2,391 research outputs found

    MP754: A Literature Review of the Effects of Intensive Forestry on Forest Structure and Plant Community Composition at the Stand and Landscape Levels

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    The effects of intensive forest management on forest structure and plant community composition are not well documented, particularly with respect to the forests in the Northeast. This review presents a six-part synthesis of the literature. The first section considers the effects of intensive forestry practices within the context of naturally regenerated stands. The second section reviews the changes associated with the planting of conifers in softwood sites, as well as those previously occupied by hardwood and mixed-wood stands. The third examines the impacts of intensive management specifically on bryophytes and lichens. The fourth section discusses changes in dead organic matter components of the stand and the fifth with the impact on tree pests. The final section views the effects of intensive forestry from the landscape-scale perspective and is followed by summary and conclusions. While this paper provides a summary of scientific information, it does not recommend policy or propose how the forest should be managed.https://digitalcommons.library.umaine.edu/aes_miscpubs/1022/thumbnail.jp

    The “Critical” Elements of Illness Management and Recovery: Comparing Methodological Approaches

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    This study examined three methodological approaches to defining the critical elements of Illness Management and Recovery (IMR), a curriculum-based approach to recovery. Sixty-seven IMR experts rated the criticality of 16 IMR elements on three dimensions: defining, essential, and impactful. Three elements (Recovery Orientation, Goal Setting and Follow-up, and IMR Curriculum) met all criteria for essential and defining and all but the most stringent criteria for impactful. Practitioners should consider competence in these areas as preeminent. The remaining 13 elements met varying criteria for essential and impactful. Findings suggest that criticality is a multifaceted construct, necessitating judgments about model elements across different criticality dimensions

    Alteration of In Vivo Cellulose Ribbon Assembly by Carboxymethylcellulose and Other Cellulose Derivatives

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    In vivo cellulose ribbon assembly by the Gram-negative bacterium Acetobacter xylinum can be altered by incubation in carboxymethylcellulose (CMC), a negatively charged water-soluble cellulose derivative, and also by incubation in a variety of neutral, water-soluble cellulose derivatives. In the presence of all of these substituted celluloses, normal fasciation of microfibril bundles to form the typical twisting ribbon is prevented. Alteration of ribbon assembly is most extensive in the presence of CMC, which often induces synthesis of separate, intertwining bundles of microfibrils. Freeze- etch preparations of the bacterial outer membrane suggest that particles that are thought to be associated with cellulose synthesis or extrusion may be specifically organized to mediate synthesis of microfibril bundles. These data support the previous hypothesis that the cellulose ribbon of A. xylinum is formed by a hierarchical, cell- directed, self-assembly process. The relationship of these results to the regulation of cellulose microfibril size and wall extensibility in plant cell walls is discussed

    Economics of Drip Irrigation for Juice Grape Vineyards in New York State

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    R.B. 99-01Grape growers need investment and cost guidelines for drip irrigation to evaluate the economics of getting vines into production as quickly as possible and to avoid periods of drought during the productive life of the vineyard. The benefits of irrigation may include: better vine survival, earlier fruit production, greater yields, more efficient distribution of nutrients, less plant stress, reduced yield variability and improved fruit quality. Research was undertaken to determine drip irrigation investment and annual costs. This project was designed to assist growers in determining the investment, fixed and variable annual costs and expected returns from drip irrigation. Irrigation suppliers provided typical equipment needs and investment costs for various drip irrigation designs. Economic worksheets are provided to assist growers in estimating fixed and variable costs of drip irrigation. The economics of yield data were applied to replicated multiyear irrigation studies to assist growers in determining yield response from drip irrigation. Net present value (NPV) methodology was used to determine the discounted break-even investment results from published responses to drip irrigation. Growers with typical drip irrigation systems and various water sources can expect investments in drip irrigation of 550to550 to 1,150 per acre with 10 acre blocks of vines. Based upon eight years of data from trials in Fredonia, NY, in the Lake Erie grape belt, average yield increases due to irrigation on establishment and growing of Niagara grapes were 2.8 ton per production year per acre, resulting in a break-even investment of approximately 1,600peracre.ButonestablishedminimalprunedConcordgrapes,sevenyearsofdatashoweda1.1tonincreaseduetoirrigationandabreakeveninvestmentofonly1,600 per acre. But on established minimal pruned Concord grapes, seven years of data showed a 1.1 ton increase due to irrigation and a break-even investment of only 200 per acre which was well below the total cost of a complete microirrigation drip system. On a new planting of Concords, with droughty soils, the analysis may very well show cost effectiveness. Growers who were interviewed were unable to quantify the benefits and costs of drip irrigation but were pleased with their irrigated yields and brix responses from drip irrigation. This analysis has provided the economic rationale for the investment in microirrigation with some varieties and under certain soil types

