150 research outputs found

    Evaluation of Irrigated and Non-Irrigated Corn Production in Brookings County

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    The evaluation of irrigated corn production requires crop water production functions which are time and location specific. This analysis evaluated irrigated and non-irrigated corn production from 1984 to 1993 in Brookings County. The CERES-Maize crop simulation model generated agronomic data which was representative of Brookings County. Crop budgets were created to establish production costs associated with the study area. Net returns for each of the production methods were compared

    Economic and Environmental Contributions of Wetlands in Agricultural Landscapes

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    The purpose of this project was to determine key environmental and economic relationships between agricultural practices and wetlands in the Prairie Pothole Region (PPR) of eastern South Dakota. Water quality and water quantity variables were the key environmental parameters examined. Economic cost and returns by farm management system and wetland proximity were the key economic parameters. The three farm management systems examined were conventional (CON) transitional no-till (TNT), and organic (ORG). The TNT and CON management systems used synthetic fertilizers and chemical pesticides. The ORG system used no synthetic fertilizers and generally no chemical pesticides. The ORG system had greater emphasis on alfalfa and lower emphasis on corn and soybean production. Water budgets were determined for upland and wetland sites. At the wetland site, run-on was the major input to the water budget (60%). Overflow accounted for 3 6% of the wetland output and surface storage /seepage accounted for 40%. Evapotranspiration at the wetland site was much lower than at the upland site. Nitrate concentrations were consistently higher in the semi-permanent wetland areas than the seasonal wetland areas. The data show a steady decrease in phosphate concentration as we move upland in the landscape. Higher concentrations in wetland than upland groundwater may indicate that some soluble P is moving through the system and/or the sorption capacity of wetland soils is exceeded. Economic returns and costs of the three farming systems were estimated for 1992 - 1994 at the whole-farm and crop field level. The relative ranking of net returns by management systems were: TNT \u3e CON \u3e ORG, unless organic premiums are a major source of gross income. Production costs per acre by management system from lowest to highest were ORG \u3c TNT \u3c CON. The organic (ORG) system had lower reported average yields and considerably lower production costs per acre than the other management systems. The TNT system had the least diversity of crop rotations, intermediate-level production costs, and similar yields or higher yields than reported in the CON system. The added costs of more tillage and machinery operations in the CON system exceeded any reduction in chemical costs compared to the TNT system. Biomass production and most corn/soybean yields were lowest adjacent to wetland sites and increased to peak production at 150 to 300 feet out. Several years of crop budget estimates for ORG, CON, and TNT fields adjacent to monitored wetland sites indicated substandard net returns in most years

    Evaluation of Irrigated and Non-Irrigated Corn Production in Brookings County; Hog Comments

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    Correction to: An isogenic neurovascular unit model comprised of human induced pluripotent stem cell-derived brain microvascular endothelial cells, pericytes, astrocytes, and neurons

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    Abstract Following publication of the original article [1], the author has reported that in Figure 1 (b and c) the y-axis TEER (© x cm2) should be replaced with TEER (Ω x cm2). Erratum for An isogenic neurovascular unit model comprised of human induced pluripotent stem cell-derived brain microvascular endothelial cells, pericytes, astrocytes, and neurons. [Fluids Barriers CNS. 2019

    Order within disorder: the atomic structure of ion-beam sputtered amorphous tantala (a-Ta2O5)

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    Amorphous tantala (a-Ta2O5) is a technologically important material often used in high-performance coatings. Understanding this material at the atomic level provides a way to further improve performance. This work details extended X-ray absorption fine structure measurements of a-Ta2O5 coatings, where high-quality experimental data and theoretical fits have allowed a detailed interpretation of the nearest-neighbor distributions. It was found that the tantalum atom is surrounded by four shells of atoms in sequence; oxygen, tantalum, oxygen, and tantalum. A discussion is also included on how these models can be interpreted within the context of published crystalline Ta 2O5 and other a-T2O5 studies

    Six-minute walk distance after coronary artery bypass grafting compared with medical therapy in ischaemic cardiomyopathy

