Gordian Distance and Complete Alexander Neighbors

We call a knot K a complete Alexander neighbor if every possible Alexander polynomial is realized by a knot one crossing change away from K. It is unknown whether there exists a complete Alexander neighbor with nontrivial Alexander polynomial. We eliminate infinite families of knots with nontrivial Alexander polynomial from having this property and discuss possible strategies for unresolved cases. Additionally, we use a condition on determinants of knots one crossing change away from unknotting number one knots to improve KnotInfo’s unknotting number data on 11 and 12 crossing knots. Lickorish introduced an obstruction to unknotting number one, which proves the same result. However, we show that Lickorish’s obstruction does not subsume the obstruction coming from the condition on determinants. Adviser: Professor Mark Brittenham and Professor Alex Zupa

TBI-Apps.com: Teaching Caregivers How to Use Mobile Applications as Compensatory Cognitive Aids for Traumatic Brain Injury

Long-term cognitive deficits resulting from traumatic brain injury (TBI) can profoundly impact a person’s role competence and ability to perform daily activities (AOTA, 2014a). Mobile technologies, including smartphones and tablets, have shown potential as effective compensatory aids for memory and executive functioning in individuals with TBI (Waite, 2012). A website was created to provide caregivers tools to independently select, program, and use Apple iOS devices with TBI survivors. The website featured five tutorials for iOS applications, one tutorial for an iOS accessibility feature, and tips for teaching application use to individuals with TBI. It also included general information on the effects of TBI and ways iOS devices might be adapted for TBI survivors. The website was piloted with five people to assess its effectiveness. Piloters completed a quiz on website content and provided feedback and suggestions for expansion. Resources that encourage using everyday technology to improve the match between a person’s abilities, the environment, and occupational demands may help individuals with TBI increase occupational engagement and performance

Expanders and Property A

We give a cohomological characterisation of expander graphs, and use it to give a direct proof that expander graphs do not have Yu's property A

Postcard Memories: an interactive tablet application for elders with early-stage dementia

In this demonstration, we present ‘Postcard Memories’, an interactive tablet application to create a social space for elders with early stage dementia. The touchscreen tablet application encourages people to create, organize, and send digital postcards that combine photographs and short text with audio and video. Users can send digital or print postcards to family, friends, and caregivers to encourage memory recall and facilitate social interaction. Results from a mixed method user study indicate that people find the interaction with the application enjoyable and meaningful

A comparative study of experimental configurations in synchrotron pair distribution function

The identification and quantification of amorphous components and nanocrystalline phases with very small crystal sizes, smaller than ~3 nm, within samples containing crystalline phases is very challenging. However, this is important as there are several types of systems that contain these matrices: building materials, glass-ceramics, some alloys, etc. The total scattering synchrotron pair distribution function (PDF) can be used to characterize the local atomic order of the nanocrystalline components and to carry out quantitative analyses in complex mixtures. Although the resolution in momentum transfer space has been widely discussed, the resolution in the interatomic distance space has not been discussed to the best of our knowledge. Here, we report synchrotron PDF data collected at three beamlines in different experimental configurations and X-ray detectors. We not only discuss the effect of the resolution in Q-space, Qmax ins of the recorded data and Qmax of the processed data, but we also discuss the resolution in the interatomic distance (real) space. A thorough study of single-phase crystalline nickel used as standard was carried out. Then, selected cement-related samples including anhydrous tricalcium and dicalcium silicates, and pastes derived from the hydration of tricalcium silicate and ye’elimite with bassanite were analyzed.This work is part of the PhD of Mr. Jesus D. Zea-Garcia. This work was supported by Spanish MINECO and FEDER [BIA2017-82391-R research project and I3 [IEDI-2016-0079] program]

A Mixed-Methods Analysis of the Educational Needs of Employers and Non-English Speaking Workers in Arboriculture

Arboricultural employers and non-English speaking workers were surveyed to acquire information about their outreach educational needs. Results suggest that language barriers sometimes reduce job performance and threaten worker safety and relationships. Respondents stated that employee performance would improve if workers received English language and cultural training. Method of education mattered, with face-to-face learner and educator contact as the preferred method. It is recommended that arboriculture employers and outreach educators provide English language and cultural outreach education opportunities to arboriculture workers whose first language is not English, then follow this with arboriculture training and information (such as pesticide safety)