least 2002. ROLO observes the Moon every clear night between the first and last quarter phases of the moon. On such nights, the Moon is imaged through all 32 filters at half-hour intervals during the time that the Moon is above the 60 deg. zenith angle. Observations of standard stars to measure atmospheric extinction and detector responsivity drifts occupy the remainder of the nighttime. Measurements of the dark current and detector bias levels are made during the dusk and dawn periods for VNIR and throughout the night for SWIR. Flat field corrections and absolute radiance calibrations are provided through observations of a Spectralon plate illuminated by a NIST-traceable 1000 W FEL lamp. Raw data are converted to ISIS cubes and stored on CD-ROM. Detailed information on the observing procedure is also found. As the development of data-reduction software for the ROLO project progresses and additional data are accumulated, the raw data are repeatedly processed into a calibrated form. Corrections for instrument response characteristics, photon scattering processes, and atmospheric extinction are applied to the raw lunar images to produce exoatmospheric radiance images of the Moon. These images are then transformed to a fixed selenographic-grid projection designed to accommodate all of the possible viewing geometries of the ROLO telescope. A preliminary discussion of results for the total irradiance of the Moon derived from ROLO VNIR images acquired through April 1998 was published by Kieffer and Anderson. At that time, difficulties in adequately determining the atmospheric extinction limited the accuracy of the derived lunar irradiance values. Significant improvements in the reduction software have been developed since that time and measurement scatter is expected to be reduced to approximately = or <2% for the data-processing run planned for the summer of 1999. As of June 1999 , ROLO has acquired over 2200 cubes of raw Moon images with VNIR and over 1200 cubes with SWIR. By 2002, ROLO expects to have acquired roughly 3500 images of the Moon through each VNIR filter and nearly 3000 images through each SWIR filter, or more than 100,000 absolutely calibrated images of the Moon. These data are used to create p

Anderson, J. M.; Kieffer, H. H.

1999-01-01

283

Time Resolved Photometric and Spectroscopic Analysis of Chemically Peculiar Stars  

NASA Astrophysics Data System (ADS)

Here we present the report on the ``Nainital-Cape survey'' research project aiming to search for and study the pulsational variability of main-sequence chemically peculiar (CP) stars. For this study, the time-series photometric observations of the sample stars were carried out at the 1.04 m ARIES telescope (India), while the high-resolution spectroscopic and spectro-polarimetric observations were carried out at the the 6.0 m Russian telescope. Under this project, we have recently found clear evidence of photometric variability in the Am star HD 73045, which is likely to be pulsating in nature with a period of about 36 min, hence adding a new member to the family of the ? Scuti pulsating variables that have peculiar abundances.

Joshi, Santosh; Joshi, Gireesh C.; Joshi, Y. C.; Aggrawal, Rahul

2015-01-01

284

Photometric Reverberation Mapping with a Small Aperture Telescope  

NASA Astrophysics Data System (ADS)

We present photometric observations of a sample of bright, broad-line AGN in order to monitor variability and verify their black hole masses using the photometric reverberation mapping technique. Observations were taken, primarily remotely, using the 20-inch telescope at the Murillo Family Observatory, a campus-based observatory located on the outskirts of the Southern California metro area, in both monitored and automated mode nightly in BVRI over a period of 2-5 months. We will show the viability of such a technique for small-aperture telescopes in bright-sky locations and discuss the possibilities of extending this program in the future. We also note that undergraduate students (both from 4-year and community colleges) have been and will continue to be instrumental in the success of similar research programs at CSUSB.

Hood, Carol E.; Rivera, Noah I.; Thackeray-Lacko, Beverly; Powers, Randy M.; Stuckey, Harrison; Watson, Rene; Hood, Michael A.

2015-01-01

285

The unique eclipsing system KH 15D: New photometric data  

NASA Astrophysics Data System (ADS)

We present results of photometric observations of the young eclipsing system KH 15D made during two observational seasons, 2002-2004. A comparison of our data with the earlier results of Hamilton et al. and Herbst et al. reveals the existence of a multiyear photometric trend in the brightness: over a period of 5 years the brightness of the system in the Ic band decreased by almost 1 stellar magnitude. It is also shown that the systematic variations in the eclipse parameters reported by Herbst et al. continue to the present. The shape of the light curve has not changed significantly and, as before, it is characterized by a slight brightening in the central portion of the eclipses. These results are discussed in the context of current models for KH 15D.

Barsunova, O. Yu.; Grinin, V. P.; Sergeev, S. G.

2005-01-01

286

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

287

Photometric Redshift with Bayesian Priors on Physical Properties of Galaxies  

E-print Network

We present a proof-of-concept analysis of photometric redshifts with Bayesian priors on physical properties of galaxies. This concept is particularly suited for upcoming/on-going large imaging surveys, in which only several broad-band filters are available and it is hard to break some of the degeneracies in the multi-color space. We construct model templates of galaxies using a stellar population synthesis code and apply Bayesian priors on physical properties such as stellar mass and star formation rate. These priors are a function of redshift and they effectively evolve the templates with time in an observationally motivated way. We demonstrate that the priors help reduce the degeneracy and deliver significantly improved photometric redshifts. Furthermore, we show that a template error function, which corrects for systematic flux errors in the model templates as a function of rest-frame wavelength, delivers further improvements. One great advantage of our technique is that we simultaneously measure redshifts...

Tanaka, Masayuki

2015-01-01

288

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

289

Photometric properties of resolved and unresolved magnetic elements  

E-print Network

We investigate the photometric signature of magnetic flux tubes in the solar photosphere. We developed two dimensional, static numerical models of isolated and clustered magnetic flux tubes. We investigated the emergent intensity profiles at different lines-of-sight for various spatial resolutions and opacity models. We found that both geometric and photometric properties of bright magnetic features are determined not only by the physical properties of the tube and its surroundings, but also by the particularities of the observations, including the line/continuum formation height, the spatial resolution and the image analyses techniques applied. We show that some observational results presented in the literature can be interpreted by considering bright magnetic features to be clusters of smaller elements, rather than a monolithic flux tube.

Serena Criscuoli; Mark Rast

2008-12-09

290

A Photometric Classification of the SAGE LMC Point Source Catalog  

NASA Astrophysics Data System (ADS)

The Spitzer SAGE Large Magellanic Cloud (LMC) photometric catalog lists over 7.2 million sources detected with the Spitzer space telescope. This catalog has been cross-correlated with the near-IR 2MASS and IRSF surveys, as well as with optical photometry from the MCPS database. This combined catalog is an invaluable tool for the study of LMC stellar populations, and to understand the life cycle of gas and dust in the LMC. To fully leverage the broad wavelength coverage of this database, we have developed a novel technique for the photometric classification of the SAGE LMC point source catalog, based on a weighted k-Nearest Neighbor method. This technique allows the classification of most LMC sources based on templates that have been identified spectroscopically, without a-priori assumptions about their spectral characteristics. We present here the details of our classification method, and the main results of our work.

Marengo, Massimo; Antoniou, V.; SAGE Collaboration

2014-01-01

291

Photometric investigation of the ISOPHOT C100 minimap mode  

NASA Astrophysics Data System (ADS)

As a possible concept to improve further the photometric accuracy of ISOPHOT we propose to concentrate on well-defined homogeneous data sets extracted from the Archive and carry out investigations focused on the specific calibration issues of the sample. The improvement of the photometric quality and that of the final error are monitored by selecting and evaluating secondary standards from the sample. In this contribution we describe the proposed general scheme and present -- as an example -- the analysis of 354 minimap observations of normal stars obtained at 60, 90 and 100?m with the C100 detector. In the analysis first we determine measurement uncertainties characteristic of the OLP V10 data processing, and then check the improvements achieved by introducing the newly developed dynamic transient correction.

Moór, Attila; Ábrahám, Péter; Kiss, Csaba; Héraudeau, Phillippe; del Burgo, Carlos

2003-02-01

292

Reference method for total water in lint cotton by automated oven drying combined with volumetric Karl Fischer titration  

Technology Transfer Automated Retrieval System (TEKTRAN)

In a preliminary study to measure total water in lint cotton we demonstrated that volumetric Karl Fischer Titration of moisture transported by a carrier gas from an attached small oven is more accurate than standard oven drying in air. The objective of the present study was to assess the measuremen...

293

A rapid Q-PCR titration protocol for adenovirus and helper-dependent adenovirus vectors that produces biologically relevant results  

PubMed Central

Adenoviruses are employed in the study of cellular processes and as expression vectors used in gene therapy. The success and reproducibility of these studies is dependent in part on having accurate and meaningful titers of replication competent and helper-dependent adenovirus stocks, which is problematic due to the use of varied and divergent titration protocols. Physical titration methods, which quantify the total number of viral particles, are used by many, but are poor at estimating activity. Biological titration methods, such as plaque assays, are more biologically relevant, but are time consuming and not applicable to helper-dependent gene therapy vectors. To address this, a protocol was developed called “infectious genome titration” in which viral DNA is isolated from the nuclei of cells ~3 h post-infection, and then quantified by Q-PCR. This approach ensures that only biologically active virions are counted as part of the titer determination. This approach is rapid, robust, sensitive, reproducible, and applicable to all forms of adenovirus. Unlike other Q-PCR-based methods, titers determined by this protocol are well correlated with biological activity. PMID:23624118

Gallaher, Sean D.; Berk, Arnold J.

2013-01-01

294

A rapid Q-PCR titration protocol for adenovirus and helper-dependent adenovirus vectors that produces biologically relevant results.  

PubMed

Adenoviruses are employed in the study of cellular processes and as expression vectors used in gene therapy. The success and reproducibility of these studies is dependent in part on having accurate and meaningful titers of replication competent and helper-dependent adenovirus stocks, which is problematic due to the use of varied and divergent titration protocols. Physical titration methods, which quantify the total number of viral particles, are used by many, but are poor at estimating activity. Biological titration methods, such as plaque assays, are more biologically relevant, but are time consuming and not applicable to helper-dependent gene therapy vectors. To address this, a protocol was developed called "infectious genome titration" in which viral DNA is isolated from the nuclei of cells ~3 h post-infection, and then quantified by Q-PCR. This approach ensures that only biologically active virions are counted as part of the titer determination. This approach is rapid, robust, sensitive, reproducible, and applicable to all forms of adenovirus. Unlike other Q-PCR-based methods, titers determined by this protocol are well correlated with biological activity. PMID:23624118

Gallaher, Sean D; Berk, Arnold J

2013-09-01

295

Anal. Chem. 1982, 54, 2117-2120 2117 validity of the ASV titration method. We are confident that  

E-print Network

Anal. Chem. 1982, 54, 2117-2120 2117 validity of the ASV titration method. We are confident. H. Anal. Chem.,preceding paper in this issue. Tuschall, J. R., Jr.; Brezonik, P. L. Anal. Chem. 1981, 53, 1986-1989. Shuman, M. S. Anal. Chem. 1982, 54, 998-1000. Brezonlk, P. L; Tuschall, J. R., Jr

Zare, Richard N.

296

Reference test methods for total water in lint cotton by Karl Fischer Titration and low temperature distillation  

Technology Transfer Automated Retrieval System (TEKTRAN)

In a study of comparability of total water contents (%) of conditioned cottons by Karl Fischer Titration (KFT) and Low Temperature Distillation (LTD) reference methods, we demonstrated a match of averaged results based on a large number of replications and weighing the test specimens at the same tim...

297

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

298

Photometric confirmation of the Encke division in Saturn's ring A  

Microsoft Academic Search

A physical model of the behavior of Saturn's satellite Iapetus passing through the shadow of the rings is discussed. The model is examined via computer simulation to give photometric confirmation of the Encke division in ring A. The actual event was observed with a two-channel sky-chopping photometer. Simultaneous pulse-counter output from the red and blue channels was integrated for 10-ms

H. J. Reitsema

1978-01-01

299

Photometric binary content in intermediate/old open clusters  

NASA Astrophysics Data System (ADS)

The stellar evolutionary models by Bertelli et al. (\\cite{Bertelli1994}) have been used to generate synthetic colour-magnitude diagrams (CMDs) of open clusters. A comparison of the synthetic integrated luminosity function (ILF) and synthetic colour distribution with the corresponding observed distributions is used to estimate the photometric binary content in three intermediate age open clusters, which is found to be about 30% in these clusters.

Sandhu, T. S.; Pandey, A. K.; Sagar, R.

2003-09-01

300

Preliminary Photometric Results for the 2003 Eclipse of Ee Cep  

Microsoft Academic Search

We report multicolour photometric observations of the 2003 eclipse of the long-period (5.6 yr) eclipsing binary EE Cep. Measurements were obtained with ten telescopes at eight observatories in four countries. In most cases, UBV(RI)C broad band filters have been used. The light curve shape shows that the obscuring body is an almost dark disk around a low-luminosity central object. However,

M. Mikolajewski; C. Galan; K. Gazeas; P. Niarchos; S. Zola; M. Kurpinska-Winiarska; M. Winiarski; A. Majewska; M. Siwak; M. Drahus; W. Waniak; A. Pigulski; G. Michalska; Z. Kolaczkowski; T. Tomov; M. Gromadzki; D. Graczyk; J. Osiwala; A. Majcher; M. Hajduk; M. Cikala; A. Zajczyk; D. Kolev; D. Dimitrov; E. Semkov; B. Bilkina; A. Dapergolas; L. Bellas-Velidis; B. Csak; B. Gere; P. Nemeth; G. Apostolovska

2005-01-01

301

Detailed Spectroscopic and Photometric Analysis of DQ White Dwarfs  

E-print Network

We present an analysis of spectroscopic and photometric data for cool DQ white dwarfs based on improved model atmosphere calculations. In particular, we revise the atmospheric parameters of the trigonometric parallax sample of Bergeron et al.(2001), and discuss the astrophysical implications on the temperature scale and mean mass, as well as the chemical evolution of these stars. We also analyze 40 new DQ stars discovered in the first data release of the Sloan Digital Sky Survey.

P. Dufour; P. Bergeron; G. Fontaine

2005-03-04

302

PhotoRApToR: PHOTOmetric Research APplication TO Redshifts  

NASA Astrophysics Data System (ADS)

PhotoRApToR (PHOTOmetric Research APplication TO Redshifts) solves regression and classification problems and is specialized for photo-z estimation. PhotoRApToR offers data table manipulation capabilities and 2D and 3D graphics tools for data visualization; it also provides a statistical report for both classification and regression experiments. The code is written in Java; the machine learning model is in C++ to increase the core execution speed.

Brescia, Massimo

2014-08-01

303

A physically-motivated photometric calibration of M dwarf metallicity  

Microsoft Academic Search

The location of M dwarfs in the (V-Ks)-MKs color-magnitude diagram (CMD) has been shown to correlate with metallicity. We demonstrate that previous empirical photometric calibrations of M dwarf metallicity exploiting this correlation systematically underestimate or overestimate metallicity at the extremes of their range. We improve upon previous calibrations in three ways. First, we use both a volume-limited and kinematically-matched sample

K. C. Schlaufman; Gregory Laughlin

2010-01-01

304

Asteroid photometric observations at Catania and Padova Observatories  

NASA Astrophysics Data System (ADS)

We present new photometric observations of 27 Euterpe, 173 Ino, 182 Elsa, 539 Pamina, 849 Ara, 2892 Filipenko, 3199 Nefertiti and 2004 UE, carried out between January 2003 and November 2004 at Catania Astrophysical Observatory and Padova Astronomical Observatory. The first determination of the synodic rotational period value of 2892 Filipenko and 2004 UE was obtained. For 182 Elsa, using the H-G magnitude relation (Bowell et al. 1989), we determined the absolute magnitude H and the slope parameter G.

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

305

Clinical outcomes during opioid titration following initiation with or conversion to Remoxy®, an extended-release formulation of oxycodone.  

PubMed

Intra- and interpatient variability in opioid response usually necessitates opioid therapy titration to optimally balance analgesia and side effects, whether initiating therapy or converting from another opioid. Remoxy® (King Pharmaceuticals, Inc., Bristol, TN, which was acquired by Pfizer Inc in March 2011) is an extended-release formulation of oxycodone designed to maintain its rate-controlling mechanism following physical and chemical manipulation. A recent phase 3 trial, which required dose titration following initiation or conversion to Remoxy, demonstrated the long-term safety and efficacy of Remoxy in relieving moderate to severe chronic pain. In this study, opioid-naïve patients were to be initiated on Remoxy 5 mg twice daily (10 mg total daily oxycodone dose) and opioid-experienced patients were to be converted to Remoxy at a dose equivalent to their previous opioid daily dose, determined from a conversion chart. A post-hoc analysis of study data provided clinically relevant information regarding initiation of or conversion to Remoxy. The intent-to-treat population (N=823) consisted of 429 opioid-experienced patients (52%) and 394 opioid-naïve patients (48%). A stable Remoxy dose (defined as the first dose administered on 2 consecutive visits, whereby on the first of these visits, further dose titration was deemed unnecessary) was achieved by 325 opioid-experienced patients (76%; mean, 2.2 titration steps), of whom 278 (86%) successfully converted to Remoxy according to the prospectively determined post-hoc definition (?4 titration steps). Of opioid-naïve patients, 300 (76%) reached a stable dose of Remoxy (mean, 2.2 titration steps), 253 (84%) of whom successfully initiated on Remoxy. Pain intensity decreased from baseline to study completion by approximately 35% for both opioid-experienced and opioid-naïve patients and adverse events were similar to those typically reported for opioids, with a higher incidence rate reported during titration (pre-stable dose period). These data provide important clinical information when initiating opioid-naïve patients on or converting opioid-experienced patients to Remoxy. PMID:21680999

Roland, Carl L; Setnik, Beatrice; Cleveland, Jody M; Brown, David A

2011-07-01

306

Photometric Study of the Possible Cool Quadruple System PY Virginis  

NASA Astrophysics Data System (ADS)

Complete CCD photometric light curves in BV(RI)c bands obtained in 2012 for the short-period close binary system PY Virginis are presented. A new photometric analysis with the Wilson—Van Hamme code shows that PY Vir is an A-type marginal contact binary system. The absolute parameters of PY Vir are derived using spectroscopic and photometric solutions. Combining new determined times of minimum light with others published in the literature, the O - C diagram of the binary star is investigated. A periodic variation, with a period of 5.22(±0.05) years and an amplitude of 0.0075(±0.0004) days, was discovered. Since the spectrum of a third component has been detected by Rucinski et al., we consider this cyclic period oscillation to be the result of the light-time effect due to the presence of a third body. This third component may also be a binary itself. Therefore, PY Vir should be a quadruple system composed of two cool-type binary systems. This system is a good astrophysical laboratory to study the formation and evolution of close binaries and multiple systems.

Zhu, L. Y.; Qian, S. B.; Liu, N. P.; Liu, L.; Jiang, L. Q.

