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1

A Low-Cost Device for Automatic Photometric Titrations  

NASA Astrophysics Data System (ADS)

Electronics is an important topic in chemistry courses. However, the introduction of basic concepts is often difficult and the lab instruments are frequently seen as "black boxes". To address this problem, we propose the construction of a simple, low-cost (about $150 U.S.) automatic photometric titrator employing a light-emitting diode (LED) and a phototransistor. The electronic circuit can be assembled by the students themselves. The device was employed to implement a common procedure in chemical labs, making feasible the introduction of concepts related to electronics in undergraduate chemistry courses. The titrator is able to work automatically, since a feedback system permits stopping the addition of titrant solution when the end-point is achieved. With this demonstration, it can be stressed that automatic procedures can be implemented without expensive instruments. Additionally, a classical procedure becomes more attractive to the students and its importance to chemical analysis can be emphasized. The feasibility of the titrator was demonstrated by acid-base titrations of HCl solutions with NaOH in the presence of phenolphthalein and by iodimetric determination of ascorbic acid in vitamin C tablets and lemon juice. Precise results (0.7% relative standard deviation, n = 10) in agreement at the 95% confidence level with those attained by a conventional procedure were obtained.

Rocha, Fábio R. P.; Reis, Boaventura F.

2000-02-01

2

Theoretical curves in indicator photometric titration of monodentate polyatomic ligands by metal ions  

SciTech Connect

On the basis of the law of mass action and material balance conditions, theoretical equations have been derived for the curves obtained in indicator photometric titration of anionic ligands by metal ions for the cases of formation of complexes ML, M/sub 2/L, and ML/sub 2/. Correspondence between theoretical and experimental titration curves has been demonstrated, thus making it possible to explain the factual material and to use reactions of low-stability complex formation in photometric titrations.

Kuznetsov, V.V.; Shamanskii, V.A.

1986-03-20

3

An Automatic Alignment Procedure for a 4Source Photometric Stereo Technique applied to Scanning Electron Microscopy  

Microsoft Academic Search

This paper presents an automatic alignment procedure for a 4-source photometric stereo technique to reconstruct the depth map in the scanning electron microscopy. PS, based on the so-called reflectance map, used several images of a surface to estimate the surface depth at each image point. Lambertian reflectivity function is the simplest one. In the SEM one of the most important

Ruggero Pintus; Simona Podda; Massimo Vanzi

2006-01-01

4

The role of serotonergic receptors in the effects of mu opioids in squirrel monkeys responding under a titration procedure  

Microsoft Academic Search

This experiment was conducted to determine whether drugs acting on brain serotonin modulate the effects of themu opioid, morphine, as measured by the squirrel monkey shock titration procedure and, if so, whether serotonergic modulation is mediated via specific 5HT receptor subtypes. Under this procedure, electric shock was delivered to the monkey's tail and scheduled to increase once every 15 s

K. R. Powell; L. A. Dykstra

1996-01-01

5

Equivalency testing of procedures for measuring free available chlorine: amperometric titration, DPD, and FACTS  

Microsoft Academic Search

The results of 192 analyses for free available chlorine were obtained from each of 16 participating laboratories. These data were statistically analyzed to determine whether the DPD, FACTS, and amperometric titration methods were equivalent. This analysis indicated that FACTS is equivalent to both DPD and amperometric titration.

William J. Cooper; Paul H. Gibbs; Edward M. Ott; Perin Patel

1983-01-01

6

Spectral sensitivity function measured by a rapid scan flicker photometric procedure.  

PubMed

A rapid scan flicker photometric procedure is described whereby continuous spectral sensitivity functions are measured from unpracticed observers in 30 min. The 30 min includes instructions, practice, and data collection. Data are presented from four unpracticed observers age 12 to 42 years. Three practiced observers had their spectral sensitivities measured by both the conventional and rapid scan methods. The conventional method took 1.5 hr, measuring at 25 wavelengths and repeating each three times. The agreement between the rapid scan and conventional methods is satisfactory. Comparison with Judd's correction of CIEV (lambda) yields the same deviations as expected with conventional flicker photometry. The rapid scan procedure is shown to yield acceptably consistent data. The advantages of the rapid scan method for basic and applied vision research is discussed. PMID:511467

Kaiser, P K

1979-12-01

7

An Automatic Alignment Procedure for a Four-Source Photometric Stereo Technique Applied to Scanning Electron Microscopy  

Microsoft Academic Search

This paper presents an automatic alignment procedure for a four-source photometric stereo (PS) technique for reconstructing the depth map in the scanning electron microscope (SEM). PS, which is based on the so-called reflectance map, used several images of a surface to estimate the surface depth at each image point, in which the Lambertian reflectivity function is the simplest. In the

Ruggero Pintus; Simona Podda; Massimo Vanzi

2008-01-01

8

Procedure for the quantitative determination of mixtures of nucleic Acid components based on multivariate spectrophotometric Acid-base titrations.  

PubMed

A new procedure for the quantitative determination of mixtures of nucleic acid components, based on continuous spectrophotometric acid-base titrations and multivariate curve resolution, is proposed. The procedure simultaneously takes into account the spectroscopic and acid-base properties of the compounds, which leads to a higher selectivity. Furthermore, quantitative determination of an analyte in a complex mixture is performed using a synthetic solution as standard containing only the analyte of interest. An intrinsic difficulty in the analysis of spectrometric titration data is the presence of rank deficiency due to closure for the mixtures of two or more compounds. An additional problem can be encountered in some mixtures if species spectra or species concentration profiles are practically identical (rank overlap). However, even in the presence of these rank difficulties, accurate quantitation with prediction errors lower than 5% was obtained. The presence of unknown and uncalibrated interferences in the samples does not affect the quantitative determination of the analyte of interest. The proposed procedure was successfully applied to the analysis of real samples (pharmaceuticals) using synthetic external standards. PMID:21662934

Saurina, J; Hernández-Cassou, S; Tauler, R; Izquierdo-Ridorsa, A

1999-01-01

9

Green Chemistry-Sensitive Analytical Procedure for Photometric Determination of Orthophosphate in River and Tap Water by Use of a Simple LED-Based Photometer  

Microsoft Academic Search

In the current work a Green Analytical Chemistry (GAC) procedure for photometric determination of orthophosphate in river water at µg L concentration level is described. The flow system module and the LED-based photometer were assembled together to constitute a compact unit in order to allow that a flow cell with optical path-length of 100 mm was coupled to them. The photometric

Milton B. Silva; Sivanildo S. Borges; Sheila R. W. Perdigão; Boaventura F. Reis

2009-01-01

10

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

PubMed

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 degrees C at different total concentrations of rhodamine B (5.89 x 10(-6) to 2.36 x 10(-4)M) and rhodamine 6G (2.34 x 10(-5) to 5.89 x 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 TDeltaS degrees -DeltaH degrees plot was sketched. It shows a fairly good positive correlation which indicates the enthalpy-entropy compensation in the dimerization reactions (compensation effect). PMID:16257772

Ghasemi, Jahanbakhsh; Niazi, Ali; Kubista, Mikael

2005-11-01

11

Protamine titration.  

PubMed

Protamine titration is the gold standard method for the measurement of unfractionated heparin (UFH) concentration in plasma. Protamine titration produces reliable and reproducible results; however it is -generally not considered a convenient assay for current clinical management of UFH as it is not readily automated (Olson et al. Arch Pathol Lab Med 122(9):782-798, 1998). Early clinical trials of UFH therapy determined that a heparin concentration of 0.2-0.4 U/ml by protamine titration correlated to an APTT of 1.5-2.5 times higher compared to baseline values produced desirable UFH safety and efficacy outcomes (Hull et al. N Engl J Med 315(18):1109-1114, 1986; Hull et al. N Engl J Med 322:1260-1264, 1990; Turpie et al. N Engl J Med 320:352-357, 1989; Brill-Edwards et al. Ann Intern Med 119(2):104-109, 1993; Hull Int Angiol 14(1):32-34, 1995). Such studies paved the way to the current view that it is no longer ideal to manage UFH based solely upon a 1.5-2.5 times prolongation of the "normal" APTT. Most advisory bodies recommend therapeutic APTTs be determined by correlating APTT results with therapeutic UFH levels as measured by anti-Xa assay (0.35-0.7 U/ml) or protamine titration (0.2-0.4 U/ml) (Hirsh and Raschke. Chest 126(3):188S-203S, 2004) (see Note 1). The concentration of UFH in a sample is measured by determining the amount of protamine required to return the thrombin clotting time (TCT) test (prolonged by UFH) to a pre-UFH level (Laffan and Manning. Dacie and Lewis: practical haematology. Churchill Livingstone: London, 2001). PMID:23546721

Newall, Fiona

2013-01-01

12

The Peculiar Motions of Early-Type Galaxies in Two Distant Regions. IV. The Photometric Fitting Procedure  

NASA Astrophysics Data System (ADS)

The EFAR project is a study of 736 candidate early-type galaxies in 84 clusters lying in two regions toward Hercules-Corona Borealis and Perseus-Cetus at distances cz ~ 6000--15,000 km s-1. In this paper we describe a new method of galaxy photometry adopted to derive the photometric parameters of the EFAR galaxies. The algorithm fits the circularized surface brightness profiles as the sum of two seeing-convolved components, an R1/4 and an exponential law. This approach allows us to fit the large variety of luminosity profiles displayed by the EFAR galaxies homogeneously and to derive (for at least a subset of these) bulge and disk parameters. Multiple exposures of the same objects are optimally combined and an optional sky-fitting procedure has been developed to correct for sky-subtraction errors. Extensive Monte Carlo simulations are analyzed to test the performance of the algorithm and estimate the size of random and systematic errors. Random errors are small, provided that the global signal-to-noise ratio of the fitted profiles is larger than ~300. Systematic errors can result from (1) errors in the sky subtraction, (2) the limited radial extent of the fitted profiles, (3) the lack of resolution due to seeing convolution and pixel sampling, (4) the use of circularized profiles for very flattened objects seen edge-on, and (5) a poor match of the fitting functions to the object profiles. Large systematic errors are generated by the widely used simple R1/4 law to fit luminosity profiles when a disk component, as small as 20% of the total light, is present. The size of the systematic errors cannot be determined from the shape of the chi 2 function near its minimum because extrapolation is involved. Rather, we must estimate them by a set of quality parameters, calibrated against our simulations, which take into account the amount of extrapolation involved to derive the total magnitudes, the size of the sky correction, the average surface brightness of the galaxy relative to the sky, the radial extent of the profile, its signal-to-noise ratio, the seeing value, and the reduced chi 2 of the fit. We formulate a combined quality parameter Q, which indicates the expected precision of the fits. Errors in total magnitudes MTOT less than 0.05 mag and in half-luminosity radii Re less than 10% are expected if Q = 1, and less than 0.15 mag and 25% if Q = 2; 89% of the EFAR galaxies have fits with Q = 1 or Q = 2. The errors on the combined fundamental plane quantity FP = log Re-0.3, where is the average effective surface brightness, are smaller than 0.03 even if Q = 3. Thus, systematic errors on MTOT and Re only have a marginal effect on the distance estimates that involve FP. We show that the sequence of R1/n profiles, recently used to fit the luminosity profiles of elliptical galaxies, is equivalent (for n <= 8) to a subsample of R1/4 and exponential profiles, with appropriate scale lengths and disk-to-bulge ratios. This suggests that the variety of luminosity profiles shown by early-type galaxies may be due to the presence of a disk component.

Saglia, R. P.; Bertschinger, Edmund; Baggley, G.; Burstein, David; Colless, Matthew; Davies, Roger L.; McMahan, Robert K., Jr.; Wegner, Gary

1997-03-01

13

Reproducibility of a Standardized Titration Procedure for the Initiation of Continuous Positive Airway Pressure Therapy in Patients with Obstructive Sleep Apnoea  

Microsoft Academic Search

Background: Manual titration of continuous positive airway pressure (CPAP) under polysomnographic control is the method most commonly employed to establish the minimal effective pressure (Peff) for the treatment of the obstructive sleep apnoea syndrome (OSA). To date, however, the reproducibility of Peff titrated in this way has not been investigated in any detail. Objectives: The present study aims to establish

G. H. Wiest; F. S. Fuchs; I. A. Harsch; S. Pour Schahin; S. Lampert; W. M. Brueckl; E. G. Hahn; J. H. Ficker

2001-01-01

14

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

Microsoft Academic Search

A sensitive and reproducible tissue culture biossay method was developed based on indirect immunofluorescence to titrate virus suspensions of the Junonia cœnia densovirus (JcDNV) and to quantify transfections by its cloned genomic DNA. Four lepidopteran cell lines, the SPC-SL 52 from Spodoptera littoralis, the SPC-PL 40 and the SPC-PL 65 cells derived from Spodoptera litura ovaries and hemocytes, respectively, and

Yi Li; Francoise-xavière Jousset; Catherine Giraud; Fabienne Rolling; Jean-marie quiot; Max Bergoin

1996-01-01

15

Coulometric Titration of Wustite.  

National Technical Information Service (NTIS)

The existence range and oxygen activity as functions of composition were determined for wustite from 765 to 965C by solid-electrolyte galvanic cell measurements. The composition changes were effected by coulometric titration. The results are in excellent ...

F. E. Rizzo J. V. Smith

1968-01-01

16

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

17

Acid Rain Analysis by Standard Addition Titration.  

ERIC Educational Resources Information Center

|The standard addition titration is a precise and rapid method for the determination of the acidity in rain or snow samples. The method requires use of a standard buret, a pH meter, and Gran's plot to determine the equivalence point. Experimental procedures used and typical results obtained are presented. (JN)|

Ophardt, Charles E.

1985-01-01

18

Acid Rain Analysis by Standard Addition Titration.  

ERIC Educational Resources Information Center

The standard addition titration is a precise and rapid method for the determination of the acidity in rain or snow samples. The method requires use of a standard buret, a pH meter, and Gran's plot to determine the equivalence point. Experimental procedures used and typical results obtained are presented. (JN)

Ophardt, Charles E.

1985-01-01

19

Neutron absorptiometric titration.  

PubMed

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

Tölgyessy, J; Varga, S; Dillinger, P

1967-03-01

20

Titration Curves: Fact and Fiction.  

ERIC Educational Resources Information Center

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

Chamberlain, John

1997-01-01

21

The ALHAMBRA Photometric System  

Microsoft Academic Search

This paper presents the characterization of the optical range of the ALHAMBRA photometric system, a 20 contiguous, equal-width, medium-band CCD system with wavelength coverage from 3500 Å to 9700 Å. The photometric description of the system is done by presenting the full response curve as a product of the filters, CCD, and atmospheric transmission curves, and using some first- and

T. Aparicio Villegas; E. J. Alfaro; J. Cabrera-Caño; M. Moles; N. Benítez; J. Perea; A. del Olmo; A. Fernández-Soto; D. Cristóbal-Hornillos; C. Husillos; J. A. L. Aguerri; T. Broadhurst; F. J. Castander; J. Cepa; M. Cerviño; R. M. González Delgado; L. Infante; I. Márquez; J. Masegosa; V. J. Martínez; F. Prada; J. M. Quintana; S. F. Sánchez

2010-01-01

22

Photometric determination of nitric acid in spent etching solutions from the production of filament lamps  

SciTech Connect

The etching of molybdenum cores in the production of tungsten spirals for filament lamps leads to solutions which contain, besides molybdenum (up to 10%) and traces of tungsten, large quantities of unreacted nitric and sulfuric acids. These solutions cannot be analyzed following the earlier procedure for the determination of mixtures of nitric and sulfuric acids because they are strongly colored which makes titration difficult and because the proposed titrant, lead nitrate, precipitates molybdates and tungstates. The proposed method (Leute's method) has the following drawbacks: the use of ferro iron as the indicator does not give clear equivalence points in the titration and when the solution is boiled, in accordance with this procedure, the complex itself is decomposed and iron(II) is oxidized. The procedure developed by the authors in this paper eliminates the boiling and thus eliminates oxidation of iron(II) with oxygen from the air. The color of the solutions obtained is stable for 48 h which allows the authors to determine photometrically the concentration of nitric acid.

Kochetkova, T.M.; Sazonova, N.N.

1986-11-01

23

Radiometric acid-base titrations.  

PubMed

Acid-base titrations can be performed with radiometric end-point detection by use of labelled metal salts (e.g., ZnCl(2), HgCl(2)). Owing to the formation or dissolution of the corresponding hydroxide after the equivalence point, the activity of the titrated solution linearly increases or decreases as excess of standard solution is added. The end-point of the titration is determined graphically. PMID:18960522

Erdey, L; Gimesi, O; Szabadváry, F

1969-03-01

24

Conductometric Titration of Chlorhexidine and Proguanil  

Microsoft Academic Search

Conductometric titrations of chlorhexidine and proguanil are reported. The procedure is based on the copper-bi-guanide reaction which gives a pink solid. Studies at several pH values, and presence of NH3 and ethanol are carried out. 3 ml of 0.2 M NH3, 9ml of 0.01 M NaOH diluted to 60 mL with 15% ethanol are added to 5ml of biguenide aqueous

J. Matrtinez Calatayud; P. Campins Falcó; M. C. Pascual Martí

1986-01-01

25

THE ALHAMBRA PHOTOMETRIC SYSTEM  

SciTech Connect

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

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

2010-03-15

26

The ALHAMBRA Photometric System  

NASA Astrophysics Data System (ADS)

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

Aparicio Villegas, T.; Alfaro, E. J.; Cabrera-Caño, J.; Moles, M.; Benítez, N.; Perea, J.; del Olmo, A.; Fernández-Soto, A.; Cristóbal-Hornillos, D.; Husillos, C.; Aguerri, J. A. L.; Broadhurst, T.; Castander, F. J.; Cepa, J.; Cerviño, M.; González Delgado, R. M.; Infante, L.; Márquez, I.; Masegosa, J.; Martínez, V. J.; Prada, F.; Quintana, J. M.; Sánchez, S. F.

2010-03-01

27

Sodium Determination Using Ion Selective Electrodes, Mohr Titration, and Test Strips  

NASA Astrophysics Data System (ADS)

Sodium content of foods can be determined by various methods, including an ion selective electrode (ISE), the Mohr or Volhard titration procedure, or indicator test strips. These methods are official methods of analysis for numerous specific products. All these methods are faster and less expensive procedures than analysis by atomic absorption spectroscopy or inductively coupled plasma-atomic emission spectroscopy. This experiment allows one to compare sodium analysis of several food products by ISE, Mohr titration, and Quantab® chloride titrators.

Nielsen, S. Suzanne

28

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

29

Amperometric, Bipotentiometric, and Coulometric Titration.  

ERIC Educational Resources Information Center

Discusses recent review articles in various kinds of titration. Also discusses new research in apparatus and methodology, acid-base reactions, precipitation and complexing reactions, oxidation-reduction reactions, and nomenclature. Cites 338 references. (CS)

Stock, John T.

1980-01-01

30

Amperometric, Bipotentiometric, and Coulometric Titration.  

ERIC Educational Resources Information Center

|Discusses recent review articles in various kinds of titration. Also discusses new research in apparatus and methodology, acid-base reactions, precipitation and complexing reactions, oxidation-reduction reactions, and nomenclature. Cites 338 references. (CS)|

Stock, John T.

1980-01-01

31

A Critical Assessment of Photometric Redshift Methods: A CANDELS Investigation  

NASA Astrophysics Data System (ADS)

We present results from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) photometric redshift methods investigation. In this investigation, the results from 11 participants, each using a different combination of photometric redshift code, template spectral energy distributions (SEDs), and priors, are used to examine the properties of photometric redshifts applied to deep fields with broadband multi-wavelength coverage. The photometry used includes U-band through mid-infrared filters and was derived using the TFIT method. Comparing the results, we find that there is no particular code or set of template SEDs that results in significantly better photometric redshifts compared to others. However, we find that codes producing the lowest scatter and outlier fraction utilize a training sample to optimize photometric redshifts by adding zero-point offsets, template adjusting, or adding extra smoothing errors. These results therefore stress the importance of the training procedure. We find a strong dependence of the photometric redshift accuracy on the signal-to-noise ratio of the photometry. On the other hand, we find a weak dependence of the photometric redshift scatter with redshift and galaxy color. We find that most photometric redshift codes quote redshift errors (e.g., 68% confidence intervals) that are too small compared to that expected from the spectroscopic control sample. We find that all codes show a statistically significant bias in the photometric redshifts. However, the bias is in all cases smaller than the scatter; the latter therefore dominates the errors. Finally, we find that combining results from multiple codes significantly decreases the photometric redshift scatter and outlier fraction. We discuss different ways of combining data to produce accurate photometric redshifts and error estimates.

Dahlen, Tomas; Mobasher, Bahram; Faber, Sandra M.; Ferguson, Henry C.; Barro, Guillermo; Finkelstein, Steven L.; Finlator, Kristian; Fontana, Adriano; Gruetzbauch, Ruth; Johnson, Seth; Pforr, Janine; Salvato, Mara; Wiklind, Tommy; Wuyts, Stijn; Acquaviva, Viviana; Dickinson, Mark E.; Guo, Yicheng; Huang, Jiasheng; Huang, Kuang-Han; Newman, Jeffrey A.; Bell, Eric F.; Conselice, Christopher J.; Galametz, Audrey; Gawiser, Eric; Giavalisco, Mauro; Grogin, Norman A.; Hathi, Nimish; Kocevski, Dale; Koekemoer, Anton M.; Koo, David C.; Lee, Kyoung-Soo; McGrath, Elizabeth J.; Papovich, Casey; Peth, Michael; Ryan, Russell; Somerville, Rachel; Weiner, Benjamin; Wilson, Grant

2013-10-01

32

Characterization of petroleum sulfonates by a nonaqueous titration method  

SciTech Connect

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 calculated from the grams of sample titrated and the moles of acid used. The potentiometric titration can be carried out in less than 10 minutes and can be done with 10 to 100 mg of sample. The accuracy and precision of the procedure were examined by the titration of sodium salts of p-toluene sulfonate, 2-naphthalene sulfonate, and petroleum sulfonates. In general, values for the equivalent weight were within 2% of those values determined by the Epton titration, by wet ashing methods, or from the theoretical value. The relative standard deviation (RSD) for the procedure is estimated to be 0.5%. For p-toluene sulfonate, an RSD of 0.15% was calculated. Petroleum sulfonates are used to liberate a residual oil from a porous medium in a tertiary oil-recovery process. 24 refs.

Voss, K.R.; Bricker, C.E.; Michnick, M.J.; Willhite, G.P.

1981-12-01

33

Potentiometric/turbidometric titration of antiperspirant actives.  

PubMed

A titration procedure that simultaneously monitors the pH and turbidity of an antiperspirant solution during neutralization with sodium hydroxide was developed to characterize antiperspirant actives. Aluminum chloride, aluminum chlorohydrate (ACH), and aluminum zirconium glycine complex (AZG) gave distinctive pH/turbidity profiles. The activated forms of aluminum chlorohydrate (ACH') and aluminum zirconium glycine complex (AZG') produced more turbidity than the non-activated forms. On an equimolar basis, AZG' produced more turbidity than any of the antiperspirant actives tested. PMID:12715089

Johnston, Clifford T; Hem, Stanley L; Guenin, Eric; Mattai, Jairajh; Afflito, John

34

Standard Asteroid Photometric Catalogue  

NASA Astrophysics Data System (ADS)

The Asteroid Photometric Catalogue (APC) is now in its fifth update with over 8600 lightcurves of more than 1000 asteroids in the database. The APC also has references of over one thousand lightcurves not in digital format. The catalogue has been published by Uppsala University Observatory and is distributed by request (contact: classe@astro.uu.se). The new update also includes a list of known asteroid rotational periods and a CD-ROM containing all the existing digital data in the APC. The total number of observed lightcurves is growing rapidly, not the least because of the new state-of-the-art equipment and growing interest among amateur astronomers. The photometric database is now so large that the present format must be altered to facilitate a user-friendly on-line service for the down- and uploading of data. We are proposing (and have started to construct) a new Internet-based Standard Asteroid Photometric Catalogue (SAPC). The website is planned to open during the first half of the year 2002. In addition to the data files, the site would contain the index and guide to the catalogue, a web-form for reporting observations, and some general observing guidelines (e.g., on filters, timing, etc.). There would also be a list of asteroids for which more observations are needed, together with recommended observing periods. This would be accompanied by an up-to-date collection of physical asteroid models based on photometric data, as well as links to observer network pages and other sites that work in collaboration with the catalogue project. Our aim is to develop this site into a global standard service used by everyone involved in asteroid photometry.

Piironen, J.; Lagerkvist, C.-I.; Torppa, J.; Kaasalainen, M.; Warner, B.

2001-12-01

35

Implementing Probabilistic Photometric Redshifts  

NASA Astrophysics Data System (ADS)

Photometric redshifts have become more important with the growth of large imaging surveys. But their basic implementation has not changed significantly from their original development, as most techniques provide a single estimate and a computed error for the source redshift. In this paper, we present a new approach that provides accurate probability density functions (PDF) of redshifts for galaxies taken from the DEEP2 survey by efficiently combining standard template fitting techniques with powerful machine learning methods in a new, fully probabilistic manner.

Carrasco Kind, M.; Brunner, R. J.

2013-10-01

36

Multiview Photometric Stereo  

Microsoft Academic Search

Abstract This paper addresses the problem of obtaining complete, detailed reconstructions of textureless shiny objects. We present an algorithm which uses silhouettes of the object, as well as images obtained under changing,illumination conditions. In contrast with previous photometric,stereo techniques, ours is not limited to a single viewpoint but pro duces accurate reconstructions in full 3D. A number of images of

Carlos Hernández Esteban; George Vogiatzis; Roberto Cipolla

2008-01-01

37

UVIS Photometric Zero Points  

NASA Astrophysics Data System (ADS)

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

Kalirai, Jasonjot

2008-07-01

38

Multiview photometric stereo.  

PubMed

This paper addresses the problem of obtaining complete, detailed reconstructions of textureless shiny objects. We present an algorithm which uses silhouettes of the object, as well as images obtained under changing illumination conditions. In contrast with previous photometric stereo techniques, ours is not limited to a single viewpoint but produces accurate reconstructions in full 3D. A number of images of the object are obtained from multiple viewpoints, under varying lighting conditions. Starting from the silhouettes, the algorithm recovers camera motion and constructs the object's visual hull. This is then used to recover the illumination and initialise a multi-view photometric stereo scheme to obtain a closed surface reconstruction. There are two main contributions in this paper: Firstly we describe a robust technique to estimate light directions and intensities and secondly, we introduce a novel formulation of photometric stereo which combines multiple viewpoints and hence allows closed surface reconstructions. The algorithm has been implemented as a practical model acquisition system. Here, a quantitative evaluation of the algorithm on synthetic data is presented together with complete reconstructions of challenging real objects. Finally, we show experimentally how even in the case of highly textured objects, this technique can greatly improve on correspondence-based multi-view stereo results. PMID:18195448

Hernández Esteban, Carlos; Vogiatzis, George; Cipolla, Roberto

2008-03-01

39

Analysis of photometric factors based on photometric linearization.  

PubMed

We propose a method for analyzing photometric factors, such as diffuse reflection, specular reflection, attached shadow, and cast shadow. For analyzing real images, we utilize the photometric linearization method, which was originally proposed for image synthesis. First, we show that each pixel can be photometrically classified by a simple comparison of the pixel intensity. Our classification algorithm requires neither 3D shape information nor color information of the scene. Then, we show that the accuracy of the photometric linearization can be improved by introducing a new classification-based criterion to the linearization process. Experimental results show that photometric factors can be correctly classified without any special devices. A further experiment shows that the proposed method is effective for photometric stereo. PMID:17912327

Mukaigawa, Yasuhiro; Ishii, Yasunori; Shakunaga, Takeshi

2007-10-01

40

Titrating-Delay Matching-to-Sample in the Pigeon  

PubMed Central

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 incorrect matches decrease the delay, and steady-state titrated delays serve as the primary dependent measure. The present series of experiments investigated the effects of several procedural variables on performance in TDMTS procedures in an effort to elucidate better its features to allow for more precision in future use. Experiment 1 reports results from a parametric analysis of fixed-ratio response requirements on the sample key that indicated improved remembering in the form of higher daily titrated delay values as the requirement was increased. Experiment 2 investigated the extent to which the initial delay value in each session affected session-wide delay values. Results indicated that regardless of value of the initial delay, the subjects' performances adjusted the delay values in the direction of the known baseline delay-value levels. Experiment 3 manipulated the step size by which delay values were adjusted and the results indicated that larger step sizes increased both session-to-session variability and within-session range of titrated delay values, although the average values remained approximately the same. These results suggest that the TDMTS task serves as a promising procedure to study what many refer to as memory.

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

2010-01-01

41

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

42

On the Photometric Calibration of FORS2 and the Sloan Digital Sky Survey  

NASA Astrophysics Data System (ADS)

An accurate absolute calibration of photometric data to place them on a standard magnitude scale is very important for many science goals. Absolute calibration requires the observation of photometric standard stars and analysis of the observations with an appropriate photometric model including all relevant effects. In the FORS Absolute Photometry (FAP) project, we have developed a standard star observing strategy and modelling procedure that enables calibration of science target photometry to better than 3% accuracy on photometrically stable nights given sufficient signal-to-noise. In the application of this photometric modelling to large photometric databases, we have investigated the Sloan Digital Sky Survey (SDSS) and found systematic trends in the published photometric data. The amplitudes of these trends are similar to the reported typical precision (˜1% and ˜2%) of the SDSS photometry in the griz- and u-bands, respectively.

Bramich, D.; Moehler, S.; Coccato, L.; Freudling, W.; Garcia-Dabó, C. E.; Müller, P.; Saviane, I.

2012-09-01

43

New chemical titration proposed for potassium mud testing  

Microsoft Academic Search

An accurate and easy-to-use procedure for measuring the potassium ion concentration in drilling and completion fluids has been developed and successfully used in Union Oil Co. of California's drilling operations. This volumetric analysis is based on the quantitative conversion of soluble sodium tetraphenylboron to the insoluble potassium tetraphenylboron and back titration with a quaternary ammonium salt in the presence of

Zilch

1984-01-01

44

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…

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

2006-01-01

45

Subpixel photometric stereo.  

PubMed

Conventional photometric stereo recovers one normal direction per pixel of the input image. This fundamentally limits the scale of recovered geometry to the resolution of the input image, and cannot model surfaces with subpixel geometric structures. In this paper, we propose a method to recover subpixel surface geometry by studying the relationship between the subpixel geometry and the reflectance properties of a surface. We first describe a generalized physically-based reflectance model that relates the distribution of surface normals inside each pixel area to its reflectance function. The distribution of surface normals can be computed from the reflectance functions recorded in photometric stereo images. A convexity measure of subpixel geometry structure is also recovered at each pixel, through an analysis of the shadowing attenuation. Then, we use the recovered distribution of surface normals and the surface convexity to infer subpixel geometric structures on a surface of homogeneous material by spatially arranging the normals among pixels at a higher resolution than that of the input image. Finally, we optimize the arrangement of normals using a combination of belief propagation and MCMC based on a minimum description length criterion on 3D textons over the surface. The experiments demonstrate the validity of our approach and show superior geometric resolution for the recovered surfaces. PMID:18566498

Tan, Ping; Lin, Stephen; Quan, Long

2008-08-01

46

SIMPLE FLOW INJECTION TITRATION METHOD BASED ON VARIATION OF THE SAMPLE VOLUME  

Microsoft Academic Search

A simple single-line flow injection system incorporating the fully rotary valve (FRV) has been developed for titration purposes. The FRV enables to inject the titrand solution to the titrant stream in four different volumes producing a set of four adequate analytical signals. Due to this fact the titration procedure can be performed with the use of only two standard solutions

Pawe? Ko?cielniak; Joanna Kozak

2002-01-01

47

Photometric Systems and Stellar Parameters  

NASA Astrophysics Data System (ADS)

Information on temperatures, gravities, metallicities, peculiarities and interstellar reddening of stars can be obtained by photometry of their light in a certain photometric system. A review of some photometric systems currently in use is given. The review includes the broad-band system UBV and its extension RI, the revised WBVR system and the medium-band Vilnius and Strömvil systems.

Straizys, V.

48

Photometric Stereo under Perspective Projection  

Microsoft Academic Search

Photometric stereo is a fundamental approach in Computer Vision. At its core lies a set of image irradiance equations each taken with a different illumination. The vast major- ity of studies in this field have assumed orthography as the projection model. This paper re-examines the basic set of equations of photometric stereo, under an assumption of perspective projection. We show

Ariel Tankus; Nahum Kiryati

2005-01-01

49

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

50

Surface Titrations of Perlite Suspensions  

Microsoft Academic Search

The surface charge behaviour of unexpanded and expanded perlite samples in KNO3and NaCl solutions were investigated as a function of pH and ionic strength. The solutions of KNO3and NaCl ranging from 10?3to 1.0Mwere used. The potentiometric titration method was used to determine the surface charge of perlite samples. It was confirmed that the perlite samples had no the point of

Mahir Alkan; Mehmet Do ?

1998-01-01

51

An elevated temperature titration calorimeter  

NASA Astrophysics Data System (ADS)

A variable-temperature (313 K to 353 K) titration calorimeter of high sensitivity has been constructed. The purpose of the calorimeter is to study temperature effects on the enthalpies of complex formation and of other reactions of metal cations such as hydrolysis and precipitation. Operation of the calorimetric system, including that final calculation of the heat released during titration, is automatic via computer control. Calibration tests of the calorimeter using 2-amino 2-hydroxymethyl 1,3-propanediol gave -(46.0 +/- 0.3) kJ/mol and -(46.2 +/- 0.2) kJ/mol for the enthalpy of protonation, at 318 K and at 343 K, respectively. For titrations of 2-bis(2-hydroxyethyl) amino 2-hydroxymethyl 1,3-propanediol, enthalpy of protonation values of -(28.4 +/- 0.3) kJ/mol and -(29.3 +/- 0.2) kJ/mol were obtained at 318 K and at 343 K, respectively.

Smith, J. R.; Zanonato, P. L.; Choppin, G. R.

1991-06-01

52

An elevated temperature titration calorimeter  

SciTech Connect

A variable-temperature (313 K to 353 K) titration calorimeter of high sensitivity has been constructed. The purpose of the calorimeter is to study temperature effects on the enthalpies of complex formation and of other reactions of metal cations such as hydrolysis and precipitation. Operation of the calorimetric system, including that final calculation of the heat released during titration, is automatic via computer control. Calibration tests of the calorimeter using 2-amino-2-hydroxymethyl-1,3-propanediol gave -(46.0 {plus minus} 0.3) kJ mol{sup {minus}1} and -(46.2 {plus minus} 0.2) kJ mol{sup {minus}1} for the enthalpy of protonation, at 318 K and at 343 K, respectively. For titrations of 2-bis(2-hydroxyethyl) amino-2-hydroxymethyl-1,3-propanediol, enthalpy of protonation values of -(28.4 {plus minus} 0.3) kJ mol{sup {minus}1} and -(29.3 {plus minus} 0.2) kJ mol{sup {minus}1} were obtained at 318 K and at 343 K, respectively. 6 refs., 3 figs., 2 tabs.

Smith, J.R.; Zanonato, P.L.; Choppin, G.R. (Florida State Univ., Tallahassee, FL (USA). Dept. of Chemistry)

1991-06-01

53

Automatic titrator for high precision plutonium assay  

SciTech Connect

Highly precise assay of plutonium metal is required for accountability measurements. We have developed an automatic titrator for this determination which eliminates analyst bias and requires much less analyst time. The analyst is only required to enter sample data and start the titration. The automated instrument titrates the sample, locates the end point, and outputs the results as a paper tape printout. Precision of the titration is less than 0.03% relative standard deviation for a single determination at the 250-mg plutonium level. The titration time is less than 5 min.

Jackson, D.D.; Hollen, R.M.

1986-01-01

54

Solid titration of octacalcium phosphate.  

PubMed

Octacalcium phosphate (OCP) is of considerable importance as a precursor in the formation of dental enamel and an intermediate phase in the precipitation of hydroxyapatite (HAp) in bone. However, agreement is poor on the solubility product (pK(sp)), possibly due to the formation of the more stable phase HAp. The system was investigated using solid titration, which has shown reliability in work on HAp and related fluoride minerals, with OCP in 100 mM KCl at 37.0 +/- 0.1 degrees C. The constitution of the end point precipitate was determined by X-ray diffraction and selected-electron area diffraction; the particle morphology and elements present were examined by high-resolution field emission scanning, transmission electron microscopy and energy-dispersive X-ray analysis. The titration curve for OCP was found for pH approximately 3.4-7.4. The precipitate was HAp at pH 3.6 and 4.5; no residual OCP or other phase was detected. Dicalcium phosphate dihydrate (DCPD) was then found to form at pH 3.6 on further addition of OCP titrant after equilibrium had been achieved, possibly due to easier nucleation at lower pH. However, markedly crystalline HAp was formed in equilibrium for OCP titration with HAp seeding, verifying HAp as the more stable phase. A solubility isotherm for OCP was not obtained as HAp appears to be less soluble in the pH range studied. This adds weight to the view that HAp may be the most stable phase of all calcium phosphates, with further doubt being cast on DCPD being the most stable phase below pH 4.2. However, metastable DCPD may form in an Ostwald succession, depending on supersaturation and nucleation conditions. PMID:19556792

Pan, H-B; Darvell, B W

2009-06-24

55

Galactic structure from photometric surveys.  

NASA Astrophysics Data System (ADS)

Seventeen of twenty known or suspected dwarf galaxy satellites of the Milky Way were discovered through photometric images. Six significant tidal streams are known in the Galactic spheroid, all of which were discovered through photometric surveys. At present, only photometric surveys provide enough sky coverage and depth to probe the shape of the Milky Way. We argue that the Virgo Stellar Stream, which might be a stream or a disrupting dwarf galaxy, has a center 14-19 kpc from the Sun in the direction (l,b)=(300o,64o), using photometry from the Sloan Digital Sky Survey (SDSS) and the Sloan Extension for Galactic Understanding and Exploration (SEGUE). In the process, we demonstrate the importance of large, deep, multi-color, public photometric sky surveys with precision color information. Currently, the most urgent need is for data in the southern hemisphere and at low Galactic latitude. Deeper surveys would also be useful.

