Searching for white dwarfs candidates in Sloan Digital Sky Survey Data

International Nuclear Information System (INIS)

Nalezyty, Miroslaw; Majczyna, Agnieszka; Ciechanowska, Anna; Madej, Jerzy

2009-01-01

Large amount of observational spectroscopic data are recently available from different observational projects, like Sloan Digital Sky Survey. It's become more urgent to identify white dwarfs stars based on data itself i.e. without modelling white dwarf atmospheres. In particular, existing methods of white dwarfs identification presented in Kleinman et al. (2004) and in Eisenstein et al. (2006) did not allow to find all the white dwarfs in examined data. We intend to test various criteria of searching for white dwarf candidates, based on photometric and spectral features.

THE SLOAN DIGITAL SKY SURVEY CO-ADD: A GALAXY PHOTOMETRIC REDSHIFT CATALOG

International Nuclear Information System (INIS)

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

2012-01-01

We present and describe a catalog of galaxy photometric redshifts (photo-z) for the Sloan Digital Sky Survey (SDSS) Co-add Data. We use the artificial neural network (ANN) technique to calculate the photo-z and the nearest neighbor error method to estimate photo-z errors for ∼13 million objects classified as galaxies in the co-add with r 68 = 0.031. After presenting our results and quality tests, we provide a short guide for users accessing the public data.

Distribution Of Maximal Luminosity Of Galaxies In The Sloan Digital Sky Survey

CERN Document Server

Regós, E; Rácz, Z; Taghizadeh, M; Ozogany, K

2010-01-01

Extreme value statistics (EVS) is applied to the pixelized distribution of galaxy luminosities in the Sloan Digital Sky Survey (SDSS). We analyze the DR6 Main Galaxy Sample (MGS), divided into red and blue subsamples, as well as the Luminous Red Galaxy Sample (LRGS). A non-parametric comparison of the EVS of the luminosities with the Fisher-Tippett-Gumbel distribution (limit distribution for independent variables distributed by the Press-Schechter law) indicates a good agreement provided uncertainties arising both from the finite size of the samples and from the sample size distribution are accounted for.

The 13th Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-IV Survey Mapping Nearby Galaxies at Apache Point Observatory

Science.gov (United States)

Albareti, Franco D.; Allende Prieto, Carlos; Almeida, Andres; Anders, Friedrich; Anderson, Scott; Andrews, Brett H.; Aragón-Salamanca, Alfonso; Argudo-Fernández, Maria; Armengaud, Eric; Aubourg, Eric; Avila-Reese, Vladimir; Badenes, Carles; Bailey, Stephen; Barbuy, Beatriz; Barger, Kat; Barrera-Ballesteros, Jorge; Bartosz, Curtis; Basu, Sarbani; Bates, Dominic; Battaglia, Giuseppina; Baumgarten, Falk; Baur, Julien; Bautista, Julian; Beers, Timothy C.; Belfiore, Francesco; Bershady, Matthew; Bertran de Lis, Sara; Bird, Jonathan C.; Bizyaev, Dmitry; Blanc, Guillermo A.; Blanton, Michael; Blomqvist, Michael; Bolton, Adam S.; Borissova, J.; Bovy, Jo; Nielsen Brandt, William; Brinkmann, Jonathan; Brownstein, Joel R.; Bundy, Kevin; Burtin, Etienne; Busca, Nicolás G.; Orlando Camacho Chavez, Hugo; Cano Díaz, M.; Cappellari, Michele; Carrera, Ricardo; Chen, Yanping; Cherinka, Brian; Cheung, Edmond; Chiappini, Cristina; Chojnowski, Drew; Chuang, Chia-Hsun; Chung, Haeun; Cirolini, Rafael Fernando; Clerc, Nicolas; Cohen, Roger E.; Comerford, Julia M.; Comparat, Johan; Correa do Nascimento, Janaina; Cousinou, Marie-Claude; Covey, Kevin; Crane, Jeffrey D.; Croft, Rupert; Cunha, Katia; Darling, Jeremy; Davidson, James W., Jr.; Dawson, Kyle; Da Costa, Luiz; Da Silva Ilha, Gabriele; Deconto Machado, Alice; Delubac, Timothée; De Lee, Nathan; De la Macorra, Axel; De la Torre, Sylvain; Diamond-Stanic, Aleksandar M.; Donor, John; Downes, Juan Jose; Drory, Niv; Du, Cheng; Du Mas des Bourboux, Hélion; Dwelly, Tom; Ebelke, Garrett; Eigenbrot, Arthur; Eisenstein, Daniel J.; Elsworth, Yvonne P.; Emsellem, Eric; Eracleous, Michael; Escoffier, Stephanie; Evans, Michael L.; Falcón-Barroso, Jesús; Fan, Xiaohui; Favole, Ginevra; Fernandez-Alvar, Emma; Fernandez-Trincado, J. G.; Feuillet, Diane; Fleming, Scott W.; Font-Ribera, Andreu; Freischlad, Gordon; Frinchaboy, Peter; Fu, Hai; Gao, Yang; Garcia, Rafael A.; Garcia-Dias, R.; Garcia-Hernández, D. A.; Garcia Pérez, Ana E.; Gaulme, Patrick; Ge, Junqiang; Geisler, Douglas; Gillespie, Bruce; Gil Marin, Hector; Girardi, Léo; Goddard, Daniel; Gomez Maqueo Chew, Yilen; Gonzalez-Perez, Violeta; Grabowski, Kathleen; Green, Paul; Grier, Catherine J.; Grier, Thomas; Guo, Hong; Guy, Julien; Hagen, Alex; Hall, Matt; Harding, Paul; Harley, R. E.; Hasselquist, Sten; Hawley, Suzanne; Hayes, Christian R.; Hearty, Fred; Hekker, Saskia; Hernandez Toledo, Hector; Ho, Shirley; Hogg, David W.; Holley-Bockelmann, Kelly; Holtzman, Jon A.; Holzer, Parker H.; Hu, Jian; Huber, Daniel; Hutchinson, Timothy Alan; Hwang, Ho Seong; Ibarra-Medel, Héctor J.; Ivans, Inese I.; Ivory, KeShawn; Jaehnig, Kurt; Jensen, Trey W.; Johnson, Jennifer A.; Jones, Amy; Jullo, Eric; Kallinger, T.; Kinemuchi, Karen; Kirkby, David; Klaene, Mark; Kneib, Jean-Paul; Kollmeier, Juna A.; Lacerna, Ivan; Lane, Richard R.; Lang, Dustin; Laurent, Pierre; Law, David R.; Leauthaud, Alexie; Le Goff, Jean-Marc; Li, Chen; Li, Cheng; Li, Niu; Li, Ran; Liang, Fu-Heng; Liang, Yu; Lima, Marcos; Lin, Lihwai; Lin, Lin; Lin, Yen-Ting; Liu, Chao; Long, Dan; Lucatello, Sara; MacDonald, Nicholas; MacLeod, Chelsea L.; Mackereth, J. Ted; Mahadevan, Suvrath; Geimba Maia, Marcio Antonio; Maiolino, Roberto; Majewski, Steven R.; Malanushenko, Olena; Malanushenko, Viktor; Dullius Mallmann, Nícolas; Manchado, Arturo; Maraston, Claudia; Marques-Chaves, Rui; Martinez Valpuesta, Inma; Masters, Karen L.; Mathur, Savita; McGreer, Ian D.; Merloni, Andrea; Merrifield, Michael R.; Meszáros, Szabolcs; Meza, Andres; Miglio, Andrea; Minchev, Ivan; Molaverdikhani, Karan; Montero-Dorta, Antonio D.; Mosser, Benoit; Muna, Demitri; Myers, Adam; Nair, Preethi; Nandra, Kirpal; Ness, Melissa; Newman, Jeffrey A.; Nichol, Robert C.; Nidever, David L.; Nitschelm, Christian; O’Connell, Julia; Oravetz, Audrey; Oravetz, Daniel J.; Pace, Zachary; Padilla, Nelson; Palanque-Delabrouille, Nathalie; Pan, Kaike; Parejko, John; Paris, Isabelle; Park, Changbom; Peacock, John A.; Peirani, Sebastien; Pellejero-Ibanez, Marcos; Penny, Samantha; Percival, Will J.; Percival, Jeffrey W.; Perez-Fournon, Ismael; Petitjean, Patrick; Pieri, Matthew; Pinsonneault, Marc H.; Pisani, Alice; Prada, Francisco; Prakash, Abhishek; Price-Jones, Natalie; Raddick, M. Jordan; Rahman, Mubdi; Raichoor, Anand; Barboza Rembold, Sandro; Reyna, A. M.; Rich, James; Richstein, Hannah; Ridl, Jethro; Riffel, Rogemar A.; Riffel, Rogério; Rix, Hans-Walter; Robin, Annie C.; Rockosi, Constance M.; Rodríguez-Torres, Sergio; Rodrigues, Thaíse S.; Roe, Natalie; Lopes, A. Roman; Román-Zúñiga, Carlos; Ross, Ashley J.; Rossi, Graziano; Ruan, John; Ruggeri, Rossana; Runnoe, Jessie C.; Salazar-Albornoz, Salvador; Salvato, Mara; Sanchez, Sebastian F.; Sanchez, Ariel G.; Sanchez-Gallego, José R.; Santiago, Basílio Xavier; Schiavon, Ricardo; Schimoia, Jaderson S.; Schlafly, Eddie; Schlegel, David J.; Schneider, Donald P.; Schönrich, Ralph; Schultheis, Mathias; Schwope, Axel; Seo, Hee-Jong; Serenelli, Aldo; Sesar, Branimir; Shao, Zhengyi; Shetrone, Matthew; Shull, Michael; Silva Aguirre, Victor; Skrutskie, M. F.; Slosar, Anže; Smith, Michael; Smith, Verne V.; Sobeck, Jennifer; Somers, Garrett; Souto, Diogo; Stark, David V.; Stassun, Keivan G.; Steinmetz, Matthias; Stello, Dennis; Storchi Bergmann, Thaisa; Strauss, Michael A.; Streblyanska, Alina; Stringfellow, Guy S.; Suarez, Genaro; Sun, Jing; Taghizadeh-Popp, Manuchehr; Tang, Baitian; Tao, Charling; Tayar, Jamie; Tembe, Mita; Thomas, Daniel; Tinker, Jeremy; Tojeiro, Rita; Tremonti, Christy; Troup, Nicholas; Trump, Jonathan R.; Unda-Sanzana, Eduardo; Valenzuela, O.; Van den Bosch, Remco; Vargas-Magaña, Mariana; Vazquez, Jose Alberto; Villanova, Sandro; Vivek, M.; Vogt, Nicole; Wake, David; Walterbos, Rene; Wang, Yuting; Wang, Enci; Weaver, Benjamin Alan; Weijmans, Anne-Marie; Weinberg, David H.; Westfall, Kyle B.; Whelan, David G.; Wilcots, Eric; Wild, Vivienne; Williams, Rob A.; Wilson, John; Wood-Vasey, W. M.; Wylezalek, Dominika; Xiao, Ting; Yan, Renbin; Yang, Meng; Ybarra, Jason E.; Yeche, Christophe; Yuan, Fang-Ting; Zakamska, Nadia; Zamora, Olga; Zasowski, Gail; Zhang, Kai; Zhao, Cheng; Zhao, Gong-Bo; Zheng, Zheng; Zheng, Zheng; Zhou, Zhi-Min; Zhu, Guangtun; Zinn, Joel C.; Zou, Hu

2017-12-01

The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) began observations in 2014 July. It pursues three core programs: the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2), Mapping Nearby Galaxies at APO (MaNGA), and the Extended Baryon Oscillation Spectroscopic Survey (eBOSS). As well as its core program, eBOSS contains two major subprograms: the Time Domain Spectroscopic Survey (TDSS) and the SPectroscopic IDentification of ERosita Sources (SPIDERS). This paper describes the first data release from SDSS-IV, Data Release 13 (DR13). DR13 makes publicly available the first 1390 spatially resolved integral field unit observations of nearby galaxies from MaNGA. It includes new observations from eBOSS, completing the Sloan Extended QUasar, Emission-line galaxy, Luminous red galaxy Survey (SEQUELS), which also targeted variability-selected objects and X-ray-selected objects. DR13 includes new reductions of the SDSS-III BOSS data, improving the spectrophotometric calibration and redshift classification, and new reductions of the SDSS-III APOGEE-1 data, improving stellar parameters for dwarf stars and cooler stars. DR13 provides more robust and precise photometric calibrations. Value-added target catalogs relevant for eBOSS, TDSS, and SPIDERS and an updated red-clump catalog for APOGEE are also available. This paper describes the location and format of the data and provides references to important technical papers. The SDSS web site, http://www.sdss.org, provides links to the data, tutorials, examples of data access, and extensive documentation of the reduction and analysis procedures. DR13 is the first of a scheduled set that will contain new data and analyses from the planned ∼6 yr operations of SDSS-IV.

We’re Working On It: Transferring the Sloan Digital Sky Survey from Laboratory to Library

OpenAIRE

Sands, Ashley E.; Borgman, Christine L.; Traweek, Sharon; Wynholds, Laura A.

2014-01-01

This article reports on the transfer of a massive scientific dataset from a national laboratory to a university library, and from one kind of workforce to another. We use the transfer of the Sloan Digital Sky Survey (SDSS) archive to examine the emergence of a new workforce for scientific research data management. Many individuals with diverse educational backgrounds and domain experience are involved in SDSS data management: domain scientists, computer scientists, software and systems engin...

New white dwarf and subdwarf stars in the Sloan Digital Sky Survey Data Release 12

OpenAIRE

Kepler, S. O.; Pelisoli, Ingrid; Koester, Detlev; Ourique, Gustavo; Romero, Alejandra Daniela; Reindl, Nicole; Kleinman, Scot J.; Eisenstein, Daniel J.; Valois, A. Dean M.; Amaral, Larissa A.

2015-01-01

We report the discovery of 6576 new spectroscopically confirmed white dwarf and subdwarf stars in the Sloan Digital Sky Survey Data Release 12. We obtain Teff, log g and mass for hydrogen atmospherewhite dwarf stars (DAs) and helium atmospherewhite dwarf stars (DBs), estimate the calcium/helium abundances for the white dwarf stars with metallic lines (DZs) and carbon/helium for carbon-dominated spectra (DQs). We found one central star of a planetary nebula, one ultracompact helium binary (AM ...

Sloan Digital Sky Survey IV: Mapping the Milky Way, Nearby Galaxies, and the Distant Universe

Science.gov (United States)

Blanton, Michael R.; Bershady, Matthew A.; Abolfathi, Bela; Albareti, Franco D.; Allende Prieto, Carlos; Almeida, Andres; Alonso-García, Javier; Anders, Friedrich; Anderson, Scott F.; Andrews, Brett; Aquino-Ortíz, Erik; Aragón-Salamanca, Alfonso; Argudo-Fernández, Maria; Armengaud, Eric; Aubourg, Eric; Avila-Reese, Vladimir; Badenes, Carles; Bailey, Stephen; Barger, Kathleen A.; Barrera-Ballesteros, Jorge; Bartosz, Curtis; Bates, Dominic; Baumgarten, Falk; Bautista, Julian; Beaton, Rachael; Beers, Timothy C.; Belfiore, Francesco; Bender, Chad F.; Berlind, Andreas A.; Bernardi, Mariangela; Beutler, Florian; Bird, Jonathan C.; Bizyaev, Dmitry; Blanc, Guillermo A.; Blomqvist, Michael; Bolton, Adam S.; Boquien, Médéric; Borissova, Jura; van den Bosch, Remco; Bovy, Jo; Brandt, William N.; Brinkmann, Jonathan; Brownstein, Joel R.; Bundy, Kevin; Burgasser, Adam J.; Burtin, Etienne; Busca, Nicolás G.; Cappellari, Michele; Delgado Carigi, Maria Leticia; Carlberg, Joleen K.; Carnero Rosell, Aurelio; Carrera, Ricardo; Chanover, Nancy J.; Cherinka, Brian; Cheung, Edmond; Gómez Maqueo Chew, Yilen; Chiappini, Cristina; Doohyun Choi, Peter; Chojnowski, Drew; Chuang, Chia-Hsun; Chung, Haeun; Cirolini, Rafael Fernando; Clerc, Nicolas; Cohen, Roger E.; Comparat, Johan; da Costa, Luiz; Cousinou, Marie-Claude; Covey, Kevin; Crane, Jeffrey D.; Croft, Rupert A. C.; Cruz-Gonzalez, Irene; Garrido Cuadra, Daniel; Cunha, Katia; Damke, Guillermo J.; Darling, Jeremy; Davies, Roger; Dawson, Kyle; de la Macorra, Axel; Dell'Agli, Flavia; De Lee, Nathan; Delubac, Timothée; Di Mille, Francesco; Diamond-Stanic, Aleks; Cano-Díaz, Mariana; Donor, John; Downes, Juan José; Drory, Niv; du Mas des Bourboux, Hélion; Duckworth, Christopher J.; Dwelly, Tom; Dyer, Jamie; Ebelke, Garrett; Eigenbrot, Arthur D.; Eisenstein, Daniel J.; Emsellem, Eric; Eracleous, Mike; Escoffier, Stephanie; Evans, Michael L.; Fan, Xiaohui; Fernández-Alvar, Emma; Fernandez-Trincado, J. G.; Feuillet, Diane K.; Finoguenov, Alexis; Fleming, Scott W.; Font-Ribera, Andreu; Fredrickson, Alexander; Freischlad, Gordon; Frinchaboy, Peter M.; Fuentes, Carla E.; Galbany, Lluís; Garcia-Dias, R.; García-Hernández, D. A.; Gaulme, Patrick; Geisler, Doug; Gelfand, Joseph D.; Gil-Marín, Héctor; Gillespie, Bruce A.; Goddard, Daniel; Gonzalez-Perez, Violeta; Grabowski, Kathleen; Green, Paul J.; Grier, Catherine J.; Gunn, James E.; Guo, Hong; Guy, Julien; Hagen, Alex; Hahn, ChangHoon; Hall, Matthew; Harding, Paul; Hasselquist, Sten; Hawley, Suzanne L.; Hearty, Fred; Gonzalez Hernández, Jonay I.; Ho, Shirley; Hogg, David W.; Holley-Bockelmann, Kelly; Holtzman, Jon A.; Holzer, Parker H.; Huehnerhoff, Joseph; Hutchinson, Timothy A.; Hwang, Ho Seong; Ibarra-Medel, Héctor J.; da Silva Ilha, Gabriele; Ivans, Inese I.; Ivory, KeShawn; Jackson, Kelly; Jensen, Trey W.; Johnson, Jennifer A.; Jones, Amy; Jönsson, Henrik; Jullo, Eric; Kamble, Vikrant; Kinemuchi, Karen; Kirkby, David; Kitaura, Francisco-Shu; Klaene, Mark; Knapp, Gillian R.; Kneib, Jean-Paul; Kollmeier, Juna A.; Lacerna, Ivan; Lane, Richard R.; Lang, Dustin; Law, David R.; Lazarz, Daniel; Lee, Youngbae; Le Goff, Jean-Marc; Liang, Fu-Heng; Li, Cheng; Li, Hongyu; Lian, Jianhui; Lima, Marcos; Lin, Lihwai; Lin, Yen-Ting; Bertran de Lis, Sara; Liu, Chao; de Icaza Lizaola, Miguel Angel C.; Long, Dan; Lucatello, Sara; Lundgren, Britt; MacDonald, Nicholas K.; Deconto Machado, Alice; MacLeod, Chelsea L.; Mahadevan, Suvrath; Geimba Maia, Marcio Antonio; Maiolino, Roberto; Majewski, Steven R.; Malanushenko, Elena; Malanushenko, Viktor; Manchado, Arturo; Mao, Shude; Maraston, Claudia; Marques-Chaves, Rui; Masseron, Thomas; Masters, Karen L.; McBride, Cameron K.; McDermid, Richard M.; McGrath, Brianne; McGreer, Ian D.; Medina Peña, Nicolás; Melendez, Matthew; Merloni, Andrea; Merrifield, Michael R.; Meszaros, Szabolcs; Meza, Andres; Minchev, Ivan; Minniti, Dante; Miyaji, Takamitsu; More, Surhud; Mulchaey, John; Müller-Sánchez, Francisco; Muna, Demitri; Munoz, Ricardo R.; Myers, Adam D.; Nair, Preethi; Nandra, Kirpal; Correa do Nascimento, Janaina; Negrete, Alenka; Ness, Melissa; Newman, Jeffrey A.; Nichol, Robert C.; Nidever, David L.; Nitschelm, Christian; Ntelis, Pierros; O'Connell, Julia E.; Oelkers, Ryan J.; Oravetz, Audrey; Oravetz, Daniel; Pace, Zach; Padilla, Nelson; Palanque-Delabrouille, Nathalie; Alonso Palicio, Pedro; Pan, Kaike; Parejko, John K.; Parikh, Taniya; Pâris, Isabelle; Park, Changbom; Patten, Alim Y.; Peirani, Sebastien; Pellejero-Ibanez, Marcos; Penny, Samantha; Percival, Will J.; Perez-Fournon, Ismael; Petitjean, Patrick; Pieri, Matthew M.; Pinsonneault, Marc; Pisani, Alice; Poleski, Radosław; Prada, Francisco; Prakash, Abhishek; Queiroz, Anna Bárbara de Andrade; Raddick, M. Jordan; Raichoor, Anand; Barboza Rembold, Sandro; Richstein, Hannah; Riffel, Rogemar A.; Riffel, Rogério; Rix, Hans-Walter; Robin, Annie C.; Rockosi, Constance M.; Rodríguez-Torres, Sergio; Roman-Lopes, A.; Román-Zúñiga, Carlos; Rosado, Margarita; Ross, Ashley J.; Rossi, Graziano; Ruan, John; Ruggeri, Rossana; Rykoff, Eli S.; Salazar-Albornoz, Salvador; Salvato, Mara; Sánchez, Ariel G.; Aguado, D. S.; Sánchez-Gallego, José R.; Santana, Felipe A.; Santiago, Basílio Xavier; Sayres, Conor; Schiavon, Ricardo P.; da Silva Schimoia, Jaderson; Schlafly, Edward F.; Schlegel, David J.; Schneider, Donald P.; Schultheis, Mathias; Schuster, William J.; Schwope, Axel; Seo, Hee-Jong; Shao, Zhengyi; Shen, Shiyin; Shetrone, Matthew; Shull, Michael; Simon, Joshua D.; Skinner, Danielle; Skrutskie, M. F.; Slosar, Anže; Smith, Verne V.; Sobeck, Jennifer S.; Sobreira, Flavia; Somers, Garrett; Souto, Diogo; Stark, David V.; Stassun, Keivan; Stauffer, Fritz; Steinmetz, Matthias; Storchi-Bergmann, Thaisa; Streblyanska, Alina; Stringfellow, Guy S.; Suárez, Genaro; Sun, Jing; Suzuki, Nao; Szigeti, Laszlo; Taghizadeh-Popp, Manuchehr; Tang, Baitian; Tao, Charling; Tayar, Jamie; Tembe, Mita; Teske, Johanna; Thakar, Aniruddha R.; Thomas, Daniel; Thompson, Benjamin A.; Tinker, Jeremy L.; Tissera, Patricia; Tojeiro, Rita; Hernandez Toledo, Hector; de la Torre, Sylvain; Tremonti, Christy; Troup, Nicholas W.; Valenzuela, Octavio; Martinez Valpuesta, Inma; Vargas-González, Jaime; Vargas-Magaña, Mariana; Vazquez, Jose Alberto; Villanova, Sandro; Vivek, M.; Vogt, Nicole; Wake, David; Walterbos, Rene; Wang, Yuting; Weaver, Benjamin Alan; Weijmans, Anne-Marie; Weinberg, David H.; Westfall, Kyle B.; Whelan, David G.; Wild, Vivienne; Wilson, John; Wood-Vasey, W. M.; Wylezalek, Dominika; Xiao, Ting; Yan, Renbin; Yang, Meng; Ybarra, Jason E.; Yèche, Christophe; Zakamska, Nadia; Zamora, Olga; Zarrouk, Pauline; Zasowski, Gail; Zhang, Kai; Zhao, Gong-Bo; Zheng, Zheng; Zheng, Zheng; Zhou, Xu; Zhou, Zhi-Min; Zhu, Guangtun B.; Zoccali, Manuela; Zou, Hu

2017-07-01

We describe the Sloan Digital Sky Survey IV (SDSS-IV), a project encompassing three major spectroscopic programs. The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is observing hundreds of thousands of Milky Way stars at high resolution and high signal-to-noise ratios in the near-infrared. The Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey is obtaining spatially resolved spectroscopy for thousands of nearby galaxies (median z˜ 0.03). The extended Baryon Oscillation Spectroscopic Survey (eBOSS) is mapping the galaxy, quasar, and neutral gas distributions between z˜ 0.6 and 3.5 to constrain cosmology using baryon acoustic oscillations, redshift space distortions, and the shape of the power spectrum. Within eBOSS, we are conducting two major subprograms: the SPectroscopic IDentification of eROSITA Sources (SPIDERS), investigating X-ray AGNs and galaxies in X-ray clusters, and the Time Domain Spectroscopic Survey (TDSS), obtaining spectra of variable sources. All programs use the 2.5 m Sloan Foundation Telescope at the Apache Point Observatory; observations there began in Summer 2014. APOGEE-2 also operates a second near-infrared spectrograph at the 2.5 m du Pont Telescope at Las Campanas Observatory, with observations beginning in early 2017. Observations at both facilities are scheduled to continue through 2020. In keeping with previous SDSS policy, SDSS-IV provides regularly scheduled public data releases; the first one, Data Release 13, was made available in 2016 July.

A Full Year's Chandra Exposure on Sloan Digital Sky Survey Quasars from the Chandra Multiwavelength Project

Science.gov (United States)

Green, Paul J.; Aldcroft, T. L.; Richards, G. T.; Barkhouse, W. A.; Constantin, A.; Haggard, D.; Karovska, M.; Kim, D.-W.; Kim, M.; Vikhlinin, A.; Anderson, S. F.; Mossman, A.; Kashyap, V.; Myers, A. D.; Silverman, J. D.; Wilkes, B. J.; Tananbaum, H.

2009-01-01

We study the spectral energy distributions and evolution of a large sample of optically selected quasars from the Sloan Digital Sky Survey that were observed in 323 Chandra images analyzed by the Chandra Multiwavelength Project. Our highest-confidence matched sample includes 1135 X-ray detected quasars in the redshift range 0.2 3, substantially expanding the known sample. We find no evidence for evolution out to z ~ 5 for either the X-ray photon index Γ or for the ratio of optical/UV to X-ray flux αox. About 10% of detected QSOs show best-fit intrinsic absorbing columns greater than 1022 cm-2, but the fraction might reach ~1/3 if most nondetections are absorbed. We confirm a significant correlation between αox and optical luminosity, but it flattens or disappears for fainter (MB gsim -23) active galactic nucleus (AGN) alone. We report significant hardening of Γ both toward higher X-ray luminosity, and for relatively X-ray loud quasars. These trends may represent a relative increase in nonthermal X-ray emission, and our findings thereby strengthen analogies between Galactic black hole binaries and AGN. For uniformly selected subsamples of narrow-line Seyfert 1s and narrow absorption line QSOs, we find no evidence for unusual distributions of either αox or Γ.

SPATIAL ANISOTROPY OF GALAXY KINEMATICS IN SLOAN DIGITAL SKY SURVEY GALAXY CLUSTERS

International Nuclear Information System (INIS)

Skielboe, Andreas; Wojtak, Radosław; Pedersen, Kristian; Rozo, Eduardo; Rykoff, Eli S.

2012-01-01

Measurements of galaxy cluster kinematics are important in understanding the dynamical state and evolution of clusters of galaxies, as well as constraining cosmological models. While it is well established that clusters exhibit non-spherical geometries, evident in the distribution of galaxies on the sky, azimuthal variations of galaxy kinematics within clusters have yet to be observed. Here we measure the azimuthal dependence of the line-of-sight velocity dispersion profile in a stacked sample of 1743 galaxy clusters from the Sloan Digital Sky Survey (SDSS). The clusters are drawn from the SDSS DR8 redMaPPer catalog. We find that the line-of-sight velocity dispersion of galaxies lying along the major axis of the central galaxy is larger than those that lie along the minor axis. This is the first observational detection of anisotropic kinematics of galaxies in clusters. We show that the result is consistent with predictions from numerical simulations. Furthermore, we find that the degree of projected anisotropy is strongly dependent on the line-of-sight orientation of the galaxy cluster, opening new possibilities for assessing systematics in optical cluster finding.

The Sloan Digital Sky Survey Quasar Catalog. 3. Third data release

Energy Technology Data Exchange (ETDEWEB)

Schneider, Donald P.; Hall, Patrick B.; Richards, Gordon T.; Vanden Berk, Daniel E.; Anderson, Scott F.; Fan, Xiao-Hui; Jester, Sebastian; Stoughton, Chris; Strauss,; SubbaRao, Mark; Brandt, W.N.; Gunn, James E.; Yanny, Brian; Bahcall, Neta A.; Barentine, J.C.; Blanton, Michael R.; Boroski, William N.; Brewington, Howard J.; Brinkmann, J.; Brunner, Robert; Csabai, Istvan; /Penn State U., Astron. Astrophys. /York U., Canada /Princeton U. Observ. /Washington U., Seattle, Astron. Dept. /Arizona U.,

2005-03-01

We present the third edition of the Sloan Digital Sky Survey (SDSS) Quasar Catalog. The catalog consists of the 46,420 objects in the SDSS Third Data Release that have luminosities larger than M{sub i} = -22 (in a cosmology with H{sub 0} = 70 km s{sup -1} Mpc{sup -1}, {Omega}{sub M} = 0.3, and {Omega}{sub {Lambda}} = 0.7), have at least one emission line with FWHM larger than 1000 km s{sup -1} or are unambiguously broad absorption line quasars, are fainter than i = 15.0, and have highly reliable redshifts. The area covered by the catalog is {approx} 4188 deg{sup 2}. The quasar redshifts range from 0.08 to 5.41, with a median value of 1.47; the high-redshift sample includes 520 quasars at redshifts greater than four, of which 17 are at redshifts greater than five. For each object the catalog presents positions accurate to better than 0.2'' rms per coordinate, five-band (ugriz) CCD-based photometry with typical accuracy of 0.03 mag, and information on the morphology and selection method. The catalog also contains radio, near-infrared, and X-ray emission properties of the quasars, when available, from other large-area surveys. The calibrated digital spectra cover the wavelength region 3800-9200 at a spectral resolution of {approx} 2000; the spectra can be retrieved from the public database using the information provided in the catalog. A total of 44,221 objects in the catalog were discovered by the SDSS; 28,400 of the SDSS discoveries are reported here for the first time.

The Sloan Digital Sky Survey COADD: 275 deg2 of deep Sloan Digital Sky Survey imaging on stripe 82

International Nuclear Information System (INIS)

Annis, James; Soares-Santos, Marcelle; Dodelson, Scott; Hao, Jiangang; Jester, Sebastian; Johnston, David E.; Kubo, Jeffrey M.; Lampeitl, Hubert; Lin, Huan; Miknaitis, Gajus; Yanny, Brian; Strauss, Michael A.; Gunn, James E.; Lupton, Robert H.; Becker, Andrew C.; Ivezić, Željko; Fan, Xiaohui; Jiang, Linhua; Seo, Hee-Jong; Simet, Melanie

2014-01-01

We present details of the construction and characterization of the coaddition of the Sloan Digital Sky Survey (SDSS) Stripe 82 ugriz imaging data. This survey consists of 275 deg 2 of repeated scanning by the SDSS camera over –50° ≤ α ≤ 60° and –1.°25 ≤ δ ≤ +1.°25 centered on the Celestial Equator. Each piece of sky has ∼20 runs contributing and thus reaches ∼2 mag fainter than the SDSS single pass data, i.e., to r ∼ 23.5 for galaxies. We discuss the image processing of the coaddition, the modeling of the point-spread function (PSF), the calibration, and the production of standard SDSS catalogs. The data have an r-band median seeing of 1.''1 and are calibrated to ≤1%. Star color-color, number counts, and PSF size versus modeled size plots show that the modeling of the PSF is good enough for precision five-band photometry. Structure in the PSF model versus magnitude plot indicates minor PSF modeling errors, leading to misclassification of stars as galaxies, as verified using VVDS spectroscopy. There are a variety of uses for this wide-angle deep imaging data, including galactic structure, photometric redshift computation, cluster finding and cross wavelength measurements, weak lensing cluster mass calibrations, and cosmic shear measurements.

Topology Analysis of the Sloan Digital Sky Survey. I. Scale and Luminosity Dependence

Science.gov (United States)

Park, Changbom; Choi, Yun-Young; Vogeley, Michael S.; Gott, J. Richard, III; Kim, Juhan; Hikage, Chiaki; Matsubara, Takahiko; Park, Myeong-Gu; Suto, Yasushi; Weinberg, David H.; SDSS Collaboration

2005-11-01

We measure the topology of volume-limited galaxy samples selected from a parent sample of 314,050 galaxies in the Sloan Digital Sky Survey (SDSS), which is now complete enough to describe the fully three-dimensional topology and its dependence on galaxy properties. We compare the observed genus statistic G(νf) to predictions for a Gaussian random field and to the genus measured for mock surveys constructed from new large-volume simulations of the ΛCDM cosmology. In this analysis we carefully examine the dependence of the observed genus statistic on the Gaussian smoothing scale RG from 3.5 to 11 h-1 Mpc and on the luminosity of galaxies over the range -22.50meatball'' (i.e., cluster dominated) topology, while faint galaxies show a positive shift toward a ``bubble'' (i.e., void dominated) topology. The transition from negative to positive shift occurs approximately at the characteristic absolute magnitude Mr*=-20.4. Even in this analysis of the largest galaxy sample to date, we detect the influence of individual large-scale structures, as the shift parameter Δν and cluster multiplicity AC reflect (at ~3 σ) the presence of the Sloan Great Wall and an X-shaped structure that runs for several hundred megaparsecs across the survey volume.

SPIN. First Digital Protection System Feedback of experience ... ... after 30 years

International Nuclear Information System (INIS)

Kosicki, M.; Pacuta, J.; Kamga, J.; Burel, J.-P.

2010-01-01

In this lecture Mr Burel presents experience with the software SPIN - the first digital protection system feedback. After thirty years of operation, the results are positive: - System is in correct operation and still maintained with spare parts available; - No spurious trip or actuation due to the system itself. A project for modernization is prepared to replace the digital part with a new digital technology designed with today's: - Components (SPINLINE 3); - methods and tools (Software development); - Standards (EMI/RFI - qualification), in order to allow customer to add some new functional needs and to keep the system in operation for thirty more years.

DIGITAL NATIVE: A STUDY ON THE FIRST-YEAR STUDENT

Directory of Open Access Journals (Sweden)

Deny Efita Nur Rakhmawati

2015-12-01

Full Text Available The digital native generation emergent triggers the educational practitioner to develop a new way of approaching the teaching practice in the classroom. As it is claimed that this generation has a unique characteristics and way of learning. Therefore, this paper explore the experience of the first year student of English language and letters department in using technology. Students were asked about their access to, use of and preferences for a wide range of established and emerging technologies and technology based tools using a questioner developed to assess their level of digital nativity. The results show that many first year students are highly tech-savvy. However, each student’s experience on the use of technologies and tools (e.g. computers, mobile phones show considerable variation. The findings are analyzed using the Prensky’s theory on the ‘Digital Natives’ and the implications for using technology to support teaching and learning in higher education. The reported data indicate that for a range of emerging technologies were used intensively by the students. Furthermore, the majority of the respondents also claimed that they used the tools and technology to support their study. However, it is inconclusive as how the student integrate the tools and technology in their study.

An Improved Photometric Calibration of the Sloan Digital SkySurvey Imaging Data

Energy Technology Data Exchange (ETDEWEB)

Padmanabhan, Nikhil; Schlegel, David J.; Finkbeiner, Douglas P.; Barentine, J.C.; Blanton, Michael R.; Brewington, Howard J.; Gunn, JamesE.; Harvanek, Michael; Hogg, David W.; Ivezic, Zeljko; Johnston, David; Kent, Stephen M.; Kleinman, S.J.; Knapp, Gillian R.; Krzesinski, Jurek; Long, Dan; Neilsen Jr., Eric H.; Nitta, Atsuko; Loomis, Craig; Lupton,Robert H.; Roweis, Sam; Snedden, Stephanie A.; Strauss, Michael A.; Tucker, Douglas L.

2007-09-30

We present an algorithm to photometrically calibrate widefield optical imaging surveys, that simultaneously solves for thecalibration parameters and relative stellar fluxes using overlappingobservations. The algorithm decouples the problem of "relative"calibrations from that of "absolute" calibrations; the absolutecalibration is reduced to determining a few numbers for the entiresurvey. We pay special attention to the spatial structure of thecalibration errors, allowing one to isolate particular error modes indownstream analyses. Applying this to the SloanDigital Sky Survey imagingdata, we achieve ~;1 percent relative calibration errors across 8500sq.deg/ in griz; the errors are ~;2 percent for the u band. These errorsare dominated by unmodelled atmospheric variations at Apache PointObservatory. These calibrations, dubbed ubercalibration, are now publicwith SDSS Data Release 6, and will be a part of subsequent SDSS datareleases.

Correlations among Galaxy Properties from the Sloan Digital Sky Survey

Science.gov (United States)

Li, Zhongmu; Mao, Caiyan

2013-07-01

Galaxies are complex systems with many properties. Correlations among galaxy properties can supply important clues for studying the formation and evolution of galaxies. Using principal component analysis and least-squares fitting, this paper investigates the correlations among galactic parameters involving more properties (color, morphology, stellar population, and absolute magnitude) than previous studies. We use a volume-limited sample (whole sample) of 75,423 galaxies that was selected from the Sloan Digital Sky Survey Data Release 2 and divided into two subsamples (blue and red samples) using a critical color of (g - r) = 0.70 mag. In addition to recovering some previous results, we also obtain some new results. First, all separators for dividing galaxies into two groups can be related via good parameter-first principal component (PC1) correlations. A critical PC1 that indicates whether or not stellar age (or the evolution of a stellar population over time) is important can be used to separate galaxies. This suggests that a statistical parameter, PC1, is helpful in understanding the physical separators of galaxies. In addition, stellar age is shown to be unimportant for red galaxies, while both stellar age and mass are dominating parameters of blue galaxies. This suggests that the various numbers of dominating parameters of galaxies may result from the use of different samples. Finally, some parameters are shown to be correlated, and quantitative fits for a few correlations are obtained, e.g., log(t) = 8.57 + 1.65 (g - r) for the age (log t) and color (g - r) of blue galaxies and log (M *) = 4.31 - 0.30 M r for the stellar mass (log M *) and absolute magnitude (M r) of red galaxies. The median relationships between various parameter pairs are also presented for comparison.

The Second Data Release of the Sloan Digital Sky Survey

CERN Document Server

Abazajian, Kevork; ̈ueros, Marcel A. Ag; Allam, Sahar S.; Anderson, KurtS. J.; Anderson, Scott F.; Annis, James; Bahcall, Neta A.; Baldry, Ivan K.; StevenBastian; Berlind, Andreas; Bernardi, Mariangela; Blanton, Michael R.; BochanskiJr., John J.; Boroski, William N.; Briggs, John W.; Brinkmann, J.; Brunner, Robert J.; ́ari, Tam ́asBudav; Carey, Larry N.; Carliles, Samuel; Castander, Francisco J.; Connolly, A. J.; Csabai, Istvan; Doi, Mamoru; Dong, Feng; Eisenstein, Daniel J.; Evans, Michael L.; Fan, Xiaohui; Finkbeiner, Douglas P.; Friedman, Scott D.; Frieman, Joshua A.; Fukugita, Masataka; Gal, RoyR.; Gillespie, Bruce; Glazebrook, Karl; Gray, Jim; Grebel, Eva K.; Gunn, James E.; Gurbani, Vijay K.; Hall, Patrick B.; Hamabe, Masaru; Harris, Frederick H.; C.Harris, Hugh; Harvanek, Michael; Heckman, Timothy M.; Hendry, John S.; Hennessy, Gregory S.; Hindsley, Robert B.; Hogan, Craig J.; Hogg, David W.; Holmgren, Donald J.; Ichikawa, Shin-ichi; Ichikawa, Takashi; Ivezic, Zeljko; Jester, Sebastian; Johnston, David E.; Jorgensen, AndersM.; Kent, Stephen M.; Kleinman, S. J.; Knapp, G. R.; Kniazev, Alexei Yu.; Kron, Richard G.; Krzesinski, Jurek; Kunszt, Peter Z.; Kuropatkin, Nickolai; Q.Lamb, Donald; Lampeitl, Hubert; Lee, Brian C.; Leger, R. French; Li, Nolan; Lin, Huan; Loh, Yeong-Shang; Long, Daniel C.; Loveday, Jon; Lupton, Robert H.; Malik, Tanu; BruceMargon; Matsubara, Takahiko; McGehee, Peregrine M.; McKay, Timothy A.; AveryMeiksin; Munn, Jeffrey A.; Nakajima, Reiko; Nash, Thomas; Neilsen, Eric H. Jr.; JoNewberg, Heidi; Newman, Peter R.; Nichol, Robert C.; Nicinski, Tom; Nieto-Santisteban, Maria; Nitta, Atsuko; Okamura, Sadanori; O'Mullane, William; Ostriker, Jeremiah P.; Owen, Russell; Padmanabhan, Nikhil; Peoples, John; Pier, Jeffrey R.; Pope, Adrian C.; Quinn, Thomas R.; Richards, Gordon T.; Richmond, Michael W.; Rix, Hans-Walter; Rockosi, Constance M.; Schlegel, David J.; Schneider, Donald P.; Scranton, Ryan; Sekiguchi, Maki; Seljak, Uros; Sergey, Gary; Sesar, Branimir; Sheldon, Erin; Shimasaku, Kazu; Siegmund, Walter A.; Silvestri, Nicole M.; Smith, J. Allyn; ́c, Vernesa Smolči; Snedden, Stephanie A.; AlbertStebbins; Stoughton, Chris; Strauss, Michael A.; SubbaRao, Mark; Szalay, Alexander S.; Szapudi, Istv ́an; Szkody, Paula; Szokoly, Gyula P.; Tegmark, Max; Teodoro, Luis; Thakar, AniruddhaR.; Tremonti, Christy; Tucker, Douglas L.; Uomoto, Alan; Vanden Berk, Daniel E.; Vandenberg, Jan; Vogeley, Michael S.; Voges, Wolfgang; Vogt, Nicole P.; M.Walkowicz, Lucianne; Wang, Shu-i; Weinberg, David H.; West, Andrew A.; White, Simon D.M.; Wilhite, BrianC.; Xu, Yongzhong; Yanny, Brian; Yasuda, Naoki; Yip, Ching-Wa; Yocum, D. R.; York, Donald G.; Zehavi, Idit; Zibetti, Stefano; Zucker, Daniel B.

2004-01-01

The Sloan Digital Sky Survey has validated and made publicly available its Second Data Release. This data release consists of 3324 square degrees of five-band (u g r i z) imaging data with photometry for over 88 million unique objects, 367,360 spectra of galaxies, quasars, stars and calibrating blank sky patches selected over 2627 degrees of this area, and tables of measured parameters from these data. The imaging data reach a depth of r ~ 22.2 (95% completeness limit for point sources) and are photometrically and astrometrically calibrated to 2% rms and 100 milli-arcsec rms per coordinate, respectively. The imaging data have all been processed through a new version of the SDSS imaging pipeline, in which the most important improvement since the last data release is fixing an error in the model fits to each object. The result is that model magnitudes are now a good proxy for point spread function (PSF) magnitudes for point sources, and Petrosian magnitudes for extended sources. The spectroscopy extends from 38...

Ensemble Properties of Comets in the Sloan Digital Sky Survey

Energy Technology Data Exchange (ETDEWEB)

Solontoi, Michael; /Adler Planetarium, Chicago; Ivezic, Zeljko; /Washington U., Seattle, Astron. Dept.; Juric, Mario; /Harvard Coll. Observ.; Becker, Andrew C.; /Washington U., Seattle, Astron. Dept.; Jones, Lynne; /Washington U., Seattle, Astron. Dept.; West, Andrew A.; /Boston U.; Kent, Steve; /Fermilab; Lupton, Robert H.; /Princeton U. Observ.; Claire, Mark; /Washington U., Seattle, Astron. Dept.; Knapp, Gillian R.; /Princeton U. Observ.; Quinn, Tom; /Washington U., Seattle, Astron. Dept. /Princeton U. Observ.

2012-02-01

We present the ensemble properties of 31 comets (27 resolved and 4 unresolved) observed by the Sloan Digital Sky Survey (SDSS). This sample of comets represents about 1 comet per 10 million SDSS photometric objects. Five-band (u, g, r, i, z) photometry is used to determine the comets colors, sizes, surface brightness profiles, and rates of dust production in terms of the Afp formalism. We find that the cumulative luminosity function for the Jupiter Family Comets in our sample is well fit by a power law of the form N(

IMPROVED BACKGROUND SUBTRACTION FOR THE SLOAN DIGITAL SKY SURVEY IMAGES

International Nuclear Information System (INIS)

Blanton, Michael R.; Kazin, Eyal; Muna, Demitri; Weaver, Benjamin A.; Price-Whelan, Adrian

2011-01-01

We describe a procedure for background subtracting Sloan Digital Sky Survey (SDSS) imaging that improves the resulting detection and photometry of large galaxies on the sky. Within each SDSS drift scan run, we mask out detected sources and then fit a smooth function to the variation of the sky background. This procedure has been applied to all SDSS-III Data Release 8 images, and the results are available as part of that data set. We have tested the effect of our background subtraction on the photometry of large galaxies by inserting fake galaxies into the raw pixels, reanalyzing the data, and measuring them after background subtraction. Our technique results in no size-dependent bias in galaxy fluxes up to half-light radii r 50 ∼ 100 arcsec; in contrast, for galaxies of that size the standard SDSS photometric catalog underestimates fluxes by about 1.5 mag. Our results represent a substantial improvement over the standard SDSS catalog results and should form the basis of any analysis of nearby galaxies using the SDSS imaging data.

COSMOLOGICAL CONSTRAINTS FROM THE SLOAN DIGITAL SKY SURVEY MaxBCG CLUSTER CATALOG

International Nuclear Information System (INIS)

Rozo, Eduardo; Weinberg, David H.; Wechsler, Risa H.; Rykoff, Eli S.; Annis, James T.; Frieman, Joshua A.; Becker, Matthew R.; Evrard, August E.; Hao Jiangang; McKay, Timothy A.; Hansen, Sarah M.; Johnston, David E.; Koester, Benjamin P.; Sheldon, Erin S.

2010-01-01

We use the abundance and weak-lensing mass measurements of the Sloan Digital Sky Survey maxBCG cluster catalog to simultaneously constrain cosmology and the richness-mass relation of the clusters. Assuming a flat ΛCDM cosmology, we find σ 8 (Ω m /0.25) 0.41 = 0.832 ± 0.033 after marginalization over all systematics. In common with previous studies, our error budget is dominated by systematic uncertainties, the primary two being the absolute mass scale of the weak-lensing masses of the maxBCG clusters, and uncertainty in the scatter of the richness-mass relation. Our constraints are fully consistent with the WMAP five-year data, and in a joint analysis we find σ 8 = 0.807 ± 0.020 and Ω m = 0.265 ± 0.016, an improvement of nearly a factor of 2 relative to WMAP5 alone. Our results are also in excellent agreement with and comparable in precision to the latest cosmological constraints from X-ray cluster abundances. The remarkable consistency among these results demonstrates that cluster abundance constraints are not only tight but also robust, and highlight the power of optically selected cluster samples to produce precision constraints on cosmological parameters.

A Flipped First-Year Digital Circuits Course for Engineering and Technology Students

Science.gov (United States)

Yelamarthi, Kumar; Drake, Eron

2015-01-01

This paper describes a flipped and improved first-year digital circuits (DC) course that incorporates several active learning strategies. With the primary objective of increasing student interest and learning, an integrated instructional design framework is proposed to provide first-year engineering and technology students with practical knowledge…

Genus Topology of Structure in the Sloan Digital Sky Survey: Model Testing

Science.gov (United States)

Gott, J. Richard, III; Hambrick, D. Clay; Vogeley, Michael S.; Kim, Juhan; Park, Changbom; Choi, Yun-Young; Cen, Renyue; Ostriker, Jeremiah P.; Nagamine, Kentaro

2008-03-01

We measure the three-dimensional topology of large-scale structure in the Sloan Digital Sky Survey (SDSS). This allows the genus statistic to be measured with unprecedented statistical accuracy. The sample size is now sufficiently large to allow the topology to be an important tool for testing galaxy formation models. For comparison, we make mock SDSS samples using several state-of-the-art N-body simulations: the Millennium run of Springel et al. (10 billion particles), the Kim & Park CDM models (1.1 billion particles), and the Cen & Ostriker hydrodynamic code models (8.6 billion cell hydro mesh). Each of these simulations uses a different method for modeling galaxy formation. The SDSS data show a genus curve that is broadly characteristic of that produced by Gaussian random-phase initial conditions. Thus, the data strongly support the standard model of inflation where Gaussian random-phase initial conditions are produced by random quantum fluctuations in the early universe. But on top of this general shape there are measurable differences produced by nonlinear gravitational effects and biasing connected with galaxy formation. The N-body simulations have been tuned to reproduce the power spectrum and multiplicity function but not topology, so topology is an acid test for these models. The data show a "meatball" shift (only partly due to the Sloan Great Wall of galaxies) that differs at the 2.5 σ level from the results of the Millenium run and the Kim & Park dark halo models, even including the effects of cosmic variance.

Narrow absorption lines with two observations from the Sloan Digital Sky Survey

Science.gov (United States)

Chen, Zhi-Fu; Gu, Qiu-Sheng; Chen, Yan-Mei; Cao, Yue

2015-07-01

We assemble 3524 quasars from the Sloan Digital Sky Survey (SDSS) with repeated observations to search for variations of the narrow C IV λ λ 1548,1551 and Mg II λ λ 2796,2803 absorption doublets in spectral regions shortward of 7000 Å in the observed frame, which corresponds to time-scales of about 150-2643 d in the quasar rest frame. In these quasar spectra, we detect 3580 C IV absorption systems with zabs = 1.5188-3.5212 and 1809 Mg II absorption systems with zabs = 0.3948-1.7167. In term of the absorber velocity (β) distribution in the quasar rest frame, we find a substantial number of C IV absorbers with β Hacker et al. However, in our Mg II absorption sample, we find that neither shows variable absorption with confident levels of >4σ for λ2796 lines and >3σ for λ2803 lines.

INNOCENT BYSTANDERS: CARBON STARS FROM THE SLOAN DIGITAL SKY SURVEY

International Nuclear Information System (INIS)

Green, Paul

2013-01-01

Among stars showing carbon molecular bands (C stars), the main-sequence dwarfs, likely in post-mass transfer binaries, are numerically dominant in the Galaxy. Via spectroscopic selection from the Sloan Digital Sky Survey, we retrieve 1220 high galactic latitude C stars, ∼5 times more than previously known, including a wider variety than past techniques such as color or grism selection have netted, and additionally yielding 167 DQ white dwarfs. Of the C stars with proper motion measurements, we identify 69% clearly as dwarfs (dCs), while ∼7% are giants. The dCs likely span absolute magnitudes M i from ∼6.5 to 10.5. 'G-type' dC stars with weak CN and relatively blue colors are probably the most massive dCs still cool enough to show C 2 bands. We report Balmer emission in 22 dCs, none of which are G-types. We find 8 new DA/dC stars in composite spectrum binaries, quadrupling the total sample of these 'smoking guns' for AGB binary mass transfer. Eleven very red C stars with strong red CN bands appear to be 'N'-type AGB stars at large Galactocentric distances, one likely a new discovery in the dIrr galaxy Leo A. Two such stars within 30' of each other may trace a previously unidentified dwarf galaxy or tidal stream at ∼40 kpc. We explore the multiwavelength properties of the sample and report the first X-ray detection of a dC star, which shows strong Balmer emission. Our own spectroscopic survey additionally provides the dC surface density from a complete sample of dwarfs limited by magnitude, color, and proper motion.

Innocent Bystanders: Carbon Stars from the Sloan Digital Sky Survey

Science.gov (United States)

Green, Paul

2013-03-01

Among stars showing carbon molecular bands (C stars), the main-sequence dwarfs, likely in post-mass transfer binaries, are numerically dominant in the Galaxy. Via spectroscopic selection from the Sloan Digital Sky Survey, we retrieve 1220 high galactic latitude C stars, ~5 times more than previously known, including a wider variety than past techniques such as color or grism selection have netted, and additionally yielding 167 DQ white dwarfs. Of the C stars with proper motion measurements, we identify 69% clearly as dwarfs (dCs), while ~7% are giants. The dCs likely span absolute magnitudes Mi from ~6.5 to 10.5. "G-type" dC stars with weak CN and relatively blue colors are probably the most massive dCs still cool enough to show C2 bands. We report Balmer emission in 22 dCs, none of which are G-types. We find 8 new DA/dC stars in composite spectrum binaries, quadrupling the total sample of these "smoking guns" for AGB binary mass transfer. Eleven very red C stars with strong red CN bands appear to be "N"-type AGB stars at large Galactocentric distances, one likely a new discovery in the dIrr galaxy Leo A. Two such stars within 30' of each other may trace a previously unidentified dwarf galaxy or tidal stream at ~40 kpc. We explore the multiwavelength properties of the sample and report the first X-ray detection of a dC star, which shows strong Balmer emission. Our own spectroscopic survey additionally provides the dC surface density from a complete sample of dwarfs limited by magnitude, color, and proper motion.

C IV BROAD ABSORPTION LINE ACCELERATION IN SLOAN DIGITAL SKY SURVEY QUASARS

Energy Technology Data Exchange (ETDEWEB)

Grier, C. J.; Brandt, W. N.; Trump, J. R.; Schneider, D. P.; Sun, M.; Beatty, T. G. [Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Hall, P. B. [Department of Physics and Astronomy, York University, Toronto, ON M3J 1P3 (Canada); Filiz Ak, N. [Faculty of Sciences, Department of Astronomy and Space Sciences, Erciyes University, 38039 Kayseri (Turkey); Anderson, S. F. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Green, Paul J. [Harvard Smithsonian Center for Astrophysics, 60 Garden St, Cambridge, MA 02138 (United States); Vivek, M.; Brownstein, Joel R. [Department of Physics and Astronomy, University of Utah, 115 S. 1400 E., Salt Lake City, UT 84112 (United States); Roman-Lopes, Alexandre, E-mail: grier@psu.edu [Departamento de Fisica, Facultad de Ciencias, Universidad de La Serena, Cisternas 1200, La Serena (Chile)

2016-06-20

We present results from the largest systematic investigation of broad absorption line (BAL) acceleration to date. We use spectra of 140 quasars from three Sloan Digital Sky Survey programs to search for global velocity offsets in BALs over timescales of ≈2.5–5.5 years in the quasar rest frame. We carefully select acceleration candidates by requiring monolithic velocity shifts over the entire BAL trough, avoiding BALs with velocity shifts that might be caused by profile variability. The C iv BALs of two quasars show velocity shifts consistent with the expected signatures of BAL acceleration, and the BAL of one quasar shows a velocity-shift signature of deceleration. In our two acceleration candidates, we see evidence that the magnitude of the acceleration is not constant over time; the magnitudes of the change in acceleration for both acceleration candidates are difficult to produce with a standard disk-wind model or via geometric projection effects. We measure upper limits to acceleration and deceleration for 76 additional BAL troughs and find that the majority of BALs are stable to within about 3% of their mean velocities. The lack of widespread acceleration/deceleration could indicate that the gas producing most BALs is located at large radii from the central black hole and/or is not currently strongly interacting with ambient material within the host galaxy along our line of sight.

THE SLOAN DIGITAL SKY SURVEY REVERBERATION MAPPING PROJECT: TECHNICAL OVERVIEW

Energy Technology Data Exchange (ETDEWEB)

Shen, Yue [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Brandt, W. N. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Dawson, Kyle S. [Department of Physics and Astronomy, University of Utah, 115 South 1400 East, Salt Lake City, UT 84112 (United States); Hall, Patrick B. [Department of Physics and Astronomy, York University, Toronto, ON M3J 1P3 (Canada); McGreer, Ian D.; Fan, Xiaohui [Steward Observatory, The University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721-0065 (United States); Anderson, Scott F. [Astronomy Department, University of Washington, Box 351580, Seattle, WA 98195 (United States); Chen, Yuguang [Department of Astronomy, School of Physics, Peking University, Beijing 100871 (China); Denney, Kelly D. [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Eftekharzadeh, Sarah [Department of Physics and Astronomy, University of Wyoming, 1000 East University Avenue, Laramie, WY 82071 (United States); Gao, Yang [Department of Engineering Physics and Center for Astrophysics, Tsinghua University, Beijing 100084 (China); Green, Paul J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Greene, Jenny E. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Ho, Luis C. [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China); Horne, Keith [SUPA Physics/Astronomy, University of St. Andrews, St. Andrews KY16 9SS (United Kingdom); Jiang, Linhua [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287-1504 (United States); Kelly, Brandon C. [Department of Physics, Broida Hall, University of California, Santa Barbara, CA 93107 (United States); and others

2015-01-01

The Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project is a dedicated multi-object RM experiment that has spectroscopically monitored a sample of 849 broad-line quasars in a single 7 deg{sup 2} field with the SDSS-III Baryon Oscillation Spectroscopic Survey spectrograph. The RM quasar sample is flux-limited to i {sub psf} = 21.7 mag, and covers a redshift range of 0.1 < z < 4.5 without any other cuts on quasar properties. Optical spectroscopy was performed during 2014 January-July dark/gray time, with an average cadence of ∼4 days, totaling more than 30 epochs. Supporting photometric monitoring in the g and i bands was conducted at multiple facilities including the Canada-France-Hawaii Telescope (CFHT) and the Steward Observatory Bok telescope in 2014, with a cadence of ∼2 days and covering all lunar phases. The RM field (R.A., decl. = 14:14:49.00, +53:05:00.0) lies within the CFHT-LS W3 field, and coincides with the Pan-STARRS 1 (PS1) Medium Deep Field MD07, with three prior years of multi-band PS1 light curves. The SDSS-RM six month baseline program aims to detect time lags between the quasar continuum and broad line region (BLR) variability on timescales of up to several months (in the observed frame) for ∼10% of the sample, and to anchor the time baseline for continued monitoring in the future to detect lags on longer timescales and at higher redshift. SDSS-RM is the first major program to systematically explore the potential of RM for broad-line quasars at z > 0.3, and will investigate the prospects of RM with all major broad lines covered in optical spectroscopy. SDSS-RM will provide guidance on future multi-object RM campaigns on larger scales, and is aiming to deliver more than tens of BLR lag detections for a homogeneous sample of quasars. We describe the motivation, design, and implementation of this program, and outline the science impact expected from the resulting data for RM and general quasar science.

THE SLOAN DIGITAL SKY SURVEY REVERBERATION MAPPING PROJECT: TECHNICAL OVERVIEW

International Nuclear Information System (INIS)

Shen, Yue; Brandt, W. N.; Dawson, Kyle S.; Hall, Patrick B.; McGreer, Ian D.; Fan, Xiaohui; Anderson, Scott F.; Chen, Yuguang; Denney, Kelly D.; Eftekharzadeh, Sarah; Gao, Yang; Green, Paul J.; Greene, Jenny E.; Ho, Luis C.; Horne, Keith; Jiang, Linhua; Kelly, Brandon C.

2015-01-01

The Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project is a dedicated multi-object RM experiment that has spectroscopically monitored a sample of 849 broad-line quasars in a single 7 deg 2 field with the SDSS-III Baryon Oscillation Spectroscopic Survey spectrograph. The RM quasar sample is flux-limited to i psf = 21.7 mag, and covers a redshift range of 0.1 < z < 4.5 without any other cuts on quasar properties. Optical spectroscopy was performed during 2014 January-July dark/gray time, with an average cadence of ∼4 days, totaling more than 30 epochs. Supporting photometric monitoring in the g and i bands was conducted at multiple facilities including the Canada-France-Hawaii Telescope (CFHT) and the Steward Observatory Bok telescope in 2014, with a cadence of ∼2 days and covering all lunar phases. The RM field (R.A., decl. = 14:14:49.00, +53:05:00.0) lies within the CFHT-LS W3 field, and coincides with the Pan-STARRS 1 (PS1) Medium Deep Field MD07, with three prior years of multi-band PS1 light curves. The SDSS-RM six month baseline program aims to detect time lags between the quasar continuum and broad line region (BLR) variability on timescales of up to several months (in the observed frame) for ∼10% of the sample, and to anchor the time baseline for continued monitoring in the future to detect lags on longer timescales and at higher redshift. SDSS-RM is the first major program to systematically explore the potential of RM for broad-line quasars at z > 0.3, and will investigate the prospects of RM with all major broad lines covered in optical spectroscopy. SDSS-RM will provide guidance on future multi-object RM campaigns on larger scales, and is aiming to deliver more than tens of BLR lag detections for a homogeneous sample of quasars. We describe the motivation, design, and implementation of this program, and outline the science impact expected from the resulting data for RM and general quasar science

Discovery of three strongly lensed quasars in the Sloan Digital Sky Survey

Science.gov (United States)

Williams, P. R.; Agnello, A.; Treu, T.; Abramson, L. E.; Anguita, T.; Apostolovski, Y.; Chen, G. C.-F.; Fassnacht, C. D.; Hsueh, J. W.; Lemaux, B. C.; Motta, V.; Oldham, L.; Rojas, K.; Rusu, C. E.; Shajib, A. J.; Wang, X.

2018-06-01

We present the discovery of three quasar lenses in the Sloan Digital Sky Survey, selected using two novel photometry-based selection techniques. The J0941+0518 system, with two point sources separated by 5.46 arcsec on either side of a galaxy, has source and lens redshifts 1.54 and 0.343. Images of J2257+2349 show two point sources separated by 1.67 arcsec on either side of an E/S0 galaxy. The extracted spectra show two images of the same quasar at zs = 2.10. SDSS J1640+1045 has two quasar spectra at zs = 1.70 and fits to the SDSS and Pan-STARRS images confirm the presence of a galaxy between the two point sources. We observed 56 photometrically selected lens candidates in this follow-up campaign, confirming three new lenses, re-discovering one known lens, and ruling out 36 candidates, with 16 still inconclusive. This initial campaign demonstrates the power of purely photometric selection techniques in finding lensed quasars.

A high-resolution atlas of composite Sloan Digital Sky Survey galaxy spectra

Science.gov (United States)

Dobos, László; Csabai, István.; Yip, Ching-Wa; Budavári, Tamás.; Wild, Vivienne; Szalay, Alexander S.

2012-02-01

In this work we present an atlas of composite spectra of galaxies based on the data of the Sloan Digital Sky Survey Data Release 7 (SDSS DR7). Galaxies are classified by colour, nuclear activity and star formation activity to calculate average spectra of high signal-to-noise ratio (S/N) and resolution (? at Δλ= 1 Å), using an algorithm that is robust against outliers. Besides composite spectra, we also compute the first five principal components of the distributions in each galaxy class to characterize the nature of variations of individual spectra around the averages. The continua of the composite spectra are fitted with BC03 stellar population synthesis models to extend the wavelength coverage beyond the coverage of the SDSS spectrographs. Common derived parameters of the composites are also calculated: integrated colours in the most popular filter systems, line-strength measurements and continuum absorption indices (including Lick indices). These derived parameters are compared with the distributions of parameters of individual galaxies, and it is shown on many examples that the composites of the atlas cover much of the parameter space spanned by SDSS galaxies. By co-adding thousands of spectra, a total integration time of several months can be reached, which results in extremely low noise composites. The variations in redshift not only allow for extending the spectral coverage bluewards to the original wavelength limit of the SDSS spectrographs, but also make higher spectral resolution achievable. The composite spectrum atlas is available online at .

The Digitally Disadvantaged: Access to Digital Communication Technologies among First Year Students at a Rural South African University

Science.gov (United States)

Oyedemi, Toks; Mogano, Saki

2018-01-01

Considering the importance of digital skills in university education, this article reports on a study which examined access to technology among first year students at a rural South African university. The study focused on the digital readiness of students prior to their admission to the university, since many universities provide access to…

INNOCENT BYSTANDERS: CARBON STARS FROM THE SLOAN DIGITAL SKY SURVEY

Energy Technology Data Exchange (ETDEWEB)

Green, Paul [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)

2013-03-01

Among stars showing carbon molecular bands (C stars), the main-sequence dwarfs, likely in post-mass transfer binaries, are numerically dominant in the Galaxy. Via spectroscopic selection from the Sloan Digital Sky Survey, we retrieve 1220 high galactic latitude C stars, {approx}5 times more than previously known, including a wider variety than past techniques such as color or grism selection have netted, and additionally yielding 167 DQ white dwarfs. Of the C stars with proper motion measurements, we identify 69% clearly as dwarfs (dCs), while {approx}7% are giants. The dCs likely span absolute magnitudes M{sub i} from {approx}6.5 to 10.5. 'G-type' dC stars with weak CN and relatively blue colors are probably the most massive dCs still cool enough to show C{sub 2} bands. We report Balmer emission in 22 dCs, none of which are G-types. We find 8 new DA/dC stars in composite spectrum binaries, quadrupling the total sample of these 'smoking guns' for AGB binary mass transfer. Eleven very red C stars with strong red CN bands appear to be 'N'-type AGB stars at large Galactocentric distances, one likely a new discovery in the dIrr galaxy Leo A. Two such stars within 30' of each other may trace a previously unidentified dwarf galaxy or tidal stream at {approx}40 kpc. We explore the multiwavelength properties of the sample and report the first X-ray detection of a dC star, which shows strong Balmer emission. Our own spectroscopic survey additionally provides the dC surface density from a complete sample of dwarfs limited by magnitude, color, and proper motion.

The sloan digital sky Survey-II supernova survey: search algorithm and follow-up observations

Energy Technology Data Exchange (ETDEWEB)

Sako, Masao [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Bassett, Bruce [Department of Mathematics and Applied Mathematics, University of Cape Town, Rondebosch 7701 (South Africa); Becker, Andrew; Hogan, Craig J. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Cinabro, David [Department of Physics, Wayne State University, Detroit, MI 48202 (United States); DeJongh, Fritz; Frieman, Joshua A.; Marriner, John; Miknaitis, Gajus [Center for Particle Astrophysics, Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States); Depoy, D. L.; Prieto, Jose Luis [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210-1173 (United States); Dilday, Ben; Kessler, Richard [Kavli Institute for Cosmological Physics, The University of Chicago, 5640 South Ellis Avenue Chicago, IL 60637 (United States); Doi, Mamoru [Institute of Astronomy, Graduate School of Science, University of Tokyo 2-21-1, Osawa, Mitaka, Tokyo 181-0015 (Japan); Garnavich, Peter M. [University of Notre Dame, 225 Nieuwland Science, Notre Dame, IN 46556-5670 (United States); Holtzman, Jon [Department of Astronomy, MSC 4500, New Mexico State University, P.O. Box 30001, Las Cruces, NM 88003 (United States); Jha, Saurabh [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, P.O. Box 20450, MS29, Stanford, CA 94309 (United States); Konishi, Kohki [Institute for Cosmic Ray Research, University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa, Chiba, 277-8582 (Japan); Lampeitl, Hubert [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Nichol, Robert C. [Institute of Cosmology and Gravitation, Mercantile House, Hampshire Terrace, University of Portsmouth, Portsmouth PO1 2EG (United Kingdom); and others

2008-01-01

The Sloan Digital Sky Survey-II Supernova Survey has identified a large number of new transient sources in a 300 deg{sup 2} region along the celestial equator during its first two seasons of a three-season campaign. Multi-band (ugriz) light curves were measured for most of the sources, which include solar system objects, galactic variable stars, active galactic nuclei, supernovae (SNe), and other astronomical transients. The imaging survey is augmented by an extensive spectroscopic follow-up program to identify SNe, measure their redshifts, and study the physical conditions of the explosions and their environment through spectroscopic diagnostics. During the survey, light curves are rapidly evaluated to provide an initial photometric type of the SNe, and a selected sample of sources are targeted for spectroscopic observations. In the first two seasons, 476 sources were selected for spectroscopic observations, of which 403 were identified as SNe. For the type Ia SNe, the main driver for the survey, our photometric typing and targeting efficiency is 90%. Only 6% of the photometric SN Ia candidates were spectroscopically classified as non-SN Ia instead, and the remaining 4% resulted in low signal-to-noise, unclassified spectra. This paper describes the search algorithm and the software, and the real-time processing of the SDSS imaging data. We also present the details of the supernova candidate selection procedures and strategies for follow-up spectroscopic and imaging observations of the discovered sources.

The Sloan Digital Sky Survey-II Supernova Survey:Search Algorithm and Follow-up Observations

Energy Technology Data Exchange (ETDEWEB)

Sako, Masao; /Pennsylvania U. /KIPAC, Menlo Park; Bassett, Bruce; /Cape Town U. /South African Astron. Observ.; Becker, Andrew; /Washington U., Seattle, Astron. Dept.; Cinabro, David; /Wayne State U.; DeJongh, Don Frederic; /Fermilab; Depoy, D.L.; /Ohio State U.; Doi, Mamoru; /Tokyo U.; Garnavich, Peter M.; /Notre Dame U.; Craig, Hogan, J.; /Washington U., Seattle, Astron. Dept.; Holtzman, Jon; /New Mexico State U.; Jha, Saurabh; /Stanford U., Phys. Dept.; Konishi, Kohki; /Tokyo U.; Lampeitl, Hubert; /Baltimore, Space; Marriner, John; /Fermilab; Miknaitis, Gajus; /Fermilab; Nichol, Robert C.; /Portsmouth U.; Prieto, Jose Luis; /Ohio State U.; Richmond, Michael W.; /Rochester Inst.; Schneider, Donald P.; /Penn State U., Astron. Astrophys.; Smith, Mathew; /Portsmouth U.; SubbaRao, Mark; /Chicago U. /Tokyo U. /Tokyo U. /South African Astron. Observ. /Tokyo

2007-09-14

The Sloan Digital Sky Survey-II Supernova Survey has identified a large number of new transient sources in a 300 deg2 region along the celestial equator during its first two seasons of a three-season campaign. Multi-band (ugriz) light curves were measured for most of the sources, which include solar system objects, Galactic variable stars, active galactic nuclei, supernovae (SNe), and other astronomical transients. The imaging survey is augmented by an extensive spectroscopic follow-up program to identify SNe, measure their redshifts, and study the physical conditions of the explosions and their environment through spectroscopic diagnostics. During the survey, light curves are rapidly evaluated to provide an initial photometric type of the SNe, and a selected sample of sources are targeted for spectroscopic observations. In the first two seasons, 476 sources were selected for spectroscopic observations, of which 403 were identified as SNe. For the Type Ia SNe, the main driver for the Survey, our photometric typing and targeting efficiency is 90%. Only 6% of the photometric SN Ia candidates were spectroscopically classified as non-SN Ia instead, and the remaining 4% resulted in low signal-to-noise, unclassified spectra. This paper describes the search algorithm and the software, and the real-time processing of the SDSS imaging data. We also present the details of the supernova candidate selection procedures and strategies for follow-up spectroscopic and imaging observations of the discovered sources.

The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the Extended Baryon Oscillation Spectroscopic Survey and from the Second Phase of the Apache Point Observatory Galactic Evolution Experiment

Science.gov (United States)

Abolfathi, Bela; Aguado, D. S.; Aguilar, Gabriela; Allende Prieto, Carlos; Almeida, Andres; Tasnim Ananna, Tonima; Anders, Friedrich; Anderson, Scott F.; Andrews, Brett H.; Anguiano, Borja; Aragón-Salamanca, Alfonso; Argudo-Fernández, Maria; Armengaud, Eric; Ata, Metin; Aubourg, Eric; Avila-Reese, Vladimir; Badenes, Carles; Bailey, Stephen; Balland, Christophe; Barger, Kathleen A.; Barrera-Ballesteros, Jorge; Bartosz, Curtis; Bastien, Fabienne; Bates, Dominic; Baumgarten, Falk; Bautista, Julian; Beaton, Rachael; Beers, Timothy C.; Belfiore, Francesco; Bender, Chad F.; Bernardi, Mariangela; Bershady, Matthew A.; Beutler, Florian; Bird, Jonathan C.; Bizyaev, Dmitry; Blanc, Guillermo A.; Blanton, Michael R.; Blomqvist, Michael; Bolton, Adam S.; Boquien, Médéric; Borissova, Jura; Bovy, Jo; Andres Bradna Diaz, Christian; Nielsen Brandt, William; Brinkmann, Jonathan; Brownstein, Joel R.; Bundy, Kevin; Burgasser, Adam J.; Burtin, Etienne; Busca, Nicolás G.; Cañas, Caleb I.; Cano-Díaz, Mariana; Cappellari, Michele; Carrera, Ricardo; Casey, Andrew R.; Cervantes Sodi, Bernardo; Chen, Yanping; Cherinka, Brian; Chiappini, Cristina; Doohyun Choi, Peter; Chojnowski, Drew; Chuang, Chia-Hsun; Chung, Haeun; Clerc, Nicolas; Cohen, Roger E.; Comerford, Julia M.; Comparat, Johan; Correa do Nascimento, Janaina; da Costa, Luiz; Cousinou, Marie-Claude; Covey, Kevin; Crane, Jeffrey D.; Cruz-Gonzalez, Irene; Cunha, Katia; da Silva Ilha, Gabriele; Damke, Guillermo J.; Darling, Jeremy; Davidson, James W., Jr.; Dawson, Kyle; de Icaza Lizaola, Miguel Angel C.; de la Macorra, Axel; de la Torre, Sylvain; De Lee, Nathan; de Sainte Agathe, Victoria; Deconto Machado, Alice; Dell’Agli, Flavia; Delubac, Timothée; Diamond-Stanic, Aleksandar M.; Donor, John; José Downes, Juan; Drory, Niv; du Mas des Bourboux, Hélion; Duckworth, Christopher J.; Dwelly, Tom; Dyer, Jamie; Ebelke, Garrett; Davis Eigenbrot, Arthur; Eisenstein, Daniel J.; Elsworth, Yvonne P.; Emsellem, Eric; Eracleous, Michael; Erfanianfar, Ghazaleh; Escoffier, Stephanie; Fan, Xiaohui; Fernández Alvar, Emma; Fernandez-Trincado, J. G.; Cirolini, Rafael Fernando; Feuillet, Diane; Finoguenov, Alexis; Fleming, Scott W.; Font-Ribera, Andreu; Freischlad, Gordon; Frinchaboy, Peter; Fu, Hai; Gómez Maqueo Chew, Yilen; Galbany, Lluís; García Pérez, Ana E.; Garcia-Dias, R.; García-Hernández, D. A.; Garma Oehmichen, Luis Alberto; Gaulme, Patrick; Gelfand, Joseph; Gil-Marín, Héctor; Gillespie, Bruce A.; Goddard, Daniel; González Hernández, Jonay I.; Gonzalez-Perez, Violeta; Grabowski, Kathleen; Green, Paul J.; Grier, Catherine J.; Gueguen, Alain; Guo, Hong; Guy, Julien; Hagen, Alex; Hall, Patrick; Harding, Paul; Hasselquist, Sten; Hawley, Suzanne; Hayes, Christian R.; Hearty, Fred; Hekker, Saskia; Hernandez, Jesus; Hernandez Toledo, Hector; Hogg, David W.; Holley-Bockelmann, Kelly; Holtzman, Jon A.; Hou, Jiamin; Hsieh, Bau-Ching; Hunt, Jason A. S.; Hutchinson, Timothy A.; Hwang, Ho Seong; Jimenez Angel, Camilo Eduardo; Johnson, Jennifer A.; Jones, Amy; Jönsson, Henrik; Jullo, Eric; Sakil Khan, Fahim; Kinemuchi, Karen; Kirkby, David; Kirkpatrick, Charles C., IV; Kitaura, Francisco-Shu; Knapp, Gillian R.; Kneib, Jean-Paul; Kollmeier, Juna A.; Lacerna, Ivan; Lane, Richard R.; Lang, Dustin; Law, David R.; Le Goff, Jean-Marc; Lee, Young-Bae; Li, Hongyu; Li, Cheng; Lian, Jianhui; Liang, Yu; Lima, Marcos; Lin, Lihwai; Long, Dan; Lucatello, Sara; Lundgren, Britt; Mackereth, J. Ted; MacLeod, Chelsea L.; Mahadevan, Suvrath; Geimba Maia, Marcio Antonio; Majewski, Steven; Manchado, Arturo; Maraston, Claudia; Mariappan, Vivek; Marques-Chaves, Rui; Masseron, Thomas; Masters, Karen L.; McDermid, Richard M.; McGreer, Ian D.; Melendez, Matthew; Meneses-Goytia, Sofia; Merloni, Andrea; Merrifield, Michael R.; Meszaros, Szabolcs; Meza, Andres; Minchev, Ivan; Minniti, Dante; Mueller, Eva-Maria; Muller-Sanchez, Francisco; Muna, Demitri; Muñoz, Ricardo R.; Myers, Adam D.; Nair, Preethi; Nandra, Kirpal; Ness, Melissa; Newman, Jeffrey A.; Nichol, Robert C.; Nidever, David L.; Nitschelm, Christian; Noterdaeme, Pasquier; O’Connell, Julia; Oelkers, Ryan James; Oravetz, Audrey; Oravetz, Daniel; Aquino Ortíz, Erik; Osorio, Yeisson; Pace, Zach; Padilla, Nelson; Palanque-Delabrouille, Nathalie; Alonso Palicio, Pedro; Pan, Hsi-An; Pan, Kaike; Parikh, Taniya; Pâris, Isabelle; Park, Changbom; Peirani, Sebastien; Pellejero-Ibanez, Marcos; Penny, Samantha; Percival, Will J.; Perez-Fournon, Ismael; Petitjean, Patrick; Pieri, Matthew M.; Pinsonneault, Marc; Pisani, Alice; Prada, Francisco; Prakash, Abhishek; Queiroz, Anna Bárbara de Andrade; Raddick, M. Jordan; Raichoor, Anand; Barboza Rembold, Sandro; Richstein, Hannah; Riffel, Rogemar A.; Riffel, Rogério; Rix, Hans-Walter; Robin, Annie C.; Rodríguez Torres, Sergio; Román-Zúñiga, Carlos; Ross, Ashley J.; Rossi, Graziano; Ruan, John; Ruggeri, Rossana; Ruiz, Jose; Salvato, Mara; Sánchez, Ariel G.; Sánchez, Sebastián F.; Sanchez Almeida, Jorge; Sánchez-Gallego, José R.; Santana Rojas, Felipe Antonio; Santiago, Basílio Xavier; Schiavon, Ricardo P.; Schimoia, Jaderson S.; Schlafly, Edward; Schlegel, David; Schneider, Donald P.; Schuster, William J.; Schwope, Axel; Seo, Hee-Jong; Serenelli, Aldo; Shen, Shiyin; Shen, Yue; Shetrone, Matthew; Shull, Michael; Silva Aguirre, Víctor; Simon, Joshua D.; Skrutskie, Mike; Slosar, Anže; Smethurst, Rebecca; Smith, Verne; Sobeck, Jennifer; Somers, Garrett; Souter, Barbara J.; Souto, Diogo; Spindler, Ashley; Stark, David V.; Stassun, Keivan; Steinmetz, Matthias; Stello, Dennis; Storchi-Bergmann, Thaisa; Streblyanska, Alina; Stringfellow, Guy S.; Suárez, Genaro; Sun, Jing; Szigeti, Laszlo; Taghizadeh-Popp, Manuchehr; Talbot, Michael S.; Tang, Baitian; Tao, Charling; Tayar, Jamie; Tembe, Mita; Teske, Johanna; Thakar, Aniruddha R.; Thomas, Daniel; Tissera, Patricia; Tojeiro, Rita; Tremonti, Christy; Troup, Nicholas W.; Urry, Meg; Valenzuela, O.; van den Bosch, Remco; Vargas-González, Jaime; Vargas-Magaña, Mariana; Vazquez, Jose Alberto; Villanova, Sandro; Vogt, Nicole; Wake, David; Wang, Yuting; Weaver, Benjamin Alan; Weijmans, Anne-Marie; Weinberg, David H.; Westfall, Kyle B.; Whelan, David G.; Wilcots, Eric; Wild, Vivienne; Williams, Rob A.; Wilson, John; Wood-Vasey, W. M.; Wylezalek, Dominika; Xiao, Ting; Yan, Renbin; Yang, Meng; Ybarra, Jason E.; Yèche, Christophe; Zakamska, Nadia; Zamora, Olga; Zarrouk, Pauline; Zasowski, Gail; Zhang, Kai; Zhao, Cheng; Zhao, Gong-Bo; Zheng, Zheng; Zheng, Zheng; Zhou, Zhi-Min; Zhu, Guangtun; Zinn, Joel C.; Zou, Hu

2018-04-01

The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since 2014 July. This paper describes the second data release from this phase, and the 14th from SDSS overall (making this Data Release Fourteen or DR14). This release makes the data taken by SDSS-IV in its first two years of operation (2014–2016 July) public. Like all previous SDSS releases, DR14 is cumulative, including the most recent reductions and calibrations of all data taken by SDSS since the first phase began operations in 2000. New in DR14 is the first public release of data from the extended Baryon Oscillation Spectroscopic Survey; the first data from the second phase of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2), including stellar parameter estimates from an innovative data-driven machine-learning algorithm known as “The Cannon” and almost twice as many data cubes from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous release (N = 2812 in total). This paper describes the location and format of the publicly available data from the SDSS-IV surveys. We provide references to the important technical papers describing how these data have been taken (both targeting and observation details) and processed for scientific use. The SDSS web site (www.sdss.org) has been updated for this release and provides links to data downloads, as well as tutorials and examples of data use. SDSS-IV is planning to continue to collect astronomical data until 2020 and will be followed by SDSS-V.

The Sloan Lens ACS Survey. I. A large spectroscopically selected sample of massive early-type lens galaxies

NARCIS (Netherlands)

Bolton, AS; Burles, S; Koopmans, LVE; Treu, T; Moustakas, LA

2006-01-01

The Sloan Lens ACS (SLACS) Survey is an efficient Hubble Space Telescope (HST) Snapshot imaging survey for new galaxy-scale strong gravitational lenses. The targeted lens candidates are selected spectroscopically from the Sloan Digital Sky Survey (SDSS) database of galaxy spectra for having multiple

The Sloan Digital Sky Survey Quasar Catalog: Fourteenth data release

Science.gov (United States)

Pâris, Isabelle; Petitjean, Patrick; Aubourg, Éric; Myers, Adam D.; Streblyanska, Alina; Lyke, Brad W.; Anderson, Scott F.; Armengaud, Éric; Bautista, Julian; Blanton, Michael R.; Blomqvist, Michael; Brinkmann, Jonathan; Brownstein, Joel R.; Brandt, William Nielsen; Burtin, Étienne; Dawson, Kyle; de la Torre, Sylvain; Georgakakis, Antonis; Gil-Marín, Héctor; Green, Paul J.; Hall, Patrick B.; Kneib, Jean-Paul; LaMassa, Stephanie M.; Le Goff, Jean-Marc; MacLeod, Chelsea; Mariappan, Vivek; McGreer, Ian D.; Merloni, Andrea; Noterdaeme, Pasquier; Palanque-Delabrouille, Nathalie; Percival, Will J.; Ross, Ashley J.; Rossi, Graziano; Schneider, Donald P.; Seo, Hee-Jong; Tojeiro, Rita; Weaver, Benjamin A.; Weijmans, Anne-Marie; Yèche, Christophe; Zarrouk, Pauline; Zhao, Gong-Bo

2018-05-01

We present the data release 14 Quasar catalog (DR14Q) from the extended Baryon Oscillation Spectroscopic Survey (eBOSS) of the Sloan Digital Sky Survey IV (SDSS-IV). This catalog includes all SDSS-IV/eBOSS objects that were spectroscopically targeted as quasar candidates and that are confirmed as quasars via a new automated procedure combined with a partial visual inspection of spectra, have luminosities Mi [z = 2] < -20.5 (in a Λ CDM cosmology with H0 = 70 km s-1 Mpc-1, Ω M =0.3, and Ω Λ = 0.7), and either display at least one emission line with a full width at half maximum larger than 500 km s-1 or, if not, have interesting/complex absorption features. The catalog also includes previously spectroscopically-confirmed quasars from SDSS-I, II, and III. The catalog contains 526 356 quasars (144 046 are new discoveries since the beginning of SDSS-IV) detected over 9376 deg2 (2044 deg2 having new spectroscopic data available) with robust identification and redshift measured by a combination of principal component eigenspectra. The catalog is estimated to have about 0.5% contamination. Redshifts are provided for the Mg II emission line. The catalog identifies 21 877 broad absorption line quasars and lists their characteristics. For each object, the catalog presents five-band (u, g, r, i, z) CCD-based photometry with typical accuracy of 0.03 mag. The catalog also contains X-ray, ultraviolet, near-infrared, and radio emission properties of the quasars, when available, from other large-area surveys. The calibrated digital spectra, covering the wavelength region 3610-10 140 Å at a spectral resolution in the range 1300 < R < 2500, can be retrieved from the SDSS Science Archiver Server. http://www.sdss.org/dr14/algorithms/qso_catalog

CHARACTERIZATION OF SLOAN DIGITAL SKY SURVEY STELLAR PHOTOMETRY

International Nuclear Information System (INIS)

Fukugita, Masataka; Yasuda, Naoki; Doi, Mamoru; Gunn, James E.; York, Donald G.

2011-01-01

We study the photometric properties of stars in the data archive of the Sloan Digital Sky Survey (SDSS), the prime aim being to understand the photometric calibration over the entire data set. It is confirmed that the photometric calibration of point sources is accurately on the system defined by the SDSS standard stars. We have also confirmed that the photometric synthesis of the SDSS spectrophotometric data gives broadband fluxes that agree with the photometry with errors of no more than 0.04 mag and little systematic tilt with wavelength. This verifies that the response functions of the 2.5 m telescope system are well characterized. We locate stars in the SDSS photometric system, so that stars can roughly be classified into spectral classes from the color information. We show how metallicity and surface gravity affect colors, and that stars contained in the SDSS general catalog, plotted in color space, show a distribution that matches well with what is anticipated from the variations of metallicity and surface gravity. The color-color plots are perfectly consistent among the three samples-stars in the SDSS general catalog, SDSS standard stars, and spectrophotometric stars of Gunn and Stryker-especially when some considerations are taken into account of the differences (primarily metallicity) of the samples. We show that the g - r-inverse temperature relation is tight and can be used as a good estimator of the effective temperature of stars over a fairly wide range of effective temperatures. We also confirm that the colors of G2V stars in the SDSS photometric system match well with the Sun.

DISTRIBUTION OF MAXIMAL LUMINOSITY OF GALAXIES IN THE SLOAN DIGITAL SKY SURVEY

Energy Technology Data Exchange (ETDEWEB)

Taghizadeh-Popp, M.; Szalay, A. S. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Ozogany, K.; Racz, Z. [Institute for Theoretical Physics-HAS, Eoetvoes University, Pazmany setany 1/a, 1117 Budapest (Hungary); Regoes, E., E-mail: mtaghiza@pha.jhu.edu [European Laboratory for Particle Physics (CERN), Geneva (Switzerland)

2012-11-10

Extreme value statistics is applied to the distribution of galaxy luminosities in the Sloan Digital Sky Survey. We analyze the DR8 Main Galaxy Sample (MGS), as well as the luminous red galaxies (LRGs). Maximal luminosities are sampled from batches consisting of elongated pencil beams in the radial direction of sight. For the MGS, results suggest a small and positive tail index {xi}, effectively ruling out the possibility of having a finite maximum cutoff luminosity, and implying that the luminosity distribution function may decay as a power law at the high-luminosity end. Assuming, however, {xi} = 0, a non-parametric comparison of the maximal luminosities with the Fisher-Tippett-Gumbel distribution (limit distribution for variables distributed by the Schechter fit) indicates a good agreement provided that uncertainties arising from both the finite batch size and the batch-size distribution are accounted for. For a volume-limited sample of LRGs, results show that they can be described as being the extremes of a luminosity distribution with an exponentially decaying tail, provided that the uncertainties related to batch-size distribution are taken care of.

GALAXY ZOO MORPHOLOGY AND PHOTOMETRIC REDSHIFTS IN THE SLOAN DIGITAL SKY SURVEY

International Nuclear Information System (INIS)

Way, M. J.

2011-01-01

It has recently been demonstrated that one can accurately derive galaxy morphology from particular primary and secondary isophotal shape estimates in the Sloan Digital Sky Survey (SDSS) imaging catalog. This was accomplished by applying Machine Learning techniques to the Galaxy Zoo morphology catalog. Using the broad bandpass photometry of the SDSS in combination with precise knowledge of galaxy morphology should help in estimating more accurate photometric redshifts for galaxies. Using the Galaxy Zoo separation for spirals and ellipticals in combination with SDSS photometry we attempt to calculate photometric redshifts. In the best case we find that the root-mean-square error for luminous red galaxies classified as ellipticals is as low as 0.0118. Given these promising results we believe better photometric redshift estimates for all galaxies in the SDSS (∼350 million) will be feasible if researchers can also leverage their derived morphologies via Machine Learning. These initial results look to be promising for those interested in estimating weak lensing, baryonic acoustic oscillation, and other fields dependent upon accurate photometric redshifts.

THE ELEVENTH AND TWELFTH DATA RELEASES OF THE SLOAN DIGITAL SKY SURVEY: FINAL DATA FROM SDSS-III

International Nuclear Information System (INIS)

Alam, Shadab; Albareti, Franco D.; Prieto, Carlos Allende; Anders, F.; Anderson, Scott F.; Anderton, Timothy; Andrews, Brett H.; Armengaud, Eric; Aubourg, Éric; Bautista, Julian E.; Bailey, Stephen; Basu, Sarbani; Beaton, Rachael L.; Beers, Timothy C.

2015-01-01

The third generation of the Sloan Digital Sky Survey (SDSS-III) took data from 2008 to 2014 using the original SDSS wide-field imager, the original and an upgraded multi-object fiber-fed optical spectrograph, a new near-infrared high-resolution spectrograph, and a novel optical interferometer. All of the data from SDSS-III are now made public. In particular, this paper describes Data Release 11 (DR11) including all data acquired through 2013 July, and Data Release 12 (DR12) adding data acquired through 2014 July (including all data included in previous data releases), marking the end of SDSS-III observing. Relative to our previous public release (DR10), DR12 adds one million new spectra of galaxies and quasars from the Baryon Oscillation Spectroscopic Survey (BOSS) over an additional 3000 deg 2 of sky, more than triples the number of H-band spectra of stars as part of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE), and includes repeated accurate radial velocity measurements of 5500 stars from the Multi-object APO Radial Velocity Exoplanet Large-area Survey (MARVELS). The APOGEE outputs now include the measured abundances of 15 different elements for each star. In total, SDSS-III added 5200 deg 2 of ugriz imaging; 155,520 spectra of 138,099 stars as part of the Sloan Exploration of Galactic Understanding and Evolution 2 (SEGUE-2) survey; 2,497,484 BOSS spectra of 1,372,737 galaxies, 294,512 quasars, and 247,216 stars over 9376 deg 2 ; 618,080 APOGEE spectra of 156,593 stars; and 197,040 MARVELS spectra of 5513 stars. Since its first light in 1998, SDSS has imaged over 1/3 of the Celestial sphere in five bands and obtained over five million astronomical spectra

The Eleventh and Twelfth Data Releases of the Sloan Digital Sky Survey: Final Data from SDSS-III

Science.gov (United States)

Alam, Shadab; Albareti, Franco D.; Allende Prieto, Carlos; Anders, F.; Anderson, Scott F.; Anderton, Timothy; Andrews, Brett H.; Armengaud, Eric; Aubourg, Éric; Bailey, Stephen; Basu, Sarbani; Bautista, Julian E.; Beaton, Rachael L.; Beers, Timothy C.; Bender, Chad F.; Berlind, Andreas A.; Beutler, Florian; Bhardwaj, Vaishali; Bird, Jonathan C.; Bizyaev, Dmitry; Blake, Cullen H.; Blanton, Michael R.; Blomqvist, Michael; Bochanski, John J.; Bolton, Adam S.; Bovy, Jo; Shelden Bradley, A.; Brandt, W. N.; Brauer, D. E.; Brinkmann, J.; Brown, Peter J.; Brownstein, Joel R.; Burden, Angela; Burtin, Etienne; Busca, Nicolás G.; Cai, Zheng; Capozzi, Diego; Carnero Rosell, Aurelio; Carr, Michael A.; Carrera, Ricardo; Chambers, K. C.; Chaplin, William James; Chen, Yen-Chi; Chiappini, Cristina; Chojnowski, S. Drew; Chuang, Chia-Hsun; Clerc, Nicolas; Comparat, Johan; Covey, Kevin; Croft, Rupert A. C.; Cuesta, Antonio J.; Cunha, Katia; da Costa, Luiz N.; Da Rio, Nicola; Davenport, James R. A.; Dawson, Kyle S.; De Lee, Nathan; Delubac, Timothée; Deshpande, Rohit; Dhital, Saurav; Dutra-Ferreira, Letícia; Dwelly, Tom; Ealet, Anne; Ebelke, Garrett L.; Edmondson, Edward M.; Eisenstein, Daniel J.; Ellsworth, Tristan; Elsworth, Yvonne; Epstein, Courtney R.; Eracleous, Michael; Escoffier, Stephanie; Esposito, Massimiliano; Evans, Michael L.; Fan, Xiaohui; Fernández-Alvar, Emma; Feuillet, Diane; Filiz Ak, Nurten; Finley, Hayley; Finoguenov, Alexis; Flaherty, Kevin; Fleming, Scott W.; Font-Ribera, Andreu; Foster, Jonathan; Frinchaboy, Peter M.; Galbraith-Frew, J. G.; García, Rafael A.; García-Hernández, D. A.; García Pérez, Ana E.; Gaulme, Patrick; Ge, Jian; Génova-Santos, R.; Georgakakis, A.; Ghezzi, Luan; Gillespie, Bruce A.; Girardi, Léo; Goddard, Daniel; Gontcho, Satya Gontcho A.; González Hernández, Jonay I.; Grebel, Eva K.; Green, Paul J.; Grieb, Jan Niklas; Grieves, Nolan; Gunn, James E.; Guo, Hong; Harding, Paul; Hasselquist, Sten; Hawley, Suzanne L.; Hayden, Michael; Hearty, Fred R.; Hekker, Saskia; Ho, Shirley; Hogg, David W.; Holley-Bockelmann, Kelly; Holtzman, Jon A.; Honscheid, Klaus; Huber, Daniel; Huehnerhoff, Joseph; Ivans, Inese I.; Jiang, Linhua; Johnson, Jennifer A.; Kinemuchi, Karen; Kirkby, David; Kitaura, Francisco; Klaene, Mark A.; Knapp, Gillian R.; Kneib, Jean-Paul; Koenig, Xavier P.; Lam, Charles R.; Lan, Ting-Wen; Lang, Dustin; Laurent, Pierre; Le Goff, Jean-Marc; Leauthaud, Alexie; Lee, Khee-Gan; Lee, Young Sun; Licquia, Timothy C.; Liu, Jian; Long, Daniel C.; López-Corredoira, Martín; Lorenzo-Oliveira, Diego; Lucatello, Sara; Lundgren, Britt; Lupton, Robert H.; Mack, Claude E., III; Mahadevan, Suvrath; Maia, Marcio A. G.; Majewski, Steven R.; Malanushenko, Elena; Malanushenko, Viktor; Manchado, A.; Manera, Marc; Mao, Qingqing; Maraston, Claudia; Marchwinski, Robert C.; Margala, Daniel; Martell, Sarah L.; Martig, Marie; Masters, Karen L.; Mathur, Savita; McBride, Cameron K.; McGehee, Peregrine M.; McGreer, Ian D.; McMahon, Richard G.; Ménard, Brice; Menzel, Marie-Luise; Merloni, Andrea; Mészáros, Szabolcs; Miller, Adam A.; Miralda-Escudé, Jordi; Miyatake, Hironao; Montero-Dorta, Antonio D.; More, Surhud; Morganson, Eric; Morice-Atkinson, Xan; Morrison, Heather L.; Mosser, Benôit; Muna, Demitri; Myers, Adam D.; Nandra, Kirpal; Newman, Jeffrey A.; Neyrinck, Mark; Nguyen, Duy Cuong; Nichol, Robert C.; Nidever, David L.; Noterdaeme, Pasquier; Nuza, Sebastián E.; O'Connell, Julia E.; O'Connell, Robert W.; O'Connell, Ross; Ogando, Ricardo L. C.; Olmstead, Matthew D.; Oravetz, Audrey E.; Oravetz, Daniel J.; Osumi, Keisuke; Owen, Russell; Padgett, Deborah L.; Padmanabhan, Nikhil; Paegert, Martin; Palanque-Delabrouille, Nathalie; Pan, Kaike; Parejko, John K.; Pâris, Isabelle; Park, Changbom; Pattarakijwanich, Petchara; Pellejero-Ibanez, M.; Pepper, Joshua; Percival, Will J.; Pérez-Fournon, Ismael; P´rez-Ra`fols, Ignasi; Petitjean, Patrick; Pieri, Matthew M.; Pinsonneault, Marc H.; Porto de Mello, Gustavo F.; Prada, Francisco; Prakash, Abhishek; Price-Whelan, Adrian M.; Protopapas, Pavlos; Raddick, M. Jordan; Rahman, Mubdi; Reid, Beth A.; Rich, James; Rix, Hans-Walter; Robin, Annie C.; Rockosi, Constance M.; Rodrigues, Thaíse S.; Rodríguez-Torres, Sergio; Roe, Natalie A.; Ross, Ashley J.; Ross, Nicholas P.; Rossi, Graziano; Ruan, John J.; Rubiño-Martín, J. A.; Rykoff, Eli S.; Salazar-Albornoz, Salvador; Salvato, Mara; Samushia, Lado; Sánchez, Ariel G.; Santiago, Basílio; Sayres, Conor; Schiavon, Ricardo P.; Schlegel, David J.; Schmidt, Sarah J.; Schneider, Donald P.; Schultheis, Mathias; Schwope, Axel D.; Scóccola, C. G.; Scott, Caroline; Sellgren, Kris; Seo, Hee-Jong; Serenelli, Aldo; Shane, Neville; Shen, Yue; Shetrone, Matthew; Shu, Yiping; Silva Aguirre, V.; Sivarani, Thirupathi; Skrutskie, M. F.; Slosar, Anže; Smith, Verne V.; Sobreira, Flávia; Souto, Diogo; Stassun, Keivan G.; Steinmetz, Matthias; Stello, Dennis; Strauss, Michael A.; Streblyanska, Alina; Suzuki, Nao; Swanson, Molly E. C.; Tan, Jonathan C.; Tayar, Jamie; Terrien, Ryan C.; Thakar, Aniruddha R.; Thomas, Daniel; Thomas, Neil; Thompson, Benjamin A.; Tinker, Jeremy L.; Tojeiro, Rita; Troup, Nicholas W.; Vargas-Magaña, Mariana; Vazquez, Jose A.; Verde, Licia; Viel, Matteo; Vogt, Nicole P.; Wake, David A.; Wang, Ji; Weaver, Benjamin A.; Weinberg, David H.; Weiner, Benjamin J.; White, Martin; Wilson, John C.; Wisniewski, John P.; Wood-Vasey, W. M.; Ye`che, Christophe; York, Donald G.; Zakamska, Nadia L.; Zamora, O.; Zasowski, Gail; Zehavi, Idit; Zhao, Gong-Bo; Zheng, Zheng; Zhou, Xu; Zhou, Zhimin; Zou, Hu; Zhu, Guangtun

2015-07-01

The third generation of the Sloan Digital Sky Survey (SDSS-III) took data from 2008 to 2014 using the original SDSS wide-field imager, the original and an upgraded multi-object fiber-fed optical spectrograph, a new near-infrared high-resolution spectrograph, and a novel optical interferometer. All of the data from SDSS-III are now made public. In particular, this paper describes Data Release 11 (DR11) including all data acquired through 2013 July, and Data Release 12 (DR12) adding data acquired through 2014 July (including all data included in previous data releases), marking the end of SDSS-III observing. Relative to our previous public release (DR10), DR12 adds one million new spectra of galaxies and quasars from the Baryon Oscillation Spectroscopic Survey (BOSS) over an additional 3000 deg2 of sky, more than triples the number of H-band spectra of stars as part of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE), and includes repeated accurate radial velocity measurements of 5500 stars from the Multi-object APO Radial Velocity Exoplanet Large-area Survey (MARVELS). The APOGEE outputs now include the measured abundances of 15 different elements for each star. In total, SDSS-III added 5200 deg2 of ugriz imaging; 155,520 spectra of 138,099 stars as part of the Sloan Exploration of Galactic Understanding and Evolution 2 (SEGUE-2) survey; 2,497,484 BOSS spectra of 1,372,737 galaxies, 294,512 quasars, and 247,216 stars over 9376 deg2; 618,080 APOGEE spectra of 156,593 stars; and 197,040 MARVELS spectra of 5513 stars. Since its first light in 1998, SDSS has imaged over 1/3 of the Celestial sphere in five bands and obtained over five million astronomical spectra.

The eleventh and twelfth data release of the Sloan Digital Sky Survey: Final data from SDSS-III

Energy Technology Data Exchange (ETDEWEB)

Alam, Shadab; Albareti, Franco D.; Prieto, Carlos Allende; Anders, F.; Anderson, Scott F.; Anderton, Timothy; Andrews, Brett H.; Armengaud, Eric; Aubourg, Éric; Bailey, Stephen; Basu, Sarbani; Bautista, Julian E.; Beaton, Rachael L.; Beers, Timothy C.; Bender, Chad F.; Berlind, Andreas A.; Beutler, Florian; Bhardwaj, Vaishali; Bird, Jonathan C.; Bizyaev, Dmitry; Blake, Cullen H.; Blanton, Michael R.; Blomqvist, Michael; Bochanski, John J.; Bolton, Adam S.; Bovy, Jo; Bradley, A. Shelden; Brandt, W. N.; Brauer, D. E.; Brinkmann, J.; Brown, Peter J.; Brownstein, Joel R.; Burden, Angela; Burtin, Etienne; Busca, Nicolás G.; Cai, Zheng; Capozzi, Diego; Rosell, Aurelio Carnero; Carr, Michael A.; Carrera, Ricardo; Chambers, K. C.; Chaplin, William James; Chen, Yen-Chi; Chiappini, Cristina; Chojnowski, S. Drew; Chuang, Chia-Hsun; Clerc, Nicolas; Comparat, Johan; Covey, Kevin; Croft, Rupert A. C.; Cuesta, Antonio J.; Cunha, Katia; Costa, Luiz N. da; Rio, Nicola Da; Davenport, James R. A.; Dawson, Kyle S.; Lee, Nathan De; Delubac, Timothée; Deshpande, Rohit; Dhital, Saurav; Dutra-Ferreira, Letícia; Dwelly, Tom; Ealet, Anne; Ebelke, Garrett L.; Edmondson, Edward M.; Eisenstein, Daniel J.; Ellsworth, Tristan; Elsworth, Yvonne; Epstein, Courtney R.; Eracleous, Michael; Escoffier, Stephanie; Esposito, Massimiliano; Evans, Michael L.; Fan, Xiaohui; Fernández-Alvar, Emma; Feuillet, Diane; Ak, Nurten Filiz; Finley, Hayley; Finoguenov, Alexis; Flaherty, Kevin; Fleming, Scott W.; Font-Ribera, Andreu; Foster, Jonathan; Frinchaboy, Peter M.; Galbraith-Frew, J. G.; García, Rafael A.; García-Hernández, D. A.; Pérez, Ana E. García; Gaulme, Patrick; Ge, Jian; Génova-Santos, R.; Georgakakis, A.; Ghezzi, Luan; Gillespie, Bruce A.; Girardi, Léo; Goddard, Daniel; Gontcho, Satya Gontcho A.; Hernández, Jonay I. González; Grebel, Eva K.; Green, Paul J.; Grieb, Jan Niklas; Grieves, Nolan; Gunn, James E.; Guo, Hong; Harding, Paul; Hasselquist, Sten; Hawley, Suzanne L.; Hayden, Michael; Hearty, Fred R.; Hekker, Saskia; Ho, Shirley; Hogg, David W.; Holley-Bockelmann, Kelly; Holtzman, Jon A.; Honscheid, Klaus; Huber, Daniel; Huehnerhoff, Joseph; Ivans, Inese I.; Jiang, Linhua; Johnson, Jennifer A.; Kinemuchi, Karen; Kirkby, David; Kitaura, Francisco; Klaene, Mark A.; Knapp, Gillian R.; Kneib, Jean-Paul; Koenig, Xavier P.; Lam, Charles R.; Lan, Ting-Wen; Lang, Dustin; Laurent, Pierre; Goff, Jean-Marc Le; Leauthaud, Alexie; Lee, Khee-Gan; Lee, Young Sun; Licquia, Timothy C.; Liu, Jian; Long, Daniel C.; López-Corredoira, Martín; Lorenzo-Oliveira, Diego; Lucatello, Sara; Lundgren, Britt; Lupton, Robert H.; III, Claude E. Mack; Mahadevan, Suvrath; Maia, Marcio A. G.; Majewski, Steven R.; Malanushenko, Elena; Malanushenko, Viktor; Manchado, A.; Manera, Marc; Mao, Qingqing; Maraston, Claudia; Marchwinski, Robert C.; Margala, Daniel; Martell, Sarah L.; Martig, Marie; Masters, Karen L.; Mathur, Savita; McBride, Cameron K.; McGehee, Peregrine M.; McGreer, Ian D.; McMahon, Richard G.; Ménard, Brice; Menzel, Marie-Luise; Merloni, Andrea; Mészáros, Szabolcs; Miller, Adam A.; Miralda-Escudé, Jordi; Miyatake, Hironao; Montero-Dorta, Antonio D.; More, Surhud; Morganson, Eric; Morice-Atkinson, Xan; Morrison, Heather L.; Mosser, Benôit; Muna, Demitri; Myers, Adam D.; Nandra, Kirpal; Newman, Jeffrey A.; Neyrinck, Mark; Nguyen, Duy Cuong; Nichol, Robert C.; Nidever, David L.; Noterdaeme, Pasquier; Nuza, Sebastián E.; O’Connell, Julia E.; O’Connell, Robert W.; O’Connell, Ross; Ogando, Ricardo L. C.; Olmstead, Matthew D.; Oravetz, Audrey E.; Oravetz, Daniel J.; Osumi, Keisuke; Owen, Russell; Padgett, Deborah L.; Padmanabhan, Nikhil; Paegert, Martin; Palanque-Delabrouille, Nathalie; Pan, Kaike; Parejko, John K.; Pâris, Isabelle; Park, Changbom; Pattarakijwanich, Petchara; Pellejero-Ibanez, M.; Pepper, Joshua; Percival, Will J.; Pérez-Fournon, Ismael; Pe´rez-Ra`fols, Ignasi; Petitjean, Patrick; Pieri, Matthew M.; Pinsonneault, Marc H.; Mello, Gustavo F. Porto de; Prada, Francisco; Prakash, Abhishek; Price-Whelan, Adrian M.; Protopapas, Pavlos; Raddick, M. Jordan; Rahman, Mubdi; Reid, Beth A.; Rich, James; Rix, Hans-Walter; Robin, Annie C.; Rockosi, Constance M.; Rodrigues, Thaíse S.; Rodríguez-Torres, Sergio; Roe, Natalie A.; Ross, Ashley J.; Ross, Nicholas P.; Rossi, Graziano; Ruan, John J.; Rubiño-Martín, J. A.; Rykoff, Eli S.; Salazar-Albornoz, Salvador; Salvato, Mara; Samushia, Lado; Sánchez, Ariel G.; Santiago, Basílio; Sayres, Conor; Schiavon, Ricardo P.; Schlegel, David J.; Schmidt, Sarah J.; Schneider, Donald P.; Schultheis, Mathias; Schwope, Axel D.; Scóccola, C. G.; Scott, Caroline; Sellgren, Kris; Seo, Hee-Jong; Serenelli, Aldo; Shane, Neville; Shen, Yue; Shetrone, Matthew; Shu, Yiping; Aguirre, V. Silva; Sivarani, Thirupathi; Skrutskie, M. F.; Slosar, Anže; Smith, Verne V.; Sobreira, Flávia; Souto, Diogo; Stassun, Keivan G.; Steinmetz, Matthias; Stello, Dennis; Strauss, Michael A.; Streblyanska, Alina; Suzuki, Nao; Swanson, Molly E. C.; Tan, Jonathan C.; Tayar, Jamie; Terrien, Ryan C.; Thakar, Aniruddha R.; Thomas, Daniel; Thomas, Neil; Thompson, Benjamin A.; Tinker, Jeremy L.; Tojeiro, Rita; Troup, Nicholas W.; Vargas-Magaña, Mariana; Vazquez, Jose A.; Verde, Licia; Viel, Matteo; Vogt, Nicole P.; Wake, David A.; Wang, Ji; Weaver, Benjamin A.; Weinberg, David H.; Weiner, Benjamin J.; White, Martin; Wilson, John C.; Wisniewski, John P.; Wood-Vasey, W. M.; Ye`che, Christophe; York, Donald G.; Zakamska, Nadia L.; Zamora, O.; Zasowski, Gail; Zehavi, Idit; Zhao, Gong-Bo; Zheng, Zheng; Zhou (周旭), Xu; Zhou (周志民), Zhimin; Zou (邹虎), Hu; Zhu, Guangtun

2015-07-20

The third generation of the Sloan Digital Sky Survey (SDSS-III) took data from 2008 to 2014 using the original SDSS wide-field imager, the original and an upgraded multi-object fiber-fed optical spectrograph, a new near-infrared high-resolution spectrograph, and a novel optical interferometer. All of the data from SDSS-III are now made public. In particular, this paper describes Data Release 11 (DR11) including all data acquired through 2013 July, and Data Release 12 (DR12) adding data acquired through 2014 July (including all data included in previous data releases), marking the end of SDSS-III observing. Relative to our previous public release (DR10), DR12 adds one million new spectra of galaxies and quasars from the Baryon Oscillation Spectroscopic Survey (BOSS) over an additional 3000 deg² of sky, more than triples the number of H-band spectra of stars as part of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE), and includes repeated accurate radial velocity measurements of 5500 stars from the Multi-object APO Radial Velocity Exoplanet Large-area Survey (MARVELS). The APOGEE outputs now include the measured abundances of 15 different elements for each star. In total, SDSS-III added 5200 deg² of ugriz imaging; 155,520 spectra of 138,099 stars as part of the Sloan Exploration of Galactic Understanding and Evolution 2 (SEGUE-2) survey; 2,497,484 BOSS spectra of 1,372,737 galaxies, 294,512 quasars, and 247,216 stars over 9376 deg²; 618,080 APOGEE spectra of 156,593 stars; and 197,040 MARVELS spectra of 5513 stars. Since its first light in 1998, SDSS has imaged over 1/3 of the Celestial sphere in five bands and obtained over five million astronomical spectra.

The Data Release of the Sloan Digital Sky Survey-II Supernova Survey

Science.gov (United States)

Sako, Masao; Bassett, Bruce; Becker, Andrew C.; Brown, Peter J.; Campbell, Heather; Wolf, Rachel; Cinabro, David; D’Andrea, Chris B.; Dawson, Kyle S.; DeJongh, Fritz; Depoy, Darren L.; Dilday, Ben; Doi, Mamoru; Filippenko, Alexei V.; Fischer, John A.; Foley, Ryan J.; Frieman, Joshua A.; Galbany, Lluis; Garnavich, Peter M.; Goobar, Ariel; Gupta, Ravi R.; Hill, Gary J.; Hayden, Brian T.; Hlozek, Renée; Holtzman, Jon A.; Hopp, Ulrich; Jha, Saurabh W.; Kessler, Richard; Kollatschny, Wolfram; Leloudas, Giorgos; Marriner, John; Marshall, Jennifer L.; Miquel, Ramon; Morokuma, Tomoki; Mosher, Jennifer; Nichol, Robert C.; Nordin, Jakob; Olmstead, Matthew D.; Östman, Linda; Prieto, Jose L.; Richmond, Michael; Romani, Roger W.; Sollerman, Jesper; Stritzinger, Max; Schneider, Donald P.; Smith, Mathew; Wheeler, J. Craig; Yasuda, Naoki; Zheng, Chen

2018-06-01

This paper describes the data release of the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey conducted between 2005 and 2007. Light curves, spectra, classifications, and ancillary data are presented for 10,258 variable and transient sources discovered through repeat ugriz imaging of SDSS Stripe 82, a 300 deg2 area along the celestial equator. This data release is comprised of all transient sources brighter than r ≃ 22.5 mag with no history of variability prior to 2004. Dedicated spectroscopic observations were performed on a subset of 889 transients, as well as spectra for thousands of transient host galaxies using the SDSS-III BOSS spectrographs. Photometric classifications are provided for the candidates with good multi-color light curves that were not observed spectroscopically, using host galaxy redshift information when available. From these observations, 4607 transients are either spectroscopically confirmed, or likely to be, supernovae, making this the largest sample of supernova candidates ever compiled. We present a new method for SN host-galaxy identification and derive host-galaxy properties including stellar masses, star formation rates, and the average stellar population ages from our SDSS multi-band photometry. We derive SALT2 distance moduli for a total of 1364 SN Ia with spectroscopic redshifts as well as photometric redshifts for a further 624 purely photometric SN Ia candidates. Using the spectroscopically confirmed subset of the three-year SDSS-II SN Ia sample and assuming a flat ΛCDM cosmology, we determine Ω M = 0.315 ± 0.093 (statistical error only) and detect a non-zero cosmological constant at 5.7σ.

The Data Release of the Sloan Digital Sky Survey-II Supernova Survey

Energy Technology Data Exchange (ETDEWEB)

Sako, Masao; et al.

2014-01-14

This paper describes the data release of the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey conducted between 2005 and 2007. Light curves, spectra, classifications, and ancillary data are presented for 10,258 variable and transient sources discovered through repeat ugriz imaging of SDSS Stripe 82, a 300 deg2 area along the celestial equator. This data release is comprised of all transient sources brighter than r~22.5 mag with no history of variability prior to 2004. Dedicated spectroscopic observations were performed on a subset of 889 transients, as well as spectra for thousands of transient host galaxies using the SDSS-III BOSS spectrographs. Photometric classifications are provided for the candidates with good multi-color light curves that were not observed spectroscopically. From these observations, 4607 transients are either spectroscopically confirmed, or likely to be, supernovae, making this the largest sample of supernova candidates ever compiled. We present a new method for SN host-galaxy identification and derive host-galaxy properties including stellar masses, star-formation rates, and the average stellar population ages from our SDSS multi-band photometry. We derive SALT2 distance moduli for a total of 1443 SN Ia with spectroscopic redshifts as well as photometric redshifts for a further 677 purely-photometric SN Ia candidates. Using the spectroscopically confirmed subset of the three-year SDSS-II SN Ia sample and assuming a flat Lambda-CDM cosmology, we determine Omega_M = 0.315 +/- 0.093 (statistical error only) and detect a non-zero cosmological constant at 5.7 sigmas.

XMM-NEWTON AND OPTICAL OBSERVATIONS OF CATACLYSMIC VARIABLES FROM THE SLOAN DIGITAL SKY SURVEY

International Nuclear Information System (INIS)

Hilton, Eric J.; Szkody, Paula; Mukadam, Anjum; Henden, Arne; Dillon, William; Schmidt, Gary D.

2009-01-01

We report on XMM-Newton and optical results for six cataclysmic variables that were selected from Sloan Digital Sky Survey (SDSS) spectra because they showed strong He II emission lines, indicative of being candidates for containing white dwarfs with strong magnetic fields. While high X-ray background rates prevented optimum results, we are able to confirm SDSS J233325.92+152222.1 as an intermediate polar from its strong pulse signature at 21 minutes and its obscured hard X-ray spectrum. Ground-based circular polarization and photometric observations were also able to confirm SDSS J142256.31 - 022108.1 as a polar with a period near 4 hr. Photometry of SDSS J083751.00+383012.5 and SDSS J093214.82+495054.7 solidifies the orbital period of the former as 3.18 hr and confirms the latter as a high-inclination system with deep eclipses.

Extreme Variability Quasars from the Sloan Digital Sky Survey and the Dark Energy Survey

Science.gov (United States)

Rumbaugh, N.; Shen, Yue; Morganson, Eric; Liu, Xin; Banerji, M.; McMahon, R. G.; Abdalla, F. B.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Capozzi, D.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Cunha, C. E.; D’Andrea, C. B.; da Costa, L. N.; DePoy, D. L.; Desai, S.; Doel, P.; Frieman, J.; García-Bellido, J.; Gruen, D.; Gruendl, R. A.; Gschwend, J.; Gutierrez, G.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuhlmann, S.; Kuropatkin, N.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Martini, P.; Menanteau, F.; Plazas, A. A.; Reil, K.; Roodman, A.; Sanchez, E.; Scarpine, V.; Schindler, R.; Schubnell, M.; Sheldon, E.; Smith, M.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Walker, A. R.; Wester, W.; (DES Collaboration

2018-02-01

We perform a systematic search for long-term extreme variability quasars (EVQs) in the overlapping Sloan Digital Sky Survey and 3 Year Dark Energy Survey imaging, which provide light curves spanning more than 15 years. We identified ∼1000 EVQs with a maximum change in g-band magnitude of more than 1 mag over this period, about 10% of all quasars searched. The EVQs have L bol ∼ 1045–1047 erg s‑1 and L/L Edd ∼ 0.01–1. Accounting for selection effects, we estimate an intrinsic EVQ fraction of ∼30%–50% among all g≲ 22 quasars over a baseline of ∼15 yr. We performed detailed multi-wavelength, spectral, and variability analyses for the EVQs and compared them to their parent quasar sample. We found that EVQs are distinct from a control sample of quasars matched in redshift and optical luminosity: (1) their UV broad emission lines have larger equivalent widths; (2) their Eddington ratios are systematically lower; and (3) they are more variable on all timescales. The intrinsic difference in quasar properties for EVQs suggests that internal processes associated with accretion are the main driver for the observed extreme long-term variability. However, despite their different properties, EVQs seem to be in the tail of a continuous distribution of quasar properties, rather than standing out as a distinct population. We speculate that EVQs are normal quasars accreting at relatively low rates, where the accretion flow is more likely to experience instabilities that drive the changes in flux by a factor of a few on multi-year timescales.

M DWARF FLARES FROM TIME-RESOLVED SLOAN DIGITAL SKY SURVEY SPECTRA

International Nuclear Information System (INIS)

Hilton, Eric J.; Hawley, Suzanne L.; Kowalski, Adam F.; West, Andrew A.

2010-01-01

We have identified 63 flares on M dwarfs from the individual component spectra in the Sloan Digital Sky Survey (SDSS) using a novel measurement of emission-line strength called the Flare Line Index. Each of the ∼38,000 M dwarfs in the SDSS low-mass star spectroscopic sample of West et al. was observed several times (usually 3-5) in exposures that were typically 9-25 minutes in duration. Our criteria allowed us to identify flares that exhibit very strong Hα and Hβ emission-line strength and/or significant variability in those lines throughout the course of the exposures. The flares we identified have characteristics consistent with flares observed by classical spectroscopic monitoring. The flare duty cycle for the objects in our sample is found to increase from 0.02% for early M dwarfs to 3% for late M dwarfs. We find that the flare duty cycle is larger in the population near the Galactic plane and that the flare stars are more spatially restricted than the magnetically active but non-flaring stars. This suggests that flare frequency may be related to stellar age (younger stars are more likely to flare) and that the flare stars are younger than the mean active population.

INTERNAL EXTINCTION IN THE SLOAN DIGITAL SKY SURVEY LATE-TYPE GALAXIES

International Nuclear Information System (INIS)

Cho, Jungyeon; Park, Changbom

2009-01-01

We study internal extinction of late-type galaxies in the Sloan Digital Sky Survey. We find that the degree of internal extinction depends on both the concentration index c and K s -band absolute magnitude M K . We give simple fitting functions for internal extinction. In particular, we present analytic formulae giving the extinction-corrected magnitudes from the observed optical parameters. For example, the extinction-corrected r-band absolute magnitude can be obtained by M r,0 =-20.77 +(-1+√(1+4Δ(M r,obs +20.77+4.93Δ)))/2Δ, where Δ = 0.236{1.35(c - 2.48) 2 - 1.14} log(a/b), c = R 90 /R 50 is the the concentration index, and a/b is the isophotal axis ratio of the 25 mag arcsec -2 isophote in the i band. The 1σ error in M r,0 is 0.21 log(a/b). Late-type galaxies with very different inclinations are found to trace almost the same sequence in the (u - r)-M r diagram when our prescriptions for extinction correction are applied. We also find that (u - r) color can be a third independent parameter that determines the degree of internal extinction.

Extreme Variability Quasars from the Sloan Digital Sky Survey and the Dark Energy Survey

Energy Technology Data Exchange (ETDEWEB)

Rumbaugh, N.; Shen, Yue; Morganson, Eric; Liu, Xin; Banerji, M.; McMahon, R. G.; Abdalla, F. B.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Capozzi, D.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Cunha, C. E.; D’Andrea, C. B.; da Costa, L. N.; DePoy, D. L.; Desai, S.; Doel, P.; Frieman, J.; García-Bellido, J.; Gruen, D.; Gruendl, R. A.; Gschwend, J.; Gutierrez, G.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuhlmann, S.; Kuropatkin, N.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Martini, P.; Menanteau, F.; Plazas, A. A.; Reil, K.; Roodman, A.; Sanchez, E.; Scarpine, V.; Schindler, R.; Schubnell, M.; Sheldon, E.; Smith, M.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Walker, A. R.; Wester, W.

2018-02-20

We perform a systematic search for long-term extreme variability quasars (EVQs) in the overlapping Sloan Digital Sky Survey (SDSS) and 3-Year Dark Energy Survey (DES) imaging, which provide light curves spanning more than 15 years. We identified ~1000 EVQs with a maximum g band magnitude change of more than 1 mag over this period, about 10% of all quasars searched. The EVQs have L_bol~10^45-10^47 erg/s and L/L_Edd~0.01-1. Accounting for selection effects, we estimate an intrinsic EVQ fraction of ~30-50% among all g<~22 quasars over a baseline of ~15 years. These EVQs are good candidates for so-called "changing-look quasars", where a spectral transition between the two types of quasars (broad-line and narrow-line) is observed between the dim and bright states. We performed detailed multi-wavelength, spectral and variability analyses for the EVQs and compared to their parent quasar sample. We found that EVQs are distinct from a control sample of quasars matched in redshift and optical luminosity: (1) their UV broad emission lines have larger equivalent widths; (2) their Eddington ratios are systematically lower; and (3) they are more variable on all timescales. The intrinsic difference in quasar properties for EVQs suggest that internal processes associated with accretion are the main driver for the observed extreme long-term variability. However, despite their different properties, EVQs seem to be in the tail of a continuous distribution of quasar properties, rather than standing out as a distinct population. We speculate that EVQs are normal quasars accreting at relatively low accretion rates, where the accretion flow is more likely to experience instabilities that drive the factor of few changes in flux on multi-year timescales.

THE MULTI-OBJECT, FIBER-FED SPECTROGRAPHS FOR THE SLOAN DIGITAL SKY SURVEY AND THE BARYON OSCILLATION SPECTROSCOPIC SURVEY

International Nuclear Information System (INIS)

Smee, Stephen A.; Barkhouser, Robert H.; Gunn, James E.; Carr, Michael A.; Lupton, Robert H.; Loomis, Craig; Uomoto, Alan; Roe, Natalie; Schlegel, David; Rockosi, Constance M.; Leger, French; Owen, Russell; Anderson, Lauren; Dawson, Kyle S.; Olmstead, Matthew D.; Brinkmann, Jon; Long, Dan; Honscheid, Klaus; Harding, Paul; Annis, James

2013-01-01

We present the design and performance of the multi-object fiber spectrographs for the Sloan Digital Sky Survey (SDSS) and their upgrade for the Baryon Oscillation Spectroscopic Survey (BOSS). Originally commissioned in Fall 1999 on the 2.5 m aperture Sloan Telescope at Apache Point Observatory, the spectrographs produced more than 1.5 million spectra for the SDSS and SDSS-II surveys, enabling a wide variety of Galactic and extra-galactic science including the first observation of baryon acoustic oscillations in 2005. The spectrographs were upgraded in 2009 and are currently in use for BOSS, the flagship survey of the third-generation SDSS-III project. BOSS will measure redshifts of 1.35 million massive galaxies to redshift 0.7 and Lyα absorption of 160,000 high redshift quasars over 10,000 deg 2 of sky, making percent level measurements of the absolute cosmic distance scale of the universe and placing tight constraints on the equation of state of dark energy. The twin multi-object fiber spectrographs utilize a simple optical layout with reflective collimators, gratings, all-refractive cameras, and state-of-the-art CCD detectors to produce hundreds of spectra simultaneously in two channels over a bandpass covering the near-ultraviolet to the near-infrared, with a resolving power R = λ/FWHM ∼ 2000. Building on proven heritage, the spectrographs were upgraded for BOSS with volume-phase holographic gratings and modern CCD detectors, improving the peak throughput by nearly a factor of two, extending the bandpass to cover 360 nm < λ < 1000 nm, and increasing the number of fibers from 640 to 1000 per exposure. In this paper we describe the original SDSS spectrograph design and the upgrades implemented for BOSS, and document the predicted and measured performances

THE MULTI-OBJECT, FIBER-FED SPECTROGRAPHS FOR THE SLOAN DIGITAL SKY SURVEY AND THE BARYON OSCILLATION SPECTROSCOPIC SURVEY

Energy Technology Data Exchange (ETDEWEB)

Smee, Stephen A.; Barkhouser, Robert H. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Gunn, James E.; Carr, Michael A.; Lupton, Robert H.; Loomis, Craig [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Uomoto, Alan [Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Roe, Natalie; Schlegel, David [Physics Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Rockosi, Constance M. [UC Observatories and Department of Astronomy and Astrophysics, University of California, Santa Cruz, 375 Interdisciplinary Sciences Building (ISB) Santa Cruz, CA 95064 (United States); Leger, French; Owen, Russell; Anderson, Lauren [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 09195 (United States); Dawson, Kyle S.; Olmstead, Matthew D. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Brinkmann, Jon; Long, Dan [Apache Point Observatory, Sunspot, NM 88349 (United States); Honscheid, Klaus [Department of Physics and Center for Cosmology and Astro-Particle Physics, Ohio State University, Columbus, OH 43210 (United States); Harding, Paul [Department of Astronomy, Case Western Reserve University, Cleveland, OH 44106 (United States); Annis, James, E-mail: smee@pha.jhu.edu [Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States); and others

2013-08-01

We present the design and performance of the multi-object fiber spectrographs for the Sloan Digital Sky Survey (SDSS) and their upgrade for the Baryon Oscillation Spectroscopic Survey (BOSS). Originally commissioned in Fall 1999 on the 2.5 m aperture Sloan Telescope at Apache Point Observatory, the spectrographs produced more than 1.5 million spectra for the SDSS and SDSS-II surveys, enabling a wide variety of Galactic and extra-galactic science including the first observation of baryon acoustic oscillations in 2005. The spectrographs were upgraded in 2009 and are currently in use for BOSS, the flagship survey of the third-generation SDSS-III project. BOSS will measure redshifts of 1.35 million massive galaxies to redshift 0.7 and Ly{alpha} absorption of 160,000 high redshift quasars over 10,000 deg{sup 2} of sky, making percent level measurements of the absolute cosmic distance scale of the universe and placing tight constraints on the equation of state of dark energy. The twin multi-object fiber spectrographs utilize a simple optical layout with reflective collimators, gratings, all-refractive cameras, and state-of-the-art CCD detectors to produce hundreds of spectra simultaneously in two channels over a bandpass covering the near-ultraviolet to the near-infrared, with a resolving power R = {lambda}/FWHM {approx} 2000. Building on proven heritage, the spectrographs were upgraded for BOSS with volume-phase holographic gratings and modern CCD detectors, improving the peak throughput by nearly a factor of two, extending the bandpass to cover 360 nm < {lambda} < 1000 nm, and increasing the number of fibers from 640 to 1000 per exposure. In this paper we describe the original SDSS spectrograph design and the upgrades implemented for BOSS, and document the predicted and measured performances.

THE MULTI-OBJECT, FIBER-FED SPECTROGRAPHS FOR THE SLOAN DIGITAL SKY SURVEY AND THE BARYON OSCILLATION SPECTROSCOPIC SURVEY

Energy Technology Data Exchange (ETDEWEB)

Smee, Stephen A.; Gunn, James E.; Uomoto, Alan; Roe, Natalie; Schlegel, David; Rockosi, Constance M.; Carr, Michael A.; Leger, French; Dawson, Kyle S.; Olmstead, Matthew D.; Brinkmann, Jon; Owen, Russell; Barkhouser, Robert H.; Honscheid, Klaus; Harding, Paul; Long, Dan; Lupton, Robert H.; Loomis, Craig; Anderson, Lauren; Annis, James; Bernardi, Mariangela; Bhardwaj, Vaishali; Bizyaev, Dmitry; Bolton, Adam S.; Brewington, Howard; Briggs, John W.; Burles, Scott; Burns, James G.; Castander, Francisco Javier; Connolly, Andrew; Davenport, James R. A.; Ebelke, Garrett; Epps, Harland; Feldman, Paul D.; Friedman, Scott D.; Frieman, Joshua; Heckman, Timothy; Hull, Charles L.; Knapp, Gillian R.; Lawrence, David M.; Loveday, Jon; Mannery, Edward J.; Malanushenko, Elena; Malanushenko, Viktor; Merrelli, Aronne James; Muna, Demitri; Newman, Peter R.; Nichol, Robert C.; Oravetz, Daniel; Pan, Kaike; Pope, Adrian C.; Ricketts, Paul G.; Shelden, Alaina; Sandford, Dale; Siegmund, Walter; Simmons, Audrey; Smith, D. Shane; Snedden, Stephanie; Schneider, Donald P.; SubbaRao, Mark; Tremonti, Christy; Waddell, Patrick; York, Donald G.

2013-07-12

We present the design and performance of the multi-object fiber spectrographs for the Sloan Digital Sky Survey (SDSS) and their upgrade for the Baryon Oscillation Spectroscopic Survey (BOSS). Originally commissioned in Fall 1999 on the 2.5-m aperture Sloan Telescope at Apache Point Observatory, the spectrographs produced more than 1.5 million spectra for the SDSS and SDSS-II surveys, enabling a wide variety of Galactic and extra-galactic science including the first observation of baryon acoustic oscillations in 2005. The spectrographs were upgraded in 2009 and are currently in use for BOSS, the flagship survey of the third-generation SDSS-III project. BOSS will measure redshifts of 1.35 million massive galaxies to redshift 0.7 and Lyman-alpha absorption of 160,000 high redshift quasars over 10,000 square degrees of sky, making percent level measurements of the absolute cosmic distance scale of the Universe and placing tight constraints on the equation of state of dark energy. The twin multi-object fiber spectrographs utilize a simple optical layout with reflective collimators, gratings, all-refractive cameras, and state-of-the-art CCD detectors to produce hundreds of spectra simultaneously in two channels over a bandpass covering the near ultraviolet to the near infrared, with a resolving power R = \\lambda/FWHM ~ 2000. Building on proven heritage, the spectrographs were upgraded for BOSS with volume-phase holographic gratings and modern CCD detectors, improving the peak throughput by nearly a factor of two, extending the bandpass to cover 360 < \\lambda < 1000 nm, and increasing the number of fibers from 640 to 1000 per exposure. In this paper we describe the original SDSS spectrograph design and the upgrades implemented for BOSS, and document the predicted and measured performances.

THE FIFTH DATA RELEASE SLOAN DIGITAL SKY SURVEY/XMM-NEWTON QUASAR SURVEY

International Nuclear Information System (INIS)

Young, M.; Elvis, M.; Risaliti, G.

2009-01-01

We present a catalog of 792 Fifth Data Release Sloan Digital Sky Survey quasars with optical spectra that have been observed serendipitously in the X-rays with the XMM-Newton. These quasars cover a redshift range of z = 0.11-5.41 and a magnitude range of i = 15.3-20.7. Substantial numbers of radio-loud (70) and broad absorption line (51) quasars exist within this sample. Significant X-ray detections at ≥2σ account for 87% of the sample (685 quasars), and 473 quasars are detected at ≥6σ, sufficient to allow X-ray spectral fits. For detected sources, ∼60% have X-ray fluxes between F 2-10keV = (1-10) x10 -14 erg cm -2 s -1 . We fit a single power law, a fixed power law with intrinsic absorption left free to vary, and an absorbed power-law model to all quasars with X-ray signal-to-noise ratio ≥ 6, resulting in a weighted mean photon index Γ = 1.91 ± 0.08, with an intrinsic dispersion σ Γ = 0.38. For the 55 sources (11.6%) that prefer intrinsic absorption, we find a weighted mean N H = 1.5 ± 0.3 x 10 21 cm -2 . We find that Γ correlates significantly with optical color, Δ(g - i), the optical-to-X-ray spectral index (α ox ), and the X-ray luminosity. While the first two correlations can be explained as artifacts of undetected intrinsic absorption, the correlation between Γ and X-ray luminosity appears to be a real physical correlation, indicating a pivot in the X-ray slope.

A SEARCH FOR DISK-GALAXY LENSES IN THE SLOAN DIGITAL SKY SURVEY

International Nuclear Information System (INIS)

Feron, Chloe; Hjorth, Jens; Samsing, Johan; McKean, John P.

2009-01-01

We present the first automated spectroscopic search for disk-galaxy lenses, using the Sloan Digital Sky Survey (SDSS) database. We follow up eight gravitational lens candidates, selected among a sample of ∼40,000 candidate massive disk galaxies, using a combination of ground-based imaging and long-slit spectroscopy. We confirm two gravitational lens systems: one probable disk galaxy and one probable S0 galaxy. The remaining systems are four promising disk-galaxy lens candidates, as well as two probable gravitational lenses whose lens galaxy might be an S0 galaxy. The redshifts of the lenses are z lens ∼ 0.1. The redshift range of the background sources is z source ∼ 0.3-0.7. The systems presented here are (confirmed or candidate) galaxy-galaxy lensing systems, that is, systems where the multiple images are faint and extended, allowing an accurate determination of the lens galaxy mass and light distributions without contamination from the background galaxy. Moreover, the low redshift of the (confirmed or candidates) lens galaxies is favorable for measuring rotation points to complement the lensing study. We estimate the rest-frame total mass-to-light ratio within the Einstein radius for the two confirmed lenses: we find M tot /L I = 5.4 ± 1.5 within 3.9 ± 0.9 kpc for SDSS J081230.30+543650.9 and M tot /L I = 1.5 ± 0.9 within 1.4 ± 0.8 kpc for SDSS J145543.55+530441.2 (all in solar units). Hubble Space Telescope or adaptive optics imaging is needed to further study the systems.

The Sloan Digital Sky Survey Quasar Catalog. 4. Fifth Data Release

Energy Technology Data Exchange (ETDEWEB)

Schneider, Donald P.; Hall, Patrick B.; Richards, Gordon T.; Strauss, Michael A.; Vanden Berk, Daniel E.; Anderson, Scott F.; Brandt, W.N.; Fan, Xiao-Hui; Jester,; Gray, Jim; Gunn, James E.; /Penn State U., Astron. Astrophys. /York U., Canada /Johns Hopkins U. /Princeton U. Observ. /Washington U., Seattle, Astron. Dept. /Arizona

2007-04-01

We present the fourth edition of the Sloan Digital Sky Survey (SDSS) Quasar Catalog. The catalog contains 77,429 objects; this is an increase of over 30,000 entries since the previous edition. The catalog consists of the objects in the SDSS Fifth Data Release that have luminosities larger than M{sub i} = -22.0 (in a cosmology with H{sub 0} = 70 km s{sup -1} Mpc{sup -1}, {Omega}{sub M} = 0.3, and {Omega}{sub {Lambda}} = 0.7), have at least one emission line with FWHM larger than 1000 km s{sup -1} or have interesting/complex absorption features, are fainter than i {approx} 15.0, and have highly reliable redshifts. The area covered by the catalog is {approx} 5740 deg{sup 2}. The quasar redshifts range from 0.08 to 5.41, with a median value of 1.48; the catalog includes 891 quasars at redshifts greater than four, of which 36 are at redshifts greater than five. Approximately half of the catalog quasars have i < 19; nearly all have i < 21. For each object the catalog presents positions accurate to better than 0.2-minutes rms per coordinate, five-band (ugriz) CCD-based photometry with typical accuracy of 0.03 mag, and information on the morphology and selection method. The catalog also contains basic radio, near-infrared, and X-ray emission properties of the quasars, when available, from other large-area surveys. The calibrated digital spectra cover the wavelength region 3800-9200 {angstrom} at a spectral resolution of {approx_equal} 2000; the spectra can be retrieved from the public database using the information provided in the catalog. The average SDSS colors of quasars as a function of redshift, derived from the catalog entries, are presented in tabular form. Approximately 96% of the objects in the catalog were discovered by the SDSS.

The Missing Link: Early Methane ("T") Dwarfs in the Sloan Digital Sky Survey.

Science.gov (United States)

Leggett; Geballe; Fan; Schneider; Gunn; Lupton; Knapp; Strauss; McDaniel; Golimowski; Henry; Peng; Tsvetanov; Uomoto; Zheng; Hill; Ramsey; Anderson; Annis; Bahcall; Brinkmann; Chen; Csabai; Fukugita; Hennessy; Hindsley; Ivezic; Lamb; Munn; Pier; Schlegel; Smith; Stoughton; Thakar; York

2000-06-10

We report the discovery of three cool brown dwarfs that fall in the effective temperature gap between the latest L dwarfs currently known, with no methane absorption bands in the 1-2.5 µm range, and the previously known methane (T) dwarfs, whose spectra are dominated by methane and water. The newly discovered objects were detected as very red objects in the Sloan Digital Sky Survey imaging data and have JHK colors between the red L dwarfs and the blue Gl 229B-like T dwarfs. They show both CO and CH(4) absorption in their near-infrared spectra in addition to H(2)O, with weaker CH(4) absorption features in the H and K bands than those in all other methane dwarfs reported to date. Due to the presence of CH(4) in these bands, we propose that these objects are early T dwarfs. The three form part of the brown dwarf spectral sequence and fill in the large gap in the overall spectral sequence from the hottest main-sequence stars to the coolest methane dwarfs currently known.

Sloan foundation nuclear education program

International Nuclear Information System (INIS)

Kursunoglu, B.N.

1992-01-01

The Alfred P. Sloan Foundation realized the time had come for a real and significant contribution to the enlightenment of university students concerning nuclear matters. The Sloan Foundation chose to educate the youth of four-year colleges and universities with a curriculum established with the resource information sieved from three workshops for professors in these institutions. The three workshops were organized by groups at Harvard-MIT (two-week Summer Program on Nuclear Weapons and Arms Control), the University of California, San Diego (two-week Summer Seminar on Global Security and Arms Control), and the University of Miami (one-week Winter Workshop on Enlightenment: The Best Security in a Nuclear-Armed World). In this report the author focuses on a unified presentation of the basic facts, aims, and results of the Sloan Foundation Nuclear Education Program based on three workshops directed by Jack Ruina (MIT), Herbert York (USCD), and Behram Kursunoglu (UM) and offered from 1983-1990

The Sloan Digital Sky Survey Reverberation Mapping Project: Composite Lags at z ≤ 1

Science.gov (United States)

Li, Jennifer; Shen, Yue; Horne, Keith; Brandt, W. N.; Greene, Jenny E.; Grier, C. J.; Ho, Luis C.; Kochanek, Chris; Schneider, Donald P.; Trump, Jonathan R.; Dawson, Kyle S.; Pan, Kaike; Bizyaev, Dmitry; Oravetz, Daniel; Simmons, Audrey; Malanushenko, Elena

2017-09-01

We present composite broad-line region (BLR) reverberation mapping lag measurements for Hα, Hβ, He II λ4686, and Mg II for a sample of 144, z ≲ 1 quasars from the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project. Using only the 32-epoch spectroscopic light curves in the first six-month season of SDSS-RM observations, we compile correlation function measurements for individual objects and then coadd them to allow the measurement of the average lags for our sample at mean redshifts of 0.4 (for Hα) and ˜0.65 (for the other lines). At similar quasar luminosities and redshifts, the sample-averaged lag decreases in the order of Mg II, Hα, Hβ, and He II. This decrease in lags is accompanied by an increase in the mean line width of the four lines, and is roughly consistent with the virialized motion for BLR gas in photoionization equilibrium. These are among the first RM measurements of stratified BLR structure at z > 0.3. Dividing our sample by luminosity, Hα shows clear evidence of increasing lags with luminosity, consistent with the expectation from the measured BLR size-luminosity relation based on Hβ. The other three lines do not show a clear luminosity trend in their average lags due to the limited dynamic range of luminosity probed and the poor average correlation signals in the divided samples, a situation that will be improved with the incorporation of additional photometric and spectroscopic data from SDSS-RM. We discuss the utility and caveats of composite lag measurements for large statistical quasar samples with reverberation mapping data.

