272 research outputs found

    Measurement of the transverse Single Spin Asymmetry of Forward Eta Mesons in p↑+pp^{\uparrow}+p Collisions in PHENIX

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    Polarized p+pp+p collisions provide insight into the structure of the nucleon. ANA_N of eta mesons at forward rapidities are of particular interest, as asymmetries of other mesons observed both by PHENIX and other experiments show significant deviation from zero in the forward region. Several mechanisms have been proposed that attempt to explain these non-zero asymmetries, and a comparison of different probes may further constrain these models. Therefore, measurements of ANA_N with inclusive eta mesons at forward rapidities are an important tool toward understanding the underlying mechanism. Using the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC), we study p↑+pp^{\uparrow}+p collisions. In 2008, the PHENIX experiment collected 5.2 pb−1^{-1} integrated luminosity in p↑+pp^\uparrow+p collisions at s\sqrt{s} = 200 GeV. The asymmetry analysis of eta mesons at forward rapidity will be discussed.Comment: Submitted to American Institute of Physics Conference Proceedings 1441 (2012

    Measurement of the Transverse Single Spin Asymmetry of pp + p↑p^\uparrow →\rightarrow η\eta + XX at s\sqrt{s} = 200 GeV

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    The measurement of transverse single spin asymmetries (ANA_N) provides insight into the structure of the nucleon. Several mechanisms have been proposed that attempt to explain ANA_N based on QCD, and additional measurements of ANA_N for different processes further constrain these models. Using the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC), we study transversely polarized p+p collisions. Results from PHENIX and other experiments show significant asymmetries in the forward region, which could be due to contributions from both the Sivers and the Collins effects. Studying the species as well as the kinematic dependencies of these transverse single spin asymmetries will help to disentangle the origin of the observed asymmetries. Therefore, measurements of ANA_N with inclusive η\eta mesons at forward rapidities are an important tool for the understanding of these asymmetries. In 2008, the PHENIX experiment collected 5.2 pb−1^{-1} integrated luminosity in p↑+pp^\uparrow+p collisions at s\sqrt{s} = 200 GeV. The status of the asymmetry analysis of η\eta mesons at forward rapidity will be shown.Comment: 4 pages, 3 figure

    Corn Silage Variety Trial Archive

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    This report features the available corn silage data from 2003-2017. Crop performance testing results are released annually through the activities of SDSU Extension and the South Dakota Agricultural Experiment Station at SDSU

    Spatial Distribution, Temporal Stability, and Yield Loss Estimates for Annual Grasses and Common Ragweed (Ambrosia artimisiifolia) in a Corn/Soybean Production Field Over Nine Years

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    Weeds generally occur in patches in production fields. Are these patches spatially and temporally stable? Do management recommendations change on the basis of these data? The population density and location of annual grass weeds and common ragweed were examined in a 65-ha corn/soybean production field from 1995 to 2004. Yearly treatment recommendations were developed from field means, medians, and kriging grid cell densities, using the hyperbolic yield loss (YL) equation and published incremental YL values (I ), maximum YL values (A), and YL limits of 5, 10, or 15%. Mean plant densities ranged from 12 to 131 annual grasses m22 and , 1 to 37 common ragweed m22. Median weed densities ranged from 0 to 40 annual grasses m22 and were 0 for common ragweed. The grass I values used to estimate corn YL were 0.1 and 2% and treatment was recommended in only 1 yr when the high I value and either the mean or median density was used. The grass I values used for soybean were 0.7 and 10% and estimated YL was over 10% all years, regardless of I value. The common ragweed I values were 4.5 and 6% for corn and 5.1 and 15.6% for soybean. On the basis of mean densities, fieldwide treatment would have been recommended in 6 of 9 yr but in no years when the median density was used. Recommendations on the basis of grid cell weed density and kriging ranged from . 80% of the field treated for grass weeds in 3 of 4 yr in soybean to , 20% of the field treated for common ragweed in 2002 and 2004 (corn). Grass patches were more stable in time, space, and density than common ragweed patches. Population densities and spatial distribution generally were variable enough so that site-specific information within this field would improve weed management decisions

