Deep optical imaging of AGB circumstellar envelopes

We report results of a program to image the extended circumstellar envelopes of asymptotic giant branch (AGB) stars in dust-scattered Galactic light. The goal is to characterize the shapes of the envelopes to probe the mass-loss geometry and the presence of hidden binary companions. The observations consist of deep optical imaging of 22 AGB stars with high mass loss rates: 16 with the ESO 3.5 m NTT telescope, and the remainder with other telescopes. The circumstellar envelopes are detected in 15 objects, with mass loss rates > 2E-6 Msun/year. The surface brightness of the envelopes shows a strong decrease with Galactic radius, which indicates a steep radial gradient in the interstellar radiation field. The envelopes range from circular to elliptical in shape, and we characterize them by the ellipticity (E = major/minor axis) of iso-intensity contours. We find that about 50 percent of the envelopes are close to circular with E 1.2. We interpret the shapes in terms of populations of single stars and binaries whose envelopes are flattened by a companion. The distribution of E is qualitatively consistent with expectations based on population synthesis models of binary AGB stars. We also find that about 50 percent of the sample exhibit small-scale, elongated features in the central regions. We interpret these as the escape of light from the central star through polar holes, which are also likely produced by companions. Our observations of envelope flattening and polar holes point to a hidden population of companions within the circumstellar envelopes of AGB stars. These companions are expected to play an important role in the transition to post-AGB stars and the formation of planetary nebulae.Comment: 19 pages, 13 figures, color pictures in Appendix, accepted by A&

Architectural Propaganda at the World’s Fairs

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Solid state television camera system Patent

Solid state television camera system consisting of monolithic semiconductor mosaic sensor and molecular digital readout system

Summary of the Status of Harvest Mice, Cricetidae: Reithrodontomys, in Arkansas

Although four species of harvest mice, Reithrodoniomyx, are known to occur in Arkansas, the distributional status of the genus in the state is poorly understood. Recent museum specimens significantly extend the range of R. megalotix and R. fulvescens in the state. R. megalotis is shown to range south through Phillips Co. in eastern Arkansas, and R. fulvescens is shown to range throughout most of the state, now including most of the Mississippi Alluvial Plain. A new specimen of R. humulis from Delaware Co., Oklahoma, suggests that this species probably ranges throughout northwestern Arkansas. R montanus remains known only from Washington Co. in northwestern Arkansas

Book Excerpt: Women of the Black Panther Party Activity and Coloring Book

Welcome to the Women of the Black Panther Party Activity and Coloring Book. It is our pleasure to introduce you to this activity book both as co-contributors to the #SayHerName Women of the Black Panther Party Mural as well as collaborators united in our passion for education, children and preserving the history of the Black Panther Party and its Survival Programs

Within - and between - session reliability of the spider drill test to assess Change of Direction Speed in youth tennis athletes

Agility or Change of Direction Speed (CODS) is a critical physical attribute in a sport such as tennis, which is categorised by frequent and multiple changes of direction. Recently a CODS test called the ‘spider drill’ has been used to assess tennis athletes’ ability to change direction. To the authors’ knowledge, no study has solely assessed its reliability and compared this with other commonly-used CODS tests; thus, this was the aim of the study. Ten nationally ranked youth tennis athletes (age: 15.1 ± 2.6; mass: 66.4 + 17.2 kg; height: 163.0 + 16.2 cm) completed three trials of the spider drill, modified t-test and pro-agility test on two separate testing occasions. All CODS tests had low typical percentage error, both within-sessions (CV = 1.8 - 4.1%), and between session (CV = 1.2 - 3.7%). The SEM was also consistent within tests both within- and between- testing sessions. Within-session test-retest consistency illustrates strong reliability for the spider drill (ICC = 0.93, 0.95), modified t-test (ICC = 0.79, 0.83), however for pro-agility session 2 fell outside of the accepted threshold (ICC = 0.88, 0.69). These trends were similar when assessing between-session consistency, with both the spider drill and modified t-test providing high levels of reliability (ICC = 0.95 and 0.97 respectively). However, the pro-agility fell outside of the accepted threshold (ICC = 0.66), with 95% confidence intervals wide-ranging in nature (95% CI: 0.11 - 0.9). These results suggest that the spider drill and modified t-test are both reliable tests when measuring CODS within youth tennis athletes. Strength and conditioning practitioners could consider changes in excess of ± 1.1% as meaningful (based off the SDD) when assessing CODS through the spider drill or modified t-test within youth tennis athletes