Newberg, H. J.; Mayeur, P. A.; Yanny, B.; SEGUE Collaboration

56

Determination of Solanesol by Coulometric Titration  

Microsoft Academic Search

A method for determination of solanesol by coulometric titration was developed. The titration was carried out in a mixture of 2M KBr-glacial acetic acid (22:78 v\\/v), and bromine was generated at the anode. Solanesol reacted with bromine with a value of n = 18. The end point of the titration was detected with two-electrode amperometry. The method is rapid, accurate

Kuai Zhi Liu; Meng Liu; Deliang Li

1998-01-01

57

Precipitation titration of perchlorate using new titrants  

SciTech Connect

We have evaluated the following new titrants for the potentiometric precipitation titration of perchlorate: cetyltrimethylammonium chloride (CETAC), cetyltrimethylammonium bromide (CETAB), cetylpyridinium chloride (CPC), and benzyldimethyltetradecylammonium chloride (BDTAC). Titrations were monitored with a fluoroborate ion-selective electrode (ISE) and a double-junction reference electrode. The titration system was controlled by a Tektronix 4051 graphics system. The perchlorate, nitrate, and calcium ISE may also be used to monitor emf's. 7 tables, 2 figures.

Selig, W.

1980-05-01

58

Simultaneous determination of equivalence volumes and acid dissociation constants from potentiometric titration data.  

PubMed

New iterative methods for analysis of potentiometric titration data of (a) mixtures of weak monoprotic acids with their conjugate bases, (b) solutions of polyprotic (di- and triprotic) acids, and (c) mixtures of two diprotic acids are presented. These methods, using data exclusively resulting from the acidic region of the titration curve permits the accurate determination of the analytical concentration of one or more acids even if the titration is stopped well before the end point of the titration. For the titration of a solution containing a conjugate acid/base pair, the proposed procedure enables the extraction of the initial composition of the mixture, as well as the dissociation constant of the concerned acid. Thus, it is possible by this type of analysis to distinguish whether a weak acid has been contaminated by a strong base and define the extent of the contamination. On the other hand, for the titration of polyprotic acids, the proposed approach enables the extraction of the accurate values of the equivalence volume and the dissociation constants K(i) even when the ionization stages overlap. Finally, for the titration of a mixture of two diprotic acids the proposed procedure enables the determination of the composition of the mixture even if the sum of the concentrations of the acids is not known. This method can be used in the analysis of solutions containing two diastereoisomeric forms of a weak diprotic acid. The test of the proposed procedures by means of ideal and Monte Carlo simulated data revealed that these methods are fairly applicable even when the titration data are considerably obscured by 'noise' or contain an important systematic error. The proposed procedures were also successfully applied to experimental titration data. PMID:18966298

Papanastasiou, G; Ziogas, I

1995-06-01

59

Titration of long-chain quaternary ammonium compounds using tetraphenylboron  

Microsoft Academic Search

A rapid macro procedure for the determination of long-chain quaternary ammonium compounds (QAC) has been developed using sodium\\u000a tetraphenylboron as a titrant. About 1–1.5 meq of QAC is dissolved or dispersed in 50 ml of water. Dichlorofluorescein is\\u000a added as an indicator. The sample is then titrated with 0.06 N aqueous sodium tetraphenylboron. As long as free QAC is present

L. D. Metcalfe; R. J. Martin; A. A. Schmitz

1966-01-01

60

Assay of quaternary ammonium antimicrobial compounds by aqueous potentiometric titration  

Microsoft Academic Search

An automatic potentiometric titration method for the determination of quaternary ammonium antimicrobial compounds at the macro\\u000a level is described. The procedure involves the use of standard sodium lauryl sulfate as the titrant and a nitrate ion-selective\\u000a or surfactant electrode to detect the end point. The method, which includes a new, simpler means of titrant standardization,\\u000a avoids the use of hazardous

George T. Battaglini

2002-01-01

61

Isothermal Titration Calorimetry of RNA  

PubMed Central

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

Salim, Nilshad N.; Feig, Andrew L.

2009-01-01

62

Application of chemiluminescent indicators in EDTA titrations.  

PubMed

The chemiluminescent indicators lucigenine and luminol are readily applicable to end-point detection in the EDTA titration of cadmium, zinc and nickel ions. Back-titration with copper(II) gives reproducible results. The end-point is indicated by the disappearance of the green chemiluminescence of lucigenine, or by the appearance of the bluish luminescence of luminol. PMID:18960856

Erdey, L; Weber, O; Buzás, I

1970-12-01

63

CONSTANT CURRENT SOURCE FOR AUTOMATIC COULOMETRIC TITRATIONS  

Microsoft Academic Search

A simple but versatile constant current source for automatic coulometric ; titrations is described. The unit is suitable for use with a commercial ; automatic pH titrimeter and will accommodate wide variations of main voltage and ; load resistance. Coulometric titrations may be carried out fast'' or slow'' ; with a choice of four current ranges (2 to 37 ma)

A. R. Palmer; A. W. Pryor

1958-01-01

64

A Theoretical Photometric Function of Saturn'S Rings.  

National Technical Information Service (NTIS)

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

K. A. Haemeen-anttila P. Vaaraniemi

1974-01-01

65

Coulometric Determination of Protein Nitrogen Application to Direct Titration of Kjeldahl Digests  

Microsoft Academic Search

A coulometric method is described for the determination of ammonia resulting from micro-Kjeldahl digestion of protein samples. The method has been applied to the direct titration of the ammonia in the digests. Routine titration of the ammonia resulting from lO-?sl. serum samples is described; the method has been applied to 1-JLI.samples. Results are compared with standard macro- and micro-Kjeldahl procedures.

Gary D. Christian; Edward C. Knoblock; William C. Purdy

66

Visual photometric experiment data analysis  

NASA Astrophysics Data System (ADS)

The Visual Photometric Experiment (VIPER) is an instrument package designed for a shuttle-borne Get-Away Special canister. Data processing and analysis developments for the VIPER are described, including support for the camera and visual radiometer processing, pre-flight laboratory calibration, and development of the star field matching algorithm for the post flight pointing determination.

Mzaaella, Andrew J., Jr.; Larson, Kevin P.

1990-07-01

67

Photometric Stereo Without Multiple Images  

Microsoft Academic Search

Photometric Stereo (PMS) recovers orientation vectors from a set of graylevel images. Under orthography, whenthe lights are unknown, and for a single uniform Lambertian surface, one can recover surface normals up to anunknown overall orthogonal transformation. The same situation obtains if, instead of three graylevel images, oneuses a single RGB image taken with at least three point or extended colored

Mark S. Drew

1997-01-01

68

Passive Photometric Stereo from Motion  

Microsoft Academic Search

We introduce an iterative algorithm for shape reconstruc- tion from multiple images of a moving (Lambertian) object illuminated by distant (and possibly time varying) light- ing. Starting with an initial piecewise linear surface, the algorithm iteratively estimates a new surface based on the previous surface estimate and the photometric information available from the input image sequence. During each iter- ation,

Jongwoo Lim; Jeffrey Ho; Ming-hsuan Yang; David J. Kriegman

2005-01-01

69

Determining surface curvature with photometric stereo  

Microsoft Academic Search

A method is described to compute dense representations of the intrinsic curvature at each point on a visible surface, based on photometric stereo. The idea of photometric stereo is to use the intensity values recorded from multiple images obtained from the same viewpoint but under different conditions of illumination. Previously, photometric stereo has been used to obtain local estimates of

Robert J. Woodham

1989-01-01

70

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

71

Potentiometric Titration Method for Quantitative Determination of Hydrogen Peroxide.  

National Technical Information Service (NTIS)

An electrochemical potentiometric titration method that entails titration of a known volume of a catholyte containing an unknown amount of hydrogen peroxide in a titration cell having two electrodes, a platinum working electrode and a silver/silver chlori...

R. R. Bessette

2005-01-01

72

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

Microsoft Academic Search

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

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

2011-01-01

73

Effect of Cell Geometry in Coulometric Titrations.  

National Technical Information Service (NTIS)

In coulometric titrations the current flowing between the generator electrodes interferes with the operation of the indicator electrodes. In the case of parallel rod-shaped electrodes the error-signal curve that describes the extent of the interference ha...

D. Tamas

1974-01-01

74

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

National Technical Information Service (NTIS)

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

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

1974-01-01

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

Shape reconstruction from photometric stereo  

Microsoft Academic Search

Two iterative algorithms for shape reconstruction based on multiple images taken under different lighting conditions, known as photometric stereo, are proposed. It is shown that single-image shape-from-shading (SFS) algorithms have an inherent problem, i.e., the accuracy of the reconstructed surface height is related to the slope of the reflectance map function defined on the gradient space. This observation motivates the

Kyoung Mu Lee; C.-C. J. Kuo

1992-01-01

77

Photometric analysis of Abell 1689  

NASA Astrophysics Data System (ADS)

We carried out a photometric analysis of a sample of early-type galaxies in Abell~1689 at z = 0.183, using HST/ACS archive images in the rest-frame V band. We performed a two-dimensional photometric decomposition of each galaxy surface-brightness distribution using the GASP2D fitting algorithm (Méndez-Abreu et al. 2008). We adopted both a Sérsic and de Vaucouleurs law. S0 galaxies were analysed also taking into account a disc component described by an exponential law. The derived photometric parameters, together with the ones previously obtained with the curve of growth method (Houghton et al. 2012), will be used to analyse the Fundamental Plane of Abell 1689 and quantify how it is affected by the use of different decomposition techniques (Dalla Bontà et al. 2013, in preparation). The stellar velocity dispersions of the sample galaxies were derived by using GEMINI-N/GMOS and VLT/FLAMES (D'Eugenio et al. 2013) spectroscopic data.

Bontà, Elena Dalla; Davies, Roger L.; Houghton, Ryan C. W.; D'Eugenio, Francesco; Corsini, Enrico M.; Méndez-Abreu, Jairo

2013-07-01

78

40 CFR 60.648 - Optional procedure for measuring hydrogen sulfide in acid gas-Tutwiler Procedure. 1  

Code of Federal Regulations, 2010 CFR

...Optional procedure for measuring hydrogen sulfide in acid gas-Tutwiler Procedure...Optional procedure for measuring hydrogen sulfide in acid gasâTutwiler Procedure...method consists of titrating hydrogen sulfide in a gas sample directly...

2010-07-01

79

Theoretical investigation of the behavior of titratable groups in proteins.  

PubMed

This paper presents a theoretical analysis of the titration behavior of strongly interacting titratable residues in proteins. Strongly interacting titratable residues exist in many proteins such as for instance bacteriorhodopsin, cytochrome c oxidase, cytochrome bc(1), or the photosynthetic reaction center. Strong interaction between titratable groups can lead to irregular titration behavior. We analyze under which circumstances titration curves can become irregular. We demonstrate that conformational flexibility alone can not lead to irregular titration behavior. Strong interaction between titratable groups is a necessary, but not sufficient condition for irregular titration curves. In addition, the two interacting groups also need to titrate in the same pH-range. These two conditions together lead to irregular titration curves. The mutation of a single residue within a cluster of interacting titratable residues can influence the titration behavior of the other titratable residues in the cluster. We demonstrate this effect on a cluster of four interacting residues. This example underlines that mutational studies directed at identifying the role of a certain titratable residue in a cluster of interacting residues should always be accompanied by an analysis of the effect of the mutation on the titration behavior of the other residues. PMID:16761087

Klingen, Astrid R; Bombarda, Elisa; Ullmann, G Matthias

2006-04-12

80

Dense Photometric Stereo Using Tensorial Belief Propagation  

Microsoft Academic Search

Abstract We address the normal reconstruction problem by photometric stereo using a uniform and dense set of photometric images captured at flxed viewpoint. Our method,is robust to spurious noises caused by high- light and shadows and non-Lambertian re?ections. To simultaneously recover normal orientations and pre- serve discontinuities, we model the dense photometric stereo problem into two coupled Markov Random Fields

Kam-lun Tang; Chi-keung Tang; Tien-tsin Wong

2005-01-01

81

New ground-based photometric measurements  

NASA Astrophysics Data System (ADS)

The work undertaken on the ground based photometric measurements for the Hipparcos program is presented. The purposes of the work are, an input to the definition of the observing program, optimization of the observations by allocating observing time according to the stars' magnitudes, and the photometric reductions and calibrations of the satellite data. In the scope of the study the following topics are included: the prediction of the H(sub p) magnitude, the evaluation of the necessity of new photometric data, the choice of photometric systems, the organization, and the program management.

Grenon, M.

1989-06-01

82

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

83

Random Forests for Photometric Redshifts  

NASA Astrophysics Data System (ADS)

The main challenge today in photometric redshift estimation is not in the accuracy but in understanding the uncertainties. We introduce an empirical method based on Random Forests to address these issues. The training algorithm builds a set of optimal decision trees on subsets of the available spectroscopic sample, which provide independent constraints on the redshift of each galaxy. The combined forest estimates have intriguing statistical properties, notable among which are Gaussian errors. We demonstrate the power of our approach on multi-color measurements of the Sloan Digital Sky Survey.

Carliles, Samuel; Budavári, Tamás; Heinis, Sébastien; Priebe, Carey; Szalay, Alexander S.

2010-03-01

84

Photometric Determination of Quasar Candidates  

NASA Astrophysics Data System (ADS)

We describe an efficient and fast method for the detection and classification of quasars using a machine learning tool, making use of photometric information from SDSS DR7 data release. The photometric information used are the ten independent colours that can be derived from the 5 filters available with SDSS and the machine learning algorithm used is a difference boosting neural network (DBNN) that uses Bayesian classification rule. An adaptive learning algorithm was used to prepare the training sample for each region. Cross validations were done with SDSS spectroscopy and it was found that the method could detect quasars with above 96.96% confidence regarding their true classification. The completeness at this stage was 99.01%. Contaminants were mainly stars and the incorrectly classified quasars belonged to a few specific patches of redshifts. Color plots indicated that the colors of some stars and quasars in those redshits were indistinguishable from each other and was the major cause of their incorrect classification. A confidence value (computed posterior Bayesian belief of the network) was assigned to every object that was classified. Most of the incorrect classifications had a low confidence value. This information may be used to filter out contaminants and improve the classification accuracy at the cost of reduced completeness.

Abraham, S.; Philip, N. S.

2010-12-01

85

Titration of the bacteriorhodopsin Schiff base involves titration of an additional protein residue.  

PubMed

The retinal protein protonated Schiff base linkage plays a key role in the function of bacteriorhodopsin (bR) as a light-driven proton pump. In the unphotolyzed pigment, the Schiff base (SB) is titrated with a pK(a) of approximately 13, but following light absorption, it experiences a decrease in the pK(a) and undergoes several alterations, including a deprotonation process. We have studied the SB titration using retinal analogues which have intrinsically lower pK(a)'s which allow for SB titrations over a much lower pH range. We found that above pH 9 the channel for the SB titration is perturbed, and the titration rate is considerably reduced. On the basis of studies with several mutants, it is suggested that the protonation state of residue Glu204 is responsible for the channel perturbation. We suggest that above pH 12 a channel for the SB titration is restored probably due to titration of an additional protein residue. The observations may imply that during the bR photocycle and M photointermediate formation the rate of Schiff base protonation from the bulk is decreased. This rate decrease may be due to the deprotonation process of the "proton-releasing complex" which includes Glu204. In contrast, during the lifetime of the O intermediate, the protonated SB is exposed to the bulk. Possible implications for the switch mechanism, and the directionality of the proton movement, are discussed. PMID:15938637

Zadok, Uri; Asato, Alfred E; Sheves, Mordechai

2005-06-14

86

AMPEROMETRIC TITRATION OF THORIUM SALTS WITH CUPFERRON  

Microsoft Academic Search

Thorium forms with cupferron a precipitate of ThCupâ in a wide pH ; range in the absence of strong acids and sulfates. The precipitate has a ; tendency to form a colloid, and it is necessary to use coagulants; the most ; effective is sodium chloride. Sulfosalicylic acid is a stronger masking agent ; than citric acid during thorium titration

V. D. Vasilenko; E. B. Ostrovskaya; T. S. Fomenko

1961-01-01

87

Titration Calculations with Computer Algebra Software  

ERIC Educational Resources Information Center

|This article examines the symbolic algebraic solution of the titration equations for a diprotic acid, as obtained using "Mathematica," "Maple," and "Mathcad." The equilibrium and conservation equations are solved symbolically by the programs to eliminate the approximations that normally would be performed by the student. Of the three programs,…

Lachance, Russ; Biaglow, Andrew

2012-01-01

88

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

89

CCD Observations in the Vilnius Photometric System  

Microsoft Academic Search

Setting up the Vilnius photometric system with CCD detectors is extremely important for investigation of galactic structure since the system makes it possible to determine completely by photometric means spectral classes, absolute magnitudes, metallicities and peculiarity types of stars, even when affected by interstellar reddening. The paper describes the first observations made in the Vilnius system with CCD detectors at

R. P. Boyle; F. J. Vrba; F. Smriglio; A. K. Dasgupta; V. Straizys

1996-01-01

90

Photometric Stereo with General, Unknown Lighting  

Microsoft Academic Search

Work on photometric stereo has shown how to recover the shape and reflectance properties of an object using multiple images taken with a fixed viewpoint and variable lighting conditions. This work has primarily relied on the presence of a single point source of light in each image. In this pa- per we show how to perform photometric stereo assuming that

Ronen Basri; David W. Jacobs

2001-01-01

91

Dense Photometric Stereo by Expectation Maximization  

Microsoft Academic Search

We formulate a robust method using Expectation Maximiza- tion (EM) to address the problem of dense photometric stereo. Previous approaches using Markov Random Fields (MRF) utilized a dense set of noisy photometric images for estimating an initial normal to encode the matching cost at each pixel, followed by normal refinement by consid- ering the neighborhood of the pixel. In this

Tai-pang Wu; Chi-keung Tang

2006-01-01

92

Photometric Stereo with General, Unknown Lighting  

Microsoft Academic Search

Work on photometric stereo has shown how to recover the shape and reflectance properties of an object using multiple images taken with a fixed viewpoint and variable lighting conditions. This work has primarily relied on known lighting conditions or the presence of a single point source of light in each image. In this paper we show how to perform photometric

Ronen Basri; David W. Jacobs; Ira Kemelmacher

2007-01-01

93

Stellar physics with the ALHAMBRA photometric system  

Microsoft Academic Search

The ALHAMBRA photometric system was specifically designed to perform a tomography of the Universe in some selected areas. Although mainly designed for extragalactic purposes, its 20 contiguous, equal-width, medium-band photometric system in the optical wavelength range, shows a great capacity for stellar classification. In this contribution we propose a methodology for stellar classification and physical parameter estimation (Teff, log g,

T Aparicio Villegas; E J Alfaro; J Cabrera-Caño; M Moles; N Benítez; J Perea; A del Olmo; A Fernández-Soto; D Cristóbal-Hornillos; J A L Aguerri; T Broadhurst; F J Castander; J Cepa; M Cervio; R M González Delgado; L Infante; I Márquez; J Masegosa; V J Martínez; F Prada; J M Quintana; S F Sánchez

2011-01-01

94

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?

2007-04-08

95

Modification of a pH-Titration Standardization Method for Formaldehyde  

Microsoft Academic Search

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

Reimar R. W. Gaertner

1988-01-01

96

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

97

Potentiometric determination of weak bases by titration to a fixed pH value  

Microsoft Academic Search

The theoretical fundamentals of the pH-metric determination of weak bases by titration with solutions of strong acids to a\\u000a fixed pH value were considered. A simple and rapid procedure for determining ?-aminocaproic acid in medicinal preparations\\u000a was developed.

N. N. Golovnev; O. S. Romanova; N. V. Busygina

2000-01-01

98

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

99

Asteroid Photometric Catalogue. First update.  

NASA Astrophysics Data System (ADS)

The first version of the Asteroid Photometric Catalogue contained more than 2200 lightcurves of 357 asteroids (Lagerkvist et al., 1987, see 43.002.026). This updating of the catalogue adds more than 1200 new lightcurves published during 1986 - 1987 for 222 asteroids. For each asteroid in the catalogue the number, the rotation period, the range of the lightcurve amplitude, the absolute magnitude, the slope parameter, the diameter, U-B, B-V, the albedo and the taxonomic types as defined by Tholen (1988) and Barucci et al. (1987) are given. The observational circumstances and the aspect data as well as references tothe original publications are given in a table. Data both for the observation published 1985 - 1987 and the data published in the first version of the Catalogue are included in the table.

Lagerkvist, C.-I.; Barucci, M. A.; Capria, M. T.; Fulchignoni, M.; Magnusson, P.; Zappalà, V.

100

Titration calorimetry standards and the precision of isothermal titration calorimetry data.  

PubMed

Current Isothermal Titration Calorimetry (ITC) data in the literature have relatively high errors in the measured enthalpies of protein-ligand binding reactions. There is a need for universal validation standards for titration calorimeters. Several inorganic salt co-precipitation and buffer protonation reactions have been suggested as possible enthalpy standards. The performances of several commercial calorimeters, including the VP-ITC, ITC200, and Nano ITC-III, were validated using these suggested standard reactions. PMID:19582227

Baranauskiene, Lina; Petrikaite, Vilma; Matuliene, Jurgita; Matulis, Daumantas

2009-06-18

101

Telephone Titration of Heart Failure Medications.  

PubMed

BACKGROUND:: In clinical practice, heart failure (HF) medications are underused and prescribed at lower than recommended doses. Telephone care is an option that could help to titrate HF medication in a timely manner. We describe our experience of a nurse-run, cardiologist- or nurse practitioner-supervised clinic to up-titrate HF medications via telephone. METHODS:: Patients with the diagnosis of HF, New York Heart Association classes I to III, were referred to a registered nurse-run, cardiologist-/nurse practitioner-supervised HF medication titration clinic. Clinical and medication data collected at enrollment to the clinic and at 3 to 6 months after optimization of HF medications in patients who did or did not reach the target doses were compared. Effect on left ventricular (LV) function was also evaluated. RESULTS:: There were 79 patients in the evaluation: 64 with HF and LV systolic dysfunction (LVSD) and the remaining 15 with HF and preserved ejection fraction (EF). Seventy-two percent of patients with LVSD were on an angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB), and 61% were on a ?-blocker at baseline, and this increased to 98% and 97%, respectively, after optimization. Target doses was achieved in 50% of patients for ACEI or ARB, and in 41% for ?-blockers. The median time to optimization was 54 days (interquartile range, 20-97 days). The average number of phone calls at the time of optimization were 5.4 (SD, 3.7), and the average number of clinic visits was 1.9 (SD, 1.3). Reasons for not reaching the target doses included hypotension, hyperkalemia, and renal dysfunction for ACEI and bradycardia for ?-blockers. Overall, the EF increased by 10% (SD, 10%) after 6 months, and 35% or greater in 42% of patients whose baseline EF was less than 35%. There were no adverse events related to the dose up-titration. CONCLUSION:: Telephonic titration of HF medications was feasible and safe and was achieved in 97% patients on ACEI/ARB and ?-blockers. Medication titration was associated with significant improvement in LV function, avoiding the need for device therapy in many patients. PMID:21127425

Steckler, Anne E; Bishu, Kalkidan; Wassif, Heba; Sigurdsson, Gardar; Wagner, Judy; Jaenicke, Connie; Vats, Shashank; Rector, Thomas; Anand, Inder S

2010-12-01

102

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

103

Sloan Digital Sky Survey photometric telescope automation and observing software  

NASA Astrophysics Data System (ADS)

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

Neilsen, Eric H., Jr.; Uomoto, Alan; Kent, Steven M.; Annis, James T.

2002-12-01

104

Sodium Determination Using Ion Selective Electrodes, Mohr Titration, and Test Strips  

Microsoft Academic Search

\\u000a Sodium content of foods can be determined by various methods, including an ion selective electrode (ISE), the Mohr or Volhard\\u000a titration procedure, or indicator test strips. These methods are official methods of analysis for numerous specific products.\\u000a All these methods are faster and less expensive procedures than analysis by atomic absorption spectroscopy or inductively\\u000a coupled plasma-atomic emission spectroscopy. This experiment

S. Suzanne Nielsen

2010-01-01

105

Coulometrische titration von hypochloriten und chloraten.  

PubMed

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

Gründler, P; Holzapfel, H

1970-03-01

106

CCD Observations in the Vilnius Photometric System  

NASA Astrophysics Data System (ADS)

Setting up the Vilnius photometric system with CCD detectors is extremely important for investigation of galactic structure since the system makes it possible to determine completely by photometric means spectral classes, absolute magnitudes, metallicities and peculiarity types of stars, even when affected by interstellar reddening. The paper describes the first observations made in the Vilnius system with CCD detectors at the Kitt Peak National Observatory and the US Naval Observatory Flagstaff Station. The paper also describes available software for the photometric classification of stars and investigations planned with the VATT telescope on Mt. Graham in Arizona. Some recommendations for users of CCD cameras for stellar photometry are given.

Boyle, R. P.; Vrba, F. J.; Smriglio, F.; Dasgupta, A. K.; Straizys, V.

107

Estimating the redshift distribution of photometric galaxy samples - II. Applications and tests of a new method  

NASA Astrophysics Data System (ADS)

In Lima et al. we presented a new method for estimating the redshift distribution, N(z), of a photometric galaxy sample, using photometric observables and weighted sampling from a spectroscopic subsample of the data. In this paper, we extend this method and explore various applications of it, using both simulations and real data from the Sloan Digital Sky Survey (SDSS). In addition to estimating the redshift distribution for an entire sample, the weighting method enables accurate estimates of the redshift probability distribution, p(z), for each galaxy in a photometric sample. Use of p(z) in cosmological analyses can substantially reduce biases associated with traditional photometric redshifts, in which a single redshift estimate is associated with each galaxy. The weighting procedure also naturally indicates which galaxies in the photometric sample are expected to have accurate redshift estimates, namely those that lie in regions of photometric-observable space that are well sampled by the spectroscopic subsample. In addition to providing a method that has some advantages over standard photo-z estimates, the weights method can also be used in conjunction with photo-z estimates e.g. by providing improved estimation of N(z) via deconvolution of N(zphot) and improved estimates of photo-z scatter and bias. We present a publicly available p(z) catalogue for ~78 million SDSS DR7 galaxies.

Cunha, Carlos E.; Lima, Marcos; Oyaizu, Hiroaki; Frieman, Joshua; Lin, Huan

2009-07-01

108

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…

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

2011-01-01

109

Photometric Studies of GEO Debris  

NASA Astrophysics Data System (ADS)

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 Michigans 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? 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. We will compare our observations with models and laboratory measurements of selected surfaces. This work is supported by NASAs Orbital Debris Program Office, Johnson Space Center, and Houston, Texas, USA.

Seitzer, P.; Rodriguez-Cowardin, H.; Barker, E.; Abercromby, K.; Foreman, G.; Horstman M.

110

Comparison of Conductimetric and Colorimetric Methods with Distillation-Titration Method of Analyzing Ammonium-Nitrogen in Total Kjeldahl Digests  

Microsoft Academic Search

The distillation-titration method (DTM) is a standard procedure used by most laboratories to measure ammonium (NH4)- nitrogen (N) in the Total Kjeldahl Nitrogen (TKN) digests of various kinds of agricultural and environmental samples. These samples may have TKN contents ranging from less than 100 ppb to as high as percent level. However, the DTM procedure generally leads to a very

Uttam K. Saha; Leticia Sonon; David E. Kissel

2012-01-01

111

SSB binding to ssDNA using isothermal titration calorimetry.  

PubMed

Isothermal titration calorimetry (ITC) is a powerful method for studying protein-DNA interactions in solution. As long as binding is accompanied by an appreciable enthalpy change, ITC studies can yield quantitative information on stoichiometries, binding energetics (affinity, binding enthalpy and entropy) and potential site-site interactions (cooperativity). This can provide a full thermodynamic description of an interacting system which is necessary to understand the stability and specificity of protein-DNA interactions and to correlate the activities or functions of different species. Here we describe procedures to perform and analyze ITC studies using as examples, the E. coli SSB (homotetramer with 4 OB-folds) and D. radiodurans SSB (homodimer with 4 OB-folds). For oligomeric protein systems such as these, we emphasize the need to be aware of the likelihood that solution conditions will influence not only the affinity and enthalpy of binding but also the mode by which the SSB oligomer binds ssDNA. PMID:22976176

Kozlov, Alexander G; Lohman, Timothy M

2012-01-01

112

Photometric and Astrometric Calibration of the {JWST} Instrument Complement  

Microsoft Academic Search

In preparation for the James Webb Space Telescope, a set of cross calibration programs with HST and SPITZER for suitable primary photometric standards and astrometric fields was developed. NICMOS\\/HST and IRAC\\/SPITZER photometric observations of new solar analog standards in NGC 6791 and Melotte 66 were executed. These new photometric standards will provide ˜ 5% photometric precision at V˜ 19 from

R. I. Diaz-Miller

2007-01-01

113

International Intercomparisons of Photometric Base Units,  

National Technical Information Service (NTIS)

In order to evaluate the worldwide consistency of practical implementations of 1979 redifinition of the candela, the Consultative Committee for Photometry and Radiometry (CCPR) has conducted an international intercomparison of photometric base units. The ...

K. D. Mielenz

1987-01-01

114

Albedo Recovery Using a Photometric Stereo Approach  

Microsoft Academic Search

This paper describes a method for the estimation of surface reflectance values using a photometric stereo approach. Evaluations show that surfaces rendered with reflectance values calculated by the proposed method have more realistic appearances than those with constant albedo.

Chia-yen Chen; Reinhard Klette; Ramakrishna Kakarala

2002-01-01

115

Photometric Redshifts Using Boosted Decision Trees  

NASA Astrophysics Data System (ADS)

Precision photometric redshifts will be essential for extracting cosmological parameters from the next generation of wide-area surveys. I describe a new photometric redshift algorithm based on the machine-learning technique of Boosted Decision Trees (BDTs). The performance of the algorithm is evaluated using data from the Sloan Digital Sky Survey as well as a mock catalog intended to simulate the sensitivity of the upcoming Dark Energy Survey, and compared to the performance of existing photometric redshift estimators. I describe how redshift errors and the fraction of catastrophic failures are estimated. I also show that the inclusion of shape information along with the photometric data significantly improves the redshift determination of highly-inclined spiral galaxies.

Gerdes, David W.

2009-01-01

116

An Application of the Photometric Stereo Method.  

National Technical Information Service (NTIS)

The orientation of patches on the surface of an object can be determined from multiple images taken with different illumination, but from the same viewing position. This method, referred to as photometric stereo, can be implemented using table lookup base...

K. Ikeuchi B. K. P. Horn

1979-01-01

117

Photometric analysis of DO cassiopeiae  

NASA Astrophysics Data System (ADS)

New photoelectric observations of DO Cas in B and V were obtained in 1984 with the 35 centimeter reflector of Yunnan Observatory. A total of 583 individual observations in blue, and 590 individual observatirons in yellow were secured during 7 nights. An extensive search for a reliable mass ratio, q was carried out using the Wilson and Devinney method. Our q value of 0.397 is close to the value of 0.44 publislied by Cester et al. (1977) using Wood's method. Our solutions show that DO Cas is a semidetached system with the more massive primary component filling its Roche lobe. ?olute dimensions were determined by combining Mannino's spectroscopie results with the present photometric results. The radii of the components were found to be considerably larger than the ZAMS radii for the corresonding masses. Change of the period of DO Cas is found to alternate in sign with a period about 25 years. We concluded that DO Cas is a binary in which mass flows from the more massive primary to the secondary.

Liu, Qing-yao; Zhang, Yun-lin; Zhang, Zhou-sheng

1988-09-01

118

Photometric Study of Uranian Satellites  

NASA Astrophysics Data System (ADS)

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

Kesten, Philip R.

1998-10-01

119

Photometric stereo via expectation maximization.  

PubMed

This paper presents a robust and automatic approach to photometric stereo, where the two main components, namely surface normals and visible surfaces, are respectively optimized by Expectation Maximization (EM). A dense set of input images is conveniently captured using a digital video camera while a handheld spotlight is being moved around the target object and a small mirror sphere. In our approach, the inherently complex optimization problem is simplified into a two-step optimization, where EM is employed in each step: 1) Using the dense input, the weight or importance of each observation is alternately optimized with the normal and albedo at each pixel and 2) using the optimized normals and employing the Markov Random Fields (MRFs), surface integrabilities and discontinuities are alternately optimized in visible surface reconstruction. Our mathematical derivation gives simple updating rules for the EM algorithms, leading to a stable, practical, and parameter-free implementation that is very robust even in the presence of complex geometry, shadows, highlight, and transparency. We present high-quality results on normal and visible surface reconstruction, where fine geometric details are automatically recovered by our method. PMID:20075477

Wu, Tai-Pang; Tang, Chi-Keung

2010-03-01

120

Shape from Photometric Stereo and Contours  

Microsoft Academic Search

\\u000a In this work, we propose an alternative approach to 3D shape recovery by combining photometric stereo and shape from contours\\u000a methods. Surfaces recovered by photometric stereo are aligned, adjusted and merged according to a preliminary 3D model obtained\\u000a by shape from contours. Comparisons are conducted to evaluate the performances of different methods. It has been found that\\u000a the proposed approach

Chia-yen Chen; Reinhard Klette; Chi-fa Chen

2003-01-01

121

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

PubMed Central

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 primary dependent measure. After establishing stable performance in pigeons, several behaviorally-effective doses of cocaine were administered acutely. Dose-related within-session decreases in titrated delay values were observed. Following acute determinations, the dose of cocaine that produced the most rapid decline without eliminating performance was administered prior to each daily session. Chronic administration resulted in performance trending toward control levels. A redetermination of the dose–response function following chronic exposure revealed reduced potency (i.e., tolerance) under cocaine on titrated delay matching-to-sample performance. Supplemental analyses suggest that cocaine may serve as a disruptor of the stimulus conditions in which the performance was established.

Kangas, Brian D; Branch, Marc N

2012-01-01

122

A simple miniaturised photometrical method for rapid determination of nitrate and nitrite in freshwater  

Microsoft Academic Search

A rapid, simple miniaturised photometrical method was developed for the determination of nitrate and\\/or nitrite in freshwater samples. All procedures, including sample buffering, reduction by copperised cadmium granules, colour development and absorbance determination, were completed in a 96-well microplate. The factors governing the nitrate reduction and its recovery were investigated in detail, and the optimised analysing conditions were established. Nitrate

Xinhai Tu; Bangding Xiao; Jian Xiong; Xudong Chen

2010-01-01

123

Determining enzyme kinetics via isothermal titration calorimetry.  

PubMed

Isothermal titration calorimetry (ITC) has emerged as a powerful tool for determining the thermodynamic properties of chemical or physical equilibria such as protein-protein, ligand-receptor, and protein-DNA binding interactions. The utility of ITC for determining kinetic information, however, has not been fully recognized. Methods for collecting and analyzing data on enzyme kinetics are discussed here. The step-by-step process of converting the raw heat output rate into the kinetic parameters of the Michaelis-Menten equation is explicitly stated. The hydrolysis of sucrose by invertase is used to demonstrate the capability of the instrument and method. PMID:23423886

Demarse, Neil A; Killian, Marie C; Hansen, Lee D; Quinn, Colette F

2013-01-01

124

Three-dimensional stereo by photometric ratios  

SciTech Connect

We present a methodology for corresponding a dense set of points on an object surface from photometric values for three-dimensional stereo computation of depth. The methodology utilizes multiple stereo pairs of images, with each stereo pair being taken of the identical scene but under different illumination. With just two stereo pairs of images taken under two different illumination conditions, a stereo pair of ratio images can be produced, one for the ratio of left-hand images and one for the ratio of right-hand images. We demonstrate how the photometric ratios composing these images can be used for accurate correspondence of object points. Object points having the same photometric ratio with respect to two different illumination conditions constitute a well-defined equivalence class of physical constraints defined by local surface orientation relative to illumination conditions. We formally show that for diffuse reflection the photometric ratio is invariant to varying camera characteristics, surface albedo, and viewpoint and that therefore the same photometric ratio in both images of a stereo pair implies the same equivalence class of physical constraints. The correspondence of photometric ratios along epipolar lines in a stereo pair of images under different illumination conditions is a correspondence of equivalent physical constraints, and the determination of depth from stereo can be performed. Whereas illumination planning is required, our photometric-based stereo methodology does not require knowledge of illumination conditions in the actual computation of three-dimensional depth and is applicable to perspective views. This technique extends the stereo determination of three-dimensional depth to smooth featureless surfaces without the use of precisely calibrated lighting. We demonstrate experimental depth maps from a dense set of points on smooth objects of known ground-truth shape, determined to within 1% depth accuracy.

Wolff, L.B.; Angelopoulou, E. [Computer Vision Laboratory, Department of Computer Science, The Johns Hopkins University, Baltimore, Maryland 21218 (United States)

1994-11-01

125

PHOTOMETRIC ORBITS OF EXTRASOLAR PLANETS  

SciTech Connect

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

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

2009-09-10

126

Potentiometric titration of chloride in plant tissue extracts using the chloride ion electrode  

Microsoft Academic Search

Use of the chloride specific ion electrode to determine chloride in plants was evaluted. Direct potentiometric determination of chloride by the electrode resulted in unreproducible and extremely high chloride values. However, use of this electrode to indicate the end point in titration of the tissue?extract mixture with AgNO3 gave results nearly identical to those obtained by the Mohr procedure. The

R. L. LaCroix; D. R. Keeney; L. M. Walsh

1970-01-01

127

New chemical titration proposed for potassium mud testing  

SciTech Connect

An accurate and easy-to-use procedure for measuring the potassium ion concentration in drilling and completion fluids has been developed and successfully used in Union Oil Co. of California's drilling operations. This volumetric analysis is based on the quantitative conversion of soluble sodium tetraphenylboron to the insoluble potassium tetraphenylboron and back titration with a quaternary ammonium salt in the presence of Titan yellow (Clayton yellow) indicator. This gives an easy-to-read color change endpoint from milky white to intense pink. The procedure described here is as fast as flame emission analysis and as accurate as the gravimetric analysis. This method has been used for several years in the fertilizer industry with success, but is new to drilling operations, at least in this revised form. This method, adapted from the potash industry, is easier and more accurate than other methods. Results compare favorably (within 3%) with flame emision or atomic absorption methods. The NaTPB method is proposed as a replacement for the method described in API RP 13B.

Zilch, H.E.

1984-01-01

128

Automated titration method for use on blended asphalts  

SciTech Connect

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

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

2012-08-07

129

On the invention of conductimetric titration.  

