706 research outputs found

    Hypoadrenocorticism in an aged cat

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    A 13-year-old, female, neutered, domestic longhair cat was referred to the hospital with a two-month history of fluctuating weakness, lethargy, inappetence and intermittently soft stools. Physical examination noted variable mentation, mild tachycardia with poor pulse quality and a body condition score of 1/9. In-house haematology and biochemistry abnormalities included a mild neutrophilia, hyponatraemia, and decreased Na:K ratio of 24 and isosthenuric urine (1.012). The cat was admitted to the hospital for intravenous fluid therapy and management of its electrolyte abnormalities. A low basal cortisol (36 nmol/l) was found on analysis of a stored serum sample, and further investigations confirmed the diagnosis of hypoadrenocorticism. Treatment was implemented initially with hydrocortisone and dexamethasone and continued long term with desoxycorticosterone pivalate and oral prednisolone. More than one year since diagnosis, the cat is clinically well and stable on treatment

    Electrophysiological evidence for memory schemas in the rat hippocampus

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    According to Piaget and Bartlett, learning involves both assimilation of new memories into networks of preexisting knowledge and alteration of existing networks to accommodate new information into existing schemas. Recent evidence suggests that the hippocampus integrates related memories into schemas that link representations of separately acquired experiences. In this thesis, I first review models for how memories of individual experiences become consolidated into the structure of world knowledge. Disruption of consolidated memories can occur during related learning, which suggests that consolidation of new information is the reconsolidation of related memories. The accepted role of the hippocampus during memory consolidation and reconsolidation suggests that it is also involved in modifying appropriate schemas during learning. To study schema development, I trained rats to retrieve rewards at different loci on a maze while recording hippocampal calls. About a quarter of cells were active at multiple goal sites, though the ensemble as a whole distinguished goal loci from one another. When new goals were introduced, cells that had been active at old goal locations began firing at the new locations. This initial generalization decreased in the days after learning. Learning also caused changes in firing patterns at well-learned goal locations. These results suggest that learning was supported by modification of an active schema of spatially related reward loci. In another experiment, I extended these findings to explore a schema of object and place associations. Ensemble activity was influenced by a hierarchy of task dimensions which included: experimental context, rat's spatial location, the reward potential and the identity of sampled objects. As rats learned about new objects, the cells that had previously fired for particular object-place conjunctions generalized their firing patterns to new conjunctions that similarly predicted reward. In both experiments, I observed highly structured representations for a set of related experiences. This organization of hippocampal activity counters key assumptions in standard models of hippocampal function that predict relative independence between memory traces. Instead, these findings reveal neural mechanisms for how the hippocampus develops a relational organization of memories that could support novel, inferential judgments between indirectly related events

    Mobilizing User-Generated Content For Canada’s Digital Advantage

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    Executive Summary: The goal of the Mobilizing User-Generated Content for Canada’s Digital Content Advantage project is to define User-Generated Content (UGC) in its current state, identify successful models built for UGC, and anticipate barriers and policy infrastructure needed to sustain a model to leverage the further development of UGC to Canada\u27s advantage. At the outset, we divided our research into three domains: creative content, small scale tools and collaborative user-generated content. User-generated creative content is becoming increasingly evident throughout the technological ecology through online platforms and online social networks where individuals develop, create and capture information and choose to distribute content through an online platform in a transformative manner. The Internet offers many tools and resources that simplify the various UGC processes and models. Social networking sites such as Facebook, Twitter, YouTube, Vimeo, Flickr and others provide functionality to upload content directly into the site itself, eliminating the need for formatting and conversion, and allowing almost instantaneous access to the content by the user’s social network. The successful sites have been able to integrate content creation, aggregation, distribution, and consumption into a single tool, further eroding some of the traditional dichotomies between content creators and end-users. Along with these larger scale resources, this study also treats small scale tools, which are tools, modifications, and applications that have been created by a user or group of users. There are three main categories of small scale tools. The first is game modifications, or add-ons, which are created by users/players in order to modify the game or assist in its play. The second is modifications, objects, or tools created for virtual worlds such as Second Life. Third, users create applications and tools for mobile devices, such as the iPhone or the Android system. The third domain considers UGC which is generated collaboratively. This category is comprised of wikis, open source software and creative content authored by a group rather than a sole individual. Several highly successful examples of collaborative UGC include Wikipedia, and open source projects such as the Linux operating system, Mozilla Firefox and the Apache platform. Major barriers to the production, distribution and aggregation of collaborative UGC are unduly restrictive intellectual property rights (including copyrights, licensing requirements and technological protection mechanisms). There are several crucial infrastructure and policies required to facilitate collaborative UGC. For example, in the area of copyright policy, a careful balance is needed to provide appropriate protection while still allowing downstream UGC creation. Other policy considerations include issues pertaining to technological protection mechanisms, privacy rights, consumer protection and competition. In terms of infrastructure, broadband internet access is the primary technological infrastructure required to promote collaborative UGC creation. There has recently been a proliferation of literature pertaining to all three of these domains, which are reviewed. Assessments are made about the most effective models and practices for each domain, as well as the barriers which impede further developments. This initial research is used as a basis for generating some tentative conclusions and recommendations for further research about the policy and technological infrastructures required to best mobilize and leverage user-generated content to create additional value in the digital economy internal and external to Canada. Policy recommendations based on this research focus on two principles: balancing the interest of both content owners and users, and creating an enabling environment in which UGC production, distribution, aggregation, and re-use can flourish

