115,398 research outputs found

    Real-Time Non-Intrusive Assessment of Viewing Distance During Computer Use

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    Purpose: To develop and test the sensitivity of an ultrasound-based sensor to assess the viewing distance of visual display terminals operators in real-time conditions. Methods: A modified ultrasound sensor was attached to a computer display to assess viewing distance in real time. Sensor functionality was tested on a sample of 20 healthy participants while they conducted four 10-minute randomly presented typical computer tasks (a match-three puzzle game, a video documentary, a task requiring participants to complete a series of sentences, and a predefined internet search). Results: The ultrasound sensor offered good measurement repeatability. Game, text completion, and web search tasks were conducted at shorter viewing distances (54.4 cm [95% CI 51.3-57.5 cm], 54.5 cm [95% CI 51.1-58.0 cm], and 54.5 cm [95% CI 51.4-57.7 cm], respectively) than the video task (62.3 cm [95% CI 58.9-65.7 cm]). Statistically significant differences were found between the video task and the other three tasks (all p < 0.05). Range of viewing distances (from 22 to 27 cm) was similar for all tasks (F = 0.996; p = 0.413). Conclusions: Real-time assessment of the viewing distance of computer users with a non-intrusive ultrasonic device disclosed a task-dependent pattern. (C) 2016 American Academy of OptometryPostprint (author's final draft

    Report of the SNOMS Project 2006 to 2012, SNOMS SWIRE NOCS Ocean Monitoring System. Part 1: Narrative description

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    The ocean plays a major role in controlling the concentration of carbon dioxide (CO2) in the atmosphere. Increasing concentrations of CO2 in the atmosphere are a threat to the stability of the earth’s climate. A better understanding of the controlling role of the ocean will improve predictions of likely future changes in climate and the impact of the uptake of CO2 itself on marine eco-systems caused by the associated acidification of the ocean waters. The SNOMS Project (SWIRE NOCS Ocean Monitoring System) is a ground breaking joint research project supported by the Swire Group Trust, the Swire Educational Trust, the China Navigation Company (CNCo) and the Natural Environment Research Council. It collects high quality data on concentrations of CO2 in the surface layer of the ocean. It contributes to the international effort to better quantify (and understand the driving processes controlling) the exchanges of CO2 between the ocean and the atmosphere. In 2006 and 2007 a system that could be used on a commercial ship to provide data over periods of several months with only limited maintenance by the ships crew was designed and assembled by NOCS. The system was fitted to the CNCo ship the MV Pacific Celebes in May 2007. The onboard system was supported by web pages that monitored the progress of the ship and the functioning of the data collection system. To support the flow of data from the ship to the archiving of the data at the Carbon Dioxide Information Analysis Center (CDIAC in the USA) data processing procedures were developed for the quality control and systematic handling of the data. Data from samples of seawater collected by the ships crew and analysed in NOC (730 samples) have been used to confirm the consistency of the data from the automated measurement system on the ship. To examine the data collected between 2007 and 2012 the movements of the ship are divided into 16 voyages. Initially The Celebes traded on a route circum-navigating the globe via the Panama and Suez Canals. In 2009 the route shifted to one between Australia and New Zealand to USA and Canada. Analysis of the data is an on going process. It has demonstrated that the system produces reliable data. Data are capable of improving existing estimates of seasonal variability. The work has improved knowledge of gas exchange processes. Data from the crew-collected-samples are helping improve our ability to estimate alkalinity in different areas. This helps with the study of ocean acidification. Data from the 9 round trips in the Pacific are currently being examined along with data made available by the NOAA-PMEL laboratory forming time series from 2004 to 2012. The data from the Pacific route are of considerable interest. One reason is that the data monitors variations in the fluxes of CO2 associated with the current that flows westwards along the equator. This is one of the major natural sources of CO2 from the ocean into the atmosphere

    ChemMatters: Special Issue on NASA's EOS Aura Mission (Sept. 2002)