PubMed

In contrast to the earlier statement of one of the authors according to which conductimetric titration was invented by Küster and Grüters in 1903, it is shown that Ostwald made use of this analytical method as early as the nineties of the past century. Prior to Ostwald's work, however, papers appeared in which conductimetric curves were shown, with statements about their different characteristics in the case of reaction between weak and strong acids and bases. The first of these seems to be due to Kohlrausch [together with one of his co-workers, Kreichgauer (1885)]. It does not seem to have occurred to them, however, to use this phenomenon for the purposes of analytical chemistry, namely for titrimetry. PMID:18963516

Szabadváry, F; Chalmers, R A

1983-12-01

130

Computational titrations of linear and branched polyethyleneimine  

NASA Astrophysics Data System (ADS)

Despite a great deal of interest in polyethyleneimine (PEI) for its potential use as a gene therapy vector, the protonation state of this polycation is currently not well understood. PEI is rare among polyelectrolytes as every third atom along the backbone of the polymer is a protonable nitrogen. The closeness of these potentially charged sites can lead to high electrostatic repulsion and a large shift in the effective pKa of the amine groups as the degree of protonation increases. Previous experimental and theoretical estimates of the degree of protonation of PEI under physiological conditions have ranged from 0.15 to 0.80. Here, we perform computational titrations on coarse-grained models of both branched and linear PEI under various conditions. Chain length, degree of branching, salt concentration, and the solvent dielectric constant are varied to determine how these factors influence the protonation of PEI.

Ziebarth, Jesse; Wang, Yongmei

2009-03-01

131

Photometric and geometric rectification for stereoscopic images  

NASA Astrophysics Data System (ADS)

Stereoscopic images are captured by two cameras at different positions. In general, the two images often have geometric distortions including vertical misalignment, rotation and keystone as well as photometric distortions such as luminance or color differences. Even in case of a carefully designed parallel stereo camera configuration, the captured images pairs may have the distortions that cause uncomfortable 3D experiences to users. In this paper, we develop an algorithm to correct the captured image pairs to give a comfortable stereoscopic experience to users. The algorithm provides a practical method for compensating the photometric and geometrical distortions.

Han, Seung-Ryong; Min, Jongsul; Park, Taesung; Kim, Yongje

2012-02-01

132

Philosophy and Updating of the Asteroid Photometric Catalogue.  

National Technical Information Service (NTIS)

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

P. Magnusson M. A. Barucci M. T. Capria M. Dahlgren M. Fulchignoni

1992-01-01

133

P32Tools: testing the photometric calibration  

NASA Astrophysics Data System (ADS)

Results of tests to assess the photometric calibration of maps obtained with the P32Tools package are presented. The effect of P32Tools on the source flux calibration of a compact source was investigated on the galaxy UGC 89. The possible changes in surface brightness calibration were tested towards the ex- tended source LMC1.

Laureijs, R. J.

2002-12-01

134

P32Tools: testing the photometric calibration  

Microsoft Academic Search

Results of tests to assess the photometric calibration of maps obtained with the P32Tools package are presented. The effect of P32Tools on the source flux calibration of a compact source was investigated on the galaxy UGC 89. The possible changes in surface brightness calibration were tested towards the ex- tended source LMC1.

R. J. Laureijs

2002-01-01

135

On Photometric Aspects of Catadioptric Cameras  

Microsoft Academic Search

Several imaging systems called catadioptric cameras have been developed that use a combination of lenses and mirrors to obtain wide fields of view. Geometric aspects have been well studied. This paper focuses on photometric aspects of catadioptric cameras. We discuss how geometric distortion of images of catadioptric cameras resulting from curvature of the mirror affects image irradiance. We show that

Takayuki Okatani; Koichiro Deguchi

2001-01-01

136

The WFPC2 Photometric CTE Monitor  

Microsoft Academic Search

The Charge Transfer Efficiency of the WFPC2 CCD arrays has been monitored since the instrument's deployment aboard HST in 1993. Since then a significant increase in CTE loss has been observed. We examine photometric data from 28 April 1994 to 11 February 2001. The CTE loss appears to be growing worse in a linear fashion with time. The results from

Inge Heyer

2001-01-01

137

THE Pan-STARRS1 PHOTOMETRIC SYSTEM  

SciTech Connect

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

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

2012-05-10

138

Photometric Deprojection of Edge-on Galaxies  

NASA Astrophysics Data System (ADS)

Photometric deprojection is used to determine the stellar-disk and bulge parameters for several edge-on galaxies from the FGC catalog. The assumption that the galaxies of our sample belonging to the fourth (i.e., lowest) surface-brightness class in the FGC are edge-on, low-surface-brightness (LSB) galaxies is considered.

Bizyaev, D. V.

2000-04-01

139

Using a Raster Display for Photometric Stereo  

Microsoft Academic Search

This paper presents a new controlled lighting apparatus which uses a raster display device as a light source. The setup has the advantage over other alternatives in that it is relatively inexpensive and uses commonly available com- ponents. The apparatus is studied through application to shape recovery using photometric stereo. Experiments on synthetic and real images demonstrate how the depth

Nathan Funk; Yee-hong Yang

2007-01-01

140

Shape from Photometric Ratio and Stereo  

Microsoft Academic Search

Based on the traditional problem formulation, it is difficult to integrate the two important vision cues, i.e., shading and stereo, for shape reconstruction due to conflicting albedo and image projection assumptions. In this research, we propose a novel scheme to integrate shading and stereo. First, by using the photometric ratio, we derive a new SFS (shape from shading) formulation where

Kyoung Mu Lee; C.-C. Jay Kuo

1996-01-01

141

Can Two Specular Pixels Calibrate Photometric Stereo?  

Microsoft Academic Search

Lambertian photometric stereo with unknown light source parameters is ambiguous. Provided that the object imaged constitutes a surface, the ambiguity is represented by the group of Generalised Bas-Relief (GBR) transformations. We show that this ambiguity is resolved when specular re- flection is present in two images taken under two different light source directions. We identify all configurations of the two

Ondrej Drbohlav; Mike J. Chantler

2005-01-01

142

A new approach to photometric stereo  

Microsoft Academic Search

We introduce a new approach to shape estimation from photometric stereo images. The input images are matched through an optical flow algorithm, with the matching direction iteratively refined. The resulting disparity field is then used in a structure-from-motion reconstruction which does not require reflectance map information.

José R. A. Torreão

1999-01-01

143

On Optimal Light Configurations in Photometric Stereo  

Microsoft Academic Search

This paper develops new theory for the optimal placement of photometric stereo lighting in the presence of camera noise. We show that for three lights, any triplet of orthog- onal light directions minimises the uncertainty in scaled normal computation. The assumptions are that the camera noise is additive and normally distributed, and uncertainty is defined as the expectation of squared

Ondrej Drbohlav; Mike J. Chantler

2005-01-01

144

HRSC Topographic Correction by Minnaert Photometric Modeling  

NASA Astrophysics Data System (ADS)

In a systematic approach, we want to use the exact orientation information of an image sequence of the High Resolution Stereo Camera (HRSC, [1], [2]) to derive a synthetic photometric model and compare it with the recorded HRSC image. This model can serve for several purposes, one of which would be the isolation of albedo features from the topographic shading effects.

Walter, S.; Kirk, R.; McGuire, P. C.; Neukum, G.

2011-10-01

145

Illumination Invariant Face Recognition Using Photometric Stereo  

Microsoft Academic Search

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

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

1998-01-01

146

Photometric stereo using point light sources  

Microsoft Academic Search

Practical lamps for undersea illumination are closely approximated by point sources, the light from which diverges and also attenuates due to scattering and absorption by the water. The objective is to determine the error introduced by these departures from the usual lighting assumptions of photometric stereo and to find an approach to solution of the brightness equations. It is demonstrated

Nagesh Kolagani; Joel S. Fox; D. Richard Blidberg

1992-01-01

147

Two-image photometric stereo method  

Microsoft Academic Search

In the photometric stereo method, the surface orientation of an object is determined by using multiple images (at least three images). The multiple images are obtained by changing the position of a light source, and the surface orientation of the object can be determined only in the area of the object illuminated by all light sources. So it is desirable

Jun Yang; Noboru Ohnishi; Noboru Sugie

1992-01-01

148

Specularities Reduce Ambiguity of Uncalibrated Photometric Stereo  

Microsoft Academic Search

Lambertian photometric stereo with uncalibrated light directionsand intensities determines the surface normals only up to aninvertible linear transformation. We show that if object reflectance isa sum of Lambertian and specular terms, the ambiguity reduces into a2dof group of transformations (compositions of isotropic scaling, rotationaround the viewing vector, and change in coordinate frame handedness).

Ondrej Drbohlav; Radim Sára

2002-01-01

149

New Photometric Observations of RS Oph  

NASA Astrophysics Data System (ADS)

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

Voloshina, Irina; Metlov, Vladimir

2013-01-01

150

Titration of cyanide and hexacyanoferrate(II) with silver nitrate-I Calculation of titration curves for potentiometric and conductometric titration.  

PubMed

Stepwise potentiometric titration of cyanide and hexacyanoferrate(II) with silver nitrate is possible in the absence of potassium ions. At an initial concentration below 5.00 x 10(-4)M, cyanide can be titrated with silver nitrate (Ag:CN = 1:2) and the end-point indicated by precipitation of silver hexacyanoferrate(II); hexacyanoferrate(II) can be titrated with silver nitrate (Ag: Fe(CN)(6) = 4:1) and the end-point indicated by precipitation of silver dicyanoargentate. The hexacyanoferrate(II) reacts with silver to form two poorly soluble salts, Ag(4)Fe(CN)(6), KAg(3)Fe(CN)(6). The formation of these salts has been confirmed by conductometric titration of hexacyanoferrate(II) with silver nitrate in solutions containing varying concentrations of potassium nitrate. PMID:18962224

Asplund, J

1978-03-01

151

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

152

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

153

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

154

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

155

Potentiometric Acid-Base Titrations with Activated Graphite Electrodes  

NASA Astrophysics Data System (ADS)

Dry cell graphite (DCG) electrodes activated with potassium permanganate are employed as potentiometric indicator electrodes for acid-base titrations. Special attention is given to an indicator probe comprising activated DCG-non-activiated DCG electrode couple. This combination also proves suitable for the titration of strong or weak acids.

Riyazuddin, P.; Devika, D.

1997-10-01

156

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

157

Optimal Filter Systems for Photometric Redshift Estimation  

NASA Astrophysics Data System (ADS)

In the coming years, several cosmological surveys will rely on imaging data to estimate the redshift of galaxies, using traditional filter systems with 4-5 optical broad bands; narrower filters improve the spectral resolution, but strongly reduce the total system throughput. We explore how photometric redshift performance depends on the number of filters nf , characterizing the survey depth by the fraction of galaxies with unambiguous redshift estimates. For a combination of total exposure time and telescope imaging area of 270 hr m2, 4-5 filter systems perform significantly worse, both in completeness depth and precision, than systems with nf gsim 8 filters. Our results suggest that for low nf the color-redshift degeneracies overwhelm the improvements in photometric depth, and that even at higher nf the effective photometric redshift depth decreases much more slowly with filter width than naively expected from the reduction in the signal-to-noise ratio. Adding near-IR observations improves the performance of low-nf systems, but still the system which maximizes the photometric redshift completeness is formed by nine filters with logarithmically increasing bandwidth (constant resolution) and half-band overlap, reaching ~0.7 mag deeper, with 10% better redshift precision, than 4-5 filter systems. A system with 20 constant-width, nonoverlapping filters reaches only ~0.1 mag shallower than 4-5 filter systems, but has a precision almost three times better, ?z = 0.014(1 + z) versus ?z = 0.042(1 + z). We briefly discuss a practical implementation of such a photometric system: the ALHAMBRA Survey.

Benítez, N.; Moles, M.; Aguerri, J. A. L.; Alfaro, E.; Broadhurst, T.; Cabrera-Caño, J.; Castander, F. J.; Cepa, J.; Cerviño, M.; Cristóbal-Hornillos, D.; Fernández-Soto, A.; González Delgado, R. M.; Infante, L.; Márquez, I.; Martínez, V. J.; Masegosa, J.; Del Olmo, A.; Perea, J.; Prada, F.; Quintana, J. M.; Sánchez, S. F.

2009-02-01

158

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

159

Direct photometric determination of fluorides in potassium chloride and iodide  

SciTech Connect

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

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

1985-05-01

160

Processing Photometric Full-Disk Solar Images  

NASA Astrophysics Data System (ADS)

The Cartesian Full Disk Telescopes (CFDTs) at the San Fernando Observatory (SFO) produce daily full-disk digital solar images using a linear Reticon diode array scanned by the Earth's rotation. In this paper, we describe in some detail the data processing techniques used to extract photometric information from CFDT images. We believe our experience in this field will be found useful by other workers as more instruments are built and operated with similar scientific goals to the CFDT. We describe: 1. our photometric calibration techniques and accuracy; 2. the method we use to identify the position of the limb; 3. production of a contrast map from the image, including finding a mean limb darkening curve; 4. identification of solar features. Preprints of a paper giving all algorithms in detail will be available at the meeting. This research has been supported by NASA grant NAGW-3017 and NSF grant ATM-9504374.

Walton, S. R.; Chapman, G. A.; Cookson, A. M.; Dobias, J. J.; Preminger, D. G.

1997-05-01

161

RATS: the photometric data reduction automatic pipeline  

NASA Astrophysics Data System (ADS)

The automatic photometric pipeline provides a real time images reduction and directly the light curves of object in the field within the RATS project (RAdial Velocities Transit Search). The light curves themselves will be analyzed in order to catch light dimming due to a transit. For this purpose, the algorithm needs as input files a list of fits images taken at Schmidt Telescope of Asiago (INAF, Italy), a reference master list of stars and three files with the optional parameters for the DAOPHOT photometry package (Stetson 1987, PASP, 99, 191). The master list is previously obtained from a photometric characterization of the field (for more details: http://www.rats.it and Claudi et al. 2006, in Observatoire de Haute Provence Colloquium, Tenth Anniversary of 51 Peg-b: Status of and prospects for hot Jupiter studies, 22-25 August 2005, eds. Arnold, L., Bouchy, F. and Moutou, C., 350).

Granata, V.; Montalto, M.; Contri, L.; Claudi, R.; Piotto, G.

2006-02-01

162

Overcoming shadows in 3-source photometric stereo.  

PubMed

Light occlusions are one of the most significant difficulties of photometric stereo methods. When three or more images are available without occlusion, the local surface orientation is overdetermined so that shape can be computed and the shadowed pixels can be discarded. In this paper, we look at the challenging case when only two images are available without occlusion, leading to a one degree of freedom ambiguity per pixel in the local orientation. We show that, in the presence of noise, integrability alone cannot resolve this ambiguity and reconstruct the geometry in the shadowed regions. As the problem is ill-posed in the presence of noise, we describe two regularization schemes that improve the numerical performance of the algorithm while preserving the data. Finally, the paper describes how this theory applies in the framework of color photometric stereo where one is restricted to only three images and light occlusions are common. Experiments on synthetic and real image sequences are presented. PMID:20921582

Hernández, Carlos; Vogiatzis, George; Cipolla, Roberto

2011-02-01

163

Stellar physics with the ALHAMBRA photometric system  

NASA Astrophysics Data System (ADS)

The ALHAMBRA photometric system was specifically designed to perform a tomography of the Universe in some selected areas. Although mainly designed for extragalactic purposes, its 20 contiguous, equal-width, medium-band photometric system in the optical wavelength range, shows a great capacity for stellar classification. In this contribution we propose a methodology for stellar classification and physical parameter estimation (Teff, log g, [Fe/H], and color excess E(B - V)) based on 18 independent reddening-free Q-values from the ALHAMBRA photometry. Based on the theoretical Spectral library BaSeL 2.2, and applied to 288 stars from the Next Generation spectral Library (NGSL), we discuss the reliability of the method and its dependence on the extinction law used.

Aparicio Villegas, T.; Alfaro, E. J.; Cabrera-Caño, J.; Moles, M.; Benítez, N.; Perea, J.; del Olmo, A.; Fernández-Soto, A.; Cristóbal-Hornillos, D.; Aguerri, J. A. L.; Broadhurst, T.; Castander, F. J.; Cepa, J.; Cervio, M.; González Delgado, R. M.; Infante, L.; Márquez, I.; Masegosa, J.; Martínez, V. J.; Prada, F.; Quintana, J. M.; Sánchez, S. F.

2011-12-01

164

Antidepressant up-titration: pharmacological and psychological considerations.  

PubMed

The use of antidepressant up-titration in starting therapies is useful in reducing side effects, but can induce delays in clinical response. Several aspects concerning slow or more aggressive titration have to be considered when using this strategy, such as pharmacological aspects (e.g., synaptic up-regulation) and psychological/clinical aspects (e.g., adherence to antidepressant treatment, and the temperament and expectations of patients). Data from the literature are controversial, and so the choice between rapid and slow titration must be tailored more to the patient, rather than to the drug. PMID:22862155

Torta, Riccardo G V

2012-08-06

165

A test of the Hapke photometric model  

NASA Astrophysics Data System (ADS)

We conducted a test of the Hapke (1981, 1984, 1986, 2002) photometric model to determine what physical parameters could be confidently linked to a surface's photometric behavior. The first author selected and measured the bidirectional reflectance distribution functions of 14 different samples in up to three different wavelengths using the Bloomsburg University Goniometer Laboratory. A total of 29 data files were obtained, each file containing more than 700 measurements from different viewing geometries; phase angles varied from 3° to 130°. The 29 files were initially sent ``in-the-blind'' to the second author, who was charged with inverting the data files and extracting best fit model parameters. Our baseline model used the most recent Hapke (2002) formulation with a two-term Henyey-Greenstein particle phase function and shadow-hiding backscatter opposition effect (SHOE) model. We also inverted the data with three other variations that included three-term Henyey-Greenstein phase functions and both SHOE and the coherent backscatter opposition effect (CBOE) models. Our results were compared with the known physical properties of our samples. We found no compelling evidence that individual photometric parameters could be uniquely interpreted to reveal the physical state of our samples, either in an absolute or relative sense. Rather, combinations of physical properties such as albedo, roughness, and porosity were convolved within each retrieved photometric parameter. On the basis of our empirical evidence, we speculate that the fault lies with the inability of radiative transfer models to adequately account for discrete media and the effects of porosity, and its deficient assumption that individual particles are the primary scattering units.

Shepard, Michael K.; Helfenstein, Paul

2007-03-01

166

Photometric Redshifts of Galaxies in COSMOS  

Microsoft Academic Search

We present photometric redshifts for the COSMOS survey derived from a new code, optimized to yield accurate and reliable redshifts and spectral types of galaxies down to faint magnitudes and redshifts out to z~1.2. The technique uses chi2 template fitting, combined with luminosity function priors and with the option to estimate the internal extinction [or E(B-V)]. The median most probable

B. Mobasher; P. Capak; N. Z. Scoville; T. Dahlen; M. Salvato; H. Aussel; D. J. Thompson; R. Feldmann; L. Tasca; O. Le Fevre; S. Lilly; C. M. Carollo; J. S. Kartaltepe; H. McCracken; J. Mould; A. Renzini; D. B. Sanders; P. L. Shopbell; Y. Taniguchi; M. Ajiki; Y. Shioya; T. Contini; M. Giavalisco; O. Ilbert; A. Iovino; V. Le Brun; V. Mainieri; M. Mignoli; M. Scodeggio

2007-01-01

167

Shape from Shading and Photometric Stereo Methods  

Microsoft Academic Search

This TR is a review of shading based shape recovery (shape from shading, photometricstereo methods). It reports about advances in appliedwork and about results intheoretical fundamentals.1CITR, Tamaki Campus, University Of Auckland, Auckland, New Zealand2Computer Science Department, University of Western Australia, Perth, Australia3Pathology Institute, Charite, Humboldt University, Berlin, GermanyShape from Shading and Photometric StereoMethodsReinhard KletteThe University of...

Reinhard Klette; Ryszard Kozera; Karsten Schlüns

1998-01-01

168

Shadows in Three-Source Photometric Stereo  

Microsoft Academic Search

Shadows are one of the most significant difficulties of the photometric stereo method. When four or more images are available,\\u000a local surface orientation is overdetermined and the shadowed pixels can be discarded. In this paper we look at the challenging\\u000a case when only three images under three different illuminations are available. In this case, when one of the three pixel

Carlos Hernández; George Vogiatzis; Roberto Cipolla

2008-01-01

169

In vivo photometric analysis of hemoglobin  

Microsoft Academic Search

Since virtually all the oxygen carried by blood at normal hematocrit is reversibly bound to red blood cell hemoglobin, the\\u000a distribution of oxygen within the microcirculation can be determined from measurements of hemoglobin concentration and hemoglobin\\u000a oxygen saturation in vessels of the network. Photometric methods that rely on light absorption and scattering properties of\\u000a blood are described. Criteria for selecting

Roland N. Pittman

1986-01-01

170

Photometric assessment of energy efficient torchieres  

SciTech Connect

Extensive development of designs and prototyping of energy efficient torchiere systems using compact fluorescent lamps (CFLs) has led directly to the production of CFL torchieres by a major US manufacturer. This paper compares the electrical and photometric characteristics of one of the new CFL torchieres to standard tungsten halogen torchieres (halogen uplighters). Power assessments and gonio-photometric data indicate that the new CFL torchiere provides significant energy savings over the standard tungsten halogen torchiere while producing more luminous flux. The energy savings is jointly due to the high source efficacy of the CFLs and the poor performance . of the imported halogen lamps. The paper also presents results from a test site in the student dormitories at Stanford University where a torchiere "lamp swap" program was initiated in which students voluntarily traded their halogen torchieres for CFL torchieres. Out of the 500 torchieres involved in the lamp swap, a random sample of nearly 100 halogen lamps (seasoned in the field and considered to represent a typical population) were collected and photometrically and electrically characterized in the laboratory. These laboratory results indicate that the CFL torchieres use 65 watts to produce 25 percent more light than the 300 W tungsten halogen torchieres they are designed to replace. Additionally, the CFL torchieres have the benefit of a cooler lamp operating temperature, making them safer luminaires.

Page, Erik; Siminovitch, Michael

1997-06-01

171

White Dwarfs in the SDSS Photometric Footprint  

NASA Astrophysics Data System (ADS)

Attempts to create a homogeneous catalogue of white dwarfs have always been faced with the challenge posed by the intrinsic faintness of these objects. In recent years, thanks to large area surveys like the Sloan Digital Sky Survey (SDSS), the size of the known white dwarf population has increased dramatically, but, in order to carry out a statical study on the population of white dwarfs, it is necessary to have a reliable and well-defined selection method. We present a method which uses cuts in colour-colour space to select from DR7 16785 bright (g ? 19) photometric DA white dwarf candidates (Girven et al. 2011). The selection is 62% efficient in returning DA white dwarfs and produces a DA sample which is 95% complete for Teff > 8000 K. This sample contains 4636 spectroscopically confirmed DA white dwarfs; i.e. a ˜70% increase compared to Eisenstein et al.'s sample. As a first application of the SDSS DR7 DA candidates sample we cross correlated it with Data Release 8 of UKIDSS Large Area Survey with the aim of identifying white dwarfs which exhibit an infrared excess consistent with the presence of low mass stellar companions or dusty debris discs. Our current work aims to extend the photometric selection to all types of white dwarfs, using reduced proper motion as a further constrain. We expect to find a total of ˜20 000 photometric white dwarf candidates with g ? 19 in the footprint of SDSS DR8.

Gentile Fusillo, N. P.; Girven, J.; Gänsicke, B.

2013-01-01

172

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); Carr, M. [Princeton University Observatory, Princeton, NJ 08544 (United States); Rockosi, C. [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); 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); 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); Harris, F. [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); Doi, M. [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); 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); Okada, N. [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); Blouke, M.; Heidtman, D. [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); Lucinio, R.; and others

1998-12-01

173

Catalogue of Geneva Photometric Boxes (Nicolet, 1982)  

NASA Astrophysics Data System (ADS)

The Geneva photometric boxes, or Golay's boxes, are based on the Geneva 7-colour photometry contained in Rufener's 3rd Catalogue (Cat. II/72). For a given star S measured in the Geneva photometry, the strict [0.01] box is the set of stars S' whose colours are all equal to those of S within 0.01mag; S is called the central star, and the S' are the member stars of the [0.01] box of S. Only the boxes containing at least 2 elements (including S) are considered. Other definitions of the photometric boxes are used. For instance, the "0.01" box of S contains the stars S' having |dU|=|U(S)-U(S')}<=0.02, and all other colours |dV|, |dB1|, |dB2|, |dV1| and |dG| all <=0.01. Photometric boxes can also be defined from other colour indices (reddening-free), or with elliptical shapes. See the definitions used here in the "Note (G2)" section below. (3 data files).

Nicolet, B.

2013-03-01

174

Modified titrimetric determination of plutonium using photometric end-point detection  

SciTech Connect

A method used at LASL for the accurate and precise assay of plutonium metal was modified for the measurement of plutonium in plutonium oxides, nitrate solutions, and in other samples containing large quantities of plutonium in oxidized states higher than +3. In this modified method, the plutonium oxide or other sample is dissolved using the sealed-reflux dissolution method or other appropriate methods. Weighed aliquots, containing approximately 100 mg of plutonium, of the dissolved sample or plutonium nitrate solution are fumed to dryness with an HC1O/sub 4/-H/sub 2/SO/sub 4/ mixture. The dried residue is dissolved in dilute H/sub 2/SO/sub 4/, and the plutonium is reduced to plutonium (III) with zinc metal. The excess zinc metal is dissolved with HCl, and the solution is passed through a lead reductor column to ensure complete reduction of the plutonium to plutonium (III). The solution, with added ferroin indicator, is then titrated immediately with standardized ceric solution to a photometric end point. For the analysis of plutonium metal solutions, plutonium oxides, and nitrate solutions, the relative standard deviation are 0.06, 0.08, and 0.14%, respectively. Of the elements most likely to be found with the plutonium, only iron, neptunium, and uranium interfere. Small amounts of uranium and iron, which titrate quantitatively in the method, are determined by separate analytical methods, and suitable corrections are applied to the plutonium value. 4 tables, 4 figures.

Baughman, W.J.; Dahlby, J.W.

1980-04-01

175

Photometric properties of Vesta from Dawn  

NASA Astrophysics Data System (ADS)

The Dawn spacecraft collected visible images of Vesta through a wide-band clear filter and seven narrow-band color filters centered from 430 to 980 nm, and spectral cubes from 0.25 to 5 ?m. The phase angle coverage of the data is ~8° to ~108°, much larger than previously achieved from the ground. The minimum pixel size at Vesta is ~50 m for images, and ~120 m for spectral cubes. We report a preliminary analysis of the photometric properties of Vesta from Dawn data. Photometric properties of airless bodies, such as albedo, phase function, roughness, and opposition effects, are the fundamental properties determined by surface physical properties such as composition, regolith status, and geological processing. Photometric modeling removes the effect of topography from the apparent brightness of a surface under varying illumination and viewing geometries, and is critical for interpreting colors and spectral features of Vesta's surface. We analyzed the disk-integrated phase function of Vesta, and performed disk-resolved modeling with various models to study its global photometric properties and variations. The disk-integrated phase function of Vesta is similar to those of vestoids observed from the ground at phase angles lower than ~80°, but shows stronger forward scattering at higher phase angles. The brightness of Vesta is consistent with a visible geometric albedo of ~0.38, agreeing with previous measurements by IRAS. Hapke's modeling yields a visible single-scattering albedo of ~0.6, which is consistent with previous ground-based observations, and higher than most asteroids and the Moon. This high albedo might be due to smaller particle sizes, a fresher surface with less weathering, and/or mineral compositions. The globally averaged Hapke's roughness of Vesta is ~20°, independent of wavelength. The single-particle phase function of Vesta has relatively shallower slopes at longer wavelengths, consistent with phase reddening. Vesta's surface displays large variations in photometric properties, which are presumably related to compositional variations and geological processes. We note that these results are preliminary, and have to be thoroughly analyzed and tested at various size scales before reliable physical/mineralogical/geological interpretations can be made.

Li, J.; Buratti, B. J.; Schroeder, S.; Hicks, M.; Reddy, V.; Denevi, B. W.; Jorda, L.; Nathues, A.; Mottola, S.; Hoffmann, M.; Raymond, C. A.; Roatsch, T.; Russell, C. T.; Capaccioni, F.; Capria, M. T.; De Sanctis, M. C.; Filacchione, G.; Mastrodemos, N.; Pieters, C. M.; Sykes, M. V.; Titus, T. N.; Keller, H. U.; Dawn Science Team

2011-12-01

176

Microscope Titration and Extraction of DNA from Liver.  

ERIC Educational Resources Information Center

|Describes a simple and inexpensive, one-period activity to extract DNA to make the study of DNA less abstract. A microscope titration is used to determine when cells are ready for DNA extraction. (PR)|

Mayo, Lois T.; And Others

1993-01-01

177

Microscope Titration and Extraction of DNA from Liver.  

ERIC Educational Resources Information Center

Describes a simple and inexpensive, one-period activity to extract DNA to make the study of DNA less abstract. A microscope titration is used to determine when cells are ready for DNA extraction. (PR)

Mayo, Lois T.; And Others

1993-01-01

178

Zur potentiometrischen Titration von Phenolen in Gegenwart von Äthylenoxidaddukten  

Microsoft Academic Search

The potentiometric titration of phenols with sodium hydroxide solution has been made possible by addition of ethoxylated nonylphenol, as the dissociation constants of the complexes formed are considerably greater than those of the phenols.

K. H. Mohr; F. Wolf

1967-01-01

179

A Titration Technique for Demonstrating a Magma Replenishment Model.  

ERIC Educational Resources Information Center

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

Hodder, A. P. W.

1983-01-01

180

Cyclic alternating pattern and positive airway pressure titration  

Microsoft Academic Search

Objective: To demonstrate that stability of the upper airway during continuous positive airway pressure (CPAP) titration is influenced by the microstructure of sleep as defined by the cyclic alternating pattern (CAP).Methods: Retrospective review of 12 CPAP titration records. The patterns of flow-limitation during CPAP at subtherapeutic pressures were characterized as ‘stable’ (persistent and non-progressive inspiratory flow limitation) or ‘unstable’ (progressive

Robert Joseph Thomas

2002-01-01

181

Surface properties and modeling potentiometric titration of aqueous illite suspensions  

Microsoft Academic Search

The potentiometric titration behavior of complex illitic clay minerals provided from different origins (two Tunisian illite\\u000a samples and an American illite sample) was investigated and interpreted according to the surface complexation theory. In the\\u000a present investigation, the focus is on the surface charge characteristics. The proton surface charge can be calculated by\\u000a subtracting the supernatant titration curves from those of

A. Kriaa; N. Hamdi; E. Srasra

2008-01-01

182

Coulometric microflow titrations with chemiluminescent and amperometric equivalence point detection  

Microsoft Academic Search

A coulometric flow titration with electrogenerated bromine was combined with chemiluminescent and amperometric flow detection to determine low concentrations of hydrazine and ammonium. Hydrazine can be precisely titrated in the range between 2?M and 1.1mM with chemiluminescence detection of the equivalence points with relative standard deviations between 1.9 and 0.4% (n=5, ?=0.05). 60nM is the lowest concentration of hydrazine, which

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

2000-01-01

183

Ionization behavior of polyphosphoinositides determined via the preparation of pH titration curves using solid-state 31P NMR.  

PubMed

Detailed knowledge of the degree of ionization of lipid titratable groups is important for the evaluation of protein-lipid and lipid-lipid interactions. The degree of ionization is commonly evaluated by acid-base titration, but for lipids localized in a multicomponent membrane interface this is not a suitable technique. For phosphomonoester-containing lipids such as the polyphosphoinositides, phosphatidic acid, and ceramide-1-phosphate, this is more conveniently accomplished by (31)P NMR. Here, we describe a solid-state (31)P NMR procedure to construct pH titration curves to determine the degree of ionization of phosphomonoester groups in polyphosphoinositides. This procedure can also be used, with suitable sample preparation conditions, for other important signaling lipids. Access to a solid-state, i.e., magic angle spinning, capable NMR spectrometer is assumed. The procedures described here are valid for a Bruker instrument, but can be adapted for other spectrometers as needed. PMID:23681530

Graber, Zachary T; Kooijman, Edgar E

2013-01-01

184

Photometric and Astrometric Calibration of the JWST Instrument Complement  

Microsoft Academic Search

In preparation for James Webb Space Telescope (JWST), a set of cross\\u000acalibration programs with HST and Spitzer for suitable primary photometric\\u000astandards and astrometric fields were developed. NICMOS\\/HST and IRAC\\/Spitzer\\u000aphotometry observations of new solar analog standards in NGC 6791 and Melotte\\u000a66 were executed. These new photometric standards will provide ~ 5% photometric\\u000aprecision at V~19 from the

Rosa I. Diaz-Miller

2006-01-01

185

Photometric calibration of the Swift ultraviolet\\/optical telescope  

Microsoft Academic Search

We present the photometric calibration of the Swift Ultraviolet\\/Optical Telescope (UVOT) which includes: optimum photometric and background apertures, effective area curves, colour transformations, conversion factors for count rates to flux and the photometric zero-points (which are accurate to better than 4 per cent) for each of the seven UVOT broad-band filters. The calibration was performed with observations of standard stars

T. S. Poole; A. A. Breeveld; M. J. Page; W. Landsman; S. T. Holland; P. Roming; N. P. M. Kuin; P. J. Brown; C. Gronwall; S. Hunsberger; S. Koch; K. O. Mason; P. Schady; D. vanden Berk; A. J. Blustin; P. Boyd; P. Broos; M. Carter; M. M. Chester; A. Cucchiara; B. Hancock; H. Huckle; S. Immler; M. Ivanushkina; T. Kennedy; F. Marshall; A. Morgan; S. B. Pandey; M. de Pasquale; P. J. Smith; M. Still

2008-01-01

186

Galaxy Properties at the North Galactic Pole. I. Photometric Properties on Large Spatial Scales  

NASA Astrophysics Data System (ADS)

A two-color study of the galaxies detected on POSS-I in a 289 square degree region centered on the North Galactic Pole is presented. We use a variety of mapping techniques to characterize the large-scale spatial distribution of galaxies. The depth and sample size of this new survey allows, for the first time, the isolation of large photometric subsamples of galaxies in high- and low-density environments on the scale of superclusters. Our principal finding is a statistically significant difference between the mean photometric properties of these subsamples in the sense that galaxies in the high-density Coma and filament environments have redder colors and larger concentration indices than galaxies drawn from low-density interfilament regions. These results are in accord with the known morphology-density relation. Thus, appropriately chosen photometric and morphological parameters, in concert with a galaxy surface density map, can be used to select structures from the projected galaxy distribution which correspond to regions of high density. An illustration of this point is our discovery of a concentration of blue galaxies identified in our maps near the core of the Coma cluster. This feature is comprised of early-type galaxies which exhibit signs of current or recent star formation. These results are predicated on relations between morphological type and photometric parameters derived from APS scans of POSS-I. We therefore discuss the image calibration procedures used to compile our catalog of physically significant photometric parameters. We demonstrate the morphological type dependence among quantities such as mean color and image concentration index, and the lack of such a dependence for mean surface brightness.

Odewahn, S. C.; Aldering, G.

1995-11-01

187

Asteroid taxonomic signatures from photometric phase curves  

NASA Astrophysics Data System (ADS)

We explore the correlation between an asteroid's taxonomy and photometric phase curve using the H, G12 photometric phase function, with the shape of the phase function described by the single parameter G12. We explore the usability of G12 in taxonomic classification for individual objects, asteroid families, and dynamical groups. We conclude that the mean values of G12 for the considered taxonomic complexes are statistically different, and also discuss the overall shape of the G12 distribution for each taxonomic complex. Based on the values of G12 for about half a million asteroids, we compute the probabilities of C, S, and X complex membership for each asteroid. For an individual asteroid, these probabilities are rather evenly distributed over all of the complexes, thus preventing meaningful classification. We then present and discuss the G12 distributions for asteroid families, and predict the taxonomic complex preponderance for asteroid families given the distribution of G12 in each family. For certain asteroid families, the probabilistic prediction of taxonomic complex preponderance can clearly be made. In particular, the C complex preponderant families are the easiest to detect, the Dora and Themis families being prime examples of such families. We continue by presenting the G12-based distribution of taxonomic complexes throughout the main asteroid belt in the proper element phase space. The Nysa-Polana family shows two distinct regions in the proper element space with different G12 values dominating in each region. We conclude that the G12-based probabilistic distribution of taxonomic complexes through the main belt agrees with the general view of C complex asteroid proportion increasing towards the outer belt. We conclude that the G12 photometric parameter cannot be used in determining taxonomic complex for individual asteroids, but it can be utilized in the statistical treatment of asteroid families and different regions of the main asteroid belt.

Oszkiewicz, Dagmara Anna; Bowell, Edward; Wasserman, L. H.; Muinonen, Karri; Penttilä, Antti; Pieniluoma, Tuomo; Trilling, David E.; Thomas, Cristina A.

2012-05-01

188

Photometric redshift estimation using spectral connectivity analysis  

NASA Astrophysics Data System (ADS)

The development of fast and accurate methods of photometric redshift estimation is a vital step towards being able to fully utilize the data of next-generation surveys within precision cosmology. In this paper, we apply a specific approach to spectral connectivity analysis (SCA) called diffusion map. SCA is a class of non-linear techniques for transforming observed data (e.g. photometric colours for each galaxy, where the data lie on a complex subset of p-dimensional space) to a simpler, more natural coordinate system wherein we apply regression to make redshift predictions. In previous applications of SCA to other astronomical problems, we demonstrate its superiority vis-a-vis the principal components analysis, a standard linear technique for transforming data. As SCA relies upon eigen-decomposition, our training set size is limited to <~104 galaxies; we use the Nyström extension to quickly estimate diffusion coordinates for objects not in the training set. We apply our method to 350738 Sloan Digital Sky Survey (SDSS) main sample galaxies, 29816 SDSS luminous red galaxies and 5223 galaxies from DEEP2 with Canada-France-Hawaii Telescope Legacy Survey ugriz photometry. For all three data sets, we achieve prediction accuracies at par with previous analyses, and find that the use of the Nyström extension leads to a negligible loss of prediction accuracy relative to that achieved with the training sets. As in some previous analyses, we observe that our predictions are generally too high (low) in the low (high) redshift regimes. We demonstrate that this is a manifestation of attenuation bias, wherein measurement error (i.e. uncertainty in diffusion coordinates due to uncertainty in the measured fluxes/magnitudes) reduces the slope of the best-fitting regression line. Mitigation of this bias is necessary if we are to use photometric redshift estimates produced by computationally efficient empirical methods in precision cosmology.

