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Sample records for allelic richness ar

  1. Ar-40/Ar-39 Ages for Maskelynites and K-Rich Melt from Olivine-Rich Lithology in (Kanagawa) Zagami

    NASA Technical Reports Server (NTRS)

    Park, J.; Herzog, G. F.; Nyquist, L. E.; Lindsay, F.; Turrin, B.; Swisher, C. C., III; Delaney, J. S.; Shih, C.-Y.; Niihara, T.; Misawa, K.

    2013-01-01

    We report Ar/Ar release patterns for small maskelynite grains and samples of a K-rich phase separated from the basaltic shergottite Zagami. The purpose of the work is to investigate the well-known discrepancy between published Ar/Ar ages of Zagami, >200 Ma, and its age of approx. 170 Ma as determined by other methods [1-6]. Niihara et al. [7] divide less abundant darker material present in Zagami into an olivine-rich lithology (ORL), from which most of our samples came, and a pyroxene-rich one (Dark Mottled-Lithology: DML) [8, 9]. ORL consists of vermicular fayalitic olivine, coarse-grained pyroxene, maskelynite, and a glassy phase exceptionally rich in K (up to 8.5 wt%), Al, and Si, but poor in Fe and Mg. The elemental composition suggests a late-stage melt, i.e., residual material that solidified late in a fractional crystallization sequence. Below we refer to it as "K-rich melt." The K-rich melt contains laths of captured olivine, Ca-rich pyroxene, plagioclase, and opaques. It seemed to offer an especially promising target for Ar-40/Ar-39 dating.

  2. 40Ar/39Ar and cosmic ray exposure ages of plagioclase-rich lithic fragments from Apollo 17 regolith, 78461

    NASA Astrophysics Data System (ADS)

    Das, J. P.; Baldwin, S. L.; Delano, J. W.

    2016-01-01

    Argon isotopic data is used to assess the potential of low-mass samples collected by sample return missions on planetary objects (e.g., Moon, Mars, asteroids), to reveal planetary surface processes. We report the first 40Ar/39Ar ages and 38Ar cosmic ray exposure (CRE) ages, determined for eleven submillimeter-sized (ranging from 0.06 to 1.2 mg) plagioclase-rich lithic fragments from Apollo 17 regolith sample 78461 collected at the base of the Sculptured Hills. Total fusion analysis was used to outgas argon from the lithic fragments. Three different approaches were used to determine 40Ar/39Ar ages and illustrate the sensitivity of age determination to the choice of trapped (40Ar/36Ar)t. 40Ar/39Ar ages range from ~4.0 to 4.4 Ga with one exception (Plag#10). Surface CRE ages, based on 38Ar, range from ~1 to 24 Ma. The relatively young CRE ages suggest recent re-working of the upper few centimeters of the regolith. The CRE ages may result from the effect of downslope movement of materials to the base of the Sculptured Hills from higher elevations. The apparent 40Ar/39Ar age for Plag#10 is >5 Ga and yielded the oldest CRE age (i.e., ~24 Ma). We interpret this data to indicate the presence of parentless 40Ar in Plag#10, originating in the lunar atmosphere and implanted in lunar regolith by solar wind. Based on a chemical mixing model, plagioclase compositions, and 40Ar/39Ar ages, we conclude that lithic fragments originated from Mg-suite of highland rocks, and none were derived from the mare region.

  3. Mineralogy and Ar-Ar Age of the Tarahumara IIE Iron, with Reference to the Origin of Alkali-Rich Materials

    NASA Technical Reports Server (NTRS)

    Takeda, Hiroshi; Bogard, Donald D.; Otsuki, Mayumi; Ishii, Teruaki

    2003-01-01

    Silicate inclusions in nine known IIE irons show diversity in mineralogy, and Colomera, Kodaikanal, Elga and Miles contain alkali-rich silicate inclusions. Bogard et al. showed evidence of a complex parent body evolution for IIE irons based on Ar-39-Ar-40 ages. Colomera contained a sanidine-rich surface inclusion and the K-enrichment trends in the Na-rich inclusions are different from those of other IIEs. To elucidate the origin of K-rich materials, we studied the mineralogy and Ar-Ar age of silicate inclusions from the Tarahumara IIE iron meteorite.

  4. sup 40 Ar- sup 39 Ar and K-Ar dating of K-rich rocks from the Roccamonfina volcano, Roman Comagmatic Region, Italy

    SciTech Connect

    Di Brozolo, F.R.; Di Girolamo, P.; Turi, B.; Oddone, M. )

    1988-06-01

    Roccamonfina is the northernmost Volcano of the Campanian area of the K-rich Roman comagmatic Region of Italy. It erupted a huge amount of pyroclastics and lavas belonging to both the Leucite-Basanite and Leucitite Series (LBLS) and the Shoshonite Series (SS), spread over an area of about 300 km{sup 2}. The above series correspond to the High-K Series (HKS) and Low-K Series (LKS) of Appleton (1971), respectively. {sup 40}Ar-{sup 39}Ar and K-Ar dating of samples from both series gave ages ranging from 0.656 to 0.096 Ma for the SS and from 1.03( ) to 0.053 Ma for the LBLS. These results indicate that the products of the two series were outpoured together at least between 0.7 and 0.1 Ma age, i.e. during both the so-called pre-caldera phase and the post-caldera phase of activity. The latest products of the volcanism at Roccamonfina were erupted just before the deposition of the Grey Campanian Ignimbrite, which erupted from vents located about 50 km to the south in the Phlegrean Fields near Naples and has an age of about 33,000 years. Taking into account all the available all the available radiometric data the authors conclude that Roccamonfina was active between 1.5 and 0.05 Ma ago, in excellent agreement with the stratigraphic evidence. In this same time span is concentrated the activity of all the centers of the Roman Region north of Naples.

  5. Suppression among alleles encoding nucleotide-binding-leucine-rich repeat resistance proteins interferes with resistance in F1 hybrid and allele-pyramided wheat plants.

    PubMed

    Stirnweis, Daniel; Milani, Samira D; Brunner, Susanne; Herren, Gerhard; Buchmann, Gabriele; Peditto, David; Jordan, Tina; Keller, Beat

    2014-09-01

    The development of high-yielding varieties with broad-spectrum durable disease resistance is the ultimate goal of crop breeding. In plants, immune receptors of the nucleotide-binding-leucine-rich repeat (NB-LRR) class mediate race-specific resistance against pathogen attack. When employed in agriculture this type of resistance is often rapidly overcome by newly adapted pathogen races. The stacking of different resistance genes or alleles in F1 hybrids or in pyramided lines is a promising strategy for achieving more durable resistance. Here, we identify a molecular mechanism which can negatively interfere with the allele-pyramiding approach. We show that pairwise combinations of different alleles of the powdery mildew resistance gene Pm3 in F1 hybrids and stacked transgenic wheat lines can result in suppression of Pm3-based resistance. This effect is independent of the genetic background and solely dependent on the Pm3 alleles. Suppression occurs at the post-translational level, as levels of RNA and protein in the suppressed alleles are unaffected. Using a transient expression system in Nicotiana benthamiana, the LRR domain was identified as the domain conferring suppression. The results of this study suggest that the expression of closely related NB-LRR resistance genes or alleles in the same genotype can lead to dominant-negative interactions. These findings provide a molecular explanation for the frequently observed ineffectiveness of resistance genes introduced from the secondary gene pool into polyploid crop species and mark an important step in overcoming this limitation.

  6. 40 CFR 721.10025 - 10H-Phenothiazine, ar, ar′-(C9-rich C8-10-branched alkyl) derivs.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false 10H-Phenothiazine, ar, arâ²-(C9-rich... Significant New Uses for Specific Chemical Substances § 721.10025 10H-Phenothiazine, ar, ar′-(C9-rich C8-10... chemical substances identified as 10H-phenothiazine, ar, ar′-(C9-rich C8-10-branched alkyl) derivs (PMN...

  7. 40 CFR 721.10025 - 10H-Phenothiazine, ar, ar′-(C9-rich C8-10-branched alkyl) derivs.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false 10H-Phenothiazine, ar, arâ²-(C9-rich... Significant New Uses for Specific Chemical Substances § 721.10025 10H-Phenothiazine, ar, ar′-(C9-rich C8-10... chemical substances identified as 10H-phenothiazine, ar, ar′-(C9-rich C8-10-branched alkyl) derivs (PMN...

  8. 40 CFR 721.10025 - 10H-Phenothiazine, ar, ar′-(C9-rich C8-10-branched alkyl) derivs.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false 10H-Phenothiazine, ar, arâ²-(C9-rich... Significant New Uses for Specific Chemical Substances § 721.10025 10H-Phenothiazine, ar, ar′-(C9-rich C8-10... chemical substances identified as 10H-phenothiazine, ar, ar′-(C9-rich C8-10-branched alkyl) derivs (PMN...

  9. 40 CFR 721.10025 - 10H-Phenothiazine, ar, ar′-(C9-rich C8-10-branched alkyl) derivs.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false 10H-Phenothiazine, ar, arâ²-(C9-rich... Significant New Uses for Specific Chemical Substances § 721.10025 10H-Phenothiazine, ar, ar′-(C9-rich C8-10... chemical substances identified as 10H-phenothiazine, ar, ar′-(C9-rich C8-10-branched alkyl) derivs (PMN...

  10. 40 CFR 721.10025 - 10H-Phenothiazine, ar, ar′-(C9-rich C8-10-branched alkyl) derivs.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false 10H-Phenothiazine, ar, arâ²-(C9-rich... Significant New Uses for Specific Chemical Substances § 721.10025 10H-Phenothiazine, ar, ar′-(C9-rich C8-10... chemical substances identified as 10H-phenothiazine, ar, ar′-(C9-rich C8-10-branched alkyl) derivs (PMN...

  11. Ar irradiated Cr rich Ni alloy studied using positron annihilation spectroscopy

    NASA Astrophysics Data System (ADS)

    Saini, Sanjay; Menon, Ranjini; Sharma, S. K.; Srivastava, A. P.; Mukherjee, S.; Nabhiraj, P. Y.; Pujari, P. K.; Srivastava, D.; Dey, G. K.

    2016-10-01

    The present study focuses on understanding the effect of Ar ion irradiation at room temperature on Cr rich Ni-Cr alloy. The alloy is irradiated with Ar9+ ions (energy 315 keV) for total dose varying from 9.3 × 1014 to 2.3 × 1016 ion/cm2. The changes in the microstructure of the irradiated samples have been characterized by depth dependent Doppler broadening of annihilation radiation (DBAR) measurements using a slow positron beam facility. The variation in S-E profiles as a function of total dose corroborated with S-W curves indicates that the type of defects is also varied with the increase in total dose. The S-E profiles have been fitted using variable energy positron fit (VEPFIT) program considering a three layer structure for the irradiated samples. Estimated displacement damage profile as a function of increasing dose has been analyzed and a possible mechanism has been attributed to explain the observations made from S-parameter variation.

  12. 40 CFR 721.10023 - Benzenamine, N-phenyl-, ar ar′-(C9-rich C88-10-branched alkyl) derivs.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzenamine, N-phenyl-, ar arâ²-(C9... Significant New Uses for Specific Chemical Substances § 721.10023 Benzenamine, N-phenyl-, ar ar′-(C9-rich C88...) The chemical substance identified as benzenamine, N-phenyl-, ar,ar′-(C9-rich C8-10-branched...

  13. 40 CFR 721.10023 - Benzenamine, N-phenyl-, ar ar′-(C9-rich C8-10-branched alkyl) derivs.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Benzenamine, N-phenyl-, ar arâ²-(C9... Significant New Uses for Specific Chemical Substances § 721.10023 Benzenamine, N-phenyl-, ar ar′-(C9-rich C8...) The chemical substance identified as benzenamine, N-phenyl-, ar,ar′-(C9-rich C8-10-branched...

  14. 40 CFR 721.10023 - Benzenamine, N-phenyl-, ar ar′-(C9-rich C8-10-branched alkyl) derivs.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Benzenamine, N-phenyl-, ar arâ²-(C9... Significant New Uses for Specific Chemical Substances § 721.10023 Benzenamine, N-phenyl-, ar ar′-(C9-rich C8...) The chemical substance identified as benzenamine, N-phenyl-, ar,ar′-(C9-rich C8-10-branched...

  15. 40 CFR 721.10023 - Benzenamine, N-phenyl-, ar ar′-(C9-rich C88-10-branched alkyl) derivs.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Benzenamine, N-phenyl-, ar arâ²-(C9... Significant New Uses for Specific Chemical Substances § 721.10023 Benzenamine, N-phenyl-, ar ar′-(C9-rich C88...) The chemical substance identified as benzenamine, N-phenyl-, ar,ar′-(C9-rich C8-10-branched...

  16. 40 CFR 721.10023 - Benzenamine, N-phenyl-, ar ar′-(C9-rich C8-10-branched alkyl) derivs.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Benzenamine, N-phenyl-, ar arâ²-(C9... Significant New Uses for Specific Chemical Substances § 721.10023 Benzenamine, N-phenyl-, ar ar′-(C9-rich C8...) The chemical substance identified as benzenamine, N-phenyl-, ar,ar′-(C9-rich C8-10-branched...

  17. 40 CFR 721.10024 - 10H-Phenothiazine, ar-(C9-rich C8-10-branched alkyl) derivs.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false 10H-Phenothiazine, ar-(C9-rich C8-10... New Uses for Specific Chemical Substances § 721.10024 10H-Phenothiazine, ar-(C9-rich C8-10-branched... substance identified as 10H-phenothiazine, ar-(C9-rich C8-10-branched alkyl) derivs (PMN P-01-771; CAS...

  18. 40 CFR 721.10024 - 10H-Phenothiazine, ar-(C9-rich C8-10-branched alkyl) derivs.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false 10H-Phenothiazine, ar-(C9-rich C8-10... New Uses for Specific Chemical Substances § 721.10024 10H-Phenothiazine, ar-(C9-rich C8-10-branched... substance identified as 10H-phenothiazine, ar-(C9-rich C8-10-branched alkyl) derivs (PMN P-01-771; CAS...

  19. 40 CFR 721.10024 - 10H-Phenothiazine, ar-(C9-rich C8-10-branched alkyl) derivs.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false 10H-Phenothiazine, ar-(C9-rich C8-10... New Uses for Specific Chemical Substances § 721.10024 10H-Phenothiazine, ar-(C9-rich C8-10-branched... substance identified as 10H-phenothiazine, ar-(C9-rich C8-10-branched alkyl) derivs (PMN P-01-771; CAS...

  20. 40 CFR 721.10024 - 10H-Phenothiazine, ar-(C9-rich C8-10-branched alkyl) derivs.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false 10H-Phenothiazine, ar-(C9-rich C8-10... New Uses for Specific Chemical Substances § 721.10024 10H-Phenothiazine, ar-(C9-rich C8-10-branched... substance identified as 10H-phenothiazine, ar-(C9-rich C8-10-branched alkyl) derivs (PMN P-01-771; CAS...

  1. 40 CFR 721.10024 - 10H-Phenothiazine, ar-(C9-rich C8-10-branched alkyl) derivs.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false 10H-Phenothiazine, ar-(C9-rich C8-10... New Uses for Specific Chemical Substances § 721.10024 10H-Phenothiazine, ar-(C9-rich C8-10-branched... substance identified as 10H-phenothiazine, ar-(C9-rich C8-10-branched alkyl) derivs (PMN P-01-771; CAS...

  2. Meiotic recombination generates rich diversity in NK cell receptor genes, alleles, and haplotypes

    PubMed Central

    Norman, Paul J.; Abi-Rached, Laurent; Gendzekhadze, Ketevan; Hammond, John A.; Moesta, Achim K.; Sharma, Deepti; Graef, Thorsten; McQueen, Karina L.; Guethlein, Lisbeth A.; Carrington, Christine V.F.; Chandanayingyong, Dasdayanee; Chang, Yih-Hsin; Crespí, Catalina; Saruhan-Direskeneli, Güher; Hameed, Kamran; Kamkamidze, Giorgi; Koram, Kwadwo A.; Layrisse, Zulay; Matamoros, Nuria; Milà, Joan; Park, Myoung Hee; Pitchappan, Ramasamy M.; Ramdath, D. Dan; Shiau, Ming-Yuh; Stephens, Henry A.F.; Struik, Siske; Tyan, Dolly; Verity, David H.; Vaughan, Robert W.; Davis, Ronald W.; Fraser, Patricia A.; Riley, Eleanor M.; Ronaghi, Mostafa; Parham, Peter

    2009-01-01

    Natural killer (NK) cells contribute to the essential functions of innate immunity and reproduction. Various genes encode NK cell receptors that recognize the major histocompatibility complex (MHC) Class I molecules expressed by other cells. For primate NK cells, the killer-cell immunoglobulin-like receptors (KIR) are a variable and rapidly evolving family of MHC Class I receptors. Studied here is KIR3DL1/S1, which encodes receptors for highly polymorphic human HLA-A and -B and comprises three ancient allelic lineages that have been preserved by balancing selection throughout human evolution. While the 3DS1 lineage of activating receptors has been conserved, the two 3DL1 lineages of inhibitory receptors were diversified through inter-lineage recombination with each other and with 3DS1. Prominent targets for recombination were D0-domain polymorphisms, which modulate enhancer function, and dimorphism at position 283 in the D2 domain, which influences inhibitory function. In African populations, unequal crossing over between the 3DL1 and 3DL2 genes produced a deleted KIR haplotype in which the telomeric “half” was reduced to a single fusion gene with functional properties distinct from its 3DL1 and 3DL2 parents. Conversely, in Eurasian populations, duplication of the KIR3DL1/S1 locus by unequal crossing over has enabled individuals to carry and express alleles of all three KIR3DL1/S1 lineages. These results demonstrate how meiotic recombination combines with an ancient, preserved diversity to create new KIR phenotypes upon which natural selection acts. A consequence of such recombination is to blur the distinction between alleles and loci in the rapidly evolving human KIR gene family. PMID:19411600

  3. A high-fat diet and the threonine-encoding allele (Thr54) polymorphism of fatty acid–binding protein 2 reduce plasma triglyceride–rich lipoproteins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Thr54 allele of the fatty acid binding protein 2 (FABP2) DNA polymorphism is associated with increased triglyceride-rich lipoproteins and insulin resistance. We investigated whether the triglyceride-rich lipoprotein response to diets of varied fat content is affected by the fatty acid binding pr...

  4. Genetic Diversity and Allelic Frequency of Glutamate-Rich Protein (GLURP) in Plasmodium falciparum Isolates from Sub-Saharan Africa

    PubMed Central

    Duru, Kimberley C; Thomas, Bolaji N

    2014-01-01

    Glutamate-rich protein is a Plasmodium falciparum (Pf) antigen found in all stages of the parasite and has been reported to induce clinical immunity. The R0 and R2 regions have been found to exhibit a high degree of conservation, therefore serving as a good vaccine design material. We assayed the genetic diversity of Pf glurp genes in the R0 and R2 regions, as well as evaluated the role of seasonality on allelic frequency. A total of 402 genomic DNA samples, extracted from filter paper blood samples, were screened by nested polymerase chain reaction (PCR) analysis of Pf glurp R0 and R2 regions, in addition to fragment analysis of the polymorphic regions to identify allelic diversity of the parasite population. We found an extensive heterogeneity in the R2 region in general, and this heterogeneity is seasonally dependent, indicative of region plasticity. The R0 region displayed genetic conservation, as expected. We conclude that positive genotyping results with glurp R0 region should be seen as indicative of an active Pf infection, requiring adequate treatment. In addition, we advocate extending the possibility that an R0 region genotypic positivity could serve as diagnostic tool, thereby reducing cases of untreated or poorly treated infection, contributory to recrudescence or treatment failure. PMID:25452699

  5. Development of β-carotene rich maize hybrids through marker-assisted introgression of β-carotene hydroxylase allele.

    PubMed

    Muthusamy, Vignesh; Hossain, Firoz; Thirunavukkarasu, Nepolean; Choudhary, Mukesh; Saha, Supradip; Bhat, Jayant S; Prasanna, Boddupalli M; Gupta, Hari S

    2014-01-01

    Development of vitamin A-rich cereals can help in alleviating the widespread problem of vitamin A deficiency. We report here significant enhancement of kernel β-carotene in elite maize genotypes through accelerated marker-assisted backcross breeding. A favourable allele (543 bp) of the β-carotene hydroxylase (crtRB1) gene was introgressed in the seven elite inbred parents, which were low (1.4 µg/g) in kernel β-carotene, by using a crtRB1-specific DNA marker for foreground selection. About 90% of the recurrent parent genome was recovered in the selected progenies within two backcross generations. Concentration of β-carotene among the crtRB1-introgressed inbreds varied from 8.6 to 17.5 µg/g - a maximum increase up to 12.6-fold over recurrent parent. The reconstituted hybrids developed from improved parental inbreds also showed enhanced kernel β-carotene as high as 21.7 µg/g, compared to 2.6 µg/g in the original hybrid. The reconstituted hybrids evaluated at two locations possessed similar grain yield to that of original hybrids. These β-carotene enriched high yielding hybrids can be effectively utilized in the maize biofortification programs across the globe.

  6. Mineralogy, Petrology, Chemistry, and Ar-39 - Ar-40 and Ages of the Caddo County IAB Iron: Evidence for Early Partial Melt Segregation of a Gabbro Area Rich in Plagioclase-Diopside

    NASA Technical Reports Server (NTRS)

    Takeda, Hiroshi; Bogard, Donald D.; Mittlefehldt, David W.; Garrison, Daniel H.

    2000-01-01

    We found coarse-grained gabbroic material rich in plagioclase and diopside in the Caddo County IAB iron meteorite. The polished thin sections studied were made from areas rich in Al and Ca detected by a micro-focus X-ray fluorescence (XRF) mapping technique. The gabbro is not a clast within a breccia, but rather this area is located mainly at silicate-metal boundaries only a few cm away from an area with fine-grained, ultramafic silicate similar to winonaites. Medium-grained orthopyroxene and olivine are found in transitional areas showing no disturbance of their crystalline textures. A vein-like region, starting at the area rich in fine-grained mafic silicate, extends towards the gabbroic area with a gradual increase in abundance of plagioclase and diopside. This texture and our accumulated knowledge of the formation mechanism of IAB/winonaltes meteorites, suggest that the gabbroic materials were formed by inhomogeneous segregation of partial melts of chondritic source materials. Compositional data on two mineralogically distinct samples of the gabbro-rich portion of the inclusion were obtained by INAA. Compared to an average of LAB silicate inclusions or winonaites, the Caddo County gabbro is enriched in the incompatible lithophile elements Na, Ca, Sc, REE and Hf, which is consistent with a melt origin for the gabbro. The cosmogenic space exposure age of Caddo County (511 Ma) is significantly younger than exposure ages of some other IAB meteorites, An 39Ar-40Ar age determination of the gabbroic material indicates a series of upward steps in age from 4.516 Ga to 4.523 Ga, with a few high temperature ages up to 4.54 Ga. The older age could approximate the primary recrystallization age of silicates. The stepped Ar age spectrum may indicate differences in Ar closure temperatures during slow cooling of -2-20'C/Myr in the parent body. Alternatively, the younger Ar-Ar ages may date a shock event which occurred while Caddo County was hot and which also created textures

  7. Denitrification in nitrate-rich streams: Application of N2:Ar and 15N-tracer methods in intact cores

    USGS Publications Warehouse

    Smith, L.K.; Voytek, M.A.; Böhlke, J.K.; Harvey, J.W.