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    : This ChemMAtters issue features the human side of NASA’s Aura mission with five articles that include interviews with Aura scientists and engineers. ChemMatters is a quarterly publication of the American Chemical Society (ACS) geared to a high school audience. The magazine is designed and written to demystify everyday chemistry. This special edition is the second of four special issues that focussed on atmospheric chemistry and the Aura mission. Each story features one member of the Aura team and their role in the mission as well as their interests outside of science and engineering. The pull-out poster in the center of the magazine includes stories from the countdown by technicians and engineers building the spacecraft and it's instruments. A teacher's guide is also available for this issue. Educational levels: High school

    Fine-Scale Plant Species Identification in a Poor Fen and Integration of Techniques and Instrumentation in a Classroom Setting

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    Refining carbon flux measurements in the carbon cycle is an ongoing challenge. This study attempted to identify plant species in Sallie’s Fen, a nutrient-poor fen in Barrington, New Hampshire, at a fine scale in order to better model and understand carbon exchange between plants and the atmosphere in this type of ecosystem. A protocol for estimating percent cover of species in plots via ground measurements was developed. The next stage of this project was to compare these measurements with measurements derived from spectral images using ImageJ computer software. Statistical tests of the ground measurement data revealed that patterns of seasonal defoliation had a strong effect on the apparent species richness, evenness, and biodiversity of plants as seen aerially. The presence of Sphagnum mosses excluded the presence of other species, but the presence of other plants only excluded the visibility of Sphagnum since it resides in the understory of the layered community. A regression comparing percent cover of the vascular plant functional group and fractal dimensions from a digital camera was statistically significant, indicating that ground and aerial measurements agree and that spectral imaging can be used to save time in the field in place of ground measurements. Additionally, since ecosystem science is such an interdisciplinary field, it provides the perfect platform around which students can apply their scientific knowledge and understanding. Modifications to this project were suggested so that it can be carried out in a secondary school classroom setting while aligning with the Next Generation Science Standards

    Semantic Network Analysis of Ontologies

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    A key argument for modeling knowledge in ontologies is the easy re-use and re-engineering of the knowledge. However, current ontology engineering tools provide only basic functionalities for analyzing ontologies. Since ontologies can be considered as graphs, graph analysis techniques are a suitable answer for this need. Graph analysis has been performed by sociologists for over 60 years, and resulted in the vivid research area of Social Network Analysis (SNA). While social network structures currently receive high attention in the Semantic Web community, there are only very few SNA applications, and virtually none for analyzing the structure of ontologies. We illustrate the benefits of applying SNA to ontologies and the Semantic Web, and discuss which research topics arise on the edge between the two areas. In particular, we discuss how different notions of centrality describe the core content and structure of an ontology. From the rather simple notion of degree centrality over betweenness centrality to the more complex eigenvector centrality, we illustrate the insights these measures provide on two ontologies, which are different in purpose, scope, and size

    A nanoindentation investigation of local strain rate sensitivity in dual-phase Ti alloys

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    Using nanoindentation we have investigated the local strain rate sensitivity in dual-phase Ti alloys, Ti-6Al-2Sn-4Zr-xMo (x=2 and 6), as strain rate sensitivity could be a potential factor causing cold dwell fatigue. Electron backscatter diffraction (EBSD) was used to select hard and soft grain orientations within each of the alloys. Nanoindentation based tests using the continuous stiffness measurement (CSM) method were performed with variable strain rates, on the order of 10−1 to 10−3s−1. Local strain rate sensitivity is determined using a power law linking equivalent flow stress and equivalent plastic strain rate. Analysis of residual impressions using both a scanning electron microscope (SEM) and a focused ion beam (FIB) reveals local deformation around the indents and shows that nanoindentation tested structures containing both α and β phases within individual colonies. This indicates that the indentation results are derived from averaged α/β properties. The results show that a trend of local rate sensitivity in Ti6242 and Ti6246 is strikingly different; as similar rate sensitivities are found in Ti6246 regardless of grain orientation, whilst a grain orientation dependence is observed in Ti6242. These findings are important for understanding dwell fatigue deformation modes, and the methodology demonstrated can be used for screening new alloy designs and microstructures