2013-02-01

307

A comprehensive photometric study of the eclipsing binary EP Aurigae  

NASA Astrophysics Data System (ADS)

We present new observations for the eclipsing binary EP Aurigae, which were performed by using three small telescopes in China from 2003 December to 2014 January. With the updated 2003 version of the Wilson-Devinney code, the photometric elements were deduced from three sets of light curves. Based on all available eclipsing times, the orbital period changes were investigated. It is discovered that the (O-C) curve may show an existence of light-time effect due to an unseen third body, which was weakly identified by the photometric solution. The modulated period and amplitude of the cyclic variation are P3=71.2(±8.0) yr and A=0.0101(±0.0008) day, respectively. In the co-planar orbit with the binary system, the mass of the third body is M3=0.18(±0.02) M?. The photometric results imply that EP Aur is an Algol-type binary with a mass ratio of q=0.831(±0.004). Its primary component almost fills its Roche lobe. Therefore, EP Aur may consist of a normal main-sequence star and a cool Roche-lobe filling subgiant, which may be undergoing rapid mass transfer.

Li, H.-L.; Wei, J.-Y.; Yang, Y.-G.; Li, K.; Zhang, X.-B.

2015-02-01

308

Detector driver systems and photometric estimates for RIMAS  

NASA Astrophysics Data System (ADS)

The Rapid infrared IMAger-Spectrometer (RIMAS) is a rapid gamma-ray burst afterglow instrument that will provide photometric and spectroscopic coverage of the Y, J, H, and K bands. RIMAS separates light into two optical arms, YJ and HK, which allows for simultaneous coverage in two photometric bands. RIMAS utilizes two 2048 x 2048 pixel Teledyne HgCdTe (HAWAII-2RG) detectors along with a Spitzer Legacy Indium- Antimonide (InSb) guiding detector in spectroscopic mode to position and keep the source on the slit. We describe the software and hardware development for the detector driver and acquisition systems. The HAWAII- 2RG detectors simultaneously acquire images using Astronomical Research Cameras, Inc. driver, timing, and processing boards with two C++ wrappers running assembly code. The InSb detector clocking and acquisition system runs on a National Instruments cRIO-9074 with a Labview user interface and clocks written in an easily alterable ASCII file. We report the read noise, linearity, and dynamic range of our guide detector. Finally, we present RIMAS's estimated instrument efficiency in photometric imaging mode (for all three detectors) and expected limiting magnitudes. Our efficiency calculations include atmospheric transmission models, filter models, telescope components, and optics components for each optical arm.

Toy, Vicki L.; Kutyrev, Alexander S.; Lyness, Eric I.; Muench, Marius; Robinson, Frederick D.; Lotkin, Gennadiy N.; Capone, John I.; Veilleux, Sylvain; Moseley, Samuel H.; Gehrels, Neil A.; Vogel, Stuart N.

2014-07-01

309

The uBVI Photometric System. II. Standard Stars  

NASA Astrophysics Data System (ADS)

Paper I of this series described the design of a CCD-based photometric system that is optimized for ground-based measurements of the size of the Balmer discontinuity in stellar spectra. This ``uBVI'' system combines the Thuan-Gunn u filter with the standard Johnson-Kron-Cousins BVI filters and can be used to discover luminous yellow supergiants in extragalactic systems and post-asymptotic giant branch stars in globular clusters and galactic halos. In the present paper we use uBVI observations obtained on 54 nights with 0.9 m telescopes at Kitt Peak and Cerro Tololo to construct a catalog of standardized u magnitudes for standard stars taken from the 1992 catalog of Landolt. We describe the selection of our 14 Landolt fields and give details of the photometric reductions, including red leak and extinction corrections, transformation of all the observations onto a common magnitude system, and the establishment of the photometric zero point. We present a catalog of u magnitudes of 103 stars suitable for use as standards. We show that data obtained with other telescopes can be transformed to our standard system with better than 1% accuracy.

Siegel, Michael H.; Bond, Howard E.

2005-06-01

310

Empirical color transformations between SDSS photometry and other photometric systems  

NASA Astrophysics Data System (ADS)

Aims.We present empirical color transformations between the Sloan Digital Sky Survey (SDSS) ugriz photometry and the Johnson-Cousins UBVRI system and Becker's RGU system, respectively. Owing to the magnitude of data that is becoming available in the SDSS photometric system it is particularly important to be able to convert between this new system and traditional photometric systems. Unlike earlier published transformations we based our calculations on stars actually measured by the SDSS with the SDSS 2.5-m telescope. The photometric database of the SDSS provides in a sense a single-epoch set of "tertiary standards" covering more than one quarter of the sky. Our transformations should facilitate their use to easily and reliably derive the corresponding approximate Johnson-Cousins or RGU magnitudes. Methods: .The SDSS survey covers a number of areas that were previously established as standard fields in the Johnson-Cousins system, in particular, fields established by Landolt and by Stetson. We used these overlapping fields to create well-photometered star samples on which our calculated transformations are based. For the RGU photometry we used fields observed in the framework of the new Basel high-latitude field star survey. Results: .We calculated empirical color transformations between SDSS photometry and Johnson-Cousins UBVRI and Becker's RGU system. For all transformations we found linear relations to be sufficient. Furthermore we showed that the transformations between the Johnson-Cousins and the SDSS system have a slight dependence on metallicity.

Jordi, K.; Grebel, E. K.; Ammon, K.

2006-12-01

311

Computer-aided photometric analysis of dynamic digital bioluminescent images  

NASA Astrophysics Data System (ADS)

The paper deals with photometric and morphologic analysis of bioluminescent images obtained by registration of light radiated directly from some plant objects. Registration of images obtained from ultra-weak light sources by the single photon counting (SPC) technique is the subject of this work. The radiation is registered by use of a 16-bit charge coupled device (CCD) camera "Night Owl" together with WinLight EG&G Berthold software. Additional application-specific software has been developed in order to deal with objects that are changing during the exposition time. Advantages of the elaborated set of easy configurable tools named FCT for a computer-aided photometric and morphologic analysis of numerous series of quantitatively imperfect chemiluminescent images are described. Instructions are given how to use these tools and exemplified with several algorithms for the transformation of images library. Using the proposed FCT set, automatic photometric and morphologic analysis of the information hidden within series of chemiluminescent images reflecting defensive processes in poinsettia (Euphorbia pulcherrima Willd) leaves affected by a pathogenic fungus Botrytis cinerea is revealed.

Gorski, Zbigniew; Bembnista, T.; Floryszak-Wieczorek, J.; Domanski, Marek; Slawinski, Janusz

2003-04-01

312

Long-term photometric behaviour of outbursting AM CVn systems  

NASA Astrophysics Data System (ADS)

The AM CVn systems are a class of He-rich, post-period minimum, semidetached, ultracompact binaries. Their long-term light curves have been poorly understood due to the few systems known and the long (hundreds of days) recurrence times between outbursts. We present combined photometric light curves from the Lincoln Near Earth Asteroid Research, Catalina Real-Time Transient Survey, and Palomar Transient Factory synoptic surveys to study the photometric variability of these systems over an almost 10 yr period. These light curves provide a much clearer picture of the outburst phenomena that these systems undergo. We characterize the photometric behaviour of most known outbursting AM CVn systems and establish a relation between their outburst properties and the systems' orbital periods. We also explore why some systems have only shown a single outburst so far and expand the previously accepted phenomenological states of AM CVn systems. We conclude that the outbursts of these systems show evolution with respect to the orbital period, which can likely be attributed to the decreasing mass transfer rate with increasing period. Finally, we consider the number of AM CVn systems that should be present in modelled synoptic surveys.

Levitan, David; Groot, Paul J.; Prince, Thomas A.; Kulkarni, Shrinivas R.; Laher, Russ; Ofek, Eran O.; Sesar, Branimir; Surace, Jason

2015-01-01

313

Measurement of atmospheric OH by titration of near-IR fluorescent dyes  

NASA Technical Reports Server (NTRS)

Recent research has shown that certain polymethine dyes can be detected at ultratrace levels (greater than or equal to 6x10(exp -14) M) in solution by fluorimetry. These detection limits are possible because of the inherent sensitivity of fluorescence techniques, because the dyes fluoresce in the near infrared region where background interference is negligible, and because powerful infrared diode lasers are now available to improve the signal to noise ratio. Other work has shown that the hydroxyl radical destroys the ability of polymethine dyes to fluoresce. These observations form the basis for a new hydroxyl radical detector that is essentially a fluorometric titrator. Theoretically, the detector should show an acceptable sensitivity and response time. Assuming that the atmospheric HO concentration is about 10(exp -11) moles m(exp -3) (i.e. 10(exp 6) molecules cm(exp -3)), then 10 L of air 'titrated' with 20 mL of 10(exp -11) M dye solution (an easily detected concentration) should result in a drop in the fluorescent signal of 50 percent - a readily detectable change. At a flow rate of 3 L min(exp -1) the sampling time would be 3 minutes. The biggest potential problem is selectivity: other oxidants may also cause the fluorescence signal to be lost. The chemistry of polymethine dyes has not been studied in detail and so no quantitative data are available. However, a survey of the literature suggests that in general HO should react up to six orders of magnitude faster than HO2 and other radicals such as RO2 and RO. It should also react much more rapidly than H2O2 and O3. Thus it may be possible to discriminate kinetically against potential interfering substances. It was shown in the laboratory that 10(exp -4) M H2O2 has little effect on the absorption spectrum of the dye IR125 over a period of hours but that the band at 780 nm is slowly lost in water over a period of days even under argon in the dark. By contrast, DMSO solutions of IR125 are stable.

Betterton, Eric A.; Gast, Karl

1994-01-01

314

A titration approach to identify the capacity for starch digestion in milk-fed calves.  

PubMed

Calf milk replacers (MR) commonly contain 40% to 50% lactose. For economic reasons, starch is of interest as a lactose replacer. Compared with lactose, starch digestion is generally low in calves. It is, however, unknown which enzyme limits the rate of starch digestion. The objectives were to determine which enzyme limits starch digestion and to assess the maximum capacity for starch digestion in milk-fed calves. A within-animal titration study was performed, where lactose was exchanged stepwise for one of four starch products (SP). The four corn-based SP differed in size and branching, therefore requiring different ratios of starch-degrading enzymes for their complete hydrolysis to glucose: gelatinised starch (?-amylase and (iso)maltase); maltodextrin ((iso)maltase and ?-amylase); maltodextrin with ?-1,6-branching (isomaltase, maltase and ?-amylase) and maltose (maltase). When exceeding the animal's capacity to enzymatically hydrolyse starch, fermentation occurs, leading to a reduced faecal dry matter (DM) content and pH. Forty calves (13 weeks of age) were assigned to either a lactose control diet or one of four titration strategies (n=8 per treatment), each testing the stepwise exchange of lactose for one SP. Dietary inclusion of each SP was increased weekly by 3% at the expense of lactose and faecal samples were collected from the rectum weekly to determine DM content and pH. The increase in SP inclusion was stopped when faecal DM content dropped below 10.6% (i.e. 75% of the average initial faecal DM content) for 3 consecutive weeks. For control calves, faecal DM content and pH did not change over time. For 87% of the SP-fed calves, faecal DM and pH decreased already at low inclusion levels, and linear regression provided a better fit of the data (faecal DM content or pH v. time) than non-linear regression. For all SP treatments, faecal DM content and pH decreased in time (P<0.001) and slopes for faecal DM content and pH in time differed from CON; P<0.001 for all SP), but did not differ between SP treatments. Faecal DM content of SP-fed calves decreased by 0.57% and faecal pH by 0.32 per week. In conclusion, faecal DM content and pH sensitively respond to incremental inclusion of SP in calf MR, independently of SP characteristics. All SP require maltase to achieve complete hydrolysis to glucose. We therefore suggest that maltase activity limits starch digestion and that fermentation may contribute substantially to total tract starch disappearance in milk-fed calves. PMID:25205419

Gilbert, M S; van den Borne, J J G C; Berends, H; Pantophlet, A J; Schols, H A; Gerrits, W J J

2015-02-01

315

Cluster membership probabilities from proper motions and multi-wavelength photometric catalogues. I. Method and application to the Pleiades cluster  

NASA Astrophysics Data System (ADS)

Context. With the advent of deep wide surveys, large photometric and astrometric catalogues of literally all nearby clusters and associations have been produced. The unprecedented accuracy and sensitivity of these data sets and their broad spatial, temporal and wavelength coverage make obsolete the classical membership selection methods that were based on a handful of colours and luminosities. We present a new technique designed to take full advantage of the high dimensionality (photometric, astrometric, temporal) of such a survey to derive self-consistent and robust membership probabilities of the Pleiades cluster. Aims: We aim at developing a methodology to infer membership probabilities to the Pleiades cluster from the DANCe multidimensional astro-photometric data set in a consistent way throughout the entire derivation. The determination of the membership probabilities has to be applicable to censored data and must incorporate the measurement uncertainties into the inference procedure. Methods: We use Bayes' theorem and a curvilinear forward model for the likelihood of the measurements of cluster members in the colour-magnitude space, to infer posterior membership probabilities. The distribution of the cluster members proper motions and the distribution of contaminants in the full multidimensional astro-photometric space is modelled with a mixture-of-Gaussians likelihood. Results: We analyse several representation spaces composed of the proper motions plus a subset of the available magnitudes and colour indices. We select two prominent representation spaces composed of variables selected using feature relevance determination techniques based in Random Forests, and analyse the resulting samples of high probability candidates. We consistently find lists of high probability (p > 0.9975) candidates with ?1000 sources, 4 to 5 times more than obtained in the most recent astro-photometric studies of the cluster. Conclusions: Multidimensional data sets require statistically sound multivariate analysis techniques to fully exploit their scientific information content. Proper motions in particular are, as expected, critical for the correct separation of contaminants. The methodology presented here is ready for application in data sets that include more dimensions, such as radial and/or rotational velocities, spectral indices, and variability. Membership probability catalogs for the DANCe Pleiades data are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/563/A45

Sarro, L. M.; Bouy, H.; Berihuete, A.; Bertin, E.; Moraux, E.; Bouvier, J.; Cuillandre, J.-C.; Barrado, D.; Solano, E.

2014-03-01

316

Elucidation of ionic interactions in the protic ionic liquid solutions by isothermal titration calorimetry.  

PubMed

The strong hydrogen-bonded network noted in protic ionic liquids (PILs) may lead to stronger interactions of the ionic entities of PILs with solvents (water, methanol, ethylene glycol, dimethylsulfoxide (DMSO), N,N'-dimethylformamide (DMF)) as compared with those of aprotic ionic liquids (APILs). The PILs used in this work are 1-methylimidazolium tetrafluoroborate, 2-methylpyridinium tetrafluoroborate, and N-methylpyrrolodinium tetrafluoroborate in comparison to 1-butyl-3-methylimidazolium tetrafluoroborate, which is classified as an APIL. In this work, the excess partial molar enthalpy, H(E)IL obtained from isothermal calorimetric titrations at 298.15 K is used to probe the nature of interactions of the PIL cations with solvent molecules against those present in APIL-solvent systems. This work also reports interesting flip-flopping in the thermal behavior of these PIL-solvent systems depending upon the structure of the cationic ring of a PIL. In some cases, these flip-flops are the specific fingerprints for specific PILs in a common solvent environment. The excess partial molar enthalpy at infinite dilution, H(E,?)IL, of these PILs bears a critical dependence on the solvent properties. An analysis of relative apparent molar enthalpies, ?L, of the PIL solutions by the ion interaction model of Pitzer yields important information on ionic interactions of these systems. PMID:24650134

Rai, Gitanjali; Kumar, Anil

2014-04-17

317

Probing the binding of procyanidin B3 to human serum albumin by isothermal titration calorimetry  

NASA Astrophysics Data System (ADS)

Proanthocyanidins are a mixture of monomers, oligomers, and polymers of flavan-3-ols that are widely distributed in the plant kingdom. One of the most widely studied proanthocyanidins is procyanidin B3. In this study, the interaction between procyanidin B3 and human serum albumin (HSA) was investigated using isothermal titration calorimetry (ITC). Thermodynamic investigations reveal that the hydrogen bond and van der Waals force are the major binding forces in the binding of procyanidin B3 to HSA. The binding of procyanidin B3 to HSA is driven by favorable enthalpy and unfavorable entropy. The obtained binding constant for procyanidin B3 with HSA is in the intermediate range and the equilibrium fraction of unbound procyanidin B3 fu > 90% at the physiological concentration of HSA shows that procyanidin B3 can be stored and transported from the circulatory system to reach its target site. The stoichiometric binding number n approximately equals to 1, suggesting that one molecule of procyanidin B3 combines with one molecule of HSA and no more procyanidin B3 binding to HSA occurs at the concentration used in this study.

Li, Xiangrong; Yan, Yunhui

2015-02-01

318

Real-Time Monitoring of Membrane-Protein Reconstitution by Isothermal Titration Calorimetry  

PubMed Central

Phase diagrams offer a wealth of thermodynamic information on aqueous mixtures of bilayer-forming lipids and micelle-forming detergents, providing a straightforward means of monitoring and adjusting the supramolecular state of such systems. However, equilibrium phase diagrams are of very limited use for the reconstitution of membrane proteins because of the occurrence of irreversible, unproductive processes such as aggregation and precipitation that compete with productive reconstitution. Here, we exemplify this by dissecting the effects of the K+ channel KcsA on the process of bilayer self-assembly in a mixture of Escherichia coli polar lipid extract and the nonionic detergent octyl-?-d-glucopyranoside. Even at starting concentrations in the low micromolar range, KcsA has a tremendous impact on the supramolecular organization of the system, shifting the critical lipid/detergent ratios at the onset and completion of vesicle formation by more than 2-fold. Thus, equilibrium phase diagrams obtained for protein-free lipid/detergent mixtures would be misleading when used to guide the reconstitution process. To address this issue, we demonstrate that, even under such nonequilibrium conditions, high-sensitivity isothermal titration calorimetry can be exploited to monitor the progress of membrane-protein reconstitution in real time, in a noninvasive manner, and at high resolution to yield functional proteoliposomes with a narrow size distribution for further downstream applications. PMID:24354292

2013-01-01

319

Uncertainty evaluation in the chloroquine phosphate potentiometric titration: application of three different approaches.  

