9 resultados para lead isotopes
em DigitalCommons@University of Nebraska - Lincoln
Resumo:
“Nearly all men can stand adversity, but if you want to test a man’s character give him power.” That quote, by my hero Abraham Lincoln, is one I think all leaders should remember and reflect on regularly in their life, and so I pass it on to each of you. I wish each member of this LEAD group the character to use power wisely, with compassion and integrity, and a strong-sense of justice and fair play.
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Good morning. I am delighted to be with you here this morning to offer my congratulations and my best wishes as you complete the LEAD program. This is a wonderful and significant accomplishment, and I certainly hope you all are celebrating and savoring it. I look forward with enthusiasm to watching your future contributions as leaders in agriculture, in your local communities, in Nebraska, and in our global community. I'd like to start my remarks this morning with one question: How many people in this room have ridden an elephant? Show of hands?
Resumo:
A CURRENT EXAMINATION OF DIETARY INTAKES OF FIBER, CALCIUM, IRON, AND ZINC AND THEIR RELATIONSHIP TO BLOOD LEAD LEVELS IN U.S. CHILDREN AGED 1-5 YEARS Stephanie Ann Melchert, M.S. University of Nebraska, 2010 Adviser: Kaye Stanek Krogstrand The effect of lead on the health and well-being of those exposed has been well documented and many efforts have been made to reduce exposure of lead to the United States population. Despite these efforts, many studies have documented cognitive impairments and behavioral problems in children with even low levels of lead in their blood. Previous studies have suggested that a proper diet may have a role in the prevention of elevated blood lead levels in children. The objective of this study was to determine if there was an inverse correlation of blood lead levels (BLL) in children to their dietary intakes of fiber, calcium, iron, and zinc considering low levels of lead exposure. This study examined 1019 children in the National Health and Nutrition Examination Survey (NHANES) conducted from 2005-2006. Data were analyzed using Spearman’s rank correlations to correlate continuous variables to BLL in children and independent samples t-tests were used to compare mean blood lead levels of categorical variables. Results indicate that BLL in children is significantly correlated with and weight, recumbent length/standing height, dietary fiber intake and continine, a marker of cigarette smoke exposure. BLL was not significantly correlated with calcium, iron, zinc, or vitamin C. A significant difference was found in the mean BLL of children who took supplements, lived in smoking homes, as well as those who lived in homes built before 1978. Overall, this study shows that children living in homes built before 1978 remain at greater risk for lead exposure, and adequate dietary fiber intake may provide benefits to children who are exposed to lead.
Resumo:
Thank you for inviting us to share with you some information about the Institute of Agriculture and Natural Resources, and what we are doing for Nebraska. As a stakeholder in Nebraska's land-grant university, you and every other Nebraskan have every right at any time to ask us what we've done for you and your neighbors lately. We welcome the question. There is so much excellent work being accomplished on this campus and throughout Nebraska that I am delighted each time I have the opportunity to talk about it. The biggest problem I find is stopping - there's always so much more to say - than there is time to say it in!
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Folks, we're just delighted to have you on campus with us, and I greatly appreciate this opportunity to speak with you.
Resumo:
Good afternoon, everyone. Those of us representing the Institute of Agriculture and Natural Resources are pleased to be here with you today. We welcome you to IANR Shout It Out, the exciting Institute of Agriculture and Natural Resources game that allows you to test your IANR and Nebraska knowledge, learn exciting new facts, and most importantly of all win prizes!
Resumo:
Let me begin today by offering my congratulations to each of you who is a member of this new LEAD class. You are embarking upon a truly exciting, rewarding opportunity, important to both you and Nebraska. Our state needs good leaders, people dedicated to keeping our organizations, communities, and Nebraska strong, and moving forward. We need leaders of courage and compassion, able to think clearly, assess information, formulate a plan, and adjust that plan as needed. We need leaders who work toward a common good.
Resumo:
Grassland ecosystems have been severely reduced and grassland bird populations have experienced consistent declines. National Park Service (NPS) properties on the Great Plains provide breeding habitat for grassland songbirds, though little is known about the quality of this habitat. A short-term study on songbirds at three NPS properties complemented current monitoring, providing an among park comparison addressing grassland bird productivity and fidelity relative to NPS property size. During 2008-2009, I assessed avian species richness, and estimated bird density and grassland songbird nest success. Bird species richness was greatest at small and medium sites, while number of nesting obligate species was greatest at the large site. Species-specific densities varied among sites, with few grassland obligates occurring at all three sites. Nest success estimates for grassland obligates were highest at the small site and lower at the large site. Another method to quantify habitat quality is assessment of breeding site fidelity. Current extrinsic markers used in monitoring site fidelity are inadequate for small birds; stable isotope analyses provide an alternative. I compared two techniques for assigning stable isotope tissue origin and measured grassland songbird site fidelity. My method of assigning origin provided site-specific variances of expected stable isotope values, an improvement over the most commonly used method. Fidelity tended to be higher at the large site, which may indicate a more robust breeding community of grassland birds. The small size of two of my sites precluded large sample sizes and made strong inferences difficult. To quantify how scientists cope with weak inference, I conducted a literature review. Strong inference was rarely observed, and most authors of weak-inference papers provided specific management recommendations. I suggest that adaptive management is an ideal method to resolve uncertainty from weak inference. Managers should consider my results within the context of regional and global management and the extent to which their unit might aide songbird conservation.
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The wetlands of south-central Nebraska’s Rainwater Basin region are considered of international importance as a habitat for millions of migratory birds, but are being endangered by agricultural practices. The Rainwater Basin extends across 17 counties and covers 4,000 square miles. The purpose of this study was to assemble baseline chemical data for several representative wetlands across the Rainwater Basin region, and determine the use of these chemical data for investigating groundwater recharge. Eight representative wetlands were chosen across the Rainwater Basin to monitor surface and groundwater chemistry. At each site, a shallow well and deep well were installed and sampled once in the summer of 2009 and again in the spring of 2010. Wetland surface water was sampled monthly from April, 2009 to May, 2010. Waters were analyzed for major ions, nutrients, pesticides and oxygen-18 and deuterium isotopes at the University of Nebraska Water Sciences Laboratory. Geochemical analysis of surface waters presents a range of temporal and spatial variations. Wetlands had variable water volumes, isotopic compositions, ion chemistries and agricultural contaminant levels throughout the year and, except for a few trends, theses variations cannot be predicted with certainty year-to-year or wetland-to-wetland. Isotopic compositions showed evaporation was a contributor to water loss, and thus, did impact water chemistry. Surface water nitrate concentrations ranged from <0.10 to 4.04 mg/L. The nitrate levels are much higher in the groundwater, ranging from <0.10 to 18.4 mg/L, and are of concern because they are found above the maximum contaminant level (MCL) of 10 mg/L. Atrazine concentrations in surface waters ranged from <0.05 to 10.3 ppb. Groundwater atrazine concentrations ranged from <0.05 to 0.28 ppb. The high atrazine concentrations in surface waters are of concern as they are above the MCL of 3 ppb, and the highest levels occur during the spring bird migration. Most sampled groundwaters had detectable tritium indicating a mix of modern (<5 to 10 years old) and submodern (older than 1950s) recharge. The groundwater also had differences in chemical and isotope composition, and in some cases, increased nitrate concentrations, between the two sampling periods. Modern groundwater tritium ages and changes in groundwater chemical and isotopic compositions may indicate connections with surface waters in the Rainwater Basin.