2,892 research outputs found

    A systematic study of the lizards of the deppei group (Genus Cnemidophorus) in Mexico and Guatemala

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    http://deepblue.lib.umich.edu/bitstream/2027.42/56355/1/MP111.pd

    Science, Policy and Partnerships

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    Successful recovery of the Salish Sea requires collaboration between scientists (both biophysical and social) and policy/decision makers. Without this relationship we find ourselves with scientific research that is not relevant to decision making and decisions made without a strong scientific foundation, and without the support of the science community. While there is a great deal of good scientific work currently available to enhance ecosystem recovery decision-making, many of the questions that decision makers currently face require further investigation to address critical uncertainties, or at minimum, collection of data through environmental monitoring or social surveys to fill important gaps. However, it is critical that science does not impede early ecosystem-scale recovery actions; we do have sufficient knowledge to take action. In this panel session we will discuss the relationships between science and policy communities in ecosystem recovery efforts in the Salish Sea, including the science foundation for early action and the science and policy knowledge gaps for recovery at the scale of the Salish Sea. Panel members will include both US and Canadian professionals involved in the science and policy of ecosystem-based management for the Salish Sea. Panelists will consider and discuss such topics as:• An overview of Salish Sea status and trends and what they are really telling us and how should the status and trends influence policy and science• Examples of successes and challenges in science/policy collaboration. • Social constructs and behaviors needed for successful ecosystem recovery• Identified opportunities, specific approaches, and current challenges for science to more effectively inform policy decision-making. Panelists:Katharine Wellman –Moderator, Vice Chair Puget Sound Partnership Science Panel John Stein, Chair Puget Sound Partnership Science Panel Joel Baker, Puget Sound Institute, University of Washington Angela Bonifaci, US Environmental Protection Agency Tracy Collier, Puget Sound Partnership Thomas Leschine, School of Marine and Environmental Affairs, University of WashingtonIan Perry, Department of Fish and Oceans, Canada Terre Satterfield, University of British Columbi

    Decentralized Supply Chain Formation: A Market Protocol and Competitive Equilibrium Analysis

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    Supply chain formation is the process of determining the structure and terms of exchange relationships to enable a multilevel, multiagent production activity. We present a simple model of supply chains, highlighting two characteristic features: hierarchical subtask decomposition, and resource contention. To decentralize the formation process, we introduce a market price system over the resources produced along the chain. In a competitive equilibrium for this system, agents choose locally optimal allocations with respect to prices, and outcomes are optimal overall. To determine prices, we define a market protocol based on distributed, progressive auctions, and myopic, non-strategic agent bidding policies. In the presence of resource contention, this protocol produces better solutions than the greedy protocols common in the artificial intelligence and multiagent systems literature. The protocol often converges to high-value supply chains, and when competitive equilibria exist, typically to approximate competitive equilibria. However, complementarities in agent production technologies can cause the protocol to wastefully allocate inputs to agents that do not produce their outputs. A subsequent decommitment phase recovers a significant fraction of the lost surplus

    An exploration of concepts of community through a case study of UK university web production

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    The paper explores the inter-relation and differences between the concepts of occupational community, community of practice, online community and social network. It uses as a case study illustration the domain of UK university web site production and specifically a listserv for those involved in it. Different latent occupational communities are explored, and the potential for the listserv to help realize these as an active sense of community is considered. The listserv is not (for most participants) a tight knit community of practice, indeed it fails many criteria for an online community. It is perhaps best conceived as a loose knit network of practice, valued for information, implicit support and for the maintenance of weak ties. Through the analysis the case for using strict definitions of the theoretical concepts is made

    Fragments of the earliest land plants

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    The earliest fossil evidence for land plants comes from microscopic dispersed spores. These microfossils are abundant and widely distributed in sediments, and the earliest generally accepted reports are from rocks of mid-Ordovician age (Llanvirn, 475 million years ago). Although distribution, morphology and ultrastructure of the spores indicate that they are derived from terrestrial plants, possibly early relatives of the bryophytes, this interpretation remains controversial as there is little in the way of direct evidence for the parent plants. An additional complicating factor is that there is a significant hiatus between the appearance of the first dispersed spores and fossils of relatively complete land plants (megafossils): spores predate the earliest megafossils (Late Silurian, 425 million year ago) by some 50 million years. Here we report the description of spore-containing plant fragments from Ordovician rocks of Oman. These fossils provide direct evidence for the nature of the spore-producing plants. They confirm that the earliest spores developed in large numbers within sporangia, providing strong evidence that they are the fossilized remains of bona fide land plants. Furthermore, analysis of spore wall ultrastructure supports liverwort affinities

