2,361 research outputs found
An investigation into wear characteristics of a direct drilling coulter (opener) : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Agricultural Mechanisation at Massey University
Wear on a promising chisel coulter, developed at Massey University, was considered to be marginally unacceptable. A functional lifespan of approximately 20 hectares for non-rolling blade components necessitated relatively frequent coulter replacement, and thereby incurred increased costs for components and machine downtime. Three experiments were carried out with an improved version of the Massey University chisel coulter concept. The respective objectives were as follows: 1. To determine whether soil particles were passing between the rotating disc and stationary coulter blade components during normal field machine operation. 2. To determine the patterns of coulter blade wear. 3. To compare several selected blade treatments in their abilities to prolong functional coulter blade life. In the first (laboratory) experiment, a stationary test rig was constructed. This closely simulated coulter assembly operation in the field. Measurements of changes in soil particle size with time for "soil" and "no soil" introduction to the disc/blade interface did not detect any soil breakdown which might have indicated a soil "lubrication" effect at that interface. However, observations of the patterns of abrasion and of photographs did indicate that some form of soil "lubrication" had occurred. In the second experiment, a hard-facing welded (Hardcraft 700 over mild steel) and a control treatment (mild steel) were evaluated to establish patterns of wear on a three row field-operating test rig. The former treatment displayed potential for resisting dimensional changes at various stages throughout blade life. The rotating action of the disc against the inner shank of the blade was responsible, in the prevailing conditions, for wear at the inside lower leading edge/wing intersection of the blade. This action eventually accelerated wing wear. The weld bead pattern was modified for use in Run A of Experiment 3 (top pattern); and another pattern (bottom pattern) was designed to prevent possible increased penetration forces associated with the original weld pattern. The third experiment involved evaluation of selected treatments during routine field drilling operations, using a pre-production prototype direct drill. Carbonitrided mild steel blades offered an almost three-fold increase in relative wear resistance (in terms of metal weightloss per hectare) compared to the standard mild steel blades. The carbonitrided treatment also resisted dimensional changes more effectively, and was more cost effective than all other treatments. The influence on wing and shank dimensions exerted by left and right side blade positioning on each coulter assembly, appeared to reflect continual anti-clockwise machine cornering during operation and seed/fertiliser dispersal differences. Coulter wings on the outside of field turns were subjected to greatest wear, as were the shank regions of blades dispersing fertiliser. Lateral and fore/aft positioning of coulter assemblies appeared to have no effects on blade life
The bear circadian clock doesnât âsleepâ during winter dormancy
Most biological functions are synchronized to the environmental light:dark cycle via a circadian timekeeping system. Bears exhibit shallow torpor combined with metabolic suppression during winter dormancy. We sought to confirm that free-running circadian rhythms of body temperature (Tb) and activity were expressed in torpid grizzly (brown) bears and that they were functionally responsive to environmental light. We also measured activity and ambient light exposures in denning wild bears to determine if rhythms were evident and what the photic conditions of their natural dens were. Lastly, we used cultured skin fibroblasts obtained from captive torpid bears to assess molecular clock operation in peripheral tissues. Circadian parameters were estimated using robust wavelet transforms and maximum entropy spectral analyses
San Francisco Delta Risk Assessment Year 1 Report Appendices
The Relative Contributions of Contaminants to Environmental Risk in the Upper San Francisco Estuary: Progress Report Year 1: Appendices
Prepared for: The Metropolitan Water District of Southern California
Prepared by: Wayne G. Landis, Steven R. Eikenbary, Ethan A. Brown, Colter P. Lemons, Emma E. Sharpe, and April J. Markiewicz
Institute of Environmental Toxicology, Huxley College of the Environment
Western Washington University
Bellingham, WA 98225
June 30, 202
San Francisco Delta Risk Assessment Year 1 Report
The Relative Contributions of Contaminants to Environmental Risk in the Upper San Francisco Estuary: Progress Report Year 1
Prepared for: The Metropolitan Water District of Southern California
Prepared by: Wayne G. Landis, Steven R. Eikenbary, Ethan A. Brown, Colter P. Lemons, Emma E. Sharpe, and April J. Markiewicz
Institute of Environmental Toxicology, Huxley College of the Environment
Western Washington University
Bellingham, WA 98225
June 30, 202
Ischemic stroke risk, smoking, and the genetics of inflammation in a biracial population: the stroke prevention in young women study