    Horizontal accuracy assessment of very high resolution Google Earth images in the city of Rome, Italy

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    Google Earth (GE) has recently become the focus of increasing interest and popularity among available online virtual globes used in scientific research projects, due to the free and easily accessed satellite imagery provided with global coverage. Nevertheless, the uses of this service raises several research questions on the quality and uncertainty of spatial data (e.g. positional accuracy, precision, consistency), with implications for potential uses like data collection and validation. This paper aims to analyze the horizontal accuracy of very high resolution (VHR) GE images in the city of Rome (Italy) for the years 2007, 2011, and 2013. The evaluation was conducted by using both Global Positioning System ground truth data and cadastral photogrammetric vertex as independent check points. The validation process includes the comparison of histograms, graph plots, tests of normality, azimuthal direction errors, and the calculation of standard statistical parameters. The results show that GE VHR imageries of Rome have an overall positional accuracy close to 1 m, sufficient for deriving ground truth samples, measurements, and large-scale planimetric maps

    Stiffening and unfolding of early deposited-fibronectin increase proangiogenic factor secretion by breast cancer-associated stromal cells.

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    Fibronectin (Fn) forms a fibrillar network that controls cell behavior in both physiological and diseased conditions including cancer. Indeed, breast cancer-associated stromal cells not only increase the quantity of deposited Fn but also modify its conformation. However, (i) the interplay between mechanical and conformational properties of early tumor-associated Fn networks and (ii) its effect on tumor vascularization remain unclear. Here, we first used the Surface Forces Apparatus to reveal that 3T3-L1 preadipocytes exposed to tumor-secreted factors generate a stiffer Fn matrix relative to control cells. We then show that this early matrix stiffening correlates with increased molecular unfolding in Fn fibers, as determined by Förster Resonance Energy Transfer. Finally, we assessed the resulting changes in adhesion and proangiogenic factor (VEGF) secretion of newly seeded 3T3-L1s, and we examined altered integrin specificity as a potential mechanism of modified cell-matrix interactions through integrin blockers. Our data indicate that tumor-conditioned Fn decreases adhesion while enhancing VEGF secretion by preadipocytes, and that an integrin switch is responsible for such changes. Collectively, our findings suggest that simultaneous stiffening and unfolding of initially deposited tumor-conditioned Fn alters both adhesion and proangiogenic behavior of surrounding stromal cells, likely promoting vascularization and growth of the breast tumor. This work enhances our knowledge of cell - Fn matrix interactions that may be exploited for other biomaterials-based applications, including advanced tissue engineering approaches

    The two sides of a double-skin facade: built intelligent skin or brand image scam?

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    Double-Skin Facade (DSF) buildings regularly appear in popular architectural journals and claims are made that the buildings are either ‘sustainable’, ‘green’, ‘eco-friendly’ or ‘intelligent’. This results in myths about the performance of buildings that are perpetuated by designers eager to maintain a brand image. A literature review of research on the performance of DSFs reveals that the vast majority of the analysis is carried out by simulation methods and that there is a lack of empirical evidence obtained from monitored buildings. This paper will present some early findings from buildings with DSFs that are currently being monitored in Auckland, New Zealand, to assess the contribution of a DSF to reducing the building’s heating and cooling load. It will also analyse the common simulation models to examine whether the models are a reasonable representation of reality. Initial evidence indicates that DSFs in sub-tropical climates offer less energy savings than predicted and could even contribute to increasing cooling loads. It is the hypothesis of this paper that a DSF has become a way in which an excessively glazed building in a warm climate can maintain its transparent architectural image while still claiming to be ‘green’ but with little evidence of any energy savings
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