Secondary electron emission due to positive ion bombardment

Stray electrons were produced in the Ames Laboratory linear accelerator by the ion beam striking the target and various other parts of the accelerator. This experiment was done to determine if the stray electrons from parts of the accelerator other than the target could be reduced by using construction materials other than brass. Measurements of the number of electrons produced from several materials, however, indicated that there is no particular advantage in using other materials in place of brass

Considerations in No-Till Small Grain Production

Small grains have become an important component of many crop rotations in Kentucky. Seedbed preparation has typically involved various degrees of tillage in which much of the residue from the previous crop is buried. Under such conditions, a field may be vulnerable to severe soil loss during periods of heavy rainfall until the plants have produced enough vegetative growth to cover the soil surface. Eliminating tillage in small grain production would not only reduce soil loss but also reduce labor cost and increase the timeliness of planting. Interest in no-till small grain production is growing. One survey reports that in 1983 approximately 50,000 acres of small grains were planted using no-tillage in Kentucky. Research information on winter survival, seed placement, residue management, and nitrogen fertilization is now becoming available

Response of Soybeans to Available Potassium in Three Kentucky Soils

Soybeans are produced in nearly all of Kentucky\u27s soil physiographic regions. Soybean response to potassium (K) fertilization and soil test Kvaries with soil type and location. This variation may be associated with the wide range in soil chemical and mineralogical properties among the different regions. Of particular interest are differences in that level of soil test Kat which no further yield response to K fertilizer application would be expected. The main objective of this work was to evaluate the soil K-soybean response relationship on three different field sites where soybean yields were increased by fertilizer K. Several measures of soil K availability were related to soybean yield

Efficiency of Nitrogen Use with Corn on a Tiled and Untiled Soil

Excessive water is one of the largest contributors to the inefficient use of nitrogen in Kentucky. Because of this, nitrogen is often lost by both leaching and,denitrification. The amount, of these losses can be great depending on soil type and weather. Well-drained soils in Kentucky have been shown to lose less nitrogen than poorly drained soils. The nitrogen lost from well drained soils is usually due, to leaching. The nitrogen in the soil, even soon after applying non-nitrate forms of fertilizer N, is mostly in the water soluble nitrate form. When more water falls onto a well-drained soil than the soil can hold, then both water and nitrogen move through the soil below the root zone and are lost for plant use. On poorly-drained soils, the mostly likely method of nitrogen loss is due to denitrification. Nitrogen loss by this mechanism is due to the soil becoming saturated with water (waterlogged) and forcing the air out of the soil. In an effort to survive, some of the microorganisms in the soil take oxygen from nitrate. This process (denitrification) turns the nitrogen into a gas that will diffuse out of the saturated soil and be lost ,into the air. It usually occurs when the soil temperature is above 50°F and the soil is saturated for more than a two day period. If nitrogen fertilizer has been added to the soil prior to the existence of the above conditions, then fairly large amounts of nitrogen can be lost. These conditions are most prevalent in Kentucky on poorly drained soil in April and May. In the past, most farmers have tried to manage this problem by adding excess fertilizer nitrogen to still obtain maximum yields after the loss has been sustained. This management practice may not be economically feasible in the future if nitrogen prices continue to escalate. An alternative management practice used by many farmers is to reduce the amount of nitrogen lost by simply delaying the application of nitrogen until the conditions for denitrification have little chance of occurring. This usually means that the nitrogen is applied in late May or June after the corn has been planted and the risk of waterlogged soil conditions is greatly reduced. To determine the magnitude of such factors, we began an experiment on a poorly drained bottom soil in 1970 to determine 1) the proper rates of preplant nitrogen 2) effectiveness of sidedressing nitrogen and 3) effect of soil tiling on the above two factors

Fragipan Horizon Fragmentation in Slaking Experiments with Amendment Materials and Ryegrass Root Tissue Extracts

Slaking experiments were conducted of fragipan clods immersed in solutions of poultry manure, aerobically digested biosolid waste (ADB), fluidized bed combustion byproduct (FBC), D-H2O, CaCO3, NaF, Na-hexa-metaphosphate, and ryegrass root biomass. The fragipan clods were sampled from the Btx horizon of an Oxyaquic Fragiudalf in Kentucky. Wet sieving aggregate analysis showed significantly better fragmentation in the NaF, Na-hexa-metaphosphate, and ryegrass root solutions with a mean weight diameter range of 15.5-18.8 mm compared to the 44.2-47.9 mm of the poultry manure, ADB, and FBC treatments. Dissolved Si, Al, Fe, and Mn levels released in solution were ambiguous. The poor efficiency of the poultry manure, ADB, and FBC treatments was attributed to their high ionic strength, while the high efficiency of the NaF, Na-hexa-metaphosphate, and rye grass root solutions to their high sodium soluble ratio (SSR). A slaking mechanism is proposed suggesting that aqueous solutions with high SSR penetrate faster into the fragipan capillaries and generate the critical swelling pressure and shearing stress required to rupture the fragipan into several fragments. Additional fragmentation occurs in a followup stage during which potential Si, Al, Fe, and Mn binding agents may be released into solution. Field experiments testing these findings are in progress

Performance of mitochondrial DNA mutations detecting early stage cancer

<p>Abstract</p> <p>Background</p> <p>Mutations in the mitochondrial genome (mtgenome) have been associated with cancer and many other disorders. These mutations can be point mutations or deletions, or admixtures (heteroplasmy). The detection of mtDNA mutations in body fluids using resequencing microarrays, which are more sensitive than other sequencing methods, could provide a strategy to measure mutation loads in remote anatomical sites.</p> <p>Methods</p> <p>We determined the mtDNA mutation load in the entire mitochondrial genome of 26 individuals with different early stage cancers (lung, bladder, kidney) and 12 heavy smokers without cancer. MtDNA was sequenced from three matched specimens (blood, tumor and body fluid) from each cancer patient and two matched specimens (blood and sputum) from smokers without cancer. The inherited wildtype sequence in the blood was compared to the sequences present in the tumor and body fluid, detected using the Affymetrix Genechip^®Human Mitochondrial Resequencing Array 1.0 and supplemented by capillary sequencing for noncoding region.</p> <p>Results</p> <p>Using this high-throughput method, 75% of the tumors were found to contain mtDNA mutations, higher than in our previous studies, and 36% of the body fluids from these cancer patients contained mtDNA mutations. Most of the mutations detected were heteroplasmic. A statistically significantly higher heteroplasmy rate occurred in tumor specimens when compared to both body fluid of cancer patients and sputum of controls, and in patient blood compared to blood of controls. Only 2 of the 12 sputum specimens from heavy smokers without cancer (17%) contained mtDNA mutations. Although patient mutations were spread throughout the mtDNA genome in the lung, bladder and kidney series, a statistically significant elevation of tRNA and ND complex mutations was detected in tumors.</p> <p>Conclusion</p> <p>Our findings indicate comprehensive mtDNA resequencing can be a high-throughput tool for detecting mutations in clinical samples with potential applications for cancer detection, but it is unclear the biological relevance of these detected mitochondrial mutations. Whether the detection of tumor-specific mtDNA mutations in body fluidsy this method will be useful for diagnosis and monitoring applications requires further investigation.</p

New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms