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Registros recuperados: 16
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Advances in Data Processing for Open-path Fourier Transform Infrared Spectrometry of Greenhouse Gases. NWISRL
Shao, L.; Griffiths, P.R.; Leytem, A.B..
The automated quantification of three greenhouse gases, ammonia, methane and nitrous oxide, in the vicinity of a large dairy farm by open-path Fourier transform infrared (OP/FT-IR) spectrometry at intervals of 5 minutes is demonstrated. Spectral pretreatment, including the detection and correction of the effect of interrupting the infrared beam is by a moving object, and ways of correcting for the effect, and correction for the nonlinear detector response are applied to the measured interferograms. Two ways of obtaining quantitative data from OP/FT-IR data are described. The first, which is installed in commercial OP/FT-IR spectrometers, is based on classical least squares (CLS) regression and the second is based on partial least squares (PLS)...
Tipo: Article Palavras-chave: Air Emissions.
Ano: 2010 URL: http://eprints.nwisrl.ars.usda.gov/1422/1/1392.pdf
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Airborne Endotoxin from Indoor and Outdoor Environments: Effects of Sample Dilution on the Kinetic Limulus Amebocyte Lysate (LAL) Assay. NWISRL
Dungan, R.S..
Airborne endotoxin in occupational environments are a potential respiratory hazard to individuals. In this study, total and inhalable airborne endotoxin samples were collected via filtration from inside animal housing units and downwind from agricultural production sites and a wastewater treatment plant. Filter extracts were then diluted to examine the effect of interfering substances on the kinetic Limulus amebocyte lysate (LAL) assay. In most cases, the overall endotoxin concentration was shown to decrease with increasing dilution up to 1,000-fold, suggesting the presence of enhancing substances in the filter extracts. This dilution dependent effect was most prominent in the inhalable endotoxin samples, while total endotoxin samples displayed little...
Tipo: Article Palavras-chave: Air Emissions; Endotoxins.
Ano: 2011 URL: http://eprints.nwisrl.ars.usda.gov/1410/1/1380.pdf
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Ambient Endotoxin Concentrations and Assessment of Offsite Transport at Open-Lot and Open-Freestall Dairies NWISRL
Dungan, R.S.; Leytem, A.B..
Endotoxins are derived from gram-negative bacteria and are a potent inducer of inflammatory reactions in the respiratory tract when inhaled. To assess daily fluctuations of airborne endotoxin and their potential for transport from dairies, endotoxin concentrations were monitored over an 8-h period at upwind (background) and downwind (5 m from edge of dairy) locations on three separate days at two dairies. The dairies consisted of an open-lot or an open-freestall production system, both of which were stocked with 10,000 milking cows. Upwind concentrations were stable throughout the sampling period, averaging between 1.2 and 36.8 endotoxin units (EU) m-3, whereas downwind concentration averages ranged from 179 to 989 EU-3. Downwind endotoxin concentrations...
Tipo: Article Palavras-chave: Air Emissions; Endotoxins; Manure Management.
Ano: 2011 URL: http://eprints.nwisrl.ars.usda.gov/1411/1/1381.pdf
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Antibiotics in agroecosystems: Introduction to the special section NWISRL
Franklin, A.M.; Aga, D.S.; Cytryn, Eddie; Durso, L.M.; Mclain, J.E.; Pruden, Amy; Roberts, M.C.; Rothrock, Jr, M.J.; Snow, D.D.; Watson, J.E.; Dungan, R.S..
The presence of antibiotic drug residues, antibiotic resistant bacteria, and antibiotic resistance genes in agroecosystems has become a significant area of research in recent years, and is a growing public health concern. While antibiotics are utilized for human medicine and agricultural practices, the majority of antibiotic use occurs in food animals where these drugs have historically been used for growth promotion, in addition to prevention and treatment of disease. The widespread use of antibiotics combined with the application of human and animal wastes to agricultural fields introduces antibiotic-related contamination into the environment. While overt toxicity in organisms directly exposed to antibiotic in agroecosystems is generally not an issue due...
Tipo: Article Palavras-chave: Air Emissions; Animal; Runoff; Manure.