Freeman, P. E.; Newman, J. A.; Lee, A. B.; Richards, J. W.; Schafer, C. M.

2009-10-01

189

Photometric variability of three brown dwarfs  

NASA Astrophysics Data System (ADS)

We report a study of the photometric variability of 3 low-mass, sub-stellar objects. Two of them, 2MASS 1207334-393254 and 2MASS 1139511-315921, are young (10 Myr) brown dwarfs of M8 spectral class. 2MASS 1207334-393254 was observed in the I, R, J and Y bands, through April--May 2004, and in B and I bands through March--April 2005. 2MASS 1139511-315921 was observed in the I band, from October to December, 2004. The third object, 2MASS 04234858-0414035, a field T dwarf, was observed in the I band.

Samaddar, Debasmita

190

Photometric surveys of suspected small-amplitude red variables. III: An AAVSO photometric photometry survey  

NASA Astrophysics Data System (ADS)

We have carried out a survey of the photometric (V) variability of 61 'known' or suspected small-amplitude red variables, mostly M giants. Approximately two-thirds appear to be variable; several suspected variable comparison stars have also been identified. The incidence and average amplitude of variability increase rapidly from spectral type M0 III to M6 III.

Percy, John R.; Wong, Nancy; Bohme, Dietmar; Curott, David R.; Dempsey, Frank; Fortier, George L.; Ganis, Matt; Parello, Stephanie; Landis, Howard J.; Luedeke, Kenneth D.; Pray, Donald; Smith, Michael S.; Snyder, Leroy F.; Thompson, Raymond R.; Wasson, Rick; Williams, Harold O.; Walker, William S. G.; Wood, James E.

1994-06-01

191

Titrated oxygen requirement and prognostication in idiopathic pulmonary fibrosis  

PubMed Central

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

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

2011-01-01

192

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

193

The Optical Gravitational Lensing Experiment. OGLE-III Photometric Maps of the Galactic Bulge Fields  

NASA Astrophysics Data System (ADS)

We present OGLE-III Photometric Maps of the Galactic bulge fields observed during the third phase of the OGLE project. This paper describes the last, concluding set of maps based on OGLE-III data. The maps contain precise, calibrated VI photometry of about 340 million stars from 267 fields in the Galactic bulge observed during entire OGLE-III phase (2002-2009), covering about 92 square degrees in the sky. Precise astrometry of these objects is also provided. We briefly discuss the photometry procedures and the quality of the data. We also present sample data and color-magnitude diagrams of the observed fields. All photometric data are available to the astronomical community from the OGLE Internet archive.

Szyma?ski, M. K.; Udalski, A.; Soszy?ski, I.; Kubiak, M.; Pietrzy?ski, G.; Poleski, R.; Wyrzykowski, ?.; Ulaczyk, K.

2011-06-01

194

A simple method to estimate surface reflectance parameters for three light photometric stereo  

NASA Astrophysics Data System (ADS)

A complete procedure to reconstruct part shape using a 3-light photometric stereo technique is investigated and experimentally verified. The part reflectance parameters are initially estimated and then the photometric stereo technique is applied at selected illumination directions. Finally, the recovered surface normals are integrated to reconstruct the part shape. The light sources are placed at 120° azimuth angle spacing while the slant angle is optimized according to the range of slopes found in the part surface. For a free form surface with small radii of curvature, a 45° light source slant angle is found to give better results on the global scale, with relatively lower accuracy. For a near-flat surface, a light source slant angle of 25° may be used to attain more accurate results. For surfaces having slopes less than 40° the mean surface normal recovery error is experimentally found to be less than 5°.

Younes, Mohammad A.; Al-Nady, M. A.

2008-10-01

195

A full geometric and photometric calibration method for oblique-viewing endoscopes.  

PubMed

Oblique-viewing endoscopes (oblique scopes) are widely used in computer assisted surgeries. The viewing direction of an oblique scope can be changed by rotating the scope cylinder; this extends the field of view, but also makes the geometric calibration process more difficult. Although few calibration methods have yet been developed, calibration is critical for the application of augmented-reality technologies such as stereo vision to procedures involving oblique scopes. Moreover, to our knowledge, no photometric calibration method has yet been introduced for endoscopes, even though such calibration is important for illumination-based visualization techniques such as shape-from-shading. In this paper, we present a complete calibration process for oblique-viewing endoscopes, estimating both geometric and photometric properties. Experimental results demonstrate that our methods are practical and accurate. PMID:20433318

Wu, C; Jaramaz, B; Narasimhan, S G

2010-01-01

196

40 CFR 60.648 - Optional procedure for measuring hydrogen sulfide in acid  

Code of Federal Regulations, 2010 CFR

...Optional procedure for measuring hydrogen sulfide in acid] 40 PROTECTION...Optional procedure for measuring hydrogen sulfide in acid gas--Tutwiler...method consists of titrating hydrogen sulfide in a gas sample...

2009-07-01

197

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

198

Two-phase titration of cerium(III) by permanganate  

SciTech Connect

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

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

1987-02-01

199

Photometric determination of trace quantities of phenol in hydrophilic extracts  

SciTech Connect

An extraction-photometric method has been developed for determination of trace quantities of phenol in aqueous solutions. Phenol is extracted with hydrophilic solvents (aliphatic alcohols C{sub 2}-C{sub 4}, acetone, methyl ethyl ketone) followed by photometric analysis of the extract.

Korenman, Ya.I.; Ermolaeva, T.N.; Kuchmenko, T.A.; Mishina, A.V.

1994-03-10

200

3D Reconstruction Using Shape from Photometric Stereo and Contours  

Microsoft Academic Search

In this work, we further discuss an approach to 3D shape recovery by combining photometric stereo and shape from contours methods. Surfaces recovered by photometric stereo are aligned, adjusted and merged according to a preliminary 3D model obtained by shape from contours. Comparisons are conducted to evaluate the performances of different methods. It has been found that the proposed combination

Chia-Yen Chen; Reinhard Klette; Chi-Fa Chen

201

Dense Photometric Stereo: A Markov Random Field Approach  

Microsoft Academic Search

We address the problem of robust normal reconstruction by dense photometric stereo, in the presence of com- plex geometry, shadows, highlight, transparencies, varia ble attenuation in light intensities, and inaccurate estim ation in light directions. The input is a dense set of noisy photometric images, conveniently captured by using a very sim- ple set-up consisting of a digital video camera,

Tai-pang Wu; Kam-lun Tang; Chi-keung Tang; Tien-tsin Wong

2006-01-01

202

Reactivity between carbon fibres and anhydride. A study by radiochemical titration and ToF-SIMS analysis  

Microsoft Academic Search

This paper deals with the radiochemical titration of carbon fibres (ex-PAN AS4 from Hercules) with 14C labelled succinic anhydride in view of quantifying the reactivity between anhydride groups and the functionalities (amine, hydroxyl, etc.) of C fibres. A transesterification reaction due to the chemical labelling procedure is observed and is confirmed by time-of-flight secondary ion mass spectrometry (ToF-SIMS) analyses. It

V. Carlier; P. Franquinet; M. Sclavons; R. Legras; C. Poleunis; L. T. Weng; P. Bertrand; P. Dréze

1998-01-01

203

mCP stars with photometrically simple behaviour  

NASA Astrophysics Data System (ADS)

We analyzed uvby and Hp light curves of 19 well-observed magnetic CP stars selected from the On-line Database of Photometric Observations of mCP Stars, of which light curves in all the five colours were similar. We assumed that among these stars with photometrically simple behaviour (PSB) could be found ones with a single photometric spot. The knowledge gained by analysing those simple situations would help us comprehend more complicated cases. Light curves of the 19 PSB mCP stars proved generally to be nearly symmetrical, but surprisingly diverse. The analysis shows that only in the case of HD110956B, HD188041, and perhaps HD193722 are we able to explain their photometric behaviour by a simple one-spot model. Occurrence of more than one photometric spot on an mCP star is therefore more typical.

Mikulášek, Z.; Gráf, T.; Krti?ka, J.; Zverko, J.; Žiž?ovský, J.

2008-04-01

204

Ha Emission extraction using Narrowband Photometric Filters  

NASA Astrophysics Data System (ADS)

Maria Mitchell Observatory has explored using Narrowband Photometric (<100A) filters to substitute for spectroscopic observations. The method is thought to have significant signal to noise advantages over spectroscopic observations for small telescopes. These small telescopes offer advantages for projects requiring intensive monitoring where telescope time is limited on larger telescopes. RR Tau, a suspected UXOR, was intensively observed by the MMO 0.6 M RC in Nantucket, Mass and the .29M W28 AAVSOnet telescope from Cloudcroft, New Mexico during the 2010 Winter & Spring season. Observations were made in Ha with 45A and 100A narrowband filters as well as the continuum at 6450 A with 50A and 100A filters. Ha emission was extracted with an error of 8% and compared to the change in the continuum. RR Tau exhibited a 30% change in emission while the continuum change by over a factor of 5.

Walker, Gary E.

2011-05-01

205

Photometric Variability of Magnetic White Dwarfs  

NASA Astrophysics Data System (ADS)

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

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

2013-01-01

206

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

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

207

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

208

Multiband photometric decomposition of nuclear stellar disks  

NASA Astrophysics Data System (ADS)

Context. Small, bright stellar disks with scale lengths of a few tens of parsec are known to reside in the center of galaxies. They are believed to have formed in a dissipational process as the end result of star formation in gas either accreted during a merging (or acquisition) event or piled up by the secular evolution of a nuclear bar. Only a few of them have been studied in detail to date. Aims: Using archival Hubble Space Telescope (HST) imaging, we investigate the photometric parameters of the nuclear stellar disks hosted by three early-type galaxies in the Virgo cluster, NGC 4458, NGC 4478, and NGC 4570, to constrain the process that forms their stars. Methods: The central surface brightness, scale length, inclination, and position angle of the nuclear disks were derived by adopting the photometric decomposition method introduced by Scorza & Bender and assuming the disks to be infinitesimally thin and exponential. Results: The location, orientation, and size of the nuclear disks is the same in all the images obtained with the Wide Field Planetary Camera 2 and Advanced Camera for Surveys and available in the HST Science Archive. The scale length, inclination, and position angle of each disk are constant within the errors in the observed U, B, V, and I passbands, independently of their values and the properties of the host spheroid. Conclusions: We interpret the absence of color gradients in the stellar population of the nuclear disks as the signature that star formation homogeneously occurred along their length. An inside-out formation scenario is, instead, expected to produce color gradients and is therefore ruled out.

Morelli, L.; Cesetti, M.; Corsini, E. M.; Pizzella, A.; Dalla Bontà, E.; Sarzi, M.; Bertola, F.

2010-07-01

209

Standard Stars for the BYU ? Photometric System  

NASA Astrophysics Data System (ADS)

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

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

2013-01-01

210

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

211

Treatment of breakthrough cancer pain: to titrate or to proportionate?  

PubMed

Abstract Breakthrough cancer pain can be treated effectively by rapid-onset opioids, such as sublingual fentanyl. However, it remained unclear how the optimal dose of sublingual fentanyl should be determined. Dosing proportional to basic opioid regimen is now proposed as an alternative to dose titration. PMID:23971682

Hans, Guy H

2013-09-05

212

Macromolecular Effects on the Titration Curves of Parotid Gland Fluid.  

National Technical Information Service (NTIS)

Macromolecules were found to act as additives to the total buffering action in parotid saliva. This additive effect was related to the proteins in the gland fluid, and could be demonstrated by analyzing changes in the end-point segments of titration curve...

K. C. Hoerman G. E. Clark A. Y. Balekjian

1968-01-01

213

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

SciTech Connect

Gold, platinum, and several other platinum metals can be determined by titration with cetylpyridinium chloride (CPC). CPC forms a precipitate with AuCl{sub 4}{sup {minus}} and PtCl{sub 6}{sup 2{minus}}. Differentiation of AuCl{sub 4{minus}} and PtCl{sub 6}{sup 2{minus}} with this titrant is not possible; however, their sum can be determined. Titration with tetraphenylarsonium chloride at pH 1 is selective for tetrachloroaurate, which thus can be determined in the presence of hexachloroplatinate. Hexachloroosmate(IV), tetrachloroplatinite(II), tetrachloropalladate(II), hexachloropalladate(IV), and hexachloroiridate(IV) can also be determined potentiometrically vs. CPC. The indicating electrode is prepared by coating a spectroscopic graphite rod with a solution of poly(vinyl chloride) (PVC) and dioctylphthalate (DOP) in tetrahydrofuran (THF). Gold in gold cyanide plating baths and in potassium aurocyanide can be determined by potentiometric titration vs standard silver nitrate, using a silver ion-selective indicating electrode. The monovalent gold need not be converted to the trivalent state with aqua regia, resulting in a considerable saving of time and effort. Free cyanide and aurocyanide can be titrated sequentially by this method. Chloride does not interfere and can, in fact, also be sequentially determined. 17 refs., 2 figs., 3 tabs.

Selig, W.S.

1991-02-04

214

Charge determination of synthetic cationic polyelectrolytes by colloid titration  

Microsoft Academic Search

The stoichiometric interaction between oppositely charged polyelectrolytes forms the basis of the technique of colloid titration. This can be used, for instance, to determine the charge density of a cationic polyelectrolyte, using an anionic polyelectrolyte of known charge density, such as potassium polyvinyl sulphate (PPVS). The technique requires a suitable method of end-point detection and there are several possibilities. In

Sang-kyu Kam; John Gregory

1999-01-01

215

Mapping glycoside hydrolase substrate subsites by isothermal titration calorimetry  

Microsoft Academic Search

Relating thermodynamic parameters to structural and biochemical data allows a better understanding of substrate binding and its contribution to catalysis. The analysis of the binding of carbohydrates to proteins or enzymes is a special challenge because of the multiple interactions and forces involved. Isothermal titration calorimetry (ITC) provides a direct measure of binding enthalpy (Ha) and allows the determination of

Gennady Zolotnitsky; Uri Cogan; Noam Adir; Vered Solomon; Gil Shoham; Yuval Shoham

2004-01-01

216

Isothermal Titration Calorimeter For Research And Education (DURIP-10).  

National Technical Information Service (NTIS)

We have purchased a state-of-the-art MicroCal Auto-iTC200 Isothermal Titration Calorimetry (ITC) System. ITC is the gold standard for measuring biomolecular interactions. ITC simultaneously determines all binding parameters in a single experiment which is...

2011-01-01

217

QUANTIFYING PHOTOMETRIC REDSHIFT ERRORS IN THE ABSENCE OF SPECTROSCOPIC REDSHIFTS  

SciTech Connect

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

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

2010-12-10

218

Optimal reconstruction of approximate planar surfaces using photometric stereo.  

PubMed

Photometric stereo can be used to obtain a fast and noncontact surface reconstruction of Lambertian surfaces. Despite several published works concerning the uncertainties and optimal light configurations of photometric stereo, no solutions for optimal surface reconstruction from noisy real images have been proposed. In this paper, optimal surface reconstruction methods for approximate planar textured surfaces using photometric stereo are derived, given that the statistics of imaging errors are measurable. Simulated and real surfaces are experimentally studied, and the results validate that the proposed approaches improve the surface reconstruction especially for the high-frequency height variations. PMID:19834147

Kuparinen, Toni; Kyrki, Ville

2009-12-01

219

Photometric normalization of LROC WAC images  

NASA Astrophysics Data System (ADS)

The Lunar Reconnaissance Orbiter Camera (LROC) Wide Angle Camera (WAC) acquires near global coverage on a monthly basis. The WAC is a push frame sensor with a 90° field of view (FOV) in BW mode and 60° FOV in 7-color mode (320 nm to 689 nm). WAC images are acquired during each orbit in 10° latitude segments with cross track coverage of ~50 km. Before mosaicking, WAC images are radiometrically calibrated to remove instrumental artifacts and to convert at sensor radiance to I/F. Images are also photometrically normalized to common viewing and illumination angles (30° phase), a challenge due to the wide angle nature of the WAC where large differences in phase angle are observed in a single image line (±30°). During a single month the equatorial incidence angle drifts about 28° and over the course of ~1 year the lighting completes a 360° cycle. The light scattering properties of the lunar surface depend on incidence(i), emission(e), and phase(p) angles as well as soil properties such as single-scattering albedo and roughness that vary with terrain type and state of maturity [1]. We first tested a Lommel-Seeliger Correction (LSC) [cos(i)/(cos(i) + cos(e))] [2] with a phase function defined by an exponential decay plus 4th order polynomial term [3] which did not provide an adequate solution. Next we employed a LSC with an exponential 2nd order decay phase correction that was an improvement, but still exhibited unacceptable frame-to-frame residuals. In both cases we fitted the LSC I/F vs. phase angle to derive the phase corrections. To date, the best results are with a lunar-lambert function [4] with exponential 2nd order decay phase correction (LLEXP2) [(A1exp(B1p)+A2exp(B2p)+A3) * cos(i)/(cos(e) + cos(i)) + B3cos(i)]. We derived the parameters for the LLEXP2 from repeat imaging of a small region and then corrected that region with excellent results. When this correction was applied to the whole Moon the results were less than optimal - no surprise given the variability of the regolith from region to region. As the fitting area increases, the accuracy of curve fitting decreases due to the larger variety of albedo, topography, and composition. Thus we have adopted an albedo-dependent photometric normalization routine. Phase curves are derived for discreet bins of preliminary normalized reflectance calculated from Clementine global mosaic in a fitting area that is composed of predominantly mare in Oceanus Procellarum. The global WAC mosaic was then corrected pixel-by-pixel according to its preliminary reflectance map with satisfactory results. We observed that the phase curves per normalized-reflectance bins become steeper as the reflectance value increases. Further filtering by using FeO, TiO2, or optical maturity [5] for parameter calculations may help elucidate the effects of surface composition and maturity on photometric properties of the surface. [1] Hapke, B.W. (1993) Theory of Reflectance and Emittance Spectroscopy, Cambridge Univ. Press. [2] Schoenberg (1925) Ada. Soc. Febb., vol. 50. [3] Hillier et al. (1999) Icarus 141, 205-225. [4] McEwen (1991) Icarus 92, 298-311. [5] Lucey et al. (2000) JGR, v105, no E8, p20377-20386.

Sato, H.; Denevi, B.; Robinson, M. S.; Hapke, B. W.; McEwen, A. S.; LROC Science Team

2010-12-01

220

Development of an isothermal titration microcalorimetric system with digital control and dynamic power peltier compensation. II. Characterization and operation mode. Myoglobin adsorption onto polymeric latex particles  

NASA Astrophysics Data System (ADS)

In a previous article a comprehensive description of an isothermal titration microcalorimeter with Peltier compensation was reported. This work deals with the characterization procedure and the operation mode. The transfer function parameters (time constants, calibration constants, and thermal properties of the system components) have been determined using a rigorous physical model for the microcalorimeter. To check the good performance of the instrument, titration experiments of cytidine and adenosine protonation have been carried out. Finally, as an example of the instrument applicability, differential heat measurements of myoglobin adsorption onto polymeric (polystyrene) latex particles are presented.

Velázquez-Campoy, A.; López-Mayorga, O.; Cabrerizo-Vílchez, M. A.

2000-04-01

221

Application of the finite element simulation method to the adiabatic and potentiometric corrections of calorimetric titration data.  

PubMed

A general numerical analysis procedure is described which has been applied to an automated differential pH-thermal titration apparatus operated isoperibolically to obtain thermal corrections for heat loss. It is based on the Direct Byte (D-B) finite element computer simulation technique (FEST) applied to the heat conduction behavior of the instrument with time. Thermal constants of the numerical model are determined, and the results of the correction for titration data obtained from acid-base runs show that a constant upper baseline is achieved using this technique for both fast and slow reactions to an accuracy of 2%. The method is equally valid for endothermic and exothermic reactions. PMID:3998381

Davids, N; Berger, R L; Marini, M A

1985-03-01

222

Sulfur Chemiluminescence Detection Compared to Sulfur Flame Photometric Detection.  

National Technical Information Service (NTIS)

Detection of compounds containing sulfur heteratom is traditionally accomplished using flame photometric detection (FPD). Sulfur chemiluminescence detection (SCD) is an alternative to FPD. This report compares the FPD with two SCD configurations using var...

M. W. Elizy L. G. Janes

1998-01-01

223

IMPROVED PHOTOMETRIC REDSHIFTS WITH SURFACE LUMINOSITY PRIORS  

SciTech Connect

We apply Bayesian statistics with prior probabilities of galaxy surface luminosity (SL) to improve photometric redshifts. We apply the method to a sample of 1266 galaxies with spectroscopic redshifts in the GOODS North and South fields at 0.1 {approx}< z {approx}< 2.0. We start with spectrophotometric redshifts (SPZs) based on Probing Evolution and Reionization Spectroscopically grism spectra, which cover a wavelength range of 6000-9000 A, combined with (U)BViz(JHK) broadband photometry in the GOODS fields. The accuracy of SPZ redshifts is estimated to be {sigma}({delta}(z)) = 0.035 with an systematic offset of -0.026, where {delta}(z) = {delta}z/(1 + z), for galaxies in redshift range of 0.5 {approx}< z {approx}< 1.25. The addition of the SL prior probability helps break the degeneracy of SPZ redshifts between low redshift 4000 A break galaxies and high-redshift Lyman break galaxies which are mostly catastrophic outliers. For the 1138 galaxies at z {approx}< 1.6, the fraction of galaxies with redshift deviation {delta}(z)>0.2 is reduced from 15.0% to 10.4%, while the rms scatter of the fractional redshift error does not change much.

Xia Lifang; Cohen, Seth; Malhotra, Sangeeta; Rhoads, James; Grogin, Norman; Windhorst, Rogier A. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287-1404 (United States); Hathi, Nimish P. [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Pirzkal, Nor; Xu Chun [Space Telescope Science Institute, Baltimore, MD 21218 (United States)], E-mail: lifang.xia@asu.edu

2009-07-15

224

Photometric Calibration of SNLS (Regnault+, 2009)  

NASA Astrophysics Data System (ADS)

This is the photometric calibration of the SuperNova Legacy Survey (SNLS) three year dataset. The SNLS corresponds to the DEEP component of the larger Canada-France-Hawaii Telescope Legacy Survey (CFHTLS). The SNLS repeatedly monitors four one square degree fields (labeled D[1-4]) with the MegaCam wide-field imager, in the g, r, i and z bands. u-band observations of the same fields are also available, although not formally part of the SNLS dataset. The non-uniformities of the MegaCam imager photometric response have been mapped as a function of the position on the focal plane. The fluxes, measured on the survey images processed with the CFHT Elixir pipeline, have been corrected for these non-uniformities in order to obtain measurements that are uniform at the ~1% level. The MegaCam passband transmissions were found to be non-uniform, the filters being 3 to 6 nanometers bluer on the edges of the camera than on the center. This result agrees with the filter scans provided by the filter manufacturer (Sagem/REOSC). This has important consequences on the definition of the MegaCam magnitudes: the natural magnitude system depends on the focal plane location where the observations were made. In order not to break the connection between calibrated magnitudes and their physical flux counterparts, we chose to report the *natural magnitudes* of each object, measured in the MegaCam passbands, at the focal plane location where the object was observed. We call this system, "Local Natural Magnitudes". The non-uniformities of the MegaCam effective passbands are small and, for main sequence stellar objects, they may be accounted for using linear color corrections. The relation between the Local Natural Magnitudes of a given star, observed at two locations x_0 and x of the focal plane are: g|x = g|x0 + dkggr(x) * ( (g-r)|x0 - (g-r)BD+17|x_0 ) ... z|x = z|x0 + dkziz(x) * ( (i-z)|x0 - (i-z)BD+17|x_0 ) where the dk(x) are (position dependant) color terms. We provide dk(x) maps for each MegaCam band (see below). The SNLS 3 year calibration relies on the (Landolt, 1992AJ....104..340) standard star catalog. Landolt fields are observed during each photometric night along with the SNLS fields. Zero-points are derived from these observations. Stable and isolated stars are detected on the SNLS fields and selected as "tertiary standards". The calibrated magnitudes of each tertiary standard obtained under photometric conditions are combined to produce a calibration catalog for each SNLS field. To interpret the tertiary standard magnitudes as physical fluxes, we need a primary standard, i.e. a star with known MegaCam magnitudes and whose spectral energy distribution has been measured absolutely. The SNLS uses BD+17 4708 whose SED has been measured in Bohlin & Gilliland, 2004, Cat. using the HST STIS and NICMOS spectrographs. BD+17 4708 has not been directly observed by SNLS, however, its MegaCam magnitudes were inferred from its known Landolt magnitudes (this paper, table 7). The tertiary star Local Natural Magnitudes are defined so that the associated physical broadband flux f|x is given by: f|x = 10{-0.4*(m|x-mref)}*{int}[Sref(l)*T(l;x)]dl where m|x is the tertiary star magnitudes at location x on the focal plane, mref is the MegaCam magnitude of BD+17 4708 (at the center of the focal plane, see table 7 of this paper), Sref(l) is the SED of BD+17 4708 measured in 2004AJ....128.3053B, and T(l;x) is the effective passband of MegaCam at location x. Attached is all the necessary information to tie MegaCam observations to this system. We provide (a) the griz magnitudes of the SNLS tertiary standards for all four SNLS fields (b) the MegaCam open transmission and the ugriz MegaCam filter scans at various position along a diagonal (c) the final uncertainty budget in the form of 3 covariance matrices. The u-band observations of the SNLS DEEP fields are not formally part of the SNLS. Nevetheless we give u-band magnitudes for a subset of the SNLS tertiary stars. (22 data files).

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.

2009-08-01

225

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

226

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

227

A photometric method to analyze induced erythrocyte shape changes  

Microsoft Academic Search

In this paper, a photometric method was introduced to quantify biochemically-induced red blood cell (RBC) shape changes when no shear force was acting on the cells. To obtain the photometric RBC shape parameter (RF1), a monolayer of point-attached RBCs was prepared on the floor of a flat flow chamber and the transmission of light perpendicular to the monolayer plane was

G. M. Artmann; A. Li; J. Ziemer; G. Schneider; U. Sahm

1996-01-01

228

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

229

APPLICATION OF CHEMICAL MODIFIED ELECTRODE IN COULOMETRIC TITRATION FOR DETERMINATION OF SOLANESOL  

Microsoft Academic Search

The problem of large deviation of determination of solanesol by coulometric titration when using direct titration technique and double Pt electrodes amperometric method indicating the end-point has been resolved. In titration process, solanesol, an electroinactive species, can be adsorbed on the surfaces of Pt electrodes and inhibit electrode reactions of Br and Br2. Therefore, when titration reaches the end-point, the

Ge Zhao; Jianying Qu; Meng Liu; Kuaizhi Liu; Zuliang Du

2002-01-01

230

Solubility of TTCP and ?-TCP by solid titration  

Microsoft Academic Search

ObjectiveUsing solid titration with hydroxyapatite (HAp) and octacalcium phosphate, HAp has been found to be more stable than dicalcium phosphate dihydrate (DCPD) even at lower pH, inconsistent with the widely reported view that DCPD is less soluble than other calcium phosphates below pH 4.2. A check of the behaviour of other calcium phosphates (TTCP; Ca\\/P: 2.00 and ?-TCP; Ca\\/P: 1.33)

H.-B. Pan; B. W. Darvell

2009-01-01

231

Automatic karl fischer titration of moisture in sunflower seed  

Microsoft Academic Search

An automatic Karl Fischer (KF) titrator of the motor-driven buret type was applied to the determination of moisture in sunflower\\u000a seed. A study of the effect of sample size on KF moisture analysis showed a significant decrease in moisture content with\\u000a increase in sample size from 1 to 5 g. In the moisture range of 5.5–10.5%, a sample size of

James A. Robertson; W. R. Windham

1983-01-01

232

Solubility of dicalcium phosphate dihydrate by solid titration.  

PubMed

Solid-titration results for hydroxyapatite (HAp), octacalcium phosphate, beta-tricalcium phosphate and tetracalcium phosphate have shown that the only stable phase in 100 mmol x l(-1) KCl at 37 degrees C is HAp. In particular, dicalcium phosphate dihydrate (DCPD) did not form at pH <4.2 (where it is otherwise believed to be stable) except as a metastable phase under conditions of slight supersaturation. The behaviour of DCPD itself under the same conditions requires checking. Solid titration was used to determine the apparent solubility of DCPD in a 100-mmol x l(-1) KCl solution at 37.0 +/- 0.1 degrees C over the pH range 3.2-11.6. The constitution of the precipitate was determined by X-ray diffraction, particle morphology was observed by scanning and transmission electron microscopy, and the precipitate Ca/P ratio was calculated by energy-dispersive X-ray analysis. The titration curve for DCPD was substantially lower than the position reported elsewhere. DCPD was the only identified phase at equilibrium at pH 3.60 and 4.50, but HAp was formed after seeding with 1 mg HAp at DCPD equilibrium at pH 4.47, 3.60 and 3.30. It is concluded that the titration curve observed for DCPD corresponds to the solubility isotherm for the phase, but that this represents a metastable equilibrium. HAp is more stable than DCPD, particularly below pH 4.2. The implications for calcium phosphate studies are profound as the reverse is generally believed to be true. Thus, solubility results and the nature of the carious lesion need reconsideration. PMID:19439946

Pan, H-B; Darvell, B W

2009-05-08

233

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

234

Phosphorus-doped and undoped glassy carbon indicator electrodes in controlled-current potentiometric titrations of bromide- or chloride-containing active ingredients in some pharmaceutical preparations.  

PubMed

Phosphorus-doped glassy carbon (as a novel material) and glassy carbon (Sigri commercial sample) were applied as potentiometric indicator electrodes in the titrimetric determination of active components with bromide or chloride in their molecules in different pharmaceutical preparations (Buscopan, Prostigmine, Isoptin, Bedoxin, Akineton and Trodon). After the necessary pre-treatment of the electrode surfaces and sample dissolution, the halide was titrated with a standard solution of silver nitrate (indirect determination). Amounts of 10-20 micromol of the investigated active ingredients per titration were determined with a relative standard deviation that, depending on the nature of indicator electrode, determined molecules and filler components, was in the range of 0.3-2.7%. The results obtained were compared with those of the official methods and with those obtained by potentiometric titrations using silver electrode. The titrimetric procedures developed are relatively fast, easy, economical and can be used to analyse of a large number of pharmaceutical products. PMID:15708666

Abramovi?, Biljana F; Guzsvány, Valéria J; Gaál, Ferenc F

2005-02-23

235

Fentanyl buccal tablet for breakthrough cancer pain: why titrate?  

PubMed

Breakthrough cancer pain is a significant problem for many patients with cancer because of the fast onset and often unpredictable nature of the pain episodes. The rapid onset opioids therefore have a central role to play in the management of breakthrough cancer pain. The rapid onset opioid fentanyl buccal tablet provides a fast analgesic effect and is easy to administer. However, titration of the medication is essential in order to optimize the management of pain. This is because individual patient characteristics, comorbidities, and other treatments may influence the absorption, pharmacokinetics, and pharmacodynamics of drugs. It is therefore important to individualize treatment by determining the effective dose for each patient, which is the dose that provides adequate analgesia and minimizes undesirable adverse effects. Data from clinical studies of fentanyl buccal tablet show that patients' effective doses ranged from 100 to 800 µg per episode, highlighting the need for the titration process. Following successful dose titration, treatment with fentanyl buccal tablet can achieve significant pain relief as early as 10 minutes after administration, resulting in a high level of patient satisfaction. PMID:20807349

Kleeberg, Ulrich R; Filbet, Marilène; Zeppetella, Giovambattista

2010-08-27

236

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

ERIC Educational Resources Information Center

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

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

2012-01-01

237

Titration of strong and weak acids by sequential injection analysis technique  

Microsoft Academic Search

A sequential injection analysis (SIA) titration method has been developed for acid-base titrations. Strong and weak acids in different concentration ranges have been titrated with a strong base. The method is based on sequential aspiration of an acidic sample zone and only one zone of the base into a carrier stream of distilled water. On their way to the detector,

Silla Maskula; Johan Nyman; Ari Ivaska

2000-01-01

238

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

Microsoft Academic Search

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

Lawrence V. Hankes; Janis John Vitols

239

Correction for Hemolysis in a Photometric Method for Assaying Sulfobromophthalein in the Blood of Cattle in Tests for Hepatic Function1  

Microsoft Academic Search

SUMMARY Varying degrees of hemolysis of blood have interfered with photometric measurements of the dye sulfobromophthalein (Bromsulphalein or BSP) in studies of hepatic function. In the usual procedures plasma blanks are measured in acidic media, since dye colors are developed in basic media. However, the optical density (O.D.) of hemoglobin (as hema- tin), when measured in an acidic medium, differs

R. R. Anderson; J. P. Mixner

1960-01-01

240

Photometric reverberation mapping of 3C 120  

NASA Astrophysics Data System (ADS)

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

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

2012-09-01

241

Photometric Survey for Asynchronous Binary Asteroids  

NASA Astrophysics Data System (ADS)

Asynchronous binary asteroids have been found to be abundant among fast- spinning near-Earth asteroids (NEAs) smaller than 2 km in diameter; Pravec et al. (2005, Icarus, submitted) derived that 15 +/- 4 % of NEAs in the size range 0.3 to 2 km are binary with the secondary-to-primary mean diameter ratio >=0.18. The early re-sults from the surveys of the Vesta family and the Hungaria group (Ryan et al., 2004, Planet. Space Sci. 42, 1093; 2004, Bull. Amer. Astron. Society 36, 1181; Warner et al., 2005, IAU Circ. 8511) suggest that the popula-tion extends beyond the region of terrestrial planets, but with characteristics shifted to larger sizes and longer periods; the four known binaries in the Vesta family/Hungaria group are 3 to 6 km large and they have primary rotation periods in a range of 3 to ~4 h, i.e., on the tail of the distribution of primary rotation periods of NEAs. The comparison suggests that formation and evolution mechanisms of asynchronous NEA and main-belt binaries may be similar and are related to their fast spins and rubble-pile structure. None of the current theories of their formation of evolution, however, explains the observed properties of both NEA and main- belt asynchronous bina-ries in full. We have established a collaborative observational program, called "Photometric Survey for Asynchro-nous Binary Asteroids" to discover and describe asynchronous binaries over a range of heliocentric distances from NEAs through Mars-crossers to inner main-belt asteroids. One new binary Amor asteroid, 2005 AB has been found during the first few months of the survey operation (Reddy et al., 2005, IAU Circ. 8483), and we have obtained follow-up data for two other binary systems. I outline the motivations, the technique, and the strategy of the Survey.

Pravec, P.

2005-05-01

242

LESS photometric redshift survey (Wardlow+, 2011)  

NASA Astrophysics Data System (ADS)

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

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

2012-02-01

243

Simple Modification of Karl-Fischer Titration Method for Determination of Water Content in Colored Samples  

PubMed Central

The most commonly used technique for water content determination is Karl-Fischer titration with electrometric detection, requiring specialized equipment. When appropriate equipment is not available, the method can be performed through visual detection of a titration endpoint, which does not enable an analysis of colored samples. Here, we developed a method with spectrophotometric detection of a titration endpoint, appropriate for moisture determination of colored samples. The reaction takes place in a sealed 4?ml cuvette. Detection is performed at 520?nm. Titration endpoint is determined from the graph of absorbance plotted against titration volume. The method has appropriate reproducibility (RSD = 4.3%), accuracy, and linearity (R2 = 0.997).

Tavcar, Eva; Turk, Erika; Kreft, Samo

2012-01-01

244

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

245

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

246

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

247

On Differential Photometric Reconstruction for Unknown, Isotropic BRDFs.  

PubMed

This paper presents a comprehensive theory of photometric surface reconstruction from image derivatives in the presence of a general, unknown isotropic BRDF. We derive precise topological classes up to which the surface may be determined and specify exact priors for a full geometric reconstruction. These results are the culmination of a series of fundamental observations. First, we exploit the linearity of chain rule differentiation to discover photometric invariants that relate image derivatives to the surface geometry, regardless of the form of isotropic BRDF. For the problem of shape-from-shading, we show that a reconstruction may be performed up to isocontours of constant magnitude of the gradient. For the problem of photometric stereo, we show that just two measurements of spatial and temporal image derivatives, from unknown light directions on a circle, suffice to recover surface information from the photometric invariant. Surprisingly, the form of the invariant bears a striking resemblance to optical flow; however, it does not suffer from the aperture problem. This photometric flow is shown to determine the surface up to isocontours of constant magnitude of the surface gradient, as well as isocontours of constant depth. Further, we prove that specification of the surface normal at a single point completely determines the surface depth from these isocontours. In addition, we propose practical algorithms that require additional initial or boundary information, but recover depth from lower order derivatives. Our theoretical results are illustrated with several examples on synthetic and real data. PMID:24136432

Chandraker, Manmohan; Bai, Jiamin; Ramamoorthi, Ravi

2013-12-01

248

On Differential Photometric Reconstruction for Unknown, Isotropic BRDFs.  

PubMed

We present a comprehensive theory of photometric reconstruction from image derivatives, in the presence of a general, unknown isotropic BRDF. We derive precise topological classes up to which the surface may be determined and specify exact priors for a full geometric reconstruction. These results are the culmination of a series of fundamental observations. First, we exploit the linearity of differentiation to discover BRDF-independent photometric invariants. For the problem of shape from shading, we show that isocontours of constant magnitude of the gradient may be recovered. For the problem of photometric stereo, we derive a photometric flow that relates image derivatives to surface geometry, using just two measurements of spatial and temporal image derivatives from unknown light directions on a circle. The photometric flow is shown to determine the surface up to isocontours of constant magnitude of the surface gradient, as well as isocontours of constant depth. Further, we prove that specification of the surface normal at a single point completely determines the surface depth from these isocontours. Additionally, we propose practical algorithms that require initial or boundary information, but recover depth from lower order derivatives. Our theoretical results are illustrated with several examples on synthetic and real data. PMID:23045376

Chandraker, Manmohan; Bai, Jiamin; Ramamoorthi, Ravi

2012-10-01

249

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

250

Semi-automated potentiometric titration method for uranium characterization.  

