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1

Stellar Populations Surface photometry  

E-print Network

Outline Stellar Populations Surface photometry Luminosity distributions Component separation Surface photometry Luminosity distributions Component separation Photometric parameters Elliptical photometry Luminosity distributions Bulge luminosity laws Luminosity distributions in disks Component

Kruit, Piet van der

2

Surface photometry STRUCTURE OF GALAXIES  

E-print Network

Outline Surface photometry Dynamics Formation STRUCTURE OF GALAXIES 9. Elliptical galaxies Piet van van der Kruit, Kapteyn Astronomical Institute Elliptical galaxies #12;Outline Surface photometry Dynamics Formation Outline Surface photometry Luminosity distributions Shells and ripples Color gradients

Kruit, Piet van der

3

ESP: Extended Surface Photometry  

NASA Astrophysics Data System (ADS)

ESP (Extended Surface Photometry) determines the photometric properties of galaxies and other extended objects. It has applications that detect flatfielding faults, remove cosmic rays, median filter images, determine image statistics and local background values, perform galaxy profiling, fit 2-D Gaussian profiles to galaxies, generate pie slice cross-sections of galaxies, and display profiling results. It is distributed as part of the Starlink software collection (ascl:1110.012)

Privett, Grant; Taylor, Mark; Gray, Norman; Draper, Peter W.; Jenness, Tim

2014-05-01

4

M83. I - Multicolor surface photometry  

Microsoft Academic Search

UBVR surface photometry of the bright southern spiral galaxy NGC 5236 (M83) is presented. Calibrated maps of UBVR and H-alpha surface brightness and colors are compared with models of evolving mixes of stellar populations in order to establish a measurable drift velocity relative to some feature for the young associations supposedly formed in the wake of a spiral density wave.

R. J. Talbot Jr.; E. B. Jensen; R. J. Dufour

1979-01-01

5

CCD surface photometry of galaxies with dynamical data. II. UBR photometry of 39 elliptical galaxies  

Microsoft Academic Search

Intrinsic properties of elliptical galaxies and the mechanisms of their formation and evolution are discussed on the basis of high-precision, multicolor, surface photometry of 39 elliptical galaxies and measurements of rotation curves and velocity dispersion profiles. Using the data collected, a number of correlations between the characteristic parameters of the stellar population of the galaxies have been made to explore

Reynier F. Peletier; Roger L. Davies; L. E. Davis; G. D. Illingworth; Michael Cawson

1990-01-01

6

The Structure of Galaxies I: Surface Photometry Techniques  

NASA Astrophysics Data System (ADS)

This project uses the 2MASS all-sky image database to study the structure of galaxies over a range of luminosities, sizes and morphological types. This first paper in this series will outline the techniques, reliability and data products to our surface photometry program. Our program will analyze all acceptable galaxies (meeting our criteria for isolation from companions and bright stars) from the Revised Shapley-Ames and Uppsala galaxy catalogs. Resulting photometry and surface brightness profiles are released using a transparent scheme of data storage which includes not only all the processed data but knowledge of the processing steps and calibrating parameters.

Schombert, J.; Smith, A. K.

2012-04-01

7

Baltic Astronomy, vol. 8, 535{574, 1999. GALAXY SURFACE PHOTOMETRY  

E-print Network

Baltic Astronomy, vol. 8, 535{574, 1999. GALAXY SURFACE PHOTOMETRY Bo Milvang-Jensen 1;2 and Inger@gemini.edu Received March 3, 2000 Abstract. We describe galaxy surface photometry based on #12;tting ellipses. As examples of applications of surface photometry we discuss the determination of the relative disk

8

NIR surface photometry of a sample of nearby spiral galaxies  

NASA Astrophysics Data System (ADS)

The first results of an observational programme aimed at mapping a sample of face-on spiral galaxies in the NIR are presented. This paper shows the surface photometry of the first ten galaxies in the sample. The data were taken in the broad band J (1.2 mu m) and Ks (2.2 mu m) filters. The sources were selected mainly according to their size and brightness in order to suit the characteristics of the CAIN 2D NIR camera on the 1.5-m Carlos Sánchez Telescope (Tenerife, Spain). The primary scientific goal is to provide a comprehensive and uniform database of the main structural and photometric parameters of the sample members from NIR surface photometry. To this end, elliptical isophotal fitting was performed on each galaxy image to extract information about the size and location of its morphological components and provide the azimuthally averaged radial brightness profile. Analytical functions for each component's brightness distribution were then used to match that profile, and their functional parameters obtained from the global fitting. This first report includes data for NGC 3344, NGC 3686, NGC 3938, NGC 3953, NGC 4254, NGC 4303, NGC 4314, NGC 5248, NGC 6384 and NGC 7479.

Castro-Rodríguez, N.; Garzón, F.

2003-11-01

9

Surface photometry of the shell galaxy NGC 2865  

NASA Astrophysics Data System (ADS)

Independently calibrated charge coupled device surface photometry data were derived from 12 images of the shell galaxy NGC 2865 in the B, V, and R passbands. Short exposures were used to permit accurate sky subtraction. Mean isophotes were derived for each passband over the 3-60 second radial distance range. The isophotes are presented in the form of their best-fit ellipse parameters. The parameters for the best-fit de Vaucouleurs surface brightness law were determined for the mean profile in each passband, and deviations of the actual surface brightness profile from the r to the 1/4 power law are discussed in terms of the galaxy's shell structure. From the best-fit ellipse parameters, the amplitudes of the cosine(4 theta) component of the isophotes could be measured. It was found that they do not show the boxiness often observed in a galaxy which had experienced a recent merger. On the contrary, a peak amplitude of about +1 percent (2 sigma) over the 25-40 second interval suggests only the presence of a weak disk. If the disk is real it indicates NGC 2865 is an S0 galaxy. Both (B-V) and (B-R) color gradients were measured and show the galaxy becomes bluer with increasing radius. This may be explained in terms of a radial metallicity gradient in the sense that the metallicity decreases by about a factor of two per decade increase in distance.

Wing, David Lee

1990-07-01

10

K-band Surface Photometry of the Circinus galaxy  

NASA Astrophysics Data System (ADS)

NIR K-band mosaic and optical B and I-band images of the Circinus galaxy (SA(s)b, 4 Mpc) were taken to study the large-scale structure and the dust opacity. The K-band mosaic image, covering ~ 10.5' x 4.5' , is the first full-coverage K-band image ever taken for this galaxy. 315 image frames were combined to produce the final mosaic with a total integration time of 15 mins/pixel. With very low dust extinction, this astonishing image clearly reveals the large-scale spiral arms at 220" radius, and a nuclear ring or nuclear spiral sturcture at 15" radius. Although not very distinctive, the oval-shaped bar resides at ~ 50" radius. We will present the first K-band surface photometry results for the Circinus galaxy. OKP acknowledges the financial support as scholarships funded by the Australian National University and the Department of Employment, Education, Training and Youth Affairs (DEETYA) of Australia.

Park, O.-K.; Freeman, K. C.

2000-12-01

11

Surface Photometry of Reverberation-Mapped Active Galactic Nuclei  

NASA Astrophysics Data System (ADS)

I present a statistical analysis of the surface photometry obtained for a sample of Hubble Space Telescope (HST) archival images of the host galaxies containing active galactic nuclei (AGN), whose time-delay between continuum and broad emission line variations have been analyzed (i.e., reverberation mapping). For quiescent galaxies, strong correlations exist between central black hole mass and host galaxy structure. If there are similar correlations for AGN between central black hole masses derived from reverberation mapping and the host galaxy structure that I have derived from archival HST images, this would imply some validation of the assumptions underlying reverberation mapping concerning the structure, kinematics, and orientation of the broad line regions in AGN.The correlations for quiescent galaxies bewteen central black hole mass and host galaxy structure imply that there might be a strong causal connection between the formation and evolution of the black hole and the galaxy bulge. A current hypothesis is that bulges, black holes, and quasars formed, grew, or turned on as parts of the same process, in part because the collapse or merger of bulges might provide a rich fuel supply to a central black hole. One way of testing this hypothesis would be to plot AGN as a function of redshift on these correlations. However, two severe obstacles limit the ability to measure black hole masses in AGN using HST to analyze the central stellar and/or gas dynamics: (1) since spatial resolution becomes more limited at larger distances, only two reverberation-mapped AGN are close enough to Earth to render the analysis feasible, and (2) it isdifficult to obtain useful spectra of the stars and/or gas in the presence of the bright nonstellar nucleus. The most useful alternative is to exploit reverberation mapping, which uses the time delay in a given AGN between variations in the continuum emission and broad emission lines.

Bower, Gary A.

2015-01-01

12

Radiative transfer in the surfaces of atmosphereless bodies. III - Interpretation of lunar photometry  

Microsoft Academic Search

Narrowband and UBV photoelectric phase curves of the entire lunar disk and surface photometry of some craters have been interpreted using a newly developed generalized radiative transfer theory for planetary regoliths. The data are well fitted by the theory, yielding information on both macroscopic and microscopic lunar properties. Derived values for the integrated disk geometric albedo are considerably higher than

K. Lumme; W. M. Irvine

1982-01-01

13

Deep near-infrared surface photometry and properties of Local Volume dwarf irregular galaxies  

NASA Astrophysics Data System (ADS)

We present deep H-band surface photometry and analysis of 40 Local Volume galaxies, a sample primarily composed of dwarf irregulars in the Cen A group, obtained using the Infrared Imager and Spectrograph 2 detector at the 3.9-m Anglo-Australian Telescope. We probe to a surface brightness of ˜25 mag arcsec-2, reaching a 40 times lower stellar density than the Two Micron All Sky Survey (2MASS). Employing extremely careful and rigorous cleaning techniques to remove contaminating sources, we perform surface photometry on 33 detected galaxies deriving the observed total magnitude, effective surface brightness and best-fitting Sérsic parameters. We make image quality and surface photometry comparisons to 2MASS and VISTA Hemisphere Survey demonstrating that deep targeted surveys are still the most reliable means of obtaining accurate surface photometry. We investigate the B - H colours with respect to mass for Local Volume galaxies, finding that the colours of dwarf irregulars are significantly varied, eliminating the possibility of using optical-near-infrared colour transformations to facilitate comparison to the more widely available optical data sets. The structure-luminosity relationships are investigated for our `clean' sample of dwarf irregulars. We demonstrate that a significant fraction of the Local Volume dwarf irregular population have underlying structural properties similar to both Local Volume and Virgo cluster dwarf ellipticals. Linear regressions to structure-luminosity relationships for the Local Volume galaxies and Virgo cluster dwarf ellipticals show significant differences in both slope and scatter around the established trend lines, suggesting that environment might regulate the structural scaling relationships of dwarf galaxies in comparison to their more isolated counterparts.

Young, T.; Jerjen, H.; López-Sánchez, Á. R.; Koribalski, B. S.

2014-11-01

14

Planetary surface photometry and imaging: progress and perspectives  

NASA Astrophysics Data System (ADS)

Spacecraft have visited and returned many thousands of images and spectra of all of the planets, many of their moons, several asteroids, and a few comet nuclei during the golden age of planetary exploration. The signal in each pixel of each image or spectral channel is a measurement of the radiance of scattered sunlight into a specific direction. The information on the structure and composition of the surface that is contained in variation of the radiance with scattering geometry and wavelength, including polarization state, has only just begun to be exploited and is the topic of this review. The uppermost surfaces of these bodies are mainly composed of particles that are continuously generated by impacts of micrometeoroids and larger impactors. Models of light scattering by distributions of sizes and irregular shapes of particles and by closely packed particles within a surface are challenging. These are active topics of research where considerable progress has recently been made. We focus on the surfaces of bodies lacking atmospheres. These surfaces are diverse and their morphologies give evidence of their evolution by impacts and resurfacing by a variety of processes including down slope movement and electrostatic transport of particles, gravitational accumulation of debris, volatile outgassing and migration, and magnetospheric interactions. Sampling of scattering geometries and spatial resolution is constrained by spacecraft trajectories. However, the large number of archived images and spectra demand more quantitative interpretation. The scattering geometry dependence of the radiance is underutilized and promises constraints on the compositions and structure of the surface for materials that lack diagnostic wavelength dependence. The general problem is considered in terms of the lunar regolith for which samples have been returned to Earth.

Goguen, Jay D.

2014-10-01

15

Surface properties and photometry of the Uranian satellites  

NASA Technical Reports Server (NTRS)

Voyager photographic images and photopolarimetric experiment observations have been used to obtain the spectral geometric and Bond albedos, phase integrals, color-dependent phase coefficients, and integrated solar phase-curve parameters of the five Uranian satellites Miranda, Ariel, Umbriel, Titania, and Oberon. While the results obtained confirm those of Nelson et al. (1987) and Veverka et al. (1987) that these five largest Uranian satellites constitute a unique class of low-albedo and spectrally flat objects, attention is presently given to important differences among the five moons' surface physical properties.

Buratti, Bonnie; Wong, Felicity; Mosher, Joel

1990-01-01

16

Surface Photometry of Star Clusters in the Dwarf Elliptical Galaxies NGC 185 and NGC 205  

E-print Network

We present the surface photometry of star clusters in the nearby dwarf elliptical galaxies NGC 185 and NGC 205, obtained from deep HST WFPC2 F555W (V) and F814W (I) images. We have obtained surface brightness and color profiles of six star clusters in NGC 185, seven star clusters in NGC 205, and one recently discovered non-stellar object in NGC 205. The surface brightness profiles of ten star clusters are fitted well by the King model, and those of four star clusters are fitted well by the power-law. Three out of ten star clusters fitted well with King model show signs of tidal tails.

Sang Chul Kim; Myung Gyoon Lee; Doug Geisler; Ata Sarajedini; Taft E. Armandroff; Gary S. Da Costa

2001-09-14

17

VizieR Online Data Catalog: WINGS galaxies surface photometry with GASPHOT (D'Onofrio+, 2014)  

NASA Astrophysics Data System (ADS)

Surface photometry parameters are given for the 42275 galaxies analyzed by GASPHOT in the V images of the WINGS survey of local clusters of galaxies, for the 41463 galaxies in the B images and for the 71687 galaxies in the K images. For each galaxy we give the WINGS ID, the equatorial coordinates, the total magnitude (V, B and K respectively), the effective radius along the major axis, the Sersic index, the axial ratio (b/a) and a quality flag. (3 data files).

D'Onofrio, M.; Bindoni, D.; Fasano, G.; Bettoni, D.; Cava, A.; Fritz, J.; Gullieuszik, M.; Kjaergaard, P.; Moretti, A.; Moles, M.; Omizzolo, A.; Poggianti, B. M.; Valentinuzzi, T.; Varela, J.

2014-10-01

18

The structure and dynamics of ringed galaxies. III - Surface photometry and kinematics of the ringed nonbarred spiral NGC 7531  

Microsoft Academic Search

The photometric and kinematic properties of the southern galaxy NGC 7531, a large example of a nonbarred spiral possessing a very bright inner ring, are explored via UVBRI surface photometry and emission-line spectroscopy. The galaxy is a global, two-armed spiral galaxy possessing a bright inner ring with a radius of 2.3 kpc. The ring has an average surface brightness in

R. Buta

1987-01-01

19

THE MID-INFRARED TULLY-FISHER RELATION: SPITZER SURFACE PHOTOMETRY  

SciTech Connect

The availability of photometric imaging of several thousand galaxies with the Spitzer Space Telescope enables a mid-infrared calibration of the correlation between luminosity and rotation in spiral galaxies. The most important advantage of the new calibration in the 3.6 {mu}m band, IRAC Channel 1, is photometric consistency across the entire sky. Additional advantages are minimal obscuration, observations of flux dominated by old stars, and sensitivity to low surface brightness levels due to favorable backgrounds. Roughly 3000 galaxies have been observed through Spitzer cycle 7 and images of these are available from the Spitzer archive. In cycle 8, a program called Cosmic Flows with Spitzer was initiated, which will increase the available sample of spiral galaxies with inclinations greater than 45 Degree-Sign from face-on that are suitable for distance measurements by 1274. This paper describes procedures, based on the photometry package Archangel, that are being employed to analyze both the archival and new data in a uniform way. We give results for 235 galaxies, our calibrator sample for the Tully-Fisher relation. Galaxy magnitudes are determined with uncertainties held below 0.05 mag for normal spiral systems. A subsequent paper will describe the calibration of the [3.6] luminosity-rotation relation.

Sorce, Jenny G.; Courtois, Helene M. [Universite Claude Bernard Lyon 1, Institut de Physique Nucleaire, Lyon (France); Tully, R. Brent, E-mail: j.sorce@ipnl.in2p3.fr [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, HI 96822 (United States)

2012-11-01

20

VizieR Online Data Catalog: Hubble Deep Field surface photometry (Fasano+ 1998)  

NASA Astrophysics Data System (ADS)

The detailed surface photometry of a sample of early-type galaxies in the Hubble Deep Field is presented as part of a long-term project aimed to settle strong observational constraints to the theories modelling the evolution of elliptical galaxies from the early stages. The sample has been extracted, in the V606 band, from the database provided by the ESO-STECF-HDF Group (Couch, 1996, ). The selection criteria involve the total magnitude, the number of pixels detected above the background level and an automatic star/galaxy classifier. Moreover, form visual inspection of the frames, we excluded the galaxies showing unambiguous late-type morphology. The analysis of the luminosity and geometrical profiles, carried out on the 162 candidates obeying our selection criteria, resulted in a list of 99 'bona fide' early-type galaxies, for which accurate total magnitudes and effective radii were computed on the basis of the equivalent luminosity profiles. The comparison with the magnitudes given by Williams et al. (1996, Cat. ) indicates that the automated photometry tends to underestimate the total luminosity of the ellipticals. The luminosity profiles of most of galaxies in our sample follow fairly well the de~Vaucouleurs law ('Normal' profiles). However, a relevant fraction of galaxies, even following the r1/4 law in the main body light distribution, exhibit in the inner region a flattening of the luminosity profile not attributable to the PSF (`Flat' profiles) or, in some cases, a complex (multi-nucleus) structure (`Merger' profiles). A statistically significant correlation is found between the shapes of the luminosity profiles and the ellipticity distribution. In particular, the average ellipticity of galaxies belonging to the `Flat' and `Merger' classes is significantly higher than that of the `Normal' galaxies. Finally, even taken into account the relevant uncertainty of the outer position angle profiles, the amount of isophotal twisting of HDF ellipticals turns out to be significantly larger with respect to that of the local samples. (2 data files).

Fasano, G.; Filippi, M.; Bertola, F.

1997-11-01

21

LROC NAC Photometry as a Tool for Studying Physical and Compositional Properties of the Lunar Surface  

NASA Astrophysics Data System (ADS)

LROC NAC photometry has been used to study the effects of rocket exhaust on lunar soil properties, and here we apply the same photometric methods to place compositional constraints on regions of silicic volcanism and pure anorthosite on the Moon.

Clegg, R. N.; Jolliff, B. L.; Boyd, A. K.; Stopar, J. D.; Sato, H.; Robinson, M. S.; Hapke, B. W.

2014-10-01

22

Photometric calibration of NGS/POSS and ESO/SRC plates using the NOAO PDS measuring engine. II - Surface photometry  

NASA Technical Reports Server (NTRS)

In this paper we present a method to calibrate surface photometry of faint sources measured from direct photographic plates, such as those of the NGS/POSS and ESO/SRC Sky Survey. This calibration procedure does not require scanning sensitometer spots on the plates, but instead uses measurements of the brightness profiles of many faint stars of known brightness to fit a linearized approximation to the characteristic curve. The approximation is valid for only low- to medium-density emulsions, so this technique is appropriate only for relatively faint emission. Comparison between measurements of representative extended sources on the NGS/POSS and CCD images indicates that surface photometry can be obtained from the Sky Survey plates accurate to 0.1-0.3 mag in the range mu(B) between 23 and 27 and mu(R) between 22 and 26 mag/sq arcsec.

Cutri, Roc M.; Low, Frank J.; Guhathakurta, Puragra

1993-01-01

23

B and R surface photometry of faint emission-line galaxies towards nearby cosmic voids  

NASA Astrophysics Data System (ADS)

Detailed B and R surface photometry is performed for 125 faint emission-line galaxies (ELG). They are a subsample of those, which were selected by Popescu et al.(1996) towards four nearby voids. We derive the integral photometric parameters and radial surface brightness (SB) profiles. Our sample consists mostly of low luminosity (=-17.7), small linear size (=6.5 kpc) (H_0 = 75 km s^-1 Mpc^-1) and blue (=0.90) galaxies, which are slightly fainter and bluer than those in Univ. of Michigan ELG-survey (Salzer et al.,1989). We performed the SB profile decomposition into basic bulge and disk components and classified the profiles into 5 types: 19% of studied ELG's are pure disk galaxies; 35% of them show both disk and bulge components; 14% have central light depression and 7% show non-disky (concave) profiles. About 25% of ELG's show almost unresolved (stellar) images and stellar SB profiles. Most of studied ELG's follow the distribution of 'normal' galaxies in CfA Redshift Survey. 16 ELG's were classified as being well isolated (Popescu et al., 1997) and are distributed within nearby voids. These 'void galaxies' are intrinsically ~1.5 mag fainter and about a factor of 1.6 smaller in linear size, than the non-isolated ELG's, but show similar colour characteristics. Our 'void galaxies' are fainter then those, studied in Bootes Void (Cruzen et al., 1997). The isolated ELG's show higher percentage of stellar and non-disky SB profiles, if compared to the non-isolated ELG's.

Vennik, J.; Hopp, U.; Popescu, C.

24

Studies of selected voids. Surface photometry of faint galaxies in the direction of 1600+18 in Hercules void.  

NASA Astrophysics Data System (ADS)

Surface photometry, coordinates, magnitudes m(B), diameters, position angles and some morphological parameters are presented for ca. 1850 faint galaxies in a field of one square degree centered at 1600+18 (1950) (Hercules void). The distribution of the magnitudes of the galaxies in this direction is compared with ''Log Normal'' and ''Gauss'' ones and with similar results from SDDS studies of galaxies. Some candidates for primeval galaxies -- 38 large Low surface brightness galaxies were detected in the direction of the void. Major axes luminosity profiles are analyzed. Comparison between two different methods for automatic selection and classification -- a new package, based on MIDAS INVENTORY and SExtractor packages have been made.

Petrov, Georgi

25

Configurational Equilibrium of Cracks Affected by Surface Stress and  

E-print Network

Configurational Equilibrium of Cracks Affected by Surface Stress and Crack-Tip Point Load Chien HUIC Remote Loading, Surface Stress and Crack-Tip Load 11 22 2 0 - P R P The Bulk-Surface System Free-Body and Surface Stress The Bulk-Surface System Free-Body Of The "Surface" R 2 2 0 2 0 0 0 062999

Wu, Chien H.

26

Multicolor stellar photometry  

NASA Astrophysics Data System (ADS)

The monograph describes all multicolor photometric systems which were in use for stellar photometry before 1990, particularly the UBV, Strömgren and Vilnius systems. The reviews of common properties of photometric systems, energy distribution in stellar spectra, interstellar and atmospheric extinction, photometric classification methods of stars are also given. The book includes calibrations of spectral MK types in absolute magnitudes, bolometric corrections, effective temperatures, surface gravities, masses and radii. Intrinsic color indices of the UBV, Strömgren, Vilnius and infrared systems are tabulated. The volume of the book is 570 pages. A pdf file of the book is available at: http://www.itpa.lt/MulticolorStellarPhotometry/

Straižys, Vytautas

27

Titan: Preliminary results on surface properties and photometry from VIMS observations of the early flybys  

USGS Publications Warehouse

Cassini observations of the surface of Titan offer unprecedented views of its surface through atmospheric windows in the 1-5 ??m region. Images obtained in windows for which the haze opacity is low can be used to derive quantitative photometric parameters such as albedo and albedo distribution, and physical properties such as roughness and particle characteristics. Images from the early Titan flybys, particularly T0, Ta, and T5 have been analyzed to create albedo maps in the 2.01 and 2.73 ??m windows. We find the average normal reflectance at these two wavelengths to be 0.15??0.02 and 0.035??0.003, respectively. Titan's surface is bifurcated into two albedo regimes, particularly at 2.01 ??m. Analysis of these two regimes to understand the physical character of the surface was accomplished with a macroscopic roughness model. We find that the two types of surface have substantially different roughness, with the low-albedo surface exhibiting mean slope angles of ???18??, and the high-albedo terrain having a much more substantial roughness with a mean slope angle of ???34??. A single-scattering phase function approximated by a one-term Henyey-Greenstein equation was also fit to each unit. Titan's surface is back-scattering (g???0.3-0.4), and does not exhibit substantially different backscattering behavior between the two terrains. Our results suggest that two distinct geophysical domains exist on Titan: a bright region cut by deep drainage channels and a relatively smooth surface. The two terrains are covered by a film or a coating of particles perhaps precipitated from the satellite's haze layer and transported by eolian processes. Our results are preliminary: more accurate values for the surface albedo and physical parameters will be derived as more data is gathered by the Cassini spacecraft and as a more complete radiative transfer model is developed from both Cassini orbiter and Huygens Lander measurements. ?? 2006 Elsevier Ltd. All rights reserved.

Buratti, B.J.; Sotin, C.; Brown, R.H.; Hicks, M.D.; Clark, R.N.; Mosher, J.A.; McCord, T.B.; Jaumann, R.; Baines, K.H.; Nicholson, P.D.; Momary, T.; Simonelli, D.P.; Sicardy, B.

2006-01-01

28

Optics on a fractal surface and the photometry of the regoliths  

NASA Astrophysics Data System (ADS)

The light scattered by a rough surface is calculated in a model where the surface is simulated by a mathematical fractal of dimension (D(H) between 2 and 3) and fractal density in the projected area towards the observer rho(H) (rho(H) between 0 and 1). The reflectance on such a surface is calculated in the special case of a 'hemispherical' fractal, in both the geometric optics approximation and a more general diffraction regime. By using a two-parameter phase function (single scattering albedo omega-sub-0 and asymmetry parameter g-sub-0), and including multiple scattering, this four-parameter model is found to reproduce within a good accuracy the phase function of several classes of atmosphereless bodies in the solar system, in good agreement with previous photometric models. The main effect of the diffraction is to reduce the width of the opposition surge by roughly a factor of 2. Another prediction of the model is that the single-scattering contribution due to the fractal part of the surface can be reduced, for nonzero phase angle, to an arbitrarily small amount, for high enough fractal dimension and density. This effect could give a new interpretation of the strong opposition effect observed on some objects, and also of the very low brightness of many solar system bodies.

Drossart, P.

1993-05-01

29

Surface photometry of celestial sources from a space vehicle - Introduction and observational procedures.  

NASA Technical Reports Server (NTRS)

Consideration of the possibility of studying diffuse celestial sources of relatively low surface brightness such as the Milky Way, zodiacal light, and gegenschein from above the earth's atmosphere with equipment flown in artificial satellites. The techniques used for this purpose are reviewed, and some of the difficulties encountered in daytime observations from satellites by the use of a special photometer and polarimeter flown in the orbiting skylab observatory, OSO-6, are cited.

Roach, F. E.; Carroll, B.; Aller, L. H.; Smith, L.

1972-01-01

30

HST Photometry of Triton: Evidence for a Changing Surface in the Outer Solar System  

NASA Astrophysics Data System (ADS)

Triton is one of the few bodies in the solar system with observed cryo-volcanic activity, in the form of plumes (Soderblom et al. 1990). Prompted by evidence from previous observations at ground and space-based telescopes of possible seasonal surface changes on Triton (Young & Stern 1999), we proposed to confirm and characterize these changes using the HST ACS instrument to image Triton at UV, B, V, I and Methane-band wavelengths over as much of its surface as visible from near Earth in 2005. Preliminary analysis indicates a rotation light curve amplitude in excess of that predicted by static models (Hillier et al. 1994 & Hillier 1999) for visual wavelengths, and significant departures from observations taken 12 years earlier in the UV. Surface brightness maps generated from the data show significant departures from the Voyager images obtained in 1989. We will describe in detail these differences which set constraints on activity and surface temperature as well as composition. Such constraints have profound implications for our understanding of Triton's evolution as well as the history of other outer solar system bodies that may undergo similar geophysical processes or have similar composition, such as Pluto (Buratti et al. 2003, Young et al. 2001). References Buratti, B.J., Hillier, J.K., Heinze, A.,Hicks, M.D., Tryka, K.A., Mosher, J.A., Ward, J., Garske, M., Young, J., & Atienza-Rosel, J. Icarus, 162, 171. Hillier, J., Veverka, J., Helfenstein, P., & Lee, P. 1994, Icarus, 109, 296. Hillier, J.K. 1999, Icarus, 139, 202. Soderblom, L.A., Becker, T.L., Kieffer, S.W., Brown, R.H., Hansen, C.J., & Johnson, T.V. 1990, Science, 250, 410. Young, L.A., & Stern, A.S. 1999, AJ, 122, 449. Young, E. F.; Binzel, R. P.; Crane, K. 2001, AJ, 121, 552.

Bauer, James M.; Buratti, B. J.; Li, J. Y.; Hicks, M. D.; Goguen, J. D.; Pilorz, S.; Schmidt, B.; Royle, P.; Herbert, B.; Cobb, B.; Ward, J.; Wright, E.; Acton, C.

2008-09-01

31

Basics of Photometry Photometry: Basic Questions  

E-print Network

Basics of Photometry #12;Photometry: Basic Questions · How do you identify objects in your image type of object you're studying? #12;#12;#12;Topics 1. General Considerations 2. Stellar Photometry 3. Galaxy Photometry #12;I: General Considerations 1. Garbage in, garbage out... 2. Object Detection 3

Masci, Frank

32

Context affects lightness at the level of surfaces.  

PubMed

Visual perception of object attributes such as surface lightness is crucial for successful interaction with the environment. How the visual system assigns lightness to image regions is not yet understood. It has been shown that the context in which a surface is embedded influences its perceived lightness, but whether that influence involves predominantly low-, mid-, or high-level visual mechanisms has not been resolved. To answer this question, we measured whether perceptual attributes of target image regions affected their perceived lightness when they were placed in different contexts. We varied the sharpness of the edge while keeping total target flux fixed. Targets with a sharp edge were consistent with the perceptual interpretation of a surface, and in that case, observers perceived significant brightening or darkening of the target. Targets with blurred edges rather appeared to be spotlights instead of surfaces; for targets with blurred edges, there was much less of a contextual effect on target lightness. The results indicate that the effect of context on the lightness of an image region is not fixed but is strongly affected by image manipulations that modify the perceptual attributes of the target, implying that a mid-level scene interpretation affects lightness perception. PMID:25589299

Maertens, Marianne; Wichmann, Felix A; Shapley, Robert

2015-01-01

33

ARCHANGEL: Galaxy Photometry System  

NASA Astrophysics Data System (ADS)

ARCHANGEL is a Unix-based package for the surface photometry of galaxies. While oriented for large angular size systems (i.e. many pixels), its tools can be applied to any imaging data of any size. The package core contains routines to perform the following critical galaxy photometry functions: sky determinationframe cleaningellipse fittingprofile fittingtotal and isophotal magnitudes The goal of the package is to provide an automated, assembly-line type of reduction system for galaxy photometry of space-based or ground-based imaging data. The procedures outlined in the documentation are flux independent, thus, these routines can be used for non-optical data as well as typical imaging datasets. ARCHANGEL has been tested on several current OS's (RedHat Linux, Ubuntu Linux, Solaris, Mac OS X). A tarball for installation is available at the download page. The main routines are Python and FORTRAN based, therefore, a current installation of Python and a FORTRAN compiler are required. The ARCHANGEL package also contains Python hooks to the PGPLOT package, an XML processor and network tools which automatically link to data archives (i.e. NED, HST, 2MASS, etc) to download images in a non-interactive manner.

Schombert, James

2011-07-01

34

How a Change in Water Phase Affects Surface Temperatures  

NSDL National Science Digital Library

In this problem-based learning (PBL) activity, students take on the role of a student research scientist and explore the role of solar energy in determining climate. Students conduct experiments to observe how a change in water phase affects surface temperatures. Materials required for the investigation include 2 aquariums, dry sand or soil, two heat lamps, and two thermometers.The lesson is supported by teacher notes, answer key, glossary and an appendix with information about using PBL in the classroom. This is the second of three activities in Investigating the Climate System: Energy, a Balancing Act.

2012-08-03

35

Nanocontact electrification: patterned surface charges affecting adhesion, transfer, and printing.  

PubMed

Contact electrification creates an invisible mark, overlooked and often undetected by conventional surface spectroscopic measurements. It impacts our daily lives macroscopically during electrostatic discharge and is equally relevant on the nanoscale in areas such as soft lithography, transfer, and printing. This report describes a new conceptual approach to studying and utilizing contact electrification beyond prior surface force apparatus and point-contact implementations. Instead of a single point contact, our process studies nanocontact electrification that occurs between multiple nanocontacts of different sizes and shapes that can be formed using flexible materials, in particular, surface-functionalized poly(dimethylsiloxane) (PDMS) stamps and other common dielectrics (PMMA, SU-8, PS, PAA, and SiO(2)). Upon the formation of conformal contacts and forced delamination, contacted regions become charged, which is directly observed using Kelvin probe force microscopy revealing images of charge with sub-100-nm lateral resolution. The experiments reveal chemically driven interfacial proton exchange as the dominant charging mechanism for the materials that have been investigated so far. The recorded levels of uncompensated charges approach the theoretical limit that is set by the dielectric breakdown strength of the air gap that forms as the surfaces are delaminated. The macroscopic presence of the charges is recorded using force-distance curve measurements involving a balance and a micromanipulator to control the distance between the delaminated objects. Coulomb attraction between the delaminated surfaces reaches 150 N/m(2). At such a magnitude, the force finds many applications. We demonstrate the utility of printed charges in the fields of (i) nanoxerography and (ii) nanotransfer printing whereby the smallest objects are ?10 nm in diameter and the largest objects are in the millimeter to centimeter range. The printed charges are also shown to affect the electronic properties of contacted surfaces. For example, in the case of a silicon-on-insulator field effect transistors are in contact with PDMS and subsequent delamination leads to threshold voltage shifts that exceed 500 mV. PMID:21526803

Cole, Jesse J; Barry, Chad R; Knuesel, Robert J; Wang, Xinyu; Jacobs, Heiko O

2011-06-01

36

Introduction to astronomical photometry  

Microsoft Academic Search

General definitions and questions of energy distribution for various spectral types are considered along with photometric measurements, effects of bandwidths and interstellar absorption, the two-dimensional photometric representations of stars, multicolor and wideband photometry, intermediate and narrow passband photometry, and photometric parameters and their correlation with basic parameters describing the physical state of stellar atmospheres. Applications of photometry to various stellar

M. Golay

1974-01-01

37

How micropatterns and air pressure affect splashing on surfaces.  

PubMed

We experimentally investigate the splashing mechanism of a millimeter-sized ethanol drop impinging on a structured solid surface, composed of micropillars, through side-view and top-view high-speed imaging. By increasing the impact velocity, we can tune the impact outcome from a gentle deposition to a violent splash, at which tiny droplets are emitted as the liquid sheet spreads laterally. We measure the splashing threshold for different micropatterns and find that the arrangement of the pillars significantly affects the splashing outcome. In particular, directional splashing in the direction in which air flows through the pattern is possible. Our top-view observations of impact dynamics reveal that entrapped air is responsible for the splashing. Indeed, by lowering the pressure of the surrounding air we show that we can suppress the splashing in the explored parameter regime. PMID:20860398

Tsai, Peichun; van der Veen, Roeland C A; van de Raa, Matthias; Lohse, Detlef

2010-10-19

38

Exploration mode affects visuohaptic integration of surface orientation.  

PubMed

We experience the world mostly in a multisensory fashion using a combination of all of our senses. Depending on the modality we can select different exploration strategies for extracting perceptual information. For instance, using touch we can enclose an object in our hand to explore parts of the object in parallel. Alternatively, we can trace the object with a single finger to explore its parts in a serial fashion. In this study we investigated whether the exploration mode (parallel vs. serial) affects the way sensory signals are combined. To this end, participants visually and haptically explored surfaces that varied in roll angle and indicated which side of the surface was perceived as higher. In Experiment 1, the exploration mode was the same for both modalities (i.e., both parallel or both serial). In Experiment 2, we introduced a difference in exploration mode between the two modalities (visual exploration was parallel while haptic exploration was serial or vice versa). The results showed that visual and haptic signals were combined in a statistically optimal fashion only when the exploration modes were the same. In case of an asymmetry in the exploration modes across modalities, integration was suboptimal. This indicates that spatial-temporal discrepancies in the acquisition of information in the two senses (i.e., haptic and visual) can lead to the breakdown of sensory integration. PMID:25413627

Plaisier, Myrthe A; van Dam, Loes C J; Glowania, Catharina; Ernst, Marc O

2014-01-01

39

ARCHANGEL Galaxy Photometry System  

E-print Network

Photometry of galaxies has typically focused on small, faint systems due to their interest for cosmological studies. Large angular size galaxies, on the other hand, offer a more detailed view into the properties of galaxies, but bring a series of computational and technical difficulties that inhibit the general astronomer from extracting all the information found in a detailed galaxy image. To this end, a new galaxy photometry system has been developed (mostly building on tools and techniques that have existed in the community for decades) that combines ease of usage with a mixture of pre-built scripts. The audience for this system is a new user (graduate student or non-optical astronomer) with a fast, built-in learning curve to offer any astronomer, with imaging data, a suite of tools to quickly extract meaningful parameters from decent data. The tools are available either by a client/server web site or by tarball for personal installation. The tools also provide simple scripts to interface with various on-line datasets (e.g. 2MASS, Sloan, DSS) for data mining capability of imaged data. As a proof of concept, we preform a re-analysis of the 2MASS Large Galaxy Atlas to demonstrate the differences in an automated pipeline, with its emphasis on speed, versus this package with an emphasis on accuracy. This comparison finds the structural parameters extracted from the 2MASS pipeline is seriously flawed with scale lengths that are too small by 50% and central surface brightness that are, on average, 1 to 0.5 mags too bright. A cautionary tale on how to reduce information-rich data such as surface brightness profiles. This document and software can be found at http://abyss.uoregon.edu/~js/archangel.

J. Schombert

2007-03-26

40

Plant surface wax affects parasitoid's response to host footprints  

NASA Astrophysics Data System (ADS)

The plant surface is the substrate upon which herbivorous insects and natural enemies meet and thus represents the stage for interactions between the three trophic levels. Plant surfaces are covered by an epicuticular wax layer which is highly variable depending on species, cultivar or plant part. Differences in wax chemistry may modulate ecological interactions. We explored whether caterpillars of Spodoptera frugiperda, when walking over a plant surface, leave a chemical trail (kairomones) that can be detected by the parasitoid Cotesia marginiventris. Chemistry and micromorphology of cuticular waxes of two barley eceriferum wax mutants ( cer-za.126, cer-yp.949) and wild-type cv. Bonus (wt) were assessed. The plants were then used to investigate potential surface effects on the detectability of caterpillar kairomones. Here we provide evidence that C. marginiventris responds to chemical footprints of its host. Parasitoids were able to detect the kairomone on wild-type plants and on both cer mutants but the response to cer-yp.949 (reduced wax, high aldehyde fraction) was less pronounced. Experiments with caterpillar-treated wt and mutant leaves offered simultaneously, confirmed this observation: no difference in wasp response was found when wt was tested against cer-za.126 (reduced wax, wt-like chemical composition) but wt was significantly more attractive than cer-yp.949. This demonstrates for the first time that the wax layer can modulate the detectability of host kairomones.

Rostás, Michael; Ruf, Daniel; Zabka, Vanessa; Hildebrandt, Ulrich

2008-10-01

41

Free-surface stability criterion as affected by velocity distribution  

USGS Publications Warehouse

This paper examines how the velocity distribution of flow in open channels affects the kinematic and dynamic wave velocities, from which the various forms of the Vedernikov number V can be formulated. When V >1, disturbances created in open-channel flow will amplify in the form of roll waves; when V <1, some (though not all) disturbances will attenuate. A study of the Vedernikov stability criterion reveals that it can be readily deduced within the framework of the kinematic and dynamic wave theories by comparing the kinematic wave velocity to the corresponding dynamic wave velocity. -from Author

Cheng-Lung, Chen

1995-01-01

42

Surface Water Quality as Affected by Sugarcane Residue Management Techniques  

Microsoft Academic Search

This study evaluated the impacts of three sugarcane residue management techniques, namely postharvest burning of residue (BR),\\u000a shredding of residue (SR), and full postharvest retention of residue (RR), on the water quality of surface runoff from February\\u000a 2006 to September 2007 in Iberia, LA. Total runoff volumes recorded were 58,418, 57,923, and 46,578 L for the BR, SR, and\\u000a RR treatments,

Theophilus K. Udeigwe; Jim J. Wang; Howard P. Viator; Lewis Gaston

2010-01-01

43

Coefficients of Friction for Apple on Various Surfaces As Affected by Velocity by  

Microsoft Academic Search

The static and dynamic coefficients of friction were determined for two apple cultivars against four different surfaces (masonite, rubber, paper, plastic) at surface moving velocities of 0.42 to 16.67 mm\\/s. Over this range of velocities, friction coefficients increased by 30 to 100%. Sliding velocity affected dynamic coefficient more than preloading velocity affected the static coefficient. Differences between the tested surfaces

C. Puchalski; G. H. Brusewitz

44

H I 21 centimeter observations and I-band CCD surface photometry of spiral galaxies behind the Virgo Cluster and toward its antipode  

NASA Technical Reports Server (NTRS)

Sample selection, radio and optical data acquisition and reduction, and observation results are presented for spiral galaxies behind the Virgo Cluster and toward its antipode. I-band CCD photometry was obtained for all the bright galaxies and part of the sample of faint galaxies in the two local volumes was studied. The statistical properties of the galaxy samples are discussed.

Lu, N. Y.; Hoffman, G. L.; Groff, T.; Roos, T.; Lamphier, C.

1993-01-01

45

THE SL2S GALAXY-SCALE LENS SAMPLE. III. LENS MODELS, SURFACE PHOTOMETRY, AND STELLAR MASSES FOR THE FINAL SAMPLE  

SciTech Connect

We present Hubble Space Telescope (HST) imaging data and Canada-France-Hawaii Telescope (CFHT) near-infrared ground-based images for the final sample of 56 candidate galaxy-scale lenses uncovered in the CFHT Legacy Survey as part of the Strong Lensing in the Legacy Survey project. The new images are used to perform lens modeling, measure surface photometry, and estimate stellar masses of the deflector early-type galaxies (ETGs). Lens modeling is performed on the HST images (or CFHT when HST is not available) by fitting the spatially extended light distribution of the lensed features assuming a singular isothermal ellipsoid mass profile and by reconstructing the intrinsic source light distribution on a pixelized grid. Based on the analysis of systematic uncertainties and comparison with inference based on different methods, we estimate that our Einstein radii are accurate to ?3%. HST imaging provides a much higher success rate in confirming gravitational lenses and measuring their Einstein radii than CFHT imaging does. Lens modeling with ground-based images, however, when successful, yields Einstein radius measurements that are competitive with space-based images. Information from the lens models is used together with spectroscopic information from companion Paper IV to classify the systems, resulting in a final sample of 39 confirmed (grade A) lenses and 17 promising candidates (grade B,C). This represents an increase of half an order of magnitude in sample size with respect to the sample of confirmed lenses studied in Papers I and II. The Einstein radii of the confirmed lenses in our sample span the range 5-15 kpc and are typically larger than those of other surveys, probing the mass in regions where the dark matter contribution is more important. Stellar masses are in the range 10{sup 11}-10{sup 12} M{sub ?}, covering the range of massive ETGs. The redshifts of the main deflector span a range 0.3 ? z{sub d} ? 0.8, which nicely complements low-redshift samples like the Sloan Lens ACS survey and thus provides an excellent sample for the study of the cosmic evolution of the mass distribution of ETGs over the second half of the history of the universe.

Sonnenfeld, Alessandro; Suyu, Sherry H.; Treu, Tommaso [Physics Department, University of California, Santa Barbara, CA 93106 (United States); Gavazzi, Raphaël [Institut d'Astrophysique de Paris, UMR7095 CNRS-Université Pierre et Marie Curie, 98bis bd Arago, F-75014 Paris (France); Marshall, Philip J., E-mail: sonnen@physics.ucsb.edu [Department of Physics, University of Oxford, Keble Road, Oxford, OX1 3RH (United Kingdom)

2013-11-10

46

Conditions affecting the release of phosphorus from surface lake sediments.  

PubMed

Laboratory studies were conducted to determine the effect of pH and redox conditions, as well as the effect of Fe, Mn, Ca, Al, and organic matter, on the release of ortho-phosphates in lake sediments taken from Lakes Koronia and Volvi (Northern Greece). Results were evaluated in combination with experiments to determine P fractionation in the sediment. The study revealed the major effect of redox potential and pH on the release of P from lake sediments. Both lakes showed increased release rates under reductive conditions and high pH values. The fractionation experiments revealed increased mobility of the reductive P fraction as well as of the NaOH-P fraction, indicating participation of both fractions in the overall release of sediment-bound P, depending on the prevailing environmental conditions. The results were assessed in combination with the release patterns of Fe, Mn, Ca, Al, and organic matter, enabling the identification of more specific processes of P release for each lake. The basic release patterns included the redox induced reductive dissolution of P-bearing metal oxides and the competitive exchange of phosphate anions with OH- at high pH values. The formation of an oxidized surface microlayer under oxic conditions acted as a protective film, preventing further P release from the sediments of Lake Volvi, while sediments from Lake Koronia exhibited a continuous and increased tendency to release P under various physicochemical conditions, acting as a constant source of internal P loading. PMID:16738404

Christophoridis, Christophoros; Fytianos, Konstantinos

2006-01-01

47

Galileo photometry of Asteroid 951 Gaspra  

Microsoft Academic Search

The mean photometric properties of Gaspra's surface are derived in terms of Hapke's photometric model by combining earth-based telescopic photometry with Galileo's whole-disk and disk-resolved data. The results are used to estimate fundamental properties, such as the geometric albedo, and to compare surface materials on Gaspra with materials on other planetary surfaces. The photometric parameters and a new shape model

P. Helfenstein; J. Veverka; P. C. Thomas; D. P. Simonelli; P. Lee; K. Klaasen; T. V. Johnson; H. Breneman; J. W. Head; S. Murchie

1994-01-01

48

APT: Aperture Photometry Tool  

NASA Astrophysics Data System (ADS)

Aperture Photometry Tool (APT) is software for astronomers and students interested in manually exploring the photometric qualities of astronomical images. It has a graphical user interface (GUI) which allows the image data associated with aperture photometry calculations for point and extended sources to be visualized and, therefore, more effectively analyzed. Mouse-clicking on a source in the displayed image draws a circular or elliptical aperture and sky annulus around the source and computes the source intensity and its uncertainty, along with several commonly used measures of the local sky background and its variability. The results are displayed and can be optionally saved to an aperture-photometry-table file and plotted on graphs in various ways using functions available in the software. APT is geared toward processing sources in a small number of images and is not suitable for bulk processing a large number of images, unlike other aperture photometry packages (e.g., SExtractor). However, APT does have a convenient source-list tool that enables calculations for a large number of detections in a given image. The source-list tool can be run either in automatic mode to generate an aperture photometry table quickly or in manual mode to permit inspection and adjustment of the calculation for each individual detection. APT displays a variety of useful graphs, including image histogram, and aperture slices, source scatter plot, sky scatter plot, sky histogram, radial profile, curve of growth, and aperture-photometry-table scatter plots and histograms. APT has functions for customizing calculations, including outlier rejection, pixel “picking” and “zapping,” and a selection of source and sky models. The radial-profile-interpolation source model, accessed via the radial-profile-plot panel, allows recovery of source intensity from pixels with missing data and can be especially beneficial in crowded fields.

Laher, Russ

2012-08-01

49

New insights to the photometric structure of Blue Compact Dwarf galaxies from deep Near-Infrared studies. I. Observations, surface photometry and decomposition of surface brightness profiles  

NASA Astrophysics Data System (ADS)

We have analyzed deep Near Infrared (NIR) broad band images for a sample of Blue Compact Dwarf Galaxies (BCDs), observed with the ESO NTT and Calar Alto 3.6 m telescopes. The data presented here allows for the detection and quantitative study of the extended stellar low-surface brightness (LSB) host galaxy in all sample BCDs. NIR surface brightness profiles (SBPs) of the LSB host galaxies agree at large galactocentric radii with those from optical studies, showing also an exponential intensity decrease and compatible scale lengths. At small to intermediate radii (within 1-3 exponential scale lengths), however, the NIR data reveals for more than one half of our sample BCDs evidence for a significant flattening of the exponential profile of the LSB component. Such profiles (type V SBPs, Binggeli & Cameron \\cite{binggeli91}) have rarely been detected in the LSB component of BCDs at optical wavelengths, where the relative flux contribution of the starburst, being stronger than in the NIR, can readily hide a possible central intensity depression in the underlying LSB host. The structural properties, frequency and physical origin of type V LSB profiles in BCDs and dwarf galaxies in general have not yet been subject to systematic studies. Nevertheless, the occurrence of such profiles in an appreciable fraction of BCDs would impose important new observational constraints to the radial mass distribution of the stellar LSB component, as well as to the photometric fading of these systems after the termination of star-forming activities. We test the suitability of two empirical fitting functions, a modified exponential distribution (Papaderos et al. \\cite{papaderos96a}) and the Sérsic law, for the systematization of the structural properties of BCD host galaxies which show a type V intensity distribution. Either function has been found to satisfactorily fit a type V distribution. However, it is argued that the practical applicability of Sérsic fits to the LSB emission of BCDs is limited by the extreme sensitivity of the achieved solutions to, e.g., small uncertainties in the sky subtraction and SBP derivation. We find that most of the sample BCDs show in their stellar LSB host galaxy optical-NIR colors indicative of an evolved stellar population with subsolar metallicity. Unsharp-masked NIR maps reveal numerous morphological details and indicate in some cases, in combination with optical data, appreciable non-uniform dust absorption on a spatial scale as large as ~ 1 kpc. European Southern Observatory, program ID 65.N-0318(A). German-Spanish Astronomical Center, Calar Alto, operated by the Max-Planck-Institute for Astronomy, Heidelberg, jointly with the Spanish National Commission for Astronomy.

Noeske, K. G.; Papaderos, P.; Cairós, L. M.; Fricke, K. J.

2003-11-01

50

Aperture Photometry Tool  

NASA Astrophysics Data System (ADS)

Aperture Photometry Tool (APT) is software for astronomers and students interested in manually exploring the photometric qualities of astronomical images. It is a graphical user interface (GUI) designed to allow the image data associated with aperture photometry calculations for point and extended sources to be visualized and, therefore, more effectively analyzed. The finely tuned layout of the GUI, along with judicious use of color-coding and alerting, is intended to give maximal user utility and convenience. Simply mouse-clicking on a source in the displayed image will instantly draw a circular or elliptical aperture and sky annulus around the source and will compute the source intensity and its uncertainty, along with several commonly used measures of the local sky background and its variability. The results are displayed and can be optionally saved to an aperture-photometry-table file and plotted on graphs in various ways using functions available in the software. APT is geared toward processing sources in a small number of images and is not suitable for bulk processing a large number of images, unlike other aperture photometry packages (e.g., SExtractor). However, APT does have a convenient source-list tool that enables calculations for a large number of detections in a given image. The source-list tool can be run either in automatic mode to generate an aperture photometry table quickly or in manual mode to permit inspection and adjustment of the calculation for each individual detection. APT displays a variety of useful graphs with just the push of a button, including image histogram, x and y aperture slices, source scatter plot, sky scatter plot, sky histogram, radial profile, curve of growth, and aperture-photometry-table scatter plots and histograms. APT has many functions for customizing the calculations, including outlier rejection, pixel ""picking"" and ""zapping,"" and a selection of source and sky models. The radial-profile-interpolation source model, which is accessed via the radial-profile-plot panel, allows recovery of source intensity from pixels with missing data and can be especially beneficial in crowded fields.

Laher, Russ R.; Gorjian, Varoujan; Rebull, Luisa M.; Masci, Frank J.; Fowler, John W.; Helou, George; Kulkarni, Shrinivas R.; Law, Nicholas M.

2012-07-01

51

Friction, Wear, and Surface Damage of Metals as Affected by Solid Surface Films  

NASA Technical Reports Server (NTRS)

As predicted by friction theory, experiments showed that friction and surface damage of metals can be reduced by solid surface films. The ability of materials to form surface films that prevent welding was a very important factor in wear of dry and boundary lubricated surfaces. Films of graphitic carbon on cast irons, nio on nickel alloys, and feo and fe sub 3 o sub 4 on ferrous materials were found to be beneficial. Abrasive films such as fe sub 2 o sub 3 or moo sub 3 were definitely detrimental. It appears that the importance of oxide films to friction and wear processes has not been fully appreciated.

Bisson, Edmond E; Johnson, Robert L; Swikert, Max A; Godfrey, Douglas

1956-01-01

52

UBVI CCD Photometry of the Open Cluster NGC 559  

NASA Astrophysics Data System (ADS)

We have conducted UBVI CCD photometry of an intermediate-age open cluster NGC 559 to investigate the effect of dynamical evolution on the stellar distributions in NGC 559. Our photometry allows better estimates of distance and age of the cluster owing to much deeper photometry (V <= 21) than previous ones. It is found that the luminosity function and mass function as well as the spatial stellar distributions are affected by the dynamical evolution. Mass segregation leads to the central concentration of the high mass stars, which results in the flattened mass function inside the half mass radius.

Ann, Hong Bae; Lee, Sang Hyun

2002-03-01

53

Unfiltered photometry of asteroids.  

NASA Astrophysics Data System (ADS)

Unfiltered Photometry of Asteroids Most asteroid search and astrometric programs use no photometric filters. Yet all these programs report magnitudes. What does this mean? What color should be reported? How accurate is it? This talk will present the results of recent calibrations against standards (Landolt) at the Grasslands Observatory (using a site CCD and a 62 cm reflector). Comparisons between filtered and unfiltered images using both the USNO-SA2.0 and GSC 1.1 catalogs will be presented.

McGaha, J.

1999-04-01

54

Introduction to Astronomical Photometry  

NASA Astrophysics Data System (ADS)

This textbook for graduate students in observational astronomy, describes the methods used to measure the radiation (mostly in the optical domain) from stars. It starts with an overview, followed by definitions of the main terms encountered in the subject. This is followed by a description of the fundamental physical theory of the measurement of radiative flux. Wide ranging problems in astronomical photometry are then approached. The central chapters deal with photometer design, data handling techniques, and the generation of light curves. Many applications of photometry are then described. Users of this textbook will be able to develop an interest in the practicalities of obtaining data of good quality from photometry. The book will appeal to amateur and professional astronomers engaged in variable star observations and the measurement of stellar luminosity. It is intended to encourage interest in the practicalities of observational astronomy and an understanding of stellar astrophysics from a data-based perspective. It fills a gap between a popular approach and a research monograph.

Budding, Edwin

1993-09-01

55

The 2060 Chiron: CCD photometry  

NASA Technical Reports Server (NTRS)

R-band CCD photometry of 2060 was carried out on nine nights in Nov. and Dec. 1986. The rotation period is 5.9181 + or - 0.0003 hr and the peak to peak lightcurve amplitude is 0.088 + or - 0.0003 mag. Photometric parameters are H sub R = 6.24 + or - 0.02 mag and G sub R = + or - 0.15, though formal errors may not be realistic. The lightcurve has two pairs of extrema, but its asymmetry, as evidenced by the presence of significant odd Fourier harmonics, suggests macroscopic surface irregularities and/or the presence of some large scale albedo variegation. The observational rms residual is + or - 0.015 mag. On time scales from minutes to days there is no evidence for nonperiodic (cometary) brightness changes at the level of a few millimagnitudes.

Bus, Schelte J.; Bowell, Edward; Harris, Alan W.

1987-01-01

56

THE IMPACT OF CONTAMINATED RR LYRAE/GLOBULAR CLUSTER PHOTOMETRY ON THE DISTANCE SCALE  

SciTech Connect

RR Lyrae variables and the stellar constituents of globular clusters are employed to establish the cosmic distance scale and age of the universe. However, photometry for RR Lyrae variables in the globular clusters M3, M15, M54, M92, NGC 2419, and NGC 6441 exhibit a dependence on the clustercentric distance. For example, variables and stars positioned near the crowded high-surface brightness cores of the clusters may suffer from photometric contamination, which invariably affects a suite of inferred parameters (e.g., distance, color excess, absolute magnitude, etc.). The impetus for this study is to mitigate the propagation of systematic uncertainties by increasing awareness of the pernicious impact of contaminated and radial-dependent photometry.

Majaess, D.; Turner, D.; Lane, D. [Department of Astronomy and Physics, Saint Mary's University, Halifax, NS B3H 3C3 (Canada); Gieren, W., E-mail: dmajaess@ap.smu.ca [Departamento de Astronomia, Universidad de Concepcion, Casilla 160-C, CL Concepcion (Chile)

2012-06-10

57

Towards understanding how surface life can affect interior geological processes: a non-equilibrium thermodynamics approach  

NASA Astrophysics Data System (ADS)

Life has significantly altered the Earth's atmosphere, oceans and crust. To what extent has it also affected interior geological processes? To address this question, three models of geological processes are formulated: mantle convection, continental crust uplift and erosion and oceanic crust recycling. These processes are characterised as non-equilibrium thermodynamic systems. Their states of disequilibrium are maintained by the power generated from the dissipation of energy from the interior of the Earth. Altering the thickness of continental crust via weathering and erosion affects the upper mantle temperature which leads to changes in rates of oceanic crust recycling and consequently rates of outgassing of carbon dioxide into the atmosphere. Estimates for the power generated by various elements in the Earth system are shown. This includes, inter alia, surface life generation of 264 TW of power, much greater than those of geological processes such as mantle convection at 12 TW. This high power results from life's ability to harvest energy directly from the sun. Life need only utilise a small fraction of the generated free chemical energy for geochemical transformations at the surface, such as affecting rates of weathering and erosion of continental rocks, in order to affect interior, geological processes. Consequently when assessing the effects of life on Earth, and potentially any planet with a significant biosphere, dynamical models may be required that better capture the coupled nature of biologically-mediated surface and interior processes.

Dyke, J. G.; Gans, F.; Kleidon, A.

