Levels of Ca\u3csub\u3ev\u3c/sub\u3e1.2 L-Type Ca\u3csup\u3e2+\u3c/sup\u3e Channels Peak in the First Two Weeks in Rat Hippocampus Whereas Ca\u3csub\u3ev\u3c/sub\u3e1.3 Channels Steadily Increase through Development

Influx of calcium through voltage-dependent channels regulates processes throughout the nervous system. Specifically, influx through L-type channels plays a variety of roles in early neuronal development and is commonly modulated by G-protein-coupled receptors such as GABAB receptors. Of the four isoforms of L-type channels, only Cav1.2 and Cav1.3 are predominately expressed in the nervous system. Both isoforms are inhibited by the same pharmacological agents, so it has been difficult to determine the role of specific isoforms in physiological processes. In the present study, Western blot analysis and confocal microscopy were utilized to study developmental expression levels and patterns of Cav1.2 and Cav1.3 in the CA1 region of rat hippocampus. Steady-state expression of Cav1.2 predominated during the early neonatal period decreasing by day 12. Steady-state expression of Cav1.3 was low at birth and gradually rose to adult levels by postnatal day 15. In immunohistochemical studies, antibodies against Cav1.2 and Cav1.3 demonstrated the highest intensity of labeling in the proximal dendrites at all ages studied (P1–72). Immunohistochemical studies on one-week-old hippocampi demonstrated significantly more colocalization of GABAB receptors with Cav1.2 than with Cav1.3, suggesting that modulation of L-type calcium current in early development is mediated through Cav1.2 channels

Ways of Being Smart in Engineering: Beliefs, Values, and Introductory Engineering Experiences

Common discourse conveys that to be an engineer, one must be “smart.” Our individual and collective beliefs about what constitutes smart behavior are shaped by our participation in the complex cultural practice of smartness. From the literature, we know that the criteria for being considered “smart” in our educational systems are biased. The emphasis on selecting and retaining only those who are deemed “smart enough” to be engineers perpetuates inequity in undergraduate engineering education. Less is known about what undergraduate students explicitly believe are the different ways of being smart in engineering or how those different ways of being a smart engineer are valued in introductory engineering classrooms. In this study, we explored the common beliefs of undergraduate engineering students regarding what it means to be smart in engineering. We also explored how the students personally valued those ways of being smart versus what they perceived as being valued in introductory engineering classrooms. Through our multi-phase, multi-method approach, we initially qualitatively characterized their beliefs into 11 different ways to be smart in engineering, based on a sample of 36 engineering students enrolled in first-year engineering courses. We then employed quantitative methods to uncover significant differences, with a 95% confidence interval, in six of the 11 ways of being smart between the values personally held by engineering students and what they perceived to be valued in their classrooms. Additionally, we qualitatively found that 1) students described grades as central to their classroom experience, 2) students described the classroom as a context where effortless achievement is associated with being smart, and 3) students described a lack of reward in the classroom for showing initiative and for considerations of social impact or helping others. As engineering educators strive to be more inclusive, it is essential to have a clear understanding and reflect on how students value different ways of being smart in engineering as well as consider how these values are embedded into teaching praxis

Studying Short-Period Comets and Long-Period Comets Detected by WISE/NEOWISE

The Wide-field Infrared Survey Explorer (WISE) mission surveyed the sky in four infrared wavelength bands (3.4, 4.6, 12 and 22 μm) between January 2010 and February 2011. During the mission, WISE serendipitously observed 160 comets, including 21 newly discovered objects. About 89 of the comets observed by WISE displayed a significant dust tail in the 12 and 22 μm (thermal emission) bands, showing a wide range of activity levels and dust morphology. Since the observed objects are a mix of both long-period comets (LPCs) and short-period comets (SPCs), differences in their activity can be used to better understand the thermal evolution that each of these populations has undergone. For the comets that displayed a significant dust tail, we have estimated the sizes and ages of the particles using dynamical models based on the Finson-Probstein method [Finson and Probstein, 1968]. For a selection of 40 comets, we have then compared these models to the data using a novel tail-fitting method that allows the best-fit model to be chosen analytically rather than subjectively. For comets that were observed multiple times by WISE, the particle properties were estimated separately, and then compared. We find that the dust tails of both LPCs and SPCs are primarily comprised of ~mm-cm sized particles, which were the result of emission that occurred several months to several years prior to the observations. The LPCs nearly all have strong emission close to the comet*s perihelion distance, and the SPCs mostly have strong emission close to perihelion, but some have strong emission well before perihelion

An Intervention to Promote Growth Mindset and STEM Self-Efficacy of High School Students: Exploring the Complexity of Beliefs