PubMed

The manual version of the potentiometric titration method has been used for certification and characterization of uranium compounds. In order to reduce the analysis time and the influence of the analyst, a semi-automatic version of the method was developed in the Brazilian Nuclear Energy Commission. The method was applied with traceability assured by using a potassium dichromate primary standard. The combined standard uncertainty in determining the total concentration of uranium was around 0.01%, which is suitable for uranium characterization. PMID:22154105

Cristiano, B F G; Delgado, J U; da Silva, J W S; de Barros, P D; de Araújo, R M S; Lopes, R T

2011-11-25

251

Photometric Study of the v2 Cepheid in M13  

NASA Astrophysics Data System (ADS)

Small amateur telescopes equipped with photometric filters and CCD cameras constitute a valuable tool for variable star research. In this regard, we have carried out a photometric campaign over last three years (May 2001-November 2003), centered on the globular cluster M13 (NGC 6205). In this work, we present the results obtained from the photometric analysis of the BL Her cepheid V2 data, that can be used to estimate the distance to M13 (8.0 kpc), as well as some physical features of the star (mean radius: about 13 solar radii, effective temperature: about 6630 K, mean absolute bolometric magnitude: -1.49, and mean luminosity of 316 times the solar luminosity).

Bordonau, Violat; F.; Bajo, Sanchez; F.; Andreu, Bennasar; T.

2005-12-01

252

Photometric analysis of V30 of open cluster NGC 7789  

NASA Astrophysics Data System (ADS)

We present the photometric solutions of the variable star V30We follow the Jahn et al. (1995) nomenclature for variable names. that is in the foreground of intermediate open cluster NGC 7789. The observations were done in the V passband using the 2 m telescope at the IUCAA-Girawali Observatory in India. The analysis is done using the Wilson-Devinney Code (2003) and the fitted light curve is presented. The photometric solutions reveal a W-subtype contact configuration. The photometric mass ratio is found to be 0.395 and the absolute masses and radii for the components are deduced as 1.25 Ms and 0.97 Rs for the primary and 0.49 Ms and 0.93 Rs for the secondary, respectively. No signature of third light is found in the system.

Kiron, Yellapragada Ravi; Sriram, Kandulapati; Vivekananda Rao, Pasagada

2011-09-01

253

Long-term photometric monitoring of WASP-3b  

NASA Astrophysics Data System (ADS)

Long-term and high-precision photometric observations of planet host stars may provide important auxiliary information for exoplanet-atmosphere research because they allow to investigate the intrinsic stellar variability, as well as to determine transit ephemeris more accurately. Here we present results fromthe photometric follow-up of known transiting close-in giant planets that has been conducted with the CAB robotic telescope over the past two years. In particular, we discuss details of the hot, gas giant exoplanet WASP- 3b. An analysis of new transit observations, together with those available in the literature, showed strong evidence of transit duration variations (TDV) in this planetary system and confirmed the presence of transit time variations (TTV). We briefly present an upto- date review with additional data from the ongoing photometric monitoring campaign and discuss possible scenarios to interpret the data.

Eibe, M.-T.; Cuesta, L.; Ullan, A.; Perez-Verde, A.; Navas, J.

2012-09-01

254

Photometric imaging in particle size measurement and surface visualization.  

PubMed

The aim of this paper is to give an insight into photometric particle sizing approaches, which differ from the typical particle size measurement of dispersed particles. These approaches can often be advantageous especially for samples that are moist or cohesive, when dispersion of particles is difficult or sometimes impossible. The main focus of this paper is in the use of photometric stereo imaging. The technique allows the reconstruction of three-dimensional images of objects using multiple light sources in illumination. The use of photometric techniques is demonstrated in at-line measurement of granules and on-line measurement during granulation and dry milling. Also, surface visualization and roughness measurements are briefly discussed. PMID:21075186

Sandler, Niklas

2010-11-12

255

CALIBRATING PHOTOMETRIC REDSHIFT DISTRIBUTIONS WITH CROSS-CORRELATIONS  

SciTech Connect

The next generation of proposed galaxy surveys will increase the number of galaxies with photometric redshift identifications by two orders of magnitude, drastically expanding both the redshift range and detection threshold from the current state of the art. Obtaining spectra for a fair subsample of these new data could be cumbersome and expensive. However, adequate calibration of the true redshift distribution of galaxies is vital to tapping the potential of these surveys to illuminate the processes of galaxy evolution and to constrain the underlying cosmology and growth of structure. We examine here an alternative to direct spectroscopic follow-up: calibration of the redshift distribution of photometric galaxies via cross-correlation with an overlapping spectroscopic survey whose members trace the same density field. We review the theory, develop a pipeline to implement the method, apply it to mock data from N-body simulations, and examine the properties of this redshift distribution estimator. We demonstrate that the method is generally effective, but the estimator is weakened by two main factors. One is that the correlation function of the spectroscopic sample must be measured in many bins along the line of sight, which renders the measurement noisy and interferes with high-quality reconstruction of the photometric redshift distribution. Also, the method is not able to disentangle the photometric redshift distribution from redshift dependence in the bias of the photometric sample. We establish the impact of these factors using our mock catalogs. We conclude that it may still be necessary to spectroscopically follow up a fair subsample of the photometric survey data. Nonetheless, it is significant that the method has been successfully implemented on mock data, and with further refinement it may appreciably decrease the number of spectra that will be needed to calibrate future surveys.

Schulz, A. E., E-mail: schulz@ias.ed [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States)

2010-12-01

256

Common standards of basal insulin titration in type 2 diabetes.  

PubMed

Type 2 diabetes mellitus has become a worldwide major health problem, and the number of people affected is steadily increasing. Thus, not all patients suffering from the disease can be treated by specialized diabetes centers or outpatient clinics, but by primary care physicians. The latter, however, might have time constraints and have to deal with many kinds of diseases or with multimorbid patients, so their focus is not so much on lowering high blood glucose values. Thus, the physicians, as well as the patients themselves, are often reluctant to initiate and adjust insulin therapy, although basal insulin therapy is considered the appropriate strategy after oral antidiabetic drug failure, according to the latest international guidelines. A substantial number of clinical studies have shown that insulin initiation and optimization can be managed successfully by using titration algorithms-even in cases where patients themselves are the drivers of insulin titration. Nevertheless, tools and strategies are needed to facilitate this process in the daily life of both primary health care professionals and patients with diabetes. PMID:23759411

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

2013-05-01

257

On distinguishing age from metallicity with photometric data  

NASA Astrophysics Data System (ADS)

In the study of galaxy integrated light, if photometric indicators could extract age and metallicity information of high enough quality, photometry might be vastly more efficient than spectroscopy for the same astrophysical goals. Towards this end, we search three photometric systems: David Dunlap Observatory, Beijing-Arizona-Taiwan-Connecticut and Strömgren systems for their ability to disentangle age and abundance effects. Only the Strömgren [c1] versus [m1] plot shows moderate age-metallicity disentanglement. We also add to the discussion of optical to near-infrared Johnson-Cousins broad-band colours, finding a great decrease in age sensitivity when updated isochrones are used.

Tang, Baitian; Worthey, Guy

2013-03-01

258

LePHARE: Photometric Analysis for Redshift Estimate  

NASA Astrophysics Data System (ADS)

LePHARE is a set of Fortran commands to compute photometric redshifts and to perform SED fitting. The latest version includes new features with FIR fitting and a more complete treatment of physical parameters and uncertainties based on PEGASE and Bruzual & Charlot population synthesis models. The program is based on a simple chi2 fitting method between the theoretical and observed photometric catalogue. A simulation program is also available in order to generate realistic multi-colour catalogues taking into account observational effects.

Arnouts, S.; Ilbert, O.

2011-08-01

259

Photometric measurements of solar irradiance variations due to sunspots  

SciTech Connect

A photometric telescope constructed to obtain photometric sunspot areas and deficits on a daily basis is described. Data from this Cartesian full disk telescope (CFDT) are analyzed with attention given to the period between June 4 and June 17, 1985 because of the availability of overlapping sunspot area and irradiance deficit data from high-resolution digital spectroheliograms made with the San Fernando Observatory 28 cm vacuum solar telescope and spectroheliograph. The CFDT sunspot deficits suggest a substantial irradiance contribution from faculae and active region plage. 23 refs.

Chapman, G.A.; Herzog, A.D.; Laico, D.E.; Lawrence, J.K.; Templer, M.S. (San Fernando Observatory, El Segundo, CA (USA))

1989-08-01

260

Multi-epoch UBVRI photometric catalog of symbiotic stars  

Microsoft Academic Search

We present a multi-epoch, accurate UBVRcIc photometric catalog of 83\\u000asymbiotic stars and related objects, measured while calibrating the Henden and\\u000aMunari (2000, 2001, 2006) photometric sequences around them. The vast majority\\u000aof the observations where collected in the time interval between October 19,\\u000a1998 to April 21, 2002 with the 1.0-m Ritchey-Chretien telescope of the U. S.\\u000aNaval Observatory,

A. Henden; U. Munari

2009-01-01

261

Multi-wavelength photometric variation of PG 1605+072  

NASA Astrophysics Data System (ADS)

In a large coordinated attempt to further our understanding of the p-mode pulsating sdB star PG 1605+072, the Multi-Site Spectroscopic Telescope (MSST) collaboration has obtained simultaneous time-resolved spectroscopic and photometric observations. The photometry was extended by additional WET data which increased the time base. This contribution outlines the analysis of the MSST photometric light curve, including the four-colour BUSCA data from which chromatic amplitudes have been derived, as well as supplementary FUV spectra and light curves from two different epochs. These results have the potential to complement the interpretation of the published spectroscopic information.

Schuh, S.; Dreizler, S.; Heber, U.; Jeffery, C. S.; O'Toole, S. J.; Cordes, O.; Stahn, T.; Lutz, R.; Tillich, A.; Wet and MSST Collaborations

2008-12-01

262

Exploring the Variable Sky with Linear. 1. Photometric Recalibration with the Sloan Digital Sky Survey.  

National Technical Information Service (NTIS)

We describe photometric recalibration of data obtained by the asteroid survey LINEAR. Although LINEAR was designed for astrometric discovery of moving objects, the data set described here contains over 5 billion photometric measurements for about 25 milli...

A. C. Becker B. Sesar D. P. Morgan J. S. Stuart Z. Ivezic

2011-01-01

263

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

Code of Federal Regulations, 2010 CFR

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

2010-04-01

264

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

Code of Federal Regulations, 2010 CFR

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

2009-04-01

265

Determining Grasp Points Using Photometric Stereo and the PRISM Binocular Stereo System.  

National Technical Information Service (NTIS)

This paper describes a system which locates and grasps doughnut shaped parts from a pile. The system uses photometric stereo and binocular stereo as vision input tools. Photometric stereo is used to make surface orientation measurements. With this informa...

K. Ikeuchi H. K. Nishihara S. Magata B. K. P. Horn P. Sobalvarro

1984-01-01

266

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

267

Efficacy of daytime continuous positive airway pressure titration in severe obstructive sleep apnoea  

Microsoft Academic Search

Efficacy of daytime continuous positive airway pressure titration in severe obstructive sleep apnoea. J.C. Rudkowski, P. Verschelden, R.J. Kimoff. #ERS Journals Ltd 2001. ABSTRACT: The aim of this study was to evaluate manual nasal continuous positive airway pressure (nCPAP) titration during daytime polysomnography compared with conventional overnight titration for patients with severe obstructive sleep apnoea. Thirty-two patients who underwent daytime

J. C. Rudkowski; P. Verschelden; R. J. Kimoff

2001-01-01

268

Formation and calcination temperature-dependent sintering activity of YAG precursor synthesized via reverse titration method  

Microsoft Academic Search

The composition homogeneity of YAG precursors synthesized via both normal and reverse titration co-precipitation methods is discussed. It was demonstrated that that the reverse titration process possesses better co-precipitation characteristics than the normal titration process, based on a real-time monitoring of the reaction pH and measurement of the Y\\/Al ratio in the precipitate. The formation process of the precipitate obtained

Yuanhua Sang; Hong Liu; Xudong Sun; Xiaolin Zhang; Haiming Qin; Yaohui Lv; Di Huo; Duo Liu; Jiyang Wang; Robert I. Boughton

2011-01-01

269

SHARDS: An Optical Spectro-photometric Survey of Distant Galaxies  

NASA Astrophysics Data System (ADS)

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

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

2013-01-01

270

Robust Photometric Invariant Region Detection in Multispectral Images  

Microsoft Academic Search

Our aim is to detect photometric invariant regions in multispectral images robust against sensor noise. Therefore, different polar angle representations of a spectrum are examined for invariance using the dichromatic reflection model. These invariant representations take advantage of white balancing. Based on the camera sensitivity, a theoretical expression is obtained of the certainty associated with the polar angular representations under

Th. Gevers; H. M. G. Stokman

2003-01-01

271

Probable swirls detected as photometric anomalies in Oceanus Procellarum  

Microsoft Academic Search

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

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

2010-01-01

272

Photometric study of a sample of southern binary galaxies  

Microsoft Academic Search

Aims.This work exhibits the basic optical photometric data for a sample of 50 probable southern binary galaxies. Our sample covers a broad range of pair separations, stages of interaction, and morphologies. From the initial list of selected pairs, using spectroscopic data from the literature and our own data, we conclude that 84% of these systems are true binary galaxies. Methods:

T. C. Couto da Silva; R. E. de Souza

2006-01-01

273

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

274

Photometric anomalies of the lunar surface: Results from Clementine data  

NASA Astrophysics Data System (ADS)

We mapped the photometric characteristics of the lunar surface for several small areas using Clementine UVVIS camera images. The maps of the phase function steepness showed several anomalous sites. Several small fresh impact craters have anomalous halos in these maps. The phase function within the halos is less steep than for the surrounding mare surface. We interpret these halos to be due to geologically recent impact-caused alteration of the equilibrium millimeter-scale regolith structure. This equilibrium structure is established through micrometeoritic bombardment at a geologically short timescale. An anomaly of the same signature was found at the Apollo 15 landing site. We interpret it as being a result of the regolith structure alteration with the lander jets. A unique photometric anomaly not correlated with albedo was found within the Reiner Gamma Formation. We suggest that this anomaly is genetically related to the formation, which indicates its young age. This favors the impact hypothesis for the nature of the Reiner Gamma Formation. Our study showed that mapping of photometric characteristics is a new powerful tool in studies of the surfaces of atmosphereless bodies. Future photometric studies of the Moon with existing and new data sets are promising for a search for traces of recent seismic events, studies of the recent population of meteoroids in the inner solar system, an advance in the understanding of swirls, etc.

Kreslavsky, M. A.; Shkuratov, Y. G.

2003-03-01

275

PROTOTYPE CORRELATION MASK FLAME PHOTOMETRIC DETECTOR FOR MEASURING SULFUR DIOXIDE  

EPA Science Inventory

A prototype flame photometric detector system (FPD) to measure gaseous sulfur compounds was fabricated using a previously developed correlation mask optical system and a new flame housing. Also, a new burner for the FPD system was optimized to view the excited molecular sulfur em...

276

Photometric Observations of Asteroid 433 Eros during 2012 Apparition  

NASA Astrophysics Data System (ADS)

A total of 55 clear-filtered photometric observations of the near-Earth asteroid 433 Eros were made on four nights from Holtsville Observatory during the 2012 apparition. The lightcurves were plotted using data from these observations to detect the amplitudes. The amplitudes and also the synodic rotation period of the 2012 apparition in clear-filtered photometry are discussed here.

Melillo, Frank J.

2013-04-01

277

Photometric Period of V1974 Cygni (Nova Cygni 1992).  

National Technical Information Service (NTIS)

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

J. A. DeYoung R. E. Schmidt

1994-01-01

278

Recursive photometric stereo when multiple shadows and highlights are present  

Microsoft Academic Search

We present a recursive algorithm for 3D surface recon- struction based on Photometric Stereo in the presence of highlights, and self and cast shadows. We assume that the surface reflectance outside the highlights can be approxi- mated by the Lambertian model. The algorithm works with as few as three light sources, and it can be generalised for N without any

Vasileios Argyriou; Maria Petrou

2008-01-01

279

Self-Calibration and Neural Network Implementation of Photometric Stereo  

Microsoft Academic Search

This paper describes a new approach to neural network implementation of photometric stereo for a rotational object with non-uniform reflectance factor Three input images are acquired under different conditions of illumination. One illumination direction is chosen to be aligned with the viewing direction. We require no separate calibration object to estimate the associated reflectance maps. Instead, self-calibration is done using

Yuji Iwahori; Yumi Watanabe; Robert J. Woodham; Akira Iwata

2002-01-01

280

Gradient and Curvature from Photometric Stereo Including Local Condence Estimation  

Microsoft Academic Search

Photometric stereo is one technique for 3D shape determination that has been imple- mented in a variety of experimental settings and that has produced consistently good re- sults. The idea is to use intensity values recorded from multiple images obtained from the same viewpoint but under dieren t conditions of illumination. The resulting radiometric constraint makes it possible to obtain

Robert J. Woodham

1994-01-01

281

Simultaneous estimation of shape and reflectance maps from photometric stereo  

Microsoft Academic Search

The authors address the issue of whether the shape of an object and certain parameters of its reflectance map can be jointly estimated using photometric stereo. This problem has been addressed in the literature for the case where the Lambertian and non-Lambertian components in the image can be easily separated. The authors do not assume each separability. They highlight some

Hemant D. Tagare; R. J. P. de Figueiredo

1990-01-01

282

Estimating the Parameters of an Illumination Model Using Photometric Stereo  

Microsoft Academic Search

We investigate the accurate recording of an object's geometric and material properties using photometric stereo. This includes the simultaneous estimation of surface normals and surface reflectance parameters. We assume fairly general reflectance properties, including a combination of diffuse and specular reflection. By applying nonlinear regression techniques to a simplified version of the Torrance-Sparrow model we show how to do the

Greg Kay; Terry Caelli

1995-01-01

283

Dense Photometric Stereo Using a Mirror Sphere and Graph Cut  

Microsoft Academic Search

We present a surprisingly simple system that allows for robust normal reconstruction by dense photometric stereo, in the presence of severe shadows, highlight, transparen- cies, complex geometry, variable light intensity attenuation and inaccurate light directions. Our system consists of a mirror sphere, a spotlight and a DV camera only. Using this, we produce a dense set of unbiased but noisy

Tai-pang Wu; Chi-keung Tang

2005-01-01

284

Adaptive Matching Using Object Models Generated from Photometric Stereo Images  

Microsoft Academic Search

We present a complete object recognition system for 3-D objects using a viewer- centered object description, so-called surface normal images (SNIs), recently introduced by Park et al. (3). Based on this representation we utilize a weak active technique (the Photometric Stereo Method (PSM)) to extract 3-D features from the objects. We combine surface orientations with an approximated line drawing to

Gunter Bellaire; Karsten Schlüns; Arno Mitritz; K. Gwinner

1995-01-01

285

Non-rigid Photometric Stereo with Colored Lights  

Microsoft Academic Search

We present an algorithm and the associated capture methodology to acquire and track the detailed 3D shape, bends, and wrinkles of deforming surfaces. Moving 3D data has been difficult to obtain by methods that rely on known surface features, structured light, or silhouettes. Multi spec- tral photometric stereo is an attractive alternative becau se it can recover a dense normal

Carlos Hernández; George Vogiatzis; Gabriel J. Brostow; Björn Stenger; Roberto Cipolla

2007-01-01

286

Principal components analysis and neural network implementation of photometric stereo  

Microsoft Academic Search

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

Yuji Iwahori; Robert J. Woodham; Ardeshir Bagheri

1995-01-01

287

Reconstruction in the Round Using Photometric Normals and Silhouettes  

Microsoft Academic Search

This paper addresses the problem of obtaining complete, detailed reconstructions of shiny textureless objects. We present an algorithm which uses silhouettes of the object, as well as images obtained under varying illumination con- ditions. In contrast with previous photometric stereo tech- niques, ours is not limited to a single viewpoint and pro- duces accurate reconstructions in full 3D. A number

George Vogiatzis; Carlos Hernández; Roberto Cipolla

2006-01-01

288

Three-dimensional shape from color photometric stereo  

Microsoft Academic Search

Computer vision systems can be used to determine the shapes of real three-dimensional objects for purposes of object recognition and pose estimation or for CAD applications. One method that has been developed is photometric stereo. This method uses several images taken from the same viewpoint, but with different lightings, to determine the three-dimensional shape of an object. Most previous work

Per H. Christensen; Linda G. Shapiro

1994-01-01

289

Shape and Spatially-Varying BRDFs from Photometric Stereo  

Microsoft Academic Search

This paper describes a photometric stereo method designed for surfaces with spatially-varying BRDFs, including sur- faces with both varying diffuse and specular properties. Our method builds on the observation that most objects are composed of a small number of fundamental materials. This approach recovers not only the shape but also material BRDFs and weight maps, yielding compelling results for a

Dan B. Goldman; Brian Curless; Aaron Hertzmann; Steven M. Seitz

2005-01-01

290

Photometric Stereo for Non-Lambertian Surfaces Using Color Information  

Microsoft Academic Search

One robust method to reconstruct shape is photometric stereo (PMS), which reconstructs surface orientation using the Lambertian reflection properties of the surface material. To increase the applicability to non-Lambertian surfaces, we extend this method using a two- stage process without introducing additional light sources or assuming a known micro facet distribution. In the first step, the glossy reflection is discarded,

Karsten Schlfins

1993-01-01

291

Rough surface classification using point statistics from photometric stereo  

Microsoft Academic Search

Rough surfaces can be classified by the point statistics of their derivative fields, estimated using photometric stereo. Such a scheme is proposed and found to be more accurate and robust than image-intensity-based classification. It is particularly effective when applied to directional surfaces, even under rotation. The scheme is therefore robust and economic – suitable for many applications and worthy of

Ged Mcgunnigle; Mike J. Chantler

2000-01-01

292

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

293

The Palomar Transient Factory photometric catalog 1.0  

NASA Astrophysics Data System (ADS)

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

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

2012-08-01

294

Dynamic Shape Capture via Periodical-Illumination Optical Flow Estimation and Multi-view Photometric Stereo  

Microsoft Academic Search

Multi-view photometric stereo is well established for the shape recovery of static objects. However, it is difficult to align motion images under varying illumination so as to perform photometric stereo reconstruction for dynamic objects. To tackle this issue, this paper presents an optical flow estimation approach which works under periodically varying illuminations, and in cooperation with photometric stereo, enables high-quality

Ying Fu; Yebin Liu; Qionghai Dai

2011-01-01

295

Isothermal Titration Calorimetry for Measuring Macromolecule-Ligand Affinity  

PubMed Central

Isothermal titration calorimetry (ITC) is a useful tool for understanding the complete thermodynamic picture of a binding reaction. In biological sciences, macromolecular interactions are essential in understanding the machinery of the cell. Experimental conditions, such as buffer and temperature, can be tailored to the particular binding system being studied. However, careful planning is needed since certain ligand and macromolecule concentration ranges are necessary to obtain useful data. Concentrations of the macromolecule and ligand need to be accurately determined for reliable results. Care also needs to be taken when preparing the samples as impurities can significantly affect the experiment. When ITC experiments, along with controls, are performed properly, useful binding information, such as the stoichiometry, affinity and enthalpy, are obtained. By running additional experiments under different buffer or temperature conditions, more detailed information can be obtained about the system. A protocol for the basic setup of an ITC experiment is given.

Duff, Jr., Michael R.; Grubbs, Jordan; Howell, Elizabeth E.

2011-01-01

296

Revisiting the optimal c value for isothermal titration calorimetry.  

PubMed

The precision with which the dissociation constant, K(D), can be obtained from isothermal titration calorimetry depends on, among other factors, the concentrations of the interacting species. The so-called c value-the ratio of analyte concentration to K(D)-should fall in the range of 1 to 1000 for reliable K(D) determination. On the basis of simulated, noise-free data, Biswas and Tsodikov [5] recently suggested an optimal c value of 5 to 20. By contrast, we find an optimum at c > 40 on determining the K(D) confidence intervals through simulations containing noise levels typical of state-of-the-art microcalorimeters. PMID:21854755

Broecker, Jana; Vargas, Carolyn; Keller, Sandro

2011-07-30

297

Effects of ionic radius of redox-inactive bio-related metal ions on the radical-scavenging activity of flavonoids evaluated using photometric titration.  

PubMed

Mg(2+) enhanced the scavenging activity of (+)-catechin and quercetin against the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH?), while Al(3+) decreased their activity. Such effects of Mg(2+) and Al(3+) were not observed for kaempferol. Na(+) and Ca(2+) with large ionic radii showed little effect on the DPPH?-scavenging activity of these three flavonoids. PMID:24030811

Waki, Tsukasa; Kobayashi, Shigeki; Matsumoto, Ken-Ichiro; Ozawa, Toshihiko; Kamada, Tadashi; Nakanishi, Ikuo

2013-09-26

298

Precision Cosmology with a New Probabilistic Photometric Redshifts Approach  

NASA Astrophysics Data System (ADS)

A complete understanding of both dark energy and dark matter remains one of most important challenges in astrophysics today. Recent theoretical and numerical computations have made important progress in quantifying the role of these dark components on the formation and evolution of galaxies through cosmic time, but observational verification of these predictions and the development of new, more stringent constraints has not kept pace. It is in this context that, photometric redshifts have become more important with the growth of large imaging surveys, such as DES and LSST, that have been designed to address this issue. But their basic implementation has not changed significantly from their original development, as most techniques provide a single photometric redshift estimate and an associated error for the an extragalactic source. In this work, we present a unique and powerful solution that leverages the full information contained in the photometric data to address this cosmological challenge with a new approach that provides accurate photometric redshift probability density functions (PDF) for galaxies. This new approach, which scales efficiently to massive data, efficiently combines standard template fitting techniques with powerful machine learning methods. Included in this framework is our recently developed technique entitled Trees for PhotoZ (TPZ); a new, robust, parallel photometric redshift code that uses prediction trees and random forests to generate photo-z PDFs in a reliable and fast manner. In addition, our approach also provides ancillary information about the internal structure of the data, including the relative importance of variables used during the redshift estimation, an identification of areas in the training sample that provide poor predictions, and an accurate outlier rejection method. We will also present current results of this approach on a variety of datasets and discuss, by using specific examples, how the full photo-z PDF can be incorporated into galaxy clustering analysis enhancing the cosmological measurements, such as the angular power spectrum or the galaxy redshift distribution, to accelerate the cosmological discovery process and improve our knowledge of the Universe.

Carrasco Kind, Matias; Brunner, R. J.

2013-06-01

299

In-flight photometric performance of the 96Mpx focal plane array assembly for NASA's Kepler exoplanet mission  

NASA Astrophysics Data System (ADS)

Kepler is NASA's first space mission dedicated to the study of exoplanets. The primary scientific goal is statistical - to estimate the frequency of planetary systems associated with sun-like stars. Kepler was launched into an Earth-trailing heliocentric "drift-away" orbit in March 2009, and is monitoring 150,000 stars. The instrument detects the faint photometric signals of transits of those systems whose orbital planes are oriented in our line-of-sight. An Earth-Sun analog will produce a transit depth of 80 parts per million (ppm), lasting for at most a few tens of hours, and repeating once per "year". The instrumentation was designed to provide photometric data with a precision of 20 parts per million in 6.5 hours for 12th magnitude stars, resulting in a signal-to-noise ratio of 4 for an Earth-Sun transit. The stability of the flight system enables the precision of the data that reveal subtle instrumental and astrophysical effects that in turn allow a deeper understanding of the performance of the hardware, to enhanced operational procedures, and to novel post-processing of the data. The data are approaching the sensitivity needed to detect transits of terrestrial planets. Intrinsic stellar variability is now the most significant component of the photometric error budget.

Ebbets, D.; Argabright, V.; Stober, J.; Vancleve, J.; Caldwell, D.; Kolodziejczak, J.

2011-09-01

300

Propofol Alone Titrated to Deep Sedation Versus Propofol in Combination with Opioids and\\/or Benzodiazepines and Titrated to Moderate Sedation for Colonoscopy  

Microsoft Academic Search

BACKGROUND:Propofol by nonanesthesiologists is controversial because the drug is commonly used to produce deep sedation or general anesthesia. Propofol in combination with opioids and\\/or benzodiazepines can be titrated to moderate sedation, which might be safer.AIM:To compare recovery time, patient satisfaction, and other end points with propofol alone titrated to deep sedation versus propofol combination therapy with opioids and\\/or benzodiazepines.METHOD:A randomized

Megan E. VanNatta; Douglas K. Rex

2006-01-01

301

Macromolecular competition titration method accessing thermodynamics of the unmodified macromolecule-ligand interactions through spectroscopic titrations of fluorescent analogs.  

PubMed

Analysis of thermodynamically rigorous binding isotherms provides fundamental information about the energetics of the ligand-macromolecule interactions and often an invaluable insight about the structure of the formed complexes. The Macromolecular Competition Titration (MCT) method enables one to quantitatively obtain interaction parameters of protein-nucleic acid interactions, which may not be available by other methods, particularly for the unmodified long polymer lattices and specific nucleic acid substrates, if the binding is not accompanied by adequate spectroscopic signal changes. The method can be applied using different fluorescent nucleic acids or fluorophores, although the etheno-derivatives of nucleic acid are especially suitable as they are relatively easy to prepare, have significant blue fluorescence, their excitation band lies far from the protein absorption spectrum, and the modification eliminates the possibility of base pairing with other nucleic acids. The MCT method is not limited to the specific size of the reference nucleic acid. Particularly, a simple analysis of the competition titration experiments is described in which the fluorescent, short fragment of nucleic acid, spanning the exact site-size of the protein-nucleic acid complex, and binding with only a 1:1 stoichiometry to the protein, is used as a reference macromolecule. Although the MCT method is predominantly discussed as applied to studying protein-nucleic acid interactions, it can generally be applied to any ligand-macromolecule system by monitoring the association reaction using the spectroscopic signal originating from the reference macromolecule in the presence of the competing macromolecule, whose interaction parameters with the ligand are to be determined. PMID:21195223

Bujalowski, Wlodzimierz; Jezewska, Maria J

2011-01-01

302

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

303

The Determination of the Points of Zero Charge of Fine Mineral Particles by a Titration Technique.  

National Technical Information Service (NTIS)

The Bureau of Mines has developed a simple titration technique for determining the points of zero charge (PZC) on minerals. The technique consists of titrating a mineral slurry with the potassium salt of polyvinyl sulfuric acid (PVSK) in the presence of a...

D. A. Stanley P. M. Brown B. J. Scheiner

1982-01-01

304

Estimation of ? and ? peptide bonds in thermal poly(aspartic acid) by potentiometric titration  

Microsoft Academic Search

A potentiometric titration method for the estimation of the configuration (a and ß peptide bonds, I and II) of poly (aspartic acid) prepared by thermal polycondensation is presented. Experimental results of the potentiometric titration of various samples differing in the molar fraction of I and II are confronted with the results of 13C NMR spectroscopy. Both methods lead to comparable

V. Saudek; J. Drobnik

1981-01-01

305

Membrane Surface-Charge Titration Probed by Gramicidin A Channel Conductance  

Microsoft Academic Search

We manipulate lipid bilayer surface charge and gauge its influence on gramicidin A channel conductance by two strategies: titration of the lipid charge through bulk solution pH and dilution of a charged lipid by neutral. Using diphytanoyl phosphatidylserine (PS) bilayers with CsCl aqueous solutions, we show that the effects of lipid charge titration on channel conductance are masked 1) by

Tatiana K. Rostovtseva; Vicente M. Aguilella; Igor Vodyanoy; Sergey M. Bezrukov; V. Adrian Parsegian

1998-01-01

306

CHARACTERIZATION OF ASPHALTENES FROM SAUDI ARABIAN CRUDE OILS BY NONAQUEOUS POTENTIOMETRIC TITRATION AND ELEMENTAL ANALYSIS  

Microsoft Academic Search

Nonaqueous poientiometric titration was employed for the estimation of basic functionalities in the asphaltanes. A series of model basic compounds were titrated in a solvent mixture containing chlorobenzene and acetic anhydride. Perchloric acid in dioxane was used as the titrant. The model basic compounds were classified into very weak bases, weak bases and strong bases, based on their pKa (H2O)

Mohammad FarhatAli; Mohammad Saleem

1994-01-01

307

Sertraline treatment of obsessive-compulsive disorder: efficacy and tolerability of a rapid titration regimen  

Microsoft Academic Search

The objective of this study was to compare in a single blind manner, over a period of 12 weeks, the efficacy and tolerability of two different titration regimens of sertraline in the treatment of OCD: 150 mg\\/day reached at day five from the beginning of therapy (rapid titration regimen) versus 150 mg\\/day reached at day 15 from the beginning (slow

Filippo Bogetto; Umberto Albert; Giuseppe Maina

2002-01-01

308

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

309

Role of different nocturnal monitorings in the evaluation of CPAP titration by autoCPAP devices.  

PubMed

The aim of the study was to assess how the analysis of different signals recorded during application of automatic continuous positive airway pressure (autoCPAP) devices improves the evaluation of pressure titration in patients with obstructive sleep apnea syndrome (OSAS) naive to treatment. Seventy-two patients underwent nocturnal polysomnography during autoCPAP (Autoset T, ResMed, Sydney, Australia) application. Progressively more complex combinations of signals were analysed in consecutive steps. According to the analysis of oxyhemoglobin saturation (SaO(2)) alone, a fixed CPAP level suitable for treatment could not be identified in 3 subjects. When analysis of posture was added, titration was considered unsatisfactory in 1 more subject, due to a short time spent supine. Further, addition of flow and respiratory movements led to consider titration unsatisfactory in 1 more subject. Analysis of all polysomnographic signals demonstrated a not fully reliable titration in 9 subjects: 1 with short sleep duration, 2 without REM sleep, 4 with a short sleep time spent supine, and 3 subjects (already identified by SaO(2)) with insufficient correction of respiratory disorders even when a relatively high CPAP was administered. Mask leaks did not hamper titration. CPAP titration by automatic devices alone results in imperfect titration in >10% subjects naive to ventilatory treatment. Only polysomnographic recording ensures titration reliability in all patients. Further research is needed to identify simple and economic methods to reliably start the CPAP treatment. PMID:15733507

Marrone, Oreste; Insalaco, Giuseppe; Salvaggio, Adriana; Bonsignore, Giovanni

2005-03-01

310

Efficacy of daytime continuous positive airway pressure titration in severe obstructive sleep apnoea.  

PubMed

The aim of this study was to evaluate manual nasal continuous positive airway pressure (nCPAP) titration during daytime polysomnography compared with conventional overnight titration for patients with severe obstructive sleep apnoea. Thirty-two patients who underwent daytime titration were retrospectively matched (for age, sex, body mass index and apnoea/hypopnoea index (AHI)) to a group titrated overnight during the same period. Successful titration was defined as the identification of the nCPAP level (effective nCPAP (Peff)) required to eliminate respiratory events during all sleep stages. After 3 months of therapy on nCPAP at Peff, nCPAP utilization history was obtained and a group of patients underwent a repeat polysomnogram (PSG) and completed a follow-up Epworth Sleepiness Scale (ESS) score. Initial titration was successful in 91% of daytime patients and 91% of overnight patients. The success of daytime titration was not related to diagnostic AHI or ESS score. Subjective nCPAP utilization was statistically similar in both groups. On the follow-up PSG, there were no significant differences between daytime (n=11) and overnight (n=11) patients in measures of sleep quality or respiratory disturbance. Both groups demonstrated similar and significant improvements in ESS score. These findings suggest that the effective nasal continuous positive airway pressure can be accurately established during daytime titration in a substantial proportion of severe, symptomatic obstructive sleep apnoea patients. PMID:11589352

Rudkowski, J C; Verschelden, P; Kimoff, R J

2001-09-01

311

Potentiometric titration of alkyl aromatic sulfonates using a PVC membrane electrode  

Microsoft Academic Search

A potentiometric titration method for determinig high-equivalent-weight sulfonates has been developed. This method utilizes a precipitation reaction between sulfonate and quaternary ammonium ions. A PVC (polyvinyl chloride) membrane electrode, which responds to the quaternary ammonium titrant, signals the end point of the titration. Interferences from inorganic and organic anions have been examined. Compared with the visual Methylene Blue Method, this

S. H. Hoke; A. G. Collins

1979-01-01

312

Coulometric acid-base titration in nanoliter samples with glass and antimony electrodes.  

PubMed

A modification of the coulometric acid-base titration method is described for the measurement of titratable acid and ammonium in nanoliter samples. The main components consist of a pH-seeking device and a miniaturized antimony electrode system capable of delivering OH- ions at a known rate. The modifications include use of a cup-shaped pH-sensitive glass-membrane electrode for monitoring pH changes during titration and a new electronic titration circuit consisting of a high-impedance differential electrometer, a constant-current source, and an electronic integrating circuit. Details regarding the construction of the components of the titration system and practical aspects of its use are also provided. PMID:7058893

Karlmark, B; Jaeger, P; Fein, H; Giebisch, G

1982-01-01

313

Photometric Constraints on Chemical Evolution Models of Irregular Galaxies  

NASA Astrophysics Data System (ADS)

The photometric properties of stellar populations that evolve according to chemical evolution models developed by Carigi, Colin & Peimbert (1999) and Carigi & Peimbert (2001) are explored. The models explain the oxygen abundance and gas mass fraction of the irregular galaxies NGC 1560, I Zw 18, NGC 2366, and a typical irregular galaxy. The photometric predictions narrow down the range of possible chemical evolution models. The observed colors of I Zw 18 require an age of 108 - 109 yr for its dominant population, while an older age of 109 - 1010 yr is preferred for the rest of the galaxy sample. The observed colors are in general, within errors, close to the predicted ones. There is a tendency for the observed (B-V) color to imply higher metallicities at a fixed age than (U-B) (equivalently, (U-B) implies younger ages than (B-V)).

Carigi, L.; Bruzual, G.

314

Joint blind restoration and surface recovery in photometric stereo.  