<p>Abstract</p> <p>Background</p> <p>Although cigarette smoking is a well-established risk factor for vascular disease, the genetic mechanisms that link cigarette smoking to an increased incidence of stroke are not well understood. Genetic variations within the genes of the inflammatory pathways are thought to partially mediate this risk. Here we evaluate the association of several inflammatory gene single nucleotide polymorphisms (SNPs) with ischemic stroke risk among young women, further stratified by current cigarette smoking status.</p> <p>Methods</p> <p>A population-based case-control study of stroke among women aged 15â49 identified 224 cases of first ischemic stroke (47.3% African-American) and 211 age-comparable control subjects (43.1% African-American). Several inflammatory candidate gene SNPs chosen through literature review were genotyped in the study population and assessed for association with stroke and interaction with smoking status.</p> <p>Results</p> <p>Of the 8 SNPs (across 6 genes) analyzed, only <it>IL6 </it>SNP rs2069832 (allele C, African-American frequency = 92%, Caucasian frequency = 55%) was found to be significantly associated with stroke using an additive model, and this was only among African-Americans (age-adjusted: OR = 2.2, 95% CI = 1.0â5.0, p = 0.049; risk factor adjusted: OR = 2.5, 95% CI = 1.0â6.5, p = 0.05). When stratified by smoking status, two SNPs demonstrated statistically significant gene-environment interactions. First, the T allele (frequency = 5%) of <it>IL6 </it>SNP rs2069830 was found to be protective among non-smokers (OR = 0.30, 95% CI = 0.11â.082, p = 0.02), but not among smokers (OR = 1.63, 95% CI = 0.48â5.58, p = 0.43); genotype by smoking interaction (p = 0.036). Second, the C allele (frequency = 39%) of <it>CD14 </it>SNP rs2569190 was found to increase risk among smokers (OR = 2.05, 95% CI = 1.09â3.86, p = 0.03), but not among non-smokers (OR = 0.93, 95% CI = 0.62â1.39, p = 0.72); genotype by smoking interaction (p = 0.039).</p> <p>Conclusion</p> <p>This study demonstrates that inflammatory gene SNPs are associated with early-onset ischemic stroke among African-American women (<it>IL6</it>) and that cigarette smoking may modulate stroke risk through a gene-environment interaction (<it>IL6 and CD14</it>). Our finding replicates a prior study showing an interaction with smoking and the C allele of <it>CD14 </it>SNP rs2569190.</p
Review of quantitative empirical evaluations of technology for people with visual impairments
Addressing the needs of visually impaired people is of continued interest in Human Computer Interaction (HCI) research. Yet, one of the major challenges facing researchers in this field continues to be how to design adequate quantitative empirical evaluation for these users in HCI. In this paper, we analyse a corpus of 178 papers on technologies designed for people with visual impairments, published since 1988, and including at least one quantitative empirical evaluation (243 evaluations in total). To inform future research in this area, we provide
an overview, historic trends and a unified terminology to design and report quantitative empirical evaluations. We identify open issues and propose a set of guidelines to address them. Our analysis aims to facilitate and stimulate future research on this topic
Report from UCSF.
Table S1. Body weights (kg) of captive bears just prior to entering winter dormancy. (PDF 630Â kb
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Enhancer RNAs participate in androgen receptor-driven looping that selectively enhances gene activation
The androgen receptor (AR) is a key factor that regulates the behavior and fate of prostate cancer cells. The AR-regulated network is activated when AR binds enhancer elements and modulates specific enhancerâpromoter looping. Kallikrein-related peptidase 3 (KLK3), which codes for prostate-specific antigen (PSA), is a well-known AR-regulated gene and its upstream enhancers produce bidirectional enhancer RNAs (eRNAs), termed KLK3e. Here, we demonstrate that KLK3e facilitates the spatial interaction of the KLK3 enhancer and the KLK2 promoter and enhances long-distance KLK2 transcriptional activation. KLK3e carries the core enhancer element derived from the androgen response element III (ARE III), which is required for the interaction of AR and Mediator 1 (Med1). Furthermore, we show that KLK3e processes RNA-dependent enhancer activity depending on the integrity of core enhancer elements. The transcription of KLK3e was detectable and its expression is significantly correlated with KLK3 and KLK2 in human prostate tissues. Interestingly, RNAi silencing of KLK3e resulted in a modest negative effect on prostate cancer cell proliferation. Accordingly, we report that an androgen-induced eRNA scaffolds the AR-associated protein complex that modulates chromosomal architecture and selectively enhances AR-dependent gene expression
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Polycomb-independent activity of EZH2 in castration resistant prostate cancer
LSST Science Book, Version 2.0
A survey that can cover the sky in optical bands over wide fields to faint
magnitudes with a fast cadence will enable many of the exciting science
opportunities of the next decade. The Large Synoptic Survey Telescope (LSST)
will have an effective aperture of 6.7 meters and an imaging camera with field
of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over
20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with
fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a
total point-source depth of r~27.5. The LSST Science Book describes the basic
parameters of the LSST hardware, software, and observing plans. The book
discusses educational and outreach opportunities, then goes on to describe a
broad range of science that LSST will revolutionize: mapping the inner and
outer Solar System, stellar populations in the Milky Way and nearby galaxies,
the structure of the Milky Way disk and halo and other objects in the Local
Volume, transient and variable objects both at low and high redshift, and the
properties of normal and active galaxies at low and high redshift. It then
turns to far-field cosmological topics, exploring properties of supernovae to
z~1, strong and weak lensing, the large-scale distribution of galaxies and
baryon oscillations, and how these different probes may be combined to
constrain cosmological models and the physics of dark energy.Comment: 596 pages. Also available at full resolution at
http://www.lsst.org/lsst/sciboo
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