PubMed

A measurement result cannot be properly interpreted if not accompanied by its uncertainty. Several methods to estimate uncertainty have been developed. From those methods three in particular were chosen in this work to estimate the uncertainty of the Eu. Ph. chloroquine phosphate assay, a potentiometric titration commonly used in medicinal control laboratories. The famous error-budget approach (also called bottom-up or step-by-step) described by the ISO Guide to the expression of Uncertainty in Measurement (GUM) was the first method chosen. It is based on the combination of uncertainty contributions that have to be directly derived from the measurement process. The second method employed was the Analytical Method Committee top-down which estimates uncertainty through reproducibility obtained during inter-laboratory studies. Data for its application were collected in a proficiency testing study carried out by over 50 laboratories throughout Europe. The last method chosen was the one proposed by Barwick and Ellison. It uses a combination of precision, trueness and ruggedness data to estimate uncertainty. These data were collected from a validation process specifically designed for uncertainty estimation. All the three approaches presented a distinctive set of advantages and drawbacks in their implementation. An expanded uncertainty of about 1% was assessed for the assay investigated. PMID:16870384

Rodomonte, Andrea Luca; Montinaro, Annalisa; Bartolomei, Monica

2006-09-11

320

Adsorption of sodium dodecyl sulfate on functionalized graphene measured by conductometric titration.  

PubMed

We report on the adsorption of sodium dodecyl sulfate (SDS) onto functionalized graphene sheets (FGSs) in an aqueous system, measured at broad SDS and FGS concentration ranges by conductometric surfactant titration. At dilute SDS concentrations (<12 ?M in bulk solution), there is evidence of a counterion exchange between hydronium ions (from the dissociation of acidic chemical functionalities on FGS) and sodium ions coadsorbing with dodecyl sulfate monomers onto FGSs. We find that, for FGS with a carbon-to-oxygen ratio of ~18, monolayer adsorption of SDS on FGS reaches full surface coverage by ~12 ?M SDS. Additionally, the critical surface aggregation concentration (csac) for surface micelle formation on FGS is measured to be ~1.5 mM SDS. The transition from monolayer adsorption to surface micelle formation appears to occur at a similar SDS concentration on FGSs as on graphite, suggesting there is little difference in the surfactant adsorption behavior on both materials. We estimate that the FGS surface area available for SDS adsorption is ~600 m(2)/g, which is significantly less than expected for FGSs in suspension and indicates the presence of regions on FGS on which SDS adsorption does not occur. PMID:23734569

Hsieh, Andrew G; Punckt, Christian; Korkut, Sibel; Aksay, Ilhan A

2013-07-01

321

pH titration monitored by quantum cascade laser-based vibrational circular dichroism.  

PubMed

Vibrational circular dichroism (VCD) spectra of aqueous solutions of proline were recorded in the course of titrations from basic to acidic pH using a spectrometer equipped with a quantum cascade laser (QCL) as an infrared light source in the spectral range from 1320 to 1220 cm(-1). The pH-dependent spectra were analyzed by singular value decomposition and global fitting of a two-pK Henderson-Hasselbalch model. The analysis delivered relative fractions of the three different protonation species. Their agreement with the relative fractions obtained from performing the same analysis on pH-dependent Fourier transform infrared (FT-IR) and QCL-IR spectra validates the quantitative results from QCL-VCD. Global fitting of the pH-dependent VCD spectra of L-proline allowed for extraction of pure spectra corresponding to anionic, zwitterionic, and cationic L-proline. From a static experiment, only pure spectra of the zwitterion would be accessible in a straightforward way. A comparison to VCD spectra calculated for all three species led to assignment of vibrational modes that are characteristic for the respective protonation states. The study demonstrates the applicability of QCL-VCD both for quantitative evaluation and for qualitative interpretation of dynamic processes in aqueous solutions. PMID:24655319

Rüther, Anja; Pfeifer, Marcel; Lórenz-Fonfría, Víctor A; Lüdeke, Steffen

2014-04-10

322

Development of a rapid titration method for predicting optimal coagulant concentration for filled tofu.  

PubMed

A rapid titration method was developed for predicting the optimal coagulant concentration for making filled tofu. Cooked soymilk (350 mL, 20 degrees C) in a 400 mL beaker was stirred by a magnetic stirrer to form a swirl. The quick-acting coagulant solution (20.0 Brix) was added into the soymilk at 1.0 mL/min. The swirl depth decreased when the soymilk viscosity increased as a result of increasing the concentration of coagulant in the soymilk. At a suitable stirrer speed, the swirl finally disappeared but the soymilk still maintained rotation, and then the swirl reappeared after around 1 min. The critical point of coagulant concentration (CPCC) was calculated on the basis of the volume of coagulant consumed to get the swirl to disappear. The influences of several factors on the CPCC were investigated, including coagulant addition rate, soymilk temperature, soymilk concentration, soymilk volume, stir bar length, and container size. For validation, 33 soybean samples were used to determine their CPCCs and make filled tofus. The results indicated that CPCC was a characteristic parameter of soymilk and could be used as an effective indicator for predicting optimal coagulant concentration. PMID:12926861

Liu, Zhi-Sheng; Chang, K C

2003-08-27

323

Temperature modulation and quadrature detection for selective titration of two-state exchanging reactants.  

PubMed

Biological samples exhibit huge molecular diversity over large concentration ranges. Titrating a given compound in such mixtures is often difficult, and innovative strategies emphasizing selectivity are thus demanded. To overcome limitations inherent to thermodynamics, we here present a generic technique where discrimination relies on the dynamics of interaction between the target of interest and a probe introduced in excess. Considering an ensemble of two-state exchanging reactants submitted to temperature modulation, we first demonstrate that the amplitude of the out-of-phase concentration oscillations is maximum for every compound involved in a reaction whose equilibrium constant is equal to unity and whose relaxation time is equal to the inverse of the excitation angular frequency. Taking advantage of this feature, we next devise a highly specific detection protocol and validate it using a microfabricated resistive heater and an epifluorescence microscope, as well as labeled oligonucleotides to model species displaying various dynamic properties. As expected, quantification of a sought for strand is obtained even if interfering reagents are present in similar amounts. Moreover, our approach does not require any separation and is compatible with imaging. It could then benefit some of the numerous binding assays performed every day in life sciences. PMID:21355619

Zrelli, K; Barilero, T; Cavatore, E; Berthoumieux, H; Le Saux, T; Croquette, V; Lemarchand, A; Gosse, C; Jullien, L

2011-04-01

324

The properties of cataclysmic variables in photometric H? surveys  

NASA Astrophysics Data System (ADS)

We report on the properties of 71 known cataclysmic variables (CVs) in photometric H? emission-line surveys. Our study is motivated by the fact that the Isaac Newton Telescope (INT) Photometric H? Survey of the northern galactic plane (IPHAS) will soon provide r',i' and narrow-band H? measurements down to r' ~= 20 for all northern objects between - 5° < b < +5°. IPHAS thus provides a unique resource, both for studying the emission-line properties of known CVs and for constructing a new CV sample selected solely on the basis of H? excess. Our goal here is to carry out the first task and prepare the way for the second. In order to achieve this, we analyse data on 19 CVs already contained in the IPHAS data base and supplement this with identical observations of 52 CVs outside the galactic plane. Our key results are as follows: (i) the recovery rate of known CVs as H? emitters in a survey like IPHAS is ~=70 per cent; (ii) of the ~=30 per cent of CVs which were not recovered ~=75 per cent were clearly detected but did not exhibit a significant H? excess at the time of our observations; (iii) the recovery rate depends only weakly on CV type; (iv) the recovery rate depends only weakly on orbital period; (v) short-period dwarf novae tend to have the strongest H? lines. These results imply that photometric emission-line searches provide an efficient way of constructing CV samples that are not biased against detection of intrinsically faint, short-period systems.

Witham, A. R.; Knigge, C.; Gänsicke, B. T.; Aungwerojwit, A.; Corradi, R. L. M.; Drew, J. E.; Greimel, R.; Groot, P. J.; Morales-Rueda, L.; Rodriguez-Flores, E. R.; Rodriguez-Gil, P.; Steeghs, D.

2006-06-01

325

Intrinsic alignments of group and cluster galaxies in photometric surveys  

NASA Astrophysics Data System (ADS)

Intrinsic alignments of galaxies have been shown to contaminate weak gravitational lensing observables on linear scales, r > 10 h-1 Mpc, but studies of alignments in the non-linear regime have thus far been inconclusive. We present an estimator for extracting the intrinsic alignment signal of galaxies around stacked clusters of galaxies from multiband imaging data. Our estimator removes the contamination caused by galaxies that are gravitationally lensed by the clusters and scattered in redshift space due to photometric redshift uncertainties. It uses posterior probability distributions for the redshifts of the galaxies in the sample and it is easily extended to obtain the weak gravitational lensing signal while removing the intrinsic alignment contamination. We apply this algorithm to groups and clusters of galaxies identified in the Sloan Digital Sky Survey `Stripe 82' co-added imaging data over ˜150 deg2. We find that the intrinsic alignment signal around stacked clusters in the redshift range 0.1 < z < 0.4 is consistent with zero. In terms of the tidal alignment model of Catelan et al., we set joint constraints on the strength of the alignment and the bias of the lensing groups and clusters on scales between 0.1 and 10 h-1 Mpc, b_LC_1? _crit = -2_{-14}^{+14} × 10^{-4}. This constrains the contamination fraction of alignment to lensing signal to the range between [ - 18, 23] per cent below scales of 1 h-1 Mpc at 95 per cent confidence level, and this result depends on our photometric redshift quality and selection criteria used to identify background galaxies. Our results are robust to the choice of photometric band in which the shapes are measured (i and r) and to centring on the Brightest Cluster Galaxy or on the geometrical centre of the clusters.

Chisari, Nora Elisa; Mandelbaum, Rachel; Strauss, Michael A.; Huff, Eric M.; Bahcall, Neta A.

2014-11-01

326

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

327

Photogrammetric co-registration and photometric analysis of HRSC Phobos images  

NASA Astrophysics Data System (ADS)

HRSC images from Mars Express Phobos flybys are used to study the photometric character of the surface of the Martian satellite. This investigation involves measuring of surface reflectance and illumination angles for estimates of a phase curve, and fitting of theoretic photometric functions. As results we obtain information on multispectral and physical properties of the Phobos surface as well as photometrically corrected geomorphological and albedo maps.

Pasewaldt, A.; Willner, K.; Oberst, J.; Scholten, F.; Wählisch, M.; Matz, K.-D.; Roatsch, T.; Hoffmann, H.; Grechishev, A.; Patsyn, V.

2012-09-01

328

HST-NICMOS Color Transformations and Photometric Calibrations  

E-print Network

This paper presents color transformations for HST NICMOS camera 2 observations to the ground-based CIT/CTIO photometric system, using observations of nineteen moderately bright, red stars in Baade's window in the color range 0.7 < (J-K) < 1.6. We estimate an extension of the transformation to 0.4 < (J-K) < 3.0 with five standards observed by STScI. Convolving near-IR spectra taken above the atmosphere with different filter transmission profiles, we simulate both NICMOS and ground-based photometry, obtaining results which are consistent with our transformation and its extension.

Andrew W. Stephens; Jay A. Frogel; Sergio Ortolani; Roger Davies; Pascale Jablonka; Alvio Renzini; R. Michael Rich

1999-09-01

329

Photometric analysis of RR Lyrae stars. II - T Sextantis  

NASA Astrophysics Data System (ADS)

Observational information including photometric data on T Sex are examined to characterize the periodicity and amplitude variations of the object. T Sex is shown to be multiperiodic with three periods of pulsation 3.080537, 8.167766, and 13.333605 c/d with amplitudes of 0.235, 0.028, and 0.015 mag. The investigation verifies the variation of T Sex's principal period and is used to explain the variation in the amplitude of the day vs night light curves.

Hobart, M. A.; Pena, J. H.; Peniche, R.

1991-10-01

330

Photometric and spectral properties of some T Tauri stars  

NASA Technical Reports Server (NTRS)

Photometric and spectroscopic data have been obtained for selected T Tauri members of the Taurus-Aurigae cloud and the Orion complex. A correlation between the intensity ratio of calcium and hydrogen emission lines and the infrared excess at 3.5 microns is found for these stars, which indicates a causal relationship between 'chromospheric activity' and emission processes in the circumstellar shells. It is argued that a comparison with properties of well-studied novae could lead to a better understanding of the physical structure of T Tauri stars.

Warner, J. W.; Hubbard, R. P.; Gallagher, J. S.

1978-01-01

331

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

332

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.

333

Inference of total ozone from photometric measurements of sky radiation.  

NASA Technical Reports Server (NTRS)

Ground-based photometric measurements of spectral sky radiation have been made using a simple filter instrument. Sky radiation intensities measured in the solar vertical at 3200 and 3600 A are compared to infer total ozone. A model of a multiple scattering Rayleigh atmosphere serves as a primary reduction parameter. Spectral measurements of all-sky radiance distribution are used to study the effects of haze and clouds on the inference of total ozone. The brightness distribution of clear and overcast sky in ultraviolet is also described.

Ghazi, A.

1973-01-01

334

Periodic photometric variability of the brown dwarf Kelu-1  

Microsoft Academic Search

We have detected a strong periodicity of 1.80+\\/-0.05 hours in photometric\\u000aobservations of the brown dwarf Kelu-1. The peak-to-peak amplitude of the\\u000avariation is ~1.1% (11.9+\\/-0.8 mmag) in a 41nm wide filter centred on 857nm and\\u000aincluding the dust\\/temperature sensitive TiO & CrH bands. We have identified\\u000atwo plausible causes of variability: surface features rotating into- and\\u000aout-of-view and so

F. J. Clarke; C. G. Tinney; K. R. Covey

2002-01-01

335

Preliminary Result of Photometric Study of V899 Her  

NASA Astrophysics Data System (ADS)

We present new CCD photometric observation of V899 Herculis system which obtained in May-June 2010 at Bosscha Observatory ITB, Lembang Indonesia, using the 20.3 cm(f/10.0) Schmidt-Cassegrain GAO-ITB RTS telescope equipped with ST8 CCD camera. We secure 1 time of primary minimum. We employed Cubic Fit method tep{bre1973} to make minimum timing and define the primary minima. Discussion on the nature of V899 Her based on new O-C diagram analysis will be presented.

Suherli, J.; Malasan, H. L.

2011-12-01

336

UBVRI observations of stars in the Guide Star Photometric Catalogue.  

NASA Astrophysics Data System (ADS)

Photoelectric UBVRI observations are given for 336 stars brighter than 11.5 mag from the Hubble Space Telescope Guide Star Photometric Catalogue (GSPC). Apart from a declination-dependent effect in the V magnitudes there are no systematic differences between GSPC and SAAO data which are significantly greater than differences between the Landolt and E-region standard systems. The declination effect might be due to the occurrence of unusually high atmospheric extinction coefficients at CTIO following the eruption of the Mexican volcano, El Chichon.

Kilkenny, D.; Laing, J. D.

337

A photometric study of (2060) Chiron and its coma  

NASA Astrophysics Data System (ADS)

A photometric investigation of the coma around (2060) Chiron was carried out using 29 CCD frames in the Johnson B and V bands. The coma is found to be more extensive than previous studies have shown; it can be followed to a mean distance of 30 arcsec from the center. The morphology is not found to change during the observing period, and there are no jetlike features in the elliptically shaped coma. The radial dependence of the surface flux indicates a rather deep density gradient. The mean coma color is unusually blue, and there is an indication that it reddens somewhat outwards.

West, R. M.

1991-01-01

338

Theoretical considerations and a simple method for measuring alkalinity and acidity in low-pH waters by gran titration  

USGS Publications Warehouse

Titrations for alkalinity and acidity using the technique described by Gran (1952, Determination of the equivalence point in potentiometric titrations, Part II: The Analyst, v. 77, p. 661-671) have been employed in the analysis of low-pH natural waters. This report includes a synopsis of the theory and calculations associated with Gran's technique and presents a simple and inexpensive method for performing alkalinity and acidity determinations. However, potential sources of error introduced by the chemical character of some waters may limit the utility of Gran's technique. Therefore, the cost- and time-efficient method for performing alkalinity and acidity determinations described in this report is useful for exploring the suitability of Gran's technique in studies of water chemistry.

Barringer, J.L.; Johnsson, P.A.

1996-01-01

339

Combination of isothermal titration calorimetry and time-resolved luminescence for high affinity antibody-ligand interaction thermodynamics and kinetics  

PubMed Central

For experiments using synthetic ligands as probes for biological experiments, it is useful to determine the specificity and affinity of the ligands for their receptors. As ligands with higher affinities are developed (KA >108 M?1; KD <10?8 M), a new challenge arises: to measure these values accurately. Isothermal titration calorimetry measures heat produced or consumed during ligand binding, and also provides the equilibrium binding constant. However, as normally practiced, its range is limited. Displacement titration, where a competing weaker ligand is used to lower the apparent affinity of the stronger ligand, can be used to determine the binding affinity as well as the complete thermodynamic data for ligand-antibody complexes with very high affinity. These equilibrium data have been combined with kinetic measurements to yield the rate constants as well. We describe this methodology, using as an example antibody 2D12.5, which captures yttrium S-2-(4-aminobenzyl)-1, 4, 7, 10-tetraazacyclododecanetetraacetate. PMID:21964396

Aweda, Tolulope A.; Meares, Claude F.

2011-01-01

340

Low-dose, titratable interferon alfa in decompensated liver disease caused by chronic infection with hepatitis B virus  

Microsoft Academic Search

Background & Aims: Interferon therapy has been associated with a number of severe side effects when administered to patients with decompensated cirrhosis caused by chronic hepatitis B. The safety and potential efficacy of a low-dose, titratable regimen of interferon alfa-2b in patients with decompensated liver disease caused by chronic hepatitis B virus infection were studied. Methods: Twenty-six patients were treated

Robert Perrillo; Carlo Tamburro; Fredric Regenstein; Luis Balart; Henry Bodenheimer; Marcelo Silva; Eugene Schiff; Carol Bodicky; Barbara Miller; Cheryl Denham; Carmel Brodeur; Kathy Roach; Janice Albrecht

1995-01-01

341

Prediction of coagulation properties, titratable acidity, and pH of bovine milk using mid-infrared spectroscopy  

Microsoft Academic Search

This study investigated the potential application of mid-infrared spectroscopy (MIR 4,000-900 cm ?1 ) for the determination of milk coagulation properties (MCP), titratable acidity (TA), and pH in Brown Swiss milk samples (n = 1,064). Because MCP directly influence the efficiency of the cheese-making process, there is strong industrial interest in developing a rapid method for their assessment. Currently, the

M. De Marchi; C. C. Fagan; C. P. O’Donnell; A. Cecchinato; R. Dal Zotto; M. Cassandro; M. Penasa; G. Bittante

2009-01-01

342

In vivo titration of white spot syndrome virus (WSSV) in specific pathogen-free Litopenaeus vannamei by intramuscular and oral routes.  

