Teaching and Learning That Takes Place in a Diverse English Classroom Through the Use of Culturally Relevant Pedagogy

As the demographics of the United States continue to diversify, teachers must implement culturally responsive instruction in their classrooms to reach all students. This qualitative case study used the theoretical framework of Ladson-Billings’ culturally relevant pedagogy (CRP) to examine how a White, Advanced Placement English teacher selected class literature, how her class of mostly 12th-grade students of color (one White student) responded to the book Native Son by Richard Wright, how the students saw themselves in the characters, and how they expressed their feelings during class discussions and assignments. The data collection was composed of teacher interviews, interview transcripts, classroom observations during the Native Son unit, student focus groups, and observational field notes. The teacher developed numerous effective teaching approaches for her ethnically and culturally diverse student body, allowing her students to make cultural connections through a variety of literary genres. The teacher felt that she chose culturally responsive literature with great care for her students. Several students believed that the teacher genuinely cared about them and took great measures to select culturally responsive literature that reflected their culture, identity, and life experiences. Still, others felt that the book selections did not represent them or their cultures because there were no authors of Latinx descent. Also, most students expressed frustration with society and what they saw as the perpetuation of systematic racism, societal stereotypes, and inequality in their community and beyond. This study’s findings show implications that underline the value of adolescents perceiving themselves in literature through a positive perspective and the significance of teachers using culturally relevant practices in daily instruction

Spinning Red Clocks in Crowded Fields

Ph.D

A 4 Gyr M-dwarf Gyrochrone from CFHT/MegaPrime Monitoring of the Open Cluster M67

We present stellar rotation periods for late K- and early M-dwarf members of the 4 Gyr old open cluster M67 as calibrators for gyrochronology and tests of stellar spin-down models. Using Gaia EDR3 astrometry for cluster membership and Pan-STARRS (PS1) photometry for binary identification, we build this set of rotation periods from a campaign of monitoring M67 with the Canada-France-Hawaii Telescope's MegaPrime wide field imager. We identify 1807 members of M67, of which 294 are candidate single members with significant rotation period detections. Moreover, we fit a polynomial to the period versus color-derived effective temperature sequence observed in our data. We find that the rotation of very cool dwarfs can be explained by a simple solid-body spin-down between 2.7 and 4 Gyr. We compare this rotational sequence to the predictions of gyrochronological models and find that the best match is Skumanich-like spin-down, P_rot \propto t^0.62, applied to the sequence of Ruprecht 147. This suggests that, for spectral types K7-M0 with near-solar metallicity, once a star resumes spinning down, a simple Skumanich-like is sufficient to describe their rotation evolution, at least through the age of M67. Additionally, for stars in the range M1-M3, our data show that spin-down must have resumed prior to the age of M67, in conflict with predictions of the latest spin-down models.Comment: 21 pages, 16 figures, Accepted for publication by Ap

Inheritance of OCT4 predetermines fate choice in human embryonic stem cells

It is well known that clonal cells can make different fate decisions, but it is unclear whether these decisions are determined during, or before, a cell's own lifetime. Here, we engineered an endogenous fluorescent reporter for the pluripotency factor OCT4 to study the timing of differentiation decisions in human embryonic stem cells. By tracking single-cell OCT4 levels over multiple cell cycle generations, we found that the decision to differentiate is largely determined before the differentiation stimulus is presented and can be predicted by a cell's preexisting OCT4 signaling patterns. We further quantified how maternal OCT4 levels were transmitted to, and distributed between, daughter cells. As mother cells underwent division, newly established OCT4 levels in daughter cells rapidly became more predictive of final OCT4 expression status. These results imply that the choice between developmental cell fates can be largely predetermined at the time of cell birth through inheritance of a pluripotency factor

High-resolution SOFIA/EXES Spectroscopy of SO2 Gas in the Massive Young Stellar Object MonR2 IRS3: Implications for the Sulfur Budget

Stars and planetary system

High-resolution SOFIA/EXES Spectroscopy of SO_2 Gas in the Massive Young Stellar Object MonR2 IRS3: Implications for the Sulfur Budget

Sulfur has been observed to be severely depleted in dense clouds leading to uncertainty in the molecules that contain it and the chemistry behind their evolution. Here, we aim to shed light on the sulfur chemistry in young stellar objects (YSOs) by using high-resolution infrared spectroscopy of absorption by the ν_3 rovibrational band of SO_2 obtained with the Echelon-Cross-Echelle Spectrograph on the Stratospheric Observatory for Infrared Astronomy. Using local thermodynamic equilibrium models we derive physical parameters for the SO_2 gas in the massive YSO MonR2 IRS3. This yields a SO_2/H abundance lower limit of 5.6 ± 0.5 × 10^(−7), or >4% of the cosmic sulfur budget, and an intrinsic line width (Doppler parameter) of b < 3.20 km s^(−1). The small line widths and high temperature (T_(ex) = 234 ± 15 K) locate the gas in a relatively quiescent region near the YSO, presumably in the hot core where ices have evaporated. This sublimation unlocks a volatile sulfur reservoir (e.g., sulfur allotropes as detected abundantly in comet 67P/Churyumov–Gerasimenko), which is followed by SO_2 formation by warm, dense gas-phase chemistry. The narrowness of the lines makes formation of SO_2 from sulfur sputtered off grains in shocks less likely toward MonR2 IRS3