A Human Subject Evaluation of Airport Surface Situational Awareness Using Prototypical Flight Deck Electronic Taxi Chart Displays

The advent of Instrument Landing Systems has allowed aircraft to safely takeoff and land in low visibility conditions. However, the lack of a means by which pilots can safely navigate on the ground in poor visibility conditions has been the cause of many runway incursions and several fatal aircraft accidents. Currently flight crews use paper chart depictions of the airport surface and out-the-window visual cues to navigate on the surface. In addition they can be provided some feedback about their position on the surface from ATC. In clear, daylight environmental conditions flight crews can correlate airport features and navigation signs from the out-the-window view with the chart features to maintain airport surface situational awareness. In conditions of fog and darkness however, out-the-window cues are less available and it becomes a difficult task for flight crews to maintain situational awareness. Low visibility conditions also prevent ATC from tracking aircraft position on the airport surface from the tower

Fifth Graders as App Designers

Instructional designers are increasingly considering how to include students as participants in the design of instructional technologies. This study provides a lens into participatory design with students by examining how students conceptualized learning applications in science, technology, engineering, and mathematics (STEM) by designing paper prototypes of a learning application related to circuits and electricity. Eighty-nine fifth grade students, including students with learning disabilities and English language learners, participated in this study. Findings of this study indicated that all students conceptualized learning applications as a game and built scaffolds into the gameplay to encourage both content mastery and advancement in the game. Each of the paper prototypes that the students developed provided opportunities for progressive complexity of gameplay related to electricity and circuits as well as options for customization and building background knowledge. Finally, this article identifies implications of these results and considerations for future research. © 2013 ISTE

\u3ci\u3eDrosophila\u3c/i\u3e Muller F Elements Maintain a Distinct Set of Genomic Properties Over 40 Million Years of Evolution

The Muller F element (4.2 Mb, ~80 protein-coding genes) is an unusual autosome of Drosophila melanogaster; it is mostly heterochromatic with a low recombination rate. To investigate how these properties impact the evolution of repeats and genes, we manually improved the sequence and annotated the genes on the D. erecta, D. mojavensis, and D. grimshawi F elements and euchromatic domains from the Muller D element. We find that F elements have greater transposon density (25–50%) than euchromatic reference regions (3–11%). Among the F elements, D. grimshawi has the lowest transposon density (particularly DINE-1: 2% vs. 11–27%). F element genes have larger coding spans, more coding exons, larger introns, and lower codon bias. Comparison of the Effective Number of Codons with the Codon Adaptation Index shows that, in contrast to the other species, codon bias in D. grimshawi F element genes can be attributed primarily to selection instead of mutational biases, suggesting that density and types of transposons affect the degree of local heterochromatin formation. F element genes have lower estimated DNA melting temperatures than D element genes, potentially facilitating transcription through heterochromatin. Most F element genes (~90%) have remained on that element, but the F element has smaller syntenic blocks than genome averages (3.4–3.6 vs. 8.4–8.8 genes per block), indicating greater rates of inversion despite lower rates of recombination. Overall, the F element has maintained characteristics that are distinct from other autosomes in the Drosophila lineage, illuminating the constraints imposed by a heterochromatic milieu