1,347 research outputs found

    Montana Forestry Notes, June 1964

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    This is issue 1: Soil Temperatures in the Lubrecht Experimental Foresthttps://scholarworks.umt.edu/montana_forestry_notes/1000/thumbnail.jp

    Modeling spatiotemporal abundance of mobile wildlife in highly variable environments using boosted GAMLSS hurdle models

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    Modeling organism distributions from survey data involves numerous statistical challenges, including accounting for zero‐inflation, overdispersion, and selection and incorporation of environmental covariates. In environments with high spatial and temporal variability, addressing these challenges often requires numerous assumptions regarding organism distributions and their relationships to biophysical features. These assumptions may limit the resolution or accuracy of predictions resulting from survey‐based distribution models. We propose an iterative modeling approach that incorporates a negative binomial hurdle, followed by modeling of the relationship of organism distribution and abundance to environmental covariates using generalized additive models (GAM) and generalized additive models for location, scale, and shape (GAMLSS). Our approach accounts for key features of survey data by separating binary (presence‐absence) from count (abundance) data, separately modeling the mean and dispersion of count data, and incorporating selection of appropriate covariates and response functions from a suite of potential covariates while avoiding overfitting. We apply our modeling approach to surveys of sea duck abundance and distribution in Nantucket Sound (Massachusetts, USA), which has been proposed as a location for offshore wind energy development. Our model results highlight the importance of spatiotemporal variation in this system, as well as identifying key habitat features including distance to shore, sediment grain size, and seafloor topographic variation. Our work provides a powerful, flexible, and highly repeatable modeling framework with minimal assumptions that can be broadly applied to the modeling of survey data with high spatiotemporal variability. Applying GAMLSS models to the count portion of survey data allows us to incorporate potential overdispersion, which can dramatically affect model results in highly dynamic systems. Our approach is particularly relevant to systems in which little a priori knowledge is available regarding relationships between organism distributions and biophysical features, since it incorporates simultaneous selection of covariates and their functional relationships with organism responses

    Rationale for a Permanent Seismic Network in the U.S. Central Plains Utilizing USArray

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    The eastern two thirds of the coterminous United States (from the Rocky Mountain Front to the east coast) are sparsely equipped with seismic monitoring instruments, with the number of permanent broadband seismic stations per unit area of the order of 5–10% of that in the western U.S. orogenic zone. In this Forum, we use the Central Plains area (CP)—defined here as the fourstate area including Nebraska, Kansas, Iowa, and Missouri—as an example to argue that a greatly densified permanent seismic network in the stable part of the United States could significantly improve our understanding of the processes that led to the formation and four-dimensional structure of the continental lithosphere. The network would also serve as an excellent facility for longterm earthquake monitoring and for public education and outreach. This issue is timely because a state-of-the-art, uniform network could be established by simply converting a small portion of the portable stations in the ongoing USArray project into permanent ones without affecting the overall progress of the USArray

    Hypercomplex quantum mechanics

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    The fundamental axioms of the quantum theory do not explicitly identify the algebraic structure of the linear space for which orthogonal subspaces correspond to the propositions (equivalence classes of physical questions). The projective geometry of the weakly modular orthocomplemented lattice of propositions may be imbedded in a complex Hilbert space; this is the structure which has traditionally been used. This paper reviews some work which has been devoted to generalizing the target space of this imbedding to Hilbert modules of a more general type. In particular, detailed discussion is given of the simplest generalization of the complex Hilbert space, that of the quaternion Hilbert module.Comment: Plain Tex, 11 page

    A Cognitive Model of an Epistemic Community: Mapping the Dynamics of Shallow Lake Ecosystems

