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Full-Text Articles in Physics

Interpreting Force Concept Inventory Scores: Normalizedgain And Sat Scores, Vincent P. Coletta, Jeffrey A. Phillips May 2007

Interpreting Force Concept Inventory Scores: Normalizedgain And Sat Scores, Vincent P. Coletta, Jeffrey A. Phillips

Physics Faculty Works

Preinstruction SAT scores and normalized gains (G) on the force concept inventory (FCI) were examined for individual students in interactive engagement (IE) courses in introductory mechanics at one high school (N=335) and one university (N=292), and strong, positive correlations were found for both populations (r=0.57 and r=0.46, respectively). These correlations are likely due to the importance of cognitive skills and abstract reasoning in learning physics. The larger correlation coefficient for the high school population may be a result of the much shorter time interval between taking the SAT and studying mechanics, because the SAT may provide a more current measure …


Depleted Carbon Monoxide In Fragment C Of The Jupiter-Family Comet 73p/Schwassmann-Wachmann 3, M. Disanti, W. Anderson, G. Villanueva, B. Bonev, K. Magee-Sauer, E. Gibb, M. Mumma May 2007

Depleted Carbon Monoxide In Fragment C Of The Jupiter-Family Comet 73p/Schwassmann-Wachmann 3, M. Disanti, W. Anderson, G. Villanueva, B. Bonev, K. Magee-Sauer, E. Gibb, M. Mumma

Physics Faculty Works

Carbon monoxide emission was targeted in fragment C of the recently split Jupiter-family comet 73P/Schwassmann-Wachmann 3 during its 2006 apparition, using the Cryogenic Echelle Spectrograph (CSHELL) at the NASA IRTF on Mauna Kea, Hawaii. Simultaneous sounding with H2O near 4.65 μm revealed highly depleted CO, consistent with a mixing ratio of 0.5% ± 0.13%. Along with depleted CH3OH but nearly normal HCN, this may indicate that this comet formed in the inner giant planets' region or, alternatively, that it formed relatively late, after significant clearing of the protosolar nebula.


The Shape Of Galaxy Cluster Dark Matter Haloes: Systematics Of Its Imprint On Cluster Gas And Comparison To Observations, Ricardo Flores, Brandon Allgood, Andrey Kravtsov, Joel Primack, David Buote, James Bullock May 2007

The Shape Of Galaxy Cluster Dark Matter Haloes: Systematics Of Its Imprint On Cluster Gas And Comparison To Observations, Ricardo Flores, Brandon Allgood, Andrey Kravtsov, Joel Primack, David Buote, James Bullock

Physics Faculty Works

We study predictions for galaxy cluster observables that can test the statistics of dark matter halo shapes expected in a flat Λ cold dark matter (CDM) universe. We present a simple analytical model for the prediction of cluster-scale X-ray observations, approximating clusters as isothermal systems in hydrostatic equilibrium, and dark matter haloes as ellipsoids with uniform axial ratios (homeoidal ellipsoids). We test the model against high-resolution, hydrodynamic cluster simulations to gauge its reliability. We find that this simple prescription does a good job of predicting cluster X-ray ellipticities compared to the simulations as long as one focuses on cluster regions …


Warm Hcn, C2h2, And Co In The Disk Of Gv Tau, Erika Gibb, K. Van Brunt, S. Brittain, T Rettig May 2007

Warm Hcn, C2h2, And Co In The Disk Of Gv Tau, Erika Gibb, K. Van Brunt, S. Brittain, T Rettig

Physics Faculty Works

We present the first high-resolution, ground-based observations of HCN and C2H2 toward the T Tauri binary star system GV Tau. We detected strong absorption due to HCN ν3 and weak C2H2 [ν3 and ν2 + (ν4 + ν5)img1.gif] absorption toward the primary (GV Tau S) but not the infrared companion. We also report CO column densities and rotational temperatures, and present abundances relative to CO of HCN/CO ~ 0.6% and C2H/CO ~ 1.2% and an upper limit for CH4/CO < 0.37% toward GV Tau S. Neither HCN nor C2H2 were detected toward the infrared companion, and results suggest that abundances may differ between the two sources.


