Manure management strategies are interconnected with complexity across U.S. dairy farms.

Among one of the key challenges in dairy production is the management of manure in a way that is beneficial for agricultural production, with minimal environmental and public health impacts. Manure management systems (MMS)-the entire system of handling, storage, and application of manure-are diverse in countries with developed dairy industries such as the United States, enabled by a number of different technologies. The ways in which dairy farmers manage manure is driven by varying tradeoffs, including economic, social, and environmental; however, existing research has not examined the relationships between components of MMS. Here we use data from the National Animal Health Monitoring System's Dairy 2014 study to explore the ways in which manure handling, storage, and application are related, using a series of logistic regression models and network associations. We found significant associations between how manure is handled, stored, and applied, especially driven by the consistency of manure. For solid manure, we found highly heterogeneous systems, where farmers may have a suite of alternative manure management strategies available to them, and substitution is viable. Conversely, farms using liquid manure systems have very few substitutes in their MMS, suggesting greater investment in certain infrastructures, which are not easily changed. Such findings have important implications for shifting farmers towards management practices with minimal environmental and public health impacts, demonstrating that not all farm systems are easily changed. We highlight these results in light of current policies, which may not fully capture the relationships across the MMS, and suggest that greater financing may be necessary to shift MMS on some farms. Furthermore, we suggest that different MMS have varying tradeoffs across environmental, social, and economic aspects, which demonstrates that MMS are highly individualized to a given farm's goals and priorities.

Analyzing the impacts of three types of biochar on soil carbon fractions and physiochemical properties in a corn-soybean rotation.

Biochar is a solid material obtained when biomass is thermochemically converted in an oxygen-limited environment. In most previous studies, the impacts of biochar on soil properties and organic carbon (C) were investigated under controlled conditions, mainly laboratory incubation or greenhouse studies. This 2-year field study was conducted to evaluate the influence of biochar on selected soil physical and chemical properties and carbon and nitrogen fractions for two selected soil types (clay loam and a sandy loam soil) under a corn (Zea mays L.)-soybean (Glycine max L.) rotation. The three plant based biochar materials used for this study were corn stover (CS), ponderosa pine (Pinus ponderosa Lawson and C. Lawson) wood residue (PW), and switchgrass (Panicum virgatum L.) (SG). Data showed that CS and SG significantly increased the pH of acidic soil at the eroded landscape position but produced no significant change in soil pH at the depositional landscape position. The effects of biochar treatments on cold water extractable C (WSC) and nitrogen (WSN) fractions for the 0-7.5 cm depth were depended on biochar and soil type. Results suggested that alkaline biochars applied at 10 Mg ha-1 can increase the pH and WSC fraction of acidic sandy loam soil, but the 10 Mg ha-1 rate might be low to substantially improve physical properties and hot water extractable C and N fractions of soil. Application of higher rates of biochar and long-term monitoring is needed to quantify the benefits of biochar under field conditions on soils in different environmental conditions.

Comparison of the Physical and Chemical Properties of Laboratory and Field-Aged Biochars.

The long-term impact of biochar on soil properties and agronomic outcomes is influenced by changes in the physical and chemical properties of biochars that occur with time (aging) in soil environments. Fresh biochars, however, are often used in studies because aged biochars are generally unavailable. Therefore, a need exists to develop a method for rapid aging of biochars in the laboratory. The objectives of this study were to compare the physicochemical properties of fresh, laboratory-aged (LA), and field-aged (FA) (≥3 yr) biochars and to assess the appropriateness of a laboratory aging procedure that combines acidification, oxidation, and incubations as a mimic to field aging in neutral or acidic soil environments. Twenty-two biochars produced by fast and slow pyrolysis, and gasification techniques from five different biomass feedstocks (hardwood, corn stover, soybean stover, macadamia nut shells, and switchgrass) were studied. In general, both laboratory and field aging caused similar increases in ash-free volatile matter (% w/w), cation and anion exchange capacities, specific surface area, and modifications in oxygen-containing surface functional groups of the biochars. However, ash content increased for FA (18-195%) and decreased for LA (22-74%) biochars, and pH decreased to a greater extent for LA (2.8-6.7 units) than for FA (1.6-3.8 units) biochars. The results demonstrate that the proposed laboratory aging procedure is effective for predicting the direction of changes in biochar properties on field aging. However, in the future we recommend using a less aggressive acid treatment.

Modeling the impacts of temperature and precipitation changes on soil CO2 fluxes from a Switchgrass stand recently converted from cropland.