The Sloan Digital Sky Survey Reverberation Mapping Project: Composite Lags at z ≤ 1

Energy Technology Data Exchange (ETDEWEB)

Li, Jennifer; Shen, Yue [Department of Astronomy, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Horne, Keith [SUPA Physics/Astronomy, Univ. of St. Andrews, St. Andrews KY16 9SS (United Kingdom); Brandt, W. N.; Grier, C. J.; Schneider, Donald P. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA, 16802 (United States); Greene, Jenny E. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Ho, Luis C. [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China); Kochanek, Chris [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Trump, Jonathan R. [Department of Physics, University of Connecticut, 2152 Hillside Road, Unit 3046, Storrs, CT 06269 (United States); Dawson, Kyle S. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Pan, Kaike; Bizyaev, Dmitry; Oravetz, Daniel; Simmons, Audrey; Malanushenko, Elena [Apache Point Observatory and New Mexico State University, P.O. Box 59, Sunspot, NM, 88349-0059 (United States)

2017-09-01

We present composite broad-line region (BLR) reverberation mapping lag measurements for H α , H β , He ii λ 4686, and Mg ii for a sample of 144, z ≲ 1 quasars from the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project. Using only the 32-epoch spectroscopic light curves in the first six-month season of SDSS-RM observations, we compile correlation function measurements for individual objects and then coadd them to allow the measurement of the average lags for our sample at mean redshifts of 0.4 (for H α ) and ∼0.65 (for the other lines). At similar quasar luminosities and redshifts, the sample-averaged lag decreases in the order of Mg ii, H α , H β , and He ii. This decrease in lags is accompanied by an increase in the mean line width of the four lines, and is roughly consistent with the virialized motion for BLR gas in photoionization equilibrium. These are among the first RM measurements of stratified BLR structure at z > 0.3. Dividing our sample by luminosity, H α shows clear evidence of increasing lags with luminosity, consistent with the expectation from the measured BLR size–luminosity relation based on H β . The other three lines do not show a clear luminosity trend in their average lags due to the limited dynamic range of luminosity probed and the poor average correlation signals in the divided samples, a situation that will be improved with the incorporation of additional photometric and spectroscopic data from SDSS-RM. We discuss the utility and caveats of composite lag measurements for large statistical quasar samples with reverberation mapping data.

The Sloan Digital Sky Survey Reverberation Mapping Project: Composite Lags at z ≤ 1

International Nuclear Information System (INIS)

Li, Jennifer; Shen, Yue; Horne, Keith; Brandt, W. N.; Grier, C. J.; Schneider, Donald P.; Greene, Jenny E.; Ho, Luis C.; Kochanek, Chris; Trump, Jonathan R.; Dawson, Kyle S.; Pan, Kaike; Bizyaev, Dmitry; Oravetz, Daniel; Simmons, Audrey; Malanushenko, Elena

2017-01-01

We present composite broad-line region (BLR) reverberation mapping lag measurements for H α , H β , He ii λ 4686, and Mg ii for a sample of 144, z ≲ 1 quasars from the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project. Using only the 32-epoch spectroscopic light curves in the first six-month season of SDSS-RM observations, we compile correlation function measurements for individual objects and then coadd them to allow the measurement of the average lags for our sample at mean redshifts of 0.4 (for H α ) and ∼0.65 (for the other lines). At similar quasar luminosities and redshifts, the sample-averaged lag decreases in the order of Mg ii, H α , H β , and He ii. This decrease in lags is accompanied by an increase in the mean line width of the four lines, and is roughly consistent with the virialized motion for BLR gas in photoionization equilibrium. These are among the first RM measurements of stratified BLR structure at z > 0.3. Dividing our sample by luminosity, H α shows clear evidence of increasing lags with luminosity, consistent with the expectation from the measured BLR size–luminosity relation based on H β . The other three lines do not show a clear luminosity trend in their average lags due to the limited dynamic range of luminosity probed and the poor average correlation signals in the divided samples, a situation that will be improved with the incorporation of additional photometric and spectroscopic data from SDSS-RM. We discuss the utility and caveats of composite lag measurements for large statistical quasar samples with reverberation mapping data.

Sloan Digital Sky Survey photometric telescope automation and observing software

International Nuclear Information System (INIS)

Eric H. Neilsen, Jr.; email = neilsen@fnal.gov

2002-01-01

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

THE PHYSICAL ORIGINS OF THE MORPHOLOGY-DENSITY RELATION: EVIDENCE FOR GAS STRIPPING FROM THE SLOAN DIGITAL SKY SURVEY

International Nuclear Information System (INIS)

Van der Wel, Arjen; Bell, Eric F.; Skibba, Ramin A.; Rix, Hans-Walter; Holden, Bradford P.

2010-01-01

We provide a physical interpretation and explanation of the morphology-density relation for galaxies, drawing on stellar masses, star formation rates, axis ratios, and group halo masses from the Sloan Digital Sky Survey. We first re-cast the classical morphology-density relation in more quantitative terms, using low star formation rate (quiescence) as a proxy for early-type morphology and dark matter halo mass from a group catalog as a proxy for environmental density: for galaxies of a given stellar mass the quiescent fraction is found to increase with increasing dark matter halo mass. Our novel result is that-at a given stellar mass-quiescent galaxies are significantly flatter in dense environments, implying a higher fraction of disk galaxies. Supposing that the denser environments differ simply by a higher incidence of quiescent disk galaxies that are structurally similar to star-forming disk galaxies of similar mass, explains simultaneously and quantitatively these quiescence-environment and shape-environment relations. Our findings add considerable weight to the slow removal of gas as the main physical driver of the morphology-density relation, at the expense of other explanations.

A NEAR-INFRARED SPECTROSCOPIC SURVEY OF COOL WHITE DWARFS IN THE SLOAN DIGITAL SKY SURVEY

International Nuclear Information System (INIS)

Kilic, Mukremin; Kowalski, Piotr M.; Von Hippel, Ted

2009-01-01

We present near-infrared photometric observations of 15 and spectroscopic observations of 38 cool white dwarfs (WDs). This is the largest near-infrared spectroscopic survey of cool WDs to date. Combining the Sloan Digital Sky Survey photometry and our near-infrared data, we perform a detailed model atmosphere analysis. The spectral energy distributions of our objects are explained fairly well by model atmospheres with temperatures ranging from 6300 K down to 4200 K. Two WDs show significant absorption in the infrared, and are best explained with mixed H/He atmosphere models. Based on the up-to-date model atmosphere calculations by Kowalski and Saumon, we find that the majority of the stars in our sample have hydrogen-rich atmospheres. We do not find any pure helium atmosphere WDs below 5000 K, and we find a trend of increasing hydrogen to helium ratio with decreasing temperature. These findings present an important challenge to understanding the spectral evolution of WDs.

Two-dimensional Topology of the Sloan Digital Sky Survey

Science.gov (United States)

Hoyle, Fiona; Vogeley, Michael S.; Gott, J. Richard, III; Blanton, Michael; Tegmark, Max; Weinberg, David H.; Bahcall, N.; Brinkmann, J.; York, D.

2002-12-01

We present the topology of a volume-limited sample of 11,884 galaxies, selected from an apparent magnitude limited sample of over 100,000 galaxies observed as part of the Sloan Digital Sky Survey (SDSS). The data currently cover three main regions on the sky: one in the Galactic north and one in the south, both at zero degrees declination, and one area in the north at higher declination. Each of these areas covers a wide range of survey longitude but a narrow range of survey latitude, allowing the two-dimensional genus to be measured. The genus curves of the SDSS subsamples are similar, after appropriately normalizing these measurements for the different areas. We sum the genus curves from the three areas to obtain the total genus curve of the SDSS. The total curve has a shape similar to the genus curve derived from mock catalogs drawn from the Hubble volume ΛCDM simulation and is similar to that of a Gaussian random field. Likewise, comparison with the genus of the Two-Degree Field Galaxy Redshift Survey, after normalization for the difference in area, reveals remarkable similarity in the topology of these samples. We test for the effects of galaxy-type segregation by splitting the SDSS data into thirds, based on the u*-r* colors of the galaxies, and measure the genus of the reddest and bluest subsamples. This red/blue split in u*-r* is essentially a split by morphology, as explained by Strateva and coworkers. We find that the genus curve for the reddest galaxies exhibits a ``meatball'' shift of the topology-reflecting the concentration of red galaxies in high-density regions-compared to the bluest galaxies and the full sample, in agreement with predictions from simulations.

THE PITTSBURGH SLOAN DIGITAL SKY SURVEY Mg II QUASAR ABSORPTION-LINE SURVEY CATALOG

International Nuclear Information System (INIS)

Quider, Anna M.; Nestor, Daniel B.; Turnshek, David A.; Rao, Sandhya M.; Weyant, Anja N.; Monier, Eric M.; Busche, Joseph R.

2011-01-01

We present a catalog of intervening Mg II quasar absorption-line systems in the redshift interval 0.36 ≤ z ≤ 2.28. The catalog was built from Sloan Digital Sky Survey Data Release Four (SDSS DR4) quasar spectra. Currently, the catalog contains ∼17, 000 measured Mg II doublets. We also present data on the ∼44, 600 quasar spectra which were searched to construct the catalog, including redshift and magnitude information, continuum-normalized spectra, and corresponding arrays of redshift-dependent minimum rest equivalent widths detectable at our confidence threshold. The catalog is available online. A careful second search of 500 random spectra indicated that, for every 100 spectra searched, approximately one significant Mg II system was accidentally rejected. Current plans to expand the catalog beyond DR4 quasars are discussed. Many Mg II absorbers are known to be associated with galaxies. Therefore, the combination of large size and well understood statistics makes this catalog ideal for precision studies of the low-ionization and neutral gas regions associated with galaxies at low to moderate redshift. An analysis of the statistics of Mg II absorbers using this catalog will be presented in a subsequent paper.

THE BLACK HOLE MASS-GALAXY LUMINOSITY RELATIONSHIP FOR SLOAN DIGITAL SKY SURVEY QUASARS

International Nuclear Information System (INIS)

Salviander, S.; Shields, G. A.; Bonning, E. W.

2015-01-01

We investigate the relationship between the mass of the central supermassive black hole, M BH , and the host galaxy luminosity, L gal , in a sample of quasars from the Sloan Digital Sky Survey Data Release 7. We use composite quasar spectra binned by black hole mass and redshift to assess galaxy features that would otherwise be overwhelmed by noise in individual spectra. The black hole mass is calculated using the photoionization method, and the host galaxy luminosity is inferred from the depth of the Ca II H+K features in the composite spectra. We evaluate the evolution in the M BH -L gal relationship by examining the redshift dependence of Δ log M BH , the offset in M BH from the local M BH -L gal relationship. There is little systematic trend in Δ log M BH out to z = 0.8. Using the width of the [O III] emission line as a proxy for the stellar velocity dispersion, σ * , we find agreement of our derived host luminosities with the locally observed Faber-Jackson relation. This supports the utility of the width of the [O III] line as a proxy for σ * in statistical studies

H I-SELECTED GALAXIES IN THE SLOAN DIGITAL SKY SURVEY. I. OPTICAL DATA

International Nuclear Information System (INIS)

West, Andrew A.; Garcia-Appadoo, Diego A.; Dalcanton, Julianne J.; Ivezic, Zeljko; Bentz, Misty C.; Disney, Mike J.; Rockosi, Constance M.; Brinkmann, J.

2010-01-01

We present the optical data for 195 H I-selected galaxies that fall within both the Sloan Digital Sky Survey (SDSS) and the Parkes Equatorial Survey (ES). The photometric quantities have been independently recomputed for our sample using a new photometric pipeline optimized for large galaxies, thus correcting for SDSS's limited reliability for automatic photometry of angularly large or low surface brightness (LSB) galaxies. We outline the magnitude of the uncertainty in the SDSS catalog-level photometry and derive a quantitative method for correcting the over-sky subtraction in the SDSS photometric pipeline. The main thrust of this paper is to present the ES/SDSS sample and discuss the methods behind the improved photometry, which will be used in future scientific analysis. We present the overall optical properties of the sample and briefly compare to a volume-limited, optically selected sample. Compared to the optically selected SDSS sample (in the similar volume), H I-selected galaxies are bluer and more luminous (fewer dwarf ellipticals and more star formation). However, compared to typical SDSS galaxy studies, which have their own selection effect, our sample is bluer, fainter, and less massive.

A Search for Nontoroidal Topological Lensing in the Sloan Digital Sky Survey Quasar Catalog

Science.gov (United States)

Fujii, Hirokazu; Yoshii, Yuzuru

2013-08-01

Flat space models with multiply connected topology, which have compact dimensions, are tested against the distribution of high-redshift (z >= 4) quasars of the Sloan Digital Sky Survey (SDSS). When the compact dimensions are smaller in size than the observed universe, topological lensing occurs, in which multiple images of single objects (ghost images) are observed. We improve on the recently introduced method to identify ghost images by means of four-point statistics. Our method is valid for any of the 17 multiply connected flat models, including nontoroidal ones that are compacted by screw motions or glide reflection. Applying the method to the data revealed one possible case of topological lensing caused by sixth-turn screw motion, however, it is consistent with the simply connected model by this test alone. Moreover, simulations suggest that we cannot exclude the other space models despite the absence of their signatures. This uncertainty mainly originates from the patchy coverage of SDSS in the south Galactic cap, and this situation will be improved by future wide-field spectroscopic surveys.

A SEARCH FOR NONTOROIDAL TOPOLOGICAL LENSING IN THE SLOAN DIGITAL SKY SURVEY QUASAR CATALOG

International Nuclear Information System (INIS)

Fujii, Hirokazu; Yoshii, Yuzuru

2013-01-01

Flat space models with multiply connected topology, which have compact dimensions, are tested against the distribution of high-redshift (z ≥ 4) quasars of the Sloan Digital Sky Survey (SDSS). When the compact dimensions are smaller in size than the observed universe, topological lensing occurs, in which multiple images of single objects (ghost images) are observed. We improve on the recently introduced method to identify ghost images by means of four-point statistics. Our method is valid for any of the 17 multiply connected flat models, including nontoroidal ones that are compacted by screw motions or glide reflection. Applying the method to the data revealed one possible case of topological lensing caused by sixth-turn screw motion, however, it is consistent with the simply connected model by this test alone. Moreover, simulations suggest that we cannot exclude the other space models despite the absence of their signatures. This uncertainty mainly originates from the patchy coverage of SDSS in the south Galactic cap, and this situation will be improved by future wide-field spectroscopic surveys

The Sloan Digital Sky Survey Quasar Catalog V. Seventh Data Release

Energy Technology Data Exchange (ETDEWEB)

Schneider, Donald P.; /Penn State U.; Richards, Gordon T.; /Drexel U.; Hall, Patrick B.; /York U., Canada; Strauss, Michael A.; /Princeton U. Observ.; Anderson, Scott F.; /Washington U., Seattle, Astron. Dept.; Boroson, Todd A.; /Kitt Peak Observ.; Ross, Nicholas P.; /Penn State U.; Shen, Yue; /Princeton U. Observ.; Brandt, W.N.; /Penn State U.; Fan, Xiaohui; /Arizona U., Astron. Dept. - Steward Observ.; Inada, Naohisa; /Wako, RIKEN /Southampton U. /Heidelberg, Max Planck Inst. Astron.

2010-04-01

We present the fifth edition of the Sloan Digital Sky Survey (SDSS) Quasar Catalog, which is based upon the SDSS Seventh Data Release. The catalog, which contains 105,783 spectroscopically confirmed quasars, represents the conclusion of the SDSS-I and SDSS-II quasar survey. The catalog consists of the SDSS objects that have luminosities larger than M{sub i} = -22.0 (in a cosmology with H{sub 0} = 70 km s{sup -1} Mpc{sup -1}, {Omega}{sub M} = 0.3, and {Omega}{sub {Lambda}} = 0.7), have at least one emission line with FWHM larger than 1000 km s{sup -1} or have interesting/complex absorption features, are fainter than i {approx} 15.0, and have highly reliable redshifts. The catalog covers an area of {approx} 9380 deg{sup 2}. The quasar redshifts range from 0.065 to 5.46, with a median value of 1.49; the catalog includes 1248 quasars at redshifts greater than 4, of which 56 are at redshifts greater than 5. The catalog contains 9210 quasars with i < 18; slightly over half of the entries have i < 19. For each object the catalog presents positions accurate to better than 0.1-inch rms per coordinate, five-band (ugriz) CCD-based photometry with typical accuracy of 0.03 mag, and information on the morphology and selection method. The catalog also contains radio, near-infrared, and X-ray emission properties of the quasars, when available, from other large-area surveys. The calibrated digital spectra cover the wavelength region 3800-9200 {angstrom} at a spectral resolution of {approx_equal} 2000; the spectra can be retrieved from the SDSS public database using the information provided in the catalog. Over 96% of the objects in the catalog were discovered by the SDSS. We also include a supplemental list of an additional 207 quasars with SDSS spectra whose archive photometric information is incomplete.

THE SLOAN DIGITAL SKY SURVEY CO-ADD: CROSS-CORRELATION WEAK LENSING AND TOMOGRAPHY OF GALAXY CLUSTERS

International Nuclear Information System (INIS)

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

2012-01-01

The shapes of distant galaxies are sheared by intervening galaxy clusters. We examine this effect in Stripe 82, a 275 deg 2 region observed multiple times in the Sloan Digital Sky Survey (SDSS) and co-added to achieve greater depth. We obtain a mass-richness calibration that is similar to other SDSS analyses, demonstrating that the co-addition process did not adversely affect the lensing signal. We also propose a new parameterization of the effect of tomography on the cluster lensing signal which does not require binning in redshift, and we show that using this parameterization we can detect tomography for stacked clusters at varying redshifts. Finally, due to the sensitivity of the tomographic detection to accurately marginalize over the effect of the cluster mass, we show that tomography at low redshift (where dependence on exact cosmological models is weak) can be used to constrain mass profiles in clusters.

Optical spectroscopic observations of blazars and γ-ray blazar candidates in the sloan digital sky survey data release nine

Energy Technology Data Exchange (ETDEWEB)

Massaro, F.; Masetti, N.; D' Abrusco, R.; Paggi, A.; Funk, S.

2014-09-09

We present an analysis of the optical spectra available in the Sloan Digital Sky Survey data release nine (SDSS DR9) for the blazars listed in the ROMA-BZCAT and for the γ-ray blazar candidates selected according to their IR colors. First, we adopt a statistical approach based on Monte Carlo simulations to find the optical counterparts of the blazars listed in the ROMA-BZCAT catalog. Then, we crossmatched the SDSS spectroscopic catalog with our selected samples of blazars and γ-ray blazar candidates, searching for those with optical spectra available to classify our blazar-like sources and, whenever possible, to confirm their redshifts. Our main objectives are to determine the classification of uncertain blazars listed in the ROMA-BZCAT and to discover new gamma-ray blazars. For the ROMA-BZCAT sources, we investigated a sample of 84 blazars, confirming the classification for 20 of them and obtaining 18 new redshift estimates. For the γ-ray blazars, indicated as potential counterparts of unassociated Fermi sources or with uncertain nature, we established the blazar-like nature of 8 out of the 27 sources analyzed and confirmed 14 classifications.

First Year Digital Marketing Plan : Case: Arctos

OpenAIRE

Järvelin, Reetta

2016-01-01

Digital marketing is becoming increasingly important, as communication through digital chan-nels develops and some aspects of traditional marketing become irrelevant. Digital marketing focuses on current and relevant methods of reaching audiences, making it a valuable marketing asset for businesses. This thesis is a study into the field of digital marketing, including common tools and best practices. The thesis is a project-based thesis, which aims to create a complete digital marketing p...

High-Redshift Quasars Found in Sloan Digital Sky Survey Commissioning Data. II. The Spring Equatorial Stripe

International Nuclear Information System (INIS)

Fan, Xiaohui; Strauss, Michael A.; Schneider, Donald P.; Gunn, James E.; Lupton, Robert H.; Anderson, Scott F.; Voges, Wolfgang; Margon, Bruce; Annis, James; Bahcall, Neta A.

2000-01-01

This is the second paper in a series aimed at finding high-redshift quasars from five-color (u ' g ' r ' i ' z ' ) imaging data taken along the Celestial Equator by the Sloan Digital Sky Survey (SDSS) during its commissioning phase. In this paper, we present 22 high-redshift quasars (z>3.6) discovered from ∼250 deg2 of data in the spring Equatorial Stripe, plus photometry for two previously known high-redshift quasars in the same region of the sky. Our success rate in identifying high-redshift quasars is 68%. Five of the newly discovered quasars have redshifts higher than 4.6 (z=4.62, 4.69, 4.70, 4.92, and 5.03). All the quasars have i * B 0 =0.5). Several of the quasars show unusual emission and absorption features in their spectra, including an object at z=4.62 without detectable emission lines, and a broad absorption line (BAL) quasar at z=4.92. (c) (c) 2000. The American Astronomical Society

THE SLOAN DIGITAL SKY SURVEY QUASAR LENS SEARCH. V. FINAL CATALOG FROM THE SEVENTH DATA RELEASE

International Nuclear Information System (INIS)

Inada, Naohisa; Oguri, Masamune; Kayo, Issha; Fukugita, Masataka; Shin, Min-Su; Strauss, Michael A.; Bahcall, Neta A.; Morokuma, Tomoki; Rusu, Cristian E.; Kochanek, Christopher S.; Richards, Gordon T.; Schneider, Donald P.; York, Donald G.; Frieman, Joshua A.; Hall, Patrick B.; White, Richard L.

2012-01-01

We present the final statistical sample of lensed quasars from the Sloan Digital Sky Survey (SDSS) Quasar Lens Search (SQLS). The well-defined statistical lens sample consists of 26 lensed quasars brighter than i = 19.1 and in the redshift range of 0.6 < z < 2.2 selected from 50,826 spectroscopically confirmed quasars in the SDSS Data Release 7 (DR7), where we restrict the image separation range to 1'' < θ < 20'' and the i-band magnitude differences in two images to be smaller than 1.25 mag. The SDSS DR7 quasar catalog also contains 36 additional lenses identified with various techniques. In addition to these lensed quasars, we have identified 81 pairs of quasars from follow-up spectroscopy, 26 of which are physically associated binary quasars. The statistical lens sample covers a wide range of image separations, redshifts, and magnitudes, and therefore is suitable for systematic studies of cosmological parameters and surveys of the structure and evolution of galaxies and quasars.

First-Year Spectroscopy for the SDSS-II Supernova Survey

Energy Technology Data Exchange (ETDEWEB)

Zheng, Chen; Romani, Roger W.; Sako, Masao; Marriner, John; Bassett, Bruce; Becker, Andrew; Choi, Changsu; Cinabro, David; DeJongh, Fritz; Depoy, Darren L.; Dilday, Ben; Doi, Mamoru; Frieman, Joshua A.; Garnavich, Peter M.; Hogan, Craig J.; Holtzman, Jon; Im, Myungshin; Jha, Saurabh; Kessler, Richard; Konishi, Kohki; Lampeitl, Hubert

2008-03-25

This paper presents spectroscopy of supernovae discovered in the first season of the Sloan Digital Sky Survey-II Supernova Survey. This program searches for and measures multi-band light curves of supernovae in the redshift range z = 0.05-0.4, complementing existing surveys at lower and higher redshifts. Our goal is to better characterize the supernova population, with a particular focus on SNe Ia, improving their utility as cosmological distance indicators and as probes of dark energy. Our supernova spectroscopy program features rapid-response observations using telescopes of a range of apertures, and provides confirmation of the supernova and host-galaxy types as well as precise redshifts. We describe here the target identification and prioritization, data reduction, redshift measurement, and classification of 129 SNe Ia, 16 spectroscopically probable SNe Ia, 7 SNe Ib/c, and 11 SNe II from the first season. We also describe our efforts to measure and remove the substantial host galaxy contamination existing in the majority of our SN spectra.

The Discovery of a Luminous Z=5.80 Quasar from the Sloan Digital Sky Survey

Science.gov (United States)

Fan, Xiaohui; White, Richard L.; Davis, Marc; Becker, Robert H.; Strauss, Michael A.; Haiman, Zoltan; Schneider, Donald P.; Gregg, Michael D.; Gunn, James E.; Knapp, G. R.; Lupton, Robert H.; Anderson, John E., Jr.; Anderson, Scott F.; Annis, James; Bahcall, Neta A.; Boroski, William N.; Brunner, Robert J.; Chen, Bing; Connolly, Andrew J.; Csabai, István; Doi, Mamoru; Fukugita, Masataka; Hennessy, G. S.; Hindsley, Robert B.; Ichikawa, Takashi; Ivezić, Željko; Loveday, Jon; Meiksin, Avery; McKay, Timothy A.; Munn, Jeffrey A.; Newberg, Heidi Jo; Nichol, Robert; Okamura, Sadanori; Pier, Jeffrey R.; Sekiguchi, Maki; Shimasaku, Kazuhiro; Stoughton, Chris; Szalay, Alexander S.; Szokoly, Gyula P.; Thakar, Aniruddha R.; Vogeley, Michael S.; York, Donald G.

2000-09-01

We present observations of SDSSp J104433.04-012502.2, a luminous quasar at z=5.80 discovered from Sloan Digital Sky Survey (SDSS) multicolor imaging data. This object was selected as an i'-band dropout object, with i*=21.8+/-0.2 and z*=19.2+/-0.1. It has an absolute magnitude M1450=-27.2 (H0=50 km s-1 Mpc-1, q0=0.5). The spectrum shows a strong and broad Lyα emission line, strong Lyα forest absorption lines with a mean continuum decrement DA=0.91 and a Lyman limit system at z=5.72. The spectrum also shows strong O I and Si IV emission lines similar to those of quasars at zuniverse is already highly ionized at z~5.8. Using a high-resolution spectrum in the Lyα forest region, we place a conservative upper limit on the optical depth because of the Gunn-Peterson effect of τUniversity of California, and NASA, and was made possible by the generous financial support of the W. M. Keck Foundation.

Red Misfits in the Sloan Digital Sky Survey: properties of star-forming red galaxies

Science.gov (United States)

Evans, Fraser A.; Parker, Laura C.; Roberts, Ian D.

2018-06-01

We study Red Misfits, a population of red, star-forming galaxies in the local Universe. We classify galaxies based on inclination-corrected optical colours and specific star formation rates derived from the Sloan Digital Sky Survey Data Release 7. Although the majority of blue galaxies are star-forming and most red galaxies exhibit little to no ongoing star formation, a small but significant population of galaxies (˜11 per cent at all stellar masses) are classified as red in colour yet actively star-forming. We explore a number of properties of these galaxies and demonstrate that Red Misfits are not simply dusty or highly inclined blue cloud galaxies or quiescent red galaxies with poorly constrained star formation. The proportion of Red Misfits is nearly independent of environment, and this population exhibits both intermediate morphologies and an enhanced likelihood of hosting an active galactic nucleus. We conclude that Red Misfits are a transition population, gradually quenching on their way to the red sequence and this quenching is dominated by internal processes rather than environmentally driven processes. We discuss the connection between Red Misfits and other transition galaxy populations, namely S0s, red spirals, and green valley galaxies.

THE SLOAN DIGITAL SKY SURVEY DATA RELEASE 7 SPECTROSCOPIC M DWARF CATALOG. I. DATA

International Nuclear Information System (INIS)

West, Andrew A.; Morgan, Dylan P.; Andersen, Jan Marie; Covey, Kevin R.; Schluns, Kyle; Jones, David O.; Bochanski, John J.; Pineda, J. Sebastian; Bell, Keaton J.; Kowalski, Adam F.; Davenport, James R. A.; Hawley, Suzanne L.; Schmidt, Sarah J.; Hilton, Eric J.; Bernat, David; Muirhead, Philip; Rojas-Ayala, Barbara; Schlawin, Everett; Gooding, Mary; Dhital, Saurav

2011-01-01

We present a spectroscopic catalog of 70,841 visually inspected M dwarfs from the seventh data release of the Sloan Digital Sky Survey. For each spectrum, we provide measurements of the spectral type, a number of molecular band heads, and the Hα, Hβ, Hγ, Hδ, and Ca II K emission lines. In addition, we calculate the metallicity-sensitive parameter ζ and identify a relationship between ζ and the g - r and r - z colors of M dwarfs. We assess the precision of our spectral types (which were assigned by individual examination), review the bulk attributes of the sample, and examine the magnetic activity properties of M dwarfs, in particular those traced by the higher order Balmer transitions. Our catalog is cross-matched to Two Micron All Sky Survey infrared data, and contains photometric distances for each star. Finally, we identify eight new late-type M dwarfs that are possibly within 25 pc of the Sun. Future studies will use these data to thoroughly examine magnetic activity and kinematics in late-type M dwarfs and examine the chemical and dynamical history of the local Milky Way.

COMMON PROPER-MOTION WIDE WHITE DWARF BINARIES SELECTED FROM THE SLOAN DIGITAL SKY SURVEY

International Nuclear Information System (INIS)

Andrews, Jeff J.; Agüeros, Marcel A.; Belczynski, Krzysztof; Dhital, Saurav; Kleinman, S. J.; West, Andrew A.

2012-01-01

Wide binaries made up of two white dwarfs (WDs) receive far less attention than their tight counterparts. However, our tests using the binary population synthesis code StarTrack indicate that, for any set of reasonable initial conditions, there exists a significant observable population of double white dwarfs (WDWDs) with orbital separations of 10 2 -10 5 AU. We adapt the technique of Dhital et al. to search for candidate common proper-motion WD companions separated by 12,000 spectroscopically confirmed hydrogen-atmosphere WDs recently identified in the Sloan Digital Sky Survey. Using two techniques to separate random alignments from high-confidence pairs, we find nine new high-probability wide WDWDs and confirm three previously identified candidate wide WDWDs. This brings the number of known wide WDWDs to 45; our new pairs are a significant addition to the sample, especially at small proper motions ( –1 ) and large angular separations (>10''). Spectroscopic follow-up and an extension of this method to a larger, photometrically selected set of SDSS WDs may eventually produce a large enough dataset for WDWDs to realize their full potential as testbeds for theories of stellar evolution.

HIDING IN PLAIN SIGHT: RECORD-BREAKING COMPACT STELLAR SYSTEMS IN THE SLOAN DIGITAL SKY SURVEY

International Nuclear Information System (INIS)

Sandoval, Michael A.; Vo, Richard P.; Romanowsky, Aaron J.; Strader, Jay; Choi, Jieun; Conroy, Charlie; Jennings, Zachary G.; Villaume, Alexa; Brodie, Jean P.; Foster, Caroline; Norris, Mark A.; Janz, Joachim; Forbes, Duncan A.

2015-01-01

Motivated by the recent, serendipitous discovery of the densest known galaxy, M60-UCD1, we present two initial findings from a follow-up search, using the Sloan Digital Sky Survey, Subaru/Suprime-Cam, and Hubble Space Telescope imaging, and SOuthern Astrophysical Research (SOAR)/Goodman spectroscopy. The first object discovered, M59-UCD3, has a similar size to M60-UCD1 (half-light radius of r h ∼ 20 pc) but is 40% more luminous (M V ∼ −14.6), making it the new densest-known galaxy. The second, M85-HCC1, has a size like a typical globular cluster (GC; r h ∼ 1.8 pc) but is much more luminous (M V ∼ −12.5). This hypercompact cluster is by far the densest confirmed free-floating stellar system, and is equivalent to the densest known nuclear star clusters. From spectroscopy, we find that both objects are relatively young (∼9 and ∼3 Gyr, respectively), with metal-abundances that resemble those of galaxy centers. Their host galaxies show clear signs of large-scale disturbances, and we conclude that these dense objects are the remnant nuclei of recently accreted galaxies. M59-UCD3 is an ideal target for follow-up with high-resolution imaging and spectroscopy to search for an overweight central supermassive black hole as was discovered in M60-UCD1. These findings also emphasize the potential value of ultra-compact dwarfs and massive GCs as tracers of the assembly histories of galaxies

HIDING IN PLAIN SIGHT: RECORD-BREAKING COMPACT STELLAR SYSTEMS IN THE SLOAN DIGITAL SKY SURVEY

Energy Technology Data Exchange (ETDEWEB)

Sandoval, Michael A.; Vo, Richard P.; Romanowsky, Aaron J. [Department of Physics and Astronomy, San José State University, One Washington Square, San Jose, CA 95192 (United States); Strader, Jay [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Choi, Jieun; Conroy, Charlie [Harvard–Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Jennings, Zachary G.; Villaume, Alexa [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Brodie, Jean P. [University of California Observatories, 1156 High Street, Santa Cruz, CA 95064 (United States); Foster, Caroline [Australian Astronomical Observatory, P.O. Box 915, North Ryde, NSW 1670 (Australia); Norris, Mark A. [Max Planck Institut für Astronomie, Königstuhl 17, D-69117, Heidelberg (Germany); Janz, Joachim; Forbes, Duncan A. [Centre for Astrophysics and Supercomputing, Swinburne University, Hawthorn, VIC 3122 (Australia)

2015-07-20

Motivated by the recent, serendipitous discovery of the densest known galaxy, M60-UCD1, we present two initial findings from a follow-up search, using the Sloan Digital Sky Survey, Subaru/Suprime-Cam, and Hubble Space Telescope imaging, and SOuthern Astrophysical Research (SOAR)/Goodman spectroscopy. The first object discovered, M59-UCD3, has a similar size to M60-UCD1 (half-light radius of r{sub h} ∼ 20 pc) but is 40% more luminous (M{sub V} ∼ −14.6), making it the new densest-known galaxy. The second, M85-HCC1, has a size like a typical globular cluster (GC; r{sub h} ∼ 1.8 pc) but is much more luminous (M{sub V} ∼ −12.5). This hypercompact cluster is by far the densest confirmed free-floating stellar system, and is equivalent to the densest known nuclear star clusters. From spectroscopy, we find that both objects are relatively young (∼9 and ∼3 Gyr, respectively), with metal-abundances that resemble those of galaxy centers. Their host galaxies show clear signs of large-scale disturbances, and we conclude that these dense objects are the remnant nuclei of recently accreted galaxies. M59-UCD3 is an ideal target for follow-up with high-resolution imaging and spectroscopy to search for an overweight central supermassive black hole as was discovered in M60-UCD1. These findings also emphasize the potential value of ultra-compact dwarfs and massive GCs as tracers of the assembly histories of galaxies.

Exploring the diffuse interstellar bands with the Sloan Digital Sky Survey

Science.gov (United States)

Lan, Ting-Wen; Ménard, Brice; Zhu, Guangtun

2015-10-01

We use star, galaxy and quasar spectra taken by the Sloan Digital Sky Survey to map out the distribution of diffuse interstellar bands (DIBs) induced by the Milky Way. After carefully removing the intrinsic spectral energy distribution of each source, we show that by stacking thousands of spectra, it is possible to measure statistical flux fluctuations at the 10-3 level, detect more than 20 DIBs and measure their strength as a function of position on the sky. We create a map of DIB absorption covering about 5000 deg2 and measure correlations with various tracers of the interstellar medium: atomic and molecular hydrogen, dust and polycyclic aromatic hydrocarbons (PAHs). After recovering known correlations, we show that each DIB has a different dependence on atomic and molecular hydrogen: while they are all positively correlated with N_{H I}, they exhibit a range of behaviours with N_{H_2} showing positive, negative or no correlation. We show that a simple parametrization involving only N_{H I} and N_{H_2} applied to all the DIBs is sufficient to reproduce a large collection of observational results reported in the literature: it allows us to naturally describe the relations between DIB strength and dust reddening (including the so-called skin effect), the related scatter, DIB pair-wise correlations and families, the affinity for σ/ζ-type environments and other correlations related to molecules. Our approach allows us to characterize DIB dependencies in a simple manner and provides us with a metric to characterize the similarity between different DIBs.

A CATALOG OF DETAILED VISUAL MORPHOLOGICAL CLASSIFICATIONS FOR 14,034 GALAXIES IN THE SLOAN DIGITAL SKY SURVEY

International Nuclear Information System (INIS)

Nair, Preethi B.; Abraham, Roberto G.

2010-01-01

We present a catalog of detailed visual classifications for 14,034 galaxies in the Sloan Digital Sky Survey (SDSS) Data Release 4 (DR4). Our sample includes nearly all spectroscopically targeted galaxies in the redshift range 0.01 < z < 0.1 down to an apparent extinction-corrected limit of g < 16 mag. In addition to T-Types, we record the existence of bars, rings, lenses, tails, warps, dust lanes, arm flocculence, and multiplicity. This sample defines a comprehensive local galaxy sample which we will use in future papers to study low-redshift morphology. It will also prove useful for calibrating automated galaxy classification algorithms. In this paper, we describe the classification methodology used, detail the systematics and biases of our sample, and summarize the overall statistical properties of the sample, noting the most obvious trends that are relevant for general comparisons of our catalog with previously published work.

Investigations of Short-Timescale Outflow Variability in Quasars of the Sloan Digital Sky Survey

Science.gov (United States)

Hemler, Zachary; Grier, Catherine; Brandt, William; Hall, Patrick; Schneider, Donald; Shen, Yue; Fernandez-Trincado, Jose; SDSS-RM Collaboration

2018-01-01

Quasar outflows are hypothesized to regulate the growth of a quasar's host galaxy and the supermassive black hole (SMBH) itself. Thus, understanding the physics of these outflows is imperative to understanding galactic evolution. The physical properties of these outflows, such as density, radial distance from the SMBH, and kinetic energy can be investigated by measuring both the strength and shape variability of broad absorption lines (BALs) in quasar spectra. However, the accuracy of physical properties calculated using BAL variability methods is limited by the time resolution of the observations. Recent spectral data from the Sloan Digital Sky Survey Reverberation Mapping program (SDSS-RM) provides a novel opportunity to investigate the short-term BAL variability of many quasars at many epochs. The SDSS-RM program took many epochs of spectra for a large sample of quasars over a period of several years, many of which exhibit BALs. The median rest-frame time resolution of these observations is roughly 2 days, in contrast to previous large-sample studies, which typically have time spacing on the order of hundred of days. We are using the SDSS-RM dataset to conduct a BAL variability study that will further constrain outflow properties and provide significant insights into the variability mechanisms of quasar outflows. We are searching for variability in BALs on timescales of less than 2 days among our sample of 22 quasars and determining whether this behavior is common among quasars. We are also investigating the general short-term (less than 10 days) variability characteristics of the entire sample. We will present preliminary results from this study and the possible implications to our understanding of quasar outflows.

OBSERVATIONAL UPPER BOUND ON THE COSMIC ABUNDANCES OF NEGATIVE-MASS COMPACT OBJECTS AND ELLIS WORMHOLES FROM THE SLOAN DIGITAL SKY SURVEY QUASAR LENS SEARCH

Energy Technology Data Exchange (ETDEWEB)

Takahashi, Ryuichi; Asada, Hideki [Faculty of Science and Technology, Hirosaki University, Hirosaki 036-8561 (Japan)

2013-05-01

The latest result in the Sloan Digital Sky Survey Quasar Lens Search (SQLS) has set the first cosmological constraints on negative-mass compact objects and Ellis wormholes. There are no multiple images lensed by the above two exotic objects for {approx}50, 000 distant quasars in the SQLS data. Therefore, an upper bound is put on the cosmic abundances of these lenses. The number density of negative-mass compact objects is n < 10{sup -8}(10{sup -4}) h {sup 3} Mpc{sup -3} at the mass scale |M| > 10{sup 15}(10{sup 12}) M{sub Sun }, which corresponds to the cosmological density parameter |{Omega}| < 10{sup -4} at the galaxy and cluster mass range |M| = 10{sup 12-15} M{sub Sun }. The number density of the Ellis wormhole is n < 10{sup -4} h {sup 3} Mpc{sup -3} for a range of the throat radius a = 10-10{sup 4} pc, which is much smaller than the Einstein ring radius.

Results from a Pilot REU Program: Exploring the Cosmos Using Sloan Digital Sky Survey Data

Science.gov (United States)

Chanover, Nancy J.; Holley-Bockelmann, Kelly; Holtzman, Jon A.

2017-01-01

In the Summer of 2016 we conducted a 10-week pilot Research Experience for Undergraduates (REU) program aimed at increasing the participation of underrepresented minority undergraduate students in research using data from the Sloan Digital Sky Survey (SDSS). This program utilized a distributed REU model, whereby students worked with SDSS scientists on exciting research projects while serving as members of a geographically distributed research community. The format of this REU is similar to that of the SDSS collaboration itself, and since this collaboration structure has become a model for the next generation of large scale astronomical surveys, the students participating in the SDSS REU received early exposure and familiarity with this approach to collaborative scientific research. The SDSS REU also provided the participants with a low-risk opportunity to audition for graduate schools and to explore opportunities afforded by a career as a research scientist. The six student participants were placed at SDSS REU host sites at the Center for Astrophysics at Harvard University, University of Wisconsin-Madison, Vanderbilt University, and the University of Portsmouth. Their research projects covered a broad range of topics related to stars, galaxies, and quasars, all making use of SDSS data. At the start of the summer the REU students participated in a week-long Boot Camp at NMSU, which served as a program orientation, an introduction to skills relevant to their research projects, and an opportunity for team-building and cohort-forming. To foster a sense of community among our distributed students throughout the summer, we conducted a weekly online meeting for all students in the program via virtual meeting tools. These virtual group meetings served two purposes: as a weekly check-in to find out how their projects were progressing, and to conduct professional development seminars on topics of interest and relevance to the REU participants. We discuss the outcomes of this

The Low-Resolution Spectrograph of the Hobby-Eberly Telescope. II. Observations of Quasar Candidates from the Sloan Digital Sky Survey

International Nuclear Information System (INIS)

Schneider, D. P.; Hill, Gary J.; Fan, X.; Ramsey, L. W.; MacQueen, P. J.; Weedman, D. W.; Booth, J. A.; Eracleous, M.; Gunn, J. E.; Lupton, R. H.

2000-01-01

This paper describes spectra of quasar candidates acquired during the commissioning phase of the Low-Resolution Spectrograph of the Hobby-Eberly Telescope. The objects were identified as possible quasars from multicolor image data from the Sloan Digital Sky Survey. The 10 sources had typical r' magnitudes of 19-20, except for one extremely red object with r ' ≅23. The data, obtained with exposure times between 10 and 25 minutes, reveal that the spectra of four candidates are essentially featureless and are not quasars, five are quasars with redshifts between 2.92 and 4.15 (including one broad absorption line quasar), and the red source is a very late M star or early L dwarf. (c) (c) 2000. The Astronomical Society of the Pacific

THE SLOAN DIGITAL SKY SURVEY QUASAR LENS SEARCH. IV. STATISTICAL LENS SAMPLE FROM THE FIFTH DATA RELEASE

International Nuclear Information System (INIS)

Inada, Naohisa; Oguri, Masamune; Shin, Min-Su; Kayo, Issha; Fukugita, Masataka; Strauss, Michael A.; Gott, J. Richard; Hennawi, Joseph F.; Morokuma, Tomoki; Becker, Robert H.; Gregg, Michael D.; White, Richard L.; Kochanek, Christopher S.; Chiu, Kuenley; Johnston, David E.; Clocchiatti, Alejandro; Richards, Gordon T.; Schneider, Donald P.; Frieman, Joshua A.

2010-01-01

We present the second report of our systematic search for strongly lensed quasars from the data of the Sloan Digital Sky Survey (SDSS). From extensive follow-up observations of 136 candidate objects, we find 36 lenses in the full sample of 77,429 spectroscopically confirmed quasars in the SDSS Data Release 5. We then define a complete sample of 19 lenses, including 11 from our previous search in the SDSS Data Release 3, from the sample of 36,287 quasars with i Λ = 0.84 +0.06 -0.08 (stat.) +0.09 -0.07 (syst.) assuming a flat universe, which is in good agreement with other cosmological observations. We also report the discoveries of seven binary quasars with separations ranging from 1.''1 to 16.''6, which are identified in the course of our lens survey. This study concludes the construction of our statistical lens sample in the full SDSS-I data set.

Young stellar populations in early-type galaxies in the Sloan Digital Sky Survey

Science.gov (United States)

Nolan, Louisa A.; Raychaudhury, Somak; Kabán, Ata

2007-02-01

We use a purely data-driven rectified factor analysis to identify early-type galaxies with recent star formation in Data Release 4 of the Sloan Digital Sky Survey Spectroscopic Catalogue. We compare the spectra and environment of these galaxies with those of `normal' early-type galaxies, and a sample of independently selected E+A galaxies. We calculate the projected local galaxy surface density from the nearest five and 10 neighbours (Σ5 and Σ10) for each galaxy in our sample, and find that the dependence on projected local density, of the properties of E+A galaxies, is not significantly different from that of early-type galaxies with young stellar populations, dropping off rapidly towards denser environments, and flattening off at densities ~10 per cent of the stellar mass in these galaxies. This, together with the similarity of the environments in which this `E+F' population and the E+A galaxy sample are found, suggests that E+F galaxies used to be E+A galaxies, but have evolved by a further ~ one to a few Gyr. Our rectified factor analysis is sensitive enough to identify this hidden population, which allows us to study the global and intrinsic properties of early-type galaxies created in major mergers or interactions, and compare them with those early-types which have had the bulk of their stars in place since a much earlier epoch.

COMMON PROPER-MOTION WIDE WHITE DWARF BINARIES SELECTED FROM THE SLOAN DIGITAL SKY SURVEY

Energy Technology Data Exchange (ETDEWEB)

Andrews, Jeff J.; Agueeros, Marcel A. [Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027 (United States); Belczynski, Krzysztof [Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warsaw (Poland); Dhital, Saurav [Department of Physics and Astronomy, Vanderbilt University, 6301 Stevenson Center, Nashville, TN 37235 (United States); Kleinman, S. J. [Gemini Observatory, Northern Operations Center, Hilo, HI 96720 (United States); West, Andrew A. [Department of Astronomy, Boston University, 725 Commonwealth Ave, Boston, MA 02215 (United States)

2012-10-01

Wide binaries made up of two white dwarfs (WDs) receive far less attention than their tight counterparts. However, our tests using the binary population synthesis code StarTrack indicate that, for any set of reasonable initial conditions, there exists a significant observable population of double white dwarfs (WDWDs) with orbital separations of 10{sup 2}-10{sup 5} AU. We adapt the technique of Dhital et al. to search for candidate common proper-motion WD companions separated by <10' around the >12,000 spectroscopically confirmed hydrogen-atmosphere WDs recently identified in the Sloan Digital Sky Survey. Using two techniques to separate random alignments from high-confidence pairs, we find nine new high-probability wide WDWDs and confirm three previously identified candidate wide WDWDs. This brings the number of known wide WDWDs to 45; our new pairs are a significant addition to the sample, especially at small proper motions (<200 mas yr{sup -1}) and large angular separations (>10''). Spectroscopic follow-up and an extension of this method to a larger, photometrically selected set of SDSS WDs may eventually produce a large enough dataset for WDWDs to realize their full potential as testbeds for theories of stellar evolution.

The Supernova Legacy Survey: Measurement of Omega_M, Omega_Lambda,and w from the First Year Data Set

Energy Technology Data Exchange (ETDEWEB)

Astier, P.; Guy, J.; Regnault, N.; Pain, R.; Aubourg, E.; Balam,D.; Basa, S.; Carlberg, R.G.; Fabbro, S.; Fouchez, D.; Hook, I.M.; Howell, D.A.; Lafoux, H.; Neill, J.D.; Palanque-Delabrouille, N.; Perrett, K.; Pritchet, C.J.; Rich, J.; Sullivan, M.; Taillet, R.; Aldering, G.; Antilogus, P.; Arsenijevic, V.; Balland, C.; Baumont, S.; Bronder, J.; Courtois, H.; Ellis, R.S.; Filiol, M.; Goncalves, A.C.; Goobar, A.; Guide, D.; Hardin, D.; Lusset, V.; Lidman, C.; McMahon, R.; Mouchet, M.; Mourao, A.; Perlmutter, S.; Ripoche, P.; Tao, C.; Walton, N.

2005-10-14

We present distance measurements to 71 high redshift type Ia supernovae discovered during the first year of the 5-year Supernova Legacy Survey (SNLS). These events were detected and their multi-color light-curves measured using the MegaPrime/MegaCam instrument at the Canada-France-Hawaii Telescope (CFHT), by repeatedly imaging four one-square degree fields in four bands. Follow-up spectroscopy was performed at the VLT, Gemini and Keck telescopes to confirm the nature of the supernovae and to measure their redshift. With this data set, we have built a Hubble diagram extending to z = 1, with all distance measurements involving at least two bands. Systematic uncertainties are evaluated making use of the multiband photometry obtained at CFHT. Cosmological fits to this first year SNLS Hubble diagram give the following results: {Omega}{sub M} = 0.263 {+-} 0.042 (stat) {+-} 0.032 (sys) for a flat {Lambda}CDM model; and w = -1.023 {+-} 0.090 (stat) {+-} 0.054 (sys) for a flat cosmology with constant equation of state w when combined with the constraint from the recent Sloan Digital Sky Survey measurement of baryon acoustic oscillations.

The Supernova Legacy Survey: Measurement of Omega_M, Omega_Lambda, and w from the First Year Data Set

Science.gov (United States)

Astier, P.; Guy, J.; Regnault, N.; Pain, R.; Aubourg, E.; Balam, D.; Basa, S.; Carlberg, R. G.; Fabbro, S.; Fouchez, D.; Hook, I. M.; Howell, D. A.; Lafoux, H.; Neill, J. D.; Palanque-Delabrouille, N.; Perrett, K.; Pritchet, C. J.; Rich, J.; Sullivan, M.; Taillet, R.; Aldering, G.; Antilogus, P.; Arsenijevic, V.; Balland, C.; Baumont, S.; Bronder, J.; Courtois, H.; Ellis, R. S.; Filiol, M.; Goncalves, A. C.; Goobar, A.; Guide, D.; Hardin, D.; Lusset, V.; Lidman, C.; McMahon, R.; Mouchet, M.; Mourao, A.; Perlmutter, S.; Ripoche, P.; Tao, C.; Walton, N.

2005-10-14

We present distance measurements to 71 high redshift type Ia supernovae discovered during the first year of the 5-year Supernova Legacy Survey (SNLS). These events were detected and their multi-color light-curves measured using the MegaPrime/MegaCam instrument at the Canada-France-Hawaii Telescope (CFHT), by repeatedly imaging four one-square degree fields in four bands. Follow-up spectroscopy was performed at the VLT, Gemini and Keck telescopes to confirm the nature of the supernovae and to measure their redshift. With this data set, we have built a Hubble diagram extending to z = 1, with all distance measurements involving at least two bands. Systematic uncertainties are evaluated making use of the multiband photometry obtained at CFHT. Cosmological fits to this first year SNLS Hubble diagram give the following results: {Omega}{sub M} = 0.263 {+-} 0.042 (stat) {+-} 0.032 (sys) for a flat {Lambda}CDM model; and w = -1.023 {+-} 0.090 (stat) {+-} 0.054 (sys) for a flat cosmology with constant equation of state w when combined with the constraint from the recent Sloan Digital Sky Survey measurement of baryon acoustic oscillations.

TOPOLOGY OF LUMINOUS RED GALAXIES FROM THE SLOAN DIGITAL SKY SURVEY

International Nuclear Information System (INIS)

Choi, Yun-Young; Kim, Juhan; Rossi, Graziano; Kim, Sungsoo S.; Lee, Jeong-Eun

2013-01-01

We present measurements of the genus topology of luminous red galaxies (LRGs) from the Sloan Digital Sky Survey (SDSS) Data Release 7 catalog, with unprecedented statistical significance. To estimate the uncertainties in the measured genus, we construct 81 mock SDSS LRG surveys along the past light cone from Horizon Run 3, one of the largest N-body simulations to date, which evolved 7210 3 particles in a 10,815 h –1  Mpc box. After carefully modeling and removing all known systematic effects due to finite pixel size, survey boundary, radial and angular selection functions, shot noise, and galaxy biasing, we find that the observed genus amplitude reaches 272 at a 22 h –1  Mpc smoothing scale, with an uncertainty of 4.2%; the estimated error fully incorporates cosmic variance. This is the most accurate constraint on the genus amplitude to date and significantly improves on our previous results. In particular, the shape of the genus curve agrees very well with the mean topology of the SDSS LRG mock surveys in a Λ cold dark matter universe. However, comparison with simulations also shows small deviations of the observed genus curve from the theoretical expectation for Gaussian initial conditions. While these discrepancies are mainly driven by known systematic effects such as shot noise and redshift-space distortions, they do contain important cosmological information on the physical effects connected with galaxy formation, gravitational evolution, and primordial non-Gaussianity. We address the key role played by systematics on the genus curve and show how to accurately correct for their effects to recover the topology of the underlying matter. A future work will provide an interpretation of these deviations in the context of the local model of non-Gaussianity

A SYSTEMATIC SEARCH FOR MASSIVE BLACK HOLE BINARIES IN THE SLOAN DIGITAL SKY SURVEY SPECTROSCOPIC SAMPLE

International Nuclear Information System (INIS)

Tsalmantza, P.; Decarli, R.; Hogg, David W.; Dotti, M.

2011-01-01

We present the results of a systematic search for massive black hole binaries in the Sloan Digital Sky Survey (SDSS) spectroscopic database. We focus on bound binaries, under the assumption that one of the black holes is active. In this framework, the broad lines associated with the accreting black hole are expected to show systematic velocity shifts with respect to the narrow lines, which trace the rest frame of the galaxy. For a sample of 54,586 quasars and 3929 galaxies at redshifts 0.1 < z < 1.5, we brute-force model each spectrum as a mixture of two quasars at two different redshifts. The spectral model is a data-driven dimensionality reduction of the SDSS quasar spectra based on a matrix factorization. We identified 32 objects with peculiar spectra. Nine of them can be interpreted as black hole binaries. This doubles the number of known black hole binary candidates. We also report on the discovery of a new class of extreme double-peaked emitters with exceptionally broad and faint Balmer lines. For all the interesting sources, we present detailed analysis of the spectra and discuss possible interpretations.

A RADIO SEARCH FOR PULSAR COMPANIONS TO SLOAN DIGITAL SKY SURVEY LOW-MASS WHITE DWARFS

International Nuclear Information System (INIS)

Agueeros, Marcel A.; Camilo, Fernando; Silvestri, Nicole M.; Anderson, Scott F.; Kleinman, S. J.; Liebert, James W.

2009-01-01

We have conducted a search for pulsar companions to 15 low-mass white dwarfs (LMWDs; M sun ) at 820 MHz with the NRAO Green Bank Telescope (GBT). These LMWDs were spectroscopically identified in the Sloan Digital Sky Survey (SDSS), and do not show the photometric excess or spectroscopic signature associated with a companion in their discovery data. However, LMWDs are believed to evolve in binary systems and to have either a more massive white dwarf (WD) or a neutron star (NS) as a companion. Indeed, evolutionary models of low-mass X-ray binaries, the precursors of millisecond pulsars (MSPs), produce significant numbers of LMWDs, suggesting that the SDSS LMWDs may have NS companions. No convincing pulsar signal is detected in our data. This is consistent with the findings of van Leeuwen et al., who conducted a GBT search for radio pulsations at 340 MHz from unseen companions to eight SDSS WDs (five are still considered LMWDs; the three others are now classified as 'ordinary' WDs). We discuss the constraints our nondetections place on the probability P MSP that the companion to a given LMWD is a radio pulsar in the context of the luminosity and acceleration limits of our search; we find that P MSP +4 -2 %.

The Sloan Digital Sky Survey Quasar Lens Search. VI. Constraints on Dark Energy and the Evolution of Massive Galaxies

Energy Technology Data Exchange (ETDEWEB)

Oguri, Masamune [Univ. of Tokyo (Japan); et al.

2012-05-01

We present a statistical analysis of the final lens sample from the Sloan Digital Sky Survey Quasar Lens Search (SQLS). The number distribution of a complete subsample of 19 lensed quasars selected from 50,836 source quasars is compared with theoretical expectations, with particular attention to the selection function. Assuming that the velocity function of galaxies does not evolve with redshift, the SQLS sample constrains the cosmological constant to \\Omega_\\Lambda=0.79^{+0.06}_{-0.07}(stat.)^{+0.06}_{-0.06}(syst.) for a flat universe. The dark energy equation of state is found to be consistent with w=-1 when the SQLS is combined with constraints from baryon acoustic oscillation (BAO) measurements or results from the Wilkinson Microwave Anisotropy Probe (WMAP). We also obtain simultaneous constraints on cosmological parameters and redshift evolution of the galaxy velocity function, finding no evidence for redshift evolution at z<1 in any combinations of constraints. For instance, number density evolution quantified as \

SLOAN DIGITAL SKY SURVEY OBSERVATIONS OF KUIPER BELT OBJECTS: COLORS AND VARIABILITY

International Nuclear Information System (INIS)

Ofek, Eran O.

2012-01-01

Colors of trans-Neptunian objects (TNOs) are used to study the evolutionary processes of bodies in the outskirts of the solar system and to test theories regarding their origin. Here I describe a search for serendipitous Sloan Digital Sky Survey (SDSS) observations of known TNOs and Centaurs. I present a catalog of SDSS photometry, colors, and astrometry of 388 measurements of 42 outer solar system objects. I find weak evidence, at the ≈ 2σ level (per trial), for a correlation between the g – r color and inclination of scattered disk objects and hot classical Kuiper Belt objects. I find a correlation between the g – r color and the angular momentum in the z direction of all the objects in this sample. These findings should be verified using larger samples of TNOs. Light curves as a function of phase angle are constructed for 13 objects. The steepness of the slopes of these light curves suggests that the coherent backscatter mechanism plays a major role in the reflectivity of outer solar system small objects at small phase angles. I find weak evidence for an anticorrelation, significant at the 2σ confidence level (per trial), between the g-band phase-angle slope parameter and the semimajor axis, as well as the aphelion distance, of these objects (i.e., they show a more prominent 'opposition effect' at smaller distances from the Sun). However, this plausible correlation should be verified using a larger sample. I discuss the origin of this possible correlation and argue that if this correlation is real it probably indicates that 'Sedna'-like objects have a different origin than other classes of TNOs. Finally, I identify several objects with large variability amplitudes.

The First Digit 1

Indian Academy of Sciences (India)

IAS Admin

1075. RESONANCE | December 2013. GENERAL | ARTICLE. Table 2. The first digits distri- bution according to Benford's law. First Frequency. Digit. 1. 30.1 %. 2. 17.6 %. 3. 12.4 %. 4. 9.7 %. 5. 7.9 %. 6. 6.7 %. 7. 5.8 %. 8. 5.1 %. 9. 4.5 % ...

First year university student engagement using digital curation and career goal setting

Directory of Open Access Journals (Sweden)

Amy Antonio

2015-10-01

Full Text Available The engagement of students is one of the most pressing issues facing higher education in the 21st century. Around the world, participation rates in tertiary education are on the rise and one of the key challenges facing educators is finding ways to engage these students. We present the results of a project that assesses the impact of an engagement strategy in which a cohort of students entering their first year of university (1 establish and maintain a clear goal of their ideal future career and (2 make use of a web-based digital curation tool to research and present their findings. The results demonstrate the effectiveness of the strategy, which could arguably be applied to a broad range of disciplines given that the majority of students today are technologically literate.

The dependence of galaxy clustering on tidal environment in the Sloan Digital Sky Survey

Science.gov (United States)

Paranjape, Aseem; Hahn, Oliver; Sheth, Ravi K.

2018-06-01

The influence of the Cosmic Web on galaxy formation and evolution is of great observational and theoretical interest. We investigate whether the Cosmic Web leaves an imprint in the spatial clustering of galaxies in the Sloan Digital Sky Survey (SDSS), using the group catalogue of Yang et al. and tidal field estimates at ˜2 h-1 Mpc scales from the mass-tides-velocity data set of Wang et al. We use the tidal anisotropy α (Paranjape et al.) to characterize the tidal environment of groups, and measure the redshift-space 2-point correlation function (2pcf) of group positions and the luminosity- and colour-dependent clustering of group galaxies using samples segregated by α. We find that all the 2pcf measurements depend strongly on α, with factors of ˜20 between the large-scale 2pcf of objects in the most and least isotropic environments. To test whether these strong trends imply `beyond halo mass' effects for galaxy evolution, we compare our results with corresponding 2pcf measurements in mock catalogues constructed using a halo occupation distribution that uses only halo mass as an input. We find that this prescription qualitatively reproduces all observed trends, and also quantitatively matches many of the observed results. Although there are some statistically significant differences between our `halo mass only' mocks and the data - in the most and least isotropic environments - which deserve further investigation, our results suggest that if the tidal environment induces additional effects on galaxy properties other than those inherited from their host haloes, then these must be weak.

First Invenio Workshop: CERN’s digital library software ten years on

CERN Multimedia

Joannah Caborn Wengler

2012-01-01

To mark the release of Invenio 1.0, the first User Group Workshop was held last week, with more than 40 developers, system administrators and librarians from 14 different countries attending. The participants were able to catch up on developments in CERN’s digital library software and get a glimpse of where it's going next.   “This is the first time we’ve held such a big workshop,” explains Jean-Yves Le Meur, head of Digital Library Services. “There was a lot of demand for an event like this, and bringing out version 1.0 of Invenio was an obvious time to do it.” Ask him what’s new in version 1.0 and he opens his eyes wide. “There’s so much, it’s hard to summarise. One key improvement is that the code and the database are stable, well tested and optimised, which makes the software more efficient.” The participants, on the other hand, highlight new features coming up in Invenio...

THE SLOAN DIGITAL SKY SURVEY REVERBERATION MAPPING PROJECT: RAPID C iv BROAD ABSORPTION LINE VARIABILITY

International Nuclear Information System (INIS)

Grier, C. J.; Brandt, W. N.; Trump, J. R.; Schneider, D. P.; Hall, P. B.; Shen, Yue; Vivek, M.; Dawson, K. S.; Ak, N. Filiz; Chen, Yuguang; Denney, K. D.; Kochanek, C. S.; Peterson, B. M.; Green, Paul J.; Jiang, Linhua; McGreer, Ian D.; Pâris, I.; Tao, Charling; Wood-Vasey, W. M.; Bizyaev, Dmitry

2015-01-01

We report the discovery of rapid variations of a high-velocity C iv broad absorption line trough in the quasar SDSS J141007.74+541203.3. This object was intensively observed in 2014 as a part of the Sloan Digital Sky Survey Reverberation Mapping Project, during which 32 epochs of spectroscopy were obtained with the Baryon Oscillation Spectroscopic Survey spectrograph. We observe significant (>4σ) variability in the equivalent width (EW) of the broad (∼4000 km s −1 wide) C iv trough on rest-frame timescales as short as 1.20 days (∼29 hr), the shortest broad absorption line variability timescale yet reported. The EW varied by ∼10% on these short timescales, and by about a factor of two over the duration of the campaign. We evaluate several potential causes of the variability, concluding that the most likely cause is a rapid response to changes in the incident ionizing continuum. If the outflow is at a radius where the recombination rate is higher than the ionization rate, the timescale of variability places a lower limit on the density of the absorbing gas of n e ≳ 3.9 × 10 5 cm −3 . The broad absorption line variability characteristics of this quasar are consistent with those observed in previous studies of quasars, indicating that such short-term variability may in fact be common and thus can be used to learn about outflow characteristics and contributions to quasar/host-galaxy feedback scenarios

A plausible (overlooked) super-luminous supernova in the Sloan digital sky survey stripe 82 data

International Nuclear Information System (INIS)

Kostrzewa-Rutkowska, Zuzanna; Kozłowski, Szymon; Wyrzykowski, Łukasz; Djorgovski, S. George; Mahabal, Ashish A.; Glikman, Eilat; Koposov, Sergey

2013-01-01

We present the discovery of a plausible super-luminous supernova (SLSN), found in the archival data of Sloan Digital Sky Survey (SDSS) Stripe 82, called PSN 000123+000504. The supernova (SN) peaked at m g < 19.4 mag in the second half of 2005 September, but was missed by the real-time SN hunt. The observed part of the light curve (17 epochs) showed that the rise to the maximum took over 30 days, while the decline time lasted at least 70 days (observed frame), closely resembling other SLSNe of SN 2007bi type. The spectrum of the host galaxy reveals a redshift of z = 0.281 and the distance modulus of μ = 40.77 mag. Combining this information with the SDSS photometry, we found the host galaxy to be an LMC-like irregular dwarf galaxy with an absolute magnitude of M B = –18.2 ± 0.2 mag and an oxygen abundance of 12+log [O/H]=8.3±0.2; hence, the SN peaked at M g < –21.3 mag. Our SLSN follows the relation for the most energetic/super-luminous SNe exploding in low-metallicity environments, but we found no clear evidence for SLSNe to explode in low-luminosity (dwarf) galaxies only. The available information on the PSN 000123+000504 light curve suggests the magnetar-powered model as a likely scenario of this event. This SLSN is a new addition to a quickly growing family of super-luminous SNe.

Discovery of two gravitationally lensed quasars with image separations of 3 arcseconds from the Sloan Digital Sky Survey

Energy Technology Data Exchange (ETDEWEB)

Oguri, Masamune; Inada, Naohisa; Hennawi, Joseph F.; Richards, Gordon T.; Johnston, David E.; Frieman, Joshua A.; Pindor, Bartosz; Strauss, Michael A.; Brunner, Robert; Becker, Robert H.; Castander, Francisco J.; Gregg, Michael D.; Hall, Patrick B.; Rix, Hans-Walter; Schneider, Donald P.; Bahcall, Neta A.; Brinkmann, Jonathan; York, Donald G.

2004-11-01

We report the discovery of two doubly-imaged quasars, SDSS J100128.61+502756.9 and SDSS J120629.65+433217.6, at redshifts of 1.838 and 1.789 and with image separations of 2.86'' and 2.90'', respectively. The objects were selected as lens candidates from the Sloan Digital Sky Survey (SDSS). Based on the identical nature of the spectra of the two quasars in each pair and the identification of the lens galaxies, we conclude that the objects are gravitational lenses. The lenses are complicated; in both systems there are several galaxies in the fields very close to the quasars, in addition to the lens galaxies themselves. The lens modeling implies that these nearby galaxies contribute significantly to the lens potentials. On larger scales, we have detected an enhancement in the galaxy density near SDSS J100128.61+502756.9. The number of lenses with image separation of {approx} 3'' in the SDSS already exceeds the prediction of simple theoretical models based on the standard Lambda-dominated cosmology and observed velocity function of galaxies.

M DWARFS IN SLOAN DIGITAL SKY SURVEY STRIPE 82: PHOTOMETRIC LIGHT CURVES AND FLARE RATE ANALYSIS

International Nuclear Information System (INIS)

Kowalski, Adam F.; Hawley, Suzanne L.; Hilton, Eric J.; Becker, Andrew C.; Sesar, Branimir; West, Andrew A.; Bochanski, John J.

2009-01-01

We present a flare rate analysis of 50,130 M dwarf light curves in Sloan Digital Sky Survey Stripe 82. We identified 271 flares using a customized variability index to search ∼2.5 million photometric observations for flux increases in the u and g bands. Every image of a flaring observation was examined by eye and with a point-spread function-matching and image subtraction tool to guard against false positives. Flaring is found to be strongly correlated with the appearance of Hα in emission in the quiet spectrum. Of the 99 flare stars that have spectra, we classify eight as relatively inactive. The flaring fraction is found to increase strongly in stars with redder colors during quiescence, which can be attributed to the increasing flare visibility and increasing active fraction for redder stars. The flaring fraction is strongly correlated with |Z| distance such that most stars that flare are within 300 pc of the Galactic plane. We derive flare u-band luminosities and find that the most luminous flares occur on the earlier-type m dwarfs. Our best estimate of the lower limit on the flaring rate (averaged over Stripe 82) for flares with Δu ≥ 0.7 mag on stars with u -1 deg -2 but can vary significantly with the line of sight.

THE SLOAN DIGITAL SKY SURVEY DATA RELEASE 7 SPECTROSCOPIC M DWARF CATALOG. II. STATISTICAL PARALLAX ANALYSIS

International Nuclear Information System (INIS)

Bochanski, John J.; Hawley, Suzanne L.; West, Andrew A.

2011-01-01

We present a statistical parallax analysis of low-mass dwarfs from the Sloan Digital Sky Survey. We calculate absolute r-band magnitudes (M r ) as a function of color and spectral type and investigate changes in M r with location in the Milky Way. We find that magnetically active M dwarfs are intrinsically brighter in M r than their inactive counterparts at the same color or spectral type. Metallicity, as traced by the proxy ζ, also affects M r , with metal-poor stars having fainter absolute magnitudes than higher metallicity M dwarfs at the same color or spectral type. Additionally, we measure the velocity ellipsoid and solar reflex motion for each subsample of M dwarfs. We find good agreement between our measured solar peculiar motion and previous results for similar populations, as well as some evidence for differing motions of early and late M-type populations in U and W velocities that cannot be attributed to asymmetric drift. The reflex solar motion and the velocity dispersions both show that younger populations, as traced by magnetic activity and location near the Galactic plane, have experienced less dynamical heating. We introduce a new parameter, the independent position altitude (IPA), to investigate populations as a function of vertical height from the Galactic plane. M dwarfs at all types exhibit an increase in velocity dispersion when analyzed in comparable IPA subgroups.

The Discovery of a High-Redshift Quasar without Emission Lines from Sloan Digital Sky Survey Commissioning Data.