    2006-01-01

    Rates of benthic denitrification were measured using two techniques, membrane inlet mass spectrometry (MIMS) and isotope ratio mass spectrometry (IRMS), applied to sediment cores from two NO3--rich streams draining agricultural land in the upper Mississippi River Basin. Denitrification was estimated simultaneously from measurements of N 2:Ar (MIMS) and 15N[N2] (IRMS) after the addition of low-level 15NO3- tracer ( 15N:N = 0.03-0.08) in stream water overlying intact sediment cores. Denitrification rates ranged from about 0 to 4400 lmol N??m -2??h-1 in Sugar Creek and from 0 to 1300 ??mol N??m-2??h-1 in Iroquois River, the latter of which possesses greater streamflow discharge and a more homogeneous streambed and water column. Within the uncertainties of the two techniques, there is good agreement between the MIMS and IRMS results, which indicates that the production of N2 by the coupled process of nitrification/denitrification was relatively unimportant and surface-water NO3- was the dominant source of NO3- for benthic denitrification in these streams. Variation in stream NO3- concentration (from about 20 ??mol/L during low discharge to 1000 ??mol/L during high discharge) was a significant control of benthic denitrification rates, judging from the more abundant MIMS data. The interpretation that NO3- concentration directly affects denitrification rate was corroborated by increased rates of denitrification in cores amended with NO 3-. Denitrification in Sugar Creek removed ???11% per day of the instream NO3- in late spring and removed roughly 15-20% in late summer. The fraction of NO3- removed in Iroquois River was less than that of Sugar Creek. Although benthic denitrification rates were relatively high during periods of high stream flow, when NO3 concentrations were also high, the increase in benthic denitrification could not compensate for the much larger increase in stream NO3- fluxes during high flow. Consequently, fractional NO3- losses were relatively low

  8. Argon, oxygen, and boron isotopic evidence documenting 40ArE accumulation in phengite during water-rich high-pressure subduction metasomatism of continental crust

    NASA Astrophysics Data System (ADS)

    Menold, Carrie A.; Grove, Marty; Sievers, Natalie E.; Manning, Craig E.; Yin, An; Young, Edward D.; Ziegler, Karen

    2016-07-01

    The Luliang Shan area of the North Qaidam high pressure (HP) to ultrahigh pressure (UHP) metamorphic terrane in northwestern China features thick, garnet- and phengite-rich metasomatic selvages that formed around gneiss-hosted mafic eclogite blocks during HP conditions. Here we present new 40Ar/39Ar, δ18 O, and δ11 B results from a previously studied 30 m, 18 sample traverse that extends from the host gneiss into a representative eclogite block. Previous thermobarometry and new mica-quartz oxygen isotope thermometry from the traverse reveal that the phengite-rich selvage formed at temperatures similar to those recorded by the eclogites at peak pressure. Quartz and white mica δ18 O data from the selvage cannot be explained by simple mixing of gneiss and eclogite, and indicate a fluid/rock ratio >1 during regional-scale infiltration of high δ18 O (ca. 14‰) fluids. Heavy δ18 O overgrowths of metamorphic zircon over lighter δ18 O detrital grains indicate that the gneiss was similarly affected. Starkly contrasting boron content and δ11 B compositions for the host gneiss and the selvage also cannot be explained by local-scale devolatilization of the gneiss to form the selvage. Instead, the boron systematics are best attributed to two distinct phases of fluid infiltration: (1) low-boron selvage phengite with δ11 B from -10 to -30‰ grew under HP conditions; and (2) tourmaline and boron-rich muscovite with generally positive δ11 B crystallized in the host gneiss under subsequent lower pressure epidote-amphibolite facies conditions as the Luliang Shan gneiss terrane was exhumed past shallower portions of the subduction channel. Consistent with observations made worldwide, we were able to identify uptake of excess argon (40ArE) in phengite as a high pressure phenomenon. Phengite 40Ar/39Ar ages from massive eclogite exceed the ca. 490 Ma zircon U-Pb age of eclogite metamorphism by a factor of 1.5. However, phengite ages from the more permeable schistose selvage

  9. Effects of sample size, number of markers, and allelic richness on the detection of spatial genetic pattern

    USGS Publications Warehouse

    Landguth, Erin L.; Gedy, Bradley C.; Oyler-McCance, Sara J.; Garey, Andrew L.; Emel, Sarah L.; Mumma, Matthew; Wagner, Helene H.; Fortin, Marie-Josée; Cushman, Samuel A.

    2012-01-01

    The influence of study design on the ability to detect the effects of landscape pattern on gene flow is one of the most pressing methodological gaps in landscape genetic research. To investigate the effect of study design on landscape genetics inference, we used a spatially-explicit, individual-based program to simulate gene flow in a spatially continuous population inhabiting a landscape with gradual spatial changes in resistance to movement. We simulated a wide range of combinations of number of loci, number of alleles per locus and number of individuals sampled from the population. We assessed how these three aspects of study design influenced the statistical power to successfully identify the generating process among competing hypotheses of isolation-by-distance, isolation-by-barrier, and isolation-by-landscape resistance using a causal modelling approach with partial Mantel tests. We modelled the statistical power to identify the generating process as a response surface for equilibrium and non-equilibrium conditions after introduction of isolation-by-landscape resistance. All three variables (loci, alleles and sampled individuals) affect the power of causal modelling, but to different degrees. Stronger partial Mantel r correlations between landscape distances and genetic distances were found when more loci were used and when loci were more variable, which makes comparisons of effect size between studies difficult. Number of individuals did not affect the accuracy through mean equilibrium partial Mantel r, but larger samples decreased the uncertainty (increasing the precision) of equilibrium partial Mantel r estimates. We conclude that amplifying more (and more variable) loci is likely to increase the power of landscape genetic inferences more than increasing number of individuals.

  10. Effects of sample size, number of markers, and allelic richness on the detection of spatial genetic pattern

    USGS Publications Warehouse

    Landguth, E.L.; Fedy, B.C.; Oyler-McCance, S.J.; Garey, A.L.; Emel, S.L.; Mumma, M.; Wagner, H.H.; Fortin, M.-J.; Cushman, S.A.

    2012-01-01

    The influence of study design on the ability to detect the effects of landscape pattern on gene flow is one of the most pressing methodological gaps in landscape genetic research. To investigate the effect of study design on landscape genetics inference, we used a spatially-explicit, individual-based program to simulate gene flow in a spatially continuous population inhabiting a landscape with gradual spatial changes in resistance to movement. We simulated a wide range of combinations of number of loci, number of alleles per locus and number of individuals sampled from the population. We assessed how these three aspects of study design influenced the statistical power to successfully identify the generating process among competing hypotheses of isolation-by-distance, isolation-by-barrier, and isolation-by-landscape resistance using a causal modelling approach with partial Mantel tests. We modelled the statistical power to identify the generating process as a response surface for equilibrium and non-equilibrium conditions after introduction of isolation-by-landscape resistance. All three variables (loci, alleles and sampled individuals) affect the power of causal modelling, but to different degrees. Stronger partial Mantel r correlations between landscape distances and genetic distances were found when more loci were used and when loci were more variable, which makes comparisons of effect size between studies difficult. Number of individuals did not affect the accuracy through mean equilibrium partial Mantel r, but larger samples decreased the uncertainty (increasing the precision) of equilibrium partial Mantel r estimates. We conclude that amplifying more (and more variable) loci is likely to increase the power of landscape genetic inferences more than increasing number of individuals. ?? 2011 Blackwell Publishing Ltd.

  11. In-beam gamma-ray spectroscopy of very neutron-rich nuclei: excited states in 46S and 48Ar.

    PubMed

    Gade, A; Adrich, P; Bazin, D; Brown, B A; Cook, J M; Diget, C Aa; Glasmacher, T; McDaniel, S; Ratkiewicz, A; Siwek, K; Weisshaar, D

    2009-05-08

    We report on the first in-beam gamma-ray spectroscopy study of the very neutron-rich nucleus 46S. The N=30 isotones 46S and 48Ar were produced in a novel way in two steps that both necessarily involve nucleon exchange and neutron pickup reactions 9Be(48Ca,48K)X followed by 9Be(48K,48Ar+gamma)X at 85.7 MeV/u midtarget energy and 9Be(48Ca,46Cl)X followed by 9Be(46Cl,46S+gamma)X at 87.0 MeV/u midtarget energy, respectively. The results are compared to large-scale shell-model calculations in the sd-pf shell using the SDPF-NR effective interaction and Z-dependent modifications.

  12. In-Beam {gamma}-Ray Spectroscopy of Very Neutron-Rich Nuclei: Excited States in {sup 46}S and {sup 48}Ar

    SciTech Connect

    Gade, A.; Brown, B. A.; Cook, J. M.; Glasmacher, T.; McDaniel, S.; Ratkiewicz, A.; Siwek, K.; Adrich, P.; Bazin, D.; Diget, C. A.; Weisshaar, D.

    2009-05-08

    We report on the first in-beam {gamma}-ray spectroscopy study of the very neutron-rich nucleus {sup 46}S. The N=30 isotones {sup 46}S and {sup 48}Ar were produced in a novel way in two steps that both necessarily involve nucleon exchange and neutron pickup reactions {sup 9}Be({sup 48}Ca,{sup 48}K)X followed by {sup 9}Be({sup 48}K,{sup 48}Ar+{gamma})X at 85.7 MeV/u midtarget energy and {sup 9}Be({sup 48}Ca,{sup 46}Cl)X followed by {sup 9}Be({sup 46}Cl,{sup 46}S+{gamma})X at 87.0 MeV/u midtarget energy, respectively. The results are compared to large-scale shell-model calculations in the sd-pf shell using the SDPF-NR effective interaction and Z-dependent modifications.

  13. The Laramide Caborca orogenic gold belt of northwestern Sonora, Mexico; white mica 40Ar/39Ar geochronology from gold-rich quartz veins

    USGS Publications Warehouse

    Izaguirre, Aldo; Kunk, Michael J.; Iriondo, Alexander; McAleer, Ryan; Caballero-Martinez, Juan Antonio; Espinosa-Arámburu, Enrique

    2016-02-12

    The COGB is approximately 600 kilometers long and 60 to 80 km wide, trends northwest, and extends from west-central Sonora to southern Arizona and California. The COGB contains mineralized gold-rich quartz veins that contain free gold associated with white mica (sericite), carbonate minerals (calcite and ankerite), and sulfides such as pyrite and galena. Limited geochronologic studies exist for parts of the COGB, and previous work was concentrated in mining districts. These previous studies recorded mineralization ages of approximately 70 to 40 Ma. Therefore, some workers proposed that the orogenic gold mineralization in the region occurred during a single pulse that was associated with the Laramide Orogeny that took place during the Cretaceous to early Eocene in the western margin of North America. However, the geochronologic dataset was quite limited, making any regional interpretations tenuous. Accordingly, one of the objectives of this geochronology study was to get a better representative sampling of the COGB in order to obtain a more complete record of the mineralization history. The 63 samples presented in this work are broadly distributed throughout the area of the COGB and allow us to better test the hypothesis that mineralization occurred in a single pulse.

  14. Effect of thermal maturation on the K-Ar, Rb-Sr and REE systematics of an organic-rich New Albany Shale as determined by hydrous pyrolysis

    USGS Publications Warehouse

    Clauer, Norbert; Chaudhuri, Sambhudas; Lewan, M.D.; Toulkeridis, T.

    2006-01-01

    Hydrous-pyrolysis experiments were conducted on an organic-rich Devonian-Mississippian shale, which was also leached by dilute HCl before and after pyrolysis, to identify and quantify the induced chemical and isotopic changes in the rock. The experiments significantly affect the organic-mineral organization, which plays an important role in natural interactions during diagenetic hydrocarbon maturation in source rocks. They produce 10.5% of volatiles and the amount of HCl leachables almost doubles from about 6% to 11%. The Rb-Sr and K-Ar data are significantly modified, but not just by removal of radiogenic 40Ar and 87Sr, as described in many studies of natural samples at similar thermal and hydrous conditions. The determining reactions relate to alteration of the organic matter marked by a significant change in the heavy REEs in the HCl leachate after pyrolysis, underlining the potential effects of acidic fluids in natural environments. Pyrolysis induces also release from organics of some Sr with a very low 87Sr/86Sr ratio, as well as part of U. Both seem to have been volatilised during the experiment, whereas other metals such as Pb, Th and part of U appear to have been transferred from soluble phases into stable (silicate?) components. Increase of the K2O and radiogenic 40Ar contents of the silicate minerals after pyrolysis is explained by removal of other elements that could only be volatilised, as the system remains strictly closed during the experiment. The observed increase in radiogenic 40Ar implies that it was not preferentially released as a volatile gas phase when escaping the altered mineral phases. It had to be re-incorporated into newly-formed soluble phases, which is opposite to the general knowledge about the behavior of Ar in supergene natural environments. Because of the strictly closed-system conditions, hydrous-pyrolysis experiments allow to better identify and even quantify the geochemical aspects of organic-inorganic interactions, such as

  15. Homozygous carriers of the TCF7L2 rs7903146 T-allele show altered postprandial response in triglycerides and triglyceride-rich lipoproteins

    PubMed Central

    Engelbrechtsen, L.; Hansen, T. H.; Mahendran, Y.; Pyl, P.; Andersson, E.; Jonsson, A.; Gjesing, A.; Linneberg, A.; Jørgensen, T.; Hansen, T.; Vestergaard, H.

    2017-01-01

    The TCF7L2 rs7903146 T-allele shows the strongest association with type 2 diabetes (T2D) among common gene variants. The aim of this study was to assess circulating levels of metabolites following a meal test in individuals carrying the high risk rs790346 TT genotype (cases) and low-risk CC genotype (controls). Sixty-two men were recruited based on TCF7L2 genotype, 31 were TT carriers and 31 were age- and BMI-matched CC carriers. All participants consumed a test meal after 12 hours of fasting. Metabolites were measured using proton nuclear magnetic resonance (NMR) spectroscopy. Metabolomic profiling of TCF7L2 carriers were performed for 141 lipid estimates. TT carriers had lower fasting levels of L-VLDL-L (total lipids in large very low density lipoproteins, p = 0.045), L-VLDL-CE (cholesterol esters in large VLDL, p = 0.03), and L-VLDL-C (total cholesterol in large VLDL, p = 0.045) compared to CC carriers. Additionally, TT carriers had lower postprandial levels of total triglycerides (TG) (q = 0.03), VLDL-TG (q = 0.05, including medium, small and extra small, q = 0.048, q = 0.0009, q = 0.04, respectively), HDL-TG (triglycerides in high density lipoproteins q = 0.037) and S-HDL-TG (q = 0.00003). In conclusion, TT carriers show altered postprandial triglyceride response, mainly influencing VLDL and HDL subclasses suggesting a genotype-mediated effect on hepatic lipid regulation. PMID:28220878

  16. The phenome analysis of mutant alleles in Leucine-Rich Repeat Receptor-Like Kinase genes in rice reveals new potential targets for stress tolerant cereals.

    PubMed

    Dievart, Anne; Perin, Christophe; Hirsch, Judith; Bettembourg, Mathilde; Lanau, Nadège; Artus, Florence; Bureau, Charlotte; Noel, Nicolas; Droc, Gaétan; Peyramard, Matthieu; Pereira, Serge; Courtois, Brigitte; Morel, Jean-Benoit; Guiderdoni, Emmanuel

    2016-01-01

    Plants are constantly exposed to a variety of biotic and abiotic stresses that reduce their fitness and performance. At the molecular level, the perception of extracellular stimuli and the subsequent activation of defense responses require a complex interplay of signaling cascades, in which protein phosphorylation plays a central role. Several studies have shown that some members of the Leucine-Rich Repeat Receptor-Like Kinase (LRR-RLK) family are involved in stress and developmental pathways. We report here a systematic analysis of the role of the members of this gene family by mutant phenotyping in the monocotyledon model plant rice, Oryza sativa. We have then targeted 176 of the ∼320 LRR-RLK genes (55.7%) and genotyped 288 mutant lines. Position of the insertion was confirmed in 128 lines corresponding to 100 LRR-RLK genes (31.6% of the entire family). All mutant lines harboring homozygous insertions have been screened for phenotypes under normal conditions and under various abiotic stresses. Mutant plants have been observed at several stages of growth, from seedlings in Petri dishes to flowering and grain filling under greenhouse conditions. Our results show that 37 of the LRR-RLK rice genes are potential targets for improvement especially in the generation of abiotic stress tolerant cereals.

  17. Primordial abundance of 40Ar

    NASA Astrophysics Data System (ADS)

    Sripada, V. S. Murty

    Primordial abundance of the isotope (40) Ar is still not known accurately. Recent results from Genesis could also not provide (40) Ar/ (36) Ar value of solar wind, due mainly to the overwhelming (40) Ar blank. A major part of (40) Ar is contributed by the radioactive decay of (40) K (half life = 1.25 Ga), even in the nebula, as the nebula grew old. Any attempt to determine this quantity needs a sample that satisfies the following criteria: A primitive mineral/phase that formed very early in the nebula, that can trap a large amount of noble gas (Ar); and a phase that acquires minimum amount (or total absence) of in situ produced components (cosmogenic and radiogenic) of Ar. Carbon phases in the ureilite meteorites and Phase Q from chondrites best fit this criteria. The minimum (40) Ar/ (36) Ar value so far observed in Phase Q is 0.2. Also, the relatively lower value of 1.035±±0.002 for trapped (129) Xe/ (132) Xe in ureilites, as compared to 1.042±±0.002 in Phase Q suggests that trapping of gases in ureilites might have predated that of Phase Q. If this interpretation is valid, ureilites are a better host of most primitive nebular Ar. Earlier attempts on ureilite studies in 1970s have yielded the lowest (40) Ar/ (36) Ar ratio in the meteorite Dayalpur, the major uncertainty for this value mostly coming from blank correction for (40) Ar/ (36) Ar. Recent developments in low blank extraction systems and more sensitive multi-collector noble gas mass spectrometers, as compared to 1970s have prompted us to make a fresh attempt in measuring this important quantity. We have analysed a number of ureilite acid residues by stepwise temperature extraction, using both pyrolysis and combustion techniques, for Ar to ascertain the trapped (40) Ar/ (36) Ar ratio in the solar nebula. These acid residues are mostly made of C rich phases, with only trace amounts of K (radiogenic parent of (40) Ar) and target elements for the production of cosmogenic Ar component. They mostly contain

  18. Two-cell detonation: losses effects on cellular structure and propagation in rich H2-NO2/N2O4-Ar mixtures

    NASA Astrophysics Data System (ADS)

    Virot, F.; Khasainov, B.; Desbordes, D.; Presles, H.-N.

    2010-12-01

    Detonation experiments in H2-NO2/N2O4-Ar mixtures (Equivalence ratio 1.2 and initial pressure lower than 0.1 MPa) confined in a tube of internal diameter 52 mm reveal two propagation regimes depending on initial pressure: (1) a quasi-CJ regime is observed along with a double cellular structure at high pressures; (2) at lower pressures, a low velocity detonation regime is observed with a single structure. Transition between this two regimes happens when the spinning detonation of the larger cell vanishes. Each detonation regime is characterized by velocity and pressure measurements and cellular structure records. Coherence between all experimental data for each experiment leads in assumption that losses are responsible for the transition between one regime to another. In a second part, we study such behaviour for a two-step mixture through numerical simulations using a global two-step chemical kinetics and a simple losses model. Numerical simulations qualitatively agree with experiments. Both detonation regimes with their own cellular structures are reproduced.

  19. Vibrational spectroscopy study of Ar+-ion irradiated Si-rich oxide films grown by plasma-enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Mariotto, G.; Das, G.; Quaranta, A.; Della Mea, G.; Corni, F.; Tonini, R.

    2005-06-01

    SiOx thin films with different stoichiometry degree were obtained by plasma-enhanced chemical vapor deposition on crystalline silicon substrates from SiH4 and N2O gas mixtures. Two twin sets of samples were irradiated by 380 keV Ar+ ions at a fluence of 5×1016ions/cm2 at room temperature and at 500 °C, respectively, and then annealed in vacuum at different temperatures, between 500 and 1100 °C. A set of unirradiated samples has been annealed in the same conditions in order to discriminate the contribution of ion irradiation and of thermal treatments to the changes of the film microstructure. The structural modification of the oxide network and the growth of Si nanoclusters have been studied by vibrational spectroscopy techniques. Fourier transform infrared absorption spectra evidenced that ion irradiation induces a hydrogen loss of about 50%, and that postirradiation thermal treatments lead to the recovery of the irradiation defects and to the out diffusion of the residual hydrogen. After heating at 800 °C, irradiated and unirradiated samples exhibit substantially the same structure from the point of view of infrared-absorption spectra. In the meanwhile, the Si-O-Si stretching peak blue shifts, but never reaches the wavenumber value of pure silica owing to the presence of nitrogen into the network. Raman spectra of as-irradiated films reveal the presence of an amorphous silicon phase within the damaged layer of the oxide matrix. Raman spectra of irradiated samples undergoing thermal treatments at high temperature indicate a rearrangement of the film microstructure with the progressive clustering of the amorphous silicon phase. However, no clear spectroscopic evidence is gained about the crystallization of silicon nanoclusters, even after annealing at the highest temperature. In fact, the Raman scattering from silicon nanocrystals is partially hidden by the Raman peak of the c-Si substrate.

  20. Ar-39/Ar-40 systematics of Allende inclusions

    NASA Technical Reports Server (NTRS)

    Herzog, G. F.; Bence, A. E.; Bender, J.; Eichhorn, G.; Maluski, H.; Schaeffer, O. A.

    1980-01-01

    A laser microprobe was used to measure the Ar isotopic contents of individual mineral grains in four neutron-irradiated Allende samples: two coarse-grained Ca-Al-rich inclusions; one fine-grained Ca-Al-rich inclusion; and one sample with matrix and miscellaneous chondrules. The following K-Ar ages (G.y.) were obtained after degassing low Ar retentive sites by preheating the samples for one hour at 675 C: matrix, 3.5 + or - 0.2; three miscellaneous chondrules, 4.4 + or - 0.1, 4.0 + or - 0.1, and 4.4 + or - 0.1; and the fine-grained inclusion, 4.5 + or - 0.2. The minerals in the coarse-grained Ca-Al-rich inclusions have ubiquitous chlorine, less than 10 ppm K and apparent ages ranging upwards from 4.6 G.y. to well over 10 G.y. Possible explanations for these apparent ages are atmospheric contamination, the decay of K-40 prior to the formation of the solar system, and the trapping of radiogenic Ar-40 lost by the matrix.

  1. Topography evolution of 500 keV Ar(4+) ion beam irradiated InP(100) surfaces - formation of self-organized In-rich nano-dots and scaling laws.

    PubMed

    Sulania, Indra; Agarwal, Dinesh C; Kumar, Manish; Kumar, Sunil; Kumar, Pravin

    2016-07-27

    We report the formation of self-organized nano-dots on the surface of InP(100) upon irradiating it with a 500 keV Ar(4+) ion beam. The irradiation was carried out at an angle of 25° with respect to the normal at the surface with 5 different fluences ranging from 1.0 × 10(15) to 1.0 × 10(17) ions per cm(2). The morphology of the ion-irradiated surfaces was examined by atomic force microscopy (AFM) and the formation of the nano-dots on the irradiated surfaces was confirmed. The average size of the nano-dots varied from 44 ± 14 nm to 94 ± 26 nm with increasing ion fluence. As a function of the ion fluence, the variation in the average size of the nano-dots has a great correlation with the surface roughness, which changes drastically up to the ion fluence of 1.0 × 10(16) ions per cm(2) and attains almost a saturation level for further irradiation. The roughness and the growth exponent values deduced from the scaling laws suggest that the kinetic sputtering and the large surface diffusion steps of the atoms are the primary reasons for the formation of the self-organized nanodots on the surface. X-ray photo-electron spectroscopy (XPS) studies show that the surface stoichiometry changes with the ion fluence. With irradiation, the surface becomes more indium (In)-rich owing to the preferential sputtering of the phosphorus atoms (P) and the pure metallic In nano-dots evolve at the highest ion fluence. The cross-sectional scanning electron microscopy (SEM) analysis of the sample irradiated with the highest fluence showed the absence of the nanostructuring beneath the surface. The surface morphological changes at this medium energy ion irradiation are discussed in correlation with the low and high energy experiments to shed more light on the mechanism of the well separated nano-dot formation.

  2. Ar-Ar_Redux: rigorous error propagation of 40Ar/39Ar data, including covariances

    NASA Astrophysics Data System (ADS)

    Vermeesch, P.

    2015-12-01

    Rigorous data reduction and error propagation algorithms are needed to realise Earthtime's objective to improve the interlaboratory accuracy of 40Ar/39Ar dating to better than 1% and thereby facilitate the comparison and combination of the K-Ar and U-Pb chronometers. Ar-Ar_Redux is a new data reduction protocol and software program for 40Ar/39Ar geochronology which takes into account two previously underappreciated aspects of the method: 1. 40Ar/39Ar measurements are compositional dataIn its simplest form, the 40Ar/39Ar age equation can be written as: t = log(1+J [40Ar/39Ar-298.5636Ar/39Ar])/λ = log(1 + JR)/λ Where λ is the 40K decay constant and J is the irradiation parameter. The age t does not depend on the absolute abundances of the three argon isotopes but only on their relative ratios. Thus, the 36Ar, 39Ar and 40Ar abundances can be normalised to unity and plotted on a ternary diagram or 'simplex'. Argon isotopic data are therefore subject to the peculiar mathematics of 'compositional data', sensu Aitchison (1986, The Statistical Analysis of Compositional Data, Chapman & Hall). 2. Correlated errors are pervasive throughout the 40Ar/39Ar methodCurrent data reduction protocols for 40Ar/39Ar geochronology propagate the age uncertainty as follows: σ2(t) = [J2 σ2(R) + R2 σ2(J)] / [λ2 (1 + R J)], which implies zero covariance between R and J. In reality, however, significant error correlations are found in every step of the 40Ar/39Ar data acquisition and processing, in both single and multi collector instruments, during blank, interference and decay corrections, age calculation etc. Ar-Ar_Redux revisits every aspect of the 40Ar/39Ar method by casting the raw mass spectrometer data into a contingency table of logratios, which automatically keeps track of all covariances in a compositional context. Application of the method to real data reveals strong correlations (r2 of up to 0.9) between age measurements within a single irradiation batch. Propertly taking

  3. Ar-40/Ar-39 laser-probe dating of diamond inclusions from the Premier kimberlite

    NASA Technical Reports Server (NTRS)

    Phillips, D.; Onstott, T. C.; Harris, J. W.

