Search

The paleogeography of Laurentia throughout the Neoproterozoic is critical for reconstructing global paleogeography due to its central position in the supercontinent Rodinia. We develop a new paleomagnetic pole from red siltstones and fine-grained sandstones of the early Neoproterozoic Jacobsville Formation which is now constrained to be ca. 990 Ma in age. High-resolution thermal demagnetization experiments resolve detrital remanent magnetizations held by hematite. These directions were reoriented within siltstone intraclasts and pass intraformational conglomerate tests—giving confidence that the magnetization is detrital and primary. An inclination-corrected mean paleomagnetic pole position for the Jacobsville Formation indicates that Laurentia's motion slowed down significantly following the onset of the Grenvillian orogeny. Prior rapid plate motion associated with closure of the Unimos Ocean between 1,110 and 1,090 Ma transitioned to slow drift of Laurentia across the equator in the late Mesoproterozoic to early Neoproterozoic. We interpret the distinct position of this well-dated pole from those in the Grenville orogen that have been assigned a similar age to indicate that the ages of the poles associated with the Grenville Loop likely need to be revised to be younger due to prolonged exhumation.

Inclination is the angle of a magnetization vector from horizontal. Clastic sedimentary rocks often experience inclination shallowing whereby syn- to post-depositional processes result in flattened detrital remanent magnetizations relative to local geomagnetic field inclinations. The deviation of recorded inclinations from true values presents challenges for reconstructing paleolatitudes. A widespread approach for estimating flattening factors (f) compares the shape of an assemblage of magnetization vectors to that derived from a paleosecular variation model (the elongation/inclination [E/I] method). Few studies exist that compare the results of this statistical approach with empirically determined flattening factors and none in the Proterozoic Eon. In this study, we evaluate inclination shallowing within 1.1 billion-year-old, hematite-bearing red beds of the Cut Face Creek Sandstone that is bounded by lava flows of known inclination. Taking this inclination from the volcanics as the expected direction, we found that detrital hematite remanence is flattened with (Formula presented.) whereas the pigmentary hematite magnetization shares a common mean with the volcanics. Using the pigmentary hematite direction as the expected inclination results in (Formula presented.). These flattening factors are consistent with those estimated through the E/I method (Formula presented.) supporting its application in deep time. However, all methods have significant uncertainty associated with determining the flattening factor. This uncertainty can be incorporated into paleomagnetic poles with the resulting ellipse approximated with a Kent distribution. Rather than seeking to find “the flattening factor,” or assuming a single value, the inherent uncertainty in flattening factors should be recognized and incorporated into paleomagnetic syntheses.

Privacy policies are critical to understanding one’s rights on online platforms, yet few users read them. In this pictorial, we approach this as a systemic issue that ispart a failure of interaction design. We provided a variety of people with printed packets of privacy policies, aimingto tease out this form’s capabilities and limitations as a design interface, to understand people’s perception anduses, and to critically imagine pragmatic revisions and creative alternatives to existing privacy policies.

Although “privacy by design” (PBD)—embedding privacy protections into products during design, rather than retroactively—uses the term “design” to recognize how technical design choices implement and settle policy, design approaches and methodologies are largely absent from PBD conversations. Critical, speculative, and value-centered design approaches can be used to elicit reflections on relevant social values early in product development, and are a natural fit for PBD and necessary to achieve PBD’s goal. Bringing these together, we present a case study using a design workbook of speculative design fictions as a values elicitation tool. Originally used as a reflective tool among a research group, we transformed the workbook into artifacts to share as values elicitation tools in interviews with graduate students training as future technology professionals. We discuss how these design artifacts surface contextual, socially-oriented understandings of privacy, and their potential utility in relationship to other values levers.

We present a set of design fiction proposals related to sensing and tracking technologies, inspired by the 2013 science fiction novel The Circle. By creating design proposals that explore connections between the novel’s imagined world and our present and future realities, we show that we are able to explore, expand, and articulate a range of social, technical, and legal configurations of the future. This paper contributes a set of design fiction proposals and a case study of a design project that uses design fiction inspired by a science fiction text to engage issues of privacy and surveillance. The paper also provides a new approach to creating design fiction, by using science fiction texts as a starting point.