PubMed

We address the problem of simultaneous estimation of scene structure and restoration of images from blurred photometric measurements. In photometric stereo, the structure of an object is determined by using a particular reflectance model (the image irradiance equation) without considering the blurring effect. What we show is that, given arbitrarily blurred observations of a static scene captured with a stationary camera under different illuminant directions, we still can obtain the structure represented by the surface gradients and the albedo and also perform a blind image restoration. The surface gradients and the albedo are modeled as separate Markov random fields, and a suitable regularization scheme is used to estimate the different fields as well as the blur parameter. The results of the experimentations are illustrated with real as well as synthetic images. PMID:15984479

Joshi, Manjunath V; Chaudhuri, Subhasis

2005-06-01

315

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

316

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

317

Using sparse photometric data sets for asteroid lightcurve studies  

Microsoft Academic Search

With the advent of wide-field imagers, it has become possible to conduct a photometric lightcurve survey of many asteroids simultaneously, either for that single purpose (e.g., Dermawan, B., Nakamura, T., Yoshida, F. [2011]. Publ. Astron. Soc. Japan 63, S555–S576; Masiero, J., Jedicke, R., ?urech, J., Gwyn, S., Denneau, L., Larsen, J. [2009]. Icarus 204, 145–171), or as a part of

Brian D. Warner; Alan W. Harris

2011-01-01

318

The photometric evolution of dissolving star clusters. I. First predictions  

Microsoft Academic Search

The broad-band photometric evolution of unresolved star clusters is calculated in a simplified way, 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 the massive stars reduces their number; (b) tidal effects before cluster-wide mass segregation reduce the mass function homogeneously, i.e.

P. Anders; R. de Grijs

2006-01-01

319

The photometric evolution of dissolving star clusters. I. First predictions  

Microsoft Academic Search

The broad-band photometric evolution of unresolved star clusters is calculated in a simplified way, including the preferential loss of\\u000alow-mass stars due to mass segregation. The stellar mass function of a cluster evolves due to three effects: (a) the evolution of the\\u000amassive stars reduces their number; (b) tidal effects before cluster-wide mass segregation reduce the mass function homogeneously,\\u000ai.e.

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

2006-01-01

320

Photometric recording of transmembrane potential in outer hair cells  

PubMed Central

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

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

2008-01-01

321

Photometric Self-Calibration of a Projector-Camera System  

Microsoft Academic Search

In this paper, we present a method for photometric self- calibration of a projector-camera system. In addition to the input transfer functions (commonly called gamma func- tions), we also reconstruct the spatial intensity fall-off from the center to fringe (commonly called the vignetting effect) for both the projector and camera. Projector-camera sys- tems are becoming more popular in a large

Ray Juang; Aditi Majumder

2007-01-01

322

A Spectroscopic and Photometric Survey of M67 Blue Stragglers  

NASA Astrophysics Data System (ADS)

M67 is an old ( ˜\\ 4 Gy; Dinescu et al. 1995) relatively close (V-MV ˜ 9.7; Dinescu et al. 1995) open cluster that allows us to easily acquire photometric and spectroscopic data. To date there has never been a survey of all the blue straggler stars (BSSs) in any cluster using both spectroscopic and photometric data. We have done this for all but three of the known BSSs of M67. Using the Hobby-Eberly 9.2 m Telescope (HET) and the 2.7 m Harlan J. Smith Telescope we obtained high resolution spectroscopic data for each star and the 1 m telescope at the Mount Laguna Observatory to acquire photometric data. We found radial and rotational velocities as well as photometric temperatures for each star. An interesting trend between color and rotational velocity shows that bluer stars usually have higher velocities. Three stars showing no signs of binarity have been found to have radial velocities unlike the mean radial velocity of M67 ( ˜ 34 km/s) making them most likely non-members of the cluster although proper motion studies give them high probabilities of membership. Abundance analysis has also been done for the reddest BSSs (V-I > 0.555) in order to find other information about each star such as surface gravity, temperature, microturbulance and metallicity. One element in particular, lithium, was scrutinized because it has been theorized that it should remain in the atmospheres of some of the cooler (redder) BSSs. We find absolutely no evidence of lithium in any unquestionable BSS and propose that lithium does not exist in the atmospheres of the BSSs of M67. This work was supported by the National Science Foundation under Grant No. 0243745

Shetrone, M.; Warren, S.; Sandquist, E.

2005-12-01

323

On the Photometric Accuracy of RHESSI Imaging and Spectrosocopy  

Microsoft Academic Search

We compare the photometric accuracy of spectra and images in flares observed with the Ramaty High-Energy Solar Spectroscopic\\u000a Imager (RHESSI) spacecraft. We test the accuracy of the photometry by comparing the photon fluxes obtained in different energy\\u000a ranges from the spectral-fitting software SPEX with those fluxes contained in the images reconstructed with the Clean, MEM,\\u000a MEM-Vis, Pixon, and Forward-fit algorithms.

Markus J. Aschwanden; Thomas R. Metcalf; Säm Krucker; Jun Sato; Andrew J. Conway; Gordon J. Hurford; Edward J. Schmahl

2004-01-01

324

On the Photometric Accuracy of RHESSI Imaging and Spectrosocopy  

Microsoft Academic Search

We compare the photometric accuracy of spectra and images in flares observed with the Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) spacecraft. We test the accuracy of the photometry by comparing the photon fluxes obtained in different energy ranges from the spectral-fitting software SPEX with those fluxes contained in the images reconstructed with the Clean, MEM, MEM-Vis, Pixon, and Forward-fit algorithms.

Markus J. Aschwanden; Thomas R. Metcalf; Säm Krucker; Jun Sato; Andrew J. Conway; G. J. Hurford; Edward J. Schmahl

2004-01-01

325

Resolving handwriting from background printing using photometric stereo  

Microsoft Academic Search

We propose a scheme to resolve handwriting from background printing. The scheme detects the indentations made by the pen in the paper. Photometric stereo is usedto recover the surface; a matched\\/lter andclassi\\/er are usedto detect the stroke ind entation. We assess the e0ect of uniform andtexturedbackground s on the recovery of the stroke andtest the scheme on practical examples. The

Ged Mcgunnigle; Mike J. Chantler

2003-01-01

326

Automated Selection of AGNs from SDSS Photometric Data: Initial Results  

NASA Astrophysics Data System (ADS)

We have applied ClassX, an oblique decision tree classifier optimized for astronomical analysis (McGLynn et al. ApJ, 616, December 1, 2004; Suchkov & Hanisch, ApJ, 612, 437, 2004) to the huge, homogeneous multicolor imaging data base of the Sloan Digital Sky Survey (SDSS), training the software on a subset of ˜ 30,000 SDSS objects whose nature is precisely known via spectroscopy. We find that the software, using photometric data only, correctly classifies a very large fraction of the objects with existing SDSS spectra, both galactic and extragalactic. ClassX also accurately predicts the redshifts of galaxies and active galactic nuclei (AGN) in SDSS. Thus ClassX can probably address most of the highly diverse areas of astronomy addressed by SDSS, and should be especially powerful at accurately recognizing very rare objects solely through their photometric properties. The surface density of AGNs selected by ClassX to r ˜ 19 is in reasonable agreement with that quoted by SDSS. When ClassX is exercised on the photometric data fainter than the SDSS spectroscopic limit, the inferred surface density rises sharply, as expected. We discuss our measurement of the surface density as a function of apparent magnitude, which is unique due to the homogeneity of both SDSS and the classifier. Finally, the ability of the classifier to accurately constrain the redshifts of huge numbers (ultimately ˜ 107) of AGNs in the photometric data base provides new insights into the evolution of the AGN luminosity function with cosmic time. While our results are still very preliminary, it is clear that a very large population of relatively low luminosity AGNs appears in the 0.2 < z < 0.4 range.

Suchkov, A. A.; Hanisch, R. J.; Margon, B.

2004-12-01

327

A Photometric Survey of Centaur and Trans-Neptunian Objects  

Microsoft Academic Search

We present a progress report on our program at the Steward Observatory 1.5-m and 2.3-m telescopes, the NASA Infrared Telescope Facility, and the Kitt Peak National Observatory 4.0-m telescope to carry out a B, V, R, J, H, and K band photometric survey of Centaur and Trans-Neptunian Objects (TNOs). The goals of our program are to: (1) constrain the sizes

S. C. Tegler; W. Romanishin; D. A. Weintraub; U. Fink; R. Fevig

1997-01-01

328

Space-based photometric precision from ground-based telescopes  

Microsoft Academic Search

Ground-based telescopes supported by lidar and spectrophotometric auxiliary instrumentation can attain space-based precision for all-sky photometry, with uncertainties dominated by fundamental photon counting statistics. Earth's atmosphere is a wavelength-, directionally- and time-dependent turbid refractive element for every ground-based telescope, and is the primary factor limiting photometric measurement precision. To correct accurately for the transmission of the atmosphere requires direct measurements

Peter C. Zimmer; John T. McGraw; Mark R. Ackermann; Dean C. Hines; Anthony B. Hull; Lisa Rossmann; Daniel C. Zirzow; Steven W. Brown; Claire E. Cramer; Gerald T. Fraser; Keith R. Lykke; Allan W. Smith; Christopher W. Stubbs; John T. Woodward

2010-01-01

329

Cosmos Photometric Redshifts with 30Bands for 2-deg2  

Microsoft Academic Search

We present accurate photometric redshifts (photo-z) in the 2-deg2 COSMOS field. The redshifts are computed with 30 broad, intermediate, and narrowbands covering the UV (Galaxy Evolution Explorer), visible near-IR (NIR; Subaru, Canada-France-Hawaii Telescope (CFHT), United Kingdom Infrared Telescope, and National Optical Astronomy Observatory), and mid-IR (Spitzer\\/IRAC). A chi2 template-fitting method (Le Phare) was used and calibrated with large spectroscopic samples

O. Ilbert; P. Capak; M. Salvato; H. Aussel; H. J. McCracken; D. B. Sanders; N. Scoville; J. Kartaltepe; S. Arnouts; E. Le Floc'h; B. Mobasher; Y. Taniguchi; F. Lamareille; A. Leauthaud; S. Sasaki; D. Thompson; M. Zamojski; G. Zamorani; S. Bardelli; M. Bolzonella; A. Bongiorno; M. Brusa; K. I. Caputi; C. M. Carollo; T. Contini; R. Cook; G. Coppa; O. Cucciati; S. de la Torre; L. de Ravel; P. Franzetti; B. Garilli; G. Hasinger; A. Iovino; P. Kampczyk; J.-P. Kneib; C. Knobel; K. Kovac; J. F. Le Borgne; V. Le Brun; O. Le Fèvre; S. Lilly; D. Looper; C. Maier; V. Mainieri; Y. Mellier; M. Mignoli; T. Murayama; R. Pellò; Y. Peng; E. Pérez-Montero; A. Renzini; E. Ricciardelli; D. Schiminovich; M. Scodeggio; Y. Shioya; J. Silverman; J. Surace; M. Tanaka; L. Tasca; L. Tresse; D. Vergani; E. Zucca

2009-01-01

330

Near-IR photometric monitoring observations of Nova Oph 2012  

NASA Astrophysics Data System (ADS)

We report on our near-IR photometric monitoring observations of Nova Oph 2012 (PNV J17260708-2551454) from 2012 May to 2013 April. The observations were performed with the 3.8-m United Kingdom Infrared Telescope (UKIRT) and the UKIRT Wide Field Camera (WFCAM), using the near-IR filters Z, Y, J, H and K (effective wavelengths: 0.8717, 1.0305, 1.2483, 1.6313 and 2.2010 microns respectively).

Varricatt, W. P.; Carroll, T.; Ehle, J.; Wold, T.

2013-05-01

331

Photometric recording of transmembrane potential in outer hair cells  

NASA Astrophysics Data System (ADS)

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

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

2006-06-01

332

Design Issues for a Colour Photometric Stereo System  

Microsoft Academic Search

This paper presents the detailed performance analysis for a colour photometric stereo system proposed recently. The system\\u000a recovers surface colour and surface normal for each surface patch separately, in the presence of highlights and shadows. The\\u000a error analysis presented concerns every step of the algorithm, and it is based on the assumptions that errors may arise due\\u000a to Gaussian image

Svetlana Barsky; Maria Petrou

2006-01-01

333

Recovering discontinuous surfaces with photometric stereo and laser sectioning  

NASA Astrophysics Data System (ADS)

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

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

2011-05-01

334

Photometric analysis of RR Lyrae stars. II - T Sextantis  

Microsoft Academic Search

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

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

1991-01-01

335

Flash photometric experiments on the photochemical cycle of bacteriorhodopsin  

Microsoft Academic Search

The photochemical reaction cycle of bacteriorhodopsin was investigated by means of flash photometric methods. Three different intermediates with absorption maxima at about 630 nm, 411 nm, and 646 nm could be detected. Kinetic data of the occurrence of these intermediates were obtained from isolated purple membrane in different mediums and from intact halobacteria. An activation energy of 14.1±0.4 kcal·mol-1 and

N. Dencher; M. Wilms

1975-01-01

336

The Photometric Brightness Variation of Geostationary Orbit Satellite  

NASA Astrophysics Data System (ADS)

Photometric observation is one of the most effective techniques for determining the physical characteristics of unknown space objects and space debris. In this research, we examine the change in brightness of the Communication, Ocean, Meteorological Satellite-1 (COMS-1) Geostationary Orbit Satellite (GEO), and compare it to our estimate model. First, we calculate the maximum brightness time using our calculation method and then derive the light curve shape using our rendering model. The maximum brightness is then calculated using the induced equation from Pogson's formula. For a comparison with our estimation, we carried out photometric observation using an optical telescope. The variation in brightness and the shape of the light curve are similar to the calculations achieved using our model, but the maximum brightness shows a slightly different value from our calculation result depending on the input parameters. This paper examines the photometric phenomenon of the variation in brightness of a GEO satellite, and the implementation of our approach to understanding the characteristics of space objects.

Seo, Haingja; Song, Yongjun; Lee, Yongseok; Oh, Youngseok

2013-09-01

337

Establishment of the NIST flashing-light photometric unit  

NASA Astrophysics Data System (ADS)

There is a need for accurate measurement of flashing lights for the proper maintenance of aircraft anticollision lights. A large variation in the measured intensities of anticollision lights has been a problem, and thus, NIST has undertaken the task to establish flashing-light photometric standards to provide calibration services in this area. A flashing-light photometric unit [lux second, (lx (DOT) s)] has been realized based on the NIST detector-based candela, using four standard photometers equipped with current integrators. Two different approaches have been taken to calibrate these standard photometers: one based on electrical calibration of the current integrator, and the other based on electronic pulsing of a steady-state photometric standard. The units realized using these two independent methods agreed to within 0.2%. The relative expanded uncertainty (k equals 2) of the standard photometers, in the measurement of the white xenon flash, is estimated to be 0.6%. The standard photometers are characterized for temporal response, linearity, and spectral responsivity, to be used for measurement of xenon flash sources of various waveforms and colors. Calibration services have been established at NIST for flashing-light photometers with white and red anticollision lights.

Ohno, Yoshi; Zong, Yuqin

1997-09-01

338

ArborZ: Photometric Redshifts Using Boosted Decision Trees  

NASA Astrophysics Data System (ADS)

Precision photometric redshifts will be essential for extracting cosmological parameters from the next generation of wide-area imaging surveys. In this paper, we introduce a photometric redshift algorithm, ArborZ, based on the machine-learning technique of boosted decision trees. We study the algorithm using galaxies from the Sloan Digital Sky Survey (SDSS) and from mock catalogs intended to simulate both the SDSS and the upcoming Dark Energy Survey. We show that it improves upon the performance of existing algorithms. Moreover, the method naturally leads to the reconstruction of a full probability density function (PDF) for the photometric redshift of each galaxy, not merely a single "best estimate" and error, and also provides a photo-z quality figure of merit for each galaxy that can be used to reject outliers. We show that the stacked PDFs yield a more accurate reconstruction of the redshift distribution N(z). We discuss limitations of the current algorithm and ideas for future work.

Gerdes, David W.; Sypniewski, Adam J.; McKay, Timothy A.; Hao, Jiangang; Weis, Matthew R.; Wechsler, Risa H.; Busha, Michael T.

2010-06-01

339

Photometric Observations of Transiting Planet Candidates With a Small Telescope  

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

340

Multicolor photometric study of M31 globular clusters  

NASA Astrophysics Data System (ADS)

We present the photometry of 30 globular clusters (GCs) and GC candidates in 15 intermediate-band filters covering the wavelength region from ~3000 to ~10000 Å using the archival CCD images of M31 observed as part of the Beijing - Arizona - Taiwan - Connecticut (BATC) Multicolor Sky Survey. We transform these intermediate-band photometric data into the photometry in the standard U BV RI broad-bands. These M31 GC candidates are selected from the Revised Bologna Catalog (RBC V.3.5), and most of these candidates do not have any photometric data. Therefore, the presented photometric data are a supplement to the RBC V.3.5. We find that 4 out of 61 GCs and GC candidates in RBC V.3.5 do not show any signal on the BATC images at their locations. By applying a linear fit of the distribution in the color-magnitude diagram of blue GCs and GC candidates using data from the RBC V.3.5, in this study, we find the “blue-tilt" of blue M31 GCs with a high confidence at 99.95% or 3.47? for the confirmed GCs, and > 99.99% or 4.87? for GCs and GC candidates.

Fan, Zhou; Ma, Jun; Zhou, Xu

2009-09-01

341

Photometric monitoring of the young star Par 1724 in Orion  

NASA Astrophysics Data System (ADS)

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

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

2009-05-01

342

Photometric properties and origin of bulges in SB0 galaxies  

NASA Astrophysics Data System (ADS)

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

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

2005-04-01

343

SED Fitting and Photometric Redshift Estimation: A Joint Analysis  

NASA Astrophysics Data System (ADS)

Spectral Energy Distribution (SED) fitting is a key instrument in understanding the physical properties of galaxies, such as stellar mass, stellar age, dust content, metallicity, and star formation history. Traditionally, when spectroscopic information is not available, the photometric redshifts of galaxies and the SED fitting parameters are evaluated separately, by means of photo-z codes based on empirical templates and SED fitting algorithms based on theoretical templates libraries. We present our implementation of a fast Markov Chain Monte Carlo algorithm, SpeedyMC (Acquaviva et al 2011), to fit photometric redshifts and galaxy properties at the same time. This approach has the obvious advantage that the uncertainty in the photometric redshifts is correctly incorporated in the estimation of the probability distribution functions of the SED fitting parameters. We compare the performance of SpeedyMC in estimating redshifts to that of photo-z codes like EAZY (Brammer et al 2008) and evaluate the impact of using the joint redshift+parameters analysis on different sets of multi-wavelength data.

Acquaviva, Viviana; Raichoor, A.; Gawiser, E. J.

2013-01-01

344

Calibration of LSST Instrumental and Atmospheric Photometric Passbands  

SciTech Connect

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

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

2011-07-06

345

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

346

Photodigitizing procedures  

Microsoft Academic Search

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

P. D. Kilgore; J. H. Gottbrath

1984-01-01

347

Active-site titration of serine proteases using a fluoride ion selective electrode and sulfonyl fluoride inhibitors.  

PubMed

We report a general procedure for the determination of active enzyme concentrations for serine proteases. The method relies on the measurement of fluoride ion released from sulfonyl fluorides upon reaction with the active-site serine using an ion selective electrode. The results have been independently confirmed by amino acid analyses of subtilisins and by spectrofluorometric and spectrophotometric titrations. The minimal enzyme concentration detectable is 1-10 microM protease. The method is insensitive to color and turbidity of the sample and is therefore useful for measuring protease concentration in broth solutions. The active enzyme concentration of subtilisin BPN' from Bacillus amyloliquefaciens determined by titration with phenylmethylsulfonyl fluoride is 25% higher than the concentration determined using the spectrophotometric burst titrant N-trans-cinnamoylimidazole. Analysis of the pre-steady-state burst amplitude and kinetics suggests that the extinction coefficient for the cinnamoyl acyl-enzyme is larger than previously measured and a significant fraction of the enzyme is present as an unproductive ES2 complex. The molar extinction coefficient at 280 nm for subtilisin BPN' is 26.5 mM-1 cm-1 and for subtilisin from Bacillus lentus is 22.5 mM-1 cm-1. PMID:8937565

Hsia, C Y; Ganshaw, G; Paech, C; Murray, C J

1996-11-15

348

A multidimensional approach to the analysis of chemical shift titration experiments in the frame of a multiple reaction scheme.  

PubMed

We present a method for fitting curves acquired by chemical shift titration experiments, in the frame of a three-step complexation mechanism. To that end, we have implemented a fitting procedure, based on a nonlinear least squares fitting method, that determines the best fitting curve using a "coarse grid search" approach and provides distributions for the different parameters of the complexation model that are compatible with the experimental precision. The resulting analysis protocol is first described and validated on a theoretical data set. We show its ability to converge to the true parameter values of the simulated reaction scheme and to evaluate complexation constants together with multidimensional uncertainties. Then, we apply this protocol to the study of the supramolecular interactions, in aqueous solution, between a lanthanide complex and three different model molecules, using NMR titration experiments. We show that within the uncertainty that can be evaluated from the parameter distributions generated during our analysis, the affinities between the lanthanide derivative and each model molecule can be discriminated, and we propose values for the corresponding thermodynamic constants. Copyright © 2013 John Wiley & Sons, Ltd. PMID:23955873

D'Aléo, Anthony; Dumont, Elise; Maury, Olivier; Giraud, Nicolas

2013-08-16

349

Rapid baculovirus titration based on regulatable green fluorescent protein expression in mammalian cells.  

PubMed

Baculovirus is a promising gene delivery vector and can be titrated by constitutive EGFP expression in HeLa cells, which, however, might interfere with target transgene expression and impart cytotoxicity. Here we constructed Bac-ME accommodating egfp under the inducible metallothionein promoter and Bac-MECB harboring an additional BMP-2 gene. Bac-ME effectively transduced HeLa cells with minimal leaky expression, but expressed EGFP robustly upon induction with ZnSO(4), hence allowing for virus titration by transducing HeLa cells with serially diluted virus, subsequent ZnSO(4) induction and flow cytometry analysis of EGFP-positive cells. The titration protocol enabled the generation of discernable titration curves, determination of transducing titers, and discrimination of the transducing abilities of different virus batches. After titration, cell transduction with pre-determined Bac-ME dose revealed consistent transduction efficiency dependence on the dose, regardless of virus batch and cell type. Bac-MECB was similarly titrated by inducible EGFP expression and used to transduce de-differentiated articular chondrocytes without EGFP induction. BMP-2 expression was proportional to the Bac-MECB dose and promoted cartilage-specific matrix synthesis, implicating the potential of Bac-MECB in restoring chondrocyte differentiation. These data confirmed that regulatable EGFP expression enabled rapid, reliable baculovirus titration without interference with subsequent applications. PMID:22112765

Lo, Wen-Hsin; Chen, Chi-Yuan; Yeh, Chia-Ni; Lin, Chin-Yu; Hu, Yu-Chen

2010-08-21

350

Acid–base properties of ion exchangers. I. Optimising of potentiometric titration of ion exchangers exemplified by carboxylic acid resins  

Microsoft Academic Search

The aim of this work was to determined conditions for fast titration the ion exchanger in the one-sample experiment allowing obtaining its equilibrium titration curve. Carboxylic acid ion exchangers KB-4 and Dowex MAC-3 were taken as examples. They were titrated under different conditions with NaOH, KOH and Ba(OH)2. The forward and backward titration of concentrated immersions of finely ground ion

V. S Soldatov; Z. I Sosinovich; T. A Korshunova; T. V Mironova

2004-01-01

351

Multigrid solution of the nonlinear Poisson-Boltzmann equation and calculation of titration curves.  

PubMed Central

Although knowledge of the pKa values and charge states of individual residues is critical to understanding the role of electrostatic effects in protein structure and function, calculating these quantities is challenging because of the sensitivity of these parameters to the position and distribution of charges. Values for many different proteins which agree well with experimental results have been obtained with modified Tanford-Kirkwood theory in which the protein is modeled as a sphere (reviewed in Ref. 1); however, convergence is more difficult to achieve with finite difference methods, in which the protein is mapped onto a grid and derivatives of the potential function are calculated as differences between the values of the function at grid points (reviewed in Ref. 6). Multigrid methods, in which the size of the grid is varied from fine to coarse in several cycles, decrease computational time, increase rates of convergence, and improve agreement with experiment. Both the accuracy and computational advantage of the multigrid approach increase with grid size, because the time required to achieve a solution increases slowly with grid size. We have implemented a multigrid procedure for solving the nonlinear Poisson-Boltzmann equation, and, using lysozyme as a test case, compared calculations for several crystal forms, different refinement procedures, and different charge assignment schemes. The root mean square difference between calculated and experimental pKa values for the crystal structure which yields best agreement with experiment (1LZT) is 1.1 pH units, with the differences in calculated and experimental pK values being less than 0.6 pH units for 16 out of 21 residues. The calculated titration curves of several residues are biphasic. Images FIGURE 8

Oberoi, H; Allewell, N M

1993-01-01

352

Periodate Titration of Fe(II) in Acid Aqueous Solutions: An Environmentally Friendly Redox Reaction for the Undergraduate Laboratory  

Microsoft Academic Search

An environmentally friendly redox laboratory for the determination of Fe(II) in an acid aqueous medium is presented. This laboratory exercise is an appropriate substitute for the traditional dichromate titration, which is environmentally problematic. This titration method uses the periodate ion as the oxidizing agent and yields results which are as accurate as the dichromate titration. Student success rate in quantitative

THOMAS G. DRUMMOND; WILLIAM L. LOCKHART; SPENCER J. SLATTERY; FAROOQ A. KHAN; ANDREW J. LEAVITT

1997-01-01

353

Photometric Calibration of the LASCO-C2 Coronagraph over 14 Years (1996 - 2009)  

NASA Astrophysics Data System (ADS)

We present a photometric calibration of the SOHO/LASCO-C2 coronagraph based on the analysis of all stars down to magnitude V=8 that transited its field of view during the past 14 years of operation (1996 - 2009), extending the previous work of Llebaria, Lamy, and Danjard ( Icarus 182, 281, 2006). The pre-processing of the images incorporates the most recent determination of the evolution of the LASCO-C2 performances. The automatic procedure then analyzes some 260 000 images to detect, locate, and measure those stars. Aperture photometry is performed using four different aperture sizes, and the zero points (ZPs) of the photometric transformations between the LASCO-C2 magnitudes for its orange filter and the standard V magnitudes are determined after introducing a correction for the color of the stars. A new statistical method ("bootstrap") is introduced to assess the confidence intervals of the mean yearly value of the ZPs. The correction for finite aperture required to derive the calibration coefficient for the surface photometry of extended sources is based on the reconstructed image of bright saturated stars and a robust model for the growth curve. The global temporal evolution of the sensitivity of LASCO-C2 is compatible with a continuous decrease at a rate of ? 0.56 % per year. However, it is better described by two separate linear variations with a discontinuity at the time of the loss of SOHO. After the resumption of normal operations in 1999, the linear decrease of the sensitivity amounts to ? 0.35 % per year.

Gardès, B.; Lamy, P.; Llebaria, A.

2013-04-01

354

Precision photometric redshift calibration for galaxy-galaxy weak lensing  

NASA Astrophysics Data System (ADS)

Accurate photometric redshifts are among the key requirements for precision weak lensing measurements. Both the large size of the Sloan Digital Sky Survey (SDSS) and the existence of large spectroscopic redshift samples that are flux-limited beyond its depth have made it the optimal data source for developing methods to properly calibrate photometric redshifts for lensing. Here, we focus on galaxy-galaxy lensing in a survey with spectroscopic lens redshifts, as in the SDSS. We develop statistics that quantify the effect of source redshift errors on the lensing calibration and on the weighting scheme, and show how they can be used in the presence of redshift failure and sampling variance. We then demonstrate their use with 2838 source galaxies with spectroscopy from DEEP2 and zCOSMOS, evaluating several public photometric redshift algorithms, in two cases including a full p(z) for each object, and find lensing calibration biases as low as <1 per cent (due to fortuitous cancellation of two types of bias) or as high as 20 per cent for methods in active use (despite the small mean photoz bias of these algorithms). Our work demonstrates that lensing-specific statistics must be used to reliably calibrate the lensing signal, due to asymmetric effects of (frequently non-Gaussian) photoz errors. We also demonstrate that large-scale structure (LSS) can strongly impact the photoz calibration and its error estimation, due to a correlation between the LSS and the photoz errors, and argue that at least two independent degree-scale spectroscopic samples are needed to suppress its effects. Given the size of our spectroscopic sample, we can reduce the galaxy-galaxy lensing calibration error well below current SDSS statistical errors. Based in part on observations undertaken at the European Southern Observatory (ESO) Very Large Telescope (VLT) under Large Programme 175.A-0839. E-mail: rmandelb@ias.edu (RM); seljak@itp.uzh.ch (US) ‡ Hubble Fellow.

Mandelbaum, R.; Seljak, U.; Hirata, C. M.; Bardelli, S.; Bolzonella, M.; Bongiorno, A.; Carollo, M.; Contini, T.; Cunha, C. E.; Garilli, B.; Iovino, A.; Kampczyk, P.; Kneib, J.-P.; Knobel, C.; Koo, D. C.; Lamareille, F.; Le Fèvre, O.; Le Borgne, J.-F.; Lilly, S. J.; Maier, C.; Mainieri, V.; Mignoli, M.; Newman, J. A.; Oesch, P. A.; Perez-Montero, E.; Ricciardelli, E.; Scodeggio, M.; Silverman, J.; Tasca, L.

2008-05-01

355

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

356

COSMOLOGY WITH PHOTOMETRIC SURVEYS OF TYPE Ia SUPERNOVAE  

SciTech Connect

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

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

2010-02-01

357

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 (Colwell et al. 2007, Thomson et al. 2007). 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 (Salo et al. 2001, Schmidt et al. 2001; see also Schmidt et al. 2009). For example, a selfgravitating system of identical particles with internal density ? half of solid ice, and following the Bridges et al. (1984) elasticity formula, becomes overstable for optical depths ? > 1, forming oscillations in about 100 meter scale. Like self-gravity wakes, with their typical ? 20° trailing pitch angle, overstable oscillations lead to a longitude-dependent brightness of the rings. Due to their axisymmetric nature, the expected longitude of minimum brightness is shifted to ring ansae. However, according to simulations, the axisymmetric oscillations may coexist with the inclined selfgravity wake structures, which can lead to complicated photometric behavior, depending on properties of the simulated system. The overstable systems may also exhibit amplitude modulations (in km-scales), arising from the mutual beating patterns of the basics overstable oscillations. New results of photometric modeling of viscously overstable dynamical simulations systems are reported, related to the above mentioned topics. The Monte Carlo method of Salo and Karjalainen (2003) is used, previously applied to modeling of photometric signatures of selfgravity wakes (Salo et al. 2004, French et al. 2007), scattering properties of propeller stuctures (Sremcevic et al., 2007), and to the intepretation of elevation-angle dependent opposition effect seen in HST data (Salo and French 2010). For example, the possible observable signatures of amplitude modulations are explored.

Salo, H.

2011-10-01

358

Space-based photometric precision from ground-based telescopes  

NASA Astrophysics Data System (ADS)

Ground-based telescopes supported by lidar and spectrophotometric auxiliary instrumentation can attain space-based precision for all-sky photometry, with uncertainties dominated by fundamental photon counting statistics. Earth's atmosphere is a wavelength-, directionally- and time-dependent turbid refractive element for every ground-based telescope, and is the primary factor limiting photometric measurement precision. To correct accurately for the transmission of the atmosphere requires direct measurements of the wavelength-dependent transmission in the direction and at the time that the supported photometric telescope is acquiring its data. While considerable resources have been devoted to correcting the effects of the atmosphere on angular resolution, the effects on precision photometry have largely been ignored. We describe the facility-class lidar that observes the stable stratosphere, and a spectrophotometer that observes NIST absolutely calibrated standard stars, the combination of which enables fundamentally statistically limited photometric precision. This inexpensive and replicable instrument suite provides the lidar-determined monochromatic absolute transmission of Earth's atmosphere at visible and near-infrared wavelengths to 0.25% per airmass and the wavelengthdependent transparency to less than 1% uncertainty per minute. The atmospheric data are merged to create a metadata stream that allows throughput corrections from data acquired at the time of the scientific observations to be applied to broadband and spectrophotometric scientific data. This new technique replaces the classical use of nightly mean atmospheric extinction coefficients, which invoke a stationary and plane-parallel atmosphere. We demonstrate application of this instrument suite to stellar photometry, and discuss the enhanced value of routinely provably precise photometry obtained with existing and future ground-based telescopes.

Zimmer, Peter C.; McGraw, John T.; Ackermann, Mark R.; Hines, Dean C.; Hull, Anthony B.; Rossmann, Lisa; Zirzow, Daniel C.; Brown, Steven W.; Cramer, Claire E.; Fraser, Gerald T.; Lykke, Keith R.; Smith, Allan W.; Stubbs, Christopher W.; Woodward, John T.

2010-07-01

359

Observed and Calculated Normal Color Indices and Indices in Three Photometric Systems  

NASA Astrophysics Data System (ADS)

We estimate the reliability of previously derived normal energy distributions for stars by comparing normal color indices in three photometric systems (W BV R, uvby, and Vilnius) calculated using these distributions with indices derived from photometric observations. Earlier, we used photometric data from W BV R and uvby catalogs to derive normal color indices for these systems not available in the literature, in the form of mean color indices and indices obtained for representative groups of normal, unreddened stars. The results can be used to estimate both the quality of our normal distributions and the reliability of the normal color indices in the three photometric systems considered.

Knyazeva, L. N.; Kharitonov, A. V.

2002-02-01

360

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

361

Potentiometric Titration of Alkyl Aromatic Sulfonates Using a PVC Membrane Electrode.  

National Technical Information Service (NTIS)

A potentiometric titration method for determinig high-equivalent-weight sulfonates has been developed. This method utilizes a precipitation reaction between sulfonate and quaternary ammonium ions. A PVC (polyvinyl chloride) membrane electrode, which respo...

S. H. Hoke A. G. Collins

1979-01-01

362

Determination of the Oxidative Redox Capacity of Aquifer Sediment Material By Spectrochemical Coulometric Titration.  

National Technical Information Service (NTIS)

Methodology was developed for determination of the oxidative redox capacity of aquifer sediment material by the method of spectroelectrochemical coulometric titration. This method involves the measurement of absorbance of sediment particles slurries at th...

J. L. Anderson M. C. Delgado

1996-01-01

363

Photometrically Triggered Keck Spectroscopy of Fermi BL Lacertae Objects  

NASA Astrophysics Data System (ADS)

We report on Keck spectra of 10 Fermi blazars. J0622+3326, previously unobserved, is shown to be a flat-spectrum radio quasar at redshift z = 1.062. The others are known BL Lac type objects that have resisted previous attempts to secure redshifts. Using a photometric monitoring campaign with the 0.76 m Katzman Automatic Imaging Telescope at Lick Observatory, we identified epochs when the relativistic jet emission was fainter than usual, thus triggering the Keck spectroscopy. This strategy gives improved sensitivity to stars and ionized gas in the host galaxy, thereby providing improved redshift constraints for seven of these sources.

Shaw, Michael S.; Filippenko, Alexei V.; Romani, Roger W.; Cenko, S. Bradley; Li, Weidong

2013-11-01

364

The photometric and kinematic structure and asymmetry of disk galaxies  

NASA Astrophysics Data System (ADS)

We establish a sample of 39 nearby, nearly face-on disk galaxies for a detailed study of their photometric and kinematic structure and asymmetries. For this sample we collected two-dimensional Halpha velocity-fields at echelle resolutions with the DensePak integral field unit on the WIYN 3.5m telescope, HI line widths taken with the Nancay radio telescope, and deep R and I-band imaging from the WIYN telescope, the 2.1m telescope at KPNO, and the Harlan J. Smith 2.7m telescope at McDonald Observatory. These data put constraints on the shape of disk galaxies and their halos and are used to study the fundamental disk galaxy scaling relationship between rotation speed and luminosity, i.e., the Tully-Fisher relation. To study the shapes of galaxy disks, we measured both photometric and kinematic asymmetries. From studies of the asymmetry, we were able to show that the now commonly used photometric rotational asymmetry index does not measure disk flocculence as previously suggested; instead it is shown to be equivalent to low order, odd Fourier amplitudes, i.e., lopsidedness. In addition to studying disk lopsidedness, a set of kinematic and photometric indices are used to present the first measurements of disk ellipticity for galaxies outside the Milky Way. These measurements are decoupled from a phase angle which plagues previous estimates of disk ellipticity. Nonetheless, our disk ellipticity measurement of 0.083 +/- 0.054 is consistent with these previous estimates. This measurement allows us to put a limit of 0.15 mag on Tully-Fisher scatter due to the intrinsic ellipticity of disk galaxies. Kinematic inclination angles, one of the primary kinematic indices used to measure disk ellipticity, were derived from model velocity-field fits to our Halpha velocity fields. These inclinations are both accurate and precise and allowed us to create the first Tully-Fisher relation for nearly face-on disk galaxies. We demonstrate that our face-on Tully-Fisher sample is well fit by a published Tully-Fisher relation. In fact, the Tully-Fisher scatter for our data was smaller than that of the parent Tully-Fisher survey. The future of integral field units like SparsePak, newly commissioned on the WIYN telescope, promises more advances in the study of galaxy kinematics.

Andersen, David Roger

2001-09-01

365

An Analysis and Implications of Kepler’s Photometric Uncertainties  

NASA Astrophysics Data System (ADS)

The photometric uncertainties of the Kepler targets carry important information on the intrinsic limitation of the Kepler survey regarding small planets in long-period orbits, precisely the corner of the period-radius diagram where the key information is located on the frequency of terrestrial, habitable-zone planets. An analysis of these uncertainties shows that they can be relatively well approximated by an analytical function, but that there are numerous outliers, both real and artificial. The application to estimating eta-sub-Earth will be shown.

Traub, Wesley A.

2013-10-01

366

Photometric Catalog of the Deep Ecliptic Survey (Buie+, 2011)  

NASA Astrophysics Data System (ADS)

Table 1 provides all the defined calibration field centers along with the date each field was observed. The largest contribution was made by the Lowell Observatory 0.8m telescope, during 2000-2006. Additional contributions were made by the SMARTS 0.9m telescope, the University of Arizona 1.5m Kuiper Telescope, and the Lowell Observatory 1.2m Hall telescope. At all facilities, standard Johnson-Cousins V and R filters were used to collect the raw photometric data. (4 data files).

Buie, M. W.; Trilling, D. E.; Wasserman, L. H.; Crudo, R. A.