2011-06-01

58

Lunar Mare Photometry from SMART-1/AMIE Data  

NASA Astrophysics Data System (ADS)

The SMART-1 spacecraft pioneered European lunar exploration with its orbiting mission in 2004-2006. Among its instruments was the optical/near-infrared camera AMIE which mapped the lunar surface with a resolution between 40 to 200 metres per pixel. We have taken a sample of over eight hundred AMIE frames, representing most of the mare regions of the near side. We extracted multi-angular photometry from the images by sampling the brightness of the surface and estimating the local observational geometry (the directions to the camera and the Sun compared to the surface normal). We assume that the photometric properties of mare surfaces are similar in all the regions studied and consider the entire data set as representing "average" mare properties. Mare surfaces were chosen because they are smooth, making the estimation of the observational geometry simple, and also because they are dark, justifying the use of the Lommel-Seeliger scattering law. Using a numerical ray-tracing code with a simulated regolith medium we compute the effect of mutual shadowing of surface particles. This simulation considers the full observational geometry and includes azimuthal shadowings effects. The contribution of shadowing can then be removed from the data, resulting in a phase function for the lunar mare surfaces. In all cases, the reduced phase function shows a significant opposition effect, indicating that the lunar opposition effect is not explainable through shadowing effects only. Physical properties of the surface such as porosity and surface roughness affect the shadowing function. By varying these properties in the ray-tracing simulation, some information of the corresponding properties of the lunar surface may be gained. Research supported, in part, by the Academy of Finland (contract 127461) and by the NASA Lunar Advanced Science and Exploration Research Program (contract NNX11AB25G).

Wilkman, Olli; Muinonen, K.; Parviainen, H.; Näränen, J.; Videen, G.; Josset, J.; Beauvivre, S.; SMART-1 AMIE Team

2012-10-01

59

Introduction Observations PSF fitting Photometry Results Defocused PSF-fitting Photometry  

E-print Network

Introduction Observations PSF fitting Photometry Results Defocused PSF-fitting Photometry Ro Parviainen Defocused PSF-fitting Photometry #12;Introduction Observations PSF fitting Photometry Results 1 Introduction The light curve Defocused PSF 2 Observations Observations 3 PSF fitting Photometry PSF model 1 PSF

Pinfield, David J.

60

One Percent Strömvil Photometry in M 67  

NASA Astrophysics Data System (ADS)

The Vatican Advanced Technology Telescope on Mt. Graham is being used in a program of CCD photometry of open and globular clusters. We are using the Ströomvil System (Straižys et al. 1996), a combination of the Strömgren and Vilnius Systems. This system allows stars to be classified as to temperature, surface gravity, metallicity and reddening from the photometric measures alone. However, to make accurate estimates of the stellar parameters the photometry should be accurate to 1 or 1.5 percent. In our initial runs on the VATT we did not achieve this accuracy. The problem turned out to be scattered light in the telescope and this has now been reduced so we can do accurate photometry. Boyle has written a routine in IRAF which allows us to correct the flats for any differences. We take rotated frames and also frames which are offset in position by one third of a frame, east-west and north-south. Measures of the offset stars give us the corrections that need to be made to the flat. Robert Janusz has written a program, the CommandLog, which allows us to paste IRAF commands in the correct order to reduce measures made on a given observing run. There is an automatic version where one can test various parameters and get a set of solutions. Now we have a set of Strömvil frames in the open cluster, M 67 and we compare our color-magnitude diagram with those of BATC (Fan et al. 1996) and Vilnius (Boyle et al. 1998). A preliminary report of the M 67 photometry will be found in Laugalys et al. (2004). Here we report on a selected set of stars in the M 67 frames, those with errors 1 percent or less.

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

2005-05-01

61

Modeling of Grain Structure and Heat-Affected Zone in Laser Surface Melting Process  

NASA Astrophysics Data System (ADS)

A combination of phase-field and cellular automata methods is used to study the effect of initial grain size and laser power density on heat-affected zone (HAZ) formation during laser surface melting. Also, an analytical model is developed to estimate the depth of HAZ as a function of initial grain size and process parameters. Both analytical and numerical results indicate that the size of HAZ, as measured with respect to the changes in the grain structure, is inversely proportional to the initial grain size. They also show how increasing the laser power leads to an increase in the extent of HAZ. The proposed models thus provide a basis for the prediction and control of HAZ in laser surface melting.

Jabbareh, Mohammad Amin; Assadi, Hamid

2013-08-01

62

Interacting components of the top-of-atmosphere energy balance affect changes in regional surface temperature  

NASA Astrophysics Data System (ADS)

The role of interactions between components of the top-of-atmosphere (TOA) energy balance in determining regional surface temperature changes, such as polar amplification, is examined in diffusive energy balance model (EBM) simulations. These interactions have implications for the interpretation of local feedback analyses when they are applied to regional surface temperature changes. Local feedback analysis succeeds at accounting for the EBM-simulated temperature change given the changes in the radiative forcing, atmospheric energy transport, and radiative feedbacks. However, the inferences about the effect of individual components of the TOA energy balance on regional temperature changes do not account for EBM simulations in which individual components are prescribed or "locked." As changes in one component of the TOA energy balance affect others, unambiguous attribution statements relating changes in regional temperature or its intermodel spread to individual terms in the TOA energy balance cannot be made.

Merlis, Timothy M.

2014-10-01

63

DIRECT COMPARISON OF KINETIC AND LOCAL EQUILIBRIUM FORMULATIONS FOR SOLUTE TRANSPORT AFFECTED BY SURFACE REACTIONS.  

USGS Publications Warehouse

Modeling transport of reacting solutes in porous media often requires a choice between models based on the local equilibrium assumption (LEA) and models involving reaction kinetics. Direct comparison of the mathematical formulations for these two types of transport models can aid in this choice. For cases of transport affected by surface reaction, such a comparison is made possible by a new derivation procedure. This procedure yields a kinetics-based formulation that is the sum of the LEA formulation and one or more kinetically influenced terms. The dimensionless form of the new kinetics-based formulation facilitates identification of critical parameter groupings which control the approach to transport behavior consistent with LEA model predictions. Results of numerical experiments demonstrate that criteria for LEA applicability can be expressed conveniently in terms of these parameter groupings. The derivation procedure is demonstrated for examples of surface reactions including first-order reversible sorption, Langmuir-type kinetics and binary, homovalent ion exchange.

Bahr, Jean M.; Rubin, Jacob

1987-01-01

64

How will surface treatments affect the translucency of porcelain laminate veneers?  

PubMed Central

PURPOSE The purpose of this study was to evaluate whether surface treatments affect the translucency of laminate veneers with different shades and thicknesses. MATERIALS AND METHODS A total of 224 disc-shaped ceramic veneers were prepared from A1, A3, HT (High Translucent) and HO (High Opaque) shades of IPS e.max Press (Ivoclar Vivadent) with 0.5 mm and 1.0 mm thicknesses. The ceramics were divided into four groups for surface treatments. Group C: no surface treatments; Group HF: etched with hydrofluoric acid; Group SB: sandblasted with 50-µm Al2O3; and Group L; irradiated with an Er;YAG laser. A translucent shade of resin cement (Rely X Veneer, 3M ESPE) was chosen for cementation. The color values of the veneers were measured with a colorimeter and translucency parameter (TP) values were calculated. A three-way ANOVA with interactions for TP values was performed and Bonferroni tests were used when appropriate (?=0.05). RESULTS There were significant interactions between the surface treatments, ceramic shades and thicknesses (P=.001). For the 0.5-mm-thick specimens there were significant differences after the SB and L treatments. There was no significant difference between the HF and C treatments for any shades or thicknesses (P>.05). For the 1-mm-thick ceramics, there was only a significant difference between the L and C treatments for the HT shade ceramics (P=.01). There were also significant differences between the SB and C treatments except not for the HO shades (P=.768). CONCLUSION The SB and L treatments caused laminate veneers to become more opaque; however, HF treatment did not affect the TP values. When the laminate veneers were thinner, both the shade of the ceramic and the SB and laser treatments had a greater effect on the TP values. PMID:24605200

Turgut, Sedanur; Ayaz, Elif Aydogan; Korkmaz, Fatih Mehmet; Ulusoy, K?vanç Utku; Bagis, Yildirim Hakan

2014-01-01

65

Comparison of aerosol optical depth inferred from surface measurements with that determined by Sun photometry for cloud-free conditions at a continental U.S. site  

Microsoft Academic Search

Evaluation of the forcing of climate by aerosol scattering of shortwave radiation in cloud-free conditions (direct aerosol forcing) requires knowledge of aerosol optical properties on relevant spatial and temporal scales. It is convenient to measure these properties at the surface. However, before these measurements can be used to quantitatively estimate direct climate forcing, it is necessary to determine the extent

M. H. Bergin; S. E. Schwartz; R. N. Halthore; J. A. Ogren; D. L. Hlavka

2000-01-01

66

Osteoclasts but not osteoblasts are affected by a calcified surface treated with zoledronic acid in vitro  

SciTech Connect

Bisphosphonates are potent inhibitors of osteoclast-mediated bone resorption. Recent interest has centered on the effects of bisphosphonates on osteoblasts. Chronic dosing of osteoblasts with solubilized bisphosphonates has been reported to enhance osteogenesis and mineralization in vitro. However, this methodology poorly reflects the in vivo situation, where free bisphosphonate becomes rapidly bound to mineralized bone surfaces. To establish a more clinically relevant cell culture model, we cultured bone cells on calcium phosphate coated quartz discs pre-treated with the potent nitrogen-containing bisphosphonate, zoledronic acid (ZA). Binding studies utilizing [{sup 14}C]-labeled ZA confirmed that the bisphosphonate bound in a concentration-dependent manner over the 1-50 {mu}M dose range. When grown on ZA-treated discs, the viability of bone-marrow derived osteoclasts was greatly reduced, while the viability and mineralization of the osteoblastic MC3T3-E1 cell line were largely unaffected. This suggests that only bone resorbing cells are affected by bound bisphosphonate. However, this system does not account for transient exposure to unbound bisphosphonate in the hours following a clinical dosing. To model this event, we transiently treated osteoblasts with ZA in the absence of a calcified surface. Osteoblasts proved highly resistant to all transitory treatment regimes, even when utilizing ZA concentrations that prevented mineralization and/or induced cell death when dosed chronically. This study represents a pharmacologically more relevant approach to modeling bisphosphonate treatment on cultured bone cells and implies that bisphosphonate therapies may not directly affect osteoblasts at bone surfaces.

Schindeler, Aaron [Department of Orthopaedic Research and Biotechnology, Children's Hospital at Westmead, Sydney (Australia) and Discipline of Paediatrics and Child Health, Faculty of Medicine, University of Sydney, Sydney (Australia)]. E-mail: AaronS@chw.edu.au; Little, David G. [Department of Orthopaedic Research and Biotechnology, Children's Hospital at Westmead, Sydney (Australia); Discipline of Paediatrics and Child Health, Faculty of Medicine, University of Sydney, Sydney (Australia)

2005-12-16

67

Detection by Transit Photometry  

NASA Technical Reports Server (NTRS)

A periodic sequence of planetary transits provides a valid detection of an orbiting planet and provides the relative size of the planet and its orbital period. Ancillary measurements of the stellar spectrum and the variations of the star's radial velocity or position combined with stellar models allow the absolute size of the planet and its mass to be obtained. The results of this approach have already shown that the planet orbiting HD209458 has only 70% of the mass of Jupiter, but is nearly 50% larger in radius. Based on models of planetary structure, these results imply that the planet must have spent most of its lifetime so close to the star that it has not been able to cool and contract as have the giant planets in our Solar System. Thus its density is much less than Jupiter and Saturn and is actually less than that of water; i.e., about 0.4 gr/cu cm. If more sensitive measurements of the light curve of stars with closely orbiting planets can be made that provide the varying amplitude of the light reflected by the planet at various phases in its orbit, then characteristics of the planetary atmosphere can be obtained. Potentially, these data can identify major molecular species present in the atmosphere and tell us if clouds are present and yield the phase function of the aerosols. Although such detail cannot be obtained for Earth-size planets because their signal amplitudes are too small, it is possible to get data critical to the determination of the structure of extrasolar planetary systems. In particular, the size distributions and their orbital distributions can be measured by the transit photometry missions now in development. The COROT mission should be able to find large terrestrial planets in short-period orbits while the more ambitious Kepler and Eddington missions should be able to detect planets even smaller than the Earth and at orbital distances that place them in the habitable zone of their stars.

Borucki, William J.; Koch, David G.; Jenkins, Jon M.; DeVincenzi, D. (Technical Monitor)

2002-01-01

68

Biofilm Formation by the Fish Pathogen Flavobacterium columnare: Development and Parameters Affecting Surface Attachment  

PubMed Central

Flavobacterium columnare is a bacterial fish pathogen that affects many freshwater species worldwide. The natural reservoir of this pathogen is unknown, but its resilience in closed aquaculture systems posits biofilm as the source of contagion for farmed fish. The objectives of this study were (i) to characterize the dynamics of biofilm formation and morphology under static and flow conditions and (ii) to evaluate the effects of temperature, pH, salinity, hardness, and carbohydrates on biofilm formation. Nineteen F. columnare strains, including representatives of all of the defined genetic groups (genomovars), were compared in this study. The structure of biofilm was characterized by light microscopy, confocal laser scanning microscopy, and scanning electron microscopy. F. columnare was able to attach to and colonize inert surfaces by producing biofilm. Surface colonization started within 6 h postinoculation, and microcolonies were observed within 24 h. Extracellular polysaccharide substances and water channels were observed in mature biofilms (24 to 48 h). A similar time course was observed when F. columnare formed biofilm in microfluidic chambers under flow conditions. The virulence potential of biofilm was confirmed by cutaneous inoculation of channel catfish fingerlings with mature biofilm. Several physicochemical parameters modulate attachment to surfaces, with the largest influence being exerted by hardness, salinity, and the presence of mannose. Maintenance of hardness and salinity values within certain ranges could prevent biofilm formation by F. columnare in aquaculture systems. PMID:23851087

Cai, Wenlong; De La Fuente, Leonardo

2013-01-01

69

Nature of immobilization surface affects antibody specificity to placental alkaline phosphatase.  

PubMed

Retention of native conformation of immobilized protein is essential for various applications including selection and detection of specific recombinant antibodies (scFvs). Placental alkaline phosphatase (PAP), an onco-fetal antigen expressed on the surface of several tumors, was immobilized on supermagnetic particles for selection of recombinant antibodies from a human phage display antibody library. The isolated antibodies were found to be cross-reactive to either of the isozymes of alkaline phosphatase, i.e., bone alkaline phosphatase (BAP) or intestinal alkaline phosphatase (IAP) and could not be used for tumor targeting. A specific anti-PAP monoclonal antibody H17E2 was tested for retention of specificity under these conditions. Binding of the antibody to magnetic beads conjugated IAP and BAP along with PAP and the ability of the two isozymes to inhibit its binding to PAP depicted the loss of isozyme specificity of the antibody. However, the antibody retained its specificity to PAP immobilized on polyvinyl chloride (PVC) surface. Enzyme activity was observed on both surfaces. This demonstrates that nature of immobilization may affect antigen-antibody binding in subtle ways, resulting in alteration of conformation of the epitopes. This may have consequences for determining the specificity of antibody binding for proteins that share a high degree of homology. PMID:25321174

Kumar, Mukesh; Khan, Imran; Sinha, Subrata

2015-01-01

70

PHOTOM: Photometry of digitized images  

NASA Astrophysics Data System (ADS)

PHOTOM performs photometry of digitized images. It has two basic modes of operation: using an interactive display to specify the positions for the measurements, or obtaining those positions from a file. In both modes of operation PHOTOM performs photometry using either the traditional aperture method or via optimal extraction. When using the traditional aperture extraction method the target aperture can be circular or elliptical and its size and shape can be varied interactively on the display, or by entering values from the keyboard. Both methods allow the background sky level to be either sampled interactively by the manual positioning of an aperture, or automatically from an annulus surrounding the target object. PHOTOM is the photometry backend for the GAIA tool (ascl:1403.024) and is part of the Starlink software collection (ascl:1110.012).

Eaton, Nicholas; Draper, Peter W.; Allan, Alasdair; Naylor, Tim; Mukai, Koji; Currie, Malcolm J.; McCaughrean, Mark

2014-05-01

71

Factors affecting use of CR-39 surface monitor technology to estimate past exposure to indoor radon.  

PubMed

In an epidemiologic study investigating influences of life-style and environment on lung cancer risk, CR-39 alpha-particle detectors, identified here as surface monitors, were affixed to subjects' selected household glass, ceramic, or enameled objects to measure residual radioactivity form embedded radon (Rn) decay products. The purpose was to estimate past cumulative indoor Rn concentrations to which the object was exposed to infer past exposures of the subjects. This approach was used to supplement exposure information obtained by methods traditionally used in Rn epidemiologic studies. In addition, surface monitors were affixed to objects of selected study subjects with complete exposure information to evaluate whether surface monitors provided estimates of cumulative past residual Rn exposure comparable to estimates obtained from year-long, ambient alpha track-etch measurements in each present and previous residence. These ambient measurements were time-weighted to estimate integrated exposure of objects and were adjusted for decay and ingrowth so as to be comparable to surface monitor measurements. A regression relationship was estimated between the two estimates of cumulative RN exposure. Surface monitor measurements had a satisfactory correlation (0.63) with adjusted ambient Rn measurements for new, nonceramic objects. Although not included in the study design, factors that might affect use of the technology were also investigated. Regression relationships were compared in graduated smoking environment (as judged by the subjects) to investigate possible differential plate out of radon progeny. In addition, regression relationships for windows were compared with those for other objects to investigate whether there was a significant difference between windows and other objects. It has been suggested that windows may have a higher plate out rate because of locally increased air flow. Results suggested that surface monitor information was useful to fill time gaps in estimates of historical radon exposure data obtained by ambient measurements. Glass samples provided the best correlation. Ceramic materials sometimes provided excessively high radon estimates, probably due to glazes that contained significant uranium or thorium. Due to small sample sizes, investigations of other factors were inconclusive. PMID:9087863

Mahaffey, J A; Parkhurst, M A; Hui, T E; Brownson, R C; Alavanja, M C

1996-01-01

72

UBVR and Hubble Space Telescope Mid-Ultraviolet and Near-Infrared Surface Photometry and Radial Color Gradients of Late-Type, Irregular, and Peculiar Galaxies  

NASA Astrophysics Data System (ADS)

We introduce a data set of 142 mostly late-type spiral, irregular, and peculiar (interacting or merging) nearby galaxies observed in UBVR at the Vatican Advanced Technology Telescope (VATT), and we present an analysis of their radial color gradients. We confirm that nearby elliptical and early- to mid-type spiral galaxies show either no or only small color gradients, becoming slightly bluer with radius. In contrast, we find that late-type spiral, irregular, peculiar, and merging galaxies become on average redder with increasing distance from the center. The scatter in radial color gradient trends increases toward later Hubble type. As a preliminary analysis of a larger data set obtained with the Hubble Space Telescope (HST), we also analyze the color gradients of six nearby galaxies observed with NICMOS in the near-IR (H) and with WFPC2 in the mid-UV (F300W) and red (F814W). We discuss the possible implications of these results on galaxy formation and compare our nearby galaxy color gradients to those at high redshift. We present examples of images and UBVR radial surface brightness and color profiles, as well as of the tables of measurements; the full atlas and tables are published in the electronic edition only. Based on observations made 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., under NASA contract NAS 5-26555. These observations are associated with programs 8645, 9124, and 9824.

Taylor, Violet A.; Jansen, Rolf A.; Windhorst, Rogier A.; Odewahn, Stephen C.; Hibbard, John E.

2005-09-01

73

Parameters Affecting Spore Recovery from Wipes Used in Biological Surface Sampling ? †  

PubMed Central

The need for the precise and reliable collection of potential biothreat contaminants has motivated research in developing a better understanding of the variability in biological surface sampling methods. In this context, the objective of this work was to determine parameters affecting the efficiency of extracting Bacillus anthracis Sterne spores from commonly used wipe sampling materials and to describe performance using the interfacial energy concept. In addition, surface thermodynamics was applied to understand and predict surface sampling performance. Wipe materials were directly inoculated with known concentrations of B. anthracis spores and placed into extraction solutions, followed by sonication or vortexing. Experimental factors investigated included wipe material (polyester, cotton, and polyester-rayon), extraction solution (sterile deionized water [H2O], deionized water with 0.04% Tween 80 [H2O-T], phosphate-buffered saline [PBS], and PBS with 0.04% Tween 80 [PBST]), and physical dissociation method (vortexing or sonication). The most efficient extraction from wipes was observed for solutions containing the nonionic surfactant Tween 80. The increase in extraction efficiency due to surfactant addition was attributed to an attractive interfacial energy between Tween 80 and the centrifuge tube wall, which prevented spore adhesion. Extraction solution significantly impacted the extraction efficiency, as determined by statistical analysis (P < 0.05). Moreover, the extraction solution was the most important factor in extraction performance, followed by the wipe material. Polyester-rayon was the most efficient wipe material for releasing spores into solution by rank; however, no statistically significant difference between polyester-rayon and cotton was observed (P > 0.05). Vortexing provided higher spore recovery in H2O and H2O-T than sonication, when all three wipe materials and the reference control were considered (P < 0.05). PMID:21296945

Da Silva, Sandra M.; Filliben, James J.; Morrow, Jayne B.

2011-01-01

74

PSF Photometry Lecture April XX 2004  

E-print Network

PSF Photometry Lecture April XX 2004 Vitaliy Fadeyev Why do PSF-fitting The simple aperture photometry has an assumption of linearly-varying background in the aperture's vicinity. Choice of (optimal Photometry Lecture April XX 2004 Vitaliy Fadeyev Crowded field example Even when nominally well separated

Masci, Frank

75

TCP'S USER MANUAL REAL TIME PHOTOMETRY (RTP)  

E-print Network

TCP'S USER MANUAL REAL TIME PHOTOMETRY (RTP) Last modified: 2011-09-20 This version by: Jorge manual ­ Real Time Photometry (RTP) 20/09/2011 2 1. INTRODUCTION CCD images normally require a lot of calibration work to be rendered useful for high precision photometry. It is therefore not unusual to spend

76

CCD Photometry of Gliese 372  

NASA Astrophysics Data System (ADS)

We present optical photometry of the M-dwarf binary Gliese 372. We have searched for the predicted eclipses of this binary (Harlow 1996) using a 16-inch telescope and a CCD camera built from "The CCD Camera Cookbook." We set limits on the presence of eclipses, and on the photometric variability outside of eclipse.

Ramseyer, T. F.; Davis, C.; Lasley, C.; Leonard, C.; Portoni, A.

1997-05-01

77

Affine Structure and Photometry  

Microsoft Academic Search

Motion of an observer relative to objects in a scene provides information about the structure of the scene. Changing patterns of shading due to motion relative to the light source provide information about surface structure, albedos, and light sources. One can stratify this photometric information into affine, unitary, and metric structure, much like the stratification of structure from motion. For

Ruth Rosenholtz; Jan J. Koenderink

1996-01-01

78

Sorption processes affecting arsenic solubility in oxidized surface sediments from Tulare Lake Bed, California  

USGS Publications Warehouse

Elevated concentrations of arsenic (As) in shallow groundwater in Tulare Basin pose an environmental risk because of the carcinogenic properties of As and the potential for its migration to deep aquifers that could serve as a future drinking water source. Adsorption and desorption are hypothesized to be the major processes controlling As solubility in oxidized surface sediments where arsenate [As(V)] is dominant. This study examined the relationship between sorption processes and arsenic solubility in shallow sediments from the dry Tulare Lake bed by determining sorption isotherms, pH effect on solubility, and desorption-readsorption behavior (hysteresis), and by using a surface complexation model to describe sorption. The sediments showed a high capacity to adsorb As(V). Estimates of the maximum adsorption capacity were 92 mg As kg- 1 at pH 7.5 and 70 mg As kg- 1 at pH 8.5 obtained using the Langmuir adsorption isotherm. Soluble arsenic [> 97% As(V)] did not increase dramatically until above pH 10. In the native pH range (7.5-8.5), soluble As concentrations were close to the lowest, indicating that As was strongly retained on the sediment. A surface complexation model, the constant capacitance model, was able to provide a simultaneous fit to both adsorption isotherms (pH 7.5 and 8.5) and the adsorption envelope (pH effect on soluble As), although the data ranges are one order of magnitude different. A hysteresis phenomenon between As adsorbed on the sediment and As in solution phase was observed in the desorption-readsorption processes and differs from conventional hysteresis observed in adsorption-desorption processes. The cause is most likely due to modification of adsorbent surfaces in sediment samples upon extensive extractions (or desorption). The significance of the hysteresis phenomenon in affecting As solubility and mobility may be better understood by further microscopic studies of As interaction mechanisms with sediments subjected to extensive leaching in natural environments. ?? 2006 Elsevier B.V. All rights reserved.

Gao, S.; Goldberg, S.; Herbel, M.J.; Chalmers, A.T.; Fujii, R.; Tanji, K.K.

2006-01-01

79

UBVRI photometry of red stars  

NASA Astrophysics Data System (ADS)

A total of 50 Mira- and SR-type red variable stars were observed by means of the photoelectric photometry UBVRI Kron-Cousins system. In addition, 15 nearby red dwarf stars having spectral subtypes similar to those of Mira stars at maximum were observed in order to show that the conversion of the natural system into the Landolt (1983) standard system can be made for stars as red as the Mira variables, in spite of the shortage of standard late M-type stars. The relationship function and spectral type-color index scale on the Johnson system was converted into the present system. By means of VRI photometry, the spectral subtype can immediately be determined in different phases of the light curve. SR variables have the same color indices and spectral subclasses as Mira variables.

Celis S., L.

1986-03-01

80

Water-Induced Reconstruction that Affects Mobile Ions on the Surface of Calcite Treavor A. Kendall and Scot T. Martin*  

E-print Network

Water-Induced Reconstruction that Affects Mobile Ions on the Surface of Calcite Treavor A. Kendall is exchanged between them and that both are loosely bound. Complementing the topographic images, polarization heights are simultaneously measured by polarization-force microscopy. The polarization heights

81

Asteroid photometry program at Modra observatory  

NASA Astrophysics Data System (ADS)

Description of the starting CCD photometry program, parallel to NEO (Near-Earth Object) follow-up, at Modra observatory is given, targeting asteroids, especially NEO, in an effort to extend the database of their physical characteristics. With the gradual increase of observation time for photometry, there is a need for automated processing of data and observation planning. Custom photometry software implemented in Java is explained and comparison of different reduction techniques provided.

Világi, J.

2002-11-01

82

Some Environmental Factors Affecting Surface Coating Formation with Lubricating Oil Additives  

Microsoft Academic Search

Dynamic friction and static immersion tests in which oil temperature was varied and dynamic friction tests in which load was varied have been run on steel balls with oil blends containing seven commercial additives. Analyses of the ball surfaces by X-ray fluorescence have shown that significant surface coating formation is initiated at calculated surface temperatures of from 250 to 350

Fred G. Rounds

1966-01-01

83

How surface roughness affects the angular dependence of the sputtering yield , A. Hassanein  

E-print Network

Center for Materials under Extreme Environment, School of Nuclear Engineering, Purdue University, West fractal ITMC code a b s t r a c t Comprehensive model is developed to study the impact of surface of exact self-similar fractals, we developed a new method to describe the surfaces. Random fractal surfaces

Harilal, S. S.

84

Analysing Thermal Response Test Data Affected by Groundwater Flow and Surface Temperature Change  

NASA Astrophysics Data System (ADS)

Tests that record the underground temperature variation due to a constant heat injected into a borehole (or extracted from it) by means of a carrier fluid are routinely performed to infer subsurface thermal conductivity and borehole thermal resistance, which are needed to size geothermal heat pump systems. The most popular model to analyse temperature-time curves obtained from these tests is the infinite line source (ILS). This model gives appropriate estimations of thermal parameters only if particular hydro-geological conditions are fulfilled. Several flaws can however affect data interpretation with ILS, which is based on strong assumptions like those of a purely conductive heat transfer regime in a homogeneous medium, no vertical heat flow and infinite length of the borehole. Other drawbacks can arise from the difficulty in the proper thermal insulation of the test equipment, and consequently with oscillations of the carrier fluid temperature due to surface temperature changes. In this paper, we focused on the treatment of thermal response test data when both advection and periodic changes of surface temperature occur. We used a moving line source model to simulate temperature-time signals under different hypothesis of Darcy velocity and thermal properties. A random noise was added to the signal in order to mimic high frequency disturbances, possibly caused by equipment operating conditions and/or geological variability. The subsurface thermal conductivity, the Darcy velocity and the borehole thermal resistance were inferred by minimising the root mean square error between the synthetic dataset and the theoretical model. The optimisation was carried out with the Nelder-Mead algorithm, and thermal and hydraulic properties were determined by iterative reprocessing according to a trial-and-error procedure. The inferred thermal and hydraulic parameters are well consistent with the 'a priory' values, and the presence of noise in the synthetic data does not produce instability. The same optimisation procedure was also applied to interpret the synthetic signal with the ILS model. In case of Darcy velocity of the order of 10-6 m s-1, ILS largely overestimates thermal conductivity. The optimisation analysis was then applied to real thermal response tests carried out in boreholes drilled in sedimentary formation aquifers, whose volume heat capacity was assumed to be known. These data showed a periodic offset in the recorded temperature-time series. A Fourier analysis allowed the recognition of harmonic contributions with period of about 12 and 24 hours. These oscillations appeared to be coherent with the data of air temperature change recorded at the test sites. The temperature-time curves were then filtered to remove the disturbing spectral components associated to a non-optimal thermostatic behaviour of the apparatus. This produced reliable estimates of thermal conductivity, Darcy velocity and borehole thermal resistance. The magnitude of the inferred groundwater flow was also checked by means of an independent method based on the analysis of temperature-depth logs recorded prior to the thermal tests, under thermal equilibrium conditions.

Verdoya, Massimo; Imitazione, Gianmario; Chiozzi, Paolo; Orsi, Marco; Armadillo, Egidio

2014-05-01

85

SPA, "The Stellar Photometry Assistant"  

NASA Astrophysics Data System (ADS)

SPA is a stand alone software package for high speed photometry reduction and analysis. The goal of SPA is to be simple, powerful and intuitive. SPA was born out of complications studying the pulsating DB white dwarf EC20058-5234 (QuTel) due to the proximity of its companions. SPA addresses the Whole Earth Telescope's (Nather et al. 1990) demand for large scale rapid data reduction from multiple sites. SPA is being developed in MATLAB by the Delaware Asteroseismic Research Center (DARC) in collaboration with the University of Delaware and the Mount Cuba Astronomical Observatory.

Dalessio, J.; Provencal, J. L.; Shipman, H. L.

2009-06-01

86

The Panchromatic Hubble Andromeda Treasury. X. Ultraviolet to Infrared Photometry of 117 Million Equidistant Stars  

NASA Astrophysics Data System (ADS)

We have measured stellar photometry with the Hubble Space Telescope Wide Field Camera 3 (WFC3) and Advanced Camera for Surveys in near ultraviolet (F275W, F336W), optical (F475W, F814W), and near infrared (F110W, F160W) bands for 117 million resolved stars in M31. As part of the Panchromatic Hubble Andromeda Treasury survey, we measured photometry with simultaneous point-spread function (PSF) fitting across all bands and at all source positions after precise astrometric image alignment (<5-10 mas accuracy). In the outer disk, the photometry reaches a completeness-limited depth of F475W ~ 28, while in the crowded, high surface brightness bulge, the photometry reaches F475W ~ 25. We find that simultaneous photometry and optimized measurement parameters significantly increase the detection limit of the lowest-resolution filters (WFC3/IR) providing color-magnitude diagrams (CMDs) that are up to 2.5 mag deeper when compared with CMDs from WFC3/IR photometry alone. We present extensive analysis of the data quality including comparisons of luminosity functions and repeat measurements, and we use artificial star tests to quantify photometric completeness, uncertainties and biases. We find that the largest sources of systematic error in the photometry are due to spatial variations in the PSF models and charge transfer efficiency corrections. This stellar catalog is the largest ever produced for equidistant sources, and is publicly available for download by the community.

Williams, Benjamin F.; Lang, Dustin; Dalcanton, Julianne J.; Dolphin, Andrew E.; Weisz, Daniel R.; Bell, Eric F.; Bianchi, Luciana; Byler, Nell; Gilbert, Karoline M.; Girardi, Léo; Gordon, Karl; Gregersen, Dylan; Johnson, L. C.; Kalirai, Jason; Lauer, Tod R.; Monachesi, Antonela; Rosenfield, Philip; Seth, Anil; Skillman, Eva

2014-11-01

87

Asteroid Analysis Using Lightcurve Photometry  

NASA Astrophysics Data System (ADS)

During the summer of 2011 data was taken of asteroid 3807 Pagels, a mid-sized asteroid located in the main asteroid belt in order to identify its rotational period. The asteroid 3807 Pagels is a poorly studied main belt asteroid that has little information recorded about its physical features. Time-series photometry of 3807 Pagels was obtained with a 16-inch telescope connected to a CCD camera located at the Texas A&M University - Commerce Observatory. CCD images were taken continuously with five minute exposure times through the standard broadband V filter. The data was then analyzed using the MPO Canopus program which utilized comparison stars within each CCD image to determine differential photometry and then generate a lightcurve for the asteroid. The final lightcurve did not show a complete rotational period for the asteroid. Thus, additional observations are needed in order to precisely determine 3807 Pagels rotational period. This research is the first steps of a long process of determining more information about the many mid-sized asteroids located in the asteroid belt for the potential of being able to classify these asteroids by their physical characteristics.

Zimmerman, Jessica

2011-10-01

88

Fast photometry with small telescopes  

NASA Astrophysics Data System (ADS)

Facility instruments on major telescopes rarely provide photometry on timescales into the sub-second range. The development of dedicated high-time resolution detectors that could be attached as guest instruments was therefore natural to follow up with optical observations on many highly time variable astronomical objects. Such sources were often discovered first in the radio range (e.g. pulsars, quasars) or with X- and gamma-ray satellites (X-ray binaries, cataclysmic variables, gamma-ray bursts). Although telescopes in the 4 - 8m class would be nice to have for high-time resolution astronomy (HTRA) the access is often oversubscribed. Many currently active HTRA instruments were started on smaller telescopes in the 1-3m class, which provide the flexibility and observation time needed for the observation of highly variable stars. We describe the basic detector types, i.e. fast imaging or photon counting, and current projects. Based on our experience with the fast timing photo-polarimeter OPTIMA (Optical Timing Analyzer), we review some observational constraints on meter-class telescopes. We demonstrate the 'scientific power' of very fast photometry, done with OPTIMA and similar systems on small telescopes, with selected results for a black hole binary, an optical transient magnetar, and the Crab pulsar. %

Kanbach, G.; Rau, A.; S?owikowska, A.

2014-03-01

89

Induction effects for heterochromatic brightness matching, heterochromatic flicker photometry,  

E-print Network

Induction effects for heterochromatic brightness matching, heterochromatic flicker photometry flicker photometry (HFP), and minimally distinct border (MDB). For HBM, subjects varied the relative compared with those obtained on two other tasks: hetero- chromatic flicker photometry (HFP) and minimally

Dobkins, Karen R.

90

Nanoscale Roughness and Morphology Affect the IsoElectric Point of Titania Surfaces  

PubMed Central

We report on the systematic investigation of the role of surface nanoscale roughness and morphology on the charging behaviour of nanostructured titania (TiO2) surfaces in aqueous solutions. IsoElectric Points (IEPs) of surfaces have been characterized by direct measurement of the electrostatic double layer interactions between titania surfaces and the micrometer-sized spherical silica probe of an atomic force microscope in NaCl aqueous electrolyte. The use of a colloidal probe provides well-defined interaction geometry and allows effectively probing the overall effect of nanoscale morphology. By using supersonic cluster beam deposition to fabricate nanostructured titania films, we achieved a quantitative control over the surface morphological parameters. We performed a systematical exploration of the electrical double layer properties in different interaction regimes characterized by different ratios of characteristic nanometric lengths of the system: the surface rms roughness Rq, the correlation length ? and the Debye length ?D. We observed a remarkable reduction by several pH units of IEP on rough nanostructured surfaces, with respect to flat crystalline rutile TiO2. In order to explain the observed behavior of IEP, we consider the roughness-induced self-overlap of the electrical double layers as a potential source of deviation from the trend expected for flat surfaces. PMID:23874708

Borghi, Francesca; Vyas, Varun; Podestà, Alessandro; Milani, Paolo

2013-01-01

91

Affecting surface chirality via multicomponent adsorption of chiral and achiral molecules.  

PubMed

Here we report on the apparent reduction in surface chirality upon co-assembling a chiral and achiral molecule into a physisorbed self-assembled monolayer at the liquid/solid interface as revealed by scanning tunneling microscopy (STM). Chiral OPV with achiral thymine gives rise to surface-confined supramolecular diastereomers. PMID:25154626

Guo, Zongxia; De Cat, Inge; Van Averbeke, Bernard; Lin, Jianbin; Wang, Guojie; Xu, Hong; Lazzaroni, Roberto; Beljonne, David; Schenning, Albertus P H J; De Feyter, Steven

2014-10-14

92

Surface and Subsurface Geologic Risk Factors to Ground Water Affecting Brownfield Redevelopment Potential  

Microsoft Academic Search

brownfields. The model is derived from a space and time conceptual framework that identifies and measures the surface and subsurface risk the substances released on and just below the surface factors present at brownfield sites. The model then combines these by human activity and their interactions with the near- factors with a contamination extent multiplier at each site to create

Martin M. Kaufman; Kent S. Murray; Daniel T. Rogers

2003-01-01

93

An optimal extraction algorithm for imaging photometry  

Microsoft Academic Search

This paper is primarily an investigation of whether the `optimal extraction' techniques used in CCD spectroscopy can be applied to imaging photometry. It is found that using such techniques provides a gain of around 10 per cent in signal-to-noise ratio over normal aperture photometry. Formally, it is shown to be equivalent to profile fitting, but offers advantages of robust error

Tim Naylor

1998-01-01

94

Substrate material affects wettability of surfaces coated and sintered with silica nanoparticles  

NASA Astrophysics Data System (ADS)

Silica nanoparticles coating and sintering is a widely-used approach for creating hydrophobic and superhydrophobic surfaces. The role of substrate material in this process, however, has not been thoroughly investigated. In this work, the role of substrate material is examined by measuring surface wettability of three different substrate materials (glass, polyimide and copper) under systematically varied conditions. These surfaces are modulated from hydrophilic (water contact angle (WCA) < 90°) to superhydrophobic (WCA > 150°) by coating and sintering silica nanoparticles, followed by assembling a layer of fluorine compound. Static WCA characterization shows that surface wettability is not solely dependent on the concentration of the coating colloidal, but is also on the substrate material. In particular, copper substrate exhibits a larger WCA than glass and polyimide substrates. Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS) and Atomic Force Microscopy (AFM) characterizations show that the substrate material-dependent wettability is attributed to thermal-induced nanostructures on the copper surface, which contributes to the hierarchical micro-/nano- topography. This finding is important for designing hydrophobic/superhydrophobic surfaces comprised of different materials, especially those that would experience thermal cycles in surface functionalization and subsequent use.

Wei, Kang; Zeng, Hansong; Zhao, Yi

2013-05-01

95

The interaction between the tennis court and the player: how does surface affect leg stiffness?  

PubMed

An adequate level of leg stiffness is necessary for an optimal tennis performance and leg stiffness should be adapted to frequently changing surfaces as tennis players usually play on different courts. The aim of this study was to evaluate leg stiffness in competitive tennis players on different court surfaces. Ten healthy competitive tennis players (nine men and one woman; mean age = 17.6 +/- 3.2 years) underwent leg stiffness testing by modeling the vertical ground reaction force using an optical system. Flight time and contact time were determined during hopping on two different tennis court surfaces (clay and acrylic). No significant difference was found in the flight time, contact time, and jump height between the surfaces. No significant difference in leg stiffness was found between the surfaces (18.25 +/- 5.8 and 19.27 +/- 4.9 kN/m for clay and acrylic, respectively; p = 0.28). This study demonstrated that contact time and flight time as well as leg stiffness of tennis players remained unchanged when hopping on two different tennis surfaces. Results of this research provide objective data regarding the tennis-specific loading of the locomotor system and proper mechanical adaptation of the player on different surfaces, which may be useful for testing protocols and planning training programs. PMID:23724608

Maquirriain, Javier

2013-03-01

96

Development and characterization of integrating sphere for photometry and radiometry measurement  

NASA Astrophysics Data System (ADS)

Integrating Sphere (IS) is an instrument formed a cavity sphere with its inner surface act as a Lambertian reflector. IS is needed in many optical measurements which involves a high diffused reflection. In addition, IS very essential in photometry and radiometry measurement system. However, currently, IS is still an imported product which considered very expensive. The material for the sphere and inner surface coating affect the performance of the IS systems. Therefore, the main challenges in designing IS are the material engineering for the sphere and the procedure for the inner surface coating. The inner surface was coated using BaSO4 which has a low absorption and high diffuse reflection. Spectral responses of the IS system was characterized using USB2000+ and calibrated using a standard Spectralon from ocean optic. The obtained IS system used an inner surface coating from a mixed 80% Barium Sulfate (BaSO4) and 20% Nippon Elastex paint which yield a reflection factor ? = 0.955 and amplification factor M=10.69. The validation was conducted using an emitter with known specification from Luxeon of LXHL-DW01 which produced light flux 40.5 lumen with injection current 350 mA and junction temperature Tj 25°C.

Wibawa, Bambang Mukti; Mujahid, Abdul Al; Mindara, Jajat Yuda; Panatarani, Camellia; Joni, I. Made; Siregar, Rustam Efendi

2013-09-01

97

Cloning and Analysis of a Candida albicans Gene That Affects Cell Surface Hydrophobicity  

Microsoft Academic Search

The opportunistic pathogenic yeast Candida albicans exhibits growth phase-dependent changes in cell surface hydrophobicity, which has been correlated with adhesion to host tissues. Cell wall proteins that might contribute to the cell surface hydrophobicity phenotype were released by limited glucanase digestion. These proteins were initially characterized by their rates of retention during hydrophobic interaction chromatogra- phy-high-performance liquid chromatography and used

DAVID R. SINGLETON; JAMES MASUOKA; KEVIN C. HAZEN

2001-01-01

98

Changes in droplet surface tension affect the observed hygroscopicity of photochemically aged biomass burning aerosol.  

PubMed

This study examines the hygroscopic and surface tension properties as a function of photochemical aging of the aerosol emissions from biomass burning. Experiments were conducted in a chamber setting at the UC-Riverside Center for Environmental Research and Technology (CE-CERT) Atmospheric Processes Lab using two biomass fuel sources, manzanita and chamise. Cloud condensation nuclei (CCN) measurements and off-line filter sample analysis were conducted. The water-soluble organic carbon content and surface tension of the extracted filter samples were measured. Surface tension information was then examined with Köhler theory analysis to calculate the hygroscopicity parameter, ?. Laboratory measurement of biomass burning smoke from two chaparral fuels is shown to depress the surface tension of water by 30% or more at organic matter concentrations relevant at droplet activation. Accounting for surface tension depression can lower the calculated ? by a factor of 2. This work provides evidence for surface tension depression in an important aerosol system and may provide closure for differing sub- and supersaturated ? measurements. PMID:23957441

Giordano, Michael R; Short, Daniel Z; Hosseini, Seyedehsan; Lichtenberg, William; Asa-Awuku, Akua A

2013-10-01

99

Factors affecting the spontaneous motion of condensate drops on superhydrophobic copper surfaces.  

PubMed

The coalescence-induced condensate drop motion on some superhydrophobic surfaces (SHSs) has attracted increasing attention because of its potential applications in sustained dropwise condensation, water collection, anti-icing, and anticorrosion. However, an investigation of the mechanism of such self-propelled motion including the factors for designing such SHSs is still limited. In this article, we fabricated a series of superhydrophobic copper surfaces with nanoribbon structures using wet chemical oxidation followed by fluorization treatment. We then systematically studied the influence of surface roughness and the chemical properties of as-prepared surfaces on the spontaneous motion of condensate drops. We quantified the "frequency" of the condensate drop motion based on microscopic sequential images and showed that the trend of this frequency varied with the nanoribbon structure and extent of fluorination. More obvious spontaneous condensate drop motion was observed on surfaces with a higher extent of fluorization and nanostructures possessing sufficiently narrow spacing and higher perpendicularity. We attribute this enhanced drop mobility to the stable Cassie state of condensate drops in the dynamic dropwise condensation process that is determined by the nanoscale morphology and local surface energy. PMID:22424422

Feng, Jie; Qin, Zhaoqian; Yao, Shuhuai

2012-04-10

100

Theory of wide-angle photometry from standard stars  

NASA Technical Reports Server (NTRS)

Wide angle celestial structures, such as bright comet tails and nearby galaxies and clusters of galaxies, rely on photographic methods for quantified morphology and photometry, primarily because electronic devices with comparable resolution and sky coverage are beyond current technological capability. The problem of the photometry of extended structures and of how this problem may be overcome through calibration by photometric standard stars is examined. The perfect properties of the ideal field of view are stated in the guise of a radiometric paraxial approximation, in the hope that fields of view of actual telescopes will conform. Fundamental radiometric concepts are worked through before the issue of atmospheric attenuation is addressed. The independence of observed atmospheric extinction and surface brightness leads off the quest for formal solutions to the problem of surface photometry. Methods and problems of solution are discussed. The spectre is confronted in the spirit of standard stars and shown to be chimerical in that light, provided certain rituals are adopted. After a brief discussion of Baker-Sampson polynomials and the vexing issue of saturation, a pursuit is made of actual numbers to be expected in real cases. While the numbers crunched are gathered ex nihilo, they demonstrate the feasibility of Newton's method in the solution of this overdetermined, nonlinear, least square, multiparametric, photometric problem.

Usher, Peter D.

1989-01-01

101

Abiotic Factors Affecting the Persistence of Avian Influenza Virus in Surface Waters of Waterfowl Habitats  

PubMed Central

Avian influenza (AI) virus can remain infectious in water for months, and virus-contaminated surface water is considered to be a source of infection within wild waterfowl populations. Previous work has characterized the effects of pH, salinity, and temperature on viral persistence in water, but most of that work was done with modified distilled water. The objective of this study was to identify the abiotic factors that influence the duration of AI virus persistence in natural surface water. Surface water samples were collected from 38 waterfowl habitats distributed across the United States. Samples were submitted to the U.S. Geological Survey National Water Quality Laboratory for chemical analysis and the University of Georgia for viral reduction time analysis. Samples were filtered with 0.22-?m filters, and the durations of persistence of three wild-bird-derived influenza A viruses within each water sample at 10, 17, and 28°C were determined. The effects of the surface water physicochemical factors on the duration of AI viral persistence in laboratory experiments were evaluated by multivariable linear regression with robust standard errors. The duration of AI virus persistence was determined to be longest in filtered surface water with a low temperature (<17°C), a neutral-to-basic pH (7.0 to 8.5), low salinity (<0.5 ppt), and a low ammonia concentration (<0.5 mg/liter). Our results also highlighted potential strain-related variation in the stability of AI virus in surface water. These results bring us closer to being able to predict the duration of AI virus persistence in surface water of waterfowl habitats. PMID:24584247

Dalton, Melinda S.; Cressler, Alan M.; Berghaus, Roy D.; Stallknecht, David E.

2014-01-01

102

Nanoscale surface roughness affects low Reynolds number flow: Experiments and modeling  

NASA Astrophysics Data System (ADS)

Most micro-channel fabrication strategies generate nano-to-micro-scale, stochastic surface roughness. This inherent stochasticity can potentially be harnessed to direct microfluidic operations such as self-cleaning behavior and localized mixing. This work investigates the effect of stochastic nanoscale roughness on low to moderate Reynolds number Newtonian flow using concurrent modeling and experiments. We fabricate a microscopic channel with tailored hydrofluoric-acid-etched rough surfaces. Optical profilometry and micro-particle-image-velocimetry (micro-PIV) are used to characterize the surface roughness and flow field and is integrated with direct numerical simulation that resolves effects of nanoscale roughness. Results indicate that nanoscale roughness causes flow perturbations that extend up to the mid-plane and is insensitive to flow-rates.

Jaeger, R.; Ren, J.; Xie, Y.; Sundararajan, S.; Olsen, M. G.; Ganapathysubramanian, B.

2012-10-01

103

How linear surface waves are affected by a current with constant vorticity  

NASA Astrophysics Data System (ADS)

The interaction of surface waves with Couette-type current with uniform vorticity is a well suited problem for students approaching the theory of surface waves. The problem, although mathematically simple, contains rich physics, and is moreover important in several situations from oceanography and marine technology to microfluidics. We here lay out a simple two-dimensional theory of waves propagating upon a basic flow of uniform vorticity of constant depth. The dispersion relation is found, showing how the shearing current introduces different phase velocities for upstream and downstream propagating waves. The role of the surface tension is discussed and applied to the case of a wave pattern created by a moving source, stationary as seen by the source. We conclude by discussing how the average potential and kinetic energies are no longer equal in the presence of shear.

Ellingsen, Simen Å.; Brevik, Iver

2014-03-01

104

Polarimetric Retrievals of Surface and Cirrus Clouds Properties in the Region Affected by the Deepwater Horizon Oil Spill  

NASA Technical Reports Server (NTRS)

In 2010, the Goddard Institute for Space Studies (GISS) Research Scanning Polarimeter (RSP) performed several aerial surveys over the region affected by the oil spill caused by the explosion of the Deepwater Horizon offshore platform. The instrument was deployed on the NASA Langley B200 aircraft together with the High Spectral Resolution Lidar (HSRL), which provides information on the distribution of the aerosol layers beneath the aircraft, including an accurate estimate of aerosol optical depth. This work illustrates the merits of polarization measurements in detecting variations of ocean surface properties linked to the presence of an oil slick. In particular, we make use of the degree of linear polarization in the glint region, which is severely affected by variations in the refractive index but insensitive to the waviness of the water surface. Alterations in the surface optical properties are therefore expected to directly affect the polarization response of the RSP channel at 2264 nm, where both molecular and aerosol scattering are negligible and virtually all of the observed signal is generated via Fresnel reflection at the surface. The glint profile at this wavelength is fitted with a model which can optimally estimate refractive index, wind speed and direction, together with aircraft attitude variations affecting the viewing geometry. The retrieved refractive index markedly increases over oil-contaminated waters, while the apparent wind speed is significantly lower than in adjacent uncontaminated areas, suggesting that the slick dampens high-frequency components of the ocean wave spectrum. The constraint on surface reflectance provided by the short-wave infrared channels is a cornerstone of established procedures to retrieve atmospheric aerosol microphysical parameters based on the inversion of the RSP multispectral measurements. This retrieval, which benefits from the ancillary information provided by the HSRL, was in this specific case hampered by prohibitive variability in atmospheric conditions (very inhomogeneous aerosol distribution and cloud cover). Although the results presented for the surface are essentially unaffected, we discuss the results obtained by typing algorithms in sorting the complex mix of aerosol types, and show evidence of oriented ice in cirrus clouds present in the area. In this context, polarization measurements at 1880 nm were used to infer ice habit and cirrus optical depth, which was found in the subvisual/threshold-visible regime, confirming the utility of the aforementioned RSP channel for the remote sensing of even thin cold clouds.

Ottaviani, Matteo; Cairns, Brian; Chowdhary, Jacek; Van Diedenhoven, Bastiaan; Knobelspiesse, Kirk; Hostetler, Chris; Ferrare, Rich; Burton, Sharon; Hair, John; Obland, Michael D.; Rogers, Raymond

2012-01-01

105

Detoxification of Implant Surfaces Affected by Peri-Implant Disease: An Overview of Surgical Methods  

PubMed Central

Purpose. Peri-implantitis is one of the major causes of implant failure. The detoxification of the implant surface is necessary to obtain reosseointegration. The aim of this review was to summarize in vitro and in vivo studies as well as clinical trials that have evaluated surgical approaches for detoxification of the implant body surfaces. Materials and Methods. A literature search was conducted using MEDLINE (PubMed) from 1966 to 2013. The outcome variables were the ability of the therapeutic method to eliminate the biofilm and endotoxins from the implant surface, the changes in clinical parameters, radiographic bone fill, and histological reosseointegration. Results. From 574 articles found, 76 were analyzed. The findings, advantages, and disadvantages of using mechanical, chemical methods and lasers are discussed. Conclusions. Complete elimination of the biofilms is difficult to achieve. All therapies induce changes of the chemical and physical properties of the implant surface. Partial reosseointegration after detoxification has been reported in animals. Combination protocols for surgical treatment of peri-implantitis in humans have shown some positive clinical and radiographic results, but long-term evaluation to evaluate the validity and reliability of the techniques is needed. PMID:23983691

Wilson Jr, Thomas G.

2013-01-01

106

Physiological variables affecting surface film formation by native lamellar body-like pulmonary surfactant particles.  

PubMed

Pulmonary surfactant (PS) is a surface active complex of lipids and proteins that prevents the alveolar structures from collapsing and reduces the work of breathing by lowering the surface tension at the alveolar air-liquid interface (ALI). Surfactant is synthesized by the alveolar type II (AT II) cells, and it is stored in specialized organelles, the lamellar bodies (LBs), as tightly packed lipid bilayers. Upon secretion into the alveolar lining fluid, a large fraction of these particles retain most of their packed lamellar structure, giving rise to the term lamellar body like-particles (LBPs). Due to their stability in aqueous media, freshly secreted LBPs can be harvested from AT II cell preparations. However, when LBPs get in contact with an ALI, they quickly and spontaneously adsorb into a highly organized surface film. In the present study we investigated the adsorptive capacity of LBPs at an ALI under relevant physiological parameters that characterize the alveolar environment in homeostatic or in pathological conditions. Adsorption of LBPs at an ALI is highly sensitive to pH, temperature and albumin concentration and to a relatively lesser extent to changes in osmolarity or Ca(2+) concentrations in the physiological range. Furthermore, proteolysis of LBPs significantly decreases their adsorptive capacity confirming the important role of surfactant proteins in the formation of surface active films. PMID:24582711

Hobi, Nina; Siber, Gerlinde; Bouzas, Virginia; Ravasio, Andrea; Pérez-Gil, Jesus; Haller, Thomas

2014-07-01

107

Domains of surfactant protein A that affect protein oligomerization, lipid structure and surface tension  

Microsoft Academic Search

Surfactant protein A (SP-A) is an abundant protein found in pulmonary surfactant which has been reported to have multiple functions. In this review, we focus on the structural importance of each domain of SP-A in the functions of protein oligomerization, the structural organization of lipids and the surface-active properties of surfactant, with an emphasis on ultrastructural analyses. The N-terminal domain

Nades Palaniyar; Machiko Ikegami; Thomas Korfhagen; Jeffrey Whitsett; Francis X McCormack

2001-01-01

108

Retention of potentially mobile radiocesium in forest surface soils affected by the Fukushima nuclear accident  

PubMed Central

The fate of 137Cs derived from the Fukushima nuclear accident fallout and associated radiological hazards are largely dependent on its mobility in the surface soils of forest ecosystems. Thus, we quantified microbial and adsorptive retentions of 137Cs in forest surface (0–3 cm) soils. The K2SO4 extraction process liberated 2.1%–12.8% of the total 137Cs from the soils. Two soils with a higher content of clay- and silt-sized particles, organic carbon content, and cation exchange capacity showed higher 137Cs extractability. Microbial biomass was observed in all of the soils. However, the 137Cs extractability did not increase after destruction of the microbial biomass by chloroform fumigation, providing no evidence for microbial retention of the Fukushima-fallout 137Cs. The results indicate that uptake of 137Cs by soil microorganisms is less important for retention of potentially mobile 137Cs in the forest surface soils compared to ion-exchange adsorption on non-specific sites provided by abiotic components. PMID:23256039

Koarashi, Jun; Moriya, Koichi; Atarashi-Andoh, Mariko; Matsunaga, Takeshi; Fujita, Hiroki; Nagaoka, Mika

2012-01-01

109

N-acetyl-L-cysteine affects growth, extracellular polysaccharide production, and bacterial biofilm formation on solid surfaces.  

PubMed

N-Acetyl-L-cysteine (NAC) is used in medical treatment of patients with chronic bronchitis. The positive effects of NAC treatment have primarily been attributed to the mucus-dissolving properties of NAC, as well as its ability to decrease biofilm formation, which reduces bacterial infections. Our results suggest that NAC also may be an interesting candidate for use as an agent to reduce and prevent biofilm formation on stainless steel surfaces in environments typical of paper mill plants. Using 10 different bacterial strains isolated from a paper mill, we found that the mode of action of NAC is chemical, as well as biological, in the case of bacterial adhesion to stainless steel surfaces. The initial adhesion of bacteria is dependent on the wettability of the substratum. NAC was shown to bind to stainless steel, increasing the wettability of the surface. Moreover, NAC decreased bacterial adhesion and even detached bacteria that were adhering to stainless steel surfaces. Growth of various bacteria, as monocultures or in a multispecies community, was inhibited at different concentrations of NAC. We also found that there was no detectable degradation of extracellular polysaccharides (EPS) by NAC, indicating that NAC reduced the production of EPS, in most bacteria tested, even at concentrations at which growth was not affected. Altogether, the presence of NAC changes the texture of the biofilm formed and makes NAC an interesting candidate for use as a general inhibitor of formation of bacterial biofilms on stainless steel surfaces. PMID:12902275

Olofsson, Ann-Cathrin; Hermansson, Malte; Elwing, Hans

2003-08-01

110

Surface variations affecting human dental enamel studied using nanomechanical and chemical analysis  

NASA Astrophysics Data System (ADS)

The enamel surface is the interface between the tooth and its ever changing oral environment. Cavity (caries) formation and extrinsic tooth staining are due, respectively, to degradation of the enamel structure under low pH conditions and interactions between salivary pellicle and dietary elements. Both of these occur at the enamel surface and are caused by the local environment changing the chemistry of the surface. The results can be detrimental to the enamel's mechanical integrity and aesthetics. Incipient carious lesions are the precursor to caries and form due to demineralisation of enamel. These carious lesions are a reversible structure where ions (e.g. Ca2+, F -) can diffuse in (remineralisation) to preserve the tooth's structural integrity. This investigation used controlled in vitro demineralisation and remineralisation to study artificial carious lesion formation and repair. The carious lesions were cross-sectioned and characterised using nanoindentation, electron probe micro-analysis and time of flight secondary ion mass spectrometry. Mechanical and chemical maps showed the carious lesion had a significantly reduced hardness and elastic modulus, and the calcium and phosphate content was lower than in sound enamel. Fluoride based remineralisation treatments gave a new phase (possibly fluorohydroxyapatite) within the lesion with mechanical properties higher than sound enamel. The acquired salivary pellicle is a protein-rich film formed by the physisorption of organic molecules in saliva onto the enamel surface. Its functions include lubrication during mastication and chemical protection. However, pellicle proteins react with dietary elements such as polyphenols (tannins in tea) causing a brown stain. This study has used in vitro dynamic nanoindentation and atomic force microscopy to examine normal and stained pellicles formed in vivo. The effects of polyphenols on the pellicle's mechanical properties and morphology have been studied. It was found that the initial adsorption of proteins occurred within 30 seconds of exposure to the oral cavity; fully mature pellicles develop in 2 hours. Polyphenol staining resulted in substantial changes in the morphology and mechanical properties of the pellicle. Specifically, staining gives pellicles consisting of large globules with high surface adhesion and a high loss tangent. These changes help explain why extrinsic stains are difficult to remove abrasively.