Science.gov (United States)

Fan; Strauss; Gunn; Lupton; Carilli; Rupen; Schmidt; Moustakas; Davis; Annis; Bahcall; Brinkmann; Brunner; Csabai; Doi; Fukugita; Heckman; Hennessy; Hindsley; Ivezic; Knapp; Lamb; Munn; Pauls; Pier; Rockosi; Schneider; Szalay; Tucker; York

1999-12-01

We report observations of a luminous unresolved object at redshift z=4.62, with a featureless optical spectrum redward of the Lyalpha forest region, discovered from Sloan Digital Sky Survey commissioning data. The redshift is determined by the onset of the Lyalpha forest at lambda approximately 6800 Å and a Lyman limit system at lambda=5120 Å. A strong Lyalpha absorption system with weak metal absorption lines at z=4.58 is also identified in the spectrum. The object has a continuum absolute magnitude of -26.6 at 1450 Å in the rest frame (h0=0.5, q0=0.5) and therefore cannot be an ordinary galaxy. It shows no radio emission (the 3 sigma upper limit of its flux at 6 cm is 60 µJy), indicating a radio-to-optical flux ratio at least as small as that of the radio-weakest BL Lacertae objects known. It is also not linearly polarized to a 3 sigma upper limit of 4% in the observed I band. Therefore, it is either the most distant BL Lac object known to date, with very weak radio emission, or a new type of unbeamed quasar, whose broad emission line region is very weak or absent.

SPECTROSCOPIC ORBITAL PERIODS FOR 29 CATACLYSMIC VARIABLES FROM THE SLOAN DIGITAL SKY SURVEY

Energy Technology Data Exchange (ETDEWEB)

Thorstensen, John R.; Taylor, Cynthia J.; Peters, Christopher S.; Skinner, Julie N. [Department of Physics and Astronomy 6127 Wilder Laboratory, Dartmouth College Hanover, NH 03755-3528 (United States); Southworth, John [Astrophysics Group Keele University Staffordshire ST5 5BG (United Kingdom); Gänsicke, Boris T. [Department of Physics University of Warwick Coventry CV4 7AL (United Kingdom)

2015-04-15

We report follow-up spectroscopy of 29 cataclysmic variables from the Sloan Digital Sky Survey (SDSS), 22 of which were discovered by SDSS and seven of which are previously known systems that were recovered in SDSS. The periods for 16 of these objects were included in the tabulation by Gänsicke et al. While most of the systems have periods less than 2 hr, only one has a period in the 80–86 minutes “spike” found by Gänsicke et al., and 11 have periods longer than 3 hr, indicating that the present sample is skewed toward longer-period, higher-luminosity objects. Seven of the objects have spectra resembling dwarf novae, but have apparently never been observed in outburst, suggesting that many cataclysmics with relatively low variability amplitude remain to be discovered. Some of the objects are notable. SDSS J07568+0858 and SDSS J08129+1911 were previously known to have deep eclipses; in addition to spectroscopy, we use archival data from the Catalina Real Time Transient Survey to refine their periods. We give a parallax-based distance of 195 (+54, −39) pc for LV Cnc (SDSS J09197+0857), which at P{sub orb} = 81 m has the shortest orbital period in our sample. SDSS J08091+3814 shows both the spectroscopic phase offset and phase-dependent absorption found in SW Sextantis stars. The average spectra of SDSS J08055+0720 and SDSS J16191+1351 show contributions from K-type secondaries, and SDSS J080440+0239 shows a contribution from an early M star. We use these to constrain the distances. SDSS J09459+2922 has characteristics typical of a magnetic system. SDSS11324+6249 may be a novalike variable, and if so, its orbital period (99 minutes) is unusually short for that subclass.

SYSTEMATIC SEARCH FOR EXTREMELY METAL-POOR GALAXIES IN THE SLOAN DIGITAL SKY SURVEY

Energy Technology Data Exchange (ETDEWEB)

Morales-Luis, A. B.; Sanchez Almeida, J.; Aguerri, J. A. L.; Munoz-Tunon, C., E-mail: abml@iac.es, E-mail: jos@iac.es, E-mail: cmt@iac.es, E-mail: jalfonso@iac.es [Instituto de Astrofisica de Canarias, E-38205 La Laguna, Tenerife (Spain)

2011-12-10

We carry out a systematic search for extremely metal-poor (XMP) galaxies in the spectroscopic sample of Sloan Digital Sky Survey (SDSS) data release 7 (DR7). The XMP candidates are found by classifying all the galaxies according to the form of their spectra in a region 80 A wide around H{alpha}. Due to the data size, the method requires an automatic classification algorithm. We use k-means. Our systematic search renders 32 galaxies having negligible [N II] lines, as expected in XMP galaxy spectra. Twenty-one of them have been previously identified as XMP galaxies in the literature-the remaining 11 are new. This was established after a thorough bibliographic search that yielded only some 130 galaxies known to have an oxygen metallicity 10 times smaller than the Sun (explicitly, with 12 + log (O/H) {<=} 7.65). XMP galaxies are rare; they represent 0.01% of the galaxies with emission lines in SDSS/DR7. Although the final metallicity estimate of all candidates remains pending, strong-line empirical calibrations indicate a metallicity about one-tenth solar, with the oxygen metallicity of the 21 known targets being 12 + log (O/H) {approx_equal} 7.61 {+-} 0.19. Since the SDSS catalog is limited in apparent magnitude, we have been able to estimate the volume number density of XMP galaxies in the local universe, which turns out to be (1.32 {+-} 0.23) Multiplication-Sign 10{sup -4} Mpc{sup -3}. The XMP galaxies constitute 0.1% of the galaxies in the local volume, or {approx}0.2% considering only emission-line galaxies. All but four of our candidates are blue compact dwarf galaxies, and 24 of them have either cometary shape or are formed by chained knots.

THE MILKY WAY TOMOGRAPHY WITH SLOAN DIGITAL SKY SURVEY. IV. DISSECTING DUST

International Nuclear Information System (INIS)

Berry, Michael; Ivezić, Željko; Brooks, Keira J.; Gibson, Robert R.; Jones, Lynne; Yoachim, Peter; Krughoff, Simon; Connolly, Andrew J.; Loebman, Sarah; Sesar, Branimir; Jurić, Mario; Schlafly, Edward F.; Finkbeiner, Douglas; Bellovary, Jillian; Vrbanec, Dijana; Beers, Timothy C.; Schneider, Donald P.; Kimball, Amy; Bond, Nicholas A.; Schlegel, David

2012-01-01

We use Sloan Digital Sky Survey (SDSS) photometry of 73 million stars to simultaneously constrain best-fit main-sequence stellar spectral energy distribution (SED) and amount of dust extinction along the line of sight toward each star. Using a subsample of 23 million stars with Two Micron All Sky Survey (2MASS) photometry, whose addition enables more robust results, we show that SDSS photometry alone is sufficient to break degeneracies between intrinsic stellar color and dust amount when the shape of extinction curve is fixed. When using both SDSS and 2MASS photometry, the ratio of the total to selective absorption, R V , can be determined with an uncertainty of about 0.1 for most stars in high-extinction regions. These fits enable detailed studies of the dust properties and its spatial distribution, and of the stellar spatial distribution at low Galactic latitudes (|b| V = 3.0 ± 0.1(random)±0.1 (systematic) over most of the high-latitude sky. At low Galactic latitudes (|b| V and find that R V = 3.1 cannot be ruled out in any of the 10 SEGUE stripes at a precision level of ∼0.1-0.2. Our best estimate for the intrinsic scatter of R V in the regions probed by SEGUE stripes is ∼0.2. We introduce a method for efficient selection of candidate red giant stars in the disk, dubbed 'dusty parallax relation', which utilizes a correlation between distance and the extinction along the line of sight. We make these best-fit parameters, as well as all the input SDSS and 2MASS data, publicly available in a user-friendly format. These data can be used for studies of stellar number density distribution, the distribution of dust properties, for selecting sources whose SED differs from SEDs for high-latitude main-sequence stars, and for estimating distances to dust clouds and, in turn, to molecular gas clouds.

A hot white dwarf luminosity function from the Sloan Digital Sky Survey

Science.gov (United States)

Krzesinski, J.; Kleinman, S. J.; Nitta, A.; Hügelmeyer, S.; Dreizler, S.; Liebert, J.; Harris, H.

2009-12-01

Aims. We present a hot white dwarf (WD) luminosity function (LF) using data taken from the Sloan Digital Sky Survey (SDSS) Data Release 4. We present and discuss a combined LF, along with separate DA and non-DA as LFs. We explore the completeness of our LFs and interpret a sudden drop in the non-DA LF near 2 M_bol as a transition of the non-DA WD atmosphere into the DA one during WD evolution. Our LF extends roughly between -0.5 T_eff > ˜25 000 K. Our LF should now be useful for estimates of recent star formation and for studies of neutrino and other potential particle emission losses in hot WDs. Methods: To create a sample whose completeness can be characterized fully, we used stars whose spectra were obtained via the SDSS's “hot standard” target selection criteria. The hot standard stars were purposefully targeted to a high level of completeness by the SDSS for calibration purposes. We are fortunate that many of them are hot white dwarfs stars. We further limited the sample to stars with fitted temperatures exceeding 23 500 K and log{g} > 7.0. We determined stellar distances for our sample based on their absolute SDSS g filter magnitudes, derived from WD stellar atmosphere model fits to the SDSS stellar spectra. Results: We compared our LF with those of other researchers where overlap occurs; however, our LFs are unique in their extension to the most luminous/hottest WDs. The cool end of our LF connects with the hot end of previously determined SDSS WD LFs and agreement here is quite good. It is also good with previous non-SDSS WD LFs. We note distinct differences between the DA and non-DA LFs and discuss the reliability of the DA LF at its hot end. We have extended the range of luminosities covered in the most recent WD LFs. The SDSS sample is understood quite well and its exploration should contribute to a number of new insights into early white dwarf evolution.

THE SLOAN DIGITAL SKY SURVEY REVERBERATION MAPPING PROJECT: RAPID C iv BROAD ABSORPTION LINE VARIABILITY

Energy Technology Data Exchange (ETDEWEB)

Grier, C. J.; Brandt, W. N.; Trump, J. R.; Schneider, D. P. [Department of Astronomy and Astrophysics and Institute for Gravitation and the Cosmos, The Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Hall, P. B. [Department of Physics and Astronomy, York University, Toronto, ON M3J 1P3 (Canada); Shen, Yue [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Vivek, M.; Dawson, K. S. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Ak, N. Filiz [Faculty of Sciences, Department of Astronomy and Space Sciences, Erciyes University, 38039 Kayseri (Turkey); Chen, Yuguang [Department of Astronomy, School of Physics, Peking University, Beijing 100871 (China); Denney, K. D.; Kochanek, C. S.; Peterson, B. M. [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Green, Paul J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Jiang, Linhua [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China); McGreer, Ian D. [Steward Observatory, The University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721-0065 (United States); Pâris, I. [INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, I-34131 Trieste (Italy); Tao, Charling [Centre de Physique des Particules de Marseille, Aix-Marseille Universite, CNRS /IN2P3, 163, avenue de Luminy, Case 902, F-13288 Marseille Cedex 09 (France); Wood-Vasey, W. M. [PITT PACC, Department of Physics and Astronomy, University of Pittsburgh, 3941 O’Hara Street, Pittsburgh, PA 15260 (United States); Bizyaev, Dmitry, E-mail: grier@psu.edu [Apache Point Observatory and New Mexico State University, P.O. Box 59, Sunspot, NM, 88349-0059 (United States); and others

2015-06-10

We report the discovery of rapid variations of a high-velocity C iv broad absorption line trough in the quasar SDSS J141007.74+541203.3. This object was intensively observed in 2014 as a part of the Sloan Digital Sky Survey Reverberation Mapping Project, during which 32 epochs of spectroscopy were obtained with the Baryon Oscillation Spectroscopic Survey spectrograph. We observe significant (>4σ) variability in the equivalent width (EW) of the broad (∼4000 km s{sup −1} wide) C iv trough on rest-frame timescales as short as 1.20 days (∼29 hr), the shortest broad absorption line variability timescale yet reported. The EW varied by ∼10% on these short timescales, and by about a factor of two over the duration of the campaign. We evaluate several potential causes of the variability, concluding that the most likely cause is a rapid response to changes in the incident ionizing continuum. If the outflow is at a radius where the recombination rate is higher than the ionization rate, the timescale of variability places a lower limit on the density of the absorbing gas of n{sub e} ≳ 3.9 × 10{sup 5} cm{sup −3}. The broad absorption line variability characteristics of this quasar are consistent with those observed in previous studies of quasars, indicating that such short-term variability may in fact be common and thus can be used to learn about outflow characteristics and contributions to quasar/host-galaxy feedback scenarios.

A. P. Sloan Jr. and leadership

Directory of Open Access Journals (Sweden)

Paul Marinescu

2014-05-01

Full Text Available Organizing the manufacturing processes constituted probably the most difficult challenge in the American automotive industry in the 1920s. A. P. Sloan Jr. was one of the greatest captains of industry and shaped General Motors Corporation into the largest automotive manufacturer of the world. His creative approach on how to mix a degree of decentralized responsibility with centralized control remains a useful example for every corporate leader. The aim of our paper is to emphasize the contribution of Sloan Jr. to the development of leadership. The methodological approach is literature review.

First experience with digital radiography

International Nuclear Information System (INIS)

Buchmann, F.

1987-01-01

The digital radiogram is explained, its advantages being the various possibilities of image processing, loss-free transmission, recording and storage capabilities, and in special cases, prompt availability of processed images. Digital subtraction angiography (DSA) and the high-resolution method of digital, luminescent radiography, which replaced the conventional film-foil radiography, are explained as the first developments for the introduction of digital radiography, which today already is an applicable technique. (orig./MG) [de

The Sloan Digital Sky Survey Quasar Lens Search. IV. Statistical Lens Sample from the Fifth Data Release

Energy Technology Data Exchange (ETDEWEB)

Inada, Naohisa; /Wako, RIKEN /Tokyo U., ICEPP; Oguri, Masamune; /Natl. Astron. Observ. of Japan /Stanford U., Phys. Dept.; Shin, Min-Su; /Michigan U. /Princeton U. Observ.; Kayo, Issha; /Tokyo U., ICRR; Strauss, Michael A.; /Princeton U. Observ.; Hennawi, Joseph F.; /UC, Berkeley /Heidelberg, Max Planck Inst. Astron.; Morokuma, Tomoki; /Natl. Astron. Observ. of Japan; Becker, Robert H.; /LLNL, Livermore /UC, Davis; White, Richard L.; /Baltimore, Space Telescope Sci.; Kochanek, Christopher S.; /Ohio State U.; Gregg, Michael D.; /LLNL, Livermore /UC, Davis /Exeter U.

2010-05-01

We present the second report of our systematic search for strongly lensed quasars from the data of the Sloan Digital Sky Survey (SDSS). From extensive follow-up observations of 136 candidate objects, we find 36 lenses in the full sample of 77,429 spectroscopically confirmed quasars in the SDSS Data Release 5. We then define a complete sample of 19 lenses, including 11 from our previous search in the SDSS Data Release 3, from the sample of 36,287 quasars with i < 19.1 in the redshift range 0.6 < z < 2.2, where we require the lenses to have image separations of 1 < {theta} < 20 and i-band magnitude differences between the two images smaller than 1.25 mag. Among the 19 lensed quasars, 3 have quadruple-image configurations, while the remaining 16 show double images. This lens sample constrains the cosmological constant to be {Omega}{sub {Lambda}} = 0.84{sub -0.08}{sup +0.06}(stat.){sub -0.07}{sup + 0.09}(syst.) assuming a flat universe, which is in good agreement with other cosmological observations. We also report the discoveries of 7 binary quasars with separations ranging from 1.1 to 16.6, which are identified in the course of our lens survey. This study concludes the construction of our statistical lens sample in the full SDSS-I data set.

CHROMOSPHERIC VARIABILITY IN SLOAN DIGITAL SKY SURVEY M DWARFS. II. SHORT-TIMESCALE Hα VARIABILITY

International Nuclear Information System (INIS)

Kruse, E. A.; Berger, E.; Laskar, T.; Knapp, G. R.; Gunn, J. E.; Loomis, C. P.; Lupton, R. H.; Schlegel, D. J.

2010-01-01

We present the first comprehensive study of short-timescale chromospheric Hα variability in M dwarfs using the individual 15 minute spectroscopic exposures for 52, 392 objects from the Sloan Digital Sky Survey. Our sample contains about 10 3 -10 4 objects per spectral type bin in the range M0-M9, with a typical number of three exposures per object (ranging up to a maximum of 30 exposures). Using this extensive data set, we find that about 16% of the sources exhibit Hα emission in at least one exposure, and of those about 45% exhibit Hα emission in all of the available exposures. As in previous studies of Hα activity (L Hα /L bol ), we find a rapid increase in the fraction of active objects from M0-M6. However, we find a subsequent decline in later spectral types that we attribute to our use of the individual spectra. Similarly, we find saturated activity at a level of L Hα /L bol ∼ 10 -3.6 for spectral types M0-M5 followed by a decline to about 10 -4.3 in the range M7-M9. Within the sample of objects with Hα emission, only 26% are consistent with non-variable emission, independent of spectral type. The Hα variability, quantified in terms of the ratio of maximum to minimum Hα equivalent width (R EW ), exhibits a rapid rise from M0 to M5, followed by a plateau and a possible decline in M9 objects. In particular, variability with R EW ∼> 10 is only observed in objects later than M5, and survival analysis indicates a probability of ∼ EW values for M0-M4 and M5-M9 are drawn from the same distribution. We further find that for an exponential distribution, the R EW values follow N(R EW ) ∝ exp[ - (R EW - 1)/2.3] for M0-M4 and ∝exp[ - (R EW - 1)/2.9] for M5-M9. Finally, comparing objects with persistent and intermittent Hα emission, we find that the latter exhibit greater variability. Based on these results, we conclude that Hα variability in M dwarfs on timescales of 15 minutes to 1 hr increases with later spectral type, and that the variability is

Counts-in-Cylinders in the Sloan Digital Sky Survey with Comparisons to N-Body

Energy Technology Data Exchange (ETDEWEB)

Berrier, Heather D.; Barton, Elizabeth J.; /UC, Irvine; Berrier, Joel C.; /Arkansas U.; Bullock, James S.; /UC, Irvine; Zentner, Andrew R.; /Pittsburgh U.; Wechsler, Risa H. /KIPAC, Menlo Park /SLAC

2010-12-16

Environmental statistics provide a necessary means of comparing the properties of galaxies in different environments and a vital test of models of galaxy formation within the prevailing, hierarchical cosmological model. We explore counts-in-cylinders, a common statistic defined as the number of companions of a particular galaxy found within a given projected radius and redshift interval. Galaxy distributions with the same two-point correlation functions do not necessarily have the same companion count distributions. We use this statistic to examine the environments of galaxies in the Sloan Digital Sky Survey, Data Release 4. We also make preliminary comparisons to four models for the spatial distributions of galaxies, based on N-body simulations, and data from SDSS DR4 to study the utility of the counts-in-cylinders statistic. There is a very large scatter between the number of companions a galaxy has and the mass of its parent dark matter halo and the halo occupation, limiting the utility of this statistic for certain kinds of environmental studies. We also show that prevalent, empirical models of galaxy clustering that match observed two- and three-point clustering statistics well fail to reproduce some aspects of the observed distribution of counts-in-cylinders on 1, 3 and 6-h{sup -1}Mpc scales. All models that we explore underpredict the fraction of galaxies with few or no companions in 3 and 6-h{sup -1} Mpc cylinders. Roughly 7% of galaxies in the real universe are significantly more isolated within a 6 h{sup -1} Mpc cylinder than the galaxies in any of the models we use. Simple, phenomenological models that map galaxies to dark matter halos fail to reproduce high-order clustering statistics in low-density environments.

PERIODIC VARIABILITY OF LOW-MASS STARS IN SLOAN DIGITAL SKY SURVEY STRIPE 82

International Nuclear Information System (INIS)

Becker, A. C.; Hawley, S. L.; Ivezic, Z.; Kowalski, A. F.; Sesar, B.; Bochanski, J. J.; West, A. A.

2011-01-01

We present a catalog of periodic stellar variability in the 'Stripe 82' region of the Sloan Digital Sky Survey. After aggregating and re-calibrating catalog-level data from the survey, we ran a period-finding algorithm (Supersmoother) on all point-source light curves. We used color selection to identify systems that are likely to contain low-mass stars, in particular M dwarfs and white dwarfs. In total, we found 207 candidates, the vast majority of which appear to be in eclipsing binary systems. The catalog described in this paper includes 42 candidate M dwarf/white dwarf pairs, four white dwarf pairs, 59 systems whose colors indicate they are composed of two M dwarfs and whose light-curve shapes suggest they are in detached eclipsing binaries, and 28 M dwarf systems whose light-curve shapes suggest they are in contact binaries. We find no detached systems with periods longer than 3 days, thus the majority of our sources are likely to have experienced orbital spin-up and enhanced magnetic activity. Indeed, 26 of 27 M dwarf systems that we have spectra for show signs of chromospheric magnetic activity, far higher than the 24% seen in field stars of the same spectral type. We also find binaries composed of stars that bracket the expected boundary between partially and fully convective interiors, which will allow the measurement of the stellar mass-radius relationship across this transition. The majority of our contact systems have short orbital periods, with small variance (0.02 days) in the sample near the observed cutoff of 0.22 days. The accumulation of these stars at short orbital period suggests that the process of angular momentum loss, leading to period evolution, becomes less efficient at short periods. These short-period systems are in a novel regime for studying the effects of orbital spin-up and enhanced magnetic activity, which are thought to be the source of discrepancies between mass-radius predictions and measurements of these properties in eclipsing

Eclipsing damped Lyα systems in the Sloan Digital Sky Survey Data Release 12★

Science.gov (United States)

Fathivavsari, H.; Petitjean, P.; Jamialahmadi, N.; Khosroshahi, H. G.; Rahmani, H.; Finley, H.; Noterdaeme, P.; Pâris, I.; Srianand, R.

2018-04-01

We present the results of our automatic search for proximate damped Lyα absorption (PDLA) systems in the quasar spectra from the Sloan Digital Sky Survey Data Release 12. We constrain our search to those PDLAs lying within 1500 km s-1 from the quasar to make sure that the broad DLA absorption trough masks most of the strong Lyα emission from the broad line region (BLR) of the quasar. When the Lyα emission from the BLR is blocked by these so-called eclipsing DLAs, narrow Lyα emission from the host galaxy could be revealed as a narrow emission line (NEL) in the DLA trough. We define a statistical sample of 399 eclipsing DLAs with log N(H I) ≥ 21.10. We divide our statistical sample into three subsamples based on the strength of the NEL detected in the DLA trough. By studying the stacked spectra of these subsamples, we found that absorption from high ionization species are stronger in DLAs with stronger NEL in their absorption core. Moreover, absorption from the excited states of species like Si II are also stronger in DLAs with stronger NEL. We also found no correlation between the luminosity of the Lyα NEL and the quasar luminosity. These observations are consistent with a scenario in which the DLAs with stronger NEL are denser and physically closer to the quasar. We propose that these eclipsing DLAs could be the product of the interaction between infalling and outflowing gas. High resolution spectroscopic observation would be needed to shed some light on the nature of these eclipsing DLAs.

We’re Working On It: Transferring the Sloan Digital Sky Survey from Laboratory to Library

Directory of Open Access Journals (Sweden)

Ashley E. Sands

2014-10-01

Full Text Available This article reports on the transfer of a massive scientific dataset from a national laboratory to a university library, and from one kind of workforce to another. We use the transfer of the Sloan Digital Sky Survey (SDSS archive to examine the emergence of a new workforce for scientific research data management. Many individuals with diverse educational backgrounds and domain experience are involved in SDSS data management: domain scientists, computer scientists, software and systems engineers, programmers, and librarians. These types of positions have been described using terms such as research technologist, data scientist, e-science professional, data curator, and more. The findings reported here are based on semi-structured interviews, ethnographic participant observation, and archival studies from 2011-2013. The library staff conducting the data storage and archiving of the SDSS archive faced two performance problems. The preservation specialist and the system administrator worked together closely to discover and implement solutions to the slow data transfer and verification processes. The team overcame these slow-downs by problem solving, working in a team, and writing code. The library team lacked the astronomy domain knowledge necessary to meet some of their preservation and curation goals. The case study reveals the variety of expertise, experience, and individuals essential to the SDSS data management process. A variety of backgrounds and educational histories emerge in the data managers studied. Teamwork is necessary to bring disparate expertise together, especially between those with technical and domain education. The findings have implications for data management education, policy and relevant stakeholders. This article is part of continuing research on Knowledge Infrastructures.

GREEN PEA GALAXIES AND COHORTS: LUMINOUS COMPACT EMISSION-LINE GALAXIES IN THE SLOAN DIGITAL SKY SURVEY

International Nuclear Information System (INIS)

Izotov, Yuri I.; Guseva, Natalia G.; Thuan, Trinh X.

2011-01-01

We present a large sample of 803 star-forming luminous compact galaxies (LCGs) in the redshift range z = 0.02-0.63, selected from Data Release 7 of the Sloan Digital Sky Survey (SDSS). The global properties of these galaxies are similar to those of the so-called green pea star-forming galaxies in the redshift range z = 0.112-0.360 and selected from the SDSS on the basis of their green color and compact structure. In contrast to green pea galaxies, our LCGs are selected on the basis of both their spectroscopic and photometric properties, resulting in a ∼10 times larger sample, with galaxies spanning a redshift range ∼>2 times larger. We find that the oxygen abundances and the heavy element abundance ratios in LCGs do not differ from those of nearby low-metallicity blue compact dwarf galaxies. The median stellar mass of LCGs is ∼10 9 M sun . However, for galaxies with high EW(Hβ), ≥ 100 A, it is only ∼7 x 10 8 M sun . The star formation rate in LCGs varies in the large range of 0.7-60 M sun yr -1 , with a median value of ∼4 M sun yr -1 , a factor of ∼3 lower than in high-redshift star-forming galaxies at z ∼> 3. The specific star formation rates in LCGs are extremely high and vary in the range ∼10 -9 -10 -7 yr -1 , comparable to those derived in high-redshift galaxies.

A SURVEY FOR NEW MEMBERS OF THE TAURUS STAR-FORMING REGION WITH THE SLOAN DIGITAL SKY SURVEY

International Nuclear Information System (INIS)

Luhman, K. L.; Mamajek, E. E.; Shukla, S. J.; Loutrel, N. P.

2017-01-01

Previous studies have found that ∼1 deg 2 fields surrounding the stellar aggregates in the Taurus star-forming region exhibit a surplus of solar-mass stars relative to denser clusters like IC 348 and the Orion Nebula Cluster. To test whether this difference reflects mass segregation in Taurus or a variation in the initial mass function, we have performed a survey for members of Taurus across a large field (∼40 deg 2 ) that was imaged by the Sloan Digital Sky Survey (SDSS). We obtained optical and near-infrared spectra of candidate members identified with those images and the Two Micron All Sky Survey, as well as miscellaneous candidates that were selected with several other diagnostics of membership. We have classified 22 of the candidates as new members of Taurus, which includes one of the coolest known members (M9.75). Our updated census of members within the SDSS field shows a surplus of solar-mass stars relative to clusters, although it is less pronounced than in the smaller fields toward the stellar aggregates that were surveyed for previously measured mass functions in Taurus. In addition to spectra of our new members, we include in our study near-IR spectra of roughly half of the known members of Taurus, which are used to refine their spectral types and extinctions. We also present an updated set of near-IR standard spectra for classifying young stars and brown dwarfs at M and L types.

AN IMPROVED SPECTROSCOPIC ANALYSIS OF DA WHITE DWARFS FROM THE SLOAN DIGITAL SKY SURVEY DATA RELEASE 4

International Nuclear Information System (INIS)

Tremblay, P.-E.; Bergeron, P.; Gianninas, A.

2011-01-01

We present an improved spectroscopic and photometric analysis of hydrogen-line DA white dwarfs from the Sloan Digital Sky Survey Data Release 4 (SDSS DR4) based on model atmospheres that include improved Stark broadening profiles with non-ideal gas effects. We also perform a careful visual inspection of all spectroscopic fits with high signal-to-noise ratios (S/Ns > 12) and present improved atmospheric parameters (T eff and log g) for each white dwarf. Through a comparison of spectroscopic and photometric temperatures, we report the discovery of 35 DA+DB/DC double degenerate candidates and two helium-rich DA stars. We also determine that a cutoff at S/N = 15 optimizes the size and quality of the sample for computing the mean mass of DA white dwarfs, for which we report a value of 0.613 M sun . We compare our results to previous analyses of the SDSS DR4 and find a good agreement if we account for the shift produced by the improved Stark profiles. Finally, the properties of DA white dwarfs in the SDSS are weighed against those of the Villanova White Dwarf Catalog sample of Gianninas et al. We find systematically lower masses (by about 3% on average), a difference that we trace back to the data reduction procedure of the SDSS. We conclude that a better understanding of these differences will be important to determine the absolute temperature scale and mean mass of DA white dwarfs.

A SURVEY FOR NEW MEMBERS OF THE TAURUS STAR-FORMING REGION WITH THE SLOAN DIGITAL SKY SURVEY

Energy Technology Data Exchange (ETDEWEB)

Luhman, K. L. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Mamajek, E. E. [Department of Physics and Astronomy, The University of Rochester, Rochester, NY 14627 (United States); Shukla, S. J. [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom); Loutrel, N. P., E-mail: kluhman@astro.psu.edu [eXtreme Gravity Institute, Department of Physics, Montana State University, Bozeman, MT 59715 (United States)

2017-01-01

Previous studies have found that ∼1 deg{sup 2} fields surrounding the stellar aggregates in the Taurus star-forming region exhibit a surplus of solar-mass stars relative to denser clusters like IC 348 and the Orion Nebula Cluster. To test whether this difference reflects mass segregation in Taurus or a variation in the initial mass function, we have performed a survey for members of Taurus across a large field (∼40 deg{sup 2}) that was imaged by the Sloan Digital Sky Survey (SDSS). We obtained optical and near-infrared spectra of candidate members identified with those images and the Two Micron All Sky Survey, as well as miscellaneous candidates that were selected with several other diagnostics of membership. We have classified 22 of the candidates as new members of Taurus, which includes one of the coolest known members (M9.75). Our updated census of members within the SDSS field shows a surplus of solar-mass stars relative to clusters, although it is less pronounced than in the smaller fields toward the stellar aggregates that were surveyed for previously measured mass functions in Taurus. In addition to spectra of our new members, we include in our study near-IR spectra of roughly half of the known members of Taurus, which are used to refine their spectral types and extinctions. We also present an updated set of near-IR standard spectra for classifying young stars and brown dwarfs at M and L types.

THE X-RAY PROPERTIES OF THE OPTICALLY BRIGHTEST MINI-BAL QUASARS FROM THE SLOAN DIGITAL SKY SURVEY

International Nuclear Information System (INIS)

Wu Jianfeng; Brandt, W. N.; Comins, M. L.; Garmire, Gordon P.; Schneider, Donald P.; Gibson, Robert R.; Shemmer, Ohad

2010-01-01

We have compiled a sample of 14 of the optically brightest radio-quiet quasars (m i ≤ 17.5 and z ≥ 1.9) in the Sloan Digital Sky Survey Data Release 5 quasar catalog that have C IV mini-broad absorption lines (mini-BALs) present in their spectra. X-ray data for 12 of the objects were obtained via a Chandra snapshot survey using ACIS-S, while data for the other two quasars were obtained from archival XMM-Newton observations. Joint X-ray spectral analysis shows that the mini-BAL quasars have a similar average power-law photon index (Γ ∼ 1.9) and level of intrinsic absorption (N H ∼ 21 cm -2 ) as non-BMB (neither BAL nor mini-BAL) quasars. Mini-BAL quasars are more similar to non-BMB quasars than to BAL quasars in their distribution of relative X-ray brightness (assessed with Δα ox ). Relative colors indicate mild dust reddening in the optical spectra of mini-BAL quasars. Significant correlations between Δα ox and UV absorption properties are confirmed for a sample of 56 sources combining mini-BAL and BAL quasars with high signal-to-noise ratio rest-frame UV spectra, which generally supports models in which X-ray absorption is important in enabling driving of the UV absorption-line wind. We also propose alternative parameterizations of the UV absorption properties of mini-BAL and BAL quasars, which may better describe the broad absorption troughs in some respects.

TESTING STELLAR POPULATION SYNTHESIS MODELS WITH SLOAN DIGITAL SKY SURVEY COLORS OF M31's GLOBULAR CLUSTERS

International Nuclear Information System (INIS)

Peacock, Mark B.; Zepf, Stephen E.; Maccarone, Thomas J.; Kundu, Arunav

2011-01-01

Accurate stellar population synthesis models are vital in understanding the properties and formation histories of galaxies. In order to calibrate and test the reliability of these models, they are often compared with observations of star clusters. However, relatively little work has compared these models in the ugriz filters, despite the recent widespread use of this filter set. In this paper, we compare the integrated colors of globular clusters in the Sloan Digital Sky Survey (SDSS) with those predicted from commonly used simple stellar population (SSP) models. The colors are based on SDSS observations of M31's clusters and provide the largest population of star clusters with accurate photometry available from the survey. As such, it is a unique sample with which to compare SSP models with SDSS observations. From this work, we identify a significant offset between the SSP models and the clusters' g - r colors, with the models predicting colors which are too red by g - r ∼ 0.1. This finding is consistent with previous observations of luminous red galaxies in the SDSS, which show a similar discrepancy. The identification of this offset in globular clusters suggests that it is very unlikely to be due to a minority population of young stars. The recently updated SSP model of Maraston and Stroembaeck better represents the observed g - r colors. This model is based on the empirical MILES stellar library, rather than theoretical libraries, suggesting an explanation for the g - r discrepancy.

A PUBLIC CATALOG OF STELLAR MASSES, STAR FORMATION AND METALLICITY HISTORIES, AND DUST CONTENT FROM THE SLOAN DIGITAL SKY SURVEY USING VESPA

International Nuclear Information System (INIS)

Tojeiro, Rita; Wilkins, Stephen; Heavens, Alan F.; Panter, Ben; Jimenez, Raul

2009-01-01

We applied the VESPA algorithm to the Sloan Digital Sky Survey final data release of the Main Galaxies and Luminous Red Galaxies samples. The result is a catalog of stellar masses, detailed star formation and metallicity histories and dust content of nearly 800,000 galaxies. We make the catalog public via a T-SQL database, which is described in detail in this paper. We present the results using a range of stellar population and dust models, and will continue to update the catalog as new and improved models are made public. We also present a brief exploration of the catalog, and show that the quantities derived are robust: luminous red galaxies can be described by one to three populations, whereas a main galaxy sample galaxy needs on average two to five; red galaxies are older and less dusty; the dust values we recover are well correlated with measured Balmer decrements and star formation rates are also in agreement with previous measurements. We find that whereas some derived quantities are robust to the choice of modelling, many are still not.

COUNTS-IN-CYLINDERS IN THE SLOAN DIGITAL SKY SURVEY WITH COMPARISONS TO N-BODY SIMULATIONS

International Nuclear Information System (INIS)

Berrier, Heather D.; Barton, Elizabeth J.; Bullock, James S.; Berrier, Joel C.; Zentner, Andrew R.; Wechsler, Risa H.

2011-01-01

Environmental statistics provide a necessary means of comparing the properties of galaxies in different environments, and a vital test of models of galaxy formation within the prevailing hierarchical cosmological model. We explore counts-in-cylinders, a common statistic defined as the number of companions of a particular galaxy found within a given projected radius and redshift interval. Galaxy distributions with the same two-point correlation functions do not necessarily have the same companion count distributions. We use this statistic to examine the environments of galaxies in the Sloan Digital Sky Survey Data Release 4 (SDSS DR4). We also make preliminary comparisons to four models for the spatial distributions of galaxies, based on N-body simulations and data from SDSS DR4, to study the utility of the counts-in-cylinders statistic. There is a very large scatter between the number of companions a galaxy has and the mass of its parent dark matter halo and the halo occupation, limiting the utility of this statistic for certain kinds of environmental studies. We also show that prevalent empirical models of galaxy clustering, that match observed two- and three-point clustering statistics well, fail to reproduce some aspects of the observed distribution of counts-in-cylinders on 1, 3, and 6 h -1 Mpc scales. All models that we explore underpredict the fraction of galaxies with few or no companions in 3 and 6 h -1 Mpc cylinders. Roughly 7% of galaxies in the real universe are significantly more isolated within a 6 h -1 Mpc cylinder than the galaxies in any of the models we use. Simple phenomenological models that map galaxies to dark matter halos fail to reproduce high-order clustering statistics in low-density environments.

Erratum: Sloan Magnitudes for the Brightest Stars

Science.gov (United States)

Mallama, A.

2018-06-01

In the article "Sloan Magnitudes for the Brightest Stars" (JAAVSO, 2014, 42, 443), Equation 3 in section A.1. of the Appendix is incorrect; the coefficient of ((R-I) - C1) should be 0.935, rather than 0.953. The mean differences between the new and old results are 0.00 in all cases, and the standard deviations are all 0.00 or 0.01, which is less than the photometric uncertainties of the Johnson or Sloan values. A revised version of the catalog has been published at https://arxiv.org/abs/1805.09324. The revision is proposed as a bright star extension to the APASS database.

X-RAY-EMITTING STARS IDENTIFIED FROM THE ROSAT ALL-SKY SURVEY AND THE SLOAN DIGITAL SKY SURVEY

International Nuclear Information System (INIS)

Agueeros, Marcel A.; Newsom, Emily R.; Anderson, Scott F.; Hawley, Suzanne L.; Silvestri, Nicole M.; Szkody, Paula; Covey, Kevin R.; Posselt, Bettina; Margon, Bruce; Voges, Wolfgang

2009-01-01

The ROSAT All-Sky Survey (RASS) was the first imaging X-ray survey of the entire sky. Combining the RASS Bright and Faint Source Catalogs yields an average of about three X-ray sources per square degree. However, while X-ray source counterparts are known to range from distant quasars to nearby M dwarfs, the RASS data alone are often insufficient to determine the nature of an X-ray source. As a result, large-scale follow-up programs are required to construct samples of known X-ray emitters. We use optical data produced by the Sloan Digital Sky Survey (SDSS) to identify 709 stellar X-ray emitters cataloged in the RASS and falling within the SDSS Data Release 1 footprint. Most of these are bright stars with coronal X-ray emission unsuitable for SDSS spectroscopy, which is designed for fainter objects (g > 15 [mag]). Instead, we use SDSS photometry, correlations with the Two Micron All Sky Survey and other catalogs, and spectroscopy from the Apache Point Observatory 3.5 m telescope to identify these stellar X-ray counterparts. Our sample of 707 X-ray-emitting F, G, K, and M stars is one of the largest X-ray-selected samples of such stars. We derive distances to these stars using photometric parallax relations appropriate for dwarfs on the main sequence, and use these distances to calculate L X . We also identify a previously unknown cataclysmic variable (CV) as a RASS counterpart. Separately, we use correlations of the RASS and the SDSS spectroscopic catalogs of CVs and white dwarfs (WDs) to study the properties of these rarer X-ray-emitting stars. We examine the relationship between (f X /f g ) and the equivalent width of the Hβ emission line for 46 X-ray-emitting CVs and discuss tentative classifications for a subset based on these quantities. We identify 17 new X-ray-emitting DA (hydrogen) WDs, of which three are newly identified WDs. We report on follow-up observations of three candidate cool X-ray-emitting WDs (one DA and two DB (helium) WDs); we have not

Cataclysmic Variables from SDSS I. The First Results

OpenAIRE

Szkody, P.; Anderson, S. F.; Agueros, M.; Covarrubias, R.; Bentz, M.; Hawley, S.; Margon, B.; Voges, W.; Henden, A.; Knapp, G. R.; Berk, D. E. Vanden; Rest, A.; Miknaitis, G.; Magnier, E.; Brinkmann, J.

2001-01-01

The commissioning year of the Sloan Digital Sky Survey has demonstrated that many cataclysmic variables have been missed in previous surveys with brighter limits. We report the identification of 22 cataclysmic variables, of which 19 are new discoveries and 3 are known systems (SW UMa, BH Lyn and Vir4). A compendium of positions, colors and characteristics of these systems obtained from the SDSS photometry and spectroscopy is presented along with data obtained during follow-up studies with the...

Digital mammography screening: average glandular dose and first performance parameters

International Nuclear Information System (INIS)

Weigel, S.; Girnus, R.; Czwoydzinski, J.; Heindel, W.; Decker, T.; Spital, S.

2007-01-01

Purpose: The Radiation Protection Commission demanded structured implementation of digital mammography screening in Germany. The main requirements were the installation of digital reference centers and separate evaluation of the fully digitized screening units. Digital mammography screening must meet the quality standards of the European guidelines and must be compared to analog screening results. We analyzed early surrogate indicators of effective screening and dosage levels for the first German digital screening unit in a routine setting after the first half of the initial screening round. Materials and Methods: We used three digital mammography screening units (one full-field digital scanner [DR] and two computed radiography systems [CR]). Each system has been proven to fulfill the requirements of the National and European guidelines. The radiation exposure levels, the medical workflow and the histological results were documented in a central electronic screening record. Results: In the first year 11,413 women were screened (participation rate 57.5 %). The parenchymal dosages for the three mammographic X-ray systems, averaged for the different breast sizes, were 0.7 (DR), 1.3 (CR), 1.5 (CR) mGy. 7 % of the screened women needed to undergo further examinations. The total number of screen-detected cancers was 129 (detection rate 1.1 %). 21 % of the carcinomas were classified as ductal carcinomas in situ, 40 % of the invasive carcinomas had a histological size ≤ 10 mm and 61 % < 15 mm. The frequency distribution of pT-categories of screen-detected cancer was as follows: pTis 20.9 %, pT1 61.2 %, pT2 14.7 %, pT3 2.3 %, pT4 0.8 %. 73 % of the invasive carcinomas were node-negative. (orig.)

The Sloan-C Pillars: Towards a Balanced Approach to Measuring Organizational Learning

Science.gov (United States)

Yeo, Kee Meng; Mayadas, A. Frank

2010-01-01

The Sloan Pillars have set the standard for university-wide online learning program assessment for more than a dozen years. In this paper, the authors propose the extension of the Pillars to corporate e-learning, offering an alternative to traditional enterprise learning assessments. Claiming that conventional methods stress individual courses or…

The First Digit 1

Indian Academy of Sciences (India)

IAS Admin

RESONANCE | December 2013. GENERAL | ARTICLE. The First Digit 1. Tanya Kaushal Srivastava. Keywords. Random numbers, unpredict- able, equidistribution, Weyl cri- terion, absorptive property. Tanya Kaushal Srivastava is a BS-MS student at the. Department of Mathemat- ics, IISER Mohali and is a. KVPY fellow.

XMM-NEWTON/SLOAN DIGITAL SKY SURVEY: STAR FORMATION EFFICIENCY IN GALAXY CLUSTERS AND CONSTRAINTS ON THE MATTER-DENSITY PARAMETER

Energy Technology Data Exchange (ETDEWEB)

Lagana, Tatiana F. [Universidade de Sao Paulo, Instituto de Astronomia, Geofisica e Ciencias Atmosfericas, Departamento de Astronomia, Cidade Universitaria, CEP:05508-090, Sao Paulo, SP (Brazil); Zhang Yuying; Reiprich, Thomas H.; Schneider, Peter [Argelander-Institut fuer Astronomie, Universitaet Bonn, 53121 Bonn (Germany)

2011-12-10

It is believed that the global baryon content of clusters of galaxies is representative of the matter distribution of the universe, and can, therefore, be used to reliably determine the matter-density parameter {Omega}{sub m}. This assumption is challenged by the growing evidence from optical and X-ray observations that the total baryon mass fraction increases toward rich clusters. In this context, we investigate the dependence of stellar and total baryon mass fractions as a function of mass. To do so, we used a subsample of 19 clusters extracted from the X-ray flux-limited sample HIFLUGCS that have available Sloan Digital Sky Survey Data Release 7 data. From the optical analysis we derived the stellar masses. Using XMM-Newton we derived the gas masses. Then, adopting a scaling relation we estimate the total masses. Adding the gas and the stellar mass fractions we obtain the total baryonic content that we find to increase with cluster mass, reaching seven-year Wilkinson Microwave Anisotropy Probe (WMAP7) prediction for clusters with M{sub 500} = 1.6 Multiplication-Sign 10{sup 15} M{sub Sun }. We observe a decrease of the stellar mass fraction (from 4.5% to {approx}1.0%) with increasing total mass where our findings for the stellar mass fraction agree with previous studies. This result suggests a difference in the number of stars formed per unit of halo mass, though with a large scatter for low-mass systems. That is, the efficiency of star formation varies on a cluster scale that lower mass systems are likely to have higher star formation efficiencies. It follows immediately that the dependence of the stellar mass fraction on total mass results in an increase of the mass-to-light ratio from lower to higher mass systems. We also discuss the consequences of these results in the context of determining the cosmic matter-density parameter {Omega}{sub m}.

AUTOMATED UNSUPERVISED CLASSIFICATION OF THE SLOAN DIGITAL SKY SURVEY STELLAR SPECTRA USING k-MEANS CLUSTERING

Energy Technology Data Exchange (ETDEWEB)

Sanchez Almeida, J.; Allende Prieto, C., E-mail: jos@iac.es, E-mail: callende@iac.es [Instituto de Astrofisica de Canarias, E-38205 La Laguna, Tenerife (Spain)

2013-01-20

Large spectroscopic surveys require automated methods of analysis. This paper explores the use of k-means clustering as a tool for automated unsupervised classification of massive stellar spectral catalogs. The classification criteria are defined by the data and the algorithm, with no prior physical framework. We work with a representative set of stellar spectra associated with the Sloan Digital Sky Survey (SDSS) SEGUE and SEGUE-2 programs, which consists of 173,390 spectra from 3800 to 9200 A sampled on 3849 wavelengths. We classify the original spectra as well as the spectra with the continuum removed. The second set only contains spectral lines, and it is less dependent on uncertainties of the flux calibration. The classification of the spectra with continuum renders 16 major classes. Roughly speaking, stars are split according to their colors, with enough finesse to distinguish dwarfs from giants of the same effective temperature, but with difficulties to separate stars with different metallicities. There are classes corresponding to particular MK types, intrinsically blue stars, dust-reddened, stellar systems, and also classes collecting faulty spectra. Overall, there is no one-to-one correspondence between the classes we derive and the MK types. The classification of spectra without continuum renders 13 classes, the color separation is not so sharp, but it distinguishes stars of the same effective temperature and different metallicities. Some classes thus obtained present a fairly small range of physical parameters (200 K in effective temperature, 0.25 dex in surface gravity, and 0.35 dex in metallicity), so that the classification can be used to estimate the main physical parameters of some stars at a minimum computational cost. We also analyze the outliers of the classification. Most of them turn out to be failures of the reduction pipeline, but there are also high redshift QSOs, multiple stellar systems, dust-reddened stars, galaxies, and, finally, odd

THE INTRINSIC EDDINGTON RATIO DISTRIBUTION OF ACTIVE GALACTIC NUCLEI IN STAR-FORMING GALAXIES FROM THE SLOAN DIGITAL SKY SURVEY

Energy Technology Data Exchange (ETDEWEB)

Jones, Mackenzie L.; Hickox, Ryan C.; Black, Christine S.; Hainline, Kevin N.; DiPompeo, Michael A. [Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States); Goulding, Andy D. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

2016-07-20

An important question in extragalactic astronomy concerns the distribution of black hole accretion rates of active galactic nuclei (AGNs). Based on observations at X-ray wavelengths, the observed Eddington ratio distribution appears as a power law, while optical studies have often yielded a lognormal distribution. There is increasing evidence that these observed discrepancies may be due to contamination by star formation and other selection effects. Using a sample of galaxies from the Sloan Digital Sky Survey Data Release 7, we test whether or not an intrinsic Eddington ratio distribution that takes the form of a Schechter function is consistent with previous work suggesting that young galaxies in optical surveys have an observed lognormal Eddington ratio distribution. We simulate the optical emission line properties of a population of galaxies and AGNs using a broad, instantaneous luminosity distribution described by a Schechter function near the Eddington limit. This simulated AGN population is then compared to observed galaxies via their positions on an emission line excitation diagram and Eddington ratio distributions. We present an improved method for extracting the AGN distribution using BPT diagnostics that allows us to probe over one order of magnitude lower in Eddington ratio, counteracting the effects of dilution by star formation. We conclude that for optically selected AGNs in young galaxies, the intrinsic Eddington ratio distribution is consistent with a possibly universal, broad power law with an exponential cutoff, as this distribution is observed in old, optically selected galaxies and X-rays.

Component masses of young, wide, non-magnetic white dwarf binaries in the Sloan Digital Sky Survey Data Release 7

Science.gov (United States)

Baxter, R. B.; Dobbie, P. D.; Parker, Q. A.; Casewell, S. L.; Lodieu, N.; Burleigh, M. R.; Lawrie, K. A.; Külebi, B.; Koester, D.; Holland, B. R.

2014-06-01

We present a spectroscopic component analysis of 18 candidate young, wide, non-magnetic, double-degenerate binaries identified from a search of the Sloan Digital Sky Survey Data Release 7 (DR7). All but two pairings are likely to be physical systems. We show SDSS J084952.47+471247.7 + SDSS J084952.87+471249.4 to be a wide DA + DB binary, only the second identified to date. Combining our measurements for the components of 16 new binaries with results for three similar, previously known systems within the DR7, we have constructed a mass distribution for the largest sample to date (38) of white dwarfs in young, wide, non-magnetic, double-degenerate pairings. This is broadly similar in form to that of the isolated field population with a substantial peak around M ˜ 0.6 M⊙. We identify an excess of ultramassive white dwarfs and attribute this to the primordial separation distribution of their progenitor systems peaking at relatively larger values and the greater expansion of their binary orbits during the final stages of stellar evolution. We exploit this mass distribution to probe the origins of unusual types of degenerates, confirming a mild preference for the progenitor systems of high-field-magnetic white dwarfs, at least within these binaries, to be associated with early-type stars. Additionally, we consider the 19 systems in the context of the stellar initial mass-final mass relation. None appear to be strongly discordant with current understanding of this relationship.

A SEARCH FOR OXYGEN IN THE LOW-DENSITY Lyα FOREST USING THE SLOAN DIGITAL SKY SURVEY

International Nuclear Information System (INIS)

Pieri, Matthew M.; Frank, Stephan; Mathur, Smita; Weinberg, David H.; York, Donald G.; Oppenheimer, Benjamin D.

2010-01-01

We use 2167 Sloan Digital Sky Survey quasar spectra to search for low-density oxygen in the intergalactic medium (IGM). Oxygen absorption is detected on a pixel-by-pixel basis by its correlation with Lyα forest absorption. We have developed a novel locally calibrated pixel (LCP) search method that uses adjacent regions of the spectrum to calibrate interlopers and spectral artifacts, which would otherwise limit the measurement of O VI absorption. Despite the challenges presented by searching for weak O VI within the Lyα forest in spectra of moderate resolution and signal-to-noise, we find a highly significant detection of absorption by oxygen at 2.7 2 = 80 for nine data points). We interpret our results using synthetic spectra generated from a log-normal density field assuming a mixed quasar-galaxy photoionizing background and that it dominates the ionization fraction of detected O VI. The LCP search data can be fit by a constant metallicity model with [O/H] = -2.15 +0.07 -0.09 but also by models in which low-density regions are unenriched and higher density regions have a higher metallicity. The density-dependent enrichment model by Aguirre et al. is also an acceptable fit. All our successful models have similar mass-weighted oxygen abundance, corresponding to [(O/H) MW ] = -2.45 ± 0.06. This result can be used to find the cosmic oxygen density in the Lyα forest, Ω Oxy,IGM = 1.4(±0.2) x 10 -6 ∼ 3 x 10 -4 Ω b . This is the tightest constraint on the mass-weighted mean oxygen abundance and the cosmic oxygen density in the Lyα forest to date and indicates that it contains ∼16% of the total expected metal production by star formation up to z = 3.

The SDSS-IV in 2015: Report of the Committee on the Participation of Women in the Sloan Digital Sky Survey

Science.gov (United States)

Diamond-Stanic, Aleksandar M.; Lucatello, Sara; Aragon-Salamanca, Alfonso; Cherinka, Brian; Cunha, Katia M. L.; Gillespie, Bruce Andrew; Hagen, Alex; Jones, Amy; Kinemuchi, Karen; Lundgren, Britt; Myers, Adam D.; Roman, Alexandre; Zasowski, Gail; SDSS-IV Collaboration

2016-01-01

Given that many astronomers now participate in large international scientific collaborations, it is important to examine whether these structures foster a healthy scientific climate that is inclusive and diverse. The Committee on the Participation of Women in the Sloan Digital Sky Survey (CPWS) was formed to evaluate the climate and demographics within the SDSS collaboration and to make recommendations for how best to establish the scientific and technical leadership team for SDSS-IV. Building on the work described in Lundgren et al. (2015), the CPWS conducted a demographic survey in Spring 2015 that included questions about career and leadership status, racial / ethnic identity, gender identity, identification with the LGBT community, disability, partnership status, and level of parental education. For example, 71% of survey respondents identify as male and 81% do not identify as a racial or ethnic minority at their current institution. This reflects the under-representation of women and men from minority groups (e.g., people of color in the United States) and women from majority groups (e.g., white women in the United States) in the field of astronomy. We have focused our analysis on the representation of scientists from these groups among the SDSS-IV leadership and the full collaboration. Our goal is to use these quantitative data to track the demographics of SDSS-IV membership and leadership over time as we work to assess and improve the climate of SDSS-IV.

THE REDSHIFT DISTRIBUTION OF GIANT ARCS IN THE SLOAN GIANT ARCS SURVEY

International Nuclear Information System (INIS)

Bayliss, Matthew B.; Gladders, Michael D.; Koester, Benjamin P.; Oguri, Masamune; Hennawi, Joseph F.; Sharon, Keren; Dahle, Haakon

2011-01-01

We measure the redshift distribution of a sample of 28 giant arcs discovered as a part of the Sloan Giant Arcs Survey. Gemini/GMOS-North spectroscopy provides precise redshifts for 24 arcs, and 'redshift desert' constrains for the remaining 4 arcs. This is a direct measurement of the redshift distribution of a uniformly selected sample of bright giant arcs, which is an observable that can be used to inform efforts to predict giant arc statistics. Our primary giant arc sample has a median redshift z = 1.821 and nearly two-thirds of the arcs, 64%, are sources at z ∼> 1.4, indicating that the population of background sources that are strongly lensed into bright giant arcs resides primarily at high redshift. We also analyze the distribution of redshifts for 19 secondary strongly lensed background sources that are not visually apparent in Sloan Digital Sky Survey imaging, but were identified in deeper follow-up imaging of the lensing cluster fields. Our redshift sample for the secondary sources is not spectroscopically complete, but combining it with our primary giant arc sample suggests that a large fraction of all background galaxies that are strongly lensed by foreground clusters reside at z ∼> 1.4. Kolmogorov-Smirnov tests indicate that our well-selected, spectroscopically complete primary giant arc redshift sample can be reproduced with a model distribution that is constructed from a combination of results from studies of strong-lensing clusters in numerical simulations and observational constraints on the galaxy luminosity function.

CALIBRATIONS OF ATMOSPHERIC PARAMETERS OBTAINED FROM THE FIRST YEAR OF SDSS-III APOGEE OBSERVATIONS

Energy Technology Data Exchange (ETDEWEB)

Mészáros, Sz.; Allende Prieto, C. [Instituto de Astrofísica de Canarias (IAC), E-38200 La Laguna, Tenerife (Spain); Holtzman, J. [New Mexico State University, Las Cruces, NM 88003 (United States); García Pérez, A. E.; Chojnowski, S. D.; Hearty, F. R.; Majewski, S. R. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States); Schiavon, R. P. [Astrophysics Research Institute, Liverpool John Moores University, Egerton Wharf, Birkenhead, Wirral CH41 1LD (United Kingdom); Basu, S. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States); Bizyaev, D. [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349-0059 (United States); Chaplin, W. J.; Elsworth, Y. [University of Birmingham, School of Physics and Astronomy, Edgbaston, Birmingham B15 2TT (United Kingdom); Cunha, K. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Epstein, C.; Johnson, J. A. [Department of Astronomy, The Ohio State University, Columbus, OH 43210 (United States); Frinchaboy, P. M. [Texas Christian University, Fort Worth, TX 76129 (United States); García, R. A. [Laboratoire AIM, CEA/DSM-CNRS-Université Paris Diderot, IRFU/SAp, Centre de Saclay, F-91191 Gif-sur-Yvette Cedex (France); Hekker, S. [Astronomical Institute ' ' Anton Pannekoek' ' , University of Amsterdam, Science Park 904, 1098 XH Amsterdam (Netherlands); Kallinger, T. [Institute for Astronomy, University of Vienna, Türkenschanzstrasse 17, A-1180 Vienna (Austria); Koesterke, L. [Texas Advanced Computing Center, University of Texas, Austin, TX 78759 (United States); and others

2013-11-01

The Sloan Digital Sky Survey III (SDSS-III) Apache Point Observatory Galactic Evolution Experiment (APOGEE) is a three-year survey that is collecting 10{sup 5} high-resolution spectra in the near-IR across multiple Galactic populations. To derive stellar parameters and chemical compositions from this massive data set, the APOGEE Stellar Parameters and Chemical Abundances Pipeline (ASPCAP) has been developed. Here, we describe empirical calibrations of stellar parameters presented in the first SDSS-III APOGEE data release (DR10). These calibrations were enabled by observations of 559 stars in 20 globular and open clusters. The cluster observations were supplemented by observations of stars in NASA's Kepler field that have well determined surface gravities from asteroseismic analysis. We discuss the accuracy and precision of the derived stellar parameters, considering especially effective temperature, surface gravity, and metallicity; we also briefly discuss the derived results for the abundances of the α-elements, carbon, and nitrogen. Overall, we find that ASPCAP achieves reasonably accurate results for temperature and metallicity, but suffers from systematic errors in surface gravity. We derive calibration relations that bring the raw ASPCAP results into better agreement with independently determined stellar parameters. The internal scatter of ASPCAP parameters within clusters suggests that metallicities are measured with a precision better than 0.1 dex, effective temperatures better than 150 K, and surface gravities better than 0.2 dex. The understanding provided by the clusters and Kepler giants on the current accuracy and precision will be invaluable for future improvements of the pipeline.

Open Access Forever -- Or Five Years, Whichever Comes First: Progress on Preserving the Digital Scholarly Record

CERN Multimedia

CERN. Geneva

2007-01-01

As the migration of scholarly communication from print to digital continues to progress rapidly, and as Open Access to that research literature and related data becomes more common, the challenges of insuring that the scholarly record remain available over time becomes more urgent. There has been good progress on those challenges in recent years, but many problems remain. The current state of the curation and preservation of digital scholarship over its entire lifecycle will be reviewed, and progress on problems of specific interest to scholarly communication will be examined. The difficulty of curating the digital scholarly record and preserving it for future generations has important implications for the movement to make that record more open and accessible to the world, so this a timely topic for those who are interested in the future of scholarly communication. View Mackensie Smith's biography

Open Access Forever - Or Five Years, Whichever Comes First Progress on Preserving the Digital Scholarly Record

CERN Document Server

CERN. Geneva; Bjørnshauge, Lars

2007-01-01

As the migration of scholarly communication from print to digital continues to progress rapidly, and as Open Access to that research literature and related data becomes more common, the challenges of insuring that the scholarly record remain available over time becomes more urgent. There has been good progress on those challenges in recent years, but many problems remain. The current state of the curation and preservation of digital scholarship over its entire lifecycle will be reviewed, and progress on problems of specific interest to scholarly communication will be examined. The difficulty of curating the digital scholarly record and preserving it for future generations has important implications for the movement to make that record more open and accessible to the world, so this a timely topic for those who are interested in the future of scholarly communication.

75 FR 22423 - Pick-Sloan Missouri Basin Program, Eastern and Western Division Proposed Project Use Power Rate

Science.gov (United States)

2010-04-28

...: Reopening of comment period for review of the Pick-Sloan Missouri Basin Program, Eastern and Western... reopening the comment period for the Pick-Sloan Missouri Basin Program, Eastern and Western Division... DEPARTMENT OF THE INTERIOR Bureau of Reclamation Pick-Sloan Missouri Basin Program, Eastern and...

75 FR 1408 - Pick-Sloan Missouri Basin Program, Eastern and Western Division Proposed Project Use Power Rate

Science.gov (United States)

2010-01-11

... of Proposed Pick-Sloan Missouri Basin Program, Eastern and Western Divisions, Project Use Power Rate...) for Project Use Power for the Pick-Sloan Missouri Basin Program (P-SMBP), Eastern and Western... DEPARTMENT OF THE INTERIOR Bureau of Reclamation Pick-Sloan Missouri Basin Program, Eastern and...

The Sloan Lens ACS Survey. XIII. Discovery of 40 New Galaxy-scale Strong Lenses

Science.gov (United States)

Shu, Yiping; Brownstein, Joel R.; Bolton, Adam S.; Koopmans, Léon V. E.; Treu, Tommaso; Montero-Dorta, Antonio D.; Auger, Matthew W.; Czoske, Oliver; Gavazzi, Raphaël; Marshall, Philip J.; Moustakas, Leonidas A.

2017-12-01

We present the full sample of 118 galaxy-scale strong-lens candidates in the Sloan Lens ACS (SLACS) Survey for the Masses (S4TM) Survey, which are spectroscopically selected from the final data release of the Sloan Digital Sky Survey. Follow-up Hubble Space Telescope (HST) imaging observations confirm that 40 candidates are definite strong lenses with multiple lensed images. The foreground-lens galaxies are found to be early-type galaxies (ETGs) at redshifts 0.06–0.44, and background sources are emission-line galaxies at redshifts 0.22–1.29. As an extension of the SLACS Survey, the S4TM Survey is the first attempt to preferentially search for strong-lens systems with relatively lower lens masses than those in the pre-existing strong-lens samples. By fitting HST data with a singular isothermal ellipsoid model, we find that the total projected mass within the Einstein radius of the S4TM strong-lens sample ranges from 3 × 1010 M ⊙ to 2 × 1011 M ⊙. In Shu et al., we have derived the total stellar mass of the S4TM lenses to be 5 × 1010 M ⊙ to 1 × 1012 M ⊙. Both the total enclosed mass and stellar mass of the S4TM lenses are on average almost a factor of 2 smaller than those of the SLACS lenses, which also represent the typical mass scales of the current strong-lens samples. The extended mass coverage provided by the S4TM sample can enable a direct test, with the aid of strong lensing, for transitions in scaling relations, kinematic properties, mass structure, and dark-matter content trends of ETGs at intermediate-mass scales as noted in previous studies. Based on observations made with the NASA/ESA Hubble Space Telescope (HST), obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555. These observations are associated with HST program #12210.

Candidate isolated neutron stars and other optically blank x-ray fields identified from the rosat all-sky and sloan digital sky surveys

Energy Technology Data Exchange (ETDEWEB)

Agueros, Marcel A.; Anderson, Scott F.; /Washington U., Seattle, Astron. Dept.; Margon, Bruce; /Baltimore, Space Telescope Sci.; Haberl, Frank; Voges, Wolfgang; /Garching,; Annis, James; /Fermilab; Schneider, Donald P.; /Penn State U., Astron. Astrophys.; Brinkmann, Jonathan; /Apache Point Observ.

2005-11-01

Only seven radio-quiet isolated neutron stars (INSs) emitting thermal X rays are known, a sample that has yet to definitively address such fundamental issues as the equation of state of degenerate neutron matter. We describe a selection algorithm based on a cross-correlation of the ROSAT All-Sky Survey (RASS) and the Sloan Digital Sky Survey (SDSS) that identifies X-ray error circles devoid of plausible optical counterparts to the SDSS g {approx} 22 magnitudes limit. We quantitatively characterize these error circles as optically blank; they may host INSs or other similarly exotic X-ray sources such as radio-quiet BL Lacs, obscured AGN, etc. Our search is an order of magnitude more selective than previous searches for optically blank RASS error circles, and excludes the 99.9% of error circles that contain more common X-ray-emitting subclasses. We find 11 candidates, nine of which are new. While our search is designed to find the best INS candidates and not to produce a complete list of INSs in the RASS, it is reassuring that our number of candidates is consistent with predictions from INS population models. Further X-ray observations will obtain pinpoint positions and determine whether these sources are entirely optically blank at g {approx} 22, supporting the presence of likely isolated neutron stars and perhaps enabling detailed follow-up studies of neutron star physics.

RE-EXAMINING HIGH ABUNDANCE SLOAN DIGITAL SKY SURVEY MASS-METALLICITY OUTLIERS: HIGH N/O, EVOLVED WOLF-RAYET GALAXIES?

International Nuclear Information System (INIS)

Berg, Danielle A.; Skillman, Evan D.; Marble, Andrew R.

2011-01-01

We present new MMT spectroscopic observations of four dwarf galaxies representative of a larger sample observed by the Sloan Digital Sky Survey and identified by Peeples et al. as low-mass, high oxygen abundance outliers from the mass-metallicity relation. Peeples showed that these four objects (with metallicity estimates of 8.5 ≤ 12 + log(O/H) ≤ 8.8) have oxygen abundance offsets of 0.4-0.6 dex from the M B luminosity-metallicity relation. Our new observations extend the wavelength coverage to include the [O II] λλ3726, 3729 doublet, which adds leverage in oxygen abundance estimates and allows measurements of N/O ratios. All four spectra are low excitation, with relatively high N/O ratios (N/O ∼> 0.10), each of which tend to bias estimates based on strong emission lines toward high oxygen abundances. These spectra all fall in a regime where the 'standard' strong-line methods for metallicity determinations are not well calibrated either empirically or by photoionization modeling. By comparing our spectra directly to photoionization models, we estimate oxygen abundances in the range of 7.9 ≤ 12 + log (O/H) ≤ 8.4, consistent with the scatter of the mass-metallicity relation. We discuss the physical nature of these galaxies that leads to their unusual spectra (and previous classification as outliers), finding their low excitation, elevated N/O, and strong Balmer absorption are consistent with the properties expected from galaxies evolving past the 'Wolf-Rayet galaxy' phase. We compare our results to the 'main' sample of Peeples and conclude that they are outliers primarily due to enrichment of nitrogen relative to oxygen and not due to unusually high oxygen abundances for their masses or luminosities.

Agreement analysis comparing iPad LCVA and Sloan testing in multiple sclerosis patients.

Science.gov (United States)

Sattarnezhad, Neda; Farrow, Samantha; Kimbrough, Dorlan; Glanz, Bonnie; Healy, Brian; Chitnis, Tanuja

2017-06-01

Visual symptoms are common in multiple sclerosis (MS). Low-contrast visual acuity (LCVA) testing using Sloan charts has demonstrated increased sensitivity for visual deficits compared to high-contrast acuity testing. Computerized testing of visual acuity may facilitate use in the clinic setting. To evaluate the agreement between an iPad-based and Sloan testing of LCVA in a cohort of MS patients. A total of 38 patients with relapsing-remitting MS were enrolled after providing informed written consent at Partners MS Center, Brigham and Women's hospital. Monocular LCVA was measured using retroilluminated Sloan chart and iPad-based LogMAR chart. Number of correct letters and agreement between two measurements were assessed for each eye using Bland-Altman analysis and paired t-test. For both eyes, there was no significant difference in number correct between the two measurements using a paired t-test, and there was high correlation between two measurements (oculus dextrus (OD) r = 0.89, p iPad-based LCVA test shows good agreement with Sloan testing in MS patients.

Customized broadband Sloan-filters for the JST/T250 and JAST/T80 telescopes: measurement summary

Science.gov (United States)

Brauneck, Ulf; Sprengard, Ruediger; Bourquin, Sebastien; Marín-Franch, Antonio

2018-01-01

The Centro de Estudios de Fisica del Cosmos de Aragon will conduct a photometric sky survey with two new telescopes recently set up on the Javalambre mountain in Spain: the JST/T250 is a 2.55-m telescope with a plate scale of 22.67 arc⁢sec/mm and a 3-deg-diameter field of view (FoV) and the auxiliary telescope JAST/T80 with a 82-cm primary mirror and an FoV of 2 deg diameter. A multiple CCD (9k-by-9k array size, 10-μm pixel size) mosaic camera is used in combination with filter trays or filter wheels, each containing a multitude of filters in dimensions of 101.7×96.5 mm or 106.8×106.8 mm. For this project, Schott manufactured 56 specially designed narrow band steep-edged bandpass interference filters and five broadband Sloan-filters which were completed only recently. We report here on the results of the broadband Sloan-filters with transmission bands of 324 to 400 nm (Sloan-u), 400 to 550 nm (Sloan-g), 550 to 700 nm (Sloan-r), 695 to 850 nm (Sloan-i), and 830 to 1200 nm (Sloan-z). The filters are composed of Schott filterglasses and clearglass substrates coated with interference filters and represent an improvement of broadband Sloan filters commonly used in astronomy. In spite of the absorptive elements, the filters show maximum possible transmissions achieved by magnetron sputtered filter coatings. In addition, the blocking of the filters is better than OD5 (transmission <10 to -5) in the range 250 to 1050 nm which was achieved by combining up to three substrates. A high image quality required a low transmitted wavefront error (<λ/8 locally, respectively <λ/2 globally). We report on the spectral and interferometric results measured on the filters.

Local starburst galaxies and their descendants. Statistics from the Sloan Digital Sky Survey

Science.gov (United States)

Bergvall, Nils; Marquart, Thomas; Way, Michael J.; Blomqvist, Anna; Holst, Emma; Ostlin, Goran; Zackrisson, Erik

2016-01-01

Despite strong interest in the starburst phenomenon in extragalactic astronomy, the concept remains ill-defined. Here we use a strict definition of starburst to examine the statistical properties of starburst galaxies in the local universe. We also seek to establish links between starburst galaxies, post-starburst (hereafter postburst) galaxies, and active galaxies. Data were selected from the Sloan Digital Sky Survey DR7. We applied a novel method of treating dust attenuation and derive star formation rates, ages, and stellar masses assuming a two-component stellar population model. Dynamical masses are calculated from the width of the H-alpha line. These masses agree excellently with the photometric masses. The mass (gas+stars) range is approximately 10( exp 9) - 10(exp 11.5) solar mass. As a selection criterion for starburst galaxies, we use, the birthrate parameter, b = SFR/SFR, requiring that b is greater than 3. For postburst galaxies, we use, the equivalent width of Hdelta in absorption with the criterion EW (sub Hdelta_abs) is greater than 6 A. Results. We find that only 1% of star-forming galaxies are starburst galaxies. They contribute 3-6% to the stellar production and are therefore unimportant for the local star formation activity. The median starburst age is 70 Myr roughly independent of mass, indicating that star formation is mainly regulated by local feedback processes. The b-parameter strongly depends on burst age. Values close to b = 60 are found at ages approximately 10 Myr, while almost no starbursts are found at ages greater than 1 Gyr. The median baryonic burst mass fraction of sub-L galaxies is 5% and decreases slowly towards high masses. The median mass fraction of the recent burst in the postburst sample is 5-10%. A smaller fraction of the postburst galaxies, however, originates in non-bursting galaxies. The age-mass distribution of the postburst progenitors (with mass fractions is greater than 3%) is bimodal with a break at logM(solar mass

Lung cancer detection with digital chest tomosynthesis: first round results from the SOS observational study.

