Overview of NASA's programs

An overview of some of NASA's aviation related programs is presented. The areas discussed include: (1) severe storms; (2) clear air turbulence; (3) icing; (4) fog; and (5) landing systems

Let\u27s Tell a Story: Narrative, Constructivism, and Accessibility

I started making video tutorials as a graduate student in library and information science, took a few years off, and started again as a reference librarian at Portland State University. While I always had a sense that video tutorials could be better than they often are, I wasn\u27t really sure exactly what that meant—that is, until I went to remake a few older videos to reflect some changes in the library catalog. How could I communicate those changes in a way that was engaging and helped move the viewer through the video? Then I remembered an old lesson from teaching music theory: tell them a story. For me, telling a story was a foundational aspect of both writing and teaching. So, I thought I would try it out. I was going to tell stories in my videos

Engaging Antiracist Conversations: Foregrounding Twitter Feeds in Library Guides as a Way to Critically Promote Discussions of Racial Justice

Academic librarians have often been hesitant to foreground real-time engagement with social justice in our public facing library guides. The guides, more often than not, serve merely to provide access points to “academic” materials and traditional news sources. Perhaps there is a different path. This chapter suggests that engagement with Twitter can point patrons toward the real conversations happening outside (and sometimes inside) academia that are missed when we rely on traditional sources. The critical engagement with social justice issues such as race and technology, or migrant justice, is happening right in front of our eyes on Twitter. This chapter discusses how adding Twitter feeds to library guides can engage libraries (and our students) in critical conversations around racism and the foregrounding of traditionally marginalized voices. A problem with traditional library guides is that they center the voice and opinion of the librarian curating the guide. Adding in Twitter feeds can complicate this. Adding Twitter feeds from traditionally marginalized voices centers those voices in real time as opposed to centering the voice and authority of the, often white, librarian initially creating the guide. This centering occurs because while the librarian initially chooses which feeds to feature, the feeds are continuously updating in real time. This chapter reflects on why this centering of non-white voices is important, how it engages the counterpublic discourse on Twitter, and how doing so can push us all to be a little more critical, a little more subversive, in our work

In Silico Sequence Optimization for the Reproducible Generation of DNA Structures

Biologically, deoxyribonucleic acid (DNA) molecules have been used for information storage for more than 3 billion years. Today, modern synthesis tools have made it possible to use synthetic DNA molecules as a material for engineering nanoscale structures. These self-assembling structures are capable of both resolutions as fine as 4 angstroms and executing programed dynamic behavior. Numerous approaches for creating structures from DNA have been proposed and validated, however it remains commonplace for engineered systems to exhibit unexpected behaviors such as low formation yields, poor performance, or total failure. It is plausible that at least some of these behaviors arise due to the formation of non-target structures, but how to quantify and avoid these interfering structures remains a critical question. To evaluate the impacts of non-target structures on system behavior, three co-dependent scientific developments were necessary. First, three new optimization criteria for quantifying system quality were proposed and studied. This led to the discovery that relatively small intramolecular structures lead to surprisingly large deviations in system behavior such as reaction kinetics. Second, a new heuristic algorithm for generating high quality systems was developed. This algorithm enabled the experimental characterization of newly generated systems, thus validating the optimization criteria and confirming the finding that almost all kinetic variation can be explained by non-target intramolecular structures. Finally, these studies necessitated the creation of two new software tools; one for analyzing existing DNA systems (the “Device Profiler” software) and another for generating fit DNA systems (the “Sequence Evolver” software). In order to enable these tools to handle the size and complexity of state-of-the-art systems, it was necessary to invent efficient software implementations of the metrics and algorithm. The performance of the software was benchmarked against several alternative tools in use by the DNA nanotechnology community, with the results indicating a marked improvement in system quality over current state-of-the-art methods. Ultimately, the new optimization criteria, heuristic algorithm, and software cooperatively enabled an improved method for generating DNA systems with kinetically uniform behaviors

Generation of DNA Oligomers with Similar Chemical Kinetics via in-silico Optimization

Networks of interacting DNA oligomers are useful for applications such as biomarker detection, targeted drug delivery, information storage, and photonic information processing. However, differences in the chemical kinetics of hybridization reactions, referred to as kinetic dispersion, can be problematic for some applications. Here, it is found that limiting unnecessary stretches of Watson-Crick base pairing, referred to as unnecessary duplexes, can yield exceptionally low kinetic dispersions. Hybridization kinetics can be affected by unnecessary intra-oligomer duplexes containing only 2 base-pairs, and such duplexes explain up to 94% of previously reported kinetic dispersion. As a general design rule, it is recommended that unnecessary intra-oligomer duplexes larger than 2 base-pairs and unnecessary inter-oligomer duplexes larger than 7 base-pairs be avoided. Unnecessary duplexes typically scale exponentially with network size, and nearly all networks contain unnecessary duplexes substantial enough to affect hybridization kinetics. A new method for generating networks which utilizes in-silico optimization to mitigate unnecessary duplexes is proposed and demonstrated to reduce in-vitro kinetic dispersions as much as 96%. The limitations of the new design rule and generation method are evaluated in-silico by creating new oligomers for several designs, including three previously programmed reactions and one previously engineered structure