    Functional conservation of Pax6 regulatory elements in humans and mice demonstrated with a novel transgenic reporter mouse

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    <p>Abstract</p> <p>Background</p> <p>The Pax6 transcription factor is expressed during development in the eyes and in specific CNS regions, where it is essential for normal cell proliferation and differentiation. Mice lacking one or both copies of the <it>Pax6 </it>gene model closely humans with loss-of-function mutations in the <it>PAX6 </it>locus. The sequence of the Pax6/PAX6 protein is identical in mice and humans and previous studies have shown <it>structural </it>conservation of the gene's regulatory regions.</p> <p>Results</p> <p>We generated a transgenic mouse expressing green fluorescent protein (GFP) and neomycin resistance under the control of the entire complement of human <it>PAX6 </it>regulatory elements using a modified yeast artificial chromosome (YAC). Expression of GFP was studied in embryos from 9.5 days on and was confined to cells known to express Pax6. GFP expression was sufficiently strong that expressing cells could be distinguished from non-expressing cells using flow cytometry.</p> <p>Conclusion</p> <p>This work demonstrates the <it>functional </it>conservation of the regulatory elements controlling <it>Pax6/PAX6 </it>expression in mice and humans. The transgene provides an excellent tool for studying the functions of different <it>Pax6/PAX6 </it>regulatory elements in controlling Pax6 expression in animals that are otherwise normal. It will allow the analysis and isolation of cells in which <it>Pax6 </it>is activated, irrespective of the status of the endogenous locus.</p

    DNaseI Hypersensitivity and Ultraconservation Reveal Novel, Interdependent Long-Range Enhancers at the Complex Pax6 Cis-Regulatory Region

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    The PAX6 gene plays a crucial role in development of the eye, brain, olfactory system and endocrine pancreas. Consistent with its pleiotropic role the gene exhibits a complex developmental expression pattern which is subject to strict spatial, temporal and quantitative regulation. Control of expression depends on a large array of cis-elements residing in an extended genomic domain around the coding region of the gene. The minimal essential region required for proper regulation of this complex locus has been defined through analysis of human aniridia-associated breakpoints and YAC transgenic rescue studies of the mouse smalleye mutant. We have carried out a systematic DNase I hypersensitive site (HS) analysis across 200 kb of this critical region of mouse chromosome 2E3 to identify putative regulatory elements. Mapping the identified HSs onto a percent identity plot (PIP) shows many HSs correspond to recognisable genomic features such as evolutionarily conserved sequences, CpG islands and retrotransposon derived repeats. We then focussed on a region previously shown to contain essential long range cis-regulatory information, the Pax6 downstream regulatory region (DRR), allowing comparison of mouse HS data with previous human HS data for this region. Reporter transgenic mice for two of the HS sites, HS5 and HS6, show that they function as tissue specific regulatory elements. In addition we have characterised enhancer activity of an ultra-conserved cis-regulatory region located near Pax6, termed E60. All three cis-elements exhibit multiple spatio-temporal activities in the embryo that overlap between themselves and other elements in the locus. Using a deletion set of YAC reporter transgenic mice we demonstrate functional interdependence of the elements. Finally, we use the HS6 enhancer as a marker for the migration of precerebellar neuro-epithelium cells to the hindbrain precerebellar nuclei along the posterior and anterior extramural streams allowing visualisation of migratory defects in both pathways in Pax6(Sey/Sey) mice

    Identification of Genomic Regions Regulating Pax6 Expression in Embryonic Forebrain Using YAC Reporter Transgenic Mouse Lines

