Results 21 to 30 of about 4,576 (128)

“It's Just a Hot Mess”: Supporting Teacher Praxis to Challenge Barriers for Multilingual Learners

Science Education, Volume 109, Issue 4, Page 1022-1047, July 2025.
ABSTRACT This paper examines a professional learning (PL) program for upper elementary teachers focused on developing instructional practices to support multilingual learners (MLLs) in science. The PL sought to support teachers' praxis, which we describe as their sense of agency to critically analyze and take action against barriers to MLLs ...
Emily V. Reigh, Emily Adah Miller, Ayça K. Fackler, Maria Chiara Simani   +3 more
wiley   +1 more source

Variability of Active Galactic Nuclei from the Optical to X-ray Regions

, 2009
Some progress in understanding AGN variability is reviewed. Reprocessing of X-ray radiation to produce significant amounts of longer-wavelength continua seems to be ruled out. In some objects where there has been correlated X-ray and optical variability,
Boiler T. H., C. Martin Gaskell, Done C., Elizabeth S. Klimek, Gaskell C. M., Gaskell C. M., Gaskell C. M., Kurochkin N. G., Longo G., Lub J., Lyutyi V. M., Lyutyi V. M., Negoro H., Oknyanskij V. L., Paltani S., Shakura N. I., Sharov A. S., Smith H. J., Takeuchi M.   +18 more
core   +1 more source

New constraints on the continuum-emission mechanism of AGN: Intensive monitoring of NGC 7469 in the X-ray and ultraviolet [PDF]

, 1998
We have undertaken near-continuous monitoring of the Seyfert 1 galaxy NGC 7469 in the X-ray with RXTE over a ~30d baseline. The source shows strong variability with a root-mean-square (rms) amplitude of ~16 per cent, and peak-to-peak variations of a ...
Abramowicz M. A., B. M. Peterson, Brandt W. N., Courvoisier T. J.-L., Done C., Fabian A. C., George I. M., Ghisellini G., Gondek D., Green A. R., Guilbert P. W., Guilbert P. W., I. M. George, J. Clavel, K. Nandra, M. A. Malkan, Marshall N., Matt G., Molendi S., Nandra K., Papadakis I., R. A. Edelson, R. F. Mushotzky, Santos-Lleo M., Shakura N. I., Sunyaev R. A., T. J. Turner, Zdziarski A. A.   +27 more
core   +3 more sources

Course‐Based Teacher Professional Communities (With District and Union Support) at the Center of Three‐Dimensional Science Teaching

Science Education, Volume 109, Issue 4, Page 1048-1071, July 2025.
ABSTRACT This study focuses on how two school districts managed and changed the instructional core—student learning goals, instructional resources and strategies, and assessments—in their required high school biology course as they responded to new state science standards based on the Next Generation Science Standards (NGSS).
Christie Morrison Thomas, Charles W. Anderson   +1 more
wiley   +1 more source

Systematizing Decisions in Design‐Based Research: From Theory to Design

Science Education, Volume 109, Issue 2, Page 523-536, March 2025.
ABSTRACT There is a general consensus that design‐based research (DBR) is a genre of approaches in education research to design interventions for specific problems with the aim to gain an understanding of how they work in the problem context. While there is a considerable body of literature discussing the epistemic and methodological aspects of DBR, we
Markus Obczovsky, Angelika Bernsteiner, Claudia Haagen‐Schützenhöfer, Thomas Schubatzky   +3 more
wiley   +1 more source

Correlated X-ray and Optical Variability in Mkn 509

, 2007
We present results of a 3 year monitoring campaign of the Seyfert 1 galaxy Markarian 509, using X-ray data from the Rossi X-ray Timing Explorer (RXTE) and optical data taken by the SMARTS consortium. Both light curves show significant variations, and are
Cooke B. A., H. Richard Miller, Kevin Marshall, Pounds K. A., Reynolds C. S., Timmer J., Uttley P., Wesley T. Ryle   +7 more
core   +1 more source

A Brief History of AGN [PDF]

, 1999
Astronomers knew early in the twentieth century that some galaxies have emission-line nuclei. However, even the systematic study by Seyfert (1943) was not enough to launch active galactic nuclei (AGN) as a major topic of astronomy.
Antonucci R. A. R., Baldwin J. A., Bennett A. S., Blandford R. D., Collin-Souffrin S., Collin-Souffrin S., Collin-Souffrin S., Collin-Souffrin S., Courvoisier T. J.-L., Edge D. O., Elvis M., Fath E. A., Frank J., Ginzburg V. L., Gregory A. Shields, Heckman T. M., Hoyle F., Hoyle F., Kellermann K. I., Marshall N., Matthews T. A., Mills B. Y., Morris D., Orr M. J. L., Penston M. V., Pounds K., Pringle J. E., Ryle M., Ryle M., Scott P. F., Setti G., Shakura N. I., Shields G. A., Shklovskii I. S., Shklovskii I. S., Sholomitsky G. B., Slipher V. M., Souffrin S., Souffrin S., Terlevich R., Ulrich M.-H., Wilkes B. J., Wilkes B. J.   +42 more
core   +2 more sources

Connection between the Accretion Disk and Jet in the Radio Galaxy 3C 111

, 2011
We present the results of extensive multi-frequency monitoring of the radio galaxy 3C 111 between 2004 and 2010 at X-ray (2.4--10 keV), optical (R band), and radio (14.5, 37, and 230 GHz) wave bands, as well as multi-epoch imaging with the Very Long ...
Abdo, Alan P. Marscher, Alex Markowitz, Anne Lähteenmäki, Baars, Blandford, Brandon Harrison, Brian W. Taylor, Chatterjee, Chatterjee, Edelson, Edelson, Elizabeth Rivers, Eracleous, Eracleous, Esin, Fanaroff, Greene, Gurwell, Gómez, Götz, Hartman, Hugh D. Aller, Ian M. McHardy, Iván Agudo, Jorstad, Jorstad, José L. Gómez, Kadler, Kazanas, Larson, Lewis, Livio, Margo F. Aller, Mark Gurwell, Markoff, Markowitz, Markowitz, Markowitz, Marshall, Merja Tornikoski, Mirabel, Nandra, Nayakshin, Nowak, Papadakis, Pounds, Preuss, Rachford, Richard E. Rothschild, Ritaban Chatterjee, Rivers, Sambruna, Schlegel, Shepherd, Svetlana G. Jorstad, Ulvestad, Vaughan, Vestergaard, Vlahakis, Young   +60 more
core   +1 more source

A complete sample of Seyfert galaxies selected at 1/4 keV [PDF]

, 2001
We have used the ROSAT Bright Source Catalogue to extract a complete sample of sources selected in the band from 0.1-0.4 keV. This 1/4 keV-selected sample is comprised of 54 Seyfert galaxies, 25 BL Lacertae objects, 4 clusters and 27 Galactic stars or ...
Edelson, R., Goad, M. R., Malkan, M. A., Vaughan, S., Warwick, R. S.   +4 more
core   +3 more sources

Long-term X-ray variability of quasars in the Lockman Hole field observed with ROSAT

, 2002
An improved method is utilized to estimate the X-ray power spectral densities (PSD) and the variation time scales of three quasars in the Lockman Hole field. Five archival ROSAT PSPC data covering two year range are analyzed.
Ezoe, Yu-ichiro, Hasinger, Gunter, Iyomoto, Naoko, Makishima, Kazuo   +3 more
core   +1 more source