Cosmic visions: bridging science and art

Since the dawn of recorded history, stargazing has shaped—and been shaped by—our understanding of the universe and the place of humans within it. Though we tend to conceptualize art and science as separate spheres, the observation of the heavens has always been interwoven with culture, and artists and astronomers continue to draw inspiration from one another even today. The authors of this paper, over the past few years, have developed and team-taught an interdisciplinary course titled Cosmic Visions: The Science of Astronomy and the Arts. Our course traces the shared, often symbiotic, history of these two ways of knowing, combining scientific instruction with examination of art in a range of genres and traditions, including visual art, music, and theater. Each week students engage in discussions, listen to lectures, and consider readings related to both the science of astronomy and the role of celestial objects in literature and the arts. A midterm and a final exam test students’ mastery of the science, while short essays on works of art and literature challenge them to think about how our changing understanding of heavenly bodies intersects with changing beliefs about humanity. The course culminates in an art project in which students express their own vision of the cosmos and our place within it. What happens when students employ humanistic modes of analysis in company with scientific ones? How does artistic expression change students’ apprehension of scientific concepts? This short essay offers preliminary answers to these deep pedagogical questions.Published versio

Celebrating success at Fernald

Restoration of the Fernald Environmental Management Project is now moving from the environmental investigation stage to real, tangible remediation progress. Using a variety of programmatic innovations, DOE and FERMCO continue to strengthen an effective partnership that supports a mutually-developed mission of safe, least-cost, earliest final remediation of the Fernald Site while complying with all applicable DOE Orders, regulatory requirements and commitments and addressing the concerns of the many stakeholders who have an interest in how remediation at Fernald progresses. The progress that is occurring at Fernald is testimony to a productive DOE/FERMCO partnership that will continue to be an essential part of the difficult environmental restoration task at this site

Influence of Dynamic Ozone Dry Deposition on Ozone Pollution

Identifying the contributions of chemistry and transport to observed ozone pollution using regional-to-global models relies on accurate representation of ozone dry deposition. We use a recently developed configuration of the NOAA GFDL chemistry-climate model - in which the atmosphere and land are coupled through dry deposition-to investigate the influence of ozone dry deposition on ozone pollution over northern midlatitudes. In our model, deposition pathways are tied to dynamic terrestrial processes, such as photosynthesis and water cycling through the canopy and soil. Small increases in winter deposition due to more process-based representation of snow and deposition to surfaces reduce hemispheric-scale ozone throughout the lower troposphere by 5-12 ppb, improving agreement with observations relative to a simulation with the standard configuration for ozone dry deposition. Declining snow cover by the end of the 21st-century tempers the previously identified influence of rising methane on winter ozone. Dynamic dry deposition changes summer surface ozone by -4 to +7 ppb. While previous studies emphasize the importance of uptake by plant stomata, new diagnostic tracking of depositional pathways reveals a widespread impact of nonstomatal deposition on ozone pollution. Daily variability in both stomatal and nonstomatal deposition contribute to daily variability in ozone pollution. Twenty-first century changes in summer deposition result from a balance among changes in individual pathways, reflecting differing responses to both high carbon dioxide (through plant physiology versus biomass accumulation) and water availability. Our findings highlight a need for constraints on the processes driving ozone dry deposition to test representation in regional-to-global models.Peer reviewe

Ab initio study of the beta$-tin->Imma->sh phase transitions in silicon and germanium

We have investigated the structural sequence of the high-pressure phases of silicon and germanium. We have focussed on the cd->beta-tin->Imma->sh phase transitions. We have used the plane-wave pseudopotential approach to the density-functional theory implemented within the Vienna ab-initio simulation package (VASP). We have determined the equilibrium properties of each structure and the values of the critical parameters including a hysteresis effect at the phase transitions. The order of the phase transitions has been obtained alternatively from the pressure dependence of the enthalpy and of the internal structure parameters. The commonly used tangent construction is shown to be very unreliable. Our calculations identify a first-order phase transition from the cd to the beta-tin and from the Imma to the sh phase, and they indicate the possibility of a second-order phase-transition from the beta-tin to the Imma phase. Finally, we have derived the enthalpy barriers between the phases.Comment: 12 pages, 16 figure

IMPACT: The Journal of the Center for Interdisciplinary Teaching and Learning. Volume 10, Issue 2, Summer 2021