Mechanobiology is a rapidly advancing field, with growing evidence that mechanical signaling plays key roles in health and disease. To accelerate mechanobiology-based drug discovery, novel in vitro systems are needed that enable mechanical perturbation of cells in a format amenable to high throughput screening. Here, both a mechanical stretch device and 192-well silicone flexible linear stretch plate were designed and fabricated to meet high throughput technology needs for cell stretch-based applications. To demonstrate the utility of the stretch plate in automation and screening, cell dispensing, liquid handling, high content imaging, and high throughput sequencing platforms were employed. Using this system, an assay was developed as a biological validation and proof-of-concept readout for screening. A mechano-transcriptional stretch response was characterized using focused gene expression profiling measured by RNA-mediated oligonucleotide Annealing, Selection, and Ligation with Next-Gen sequencing. Using articular chondrocytes, a gene expression signature containing stretch responsive genes relevant to cartilage homeostasis and disease was identified. The possibility for integration of other stretch sensitive cell types (e.g., cardiovascular, airway, bladder, gut, and musculoskeletal), in combination with alternative phenotypic readouts (e.g., protein expression, proliferation, or spatial alignment), broadens the scope of high throughput stretch and allows for wider adoption by the research community. This high throughput mechanical stress device fills an unmet need in phenotypic screening technology to support drug discovery in mechanobiology-based disease areas. [ABSTRACT FROM AUTHOR]

This paper describes and explains details of the design, production and packaging of a counterfunctional device: The Obscura 1C Digital Camera. We further describe a small-scale distribution of Obscura 1C packages into everyday contexts. The paper then reflects on the various types of conceptual, imaginary and firsthand uses made of the Obscura 1C. These include its uses for everyday audiences as a unique camera and as a conceptually usable device. But we also prioritize uses particular to the HCI and design audience. These include using the Obscura 1C to articulate the concepts of inhibitive interfaces, counterfunctionality, and enabling limitations. The Obscura 1C is further used to articulate how abstract ideas can be translated into material forms, to rethink the role of packaging in user studies, and to draw attention to how discursive design objects are packaged and presented.

Genomic sequencing and structural genomics produced a vast amount of sequence and structural data, creating an opportunity for structure-function analysis in silico [Radivojac P, et al. (2013) Nat Methods 10(3):221-227]. Unfortunately, only a few large experimental datasets exist to serve as benchmarks for function-related predictions. Furthermore, currently there are no reliable means to predict the extent of functional similarity among proteins. Here, we quantify structure-function relationships among three phylogenetic branches of the matrix metalloproteinase (MMP) family by comparing their cleavage efficiencies toward an extended set of phage peptide substrates that were selected from ∼ 64 million peptide sequences (i.e., a large unbiased representation of substrate space). The observed second-order rate constants [k(obs)] across the substrate space provide a distance measure of functional similarity among the MMPs. These functional distances directly correlate with MMP phylogenetic distance. There is also a remarkable and near-perfect correlation between the MMP substrate preference and sequence identity of 50-57 discontinuous residues surrounding the catalytic groove. We conclude that these residues represent the specificity-determining positions (SDPs) that allowed for the expansion of MMP proteolytic function during evolution. A transmutation of only a few selected SDPs proximal to the bound substrate peptide, and contributing the most to selectivity among the MMPs, is sufficient to enact a global change in the substrate preference of one MMP to that of another, indicating the potential for the rational and focused redesign of cleavage specificity in MMPs.

This paper presents a set of design studies and discussions investigating new possibilities in designing digital limitations. Focusing on digital photography as a medium, we present design prototypes and experiments including Ultra-Low Resolution Displays, Inaccessible Cameras, and a set of point-and-shoot digital camera variants. Our design work is based on the concept of a counterfunctional thing-a thing that figuratively counters some of its own functionality. We present the concept of counterfunctionality as a way of approaching the design of interactive technology. In conclusion we connect our work with critical discourses surrounding technology and the value of designing limitations. Copyright © 2014 ACM.

The source of tissue turnover during homeostasis or following injury is usually due to proliferation of a small number of resident, lineage-restricted stem cells that have the ability to amplify and differentiate into mature cell types. We are studying vascular regeneration in a chordate model organism, Botryllus schlosseri, and have previously found that following surgical ablation of the extracorporeal vasculature, new tissue will regenerate in a VEGF-dependent process within 48 hrs. Here we use a novel vascular cell lineage tracing methodology to assess regeneration in parabiosed individuals and demonstrate that the source of regenerated vasculature is due to the proliferation of pre-existing vascular resident cells and not a mobile progenitor. We also show that these cells are bi-potential, and can reversibly adopt two fates, that of the newly forming vessels or the differentiated vascular tissue at the terminus of the vasculature, known as ampullae. In addition, we show that pre-existing vascular resident cells differentially express progenitor and differentiated cell markers including the Botryllus homologs of CD133, VEGFR-2, and Cadherin during the regenerative process.