    Mobilizing User-Generated Content for Canada’s Digital Content Advantage

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    The goal of the Mobilizing User-Generated Content for Canada’s Digital Content Advantage project is to define User-Generated Content (UGC) in its current state, identify successful models built for UGC, and anticipate barriers and policy infrastructure needed to sustain a model to leverage the further development of UGC to Canada\u27s advantage.This poster session is based on the report, Mobilizing User-Generated Content For Canada’s Digital Advantage (http://ir.lib.uwo.ca/fimspub/21/) and is related to the Brown Bag presentation also presented on March 23, 2011 (http://ir.lib.uwo.ca/fimspres/11/)

    Hyponatremia in a Cold Weather Ultraendurance Race

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    We assessed the incidence and etiology of hyponatremia in the 100-mile (161 km) Iditasport ultramarathon. Subjects (8 cyclists, 8 runners) were weighed and serum sodium was measured pre- and post-race. Race diets were analyzed to determine fluid and sodium consumption. Subjects were split by post-race serum sodium concentration into hyponatremic and normonatremic groups for statistical analyses. Seven of 16 subjects (44%) were hyponatremic. The hyponatremic group exhibited a significant decrease in serum sodium concentration (137.0 to 132.9 mmol/L, and the normonatremic group experienced a significant decrease in weight (82.1 to 80.2 kg) pre- to post-race. The hypornatremic group drank more friud per hour (0.5 versus 0.4 L/h) and consumed less sodium per hour (235 versus 298 mg/h) compared to the normonatremic group. In conclusion, hyponatremia is common in an ultraendurance race held in the extreme cold, and may be caused by excessive fluid consumption and/or inadequate sodium intake

    The largest deep-ocean silicic volcanic eruption of the past century

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    © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Science Advances 4 (2018): e1701121, doi:10.1126/sciadv.1701121.The 2012 submarine eruption of Havre volcano in the Kermadec arc, New Zealand, is the largest deep-ocean eruption in history and one of very few recorded submarine eruptions involving rhyolite magma. It was recognized from a gigantic 400-km2 pumice raft seen in satellite imagery, but the complexity of this event was concealed beneath the sea surface. Mapping, observations, and sampling by submersibles have provided an exceptionally high fidelity record of the seafloor products, which included lava sourced from 14 vents at water depths of 900 to 1220 m, and fragmental deposits including giant pumice clasts up to 9 m in diameter. Most (>75%) of the total erupted volume was partitioned into the pumice raft and transported far from the volcano. The geological record on submarine volcanic edifices in volcanic arcs does not faithfully archive eruption size or magma production.This research was funded by Australian Research Council Postdoctoral fellowships (DP110102196 and DE150101190 to R. Carey), a short-term postdoctoral fellowship grant from the Japan Society for the Promotion of Science (to R. Carey), National Science Foundation grants (OCE1357443 to B.H., OCE1357216 to S.A.S., and EAR1447559 to J.D.L.W.), and a New Zealand Marsden grant (U001616 to J.D.L.W.). J.D.L.W. and A.M. were supported by a research grant and PhD scholarship from the University of Otago. R.W. was supported by NIWA grant COPR1802. J.D.L.W. and F.C.-T. were supported by GNS Science grants CSA-GHZ and CSA-EEZ. M.J. was supported by the U.S. Department of Defense (DoD) through the National Defense Science and Engineering Graduate Fellowship (NDSEG) Program
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