PubMed

White spot syndrome virus (WSSV) is a devastating pathogen in shrimp aquaculture. Standardized challenge procedures using a known amount of infectious virus would assist in evaluating strategies to reduce its impact. In this study, the shrimp infectious dose 50% endpoint (SID50 ml(-1)) of a Thai isolate of WSSV was determined by intramuscular inoculation (i.m.) in 60 and 135 d old specific pathogen-free (SPF) Litopenaeus vannamei using indirect immunofluorescence (IIF) and 1-step polymerase chain reaction (PCR). Also, the lethal dose 50% endpoint (LD50 ml(-1)) was determined from the proportion of dead shrimp. The median virus infection titers in 60 and 135 d old juveniles were 10(6.8) and 10(6.5) SID50 ml(-1), respectively. These titers were not significantly different (p > or = 0.05). The titration of the WSSV stock by oral intubation in 80 d old juveniles resulted in approximately 10-fold reduction in virus titer compared to i.m. inoculation. This lower titer is probably the result of physical and chemical barriers in the digestive tract of shrimp that hinder WSSV infectivity. The titers determined by infection were identical to the titers determined by mortality in all experiments using both i.m. and oral routes at 120 h post inoculation (hpi), indicating that every infected shrimp died. The determination of WSSV titers for dilutions administered by i.m. and oral routes constitutes the first step towards the standardization of challenge procedures to evaluate strategies to reduce WSSV infection. PMID:16231643

Escobedo-Bonilla, C M; Wille, M; Sanz, V Alday; Sorgeloos, P; Pensaert, M B; Nauwynck, H J

2005-09-01

343

Heat or insulation: behavioral titration of mouse preference for warmth or access to a nest.  

PubMed

In laboratories, mice are housed at 20-24°C, which is below their lower critical temperature (?30°C). This increased thermal stress has the potential to alter scientific outcomes. Nesting material should allow for improved behavioral thermoregulation and thus alleviate this thermal stress. Nesting behavior should change with temperature and material, and the choice between nesting or thermotaxis (movement in response to temperature) should also depend on the balance of these factors, such that mice titrate nesting material against temperature. Naïve CD-1, BALB/c, and C57BL/6 mice (36 male and 36 female/strain in groups of 3) were housed in a set of 2 connected cages, each maintained at a different temperature using a water bath. One cage in each set was 20°C (Nesting cage; NC) while the other was one of 6 temperatures (Temperature cage; TC: 20, 23, 26, 29, 32, or 35°C). The NC contained one of 6 nesting provisions (0, 2, 4, 6, 8, or 10g), changed daily. Food intake and nest scores were measured in both cages. As the difference in temperature between paired cages increased, feed consumption in NC increased. Nesting provision altered differences in nest scores between the 2 paired temperatures. Nest scores in NC increased with increasing provision. In addition, temperature pairings altered the difference in nest scores with the smallest difference between locations at 26°C and 29°C. Mice transferred material from NC to TC but the likelihood of transfer decreased with increasing provision. Overall, mice of different strains and sexes prefer temperatures between 26-29°C and the shift from thermotaxis to nest building is seen between 6 and 10 g of material. Our results suggest that under normal laboratory temperatures, mice should be provided with no less than 6 grams of nesting material, but up to 10 grams may be needed to alleviate thermal distress under typical temperatures. PMID:22479340

Gaskill, Brianna N; Gordon, Christopher J; Pajor, Edmond A; Lucas, Jeffrey R; Davis, Jerry K; Garner, Joseph P

2012-01-01

344

Thermodynamics of Interaction between Some Cellulose Ethers and SDS by Titration Microcalorimetry.  

PubMed

The interaction between certain nonionic cellulose ethers (ethyl hydroxyethyl cellulose and hydroxypropyl methyl cellulose) and sodium dodecyl sulphate (SDS) has been investigated using isothermal titration microcalorimetry at temperatures between 25-50 degrees C. The observed heat flow curves have been interpreted in terms of a plausible mechanism of the interaction of the substituent groups with SDS monomers and clusters. The data have been related to changes occuring in the system at the macro- and microscopic levels with the addition of surfactants and with temperature. The process consists predominantly of polymer-surfactant interactions initially and surfactant-surfactant interactions at the later stages. A phenomenological model of the cooperative interaction (adsorption) process has been derived, and earlier published equilibrium binding data have been used to recover binding constants and Gibbs energy changes for this process. The adsorption enthalpies and entropies have been recovered along with the heat capacity change. The enthalpic cost of confining the nonpolar regions of the polymers in surfactant clusters is high, but the entropy gain from release of hydration shell water molecules as well as increased freedom of movement of these nonpolar regions in the clusters gives the process a strong entropic driving force. The process is entropy-driven initially and converts to being both enthalpy and entropy-driven at high SDS concentrations. An enthalpy-entropy compensation behavior is seen. Strongly negative heat capacity changes have been obtained resulting from the transfer of nonpolar groups from aqueous into nonpolar environments, as well as a reduction of conformational domains that the chains can populate. Changes in these two components cause the heat capacity change to become less negative at the higher binding levels. The system can be classified as exhibiting nonclassical hydrophobic binding at the later stages of binding. Copyright 1999 Academic Press. PMID:10191016

Singh; Nilsson

1999-05-01

345

A Bovine Model of Respiratory Chlamydia psittaci Infection: Challenge Dose Titration  

PubMed Central

This study aimed to establish and evaluate a bovine respiratory model of experimentally induced acute C. psittaci infection. Calves are natural hosts and pathogenesis may resemble the situation in humans. Intrabronchial inoculation of C. psittaci strain DC15 was performed in calves aged 2–3 months via bronchoscope at four different challenge doses from 106 to 109 inclusion-forming units (ifu) per animal. Control groups received either UV-inactivated C. psittaci or cell culture medium. While 106 ifu/calf resulted in a mild respiratory infection only, the doses of 107 and 108 induced fever, tachypnea, dry cough, and tachycardia that became apparent 2–3 days post inoculation (dpi) and lasted for about one week. In calves exposed to 109 ifu C. psittaci, the respiratory disease was accompanied by severe systemic illness (apathy, tremor, markedly reduced appetite). At the time point of most pronounced clinical signs (3 dpi) the extent of lung lesions was below 10% of pulmonary tissue in calves inoculated with 106 and 107 ifu, about 15% in calves inoculated with 108 and more than 30% in calves inoculated with 109 ifu C. psittaci. Beside clinical signs and pathologic lesions, the bacterial load of lung tissue and markers of pulmonary inflammation (i.e., cell counts, concentration of proteins and eicosanoids in broncho-alveolar lavage fluid) were positively associated with ifu of viable C. psittaci. While any effect of endotoxin has been ruled out, all effects could be attributed to infection by the replicating bacteria. In conclusion, the calf represents a suitable model of respiratory chlamydial infection. Dose titration revealed that both clinically latent and clinically manifest infection can be reproduced experimentally by either 106 or 108 ifu/calf of C. psittaci DC15 while doses above 108 ifu C. psittaci cannot be recommended for further studies for ethical reasons. This defined model of different clinical expressions of chlamydial infection allows studying host-pathogen interactions. PMID:22299031

Reinhold, Petra; Ostermann, Carola; Liebler-Tenorio, Elisabeth; Berndt, Angela; Vogel, Anette; Lambertz, Jacqueline; Rothe, Michael; Rüttger, Anke; Schubert, Evelyn; Sachse, Konrad

2012-01-01

346

Energetics of carbohydrate binding to Momordica charantia (bitter gourd) lectin: an isothermal titration calorimetric study.  

PubMed

Physico-chemical and carbohydrate binding studies have been carried out on the Momordica charantia (bitter gourd) seed lectin (MCL). The lectin activity is maximal in the pH range 7.4-11.0, but decreases steeply below pH 7.0. The lectin activity is mostly unaffected in the temperature range 4-50 degrees C, but a sharp decrease is seen between 50 and 60 degrees C, which could be correlated to changes in the structure of the protein as seen by circular dichroism and fluorescence spectroscopy. Isothermal titration calorimetric studies show that the tetrameric MCL binds two sugar molecules and the binding constants (Kb), determined at 288.15 K, for various saccharides were found to vary between 7.3 x 10(3) and 1.52 x 10(4)M(-1). The binding reactions for all the saccharides investigated were essentially enthalpy driven, with the binding enthalpies (DeltaHb) at 288.15 K being in the range of -50.99 and -43.39 kJ mol(-1), whereas the contribution to the binding reaction from the entropy of binding was negative, with values of binding entropy (DeltaSb) ranging between -99.2 and -72.0 J mol(-1)K(-1) at 288.15 K. Changes in heat capacity (DeltaCp) for the binding of disaccharides, lactose and lactulose, were significantly larger in magnitude than those obtained for the monosaccharides, methyl-beta-D-galactopyranoside, and methyl-alpha-D-galactopyranoside, and could be correlated reasonably well with the surface areas of these ligands. Enthalpy-entropy compensation was observed for all the sugars studied, suggesting that water structure plays an important role in the overall binding reaction. CD spectroscopy indicates that carbohydrate binding does not lead to significant changes in the secondary and tertiary structures of MCL, suggesting that the carbohydrate binding sites on this lectin are mostly preformed. PMID:15820223

Sultan, Nabil Ali Mohammed; Swamy, Musti J

2005-05-01

347

Microcalorimetric and potentiometric titration studies on the adsorption of copper by extracellular polymeric substances (EPS), minerals and their composites.  

PubMed

Equilibrium adsorption experiments, isothermal titration calorimetry and potentiometric titration techniques were employed to investigate the adsorption of Cu(II) by extracellular polymeric substances (EPS) extracted from Pseudomonas putida X4, minerals (montmorillonite and goethite) and their composites. Compared with predicted values of Cu(II) adsorption on composites, the measured values of Cu(II) on EPS-montmorillonite composite increased, however, those on EPS-goethite composite decreased. Potentiometric titration results also showed that more surface sites were observed on EPS-montmorillonite composite and less reactive sites were found on EPS-goethite composite. The adsorption of Cu(II) on EPS molecules and their composites with minerals was an endothermic reaction, while that on minerals was exothermic. The positive values of enthalpy change (Delta H) and entropy change (DeltaS) for Cu(II) adsorption on EPS and mineral-EPS composites indicated that Cu(II) mainly interacts with carboxyl and phosphoryl groups as inner-sphere complexes on EPS molecules and their composites with minerals. PMID:20227874

Fang, Linchuan; Huang, Qiaoyun; Wei, Xing; Liang, Wei; Rong, Xinming; Chen, Wenli; Cai, Peng

2010-08-01

348

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

349

Testing the Halo Model Against the SDSS Photometric Survey  

E-print Network

We present halo model predictions for the expected angular clustering and associated errors from the completed Sloan Digital Sky Survey (SDSS) photometric galaxy sample. These results are used to constrain halo model parameters under the assumption of a fixed LCDM cosmology using standard Fisher matrix techniques. Given the ability of the five-color SDSS photometry to separate galaxies into sub-populations by intrinsic color, we also use extensions of the standard halo model formalism to calculate the expected clustering of red and blue galaxy sub-populations as a further test of the galaxy evolution included in the semi-analytic methods for populating dark matter halos with galaxies. The extremely small sample variance and Poisson errors from the completed SDSS survey should result in very impressive constraints (~1-10%) on the halo model parameters for a simple magnitude-limited sample and should provide an extremely useful check on the behavior of current and future N-body simulations and semi-analytic techniques. We also show that similar constraints are possible using a narrow selection function, as would be possible using photometric redshifts, without making linear assumptions regarding the evolution of the underlying power spectra. In both cases, we explore the effects of uncertainty in the selection function on the resulting constraints and the degeneracies between various combinations of parameters.

Ryan Scranton

2002-05-30

350

Comparison of Solar Photometric Data from Two Telescopes  

NASA Astrophysics Data System (ADS)

Sunspot areas from two photometric telescopes have been compared. The two telescopes are the Precision Solar Photometric Telescope (PSPT) operated on Mauna Loa by the High Altitude Observatory (HAO) and the Cartesian Full Disk Telescope 2 (CFDT2) operated at the San Fernando Observatory (SFO). The PSPT images originally 2048 x 2048 have been binned by two to agreee more closely with those from CFDT2. The binned PSPT pixels are 2" x 2" and the CFDT2 pixels are 2.5" x 2.5". A preliminary analysis shows that sunspot areas from the two are highly correlated although only seven image pairs have been correlated. Comparing the red PSPT spot areas with the red CFDT2 spot areas gives an r2 of 0.9947 and a scale factor of 0.909 +/- 0.03 where the scale factor implies the red areas are slightly too small. For CFDT2 blue images versus the red PSPT the r2 is 0.9895 with a scale factor of 1.06 +/- 0.05 implying that the blue areas are slightly too large. Results from other wavelengths and from an expanded data set will be presented and discussed. This research was partially supported by grants from NSF, NASA and a visiting scientist grant from HAO.

Chapman, G. A.; Walton, S. R.; deToma, G.; White, O. R.

2001-12-01

351

A Photometrically and Morphologically Variable Infrared Nebula in L483  

E-print Network

We present narrow and broad K-band observations of the Class 0/I source IRAS 18148-0440 that span 17 years. The infrared nebula associated with this protostar in the L483 dark cloud is both morphologically and photometrically variable on a time scale of only a few months. This nebula appears to be an infrared analogue to other well-known optically visible variable nebulae associated with young stars, such as Hubble's Variable Nebula. Along with Cepheus A, this is one of the first large variable nebulae to be found that is only visible in the infrared. The variability of this nebula is most likely due to changing illumination of the cloud rather than any motion of the structure in the nebula. Both morphological and photometric changes are observed on a time scale only a few times longer than the light crossing time of the nebula, suggesting very rapid intrinsic changes in the illumination of the nebula. Our narrow-band observations also found that H_2 knots are found nearly twice as far to the east of the source as to its west, and that H_2 emission extends farther east of the source than the previously known CO outflow.

Michael Connelley; Klaus Hodapp; Gary Fuller

2008-11-07

352

USING COLORS TO IMPROVE PHOTOMETRIC METALLICITY ESTIMATES FOR GALAXIES  

SciTech Connect

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.; Soderberg, A. M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Levesque, E. M., E-mail: nsanders@cfa.harvard.edu [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, 389-UCB, Boulder, CO 80309 (United States)

2013-10-01

353

Photometric study of HD 155555C in the ? Pictoris Association  

NASA Astrophysics Data System (ADS)

We are carrying out a series of photometric monitoring to measure the rotation periods of members in the young ? Pictoris Association, as part of the RACE-OC project (Rotation and ACtivity Evolution in Open Clusters). In this paper, we present the results for HD 155555C which is believed to be physically associated to the spectroscopic binary V824 Ara (HD 155555) and thus constituting a triple system. We collected B, V, and R-band photometric data timeseries and discovered from periodogram analysis the rotation period P = 4.43 d. Combined with stellar radius and projected rotational velocity, we find this star almost equator-on with an inclination i ? 90 ° . The rotational properties of HD 155555C fit well into the period distribution of other ? Pic members, giving further support to the suggested membership to the association and to its physical association to V824 Ara. A comparison with pre-main-sequence isochrones from various models allows us to estimate an age of 20 ± 15 Myr for this triple system.

Messina, Sergio; Millward, Mervyn; Bradstreet, David H.

2015-05-01

354

Quantifying photometric observing conditions on Paranal using an IR camera  

NASA Astrophysics Data System (ADS)

A Low Humidity and Temperature Profiling (LHATPRO) microwave radiometer, manufactured by Radiometer Physics GmbH (RPG), is used to monitor sky conditions over ESO's Paranal observatory in support of VLT science operations. In addition to measuring precipitable water vapour (PWV) the instrument also contains an IR camera measuring sky brightness temperature at 10.5 ?m. Due to its extended operating range down to -100 °C it is capable of detecting very cold and very thin, even sub-visual, cirrus clouds. We present a set of instrument flux calibration values as compared with a detrended fluctuation analysis (DFA) of the IR camera zenith-looking sky brightness data measured above Paranal taken over the past two years. We show that it is possible to quantify photometric observing conditions and that the method is highly sensitive to the presence of even very thin clouds but robust against variations of sky brightness caused by effects other than clouds such as variations of precipitable water vapour. Hence it can be used to determine photometric conditions for science operations. About 60 % of nights are free of clouds on Paranal. More work will be required to classify the clouds using this technique. For the future this approach might become part of VLT science operations for evaluating nightly sky conditions.

Kerber, Florian; Querel, Richard R.; Hanuschik, Reinhard

2014-08-01

355

Photometric Investigation of the Eclipsing Binary Star BX Dra  

NASA Astrophysics Data System (ADS)

We present here the photometric light curve analysis of the eclipsing binary star BX Dra. The eclipsing binary star BX Dra was observed by Jerry Gunn and Brian Hakes using the Jubilee observatory near Peoria, Illinois and the Meade LX 2000 Hanna City Robotic Telescope and a CCD photometer at Hanna City, Illinois. The data spans over nine nights in 1997 in B and V band-pass filters. We obtained a revised orbital period of 0.579097 days from 15 eclipsing minima. The published spectral classification is A3. The 1993 version of the Wislon-devinney model gave the photometric solutions. The adopted solution indicates that BX Dra is W UMa type contact binary. The mass ratio, q = (m2 /m1, where star 1 eclipses at the primary minimum) = 0.26 suggest that BX Dra is a W UMA system with A-type configuration. Generally contact systems of spectral type A3 have periods ranging from 0.4 to 0.6 days. BX Dra has considerably longer periods and thus appears to be an evolved contact with case B mass transfer. We recommend spectroscopic study of this system.

Goderya, Shaukat N.; Sykes, T.

2006-12-01

356

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.

357

Sorption modelling on illite Part I: Titration measurements and the sorption of Ni, Co, Eu and Sn  

NASA Astrophysics Data System (ADS)

In this study the physico-chemical, titration and sorption characteristics of Na-illite du Puy (Na-illite) have been measured and modelled. Samples of illite, collected in the region of le Puy-en-Velay, France, were purified and conditioned to the Na-form and physico-chemically characterised. Potentiometric titrations on suspensions of the Na-illite were carried out using a batch backtitration technique in 0.01, 0.1 and 0.5 M NaClO 4 background electrolytes from pH˜3 to ˜11.5 in an inert atmosphere glove box. The supernatant solutions from each titration experiment in each series were analysed for K, Mg, Ca, Sr, Si, Al, Fe and Mn. The titration data were modelled in terms of the protolysis of two amphoteric edge sites ( tbnd S W1OH and tbnd S W2OH) without an electrostatic term. Sorption edges (solid/liquid distribution ratios versus pH at trace sorbate concentrations and constant ionic strength) were determined for the transitions metals Ni(II) and Co(II), the lanthanide Eu(III), and the heavy metal Sn(IV) on Na-illite with NaClO 4 as the background electrolyte under anoxic conditions (CO 2 ? 2 ppm, O 2 ? 2 ppm). The study thus encompasses a broad range of metals with different thermodynamic characteristics and with valence states ranging from II to IV. The results from the modelling of the titration data, in combination with a non electrostatic surface complexation and cation exchange sorption model were applied to quantitatively describe the uptake characteristics of the metals listed above on Na-illite. Since sorption edges were measured at trace concentrations, metal uptake was modelled as occurring on strong type sites ( tbnd S SOH) only. This sorption model, the two site protolysis non electrostatic surface complexation and cation exchange model (2SPNE SC/CE model) had been previously developed and used to describe metal uptake on montmorillonite.

