4,701 research outputs found

    Advantages of 3D time-of-flight range imaging cameras in machine vision applications

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    Machine vision using image processing of traditional intensity images is in wide spread use. In many situations environmental conditions or object colours or shades cannot be controlled, leading to difficulties in correctly processing the images and requiring complicated processing algorithms. Many of these complications can be avoided by using range image data, instead of intensity data. This is because range image data represents the physical properties of object location and shape, practically independently of object colour or shading. The advantages of range image processing are presented, along with three example applications that show how robust machine vision results can be obtained with relatively simple range image processing in real-time applications

    Production of ethyl acetate from pyrolysis of lignin model compound guaiacylglycerol-β-guaiacyl using TGA-MS

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    Due to the complex chemical structure of lignin, the fundamental chemistry underlying its pyrolysis behaviour is poorly understood. A detailed knowledge of this chemistry would allow for the construction of detailed predictive chemical kinetic models, which could be used to maximise the efficiency of the pyrolysis process. Lignin is comprised of three monolignols, guaiacyl, p-hydroxyphenyl and syringyl. These are joined together by aryl ether linkages of which β-O-4 is the most common, representing approximately 50% of the linkages found in lignin.[1] In this study, pyrolysis (20oC/minute heating rate) was carried out on a lignin model compound, guaiacylglycerol-β-guaiacyl ether (GGE). GGE is composed of two guaiacyl subunits connected by a β-O-4 linkage, making it broadly representative of the lignin motif and as such an important lignin model compound. A detailed understanding of the thermal degradation of GGE under pyrolysis conditions will provide valuable information of the role of the β-O-4 linkage in lignin. Please click Additional Files below to see the full abstract

    Sprouty1 regulates reversible quiescence of a self-renewing adult muscle stem cell pool during regeneration.

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    Satellite cells are skeletal muscle stem cells capable of self-renewal and differentiation after transplantation, but whether they contribute to endogenous muscle fiber repair has been unclear. The transcription factor Pax7 marks satellite cells and is critical for establishing the adult satellite cell pool. By using a lineage tracing approach, we show that after injury, quiescent adult Pax7(+) cells enter the cell cycle; a subpopulation returns to quiescence to replenish the satellite cell compartment, while others contribute to muscle fiber formation. We demonstrate that Sprouty1 (Spry1), a receptor tyrosine kinase signaling inhibitor, is expressed in quiescent Pax7(+) satellite cells in uninjured muscle, downregulated in proliferating myogenic cells after injury, and reinduced as Pax7(+) cells re-enter quiescence. We show that Spry1 is required for the return to quiescence and homeostasis of the satellite cell pool during repair. Our results therefore define a role for Spry1 in adult muscle stem cell biology and tissue repair

    Model for quantitative tip-enhanced spectroscopy and the extraction of nanoscale-resolved optical constants

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    Near-field infrared spectroscopy by elastic scattering of light from a probe tip resolves optical contrasts in materials at dramatically sub-wavelength scales across a broad energy range, with the demonstrated capacity for chemical identification at the nanoscale. However, current models of probe-sample near-field interactions still cannot provide a sufficiently quantitatively interpretation of measured near-field contrasts, especially in the case of materials supporting strong surface phonons. We present a model of near-field spectroscopy derived from basic principles and verified by finite-element simulations, demonstrating superb predictive agreement both with tunable quantum cascade laser near-field spectroscopy of SiO2_2 thin films and with newly presented nanoscale Fourier transform infrared (nanoFTIR) spectroscopy of crystalline SiC. We discuss the role of probe geometry, field retardation, and surface mode dispersion in shaping the measured near-field response. This treatment enables a route to quantitatively determine nano-resolved optical constants, as we demonstrate by inverting newly presented nanoFTIR spectra of an SiO2_2 thin film into the frequency dependent dielectric function of its mid-infrared optical phonon. Our formalism further enables tip-enhanced spectroscopy as a potent diagnostic tool for quantitative nano-scale spectroscopy.Comment: 19 pages, 9 figure

    Experiments with regulations & markets linking upstream tree plantations with downstream water users

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    Land-use change in upper catchments impact downstream water flows. As trees use large amounts of water the expansion of upstream plantations can substantially reduce water availability to downstream users. There can also be impacts on downstream salinity due to reduced dilution flows. In some jurisdictions afforestation requires the purchase of water rights from downstream holders, while in others it does not, effectively handing the water rights to the upstream landholders. We consider the economic efficiency and equity (profitability and distributional) consequences of upstream land use change in the presence of a water market under alternate property rights regimes and different salinity scenarios.experimental-economics, tree-plantations, environmental-services, urban, irrigation, stock & domestic, water use, land use,

    A Review of Undergraduate Athletic Training Program Entrance Requirements.

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    Purpose: Athletic Training (AT) education is undergoing a major change with the transition to the professional Master’s degree. This evolution provides opportunity for faculty to reassess programmatic requirements. Admissions criteria is the first benchmark set for students and may predict future success. Currently, there is no evidence describing common AT entrance requirements. Objective(s): To determine current practices in AT admissions, establish best practices for developing admissions criteria, and discuss the potential impact of the transition to professional master’s degree on the admissions process. Methods: Design: Cross-Sectional Study. Setting(s): Web-based survey in the fall of 2014. Participant(s): 361 undergraduate program directors received the survey; 117 (32.4%) responded. Intervention(s): The survey consisted of 28 questions: 15 demographics questions and 13 questions relating to: Academic structure (1 question), Program admissions procedures (5 questions), and Selection Process (7 questions). Main Outcome Measure(s): Descriptive statistics were calculated for each variable. Results: There were 117 responses, representing all 10 NATA districts. Ninety-seven percent (n=114) use a secondary admission process. Additionally, the majority of programs (n=94, 89.5%) reported using a combination of GPA data when making admissions decisions (i.e. major GPA and overall GPA). Seventy-two percent (n=84) of programs require clinical experience hours (mean 47.64 ±33.68) prior to admission. Personal attributes were assessed through the use of interviews, essays, and other written documents. Conclusions: There are many factors that may affect a program’s outcome. However, it all begins with the individual program’s admission process. To strengthen the program’s quality, faculty members must review their current admission criteria to ensure each requirement is purposeful, relevant, and non-discriminatory
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