6,751 research outputs found

    Student Demand for Streaming Lecture Video: Emprical Evidence from Undergraduate Economics Classes

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    Real-time lectures recorded on video and streamed over the Internet are a useful supplement to non-classroom learning. However, because recording confines the instructor to the podium, the classroom experience is diminished when there is less social interaction. This study uses choice experiment data to estimate economics students' willingness to pay for streaming lecture video and instructor movement away from the podium. Results show a divide between students who like the flexibility of catching up on missed classes with video and students who do not. For this former group, video enhances the learning experience and students are willing to pay an additional $90 per course for video. An important source of streaming lecture video's value to students is its impact on performance. Knowledge equation estimates show a positive correlation between students' use of video and their cumulative final grade.

    Ecological risks of novel environmental crop technologies using phytoremediation as an example:

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    "Phytoremediation is the use of living plants, known as hyperaccumulators which absorb unusually large amounts of metals in comparison to other plants. The use of classical plant breeding and new molecular techniques offers great potential to develop crops with the ability to clean up polluted sites. While these technologies have gained widespread attention, prior to commercial development, there are risks that must be considered – only a few of which have received even modest examination. Therefore, the focus of this working paper is to explore specific risks associated with phytoremediation and suggest ways in which these risks can be managed so that new, novel, and innovative plant technologies may be applied to provide low cost and efficient environmental solutions. " Authors' AbstractPhytoextraction, Phytomining,

    Policy uncertainty: a new indicator

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    The damaging impact of economic uncertainty on growth has been reasonably well studied - but what happens when there is uncertainty about economic policy-making? Nicholas Bloom and colleagues have developed a measure of this distinct kind of uncertainty, one that shows the value of restoring stability to current policy actions.US economic policy, global financial markets,

    Incorporating project uncertainty in novel environmental biotechnologies: illustrated using phytoremediation

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    "Pollution of the environment by metals and organic contaminants is an intractable global problem, with cleanup costs running into billions of dollars using current engineering technologies. The availability of alternative, cheap and effective technologies would significantly improve the prospects of cleaning-up metal contaminated sites. Phytoremediation has been proposed as an economical and ‘green' method of exploiting plants to extract or degrade the contaminants in the soil. To date, the majority of phytoremediation efforts have been directed at leaping the biological, biochemical and agronomic hurdles to deliver a working technology, with scant attention to the economic outlook other than simple estimates of the cost advantages of phytoremediation over other techniques. In this paper we use a deterministic actuarial model to show that uncertainty in project success (the possibility that full clean up may not be realized) may significantly increase the perceived costs of remediation works for decision-makers." Authors' Abstractbiotechnology, Soil contaminants, Environmental remediation Economic aspects, Industrial crop technologies,

    Physicochemical properties of concentrated Martian surface waters

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    Understanding the processes controlling chemical sedimentation is an important step in deciphering paleoclimatic conditions from the rock records preserved on both Earth and Mars. Clear evidence for subaqueous sedimentation at Meridiani Planum, widespread saline mineral deposits in the Valles Marineris region, and the possible role of saline waters in forming recent geomorphologic features all underscore the need to understand the physical properties of highly concentrated solutions on Mars in addition to, and as a function of, their distinct chemistry. Using thermodynamic models predicting saline mineral solubility, we generate likely brine compositions ranging from bicarbonate-dominated to sulfate-dominated and predict their saline mineralogy. For each brine composition, we then estimate a number of thermal, transport, and colligative properties using established models that have been developed for highly concentrated multicomponent electrolyte solutions. The available experimental data and theoretical models that allow estimation of these physicochemical properties encompass, for the most part, much of the anticipated variation in chemistry for likely Martian brines. These estimates allow significant progress in building a detailed analysis of physical sedimentation at the ancient Martian surface and allow more accurate predictions of thermal behavior and the diffusive transport of matter through chemically distinct solutions under comparatively nonstandard conditions

    Importance of site of infection and antibiotic selection in the treatment of carbapenem-resistant Pseudomonas aeruginosa sepsis

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    ABSTRACT In a retrospective analysis of 215 patients with carbapenem-resistant Pseudomonas aeruginosa sepsis, we observed a significantly higher risk of mortality associated with respiratory tract infection (risk ratio [RR], 1.20; 95% confidence interval [CI], 1.04 to 1.39; P = 0.010) and lower risk with urinary tract infection (RR, 0.80; 95% CI, 0.71 to 0.90; P = 0.004). Aminoglycoside monotherapy was associated with increased mortality, even after adjusting for confounders (adjusted RR, 1.72; 95% CI, 1.03 to 2.85; P = 0.037), consistent across multiple sites of infection. </jats:p

    Applying the Brakes: When to Stop Eating

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    The nucleus accumbens regulates consummatory behaviors, such as eating. In this issue of Neuron, O'Connor et al. (2015) identify dopamine receptor 1-expressing neurons that project to the lateral hypothalamus as mediating rapid control over feeding behavior

    The crustal dynamics intelligent user interface anthology

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    The National Space Science Data Center (NSSDC) has initiated an Intelligent Data Management (IDM) research effort which has, as one of its components, the development of an Intelligent User Interface (IUI). The intent of the IUI is to develop a friendly and intelligent user interface service based on expert systems and natural language processing technologies. The purpose of such a service is to support the large number of potential scientific and engineering users that have need of space and land-related research and technical data, but have little or no experience in query languages or understanding of the information content or architecture of the databases of interest. This document presents the design concepts, development approach and evaluation of the performance of a prototype IUI system for the Crustal Dynamics Project Database, which was developed using a microcomputer-based expert system tool (M. 1), the natural language query processor THEMIS, and the graphics software system GSS. The IUI design is based on a multiple view representation of a database from both the user and database perspective, with intelligent processes to translate between the views
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