Dickinson, Michelle Emma

111

An Introduction to Astronomical Photometry Using CCDs W. Romanishin  

E-print Network

An Introduction to Astronomical Photometry Using CCDs W. Romanishin University of Oklahoma wjr astrophysics major to photometry in the optical region of the spectrum of astronomical objects using CCD telescope time as photometry. That said, it is still obvious that imaging photometry is an important part

Ellingson, Steven W.

112

An Introduction to Astronomical Photometry Using CCDs W. Romanishin  

E-print Network

An Introduction to Astronomical Photometry Using CCDs W. Romanishin University of Oklahoma wjr for the college astrophysics major to photometry in the optical region of the spectrum of astronomical objects telescope time as photometry. That said, it is still obvious that imaging photometry is an important part

Masci, Frank

113

Factors affecting survival of Shigatoxin-producing Escherichia coli on abiotic surfaces.  

PubMed

Shigatoxin-producing Escherichia coli (STEC) causes severe infections, and has been the cause of a number of foodborne outbreaks. Knowledge on the survival of STEC is crucial in order to limit the risk of cross contamination and transfer of STEC to food during processing. In this study survival of STEC and non-STEC on surfaces under various humidities, temperatures and in the presence of different types of soil was investigated. A model system with controlled relative humidity and temperature was established by using saturated salt solutions. All the 12 STEC strains had a reduction in viable count during incubation at 70% RH at 12 degrees C. The reduction was 2-3.5 log and 4.5-5.5 log after 1 and 7 days of incubation, respectively. Surviving cells were observed after 19 days of incubation. The STEC strains were more resistant to desiccation than non-STEC strains. STEC survived better at 12 degrees C, compared to 20 degrees C. The survival of STEC was much lower than the survival of a Staphylococcus simulans strain tested, which showed less than 1 log reduction until day 7 at 70% RH at 12 degrees C, while several STEC strains had comparable survival to a Salmonella Agona strain. The survival of two STEC strains tested was highest at 98% RH. The lowest survival was observed at 85% RH, with better survival at drier conditions. Presence of proteins and glucose protected the cells at dry conditions. Two commercial disinfectants tested at in-use concentration had limited effect (0.8-2.5 log reduction) against STEC on stainless steel, especially for cells incubated at high relative humidity (98% RH). STEC surviving on surfaces in the food industry may impose a risk for cross contamination. Cleaning and use of suitable disinfectants will reduce the survival of STEC, but surfaces should be allowed to dry completely since humid conditions will promote the survival and growth of STEC. PMID:20100628

Møretrø, T; Heir, E; Mo, K R; Habimana, O; Abdelgani, A; Langsrud, S

2010-03-31

114

Solid surface structure affects liquid order at the polystyrene-self-assembled-monolayer interface  

NASA Astrophysics Data System (ADS)

We present a combined x-ray and neutron reflectivity study characterizing the interface between polystyrene (PS) and silanized surfaces. Motivated by the large difference in slip velocity of PS on top of dodecyl-trichlorosilane (DTS) and octadecyl-trichlorosilane (OTS) found in previous studies, these two systems were chosen for the present investigation. The results reveal the molecular conformation of PS on silanized silicon. Differences in the molecular tilt of OTS and DTS are replicated by the adjacent phenyl rings of the PS. We discuss our findings in terms of a potential link between the microscopic interfacial structure and dynamic properties of polymeric liquids at interfaces.

Gutfreund, Philipp; Bäumchen, Oliver; Fetzer, Renate; van der Grinten, Dorothee; Maccarini, Marco; Jacobs, Karin; Zabel, Hartmut; Wolff, Max

2013-01-01

115

The Panchromatic Hubble Andromeda Treasury Survey: UV-IR Photometry of 117 Million Stars  

NASA Astrophysics Data System (ADS)

We have measured resolved stellar photometry using HST/WFC3 and HST/ACS imaging in near ultraviolet (F275W, F336W), optical (F475W, F814W), and near infrared (F110W, F160W) with simultaneous point spread function fitting across all bands at all source positions. All images were aligned to 5-10 milliarcsecond relative accuracy and to 50 milliarcsec global accuracy. In the outer disk, the photometry reaches a completeness-limited depth of F475W~28, while in the crowded, high surface brightness bulge, the photometry reaches F475W~25. We find that simultaneous photometry and optimized measurement parameters significantly increase the detection limit of the lowest resolution filters (WFC3/IR) providing color-magnitude diagrams that are up to 2.5 magnitudes deeper when compared with color-magnitude diagrams from WFC3/IR photometry alone. This stellar catalog is the largest ever produced for equidistant sources, and is publicly available for download by the community. The quality of the photometry catalog, as well as examples of some initial results from model fitting will be discussed. PHAT is supported by HST GO-12055 administered by NASA.

Williams, Benjamin F.; Lang, Dustin; Dalcanton, Julianne; Dolphin, Andrew E.; Weisz, Daniel R.; Johnson, Lent C.; Byler, Nell; Gregersen, Dylan; Seth, Anil; Girardi, Leo; PHAT Survey Team

2015-01-01

116

A new capture fraction method to map how pumpage affects surface water flow  

USGS Publications Warehouse

All groundwater pumped is balanced by removal of water somewhere, initially from storage in the aquifer and later from capture in the form of increase in recharge and decrease in discharge. Capture that results in a loss of water in streams, rivers, and wetlands now is a concern in many parts of the United States. Hydrologists commonly use analytical and numerical approaches to study temporal variations in sources of water to wells for select points of interest. Much can be learned about coupled surface/groundwater systems, however, by looking at the spatial distribution of theoretical capture for select times of interest. Development of maps of capture requires (1) a reasonably well-constructed transient or steady state model of an aquifer with head-dependent flow boundaries representing surface water features or evapotranspiration and (2) an automated procedure to run the model repeatedly and extract results, each time with a well in a different location. This paper presents new methods for simulating and mapping capture using three-dimensional groundwater flow models and presents examples from Arizona, Oregon, and Michigan. Journal compilation ?? 2010 National Ground Water Association. No claim to original US government works.

Leake, S.A.; Reeves, H.W.; Dickinson, J.E.

2010-01-01

117

Surface changes on a landslide affected high bluff in Dunaszekcs? (Hungary)  

NASA Astrophysics Data System (ADS)

This article presents results from the survey conducted on Dunaszekcs? loess bluff after the last major rotational sliding event in 2008. The study area is a region of 25×30 m located on loess bluff close to the recent scarp. The relative elevation change of the surface was surveyed in 2.5×5 m grid network in relation to a marked base point. The survey was conducted using simple equipment such as analogue theodolite and leveller with regular time interval during a year and control measurements were taken after six months. It was assumed that measurements to the nearest cm are sufficient to recognize vertical displacements of the surface. The study focused on identifying the pattern of general vertical movements for the study area by the relative movements of individual points. Our results show significant cm scale vertical displacements. Most of the grid points have a slow decreasing tendency, but close to the scarp a more significant displacement was found. The main character of the spatial pattern is subsidence, which is more definitive on southern part of the study area than the northern part. Our observations correlate with the broader geomorphological characteristics of loess bluffs along the Danube.

Bugya, Titusz; Fábián, Szabolcs Á.; Görcs, Noémi L.; Kovács, István P.; Radvánszky, Bertalan

2011-06-01

118

WFPC2 Stellar Photometry with HSTphot  

NASA Technical Reports Server (NTRS)

HSTphot, a photometry package designed to handle the undersampled PSFs found in WFPC2 images, is introduced and described, as well as some of the considerations that have to be made in order to obtain accurate PSF-fitting stellar photometry with WFPC2 data. Tests of HSTphot's internal reliability are made using multiple observations of the same field, and tests of external reliability are made by comparing with DoPHOT reductions of the same data. Subject headz'ngs: techniques: photometric

Dolphin, Andrew E.

2000-01-01

119

Hyper: Hybrid photometry and extraction routine  

NASA Astrophysics Data System (ADS)

We present a new hybrid photometry and extraction routine called Hyper. It is designed to do compact source photometry, allowing for varying spatial resolution and sensitivity in multi-wavelength surveys. Hyper combines multi-Gaussian fitting with aperture photometry to provide reliable photometry in regions with variable backgrounds and in crowded fields. The background is evaluated and removed locally for each source using polynomial fits of various orders. Source deblending is done through simultaneous multi-Gaussian fitting of the main source and its companion(s), followed by the subtraction of the companion(s). Hyper also allows simultaneous multi-wavelength photometry by setting a fixed aperture size independent of the map resolution and by evaluating the source flux within the same region of the sky at multiple wavelengths at the same time. This new code has been initially designed for precise aperture photometry in complex fields such as the Galactic plane observed in the far infrared (FIR) by the Herschel infrared survey of the Galactic plane (Hi-GAL). Hyper has been tested on both simulated and real Herschel fields to quantify the quality of the source identification and photometry. The code is highly modular and fully parameterisable, therefore it can be easily adapted to different experiments. Comparison of the Hyper photometry with the catalogued sources in the Bolocam Galactic Plane Survey (BGPS), the 1.1 mm survey of the Galactic plane carried out with the Caltech Submillimeter Observatory, demonstrates the versatility of Hyper on different datasets. It is fast and light in its memory, and it is freely available to the scientific community.

Traficante, A.; Fuller, G. A.; Pineda, J. E.; Pezzuto, S.

2015-02-01

120

WFPC2 Stellar Photometry with HSTphot  

Microsoft Academic Search

HSTphot, a photometry package designed to handle the undersampled PSFs found\\u000ain WFPC2 images, is introduced and described, as well as some of the\\u000aconsiderations that have to be made in order to obtain accurate PSF-fitting\\u000astellar photometry with WFPC2 data. Tests of HSTphot's internal reliability are\\u000amade using multiple observations of the same field, and tests of external\\u000areliability

2000-01-01

121

2060 Chiron - CCD and electronographic photometry  

Microsoft Academic Search

R-band observations conducted for 2060 Chiron using CCD photometry in November-December 1986 and March 1988 are discussed. While the 1986 observations exhibit neither periodic nor nonperiodic brightness changes ascribable to comet-like activity, the 1988 observations show an 0.6 + or - 0.1 mag brightening that confirms the Tholen et al. (1988) findings and is consistent with the 1978 electronographic photometry

Schelte J. Bus; Edward Bowell; Alan W. Harris; Anthony V. Hewitt

1989-01-01

122

Meteor44 Video Meteor Photometry  

NASA Technical Reports Server (NTRS)

Meteor44 is a software system developed at MSFC for the calibration and analysis of video meteor data. The dynamic range of the (8bit) video data is extended by approximately 4 magnitudes for both meteors and stellar images using saturation compensation. Camera and lens specific saturation compensation coefficients are derived from artificial variable star laboratory measurements. Saturation compensation significantly increases the number of meteors with measured intensity and improves the estimation of meteoroid mass distribution. Astrometry is automated to determine each image's plate coefficient using appropriate star catalogs. The images are simultaneously intensity calibrated from the contained stars to determine the photon sensitivity and the saturation level referenced above the atmosphere. The camera s spectral response is used to compensate for stellar color index and typical meteor spectra in order to report meteor light curves in traditional visual magnitude units. Recent efforts include improved camera calibration procedures, long focal length 'streak' meteor photometry and two-station track determination. Meteor44 has been used to analyze data from the 2001, 2002 and 2003 MSFC Leonid observational campaigns as well as several lesser showers. The software is interactive and can be demonstrated using data from recent Leonid campaigns.

Swift, Wesley R.; Suggs, Robert M.; Cooke, William J.

2004-01-01

123

Changes in soil DOC affect reconstructed history and projected future trends in surface water acidification  

NASA Astrophysics Data System (ADS)

Over the last two decades there has been growing evidence of widespread increasing concentrations of dissolved organic carbon (DOC) in surface waters in several regions in Europe and North America. Two main drivers have been proposed to explain this observation: climate change entailing changed humidity and temperature which alter rates of microbial processes and reductions in acid deposition which lead to decreased concentrations of strong acid anions and alter rates of decomposition and solubility of organic matter in soil. The question of historical DOC concentrations is therefore important for quantifying present-day acidification and possible future recovery of the surface waters. Due to the paucity of historical data, estimates of pre-acidification chemical and biological status usually come from modeling applications. Lack of process-understanding and of consensus upon what has been driving the observed DOC trends makes modeling uncertain and model outcomes are subject to controversy. Here we apply the MAGIC model to the long-term observed soil and streamwater chemistry data from an anthropogenically acidified small Lysina catchment, Czech Republic, to illustrate the importance of choice of source of DOC during recovery from acidification. The annual mean streamwater DOC concentration increased from 15.6-16.9 mg L-1 (1993-1994) to 21.8-24.5 mg L-1 in 2010-2011, an average annual increase of 0.6 mg L-1 year-1 (p<0.001). Even stronger DOC trends were observed for soilwater draining the organic soil horizons. Mean annual DOC increased from 41-42 mg L-1 in 1993-1994 to 67-74 mg L-1 in 2010-2011 below the organic horizon (at 5 cm depth below the surface), an annual increase of 2.7 mg L-1 year-1 (p<0.001). At 15 cm depth below the surface, in the uppermost mineral horizon (E), the DOC concentrations increased from 31-34 mg L-1 to 68-73 mg L-1, an annual increase of 1.9 mg L-1 year-1 (p<0.005) Pre-industrial (1850´s) and future (2060) streamwater chemistry was estimated using the MAGIC model for three different dissolved organic carbon (DOC) levels and sources. The highest pH = 5.7 for 1850´s as well as for 2060 (pH = 4.4) was simulated given the assumption that streamwater DOC concentration was constant at the 1993 level. A scenario accounting for an increase of DOC as an inverse function of ionic strength (it has declined as a result of decreasing acidic deposition) of soilwater and streamwater resulted in much lower pre-industrial pH=4.9 and future recovery to pH=4.1 if only stream riparian zone was taken as a DOC source. If upland soilwater (where significant DOC increase was observed at -5 cm and -15 cm) was also included, DOC was partly neutralized by base cations within the soil and pre-industrial pH=5.3 and future pH = 4.2 were estimated. The observed DOC riverine flux was 2 - 4 times higher than the potential carbon production of the riparian zone. Thus modelling pre-industrial pH based on the assumption that stream DOC changes are solely attributable to changes in the riparian zone appears likely to result in a substantial under-estimate of pre-industrial and future steamwater pH.

Hruška, Jakub; Krám, Pavel; Moldan, Filip; Oulehle, Filip; Evans, Christopher D.; Wright, Richard F.; Cosby, Bernard J.

2013-04-01

124

Superoxide dismutase activity in Pseudomonas putida affects utilization of sugars and growth on root surfaces.  

PubMed

To investigate the role of superoxide dismutases (SOD) in root colonization and oxidative stress, mutants of Pseudomonas putida lacking manganese-superoxide dismutase (MnSOD) (sodA), iron-superoxide dismutase (FeSOD) (sodB), or both were generated. The sodA sodB mutant did not grow on components washed from bean root surfaces or glucose in minimal medium. The sodB and sodA sodB mutants were more sensitive than wild type to oxidative stress generated within the cell by paraquat treatment. In single inoculation of SOD mutants on bean, only the sodA sodB double mutant was impaired in growth on root surfaces. In mixed inoculations with wild type, populations of the sodA mutant were equal to those of the wild type, but levels of the sodB mutant and, to a great extent, the sodA sodB mutant, were reduced. Confocal microscopy of young bean roots inoculated with green fluorescent protein-tagged cells showed that wild type and SOD single mutants colonized well predominantly at the root tip but that the sodA sodB double mutant grew poorly at the tip. Our results indicate that FeSOD in P. putida is more important than MnSOD in aerobic metabolism and oxidative stress. Inhibition of key metabolic enzymes by increased levels of superoxide anion may cause the impaired growth of SOD mutants in vitro and in planta. PMID:10742227

Kim, Y C; Miller, C D; Anderson, A J

2000-04-01

125

Polarimetric Retrievals of Surface and Aerosol Properties in the Region Affected by the Deepwater Horizon Oil Spill  

NASA Astrophysics Data System (ADS)

In July 2010, the Research Scanning Polarimeter (RSP) effectuated two flights in two consecutive days over the region affected by the oil spill of the Deepwater Horizon offshore platform. Integrated on the NASA Langley B-200 aircraft, the instrument is deployed together with the High Spectral Resolution Lidar (HSRL), which provides information on the distribution of the aerosol layers beneath the aircraft including an accurate estimate of aerosol optical depth. We present a sensitivity study to illustrate the merits of polarization measurements in detecting variations of ocean surface properties linked to the presence of an oil slick. In particular, the Degree of Linear Polarization (DoLP) in the glint region does not depend on the surface roughness, while is severely affected by variations in the refractive index of the ocean surface. Exploiting the RSP channel at 2250nm, where virtually all the signal is generated by the Fresnel reflection at the surface, the DoLP at any angle well into the glint region can therefore be used to detect alterations in the ocean surface. More specifically, the glint profile at this wavelength is fitted to the Cox-Munk model with a routine which can optimally estimate wind speed and direction, while taking into account aircraft attitude variations in determining the viewing geometry. The surveyed area also presents a complex mix of aerosol types. At least one major urban layer originating in the US Southeast mixes in the central portion of the flight trajectory with smoke caused by controlled burns around the damaged platform. The constrain on surface reflectance provided by the SWIR RSP channel, together with the aerosol optical depth provided by the HSRL, are used in Radiative Transfer computations to model the channels at shorter wavelengths and retrieve aerosol descriptive parameters such as aerosol size distribution and refractive index. Finally, the presence of smoke is ground for a discussion on the possibility to infer aerosol absorption. In this respect, RSP retrieval can be aided by the HSRL unique capability of measuring aerosol extinction and backscatter independently.

Ottaviani, M.; Cairns, B.; Chowdhary, J.; Knobelspiesse, K. D.; Ferrare, R. A.; Hostetler, C. A.; Hair, J. W.; Rogers, R.; Obland, M. D.; Zhai, P.; Hu, Y.

2010-12-01

126

Enteric YaiW Is a Surface-Exposed Outer Membrane Lipoprotein That Affects Sensitivity to an Antimicrobial Peptide  

PubMed Central

yaiW is a previously uncharacterized gene found in enteric bacteria that is of particular interest because it is located adjacent to the sbmA gene, whose bacA ortholog is required for Sinorhizobium meliloti symbiosis and Brucella abortus pathogenesis. We show that yaiW is cotranscribed with sbmA in Escherichia coli and Salmonella enterica serovar Typhi and Typhimurium strains. We present evidence that the YaiW is a palmitate-modified surface exposed outer membrane lipoprotein. Since BacA function affects the very-long-chain fatty acid (VLCFA) modification of S. meliloti and B. abortus lipid A, we tested whether SbmA function might affect either the fatty acid modification of the YaiW lipoprotein or the fatty acid modification of enteric lipid A but found that it did not. Interestingly, we did observe that E. coli SbmA suppresses deficiencies in the VLCFA modification of the lipopolysaccharide of an S. meliloti bacA mutant despite the absence of VLCFA in E. coli. Finally, we found that both YaiW and SbmA positively affect the uptake of proline-rich Bac7 peptides, suggesting a possible connection between their cellular functions. PMID:24214946

Arnold, Markus F. F.; Caro-Hernandez, Paola; Tan, Karen; Runti, Giulia; Wehmeier, Silvia; Scocchi, Marco; Doerrler, William T.; Ferguson, Gail P.

2014-01-01

127

How does the spaceborne radar blind zone affect derived surface snowfall statistics in polar regions?  

NASA Astrophysics Data System (ADS)

Global statistics of snowfall are currently only available from the CloudSat satellite. But CloudSat cannot provide observations of clouds and precipitation within the so-called blind zone, which is caused by ground-clutter contamination of the CloudSat radar and covers the last 1200 m above land/ice surface. In this study, the impact of the blind zone of CloudSat on derived snowfall statistics in polar regions is investigated by analyzing three 12 month data sets recorded by ground-based Micro Rain Radar (MRR) at the Belgian Princess Elisabeth station in East Antarctica and at Ny-Ålesund and Longyearbyen in Svalbard, Norway. MRR radar reflectivity profiles are investigated in respect to vertical variability in the frequency distribution, changes in the number of observed snow events, and impacts on total precipitation. Results show that the blind zone leads to reflectivity being underestimated by up to 1 dB, the number of events being altered by ±5% and the precipitation amount being underestimated by 9 to 11 percentage points. Besides investigating a blind zone of 1200 m, the impacts of a reduced blind zone of 600 m are also analyzed. This analysis will help in assessing future missions with a smaller blind zone. The reduced blind zone leads to improved representation of mean reflectivity but does not improve the bias in event numbers and precipitation amount.

Maahn, Maximilian; Burgard, Clara; Crewell, Susanne; Gorodetskaya, Irina V.; Kneifel, Stefan; Lhermitte, Stef; Van Tricht, Kristof; Lipzig, Nicole P. M.

2014-12-01

128

Sea surface temperature fronts affect distribution of Pacific saury (Cololabis saira) in the Northwestern Pacific Ocean  

NASA Astrophysics Data System (ADS)

Pacific saury (Cololabis saira) is an important fisheries resource and commercial species of Taiwanese deep-sea saury stick-held dip net fishery in the Northwestern Pacific Ocean. In this study, the logbook data of a 3-year (2006-2008) Taiwanese Pacific saury fishery and corresponding satellite-derived MODIS sea surface temperature (SST) data were analyzed to detect SST fronts and examine their influence on the spatio-temporal distribution of Pacific saury. The fronts were identified by the Cayula-Cornillon single-image edge detection algorithm. The results show that low frequency of SST fronts is associated with lower CPUEs during the early fishing season (June-August), while high frequency of SST fronts is associated with higher CPUEs during the peak fishing season. When fishing locations of Pacific saury are close to the SST fronts, higher CPUEs are observed. Results of this study provide a better understanding of how SST fronts influence distribution of Pacific saury and improve the basis of fishing ground forecasting.

Tseng, Chen-Te; Sun, Chi-Lu; Belkin, Igor M.; Yeh, Su-Zan; Kuo, Chin-Lau; Liu, Don-Chung

2014-09-01

129

Mg2+ binds to the surface of thymidylate synthase and affects hydride transfer at the interior active site  

PubMed Central

Thymidylate synthase (TSase) produces the sole intracellular de novo source of thymidine (i.e. the DNA base T) and thus is a common target for antibiotic and anticancer drugs. Mg2+ has been reported to affect TSase activity, but the mechanism of this interaction has not been investigated. Here we show that Mg2+ binds to the surface of Escherichia coli TSase and affects the kinetics of hydride transfer at the interior active site (16 Å away). Examination of the crystal structures identifies a Mg2+ near the glutamyl moiety of the folate cofactor, providing the first structural evidence for Mg2+ binding to TSase. The kinetics and NMR relaxation experiments suggest that the weak binding of Mg2+ to the protein surface stabilizes the closed conformation of the ternary enzyme complex and reduces the entropy of activation on the hydride transfer step. Mg2+ accelerates the hydride transfer by ca. 7-fold but does not affect the magnitude or temperature-dependence of the intrinsic kinetic isotope effect. These results suggest that Mg2+ facilitates the protein motions that bring the hydride donor and acceptor together, but it does not change the tunneling ready state of the hydride transfer. These findings highlight how variations in cellular Mg2+ concentration can modulate enzyme activity through long-range interactions in the protein, rather than binding at the active site. The interaction of Mg2+ with the glutamyl-tail of the folate cofactor and nonconserved residues of bacterial TSase may assist in designing antifolates with poly-glutamyl substitutes as species-specific antibiotic drugs. PMID:23611499

Wang, Zhen; Sapienza, Paul J.; Abeysinghe, Thelma; Luzum, Calvin; Lee, Andrew L.; Finer-Moore, Janet S.; Stroud, Robert M.; Kohen, Amnon

2013-01-01

130

Optical properties of boreal forest fire smoke derived from Sun photometry  

Microsoft Academic Search

Aerosol optical properties derived from Sun photometry were investigated in terms of climatological trends at two Sun photometer sites significantly affected by western Canadian boreal forest fire smoke and in terms of a 2-week series of smoke events observed at stations near and distant from boreal forest fires. Aerosol optical depth (taua) statistics for Waskesiu, Saskatchewan, and Thompson, Manitoba, were

N. T. O'Neill; T. F. Eck; B. N. Holben; A. Smirnov; A. Royer; Z. Li

2002-01-01

131

NAAP Variable Star Photometry 1/12 Variable Star Photometry Student Guide  

E-print Network

Name: NAAP ­ Variable Star Photometry 1/12 Variable Star Photometry ­ Student Guide Background of Variable Stars and Properties of CCDs. Question 1: The light variation from a variable star is shown in the figure to the right. a) Identify the type of variable star and explain your criteria for classifying

Farritor, Shane

132

Calibration of the MACHO Photometry Database  

NASA Astrophysics Data System (ADS)

The MACHO Project is a microlensing survey that monitors the brightnesses of ~60 million stars in the Large Magellanic Cloud (LMC), Small Magellanic Cloud, and Galactic bulge. Our database presently contains about 80 billion photometric measurements, a significant fraction of all astronomical photometry. We describe the calibration of MACHO two-color photometry and transformation to the standard Kron-Cousins V and R system. Calibrated MACHO photometry may be properly compared with all other observations on the Kron-Cousins standard system, enhancing the astrophysical value of these data. For ~9 million stars in the LMC bar, independent photometric measurements of ~20,000 stars with V<~18 mag in field-overlap regions demonstrate an internal precision ?V=0.021, ?R=0.019, ?V-R=0.028 mag. The accuracy of the zero point in this calibration is estimated to be +/-0.035 mag for stars with colors in the range -0.1 magphotometry with published photometric sequences and new Hubble Space Telescope observations shows agreement. The current calibration zero-point uncertainty for the remainder of the MACHO photometry database is estimated to be +/-0.10 mag in V or R and +/-0.04 mag in V-R. We describe the first application of calibrated MACHO data: the construction of a color-magnitude diagram used to calculate our experimental sensitivity for detecting microlensing in the LMC.

Alcock, C.; Allsman, R. A.; Alves, D. R.; Axelrod, T. S.; Becker, A. C.; Bennett, D. P.; Cook, K. H.; Drake, A. J.; Freeman, K. C.; Geha, M.; Griest, K.; Lehner, M. J.; Marshall, S. L.; Minniti, D.; Peterson, B. A.; Popowski, P.; Pratt, M. R.; Nelson, C. A.; Quinn, P. J.; Stubbs, C. W.; Sutherland, W.; Tomaney, A. B.; Vandehei, T.; Welch, D. L.; MACHO Collaboration

1999-12-01

133

Longtime monitoring of groundwater levels and matric potentials in organic and inorganic soils affected by surface drainage and groundwater extraction  

NASA Astrophysics Data System (ADS)

Drainage of organic soils leads to severe degradation of the soil matrix due to shrinkage, oxidation and development of hydrophobicity. Also, grassland vegetation on cultivated peatland soils is adapted to water supply through capillary rise from the groundwater to guarantee good yields. Monitoring of groundwater levels and soil matric potentials was performed in a period of ten years (2003-2013) at six investigation sites in a plain tract surrounded by Saalean deposits in south-west Schleswig-Holstein, Germany. The area is under agricultural use; all monitoring sites are under grassland. The groundwater situation in the area has been strongly affected by surface drainage (since 1969) and groundwater extraction for industrial and private utilization (since 1977). Soil physical measurements on soil samples taken from six soil profiles in the investigation area (2003) showed an advanced degradation of the organic soil horizons as a result of the dewatering. Furthermore, in 2003 drainage and groundwater extraction resulted in a situation, where water supply in the root zone via capillary rise from the groundwater was no longer guaranteed on some of the investigation sites, leading to yield depressions in dry periods as the vegetation was dependent on precipitation events for water supply. In 2006 new regulations of the groundwater extraction lead to a continuously rise of the groundwater level, indicating an interaction between the surface aquifer and the deep aquifer where the groundwater was extracted, as the surface drainage management remained unchanged. Correlations between the extraction rate of the groundwater wells in the investigation area and the groundwater level in the surface aquifer were found.

Zimmermann, Iris; Fleige, Heiner; Horn, Rainer

2014-05-01

134

Gaia photometry for white dwarfs  

NASA Astrophysics Data System (ADS)

Context. White dwarfs can be used to study the structure and evolution of the Galaxy by analysing their luminosity function and initial mass function. Among them, the very cool white dwarfs provide the information for the early ages of each population. Because white dwarfs are intrinsically faint only the nearby (~ 20 pc) sample is reasonably complete. The Gaia space mission will drastically increase the sample of known white dwarfs through its 5-6 years survey of the whole sky up to magnitude V = 20-25. Aims: We provide a characterisation of Gaia photometry for white dwarfs to better prepare for the analysis of the scientific output of the mission. Transformations between some of the most common photometric systems and Gaia passbands are derived. We also give estimates of the number of white dwarfs of the different galactic populations that will be observed. Methods: Using synthetic spectral energy distributions and the most recent Gaia transmission curves, we computed colours of three different types of white dwarfs (pure hydrogen, pure helium, and mixed composition with H/He = 0.1). With these colours we derived transformations to other common photometric systems (Johnson-Cousins, Sloan Digital Sky Survey, and 2MASS). We also present numbers of white dwarfs predicted to be observed by Gaia. Results: We provide relationships and colour-colour diagrams among different photometric systems to allow the prediction and/or study of the Gaia white dwarf colours. We also include estimates of the number of sources expected in every galactic population and with a maximum parallax error. Gaia will increase the sample of known white dwarfs tenfold to about 200 000. Gaia will be able to observe thousands of very cool white dwarfs for the first time, which will greatly improve our understanding of these stars and early phases of star formation in our Galaxy. Tables 6 and 7 are available in electronic form at http://www.aanda.orgFull Tables 3-5 are available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/565/A11

Carrasco, J. M.; Catalán, S.; Jordi, C.; Tremblay, P.-E.; Napiwotzki, R.; Luri, X.; Robin, A. C.; Kowalski, P. M.

2014-05-01

135

Simultaneous multicolor photometry of fast-moving objects using the 1-meter telescope at Xinglong Observatory  

NASA Astrophysics Data System (ADS)

Simultaneous multicolor photometry of fast-moving objects is discussed in this paper. In conventional astronomical photometry, the accuracy of flux and color indices of fast-moving objects is affected by the variations of the targets and weather conditions in space and time domains. We optimize related techniques and methods of observation and data reduction, including image calibration, background fitting, targets detection and location, isophotal photometry, and flux calibration by using background stars from different fields. We consider that simultaneous multicolor data acquisition and differential flux calibration are critical for improving photometric accuracy of fast-moving objects. Our results show the photometric accuracy is better than 5% based on the observations carried out by a 1-meter telescope under ordinary, non-photometric conditions.

Mao, YongNa; Lu, XiaoMeng; Wang, JianFeng

2014-03-01

136

Detection of Terrestrial Planets Using Transit Photometry  

NASA Technical Reports Server (NTRS)

Transit photometry detection of planets offers many advantages: an ability to detect terrestrial size planets, direct determination of the planet's size, applicability to all main-sequence stars, and a differential brightness change of the periodic signature being independent of stellar distance or planetary orbital semi-major axis. Ground and space based photometry have already been successful in detecting transits of the giant planet HD209458b. However, photometry 100 times better is required to detect terrestrial planets. We present results of laboratory measurements of an end-to-end photometric system incorporating all of the important confounding noise features of both the sky and a space based photometer including spacecraft jitter. In addition to demonstrating an instrumental noise of less than 10 ppm (an Earth transit of a solar-like star is 80 ppm), the brightnesses of individual stars were dimmed to simulate Earth-size transit signals. These 'transits' were reliably detected as part of the tests.

Koch, David; Witteborn, Fred; Jenkins, Jon; Dunham, Edward; Boruci, William; DeVincenzi, Donald (Technical Monitor)

2001-01-01

137

Retention and rainfastness of mancozeb as affected by physicochemical characteristics of adaxial apple leaf surface after enhanced UV-B radiation  

Microsoft Academic Search

It is not clear so far whether alteration of leaf micromorphology and surface wax chemistry due to the impact of environmental factors, such as UV-B radiation, affects retention and rainfastness of applied pesticide solutions. In this study; UV-B treated and untreated adaxial leaf surfaces of apple seedlings (Malus domestica Borkh.) were characterized in terms of chemical composition, micromorphological fine structure,

Katja Bringe; Mauricio Hunsche; Michaela Schmitz-Eiberger; Georg Noga

2007-01-01

138

A genome-wide search for quantitative trait loci affecting the cortical surface area and thickness of Heschl's gyrus.  

PubMed

Heschl's gyrus (HG) is a core region of the auditory cortex whose morphology is highly variable across individuals. This variability has been linked to sound perception ability in both speech and music domains. Previous studies show that variations in morphological features of HG, such as cortical surface area and thickness, are heritable. To identify genetic variants that affect HG morphology, we conducted a genome-wide association scan (GWAS) meta-analysis in 3054 healthy individuals using HG surface area and thickness as quantitative traits. None of the single nucleotide polymorphisms (SNPs) showed association P values that would survive correction for multiple testing over the genome. The most significant association was found between right HG area and SNP rs72932726 close to gene DCBLD2 (3q12.1; P=2.77 × 10(-7) ). This SNP was also associated with other regions involved in speech processing. The SNP rs333332 within gene KALRN (3q21.2; P=2.27 × 10(-6) ) and rs143000161 near gene COBLL1 (2q24.3; P=2.40 × 10(-6) ) were associated with the area and thickness of left HG, respectively. Both genes are involved in the development of the nervous system. The SNP rs7062395 close to the X-linked deafness gene POU3F4 was associated with right HG thickness (Xq21.1; P=2.38 × 10(-6) ). This is the first molecular genetic analysis of variability in HG morphology. PMID:25130324

Cai, D-C; Fonteijn, H; Guadalupe, T; Zwiers, M; Wittfeld, K; Teumer, A; Hoogman, M; Arias-Vásquez, A; Yang, Y; Buitelaar, J; Fernández, G; Brunner, H G; van Bokhoven, H; Franke, B; Hegenscheid, K; Homuth, G; Fisher, S E; Grabe, H J; Francks, C; Hagoort, P

2014-09-01

139

CLEA: Photoelectric Photometry of the Pleiades  

NSDL National Science Digital Library

This lab is designed to familiarize students with the technique of photoelectric filter photometry and counting statistics. The software for this exercise puts students in control of a computer-controlled telescope with sidereal tracking. It illustrates the use of equatorial coordinates for finding stars in a cluster and introduces the use of H-R diagrams for analyzing the age and distance of clusters. A student guide supplied with the software describes how to use B and V photometry of cluster members to plot an H-R diagram of the Pleiades and to determine its distance. This is part of a larger collection of simulations, Project CLEA.

Marschall, Laurence; Snyder, Glenn; Cooper, P. R.; Hayden, Michael; Good, Rhonda

2008-12-15

140

NIST Photometry Short Course September 27-30, 2011  

E-print Network

NIST Photometry Short Course September 27-30, 2011 100 Bureau Drive, Gaithersburg, MD 20899 Bldg.00 ) Registrant Information gfedc gfedc Page 1 of 3NIST Conference Registration 6/29/2011file://Z:\\My Documents\\FORMS\\photometry

Perkins, Richard A.

141

Extrasolar planet transit photometry at Wallace Astrophysical Observatory  

E-print Network

Extrasolar planet transit photometry is a relatively new astronomical technique developed over the past decade. Transit photometry is the measurement of a star's brightness as an orbiting planet passes in front of the star ...

Fong, Wen-fai

2008-01-01

142

The Aperture Photometry: a Software Package for IBM Personal Computers  

NASA Astrophysics Data System (ADS)

A software package, AFO, for interactive aperture photometry is presented. Observational data of the open cluster M 67 are used to test the package. The results of our photometry are compared with those obtained by the IRAF/Apphot package. Various routines of AFO and the accuracy of the photometry are discussed. A new method of the aperture photometry based on growth-curve analysis is introduced.

Bridzius, A.; Vansevicius, V.

1997-12-01

143

Instrument Science Report ACS 2006-01 PSFs, Photometry,  

E-print Network

Instrument Science Report ACS 2006-01 PSFs, Photometry, and Astrometry for the ACS/WFC Jay Anderson is to be interpolated for each star. Fitting these PSFs to star images gives photometry and astrometry with accuracies hurting photometry. The following sections present our modeling of the F606W PSF, and also provide PSFs

Sirianni, Marco

144

WFPC2 Photometry from Subtraction of Observed PSFs  

E-print Network

1 WFPC2 Photometry from Subtraction of Observed PSFs J. Surdej1,2 , S. Baggett3 , M. Remy1 , M of PSF subtrac- tion tests have been performed and the resulting photometry analyzed. We find that using or planets) but also provides a means of deriving accurate photometry of the primary objects

Sirianni, Marco

145

Systematic photometry of XUV solar images  

Microsoft Academic Search

Units and methods have been devised to express the photometry of solar XUV images. The source and limb-brightened fluxes are given in terms of the sun's quiet central intensity. Measurements made on this system can be meaningfully compared with solar data and with theoretical predictions. Calculations have been made of the XUV distribution for optically thin solar models and results

C. W. Allen

1969-01-01

146

Diffraction Losses in Radiometry and Photometry  

Microsoft Academic Search

The precision of radiometry and photometry is reaching a stage, in standardizing laboratories at least, where greater attention should be paid to losses of flux by diffraction. Otherwise errors of up to 0.5% or more may occur. This article reviews from the radiometric point of view diffraction losses at circular apertures, for both the Fraunhofer and Fresnel conditions and for

W R Blevin

1970-01-01

147

Near-Field Photometry: A New Approach  

Microsoft Academic Search

This paper presents a new approach to near-field photometry and describes a novel nearfieldgoniophotometer and illuminance calculation method. The approach is based onhelios, which is a rationalization of the luminance concept for volume sources. Thegoniophotometer measures the three-dimensional vector field of light surrounding aluminaire rather than any of its intrinsic properties. The calculation method can predictthe illuminance at any point

Ian Ashdown

1992-01-01

148

International Studies of Hazardous Groundwater/Surface Water Exchange in the Volcanic Eruption and Tsunami Affected Areas of Kamchatka  

NASA Astrophysics Data System (ADS)

During the US-Russia Geohazards Workshop held July 17-19, 2012 in Moscow, Russia the international research effort was asked to identify cooperative actions for disaster risk reduction, focusing on extreme geophysical events. As a part of this recommendation the PIRE project was developed to understand, quantify, forecast and protect the coastal zone aquifers and inland water resources of Kamchatka (Russia) and its ecosystems affected by the November 4, 1952 Kamchatka tsunami (Khalatyrka Beach near Petropavlovsk-Kamchatskiy) and the January 2, 1996 Karymskiy volcano eruption and the lake tsunami. This project brings together teams from U.S. universities and research institutions located in Russia. The research consortium was briefed on recent technical developments and will utilize samples secured via major international volcanic and tsunami programs for the purpose of advancing the study of submarine groundwater discharge (SGD) in the volcanic eruption and tsunami affected coastal areas and inland lakes of Kamchatka. We plan to accomplish this project by developing and applying the next generation of field sampling, remote sensing, laboratory techniques and mathematical tools to study groundwater-surface water interaction processes and SGD. We will develop a field and modeling approach to define SGD environment, key controls, and influence of volcano eruption and tsunami, which will provide a framework for making recommendations to combat contamination. This is valuable for politicians, water resource managers and decision-makers and for the volcano eruption and tsunami affected region water supply and water quality of Kamchatka. Data mining and results of our field work will be compiled for spatial modeling by Geo-Information System (GIS) using 3-D Earth Systems Visualization Lab. The field and model results will be communicated to interested stakeholders via an interactive web site. This will allow computation of SGD spatial patterns. In addition, thanks to the conceptual integrated approach, the mathematical tool will be transportable to other regions affected by volcanic eruption and tsunami. We will involve students in the work, incorporate the results into our teaching portfolio and work closely with the IUGG GeoRisk Commission and AGU Natural Hazards Focus Group to communicate our findings to the broader public, specifically local communities that will be most impacted. Under the PIRE education component, a cohort of U.S. and Russian post-doctoral researchers and students will receive training and contribute to the overall natural hazards SGD science agenda in cooperation with senior U.S. researchers and leading investigators from the Russian institutions. Overall, the extensive team of researchers, students and institutions is poised to deliver an innovative and broad spectrum of science associated with the study of SGD in the volcanic eruption and tsunami affected areas, in a way not possible to achieve in isolation.

Kontar, Y. A.; Gusiakov, V. K.; Izbekov, P. E.; Gordeev, E.; Titov, V. V.; Verstraeten, I. M.; Pinegina, T. K.; Tsadikovsky, E. I.; Heilweil, V. M.; Gingerich, S. B.

2012-12-01

149

How do Atmospheres Affect Planetary Temperatures? Activity C Can we Model an Atmosphere's Effect Upon a Planet's Surface Temperature?  

NSDL National Science Digital Library

In this activity, students simulate the interaction of variables, including carbon dioxide, in a radiation balance exercise using a spreadsheet-based radiation balance model. Through a series of experiments, students attempt to mimic the surface temperatures of Earth, Mercury, Venus and Mars, and account for the influence of greenhouse gases in atmospheric temperatures. The activity supports inquiry into the real-world problem of contemporary climate change. Student-collected data is needed from activity A in the same module, "How do atmospheres interact with solar energy?" to complete this activity. Included in the resource are several student data sheets and a teacher's guide. This activity is part of module 4, "How do Atmospheres Affect Planetary Temperatures?" in Earth Climate Course: What Determines a Planet's Climate? The course aims to help students to develop an understanding of our environment as a system of human and natural processes that result in changes that occur over various space and time scales.

150

Does the temperature of beverages affect the surface roughness, hardness, and color stability of a composite resin?  

PubMed Central

Objective: To investigate the effect of beverages’ temperature on the surface roughness, hardness, and color stability of a composite resin. Materials and Methods: Fifty specimens of the Filtek Z250 composite (3M ESPE, Dental Products, St.Paul, MN, USA) were prepared and initial roughness, microhardness, and color were measured. Then the specimens were randomly divided into five groups of 10 specimens each: Coffee at 70°C, coffee at 37°C, cola at 10°C, cola at 37°C, and artificial saliva (control). After the samples were subjected to 15 min × 3 cycles per day of exposure to the solutions for 30 days, the final measurements were recorded. Results: After immersion in beverages, the artificial saliva group showed hardness values higher than those of the other groups (P < 0.001) and the microhardness values were significantly different from the initial values in all groups except for the control group. Both cola groups showed roughness values higher than the baseline values (P < 0.05), while the other groups showed values similar to the baseline measurements. When ?E measurements were examined, the 70°C coffee group showed the highest color change among all the groups (P < 0.05). Conclusion: High-temperature solutions caused alterations in certain properties of composites, such as increased color change, although they did not affect the hardness or roughness of the composite resin material tested. PMID:24883021

Tuncer, Duygu; Karaman, Emel; Firat, Esra

2013-01-01

151

The structure of the Galaxy from stellar photometry  

NASA Astrophysics Data System (ADS)

We have established deep CCD photometry in V and I bands of four fields along the outer galactic disk. These fields are selected on the basis of surface photometries of the Milky Way in U,B,V,R (Kimeswenger et al., 1993, A&AS, 97, 517; Hoffmann et al., 1998, A&AS, 128, 417). The observation has been conducted in Februar 1997 with the Danish 1.5 at ESO, La Silla, Chile. The modelling of the galaxy is done with a code already described by Ng et al. (1995, A&A, 295, 655) and Bertelli et al. (1995, A&A, 301 381), where starting from a set of stellar isochrones of different ages and metallicity, Monte Carlo simulations are calculated to determine the synthetic stars along the line of sight. The resulting colour-magnitude-diagrams (CMDs) and luminosity functions have been compared with the observed ones to derive the ages and spatial distribution of all involved components. The reddening along the line of sight is derived and the results have been compared with the maps of Schlegel et al. (1998, APJ, 500, 525) and Mendez & van Altena (1998, A&A, 330, 910). We here present the measured and synthetic CMDs and discuss the resulting parameters for the galactic structure and the star formation history of the disk. Two stellar distributions (sech^2 and double exponential) for the thin and thick disk components are tested. The scale height and scale length of the thin disk are derived.

Schmidtobreick, L.; Vallenari, A.; Bertelli, G.

152

Galileo Photometry of Asteroid 951 Gaspra  

USGS Publications Warehouse

Galileo images of Gaspra make it possible for the first time to determine a main-belt asteroid's photometric properties accurately by providing surface-resolved coverage over a wide range of incidence and emission angles and by extending the phase angle coverage to phases not observable from Earth. We combine Earth-based telescopic photometry over phase angles 2?? ??? ?? ??? 25?? with Galileo whole-disk and disk-resolved data at 33?? ??? ?? ??? 51?? to derive average global photometric properties in terms of Hapke's photometric model. The microscopic texture and particle phase-function behavior of Gaspra's surface are remarkably like those of other airless rocky bodies such as the Moon. The macroscopic surface roughness parameter, ??? = 29??, is slightly larger than that reported for typical lunar materials. The particle single scattering albedo, ???0 = 0.36 ?? 0.07, is significantly larger than for lunar materials, and the opposition surge amplitude, B0 = 1.63 ?? 0.07, is correspondingly smaller. We determine a visual geometric albedo pv = 0.22 ?? 0.06 for Gaspra, in close agreement with pv = 0.22 ?? 0.03 estimated from Earth-based observations. Gaspra's phase integral is 0.47, and the bolometric Bond albedo is estimated to be 0.12 ?? 0.03. An albedo map derived by correcting Galileo images with our average global photometric function reveals subdued albedo contrasts of ??10% or less over Gaspra's northern hemisphere. Several independent classification algorithms confirm the subtle spectral heterogeneity reported earlier (S. Mottola, M. DiMartino, M. Gonano-Beurer, H. Hoffman, and G. Neukum, 1993, Asteroids, Comets, Meteors, pp. 421-424; M. J. S. Belton et al., 1992, Science 257, 1647-1652). Whole-disk colors (0.41 ??? ?? ??? 0.99 ??m) vary systematically with longitude by about ??5%, but color differences as large as 30% occur locally. Colors vary continuously between end-member materials whose areal distribution correlates with regional topography. Infrared: violet (0.99:0.41-??m) color ratios on Gaspra are strongly correlated with local elevation, being largest at lower elevations and smaller at higher elevations. No correlation was detected between elevation and the green:violet (0.56:0.41-??m) color ratio. Bright materials with a strong 1-??m absorption occur primarily in association with craters along ridges, while darker materials with 30% weaker 1-??m signatures occur downslope. The variations of color and albedo cannot be easily explained by grain-size effects alone or by differences in photometric geometry. The trends observed are consistent with those revealed by laboratory studies of the effects of comminution, glass formation, and segregation of metal from silicate components in chondritic meteorites and also in some silicate mixtures. The relative importance of these various processes on Gaspra remains to be determined. ?? 1994 Academic Press. All rights reserved.

Helfenstein, P.; Veverka, J.; Thomas, P.C.; Simonelli, D.P.; Lee, P.; Klaasen, K.; Johnson, T.V.; Breneman, H.; Head, J.W.; Murchie, S.; Fanale, F.; Robinson, M.; Clark, B.; Granahan, J.; Garbeil, H.; McEwen, A.S.; Kirk, R.L.; Davies, M.; Neukum, G.; Mottola, S.; Wagner, R.; Belton, M.; Chapman, C.; Pilcher, C.

1994-01-01

153

Isotopic assessment of sources and processes affecting sulfate and nitrate in surface water and groundwater of Luxembourg.  

PubMed

Surface water and deep and shallow groundwater samples were taken from selected parts of the Grand-Duchy of Luxembourg to determine the isotopic composition of nitrate and sulfate, in order to identify sources and/or processes affecting these solutes. Deep groundwater had sulfate concentrations between 20 and 40 mg/L, delta34S(sulfate) values between -3.0 and -20.0 per thousand, and delta18O(sulfate) values between +1.5 and +5.0 per thousand; nitrate was characterized by concentrations varying between < 0.5 and 10 mg/L, delta15N(nitrate) values of approximately -0.5 per thousand, and delta18O(nitrate) values approximately +3.0 per thousand. In the shallow groundwater, sulfate concentrations ranged from 25 to 30 mg/L, delta34S(sulfate) values from -20.0 to +4.5 per thousand, and delta18O(sulfate) values from approximately +0.5 to +4.5 per thousand; nitrate concentrations varied between approximately 10 and 75 mg/L, delta15N(nitrate) values between +2.5 and +10.0 per thousand, and delta18O(nitrate) values between +1.0 and +3.0 per thousand. In surface water, sulfate concentrations ranged from 10 to 210 mg/L, delta34S(sulfate) values varied between -9.3 and +10.9 per thousand, and delta18O(sulfate) values between +3.0 and +10.7 per thousand were observed. Nitrate concentrations ranged from 10 to 40 mg/L, delta15N(nitrate) values from +6.5 to +12.0 per thousand, and delta18O(nitrate) values from -0.4 to +4.0 per thousand. Based on these data, three sulfate sources were identified controlling the riverine sulfate load. These are soil sulfate, dissolution of evaporites, and oxidation of reduced S minerals in the bedrock. Both groundwater types were predominantly influenced by sulfate from the two latter lithogenic S sources. The deep groundwater and a couple shallow groundwater samples had nitrate derived mainly from soil nitrification. All other sampling sites were influenced by nitrate originating from sewage and/or manure. A decrease in nitrate concentration observed along one of the rivers was attributed to denitrification. It appears that sulfate within Luxembourg's aquatic ecosystem is mainly of lithogenic origin, whereas nitrate is often derived from anthropogenic activities. PMID:12725423

Rock, L; Mayer, B

2002-12-01

154

2060 Chiron - CCD and electronographic photometry  

NASA Technical Reports Server (NTRS)

R-band observations conducted for 2060 Chiron using CCD photometry in November-December 1986 and March 1988 are discussed. While the 1986 observations exhibit neither periodic nor nonperiodic brightness changes ascribable to comet-like activity, the 1988 observations show an 0.6 + or - 0.1 mag brightening that confirms the Tholen et al. (1988) findings and is consistent with the 1978 electronographic photometry presented. The lightcurve amplitudes appear, however, to have remained unchanged from 1978 to 1988, and the image profiles from 1978 are indistinguishable from the stars in 1986 and 1988. It is suggested that Chiron has either been varying nonasteroidally of late, on a 1-2 month timescale, or its intrinsic brightness has been bistable over the past decade.

Bus, Schelte J.; Bowell, Edward; Harris, Alan W.; Hewitt, Anthony V.

1989-01-01

155

Introducing SPA, "The Stellar Photometry Assistant"  

NASA Astrophysics Data System (ADS)

The Stellar Photometry Assistant, SPA, is a stand alone software package for time-series photometry reduction and analysis slated for an initial test release in spring 2008. The goal of SPA is to be simple, powerful, and intuitive. SPA was born out of complications in studying the pulsating DB white dwarf EC20058-5234 (QU Tel) due to the proximity of its nearby companions. SPA also addresses the Whole Earth Telescope's (WET) demand for large scale rapid data reduction from multiple sites. SPA is being developed in Matlab by the Delaware Asteroseismologic Research Center (DARC) in collaboration with the University of Delaware and the Mount Cuba Astronomical Observatory. The need for SPA is addressed, and key features of the program are listed and discussed.

Dalessio, J.; Provencal, J. L.; Kanaan, A.

2008-06-01

156

Lightcurve Photometry Opportunities: 2015 January-March  

NASA Astrophysics Data System (ADS)

We present lists of asteroid photometry opportunities for objects reaching a favorable apparition and having either none or poorly-defined lightcurve parameters. Additional data on these objects will help with shape and spin axis modeling via lightcurve inversion. We also include lists of objects that will be the target of radar observations. Lightcurves for these objects can help constrain pole solutions and/or remove rotation period ambiguities that might not come from using radar data alone.

Warner, Brian D.; Harris, Alan W.; Durech, Josef; Benner, Lance A. M.

2015-01-01

157

Near-Infrared Photometry of Carbon Stars  

Microsoft Academic Search

Near-infrared, JHKL, photometry of 239 Galactic carbon-rich variable stars is\\u000apresented and discussed. From these and published data the stars were\\u000aclassified as Mira or non-Mira variables and amplitudes and pulsation periods,\\u000aranging from 222 to 948 days for the Miras, were determined for most of them. A\\u000acomparison of the colour and period relations with those of similar stars

Patricia A. Whitelock; Michael W. Feast; Freddy Marang; M. A. T. Groenewegen

2006-01-01

158

Variable Star Photometry at West Challow Observatory  

NASA Astrophysics Data System (ADS)

This paper describes the facilities and observing programme of a small personal observatory set up in the UK for CCD photometry of variable stars. Its development has been driven by the belief that committed amateurs can make a valuable scientific contribution to the study of variable stars. Observing projects carried out at WCO are described including examples of Pro-Am collaboration and contributions to the observing programmes of the BAAVSS, AAVSO and CBA.

Boyd, D.

2007-05-01

159

Recalibrating SFD Using SDSS Spectroscopy And Photometry  

NASA Astrophysics Data System (ADS)

We use new measurements of reddening using SDSS photometry and spectroscopy to test the SFD dust map. We find that both the photometric and spectroscopic technique agree on a common SFD calibration that is different from the original SFD calibration by 13%. We find additionally that a Fitzpatrick 1999 reddening law provides a good fit to the reddening law derived from these techniques, while CCM and O'Donnell reddening laws are disfavored.

Schlafly, Eddie; Finkbeiner, D. P.

2011-05-01

160

Material characterization by laser speckle photometry  

NASA Astrophysics Data System (ADS)

The damage and stress conditions of large industrial components have to be tested continuously. Especially welding processes in the field of coal production demand a nondestructive monitoring of internal stresses under an external load. In a first step, a new optical method, Laser Speckle Photometry was used during laboratory welding experiments under tensile and bending loads at high strength construction steels. Laser Speckle Photometry is a fast and contactless method for measuring spatial-temporal dynamics of speckle field with high temporal resolution after local heat excitation. The thermally induced change in the material structure causes changes in the speckle-field, which is formed by a probing laser. The shift of the speckle-field is analyzed by statistical methods, using correlation functions. The result of processing is the two-dimensional distribution of thermal diffusivity coefficient correlated to porosity, materials strain or hardness [1-3]. Here, the results of the welding experiments under load are presented. It is shown, that the Laser Speckle Photometry is a suitable technique for nondestructive monitoring and characterization of internal material stresses under external load.

Bendjus, Beatrice; Cikalova, Ulana; Schreiber, Juergen

2012-10-01

161

CCD Strömvil Photometry of M 37  

NASA Astrophysics Data System (ADS)

We have been working on a program of setting up standards in the Strömvil photometric system and have been doing CCD photometry of globular and open clusters. A previous paper (Boyle et al. BAAS, AAS Meeting #193, #68.08) described the results of observations made in the open cluster M 67, which we are setting up as one of the prime standard fields for Strömvil photometry. Now we discuss our observations of M 37, made on the Vatican Advanced Technology Telescope on Mt. Graham, Arizona. One of us (R.J.) has automated the data processing by a novel method. The Strömvil group is multinational. By use of this innovative automated, yet interactive processing method, one systematically applies the same processing steps to run in IRAF by capturing them as presented in html files and submitting them to the IRAF command language. Use of the mouse avoids errors and accelerates the processing from raw data frames to calibrated photometry. From several G2 V stars in M 67 we have calculated their mean color indices and compare them to stars in M 37 to identify candidate G2 V stars there. Identifying such stars relates to the search for terrestrial exoplanets. Ultimately we will use the calibrated Strömvil indices to make photometric determinations of log g and Teff.

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

2001-12-01

162

Astrometry and photometry in high contrast imaging  

NASA Astrophysics Data System (ADS)

The direct exoplanet imaging field will strongly benefit from the larger aperture and the higher angular resolution achieved by next generation 30+m telescopes. To fully take advantage of these new facilities, one of the biggest challenges that ground-based adaptive optics imaging must overcome is to be able to derive accurate astrometry and photometry with realistic estimate of residual errors. The planet photometry and its astrometry are used to compare with atmospheric models and to fit orbits. If erroneous numbers are found, or if errors are underestimated, spurious fits can lead to unphysical planet characteristics or wrong/unstable orbits. Overestimating the errors also needs to be avoided as it degrades the value of the data. In the high-contrast planet imaging context, we will present various photometry/astrometry biases induced by several noise sources (anisoplanatism, non-Gaussian noise, etc.) or processing techniques (ADI/SSDI/LOCI) that we have uncovered during our ongoing direct exoplanet imaging campaign at Gemini, VLT and Keck. We will describe the procedures that we have implemented to properly estimate those biases. These solutions will be implemented in the Gemini Planet Imager campaign data pipeline and we expect that they will also play a crucial role in any future 30+m survey.