Science.gov (United States)

Bertolaccini, Luca; Viti, Andrea; Tavella, Chiara; Priotto, Roberto; Ghirardo, Donatella; Grosso, Maurizio; Terzi, Alberto

2015-04-01

Baseline results of the Studio OSservazionale (SOS), observational study, a single-arm observational study of digital chest tomosynthesis for lung cancer detection in an at-risk population demonstrated a detection rate of lung cancer comparable to that of studies that used low dose CT scan (LDCT). We present the results of the first round. Totally 1,703 out of 1,843 (92%) subjects who had a baseline digital chest tomosynthesis underwent a first round reevaluation after 1 year. At first round chest digital tomosynthesis, 13 (0.7%) subjects had an indeterminate nodule larger than 5 mm and underwent low-dose CT scan for nodule confirmation. PET/CT study was obtained in 10 (0.5%) subjects and 2 subjects had a low-dose CT follow up. Surgery, either video-assisted thoracoscopic or open surgery for indeterminate pulmonary nodules was performed in 10 (0.2%) subjects. A lung cancer was diagnosed and resected in five patients. The lung cancer detection rate at first round was 0.3% (5/1,703). The detection rate of lung cancer at first round for tomosynthesis is comparable to rates reported for CT. In addition, results of first round digital chest tomosynthesis confirm chest tomosynthesis as a possible first-line lung cancer-screening tool.

The C4 clustering algorithm: Clusters of galaxies in the Sloan Digital Sky Survey

Energy Technology Data Exchange (ETDEWEB)

Miller, Christopher J.; Nichol, Robert; Reichart, Dan; Wechsler, Risa H.; Evrard, August; Annis, James; McKay, Timothy; Bahcall, Neta; Bernardi, Mariangela; Boehringer,; Connolly, Andrew; Goto, Tomo; Kniazev, Alexie; Lamb, Donald; Postman, Marc; Schneider, Donald; Sheth, Ravi; Voges, Wolfgang; /Cerro-Tololo InterAmerican Obs. /Portsmouth U.,

2005-03-01

We present the ''C4 Cluster Catalog'', a new sample of 748 clusters of galaxies identified in the spectroscopic sample of the Second Data Release (DR2) of the Sloan Digital Sky Survey (SDSS). The C4 cluster-finding algorithm identifies clusters as overdensities in a seven-dimensional position and color space, thus minimizing projection effects that have plagued previous optical cluster selection. The present C4 catalog covers {approx}2600 square degrees of sky and ranges in redshift from z = 0.02 to z = 0.17. The mean cluster membership is 36 galaxies (with redshifts) brighter than r = 17.7, but the catalog includes a range of systems, from groups containing 10 members to massive clusters with over 200 cluster members with redshifts. The catalog provides a large number of measured cluster properties including sky location, mean redshift, galaxy membership, summed r-band optical luminosity (L{sub r}), velocity dispersion, as well as quantitative measures of substructure and the surrounding large-scale environment. We use new, multi-color mock SDSS galaxy catalogs, empirically constructed from the {Lambda}CDM Hubble Volume (HV) Sky Survey output, to investigate the sensitivity of the C4 catalog to the various algorithm parameters (detection threshold, choice of passbands and search aperture), as well as to quantify the purity and completeness of the C4 cluster catalog. These mock catalogs indicate that the C4 catalog is {approx_equal}90% complete and 95% pure above M{sub 200} = 1 x 10{sup 14} h{sup -1}M{sub {circle_dot}} and within 0.03 {le} z {le} 0.12. Using the SDSS DR2 data, we show that the C4 algorithm finds 98% of X-ray identified clusters and 90% of Abell clusters within 0.03 {le} z {le} 0.12. Using the mock galaxy catalogs and the full HV dark matter simulations, we show that the L{sub r} of a cluster is a more robust estimator of the halo mass (M{sub 200}) than the galaxy line-of-sight velocity dispersion or the richness of the cluster

Clustering of High Redshift (z>2.9) Quasars from the Sloan Digital Sky Survey

Energy Technology Data Exchange (ETDEWEB)

Shen, Yue; Strauss, Michael A.; Oguri, Masamune; Hennawi, Joseph F.; Fan, Xiaohui; Richards, Gordon T.; Hall, Patrick B.; Schneider, Donald P.; Szalay, Alexander S.; Thakar, Anirudda R.; Berk, Daniel E.Vanden; Anderson, Scott F.; Bahcall, Neta A.; /KIPAC, Menlo Park

2006-11-30

We study the two-point correlation function of a uniformly selected sample of 4,428 optically selected luminous quasars with redshift 2.9 {le} z {le} 5.4 selected over 4041 deg{sup 2} from the Fifth Data Release of the Sloan Digital Sky Survey. We fit a power-law to the projected correlation function w{sub p}(r{sub p}) to marginalize over redshift space distortions and redshift errors. For a real-space correlation function of the form {zeta}(r) = (r/r{sub 0}){sup -{gamma}}, the fitted parameters in comoving coordinates are r{sub 0} = 15.2 {+-} 2.7 h{sup -1} Mpc and {gamma} = 2.0 {+-} 0.3, over a scale range 4 {le} r{sub p} {le} 150 h{sup -1} Mpc. Thus high-redshift quasars are appreciably more strongly clustered than their z {approx} 1.5 counterparts, which have a comoving clustering length r{sub 0} {approx} 6.5 h{sup -1} Mpc. Dividing our sample into two redshift bins: 2.9 {le} z {le} 3.5 and z {ge} 3.5, and assuming a power-law index {gamma} = 2.0, we find a correlation length of r{sub 0} = 16.9 {+-} 1.7 h{sup -1} Mpc for the former, and r{sub 0} = 24.3 {+-} 2.4 h{sup -1} Mpc for the latter. Strong clustering at high redshift indicates that quasars are found in very massive, and therefore highly biased, halos. Following Martini & Weinberg, we relate the clustering strength and quasar number density to the quasar lifetimes and duty cycle. Using the Sheth & Tormen halo mass function, the quasar lifetime is estimated to lie in the range 4 {approx} 50 Myr for quasars with 2.9 {le} z {le} 3.5; and 30 {approx} 600 Myr for quasars with z {ge} 3.5. The corresponding duty cycles are 0.004 {approx} 0.05 for the lower redshift bin and 0.03 {approx} 0.6 for the higher redshift bin. The minimum mass of halos in which these quasars reside is 2-3 x 10{sup 12} h{sup -1} M{sub {circle_dot}} for quasars with 2.9 {le} z {le} 3.5 and 4-6 x 10{sup 12} h{sup -1} M{sub {circle_dot}} for quasars with z {ge} 3.5; the effective bias factor b{sub eff} increases with redshift, e.g., b

LUMINOSITY FUNCTIONS OF TYPE Ia SUPERNOVAE AND THEIR HOST GALAXIES FROM THE SLOAN DIGITAL SKY SURVEY

International Nuclear Information System (INIS)

Yasuda, Naoki; Fukugita, Masataka

2010-01-01

The sample of 137 low-redshift type Ia supernovae (SNe Ia) with 0.05 ≤ z ≤ 0.3 obtained from the Sloan Digital Sky Survey (SDSS)-II supernova survey for the southern equatorial stripe of 300 deg 2 is used to derive the luminosity functions (LFs) of SNe Ia and of their host galaxies in the g, r, i passbands. We show that the LF of SNe Ia host galaxies matches well with that of galaxies in the general field, suggesting that the occurrence of SNe Ia does not favor a particular type of galaxy but is predominantly proportional to the luminosity of galaxies. The evidence is weak that the SNe rate varies with the color of host galaxies. The only evidence that points to possible correlation between the SN rate and star formation activity is that the SN rate in late-type galaxies is higher than that in early-type galaxies by 31% ± 35%. In our low-redshift sample, the component of type Ia SN rate that is proportional to star formation activity is not evident in the integrated SN rate, while our observation is compatible with the current two-component models. The sample contains eight SNe Ia whose host galaxies were not identified, but it is shown that their occurrence is consistent with them occurring in low-luminous galaxies beyond the survey. The LF of SNe Ia is approximately Gaussian with the full width at half-maximum being a factor of σ = 0.24 mag or 1.67 in luminosity. The Gaussian distribution becomes tighter if the ratio of extinction to reddening, R V , is lower than the characteristic value for the Milky Way and if luminosity is corrected for the light-curve shape. The average color excess is ∼0.07 mag, which is significantly smaller than reddening expected for field galaxies. This color excess does not vary with the distance of the SNe from the center of the host galaxy to 15 kpc. This suggests that the major part of the color excess appears to be either intrinsic or reddening that arises in the immediate environment of SNe, rather than interstellar

Digital subtraction angiography: first 900 cases

International Nuclear Information System (INIS)

Rodgers, H.

1984-01-01

The diagnostic technique of digital subtraction angiography (DSA) is briefly outlined. The operational and technical experiences with a DR-960 DSA system used in the examination of the first 900 cases at St. Thomas' Hospital, London are described. (U.K.)

Medicinal use of earths and minerals from Hippocrates to Sir Hans Sloane and beyond.

Science.gov (United States)

Retsas, Spyros

2012-12-01

In 1931 two pharmaceutical drawers containing mineral specimens, belonging to Sir Hans Sloane, the 18th century collector, Royal Physician, President of the Royal Society and of the Royal College of Physicians of London, were found in the Department of Botany of the Natural History Museum (NHM) of London. The drawers, each divided into 49 compartments, contained a total of 107 mineral pharmaceutical specimens, some labelled as mercury or white arsenic. Their registration, identification with the Sloane Manuscript Catalogues and subsequent transfer to the Mineralogy department of the NHM where one of these drawers is now on public display, had been documented by 1935. In antiquity therapeutic empiricism attributed medicinal properties to animal products, plants and minerals, including the soil of specific geographic locations. This communication traces the medicinal use of certain earths and minerals, listed in Sir Hans Sloane's manuscript catalogues, to classical antiquity with a reference to Arsenic compounds, which in our time are finding application in the treatment of acute promyelocytic leukaemia and to Terra Lemnia, a celebrated antidote of repute spanning twenty centuries, also included in the Sloane collections.

The Development of Arabic Digit Knowledge in 4- to 7-Year-Old Children

Directory of Open Access Journals (Sweden)

Birgit Knudsen

2015-10-01

Full Text Available Recent studies indicate that Arabic digit knowledge rather than non-symbolic number knowledge is a key foundation for arithmetic proficiency at the start of a child’s mathematical career. We document the developmental trajectory of 4- to 7-year-olds’ proficiency in accessing magnitude information from Arabic digits in five tasks differing in magnitude manipulation requirements. Results showed that children from 5 years onwards accessed magnitude information implicitly and explicitly, but that 5-year-olds failed to access magnitude information explicitly when numerical magnitude was contrasted with physical magnitude. Performance across tasks revealed a clear developmental trajectory: children traverse from first knowing the cardinal values of number words to recognizing Arabic digits to knowing their cardinal values and, concurrently, their ordinal position. Correlational analyses showed a strong within-child consistency, demonstrating that this pattern is not only reflected in group differences but also in individual performance.

THE SLOAN DIGITAL SKY SURVEY REVERBERATION MAPPING PROJECT: BIASES IN z  > 1.46 REDSHIFTS DUE TO QUASAR DIVERSITY

Energy Technology Data Exchange (ETDEWEB)

Denney, K. D.; Peterson, B. M. [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Horne, Keith [SUPA Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS (United Kingdom); Brandt, W. N.; Grier, C. J.; Trump, J. R. [Department of Astronomy and Astrophysics, 525 Davey Lab, The Pennsylvania State University, University Park, PA 16802 (United States); Ho, Luis C. [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China); Ge, J., E-mail: denney@astronomy.ohio-state.edu [Astronomy Department University of Florida 211 Bryant Space Science Center P.O. Box 112055 Gainesville, FL 32611-2055 (United States)

2016-12-10

We use the coadded spectra of 32 epochs of Sloan Digital Sky Survey (SDSS) Reverberation Mapping Project observations of 482 quasars with z  > 1.46 to highlight systematic biases in the SDSS- and Baryon Oscillation Spectroscopic Survey (BOSS)-pipeline redshifts due to the natural diversity of quasar properties. We investigate the characteristics of this bias by comparing the BOSS-pipeline redshifts to an estimate from the centroid of He ii λ 1640. He ii has a low equivalent width but is often well-defined in high-S/N spectra, does not suffer from self-absorption, and has a narrow component which, when present (the case for about half of our sources), produces a redshift estimate that, on average, is consistent with that determined from [O ii] to within the He ii and [O ii] centroid measurement uncertainties. The large redshift differences of ∼1000 km s{sup −1}, on average, between the BOSS-pipeline and He ii-centroid redshifts, suggest there are significant biases in a portion of BOSS quasar redshift measurements. Adopting the He ii-based redshifts shows that C iv does not exhibit a ubiquitous blueshift for all quasars, given the precision probed by our measurements. Instead, we find a distribution of C iv-centroid blueshifts across our sample, with a dynamic range that (i) is wider than that previously reported for this line, and (ii) spans C iv centroids from those consistent with the systemic redshift to those with significant blueshifts of thousands of kilometers per second. These results have significant implications for measurement and use of high-redshift quasar properties and redshifts, and studies based thereon.

The Sloan Digital Sky Survey Stripe 82 Imaging Data: Depth-Optimized Co-adds Over 300 deg$^2$ in Five Filters

Energy Technology Data Exchange (ETDEWEB)

Jiang, Linhua; Fan, Xiaohui; Bian, Fuyan; McGreer, Ian D.; Strauss, Michael A.; Annis, James; Buck, Zoë; Green, Richard; Hodge, Jacqueline A.; Myers, Adam D.; Rafiee, Alireza; Richards, Gordon

2014-06-25

We present and release co-added images of the Sloan Digital Sky Survey (SDSS) Stripe 82. Stripe 82 covers an area of ~300 deg(2) on the celestial equator, and has been repeatedly scanned 70-90 times in the ugriz bands by the SDSS imaging survey. By making use of all available data in the SDSS archive, our co-added images are optimized for depth. Input single-epoch frames were properly processed and weighted based on seeing, sky transparency, and background noise before co-addition. The resultant products are co-added science images and their associated weight images that record relative weights at individual pixels. The depths of the co-adds, measured as the 5σ detection limits of the aperture (3.''2 diameter) magnitudes for point sources, are roughly 23.9, 25.1, 24.6, 24.1, and 22.8 AB magnitudes in the five bands, respectively. They are 1.9-2.2 mag deeper than the best SDSS single-epoch data. The co-added images have good image quality, with an average point-spread function FWHM of ~1'' in the r, i, and z bands. We also release object catalogs that were made with SExtractor. These co-added products have many potential uses for studies of galaxies, quasars, and Galactic structure. We further present and release near-IR J-band images that cover ~90 deg(2) of Stripe 82. These images were obtained using the NEWFIRM camera on the NOAO 4 m Mayall telescope, and have a depth of about 20.0-20.5 Vega magnitudes (also 5σ detection limits for point sources).

THE SLOAN DIGITAL SKY SURVEY REVERBERATION MAPPING PROJECT: BIASES IN z  > 1.46 REDSHIFTS DUE TO QUASAR DIVERSITY

International Nuclear Information System (INIS)

Denney, K. D.; Peterson, B. M.; Horne, Keith; Brandt, W. N.; Grier, C. J.; Trump, J. R.; Ho, Luis C.; Ge, J.

2016-01-01

We use the coadded spectra of 32 epochs of Sloan Digital Sky Survey (SDSS) Reverberation Mapping Project observations of 482 quasars with z  > 1.46 to highlight systematic biases in the SDSS- and Baryon Oscillation Spectroscopic Survey (BOSS)-pipeline redshifts due to the natural diversity of quasar properties. We investigate the characteristics of this bias by comparing the BOSS-pipeline redshifts to an estimate from the centroid of He ii λ 1640. He ii has a low equivalent width but is often well-defined in high-S/N spectra, does not suffer from self-absorption, and has a narrow component which, when present (the case for about half of our sources), produces a redshift estimate that, on average, is consistent with that determined from [O ii] to within the He ii and [O ii] centroid measurement uncertainties. The large redshift differences of ∼1000 km s −1 , on average, between the BOSS-pipeline and He ii-centroid redshifts, suggest there are significant biases in a portion of BOSS quasar redshift measurements. Adopting the He ii-based redshifts shows that C iv does not exhibit a ubiquitous blueshift for all quasars, given the precision probed by our measurements. Instead, we find a distribution of C iv-centroid blueshifts across our sample, with a dynamic range that (i) is wider than that previously reported for this line, and (ii) spans C iv centroids from those consistent with the systemic redshift to those with significant blueshifts of thousands of kilometers per second. These results have significant implications for measurement and use of high-redshift quasar properties and redshifts, and studies based thereon.

Tennessee Valley Authority becomes first to install digital process protection system

International Nuclear Information System (INIS)

Miller, W.; Doyle, J.

1991-01-01

Westinghouse Pressurized Water Reactors were originally furnished with analog process protection equipment of various vintages. The older equipment is quickly reaching the point of obsolescence, becoming costly to maintain and operate, its qualification increasingly difficult to achieve. Newer digital-based systems offer improved performance, automatic calibration, and streamlined surveillance test features, as discussed here. For these reasons, the Tennessee Valley Authority installed the world's first digital process protection system, complete with automatic test and calibration features, in its Sequoyah units 1 and 2 last year. The US utility replaced its ageing analog system with Westinghouse Electric's Eagle 21 Process Protection System during a routine maintenance shutdown in a record 23 days. (author)

Customized broadband sloan-filters for the JST/T250 and JAST/T80 telescopes: summary of results

Science.gov (United States)

Brauneck, U.; Sprengard, R.; Bourquin, S.; Marín-Franch, A.

2017-09-01

The Centro de Estudios de Fisica del Cosmos de Aragon (CEFCA) will conduct a photometric sky survey with 2 new telescopes recently setup on the Javalambre mountain in Spain: the JST/T250 is a 2.55m telescope with a plate scale of 22.67"/mm and a 3° diameter field of view (FoV) and the auxiliary telescope JAST/T80 with a 82cm primary mirror and a FoV of 2 deg diameter. A multiple CCD (9k-by-9k array size, 10μm pixel size) mosaic camera is used in combination with filter trays or filter wheels, each containing a multitude of filters in dimensions of 101.7x96.5mm or 106.8x106.8mm. For this project, SCHOTT manufactured 56 specially designed narrow band steep edged bandpass interference filters and 5 broadband sloan-filters which were completed only recently. We report here on the results of the broadband sloanfilters with transmission bands of 324-400nm (sloan-u), 400-550nm (sloan-g), 550-700nm (sloan-r), 695-850nm (sloan-i) and 830-1200nm (sloan-z). The filters are composed of SCHOTT filterglasses and clearglass substrates coated with interference filters and represent an improvement of broadband sloan filters commonly used in astronomy. Inspite of the absorptive elements, the filters show maximum possible transmissions achieved by magnetron sputtered filter coatings. In addition the blocking of the filters is better than OD5 in the range 250-1050nm. A high image quality required a low transmitted wavefront error (<λ/8 locally, respectively <λ/2 globally) which was achieved by combining up to 2 substrates. We report on the spectral and interferometric results measured on the filters.

The Memorial Sloan Kettering Cancer Center Recommendations for Prostate Cancer Screening.

Science.gov (United States)

Vickers, Andrew J; Eastham, James A; Scardino, Peter T; Lilja, Hans

2016-05-01

The Memorial Sloan Kettering Cancer Center (MSKCC) recommendations on prostate cancer screening were developed in response to three limitations of previous screening guidelines: insufficient evidence base, failure to link screening with treatment, and lack of risk stratification. The objective of the recommendations is to provide a schema for prostate cancer screening that maximizes the benefits, in terms of reduction in prostate cancer-specific mortality, and minimizes the harms, in terms of overdiagnosis and overtreatment. We recommend the following schema for men choosing to be screened following informed decision-making: starting at age 45, prostate-specific antigen (PSA) without digital rectal examination. If PSA ≥ 3 ng/mL: consider prostate biopsy; if PSA ≥ 1 but decision to biopsy a man with a PSA > 3 ng/mL should be based on a variety of factors including repeat blood draw for confirmatory testing of the PSA level, digital rectal examination results, and workup for benign disease. Additional reflex tests in blood such as a free-to-total PSA ratio, the Prostate Health Index, or 4Kscore, or urinary testing of PCA3, can also be informative in some patients. The best evidence suggests that more restricted indication for prostate biopsy and a more focused approach to pursue screening in men at highest risk of lethal cancer would retain most of the mortality benefits of aggressive screening schema, while importantly reducing harms from overdetection and overtreatment. Copyright © 2016 Elsevier Inc. All rights reserved.

Student Communication and Study Habits of First-Year University Students in the Digital Era

Science.gov (United States)

Gallardo-Echenique, Eliana; Bullen, Mark; Marqués-Molías, Luis

2016-01-01

This paper reports on research into the study habits of-university students, their use digital technologies and how they communicate with each other and their professors. We conclude that most students feel comfortable with digital technologies and that they use social media for connecting and interacting with friends rather than for academic…

Sloan Digital Sky Survey III photometric quasar clustering: probing the initial conditions of the Universe

Energy Technology Data Exchange (ETDEWEB)

Ho, Shirley; Agarwal, Nishant; Lyons, Richard; Disbrow, Ashley; O' Connell, Ross [McWilliams Center for Cosmology, Department of Physics, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213 (United States); Myers, Adam D. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Seo, Hee-Jong; Schlegel, David; Ross, Nicholas P. [Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA 94702 (United States); Ross, Ashley [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Portsmouth, PO1 3FX (United Kingdom); Hirata, Christopher; Huff, Eric; Weinberg, David [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Padmanabhan, Nikhil [Department of Physics and Astronomy, Yale University, New Haven, CT 06520 (United States); Slosar, Anže [Brookhaven National Laboratory, Bldg. 510, Upton NY 11375 (United States); Strauss, Michael; Bahcall, Neta [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Schneider, Donald P. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Brinkmann, J. [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349-0059 (United States); Palanque-Delabrouille, Nathalie, E-mail: shirleyh@andrew.cmu.edu [CEA, Centre de Saclay, Irfu/SPP, F-91191 Gif-sur-Yvette (France); and others

2015-05-01

The Sloan Digital Sky Survey has surveyed 14,555 square degrees of the sky, and delivered over a trillion pixels of imaging data. We present the large-scale clustering of 1.6 million quasars between z=0.5 and z=2.5 that have been classified from this imaging, representing the highest density of quasars ever studied for clustering measurements. This data set spans 0∼ 11,00 square degrees and probes a volume of 80 h{sup −3} Gpc{sup 3}. In principle, such a large volume and medium density of tracers should facilitate high-precision cosmological constraints. We measure the angular clustering of photometrically classified quasars using an optimal quadratic estimator in four redshift slices with an accuracy of ∼ 25% over a bin width of δ{sub l} ∼ 10−15 on scales corresponding to matter-radiation equality and larger (0ℓ ∼ 2−3). Observational systematics can strongly bias clustering measurements on large scales, which can mimic cosmologically relevant signals such as deviations from Gaussianity in the spectrum of primordial perturbations. We account for systematics by employing a new method recently proposed by Agarwal et al. (2014) to the clustering of photometrically classified quasars. We carefully apply our methodology to mitigate known observational systematics and further remove angular bins that are contaminated by unknown systematics. Combining quasar data with the photometric luminous red galaxy (LRG) sample of Ross et al. (2011) and Ho et al. (2012), and marginalizing over all bias and shot noise-like parameters, we obtain a constraint on local primordial non-Gaussianity of f{sub NL} = −113{sup +154}{sub −154} (1σ error). We next assume that the bias of quasar and galaxy distributions can be obtained independently from quasar/galaxy-CMB lensing cross-correlation measurements (such as those in Sherwin et al. (2013)). This can be facilitated by spectroscopic observations of the sources, enabling the redshift distribution to be

A large sample of Kohonen selected E+A (post-starburst) galaxies from the Sloan Digital Sky Survey

Science.gov (United States)

Meusinger, H.; Brünecke, J.; Schalldach, P.; in der Au, A.

2017-01-01

Context. The galaxy population in the contemporary Universe is characterised by a clear bimodality, blue galaxies with significant ongoing star formation and red galaxies with only a little. The migration between the blue and the red cloud of galaxies is an issue of active research. Post starburst (PSB) galaxies are thought to be observed in the short-lived transition phase. Aims: We aim to create a large sample of local PSB galaxies from the Sloan Digital Sky Survey (SDSS) to study their characteristic properties, particularly morphological features indicative of gravitational distortions and indications for active galactic nuclei (AGNs). Another aim is to present a tool set for an efficient search in a large database of SDSS spectra based on Kohonen self-organising maps (SOMs). Methods: We computed a huge Kohonen SOM for ∼106 spectra from SDSS data release 7. The SOM is made fully available, in combination with an interactive user interface, for the astronomical community. We selected a large sample of PSB galaxies taking advantage of the clustering behaviour of the SOM. The morphologies of both PSB galaxies and randomly selected galaxies from a comparison sample in SDSS Stripe 82 (S82) were inspected on deep co-added SDSS images to search for indications of gravitational distortions. We used the Portsmouth galaxy property computations to study the evolutionary stage of the PSB galaxies and archival multi-wavelength data to search for hidden AGNs. Results: We compiled a catalogue of 2665 PSB galaxies with redshifts z 3 Å and z cloud, in agreement with the idea that PSB galaxies represent the transitioning phase between actively and passively evolving galaxies. The relative frequency of distorted PSB galaxies is at least 57% for EW(Hδ) > 5 Å, significantly higher than in the comparison sample. The search for AGNs based on conventional selection criteria in the radio and MIR results in a low AGN fraction of ∼2-3%. We confirm an MIR excess in the mean SED of

Galaxy Evolution Insights from Spectral Modeling of Large Data Sets from the Sloan Digital Sky Survey

Energy Technology Data Exchange (ETDEWEB)

Hoversten, Erik A. [Johns Hopkins Univ., Baltimore, MD (United States)

2007-10-01

This thesis centers on the use of spectral modeling techniques on data from the Sloan Digital Sky Survey (SDSS) to gain new insights into current questions in galaxy evolution. The SDSS provides a large, uniform, high quality data set which can be exploited in a number of ways. One avenue pursued here is to use the large sample size to measure precisely the mean properties of galaxies of increasingly narrow parameter ranges. The other route taken is to look for rare objects which open up for exploration new areas in galaxy parameter space. The crux of this thesis is revisiting the classical Kennicutt method for inferring the stellar initial mass function (IMF) from the integrated light properties of galaxies. A large data set (~ 10⁵ galaxies) from the SDSS DR4 is combined with more in-depth modeling and quantitative statistical analysis to search for systematic IMF variations as a function of galaxy luminosity. Galaxy Hα equivalent widths are compared to a broadband color index to constrain the IMF. It is found that for the sample as a whole the best fitting IMF power law slope above 0.5 M_⊙ is Γ = 1.5 ± 0.1 with the error dominated by systematics. Galaxies brighter than around M_r,0.1 = -20 (including galaxies like the Milky Way which has M_r,0.1 ~ -21) are well fit by a universal Γ ~ 1.4 IMF, similar to the classical Salpeter slope, and smooth, exponential star formation histories (SFH). Fainter galaxies prefer steeper IMFs and the quality of the fits reveal that for these galaxies a universal IMF with smooth SFHs is actually a poor assumption. Related projects are also pursued. A targeted photometric search is conducted for strongly lensed Lyman break galaxies (LBG) similar to MS1512-cB58. The evolution of the photometric selection technique is described as are the results of spectroscopic follow-up of the best targets. The serendipitous discovery of two interesting blue compact dwarf galaxies is reported. These

CATACLYSMIC VARIABLES FROM SDSS. VII. THE SEVENTH YEAR (2006)

International Nuclear Information System (INIS)

Szkody, Paula; Anderson, Scott F.; Hayden, Michael; Kronberg, Martin; McGurk, Rosalie; Riecken, Thomas; Schmidt, Gary D.; West, Andrew A.; Gaensicke, Boris T.; Gomez-Moran, Ada N.; Schwope, Axel D.; Schneider, Donald P.; Schreiber, Matthias R.

2009-01-01

Coordinates, magnitudes, and spectra are presented for 39 cataclysmic variables (CVs) found in Sloan Digital Sky Survey (SDSS) spectra that were primarily obtained in 2006. Of these, 13 were CVs identified prior to the SDSS spectra (AK Cnc, GY Cnc, GO Com, ST LMi, NY Ser, MR Ser, QW Ser, EU UMa, IY UMa, HS1340+1524, RXJ1610.1+0352, Boo 1, Leo 5). Follow-up spectroscopic observations of seven systems (including one from year 2005 and another from year 2004) were obtained, resulting in estimates of the orbital periods for three objects. The new CVs include two candidates for high inclination, eclipsing systems, four new polars, and three systems whose spectra clearly reveal atmospheric absorption lines from the underlying white dwarf.

Statement on the first research on digital startups in Poland

Directory of Open Access Journals (Sweden)

Agnieszka Skala

2016-10-01

Full Text Available The objective of the paper is to present the results of the first study of Polish startups’ ecosystem as the first stage of a larger study of digital economy landscape in Poland. The first estimate of the number of Polish startups amounts to 2400 entities. The publication presents the first survey Polish startups that marks the beginning of cyclical studies on enterprises belonging to the digital economy in Poland. The study was conducted among 423 entities using an in-house questionnaire prepared based on the author’s own knowledge. Results are discussed. Startups most often consider themselves software producers who follow the SaaS model and operate in the following industries: mobile apps, e-commerce and Internet services. Nearly one in three startups achieve 50% annual revenue growth, while in one-fifth such growth exceeds 100%. Almost two thirds of Polish startups are financed exclusively from own funds. It is necessary to repeat and deepen the study in order to determining the significance of the digital industry in the economy of Poland and the CEE region. The originality of this work lies in taking this subject for the first time in Polish literature and in elaborating the proposition of a “startup” term’s definition.

Benford analysis of quantum critical phenomena: First digit provides high finite-size scaling exponent while first two and further are not much better

Science.gov (United States)

Bera, Anindita; Mishra, Utkarsh; Singha Roy, Sudipto; Biswas, Anindya; Sen(De), Aditi; Sen, Ujjwal

2018-06-01

Benford's law is an empirical edict stating that the lower digits appear more often than higher ones as the first few significant digits in statistics of natural phenomena and mathematical tables. A marked proportion of such analyses is restricted to the first significant digit. We employ violation of Benford's law, up to the first four significant digits, for investigating magnetization and correlation data of paradigmatic quantum many-body systems to detect cooperative phenomena, focusing on the finite-size scaling exponents thereof. We find that for the transverse field quantum XY model, behavior of the very first significant digit of an observable, at an arbitrary point of the parameter space, is enough to capture the quantum phase transition in the model with a relatively high scaling exponent. A higher number of significant digits do not provide an appreciable further advantage, in particular, in terms of an increase in scaling exponents. Since the first significant digit of a physical quantity is relatively simple to obtain in experiments, the results have potential implications for laboratory observations in noisy environments.

Using Digital Storytelling to Help First-Grade Students' Adjustment to School

OpenAIRE

Fokides, Emanuel

2015-01-01

When coming to school for the first time, children might face a number of adjustment problems. The study presents the results of a project which used digital storytelling for helping first-grade primary school students during this transitional period. It was examined whether, through the development of the digital stories, students could understand how the school functions and whether this process helped them to change their attitudes and behaviors, thus achieving a smoother adaptation to the...

Comparison of the unitary pole and Adhikari-Sloan expansions in the three nucleon system

International Nuclear Information System (INIS)

Afnan, I.R.; Birrell, N.D.

1977-01-01

The binding energy of 3 H, percentage S-, S'- and D-state probability, and charge form factor of 3 He are calculated using the unitary pole and Adhikari-Sloan separable expansions to the Reid soft core potential. Comparison of the results for the two separable expansions show that the expansion of Adhikari and Sloan has the better convergence property, and the lowest rank expansion considered (equivalent to the unitary pole approximation) gives a good approximation to the binding energy of 3 H and the charge form factor of 3 He, even at large momentum transfer (K 2 -2 ). (Author)

First-year seminar intervention: Enhancing first- year mathematics ...

African Journals Online (AJOL)

year Seminar and the mathematics performance of first-year students in Science? .... generation students enter the new higher education environment (Briggs, Clark ..... institution-wide approaches to enact the FYE as “everybody's business”.

A first experience with digital complete overdentures

Directory of Open Access Journals (Sweden)

Salwa Omar Bajunaid

2016-07-01

Full Text Available The development of computer-aided design/computer-aided manufacturing systems for dentistry in the 1980s resulted in the successful fabrication of crowns, fixed dental prostheses, and superstructures for both natural teeth and dental implants. Today, this technology is available for constructing digitally designed and milled, completely removable dental prostheses. The procedure uses clinical and laboratory protocols that allow fabrication of completely removable prostheses within two clinical appointments. The aim of this clinical report is to present the author’s first experience with digital complete overdentures, the practicality of this technology, and patient feedback. Compared with conventional overdentures, the fit of the digital prostheses was improved because the cameo and flanges of the prostheses were nicely shaped and rolled, and this enhanced their stability and retention. Occlusion was also excellent. However, aesthetics in terms of the alignment, shape, and size of the maxillary overdenture teeth were inacceptable. Despite some of the drawbacks identified in our study, the use of removable digital dentures does provide excellent adaptation of the denture base and requires fewer clinic visits. We anticipate that the unsatisfactory aesthetic outcomes presented in this report can be corrected with more experience. We also believe that acquiring an in-house scanning machine would be beneficial. We highly recommend including this technique in dental school curriculums at both the undergraduate and graduate levels in order to keep students and residents up to date on the latest technology available.

A first experience with digital complete overdentures.

Science.gov (United States)

Bajunaid, Salwa Omar

2016-07-01

The development of computer-aided design/computer-aided manufacturing systems for dentistry in the 1980s resulted in the successful fabrication of crowns, fixed dental prostheses, and superstructures for both natural teeth and dental implants. Today, this technology is available for constructing digitally designed and milled, completely removable dental prostheses. The procedure uses clinical and laboratory protocols that allow fabrication of completely removable prostheses within two clinical appointments. The aim of this clinical report is to present the author's first experience with digital complete overdentures, the practicality of this technology, and patient feedback. Compared with conventional overdentures, the fit of the digital prostheses was improved because the cameo and flanges of the prostheses were nicely shaped and rolled, and this enhanced their stability and retention. Occlusion was also excellent. However, aesthetics in terms of the alignment, shape, and size of the maxillary overdenture teeth were inacceptable. Despite some of the drawbacks identified in our study, the use of removable digital dentures does provide excellent adaptation of the denture base and requires fewer clinic visits. We anticipate that the unsatisfactory aesthetic outcomes presented in this report can be corrected with more experience. We also believe that acquiring an in-house scanning machine would be beneficial. We highly recommend including this technique in dental school curriculums at both the undergraduate and graduate levels in order to keep students and residents up to date on the latest technology available.

CLUSTERING OF SLOAN DIGITAL SKY SURVEY III PHOTOMETRIC LUMINOUS GALAXIES: THE MEASUREMENT, SYSTEMATICS, AND COSMOLOGICAL IMPLICATIONS

International Nuclear Information System (INIS)

Ho, Shirley; White, Martin; Schlegel, David J.; Seljak, Uros; Reid, Beth; Cuesta, Antonio; Padmanabhan, Nikhil; Seo, Hee-Jong; De Putter, Roland; Ross, Ashley J.; Percival, Will J.; Saito, Shun; Schlafly, Eddie; Hernández-Monteagudo, Carlos; Sánchez, Ariel G.; Blanton, Michael; Skibba, Ramin; Schneider, Don; Mena, Olga; Viel, Matteo

2012-01-01

The Sloan Digital Sky Survey (SDSS) surveyed 14,555 deg 2 , and delivered over a trillion pixels of imaging data. We present a study of galaxy clustering using 900,000 luminous galaxies with photometric redshifts, spanning between z = 0.45 and z = 0.65, constructed from the SDSS using methods described in Ross et al. This data set spans 11,000 deg 2 and probes a volume of 3 h –3 Gpc 3 , making it the largest volume ever used for galaxy clustering measurements. We describe in detail the construction of the survey window function and various systematics affecting our measurement. With such a large volume, high-precision cosmological constraints can be obtained given careful control and understanding of the observational systematics. We present a novel treatment of the observational systematics and its applications to the clustering signals from the data set. In this paper, we measure the angular clustering using an optimal quadratic estimator at four redshift slices with an accuracy of ∼15%, with a bin size of δ l = 10 on scales of the baryon acoustic oscillations (BAOs; at l ∼ 40-400). We also apply corrections to the power spectra due to systematics and derive cosmological constraints using the full shape of the power spectra. For a flat ΛCDM model, when combined with cosmic microwave background Wilkinson Microwave Anisotropy Probe 7 (WMAP7) and H 0 constraints from using 600 Cepheids observed by Wide Field Camera 3 (WFC3; HST), we find Ω Λ = 0.73 ± 0.019 and H 0 to be 70.5 ± 1.6 s –1 Mpc –1 km. For an open ΛCDM model, when combined with WMAP7 + HST, we find Ω K = 0.0035 ± 0.0054, improved over WMAP7+HST alone by 40%. For a wCDM model, when combined with WMAP7+HST+SN, we find w = –1.071 ± 0.078, and H 0 to be 71.3 ± 1.7 s –1 Mpc –1 km, which is competitive with the latest large-scale structure constraints from large spectroscopic surveys such as the SDSS Data Release 7 (DR7) and WiggleZ. We also find that systematic-corrected power

DigiNotar: Dissecting the First Dutch Digital Disaster

Directory of Open Access Journals (Sweden)

Nicole S. van der Meulen

2013-01-01

Full Text Available In the middle of the night on September 2, 2011, the Dutch Minister of the Interior and Kingdom Relations held an emergency press conference. DigiNotar, a Certificate Authority (CA, had been electronically ‘broken into’ and as a result intruders had managed to generate falsified certificates. As a CA, DigiNotar issued digital certificates to secure digital communication, but as a result of the breach the authenticity of such certificates could no longer be verified. The Dutch government subsequently revoked its trust in all certificates issued by DigiNotar. This was the beginning of the first digital disaster in the Netherlands. As a pioneering disaster, this article focuses on the implications of DigiNotar as a vital case study for future scenarios of digital disaster management. The main focus of this article is on the underlying ‘weaknesses’ of the DigiNotar incident, which allowed the situation to evolve from a problem into a disaster. These include lack of oversight, lack of security attention and risk awareness and the absence of an effective mitigation strategy. By identifying and subsequently analyzing the underlying problems, this article aims to demonstrate how future situations can be better contained if sufficient attention is granted to these factors and subsequent changes are introduced.

Three years of digital photogrammetry at CERN

International Nuclear Information System (INIS)

Gayde, J.Ch.; Lasseur, Ch.

1999-01-01

The LHC (Large Hadron Collider) is the new particle accelerator project at CERN (European Laboratory for Particle Physics) in Geneva. It will be a 27 km long accelerator made of superconducting magnets. Four big physics detectors: ALICE, ATLAS, CMS, LHC-B, will be installed at four points around it. With this project, new survey requirements appear together with new spatial and time scale constraints. In order to respond to the demand, the CERN Positioning Metrology Group decided to expand its tool box by buying digital photogrammetric equipment three years ago. Basically this equipment consist of Kodak DCS460 cameras and of the Rollei-CDW (Close-range Digital Workstation) software. This system has been used quite extensively since its purchase. The next chapters illustrate the reasons for the choice of the digital photogrammetry tool at CERN and the evolution of its use. Some adapted tooling is also described below. (authors)

The B3-VLA CSS sample. VIII. New optical identifications from the Sloan Digital Sky Survey The ultraviolet-optical spectral energy distribution of the young radio sources

Science.gov (United States)

Fanti, C.; Fanti, R.; Zanichelli, A.; Dallacasa, D.; Stanghellini, C.

2011-04-01

Context. Compact steep-spectrum radio sources and giga-hertz peaked spectrum radio sources (CSS/GPS) are generally considered to be mostly young radio sources. In recent years we studied at many wavelengths a sample of these objects selected from the B3-VLA catalog: the B3-VLA CSS sample. Only ≈60% of the sources were optically identified. Aims: We aim to increase the number of optical identifications and study the properties of the host galaxies of young radio sources. Methods: We cross-correlated the CSS B3-VLA sample with the Sloan Digital Sky Survey (SDSS), DR7, and complemented the SDSS photometry with available GALEX (DR 4/5 and 6) and near-IR data from UKIRT and 2MASS. Results: We obtained new identifications and photometric redshifts for eight faint galaxies and for one quasar and two quasar candidates. Overall we have 27 galaxies with SDSS photometry in five bands, for which we derived the ultraviolet-optical spectral energy distribution (UV-O-SED). We extended our investigation to additional CSS/GPS selected from the literature. Most of the galaxies show an excess of ultra-violet (UV) radiation compared with the UV-O-SED of local radio-quiet ellipticals. We found a strong dependence of the UV excess on redshift and analyzed it assuming that it is generated either from the nucleus (hidden quasar) or from a young stellar population (YSP). We also compare the UV-O-SEDs of our CSS/GPS sources with those of a selection of large size (LSO) powerful radio sources from the literature. Conclusions: If the major process of the UV excess is caused by a YSP, our conclusion is that it is the result of the merger process that also triggered the onset of the radio source with some time delay. We do not see evidence for a major contribution from a YSP triggered by the radio sources itself. Appendices A-G are only available in electronic form at http://www.aanda.org

The prevention and eradication of smallpox: a commentary on Sloane (1755) ‘An account of inoculation’

Science.gov (United States)

Weiss, Robin A.; Esparza, José

2015-01-01

Sir Hans Sloane's account of inoculation as a means to protect against smallpox followed several earlier articles published in Philosophical Transactions on this procedure. Inoculation (also called ‘variolation’) involved the introduction of small amounts of infectious material from smallpox vesicles into the skin of healthy subjects, with the goal of inducing mild symptoms that would result in protection against the more severe naturally acquired disease. It began to be practised in England in 1721 thanks to the efforts of Lady Mary Wortley Montagu who influenced Sloane to promote its use, including the inoculation of the royal family's children. When Edward Jenner's inoculation with the cow pox (‘vaccination’) followed 75 years later as a safer yet equally effective procedure, the scene was set for the eventual control of smallpox epidemics culminating in the worldwide eradication of smallpox in 1977, officially proclaimed by WHO in 1980. Here, we discuss the significance of variolation and vaccination with respect to scientific, public health and ethical controversies concerning these ‘weapons of mass protection’. This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society. PMID:25750241

First-Year Maternal Employment and Child Development in the First Seven Years.

Science.gov (United States)

Brooks-Gunn, Jeanne; Han, Wen-Jui; Waldfogel, Jane

2010-08-01

Using data from the first 2 phases of the NICHD Study of Early Child Care, we examine the links between maternal employment in the first 12 months of life and cognitive, social, and emotional outcomes for children at age 3, age 4½, and first grade. Drawing on theory and prior research from developmental psychology as well as economics and sociology, we address three main questions. First, what associations exist between first-year maternal employment and cognitive, social, and emotional outcomes for children over the first seven years of life? Second, to what extent do any such associations vary by the child's gender and temperament, or the mother's occupation? Third, to what extent do mother's earnings, the home environment (maternal depressive symptoms, sensitivity, and HOME scores), and the type and quality of child care mediate or offset any associations between first-year employment and child outcomes, and what is the net effect of first-year maternal employment once these factors are taken into account? We compare families in which mothers worked full time (55%), part time (23%), or did not work (22%) in the first year for non-Hispanic white children (N=900) and for African-American children (N=113). Comparisons are also made taking into account the timing of mothers' employment within the first year. A rich set of control variables are included. OLS and SEM analyses are constructed. With regard to cognitive outcomes, first, we find that full-time maternal employment in the first 12 months of life (but not part-time employment) is associated with significantly lower scores on some, but not all, measures of cognitive development at age 3, 4 ½, and first grade for non-Hispanic white children, but with no significant associations for the small sample of African-American children Part-time employment in the first year is associated with higher scores than full-time employment for some measures. Employment in the second and third year of life is not associated

A Personal Reflection on the History of Radiation Oncology at Memorial Sloan-Kettering Cancer Center

International Nuclear Information System (INIS)

Chu, Florence C.H.

2011-01-01

Purpose: To provide a historical and personal narrative of the development of radiation oncology at Memorial Sloan-Kettering Cancer Center (MSKCC), from its founding more than 100 years ago to the present day. Methods and Materials: Historical sources include the Archives of MSKCC, publications by members of MSKCC, the author's personal records and recollections, and her communications with former colleagues, particularly Dr. Basil Hilaris, Dr. Zvi Fuks, and Dr. Beryl McCormick. Conclusions: The author, who spent 38 years at MSKCC, presents the challenges and triumphs of MSKCC's Radiation Oncology Department and details MSKCC's breakthroughs in radiation oncology. She also describes MSKCC's involvement in the founding of the American Society for Therapeutic Radiology and Oncology.

Deep learning approach for classifying, detecting and predicting photometric redshifts of quasars in the Sloan Digital Sky Survey stripe 82

Science.gov (United States)

Pasquet-Itam, J.; Pasquet, J.

2018-04-01

We have applied a convolutional neural network (CNN) to classify and detect quasars in the Sloan Digital Sky Survey Stripe 82 and also to predict the photometric redshifts of quasars. The network takes the variability of objects into account by converting light curves into images. The width of the images, noted w, corresponds to the five magnitudes ugriz and the height of the images, noted h, represents the date of the observation. The CNN provides good results since its precision is 0.988 for a recall of 0.90, compared to a precision of 0.985 for the same recall with a random forest classifier. Moreover 175 new quasar candidates are found with the CNN considering a fixed recall of 0.97. The combination of probabilities given by the CNN and the random forest makes good performance even better with a precision of 0.99 for a recall of 0.90. For the redshift predictions, the CNN presents excellent results which are higher than those obtained with a feature extraction step and different classifiers (a K-nearest-neighbors, a support vector machine, a random forest and a Gaussian process classifier). Indeed, the accuracy of the CNN within |Δz| < 0.1 can reach 78.09%, within |Δz| < 0.2 reaches 86.15%, within |Δz| < 0.3 reaches 91.2% and the value of root mean square (rms) is 0.359. The performance of the KNN decreases for the three |Δz| regions, since within the accuracy of |Δz| < 0.1, |Δz| < 0.2, and |Δz| < 0.3 is 73.72%, 82.46%, and 90.09% respectively, and the value of rms amounts to 0.395. So the CNN successfully reduces the dispersion and the catastrophic redshifts of quasars. This new method is very promising for the future of big databases such as the Large Synoptic Survey Telescope. A table of the candidates is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/611/A97

THE MASSIVE DISTANT CLUSTERS OF WISE SURVEY: THE FIRST DISTANT GALAXY CLUSTER DISCOVERED BY WISE

International Nuclear Information System (INIS)

Gettings, Daniel P.; Gonzalez, Anthony H.; Mancone, Conor; Stanford, S. Adam; Eisenhardt, Peter R. M.; Stern, Daniel; Brodwin, Mark; Zeimann, Gregory R.; Masci, Frank J.; Papovich, Casey; Tanaka, Ichi; Wright, Edward L.

2012-01-01

We present spectroscopic confirmation of a z = 0.99 galaxy cluster discovered using data from the Wide-field Infrared Survey Explorer (WISE). This is the first z ∼ 1 cluster candidate from the Massive Distant Clusters of WISE Survey to be confirmed. It was selected as an overdensity of probable z ∼> 1 sources using a combination of WISE and Sloan Digital Sky Survey DR8 photometric catalogs. Deeper follow-up imaging data from Subaru and WIYN reveal the cluster to be a rich system of galaxies, and multi-object spectroscopic observations from Keck confirm five cluster members at z = 0.99. The detection and confirmation of this cluster represents a first step toward constructing a uniformly selected sample of distant, high-mass galaxy clusters over the full extragalactic sky using WISE data.

CLUSTERING OF SLOAN DIGITAL SKY SURVEY III PHOTOMETRIC LUMINOUS GALAXIES: THE MEASUREMENT, SYSTEMATICS, AND COSMOLOGICAL IMPLICATIONS

Energy Technology Data Exchange (ETDEWEB)

Ho, Shirley; White, Martin; Schlegel, David J.; Seljak, Uros; Reid, Beth [Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, MS 50R-5045, Berkeley, CA 94720 (United States); Cuesta, Antonio; Padmanabhan, Nikhil [Yale Center for Astronomy and Astrophysics, Yale University, New Haven, CT 06511 (United States); Seo, Hee-Jong [Berkeley Center for Cosmological Physics, LBL and Department of Physics, University of California, Berkeley, CA 94720 (United States); De Putter, Roland [ICC, University of Barcelona (IEEC-UB), Marti i Franques 1, E-08028 Barcelona (Spain); Ross, Ashley J.; Percival, Will J. [Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth PO1 3FX (United Kingdom); Saito, Shun [Department of Astronomy, University of California Berkeley, CA (United States); Schlafly, Eddie [Department of Astronomy, Harvard University, 60 Garden St. MS 20, Cambridge, MA 02138 (United States); Hernandez-Monteagudo, Carlos [Centro de Estudios de Fisica del Cosmos de Aragon (CEFCA), Plaza de San Juan 1, planta 2, E-44001 Teruel (Spain); Sanchez, Ariel G. [Max-Planck-Institut fuer Extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching (Germany); Blanton, Michael [Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Skibba, Ramin [Steward Observatory, University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States); Schneider, Don [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Mena, Olga [Instituto de Fisica Corpuscular, Universidad de Valencia-CSIC (Spain); Viel, Matteo, E-mail: cwho@lbl.gov [INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, I-34131 Trieste (Italy); and others

2012-12-10

The Sloan Digital Sky Survey (SDSS) surveyed 14,555 deg{sup 2}, and delivered over a trillion pixels of imaging data. We present a study of galaxy clustering using 900,000 luminous galaxies with photometric redshifts, spanning between z = 0.45 and z = 0.65, constructed from the SDSS using methods described in Ross et al. This data set spans 11,000 deg{sup 2} and probes a volume of 3 h {sup -3} Gpc{sup 3}, making it the largest volume ever used for galaxy clustering measurements. We describe in detail the construction of the survey window function and various systematics affecting our measurement. With such a large volume, high-precision cosmological constraints can be obtained given careful control and understanding of the observational systematics. We present a novel treatment of the observational systematics and its applications to the clustering signals from the data set. In this paper, we measure the angular clustering using an optimal quadratic estimator at four redshift slices with an accuracy of {approx}15%, with a bin size of {delta}{sub l} = 10 on scales of the baryon acoustic oscillations (BAOs; at l {approx} 40-400). We also apply corrections to the power spectra due to systematics and derive cosmological constraints using the full shape of the power spectra. For a flat {Lambda}CDM model, when combined with cosmic microwave background Wilkinson Microwave Anisotropy Probe 7 (WMAP7) and H{sub 0} constraints from using 600 Cepheids observed by Wide Field Camera 3 (WFC3; HST), we find {Omega}{sub {Lambda}} = 0.73 {+-} 0.019 and H{sub 0} to be 70.5 {+-} 1.6 s{sup -1} Mpc{sup -1} km. For an open {Lambda}CDM model, when combined with WMAP7 + HST, we find {Omega}{sub K} = 0.0035 {+-} 0.0054, improved over WMAP7+HST alone by 40%. For a wCDM model, when combined with WMAP7+HST+SN, we find w = -1.071 {+-} 0.078, and H{sub 0} to be 71.3 {+-} 1.7 s{sup -1} Mpc{sup -1} km, which is competitive with the latest large-scale structure constraints from large spectroscopic

The 150th - Year Watershed - a Secure Digital Repository Created ...

African Journals Online (AJOL)

The narrative is based on the author's experience and involvement in the management of Standard Bank Heritage Centre over a period of years. It is concluded that while the journey from paper to digital environment proved successful so far at Standard Bank, the digital world remains problematic especially with regard to ...

A PRECISION MULTI-BAND TWO-EPOCH PHOTOMETRIC CATALOG OF 44 MILLION SOURCES IN THE NORTHERN SKY FROM A COMBINATION OF THE USNO-B AND SLOAN DIGITAL SKY SURVEY CATALOGS

International Nuclear Information System (INIS)

Madsen, G. J.; Gaensler, B. M.

2013-01-01

A key science driver for the next generation of wide-field optical and radio surveys is the exploration of the time variable sky. These surveys will have unprecedented sensitivity and areal coverage, but will be limited in their ability to detect variability on time scales longer than the lifetime of the surveys. We present a new precision, multi-epoch photometric catalog that spans 60 yr by combining the US Naval Observatory-B (USNO-B) and Sloan Digital Sky Survey (SDSS) Data Release 9 (DR9) catalogs. We recalibrate the photometry of the original USNO-B catalog and create a catalog with two epochs of photometry in up to five different bands for 43,647,887 optical point sources that lie in the DR9 footprint of the northern sky. The recalibrated objects span a magnitude range 14 ≲ m ≲ 20 and are accurate to ≈0.1 mag. We minimize the presence of spurious objects and those with inaccurate magnitudes by identifying and removing several sources of systematic errors in the two originating catalogs, with a focus on spurious objects that exhibit large apparent magnitude variations. After accounting for these effects, we find ≈250,000 stars and quasars that show significant (≥4σ) changes in brightness between the USNO-B and SDSS DR9 epochs. We discuss the historical value of the catalog and its application to the study of long time scale, large amplitude variable stars and quasars

Digital Divides and the 'First Mile': Framing First Nations Broadband Development in Canada

Directory of Open Access Journals (Sweden)

Rob McMahon

2011-05-01

Full Text Available Across Canada, rural and remote First Nations face a significant 'digital divide'. As self-determining autonomous nations in Canada, these communities are building broadband systems to deliver public services to their members and residents. To address this challenge, First Nations are working towards a variety of innovative, locally driven broadband development initiatives. This paper contributes a theoretical discussion that frames our understanding of these initiatives by drawing on the paradigm of the 'First Mile' (Paisley & Richardson, 1998. We argue that broadband development policy in Canada must be re-framed to address the specific needs of First Nations. The First Mile position foregrounds community-based involvement, control, and ownership: a consideration we suggest has particular resonance for First Nations. This is because it holds potential to move beyond the historical context of paternalistic, colonial-derived development policies, in the context of broadband systems development. We argue First Nations broadband projects offer on-the-ground examples of a First Mile approach, and call for more research in this area.

Digitalization in radiology--6 years in the St. Elisabeth Oncology Institute.

Science.gov (United States)

Valkovic, L; Lehotska, V; Magula, J; Tothova, L

2008-01-01

To determine advantages and specific problems of film-free digital hospital focused on radiology department. In the St. Elisabeth Oncology Institute in Bratislava we have more than 6-year experience with digital modalities and the PACS system. During this period many difficulties occurred and are expected to rise with an increasing number of digital modalities. Statistical evaluation of a 6-year period in numerous graphs and schemes. The amount of data can be seen in graphs, which show the amount of examinations and data volume from different modalities for specific time period to October 2007 and present volumes and increase of data amount in megabytes (MB) in the last 6 years. Despite of systematic capacity increase it is a long-term archiving and economical problem. It is crucial to solve the daily amount of data, backup copies, type of archiving media, and priority of data accessibility (Tab. 1, Fig. 5, Ref. 9). Full Text (Free, PDF) www.bmj.sk.

Contemporary computational mathematics a celebration of the 80th birthday of Ian Sloan

CERN Document Server

Kuo, Frances; Woźniakowski, Henryk

2018-01-01

This book is a tribute to Professor Ian Hugh Sloan on the occasion of his 80th birthday. It consists of nearly 60 articles written by international leaders in a diverse range of areas in contemporary computational mathematics. These papers highlight the impact and many achievements of Professor Sloan in his distinguished academic career. The book also presents state of the art knowledge in many computational fields such as quasi-Monte Carlo and Monte Carlo methods for multivariate integration, multi-level methods, finite element methods, uncertainty quantification, spherical designs and integration on the sphere, approximation and interpolation of multivariate functions, oscillatory integrals, and in general in information-based complexity and tractability, as well as in a range of other topics. The book also tells the life story of the renowned mathematician, family man, colleague and friend, who has been an inspiration to many of us. The reader may especially enjoy the story from the perspective of his fami...

Panchromatic properties of 99 000 galaxies detected by SDSS, and (some by) ROSAT, GALEX, 2MASS, IRAS, GB6, FIRST, NVSS and WENSS surveys

NARCIS (Netherlands)

Obric, M.; Ivezic, Z.; Best, P. N.; Lupton, R. H.; Tremonti, C.; Brinchmann, J.; Agueeros, M. A.; Knapp, G. R.; Gunn, J. E.; Rockosi, C. M.; Schlegel, D.; Finkbeiner, D.; Gacesa, M.; Smolcic, V.; Anderson, S. F.; Voges, W.; Juric, M.; Siverd, R. J.; Steinhardt, W.; Jagoda, A. S.; Blanton, M. R.; Schneider, D. P.

2006-01-01

We discuss the panchromatic properties of 99 088 galaxies selected from the Sloan Digital Sky Survey (SDSS) Data Release 1 'main' spectroscopic sample ( a flux-limited sample for 1360 deg(2)). These galaxies are positionally matched to sources detected by ROSAT, Galaxy Evolution Explorer (GALEX),

Searches for new Milky Way satellites from the first two years of data of the Subaru/Hyper Suprime-Cam survey: Discovery of Cetus III

Science.gov (United States)

Homma, Daisuke; Chiba, Masashi; Okamoto, Sakurako; Komiyama, Yutaka; Tanaka, Masayuki; Tanaka, Mikito; Ishigaki, Miho N.; Hayashi, Kohei; Arimoto, Nobuo; Garmilla, José A.; Lupton, Robert H.; Strauss, Michael A.; Miyazaki, Satoshi; Wang, Shiang-Yu; Murayama, Hitoshi

2018-01-01

We present the results from a search for new Milky Way (MW) satellites from the first two years of data from the Hyper Suprime-Cam (HSC) Subaru Strategic Program (SSP) ˜300 deg2 and report the discovery of a highly compelling ultra-faint dwarf galaxy candidate in Cetus. This is the second ultra-faint dwarf we have discovered after Virgo I reported in our previous paper. This satellite, Cetus III, has been identified as a statistically significant (10.7 σ) spatial overdensity of star-like objects, which are selected from a relevant isochrone filter designed for a metal-poor and old stellar population. This stellar system is located at a heliocentric distance of 251^{+24}_{-11}kpc with a most likely absolute magnitude of MV = -2.4 ± 0.6 mag estimated from a Monte Carlo analysis. Cetus III is extended with a half-light radius of r_h = 90^{+42}_{-17}pc, suggesting that this is a faint dwarf satellite in the MW located beyond the detection limit of the Sloan Digital Sky Survey. Further spectroscopic studies are needed to assess the nature of this stellar system. We also revisit and update the parameters for Virgo I, finding M_V = -0.33^{+0.75}_{-0.87}mag and r_h = 47^{+19}_{-13}pc. Using simulations of Λ-dominated cold dark matter models, we predict that we should find one or two new MW satellites from ˜300 deg2 HSC-SSP data, in rough agreement with the discovery rate so far. The further survey and completion of HSC-SSP over ˜1400 deg2 will provide robust insights into the missing satellites problem.

Can the periodic spectral modulations observed in 236 Sloan Sky Survey stars be due to dark matter effects?

Science.gov (United States)

Tamburini, Fabrizio; Licata, Ignazio

2017-09-01

The search for dark matter (DM) is one of the most active and challenging areas of current research. Possible DM candidates are ultralight fields such as axions and weak interacting massive particles (WIMPs). Axions piled up in the center of stars are supposed to generate matter/DM configurations with oscillating geometries at a very rapid frequency, which is a multiple of the axion mass m B (Brito et al (2015); Brito et al (2016)). Borra and Trottier (2016) recently found peculiar ultrafast periodic spectral modulations in 236 main sequence stars in the sample of 2.5 million spectra of galactic halo stars of the Sloan Digital Sky Survey (˜1% of main sequence stars in the F-K spectral range) that were interpreted as optical signals from extraterrestrial civilizations, suggesting them as possible candidates for the search for extraterrestrial intelligence (SETI) program. We argue, instead, that this could be the first indirect evidence of bosonic axion-like DM fields inside main sequence stars, with a stable radiative nucleus, where a stable DM core can be hosted. These oscillations were not observed in earlier stellar spectral classes probably because of the impossibility of starting a stable oscillatory regime due to the presence of chaotic motions in their convective nuclei. The axion mass values, (50< {m}B< 2.4× {10}3) μ {eV}, obtained from the frequency range observed by Borra and Trottier, (0.6070< f< 0.6077) THz, agree with the recent theoretical results from high-temperature lattice quantum chromodynamics (Borsanyi et al (2016); Borsanyi et al (2016b)).

The Sloan-C Pillars and Boundary Objects As a Framework for Evaluating Blended Learning

Science.gov (United States)

Laumakis, Mark; Graham, Charles; Dziuban, Chuck

2009-01-01

The authors contend that blended learning represents a boundary object; a construct that brings together constituencies from a variety of backgrounds with each of these cohorts defining the object somewhat differently. The Sloan-C Pillars (learning effectiveness, access, cost effectiveness, student satisfaction, and faculty satisfaction) provide…

Analyzing the Bitcoin Network: The First Four Years

Directory of Open Access Journals (Sweden)

Matthias Lischke

2016-03-01

Full Text Available In this explorative study, we examine the economy and transaction network of the decentralized digital currency Bitcoin during the first four years of its existence. The objective is to develop insights into the evolution of the Bitcoin economy during this period. For this, we establish and analyze a novel integrated dataset that enriches data from the Bitcoin blockchain with off-network data such as business categories and geo-locations. Our analyses reveal the major Bitcoin businesses and markets. Our results also give insights on the business distribution by countries and how businesses evolve over time. We also show that there is a gambling network that features many very small transactions. Furthermore, regional differences in the adoption and business distribution could be found. In the network analysis, the small world phenomenon is investigated and confirmed for several subgraphs of the Bitcoin network.

Risk factors for bowel dysfunction after sphincter-preserving rectal cancer surgery: a prospective study using the Memorial Sloan Kettering Cancer Center bowel function instrument.

Science.gov (United States)

Ihn, Myong Hoon; Kang, Sung-Bum; Kim, Duck-Woo; Oh, Heung-Kwon; Lee, Soo Young; Hong, Sa Min

2014-08-01

Until recently, no studies have prospectively evaluated bowel function after sphincter-preserving surgery for rectal cancer with the use of a validated bowel function scoring system. The aim of this study was to investigate possible risk factors for altered bowel function after sphincter-preserving surgery. This was a prospective study. The study was conducted between January 2006 and May 2012 at the authors' institution. Patients who underwent sphincter-preserving rectal cancer surgery were recruited. Bowel function was assessed 1 day before (baseline) and at 1 year after sphincter-preserving surgery or temporary ileostomy takedown with the use of the Memorial Sloan Kettering Cancer Center questionnaire. Multivariable analysis was performed to identify the factors associated with altered bowel function after surgery. Overall, 266 patients were eligible for the analysis. The tumor was located in the upper, middle, and lower rectum in 68 (25.5%), 113 (42.5%), and 85 (32.0%) patients. Intersphincteric resection and temporary ileostomy were performed in 18 (6.8%) and 129 (48.5%) patients. The mean Memorial Sloan Kettering Cancer Center score was 64.5 ± 7.6 at 1 year after sphincter-preserving surgery or temporary ileostomy takedown. The Memorial Sloan Kettering Cancer Center score decreased in 163/266 patients (61.3%) between baseline and 1 year after surgery. Tumor location (p = 0.01), operative method (p = 0.03), anastomotic type (p = 0.01), and temporary ileostomy (p = 0.01) were associated with altered bowel function after sphincter-preserving surgery in univariate analyses. In multivariable analysis, only tumor location was independently associated with impaired bowel function after sphincter-preserving rectal cancer surgery. This study was limited by its nonrandomized design and the lack of measurement before preoperative chemoradiotherapy. We suggest that preoperative counseling should be implemented to inform patients of the risk of bowel dysfunction

Mapping the Sloan Digital Sky Survey's Global Impact

Science.gov (United States)

Chen, Chaomei; Zhang, Jian; Vogeley, Michael S.

2009-07-01

The scientific capacity of a country is essential in todayâ's increasingly globalized science and technology ecosystem. Scientific capacity has four increasingly advanced levels of capabilities: absorbing, applying, creating, and retaining scientific knowledge. Moving to a advanced level requires additional skills and training. For example, it requires more specialized skills to apply scientific knowledge than to absorb knowledge. Similarly, making new discoveries requires more knowledge than applying existing procedures. Research has shown the importance of addressing specific, local problems while tapping into globally available expertise and resources. Accessing scientific knowledge is the first step towards absorbing knowledge. Low-income countries have increased their access to scientific literature on the Internet, but to what extent has this access led to more advanced levels of scientific capacity? Interdisciplinary and international collaboration may hold the key to creating and retaining knowledge. For example, creative ideas tend to be associated with inspirations originated from a diverse range of perspectives On the other hand, not all collaborations are productive. Assessing global science and technology needs to address both successes and failures and reasons behind them.

The stellar initial mass function of early-type galaxies from low to high stellar velocity dispersion: homogeneous analysis of ATLAS3D and Sloan Lens ACS galaxies

Science.gov (United States)

Posacki, Silvia; Cappellari, Michele; Treu, Tommaso; Pellegrini, Silvia; Ciotti, Luca

2015-01-01

We present an investigation about the shape of the initial mass function (IMF) of early-type galaxies (ETGs), based on a joint lensing and dynamical analysis, and on stellar population synthesis models, for a sample of 55 lens ETGs identified by the Sloan Lens Advanced Camera for Surveys (SLACS). We construct axisymmetric dynamical models based on the Jeans equations which allow for orbital anisotropy and include a dark matter halo. The models reproduce in detail the observed Hubble Space Telescope photometry and are constrained by the total projected mass within the Einstein radius and the stellar velocity dispersion (σ) within the Sloan Digital Sky Survey fibres. Comparing the dynamically-derived stellar mass-to-light ratios (M*/L)dyn, obtained for an assumed halo slope ρh ∝ r-1, to the stellar population ones (M*/L)Salp, derived from full-spectrum fitting and assuming a Salpeter IMF, we infer the mass normalization of the IMF. Our results confirm the previous analysis by the SLACS team that the mass normalization of the IMF of high-σ galaxies is consistent on average with a Salpeter slope. Our study allows for a fully consistent study of the trend between IMF and σ for both the SLACS and atlas3D samples, which explore quite different σ ranges. The two samples are highly complementary, the first being essentially σ selected, and the latter volume-limited and nearly mass selected. We find that the two samples merge smoothly into a single trend of the form log α = (0.38 ± 0.04) × log (σe/200 km s-1) + ( - 0.06 ± 0.01), where α = (M*/L)dyn/(M*/L)Salp and σe is the luminosity averaged σ within one effective radius Re. This is consistent with a systematic variation of the IMF normalization from Kroupa to Salpeter in the interval σe ≈ 90-270 km s-1.

Shifting gears higher - digital slides in graduate education - 4 years experience at Semmelweis University

Directory of Open Access Journals (Sweden)

Molnár Béla

2010-11-01

Full Text Available Abstract Background The spreading of whole slide imaging or digital slide systems in pathology as an innovative technique seems to be unstoppable. Successful introduction of digital slides in education has played a crucial role to reach this level of acceptance. Practically speaking there is no university institute where digital materials are not built into pathology education. At the 1st. Department of Pathology and Experimental Cancer Research, Semmelweis University optical microscopes have been replaced and for four years only digital slides have been used in education. The aim of this paper is to summarize our experiences gathered with the installation of a fully digitized histology lab for graduate education. Methods We have installed a digital histology lab with 40 PCs, two slide servers - one for internal use and one with external internet access. We have digitized hundreds of slides and after 4 years we use a set of 126 slides during the pathology course. A Student satisfaction questionnaire and a Tutor satisfaction questionnaire have been designed, both to be completed voluntarily to have feed back from the users. The page load statistics of the external slide server were evaluated. Results The digital histology lab served ~900 students and ~1600 hours of histology practice. The questionnaires revealed high satisfaction with digital slides. The results also emphasize the importance of the tutors' attitude towards digital microscopy as a factor influencing the students' satisfaction. The constantly growing number of page downloads from the external server confirms this satisfaction and the acceptance of digital slides. Conclusions We are confident, and have showed as well, that digital slides have got numerous advantages over optical slides and are more suitable in education.

Digital learning programs - competition for the classical microscope?

Science.gov (United States)

Schmidt, Peter

2013-01-01

The development of digital media has been impressive in recent years which is also among the reason for their increasing use in academic teaching. This is especially true for teaching Anatomy and Histology in the first two years in medical and dental curricula. Modern digital technologies allow for efficient, affordable and easily accessible distribution of histological images in high quality. Microscopy depends almost exclusively on such images. Since 20 years numerous digital teaching systems have been developed for this purpose. Respective developments have changed the ways students acquire knowledge and prepare for exams. Teaching staff should adapt lectures, seminars and labs accordingly. As a first step, a collection of high resolution digital microscopic slides was made available for students at the Friedrich-Schiller-University in Jena. The aim of the present study was to evaluate the importance of conventional light microscopy and related technologies in current and future medical and dental education aswell. A survey was done among 172 medical and dental students at the Friedrich-Schiller-University Jena. 51% of students use now frequently new digital media for learning histology in contrast to 5% in the year 2000 [1]. Digital media including Internet, CD- based learning combined with social networks successfully compete with classical light microscopy.

Reflections on a digital upgrade

Energy Technology Data Exchange (ETDEWEB)

Tadjalli, M.

