Psychological Bases for Children\u27s Preferences for Picture Sequences

No abstract provided by author

Psychological Bases for Children\u27s Preferences for Picture Sequences

No abstract provided by author

Near infrared spectroscopy of the type IIn SN 2010jl: evidence for high velocity ejecta

The Type IIn supernova SN 2010jl was relatively nearby and luminous, allowing detailed studies of the near-infrared (NIR) emission. We present 1 - 2.4 micron spectroscopy over the age range of 36 - 565 days from the earliest detection of the supernova. On day 36, the H lines show an unresolved narrow emission component along with a symmetric broad component that can be modeled as the result of electron scattering by a thermal distribution of electrons. Over the next hundreds of days, the broad components of the H lines shift to the blue by 700 km/s, as is also observed in optical lines. The narrow lines do not show a shift, indicating they originate in a different region. He I 1.0830 and 2.0587 micron lines both show an asymmetric broad emission component, with a shoulder on the blue side that varies in prominence and velocity from -5500 km/s on day 108 to -4000 km/s on day 219. This component may be associated with the higher velocity flow indicated by X-ray observations of the supernova. The absence of the feature in the H lines suggests that this is from a He rich ejecta flow. The He I 1.0830 micron feature has a narrow P Cygni line, with absorption extending to ~100 km/s and strengthening over the first 200 days, and an emission component which weakens with time. At day 403, the continuum emission becomes dominated by a blackbody spectrum with a temperature of ~1900 K, suggestive of dust emission.Comment: 17 pages, 18 figure

Peer Acceptance and Friendship as Predictors of Early Adolescents’ Adjustment Across the Middle School Transition

This study examines several aspects of adolescents’ pretransition peer relationships as predictors of their adjustment to middle school. Participants were 365 students (175 boys; 99% Caucasian) involved in the Time 1 (the spring of fifth grade) and Time 2 (the fall of sixth grade) assessments. Adolescents completed measures that assessed peer acceptance, number of friends, the quality of a specific mutual friendship, loneliness, depression, self-esteem, and involvement in school. Academic achievement and absentee data were obtained from student files. Regression analyses indicated that the pretransition peer variables predicted posttransition loneliness, self-esteem, school involvement, and academic achievement. The patterns of prediction varied slightly for each adjustment variable, with the most robust relationship being between peer acceptance and achievement. Results of repeated-measures MANOVAs indicated no differential changes in adjustment across time by gender. Implications for including a peer component in programs that prepare students for the middle school transition are discussed

Peer Acceptance and Friendship as Predictors of Early Adolescents\u27 Adjustment Across the Middle School Transition

This study examines several aspects of adolescents\u27 pretransition peer relationships as predictors of their adjustment to middle school. Participants were 365 students (175 boys; 99% Caucasian) involved in the Time 1 (the spring of fifth grade) and Time 2 (the fall of sixth grade) assessments. Adolescents completed measures that assessed peer acceptance, number of friends, the quality of a specific mutual friendship, loneliness, depression, self-esteem, and involvement in school. Academic achievement and absentee data were obtained from student files. Regression analyses indicated that the pretransition peer variables predicted posttransition loneliness, self-esteem, school involvement, and academic achievement. The patterns of prediction varied slightly for each adjustment variable, with the most robust relationship being between peer acceptance and achievement. Results of repeated-measures MANOVAs indicated no differential changes in adjustment across time by gender. Implications for including a peer component in programs that prepare students for the middle school transition are discussed

The Status of NASA's Wide-Field Meteor Camera Network and Preliminary Results

NASA's Meteoroid Environment Office (MEO) recently established two wide-field cameras to detect meteors in the millimeter-size-range. This paper outlines the concepts of the system, the hardware and software, and results of 3,440 orbits seen from December 13, 2012 until May 14, 2014