Ano: 2016 URL: http://eprints.nwisrl.ars.usda.gov/1614/1/1571.pdf
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Assessment of Bioaerosols at a Concentrated Dairy Operation. NWISRL
Dungan, R.S.; Leytem, A.B.; Verwey, S.; Bjorneberg, D.L..
Increased bioaerosol loadings in downwind plumes from concentrated animal feeding operations (CAFOs) may increase the risk for allergy and infection in humans. In this study we monitored airborne concentrations of culturable bacteria and fungi at upwind (background) and downwind sites at a 10,000 milking cow dairy over the course of a year. The average bacterial concentrations at the upwind site were 8,400 colony forming units (CFU)/cubic meter and increased to 990,000 CFU/cubic meter at the downwind edge of the cattle pens, decreasing to 63,000 CFU/cubic meter 200 m farther downwind. At the same sites, the average fungal concentrations were 515, 945, and 1010 CFU/cubic meter, respectively. Significant correlations between the ambient weather data and...
Tipo: Article Palavras-chave: Manure Management; Air Emissions; Bioaerosols.
Ano: 2010 URL: http://eprints.nwisrl.ars.usda.gov/1403/1/1373.pdf
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Comparison of atmospheric stability methods for calculating ammonia and methane emission rates with WindTrax NWISRL
Koehn, A.C.; Leytem, A.B.; Bjorneberg, D.L..
Inverse dispersion models are useful tools for estimating emissions from animal feeding operations, waste storage ponds, and manure application fields. Atmospheric stability is an important input parameter to such models. The objective of this study was to compare emission rates calculated with a backward Lagrangian stochastic (bLS) inversedispersion model (WindTrax) using three different methods for calculating atmospheric stability: sonic anemometer, gradient Richardson number, and Pasquill-Gifford (P-G) stability class. Ammonia and methane emission data from a compost yard at a 10,000-cow dairy were used for the comparisons. Overall, average emission rates were not significantly different among the stability methods. Emission rates correlated well...
Tipo: Article Palavras-chave: Air Emissions.
Ano: 2013 URL: http://eprints.nwisrl.ars.usda.gov/1490/1/1454.pdf
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Concentrations of Airborne Endotoxin and Microorganisms at a 10,000 Cow Open-Freestall Dairy NWISRL
Dungan, R.S.; Leytem, A.B.; Bjorneberg, D.L..
Confined animal production systems produce elevated bioaerosol concentrations, which are a potential respiratory health risk to individuals on site and downwind. In this study, airborne endotoxin and microorganisms were collected during the spring, summer, and fall at a large open-freestall dairy in southern Idaho. Compared to the background ambient atmosphere, both endotoxin and culturable heterotrophic bacteria concentrations were up to several-hundred fold greater 50 m downwind from the facility, then decreased to near background concentrations at 200 m. However, downwind fungi concentrations were not elevated above background concentrations. At 50 m downwind, the average inhalable endotoxin concentration ranged from 4.6 to 4243 endotoxin units/cubic...
Tipo: Article Palavras-chave: Air Emissions; Manure.
Ano: 2011 URL: http://eprints.nwisrl.ars.usda.gov/1437/1/1404.pdf
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Detection of purple sulfur bacteria in purple and non-purple dairy wastewaters NWISRL
Dungan, R.S.; Leytem, A.B..
Purple sulfur bacteria (PSB) in livestock wastewaters use reduced sulfur compounds and simple volatile organics as growth factors. As a result, the presence of PSB in manure storage ponds or lagoons is often associated with reduced odors. In this study, our objectives were to use molecular- and culture-based techniques to evaluate the occurrence of PSB in eight dairy wastewater ponds and identify physiochemical properties that might cause blooms to occur. Community DNA was extracted from composited wastewater samples, then the PufM gene and a conservative sequence for Chromatiaceae were amplified. Analysis of the 16S rRNA genes from denaturing gradient gel electrophoresis (DGGE) bands indicated that all of the dairy wastewater ponds contained sequences...
Tipo: Article Palavras-chave: Air Emissions.
Ano: 2015 URL: http://eprints.nwisrl.ars.usda.gov/1604/1/1562.pdf
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Effect of dietary crude protein and forage contents on enteric methane emissions and nitrogen excretion from dairy cows simultaneously NWISRL
Niu, M; Appuhamy, J.A.D.R.N; Leytem, A.B.; Dungan, R.S.; Kebreab, Ermias.