Galicher, Raphael; Marois, Christian

2011-09-01

163

Use of a 3D laser scan technique to compare the surface geometry of the medial coronoid process in dogs affected with medial compartment disease with unaffected controls  

Microsoft Academic Search

Subchondral bone surface geometry of the medial coronoid process was examined in 20 grossly normal elbow joints of adult German Shepherd dogs (GSDs) and compared with results obtained from 10 joints of adult GSDs and 12 joints of adult Rottweilers affected with bilateral fragmentation of the medial coronoid process (FMCP). Additionally, seven dogs (4 GSDs and 3 Rottweilers) with unilateral

Sabine Breit; Kristina Pfeiffer; Reinhard Pichler

2010-01-01

164

Photometry with Multi-anode Microchannel Arrays (mamas) and Charge Injection Devices (cids)  

NASA Technical Reports Server (NTRS)

The characteristics of two kinds of detectors are summarized with emphasis on those aspects that would affect their use in high accuracy astronomical photometry. The first type, the multianode microchannel arrays (MAMA), are a family of pulse counting array detectors. Components and operation principles are reviewed and quantum efficiency, noise characteristics, and dynamic range characteristics are described. The second type, charge injection devices (CID), are discussed in reference to their applicability to photometric detection at optical wavelengths.

Timothy, J. G.

1984-01-01

165

Photometry and models of eight near-Earth asteroids  

NASA Astrophysics Data System (ADS)

We present new observations and models of the shapes and rotational states of the eight near-Earth Asteroids (1580) Betulia, (1627) Ivar, (1980) Tezcatlipoca, (2100) Ra-Shalom, (3199) Nefertiti, (3908) Nyx, (4957) Brucemurray, and (5587) 1990 SB. We also outline some of their solar phase curves, corrected to common reference geometry with the models. Some of the targets may feature sizable global nonconvexities, but the observable solar phase angles were not sufficiently high for confirming these. None is likely to have a very densely cratered surface. We discuss the role of the intermediate topographic scale range in photometry, and surmise that this scale range is less important than large or small scale lengths.

Kaasalainen, Mikko; Pravec, Petr; Krugly, Yurij N.; Šarounová, Lenka; Torppa, Johanna; Virtanen, Jenni; Kaasalainen, Sanna; Erikson, Anders; Nathues, Andreas; ?urech, Josef; Wolf, Marek; Lagerros, Johan S. V.; Lindgren, Mats; Lagerkvist, Claes-Ingvar; Koff, Robert; Davies, John; Mann, Rita; Kušnirák, Peter; Gaftonyuk, Ninel M.; Shevchenko, Vasilij G.; Chiorny, Vasilij G.; Belskaya, Irina N.

2004-01-01

166

THE SIZE AND SURFACE COATING OF NANOSILVER DIFFERENTIALLY AFFECTS BIOLOGICAL ACTIVITY IN BLOOD BRAIN BARRIER (RBEC4) CELLS.  

EPA Science Inventory

Linking the physical properties of nanoparticles with differences in their biological activity is critical for understanding their potential toxicity and mode of action. The influence of aggregate size, surface coating, and surface charge on nanosilver's (nanoAg) movement through...

167

Antimicrobial surfaces containing cationic nanoparticles: How immobilized, clustered, and protruding cationic charge presentation affects killing activity and kinetics.  

PubMed

This work examines how the antimicrobial (killing) activity of net-negative surfaces depends on the presentation of antimicrobial cationic functionality: distributed versus clustered, and flat clusters versus raised clusters. Specifically, the ability to kill Staphylococcus aureus by sparsely distributed 10nm cationic nanoparticles, immobilized on a negative surface and backfilled with a PEG (polyethylene glycol) brush, was compared with that for a dense layer of the same immobilized nanoparticles. Additionally, sparsely distributed 10nm poly-l-lysine (PLL) coils, adsorbed to a surface to produce flat cationic "patches" and backfilled with a PEG brush were compared to a saturated adsorbed layer of PLL. The latter resembled classical uniformly cationic antimicrobial surfaces. The protrusion of the cationic clusters substantially influenced killing but the surface concentration of the clusters had minor impact, as long as bacteria adhered. When surfaces were functionalized at the minimum nanoparticle and patch densities needed for bacterial adhesion, killing activity was substantial within 30min and nearly complete within 2h. Essentially identical killing was observed on more densely functionalized surfaces. Surfaces containing protruding (by about 8nm) nanoparticles accomplished rapid killing (at 30min) compared with surfaces containing similarly cationic but flat features (PLL patches). Importantly, the overall surface density of cationic functionality within the clusters was lower than reported thresholds for antimicrobial action. Also surprising, the nanoparticles were far more deadly when surface-immobilized compared with free in solution. These findings support a killing mechanism involving interfacial stress. PMID:25480668

Fang, Bing; Jiang, Ying; Nüsslein, Klaus; Rotello, Vincent M; Santore, Maria M

2015-01-01

168

Retention and rainfastness of mancozeb as affected by physicochemical characteristics of adaxial apple leaf surface after enhanced UV-B radiation.  

PubMed

It is not clear so far whether alteration of leaf micromorphology and surface wax chemistry due to the impact of environmental factors, such as UV-B radiation, affects retention and rainfastness of applied pesticide solutions. In this study; UV-B treated and untreated adaxial leaf surfaces of apple seedlings (Malus domestica Borkh.) were characterized in terms of chemical composition, micromorphological fine structure, hydrophobicity, and wettability. Furthermore, the retention and rainfastness of applied fungicide mancozeb were studied. The samples were examined 0, 24 and 48 h after ultraviolet (UV)-B radiation (0.022 kW m(-2) for 150 min) The total wax mass, recovered from the adaxial leaf surface, amounted from 0.38 microg cm(-2) (control) up to 0.49 microg cm(-2) (24 h). Chemical composition of surface wax altered, whereas the contact angle of applied water droplets on leaf surface of UV-B treated plants did not change significantly compared to the control. The alteration of surface wax quantity and quality significantly affected retention of a.i.; it increased at a sampling time of 24 h after UV-B irradiation, whereas rainfastness of the fungicide spray solution was not significantly influenced. PMID:17365327

Bringe, Katja; Hunsche, Mauricio; Schmitz-Eiberger, Michaela; Noga, Georg

2007-02-01

169

VizieR Online Data Catalog: Virgo Photometry Catalogue (VPC) (Young+ 1998)  

NASA Astrophysics Data System (ADS)

The Virgo Photometry Catalogue (VPC) contains independently calibrated surface photometry in the U, BJ and RC bands for over 1000 galaxies (including background objects) brighter than BJ25=19.0 in a 23°2 area of the sky centred on R.A., Dec.(1950)= 12h26m, +13°08'. The angular resolution of the photometry varies from band to band and was in each case determined from the FWHM of stellar profiles: 4.75+/-0.1arcsec in the U band, 5.0+/-0.1arcsec in the BJ band and 6.0+/-0.1arcsec in the RC band. The photometry was intended for the derivation of accurate magnitudes and colours and is therefore not of high resolution. Stellar contamination of the galaxy sample is minimal, and cannot exceed about 3 faint-end objects in total (i.e. it is less than about 0.25%). Parameters listed for catalogued galaxies include: equatorial coordinates; morphological types; surface-brightness profile parameters (which preserve the majority of the surface photometry information); U, BJ and RC isophotal magnitudes; U, BJ, RC and [transformed] B total magnitudes; (U-BJ) and (BJ-RC) equal-area colours, apparent angular radii, ellipticities, position angles, heliocentric radial velocities and alternative designations. All total magnitudes and total colours are extrapolated according to the "t" system of Young et al. (1998A&AS..130..173Y). The VPC is based primarily on four UK-Schmidt plates, all of which were scanned using the COSMOS measuring machine at the Royal Observatory Edinburgh. All magnitudes, colours and surface-brightness parameters are derived from numerical integrations of segmented plate-scan data; except for (in 109 cases) saturated and (in 51 cases) inextricably merged images. The latter 51 images are listed in Table 14 (Appendix D) of the original paper, whilst data for the remaining 1129 objects [i.e. including ones for which the VPC photometry is saturated in one or more bands] are listed in the main catalogue. (6 data files).

Young, C. K.; Currie, M. J.

1998-05-01

170

Near Infrared Photometry of Nova Del 2013  

NASA Astrophysics Data System (ADS)

Subjects: Infra-Red, Nova We report RIJHKLM photometry of Nova Del 2013 taken on August 28.13 UT using an As:Si bolometer mounted on the 0.76-m infrared telescope of the University of Minnesota's O'Brien Observatory (Marine on St. Croix, Minnesota, USA). Vega (alpha Lyrae) was used as the standard star. On this date we find: R = 5.6 +/- 0.1, I = 5.2 +/- 0.1, J = 4.5 +/- 0.1, H = 4.7 +/- 0.1, K = 4.7 +/- 0.1, L = 3.3 +/- 0.2, M = +1.8 +/- 0.3.

Cass, C. A.; Carlon, L. R.; Corgan, T. D.; Dykhoff, A. D.; Gehrz, D. R.; Shenoy, P. D.

2013-08-01

171

New BVR Photometry of BL Camelopardalis  

NASA Astrophysics Data System (ADS)

New BVR photometry of the SX Phe star BL Camelopardalis has been secured with the 0.9 m reflector at the BYU West Mountain Observatory. The new data have been used to determine times of maximum light, standardize light curves in each of the three filters, and examine the frequencies that are currently detectable in the light curves from a single location.We acknowledge the Brigham Young University College of Physical and Mathematical Sciences as well as the Department of Physics and Astronomy for continued support of this and other research efforts currently being done at the West Mountain Observatory.

Joner, Michael D.

2015-01-01

172

V photometry of Titania, Oberon, and Triton  

NASA Technical Reports Server (NTRS)

The phase angle and orbital brightness variations of Titania, Oberon, and Triton are presently obtained through analysis of V filter photometry obtained at Mauna Kea in 1982-1983. While Titania and Oberon exhibit magnitude variations with phase angle comparable to those of low-to-moderate albedo asteroids observed within several deg of opposition, Triton's phase variation is distinctly different from these and has a phase coefficient consistent with either a high-albedo regolith or an optically thick nonparticulate scattering layer (perhaps an atmosphere, or an ocean). A low-albedo regolith cannot on the strength of these data be ruled out, however.

Goguen, J. D.; Hammel, H. B.; Brown, R. H.

1989-01-01

173

Charles Nordmann and Multicolour Stellar Photometry  

NASA Astrophysics Data System (ADS)

Charles Nordmann (1881-1940), an astronomer at the Paris Observatory, was the first to determine the effective temperature of stars with his photometre heterochrome, simultaneously and independently of Rosenberg, Wilsing and Scheiner in Germany. He is also the remote precursor of the multicolour photometry of Johnson and Morgan. In spite of the quality of his temperature determinations, which were as good or better than those made by spectrophotometry, he rapidly fell into oblivion because of some failures in his scientific work. We examine his activity in the international context of the time, and explain why he has been forgotten, to be rediscovered only recently.

Lequeux, James

2010-11-01

174

Photometry of six radar target asteroids  

NASA Astrophysics Data System (ADS)

Photoelectric photometry of six Earth-approaching asteroids is presented. The selection criterion was that they were close enough in 1986 to be observed by radar. Rotation periods were obtained for 1986 DA, 3199, 3103, and 1983 RD. 1986 JK and 1986 RA showed no detectable brightness variations during the monitoring time on several nights each, and therefore were either seen pole-on or have long rotation periods. Asteroids 1986 JK and 1986 RA are of taxonomic class C, 1986 DA and 3103 of class X, 1983 RD of class Q, and only 3199 of the class S that was previously believed to be predominant among Earth-approaching asteroids.

Wisniewski, W. Z.

1987-06-01

175

How surface fire in Siberian Scots pine forests affects soil organic carbon in the forest floor: Stocks, molecular structure, and conversion to black carbon (charcoal)  

Microsoft Academic Search

In boreal forests, fire is a frequent disturbance and converts soil organic carbon (OC) to more degradation-resistant aromatic carbon, i.e., black carbon (BC) which might act as a long-term atmospheric-carbon sink. Little is known on the effects of fires on boreal soil OC stocks and molecular composition. We studied how a surface fire affected the composition of the forest floor

Claudia I. Czimczik; Caroline M. Preston; Michael W. I. Schmidt; Ernst-Detlef Schulze

2003-01-01

176

pH gradients and a mirco-pore filter at the luminal surface affect fluxes of propionic acid across guinea pig large intestine  

Microsoft Academic Search

A neutral pH microclimate had been shown at the luminal surface of the large intestine. The aim was to estimate to what extent\\u000a fluxes of propionic acid\\/propionate are affected by changes of the luminal pH when this microclimate is present, largely reduced\\u000a or absent. Fluxes of propionic acid\\/propionate (J\\u000a Pr) across epithelia from the caecum, the proximal and the distal

Roger Busche; Wolfgang von Engelhardt

2007-01-01

177

Quasar Selection using Optical Photometry and Variability  

NASA Astrophysics Data System (ADS)

We used the Non-parametric Bayesian Classification Kernel Density Estimation (NBC KDE) quasar selection algorithm to identify 30,755 type 1 quasar candidates on the Sloan Digital Sky Survey (SDSS) Stripe 82 using the combination of optical photometry and variability. Optical photometry is taken from the SDSS-I/II, while the variability parameters are calculated by fitting the structure function of the object with a power law. Selection was based on a training sample of 13,784 spectroscopically-confirmed type 1 quasars from the SDSS-I/II and the Baryon Oscillation Spectroscopic Survey (BOSS). Using variability alone, colors alone, and combining variability and colors we achieve 85%, 90%, and 95% quasar completeness respectively, with particular improvement in the selection of quasars at 2.7

Peters, Christina M.; Richards, Gordon T.; Myers, Adam D.; Ross, Nicholas

2015-01-01

178

Speckle Interferometry and Photometry of Binary Stars  

NASA Astrophysics Data System (ADS)

Binary orbits, when combined with parallaxes, yield dynamical masses, while photometry of the components restrains astrophysical models. Both are vital to understanding stellar evolution. Speckle interferometry, which is telescope resolution limited as opposed to seeing limited, allows observation of close, short-period binaries. We will use our next-generation, ultra-portable, low cost, EMCCD based speckle camera to observe some 500 binaries. We will confirm Hipparcos/Tycho double star discoveries as candidates for new binaries, classify new pairs by determining if their motion is curved (binary) or linear (optical double), add high-accuracy speckle observations that will allow the first determination of orbits, refine existing orbits by extending orbital coverage with speckle observations, and obtain precise photometry of binary components to link photometric with dynamical masses. For a decade, PI Genet has held undergraduate astronomy research seminars at Cuesta College that feature published student observations of binary stars. This run will demonstrate that student researchers can be an integral part of speckle interferometry runs at major observatories.

Genet, Russell M.; Hartkopf, William I.; Clark, R. Kent; Hardersen, Paul; Wren, Paul; Wallace, Daniel; Gelston, Ryan

2013-08-01

179

WISE photometry of EXor sources and candidates  

NASA Astrophysics Data System (ADS)

We present a collection of WISE photometry of EXor sources and candidates (more recently identified). This represents the first complete survey of such objects in the mid-IR (3.4-22 ?m) that was carried out with the same instrumentation. Two-color diagrams constructed with WISE data evidence a clear segregation between classical and newly identified sources, being these latter characterized by colder (and less evolved) circumstellar disks. By combining 2MASS and WISE data, we obtain spectral energy distributions (SED's) that are compatible with the existence of an inner hole in the circumstellar disk. A compilation of all EXor observations given in the literature at wavelengths very similar to those of WISE is also provided. This allows us to study their mid-IR variability, which has been poorly investigated so far and without any coordination with surveys at shorter wavelengths. The presented WISE photometry and the compilation of the literature data are intended as a first step toward the construction of a significant database in this spectral regime. Preliminary indications on the mechanisms responsible for the luminosity fluctuations are provided.

Antoniucci, S.; Giannini, T.; Lorenzetti, D.

2013-10-01

180

Multicolour photometry of EO Ceti (PB 8783)  

NASA Astrophysics Data System (ADS)

We present the first-look analysis of the high-speed multicolour photometry of the bright V361 Hya-type star EO Ceti ( m V=12.3). The observations were gathered with the three-channel ULTRACAM instrument attached to the 4.2-m William Herschel Telescope. The data set has a total time span of 6.2 d and consists of 31 h simultaneous three colour photometry. The main power regions in all three colours are the same as previously reported in the white light photometric campaigns on EO Ceti. We calculate the frequencies, amplitudes and phases of the significant modes in three colours of the SDSS system, r', g' and u'. The amplitudes of the detected modes are the highest in the u' lightcurve, and the phases are the same in all three colours within the measurement accuracy. The amplitudes of the highest signal-to-noise modes show time variability in all three colours. We analyse the amplitude and phase variations of the five highest signal-to-noise modes in different colours. Even though the amplitudes show variations from night to night, the amplitude ratios are found to be constant to within 2 ? level. This result is promising as it allows us to compare the observed amplitude ratios with theoretically calculated amplitude ratios. This may further constrain the mode identification of the highest amplitude modes in EO Ceti and let us test the proposed seismic and binary evolution models.

Vu?kovi?, M.; Østensen, R. H.; Aerts, C.; Dhillon, V. S.; Marsh, T. R.

2010-10-01

181

FACTORS AFFECTING THE LONG-TERM RESPONSE OF SURFACE WATERS TO ACIDIC DEPOSITION: STATE-OF-THE-SCIENCE  

EPA Science Inventory

Recent intensive study of the causes of surface water acidification has led to numerous hypothesized controlling mechanisms. Among these are the salt-effect reduction of alkalinity, the base cation buffering and sulfate adsorption capacities of soils, availability of weatherable ...

182

Polarimetric Retrievals of Surface and Aerosol Properties in the Region Affected by the Deepwater Horizon Oil Spill  

Microsoft Academic Search

In July 2010, the Research Scanning Polarimeter (RSP) effectuated two flights in two consecutive days over the region affected by the oil spill of the Deepwater Horizon offshore platform. Integrated on the NASA Langley B-200 aircraft, the instrument is deployed together with the High Spectral Resolution Lidar (HSRL), which provides information on the distribution of the aerosol layers beneath the

M. Ottaviani; B. Cairns; J. Chowdhary; K. D. Knobelspiesse; R. A. Ferrare; C. A. Hostetler; J. W. Hair; R. Rogers; M. D. Obland; P. Zhai; Y. Hu

2010-01-01

183

JHK photometry of selected Trojan and Hilda asteroids  

NASA Technical Reports Server (NTRS)

No entirely satisfactory match has been established between the present JHK photometry of selected Hilda and Trojan asteroids and photometry for both main belt asteroids and laboratory samples. It is noted that while the leading Trojans and Hildas exhibit similar and homogeneous JHK colors, the trailing Trojans appear to be more heterogeneous. Charcoal and magnetite provide the best match in terms of JHK colors.

Smith, Dale W.; Johnson, Paul E.; Buckingham, William L.; Shorthill, Richard W.

1992-01-01

184

High Speed Photometry of White Dwarfs with Small Telescopes  

NASA Astrophysics Data System (ADS)

We present high speed photometry of the white dwarfs G29-38 and GD358 obtained with the 0.6m telescope at Mt. Cuba Observatory in Greenville, DE. We also present photometry of the massive pulsating white dwarf BPM37093 obtained with the 0.9m telescope in CTIO as part of the SMARTS consortium.

Provencal, J. L.; Shipman, H. L.; Childers, D.; Nitta, A.

2005-07-01

185

DOPHOT, a CCD photometry program: Description and tests  

Microsoft Academic Search

The design considerations and operational features of DOPHOT, a point-spread function (PSF) fitting photometry program, are described. Some relevant details of the PSF fitting are discussed. The quality of the photometry returned by DOPHOT is assessed via reductions of an 'artificial' globular cluster generated from a list of stars with known magnitudes and colors. Results from comparative tests between DOPHOT

Paul L. Schechter; Mario Mateo; Abhijit Saha

1993-01-01

186

Ten Recent Enhancements To Aperture Photometry Tool  

NASA Astrophysics Data System (ADS)

Aperture Photometry Tool is free, multi-platform, easy-to-install software for astronomical research, as well as for learning, visualizing, and refining aperture-photometry analyses. This mature software has been under development for five years, and is a silent workhorse of the NASA/IPAC Teacher Archive Research Program. Software version 2.1.5 is described by Laher et al., Publications of the Astronomical Society of the Pacific, Vol. 124, No. 917, pp. 737-763, (July 2012). Four software upgrades have been released since the publication, which include new capabilities, increased speed, more user-friendliness, and some minor bug fixes. Visit www.aperturephotometry.org to download the latest version. The enhancements are as follows: 1) Added new Tools menu option to write selected primary-image data to a comma-separated-value file (for importing into Excel); 2) Added a new display of the color-table levels on a separate panel; 3) Added a new tool to measure the angular separation between positions on the thumbnail image, via mouse-cursor drag and release; 4) Added a new tool to overlay an aperture at user-specified coordinates (in addition to aperture overlay via mouse click); 5) Speeded up the source-list tool with optional multithreading in its automatic mode (allowed thread number is user-specifiable); 6) Added a new “Number” column to the output aperture-photometry-table file in order to track the input source order (multithreading reorders the output); 7) Upgraded the source-list tool to accept input source lists containing positions in sexagesimal equatorial coordinates (in addition to decimal degrees, or, alternatively, pixel coordinates); 8) Added a new decimal/sexagesimal converter; 9) Upgraded the source-list creation tool to compute the detection threshold using robust estimates of the local background and local data dispersion, where the user can select the grid and window sizes for these local calculations; and 10) Modified the batch mode to optionally generate a source list. These upgrades increase the software's utility, and more improvements are planned for future releases.

Laher, Russ; Rebull, L. M.; Gorjian, V.

2013-01-01

187

TERMS Photometry of Known Transiting Exoplanets  

E-print Network

The Transit Ephemeris Refinement and Monitoring Survey (TERMS) conducts radial velocity and photometric monitoring of known exoplanets in order to refine planetary orbits and predictions of possible transit times. This effort is primarily directed towards planets not known to transit, but a small sample of our targets consist of known transiting systems. Here we present precision photometry for 6 WASP planets acquired during their transit windows. We perform a Markov Chain Monte Carlo (MCMC) analysis for each planet and combine these data with previous measurements to redetermine the period and ephemerides for these planets. These observations provide recent mid-transit times which are useful for scheduling future observations. Our results improve the ephemerides of WASP-4b, WASP-5b and WASP-6b and reduce the uncertainties on the mid-transit time for WASP-29b. We also confirm the orbital, stellar and planetary parameters of all 6 systems.

Dragomir, Diana; Pilyavsky, Genady; Mahadevan, Suvrath; Ciardi, David R; Gazak, J Zachary; Gelino, Dawn M; Payne, Alan; Rabus, Markus; Ramirez, Solange V; von Braun, Kaspar; Wright, Jason T; Wyatt, Pamela

2011-01-01

188

Simplified Color Photometry Using APASS Data (Abstract)  

NASA Astrophysics Data System (ADS)

(Abstract only) APASS, the AAVSO Photometric All-Sky Survey, now contains 47 million stars and covers 97% of the Northern and Southern hemisphere sky. Its extraordinary coverage means that there are multiple APASS-calibrated stars available for color photometry in the field of view of virtually every amateur image. This paper presents a simplified spreadsheet-based procedure that combines raw photometric data with APASS data to calibrate target objects in the same field of view. The complete photometric equations are reviewed and a simplified form is obtained for use within a limited field of view. Raw photometric data and APASS data for that image from AAVSO are combined on a spreadsheet to produce calibrated photometric measurements of target objects within the field of view. The consistency of the fit to the data is shown graphically. Error terms are tracked through the equations to provide the standard deviation of each measurement.

Dunkel, N.

2014-12-01

189

The surface photometry catalogue of the ESO-Uppsala galaxies  

Microsoft Academic Search

Not Available Bibtex entry for this abstract Preferred format for this abstract (see Preferences) Find Similar Abstracts: Use: Authors Title Keywords (in text query field) Return: Query Results Return items starting with number Query Form Database: Astronomy Physics arXiv e-prints

Andris Lauberts; Edwin A. Valentijn

1989-01-01

190

Voyager photometry of Triton - Haze and surface photometric properties  

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

191

Occurrence of near-surface ozone depletion in the Arctic spring strongly affected by Northern-Hemispheric climate variability  

NASA Astrophysics Data System (ADS)

In the Arctic spring, near-surface ozone can decrease to extremely low levels due to chemical removal catalyzed by halogen radicals. These ozone depletion events (ODEs) are usually accompanied by greatly enhanced surface deposition of reactive gaseous mercury. Here we show the effects of regional climate variability on Arctic ODE frequencies by analyzing surface ozone measurements at three monitoring sites (Barrow, Alert, and Zeppelinfjellet) in the past 30 years. Among the various climate variability indices, the Western Pacific (WP) index has the most significant impact. In years with high ODE frequencies at Barrow and Alert in April, the WP teleconnection pattern tends to be in its negative phase with a weakened storm track from the western Pacific to the Arctic and a strengthened subtropical jet across the Pacific, reducing transport of ozone-rich air masses from mid-latitudes to the Arctic. Analysis of the observations at Zeppelinfjellet indicates a much stronger influence of WP pattern in the 2000s than 1990s. Consequently, the WP index may be used as a proxy to assess ODE frequencies and subsequent environmental impacts in future climate projections.

Koo, J.; Wang, Y.; Jiang, T.; Deng, Y.; Oltmans, S. J.; Solberg, S.

2013-12-01

192

Biodegradable nanoparticles meet the bronchial airway barrier: how surface properties affect their interaction with mucus and epithelial cells.  

PubMed

Despite the wide interest raised by lung administration of nanoparticles (NPs) for the treatment of various diseases, little information is available on their effect toward the airway epithelial barrier function. In this study, the potential damage of the pulmonary epithelium upon exposure to poly(lactide-co-glycolide) (PLGA) NPs has been assessed in vitro using a Calu-3-based model of the bronchial epithelial barrier. Positively and negatively charged as well as neutral PLGA NPs were obtained by coating their surface with chitosan (CS), poloxamer (PF68), or poly(vinyl alcohol) (PVA). The role of NP surface chemistry and charge on the epithelial resistance and mucus turnover, using MUC5AC as a marker, was investigated. The interaction with mucin reduced the penetration of CS- and PVA-coated NPs, while the hydrophilic PF68-coated NPs diffused across the mucus barrier leading to a higher intracellular accumulation. Only CS-coated NPs caused a transient but reversible decrease of the trans-epithelial electrical resistance (TEER). None of the NP formulations increased MUC5AC mRNA expression or the protein levels. These in vitro results highlight the safety of PLGA NPs toward the integrity and function of the bronchial airway barrier and demonstrate the crucial role of NP surface properties to achieve a controlled and sustained delivery of drugs via the pulmonary route. PMID:21981120

Mura, Simona; Hillaireau, Hervé; Nicolas, Julien; Kerdine-Römer, Saadia; Le Droumaguet, Benjamin; Deloménie, Claudine; Nicolas, Valérie; Pallardy, Marc; Tsapis, Nicolas; Fattal, Elias

2011-11-14

193

Large-scale stress factors affecting coral reefs: open ocean sea surface temperature and surface seawater aragonite saturation over the next 400 years  

NASA Astrophysics Data System (ADS)

One-third of the world's coral reefs have disappeared over the last 30 years, and a further third is under threat today from various stress factors. The main global stress factors on coral reefs have been identified as changes in sea surface temperature (SST) and changes in surface seawater aragonite saturation (?arag). Here, we use a climate model of intermediate complexity, which includes an ocean general circulation model and a fully coupled carbon cycle, in conjunction with present-day observations of inter-annual SST variability to investigate three IPCC representative concentration pathways (RCP 3PD, RCP 4.5, and RCP 8.5), and their impact on the environmental stressors of coral reefs related to open ocean SST and open ocean ?arag over the next 400 years. Our simulations show that for the RCP 4.5 and 8.5 scenarios, the threshold of 3.3 for zonal and annual mean ?arag would be crossed in the first half of this century. By year 2030, 66-85% of the reef locations considered in this study would experience severe bleaching events at least once every 10 years. Regardless of the concentration pathway, virtually every reef considered in this study (>97%) would experience severe thermal stress by year 2050. In all our simulations, changes in surface seawater aragonite saturation lead changes in temperatures.

Meissner, K. J.; Lippmann, T.; Sen Gupta, A.

2012-06-01

194

How do Atmospheres Affect Planetary Temperatures? Activity B How do Atmospheres Produce their Effect Upon Surface Temperatures?  

NSDL National Science Digital Library

In this kinesthetic activity, the concept of energy budget is strengthened as students conduct three simulations using play money as units of energy, and students serve as parts of a planetary radiation balance model. Students will determine the energy budget of a planet by manipulating gas concentrations, energy inputs and outputs in the system in this lesson that supports the study of climate on Mars, Mercury, Venus and Earth. The lesson supports understanding of the real-world problem of contemporary climate change. The resource includes a teacher's guide and several student worksheets. This is the second of four activities in the lesson, How do Atmospheres affect planetary temperatures?, within Earth Climate Course: What Determines a Planet's Climate? The resource aims to help students to develop an understanding of our environment as a system of human and natural processes that result in changes that occur over various space and time scales.

195

Diving marine mammals must surface for gas exchange, a necessity that affects all their aquatic activities. By rapidly  

E-print Network

or killer whales Orcinus orca (Le Boeuf and Crocker, 1996). For these reasons, animals such as elephant breathed a mean of 32.7±5.4 times at a rate of 15.3±1.8breathsmin-1 (means ± S.D., N=57). Mean f.2±2.2breathsmin-1 for a mean total of 41.2±5.0breaths during surface intervals lasting 2.6±0.31min. Mean f

Webb, Paul M.

196

Visual and Near-IR Photometry of Nova Del 2013  

NASA Astrophysics Data System (ADS)

We report Visual and Near-IR photometry of Nova Del 2013 taken at the University of Minnesota's O'Brien Observatory (Marine-on-St-Croix, Minnesota, USA). VRIJHKLM photometry were obtained on two successive nights using an AsSi bolometer. Vega (alpha Lyrae) was used as the standard star. Our photometry show: August 16.2 UT: V = 4.8 +/- 0.1, R = 5.4 +/- 0.1, I = 5.2 +/- 0.1, J = 4.4 +/- 0.1, H = 4.3 +/- 0.1, K = 4.3 +/- 0.1, L = 4.5 +/- 0.2.

Gehrz, R. D.; Dykhoff, D. A.; Shenoy, D. P.

2013-08-01

197

Application of an environmental decision support system to a water quality trading program affected by surface water diversions.  

PubMed

Environmental decision support systems (EDSSs) are an emerging tool used to integrate the evaluation of highly complex and interrelated physicochemical, biological, hydrological, social, and economic aspects of environmental problems. An EDSS approach is developed to address hot-spot concerns for a water quality trading program intended to implement the total maximum daily load (TMDL) for phosphorus in the Non-Tidal Passaic River Basin of New Jersey. Twenty-two wastewater treatment plants (WWTPs) spread throughout the watershed are considered the major sources of phosphorus loading to the river system. Periodic surface water diversions to a major reservoir from the confluence of two key tributaries alter the natural hydrology of the watershed and must be considered in the development of a trading framework that ensures protection of water quality. An EDSS is applied that enables the selection of a water quality trading framework that protects the watershed from phosphorus-induced hot spots. The EDSS employs Simon's (1960) three stages of the decision-making process: intelligence, design, and choice. The identification of two potential hot spots and three diversion scenarios enables the delineation of three management areas for buying and selling of phosphorus credits among WWTPs. The result shows that the most conservative option entails consideration of two possible diversion scenarios, and trading between management areas is restricted accordingly. The method described here is believed to be the first application of an EDSS to a water quality trading program that explicitly accounts for surface water diversions. PMID:18592303

Obropta, Christopher C; Niazi, Mehran; Kardos, Josef S

2008-12-01

198

Mutations in Arabidopsis thaliana genes involved in the tryptophan biosynthesis pathway affect root waving on tilted agar surfaces  

NASA Technical Reports Server (NTRS)

Arabidopsis thaliana roots grow in a wavy pattern upon a slanted surface. A novel mutation in the anthranilate synthase alpha 1 (ASA1) gene, named trp5-2wvc1, and mutations in the tryptophan synthase alpha and beta 1 genes (trp3-1 and trp2-1, respectively) confer a compressed root wave phenotype on tilted agar surfaces. When trp5-2wvc1 seedlings are grown on media supplemented with anthranilate metabolites, their roots wave like wild type. Genetic and pharmacological experiments argue that the compressed root wave phenotypes of trp5-2wvc1, trp2-1 and trp3-1 seedlings are not due to reduced IAA biosynthetic potential, but rather to a deficiency in L-tryptophan (L-Trp), or in a L-Trp derivative. Although the roots of 7-day-old seedlings possess higher concentrations of free L-Trp than the shoot as a whole, trp5-2wvc1 mutants show no detectable alteration in L-Trp levels in either tissue type, suggesting that a very localized shortage of L-Trp, or of a L-Trp-derived compound, is responsible for the observed phenotype.

Rutherford, R.; Gallois, P.; Masson, P. H.

1998-01-01

199

Reduced oxide sites and surface corrugation affecting the reactivity, thermal stability, and selectivity of supported Au-Pd bimetallic clusters on SiO2/Si(100).  

PubMed

The morphology and surface elemental composition of Au-Pd bimetallic nanoclusters are reported to be sensitive to and affected by reduced silicon defect sites and structural corrugation on SiO2/Si(100), generated by argon ion sputtering under ultrahigh vacuum (UHV) conditions. Metastable structures of the bimetallic clusters, where Au atoms are depleted from the top surface upon annealing, are stabilized by the interaction with the reduced silica sites, as indicated from CO temperature programmed desorption (TPD) titration measurements. Acetylene conversion to ethylene and benzene has been studied as a probe reaction, revealing the modification of selectivity and reactivity enhancement in addition to improved thermal stability on substrates rich in reduced-silica sites. These observations suggest that these unique sites play an important role in anchoring thermodynamically metastable conformations of supported Au-Pd bimetallic catalysts and dictate their high-temperature activity. PMID:23659535

Gross, Elad; Sorek, Elishama; Murugadoss, Arumugam; Asscher, Micha

2013-05-21

200

Performance of loblolly, Virginia, and shortleaf pine on a reclaimed surface mine as affected by Pisolithus tinctorius ectomycorrhizae and fertilization  

SciTech Connect

The effects of an induced Pisolithus tinctorius infection and broadcast fertilization were studied on the survival and growth of loblolly (Pinus taeda), Virginia (Pinus virginiana), and shortleaf (Pinus echinata) pine outplanted on a reclaimed east Tennessee coal surface mine site. The study site had been previously regraded and hydroseeded with a mixture of ground cover species. After six years, the survival and growth of loblolly pine with P. tinctorius ectomycorrhizae were signficantly improved in comparison with control loblolly pine infected by other ectomycorrhizal symbionts. The response of the Virginia pine to the infection by P. tinctorius was negligible after five years. Fertilization at outplanting significantly reduced the survival of both loblolly and Virginia pine. Fertilization of the shortleaf pine at the start of the third growing season did not result in the drastic mortality exhibited by the loblolly pine, and to a lesser extent the Virginia pine, in response to fertilization at outplanting, but this treatment was still detrimental to the survival of the shortleaf pine after five years. There was a marginal improvement in the survival and growth of the shortleaf pine in response to the infection by P. tinctorius. The effect of fertilization on the growth of all three species was negligible, and the increase in mortality associated with this treatment appeared to be primarily the result of increased competition with the ground cover species. These results indicate that the magnitude of the response exhibited by pines on harsh sites to an ectomycorrhizal infection by P. tinctorius is species dependent. Also, broadcast fertilization is inefficient on surface-mined sites where a vegetative ground cover has been established. 11 refs., 3 tabs.

Walker, R.F.; West, D.C.; McLaughlin, S.B.; Amundsen, C.C.

1985-01-01

201

Spitzer/IRAC Photometry Of The Four Largest Uranian Satellites  

NASA Astrophysics Data System (ADS)

The surfaces of the four largest Uranian satellites are dominated by water ice and a spectrally neutral constituent that is likely carbonaceous in composition. CO2 ice has been detected on Ariel, Umbriel, and Titania, with no detection on the furthest regular Uranian satellite, Oberon (Grundy et al., 2003, 2006). Whether CO2 ice is primordial or is actively produced in the Uranian system is unclear; however, it seems unlikely that primordial CO2 ice would remain exposed on an icy satellite surface over the age of the Solar System. One possible mechanism for producing CO2 ice is bombardment of water ice and carbonaceous material by charged particles caught in Uranus’ magnetic field. Unlike the other large Uranian satellites, Oberon spends part of its orbit outside the confines of Uranus’ magnetic field, which might help explain why CO2 ice has yet to be detected on Oberon. We are using photometric data gathered by the Infrared Array Camera (IRAC), onboard the Spitzer Space Telescope (SST), in order to search for the signature of CO2 ice on Oberon, and confirm its presence on Ariel, Umbriel, and Titania at longer wavelengths than previous studies. IRAC collects data in four different channels, which are centered roughly at 3.6, 4.5, 5.8, and 8.0 µm. Additionally, we are gathering spectroscopic data using SpeX on IRTF, at similar longitudes to the IRAC observations, in order to characterize the distribution of CO2 ice on these icy satellites over a wide range of near-infrared wavelengths. Our preliminary photometry results for Oberon indicate that there is a steep reduction in reflected solar flux from channel 1 to channel 2, suggesting that surface materials are absorbing photons at wavelengths within the bandpass of channel 2. We will present the results of our photometric analysis of the four largest Uranian moons.

Cartwright, Richard; Emery, J.; Rivkin, A.; Trilling, D.

2012-10-01

202

Submillimeter photometry and lightcurves of Ceres and other large asteroids  

NASA Astrophysics Data System (ADS)

Photometry and thermal lightcurves of six large asteroids (1-Ceres, 2-Pallas, 3-Juno, 12-Victoria, 85-Io and 511-Davida) have been observed at 870 ?m (345 GHz) using the MPIfR 19-Channel Bolometer of the Heinrich-Hertz Submillimeter Telescope. Only Ceres displayed a lightcurve with an amplitude (˜50%, peak to peak) that was significantly greater than the uncertainty in the observations. When thermal fluxes and brightness temperatures are corrected for heliocentric distance and albedo, there is a significant relation with the sub-solar latitude of the asteroid, or the local season of the asteroid. No such trend can be found between observations with solar phase angle. These results are evidence that most of the submillimeter thermal radiation is emitted from below the diurnal thermal wave. Comparing the observed trend with model output suggests that the submillimeter radiation from all the asteroids we observed is best modeled by surface material with low thermal inertia (<15 J m -2 s -0.5 K -1, consistent with mid-infrared observations of large main-belt asteroids) and a refractive index closer to unity relative to densities inferred from radar experiments, implying a veneer of material over the asteroid surface with a density less than 1000 kg m -3. More data with better signal-to-noise and aspect coverage could improve these models and constrain physical properties of asteroid surface materials. This would also allow asteroids to be used as calibration sources with accurately known and stable, broadband fluxes at long wavelengths.

Chamberlain, Matthew A.; Lovell, Amy J.; Sykes, Mark V.

2009-08-01

203

Multicolour photometry of edge-on and box/peanut galaxies  

NASA Astrophysics Data System (ADS)

We report the main results of the joint Bulgarian-German project for photometry of edge-on galaxies suspected to have box/peanut structures. CCD images for 30 such galaxies were taken with the 2_m (24 galaxies) and 60_cm (17 galaxies) telescopes as follows: (U), B, V, R, I CCD frames from the 2_m RCC telescope at the Rozhen Observatory with typical resolution 12"/mm = 0.62"/pix with binning and rarely 0.31"/pix, CCD camera "Photometrics" and (B), V, R, I frames on the 60_cm telescope at the Belogradchik Observatory with typical resolution of 27.5"/mm = 0.78"/pix with 3x binning, CCD camera ST--8. Standard stars in selected clusters (M 92, NGC 7790 or M 67), bias, dark and flat field frames were taken every night to calibrate the observations. Typical exposure times were from 2 to 5 min, so the bulge/disk regions were clear presented. All of the objects, observed in the optics, were reduced and classified in an uniform manner. Five galaxies from the list have been reclassified as box/peanut ones. Surface photometry of NGC 5610 and isophote maps of 16 other box/peanut galaxies are presented here. The observations and photometry data are a part of the Bulgarian Virtual Observatory.

Petrov, Georgi; Dettmar, Ralf-Jurgen

204

Detection of Extrasolar Planets by Transit Photometry  

NASA Technical Reports Server (NTRS)

A knowledge of other planetary systems that includes information on the number, size, mass, and spacing of the planets around a variety of star types is needed to deepen our understanding of planetary system formation and processes that give rise to their final configurations. Recent discoveries show that many planetary systems are quite different from the solar system in that they often possess giant planets in short period orbits. The inferred evolution of these planets and their orbital characteristics imply the absence of Earth-like planets near the habitable zone. Information on the properties of the giant-inner planets is now being obtained by both the Doppler velocity and the transit photometry techniques. The combination of the two techniques provides the mass, size, and density of the planets. For the planet orbiting star HD209458, transit photometry provided the first independent confirmation and measurement of the diameter of an extrasolar planet. The observations indicate a planet 1.27 the diameter of Jupiter with 0.63 of its mass (Charbonneau et al. 1999). The results are in excellent agreement with the theory of planetary atmospheres for a planet of the indicated mass and distance from a solar-like star. The observation of the November 23, 1999 transit of that planet made by the Ames Vulcan photometer at Lick Observatory is presented. In the future, the combination of the two techniques will greatly increase the number of discoveries and the richness of the science yield. Small rocky planets at orbital distances from 0.9 to 1.2 AU are more likely to harbor life than the gas giant planets that are now being discovered. However, new technology is needed to find smaller, Earth-like planets, which are about three hundred times less massive than Jupiter-like planets. The Kepler project is a space craft mission designed to discover hundreds of Earth-size planets in and near the habitable zone around a wide variety of stars. To demonstrate that the technology exists to find such small planets, our group has conducted an end-to-end system test. The results of the laboratory tests are presented and show that we are ready to start the search for Earth-size planets.

Borucki, William; Koch, David; Webster, Larry; Dunham, Edward; Witteborn, Fred; Jenkins, Jon; Caldwell, Douglas; Showen, Robert; DeVincenzi, Donald L. (Technical Monitor)

2000-01-01

205

BRITE-Constellation: Nanosatellites for Precision Photometry of Bright Stars  

NASA Astrophysics Data System (ADS)

BRITE-Constellation (where BRITE stands for BRIght Target Explorer) is an international nanosatellite mission to monitor photometrically, in two colours, the brightness and temperature variations of stars generally brighter than mag(V) ? 4 with precision and time coverage not possible from the ground. The current mission design consists of six nanosats (hence Constellation): two from Austria, two from Canada, and two from Poland. Each 7 kg nanosat carries an optical telescope of aperture 3 cm feeding an uncooled CCD. One instrument in each pair is equipped with a blue filter; the other with a red filter. Each BRITE instrument has a wide field of view (?24°), so up to about 15 bright stars can be observed simultaneously, sampled in 32 × 32 pixels sub-rasters. Photometry of additional fainter targets, with reduced precision but thorough time sampling, will be possible through onboard data processing. The BRITE sample is dominated by the most intrinsically luminous stars: massive stars seen at all evolutionary stages, and evolved medium-mass stars at the very end of their nuclear burning phases. The goals of BRITE-Constellation are to (1) measure p- and g-mode pulsations to probe the interiors and ages of stars through asteroseismology; (2) look for varying spots on the stars surfaces carried across the stellar disks by rotation, which are the sources of co-rotating interaction regions in the winds of the most luminous stars, probably arising from magnetic subsurface convection; and (3) search for planetary transits.

Weiss, W. W.; Rucinski, S. M.; Moffat, A. F. J.; Schwarzenberg-Czerny, A.; Koudelka, O. F.; Grant, C. C.; Zee, R. E.; Kuschnig, R.; Mochnacki, St.; Matthews, J. M.; Orleanski, P.; Pamyatnykh, A.; Pigulski, A.; Alves, J.; Guedel, M.; Handler, G.; Wade, G. A.; Zwintz, K.

2014-06-01

206

The expected Gaia revolution in asteroid science: Photometry and spectroscopy  

NASA Astrophysics Data System (ADS)

Gaia is expected to produce a major revolution in our knowledge of the asteroids. Apart from a huge improvement in the accuracy of the orbital elements of these objects, something which is a ''natural'' consequence of the unprecedented astrometric accuracy of Gaia, we can also expect that the photometric and spectrophotometric performances of the Gaia detectors will be such to substantially move ahead the frontier of the domain of physical characterization of asteroids by means of remote observations. A list of physical properties, that will be derived from the analysis of the detections corresponding to different observed transits of each object in the Gaia focal plane during five years of operational activity, includes masses, sizes, average densities, spin properties, reflectance spectra, albedos, as well as a new taxonomic classification. In this review, the focus will be on Gaia photometry and spectrophotometry. The method of photometric inversion of sparse photometric data developed to reduce Gaia photometric data of asteroids will be described, and its expected performances will be discussed. In particular, the choice of assuming for the objects the shapes of ideal triaxial ellipsoids, fairly simplistic in an era in which much more refined shape models are currently used in photometric inversion methods, will be justified by the need of minimizing the CPU time needed to process data for hundreds of thousands of objects in a reasonable time. The processing of spectrophotometric data will be also described. These data will produce a huge data set of reflectance spectra of asteroids. A particular advantage of these data will be that of including also the blue part of the spectrum, which has been substantially lost since the epoch in which the CCD detectors have replaced the older photomultipliers used for UBVRI photometry. The big data set of new asteroid spectra will be also used to develop a new asteroid taxonomy, used new algorithms developed for this purpose. Coupled with the determination of reasonably accurate masses and bulk densities for the biggest 100 asteroids, Gaia data will open a new era in asteroid science, and will allow us to answer some fundamental questions, including the relation between internal structure and surface properties. The resulting post-Gaia scenario in asteroid science will be very much improved with respect to the current state of the art.

Cellino, A.

2014-07-01

207

Affective Technology, Affective Management, towards Affective Society  

Microsoft Academic Search

In this paper, the term affective is defined as “being capable to evoke affects in people’s mind” or “being capable to deliberate affects to be evoked in people’s\\u000a mind”. This paper discusses potential impact of concept of affectiveness on development of technological products and services, management, and value systems of societies.

Hiroyuki Umemuro

2009-01-01

208

WIYN Open Cluster Study: UBVRI Photometry of NGC 2158  

NASA Astrophysics Data System (ADS)

We present WIYN 0.9m HDI UBVRI photometry of NGC 2158, a very rich, intermediate-aged, open cluster located near the galactic anti-center. We report derived values for the cluster age, distance, reddening.

Taverne, Luke T.; Steinhauer, Aaron J.; Deliyannis, Constantine P.

2015-01-01

209

Photoelectric Photometry of Asteriods 29 Amphitrite and 88 Thisbe  

Microsoft Academic Search

Photoelectric photometry observations of the asteroids 29 Amphitrite and 88 Thisbe were made from North Valley Stream Observatory during the period August 29 to September 1, 1986 UT. The lightcurves for both asteroids are consistent with previously determined rotation periods.

F. J. Melillo

1987-01-01

210

Photometry and transit-timing analysis for eleven transiting exoplanets  

E-print Network

This thesis presents time-series photometry of transits of 11 different extrasolar planets. Observations were conducted with the Fred L. Whipple Observatory 1.2m telescope and the Wise Observatory im telescope, in standard ...

De Kleer, Katherine Rebecca

2009-01-01

211

A catalogue of IJK photometry of Planetary Nebulae with DENIS  

E-print Network

Near-infrared photometry of planetary nebulae (PNe) allows the classification of those objects. We present the largest homogeneous sample so far, obtained with the Deep Near Infrared Southern Sky Survey (DENIS).

S. Schmeja; S. Kimeswenger

2001-05-15

212

Identification of surface residues of the monocyte chemotactic protein 1 that affect signaling through the receptor CCR2.  

PubMed

The CC chemokine, monocyte chemotactic protein, 1 (MCP-1) functions as a major chemoattractant for T-cells and monocytes by interacting with the seven-transmembrane G protein-coupled receptor CCR2. To identify which residues of MCP-1 contribute to signaling though CCR2, we mutated all the surface-exposed residues to alanine and other amino acids and made some selective large changes at the amino terminus. We then characterized the impact of these mutations on three postreceptor pathways involving inhibition of cAMP synthesis, stimulation of cytosolic calcium influx, and chemotaxis. The results highlight several important features of the signaling process and the correlation between binding and signaling: The amino terminus of MCP-1 is essential as truncation of residues 2-8 ([1+9-76]hMCP-1) results in a protein that cannot stimulate chemotaxis. However, the exact peptide sequence may be unimportant as individual alanine mutations or simultaneous replacement of residues 3-6 with alanine had little effect. Y13 is also important and must be a large nonpolar residue for chemotaxis to occur. Interestingly, both Y13 and [1+9-76]hMCP-1 are high-affinity binders and thus affinity of these mutants is not correlated with ability to promote chemotaxis. For the other surface residues there is a strong correlation between binding affinity and agonist potency in all three signaling pathways. Perhaps the most interesting observation is that although Y13A and [1+9-76]hMCP are antagonists of chemotaxis, they are agonists of pathways involving inhibition of cAMP synthesis and, in the case of Y13A, calcium influx. These results demonstrate that these two well-known signaling events are not sufficient to drive chemotaxis. Furthermore, it suggests that specific molecular features of MCP-1 induce different conformations in CCR2 that are coupled to separate postreceptor pathways. Therefore, by judicious design of antagonists, it should be possible to trap CCR2 in conformational states that are unable to stimulate all of the pathways required for chemotaxis. PMID:10587439

Jarnagin, K; Grunberger, D; Mulkins, M; Wong, B; Hemmerich, S; Paavola, C; Bloom, A; Bhakta, S; Diehl, F; Freedman, R; McCarley, D; Polsky, I; Ping-Tsou, A; Kosaka, A; Handel, T M

1999-12-01

213

The RSA survey of dwarf galaxies, 1: Optical photometry  

NASA Technical Reports Server (NTRS)

We present detailed surface photometry, based on broad B-band charge coupled device (CCD) images, of about 80 dwarf galaxies. Our sample represents approximately 10% of all dwarf galaxies identified in the vicinity of Revised Shapley-Ames (RSA) galaxies on high resolution blue photographic plates, referred to as the RSA survey of dwarf galaxies. We derive global properties and radial surface brightness profiles, and examine the morphologies. The radial surface brightness profiles of dwarf galaxies, whether early or late type, display the same varieties in shape and complexity as those of classical giant galaxies. Only a few are well described by a pure r(exp 1/4) law. Exponential profiles prevail. Features typical of giant disk galaxies, such as exponential profiles with a central depression, lenses, and even, in one case (IC 2041), a relatively prominent bulge are also found in dwarf galaxies. Our data suggest that the central region evolves from being bulge-like, with an r(exp 1/4) law profile, in bright galaxies to a lens-like structure in dwarf galaxies. We prove detailed surface photometry to be a helpful if not always sufficient tool in investigating the structure of dwarf galaxies. In many cases kinematic information is needed to complete the picture. We find the shapes of the surface brightness profiles to be loosely associated with morphological type. Our sample contains several new galaxies with properties intermediate between those of giant and dwarf ellipticals (but no M32-like objects). This shows that such intermediate galaxies exist so that at least a fraction of early-type dwarf ellipticals is structurally related to early-type giants instead of belonging to a totally unrelated, disjunct family. This supports an origin of early-type dwarf galaxies as originally more massive systems that acquired their current morphology as a result of substantial, presumable supernova-driven, mass loss. On the other hand, several early-type dwarfs in our sample are merger candidates. Merger events may lead to anisotropic velocity distributions in systems of any luminosity, including dwarfs. The RSA sample of dwarf galaxies is more likely to contain mergers because, in contrast to earlier dwarf galaxy surveys that have focused on clusters and rich groups of galaxies, the RSA dwarfs are typically located in low density environments. The occurrence of mergers among dwarf galaxies is of interest in connection with the rapid evolution of faint blue galaxy counts at redshift z less than 1 which suggests that dwarf galaxies were about five times more numerous in the recent past. Finally, our sample contains several examples of late-type dwarfs and 'transition' types that are potential precursors of nucleated early-type dwarfs. All the above processes--mass loss, mergers, astration--are likely to have contributed to the formation of the current population of diffuse early-type dwarfs. A few new redshifts of dwarf galaxies are reported in this paper.

Vader, J. Patricia; Chaboyer, Brian

1994-01-01

214

Binary Star Synthetic Photometry and Distance Determination Using BINSYN  

NASA Astrophysics Data System (ADS)

This paper extends synthetic photometry to components of binary star systems. The paper demonstrates accurate recovery of single star photometric properties for four photometric standards, Vega, Sirius, GD153, and HD209458, ranging over the HR diagram, when their model synthetic spectra are placed in fictitious binary systems and subjected to synthetic photometry processing. Techniques for photometric distance determination have been validated for all four photometric standards.

Linnell, Albert P.; DeStefano, Paul; Hubeny, Ivan

2013-09-01

215

BINARY STAR SYNTHETIC PHOTOMETRY AND DISTANCE DETERMINATION USING BINSYN  

SciTech Connect

This paper extends synthetic photometry to components of binary star systems. The paper demonstrates accurate recovery of single star photometric properties for four photometric standards, Vega, Sirius, GD153, and HD209458, ranging over the HR diagram, when their model synthetic spectra are placed in fictitious binary systems and subjected to synthetic photometry processing. Techniques for photometric distance determination have been validated for all four photometric standards.

Linnell, Albert P. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195-1580 (United States); DeStefano, Paul [8508B Midvale Ave. North, Seattle, WA 98103 (United States); Hubeny, Ivan, E-mail: linnell@astro.washington.edu, E-mail: pdestefa@uw.edu, E-mail: hubeny@as.arizona.edu [Steward Observatory and Department of Astronomy, University of Arizona, Tucson, AZ 85721 (United States)

2013-09-15

216

DOPHOT, a CCD photometry program: Description and tests  

NASA Technical Reports Server (NTRS)

The design considerations and operational features of DOPHOT, a point-spread function (PSF) fitting photometry program, are described. Some relevant details of the PSF fitting are discussed. The quality of the photometry returned by DOPHOT is assessed via reductions of an 'artificial' globular cluster generated from a list of stars with known magnitudes and colors. Results from comparative tests between DOPHOT and DAOPHOT using this synthetic cluster and real data are also described.

Schechter, Paul L.; Mateo, Mario; Saha, Abhijit

1993-01-01

217

DOE-EMSP Final Report: Characterization of Changes in Colloid and DNAPL Affecting Surface Chemistry and Remediation  

SciTech Connect

The waste disposal to the M-area basin and A-14 outfall at the Savannah River Department of Energy facility in Aiken SC (USA) included a wide variety of inorganic aqueous flows and organic solvents in the form of dense non-aqueous phase liquids (DNAPL). The DNAPL has migrated through the subsurface resulting in widespread groundwater contamination. The goal of this research was to identify and quantify processes that could have affected the migration and remediation of the DNAPL in the subsurface. It was hypothesized that the variety of waste disposed at this site could have altered the mineral, microbial and DNAPL properties at this site relative to other DNAPL sites. The DNAPL was determined to have a very low interfacial tension and is suspected to be distributed in fine grained media, thereby reducing the effectiveness of soil vapor extraction remediation efforts. Although the DNAPL is primarily comprised of tetrachloroethene and trichloroethane, it also contains organic acids and several heavy metals. Experimental results suggest that iron from the aqueous and DNAPL phases undergoes precipitation and dechlorination reactions at the DNAPL-water interface, contributing to the low interfacial tension and acidity of the DNAPL. Biological activity in the contaminated region can also contribute to the low interfacial tension. PCE degrading bacteria produce biosurfactants and adhere to the DNAPL-water interface when stressed by high tetrachloroethene or low dissolved oxygen concentrations. The presence of iron can reduce the interfacial tension by nearly an order of magnitude, while the PCE degraders reduced the interfacial tension by nearly 50%. Abiotic changes in the mineral characteristics were not found to be substantially different between contaminated and background samples. The research completed here begins to shed some insight into the complexities of DNAPL fate and migration at sites where co-disposal of many different waste products occurred. Quantifying the low interfacial tension of the SRS DNAPL helps to formulate a new conceptual picture of the subsurface DNAPL migration and provides an explanation of the limited effectiveness of remediation efforts. Alternative designs for remediation that are more effective for sites with DNAPL in fine grained media are required.

Susan E. Powers; Stefan J. Grimberg; Miles Denham

2007-02-07

218

Deep CCD Photometry of Old Open Clusters  

NASA Astrophysics Data System (ADS)

Ages and distance moduli for the open clusters NGC 2204, Berkeley 39, NGC 2477, and Melotte 66 are constrained by comparing the theoretical models developed by Bertelli et al. (1994, A&A, 106, 235) to the observed cluster color-magnitude diagrams which are based on deep CCD photometry. Out of a set of comparison models, no single isochrone was superior to the others in describing an observed color-magnitude diagram. Thus, a best fitting model was selected based not only on the match to an observed color-magnitude diagram, but also on the isochrone's agreement with adopted values for the cluster's metallicity and reddening. The range of otherwise acceptable models help quantify the age and distance modulus uncertainty of each cluster. Based on the best fitting models NGC 2204 is 1.6(+0.9}_{-0.3) Gyrs old with (m-M)_o = 13.0(+0.5}_{-0.4) , Berkeley 39 has an age of 6(+2}_{-1) Gyrs with (m-M)_o = 12.9+/-0.2, NGC 2477 is 1(+0.3}_{-0.2) Gyr old with (m-M)_o = 10.5(+0.4}_{-0.3) , and Melotte 66 has an age of 4+/-1 Gyrs with (m-M)_o = 13.2(+0.3}_{-0.1) .

Kassis, Marc; Janes, Kenneth A.; Friel, Eileen D.; Phelps, Randy L.

1997-05-01

219

Recent Advances in Video Meteor Photometry  

NASA Technical Reports Server (NTRS)

One of the most common (and obvious) problems with video meteor data involves the saturation of the output signal produced by bright meteors, resulting in the elimination of such meteors from photometric determinations. It is important to realize that a "bright" meteor recorded by intensified meteor camera is not what would be considered "bright" by a visual observer - indeed, many Generation II or III camera systems are saturated by meteors with a visual magnitude of 3, barely even noticeable to the untrained eye. As the relatively small fields of view (approx.30 ) of the camera systems captures at best modest numbers of meteors, even during storm peaks, the loss of meteors brighter than +3 renders the determination of shower population indices from video observations even more difficult. Considerable effort has been devoted by the authors to the study of the meteor camera systems employed during the Marshall Space Flight Center s Leonid ground-based campaigns, and a calibration scheme has been devised which can extend the useful dynamic range of such systems by approximately 4 magnitudes. The calibration setup involves only simple equipment, available to amateur and professional, and it is hoped that use of this technique will make for better meteor photometry, and move video meteor analysis beyond the realm of simple counts.