Bradbury, M. H.; Baeyens, B.

2009-02-01

358

An Enzyme Coupling Procedure for the Determination of Lipoprotein Lipase Activity  

Microsoft Academic Search

A novel, sensitive enzyme coupling procedure is described for the quantitative determination of both purified bovine milk lipoprotein lipase (LPL) and human post-heparin plasma lipolytic activity (PHLA). The primary assay is carried out with the aid of a triolein emulsion optimized as regards NaCl, bile salt and C II apolipoprotein concentration. The secondary reaction consists of the photometric measurement of

P. Victoratos; S. Asvesta; P. L. Arzoglou

1990-01-01

359

Procedural knowledge  

NASA Technical Reports Server (NTRS)

Much of commonsense knowledge about the real world is in the form of procedures or sequences of actions for achieving particular goals. In this paper, a formalism is presented for representing such knowledge using the notion of process. A declarative semantics for the representation is given, which allows a user to state facts about the effects of doing things in the problem domain of interest. An operational semantics is also provided, which shows how this knowledge can be used to achieve particular goals or to form intentions regarding their achievement. Given both semantics, the formalism additionally serves as an executable specification language suitable for constructing complex systems. A system based on this formalism is described, and examples involving control of an autonomous robot and fault diagnosis for NASA's Space Shuttle are provided.

Georgeff, Michael P.; Lansky, Amy L.

1986-01-01

360

A protocol analysis of the influence of technology on students' actions, verbal commentary, and thought processes during the performance of acid-base titrations  

Microsoft Academic Search

We investigated students' initial and final understanding of acid-base concepts and their concurrent thought processes and actions during the process of acid-base titrations. Here we report students' actions and thought processes while titrating. Different levels of information were presented by three technologies: chemical indicators, pH meters, and microcomputer-based laboratories. We speculated that the level of information would influence students' actions

Mary B. Nakhleh; Joseph S. Krajcik

1993-01-01

361

A bovine model of respiratory Chlamydia psittaci infection: challenge dose titration.  

PubMed

This study aimed to establish and evaluate a bovine respiratory model of experimentally induced acute C. psittaci infection. Calves are natural hosts and pathogenesis may resemble the situation in humans. Intrabronchial inoculation of C. psittaci strain DC15 was performed in calves aged 2-3 months via bronchoscope at four different challenge doses from 10(6) to 10(9) inclusion-forming units (ifu) per animal. Control groups received either UV-inactivated C. psittaci or cell culture medium. While 10(6) ifu/calf resulted in a mild respiratory infection only, the doses of 10(7) and 10(8) induced fever, tachypnea, dry cough, and tachycardia that became apparent 2-3 days post inoculation (dpi) and lasted for about one week. In calves exposed to 10(9) ifu C. psittaci, the respiratory disease was accompanied by severe systemic illness (apathy, tremor, markedly reduced appetite). At the time point of most pronounced clinical signs (3 dpi) the extent of lung lesions was below 10% of pulmonary tissue in calves inoculated with 10(6) and 10(7) ifu, about 15% in calves inoculated with 10(8) and more than 30% in calves inoculated with 10(9) ifu C. psittaci. Beside clinical signs and pathologic lesions, the bacterial load of lung tissue and markers of pulmonary inflammation (i.e., cell counts, concentration of proteins and eicosanoids in broncho-alveolar lavage fluid) were positively associated with ifu of viable C. psittaci. While any effect of endotoxin has been ruled out, all effects could be attributed to infection by the replicating bacteria. In conclusion, the calf represents a suitable model of respiratory chlamydial infection. Dose titration revealed that both clinically latent and clinically manifest infection can be reproduced experimentally by either 10(6) or 10(8) ifu/calf of C. psittaci DC15 while doses above 10(8) ifu C. psittaci cannot be recommended for further studies for ethical reasons. This defined model of different clinical expressions of chlamydial infection allows studying host-pathogen interactions. PMID:22299031

Reinhold, Petra; Ostermann, Carola; Liebler-Tenorio, Elisabeth; Berndt, Angela; Vogel, Anette; Lambertz, Jacqueline; Rothe, Michael; Rüttger, Anke; Schubert, Evelyn; Sachse, Konrad

2012-01-01

362

Can a Tool That Automates Insulin Titration Be a Key to Diabetes Management?  

PubMed Central

Abstract Background Most patients who use insulin do not achieve optimal glycemic control and become susceptible to complications. Numerous clinical trials have shown that frequent insulin dosage titration is imperative to achieve glycemic control. Unfortunately, implementation of such a paradigm is often impractical. We hypothesized that the Diabetes Insulin Guidance System (DIGS™) (Hygieia, Inc., Ann Arbor, MI) software, which automatically advises patients on adjustment of insulin dosage, would provide safe and effective weekly insulin dosage adjustments. Subjects and Methods In a feasibility study we enrolled patients with type 1 and type 2 diabetes, treated with a variety of insulin regimens and having suboptimal glycemic control. The 12-week intervention period followed a 4-week baseline run-in period. During the intervention, DIGS processed patients' glucose readings and provided insulin dosage adjustments on a weekly basis. If approved by the study team, the adjusted insulin dosage was communicated to the patients. Insulin formulations were not changed during the study. The primary outcome was the fraction of DIGS dosage adjustments approved by the study team, and the secondary outcome was improved glycemic control. Results Forty-six patients were recruited, and eight withdrew. The DIGS software recommended 1,734 insulin dosage adjustments, of which 1,731 (99.83%) were approved. During the run-in period the weekly average glucose was stable at 174.2±36.7?mg/dL (9.7±2.0?mmol/L). During the following 12 weeks, DIGS dosage adjustments resulted in progressive improvement in average glucose to 163.3±35.1?mg/dL (9.1±1.9?mmol/L) (P<0.03). Mean glycosylated hemoglobin decreased from 8.4±0.8% to 7.9±0.9% (P<0.05). Concomitantly, the frequency of hypoglycemia decreased by 25.2%. Conclusions The DIGS software provided patients with safe and effective weekly insulin dosage adjustments. Widespread implementation of DIGS may improve the outcome and reduce the cost of implementing effective insulin therapy. PMID:22568777

Bergenstal, Richard M.; Bashan, Eran; McShane, Margaret; Johnson, Mary

2012-01-01

363

Determining Grasp Configurations using Photometric Stereo and the PRISM Binocular Stereo System  

Microsoft Academic Search

This paper describes a system which locates and grasps parts from a pile. The system uses photometric stereo and binocu lar stereo as vision input tools. Photometric stereo is used to make surface orientation measurements. With this informa tion the camera field is segmented into isolated regions of a continuous smooth surface. One of these regions is then selected as

Katsushi Ikeuchi; H. Keith Nishihara; Berthold K. P. Horn; Patrick Sobalvarro; Shigemi Nagata

1986-01-01

364

PREDICTING THE YIELDS OF PHOTOMETRIC SURVEYS FOR TRANSITING EXTRASOLAR PLANETS Thomas G. Beatty1  

E-print Network

estimates of the giant planet frequency, account for the number and distribution of main-sequence starsPREDICTING THE YIELDS OF PHOTOMETRIC SURVEYS FOR TRANSITING EXTRASOLAR PLANETS Thomas G. Beatty1 for predicting the yield of transiting planets from a photometric survey given the parameters of the survey

Gaudi, B. Scott

365

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

366

Photometric modeling of viscous overstability in Saturn's rings  

NASA Astrophysics Data System (ADS)

The viscous overstability of dense planetary rings offers a plausible mechanism for the generation of observed ~ 150 m radial density variations in the B and the inner A ring of Saturn [1, 12]. Viscous overstability, in the form of spontaneous growth of axisymmetric oscillations, arises naturally in N-body simulations, in the limit of high impact frequency and moderately weak selfgravity [4, 8, 9, 10]. For example, a selfgravitating system of identical particles with internal density ~ half of solid ice, becomes overstable for optical depths ? > 1, forming oscillations on about 100 meter scale. Like self-gravity wakes (with typical ~ 20° trailing pitch angle), overstable oscillations lead to alongitude-dependent brightness of the rings. Due to their axisymmetric nature, the expected longitude of minimum brightness is shifted closer to ring ansae (for small phase angles). Moreover, according to simulations, the axisymmetric oscillations may coexist with the inclined selfgravity wake structures, which can lead to complicated photometric behavior as a function of illumination and viewing geometries, depending on properties of the simulated system. For example, at low viewing elevations, the vertical thickenings associated with the density crests should cast shadows on the nearby ring particles (see Fig. 1 for an example; darker areas are due to shadows, not due to depletion of particles). Though these shadows would be unresolved, they might still affect the integrated brightness at certain geometries. The overstable systems may also exhibit amplitude variations (in km-scales), arising from the mutual beating patterns of the basic sub-km overstable oscillations [3]. Such modulations of oscillation amplitude may lead to associated brightness variations. New results of photometric modeling of viscously overstable dynamical simulations systems are reported, related to the above mentioned topics. The Monte Carlo method of [5] is used, previously applied to modeling of photometric signatures of selfgravity wakes [6, 2], scattering properties of propeller structures [11], and most recently to the interpretation of elevation-angle dependent opposition effect seen in HST data [7]. In particular, the possible observable signatures of amplitude modulations and vertical splashing are explored.

Salo, H.; Schmidt, J.

2011-10-01

367

A practical means for calibrating an LED-based photometric stereo system  

NASA Astrophysics Data System (ADS)

Conventional Photometric Stereo (PS) techniques are usually based on the assumption that the light sources are assumed sufficiently far from the object that all incoming light can be modeled using parallel rays. Meanwhile, for near-field lighting conditions the light sources are close to the object so the parallel ray model cannot be used. To determine the surface normal for each point on the object more accurately, the incoming light direction should be calculated individually for each point. In this work, based on a simple PS setup consisting of LED lamps and one camera, we present a practical method for calibrating lighting directions. First, an optical model of an LED was introduced in the calibration procedure to represent the surface irradiance and image irradiance more accurately. A reference sphere was used for the calibration so that the LED optical axis could be estimated by extracting the specular points from the reference sphere. By introducing the LED emitting model, distance between the LED and the specular point along the optical axis can be calculated. Thus, the incident lighting directions for various image points can be estimated individually. To improve the estimation robustness, a non-linear fitting approach was also applied. Experiments were conducted using objects and the results are compared with traditional methods to demonstrate its feasibility and improvement.

Xie, Limin; Song, Zhan; Jiao, Guohua; Huang, Xinhan; Jia, Kui

2015-01-01

368

The Lick AGN Monitoring Project 2. Photometric Light Curves  

NASA Astrophysics Data System (ADS)

The Lick AGN Monitoring Project (LAMP) targeted 13 nearby Seyfert 1 galaxies with the intent of measuring the masses of their central black holes using reverberation mapping. In conjunction with the spectroscopic monitoring, we obtained broad-band B and V imaging observations on most nights between the months of February and May 2008. The sample of 13 objects was divided between four telescopes: the 30-inch Katzman Automatic Imaging Telescope (KAIT), the 2-meter Multicolor Active Galactic Nuclei Monitoring (MAGNUM) telescope, the Palomar 60-inch telescope, and the 32-inch Tenagra II telescope. In this talk, we will discuss the observational methods, the photometric measurements, the resultant light curves, and the variability characteristics of each object.

Walsh, Jonell; LAMP Collaboration

2009-01-01

369

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

370

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.

2014-08-01

371

Photometric confirmation of the Encke division in Saturn's ring A  

NASA Technical Reports Server (NTRS)

A physical model of the behavior of Saturn's satellite Iapetus passing through the shadow of the rings is discussed. The model is examined via computer simulation to give photometric confirmation of the Encke division in ring A. The actual event was observed with a two-channel sky-chopping photometer. Simultaneous pulse-counter output from the red and blue channels was integrated for 10-ms intervals alternately on the sky and on Iapetus. In the computer simulation a solar limb-darkening coefficient was used in the blue region and Iapetus was considered two limb-darkened hemispheres of radii 800 km with the trailing hemisphere brighter than the preceding hemisphere by a factor of seven.

Reitsema, H. J.

1978-01-01

372

Intrinsic alignments of group and cluster galaxies in photometric surveys  

E-print Network

Intrinsic alignments of galaxies have been shown to contaminate weak gravitational lensing observables on linear scales, r > 10 Mpc/h, but studies of alignments in the non-linear regime have thus far been inconclusive. We present an estimator for extracting the intrinsic alignment signal of galaxies around stacked clusters of galaxies from multiband imaging data. Our estimator removes the contamination caused by galaxies that are gravitationally lensed by the clusters and scattered in redshift space due to photometric redshift uncertainties. It uses posterior probability distributions for the redshifts of the galaxies in the sample and it is easily extended to obtain the weak gravitational lensing signal while removing the intrinsic alignment contamination. We apply this algorithm to groups and clusters of galaxies identified in the Sloan Digital Sky Survey `Stripe 82' coadded imaging data over approximately 150 sq. deg. We find that the intrinsic alignment signal around stacked clusters in the redshift range...

Chisari, Nora Elisa; Strauss, Michael A; Huff, Eric; Bahcall, Neta

2014-01-01

373

Photometric Observations of the ? Carinae 2009.0 Spectroscopic Event  

NASA Astrophysics Data System (ADS)

We have observed ? Carinae over 34 nights between 2009 January 4 and 2009 March 27 covering the estimated timeframe for a predicted spectroscopic event related to a suspected binary system concealed within the homunculus nebula. A photometric minimum feature was confirmed to be periodic and comparison to a previous event indicated that the period to within our error was 2022.6+/-1.0d. Using the E-region standard star system, the apparent V magnitudes determined for the local comparison stars were HD 303308 8.14+/-0.02, HD 93205 7.77+/-0.03, and HD 93162 8.22+/-0.05. The latter star was found to be dimmer than previously reported.

Landes, H.; Fitzgerald, M.

2010-09-01

374

Proposal of photometric reverberation mapping with BOOTES-4  

NASA Astrophysics Data System (ADS)

Reverberation mapping(RM) is a powerful technique to measure the mass of black holes in the active galactic nuclei(AGN). Yet the classical RM programs, which uses spectroscopy to monitor emission lines from the broad line region(BLR), are generally limited only for very supermassive black holes with large 2m-calss telescopes. In recent years, a breakthrough is remarkably achieved with photometric RM technique, which opens the door to efficiently measure the BLR size and host-subtracted AGN luminosity even with small telescopes. Considering the availability of other BOOTES telescopes around the world, we could further consider to propose international collaborations as one of the long-term monitoring programs for small telescopes.

Yi, Wei-Min; Wang, Chuan-Jun; Fan, Yu-Feng; Bai, Jin-Ming; Xin, Yu-Xin; Castro-Tirado, Alberto Javier; Guziy, Sergiy

2014-12-01

375

A Large and Faint Photometric Catalog on the Ecliptic  

NASA Astrophysics Data System (ADS)

A photometric catalog, developed for the calibration of the Deep Ecliptic Survey, is presented. The catalog contains 213,272 unique sources that were measured in V and R filters and transformed to the Johnson-Cousins systems using the Landolt standard catalog. All of the sources lie within 6° of the ecliptic and cover all longitudes except for the densest stellar regions nearest the galactic center. Seventeen percent of the sources in the catalog are derived from three or more nights of observation. The catalog contains sources as faint as R ~19 but the largest fraction fall in the R ~15-16 (V ~16-17) mag range. All magnitude bins down to R = 19 have a significant fraction of objects with uncertainties <=0.1 mag.

Buie, Marc W.; Trilling, David E.; Wasserman, Lawrence H.; Crudo, Richard A.

2011-06-01

376

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

377

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

378

Combining Spectroscopic and Photometric Surveys: Same or different sky?  

E-print Network

This article looks at the combined constraints from a photometric and spectroscopic survey. These surveys will measure cosmology using weak lensing (WL), galaxy cluster- ing, baryon acoustic oscillations (BAO) and redshift space distortions (RSD). We find, contrary to some findings in the recent literature, that overlapping surveys can give important benefits when measuring dark energy. We therefore try to clarify the status of this issue with a full forecast of two stage-IV surveys using a new approach to prop- erly account for covariance between the different probes in the overlapping samples. The benefit of the overlapping survey can be traced back to two factors: additional observables and sample variance cancellation. Both needs to be taken into account and contribute equally when combining 3D power spectrum and 2D correlations for lensing. With an analytic example we also illustrate that for optimal constraints, one should minimize the (Pearson) correlation coefficient between cosmological and nui- sanc...

Eriksen, Martin

2014-01-01

379

GAz: A Genetic Algorithm for Photometric Redshift Estimation  

E-print Network

We present a new approach to the problem of estimating the redshift of galaxies from photometric data. The approach uses a genetic algorithm combined with non-linear regression to model the 2SLAQ LRG data set with SDSS DR7 photometry. The genetic algorithm explores the very large space of high order polynomials while only requiring optimisation of a small number of terms. We find a $\\sigma_{\\text{rms}}=0.0408\\pm 0.0006$ for redshifts in the range $0.4

Hogan, Robert; Seeburn, Navin

2014-01-01

380

Insights Into Galaxy Evolution From Photometric Redshifts Across Many Fields  

NASA Astrophysics Data System (ADS)

I present results from a compiled sample spanning a range of public deep-fields, including the GOODS, COSMOS, UKIDSS-UDS and MUSYC fields. Photometric redshifts for these fields were obtained using a homogenous approach using the GAZELLE photo-z code; stellar masses and star formation rates have been estimated by comparison to GALEV evolutionary synthesis models, spanning a wide range of galaxy evolution scenarios. The derived redshift distributions show generally good agreement with predictions from semi-analytical models, based on simulations of cosmological structure formation. Mass-functions of these fields reveal a population of very massive, yet actively star-forming galaxies, in numbers exceeding predictions of current semi-analytical models and hence hinting at an as yet insufficiently understood formation channel producing this kind of galaxy.

Kotulla, Ralf

2011-01-01

381

Titration of human serum antibodies to Toxoplasma gondii with a simple fluorometric assay.  