2011-08-01

367

Femtosecond broadband fluorescence upconversion spectroscopy: Improved setup and photometric correction  

SciTech Connect

A setup for fluorescence upconversion spectroscopy (FLUPS) is described which has 80 fs temporal response (fwhm) for emission in the spectral range 425-750 nm. Broadband phase matching is achieved with tilted gate pulses at 1340 nm. Background from harmonics of the gate pulse is removed and sensitivity increased compared to previous designs. Photometric calibration of the upconversion process is performed with a set of fluorescent dyes. For Coumarin 153 in methanol the peak position, bandwidth, and asymmetry depending on delay time are reported.

Zhang, X.-X. [Photonics Center, College of Physical Science, Nankai University, Tianjin (China); Department of Chemistry, Humboldt Universitaet zu Berlin (Germany); Wuerth, C.; Resch-Genger, U. [Federal Institute for Materials Research and Testing, Berlin (Germany); Zhao, L. [Photonics Center, College of Physical Science, Nankai University, Tianjin (China); Ernsting, N. P.; Sajadi, M. [Department of Chemistry, Humboldt Universitaet zu Berlin (Germany)

2011-06-15

368

Photometric study of the Moon with SMART-1/AMIE  

NASA Astrophysics Data System (ADS)

The Advanced Moon micro-Imager Experiment (AMIE) onboard the ESA SMART-1 lunar mission performed imaging of the Moon between November 2004 and September 2006, when the mission was ended by crashing the spacecraft into the lunar surface. AMIE was a 1024X1024 pixel miniaturized CCD camera with three colour filters and a panchromatic channel (clear filter). The images are of medium-to-high resolution, e.g. at 300 km pericenter altitude the resolution was 27 m/pix. We selected four different regions on the lunar surface imaged by AMIE for the photometric investigation reported here. These regions were selected so that as large phase angle coverage as possible was available, including the opposition geometry. Each of the regions cover a few hundred square kilometers of the lunar surface and were imaged by AMIE several tens of times. The regions examined include, e.g., Reiner gamma and Oceanus Procellarum near the crater Mairan. We utilized the latest in-flight calibration data available and we also georetrified the images to account for the aspect distortions. For the study reported here, the panchromatic filter was chosen since it is the best calibrated channel at the moment. The data was analyzed by implementing a numerical light scattering model with which we have inverted the regolith porosity and macroscopic surface roughness properties for the target areas. The model computes the bidirectional reflectance function using the geometric-optics approximation from a particulate medium constrained by a self-affine fractal random fields mimicking the regolith-covered lunar surface. Fractal description of the surface roughness is used, since it gives a more realistic way to model the true macroscopic surface roughness than the often used Gaussian correlation-model. Unlike in the previous studies, the azimuthal shadowing effects are taken into account, allowing for a more reliable inversion of surface statistics from images with large phase angles. In addition, we have fitted an empirical photometric function to the data which can be used to perform photometric correction to the images in, e.g., image mosaicking. A comparison with the results from the relevant previous photometric studies of the Moon is given. We end by presenting plans for future studies, especially the possible multi-colour photometry.

Naranen, Jyri; Parviainen, Hannu; Muinonen, Karri; Josset, Jean-Luc; Beauvivre, Stephane; Koschny, Detlef; Foing, Bernard H.; Krieger, Bjoern; Amie Team

369

Building an Automated Telescope with High Photometric Accuracy  

NASA Astrophysics Data System (ADS)

The NFO WebScope is a Web-based observatory which has been in use since 2004 December. The telescope is an 0.6 m Group 128 Cassegrain reflector with a new drive and control system. By optical modifications and appropriate image treatment, we have been able to reach a differential photometric accuracy of about 0.005 mag per observation in work on eclipsing binary stars. In addition, middle school, high school, college, graduate students, and public school teachers use this telescope to conduct their astronomical research projects under a NASA IDEAS grant.

Grauer, Albert D.; Neely, A. William; Lacy, Claud H. Sandberg

2008-09-01

370

Space plasma physics: atmospheric emissions photometric imaging experiment.  

PubMed

The atmospheric emissions photometric imaging experiment was flown on Spacelab 1 to study faint natural and artificial atmospheric emission phenomena. The instrument imaged optical emission in the region 2000 to 7500 angstroms with a television system consisting of two optical channels, one wide-angle and one telephoto. A third optical channel imaged onto the photochathode of a microchannel plate photomultiplier tube that has 100 discrete anodes. A hand-held image intensifier camera with an objective grating permitted spectral analysis of the earth's airglow and the shuttle glow. Preliminary data show magnesium ion emission features in the lower ionosphere as well as the spececraft glow spectrum. PMID:17837937

Mende, S B; Swenson, G R; Clifton, K S

1984-07-13

371

Shape and spatially-varying BRDFs from photometric stereo.  

PubMed

This paper describes a photometric stereo method designed for surfaces with spatially-varying BRDFs, including surfaces with both varying diffuse and specular properties. Our optimization-based method builds on the observation that most objects are composed of a small number of fundamental materials by constraining each pixel to be representable by a combination of at most two such materials. This approach recovers not only the shape but also material BRDFs and weight maps, yielding accurate rerenderings under novel lighting conditions for a wide variety of objects. We demonstrate examples of interactive editing operations made possible by our approach. PMID:20431131

Goldman, Dan B; Curless, Brian; Hertzmann, Aaron; Seitz, Steven M

2010-06-01

372

Dual photometric-conductometric detector for microfluidic chip  

NASA Astrophysics Data System (ADS)

A dual simultaneous photometric-conductometric detector for microfluidic chip is reported. Two different detect methods confocal LIF and moveable C4D were combined together. They shared a common detection cell and could respond simultaneously. The dual detector offered possibility of measurement one analyte in two different ways and was advantageous in analyses of mixtures containing organic and inorganic ions. To improve the separation efficiency, pinch injection was carried out by a series of electrokinetic manipulations. Rhodamine B was used to evaluate the performance of the dual detector. The dual detector had highly sensitivity and could offer simultaneous information.

Shen, Feng; Yu, Yong; Kang, Qi

2008-11-01

373

First photometric study of the eclipsing binary PS Persei  

NASA Astrophysics Data System (ADS)

CCD photometric observations of the eclipsing binary PS Persei (PS Per) were obtained on two consecutive days in 2009. The 2003 version of the Wilson-Devinney code was used to analyze the first complete light curves in the V and R bands. It is found that PS Per is a short-period Algol-type binary with the less massive component completely filling its inner critical Roche lobe. The mass ratio of q = 0.518 and the orbital inclination of i = 89.86° are obtained. In addition, based on all available times of primary light minima, including two new ones, the orbital period has been improved.

Yuan, Jin-Zhao

2011-02-01

374

Recent investigations permitting a new interpretation of the results of the conventional titration of gastric juice  

Microsoft Academic Search

Conclusions  Titration of gastric juice with a dilute alkali to the lemon yellow end-point of Töpfer’s indicator measures not only the\\u000a free hydrochloric acid but the acid combined with the gastric proteins (chlorides and phosphates) and also free phosphoric\\u000a acid. This fact is of importance in interpreting the results of the smaller titration figures (i. e., below 8–10 c.c.) for\\u000a they

Lay Martin

1934-01-01

375

Determination of uranyl ion by potentiometric titration using an uranyl-selective electrode  

Microsoft Academic Search

A potentiometric titration of uranyl ion is described using an uranyl selective electrode based on a membrane containing a complex of UO2-bis[di-4-(1,1,3,3-tetra-methylbutyl)phenyl phosphate] as an ion-exchanger and tritolyl phosphate as a solvent mediator. The titrations were carried out with various titrants: sodium hydroxide, potassium fluoride and sodium salts of acetate, oxalate and citrate. The equivalence points were determined by Gran's

Nabil S. Nassory

1990-01-01

376

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

377

A Rapid Air Titration Method for Determining SO2 Concentration in Inhalation Chambers  

Microsoft Academic Search

A rapid air titration method for determining SO2 concentration in inhalation chambers has been validated using the pararosaniline-formaldehyde (PRA) method of West and Gaeke. This air-titration (iodate) method is an adaptation of iodometric methods using a starch indicator. Potassium iodate and an excess of potassium iodide are used in the reaction. Sampling is completed in ten minutes or less and

EILEEN A. SNYDER; E. D. PALMES

1985-01-01

378

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

Microsoft Academic Search

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

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

2010-01-01

379

ANALYSES BY CONDUCTOMETRIC TITRATION OF CHLORIDES FROM WASTEWATERS THAT CONTAINS HEAVY METALS  

Microsoft Academic Search

SUMMARY The Romanian legislation trough its standards recommend to analyze the chlorides from wastewaters using the method of standard Mohr titration. A very facile and selective method is proposed for fast determination of chloride from wastewaters resulted from galvanization processes, by conductometric titration using AgNO3. The method allows to analyze the chlorides over the range 177.5 ÷ 17750 mg Cl-\\/l

Laura BULGARIU; Brindusa ROBU; Doina BILBA; M. MACOVEANU

380

A New and Sharp Ternary Indicator System for Argentometric Titration of Microamounts of Iodide  

Microsoft Academic Search

.  ?A ternary indicator system, Cadion 1B-silver ion-emulsifier octylphenyl polyglycol ether, for visual and direct titration\\u000a of iodide ion with silver nitrate (as the titrant) is described. The advantages of the method are as follows: (1) when the\\u000a titration reaches the equivalence point, the color of the resulting solution sharply changes from pure yellow to orange and\\u000a the solution remains transparent

Guo-Zhen Fang; Shang-Fen Gao

2001-01-01

381

Effects of cultivation conditions on acid-base titration properties of Shewanella putrefaciens  

Microsoft Academic Search

Acid-base titrations were conducted on pure strain laboratory cultures of the Gram-negative, facultatively aerobic bacterium Shewanella putrefaciens, cultivated under a range of conditions. Bacteria used in acid-base titrations were cultivated for periods of 24 to 100 h (exponential growth phase to late stationary phase), in varying media compositions (rich to minimal), and under aerobic and anaerobic conditions. In addition, two

Johnson R. Haas

2004-01-01

382

Potentiometric titration of long chain quaternary ammonium compounds using sodium tetraphenyl borate  

Microsoft Academic Search

Current methods for determining the activity of long chain quaternary ammonium compounds (QACS) are based either on dye partition,\\u000a titration, or colorimetric analysis. The two major disadvantages of these methods are the disparity of partition coefficients\\u000a among differently constituted QACS and the difficulty in detecting visual end points. Some potentiometric titration methods\\u000a for QACS have been reported in the literature.

C. N. Wanga; L. D. Metcalfea; J. J. Donkerbroek; A. H. M. Cosijn

1989-01-01

383

DETERMINATION OF TECHNETIUM BY CONTROLLED-POTENTIAL COULOMETRIC TITRATION IN BUFFERED SODIUM TRIPOLYPHOSPHATE MEDIUM  

Microsoft Academic Search

A controlled-potential coulometric method for the determination of Tc ; was developed whereby Tc(VII) is titrated in an acetate-buffered (pH 4.7) ; solution of sodium tripolyphosphate at a potential of --0.70 volt vs S.C.E. In ; the range from about 0.5 to 5 mg of Tc(VII) titrated, the relative error of the ; method is about 450 deg C in

A. A. Terry; H. E. Zittel

1963-01-01

384

Efficacy and Tolerability of Rosuvastatin and Atorvastatin when Force-Titrated in Patients with Primary Hypercholesterolemia  

Microsoft Academic Search

Background: Patients at high risk of cardiovascular disease frequently fail to reach recommended low-density lipoprotein cholesterol (LDL-C) goals, partly because statin doses are not titrated to optimal effect. The ECLIPSE study was designed to compare the efficacy and safety of force-titrated treatment with rosuvastatin (10–40 mg) with that of atorvastatin (10–80 mg) in high-risk patients with hypercholesterolemia. Methods: In this

Ole Faergeman; Laurie Hill; Eberhard Windler; Olov Wiklund; Roland Asmar; Emma Duffield; Froukje Sosef

2008-01-01

385

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

386

Photodigitizing procedures  

NASA Astrophysics Data System (ADS)

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

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

1984-02-01

387

Photometric determination of sulfuric acid in ammonium sulfate  

SciTech Connect

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

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

1982-01-01

388

A photometric catalogue of southern emission-line stars  

NASA Astrophysics Data System (ADS)

We present a catalogue of previously unpublished optical and infrared photometry for a sample of 162 emission-line objects and shell stars visible from the southern hemisphere. The data were obtained between 1978 and 1997 in the Walraven (WULBV), Johnson/Cousins (UBV(RI)c) and ESO and SAAO near-infrared (JHKLM) photometric systems. Most of the observed objects are Herbig Ae/Be (HAeBe) stars or HAeBe candidates appearing in the list of HAeBe candidates of Thé et al. (1994), although several B[e] stars, LBVs and T Tauri stars are also included in our sample. For many of the stars the data presented here are the first photo-electric measurements in the literature. The resulting catalogue consists of 1809 photometric measurements. Optical variability was detected in 66 out of the 116 sources that were observed more than once. 15 out of the 50 stars observed multiple times in the infrared showed variability at 2.2 mu m (K band). Based on observations collected at the European Southern Observatory, La Silla, Chile and on observations collected at the South African Astronomical Observatory. Tables 2-4 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http:/ /cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/380/609

de Winter, D.; van den Ancker, M. E.; Maira, A.; Thé, P. S.; Djie, H. R. E. Tjin A.; Redondo, I.; Eiroa, C.; Molster, F. J.

2001-12-01

389

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.

390

Detection of KOI-13.01 Using the Photometric Orbit  

NASA Astrophysics Data System (ADS)

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

Shporer, Avi; Jenkins, Jon M.; Rowe, Jason F.; Sanderfer, Dwight T.; Seader, Shawn E.; Smith, Jeffrey C.; Still, Martin D.; Thompson, Susan E.; Twicken, Joseph D.; Welsh, William F.

2011-12-01

391

On the Photometric Accuracy of RHESSI Imaging and Spectrosocopy  

NASA Astrophysics Data System (ADS)

We compare the photometric accuracy of spectra and images in flares observed with the Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) spacecraft. We test the accuracy of the photometry by comparing the photon fluxes obtained in different energy ranges from the spectral-fitting software SPEX with those fluxes contained in the images reconstructed with the Clean, MEM, MEM-Vis, Pixon, and Forward-fit algorithms. We quantify also the background fluxes, the fidelity of source geometries, and spatial spectra reconstructed with the five image reconstruction algorithms. We investigate the effects of grid selection, pixel size, field of view, and time intervals on the quality of image reconstruction. The detailed parameters and statistics are provided in an accompanying CD-ROM and web page. We find that Forward-fit, Pixon, and Clean have a robust convergence behavior and a photometric accuracy in the order of a few percent, while MEM does not converge optimally for large degrees of freedom (for large field of view and/or small pixel sizes), and MEM-Vis suffers in the case of time-variable sources. This comparative study documents the current status of the RHESSI spectral and imaging software, one year after launch.

Aschwanden, Markus J.; Metcalf, Thomas R.; Krucker, Säm; Sato, Jun; Conway, Andrew J.; Hurford, G. J.; Schmahl, Edward J.

2004-01-01

392

Photometric Properties of the Bright Lenticular Galaxy NGC 5102  

NASA Astrophysics Data System (ADS)

Using the photographic imagery of the SO galaxy NGC 5102, the equivalent luminosity profile and the fractional integrated luminosity curve have been derived. Several photometric parameters of the galaxy, such as a total magnitude (B_T), equivalent radius (r^star_e), effective surface brightness (mu^star_e), and concentration indices (C_21, C_32) were derived from the luminosity profiles. According to the decomposition method from nonlinear least squares fitting, photometric parameters of the bulge (mu_e, r_e) and the exponential disk (mu(0), alpha^-1), and the bulge to total luminosity ratio (B/T) were obtained. The derived central disk surface brightness (mu(0) = 22.06 +- 0.18 mag/*+/- and the evaluated B/T ratio (= 0.52) of the NGC 5102 are close to the mean values (mu(0) = 21.65 +- 0.3 mag/*+/-", B/T = 0.63) of the SO galaxies. Analysis showed that a lens-like hump is embedded in the equivalent luminosity profile of the NGC 5102.

Sohn, Young-Jong; Chun, Mun-Suk; Byun, Yong-Ik

1991-12-01

393

The potential of sparse photometric data in asteroid shape modeling  

NASA Astrophysics Data System (ADS)

We investigate the potential of the sparse data produced by the Catalina Sky Survey astrometric project (CSS for short) in asteroid shape and rotational state determination by the lightcurve inversion method. We show that although the photometric quality of the CSS data, compared to the dense data, is significantly worse, it is in principle possible that these data are for some asteroids with high lightcurve amplitudes sufficient for a unique shape determination. CSS data are available for ˜180 asteroids for which shape models were previously derived from different photometric data sets. For 13 asteroids from this sample, we derive their unique shape models based only on CSS data, compare the two independent shape models together and discuss the reliability of models derived from only CSS data. We also use CSS data to determine shape models for asteroids with already known rotational period values, derive 12 unique models and compare previously published periods with periods determined from the full 3D modeling by the lightcurve inversion method. Finally, we test different shape resolutions used in the lightcurve inversion method in order to find reliable asteroid models.

Hanuš, J.; ?urech, J.

2012-12-01

394

Using Colors to Improve Photometric Metallicity Estimates for Galaxies  

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

395

Photometric Properties of the Variable Star LZ Herculis  

NASA Astrophysics Data System (ADS)

We present BV photometric results of the variable star LZ Her. Frolov & Irkaev classified it as a field SX Phe-type pulsating star, but our observations clearly show that LZ Her is not an SX Phe star, but rather a W UMa-type eclipsing binary, as reported by Garrido et al. The orbital period is derived to be 0.33173646 days by combining our data with that in the literature. The eclipsing light-curve solution from the Wilson-Devinney code shows that LZ Her belongs to the W subgroup of W UMa stars; the primary component is less massive and hotter, with a spectral type of F9-G0, and the secondary is more massive and cooler, with a spectral type G5-G6. The spectral types were estimated from the photometric light-curve solution. Asymmetric light curves could be explained by assuming a cool spot on the secondary star. In the observing field of LZ Her, we found a new eclipsing binary, 2MASS 17500367+2928020, with an orbital period of 0.3056 days.

Kim, Seung-Lee; Lee, Jae Woo; Kim, Chulhee; Lee, Chung-Uk; Kang, Yong Beom; Koo, Jae-Rim

2005-12-01

396

Photometric Precision of Backside-Illuminated CCD Arrays  

NASA Astrophysics Data System (ADS)

Limitations in the photometric precision of CCD arrays are an important consideration for the proposed Kepler mission to detect photometric signatures of extrasolar planetary transits. We have examined a 512x512 delta-doped, thinned, backside-illuminated Reticon CCD under controlled laboratory conditions simulating those expected for the Kepler mission. The CCD is mounted on a micropositioning stage to simulate pointing errors aboard the spacecraft. Due to delta-doping, no UV flooding is necessary for its operation and the QE is stable. An LED illuminates a perforated plate, focusing a star pattern on the CCD at a focal ratio of f/8. The entire system is contained in a temperature-controlled enclosure to ensure mechanical stability. Images are read out every 3 sec with 2.5 s exposures and 0.5 s readout time. No shutter is used and the CCD is illuminated continuously. Each frame is the sum of 45 individual images, and each star is approximately 7 pixels wide, resulting in 5.4x10(8) e(-) per star per frame. The flux from each star is normalized by the sum of the fluxes of the other stars, and is then corrected for motion and nonlinear CCD response as per Robinson et al (1994). We repeatably obtain an average systematic error contribution to the total precision of 7x10(-6) at a flux of 10(10) e(-) , demonstrating that systematic CCD errors will not seriously affect the Kepler mission.

Jenkins, J. M.; McDonald, J. S.; Borucki, W. B.; Dunham, E. W.

1996-09-01

397

Photometric Redshift and Classification for the XMM-COSMOS Sources  

NASA Astrophysics Data System (ADS)

We present photometric redshifts and spectral energy distribution (SED) classifications for a sample of 1542 optically identified sources detected with XMM in the COSMOS field. Our template fitting classifies 46 sources as stars and 464 as nonactive galaxies, while the remaining 1032 require templates with an active galactic nucleus (AGN) contribution. High accuracy in the derived photometric redshifts was accomplished as the result of (1) photometry in up to 30 bands with high-significance detections, (2) a new set of SED templates, including 18 hybrids covering the far-UV to mid-infrared, which have been constructed by the combination of AGNs and nonactive galaxies templates, and (3) multiepoch observations that have been used to correct for variability (most important for type 1 AGNs). The reliability of the photometric redshifts is evaluated using the subsample of 442 sources with measured spectroscopic redshifts. We achieved an accuracy of ? _{? z/(1+z_spec)} = 0.014 for i* AB < 22.5 (? _{? z/(1+z_spec)} ˜ 0.015 for i* AB < 24.5). The high accuracies were accomplished for both type 2 (where the SED is often dominated by the host galaxy) and type 1 AGNs and QSOs out to z = 4.5. The number of outliers is a large improvement over previous photometric redshift estimates for X-ray-selected sources (4.0% and 4.8% outliers for i* AB < 22.5 and i* AB < 24.5, respectively). We show that the intermediate band photometry is vital to achieving accurate photometric redshifts for AGNs, whereas the broad SED coverage provided by mid-infrared (Spitzer/IRAC) bands is important to reduce the number of outliers for normal galaxies. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc. (AURA) under NASA contract NAS 5-26555. Also based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under NASA contract 1407. Also based on data collected at: the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan; the XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA member states and NASA; the European Southern Observatory under Large Program 175.A-0839, Chile; Kitt Peak National Observatory, Cerro Tololo Inter-American Observatory and the National Optical Astronomy Observatory, which are operated by AURA under cooperative agreement with the National Science Foundation; and the Canada-France-Hawaii Telescope with MegaPrime/MegaCam operated as a joint project by the CFHT Corporation, CEA/DAPNIA, the NRC and CADC of Canada, the CNRS of France, TERAPIX and the University of Hawaii.

Salvato, M.; Hasinger, G.; Ilbert, O.; Zamorani, G.; Brusa, M.; Scoville, N. Z.; Rau, A.; Capak, P.; Arnouts, S.; Aussel, H.; Bolzonella, M.; Buongiorno, A.; Cappelluti, N.; Caputi, K.; Civano, F.; Cook, R.; Elvis, M.; Gilli, R.; Jahnke, K.; Kartaltepe, J. S.; Impey, C. D.; Lamareille, F.; Le Floc'h, E.; Lilly, S.; Mainieri, V.; McCarthy, P.; McCracken, H.; Mignoli, M.; Mobasher, B.; Murayama, T.; Sasaki, S.; Sanders, D. B.; Schiminovich, D.; Shioya, Y.; Shopbell, P.; Silverman, J.; Smol?i?, V.; Surace, J.; Taniguchi, Y.; Thompson, D.; Trump, J. R.; Urry, M.; Zamojski, M.

2009-01-01

398

Long-range nature of the interactions between titratable groups in Bacillus agaradhaerens family 11 xylanase: pH titration of B. agaradhaerens xylanase.  

PubMed

Xylanase from Bacillus agaradhaerens belongs to a large group of glycosyl hydrolases which catalyze the degradation of xylan. The protonation behavior of titratable groups of the uniformly (15)N- and (13)C-labeled xylanase was investigated by multinuclear NMR spectroscopy. A total of 224 chemical shift titration curves corresponding to (1)H, (13)C, and (15)N resonances revealed pK(a) values for all aspartic and glutamic acid residues, as well as for the C-terminal carboxylate and histidine residues. Most of the titratable groups exhibit a complex titration behavior, which is most likely due to the mutual interactions with other neighboring groups or due to an unusual local microenvironment. Subsite -1 containing the catalytic dyad shows a long-range interaction over 9 A with Asp21 via two hydrogen bonds with Asn45 as the mediator. This result illuminates the pivotal role of the conserved position 45 among family 11 endoxylanases, determining an alkaline pH optimum by asparagine residues or an acidic pH optimum by an aspartate. The asymmetric interactions of neighboring tryptophan side chains with respect to the catalytic dyad can be comprehended as a result of hydrogen bonding and aromatic stacking. Most of the chemical shift-pH profiles of the backbone amides exhibit biphasic behavior with two distinct inflection points, which correspond to the pK(a) values of the nearby acidic side chains. However, the alternation of both positive and negative slopes of individual amide titration curves is interpreted as a consequence of a simultaneous reorganization of side chain conformational space at pH approximately 6 and/or an overall change in the hydrogen network in the substrate binding cleft. PMID:15134456

Betz, Marco; Löhr, Frank; Wienk, Hans; Rüterjans, Heinz

2004-05-18

399

Photometric and spectroscopic gamma-ray observations of solar transient phenomena using long duration balloons  

Microsoft Academic Search

A program currently in progress to conduct extended duration spectroscopic and photometric observation of solar X-ray phenomena from balloons is described. High photometric sensitivity to weak hard X-ray bursts is attained using a 600 sq cm array of phoswich scintillators. High spectral resolution for stronger bursts is available from an array of planar germanium detectors. These instruments are carried in

M. R. Pelling; F. Duttweiler; R. F. Lin; W. K. Levedahl; H. Primbach; D. W. Curtis; K. C. Burley

1985-01-01

400

Automatic planning of light source and camera placement for an active photometric stereo system  

Microsoft Academic Search

An automatic planning method of light source and camera placement for an active photometric stereo system is presented. Since photometric stereo systems normally use multiple light sources fixed to the environment, they cannot avoid shadows caused by surrounding objects. Using a movable light source and adapting its placement actively to the task environment eliminates shadows. Candidate positions for light source

Shigeyuki SAKANE; T. Sato

1991-01-01

401

Appearance Characterization of Linear Lambertian Objects, Generalized Photometric Stereo, and Illumination-Invariant Face Recognition  

Microsoft Academic Search

Traditional photometric stereo algorithms employ a Lambertian reflectance model with a varying albedo field and involve the appearance of only one object. In this paper, we generalize photometric stereo algorithms to handle all appearances of all objects in a class, in particular the human face class, by making use of the linear Lambertian property. A linear Lambertian object is one

Shaohua Kevin Zhou; Gaurav Aggarwal; Rama Chellappa; David W. Jacobs

2007-01-01

402

Automatic planning of light source placement for an active photometric stereo system  

Microsoft Academic Search

Presents an automatic planning method of light source placement for an active photometric stereo system. Since photometric stereo systems normally use multiple light sources fixed to the environment, they cannot avoid shadows caused by surrounding objects. One remedy for this situation is to use a movable light source and to adapt its placement actively to the task environment. Candidate positions

Shigeyuki SAKANE; Tomomasa SATO; Masayoshi KAKIKURA

1990-01-01

403

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

404

Dissecting Photometric Redshift for Active Galactic Nucleus Using XMM- and Chandra-COSMOS Samples  

Microsoft Academic Search

In this paper, we release accurate photometric redshifts for 1692 counterparts to Chandra sources in the central square degree of the Cosmic Evolution Survey (COSMOS) field. The availability of a large training set of spectroscopic redshifts that extends to faint magnitudes enabled photometric redshifts comparable to the highest quality results presently available for normal galaxies. We demonstrate that morphologically extended,

M. Salvato; O. Ilbert; G. Hasinger; A. Rau; F. Civano; G. Zamorani; M. Brusa; M. Elvis; C. Vignali; H. Aussel; A. Comastri; F. Fiore; E. Le Floc'h; V. Mainieri; S. Bardelli; M. Bolzonella; A. Bongiorno; P. Capak; K. Caputi; N. Cappelluti; C. M. Carollo; T. Contini; B. Garilli; A. Iovino; S. Fotopoulou; A. Fruscione; R. Gilli; C. Halliday; J.-P. Kneib; Y. Kakazu; J. S. Kartaltepe; A. M. Koekemoer; K. Kovac; Y. Ideue; H. Ikeda; C. D. Impey; O. Le Fevre; F. Lamareille; G. Lanzuisi; J.-F. Le Borgne; V. Le Brun; S. Lilly; C. Maier; S. Manohar; D. Masters; H. McCracken; H. Messias; M. Mignoli; B. Mobasher; T. Nagao; R. Pello; S. Puccetti; E. Perez-Montero; A. Renzini; M. Sargent; D. B. Sanders; M. Scodeggio; N. Scoville; P. Shopbell; J. Silvermann; Y. Taniguchi; L. Tasca; L. Tresse; J. R. Trump; E. Zucca

2011-01-01

405

Comparison of USGS and DLR topographic models of Comet Borrelly and photometric applications  

Microsoft Academic Search

Stereo analysis of images obtained during the 2001 flyby of Comet Borrelly by NASA's Deep Space 1 (DS1) probe allows us to quantify the shape and photometric behavior of the nucleus. The shape is complex, with planar facets corresponding to the dark, mottled regions of the surface whereas the bright, smooth regions are convexly curved. The photometric as well as

Randolph L Kirk; Elpitha Howington-Kraus; Laurence A Soderblom; Bernd Giese; Jürgen Oberst

2004-01-01

406

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

407

Gusev Photometric Variability as Seen from the Orbit by HRSC/Mars-Express: Contribution of the Opposition Effect  

NASA Astrophysics Data System (ADS)

The multi-angular HRSC dataset generated with the nadir-looking, stereo and photometric channels, is used to derive the surface photometric characteristics for mapping the variation of the soil/bedrock physical properties within Gusev crater.

Pinet, P. C.; Jehl, A.; Daydou, Y. D.; Chevrel, S.; Baratoux, D.; Heuripeau, F.; Manaud, N.; Cord, A.; Hoffmann, H.; Gwinner, K.; Scholten, F.; Roatsch, T.; Neukum, G.; Mars-Express HRSC Co-I Team

2008-03-01

408

Dense photometric stereo: a Markov random field approach.  

PubMed

We address the problem of robust normal reconstruction by dense photometric stereo, in the presence of complex geometry, shadows, highlight, transparencies, variable attenuation in light intensities, and inaccurate estimation in light directions. The input is a dense set of noisy photometric images, conveniently captured by using a very simple set-up consisting of a digital video camera, a reflective mirror sphere, and a handheld spotlight. We formulate the dense photometric stereo problem as a Markov network and investigate two important inference algorithms for Markov Random Fields (MRFs)--graph cuts and belief propagation--to optimize for the most likely setting for each node in the network. In the graph cut algorithm, the MRF formulation is translated into one of energy minimization. A discontinuity-preserving metric is introduced as the compatibility function, which allows alpha-expansion to efficiently perform the maximum a posteriori (MAP) estimation. Using the identical dense input and the same MRF formulation, our tensor belief propagation algorithm recovers faithful normal directions, preserves underlying discontinuities, improves the normal estimation from one of discrete to continuous, and drastically reduces the storage requirement and running time. Both algorithms produce comparable and very faithful normals for complex scenes. Although the discontinuity-preserving metric in graph cuts permits efficient inference of optimal discrete labels with a theoretical guarantee, our estimation algorithm using tensor belief propagation converges to comparable results, but runs faster because very compact messages are passed and combined. We present very encouraging results on normal reconstruction. A simple algorithm is proposed to reconstruct a surface from a normal map recovered by our method. With the reconstructed surface, an inverse process, known as relighting in computer graphics, is proposed to synthesize novel images of the given scene under user-specified light source and direction. The synthesis is made to run in real time by exploiting the state-of-the-art graphics processing unit (GPU). Our method offers many unique advantages over previous relighting methods and can handle a wide range of novel light sources and directions. PMID:17063687

Wu, Tai-Pang; Tang, Kam-Lun; Tang, Chi-Keung; Wong, Tien-Tsin

2006-11-01

409

Quantitative analysis of dimethyl titanocene by iodometric titration, gas chromatography and NMR.  

PubMed

In this study we report the use of an automated iodometric titration method and a novel gas chromatography (GC) method for the quantitative analysis of dimethyl titanocene (DMT), a key raw material in drug synthesis. Both approaches are based on the reaction of DMT in toluene or tetrahydrofuran solutions with iodine. In the case of iodometric titration, excess iodine is titrated with a standardized aqueous sodium thiosulfate solution to a potentiometric end-point for the determination of DMT concentration. Alternatively, GC is employed to measure the concentration of iodomethane, a product of the reaction between DMT and iodine, in order to determine the concentration of DMT in the solution. Excellent agreement between iodometric titration, GC and NMR results using several DMT samples confirms the accuracy of the two methods and strongly supports the use of either method as a replacement to the expensive NMR for quantitative DMT analysis. The relatively few sources of error associated with the two methods, their ubiquitous nature and ease of application in routine analysis make them the analytical methods of choice, among all. Both methods have been validated according to ICH requirements. The use of iodometric titration method for DMT analysis is demonstrated with a couple of applications. PMID:11377038

Vailaya, A; Wang, T; Chen, Y; Huffman, M

2001-06-01

410

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

411

A Probabilistic Approach to Classifying Supernovae UsingPhotometric Information  

SciTech Connect

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

Kuznetsova, Natalia V.; Connolly, Brian M.

2006-12-14

412

Two photometric periods in the AM CVn system CP Eridani  

NASA Astrophysics Data System (ADS)

We report photometric periodicities in the AM CVn system CP Eridani (CP Eri) of 1716.2 ± 0.2 and 1701.4 ± 0.2 s, obtained while the system was in quiescence. From a second observation obtained during superoutburst, we interpret the 1716-s signal as a superhump period (Psh) and the 1701-s signal as the orbital period (Porb) of the binary. The derived fractional superhump period excess ? adds CP Eri to a small collection of AM CVn stars with ? measured via time-series photometry of superhump and orbital periods. Plotting ?(Porb) for these systems, we find that AM CVn systems may, as expected, be evolving towards longer Porb. We discuss a technique of using ? to determine the degree of degeneracy of the donor star in a contact binary, and we show that for the AM CVn systems, the donor stars are well described by mass-radius relations of partially-degenerate objects.

Armstrong, E.; Patterson, J.; Kemp, J.

2012-04-01

413

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

414

First CCD UBVI photometric analysis of six open cluster candidates  

NASA Astrophysics Data System (ADS)

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

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

2011-04-01

415

A photometric and spectrographic study of XX Cygni  

NASA Astrophysics Data System (ADS)

Photometric and spectrographic observations of the RRs variable star XX Cygni are presented. Photometry was obtained in the ubvy beta system by a sky-compensating photometer attached to a 61-cm reflecting telescope. The star is found to have a large light amplitude (0.77 magnitude in V), a reddening of 0.025 magnitude and a small m1 value, indicating low metal content, with a mean effective surface gravity of 3.34 and temperature of 7250 K. Single-trail spectrograms obtained by a 5-m telescope and a coude spectrograph in the wavelength range 3900-4800 A reveal a radial velocity range of 34 km/sec and a mean radial velocity of -110 km/sec, and are consistent with a low metallicity.

McNamara, D. H.; Feltz, K. A., Jr.

1980-04-01

416

A LARGE AND FAINT PHOTOMETRIC CATALOG ON THE ECLIPTIC  

SciTech Connect

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{sup 0} 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 {approx}19 but the largest fraction fall in the R {approx}15-16 (V {approx}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. [Southwest Research Institute, 1050 Walnut St., Suite 300, Boulder, CO 80302 (United States); Trilling, David E. [Department of Physics and Astronomy, Northern Arizona University, Flagstaff, AZ (United States); Wasserman, Lawrence H. [Lowell Observatory, 1400 W. Mars Hill Rd., Flagstaff, AZ 86001 (United States); Crudo, Richard A., E-mail: buie@boulder.swri.edu, E-mail: david.trilling@nau.edu, E-mail: lhw@lowell.edu, E-mail: rcrudo@gmail.com [George Washington University Law School, George Washington University (United States)

2011-06-01

417

The Aquarius Superclusters. II. Spectroscopic and Photometric Data  

NASA Astrophysics Data System (ADS)

We present spectroscopic and photometric data for 920 galaxies selected in 68 fields of the Aquarius Cluster Catalog. Typically, the 15 brightest candidate members with magnitudes in the range 16

Caretta, César A.; Maia, Marcio A. G.; Willmer, Christopher N. A.

2004-12-01

418

Wavelet-constrained stereo matching under photometric variations  

NASA Astrophysics Data System (ADS)

We propose a new method to address the problem of stereo matching under varying illumination conditions. First, a spatially varying multiplicative model is developed to account for photometric changes induced between both images in the stereo pair. The stereo matching problem based on this model is then formulated as a constrained optimization problem in which an appropriate convex objective function is minimized under convex constraints. These constraints arise from prior knowledge and rely on various properties of both disparity and illumination fields. In order to obtain a smooth disparity field while preserving discontinuities around object edges, we consider an appropriate wavelet-based regularization constraint. The resulting multi-constrained optimization problem is solved via an efficient block iterative algorithm which offers great flexibility in the incorporation of several constraints. Experimental results demonstrate the efficiency of the proposed method to recover illumination changes and disparity map simultaneously, making stereo matching very robust w.r.t. such changes.

Miled, Wided; Pesquet, Jean-Christophe; Parent, Michel

2008-05-01

419

Photometric stereo applied to diffuse surfaces that violate Lambert's law.  

PubMed

This paper investigates the use of photometric stereo (PS) with reflectance functions that are diffuse but not Lambertian. We show that, for the special case where light sources are arranged at 90° intervals around the optical axis, standard PS is not limited to Lambertian surfaces, and we define criteria for its use. A series of rough test surfaces are used as models for surface microstructure-we found that the Oren Nayar (ON) reflectance model accurately predicted the surfaces' reflectance functions. The ON model does not meet our theoretical criteria for using PS, but PS performs well in simulations if the microroughness is moderate (rms slope <0.3). When PS was applied to real surfaces, the estimated and actual slopes were highly correlated, but there were significant errors in the slope estimates for the rougher samples. PMID:22472842

McGunnigle, G; Dong, Junyu; Wang, Xuefang

2012-04-01

420

A Multicolor Photometric Study of Three Type I Seyfert Galaxies  

NASA Astrophysics Data System (ADS)

We present CCD observations of three Type I Seyfert galaxies (Akn 120, Mrk 509, and Akn 564) obtained with the SARA 0.9-m telescope during the period May 2001 to September 2002. Variations of a few tenths of a magnitude were observed for all three objects; each exhibits a correlation between brightness (V) and color (V-R). The galaxy Akn 564 exhibits an anomalous color pattern. It consistently appears brightest in the R band and slightly fainter in I and V; the flux in the B filter is significantly depressed. This may result from anomalous internal reddening; alternatively, published magnitudes for comparison stars in the Akn 564 field may be in error. Revised magnitudes for comparison stars in all three fields were derived from analysis of residuals in the photometric solutions of the images. This work is supported by National Science Foundation grant AST-0097616 and by faculty development and research grants from Valdosta State University.