2013-07-01

Upon receiving US NRC's approval in 2010, the first RPS/ESPS digital upgrade using TELEPERM® XS technology was successfully installed in Spring of 2011 at the first Unit of a three-unit station, followed by the 2nd Unit installation in spring of 2012. Both Units' systems have been operating flawlessly since installation. After about two years of operation, a reflection on digital upgrades and lessons learned, from a vendor perspective, provides valuable insight for the commercial nuclear power industry.

The Stability of Values in the First Ten Years of the Career. Final Report.

Science.gov (United States)

Schein, Edgar H.

Forty-four alumni of the Sloan School of Management classes of 1961, 1962, and 1963 were followed up in 1973 by means of interviews and questionnaires to determine: (1) career paths followed; (2) value changes observed; and (3) relationships between value changes and career events. Careers were conceptualized in terms of "career anchors," five…

SDSS J2222+2745: A GRAVITATIONALLY LENSED SEXTUPLE QUASAR WITH A MAXIMUM IMAGE SEPARATION OF 15.''1 DISCOVERED IN THE SLOAN GIANT ARCS SURVEY

International Nuclear Information System (INIS)

Dahle, H.; Groeneboom, N.; Gladders, M. D.; Abramson, L. E.; Sharon, K.; Bayliss, M. B.; Wuyts, E.; Koester, B. P.; Brinckmann, T. E.; Kristensen, M. T.; Lindholmer, M. O.; Nielsen, A.; Krogager, J.-K.; Fynbo, J. P. U.

2013-01-01

We report the discovery of a unique gravitational lens system, SDSS J2222+2745, producing five spectroscopically confirmed images of a z s = 2.82 quasar lensed by a foreground galaxy cluster at z l = 0.49. We also present photometric and spectroscopic evidence for a sixth lensed image of the same quasar. The maximum separation between the quasar images is 15.''1. Both the large image separations and the high image multiplicity are in themselves rare among known lensed quasars, and observing the combination of these two factors is an exceptionally unlikely occurrence in present data sets. This is only the third known case of a quasar lensed by a cluster, and the only one with six images. The lens system was discovered in the course of the Sloan Giant Arcs Survey, in which we identify candidate lenses in the Sloan Digital Sky Survey and target these for follow-up and verification with the 2.56 m Nordic Optical Telescope. Multi-band photometry obtained over multiple epochs from 2011 September to 2012 September reveals significant variability at the ∼10%-30% level in some of the quasar images, indicating that measurements of the relative time delay between quasar images will be feasible. In this lens system, we also identify a bright (g = 21.5) giant arc corresponding to a strongly lensed background galaxy at z s = 2.30. We fit parametric models of the lens system, constrained by the redshift and positions of the quasar images and the redshift and position of the giant arc. The predicted time delays between different pairs of quasar images range from ∼100 days to ∼6 yr

Communicating with first year students; so many channels but is anyone listening? A Practice Report

Directory of Open Access Journals (Sweden)

Jason Lodge

2010-07-01

Full Text Available Communicating with first year students has become a far more complex prospect in the digital age. There is a lot of competition for limited attentional resources from media sources in almost endless channels. Getting important messages to students when there is so much competing information is a difficult prospect for academic and professional divisions of the university alike. Students’ preferences for these communication channels are not well understood and are constantly changing with the introduction of new technology. A first year group was surveyed about their use and preference for various sources of information. Students were generally positive about the use of social networking and other new online media but strongly preferred more established channels for official academic and administrative information. A discussion of the findings and recommendations follows.

Digital practices in everyday lives of 4 to 6 years old Romanian children

Directory of Open Access Journals (Sweden)

Gyöngyvér Tőkés

2016-12-01

Full Text Available The purpose of this study is to present some findings of a broader research called Digital literacy and multimodal practices of young children from Romania. The mentioned research was part of the EU COST Action IS1410 involving similar endeavours from over 30 countries (COST 2014; Bakó, 2016: p. 146. In our research we used several sources for data collection such as children and their parents, as well as kindergarten educators. We collected qualitative data using three methods: the visual method of drawing, semi-structured interviews and observation. In this study we present digital practices of 4 to 6 years old Romanian children based on interviews made with the children’s parents. We found similar results to other Romanian (Velicu, Mitarcă, 2016 and European (Chaudron, 2015 research such as: the access and use of digital technology is present but not dominant in the daily routines of Romanian young children; Romanian young children’s favourite digital devices are tablets and smartphones; Romanian young children’s familiar digital activities are watching YouTube videos, playing games, making or watching photos and videos about themselves and their families; Romanian young children learn the use of digital devices by observation and imitation, and through testing; the level of Romanian young children’s digital skills is basic; the digitally unexperienced Romanian parents are not supportive with children’s digital endeavours.

Digital pathology: DICOM-conform draft, testbed, and first results.

Science.gov (United States)

Zwönitzer, Ralf; Kalinski, Thomas; Hofmann, Harald; Roessner, Albert; Bernarding, Johannes

2007-09-01

Hospital information systems are state of the art nowadays. Therefore, Digital Pathology, also labelled as Virtual Microscopy, has gained increased attention. Triggered by radiology, standardized information models and workflows were world-wide defined based on DICOM. However, DICOM-conform integration of Digital Pathology into existing clinical information systems imposes new problems requiring specific solutions concerning the huge amount of data as well as the special structure of the data to be managed, transferred, and stored. We implemented a testbed to realize and evaluate the workflow of digitized slides from acquisition to archiving. The experiences led to the draft of a DICOM-conform information model that accounted for extensions, definitions, and technical requirements necessary to integrate digital pathology in a hospital-wide DICOM environment. Slides were digitized, compressed, and could be viewed remotely. Real-time transfer of the huge amount of data was optimized using streaming techniques. Compared to a recent discussion in the DICOM Working Group for Digital Pathology (WG26) our experiences led to a preference of a JPEG2000/JPIP-based streaming of the whole slide image. The results showed that digital pathology is feasible but strong efforts by users and vendors are still necessary to integrate Digital Pathology into existing information systems.

The Apache Point Observatory Galactic Evolution Experiment (APOGEE)

DEFF Research Database (Denmark)

Majewski, Steven R.; Schiavon, Ricardo P.; Frinchaboy, Peter M.

2017-01-01

The Apache Point Observatory Galactic Evolution Experiment (APOGEE), one of the programs in the Sloan Digital Sky Survey III (SDSS-III), has now completed its systematic, homogeneous spectroscopic survey sampling all major populations of the Milky Way. After a three-year observing campaign on the...

Historical photogrammetry: Bird's Paluxy River dinosaur chase sequence digitally reconstructed as it was prior to excavation 70 years ago.

Science.gov (United States)

Falkingham, Peter L; Bates, Karl T; Farlow, James O

2014-01-01

It is inevitable that some important specimens will become lost or damaged over time, conservation is therefore of vital importance. The Paluxy River dinosaur tracksite is among the most famous in the world. In 1940, Roland T. Bird described and excavated a portion of the site containing associated theropod and sauropod trackways. This excavated trackway was split up and housed in different institutions, and during the process a portion was lost or destroyed. We applied photogrammetric techniques to photographs taken by Bird over 70 years ago, before the trackway was removed, to digitally reconstruct the site as it was prior to excavation. The 3D digital model offers the opportunity to corroborate maps drawn by R.T. Bird when the tracksite was first described. More broadly, this work demonstrates the exciting potential for digitally recreating palaeontological, geological, or archaeological specimens that have been lost to science, but for which photographic documentation exists.

Analysis of first and second order binary quantized digital phase-locked loops for ideal and white Gaussian noise inputs

Science.gov (United States)

Blasche, P. R.

1980-01-01

Specific configurations of first and second order all digital phase locked loops are analyzed for both ideal and additive white gaussian noise inputs. In addition, a design for a hardware digital phase locked loop capable of either first or second order operation is presented along with appropriate experimental data obtained from testing of the hardware loop. All parameters chosen for the analysis and the design of the digital phase locked loop are consistent with an application to an Omega navigation receiver although neither the analysis nor the design are limited to this application.

Uncovering Young Children's Transformative Digital Game Play through the Exploration of Three-Year-Old Children's Cases

Science.gov (United States)

Huh, Youn Jung

2017-01-01

In contrast to studies focusing on digital games as learning tools, this study shows how young children use digital games as a means of facilitating spontaneous play in their everyday lives. This article highlights how 4 three-year-old children's play with digital games revealed their ability to create new forms of play by mixing their digital…

The use of ultrasonography and digital mammography in women under 40 years with symptomatic breast cancer: a 7-year Irish experience.

Science.gov (United States)

Redmond, C E; Healy, G M; Murphy, C F; O'Doherty, A; Foster, A

2017-02-01

Breast cancer in women under 40 years of age is rare and typically presents symptomatically. The optimal imaging modality for this patient group is controversial. Most women undergo ultrasonography with/without mammography. Young women typically have dense breasts, which can obscure the features of malignancy on film mammography, however, initial studies have suggested that digital mammography may have a more accurate diagnostic performance in younger women. Ultrasound generally performs well in this age group, although it is poor at detecting carcinoma in situ (DCIS). To evaluate the comparative diagnostic performance of ultrasonography and digital mammography in the initial diagnostic evaluation of women under 40 years of age with symptomatic breast cancer. Retrospective review of all women under the age of 40 years managed at our symptomatic breast cancer unit from January 2009 to December 2015. There were 120 patients that met the inclusion criteria for this study. The sensitivity of ultrasonography and digital mammography for breast cancer in this patient group was 95.8 and 87.5 %, respectively. The patients with a false negative mammographic examination were more likely to have dense breasts (p breast cancer in women under the age of 40 years, however, the results show that digital mammography has an important complimentary role in the comprehensive assessment of these patients, particularly in the diagnosis of DCIS.

Digital image intensifier radiography: first experiences with the DSI (Digital Spot Imaging)

International Nuclear Information System (INIS)

Rueckforth, J.; Wein, B.; Stargardt, A.; Guenther, R.W.

1995-01-01

We performed a comparative study of digitally and conventionally acquired images in gastrointestinal examinations. Radiation dose and spatial resolution were determined in a water phantom. In 676 examinations with either conventional or digital imaging (system: Diagnost 76, DSI) the number of images and the duration of the fluoroscopy time were compared. 101 examinations with digital as well as conventional documentation were evaluated by using 5 criteria describing the diagnostic performance. The entrance dose of the DSI is 12% to 36% of the film/screen system and the spatial resolution of the DSI may be better than that of a film/screen system with a speed of 200. The fluoroscopy time shows no significant difference between DSI and the film/screen technique. In 2 of 4 examination modes significantly more images were produced by the DSI. With exception of the criterion of edge sharpness, DSI yields a significantly inferior assessment compared with the film/screen technique. (orig./MG) [de

Actual concepts of digital PAC-spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Roeder, J., E-mail: j.roeder@tu-bs.de; Herden, C., E-mail: cherden@viewplus.de [Braunschweig University of Technology, Institute of Physical and Theoretical Chemistry (Germany); Gardner, J. A., E-mail: john.gardner@viewplus.com [Oregon State University (United States); Becker, K. D., E-mail: k-d.becker@tu-bs.de [Braunschweig University of Technology, Institute of Physical and Theoretical Chemistry (Germany); Uhrmacher, M., E-mail: muhrmac@gwdg.de; Hofsaess, H., E-mail: hhofsae@uni-goettingen.de [University of Goettingen, II. Institute of Physics (Germany)

2008-01-15

In conventional perturbed angular correlation (PAC)-spectroscopy huge amounts of events are processed by fast electronics. Modern digital signal processing devices and the improvement in the computer technology in recent years allow today digital PAC-spectrometer setups capable to perform software-based data processing with all the benefits of storage, repeatable data analysis under different limits, and easy switching between different isotopes. In this paper we discuss experiences and concepts of a first realized digital PAC-spectrometer, which will be rebuild at ISOLDE/CERN/Geneva.

Digital Immigrants and Digital Natives: Learning Business Informatics at Higher Educational Level

Directory of Open Access Journals (Sweden)

Suša Dalia

2014-09-01

Full Text Available Background: The term digital natives refer to those born since the 1980s and have been growing up surrounded by technology. On the other hand, digital immigrants are born before 1980s and learned how to use technology later in life. Objectives: Goal of the paper is to explore attitudes of digital native students on the course of Business Informatics at higher educational institutions (HEIs, and to compare them with attitudes of digital immigrants. Methods/Approach: The survey was conducted in 2014 using the sample of first-year Business Informatics students from the Faculty of Economics and Business in Zagreb, Croatia. Results were compared with a research conducted in 1998. Results: In comparison to an earlier research, digital natives perceive their level of competency in the subject of Business Informatics before teaching practices much higher compared to digital immigrants. However, there is still an increase in digital native students’ level of competency in the subject before and after teaching practices. Conclusions: The research confirms a shift from digital immigrants to digital natives who show high level of interest for Business Informatics course topics and find its utility very high. However, constant improvement of delivering knowledge is needed in order to keep these high levels.

Digital Tectonics

DEFF Research Database (Denmark)

Christiansen, Karl; Borup, Ruben; Søndergaard, Asbjørn

2014-01-01

Digital Tectonics treats the architectonical possibilities in digital generation of form and production. The publication is the first volume of a series, in which aspects of the strategic focus areas of the Aarhus School of Architecture will be disseminated.......Digital Tectonics treats the architectonical possibilities in digital generation of form and production. The publication is the first volume of a series, in which aspects of the strategic focus areas of the Aarhus School of Architecture will be disseminated....

Chronopolis Digital Preservation Network

Directory of Open Access Journals (Sweden)

David Minor

2010-07-01

Full Text Available The Chronopolis Digital Preservation Initiative, one of the Library of Congress’ latest efforts to collect and preserve at-risk digital information, has completed its first year of service as a multi-member partnership to meet the archival needs of a wide range of domains.Chronopolis is a digital preservation data grid framework developed by the San Diego Supercomputer Center (SDSC at UC San Diego, the UC San Diego Libraries (UCSDL, and their partners at the National Center for Atmospheric Research (NCAR in Colorado and the University of Maryland's Institute for Advanced Computer Studies (UMIACS.Chronopolis addresses a critical problem by providing a comprehensive model for the cyberinfrastructure of collection management, in which preserved intellectual capital is easily accessible, and research results, education material, and new knowledge can be incorporated smoothly over the long term. Integrating digital library, data grid, and persistent archive technologies, Chronopolis has created trusted environments that span academic institutions and research projects, with the goal of long-term digital preservation.A key goal of the Chronopolis project is to provide cross-domain collection sharing for long-term preservation. Using existing high-speed educational and research networks and mass-scale storage infrastructure investments, the partnership is leveraging the data storage capabilities at SDSC, NCAR, and UMIACS to provide a preservation data grid that emphasizes heterogeneous and highly redundant data storage systems.In this paper we will explore the major themes within Chronopolis, including:a The philosophy and theory behind a nationally federated data grid for preservation. b The core tools and technologies used in Chronopolis. c The metadata schema that is being developed within Chronopolis for all of the data elements. d Lessons learned from the first year of the project.e Next steps in digital preservation using Chronopolis: how we

Digital Humanities and networked digital media

DEFF Research Database (Denmark)

Finnemann, Niels Ole

2014-01-01

This article discusses digital humanities and the growing diversity of digital media, digital materials and digital methods. The first section describes the humanities computing tradition formed around the interpretation of computation as a rule-based process connected to a concept of digital...... materials centred on the digitisation of non-digital, finite works, corpora and oeuvres. The second section discusses “the big tent” of contemporary digital humanities. It is argued that there can be no unifying interpretation of digital humanities above the level of studying digital materials with the help...... of software-supported methods. This is so, in part, because of the complexity of the world and, in part, because digital media remain open to the projection of new epistemologies onto the functional architecture of these media. The third section discusses the heterogeneous character of digital materials...

Early reionization by decaying particles and cosmic microwave background radiation

International Nuclear Information System (INIS)

Kasuya, S.; Kawasaki, M.

2004-01-01

We study the reionization scenario in which ionizing UV photons emitted from decaying particle, in addition to usual contributions from stars and quasars, ionize the universe. It is found that the scenario is consistent with both the first year data of the Wilkinson Microwave Anisotropy Probe and the fact that the universe is not fully ionized until z∼6 as observed by Sloan Digital Sky Survey. Likelihood analysis revealed that rather broad parameter space can be chosen. This scenario will be discriminated by future observations, especially by the EE polarization power spectrum of cosmic microwave background radiation

The fall of the Northern Unicorn: Tangential motions in the Galactic Anti-centre with SDSS and Gaia

OpenAIRE

de Boer, T. J. L.; Belokurov, V.; Koposov, S. E.

2017-01-01

We present the first detailed study of the behaviour of the stellar proper motion across the entire Galactic Anti-centre area visible in the Sloan Digital Sky Survey data. We use recalibrated SDSS astrometry in combination with positions from {\\it Gaia} DR1 to provide tangential motion measurements with a systematic uncertainty $

Report from the research committee of digital imaging standardization in nuclear medicine

International Nuclear Information System (INIS)

Nakamura, Yutaka; Ise, Toshihide; Isetani, Osamu; Ichihara, Takashi; Ohya, Nobuyoshi; Kanaya, Shinichi; Fukuda, Toshio; Horii, Hitoshi.

1994-01-01

Since digital scintillation camera systems were developed in 1982, digital imaging is rapidly replacing analog imaging. During the first year, the research committee of digital imaging standardization has collected and analyzed basic data concerning digital examination equipment systems, display equipments, films, and hardware and software techniques to determine items required for the standardization of digital imaging. During the second year, it has done basic phantom studies to assess digital images and analyzed the results from both physical and visual viewpoints. On the basis of the outcome of the research committee's activities and the nationwide survey, the draft of digital imaging standardization in nuclear medicine has been presented. In this paper. the analytical data of the two-year survey, made by the research committee of digital imaging standardization, are presented. The descriptions are given under the following four items: (1) standardization digital examination techniques, (2) standardization of display techniques, (3) the count and pixel of digital images, and (4) standardization of digital imaging techniques. (N.K.)

Anarchic desires : deconstructing sexual and moral representations in Joe Orton's entertaining mr. sloane

OpenAIRE

Werner Almeida Alves

2007-01-01

A presente dissertação tem como objetivo apresentar uma leitura da peça Entertaining Mr. Sloane do dramaturgo inglês Joe Orton, investigando de que formas os artifícios literários são construídos para interromper as representações normativas sobre sexualidade e moralidade. Na obra de Orton, os comportamentos e discursos das personagens ignoram autoridades representativas de instituições que, como a família, trabalham para ratificar a noção de modos sexuais ligados à matrix heterossexual que c...

The new digital natives cutting the chord

CERN Document Server

Dingli, Alexei

2015-01-01

The first generation of Digital Natives (DNs) is now growing up.  However, these digital natives were rather late starters since; their exposure to computers started when they could master the mouse and the penetration of computers in educational institutions was still very low. Today, a new breed of digital natives is emerging.  This new breed includes those individuals who are being introduced from their first instances to the world of wireless devices. One year olds manage to master the intuitive touch interfaces of their tablets whilst sitting comfortably in their baby bouncers. The controller-less interfaces allow these children to interact with a machine in a way which was unconceivable below. Thus, our research investigated the paradigm shift between the different generations of digital natives. We analysed the way in which these two generations differ from each other and we explored how the world needs to change in order to harness the potential of these new digital natives.

Digital fibromas. Report of three cases

Directory of Open Access Journals (Sweden)

Patricia Chang

2017-07-01

Full Text Available Digital fibroma is a rare benign lesion that usually occurs during the first 2 years of life. It can be multiple, but it is usually a single lesion. If it grows large enough it can cause joint deformities or interfere with everyday activities. We report 3 cases of digital fibroma 2 in female patient and 1 in male patient due to its uncommon localization of fibromas.

Children under Five and Digital Technologies: Implications for Early Years Pedagogy

Science.gov (United States)

Palaiologou, Ioanna

2016-01-01

This project aimed to investigate the types of digital technologies children under the age of five are using at home and assess the possible implications for early years pedagogy. The research, carried out between 2010 and 2012, was based in four European countries: England, Greece, Malta and Luxemburg. A mixed methods approach was employed to…

A Survey of z>5.8 Quasars in the Sloan Digital Sky Survey. I. Discovery of Three New Quasars and the Spatial Density of Luminous Quasars at z~6

Science.gov (United States)

Fan, Xiaohui; Narayanan, Vijay K.; Lupton, Robert H.; Strauss, Michael A.; Knapp, Gillian R.; Becker, Robert H.; White, Richard L.; Pentericci, Laura; Leggett, S. K.; Haiman, Zoltán; Gunn, James E.; Ivezić, Željko; Schneider, Donald P.; Anderson, Scott F.; Brinkmann, J.; Bahcall, Neta A.; Connolly, Andrew J.; Csabai, István; Doi, Mamoru; Fukugita, Masataka; Geballe, Tom; Grebel, Eva K.; Harbeck, Daniel; Hennessy, Gregory; Lamb, Don Q.; Miknaitis, Gajus; Munn, Jeffrey A.; Nichol, Robert; Okamura, Sadanori; Pier, Jeffrey R.; Prada, Francisco; Richards, Gordon T.; Szalay, Alex; York, Donald G.

2001-12-01

We present the results from a survey of i-dropout objects selected from ~1550 deg2 of multicolor imaging data from the Sloan Digital Sky Survey to search for luminous quasars at z>~5.8. Objects with i*-z*>2.2 and z*0.90. The ARC 3.5 m spectrum of SDSSp J103027.10+052455.0 shows that over a range of ~300 Å immediately blueward of the Lyα emission, the average transmitted flux is only 0.003+/-0.020 times that of the continuum level, consistent with zero flux over a ~300 Å range of the Lyα forest region and suggesting a tentative detection of the complete Gunn-Peterson trough. The existence of strong metal lines in the quasar spectra suggests early metal enrichment in the quasar environment. The three new objects, together with the previously published z=5.8 quasar SDSSp J104433.04-012502.2, form a complete color-selected flux-limited sample at z>~5.8. We estimate the selection function of this sample, taking into account the estimated variations in the quasar spectral energy distribution, as well as observational photometric errors. We find that at z=6, the comoving density of luminous quasars at M1450Canada), CONICYT (Chile), the Australian Research Council (Australia), CNPq (Brazil), and CONICET (Argentina) on observations obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration, made possible by the generous financial support of the W. M. Keck Foundation; on observations obtained at the German-Spanish Astronomical Centre, Calar Alto Observatory, operated by the Max Planck Institute for Astronomy, Heidelberg, jointly with the Spanish National Commission for Astronomy; and on observations obtained at UKIRT, which is operated by the Joint Astronomy Centre on behalf of the UK Particle Physics and Astronomy Research Council.

The Eighth Data Release Of The Sloan Digital Sky Survey: First Data From SDSS-3

Science.gov (United States)

2011-04-01

of galaxies (Strauss et al. 2002; Eisenstein et al. 2001), quasars (Richards et al. 2002b), stars (Yanny et al. 2009), and other objects are selected...interlocking surveys; it is described in detail in a companion paper ( Eisenstein et al. 2011). In brief, these surveys are as follows. 1. SEGUE-2. This...algorithms were refined in various ways, as detailed in C. Rockosi et al. (2011, in preparation; see also Eisenstein et al. 2011). We summarize the

Does digital mammography suppose an advance in early diagnosis? Trends in performance indicators 6 years after digitalization.

Science.gov (United States)

Sala, Maria; Domingo, Laia; Macià, Francesc; Comas, Mercè; Burón, Andrea; Castells, Xavier

2015-03-01

To provide a complete evaluation of the long-term impact of full-field digital mammography (FFDM) on the improvement of early diagnosis in a population-based screening program. We included 82,961 screen-film mammograms (SFM) and 79,031 FFDM from women aged 50-69 screened biennially from 1995-2010 in Spain and followed-up to 2012. The first screening round of the program was excluded. Rates of cancer detection, interval cancer, tumoral characteristics and other quality indicators were compared between SFM and FFDM periods using the Chi-square test. Multivariate logistic regression models were fitted. Detection of ductal carcinoma in situ (DCIS) significantly increased with FFDM (0.05 % vs 0.09 %; p = 0.010), along with the proportion of small invasive cancers (Digitalization has supposed an improvement in early diagnosis because DCIS and small invasive cancers increased without a change in detection rate. Moreover, false-positive reduction without an increase in the interval cancer rate was confirmed.

THE SLOAN BRIGHT ARCS SURVEY: TEN STRONG GRAVITATIONAL LENSING CLUSTERS AND EVIDENCE OF OVERCONCENTRATION

Energy Technology Data Exchange (ETDEWEB)

Wiesner, Matthew P. [Department of Physics, Northern Illinois University, DeKalb, IL 60115 (United States); Lin, Huan; Allam, Sahar S.; Annis, James; Buckley-Geer, Elizabeth J.; Diehl, H. Thomas; Kubik, Donna; Kubo, Jeffrey M.; Tucker, Douglas [Center for Particle Astrophysics, Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States)

2012-12-10

We describe 10 strong lensing galaxy clusters of redshift 0.26 {<=} z {<=} 0.56 that were found in the Sloan Digital Sky Survey. We present measurements of richness (N{sub 200}), mass (M{sub 200}), and velocity dispersion for the clusters. We find that in order to use the mass-richness relation from Johnston et al., which was established at mean redshift of 0.25, it is necessary to scale measured richness values up by 1.47. Using this scaling, we find richness values for these clusters to be in the range of 22 {<=} N{sub 200} {<=} 317 and mass values to be in the range of 1 Multiplication-Sign 10{sup 14} h {sup -1} M{sub Sun} {<=} M{sub 200} {<=} 30 Multiplication-Sign 10{sup 14} h {sup -1} M{sub Sun }. We also present measurements of Einstein radius, mass, and velocity dispersion for the lensing systems. The Einstein radii ({theta}{sub E}) are all relatively small, with 5.''4 {<=} {theta}{sub E} {<=} 13''. Finally, we consider if there is evidence that our clusters are more concentrated than {Lambda}CDM would predict. We find that six of our clusters do not show evidence of overconcentration, while four of our clusters do. We note a correlation between overconcentration and mass, as the four clusters showing evidence of overconcentration are all lower-mass clusters. For the four lowest mass clusters the average value of the concentration parameter c{sub 200} is 11.6, while for the six higher-mass clusters the average value of c{sub 200} is 4.4. {Lambda}CDM would place c{sub 200} between 3.4 and 5.7.

Darnton's paradigm. Reflections on the social role of digital library

Directory of Open Access Journals (Sweden)

Andrea Capaccioni

2015-01-01

Full Text Available The interest in digital libraries began in the early nineties of the last century, particularly in the United States. At first the argument involved a few computer scientists and some librarian. However, after the first terminological uncertainties ("electronic" library, "virtual" library, etc., digital libraries have become an object of interdisciplinary study and today constitute a research field of LIS. Over the years there has been an evolution of topics and approaches. The earlier prevailing interest was in the management and technological aspects of digital libraries and then emerged the need to rediscover the role of digital libraries in society. This paper focuses in particular on the most recent international debate on the social value of the digital library.

Benford's law first significant digit and distribution distances for testing the reliability of financial reports in developing countries

Science.gov (United States)

Shi, Jing; Ausloos, Marcel; Zhu, Tingting

2018-02-01

We discuss a common suspicion about reported financial data, in 10 industrial sectors of the 6 so called "main developing countries" over the time interval [2000-2014]. These data are examined through Benford's law first significant digit and through distribution distances tests. It is shown that several visually anomalous data have to be a priori removed. Thereafter, the distributions much better follow the first digit significant law, indicating the usefulness of a Benford's law test from the research starting line. The same holds true for distance tests. A few outliers are pointed out.

Incorporating digital technologies into science classes

DEFF Research Database (Denmark)

Hilton, Annette; Hilton, Geoff

2013-01-01

in science. The first case study involved primary school students (12 years old) using digital video production to record and represent their learning in science. This study extended writing-to-learn approaches to include video production to learn. The second case study involved Year 11 chemistry students...... learning. There is a need for research that examines the ways in which digital technologies impact on teaching practices and learning outcomes. This paper describes case studies from two larger studies that examined ways in which digital technologies could be used to promote students’ understanding...... for students, including increased conceptual understanding, enhanced motivation and engagement, and increased representational competence. This paper reports on the classroom strategies and teaching resources used in each case, and describes the learning outcomes for the students involved and some...

Personal Digital Branding as a Professional Asset in the Digital Age.

Science.gov (United States)

Kleppinger, Courtney A; Cain, Jeff

2015-08-25

In recent years, society's rapid adoption of social media has made the boundary between professional and private life nearly indistinguishable. The literature provides guidance on how to demonstrate professionalism via social media platforms. Social media policies within health professions education tend to be legalistic in nature, serving primarily to highlight behaviors students should avoid. One missing element in social media literature is the concept of online invisibility. In this paper, we define personal digital branding, discuss the professional implications of choosing to abstain from social media use, and urge educators to recognize that the personal digital branding may be an emerging asset for young professionals in the twenty-first century.

Digital instrumentation and management of dead time: first results on a NaI well-type detector setup.

Science.gov (United States)

Censier, B; Bobin, C; Bouchard, J; Aubineau-Lanièce, I

2010-01-01

The LNE-LNHB is engaged in a development program on digital instrumentation, the first step being the instrumentation of a NaI well-type detector set-up. The prototype acquisition card and its technical specifications are presented together with the first comparison with the classical NIM-based acquisition chain, for counting rates up to 100 kcps. The digital instrumentation is shown to be counting-loss free in this range. This validates the main option adopted in this project, namely the implementation of an extending dead time with live-time measurement already successfully used in the MTR2 NIM module developed at LNE-LNHB. Copyright 2010. Published by Elsevier Ltd.

Why is digit ratio correlated to sports performance?

Science.gov (United States)

Kim, Tae Beom; Kim, Khae Hawn

2016-12-01

Second to fourth digit ratio is the ratio of second to fourth digit length. It has been known that digit ratio is sexually dimorphic in humans, such that males tend to have lower digit ratio (longer fourth digits relative to second digits) than females. Digit ratio is thought to be a biomarker of the balance between fetal testosterone (FT) and fetal estrogen (FE) in a relatively narrow developmental window at the end of the first trimester of pregnancy. On the contrary, the relationships between digit ratio and levels of sex steroids in adults are not clear. Most correlational studies between digit ratio and adult sex steroids have revealed that this association is statistically not significant. However, for many years, a lot of researches showed negative relationships between digit ratio and sports performance such as rugby, surfing, rowing, sprinting, endurance, and hand grip strength. Here, we discuss possible mechanisms about the relationships between digit ratio and sports performance.

The "first digit law" - A hypothesis on its possible impact on medicine and development aid.

Science.gov (United States)

Pollach, Gregor; Brunkhorst, Frank; Mipando, Mwapatsa; Namboya, Felix; Mndolo, Samson; Luiz, Thomas

2016-12-01

The "first digit law" or "Benford's law" is a mathematical distribution discovered by Simon Newcomb and Frank Benford. It states, that the probability of the leading number d (d∈{1,…,9}) in many natural datasets follows: P (d)=log 10 (d+1)-log 10 (d)=log 10 (1+1/d). It was successfully used through tax authorities and "forensic accounting" in order to detect fraud and other irregularities. Benfords law was almost neglected for its use outside financial accounting. The planning for health care systems in developing countries is extremely dependant on good, valid data. Whether you plan the catchment area for the future district hospitals, the number of health posts, the staff establishment for the central hospital or the drug budget in the Ministry. The "first digit law" can be used in medicine, public health, physiology and development aid to unmask questionable data, to discover unexpected challenges, difficulties in the data collection process, loss through corruption and criminal fraud. Our hypothesis suggests, that the "first digit law" is a cost effective tool, which is easy to use for most people in the medical profession, which does not really needs complicated statistical software and can be used on the spot, even in the resource restricted conditions of developing countries. Several preconditions (like the size of the data set and its reach over more than two dimensions) have to be fulfilled, but then Benfords law can be used by any clinician, physiologist, public health specialist or aid consultant without difficulties and without deeper statistical knowledge in the four steps, we suggest in this article. The consequences will be different depending on the level (local regional, national, continental, international) on which you will use the law. All levels will be enabled to get insight into the validity of the data-challenges for the other levels without the help of trained statisticians or accountants. We believe that the "first digit law" is a

International Perspectives on the First-Year Experience in Higher Education. The First-Year Experience Monograph Series No. 52

Science.gov (United States)

Nutt, Diane, Ed.; Calderon, Denis, Ed.

2009-01-01

Students around the globe have unique first-year experiences but struggle with many of the same challenges. This monograph focuses on their journeys and provides insights for educators interested in learning about how institutions across the globe provide supports to students dealing with first-year transition issues. Based on the successful…

The Advancement of World Digital Cities

DEFF Research Database (Denmark)

Yasuoka, Mika; Ishida, Toru; Aurigi, Alessandro

2009-01-01

This chapter reviews the advancement of several worldwide activities on regional information spaces empowered by advanced technologies such as sensors, information terminals, broadband networks and wireless networks. In the US and Canada, a large number of community networks supported by grass root...... activities appeared in the early 1990s. In Europe, more than one hundred digital cities have been tried, often supported by local government, central government and EU in the name of local digitalization. Asian countries have actively adopted the latest information technologies as a part of national...... initiatives. In the past 15 years since the first stage of digital cities, the development of the original digital cities has leveled off or stabilized. In spite of that, by looking back at the trajectory of digital cities, it is clear that digital environments in cities often benefit from the previous...

Effective conductivity, dielectric constant, and diffusion coefficient of digitized composite media via first-passage-time equations

International Nuclear Information System (INIS)

Torquato, S.; Kim, I.C.; Cule, D.

1999-01-01

We generalize the Brownian motion simulation method of Kim and Torquato [J. Appl. Phys. 68, 3892 (1990)] to compute the effective conductivity, dielectric constant and diffusion coefficient of digitized composite media. This is accomplished by first generalizing the first-passage-time equations to treat first-passage regions of arbitrary shape. We then develop the appropriate first-passage-time equations for digitized media: first-passage squares in two dimensions and first-passage cubes in three dimensions. A severe test case to prove the accuracy of the method is the two-phase periodic checkerboard in which conduction, for sufficiently large phase contrasts, is dominated by corners that join two conducting-phase pixels. Conventional numerical techniques (such as finite differences or elements) do not accurately capture the local fields here for reasonable grid resolution and hence lead to inaccurate estimates of the effective conductivity. By contrast, we show that our algorithm yields accurate estimates of the effective conductivity of the periodic checkerboard for widely different phase conductivities. Finally, we illustrate our method by computing the effective conductivity of the random checkerboard for a wide range of volume fractions and several phase contrast ratios. These results always lie within rigorous four-point bounds on the effective conductivity. copyright 1999 American Institute of Physics

Can We Teach Digital Natives Digital Literacy?

Science.gov (United States)

Ng, Wan

2012-01-01

In recent years, there has been much debate about the concept of digital natives, in particular the differences between the digital natives' knowledge and adoption of digital technologies in informal versus formal educational contexts. This paper investigates the knowledge about educational technologies of a group of undergraduate students…

Personal Digital Branding as a Professional Asset in the Digital Age

Science.gov (United States)

Kleppinger, Courtney A.

2015-01-01

In recent years, society’s rapid adoption of social media has made the boundary between professional and private life nearly indistinguishable. The literature provides guidance on how to demonstrate professionalism via social media platforms. Social media policies within health professions education tend to be legalistic in nature, serving primarily to highlight behaviors students should avoid. One missing element in social media literature is the concept of online invisibility. In this paper, we define personal digital branding, discuss the professional implications of choosing to abstain from social media use, and urge educators to recognize that the personal digital branding may be an emerging asset for young professionals in the twenty-first century. PMID:26430266

The first year: the support needs of parents caring for a child with an intellectual disability.

Science.gov (United States)

Douglas, Tracy; Redley, Bernice; Ottmann, Goetz

2016-11-01

To describe the support needs of parents caring for a child with an intellectual disability in the first year of life. Parents of children with intellectual disabilities face significant challenges during the first year of their child's life which is an important developmental period not previously addressed in the literature. The provision of support by health professionals, particularly nurses and midwives, during this crucial period can impact on parental well-being and on the health and developmental outcomes of their children. However, parents often feel unsupported. The study used a qualitative descriptive methodology. Semi-structured interviews were conducted with parents of eleven children with an intellectual disability in Victoria, Australia, during 2014. Interviews were digitally recorded, transcribed verbatim and analysed using thematic data analysis. Three key areas of support need were identified to assist parents to provide effective care for their child with an intellectual disability in the first year of life: (1) emotional support as parents adjusted to their role of caring for a child with an intellectual disability; (2) information support as they embarked on a quest for knowledge; and (3) support to facilitate their connection to peer networks. The findings highlighted inconsistent provision of support for parents. This study informs health professionals about how to provide holistic, timely support to parents of children with intellectual disabilities in the first year of life. There is an urgent need to review how nurses and midwives can provide relevant support that is responsive to parents' needs. © 2016 John Wiley & Sons Ltd.

Shaping the Curriculum: The Power of a Library's Digital Resources

Science.gov (United States)

Kirkwood, Patricia

2011-01-01

Researchers were the first adopters of digital resources available through the library. Online journals and databases make finding research articles much easier than when this author started as a librarian more than 20 years ago. Speedier interlibrary loan due to digital delivery means research materials are never far away. Making it easier for…

Digital Video: Get with It!

Science.gov (United States)

Van Horn, Royal

2001-01-01

Several years after the first audiovisual Macintosh computer appeared, most educators are still oblivious of this technology. Almost every other economic sector (including the porn industry) makes abundant use of digital and streaming video. Desktop movie production is so easy that primary grade students can do it. Tips are provided. (MLH)

THE SLOAN GREAT WALL. MORPHOLOGY AND GALAXY CONTENT

International Nuclear Information System (INIS)

Einasto, M.; Liivamaegi, L. J.; Tempel, E.; Saar, E.; Tago, E.; Einasto, P.; Enkvist, I.; Einasto, J.; MartInez, V. J.; Heinaemaeki, P.; Nurmi, P.

2011-01-01

We present the results of a study of the morphology and galaxy content of the Sloan Great Wall (SGW), the richest galaxy system in the nearby universe. We use the luminosity density field to determine superclusters in the SGW, and the fourth Minkowski functional V 3 and the morphological signature (the K 1 -K 2 shapefinder curve) to show the different morphologies of the SGW, from a single filament to a multibranching, clumpy planar system. We show that the richest supercluster in the SGW, SCl 126, and especially its core, resembles a very rich filament, while another rich supercluster in the SGW, SCl 111, resembles a 'multispider'-an assembly of high-density regions connected by chains of galaxies. We study the substructure of individual galaxy populations determined by their color in these superclusters using Minkowski functionals and find that in the high-density core of the SGW the clumpiness of red and blue galaxies is similar, but in the outskirts of superclusters the distribution of red galaxies is clumpier than that of blue galaxies. At intermediate densities, the systems of blue galaxies have tunnels through them. We assess the statistical significance of our results using the halo model and smoothed bootstrap. We study the galaxy content and the properties of groups of galaxies in the two richest superclusters of the SGW, paying special attention to bright red galaxies (BRGs) and the first ranked (the most luminous) galaxies in SGW groups. The BRGs are the nearby luminous red galaxies; they are mostly bright and red and typically reside in groups (several groups host five or more BRGs). About one-third of the BRGs are spirals. The scatter of colors of elliptical BRGs is smaller than that of spiral BRGs. About half of the BRGs and of first ranked galaxies in groups have large peculiar velocities. Groups with elliptical BRGs as their first ranked galaxies populate superclusters more uniformly than the groups that have a spiral BRG as their first ranked

The optical, infrared and radio properties of extragalactic sources observed by SDSS, 2mass and first surveys

International Nuclear Information System (INIS)

Z. Ivezic et al.

2002-01-01

We positionally match sources observed by the Sloan Digital Sky Survey (SDSS), the Two Micron All Sky Survey (2MASS), and the Faint Images of the Radio Sky at Twenty-cm (FIRST) survey. Practically all 2MASS sources are matched to an SDSS source within 2 arcsec; ∼ 11% of them are optically resolved galaxies and the rest are dominated by stars. About 1/3 of FIRST sources are matched to an SDSS source within 2 arcsec; ∼ 80% of these are galaxies and the rest are dominated by quasars. Based on these results, we project that by the completion of these surveys the matched samples will include about 10 7 and 10 6 galaxies observed by both SDSS and 2MASS, and about 250,000 galaxies and 50,000 quasars observed by both SDSS and FIRST. Here we present a preliminary analysis of the optical, infrared and radio properties for the extragalactic sources from the matched samples. In particular, we find that the fraction of quasars with stellar colors missed by the SDSS spectroscopic survey is probably not larger than ∼ 10%, and that the optical colors of radio-loud quasars are ∼ 0.05 mag. redder (with 4σ significance) than the colors of radio-quiet quasars

Using a first-year seminar to introduce nursing.

Science.gov (United States)

Mennenga, Heidi A; Tschetter, Lois

2013-01-01

First-year seminar courses designed to aid the transition of freshmen students to the collegiate experience are commonplace requirements at many 4-year institutions. The authors describe the development, implementation, and outcomes of a first-year seminar course with introductory nursing content.

Questions and Answers about School-Age Children in Self-Care: A Sloan Work and Family Research Network Fact Sheet

Science.gov (United States)

Sloan Work and Family Research Network, 2009

2009-01-01

The Sloan Work and Family Research Network has prepared Fact Sheets that provide statistical answers to some important questions about work-family and work-life issues. This Fact Sheet includes statistics about Children in Self-Care, and answers the following questions about school-age children in self-care: (1) How many school-age children are in…

The CSIR - the first 40 years

CSIR Research Space (South Africa)

Kingwill, DG

1990-01-01

Full Text Available This story of the first 40 years of the Council for Scientific and Industrial Research (CSIR) is presented in three parts. The first includes the events leading up to its establishment in 1945 and discusses the need for such a body in South Africa...

SPEAR 3: the First Year of Operation

International Nuclear Information System (INIS)

Hettel, R.O.

2006-01-01

The first electrons were accumulated in the newly completed 3-GeV SPEAR 3 storage ring on December 15, 2003, five days after the beginning of commissioning. By mid-January of 2004, 100 mA were stored, the maximum current allowed in the first phase of SPEAR 3 operation, and ring characterization and tuning continued until early March when the first photon beam line was opened for users. After the first year of operation the SPEAR 3 beam properties and ring performance had been extensively measured. These include micron stability using slow orbit feedback, an emittance coupling of ∼0.1% and 50-h lifetimes. The performance of SPEAR 3 during its first year of commissioning and operation and the improvement plans are described

Basic entwinements: unassuming analogue inserts in basic digital modeling (courses)

DEFF Research Database (Denmark)

Wiesner, Thomas

2012-01-01

Ubiquitous, basic digital modelling tools are currently deployed with relative ease in architecture schools during the course of first year studies. While these first architectural projects essays sometimes communicate matter with already quite impressive professional outlooks, a certain disparit...

Digital Archive of UkrVO: first results of MAO NASU Solar System Bodies photographic plate processing

Science.gov (United States)

Ivanov, G.; Pakuliak, L.; Shatokhina, S.; Yizhakevych, E.; Kazantseva, L.; Andruk, V.

The digitizing and processing of photographic plates with the images of the outer planets and their satellites from the archive collections of MAO NASU and AO of Kiev university included into the UkrVO Joint Digital Archive (JDA) have been made. Plates were obtained in the last half of the 20th century. The digitizing of JDA archive plates and inclusion of plate preview images into GPA database has been under way, using two models of flatbed scanners: Microtek ScanMaker 9800XL TMA and Epson Expression 10000XL. The database with metadata of plates is allocated on the computational resources of MAO NASU (http://gua.db.ukr-vo.org). Plates have been scanned at 16-bits grey dynamic range, with a resolution of 1200-1600 dpi, and saved in TIFF format. Linear dimensions of images are up to 13 thousand pixels (for plates 30.30 cm). The astrometric and photometric calibration procedures have been done in the LINUX-MIDASROMAFOT environment and Tycho-2 as reference with the image processing procedure specially developed for digitized images of huge linear dimensions on the basis of the image inherent traits. First results of digitized plate processing give the rms errors of 10 and 20 mas for RA, DEC respectively. (O-C) for plates with Pluto in comparison to JPL PLU021.DE405 has been derived of 140(RA) and 270(DEC) mas.

Digital Level Layers for Digital Curve Decomposition and Vectorization

Directory of Open Access Journals (Sweden)

Laurent Provot

2014-07-01

Full Text Available The purpose of this paper is to present Digital Level Layers and show the motivations for working with such analytical primitives in the framework of Digital Geometry. We first compare their properties to morphological and topological counterparts, and then we explain how to recognize them and use them to decompose or vectorize digital curves and contours.

Designing for Diverse Classrooms: Using iPpads and Digital Cameras to Compose eBooks with Emergent Bilingual/Biliterate Four-Year-Olds

Science.gov (United States)

Rowe, Deborah Wells; Miller, Mary E.

2016-01-01

This paper reports the findings of a two-year design study exploring instructional conditions supporting emerging, bilingual/biliterate, four-year-olds' digital composing. With adult support, children used child-friendly, digital cameras and iPads equipped with writing, drawing and bookmaking apps to compose multimodal, multilingual eBooks…

The First 50 Years of Electronic Watermarking

Directory of Open Access Journals (Sweden)

Ingemar J. Cox

2002-02-01

Full Text Available Electronic watermarking can be traced back as far as 1954. The last 10 years has seen considerable interest in digital watermarking, due, in large part, to concerns about illegal piracy of copyrighted content. In this paper, we consider the following questions: is the interest warranted? What are the commercial applications of the technology? What scientific progress has been made in the last 10 years? What are the most exciting areas for research? And where might the next 10 years take us? In our opinion, the interest in watermarking is appropriate. However, we expect that copyright applications will be overshadowed by applications such as broadcast monitoring, authentication, and tracking content distributed within corporations. We further see a variety of applications emerging that add value to media, such as annotation and linking content to the Web. These latter applications may turn out to be the most compelling. Considerable progress has been made toward enabling these applications—perceptual modelling, security threats and countermeasures, and the development of a bag of tricks for efficient implementations. Further progress is needed in methods for handling geometric and temporal distortions. We expect other exciting developments to arise from research in informed watermarking.

Relations estimate between investment in digital media and financial variables of companies: a Colombian overview

Directory of Open Access Journals (Sweden)

Amalia Novoa Hoyos

2016-06-01

Full Text Available This article shows a first estimate about the relationship between investment in digital media and some financial variables in Colombia. First, a literature review is made about the impact of marketing and digital marketing in Company performance. Then, an analysis of the sectorial variables such as liquidity, profitability, indebtedness and concentration in sectors like food, personal grooming, automotive, drinking and tobacco, construction, entertainment, furniture, services, telecommunication, tourism and clothing using the technique of ordinary squared minimums (OSM in the years 2011, 2012, 2013 and 2014. For this study, investment in digital media in the above- mentioned years is also taken into account.

First Year Distance Transition Pedagogy: Synchronous online classrooms

Directory of Open Access Journals (Sweden)

Wendy Fasso

2013-04-01

Full Text Available The design and facilitation of distance online courses for first year students must consider both first year, and distance pedagogy. One technology with the promise to meet the needs of first year distance students is the synchronous online classroom. Teacher practice as they transition from face to face to distance environments is influenced by their private theories about technology and pedagogy. Any limitations posed by these private theories may limit in turn the technological, pedagogical and content knowledge of the teachers – TPACK. This paper reports on the case of a regional university as it transitions to online, distance learning in the first year context, with a particular focus on pedagogy in the online classroom. It contributes to the first year pedagogy literature by considering the influences of existing practice of university teachers in the transition to distance learning with a particular focus on synchronous web-based tutorials. It provides recommendations to other institutions in terms of transition strategies, the pedagogical and learning benefits that are enabled and professional development needs of teachers. Normal 0 false false false EN-AU ZH-CN X-NONE

[The role of a single PCA3 test before a first negative prostate biopsy: 5-year follow-up].

Science.gov (United States)

Bernardeau, S; Charles, T; Fromont-Hankard, G; Irani, J

2017-04-01

We report a 5-year follow-up of a cohort of patients who underwent a first prostate biopsy following a prostate cancer antigen 3 (PCA3) test. We reviewed consecutive patients who had in 2008 a single urinary PCA3 test using the Gen-Probe ® assay before a first prostate biopsy for a prostate-specific antigen (PSA) between 3 and 20ng/mL and/or a suspicious digital rectal examination. PCA3 performances were analyzed in 2008 and then in 2013 after taking into account the results of repeat biopsies. At initial biopsy in 2008, among the 125 patients study cohort, prostate cancer was diagnosed in 47 patients (37.6%). Abnormal digital rectal exam, PSA density, prostate volume and PCA3 score were significantly associated with prostate cancer diagnosis. PCA3 area under the curve of the receiver operating curve was 0.67 [95%CI: 0.57-0.76] with an optimal threshold of PCA3 in this sample of 24 units. During the 5-year follow-up, among the 78 patients with a negative prostate biopsy in 2008, 23 (29.5%) had a repeat prostate biopsy of whom 14 were diagnosed with prostate cancer. PCA3 score measured in 2008 was associated with prostate cancer diagnosis (P=0.002). All 9 patients with a negative repeat prostate biopsy had a PCA3 score below the cut-off while this was the case in only 2 patients among the 14 with a positive repeat prostate biopsy. The results of a single PCA3 test before a first prostate biopsy seems to be a useful aid in deciding whether to perform a repeat biopsy. 4. Copyright © 2017. Published by Elsevier Masson SAS.

Sports Digitalization

DEFF Research Database (Denmark)

Xiao, Xiao; Hedman, Jonas; Tan, Felix Ter Chian

2017-01-01

evolution, as digital technologies are increasingly entrenched in a wide range of sporting activities and for applications beyond mere performance enhancement. Despite such trends, research on sports digitalization in the IS discipline is surprisingly still nascent. This paper aims at establishing...... a discourse on sports digitalization within the discipline. Toward this, we first provide an understanding of the institutional characteristics of the sports industry, establishing its theoretical importance and relevance in our discipline; second, we reveal the latest trends of digitalization in the sports...

Digital radiography detectors - A technical overview: Part 1

International Nuclear Information System (INIS)

Lanca, Luis; Silva, Augusto

2009-01-01

During the last two decades screen-film (SF) systems have been replaced by digital X-ray systems. The advent of digital technologies brought a number of digital solutions based on different detector and readout technologies. Improvements in technology allowed the development of new digital technologies for projection radiography such as computed radiography (CR) and digital radiography (DR). The large number of scientific papers concerning digital X-ray systems that have been published over the last 25 years indicates the relevance of these technologies in healthcare. There are important differences among different detector technologies that may affect system performance and image quality for diagnostic purposes. Radiographers are expected to have an effective understanding of digital X-ray technologies and a high level of knowledge and awareness concerning the capabilities of these systems. Patient safety and reliable diagnostic information are intrinsically linked to these factors. In this review article - which is the first of two parts - a global overview of the digital radiography systems (both CR and DR) currently available for clinical practice is provided

Controls on Arctic sea ice from first-year and multi-year survival rates

Energy Technology Data Exchange (ETDEWEB)

Hunke, Jes [Los Alamos National Laboratory

2009-01-01

The recent decrease in Arctic sea ice cover has transpired with a significant loss of multi year ice. The transition to an Arctic that is populated by thinner first year sea ice has important implications for future trends in area and volume. Here we develop a reduced model for Arctic sea ice with which we investigate how the survivability of first year and multi year ice control the mean state, variability, and trends in ice area and volume.

Digital Ethics Past, Present, Futures (Foreword)

DEFF Research Database (Denmark)

Ess, Charles

2012-01-01

I offer an overview of Digital Ethics (DE) as a field of enquiry that serves as the larger context for this volume and its constituent chapters. Along the way, I point out the trajectories and contributions of this volume and its constituent chapters to DE. To do so, I first take up four difficul......I offer an overview of Digital Ethics (DE) as a field of enquiry that serves as the larger context for this volume and its constituent chapters. Along the way, I point out the trajectories and contributions of this volume and its constituent chapters to DE. To do so, I first take up four...... difficulties facing efforts to develop a working definition of “digital ethics.” I then offer a taxonomy of the ethical issues that constitute much of the main foci of DE over the past five years, and indicate where these issues are further addressed in this volume. I conclude with some suggestions of emerging...... ethical domains and challenges that will likely become increasingly important components of DE, including one represented in this volume....

Research on Digital Product Modeling Key Technologies of Digital Manufacturing

Institute of Scientific and Technical Information of China (English)

DING Guoping; ZHOU Zude; HU Yefa; ZHAO Liang

2006-01-01

With the globalization and diversification of the market and the rapid development of Information Technology (IT) and Artificial Intelligence (AI), the digital revolution of manufacturing is coming. One of the key technologies in digital manufacturing is product digital modeling. This paper firstly analyzes the information and features of the product digital model during each stage in the product whole lifecycle, then researches on the three critical technologies of digital modeling in digital manufacturing-product modeling, standard for the exchange of product model data and digital product data management. And the potential signification of the product digital model during the process of digital manufacturing is concluded-product digital model integrates primary features of each stage during the product whole lifecycle based on graphic features, applies STEP as data exchange mechanism, and establishes PDM system to manage the large amount, complicated and dynamic product data to implement the product digital model data exchange, sharing and integration.

The Test of Logical Thinking as a predictor of first-year pharmacy students' performance in required first-year courses.

Science.gov (United States)

Etzler, Frank M; Madden, Michael

2014-08-15

To investigate the correlation of scores on the Test of Logical Thinking (TOLT) with first-year pharmacy students' performance in selected courses. The TOLT was administered to 130 first-year pharmacy students. The examination was administered during the first quarter in a single session. The TOLT scores correlated with grades earned in Pharmaceutical Calculations, Physical Pharmacy, and Basic Pharmacokinetics courses. Performance on the TOLT has been correlated to performance in courses that required the ability to use quantitative reasoning to complete required tasks. In the future, it may be possible to recommend remediation, retention, and/or admission based in part on the results from the TOLT.

SLEEP HABITS AMONG FIRST YEAR MEDICAL STUDENTS

OpenAIRE

Neera; Varun; Yogesh

2016-01-01

Sleep is part of the rhythm of life; without a good sleep the mind is less adaptive, mood is altered and the body loses the ability to refresh. The sleep-wake cycle of medical students is quite different and sleep deprivation, poor sleep quality, occurrence of napping episodes during the day. This study was designed to assess sleep habits in first year medical students. MATERIAL AND METHODS Participants of this study were healthy medical students of first year MBBS course of S...

Why Do First-Year Students of German Lose Motivation during their First Year at University?

Science.gov (United States)

Busse, Vera

2013-01-01

This article explores motivational changes of first-year students enrolled on German degree courses at two major UK universities. It reports on the qualitative data obtained by a longitudinal mixed-methods study, and focuses on the interplay between students' motivation and the higher education learning environment. In particular, the article aims…

A pediatric digital storytelling system for third year medical students: The Virtual Pediatric Patients

Science.gov (United States)

D'Alessandro, Donna M; Lewis, Tamra E; D'Alessandro, Michael P

2004-01-01

Background Computer-based patient simulations (CBPS) are common, effective, instructional methods for medical students, but have limitations. The goal of this project was to describe the development of a CBPS designed to overcome some of these limitations and to perform an online evaluation. Methods In 1996, patients and families experiencing a common pediatric problem were interviewed, photographed and a chart review completed. A digital storytelling template was developed: 1. patient's story, evaluation and clinical course, 2. problem-based approach to the evaluation, and 3. discussion of disease process. The media was digitized and placed onto the Internet. The digital stories and a 10-question online survey were pilot tested. Online survey responses were collected from 1999–2003. Overall use of the digital stories was measured by computer server logs and by the number of hyperlinks to the CBPS. Results Eight stories were created using this system. Over 4.5 years, 814,148 digital story pages were read by 362,351 users. Hyperlink citations from other websites to the CBPS were 108. Online survey respondents (N = 393) described the overall quality as excellent or very good (88.4%). The stores were clearly written (92%) at an appropriate level (91.4%). Respondents felt they could begin to evaluate a similar case presentation (95.4%), and would remember the case in the future (91%). Conclusions A new type of CBPS, the digital storytelling system, has been developed and evaluated which and appears to be successful in overcoming some of the limitations of earlier CBPS by featuring patient's stories in their own words, by focusing on problems rather than diseases, and by having stories that are quick for students to work through. PMID:15260883

APASS Landolt-Sloan BVgri photometry of Rave stars. I. Data, effective temperatures, and reddenings

Energy Technology Data Exchange (ETDEWEB)

Munari, U.; Siviero, A. [INAF Osservatorio Astronomico di Padova, I-36012 Asiago (VI) (Italy); Henden, A. [AAVSO, Cambridge, MA (United States); Frigo, A. [ANS Collaboration, c/o Astronomical Observatory, Padova (Italy); Zwitter, T. [Faculty of Mathematics and Physics, University of Ljubljana, 1000 Ljubljana (Slovenia); Bienaymé, O.; Siebert, A. [Observatoire Astronomique, Université de Strasbourg, CNRS, 11 rue de l' université F-67000 Strasbourg (France); Bland-Hawthorn, J. [Sydney Institute for Astronomy, University of Sydney, NSW 2006 (Australia); Boeche, C.; Grebel, E. K. [Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstr. 12-14, D-69120 Heidelberg (Germany); Freeman, K. C. [Mount Stromlo Observatory, RSAA, Australian National University, Weston Creek, Canberra, ACT 2611 (Australia); Gibson, B. K. [Jeremiah Horrocks Institute, University of Central Lancashire, Preston, PR1 2HE (United Kingdom); Gilmore, G.; Kordopatis, G. [Institute of Astronomy, Cambridge University, Madingley Road, Cambridge CB3 0HA (United Kingdom); Helmi, A. [Kapteyn Astronomical Institute, University of Groningen, PO Box 800, 9700 AV Groningen (Netherlands); Levine, S. E. [Lowell Observatory, Flagstaff, AZ (United States); Navarro, J. F. [Department of Physics and Astronomy, University of Victoria, Victoria, BC V8P 5C2 (Canada); Parker, Q. A.; Reid, W. [Department of Physics and Astronomy, Macquarie University, NSW 2109 (Australia); Seabroke, G. M. [Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, RH5 6NT (United Kingdom); and others

2014-11-01

We provide AAVSO Photometric All-Sky Survey (APASS) photometry in the Landolt BV and Sloan g'r'i' bands for all 425,743 stars included in the fourth RAVE Data Release. The internal accuracy of the APASS photometry of RAVE stars, expressed as the error of the mean of data obtained and separately calibrated over a median of four distinct observing epochs and distributed between 2009 and 2013, is 0.013, 0.012, 0.012, 0.014, and 0.021 mag for the B, V, g', r', and i' bands, respectively. The equally high external accuracy of APASS photometry has been verified on secondary Landolt and Sloan photometric standard stars not involved in the APASS calibration process and on a large body of literature data on field and cluster stars, confirming the absence of offsets and trends. Compared with the Carlsberg Meridian Catalog (CMC-15), APASS astrometry of RAVE stars is accurate to a median value of 0.098 arcsec. Brightness distribution functions for the RAVE stars have been derived in all bands. APASS photometry of RAVE stars, augmented by 2MASS JHK infrared data, has been χ{sup 2} fitted to a densely populated synthetic photometric library designed to widely explore temperature, surface gravity, metallicity, and reddening. Resulting T {sub eff} and E {sub B–V}, computed over a range of options, are provided and discussed, and will be kept updated in response to future APASS and RAVE data releases. In the process, we find that the reddening caused by a homogeneous slab of dust, extending for 140 pc on either side of the Galactic plane and responsible for E{sub B−V}{sup poles} = 0.036 ± 0.002 at the Galactic poles, is a suitable approximation of the actual reddening encountered at Galactic latitudes |b| ≥ 25°.

APASS Landolt-Sloan BVgri Photometry of RAVE Stars. I. Data, Effective Temperatures, and Reddenings

Science.gov (United States)

Munari, U.; Henden, A.; Frigo, A.; Zwitter, T.; Bienaymé, O.; Bland-Hawthorn, J.; Boeche, C.; Freeman, K. C.; Gibson, B. K.; Gilmore, G.; Grebel, E. K.; Helmi, A.; Kordopatis, G.; Levine, S. E.; Navarro, J. F.; Parker, Q. A.; Reid, W.; Seabroke, G. M.; Siebert, A.; Siviero, A.; Smith, T. C.; Steinmetz, M.; Templeton, M.; Terrell, D.; Welch, D. L.; Williams, M.; Wyse, R. F. G.

2014-11-01

We provide AAVSO Photometric All-Sky Survey (APASS) photometry in the Landolt BV and Sloan g'r'i' bands for all 425,743 stars included in the fourth RAVE Data Release. The internal accuracy of the APASS photometry of RAVE stars, expressed as the error of the mean of data obtained and separately calibrated over a median of four distinct observing epochs and distributed between 2009 and 2013, is 0.013, 0.012, 0.012, 0.014, and 0.021 mag for the B, V, g', r', and i' bands, respectively. The equally high external accuracy of APASS photometry has been verified on secondary Landolt and Sloan photometric standard stars not involved in the APASS calibration process and on a large body of literature data on field and cluster stars, confirming the absence of offsets and trends. Compared with the Carlsberg Meridian Catalog (CMC-15), APASS astrometry of RAVE stars is accurate to a median value of 0.098 arcsec. Brightness distribution functions for the RAVE stars have been derived in all bands. APASS photometry of RAVE stars, augmented by 2MASS JHK infrared data, has been χ2 fitted to a densely populated synthetic photometric library designed to widely explore temperature, surface gravity, metallicity, and reddening. Resulting T eff and E B - V , computed over a range of options, are provided and discussed, and will be kept updated in response to future APASS and RAVE data releases. In the process, we find that the reddening caused by a homogeneous slab of dust, extending for 140 pc on either side of the Galactic plane and responsible for EpolesB-V = 0.036 ± 0.002 at the Galactic poles, is a suitable approximation of the actual reddening encountered at Galactic latitudes |b| >= 25°.

First-year seminar intervention: Enhancing firstyear mathematics ...

African Journals Online (AJOL)

First-year seminar intervention: Enhancing firstyear mathematics performance at ... South Africa has opened up access to higher education over the past 20 years. ... The research question that this paper addresses is: What is the relationship ...

First aid and basic life support training for first year medical students.

Science.gov (United States)

Altintaş, Kerim Hakan; Yildiz, Ali Naci; Aslan, Dilek; Ozvariş, Sevkat Bahar; Bilir, Nazmi

2009-12-01

We developed 24 and 12-h programs for first aid and basic life support (FA-BLS) training for first-year medical students and evaluated the opinions of both the trainers and trainees on the effectiveness of the programs. The trainees were the first-year students of academic years 2000-2001 (316 students) and 2001-2002 (366 students). The evaluations of the participants were collected from short questionnaires created specifically for the study. For the 24-h training program, most of the students stated that FA-BLS sessions met their expectations (85.9%) and they were satisfied with the training (91.1%). Of the participants, 75.6% stated that they could apply FA confidently in real situations simulating the topics they learned in the FA-BLS sessions. For the 12-h training program, 84.4% of the students felt themselves competent in FA-BLS applications. The trainers considered both of the programs as effective.

Leech Therapy For The Treatment Of Venous Congestion In Flaps, Digital Re-Plants And Revascularizations - A Two-Year Review From A Regional Centre.

Science.gov (United States)

Butt, Ahsan Masood; Ismail, Amir; Lawson-Smith, Matthew; Shahid, Muhammad; Webb, Jill; Chester, Darren L

2016-01-01

Leeches are a well-recognized treatment for congested tissue. This study reviewed the efficacy of leech therapy for salvage of venous congested flaps and congested replanted or revascularized hand digits over a 2-year period. All patients treated with leeches between 1 Oct 2010 and 30 Sep 2012 (two years) at Queen Elizabeth Hospital, Birmingham, UK were included in the study. Details regarding mode of injury requiring reconstruction, surgical procedure, leech therapy duration, subsequent surgery requirement and tissue salvage rates were recorded. Twenty tissues in 18 patients required leeches for tissue congestion over 2 years: 13 men and 5 women. The mean patient age was 41 years (range 17-79). The defect requiring reconstruction was trauma in 16 cases, following tumour resection in two, and two miscellaneous causes. Thirteen cases had flap reconstruction and seven digits in six patients had hand digit replantations or revascularisation. Thirteen of 20 cases (65%) had successful tissue salvage following leech therapy for congestion (77% in 10 out of 13 flaps, and 43% in 3 of 7 digits). The rate of tissue salvage in pedicled flaps was good 6/6 (100%) and so was in digital revascularizations 2/3 (67%), but poor in digital re-plants 1/4 (25%) and free flaps 0/2 (0%). Leeches are a helpful tool for congested tissue salvage and in this study, showed a greater survival benefit for pedicled flaps than for free flaps or digital replantations.

A first experience with digital complete overdentures

OpenAIRE

Bajunaid, Salwa Omar

2016-01-01

The development of computer-aided design/computer-aided manufacturing systems for dentistry in the 1980s resulted in the successful fabrication of crowns, fixed dental prostheses, and superstructures for both natural teeth and dental implants. Today, this technology is available for constructing digitally designed and milled, completely removable dental prostheses. The procedure uses clinical and laboratory protocols that allow fabrication of completely removable prostheses within two clinica...

Introduction of the digitization software GDgraph

International Nuclear Information System (INIS)

Chen Guochang; Jin Yongli; Wang Jimin

2015-01-01

The evaluators and experimenters always desire to have full and latest experimental data sets. However, the data are often published as figures without any numerical values for some publications or journals. Furthermore, the quality of figures is not always good enough, especially for some figures scanned from the hard copy of old publications. On the other hand, the researchers would like to retrieve the data directly from EXFOR database. Digitization of figures is only one method to obtain the numerical data and correlative uncertainty, when there are only figures available from publications. Therefore we need a digitization tool to fit the requirements from evaluation, measurement and EXFOR compilation in CNDC. Before 2000, there have no common software to digitize experimental and evaluated data. And the quality of digitization results can not fit the requirements of evaluation and measurement using the traditional coordinate paper or rule. The end of twenty century, the PC was developed so quickly that to develop a software for digitization purpose become possible. Since 1997, CNDC devotes to design and develop a software for digitization. Four years later, the first version of digitization software GDGraph was developed using VC++ and released in CNDC. Although, the functions of the 1 st version of GDGraph is fit the basic requirements of digitization only, in which can digitize one group data excluding data error, BMP image format only, and it can not randomly delete digitizing data points. However, it obtains higher quality digitizing results and efficiency than the traditional method

A map of the universe

Energy Technology Data Exchange (ETDEWEB)

Gott III, J. Richard; Juric, Mario; Schlegel, David; Hoyle, Fiona; Vogeley, Michael; Tegmark, Max; Bahcall, Neta; Brinkmann, Jon

2003-10-20

We have produced a new conformal map of the universe illustrating recent discoveries, ranging from Kuiper belt objects in the Solar system, to the galaxies and quasars from the Sloan Digital Sky Survey. This map projection, based on the logarithm map of the complex plane, preserves shapes locally, and yet is able to display the entire range of astronomical scales from the Earth s neighborhood to the cosmic microwave background. The conformal nature of the projection, preserving shapes locally, may be of particular use for analyzing large scale structure. Prominent in the map is a Sloan Great Wall of galaxies 1.37 billion light years long, 80 percent longer than the Great Wall discovered by Geller and Huchra and therefore the largest observed structure in the universe.

Digital Economy for Sustainable Economic Growth

Directory of Open Access Journals (Sweden)

Shuyong Guo

2017-12-01

Full Text Available Recent decades have seen a rapid digital transformation resulting in important and sometimes even crucial changes in business, society and the global economy. After the global crisis of 2008–2009, digital industries have been among the most dynamic and promising in the global economy. Nevertheless, the world lacks equilibrium between benefits and risks in the digital economy, which explains the need for global governance in this sphere. This article analyzes the role and characteristics of the G20 in the introduction of global governance in the digital economy. The authors review what’s meant by the digital economy and define the key characteristics of this sector, as well as highlight the challenges to international cooperation, analyze the digital strategies of G20 countries, study the G20’s participation in the global governance of the digital economy, analyze the potential for the leaders of China and Russia, and make recommendations concerning the participation of the G20 in the global governance of the digital economy. The authors arrive at the following conclusions. First, society has to govern the digital economy properly in order to eliminate disparities between developed and developing countries, as well as address cyber security and other threats, and promote a higher quality of life for all. Second, the G20 has very limited experience in the governing of the digital economy, but as a leader in terms of soft power, and as an organization with limited membership that includes both countries with a developed digital sector and countries that lag behind, it may play a great role in the digital economy’s global governance. Third, the US has historically been a leader in the IT sector and the digital economy. In recent years, China has sufficiently improved its positions, which allows it to aspire to a higher role in global governance. Russia may also play a greater (though not a leading role, taking into account its experience and

The digital Emily project: achieving a photorealistic digital actor.

Science.gov (United States)

Alexander, Oleg; Rogers, Mike; Lambeth, William; Chiang, Jen-Yuan; Ma, Wan-Chun; Wang, Chuan-Chang; Debevec, Paul

2010-01-01

The Digital Emily Project uses advanced face scanning, character rigging, performance capture, and compositing to achieve one of the world's first photorealistic digital facial performances. The project scanned the geometry and reflectance of actress Emily O'Brien's face in 33 poses, showing different emotions, gaze directions, and lip formations in a light stage. These high-resolution scans-accurate to skin pores and fine wrinkles-became the basis for building a blendshape-based facial-animation rig whose expressions closely matched the scans. The blendshape rig drove displacement maps to add dynamic surface detail. A video-based facial animation system animated the face according to the performance in a reference video, and the digital face was tracked onto the video's motion and rendered under the same illumination. The result was a realistic 3D digital facial performance credited as one of the first to cross the "uncanny valley" between animated and fully human performances.

Knowledge Resources - A Knowledge Management Approach for Digital Ecosystems

Science.gov (United States)

Kurz, Thomas; Eder, Raimund; Heistracher, Thomas

The paper at hand presents an innovative approach for the conception and implementation of knowledge management in Digital Ecosystems. Based on a reflection of Digital Ecosystem research of the past years, an architecture is outlined which utilizes Knowledge Resources as the central and simplest entities of knowledge transfer. After the discussion of the related conception, the result of a first prototypical implementation is described that helps the transformation of implicit knowledge to explicit knowledge for wide use.