Switchgrass (Panicum virgatum L.) is a perennial C4 grass native to North America and successfully adapted to diverse environmental conditions. It offers the potential to reduce soil surface carbon dioxide (CO2) fluxes and mitigate climate change. However, information on how these CO2 fluxes respond to changing climate is still lacking. In this study, CO2 fluxes were monitored continuously from 2011 through 2014 using high frequency measurements from Switchgrass land seeded in 2008 on an experimental site that has been previously used for soybean (Glycine max L.) in South Dakota, USA. DAYCENT, a process-based model, was used to simulate CO2 fluxes. An improved methodology CPTE [Combining Parameter estimation (PEST) with "Trial and Error" method] was used to calibrate DAYCENT. The calibrated DAYCENT model was used for simulating future CO2 emissions based on different climate change scenarios. This study showed that: (i) the measured soil CO2 fluxes from Switchgrass land were higher for 2012 which was a drought year, and these fluxes when simulated using DAYCENT for long-term (2015-2070) provided a pattern of polynomial curve; (ii) the simulated CO2 fluxes provided different patterns with temperature and precipitation changes in a long-term, (iii) the future CO2 fluxes from Switchgrass land under different changing climate scenarios were not significantly different, therefore, it can be concluded that Switchgrass grown for longer durations could reduce changes in CO2 fluxes from soil as a result of temperature and precipitation changes to some extent.

Rapid cost-effective analysis of microbial activity in soils using modified fluorescein diacetate method.

Fluorescein diacetate (FDA) is commonly used to determine the hydrolyzing activity of microbial organisms in the soil. However, the costs of chemical reagents and time required to perform routine analysis of large number of samples by soil testing laboratories are limiting. Moreover, existing methods generate significant volumes of hazardous waste. In this context, this study was designed to determine the minimum amount of terminating chemical reagent needed to evaluate microbial hydrolyzing activity. The results showed that 0.2 mL of chloroform was enough to effectively stop the hydrolyzing activity in soil. This proposed terminating chemical reagent (0.2 mL chloroform) was also evaluated by comparing with the 10 mL of chloroform and 5 mL of methanol used in the Adam and Duncan method.

Denitrification kinetics in biomass- and biochar-amended soils of different landscape positions.

Knowledge of how biochar impacts soil denitrification kinetics as well as the mechanisms of interactions is essential in order to better predict the nitrous oxide (N2O) mitigation capacity of biochar additions. This study had multiple experiments in which the effect of three biochar materials produced from corn stover (Zea mays L.), ponderosa pine wood residue (Pinus ponderosa Douglas ex Lawson and C. Lawson), switchgrass (Panicum virgatum L.), and their corresponding biomass materials (corn stover, ponderosa pine wood residue, and switchgrass) on cumulative N2O emissions and total denitrification in soils from two different landscape positions (crest and footslope) were studied under varying water-filled pore space (40, 70, and 90% WFPS). Cumulative N2O emissions were reduced by 30 to 70% in both crest and footslope soils. The effect of biochars and biomass treatments on cumulative N2O emissions and total denitrification were only observed at ≥40% WFPS. The denitrification enzyme activity (DEA) kinetic parameters, K s (half-saturation constant), and V max (maximum DEA rate) were both significantly reduced by biochar treatments, with reductions of 70-80% in footslope soil and 80-90 % in the crest soil. The activation energy (E a) and enthalpy of activation of DEA (ΔH) were both increased with biochar application. The trends in DEA rate constants (K s and V max) were correlated by the trends of thermodynamic parameters (activation energy E a and enthalpy of activation ΔH) for denitrifying enzyme activity (DEA). The rate constant V max/K s evaluated the capacity of biochars to mitigate the denitrification process. Denitrifying enzyme kinetic parameters can be useful in evaluating the ability of biochars to mitigate N2O gas losses from soil.

Molecular characterization of biochars and their influence on microbiological properties of soil.

The tentative connection between the biochar surface chemical properties and their influence on microbially mediated mineralization of C, N, and S with the help of enzymes is not well established. This study was designed to investigate the effect of different biomass conversion processes (microwave pyrolysis, carbon optimized gasification, and fast pyrolysis using electricity) on the composition and surface chemistry of biochar materials produced from corn stover (Zea mays L.), switchgrass (Panicum virgatum L.), and Ponderosa pine wood residue (Pinus ponderosa Lawson and C. Lawson) and determine the effect of biochars on mineralization of C, N, and S and associated soil enzymatic activities including esterase (fluorescein diacetate hydrolase, FDA), dehydrogenase (DHA), ß-glucosidase (GLU), protease (PROT), and aryl sulfatase (ARSUL) in two different soils collected from footslope (Brookings) and crest (Maddock) positions of a landscape. Chemical properties of biochar materials produced from different batches of gasification process were fairly consistent. Biochar materials were found to be highly hydrophobic (low H/C values) with high aromaticity, irrespective of biomass feedstock and pyrolytic process. The short term incubation study showed that biochar had negative effects on microbial activity (FDA and DHA) and some enzymes including ß-glucosidase and protease.

Spontaneous coronary artery dissection: aggressive vs. conservative therapy.

