1,430 research outputs found

    Morphometric Analysis of Dinosaur Tracks from Southwest Arkansas

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    Dinosaur trackways were discovered in Cretaceous De Queen Limestone strata in Howard County, Arkansas, in June 2011. Multiple trackways with variably sized tridactyl tracks were exposed in a commercial quarry, suggesting multiple theropod species or adult and juvenile tracks of a single species. Results of morphometric analyses of 32 plaster casts from selected trackways are reported in an effort to identify the specific track-making dinosaurs and differentiate large and small tracks. Track measurements included length and width of each track, the lengths and widths of each digit impression, and the angular spread (divarication) between digit impressions. Twenty-nine plaster casts were of tridactyl theropod tracks whereas three casts were of poorly preserved tracks of a presumed but unknown tetradactyl (and possibly tetrapod) organism. Plaster casts of tridactyl theropod tracks ranged from 0.36 to 0.61 m long and 0.22 to 0.54 m wide. The longest digit impression on each track was the second, or middle, digit (range = 0.15 – 0.35 m long) with total digit divarication ranging from 31 - 57 degrees. The Arkansas track measurements were compared to tracks (Eubrontes glenrosensis Shuler 1935) preserved in the correlative Glen Rose Formation, Texas and attributed to the large Early Cretaceous carnosaur, Acrocanthosaurus atokensis. The E. glenrosensis track measurements from Texas plotted within the Arkansas data range, suggesting affinity of the Arkansas tracks to E. glenrosensis. Relatively poor preservation of tetradactyl tracks precluded morphometric analysis, but visual comparison to known Cretaceous crocodilian tracks is suggestive of affinity to such organisms

    A Polarized Clutter Measurement Technique Based on the Governing Equation for Polarimetric Remote Sensing in the Visible to Near Infrared

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    Polarization adds another dimension to the spatial intensity and spectral information typically acquired in remote sensing. Polarization imparted by surface reflections contains unique and discriminatory signatures which may augment spectral target-detection techniques. While efforts have been made toward quantifying the polarimetric bidirectional reflectance distribution function (pBRDF) responsible for target material polarimetric signatures, little has been done toward developing a description of the polarized background or scene clutter. An approach is presented for measuring the pBRDF of background materials such as vegetation. The governing equation for polarized radiance reaching a sensor aperture is first developed and serves as a basis for understanding outdoor pBRDF measurements, as well as polarimetric remote sensing. The pBRDF measurements are acquired through an imaging technique which enables derivation of the BRDF variability as a function of the ground separation distance (GSD). An image subtraction technique is used to minimize measurement errors resulting from the partially polarized downwelled sky radiance. Quantifying the GSD-dependent BRDF variability is critical for background materials which are typically spatially inhomogeneous. Preliminary results from employing the measurement technique are presented

    A dual-cavity ruby maser for the Ka-band link experiment

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    A 33.68-GHz dual-cavity ruby maser was built to support the Ka-Band Link Experiment (KABLE) conducted with the Mars Observer spacecraft. It has 25 dB of net gain and a 3-dB bandwidth of 85 MHz. Its noise temperature in reference to the cooled feedhorn aperture is 5 K

    Building the Emotionally Learned Negotiator

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    This piece reviews three recent books on the significance of emotion in negotiation and dispute resolution (Fisher & Shapiro: Beyond Reason: Using Emotions as You Negotiate; Peter Ladd: Mediation, Conciliation and Emotion: A Practitioner\u27s Guide for Understanding Emotions in Dispute Resolution; and Lacey Smith: Get It! Street-Smart Negotiation at Work: How Emotions Get You What You Want), situating each work within a theory of practice for emotionally learned negotiators. After discussing the how the appearance of emotional sterility became synonymous with professionalism (and the toll this has taken on professional interaction), the piece sets forth a functional theory of emotion in negotiation based on four elements: emotion as (1) ether, (2) obstacle, (3) episteme, and (4) instrument. To cast emotion as ether (the ether of human experience) is to understand the inevitability of emotional impacts on negotiated exchange. For many, emotion in negotiation is encountered as an obstacle (that which obstructs mechanical application of established negotiating techniques). The more sophisticated negotiator recognizes emotionality as episteme (the medium of insight by which we consult interests and hypothesize about others) - a means for better understanding herself, the people she deals with, and a good deal else about the world. Finally, the emotionally learned negotiator uses emotion not only epistemologically but also instrumentally (as a tool for achieving desired ends), taking affirmative steps to help manage the emotional climate within a negotiation. She uses her emotional skills to mitigate undesired emotions and engender preferred emotions within herself and other participants: to soothe, bolster, win respect, build trust, and encourage creativity. The emotionally learned negotiator thus uses emotions not only as tools of knowing, but as instruments of persuasion. The new series of books on the subject offer strategies by which negotiators can learn to better integrate emotional skills into negotiation, among the most emotionally-charged of professional spheres. While the three books share the central premise that emotionality plays a critical role in the unfolding dynamics of all negotiations, each offers its own primary lesson. Lacey Smith\u27s business-oriented Get It! examines how the emotions of hope and fear can be both tools and obstacles to the interest-based bargaining method we first learned in Roger Fisher\u27s classic, Getting to Yes. Fisher and Shapiro\u27s Beyond Reason takes the Getting to Yes method to the next level of sophistication, providing a taxonomy of core emotional concerns that underlie individual negotiators\u27 behavior, and with it a Seven-Elements - like structure from which to prepare, advance, and overcome emotional obstacles in each negotiating context. Peter Ladd\u27s Mediation, Conciliation and Emotions expands the analysis of emotional content in a negotiation from the individual to the shared experience, exploring the establishment of emotional climates that arise between individuals and offering empirically based counsel for mediators and conciliators about how to help remedy undesirable emotional climates and create emotional climates more conducive to problem-solving. No book has all the answers we need, but each makes a valuable contribution to the field

