Agnes Scott College

We present the discovery of seven molecular clouds in the radio galaxy B2 0902+34 at redshift z=3.4. These clouds are detected as CO(0-1) absorption features against the bright radio continuum, and spectrally resolved using the Karl G. Jansky Very Large Array (VLA). The velocity dispersion of the individual absorption components ranges from 3-7 km/s, which is similar to values observed for molecular clouds in the Milky Way and nearby galaxies, and imply cloud radii of R~10$^{1-2}$ pc. The absorbing clouds are found in a region of high obscuration inside a 30 kpc wide stellar nebula, as revealed by rest-frame near-ultraviolet imaging performed with the Hubble Space Telescope (HST). The fact that we spectrally resolve molecular clouds at the onset of Cosmic Noon opens prospects for studying cloud chemistry and physics that drive the formation of stars in the Early Universe.

Abstract Although the text of this argument seems to present itself as a tight logical argument, it has what we might call dangling threads. Commentators, beginning in antiquity, have taken these to be invitations to speculation. The result is an array of contradictory analyses about, e.g., the subdivisions of the arguments and, then, how the subdivisions are related to one another, and to the conclusion. In this article, I will offer a new analysis, in which I will distinguish two sub-arguments: one dealing with the principle of motion and one dealing with the principle of becoming; then I will show how the two sub-arguments are related. I will argue that to understand this whole argument, and the way the two sub-arguments fit together, we must assume a conception of motion that differs in important ways from our contemporary conception of motion.

Objective This study describes the prevalence of and relationships between suicide risk, substance use, and help-seeking intentions among college students, as well as knowledge and utilization of the 988 Suicide and Crisis Lifeline. Participants The sample included 1,345 racially diverse college students from a large, urban university in the Southeastern United States. Methods SPSS was used to test correlational relationships between help-seeking intentions and suicide or substance use. Descriptive statistics revealed current rates of suicide risk, substance use, and help-seeking intentions. Results Help-seeking intentions was negatively correlated with suicide risk, suicide behavior, and substance use frequency. Only 20 participants reported using the 988 Lifeline, while 56.6% of participants were unaware of the service. During a crisis, 21.9% of participants reported they would not contact any services. Conclusions These findings suggest the need for crisis training across services and social supports, and greater public awareness of mental health and crisis services.

In an introductory physics problem, students find the depth of a chasm from the time it takes to hear the sound of a dropped boulder hitting the bottom. The standard solution involves a system of two equations with two unknowns, but it turns out that a recursive method will also give the right answer. We analyze this non-traditional approach using iterated maps and determine the conditions under which it converges to the correct solution. Interestingly, the iterative method fails when the well depth is large enough for the rock to reach the speed of sound. Beyond this depth, convergence does not occur due to a series of period-doubling bifurcations, and we show that the iterated map under consideration is conjugate to the logistic map. Perhaps surprisingly, the inclusion of air resistance leads to the same qualitative results. We also demonstrate that the method outlined here can be used to solve other introductory physics problems.

The evolutionary origins of chordates and their diversification into the three major subphyla of tunicates, vertebrates, and cephalochordates pose myriad questions about the genetic and developmental mechanisms underlying this radiation. Studies in non-vertebrate chordates have refined our model of what the ancestral chordate may have looked like, and have revealed the pre-vertebrate origins of key cellular and developmental traits. Work in the major tunicate laboratory model Ciona has benefitted greatly from the emergence of CRISPR/Cas9 techniques for targeted gene disruption. Here we review some of the important findings made possible by CRISPR in Ciona, and present our latest protocols and recommended practices for plasmid-based, tissue-specific CRISPR/Cas9-mediated mutagenesis.

The traditional approach to using videos involves the so-called movie sandwich, which focuses on the use of a single video clip. Based on analogical learning research, we highlight the possible benefits of constructing what we term a video bridge, which consists of two analogous videos that are linked by important themes of similarity and used in tandem to enhance student learning through contrast and comparisons of the videos. In this article, we review research that supports the benefits of analogical learning through video bridges, highlight teaching implications, provide a detailed example of a video bridge with accompanying assignment, and list video resources for management educators to construct their own video bridges.