    Outlaw Community Innovations

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    Recent studies of outlaw communities provide qualitative evidence of their existence and the organisation of the underlying innovation processes. We provide descriptive results from a large scale survey of two online outlaw communities focussing on Microsoft's XBox. In line with previous findings, we identify two types of participants in outlaw communities - user innovators and adopters. Based on 2,256 responses, we find that users modify their XBox mainly to be able to increase the set of available functions of their XBox. Users are also motivated to modify their XBox for the sake of having fun and to conduct pirate behaviour. Finally, the results from our survey suggest that user innovators are largely intrinsically motivated by fun and the intellectual stimulation of writing code for homebrew software

    Resistant tissues of modern marchantioid liverworts resemble enigmatic Early Paleozoic microfossils

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    Absence of a substantial pretracheophyte fossil record for bryophytes (otherwise predicted by molecular systematics) poses a major problem in our understanding of earliest land-plant structure. In contrast, there exist enigmatic Cambrian–Devonian microfossils (aggregations of tubes or sheets of cells or possibly a combination of both) controversially interpreted as an extinct group of early land plants known as nematophytes. We used an innovative approach to explore these issues: comparison of tube and cell-sheet microfossils with experimentally degraded modern liverworts as analogues of ancient early land plants. Lower epidermal surface tissues, including rhizoids, of Marchantia polymorpha and Conocephalum conicum were resistant to breakdown after rotting for extended periods or high-temperature acid treatment (acetolysis), suggesting fossilization potential. Cell-sheet and rhizoid remains occurred separately or together depending on the degree of body degradation. Rhizoid break-off at the lower epidermal surface left rimmed pores at the centers of cell rosettes; these were similar in structure, diameter, and distribution to pores characterizing nematophyte cell-sheet microfossils known as Cosmochlaina. The range of Marchantia rhizoid diameters overlapped that of Cosmochlaina pores. Approximately 14% of dry biomass of Marchantia vegetative thalli and 40% of gametangiophores was resistant to acetolysis. Pre- and posttreatment cell-wall autofluorescence suggested the presence of phenolic compounds that likely protect lower epidermal tissues from soil microbe attack and provide dimensional stability to gametangiophores. Our results suggest that at least some microfossils identified as nematophytes may be the remains of early marchantioid liverworts similar in some ways to modern Marchantia and Conocephalum

    Effect of eicosapentaenoic and docosahexaenoic acid on resting and exercise-induced inflammatory and oxidative stress biomarkers: a randomized, placebo controlled, cross-over study

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    <p>Abstract</p> <p>Background</p> <p>The purpose of the present investigation was to determine the effects of EPA/DHA supplementation on resting and exercise-induced inflammation and oxidative stress in exercise-trained men. Fourteen men supplemented with 2224 mg EPA+2208 mg DHA and a placebo for 6 weeks in a random order, double blind cross-over design (with an 8 week washout) prior to performing a 60 minute treadmill climb using a weighted pack. Blood was collected pre and post exercise and analyzed for a variety of oxidative stress and inflammatory biomarkers. Blood lactate, muscle soreness, and creatine kinase activity were also measured.</p> <p>Results</p> <p>Treatment with EPA/DHA resulted in a significant increase in blood levels of both EPA (18 ± 2 μmol·L<sup>-1 </sup>vs. 143 ± 23 μmol·L<sup>-1</sup>; p < 0.0001) and DHA (67 ± 4 μmol·L<sup>-1 </sup>vs. 157 ± 13 μmol·L<sup>-1</sup>; p < 0.0001), while no differences were noted for placebo. Resting levels of CRP and TNF-α were lower with EPA/DHA compared to placebo (p < 0.05). Resting oxidative stress markers were not different (p > 0.05). There was a mild increase in oxidative stress in response to exercise (XO and H<sub>2</sub>O<sub>2</sub>) (p < 0.05). No interaction effects were noted. However, a condition effect was noted for CRP and TNF-α, with lower values with the EPA/DHA condition.</p> <p>Conclusion</p> <p>EPA/DHA supplementation increases blood levels of these fatty acids and results in decreased resting levels of inflammatory biomarkers in exercise-trained men, but does not appear necessary for exercise-induced attenuation in either inflammation or oxidative stress. This may be due to the finding that trained men exhibit a minimal increase in both inflammation and oxidative stress in response to moderate duration (60 minute) aerobic exercise.</p
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