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Transit spectroscopy is the most promising path toward characterizing nearby terrestrial planets at mid-infrared wavelengths in the next 20 years. The Spitzer Space telescope has achieved moderately good mid-infrared photometric precision in observations of transiting planets, but the intrinsic photometric stability of mid-IR detectors themselves has not been reported in the scientific or technical literature. Here, we evaluated the photometric precision of a JWST MIRI prototype mid-infrared Si:As impurity band conduction detector, using time-series data taken under flood illumination. These measurements of photometric precision were conducted over periods of 10 hours, representative of the time required to observe an exoplanet transit. After selecting multiple sub-regions with a size of 10x10 pixels and compensating for a gain change caused by our warm detector control electronics for the selected sub-regions, we found that the photometric precision was limited to 26.3ppm at high co-added signal levels due to a gain variation caused by our warm detector control electronics. The photometric precision was improved up to 12.8ppm after correcting for the gain drift. We also translated the photometric precision to the expected spectro-photometric precision, assuming that an optimized densified pupil spectrograph is used in transit observations. We found that the spectro-photometric precision of an optimized densified pupil spectrograph when used in transit observations is expected to be improved by the square root of the number of pixels per a spectral resolution element. At the high co-added signal levels, the total noise could be reduced down to 7ppm, which was larger by a factor of 1.3 than the ideal performance that was limited by the Poisson noise and readout noise. The systematic noise hidden behind the simulated transit spectroscopy was 1.7ppm., Comment: 16 pages, 10 figures and 2 tables, it has been accepted by PASP

The examination of historical trend data on the number and percent of students lost from public school enrollment prior to graduation from high school is becoming increasingly important since distinct trends are emerging on a regional basis. This study examines regional trends in Texas on the number and percent of students lost from public high school enrollment prior to graduation with a high school diploma. A comparative analysis of 1985-86, 2005-06 and 2006-07 attrition rates in Texas' 20 education service center (ESC) regions shows that eight Texas regions have persistently higher rates of losing students from public school enrollment. Education service center regions with traditionally high attrition rates include: ESC Region 1 (Edinburg), ESC Region 4 (Houston), ESC Region 10 (Richardson), ESC Region 13 (Austin), ESC Region 19 (El Paso), and ESC Region 20 (San Antonio). The highest attrition rates are primarily concentrated in regions with the largest student enrollment counts, particularly those in urban areas and those with the largest low-income and minority populations. Schools and communities in Texas and nationwide must work together to improve school holding power and student success. (Contains 12 exhibits.)

This study compared the effects of using voice mail (v-mail) to electronic mail (e-mail) over the Internet to provide student feedback using Media Richness Theory (MRT) and Social Presence Theory (SPT) as the theoretical framework. MRT and SPT would predict that v-mail would be perceived as higher than e-mail in media richness and social presence. Results indicate, however, that while v-mail was perceived to have significantly higher social presence, the two media were not significantly different in terms of perceived media richness. Both e-mail and v-mail were perceived as capable of providing a reasonably high quality of feedback. Implications of these findings are discussed. Constructs and measures are appended. (Contains 33 references.) (Author)

This policy brief presents an in-depth look at the dropout issue in Texas in the context of 1986 state legislation that mandated that the schools and state education agency ensure that at least 95 % of Texas youth complete high school. Findings from a study by the Intercultural Development Research Association (IDRA), using a high school attrition formula and the review and analysis of secondary data, suggested that 86,000 students had not graduated from Texas public high schools that year. By 1998, the estimated cumulative number of dropouts was much higher, at more than 1.2 million, and study findings show that 43% of the 1993-94 freshman class did not graduate in what should have been their senior year. The costs to the state in foregone income, lost tax revenue, and direct costs of the criminal justice and welfare systems have been enormous. The student attrition rate was highest in major urban districts (51%) and lowest in rural districts (28%). Racial and ethnic minority group students were more likely to be lost from public school enrollment than were White nonHispanic students. The Texas Education Agency has reported much lower dropout rates, suggesting that in 1996-97, only 9.1% (estimated longitudinal rate) did not graduate. One of the recommendations coming from this study is that state and district dropout reporting be made more accurate. Other recommendations center on modifying definitions and policy requirements to reflect the realities of the situation, and establishing monitoring, reporting, and prevention activities at the local school district level. (Contains 17 references.) (SLD)