236 research outputs found

    Targeting Agricultural Drainage to Reduce Nitrogen Losses in a Minnesota Watershed

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    Agricultural nitrogen losses are the major contributor to nitrogen loads in the Mississippi River, and consequently, to the existence of a hypoxic, or dead, zone in the Gulf of Mexico. Focusing on two small agricultural watersheds in southeast Minnesota, simulation results from the Agricultural Drainage And Pesticide Management (ADAPT) model were combined with a linear-optimization model to evaluate the environmental and economic impact of alternative land-use policies for reducing nitrogen losses. Of particular importance was the studys explicit focus on agricultural subsurface (tile) drainage, which has been identified as the major pathway for agricultural nitrogen losses in the upper Midwest, and the use of drainage-focused abatement policies. Results indicate that tile-drained land plays a key role in nitrogen abatement, and that a combined policy of nutrient management on tile-drained land and retirement of non-drained land is a cost-effective means of achieving a 20- or 30-percent nitrogen-abatement goal. Results also indicate that although it is cost-effective to abate on tile-drained land, it is not cost-effective to undertake policies that plug or remove tile drains from the landscape, regardless of whether the land would be retired or kept in production. Therefore, results imply that although tile-drained land is a major source of nitrogen lost to waterways, it is not cost-effective to remove the land from production or to remove the drainage from the land. Because of its value to agricultural production, it is better to keep tile-drained land in production under nutrient management and focus retirement policies on relatively less-productive, non-drained acres.Environmental Economics and Policy, Land Economics/Use,

    Economic and Environmental Impacts of Cellulosic Feedstock Production in Minnesota

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    Crop Production/Industries, Environmental Economics and Policy, Production Economics,

    Landlabs: An Integrated Approach to Creating Agricultural Enterprises That Meet the Triple Bottom Line

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    Global demand is increasing for food, feed, and fiber; for additional agricultural outputs, such as biofuels; and for ecosystem services, such as clean water and outdoor recreation. In response, new agricultural enterprises are needed that produce more outputs from existing lands while meeting the triple bottom line of high performance in economic, environmental, and social terms. Establishing such enterprises requires coordination and development within three critical domains: landscape configurations (i.e., types and arrangements of land uses), supply/value chains (i.e., processing and utilization), and policy and governance. In this essay, we describe our efforts, as land-grant university scientists, to support coordinated innovation and enterprise development in integrated place-based institutions, which we term landlabs. We describe our experiences in three prototyping efforts and outline key features of landlabs that are emerging from these efforts. Land-grant universities have a central and crucial role to play in organizing and operating landlabs

    Late onset vitamin K deficiency bleeding, extreme prematurity and a human milk based diet

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    An extremely preterm female infant (born at 23+5 weeks; weight 555g) received 0.4mg/kg IM Vitamin K1 (VK). She received an exclusively human milk-based diet and was commenced on a commercially available human-milk fortifier

    Simulating the effect of perennialized cropping systems on nitrate-N losses using the SWAT model

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    Several newly released crop varieties, including the perennial intermediate wheatgrass (grain marketed as Kernza®), and the winter hardy oilseed crop camelina, have been developed to provide both economic return for farmers and reduced nutrient losses from agricultural fields. Though studies have indicated that these crops could reduce nitrate-nitrogen (N) leaching, little research has been done to determine their effectiveness in reducing nitrate-N loading to surface waters at a watershed scale, or in comparing their performance to more traditional perennial crops, such as alfalfa. In this study, nitrate-N losses were predicted using the Soil and Water Assessment Tool (SWAT) model for the Rogers Creek watershed located in south-central Minnesota, USA. Predicted looses of nitrate-N under three perennialized cropping systems were compared to losses given current cropping practices in a corn (Zea mays L.)-soybean (Glycine max L. Merr.) rotation. The perennialized systems included three separate crop rotations: intermediate wheatgrass (IWG) in rotation with soybean, alfalfa in rotation with corn, and winter camelina in rotation with soybean and winter rye. Model simulation of these rotations required creation of new crop files for IWG and winter camelina within SWAT. These new crop files were validated using measured yield, biomass, and nitrate-N data. Model results show that the IWG and alfalfa rotations were particularly effective at reducing nutrient and sediment losses from agricultural areas in the watershed, but smaller reductions were also achieved with the winter camelina rotation. From model predictions, achieving regional water-quality goals of a 30% reduction in nitrate-N load from fields in the watershed required converting approximately 25, 34, or 57% of current corn-soybean area to the alfalfa, IWG, or camelina rotations, respectively. Results of this study indicate that adoption of these crops could achieve regional water quality goals

    Exclusively breastmilk‐fed preterm infants are at high risk of developing subclinical vitamin K deficiency despite intramuscular prophylaxis at birth

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    Background: There is near-global consensus that all newborns be given parenteral vitamin K1 (VK1) at birth as prophylaxis against VK deficiency bleeding (VKDB). Breastmilk has a low VK content and cases of late VKDB are reported in exclusively breastmilk-fed preterm infants despite VK prophylaxis at birth. Objectives: To assess the prevalence of functional VK insufficiency in preterm infants based on elevated under-γ-carboxylated (Glu) species of Gla-proteins, factor II (PIVKA-II) and osteocalcin (GluOC), synthesized by liver and bone respectively. Patients/Methods: Prospective, multi-center, observational study in preterm infants born <33 weeks’ gestation. Blood samples and dietary history were collected before hospital discharge, and post discharge at 2-3 months corrected age. Outcome measures were serum VK1, PIVKA-II, and %GluOC (GluOC as a percentage of the sum of GluOC plus GlaOC) compared between exclusively breastmilk-fed and formula/mixed-fed infants post-discharge. Results: Post discharge, breastmilk-fed babies had significantly lower serum VK1 (0.15 vs. 1.81 μg/L), higher PIVKA-II (0.10 vs. 0.02 AU/mL) and higher %GluOC (63.6% vs. 8.1%) than those receiving a formula/mixed-feed diet. Pre-discharge (based on elevated PIVKA-II), only 1 (2%) of 45 breastmilk-fed infants was VK insufficient. Post-discharge, 8 (67%) of 12 exclusively breastmilk-fed babies were VK insufficient versus only 1 (4%) of 25 formula/mixed-fed babies. Conclusions: Preterm infants who remain exclusively or predominantly human breastmilk-fed post neonatal unit discharge are at high risk of developing subclinical VK deficiency in early infancy. Routine post-discharge VK1 supplementation of breastfed infants to provide intakes comparable to those from formula milks should prevent this deficiency

    Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead.

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    Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis. Only 15% (13/85) were found to have evidence of a dose-response threshold, whereas 59% (50/85) exerted low-dose effects. No dose-response information was found for the remaining 26% (22/85). Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies. Additional basic research on carcinogenesis and research focused on low-dose effects of chemical mixtures needs to be rigorously pursued before the merits of this hypothesis can be further advanced. However, the structure of the World Health Organization International Programme on Chemical Safety 'Mode of Action' framework should be revisited as it has inherent weaknesses that are not fully aligned with our current understanding of cancer biology
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