    1989-01-01

    The results of Ar-40/Ar-39 laser-probe analyses of individual eclogitic clinopyroxene inclusions from Premier diamonds are reported which yield a mean age of 1198 + or - 14 Myr. This age agrees well with Sm-Nd and Ar-40/Ar-39 analyses on similar Premier inclusions and is indistinguishable from the inferred time of emplacement of the host kimberlite, which implies that diamond formation was essentially synchronous with kimberlite generation. The extrapolated nonradiogenic Ar-40/Ar-36 ratio of 334 + or - 102 is similar to the present-day atmospheric composition. This value is inconsistent with Sr and Nd isotopic signatures from Premier eclogite inclusions, which suggest a depleted mantle source. Preentrapment equilibration of the inclusions with an Ar-36-rich fluid is the most probable explanation for the low nonradiogenic composition.

  4. ArArCALC—software for 40Ar/ 39Ar age calculations

    NASA Astrophysics Data System (ADS)

    Koppers, Anthony A. P.

    2002-06-01

    ArArCALC is a Microsoft Excel ® 97-2000-XP application for performing calculations in 40Ar/ 39Ar geochronology. It is coded in Visual Basic for Applications and can be used under the Windows ® 95/98/NT/2000/ME/XP operating systems. ArArCALC provides an easy-to-use graphical interface for the calculation of age plateaus, total fusion ages and isochrons following the regression of 40Ar/ 39Ar mass spectrometry data. Results are stored in single Excel workbooks including nine different data tables and four different diagrams. Analytical, internal and external errors are calculated based on error propagation of all input parameters, analytical data and applied corrections. Finally, the age calculation results can be recalibrated with reference to the primary K-Ar standards (e.g. GA-1550, MMhb-1) in order to obtain more consistent absolute40Ar/ 39Ar age determinations. ArArCALC is distributed as freeware.

  5. Construction of a chimeric ArsA-ArsB protein for overexpression of the oxyanion-translocating ATPase.

    PubMed

    Dou, D; Owolabi, J B; Dey, S; Rosen, B P

    1992-12-25

    Resistance to toxic oxyanions of arsenic and antimony in Escherichia coli is conferred by the conjugative R-factor R773, which encodes an ATP-driven anion extrusion pump. The ars operon is composed of three structural genes, arsA, arsB, and arsC. Although transcribed as a single unit, the three genes are differentially expressed as a result of translational differences, such that the ArsA and ArsC proteins are produced in high amounts relative to the amount of ArsB protein made. Consequently, biochemical characterization of the ArsB protein, which is an integral membrane protein containing the anion-conducting pathway, has been limited, precluding studies of the mechanism of this oxyanion pump. To overexpress the arsB gene, a series of changes were made. First, the second codon, an infrequently used leucine codon, was changed to a more frequently utilized codon. Second, a GC-rich stem-loop (delta G = -17 kcal/mol) between the third and twelfth codons was destabilized by changing several of the bases of the base-paired region. Third, the re-engineered arsB gene was fused 3' in frame to the first 1458 base pairs of the arsA gene to encode a 914-residue chimeric protein (486 residues of the ArsA protein plus 428 residues of the mutated ArsB protein) containing the entire re-engineered ArsB sequence except for the initiating methionine. The ArsA-ArsB chimera has been overexpressed at approximately 15-20% of the total membrane proteins. Cells producing the chimeric ArsA-ArsB protein with an arsA gene in trans excluded 73AsO2- from cells, demonstrating that the chimera can function as a component of the oxyanion-translocating ATPase.

  6. Intragenic allele pyramiding combines different specificities of wheat Pm3 resistance alleles.

    PubMed

    Brunner, Susanne; Hurni, Severine; Streckeisen, Philipp; Mayr, Gabriele; Albrecht, Mario; Yahiaoui, Nabila; Keller, Beat

    2010-11-01

    Some plant resistance genes occur as allelic series, with each member conferring specific resistance against a subset of pathogen races. In wheat, there are 17 alleles of the Pm3 gene. They encode nucleotide-binding (NB-ARC) and leucine-rich-repeat (LRR) domain proteins, which mediate resistance to distinct race spectra of powdery mildew. It is not known if specificities from different alleles can be combined to create resistance genes with broader specificity. Here, we used an approach based on avirulence analysis of pathogen populations to characterize the molecular basis of Pm3 recognition spectra. A large survey of mildew races for avirulence on the Pm3 alleles revealed that Pm3a has a resistance spectrum that completely contains that of Pm3f, but also extends towards additional races. The same is true for the Pm3b and Pm3c gene pair. The molecular analysis of these allelic pairs revealed a role of the NB-ARC protein domain in the efficiency of effector-dependent resistance. Analysis of the wild-type and chimeric Pm3 alleles identified single residues in the C-terminal LRR motifs as the main determinant of allele specificity. Variable residues of the N-terminal LRRs are necessary, but not sufficient, to confer resistance specificity. Based on these data, we constructed a chimeric Pm3 gene by intragenic allele pyramiding of Pm3d and Pm3e that showed the combined resistance specificity and, thus, a broader recognition spectrum compared with the parental alleles. Our findings support a model of stepwise evolution of Pm3 recognition specificities.

  7. MAIZE ALLELIC DIVERSITY PROJECT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Of the estimated 250-300 races of maize, only 24 races are represented in materials utilized by the Germplasm Enhancement of Maize (GEM) project, a collaborative effort between USDA-ARS and public and private sector research scientists. This is largely a result of poor performance of many races in ...

  8. 40Ar/39Ar systematics and argon diffusion in amber: implications for ancient earth atmospheres

    USGS Publications Warehouse

    Landis, G.P.; Snee, L.W.

    1991-01-01

    Argon isotope data indicate retained argon in bulk amber (matrix gas) is radiogenic [40Ar/39Ar ???32o] than the much more abundant surface absorbed argon [40Ar/39Ar ???295.5]. Neutron-induced 39Ar is retained in amber during heating experiments to 150?? -250??C, with no evidence of recoiled 39Ar found after irradiation. A maximum permissible volume diffusion coefficient of argon in amber (at ambient temperature) D???1.5 x 10-17 cm2S-1 is calculated from 39Ar retention. 40Ar/39Ar age calculations indicate Dominican Republic amber is ??? 45 Ma and North Dakota amber is ??? 89 Ma, both at least reasonable ages for the amber based upon stratigraphic and paleontological constraints and upon the small amount of radiogenic 40Ar. To date, over 300 gas analyses of ambers and resins of Cretaceous to Recent age that are geographically distributed among fifteen noted world locations identify mixtures of gases in different sites within amber (Berner and Landis, 1988). The presence of multiple mixing trends between compositionally distinct end-members gases within the same sample and evidence for retained radiogenic argon within the amber argue persuasivley against rapid exchange by diffusion of amber-contained gases with moder air. Only gas in primary bubbles entrapped between successive flows of tree resin has been interpreted as original "ancient air", which is an O2-rich end-member gas with air-like N2/Ar ratios. Gas analyses of these primary bubbles indicate atmospheric O2 levels in the Late Cretaceous of ??? 35%, and that atmospheric O2 dropped by early Tertiary time to near a present atmospheric level of 21% O2. A very low argon diffusion coefficient in amber persuasively argues for a gas in primary bubbles trapped in amber being ancient air (possibly modified only by O2 reaction with amber). ?? 1991.

  9. Plasma AR and abiraterone-resistant prostate cancer.

    PubMed

    Romanel, Alessandro; Gasi Tandefelt, Delila; Conteduca, Vincenza; Jayaram, Anuradha; Casiraghi, Nicola; Wetterskog, Daniel; Salvi, Samanta; Amadori, Dino; Zafeiriou, Zafeiris; Rescigno, Pasquale; Bianchini, Diletta; Gurioli, Giorgia; Casadio, Valentina; Carreira, Suzanne; Goodall, Jane; Wingate, Anna; Ferraldeschi, Roberta; Tunariu, Nina; Flohr, Penny; De Giorgi, Ugo; de Bono, Johann S; Demichelis, Francesca; Attard, Gerhardt

    2015-11-04

    Androgen receptor (AR) gene aberrations are rare in prostate cancer before primary hormone treatment but emerge with castration resistance. To determine AR gene status using a minimally invasive assay that could have broad clinical utility, we developed a targeted next-generation sequencing approach amenable to plasma DNA, covering all AR coding bases and genomic regions that are highly informative in prostate cancer. We sequenced 274 plasma samples from 97 castration-resistant prostate cancer patients treated with abiraterone at two institutions. We controlled for normal DNA in patients' circulation and detected a sufficiently high tumor DNA fraction to quantify AR copy number state in 217 samples (80 patients). Detection of AR copy number gain and point mutations in plasma were inversely correlated, supported further by the enrichment of nonsynonymous versus synonymous mutations in AR copy number normal as opposed to AR gain samples. Whereas AR copy number was unchanged from before treatment to progression and no mutant AR alleles showed signal for acquired gain, we observed emergence of T878A or L702H AR amino acid changes in 13% of tumors at progression on abiraterone. Patients with AR gain or T878A or L702H before abiraterone (45%) were 4.9 and 7.8 times less likely to have a ≥50 or ≥90% decline in prostate-specific antigen (PSA), respectively, and had a significantly worse overall [hazard ratio (HR), 7.33; 95% confidence interval (CI), 3.51 to 15.34; P = 1.3 × 10(-9)) and progression-free (HR, 3.73; 95% CI, 2.17 to 6.41; P = 5.6 × 10(-7)) survival. Evaluation of plasma AR by next-generation sequencing could identify cancers with primary resistance to abiraterone.

  10. Towards establishing high-precision 40Ar/39Ar chronologies for distal tephra archives

    NASA Astrophysics Data System (ADS)

    Mark, D. F.

    2012-12-01

    39Ar recoil effects. These effects are amplified by a high surface area to volume ratio of glass shards and thus short effective diffusion dimensions (radii of glass shards). I will discuss the application of 40Ar/39Ar geochronology to distal tephra and present two methodologies for establishing absolute 40Ar/39Ar age constraints for distal tephra archives. Two case studies will be presented: [1] dating of distal tephra in Lake Suigetsu, Japan by establishing robust correlations between proximal (crystal-rich) and distal (crystal-poor) volcanic deposits, and [2] dating of distal Toba tephra throughout peninsular of India by targeting of sub-100 μm shards of biotite. A look at future development in 40Ar/39Ar geochronology and noble gas mass spectrometry with implications for tephrochronology studies will conclude the presentation.

  11. Neutron-Proton Asymmetry Dependence of Spectroscopic Factors in Ar Isotopes

    SciTech Connect

    Lee, Jenny; Tsang, Betty; Shapira, Dan

    2010-01-01

    Spectroscopic factors have been extracted for proton-rich 34Ar and neutron-rich 46Ar using the (p, d) neutron transfer reaction. The experimental results show little reduction of the ground state neutron spectroscopic factor of the proton-rich nucleus 34Ar compared to that of 46Ar. The results suggest that correlations, which generally reduce such spectroscopic factors, do not depend strongly on the neutron-proton asymmetry of the nucleus in this isotopic region as was reported in knockout reactions. The present results are consistent with results from systematic studies of transfer reactions but inconsistent with the trends observed in knockout reaction measurements.

  12. AR Alternative Splicing and Prostate Cancer Progression

    DTIC Science & Technology

    2012-07-01

    the PCR target regions . For conventional PCR, genomic DNA was amplified using a Taq Polymerase PCR kit (Qia- gen), according to the manufacturer’s...n repeats and AT-rich sequence in both of these regions (Fig. 4C). It is common for the endpoints of genomic deletions or insertions to map to...rearrangements under- lying TE- related genetic diseases, including cancer (29), and often arise through NAHR. However, sequencing the 22Rv1 AR break fusion

  13. 39Ar- 40Ar ages of martian nakhlites

    NASA Astrophysics Data System (ADS)

    Park, Jisun; Garrison, Daniel H.; Bogard, Donald D.

    2009-04-01

    We report 39Ar- 40Ar ages of whole rock (WR) and plagioclase and pyroxene mineral separates of nakhlites MIL 03346 and Y-000593, and of WR samples of nakhlites NWA 998 and Nakhla. All age spectra are complex and indicate variable degrees of 39Ar recoil and variable amounts of trapped 40Ar in the samples. Thus, we examine possible Ar-Ar ages in several ways. From consideration of both limited plateau ages and isochron ages, we prefer Ar-Ar ages of NWA 998 = 1334 ± 11 Ma, MIL 03346 = 1368 ± 83 Ma (mesostasis) and 1334 ± 54 Ma (pyroxene), Y-000593 = 1367 ± 7 Ma, and Nakhla = 1357 ± 11 Ma, (2 σ errors). For NWA 998 and MIL 03346 the Ar-Ar ages are within uncertainties of preliminary Rb-Sr isochron ages reported in the literature. These Ar-Ar ages for Y-000593 and Nakhla are several Ma older than Sm-Nd ages reported in the literature. We conclude that the major factor in producing Ar-Ar ages slightly too old is the presence of small amounts of trapped martian or terrestrial 40Ar on weathered grain surfaces that was degassed along with the first several percent of 39Ar. A total K- 40Ar isochron for WR and mineral data from five nakhlites analyzed by us, plus Lafayette data in the literature, gives an isochron age of 1325 ± 18 Ma (2 σ). We emphasize the precision of this isochron over the value of the isochron age. Our Ar-Ar data are consistent with a common formation age for nakhlites. The cosmic-ray exposure (CRE) age for NWA 998 of ˜12 Ma is also similar to CRE ages for other nakhlites.

  14. Multinucleon transfer reactions in the 40Ar+208Pb system

    NASA Astrophysics Data System (ADS)

    Mijatović, T.; Szilner, S.; Corradi, L.; Montanari, D.; Pollarolo, G.; Fioretto, E.; Gadea, A.; Goasduff, A.; Malenica, D. Jelavić; Mǎrginean, N.; Milin, M.; Montagnoli, G.; Scarlassara, F.; Soić, N.; Stefanini, A. M.; Ur, C. A.; Valiente-Dobón, J. J.

    2016-12-01

    We measured multinucleon transfer reactions in the 40Ar+208Pb system at an energy close to the Coulomb barrier, by employing the PRISMA magnetic spectrometer. We extracted differential and total cross sections of the different transfer channels, with a careful investigation of the total kinetic energy loss distributions. Comparisons between different systems having the same 208Pb target and with projectiles going from neutron-poor to neutron-rich nuclei, i.e., 40Ca, 58Ni, and 40Ar, as well as between the data and GRAZING calculations have been carried out. The neutron-rich (stable) 40Ar beam allowed us to get access to the channels involving proton pickup, whose behavior in connection with the production of neutron-rich heavy partner has been outlined.

  15. Maize ARGOS1 (ZAR1) transgenic alleles increase hybrid maize yield.

    PubMed

    Guo, Mei; Rupe, Mary A; Wei, Jun; Winkler, Chris; Goncalves-Butruille, Marymar; Weers, Ben P; Cerwick, Sharon F; Dieter, Jo Ann; Duncan, Keith E; Howard, Richard J; Hou, Zhenglin; Löffler, Carlos M; Cooper, Mark; Simmons, Carl R

    2014-01-01

    Crop improvement for yield and drought tolerance is challenging due to the complex genetic nature of these traits and environmental dependencies. This study reports that transgenic over-expression of Zea mays AR GOS1 (ZAR1) enhanced maize organ growth, grain yield, and drought-stress tolerance. The ZAR1 transgene exhibited environmental interactions, with yield increase under Temperate Dry and yield reduction under Temperate Humid or High Latitude environments. Native ZAR1 allele variation associated with drought-stress tolerance. Two founder alleles identified in the mid-maturity germplasm of North America now predominate in Pioneer's modern breeding programme, and have distinct proteins, promoters and expression patterns. These two major alleles show heterotic group partitioning, with one predominant in Pioneer's female and the other in the male heterotic groups, respectively. These two alleles also associate with favourable crop performance when heterozygous. Allele-specific transgene testing showed that, of the two alleles discussed here, each allele differed in their impact on yield and environmental interactions. Moreover, when transgenically stacked together the allelic pair showed yield and environmental performance advantages over either single allele, resembling heterosis effects. This work demonstrates differences in transgenic efficacy of native alleles and the differences reflect their association with hybrid breeding performance.

  16. An alternative hypothesis for high-T 40Ar/39Ar age spectrum discordance in polyphase extraterrestrial materials

    NASA Astrophysics Data System (ADS)

    Cassata, W. S.; Shuster, D. L.; Renne, P. R.; Weiss, B. P.

    2009-12-01

    A common feature observed in 40Ar/39Ar age spectra of extraterrestrial (ET) rocks is a conspicuous decrease in the ages of high temperature extractions relative to lower temperature steps and a correlated increase in Ca/K, often succeeded by a monotonic increase in ages. This feature is routinely attributed to recoil-implanted 39Ar from a potassium (K)-rich donor phase into a K-poor receptor phase (e.g., 1,2). While 39Ar recoil redistribution is undoubtedly manifested in many terrestrial and ET 40Ar/39Ar whole-rock age spectra, it cannot easily explain the magnitude of high release temperature 40Ar*/39ArK anomalies observed in Martian meteorites ALH 84001 and Nakhla, as well as other course-grained meteorites and lunar rocks. Depending on the aliquot and sample, 50 - 100% of the pyroxene release spectra in ALH 84001 and Nakhla appear strongly perturbed to lower ages. As the mean recoil distance of 39Ar ~0.1 µm, the recoil hypothesis demands that a high-K phase be ubiquitously distributed amongst sub-micron to micron sized pyroxene crystals to account for the observed pyroxene age spectra. However, in both Nakhla and ALH 84001, pyroxene is often completely isolated from high-K phases and individual grains commonly exceed 100 µm in diameter. 40Ar/39Ar analyses of pyroxene-bearing terrestrial basalts, wherein fine-grained pyroxene and plagioclase are intimately adjoined, show that recoil-implanted 39Ar into pyroxene produces much less precipitous anomalies in 40Ar*/39ArK, as predicted by the recoil lengthscale. An alternative hypothesis is that whole-rock age spectra of ET samples with anomalously low ages at high temperatures may reflect diffusive 40Ar distributions within considerably degassed pyroxene grains. Owing to apparent differences in activation energies between glass and/or plagioclase and pyroxene, 40Ar may diffuse more rapidly from pyroxene under certain high-temperature conditions (i.e., above the temperature at which the extrapolated Ar Arrhenius

  17. Earth-atmosphere evolution based on new determination of Devonian atmosphere Ar isotopic composition

    NASA Astrophysics Data System (ADS)

    Stuart, Finlay M.; Mark, Darren F.; Gandanger, Pierre; McConville, Paul

    2016-07-01

    The isotopic composition of the noble gases, in particular Ar, in samples of ancient atmosphere trapped in rocks and minerals provides the strongest constraints on the timing and rate of Earth atmosphere formation by degassing of the Earth's interior. We have re-measured the isotopic composition of argon in the Rhynie chert from northeast Scotland using a high precision mass spectrometer in an effort to provide constraints on the composition of Devonian atmosphere. Irradiated chert samples yield 40Ar/36Ar ratios that are often below the modern atmosphere value. The data define a 40Ar/36Ar value of 289.5 ± 0.4 at K/36Ar = 0. Similarly low 40Ar/36Ar are measured in un-irradiated chert samples. The simplest explanation for the low 40Ar/36Ar is the preservation of Devonian atmosphere-derived Ar in the chert, with the intercept value in 40Ar-39Ar-36Ar space representing an upper limit. In this case the Earth's atmosphere has accumulated only 3% (5.1 ± 0.4 ×1016 mol) of the total 40Ar inventory since the Devonian. The average accumulation rate of 1.27 ± 0.09 ×108 mol40Ar/yr overlaps the rate over the last 800 kyr. This implies that there has been no resolvable temporal change in the outgassing rate of the Earth since the mid-Palaeozoic despite the likely episodicity of Ar degassing from the continental crust. Incorporating the new Devonian atmosphere 40Ar/36Ar into the Earth degassing model of Pujol et al. (2013) provides the most precise constraints on atmosphere formation so far. The atmosphere formed in the first ∼100 Ma after initial accretion during a catastrophic degassing episode. A significant volume of 40Ar did not start to accumulate in the atmosphere until after 4 Ga which implies that stable K-rich continental crust did not develop until this time.

  18. Structure of the N=27 isotones derived from the {sup 44}Ar(d,p){sup 45}Ar reaction

    SciTech Connect

    Gaudefroy, L.; Beaumel, D.; Blumenfeld, Y.; Fortier, S.; Franchoo, S.; Hammache, F.; Roussel, P.; Stanoiu, M.; Tryggestad, E.; Dombradi, Z.; Sohler, D.; Grevy, S.; St Laurent, M. G.; Roussel-Chomaz, P.; Kratz, K. L.; Lukyanov, S. M.; Penionzhkevich, Yu.-E.

    2008-09-15

    The {sup 44}Ar(d,p){sup 45}Ar neutron transfer reaction was performed at 10A MeV. Measured excitation energies, deduced angular momenta, and spectroscopic factors of the states populated in {sup 45}Ar are reported. A satisfactory description of these properties is achieved in the shell model framework using a new sdpf interaction. The model analysis is extended to more exotic even-Z nuclei down to {sub 14}{sup 41}Si{sub 27} to study how collectivity impacts the low-lying structure of N=27 neutron-rich nuclei.

  19. Ar/Ar Dating Independent of Monitor Standard Ages

    NASA Astrophysics Data System (ADS)

    Boswell, S.; Hemming, S. R.

    2015-12-01

    Because the reported age of an analyzed sample is dependent on the age of the co-irradiated monitor standard(s), Ar/Ar dating is a relative dating technique. There is disagreement at the 1% scale in the age of commonly used monitor standards, and there is a great need to improve the inter-laboratory calibrations. Additionally, new approaches and insights are needed to meet the challenge of bringing the Ar/Ar chronometer to the highest possible precision and accuracy. In this spirit, we present a conceptual framework for Ar/Ar dating that does not depend on the age of monitor standards, but only on the K content of a solid standard. The concept is demonstrated by introducing a re-expressed irradiation parameter (JK) that depends on the ratio of 39ArK to 40Ar* rather than the 40Ar*/39ArK ratio. JK is equivalent to the traditional irradiation parameter J and is defined as JK = (39Ar/40K) • (λ/λe). The ultimate precision and accuracy of the method will depend on how precisely and accurately the 39Ar and 40K can be estimated, and will require isotope dilution measurements of both from the same aliquot. We are testing the workability of our technique at the 1% level by measuring weighed and irradiated hornblende and biotite monitor standards using GLO-1 glauconite to define a calibration curve for argon signals versus abundance.

  20. 40Ar/39Ar Dating of Volcanic Glass

    NASA Astrophysics Data System (ADS)

    Morgan, L. E.; Renne, P. R.; Watkins, J. M.

    2007-12-01

    Application of the 40Ar/39Ar method to volcanic glasses has been somewhat stigmatized following several studies demonstrating secondary mobility of K and Ar. Much of the stigma is unwarranted, however, since most studies only impugned the reliability of the K-Ar and 40Ar/39Ar techniques when applied to glass shards rather than obsidian clasts with low surface area to volume ratios. We provide further evidence for problematic K loss and/or 39Ar recoil ejection from glass shards in 40Ar/39Ar step heating results for comagmatic feldspars and shards. In an extreme case, the plateau age of the feldspars (0.17 ± 0.03 Ma at 2σ) is significantly younger than the plateau age of the glass (0.85 ± 0.05 Ma at 2σ). If the feldspar age is reasonably interpreted as the eruption age of the ash, it is likely that the glass shards experienced K and/or 39Ar loss. Electron microprobe analyses of the glass shards have low totals (~93%) and no systematic lateral variability (i.e., diffusion gradients) in K, suggesting that the lengthscale of the glass shards is smaller than the lengthscale of K diffusion. Obsidian clasts should not be as susceptible to K loss since any hydrated (K-depleted) volume represents a small fraction of the total material and can often be physically removed prior to analysis. Samples described here are detrital obsidian clasts from the Afar region of Ethiopia. Evidence from Fourier Transform Infrared Spectroscopy (FTIR), and previous work by Anovitz (1999), confirm that the scale of water and potassium mobility are often small in comparison to the size of obsidian clasts but large enough to effect the bulk composition of glass shards. This expectation is confirmed in another tuff wherein comagmatic obsidian clasts and sanidine phenocrysts yield indistinguishable 40Ar/39Ar ages of 4.4 Ma High abundances of non-radiogenic 40Ar, and kinetic fractionation of Ar isotopes during quenching and/or laboratory degassing resulting in incomplete equilibration between

  1. Combined K-Ar and 40Ar/39Ar dating of the upper Jaramillo reversal

    NASA Astrophysics Data System (ADS)

    Guillou, Herve; Carracedo, Juan Carlos; Kissel, Catherine; Laj, Carlo; Nomade, Sebastien; Perez Torrado, Francisco Jose; Rodriguez Gonzalez, Alejandro; Wandres, Camille

    2013-04-01

    The Jaramillo subchron was first evidenced in 1966 (Doell and Dalrymple) through the Rhyolotic domes of the Valles Caldera, New Mexico (USA). 40Ar/39Ar studies achieved by Spell et McDougall (1992), Spell et Harrison (1993), Izett and Obradovich (1994) and Singer et al. (1994) defined the base of this subchron at 1053±6 ka, and the ceiling at 986±5 ka. Channell et al. (2009) delimited the age of the Jaramillo subchron by astronomic calibration (base 1071 ka, top 990 ka). To provide additional absolute ages on this geomagnetic period, which is critical to improve our knowledge of the earth magnetic field behaviour, we have carried out a study combining paleomagnetism and isotopic dating of a lava sequence from Tenerife island. This sequence of basaltic lava flows is some 500 m thick. The first 400 m present, based on field magnetometer measurements, normal polarity lavas, with dykes of normal and reverse polarity, passing at the top to reverse polarity lavas. Preliminary K-Ar ages bracketed this sequence between 1018 ± 18 ka and 978 ± 17 ka. Therefore, the upper Jaramillo reversal at least appeared to be potentially recorded in this sequence. A more detailed paleomagnetic study was then carried out to more precisely delimit the reversal itself (see Laj et al., session EMRP3.4). We have undertaken 40Ar/39Ar incremental heating and unspiked K-Ar experiments on groundmass from four transitionally magnetized flows. The first transitional flow is K-Ar dated at 993 ± 18 ka and 40Ar/39Ar dated at 991 ± 13 ka, the second at 981 ± 17 ka (K-Ar) and 1000 ± 13 ka (40Ar/39Ar), the third at 950 ± 17 ka (K-Ar) and 1000 ± 8 ka (40Ar/39Ar) and the fourth at 984 ± 17 ka (K-Ar) and 977 ± 12 (40Ar/39Ar). 40Ar/39Ar ages and K-Ar ages (relative to FCT 28.02 Ma) are indistinguishable at 2σ. The age of the upper boundary of the Jaramillo event calculated combining 40Ar/39Ar ages and K-Ar ages is 992 ± 6 ka, in agreement with previous estimates.