Sports Digitalization : An Overview and A Research Agenda

NARCIS (Netherlands)

Xiao, Xiao; Chian Tan, Felix Ter; Lim, Eric T.K.; Henningsson, Stefan; Vatrapu, Ravi; Hedman, Jonas; Tan, Chee Wee; Clemenson, Torkil; Mukkamala, Raghava Rao; Van Hillegersberg, Jos

2018-01-01

Ever since its first manifesto in Greece around 3000 years ago, sports as a field has accumulated a long history with strong traditions while at the same time, gone through tremendous changes toward professionalization and commercialization. The current waves of digitalization have intensified its

Digital image intensifier radiography. One year's experience with a Polytron system

International Nuclear Information System (INIS)

Busch, H.P.; Lehmann, K.J.; Georgi, M.

1989-01-01

Since January 1988, digital image intensifier radiography has been used in the Clinic in Mannheim for DSA examinations and also in place of conventional screen/film examinations. Measurements have shown that compared with 100 mm and film/screen formats, digital radiography has poorer spatial resolution, but improved contrast resolution. The most common use of digital radiography was for examinations of the gastrointestinal tract. Using the demonstration of the mucosal fine relief pattern as a criterion of image quality, digital image intensifier radiography was able to achieve this satisfactorily. Comparison with film/screen examinations showed no loss of diagnostic information. Advantages of image intensifier radiography are reduced radiation dose, the possibility of postprocessing and economy. On the basis of 399 examinations, digital image intensifier radiography is now firmly established as part of the daily routine of the Mannheim Clinic. (orig.) [de

Digital earth applications in the twenty-first century

NARCIS (Netherlands)

de By, R.A.; Georgiadou, P.Y.

2014-01-01

In these early years of the twenty-first century, we must look at how the truly cross-cutting information technology supports other innovations, and how it will fundamentally change the information positions of government, private sector and the scientific domain as well as the citizen. In those

First-Year and Non-First-Year Student Expectations Regarding In-Class and Out-of-Class Learning Activities in Introductory Biology †

Science.gov (United States)

Brown, Tanya L.; Brazeal, Kathleen R.; Couch, Brian A.

2017-01-01

National calls for teaching transformation build on a constructivist learning theory and propose that students learn by actively engaging in course activities and interacting with other students. While interactive pedagogies can improve learning, they also have the potential to challenge traditional norms regarding class participation and learning strategies. To better understand the potential openness of students to interactive teaching practices, we administered a survey during the first week of two sections of an introductory biology course to characterize how students envisioned spending time during class as well as what activities they expected to complete outside of class during non-exam weeks and in preparation for exams. Additionally, we sought to test the hypothesis that the expectations of first-year students differed from those of non-first-year students. Analyses of closed-ended and open-ended questions revealed that students held a wide range of expectations and that most students expressed expectations consistent with some degree of transformed teaching. Furthermore, first-year students expected more active learning in class, more out-of-class coursework during non-exam weeks, and more social learning strategies than non-first-year students. We discuss how instructor awareness of incoming student expectations might be used to promote success in introductory science courses. PMID:28512514

Examining the Extent and Nature of Online Learning in American K-12 Education: The Research Initiatives of the Alfred P. Sloan Foundation

Science.gov (United States)

Picciano, Anthony G.; Seaman, Jeff; Shea, Peter; Swan, Karen

2012-01-01

In 1992, the Alfred P. Sloan Foundation began its "Anytime, Anyplace Learning Program", the purpose of which was to explore educational alternatives for people who wanted to pursue an education via Internet technology. Part of this grant activity was a research award to the Babson College Survey Research Group to examine online learning in…

Ten year neurocognitive trajectories in first-episode psychosis

DEFF Research Database (Denmark)

Simonsen, Erik; Barder, Helene E.; Sundet, Kjetil

2013-01-01

Objective: Neurocognitive impairment is commonly reported at onset of psychotic disorders. However, the long-term neurocognitive course remains largely uninvestigated in first episode psychosis (FEP) and the relationship to clinically significant subgroups even more so. We report 10 year...... years) were followed-up neurocognitively over five assessments spanning 10 years. The test battery was divided into four neurocognitive indices; Executive Function, Verbal Learning, Motor Speed, and Verbal Fluency. The sample was grouped into those relapsing or not within the first, second and fifth...... year. Results: The four neurocognitive indices showed overall stability over the 10 year period. Significant relapse by index interactions were found for all indices except Executive Function. Follow-up analyses identified a larger significant decrease over time for the encoding measure within Verbal...

Interesting features in the combined Galex and Sloan color diagrams of solar-like galactic populations

Energy Technology Data Exchange (ETDEWEB)

Smith, Myron A.; Shiao, Bernard [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Bianchi, Luciana, E-mail: myronmeister@gmail.com, E-mail: shiao@stsci.edu, E-mail: bianchi@pha.jhu.edu [Johns Hopkins University, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

2014-06-01

We report on intriguing photometric properties of Galactic stars observed in the Galaxy Evolution Explorer (GALEX) satellite's far-UV (FUV) and near-UV (NUV) bandpasses, as well as from the ground-based Sloan Digital Sky Survey (SDSS) and the Kepler Input Catalog. The first property is that the (FUV – NUV) color distribution of stars in the Kepler field consists of two well-separated peaks. A second and more perplexing property is that for stars with spectral types G or later the mean (FUV – NUV) color becomes much bluer, contrary to expectation. Investigating this tendency further, we found in two samples of mid-F through K type stars that 17%-22% of them exhibit FUV excesses relative to their NUV fluxes and spectral types. A correction for FUV incompleteness of the FUV magnitude-limited star sample brings this ratio to 14%-18%. Nearly the same fractions are also discovered among members of the Kepler Eclipsing Binary Catalog and in the published list of Kepler Objects of Interest. These UV-excess ('UVe') colors are confirmed by the negative UV continuum slopes in GALEX spectra of members of the population. The SDSS spectra of some UVe stars exhibit metallic line weakening, especially in the blue. This suggests an enhanced contribution of UV flux relative to photospheric flux of a solar-type single star. We consider the possibility that the UV excesses originate from various types of hot stars, including white dwarf DA and sdB stars, binaries, and strong chromosphere stars that are young or in active binaries. The space density of compact stars is too low to explain the observed frequency of the UVe stars. Our model atmosphere-derived simulations of colors for binaries with main-sequence pairs with a hot secondary demonstrate that the color loci conflict with the observed sequence. As a preferred alternative we are left with the active chromospheres explanation, whether in active close binaries or young single stars, despite the expected paucity

Digital radiography is promising in industrial testing

International Nuclear Information System (INIS)

Del Fabbro, F.

2015-01-01

Digital radiography has recently entered the industrial world as a tool for non-destructive testing. There are 3 types of digital radiography: computed radiography (CR), direct radiography (DR) and computed tomography (CT). In computed radiography, traditional silver-halide films are replaced by photostimulable phosphor imaging plates that are activated through laser scanning and digitized. Direct radiography uses a flat panel detector (FPD) composed of X-ray detectors that performs an immediate digital conversion of the image that can be read by a computer. DR is a perfect tool for industrial testing but the fragility of the FPD panels reduces its uses. Computed tomography is based on the principle of DR to get data corresponding to successive cross-section images of the object. These data are processed by a software to get a 3-dimensional image of the object. CT was first developed for medical use but requires some improvement to become more accurate, faster, particularly for big objects. In recent years DR has enjoyed the highest growth rate in digital radiography. (A.C.)

Digital signal processing at GEND's data center

International Nuclear Information System (INIS)

Jackson, J.E.

1977-01-01

The conversion and recording of analog signals in digital form has been an active element in the manufacturing operations of the General Electric Neutron Devices Department (GEND) since 1966. The first computerized data system for these digitized waveforms was implemented at GEND's data center approximately two years later during 1968. The evolution and integration of these two activities at GEND are addressed in this paper. Beginning with the tester--data center interface, emphasis is placed on previous approaches, current capabilities, near-term trends, and future requirements. The digitizing process has developed into a firmly established set of hardware and associated software techniques which has proven itself as an accurate, reliable procedure for capturing waveform characteristics. The most important aspect of this process is the recent trend toward increased sampling rates and a greater number of digitized parameters per operation. The combined effect is a tremendous increase in output data volumes. Since digital signal processing carries the potential for significant contributions to manufacturing quality and reliability, as well as engineering design and development, increased activity in this area appears extremely desirable. 11 figures

Exploring the Variable Sky with the Sloan Digital Sky Survey

Energy Technology Data Exchange (ETDEWEB)

Sesar, Branimir; Ivezic, Zeljko; Lupton, Robert; Juric, Mario; Gunn, James; Knapp, Gillian; De Lee, Nathan; Smith, J. Allyn; Miknaitis,Gajus; Lin, Huan; Tucker, Douglas; Doi, Mamoru; Tanaka, Masayuki; Fukugita, Masataka; Holtzman, Jon; Kent, Steve; Yanny, Brian; Schlegel,David; Finkbeiner, Douglas; Padmanabhan, Nikhil; Rockosi, Constance; Bond, Nicholas; Lee, Brian; Stoughton, Chris; Jester, Sebastian; Harris,Hugh; Harding, Paul; Brinkmann, Jon; Schneider, Donald; York, Donald; Richmond, Michael; Vanden Berk, Daniel

2007-04-01

We quantify the variability of faint unresolved optical sources using a catalog based on multiple SDSS imaging observations. The catalog covers SDSS Stripe 82, which lies along the celestial equator in the Southern Galactic Hemisphere (22h 24m < {alpha}{sub J2000} < 04h 08m, -1.27{sup o} < {delta}{sub J2000} < +1.27{sup o}, {approx} 290 deg{sup 2}), and contains 58 million photometric observations in the SDSS ugriz system for 1.4 million unresolved sources that were observed at least 4 times in each of the gri bands (with a median of 10 observations obtained over {approx}5 years). In each photometric bandpass we compute various low-order lightcurve statistics such as root-mean-square scatter (rms), {chi}{sup 2} per degree of freedom, skewness, minimum and maximum magnitude, and use them to select and study variable sources. We find that 2% of unresolved optical sources brighter than g = 20.5 appear variable at the 0.05 mag level (rms) simultaneously in the g and r bands. The majority (2/3) of these variable sources are low-redshift (< 2) quasars, although they represent only 2% of all sources in the adopted flux-limited sample. We find that at least 90% of quasars are variable at the 0.03 mag level (rms) and confirm that variability is as good a method for finding low-redshift quasars as is the UV excess color selection (at high Galactic latitudes). We analyze the distribution of lightcurve skewness for quasars and find that is centered on zero. We find that about 1/4 of the variable stars are RR Lyrae stars, and that only 0.5% of stars from the main stellar locus are variable at the 0.05 mag level. The distribution of lightcurve skewness in the g-r vs. u-g color-color diagram on the main stellar locus is found to be bimodal (with one mode consistent with Algol-like behavior). Using over six hundred RR Lyrae stars, we demonstrate rich halo substructure out to distances of 100 kpc. We extrapolate these results to expected performance by the Large Synoptic Survey

The Evolution of Research on Digital Education

Science.gov (United States)

Dillenbourg, Pierre

2016-01-01

How does AI&EdAIED today compare to 25 years ago? This paper addresses this evolution by identifying six trends. The trends are ongoing and will influence learning technologies going forward. First, the physicality of interactions and the physical space of the learner became genuine components of digital education. The frontier between the…

Progress in digital radiography

International Nuclear Information System (INIS)

Cappelle, A.

2016-01-01

Because of its practical aspect digital radiography is more and more used in the industrial sector. There are 2 kinds of digital radiography. First, the 'computed radiography' that uses a photon-stimulated screen, and after radiation exposure this screen must be read by an analyser to get a digit image. The second type is the 'direct radiography' that allows one to get a digit radiograph of the object directly. Digital radiography uses the same radioactive nuclides as radiography with silver films: cobalt, iridium or selenium. The spatial resolution of digital radiography is less good than with classical silver film radiography but digital radiography offers a better visual contrast. (A.C.)

Do We Still Have a Digital Divide in Mental Health? A Five-Year Survey Follow-up.

Science.gov (United States)

Robotham, Dan; Satkunanathan, Safarina; Doughty, Lisa; Wykes, Til

2016-11-22

Nearly everyone in society uses the Internet in one form or another. The Internet is heralded as an efficient way of providing mental health treatments and services. However, some people are still excluded from using Internet-enabled technology through lack of resources, skills, and confidence. Five years ago, we showed that people with severe mental illness were at risk of digital exclusion, especially middle-aged patients with psychosis and/or people from black or minority ethnic groups with psychosis. An understanding of the breadth of potential digital exclusion is vital for the implementation of digital health services. The aim of this study is to understand the context of digital exclusion for people who experience mental illness. We conducted a survey involving people with a primary diagnosis of psychosis or depression in London, United Kingdom. A total of 241 participants were recruited: 121 with psychosis and 120 with depression. The majority of surveys were collected face-to-face (psychosis: n=109; depression: n=71). Participants answered questions regarding familiarity, access, use, motivation, and confidence with Internet-enabled technologies (ie, computers and mobile phones). Variables predicting digital exclusion were identified in regression analyses. The results were compared with the survey conducted in 2011. Digital exclusion has declined since 2011. Online survey collection introduced biases into the sample, masking those who were likely to be excluded. Only 18.3% (20/109) of people with psychosis in our sample were digitally excluded, compared with 30% (28/93) in 2011 (χ 2 1 =3.8, P=.04). People with psychosis had less confidence in using the Internet than people with depression (χ 2 1 =7.4, P=.004). Only 9.9% (24/241) of participants in the total sample were digitally excluded, but the majority of these people had psychosis (n=20). Those with psychosis who were digitally excluded were significantly older than their included peers (t 30 =3

Nebraska wind resource assessment first year results

Energy Technology Data Exchange (ETDEWEB)

Hurley, P.J.F.; Vilhauer, R. [RLA Consulting, Inc., Bothell, WA (United States); Stooksbury, D. [Univ. of Nebraska, Lincoln, NE (United States)

1996-12-31

This paper presents the preliminary results from a wind resource assessment program in Nebraska sponsored by the Nebraska Power Association. During the first year the measured annual wind speed at 40 meters ranged from 6.5 - 7.5 m/s (14.6 - 16.8 mph) at eight stations across the state. The site selection process is discussed as well as an overview of the site characteristics at the monitoring locations. Results from the first year monitoring period including data recovery rate, directionality, average wind speeds, wind shear, and turbulence intensity are presented. Results from the eight sites are qualitatively compared with other midwest and west coast locations. 5 figs., 2 tabs.

The Digital Divide: A Global View

Science.gov (United States)

Ntoko, Alexander

2011-04-01

Huge progress was made in bridging the digital divide in first decade of 21^st century. This was largely due to the explosive growth of mobile, which saw numbers rise from under 500 million to over five billion mobile cellular subscriptions in just ten years. With household mobile penetration rates of over 50% even in rural areas of developing countries, we have achieved the dream of bringing all the world's people within reach of communications technology. We must now, however, replicate the mobile miracle for the Internet, and especially broadband, if we are to avoid creating a new broadband breach to replace the digital divide. Three things need to happen for this to be achieved: firstly, broadband needs to be brought to the top of the development agenda; secondly, broadband needs to become much more affordable and thirdly, security needs to be part of the strategy.

Critically Evaluating Prensky in a Language Learning Context: The "Digital Natives/Immigrants Debate" and Its Implications for CALL

Science.gov (United States)

Benini, Silvia; Murray, Liam

2013-01-01

More than 10 years have passed since the first introduction of the term "digital natives" in Prensky's (2001a, 2001b) two seminal articles. Prensky argues that students today, having grown up in the Digital Age, learn differently from their predecessors, or "digital immigrants". As such, the pedagogical tools and methods used…

Help of third-year medical students decreases first-year medical students' negative psychological reactions on the first day of gross anatomy dissection.

Science.gov (United States)

Houwink, Aletta P; Kurup, Anil N; Kollars, Joshua P; Kral Kollars, Catharine A; Carmichael, Stephen W; Pawlina, Wojciech

2004-05-01

The assistance of third-year medical students (MS3) may be an easy, inexpensive, educational method to decrease physical and emotional stress among first-year medical students (MS1) on the first day of gross anatomy dissection. In the academic years 2000-2001 and 2001-2002, a questionnaire on the emotional and physical reactions on the first day of dissection was distributed to 84 MS1 at Mayo Medical School (Rochester, MN); 74 (88%) responded. Student perceptions were assessed on a 5-point Likert scale. The 42 second-year medical students (MS2) whose first academic year was 1999-2000 were used as a control group, because they had not had assistance from MS3. MS2 completed the same questionnaire (59% response rate). Data were collected from MS1 on the day of their first gross anatomy dissection. The most frequent reactions were headache, disgust, grief or sadness, and feeling light-headed. Significant differences (alpha vs. 88%), reporting lower levels of anxiety (23% vs. 48%), headache (14% vs. 36%), disgust (9% vs. 20%), feeling light-headed (11% vs. 24%), and reaction to the smell of the cadaver and laboratory (8% vs. 52%). MS1 commented that having MS3 at the dissection table was extremely helpful. They relied less on their peers and felt they learned more efficiently about the dissection techniques and anatomical structures. Using MS3 as assistants is one method to reduce fear and anxiety on the first day of gross anatomy dissection. Copyright 2004 Wiley-Liss, Inc.

University First Year Advisors: A network approach for first year student transition and retention. A Practice Report.

Directory of Open Access Journals (Sweden)

Geraldine Box

2012-03-01

Full Text Available Focussing expressly on student support and retention, improving the first year experience has been addressed by Murdoch University through the implementation of a School discipline-specific network of professional First Year Advisors (FYAs. FYA initiatives, both broad-based and varied, have been developed in alignment with the changing needs of students as identified throughout the semesters. A combination of outreach telephone campaigns and face-to-face student support enables FYAs to conduct a "just in time" approach to positively increase student engagement, and ultimately, retention. With a bespoke database, FYAs and academic staff have been able to streamline the process of reporting students in need of support, and gather data relating to student retention. The FYA program is yet to be formally evaluated although initial feedback and student consultation is promising. This paper outlines the program's development, current initiatives and expected outcomes.  

12-Year Use of a Digital Reference Library (VitalBook) at a U.S. Dental School: Students' and Alumni Perceptions.

Science.gov (United States)

Spielman, Andrew I; Maas, Elizabeth; Eisenberg, Elise S

2017-10-01

Digital textbooks are being used to reduce production and storage costs of printed copies, enhance usage, and include search capabilities, but the use of digital texts is not universally accepted. In 2001, the New York University College of Dentistry introduced a digital reference library, the VitalBook. Beginning in 2005, the college annually surveyed senior students and, from 2012, also surveyed alumni on their opinions and extent of use of the VitalBook. The aim of this study was to evaluate 12 years of students' perspectives and three years of alumni perspectives on the value of the VitalBook to their dental educational experience. Students were asked how frequently they used the VitalBook, if it was a good investment, if they would use it after graduation, and if they would recommend it to others. Alumni were asked the last three questions. This study reports the results from 4,105 students over 12 years (average response rate 95.3%) and 184 alumni over three years (average response rate 17.4%). The results indicated that students used the VitalBook on average 24% of their study time, but they were split regarding the other questions. The majority opinion in 2005 was negative on all questions. These opinions shifted to become more favorable to a peak in 2010, but declined since then to a more negative overall view of the VitalBook. A split opinion among students continued through 2016, with fewer recommending it although more considered it a good investment with plans to use it after graduation. Alumni mirrored their responses as students. These results suggest that, as more flexible and dynamic digitized reference systems emerge, the use of student-paid traditional digitized textbooks may become an even less favored choice.

Digital stethoscope: technology update

Science.gov (United States)

Swarup, Supreeya; Makaryus, Amgad N

2018-01-01

Cardiovascular disease (CVD) is recognized as the leading cause of mortality throughout the world. About one-third of global mortality is attributable to CVD. In addition to clinical presentation, specific clinical exam findings can assist in treating and preventing CVD. CVD may initially manifest as pulmonary pathology, and thus, accurate cardiopulmonary auscultation is paramount to establishing accurate diagnosis. One of the most powerful tools available to physicians is the stethoscope. The stethoscope first emerged in the year 1818, invented by a French physician, René Laennec. Since then, the initial modest monaural wooden tube has evolved into a sophisticated digital device. This paper provides an analysis of the evolution of the stethoscope as well as highlights the advancement made by the modern digital stethoscope including the application of this tool in advancing care for patients suffering from CVD. PMID:29379321

Young children's reading for pleasure with digital books: six key facets of engagement

OpenAIRE

Kucirkova, N.; Littleton, K.; Cremin, T.

2017-01-01

This paper offers a new characterisation of young children’s (2–8 years) reading for pleasure (RfP) with digital books. This characterisation is rooted in a re-contextualisation of Anna Craft’s conceptualisation of twenty-first century childhoods in Creativity and education futures (Stoke on Trent, Trentham, 2011) and a review of the literature concerning young children’s RfP with digital books. The paper develops Craft’s (2011) work by considering the ways in which digital books can resource...

The evaluation of first aid and basic life support training for the first year university students.

Science.gov (United States)

Altintaş, Kerim Hakan; Aslan, Dilek; Yildiz, Ali Naci; Subaşi, Nüket; Elçin, Melih; Odabaşi, Orhan; Bilir, Nazmi; Sayek, Iskender

2005-02-01

In Turkey, the first aiders are few in quantity and yet they are required in many settings, such as earthquakes. It was thought that training first year university students in first aid and basic life support (FA-BLS) techniques would serve to increase the number of first aiders. It was also thought that another problem, the lack of first aid trainers, might be addressed by training medical students to perform this function. A project aimed at training first year university students in FA-BLS was conducted at Hacettepe University. In the first phase, medical student first aid trainers (MeSFAT) were trained in FA-BLS training techniques by academic trainers and in the second phase, first year university students were trained in FA-BLS techniques by these peer trainers under the academic trainers' supervision. The purpose of this study was to assess the participants' evaluation of this project and to propose a new program to increase the number of first aiders in the country. In total, 31 medical students were certified as MeSFATs and 12 of these trained 40 first year university students in FA-BLS. Various questionnaires were applied to the participants to determine their evaluation of the training program. Most of the participants and the authors considered the program to be successful and effective. This method may be used to increase the number of first aid trainers and first aiders in the community.

Future approaches to digital systems

International Nuclear Information System (INIS)

Woodrough, R.E.; Beckmann, E.; Jenkins, D.; Belcher, D.

1984-01-01

The introduction of the first digital imaging systems has led to the concept of a totally digital imaging department - the 'filmless department'. This concept and its associated network system for digital departments are briefly considered. A transducer system of scanned projection radiography with solid state detectors used in digital chest imaging is described. The principles of this transducer system are applicable to other forms of digital radiography. (U.K.)

Progress in the capture, manipulation, and delivery of medical media and its impact on education, clinical care, and research.

Science.gov (United States)

Bernardo, Theresa M; Malinowski, Robert P

2005-01-01

In this article, advances in the application of medical media to education, clinical care, and research are explored and illustrated with examples, and their future potential is discussed. Impact is framed in terms of the Sloan Consortium's five pillars of quality education: access; student and faculty satisfaction; learning effectiveness; and cost effectiveness. (Hiltz SR, Zhang Y, Turoff M. Studies of effectiveness of learning networks. In Bourne J, Moore J, ed. Elements of Quality Online Education. Needham, MA: Sloan-Consortium, 2002:15-45). The alternatives for converting analog media (text, photos, graphics, sound, video, animations, radiographs) to digital media and direct digital capture are covered, as are options for storing, manipulating, retrieving, and sharing digital collections. Diagnostic imaging is given particular attention, clarifying the difference between computerized radiography and digital radiography and explaining the accepted standard (DICOM) and the advantages of Web PACS. Some novel research applications of medical media are presented.

Improving academic achievement after First year Studentship in the ...

African Journals Online (AJOL)

The study therefore recommended that the negative experiences should be part of the orientation given to first year students in the University. Second, that universities should not use the grade point average obtained during the first year to compute the final GPA for graduating students. Keywords:Academic Achievement ...

Oral piercings among first-year university students.

Science.gov (United States)

Ventä, Irja; Lakoma, Ani; Haahtela, Sauli; Peltola, Jaakko; Ylipaavalniemi, Pekka; Turtola, Lauri

2005-05-01

The aim of the study was to examine oral piercings among first-year university students. First-year university students in 2002 were invited to a dental examination (n = 234; 49 men and 185 women). Students with piercings formed the study group and the rest served as controls. The methods included decayed, missing, and filled teeth (DMF) index, stimulated salivary flow rates, panoramic tomograms, and questionnaires including the Depression Inventory of Beck. Fisher's 2-sided exact test was used for statistical analysis. The prevalence of oral piercings was 3.4%. In the DMF indices, no statistically significant differences existed between the groups. Increased salivary flow rates were noted among students with piercings (63% vs 26%, P piercings is essential.

Digital library programs for libraries and archives developing, managing, and sustaining unique digital collections

CERN Document Server

Purcell, D

2016-01-01

Equally valuable for LIS students just learning about the digital landscape, information professionals taking their first steps to create digital content, and organizations who already have well-established digital credentials, Purcell's book outlines methods applicable and scalable to many different types and sizes of libraries and archives.

A sample of galaxy pairs identified from the LAMOST spectral survey and the Sloan Digital Sky Survey

International Nuclear Information System (INIS)

Shen, Shi-Yin; Argudo-Fernández, Maria; Chen, Li; Feng, Shuai; Hou, Jin-Liang; Shao, Zheng-Yi; Chen, Xiao-Yan; Luo, A-Li; Wu, Hong; Yang, Hai-Feng; Yang, Ming; Hou, Yong-Hui; Wang, Yue-Fei; Jiang, Peng; Wang, Ting-Gui; Jing, Yi-Peng; Kong, Xu; Wang, Wen-Ting; Luo, Zhi-Jian; Wu, Xue-Bing

2016-01-01

A small fraction (< 10%) of the SDSS main galaxy (MG) sample has not been targeted with spectroscopy due to the effect of fiber collisions. These galaxies have been compiled into the input catalog of the LAMOST ExtraGAlactic Surveys and named the complementary galaxy sample. In this paper, we introduce this project and status of the spectroscopies associated with the complementary galaxies in the first two years of the LAMOST spectral survey (till Sep. of 2014). Moreover, we present a sample of 1102 galaxy pairs identified from the LAMOST complementary galaxies and SDSS MGs, which are defined as two members that have a projected distance smaller than 100 h −1 70 kpc and a recessional velocity difference smaller than 500 km s −1 . Compared with galaxy pairs that are only selected from SDSS, the LAMOST-SDSS pairs have the advantages of not being biased toward large separations and therefore act as a useful supplement in statistical studies of galaxy interaction and galaxy merging. (paper)

Digital Enlightenment Yearbook 2012

CERN Document Server

Bus, J; Hildebrandt, M

2012-01-01

There have been many inevitable transformations in society due to digitization - the introduction of digital technology, including communication technology, through the Internet and its use via the Web.This book is the first Yearbook of the Digital Enlightenment Forum. Whilst it cannot cover all the many aspects which the forum encompasses, the book gives an impression of the broad spectrum of the forum and a clear picture of the multi-disciplinary nature of the issues at stake.The first paper in the book is a contribution from the father of the Web, Sir Tim Berners-Lee, and Harry Halpin. They

Time to Engage? Texting to Support and Enhance First Year Undergraduate Learning

Directory of Open Access Journals (Sweden)

Geraldine Jones

2009-04-01

Full Text Available In this paper we discuss a case study investigating how the academic and personal development of first year students on an undergraduate sports education degree can be supported and enhanced with mobile SMS communication. SMS-based technologies were introduced in response to students’ particular needs (in transition to Higher Education and characteristics (‘digital natives’. Despite being unaccustomed to using their mobile phones for academic study, students willingly participated in SMS communication with their tutor via a texting management service. Drawing on evidence from two student surveys, focus groups and a tutor’s journal, we illustrate the potential that mobile SMS communication has to link and establish continuity between face to face teaching sessions and online learning activities in the Virtual Learning Environment (VLE. Many students perceived the SMS communication to have had a positive impact on their management of study time. We link our findings with the existing literature and argue that mobile text based communication has the potential to support the development of time management skills, an important component of self regulatory learning, a skill which has been shown to be key in making a successful transition.

Race, Late Bloomers and First-Year GPA: Predicting beyond the Freshman Year

Science.gov (United States)

Gayles, Jonathan

2012-01-01

First-year grade point average (FYGPA) is an oft-referenced outcome criterion for assessments of the predictive validity of a variety of admissions mechanisms. Unfortunately, few studies examine the relationship between FYGPA and long-term outcomes such as graduating grade point average and six-year graduation. Influenced by Wilson's (1980)…

First results of MAO NASU SS bodies photographic archive digitizing

Science.gov (United States)

Pakuliak, L.; Andruk, V.; Shatokhina, S.; Golovnya, V.; Yizhakevych, O.; Kulyk, I.

2013-05-01

MAO NASU glass archive encloses about 1800 photographic plates with planets and their satellites (including near 80 images of Uranus, Pluto and Neptune), about 1700 plates with minor planets and about 900 plates with comets. Plates were made during 1949-1999 using 11 telescopes of different focus, mostly the Double Wide-angle Astrograph (F/D=2000/400) and the Double Long-focus Astrograph (F/D=5500/400) of MAO NASU. Observational sites are Kyiv, Lviv (Ukraine), Biurakan (Armenia), Abastumani (Georgia), Mt. Maidanak (Uzbekistan), Quito (Equador). Tables contain data about the most significant numbers of plates sub-divided by years and objects. The database with metadata of plates (DBGPA) is available on the computer cluster of MAO (http://gua.db.ukr-vo.org) via open access. The database accumulates archives of four Ukrainian observatories, involving the UkrVO national project. Together with the archive managing system, the database serves as a test area for JDA - Joint Digital Archive - the core of the UkrVO.

A Mathematics Support Programme for First-Year Engineering Students

Science.gov (United States)

Hillock, Poh Wah; Jennings, Michael; Roberts, Anthony; Scharaschkin, Victor

2013-01-01

This article describes a mathematics support programme at the University of Queensland, targeted at first-year engineering students identified as having a high risk of failing a first-year mathematics course in calculus and linear algebra. It describes how students were identified for the programme and the main features of the programme. The…

"MathePraxis"--Connecting First-Year Mathematics with Engineering Applications

Science.gov (United States)

Harterich, Jorg; Kiss, Christine; Rooch, Aeneas; Monnigmann, Martin; Darup, Moritz Schulze; Span, Roland

2012-01-01

First-year engineering students often complain about their mathematics courses as the significance of the difficult and abstract calculus to their field of study remains unclear. We report on the project "MathePraxis", a feasibility study which was designed as a means to give first-year students some impression about the use of…

Combined First-Trimester Screening in Northern Finland: Experiences of the First Ten Years

Directory of Open Access Journals (Sweden)

Merilainen Anna

2014-01-01

Full Text Available Objective To evaluate the efficacy of first trimester combined screening for Down's syndrome in Northern Finland during the first 10 years of practice. Methods During 1 January 2002 to 31 December 2011, 47,896 women participated voluntarily in combined screening during first trimester. The risk cutoff was 1:250. The study period was divided into two time periods; 2002-2006 and 2007-2011. Results During the first half of the study period, the detection rate (DR was 77.3% with a 4.9% false-positive rate (FPR. During the latter half, the DR was 77.1% with a 2.8% FPR. Conclusions An important issue is the number of invasive procedures needed to detect one case of Down's syndrome. The screening performance improved markedly in the latter five years period since the FPR lowered from 4.9% to 2.8% and the number of invasive procedures needed to detect one case of Down's syndrome lowered from 15 to 11.

Decreasing Authority Dependence during the First Year of College

Science.gov (United States)

Magolda, Marcia B. Baxter; King, Patricia M.; Taylor, Kari B.; Wakefield, Kerri M.

2012-01-01

Annual interviews with 228 students at 6 diverse campuses in the Wabash National Study of Liberal Arts Education reveal 123 students' developmental growth away from authority dependence between the beginning of the first and second years of college. In the first year of college, 86% of participants relied solely on external authorities to define…

Students' perceptions and expectations of a first-year psychology ...

African Journals Online (AJOL)

The purpose of this study was to explore students' expectations and perceptions of a first-year Psychology course (Psyc 100) at the University of the North. The idea of obtaining information about the students' opinions (especially from those in their first year of study) was spurred by the realisation that students can usefully ...

Digital radiography

International Nuclear Information System (INIS)

Kusano, Shoichi

1993-01-01

Firstly, from an historic point of view, fundamental concepts on digital imaging were reviewed to provide a foundation for discussion of digital radiography. Secondly, this review summarized the results of ongoing research in computed radiography that replaces the conventional film-screen system with a photo-stimulable phosphor plate; and thirdly, image quality, radiation protection, and image processing techniques were discussed with emphasis on picture archiving and communication system environment as our final goal. Finally, future expansion of digital radiography was described based on the present utilization of computed tomography at the National Defense Medical College Hospital. (author) 60 refs

Organisational aspects of mammography screening in digital settings: First experiences of Luxembourg

International Nuclear Information System (INIS)

Shannoun, F.; Schanck, J. M.; Scharpantgen, A.; Wagnon, M. C.; Ben Daoud, M.; Back, C.

2008-01-01

Luxembourg has been conducting a breast cancer screening programme since 1992, like a large number of other European countries, as early detection and treatment of breast cancer have been proven to reduce mortality. The majority of these screening programmes are based on analogue X-ray technology and have optimised their organisation of transporting, archiving and reading with respect to films. Last decade is marked by enormous developments in digital mammography. Different technologies such as flat panel-, computed radiography- and scanning systems became available. Digital mammography is expected to have a major impact on quality and organisation of breast cancer screening programmes. Screening programmes are now faced with a huge challenge of incorporating the digital technology, including implementation of electronic image exchange, conception of new electronic work-flow, establishing adapted quality assurance programmes and training of radiologists and technical personnel. Initial experiences of the Luxembourg approach in organising digital mammography screening and its quality assurance are reported. (authors)

Redefining Student Affairs through Digital Technology: A Ten-Year Historiography of Digital Technology Use by Student Affairs Administrators

Science.gov (United States)

Cabellon, Edmund T.

2016-01-01

The student affairs profession is at a crossroads (Torres & Walbert, 2010) given digital technology's growth and the academy's administrative expansion (Bowen, 2013). Student affairs administrators must simultaneously respond to digital technology's implications in students' lives (Kirschner & Karpinski, 2010) and to new state and federal…

Focusing on first year assessment: Surface or deep approaches to learning?

Directory of Open Access Journals (Sweden)

Sharn Donnison

2012-08-01

Full Text Available This paper investigates the assessment and learning approaches that some first year students employ to assist them in their transition into their first year of study and extends our previous work on first year student engagement and timely academic support (Penn-Edwards & Donnison, 2011. It is situated within the First Year transition and student engagement literature and specifically speaks to concepts of learning within that body of literature. In this paper we argue that while students are in the transitional period of their studies, the use of assessment as a motivator for learning (surface approach is valid first year pedagogy and forms an initial learning stage in the student’s progress towards being lifelong learners. 

Existential space understanding through digital image

Directory of Open Access Journals (Sweden)

Susana Iñarra Abad

2013-10-01

Full Text Available The logical way to learn from the architectural space and then be able to design and represent it is, undoubtedly, that of experiencing it through all the sensitive channels that the space wakes up us.  But since the last 30 years, much of our learning about space comes from images of architecture and not from the space itself. The art of architecture is drifting towards a visual art and moving away from its existential side. In digital images that have flooded the architectural media, digital photographs of existing spaces intermingle with non-existent space renderings (photographs with a virtual camera. The first ones represent existing places but can be altered to change the perception that  the observer of the image will have, the second ones speak to us about places that do not exist yet but they present reality portions through extracts from digital photography (textures, trees, people... that compose the image.

Opportunity to Learn First Year Mathematics in Teacher Training ...

African Journals Online (AJOL)

kofimereku

first year teacher training mathematics syllabus were not taught by the end of the year and which ones were ... In the teacher training colleges in Ghana, Mathematics is studied as a compulsory subject in the first and .... as well as provide a 'search device', when an inquiry is beginning (Babbie,. 1990). The main focus in this ...

Exploring the potential of digital resources as a source of social support in first time pregnancy

Directory of Open Access Journals (Sweden)

Nikki Newhouse

2015-10-01

First-time pregnancy is a time of huge physical and emotional change and women often need support. One way of providing this is to provide wellbeing information. However, pregnant women are bombarded with information, much of it generic, conflicting or anecdotal. Large numbers of women look for information and advice online, increasingly engaging with alternative forms of ‘expert’ information, in the form of other people’s experiences. This context provides a unique opportunity for digital resources to act as preventative medicine: bringing women together in a safe online environment allows them to speak freely, develop practical skills and feel supported as they become parents. This in turn relieves healthcare burden by preventing negative maternal and neonatal outcomes. This project will determine the context-driven user needs and requirements of a unique group of people and demonstrates the importance of a multidisciplinary approach to the development of pragmatic digital health solutions.

Is the Memorial Sloan Kettering Cancer Centre (MSKCC) sarcoma nomogram useful in an Asian population?

Science.gov (United States)

Ng, Deanna Wan Jie; Tan, Grace Hwei Ching; Chia, Claramae Shulyn; Lim, Cindy Xindi; Chee, Soo Khee; Quek, Richard Hong Hui; Farid, Mohamad; Teo, Melissa Ching Ching

2017-10-01

A nomogram for prediction of 12-year sarcoma-specific survival has been developed based on patients with soft tissue sarcomas treated in Memorial Sloan Kettering Cancer Centre (MSKCC). We aim to evaluate the predictive accuracy of the MSKCC sarcoma nomogram in a cohort of patients treated at an Asian institution. This has not been validated in an Asian population and thus its universal applicability remains unproven. Between 1990 and 2013, 840 adult patients underwent treatment for primary soft tissue sarcoma (STS) at the National Cancer Centre Singapore. Patients who presented with locally recurrent or metastatic disease were excluded from the analysis. The variables included in the MSKCC nomogram included age at diagnosis, tumor size, histologic grade, histologic subtype, depth and site. A total of 399 patients were left for analysis. The nomogram was validated by assessing its extent of discrimination and level of calibration. All patients had deep tumors. Disease occurred most commonly in the lower extremity (n = 149 [37.3%]), the most common histologic subtype was "Others" (angiosarcoma, ewing's sarcoma, endometrial stromal sarcoma, sarcoma NOS [not otherwise specified] and rhabdomyosarcoma). Sixty-four percent of all patients had high-grade tumors while 36% had low-grade tumors. The median patient age at diagnosis was 54 years (range: 17-88 years). The median follow up time for all patients and surviving patients were 29 (range: 1-174) and 33 (range: 1-157) months, respectively. The observed 5- and 10-year sarcoma-specific survival were 55% and 33%, respectively. The concordance index was 0.71. For level of calibration, the observed correspondence between predicted and actual outcomes suggest that the MSKCC nomogram generally predicts well for patients with higher survival probability, but consistently overpredicts survival for the other groups, in our cohort of patients. The MSKCC sarcoma nomogram was found to be accurate in terms of extent of discrimination

Can we continue to effectively police digital crime?

Science.gov (United States)

Horsman, Graeme

2017-11-01

Now approximately 30years old, the field of digital forensics is arguably facing some of its greatest challenges to date. Whilst currently supporting law enforcement in numerous criminal cases annually, questions are beginning to emerge regarding whether it can sustain this contribution, with digital crime remaining prevalent. In his first live interview in September 2015, Head of MI5, Andrew Parker indicated that individuals are now engaging in computing acts which are beyond the control of authorities, confirming earlier remarks made by British Prime Minister David Cameron in the wake of the Charlie Hebdo attacks. Such comments cast doubt on the future effectiveness of the digital forensic discipline and its ability to effectively investigate those who implement the latest forms of technology to carry out illicit acts. This article debates the controversial question, could we be facing an era where digital crime can no longer be effectively policed? Copyright © 2017 The Chartered Society of Forensic Sciences. Published by Elsevier B.V. All rights reserved.

First-Year Female Students: Perceptions of Friendship.

Science.gov (United States)

Ishler, Jennifer L. Crissman; Schreiber, Staci

2002-01-01

Examined 91 first-year female students' perceptions of their pre-college and new collegiate friendships. Found that they have difficulty letting go of pre-college friendships and investing in new friendships. (EV)

The impact of specially designed digital games-based learning in undergraduate pathology and medical education.

Science.gov (United States)

Kanthan, Rani; Senger, Jenna-Lynn

2011-01-01

The rapid advances of computer technologies have created a new e-learner generation of "Homo-zappien" students that think and learn differently. Digital gaming is an effective, fun, active, and encouraging way of learning, providing immediate feedback and measurable process. Within the context of ongoing reforms in medical education, specially designed digital games, a form of active learning, are effective, complementary e-teaching/learning resources. To examine the effectiveness of the use of specially designed digital games for student satisfaction and for measurable academic improvement. One hundred fourteen students registered in first-year pathology Medicine 102 had 8 of 16 lecture sessions reviewed in specially designed content-relevant digital games. Performance scores to relevant content sessions were analyzed at midterm and final examinations. Seventy-one students who registered in second-year pathology Medicine 202 were exposed to the games only during the final examination, with the midterm examination serving as an internal matched-control group. Outcome measures included performance at midterm and final examinations. Paired 2-tailed t test statistics compared means. A satisfaction survey questionnaire of yes or no responses analyzed student engagement and their perceptions to digital game-based learning. Questions relevant to the game-play sessions had the highest success rate in both examinations among 114 first-year students. In the 71 second-year students, the examination scores at the end of the final examination were significantly higher than the scores on the midterm examination. Positive satisfaction survey noted increased student engagement, enhanced personal learning, and reduced student stress. Specially constructed digital games-based learning in undergraduate pathology courses showed improved academic performance as measured by examination test scores with increased student satisfaction and engagement.

Searching early bone metastasis on plain radiography by using digital imaging processing

Energy Technology Data Exchange (ETDEWEB)

Jaramillo-Nunez, A.; Perez-Meza, M. [Instituto Nacional de Astrofisica, Optica y Electronica, Apdo. Postal 51 y 216, Pue. (Mexico); Universidad de la Sierra Sur, C. P. 70800, Miahuatlan, Oax. (Mexico)

2012-10-23

Some authors mention that it is not possible to detect early bone metastasis on plain radiography. In this work we use digital imaging processing to analyze three radiographs taken from a patient with bone metastasis discomfort on the right shoulder. The time period among the first and second radiography was approximately one month and between the first and the third one year. This procedure is a first approach in order to know if in this particular case it was possible to detect an early bone metastasis. The obtained results suggest that by carrying out a digital processing is possible to detect the metastasis since the radiography contains the information although visually it is not possible to observe it.

26 CFR 1.168(k)-1 - Additional first year depreciation deduction.

Science.gov (United States)

2010-04-01

... 26 Internal Revenue 2 2010-04-01 2010-04-01 false Additional first year depreciation deduction. 1... Corporations § 1.168(k)-1 Additional first year depreciation deduction. (a) Scope and definitions—(1) Scope. This section provides the rules for determining the 30-percent additional first year depreciation...

Mentoring and Retention in First-Year Teachers: A Mixed-Methods Study

Science.gov (United States)

Morina, Sam F., Jr.

2010-01-01

This study collected relevant information from first-year teacher proteges about mentorship effectiveness and anticipated turnover. The primary goal of this study was to examine a first-year-teacher mentoring program to determine its perceived effectiveness for first-year-teacher proteges and to examine their perceptions of the essential…

The first forty years, 1947-1987

International Nuclear Information System (INIS)

Rowe, M.S.; Cohen, A.; Petersen, B.

1987-01-01

This report commemorates the fortieth anniversary of Brookhaven National Laboratory by representing a historical overview of research at the facility. The chapters of the report are entitled: The First Forty Years, Brookhaven: A National Resource, Fulfilling a Mission - Brookhaven's Mighty Machines, Marketing the Milestones in Basic Research, Meeting National Needs, Making a Difference in Everyday Life, and Looking Forward

The Relationship between Student Performance in a First Year ...

African Journals Online (AJOL)

In 2001, the University of Zimbabwe doubled the intake into first year at the request of the government. An analysis of one affected course, Plant Biology of the first year of the BSc Honours in Agriculture Degree, was carried out due to the high failure rate (39%). There was also a failure rate of 44% for those students with less ...

Digital displacements

DEFF Research Database (Denmark)

Pors, Anja Svejgaard

2014-01-01

In recent years digital reforms are being introduced in the municipal landscape of Denmark. The reforms address the interaction between citizen and local authority. The aim is, that by 2015 at least 80 per cent of all correspondence between citizens and public authority will be transmitted through...... digital interface. However, the transformation of citizen services from traditional face-to-face interaction to digital self-service gives rise to new practices; some citizens need support to be able to manage self-service through digital tools. A mixture of support and teaching, named co......-service, is a new task in public administration, where street level bureaucrats assist citizens in using the new digital solutions. The paper is based on a case study conducted primarily in a citizen service centre in Copenhagen, Denmark. Based on ethnography the paper gives an empirical account of the ongoing...

Digital Badges and Library Instructional Programs: Academic Library Case Study

Science.gov (United States)

Rodgers, Andrea Reed; Puterbaugh, Mark

2017-01-01

This case study describes the planning, implementation, and migration process of Eastern University Library's information literacy digital badge. Prior to implementing a badging program, information literacy sessions were informally embedded in first-year college writing courses as a "one-shot" presentation. Spurred on by accreditation…

Digital Humanities

DEFF Research Database (Denmark)

Brügger, Niels

2016-01-01

, and preserving material to study, as an object of study in its own right, as an analytical tool, or for collaborating, and for disseminating results. The term "digital humanities" was coined around 2001, and gained currency within academia in the following years. However, computers had been used within......Digital humanities is an umbrella term for theories, methodologies, and practices related to humanities scholarship that use the digital computer as an integrated and essential part of its research and teaching activities. The computer can be used for establishing, finding, collecting...

First-Year Residents Outperform Third-Year Residents after Simulation-Based Education in Critical Care Medicine

Science.gov (United States)

Singer, Benjamin D.; Corbridge, Thomas C.; Schroedl, Clara J.; Wilcox, Jane E.; Cohen, Elaine R.; McGaghie, William C.; Wayne, Diane B.

2012-01-01

Introduction Prior research shows that gaps exist in internal medicine residents’ critical care knowledge and skills. The purpose of this study was to compare the bedside critical care competency of first-year residents who received a simulation-based educational intervention plus clinical training to third-year residents who received clinical training alone. Methods During their first three months of residency, a group of first-year residents completed a simulation-based educational intervention. A group of traditionally-trained third-year residents who did not receive simulation-based training served as a comparison group. Both groups were evaluated using a 20-item clinical skills assessment at the bedside of a patient receiving mechanical ventilation at the end of their medical intensive care unit rotation. Scores on the skills assessment were compared between groups. Results Simulator-trained first-year residents (n=40) scored significantly higher compared to traditionally-trained third-year residents (n=27) on the bedside assessment, 91.3% (95% CI 88.2% to 94.3%) vs. 80.9% (95% CI 76.8% to 85.0%), P = simulation-based educational intervention demonstrated higher clinical competency than third-year residents who did not undergo simulation training. Critical care competency cannot be assumed after clinical ICU rotations; simulation-based curricula can help ensure residents are proficient to care for critically ill patients. PMID:23222546

Accessible Geoscience - Digital Fieldwork

Science.gov (United States)

Meara, Rhian

2017-04-01

Accessible Geoscience is a developing field of pedagogic research aimed at widening participation in Geography, Earth and Environmental Science (GEES) subjects. These subjects are often less commonly associated with disabilities, ethnic minorities, low income socio-economic groups and females. While advancements and improvements have been made in the inclusivity of these subject areas in recent years, access and participation of disabled students remains low. While universities are legally obligated to provide reasonable adjustments to ensure accessibility, the assumed incompatibility of GEES subjects and disability often deters students from applying to study these courses at a university level. Instead of making reasonable adjustments if and when they are needed, universities should be aiming to develop teaching materials, spaces and opportunities which are accessible to all, which in turn will allow all groups to participate in the GEES subjects. With this in mind, the Swansea Geography Department wish to enhance the accessibility of our undergraduate degree by developing digital field work opportunities. In the first instance, we intend to digitise three afternoon excursions which are run as part of a 1st year undergraduate module. Each of the field trips will be digitized into English- and Welsh-medium formats. In addition, each field trip will be digitized into British Sign Language (BSL) to allow for accessibility for D/deaf and hard of hearing students. Subtitles will also be made available in each version. While the main focus of this work is to provide accessible fieldwork opportunities for students with disabilities, this work also has additional benefits. Students within the Geography Department will be able to revisit the field trips, to revise and complete associated coursework. The use of digitized field work should not replace opportunities for real field work, but its use by the full cohort of students will begin to "normalize" accessible field

Exploring digital professionalism.

Science.gov (United States)

Ellaway, Rachel H; Coral, Janet; Topps, David; Topps, Maureen

2015-01-01

The widespread use of digital media (both computing devices and the services they access) has blurred the boundaries between our personal and professional lives. Contemporary students are the last to remember a time before the widespread use of the Internet and they will be the first to practice in a largely e-health environment. This article explores concepts of digital professionalism and their place in contemporary medical education, and proposes a series of principles of digital professionalism to guide teaching, learning and practice in the healthcare professions. Despite the many risks and fears surrounding their use, digital media are not an intrinsic threat to medical professionalism. Professionals should maintain the capacity for deliberate, ethical, and accountable practice when using digital media. The authors describe a digital professionalism framework structured around concepts of proficiency, reputation, and responsibility. Digital professionalism can be integrated into medical education using strategies based on awareness, alignment, assessment, and accountability. These principles of digital professionalism provide a way for medical students and medical practitioners to embrace the positive aspects of digital media use while being mindful and deliberate in its use to avoid or minimize any negative consequences.

3 GHz digital rf control at the superconducting Darmstadt electron linear accelerator: First results from the baseband approach and extensions for other frequencies

Directory of Open Access Journals (Sweden)

A. Araz

2010-08-01

Full Text Available The low level rf system for the superconducting Darmstadt electron linear accelerator (S-DALINAC developed 20 years ago and operating since converts the 3 GHz signals from the cavities down to the baseband and not to an intermediate frequency. While designing the new, digital rf control system this concept was kept: the rf module does the I/Q and amplitude modulation/demodulation while the low frequency board, housing an field programmable gate array analyzes and processes the signals. Recently, the flexibility of this concept was realized: By replacing the modulator/demodulators on the rf module, cavities operating at frequencies other than the one of the S-DALINAC can be controlled with only minor modifications: A 6 GHz version, needed for a harmonic bunching system at the S-DALINAC and a 324 MHz solution to be used on a room temperature cavity at GSI, are currently under design. This paper reviews the concept of the digital low level rf control loops in detail and reports on the results gained during first operation with a superconducting cavity.

The first forty years, 1947-1987

Energy Technology Data Exchange (ETDEWEB)

Rowe, M.S. (ed.); Cohen, A.; Petersen, B.

1987-01-01

This report commemorates the fortieth anniversary of Brookhaven National Laboratory by representing a historical overview of research at the facility. The chapters of the report are entitled: The First Forty Years, Brookhaven: A National Resource, Fulfilling a Mission - Brookhaven's Mighty Machines, Marketing the Milestones in Basic Research, Meeting National Needs, Making a Difference in Everyday Life, and Looking Forward.

Building Connections in the First-year Undergraduate Experience

Directory of Open Access Journals (Sweden)

June Countryman

2013-12-01

Full Text Available Concerned about the success rate of new students in our program we designed and implemented a compulsory set of experiences which aim to support students in their transition from high school to university by 1 developing their sense of belonging to a community of learners and by 2 articulating with them the interrelationships among their first year core courses. We initiated various strategies which we have refined in response to student feedback over the past three years. In this paper we describe the pedagogical moves that constitute our initiative and the lessons we learned. We explore essential academic and personal issues that first-year students in all programs face. We share our research findings and address the big ideas that could be applied to any discipline or multi-disciplinary program.

Psychosocial Factors Predicting First-Year College Student Success

Science.gov (United States)

Krumrei-Mancuso, Elizabeth J.; Newton, Fred B.; Kim, Eunhee; Wilcox, Dan

2013-01-01

This study made use of a model of college success that involves students achieving academic goals and life satisfaction. Hierarchical regressions examined the role of six psychosocial factors for college success among 579 first-year college students. Academic self-efficacy and organization and attention to study were predictive of first semester…

Engaging Beyond the First College Year: Exploring the Needs of Second-year Students

Directory of Open Access Journals (Sweden)

Elizabeth L. Black

2014-12-01

Full Text Available This article makes the case for librarians to engage with second-year students as part of the burgeoning movement in higher education to provide dedicated programming and experiences for second-year students. Grounded in development theories and transition theory, the article describes the special needs characteristic of typical second-year students and how librarians can build on the excellent work in first-year programs to collaborate with campus colleagues to further information literacy instruction.

Digital printing

Science.gov (United States)

Sobotka, Werner K.

1997-02-01

Digital printing is described as a tool to replace conventional printing machines completely. Still this goal was not reached until now with any of the digital printing technologies to be described in the paper. Productivity and costs are still the main parameters and are not really solved until now. Quality in digital printing is no problem anymore. Definition of digital printing is to transfer digital datas directly on the paper surface. This step can be carried out directly or with the use of an intermediate image carrier. Keywords in digital printing are: computer- to-press; erasable image carrier; image carrier with memory. Digital printing is also the logical development of the new digital area as it is pointed out in Nicholas Negropotes book 'Being Digital' and also the answer to networking and Internet technologies. Creating images text and color in one country and publishing the datas in another country or continent is the main advantage. Printing on demand another big advantage and last but not least personalization the last big advantage. Costs and being able to coop with this new world of prepress technology is the biggest disadvantage. Therefore the very optimistic growth rates for the next few years are really nonexistent. The development of complete new markets is too slow and the replacing of old markets is too small.

Faster processing of multiple spatially-heterodyned direct to digital holograms

Science.gov (United States)

Hanson, Gregory R [Clinton, TN; Bingham, Philip R [Knoxville, TN

2008-09-09

Systems and methods are described for faster processing of multiple spatially-heterodyned direct to digital holograms. A method includes of obtaining multiple spatially-heterodyned holograms, includes: digitally recording a first spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis; digitally recording a second spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis; Fourier analyzing the recorded first spatially-heterodyned hologram by shifting a first original origin of the recorded first spatially-heterodyned hologram including spatial heterodyne fringes in Fourier space to sit on top of a spatial-heterodyne carrier frequency defined as a first angle between a first reference beam and a first object beam; applying a first digital filter to cut off signals around the first original origin and performing an inverse Fourier transform on the result; Fourier analyzing the recorded second spatially-heterodyned hologram by shifting a second original origin of the recorded second spatially-heterodyned hologram including spatial heterodyne fringes in Fourier space to sit on top of a spatial-heterodyne carrier frequency defined as a second angle between a second reference beam and a second object beam; and applying a second digital filter to cut off signals around the second original origin and performing an inverse Fourier transform on the result, wherein digitally recording the first spatially-heterodyned hologram is completed before digitally recording the second spatially-heterodyned hologram and a single digital image includes both the first spatially-heterodyned hologram and the second spatially-heterodyned hologram.

Factors affecting Mathematics achievement of first-year secondary ...

African Journals Online (AJOL)

This study explores the sources of variability in Mathematics achievement of Ugandan students at the student, classroom and school level. The Mathematics score and questionnaire responses of 4,819 first-year secondary school students (Grade Seven, about 14-15 years old) from 78 classrooms of 49 schools were ...

Public Access to Digital Material; A Call to Researchers: Digital Libraries Need Collaboration across Disciplines; Greenstone: Open-Source Digital Library Software; Retrieval Issues for the Colorado Digitization Project's Heritage Database; Report on the 5th European Conference on Digital Libraries, ECDL 2001; Report on the First Joint Conference on Digital Libraries.

Science.gov (United States)

Kahle, Brewster; Prelinger, Rick; Jackson, Mary E.; Boyack, Kevin W.; Wylie, Brian N.; Davidson, George S.; Witten, Ian H.; Bainbridge, David; Boddie, Stefan J.; Garrison, William A.; Cunningham, Sally Jo; Borgman, Christine L.; Hessel, Heather

2001-01-01

These six articles discuss various issues relating to digital libraries. Highlights include public access to digital materials; intellectual property concerns; the need for collaboration across disciplines; Greenstone software for construction and presentation of digital information collections; the Colorado Digitization Project; and conferences…

Transforming the First Year of College for Students of Color. The First-Year Experience Monograph Series No. 38

Science.gov (United States)

Rendon, Laura I., Ed.; Garcia, Mildred, Ed.; Person, Dawn, Ed.

2004-01-01

"Transforming the First Year of College for Students of Color" addresses some of the unique challenges and transition issues for African-American, Latino/a, Asian-Pacific American, American Indian/Alaska Native, and multiracial college students. Chapters address specific strategies for working with these student populations to ensure their success…

Leading Learning: First-Year Principals' Reflections on Instructional Leadership

Science.gov (United States)

O'Doherty, Ann; Ovando, Martha N.

2013-01-01

This qualitative study examined the instructional leadership perceptions of four first-year principals. Findings illuminate five themes drawn from the data: definitions of instructional leadership, challenges that first-year principals faced, how these principals addressed these challenges, how the novice principals plan to enact their…

Monitoring the digital divide

International Nuclear Information System (INIS)

Canessa, E.; Cerdeira, H.A.; Matthews, W.; Cottrell, R.L.

2003-05-01

It is increasingly important to support the large numbers of scientists working in remote areas and having low-bandwidth access to the Internet. This will continue to be the case for years to come since there is evidence from PingER performance measurements that the, so-called, digital divide is not decreasing. In this work, we review the collaborative work of The Abdus Salam International Center for Theoretical Physics (ICTP) in Trieste - a leading organization promoting science dissemination in the developing world- and SLAC in Stanford, to monitor by PingER, Universities and Research Institutions all over the developing world following the recent 'Recommendations of Trieste' to help bridge the digital divide. As a result, PingER's deployment now covers the real-time monitoring of worldwide Internet performance and, in particular, West and Central Africa for the first time. We report on the results from the ICTP sites and quantitatively identify regions with poor performance, identify trends, discuss experiences and future work. (author)

Monitoring the Digital Divide

International Nuclear Information System (INIS)

Cottrell, Les

2003-01-01

It is increasingly important to support the large numbers of scientists working in remote areas and having low bandwidth access to the Internet. This will continue to be the case for years to come since there is evidence from PingER performance measurements that the, so-called, digital divide is not decreasing. In this work, we review the collaborative work of The Abdus Salam International Center for Theoretical Physics (ICTP) in Trieste, a leading organization promoting science dissemination in the developing world- and SLAC in Stanford, to monitor by PingER, Universities and Research Institutions all over the developing world following the recent ''Recommendations of Trieste'' to help bridge the digital divide. As a result, PingER's deployment now covers the real-time monitoring of worldwide Internet performance and, in particular, West and Central Africa for the first time. We report on the results from the ICTP sites and quantitatively identify regions with poor performance, identify trends, discuss experiences and future work

Digital stories as a tool for health promotion and youth engagement.

Science.gov (United States)

Fletcher, Sarah; Mullett, Jennifer

2016-08-15

To provide opportunities for intergenerational knowledge sharing for healthy lifestyles; to facilitate youth and Elder mentorship; and to increase the self-esteem of youth by celebrating identity, cultural practices and community connection through the creation and sharing of digital stories. A youth research team (8 youth) aged 13-25, youth participants (60 core participants and 170 workshop participants) and Elders (14) from First Nations communities. The project was conducted with participants from several communities on Vancouver Island through on-site workshops and presentations. Youth and Elders were invited to a 3-day digital story workshop consisting of knowledge-sharing sessions by Elders and digital story training by the youth research team. Workshop attendees returned to their communities to develop stories. The group re-convened at the university to create digital stories focused on community connections, family histories and healthy lifestyles. During the following year the research team delivered instructional sessions in communities on the digital story process. The youth involved reported increased pride in community as well as new or enhanced relationships with Elders. The digital stories method facilitated intergenerational interactions and engaged community members in creating a digital representation of healthy lifestyles. The process itself is an intervention, as it affords critical reflection on historical, cultural and spiritual ideas of health and what it means to be healthy in an Aboriginal community. It is a particularly relevant health promotion tool in First Nations communities with strong oral history traditions.

CERN Courier goes digital

CERN Multimedia

Christine Sutton, CERN Courier editor

2013-01-01

The January/February 2013 issue of the CERN Courier offers a new way to access the content – the first digital edition of the magazine.   The CERN Courier dates back to August 1959, when the first issue appeared, consisting of 8 black-and-white pages. Since then it has seen many changes in design and layout, leading to the current full-colour editions of more than 50 pages on average. It went on the web for the first time in October 1998, when IOP Publishing took over the production work. Now, we have taken another step forward with a digital edition that provides yet another means to access the content beyond the web and print editions, which continue as before. To download the digital edition, click here. To sign up to the new issue alert, please visit: http://cerncourier.com/cws/sign-up.

Lessons learned in digital upgrade projects digital control system implementation at US nuclear power stations

International Nuclear Information System (INIS)

Kelley, S.; Bolian, T. W.

2006-01-01

AREVA NP has gained significant experience during the past five years in digital upgrades at operating nuclear power stations in the US. Plants are seeking modernization with digital technology to address obsolescence, spare parts availability, vendor support, increasing age-related failures and diminished reliability. New systems offer improved reliability and functionality, and decreased maintenance requirements. Significant lessons learned have been identified relating to the areas of licensing, equipment qualification, software quality assurance and other topics specific to digital controls. Digital control systems have been installed in non safety-related control applications at many utilities within the last 15 years. There have also been a few replacements of small safety-related systems with digital technology. Digital control systems are proving to be reliable, accurate, and easy to maintain. Digital technology is gaining acceptance and momentum with both utilities and regulatory agencies based upon the successes of these installations. Also, new plants are being designed with integrated digital control systems. To support plant life extension and address obsolescence of critical components, utilities are beginning to install digital technology for primary safety-system replacement. AREVA NP analyzed operating experience and lessons learned from its own digital upgrade projects as well as industry-wide experience to identify key issues that should be considered when implementing digital controls in nuclear power stations

Digital chest radiography

DEFF Research Database (Denmark)

Debess, Jeanne Elisabeth; Johnsen, Karen Kirstine; Thomsen, Henrik

on collimation and dose reduction in digital chest radiography Methods and Materials A retrospective study of digital chest radiography is performed to evaluate the primary x-ray tube collimation of the PA and lateral radiographs. Data from one hundred fifty self-reliant female patients between 15 and 55 years...

Reconceiving pasts in a digital age

OpenAIRE

Tanaka, Stefan

2016-01-01

This essay explores the way that digital media helps us think differently about how we practice history. Digital media can raise two issues about how our current practices can offer new ways to explore the current state of historiography. First, the more one is immersed in digital tools, they make us question first principles, the various practices and assumptions of modern history itself. Second, it offers ways of communicating the past that do not hide the process of “doing” history. In thi...

Constraints on models with a break in the primordial power spectrum

Energy Technology Data Exchange (ETDEWEB)

Li Hong, E-mail: hongli@mail.ihep.ac.c [Institute of High Energy Physics, Chinese Academy of Science, P.O. Box 918-4, Beijing 100049 (China); Theoretical Physics Center for Science Facilities (TPCSF), Chinese Academy of Science (China); Kavli Institute for Theoretical Physics, Chinese Academy of Science, Beijing 100190 (China); Xia Junqing [Scuola Internazionale Superiore di Studi Avanzati, Via Bonomea 265, I-34136 Trieste (Italy); Brandenberger, Robert [Department of Physics, McGill University, 3600 University Street, Montreal, QC, H3A 2T8 (Canada); Institute of High Energy Physics, Chinese Academy of Science, P.O. Box 918-4, Beijing 100049 (China); Theoretical Physics Center for Science Facilities (TPCSF), Chinese Academy of Science (China); Kavli Institute for Theoretical Physics, Chinese Academy of Science, Beijing 100190 (China); Zhang Xinmin [Institute of High Energy Physics, Chinese Academy of Science, P.O. Box 918-4, Beijing 100049 (China); Theoretical Physics Center for Science Facilities (TPCSF), Chinese Academy of Science (China)

2010-07-05

One of the characteristics of the 'Matter Bounce' scenario, an alternative to cosmological inflation for producing a scale-invariant spectrum of primordial adiabatic fluctuations on large scales, is a break in the power spectrum at a characteristic scale, below which the spectral index changes from n{sub s}=1 to n{sub s}=3. We study the constraints which current cosmological data place on the location of such a break, and more generally on the position of the break and the slope at length scales smaller than the break. The observational data we use include the WMAP five-year data set (WMAP5), other CMB data from BOOMERanG, CBI, VSA, and ACBAR, large-scale structure data from the Sloan Digital Sky Survey (SDSS, their luminous red galaxies sample), Type Ia Supernovae data (the 'Union' compilation), and the Sloan Digital Sky Survey Lyman-{alpha} forest power spectrum (Ly{alpha}) data. We employ the Markov Chain Monte Carlo method to constrain the features in the primordial power spectrum which are motivated by the matter bounce model. We give an upper limit on the length scale where the break in the spectrum occurs.

Constraints on models with a break in the primordial power spectrum

International Nuclear Information System (INIS)

Li Hong; Xia Junqing; Brandenberger, Robert; Zhang Xinmin

2010-01-01

One of the characteristics of the 'Matter Bounce' scenario, an alternative to cosmological inflation for producing a scale-invariant spectrum of primordial adiabatic fluctuations on large scales, is a break in the power spectrum at a characteristic scale, below which the spectral index changes from n s =1 to n s =3. We study the constraints which current cosmological data place on the location of such a break, and more generally on the position of the break and the slope at length scales smaller than the break. The observational data we use include the WMAP five-year data set (WMAP5), other CMB data from BOOMERanG, CBI, VSA, and ACBAR, large-scale structure data from the Sloan Digital Sky Survey (SDSS, their luminous red galaxies sample), Type Ia Supernovae data (the 'Union' compilation), and the Sloan Digital Sky Survey Lyman-α forest power spectrum (Lyα) data. We employ the Markov Chain Monte Carlo method to constrain the features in the primordial power spectrum which are motivated by the matter bounce model. We give an upper limit on the length scale where the break in the spectrum occurs.

Digital Living at Home

DEFF Research Database (Denmark)

Andersen, Pernille Viktoria Kathja; Christiansen, Ellen Tove

2013-01-01

of these user voices has directed us towards a ‘home-keeping’ design discourse, which opens new horizons for design of digital home control systems by allowing users to perform as self-determined controllers and groomers of their habitat. The paper concludes by outlining the implications of a ‘home......Does living with digital technology inevitably lead to digital living? Users talking about a digital home control system, they have had in their homes for eight years, indicate that there is more to living with digital technology than a functional-operational grip on regulation. Our analysis......-keeping’ design discourse....

Digit Sucking Habit and Association with Dental Caries and Oral Hygiene Status of Children Aged 6 Months to 12 Years Resident in Semi-Urban Nigeria.

Science.gov (United States)

Kolawole, Kikelomo Adebanke; Folayan, Morenike Oluwatoyin; Agbaje, Hakeem Olatunde; Oyedele, Titus Ayodeji; Oziegbe, Elizabeth Obhioneh; Onyejaka, Nneka Kate; Chukwumah, Nneka Maureen; Oshomoji, Olusegun Victor

2016-01-01

Non-nutritive sucking (NNS) is a common behavior in childhood. The association between digit sucking, dental caries and oral health has been studied with inconclusive results. The objectives of this study were to determine the prevalence of, and the association between digit sucking, caries and oral hygiene status of children age six months to 12 years, resident in Ile-Ife, Osun State, Nigeria. A cross-sectional study was conducted in Ife Central Local Government Area of Osun State. Data were collected through a household survey using a multi-stage sampling procedure from children between six months and 12 years. Details of each child's socio-demographic characteristics, digit sucking habits, caries status and oral health status were collected. The association between digit sucking, caries status and oral hygiene status was determined using Chi square and Logistic regression. The mean age of the 992 study participants was 5.8 ± (3.2) years. The prevalence of digit sucking, caries and poor oral hygiene were 7.2%, 10.5% and 2.4% respectively. The mean dmft score was 0.22 ± (0.80), mean DMFT score was 0.04 ± (0.30) while mean Oral Hygiene Index score was 1.27 ± (0.73). Digit sucking increased the odds of having caries (OR: 1.28; CI: 0.58-2.81) but decreased the odds of having poor oral hygiene (OR: 0.58; CI: 0.34-1.01) insignificantly. Digit sucking was not a significant predictor of caries and oral hygiene status, although the odds of having caries increased while the odds of having poor oral hygiene decreased with digit sucking.

The distributed development environment for SDSS software

International Nuclear Information System (INIS)

Berman, E.; Gurbani, V.; Mackinnon, B.; Newberg, H. Nicinski, T.; Petravick, D.; Pordes, R.; Sergey, G.; Stoughton, C.; Lupton, R.

1994-04-01

The authors present an integrated science software development environment, code maintenance and support system for the Sloan Digital Sky Survey (SDSS) now being actively used throughout the collaboration

First-Year College Students' Strengths Awareness and Perceived Leadership Development

Science.gov (United States)

Soria, Krista M.; Roberts, Julia E.; Reinhard, Alex P.

2015-01-01

The purpose of this study was to examine whether first-year college students' strengths awareness is associated with their perceived leadership development. The institution in this study offered all first-year students the Clifton StrengthsFinder assessment and strengths-related programming. The results of hierarchical regression analysis of two…

Fully Digital Chaotic Differential Equation-based Systems And Methods

KAUST Repository

Radwan, Ahmed Gomaa Ahmed; Zidan, Mohammed A.; Salama, Khaled N.

2012-01-01

Various embodiments are provided for fully digital chaotic differential equation-based systems and methods. In one embodiment, among others, a digital circuit includes digital state registers and one or more digital logic modules configured to obtain a first value from two or more of the digital state registers; determine a second value based upon the obtained first values and a chaotic differential equation; and provide the second value to set a state of one of the plurality of digital state registers. In another embodiment, a digital circuit includes digital state registers, digital logic modules configured to obtain outputs from a subset of the digital shift registers and to provide the input based upon a chaotic differential equation for setting a state of at least one of the subset of digital shift registers, and a digital clock configured to provide a clock signal for operating the digital shift registers.

