897 research outputs found

    Nitrogen in Surface Water and Groundwater a EKU’s Meadowbrook Farm

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    Agricultural activities often contaminate watersheds with excess nutrients leading to poor water quality and eutrophication. Eastern Kentucky University’s Meadowbrook Farm, contributes dissolved nitrogen into the Muddy Creek watershed. To assess the concentrations of dissolved nitrogen compounds, we sampled waters draining from the Farm as springs, runoff, and subsurface pipe drainage as well as Muddy Creek on six days from May to August 2016 under a variety of weather conditions. We measured dissolved nitrate (NO3-) and ammonium (NH4+) using standard colorimetric methods and spectrophotometry with an accuracy of ~0.1 mg/L. Nitrate was the dominant nutrient contaminant, whereas ammonium was often absent in water samples. Nitrate levels were usually/L in surface waters. Springs and some tributaries exhibited the largest nitrate values generally ranging from 7.0 to 14.3 mg/L. Ammonium displayed sporadic concentration spikes between 2.0 and 4.3 mg/L. Dissolved nitrogen concentrations responded to rainfall. We saw a general decrease of nitrogen concentration during dry periods, especially in Muddy Creek and an increase in nitrogen concentration under wetter conditions. Springs maintained high nitrogen concentrations regardless of different rainfall conditions. We compared our nitrogen measurements from Meadowbrook Farm to national values. For surface waters, the median nitrate concentration was 2.7 mg/L, lower than the national median (3.8 mg/L), whereas ammonium values were 0.2 mg/L, higher than the national median (0.1 mg/L). In groundwater, we found the median nitrate concentration was 3.9 mg/L, higher than the national median (3.4 mg/L), whereas the median ammonium concentration was 0.05 mg/L, higher than the national median (0.02 mg/L)

    GEOCHEMISTRY OF SURFACE WATERS AND GROUNDWATER AT EKU’S MEADOWBROOK FARM, MADISON COUNTY, KENTUCKY

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    Agricultural activities often contaminate watersheds with excess nutrients leading to poor water quality and eutrophication. Eastern Kentucky University (EKU) Meadowbrook Farm raises crops and livestock, which contribute dissolved nutrients to the neighboring Muddy Creek watershed. Our goal is to understand Farm water geochemistry to develop methods to sequester phosphorous and limit nutrient contamination. During the Cindy storm event, concentration of Ca2+, Mg2+, and Na+ within baseline source waters decreased with increasing discharge through the weir. This behavior represents dilution of Farm groundwater by storm precipitation. However, K+ spiked concurrently with increased discharge then progressively decreased over the duration of the storm, suggesting that K+ was flushed from soil by rain waters. Nutrient concentrations generally increase with increased discharge indicating transport by surface runoff. PO43- closely tracks discharge, suggesting PO43- transport from the surficial soil substrate via flushing by precipitation. NO3- exhibited nearly identical transport behavior as K+, however NO3- levels reached a higher baseline concentration than pre-storm levels. This suggests infiltration and retention of NO3- within soil and groundwater during fair weather, initial flushing during the rain event, and then prolonged NO3- release from Farm soil and groundwater. NH4+ immediately increases with the first rainfall then decreases to levels slightly above background. This behavior suggests rapid release of NH4+ from soil followed by accumulation within the weir pool and then subsequent flushing during the precipitation event

    Nutrient contamination from non-point sources: Dissolved nitrate and ammonium in surface and subsurface waters at EKU Meadowbrook Farm, Madison County, Kentucky

