20,807 research outputs found

    Analysis and Conservation of Native Forests at Kessler Mountain Fayetteville, Arkansas

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    Kessler Mountain in Fayetteville Arkansas has long been recognized for its beauty and natural resources. Parts of Kessler Mountain have been homesteaded and developed in the past, but most of the mountain has remained relatively undisturbed. The planned development of over 4,000 housing units to cover Kessler Mountain stimulated controversy and consideration of other management alternatives. A twist of fate involving an economic recession, a dedicated group of outdoor recreation enthusiasts, and environmental conservationists led to the permanent protection of 384 acres in the Kessler Mountain Regional Park. To help evaluate the natural resources at Kessler Mountain, forest composition, structure, and tree age were measured at two old growth forest parcels on Kessler Mountain. Forest understory and overstory were surveyed and increment cores were collected from select overstory trees. The overstory of the post oak (Quercus stellata) site (Site A) was dominated by post oak and northern red oak (Quercus rubra). The understory was dominated by northern red oak and black locust (Robnia pseudoacacia). The oldest post oak trees at the post oak site were in the 250 to 300-year-old age class based on dendrochronological analysis of core samples. The overstory of the chinkapin oak (Quercus muehlenbergii) site (Site B) was dominated by sugar maple (Acer saccharum var. saccharum) and chinkapin oak. The understory was dominated by eastern red cedar (Juniperous virginiana) and northern red oak. The oldest chinkapin oak trees at Site B were in the 200 to 250-year-old age class. The data suggest that chinkapin oak and post oak are currently not regenerating at rates necessary to maintain long term dominance in the canopy at these particular study sites on Kessler Mountain. As more land is conserved in the region significant planning and funding need to be dedicated to proper management of these lands to maintain biodiversity and healthy forests

    Darkness Within:...

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    A boost for the EW SUSY hunt: monojet-like search for compressed sleptons at LHC14 with 100 fb^-1

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    Current Large Hadron Collider (LHC) analyses are blind to compressed supersymmetry (SUSY) models with sleptons near the lightest super partner (LSP) in mass: ml~mχ~10Δm60m_{\tilde{l}} - m_{\tilde{\chi}_1^0} \equiv \Delta m \lesssim 60 GeV. We present a search sensitive to the very compressed range 3 GeV<Δm<24 GeV3~\text{GeV} < \Delta m < 24~\text{GeV} using the channel ppl~+l~+jetp p \rightarrow \tilde{l}^+ \tilde{l}^- +\rm{jet} \rightarrow l+lχ~10χ~10+jetl^+ l^- \tilde{\chi}_1^0 \tilde{\chi}_1^0 +\rm{jet} with soft same-flavor leptons and one hard jet from initial state radiation (pTj>100p_{\rm T}^j >100 GeV). The sleptons recoil against the jet boosting them and their decay products, making the leptons detectable and providing substantial missing transverse momentum. We use the kinematic variable mT2m_{\rm T 2} along with a different-flavor control region to reduce the large standard model backgrounds and control systematic uncertainty. We find the analysis should allow LHC14 with 100 fb1100~\text{fb}^{-1} to search for degenerate left-handed selectrons and smuons in the compressed region up to ml~L150m_{\tilde{l}_L} \lesssim 150 GeV. In addition, it should be sensitive to ml~L110m_{\tilde{l}_L} \lesssim 110 GeV for the very challenging case of auto-concealed SUSY, in which left-handed sleptons decay to the Kaluza-Klein tower of a modulino LSP which lives in d=6d=6 extra dimensions. In both the compressed spectrum and auto-concealed SUSY scenarios this analysis will need more data to improve on LEP2 limits for right-handed sleptons due to their smaller cross sections.Comment: 15 pages, 3 figures, updated citations in v

    Directors and the missing ‘articles’

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    On Thin Air Reads: Towards an Event Structures Model of Relaxed Memory

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    To model relaxed memory, we propose confusion-free event structures over an alphabet with a justification relation. Executions are modeled by justified configurations, where every read event has a justifying write event. Justification alone is too weak a criterion, since it allows cycles of the kind that result in so-called thin-air reads. Acyclic justification forbids such cycles, but also invalidates event reorderings that result from compiler optimizations and dynamic instruction scheduling. We propose the notion of well-justification, based on a game-like model, which strikes a middle ground. We show that well-justified configurations satisfy the DRF theorem: in any data-race free program, all well-justified configurations are sequentially consistent. We also show that rely-guarantee reasoning is sound for well-justified configurations, but not for justified configurations. For example, well-justified configurations are type-safe. Well-justification allows many, but not all reorderings performed by relaxed memory. In particular, it fails to validate the commutation of independent reads. We discuss variations that may address these shortcomings

    SIGIR: scholar vs. scholars' interpretation

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    Google Scholar allows researchers to search through a free and extensive source of information on scientific publications. In this paper we show that within the limited context of SIGIR proceedings, the rankings created by Google Scholar are both significantly different and very negatively correlated with those of domain experts

    Query independent measures of annotation and annotator impact

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    The modern-day web-user plays a far more active role in the creation of content for the web as a whole. In this paper we present Annoby, a free-text annotation system built to give users a more interactive experience of the events of the Rugby World Cup 2007. Annotations can be used for query-independent ranking of both the annotations and the original recorded video footage (or documents) which has been annotated, based on the social interactions of a community of users. We present two algorithms, AuthorRank and MessageRank, designed to take advantage of these interactions so as to provide a means of ranking documents by their social impact
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