Testing of the LSST's photometric calibration strategy at the CTIO 0.9 meter telescope

The calibration hardware system of the Large Synoptic Survey Telescope (LSST) is designed to measure two quantities: a telescope's instrumental response and atmospheric transmission, both as a function of wavelength. First of all, a "collimated beam projector" is designed to measure the instrumental response function by projecting monochromatic light through a mask and a collimating optic onto the telescope. During the measurement, the light level is monitored with a NIST-traceable photodiode. This method does not suffer from stray light effects or the reflections (known as ghosting) present when using a flat-field screen illumination, which has a systematic source of uncertainty from uncontrolled reflections. It allows for an independent measurement of the throughput of the telescope's optical train as well as each filter's transmission as a function of position on the primary mirror. Second, CALSPEC stars can be used as calibrated light sources to illuminate the atmosphere and measure its transmission. To measure the atmosphere's transfer function, we use the telescope's imager with a Ronchi grating in place of a filter to configure it as a low resolution slitless spectrograph. In this paper, we describe this calibration strategy, focusing on results from a prototype system at the Cerro Tololo Inter-American Observatory (CTIO) 0.9 meter telescope. We compare the instrumental throughput measurements to nominal values measured using a laboratory spectrophotometer, and we describe measurements of the atmosphere made via CALSPEC standard stars during the same run

Perceptions of College Students with Autism Spectrum Disorder on the Transition to Remote Learning During the COVID-19 Pandemic

COVID-19 caused a major shift in how college students, including those with disabilities, received their education during the Spring 2020 semester. The rapid shift to remote learning resulted in new challenges, but also, some benefits for students. This study presents the results of open-ended responses of a cohort of 31 students with autism spectrum disorder (ASD) who were part of a larger study and enrolled in very- to highly competitive institutions (as rated by U.S. News and World Report) during the Spring 2020 semester regarding their experiences, both positive and negative, in shifting to remote learning. The students described advantages, including personal and academic benefits with remote learning as well as disadvantages. These problematic areas included the structure and infrastructure of course delivery, environmental factors, social factors, and personal factors. Specific examples of each are presented to help richly capture the experiences of these students during an unprecedented period in history

Penning traps with unitary architecture for storage of highly charged ions

Penning traps are made extremely compact by embedding rare-earth permanent magnets in the electrode structure. Axially-oriented NdFeB magnets are used in unitary architectures that couple the electric and magnetic components into an integrated structure. We have constructed a two- magnet Penning trap with radial access to enable the use of laser or atomic beams, as well as the collection of light. An experimental apparatus equipped with ion optics is installed at the NIST electron beam ion trap (EBIT) facility, constrained to fit within 1 meter at the end of a horizontal beamline for transporting highly charged ions. Highly charged ions of neon and argon, extracted with initial energies up to 4000 eV per unit charge, are captured and stored to study the confinement properties of a one-magnet trap and a two-magnet trap. Design considerations and some test results are discussed

Physical characteristics and non-keplerian orbital motion of "propeller" moons embedded in Saturn's rings

We report the discovery of several large "propeller" moons in the outer part of Saturn's A ring, objects large enough to be followed over the 5-year duration of the Cassini mission. These are the first objects ever discovered that can be tracked as individual moons, but do not orbit in empty space. We infer sizes up to 1--2 km for the unseen moonlets at the center of the propeller-shaped structures, though many structural and photometric properties of propeller structures remain unclear. Finally, we demonstrate that some propellers undergo sustained non-keplerian orbit motion. (Note: This arXiv version of the paper contains supplementary tables that were left out of the ApJL version due to lack of space).Comment: 9 pages, 4 figures; Published in ApJ

Obesity alters the muscle protein synthetic response to nutrition and exercise

Improving the health of skeletal muscle is an important component of obesity treatment. Apart from allowing for physical activity, skeletal muscle tissue is fundamental for the regulation of postprandial macronutrient metabolism, a time period that represents when metabolic derangements are most often observed in adults with obesity. In order for skeletal muscle to retain its capacity for physical activity and macronutrient metabolism, its protein quantity and composition must be maintained through the efficient degradation and resynthesis for proper tissue homeostasis. Life-style behaviors such as increasing physical activity and higher protein diets are front-line treatment strategies to enhance muscle protein remodeling by primarily stimulating protein synthesis rates. However, the muscle of individuals with obesity appears to be resistant to the anabolic action of targeted exercise regimes and protein ingestion when compared to normal-weight adults. This indicates impaired muscle protein remodeling in response to the main anabolic stimuli to human skeletal muscle tissue is contributing to poor muscle health with obesity. Deranged anabolic signaling related to insulin resistance, lipid accumulation, and/or systemic/muscle inflammation are likely at the root of the anabolic resistance of muscle protein synthesis rates with obesity. The purpose of this review is to discuss the impact of protein ingestion and exercise on muscle protein remodeling in people with obesity, and the potential mechanisms underlining anabolic resistance of their muscle

Parents’ Perceptions of the College Experiences of Twice-Exceptional Students with Autism Spectrum Disorder

Students with Autism Spectrum Disorder are accessing college in increasing numbers, and within this group, there is a cohort of academically talented students who can be considered twice-exceptional, or 2e-ASD. While research about college students with ASD is increasing, there is a relative dearth of literature about 2e-ASD college students, and their secondary transition and college experiences. The current study presents the results of individual interviews that were conducted with 10 parents of 2e-ASD college students to explore their perceptions of their children’s experiences, including what things went well and what were problematic areas. Parents described clear and early expectations that the student would attend college and that college provided the student with independence and the chance to be with people who shared similar interests. They described factors that were considered during the college search including the size of the campus and distance from home, and the importance of letting the student take increased responsibility, and if necessary, make and learn from mistakes. The need to focus on executive functioning and social skills was also noted. Implications for families, secondary transition personnel, and vocational rehabilitation counselors are presented