  2. Photoionization of Ar VIII

    NASA Astrophysics Data System (ADS)

    Liang, Liang; Jiang, Wen-xian; Zhou, Chao

    2017-01-01

    The photoionization cross section, energy levels and widths of 22 Rydberg series (in the autoionization region) for Na-like Ar VIII were investigated by using of R-matrix method. The relativistic distorted-wave method is used to calculate the radial functions, and QB method of Quigly-Berrington [Quigley et al. 1998] is employed to calculate the resonance levels and widths. We have identified the formant in the figure of the photoionization cross section.

  3. What Is a Recessive Allele?

    ERIC Educational Resources Information Center

    American Biology Teacher, 1991

    1991-01-01

    Presents four misconceptions students have concerning the concepts of recessive and dominant alleles. Discusses the spectrum of dominant-recessive relationships, different levels of analysis between phenotype and genotype, possible causes of dominance, and an example involving wrinkled peas. (MDH)

  4. Choreography of Ig allelic exclusion.

    PubMed

    Cedar, Howard; Bergman, Yehudit

    2008-06-01

    Allelic exclusion guarantees that each B or T cell only produces a single antigen receptor, and in this way contributes to immune diversity. This process is actually initiated in the early embryo when the immune receptor loci become asynchronously replicating in a stochastic manner with one early and one late allele in each cell. This distinct differential replication timing feature then serves an instructive mark that directs a series of allele-specific epigenetic events in the immune system, including programmed histone modification, nuclear localization and DNA demethylation that ultimately bring about preferred rearrangement on a single allele, and this decision is temporally stabilized by feedback mechanisms that inhibit recombination on the second allele. In principle, these same molecular components are also used for controlling monoallelic expression at other genomic loci, such as those carrying interleukins and olfactory receptor genes that require the choice of one gene out of a large array. Thus, allelic exclusion appears to represent a general epigenetic phenomenon that is modeled on the same basis as X chromosome inactivation.

  5. A natural laboratory for 40Ar/39Ar geochronology: ICDP cores from Lake Van, Turkey

    NASA Astrophysics Data System (ADS)

    Engelhardt, Jonathan; Sudo, Masafumi; Oberhänsli, Roland

    2015-04-01

    Pore water samples from ICDP Paleovan cores indicate a limited pore water exchange within Quaternary lake sediments. The core's volcaniclastic sections bear unaltered K-rich ternary feldspar and fresh to altered glass shards of predominantly rhyolitic composition. Whereas applying the 40Ar/39Ar method on feldspars resulted in ages timing a late-stage crystallization, glass shards had the potential to date the eruption. Volcanic glass is prone to modifications such as hydrous alteration (palagonitization) and devitrification (Cerling et al., 1985). These modifications affect the glass' chemistry and challenge the application of the 40Ar/39Ar method. Gaining precise radiometric ages from two phases has the potential to strengthen a climate-stratigraphic age-model (Stockhecke et al., 2014), and to significantly increase the temporal resolution on the deposition of the lake sediments. Vice versa the core's previous age model has the ability to question the reliability of 40Ar/39Ar eruption ages derived from ternary feldspars and glass shards. Multi- and single-grain total fusion on alkali feldspars from six volcaniclastic deposits resulted in Pleistocene ages that are in good agreement with the predicted age model. Feldspar phenocrysts from three ashes in the core's youngest section yielded consistent isochron ages that are significantly older than the model's prediction. Several distinct stratigraphic and paleomagnetic time markers of similar stratigraphic positions contradict to the older radiometric dates (Stockhecke et al., 2014). Partial resorption features of inherited feldspar domains and the involvement of excess 40Ar indicate incomplete degassing of older domains. To evaluate the magmatic history of the different domains EMPA mappings of trace elements that could be interpreted as Ar diffusion couples are currently conducted. Geochronology on Paleovan cores offers unique opportunities to monitor the effect of alteration on the Ar-systematics of volcanic glass

  6. Registration of hard kernel puroindoline allele nearisogenic line hexaploid wheat genetic stocks.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seven puroindoline allele near-isogenic line (NIL) hexaploid wheat (Triticum aestivum L.) genetic stocks (GS-xxxx – GS-xxxx; PI 644080 – PI 644086) were developed by Dr. Craig F. Morris at the USDA-ARS Western Wheat Quality Laboratory, Pullman, Washington. As they incorporate the first seven known ...

  7. USDA-ARS support of the USDA small watershed program

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The USDA-ARS Hydraulic Engineering Research Unit (HERU) has had a rich history supporting the USDA Small Watershed Program. The Small Watershed Program was established by the passage of legislation that allowed the USDA-Natural Resources Conservation Service to provide financial and technical suppo...

  8. AR Signaling in Breast Cancer

    PubMed Central

    Rahim, Bilal; O’Regan, Ruth

    2017-01-01

    Androgen receptor (AR, a member of the steroid hormone receptor family) status has become increasingly important as both a prognostic marker and potential therapeutic target in breast cancer. AR is expressed in up to 90% of estrogen receptor (ER) positive breast cancer, and to a lesser degree, human epidermal growth factor 2 (HER2) amplified tumors. In the former, AR signaling has been correlated with a better prognosis given its inhibitory activity in estrogen dependent disease, though conversely has also been shown to increase resistance to anti-estrogen therapies such as tamoxifen. AR blockade can mitigate this resistance, and thus serves as a potential target in ER-positive breast cancer. In HER2 amplified breast cancer, studies are somewhat conflicting, though most show either no effect or are associated with poorer survival. Much of the available data on AR signaling is in triple-negative breast cancer (TNBC), which is an aggressive disease with inferior outcomes comparative to other breast cancer subtypes. At present, there are no approved targeted therapies in TNBC, making study of the AR signaling pathway compelling. Gene expression profiling studies have also identified a luminal androgen receptor (LAR) subtype that is dependent on AR signaling in TNBC. Regardless, there seems to be an association between AR expression and improved outcomes in TNBC. Despite lower pathologic complete response (pCR) rates with neoadjuvant therapy, patients with AR-expressing TNBC have been shown to have a better prognosis than those that are AR-negative. Clinical studies targeting AR have shown somewhat promising results. In this paper we review the literature on the biology of AR in breast cancer and its prognostic and predictive roles. We also present our thoughts on therapeutic strategies. PMID:28245550

  9. AR Signaling in Breast Cancer.

    PubMed

    Rahim, Bilal; O'Regan, Ruth

    2017-02-24

    Androgen receptor (AR, a member of the steroid hormone receptor family) status has become increasingly important as both a prognostic marker and potential therapeutic target in breast cancer. AR is expressed in up to 90% of estrogen receptor (ER) positive breast cancer, and to a lesser degree, human epidermal growth factor 2 (HER2) amplified tumors. In the former, AR signaling has been correlated with a better prognosis given its inhibitory activity in estrogen dependent disease, though conversely has also been shown to increase resistance to anti-estrogen therapies such as tamoxifen. AR blockade can mitigate this resistance, and thus serves as a potential target in ER-positive breast cancer. In HER2 amplified breast cancer, studies are somewhat conflicting, though most show either no effect or are associated with poorer survival. Much of the available data on AR signaling is in triple-negative breast cancer (TNBC), which is an aggressive disease with inferior outcomes comparative to other breast cancer subtypes. At present, there are no approved targeted therapies in TNBC, making study of the AR signaling pathway compelling. Gene expression profiling studies have also identified a luminal androgen receptor (LAR) subtype that is dependent on AR signaling in TNBC. Regardless, there seems to be an association between AR expression and improved outcomes in TNBC. Despite lower pathologic complete response (pCR) rates with neoadjuvant therapy, patients with AR-expressing TNBC have been shown to have a better prognosis than those that are AR-negative. Clinical studies targeting AR have shown somewhat promising results. In this paper we review the literature on the biology of AR in breast cancer and its prognostic and predictive roles. We also present our thoughts on therapeutic strategies.

  10. AR-39-AR-40 "Age" of Basaltic Shergottite NWA-3171

    NASA Technical Reports Server (NTRS)

    Bogard, Donald D.; Park, Jisun

    2007-01-01

    North-West-Africa 3171 is a 506 g, relatively fresh appearing, basaltic shergottite with similarities to Zagami and Shergotty, but not obviously paired with any of the other known African basaltic shergottites. Its exposure age has the range of 2.5-3.1 Myr , similar to those of Zagami and Shergotty. We made AR-39-AR-40 analyses of a "plagioclase" (now shock-converted to maskelynite) separate and of a glass hand-picked from a vein connected to shock melt pockets.. Plagioclase was separated using its low magnetic susceptibility and then heavy liquid with density of <2.85 g/cm(exp 3). The AR-39-AR-40 age spectrum of NWA-317 1 plag displays a rise in age over 20-100% of the 39Ar release, from 0.24 Gyr to 0.27 Gy.

  11. 40Ar/39Ar Studies of Antarctic Micrometeorites

    NASA Astrophysics Data System (ADS)

    Saxton, J. M.; Knott, S. F.; Turner, G.; Maurette, M.

    1992-07-01

    We have used the ^40Ar/^39Ar technique to study eight dust particles, in the size range 50-100 microns, collected by filtering Antarctic blue ice (Maurette et al. 1989). The particles were pressed into aluminium foil and their compositions estimated using SEM/EDX techniques. Six were found to have approximately chondritic Mg/Fe/Si ratios, suggesting an extraterrestrial origin. The remaining two particles appeared to be composed mostly of iron and we are not sure of their origin. The particles were then irradiated with a fast neutron fluence of approximately 6 x 10^18 cm^-2, and the argon in them extracted using a pulsed laser delivering about 100 mJ per pulse. We attempted to step heat most of the particles by initially defocusing the beam to reduce the heating effect. In four cases, a sufficient amount of gas was released for step heating to be profitable. The results for five of the chondritic particles are shown in the figure. One yielded a very small amount of gas and is not plotted. The high temperature step is shown for those particles that were step heated. In this diagram, air plots on the y-axis (^36Ar/^40Ar = 0.00338), a purely radiogenic component plots on the x-axis, and addition of ^36Ar moves a point vertically upwards. Four particles have ^36Ar/^40Ar ratios higher than air. This confirms their extraterrestrial origin. We believe the 36Ar is most probably derived from solar energetic particles; only 10^2-10^3 years exposure at 1 AU would be required to produce the level of ^36Ar we observe (10^-12-10^-13 ccSTP), assuming that no 36Ar is lost during atmospheric passage. This is comfortably less than the time taken for a particle of this size to drift in from 2AU to 1AU due to the Poynting Robertson effect, which is of the order 10^5 years. The concentration ^36Ar content is of the order of 10^-7-10^-6 g^-1, which is comparable to the levels of trapped ^36Ar found in primitive meteorites. This interpretation of the source of the ^36Ar would seem to

  12. Comparison of conventional K-Ar and 40Ar/39Ar dating of young mafic volcanic rocks

    USGS Publications Warehouse

    Lanphere, M.A.

    2000-01-01

    K-Ar and 40Ar/39Ar ages have been measured on nine mafic volcanic rocks younger than 1 myr from the Snake River Plain (Idaho), Mount Adams (Washington), and Crater Lake (Oregon). The K-Ar ages were calculated from Ar measurements made by isotope dilution and K2O measurements by flame photometry. The 40Ar/39Ar ages are incremental-heating experiments using a low-blank resistance-heated furnace. The results indicate that high-quality ages can be measured on young, mafic volcanic rocks using either the K-Ar or the 40Ar/39Ar technique. The precision of an 40Ar/39Ar plateau age generally is better than the precision of a K-Ar age because the plateau age is calculated by pooling the ages of several gas increments. The precision of a plateau age generally is better than the precision of an isotope correlation (isochron) age for the same sample. For one sample the intercept of the isochron yielded an 40Ar/36Ar value significantly different from the atmospheric value of 295.5. Recalculation of increment ages using the isochron intercept for the composition of nonradiogenic Ar in the sample resulted in much better agreement of ages for this sample. The results of this study also indicate that, given suitable material and modern equipment, precise K-Ar and 40Ar/39Ar ages can be measured on volcanic rocks as young as the latest Pleistocene, and perhaps even the Holocene.

  13. Ar-40/Ar-39 dating, Ar diffusion properties, and cooling rate determinations of severely shocked chondrites

    NASA Technical Reports Server (NTRS)

    Bogard, D. D.; Hirsch, W. C.

    1980-01-01

    The ages of Ar-40/Ar-39 chondrites were computed to be 4.29 to 1.0 Gyr, with degassing times of 0.5 to 1.0 Gyr. The values of the diffusion parameter for Ar in Arrhenius plots show linear relationships which correspond to the degassing of different mineral phases with distinct K/Ca ratios and different average temperatures for Ar release. The experimental values of the diffusion parameter for the high-temperature phase of severely shocked chondrites are 10 to the -7th to 10 to the -5th/s for the shock-heating temperatures in the 950-1200 C range; the inferred reheating temperatures and the fraction of the Ar-40 loss during the reheating event suggest post-shock cooling rates and burial depths of 0.01-0.0001 C/s and 0.5-2m, respectively.

  14. ARS-Media for excel instruction manual

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ARS-Media for Excel Instruction Manual is the instruction manual that explains how to use the Excel spreadsheet ARS-Media for Excel application. ARS-Media for Excel Instruction Manual is provided as a pdf file....

  15. Experimental M1 Transition Rates of Coronal Lines from AR X, AR XIV, and AR XV

    NASA Astrophysics Data System (ADS)

    Träbert, E.; Beiersdorfer, P.; Utter, S. B.; Brown, G. V.; Chen, H.; Harris, C. L.; Neill, P. A.; Savin, D. W.; Smith, A. J.

    2000-09-01

    Transition probabilities of three magnetic dipole (M1) transitions in multiply charged ions of Ar have been measured using the Livermore electron-beam ion trap. Two of the transitions are in the ground configurations of Ar XIV (B-like) and Ar IX (F-like), and are associated with the coronal lines at 4412.4 and 5533.4 Å, respectively. The third is in the excited 2s2p configuration of Be-like Ar XV and produces the coronal line at 5943.73 Å. Our results for the three atomic level lifetimes are 9.32+/-0.12 ms for the Ar X 2s22p5 2Po1/2 level, 9.70+/-0.15 ms for the Ar XIV 2s22p 2Po3/2 level, and 15.0+/-0.8 ms for the Ar XV 2s2p 3Po2 level. These results differ significantly from earlier measurements and are the most accurate ones to date.

  16. Identification of novel alleles of the rice blast resistance gene Pi54

    NASA Astrophysics Data System (ADS)

    Vasudevan, Kumar; Gruissem, Wilhelm; Bhullar, Navreet K.

    2015-10-01

    Rice blast is one of the most devastating rice diseases and continuous resistance breeding is required to control the disease. The rice blast resistance gene Pi54 initially identified in an Indian cultivar confers broad-spectrum resistance in India. We explored the allelic diversity of the Pi54 gene among 885 Indian rice genotypes that were found resistant in our screening against field mixture of naturally existing M. oryzae strains as well as against five unique strains. These genotypes are also annotated as rice blast resistant in the International Rice Genebank database. Sequence-based allele mining was used to amplify and clone the Pi54 allelic variants. Nine new alleles of Pi54 were identified based on the nucleotide sequence comparison to the Pi54 reference sequence as well as to already known Pi54 alleles. DNA sequence analysis of the newly identified Pi54 alleles revealed several single polymorphic sites, three double deletions and an eight base pair deletion. A SNP-rich region was found between a tyrosine kinase phosphorylation site and the nucleotide binding site (NBS) domain. Together, the newly identified Pi54 alleles expand the allelic series and are candidates for rice blast resistance breeding programs.

  17. Identification of novel alleles of the rice blast resistance gene Pi54.

    PubMed

    Vasudevan, Kumar; Gruissem, Wilhelm; Bhullar, Navreet K

    2015-10-26

    Rice blast is one of the most devastating rice diseases and continuous resistance breeding is required to control the disease. The rice blast resistance gene Pi54 initially identified in an Indian cultivar confers broad-spectrum resistance in India. We explored the allelic diversity of the Pi54 gene among 885 Indian rice genotypes that were found resistant in our screening against field mixture of naturally existing M. oryzae strains as well as against five unique strains. These genotypes are also annotated as rice blast resistant in the International Rice Genebank database. Sequence-based allele mining was used to amplify and clone the Pi54 allelic variants. Nine new alleles of Pi54 were identified based on the nucleotide sequence comparison to the Pi54 reference sequence as well as to already known Pi54 alleles. DNA sequence analysis of the newly identified Pi54 alleles revealed several single polymorphic sites, three double deletions and an eight base pair deletion. A SNP-rich region was found between a tyrosine kinase phosphorylation site and the nucleotide binding site (NBS) domain. Together, the newly identified Pi54 alleles expand the allelic series and are candidates for rice blast resistance breeding programs.

  18. Photosynthetic and antioxidant responses of Liquidambar formosana and Schima superba seedlings to sulfuric-rich and nitric-rich simulated acid rain.

    PubMed

    Chen, Juan; Wang, Wen-Hua; Liu, Ting-Wu; Wu, Fei-Hua; Zheng, Hai-Lei

    2013-03-01

    To study whether differential responses occur in photosynthesis and antioxidant system for seedlings of Liquidambar formosana, an acid rain (AR)-sensitive tree species and Schima superba, an AR-tolerant tree species treated with three types of pH 3.0 simulated AR (SiAR) including sulfuric-rich (S-SiAR), nitric-rich (N-SiAR), sulfate and nitrate mixed (SN-SiAR), we investigated the changes of leaf necrosis, chlorophyll content, soluble protein and proline content, photosynthesis and chlorophyll fluorescence characteristics, reactive oxygen species production, membrane lipid peroxidation, small molecular antioxidant content, antioxidant enzyme activities and related protein expressions. Our results showed that SiAR significantly caused leaf necrosis, inhibited photosynthesis, induced superoxide radical and hydrogen peroxide generation, aggravated membrane lipid peroxidation, changed antioxidant enzyme activities, modified related protein expressions such as Cu/Zn superoxide dismutase (SOD), l-ascorbate peroxidase (APX, EC 1. 11. 1. 11), glutathione S transferase (GST, EC 2. 5. 1. 18) and Rubisco large subunit (RuBISCO LSU), altered non-protein thiols (NPT) and glutathione (GSH) content in leaves of L. formosana and S. superba. Taken together, we concluded that the damages caused by SiAR in L. formosana were more severe and suffered from more negative impacts than in S. superba. S-SiAR induced more serious damages for the plants than did SN-SiAR and N-SiAR.

  19. Ar-39-Ar-40 Ages of Two Nakhlites, MIL03346 and Y000593: A Detailed Analysis

    NASA Technical Reports Server (NTRS)

    Park, Jisun; Garrison, Daniel; Bogard, Donald

    2007-01-01

    Radiometric dating of martian nakhlites by several techniques have given similar ages of approx.1.2-1.4 Ga [e.g. 1, 2]. Unlike the case with shergottites, where the presence of martian atmosphere and inherited radiogenic Ar-40 produce apparent Ar-39-Ar-40 ages older than other radiometric ages, Ar-Ar ages of nakhlites are similar to ages derived by other techniques. However, even in some nakhlites the presence of trapped martian Ar produces some uncertainty in the Ar-Ar age. We present here an analysis of such Ar-Ar ages from the MIL03346 and Y000593 nakhlites.

  20. Unmixing 40Ar/39Ar Muscovite Ages Using Powder X-ray Diffraction

    NASA Astrophysics Data System (ADS)

    McAleer, R. J.; Kunk, M. J.; Valley, P. M.; Walsh, G. J.; Bish, D. L.; Wintsch, R. P.

    2014-12-01

    Whole rock powder X-ray diffraction (XRD) experiments from eight samples collected across a retrograde ductile shear zone in the Devonian Littleton Formation near Claremont, NH, exhibit broad and asymmetric to bimodal muscovite 00l reflections. These composite 00l reflections exhibit a systematic change in shape with increasing retrograde strain. Microtextural relationships, electron microprobe quantitative analyses, and element mapping indicate that the change in peak shape reflects progressive dissolution of metastable Na-rich muscovite and the precipitation of stable Na-poor muscovite. 40Ar/39Ar step heating experiments on muscovite concentrates from these samples show a decrease in total gas age from 274 to 258 Ma as the highest strain zone is approached, and steps within individual spectra range in age by ~20 m.y. The correlation between age and 00l peak shape suggests that the argon isotopic system also tracks the dissolution-precipitation process. Furthermore, the variation in age during step heating indicates that these populations exhibit different in-vacuo degassing behavior. Comparison of whole rock and muscovite concentrate XRD patterns from the same samples shows that the mineral separation process can fractionate these muscovite populations. With this knowledge, four muscovite concentrates were prepared from a single hand sample, analyzed by XRD, and dated. Combining modal estimates from XRD experiments with total gas ages, the four splits narrowly define a mixing line that resolves end-member ages of 250 and 300 Ma for the neocrystallized and earlier high grade populations of muscovite, respectively. These ages are consistent with age data from all other samples. The results show that, in some settings, powder XRD provides a powerful and time effective method to both identify the existence of and establish the proportions of multiple compositional populations of muscovite prior to 40Ar/39Ar analysis. This approach will be especially useful in

  1. An Astronomically Dated Standard in 40Ar/39Ar Geochronology?

    NASA Astrophysics Data System (ADS)

    Kuiper, K.; Hilgen, F.; Krijgsman, W.; Wijbrans, J.

    2003-12-01

    The standard geological time scale of Berggren et al. (1995) and Cande and Kent (1995) is calibrated with different absolute dating techniques, i.e. the Plio - Pleistocene relies on astronomical tuning, and older parts of the time scale are based on radio-isotopic (40Ar/39Ar and U/Pb) calibration methods. In the new edition of the standard geological timescale (Lourens et al., to be published in 2004) the entire Neogene will rely on astronomical dating. Therefore, it is of crucial importance that all dating methods produce equivalent absolute ages when the same geological event is dated. The Mediterranean Neogene provides an excellent opportunity to compare different dating methods by isotopic dating (40Ar/39Ar, U/Pb) of volcanic ash layers intercalated in astronomically dated sediments. Here we will show that in spite of potential errors in all methods, we succeeded to intercalibrate the 40Ar/39Ar and astronomical methods, arriving at astronomically calibrated age of 28.24 +/- 0.01 Ma for the in 40Ar/39Ar geochronology commonly used standard FCT sanidine. The advantage of an astronomically calibrated FCT above a K/Ar calibrated standard is a smaller error in the absolute age due to the lack of uncertainties related to 40K and radiogenic 40Ar contents in the primary standard and a decreasing influence of errors in the decay constant (branching ratio is not required). In addition to an astronomically calibrated FCT age we propose to introduce an astronomically dated standard. A direct astronomically dated standard can be regarded as a "primary" standard and does not require intercalibration with other standards, thus reducing analytical (and geological) uncertainties. Ash layers intercalated in sedimentary sequences in the Melilla Basin, Morocco appear to be the most suitable for this purpose. A reliable astronomical time control is available and intercalated ash layers contain sanidine phenocrysts up to 2 mm. Four ash layers are not or barely affected by

  2. Low-Lying Structure of 50Ar and the N =32 Subshell Closure

    NASA Astrophysics Data System (ADS)

    Steppenbeck, D.; Takeuchi, S.; Aoi, N.; Doornenbal, P.; Matsushita, M.; Wang, H.; Utsuno, Y.; Baba, H.; Go, S.; Lee, J.; Matsui, K.; Michimasa, S.; Motobayashi, T.; Nishimura, D.; Otsuka, T.; Sakurai, H.; Shiga, Y.; Shimizu, N.; Söderström, P.-A.; Sumikama, T.; Taniuchi, R.; Valiente-Dobón, J. J.; Yoneda, K.