PubMed Central

A new technique, FIAX, has been evaluated for the serodiagnosis of toxoplasmosis. It is based on a "dipstick" principle, and a special fluorometer is used to perform the indirect immunofluorescence test. The procedure appears to be simple and rapid and merits consideration as a useful serological test for toxoplasmosis. PMID:344343

Walls, K W; Barnhart, E R

1978-01-01

382

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

383

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

384

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

385

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

386

Ion chromatography of cations using indirect photometric of fluorometric detection  

SciTech Connect

Copper(II) and cerium(III) were compared as mobile phase counter-ions with a strong cation exchange column for indirect photometric chromatography (IPC). Sample ion retention time was found to be dependent upon both counter-ion size and charge, as well as mobile phase ionic strength. Detection limits of all sample ions were found to be highly dependent on the molar absorptivity of the counter-ion at the wavelength of detection. At 254nm, a cerium(III) mobile phase provided detection limits at least 100 times lower than did a copper(II) mobile phase. The detection limit of sodium was about 4 ppb, corresponding to 3.5 pmoles, using a Ce(III) mobile phase. Cerium(III) was used as a mobile phase counter-ion with a strong cation exchange column using indirect fluorescence detection. Separation of the alkali metal ions along with the ammonium ion was achieved with baseline resolution. The detection limit of sodium was 3 ppb, corresponding to 2.6 pmoles. Separation and quantitation of sodium, ammonium, and potassium ions in diluted urine was straightforward. In contrast, using indirect UV detection, interference from the sample matrix was a problem. IPC using a cerium(III) mobile phase was used to determine sodium, potassium, magnesium, and calcium ions in milk and infant formulas. Separation was complete within 17 minutes. No interference from the sample matrix was noted. Good agreement between the IPC results and atomic absorption spectroscopy was found. Several complexes of chromium(III) were studied as mobile phase candidates for indirect photometric chromatography. A complex of tris(bipyridine)chromium(III) possessed the required spectral properties of an IPC counterion, but proved to be somewhat labile in either water or methanol but not acetonitrile.

Sherman, J.H.

1987-01-01

387

The photometric evolution of dissolving star clusters I: First predictions  

E-print Network

We calculated the broad-band photometric evolution of unresolved star clusters, including the preferential loss of low-mass stars due to mass segregation. The stellar mass function of a cluster evolves due to three effects: (a) the evolution of massive stars; (b) early tidal effects reduce the mass function independently of the stellar mass; (c) after mass segregation has completed, tidal effects preferentially remove the lowest-mass stars from the cluster. Results: (1) During the first ~40% of the lifetime of a cluster the cluster simply gets fainter due to the loss of stars by tidal effects. (2) Between ~40 and ~80% of its lifetime the cluster gets bluer due to the loss of low-mass stars. This will result in an underestimate of the age of clusters if standard cluster evolution models are used (0.15 -- 0.5 dex). (3) After ~80% of the total lifetime of a cluster it will rapidly get redder. This is because stars at the low-mass end of the main sequence, which are preferentially lost, are bluer than the AGB stars that dominate the light at long wavelengths, resulting in an age overestimate. (4) Clusters with mass segregation and the preferential loss of low-mass stars evolve along almost the same tracks in colour-colour diagrams as clusters without mass segregation. Therefore it will be difficult to distinguish this effect from that due to the cluster age for unresolved clusters, unless the total lifetime of the clusters can be estimated. (5) The changes in the colour evolution of unresolved clusters due to the preferential loss of low-mass stars will affect the determination of the SFHs. (6) The preferential loss of low-mass stars might explain the presence of old (~13 Gyr) clusters in NGC 4365 which are photometrically disguised as intermediate-age clusters (2 - 5 Gyr). [Abridged

Henny J. G. L. M. Lamers; Peter Anders; Richard de Grijs

2006-01-26

388

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

389

Application of direct-injection detector integrated with the multi-pumping flow system to photometric stop-flow determination of total iron.  

PubMed

A novel direct-injection detector (DID) integrated with multi-pumping flow system (MPFS) for the photometric determination of iron is proposed. Paired emitter-detector diodes have been used as a photometric detection system. The sample and reagent were injected using appropriate solenoid pulse micro-pumps directly into the detection chamber where effective mixing occured. The use of proposed stop-flow detector considerably simplified the analytical procedure. The potassium thiocyanate has been chosen as a chromogenic reagent for photometric Fe(III) detection. The total volume of reagent and sample/standard solutions involved in the detection process was adjusted to the volume of the reaction-detection chamber. Calibration graph was found to be linear in the range up to 10mgL(-1). The detection limit (3s(b)/S) was 0.15mgL(-1). The repeatability (R.S.D.), calculated from 10 analyses of sample containing 5mgL(-1) Fe(III), was 1.5% and the sample throughput 180 determinations per hour. The consumption of sample and reagent was 20?L each with the waste generation at the level of 0.24mL. The applicability of the proposed method to the determination of total iron in groundwater samples has been proved. The analytical parameters are compared to those obtained exploiting the MPFS system with typical configuration containing a confluence point and reaction coil. PMID:22817930

Koronkiewicz, Stanislawa; Kalinowski, Slawomir

2012-07-15

390

Thermodynamics of ion binding to phosphatidic acid bilayers. Titration calorimetry of the heat of dissociation of DMPA.  

PubMed

The heat of dissociation of the second proton of 1,2-dimyristoylphosphatidic acid (DMPA) was studied as a function of temperature using titration calorimetry. The dissociation of the second proton of DMPA was induced by addition of NaOH. From the calorimetric titration experiment, the intrinsic pK0 for the dissociation reaction could be determined by applying the Gouy-Chapman theory. pK0 decreases with temperature from ca. 6.2 at 11 degrees C to 5.4 at 54 degrees C. From the total heat of reaction, the dissociation enthalpy, delta Hdiss, was determined by subtracting the heat of neutralization of water and the heat of dilution of NaOH. In the temperature range between 2 and 23 degrees C, delta Hdiss is endothermic with an average value of ca. 2.5 kcal.mol-1 and shows no clear-cut temperature dependence. In the temperature range between 23 and 52 degrees C, delta Hdiss calculated after subtraction of the heat of neutralization and dilution is not the true dissociation enthalpy but includes contributions from the phase transition enthalpy, delta Htrans, as the pH jump induces a transition from the gel to the liquid-crystalline phase. The delta Cp for the reaction enthalpy observed in this temperature range is positive. Above 53 degrees C, the pH jump induces again only the dissociation of the second proton, and the bilayers stay in the liquid-crystalline phase. In this temperature range, delta Hdiss seems to decrease with temperature. The thermodynamic data from titration calorimetry and differential scanning calorimetry as a function of pH can be combined to construct a complete enthalpy-temperature diagram of DMPA in its two ionization states. PMID:1316155

Blume, A; Tuchtenhagen, J

1992-05-19

391

Control of OSA During Automatic Positive Airway Pressure Titration in a Clinical Case Series: Predictors and Accuracy of Device Download Data  

PubMed Central

Study Objectives: To investigate the factors associated with physiologic control of obstructive sleep apnea (OSA) during automatic positive airway pressure (APAP) titration in a clinical series. To also assess the usefulness of apnea-hypopnea index (AHI) data downloaded from the APAP device (Dev AHI). Design: Retrospective review of a consecutive series of patients with OSA who underwent APAP titration (Autoset Spirit, ResMed, Bella Vista, New South Wales, Australia ) with simultaneous polysomnographic (PSG) monitoring in the sleep laboratory. Setting: Tertiary sleep clinic. Participants: There were 190 consecutive patients with OSA referred for APAP titration. Measurements and Results: There were 58% of patients who achieved optimal or good control of OSA (titration PSG AHI < 10, or at least 50% reduction in AHI if diagnostic AHI < 15/hr) during APAP titration. The independent predictors of titration PSG AHI were a history of cardiac disease and elevated central apnea and arousal indices during the diagnostic study. Although the median and interquartile range (IQR) AHI from the device (7.0, 3.9-11.6 events/hr) was only slightly less than the PSG AHI (7.8, 3.9-14.4 events/hr, P = 0.04) during titration, case-by-case agreement between the two measures was poor (chi-square < 0.001). Conclusion: In a clinical sample control of OSA during APAP titration is often poor, and close clinical follow-up is particularly needed in patients with a history of cardiac disease or with high arousal or central apnea indices on the diagnostic study. Device AHI does not reliably assess control during APAP titration, and PSG assessment may be required if clinical response to treatment is poor. The findings relate to the ResMed AutoSet device and may not apply to other devices. Citation: Huang HCC; Hillman DR; McArdle N. Control of OSA during automatic positive airway pressure titration in a clinical case series: predictors and accuracy of device download data. SLEEP 2012;35(9):1277–1283. PMID:22942506

Huang, Hsin-Chia Carol; Hillman, David R.; McArdle, Nigel

2012-01-01

392

Isothermal titration calorimetry study of a bistable supramolecular system: reversible complexation of cryptand[2.2.2] with potassium ions.  

PubMed

Isothermal titration calorimetry (ITC) is used to investigate the thermodynamics of the complexation of potassium ions by 1,10-diaza-4,7,13,16,21,24-hexaoxabicyclo[8.8.8]hexacosane (cryptand[2.2.2]) in aqueous solution. By changing the pH of the solution it was possible to trigger the reversible complexation/decomplexation of the cryptand in consecutive in situ experiments and to assess for the first time the use of ITC to monitor the thermodynamics of a bistable system. PMID:24986754

del Rosso, Maria G; Ciesielski, Artur; Colella, Silvia; Harrowfield, Jack M; Samorì, Paolo

2014-09-15

393

Development of a new certified reference material of diosgenin using mass balance approach and Coulometric titration method.  

PubMed

Certified reference materials (CRMs) can be used as a valuable tool to validate the trueness of measurement methods and to establish metrological traceability of analytical results. Diosgenin has been selected as a candidate reference material. Characterization of the material relied on two different methods, mass balance method and Coulometric titration method (CT). The certified value of diosgenin CRM is 99.80% with an expanded uncertainty of 0.37% (k=2). The new CRM of diosgenin can be used to validate analytical methods, improve the accuracy of measurement data and control the quality of diosgenin in relevant pharmaceutical formulations. PMID:25174784

Gong, Ningbo; Zhang, Baoxi; Hu, Fan; Du, Hui; Du, Guanhua; Gao, Zhaolin; Lu, Yang

2014-12-01

394

K+ conductance modified by a titratable group accessible to protons from the intracellular side of the squid axon membrane.  

PubMed Central

In the range of pH examined (5.2-10), variations of internal pH from high to low values result in a reversible decrease of the conductance of the open K channels, without significantly affecting the kinetics parameters. A linear plot of the conductance versus internal pH suggests the existence of a titratable group that has an apparent pKa of about 6.9, and that is accessible to protons only from the intracellular side of the membrane. PMID:45399

Wanke, E; Carbone, E; Testa, P L

1979-01-01

395

Aggregation property of glycyrrhizic acid and its interaction with cyclodextrins analyzed by dynamic light scattering, isothermal titration calorimetry, and NMR.  

PubMed

The structural properties of glycyrrhizic acid, a sweet-tasting constituent of Glycyrrhiza glabra, and its interaction with cyclodextrins were analyzed using dynamic light scattering, isothermal titration calorimetry, and NMR. The dynamic light scattering and NMR studies showed that glycyrrhizic acid forms a water-soluble aggregate that disperses upon the addition of ?-cyclodextrin. The high sweetness of glycyrrhizic acid can be closely correlated with this aggregation, because the multimers of glycyrrhizic acid can simultaneously bind to the sweet taste receptors on the human tongue. The isothermal titration calorimetry experiments demonstrated that ?-cyclodextrin binds to glycyrrhizic acid more strongly than ?-cyclodextrin, however, both reactions are accompanied by a favorable change in binding entropy. Considering the large negative change in heat capacity that is observed during the binding of ?-cyclodextrin, the main driving force for the binding is hydrophobic interactions with dehydration, which is typical for inclusion complex. NMR experiments showed that ?-cyclodextrin interacts with the central part of the aglycone moiety, not the glucuronic acid moieties, resulting in high binding affinity. It should also be noted that the two distinct complexes of glycyrrhizic acid with ?-cyclodextrin would exist in aqueous solution. PMID:24844630

Izutani, Yusuke; Kanaori, Kenji; Oda, Masayuki

2014-06-17

396

Surfactant/detergent titration analysis method and apparatus for machine working fluids, surfactant-containing wastewater and the like  

DOEpatents

The present invention is an improved method and related apparatus for quantitatively analyzing machine working fluids and other aqueous compositions such as wastewater which contain various mixtures of cationic, neutral, and/or anionic surfactants, soluble soaps, and the like. The method utilizes a single-phase, non-aqueous, reactive titration composition containing water insoluble bismuth nitrate dissolved in glycerol for the titration reactant. The chemical reaction of the bismuth ion and glycerol with the surfactant in the test solutions results in formation of micelles, changes in micelle size, and the formation of insoluble bismuth soaps. These soaps are quantified by physical and chemical changes in the aqueous test solution. Both classical potentiometric analysis and turbidity measurements have been used as sensing techniques to determine the quantity of surfactant present in test solutions. This method is amenable to the analysis of various types of new, in-use, dirty or decomposed surfactants and detergents. It is a quick and efficient method utilizing a single-phase reaction without needing a separate extraction from the aqueous solution. It is adaptable to automated control with simple and reliable sensing methods. The method is applicable to a variety of compositions with concentrations from about 1% to about 10% weight. It is also applicable to the analysis of waste water containing surfactants with appropriate pre-treatments for concentration. 1 fig.

Smith, D.D.; Hiller, J.M.

1998-02-24

397

Surfactant/detergent titration analysis method and apparatus for machine working fluids, surfactant-containing wastewater and the like  

DOEpatents

The present invention is an improved method and related apparatus for quantitatively analyzing machine working fluids and other aqueous compositions such as wastewater which contain various mixtures of cationic, neutral, and/or anionic surfactants, soluble soaps, and the like. The method utilizes a single-phase, non-aqueous, reactive titration composition containing water insoluble bismuth nitrate dissolved in glycerol for the titration reactant. The chemical reaction of the bismuth ion and glycerol with the surfactant in the test solutions results in formation of micelles, changes in micelle size, and the formation of insoluble bismuth soaps. These soaps are quantified by physical and chemical changes in the aqueous test solution. Both classical potentiometric analysis and turbidity measurements have been used as sensing techniques to determine the quantity of surfactant present in test solutions. This method is amenable to the analysis of various types of new, in-use, dirty or decomposed surfactants and detergents. It is a quick and efficient method utilizing a single-phase reaction without needing a separate extraction from the aqueous solution. It is adaptable to automated control with simple and reliable sensing methods. The method is applicable to a variety of compositions with concentrations from about 1% to about 10% weight. It is also applicable to the analysis of waste water containing surfactants with appropriate pre-treatments for concentration.

Smith, Douglas D. (Knoxville, TN); Hiller, John M. (Oak Ridge, TN)

1998-01-01

398

An explicit formulation approach for the analysis of calcium binding to EF-hand proteins using isothermal titration calorimetry.  

PubMed

We present an improved and extended version of a recently proposed mathematical approach for modeling isotherms of ligand-to-macromolecule binding from isothermal titration calorimetry. Our approach uses ordinary differential equations, solved implicitly and numerically as initial value problems, to provide a quantitative description of the fraction bound of each competing member of a complex mixture of macromolecules from the basis of general binding polynomials. This approach greatly simplifies the formulation of complex binding models. In addition to our generalized, model-free approach, we have introduced a mathematical treatment for the case where ligand is present before the onset of the titration, essential for data analysis when complete removal of the binding partner may disrupt the structural and functional characteristics of the macromolecule. Demonstration programs playable on a freely available software platform are provided. Our method is experimentally validated with classic calcium (Ca(2+)) ion-selective potentiometry and isotherms of Ca(2+) binding to a mixture of chelators with and without residual ligand present in the reaction vessel. Finally, we simulate and compare experimental data fits for the binding isotherms of Ca(2+) binding to its canonical binding site (EF-hand domain) of polycystin 2, a Ca(2+)-dependent channel with relevance to polycystic kidney disease. PMID:24359756

Keeler, Camille; Poon, Gregory; Kuo, Ivana Y; Ehrlich, Barbara E; Hodsdon, Michael E

2013-12-17

399

[Titration curves (ph gradient electrophoresis) of SHV-1 and SHV-2 beta-lactamases and a new type].  

PubMed

The molecular structures of the SHV-1 (p 453) and SHV-2 (pBP 60-1) beta-lactamases and of a new enzyme, a SHV-2 like extended broad-spectrum beta-lactamase (86-4), were compared by analysis of their titration curves (pH gradient electrophoresis). The titration curves of SHV-1 and SHV-2, which have the same isoelectric points (pI = 7.7). were completely superimposable for the whole of the pH gradient (pH 3.5-10), indicating a close homology between the two proteins, with perhaps the substitution of several amino acids by ones having the same charge. The curves of SHV-1 (pI = 7.7) and the new SHV-2-like enzyme (pI = 6.98) indicated that a basic residue in SHV-1 has been replaced by an acidic residue in the new SHV-2-like enzyme. These results show that, like SHV-2, the new beta-lactamase is a variant of SHV-1, and that the structural differences are probably limited to a very small number of amino acid residues. Nevertheless, this new beta-lactamase (SHV-3) may have arisen directly from SHV-1, indirectly via SHV-2, or even from another beta-lactamase. PMID:3043330

Vedel, G; Picard, B; Paul, G; Gilly, L; Goullet, P; Nevot, P

1988-05-01

400

An Explicit Formulation Approach for the Analysis of Calcium Binding to EF-Hand Proteins Using Isothermal Titration Calorimetry  

PubMed Central

We present an improved and extended version of a recently proposed mathematical approach for modeling isotherms of ligand-to-macromolecule binding from isothermal titration calorimetry. Our approach uses ordinary differential equations, solved implicitly and numerically as initial value problems, to provide a quantitative description of the fraction bound of each competing member of a complex mixture of macromolecules from the basis of general binding polynomials. This approach greatly simplifies the formulation of complex binding models. In addition to our generalized, model-free approach, we have introduced a mathematical treatment for the case where ligand is present before the onset of the titration, essential for data analysis when complete removal of the binding partner may disrupt the structural and functional characteristics of the macromolecule. Demonstration programs playable on a freely available software platform are provided. Our method is experimentally validated with classic calcium (Ca2+) ion-selective potentiometry and isotherms of Ca2+ binding to a mixture of chelators with and without residual ligand present in the reaction vessel. Finally, we simulate and compare experimental data fits for the binding isotherms of Ca2+ binding to its canonical binding site (EF-hand domain) of polycystin 2, a Ca2+-dependent channel with relevance to polycystic kidney disease. PMID:24359756

Keeler, Camille; Poon, Gregory; Kuo, Ivana Y.; Ehrlich, Barbara E.; Hodsdon, Michael E.

2013-01-01

401

Adaptations to hypercapnic conditions in the nutria (Myocastor coypus)--in vivo and in vitro CO2 titration curves.  