    Predicting the cosmological constant with the scale-factor cutoff measure

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    It is well known that anthropic selection from a landscape with a flat prior distribution of cosmological constant Lambda gives a reasonable fit to observation. However, a realistic model of the multiverse has a physical volume that diverges with time, and the predicted distribution of Lambda depends on how the spacetime volume is regulated. We study a simple model of the multiverse with probabilities regulated by a scale-factor cutoff, and calculate the resulting distribution, considering both positive and negative values of Lambda. The results are in good agreement with observation. In particular, the scale-factor cutoff strongly suppresses the probability for values of Lambda that are more than about ten times the observed value. We also discuss several qualitative features of the scale-factor cutoff, including aspects of the distributions of the curvature parameter Omega and the primordial density contrast Q.Comment: 16 pages, 6 figures, 2 appendice

    Measuring aortic pulse wave velocity using high-field cardiovascular magnetic resonance: comparison of techniques

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    <p>Abstract</p> <p>Background</p> <p>The assessment of arterial stiffness is increasingly used for evaluating patients with different cardiovascular diseases as the mechanical properties of major arteries are often altered. Aortic stiffness can be noninvasively estimated by measuring pulse wave velocity (PWV). Several methods have been proposed for measuring PWV using velocity-encoded cardiovascular magnetic resonance (CMR), including transit-time (TT), flow-area (QA), and cross-correlation (XC) methods. However, assessment and comparison of these techniques at high field strength has not yet been performed. In this work, the TT, QA, and XC techniques were clinically tested at 3 Tesla and compared to each other.</p> <p>Methods</p> <p>Fifty cardiovascular patients and six volunteers were scanned to acquire the necessary images. The six volunteer scans were performed twice to test inter-scan reproducibility. Patient images were analyzed using the TT, XC, and QA methods to determine PWV. Two observers analyzed the images to determine inter-observer and intra-observer variabilities. The PWV measurements by the three methods were compared to each other to test inter-method variability. To illustrate the importance of PWV using CMR, the degree of aortic stiffness was assessed using PWV and related to LV dysfunction in five patients with diastolic heart failure patients and five matched volunteers.</p> <p>Results</p> <p>The inter-observer and intra-observer variability results showed no bias between the different techniques. The TT and XC results were more reproducible than the QA; the mean (SD) inter-observer/intra-observer PWV differences were -0.12(1.3)/-0.04(0.4) for TT, 0.2(1.3)/0.09(0.9) for XC, and 0.6(1.6)/0.2(1.4) m/s for QA methods, respectively. The correlation coefficients (r) for the inter-observer/intra-observer comparisons were 0.94/0.99, 0.88/0.94, and 0.83/0.92 for the TT, XC, and QA methods, respectively. The inter-scan reproducibility results showed low variability between the repeated scans (mean (SD) PWV difference = -0.02(0.4) m/s and r = 0.96). The inter-method variability results showed strong correlation between the TT and XC measurements, but less correlation with QA: r = 0.95, 0.87, and 0.89, and mean (SD) PWV differences = -0.12(1.0), 0.8(1.7), and 0.65(1.6) m/s for TT-XC, TT-QA, and XC-QA, respectively. Finally, in the group of diastolic heart failure patient, PWV was significantly higher (6.3 ± 1.9 m/s) than in volunteers (3.5 ± 1.4 m/s), and the degree of LV diastolic dysfunction showed good correlation with aortic PWV.</p> <p>Conclusions</p> <p>In conclusion, while each of the studied methods has its own advantages and disadvantages, at high field strength, the TT and XC methods result in closer and more reproducible aortic PWV measurements, and the associated image processing requires less user interaction, than in the QA method. The choice of the analysis technique depends on the vessel segment geometry and available image quality.</p