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    Agricultural activities often contaminate watersheds with excess nutrients leading to poor water quality and eutrophication. Eastern Kentucky University’s Meadowbrook Farm, contributes dissolved nitrogen into the Muddy Creek watershed. To assess the concentrations of dissolved nitrogen compounds, we sampled waters draining from the Farm as springs, runoff, and subsurface pipe drainage as well as Muddy Creek on six days from May to August 2016 under a variety of weather conditions. We measured dissolved nitrate (NO­3-) and ammonium (NH4+) using standard colorimetric methods and spectrophotometry with an accuracy of ~0.1 mg/L. Nitrate was the dominant nutrient contaminant, whereas ammonium was often absent in water samples. Nitrate levels were usually \u3c2 mg/L in surface waters. Springs and some tributaries exhibited the largest nitrate values generally ranging from 7.0 to 14.3 mg/L. Ammonium displayed sporadic concentration spikes between 2.0 and 4.3 mg/L. Dissolved nitrogen concentrations responded to rainfall. We saw a general decrease of nitrogen concentration during dry periods, especially in Muddy Creek and an increase in nitrogen concentration under wetter conditions. Springs maintained high nitrogen concentrations regardless of different rainfall conditions. We compared our nitrogen measurements from Meadowbrook Farm to national values. For surface waters, the median nitrate concentration was 2.7 mg/L, lower than the national median (3.8 mg/L), whereas ammonium values were 0.2 mg/L, higher than the national median (0.1 mg/L). In groundwater, we found the median nitrate concentration was 3.9 mg/L, higher than the national median (3.4 mg/L), whereas the median ammonium concentration was 0.05 mg/L, higher than the national median (0.02 mg/L)

    Variability of contour line alignment on sequential images with the Heidelberg Retina Tomograph

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    •Background: The influence of the contour line alignment software algorithm on the variability of the Heidelberg Retina Tomograph (HRT) parameters remains unclear. •Methods: Nine discrete topographic images were acquired with the HRT from the right eye in six healthy, emmetropic subjects. The variability of topometric data obtained from the same topographic image, analyzed within different samples of images, was evaluated. A total of four mean topographic images was computed for each subject from: all nine discrete images (A), the first six of those images (B), the last six of those nine images (C), and the first three combined with the last three images (D). A contour line was computed on the mean topographic image generated from the nine discrete topographic images (A). This contour line was then applied to the three other mean topographic images (B, C, and D), using the contour line alignment in the HRT software. Subsequently, the contour line on the mean topographic images was applied to each of the discrete members of the particular images subsets used to compute the mean topographic image, and the topometric data for these discrete topographic images was computed successively for each subset. Prior to processing each subset, the contour line on the discrete topographic images was deleted. This strategy provided a total of three analyses on each discrete topographic image: as a member of the nine images (mean topographic image A), and as a member of two subsets of images (mean topographic image B, C, and/or D). The coefficient of variation (100×SD/mean) of the topographic parameters within those three analyses was calculated for each discrete topographic image in each subject ("intraimage” coefficient of variation). In addition, a coefficient of variation between the nine discrete topographic images ("interimage” coefficient of variation) was calculated. •Results: The "intraimage” and "interimage” variability for the various topographic parameters ranged between 0.03% and 3.10% and between 0.03% and 24.07% respectively. The "intraimage” coefficients of variation and "interimage” coefficients of variation correlated significant (r 2=0.77;P<0.0001). •Conclusion: A high "intraimage” variability, i.e. a high variability in contour line alignment between sequential images, might be an important source of test re-test variability between sequential image

    Geochemical Characteristics and Storm Dynamics of Surface Waters and Groundwater at Eastern Kentucky University’s Meadowbrook Farm, Madison County, Kentucky

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    Agricultural activities often contaminate watersheds with excess nutrients leading to poor water quality and eutrophication. Eastern Kentucky University’s Meadowbrook Farm raises crops and livestock, contributing dissolved nutrients to the neighboring Muddy Creek watershed. Consequently, the Farm is developing methods to sequester and limit nutrient contamination. Before phosphorous sequestration methods can be tested, the geochemistry of surface water and groundwater on the Farm need to be better understood to determine hydrological pathways. We use naturally-occurring, dissolved cations as tracers to identify the contribution of different water sources and interpret storm events. Water samples taken from springs (groundwater), surface water, and storm water on the Farm were analyzed for dissolved cations via ICP-OES for sodium (Na+), potassium (K+), calcium (Ca2+), and magnesium (Mg2+). A V-notch weir was used to quantify volumetric flow for a rain event during tropical storm Cindy. Ca2+ and Mg2+ concentrations (55.5-80.0 mg/L and 21.7-32.5 mg/L, respectively) and lower Na+ and K+ concentrations (9.6-14.8 mg/L and 1.7-18.3 mg/L, respectively) seem to predominantly characterize source groundwater. During Cindy, Ca2+, Mg2+, and Na+ decreased with increasing volumetric flow rate, likely indicating dilution of groundwater. However, K+ exhibited elevated concentrations that spike concurrently with initial discharge peaks and then progressively decrease over the duration of the storm event. We hypothesize that initial K+ increases represent significant overland flow followed by dilution with groundwater and/or continued runoff. If nutrient runoff behavior is similar to potassium, those nutrients should exhibit peak export with initial runoff

