7,248 research outputs found

    Using Linked Household-level Datasets to Explain Consumer Response to BSE in Canada

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    Household-level Canadian meat purchases from 2002-2008, household-level egg purchases from 2002-2005 and Food Opinion Survey in 2008 were used to understand how consumers who have different concerns about nutrition react to BSE events and how beef consumption after BSE discoveries were shaped by consumers concerns of food safety and their trust of government and the industry decision makers. Three measures of beef purchased were used to explore consumers’ reaction. A random effects logit model was applied to test whether any beef purchased during a given month. Consumption in terms of unit purchases was measured with a random effects Negative Binomial model and consumption in terms of beef expenditure was measured with a standard random effects model. Consumer behaviors in Alberta differed from Ontario. Consumer reactions to BSE in Alberta were stronger than Ontario. Overall, the more risk consumers attached to BSE, the less beef they purchased in both provinces. Random effects in the three models controlled for unobserved but persistent aspects of households and changed the sign of estimated effects of demographic variables.BSE, mad cow disease, food safety, consumer behavior, Canada, Agribusiness, Agricultural and Food Policy, Consumer/Household Economics, Food Consumption/Nutrition/Food Safety, Marketing,

    A Theorem on Homeomorphic Convergence and Some Applications

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    Borsuk [ 3 ] has given interesting conditions under which a certain function space is separable (see Theorem 3. 1 ). We give a proof for Borsuk\u27s Theorem here and we show how it can be used to establish a useful theorem on homeomorphic convergence. We illustrate the utility of the theorem on homeomorphic convergence by stating and proving several of its consequences. For example we show that the plane (E2) does not contain uncount­ably many pairwise disjoint contina each of which contains a simple triod (Corollary 4. 1 ). We prove that in an uncountable collection G of pairwise disjoint simple closed curves in E2 almost all elements of G must be converged to homeomorphically from both sides by sequences of elements of G (see Theorem 4. 3 ). The same technique allows us to prove the nonexistence of uncountably many pairwise dis -joint wild 2 -spheres in E3. Another interesting consequence of Borsuk\u27s Theorem is Theorem 3. 4 which shows that in each set G consisting of uncountably many com­pact subsets of a metric space, some element of G is an element of convergence. Proofs for this theorem do not often appear in the literature, and, as far as the author knows, the proof given here does not appear in the literature. We wish to emphasize that all the proofs given in this report were constructed by the author without reference to the literature, in fact the author was unaware of the references until after the proofs were given. We given reference at the end of the paper where proofs in the literature can be compared with the proofs given here. We wish to emphasize that all the proofs given in this report were constructed by the author without reference to the literature, in fact the author was unaware of the references until after the proofs were given. We given reference at the end of the paper where proofs in the literature can be compared with the proofs given here

    Linking Mid-century Concentration Targets to Long-Term Climate Change Outcomes

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    We present a framework that could inform the choice of an interim (mid-21st century) target in the making of climate mitigation policy. The idea of interim targets for greenhouse gas concentration has been proposed previously as a way to bridge short- and long-term climate targets, address concerns about the rate of temperature change, and provide guidance in planning for energy infrastructure while scientific understanding improves and long-term climate goals are negotiated. Our analysis relates a wide range of mid-century equivalent CO2 (eCO2) concentrations to rates of temperature increase as well as total long-term temperature increases, accounts for uncertainties in the carbon cycle and the climate response (including climate sensitivity, ocean diffusivity, and aerosol forcing), and provides a rough measure of the economic feasibility of different emissions pathways. Our results show, for example, that for a roughly 50% likelihood of limiting long-term warming to 20C above the pre-industrial level, and with the constraint that global emissions should not have to be reduced by more than 2.5%/year, the mid-century concentration needs to remain below about 470 ppm eCO2 (including only the Kyoto gases and defined relative to a year 2000 baseline). For a roughly 83% likelihood of achieving the same temperature goal, the mid-century target needs to be about 440 ppm. These targets require that emissions between 2010 and 2050 average to approximately the current level and the 1990 level, respectively. Our framework illustrates how delay in emissions reductions in the near term forecloses options in the long term. Finally, we demonstrate how near-term reductions of CO2 from a particular source, deforestation, can significantly facilitate the achievement of long-term temperature goals

    Chalcogenide microsphere fabricated from fibre taper-drawn using resistive heating

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    Over the last decade extreme interest for microsphere resonators has increased rapidly due to their very high quality Q factors, the ease with which they can be manufactured and their versatility in terms of materials and dopants for plenty of passive and active devices. Furthermore, microsphere resonators have the potential to add significant functionality to planar lightwave circuits when coupled to waveguides where they can provide wavelength filtering, delay and low-power switching, and laser functions [1].Recently, chalcogenides are rapidly establishing themselves technologically superior materials for emerging application in non-volatile memory and high speed switching [2] and have been considered for a range of other optoelectronic technologies. Chalcogenide glasses offer a wide wealth of active properties, an exceptionally high nonlinearity, photosensitivity, the ability to be doped with active elements including lanthanides and transitional metals and are able to form detectors, lasers and amplifiers and offer semiconductor, optical, acousto-optic, superconducting and opto-mechanical properties. Unlike any other optical material, they have been formed in to a multitude of form: such as optical fibres, thin films, bulk optical components, microsphere resonators, metamaterials and nanoparticles, patterned by CMOS compatible processing at the sub micron scale. To date, most studies on microsphere resonators have utilized silica microspheres fabricated by melting the tip of an optical fibre with the resulting stem attached to the microsphere used as a tool to place the sphere in the required location while characterizing the microsphere. In this paper high quality chalcogenide (As2S3) microspheres with diameters down to 74 µm are directly fabricated from the taper-drawn using a resistive heating process. A reasonable high quality factor greater than 105 near the wavelength of 1550 nm is demonstrated with an efficient coupling using a fibre taper with a diameter of 2 µm