    A Chandra Observation of Abell 13: Investigating the Origin of the Radio Relic

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    We present results from the Chandra X-ray observation of Abell 13, a galaxy cluster that contains an unusual noncentral radio source, also known as a radio relic. This is the first pointed X-ray observation of Abell 13, providing a more sensitive study of the properties of the X-ray gas. The X-ray emission from Abell 13 is extended to the northwest of the X-ray peak and shows substructure indicative of a recent merger event. The cluster X-ray emission is centered on the bright galaxy H of Slee et al. 2001. We find no evidence for a cooling flow in the cluster. A knot of excess X-ray emission is coincident with the other bright elliptical galaxy F. This knot of emission has properties similar to the enhanced emission associated with the large galaxies in the Coma cluster. With these Chandra data we are able to compare the properties of the hot X-ray gas with those of the radio relic from VLA data, to study the interaction of the X-ray gas with the radio emitting electrons. Our results suggest that the radio relic is associated with cooler gas in the cluster. We suggest two explanations for the coincidence of the cooler gas and radio source. First, the gas may have been uplifted by the radio relic from the cluster core. Alternatively, the relic and cool gas may have been displaced from the central galaxy during the cluster merger event.Comment: 11 pages, 9 figures, Accepted for Publication in the Astrophysical Journal, higher-resolution figures can be found at http://www.astro.virginia.edu/~amj3r/Abell13

    Chirality Violation in QCD Reggeon Interactions

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    The appearance of the triangle graph infra-red axial anomaly in reduced quark loops contributing to QCD triple-regge interactions is studied. In a dispersion relation formalism, the anomaly can only be present in the contributions of unphysical triple discontinuities. In this paper an asymptotic discontinuity analysis is applied to high-order feynman diagrams to show that the anomaly does indeed occur in sufficiently high-order reggeized gluon interactions. The reggeon states involved must contain reggeized gluon combinations with the quantum numbers of the anomaly (winding-number) current. A direct connection with the well-known U(1) problem is thus established. Closely related diagrams that contribute to the pion/pomeron and triple pomeron couplings in color superconducting QCD are also discussed.Comment: 52 pages, 29 PS figures in the tex

    An integrated comparative phosphoproteomic and bioinformatic approach reveals a novel class of MPM-2 motifs upregulated in EGFRvIII-expressing Glioblastoma Cells

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    Glioblastoma (GBM, WHO grade IV) is an aggressively proliferative and invasive brain tumor that carries a poor clinical prognosis with a median survival of 9 to 12 months. In a prior phosphoproteomic study performed in the U87MG glioblastoma cell line, we identified tyrosine phosphorylation events that are regulated as a result of titrating EGFRvIII, a constitutively active mutant of the epidermal growth factor receptor (EGFR) associated with poor prognosis in GBM patients. In the present study, we have used the phosphoserine/phosphothreonine-specific antibody MPM-2 (mitotic protein monoclonal #2) to quantify serine/threonine phosphorylation events in the same cell lines. By employing a bioinformatic tool to identify amino acid sequence motifs regulated in response to increasing oncogene levels, a set of previously undescribed MPM-2 epitope sequence motifs orthogonal to the canonical “pS/pT-P” motif was identified. These motifs contain acidic amino acids in combinations of the −5, −2, +1, +3, and +5 positions relative to the phosphorylated amino acid. Phosphopeptides containing these motifs are upregulated in cells expressing EGFRvIII, raising the possibility of a general role for a previously unrecognized acidophilic kinase (e.g. casein kinase II (CK2)) in cell proliferation downstream of EGFR signaling.National Cancer Institute (U.S.). Integrative Cancer Biology Program (grant U54-CA112967)National Cancer Institute (U.S.). Bioengineering Research Partnership (grant R01-CA96504)National Institutes of Health (U.S.) (grant R01-GM60594
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