1,910 research outputs found
Fertilizers boost yields of small grains, grasses and legumes
Corn is king in Iowa. But corn should not be grown continuously. It should be rotated with small grains, clover or alfalfa. Such a rotation insures a good nitrogen level in the soil, cuts down on erosion, and helps keep the soil in good tilth. These factors in turn result in higher corn yields. Too often we neglect or omit our small grains and seedings because they don’t give us the high cash return of corn. One way to make them more profitable is to increase their yields. You can give the yields a real boost with fertilizers.
There are two ways to use fertilizers on small grains and forages— the,right and the wrong. Among other things, the right way involves using the correct kind and amount of fertilizer, applying it effectively to the soil and at the best time. You must know how to do these things. They will determine the returns you will get from your fertilizer. To give you the best possible information on these points, the Iowa Agricultural Experiment Station has conducted several hundred experiments on the fields over the state during the past few years. It is the purpose of this bulletin to give you the information gathered from these experiments along with other pointers to help you in your fertilizer program
Investigation of Structural Damage in a Corrosive Environment: A Case Study
This paper presents the methodology and results of an investigation into the causes of structural damage to a reinforced concrete block wall building in Lake Havasu City, Arizona. The structural damage was in the form of cracking and spalling of the lower courses of the block along the building perimeter. The structural damage to the building had been incorrectly attributed to the Hector Mine Earthquake by another investigator. An evaluation of the response of the building to the estimated level of ground shaking, coupled with site observations, conclusively ruled out the earthquake ground shaking as a cause for the structural damage. Site observations indicated corrosion of reinforcing steel as the fundamental cause for the cracking of the concrete block. Samples of the block, grout, soil, flatwork concrete, and irrigation water were collected during the site investigation. Chemical testing of the soil and water samples, which indicated high levels of sulfates and chlorides, substantiated the site observations that over time the exposure to the soil and water had resulted in an environment that facilitated and resulted in severe corrosion of the steel. This case study highlights the potential for serious structural damage in a corrosive environment, and also cautions against reaching engineering conclusions without a holistic understanding of the problem
Controlled biomineralization of magnetite (Fe<sub>3</sub>O<sub>4</sub>) by <i>Magnetospirillum gryphiswaldense</i>
Results from a study of the chemical composition and micro-structural characteristics of bacterial magnetosomes extracted from the magnetotactic bacterial strain Magnetospirillum gryphiswaldense are presented here. Using high-resolution transmission electron microscopy combined with selected-area electron diffraction and energy dispersive X-ray microanalysis, biogenic magnetite particles isolated from mature cultures were analysed for variations in crystallinity and particle size, as well as chain character and length. The analysed crystals showed a narrow size range (∼14-67 nm) with an average diameter of 46±6.8 nm, cuboctahedral morphologies and typical Gamma type crystal size distributions. The magnetite particles exhibited a high chemical purity (exclusively Fe3O4) and the majority fall within the single-magnetic-domain range
Model anionic block copolymer vesicles provide important design rules for efficient nanoparticle occlusion within calcite
Nanoparticle occlusion within growing crystals is of considerable interest because (i) it can enhance our understanding of biomineralization and (ii) it offers a straightforward route for the preparation of novel nanocomposites. However, robust design rules for efficient occlusion remain elusive. Herein, we report the rational synthesis of a series of silica-loaded poly(glycerol monomethacrylate)-poly(2-hydroxypropyl methacrylate)-poly(ethylene glycol dimethacrylate)-poly(methacrylic acid) tetrablock copolymer vesicles using polymerization-induced self-assembly. The overall vesicle dimensions remain essentially constant for this series; hence systematic variation of the mean degree of polymerization (DP) of the anionic poly(methacrylic acid) steric stabilizer chains provides an unprecedented opportunity to investigate the design rules for efficient nanoparticle occlusion within host inorganic crystals such as calcite. Indeed, the stabilizer DP plays a decisive role in dictating both the extent of occlusion and the calcite crystal morphology: sufficiently long stabilizer chains are required to achieve extents of vesicle occlusion of up to 41 vol %, but overly long stabilizer chains merely lead to significant changes in the crystal morphology, rather than promoting further occlusion. Furthermore, steric stabilizer chains comprising anionic carboxylate groups lead to superior occlusion performance compared to those composed of phosphate, sulfate, or sulfonate groups. Moreover, occluded vesicles are subjected to substantial deformation forces, as shown by the significant change in shape after their occlusion. It is also demonstrated that such vesicles can act as "Trojan horses", enabling the occlusion of non-functional silica nanoparticles within calcite. In summary, this study provides important new physical insights regarding the efficient incorporation of guest nanoparticles within host inorganic crystals
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Measles vaccination and antibody response in autism spectrum disorder
OBJECTIVE: To test the hypothesis that measles vaccination was involved in the pathogenesis of autism spectrum disorders (ASD) as evidenced by signs of a persistent measles infection or abnormally persistent immune response shown by circulating measles virus or raised antibody titres in children with ASD who had been vaccinated against measles, mumps and rubella (MMR) compared with controls. DESIGN: Case-control study, community based. METHODS: A community sample of vaccinated children aged 10-12 years in the UK with ASD (n = 98) and two control groups of similar age, one with special educational needs but no ASD (n = 52) and one typically developing group (n = 90), were tested for measles virus and antibody response to measles in the serum. RESULTS: No difference was found between cases and controls for measles antibody response. There was no dose-response relationship between autism symptoms and antibody concentrations. Measles virus nucleic acid was amplified by reverse transcriptase-PCR in peripheral blood mononuclear cells from one patient with autism and two typically developing children. There was no evidence of a differential response to measles virus or the measles component of the MMR in children with ASD, with or without regression, and controls who had either one or two doses of MMR. Only one child from the control group had clinical symptoms of possible enterocolitis. CONCLUSION: No association between measles vaccination and ASD was shown
Soil Survey of Iowa, Report No . 77—Washington County Soils
Washington County is located in southeastern Iowa in the second tier of counties west of the Mississippi River and in the third tier north of the Missouri state line. It lies partly in the Mississippi loess and partly in the Southern Iowa loess soil areas and hence the soils are all of loessial origin
Soil Survey of Iowa, Report No. 78—Monroe County Soils
Monroe County is located in southern Iowa in the second tier of counties north of the Missouri state line and in the fourth tier west of the Mississippi River. It is entirely within the Southern Iowa loess soil area and the soils are, therefore, practically all of loessial origin. The only drift soils found are those derived from the old Kansan till which has been exposed through the erosion or washing away of the loessial covering
Soil Survey of Iowa, Report No. 71—Sac County Soils
Sac County is located in the northwestern part of Iowa, in the fourth tier of counties south of the Minnesota state line and in the third tier east of the Missouri River. It is partly in the Wisconsin drift soil area and partly in the Missouri loess area. The soils of the county are partly of glacial and partly of loessial origin
Soil Survey of Iowa, Report No. 75—Guthrie County Soils
Guthrie County is located in the west central part of Iowa, in the fourth tier of counties north of the Missouri state line and in the fourth tier east of the Missouri River. It is partly in the Wisconsin drift soil area and partly in the Mississippi loess, the Missouri loess and the Southern Iowa loess soil areas. The soils are, therefore, partly of glacial origin and partly of loessial origin, loess types representing all three loess areas occurring in the county
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