Sapping Features of the Colorado Plateau: a Comparative Planetary Geology Field Guide

This book is an attempt to determine geomorphic criteria to be used to distinguish between channels formed predominantly by sapping and seepage erosion and those formed principally by surface runoff processes. The geologic nature of the Colorado Plateau has resulted in geomorphic features that show similarities to some areas on Mars, especially certain valley networks within thick sandstone formations. Where spring sapping is an effective process, the valleys that develop are unique in terms of their morphology and network pattern

Externalizing Normativity in Design Reviews: Inscribing Design Values in Designed Artifacts

The design community has discussed issues of ethics and values for decades, but less attention has been paid to the question of how an ethical sensibility might be developed or taken on by design students. In this analysis, we explore how normative concerns emerge through the process of design reviews—where a developing designer’s normative infrastructure is engaged with the artifact they are designing. We focused on the normative concerns that were foregrounded by two undergraduate and two graduate industrial design students across a series of five design reviews, addressing the possible relationship between the emergence of normative concerns and the inscription of norms in the final designed artifact. We used several critical qualitative techniques, including sequence analysis and meaning reconstruction to locate areas where normative concerns were addressed. Normative concerns only arose in explicit form in the earliest review sessions on the graduate level, if they were going to arise at all, and end-user research appeared to be the primary mechanism for introducing norms into the design process. Neither instructor actively engaged or foregrounded the normative infrastructure of the design students, and all of the normative concerns discussed in the four cases were brought to the conversation by students. Implications for including awareness of normative concerns as part of a student’s developing design character are considered as part of a systemic approach to ethics and values in design education

Higher order thinking in design reviews

In this study we have grappled with how higher order thinking emerges in early stage design reviews, using an undergraduate dyadic review and a graduate review in a small group setting. Narratives, gambits and justifications emerged through a content analysis as forms of higher order thinking common in the reviews. We then mapped these reviews onto common frames of reference employed by teachers and students. Results depicted stark differences in the linguistic routines of the two teachers and two different sets of students. Each focused their higher order thinking from a primarily different frame of reference. Conclusions relate to opportunistic teaching strategies and the instructional tensions that the design review poses as a method for teaching the linguistic routines of the design review to early stage designers

Red-Cockaded Woodpeckers vs Rat Snakes: The Effectiveness of the Resin Barrier

Red-cockaded Woodpeckers (Picoides borealis) excavate resin wells in the immediate vicinity of roost and nest cavity entrances. Resin wells are worked regularly, resulting in a copious and persistent resin flow that coats the tree trunk, especially below cavity entrances. Red-cockaded Woodpeckers also scale loose bark from cavity trees and closely adjacent trees. These two behaviors result in smooth, sticky surfaces surrounding cavity entrances. Climbing experiments on cavity, scaled, and control trees using rat snakes (Elaphe obsoleta) demonstrate that these behaviors produce a resinous barrier that is highly effective in preventing predatory snakes from gaining access to active Red-cockaded Woodpecker cavities

Experimental Reintroduction of Red-Cockaded Woodpeckers

The Red-cockaded Woodpecker (Picoides borealis) is an endangered species endemic to the pine forests of the southeastern United States (Jackson 1971). Deforestation and habitat alteration have severely affected Red-cockaded Woodpecker populations; current populations are isolated and most are declining (Jackson 1971, Lennartz et al. 1983, Conner and Rudolph 1989, Costa and Escano 1989). The species has been extirpated from significant areas of suitable or potentially suitable habitat

Introduction to the Student Design Case SLAM

At the 2016 Association for Educational Communications and Technology Convention in Las Vegas, the IJDL editorial team hosted a Student Design Case SLAM. The focus of the one-day workshop was to engage graduate students in writing a publishable design case. Nine graduate students participated in the Design Case SLAM. Each graduate student brought the beginnings of a design case. Students were assigned to groups of three and assigned to an editor. Editors provided design case prompts and students completed free writing exercises which included feedback from the editor and group members

The influence of microRNAs and poly(A) tail length on endogenous mRNA–protein complexes

