198 research outputs found

    History of nutrient inputs to the northeastern United States, 1930–2000

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    Humans have dramatically altered nutrient cycles at local to global scales. We examined changes in anthropogenic nutrient inputs to the northeastern United States (NE) from 1930 to 2000. We created a comprehensive time series of anthropogenic N and P inputs to 437 counties in the NE at 5 year intervals. Inputs included atmospheric N deposition, biological N2 fixation, fertilizer, detergent P, livestock feed, and human food. Exports included exports of feed and food and volatilization of ammonia. N inputs to the NE increased throughout the study period, primarily due to increases in atmospheric deposition and fertilizer. P inputs increased until 1970 and then declined due to decreased fertilizer and detergent inputs. Livestock consistently consumed the majority of nutrient inputs over time and space. The area of crop agriculture declined during the study period but consumed more nutrients as fertilizer. We found that stoichiometry (N:P) of inputs and absolute amounts of N matched nutritional needs (livestock, humans, crops) when atmospheric components (N deposition, N2 fixation) were not included. Differences between N and P led to major changes in N:P stoichiometry over time, consistent with global trends. N:P decreased from 1930 to 1970 due to increased inputs of P, and increased from 1970 to 2000 due to increased N deposition and fertilizer and decreases in P fertilizer and detergent use. We found that nutrient use is a dynamic product of social, economic, political, and environmental interactions. Therefore, future nutrient management must take into account these factors to design successful and effective nutrient reduction measures

    IUPHAR-DB: An Expert-Curated, Peer-Reviewed Database of Receptors and Ion Channels

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    The International Union of Basic and Clinical Pharmacology database (IUPHAR-DB) integrates peer-reviewed pharmacological, chemical, genetic, functional and anatomical information on the 354 non-sensory G protein-coupled receptors (GPCRs), 71 ligand-gated ion channel subunits and 141 voltage-gated ion channel subunits encoded by the human, rat and mouse genomes. These genes represent the targets of about a third of currently approved drugs and are a major focus of drug discovery and development programs in the pharmaceutical industry. Individual gene pages provide a comprehensive description of the genes and their functions, with information on protein structure, ligands, expression patterns, signaling mechanisms, functional assays and biologically important receptor variants (e.g. single nucleotide polymorphisms and splice variants). The phenotypes resulting from altered gene expression (e.g. in genetically altered animals) and genetic mutations are described. Links are provided to bioinformatics resources such as NCBI RefSeq, OMIM, PubChem, human, rat and mouse genome databases. Recent developments include the addition of ligand-centered pages summarising information about unique ligand molecules in IUPHAR-DB. IUPHAR-DB represents a novel approach to biocuration because most data are provided through manual curation of published literature by a network of over 60 expert subcommittees coordinated by NC-IUPHAR. Data are referenced to the primary literature and linked to PubMed. The data are checked to ensure accuracy and consistency by the curators, added to the production server using custom-built submission tools and peer-reviewed by NC-IUPHAR, before being transferred to the public database. Data are reviewed and updated regularly (at least biennially). Other website features include comprehensive database search tools, online and downloadable gene lists and links to recent publications of interest to the field, such as reports on receptor-ligand pairings. The database is freely available at "http://www.iuphar-db.org":http://www.iuphar-db.org. Curators can be reached at curators [at] iuphar-db.org. We thank British Pharmacological Society, UNESCO (through the ICSU Grants Programme), Incyte, GlaxoSmithKline, Novartis, Servier and Wyeth for their support

    A Scale-Explicit Framework for Conceptualizing the Environmental Impacts of Agricultural Land Use Changes

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    Demand for locally-produced food is growing in areas outside traditionally dominant agricultural regions due to concerns over food safety, quality, and sovereignty; rural livelihoods; and environmental integrity. Strategies for meeting this demand rely upon agricultural land use change, in various forms of either intensification or extensification (converting non-agricultural land, including native landforms, to agricultural use). The nature and extent of the impacts of these changes on non-food-provisioning ecosystem services are determined by a complex suite of scale-dependent interactions among farming practices, site-specific characteristics, and the ecosystem services under consideration. Ecosystem modeling strategies which honor such complexity are often impenetrable by non-experts, resulting in a prevalent conceptual gap between ecosystem sciences and the field of sustainable agriculture. Referencing heavily forested New England as an example, we present a conceptual framework designed to synthesize and convey understanding of the scale- and landscape-dependent nature of the relationship between agriculture and various ecosystem services. By accounting for the total impact of multiple disturbances across a landscape while considering the effects of scale, the framework is intended to stimulate and support the collaborative efforts of land managers, scientists, citizen stakeholders, and policy makers as they address the challenges of expanding local agriculture