BACKGROUND: Spontaneous coronary artery dissection (SCAD) is a rare condition that commonly presents as an acute coronary event in the younger population, especially in females of childbearing age. Generally, there is no consensus on the etiology, prognosis, and treatment of SCAD. METHODS: The Medline database was searched for "spontaneous coronary artery dissection" between 1931 and 2008. A total of 440 cases of SCAD were identified. Demographic data were analyzed with either the Student's t-test or the chi-square test for categorical and nominal variables, respectively. Kaplan-Meier outcome analysis was used to assess the outcome of a given treatment for all patients after 1990. RESULTS: SCAD was found more commonly in females with 308 (70%) cases. Pregnancy was associated with SCAD in 80 (26.1%) cases. Among pregnant patients, 67 (83.8%) developed SCAD in the postpartum period and 13 (16.2%) patients in the prepartum period. Analysis of treatment modalities showed that 21.2% of the patients who were conservatively managed after the initial diagnosis eventually required surgical or catheter-based intervention compared to 2.5% of patients who were initially treated with an aggressive strategy. Kaplan-Meier analysis showed that patients with an isolated single lesion in left or right coronary artery had a statistically significant better outcome when treated with an early aggressive strategy, including coronary artery bypass grafting (CABG) or stent placement as compared to a conservative strategy (p = 0.023, p = 0.006, respectively). CONCLUSION: Early intervention with either CABG or percutaneous coronary intervention following the diagnosis of SCAD leads to a better outcome and less need for further intervention.

Essential role of the 90-kilodalton heat shock protein in mediating nongenomic estrogen signaling in coronary artery smooth muscle.

Under normal physiological conditions, estrogen is a coronary vasodilator, and this response involves production of NO from endothelial cells. In addition, estrogen also stimulates NO production in coronary artery smooth muscle (CASM); however, the molecular basis for this nongenomic effect of estrogen is unclear. The purpose of this study was to investigate a potential role for the 90-kDa heat shock protein (Hsp90) in estrogen-stimulated neuronal nitric-oxide synthase (nNOS) activity in coronary artery smooth muscle. 17Beta-estradiol produced a concentration-dependent relaxation of endothelium-denuded porcine coronary arteries in vitro, and this response was attenuated by inhibiting Hsp90 function with 1 microM geldanamycin (GA) or 100 microg/ml radicicol (RAD). These inhibitors also prevented estrogen-stimulated NO production in human CASM cells and reversed the stimulatory effect of estrogen on calcium-activated potassium (BK(Ca)) channels. These functional studies indicated a role for Hsp90 in coupling estrogen receptor activation to NOS stimulation in CASM. Furthermore, coimmunoprecipitation studies demonstrated that estrogen stimulates bimolecular interaction of immunoprecipitated nNOS with Hsp90 and that either GA or RAD could inhibit this association. Blocking estrogen receptors with ICI182780 (fulvestrant) also prevented this association. These findings indicate an essential role for Hsp90 in nongenomic estrogen signaling in CASM and further suggest that Hsp90 might represent a prospective therapeutic target to enhance estrogen-stimulated cardiovascular protection.

Nongenomic, endothelium-independent effects of estrogen on human coronary smooth muscle are mediated by type I (neuronal) NOS and PI3-kinase-Akt signaling.

Sex steroids exert profound and controversial effects on cardiovascular function. For example, estrogens have been reported to either ameliorate or exacerbate coronary heart disease. Although estrogen dilates coronary arteries from a variety of species, the molecular basis for this acute, nongenomic effect is unclear. Moreover, we know very little of how estrogen affects human coronary artery smooth muscle cells (HCASMC). The purpose of this study was to elucidate nongenomic estrogen signal transduction in HCASMC. We have used tissue (arterial tension studies), cellular (single-channel patch clamp, fluorescence), and molecular (protein expression) techniques to now identify novel targets of estrogen action in HCASMC: type I (neuronal) nitric oxide synthase (nNOS) and phosphatidylinositol 3-kinase (PI3-kinase)Akt. 17beta-Estradiol (E(2)) increased NO-stimulated fluorescence in HCASMC, and cell-attached patch-clamp experiments revealed that stimulation of nNOS leads to increased activity of calcium-activated potassium (BK(Ca)) channels in these cells. Furthermore, overexpression of nNOS protein in HCASMC greatly enhanced BK(Ca) channel activity. Immunoblot studies demonstrated that E(2) enhances Akt phosphorylation in HCASMC and that wortmannin, an inhibitor of PI3-kinase, attenuated E(2)-stimulated channel activity, NO production, Akt phosphorylation, and estrogen-stimulated coronary relaxation. These studies implicate the PI3-kinase/Akt signaling axis as an estrogen transduction component in vascular smooth muscle cells. We conclude, therefore, that estrogen opens BK(Ca) channels in HCASMC by stimulating nNOS via a transduction sequence involving PI3-kinase and Akt. These findings now provide a molecular mechanism that can explain the clinical observation that estrogen enhances coronary blood flow in patients with diseased or damaged coronary arteries.