68 research outputs found

    Improving Urban Tree Care in the Great Plains: Impacts of the Nebraska Tree Care Workshops

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    Urban and community forests possess many benefits that enhance our quality of life. The Nebraska Tree Care Workshop is a tree care training program designed to enhance tree management in urban settings. This article describes the impacts that the workshop has had on Nebraska\u27s community tree resources. Data was collected using a survey of past participants. The study found that creating a large cadre of people, well trained in tree selection and care, has had a positive impact on community tree resources across the state

    G02-1466 Determining the Need to Fertilize Landscape Trees and Shrubs (Revised March 2004)

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    Most Nebraska soils are fertile enough to support tree and shrub growth without applying fertilizer. However, when woody plants exhibit poor growth or reduced vigor, yet have had adequate moisture and are not experiencing pest problems or other environmental limitations, the proper applicatin of fertilizer may be necessary. This NebGuide explains how to determine if fertilization of established trees and shrubs is required and how to apply the needed amount

    Big Bang Nucleosynthesis Constraints on the Self-Gravity of Pressure

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    Using big bang nucleosynthesis and present, high-precision measurements of light element abundances, we constrain the self-gravity of radiation pressure in the early universe. The self-gravity of pressure is strictly non-Newtonian, and thus the constraints we set provide a direct test of this prediction of general relativity and of the standard, Robertson-Walker-Friedmann cosmology.Comment: 5 pages, 1 figure. This paper was developed from an earlier version which was posted as arXiv:0707.358

    PERENNIAL CROPS FOR BIO-FUELS AND CONSERVATION

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    Perennial woody crops have the potential to contribute significantly to the production of bio-fuels while simultaneously helping to provide a wide range of conservation benefits. Among these benefits are increased biological diversity in the landscape, conservation of soil and water resources, maintenance of forest ecosystem productivity and health, contribution to the global carbon cycle, and provision of socioeconomic benefits. Short rotation woody crops, like hybrid poplar and willow, grow rapidly and can reach 15-25 feet in height after only three years. Currently, non-irrigated yields can be sustained at about 5 dry tons/acre/year and are increasing as plant breeding, nutrient management, and weed control advances are made. The high hemi-cellulose and cellulose content of woody biomass result in favorable net energy conversion ratios of 1:11 when co-fired with coal and 1:16 when undergoing gasification. Directing this wood fiber into bio-fuels would benefit both the energy sector and forest and farm landowners, while providing an array of conservation benefits and ecological services. The amount of biofuel that can be sustainably produced each year from perennial crops is potentially very large. The next Farm Bill affords an opportunity to insure that this potential can be more fully realized

    PERENNIAL CROPS FOR BIO-FUELS AND CONSERVATION

    Get PDF
    Perennial woody crops have the potential to contribute significantly to the production of bio-fuels while simultaneously helping to provide a wide range of conservation benefits. Among these benefits are increased biological diversity in the landscape, conservation of soil and water resources, maintenance of forest ecosystem productivity and health, contribution to the global carbon cycle, and provision of socioeconomic benefits. Short rotation woody crops, like hybrid poplar and willow, grow rapidly and can reach 15-25 feet in height after only three years. Currently, non-irrigated yields can be sustained at about 5 dry tons/acre/year and are increasing as plant breeding, nutrient management, and weed control advances are made. The high hemi-cellulose and cellulose content of woody biomass result in favorable net energy conversion ratios of 1:11 when co-fired with coal and 1:16 when undergoing gasification. Directing this wood fiber into bio-fuels would benefit both the energy sector and forest and farm landowners, while providing an array of conservation benefits and ecological services. The amount of biofuel that can be sustainably produced each year from perennial crops is potentially very large. The next Farm Bill affords an opportunity to insure that this potential can be more fully realized

    PERENNIAL CROPS FOR BIO-FUELS AND CONSERVATION

    Get PDF
    Perennial woody crops have the potential to contribute significantly to the production of bio-fuels while simultaneously helping to provide a wide range of conservation benefits. Among these benefits are increased biological diversity in the landscape, conservation of soil and water resources, maintenance of forest ecosystem productivity and health, contribution to the global carbon cycle, and provision of socioeconomic benefits. Short rotation woody crops, like hybrid poplar and willow, grow rapidly and can reach 15-25 feet in height after only three years. Currently, non-irrigated yields can be sustained at about 5 dry tons/acre/year and are increasing as plant breeding, nutrient management, and weed control advances are made. The high hemi-cellulose and cellulose content of woody biomass result in favorable net energy conversion ratios of 1:11 when co-fired with coal and 1:16 when undergoing gasification. Directing this wood fiber into bio-fuels would benefit both the energy sector and forest and farm landowners, while providing an array of conservation benefits and ecological services. The amount of biofuel that can be sustainably produced each year from perennial crops is potentially very large. The next Farm Bill affords an opportunity to insure that this potential can be more fully realized