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    Background: In patients with ischaemic left ventricular dysfunction, coronary artery bypass surgery (CABG) may decrease mortality, but it is not known whether CABG improves functional capacity. Objective: To determine whether CABG compared with medical therapy alone (MED) increases 6 min walk distance in patients with ischaemic left ventricular dysfunction and coronary artery disease amenable to revascularisation. Methods: The Surgical Treatment in Ischemic Heart disease trial randomised 1212 patients with ischaemic left ventricular dysfunction to CABG or MED. A 6 min walk distance test was performed both at baseline and at least one follow-up assessment at 4, 12, 24 and/or 36 months in 409 patients randomised to CABG and 466 to MED. Change in 6 min walk distance between baseline and follow-up were compared by treatment allocation. Results: 6 min walk distance at baseline for CABG was mean 340±117 m and for MED 339±118 m. Change in walk distance from baseline was similar for CABG and MED groups at 4 months (mean +38 vs +28 m), 12 months (+47 vs +36 m), 24 months (+31 vs +34 m) and 36 months (−7 vs +7 m), P>0.10 for all. Change in walk distance between CABG and MED groups over all assessments was also similar after adjusting for covariates and imputation for missing values (+8 m, 95% CI −7 to 23 m, P=0.29). Results were consistent for subgroups defined by angina, New York Heart Association class ≥3, left ventricular ejection fraction, baseline walk distance and geographic region. Conclusion: In patients with ischaemic left ventricular dysfunction CABG compared with MED alone is known to reduce mortality but is unlikely to result in a clinically significant improvement in functional capacity

    Order within disorder: The atomic structure of ion-beam sputtered amorphous tantala (a-Ta_2O_5)

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    Amorphous tantala (a-Ta_2O_5) is a technologically important material often used in high-performance coatings. Understanding this material at the atomic level provides a way to further improve performance. This work details extended X-ray absorption fine structure measurements of a-Ta_2O_5 coatings, where high-quality experimental data and theoretical fits have allowed a detailed interpretation of the nearest-neighbor distributions. It was found that the tantalum atom is surrounded by four shells of atoms in sequence; oxygen, tantalum, oxygen, and tantalum. A discussion is also included on how these models can be interpreted within the context of published crystalline Ta 2O5 and other a-T_2O_5 studies

    The global oscillation network group site survey. II. Results

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    The Global Oscillation Network Group (GONG) Project will place a network of instruments around the world to observe solar oscillations as continuously as possible for three years. The Project has now chosen the six network sites based on analysis of survey data from fifteen sites around the world. The chosen sites are: Big Bear Solar Observatory, California; Mauna Loa Solar Observatory, Hawaii; Learmonth Solar Observatory, Australia; Udaipur Solar Observatory, India; Observatorio del Teide, Tenerife; and Cerro Tololo Interamerican Observatory, Chile. Total solar intensity at each site yields information on local cloud cover, extinction coefficient, and transparency fluctuations. In addition, the performance of 192 reasonable components analysis. An accompanying paper describes the analysis methods in detail; here we present the results of both the network and individual site analyses. The selected network has a duty cycle of 93.3%, in good agreement with numerical simulations. The power spectrum of the network observing window shows a first diurnal sidelobe height of 3 × 10⁻⁴ with respect to the central component, an improvement of a factor of 1300 over a single site. The background level of the network spectrum is lower by a factor of 50 compared to a single-site spectrum

    Crystal Structures of Cif from Bacterial Pathogens Photorhabdus luminescens and Burkholderia pseudomallei

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    A pre-requisite for bacterial pathogenesis is the successful interaction of a pathogen with a host. One mechanism used by a broad range of Gram negative bacterial pathogens is to deliver effector proteins directly into host cells through a dedicated type III secretion system where they modulate host cell function. The cycle inhibiting factor (Cif) family of effector proteins, identified in a growing number of pathogens that harbour functional type III secretion systems and have a wide host range, arrest the eukaryotic cell cycle. Here, the crystal structures of Cifs from the insect pathogen/nematode symbiont Photorhabdus luminescens (a γ-proteobacterium) and human pathogen Burkholderia pseudomallei (a β-proteobacterium) are presented. Both of these proteins adopt an overall fold similar to the papain sub-family of cysteine proteases, as originally identified in the structure of a truncated form of Cif from Enteropathogenic E. coli (EPEC), despite sharing only limited sequence identity. The structure of an N-terminal region, referred to here as the ‘tail-domain’ (absent in the EPEC Cif structure), suggests a surface likely to be involved in host-cell substrate recognition. The conformation of the Cys-His-Gln catalytic triad is retained, and the essential cysteine is exposed to solvent and addressable by small molecule reagents. These structures and biochemical work contribute to the rapidly expanding literature on Cifs, and direct further studies to better understand the molecular details of the activity of these proteins
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