Swift, Wesley R.; Suggs, Robert M.; Meachem, Terry; Cooke, William J.

2003-01-01

220

Snow cover and ground surface temperature on a talus slope affected by mass movements. Veleta cirque, Sierra Nevada, Spain  

NASA Astrophysics Data System (ADS)

This paper analyses the thermal ground behaviour on an alpine talus slope located at the foot of the north wall of the glacial cirque on the Pico del Veleta (3398 m, 37°03'21''N, 3°21'57''W, MAAT: -0,4°C) in Sierra Nevada, SE Spain. There are frequent mass movements on this talus slope, particularly in its central section, caused by the abundant presence of fine-grained sediment and by the water from snowmelt and/or ice degradation in the ground or permafrost (Gómez et al., 2003). To determine the snowmelt pattern and ocurrence of permafrost, a continuous ground surface temperature was kept by installing 6 mini-loggers (HOBO Pendant) along the descending profile of the central talus, which is 170 m long with altitudes ranging from 3180 m at the higher end to 3085 m at the lower end. A thermal borehole was also installed at a depth of 2 m at the base of the slope on an active rock glacier. The results obtained for the period October 2008 - September 2009 show that, in contrast to alpine talus slopes (Luetschg et. al., 2004; Lambiel and Pieracci, 2008), the upper part of the slope is characterized by mean annual ground surface temperatures (MAGST) lower than at the base of the talus, possibly due to the effect of the shadow of the cirque wall. The MAGST oscillate between 0.592°C at the station near the slope apex (S2) and 1.836°C at the station near the base (S5). In winter-spring, when the talus slope is covered with snow, the GST are stabilized at all stations between mid-October and early November. The minimum GST, which express the BTS conditions, oscillate between 0.232 and 0.01°C, depending on the month, with lowest values recorded during the month of April. Only one station (S3, mid-slope) recorded negative values (max. value : - 0.549°C in December and - 0.211 in April ). In summer, the snow disappears fairly quickly between mid- and late July on the intermediate stretch of the talus slope (S3, S4, S6), where the majority of the flows detected occur. In the mid-upper part (S5, S2) the thaw occurs in mid-August. The GST data provide evidence of the current absence of permafrost along the talus slope profile, although some years ago it was detected using BTS methods (Gómez et al., 2003. Gómez-Ortiz, A., Palacios, D., Luengo, E., Tanarro, L. M.; Schulte, L. and Ramos, M., 2003. Talus instability in a recent deglaciation area and its relationship to buried ice and snow cover evolution (Picacho del Veleta, Sierra Nevada, Spain). Geografisca Annaler 85 A (2), 165-182. Lambiel, C. and Pieracci, K. 2008. Permafrost distribution in talus slopes located within the alpine periglacial belt, Swiss Alps. Permafrost and Periglac. Process. 19: 293-304 Luetschg, M.; Stoeckli, M.; Lehning, M.; Haeberli, W., and Ammann, W. 2004. Temperatures in two boreholes at Flüela Pass, Eastern Swiss Alps: the effect of snow redistribution on permafrost distribution patterns in high mountain areas. Permafrost and Periglac. Process. 15: 283-297. Research funded by CGL2009-7343 project, Government of Spain.

Tanarro, L. M.; Palacios, D.; Gómez-Ortiz, A.; Salvador-Franch, F.

2012-04-01

221

Inflammation-Associated Nitrotyrosination Affects TCR Recognition through Reduced Stability and Alteration of the Molecular Surface of the MHC Complex  

PubMed Central

Nitrotyrosination of proteins, a hallmark of inflammation, may result in the production of MHC-restricted neoantigens that can be recognized by T cells and bypass the constraints of immunological self-tolerance. Here we biochemically and structurally assessed how nitrotyrosination of the lymphocytic choriomeningitis virus (LCMV)-associated immunodominant MHC class I-restricted epitopes gp33 and gp34 alters T cell recognition in the context of both H-2Db and H-2Kb. Comparative analysis of the crystal structures of H-2Kb/gp34 and H-2Kb/NY-gp34 demonstrated that nitrotyrosination of p3Y in gp34 abrogates a hydrogen bond interaction formed with the H-2Kb residue E152. As a consequence the conformation of the TCR-interacting E152 was profoundly altered in H-2Kb/NY-gp34 when compared to H-2Kb/gp34, thereby modifying the surface of the nitrotyrosinated MHC complex. Furthermore, nitrotyrosination of gp34 resulted in structural over-packing, straining the overall conformation and considerably reducing the stability of the H-2Kb/NY-gp34 MHC complex when compared to H-2Kb/gp34. Our structural analysis also indicates that nitrotyrosination of the main TCR-interacting residue p4Y in gp33 abrogates recognition of H-2Db/gp33-NY complexes by H-2Db/gp33-specific T cells through sterical hindrance. In conclusion, this study provides the first structural and biochemical evidence for how MHC class I-restricted nitrotyrosinated neoantigens may enable viral escape and break immune tolerance. PMID:22431983

Sandalova, Tatyana; Webb, John R.; Achour, Adnane

2012-01-01

222

FIXING THE U-BAND PHOTOMETRY OF TYPE Ia SUPERNOVAE  

SciTech Connect

We present previously unpublished photometry of supernovae 2003gs and 2003hv. Using spectroscopically derived corrections to the U-band photometry, we reconcile U-band light curves made from imagery with the Cerro Tololo 0.9 m, 1.3 m, and Las Campanas 1 m telescopes. Previously, such light curves showed a 0.4 mag spread at one month after maximum light. This gives us hope that a set of corrected ultraviolet light curves of nearby objects can contribute to the full utilization of rest-frame U-band data of supernovae at redshift {approx}0.3-0.8. As pointed out recently by Kessler et al. in the context of the Sloan Digital Sky Survey supernova search, if we take the published U-band photometry of nearby Type Ia supernovae at face value, there is a 0.12 mag U-band anomaly in the distance moduli of higher redshift objects. This anomaly led the Sloan survey to eliminate from their analyses all photometry obtained in the rest-frame U-band. The Supernova Legacy Survey eliminated observer frame U-band photometry, which is to say nearby objects observed in the U-band, but they used photometry of high-redshift objects no matter in which band the photons were emitted.

Krisciunas, Kevin; Bastola, Deepak; Suntzeff, Nicholas B. [Department of Physics and Astronomy, Texas A and M University, 4242 TAMU, College Station, TX 77843-4242 (United States); Espinoza, Juan; Gonzalez, David [Cerro Tololo Inter-American Observatory, Casilla 603, La Serena (Chile); Gonzalez, Luis; Gonzalez, Sergio; Hsiao, Eric Y.; Morrell, Nidia; Phillips, Mark M. [Las Campanas Observatory, Casilla 601, La Serena (Chile); Hamuy, Mario, E-mail: krisciunas@physics.tamu.edu, E-mail: suntzeff@physics.tamu.edu, E-mail: jespinoza@ctio.noao.edu, E-mail: hsiao@lco.cl, E-mail: nmorrell@lco.cl, E-mail: mmp@lco.cl, E-mail: mhamuy@das.uchile.cl [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago (Chile)

2013-01-01

223

NEW UBVRI PHOTOMETRY OF 234 M33 STAR CLUSTERS  

SciTech Connect

This is the second paper of our series. In this paper, we present UBVRI photometry for 234 star clusters in the field of M33. For most of these star clusters, there is photometry in only two bands in previous studies. The photometry of these star clusters is performed using archival images from the Local Group Galaxies Survey, which covers 0.8 deg{sup 2} along the major axis of M33. Detailed comparisons show that, in general, our photometry is consistent with previous measurements, and in particular that our photometry is in good agreement with that of Zloczewski and Kaluzny. Combined with star cluster photometry in previous studies, we present some results: none of the M33 youngest clusters ({approx}10{sup 7} yr) have masses approaching 10{sup 5} M{sub Sun }, and comparisons with models of simple stellar populations suggest a large range of ages for M33 star clusters and some as old as the Galactic globular clusters.

Ma Jun, E-mail: majun@nao.cas.cn [National Astronomical Observatories, Chinese Academy of Sciences, A20 Datun Road, Chaoyang District, Beijing 100012 (China); Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

2013-04-15

224

Stellar Magnetism in the Era of Space-Based Precision Photometry  

NASA Astrophysics Data System (ADS)

The advent of precision space-based photometric missions such as MOST, CoRoT and Kepler has revealed stellar magnetic activity in unprecedented detail. These observations enable new investigations into the fundamental nature of stellar magnetism by furthering our understanding of the stellar rotation and differential rotation that generate the field, and the photometric variability caused by the surface manifestations of the field. In the case of stars with planetary candidates, these data also offer synergy between studies of stars and planets. Here, I review the possibilities and challenges for deepening our understanding of magnetism in solar-like stars in the era of space-based precision photometry.

Walkowicz, Lucianne M.

2014-08-01

225

Changes in the surface features of choroid plexus of the rat following the administration of acetazolamide and other drugs which affect CSF secretion.  

PubMed Central

The surface of the choroid plexus of the rat was examined by scanning electron microscopy before and after administration of acetazolamide and other drugs (cardiac glycosides and pilocarpine) which affect the rate of secretion of the CSF. In control animals, bleb-covered cells were more common on the IVth ventricle choroid plexus than on the lateral ventricle choroid plexus (20 per specimen compared to 0-3 per specimen). Following administration of acetazolamide the number of bleb-covered cells was reduced significantly (P less than 0-001). The effects of the other drugs were less well defined. Since acetazolamide is known to interfere with the active transport of the extra chloride ions normally added to the CSF in the IVth ventricle, it is suggested that the bleb-covered cells of the IVth ventricle choroid plexus are the specific site for chloride secretion. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 PMID:1240096

Collins, P; Morriss, G M

1975-01-01

226

Dissection of the functional surface of an anti-insect excitatory toxin illuminates a putative "hot spot" common to all scorpion beta-toxins affecting Na+ channels.  

PubMed

Scorpion beta-toxins affect the activation of voltage-sensitive sodium channels (NaChs). Although these toxins have been instrumental in the study of channel gating and architecture, little is known about their active sites. By using an efficient system for the production of recombinant toxins, we analyzed by point mutagenesis the entire surface of the beta-toxin, Bj-xtrIT, an anti-insect selective excitatory toxin from the scorpion Buthotus judaicus. Each toxin mutant was purified and analyzed using toxicity and binding assays, as well as by circular dichroism spectroscopy to discern the differences among mutations that caused structural changes and those that specifically affected bioactivity. This analysis highlighted a functional discontinuous surface of 1405 A(2), which was composed of a number of non-polar and three charged amino acids clustered around the main alpha-helical motif and the C-tail. Among the charged residues, Glu(30) is a center of a putative "hot spot" in the toxin-receptor binding-interface and is shielded from bulk solvent by a hydrophobic "gasket" (Tyr(26) and Val(34)). Comparison of the Bj-xtrIT structure with that of other beta-toxins that are active on mammals suggests that the hot spot and an adjacent non-polar region are spatially conserved. These results highlight for the first time structural elements that constitute a putative "pharmacophore" involved in the interaction of beta-toxins with receptor site-4 on NaChs. Furthermore, the unique structure of the C-terminal region most likely determines the specificity of excitatory toxins for insect NaChs. PMID:14672947

Cohen, Lior; Karbat, Izhar; Gilles, Nicolas; Froy, Oren; Corzo, Gerardo; Angelovici, Ruthie; Gordon, Dalia; Gurevitz, Michael

2004-02-27

227

An investigation into the potential for different surface-coated quantum dots to cause oxidative stress and affect macrophage cell signalling in vitro.  

PubMed

The aim of this study was to investigate the ability of a series of different surface-coated quantum dots (QDs) to cause oxidative stress and affect cell signalling in J774.A1 macrophages. Organic QDs caused a significant (p < 0.001) decrease in glutathione (GSH) levels over 24 h, while COOH and NH(2) (PEG) QDs induced a significant decrease (p < 0.05) in GSH at 6 and 24 h only. J774.A1 cytosolic Ca(2+) concentration significantly increased (p < 0.01) 30 min after treatment with all QDs. Trolox was, however, able to prevent the COOH and NH(2) (PEG) QD-induced Ca(2+) signal, but not the organic QD induced effect. All QDs tested were observed to have a relatively low ability to stimulate increased expression of the pro-inflammatory cytokine tumour necrosis factor-alpha (TNF-alpha). In conclusion, QDs differ in their interactions with macrophages according to their specific surface properties. PMID:20795892

Clift, Martin J D; Boyles, Matthew S P; Brown, David M; Stone, Vicki

2010-06-01

228

Surface Orientation Affects the Direction of Cone Growth by Leptolyngbya sp. Strain C1, a Likely Architect of Coniform Structures Octopus Spring (Yellowstone National Park)  

PubMed Central

Laminated, microbially produced stromatolites within the rock record provide some of the earliest evidence for life on Earth. The chemical, physical, and biological factors that lead to the initiation of these organosedimentary structures and shape their morphology are unclear. Modern coniform structures with morphological features similar to stromatolites are found on the surface of cyanobacterial/microbial mats. They display a vertical element of growth, can have lamination, can be lithified, and observably grow with time. To begin to understand the microbial processes and interactions required for cone formation, we determined the phylogenetic composition of the microbial community of a coniform structure from a cyanobacterial mat at Octopus Spring, Yellowstone National Park, and reconstituted coniform structures in vitro. The 16S rRNA clone library from the coniform structure was dominated by Leptolyngbya sp. Other cyanobacteria and heterotrophic bacteria were present in much lower abundance. The same Leptolyngbya sp. identified in the clone library was also enriched in the laboratory and could produce cones in vitro. When coniform structures were cultivated in the laboratory, the initial incubation conditions were found to influence coniform morphology. In addition, both the angle of illumination and the orientation of the surface affected the angle of cone formation demonstrating how external factors can influence coniform, and likely, stromatolite morphology. PMID:23241986

Reyes, Kristina; Gonzalez, Nicolas I.; Stewart, Joshua; Ospino, Frank; Nguyen, Dickie; Cho, David T.; Ghahremani, Nahal; Spear, John R.

2013-01-01

229

Episodic ataxia type 1 mutations affect fast inactivation of K+ channels by a reduction in either subunit surface expression or affinity for inactivation domain.  

PubMed

Episodic ataxia type 1 (EA1) is an autosomal dominant disorder characterized by continuous myokymia and episodic attacks of ataxia. Mutations in the gene KCNA1 that encodes the voltage-gated potassium channel Kv1.1 are responsible for EA1. In several brain areas, Kv1.1 coassembles with Kv1.4, which confers N-type inactivating properties to heteromeric channels. It is therefore likely that the rate of inactivation will be determined by the number of Kv1.4 inactivation particles, as set by the precise subunit stoichiometry. We propose that EA1 mutations affect the rate of N-type inactivation either by reduced subunit surface expression, giving rise to a reduced number of Kv1.1 subunits in heterotetramer Kv1.1-Kv1.4 channels, or by reduced affinity for the Kv1.4 inactivation domain. To test this hypothesis, quantified amounts of mRNA for Kv1.4 or Kv1.1 containing selected EA1 mutations either in the inner vestibule of Kv1.1 on S6 or in the transmembrane regions were injected into Xenopus laevis oocytes and the relative rates of inactivation and stoichiometry were determined. The S6 mutations, V404I and V408A, which had normal surface expression, reduced the rate of inactivation by a decreased affinity for the inactivation domain while the mutations I177N in S1 and E325D in S5, which had reduced subunit surface expression, increased the rate of N-type inactivation due to a stoichiometric increase in the number of Kv1.4 subunits. PMID:21307345

Imbrici, Paola; D'Adamo, Maria Cristina; Grottesi, Alessandro; Biscarini, Andrea; Pessia, Mauro

2011-06-01

230

Affective Domain  

NSDL National Science Digital Library

The affective domain can significantly enhance, inhibit or even prevent student learning. The affective domain includes factors such as student motivation, attitudes, perceptions and values. Teachers can increase their effectiveness by considering the affective domain in planning courses, delivering lectures and activities, and assessing student learning. This module contains information and resources for incorporating the affective domain into teaching.

231

Photometry Of The Semi-regular Variable Tx Tau  

NASA Astrophysics Data System (ADS)

We report V-band and I-band photometry for the SRA type variable TX Tau. Photometry was obtained using the robotic telescope GORT at the Hume Observatory (NASA funded through Sonoma State University) and the PROMPT robotic telescopes at Cerro Tololo Inter-American Observatory (NSF and NASA funded through the University of North Carolina). Photometry was also obtained using the PI of the Sky optical transient search system at Las Campanas Observatory developed by a consortium of institutions in Poland. Modern periods are determined, the V-band and I-band light curves are compared, and V-I colors are derived. It is possible that the classification for this variable should be reconsidered.

Wyman, Katherine; Spear, G.; McLin, K.; Cominsky, L.; Mankiewicz, L.; Reichart, D.; Ivarsen, K.

2009-12-01

232

Near-IR Photometry of Nova Del 2013  

NASA Astrophysics Data System (ADS)

Subjects: Infra-Red, Nova We report Near-IR photometry of Nova Del 2013 taken with the 0.76-m infrared telescope at the University of Minnesota's O'Brien Observatory (Marine on St. Croix, Minnesota, USA). RIJHKLM photometry were obtained on August 21.17 and 23.13 UT using an AsSi bolometer. Vega (alpha Lyrae) was used as the standard star. Our photometry show: August 21.17 UT: R = 5.1 +/- 0.1, I = 4.6 +/- 0.1, J = 4.6 +/- 0.1, H = 4.1 +/- 0.1, K = 3.9 +/- 0.1, L = 2.7 +/- 0.2, M = +2.2 +/- 0.2.

Cass, C. A.; Carlon, L. R.; Corgan, T. D.; Dykhoff, A. D.; Gehrz, D. R.; Shenoy, P. D.

2013-08-01

233

UBV CCD Photometry of the Open Cluster Berkeley 2  

NASA Astrophysics Data System (ADS)

We present UBV CCD photometry of Be 2, previously unstudied open cluster. Our photometry covers a field of 3'.2 X 3'.8 of the sky centered on the cluster, which is slightly smaller than the cluster diameter estimated to be about 260". We have determined the reddening, distance, age and metallicity of the cluster by fitting the Padova isochrones to the observed stellar distributions in color-magnitude diagram as well as main sequence fitting: E(B-V) = 0.8 +/- 0.05, (m-M)_o = 13.6 +/- 0.1, log(t) = 8.9 +/- 0.1, and Z =0.008. The present photometry shows that Be 2 is a distant open cluster of intermediate age. that it is a distant intermediate-age open cluster.

Ann, Hong Bae; Park, Yoon Ho; Kang, Yong Woo

1998-04-01

234

High-Precision Stellar Photometry with the K2 Mission  

NASA Astrophysics Data System (ADS)

The K2 mission is a repurposed use of the Kepler spacecraft to perform high-precision photometry of selected fields in the ecliptic. We have developed an aperture photometry pipeline for K2 data which performs dynamic automated aperture mask selection, background estimation and subtraction, and positional decorrelation to minimize the effects of spacecraft pointing jitter. Here we describe that pipeline and the photometric precision we are capable of achieving with K2, illustrated by application to Campaign 0 data, and suggest future improvements in our algorithm.

Carboneau, Lindsey; Buzasi, Derek L.; Hessler, Carly; Lezcano, Andy; Preston, Heather L.

2015-01-01

235

Transit and secondary eclipse photometry in the near-infrared  

E-print Network

Near-infrared photometry of transiting extrasolar planets can be of great scientific value. It is however not straightforward to reach the necessary millimagnitude precision. Here we report on our attempts to observe transits and secondary eclipses of several extrasolar planets at 2.2 micron. Best results have been obtained on OGLE-TR-113b using the SOFI near-infrared camera on ESO's New Technology Telescope. Its K-band transit shows a remarkably flat bottom indicating low stellar limb darkening. Secondary eclipse photometry has resulted in a formal 3 sigma detection, but residual systematic effects make this detection rather uncertain.

Ignas Snellen

2007-05-02

236

A Method for Transferring Photoelectric Photometry Data from Apple II+ to IBM PC  

Microsoft Academic Search

A method is presented for transferring photoelectric photometry data files from an Apple II computer to an IBM PC computer in a form which is compatible with the AAVSO Photoelectric Photometry data collection process.

Harry D. Powell; James R. Miller; Kipp Stephenson

1989-01-01

237

A Method for Transferring Photoelectric Photometry Data from Apple II+ to IBM PC  

NASA Astrophysics Data System (ADS)

A method is presented for transferring photoelectric photometry data files from an Apple II computer to an IBM PC computer in a form which is compatible with the AAVSO Photoelectric Photometry data collection process.

Powell, Harry D.; Miller, James R.; Stephenson, Kipp

1989-06-01

238

Retrieval of cirrus properties by Sun photometry: A new perspective on an old issue  

E-print Network

Retrieval of cirrus properties by Sun photometry: A new perspective on an old issue Michal Segal. Ramachandran, J. Redemann, and B. A. Baum (2013), Retrieval of cirrus properties by Sun photometry: A new

Baum, Bryan A.

239

VizieR Online Data Catalog: Radial velocity and photometry for GJ3470 (Bonfils+, 2012)  

NASA Astrophysics Data System (ADS)

The tables contain radial-velocity and photometry time series of GJ3470. Radial velocities were obtained with he HARPS spectrograph. Photometry was obtained with TRAPPIST, EulerCam and NITES telescopes. (5 data files).

Bonfils, X.; Gillon, M.; Udry, S.; Armstrong, D.; Bouchy, F.; Delfosse, X.; Forveille, T.; Fumel, A.; Jehin, E.; Lendl, M.; Lovis, C.; Mayor, M.; McCormac, J.; Neves, V.; Pepe, F.; Perrier, C.; Pollaco, D.; Queloz, D.; Santos, N. C.

2012-11-01

240

Steric factors affecting the discrimination of isomeric and structurally related olefin gases and vapors with a reagent-coated surface acoustic wave sensor.  

PubMed

An investigation of steric factors affecting the olefin-olefin selectivity of a surface acoustic wave (SAW) sensor coated with reagents of the general formula trans-PtCl2(ethylene)-(substituted-pyridine) is described. Detection is based on the mass increase accompanying replacement of ethylene by other gas-phase olefins to form the corresponding olefin-substituted products. Selectivity depends on the relative reaction rates of the different olefins. Within series of structurally similar butenes, acrylates, and aromatic olefins, unusually high selectivity is observed for the less hindered olefins and complete discrimination of isomers is achieved in certain cases. Replacing pyridine by 2-methylpyridine and 2,6-dimethylpyridine in the reagent complex progressively reduces the sensor response. Sensitivities increase with increasing temperature and limits of detection ranging from about 2 to 70 micrograms/L are achieved with modest heating (30-40 degrees C) using a 30-MHz SAW oscillator. Initial results with a 52-MHz sensor shows a 3.4-fold increase in sensitivity compared to the 30-MHz sensor in rough agreement with theory. PMID:1621995

Zellers, E T; Zhang, G Z

1992-06-01

241

The Gaia Mission and the Asteroids. A perspective from space astrometry and photometry  

E-print Network

The Gaia Mission and the Asteroids. A perspective from space astrometry and photometry to perform high accuracy astrometry and photometry. More specifically it will provide physical and dynamical the dynamical model in general. Key words: Gaia ; astrometry ; photometry ; asteroid physical properties ; dy

242

Aperture Photometry in Practice AST337 In-Class Exercise (hand me in before you leave!)  

E-print Network

Aperture Photometry in Practice AST337 In-Class Exercise (hand me in before you leave!) 7 April in pixels, its brightness in ADU ("Object Counts" in "atv aperture photometry" window), its FWHM in pixels FWHM (ie. aperture radius = FWHM)? Part III: PhotVis, an IDL Photometry and Visualization Tool 1. Run

Lowenthal, James D.

243

ON THE AGE AND METALLICITY ESTIMATION OF SPIRAL GALAXIES USING OPTICAL AND NEAR-INFRARED PHOTOMETRY  

E-print Network

ON THE AGE AND METALLICITY ESTIMATION OF SPIRAL GALAXIES USING OPTICAL AND NEAR-INFRARED PHOTOMETRY-infrared photometry show surprisingly orthogonal grids as age and metallicity are varied, and they are coming headinggs: galaxies: abundances -- galaxies: evolution -- galaxies: photometry -- galaxies: spiral

Lee, Hyun-chul

244

Notes for KINGFISH on SPIRE Photometry DRAFT: v8 2013.3.16.759  

E-print Network

Notes for KINGFISH on SPIRE Photometry DRAFT: v8 2013.3.16.759 B. T. Drainea ABSTRACT Some notes on interpretation of SPIRE photometry of extended sources, and recommendations for use by the KINGFISH collaboration photometry to be sometimes confusing: the distinction between beam sizes to use for point sources or extended

Draine, Bruce T.

245

An Improved Technique for the Photometry and Astrometry of Faint Companions  

E-print Network

An Improved Technique for the Photometry and Astrometry of Faint Companions DANIEL BURKE School to differential astrometry and photometry of faint companions in adap- tive optics images. It is based ratio (SR) data (SR 0:5), the differential photometry of a binary star with a m ¼ 4:5 and a separation

Dainty, Chris

246

New Aperture and PSF Photometry QSO 0957+561A,B  

E-print Network

New Aperture and PSF Photometry of QSO 0957+561A,B Application to Time Delay and Microlensing Aperture and PSF Photometry of QSO 0957+561A,B", is distributed under the terms of the Public Library was initiated with the aim of developing a photometry program to reduce the CCD frames. The results were

Ovaldsen, Jan-Erik

247

NOVEL METHODS FOR PREDICTING PHOTOMETRIC REDSHIFTS FROM BROADBAND PHOTOMETRY USING VIRTUAL SENSORS  

E-print Network

NOVEL METHODS FOR PREDICTING PHOTOMETRIC REDSHIFTS FROM BROADBAND PHOTOMETRY USING VIRTUAL SENSORS, and the Two Micron All Sky Survey using two new training-set methods. We utilize the broadband photometry from material: color figures 1. INTRODUCTION Using broadband photometry in multiple filters to estimate

248

Optical properties of boreal forest fire smoke derived from Sun photometry  

E-print Network

Optical properties of boreal forest fire smoke derived from Sun photometry N. T. O'Neill,1 T. F 2001; published 13 June 2002. [1] Aerosol optical properties derived from Sun photometry were: Aerosols (0305); KEYWORDS: aerosols, forest fire smoke, Sun photometry, optics 1. Introduction [2] Smoke

Li, Zhanqing

249

Application Note (A14) A guide to photometry and  

E-print Network

is the science and technology of the measurement of electromagnetic radiant energy. It is more commonly referred radiant energy emitted by the radiating source over the entire optical spectrum (1 nm to 1000 µm, photometry relates to the measurement of radiant energy in the "visible " spectrum as perceived

Johnsen, Sönke

250

Time Series Photometry Data: Standard Access, Standard Formats  

E-print Network

the IAU Archives of Unpublished Observations of Variable Stars, Breger et al., 1990) and in journals (e.g. IBVS or A&A tables at CDS, see Fig. 1). The VO technology for locating data providers is the registry (Plante et al., 2004). A registry should be set up for time series photometry data. A well established VO

Holl, András

251

Effective temperature scale and bolometric corrections from 2MASS photometry  

Microsoft Academic Search

We present a method to determine effective temperatures, angular semi-diameters and bolometric corrections for population I and II FGK type stars based on V and 2MASS IR photometry. Accurate calibration is accomplished by using a sample of solar analogues, whose average temperature is assumed to be equal to the solar effective temperature of 5777 K. By taking into account all

E. Masana; C. Jordi; I. Ribas

2006-01-01

252

Solar type stars: Spectral energy distribution and JHKLM photometry  

NASA Astrophysics Data System (ADS)

Energy distribution data in the range 3400-7500Å obtained by means of the scanner installed at the 60-cm Zeiss reflector and JHKLM photometry provided at the 1.25 m reflector of the Sternberg Institute Crimean Station for eight stars of spectral types G1.5-G3 of V and IV luminosity classes are presented. The accuracy of the spectrophotometric data is about 2% in the range 3400-4000Å, 1% in the range 4000-6000Å and about 1.5-2% in the range 6000-7500Å. The accuracy of JHKLM photometry is 2% in the bands J, H, K and L and 5% in the M band. A comparison of the energy distribution in the spectra of stars with three reliable sets of spectrophotometric data of the Sun is presented. The differences between stellar and solar energy distribution data are at a minimum for BS 6060 and HD 213575. Comparison of stellar JHKLM photometry with synthetic solar photometry in these IR bands was done. The colour indices J - H, J - K, J - L, and J - M of the Sun and solar-type stars were analysed.

Glushneva, I. N.; Borisov, G. V.; Shenavrin, V. I.; Roshchina, I. A.

253

A Laboratory of Photometry and Radiometry of Light Pollution (LPLAB)  

Microsoft Academic Search

We present the Laboratory of Photometry and Radiometry of Light Pollution (LPLAB) that we set up to provide the Light Pollution Science and Technology Institute (ISTIL) of instruments and calibration services to support its scientific and technological research on light pollution and related environmental effects. The laboratory equipments are characterized by low light intensity measurement and calibration capabilities and by

P. Cinzano

2003-01-01

254

Readmefirst_planetary_photometry_data Purpose of this archive  

E-print Network

b ,y photometry of Uranus, Neptune, and Saturn's satellite Titan. While nearly all the data (except_by_season.txt and subsidiary files: Titan_nights.txt Titan_summary.txt Uranus_by_season.txt and subsidiary files: Uranus_nights.txt Uranus_summary.txt Neptune_by_season.txt and subsidiary files: Neptune_nights.txt Neptune _summary

Lockwood, Wes

255

Error analysis of multi-wavelength sun photometry  

Microsoft Academic Search

The error terms involved in precision multi-wavelength sun photometry, as used to study atmospheric aerosols, are analyzed. The error terms treated include instrumental errors, calibration errors, and errors imposed by the atmosphere. It is shown that in order to derive accurate aerosol parameters, one must exercise great care in the photometer calibration. A procedure for accurate calibration is described, based

Glenn E. Shaw

1976-01-01

256

Comet Kohoutek. [proceedings - astronomical photometry/astronomical spectroscopy  

NASA Technical Reports Server (NTRS)

A compilation of scientific observations (workshop) is presented. Topics discussed are: (1) tail form, structure, and evolution; (2) hydroxyl related observations; (3) molecules and atoms in the coma and tail; (4) photometry and radiometry; and (5) spacecraft and ground based observation data. Color photographs are shown.

Gary, G. A. (editor)

1975-01-01

257

Low cost robotic imaging system for high precision photometry  

E-print Network

Low cost robotic imaging system for high precision photometry Olivier Guyon (Subaru Telescope (etendue = 1m telescope, 1deg diam FOV) 10" per pixel photon-noise limited on sky background Low cost, use, observe, choose target) Easy to duplicate and upgrade, low cost ­ scalable to multiple units, higher

Guyon, Olivier

258

SPA, "The Stellar Photometry Assistant", a New Software Package Specializing in High Speed Photometry of White Dwarfs  

NASA Astrophysics Data System (ADS)

SPA, "The Stellar Photometry Assistant", is a new program for photometry reduction and analysis slated for initial release in early 2008. Development was fueled by high speed photometry of white dwarfs, mainly EC20058-5235, a pulsating DB white dwarf. The stability of EC20058-5235's primary mode, along with the relatively short timescales of DB cooling may allow a measurement of dP/dt. EC20058-5235 has 2 companions of comparable magnitude within 5'', which adds significant noise to simple aperture photometry. This, combined with the relatively steep learning curve of IRAF, and IRAF like tools sparked the beginning of SPA. SPA combines powerful, proven, methods with an easy to use interface. Currently SPA is written in MATLAB, but future plans include a cross platform stand alone application. SPA tackles many issues such as auto-tracking jumps in star location and crowded field reduction. SPA will also provide easy to use tools for viewing and manipulating data. The interface is intuitive and is suitable for both amateur and professorial astronomers. SPA is being developed by The University of Delaware in collaboration with the Delaware Asteroseismic Research Center (DARC) and the Mt. Cuba Astronomical Observatory.

Dalessio, James; Kanaan, A.; Provencal, J.

2007-12-01

259

Is increasing industrialization affecting remote ecosystem health in the South Americas? Insights from ocean surface water measurements of As, Sb and Pb from a GEOTRACES transect  

NASA Astrophysics Data System (ADS)

Continued industrial development of the South Americas with increasing atmospheric emission of toxic trace metals has lead to a growing concern about possible effects on pristine ecosystem health. Concentration measurements of trace metals in ocean surface waters in the North Atlantic have successfully revealed the global extent of atmospheric pollution in the Northern Hemisphere during economical growth in the USA and Europe, suggesting a similar approach can be applied to the Southern Hemisphere. To this end, we determined concentrations of lead (Pb), antimony (Sb) and arsenic (As) using voltammetry in surface water samples of the South Atlantic Ocean collected during the third leg of the GEOTRACES West Atlantic Cruise. These elements are volatile and therefore most likely suitable tracer elements of industrial emissions from South America. The samples were not filtered and the solutions were acidified and UV digested. Total concentrations of Pb were detected. Detected As levels correspond to the sum of inorganic species (AsIII + AsV) plus the mono methyl arsenic acid (MMA) while the dimethyl arsenic acid (DMA) is not detected in such conditions. For Sb, detected levels correspond at least to the sum of inorganic fractions (SbIII + SbV). The measured concentrations for Pb varied from 6 to 23 pM. Concentrations were highest at -35° latitude and lowest at -40° and -50° latitude. We found a decreasing trend from about -35° latitude southwards. The average concentrations of As was 20 nM and of Sb 1.2 nM. Arsenic showed a more significant north to south trend than Sb. Arsenic concentration was highest at -23 ° latitude (21 nM) and the lowest at -43 ° latitude (17.7 nM). Antimony concentration was highest at -31 ° latitude (1.5 nM) and lowest at -35 ° latitude (1.0 nM). Our preliminary data suggests that the major industrial centres in Brazil (i.e., Sao Paolo, Rio de Janeiro) and Argentina (i.e., Buenos Aires) affect atmospheric metal fluxes to remote environments. The concentrations, however, are not as high as determined in the Northern Hemisphere, suggesting a less drastic impact. That is also reflected in air quality data from the major cities.

Weiss, Dominik; Salaun, Pascal; Van den Berg, Stan; Bi, Zaoshun

2014-05-01

260

UBVJHKLM photometry and modeling of R Coronae Borealis  

E-print Network

We present the results of UBVJHKLM photometry of R CrB spanning the period from 1976 to 2001. Studies of the optical light curve have shown no evidence of any stable harmonics in the variations of the stellar emission. In the L band we found semi-regular oscillations with the two main periods of ~3.3 yr and 11.9 yr and the full amplitude of ~0.8 mag and ~0.6 mag, respectively. The colors of the warm dust shell (resolved by Ohnaka et al. 2001) are found to be remarkably stable in contrast to its brightness. This indicates that the inner radius is a constant, time-independent characteristic of the dust shell. The observed behavior of the IR light curve is mainly caused by the variation of the optical thickness of the dust shell within the interval \\tau(V)= 0.2-0.4. Anticorrelated changes of the optical brightness (in particular with P ~ 3.3 yr) have not been found. Their absence suggests that the stellar wind of R CrB deviates from spherical symmetry. The light curves suggest that the stellar wind is variable. The variability of the stellar wind and the creation of dust clouds may be caused by some kind of activity on the stellar surface. With some time lag, periods of increased mass-loss cause an increase in the dust formation rate at the inner boundary of the extended dust shell and an increase in its IR brightness. We have derived the following parameters of the dust shell (at mean brightness) by radiative transfer modeling: inner dust shell radius r_in ~ 110 R_*, temperature T_dust(r_in) ~ 860 K, dust density \\rho_dust(r_in) ~ 1.1x10^{-20} g cm^-3, optical depth \\tau(V) ~ 0.32 at 0.55 micron, mean dust formation rate [dM/dt]_dust ~ 3.1x10^-9 M_sun / yr, mass-loss rate [dM/dt]_gas ~ 2.1x10^-7 M_sun / yr, size of the amorphous carbon grains <(~) 0.01 micron, and B-V ~ -0.28.

B. F. Yudin; J. D. Fernie; N. R. Ikhsanov; V. I. Shenavrin; G. Weigelt

2002-09-25

261

A Naturally Occurring Single-Residue Mutation in the Translocator Domain of Neisseria meningitidis NhhA Affects Trimerization, Surface Localization, and Adhesive Capabilities?†  

PubMed Central

Neisseria meningitidis NhhA (Neisseria hia/hsf homologue A) is an oligomeric outer membrane protein belonging to the family of trimeric autotransporter adhesins. NhhA mediates the interaction of N. meningitidis with human epithelial cells and components of the extracellular matrix. The recombinant protein is able to induce bactericidal antibodies and hence has also been considered a potential vaccine candidate. In this study, we analyzed the production of NhhA in a large panel of N. meningitidis strains belonging to different serogroups and clonal complexes. We found that trimeric NhhA was produced at different levels by the various strains tested. In some strains belonging to the clonal complex ST41/44, the protein is detectable only as a monomer. Sequencing of the nhhA gene and generation of complementing strains in different genetic backgrounds have proved that a single mutation (Gly to Asp) in the translocator domain affected both trimerization and surface localization of NhhA. In vitro infection assays showed that this mutation impairs meningococcal NhhA-mediated adhesion, suggesting that strains carrying the mutation may rely on different strategies or molecules to mediate interaction with host cells. Finally, we demonstrated that N. meningitidis ST41/44 strains producing the mutated form did not induce killing mediated by NhhA-specific bactericidal antibodies. Our data help to elucidate the secretion mechanisms of trimeric autotransporters and to understand the contribution of NhhA in the evolutionary process of host-Neisseria interactions. Also, they might have important implications for the evaluation of NhhA as a vaccine candidate. PMID:21844231

Echenique-Rivera, Hebert; Brunelli, Brunella; Scarselli, Maria; Taddei, Anna Rita; Pizza, Mariagrazia; Aricò, Beatrice; Serruto, Davide

2011-01-01

262

How surface fire in Siberian Scots pine forests affects soil organic carbon in the forest floor: Stocks, molecular structure, and conversion to black carbon (charcoal)  

NASA Astrophysics Data System (ADS)

In boreal forests, fire is a frequent disturbance and converts soil organic carbon (OC) to more degradation-resistant aromatic carbon, i.e., black carbon (BC) which might act as a long-term atmospheric-carbon sink. Little is known on the effects of fires on boreal soil OC stocks and molecular composition. We studied how a surface fire affected the composition of the forest floor of Siberian Scots pine forests by comparing the bulk elemental composition, molecular structure (13C-MAS NMR), and the aromatic carbon fraction (BC and potentially interfering constituents like tannins) of unburned and burned forest floor. Fire reduced the mass of the forest floor by 60%, stocks of inorganic elements (Si, Al, Fe, K, Ca, Na, Mg, Mn) by 30-50%, and of OC, nitrogen, and sulfur by 40-50%. In contrast to typical findings from temperate forests, unburned OC consisted mainly of (di-)O-alkyl (polysaccharides) and few aromatic structures, probably due to dominant input of lichen biomass. Fire converted OC into alkyl and aromatic structures, the latter consisting of heterocyclic macromolecules and small clusters of condensed carbon. The small cluster size explained the small BC concentrations determined using a degradative molecular marker method. Fire increased BC stocks (16 g kg-1 OC) by 40% which translates into a net-conversion rate of 0.7% (0.35% of net primary production) unburned OC to BC. Here, however, BC was not a major fraction of soil OC pool in unburned or burned forest floor, either due to rapid in situ degradation or relocation.

Czimczik, Claudia I.; Preston, Caroline M.; Schmidt, Michael W. I.; Schulze, Ernst-Detlef

2003-03-01

263

Galileo Photometry of Asteroid 243 Ida  

Microsoft Academic Search

Galileo imaging observations over phase angles 19.5° to 109.8° are combined with near-opposition Earth-based data to derive the photometric properties of Ida. To first order these properties are uniform over the surface and well modeled at ? = 0.55 ?m by Hapke parameters ?0= 0.22,h= 0.020,B0= 1.5,g= ?0.33, and ? = 18° with corresponding geometric albedop= 0.21±0.030.01and Bond albedoAB= 0.081±0.0170.008.

P. Helfenstein; J. Veverka; P. C. Thomas; D. P. Simonelli; K. Klaasen; T. V. Johnson; F. Fanale; J. Granahan; A. S. McEwen; M. Belton; C. Chapman

1996-01-01

264

High-speed multicolour photometry with CMOS cameras  

NASA Astrophysics Data System (ADS)

We present the results of testing the commercial digital camera Nikon D90 with a CMOS sensor for high-speed photometry with a small telescope Celestron 11'' at the Peak Terskol Observatory. CMOS sensor allows to perform photometry in 3 filters simultaneously that gives a great advantage compared with monochrome CCD detectors. The Bayer BGR colour system of CMOS sensors is close to the Johnson BVR system. The results of testing show that one can carry out photometric measurements with CMOS cameras for stars with the V-magnitude up to ?14^{m} with the precision of 0.01^{m}. Stars with the V-magnitude up to ˜10 can be shot at 24 frames per second in the video mode.

Pokhvala, S. M.; Zhilyaev, B. E.; Reshetnyk, V. M.

2012-11-01

265

Preliminary results from VLT (FORS1) photometry of NGC 6397  

E-print Network

We present VLT (FORS1) photometry of the lower main sequence (MS) of the Galactic Globular Cluster (GGC) NGC 6397, for stars located in 2 fields extending from a region near the cluster center out to ~ 10'. The obtained CMD shows a narrow MS extending down to V ~ 27 (figure c), much deeper than any previous ground based study and comparable with previous HST photometry (Cool et al. 1996). The comparison between observed MS Luminosity Functions (LFs) derived for 2 annuli at different radial distance from the center of the cluster shows a clear-cut correlation between their slope before reaching the turn-over, and the radial position of the observed fields inside the cluster area: the LFs become flatter with decreasing radius, a trend that is consistent with the interpretation of NGC 6397 as a dynamically relaxed system.

Andreuzzi, G; Marconi, G; Alcaino, G; Alvarado, F L; Buonanno, R

2002-01-01

266

Absolute stellar photometry on moderate-resolution FPA images  

USGS Publications Warehouse

An extensive database of star (and Moon) images has been collected by the ground-based RObotic Lunar Observatory (ROLO) as part of the US Geological Survey program for lunar calibration. The stellar data are used to derive nightly atmospheric corrections for the observations from extinction measurements, and absolute calibration of the ROLO sensors is based on observations of Vega and published reference flux and spectrum data. The ROLO telescopes were designed for imaging the Moon at moderate resolution, thus imposing some limitations for the stellar photometry. Attaining accurate stellar photometry with the ROLO image data has required development of specialized processing techniques. A key consideration is consistency in discriminating the star core signal from the off-axis point spread function. The analysis and processing methods applied to the ROLO stellar image database are described. ?? 2009 BIPM and IOP Publishing Ltd.

Stone, T.C.

2009-01-01

267

Optical Photometry of V404 Cyg (=GS2023+338)  

NASA Astrophysics Data System (ADS)

In response to the request by Hjellming et al. in ATEL #54, Rose Finn (Steward Observatory/U. Arizona) obtained for us two R-band CCD images of V404 Cyg (=GS2023+338) on 2000 Mar 3.52 UT with the Steward Observatory Bok 2.3-m telescope and direct CCD (scale = 0.3 arcsec/pixel, airmass = 1.8, seeing = 1.7 arcsec FWHM). Photometry of V404 Cyg was obtained with respect to the comparison stars C1, C4, and C5 of Udalski and Kaluzny (1991, PASP, 103, 198), Casares et al. (1993, MNRAS, 265, 834), and our own photometry of C1 (R = 12.39).

Wagner, R. M.; Shrader, C. R.; Starrfield, S. G.

2000-03-01

268

The Spitzer Local Volume Legacy (LVL) global optical photometry  

NASA Astrophysics Data System (ADS)

We present the global optical photometry of 246 galaxies in the Local Volume Legacy (LVL) survey. The full volume-limited sample consists of 258 nearby (D < 11 Mpc) galaxies whose absolute B-band magnitude span a range of -9.6 < MB < -20.7 mag. A composite optical (UBVR) data set is constructed from observed UBVR and Sloan Digital Sky Survey ugriz imaging, where the ugriz magnitudes are transformed into UBVR. We present photometry within three galaxy apertures defined at UV, optical, and IR wavelengths. Flux comparisons between these apertures reveal that the traditional optical R25 galaxy apertures do not fully encompass extended sources. Using the larger IR apertures, we find colour-colour relationships where later type spiral and irregular galaxies tend to be bluer than earlier type galaxies. These data provide the missing optical emission from which future LVL studies can construct the full panchromatic (UV-optical-IR) spectral energy distributions.

Cook, David O.; Dale, Daniel A.; Johnson, Benjamin D.; Van Zee, Liese; Lee, Janice C.; Kennicutt, Robert C.; Calzetti, Daniela; Staudaher, Shawn M.; Engelbracht, Charles W.

2014-11-01

269

Copernicus spectra and infrared photometry of 42 Orionis  

NASA Technical Reports Server (NTRS)

The Orion sword star 42 Ori is embedded in a nebula north of and separated from the Orion nebula. The B1 V star is probably normal. Other members of the multiple remain poorly defined, and the nebula may exhibit some peculiarities that may depend on them. Copernicus ultraviolet spectra of the star are described here, especially in the form of tables of wavelength identifications. The properties of the interstellar material in the line of sight are also discussed. Infrared photometry is presented which suggests that the ratio of total to selective extinction ranges from 3 to 3.5 for the interstellar matter in the direction of 42 Ori. The IR photometry provides no evidence for companion stellar or circumstellar components.

Johnson, H. M.; Snow, T. P., Jr.; Gehrz, R. D.; Hackwell, J. A.

1977-01-01

270

Ultraviolet photometry of OB associations in M31  

NASA Technical Reports Server (NTRS)

The study obtains near-UV and FUV magnitudes for 76 massive stars in 24 OB associations in the central and southern portions of M31 from images obtained by the Ultraviolet Imaging Telescope (UIT) during the Astro 1 spacelab mission. A comparison is made with the previous UIT photometry of 30 stars in the giant association NGC 206. Extinctions are estimated from the relation between E(B - V) and the distance from the center of M31 derived by Hodge and Lee (1988) from topical CCD stellar photometry. From evolutionary models, lower limits to the maximum stellar mass are estimated at about 60-100 solar masses in NGC 206, A29, A61, A63, A130, and A132. For other associations, the limits are in the range of about 20-55 solar masses.

Hill, Jesse K.; Isensee, Joan E.; Bohlin, Ralph C.; O'Connell, Robert W.; Roberts, Morton S.; Smith, Andrew M.; Stecher, Theodore P.

1993-01-01

271

CCD time-resolved photometry of faint cataclysmic variables. IV  

Microsoft Academic Search

Time-resolved CCD photometry in V, B, and the near-IR has been obtained, with average time-series length of 3 hours, for 15 certified or candidate cataclysmic-variable faint stars. Orbital periods are found in three of the stars, and nine others are noted to exhibit evidence leading toward confirmation of cataclysmic-variable status. The characteristics of PG 0917+342 and PG 2240+193 are as

Steve B. Howell; DANUTA Dobrzycka; PAULA Szkody; Tobias J. Kreidl

1991-01-01

272

CCD time-resolved photometry of faint cataclysmic variables. IV  

NASA Technical Reports Server (NTRS)

Time-resolved CCD photometry in V, B, and the near-IR has been obtained, with average time-series length of 3 hours, for 15 certified or candidate cataclysmic-variable faint stars. Orbital periods are found in three of the stars, and nine others are noted to exhibit evidence leading toward confirmation of cataclysmic-variable status. The characteristics of PG 0917+342 and PG 2240+193 are as yet unclear.

Howell, Steve B.; Dobrzycka, Danuta; Szkody, Paula; Kreidl, Tobias J.

1991-01-01

273

Astrometry and Photometry for Cool Dwarfs and Brown Dwarfs  

Microsoft Academic Search

Trigonometric parallax determinations are presented for 28 late-type dwarfs and brown dwarfs, including eight M dwarfs with spectral types between M7 and M9.5, 17 L dwarfs with spectral types between L0 and L8, and three T dwarfs. Broadband photometry at CCD wavelengths (VRIz*) and\\/or near-IR wavelengths (JHK) is presented for these objects and for 24 additional late-type dwarfs. Supplemented with

Conard C. Dahn; Hugh C. Harris; Frederick J. Vrba; Harry H. Guetter; Blaise Canzian; Arne A. Henden; Stephen E. Levine; Christian B. Luginbuhl; Alice K. B. Monet; David G. Monet; Jeffrey R. Pier; Ronald C. Stone; Richard L. Walker; Adam J. Burgasser; John E. Gizis; J. Davy Kirkpatrick; James Liebert; I. Neill Reid

2002-01-01

274

Accuracy of Star Cluster Parameters from Integrated UBVRI Photometry  

E-print Network

We study the capability of the UBVRI photometric system to quantify star clusters in terms of age, metallicity, and color excess by their integrated photometry. The well known age-metallicity-extinction degeneracy was analyzed for various parameter combinations, assuming different levels of photometric accuracy. We conclude that the UBVRI photometric system enables us to estimate star cluster parameters over a wide range, if the overall photometric accuracy is better than ~0.03 mag.

D. Narbutis; A. Bridzius; R. Stonkute; V. Vansevicius

2007-12-23

275

UBVJHKLM photometry and modeling of R Coronae Borealis  

Microsoft Academic Search

We present the results of UBVJHKLM photometry of R CrB spanning the period\\u000afrom 1976 to 2001. Studies of the optical light curve have shown no evidence of\\u000aany stable harmonics in the variations of the stellar emission. In the L band\\u000awe found semi-regular oscillations with the two main periods of ~3.3 yr and\\u000a11.9 yr and the full

B. F. Yudin; J. D. Fernie; N. R. Ikhsanov; V. I. Shenavrin; G. Weigelt

2002-01-01

276

Multicolor Photometry of the Uranus Irregular Satellites Sycorax and Caliban  

E-print Network

We report on accurate BVRI photometry for the two Uranus irregular satellites Sycorax and Caliban. We derive colours, showing that Sycorax is bluer than Caliban. Our data allows us to detect a significant variability in the Caliban's light-curve, which suggests an estimated period of about 3 hours. Despite it is the brighter of the two bodies, Sycorax does not display a strong statistically significant variability. However our data seem to suggest a period of about 4 hours

Michele Maris; Giovanni Carraro; Gabriele Cremonese; Marco Fulle

2001-01-27

277

Blue-light imagery and photometry of sprites  

Microsoft Academic Search

We have obtained blue (350–475 nm) video images and simultaneous high-time resolution narrow-band blue (415–435 nm) photometry records of four sprite events. The brightest blue images show a sustained tendril geometry and a nearly constant intensity of emission over the entire vertical extent of the sprite (from 35–90 km altitude). Photometer light curves display an exponential decay with a 0.3

David M. Suszcynsky; Robert Roussel-Dupré; Walter A. Lyons; Russell A. Armstrong

1998-01-01

278

MATPHOT algorithm for digital point spread function CCD stellar photometry  

NASA Astrophysics Data System (ADS)

The MATPHOT algorithm for digital Point Spread Function (PSF) CCD stellar photometry is described. A theoretical photometric and astrometric performance model is presented for PSF-fitting stellar photometry. MATPHOT uses a digital representation of the sampled PSF consisting of a numerical table (e.g., a matrix or a FITS image) instead of an analytical function. MATPHOT achieves accurate stellar photometry with under-sampled CCD observations with super-sampled PSFs. MATPHOT currently locates a PSF within the observational model using a 21-pixel-wide damped sinc interpolation function. Position partial derivatives of the observational model are determined using numerical differentiation techniques. Results of MATPHOT-based design studies of the optical performance of the Next Generation Space Telescope are presented; observations of bright stars analyzed with the MATPHOT algorithm can yield millimag photometric errors with millipixel relative astrometric errors -- or better -- if observed with a perfect detector. Plans for the future development of a parallel-processing version of the MATPHOT algorithm using Beowulf clusters are described. All of the C source code and documentation for MATPHOT is freely available as part of the MXTOOLS package for IRAF (http://www.noao.edu/staff/mighell/mxtools). This work is supported by a grant from NASA's Office of Space Science.

Mighell, Kenneth J.

2002-12-01

279

Pushing the precision limit of ground-based eclipse photometry  

E-print Network

Until recently, it was considered by many that ground-based photometry could not reach the high cadence sub-mmag regime because of the presence of the atmosphere. Indeed, high frequency atmospheric noises (mainly scintillation) limit the precision that high SNR photometry can reach within small time bins. If one is ready to damage the sampling of his photometric time-series, binning the data (or using longer exposures) allows to get better errors, but the obtained precision will be finally limited by low frequency noises. To observe several times the same planetary eclipse and to fold the photometry with the orbital period is thus generally considered as the only option to get very well sampled and precise eclipse light curve from the ground. Nevertheless, we show here that reaching the sub-mmag sub-min regime for one eclipse is possible with a ground-based instrument. This has important implications for transiting planets characterization, secondary eclipses measurement and small planets detection from the ground.

M. Gillon; D. R. Anderson; B. -O. Demory; D. M. Wilson; C. Hellier; D. Queloz; C. Waelkens

2008-06-30

280

Empirical color transformations between SDSS photometry and other photometric systems  

NASA Astrophysics Data System (ADS)

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

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

2006-12-01

281

Testing theoretical models of subdwarf B stars using multicolor photometry  

NASA Astrophysics Data System (ADS)

Pulsating stars allow a direct investigation of their structure and evolutionary history from the evaluation of pulsation modes. However, the observed pulsation frequencies must first be identified with spherical harmonics (modes). For subdwarfs B (sdB) stars, such identifications using white light photometry currently have significant limitations. We intend to use multicolor photometry to identify pulsation modes and constrain structure models. We propose to observe two pulsating sdB stars: PG1047+003 and PG1325+101. The first object will be observed as part of a multisite campaign (along with WHT and PROMPT). With multicolor photometry, we will use perturbative atmospheric models (BRUCE/KYLIE) to identify the pulsation frequencies. This is part of our NSF grant to obtain seismic tools to test structure and evolution models; constraining stellar parameters including total mass, envelope mass, internal composition discontinuities and internal rotation. In January we have been allocated 7 night on the 2.1 m to collect multicolor data and on the 4 m for time-resolved spectroscopy on J06398+5156, another promising pulsating subdwarf B star for our purposes.

Reed, Mike; Baran, Andrzej; O'Toole, Simon; Telting, John; Shadwick, Marcus; Ostensen, Roy

2012-02-01

282

M2K Planet Search: Spectroscopic Screening and Transit Photometry  

NASA Astrophysics Data System (ADS)

The M2K project is a search for planets orbiting nearby early M and late K dwarf drawn from the SUPERBLINK catalog. M and K dwarfs are highly attractive targets for finding low-mass and habitable planets because (1) close-in planets are more likely to orbit within their habitable zone, (2) planets orbiting them induce a larger Doppler signal and have deeper transits than similar planets around F, G, and early K type stars, (3) planet formation models predict they hold an abundance of super-Earth sized planets, and (4) they represent the vast majority of the stars close enough for direct imaging techniques. In spite of this, only 10% of late K and early M dwarfs are being monitored by current Doppler surveys. As part of the M2K project we have obtained low-resolution spectra for more than 2000 of our sample of 10,000 M and K dwarfs. We vet our sample by screening these stars for high metallicity and low chromospheric activity. We search for transits on targets showing high RMS Doppler signal and photometry candidates provided by SuperWASP project. By using "snapshot” photometry have been able to achieve sub-millimag photometry on numerous transit targets in the same night. With further follow-up observations we will be able to detect planets smaller than 10 Earth masses.

Mann, Andrew; Gaidos, E.; Fischer, D.; Lepine, S.

2010-10-01

283

Galileo photometry of asteroid 243 Ida  

USGS Publications Warehouse

Galileo imaging observations over phase angles 19.5?? to 109.8?? are combined with near-opposition Earth-based data to derive the photometric properties of Ida. To first order these properties are uniform over the surface and well modeled at ?? = 0.55 ??m by Hapke parameters ????0 = 0.22, h = 0.020, B0 = 1.5, g = -0.33, and ?? = 18?? with corresponding geometric albedo p = 0.21??0.030.01 and Bond albedo AB = 0.081??0.0170.008. Ida's photometric properties are more similar to those of "average S-asteroids" (P. Helfenstein and J. Veverka 1989, Asteroids II, Univ. of Arizona Press, Tucson) than are those of 951 Gaspra. Two primary color units are identified on Ida: Terrain A exhibits a spectrum with relatively shallower 1-??m absorption and a relatively steeper red spectral slope than average Ida, while Terrain B has a deeper 1-??m absorption and a less steep red slope. The average photometric properties of Ida and Terrain A are similar while those of Terrain B differ mostly in having a slightly higher value of ????0 (0.22 versus 0.21), suggesting that Terrain B consists of slightly brighter, more transparent regolith particles. Galileo observations of Ida's satellite Dactyl over phase angles 19.5?? to 47.6?? suggest photometric characteristics similar to those of Ida, the major difference being Dactyl's slightly lower albedo (0.20 compared to 0.21). ?? 1990 Academic Press, Inc.

Helfenstein, P.; Veverka, J.; Thomas, P.C.; Simonelli, D.P.; Klaasen, K.; Johnson, T.V.; Fanale, F.; Granahan, J.; McEwen, A.S.; Belton, M.; Chapman, C.