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    We used fuzzy cognitive mapping (FCM) to develop a generic shallow lake ecosystem model by augmenting the individual cognitive maps drawn by 8 scientists working in the area of shallow lake ecology. We calculated graph theoretical indices of the individual cognitive maps and the collective cognitive map produced by augmentation. The graph theoretical indices revealed internal cycles showing non-linear dynamics in the shallow lake ecosystem. The ecological processes were organized democratically without a top-down hierarchical structure. The steady state condition of the generic model was a characteristic turbid shallow lake ecosystem since there were no dynamic environmental changes that could cause shifts between a turbid and a clearwater state, and the generic model indicated that only a dynamic disturbance regime could maintain the clearwater state. The model developed herein captured the empirical behavior of shallow lakes, and contained the basic model of the Alternative Stable States Theory. In addition, our model expanded the basic model by quantifying the relative effects of connections and by extending it. In our expanded model we ran 4 simulations: harvesting submerged plants, nutrient reduction, fish removal without nutrient reduction, and biomanipulation. Only biomanipulation, which included fish removal and nutrient reduction, had the potential to shift the turbid state into clearwater state. The structure and relationships in the generic model as well as the outcomes of the management simulations were supported by actual field studies in shallow lake ecosystems. Thus, fuzzy cognitive mapping methodology enabled us to understand the complex structure of shallow lake ecosystems as a whole and obtain a valid generic model based on tacit knowledge of experts in the field.Comment: 24 pages, 5 Figure

    English secondary students’ thinking about the status of scientific theories: consistent, comprehensive, coherent and extensively evidenced explanations of aspects of the natural world – or just ‘an idea someone has’

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    Teaching about the nature of science (NOS) is seen as a priority for science education in many national contexts. The present paper focuses on one central issue in learning about NOS: understanding the nature and status of scientific theories. A key challenge in teaching about NOS is to persuade students that scientific knowledge is generally robust and reliable, yet also in principle always open to challenge and modification. Theories play a central role, as they are a form of conjectural knowledge that over time may be abandoned, replaced, modified, yet sometimes become well established as current best scientific understanding. The present paper reports on findings from interviews with 13–14 year olds in England where target knowledge presents theories as ‘consistent, comprehensive, coherent and extensively evidenced explanations of aspects of the natural world’. Student thinking reflected a two-tier typology of scientific knowledge in which largely unsupported imaginative ideas (‘theories’) became transformed into fairly definitive knowledge (such as laws) through relatively straightforward testing. These results are considered in relation to research into intellectual development which indicates that effective teaching in this area requires careful scaffolding of student learning, but has potential to contribute to supporting intellectual development across the curriculum.This is the author accepted manuscript. The final version is available from Taylor & Francis via http://dx.doi.org/10.1080/09585176.2015.104392

    Therapeutic DNA vaccine induces broad T cell responses in the gut and sustained protection from viral rebound and AIDS in SIV-infected rhesus macaques.

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    Immunotherapies that induce durable immune control of chronic HIV infection may eliminate the need for life-long dependence on drugs. We investigated a DNA vaccine formulated with a novel genetic adjuvant that stimulates immune responses in the blood and gut for the ability to improve therapy in rhesus macaques chronically infected with SIV. Using the SIV-macaque model for AIDS, we show that epidermal co-delivery of plasmids expressing SIV Gag, RT, Nef and Env, and the mucosal adjuvant, heat-labile E. coli enterotoxin (LT), during antiretroviral therapy (ART) induced a substantial 2-4-log fold reduction in mean virus burden in both the gut and blood when compared to unvaccinated controls and provided durable protection from viral rebound and disease progression after the drug was discontinued. This effect was associated with significant increases in IFN-γ T cell responses in both the blood and gut and SIV-specific CD8+ T cells with dual TNF-α and cytolytic effector functions in the blood. Importantly, a broader specificity in the T cell response seen in the gut, but not the blood, significantly correlated with a reduction in virus production in mucosal tissues and a lower virus burden in plasma. We conclude that immunizing with vaccines that induce immune responses in mucosal gut tissue could reduce residual viral reservoirs during drug therapy and improve long-term treatment of HIV infection in humans
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