    A Method of Altering Coronal Plane Prosthetic Foot Stiffness for Studying its Effect on Amputee Gait

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    In an effort to understand the effects of prosthetic foot stiffness on amputee gait and mobility, it is useful to produce prototype prosthetic feet that differ in stiffness. While many commercial prosthetic feet are made out of carbon fiber, the manufacturing process is ill-suited to design experimentation as it is expensive, time consuming and requires tooling modifications to produce design changes. In order to facilitate a study of the effects of coronal plane prosthetic foot stiffness on amputee maneuvering gait, we are manufacturing custom prosthetic feet using a form of additive manufacturing, selective laser sintering (SLS), that was developed at the University of Texas at Austin. We have previously used SLS technology to create functional transtibial prosthetic sockets, ankle-foot orthoses, and prosthetic foot prototypes. To manufacture prosthetic feet with different stiffnesses, we first measured the stiffness profile of a commercially available carbon fiber prosthetic foot on an Instron 3345 (Norwood, MA) in two configurations where the foot was loaded to 114 kg in foot flat at 0° eversion and toe-only at 5° eversion positions. A computer aided design model of an SLS prosthetic foot was developed and adjusted to match the stiffness profile of the carbon fiber foot. Finite element analysis (SolidWorks Corp.; Waltham, MA) was then used to verify that the desired stiffness level was achieved. This process was repeated to create three prosthetic feet with altered coronal plane stiffness profiles (25% greater, 50% greater, and 25% less) while sagittal stiffness was held constant. The prototype feet were fabricated using selective laser sintering in a Vanguard HiQ/HS SLS Machine (3D Systems Corp.; Rock Hill, SC). Finally, the feet were mechanically tested in the same configurations as the carbon fiber foot to confirm that they had the desired stiffness profiles. Prototype feet closely matched the sagittal stiffness of the chosen prosthetic foot while coronal plane stiffnesses were approximately the same, 30% greater and 30% less than the carbon fiber foot. Future work will be to use these feet to observe the influence of coronal plane stiffness on amputee gait

    Students Respond To The Use Of Instructional Technology In The Accounting Information Systems Classroom

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    A SERVQUAL-inspired instrument measured students’ satisfaction with technology tools used in AIS classrooms; 151 students in six schools participated.  Student in-class computer activities generated the highest satisfaction among students, live software demonstration the least.  Satisfaction varied little by gender or age group.  Student in-class computer activities showed the most reaction of satisfaction to usage rates, and in all cases greater usage led to higher satisfaction.  In some instances, the satisfaction score for a question differed across technology groups, but these differences are not generalizable.  Factor analysis largely supports the a priori loading of satisfaction items into five SERVQUAL dimension

    Alter E(c)o

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    Alter E(c)o is a series of three large-scale sculptures that represent a futuristic, fictional, dystopic landscape. Each individual piece mimics land formations observed in the natural world. The use of synthetic and industrial materials is intended to be a bizarre depiction of telluric matter in millions of years to come. Through size and material, these fictional edifices are meant to allude to the fact that we can be the creators of our existence

    Tunable Visible and Near-IR Photoactivation of Light-Responsive Compounds by Using Fluorophores as Light-Capturing Antennas

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    Although the corrin ring of vitamin B12 is unable to efficiently absorb light beyond 550 nm, it is shown that commercially available fluorophores can be used as antennas to capture long-wavelength light to promote scission of the Co-C bond at wavelengths up to 800 nm. The ability to control the molecular properties of bioactive species with long visible and near-IR light has implications for drug delivery, nanotechnology, and the spatiotemporal control of cellular behavior
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