    2015-06-01

    The low-lying structure of the neutron-rich nucleus 50Ar has been investigated at the Radioactive Isotope Beam Factory using in-beam γ -ray spectroscopy with 9Be (54Ca, 50Ar +γ )X , 9Be (55Sc, 50Ar +γ )X , and 9Be (56Ti, 50Ar +γ )X multinucleon removal reactions at ˜220 MeV /u . A γ -ray peak at 1178(18) keV is reported and assigned as the transition from the first 2+ state to the 0+ ground state. A weaker, tentative line at 1582(38) keV is suggested as the 41+→21+ transition. The experimental results are compared to large-scale shell-model calculations performed in the s d p f model space using the SDPF-MU effective interaction with modifications based on recent experimental data for exotic calcium and potassium isotopes. The modified Hamiltonian provides a satisfactory description of the new experimental results for 50Ar and, more generally, reproduces the energy systematics of low-lying states in neutron-rich Ar isotopes rather well. The shell-model calculations indicate that the N =32 subshell gap in 50Ar is similar in magnitude to those in 52Ca and 54Ti and, notably, predict an N =34 subshell closure in 52Ar that is larger than the one recently reported in 54Ca.

  3. Ar-Ar Analysis of Chelyabinsk: Evidence for a Recent Impact

    NASA Technical Reports Server (NTRS)

    Beard, S. P.; Kring, D. A.; Isachsen, C. E.; Lapen, T. J.; Zolensky, M. E.; Swindle, T. D.

    2014-01-01

    The Chelyabinsk meteorite is an LL5 ordinary chondrite that fell as a spectacular fireball on February 15th, 2013, over the Ural region in Russia. The meteoroid exploded at an altitude of 25-30 km, producing shockwaves that broke windowpanes in Chelyabinsk and surrounding areas, injuring some 1500 people. Analyses of the samples show that the meteorite underwent moderate shock metamorphism (stage S4; 25-35 GPa) [1]. Most of the samples have a fusion crust ranging from 0.1-1mm thick, and roughly a third of the samples were composed of a dark fine-grained impact melt with chondrule fragments which were targeted for chronometry. A Pb-Pb age obtained by [2] of a shock-darkened and potentially melted sample of Chelyabinsk is reported as 4538.3 +/- 2.1 Ma, while a U-Pb study [3] gave an upper concordia intercept of 4454 +/- 67 Ma and a lower intercept of 585 +/- 390. Galimov et al. 2013 [1] suggest the Sm-Nd system records a recent impact event [290 Ma] that may represent separation from the parent body, while the Rb-Sr isotopic system is disturbed and does not give any definitive isochron. In order to better understand its history, we have performed 40Ar-39Ar analysis on multiple splits of two Chelyabinsk samples; clast- rich MB020f,2 and melt-rich MB020f,5. The term "clast-rich" lithology is meant to indicate a mechanical mixture of highly shock-darkened and less shocked components, both with some shock melt veining.

  4. 39Ar-40Ar "ages" and origin of excess 40Ar in Martian shergottites

    NASA Astrophysics Data System (ADS)

    Bogard, Donald; Park, Jisun; Garrison, Daniel

    2009-06-01

    We report new 39Ar-40Ar measurements on 15 plagioclase, pyroxene, and/or whole rock samples of 8 Martian shergottites. All age spectra suggest ages older than the meteorite formation ages, as defined by Sm-Nd and Rb-Sr isochrons. Employing isochron plots, only Los Angeles plagioclase and possibly Northwest Africa (NWA) 3171 plagioclase give ages in agreement with their formation ages. Isochrons for all shergottite samples reveal the presence of trapped Martian 40Ar (40Arxs), which exists in variable amounts in different lattice locations. Some 40Arxs is uniformly distributed throughout the lattice, resulting in a positive isochron intercept, and other 40Arxs occurs in association with K-bearing minerals and increases the isochron slope. These samples demonstrate situations where linear Ar isochrons give false ages that are too old. After subtracting 40Ar*that would accumulate by 40K decay since meteorite formation and small amounts of terrestrial 40Ar, all young age samples give similar 40Arxs concentrations of ˜1-2 × 10-6cm3/g, but a variation in K content by a factor of ˜80. Previously reported NASA Johnson Space Center data for Zagami, Shergotty, Yamato (Y-) 000097, Y-793605, and Queen Alexandra Range (QUE) 94201 shergottites show similar concentrations of 40Arxs to the new meteorite data reported here. Similar 40Arxs in different minerals and meteorites cannot be explained as arising from Martian atmosphere carried in strongly shocked phases such as melt veins. We invoke the explanation given by Bogard and Park (2008) for Zagami, that this 40Arxs in shergottites was acquired from the magma. Similarity in 40Arxs among shergottites may reveal common magma sources and/or similar magma generation and emplacement processes.

  5. The ArDM Experiment

    NASA Astrophysics Data System (ADS)

    Bueno, A.; Ardm Collaboration

    2007-08-01

    We describe the Argon Dark Matter (ArDM) experiment. It consists on a one-ton liquid argon detector able to read independently ionization charge and scintillation light. This device has been optimized to perform a direct search for Weakly Interacting Massive Particles (WIMPs).

  6. ARS-Media for Excel

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ARS-Media for Excel is an ion solution calculator that uses Microsoft Excel to generate recipes of salts for complex ion mixtures specified by the user. Generating salt combinations (recipes) that result in pre-specified target ion values is a linear programming problem. Thus, the recipes are genera...

  7. USDA-ARS Quartlerly News

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This quarterly article is an update of research going on at The USDA-ARS Thad Cochran Southern Horticultural Laboratory in Poplarville, MS to be published in the Louisiana Nursery and Landscape Associations (LANLA) quarterly newsletter. This is one of three publications that I am sending out to the ...

  8. A novel measurement of allele discrimination for assessment of allele-specific silencing by RNA interference.

    PubMed

    Takahashi, Masaki; Hohjoh, Hirohiko

    2014-11-01

    Allele-specific silencing by RNA interference (ASP-RNAi) is an atypical RNAi that is capable of discriminating target alleles from non-target alleles, and may be therapeutically useful for specific inhibition of disease-causing alleles without affecting their corresponding normal alleles. However, it is difficult to design and select small interfering RNA (siRNAs) that confer ASP-RNAi. A major problem is that there are few appropriate measures in determining optimal allele-specific siRNAs. Here we show two novel formulas for calculating a new measure of allele-discrimination, named "ASP-score". The formulas and ASP-score allow for an unbiased determination of optimal siRNAs, and may contribute to characterizing such allele-specific siRNAs.

  9. Armenian Astronomical Society (ArAS) activities

    NASA Astrophysics Data System (ADS)

    Mickaelian, A. M.

    2016-09-01

    A review on the activities and achievements of Armenian Astronomical Society (ArAS) and Armenian astronomy in general during the last years is given. ArAS membership, ArAS electronic newsletters (ArASNews), ArAS webpage, Annual Meetings, Annual Prize for Young Astronomers (Yervant Terzian Prize) and other awards, international relations, presence in international organizations, local and international summer schools, science camps, astronomical Olympiads and other events, matters related to astronomical education, astronomical heritage, amateur astronomy, astronomy outreach and ArAS further projects are described and discussed.

  10. Allelic selection of human IL-2 gene.

    PubMed

    Matesanz, F; Delgado, C; Fresno, M; Alcina, A

    2000-12-01

    The allelic expression of mouse IL-2 cannot be definitely extrapolated to what might happen in humans. Therefore, we investigated the regulation of allelic expression of the IL-2 gene in non-genetically manipulated human T lymphocytes by following natural allelic polymorphisms. We found a phenotypically silent punctual change in the human IL-2 at position 114 after the first nucleotide of the initiation codon, which represents a dimorphic polymorphism at the first exon of the IL-2 gene. This allowed the study by single-cell PCR of the regulation of the human IL-2 allelic expression in heterozygous CD4(+) T cells, which was found to be tightly controlled monoallelically. These findings may be used as a suitable marker for monitoring the IL-2 allelic contribution to effector activities and in immune responses against different infections or in pathological situations.

  11. Oldest human footprints dated by Ar/Ar

    NASA Astrophysics Data System (ADS)

    Scaillet, Stéphane; Vita-Scaillet, Grazia; Guillou, Hervé

    2008-11-01

    Fossilized human trackways are extremely rare in the geologic record. These bear indirect but invaluable testimony of human/hominid locomotion in open air settings and can provide critical information on biomechanical changes relating to bipedalism evolution throughout the primitive human lineage. Among these, the "Devil's footsteps" represent one of the best preserved human footprints suite recovered so far in a Pleistocene volcanic ash of the Roccamonfina volcano (southern Italy). Until recently, the age of these footprints remained speculative and indirectly correlated with a loosely dated caldera-forming eruption that produced the Brown Leucitic Tuff. Despite extensive hydrothermal alteration of the pyroclastic deposit and variable contamination with excess 40Ar, detailed and selective 40Ar/ 39Ar laser probe analysis of single leucite crystals recovered from the ash deposit shows that the pyroclastic layer and the footprints are 345 ± 6 kyr old (1 σ), confirming for the first time that these are the oldest human trackways ever dated, and that they were presumably left by the modern human predecessor, Homo heidelbergensis, close to Climatic Termination IV.

  12. Mineralogy and Ar-39 - Ar-40 of an old pristine basalt: Thermal history of the HED parent body

    NASA Technical Reports Server (NTRS)

    Takeda, Hiroshi; Mori, Hiroshi; Bogard, Donald D.

    1994-01-01

    Previous investigations of mineral chemistry and Rb-Sr and Sm-Nd ages indicated that clast,84 from eucrite Yamato 75011 had preserved the pristine nature of its initial crystallization during an early stage of the HED parent body. Microscale mineralogy and Ar-39-Ar-40 ages of this clast, however, revealed local disturbance of microtextures and partially reset ages. This evidence suggests that, in addition to initial crystallization and rapid cooling, the Y75011,84 clast experienced shock deformation, reheating of short duration at higher temperature, and brecciation. These characteristics suggest two or more impact events. Fe-rich olivine filling fractures in pyroxene may have been introduced during the accompanying shock fracturing. The inferred Ar-39-Ar-40 degassing ages for Y75011 matrix and clast, 84 are 3.94 +/- 0.04 Ga and 3.98 +/- 0.03 Ga, respectively. The suggested degassing age for a clast from Y790020, believed to be paired with Y75011, is approximately 4.03 Ga, but could be younger. We consider it likely that all three samples experienced a common degassing event 3.95 +/- 0.05 Ga ago, but we cannot rule out two or more events spaced over a approximately 0.1 Ga interval. Higher temperature extractions of the two clast samples show significantly older apparent ages up to approximately 4.5 Ga and suggest that the time/temperature regime of this event was not sufficient to degas Ar totally. Most likely, the K-Ar ages were reset by thermal metamorphism associated with one or more impact events associated with shock fracturing, formation of Fe-rich olivine veins, and/or meteorite brecciation. The pyroxene annealing that commonly occurs in many eucrites is likely to be a much earlier process than the impact-produced textural changes and reset K-Ar ages observed in these meteorites. The existence of mineralogical and chronological evidence for metamorphism in an otherwise pristine eucrite suggests that the HED parent body experienced an extensive degree of

  13. Variation of illite/muscovite 40Ar/39Ar age spectra during progressive low-grade metamorphism: an example from the US Cordillera

    NASA Astrophysics Data System (ADS)

    Verdel, Charles; van der Pluijm, Ben A.; Niemi, Nathan

    2012-09-01

    40Ar/39Ar step-heating data were collected from micron to submicron grain-sizes of correlative illite- and muscovite-rich Cambrian pelitic rocks from the western United States that range in metamorphic grade from the shallow diagenetic zone (zeolite facies) to the epizone (greenschist facies). With increasing metamorphic grade, maximum ages from 40Ar/39Ar release spectra decrease, as do total gas ages and retention ages. Previous studies have explained similar results as arising dominantly or entirely from the dissolution of detrital muscovite and precipitation/recrystallization of neo-formed illite. While recognizing the importance of these processes in evaluating our results, we suggest that the inverse correlation between apparent age and metamorphic grade is controlled, primarily, by thermally activated volume diffusion, analogous to the decrease in apparent ages with depth observed for many thermochronometers in borehole experiments. Our results suggest that complete resetting of the illite/muscovite Ar thermochronometer occurs between the high anchizone and epizone, or at roughly 300 °C. This empirical result is in agreement with previous calculations based on muscovite diffusion parameters, which indicate that muscovite grains with radii of 0.05-2 μm should have closure temperatures between 250 and 350 °C. At high anchizone conditions, we observe a reversal in the age/grain-size relationship (the finest grain-size produces the oldest apparent age), which may mark the stage in prograde subgreenschist facies metamorphism of pelitic rocks at which neo-formed illite/muscovite crystallites typically surpass the size of detrital muscovite grains. It is also approximately the stage at which neo-formed illite/muscovite crystallites develop sufficient Ar retentivity to produce geologically meaningful 40Ar/39Ar ages. Results from our sampling transect of Cambrian strata establish a framework for interpreting illite/muscovite 40Ar/39Ar age spectra at different

  14. Characterization of the treefrog null allele, 1991

    SciTech Connect

    Guttman, S.I.

    1992-04-01

    Spring peeper (Hyla crucifer) tadpoles collected from the waste storage area during the Biological and Ecological Site Characterization of the Feed Materials Production Center (FEMP) in 1986 and 1987 appeared to be unique. A null (inactive) allele was found at the glucose phosphate isomerase enzyme locus in significant frequencies (approximately 20%) each year; this allele did not appear to occur in the offsite sample collected approximately 15km from the FEMP. Null alleles at this locus have not been reported in other amphibian populations; when they have been found in other organisms they have invariably been lethal in the homozygous condition.

  15. Characterization of the treefrog null allele

    SciTech Connect

    Guttman, S.I. . Dept. of Zoology)

    1990-12-01

    As part of the authors intensive year-long baseline ecological study, they characterized the degree of genetic polymorphism and heterozygosity in selected Feed Materials Production Center (FMPC) populations using electrophoretic techniques. These data are being used as an indicator of stress by comparing populations on and off the FMPC site. The current study was initiated to determine whether this GPI null allele is lethal, when homozygous, in spring peepers. Also, a sampling protocol was implemented to determine whether a linear effect occurs relative to the frequency of the null allele offsite and to determine the origination site of the null allele. 18 refs., 2 figs., 4 tabs.

  16. arXiv.org and Physics Education

    ERIC Educational Resources Information Center

    Ramlo, Susan

    2007-01-01

    The website arXiv.org (pronounced "archive") is a free online resource for full-text articles in the fields of physics, mathematics, computer science, nonlinear science, and quantitative biology that has existed for about 15 years. Available directly at http://www.arXiv.org, this e-print archive is searchable. As of Jan. 3, 2007, arXiv had open…

  17. Ar-40/Ar-39 age determinations for the Rotoiti eruption, New Zealand

    NASA Astrophysics Data System (ADS)

    Flude, S.; Storey, M.

    2013-12-01

    The contemporaneous Rotoiti and Earthquake Flat ignimbrites, erupted from the Taupo Volcanic zone, New Zealand, form a distinctive tephrostratigraphic horizon in the Southern Pacific. Radioisotopic dating results for these eruptions remain controversial, with published ages ranging from 35.1 × 2.8 ka [1] to 71 × 6 ka [2], with 61.0 × 1.5 ka [3] often being cited as the most widely accepted age. These eruptions are difficult to date as their age is near the limit for various radiometric dating techniques, which are complicated by a large proportion of inherited material (xenocrysts) and a lack of phases suitable for dating. Glass-bearing plutonic blocks erupted with the Rotoiti and Earthquake Flat ignimbrites have previously been interpreted as deriving from a slowly cooled and incompletely solidified magma body that was sampled by the eruptions. They contain large vugs lined with euhedral quartz, sanidine and biotite crystals, indicating that these crystals grew in a gas or aqueous fluid rich environment and are interpreted to have formed shortly before or during eruption. Here we will present Ar-40/Ar-39 ages for sanidines and biotites extracted from vugs in lithic blocks erupted as part of the Earthquake Flat ignimbrite. We show that, even for vug-lining material, inherited ages remain a problem and are the likely source of the wide variation in published radiometric ages. Nevertheless, many of the Ar-40/Ar-39 ages are much younger than the 61 ka age [3] and are more consistent with the recent stratigraphic, C-14 and U-238/Th-230+(U-Th)/He ages that have been suggested (e.g. [4,5]). 1. Whitehead, N. & Ditchburn, R. New Zealand Journal of Geology and Geophysics 37, 381-383 (1994). 2. Ota, Y., Omura, A. & Iwata, H. New Zealand Journal of Geology and Geophysics 32, 327-331 (1989). 3. Wilson, C. J. N. et al. Quaternary Science Reviews 26, 1861-1870 (2007). 4. Molloy, C., Shane, P. & Augustinus, P. Geological Society of America Bulletin 121, 1666-1677 (2009). 5

  18. Nucleotide variation and identification of novel blast resistance alleles of Pib by allele mining strategy.

    PubMed

    Ramkumar, G; Madhav, M S; Devi, S J S Rama; Prasad, M S; Babu, V Ravindra

    2015-04-01

    Pib is one of significant rice blast resistant genes, which provides resistance to wide range of isolates of rice blast pathogen, Magnaporthe oryzae. Identification and isolation of novel and beneficial alleles help in crop enhancement. Allele mining is one of the best strategies for dissecting the allelic variations at candidate gene and identification of novel alleles. Hence, in the present study, Pib was analyzed by allele mining strategy, and coding and non-coding (upstream and intron) regions were examined to identify novel Pib alleles. Allelic sequences comparison revealed that nucleotide polymorphisms at coding regions affected the amino acid sequences, while the polymorphism at upstream (non-coding) region affected the motifs arrangements. Pib alleles from resistant landraces, Sercher and Krengosa showed better resistance than Pib donor variety, might be due to acquired mutations, especially at LRR region. The evolutionary distance, Ka/Ks and phylogenetic analyzes also supported these results. Transcription factor binding motif analysis revealed that Pib (Sr) had a unique motif (DPBFCOREDCDC3), while five different motifs differentiated the resistance and susceptible Pib alleles. As the Pib is an inducible gene, the identified differential motifs helps to understand the Pib expression mechanism. The identified novel Pib resistant alleles, which showed high resistance to the rice blast, can be used directly in blast resistance breeding program as alternative Pib resistant sources.

  19. Vanishing GC-rich isochores in mammalian genomes.

    PubMed Central

    Duret, Laurent; Semon, Marie; Piganeau, Gwenaël; Mouchiroud, Dominique; Galtier, Nicolas

    2002-01-01

    To understand the origin and evolution of isochores-the peculiar spatial distribution of GC content within mammalian genomes-we analyzed the synonymous substitution pattern in coding sequences from closely related species in different mammalian orders. In primate and cetartiodactyls, GC-rich genes are undergoing a large excess of GC --> AT substitutions over AT --> GC substitutions: GC-rich isochores are slowly disappearing from the genome of these two mammalian orders. In rodents, our analyses suggest both a decrease in GC content of GC-rich isochores and an increase in GC-poor isochores, but more data will be necessary to assess the significance of this pattern. These observations question the conclusions of previous works that assumed that base composition was at equilibrium. Analysis of allele frequency in human polymorphism data, however, confirmed that in the GC-rich parts of the genome, GC alleles have a higher probability of fixation than AT alleles. This fixation bias appears not strong enough to overcome the large excess of GC --> AT mutations. Thus, whatever the evolutionary force (neutral or selective) at the origin of GC-rich isochores, this force is no longer effective in mammals. We propose a model based on the biased gene conversion hypothesis that accounts for the origin of GC-rich isochores in the ancestral amniote genome and for their decline in present-day mammals. PMID:12524353

  20. Comparison of HLA allelic imputation programs.

    PubMed

    Karnes, Jason H; Shaffer, Christian M; Bastarache, Lisa; Gaudieri, Silvana; Glazer, Andrew M; Steiner, Heidi E; Mosley, Jonathan D; Mallal, Simon; Denny, Joshua C; Phillips, Elizabeth J; Roden, Dan M

    2017-01-01

    Imputation of human leukocyte antigen (HLA) alleles from SNP-level data is attractive due to importance of HLA alleles in human disease, widespread availability of genome-wide association study (GWAS) data, and expertise required for HLA sequencing. However, comprehensive evaluations of HLA imputations programs are limited. We compared HLA imputation results of HIBAG, SNP2HLA, and HLA*IMP:02 to sequenced HLA alleles in 3,265 samples from BioVU, a de-identified electronic health record database coupled to a DNA biorepository. We performed four-digit HLA sequencing for HLA-A, -B, -C, -DRB1, -DPB1, and -DQB1 using long-read 454 FLX sequencing. All samples were genotyped using both the Illumina HumanExome BeadChip platform and a GWAS platform. Call rates and concordance rates were compared by platform, frequency of allele, and race/ethnicity. Overall concordance rates were similar between programs in European Americans (EA) (0.975 [SNP2HLA]; 0.939 [HLA*IMP:02]; 0.976 [HIBAG]). SNP2HLA provided a significant advantage in terms of call rate and the number of alleles imputed. Concordance rates were lower overall for African Americans (AAs). These observations were consistent when accuracy was compared across HLA loci. All imputation programs performed similarly for low frequency HLA alleles. Higher concordance rates were observed when HLA alleles were imputed from GWAS platforms versus the HumanExome BeadChip, suggesting that high genomic coverage is preferred as input for HLA allelic imputation. These findings provide guidance on the best use of HLA imputation methods and elucidate their limitations.

  1. Comparison of HLA allelic imputation programs

    PubMed Central

    Shaffer, Christian M.; Bastarache, Lisa; Gaudieri, Silvana; Glazer, Andrew M.; Steiner, Heidi E.; Mosley, Jonathan D.; Mallal, Simon; Denny, Joshua C.; Phillips, Elizabeth J.; Roden, Dan M.

    2017-01-01

    Imputation of human leukocyte antigen (HLA) alleles from SNP-level data is attractive due to importance of HLA alleles in human disease, widespread availability of genome-wide association study (GWAS) data, and expertise required for HLA sequencing. However, comprehensive evaluations of HLA imputations programs are limited. We compared HLA imputation results of HIBAG, SNP2HLA, and HLA*IMP:02 to sequenced HLA alleles in 3,265 samples from BioVU, a de-identified electronic health record database coupled to a DNA biorepository. We performed four-digit HLA sequencing for HLA-A, -B, -C, -DRB1, -DPB1, and -DQB1 using long-read 454 FLX sequencing. All samples were genotyped using both the Illumina HumanExome BeadChip platform and a GWAS platform. Call rates and concordance rates were compared by platform, frequency of allele, and race/ethnicity. Overall concordance rates were similar between programs in European Americans (EA) (0.975 [SNP2HLA]; 0.939 [HLA*IMP:02]; 0.976 [HIBAG]). SNP2HLA provided a significant advantage in terms of call rate and the number of alleles imputed. Concordance rates were lower overall for African Americans (AAs). These observations were consistent when accuracy was compared across HLA loci. All imputation programs performed similarly for low frequency HLA alleles. Higher concordance rates were observed when HLA alleles were imputed from GWAS platforms versus the HumanExome BeadChip, suggesting that high genomic coverage is preferred as input for HLA allelic imputation. These findings provide guidance on the best use of HLA imputation methods and elucidate their limitations. PMID:28207879

  2. Stability of Ar(H2)2 to 358 GPa.

    PubMed

    Ji, Cheng; Goncharov, Alexander F; Shukla, Vivekanand; Jena, Naresh K; Popov, Dmitry; Li, Bing; Wang, Junyue; Meng, Yue; Prakapenka, Vitali B; Smith, Jesse S; Ahuja, Rajeev; Yang, Wenge; Mao, Ho-Kwang

    2017-04-04

    "Chemical precompression" through introducing impurity atoms into hydrogen has been proposed as a method to facilitate metallization of hydrogen under external pressure. Here we selected Ar(H2)2, a hydrogen-rich compound with molecular hydrogen, to explore the effect of "doping" on the intermolecular interaction of H2 molecules and metallization at ultrahigh pressure. Ar(H2)2 was studied experimentally by synchrotron X-ray diffraction to 265 GPa, by Raman and optical absorption spectroscopy to 358 GPa, and theoretically using the density-functional theory. Our measurements of the optical bandgap and the vibron frequency show that Ar(H2)2 retains 2-eV bandgap and H2 molecular units up to 358 GPa. This is attributed to reduced intermolecular interactions between H2 molecules in Ar(H2)2 compared with that in solid H2 A splitting of the molecular vibron mode above 216 GPa suggests an orientational ordering transition, which is not accompanied by a change in lattice symmetry. The experimental and theoretical equations of state of Ar(H2)2 provide direct insight into the structure and bonding of this hydrogen-rich system, suggesting a negative chemical pressure on H2 molecules brought about by doping of Ar.

  3. Xenocrysts and antecrysts and their effect on the precision of 40Ar/39Ar dates of explosive volcanic eruption

    NASA Astrophysics Data System (ADS)

    Smith, V.; Mark, D.; Blockley, S.; Weh, A.