Optical Meteor Fluxes and Application to the 2015 Perseids

This paper outlines new methods to measure optical meteor fluxes for showers and sporadic sources. Many past approaches have found the collecting area of a detector at a fixed 100 km altitude, but this approach considers the full volume, finding the area in two km height intervals based on the position of the shower or sporadic source radiant and the population's velocity. Here, the stellar limiting magnitude is found every 10 minutes during clear periods and converted to a limiting meteor magnitude for the shower or sporadic source having fluxes measured, which is then converted to a limiting mass. The final output is a mass limited flux for meteor showers or sporadic sources. Presented are the results of these flux methods as applied to the 2015 Perseid meteor shower as seen by the Meteoroid Environment Office's eight wide-field cameras. The peak Perseid flux on the night of August 13, 2015, was measured to be 0.002989 meteoroids/km2/hr down to 0.00051 grams, corresponding to a ZHR of 100.7

The Meteoroid Fluence at Mars Due to Comet C/2013 A1 (Siding Spring)

Long-period comet C/2013 A1 (Siding Spring) will experience a close encounter with Mars on 2014 Oct 19. A collision between the comet and the planet has been ruled out, but the comet's coma may envelop Mars and its man-made satellites. By the time of the close encounter, five operational spacecraft will be present near Mars. Characterizing the coma is crucial for assessing the risk posed to these satellites by meteoroid impacts. We present an analytic model of cometary comae that describes the spatial and size distributions of cometary dust and meteoroids. This model correctly reproduces, to within an order of magnitude, the number of impacts recorded by Giotto near 1P/Halley [1] and by Stardust near comet 81P/Wild 2 [2]. Applied to Siding Spring, our model predicts a total particle fluence near Mars of 0.02 particles per square meter. In order to determine the degree to which Siding Spring's coma deviates from a sphere, we perform numerical simulations which take into account both gravitational effects and radiative forces. We take the entire dust component of the coma and tail continuum into account by simulating the ejection and evolution of dust particles from comet Siding Spring. The total number of particles simulated is essentially a free parameter and does not provide a check on the total fluence. Instead, these simulations illustrate the degree to which the coma of Siding Spring deviates from the perfect sphere described by our analytic model (see Figure). We conclude that our analytic model sacrifices less than an order of magnitude in accuracy by neglecting particle dynamics and radiation pressure and is thus adequate for order-of-magnitude fluence estimates. Comet properties may change unpredictably and therefore an analytic coma model that enables quick recalculation of the meteoroid fluence is highly desirable. NASA's Meteoroid Environment Office is monitoring comet Siding Spring and taking measurements of cometary brightness and dust production. We will discuss our coma model and nominal fluence taking the latest observations into account

When the Sky Falls NASA's Response to Bright Bolide Events Over Continental USA

Being the only U.S. Government entity charged with monitoring the meteor environment, the Meteoroid Environment Office (MEO) has deployed a network of allsky and wide field meteor cameras, along with the appropriate software tools to quickly analyze data from these systems. However, the coverage of this network is still quite limited, forcing the incorporation of data from other cameras posted to the internet in analyzing many of the fireballs reported by the public and media. Information on these bright events often needs to be reported to NASA Headquarters by noon the following day; thus a procedure has been developed that determines the analysis process for a given fireball event based on the types and amount of data available. The differences between these analysis processes are shown by looking at four meteor events that the MEO responded to, all of which were large enough to produce meteorites

Allylic Amination and Carbon–carbon Double Bond Transposition Catalyzed by Cobalt(II) azodioxide Complexes

The unusual cobalt(II) diphenylazodioxide complex salts [Co(az)4](PF6)2 and [Co(bpy)(az)2](PF6)2 have been shown to catalyze the allylic amination/C–C double bond transposition reaction of 2-methyl-2-pentene with PhNHOH, with a turnover number of about 4. The mechanism is proposed to involve a nitroso-ene-like transfer of a PhNO moiety from the azodioxide ligand to the alkene, followed by reduction of the organic product to yield a cobalt(III) intermediate, which is itself reduced back to cobalt(II) by PhNHOH, regenerating PhNO. Hetero-Diels-Alder trapping experiments suggest that an “off-metal” mechanism, in which PhNO is released from the cobalt complexes and reacts with the alkenes, is operative, in contrast to an “on-metal” mechanism observed by Nicholas and coworkers for [Fe(az)3](FeCl4)2