Two-color resonant four-wave mixing: a tool for double resonance spectroscopy

Two-color resonant four-wave mixing (RFWM) shows great promise in a variety of double-resonance applications in molecular spectroscopy and chemical dynamics. One such application is stimulated emission pumping (SEP), which is a powerful method of characterizing ground-state potential energy surfaces in regions of chemical interest. The authors use time-independent, diagrammatic perturbation theory to identify the resonant terms in the third-order nonlinear susceptibility for each possible scheme by which two-color RFWM can be used for double-resonance spectroscopy. After a spherical tensor analysis they arrive at a signal expression for two-color RFWM that separates the molecular properties from purely laboratory-frame factors. In addition, the spectral response for tuning the DUMP laser in RFWM-SEP is found to be a simple Lorentzian in free-jet experiments. The authors demonstrate the utility of RFWM-SEP and test their theoretical predictions in experiments on jet-cooled transient molecules. In experiments on C{sub 3} they compare the two possible RFWM-SEP processes and show that one is particularly well-suited to the common situation in which the PUMP transition is strong but the DUMP transitions are weak. They obtain RFWM-SEP spectra of the formyl radical, HCO, that probe quasibound vibrational resonances lying above the low threshold for dissociation to H+CO. Varying the polarization of the input beams or PUMP rotational branch produces dramatic effects, in the relative intensities of rotational lines in the RFWM-SEP spectra of HCO; these effects are well-described by their theoretical analysis. Finally, RFWM-SEP spectra of HCO resonances that are homogeneously broadened by dissociation confirm the predicted lineshape and give widths that are in good agreement with those determined via unsaturated fluorescence depletion SEP

Closure Report for Corrective Action Unit 262: Area 25 Septic Systems and Underground Discharge Point, Nevada Test Site, Nevada

This Closure Report (CR) documents the activities undertaken to close Corrective Action Unit (CAU) 262: Area 25 Septic Systems and Underground Discharge Point, in accordance with the Federal Facility Agreement and Consent Order (FFACO) of 1996. Site closure was performed in accordance with the Nevada Division of Environmental Protection (NDEP)-approved Corrective Action Plan (CAP) for CAU 262 (U.S. Department of Energy, National Nuclear Security Administration Nevada Operations Office [NNSA/NV, 2002a]). CAU 262 is located at the Nevada Test Site (NTS) approximately 105 kilometers (65 miles) northwest of Las Vegas, Nevada. CAU 262 consists of the following nine Corrective Action Sites (CASs) located in Area 25 of the NTS: CAS 25-02-06, Underground Storage tank CAS 25-04-06, Septic Systems A and B CAS 25-04-07, Septic System CAS 25-05-03, Leachfield CAS 25-05-05, Leachfield CAS 25-05-06, Leachfield CAS 25-05-08, Radioactive Leachfield CAS 25-05-12, Leachfield CAS 25-51-01, Dry Well

SO AS TO COMPASS THE INTEREST: ARTISAN DRAMATURGY, COPYRIGHT REFORM, AND THE THEATRICAL INSURGENCY OF 1856

In 1856, a change in American copyright law finally gave playwrights control over performances of their work. That change was the culmination of decades of concerted and sustained efforts by a small number of playwrights and their political allies, men who embraced a theatrical aesthetic at odds with antebellum American production practices. I argue that previous scholarship has underestimated the importance of the 1856 law to the development of American theatre. Using a series of case studies, I propose that antebellum theatrical production was guided by a system of artisan dramaturgy. Key to this formulation is the concept of bespoke playwrighting: those who composed antebellum performance texts were more wrights than writers, handicraftsmen and women whose medium was the manuscript rather than the printed text. They drew freely from an extensive public domain created and protected by American copyright law. Published and unpublished plays, novels, songs, poems, current events - all were raw materials for the antebellum dramatist, to be combined, recontextualized, and reimagined. The system of artisan dramaturgy encouraged plays tailored to particular actors, companies, and audiences. These practices, among others, vexed playwrights who resented subjecting their plays to the messy, collaborative undertaking of antebellum American playmaking. I explore how their vision for the theatre drew on a particular understanding of natural rights, one that led them to see copyright as the most effective way to alter the economic conditions of playwriting. I document the largely unexplored legislative history of their efforts, which ultimately interposed statutory law into an art form that had been regulated almost entirely by the common law. The1856 legislation accelerated a process that would ultimately alter the balance of power among the various theatrical collaborators in favor of the playwright, driving greater and greater synergy between dramatic text and performance and ultimately allowing playwrights to supplant the primacy of the actor or manager in shaping performances. By so doing, it also significantly reduced the vibrancy, flexibility, and innovation that had characterized the antebellum American theatre

Closure Report for Corrective Action Unit 143: Area 25 Contaminated Waste Dumps, Nevada Test Site, Nevada

This Closure Report (CR) has been prepared for the Area 25 Contaminated Waste Dumps (CWD), Corrective Action Unit (CAU) 143 in accordance with the Federal Facility Agreement and Consent Order [FFACO] (FFACO, 1996) and the Nevada Division of Environmental Protection (NDEP)-approved Corrective Action Plan (CAP) for CAU 143: Area 25, Contaminated Waste Dumps, Nevada Test Site, Nevada. CAU 143 consists of two Corrective Action Sites (CASs): 25-23-09 CWD No.1, and 25-23-03 CWD No.2. The Area 25 CWDs are historic disposal units within the Area 25 Reactor Maintenance, Assembly, and Disassembly (R-MAD), and Engine Maintenance, Assembly, and Disassembly (E-MAD) compounds located on the Nevada Test Site (NTS). The R-MAD and E-MAD facilities originally supported a portion of the Nuclear Rocket Development Station in Area 25 of the NTS. CWD No.1 CAS 25-23-09 received solid radioactive waste from the R-MAD Compound (East Trestle and West Trench Berms) and 25-23-03 CWD No.2 received solid radioactive waste from the E-MAD Compound (E-MAD Trench)