    Market Valuations in the New Economy: An Investigation of What Has Changed

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    We find mixed support for the hypothesis that a “New Economy” subperiod occurred in the late 1990s in which the relation between equity value and traditional financial variables differs from previous periods. We examine a regression model of equity value on financial variables over 25 years for a broad firm sample and for firm subsamples thought to be emblematic of the New Economy. We find the regression model\u27s explanatory power declined in the New Economy subperiod for all firm subsamples. However, for all subsamples, the regression model\u27s structure during the New Economy subperiod is not unusual compared to other subperiods

    Natural Selection For Environmentally Induced Phenotypes In Tadpoles

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137452/1/evo05119.pd

    Characterization of groundwater and surface water geochemistry in an agricultural setting at EKU Meadowbrook Farm, Madison County, Kentucky

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    Agricultural activities often contaminate watersheds with excess nutrients leading to poor water quality and eutrophication. Eastern Kentucky University (EKU) Meadowbrook Farm raises crops and livestock, which contribute dissolved nutrients to the neighboring Muddy Creek watershed. Consequently, the Farm is developing methods to sequester phosphorous and limit nutrient contamination. Before phosphorous sequestration methods can be tested, Farm surface water and groundwater geochemistry must be better understood to determine hydrological pathways for nutrients. We use naturally-occurring dissolved cations, pH, oxidation-reduction potential (ORP), specific conductivity (SC), dissolved oxygen (DO%), total hardness, and alkalinity as chemical tracers to parse the contribution of dissolved ions from different water sources, to recognize different water source chemistries, and to interpret storm events. To measure discharge from a proximal, intermittent stream that drains a representative and critical portion of the Farm, we used an instrumented, V-notch weir to examine storm-water flow during Tropical Storm Cindy (June 22-25, 2017). Water samples taken from springs (groundwater), surface water, and storm water on the Farm were analyzed for various dissolved constituents. Dissolved cations were measured via ICP-OES (ACT Labs) for sodium (Na+), potassium (K+), calcium (Ca2+), and magnesium (Mg2+). pH, ORP, SC, and DO% were determined with YSI and Vernier probes. Alkalinity and total hardness were measured via the bromocresol green - methyl red and the EDTA digital titration methods, respectively. Dissolved ammonium (NH4+), nitrate (NO3-), and phosphate (PO43-) concentrations were determined by colorimetry with a UV-VIS spectrophotometer via the sodium hypochlorite, cadmium reduction, and ascorbic acid methods, respectively. Both groundwater and surface water sources exhibit similar ranges of pH (neutral to basic), ORP (oxidizing), alkalinity, total hardness, DO%, and SC. Source waters generally have high Ca2+ and Mg2+, and low K+, Na+, PO43-, and NH4+ concentrations. This strongly suggests that background chemistries of source groundwater and surface water are controlled by local limestone bedrock dissolution. Groundwater is further characterized by relatively high NO3- concentrations and low temperatures; in contrast, surface waters exhibit higher temperatures and lower NO3- concentrations. During the Cindy event, concentration of Ca2+, Mg2+, and Na+ within baseline source waters decreased with increasing discharge through the weir (Fig. 1), along with SPC, pH, and alkalinity. This behavior represents dilution of Farm groundwater by storm precipitation and subsequent overland flow. However, K+ increased from baseline concentrations, spiking concurrently with increased discharge through the weir, and then progressively decreased in magnitude over the duration of the storm (Fig. 2). These data suggest that K+ was flushed from soil by rain waters. Nutrient concentrations increase with increased discharge indicating transport by surface runoff. For example, PO43- concentrations closely track and are proportional to discharge, which suggests PO43- transport from the surficial soil substrate via flushing by precipitation (Fig. 3). NO3- exhibited nearly identical transport behavior as K+; concentration spikes occur simultaneously with K+ and discharge. However, NO3- levels reached a higher baseline concentration than pre-storm levels. The Cindy event suggests infiltration and retention of NO3- within soil and groundwater during fair weather, initial flushing during the rain event, and then prolonged NO3- release from Farm soil and groundwater. Background concentration of NH4+ is generally 0.0 to 0.2 mg/L. Immediately prior to water flow over the weir during the Cindy event, concentrations were unusually high (~1.7 mg/L). During the first storm pulse, these high concentrations decreased significantly to \u3c0.4 mg/L. Later in the main storm event, NH4+ tracked discharge from the weir and afterward returned to typical background concentrations. This behavior suggests rapid release of NH4+ from soil followed by accumulation within the weir pool and then subsequent flushing during the precipitation event