The study aimed to examine, simultaneously, the effects of changing dietary forage and crude protein (CP) contents on methane (CH4) emissions and nitrogen (N) excretion from lactating dairy cows. Twelve post-peak lactating Holstein cows were randomly assigned to 4 treatments from a 2×2 factorial arrangement of two dietary forage levels [37.4% (LF) vs. 53.3% (HF) of DM] and two dietary CP levels [15.2% (LP) vs. 18.5% (HP) of DM] in a 4×4 Latin square design with four 18 d periods. Alfalfa hay was the sole source of dietary forage. Cows were fed and milked twice daily. During the first 14 d, cows were housed in a free-stall barn, where enteric CH4 emissions were measured using the GreenFeed system from d 8 to 14 in each period. Cows were then moved to...
Tipo: Article Palavras-chave: Air Emissions; Animal Production; Feed preference; Animal.
Ano: 2016 URL: http://eprints.nwisrl.ars.usda.gov/1618/1/1575.pdf
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Greenhouse gas and ammonia emissions from an open-freestall dairy in Southern Idaho NWISRL
Leytem, A.B.; Dungan, R.S.; Bjorneberg, D.L.; Koehn, A.C..
Concentrated dairy operations emit trace gases such as ammonia (NH3), methane (CH4), and nitrous oxide (N2O) to the atmosphere. The implementation of air quality regulations in livestock-producing states increases the need for accurate on-farm determination of emission rates. The objective of this study was to determine the emission rates of NH3, CH4, and N2O from the open-freestall and wastewater pond source areas on a commercial dairy located in southern Idaho. Gas concentrations and wind statistics were measured each month and used with an inverse dispersion model to calculate emission rates. Average emissions per cow per day from the open-freestall source area were 0.10 kg NH3 and 0.47 kg CH4. Average emissions from the wastewater ponds (g m-2 d-1)...
Tipo: Article Palavras-chave: Air Emissions; Animal Production; Manure Management.
Ano: 2013 URL: http://eprints.nwisrl.ars.usda.gov/1501/1/1464.pdf
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High yield corn production can result in high nitrogen use efficiency NWISRL
Wortmann, C.C.; Shapiro, C.A.; Dobermann, Achim; Ferguson, Richard; Hergert, G; Walters, Daniel; Tarkalson, D.D..
Alarm is expressed about the environmental impact of the increasing amount of reactive N in the atmosphere and in terrestrial and marine ecosystems around the globe. Much of this increase is attributed to production and use of N fertilizer. Use of fertilizer N is essential to meet growing global demand for agricultural commodities. Management is key to increasing productivity while also increasing N use efficiency and reducing N losses. A team of University of Nebraska-Lincoln scientists, with partial funding from the Nebraska State Legislature, addressed this challenge. They conducted 32 irrigated trials across diverse production conditions of Nebraska from 2002 to 2004 to evaluate corn response to rates of split-applied N. The results were reported in...
Tipo: Article Palavras-chave: Air Emissions; Chemistry; Fertilizer; Nitrogen; Soil.
Ano: 2011 URL: http://eprints.nwisrl.ars.usda.gov/1579/1/1535.pdf
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Increasing the quantitative credibility of open-path FT-IR spectroscopic data with focus on several properties of the background spectrum NWISRL
Shao, L.; Wang, Wanping; Griffiths, P.R.; Leytem, A.B..
The choice of the type of background spectrum affects the credibility of open-path Fourier transform infrared (OP/FT-IR) spectroscopic data, and consequently the quality of data analysis. We systematically investigated several properties of the background spectrum. The results show that a short-path background measured with the lowest amplifier gain could significantly reduce noise in the calculated absorbance spectrum, by at least 30% in our case. We demonstrated that by using a short-path background, data analysis is more resistant to interferences, such as wavenumber shift or resolution alteration that occurs as a consequence of hardware aging or misalignment. We also discussed a systematic error introduced into quantitative analyses by the...
Tipo: Article Palavras-chave: Air Emissions.