1996-01-01

284

IR-array photometry of Galactic globular clusters - II. JK photometry of 47 TUC  

NASA Astrophysics Data System (ADS)

We present near-infrared J and K photometry obtained with IRAC-2 at the European Southern Observatory for a sample of 3512 giant (red giant and asymptotic giant branch) and horizontal branch stars in the 4x4 arcmin^2 central region of the Galactic globular cluster 47 Tuc (NGC 104). Optical V data for 2345 stars in common from Bica, Ortolani & Barbuy are also used to study very populous and complete colour-magnitude diagrams down to K<~15 (~2 mag fainter than the HB). The main results are as follows. (1) The brightest non-variable star (K=6.75, V-K=5.89, J-K=0.98) yields a statistically significant estimate of the RGB tip and a good match with the He-flash luminosity predicted by the Straniero & Chieffi theoretical evolutionary models, at M_bol=3.74 for metallicity [Fe/H]=-0.7. Such a metallicity value, independently deduced from the `photometric' CMD indicators, is in full agreement with previous `spectroscopic' determinations and yields an excellent fit (to within ~50K) between the observed RGB ridge line and the same theoretical tracks at the level of the so-called RGB bump. The RGB bump, clearly detected at K=12.05+/-0.05, is, however, ~0.4 mag fainter than predicted by current models, as previously found by Fusi Pecci et al. All of the brightest stars brighter than the predicted RGB tip are long-period variables and presumably belong to the asymptotic giant branch. (2) At variance with previous claims, no statistically significant radial gradient is detected either in colour or in stellar population within the central area (r<1 arcmin). The cluster centre of gravity differs by about 5 arcsec from the centre of K luminosity, and by a similar quantity from the centre of V luminosity, and the values here determined are in agreement with those presented by Calzetti et al. (3) The population ratios of the various branches are consistent with the predictions of the `standard and canonical' models and, via the R-method, yield an estimate of the primordial He abundance of Y=0.22+/-0.02. (4) The heliocentric distance estimated using various standard candles and adopting K_HB=11.95+/-0.05, V_HB=14.10+/-0.10, E(B-V)=0.04 and [Fe/H]=-0.7 turns out to be 4.6 kpc.

Montegriffo, P.; Ferraro, F. R.; Fusi Pecci, F.; Origlia, L.

1995-10-01

285

Determining Rotational Periods with Relative Photometry: V836 Tauri & BP Tauri  

NASA Astrophysics Data System (ADS)

Rotational periods for the T Tauri stars V836 Tau and BP Tau were determined using relative photometry in the B, V, and R filters. A rotational period of 7.0 days for V836 Tau was found and is consistent with other published periods. This variation in flux is likely caused by a combination of hot and cool spots on the star's surface. Initial analysis of one week's worth of data for the young star BP Tau revealed a rotational period of approximately 5.6 days; with the inclusion of all our data sets taken over 4 years we will obtain a more robust result. This research is part of a larger program with the goal of searching for exoplanets around stars in the Taurus-Auriga association. By comparing photometric rotation periods with radial velocity periods, variability caused by exoplanets rather than star spots can be identified. This research was supported by NSF grant number AST-1004107.

DeRoo, Cailah; Prato, L.; Skiff, B.; Crockett, C.; Mahmud, N.; Johns-Krull, C.

2011-01-01

286

A 3D extinction map of the northern Galactic plane based on IPHAS photometry  

NASA Astrophysics Data System (ADS)

We present a 3D map of extinction in the northern Galactic plane derived using photometry from the INT/WFC Photometric H? Survey of the northern Galactic plane. The map has fine angular ( ˜ 10 arcmin) and distance (100 pc) sampling allied to a significant depth (?5 kpc). We construct the map using a method based on a hierarchical Bayesian model described in a previous article by Sale. In addition to mean extinction, we also measure differential extinction, which arises from the fractal nature of the interstellar medium, and show that it will be the dominant source of uncertainty in estimates of extinction to some arbitrary position. The method applied also furnishes us with photometric estimates of the distance, extinction, effective temperature, surface gravity, and mass for ˜38 million stars. Both the extinction map and the catalogue of stellar parameters are made publicly available via http://www.iphas.org/extinction.

Sale, S. E.; Drew, J. E.; Barentsen, G.; Farnhill, H. J.; Raddi, R.; Barlow, M. J.; Eislöffel, J.; Vink, J. S.; Rodríguez-Gil, P.; Wright, N. J.

2014-10-01

287

CCD photometry of the BL Lacertae object 1400+162 and the associated group of galaxies  

NASA Technical Reports Server (NTRS)

Surface photometry of the BL Lacertae object 1400+162 and an apparently associated group of galaxies has been obtained using a CCD camera. Observations were made in V, broad bandpasses centered on 0.75 micron and 1.0 micron and with no filter. The colors of all but two of the galaxies suggest they are ellipticals, with the colors of the remaining two considerably bluer. Analysis using a method described by Schechter and Press (1976) suggests the group is a small one. The group may be similar to the one associated with the quasar 3C 273. The spectral index of the BL Lac object is 1.49 + or 0.21. This value allows, but does not require, the presence of an underlying elliptical galaxy. The radio-optical and optical-X-ray indices for 1400+162 are similar to values found for quasars.

Weistrop, D.; Reitsema, H. J.; Smith, B. A.; Shaffer, D. B.

1983-01-01

288

STAR FORMATION IN THE OUTER DISKS OF SPIRAL GALAXIES: ULTRAVIOLET AND H{alpha} PHOTOMETRY  

SciTech Connect

We present an analysis of ultradeep UV and H{alpha} imaging of five nearby spiral galaxies to study the recent star formation in the outer disk. Using azimuthally averaged ellipse photometry as well as aperture photometry of individual young stellar complexes, we measure how star formation rates (SFRs) and UV and H{alpha} colors vary with radius. We detect azimuthally averaged UV flux to {approx}1.2-1.4 R{sub 25} in most galaxies; at the edge of the detected UV disk, the surface brightnesses are 28-29 mag arcsec{sup -2}, corresponding to SFR surface densities of {approx}3 Multiplication-Sign 10{sup -4} M{sub Sun} yr{sup -1} kpc{sup -2}. Additionally, we detect between 120 and 410 young stellar complexes per galaxy, with a significant number of detections out to {approx}1.5 R{sub 25}. We measure radial FUV-NUV profiles, and find that the dispersion in the UV colors of individual young stellar complexes increases with radius. We investigate how radial variations in the frequency of star formation episodes can create color gradients and increasing dispersion in the UV colors of star-forming regions, like those observed in our study. Specifically, we use recently published, high spatial and temporal resolution measurements of {Sigma}{sub SFR} throughout the disk of M33 to estimate the frequency of star formation episodes throughout the disk of a typical spiral galaxy. We use stellar synthesis models of these star formation histories (SFHs) to measure the variations in UV colors and find that we can replicate large dispersions in UV colors based on episodic SFHs.

Barnes, Kate L.; Van Zee, Liese [Department of Astronomy, Indiana University, Bloomington, IN 47405 (United States); Skillman, Evan D., E-mail: barneskl@astro.indiana.edu, E-mail: vanzee@astro.indiana.edu, E-mail: skillman@astro.umn.edu [Department of Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)

2011-12-20

289

The effects of ultraviolet photometry and binary interactions on photometric redshift and galaxy morphology  

NASA Astrophysics Data System (ADS)

Using the HYPERZ code and a template spectral library, which consists of four observed galaxy spectra from Coleman, Wu & Weedman (CWW) and eight spectral families built with evolutionary population synthesis models, we present photometric redshift (photo-z) estimates for a spectroscopic sample of 6531 galaxies. Spectroscopic redshifts are also available, and are selected from the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) and the Galaxy Evolution Explorer (GALEX) Data Release 4 (DR4). There are also morphologies for a morphological sample of 1502 bright galaxies, which are from the catalogue of Fukugita et al., and these are also matched with SDSS DR7 and GALEX DR4. We find that the inclusion of FUV or NUV, or both, decreases the number of catastrophic identifications (|zphot - zspec | > 1.0). If catastrophic identifications are removed, the inclusion of both FUV and NUV photometry mainly increases the number of non-catastrophic identifications in the low-redshift, and fainter r-magnitude regions. The inclusion of binary interactions mainly increases the number of non-catastrophic identifications and decreases the deviations in the region when only using optical photometry. Based on the morphological galaxy sample, we find that the inclusion of ultraviolet (UV) photometry decreases and increases the probability that early types are classified as burst and E types, respectively. This increases the probability that late types are classified as CWW-Sbc and CWW-Scd types. If catastrophic identifications are excluded, the inclusion of UV data mainly increases the identifications of late types in all redshift, bluer g-r and r >~ 14 regions. Moreover, binary interactions mainly affect the determinations of E and S0 types. In comparison, we find that the reliability and completeness for early- and late-type selection by the HYPERZ code are less than those by the concentration index C = 2.6, the profile likelihood Pexp - PdeV = 0 and colour criteria. Moreover, we find that and discriminators can be used as morphology selection indicators. These two criteria have comparable reliability and completeness for selecting early- and late-type galaxies to C = 2.6 criterion and higher completeness for early-type selection than the criterion.

Zhang, Fenghui; Han, Zhanwen; Li, Lifang; Shan, Hongguang; Zhang, Yu

2010-10-01

290

Extinctions and distances of dark clouds from UGRIJHK photometry of red clump giants: the North America and Pelican nebulae complex  

E-print Network

A possibility of applying 2MASS J, H, Ks, IPHAS r, i and MegaCam u, g photometry of red giants for determining distances to dark clouds is investigated. Red clump giants with a small admixture of G5-K1 and M2-M3 stars of the giant branch can be isolated and used in determining distances to separate clouds or spiral arms. The method is applied to an area of the North America and Pelican nebulae complex. Interstellar extinctions of background red giants can be also used for mapping dust surface density in the cloud.

Straizys, V

2009-01-01

291

Multicolor Photometry of the Merging Galaxy Cluster A2319: Dynamics and Star Formation Properties  

NASA Astrophysics Data System (ADS)

Asymmetric X-ray emission and a powerful cluster-scale radio halo indicate that A2319 is a merging cluster of galaxies. This paper presents our multicolor photometry for A2319 with 15 optical intermediate filters in the Beijing-Arizona-Taiwan-Connecticut (BATC) system. There are 142 galaxies with known spectroscopic redshifts within the viewing field of 58' × 58' centered on this rich cluster, including 128 member galaxies (called sample I). A large velocity dispersion in the rest frame, 1622^{+91}_{-70} km s-1, suggests merger dynamics in A2319. The contour map of projected density and localized velocity structure confirm the so-called A2319B substructure, at ~10' northwest to the main concentration A2319A. The spectral energy distributions (SEDs) of more than 30,000 sources are obtained in our BATC photometry down to V ~ 20 mag. A u-band (~3551 Å) image with better seeing and spatial resolution, obtained with the Bok 2.3 m telescope at Kitt Peak, is taken to make star-galaxy separation and distinguish the overlapping contamination in the BATC aperture photometry. With color-color diagrams and photometric redshift technique, 233 galaxies brighter than h BATC = 19.0 are newly selected as member candidates after an exclusion of false candidates with contaminated BATC SEDs by eyeball-checking the u-band Bok image. The early-type galaxies are found to follow a tight color-magnitude correlation. Based on sample I and the enlarged sample of member galaxies (called sample II), subcluster A2319B is confirmed. The star formation properties of cluster galaxies are derived with the evolutionary synthesis model, PEGASE, assuming a Salpeter initial mass function and an exponentially decreasing star formation rate (SFR). A strong environmental effect on star formation histories is found in the manner that galaxies in the sparse regions have various star formation histories, while galaxies in the dense regions are found to have shorter SFR time scales, older stellar ages, and higher interstellar medium metallicities. For the merging cluster A2319, local surface density is a better environmental indicator rather than the cluster-centric distance. Compared with the well-relaxed cluster A2589, a higher fraction of star-forming galaxies is found in A2319, indicating that the galaxy-scale turbulence stimulated by the subcluster merger might have played a role in triggering the star formation activity.

Yan, Peng-Fei; Yuan, Qi-Rong; Zhang, Li; Zhou, Xu

2014-05-01

292

Photometry and spectroscopy in the open cluster Alpha Persei, 2  

NASA Technical Reports Server (NTRS)

Results from a combination of new spectroscopic and photometric observations in the lower main-sequence and pre-main sequence of the open cluster alpha Persei are presented. New echelle spectroscopy has provided radial and rotational velocity information for thirteen candidate members, three of which are nonmembers based on radial velocity, absence of a Li 6707A feature, and absence of H-alpha emission. A set of revised rotational velocity estimates for several slowly rotating candidates identified earlier is given, yielding rotational velocities as low as 7 km/s for two apparent cluster members. VRI photometry for several pre-main sequence members is given; the new (V,V-I(sub K)) photometry yields a more clearly defined pre-main sequence. A list of approximately 43 new faint candidate members based on the (V,V-I(sub K)) CCD photometry is presented in an effort to identify additional cluster members at very low masses. Low-dispersion spectra obtained for several of these candidates provide in some cases supporting evidence for cluster membership. The single brown dwarf candidate in this cluster is for the first time placed in a color-magnitude diagram with other cluster members, providing a better means for establishing its true status. Stars from among the list of new photometric candidates may provide the means for establishing a sequence of cluster members down to very faint magnitudes (V approximately 21) and consequently very low masses. New coordinate determinations for previous candidate members and finding charts for the new photometric candidates are provided in appendices.

Prosser, Charles F.

1993-01-01

293

Identifying Subluminous M Stars Using Three Color Photometry  

NASA Astrophysics Data System (ADS)

Subdwarf stars are stars that appear below the main sequence in a color-magnitude diagram for the most common stars which make up the disk of our galaxy. The present criteria for identifying red subdwarfs vary based on the observational data. Typically, stars have been classified as subdwarfs if they were faint with high proper motions. It is also known that subdwarfs are metal poor and can be identified by visual inspection of their spectra as well. By examining a red star’s relative TiO5 and CaH abundances in digital spectra, it can be classified as subdwarf. Such classification requires the acquisition and analysis of digital spectra which is very time consuming. This project attempted to determine if these stars can be objectively identified using three-color photometry. The three-color photometry compares broad band R and I colors and intermediate-band CaH observations. This photometry, developed at Ball State University, has been shown to be effective and efficient in luminosity classification (distinguishing between giant and dwarf stars) and in estimating distances to red dwarf stars. Observations of red dwarfs and subdwarfs made using the 0.9-m telescope of the Southeastern Association for Research in Astronomy (SARA) showed that stars in the color range 0.9 < R-I < 1.4 can be identified as subluminous using their position in the (R-CaH) - (R-I) two-color diagram. This information can be very helpful in identifying subdwarf stars in photometric surveys for red dwarf stars and in reducing systematic errors in their photometric parallaxes.

Robertson, Thomas H.; Thompson, S. K.; Thompson, D. L.

2013-06-01

294

Surface adsorption, intracellular accumulation and compartmentalization of Pb(II) in batch-operated lagoons with Salvinia minima as affected by environmental conditions, EDTA and nutrients  

Microsoft Academic Search

The effects of environmental factors and nutrients on the various possible removal mechanisms (surface adsorption, intracellular\\u000a accumulation and precipitation to sediments) and partitioning of lead among various compartments (plant biomass, water column\\u000a and sediments) in Salvinia minima batch-operated lagoons, were evaluated. Surface adsorption was found to be the predominant mechanism for Pb(II) removal under\\u000a all environmental conditions tested in the

Eugenia J. Olguín; Gloria Sánchez-Galván; Teresa Pérez-Pérez; Arith Pérez-Orozco

2005-01-01

295

UBVRI photometry of the FK5 Extension Catalogue Stars  

NASA Astrophysics Data System (ADS)

UBVRI photometry in the Kron-Cousins system for 272 stars of the Extension Catalogue of the Fifth Fundamental Star Catalogue (FK5 stars) in the declination zone +7 deg to -90 deg is presented. Tables 1-2 are also available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html Based on observations made at the European Southern Observatory, La Silla, Chile.

Carrasco, G.; Ledoux, C.; Loyola, P.

1997-12-01

296

CCD based phase resolved stroboscopic photometry of pulsars  

E-print Network

A stroboscope designed to observe pulsars in the optical spectrum is presented. The absolute phase of the stroboscope is synchronized to better than 2.5 microseconds with the known radio ephemerides for a given pulsar. The absolute timing is provided by the GPS clock. With such a device phase resolved photometry of pulsars can be performed. We demonstrate the instrument's capabilities with the results of a set of observations of the Crab pulsar, the brightest of the known optical pulsars, with a visual magnitude of 16.5, and a rotational frequency of ~29Hz.

Kotar, J; Cadez, A; Kotar, Jurij; Vidrih, Simon; Cadez, Andrej

2003-01-01

297

CCD based phase resolved stroboscopic photometry of pulsars  

E-print Network

A stroboscope designed to observe pulsars in the optical spectrum is presented. The absolute phase of the stroboscope is synchronized to better than 2.5 microseconds with the known radio ephemerides for a given pulsar. The absolute timing is provided by the GPS clock. With such a device phase resolved photometry of pulsars can be performed. We demonstrate the instrument's capabilities with the results of a set of observations of the Crab pulsar, the brightest of the known optical pulsars, with a visual magnitude of 16.5, and a rotational frequency of ~29Hz.

Jurij Kotar; Simon Vidrih; Andrej Cadez

2003-03-17

298

CCD-photometry of comets at large heliocentric distances  

NASA Technical Reports Server (NTRS)

CCD imaging and time series photometry are used to determine the state of activity, nuclear properties and eventually the rotational motion of cometary nuclei. Cometary activity at large heliocentric distances and mantle evolution are not yet fully understood. Results of observations carried out at the 2.1 telescope on Kitt Peak April 10-12 and May 15-16, 1991 are discussed. Color values and color-color diagrams are presented for several comets and asteroids. Estimations of nuclear radii and shapes are given.

Mueller, Beatrice E. A.

1992-01-01

299

Broadband Photometry of the Potentially Hazardous Asteroid 2013 RH74  

NASA Astrophysics Data System (ADS)

The Near-Earth Asteroid (NEA) 2013 RH74 was discovered by the Catalina Sky Survey on September 15 2013 (MPEC 2013-S15) and has been designated as a Potentially Hazardous Asteroid (PHA) by the Minor Planet Center. We obtained six partial nights of broadband Bessel BVRI photometry at the JPL Table Mountain 0.6-m telescope (TMO), as summarized in Table 1. This object was detected by planetary radar soon after discovery (http://echo.jpl.nasa.gov/asteroids/index.html).

Hicks, M.; Ebelhar, S.

2013-11-01

300

CCD-Delta a and BVR photometry of NGC 7296  

E-print Network

The first CCD photometric investigation of the open cluster NGC 7296 up to now was performed within the narrow band Delta a photometric system, which enables us to detect peculiar objects. A deeper investigation of that cluster followed, using the standard BVR-Bessel filter set. The age and E(B-V) was determined independently to log t= 8.0 and 0.15 respectively by using Delta a and broadband photometry. In total five Be/Ae objects and two metal-weak stars showing significant negative Delta a-values as well as one classical chemically peculiar star could be identified within that intermediate age open cluster.

M. Netopil; E. Paunzen; H. M. Maitzen; A. Claret; K. Pavlovski; E. Tamajo

2005-07-25

301

CCD time-resolved photometry of faint cataclysmic variables. III  

NASA Technical Reports Server (NTRS)

CCD time-resolved photometry in V, B, and near-IR for 17 faint cataclysmic variables (CVs) is presented and analyzed. The data are obtained at Kitt Peak National Observatory, the Perkins reflector, Lowell Observatory, and the Observatorio del Roque de los Muchachos from April-June 1989. The degree of variability and periodicities for the CVs are examined. It is observed that the variability of most of the stars is consistent with CV class behavior. Orbital periods for five CVs are determined, and three potential eclipsing systems are detected.

Howell, Steve B.; Szkody, Paula; Kreidl, Tobias J.; Mason, Keith O.; Puchnarewicz, E. M.

1990-01-01

302

Optical photometry and spectroscopy of Nova Del 2013  

NASA Astrophysics Data System (ADS)

We report optical BV photometry and spectroscopy of Nova Del 2013, carried out between August 14.88 UT and August 15.08 UT. Using a 60 cm Cassegrain telescope at the Nicolaus Copernicus University Observatory (Torun, Poland) we estimated the V brightness of the Nova to be 6.31+/-0.02 mag and 6.18+/-0.03 mag on Aug. 14.94 UT and Aug. 15.02 UT respectively. HD 194113 (F2, V=8.00 mag) was used as a comparison star.

Tomov, T.; Ilkiewicz, K.; Swierczynski, E.; Belcheva, M.; Dimitrov, D.

2013-08-01

303

LEMON: an (almost) completely automated differential-photometry pipeline  

NASA Astrophysics Data System (ADS)

We present LEMON, the CCD differential-photometry pipeline, written in Python, developed at the Institute of Astrophysics of Andalusia (CSIC) and originally designed for its use at the 1.23 m CAHA telescope for automated variable stars detection and analysis. The aim of our tool is to make it possible to completely reduce thousands of images of time series in a matter of hours and with minimal user interaction, if not none at all, automatically detecting variable stars and presenting the results to the astronomer.

Terrón, V.; Fernández, M.

2011-11-01

304

EUVE photometry of SS Cygni: Dwarf nova outbursts and oscillations  

SciTech Connect

The authors present EUVE Deep Survey photometry and AAVSO optical measurements of the 1993 August and 1994 June/July outbursts of the dwarf nova SS Cygni. The EUV and optical light curves are used to illustrate the different response of the accretion disk to outbursts which begin at the inner edge and propagate outward, and those which begin at the outer edge and propagate inward. Furthermore, the authors describe the properties of the quasi-coherent 7--9 s sinusoidal oscillations in the EUV flux detected during the rise and plateau stages of these outbursts.

Mauche, C.W.

1995-05-15

305

uvby photometry in McCormick proper motion fields  

NASA Technical Reports Server (NTRS)

The Danish 50 cm telescope at the European Southern Observatory was used to obtain high-precision uvby photometry for 50 F2 to G2 stars, with V values in the 9.4-12.3 mag range, which were selected in the southern galactic polar regions of the McCormick proper motion fields and measured on six different nights. The brighter stars are found to systematically exhibit smaller m(1) indices, of about 0.02 mag, upon comparison with the earlier data of Blaauw et al (1976). Single measurements are given for 98 stars in eight McCormick fields at intermediate southern galactic latitudes.

Degewij, J.

1982-01-01

306

CCD Photometry of SW Ursae Majoris during the 1996 Superoutburst  

NASA Astrophysics Data System (ADS)

Differential CCD photometry of the 1996 April superoutburst of SW UMa was performed both at the Nicholas Copernicus Observatory and at the Ouda Station, Kyoto University. Although superhumps with a period of 0.05818 (+/- 0.00002) d and possible small-amplitude quasi periodic oscillations (QPOs) were detected, we failed to find the so-called super-QPOs. SW UMa has been proved to be the fourth SU UMa-type dwarf nova, following AL Com, V1028 Cyg, and HV Vir, in which an analysis of the superhump maxima timings revealed an increase in the superhump period.

Nogami, Daisaku; Baba, Hajime; Kato, Taichi; Novak, Rudolf

1998-04-01

307

BVR-band photometry of six novae in M31  

NASA Astrophysics Data System (ADS)

We report additional BVR-band photometry for the novae candidates - Nova M31 2013-11a (ATel # 5539, ATel # 5569), Nova M31 2013-11b = red LPV (ATel # 5569, ATel # 5640), Nova M31 2013-11d (ATel # 5605), Nova M31 2013-12a = Swift J004249.9+411457 (ATel # 5569, ATel # 5677), Nova M31 2013-12b = PNV J00425172+4118142 (ATel # 5671, ATel # 5723) and Nova M31 2014-01a = PNV J00431362+4114469.

Ovcharov, E.; Enikova, P.; Dimitrov, A.; Bozhilov, V.; Valcheva, A.; Nedialkov, P.

2014-01-01

308

Extreme Ultraviolet Explorer Photometry of RS Canum Venaticorum Systems: Four Flaring Megaseconds  

NASA Astrophysics Data System (ADS)

We present an analysis of 12.2 Ms of Extreme Ultraviolet Explorer (EUVE) photometry of 16 RS CVn systems (including four flaring megaseconds). Our study attempts a systematic categorization of stellar coronal emission in RS CVn binary systems. The temporal resolution of the EUVE satellite and the opportunity for long observations enables us to study separately the quiescent and flaring states of RS CVn systems. Thirty of 31 observations are statistically variable. We examine light curves, characterizing both phase-dependent variations and large- and small-scale flaring. There is evidence for small-scale stochastic variability on the one short-period (Porb<1 day) system in our sample (ER Vul), which we interpret as small-scale flaring. CF Tuc is the only system for which phase-dependent variations over multiple orbital periods are seen. We analyze 30 flares on nine systems, fitting rise and decay times. Several flares have durations >0.5Porb and thus cannot originate from compact emission regions close to the stellar surfaces. Many flares have unusual flare morphologies, with rise times comparable to or greater than the decay time, and emission plateaus. In addition, eight flares have decay phases that are fit better by a broken power law than a single power law. The decay times for the second power law are statistically different than the single decay times and are correlated with the flare rise times. This observed connection points to the potential importance of the change in decay rate as a means of examining the physical processes operating during the flare. The distribution of orbital phases of flare onsets on V711 Tau (HR 1099), the best-studied RS CVn in our sample, is consistent with a Poisson distribution that is random in time. In two systems that are partially eclipsing (CF Tuc and ER Vul), we find no evidence for an eclipse in the light curve, indicating that the emission region is large compared to the stellar radius. We parameterize the distribution of flare energies as a power law, finding a cut-off energy of ~1033 ergs and a slope of -0.6. Flare energy increases with flare duration as E~?t1.42, confirming the long-duration nature of high-energy flares on RS CVn systems. The integrated flare luminosity depends on the quiescent luminosity as Lflare~L1.05quiescent. Flare frequencies range from 0.1 day-1 to 1.5 day-1. For observations not affected by the dead spot on the Deep Survey detector, 40% of the observed time was spent in a flaring state, indicating that flaring is a ``normal'' state for the coronae of these systems. We note the presence of a quasi-periodicity in EUVE photometric data on the order of 1 day, which is not corrected for in the standard reduction and analysis software.

Osten, Rachel A.; Brown, Alexander

1999-04-01

309

Near-IR Spectroscopy and Visual Broadband Photometry of Unbound Asteroid Pairs  

NASA Astrophysics Data System (ADS)

Over 62 pairs of asteroids have been identified with extremely similar orbits (Rozek, Breiter, and Jopek 2011, MNRAS 412, 987). Backwards integration of their orbits show that each pair probably experienced a very low-velocity close encounter, in many cases less than 1 Myr ago (e.g. Vokrouhlický and Nesvorný 2008, AJ 136, 280). Pravec et al. (2010, Nature, 466, 1085) examined 35 pairs and found that the secondary/primary mass ratio is <0.2. Also, as this ratio approaches 0.2, the rotation period of the primary increases. This is consistent with formation of the pairs through rotational fission of a parent rubble-pile asteroid (Scheeres 2007, Icarus 189, 370). However, the pairs were linked through dynamical considerations alone, and mass ratios were determined using catalogued visual magnitudes and the assumption that the albedos and bulk densities of the components are identical. We are undertaking a campaign of characterising the asteroids in these pairs using visual and NIR spectroscopy as well as thermal IR photometry. We present 0.8-2.5 micron spectroscopic observations of using SpeX on NASA-IRTF, and BVRI photometry using the 0.6-m Table Mountain Observatory telescope. Our goals are to assess the similarity of the spectra of the components’ surfaces (e.g. Duddy et al. 2012, A&A, 539, A36) and also to look for evidence of color variation as a function of rotational phase. Since dynamical studies have placed constraints on the formation ages, if the asteroids are completely resurfaced during formation, we can start to explore the timescales involved in space weathering. We report recent progress in our investigations. This work was supported in part by the NASA Planetary Astronomy Program and done in part at the Jet Propulsion Laboratory under contract with NASA.

Wolters, Stephen D.; Weissman, P.; Duddy, S. R.; Christou, A.; Green, S. F.; Lowry, S. C.; Rozitis, B.

2012-10-01

310

Boundary-Layer Transition on Hollow Cylinders in Supersonic Free Flight as Affected by Mach Number and a Screwthread Type of Surface Roughness  

NASA Technical Reports Server (NTRS)

The effects of Mach number and surface-roughness variation on boundary-layer transition were studied using fin-stabilized hollow-tube models in free flight. The tests were conducted over the Mach number range from 2.8 to 7 at a nominally constant unit Reynolds number of 3 million per inch, and with heat transfer to the model surface. A screwthread type of distributed two-dimensional roughness was used. Nominal thread heights varied from 100 microinches to 2100 microinches. Transition Reynolds number was found to increase with increasing Mach number at a rate depending simultaneously on Mach number and roughness height. The laminar boundary layer was found to tolerate increasing amounts of roughness as Mach number increased. For a given Mach number an optimum roughness height was found which gave a maximum laminar run greater than was obtained with a smooth surface.

James, Carlton S.

1959-01-01

311

Surface composition of Pluto  

NASA Technical Reports Server (NTRS)

Broadband (J, H, K and L) and narrowband (1.5- to 3.7-micron) infrared photometry of Pluto has been conducted in order to check previous ambiguous observations of methane frost on the planet's surface. In detail, the match between a laboratory spectrum of methane frost and the observed spectrum of Pluto is not good. Nevertheless, the photometric observations suggest the presence of methane in some form.

Lebofsky, L. A.; Lebofsky, M. J.; Rieke, G. H.

1979-01-01

312

UBV Photometry of the young open cluster Berkely 87  

NASA Astrophysics Data System (ADS)

We obtained UBV imaging of a field in the young open cluster Berkeley 87. From these images, we measured the brightness of ~180 stars in the cluster. Our photometry was calibrated using published photometry (Turner & Forbes 1982 PASP 94, 789) of a subset of stars in our field. The cluster is in a region of the sky with strongly varying extinction. Therefore we made a (U-B)-(B-V) color-color diagram of the field and used this to de-redden the stars on a case by case basis. We de-reddened the stars using the unreddened supergiant and main sequence colors from Astrophysical Quantities (Cox 2000).The color-magnitude diagrams of the de-reddened stars are compared to the Padova isochrones(Marigo et al 2008 A&A 482 883). The isochrones are generated for a range of ages, with solar metalicity and no ? enhancement. The best fit for the isochrones was the main sequence de-reddened stars from which the age of the cluster is estimated to be 20 million years. This is older than previous age estimates (1-5 million years) from earlier studies of the cluster. This may indicate age variation in the cluster.We acknowledge the support of the Physics and Astronomy department, and the College of Science and Engineering, Minnesota State University, Mankato.

Akinyemi, Abolaji; Eskridge, Paul B.

2015-01-01

313

BVI CCD photometry of the globular cluster M4  

SciTech Connect

CCD BV1 main-sequence (MS) photometry of M4, the globular cluster closest to the sun, is presented. The photometry is matched to the BVI isochrones of VandenBerg and Bell (1985). The MS turnoffs are found to be at V = 16.90 + or - 0.05, B-V = 0.81 + or - 0.02, V-I = 0.96 + or - 0.02, and B - I = 1.77 + or - 0.02. The magnitude difference between the MS turnoff and the horizontal branch is Delta M(V) = 3.52 + or - 0.1 for all three color indices. Using Y = 0.2, (Fe/H) = - 1.27, and alpha = 1.65, with a distance modulus of (m-M)V = 12.7 and E(B-V) = 0.41, a consistent age for M4 is deduced in all three color indices of 17 + or - 1.5 Gyr. 34 references.

Alcaino, G.; Liller, W.; Alvarado, F.

1988-07-01

314

Differential Photometry of Asteroids 727 Nipponia and 741 Botolphia  

NASA Astrophysics Data System (ADS)

Differential photometry of the asteroids 727 Nipponia and 741 Botolphia yielded light curves and periods consistent with those available from observers of the Observatoire de Geneve. Data were collected with the SARA 0.9-m telescope at KPNO over the nights of April 27, 2003, May 14, 2004, and June 27-29, 2004, using an Apogee AP7p 511x512 CCD camera, and reduced with Mira 6.0 and IDL routines. This project will help find the rotation period of several primitive asteroids and follow up with spectral analyses to determine where on these asteroids water of hydration may be located. The Nipponia data cover a full rotation period (nominally 5.07h) and the phased light curve resembles those of Behrend et al. at the Ob. Geneve (http://obswww.unige.ch/ behrend/). The Botolphia data cover a quarter of the almost 24-h (provisional) period, and supplement light curves available from the Ob. Geneve groups. Both asteroids are small (about 30 km), mid-belt, of uncertain taxonomy (DT for Nipponia, X for Botolphia), and have slightly high albedo (0.14 to 0.24); whether they are "primitive" is uncertain. Continuing differential photometry at varying phase angles and spectral analyses are planned to examine the spectral heterogeneity of these objects and to search for water of hydration. This research was part of the summer REU program at the Southeastern Association for Research in Astronomy (SARA), made possible by National Science Foundation Grant AST-0097616.

Leake, M. A.; Rollins, C.; Wark, T. J.

2004-11-01

315

A new look at photometry of the Moon  

USGS Publications Warehouse

We use ROLO photometry (Kieffer, H.H., Stone, T.C. [2005]. Astron. J. 129, 2887-2901) to characterize the before and after full Moon radiance variation for a typical highlands site and a typical mare site. Focusing on the phase angle range 45??. ) to calculate the scattering matrix and solve the radiative transfer equation for I/. F. The mean single scattering albedo is ??=0.808, the asymmetry parameter is ???cos. ?????=0.77 and the phase function is very strongly peaked in both the forward and backward scattering directions. The fit to the observations for the highland site is excellent and multiply scattered photons contribute 80% of I/. F. We conclude that either model, roughness or multiple scattering, can match the observations, but that the strongly anisotropic phase functions of realistic particles require rigorous calculation of many orders of scattering or spurious photometric roughness estimates are guaranteed. Our multiple scattering calculation is the first to combine: (1) a regolith model matched to the measured particle size distribution and index of refraction of the lunar soil, (2) a rigorous calculation of the particle phase function and solution of the radiative transfer equation, and (3) application to lunar photometry with absolute radiance calibration. ?? 2010 Elsevier Inc.

Goguen, J.D.; Stone, T.C.; Kieffer, H.H.; Buratti, B.J.

2010-01-01

316

PHOTOMETRY OF VARIABLE STARS FROM DOME A, ANTARCTICA  

SciTech Connect

Dome A on the Antarctic plateau is likely one of the best observing sites on Earth thanks to the excellent atmospheric conditions present at the site during the long polar winter night. We present high-cadence time-series aperture photometry of 10,000 stars with i < 14.5 mag located in a 23 deg{sup 2} region centered on the south celestial pole. The photometry was obtained with one of the CSTAR telescopes during 128 days of the 2008 Antarctic winter. We used this photometric data set to derive site statistics for Dome A and to search for variable stars. Thanks to the nearly uninterrupted synoptic coverage, we found six times as many variables as previous surveys with similar magnitude limits. We detected 157 variable stars, of which 55% were unclassified, 27% were likely binaries, and 17% were likely pulsating stars. The latter category includes {delta} Scuti, {gamma} Doradus, and RR Lyrae variables. One variable may be a transiting exoplanet.

Wang Lingzhi [Department of Astronomy, Beijing Normal University, Beijing 100875 (China); Macri, Lucas M.; Krisciunas, Kevin; Wang Lifan [Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States); Ashley, Michael C. B.; Lawrence, Jon S.; Luong-Van, Daniel; Storey, John W. V. [School of Physics, University of New South Wales, NSW 2052 (Australia); Cui Xiangqun; Gong Xuefei; Yuan Xiangyan [Nanjing Institute of Astronomical Optics and Technology, Nanjing 210042 (China); Feng Longlong; Yang Ji; Zhu Zhenxi [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Liu Qiang; Zhou Xu [National Astronomical Observatory of China, Chinese Academy of Sciences, Beijing 100012 (China); Pennypacker, Carl R. [Center for Astrophysics, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Shang Zhaohui [Department of Physics, Tianjin Normal University, Tianjin 300074 (China); Yang Huigen [Polar Research Institute of China, Pudong, Shanghai 200136 (China); York, Donald G. [Department of Astronomy and Astrophysics and Enrico Fermi Institute, University of Chicago, Chicago, IL 60637 (United States)

2011-11-15

317

Macho Proper Motions From Optical/Infrared Photometry  

E-print Network

Optical/infrared photometry can double the number of proper motion measurements of Massive Compact Objects (MACHOs) relative to single band photometry. The proper motion of a MACHO can be measured by finding the ratio $q$ of the (known) radius of the source star to the Einstein radius of the MACHO, $q=\\theta_s/\\theta_e$. A classic method for doing this is to look for the effect on the light curve of the finite size of the source. A modification of this method proposed by Witt (1995) is to look for color changes in the light curve due to the fact that the limb darkening of the source is different in different bands. We demonstrate that the ``classical'' method is not feasible unless the MACHO actually transits the source: if the MACHO passes at say 1.5 source radii, there is still a sizable $\\sim 5\\%$ effect, but the light curve cannot be distinguished from point-source light curves with different parameters. However, color measurements in $V$ $(0.55\\,\\mu$m) and $H$ $(1.65\\,\\mu$m) reduce the errors by a factor $\\sim 120$ and permit proper motion measurements at impact parameters of up to 2 source radii. Color maps in $V-H$ are also useful in the detection of planetary systems. Giant stars have a ``red ring'' in such maps. A planet which transits this ring gives rise to a distinctive signature which can help in the measurement of the planetary system's proper motion.

Andrew Gould; Douglas L. Welch

1995-06-07

318

Stromvil Photometry of Clusters II. The Open Cluster M67  

NASA Astrophysics Data System (ADS)

Use of the Stromgren four-color photometric system with the addition of three filters (P, Z, S) of the Vilnius system allows classifying all the types of stars, even in the presence of significant reddening by interstellar dust (Strai\\v{z}ys et al, 1996). With this Stromvil system we have begun a long-term observational program on the Vatican Advanced Technology Telescope (VATT) on Mt. Graham, Arizona, (see Philip et al,1996). The Loral 2K by 2K CCD, prepared by M. Lesser of the University of Arizona CCD Lab, gives as high as 90% quantum efficiency in most of the filters and notably 65% at the u filter. To demonstrate the degree of success so far attained in this CCD Stromvil System, we present preliminary results on the open cluster M67. We will compare some of our photometry with the CCD results of B. A. Twarog (1987) and the photoelectric photometry of Nissen et al. (1987). REFERENCES Nissen, P.E., Twarog, B.A., and Crawford, D.L. 1987, A.J. 93,634 Philip, A.G. Davis, Boyle, R.P., Strai\\v{z}ys, V. 1996, Baltic Astronomy,5,445 Strai\\v{z}ys, V., Crawford, D.L., Philip, A.G.Davis 1996, Baltic Astronomy, 5,83 Twarog, B.A. 1987, A.J. 93,647

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

1998-12-01

319

Stromvil CCD Photometry in Globular Cluster M 3  

NASA Astrophysics Data System (ADS)

We observed the globular cluster M 3 in the 7-band Stromvil system plus Vilnius X-band at the 1.8-m Vatican Advanced Technology Telescope with a 2K CCD giving a 6-arcmin field. We observed the open cluster M 67 in the same run. Here from the residuals of many stars fit to quality CCD Vilnius photometry (Laugalys et al., 2004, Baltic Astronomy, 13, 1) we reshape and thus correct the initial flatfields. M 67 with a wide color base gives the color transformations of the run by calibrating from about 12 photoelectric standards in the Stromvil and similar Vilnius systems. In M 3 six photoelectric standards of moderate quality, all red stars of 13th magnitude in the Vilnius system calibrate the zero-point magnitude scale. Point-spread-function fitting to the stars in the crowded M 3 field resolves blends. With relatively short exposures of minutes a limiting magnitude V=15 is obtained with a signal/noise ratio about 100. So from this new photometry we subsequently can classify all types of stars and treat questions of reddening, distances, membership and metallicity at least at the horizontal branch of the cluster.

Boyle, Richard P.; Janusz, R.; Philip, A. G. D.; Straizys, V.; Vrba, F.

2007-12-01

320

Macular Pigment Optical Density Measured by Heterochromatic Modulation Photometry  

PubMed Central

Purpose To psychophysically determine macular pigment optical density (MPOD) employing the heterochromatic modulation photometry (HMP) paradigm by estimating 460 nm absorption at central and peripheral retinal locations. Methods For the HMP measurements, two lights (B: 460 nm and R: 660 nm) were presented in a test field and were modulated in counterphase at medium or high frequencies. The contrasts of the two lights were varied in tandem to determine flicker detection thresholds. Detection thresholds were measured for different R:B modulation ratios. The modulation ratio with minimal sensitivity (maximal threshold) is the point of equiluminance. Measurements were performed in 25 normal subjects (11 male, 14 female; age: 30±11 years, mean ± sd) using an eight channel LED stimulator with Maxwellian view optics. The results were compared with those from two published techniques – one based on heterochromatic flicker photometry (Macular Densitometer) and the other on fundus reflectometry (MPR). Results We were able to estimate MPOD with HMP using a modified theoretical model that was fitted to the HMP data. The resultant MPODHMP values correlated significantly with the MPODMPR values and with the MPODHFP values obtained at 0.25° and 0.5° retinal eccentricity. Conclusions HMP is a flicker-based method with measurements taken at a constant mean chromaticity and luminance. The data can be well fit by a model that allows all data points to contribute to the photometric equality estimate. Therefore, we think that HMP may be a useful method for MPOD measurements, in basic and clinical vision experiments. PMID:25354049

Huchzermeyer, Cord; Schlomberg, Juliane; Welge-Lüssen, Ulrich; Berendschot, Tos T. J. M.; Pokorny, Joel; Kremers, Jan

2014-01-01

321

Optimal addition of images for detection and photometry  

NASA Technical Reports Server (NTRS)

In this paper we describe weighting techniques used for the optimal coaddition of charge coupled devices (CCD) frames with differing characteristics. Optimal means maximum signal to noise (S/N) for stellar objects. We derive formulas for four applications: (1) object detection via matched filter, (2) object detection identical to DAOFIND, (3) aperture photometry, and (4) ALLSTAR profile-fitting photometry. We have included examples involving 21 frames for which either the sky brightness or image resolution varied by a factor of 3. The gains in S/N were modest for most of the examples, except for DAOFIND detection with varying image resolution which exhibited a substantial S/N increase. Even though the only consideration was maximizing S/N, the image resolution was seen to improve for most of the variable resolution examples. Also discussed are empirical fits for the weighting and the availability of the program, WEIGHT, used to generate the weighting for the individual frames. Finally, we include appendices describing the effects of clipping algorithms and a scheme for star/galaxy and cosmic-ray/star discrimination. scheme for star/galaxy and cosmic-ray/star discrimination.

Fischer, Philippe; Kochanski, Greg P.

1994-01-01

322

Testing theoretical models of subdwarf B stars using multicolor photometry  

NASA Astrophysics Data System (ADS)

Pulsating stars allow a direct investigation of their structure and evolutionary history from the evaluation of pulsation modes. However, the observed pulsation frequencies must first be identified with spherical harmonics (modes). For subdwarfs B (sdB) stars, such identifications using white light photometry currently have significant limitations. We intend to use multicolor photometry to identify pulsation modes and constrain structure models. We propose to observe the pulsating sdB star PG0154+182 (BI Ari) with our multicolor instrument GT Cam. Our observations will be compared with perturbative atmospheric models (BRUCE/KYLIE) to identify the pulsation modes. This is part of our NSF grant to obtain seismic tools to test structure and evolution models; constraining stellar parameters including total mass, envelope mass, internal composition discontinuities and internal rotation. During winter/spring 2012, we were allocated three runs on the 2.1 m to collect multicolor data on other promising pulsating subdwarf B stars as part of this work. Those runs were very successful, prompting our continued proposals. In addition, we will obtain 3-color data using MAIA on the Mercator Telescope (using guaranteed institutional time).

Reed, Mike; Baran, Andrzej; Ostensen, Roy; O'Toole, Simon

2012-08-01

323

Acidic deposition: State of science and technology. Report 10. Watershed and lake processes affecting surface-water acid-base chemistry. Final report  

Microsoft Academic Search

The acid-base chemistry of surface waters is governed by the amount and chemistry of deposition and by the biogeochemical reactions that generate acidity or acid neutralizing capacity (ANC) along the hydrologic pathways that water follows through watersheds to streams and lakes. The amount of precipitation and it chemical loading depend on the area's climate and physiography, on it proximity to

R. S. Turner; R. B. Cook; H. V. Miegroet; D. W. Johnson; J. W. Elwood

1990-01-01

324

VizieR Online Data Catalog: JHK photometry of CBJC 8 sources (Persi+, 2011)  

NASA Astrophysics Data System (ADS)

Coordinates (J2000) and JHK photometry are given for the 493 sources detected with PANIC on Baade Telescope in an area of 111"x111" centred on G85.40+0.00 as well as photometry in the four IRAC bands measured on archive frames of the same area. (2 data files).

Persi, P.; Tapia, M.; Gomez, M.

2010-11-01

325

HATnet VARIABILITY SURVEY IN THE HIGH STELLAR DENSITY ``KEPLER FIELD'' WITH MILLIMAGNITUDE IMAGE SUBTRACTION PHOTOMETRY  

E-print Network

SUBTRACTION PHOTOMETRY J. D. Hartman, G. Bakos,1, 2 K. Z. Stanek, and R. W. Noyes Harvard-Smithsonian Center subtraction photometry to reduce a crowded stellar field observed with one of the HATnet telescopes (HAT-5 have made use of the image subtraction techniques due to Alard & Lupton (1998; see also Alard 2000

Hillenbrand, Lynne

326

VizieR Online Data Catalog: Near-infrared photometry of {eta} Carinae (Mehner+, 2014)  

NASA Astrophysics Data System (ADS)

We present JHKL photometry of eta Car obtained at SAAO Sutherland from 2004-2013 with the Mk II photometer at the 0.75-m telescope and JHKs photometry with SIRIUS at the 1.4-m IRSF telescope from 2012-2013. (2 data files).

Mehner, A.; Ishibashi, K.; Whitelock, P.; Nagayama, T.; Feast, M.; van Wyk, F.; de Wit, W.-J.

2014-01-01

327

High-Speed CCD Photometry of White Dwarfs with a Small Telescope  

NASA Astrophysics Data System (ADS)

Small telescopes face a mission crisis and lack of funding in this age of bigger and bigger telescopes. High speed photometry of white dwarfs and other variables is a field in which these telescopes can be vital participants. We present high speed photometry taken at Mt. Cuba Observatory in Wilmington, Delaware, in collaboration with the Whole Earth Telescope.

Provencal, J. L.; Shipman, H. L.

2003-12-01

328

A Comparison of several commonly available software systems for aperture photometry with applications to photometry of blazars  

NASA Astrophysics Data System (ADS)

We have compared aperture photometry results for the commonly available software systems MaximDL, AIP4WIN, and IRAF. The comparison has utilized a sequence of images of the field surrounding the blazar BL Lac. Although a photometric sequence with standard magnitudes and colors is available in this field, we have concentrated on instrumental magnitudes. Our comparison consists of magnitude differences for a selection of stars in the field. We have considered single comparison and check stars as well as multiple comparison stars. We have also rigorously evaluated measurement errors. Our comparison has also considered a synthetic image of five noise-free stars. Our conclusions will consist of recommendations for procedures to derive magnitudes and error estimates for applications involving photometry of variable sources. All of our images and results will be available for downloading for instructional applications and for further comparisons. This work is supported by NASA's GLAST Education and Public Outreach Group. For more information about the supporting program and this paper visit: http://gtn.sonoma.edu/public/

Graves, T. G.; Spear, G. G.; McLin, K.; Plait, P. C.; Cominsky, L. R.; GLAST Education; Public Outreach Team

2005-12-01

329

Effect of sampling method on contaminant measurement in pore-water and surface water at two uranium operations: can method affect conclusions?  

Microsoft Academic Search

This paper describes a comparison of two methods of sediment pore-water sampling and two methods of surface water sampling\\u000a that were used in a broader investigation of cause(s) of adverse effects on benthic invertebrate communities at two Saskatchewan\\u000a uranium operations (Key Lake and Rabbit Lake). Variables measured and compared included pH, ammonia, DOC, and trace metals.\\u000a The two types of

Erin L. Robertson; Karsten Liber

2009-01-01

330

Porous medium coffee ring effect and other factors affecting the first crystallisation time of sodium chloride at the surface of a drying porous medium  

NASA Astrophysics Data System (ADS)

We study the distribution of ions in a drying porous medium up to the formation of first crystals at the surface. The study is based on comparisons between numerical simulations and experiments with packings of glass beads. The experimental configuration, which is representative of many previous drying experiments, is characterized by the formation of an efflorescence fairy ring at the surface of the porous medium. The preferential formation of crystals at the periphery is explained by the combined effect of higher evaporation fluxes at the surface periphery, as in the classical coffee ring problem, and variations in the porosity near the wall bordering the packing. It is shown that both effects have a great impact on the time marking the occurrence of first crystals, which is referred to as the first crystallization time. The experiments indicate that the first crystallization time increases with a decreasing bead size for a given initial ion concentration. This is explained by the variation with bead size of the characteristic size of the near wall region where a preferential desaturation of the sample occurs as a result of the porosity increase near the wall. The study also reveals a significant salt supersaturation effect. This represents a noticeable fact in relation with salt weathering issues.

Hidri, F.; Sghaier, N.; Eloukabi, H.; Prat, M.; Nasrallah, S. Ben

2013-12-01

331

Spinocerebellar ataxia-13 Kv3.3 potassium channels: arginine-to-histidine mutations affect both functional and protein expression on the cell surface.  

PubMed

The voltage-gated potassium channel Kv3.3 is the causative gene of SCA13 (spinocerebellar ataxia type 13), an autosomal dominant neurological disorder. The four dominant mutations identified to date cause Kv3.3 channels to be non-functional or have altered gating properties in Xenopus oocytes. In the present paper, we report that SCA13 mutations affect functional as well as protein expression of Kv3.3 channels in a mammalian cell line. The reduced protein level of SCA13 mutants is caused by a shorter protein half-life, and blocking the ubiquitin-proteasome pathway increases the total protein of SCA13 mutants more than wild-type. SCA13 mutated amino acids are highly conserved, and the side chains of these residues play a critical role in the stable expression of Kv3.3 proteins. In addition, we show that mutant Kv3.3 protein levels could be partially rescued by treatment with the chemical chaperone TMAO (trimethylamine N-oxide) and to a lesser extent with co-expression of Kv3.1b. Thus our results suggest that amino acid side chains of SCA13 positions affect the protein half-life and/or function of Kv3.3, and the adverse effect on protein expression cannot be fully rescued. PMID:23734863

Zhao, Jian; Zhu, Jing; Thornhill, William B

2013-09-01

332

Effect of sampling method on contaminant measurement in pore-water and surface water at two uranium operations: can method affect conclusions?  

PubMed

This paper describes a comparison of two methods of sediment pore-water sampling and two methods of surface water sampling that were used in a broader investigation of cause(s) of adverse effects on benthic invertebrate communities at two Saskatchewan uranium operations (Key Lake and Rabbit Lake). Variables measured and compared included pH, ammonia, DOC, and trace metals. The two types of sediment pore-water samples that were compared are centrifuged and 0.45-microm filtered sediment core samples vs. 0.2-microm dialysis (peeper) samples. The two types of surface water samples that were compared are 53-microm filtered Van Dorn horizontal beta samples vs. 0.2-microm dialysis (peeper) samples. Results showed that 62% of the sediment core pore water values were higher than the corresponding peeper pore-water measurements, and that 63% of the Van Dorn surface water measurements were lower than corresponding peeper surface water measurements. Furthermore, only 24% and 14% of surface water and pore-water measurements, respectively, fell within +/-10% range of one another; 73% and 50%, respectively, fell within +/-50%. Although somewhat confounded by differences in filtering method, the observed differences are believed to primarily be related to small, vertical differences in the environment sampled. Despite observed differences in concentrations of toxicologically relevant variables generated by the different sampling methods, the weight of evidence (WOE) conclusions drawn from each set of exposure data on the possible cause(s) of in situ toxicity to Hyalella azteca from a related study were the same at each uranium operation. However, this concurrence was largely due to other dominant lines of evidence. The WOE conclusions at Key Lake were dominated by the toxicity response of H. azteca in relation to exposure chemistry, where as the WOE conclusions at Rabbit Lake were informed by exposure chemistry, the toxicological response of H. azteca, and whole-body contaminant concentrations in the test organisms. Had these multiple lines of evidence not been available, differences in exposure chemistry generated by the different sampling methods could have substantially influenced the identification of potential causes of in situ toxicity. PMID:18726245

Robertson, Erin L; Liber, Karsten

2009-08-01

333

Time-series Photometry of the Pre-Main Sequence Binary V4046 Sgr: Testing the Accretion Stream Theory  

NASA Astrophysics Data System (ADS)

Most stars are born in binaries, and the evolution of protostellar disks in pre-main sequence (PMS) binary stars is a current frontier of star formation research. PMS binary stars can have up to three accretion disks: two circumstellar disks and a circumbinary disk separated by a dynamically cleared gap. Theory suggests that mass may periodically flow in an accretion stream from a circumbinary disk across the gap onto circumstellar disks or stellar surfaces. Thus, accretion in PMS binaries is controlled by not only radiation, disk viscosity, and magnetic fields, but also by orbital dynamics.As part of a larger, ongoing effort to characterize mass accretion in young binary systems, we test the predictions of the binary accretion stream theory through continuous, multi-orbit, multi-color optical and near-infrared (NIR) time-series photometry. Observations such as these are capable of detecting and characterizing these modulated accretion streams, if they are generally present. Broad-band blue and ultraviolet photometry trace the accretion luminosity and photospheric temperature while NIR photometry provide a measurement of warm circumstellar material, all as a function of orbital phase. The predicted phase and magnitude of enhanced accretion are highly dependent on the binary orbital parameters and as such, our campaign focuses on 10 PMS binaries of varying periods and eccentricities. Here we present multi-color optical (U, B,V, R), narrowband (H?), and multi-color NIR (J, H) lightcurves of the PMS binary V4046 Sgr (P=2.42 days) obtained with the SMARTS 1.3m telescope and LCOGT 1m telescope network. These results act to showcase the quality and breadth of data we have, or are currently obtaining, for each of the PMS binaries in our sample. With the full characterization of our sample, these observations will guide an extension of the accretion paradigm from single young stars to multiple systems.

Tofflemire, Benjamin M.; Mathieu, Robert D.; Ardila, David R.; Ciardi, David R.

2015-01-01

334

Results of the Lick Observatory Supernova Search Follow-up Photometry Program: BVRI Light Curves of 165 Type Ia Supernovae  

Microsoft Academic Search

We present BVRI light curves of 165 Type Ia supernovae (SNe Ia) from the Lick Observatory Supernova Search follow-up photometry program from 1998 through 2008. Our light curves are typically well sampled (cadence of 3-4 days) with an average of 21 photometry epochs. We describe our monitoring campaign and the photometry reduction pipeline that we have developed. Comparing our data

Mohan Ganeshalingam; Weidong Li; Alexei V. Filippenko; Carmen Anderson; Griffin Foster; Elinor L. Gates; Christopher V. Griffith; Bryant J. Grigsby; Niels Joubert; Joel Leja; Thomas B. Lowe; Brent Macomber; Tyler Pritchard; Patrick Thrasher; Dustin Winslow

2010-01-01

335

Submitted to Ap. J. Suppl. Catalog of Four-Color Photometry of Stars, Galaxies, and QSOs using SDSS  

E-print Network

Submitted to Ap. J. Suppl. Catalog of Four-Color Photometry of Stars, Galaxies, and QSOs using SDSS. The stars are compared with synthetic photometry from Kurucz models the agreement is consistent: photometry, quasars: general 1. Introduction The Sloan Digital Sky Survey (SDSS) is projected to produce

Varela, Carlos

336

VAPHOT -A Package for Precision Differential Aperture Photometry HANS J. DEEG1,2, LAURANCE R. DOYLE3  

E-print Network

VAPHOT - A Package for Precision Differential Aperture Photometry HANS J. DEEG1,2, LAURANCE R radius, diameter and 'size' is clarified Abstract The aperture photometry package `vaphot' was developed to perform reliable and precise time-series photometry of uncrowded fields. This package works within

Deeg, Hans-Jörg

337

PUSHING THE LIMITS OF GROUND-BASED PHOTOMETRIC PRECISION: SUBMILLIMAGNITUDE TIME-SERIES PHOTOMETRY OF THE OPEN CLUSTER NGC 6791  

E-print Network

PUSHING THE LIMITS OF GROUND-BASED PHOTOMETRIC PRECISION: SUBMILLIMAGNITUDE TIME-SERIES PHOTOMETRY of this study was to demonstrate the ability to obtain very high precision photometry for a large number to obtain high-precision (millimagnitude, or less than 1%) time-series, optical and infrared photometry

Gaudi, B. Scott

338

Resolved photometry of the binary components of RW Aur  

E-print Network

Resolved UBVRI photometry of RW Aur binary was performed on November 13/14, 2014 during the deep dimming of RW Aur with a newly installed 2.5 meter telescope of the Caucasus observatory of Lomonosov Moscow State University at the mount Shatzhatmaz. At that moment RW Aur A was $\\simeq 3^m$ fainter than in November 1994 in all spectral bands. We explain the current RW Aur A dimming as a result of eclipse of the star by dust particles with size $>1 \\mu m.$ We found that RW Aur B is also a variable star: it was brighter than 20 years ago at $0.7^m$ in each of UBVRI band (gray brightening).

Antipin, S; Cherepashchuk, A; Cherjasov, D; Dodin, A; Gorbunov, I; Lamzin, S; Kornilov, M; Kornilov, V; Potanin, S; Safonov, B; Senik, V; Shatsky, N; Voziakova, O

2014-01-01

339

UBVI CCD Photometry of Open Cluster NGC 2324  

NASA Astrophysics Data System (ADS)

UBVI CCD photometry of open cluster NGC 2324 is presented. C-M diagrams of this cluster show well-defined main sequence with a red giant clump centered at B-V=1.05, V=13.45. We derived the major cluster characteristics; E(B-V)=0.17+-0.12 from color-color diagram and mean color of red giant clump stars, (m-M)_0=13.1+-0.1 from zero age main sequence fitting, and [Fe/H] ~ -0.32 from comparison the theoretical model developed by Bertelli et al. (1994) to the observed C-M diagrams. We estimate the age of NGC 2324 to be logt ~ 8.8 by applying isochrone fitting and morphological age index method.