McGregor, S. L.; Rumstay, K. S.

2002-12-01

421

New Asteroid Shape Models Derived from the Lowell Photometric Database  

NASA Astrophysics Data System (ADS)

Asteroid shapes and spin states can be derived from their disk-integrated sparse-in-time photometry by the lightcurve inversion method. A huge amount of sparse photometry is provided by current all-sky surveys. However, the data from surveys suffer from large random and systematic errors. Oszkiewicz et al. (2011, JQSRT 112, 1919) partly removed the systematic trends in the photometry reported to the MPC and created the so-called 'Lowell photometric database'. The database consists of re-calibrated photometry for about 500,000 asteroids, with typically hundreds of brightness measurements per object. Bowell et al. (M&PS, submitted) used this database to analyze brightness variations with ecliptic longitude and estimated spin-axis longitudes for about 350,000 asteroids. In our work, we processed data for the first 10,000 numbered asteroids with the lightcurve inversion method (Kaasalainen et al., 2001, Icarus 153,37) using an enormous computational power of Asteroids@home (http://asteroidsathome.net) - a distributed computing project built on the BOINC platform. More than 10,000 users have joined the project and their computers were used for the time-consuming search for the sidereal rotation period in the sparse data. Although the photometric accuracy of the Lowell data is low 0.2 mag), we were able to find unique models for several hundred asteroids. We will present the first results based on the statistical analysis of the sample (distribution of spin vectors, for example) and we will also discuss the relevance of our approach to Gaia, LSST, ATLAS, and other future sources of asteroid photometry with sparse sampling.

Durech, Josef; Hanus, J.; Vanco, R.; Oszkiewicz, D.; Bowell, E.

2013-10-01

422

Photometric study of the IC 65 group of galaxies  

NASA Astrophysics Data System (ADS)

Context: A large fraction of stellar mass is found to be located in groups the size of the Local Group. The evolutionary status of poor groups is not yet clear and many groups could still be at an early dynamical stage or even still forming, especially the groups only containing spiral and irregular galaxies. Aims: We carried out a photometric study of a poor group of late-type galaxies around IC 65 (a) to search for new dwarf members and to measure their photometric characteristics, (b) to search for possible effects of mutual interactions on the morphology and star-formation characteristics of luminous and faint group members, and (c) to evaluate the evolutionary status of this particular group. Methods: We made use of our BRI CCD observations, DPOSS blue and red frames, and the 2MASS JHK frames. In addition, we used the H I imaging data, the far-infrared, and radio data from the literature. A search for dwarf galaxies was made using the SExtractor software. Detailed surface photometry was performed with the MIDAS package. Results: Four LSB galaxies were classified as probable dwarf members of the group and the BRI physical and model parameters were derived for the first time for all true and probable group members. Newly-found dIrr galaxies around the IC 65 contain a number of H II regions, which show a range of ages and propagating star-formation. Mildly disturbed gaseous and/or stellar morphology is found in several group members. Conclusions: Various structural, dynamical, and star-forming characteristics lead us to conclude that the IC 65 group is a typical poor assembly of late-type galaxies at an early stage of its dynamical evolution with some evidence of intragroup (tidal) interactions. Based on observations obtained at the Calar Alto observatory, Almeria, Spain. Figures 5, 7, 9, Tables 2, 6, 7 and appendices are only available in electronic form at http://www.aanda.org

Vennik, J.; Hopp, U.

2008-04-01

423

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

424

Simultaneous Photometric and Spectroscopic Observations of Young Solar Analogs  

NASA Astrophysics Data System (ADS)

This poster will present some preliminary results, focusing on the relationship between chromospheric activity level and stellar brightness, from our long-term monitoring campaign conducting simultaneous spectroscopic and photometric observations of young stellar analogs (YSAs). Since 2007 we have been conducting spectroscopic monitoring of the Ca II H & K lines for a sample of 31 YSAs in order to better understand their activity cycles and variations, as well as the effects of young stars on their solar systems. The targets cover the spectral range of stars most likely to contain Earth analogs, F8-K2, and a broad enough range of ages, 0.3 Gyr - 1.5 Gyr, to investigate how activity level changes with stellar age. These studies are already showing possible evidence for activity cycles, large variations in starspot activity, and flaring events. In order to obtain a more complete picture of the nature of the stars' activity and examine the correlations between stellar brightness and chromospheric activity, we recently began simultaneous photometric observations of the stars in Johnson B, V and R. Some stars, such as the Sun, show a positive correlation with brightness and activity level. Yet the Lowell Observatory SSS project showed that many G0-G2 type YSAs show a negative correlation. Of particular interest for our project is the determination of which stars show either a positive or negative correlation and characterizing how this changes with stellar age. Results from the first season of observations are presented here. Starting this year we will be adding two new instruments to provide improved temporal coverage and additional data in Stromgren v and H?. Support provided by the NSF.

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

2012-05-01

425

Strömgren photometric survey in the Galactic anticenter direction  

NASA Astrophysics Data System (ADS)

Aims: The main purpose is to map the radial variation of the stellar space density for the young stellar population in the Galactic anticenter direction in order to understand the structure and location of the Perseus spiral arm. Methods: A uvbyH? Strömgren photometric survey covering 16 deg2 in the anticenter direction was carried out using the Wide Field Camera at the Isaac Newton Telescope. This is the natural photometric system for identifying young stars and obtaining accurate estimates of individual distances and ages. The calibration to the standard system was undertaken using open clusters. Results: We present a main catalog of 35 974 stars with all Strömgren indexes and a more extended one with 96 980 stars with partial data. The central 8 deg2 have a limiting magnitude of V ~ 17m, while the outer region reaches V ~ 15.m5. These large samples will permit us to analyze the stellar surface density variation associated to the Perseus arm also to study the properties of the stellar component and the interstellar extinction in the anticenter direction. Final catalog and catalog with individual measurements are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/549/A78Based on observations made with the Isaac Newton Telescope operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias.

Monguió, M.; Figueras, F.; Grosbøl, P.

2013-01-01

426

Systematic trends in Sloan Digital Sky Survey photometric data  

NASA Astrophysics Data System (ADS)

We investigate the Sloan Digital Sky Survey (SDSS) photometry from Data Release 8 (DR8) in the search for systematic trends that still exist after the calibration effort of Padmanabhan et al. We consider both the aperture and point spread function (PSF) magnitudes in DR8. Using the objects with repeat observations, we find that a large proportion of the aperture magnitudes suffer an ˜0.2-2 per cent systematic trend as a function of PSF full width at half-maximum (FWHM), the amplitude of which increases for fainter objects. Analysis of the PSF magnitudes reveals more complicated systematic trends of similar amplitude as a function of PSF FWHM and object brightness. We suspect that sky oversubtraction is the cause of the largest amplitude trends as a function of PSF FWHM. We also detect systematic trends as a function of subpixel coordinates for the PSF magnitudes with peak-to-peak amplitudes of ˜1.6 and ˜4-7 mmag for the over- and undersampled images, respectively. We note that the systematic trends are similar in amplitude to the reported ˜1 and ˜2 per cent precision of the SDSS photometry in the griz and u wavebands, respectively, and therefore their correction has the potential to substantially improve the SDSS photometric precision. We provide an IDL program specifically for this purpose. Finally, we note that the SDSS aperture and PSF magnitude scales are related by a non-linear transformation that departs from linearity by ˜1-4 per cent, which, without correction, invalidates the application of a photometric calibration model derived from the aperture magnitudes to the PSF magnitudes, as has been done for SDSS DR8.

Bramich, D. M.; Freudling, W.

2012-08-01

427

Fair Procedures.  

ERIC Educational Resources Information Center

These materials are part of the Project Benchmark series designed to teach secondary students about our legal concepts and systems. This unit focuses on individual rights and fair procedures under the law. The materials outline the Bill of Rights, due process guarantees, the right to a fair hearing, fair and unfair trials, search and seizure laws,…

Eaneman, Paulette S.; And Others

428

Spectroscopic versus photometric metallicities: Milky Way dwarf spheroidal companions as a test case  

NASA Astrophysics Data System (ADS)

Aims: The method of deriving photometric metallicities using red giant branch stars is applied to resolved stellar populations under the common assumption that they mainly consist of single-age old stellar populations. We explore the effect of the presence of mixed-age stellar populations on deriving photometric metallicities. Methods: We use photometric data sets for the five Galactic dwarf spheroidals Sculptor, Sextans, Carina, Fornax, and Leo II in order to derive their photometric metallicity distribution functions from their resolved red giant branches using isochrones of the Dartmouth Stellar Evolutionary Database. We compare the photometric metallicities with published spectroscopic metallicities based on the analysis of the near-infrared Ca triplet (Ca T), both on the metallicity scale of Carretta & Gratton and on the scale defined by the Dartmouth isochrones. In addition, we compare the photometric metallicities with published spectroscopic metallicities based on spectral synthesis and medium-resolution spectroscopy, and on high resolution spectra where available. Results: The mean properties of the spectroscopic and photometric metallicity samples are comparable within the intrinsic scatter of each method although the mean metallicities of dSphs with pronounced intermediate-age population fractions may be underestimated by the photometric method by up to a few tenths of dex in [Fe/H]. The star-by-star differences of the spectroscopic minus the photometric metallicities show a wide range of values along the fiducial spectroscopic metallicity range, with the tendency to have systematically lower photometric metallicities for those dwarf spheroidals with a higher fraction of intermediate-age populations. Such discrepancies persist even in the case of the purely old Sculptor dSph, where one would naïvely expect a very good match when comparing with medium or low resolution metallicity measurements. Overall, the agreement between Ca T metallicities and photometric metallicities is very good in the metallicity range from ~ -2 dex to ~ -1.5 dex. We find that the photometric method is reliable in galaxies that contain small (less than 15%) intermediate-age stellar fractions. Therefore, in the presence of mixed-age stellar populations, one needs to quantify the fraction of the intermediate-age stars in order to assess their effect on determining metallicities from photometry alone. Finally, we note that the comparison of spectroscopic metallicities of the same stars obtained with different methods reveals similarly large discrepancies as the comparison with photometric metallicities.

Lianou, S.; Grebel, E. K.; Koch, A.

2011-07-01

429

Introducing titratable water to all-atom molecular dynamics at constant pH.  

PubMed

Recent development of titratable coions has paved the way for realizing all-atom molecular dynamics at constant pH. To further improve physical realism, here we describe a technique in which proton titration of the solute is directly coupled to the interconversion between water and hydroxide or hydronium. We test the new method in replica-exchange continuous constant pH molecular dynamics simulations of three proteins, HP36, BBL, and HEWL. The calculated pKa values based on 10-ns sampling per replica have the average absolute and root-mean-square errors of 0.7 and 0.9 pH units, respectively. Introducing titratable water in molecular dynamics offers a means to model proton exchange between solute and solvent, thus opening a door to gaining new insights into the intricate details of biological phenomena involving proton translocation. PMID:23972860

Chen, Wei; Wallace, Jason A; Yue, Zhi; Shen, Jana K

2013-08-20

430

Acid-Base Titration of (S)-Aspartic Acid: A Circular Dichroism Spectrophotometry Experiment  

NASA Astrophysics Data System (ADS)

The magnitude of the circular dichroism of (S)-aspartic acid in aqueous solutions at a fixed wavelength varies with the addition of strong base. This laboratory experiment consists of the circular dichroism spectrophotometric acid-base titration of (S)-aspartic acid in dilute aqueous solutions, and the use of the resulting data to determine the ionization constant of the protonated amino group. The work familiarizes students with circular dichroism and illustrates the possibility of performing titrations using a less usual instrumental method of following the course of a reaction. It shows the use of a chiroptical property in the determination of the concentration in solution of an optically active molecule, and exemplifies the use of a spectrophotometric titration in the determination of an ionization constant.

Cavaleiro, Ana M. V.; Pedrosa de Jesus, Júlio D.

2000-09-01

431

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

432

Potentiometric titrations of Bacillus subtilis cells to low pH and a comparison of modeling approaches  

Microsoft Academic Search

To provide constraints on the speciation of bacterial surface functional groups, we have conducted potentiometric titrations using the gram-positive aerobic species Bacillus subtilis, covering the pH range 2.1 to 9.8. Titration experiments were conducted using an auto-titrator assembly, with the bacteria suspended in fixed ionic strength (0.01 to 0.3 M) NaClO4 solutions. We observed significant adsorption of protons over the

Jeremy B. Fein; Jean-François Boily; Nathan Yee; Drew Gorman-Lewis; Benjamin F. Turner

2005-01-01

433

On Hapke photometric model predictions on reflectance of closely packed particulate surfaces  

NASA Astrophysics Data System (ADS)

In a recent paper Hapke et al. (Hapke, B., Shepard, M., Nelson, R., Smythe, W., Piatek, J. [2009]. Icarus 199, 210-218) performed bi-directional reflectance measurements on closely-packed particulate surfaces of micrometer-sized particles and compared these with both the Hapke IMSA photometric model, and a numerical radiative transfer algorithm, the MDYZ (Mishchenko, M., Dlugach, J., Yanovitskij, E., Zakharova, N. [1999a]. J. Quant. Spectrosc. Radiat. Trans. 63, 409-432). To account for the effects of close packing, Hapke et al. applied a diffraction truncation scheme to remove the diffraction spike and supplied the renormalized single scattering phase function to the IMSA. They found that the IMSA prediction is a better match with measurement than that of MDYZ. In this work we demonstrate that the diffraction truncation procedure outlined by Hapke et al. contains an error. By following Hapke et al.'s intended truncation scheme, we have found that the IMSA model is not sufficiently anisotropic to describe the reflectance pattern of measurements on surface reflectance of closely packed large spherical particles.

Zhang, Hao; Voss, Kenneth J.

2011-09-01

434

Simultaneous Fitting of Orbital Elements and Doppler Imaging of Spots Using Photometric and Spectroscopic Data  

NASA Astrophysics Data System (ADS)

We briefly review previous work on Doppler and photometric imaging of starspot distributions on close binary stars, particularly contact binaries. Difficulties involving standard spherical and cylindrical surface element distributions for imaging are discussed. The method of geodesic distribution binary synthesis (GDDSYN) is faster and more accurate for such work. The Maximum Entropy regularisation method has been extended to include simultaneous photometry and spectroscopy. A further extension allows auxiliary parameters such as mass ratio and fill-out to be determined, as well as the radial velocity amplitude. The spectrum of third light contamination is also obtained, using theoretical spectrum synthesis for the binary as input. Accurate distances act as a powerful constraint on the fitting process. The procedure has been applied by PDH to the system VW Cephei. The development of spots over a two year period has been studied. The fraction of the surface covered by spots appears to be be very large. Future developments will be discussed. This type of approach is essential to obtain good models for cool, heavily-spotted binary systems.

Mochnacki, S. W.; Hendry, P. D.

1997-05-01

435

Fitting isochrones to open cluster photometric data. III. Estimating metallicities from UBV photometry  

NASA Astrophysics Data System (ADS)

The metallicity is a critical parameter that affects the correct determination of fundamental characteristics of a stellar cluster and has important implications in Galactic and stellar evolution research. Fewer than 10% of the 2174 currently cataloged open clusters have their metallicity determined in the literature. In this work we present a method for estimating the metallicity of open clusters via non-subjective isochrone fitting using the cross-entropy global optimization algorithm applied to UBV photometric data. The free parameters distance, reddening, age, and metallicity simultaneously determined by the fitting method. The fitting procedure uses weights for the observational data based on the estimation of membership likelihood for each star, which considers the observational magnitude limit, the density profile of stars as a function of radius from the center of the cluster, and the density of stars in multi-dimensional magnitude space. We present results of [Fe/H] for nine well-studied open clusters based on 15 distinct UBV data sets. The [Fe/H] values obtained in the ten cases for which spectroscopic determinations were available in the literature agree, indicating that our method provides a good alternative to determining [Fe/H] by using an objective isochrone fitting. Our results show that the typical precision is about 0.1 dex. Appendix is available in electronic form at http://www.aanda.org

Oliveira, A. F.; Monteiro, H.; Dias, W. S.; Caetano, T. C.

2013-09-01

436

Titration of free hydroxyl and strained siloxane sites on silicon dioxide with fluorescent probes.  

PubMed

A technique enabling the detection and quantification of low density sites on planar SiO2 surfaces is demonstrated. Fluorescent probes are used to titrate free hydroxyl and strained siloxane sites on the surface of amorphous SiO2 substrates in vacuum. The titration of free hydroxyl sites was performed to validate the method and to provide a reference for the measurement of the strained siloxane site density. Perylene derivatives with different functional groups are chemisorbed onto the surface sites, enabling in situ photoluminescence (PL) measurements of the bound fluorophores. An amine functional group is used to selectively titrate strained siloxane sites, while an alcohol group is used for the titration of free hydroxyl sites. Emission intensity was found to be nonlinear with coverage for bound fluorophore densities greater than 0.1 nm(-2), necessitating the removal of molecules from the surface into a solution to obtain accurate density measurements. For lower densities, the coverage of bound fluorophores can be estimated directly from in situ PL measurements. The measured areal densities of bound fluorophores after titrating free hydroxyl sites are in good agreement with literature values for the densities of such sites on high surface area silica. PL measurements of SiO2 surfaces titrated with an amine derivative of perylene indicate that strained siloxane sites exist for vacuum pretreatment temperatures of 300 °C and increase with increasing pretreatment temperature. Densities of strained siloxane sites on the silica surface are estimated at 0.004-0.02 nm(-2) for pretreatment temperatures of 300-700 °C, demonstrating the sensitivity of this technique. PMID:23978272

McCrate, Joseph M; Ekerdt, John G

2013-09-11

437

Effect of a Titration Polysomnogram on Treatment Success with a Mandibular Repositioning Appliance  

PubMed Central

Study Objectives: Mandibular repositioning appliance (MRA) therapy is a treatment option for patients with mild to moderate sleep apnea and for patients who do not tolerate continuous positive airway pressure. Titration of MRAs consists of sequential mandibular advancement guided by symptom improvement. The goal of the study was to determine if patients with an elevated apnea hypopnea index (AHI), despite the use of a subjectively optimized MRA, could achieve better results with additional titration during polysomnography (PSG). Methods: Patients were enrolled if they had an AHI ? 15/h and were referred for MRA therapy. The MRA was advanced until symptoms improved. During the PSG, the technologist monitored the patient's sleep and increased mandibular protrusion until the AHI was improved. Results: There was a significant improvement in AHI, minimum oxygen saturation, and total sleep time with the MRA before further advancement. At the final PSG, 65.2% of patients had an AHI ? 10 associated with at least a 50% reduction in AHI. The incomplete responders had their appliance further titrated, and this improved the results of MRA therapy by 30.4% to a total success rate of 95.6%. Conclusions: This study shows that it is possible to improve the results of MRA therapy by further advancing the appliance during a titration PSG in patients with an incomplete response. The titration night improved the results of the usual clinical advancement of the MRA with substantially more patients achieving a successful outcome. Citation: Almeida FR; Parker JA; Hodges JS; Lowe AA, Ferguson KA. Effect of a Titration Polysomnogram on Treatment Success with a Mandibular Repositioning Appliance. J Clin Sleep Med 2009;5(3):198-204.

Almeida, Fernanda R.; Parker, Jonathan A.; Hodges, James S.; Lowe, Alan A.; Ferguson, Kathleen A.

2009-01-01

438

A Photometric redshift galaxy catalog from the Red-Sequence Cluster Survey  

SciTech Connect

The Red-Sequence Cluster Survey (RCS) provides a large and deep photometric catalog of galaxies in the z' and R{sub c} bands for 90 square degrees of sky, and supplemental V and B data have been obtained for 33.6 deg{sup 2}. They compile a photometric redshift catalog from these 4-band data by utilizing the empirical quadratic polynomial photometric redshift fitting technique in combination with CNOC2 and GOODS/HDF-N redshift data. The training set includes 4924 spectral redshifts. The resulting catalog contains more than one million galaxies with photometric redshifts < 1.5 and R{sub c} < 24, giving an rms scatter {delta}({Delta}z) < 0.06 within the redshift range 0.2 < z < 0.5 and {sigma}({Delta}z) < 0.11 for galaxies at 0.0 < z < 1.5. They describe the empirical quadratic polynomial photometric redshift fitting technique which they use to determine the relation between red-shift and photometry. A kd-tree algorithm is used to divide up the sample to improve the accuracy of the catalog. They also present a method for estimating the photometric redshift error for individual galaxies. They show that the redshift distribution of the sample is in excellent agreement with smaller and much deeper photometric and spectroscopic redshift surveys.

Hsieh, Bau-Ching; /Taiwan, Natl. Central U. /Taipei, Inst. Astron. Astrophys.; Yee, H.K.C.; /Toronto U., Astron. Dept.; Lin, H.; /Fermilab; Gladders, M.D.; /Carnegie Inst. Observ.

2005-02-01

439

Monitoring of an RNA Multistep Folding Pathway by Isothermal Titration Calorimetry  

PubMed Central

Abstract Isothermal titration calorimetry was used to monitor the energetic landscape of a catalytic RNA, specifically that of the hepatitis delta virus ribozyme. Using mutants that isolated various tertiary interactions, the thermodynamic parameters of several ribozyme-substrate intermediates were determined. The results shed light on the impact of several tertiary interactions on the global structure of the ribozyme. In addition, the data indicate that the formation of the P1.1 pseudoknot is the limiting step of the molecular mechanism. Last, as illustrated here, isothermal titration calorimetry appears to be a method of choice for the elucidation of an RNA's folding pathway.

Reymond, Cedric; Bisaillon, Martin; Perreault, Jean-Pierre

2009-01-01

440

The influence of hydrogen peroxide and pH on the Mohr titration.  

PubMed

The official Japanese method for determination of chloride in hot-spring waters requires any H(2)S present to be oxidized with hydrogen peroxide in ammoniacal medium. When this was done, and the solution was titrated with silver nitrate at pH 9.7, the indicator colour changed from yellow to brownish grey, owing to reduction of silver ions to the metal by hydrogen peroxide. The effect can be eliminated by adjusting the pH to 7.0-7.5 before the titration. PMID:18965181

Fujita, R

1991-05-01

441

Peritonectomy procedures.  

PubMed Central

OBJECTIVE: New surgical procedures designed to assist in the treatment of peritoneal surface malignancy were sought. BACKGROUND: Decisions regarding the treatment of cancer depend on the anatomic location of the malignancy and the biologic aggressiveness of the disease. Some patients may have isolated intra-abdominal seeding of malignancy of limited extent or of low biologic grade. In the past, these clinical situations have been regarded as lethal. METHODS: The cytoreductive approach may require six peritonectomy procedures to resect or strip cancer from all intra-abdominal surfaces. RESULTS: These are greater omentectomy-splenectomy; left upper quadrant peritonectomy; right upper quadrant peritonectomy; lesser omentectomy-cholecystectomy with stripping of the omental bursa; pelvic peritonectomy with sleeve resection of the sigmoid colon; and antrectomy. CONCLUSIONS: Peritonectomy procedures and preparation of the abdomen for early postoperative intraperitoneal chemotherapy were described. The author has used the cytoreductive approach to achieve long-term, disease-free survival in selected patients with peritoneal carcinomatosis, peritoneal sarcomatosis or mesothelioma. Images Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. Figure 8. Figure 9. Figure 10. Figure 11. Figure 12. Figure 13.

Sugarbaker, P H

1995-01-01

442

Estimation of Surface Normal Vector Based on Majority Voting using Multi-Light Photometric Stereo  

NASA Astrophysics Data System (ADS)

In this paper, we present an algorithm for estimating surface normal vectors of object from images using multi-light source photometric stereo method in the presence of highlights and shadows. The conventional three-light photometric stereo can not deal with specularity and shadowing because of its simple assumption of a Lambertian surface and local shading. By high intensity or low intensity values, the specular reflection and shadowing will produce an incorrect surface normal in the traditional photometric stereo. We propose a new strategy to eliminate the effects of specularity and shadowing using an algorithm of majority voting in the multi-light source photometry.

Fukumoto, Hisao; Terashima, Hiroshi; Ohchi, Masashi; Furukawa, Tatsuya

443

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

444

KEPLER INPUT CATALOG: PHOTOMETRIC CALIBRATION AND STELLAR CLASSIFICATION  

SciTech Connect

We describe the photometric calibration and stellar classification methods used by the Stellar Classification Project to produce the Kepler Input Catalog (KIC). The KIC is a catalog containing photometric and physical data for sources in the Kepler mission field of view; it is used by the mission to select optimal targets. Four of the visible-light (g, r, i, z) magnitudes used in the KIC are tied to Sloan Digital Sky Survey magnitudes; the fifth (D51) is an AB magnitude calibrated to be consistent with Castelli and Kurucz (CK) model atmosphere fluxes. We derived atmospheric extinction corrections from hourly observations of secondary standard fields within the Kepler field of view. For these filters and extinction estimates, repeatability of absolute photometry for stars brighter than magnitude 15 is typically 2%. We estimated stellar parameters {l_brace}T{sub eff}, log (g), log (Z), E{sub B-V}{r_brace} using Bayesian posterior probability maximization to match observed colors to CK stellar atmosphere models. We applied Bayesian priors describing the distribution of solar-neighborhood stars in the color-magnitude diagram, in log (Z), and in height above the galactic plane. Several comparisons with samples of stars classified by other means indicate that for 4500 K {<=}T{sub eff} {<=} 6500 K, our classifications are reliable within about {+-}200 K and 0.4 dex in log (g) for dwarfs, with somewhat larger log (g) uncertainties for giants. It is difficult to assess the reliability of our log (Z) estimates, but there is reason to suspect that it is poor, particularly at extreme T{sub eff}. Comparisons between the CK models and observed colors are generally satisfactory with some exceptions, notably for stars cooler than 4500 K. Of great importance for the Kepler mission, for T{sub eff} {<=} 5400 K, comparison with asteroseismic results shows that the distinction between main-sequence stars and giants is reliable with about 98% confidence. Larger errors in log (g) occur for warmer stars, for which our filter set provides inadequate gravity diagnostics. The KIC is available through the MAST data archive.

Brown, Timothy M. [Las Cumbres Observatory Global Telescope, Goleta, CA 93117 (United States); Latham, David W.; Esquerdo, Gilbert A. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Everett, Mark E., E-mail: tbrown@lcogt.net, E-mail: latham@cfa.harvard.edu, E-mail: gesquerd@cfa.harvard.edu, E-mail: everett@noao.edu [National Optical Astronomy Observatories, Tucson, AZ 85721 (United States)

2011-10-15

445

Kepler Input Catalog: Photometric Calibration and Stellar Classification  

NASA Astrophysics Data System (ADS)

We describe the photometric calibration and stellar classification methods used by the Stellar Classification Project to produce the Kepler Input Catalog (KIC). The KIC is a catalog containing photometric and physical data for sources in the Kepler mission field of view; it is used by the mission to select optimal targets. Four of the visible-light (g, r, i, z) magnitudes used in the KIC are tied to Sloan Digital Sky Survey magnitudes; the fifth (D51) is an AB magnitude calibrated to be consistent with Castelli & Kurucz (CK) model atmosphere fluxes. We derived atmospheric extinction corrections from hourly observations of secondary standard fields within the Kepler field of view. For these filters and extinction estimates, repeatability of absolute photometry for stars brighter than magnitude 15 is typically 2%. We estimated stellar parameters {T eff, log (g), log (Z), E B - V } using Bayesian posterior probability maximization to match observed colors to CK stellar atmosphere models. We applied Bayesian priors describing the distribution of solar-neighborhood stars in the color-magnitude diagram, in log (Z), and in height above the galactic plane. Several comparisons with samples of stars classified by other means indicate that for 4500 K <=T eff <= 6500 K, our classifications are reliable within about ±200 K and 0.4 dex in log (g) for dwarfs, with somewhat larger log (g) uncertainties for giants. It is difficult to assess the reliability of our log (Z) estimates, but there is reason to suspect that it is poor, particularly at extreme T eff. Comparisons between the CK models and observed colors are generally satisfactory with some exceptions, notably for stars cooler than 4500 K. Of great importance for the Kepler mission, for T eff <= 5400 K, comparison with asteroseismic results shows that the distinction between main-sequence stars and giants is reliable with about 98% confidence. Larger errors in log (g) occur for warmer stars, for which our filter set provides inadequate gravity diagnostics. The KIC is available through the MAST data archive.

Brown, Timothy M.; Latham, David W.; Everett, Mark E.; Esquerdo, Gilbert A.

2011-10-01

446

Photometric properties of galaxy populations in group and cluster environments  

NASA Astrophysics Data System (ADS)

Using four-band photometric redshifts we explore photometric properties of galaxy populations in group and cluster environments at 0.20 ? z < 0.60. We probe red galaxy fractions (fred) using samples of 76 galaxy clusters and ˜ 1, 200 galaxy groups from CNOC1 and RCS follow-up observations. Within all environments where both local galaxy density and cluster-centric radius are controlled, we observe galaxy downsizing in star formation, as evidenced by the larger f red possessed by bright galaxies than that by the faint ones. We find that the Butcher-Oemler effect is stronger within the cluster virial radius, where star formation is truncated more rapidly compared with the outskirts. Both bright and faint galaxies exhibit weak dependence of their f red on local galaxy density beyond the cluster virial radius, indicating accelerated evolution driven by galaxy clusters. The gradients between fred and local galaxy densities are larger for the bright galaxies at z ˜ 0.50, but become similar for the bright and faint galaxies at z ˜ 0.30. The cluster environmental influence is effective within ˜ 1.5 virial radii and is stronger in high galaxy density regions, indicating that mechanisms such as harassment and tidal interactions are operating in high galaxy density locations, while ram-pressure is likely the main mechanism in regions of low galaxy density. For environments of similar local galaxy densities and at a fixed cluster-centric radius, galaxies in groups possess larger fred than non-group galaxies, which is usually referred to as 'pre-processing'. We find that the pre-processing is independent of local galaxy density and global cluster environmental impact. Instead, the group environmental influence depends on group richness. We observe a 'group down-sizing' effect such that galaxies in rich groups (of more massive haloes) have their f red evolving with redshift more rapidly than those in poor groups (of less massive haloes). This thesis concludes that the observed properties of galaxy populations result from the combination of their natural characteristics and surrounding environments. Galaxy intrinsic luminosity (mass) determines the efficiency in forming stars, and extrinsic environmental influence accelerates the truncation of star formation.

Li, I.-Hui

447

A Photometric Survey of 93 Young Planetary-Candidate Stars  

NASA Astrophysics Data System (ADS)

Nearly all of the 100 plus extrasolar planets discovered to date have been detected via precise (3--6 m s-1) radial velocity measurements of solar-type stars. The majority of candidate stars surveyed so far were selected to avoid young, active stars because of the associated high levels (10--100 m s-1) of radial velocity jitter in these stars. Persistent starspot activity, lasting for several stellar rotations, can produce periodic radial velocity signals that mimic the presence of orbiting planets. Thus, the extrasolar planetary systems detected so far represent mature systems that have completed most of their planetary orbital evolution. Finding much younger systems and gaining insight into their formation and early evolution requires extending extrasolar planet search surveys to much younger stars, in spite of the radial velocity complications caused by stellar activity. Precise photometry of planetary candidate stars has proven very useful in interpreting the results of radial velocity observations by helping to distinguish between the effects of true reflex motion caused by planetary companions and the radial velocity effects of starspot activity. Several examples of periodic radial velocity variations caused by surface activity have been found. Therefore, we are conducting a photometric survey of 93 young solar-type stars (ages 3 Myr to 3 Gyr) with our automatic photometric telescopes (APTs) at Fairborn Observatory. These stars were selected from a list of targets to be observed by the SIRTF satellite as part of the Legacy Science Project "The Formation and Evolution of Planetary Systems: Placing Our Solar System in Context". SIRTF will study the evolution of planetary systems around these stars by observing their dust disks. Also, the 10-meter Keck telescope will make precise radial velocity observations of these 93 stars to search for young planetary systems. Our APT observations complement the SIRTF and Keck observations by measuring the level of starspot activity in these stars and, in many cases, determining their rotation periods directly. This information will allow the detection of young planetary systems around these stars to be made with greater confidence. We present preliminary results for several stars, including new rotation periods.

Alston, F.; Henry, G. W.; Burks, G. S.

2003-12-01

448

Disk-Resolved Photometric Analysis for Selected Asteroids and Comets  

NASA Astrophysics Data System (ADS)

Disk-resolved photometric analyses primarily using Hapke's scattering theory have been carried out for four objects: asteroid (433) Eros, comet 19P/Borrelly, asteroid (1) Ceres, and comet 9P/Tempel 1. Near Earth Asteroid Rendezvous returned disk-resolved images of Eros at seven wavelengths from 450nm to 1050nm. The single-scattering albedo, w, was found to mimic the spectrum of Eros, with 0.33±0.03 at 550nm. The single-particle phase function parameter, g, is -0.25±0.02, and the roughness parameter, bar ? , is 28o±3o, both of which are wavelength-independent. The V-band geometric albedo of Eros is 0.23, typical for an S-type asteroid. From the resolved images of Borrelly obtained by Deep Space 1 (DS1), the maps of its w, g, and bar ? have been constructed by modeling the reflectance terrain by terrain, with modeled averages of 0.057±0.009, -0.43±0.07, and 22o±5o, respectively. All three parameters show large variations across the surface. The 1-D temperature measurement from DS1 can be well described by the standard thermal model, with small areas adjusted for ice sublimation for observed water production rate. HST images through three filters at 553nm, 335nm, and 223nm, covering more than one rotation of Ceres, were acquired. Its V-band lightcurve agrees with earlier ground-based observations. A strong absorption band centered at about 280nm is noticed. The w at V-band is modeled to be 0.073±0.002. The bar ? is modeled to be 44o±5o. The first surface maps for Ceres at three wavelengths are presented. Deep Impact has returned resolved images of Tempel 1 at seven wavelengths from 350nm to 950nm. The whole-disk spectrum of the nucleus shows a red slope of 12%/1000 angstroms. Photometric modeling yields a w of 0.040 at 650nm, and a surface roughness of about 25o. Only about 50 are observed for the surface of Tempel 1.

Li, J.-Y.; A'Hearn, M. F.; McFadden, L. A.

2005-12-01

449

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

NASA Astrophysics Data System (ADS)

The tables from appendix A (tablea*) list the corrections for projection effects on bulge- disk decomposition, the tables from appendix B (tableb*) list the corrections for the effects of dust on bulge-to-disk decomposition, while the tables from appendix C (tablec*) list the corrections for the effects of dust on single Sersic fits of galaxies containing a disk and a bulge. The corrections in Table A and B are given for the scalelength/effective radius, Sersic index and bulge-to disk ratio of disks and bulges. The corrections in table C are given for the effective radius of composite systems. The corrections are given as a function of inclination, central face-on optical depth in the B band taufB, and wavelength. The parameter space covered by this is as follows: taufB={0.1,0.3,0.5,1.0,2.0,4.0,8.0} wavelength (in Angstrom): 4430,5640,8090,12590,22000. The corrections are provided for photometric fits done with the following functions: i) exponential+Sersic functions for disk and bulge ii) variable index Sersic functions for both the disk and the bulge iii) single Sersic fits The corrections are provided for systems with exponential bulges (i.e. Sersic index fixed to unity) and de Vaucouleurs bulges. The corrections can be used together with the ones given in Pastrav et al. (2013, Cat. J/A+A/553/A80), using Eqs. 10 and 11 from Pastrav et al. (2013, Cat. J/A+A/553/A80). The photometric parameters for which corrections are listed are as follows: R - the exponential scalelength Reff - the effective radius nsers - the Sersic index B/D - bulge-to-disk ratio of the composite system To facilitate access to the information and to allow the corrections to be calculated for any inclination, the corrections are presented in the form of polynomial function fits. For all cases the fitted function is given by Eq. 16 of the paper. (70 data files).

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

2013-08-01

450

Comprehensive Formulation of Titration Curves for Complex AcidBase Systems and Its Analytical Implications  

Microsoft Academic Search

This article provides extensive and exhaustive mathematical description of titration curves related to acid-base systems with mixtures of mono- and polyprotic acids and their salts and bases involved. The related curves are presented in compact forms facilitating further operations made for particular needs. Some derivative properties of the curves, such as buffer capacity and inflection points, are also discussed. The

Agustin G. Asuero; Tadeusz Micha?owski

2011-01-01

451

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

452

Determination of the molecular weight distribution of polyacrylonitrile by turbidimetric titration  

Microsoft Academic Search

candescent lamp served as the light source. A cuvette containing the solution to be titrated was placed in the path of one of the light beams. The optical density of the solution was measured with a Pulfrich refractometer (k = 5330 A). The cuvette (capacity 100 ml) was tetrahedral in shape and was made of plane-parallel glasses and Teflon sheets,

L. S. Gembitskii; G. G. Uglanova

1970-01-01

453

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…

Dungey, Keenan E.; Epstein, Paul

2007-01-01

454

Comparison Optimal Pressure between Automatic Titrating and Predicting Continuous Positive Airway Pressure  

Microsoft Academic Search

Background: Optimal continuous positive airway pressure (CPAP) level reduced excessive daytime sleepiness and improved healthy status compared with subtherapeu- tic CPAP pressure for patients with obstructive sleep apnea syndromes. To date there have been no studies comparing the differences between the auto- matic CPAP titrating pressure levels (ACPAPL) and the predicting CPAP pressure levels (PCPAPL). In this study, we compared

Chung-Chieh Yu; Chung-Ching Hua; Jo-Chi Tseng; Yu-Chi Liu

2006-01-01

455

Differential spatial memory impairment after right temporal lobectomy demonstrated using temporal titration  

Microsoft Academic Search

Summary In this study a temporal titration method to explore the extent to which spatial memory is differentially impaired following right temporal lobectomy was employed. The spatial and non-spatial memory of 19 left and 19 right temporal lobectomy (TL) patients was compared with that of 16 normal controls. The subjects studied an array of 16 toy objects and were subsequently

J. A. Nunn; F. J. X. Graydon; C. E. Polkey; R. G. Morris

1999-01-01