    2010-12-01

    Evolved melts that fuel large explosive eruptions encounter, and are often generated through melting, crystal-rich parts of the magmatic system that fed previous eruptions. This results in many antecrysts being incorporated into the magma prior to eruption. In addition, many xenocrysts are entrained during eruption through conduit excavation. Combining all these crystal populations produces 40Ar/39Ar dates with wide-ranges, such as those that are often reported in the literature. In order to gain very precise dates of volcanic events it is thus necessary to assess whether antecrysts and xenocrysts effect the precision of the dates, and establish ways to reduce these components. Here we use the deposits of the ~11 ka Ulleung-Oki eruption from the alkaline volcanic island of Ulleung, situated 130 km east of the Korean peninsula. The eruption deposits are widely dispersed and found in the Suigetsu lake sequence from central Japan. A precise date of the tephra would help with construction of the terrestrial radiocarbon calibration curve that spans back to the limit of radiocarbon dating (~50 ka). The new calibration model is currently being constructed using varve chronology (annual layer counting) and >600 14C determinations of terrestrial macrofossils*. However, the annual layers stop shortly after the 2 cm-thick Ulleung-Oki tephra. Precise dates of this volcanic event using a method that is independent of radiocarbon dating, would help validate the chronology of the core, and test the validity of the radiocarbon calibration curve. The tephra in the core has been correlated to proximal deposits using major and trace element composition (determined using an electron microprobe and LA-ICPMS) of the glass shards that comprise the distal ash. The proximal Ulleung-Oki eruption deposits are sandine-rich with crystals that range from ~80 microns to a few millimetres in size. These are likely to be a mixture of phenocrysts, antecrysts and xenocrysts. In order to get a very

  4. Allele Workbench: transcriptome pipeline and interactive graphics for allele-specific expression.

    PubMed

    Soderlund, Carol A; Nelson, William M; Goff, Stephen A

    2014-01-01

    Sequencing the transcriptome can answer various questions such as determining the transcripts expressed in a given species for a specific tissue or condition, evaluating differential expression, discovering variants, and evaluating allele-specific expression. Differential expression evaluates the expression differences between different strains, tissues, and conditions. Allele-specific expression evaluates expression differences between parental alleles. Both differential expression and allele-specific expression have been studied for heterosis (hybrid vigor), where the hybrid has improved performance over the parents for one or more traits. The Allele Workbench software was developed for a heterosis study that evaluated allele-specific expression for a mouse F1 hybrid using libraries from multiple tissues with biological replicates. This software has been made into a distributable package, which includes a pipeline, a Java interface to build the database, and a Java interface for query and display of the results. The required input is a reference genome, annotation file, and one or more RNA-Seq libraries with optional replicates. It evaluates allelic imbalance at the SNP and transcript level and flags transcripts with significant opposite directional allele-specific expression. The Java interface allows the user to view data from libraries, replicates, genes, transcripts, exons, and variants, including queries on allele imbalance for selected libraries. To determine the impact of allele-specific SNPs on protein folding, variants are annotated with their effect (e.g., missense), and the parental protein sequences may be exported for protein folding analysis. The Allele Workbench processing results in transcript files and read counts that can be used as input to the previously published Transcriptome Computational Workbench, which has a new algorithm for determining a trimmed set of gene ontology terms. The software with demo files is available from https://code.google.com/p/allele

  5. Ten novel HLA-DRB1 alleles and one novel DRB3 allele.

    PubMed

    Lazaro, A M; Steiner, N K; Moraes, M E; Moraes, J R; Ng, J; Hartzman, R J; Hurley, C K

    2005-10-01

    Ten novel HLA-DRB1 and one DRB3 alleles are described. Eight of the variants are single-nucleotide substitutions, four resulting in an amino acid change (DRB1*1145, *1148, *0828 and *1514) and four with silent substitutions (DRB1*040504, *130103, *160502 and DRB3*020204). Two alleles differ by two nucleotide changes altering one (DRB1*1447 and *1361) amino acid and one allele alters three nucleotides and two amino acids.

  6. Abnormal segregation of alleles in CEPH pedigree DNAs arising from allele loss in lymphoblastoid DNA

    SciTech Connect

    Royle, N.J.; Armour, J.A.L.; Crosier, M.; Jeffreys, A.J. )

    1993-01-01

    Somatic events that result in the reduction to hemior homozygosity at all loci affected by the event have been identified in lymphoblastoid DNA from mothers of two CEPH families. Using suitably informative probes, the allele deficiencies were detected by the abnormal transmission of alleles from grandparents to grandchildren, with the apparent absence of the alleles from the parent. Undetected somatic deficiencies in family DNAs could result in misscoring of recombination events and consequently introduce errors into linkage analysis. 15 refs., 2 figs.

  7. Ten Novel HLA-DRB1 Alleles and One Novel DRB3 Allele

    DTIC Science & Technology

    2006-05-31

    BRIEF COMMUNICATION Ten novel HLA-DRB1 alleles and one novel DRB3 allele A. M. Lazaro1, N. K. Steiner1, M. E. Moraes2, J. R. Moraes2, J. Ng1, R. J...accepted for publication 31 May 2005 doi: 10.1111/j.1399-0039.2005.00459.x Abstract Ten novel HLA-DRB1 and one DRB3 alleles are described. Eight of the...substitutions (DRB1*040504, *130103, *160502 and DRB3 *020204). Two alleles differ by two nucleotide changes altering one (DRB1*1447 and *1361) amino acid and

  8. Viscosity and phase separations of binary CO-He and CO-Ar mixtures

    NASA Astrophysics Data System (ADS)

    Rademacher, N.; Bayarjargal, L.; Morgenroth, W.; Ciezak-Jenkins, J. A.; Winkler, B.

    2015-01-01

    Binary mixtures of 10 and 25 vol% CO in He and 10 vol% CO in Ar have been studied at high pressures and ambient temperature in diamond anvil cells. Phase separations were observed at 5.7(3) GPa, 3.6(2) GPa and 1.6(1) GPa. Earlier studies of ?-He mixtures of comparable concentrations revealed phase separations at significantly larger pressures, while ?-Ar mixtures separate at pressures comparable to those observed in the CO-Ar system here. The viscosity of a CO-rich fluid phase was determined by measuring the velocities of rising He bubbles. After corrections for the influence of the finite container size and of remaining helium in CO, the viscosity of the CO-rich fluid at 3.8(1) GPa was ≈3(1) mPa s, similar to what would be expected for isoelectronic liquid ? under the same conditions.

  9. Evidence of synmagmatic foliation in the Selawik Hills, NW Alaska, based on [sup 40]Ar/[sup 39]Ar age determinations

    SciTech Connect

    Solie, D.N. ); Layer, P.W. . Geophysical Inst.)

    1993-04-01

    Based on [sup 40]Ar/[sup 39]Ar plateau ages from various rock units in the Selawik Hills plutonic complex, northwestern Alaska, the units were emplaced in the order syenite/monzonite, followed by nepheline syenite and then quartz monzonite. There is no evidence of disturbance of the Ar isotopic system in the dated plutonic minerals, and the ages compare fairly well with previously published K/Ar data. A cooling history of about ten m.y. for the Selawk Hills rocks is suggested, based on comparison of [sup 40]Ar/[sup 39]Ar ages with apatite fission-track data (Murphy and Till, 1992). Comparison of hornblende plateau ages between nonfoliated and foliated syenite indicates that foliated rocks crystallized later than nonfoliated rocks, but within the initial cooling history of the complex. Foliated syenite/monzonite has mineralogy similar to nonfoliated, but with generally higher color index. Foliated textures are distributed throughout the complex, but are more prevalent to the north, proximal to a large (about 2 km[sup 2]) xenolithic metamorphic block which is bounded on the north by an east-west-trending fault. The authors suggest that synmagmatic fault movement acted as a mechanism causing plutonic foliation and resulting in possible loss of late fluid from semicrystallized syenitic magma to form kspar-rich dikes. Foundering of the xenolithic block within the magma may also have contributed to development of foliation. Continued fault movement is indicated by cataclastic deformation along the fault trace.

  10. Interpretation of discordant 40Ar/39Ar age-spectra of mesozoic tholeiites from antarctica

    USGS Publications Warehouse

    Fleck, R.J.; Sutter, J.F.; Elliot, D.H.

    1977-01-01

    Conventional K-Ar ages of tholeiitic basalts of the Ferrar Group in the central Transantarctic Mountains indicate significant loss of radiogenic 40Ar from this unit over much of its outcrop area. Argon loss varies inversely with amount of devitrified matrix in the basalts, which have not been thermally or tectonically disturbed since extrusion. 40Ar/19Ar age-spectra of these tholeiites are generally discordant and indicate significant inhomogeneity in the distribution of radiogenic 40Ar with respect to 39Ar, but are distinctly different from release patterns of thermally disturbed samples. Amounts of argon redistribution vary directly with amounts of devitrification and are reflected in progressive modification of the age spectra. A model of redistribution of radiogenic 40Ar by devitrification of originally glassy matrix is suggested that is consistent with disturbance of the conventional K-Ar systematics as well as the 40Ar/39Ar age-spectra. Samples with substantial redistribution but minor loss of radiogenic argon yield age spectra whose apparent ages decrease from low-temperature to high-temperature steps, similar to those reported for some lunar basalts, breccias, and soils. Modification of all the age spectra is attributed to redistribution of radiogenic 40Ar during progressive devitrification, although 39Ar-recoil effects suggested by Turner and Cadogan (1974) may be a factor in some cases. Where devitrification involves most potassium sites within the basalt, 40Ar/39Ar age-plateaux may be formed that have no geologic significance. ?? 1977.

  11. Metrologically-Calibrated 40Ar Concentrations and Ages of Mineral Standards Used in 40Ar/39Ar Geochronology

    NASA Astrophysics Data System (ADS)

    Morgan, L. E.; Davidheiser-Kroll, B.; Kuiper, K.; Wijbrans, J. R.; Mark, D. F.

    2015-12-01

    In geochronology, isotopic ages are determined from the ratio of parent and daughter nuclide concentrations in minerals. For dating of geological material using the K-Ar system, the simultaneous determination of 40Ar and 40K concentrations on the same aliquot is not possible. Therefore, a widely used variant, the 40Ar/39Ar technique, involves the production of 39Ar from 39K by neutron bombardment and the reliance on indirect natural calibrators of the neutron flux, referred to as "mineral standards." Many mineral standards still in use rely on decades-old determinations of 40Ar concentrations; resulting uncertainties, both systematic and analytical, impede the determination of higher accuracy ages using the K-Ar decay system. We present results for the 40Ar concentrations and ages of mineral standards determined based on a modern gas delivery system (Morgan et al. 2011), which delivers metrologically-traceable amounts of 40Ar and thus allows for the sensitivity calibration of noble gas mass spectrometers.

  12. Allele-specific DNA methylation: beyond imprinting.

    PubMed

    Tycko, Benjamin

    2010-10-15

    Allele-specific DNA methylation (ASM) and allele-specific gene expression (ASE) have long been studied in genomic imprinting and X chromosome inactivation. But these types of allelic asymmetries, along with allele-specific transcription factor binding (ASTF), have turned out to be far more pervasive-affecting many non-imprinted autosomal genes in normal human tissues. ASM, ASE and ASTF have now been mapped genome-wide by microarray-based methods and NextGen sequencing. Multiple studies agree that all three types of allelic asymmetries, as well as the related phenomena of expression and methylation quantitative trait loci, are mostly accounted for by cis-acting regulatory polymorphisms. The precise mechanisms by which this occurs are not yet understood, but there are some testable hypotheses and already a few direct clues. Future challenges include achieving higher resolution maps to locate the epicenters of cis-regulated ASM, using this information to test mechanistic models, and applying genome-wide maps of ASE/ASM/ASTF to pinpoint functional regulatory polymorphisms influencing disease susceptibility.

  13. AlleleSeq: analysis of allele-specific expression and binding in a network framework.

    PubMed

    Rozowsky, Joel; Abyzov, Alexej; Wang, Jing; Alves, Pedro; Raha, Debasish; Harmanci, Arif; Leng, Jing; Bjornson, Robert; Kong, Yong; Kitabayashi, Naoki; Bhardwaj, Nitin; Rubin, Mark; Snyder, Michael; Gerstein, Mark

    2011-08-02

    To study allele-specific expression (ASE) and binding (ASB), that is, differences between the maternally and paternally derived alleles, we have developed a computational pipeline (AlleleSeq). Our pipeline initially constructs a diploid personal genome sequence (and corresponding personalized gene annotation) using genomic sequence variants (SNPs, indels, and structural variants), and then identifies allele-specific events with significant differences in the number of mapped reads between maternal and paternal alleles. There are many technical challenges in the construction and alignment of reads to a personal diploid genome sequence that we address, for example, bias of reads mapping to the reference allele. We have applied AlleleSeq to variation data for NA12878 from the 1000 Genomes Project as well as matched, deeply sequenced RNA-Seq and ChIP-Seq data sets generated for this purpose. In addition to observing fairly widespread allele-specific behavior within individual functional genomic data sets (including results consistent with X-chromosome inactivation), we can study the interaction between ASE and ASB. Furthermore, we investigate the coordination between ASE and ASB from multiple transcription factors events using a regulatory network framework. Correlation analyses and network motifs show mostly coordinated ASB and ASE.

  14. Forensic Loci Allele Database (FLAD): Automatically generated, permanent identifiers for sequenced forensic alleles.

    PubMed

    Van Neste, Christophe; Van Criekinge, Wim; Deforce, Dieter; Van Nieuwerburgh, Filip

    2016-01-01

    It is difficult to predict if and when massively parallel sequencing of forensic STR loci will replace capillary electrophoresis as the new standard technology in forensic genetics. The main benefits of sequencing are increased multiplexing scales and SNP detection. There is not yet a consensus on how sequenced profiles should be reported. We present the Forensic Loci Allele Database (FLAD) service, made freely available on http://forensic.ugent.be/FLAD/. It offers permanent identifiers for sequenced forensic alleles (STR or SNP) and their microvariants for use in forensic allele nomenclature. Analogous to Genbank, its aim is to provide permanent identifiers for forensically relevant allele sequences. Researchers that are developing forensic sequencing kits or are performing population studies, can register on http://forensic.ugent.be/FLAD/ and add loci and allele sequences with a short and simple application interface (API).

  15. ACTH Action on StAR Biology.

    PubMed

    Clark, Barbara J

    2016-01-01

    Adrenocorticotropin hormone (ACTH) produced by the anterior pituitary stimulates glucocorticoid synthesis by the adrenal cortex. The first step in glucocorticoid synthesis is the delivery of cholesterol to the mitochondrial matrix where the first enzymatic reaction in the steroid hormone biosynthetic pathway occurs. A key response of adrenal cells to ACTH is activation of the cAMP-protein kinase A (PKA) signaling pathway. PKA activation results in an acute increase in expression and function of the Steroidogenic Acute Regulatory protein (StAR). StAR plays an essential role in steroidogenesis- it controls the hormone-dependent movement of cholesterol across the mitochondrial membranes. Currently StAR's mechanism of action remains a major unanswered question in the field. However, some insight may be gained from understanding the mechanism(s) controlling the PKA-dependent phosphorylation of StAR at S194/195 (mouse/human StAR), a modification that is required for function. This mini-review provides a background on StAR's biology with a focus on StAR phosphorylation. The model for StAR translation and phosphorylation at the outer mitochondrial membrane, the location for StAR function, is presented to highlight a unifying theme emerging from diverse studies.

  16. ACTH Action on StAR Biology

    PubMed Central

    Clark, Barbara J.

    2016-01-01

    Adrenocorticotropin hormone (ACTH) produced by the anterior pituitary stimulates glucocorticoid synthesis by the adrenal cortex. The first step in glucocorticoid synthesis is the delivery of cholesterol to the mitochondrial matrix where the first enzymatic reaction in the steroid hormone biosynthetic pathway occurs. A key response of adrenal cells to ACTH is activation of the cAMP-protein kinase A (PKA) signaling pathway. PKA activation results in an acute increase in expression and function of the Steroidogenic Acute Regulatory protein (StAR). StAR plays an essential role in steroidogenesis- it controls the hormone-dependent movement of cholesterol across the mitochondrial membranes. Currently StAR's mechanism of action remains a major unanswered question in the field. However, some insight may be gained from understanding the mechanism(s) controlling the PKA-dependent phosphorylation of StAR at S194/195 (mouse/human StAR), a modification that is required for function. This mini-review provides a background on StAR's biology with a focus on StAR phosphorylation. The model for StAR translation and phosphorylation at the outer mitochondrial membrane, the location for StAR function, is presented to highlight a unifying theme emerging from diverse studies. PMID:27999527

  17. Androgen receptor (AR) in cardiovascular diseases.

    PubMed

    Huang, Chiung-Kuei; Lee, Soo Ok; Chang, Eugene; Pang, Haiyan; Chang, Chawnshang

    2016-04-01

    Cardiovascular diseases (CVDs) are still the highest leading cause of death worldwide. Several risk factors have been linked to CVDs, including smoking, diabetes, hyperlipidemia, and gender among others. Sex hormones, especially the androgen and its receptor, androgen receptor (AR), have been linked to many diseases with a clear gender difference. Here, we summarize the effects of androgen/AR on CVDs, including hypertension, stroke, atherosclerosis, abdominal aortic aneurysm (AAA), myocardial hypertrophy, and heart failure, as well as the metabolic syndrome/diabetes and their impacts on CVDs. Androgen/AR signaling exacerbates hypertension, and anti-androgens may suppress hypertension. Androgen/AR signaling plays dual roles in strokes, depending on different kinds of factors; however, generally males have a higher incidence of strokes than females. Androgen and AR differentially modulate atherosclerosis. Androgen deficiency causes elevated lipid accumulation to enhance atherosclerosis; however, targeting AR in selective cells without altering serum androgen levels would suppress atherosclerosis progression. Androgen/AR signaling is crucial in AAA development and progression, and targeting androgen/AR profoundly restricts AAA progression. Men have increased cardiac hypertrophy compared with age-matched women that may be due to androgens. Finally, androgen/AR plays important roles in contributing to obesity and insulin/leptin resistance to increase the metabolic syndrome.

  18. 40Ar/39Ar Interlaboratory Calibration into the Holocene.

    NASA Astrophysics Data System (ADS)

    Heizler, M. T.; Jicha, B.; Koppers, A. A. P.; Miggins, D. P.

    2015-12-01

    Advances in 40Ar/39Ar analytical precision for very young rocks requires collaborative efforts amongst argon geochronology labs to demonstrate age reproducibility commensurate with high precision. NM Tech (NMT), the University of Wisconsin (UW) and Oregon State University (OSU) have each dated Quaternary flux monitor standard AC-2 sanidine (~1.185 Ma), a blind sanidine described as being 50-100 ka (BS) and sanidine from the Qixiangshan (QIX) flow (~10 ka), Changbaishan volcano, China. The samples were irradiated in a single package with FC-2 sanidine (28.201 Ma) as the flux monitor and the irradiated material was distributed amongst the labs. Heizler was present during analysis at both OSU and UW and Jicha attended OSU during analysis. Physical presence was key towards gaining understanding of individual protocols and prompted valuable discussions. Analyses were carried out on single crystals using total fusion and/or step heating approaches. Age agreement was achieved within 2s uncertainty that ranged between (0.03-0.3%, 0.13-0.37% and 1.8-2.6%) for AC-2, BS and QIX, respectively. Each lab found AC-2 to vary somewhat beyond a normal distribution and to yield an age relative to FC-2 of ~1.185 Ma that is ~1.3% (~5-10 sigma) lower than some published estimates. A key cause of the variation between this study and previous results may be variable gas pressure equilibration times between extraction line and mass spectrometer coupled with variable choices to estimate time zero by other laboratories. The majority of our efforts concentrated on the QIX sanidine where prior data obtained by our labs revealed a factor of two spread in age (~11 and 23 ka) based on experiments carried out by total fusion and bulk incremental heating. By conducting single crystal age spectrum analysis we were able to mitigate effects of melt inclusion hosted excess argon and xenocrystic contamination towards obtaining analytical agreement with apparent ages near 10 ka. However, philosophical

  19. Transformation of QTL genotypic effects to allelic effects

    PubMed Central

    Nagamine, Yoshitaka

    2005-01-01

    The genotypic and allelic effect models are equivalent in terms of QTL detection in a simple additive model, but the QTL allelic model has the advantage of providing direct information for marker-assisted selection. However, the allelic matrix is four times as large as the genotypic IBD matrix, causing computational problems, especially in genome scans examining multiple positions. Transformation from genotypic to allelic effects, after estimating the genotypic effects with a smaller IBD matrix, can solve this problem. Although the validity of transformation from genotypic to allelic effects has been disputed, this work proves that transformation can successfully yield unique allelic effects when genotypic and allelic IBD matrixes exist. PMID:16093016

  20. First-principles calibration of 40Ar/39Ar mineral standards and complete extraction of 40Ar* from sanidine

    NASA Astrophysics Data System (ADS)

    Morgan, L. E.; Kuiper, K.; Mark, D.; Postma, O.; Villa, I. M.; Wijbrans, J. R.

    2010-12-01

    40Ar/39Ar geochronology relies on comparing argon isotopic data for unknowns to those for knowns. Mineral standards used as neutron fluence monitors must be dated by the K-Ar method (or at least referenced to a mineral of known K-Ar age). The commonly used age of 28.02 ± 0.28 Ma for the Fish Canyon sanidine (FCs) (Renne et al., 1998) is based upon measurements of radiogenic 40Ar in GA1550 biotite (McDougall and Roksandic, 1974), but underlying full data were not published (these measurements were never intended for use as an international standard), so uncertainties are difficult to assess. Recent developments by Kuiper et al. (2008) and Renne et al. (2010) are limited by their reliance on the accuracy of other systems. Modern technology should allow for more precise and accurate calibration of primary K-Ar and 40Ar/39Ar standards. From the ideal gas law, the number of moles of 40Ar in a system can be calculated from measurements of pressure, volume, and temperature. Thus we have designed and are proceeding to build a pipette system to introduce well-determined amounts of 40Ar into noble gas extraction lines and mass spectrometers. This system relies on components with calibrations traceable to SI unit prototypes, including a diaphragm pressure gauge (MKS Instruments), thermocouples, and a “slug” of an accurately determined volume to be inserted into the reservoir for volume determinations of the reservoir and pipette. The system will be renewable, with a lifetime of ca. 1 month for gas in the reservoir, and portable, to permit interlaboratory calibrations. The quantitative extraction of 40Ar* from the mineral standard is of highest importance; for sanidine standards this is complicated by high melt viscosity during heating. Experiments adding basaltic “zero age glass” (ZAG) to decrease melt viscosity are underway. This has previously been explored by McDowell (1983) with a resistance furnace, but has not been quantitatively addressed with laser heating

  1. Re-Evaluation of Ar-39 - Ar-40 Ages for Apollo Lunar Rocks 15415 and 60015

    NASA Technical Reports Server (NTRS)

    Park, J.; Nyquist, L. E.; Bogard, D. D.; Garrison, D. H.; Shih, C.-Y.

    2010-01-01

    We re-analyzed 39Ar-40Ar ages of Apollo lunar highland samples 15415 and 60015, two ferroan anorthosites analyzed previously in the 1970 s, with a more detailed approach and with revised decay constants. From these samples we carefully prepared 100-200 mesh mineral separates for analysis at the Noble Gas Laboratory at NASA-Johnson Space Center. The Ar-39-Ar-40 age spectra for 15415 yielded an age of 3851 +/- 38 Ma with 33-99% of Ar39 release, roughly in agreement with previously reported Ar-Ar ages. For 60015, we obtained an age of 3584 +/- 152 Ma in 23-98% of Ar39 release, also in agreement with previously reported Ar-Ar ages of approximately 3.5 Ga. Highland anorthosites like these are believed by many to be the original crust of the moon, formed by plagioclase floatation atop a magma ocean, however the Ar-Ar ages of 15415 and 60015 are considerably younger than lunar crust formation. By contrast, recently recovered lunar anorthosites such as Dhofar 489, Dhofar 908, and Yamato 86032 yield older Ar-Ar ages, up to 4.35 Ga, much closer to time of formation of the lunar crust. It follows that the Ar-Ar ages of the Apollo samples must have been reset by secondary heating, and that this heating affected highland anorthosites at both the Apollo 15 and Apollo 16 landing sites but did not affect lunar highland meteorites. One obvious consideration is that while the Apollo samples were collected from the near side of the moon, these lunar meteorites are thought to have originated from the lunar far side

  2. Ion kinetics in Ar/H2 cold plasmas: the relevance of ArH+

    PubMed Central

    Jiménez-Redondo, Miguel; Cueto, Maite; Doménech, José Luis; Tanarro, Isabel; Herrero, Víctor J.