    Adoption of Riparian Forest Buffers on Private Lands in Nebraska, USA

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    Pesticide and nutrient runoff from agricultural fields is a socio-environmental problem in the Midwestern United States. Riparian forest buffers (RFBs) are a proven conservation practice that effectively manage this problem, though adoption rates are low. A mail survey was conducted to determine differences between adopter and nonadopter characteristics and attitudes with regard to the use of RFBs. Data were collected from 48 RFB adopters and 261 RFB nonadopters in two Nebraska watersheds. Inferential and multivaririate statistics were used to identify differences between adapter status and producer status groups. About half (50.8%) the respondents were nonproducers. Nonproducers are agricultural landowners not farming that make decisions about whether to install conservation practices on their land. Among the adopter respondents, non-farming agricultural landowners (nonproducers, n=25) were as likely to adopt RFHs as producers (n=23). Adopters were more informed about RFBs and willing to accept government payments. Receiving technical and financial assistance was a major key to adoption. The research has identified important opportunities for more effective and targeted RFB extension education programming

    White-tailed Deer Browsing and Rubbing Preferences for Trees and Shrubs That Produce Nontimber Forest Products

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    Nontimber forest products (food, herbal medicinals, and woody floral and handicraft products) produced in forest, agroforestry, and horticultural systems can be important sources of income to landowners. White-tailed deer (Odocoileus virginianus) can reduce the quality, quantity, and profitability of forest products by browsing twigs and rubbing stems, resulting in direct and indirect losses to production enterprises. We evaluated deer damage (frequency and intensity of browsing and rubbing) sustained by 26 species of trees and shrubs, the relationships among morphological features of trees and shrubs to damage levels, and the economic impacts of deer damage on the production of nontimber forest products. Levels of browsing were high (frequency \u3e93% and intensity \u3e50%) in most species of trees and shrubs, with the highest intensity (\u3e60%) occurring in chinese chestnut (Castanea mollisima) and dogwood (Cornus spp.), and the lowest (Ginkgo biloba), curly willow (Salix matsudana), ‘Scarlet Curls’ curly willow, smooth sumac (Rhus glabra), and pussy willow (Salix caprea). Species of trees or shrubs with one or a few stout stems unprotected by dense branching [e.g., american elderberry (Sambucus canadensis), smooth sumac, and curly willow] sustained the most damage by rubbing. Trees and shrubs with many small diameter stems or with dense tangled branching [e.g. redozier dogwood (Cornus sericea), forsythia (Forsythia suspensa), ‘Flame’ willow (Salix alba), and ‘Streamco’ basket willow (Salix purpurea)] were damaged the least by rubbing. Annual economic costs of deer damage to producers of nontimber forest products can range from 26/acreforpussywillowto26/acre for pussy willow to 1595/acre for curly willow

    Long-rising Type II Supernovae in the Zwicky Transient Facility Census of the Local Universe

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    SN 1987A was an unusual hydrogen-rich core-collapse supernova originating from a blue supergiant star. Similar blue supergiant explosions remain a small family of events, and are broadly characterized by their long rises to peak. The Zwicky Transient Facility (ZTF) Census of the Local Universe (CLU) experiment aims to construct a spectroscopically complete sample of transients occurring in galaxies from the CLU galaxy catalog. We identify 13 long-rising (>40 days) Type II supernovae from the volume-limited CLU experiment during a 3.5 year period from June 2018 to December 2021, approximately doubling the previously known number of these events. We present photometric and spectroscopic data of these 13 events, finding peak r-band absolute magnitudes ranging from -15.6 to -17.5 mag and the tentative detection of Ba II lines in 9 events. Using our CLU sample of events, we derive a long-rising Type II supernova rate of 1.37−0.30+0.26×10−61.37^{+0.26}_{-0.30}\times10^{-6} Mpc−3^{-3} yr−1^{-1}, ≈\approx1.4% of the total core-collapse supernova rate. This is the first volumetric rate of these events estimated from a large, systematic, volume-limited experiment.Comment: 32 pages, 17 figures, 5 tables. Submitted to Ap

    NR4A Gene Expression Is Dynamically Regulated in the Ventral Tegmental Area Dopamine Neurons and Is Related to Expression of Dopamine Neurotransmission Genes

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    The NR4A transcription factors NR4A1, NR4A2, and NR4A3 (also known as Nur77, Nurr1, and Nor1, respectively) share similar DNA-binding properties and have been implicated in regulation of dopamine neurotransmission genes. Our current hypothesis is that NR4A gene expression is regulated by dopamine neuron activity and that induction of NR4A genes will increase expression of dopamine neurotransmission genes. Eticlopride and γ-butyrolactone (GBL) were used in wild-type (+/+) and Nurr1-null heterozygous (+/−) mice to determine the mechanism(s) regulating Nur77 and Nurr1 expression. Laser capture microdissection and real-time PCR was used to measure Nurr1 and Nur77 mRNA levels in the ventral tegmental area (VTA). Nur77 expression was significantly elevated 1 h after both GBL (twofold) and eticlopride (fourfold). In contrast, GBL significantly decreased Nurr1 expression in both genotypes, while eticlopride significantly increased Nurr1 expression only in the +/+ mice. In a separate group of mice, haloperidol injection significantly elevated Nur77 and Nor1, but not Nurr1 mRNA in the VTA within 1 h and significantly increased tyrosine hydroxylase (TH) and dopamine transporter (DAT) mRNA expression by 4 h. These data demonstrate that the NR4A genes are dynamically regulated in dopamine neurons with maintenance of Nurr1 expression requiring dopamine neuron activity while both attenuation of dopamine autoreceptors activation and dopamine neuronal activity combining to induce Nur77 expression. Additionally, these data suggest that induction of NR4A genes could regulate TH and DAT expression and ultimately regulate dopamine neurotransmission
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