    MIGHTEE: multi-wavelength counterparts in the COSMOS field

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    In this paper, we combine the Early Science radio continuum data from the MeerKAT International GHz Tiered Extragalactic Exploration (MIGHTEE) Survey, with optical and near-infrared data and release the cross-matched catalogues. The radio data used in this work covers 0.86 deg2 of the COSMOS field, reaches a thermal noise of 1.7 μJy beam−1 and contains 6102 radio components. We visually inspect and cross-match the radio sample with optical and near-infrared data from the Hyper Suprime-Cam (HSC) and UltraVISTA surveys. This allows the properties of active galactic nuclei and star-forming populations of galaxies to be probed out to z ≈ 5. Additionally, we use the likelihood ratio method to automatically cross-match the radio and optical catalogues and compare this to the visually cross-matched catalogue. We find that 94 per cent of our radio source catalogue can be matched with this method, with a reliability of 95 per cent. We proceed to show that visual classification will still remain an essential process for the cross-matching of complex and extended radio sources. In the near future, the MIGHTEE survey will be expanded in area to cover a total of ∼20 deg2; thus the combination of automated and visual identification will be critical. We compare the redshift distribution of SFG and AGN to the SKADS and T-RECS simulations and find more AGN than predicted at z ∼ 1

    Riparian Plant Isotopes Reflect Anthropogenic Nitrogen Perturbations: Robust Patterns Across Land Use Gradients

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    Riparian plants incorporate nitrogen (N) from aquatic, terrestrial, and atmospheric sources, and their stable isotope compositions (δ15 N) may reflect land use impacts on N sources and transformations over scales of sites to watersheds. We surveyed leaf δ15 N values of 11 common riparian tree, shrub, and herbaceous species from 20 streams and rivers spanning three fifth-order watersheds in northern Utah, USA (n - 255 sites and 819 leaf samples). Streams spanned undeveloped montane forests to suburban, urban, and agricultural lands. Mean species-specific differences in leaf δ15N values were relatively small within sites (1.2 ± 2.2‰), although emergent aquatic macrophytes had higher within-site δ15 N values than other growth forms. Leaf δ15 N values varied significantly across land-use categories, and were lowest in undeveloped montane reaches (0.5 ± 1.9‰; mean and standard deviation), intermediate in suburban and urban reaches (2.3 ± 2.6 and 3.2 ± 3.4‰), and greatest in agricultural reaches (4.1 ± 3.1‰). The substantial variation in leaf δ15N values within a land use category often corresponded with local management differences. In an undeveloped montane canyon permitting off-leash dogs, leaf δ15N values (1.5 ± 1.3‰) exceeded similar canyons that strictly prohibited dogs (δ15 N = - 0.7 ± 1.1‰). Canyons with cattle grazing had leaf δ15 N values enriched by 1.4 and 2.8‰ relative to similar, but un-grazed canyons. Variation in traffic between 0 and 5000 vehicles per day did not significantly affect leaf δ15N values, although a canyon with 50,000 vehicles per day showed a 5.7‰ increase relative to low-trafficked canyons. Urban leaf δ15N values were consistently enriched by 2.5 ± 0.6‰ relative to leaves in un-grazed montane reaches, and leaves in a septic-impacted suburban reach were enriched by 4.6‰ relative to upstream samples. Samples from a sewage-impacted urban river averaged 8.0 ± 4.1‰ and reached 22‰ adjacent to publicly owned treatment works (POTW). Another urban river displayed similar values in the absence of POTWs, implicating leaky sewers. Our results demonstrate the capacity of N isotopes from a diverse riparian plant community to inform our spatial understanding of watershed N-cycling perturbations, and illustrate the impact of human activities on N cycling even within protected watersheds. © 2015 Hall et al

    Endocannabinoid metabolism inhibition has no effect on spontaneous fear recovery or extinction resistance in Lister hooded rats