Ano: 2013 URL: http://eprints.nwisrl.ars.usda.gov/1507/1/1470.pdf
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Livestock GRACEnet: A workgroup dedicated to evaluating and mitigating emissions from livestock production NWISRL
Leytem, A.B.; Dungan, R.S..
livestock operations can potentially affect air quality at local, regional, and even global scales. These pollutants, many of which are generated through various anthropogenic activities, are being increasingly scrutinized by regulatory authorities. Regulation of emissions from livestock production systems will ultimately increase on farm costs, which will then be passed onto consumers. Therefore, it is essential that scientifically based emission factors are developed for on-farm emissions of air quality constituents to improve inventories and assign appropriate reduction targets. To generate a larger database of on-farm emissions, the USDA–ARS created the workgroup Livestock GRACEnet (Greenhouse gas Reduction through Agricultural Carbon Enhancement...
Tipo: Article Palavras-chave: Air Emissions; Application guidelines; Chemistry.
Ano: 2014 URL: http://eprints.nwisrl.ars.usda.gov/1542/1/1499.pdf
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Nutritional and environmental effects on ammonia emissions from dairy cattle housing: A meta-analysis NWISRL
Bougouin, Adeline; Leytem, A.B.; Dijkstra, Jan; Dungan, R.S.; Kebreab, Ermias.
Nitrogen (N) excreted in urine by dairy cows can be potentially transformed to ammonia (NH3) and emitted to the atmosphere. Dairy production contributes to NH3 emission, which can create human respiratory problems and odor issues, reduces manure quality, and is an indirect source of nitrous oxide (N2O). The objective of this study was to (i) investigate environmental factors and measurement method that influence NH3 from dairy housing, and (ii) identify key explanatory variables in the prediction of NH3 emissions from dairy barns using a meta-analytical approach. Data from 25 studies were used for the preliminary analysis and data from 10 studies reporting 87 treatment means were used for the meta-analysis. Season, flooring type, manure handling and...
Tipo: Article Palavras-chave: Air Emissions; Animal Production; Animal health; Manure.
Ano: 2016 URL: http://eprints.nwisrl.ars.usda.gov/1624/1/1581.pdf
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Recovery of culturable of Escherichia coli O157:H7 during operation of a liquid-based bioaerosol sampler NWISRL
Dungan, R.S.; Leytem, A.B..
Collection fluids used in liquid-based bioaerosol samplers can influence the viability of microorganisms. In this study we determined the recovery efficiency of vegetative E. coli O157:H7 cells that were spiked into low viscosity evaporating collection fluids during operation of a BioSampler™ for up to 90 min at room temperature. The collection fluids tested were distilled (DI) water, phosphate-buffered saline (PBS) and osmoprotectants consisting of peptone and/or antifoam or betaine at 0.1% (w/w) in DI water. Using DI water, there was a rapid decline in the recovery of culturable E. coli, with only 11, 3, and 0% being recovered after 30, 60, and 90 min, respectively. Recoveries were substantially greater with use of PBS (53, 25, and 16%, respectively) but...
Tipo: Article Palavras-chave: Air Emissions; Water quality.
Ano: 2016 URL: http://eprints.nwisrl.ars.usda.gov/1613/1/1570.pdf
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Using Multiple Calibration Sets to Improve the Quantitative Accuracy of Partial Least Squares (PLS) Regression on Open-Path Fourier Transform Infrared (OP/FT-IR) Spectra of Ammonia over Wide Concentration Ranges NWISRL
Shao, Limin; Bianxia, Liu; Griffiths R, Peter; Leytem, A.B..
A technique of using multiple calibration sets in partial least squares regression (PLS) was proposed to improve the quantitative determination of ammonia from open-path Fourier transform infrared spectra. The spectra were measured near animal farms, and the path-integrated concentration of ammonia fluctuated from nearly zero to a high of about 1000 ppm-m. The PLS regression using a single calibration set over such a large concentration range had decreased quantitative accuracy due to the nonlinear relationship between concentration and absorbance. In the PLS regression with multiple calibration sets, each calibration set accounted for a smaller concentration range, which significantly decreased the serious nonlinearity problem in PLS regression with a...
Tipo: Article Palavras-chave: Air Emissions; Manure.
Ano: 2011 URL: http://eprints.nwisrl.ars.usda.gov/1428/1/1398.pdf
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