472 research outputs found

    Incorporating sustainable forestry into standards for professional forestry education

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    In 1991, the National Association of Professional Forestry Schools and Colleges (NAPFSC) and the Society of American Foresters (SAF) co-hosted a three-day Forest Resources Education Symposium, entitled Forest Resources Management in the 21st Century: Will Forestry Education Meet the Challenge? The objectives of the national symposium were to present major forces shaping the country\u27s management of forest resources, and then to discuss the adequacy of educational criteria in preparing tomorrow\u27s resource managers to excel under an expanding array of consumer and employer demands. As an outcome, the discussants developed a summary of specific challenges and solutions within five issue areas: The Future of Forestry, Future Educational Needs, Defining Appropriate Curricula, Student Characteristics, and Faculty Characteristics. Many existing problems were identified as a result of that process, as well as potentially useful strategies for corrective action

    Proceedings of the 1987 Airlie House Conference on the Resources Planning Act

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    Isospin breaking in the vector current of the nucleon

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    Extraction of the nucleon's strange form factors from experimental data requires a quantitative understanding of the unavoidable contamination from isospin violation. A number of authors have addressed this issue during the past decade, and their work is reviewed here. The predictions from early models are largely consistent with recent results that rely as much as possible on input from QCD symmetries and related experimental data. The resulting bounds on isospin violation are sufficiently precise to be of value to on-going experimental and theoretical studies of the nucleon's strange form factors.Comment: 5 pages, 3 figures. Presented at the International Workshop "From Parity Violation to Hadronic Structure and more...", Milos, Greece, 16-20 May 2006. Version 2 is only to update Refs. [21] and [25

    VerdictDB: Universalizing Approximate Query Processing

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    Despite 25 years of research in academia, approximate query processing (AQP) has had little industrial adoption. One of the major causes of this slow adoption is the reluctance of traditional vendors to make radical changes to their legacy codebases, and the preoccupation of newer vendors (e.g., SQL-on-Hadoop products) with implementing standard features. Additionally, the few AQP engines that are available are each tied to a specific platform and require users to completely abandon their existing databases---an unrealistic expectation given the infancy of the AQP technology. Therefore, we argue that a universal solution is needed: a database-agnostic approximation engine that will widen the reach of this emerging technology across various platforms. Our proposal, called VerdictDB, uses a middleware architecture that requires no changes to the backend database, and thus, can work with all off-the-shelf engines. Operating at the driver-level, VerdictDB intercepts analytical queries issued to the database and rewrites them into another query that, if executed by any standard relational engine, will yield sufficient information for computing an approximate answer. VerdictDB uses the returned result set to compute an approximate answer and error estimates, which are then passed on to the user or application. However, lack of access to the query execution layer introduces significant challenges in terms of generality, correctness, and efficiency. This paper shows how VerdictDB overcomes these challenges and delivers up to 171×\times speedup (18.45×\times on average) for a variety of existing engines, such as Impala, Spark SQL, and Amazon Redshift, while incurring less than 2.6% relative error. VerdictDB is open-sourced under Apache License.Comment: Extended technical report of the paper that appeared in Proceedings of the 2018 International Conference on Management of Data, pp. 1461-1476. ACM, 201

    Parity Violation in Elastic Electron-Proton Scattering and the Proton's Strange Magnetic Form Factor

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    We report a new measurement of the parity-violating asymmetry in elastic electron scattering from the proton at backward scattering angles. This asymmetry is sensitive to the strange magnetic form factor of the proton as well as electroweak axial radiative corrections. The new measurement of A = -4.92±0.61±0.73 ppm provides a significant constraint on these quantities. The implications for the strange magnetic form factor are discussed in the context of theoretical estimates for the axial corrections

    Jamming and Fluctuations in Granular Drag

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    We investigate the dynamic evolution of jamming in granular media through fluctuations in the granular drag force. The successive collapse and formation of jammed states give a stick-slip nature to the fluctuations which is independent of the contact surface between the grains and the dragged object -- thus implying that the stress-induced collapse is nucleated in the bulk of the granular sample. We also find that while the fluctuations are periodic at small depths, they become "stepped" at large depths, a transition which we interpret as a consequence of the long-range nature of the force chains.Comment: 7 pages, 4 figures, RevTe

    Single-cell deconvolution of head and neck squamous cell carcinoma

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    Complexities in cell-type composition have rightfully led to skepticism and caution in the interpretation of bulk transcriptomic analyses. Recent studies have shown that deconvolution algorithms can be utilized to computationally estimate cell-type proportions from the gene expression data of bulk blood samples, but their performance when applied to tumor tissues, including those from head and neck, remains poorly characterized. Here, we use single-cell data (~6000 single cells) collected from 21 head and neck squamous cell carcinoma (HNSCC) samples to generate cell-type-specific gene expression signatures. We leverage bulk RNA-seq data from \u3e500 HNSCC samples profiled by The Cancer Genome Atlas (TCGA), and using single-cell data as a reference, apply two newly developed deconvolution algorithms (CIBERSORTx and MuSiC) to the bulk transcriptome data to quantitatively estimate cell-type proportions for each tumor in TCGA. We show that these two algorithms produce similar estimates of constituent/major cell-type proportions and that a high T-cell fraction correlates with improved survival. By further characterizing T-cell subpopulations, we identify that regulatory T-cells (

    Radiative Muon Capture on Hydrogen and the Induced Pseudoscalar Coupling

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    The first measurement of the elementary process μpνμnγ\mu^- p \rightarrow \nu_{\mu} n \gamma is reported. A photon pair spectrometer was used to measure the partial branching ratio (2.10±0.22)×1082.10 \pm 0.22) \times 10^{-8} for photons of k > 60 MeV. The value of the weak pseudoscalar coupling constant determined from the partial branching ratio is gp(q2=0.88mμ2)=(9.8±0.7±0.3)ga(0)g_p(q^{2}=-0.88m_{\mu}^2) = (9.8 \pm 0.7 \pm 0.3) \cdot g_a(0), where the first error is the quadrature sum of statistical and systematic uncertainties and the second error is due to the uncertainty in λop\lambda_{op}, the decay rate of the ortho to para pμpp \mu p molecule. This value of g_p is \sim1.5 times the prediction of PCAC and pion-pole dominance.Comment: 13 pages, RevTeX type, 3 figures (encapsulated postscript), submitted to Phys. Rev. Let

    Parity-violating Electron Deuteron Scattering and the Proton's Neutral Weak Axial Vector Form Factor

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    We report on a new measurement of the parity-violating asymmetry in quasielastic electron scattering from the deuteron at backward angles at Q2= 0.038 (GeV/c)2. This quantity provides a determination of the neutral weak axial vector form factor of the nucleon, which can potentially receive large electroweak corrections. The measured asymmetry A=-3.51 +/- 0.57(stat) +/- 0.58(sys)ppm is consistent with theoretical predictions. We also report on updated results of the previous experiment at Q2=0.091 (GeV/c)2, which are also consistent with theoretical predictions.Comment: 4 pages, 2 figures, submitted to Phys. Rev. Let
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