PubMed

Arterial blood acid-base status of unanesthetized, unrestrained nutria was studied during exposure to 5, 10 and 14.5% CO2 for 6 hr. Control values, pH = 7.426 +/- 0.037, PaCo2 = 36.5 +/- 3.1 mmHg and [HCO-3] = 24.3 +/- 2.5 mM/1 (n = 24), are within the normal range reported for other mammals. Values after 6 hr of exposure to 10% CO2 were: pH = 7.355 +/- 0.043, PaCO2 = 71.0 +/- 3.6 mmHg and [HCO-3] = 38.0 +/- 4.1 mM/l (n = 5). Arterial blood buffer slopes, obtained from the in vitro titration curve, did not show any pattern of adaptation to hypercapnia. Whole body buffer slopes, calculated from the in vivo CO2 titration curve, showed significantly higher values for the nutria than for the rat, dog and man, under comparable conditions [beta(delta HCO-3/delta pH)] = 57.0 slykes for nutria, 32.6 for rat and 11.8 for man. delta H+/delta PaCO2 = 0.38. mM/l/mmHg for nutria, 0.55 for rat and 0.76 for man. The results suggest that the nutria possesses an efficient metabolic mechanism for regulation of pH level during exposure to hypercapnic conditions. PMID:6137314

Bar-Ilan, A; Marder, J

1983-01-01

402

Retardation signal for fluorescent determination of total protein content via rapid and sensitive chip moving reaction boundary electrophoretic titration.  

PubMed

A novel concept and theory of moving reaction boundary (MRB) retardation signal (RMRB) was advanced for determination of total protein content via MRB electrophoretic titration (MRBET). The theoretical results revealed that the retardation extent of boundary displacment, viz., the RMRB value, was as a function of protein content. Thus, the RMRB value of a sample could be used to determine its total protein content according to the relevant calibration curve. To demonstrate the concept and theoretical results, a novel microdevice was designed for the relevant experiments of MRBET. The microdevice has 30 identical work cells, each of which is composed of five ultrashort single microchannels (5 mm). In the microdevice, fluorescein isothiocyanate (FITC) was used to denote MRB motion and RMRB value for the first time, the polyacrylamide gel (PAG) containing protein sample was photopolymerized in microchannels, and the MRB was created with acid or alkali and target protein sample. As compared to the classic Kjeldahl method and conventional MRBET performed in glass tube, the developed titration chip has the following merits: good sensitivity (0.3-0.4 ?g/mL vs 150-200 ?g/mL of protein concentration, 0.6-0.8 ng vs 30-2000 ?g of absolute protein content), rapid analysis (20-60 s vs 15-200 min), and portable low-power (15 V vs 200 V). PMID:24512429

Wang, Houyu; Shi, Yongting; Yan, Jian; Dong, Jingyu; Li, Si; Xiao, Hua; Xie, Haiyang; Fan, Liu-Yin; Cao, Cheng-Xi

2014-03-18

403

Gaussianity, non-Gaussianity, and photometric redshift surveys  

NASA Astrophysics Data System (ADS)

Many physical properties of galaxies correlate with one another, and these correlations are often used to constrain galaxy formation models. However, the transformation from observable to physical quantity is frequently distance- dependent. Noise in the distance estimate leads to biased estimates of these correlations, thus compromising the ability of photometric redshift surveys to constrain galaxy formation models. Enabling a reliable estimate of these correlations from photometric data, and presenting methods and algorithms for estimating the correlations between distance-dependent observables accurately even if the distance estimate is noisy, is the main focus of the first part of this thesis. Noise properties are also essential in the second part, where we turn our attention to the pursuit of primordial non-Gaussianity in the Cosmic Microwave Background. There are already a number of plausible extensions of the standard inflationary model or alternative early universe models that predict skewed primordial fluctuations, but since the detection of primordial non-Gaussian fluctuations in the CMB would have a profound impact on our understanding of the physics of the early universe, these claims need to be further investigated. Therefore, it is vitally important to test whether the map of the primary temperature anisotropies is indeed Gaussian, as if it is not this fact would indicate a quite different structure formation scenario from the standard inflation model. We investigate the Gaussian hyphothesis using the clustering statistics of pixels and peaks that lie above or below a threshold. It turns out that a careful accounting for the effects of noise is crucial to performing this test. In the case of WMAP, the noise is spatially inhomogeneous; the present work shows how to incorporate this complexity into the analysis. Small differences from the Gaussian-based prediction remain even after this more careful accounting of the noise. While these may indicate primordial non- Gaussianity, we discuss a variety of plausible reasons for these discrepancies. Lastly, in the third part we present a blend of analytic and numerical tools in order to describe the shapes of dark matter halos as seen in the simulations. Shape measurements are useful, as they have important implications for interpretation of gravitational lensing measurements as well as observations of the Sunyaev-Zeldovich effect. In particular, the ellipsoidal collapse model is extended to study halo shapes, and combined with the statistics of Gaussian random fields. By averaging over the correct, mass-dependent distribution of initial shape parameters, each evolved through the ellipsoidal collapse model, we are able to make predictions for how the distribution of final shapes depends on halo mass.

Rossi, Graziano

404

Spectral classification of photometrically selected AGB candidates in NGC 6822  

NASA Astrophysics Data System (ADS)

Context. The ratio of C- and M-type asymptotic giant branch (AGB) stars is commonly used to estimate the metallicity of extragalactic populations. Sources in the AGB population must therefore be accurately classified as either C- or M-type. Spectroscopic data are presented for candidate C- and M-type AGB stars, previously classified using JHK photometry, in the Local Group dwarf galaxy NGC 6822. Aims: This paper aims to evaluate the success of the JHK classification criteria used in order to determine the level of error associated with this method, and to refine the criteria for future studies. The success rate of a second independent method of source classification, the CN-TiO method, is also examined. We also review the validity of the 4 kpc radial limit imposed in our previous work. Methods: Spectra of 323 sources, distributed across an area of 2 deg2, were taken using the AAOmega multi-fibre spectrograph on the Anglo-Australian Telescope and have been classified using an automated classification system and spectral standards from the literature. Nearly half (135) of these sources were selected in common with a photometric catalogue that relied on the CN-TiO method. Results: Within this sample we were able to classify 158 sources, including 82 C-type giants and one anomalous M-type giant, all members of NGC 6822, and 75 foreground K- and M-type dwarf sources. All but three of the giant sources are located within 3 kpc of the galactic centre. Using this spectroscopic sample, new JHK photometric criteria for the isolation and classification of C- and M-type AGB stars have been derived. The error rate in the CN-TiO method, arising from stars incorrectly classified as C-type, has been estimated to be ~7%. Conclusions: Based on the new JHK classification criteria, revised estimates of the global C/M ratio, 0.95 ± 0.04, and iron abundance, -1.38 ± 0.06 dex, are presented for NGC 6822. Tables 1, and 10-13 are available in electronic form at http://www.aanda.org

Sibbons, L. F.; Ryan, S. G.; Napiwotzki, R.; Thompson, G. P.

2015-02-01

405

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.; a larger Team

2014-01-01

406

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 fun- damental stellar parameters, Teff, logg, 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 re- peated 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 ˜9,000 stellar variables (including ˜3,000 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 ˜67,000 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, A.

407

Estimating iron and aluminum content of acid mine discharge from a north-central Pennsylvania coal field by use of acidity titration curves  

USGS Publications Warehouse

Determination of acidity provides a value that denotes the quantitative capacity of the sample water to neutralize a strong base to a particular pH. However, much additional information can be obtained from this determination if a titration curve is constructed from recorded data of titrant increments and their corresponding pH values. The curve can be used to identify buffer capabilities, the acidity with respect to any pH value within the curve limit, and, in the case of acid mine drainage from north-central Pennsylvania, the identification and estimation of the concentration of dissolved ferrous iron, ferric iron, and aluminum. Through use of titration curves, a relationship was observed for the acid mine drainage between: (1) the titratable acidity (as milligrams per liter calcium carbonate) to pH 4.0 and the concentration of dissolved ferric iron; and (2) the titratable acidity (as milligrams per liter calcium carbonate) from pH 4.0 to 5.0 and the concentration of dissolved aluminum. The presence of dissolved ferrous iron can be detected by the buffering effect exhibited in the area between pH 5.5 to 7.5. The concentration of ferrous iron is estimated by difference between the concentrations of ferric iron in an oxidized and unoxidized sample. Interferences in any of the titrations from manganese, magnesium, and aluminate, appear to be negligible within the pH range of interest.

Ott, A.N.

1986-01-01

408

Can We Measure Galaxy Environments with Photometric Redshifts?  

E-print Network

A variety of methods have been proposed to define and to quantify galaxy environments. While these techniques work well in general with spectroscopic redshift samples, their application to photometric redshift surveys remains uncertain. To investigate whether galaxy environments can be robustly measured with photo-z samples, we quantify how the density measured with the nearest neighbor approach is affected by photo-z uncertainties by using the Durham mock catalogs in which the 3D real-space environments and the properties of galaxies are exactly known. Furthermore, we present an optimization scheme in the choice of parameters used in the 2D projected measurements which yields the tightest correlation with respect to the 3D real-space environments. By adopting the parameters in the density measurements, we show that the correlation between the 2D projected optimized density and real-space density can still be revealed, and the color-density relation is also visible even for a photo-z uncertainty ($\\sigma_{\\De...

Lai, Chuan-Chin; Jian, Hung-Yu; Chiueh, Tzi-Hong; Merson, Alex; Baugh, Carlton; Foucaud, Sebastien; Chen, Chin-Wei; Chen, Wen-Ping

2015-01-01

409

Ccd Photometric Study and Period Investigation of V508 Oph  

NASA Astrophysics Data System (ADS)

In this paper, new CCD photometric observations of V508 Oph obtained in 2009 and 2010 at the Xinglong Observatory are presented. From the new observations, six new times of minimum light were derived. The light curves were analyzed by using the 2003 version of the Wilson–Devinney program. It is found that the asymmetric light curves can be modeled by a hot spot on the secondary component. The degree of overcontact is 15.4%, implying that the system is a shallow-contact binary. Combining the new times of minimum light with the photoelectric and CCD data compiled from the database, we investigate its orbital period. The results show that the orbital period may be undergoing multiple changes: a long-term decrease at a rate of dP/dt=-(1.502+/- 0.063)× {{10}-7} days year?1, and a small periodic variation with a period of 24.27(±0.34) years. Since V508 Oph is an overcontact system and both components are late-type stars, we discuss the possible connection between the mass transfer, magnetic activity, the third body, and the orbital period changes.

Xiang, Fu-Yuan; Yu, Yun-Xia; Xiao, Ting-Yu

2015-02-01

410

Photometric Properties of Face-on Isolated Spiral Galaxies  

NASA Astrophysics Data System (ADS)

We want to quantify the relative role of nature versus nurture in defining the observed properties of galaxies. In simpler terms we would like to disentangle the ``genetic'’ and the environmental influences in shaping the morphology of galaxies. In order to do that one needs to firstly define a zero-order baseline, i.e., a sample of galaxies that have been minimally perturbed by neighbors in the last few billion years of their existence. Such a sample has been produced and refined in different stages in the context of the AMIGA international project (www.iaa.es/AMIGA.html). The recent catalogue ``The All-Sky Catalog of Isolated Galaxies Selected from 2MASS'’ (Karachentseva, V. E. et al. 2010) allows us to complete and enrich the initial sample constructed within AMIGA with new objects, thus enhancing the statistical relevance of our study. Our focus is to define a subset of isolated disk spiral galaxies. We constrain the sample selection by: 1) orientation, restricting to almost face-on galaxies and 2) availability of good photometric images in SDSS. The goal is to ``dissect'’ (decompose) these galaxies in major components (disk, bulge, bars, etc.) and to study the properties of the components in a statistical context. Having a reasonable representation of all morphological types, we aim to test the bimodality of bulges and bars. We present a progress report of our work.

Bahr, Alexander; Epstein, P.; Durbala, A.

2011-05-01

411

Rotation and photometric properties of E-type asteroids  

NASA Astrophysics Data System (ADS)

The results of photometric observations of seven E-type asteroids 64 Angelina, 214 Aschera, 1025 Riema, 1103 Sequoia, 1251 Hedera, 2035 Stearns, and 2248 Dwornik are presented. New rotation periods have been determined for asteroids 1025 Riema (6.557±0.001 h) , 1251 Hedera (15.015±0.010 h) , 2035 Stearns (85.0±0.1 h), and 2048 Dwornik (3.664±0.001 h) . Two new poles have been estimated for 214 Aschera (274±8°; 64±4°) and 1025 Riema (141±10°, 11±6°) and pole has been redefined for 64 Angelina (138±10°, 31±5°). Using all available data on rotation periods, the spin rates of E-type asteroids have been analyzed. The distribution of the spin rates has maximum corresponding to the period of about 6.2 h. The shapes of E-asteroids are more elongated than the shapes of small-size S-asteroids. The average values of color indexes, albedo and G parameter for E-type asteroids have also been determined.

Shevchenko, V. G.; Krugly, Yu. N.; Chiorny, V. G.; Belskaya, I. N.; Gaftonyuk, N. M.

2003-08-01

412

Photometrical evolution of periodic comet 17P/Holmes  

NASA Astrophysics Data System (ADS)

Comet Holmes was discovered by Edwin Holmes on Nov. 6, 1892 during a large outburst. On Jan. 16, 1893 a second outburst occurred. During the following appearances in 1899 and 1906 the comet was faint (only 13m and 15m, respectively). The comet was last observed on Dec. 7, 1906. After the 1906 apparition the comet was lost. B. G. Marsden found that a close Jupiter passage on Dec. 9, 1908 changed the comet's orbit considerably. He predicted the next comet's appearance in 1964. The comet was recovered on July 16, 1964 using Marsden's prediction. The comet has been observed at every return since 1964. During the appearance in 2007 the comet had shown a unique outburst of amplitude about 15m on Oct. 24, 2007. Authors constructed and studied the light curve of integrated visual brightness of comet 17P/Holmes during appearance in 2007. The values of photometrical parameters H0, n, and H10 were computed for all observed comet's appearances. The secular variation of cometary brightness was studied. The quasi-periodicity of the cometary activity is discussed. The total light curve and light curve of outbursts were compared with variation of solar activity indexes. The results of our CCD observations of comet Holmes are discussed also. The results obtained by authors are important for development of outburst mechanism of this comet.

Filonenko, V.; Churyumov, K.

2008-09-01

413

Photometric modal discrimination in Delta Scuti and Gamma Doradus stars  

E-print Network

The potential of photometric methods for the identification of l, the degree of spherical surface harmonic of a pulsating star, is investigated with special emphasis on Stromgren photometry applied to delta Scuti and gamma Dor variables. Limitations of actual model atmospheres when fine precision is required for the calculations of partial derivatives and integrals, which depend on limb darkening coefficients, are discussed. Two methods are discussed to calculate the phase lags, the angle between maximum temperature and minimum radius, and R, a parameter which describes departure from adiabaticity of the atmospheres of these pulsating stars. These quantities appear to be very dependent on the convection as parametrized by the mixing length theory. When one of the methods is applied to the gamma Dor stars gives phase lags close to 0 degrees, which are 90-180 degrees out of phase from typical delta Scuti stars. Examples are given for some High Amplitude Delta Scuti Stars (HADS) where the method can be easily applied and gives results consistent to interpret them as radial (l=0) pulsating stars. Other low amplitude delta Scuti stars could be oscillating in a non-radial (l=1, 2) mode. Multi-band photometry is concluded to be a very powerful tool for mode identification of delta Scuti and gamma Dor stars, specially with the more accurate photometry that will be achieved in the near future with the asteroseismological space missions now in progress.

Rafael Garrido

2000-01-05

414

The SDSS Coadd: A Galaxy Photometric Redshift Catalog  

SciTech Connect

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 {approx} 13 million objects classified as galaxies in the coadd with r < 24.5. The photo-z and photo-z error estimators are trained and validated on a sample of {approx} 89, 000 galaxies that have SDSS photometry and spectroscopic redshifts measured by the SDSS Data Release 7 (DR7), the Canadian Network for Observational Cosmology Field Galaxy Survey (CNOC2), the Deep Extragalactic Evolutionary Probe Data Release 3(DEEP2 DR3), the SDSS-III's Baryon Oscillation Spectroscopic Survey (BOSS), the Visible imaging Multi-Object Spectrograph - Very Large Telescope Deep Survey (VVDS) and the WiggleZ Dark Energy Survey. For the best ANN methods we have tried, we find that 68% of the galaxies in the validation set have a photo-z error smaller than {sigma}{sub 68} = 0.036. After presenting our results and quality tests, we provide a short guide for users accessing the public data.

Reis, Ribamar R.R.; /Fermilab /Rio de Janeiro Federal U.; Soares-Santos, Marcelle; /Fermilab /Inst. Geo. Astron., Havana /Sao Paulo U.; Annis, James; /Fermilab; Dodelson, Scott; /Fermilab /Chicago U. /Chicago U., KICP; Hao, Jiangang; /Fermilab; Johnston, David; /Fermilab; Kubo, Jeffrey; /Fermilab; Lin, Huan; /Fermilab; Seo, Hee-Jong; /UC, Berkeley; Simet, Melanie; /Chicago U.

2011-11-01

415

A photometric search for solar giant convection cells  

NASA Technical Reports Server (NTRS)

The photometric contrast of solar giant convection cells is limited using 526.6 nm continuum images obtained on 15 days in May 1985. The rms of the giant cell intensity pattern must be less than or equal to the observed rms on spatial scales of 80 to 240 Mm, which is 0.023 percent or, equivalently, 0.33 K. However, the spatial scale and time-scale dependence of the variance demonstrate that giant cells are not the source of the observed variance. Consequently, a tighter constraint on the rms of the giant cell pattern may be placed, namely 0.016 percent or 0.23 K. This limit is consistent with temperature perturbations estimated from recent nonlinear simulations of global-scale solar convection. This limit on the rms of the giant cell pattern is used to estimate that the contribution of giant cells to the fluctuation of the solar irradiance on a one-month time-scale is less than 0.00003 S.

Chiang, W.-H.; Petro, L. D.; Foukal, P. V.

1987-01-01

416

Dynamical and photometric investigation of cometary type 2 tails  

NASA Technical Reports Server (NTRS)

The absolute calibration of the photometric profile of the antitail of Comet Kohoutek 1973 XII on plates taken with the Curtis Schmidt telescope of the University of Michigan at the Cerro Tololo Inter-American Observatory is described in detail. The formula for the determination of the air mass, and the correction for atmospheric absorption and for the loss of light due to vignetting are included. The calibration stars were used to derive the coefficients converting the relative intensity scale to the absolute surface-brightness units. The extensive results of the study of the orbital evolution of vaporizing dust particles are listed in a tabular form. Gradual evaporation from the surface of a particle results typically in its expulsion from the solar system. The properties of the particle and the elements of its orbit at expulsion are given as functions of the particle's properties and orbit before appreciable evaporation commenced. Also given are circumstances at an encounter of an expelled particle with the earth as a function of the particle's properties. A few specific cases are represented graphically.