    2015-01-01

    The recent discovery of ArH+ in the interstellar medium has awakened the interest in the chemistry of this ion. In this work, the ion-molecule kinetics of cold plasmas of Ar/H2 is investigated in glow discharges spanning the whole range of [H2]/([H2]+[Ar]) proportions for two pressures, 1.5 and 8 Pa. Ion concentrations are determined by mass spectrometry, and electron temperatures and densities, with Langmuir probes. A kinetic model is used for the interpretation of the results. The selection of experimental conditions evinces relevant changes with plasma pressure in the ion distributions dependence with the H2 fraction, particularly for the major ions: Ar+, ArH+ and H3+. At 1.5 Pa, ArH+ prevails for a wide interval of H2 fractions: 0.3<[H2]/([H2]+[Ar])<0.7. Nevertheless, a pronounced displacement of the ArH+ maximum towards the lowest H2 fractions is observed at 8 Pa, in detriment of Ar+, which becomes restricted to very small [H2]/([H2]+[Ar]) ratios, whereas H3+ becomes dominant for all [H2]/([H2]+[Ar]) > 0.1. The analysis of the data with the kinetic model allows the identification of the sources and sinks of the major ions over the whole range of experimental conditions sampled. Two key factors turn out to be responsible for the different ion distributions observed: the electron temperature, which determines the rate of Ar+ formation and thus of ArH+, and the equilibrium ArH+ + H2 ⇄ H3+ + Ar, which can be strongly dependent of the degree of vibrational excitation of H3+. The results are discussed and compared with previously published data on other Ar/H2 plasmas. PMID:26702354

  3. 40Ar/ 39Ar dating of latest Pleistocene (41 ka) marine tephra in the Mediterranean Sea: implications for global climate records

    NASA Astrophysics Data System (ADS)

    Ton-That, Thao; Singer, Brad; Paterne, Martine

    2001-01-01

    Fifty-one 40Ar/ 39Ar laser heating analyses of sanidine crystals in the C-13 tephra layer, recovered out of a piston core raised from 3000 m depth in the Tyrrhenian Sea, yielded apparent ages between 25 and 112 ka. Twenty-four of these measurements define an age probability maximum and generate an isochron of 41.1±2.1 ka (2σ) with a 40Ar/ 36Ar intercept of 288±21 that is indistinguishable from the modern atmosphere. However, the entire population is skewed toward older apparent ages with smaller peaks at 48 ka, 55 ka, 67 ka, and 110 ka. The composition of glass shards in the C-13 tephra overlaps that of the SiO 2-rich phase of the 150 km 3 Campanian Ignimbrite which erupted from the Campi Flegrei caldera 130 km northwest of the core site. Although the 41.1±2.1 ka isochron is ˜15% older than K-Ar and 14C ages for the Campanian Ignimbrite, it is indistinguishable from recent 40Ar/ 39Ar age determinations. The Campanian Ignimbrite eruptions were also chemically similar to, and correlated with, the Y-5 ash layer - the most voluminous and widely dispersed late Pleistocene tephra in the Mediterranean region. The age of the Y-5 layer was constrained originally at 38.0±2.5 ka on the basis of astronomical dating of O-isotope stages. The 40Ar/ 39Ar ages, astronomical dating, plus chemical similarities permit correlation of the C-13 tephra layer with both the Campanian Ignimbrite and the Y-5 tephra layer. The older ages preserved in the C-13 tephra layer may reflect xenocrysts incorporated during the explosive eruption accompanying collapse of the Campi Flegrei caldera 41 ka. The C-13 tephra layer is correlated with a 10Be peak in an adjacent marine core, O-isotope stage 3.12, and immediately preceded a cooling episode corresponding to Heinrich event 4, thus the age of these features is constrained by radioisotope dating. The 41 ka peak in 10Be deposition is a global phenomenon whose age matches that of the Laschamp geomagnetic excursion. Thus, our results provide a new

  4. 244-AR Vault Interim Stabilization Project Plan

    SciTech Connect

    LANEY, T.

    2000-03-24

    The 244-AR Vault Facility, constructed between 1966 and 1968, was designed to provide lag storage and treatment for the Plutonium-Uranium Extraction Facility (PUREX) tank farm sludges. Tank farm personnel transferred the waste from the 244-AR Vault Facility to B Plant for recovery of cesium and strontium. B Plant personnel then transferred the treatment residuals back to the tank farms for storage of the sludge and liquids. The last process operations, which transferred waste supporting the cesium/strontium recovery mission, occurred in April 1978. After the final transfer in 1978, the 244-AR facility underwent a cleanout. However, 2,271 L (600 gal) of sludge were left in Tank 004AR from an earlier transfer from Tank 241-AX-104. When the cleanout was completed, the facility was placed in a standby status. The sludge had been transferred to Tank 004AR to support Pacific Northwest National Laboratory [PNNL] vitrification work. Documentation of waste transfers suggests that a portion of the sludge may have been moved from Tank 004AR to Tank 002AR in preparation for transfer back to the AX Tank Farm; however, quantities of the sludge that were moved to Tank 002AR from that transfer must be estimated.

  5. USDA/ARS Organic Production Research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For much of its history, USDA/ARS had little to do with research on organic agriculture, however research in organic systems has made considerable gains at the agency over the past decade. In the 1980's and 1990's, as the organic food industry was taking off, ARS researchers who wanted to serve orga...

  6. Estimating the probability of allelic drop-out of STR alleles in forensic genetics.

    PubMed

    Tvedebrink, Torben; Eriksen, Poul Svante; Mogensen, Helle Smidt; Morling, Niels

    2009-09-01

    In crime cases with available DNA evidence, the amount of DNA is often sparse due to the setting of the crime. In such cases, allelic drop-out of one or more true alleles in STR typing is possible. We present a statistical model for estimating the per locus and overall probability of allelic drop-out using the results of all STR loci in the case sample as reference. The methodology of logistic regression is appropriate for this analysis, and we demonstrate how to incorporate this in a forensic genetic framework.

  7. The B AB AR detector

    NASA Astrophysics Data System (ADS)

    Aubert, B.; Bazan, A.; Boucham, A.; Boutigny, D.; De Bonis, I.; Favier, J.; Gaillard, J.-M.; Jeremie, A.; Karyotakis, Y.; Le Flour, T.; Lees, J. P.; Lieunard, S.; Petitpas, P.; Robbe, P.; Tisserand, V.; Zachariadou, K.; Palano, A.; Chen, G. P.; Chen, J. C.; Qi, N. D.; Rong, G.; Wang, P.; Zhu, Y. S.; Eigen, G.; Reinertsen, P. L.; Stugu, B.; Abbott, B.; Abrams, G. S.; Amerman, L.; Borgland, A. W.; Breon, A. B.; Brown, D. N.; Button-Shafer, J.; Clark, A. R.; Dardin, S.; Day, C.; Dow, S. F.; Fan, Q.; Gaponenko, I.; Gill, M. S.; Goozen, F. R.; Gowdy, S. J.; Gritsan, A.; Groysman, Y.; Hernikl, C.; Jacobsen, R. G.; Jared, R. C.; Kadel, R. W.; Kadyk, J.; Karcher, A.; Kerth, L. T.; Kipnis, I.; Kluth, S.; Kral, J. F.; Lafever, R.; LeClerc, C.; Levi, M. E.; Lewis, S. A.; Lionberger, C.; Liu, T.; Long, M.; Luo, L.; Lynch, G.; Luft, P.; Mandelli, E.; Marino, M.; Marks, K.; Matuk, C.; Meyer, A. B.; Minor, R.; Mokhtarani, A.; Momayezi, M.; Nyman, M.; Oddone, P. J.; Ohnemus, J.; Oshatz, D.; Patton, S.; Pedrali-Noy, M.; Perazzo, A.; Peters, C.; Pope, W.; Pripstein, M.; Quarrie, D. R.; Rasson, J. E.; Roe, N. A.; Romosan, A.; Ronan, M. T.; Shelkov, V. G.; Stone, R.; Strother, P. D.; Telnov, A. V.; von der Lippe, H.; Weber, T. F.; Wenzel, W. A.; Zizka, G.; Bright-Thomas, P. G.; Hawkes, C. M.; Kirk, A.; Knowles, D. J.; O'Neale, S. W.; Watson, A. T.; Watson, N. K.; Deppermann, T.; Koch, H.; Krug, J.; Kunze, M.; Lewandowski, B.; Peters, K.; Schmuecker, H.; Steinke, M.; Andress, J. C.; Barlow, N. R.; Bhimji, W.; Chevalier, N.; Clark, P. J.; Cottingham, W. N.; De Groot, N.; Dyce, N.; Foster, B.; Mass, A.; McFall, J. D.; Wallom, D.; Wilson, F. F.; Abe, K.; Hearty, C.; McKenna, J. A.; Thiessen, D.; Camanzi, B.; Harrison, T. J.; McKemey, A. K.; Tinslay, J.; Antohin, E. I.; Blinov, V. E.; Bukin, A. D.; Bukin, D. A.; Buzykaev, A. R.; Dubrovin, M. S.; Golubev, V. B.; Ivanchenko, V. N.; Kolachev, G. M.; Korol, A. A.; Kravchenko, E. A.; Mikhailov, S. F.; Onuchin, A. P.; Salnikov, A. A.; Serednyakov, S. I.; Skovpen, Yu. I.; Telnov, V. I.; Yushkov, A. N.; Booth, J.; Lankford, A. J.; Mandelkern, M.; Pier, S.; Stoker, D. P.; Zioulas, G.; Ahsan, A.; Arisaka, K.; Buchanan, C.; Chun, S.; Faccini, R.; MacFarlane, D. B.; Prell, S. A.; Rahatlou, Sh.; Raven, G.; Sharma, V.; Burke, S.; Callahan, D.; Campagnari, C.; Dahmes, B.; Hale, D.; Hart, P. A.; Kuznetsova, N.; Kyre, S.; Levy, S. L.; Long, O.; Lu, A.; May, J.; Richman, J. D.; Verkerke, W.; Witherell, M.; Yellin, S.; Beringer, J.; DeWitt, J.; Dorfan, D. E.; Eisner, A. M.; Frey, A.; Grillo, A. A.; Grothe, M.; Heusch, C. A.; Johnson, R. P.; Kroeger, W.; Lockman, W. S.; Pulliam, T.; Rowe, W.; Sadrozinski, H.; Schalk, T.; Schmitz, R. E.; Schumm, B. A.; Seiden, A.; Spencer, E. N.; Turri, M.; Walkowiak, W.; Wilder, M.; Williams, D. C.; Chen, E.; Dubois-Felsmann, G. P.; Dvoretskii, A.; Hanson, J. E.; Hitlin, D. G.; Kolomensky, Yu. G.; Metzler, S.; Oyang, J.; Porter, F. C.; Ryd, A.; Samuel, A.; Weaver, M.; Yang, S.; Zhu, R. Y.; Devmal, S.; Geld, T. L.; Jayatilleke, S.; Jayatilleke, S. M.; Mancinelli, G.; Meadows, B. T.; Sokoloff, M. D.; Bloom, P.; Broomer, B.; Erdos, E.; Fahey, S.; Ford, W. T.; Gaede, F.; van Hoek, W. C.; Johnson, D. R.; Michael, A. K.; Nauenberg, U.; Olivas, A.; Park, H.; Rankin, P.; Roy, J.; Sen, S.; Smith, J. G.; Wagner, D. L.; Blouw, J.; Harton, J. L.; Krishnamurthy, M.; Soffer, A.; Toki, W. H.; Warner, D. W.; Wilson, R. J.; Zhang, J.; Brandt, T.; Brose, J.; Dahlinger, G.; Dickopp, M.; Dubitzky, R. S.; Eckstein, P.; Futterschneider, H.; Kocian, M. L.; Krause, R.; Müller-Pfefferkorn, R.; Schubert, K. R.; Schwierz, R.; Spaan, B.; Wilden, L.; Behr, L.; Bernard, D.; Bonneaud, G. R.; Brochard, F.; Cohen-Tanugi, J.; Ferrag, S.; Fouque, G.; Gastaldi, F.; Matricon, P.; Mora de Freitas, P.; Renard, C.; Roussot, E.; T'Jampens, S.; Thiebaux, C.; Vasileiadis, G.; Verderi, M.; Anjomshoaa, A.; Bernet, R.; Di Lodovico, F.; Muheim, F.; Playfer, S.; Swain, J. E.; Falbo, M.; Bozzi, C.; Dittongo, S.; Folegani, M.; Piemontese, L.; Ramusino, A. C.; Treadwell, E.; Anulli, F.; Baldini-Ferroli, R.; Calcaterra, A.; de Sangro, R.; Falciai, D.; Finocchiaro, G.; Patteri, P.; Peruzzi, I. M.; Piccolo, M.; Xie, Y.; Zallo, A.; Bagnasco, S.; Buzzo, A.; Contri, R.; Crosetti, G.; Fabbricatore, P.; Farinon, S.; Lo Vetere, M.; Macri, M.; Minutoli, S.; Monge, M. R.; Musenich, R.; Pallavicini, M.; Parodi, R.; Passaggio, S.; Pastore, F. C.; Patrignani, C.; Pia, M. G.; Priano, C.; Robutti, E.; Santroni, A.; Bartoldus, R.; Dignan, T.; Hamilton, R.; Mallik, U.; Cochran, J.; Crawley, H. B.; Fischer, P. A.; Lamsa, J.; McKay, R.; Meyer, W. T.; Rosenberg, E. I.; Albert, J. N.; Beigbeder, C.; Benkebil, M.; Breton, D.; Cizeron, R.; Du, S.; Grosdidier, G.; Hast, C.; Höcker, A.; Lacker, H. M.; LePeltier, V.; Lutz, A. M.; Plaszczynski, S.; Schune, M. H.; Trincaz-Duvoid, S.; Truong, K.; Valassi, A.; Wormser, G.; Alford, O.; Behne, D.; Bionta, R. M.; Bowman, J.; Brigljević, V.; Brooks, A.; Dacosta, V. A.; Fackler, O.; Fujino, D.; Harper, M.; Lange, D. J.; Mugge, M.; O'Connor, T. G.; Olson, H.; Ott, L.; Parker, E.; Pedrotti, B.; Roeben, M.; Shi, X.; van Bibber, K.; Wenaus, T. J.; Wright, D. M.; Wuest, C. R.; Yamamoto, B.; Carroll, M.; Cooke, P.; Fry, J. R.; Gabathuler, E.; Gamet, R.; George, M.; Kay, M.; McMahon, S.; Muir, A.; Payne, D. J.; Sloane, R. J.; Sutcliffe, P.; Touramanis, C.; Aspinwall, M. L.; Bowerman, D. A.; Dauncey, P. D.; Eschrich, I.; Gunawardane, N. J. W.; Martin, R.; Nash, J. A.; Price, D. R.; Sanders, P.; Smith, D.; Azzopardi, D. E.; Back, J. J.; Dixon, P.; Harrison, P. F.; Newman-Coburn, D.; Potter, R. J. L.; Shorthouse, H. W.; Williams, M. I.; Vidal, P. B.; Cowan, G.; George, S.; Green, M. G.; Kurup, A.; Marker, C. E.; McGrath, P.; McMahon, T. R.; Salvatore, F.; Scott, I.; Vaitsas, G.; Brown, D.; Davis, C. L.; Li, Y.; Pavlovich, J.; Allison, J.; Barlow, R. J.; Boyd, J. T.; Fullwood, J.; Jackson, F.; Khan, A.; Lafferty, G. D.; Savvas, N.; Simopoulos, E. T.; Thompson, R. J.; Weatherall, J. H.; Bard, R.; Dallapiccola, C.; Farbin, A.; Jawahery, A.; Lillard, V.; Olsen, J.; Roberts, D. A.; Schieck, J. R.; Blaylock, G.; Flood, K. T.; Hertzbach, S. S.; Kofler, R.; Lin, C. S.; Willocq, S.; Wittlin, J.; Brau, B.; Cowan, R.; Taylor, F.; Yamamoto, R. K.; Britton, D. I.; Fernholz, R.; Houde, M.; Milek, M.; Patel, P. M.; Trischuk, J.; Lanni, F.; Palombo, F.; Bauer, J. M.; Booke, M.; Cremaldi, L.; Kroeger, R.; Reep, M.; Reidy, J.; Sanders, D. A.; Summers, D. J.; Arguin, J. F.; Beaulieu, M.; Martin, J. P.; Nief, J. Y.; Seitz, R.; Taras, P.; Woch, A.; Zacek, V.; Nicholson, H.; Sutton, C. S.; Cartaro, C.; Cavallo, N.; De Nardo, G.; Fabozzi, F.; Gatto, C.; Lista, L.; Piccolo, D.; Sciacca, C.; Cason, N. M.; LoSecco, J. M.; Alsmiller, J. R. G.; Gabriel, T. A.; Handler, T.; Heck, J.; Iwasaki, M.; Sinev, N. B.; Caracciolo, R.; Colecchia, F.; Dal Corso, F.; Galeazzi, F.; Marzolla, M.; Michelon, G.; Morandin, M.; Posocco, M.; Rotondo, M.; Santi, S.; Simonetto, F.; Stroili, R.; Torassa, E.; Voci, C.; Bailly, P.; Benayoun, M.; Briand, H.; Chauveau, J.; David, P.; De la Vaissière, C.; Del Buono, L.; Genat, J.-F.; Hamon, O.; Leruste, Ph.; Le Diberder, F.; Lebbolo, H.; Lory, J.; Martin, L.; Martinez-Vidal, F.; Roos, L.; Stark, J.; Versillé, S.; Zhang, B.; Manfredi, P. F.; Ratti, L.; Re, V.; Speziali, V.; Frank, E. D.; Gladney, L.; Guo, Q. H.; Panetta, J. H.; Angelini, C.; Batignani, G.; Bettarini, S.; Bondioli, M.; Bosi, F.; Carpinelli, M.; Forti, F.; Gaddi, A.; Gagliardi, D.; Giorgi, M. A.; Lusiani, A.; Mammini, P.; Morganti, M.; Morsani, F.; Neri, N.; Profeti, A.; Paoloni, E.; Raffaelli, F.; Rama, M.; Rizzo, G.; Sandrelli, F.; Simi, G.; Triggiani, G.; Haire, M.; Judd, D.; Paick, K.; Turnbull, L.; Wagoner, D. E.; Albert, J.; Bula, C.; Kelsey, M. H.; Lu, C.; McDonald, K. T.; Miftakov, V.; Sands, B.; Schaffner, S. F.; Smith, A. J. S.; Tumanov, A.; Varnes, E. W.; Bronzini, F.; Buccheri, A.; Bulfon, C.; Cavoto, G.; del Re, D.; Ferrarotto, F.; Ferroni, F.; Fratini, K.; Lamanna, E.; Leonardi, E.; Mazzoni, M. A.; Morganti, S.; Piredda, G.; Safai Tehrani, F.; Serra, M.; Voena, C.; Waldi, R.; Jacques, P. F.; Kalelkar, M.; Plano, R. J.; Adye, T.; Claxton, B.; Dowdell, J.; Egede, U.; Franek, B.; Galagedera, S.; Geddes, N. I.; Gopal, G. P.; Kay, J.; Lidbury, J.; Madani, S.; Metcalfe, S.; Metcalfe, S.; Markey, G.; Olley, P.; Watt, M.; Xella, S. M.; Aleksan, R.; Besson, P.; Bourgeois, P.; Convert, P.; De Domenico, G.; de Lesquen, A.; Emery, S.; Gaidot, A.; Ganzhur, S. F.; Georgette, Z.; Gosset, L.; Graffin, P.; Hamel de Monchenault, G.; Hervé, S.; Karolak, M.; Kozanecki, W.; Langer, M.; London, G. W.; Marques, V.; Mayer, B.; Micout, P.; Mols, J. P.; Mouly, J. P.; Penichot, Y.; Rolquin, J.; Serfass, B.; Toussaint, J. C.; Usseglio, M.; Vasseur, G.; Yeche, C.; Zito, M.; Copty, N.; Purohit, M. V.; Yumiceva, F. X.; Adam, I.; Adesanya, A.; Anthony, P. L.; Aston, D.; Bartelt, J.; Becla, J.; Bell, R.; Bloom, E.; Boeheim, C. T.; Boyarski, A. M.; Boyce, R. F.; Briggs, D.; Bulos, F.; Burgess, W.; Byers, B.; Calderini, G.; Chestnut, R.; Claus, R.; Convery, M. R.; Coombes, R.; Cottrell, L.; Coupal, D. P.; Coward, D. H.; Craddock, W. W.; DeBarger, S.; DeStaebler, H.; Dorfan, J.; Doser, M.; Dunwoodie, W.; Dusatko, J. E.; Ecklund, S.; Fieguth, T. H.; Freytag, D. R.; Glanzman, T.; Godfrey, G. L.; Haller, G.; Hanushevsky, A.; Harris, J.; Hasan, A.; Hee, C.; Himel, T.; Huffer, M. E.; Hung, T.; Innes, W. R.; Jessop, C. P.; Kawahara, H.; Keller, L.; King, M. E.; Klaisner, L.; Krebs, H. J.; Langenegger, U.; Langeveld, W.; Leith, D. W. G. S.; Louie, S. K.; Luitz, S.; Luth, V.; Lynch, H. L.; McDonald, J.; Manzin, G.; Marsiske, H.; Mattison, T.; McCulloch, M.; McDougald, M.; McShurley, D.; Menke, S.; Messner, R.; Metcalfe, S.; Morii, M.; Mount, R.; Muller, D. R.; Nelson, D.; Nordby, M.; O'Grady, C. P.; Olavson, L.; Olsen, J.; O'Neill, F. G.; Oxoby, G.; Paolucci, P.; Pavel, T.; Perl, J.; Pertsova, M.; Petrak, S.; Putallaz, G.; Raines, P. E.; Ratcliff, B. N.; Reif, R.; Robertson, S. H.; Rochester, L. S.; Roodman, A.; Russel, J. J.; Sapozhnikov, L.; Saxton, O. H.; Schietinger, T.; Schindler, R. H.; Schwiening, J.; Sciolla, G.; Seeman, J. T.; Serbo, V. V.; Shapiro, S.; Skarpass, K., Sr.; Snyder, A.; Soderstrom, E.; Soha, A.; Spanier, S. M.; Stahl, A.; Stiles, P.; Su, D.; Sullivan, M. K.; Talby, M.; Tanaka, H. A.; Va'vra, J.; Wagner, S. R.; Wang, R.; Weber, T.; Weinstein, A. J. R.; White, J. L.; Wienands, U.; Wisniewski, W. J.; Young, C. C.; Yu, N.; Burchat, P. R.; Cheng, C. H.; Kirkby, D.; Meyer, T. I.; Roat, C.; Henderson, R.; Khan, N.; Berridge, S.; Bugg, W.; Cohn, H.; Hart, E.; Weidemann, A. W.; Benninger, T.; Izen, J. M.; Kitayama, I.; Lou, X. C.; Turcotte, M.; Bianchi, F.; Bona, M.; Daudo, F.; Di Girolamo, B.; Gamba, D.; Grosso, P.; Smol, A.; Trapani, P. P.; Zanin, D.; Bosisio, L.; Della Ricca, G.; Lanceri, L.; Pompili, A.; Poropat, P.; Prest, M.; Rashevskaia, I.; Vallazza, E.; Vuagnin, G.; Panvini, R. S.; Brown, C.; De Silva, A.; Kowalewski, R.; Pitman, D.; Roney, J. M.; Band, H. R.; Charles, E.; Dasu, S.; Elmer, P.; Johnson, J. R.; Nielsen, J.; Orejudos, W.; Pan, Y.; Prepost, R.; Scott, I. J.; Walsh, J.; Wu, S. L.; Yu, Z.; Zobernig, H.; Moore, T. B.; Neal, H.

    2002-02-01

    B AB AR, the detector for the SLAC PEP-II asymmetric e +e - B Factory operating at the ϒ(4 S) resonance, was designed to allow comprehensive studies of CP-violation in B-meson decays. Charged particle tracks are measured in a multi-layer silicon vertex tracker surrounded by a cylindrical wire drift chamber. Electromagnetic showers from electrons and photons are detected in an array of CsI crystals located just inside the solenoidal coil of a superconducting magnet. Muons and neutral hadrons are identified by arrays of resistive plate chambers inserted into gaps in the steel flux return of the magnet. Charged hadrons are identified by d E/d x measurements in the tracking detectors and by a ring-imaging Cherenkov detector surrounding the drift chamber. The trigger, data acquisition and data-monitoring systems, VME- and network-based, are controlled by custom-designed online software. Details of the layout and performance of the detector components and their associated electronics and software are presented.

  8. Constraining the alteration history of a Late Cretaceous Patagonian volcaniclastic bentonite-ash-mudstone sequence using K-Ar and 40Ar/39Ar isotopes

    NASA Astrophysics Data System (ADS)

    Warr, L. N.; Hofmann, H.; van der Pluijm, B. A.

    2017-01-01

    Smectite is typically considered unsuitable for radiometric dating, as argon (40Ar) produced from decay of exchangeable potassium (40K) located in the interlayer sites can be lost during fluid-rock interaction and/or during wet sample preparation in the laboratory. However, age analysis of Late Cretaceous Argentinian bentonites and associated volcaniclastic rocks from Lago Pellegrini, Northern Patagonia, indicates that, in the case of these very low-permeability rocks, the radioactive 40Ar was retained and thus can provide information on smectite age and the timing of rock alteration. This study presents isotopic results that indicate the ash-to-bentonite conversion and alteration of the overlying tuffaceous mudstones in Northern Patagonia was complete 13-17 my after middle Campanian sedimentation when the system isotopically closed. The general absence of illite in these smectite-rich lithologies reflects the low activity of K and the low temperature (<60 °C) of the formation waters that altered the parent ash.