Impact: The Journal of the Center for Interdisciplinary Teaching & Learning is a peer-reviewed, biannual online journal that publishes scholarly and creative non-fiction essays about the theory, practice, and assessment of interdisciplinary education. Impact is produced by the Center for Interdisciplinary Teaching & Learning at Boston University College of General Studies. Impact accepts submissions throughout the year and publishes issues in February and July. Please submit your essays for consideration at https:// citl.submittable.com/submit. Impact provides free and open access to all of its research publications. There is no charge to authors for publication, and the journal abides by a CC-BY license. Authors published in Impact retain copyright on their articles, except for any third-party images and other materials added by Impact, which are subject to copyright of their respective owners. Authors are therefore free to disseminate and re-publish their articles, subject to any requirements of third-party copyright owners and subject to the original publication being fully cited. Visitors may download and forward articles subject to the citation requirements; all copyright notices must be displayed. If readers want to search by journal subject they might use these words: education, graduate, undergraduate, interdisciplinary, disciplines, curriculum, higher education.The theme of this issue is interdisciplinary approaches to, or including, the sciences. STEM disciplines like chemistry, biology, physics, computer science, and math are often taught as separate and distinct from the humanities. The concept of STEAM (STEM + Arts) has attempted to make STEM subjects more interdisciplinary, allowing students to interact with the material from different perspectives. The essays in this issue explore unique ways to design and implement interdisciplinary curricula that combine sciences and humanities/arts

Variability in Tropospheric Oxidation from Polluted to Remote Regions

Tropospheric oxidation modulates pollution chemistry and greenhouse gas lifetimes. The hydroxyl radical (OH) is the primary oxidant and the main sink for methane, the second-most influential anthropogenic contributor to climate change. OH is produced following the photolysis of ozone, an oxidant, respiratory irritant and greenhouse gas. Trends in methane or ozone are frequently attributed to their sources, but sink-driven variability is less often considered. I investigate the influence of fluctuations in turbulent loss to the Earth’s surface, also known as deposition, on tropospheric ozone concentrations and chemistry over the relatively polluted eastern United States. I use idealized sensitivity simulations with the global chemistry-climate model AM3 to demonstrate that coherent shifts in deposition, on the order recently observed at a long-term measurement site, affect surface ozone concentrations as much as decreases in its precursor emissions have over the past decade. I conclude that a sub-regional deposition measurement network is needed to confidently attribute trends in tropospheric ozone. Next, I turn to the remote marine troposphere to evaluate two theoretical proxies for variability in the methane sink, OH, with observations from the NASA Atmospheric Tomography (ATom) aircraft campaign. The low concentration and short lifetime of OH preclude the development of a representative measurement network to track its fluctuations in space and time. This dearth of constraints has led to discrepancies in the methane lifetime across models that project atmospheric composition and climate. Observational and modeling studies suggest that few processes control OH fluctuations in relatively clean air masses, and the short OH lifetime implies that it is at steady-state (total production is equal to loss). I leverage this chemistry by evaluating a convolution of OH drivers, OH production scaled by the lifetime of OH against its sink with carbon monoxide, as a potential “steady-state” proxy. I also assess the predictive skill of formaldehyde (HCHO), an intermediate product of the methane and OH reaction. I find that both proxies broadly reflect OH on sub-hemispheric scales (2 km altitude by 20° zonal bins) relative to existing, well-mixed proxies that capture, at best, hemispheric OH variability. HCHO is produced following methane loss by reaction with OH and reflects the insolation influence on OH, while the steady-state proxy demonstrates a stronger relationship with OH and offers insight into its sensitivity to a wider array of drivers. Few components—water vapor, nitric oxide, and the photolysis rate of ozone to singlet-d atomic oxygen—dominate steady-state proxy variance in most regions of the remote troposphere, with water vapor controlling the largest spatial extent. Current satellite instruments measure water vapor directly, and other retrievals like nitrogen dioxide columns or aerosol optical depth or could be used to infer nitric acid or the rate of ozone photolysis. Thus satellite observations may be used to derive a steady-state proxy product to infer OH variability and sensitivity in the near-term. HCHO is also retrieved from satellite instruments, and an OH product using satellite-observed HCHO columns is already in development. The relatively high fluctuation frequency of HCHO or the steady-state proxy advances our insight into the connection between OH and its drivers. The observed steady-state proxy demonstrates a widespread sensitivity to water vapor along the ATom flight tracks, and I conclude that an improved and consistent representation of the water vapor distribution is a necessary step in constraining the methane lifetime across global chemistry-climate models