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    Endocannabinoid transmission is emerging as a target for treating anxiety-related disorders, given its regulation of fear extinction. Boosting anandamide levels via inhibition of its metabolism by fatty acid amide hydrolase (FAAH) can enhance extinction, whereas inhibiting monoacylglycerol lipase (MAGL) to elevate 2-arachidonoylglycerol levels can impair extinction. However, whether endocannabinoids regulate fear relapse over time or extinction resistance remains unclear. In two experiments using auditory fear conditioned rats, we examined the effects of the FAAH inhibitor URB597 and the MAGL inhibitor JZL184 administered systemically on 1) spontaneous fear recovery after delayed extinction, and 2) extinction resistance resulting from immediate extinction [the immediate extinction deficit (IED)]. In Experiment 1, URB597 or JZL184 was given immediately after delayed extinction occurring 24 h after conditioning. Extinction recall and spontaneous fear recovery were tested drug-free 1 and 21 days later, respectively. We found no effects of either drug on extinction recall or spontaneous fear recovery. In Experiment 2, URB597 or JZL184 was given before immediate extinction occurring 30 min after conditioning and extinction recall was tested drug-free the next day. We also examined the effects of propranolol, a beta-adrenoceptor antagonist that can rescue the IED, as a positive control. JZL184 enhanced fear expression and impaired extinction learning but we found no lasting effects of URB597 or JZL184 on cued extinction recall. Propranolol reduced fear expression but, unexpectedly, had no enduring effect on extinction recall. The results are discussed in relation to various methodological differences between previous studies examining endocannabinoid and adrenergic regulation of fear extinction

    Explorations, Vol. 6, No. 1

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    Cover: Panthera pardus, Chui in Kiswatuli, was photographed by Dr. Linda Karbonit ar Dr. James A. Sherburne in Serengeti National Park, Tanzania. Karbonit was accompanying Sherburne who was working on the design and development of the University of Maine, U.S. Fish and Wildlife Service, assistance program in wildlife training and conservation education to Tanzania’s National Parks. Sherburne, who has worked in Tanzania for several years, was there most recently in 1988 and 1989 working on the parks project. He serves as the Director of International Natural Resources and Agricultural Programs at the University of Maine. Articles include: Research and Economic Development: from the U.S. Senate Statement, December 22, 1989, by Sen. George J. Mitchell Politics and Research: Providing a Key for Economic Development, by Sen. William S. Cohen. Publisher’s Perspective, by Gregory N. Brown, Vice President, Research and Public Service What’s EPSCoR? Editorial Reflections, by Carole J. Bombard Past and Present: Marine Geologists Explore the Old and Teach the Young, by Daniel Belknap and Joseph Kelley High Biological Productivity: Salt Marshes, by Mark E. Wood Barrier Beaches, by William Duffy Sediment Budgets & Bluff Slump, by Rebecca Smith Coastal Environments and Change, by Andrew Walsh Mapping What You Can\u27t See, by Donald Robbins Casco Bay: Sea Level and the Shoreline, by Bradley W.B. Hay Christmas at Sea, by Molly Horvath A Short Course and the Local Economy, by Richard Hale and James Philp Dr. Bernard Lown: Alumnus Receives Golden Door Award The Sky is Falling . . . well, maybe, by Carole J. Bombard A Growing Interest in Timberland, by Robert A. Strong and Bret P. Vicar

    Community-powered urban stream restoration: A vision for sustainable and resilient urban ecosystems

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    Urban streams can provide amenities to people living in cities, but those benefits are reduced when streams become degraded, potentially even causing harm (disease, toxic compounds, etc.). Governments and institutions invest resources to improve the values and services provided by urban streams; however, the conception, development, and implementation of such projects may not include meaningful involvement of community members and other stakeholders. Consequently, project objectives may be misaligned with community desires and needs, and projects may fail to achieve their goals. In February 2020, the 5(th) Symposium on Urbanization and Stream Ecology, an interdisciplinary meeting held every 3 to 5 y, met in Austin, Texas, USA, to explore new approaches to urban stream projects, including ways to maximize the full range of potential benefits by better integrating community members into project identification and decision making. The symposium included in-depth discussion about 4 nearby field case studies, participation of multidisciplinary urban stream experts from 5 continents, and input from the Austin community. Institutional barriers to community inclusion were identified and analyzed using real-world examples, both from the case studies and from the literature, which clarified disparities in power, equity, and values. Outcomes of the symposium have been aggregated into a vision that challenges the present institutional approach to urban stream management and a set of strategies to systematically address these barriers to improve restoration solutions. Integrating community members and other stakeholders throughout the urban restoration process, and a transparent decision-making process to resolve divergent objectives, can help identify appropriate goals for realizing both the ecological and social benefits of stream restoration
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