Fractal Holography: A Geometric Re-Interpretation Of Cosmological Large Scale Structure, Jonas R. Mureika May 2007

Fractal Holography: A Geometric Re-Interpretation Of Cosmological Large Scale Structure, Jonas R. Mureika

Physics Faculty Works

The fractal dimension of large-scale galaxy clustering has been demonstrated to be roughly DF∼2 from a wide range of redshift surveys. If correct, this statistic is of interest for two main reasons: fractal scaling is an implicit representation of information content, and also the value itself is a geometric signature of area. It is proposed that the fractal distribution of galaxies may thus be interpreted as a signature of holography (``fractal holography''), providing more support for current theories of holographic cosmologies. Implications for entropy bounds are addressed. In particular, because of spatial scale invariance in the matter distribution, …


Interpreting Force Concept Inventory Scores: Normalized Gain And Sat Scores, Vincent P. Coletta, Jeffrey A. Phillips, Jeffrey J. Steinert May 2007

Interpreting Force Concept Inventory Scores: Normalized Gain And Sat Scores, Vincent P. Coletta, Jeffrey A. Phillips, Jeffrey J. Steinert

Physics Faculty Works

Preinstruction SAT scores and normalized gains (G) on the force concept inventory (FCI) were examined for individual students in interactive engagement (IE) courses in introductory mechanics at one high school (N=335) and one university (N=292), and strong, positive correlations were found for both populations (r=0.57 and r=0.46, respectively). These correlations are likely due to the importance of cognitive skills and abstract reasoning in learning physics. The larger correlation coefficient for the high school population may be a result of the much shorter time interval between taking the SAT and studying mechanics, …


Global Profiles Of Compressional Ultralow Frequency Wave Power At Geosynchronous Orbit And Their Response To The Solar Wind, Jeff Sanny, D. Judnick, M. B. Moldwin, David Berube, D. G. Sibeck May 2007

Global Profiles Of Compressional Ultralow Frequency Wave Power At Geosynchronous Orbit And Their Response To The Solar Wind, Jeff Sanny, D. Judnick, M. B. Moldwin, David Berube, D. G. Sibeck

Physics Faculty Works

We investigate the global local-time profiles of compressional wave power in three ultralow frequency (ULF) bands corresponding to Pc3, Pc4, and Pc5 pulsations using magnetic field data from the geosynchronous GOES satellites. The global power profiles of the three frequency bands are studied for low, moderate, and high levels of geomagnetic activity based on the Dst index. We also consider the seasonal variation of the ULF power profiles, as well as the effects of solar wind and interplanetary magnetic field (IMF) parameters. For high geomagnetic activity, we find that the greatest power is associated with compressional Pc5 pulsations in the …


The Abundance Of Carbon Dioxide Ice In The Quiescent Intracloud Medium, D. Whittet, S. Shenoy, E. Bergin, J. Chiar, P. Gerakines, E. Gibb, G. Melnick, D. Neufeld Jan 2007

The Abundance Of Carbon Dioxide Ice In The Quiescent Intracloud Medium, D. Whittet, S. Shenoy, E. Bergin, J. Chiar, P. Gerakines, E. Gibb, G. Melnick, D. Neufeld

Physics Faculty Works

We present new observations with the Infrared Spectrograph on board the Spitzer Space Telescope of the solid-CO2 absorption feature near 15 μm in the spectra of eight field stars behind the Taurus complex of dark clouds. Solid CO2 is detected in six lines of sight. New results are combined with previous data to investigate the correlation of CO2 column density with those of other major ice constituents (H2O and CO) and with extinction. CO2 is shown to display a "threshold extinction" effect, i.e., a minimum extinction (A0 = 4.3 ± 1.0 mag) required for detection, behavior similar to that previously …


Structural Fingerprinting In The Transmission Electron Microscope : Overview And Opportunities To Implement Enhanced Strategies For Nanocrystal Identification Jan 2007

Structural Fingerprinting In The Transmission Electron Microscope : Overview And Opportunities To Implement Enhanced Strategies For Nanocrystal Identification

Physics Faculty Works

No abstract provided.