1,275 research outputs found

    Consortia in Postsecondary Education

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    This article presents the concept of consortia as formal collaborative arrange- ments between institutions, which are designed to enhance academic programs or other services provided. Forty years of experience in the United States are reviewed through the literature, and a synopsis of consortia in Canada is presented. From this review, some "pros and cons" of consortia are raised. Advantages include: reducing duplication, improving quality, increasing program diversity, increasing accessibility, financial advancement, improving communication and more effective planning and control. Cautions raised include: lack of trust, unequal commitment by members, undue emphasis on reducing costs, lack of clear expectations, mismatching membership and mission and irrelevant structure and theory. The authors conclude that the promise of consortia is such that more detailed study of Canadian consortia is warranted

    Determination of urban traffic movements with electrical analogues

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    Thesis (M.C.P.) Massachusetts Institute of Technology. Dept. of Architecture, 1954.by James M. Small.M.C.P

    The Identification and Estimation of Direct and Indirect Effects in A/B Tests through Causal Mediation Analysis

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    E-commerce companies have a number of online products, such as organic search, sponsored search, and recommendation modules, to fulfill customer needs. Although each of these products provides a unique opportunity for users to interact with a portion of the overall inventory, they are all similar channels for users and compete for limited time and monetary budgets of users. To optimize users' overall experiences on an E-commerce platform, instead of understanding and improving different products separately, it is important to gain insights into the evidence that a change in one product would induce users to change their behaviors in others, which may be due to the fact that these products are functionally similar. In this paper, we introduce causal mediation analysis as a formal statistical tool to reveal the underlying causal mechanisms. Existing literature provides little guidance on cases where multiple unmeasured causally-dependent mediators exist, which are common in A/B tests. We seek a novel approach to identify in those scenarios direct and indirect effects of the treatment. In the end, we demonstrate the effectiveness of the proposed method in data from Etsy's real A/B tests and shed lights on complex relationships between different products.Comment: Accepted by The 25th ACM SIGKDD Conference on Knowledge Discovery and DataMining (KDD '19), August 4-8, 2019, Anchorage, AK, US

    Dialkylenecarbonate-Bridged Polysilsesquioxanes: Hybrid Organic-Inorganic Sol-Gels with a Thermally Labile Bridging Group

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    In this paper, we introduce a new approach for altering the properties of bridged polysilsesquioxane xerogels using post-processing modification of the polymeric network. The bridging organic group contains latent functionalities that can be liberated thermally, photochemically, or by chemical means after the gel has been processed to a xerogel. These modifications can produce changes in density, volubility, porosity, and or chemical properties of the material. Since every monomer possesses two latent functional groups, the technique allows for the introduction of high levels of functionality in hybrid organic-inorganic materials. Dialkylenecarbonate-bridged polysilsesquioxane gels were prepared by the sol-gel polymerization of bis(triethoxysilylpropyl)carbonate (1) and bis(triethoxysilylisobutyl)-carbonate (2). Thermal treatment of the resulting non-porous xerogels and aerogels at 300-350 C resulted in quantitative decarboxylation of the dialkylenecarbonate bridging groups to give new hydroxyalkyl and olefinic substituted polysilsesquioxane monolithic xerogels and aerogels that can not be directly prepared through direct sol-gel polymerization of organotrialkoxysilanes

    Actes du CongrÚs CollÚges célébrations 92

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    Également disponible en version papierTitre de l'Ă©cran-titre (visionnĂ© le 12 aoĂ»t 2009)Bibliogr.: p.

    River export of nutrients and organic matter from the North Slope of Alaska to the Beaufort Sea

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    Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Water Resources Research 50 (2014): 1823–1839, doi:10.1002/2013WR014722.While river-borne materials are recognized as important resources supporting coastal ecosystems around the world, estimates of river export from the North Slope of Alaska have been limited by a scarcity of water chemistry and river discharge data. This paper quantifies water, nutrient, and organic matter export from the three largest rivers (Sagavanirktok, Kuparuk, and Colville) that drain Alaska's North Slope and discusses the potential importance of river inputs for biological production in coastal waters of the Alaskan Beaufort Sea. Together these rivers export ∌297,000 metric tons of organic carbon and ∌18,000 metric tons of organic nitrogen each year. Annual fluxes of nitrate-N, ammonium-N, and soluble reactive phosphorus are approximately 1750, 200, and 140 metric tons per year, respectively. Constituent export from Alaska's North Slope is dominated by the Colville River. This is in part due to its larger size, but also because constituent yields are greater in the Colville watershed. River-supplied nitrogen may be more important to productivity along the Alaskan Beaufort Sea coast than previously thought. However, given the dominance of organic nitrogen export, the potential role of river-supplied nitrogen in support of primary production depends strongly on remineralization mechanisms. Although rivers draining the North Slope of Alaska make only a small contribution to overall river export from the pan-arctic watershed, comparisons with major arctic rivers reveal unique regional characteristics as well as remarkable similarities among different regions and scales. Such information is crucial for development of robust river export models that represent the arctic system as a whole.Funding for this project was provided by a grant from the National Science Foundation Office of Polar Programs (NSF-OPP-0436118) as part of the Arctic System Science (ARCSS) Study of the Northern Alaska Coastal System (SNACS) effort.2014-08-2
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