Sekanina, Z.

1975-01-01

417

CCD photometric study of a contact binary HH Ursae Majoris  

NASA Astrophysics Data System (ADS)

New complete BV light curves of a poorly investigated contact binary HH Ursae Majoris (HH UMa) are presented. The light curves are analyzed by using the 2003 version of the Wilson-Devinney (W-D) code. Combining with the radial velocity published by the previous investigators, we obtain the photometric solution of the system. The solution indicates that HH UMa is a W-type W UMa system with a mass ratio of q=m2/m1=3.344 and a contact degree of 31.9%. The system has a very low inclination of i=53.035° and a temperature difference of 247 K between two components. The asymmetry of the light curves can be explained by adding a hot spot located near the neck region of the more massive component. A period investigation based on all available data shows that the period increases at a rate of dP/dt=2.84×10-7 days yr-1, which can be explained by mass transfer from the less massive component to the more massive one. We also give the absolute parameters of the system.

Han, Quanwang; Li, Lifang; Kong, Xiaoyang; Gong, Xiaobo; Zhao, Ruijuan

2014-08-01

418

Photometric and Spectroscopic Analysis of the Eclipsing Binary DQ Velorum  

NASA Astrophysics Data System (ADS)

In order to obtain the main stellar and orbital parameters of the Double Periodic Variable DQ Velorum, we have carried out a series of spectroscopic and photometric observations covering several orbital cycles. We disentangle DQ Vel composite spectra and measure radial velocities using an iterative method for double spectroscopic binaries. We obtain the spectroscopic mass ratio q=0.31±0.03 from the radial velocity curves. We compare our single-lined spectra with a grid of synthetic spectra and estimate the temperature of the stars. We also model the V-band light curve using a fitting method based on the simplex algorithm including an accretion disc. We find that DQ Vel is a semi-detached system consisting on a B3V gainer (T_{g}=18500±500 K) and an A1III donor star (T_{d}=9400±100 K) plus an extended accretion disc around the gainer. We compare the stellar and disc parameters of DQ Vel with the DPV V393 Sco to investigate the nature and evolution of these two similar DPV systems.

Barría, D.; Mennickent, R. E.; Schmidtobreick, L.; Djuraševi?, G.; Ko?aczkowski, Z.; Michalska, G.; Vu?kovi?, M.; Niemczura, E.

419

A Photometric Study of the Vesta Family of Asteroids  

NASA Astrophysics Data System (ADS)

Statistical analysis, spectroscopic studies, and imaging data, all uniquely suggest an impact origin for the Vesta family of asteroids. In order to constrain numerical models of family formation, and uncover the basic principles of asteroid evolution, we have begun a photometric study of 4 Vesta and the asteroids that comprise its family. The collected lightcurves, color data, and subsequent shape analysis, will help to address whether the Vesta chips are intact spall fragments (having a thin, elongated shape) or re-accumulated rubble piles (having roughly spherical, ellipsoidal, or lumpy shapes). The implications of these data will later be examined using an existing numerical hydrocode model (Melosh, et al., 1992) to better understand the family's impact origin. Thus far, we have obtained and reduced lightcurves for 10 of the Vesta-family asteroids using the 1.8-meter Vatican Advanced Technology Telescope (VATT) at the Mount Graham International Observatory. This set of lightcurves has been analyzed to determine asteroid rotation rates, which were found to range from very short (< 3 hours) to > 9 hours. Further, rotationally resolved color data have been collected on approximately 50% of our program asteroids. These data are in the process of being analyzed in order to determine if the Vesta chips appear spectrally homogenous, a possible indication of random, rubble pile reaccumulation, or retain distinct color variations that could be indicative of intact spall fragments. This work is supported by NASA Planetary Astronomy grant NAG5-8734 and the Vatican Observatory Research Group.

Ryan, W. H.; Ryan, E. V.; Martinez, C. T.

2000-10-01

420

Modeling Large Scale Structure from Photometric Galaxy Surveys  

NASA Astrophysics Data System (ADS)

We present our measurements and analysis for the systematic tests, the galaxy two-point angular correlation function, and the best halo-occupation distribution (HOD) model fit for galaxies and compact galaxy groups selected from the seventh data release of the Sloan Digital Sky Survey. We update the flag criteria to select a clean galaxy catalog and detail specific tests that we perform to characterize systematic effects, including the effects of seeing, Galactic extinction, stellar contamination, and the overall survey uniformity. We then measure the correlation function for the full sample as well as for the four magnitude bins. We find that the systematic signals are well below the galaxy angular correlation function for angles less than approximately 5°, which limits the modeling of galaxy angular correlations on larger scales. We then analyze the clustering of photometrically selected galaxy pairs by using the HOD model. We measure the two-point auto-correlation functions, ?(?), for galaxies and galaxy pairs and develop an HOD to model their clustering in dark matter halos. Our results are successfully fit by these HOD models, and we see the separation of "1-halo" and "2-halo" clustering terms for both single galaxies and galaxy pairs. With the information that we obtain from the best fit of HOD model, we can further put constrains on the current cosmology model and improve our understanding of galaxy clustering and formation.

Wang, Yiran; Brunner, Robert

2015-01-01

421

Predicting the Yields of Photometric Surveys for Transiting Planets  

E-print Network

Observing extrasolar planetary transits is one of the only ways that we may infer the masses and radii of planets outside the Solar System. As such, the detections made by photometric transit surveys are one of the only foreseeable ways that the areas of planetary interiors, system dynamics, migration, and formation will acquire more data. Predicting the yields of these surveys therefore serves as a useful statistical tool. Predictions allows us to check the efficiency of transit surveys (``are we detecting all that we should?'') and to test our understanding of the relevant astrophysics (``what parameters affect predictions?''). Furthermore, just the raw numbers of how many planets will be detected by a survey can be interesting in its own right. Here, we look at two different approaches to modeling predictions (forward and backward), and examine three different transit surveys (TrES, XO, and Kepler). In all cases, making predictions provides valuable insight into both extrasolar planets and the surveys themselves, but this must be tempered by an appreciation of the uncertainties in the statistical cut-offs used by the transit surveys.

Thomas G. Beatty

2008-07-01

422

MULTIBAND PHOTOMETRIC AND SPECTROSCOPIC ANALYSIS OF HV Cnc  

SciTech Connect

In this paper, radial velocity and VI- and JHK{sub S} - (Two Micron All Sky Survey) band photometric data of the detached system HV Cnc have been analyzed. The primary component of HV Cnc, which is a member of the M67 cluster, is suspected to be either a blue straggler or turn-off star. The system is a single-lined spectroscopic binary and its light curve shows a total eclipse. Spectroscopic observations of the system revealed the third component, which shows contribution to the total light of the system. Light curve and radial velocity data have been analyzed using the Wilson-Devinney (W-D) code and JHK{sub S} filter definitions computed for the W-D code in this work. Our analysis shows that the mass and radius of the primary and secondary components are 1.31 M {sub ?}, 0.52 M {sub ?}, 1.87 R {sub ?}, and 0.48 R {sub ?}, respectively. All results are compared with previously published literature values and discussed.

Gökay, G.; Gürol, B.; Derman, E., E-mail: ggokay@science.ankara.edu.tr [Astronomy and Space Sciences Department, Faculty of Science, Ankara University, 06100 Tando?an, Ankara (Turkey)

2013-11-01

423

Lunar photometric modelling with SMART-1/AMIE imaging data  

NASA Astrophysics Data System (ADS)

We investigate the light-scattering properties of the lunar mare areas. A large photometric dataset was extracted from images taken by the AMIE camera on board the SMART-1 spacecraft. Inter-particle shadowing effects in the regolith are modelled using ray-tracing simulations, and then a phase function is fit to the data using Bayesian techniques and Markov chain Monte Carlo. Additionally, the data are fit with phase functions computed from radiative-transfer coherent-backscatter (RT-CB) simulations. The results indicate that the lunar photometry, including both the opposition effect and azimuthal effects, can be explained well with a combination of inter-particle shadowing and coherent backscattering. Our results produce loose constraints on the mare physical properties. The RT-CB results indicate that the scattering volume element is optically thick. In both the Bayesian analysis and the RT-CB fit, models with lower packing density and/or higher surface roughness always produce better fits to the data than densely packed, smoother ones.

Wilkman, O.; Muinonen, K.; Videen, G.; Josset, J.-L.; Souchon, A.

2014-10-01

424

Infrared photometric behavior and opposition effect of Mars  

NASA Technical Reports Server (NTRS)

Although the instrument wasn't designed for this purpose, data from the imaging spectrometer ISM may be used for studying photometric variations of Mars reflectance, that are related to the surface materials and aerosols physical properties. ISM flew aboard the Phobos-2 spacecraft which orbited Mars from January to March, 1989. About 40,000 spectra were acquired in 128 channels ranging from 0.76 to 3.16 micro-m, with a spatial resolution of 25 km and a signal-to-noise ratio ranging up to 1000. Analysis of the results leads to the following conclusions: width variations of the opposition surge can be related to differences in porosity or grain size distribution on the various domains, with little or no effect from suspended dust. As the biggest effects are observed on dark and bright materials, intermediate behaviors on average-bright regions cannot result from a mixing process, but are more likely to come from either cementation processes or modification of the grain size distribution under the influence of wind, which under Martian conditions preferentially removes the biggest particles. Thus, a surface dust consisting in big bright and small dark grains could explain the observations.

Erard, S.; Bibring, J-P.; Drossart, P.

1992-01-01

425

61 FR 54120 - Appeals Procedures; Hearings Procedures  

Federal Register 2010, 2011, 2012, 2013, 2014

...RIN 1004-AC99 Appeals Procedures; Hearings Procedures AGENCY: Bureau of Land Management...contests, appeals of BLM decisions and hearings. The proposed regulations provide more...the appellants, BLM and the Office of Hearings and Appeals (OHA). DATES:...

1996-10-17

426

Color-redshift Relations and Photometric Redshift Estimations of Quasars in Large Sky Surveys  

E-print Network

With a recently constructed composite quasar spectrum and the \\chi^2 minimization technique, we demonstrated a general method to estimate the photometric redshifts of a large sample of quasars by deriving the theoretical color-redshift relations and comparing the theoretical colors with the observed ones. We estimated the photometric redshifts from the 5-band SDSS photometric data of 18678 quasars in the first major data release of SDSS and compare them with the spectroscopic redshifts. The redshift difference is smaller than 0.1 for 47% of quasars and 0.2 for 68 % of them. Based on the calculation of the theoretical color-color diagrams of stars, galaxies and quasars in both the SDSS and BATC photometric systems, we expected that with the BATC system of 15 intermediate filters we would be able to select candidates of high redshift quasars more efficiently than in the SDSS, provided the BATC survey could detect objects with magnitude fainter than 21.

Xue-Bing Wu; Wei Zhang; Xu Zhou

2003-07-24

427

M2 Research internship 2015 Estimation of the photometric properties for digitized  

E-print Network

M2 Research internship ­ 2015 Estimation of the photometric properties for digitized 3D objects conditions that is sufficiently reliable and robust. Internship goal The first objective of this internship

Allègre, Rémi

428

Photometric and Spectroscopic Behavior of V407 Cygni during 2010-2012  

NASA Astrophysics Data System (ADS)

We present the results of new UBVRIJHKLM photometric and spectroscopic observations of the recurrent symbiotic Nova V407 Cyg obtained during its nebular stage. Different types of the brightness variability are analyzed.

Shugarov, S.; Esipov, V. F.; Kolotilov, E. A.; Komissarova, G. V.; Shenavrin, V. I.; Tarasova, T. N.; Tatarnikov, A. M.; Tatarnikova, A. A.

2014-12-01

429

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

Code of Federal Regulations, 2011 CFR

21 Food and Drugs 8 2011-04-01... Discrete photometric chemistry analyzer for clinical... Section 862.2160 Food and Drugs FOOD AND DRUG ADMINISTRATION...MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL...

2011-04-01

430

Increasing the Detection Limit of the Parkinson Disorder through a Specific Surface Chemistry Applied onto Inner Surface of the Titration Well  

PubMed Central

The main objective of this paper was to illustrate the enhancement of the sensitivity of ELISA titration for neurodegenerative proteins by reducing nonspecific adsorptions that could lead to false positives. This goal was obtained thanks to the association of plasma and wet chemistries applied to the inner surface of the titration well. The polypropylene surface was plasma-activated and then, dip-coated with different amphiphilic molecules. These molecules have more or less long hydrocarbon chains and may be charged. The modified surfaces were characterized in terms of hydrophilic—phobic character, surface chemical groups and topography. Finally, the coated wells were tested during the ELISA titration of the specific antibody capture of the ?-synuclein protein. The highest sensitivity is obtained with polar (? = 35°), negatively charged and smooth inner surface. PMID:24955533

Mille, Caroline; Debarnot, Dominique; Zorzi, Willy; Moualij, Benaïssa El; Coudreuse, Arnaud; Legeay, Gilbert; Quadrio, Isabelle; Perret-Liaudet, Armand; Poncin-Epaillard, Fabienne

2012-01-01

431

Photometric Observations of Nova Mon 2012 = V959 Mon = Fermi J0639+0548  

NASA Astrophysics Data System (ADS)

Our multicolour photometric observations of V959 Mon enabled to determine more precise value of its orbital period as P = 0.d29576(3). The optical brightness variations with this period started in the beginning of 2012 October. The change in the shape of the orbital light curves in different photometric passbands during the light decline were analyzed. The positions of the object on a two-colour diagrams are shown.

Shugarov, S.; Pavlenko, E.; Chochol, D.; Malanushenko, V.; Rumiantseva, I.; Katysheva, N.

2014-12-01

432

A Photometrically Detected Forming Cluster of Galaxies at Redshift 1.6 in the GOODS Field  

Microsoft Academic Search

We report the discovery of a localized overdensity at z~1.6 in the GOODS-South field, presumably a poor cluster in the process of formation. The three-dimensional galaxy density has been estimated on the basis of well-calibrated photometric redshifts from the multiband photometric GOODS-MUSIC catalog using the (2+1)-dimensional technique. The density peak is embedded in the larger scale overdensity of galaxies known

M. Castellano; S. Salimbeni; D. Trevese; A. Grazian; L. Pentericci; F. Fiore; A. Fontana; E. Giallongo; P. Santini; S. Cristiani; M. Nonino; E. Vanzella

2007-01-01

433

Implementation of PhotoZ under Astro-WISE - A photometric redshift code for large datasets  

E-print Network

We describe the implementation of the PhotoZ code in the framework of the Astro-WISE package and as part of the Photometric Classification Server of the PanSTARRS pipeline. Both systems allow the automatic measurement of photometric redshifts for the millions of objects being observed in the PanSTARRS project or expected to be observed by future surveys like KIDS, DES or EUCLID.

Saglia, R P; Senger, R; Bender, R

2011-01-01

434

A Hand-held Photometric Stereo Camera for 3-D Modeling  

Microsoft Academic Search

This paper presents a simple yet practical 3-D model- ing method for recovering surface shape and reflectance from a set of images. We attach a point light source to a hand-held camera to add a photometric constraint to the multi-view stereo problem. Using the photometric con- straint, we simultaneously solve for shape, surface normal, and reflectance. Unlike prior approaches, we

Tomoaki Higo; Yasuyuki Matsushita; Neel Joshi; Katsushi Ikeuchi

2009-01-01

435

Photometric and spectroscopic observations of (2060) Chiron at the ESO Very Large Telescope  

Microsoft Academic Search

Photometric and spectroscopic observations of Centaur Chiron have been obtained at the ESO\\/Very Large Telescope (VLT), both in optical and near-infrared spectral ranges, on 12-14 June 2001. Photometric optical data reveal that Chiron had reached a high activity level at that time. No absorption feature could be seen on the spectra; especially, no water ice could be detected. Based on

J. Romon-Martin; C. Delahodde; M. A. Barucci; C. de Bergh; N. Peixinho

2003-01-01

436

VizieR Online Data Catalog: WASP-80 photometric and radial velocity data (Triaud+, 2013)  

NASA Astrophysics Data System (ADS)

The data is composed of one WASP photometric timeseries in a band similar to V+R, of two TRAPPIST photometric timeseries in the z band, and of one series from the EulerCam, in the Gunn r' filter. There is also one set of CORALIE radial velocities and one set of HARPS radial velocities. They give evidence of a planet orbiting and transiting WASP-80. (6 data files).

Triaud, A. H. M. J.; Anderson, D. R.; Collier, Cameron A.; Doyle, A. P.; Fumel, A.; Gillon, M.; Hellier, C.; Jehin, E.; Lendl, M.; Lovis, C.; Maxted, P. F. L.; Pepe, F.; Pollacco, D.; Queloz, D.; Segransan, D.; Smalley, B.; Smith, A. M. S.; Udry, S.; West, R. G.; Wheatley, P. J.

2013-01-01

437

VizieR Online Data Catalog: WASP-23 photometric and radial velocity data (Triaud+, 2011)  

NASA Astrophysics Data System (ADS)

The data is composed of 7 photometric timeseries and 2 set of radial velocities. 2 photometric timeseries originate from the WASP-South instrument, 2 from the Euler Telescope, 1 from the FTS telescope, 2 from the TRAPPIST telescope. The RVs come from the CORALIE spectrograph on the Euler Telescope, and from HARPS, on the ESO 3.6m They give evidence for the presence of a planet around WASP-23. (9 data files).

Triaud, A. H. M. J.; Queloz, D.; Hellier, C.; Gillon, M.; Smalley, B.; Hebb, L.; Collier, Cameron A.; Anderson, D.; Boisse, I.; Hebrard, G.; Jehin, E.; Lister, T.; Lovis, C.; Maxted, P. F. L.; Pepe, F.; Pollacco, D.; Segransan, D.; Simpson, E.; Udry, S.; West, R.

2011-03-01

438

Gusev photometric variability as seen from orbit by HRSC\\/Mars-express  

Microsoft Academic Search

Minnaert and two-term phase function Hapke models are used to describe the photometric properties of the martian surface using HRSC (High Resolution Stereo Camera) multi-angular observations acquired along the ongoing Mars-Express mission. These observations can be pieced together to derive integrated phase functions over a wide range of phase angles. The photometric diversity at 675 nm, as seen from orbit,

A. Jehl; P. Pinet; D. Baratoux; Y. Daydou; S. Chevrel; F. Heuripeau; N. Manaud; A. Cord; C. Rosemberg; G. Neukum; K. Gwinner; F. Scholten; H. Hoffman; T. Roatsch

2008-01-01

439