The marginalization of women in engineering is a persistent problem. The overall goal of our collaborative project was to promote interest and participation in science, technology, engineering, and mathematics (STEM), particularly for high school girls. We took an action research approach with a local high school science teacher to develop, implement, and research the impact of a classroom-based intervention designed to encourage growth mindset and STEM self-efficacy beliefs using mixed methods. We analyzed pre- and postsurvey data collected using a control-treatment design to determine the impact of the intervention on high school boys’ and girls’ self-efficacy and mindset beliefs. We also conducted semi-structured, one-on-one interviews with purposefully selected participants from the treatment group to further explore students’ mindset and STEM self-efficacy beliefs qualitatively. We found that the intervention did result in a statistically significant change towards more growth-oriented beliefs for the high school girls who received the intervention as compared to the control group. We found that the intervention did not result in any statistically significant change in the girls’ self-efficacy beliefs, the boys’ mindset beliefs, or the boys’ self-efficacy beliefs. The qualitative analysis revealed that after receiving the intervention, students held contradictory beliefs about the role of effort and the role of innate ability in STEM achievement. Further, we found that context and gender mattered in how students justified their self-efficacy: boys and girls both expressed the belief that effort would lead to their ability to succeed in science classes, but the girls were less likely than the boys to express the belief that effort would lead to their ability to succeed in the context of a science career. By connecting our findings to broader cultural narratives, we suggest that for the continued success of intervention efforts aimed at promoting a growth mindset and STEM self-efficacy, particularly for girls, such efforts should include opportunities for students to reflect upon and unpack the broader cultural narratives about effort, innate ability, and the gendered stereotypes about STEM ability that inform their beliefs. Finally, from the perspective of a high school science teacher, we also advocate for more representation of women among science teachers and classroom speakers and the importance of explicitly connecting class content and success in classrooms to real-world contexts

NEOWISE: Observations of the Irregular Satellites of Jupiter and Saturn

We present thermal model fits for 11 Jovian and 3 Saturnian irregular satellites based on measurements from the WISE/NEOWISE dataset. Our fits confirm spacecraft-measured diameters for the objects with in situ observations (Himalia and Phoebe) and provide diameters and albedo for 12 previously unmeasured objects, 10 Jovian and 2 Saturnian irregular satellites. The best-fit thermal model beaming parameters are comparable to what is observed for other small bodies in the outer Solar System, while the visible, W1, and W2 albedos trace the taxonomic classifications previously established in the literature. Reflectance properties for the irregular satellites measured are similar to the Jovian Trojan and Hilda Populations, implying common origins.Comment: 17 pages, 3 figures, accepted for publication in Astrophysical Journa

Dimensions of Community Change: How the Community of Sudbury Responded to Industrial Exposures and Cleaned up its Environment

A city in northern Ontario, which has suffered more than a century of pollution from mining, went from being internationally notorious for its pollution to winning awards for its environmental restoration. The inquiry was into the levers of change that led from an awareness of environmental destruction to taking action. Semi-structured interviews were conducted with 60 people from the community, politicians, industry, miners, and academics. The theory-based analysis led to a community-change model that has helped identify the multiple layers of change required for the re-greening of the environment. With reference to the collective impact literature, this city-level case study found that the city has embraced change based upon agreement on an emerging vision, taking advantage of a confluence of timing and events, adopting evidence-based knowledge, building a sense of pride and place, and having a diffuse yet linked leadership. The Sudbury story is helpful for other industrial communities looking to achieve change

A Dynamical Analysis of the Dust Tail of Comet C/1995 O1 (Hale-Bopp) at High Heliocentric Distances

Comet C/1995 O1 (Hale-Bopp) has provided an unprecedented opportunity to observe a bright comet over a wide range of heliocentric distances. We present here Spitzer Space Telescope observations of Hale-Bopp from 2005 and 2008 that show a distinct coma and tail, the presence of which is uncommon given its large heliocentric distance (21.6 AU and 27.2 AU, respectively). The morphology of the dust is compared to dynamical models to understand the activity of the comet. Our analysis shows that the shape of Hale-Bopp's dust tail in these images cannot be explained using the usual Finson-Probstein (solar gravity + solar radiation pressure) dynamical model. Several alternative explanations are explored. The analysis suggests that the most likely cause of the discrepancy is that the dust is being charged by the solar wind, then being affected by the interplanetary magnetic field via the Lorentz force. Though this effect has been explored previously, if correct, this seems to be the first time that the Lorentz force has been required to model a cometary dust tail. The analysis also suggests that Hale-Bopp was actively emitting particles when these images were taken, and the tail characteristics changed between observations.Comment: 23 pages, 10 figures. Accepted to Icarus on 17 March 201

VOEvent Standard for Fast Radio Bursts

Fast radio bursts are a new class of transient radio phenomena currently detected as millisecond radio pulses with very high dispersion measures. As new radio surveys begin searching for FRBs a large population is expected to be detected in real-time, triggering a range of multi-wavelength and multi-messenger telescopes to search for repeating bursts and/or associated emission. Here we propose a method for disseminating FRB triggers using Virtual Observatory Events (VOEvents). This format was developed and is used successfully for transient alerts across the electromagnetic spectrum and for multi-messenger signals such as gravitational waves. In this paper we outline a proposed VOEvent standard for FRBs that includes the essential parameters of the event and where these parameters should be specified within the structure of the event. An additional advantage to the use of VOEvents for FRBs is that the events can automatically be ingested into the FRB Catalogue (FRBCAT) enabling real-time updates for public use. We welcome feedback from the community on the proposed standard outlined below and encourage those interested to join the nascent working group forming around this topic.Comment: 11 pages, 2 figures, parameter definition table in appendi