Kyeong, Jae-Mann; Byun, Yong-Ik; Sung, Eon-Chang

2001-12-01

340

UBVI CCD Photometry of the Old Open Cluster NGC 1193  

NASA Astrophysics Data System (ADS)

We present UBVI photometry of the old open cluster NGC 1193. Color-magnitude diagrams (CMDs) of this cluster show a well defined main sequence and a sparse red giant branch. For the inner region of r<50 arcsec, three blue straggler candidates are newly found in addition to the objects Kaluzny (1988) already found. The color-color diagrams show that the reddening value toward NGC 1193 is E(B-V) =0.19 ± 0.04. From the ultraviolet excess measurement, we derived the metallicity to be [Fe/H]=-0.45 ± 0.12. A distance modulus of (m-M)_0 =13.3 ± 0.15 is obtained from zero age main sequence fitting with the empirically calibrated Hyades isochrone of Pinsonneault et al. (2004). CMD comparison with the Padova isochrones by Bertelli et al. (1994) gives an age of log t =9.7 ± 0.1.

Kyeong, Jaemann; Kim, Sang Chul; Hiriart, David; Sung, Eon-Chang

2008-12-01

341

USING PHOTOMETRY TO PROBE THE CIRCUMSTELLAR ENVIRONMENT OF {delta} SCORPII  

SciTech Connect

We acquired Johnson BV photometry of the binary Be disk system {delta} Scorpii during its 2009, 2010, 2011, and 2012 observing seasons and used it to probe the innermost regions of the disk. We found that several disk building events have occurred during this time, resulting in an overall brightening in the V band and reddening of the system. In addition to these long-term trends, we found cyclical variability in each observing season on timescales between 60 and 100 days. We were able to reproduce the changes in the magnitude and color of {delta} Sco using our theoretical models and found that variable mass-loss rates in the range 2.5-7.0 Multiplication-Sign 10{sup -9} M{sub Sun} yr{sup -1} over {approx}35 days can reproduce the observed increase in brightness.

Jones, C. E.; Wiegert, P. A.; Cyr, R. P.; Halonen, R. J. [Department of Physics and Astronomy, Western University, London, ON N6A 3K7 (Canada); Tycner, C. [Department of Physics, Central Michigan University, Mt. Pleasant, MI 48859 (United States); Henry, G. W.; Muterspaugh, M. W. [Center of Excellence in Information Systems, Tennessee State University, 3500 John A. Merritt Blvd., Box No 9501, Nashville, TN 37209 (United States)

2013-05-15

342

Infrared Photometry of Asteroids Observed with the Spitzer Space Telescope  

NASA Astrophysics Data System (ADS)

We present photometric measurements of asteroids observed with the Spitzer Space Telescope. Photometry at 3.6, 4.5, 5.8, and 8.0 microns as well as at 24 microns using the IRAC and MIPS instruments is provided. We discuss time variability of flux for all known and newly identified asteroids in the Spitzer First Look Survey Ecliptic Plane Component. We also consider flux measurements and their implications on size estimation for known asteroids in the publicly available IRAC calibration data. The study presented here also demonstrates the usability of the JPL HORIZONS tool ISPY for identification of known asteroids in Spitzer fields. This work is based on observations made with the Spitzer Space Telescope, which is is operated by the Jet Propulsion Laboratory, California Institute of Technology under NASA contract 1407. Support for this work was provided by NASA through an award issued by JPL/Caltech.

Bhattacharya, B.; Meadows, V. S.; Grillmair, C.; Ryan, E.; Burgdorf, M.; Rebull, L.; Tyler, S.; Noriega-Crespo, A.; Morris, P.; Tedesco, E.; Giorgini, J.

2004-11-01

343

An interactive modular design for computerized photometry in spectrochemical analysis  

NASA Technical Reports Server (NTRS)

A general functional description of totally automatic photometry of emission spectra is not available for an operating environment in which the sample compositions and analysis procedures are low-volume and non-routine. The advantages of using an interactive approach to computer control in such an operating environment are demonstrated. This approach includes modular subroutines selected at multiple-option, menu-style decision points. This style of programming is used to trace elemental determinations, including the automated reading of spectrographic plates produced by a 3.4 m Ebert mount spectrograph using a dc-arc in an argon atmosphere. The simplified control logic and modular subroutine approach facilitates innovative research and program development, yet is easily adapted to routine tasks. Operator confidence and control are increased by the built-in options including degree of automation, amount of intermediate data printed out, amount of user prompting, and multidirectional decision points.

Bair, V. L.

1980-01-01

344

BVRI Photometry of SN 2013ej in M74  

NASA Astrophysics Data System (ADS)

I present BVRI photometry of the type IIP supernova 2013ej in M74 from 1 to 179 days after its discovery. These photometric measurements and spectroscopic data from the literature are combined via the expanding photosphere method to estimate the distance to the event, which is consistent with that derived by other methods. After correcting for extinction and adopting a distance modulus of (m – M) = 29.80 mag. to M74, I derive absolute magnitudes MB = –17.36, MV = –17.47, MR = –17.64 and MI = –17.71. The differences between visual measurements and CCD V-band measurements of SN 2013ej are similar to those determined for type Ia supernovae and ordinary stars.

Richmond, M. W.

2014-12-01

345

Prelude to, and Nature of the Space Photometry Revolution  

E-print Network

It is now less than a decade since CoRoT initiated the space photometry revolution with breakthrough discoveries, and five years since Kepler started a series of similar advances. I'll set the context for this revolution noting the status of asteroseismology and exoplanet discovery as it was 15-25 years ago in order to give perspective on why it is not mere hyperbole to claim CoRoT and Kepler fostered a revolution in our sciences. Primary events setting up the revolution will be recounted. I'll continue with noting the major discoveries in hand, and how asteroseismology and exoplanet studies, and indeed our approach to doing science, have been forever changed thanks to these spectacular missions.

Gilliland, Ronald L

2014-01-01

346

Resolved photometry of the binary components of RW Aur  

NASA Astrophysics Data System (ADS)

Resolved UBVRI photometry of RW Aur binary was performed on November 13/14, 2014 during the deep dimming of RW Aur with a newly installed 2.5 meter telescope of the Caucasus observatory of Lomonosov Moscow State University at the mount Shatzhatmaz. At that moment RW Aur A was $\\simeq 3^m$ fainter than in November 1994 in all spectral bands. We explain the current RW Aur A dimming as a result of eclipse of the star by dust particles with size $>1 \\mu m.$ We found that RW Aur B is also a variable star: it was brighter than 20 years ago at $0.7^m$ in each of UBVRI band (gray brightening).

Antipin, S.; Belinski, A.; Cherepashchuk, A.; Cherjasov, D.; Dodin, A.; Gorbunov, I.; Lamzin, S.; Kornilov, M.; Kornilov, V.; Potanin, S.; Safonov, B.; Senik, V.; Shatsky, N.; Voziakova, O.

2015-01-01

347

CCD photometry of 2060 Chiron in 1985 and 1991  

NASA Technical Reports Server (NTRS)

CCD photometry of 2060 Chiron from two apparitions, in January 1985 and January 1991, is reported. No evidence is found for a change in the amplitude of Chiron's lightcurve with ecliptic longitude, as would be expected of an object having a high-obliquity rotational axis. An improved value for Chiron's synodic period is reported: 5.917813 +/- 0.000007 hr. No outbursts larger than one-half of one percent were found during the 1991 observations. Secular (yearly) change is due to the gradual dissipation and resupply of material (mainly dust) throughout the coma, while the impulsive (daily) brightenings are probably due to the sudden release of pockets of entrapped volatiles, such as CO2, CN, or possibly H2O.

Marcialis, Robert L.; Buratti, Bonnie J.

1993-01-01

348

Geneva photometry in the young open cluster NGC 6231.  

NASA Astrophysics Data System (ADS)

We present photoelectric (127 stars) and CCD (168 stars) Geneva photometry for the very young open cluster NGC 6231. We have searched for new cluster members out to a distance of ~13['arc], extending the Seggewiss area (~8['arc]), and we found at least 64 new probable members in this extended field. Differential reddening is clearly measured across the cluster area. We determine the cluster distance (1800 pc) and age (3.8+/-0.6x10^6^yr). The probable presence of PMS stars and the consequence of this population on the cluster formation history is analysed. We also found that the O8.5III star S161 is a long term variable and we present its light curve extending over more than 20 years. Finally we discuss the existence of Ap stars in the cluster.

Raboud, D.; Cramer, N.; Bernasconi, P. A.

1997-09-01

349

Factors affecting the rent to surface-mined coal tracts in the Powder River Basin and Green River/Hams Fork Region  

SciTech Connect

This study develops a method to estimate annual rent to a coal tract which requires knowledge only of tract geological characteristics, mining technology characteristics derived from production function estimates, and prices. Cobb-Douglas and Constant Elasticity of Substitution production functions were estimated for twenty mines in the Powder River Basin and Green River/Hams Fork Region, using data on capital, labor, and energy inputs and data describing tract geological characteristics. The analysis found constant returns to scale and no effects of depletion on mining costs. The Cobb-Douglas specification appeared satisfactory. Surface coal mining in these two regions appears much less capital-intensive than nationwide estimates for surface coal mining previously offered. Of the geological characteristics considered in the analysis, only remaining reserves appear appropriately viewed as an input to mining. The stripping ratio (ratio of overburden to seam thickness) has a negative effect on tract rent. Almost exactly 12.5% of the value of output is attributable to the tract itself; so, keeping in mind the limitations of the data base and the statistical nature of the estimate, we suggest that the current federal royalty rate of 12.5% probably extracts a share of revenue very close to the government's ''proper'' share as owner of the tract. 20 refs.

Jones, D.W.; Hillsman, E.L.; Lee, R.; Foust, C.B.

1985-12-01

350

Geohydrology of the aquifers that may be affected by the surface mining of coal in the Fruitland Formation in the San Juan Basin, northwestern New Mexico  

USGS Publications Warehouse

A monitoring network of 50 wells was installed from 1975 to 1979 in the surface-mineable coal area. The purpose of the network was to collect hydrologic data and to establish a data base. The hydrologic data consist of water level measurements, water chemistry, and selected aquifer characteristics. The four aquifers considered in this study are: (1) The Pictured Cliffs Sandstone; (2) coal seams and interbedded lithologic units of the Fruitland Formation; (3) overburden of the Kirtland Shale and Fruitland Formation; and (4) the alluvium along the Chaco River and its eastern and northeastern tributaries. Five sites were selected for study. Four of these sites, Western Coal Company 's lease near Fruitland, Bisti West, Kimbeto, and Ojo Encino, have surface-mineable coal. The Chaco River alluvium was selected because it is downstream from anticipated mining activity. The specific conductances of the representative water samples from selected wells in the 4 aquifers in the 5 study areas ranged from 800 to 23,000 microsiemens/cm at 25 C. The dominant cation in all samples was sodium. The water is brackish in the Pictured Cliffs Sandstone and in the coal seams and interbedded lithologic units of the Fruitland Formation. It is fresh to saline in the overburden of the Fruitland Shale and Fruitland Formation, and fresh to brackish in the Chaco River alluvium. (Author 's abstract)

Myers, R.G.; Villanueva, E.D.

1986-01-01

351

Some molecular/crystalline factors that affect the sensitivities of energetic materials: molecular surface electrostatic potentials, lattice free space and maximum heat of detonation per unit volume.  

PubMed

We discuss three molecular/crystalline properties that we believe to be among the factors that influence the impact/shock sensitivities of energetic materials (i.e., their vulnerabilities to unintended detonation due to impact or shock). These properties are (a) the anomalously strong positive electrostatic potentials in the central regions of their molecular surfaces, (b) the free space per molecule in their crystal lattices, and (c) their maximum heats of detonation per unit volume. Overall, sensitivity tends to become greater as these properties increase; however these are general trends, not correlations. Nitramines are exceptions in that their sensitivities show little or no variation with free space in the lattice and heat of detonation per unit volume. We outline some of the events involved in detonation initiation and show how the three properties are related to different ones of these events. PMID:25631919

Politzer, Peter; Murray, Jane S

2015-02-01

352

Factors affecting the fate and transport of glyphosate and AMPA into surface waters of agricultural watersheds in the United States and Europe  

NASA Astrophysics Data System (ADS)

Glyphosate [N-(phosphonomethyl)glycine] is a herbicide used extensively in almost all agricultural and urban areas of the United States and Europe. Although, glyphosate is used widely throughout the world in the production of many crops, it is predominately used in the United States on soybeans, corn, potatoes, and cotton that have been genetically modified to be tolerant to glyphosate. From 1992 to 2007, the agricultural use of glyphosate has increased from less than 10,000 Mg to more than 80,000 Mg, respectively. The greatest areal use is in the midwestern United States where glyphosate is applied on transgenic corn and soybeans. Because of the difficulty and expense in analyzing for glyphosate and AMPA (aminomethylphosphonic acid, a primary glyphosate degradate) in water, there have been only small scale studies on the fate and transport of glyphosate. The characterization of the transport of glyphosate and AMPA on a watershed scale is lacking. Glyphosate and AMPA were frequently detected in the surface waters of 4 agricultural watersheds in studies conducted by the U.S. Geological Survey in the United States and at the Laboratory of Hydrology and Geochemistry of Strasbourg. Two of these basins were located in the midwestern United States where the major crops are corn and soybean, the third is located the lower Mississippi River Basin where the major crops are soybean, corn, rice, and cotton, and the fourth was located near Strasbourg, France where the use of glyphosate was on a vineyard. The load as a percent of use ranged from 0.009 to 0.86 percent and could be related to 3 factors: source strength, hydrology, and flowpath. Glyphosate use in a watershed results in some occurrence in surface water at the part per billion level; however, those watersheds most at risk for the offsite transport of glyphosate are those with high application rates, rainfall that results in overland runoff, and a flowpath that does not include transport through the soil.

Coupe, R.; Kalkhoff, S.; Capel, P.; Gregoire, C.

2012-04-01

353

EXTENDED PHOTOMETRY FOR THE DEEP2 GALAXY REDSHIFT SURVEY: A TESTBED FOR PHOTOMETRIC REDSHIFT EXPERIMENTS  

SciTech Connect

This paper describes a new catalog that supplements the existing DEEP2 Galaxy Redshift Survey photometric and spectroscopic catalogs with ugriz photometry from two other surveys: the Canada-France-Hawaii Legacy Survey (CFHTLS) and the Sloan Digital Sky Survey (SDSS). Each catalog is cross-matched by position on the sky in order to assign ugriz photometry to objects in the DEEP2 catalogs. We have recalibrated the CFHTLS photometry where it overlaps DEEP2 in order to provide a more uniform data set. We have also used this improved photometry to predict DEEP2 BRI photometry in regions where only poorer measurements were available previously. In addition, we have included improved astrometry tied to SDSS rather than USNO-A2.0 for all DEEP2 objects. In total this catalog contains {approx}27, 000 objects with full ugriz photometry as well as robust spectroscopic redshift measurements, 64% of which have r > 23. By combining the secure and accurate redshifts of the DEEP2 Galaxy Redshift Survey with ugriz photometry, we have created a catalog that can be used as an excellent testbed for future photo-z studies, including tests of algorithms for surveys such as LSST and DES.

Matthews, Daniel J.; Newman, Jeffrey A. [Department of Physics and Astronomy, University of Pittsburgh, 3941 O'Hara Street, Pittsburgh, PA 15260 (United States); Coil, Alison L. [Department of Physics, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093 (United States); Cooper, Michael C. [Center for Galaxy Evolution, Department of Physics and Astronomy, University of California, Irvine, 4129 Frederick Reines Hall, Irvine, CA 92697 (United States); Gwyn, Stephen D. J., E-mail: djm70@pitt.edu, E-mail: janewman@pitt.edu, E-mail: acoil@ucsd.edu, E-mail: m.cooper@uci.edu, E-mail: Stephen.Gwyn@nrc-cnrc.gc.ca [Canadian Astronomical Data Centre, Herzberg Institute of Astrophysics, 5071 West Saanich Road, Victoria, British Columbia V9E 2E7 (Canada)

2013-02-15

354

Are ciliated protozoa communities affected by macrophyte species, date of sampling and location in horizontal sub-surface flow constructed wetlands?  

PubMed

The effects of design and operational factors on the dynamics of ciliated protozoa in constructed wetlands (CWs) treating wastewater remain poorly known, although bacterivory by ciliates could have important implications for nutrient cycling in these systems. We conducted a greenhouse experiment with eight wetland mesocosms (1 m(2)) fed with synthetic wastewater to assess how macrophyte species (Phragmites australis, Phalaris arundinacea, and Typha angustifolia), location within CW (longitudinal, depth), and temporal fluctuations affect ciliate abundance and diversity. Urosoma similis was the most abundant taxon, but Hypotrichidae, Scuticociliates, Drepomonas revoluta, and Acineria uncinata were also abundant. Longitudinal location had the highest impact on ciliate dynamics, with more abundant and diverse communities in the initial section of wetlands. P. australis/T. angustifolia and P. arundinacea had the most and least favorable conditions for ciliates, respectively, but differences among macrophytes were mostly not significant. Ciliate abundance appeared to decline from August to November, most likely because of lower temperature and plant inputs of organic matter and oxygen. Depth had no apparent impact on ciliate dynamics, suggesting that sampling at multiple depths in CW is not necessary to adequately monitor ciliate communities. Overall, our results suggest that macrophytes, location, and date of sampling influenced ciliated dynamics but stress the need for direct manipulative experiments of ciliate abundance, diversity, and composition conducted on a full annual cycle to better understand the impact of ciliates on nutrient cycling in CWs. This is especially true to determine if the associations found in our principal component analysis are robust. PMID:22483709

Puigagut, Jaume; Maltais-Landry, Gabriel; Gagnon, Vincent; Brisson, Jacques

2012-06-01

355

THE ARAUCARIA PROJECT. A DISTANCE DETERMINATION TO THE LOCAL GROUP SPIRAL M33 FROM NEAR-INFRARED PHOTOMETRY OF CEPHEID VARIABLES  

SciTech Connect

Motivated by an amazing range of reported distances to the nearby Local Group spiral galaxy M33, we have obtained deep near-infrared photometry for 26 long-period Cepheids in this galaxy with the ESO Very Large Telescope. From the data, we constructed period-luminosity relations in the J and K bands which together with previous optical VI photometry for the Cepheids by Macri et al. were used to determine the true distance modulus of M33, and the mean reddening affecting the Cepheid sample with the multiwavelength fit method developed in the Araucaria Project. We find a true distance modulus of 24.62 for M33, with a total uncertainty of {+-}0.07 mag which is dominated by the uncertainty on the photometric zero points in our photometry. The reddening is determined as E(B - V) = 0.19 {+-} 0.02, in agreement with the value used by the Hubble Space Telescope Key Project of Freedman et al. but in some discrepancy with other recent determinations based on blue supergiant spectroscopy and an O-type eclipsing binary which yielded lower reddening values. Our derived M33 distance modulus is extremely insensitive to the adopted reddening law. We show that the possible effects of metallicity and crowding on our present distance determination are both at the 1%-2% level and therefore minor contributors to the total uncertainty of our distance result for M33.

Gieren, Wolfgang; Pietrzynski, Grzegorz; Graczyk, Dariusz, E-mail: wgieren@astro-udec.cl, E-mail: pietrzyn@hubble.cfm.udec.cl [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warsaw (Poland); and others

2013-08-10

356

The Consistency of Stromgren-Beta Photometry for Northern Galactic Clusters. II. Praesepe and NGC 752  

NASA Astrophysics Data System (ADS)

We have measured stars in Praesepe and NGC 752 in an internally-consistent Stromgren-Beta system. This system is based in large part on published Hyades and Coma measurements. On comparing our Praesepe results to those of Crawford and Barnes (1969, AJ, 74, 818), we find that the published color indices require corrections of 10-18 mmag to put them on the Hyades-Coma system. This deduction applies for b-y, m_1 and Beta (but not c_1). For the NGC 752 data of Crawford and Barnes (1970, AJ, 75, 946), we obtain a nonzero correction only for Beta. This correction is about 9 mmag. Also for NGC 752, we find that the data of Twarog (1983, ApJ, 267, 207) require corrections ranging from 4-17 mmag, with all Stromgren indices being affected and the largest correction being for m_1. These corrections resolve the long-standing problem posed by the differences between the Twarog and Crawford-Barnes data. For three published sources of V magnitudes, we obtain offsets ranging from -14 to +27 mmag relative to our zero point, and we suggest that such offsets are fairly common in published photometry for galactic clusters. For Praesepe, we use new and corrected data to test for a c_1 anomaly and is indistinguishable from Coma in that regard. (SECTION: Stellar Clusters and Associations)

Joner, Michael D.; Taylor, Benjamin J.

1995-04-01

357

Resolved photometry of extragalactic young massive star clusters  

NASA Astrophysics Data System (ADS)

Aims: We present colour-magnitude diagrams (CMDs) of young massive star clusters in several galaxies located well beyond the Local Group. The richness of these clusters allows us to obtain large samples of post-main sequence stars and test how well the observed CMDs are reproduced by canonical stellar isochrones. Methods: We use imaging of seven clusters in the galaxies NGC 1313, NGC 1569, NGC 1705, NGC 5236 and NGC 7793 obtained with the Advanced Camera for Surveys on board the Hubble Space Telescope and carry out PSF-fitting photometry of individual stars in the clusters. The clusters have ages in the range ~(5-50) × 106 years and masses of ~105 M?-106 M?. Although crowding prevents us from obtaining photometry in the inner regions of the clusters, we are still able to measure up to 30-100 supergiant stars in each of the richest clusters. The resulting CMDs and luminosity functions are compared with photometry of artificially generated clusters, designed to reproduce the photometric errors and completeness as realistically as possible. Results: In agreement with previous studies, our CMDs show no clear gap between the H-burning main sequence and the He-burning supergiant stars, contrary to predictions by common stellar isochrones. In general, the isochrones also fail to match the observed number ratios of red-to-blue supergiant stars, although the difficulty of separating blue supergiants from the main sequence complicates this comparison. In several cases we observe a large spread (1-2 mag) in the luminosities of the supergiant stars that cannot be accounted for by observational errors. We find that this spread can be reproduced by including an age spread of ~(10-30) × 106 years in the models. However, age spreads cannot fully account for the observed morphology of the CMDs and other processes, such as the evolution of interacting binary stars, may also play a role. Conclusions: Colour-magnitude diagrams can be successfully obtained for massive star clusters out to distances of at least 4-5 Mpc. Comparing such CMDs with models based on canonical isochrones we find several areas of disagreement. One interesting possibility is that an age spread of up to ~30 Myr may be present in some clusters. The data presented here may provide useful constraints on models for single and/or binary stellar evolution. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute. STScI is operated by the association of Universities for Research in Astronomy, Inc. under the NASA contract NAS 5-26555Tables 4-10 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/532/A147

Larsen, S. S.; de Mink, S. E.; Eldridge, J. J.; Langer, N.; Bastian, N.; Seth, A.; Smith, L. J.; Brodie, J.; Efremov, Yu. N.

2011-08-01

358

A study of lubrication, processing conditions, and material combinations that affect the wear of micro-textured-carbide coated cobalt-chromium-molybdenum alloy surfaces used for artificial joints implants  

NASA Astrophysics Data System (ADS)

Total joint replacement remains one of the most successful treatments for arthritis. The most common materials used for artificial joints are metals (e.g., cobalt-chrome alloys or titanium alloys), which articulate against ultra-high molecular weight polyethylene. Wear related failures of artificial joints may be reduced with the use of novel micro-textured carbide surfaces. The micro-textured carbide surfaces were deposited on a CoCrMo alloy using microwave plasma-assisted chemical vapor deposition. Wear tests were conducted to determine wear mechanisms and properties of the micro-textured surfaces. The research presented in this thesis addresses: (1) rheolgoical behavior of bovine calf serum with and without antibacterial agents to determine whether they can be used as appropriate models for synovial fluid, (2) the wear behavior of the micro-textured CoCrMo surface system, and (3) the mechanical and material properties of the micro-textured CoCrMo alloy surface relevant to wear performance. The rheological studies showed that the apparent viscosity of bovine calf serum increased with an increase in concentration before and after the serum was used for wear testing. The wear analysis showed that the processing conditions (2hr deposition vs. 4hr deposition times) affected the wear properties. The 2hr carbide-on-carbide lubricated in 50% BCS produced the lowest wear factor and rate for the five wear couple systems containing the carbide disk or plate material. Greater wear was produced in serum without penicillin/streptomycin (P/S) compared to the serum containing P/S. A greater carbide coating thickness 10 (micrometers) was produced during the 4hr deposition time than for the 2hr deposition (˜3mum). The nano-hardness value was higher than the micro-hardness for both the 4hr and 2hr carbide surfaces. The micro-hardness results of the worn carbide surfaces showed that an increase in BCS concentration from 0% to 100% increased the micro-hardness (HV) for carbide surfaces (from 873 to 1344 HV).

Ettienne-Modeste, Geriel A.

359

We triggered a multi-wavelength observing campaign including radio observations at RATAN-600, millimeter observations at Plateau de Bure, optical photometry at sev-  

E-print Network

, millimeter observations at Plateau de Bure, optical photometry at sev- eral ground-based observatories, near of the catalogue. 1.2 Photometry Optical photometry is based on the detections derived from SExtractor32 , using isopho- tal corrected photometry and Midas/DAOPHOT33 . The photometric calibration against the reference

Cai, Long

360

Photometry and Spectroscopy of BD+35 1111 in M38  

NASA Astrophysics Data System (ADS)

BD+35 1111 is a ~10.5-magnitude star in the field of M38, an open cluster that has been a target of our ongoing study of H? emission variability in massive stars via narrowband CCD photometry (e.g. Souza, Davis, and Teich 2013, BAAS. 45, PM354.22). BD+35 1111 has no MKK classification in the literature, and is not listed as variable in GCVS, VSX, or NSVS. It is included, with no further characterization, in both the Vatican and Kohoutek catalogs of emission line stars. Using inhomogeneous ensemble photometry (e.g. Bhatti, Richmond, Ford, and Petro 2010, ApJ Supp., 186, 233), we find it to be an irregular variable with a range of ~0.15 mag. To further understand this star we obtained a medium-resolution spectrum using the DIS spectrograph on the ARC 3.5-meter telescope at Apache Point Observatory. We classify BD+35 1111 as B2Ve, the only confirmed Be star in the field of M38. This raises the question of membership, since the age of M38 is likely 250 Ma or greater (Pandey et al. 2007, Publ. Astron. Soc. Japan 59, 547). From published B and V magnitudes we find a nominal distance to BD+35 1111 of 1.6 kpc, but with a range of 1.3 to 2.0 kpc, marginally consistent with distance estimates for M38 ranging from 1.0 to 1.4 kpc. If a member, BD+35 1111 is a candidate blue straggler. If not, it may have escaped from a nearby younger cluster, possibly Kronberger 1 (Kronberger et al. 2006, A&A 447, 921), which has the right heliocentric distance and age. The notion that BD+35 1111 is behind M38 is supported by its reddening of EB-V ~ 0.5, significantly higher than for M38 itself 0.24). We gratefully acknowledge support for student research from NSF grant AST-1005024 to the Keck Northeast Astronomy Consortium, Williams College, and NASA via an American Astronomical Society Small Research Grant.

Souza, Steven P.; Kwitter, Karen B.; Sami, Mona; Beltz-Mohrmann, Gillian

2014-06-01

361

Photometry of Two Intense Low Mass X-Ray Binaries  

NASA Astrophysics Data System (ADS)

The intense galactic X-ray source GX349+2 (Sco X-2) belongs to the class of persistently bright low-mass X-ray binaries called Z-sources. GX349+2 has only recently been optically identified with a 19th mag star. Of the six known Z-sources, only two (Sco X-1 and Cyg X-2) have been studied in the optical. It has been suggested that Z-sources as a group are characterized by evolved companions and correspondingly long orbital periods (Sco X-1, P=0.8d; Cyg X-2, P=9.8d). Recently Southwell et al. have presented spectroscopic observations of GX349+2 suggesting a 14d orbital period. We have obtained broadband photometry of the system on six consecutive nights in May 1995, and find evidence for a 21.7 +/- 0.3hr period of 0.14 mag half-amplitude, superposed on erratic flickering typical of Sco X-1 type objects. As with other Z-sources, caution will be needed to insure that the variations are truly periodic, and not simply due to chaotic variability observed over a relatively short time span. If our period is confirmed, then the nature of the 14d spectroscopic variation found by Southwell et al. is unclear. GX13+1 is a bright X-ray burst source, located in the galactic bulge. Due to heavy obscuration, no optical counterpart brighter than R ~ 22 has been detected, but an infrared counterpart (K=12) has recently been identified by Naylor et al. (1991) based on spatial coincidence with an accurate radio position. GX13+1 is unusual as there is a disagreement over its classification. Studies of the X-ray time variability place it among the Atoll-sources. However, there is some evidence that the system contains a giant companion (Garcia et al. 1992) which would place it among the Z-sources. In an attempt to determine the period of the system, we observed GX13+1 for 9 days in May -- July 1995. Preliminary photometry confirms variability of ~ 0.4 mag on a timescale of several days, as previously discovered by Charles & Naylor (1992). If GX13+1 is found to have a large orbital period, it would be indicative of a giant companion, and thus challenge the distinction between Atoll- and Z-sources on the basis of orbital and evolutionary characteristics.

Wachter, S.; Margon, B.; Anderson, S.

1995-12-01

362

DDO Photometry of M71: Carbon and Nitrogen Patterns Among Evolving Giants  

E-print Network

We present V, B-V, and DDO C(41-42) and C(42-45) photometry for a sample of 75 red giants down to M_V = +2 in the relatively metal-rich Galactic globular cluster M71. The C(41-42) colors reveal a bimodal distribution of CN band strengths generally anticorrelated with CH band strength as measured by the C(42-45) color. Both DDO colors agree well with those found in 47 Tucanae -- a nearby globular cluster of similar metallicity -- and suggest nearly identical C and N abundance patterns among the giants of both clusters. A comparison with synthetic DDO colors demonstrates that little change in surface C or N abundance is required to match the colors of the M71 giants over the entire luminosity range observed. Apparently like 47 Tuc (a cluster of much greater mass and central concentration), M71 exhibits an abundance pattern which cannot be solely the result of internal mixing.

M. M. Briley; G. H. Smith; C. F. Claver

2001-08-07

363

Photometry of the SW Sex-type nova-like BH Lyncis in high state  

E-print Network

Aims: We present a photometric study of the deeply eclipsing SW Sex-type nova-like cataclysmic variable star BH Lyn Methods: Time-resolved V-band CCD photometry was obtained for seven nights between 1999 and 2004. Results: We determined 11 new eclipse timings of BH Lyn and derived a refined orbital ephemeris with an orbital period of 0.155875577(14) day. During the observations, BH Lyn was in high-state with V~15.5 mag. The star presents ~1.5 mag deep eclipses with mean full-width at half-flux of 0.0683(+/-0.0054)P_orb. The eclipse shape is highly variable, even changing form cycle to cycle. This is most likely due to accretion disc surface brightness distribution variations, most probably caused by strong flickering. Time-dependent accretion disc self-occultation or variations of the hot spot(s) intensity are also possible explanations. Negative superhumps with period of ~0.145 day are detected in two long runs in 2000. A possible connection between SW Sex and negative superhump phenomena through the presence of tilted accretion disc is discussed, and a way to observationally test this is suggested.

V. Stanishev; Z. Kraicheva; V. Genkov

2007-04-10

364

SOAP: A Tool for the Fast Computation of Photometry and Radial Velocity Induced by Stellar Spots  

NASA Astrophysics Data System (ADS)

Dark spots and bright plages are present on the surface of dwarf stars from spectral types F to M, even in their low-active phase (like the Sun). Their appearance and disappearance on the stellar photosphere, combined with the stellar rotation, may lead to errors and uncertainties in the characterization of planets both in radial velocity (RV) and photometry. Spot Oscillation and Planet (SOAP) is a tool offered to the community that enables to simulate spots and plages on rotating stars and computes their impact on RV and photometric measurements. This tool will help to understand the challenges related to the knowledge of stellar activity for the next decade: detect telluric planets in the habitable zone of their stars (from G to M dwarfs), understand the activity in the low-mass end of M dwarf (on which future projects, like SPIRou or CARMENES, will focus), limitation to the characterization of the exoplanetary atmosphere (from the ground or with Spitzer, JWST), search for planets around young stars. These can be simulated with SOAP in order to search for indices and corrections to the effect of activity.

Boisse, I.; Bonfils, X.; Santos, N. C.; Figueira, P.

2013-04-01

365

VizieR Online Data Catalog: VI photometry of the Leo II galaxy (Bellazzini+, 2005)  

NASA Astrophysics Data System (ADS)

V and I photometry and astrometry for 2715 stars in a 9.4'x9.4' field centered on the Leo II dwarf spheroidal galaxy. Photometric system: Johnson-Kron-Cousins (Landolt's photometric standards). (1 data file).

Bellazzini, M.; Gennari, N.; Ferraro, F. R.

2005-06-01

366

Spectroscopy and photometry of the nova M31N 2015-01a  

NASA Astrophysics Data System (ADS)

We report optical spectroscopy and photometry of the recent M31 nova M31N 2015-01a first detected by MASTER (ATel #6911) and also observed spectrally (ATels #6924, #6941, #6952) and photometrically (MASTER, ATel #6951).

Fabrika, S.; Barsukova, E. A.; Valeev, A. F.; Vinokurov, A.; Sholukhova, O.; Goranskij, V. P.; Hornoch, K.; Henze, M.; Shafter, A. W.

2015-01-01

367

Precision of a Low-Cost InGaAs Detector for Near Infrared Photometry  

E-print Network

We have designed, constructed, and tested an InGaAs near-infrared camera to explore whether low-cost detectors can make small (?1 m) telescopes capable of precise (photometry of relatively bright targets. ...

Simcoe, Robert A.

368

VizieR Online Data Catalog: Photometry in 6 galactic open star clusters (Glushkova+, 2010)  

NASA Astrophysics Data System (ADS)

We present the results of our BVRcIc CCD photometry for six Galactic open star clusters toward the Perseus spiral arm performed at the Special Astrophysical Observatory of the Russian Academy of Sciences. (7 data files).

Glushkova, E. V.; Zabolotskikh, M. V.; Koposov, S. E.; Spiridonova, O. I.; Vlasuk, V. V.; Rastorguev, A. S.

2010-04-01

369

A survey for post-common-envelope binary stars using GALEX and SDSS photometry  

Microsoft Academic Search

We report the first results of our programme to obtain multi-epoch radial velocity measurements of stars with a strong far-ultraviolet excess to identify post-common-envelope binaries (PCEBs). The targets have been identified using optical photometry from Sloan Digital Sky Survey (SDSS) DR4, ultraviolet photometry from Galaxy Evolution Explorer (GALEX) GR2 and proper motion information from SDSS DR5. We have obtained spectra

P. F. L. Maxted; B. T. Gänsicke; M. R. Burleigh; J. Southworth; T. R. Marsh; R. Napiwotzki; G. Nelemans; P. L. Wood

2009-01-01

370

NEOWISE Studies of Asteroids with Sloan Photometry: Preliminary Results  

NASA Astrophysics Data System (ADS)

We have combined the NEOWISE and Sloan Digital Sky Survey data to study the albedos of 24,353 asteroids with candidate taxonomic classifications derived using Sloan photometry. We find a wide range of moderate to high albedos for candidate S-type asteroids that are analogous to the S complex defined by previous spectrophotometrically based taxonomic systems. The candidate C-type asteroids, while generally very dark, have a tail of higher albedos that overlaps the S types. The albedo distribution for asteroids with a photometrically derived Q classification is extremely similar to those of the S types. Asteroids with similar colors to (4) Vesta have higher albedos than the S types, and most have orbital elements similar to known Vesta family members. Finally, we show that the relative reflectance at 3.4 and 4.6 ?m is higher for D-type asteroids and suggest that their red visible and near-infrared spectral slope extends out to these wavelengths. Understanding the relationship between size, albedo, and taxonomic classification is complicated by the fact that the objects with classifications were selected from the visible/near-infrared Sloan Moving Object Catalog, which is biased against fainter asteroids, including those with lower albedos.

Mainzer, A.; Masiero, J.; Grav, T.; Bauer, J.; Tholen, D. J.; McMillan, R. S.; Wright, E.; Spahr, T.; Cutri, R. M.; Walker, R.; Mo, W.; Watkins, J.; Hand, E.; Maleszewski, C.

2012-01-01

371

CCD Photometry of the W UMa type star QX Andromeda  

NASA Astrophysics Data System (ADS)

We present new B- and V-band photometry of the W UMa-type binary system QX And, which is a member of the open cluster NGC 752. Revised orbital period and new ephemerides were given for the binary system based on the data of times of light minima. The result of a period analysis reveals that the system is undergoing a continuous orbital period increase during the past decades. The rate of period increasing turns out to be about 2.7 × 10 -7 d yr -1. With the Wilson-Devinney code, a photometric solution is computed. It yields a contact configuration for the system with a filling factor of 0.361. Combining the results from the photometric solution along with that from the radial-velocity observations, we have determined the absolute parameters for the two components of the system. The masses, radii and luminosity of the primary and secondary stars are calculated as 1.43 ± 0.04 M?, 1.45 ± 0.09 R?, 2.87 ± 0.40 L? and 0.44 ± 0.02 M?, 0.87 ± 0.05 R?, 0.99 ± 0.13 L?, respectively. The evolutionary status and physical nature of the contact binary system were discussed compared with the theoretical models.

Ren, A. B.; Zhang, X. B.; Luo, C. Q.; Luo, Y. P.; Deng, L. C.; Luo, Z. Q.

2011-04-01

372

Worldwide photometry of the January 1989 Tau Persei eclipse  

NASA Technical Reports Server (NTRS)

New UBV photoelectric photometry of Tau Persei obtained at 19 different observatories during its recent January 1989 eclipse is presented. Mideclipse occurred at JD 2 447 542.31 + or - 0.01. The resulting light curve, though not complete at all phases, is solved for the elements with the help of two quantities derived from spectroscopy: the eclipse is 84 percent total at mideclipse, and the ratio of the radii is 0.135 + or - 0.01. Radii relative to the semimajor axis are 0.0236 for the G5 giant and 0.0032 for the A2 star. With a reasonable total mass assumed, the absolute radii say the A2 star could be luminosity class V or somewhat evolved and the G5 star is between III and II but could be closer to II. The G5 giant is brighter than the A2 star by 1.72 mag in V and the color excess in B - V is 0.06 mag, both quantities consistent (within uncertainties) with earlier estimates of Ake (1986). The eclipse duration, from first to fourth contact, is 2.09 day. The orbital inclination is 88.74 deg, consistent with what McAlister derived from speckle interferometry. Because of the large (e = 0.73) eccentricity, there is no secondary eclipse at all.

Hall, Douglas S.; Curott, David R.; Barksdale, William S.; Diethelm-Sutter, Roger; Ells, Jack

1991-01-01

373

IRSF SIRIUS JHKs Simultaneous Transit Photometry of GJ 1214b  

NASA Astrophysics Data System (ADS)

We report on the high-precision transit photometry of GJ 1214b in JHKs bands simultaneously taken with the SIRIUS camera on the Infrared Survey Facility 1.4 m telescope located in Sutherland, South Africa. Our Markov-Chain Monte Carlo analysis shows that observed planet-to-star radius ratios in the JHKs bands are Rp/Rs,J = 0.11833 ± 0.00077, Rp/Rs,H = 0.11522 ± 0.00079, and Rp/Rs,Ks = 0.11459 ± 0.00099, respectively. The radius ratios are very consistent with previous studies by Bean et al. (2011, ApJ, 743, 92) within 1 ?, while our ratio in the Ks band is shallower than previous measurements in the same band by Croll et al. (2011, ApJ, 736, 78) and inconsistent even at the 4? level with them. We have no satisfactory explanation for this discrepancy at this point. Our overall results support a flat transmission spectrum in the observed bands, which can be explained by a water-dominated atmosphere or an atmosphere with extensive high-altitude clouds or haze. To explain the discrepancy of the radius ratios, and to determine a definitive atmosphere model for GJ 1214b in the future, more extended transit observations in around the Ks band would be especially important.

Narita, Norio; Nagayama, Takahiro; Suenaga, Takuya; Fukui, Akihiko; Ikoma, Masahiro; Nakajima, Yasushi; Nishiyama, Shogo; Tamura, Motohide

2013-04-01

374

First CCD photometry for the contact binary VZ Trianguli  

NASA Astrophysics Data System (ADS)

First CCD photometry is presented for the eclipsing binary VZ Trianguli, observed at the Sheshan Station of Shanghai Astronomical Observatory in 2008. Using the Wilson-Devinney Code, the photometric solution of VZ Tri was first deduced from the R-band observations. The results show that VZ Tri is an A-subtype late-type contact binary, with a mass ratio of q=0.350(±0.004) and a low contact degree of f=27.9%(±1.0%). Based on all available light minimum times covering over 40 years, it is found that the orbital period shows a long-term decrease at a rate of dP/ dt=-1.52(±0.03)×10-7 d yr-1, suggesting that VZ Tri is undergoing mass transfer from the more massive component to the less massive component, accompanied with angular momentum loss. With period decreasing, the inner and outer critical Roche lobes will shrink, and then cause the contact degree to increase. Therefore, the weak-contact binary VZ Tri with decreasing period may evolve into a deep-contact configuration.

Yang, Y.-G.

2010-03-01

375

Stromgren $u$ Photometry of CH Cygni in 1995 and 1996  

NASA Astrophysics Data System (ADS)

Rapid time-resolution, Stromgren u-band photometry of CH cygni shows a marked decrease in quasi-periodic, short time scale ( ~ 2000--3000 s) variability between 1995 August and 1996 June. In 1995, we detected variability of ~ 0.3--0.4 mag with periods of ~2200 s and ~2700 s, which are remarkably similar to periods reported by Hoard (1993) from similar u-band measurements of CH Cyg in 1992. In contrast, during a number of nights in 1996 the u magnitude was roughly constant within 0.1 mag, and the light curves showed no evidence of rapid variability. The average u magnitude of CH Cyg decreased by ~ 0.9 mag between 1995 and 1996, suggesting a common source for the quasi-periodic variability and the u-band luminosity, namely the hot component in the interacting binary. We discuss several possible explanations for this variability, including the spin of an accreting, magnetic white dwarf (as in the intermediate polar class of cataclysmic variables) and the reprocessing of accretion-induced radiation from the white dwarf in circumstellar material. (SECTION: Stars)

Rodgers, B.; Hoard, D. W.; Burdullis, T.; Machado-Pelaez, L.; O'Toole, M.; Reed, S.

1997-10-01

376

Time-Resolved Photometry of V458 Vul  

NASA Astrophysics Data System (ADS)

We observed V458 Vul (Nova Vul 2007) over four nights in June, 2010, nearly three years after its nova outburst. Time-resolved photometry was obtained at the Vatican Advanced Technology Telescope (VATT) on Mt. Graham, Arizona, covering 2 to 4 hour spans with a cadence of 30 sec. The first night of data shows a clear 20 minute periodicity with a 0.1 magnitude amplitude. On subsequent nights, power-spectral analysis continues to show variations with a time scale of 20 minutes, but the irregularity of the signal suggests that this is a quasi-periodic oscillation. The 98-minute orbital period is not evident in our observations. V458 Vul is the central star of a planetary nebula. Combining our CCD images suggests a light echo from the nova outburst is scattering off of material in the nebula to the northwest of the central star. Appreciation goes to the National Science Foundation for supporting this project through the Research Experience for Undergraduates program at Notre Dame.

Bouzid, Samia; Garnavich, P.

2011-01-01

377

Vilnius Multicolor CCD Photometry of the Open Cluster NGC 752  

NASA Astrophysics Data System (ADS)

We have performed multicolor CCD observations of the central area of NGC 752 to search for faint, low-mass members of this open cluster. Four 12'x12' fields were taken on the 1.8 m Vatican Advanced Technology Telescope (Mt. Graham, Arizona) using a 4K CCD camera and eight intermediate-band filters of the Strömvil system. In this paper we present a catalog of photometry for 405 stars down to the limiting magnitude V=18.5, which contains V magnitudes and color indices of the Vilnius system, together with photometric determinations of spectral types, absolute magnitudes MV, interstellar reddening values EY-V and metallicity parameters [Fe/H]. The good quality multicolor data made it possible to identify the locus of the lower main sequence to four magnitudes beyond the previous (photographic) limit. A relatively small number of photometric members identified at faint magnitudes seems to be indicative of actual dissolution of the cluster from the low-mass end.

Bartaši?t?, S.; Janusz, R.; Boyle, R. P.; Philip, A. G. Davis

378

Performance of Electroluminescent Flats for Precision Light Curve Photometry  

NASA Astrophysics Data System (ADS)

We measure of the quality of flat field frames (flats) taken using an electroluminescent (EL) panel versus both dome and sky flats for purposes of calibrating visual CCD images. Classic dome and sky flats can both suffer from overall gradients and local irregularities. EL panel flats have recently grown in popularity as a third alternative, based partly on their potential to be free of such defects. We assess the flats based on their contributions to the RMS noise of long-duration light curves constructed via differential aperture photometry. The noise levels explored range from ~ 1 - few mmag, as needed for the ground-based detection of transiting planets. The target and reference stars are deliberately permitted to drift across the CCD in order to probe pixel-to-pixel variations. Both the filter and focus are varied during the tests - the former to probe color variation in the flats, and the latter because defocusing tends to average out pixel-to-pixel variations that the flats are intended to remove. All tests were performed at the Westminster College Observatory (WCO), which belongs to the Kilodegree Extremely Little Telescope (KELT)-North follow-up network.

Avril, Ryan L.; Oberst, T. E.

2014-01-01

379

Infrared imaging and photometry of Comet Giacobini-Zinner  

NASA Technical Reports Server (NTRS)

Infrared images and photometry were obtained to determine the spatial distribution and physical characteristics (temperature, albedo, size distribution, total mass, etc.) of the grains in the coma of Comet GZ. A 10.8 m image of Comet GZ obtained on August 4 represents the first groundbased thermal-infrared image of a Comet. Among the most significant results are: (1)An estimate of the number of grains that the ICE spacecraft must have encountered, which led the plasma wave team to conclude that they could only detect impacts on the antennae and not on the whole body of the ICE spacecraft; (2)The discovery of a population of large grains (radius > 100 micrometer), not observed in most other comets, which formed a curved tail near the nucleus (within 80 arcsec or 34,000 km); and (3)the detection of structure in the spatial distribution in the coma of the particle albedo, which was tentatively attributed to the presence of very fluffy grains which are likely to have multiple internal scattering of incident sunlight. The albedo map of Comet GZ was obtained by combining the 10.8 micrometer image shown with a simultaneous image taken at 0.68 micrometer, a bandpass which isolates the scattered continuum.

Campins, H.

1986-01-01

380

Optical Photometry of SN 1993J: Years 1995 to 2003  

E-print Network

In this paper, the late-time optical photometry of supernova (SN) 1993J in M81 from Feburary 1995 to Janurary 2003 is presented. The observations were performed in a set of intermediate-band filters that have the advantage of tracing the strength variations of some spectral features. SN 1993J was found to fade very slowly at late times, declining only by $0.05\\pm0.02$ mag 100 d$^{-1}$ in most of the filters from 2 to nearly 10 yrs after discovery. Our data suggest that the circumstellar interaction provides most of the energy to power the late-time optical emission of SN 1993J. This is manifested by several flux peaks seen in the rough spectral energy distributions constructed from the multicolor light curves. The flux peaks near 6600 \\AA, 5800 \\AA{} and 4900 \\AA{} may correspond to the emission lines of H$\\alpha$, Na I D + He I $\\lambda$5876 and [O III] $\\lambda\\lambda$4959, 5007, respectively. The evolution of these emission lines suggest a power-law SN density model as proposed by \\citet{cf94}.

Tianmeng Zhang; Xiaofeng Wang; Xu Zhou; Weidong Li; Jun Ma; Zhaoji Jiang; Zongwei Li

2004-06-25

381

HUBBLE SPACE TELESCOPE PHOTOMETRY OF GLOBULAR CLUSTERS IN M81  

SciTech Connect

We perform aperture photometry and profile fitting on 419 globular cluster (GC) candidates with m{sub V} {<=} 23 mag identified in Hubble Space Telescope/Advanced Camera for Surveys BVI imaging, and estimate the effective radii of the clusters. We identify 85 previously known spectroscopically confirmed clusters, and newly identify 136 objects as good cluster candidates within the 3{sigma} color and size ranges defined by the spectroscopically confirmed clusters, yielding a total of 221 probable GCs. The luminosity function peak for the 221 probable GCs with estimated total dereddening applied is V {approx} (20.26 {+-} 0.13) mag, corresponding to a distance of {approx}3.7 {+-} 0.3 Mpc. The blue and red GC candidates, and the metal-rich and metal-poor spectroscopically confirmed clusters, respectively, are similar in half-light radius. Red confirmed clusters are about 6% larger in median half-light radius than blue confirmed clusters, and red and blue good GC candidates are nearly identical in half-light radius. The total population of confirmed and 'good' candidates shows an increase in half-light radius as a function of galactocentric distance.

Nantais, Julie B. [Departamento de Astronomia, Universidad de Concepcion Av. Esteban Iturra s/n Barrio Universitario Casilla 160-C Concepcion (Chile); Huchra, John P.; Zezas, Andreas; Gazeas, Kosmas; Strader, Jay [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2011-12-15

382

BRITE-Constellation: nanosatellites for precision photometry of bright stars  

E-print Network

BRITE-Constellation (where BRITE stands for BRIght Target Explorer) is an international nanosatellite mission to monitor photometrically, in two colours, the brightness and temperature variations of stars generally brighter than mag(V) ~ 4, with precision and time coverage not possible from the ground. The current mission design consists of six nanosats (hence Constellation): two from Austria, two from Canada, and two from Poland. Each 7 kg nanosat carries an optical telescope of aperture 3 cm feeding an uncooled CCD. One instrument in each pair is equipped with a blue filter, the other with a red filter. Each BRITE instrument has a wide field of view (~24 degrees), so up to about 15 bright stars can be observed simultaneously, sampled in 32 pixel x 32 pixel sub-rasters. Photometry of additional fainter targets, with reduced precision but thorough time sampling, will be possible through onboard data processing. The BRITE sample is dominated by the most intrinsically luminous stars: massive stars seen at all e...

Weiss, W W; Moffat, A F J; Schwarzenberg-Czerny, A; Koudelka, O F; Grant, C C; Zee, R E; Kuschnig, R; Mochnacki, St; Matthews, J M; Orleanski, P; Pamyatnykh, A; Pigulski, A; Alves, J; Guedel, M; Handler, G; Wade, G A; Zwintz, K; CCD,

2014-01-01

383

SYNMAG PHOTOMETRY: A FAST TOOL FOR CATALOG-LEVEL MATCHED COLORS OF EXTENDED SOURCES  

SciTech Connect

Obtaining reliable, matched photometry for galaxies imaged by different observatories represents a key challenge in the era of wide-field surveys spanning more than several hundred square degrees. Methods such as flux fitting, profile fitting, and PSF homogenization followed by matched-aperture photometry are all computationally expensive. We present an alternative solution called 'synthetic aperture photometry' that exploits galaxy profile fits in one band to efficiently model the observed, point-spread-function-convolved light profile in other bands and predict the flux in arbitrarily sized apertures. Because aperture magnitudes are the most widely tabulated flux measurements in survey catalogs, producing synthetic aperture magnitudes (SYNMAGs) enables very fast matched photometry at the catalog level, without reprocessing imaging data. We make our code public and apply it to obtain matched photometry between Sloan Digital Sky Survey ugriz and UKIDSS YJHK imaging, recovering red-sequence colors and photometric redshifts with a scatter and accuracy as good as if not better than FWHM-homogenized photometry from the GAMA Survey. Finally, we list some specific measurements that upcoming surveys could make available to facilitate and ease the use of SYNMAGs.

Bundy, Kevin; Yasuda, Naoki [Kavli Institute for the Physics and Mathematics of the Universe, Todai Institutes for Advanced Study, the University of Tokyo (Kavli IPMU, WPI), Kashiwa 277-8583 (Japan); Hogg, David W. [Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Higgs, Tim D.; Nichol, Robert C.; Masters, Karen L. [Institute for Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Burnaby Road, Portsmouth PO1 3FX (United Kingdom); Lang, Dustin [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Wake, David A. [Department of Astronomy, Yale University, New Haven, CT 06520-8101 (United States)

2012-12-01

384

SYNMAG Photometry: A Fast Tool for Catalog-level Matched Colors of Extended Sources  

NASA Astrophysics Data System (ADS)

Obtaining reliable, matched photometry for galaxies imaged by different observatories represents a key challenge in the era of wide-field surveys spanning more than several hundred square degrees. Methods such as flux fitting, profile fitting, and PSF homogenization followed by matched-aperture photometry are all computationally expensive. We present an alternative solution called "synthetic aperture photometry" that exploits galaxy profile fits in one band to efficiently model the observed, point-spread-function-convolved light profile in other bands and predict the flux in arbitrarily sized apertures. Because aperture magnitudes are the most widely tabulated flux measurements in survey catalogs, producing synthetic aperture magnitudes (SYNMAGs) enables very fast matched photometry at the catalog level, without reprocessing imaging data. We make our code public and apply it to obtain matched photometry between Sloan Digital Sky Survey ugriz and UKIDSS YJHK imaging, recovering red-sequence colors and photometric redshifts with a scatter and accuracy as good as if not better than FWHM-homogenized photometry from the GAMA Survey. Finally, we list some specific measurements that upcoming surveys could make available to facilitate and ease the use of SYNMAGs.

Bundy, Kevin; Hogg, David W.; Higgs, Tim D.; Nichol, Robert C.; Yasuda, Naoki; Masters, Karen L.; Lang, Dustin; Wake, David A.

2012-12-01

385

Variables Affecting Earth's Albedo  

NSDL National Science Digital Library

Earth's albedo is the fraction of incoming radiation (sunlight) that is reflected into space. The Earth has an average albedo, which describes how much sunlight is reflected on average for the whole planet and the whole year. The Earth also has a local albedo, which determines how much of the Sun's light is reflected from a particular place at a particular time. The local albedo depends on the particular local surface, which can change seasonally as vegetation changes. It also depends on more rapidly changing things such as snow and clouds. In this lesson, students will investigate one of the variables that affect the Earth's albedo. They will collect and graph data on Earth's albedo from two surface types at the same latitude over a period of two years. They will then use the data to calculate how much difference there is in Earth's albedo between the two locations and suggest reasons for the differences.

386

Precision Near-Infrared Photometry for Exoplanet Transit Observations. I. Ensemble Spot Photometry for an All-Sky Survey  

NASA Astrophysics Data System (ADS)

Near-IR observations are important for the detection and characterization of exoplanets using the transit technique, either in surveys of large numbers of stars or for follow-up spectroscopic observations of individual planets. In a controlled laboratory experiment, we imaged ˜104 critically sampled spots onto an Teledyne Hawaii-2RG (H2RG) detector to emulate an idealized star field. We obtained time-series photometry of up to ?24 hr duration for ensembles of ˜103 pseudostars. After rejecting correlated temporal noise caused by various disturbances, we measured a photometric performance of less than 50 ppm hr-1/2 limited only by the incident photon rate. After several hours we achieved a photon-noise-limited precision level of 10--20 ppm after averaging many independent measurements. We conclude that IR detectors such as the H2RG can make the precision measurements needed to detect the transits of terrestrial planets or to detect faint atomic or molecular spectral features in the atmospheres of transiting extrasolar planets.

Clanton, C.; Beichman, C.; Vasisht, G.; Smith, R.; Gaudi, B. S.

2012-07-01

387

Uncovering Multiple Populations in Globular Clusters with Washington Photometry  

NASA Astrophysics Data System (ADS)

Globular Clusters (GCs), long considered as ideal Simple Stellar Populations, are now known to harbor a wide variety of chemical inhomogeneities. Multiple populations (MP) are being found in a growing number of Galactic globular clusters (GCs) via both photometric and spectroscopic techniques. Indeed, it has been suggested that a GC is an object that possesses MP. A definitive investigation of MP in GCs will undoubtedly provide a profound improvement in our understanding of their formation and evolution.However, most studies employ either high resolution VLT spectroscopy, HST photometry or inefficient filters from the ground. A ground-based photometric system which is both efficient and effective would be especially excellent for uncovering MP. We demonstrate that the Washington system meets these goals. The Washington C filter, in addition to being specifically designed for the purpose of detecting MPs, is both much broader and redder than competing UV filters, making it far more efficient at detecting MPs and much less sensitive to reddening and extinction.Our analysis of the well-studied GC NGC 1851 shows indeed that the C filter is both very efficient and effective at detecting its previously discovered MPs in the RGB and SGB, using relatively little telescope time on only a 1-meter telescope. Remarkably, we have also detected an intrinsically broad MS best characterized by two distinct but heavily overlapping populations that cannot be explained by binaries, field stars, or photometric errors. Detailed analysis shows that the MS distribution is in very good agreement with that seen on the RGB. This is the first time MPs in a MS have been discovered from the ground, and just as strikingly, using only a 1-meter telescope. The Washington system thus proves to be a very powerful tool for investigating MPs, and holds particular promise for extragalactic objects where photons are limited.

Geisler, Douglas; Cummings, Jeff; Villanova, Sandro; Carraro, Giovanni

2015-01-01

388

Campaign Photometry During The 2010 Eclipse Of Epsilon Aurigae  

NASA Astrophysics Data System (ADS)

Epsilon Aurigae is a long period (27.1 years) eclipsing binary star system with an eclipse that lasts nearly 2 years, but with severe ambiguities about component masses and shape. The current eclipse began on schedule in August of 2009. During the previous, 1982-1984 eclipse, an International Campaign was formed to coordinate a detailed study of the system. While that Campaign was deemed successful, the evolutionary status of the star system remained unclear. Epsilon Aurigae has been observed nearly continuously since the 1982 eclipse. The current Campaign was officially started in 2006. In addition to a Yahoo forum we have a dedicated web site and more than 18 online newsletters reporting photometry, spectroscopy, interferometry and polarimetry data. High quality UBVRIJH band photometric data since before the start of the current eclipse has been submitted. We explore the color differences among the light curves in terms of eclipse phases and archival data. At least one new model of the star system has been proposed since the current Campaign began: a low mass but very high luminosity F star plus a B star surrounded by a debris disk. The current eclipse and in particular the interferometry and spectroscopic data have caused new thoughts on defining eclipsing variable star contact points and phases of an eclipse. Second contact may not be the same point as start of totality and third contact may not be the same point as the start of egress and end of totality. In addition, the much awaited mid-eclipse brightening may or may not have appeared. This paper identifies the current Campaign contributors and the photometric data. This work was supported in part by the bequest of William Herschel Womble in support of astronomy at the University of Denver, by NSF grant 1016678 to the University of Denver.