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    The transcription factor Pax6 is a crucial regulator of eye and central nervous system development. Both the spatiotemporal patterns and the precise levels of Pax6 expression are subject to tight control, mediated by an extensive set of cis-regulatory elements. Previous studies have shown that a YAC reporter transgene containing 420 Kb of genomic DNA spanning the human PAX6 locus drives expression of a tau-tagged GFP reporter in mice in a pattern that closely resembles that of endogenous Pax6. Here we have closely compared the pattern of tau-GFP reporter expression at the cellular level in the forebrains and eyes of transgenic mice carrying either complete or truncated versions of the YAC reporter transgene with endogenous Pax6 expression and found several areas where expression of tau-GFP and Pax6 diverge. Some discrepancies are due to differences between the intracellular localization or perdurance of tau-GFP and Pax6 proteins, while others are likely to be a consequence of transcriptional differences. We show that cis-regulatory elements that lie outside the 420 kb fragment of PAX6 are required for correct expression around the pallial-subpallial boundary, in the amygdala and the prethalamus. Further, we found that the YAC reporter transgene effectively labels cells that contribute to the lateral cortical stream, including cells that arise from the pallium and subpallium, and therefore represents a useful tool for studying lateral cortical stream migration

    Landscape Features Impact on Soil Available Water, Corn Biomass, and Gene Expression during the Late Vegetative Stage

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    Crop yields at summit positions of rolling landscapes often are lower than backslope yields. The differences in plant response may be the result of many different factors. We examined corn (Zea mays L.) plant productivity, gene expression, soil water, and nutrient availability in two landscape positions located in historically high (backslope) and moderate (summit and shoulder) yielding zones to gain insight into plant response differences. Growth characteristics, gene expression, and soil parameters (water and N and P content) were determined at the V12 growth stage of corn. At tassel, plant biomass, N content, 13C isotope discrimination (Δ), and soil water was measured. Soil water was 35% lower in the summit and shoulder compared with the lower backslope plots. Plants at the summit had 16% less leaf area, biomass, and N and P uptake at V12 and 30% less biomass at tassel compared with plants from the lower backslope. Transcriptome analysis at V12 indicated that summit and shoulder-grown plants had 496 downregulated and 341 upregulated genes compared with backslope-grown plants. Gene set and subnetwork enrichment analyses indicated alterations in growth and circadian response and lowered nutrient uptake, wound recovery, pest resistance, and photosynthetic capacity in summit and shoulder-grown plants. Reducing plant populations, to lessen demands on available soil water, and applying pesticides, to limit biotic stress, may ameliorate negative water stress responses

    Controlled overexpression of Pax6 in vivo negatively autoregulates the Pax6 locus, causing cell-autonomous defects of late cortical progenitor proliferation with little effect on cortical arealization

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    Levels of expression of the transcription factor Pax6 vary throughout corticogenesis in a rostro-lateral(high) to caudo-medial(low) gradient across the cortical proliferative zone. Previous loss-of-function studies have indicated that Pax6 is required for normal cortical progenitor proliferation, neuronal differentiation, cortical lamination and cortical arealization, but whether and how its level of expression affects its function is unclear. We studied the developing cortex of PAX77 YAC transgenic mice carrying several copies of the human PAX6 locus with its full complement of regulatory regions. We found that PAX77 embryos express Pax6 in a normal spatial pattern, with levels up to three times higher than wild type. By crossing PAX77 mice with a new YAC transgenic line that reports Pax6 expression (DTy54), we showed that increased expression is limited by negative autoregulation. Increased expression reduces proliferation of late cortical progenitors specifically, and analysis of PAX77↔wild-type chimeras indicates that the defect is cell autonomous. We analyzed cortical arealization in PAX77 mice and found that, whereas the loss of Pax6 shifts caudal cortical areas rostrally, Pax6 overexpression at levels predicted to shift rostral areas caudally has very little effect. These findings indicate that Pax6 levels are stabilized by autoregulation, that the proliferation of cortical progenitors is sensitive to altered Pax6 levels and that cortical arealization is not
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