Fully Digital Chaotic Differential Equation-based Systems And Methods

KAUST Repository

Radwan, Ahmed Gomaa Ahmed

2012-09-06

Various embodiments are provided for fully digital chaotic differential equation-based systems and methods. In one embodiment, among others, a digital circuit includes digital state registers and one or more digital logic modules configured to obtain a first value from two or more of the digital state registers; determine a second value based upon the obtained first values and a chaotic differential equation; and provide the second value to set a state of one of the plurality of digital state registers. In another embodiment, a digital circuit includes digital state registers, digital logic modules configured to obtain outputs from a subset of the digital shift registers and to provide the input based upon a chaotic differential equation for setting a state of at least one of the subset of digital shift registers, and a digital clock configured to provide a clock signal for operating the digital shift registers.

Vectors of Identity Development during the First Year: Black First-Generation Students' Reflections

Science.gov (United States)

Liversage, Lindi; Naudé, Luzelle; Botha, Anja

2018-01-01

In this study, black South African first-generation students' experiences related to identity development during their first year at a higher education institution were explored. Chickering and Reisser's [1993. "Education and Identity." 2nd ed. San Francisco, CA: Jossey-Bass] seven-vector identity development theory served as overarching…

Effectiveness of Feedback in First Year Physics

DEFF Research Database (Denmark)

Bearden, Ian; Voigt, Karen A; Mathiasen, Helle

How can we provide better and more effective feedback to our students? How can we encourage students to use feedback effectively? We will present results of a study of first year physics students addressing these questions and comparing the effectiveness of written and screencast feedback....

Digital literacy and safety skills

NARCIS (Netherlands)

Sonck, N.; Livingstone, S.; Kuiper, E.; de Haan, J.

2011-01-01

Children’s digital skills were assessed by asking 25,000 European 9-16 year old internet users about their online activities, skills and self-efficacy. The range of digital skills and online activities are linked. But many younger (11-13 year old) children lack key critical and safety skills. Also,

VizieR Online Data Catalog: Compact steep spectrum new sample (Kunert-Bajraszewska+, 2010)

Science.gov (United States)

Kunert-Bajraszewska, M.; Gawronski, M. P.; Labiano, A.; Siemiginowska, A.

2013-08-01

Using the final release of FIRST, combined with the Green Bank 6-cm (GB6) survey at 4.85GHz, we looked for unresolved, isolated sources, that is, more compact than the FIRST beam (5.4-arcsec), and surrounded by an empty field (we adopted 1-arcmin as the radius of that field). We required that the redshifts of the objects identified with radio sources were known, and we extracted these from the National Aeronautics and Space Administration (NASA)/Infrared Processing and Analysis Center (IPAC) Extragalactic Data base (NED) and the Sloan Digital Sky Survey (SDSS). (3 data files).

First Year Engagement & Retention: A Goal-Setting Approach

Science.gov (United States)

Tuffley, David; Antonio, Amy

2013-01-01

First year students face a daunting range of challenges as they make the transition to university life. Their experiences in the first months of university have a defining influence on their success or otherwise in their studies. The purpose of this paper is to report on the results of a case study that tests the efficacy of a student engagement…

Countdown to zero Day stuxnet and the launch of the world's first digital weapon

CERN Document Server

Zetter, Kim

2014-01-01

In January 2010, inspectors with the International Atomic Energy Agency noticed that centrifuges at an Iranian uranium enrichment plant were failing at an unprecedented rate. The cause was a complete mystery—apparently as much to the technicians replacing the centrifuges as to the inspectors observing them. Then, five months later, a seemingly unrelated event occurred: A computer security firm in Belarus was called in to troubleshoot some computers in Iran that were crashing and rebooting repeatedly. At first, the firm’s programmers believed the malicious code on the machines was a simple, routine piece of malware. But as they and other experts around the world investigated, they discovered a mysterious virus of unparalleled complexity. They had, they soon learned, stumbled upon the world’s first digital weapon. For Stuxnet, as it came to be known, was unlike any other virus or worm built before: Rather than simply hijacking targeted computers or stealing information from them, it escaped the d...

Digital front-end module (DFEM) series; Digital front end module (DFEM) series

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

The digital front-end module (DFEM) is a module in which the processes ranging from the reception of digitally modulated radiofrequencies to the output of digital IF (Intermediate Frequency) signals or data streams are integrated. Beginning with a module for the MCNS (Multimedia Cable Network System) cable modem which was the first module in this business field approved by the Cable Labs, U.S., Toshiba has developed a series of DFEMs for various digital media for satellites, ground waves, and CATV (Cable Television) systems. The series is characterized by (1) the serialization of DFEMs compatible with various digital modulation techniques such as 8 PSK (Phase Shift Keying), OFDM (Orthogonal Frequency Division Multiplexing), and 256 QAM (Quadrature Amplitude Modulation), (2) easy connection with digital circuits thanks to the high shielding effect, and (3) the achievement of smaller size, higher performance, and lower power consumption. (translated by NEDO)

First-Year Seminar (FYS)--The Advantages That This Course Offers

Science.gov (United States)

Jaijairam, Paul

2016-01-01

First-Year Seminar (FYS) is an introductory class offered to first-year students to help them acclimate to the college environment, develop effective strategies for studying, and learn techniques that will allow them to swiftly complete small assignments and sizable research projects. In 2014, approximately 80 percent of universities offered FYS,…

Accessing powerful knowledge: a comparative study of two first year ...

African Journals Online (AJOL)

This paper presents a case study of two first year sociology courses run at an elite South African university in order to speak to student perspectives on the sociology curriculum. The paper provides a comparative analysis of the academic experiences of extended degree (ED) students registered on two first year courses, ...

Intensity-Modulated Radiotherapy in the Treatment of Oropharyngeal Cancer: An Update of the Memorial Sloan-Kettering Cancer Center Experience

International Nuclear Information System (INIS)

Setton, Jeremy; Caria, Nicola; Romanyshyn, Jonathan; Koutcher, Lawrence; Wolden, Suzanne L.; Zelefsky, Michael J.; Rowan, Nicholas; Sherman, Eric J.; Fury, Matthew G.; Pfister, David G.; Wong, Richard J.; Shah, Jatin P.; Kraus, Dennis H.; Shi Weiji; Zhang Zhigang; Schupak, Karen D.; Gelblum, Daphna Y.; Rao, Shyam D.; Lee, Nancy Y.

2012-01-01

Purpose: To update the Memorial Sloan-Kettering Cancer Center’s experience with intensity-modulated radiotherapy (IMRT) in the treatment of oropharyngeal cancer (OPC). Methods and Materials: Between September 1998 and April 2009, 442 patients with histologically confirmed OPC underwent IMRT at our center. There were 379 men and 63 women with a median age of 57 years (range, 27–91). The disease was Stage I in 2%, Stage II in 4%, Stage III in 21%, and Stage IV in 73% of patients. The primary tumor subsite was tonsil in 50%, base of tongue in 46%, pharyngeal wall in 3%, and soft palate in 2%. The median prescription dose to the planning target volume of the gross tumor was 70 Gy for definitive (n = 412) cases and 66 Gy for postoperative cases (n = 30). A total 404 patients (91%) received chemotherapy, including 389 (88%) who received concurrent chemotherapy, the majority of which was platinum-based. Results: Median follow-up among surviving patients was 36.8 months (range, 3–135). The 3-year cumulative incidence of local failure, regional failure, and distant metastasis was 5.4%, 5.6%, and 12.5%, respectively. The 3-year OS rate was 84.9%. The incidence of late dysphagia and late xerostomia ≥Grade 2 was 11% and 29%, respectively. Conclusions: Our results confirm the feasibility of IMRT in achieving excellent locoregional control and low rates of xerostomia. According to our knowledge, this study is the largest report of patients treated with IMRT for OPC.

Intensity-Modulated Radiotherapy in the Treatment of Oropharyngeal Cancer: An Update of the Memorial Sloan-Kettering Cancer Center Experience

Energy Technology Data Exchange (ETDEWEB)

Setton, Jeremy; Caria, Nicola; Romanyshyn, Jonathan; Koutcher, Lawrence; Wolden, Suzanne L.; Zelefsky, Michael J.; Rowan, Nicholas [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Sherman, Eric J.; Fury, Matthew G.; Pfister, David G. [Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Wong, Richard J.; Shah, Jatin P.; Kraus, Dennis H. [Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Shi Weiji; Zhang Zhigang [Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Schupak, Karen D.; Gelblum, Daphna Y.; Rao, Shyam D. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Lee, Nancy Y., E-mail: Leen2@mskcc.org [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States)

2012-01-01

Purpose: To update the Memorial Sloan-Kettering Cancer Center's experience with intensity-modulated radiotherapy (IMRT) in the treatment of oropharyngeal cancer (OPC). Methods and Materials: Between September 1998 and April 2009, 442 patients with histologically confirmed OPC underwent IMRT at our center. There were 379 men and 63 women with a median age of 57 years (range, 27-91). The disease was Stage I in 2%, Stage II in 4%, Stage III in 21%, and Stage IV in 73% of patients. The primary tumor subsite was tonsil in 50%, base of tongue in 46%, pharyngeal wall in 3%, and soft palate in 2%. The median prescription dose to the planning target volume of the gross tumor was 70 Gy for definitive (n = 412) cases and 66 Gy for postoperative cases (n = 30). A total 404 patients (91%) received chemotherapy, including 389 (88%) who received concurrent chemotherapy, the majority of which was platinum-based. Results: Median follow-up among surviving patients was 36.8 months (range, 3-135). The 3-year cumulative incidence of local failure, regional failure, and distant metastasis was 5.4%, 5.6%, and 12.5%, respectively. The 3-year OS rate was 84.9%. The incidence of late dysphagia and late xerostomia {>=}Grade 2 was 11% and 29%, respectively. Conclusions: Our results confirm the feasibility of IMRT in achieving excellent locoregional control and low rates of xerostomia. According to our knowledge, this study is the largest report of patients treated with IMRT for OPC.

Developing Effective Guidelines for Faculty Teaching First-Year University Students

Science.gov (United States)

Carter, Irene; Leslie, Donald; Moore, Sarah

2010-01-01

First-year university students are a diverse group of individuals with various abilities and needs. Failure of the university and its teaching faculty to meet the needs of first-year students may result in abandonment of the pursuit of a degree. This project informs instructors about the practices that strengthen a learning-centred approach and…

DIGITAL MARKETING: SUCCESS METRICS, FUTURE TRENDS

OpenAIRE

Preeti Kaushik

2017-01-01

Abstract – Business Marketing is one of the prospective which has been tremendously affected by digital world in last few years. Digital marketing refers to doing advertising through digital channels. This paper provides detailed study of metrics to measure success of digital marketing platform and glimpse of future of technologies by 2020.

Virology: The Next Generation from Digital PCR to Single Virion Genomics

Energy Technology Data Exchange (ETDEWEB)

White, Richard A.; Brazelton De Cardenas, Jessica N.; Hayden, Randall T.

2015-10-01

In the past 25 years, virology has had major technology breakthroughs stemming first from the introduction of nucleic acid amplification testing, but more recently from the use of next-generation sequencing, digital PCR, and the possibility of single virion genomics. These technologies have and will improve diagnosis and disease state monitoring in clinical settings, aid in environmental monitoring, and reveal the vast genetic potential of viruses. Using the principle of limiting dilution, digital PCR amplifies single molecules of DNA in highly partitioned endpoint reactions and reads each of those reactions as either positive or negative based on the presence or absence of target fluorophore. In this review, digital PCR will be highlighted along with current studies, advantages/disadvantages, and future perspectives with regard to digital PCR, viral load testing, and the possibility of single virion genomics.

Milwaukee Parental Choice Program. First Year Report.

Science.gov (United States)

Witte, John F.

A preliminary evaluation and report were conducted of the Milwaukee (Wisconsin) Public Schools' (MPS) Parental Choice Program (PCP) following its first year of operation. The state legislated program provides an opportunity for students meeting specific criteria to attend private, non-sectarian schools in Milwaukee. A payment from public funds…

First Fifty Years of Chemoresistive Gas Sensors

Directory of Open Access Journals (Sweden)

Giovanni Neri

2015-01-01

Full Text Available The first fifty years of chemoresistive sensors for gas detection are here reviewed, focusing on the main scientific and technological innovations that have occurred in the field over the course of these years. A look at advances made in fundamental and applied research and leading to the development of actual high performance chemoresistive devices is presented. The approaches devoted to the synthesis of novel semiconducting materials with unprecedented nanostructure and gas-sensing properties have been also presented. Perspectives on new technologies and future applications of chemoresistive gas sensors have also been highlighted.

Mining the Sloan digital sky survey in search of extremely α-poor stars in the galaxy

Energy Technology Data Exchange (ETDEWEB)

Xing, Q. F.; Zhao, G., E-mail: qfxing@nao.cas.cn, E-mail: gzhao@nao.cas.cn [Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

2014-07-20

As we know, the majority of metal-poor Galactic halo stars appear to have chemical abundances that were enhanced by α-elements (e.g., O, Mg, Si, Ca, and Ti) during the early stage of the Galaxy. Observed metal-poor halo stars preserved this pattern by exhibiting abundance ratios [α/Fe] ∼+0.4. A few striking exceptions that show severe departures from the general enhanced α-element chemical abundance trends of the halo have been discovered in recent years. They possess relatively low [α/Fe] compared to other comparable-metallicity stars, with abundance ratios over 0.5 dex lower. These stars may have a different chemical enrichment history from the majority of the halo. Similarly, low-α abundances are also displayed by satellite dwarf spheroidal (dSph) galaxies. We present a method to select extremely α-poor (EAP) stars from the SDSS/SEGUE survey. The method consists of a two-step approach. In the first step, we select suspected metal-poor ([Fe/H] <–0.5) and α-poor ([Mg/Fe] <0) stars as our targets. In the second step, we determine [Mg/Fe] from low-resolution (R = 2000) stellar spectra for our targets and select stars with [Mg/Fe] <–0.1 as candidate EAP stars. In a sample of 40,000 stars with atmospheric parameters in the range of T{sub eff} = [4500, 7000] K, log g = [1.0, 5.0], and [Fe/H] = [–4.0, +0.5], 14 candidate stars were identified. Three of these stars are found to have already been confirmed by other research.

Digital gaming expertise

DEFF Research Database (Denmark)

Toft-Nielsen, Claus

In a digitally saturated environment digital media users of all kinds, engaged in different areas of activity, are increasingly categorized in terms of their ability to appropriate and use digital media – they are regarded as non-users, experts, natives, or literates for instance. Within communic......In a digitally saturated environment digital media users of all kinds, engaged in different areas of activity, are increasingly categorized in terms of their ability to appropriate and use digital media – they are regarded as non-users, experts, natives, or literates for instance. Within...... communication and game studies there are multiple understandings of how digital expertise is expressed and performed, and subsequently how these expressions and performances can be valued, understood and theorized within the research community. Among other things expertise with and within digital games has......-of-game (Schrøder, 2003) in a three-year-long study of men and women (couples and singles) playing the largest Massively Multiplayer Online Role-Playing Game to date, World of Warcraft. In focusing on how different aspects of gaming expertise are articulated, negotiated, and performed, I aim to illustrate how...

Peer to peer mentoring: Outcomes of third-year midwifery students mentoring first-year students.

Science.gov (United States)

Hogan, Rosemarie; Fox, Deborah; Barratt-See, Georgina

2017-06-01

Undergraduate midwifery students commonly experience anxiety in relation to their first clinical placement. A peer mentoring program for midwifery students was implemented in an urban Australian university. The participants were first-year mentee and third-year mentor students studying a three-year Bachelor degree in midwifery. The program offered peer support to first-year midwifery students who had little or no previous exposure to hospital clinical settings. Mentors received the opportunity to develop mentoring and leadership skills. The aim was to explore the benefits, if any, of a peer mentoring program for midwifery students. The peer mentoring program was implemented in 2012. Sixty-three peer mentors and 170 mentees participated over three academic years. Surveys were distributed at the end of each academic year. Quantitative survey data were analysed descriptively and qualitative survey data were analysed thematically using NVivo 10 software. Over 80% of mentors and mentees felt that the program helped mentees adjust to their midwifery clinical placement. At least 75% of mentors benefited, in developing their communication, mentoring and leadership skills. Three themes emerged from the qualitative data, including 'Receiving start-up advice'; 'Knowing she was there' and 'Wanting more face to face time'. There is a paucity of literature on midwifery student peer mentoring. The findings of this program demonstrate the value of peer support for mentees and adds knowledge about the mentor experience for undergraduate midwifery students. The peer mentor program was of benefit to the majority of midwifery students. Copyright © 2017 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.

The Digital Scientist to be launched in the New Year

CERN Multimedia

The Digital Scientist Team

2010-01-01

If you've been on a stroll through Restaurant No. 1 or walked through the corridors of Building 600, a colourful poster - with spotlights, a QR code and the words “Coming soon...” - might have caught your attention. This has been brought to you by the team at iSGTW (International Science Grid This Week), the CERN-based grid computing newsletter, and signifies that the publication is being transformed... into The Digital Scientist.   Image courtesy of Andre-Pierre Olivier from e-ScienceTalk. iSGTW has been successfully contributing to the international grid community and steadily growing in popularity and appeal, as shown by a readership drawn from nearly 200 countries that increased by 89% in under two and a half years. Now, the goal is to expand the coverage of the publication to include high-end technologies such as supercomputing, volunteer computing, distributed computing, networks and cloud computing, as well as grid computing. This change in the publication brings with ...

Gamification to Improve First Year Engagement

OpenAIRE

Colleran, John; Lloyd McKernan, Aoife; Naughton, Julie Ann; Vaughan, Brian

2016-01-01

The purpose of this project was to examine the role of Gamification in increasing first year student engagement within the third level educational setting. A literature review was carried out in order to explore the teaching philosophy behind gamification in education and review the quantitative and qualitative evidence regarding its use. Gamification can be broadly described as the application of gaming methods and elements in non-gaming contexts in order to improve user engagement and user ...

Antiretroviral changes during the first year of therapy

Directory of Open Access Journals (Sweden)

Antonio Carlos Policarpo Carmo Sá Bandeira

Full Text Available Summary Introduction: The Brazilian HIV/AIDS management and treatment guideline (PCDT, published in 2013, recommends and standardizes the use of highly active antiretroviral therapy (HAART in all adult patients, in spite of LTCD4 count. This study aimed to analyze the first year of HAART use in patients from a reference center on HIV/AIDS management in Fortaleza, Ceará. Method: This descriptive study reviewed all prescription forms of antiretroviral regimens initiation and changes from January to July 2014. All antiretroviral regimen changes that occurred during the first year of therapy were evaluated. Data were analyzed with SPSS version 20. Mean, standard deviation and frequency, Student’s t and Mann-Whitney tests calculations were used, with significance at p<0.05. Results: From 527 patients initiating HAART, 16.5% (n=87 had a regimen change in the first year. These patients were mostly male (59.8%; n=52, aged 20 to 39 years, with only one HAART change (72.4%; n=63. Efavirenz was the most often changed drug, followed by tenofovir, zidovudine and lopinavir/ritonavir. Mean time of HAART changes was 120 days, with adverse reactions as the most prevalent cause. HAART was effective in decreasing viral load since second month of treatment (p=0.003 and increasing LTCD4 lymphocytes since fifth month (p<0.001. Conclusion: The main cause of initial HAART changes was adverse reaction and most patients had only one change in the HAART regimen. HAART prescription was in accordance to the PCDT from 2013.

Review of Digital Research in the Study of Classical Antiquity [Book

Directory of Open Access Journals (Sweden)

Adam Rabinowitz

2011-07-01

Full Text Available It is often stated that trying to deal with information on the internet is like drinking from a firehose. But trying to put together a book about the current state of digital anything must be rather more like trying to paint a landscape from the window of a moving train. By the time the painting is complete, the scenery has changed dramatically. This puts books on digital approaches to academic disciplines in an interesting position: by the time a volume makes it into the hands of its readers, it is already a historical document as well as a scholarly work. The editors of Digital Research in the Study of Classical Antiquity are very aware of this: as they state, the book seeks "to create a snapshot of the research activities of Digital Classicist members as represented by a selection of the papers given at our Summer seminars and conference panels in one particular year, 2007" (p10. When one considers that the printed volume went to press in 2010, and is being reviewed in 2011, this means that almost four years—a digital eternity—have passed since most of the papers were first composed. I think, therefore, it will be most useful to discuss Digital Research from two perspectives: first, in terms of its scholarly contribution, and second, in terms of what the framing of this work and the identity of its contributors tell us about a particular moment in the history of the field of 'digital humanities'.

Financial Aid and First-Year Collegiate GPA: A Regression Discontinuity Approach

Science.gov (United States)

Curs, Bradley R.; Harper, Casandra E.

2012-01-01

Using a regression discontinuity design, we investigate whether a merit-based financial aid program has a causal effect on the first-year grade point average of first-time out-of-state freshmen at the University of Oregon. Our results indicate that merit-based financial aid has a positive and significant effect on first-year collegiate grade point…

Digital Literacy: A Palestinian Refugee Perspective

Science.gov (United States)

Traxler, John

2018-01-01

This paper is the first attempt to explore digital literacy in the specific context of the Palestinian refugee community in the Middle East by looking at the cultural specificity of digital literacy theorising and practice, by analysing current digital education policy in the countries hosting the Palestinian refugee community and by documenting…

Opportunity to Learn First Year Mathematics in Teacher Training ...

African Journals Online (AJOL)

kofimereku

first year teacher training mathematics syllabus were not taught by the end of the year and which ones .... training college in Kommenda, Central Region as a pilot study. The responses ..... calls for efforts to give more attention to these groups.

Predicting first-year achievement by pedagogy and skill development in the first weeks at university

NARCIS (Netherlands)

Torenbeek, M.; Jansen, E. P. W. A.; Hofman, W. H. A.

2011-01-01

Central in this study is the relationship between the pedagogical approach and generic skill development in the first 10 weeks at university, students' perception of the fit between secondary and university education and first-year achievement. Information regarding the pedagogical approach and

Digital cardiovascular imaging

International Nuclear Information System (INIS)

Myerowitz, P.D.; Mistretta, C.A.; Shaw, C.-G.; Van Lysel, M.S.; Swanson, D.K.; Lasser, T.A.; Dhanani, S.P.; Zarnstorff, W.C.; Vander Ark, C.R.; Dobbins, J.T.; Peppler, W.W.; Crummy, A.B.

1982-01-01

The authors have previously reported on real time digital fluoroscopic subtraction techniques developed in the laboratory during the past 10 years. This paper outlines basic apparatus configuration and imaging modes used for preliminary studies involving visualization of the canine and human heart. All of the techniques involve the use of real time digital subtraction processing of data from an image intensified television fluoroscopy system. Based on the configuration of the digital processing equipment a number of different imaging modalities are possible. A brief description of the apparatus and these imaging modes is given. (Auth.)

Theory of Digital Automata

CERN Document Server

Borowik, Bohdan; Lahno, Valery; Petrov, Oleksandr

2013-01-01

This book serves a dual purpose: firstly to combine the treatment of circuits and digital electronics, and secondly, to establish a strong connection with the contemporary world of digital systems. The need for this approach arises from the observation that introducing digital electronics through a course in traditional circuit analysis is fast becoming obsolete. Our world has gone digital. Automata theory helps with the design of digital circuits such as parts of computers, telephone systems and control systems. A complete perspective is emphasized, because even the most elegant computer architecture will not function without adequate supporting circuits. The focus is on explaining the real-world implementation of complete digital systems. In doing so, the reader is prepared to immediately begin design and implementation work. This work serves as a bridge to take readers from the theoretical world to the everyday design world where solutions must be complete to be successful.

Field-Deployable Acoustic Digital Systems for Noise Measurement

Science.gov (United States)

Shams, Qamar A.; Wright, Kenneth D.; Lunsford, Charles B.; Smith, Charlie D.

2000-01-01

Langley Research Center (LaRC) has for years been a leader in field acoustic array measurement technique. Two field-deployable digital measurement systems have been developed to support acoustic research programs at LaRC. For several years, LaRC has used the Digital Acoustic Measurement System (DAMS) for measuring the acoustic noise levels from rotorcraft and tiltrotor aircraft. Recently, a second system called Remote Acquisition and Storage System (RASS) was developed and deployed for the first time in the field along with DAMS system for the Community Noise Flight Test using the NASA LaRC-757 aircraft during April, 2000. The test was performed at Airborne Airport in Wilmington, OH to validate predicted noise reduction benefits from alternative operational procedures. The test matrix was composed of various combinations of altitude, cutback power, and aircraft weight. The DAMS digitizes the acoustic inputs at the microphone site and can be located up to 2000 feet from the van which houses the acquisition, storage and analysis equipment. Digitized data from up to 10 microphones is recorded on a Jaz disk and is analyzed post-test by microcomputer system. The RASS digitizes and stores acoustic inputs at the microphone site that can be located up to three miles from the base station and can compose a 3 mile by 3 mile array of microphones. 16-bit digitized data from the microphones is stored on removable Jaz disk and is transferred through a high speed array to a very large high speed permanent storage device. Up to 30 microphones can be utilized in the array. System control and monitoring is accomplished via Radio Frequency (RF) link. This paper will present a detailed description of both systems, along with acoustic data analysis from both systems.

Digital Storytelling for Enhancing Student Academic Achievement, Critical Thinking, and Learning Motivation: A Year-Long Experimental Study

Science.gov (United States)

Yang, Ya-Ting C.; Wu, Wan-Chi I.

2012-01-01

The purpose of this study was to explore the impact of Digital storytelling (DST) on the academic achievement, critical thinking, and learning motivation of senior high school students learning English as a foreign language. The one-year study adopted a pretest and posttest quasi-experimental design involving 110 10th grade students in two English…

Digital design and computer architecture

CERN Document Server

Harris, David

2010-01-01

Digital Design and Computer Architecture is designed for courses that combine digital logic design with computer organization/architecture or that teach these subjects as a two-course sequence. Digital Design and Computer Architecture begins with a modern approach by rigorously covering the fundamentals of digital logic design and then introducing Hardware Description Languages (HDLs). Featuring examples of the two most widely-used HDLs, VHDL and Verilog, the first half of the text prepares the reader for what follows in the second: the design of a MIPS Processor. By the end of D

Low-dose biplanar skeletal survey versus digital skeletal survey in multiple myeloma

International Nuclear Information System (INIS)

Boutry, Nathalie; Dutouquet, Bastien; Cotten, Anne; Leleu, Xavier; Vieillard, Marie-Helene; Duhamel, Alain

2013-01-01

To evaluate the low-dose biplanar (LDB) skeletal survey (SS) for the assessment of focal bone involvement in patients with multiple myeloma (MM) as compared with digital SS and to compare the two techniques in terms of image quality, patient comfort and radiation exposure. Fifty-six consecutive patients with newly diagnosed or first relapsed MM underwent LDB and digital SS on the same day. These were assessed by two radiologists for the detection of focal bone lesions. In the case of discordance, whole-body MR imaging was performed. Image quality, patient comfort and radiation dose were also assessed. Fifty-six patients (M:30, F:26, mean age, 62 years) with newly diagnosed (n = 21) or first relapse MM (n = 35) were enrolled. A total of 473 bone lesions in 46 patients (82 %) were detected. Out of that total, digital SS detected significantly more lesions than LDB SS (451 [95.35 %] versus 467 [98.73 %]), especially in osteopenic and obese patients. Overall patient satisfaction was greater with LDB SS (48.6 %) compared with digital SS (2.7 %). The radiation dose was significantly reduced (by a factor of 7.8) with the LDB X-ray device. Low-dose biplanar skeletal surveys cannot replace digital SS in all patients suffering from multiple myeloma. (orig.)

Low-dose biplanar skeletal survey versus digital skeletal survey in multiple myeloma

Energy Technology Data Exchange (ETDEWEB)

Boutry, Nathalie [University Hospital of Jeanne de Flandre and University of Lille 2, Departments of Pediatric and Musculoskeletal Imaging, Lille (France); University Hospital of Jeanne de Flandre and University of Lille 2, Department of Pediatric Imaging, Lille (France); Hopital Jeanne de Flandre, Service de Radiopediatrie, Lille (France); Dutouquet, Bastien; Cotten, Anne [University Hospital of Roger Salengro and University of Lille 2, Department of Musculoskeletal Imaging, Lille (France); Leleu, Xavier [University Hospital of Claude Huriez and University of Lille 2, Clinical Hematology Department, Lille (France); Vieillard, Marie-Helene [University Hospital of Roger Salengro and University of Lille 2, Rheumatology Department, Lille (France); Duhamel, Alain [University of Lille 2, Department of Medical Statistics, Lille (France)

2013-08-15

To evaluate the low-dose biplanar (LDB) skeletal survey (SS) for the assessment of focal bone involvement in patients with multiple myeloma (MM) as compared with digital SS and to compare the two techniques in terms of image quality, patient comfort and radiation exposure. Fifty-six consecutive patients with newly diagnosed or first relapsed MM underwent LDB and digital SS on the same day. These were assessed by two radiologists for the detection of focal bone lesions. In the case of discordance, whole-body MR imaging was performed. Image quality, patient comfort and radiation dose were also assessed. Fifty-six patients (M:30, F:26, mean age, 62 years) with newly diagnosed (n = 21) or first relapse MM (n = 35) were enrolled. A total of 473 bone lesions in 46 patients (82 %) were detected. Out of that total, digital SS detected significantly more lesions than LDB SS (451 [95.35 %] versus 467 [98.73 %]), especially in osteopenic and obese patients. Overall patient satisfaction was greater with LDB SS (48.6 %) compared with digital SS (2.7 %). The radiation dose was significantly reduced (by a factor of 7.8) with the LDB X-ray device. Low-dose biplanar skeletal surveys cannot replace digital SS in all patients suffering from multiple myeloma. (orig.)

Cardiovascular Risk Factors among First Year Medical Students

Directory of Open Access Journals (Sweden)

Raj Krishna Dangol

2017-12-01

Full Text Available Introduction: Detection of cardiovascular risk in young age is important to motivate them to modify life styles and seek health care early to lower the chances of acquiring cardiovascular disease in later age. This study was done to assess cardiovascular risk factors among first year medical students. Methods: A cross-sectional study was conducted throughout September and October 2017 in which all first year medical students from a medical college were assessed for the presence of cardiovascular risk factors. Participants’ demography, family history of illness, anthropometric measurements, and blood reports of lipid profile and fasting glucose were acquired. Data were analyzed with Statistical Package for Social Sciences (SPSS-21. Result: There were 99 participants; 55 males and 44 females. One or more risk factors were present in 87 (87.9% participants. Moreover, 67.7% (n = 67 participants had more than one risk factors. Low HDL-cholesterol was the most common (n = 55, 55.6% risk factor followed by elevated triacylglycerol (n = 47, 47.5% and family history of hypertension (n = 45, 45.5%. There was no significant difference in presence of various risk factors between genders. Conclusion: There was higher prevalence of cardiovascular risk factors among first year medical students. Majority of them had more than one risk factors. Low HDL-cholesterol was the most common risk factor. The risk factors were comparable in males and females.

Towards a taxonomy of digital work

OpenAIRE

Mrass, Volkmar; Li, Mahei Manhai; Peters, Christoph

2017-01-01

Despite the increasing importance of digitization for economy and society, there is few structuring of the very heterogenous kinds of digital work. Representatives from business, politics and science need a basis for the development of strategies to encounter the challenges that result from this digitization. We aim at delivering a contribution to that basis by systematically investigating what different types of digital work exist and by developing a taxonomy. As a first important step towar...

Internet Activities and Developmental Predictors: Gender Differences among Digital Natives

Science.gov (United States)

Johnson, Genevieve Marie

2011-01-01

Widespread adoption of the Internet during the past two decades has produced the first generation of digital natives. Ninety-five children (M[subscript age] = 10.4 years) completed a questionnaire that measured three clusters of variables: 1) Internet use at home and school, 2) peer, school, and home self-esteem, 3) and cognitive abilities…

Molecular nanomagnets: the first 10 years

International Nuclear Information System (INIS)

Gatteschi, Dante; Sessoli, Roberta

2004-01-01

We review here the main achievements reached in the field of magnetic molecules in the first 10 years of activity. After introducing the concept of magnetic molecules we report at some length on the archetypal Mn12Ac, pointing out what is understood and what is still left to do. Other systems will also be reported including Fe8 and Mn4. A section will be devoted to magnetic chains and a final section will give perspectives for future developments

Molecular nanomagnets: the first 10 years

Energy Technology Data Exchange (ETDEWEB)

Gatteschi, Dante E-mail: dante.gatteschi@unifi.it; Sessoli, Roberta

2004-05-01

We review here the main achievements reached in the field of magnetic molecules in the first 10 years of activity. After introducing the concept of magnetic molecules we report at some length on the archetypal Mn12Ac, pointing out what is understood and what is still left to do. Other systems will also be reported including Fe8 and Mn4. A section will be devoted to magnetic chains and a final section will give perspectives for future developments.

Digital holography using a digital photo-camera

Czech Academy of Sciences Publication Activity Database

Sekanina, H.; Pospíšil, Jaroslav

2002-01-01

Roč. 49, č. 13 (2002), s. 2083-2092 ISSN 0950-0340 Institutional research plan: CEZ:AV0Z1010921 Keywords : digital holography * photo-camera Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.717, year: 2002

First-year Engineering Education with the Creative Electrical Engineering Laboratory

Science.gov (United States)

Tsukamoto, Takehiko; Sugito, Tetsumasa; Ozeki, Osamu; Ushiroda, Sumio

The Department of Electrical and Electronic Engineering in Toyota National College of Technology has put great emphasis on fundamental subjects. We introduced the creative electrical engineering laboratory into the first-year engineering education since 1998. The laboratory concentrates on the practice exercise. The final questionnaire of students showed that our first-year education is very effective to promote students motivation and their scholastic ability in engineering.

Psychosocial Stress During First Pregnancy Predicts Infant Health Outcomes in the First Postnatal Year.

Science.gov (United States)

Phelan, A L; DiBenedetto, M R; Paul, I M; Zhu, J; Kjerulff, K H

2015-12-01

To evaluate the impact of psychosocial stress during pregnancy on infant health outcomes in the first postnatal year. A sample of 3000 women completed a stress inventory (the Psychosocial Hassles Scale) during their third trimester before first childbirth. Infant health outcomes were measured via maternal report at 1, 6 and 12 months postpartum. Poisson regression was used to model the effect of maternal stress during pregnancy on infant health outcomes in the first year, controlling for age, race/ethnicity, education, insurance coverage, marital status, and cigarette smoking during pregnancy. Women who were younger, minority, unmarried, publicly insured and without a college degree were more likely to report high levels of prenatal stress. High prenatal stress was a significant predictor of maternal reporting of gastrointestinal illness (p stress was also a significant predictor of urgent care visits (p stress is associated with increased maternal reporting of infant illness, as well as increased frequency of both urgent care visits and emergency department visits.

Women In Engineering Learning Community: What We Learned The First Year

OpenAIRE

LaBoone, Kimberly; Lazar, Maureen; Watford, Bevlee

2007-01-01

The College of Engineering at Virginia Tech reflects national trends with respect to women in engineering. With first year enrollments hovering around 17%, the retention through graduation of these women is critical to increasing the number of women in the engineering profession. When examining year to year retention rates, it is observed that the largest percentage of women drop out of engineering during or immediately following their first year. It is therefore believed that efforts to incr...

Factors affecting Mathematics achievement of first-year secondary ...

African Journals Online (AJOL)

Hennie

2015-08-14

Aug 14, 2015 ... Faculty of Psychology and Educational Sciences, Campus Kulak Kortrijk, KU ... responses of 4,819 first-year secondary school students (Grade ... “its usefulness in science, mathematical and technological activities as well as.

Digital radiography

International Nuclear Information System (INIS)

Rath, M.; Lissner, J.; Rienmueller, R.; Haendle, J.; Siemens A.G., Erlangen

1984-01-01

Using a prototype of an electronic, universal examination unit equipped with a special X-ray TV installation, spotfilm exposures and digital angiographies with high spatial resolution and wide-range contrast could be made in the clinic for the first time. With transvenous contrast medium injection, the clinical results of digital angiography show excellent image quality in the region of the carotids and renal arteries as well as the arteries of the extremities. The electronic series exposures have an image quality almost comparable to the quality obtained with cutfilm changers in conventional angiography. There are certain limitations due to the input field of 25 cm X-ray image intensified used. In respect of the digital angiography imaging technique, the electronic universal unit is fully suitable for clinical application. (orig.) [de

Fate of patients during the first year of dialysis

Directory of Open Access Journals (Sweden)

Selma Siham El Khayat

2013-01-01

Full Text Available Care in dialysis is often associated with significant morbidity and mortality during the first year. Knowledge of its magnitude and causes could improve the prognosis of these patients. The aim of this study was to evaluate the survival and morbidity during the first year of dialysis for patients who initiated their dialysis between January 1, 2009 and December 31, 2009 and to study their possible correlation with baseline status at the beginning of treatment. A multi-center retrospective study was conducted in 11 dialysis centers. Clinical data at the beginning of dialysis and during the following year were collected. Mortality and morbidity risk factors were assessed by comparing different groups. Statistical analysis was performed with SPSS version 11. This study involved 134 patients, 79 men and 55 women, of whom 132 were on hemodialysis and two patients were on peritoneal dialysis. The mean age at initiation of treatment was 54.37 ± 18.09 years. Initial causes of nephropathy were dominated by diabetes (44.02% and hypertension (11.19%. Among these patients, 39.55% had never received prior nephrological follow-up and 64.92% had started renal replacement therapy on an emergency basis. The initial clinical state was dominated by the presence of hypertension (50.74%, diabetes (44.02%, coronary insufficiency (13.43% and heart failure (7.46%. Only 26.86% of the incident patients showed no comorbidity. During the first year of follow-up, 37.31% of the patients experienced at least one episode of comorbidity. Hospitalization was necessary in about half of these cases (17.91% of all patients. The overall mortality rate was 14.17%. One patient received a kidney transplant. The mortality rate in the first year of dialysis was lower in our study than in other series. Regular nephrological follow-up of these patients before they reach end-stage could have a significant influence on survival in dialysis.

Digital literacies

CERN Document Server

Hockly, Nicky; Pegrum, Mark

2014-01-01

Dramatic shifts in our communication landscape have made it crucial for language teaching to go beyond print literacy and encompass the digital literacies which are increasingly central to learners' personal, social, educational and professional lives. By situating these digital literacies within a clear theoretical framework, this book provides educators and students alike with not just the background for a deeper understanding of these key 21st-century skills, but also the rationale for integrating these skills into classroom practice. This is the first methodology book to address not jus

Individual and Relational Predictors of Adjustment in First-Year College Students.

Science.gov (United States)

Holmbeck, Grayson N.; Wandrei, Mary L.

1993-01-01

Assessed differential predictive utility of home-leaving status, family functioning, separation-individuation issues, cognitive constructions of home-leaving process, and personality variables for adjustment during first year of college. Findings from 286 first-year students revealed that separation-individuation, family relations, and personality…

Digital stethoscope: technology update

Directory of Open Access Journals (Sweden)

Swarup S

2018-01-01

Full Text Available Supreeya Swarup,1 Amgad N Makaryus1,2 1Department of Cardiology, Nassau University Medical Center, East Meadow, NY, 2Department of Cardiology, Zucker School of Medicine at Hofstra/Northwell Health, Hempstead, NY, USA Abstract: Cardiovascular disease (CVD is recognized as the leading cause of mortality throughout the world. About one-third of global mortality is attributable to CVD. In addition to clinical presentation, specific clinical exam findings can assist in treating and preventing CVD. CVD may initially manifest as pulmonary pathology, and thus, accurate cardiopulmonary auscultation is paramount to establishing accurate diagnosis. One of the most powerful tools available to physicians is the stethoscope. The stethoscope first emerged in the year 1818, invented by a French physician, René Laennec. Since then, the initial modest monaural wooden tube has evolved into a sophisticated digital device. This paper provides an analysis of the evolution of the stethoscope as well as highlights the advancement made by the modern digital stethoscope including the application of this tool in advancing care for patients suffering from CVD. Keywords: cardiovascular disease, physical exam, diagnosis, treatment

Anatomy of a digital coherent receiver

DEFF Research Database (Denmark)

Borkowski, Robert; Zibar, Darko; Tafur Monroy, Idelfonso

2014-01-01

, orthonormaliation, chromatic dispersion compensation/nonlinear compensation, resampling a nd timing recovery, polarization demultiplexing and equalization, frequency and phase recovery, digital demodulation. We also describe novel subsystems of a digital coherent receiver: modulation format recognition......Digital coherent receivers have gained significant attention in the last decade. The reason for this is that coherent detection, along with digital signal processing (DSP) allows for substantial increase of the channel capacity by employing advanced detection techniques. In this paper, we first...

Continuous measurement of digital game experiences

NARCIS (Netherlands)

Poels, K.; Hoogen, van den W.M.; IJsselsteijn, W.A.; Kort, de Y.A.W.

2008-01-01

In recent years, the game industry has developed a wide array of games and gaming devices, targeted to different age and gender groups and to gamers with various play styles. As such, playing digital games has become a highly popular leisure activity. Over recent years, academic research on digital

Predicting First-Year Achievement by Pedagogy and Skill Development in the First Weeks at University

Science.gov (United States)

Torenbeek, M.; Jansen, E. P. W. A.; Hofman, W. H. A.

2011-01-01

Central in this study is the relationship between the pedagogical approach and generic skill development in the first 10 weeks at university, students' perception of the fit between secondary and university education and first-year achievement. Information regarding the pedagogical approach and generic skill development was gathered through…

Digital device in postextraction implantology : a clinical case presentation

OpenAIRE

Borgonovo, A..E.; Rigaldo, F.; Battaglia, D.; Re, D.; Giannì, A.B.

2014-01-01

Aim. The aim of this work is to describe a case of immediate implant placement after extraction of the upper right first premolar, with the use of CAD/CAM technology, which allows an early digital impression of the implant site with an intraoral scanner (MHT 3D Progress, Verona, Italy). Case Report. A 46-year-old female was referred with a disorder caused by continuous debonding of the prosthetic crown on the upper right first premolar. Clinically, there were no signs, and the evaluation of t...

Digital Forensics and Born-Digital Content in Cultural Heritage Collections. CLIR Publication No. 149

Science.gov (United States)

Kirschenbaum, Matthew G.; Ovenden, Richard; Redwine, Gabriela

2010-01-01

The purpose of this report is twofold: first, to introduce the field of digital forensics to professionals in the cultural heritage sector; and second, to explore some particular points of convergence between the interests of those charged with collecting and maintaining born-digital cultural heritage materials and those charged with collecting…

Dust reddened quasars in first and UKIDSS: Beyond the tip of the iceberg

Energy Technology Data Exchange (ETDEWEB)

Glikman, Eilat [Department of Physics, Middlebury College, Middlebury, VT 05753 (United States); Urrutia, Tanya [Leibniz Institut fr Astrophysik, An der Sternwarte 16, D-14482 Potsdam (Germany); Lacy, Mark [National Radio Astronomy Observatory, Charlottesville, VA (United States); Djorgovski, S. G.; Mahabal, Ashish; Graham, Matthew [California Institute of Technology, Pasadena, CA 91125 (United States); Urry, Meg [Department of Physics and Yale Center for Astronomy and Astrophysics, Yale University, P.O. Box 208121, New Haven, CT 06520-8121 (United States); Croom, Scott [Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006 (Australia); Schneider, Donald P. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Ge, Jian, E-mail: eglikman@middlebury.edu [Astronomy Department, University of Florida, 211 Bryant Space Science Center, P.O. Box 112055, Gainesville, FL 32611 (United States)

2013-12-01

We present the results of a pilot survey to find dust-reddened quasars by matching the Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) radio catalog to the UKIDSS near-infrared survey and using optical data from Sloan Digital Sky Survey to select objects with very red colors. The deep K-band limit provided by UKIDSS allows for finding more heavily reddened quasars at higher redshifts as compared with previous work using FIRST and Two Micron All Sky Survey (2MASS). We selected 87 candidates with K ≤ 17.0 from the UKIDSS Large Area Survey (LAS) First Data Release (DR1), which covers 190 deg{sup 2}. These candidates reach up to ∼1.5 mag below the 2MASS limit and obey the color criteria developed to identify dust-reddened quasars. We have obtained 61 spectroscopic observations in the optical and/or near-infrared, as well as classifications in the literature, and have identified 14 reddened quasars with E(B – V) > 0.1, including 3 at z > 2. We study the infrared properties of the sample using photometry from the Wide-Field Infrared Survey Explorer and find that infrared colors improve the efficiency of red quasar selection, removing many contaminants in an infrared-to-optical color-selected sample alone. The highest-redshift quasars (z ≳ 2) are only moderately reddened, with E(B – V) ∼ 0.2-0.3. We find that the surface density of red quasars rises sharply with faintness, comprising up to 17% of blue quasars at the same apparent K-band flux limit. We estimate that to reach more heavily reddened quasars (i.e., E(B – V) ≳ 0.5) at z > 2 and a depth of K = 17, we would need to survey at least ∼2.5 times more area.

Recurrent infantile digital fibromatosis

African Journals Online (AJOL)

We present a case of an 8-year-old-boy with recurrent infantile digital fibromatosis (IDF) who presented with new ... Keywords: fibrous tumors, inclusion body fibromatosis, infantile digital fibromatosis, spindle cells, Reye tumor .... watch-and-wait strategy for patients with histologically confirmed IDF nodules that do not cause ...

Geospatial Health: the first five years

Directory of Open Access Journals (Sweden)

Jürg Utzinger

2011-11-01

Full Text Available Geospatial Health is an international, peer-reviewed scientific journal produced by the Global Network for Geospatial Health (GnosisGIS. This network was founded in 2000 and the inaugural issue of its official journal was published in November 2006 with the aim to cover all aspects of geographical information system (GIS applications, remote sensing and other spatial analytic tools focusing on human and veterinary health. The University of Naples Federico II is the publisher, producing two issues per year, both as hard copy and an open-access online version. The journal is referenced in major databases, including CABI, ISI Web of Knowledge and PubMed. In 2008, it was assigned its first impact factor (1.47, which has now reached 1.71. Geospatial Health is managed by an editor-in-chief and two associate editors, supported by five regional editors and a 23-member strong editorial board. This overview takes stock of the first five years of publishing: 133 contributions have been published so far, primarily original research (79.7%, followed by reviews (7.5%, announcements (6.0%, editorials and meeting reports (3.0% each and a preface in the first issue. A content analysis of all the original research articles and reviews reveals that three quarters of the publications focus on human health with the remainder dealing with veterinary health. Two thirds of the papers come from Africa, Asia and Europe with similar numbers of contributions from each continent. Studies of more than 35 different diseases, injuries and risk factors have been presented. Malaria and schistosomiasis were identified as the two most important diseases (11.2% each. Almost half the contributions were based on GIS, one third on spatial analysis, often using advanced Bayesian geostatistics (13.8%, and one quarter on remote sensing. The 120 original research articles, reviews and editorials were produced by 505 authors based at institutions and universities in 52 countries

Český trh digitálních agentur: Případová studie Nydrle Digital

OpenAIRE

Vondráková, Tereza

2013-01-01

The master thesis focuses on description of the market of digital advertising agencies that create digital, online and mobile campaigns for their clients. The first part of the thesis addresses the advertising market and its role in the marketing mix. The author gives the summary of the evolution of digital marketing and its tools in the digital and creative procedure of preparing advertising concept. One of the chapters presents changes in media spends towards online and changes of marketing...

Crowdsourcing metrics of digital collections

Directory of Open Access Journals (Sweden)

Tuula Pääkkönen

2015-12-01

Full Text Available In the National Library of Finland (NLF there are millions of digitized newspaper and journal pages, which are openly available via the public website  http://digi.kansalliskirjasto.fi. To serve users better, last year the front end was completely overhauled with its main aim in crowdsourcing features, e.g., by giving end-users the opportunity to create digital clippings and a personal scrapbook from the digital collections. But how can you know whether crowdsourcing has had an impact? How much crowdsourcing functionalities have been used so far? Did crowdsourcing work? In this paper the statistics and metrics of a recent crowdsourcing effort are analysed across the different digitized material types (newspapers, journals, ephemera. The subjects, categories and keywords given by the users are analysed to see which topics are the most appealing. Some notable public uses of the crowdsourced article clippings are highlighted. These metrics give us indications on how the end-users, based on their own interests, are investigating and using the digital collections. Therefore, the suggested metrics illustrate the versatility of the information needs of the users, varying from citizen science to research purposes. By analysing the user patterns, we can respond to the new needs of the users by making minor changes to accommodate the most active participants, while still making the service more approachable for those who are trying out the functionalities for the first time. Participation in the clippings and annotations can enrich the materials in unexpected ways and can possibly pave the way for opportunities of using crowdsourcing more also in research contexts. This creates more opportunities for the goals of open science since source data becomes ­available, making it possible for researchers to reach out to the general public for help. In the long term, utilizing, for example, text mining methods can allow these different end-user segments to

Risk of stress urinary incontinence twelve years after the first pregnancy and delivery.

Science.gov (United States)

Viktrup, Lars; Rortveit, Guri; Lose, Gunnar

2006-08-01

To estimate the impact of onset of stress urinary incontinence in first pregnancy or postpartum period, for the risk of symptoms 12 years after the first delivery. In a longitudinal cohort study, 241 women answered validated questions about stress urinary incontinence after first delivery and 12 years later. Twelve years after first delivery the prevalence of stress urinary incontinence was 42% (102 of 241). The 12-year incidence was 30% (44 of 146). The prevalence of stress urinary incontinence 12 years after first pregnancy and delivery was significantly higher (Ppregnancy (56%, 37 of 66) and in women with onset shortly after delivery (78%, 14 of 18) compared with those without initial symptoms (30%, 44 of 146). In 70 women who had onset of symptoms during first pregnancy or shortly after the delivery but remission 3 months postpartum, a total of 40 (57%) had stress urinary incontinence 12 years later. In 11 women with onset of symptoms during the first pregnancy or shortly after delivery but no remission 3 months postpartum, a total of 10 (91%) had stress urinary incontinence 12 years later. Cesarean during first delivery was significantly associated with a lower risk of incontinence. Other obstetric factors were not significantly associated with the risk of incontinence 12 years later. Patients who were overweight before their first pregnancy were at increased risk. Onset of stress urinary incontinence during first pregnancy or puerperal period carries an increased risk of long-lasting symptoms.

The First Year of College: Understanding Student Persistence in Engineering

Science.gov (United States)

Hayden, Marina Calvet

This research study aimed to expand our understanding of the factors that influence student persistence in engineering. The unique experiences of engineering students were examined as they transitioned into and navigated their first year of college at a public research university in California. Most students provided similar responses with respect to the way they experienced the transition to college and social life. There was, however, wide student response variation regarding their experience of academic life and academic policies, as well as in their level of pre-college academic preparation and financial circumstances. One key finding was that students' experiences during the first year of college varied widely based on the extent to which they had acquired organizational and learning skills prior to college. The study used a mixed methods approach. Quantitative and qualitative data were collected through an online survey and one-on-one interviews conducted with freshman students near the end of their first year of college. The theoretical foundations of this study included Astin's Theory of Student Involvement and Tinto's Theory of Student Departure. The design of the study was guided by these theories which emphasize the critical importance of student involvement with the academic and social aspects of college during the first year of college.

A 3 years retrospective study of survival for zirconia-based single crowns fabricated from intraoral digital impressions.

Science.gov (United States)

Gherlone, Enrico; Mandelli, Federico; Capparè, Paolo; Pantaleo, Giuseppe; Traini, Tonino; Ferrini, Francesco

2014-09-01

To evaluate the clinical performance of glass-ceramic/zirconia crowns fabricated using intraoral digital impressions - a retrospective study with a three-year follow-up. 70 consecutive patients with a total of 86 glass-ceramic/zirconia crowns were treated by a single clinician using standardized clinical and laboratory protocols. A complete digital workflow was adopted for the purpose except for the veneering procedure for the glass-ceramic crowns. Occlusal adjustments were made before the ceramic glazing procedure. Before cementation, all abutments where carefully cleaned with a 70% alcoholic solution and air dried. Cementation was performed using dual-curing, self-adhesive resin cement. Patients were re-examined after 12, 24 and 36 months, to assess crown chipping/fractures. After the three-year follow-up, none of the zirconia-based restoration was lost ("apparent" survival rate 100%) otherwise, the chipping rate of the veneering material increased from 9.3% after 12 months, to 14% after 24 months to 30.2% after 36 months. As a consequence, the "real" success rate after 3 years was 69.8%. After 3 years the success rate of zirconia-based crowns was 69.8%, while the incidence of the chipping was 30.2%. Assuming an exponential increase in chipping rate between 12 and 36 months it can be argued that, among others, the fatigue-mechanism could be advocated as the main factor for the failure of glass-ceramic veneered zirconia especially after 24 months. Copyright © 2014 Elsevier Ltd. All rights reserved.

Recursive sequences in first-year calculus

Science.gov (United States)

Krainer, Thomas

2016-02-01

This article provides ready-to-use supplementary material on recursive sequences for a second-semester calculus class. It equips first-year calculus students with a basic methodical procedure based on which they can conduct a rigorous convergence or divergence analysis of many simple recursive sequences on their own without the need to invoke inductive arguments as is typically required in calculus textbooks. The sequences that are accessible to this kind of analysis are predominantly (eventually) monotonic, but also certain recursive sequences that alternate around their limit point as they converge can be considered.

Interventions to Improve Teaching and Learning in First Year Mathematics Courses

Science.gov (United States)

Engelbrecht, Johann; Harding, Ansie

2015-01-01

In keeping with the national mandate of increasing graduates in the sciences in South Africa, a concerted effort in improving the first year experience becomes imperative. First year mathematics courses commonly provide the base knowledge necessary for progression in different degree programmes at university. Success in mathematics courses…

50 years of first-passage percolation

CERN Document Server

Auffinger, Antonio; Hanson, Jack

2017-01-01

First-passage percolation (FPP) is a fundamental model in probability theory that has a wide range of applications to other scientific areas (growth and infection in biology, optimization in computer science, disordered media in physics), as well as other areas of mathematics, including analysis and geometry. FPP was introduced in the 1960s as a random metric space. Although it is simple to define, and despite years of work by leading researchers, many of its central problems remain unsolved. In this book, the authors describe the main results of FPP, with two purposes in mind. First, they give self-contained proofs of seminal results obtained until the 1990s on limit shapes and geodesics. Second, they discuss recent perspectives and directions including (1) tools from metric geometry, (2) applications of concentration of measure, and (3) related growth and competition models. The authors also provide a collection of old and new open questions. This book is intended as a textbook for a graduate course or as a...

STAR results from the first year at RHIC

Indian Academy of Sciences (India)

Thomas S Ullrich

insight into the state of matter produced. In the first year of .... could be taken as an indication of boost-invariance in the system. This is ..... and the Ministry of Education of China and the National Science Foundation of China. References.

Learning Communities: Foundations for First-Year Students' Development of Pluralistic Outcomes

Science.gov (United States)

Soria, Krista M.; Mitchell, Tania D.

2015-01-01

The purpose of this study was to investigate the associations between first-year undergraduates' (n = 1,701) participation in learning communities and their development of leadership and multicultural competence. The sample included first-year students who were enrolled at six large, public research universities in 2012 and completed the Student…

Effectiveness of Three-Dimensional Digital Animation in Teaching Human Anatomy in an Authentic Classroom Context

Science.gov (United States)

Hoyek, Nady; Collet, Christian; Di Rienzo, Franck; De Almeida, Mickael; Guillot, Aymeric

2014-01-01

Three-dimensional (3D) digital animations were used to teach the human musculoskeletal system to first year kinesiology students. The purpose of this study was to assess the effectiveness of this method by comparing two groups from two different academic years during two of their official required anatomy examinations (trunk and upper limb…

The Relationships among Academic Attitudes, Psychological Attitudes, and the First-Semester Academic Achievement of First-Year College Students

Science.gov (United States)

Reynolds, Amy L.; Weigand, Matthew J.

2010-01-01

This study examined the relationships among academic and psychological attitudes and academic achievement of first-year students. The College Resilience Scale, the Academic Motivation Scale, the College Self-Efficacy Inventory, and the University Environment Scale were administered to 164 first-year undergraduate students enrolled at a large RU/VH…

Comprehension of digital media

International Nuclear Information System (INIS)

Kim, Ju Hwan

2008-11-01

This book is divided four parts. The first part describes media and mark on sign and media, what is the sign?, interpretation of sign and semiotics. The second part is for production sign theory and origin of digital revolution such as the problem of origin of digital revolution, homogeneity of producing goods and sign : triple triangle model for production sign theory, triple triangle model for producing goods, triple triangle model of producing sign and triple triangle model of art works. The third parts deals with development of the media and meaning of digital revolution with four changes : invention of letter, appearance of printed media and establishment modernity, appearance electronic media and mess media and appearance of digital media. The last part mentions ontology of world wide web.

Comprehension of digital media

Energy Technology Data Exchange (ETDEWEB)

Kim, Ju Hwan

2008-11-15

This book is divided four parts. The first part describes media and mark on sign and media, what is the sign?, interpretation of sign and semiotics. The second part is for production sign theory and origin of digital revolution such as the problem of origin of digital revolution, homogeneity of producing goods and sign : triple triangle model for production sign theory, triple triangle model for producing goods, triple triangle model of producing sign and triple triangle model of art works. The third parts deals with development of the media and meaning of digital revolution with four changes : invention of letter, appearance of printed media and establishment modernity, appearance electronic media and mess media and appearance of digital media. The last part mentions ontology of world wide web.

Two-Year Diagnostic Stability in Early-Onset First-Episode Psychosis

Science.gov (United States)

Castro-Fornieles, Josefina; Baeza, Immaculada; de la Serna, Elena; Gonzalez-Pinto, Ana; Parellada, Mara; Graell, Montserrat; Moreno, Dolores; Otero, Soraya; Arango, Celso

2011-01-01

Background: Only one study has used a prospective method to analyze the diagnostic stability of first psychotic episodes in children and adolescents. The Child and Adolescent First-Episode Psychosis Study (CAFEPS) is a 2-year, prospective longitudinal study of early-onset first episodes of psychosis (EO-FEP). Aim: To describe diagnostic stability…

Prognostic stratification of patients with advanced renal cell carcinoma treated with sunitinib: comparison with the Memorial Sloan-Kettering prognostic factors model

International Nuclear Information System (INIS)

Bamias, Aristotelis; Anastasiou, Ioannis; Stravodimos, Kostas; Xanthakis, Ioannis; Skolarikos, Andreas; Christodoulou, Christos; Syrigos, Kostas; Papandreou, Christos; Razi, Evangelia; Dafni, Urania; Fountzilas, George; Karadimou, Alexandra; Dimopoulos, Meletios A; Lampaki, Sofia; Lainakis, George; Malettou, Lia; Timotheadou, Eleni; Papazisis, Kostas; Andreadis, Charalambos; Kontovinis, Loukas

2010-01-01

The treatment paradigm in advanced renal cell carcinoma (RCC) has changed in the recent years. Sunitinib has been established as a new standard for first-line therapy. We studied the prognostic significance of baseline characteristics and we compared the risk stratification with the established Memorial Sloan Kettering Cancer Center (MSKCC) model. This is a retrospective analysis of patients treated in six Greek Oncology Units of HECOG. Inclusion criteria were: advanced renal cell carcinoma not amenable to surgery and treatment with Sunitinib. Previous cytokine therapy but no targeted agents were allowed. Overall survival (OS) was the major end point. Significance of prognostic factors was evaluated with multivariate cox regression analysis. A model was developed to stratify patients according to risk. One hundred and nine patients were included. Median follow up has been 15.8 months and median OS 17.1 months (95% CI: 13.7-20.6). Time from diagnosis to the start of Sunitinib (<= 12 months vs. >12 months, p = 0.001), number of metastatic sites (1 vs. >1, p = 0.003) and performance status (PS) (<= 1 vs >1, p = 0.001) were independently associated with OS. Stratification in two risk groups ('low' risk: 0 or 1 risk factors; 'high' risk: 2 or 3 risk factors) resulted in distinctly different OS (median not reached [NR] vs. 10.8 [95% confidence interval (CI): 8.3-13.3], p < 0.001). The application of the MSKCC risk criteria resulted in stratification into 3 groups (low and intermediate and poor risk) with distinctly different prognosis underlying its validity. Nevertheless, MSKCC model did not show an improved prognostic performance over the model developed by this analysis. Studies on risk stratification of patients with advanced RCC treated with targeted therapies are warranted. Our results suggest that a simpler than the MSKCC model can be developed. Such models should be further validated

First-Year Maternal Employment and Child Development in the First 7 Years

Science.gov (United States)

Brooks-Gunn, Jeanne; Han, Wen-Jui; Waldfogel, Jane

2010-01-01

Using data from the first 2 phases of the NICHD Study of Early Child Care, the authors examine the links between maternal employment in the first 12 months of life and cognitive, social, and emotional outcomes for children at age 3, at age 4.5, and in first grade. Drawing on theory and prior research from developmental psychology as well as…

Rhetoric and the digital humanities

CERN Document Server

Ridolfo, Jim

2015-01-01

The digital humanities is a rapidly growing field that is transforming humanities research through digital tools and resources. Researchers can now quickly trace every one of Issac Newton's annotations, use social media to engage academic and public audiences in the interpretation of cultural texts, and visualize travel via ox cart in third-century Rome or camel caravan in ancient Egypt. Rhetorical scholars are leading the revolution by fully utilizing the digital toolbox, finding themselves at the nexus of digital innovation. Rhetoric and the Digital Humanities is a timely, multidisciplinary collection that is the first to bridge scholarship in rhetorical studies and the digital humanities. It offers much-needed guidance on how the theories and methodologies of rhetorical studies can enhance all work in digital humanities, and vice versa. Twenty-three essays over three sections delve into connections, research methodology, and future directions in this field. Jim Ridolfo and William Hart-Davidson have assemb...

Digital mammography: current state and future aspects

Energy Technology Data Exchange (ETDEWEB)

Fischer, U.; Baum, F. [Womens Health Care Center Goettingen, Diagnostisches Brustzentrum Goettingen, Goettingen (Germany); Hermann, K.P. [Georg-August-Universitaet Goettingen, Abteilung Diagnostische Radiologie, Goettingen (Germany)

2006-01-01

The introduction of digital technique in mammography has been the last step in completing the process of digitalization in diagnostic imaging. Meanwhile, some different digital techniques as well as a couple of different digital mammography systems were developed and have already been available for some years. In this review article, the relevant data of key studies are reported, the current status is defined, and perspectives of digital mammography are described. (orig.)

The Role of Digital Technologies in Learning: Expectations of First Year University Students / Le rôle des technologies numériques dans l’apprentissage : les attentes des étudiants de première année universitaire

Directory of Open Access Journals (Sweden)

Martha Gabriel

2012-02-01

Full Text Available A growing literature suggests that there is a disjuncture between the instructional practices of the education system and the student body it is expected to serve, particularly with respect to the roles of digital technologies. Based on surveys and focus group interviews of first-year students at a primarily undergraduate Canadian university and focus group interviews of professors at the same institution, this study explores the gaps and intersections between students’ uses and expectations for digital technologies while learning inside the classroom and socializing outside the classroom, and the instructional uses, expectations and concerns of their professors. It concludes with recommendations for uses of digital technologies that go beyond information transmission, the need for extended pedagogical discussions to harness the learning potentials of digital technologies, and for pedagogies that embrace the social construction of knowledge as well as individual acquisition. Des études de plus en plus nombreuses suggèrent qu’il existe un écart entre les pratiques d’enseignement dans le système de l’éducation et la population étudiante desservie, notamment en ce qui concerne le rôle des technologies numériques. La présente étude, fondée sur les résultats de sondages et d’entrevues de groupe auprès des étudiants de première année inscrits à une université canadienne principalement axée sur les études de premier cycle, ainsi que sur des entrevues de groupe auprès de professeurs du même établissement, explore les écarts et les concordances entre, d’une part, l’utilisation et les attentes des étudiants relativement aux technologies numériques dans l’apprentissage en classe et dans les relations sociales en dehors des classes, et, d’autre part, l’utilisation de ces technologies dans les pratiques d’enseignement, les préoccupation et les attentes des professeurs. L’étude se conclut par des

Using Neural Networks to Classify Digitized Images of Galaxies

Science.gov (United States)

Goderya, S. N.; McGuire, P. C.

2000-12-01

Automated classification of Galaxies into Hubble types is of paramount importance to study the large scale structure of the Universe, particularly as survey projects like the Sloan Digital Sky Survey complete their data acquisition of one million galaxies. At present it is not possible to find robust and efficient artificial intelligence based galaxy classifiers. In this study we will summarize progress made in the development of automated galaxy classifiers using neural networks as machine learning tools. We explore the Bayesian linear algorithm, the higher order probabilistic network, the multilayer perceptron neural network and Support Vector Machine Classifier. The performance of any machine classifier is dependant on the quality of the parameters that characterize the different groups of galaxies. Our effort is to develop geometric and invariant moment based parameters as input to the machine classifiers instead of the raw pixel data. Such an approach reduces the dimensionality of the classifier considerably, and removes the effects of scaling and rotation, and makes it easier to solve for the unknown parameters in the galaxy classifier. To judge the quality of training and classification we develop the concept of Mathews coefficients for the galaxy classification community. Mathews coefficients are single numbers that quantify classifier performance even with unequal prior probabilities of the classes.

[Epilepsy and epileptic syndromes during the first year of life].

Science.gov (United States)

Durá-Travé, T; Yoldi-Petri, M E; Hualde-Olascoaga, J; Etayo-Etayo, V

To analyse the epidemiological characteristics and the relative distribution of the different types of epilepsy and epileptic syndromes during the first year of life. An analysis was performed of the patient records of all patients with epilepsy diagnosed during their first year of life who were submitted to a developmental check-up in the year 2007. The sample consisted of 60 patients (27 boys and 33 girls). Epidemiological and clinical data were collected, together with the findings from complementary examinations. The diagnostic criteria applied were those of the International League Against Epilepsy. The mean age at the time of diagnosis was 6.3 months. The mean follow-up time was 7.6 years. The aetiology was symptomatic in 40 cases (66.7%), cryptogenic in 16 (26.7%) and idiopathic in four cases (6.7%). Neuroimaging tests detected abnormalities in 34 patients (56.7%). West's syndrome (30%), symptomatic focal epilepsies (23.3%) and epilepsies linked to specific syndromes (16.7%) were the epileptic syndromes with the highest prevalence. Learning disabilities were observed in 82.5% of the children. Most epilepsies that present during the first year of life are symptomatic and/or cryptogenic, and are accompanied by psychoneurological impairment and/or resistance to therapy, which condition cognitive disorders that are eligible for specialised psycho-pedagogical intervention.

Digital image processing

National Research Council Canada - National Science Library

Gonzalez, Rafael C; Woods, Richard E

2008-01-01

Completely self-contained-and heavily illustrated-this introduction to basic concepts and methodologies for digital image processing is written at a level that truly is suitable for seniors and first...

First-Year Seminar Faculty: Recruitment, Supports, Motivators, and Challenges

Science.gov (United States)

Sobel, Karen

2018-01-01

The majority of universities and four-year colleges in the USA currently offer first-year seminars in at least one format. These programs often pride themselves in recruiting from among their institutions' best teachers to lead the seminars. In reality, this process of recruitment to teach in the program, as well as retention of faculty members…

Digital Labour in Chinese Internet Industries

OpenAIRE

Bingqing Xia

2014-01-01

Digital labour has been the subject of considerable research in recent years (Van Dijck 2009, Manzerolle 2010, Dyer-Witheford 2010). But relatively little research has considered professional workers in digital media. This research addresses this gap by focusing on professional workers in the Chinese Internet industries. This paper asks: How are these digital labourers involved in the digital media production? To what extent should we criticise this involvement? Based on detailed empirica...

Three Essays on Digital Evolution

Science.gov (United States)

Zhang, Zhewei

2016-01-01

Digital products are rapidly shaping our world into a ubiquitous computing world. Because of its unique characteristics, digital artifacts are generative and highly evolving through the recombination of existing elements as well as by the invention of new elements. In this thesis, I first propose an evolutionary view to examine how digital…

The Readiness of High School Students to Pursue First Year Physics

Science.gov (United States)

Ramnarain, U.; Molefe, P.

2012-01-01

A high failure rate at first year physics is often attributed to the lack of readiness of high school students to pursue such studies. This research explores this issue and reports on the perceptions of five physics lecturers at a South African university on the preparedness of high school students for first year physics. Qualitative data was…

The Impact of First-Year Seminars on College Students' Life-Long Learning Orientations

Science.gov (United States)

Padgett, Ryan D.; Keup, Jennifer R.; Pascarella, Ernest T.

2013-01-01

Using longitudinal data from the Wabash National Study of Liberal Arts Education, this study measured the impact of first-year seminars on college students' life-long learning orientations. The findings suggest that first-year seminars enhance students' life-long learning orientations and that the effect of first-year seminars is mediated through…

Xeroradiographic anatomy of the equine digit and metacarpophalangeal region

International Nuclear Information System (INIS)

Smallwood, J.E.; Holladay, S.D.

1987-01-01

The purpose of the project was to use xeroradiography to provide a reference for radiographic anatomy of the equine digit and metacarpophalangeal region. The left foredigits and metacarpophalangeal joints of a mature horse and a 30-day-old foal were radiographed, using xeroradiographic techniques. Fifteen xeroradiographs, illustrating standard projections of each area, were selected and appropriately labeled to demonstrate normal radiographic anatomy of these regions. These xeroradiographs have been used successfully for several years to teach radiographic anatomy of these areas to first-year veterinary students at North Carolina State University

Strategies in the digital printing value system

OpenAIRE

Mejtoft, Thomas

2006-01-01

The research objective of this thesis is to identify corporate strategies and strategic decisions in the digital printing business and to analyze how these have evolved due to the introduction of digital printing. This thesis comprises three separate studies, all based on qualitative case methodology. The first study is focused on digital printing houses and how their business strategies have changed due to their investment in digital printing production equipment. The second study concentrat...

Neurocognitive development in first episode psychosis 5 years follow-up

DEFF Research Database (Denmark)

Barder, Helene Eidsmo; Sundet, Kjetil; Rund, Bjørn Rishovd

2013-01-01

, as measured by relapses and diagnostic subgroups. The study is an extension of previous findings from the TIPS-project, reporting stability over the first two years. Sixty-two FEP patients (53% male, age 28 ± 9 years) were neuropsychologically examined at baseline and at 1, 2, and 5 year follow-ups. The test...