    Virtual reality-based cloud BIM platform for integrated AEC projects

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    Building Information Modelling (BIM) has demonstrated the need for integrating collaborative design teams’ “project data”, to not only help coordinate the design, engineering, fabrication, construction, and maintenance of various trades, but also facilitate project integration and interchange. Numerous potential benefits have inspired several countries to consider the implications of implementing BIM Level 3 (Cloud) as an innovative way of further enhancing the design, management and delivery process, ergo - a paradigm shift towards Integrated Project Delivery (IPD). Amongst the myriad of the available innovative approaches, web-based platforms are particularly beneficial for integrating visualisation components to give continuous sharing of relevant information for geographically dispersed end users. This study presents a game environment supported by a web-based Virtual Reality cloud platform for integrated AEC projects. This paper further explains the adapted Unified-Software-Development-Process of specifying this cloud computing platform, which employed iterative phases of Elaboration, Construction and Transition. This study presents new understanding and insight into the causal drivers and influences associated with successful decision-making design in non-collocated design teams. Research findings form a stepping-stone for developing new relationship models in collaborative environments, particularly gaming interfaces

    Evaluating the Usability of Automatically Generated Captions for People who are Deaf or Hard of Hearing

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    The accuracy of Automated Speech Recognition (ASR) technology has improved, but it is still imperfect in many settings. Researchers who evaluate ASR performance often focus on improving the Word Error Rate (WER) metric, but WER has been found to have little correlation with human-subject performance on many applications. We propose a new captioning-focused evaluation metric that better predicts the impact of ASR recognition errors on the usability of automatically generated captions for people who are Deaf or Hard of Hearing (DHH). Through a user study with 30 DHH users, we compared our new metric with the traditional WER metric on a caption usability evaluation task. In a side-by-side comparison of pairs of ASR text output (with identical WER), the texts preferred by our new metric were preferred by DHH participants. Further, our metric had significantly higher correlation with DHH participants' subjective scores on the usability of a caption, as compared to the correlation between WER metric and participant subjective scores. This new metric could be used to select ASR systems for captioning applications, and it may be a better metric for ASR researchers to consider when optimizing ASR systems.Comment: 10 pages, 8 figures, published in ACM SIGACCESS Conference on Computers and Accessibility (ASSETS '17

    Single image example-based super-resolution using cross-scale patch matching and Markov random field modelling

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    Example-based super-resolution has become increasingly popular over the last few years for its ability to overcome the limitations of classical multi-frame approach. In this paper we present a new example-based method that uses the input low-resolution image itself as a search space for high-resolution patches by exploiting self-similarity across different resolution scales. Found examples are combined in a high-resolution image by the means of Markov Random Field modelling that forces their global agreement. Additionally, we apply back-projection and steering kernel regression as post-processing techniques. In this way, we are able to produce sharp and artefact-free results that are comparable or better than standard interpolation and state-of-the-art super-resolution techniques

    Local Charge Excesses in Metallic Alloys: a Local Field Coherent Potential Approximation Theory

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    Electronic structure calculations performed on very large supercells have shown that the local charge excesses in metallic alloys are related through simple linear relations to the local electrostatic field resulting from distribution of charges in the whole crystal. By including local external fields in the single site Coherent Potential Approximation theory, we develop a novel theoretical scheme in which the local charge excesses for random alloys can be obtained as the responses to local external fields. Our model maintains all the computational advantages of a single site theory but allows for full charge relaxation at the impurity sites. Through applications to CuPd and CuZn alloys, we find that, as a general rule, non linear charge rearrangements occur at the impurity site as a consequence of the complex phenomena related with the electronic screening of the external potential. This nothwithstanding, we observe that linear relations hold between charge excesses and external potentials, in quantitative agreement with the mentioned supercell calculations, and well beyond the limits of linearity for any other site property.Comment: 11 pages, 1 table, 7 figure

    Presacral Teratocarcinoma Presenting as Anal Fistula and Rectal Adenocarcinoma: A Unique Case Presentation and Literature Review

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    Somatic malignancy arising from presacral or retroperitoneal primary teratoma is extremely rare. We report the case of a 37-year-old male patient with adenocarcinoma of respiratory type arising from primary presacral teratoma, but which first presented as anal fistula and rectal adenocarcinoma. The two tumors show the same morphology and immunophenotype (CK7–CK20+CDx2+). Malignant adenocarcinoma transformations from the normal respiratory epithelium are also found. To the best of our knowledge, this is the second case of respiratory type adenocarcinoma arising from primary presacral mature cystic teratoma

    Optical properties of pyrochlore oxide Pb2Ru2O7δPb_{2}Ru_{2}O_{7-{\delta}}

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    We present optical conductivity spectra for Pb2Ru2O7δPb_{2}Ru_{2}O_{7-{\delta}} single crystal at different temperatures. Among reported pyrochlore ruthenates, this compound exhibits metallic behavior in a wide temperature range and has the least resistivity. At low frequencies, the optical spectra show typical Drude responses, but with a knee feature around 1000 \cm. Above 20000 \cm, a broad absorption feature is observed. Our analysis suggests that the low frequency responses can be understood from two Drude components arising from the partially filled Ru t2gt_{2g} bands with different plasma frequencies and scattering rates. The high frequency broad absorption may be contributed by two interband transitions: from occupied Ru t2gt_{2g} states to empty ege_{g} bands and from the fully filled O 2p bands to unoccupied Ru t2gt_{2g} states.Comment: 4 pages, 6 figure
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