    Battleground Texas: Gendered Media Framing of the 2014 Texas Gubernatorial Race

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    Feminist political theory is a sprawling theoretical field that intertwines sociological and philosophical perspectives and applies them to the study of campaigns, policy, voting, and the general structure of what Americans call politics. In Western democratic republics, the concept of participation has been hotly debated, specifically with regard to voting. Applying the critical lens of an intersectional feminist perspective introduces questions about the participation of different genders, races, classes, and cultural groups in political action, voting, and running for office. Before equal representation can be attained (if that is, indeed, desirable), it is important to understand how our politics are constructed. Feminism in the field of political communication is almost as old as the discipline itself. In this paper, the researchers explore a specific mixed-gender race in Texas, using the underlying assumptions of feminist political theory as a lens to examine how the race was rhetorically constructed in the media. By mixing methodologies and multiple analyses, both content-related and critical, these stories of mixed-gender campaigns may illuminate how gender is constructed in political races by the media and elucidate the potential constraints imposed on candidates seeking office

    Nutrient contamination from non-point sources: Dissolved nitrate and ammonium in surface and subsurface waters at EKU Meadowbrook Farm, Madison County, Kentucky

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    Agricultural activities often contaminate watersheds with excess nutrients leading to poor water quality and eutrophication. We assayed dissolved nutrient levels in surface and subsurface waters of Eastern Kentucky University’s Meadowbrook Farm in order to assess levels of dissolved nutrients leaving its farmland and draining into the Muddy Creek watershed. The Farm raises both crops and livestock so that nutrient sources include fertilizer and manure. We sampled springs, runoff, and subsurface pipe drainage as well as Muddy Creek on six days from May to August 2016 under a variety of weather conditions. Using established, standard colorimetric methods, we measured nitrate (NO3-; cadmium reduction method) and ammonium (NH4+; sodium hypochlorate method) via spectrophotometry with a precision and accuracy of ~0.1 mg/L. Nitrate was the dominant dissolved nitrogen species whereas ammonium was often absent in water samples. Nitrate levels were typically \u3c2 mg/L N- N- NO3 with the largest values between 7.0 and 14.3 mg/L. Springs and some runoff samples had higher nitrate values. Ammonium generally ranged between 0.0 and 0.5 mg/L N- NH4 with concentration spikes between 2.0 and 4.3 mg/L, but from no consistent source. Dissolved nitrogen concentration values responded to rainfall. Generally, nitrate concentrations increased more than ammonium concentrations during wetter periods. Spring samples maintained higher nitrogen concentrations regardless of different rainfall conditions. Lastly, nitrate contamination was significantly lower than composite national values from streams draining agricultural lands, whereas ammonium was about equal to the median national average. Median nitrate concentration was ~1.8 mg/L N- NO3 compared to the national value of ~2.8 mg/L, whereas the value for pristine streams is 0.24 mg/L N- NO3 (Dubrovsky et al., 2010). Median ammonium values from both data sets are ~0.1 mg/L N- NH4; the national value from pristine streams is ~0.025 mg/L N
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