Skull Flexure from Blast Waves: A Mechanism for Brain Injury with Implications for Helmet Design

Traumatic brain injury [TBI] has become a signature injury of current military conflicts, with debilitating, costly, and long-lasting effects. Although mechanisms by which head impacts cause TBI have been well-researched, the mechanisms by which blasts cause TBI are not understood. From numerical hydrodynamic simulations, we have discovered that non-lethal blasts can induce sufficient skull flexure to generate potentially damaging loads in the brain, even without a head impact. The possibility that this mechanism may contribute to TBI has implications for injury diagnosis and armor design.Comment: version in press, Physical Review Letters; 17 pages, 5 figures (includes supplementary material

Toward a greater understanding of the brain processes underlying handgrip and handgrip fatigue

Handgrip is a ubiquitous human movement that determines how we interact with our environment. It is involved in almost every aspect of daily life (e.g. opening a door, handling cutlery, using tools) and like all human movement, its application is limited by muscle fatigue. However, the supraspinal mechanisms of handgrip and handgrip fatigue are not fully understood despite the importance of this fundamental movement, numerous publications, and its presence as a longstanding research topic. This thesis investigates the brain mechanisms of handgrip and handgrip fatigue using fMRI. It begins with a review of the literature in Chapter one, which evaluates the theories and evidence for central control of handgrip and muscle fatigue as well as describing the rationale to perform the experiments in this thesis. The methodology and analyses are also reviewed to provide rationale for their use and to facilitate the interpretation of subsequent experimental results. In order to understand the supraspinal mechanisms of handgrip and handgrip fatigue it is logical to first understand the most fundamental grip type (power vs. precision) and pattern (static vs. dynamic) by which handgrip can be performed

Supercooled Liquid Water Content Instrument Analysis and Winter 2014 Data with Comparisons to the NASA Icing Remote Sensing System and Pilot Reports

The National Aeronautics and Space Administration (NASA) has developed a system for remotely detecting the hazardous conditions leading to aircraft icing in flight, the NASA Icing Remote Sensing System (NIRSS). Newly developed, weather balloon-borne instruments have been used to obtain in-situ measurements of supercooled liquid water during March 2014 to validate the algorithms used in the NIRSS. A mathematical model and a processing method were developed to analyze the data obtained from the weather balloon soundings. The data from soundings obtained in March 2014 were analyzed and compared to the output from the NIRSS and pilot reports

Qubit Channels Can Require More Than Two Inputs to Achieve Capacity

We give examples of qubit channels that require three input states in order to achieve the Holevo capacity.Comment: RevTex, 5 page, 4 figures

Dominating Sets in Plane Triangulations

In 1996, Matheson and Tarjan conjectured that any n-vertex triangulation with n sufficiently large has a dominating set of size at most n/4. We prove this for graphs of maximum degree 6.Comment: 14 pages, 6 figures; Revised lemmas 6-8, clarified arguments and fixed typos, result unchange