Hopkins, Jeff; Stencel, R. E.

2011-01-01

389

Stromvil Photometry of Clusters. 1. The Globular Cluster M 5  

NASA Astrophysics Data System (ADS)

The Stromvil Photometric system was devised by Strai\\v{z}ys et al. (1996) to create photometric system that would allow the classification of stars by temperature, luminosity and metallicity types even in regions of high interstellar reddening. It is a combination of Stromgren and Vilnius photometry, employing the four filters of the Stromgren system and filters S, Z and P of the Vilnius system. Observations in the new system are being carried out at the Vatican Advanced Technology Telescope on Mt. Graham, Arizona. This paper reports on preliminary results of photometric measures made in the globular cluster, M 5. Using the VATT CCD, a 2k by 2k Loral chip with high quantum efficiency, even in the ultraviolet, the telescope images an area of six arcminutes square. This allowed us to image the central region of M 5 as well as the less populated areas surrounding the core. At the present time the y and b filters have been processed allowing us to prepare a color-magnitude diagram for the cluster. As in the case for M 92, a group of blue stars were found below the horizontal branch by about 0.5 mag. The majority of these stars are located in the cluster core. The next step in the reduction process is to reduce the u and v frames so the c1 index can be computed. In M 92, the stars below the BHB fell below the ZAMS in the c1, (b-y) diagram, confirming their lower luminosity and it will be interesting to see if this is true in M 5 as well. REFERENCE Strai\\v{z}ys, V., Crawford, D. L. & Philip, A. G. D. 1996 Baltic Astronomy 5, 83

Philip, A. G. Davis; Boyle, R. P.; Straižys, V.

1998-12-01

390

The AGB population in IC 1613 using JHK photometry  

NASA Astrophysics Data System (ADS)

Context. A member of the Local Group, IC 1613 is a gas rich irregular dwarf galaxy that appears to have formed stars continuously over the last 10 Gyr and is relatively independent of external influences from other galaxies. Aims: This paper aims to study the spatial distribution of the asymptotic giant branch (AGB) population in IC 1613 and its metallicity. Methods: Using WFCAM on UKIRT, high quality JHK photometry of an area of 0.8 deg2 centered on IC 1613 was obtained. The data have been used to isolate the C- and M-type components of the AGB population and using their number ratio, C/M, a global mean metallicity has been derived. The metallicity and the tip of the red giant branch magnitude (TRGB) have been studied as a function of distance from the galactic centre and as a function of azimuthal angle. Results: The TRGB has been found to be at K0 = 18.25 ± 0.15 mag. The colour separation between the C- and M-type components of the AGB population has been located at (J - K)0 = 1.15 ± 0.05 mag, giving a global C/M ratio of 0.52 ± 0.04 and from this an iron abundance of [Fe/H] = -1.26 ± 0.07 dex has been calculated. Conclusions: The AGB population has been detected out to a radial distance of 4.5 kpc in the de-projected plane of the galaxy. The measured TRGB is consistent with previous measurements and no significant variation is detected in the TRGB or in metallicity either with galactocentric distance or azimuthal angle. Full Tables 1 and 2 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/573/A84

Sibbons, L. F.; Ryan, S. G.; Irwin, M.; Napiwotzki, R.

2015-01-01

391

SECONDARY ECLIPSE PHOTOMETRY OF WASP-4b WITH WARM SPITZER  

SciTech Connect

We present photometry of the giant extrasolar planet WASP-4b at 3.6 and 4.5 {mu}m taken with the Infrared Array Camera on board the Spitzer Space Telescope as part of Spitzer's extended warm mission. We find secondary eclipse depths of 0.319% {+-} 0.031% and 0.343% {+-} 0.027% for the 3.6 and 4.5 {mu}m bands, respectively, and show model emission spectra and pressure-temperature profiles for the planetary atmosphere. These eclipse depths are well fit by model emission spectra with water and other molecules in absorption, similar to those used for TrES-3 and HD 189733b. Depending on our choice of model, these results indicate that this planet has either a weak dayside temperature inversion or no inversion at all. The absence of a strong thermal inversion on this highly irradiated planet is contrary to the idea that highly irradiated planets are expected to have inversions, perhaps due the presence of an unknown absorber in the upper atmosphere. This result might be explained by the modestly enhanced activity level of WASP-4b's G7V host star, which could increase the amount of UV flux received by the planet, therefore reducing the abundance of the unknown stratospheric absorber in the planetary atmosphere as suggested in Knutson et al. We also find no evidence for an offset in the timing of the secondary eclipse and place a 2{sigma} upper limit on |ecos {omega}| of 0.0024, which constrains the range of tidal heating models that could explain this planet's inflated radius.

Beerer, Ingrid M.; Knutson, Heather A. [Department of Astronomy, University of California at Berkeley, Berkeley, CA 94720 (United States); Burrows, Adam [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 05844 (United States); Fortney, Jonathan J.; Laughlin, Gregory [Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States); Agol, Eric; Cowan, Nicolas B. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Charbonneau, David; Desert, Jean-Michel [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Deming, Drake [Planetary Systems Laboratory, NASA's Goddard Space Flight Center, Greenbelt MD 20771 (United States); Langton, Jonathan [Department of Physics, Principia College, Elsah, IL 62028 (United States); Lewis, Nikole K.; Showman, Adam P. [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States)

2011-01-20

392

Spitzer Transit and Secondary Eclipse Photometry of GJ 436b  

E-print Network

We report the results of infrared (8 micron) transit and secondary eclipse photometry of the hot Neptune exoplanet, GJ436b using Spitzer. The nearly photon-limited precision of these data allow us to measure an improved radius for the planet, and to detect the secondary eclipse. The transit (centered at HJD = 2454280.78149 +/-0.00016) shows the flat-bottomed shape typical of infrared transits, and it precisely defines the planet-to-star radius ratio (0.0839 +/-0.0005), independent of the stellar properties. However, we obtain the planetary radius, as well as the stellar mass and radius, by fitting to the transit curve simultaneously with an empirical mass-radius relation for M-dwarfs (M=R). We find Rs=Ms=0.47 +/-0.02 in solar units, and Rp=27,600 +/-1170 km (4.33 +/-0.18 Earth radii). This radius significantly exceeds the radius of a naked ocean planet, and requires a gasesous hydrogen-helium envelope. The secondary eclipse occurs at phase 0.587 +/-0.005, proving a significant orbital eccentricity (e=0.15 +/-0.012). The amplitude of the eclipse (5.7 +/-0.8e-4) indicates a brightness temperature for the planet of T=712 +/-36K. If this is indicative of the planet's physical temperature, it suggests the occurrence of tidal heating in the planet. An uncharacterized second planet likely provides ongoing gravitational perturbations, to maintain GJ436b's orbit eccentricity over long time scales.

Drake Deming; Joseph Harrington; Gregory Laughlin; Sara Seager; Sarah B. Navarro; William C. Bowman; Karen Horning

2007-07-18

393

Rotational Modulation and Flares on Rs-Canum and By-Draconis Stars - Part Seventeen - Ultraviolet Spectroscopy and Optical Photometry of Au-Microscopii in 1986  

NASA Astrophysics Data System (ADS)

We present IUE spectroscopy and optical photometry of the active late type star AU Mic. The UV spectroscopy allow us to measure the chromospheric and transition region line fluxes. No detectable variations attributable to rotational modulation were evident in either the chromospheric lines or optical bands. We have produced an emission measure curve for the quiescent state of AU Mic, which spans a temperature range 4.0 ? log Te ? 7.6 when coupled with previous X-ray flux measurements. The quiescent radiative losses per unit surface area over the above temperature range is ?8 1O7 erg cm-2 s-1

Quin, D. A.; Doyle, J. G.; Butler, C. J.; Byrne, P. B.; Swank, J. H.

1993-05-01

394

VizieR Online Data Catalog: RIJHK photometry of VLM objects near eps Ori (Scholz+, 2005)  

NASA Astrophysics Data System (ADS)

Coordinates and photometry of very low mass objects near epsilon Ori are presented. The RIJHK photometry of these objects is consistent with membership of the young Ori OB Ib association. Time series observations of this region were carried out using the ESO/MPG WFI at the 2.2-m telescope on La Silla, from 18 to 22 December 2001. In the framework of this monitoring campaign, we obtained deep Cousins R- and I-band images, from which we derived coordinates (columns 2 and 3) as well as photometry in the R- and I-band (columns 4 and 5). Additional near-infrared photometry in J, H, K comes from the 2MASS database (columns 6--8). The cluster member selection is based on a (I,R-I) colour magnitude diagram. The (J-H) colours were used to reject contaminating field stars. The masses given in column 9 were estimated by comparing the near-infrared photometry with the evolutionary tracks of Baraffe et al. (1998A&A...337..403B), assuming an age of 5Myr. (1 data file).

Scholz, A.; Eisloffel, J.

2004-09-01

395

Near-nucleus photometry of comets using archived NEAT data  

NASA Astrophysics Data System (ADS)

Though optimized to discover and track fast moving Near-Earth Objects (NEOs), the Near-Earth Asteroid Tracking (NEAT) survey dataset can be mined to obtain information on the comet population observed serendipitously during the asteroid survey. We have completed analysis of over 400 CCD images of comets obtained during the autonomous operations of two 1.2-m telescopes: the first on the summit of Haleakala on the Hawaiian island of Maui and the second on Palomar Mountain in southern California. Photometric calibrations of each frame were derived using background catalog stars and the near-nucleus comet photometry measured. We measured dust production and normalized magnitudes for the coma and nucleus in order to explore cometary activity and comet size-frequency distributions. Our data over an approximately two-year time frame (2001 August-2003 February) include 52 comets: 12 periodic, 19 numbered, and 21 non-periodic, obtained over a wide range of viewing geometries and helio/geocentric distances. Nuclear magnitudes were estimated for a subset of comets observed. We found that for low-activity comets ( Af?<100 cm) our model gave reasonable estimates for nuclear size and magnitude. The slope of the cumulative luminosity function of our sample of low-activity comets was 0.33 ± 0.04, consistent with the slope we measured for the Jupiter-family cometary nuclei collected by Fernández et al. [Fernández, J.A., Tancredi, G., Rickman, H., Licandro, J., 1999. Astron. Astrophys. 392, 327-340] of 0.38 ± 0.02. Our slopes of the cumulative size distribution ?=1.50±0.08 agree well with the slopes measured by Whitman et al. [Whitman, K., Morbidelli, A., Jedicke, R., 2006. Icarus 183, 101-114], Meech et al. [Meech, K.J., Hainaut, O.R., Marsden, B.G., 2004. Icarus 170, 463-491], Lowry et al. [Lowry, S.C., Fitzsimmons, A., Collander-Brown, S., 2003. Astron. Astrophys. 397, 329-343], and Weissman and Lowry [Weissman, P.R., Lowry, S.C., 2003. Lunar Planet. Sci. 34. Abstract 34].

Hicks, Michael D.; Bambery, Raymond J.; Lawrence, Kenneth J.; Kollipara, Priya

2007-06-01

396

Extreme ultraviolet spectroscopy and photometry of VV Puppis during a high accretion state  

NASA Technical Reports Server (NTRS)

We determine the physical properties of the accretion region of the AM Her-type binary VV Puppis using extreme ultraviolet (EUV) medium-resolution spectroscopy and photometry obtained with the Extreme Ultraviolet Explorer (EUVE) observatory. The EUV continuum from VV Pup was detected in the wavelength range from 75 to 135 A and was simultaneously recorded with the Deep Survey/Spectrometer (DS/S) imaging telescope, allowing for the extraction of an accurate light curve. VV Pup appeared to have entered a high-accretion state just prior to the pointed EUVE observations. We use the EUV light curve to infer the diameter of the accretion region (d = 220 km) assuming a hemispherical geometry and a radius of 9000 km for the white dwarf. We perform a model atmosphere analysis and, based on the light curve properties and assuming a distance of 145 pc, we derive an effective temperature of the accretion region in the range 270,000 is less than T(sub eff) is less than 360,000 K and a neutral hydrogen column density in the local interstellar medium of n(sub H) = 1.9 - 3.7 x 10(exp 19)/sq cm. The total EUV/soft X-ray energy radiated by the accretion region is approximately 3.5 x 10(exp 32) ergs/s. Our results provide a first verification of past suggestions that deep heating of the white dwarf surface produces the soft X-ray flux from the polars. We present a possible detection of O VI absortion features, and we suggest that extensive EUVE observations targeting high-accretion events may result in oxygen and heavier element abundance determination in the accretion region.

Vennes, Stephane; Szkody, Paula; Sion, Edward M.; Long, Knox S.

1995-01-01

397

TIME-SERIES BVI PHOTOMETRY FOR THE GLOBULAR CLUSTER NGC 6981 {sup ,} {sup ,}  

SciTech Connect

We present new BVI photometry of the globular cluster NGC 6981, based mostly on ground-based CCD archival images. We present a new color-magnitude diagram (CMD) that reaches almost four magnitudes below the turn-off level. We performed new derivations of metallicity and morphological parameters of the evolved sequences, in good agreement with the results of previous authors, and obtain a value of [Fe/H] ? –1.50 in the new UVES scale. We also identify the cluster's blue straggler population. Comparing the radial distribution of these stars with the red giant branch population, we find that the blue stragglers are more centrally concentrated, as found in previous studies of blue stragglers in globular clusters. Taking advantage of the large field of view covered by our study, we analyzed the surface density profile of the cluster, and find extratidal main sequence stars out to r ? 14.'1, or about twice the tidal radius. We speculate that the presence of these stars may be due to tidal disruption in the course of NGC 6981's orbit, in which case tidal tails associated with the cluster may exist. We also take a fresh look at the variable stars in the cluster, recovering all previously known variables, including three SX Phoenicis stars. We also add three previously unknown RR Lyrae (one c-type and two ab-type) to the total census. Finally, comparing our CMD with unpublished data for M3 (NGC 5272), a cluster with a similar metallicity and horizontal branch morphology, we found that both objects are essentially coeval.

Amigo, P.; Catelan, M.; Zoccali, M. [Pontificia Universidad Católica de Chile, Instituto de Astrofísica, Av. Vicuña Mackenna 4860, 782-0436 Macul, Santiago (Chile); Stetson, P. B. [Dominion Astrophysical Observatory, Herzberg Institute of Astrophysics, National Research Council, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Smith, H. A., E-mail: mcatelan@astro.puc.cl, E-mail: mzoccali@astro.puc.cl, E-mail: pia.amigo@dfa.uv.cl, E-mail: Peter.Stetson@nrc-cnrc.gc.ca, E-mail: smith@pa.msu.edu [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)

2013-11-01

398

Multicolor Photometry and Time-resolved Spectroscopy of Two sdBV Stars  

NASA Astrophysics Data System (ADS)

Observational mode constraints have mostly been lacking for short period pulsating sdB stars, yet such identifications are vital to constrain models. Time-resolved spectroscopy and multicolor photometry have been employed with mixed results for short-period pulsating sdB stars. Time-resolved spectroscopy has successfully measured radial velocity, temperature, and gravity variations in six pulsators, yet interpreting results is far from straightforward. Multicolor photometry requires extremely high precision to discern between low-degree modes, yet has been used effectively to eliminate high-degree modes. Combining radial velocity (RV) and multicolor measurements has also been shown as an effective means of constraining mode identifications. We present preliminary results for Feige 48 and EC 01541-1409 using both time-resolved spectroscopy and multicolor photometry and an initial examination of their pulsation modes using the atmospheric codes BRUCE and KYLIE.

Reed, M. D.; O'Toole, S. J.; Telting, J. H.; Østensen, R. H.; Heber, U.; Barlow, B. N.; Reichart, D. E.; Nysewander, M. C.; LaCluyze, A. P.; Ivarsen, K. M.; Haislip, J. B.; Bean, J.

2012-03-01

399

Investigating spatial variation in the surface and atmosphere of Pluto through stellar occultations and PSF photometry  

E-print Network

Stellar occultations provide a high-resolution view of a single chord through Pluto's atmosphere. This thesis presents three projects related to stellar occultation observations of Pluto. The first project concerns the ...

Zangari, Amanda Marie

2013-01-01

400

NGC 4314. II - Hubble Space Telescope I-band surface photometry of the nuclear region  

NASA Technical Reports Server (NTRS)

We present an HST I-band Planetary Camera image of the nuclear region of NGC 4314, an anemic barred galaxy with recent star formation confined to a nuclear ring. These data resolve the nuclear ring into multiple sites of new star formation and resolve associated dust lanes into discrete clouds. Deconvolution results in at least 0.13 arcsec resolution, as demonstrated by the de Vaucouleurs r exp 1/4 law. Contrasted with similar studies of M87 and NGC 7457, we find no photometric evidence for an extreme concentration of stars in the center of NGC 4314. We identify an oval distortion of length 8 arcsec in the nuclear region, using ellipse-fitting routines and the unsharp masked frame. This nuclear bar has newer stars near its ends. We catalog 14 star clusters associated with H II regions in the nuclear ring. As an additional demonstration of the resolution achieved, the integral size distribution of these clusters is described by an exponential relationship which prevails down to 0.14 arcsec.

Benedict, G. F.; Higdon, J. L.; Jefferys, W. H.; Duncombe, R.; Hemenway, P. D.; Shelus, P. J.; Whipple, A. L.; Nelan, E.; Story, D.; Mcarthur, B.

1993-01-01

401

VizieR Online Data Catalog: Multiband surface photometry of 21 BCGs (Micheva+ 2013)  

NASA Astrophysics Data System (ADS)

The data consist of optical and NIR broadband imaging (UBVRIHKs), obtained during the period 2003-2007 with ALFOSC (at the Nordic Optical Telescope, NOT, La Palma), MOSCA (NOT), and EMMI (at the European Southern Observatory New Technology Telescope, ESO NTT, La Silla) in the optical, and with NOTCAM (NOT) and SOFI (ESO NTT) in the NIR. Very deep observations are of a volume-limited sample of 21 Blue Compact Galaxies (Emission line galaxies). The images are reduced (bias correction, flatfielding, normalized, aligned, skysubtracted). Calibration to the Vega photometric system in the optical based on Landolt standard stars; in the NIR on 2MASS field stars found in each frame. Total exposure time (seconds) in each filter and galaxy is included in each FITS header as TOTALTIM. Cosmic rays have not been removed. (4 data files).

Micheva, G.; Ostlin, G.; Zackrisson, E.; Bergvall, N.; Marquart, T.; Masegosa, J.; Marquez, I.; Cumming, R. J.; Durret, F.

2013-07-01

402

Optical Surface Photometry of a Sample of Disk Galaxies. II Structural Components  

E-print Network

This work presents the structural decomposition of a sample of 11 disk galaxies, which span a range of different morphological types. The U, B, V, R, and I photometric information given in Paper I (color and color-index images and luminosity, ellipticity, and position-angle profiles) has been used to decide what types of components form the galaxies before carrying out the decomposition. We find and model such components as bulges, disks, bars, lenses and rings.

M. Prieto; J. A. L. Aguerri; A. M. Varela; C. Muñoz-Tuñón

2000-12-05

403

Precision of a Low-Cost InGaAs Detector for Near Infrared Photometry  

NASA Astrophysics Data System (ADS)

We have designed, constructed, and tested an InGaAs near-infrared camera to explore whether low-cost detectors can make small (? 1 m) telescopes capable of precise (< 1 mmag) infrared photometry of relatively bright targets. The camera is constructed around the 640 × 512 pixel APS640C sensor built by FLIR Electro-Optical Components. We designed custom analog-to-digital electronics for maximum stability and minimum noise. The InGaAs dark current halves with every 7°C of cooling, and we reduce it to 840 e- s-1 pixel-1 (with a pixel-to-pixel variation of ± 200 e- s-1 pixel-1) by cooling the array to -20°C. Beyond this point, glow from the readout dominates. The single-sample read noise of 149 e- is reduced to 54 e- through up-the-ramp sampling. Laboratory testing with a star field generated by a lenslet array shows that two-star differential photometry is possible to a precision of 631 ± 205 ppm (0.68 mmag) hr-1/2 at a flux of 2.4 × 104 e- s-1. Employing three comparison stars and decorrelating reference signals further improves the precision to 483 ± 161 ppm (0.52 mmag) hr-1/2. Photometric observations of HD80606 and HD80607 (J = 7.7 and 7.8) in the Y band shows that differential photometry to a precision of 415 ppm (0.45 mmag) hr-1/2 is achieved with an effective telescope aperture of 0.25 m. Next-generation InGaAs detectors should indeed enable Poisson-limited photometry of brighter dwarfs with particular advantage for late-M and L types. In addition, one might acquire near-infrared photometry simultaneously with optical photometry or radial velocity measurements to maximize the return of exoplanet searches with small telescopes.

Sullivan, Peter W.; Croll, Bryce; Simcoe, Robert A.

2013-09-01

404

FAINT NEAR-ULTRAVIOLET/FAR-ULTRAVIOLET STANDARDS FROM SWIFT/UVOT, GALEX, AND SDSS PHOTOMETRY  

SciTech Connect

At present, the precision of deep ultraviolet photometry is somewhat limited by the dearth of faint ultraviolet standard stars. In an effort to improve this situation, we present a uniform catalog of 11 new faint (u {approx} 17) ultraviolet standard stars. High-precision photometry of these stars has been taken from the Sloan Digital Sky Survey and Galaxy Evolution Explorer archives and combined with new data from the Swift Ultraviolet Optical Telescope to provide precise photometric measures extending from the near-infrared to the far-ultraviolet. These stars were chosen because they are known to be hot (20, 000 < T{sub eff} < 50, 000 K) DA white dwarfs with published Sloan spectra that should be photometrically stable. This careful selection allows us to compare the combined photometry and Sloan spectroscopy to models of pure hydrogen atmospheres to both constrain the underlying properties of the white dwarfs and test the ability of white dwarf models to predict the photometric measures. We find that the photometry provides good constraints on white dwarf temperatures, which demonstrates the ability of Swift/UVOT to investigate the properties of hot luminous stars. We further find that the models reproduce the photometric measures in all 11 passbands to within their systematic uncertainties. Within the limits of our photometry, we find the standard stars to be photometrically stable. This success indicates that the models can be used to calibrate additional filters to our standard system, permitting easier comparison of photometry from heterogeneous sources. The largest source of uncertainty in the model fitting is the uncertainty in the foreground reddening curve, a problem that is especially acute in the UV.

Siegel, Michael H.; Hoversten, Erik A.; Roming, Peter W. A.; Brown, Peter, E-mail: siegel@astro.psu.ed, E-mail: hoversten@astro.psu.ed, E-mail: roming@astro.psu.ed, E-mail: brown@astro.psu.ed [Department of Astronomy, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States)

2010-12-10

405

Photometry and imaging of the peculiar planetary nebula IRAS 21282 + 5050  

NASA Technical Reports Server (NTRS)

We report visible, near-infrared, and mid-infrared photometry of the IRAS planetary nebula 21282+ 5050. Narrow-band photometry at 10 microns confirms the presence of the 11.3-micron PAH feature. IRAS 21282+5050 belongs to a small group of planetary nebulae with WC11 nuclei and PAH emission. The spectral energy distribution shows that majority of the flux is emitted in the infrared, and the object has one of the highest infrared excesses among all planetary nebulae. Optical imaging (after subtraction of the central star) reveals a nebula of size of about 7 x 5 arcsec which is elongated along the N-S direction.

Kwok, Sun; Hrivnak, Bruce J.; Langill, Philip P.

1993-01-01

406

VizieR Online Data Catalog: gr photometry of Sextans A and Sextans B (Bellazzini+, 2014)  

NASA Astrophysics Data System (ADS)

The tables present deep LBT/LBC g and r photometry of the stars having image quality parameters (provided by DAOPHOTII) CHI<=2 and SHARP within magnitude-dependent contours traced to include the bulk of stellar objects. The observations were achieved on the night og 2012-02-21 with the Large Binocular Camera at the Large Binocular Telescope in binocular mode; g images were acquired with the blue arm and r images with the red arm of the telescope/camera. The astrometry and the photometry were calibrated with stars in common with SDSS-DR9 (V/139). (2 data files).

Bellazzini, M.; Beccari, G.; Fraternali, F.; Oosterloo, T. A.; Sollima, A.; Testa, V.; Galleti, S.; Perina, S.; Faccini, M.; Cusano, F.

2014-04-01

407

VizieR Online Data Catalog: UBVRIJHK photometry of Dolidze 25 (Delgado+, 2010)  

NASA Astrophysics Data System (ADS)

Photometric color for 1673 stars in the direction of the young open cluster Dolidze 25. UBVRI CCD photometry, calibrated with previously published photoelectric values for some stars in the field, and the observations of standard fields. JHKs photometry, calibrated with matching to 2MASS data. The determination of cluster distance, reddening and age is carried out through comparison with ZAMS, post-MS and PMS isochrones. The reference lines used are obtained from theoretical post-MS and PMS isochrones from the Geneva and Yale groups, for metallicity Z=0.004, in agreement with the spectroscopic metallicity determination published for several cluster members. (1 data file).

Delgado, A. J.; Djupvik, A. A.; Alfaro, E. J.

2009-11-01

408

Disk-integrated photometry of Neptune at methane-band and continuum wavelengths  

NASA Astrophysics Data System (ADS)

The present disk-integrated photometry of Neptune, which was obtained in 1986 and 1987, is used to study the diurnal and short-term variability; the fact that this photometry was obtained from high-resolution CCD images allows the discrete cloud features' causing of the rotational lightcurve seen at methane-band wavelengths to be definitively demonstrated. A quiescent state of the Neptune atmosphere is suggested by the planet's 8900 A reflectivity in the absence of bright clouds, appears to have remained nearly constant over the observational period.

Hammel, H. B.; Lark, N. L.; Rigler, M.; Kreidl, T. J.

1989-05-01

409

The Fundamental Plane and the Surface Brightness Test for the Expansion of the Universe  

Microsoft Academic Search

We have determined the Petrosian radius, reta , and the enclosed mean surface brightness within the Petrosian radius, eta, for 33 elliptical and S0 galaxies in the Coma cluster from new accurate CCD surface photometry. For the Petrosian parameter eta = 1.39, reta and eta are compared with the effective radius, re, and the effective mean surface brightness, e derived

Per Kjaergaard; Inger Jorgensen; Mariano Moles

1993-01-01

410

Evidence from Voyager II photometry for early resurfacing of Umbriel  

NASA Astrophysics Data System (ADS)

New Voyager II albedo maps of Umbriel are presented which reveal that its surface is subdivided into low-contrast, crudely polygonal areas ranging in size from tens to hundreds of km. The largest polygons are elongate with systematically trending northeast-southwest boundaries. Some of the polygonal areas form topographic depressions several km in depth. It is suggested that this newly discovered global albedo pattern is a relic of the early tectonic disruption of Umbriel's surface.

Helfenstein, P.; Thomas, P. C.; Veverka, J.

1989-03-01

411

Cognitive, Affective, & Behavioral Neuroscience  

E-print Network

1 23 Cognitive, Affective, & Behavioral Neuroscience ISSN 1530-7026 Volume 13 Number 1 Cogn Affect Behav Neurosci (2013) 13:46-59 DOI 10.3758/s13415-012-0128-4 Affective value and associative processing

Barrett, Lisa Feldman

412

Results of near-Earth-asteroid photometry in the frame of the ASPIN programme  

NASA Astrophysics Data System (ADS)

Regular photometric observations aimed for obtaining physical properties of near-Earth asteroids (NEA) are carried out within the Asteroid Search and Photometry Initiative (ASPIN) of the International Scientific Optical Network (ISON). At present, ISON project joins 35 observation facilities in 15 countries with 80 telescopes of different class. Photometric observations of NEAs are carried out at the telescopes with apertures from 20 cm up to 2.6 m equipped with CCD cameras. The obtained lightcurves in the Johnson-Cousins photometric system or in exceptional cases in the integral light (unfiltered photometry) have typical photometric accuracy of 0.01-0.03 mag. The main targets of these observations are near-Earth asteroids as hazardous objects pose a threat for the Earth civilization. The main purpose of the observations is to study characteristics of asteroids such as rotation period, size, and shape of the body, and surface composition. The observations are aimed toward searching binary asteroids, supporting the asteroid radar observations and investigation of the YORP effect. In 2013, we have observed 40 near-Earth asteroids in more than 200 nights. The rotation periods have been determined for 14 NEAs for the first time and, for 6 NEAs, rotation periods were defined more precisely. New rotation periods have been obtained for objects from Aten group: (137805) 1999 YK_5, (329437) 2002 OA_{22}, (367943) Duende (2012 DA_{14}); Apollo: (17188) 1999 WC_2, (137126) 1999 CF_9, (163249) 2002 GT, (251346) 2007 SJ, 2013 TV_{135}; Amor: (9950) ESA, (24445) 2000 PM_8, (137199) 1999 KX_4, (285263) 1998 QE_2, (361071) 2006 AO_4, 2010 XZ_{67}, and refined for (1943) Anteros, (3361) Orpheus, (3752) Camillo, (7888) 1993 UC, (53435) 1999 VM_{40}, (68216) 2001 CV_{26}. NEAs (7888) 1993 UC and (68216) 2001 CV_{26} were found to show signs of a binary nature. To detect possible binary asteroids, we observe the object during several consecutive nights and at several observatories located at different longitudes. In particular, to cover a long time interval and not to miss the eclipse/occultation minima, the binary NEA (285263) 1998 QE_2 has been observed in close dates in Ukraine, Georgia, Tajikistan, Mongolia, the Far East of Russia, and Mexico. To test an influence of the YORP effect on the spin rates, the lightcurves of NEAs (2100) Ra-Shalom, 88710 2001 SL_9, and (138852) 2000 WN_{10} have been obtained. The observations of small NEAs (with diameters smaller 200 m) have revealed very fast rotating NEAs with rotation periods smaller than 2.2 hours for (363305) 2002 NV_{16}, 2000 KA, and 2013 QR_1. Many of our targets were also the targets of the radar observations in the Arecibo and the Goldstone. The obtained results will be presented and the perspectives of the ASPIN programme will be discussed.

Krugly, Y.; Molotov, I.; Inasaridze, R.; Kvaratskhelia, O.; Aivazyan, V.; Rumyantsev, V.; Belskaya, I.; Golubaev, A.; Sergeev, A.; Shevchenko, V.; Slyusarev, I.; Burkhonov, O.; Ehgamberdiev, S.; Elenin, L.; Voropaev, V.; Koupianov, V.; Gaftonyuk, N.; Baransky, A.; Irsmambetova, T.; Litvinenko, E.; Aliev, A.; Namkhai, T.

2014-07-01

413

The X-shaped Milky Way bulge in OGLE-III photometry and in N-body models  

NASA Astrophysics Data System (ADS)

We model the split red clump of the Galactic bulge in OGLE-III photometry, and compare the results to predictions from two N-body models. Our analysis yields precise maps of the brightness of the two red clumps, the fraction of stars in the more distant peak, and their combined surface density. We compare the observations to predictions from two N-body models previously used in the literature. Both models correctly predict several features as long as one assumes an angle ?Bar ? 30° between the Galactic bar's major axis and the line of sight to the Galactic Centre. In particular that the fraction of stars in the faint red clump should decrease with increasing longitude. The biggest discrepancies between models and data are in the rate of decline of the combined surface density of red clump stars towards negative longitudes and of the brightness difference between the two red clumps towards positive longitudes, with neither discrepancy exceeding ˜25 per cent in amplitude. Our analysis of the red giant luminosity function also yields an estimate of the red giant branch bump parameters towards these high-latitude fields, and evidence for a high rate (˜25 per cent) of disc contamination in the bulge at the colour and magnitude of the red clump, with the disc contamination rate increasing towards sightlines further distant from the plane.

Nataf, David M.; Udalski, Andrzej; Skowron, Jan; Szyma?ski, Micha? K.; Kubiak, Marcin; Pietrzy?ski, Grzegorz; Soszy?ski, Igor; Ulaczyk, Krzysztof; Wyrzykowski, ?ukasz; Poleski, Rados?aw; Athanassoula, E.; Ness, Melissa; Shen, Juntai; Li, Zhao-Yu

2015-02-01

414

arXiv:1404.3440v1[astro-ph.IM]13Apr2014 CCD photometry of bright stars using objective wire mesh  

E-print Network

arXiv:1404.3440v1[astro-ph.IM]13Apr2014 CCD photometry of bright stars using objective wire mesh ; accepted #12;­ 2 ­ ABSTRACT Obtaining accurate photometry of bright stars from the ground remains tricky for precision CCD photometry of such stars. Our tests on Cep and its comparison star differing by 5 magnitudes

Masci, Frank

415

R. Astron. 345, 795--799 (2003) Five nights intensive R and Vband photometry of QSO 0957+561A,B  

E-print Network

Mon. R. Astron. 345, 795--799 (2003) Five nights intensive R­ and V­band photometry of QSO 0957 2003 Received 2003 original form May ABSTRACT present V­band photometry gravitational lens system 0957 monitoring at the Nordic Optical Telescope. In the photometry scheme have stressed careful magnitude

Ovaldsen, Jan-Erik

416

TOWARD MORE PRECISE PHOTOMETRIC REDSHIFTS: CALIBRATION VIA CCD PHOTOMETRY ROBERT J. BRUNNER, 1,2 ANDREW J. CONNOLLY, 1 AND ALEXANDER S. SZALAY 1  

E-print Network

TOWARD MORE PRECISE PHOTOMETRIC REDSHIFTS: CALIBRATION VIA CCD PHOTOMETRY ROBERT J. BRUNNER, 1 redshift, luminosity, and spectral type (Connolly et al. 1995). Using recently acquired deep CCD photometry­dimensional magnitude space. Furthermore, from our CCD photometry and the published redshifts, we have quantified

Bershady, Matthew A.

417

Astronomy 337: Instructions for... PhotVis: A Photometry and Visualization Application in IDL  

E-print Network

Astronomy 337: Instructions for... PhotVis: A Photometry and Visualization Application in IDL Rob a recommendation, I often go to 7-sigma or lower and visually filter out spurious detections. Too low examination and sorting: (a) Sort through your objects, using the visualization tools. Once you have valid

Lowenthal, James D.

418

Unveiling the nature of red novae cool explosions using archive plate photometry  

E-print Network

Based on archive photographic photometry and recent CCD photometric data for red novae V4332 Sgr and V838 Mon, we established their stellar composition, exploded components, and the nature of explosions. Low temperature in the outburst maximum is due to quasi-adiabatic expansion of a massive stellar envelope after the central energy surge preceded the outburst.

Goranskij, Vitaly; Zharova, Alla; Shugarov, Sergei; Barsukova, Elena; Kroll, Peter

2015-01-01

419

Characterization of Branched Poly (vinyl Acetate) by GPC and Low Angle Laser Light Scattering Photometry  

Microsoft Academic Search

Poly (vinyl acetate), PVAC, synthesized by bulk polymerization over a range of initiator concentrations ([AIBN] = 10 to 4 × 10 g-mole\\/1), temperatures (50°C, 60°C, 70°C, and 80°C) and conversion levels (3 to > 90%) were characterized using low angle laser light scattering (LALLS) photometry to measure Mw of the whole polymers. A number of these samples were characterized using

A. E. Hamielec; A. C. Ouano; L. L. Nebenzahl

1978-01-01

420

Size exclusion chromatography-low angle laser light scattering photometry of lignite macromolecules  

Microsoft Academic Search

The determination of molecular weight distribution in humic acids derived from lignite has been successfully carried out by the application of size exclusion chromatography coupled with low angle laser light scattering photometry. Reduction of soluble derivatives with zinc in acetic anhydride-dimethylformamide was required to reduce the absorbance so that linear scattering response was obtained. A benzyl derivative and a methyl

E. S. Olson; J. W. Diehl

1985-01-01

421

A STUDY OF PROPERTIES OF TYPE IA SUPERNOVA AND THE CALIBRATION OF MULTIBAND PHOTOMETRY  

E-print Network

SCHOLAR Approved by: Research Advisor: Kevin Krisciunas Associate Director, Honors and Undergraduate Research: Duncan MacKenzie May 2012 Major: Physics Mathematics iii ABSTRACT A Study... of Properties of Type Ia Supernova and the Calibration of Multiband Photometry. (May 2012) Deepak Bastola Department of Physics and Astronomy Department of Mathematics Texas A&M University Research Advisor: Dr. Kevin Krisciunas Department...

Bastola, Deepak 1988-

2012-04-27

422

Photometry of the eclipsing cataclysmic variable SDSS J152419.33+220920.0  

NASA Astrophysics Data System (ADS)

Aims: We present new photometry of the faint (g ~ 19 mag) and poorly studied cataclysmic variable SDSS J152419.33+220920.0, analyze its light curve and provide an accurate ephemeris for this system. Methods: Time-resolved CCD differential photometry was carried out using the 1.5 m and 0.84 m telescopes at the Observatorio Astronómico Nacional at San Pedro Mártir. Results: From time-resolved photometry of the system obtained during six nights (covering more than twenty primary eclipse cycles in more than three years), we show that this binary presents a strong primary and a weak secondary modulation. Our light curve analysis shows that only two fundamental frequencies are present, corresponding to the orbital period and a modulation with twice this frequency. We determine the accurate ephemeris of the system to be HJDeclipse = 2 454 967.6750(1) + 0.06531866661(1) E. A double-hump orbital period modulation, a standing feature in several bounce-back systems at quiescence, is present at several epochs. However, we found no other evidence to support the hypothesis that this system belongs to the post-minimum orbital-period systems. Photometry described in Table 1 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/554/A25

Michel, R.; Echevarría, J.; Hernández Santisteban, J. V.

2013-06-01

423

Liverpool Telescope Optical Photometry Following the 2006 Outburst of RS Ophiuchi  

E-print Network

We present a preliminary report on the broadband optical photometry of the 2006 outburst of the recurrent nova RS Ophiuchi. These data were obtained using the robotic 2m Liverpool Telescope and cover the outburst from day 27 through day 548.

M. J. Darnley; R. A. Hounsell; M. F. Bode

2008-09-26

424

VizieR Online Data Catalog: BVRI photometry of Central Field of ? Cen (Lynga+, 1996)  

NASA Astrophysics Data System (ADS)

This is a four colour photometric study of stars in the central part of the globular cluster ? Centauri. The observations were made at Siding Spring Observatory in April 1992 with the 1m ANU telesecope; a 1024x1024CCD has been used. The photometry was reduced to the BVRI system using standards by Landolt (3 data files).

Lynga, G.

1995-08-01

425

ASTROMETRY AND NEAR-INFRARED PHOTOMETRY OF NEPTUNE'S INNER SATELLITES AND RING ARCS  

E-print Network

ASTROMETRY AND NEAR-INFRARED PHOTOMETRY OF NEPTUNE'S INNER SATELLITES AND RING ARCS Christophe, and Despina) and ring arcs of Neptune, obtained with the Hubble Space Telescope and its near-infrared camera- ing within the ring region of Neptune have a near-infrared albedo consistently low, but higher than

Schneider, Glenn

426

Macular pigment density and distribution: comparison of fundus autofluorescence with minimum motion photometry  

Microsoft Academic Search

Macular pigment (MP) distribution profiles were measured for 18 subjects using a Moreland anomaloscope modified for motion photometry. The total amount of MP within the central 7° was estimated from the distribution profile by numerical integration. Fundus autofluorescence images were obtained for eight of these subjects using a scanning laser ophthalmoscope. Peak optical density of MP increased with the total

Anthony G. Robson; Jack D. Moreland; Daniel Pauleikhoff; Tony Morrissey; Graham E. Holder; Fred W. Fitzke; Alan C Bird; Frederik J. G. M. van Kuijk

2003-01-01

427

Morphology, photometry and kinematics of N -body bars - I. Three models with different halo central concentrations  

Microsoft Academic Search

We discuss the morphology, photometry and kinematics of the bars which have formed in three N -body simulations. These have initially the same disc and the same halo-to-disc mass ratio, but their haloes have very different central concentrations. The third model includes a bulge. The bar in the model with the centrally concentrated halo (model MH) is much stronger, longer

E. Athanassoula; A. Misiriotis

2002-01-01

428

Integrated UBV Photometry of 624 Star Clusters and Associations in the Large Magellanic Cloud  

Microsoft Academic Search

We present a catalog of integrated UBV photometry of 504 star clusters and 120 stellar associations in the LMC, part of them still embedded in emitting gas. We study age groups in terms of equivalent SWB types derived from the (U-B) X (B-V) diagram. The size of the spatial distributions increases steadily with age (SWB types), whereas a difference of

E. Bica; J. J. Claria; H. Dottori; J. F. C. Santos Jr.; A. E. Piatti

1996-01-01

429

VizieR Online Data Catalog: UBVRIJHK photometry of RR Lyrae in M4 (Stetson+, 2014)  

NASA Astrophysics Data System (ADS)

Our optical observations of M4 consist of 5003 individual CCD images obtained during the course of 18 observing runs between 1994 and 2010. The infrared photometry for M4 consisted of 55 datasets from 18 observing runs between 2002 and 2012. (6 data files).

Stetson, P. B.; Braga, V. F.; Dall'Ora, M.; Bono, G.; Buonanno, R.; Ferraro, I.; Iannicola, G.; Marengo, M.; Neeley, J.

2014-11-01

430

NIR Photometry of [HB89] 0716+714 at maximum light  

NASA Astrophysics Data System (ADS)

We report on further photometry of the ongoing NIR flare of the intermediate redshift QSO [HB89]0716+714 (z=0.30) also known as CGRaBS J0721+7120, associated with the Gamma ray source 2FGLJ0721.9+7120.

Carrasco, L.; Porras, A.; Recillas, E.; Leon-Tavares, J.; Chavushyan, V.; Carraminana, A.

2015-02-01

431

Narrow-band photometry in the 1-4 micron region - Calibration and applications  

Microsoft Academic Search

It is noted that longward of 1 micron, the absolute calibration of the photometry needed for determining the energy distributions and color temperatures of cool stars has generally been based on theoretical energy distributions. A program now under way at Kitt Peak National Observatory, however, is providing direct measurements of absolute monochromatic fluxes in a set of standard stars at

R. F. Wing; C. P. Rinsland

1981-01-01

432

Absolute magnitudes for late-type dwarf stars for Sloan photometry  

E-print Network

We present a new formula for absolute magnitude determination for late-type dwarf stars as a function of (g-r) and (r-i) for Sloan photometry. The absolute magnitudes estimated by this approach are brighter than those estimated by colour-magnitude diagrams, and they reduce the luminosity function rather close to the luminosity function of Hipparcos.

S. Bilir; S. Karaali; S. Tuncel

2005-03-18

433

AN UPDATED CATALOG OF M33 CLUSTERS AND CANDIDATES: UBVRI PHOTOMETRY AND SOME STATISTICAL RESULTS  

SciTech Connect

We present UBVRI photometry for 392 star clusters and candidates in the field of M33, which are selected from the most recent star cluster catalog. In this catalog, the authors listed star clusters' parameters such as cluster positions, magnitudes, colors in the UBVRIJHK{sub s} filters, and so on. However, a large fraction of objects in this catalog do not have previously published photometry. Photometry is performed using archival images from the Local Group Galaxies Survey, which covers 0.8 deg{sup 2} along the major axis of M33. Detailed comparisons show that, in general, our photometry is consistent with previous measurements. Positions (right ascension and declination) for some clusters are corrected here. Combined with previous literature, ours constitute a large sample of M33 star clusters. Based on this cluster sample, we present some statistical results: none of the youngest M33 clusters ({approx}10{sup 7} yr) have masses approaching 10{sup 5} M{sub Sun} ; roughly half the star clusters are consistent with the 10{sup 4}-10{sup 5} M{sub Sun} mass models; the continuous distribution of star clusters along the model line indicates that M33 star clusters have been formed continuously from the epoch of the first star cluster formation until recent times; and there are {approx}50 star clusters which are overlapped with the Galactic globular clusters on the color-color diagram, and these clusters are old globular cluster candidates in M33.

Ma Jun, E-mail: majun@nao.cas.cn [National Astronomical Observatories, Chinese Academy of Sciences, A20 Datun Road, Chaoyang District, Beijing 100012 (China)

2012-08-15

434

Spitzer Photometry of WISE-Selected Brown Dwarf and Hyper-Lumninous Infrared Galaxy Candidates  

NASA Technical Reports Server (NTRS)

We present Spitzer 3.6 and 4.5 micrometer photometry and positions for a sample of 1510 brown dwarf candidates identified by the Wide-field Infrared Survey Explorer (WISE) all-sky survey. Of these, 166 have been spectroscopically classified as objects with spectral types M(1), L(7), T(146), and Y(12). Sixteen other objects are non-(sub)stellar in nature. The remainder are most likely distant L and T dwarfs lacking spectroscopic verification, other Y dwarf candidates still awaiting follow-up, and assorted other objects whose Spitzer photometry reveals them to be background sources. We present a catalog of Spitzer photometry for all astrophysical sources identified in these fields and use this catalog to identify seven fainter (4.5 m to approximately 17.0 mag) brown dwarf candidates, which are possibly wide-field companions to the original WISE sources. To test this hypothesis, we use a sample of 919 Spitzer observations around WISE-selected high-redshift hyper-luminous infrared galaxy candidates. For this control sample, we find another six brown dwarf candidates, suggesting that the seven companion candidates are not physically associated. In fact, only one of these seven Spitzer brown dwarf candidates has a photometric distance estimate consistent with being a companion to the WISE brown dwarf candidate. Other than this, there is no evidence for any widely separated (greater than 20 AU) ultra-cool binaries. As an adjunct to this paper, we make available a source catalog of 7.33 x 10(exp 5) objects detected in all of these Spitzer follow-up fields for use by the astronomical community. The complete catalog includes the Spitzer 3.6 and 4.5 m photometry, along with positionally matched B and R photometry from USNO-B; J, H, and Ks photometry from Two Micron All-Sky Survey; and W1, W2, W3, and W4 photometry from the WISE all-sky catalog.

Griffith, Roger L.; Kirkpatrick, J. Davy; Eisenhardt, Peter R. M.; Gelino, Christopher R.; Cushing, Michael C.; Benford, Dominic; Blain, Andrew; Bridge, Carrie R.; Cohen, Martin; Cutri, Roc M.; Donoso, Emilio; Jarrett, Thomas H.; Lonsdale, Carol; Mace, Gregory; Mainzer, A.; Marsh, Ken; Padgett, Deborah; Petty, Sara; Ressler, Michael E.; Skrutskie, Michael F.; Stanford, Spencer A.; Stern, Daniel; Tsai, Chao-Wei; Wright, Edward L.; Wu, Jingwen

2012-01-01

435

VizieR Online Data Catalog: COSMOS Multi-Wavelength Photometry Catalog (Capak+, 2007)  

NASA Astrophysics Data System (ADS)

The present COSMOS data were collected on a variety of telescopes and instruments, as well as from the Sloan Digital Sky Survey (SDSS) second data release (DR2) archive (u, g, r, i, z) and Hubble Space Telescope (HST, F814W). This paper covers the processing of the data obtained with Suprime-Cam on the Subaru 8.3m telescope (Bj, Vj, g+, r+, i+, z+, NB816), Megaprime on the 3.6m Canada-France-Hawaii Telescope (CFHT, u*, i*), FLAMINGOS on the Kitt Peak National Observatory (KPNO, Ks) 4m telescope, and the Infrared Side Port Imager on the Cerro Tololo Inter-American Observatory (CTIO, Ks) 4m telescope during the 2004-2005 observing season. The COSMOS I band catalog is an I band selected multi-color catalog for 2 square degrees centered on the COSMOS field at 10:00:28.6, +02:12:21. The total magnitude (SExtractor mag_auto) for a source must have an AB magnitude of less than i+<25 to appear in the archival catalog. All photometry is in the AB magnitude system and measured in a 3" aperture on PSF-matched images unless otherwise noted. A magnitude of -99 indicates a photometric measurement was not possible due to lack of data, a large number of bad pixels, or saturation. A magnitude of 99.0 indicates no detection. In the case of no detection the error given for the object is the 1 sigma limiting magnitude at the position of the source. The photometry is as measured on the images with no corrections applied. We recommend applying the magnitude offsets in the paper to obtain the best possible photometry. More details on the photometry are available in the paper. The Photometric Redshifts included in this catalog are described in Mobasher et al. (2007ApJS..172..117M) and have an accuracy of dz/(1+z)<0.031 at z<1.2 and I<24. It is important to pay attention to the flag columns at the end of the catalog. The cleanest catalog will have all flags set to 0. The photometry flags indicate the area of the photometry aperture, in square arc seconds, which is in a masked region. A flag of 1 indicates 14 percent of the aperture is masked, so any flagged object should be carefully checked. Objects with a de-blending flag set to 1 are potentially spurious and should not be used for statistical studies. However, the photometry for real sources with a de-blending flag set to 1 is good if they fall outside of masked region. (1 data file).

Capak, P.; Aussel, H.; Ajiki, M.; McCracken, H. J.; Mobasher, B.; Scoville, N.; Shopbell, P.; Taniguchi, Y.; Thompson, D.; Tribiano, S.; Sasaki, S.; Blain, A. W.; Brusa, M.; Carilli, C.; Comastri, A.; Carollo, C. M.; Cassata, P.; Colbert, J.; Ellis, R. S.; Elvis, M.; Giavalisco, M.; Green, W.; Guzzo, L.; Hasinger, G.; Ilbert, O.; Impey, C.; Jahnke, K.; Kartaltepe, J.; Kneib, J.-P.; Koda, J.; Koekemoer, A.; Komiyama, Y.; Leauthaud, A.; Lefevre, O.; Lilly, S.; Liu, C.; Massey, R.; Miyazaki, S.; Murayama, T.; Nagao, T.; Peacock, J. A.; Pickles, A.; Porciani, C.; Renzini, A.; Rhodes, J.; Rich, M.; Salvato, M.; Sanders, D. B.; Scarlata, C.; Schiminovich, D.; Schinnerer, E.; Scodeggio, M.; Sheth, K.; Shioya, Y.; Tasca, L. A. M.; Taylor, J. E.; Yan, L.; Zamorani, G.

2008-03-01

436

VizieR Online Data Catalog: COSMOS Multi-Wavelength Photometry Catalog (Capak+, 2007)  

NASA Astrophysics Data System (ADS)

The present COSMOS data were collected on a variety of telescopes and instruments, as well as from the Sloan Digital Sky Survey (SDSS) second data release (DR2) archive (u, g, r, i, z) and Hubble Space Telescope (HST, F814W). This paper covers the processing of the data obtained with Suprime-Cam on the Subaru 8.3m telescope (Bj, Vj, g+, r+, i+, z+, NB816), Megaprime on the 3.6m Canada-France-Hawaii Telescope (CFHT, u*, i*), FLAMINGOS on the Kitt Peak National Observatory (KPNO, Ks) 4m telescope, and the Infrared Side Port Imager on the Cerro Tololo Inter-American Observatory (CTIO, Ks) 4m telescope during the 2004-2005 observing season. The COSMOS I band catalog is an I band selected multi-color catalog for 2 square degrees centered on the COSMOS field at 10:00:28.6, +02:12:21. The total magnitude (SExtractor mag_auto) for a source must have an AB magnitude of less than i+<25 to appear in the archival catalog. All photometry is in the AB magnitude system and measured in a 3 arc second aperture on PSF-matched images unless otherwise noted. A magnitude of -99 indicates a photometric measurement was not possible due to lack of data, a large number of bad pixels, or saturation. A magnitude of 99.0 indicates no detection. In the case of no detection the error given for the object is the 1 sigma limiting magnitude at the position of the souce. The photometry is as measured on the images with no corrections applied. We recommend applying the magnitude offsets in the paper to obtain the best possible photometry. More details on the photometry are available in the paper. The Photometric Redshifts included in this catalog are described in Mobasher et al. (2007ApJS..172..117M) and have an accuracy of dz/(1+z)<0.031 at z<1.2 and I<24. It is important to pay attention to the flag columns at the end of the catalog. The cleanest catalog will have all flags set to 0. The photometry flags indicate the area of the photometry aperture, in square arc seconds, which is in a masked region. A flag of 1 indicates 14 percent of the aperture is masked, so any flagged object should be carefully checked. Objects with a de-blending flag set to 1 are potentially spurious and should not be used for statistical studies. However, the photometry for real sources with a de-blending flag set to 1 is good if they fall outside of masked region. (1 data file).

Capak, P.; Aussel, H.; Ajiki, M.; McCracken, H. J.; Mobasher, B.; Scoville, N.; Shopbell, P.; Taniguchi, Y.; Thompson, D.; Tribiano, S.; Sasaki, S.; Blain, A. W.; Brusa, M.; Carilli, C.; Comastri, A.; Carollo, C. M.; Cassata, P.; Colbert, J.; Ellis, R. S.; Elvis, M.; Giavalisco, M.; Green, W.; Guzzo, L.; Hasinger, G.; Ilbert, O.; Impey, C.; Jahnke, K.; Kartaltepe, J.; Kneib, J.-P.; Koda, J.; Koekemoer, A.; Komiyama, Y.; Leauthaud, A.; Lefevre, O.; Lilly, S.; Liu, C.; Massey, R.; Miyazaki, S.; Murayama, T.; Nagao, T.; Peacock, J. A.; Pickles, A.; Porciani, C.; Renzini, A.; Rhodes, J.; Rich, M.; Salvato, M.; Sanders, D. B.; Scarlata, C.; Schiminovich, D.; Schinnerer, E.; Scodeggio, M.; Sheth, K.; Shioya, Y.; Tasca, L. A. M.; Taylor, J. E.; Yan, L.; Zamorani, G.

2008-03-01

437

Low-intensity electromagnetic irradiation of 70.6 and 73 GHz frequencies enhances the effects of disulfide bonds reducer on Escherichia coli growth and affects the bacterial surface oxidation-reduction state  

SciTech Connect

Highlights: {yields} Low intensity 70.6 and 73 GHz electromagnetic irradiation (EMI) strongly suppressed Escherichia coli growth at 73 GHz and pH 7.3. {yields} Reducer DL-dithiothreitol had bactericidal effect and disturbed the SH-groups number. {yields} EMI enhanced E. coli sensitivity toward dithiothreitol. {yields} EMI decreased the SH-groups number of membrane disturbed by ATP and N,N'-dicyclohexycarbodiimide. {yields} The changed membrane oxidation-reduction state could be the primary mechanisms in EMI effects. -- Abstract: Low-intensity electromagnetic irradiation (EMI) of 70.6 and 73 GHz frequencies (flux capacity - 0.06 mW cm{sup -2}) had bactericidal effects on Escherichia coli. This EMI (1 h) exposure suppressed the growth of E. coli K-12({lambda}). The pH value (6.0-8.0) did not significantly affect the growth. The lag-phase duration was prolonged, and the growth specific rate was inhibited, and these effects were more noticeable after 73 GHz irradiation. These effects were enhanced by the addition of DL-dithiothreitol (DTT), a strong reducer of disulfide bonds in surface membrane proteins, which in its turn also has bactericidal effect. Further, the number of accessible SH-groups in membrane vesicles was markedly decreased by EMI that was augmented by N,N'-dicyclohexycarbodiimide and DTT. These results indicate a change in the oxidation-reduction state of bacterial cell membrane proteins that could be the primary membranous mechanism in the bactericidal effects of low-intensity EMI of the 70.6 and 73 GHz frequencies.

Torgomyan, Heghine [Department of Biophysics of Biology Faculty, Yerevan State University, Yerevan 0025 (Armenia)] [Department of Biophysics of Biology Faculty, Yerevan State University, Yerevan 0025 (Armenia); Trchounian, Armen, E-mail: Trchounian@ysu.am [Department of Biophysics of Biology Faculty, Yerevan State University, Yerevan 0025 (Armenia)] [Department of Biophysics of Biology Faculty, Yerevan State University, Yerevan 0025 (Armenia)

2011-10-14

438

Oberon - Color photometry from Voyager and its geological implications  

NASA Astrophysics Data System (ADS)

The surface of the Uranian satellite Oberon is characterized on the basis of ground-based and Voyager photometric observations. Disk-integrated phase-curve and disk-resolved data are presented in extensive tables, graphs, maps, and black-and-white and false-color images and discussed in terms of fits to the Hapke (1986) parameters, local variations in albedo and color, and their possible geological significance. It is found that most of the leading hemisphere is covered with dark materials like those in the crater floors, while the trailing hemisphere has patches of the dark material on a surface with a higher proportion of icy materials which are spectrally neutral.

Helfenstein, P.; Hillier, J.; Weitz, C.; Veverka, J.

1991-03-01

439

Visible Color and Photometry of Bright Materials on Vesta  

NASA Technical Reports Server (NTRS)

The Dawn Framing Camera (FC) collected images of the surface of Vesta at a pixel scale of 70 m in the High Altitude Mapping Orbit (HAMO) phase through its clear and seven color filters spanning from 430 nm to 980 nm. The surface of Vesta displays a large diversity in its brightness and colors, evidently related to the diverse geology [1] and mineralogy [2]. Here we report a detailed investigation of the visible colors and photometric properties of the apparently bright materials on Vesta in order to study their origin. The global distribution and the spectroscopy of bright materials are discussed in companion papers [3, 4], and the synthesis results about the origin of Vestan bright materials are reported in [5].

Schroder, S. E.; Li, J. Y.; Mittlefehldt, D. W.; Pieters, C. M.; De Sanctis, M. C.; Hiesinger, H.; Blewett, D. T.; Russell, C. T.; Raymond, C. A.; Keller, H. U.

2012-01-01

440

Oberon - Color photometry from Voyager and its geological implications  

NASA Technical Reports Server (NTRS)

The surface of the Uranian satellite Oberon is characterized on the basis of ground-based and Voyager photometric observations. Disk-integrated phase-curve and disk-resolved data are presented in extensive tables, graphs, maps, and black-and-white and false-color images and discussed in terms of fits to the Hapke (1986) parameters, local variations in albedo and color, and their possible geological significance. It is found that most of the leading hemisphere is covered with dark materials like those in the crater floors, while the trailing hemisphere has patches of the dark material on a surface with a higher proportion of icy materials which are spectrally neutral.

Helfenstein, Paul; Hillier, John; Weitz, Catherine; Veverka, Joseph

1991-01-01

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