Background: All mRNAs are bound in vivo by proteins to form mRNA-protein complexes (mRNPs), but changes in the composition of mRNPs during posttranscriptional regulation remain largely unexplored. Here, we have analyzed, on a transcriptome-wide scale, how microRNA-mediated repression modulates the associations of the core mRNP components eIF4E, eIF4G, and PABP and of the decay factor DDX6 in human cells. Results: Despite the transient nature of repressed intermediates, we detect significant changes in mRNP composition, marked by dissociation of eIF4G and PABP, and by recruitment of DDX6. Furthermore, although poly(A)-tail length has been considered critical in post-transcriptional regulation, differences in steady-state tail length explain little of the variation in either PABP association or mRNP organization more generally. Instead, relative occupancy of core components correlates best with gene expression. Conclusions: These results indicate that posttranscriptional regulatory factors, such as microRNAs, influence the associations of PABP and other core factors, and do so without substantially affecting steady-state tail length.National Institutes of Health (U.S.) (Grant K99GM102319)National Institutes of Health (U.S.) (Grant T32GM007753)National Institutes of Health (U.S.) (Grant R01GM067031)National Institutes of Health (U.S.) (Grant R35GM118135)Natural Sciences and Engineering Research Council of Canada (Discovery Grant

Quantifying Robotic Swarm Coverage

In the field of swarm robotics, the design and implementation of spatial density control laws has received much attention, with less emphasis being placed on performance evaluation. This work fills that gap by introducing an error metric that provides a quantitative measure of coverage for use with any control scheme. The proposed error metric is continuously sensitive to changes in the swarm distribution, unlike commonly used discretization methods. We analyze the theoretical and computational properties of the error metric and propose two benchmarks to which error metric values can be compared. The first uses the realizable extrema of the error metric to compute the relative error of an observed swarm distribution. We also show that the error metric extrema can be used to help choose the swarm size and effective radius of each robot required to achieve a desired level of coverage. The second benchmark compares the observed distribution of error metric values to the probability density function of the error metric when robot positions are randomly sampled from the target distribution. We demonstrate the utility of this benchmark in assessing the performance of stochastic control algorithms. We prove that the error metric obeys a central limit theorem, develop a streamlined method for performing computations, and place the standard statistical tests used here on a firm theoretical footing. We provide rigorous theoretical development, computational methodologies, numerical examples, and MATLAB code for both benchmarks.Comment: To appear in Springer series Lecture Notes in Electrical Engineering (LNEE). This book contribution is an extension of our ICINCO 2018 conference paper arXiv:1806.02488. 27 pages, 8 figures, 2 table

Process for Making Single-Domain Magnetite Crystals

A process for making chemically pure, single-domain magnetite crystals substantially free of structural defects has been invented as a byproduct of research into the origin of globules in a meteorite found in Antarctica and believed to have originated on Mars. The globules in the meteorite comprise layers of mixed (Mg, Fe, and Ca) carbonates, magnetite, and iron sulfides. Since the discovery of the meteorite was announced in August 1996, scientists have debated whether the globules are of biological origin or were formed from inorganic materials by processes that could have taken place on Mars. While the research that led to the present invention has not provided a definitive conclusion concerning the origin of the globules, it has shown that globules of a different but related chemically layered structure can be grown from inorganic ingredients in a multistep precipitation process. As described in more detail below, the present invention comprises the multistep precipitation process plus a subsequent heat treatment. The multistep precipitation process was demonstrated in a laboratory experiment on the growth of submicron ankerite crystals, overgrown by submicron siderite and pyrite crystals, overgrown by submicron magnesite crystals, overgrown by submicron siderite and pyrite. In each step, chloride salts of appropriate cations (Ca, Fe, and Mg) were dissolved in deoxygenated, CO2- saturated water. NaHCO3 was added as a pH buffer while CO2 was passed continuously through the solution. A 15-mL aliquot of the resulting solution was transferred into each of several 20 mL, poly(tetrafluoroethylene)-lined hydrothermal pressure vessels. The vessels were closed in a CO2 atmosphere, then transferred into an oven at a temperature of 150 C. After a predetermined time, the hydrothermal vessels were removed from the oven and quenched in a freezer. Supernatant solutions were decanted, and carbonate precipitates were washed free of soluble salts by repeated decantations with deionized water