  9. Revised error propagation of 40Ar/39Ar data, including covariances

    NASA Astrophysics Data System (ADS)

    Vermeesch, Pieter

    2015-12-01

    The main advantage of the 40Ar/39Ar method over conventional K-Ar dating is that it does not depend on any absolute abundance or concentration measurements, but only uses the relative ratios between five isotopes of the same element -argon- which can be measured with great precision on a noble gas mass spectrometer. The relative abundances of the argon isotopes are subject to a constant sum constraint, which imposes a covariant structure on the data: the relative amount of any of the five isotopes can always be obtained from that of the other four. Thus, the 40Ar/39Ar method is a classic example of a 'compositional data problem'. In addition to the constant sum constraint, covariances are introduced by a host of other processes, including data acquisition, blank correction, detector calibration, mass fractionation, decay correction, interference correction, atmospheric argon correction, interpolation of the irradiation parameter, and age calculation. The myriad of correlated errors arising during the data reduction are best handled by casting the 40Ar/39Ar data reduction protocol in a matrix form. The completely revised workflow presented in this paper is implemented in a new software platform, Ar-Ar_Redux, which takes raw mass spectrometer data as input and generates accurate 40Ar/39Ar ages and their (co-)variances as output. Ar-Ar_Redux accounts for all sources of analytical uncertainty, including those associated with decay constants and the air ratio. Knowing the covariance matrix of the ages removes the need to consider 'internal' and 'external' uncertainties separately when calculating (weighted) mean ages. Ar-Ar_Redux is built on the same principles as its sibling program in the U-Pb community (U-Pb_Redux), thus improving the intercomparability of the two methods with tangible benefits to the accuracy of the geologic time scale. The program can be downloaded free of charge from

  10. 40Ar/39Ar and K-Ar data bearing on the metamorphic and tectonic history of western New England.

    USGS Publications Warehouse

    Sutter, J.F.; Ratcliffe, N.M.; Mukasa, S.B.

    1985-01-01

    40Ar/39Ar ages of coexisting biotite and hornblende from Proterozoic Y gneisses of the Berkshire and Green Mt massifs, as well as 40Ar/39Ar and K/Ar mineral and whole-rock ages from Palaeozoic metamorphic rocks, suggest that the thermal peaks for the dominant metamorphic recrystallization in western New England occurred 465 + or - 5 m.y. (Taconian). 40Ar/39Ar age data from a poorly-defined terrain along the eastern strip of the area suggests that the area has been retrograded during a metamorphism that peaked at least 376 + or - 5 m.y. (Acadian). Available age and petrological data from western New England indicate the presence of at least three separate metamorphic-structure domains of Taconic age: 1) a small area of relict high-P and low-T metamorphism, 2) a broad area of normal Barrovian metamorphism from chlorite to garnet grade characterized by a gentle metamorphic gradient and, 3) a rather narrow belt of steep-gradient, Barrovian series metamorphic rocks. Areas of maximum metamorphic intensity within the last domain coincide with areas of maximum crustal thickening in the later stage of Taconic orogeny. -L.di H

  11. Quadrupole collectivity beyond N = 28: intermediate-energy Coulomb excitation of (47,48)Ar.

    PubMed

    Winkler, R; Gade, A; Baugher, T; Bazin, D; Brown, B A; Glasmacher, T; Grinyer, G F; Meharchand, R; McDaniel, S; Ratkiewicz, A; Weisshaar, D

    2012-05-04

    We report on the first experimental study of quadrupole collectivity in the very neutron-rich nuclei (47,48)Ar using intermediate-energy Coulomb excitation. These nuclei are located along the path from doubly magic Ca to collective S and Si isotopes, a critical region of shell evolution and structural change. The deduced B(E2) transition strengths are confronted with large-scale shell-model calculations in the sdpf shell using the state-of-the-art SDPF-Uand EPQQM effective interactions. The comparison between experiment and theory indicates that a shell-model description of Ar isotopes around N=28 remains a challenge.

  12. Quadrupole Collectivity beyond N=28: Intermediate-Energy Coulomb Excitation of Ar47,48

    NASA Astrophysics Data System (ADS)

    Winkler, R.; Gade, A.; Baugher, T.; Bazin, D.; Brown, B. A.; Glasmacher, T.; Grinyer, G. F.; Meharchand, R.; McDaniel, S.; Ratkiewicz, A.; Weisshaar, D.

    2012-05-01

    We report on the first experimental study of quadrupole collectivity in the very neutron-rich nuclei Ar47,48 using intermediate-energy Coulomb excitation. These nuclei are located along the path from doubly magic Ca to collective S and Si isotopes, a critical region of shell evolution and structural change. The deduced B(E2) transition strengths are confronted with large-scale shell-model calculations in the sdpf shell using the state-of-the-art SDPF-Uand EPQQM effective interactions. The comparison between experiment and theory indicates that a shell-model description of Ar isotopes around N=28 remains a challenge.

  13. Spatial distribution of Ar-40/Ar-39 ages in lunar breccia 14301.

    NASA Technical Reports Server (NTRS)

    Megrue, G. H.

    1973-01-01

    The distribution of stable and radioactive argon isotopes in a lunar breccia has been measured in situ by laser probe mass spectrometry. This new technique determines the spatial distribution of Ar-40/Ar-39 ages on less than .1 milligram of material. Calculated Ar-40/Ar-39 ages of clasts within this breccia are 3.7 and 2.9 b.y. Parentless radiogenic Ar-40 exists within the fine-grained matrix and appears to have been trapped simultaneously with solar argon. This 'atmosphere' of ambient gas appears to have been incorporated into the rock by an impact event not more than 3 b.y. ago.

  14. ³⁹Ar/Ar measurements using ultra-low background proportional counters.

    PubMed

    Hall, Jeter; Aalseth, Craig E; Bonicalzi, Ricco M; Brandenberger, Jill M; Day, Anthony R; Humble, Paul H; Mace, Emily K; Panisko, Mark E; Seifert, Allen

    2016-01-01

    Age-dating groundwater and seawater using the (39)Ar/Ar ratio is an important tool to understand water mass-flow rates and mean residence time. Low-background proportional counters developed at Pacific Northwest National Laboratory use mixtures of argon and methane as counting gas. We demonstrate sensitivity to (39)Ar by comparing geological (ancient) argon recovered from a carbon dioxide gas well and commercial argon. The demonstrated sensitivity to the (39)Ar/Ar ratio is sufficient to date water masses as old as 1000 years.

  15. 40Ar/39Ar ages of lunar impact glasses: Relationships among Ar diffusivity, chemical composition, shape, and size

    NASA Astrophysics Data System (ADS)

    Zellner, N. E. B.; Delano, J. W.

    2015-07-01

    Lunar impact glasses, which are quenched melts produced during cratering events on the Moon, have the potential to provide not only compositional information about both the local and regional geology of the Moon but also information about the impact flux over time. We present in this paper the results of 73 new 40Ar/39Ar analyses of well-characterized, inclusion-free lunar impact glasses and demonstrate that size, shape, chemical composition, fraction of radiogenic 40Ar retained, and cosmic ray exposure (CRE) ages are important for 40Ar/39Ar investigations of these samples. Specifically, analyses of lunar impact glasses from the Apollo 14, 16, and 17 landing sites indicate that retention of radiogenic 40Ar is a strong function of post-formation thermal history in the lunar regolith, size, and chemical composition. This is because the Ar diffusion coefficient (at a constant temperature) is estimated to decrease by ∼3-4 orders of magnitude with an increasing fraction of non-bridging oxygens, X(NBO), over the compositional range of most lunar impact glasses with compositions from feldspathic to basaltic. Based on these relationships, lunar impact glasses with compositions and sizes sufficient to have retained ∼90% of their radiogenic Ar during 750 Ma of cosmic ray exposure at time-integrated temperatures of up to 290 K have been identified and are likely to have yielded reliable 40Ar/39Ar ages of formation. Additionally, ∼50% of the identified impact glass spheres have formation ages of ⩽500 Ma, while ∼75% of the identified lunar impact glass shards and spheres have ages of formation ⩽2000 Ma. Higher thermal stresses in lunar impact glasses quenched from hyperliquidus temperatures are considered the likely cause of poor survival of impact glass spheres, as well as the decreasing frequency of lunar impact glasses in general with increasing age. The observed age-frequency distribution of lunar impact glasses may reflect two processes: (i) diminished

  16. High-Throughput Genotyping with TaqMan Allelic Discrimination and Allele-Specific Genotyping Assays.

    PubMed

    Heissl, Angelika; Arbeithuber, Barbara; Tiemann-Boege, Irene

    2017-01-01

    Real-time PCR-based genotyping methods, such as TaqMan allelic discrimination assays and allele-specific genotyping, are particularly useful when screening a handful of single nucleotide polymorphisms in hundreds of samples; either derived from different individuals, tissues, or pre-amplified DNA. Although real-time PCR-based methods such as TaqMan are well-established, alternative methods, like allele-specific genotyping, are powerful alternatives, especially for genotyping short tandem repeat (STR) length polymorphisms. Here, we describe all relevant aspects when developing an assay for a new SNP or STR using either TaqMan or allele-specific genotyping, respectively, such as primer and probe design, optimization of reaction conditions, the experimental procedure for typing hundreds of samples, and finally the data evaluation. Our goal is to provide a guideline for developing genotyping assays using these two approaches that render reliable and reproducible genotype calls involving minimal optimization.

  17. Lgr4 promotes prostate tumorigenesis through the Jmjd2a/AR signaling pathway.

    PubMed

    Zhang, Jianwei; Li, Qi; Zhang, Shaojin; Xu, Quanquan; Wang, Tianen

    2016-11-15

    Lgr4 (leucine-rich repeat domain containing G protein-coupled receptor 4) is implicated in the transcriptional regulation of multiple histone demethylases in the progression of diverse cancers, but there are few reports concerning the molecular mechanism by which Lgr4 regulates histone demethylase activation in prostate cancer (PCa) progression. As Jmjd2a is a histone demethylase, in the current study, we investigated the relationship between interaction Lgr4 with Jmjd 2a and Jmjd2a/androgen receptor (AR) signaling pathway in PCa progression. Firstly, Lgr4 was overexpressed by transfecting pcDNA3.1(+)/Lgr4 plasmids into PCa (LNCaP and PC-3) cell lines. Next, we found that Lgr4 overexpression promoted Jmjd2a mRNA expression, reduced cell apoptosis and arrested cell cycle in the S phase, these effects were reversed by Jmjd2a silencing. Moreover, Lgr4 overexpression markedly elevated AR levels and its interaction with Jmjd2a, which was tested by co-immunoprecipitation and luciferase reporter assays. Furthermore, interaction AR with PSA promoter (containing an AR response element) was obviously improved by Lgr4 overexpression, and PSA silencing reduced Lgr4-induced cell apoptosis and cell cycle arrest in PCa cells. Taken together, Lgr4 may be a novel tumor marker providing new mechanistic insights into PCa progression. Lgr4 activates Jmjd2a/AR signaling pathway to promote interaction AR with PSA promoter, causing reduction of PCa apoptosis and cell cycle arrest.

  18. Hydrogen rich gas generator

    NASA Technical Reports Server (NTRS)

    Houseman, J. (Inventor)

    1976-01-01

    A process and apparatus is described for producing a hydrogen rich gas by introducing a liquid hydrocarbon fuel in the form of a spray into a partial oxidation region and mixing with a mixture of steam and air that is preheated by indirect heat exchange with the formed hydrogen rich gas, igniting the hydrocarbon fuel spray mixed with the preheated mixture of steam and air within the partial oxidation region to form a hydrogen rich gas.

  19. Rich catalytic injection

    DOEpatents

    Veninger, Albert

    2008-12-30

    A gas turbine engine includes a compressor, a rich catalytic injector, a combustor, and a turbine. The rich catalytic injector includes a rich catalytic device, a mixing zone, and an injection assembly. The injection assembly provides an interface between the mixing zone and the combustor. The injection assembly can inject diffusion fuel into the combustor, provides flame aerodynamic stabilization in the combustor, and may include an ignition device.

  20. 40Ar/39Ar Ages of Carbonaceous Xenoliths in 2 HED Meteorites

    NASA Technical Reports Server (NTRS)

    Turrin, B.; Lindsay, F. N.; Park, J.; Herzog, G. F.; Delaney, J. S.; Swisher, C. C., III; Johnson, J.; Zolensky, M.

    2016-01-01

    The generally young K/Ar and 40Ar/39Ar ages of CM chondrites made us wonder whether carbonaceous xenoliths (CMX) entombed in Howardite–Eucrite–Diogenite (HED) meteorites might retain more radiogenic 40Ar than do ‘free-range’ CM-chondrites. To find out, we selected two HED breccias with carbonaceous inclusions in order to compare the 40Ar/39Ar release patterns and ages of the inclusions with those of nearby HED material. Carbonaceous inclusions (CMXs) in two HED meteorites lost a greater fraction of radiogenic 40Ar than did surrounding host material, but a smaller fraction of it than did free-range CM-chondrites such as Murchison or more heavily altered ones. Importantly, however, the siting of the CMXs in HED matrix did not prevent the 40Ar loss of about 40 percent of the radiogenic 40Ar, even from phases that degas at high laboratory temperatures. We infer that carbonaceous asteroids with perihelia of 1 astronomical unit probably experience losses of at least this size. The usefulness of 40Ar/39Ar dating for samples returned from C-type asteroids may hinge, therefore, on identifying and analyzing separately small quantities of the most retentive phases of carbonaceous chondrites.

  1. 39Ar/Ar measurements using ultra-low background proportional counters

    SciTech Connect

    Hall, Jeter C.; Aalseth, Craig E.; Bonicalzi, Ricco; Brandenberger, Jill M.; Day, Anthony R.; Humble, Paul H.; Mace, Emily K.; Panisko, Mark E.; Seifert, Allen

    2016-01-08

    Age dating groundwater and seawater using 39Ar/Ar ratios is an important tool to understand water mass flow rates and mean residence time. For modern or contemporary argon, the 39Ar activity is 1.8 mBq per liter of argon. Radiation measurements at these activity levels require ultra low-background detectors. Low-background proportional counters have been developed at Pacific Northwest National Laboratory. These detectors use traditional mixtures of argon and methane as counting gas, and the residual 39Ar from commercial argon has become a predominant source of background activity in these detectors. We demonstrated sensitivity to 39Ar by using geological or ancient argon from gas wells in place of commercial argon. The low level counting performance of these proportional counters is then demonstrated for sensitivities to 39Ar/Ar ratios sufficient to date water masses as old as 1000 years.

  2. HLA-B alleles of the Cayapa of Ecuador: new B39 and B15 alleles.

    PubMed

    Garber, T L; Butler, L M; Trachtenberg, E A; Erlich, H A; Rickards, O; De Stefano, G; Watkins, D I

    1995-01-01

    Recent data suggest that HLA-B locus alleles can evolve quickly in native South American populations. To investigate further this phenomenon of new HLA-B variants among Amerindians, we studied samples from another South American tribe, the Cayapa from Ecuador. We selected individuals for HLA-B molecular typing based upon their HLA class II typing results. Three new variants of HLA-B39 and one new variant of HLA-B15 were found in the Cayapa: HLA-B*3905, HLA-B*3906, HLA-B*3907, and HLA-B*1522. A total of thirteen new HLA-B alleles have now been found in the four South American tribes studied. Each of these four tribes studied, including the Cayapa, had novel alleles that were not found in any of the other tribes, suggesting that many of these new HLA-B alleles may have evolved since the Paleo-Indians originally populated South America. Each of these 13 new alleles contained predicted amino acid replacements that were located in the peptide binding site. These amino acid replacements may affect the sequence motif of the bound peptides, suggesting that these new alleles have been maintained by selection. New allelic variants have been found for all common HLA-B locus antigenic groups present in South American tribes with the exception of B48. In spite of its high frequency in South American tribes, no evidence for variants of B48 has been found in all the Amerindians studied, suggesting that B48 may have unique characteristics among the B locus alleles.

  3. Research: Rags to Rags? Riches to Riches?

    ERIC Educational Resources Information Center

    Bracey, Gerald W.

    2004-01-01

    Everyone has read about what might be called the "gold gap"--how the rich in this country are getting richer and controlling an ever-larger share of the nation's wealth. The Century Foundation has started publishing "Reality Check", a series of guides to campaign issues that sometimes finds gaps in these types of cherished delusions. The guides…

  4. arXiv.org and Physics Education

    NASA Astrophysics Data System (ADS)

    Ramlo, Susan

    2007-09-01

    The website arXiv.org (pronounced archive) is a free online resource for full-text articles in the fields of physics, mathematics, computer science, nonlinear science, and quantitative biology that has existed for about 15 years. Available directly at http://www.arXiv.org, this e-print archive is searchable. As of Jan. 3, 2007, arXiv had open access to 401,226 e-prints in the topic areas. Those who sign up for an ID and password can also sign up for daily submission abstract emails for specific subject classes of arXiv, including physics education, physics and society, and history of physics. Founded and developed by Paul Ginsparg when he was at Los Alamos National Laboratory, arXiv's original name was the LANL preprint archive or xxx.lanl.gov. The location and name changed after Ginsparg moved to the physics department at Cornell University. Today, arXiv is hosted and operated by Cornell University library. Mirror sites for arXiv exist worldwide.2

  5. Initial invasion of gametophytic self-incompatibility alleles in the absence of tight linkage between pollen and pistil S alleles.

    PubMed

    Sakai, Satoki; Wakoh, Haluka

    2014-08-01

    In homomorphic self-incompatibility (SI) systems of plants, the loci controlling the pollen and pistil types are tightly linked, and this prevents the generation of compatible combinations of alleles expressing pollen and pistil types, which would result in self-fertilization. We modeled the initial invasion of the first pollen and pistil alleles in gametophytic SI to determine whether these alleles can stably coexist in a population without tight linkage. We assume pollen and pistil loci each carry an incompatibility allele S and an allele without an incompatibility function N. We assume that pollen with an S allele are incompatible with pistils carrying S alleles, whereas other crosses are compatible. Ovules in pistils carrying an S allele suffer viability costs because recognition consumes resources. We found that the cost of carrying a pistil S allele allows pollen and pistil S alleles to coexist in a stable equilibrium if linkage is partial. This occurs because parents that carry pistil S alleles but are homozygous for pollen N alleles cannot avoid self-fertilization; however, they suffer viability costs. Hence, pollen N alleles are selected again. When pollen and pistil S alleles can coexist in a polymorphic equilibrium, selection will favor tighter linkage.

  6. Do Heliconius butterfly species exchange mimicry alleles?

    PubMed Central

    Smith, Joel; Kronforst, Marcus R.

    2013-01-01

    Hybridization has the potential to transfer beneficial alleles across species boundaries, and there are a growing number of examples in which this has apparently occurred. Recent studies suggest that Heliconius butterflies have transferred wing pattern mimicry alleles between species via hybridization, but ancestral polymorphism could also produce a signature of shared ancestry around mimicry genes. To distinguish between these alternative hypotheses, we measured DNA sequence divergence around putatively introgressed mimicry loci and compared this with the rest of the genome. Our results reveal that putatively introgressed regions show strongly reduced sequence divergence between co-mimetic species, suggesting that their divergence times are younger than the rest of the genome. This is consistent with introgression and not ancestral variation. We further show that this signature of introgression occurs at sites throughout the genome, not just around mimicry genes. PMID:23864282

  7. Allelic variation contributes to bacterial host specificity

    SciTech Connect

    Yue, Min; Han, Xiangan; Masi, Leon De; Zhu, Chunhong; Ma, Xun; Zhang, Junjie; Wu, Renwei; Schmieder, Robert; Kaushik, Radhey S.; Fraser, George P.; Zhao, Shaohua; McDermott, Patrick F.; Weill, François-Xavier; Mainil, Jacques G.; Arze, Cesar; Fricke, W. Florian; Edwards, Robert A.; Brisson, Dustin; Zhang, Nancy R.; Rankin, Shelley C.; Schifferli, Dieter M.

    2015-10-30

    Understanding the molecular parameters that regulate cross-species transmission and host adaptation of potential pathogens is crucial to control emerging infectious disease. Although microbial pathotype diversity is conventionally associated with gene gain or loss, the role of pathoadaptive nonsynonymous single-nucleotide polymorphisms (nsSNPs) has not been systematically evaluated. Here, our genome-wide analysis of core genes within Salmonella enterica serovar Typhimurium genomes reveals a high degree of allelic variation in surface-exposed molecules, including adhesins that promote host colonization. Subsequent multinomial logistic regression, MultiPhen and Random Forest analyses of known/suspected adhesins from 580 independent Typhimurium isolates identifies distinct host-specific nsSNP signatures. Moreover, population and functional analyses of host-associated nsSNPs for FimH, the type 1 fimbrial adhesin, highlights the role of key allelic residues in host-specific adherence in vitro. In conclusion, together, our data provide the first concrete evidence that functional differences between allelic variants of bacterial proteins likely contribute to pathoadaption to diverse hosts.

  8. Allelic variation contributes to bacterial host specificity

    DOE PAGES

    Yue, Min; Han, Xiangan; Masi, Leon De; ...

    2015-10-30

    Understanding the molecular parameters that regulate cross-species transmission and host adaptation of potential pathogens is crucial to control emerging infectious disease. Although microbial pathotype diversity is conventionally associated with gene gain or loss, the role of pathoadaptive nonsynonymous single-nucleotide polymorphisms (nsSNPs) has not been systematically evaluated. Here, our genome-wide analysis of core genes within Salmonella enterica serovar Typhimurium genomes reveals a high degree of allelic variation in surface-exposed molecules, including adhesins that promote host colonization. Subsequent multinomial logistic regression, MultiPhen and Random Forest analyses of known/suspected adhesins from 580 independent Typhimurium isolates identifies distinct host-specific nsSNP signatures. Moreover, population andmore » functional analyses of host-associated nsSNPs for FimH, the type 1 fimbrial adhesin, highlights the role of key allelic residues in host-specific adherence in vitro. In conclusion, together, our data provide the first concrete evidence that functional differences between allelic variants of bacterial proteins likely contribute to pathoadaption to diverse hosts.« less

  9. 40Ar/39Ar Dating Reveals Multiple Generations of Mafic Dikes in Southeastern Alaska

    NASA Astrophysics Data System (ADS)

    Oconnell, K.; Davidson, C.; Singer, B.

    2004-12-01

    Seven 40Ar/39Ar whole-rock incremental heating dates of mafic dikes from the Wrangell transect in southeastern Alaska yield six concordant plateau dates of 14.7 ± 1.0 Ma, 24.7 ± 1.1 Ma, 30.1 ± 0.2 Ma, 41.8 ± 1.1 Ma, 107.5 ± 0.5 Ma, and 113.0 ± 0.7 Ma. One sample is discordant with most of the steps yielding dates >220 Ma. We also obtained a well-defined plateau date of 115.6 ± 0.3 Ma from a hornblende separate from the sample that yielded the 113.0 ± 0.7 Ma whole-rock date. The concordance of these two dates suggests that the whole-rock dates probably reflect a close approximation of the emplacement and crystallization ages of the dikes. The mafic dikes sampled for this study have distinct chilled margins and are 0.5-5 meter thick alkali-rich basalts and basaltic andesite. The dikes crosscut all ductile fabrics and define two main sets in orientation. One set strikes NNW and dips steeply to the east and the other set strikes NE with steep SE dips. Based on crosscutting relationships, the NNW dikes appear to be older and are mostly found west of Clarence Straight. The mid-Cretaceous dikes dated in this study intrude Silurian age rocks of the Alexander terrane and are confined to the western part of the Wrangell transect. The younger (14.7 - 41.8 Ma) dikes are found throughout the study area including within variably metamorphosed Jurassic-Cretaceous meta-sedimentary rocks, mid-Cretaceous plutons, and Tertiary volcanic rocks. These new dates show that mafic dikes intruded the Alexander terrane during mid-Cretaceous shortening in SE Alaska. This suggests that basaltic magmatism occurred in SE Alaska during the final accretion of the Alexander/Wrangellia terrane and during subsequent Cenozoic deformation along a transpressive to transtensional plate boundary.

  10. Instrumentation development for planetary in situ 40Ar/39Ar geochronology

    NASA Astrophysics Data System (ADS)

    Davidheiser-Kroll, B.; Morgan, L. E.; Munk, M.; Warner, N. H.; Gupta, S.; Slaybaugh, R.; Harkness, P.; Mark, D. F.

    2015-12-01

    The chronology of the Solar System, particularly the timing of formation of extraterrestrial bodies and their features, is a major outstanding problem in planetary science. Although various chronological methods for in situ geochronology have been proposed (e.g. Rb-Sr, K-Ar), and even applied (K-Ar, Farley et al., 2014), the reliability, accuracy, and applicability of the 40Ar/39Ar method makes it by far the most desirable chronometer for dating extraterrestrial bodies. The method however relies on the neutron irradiation of samples, and thus a neutron source. We will discuss the challenges and feasibility of deploying a passive neutron source to planetary surfaces for the in situ application of the 40Ar/39Ar chronometer. Requirements in generating and shielding neutrons, as well as analyzing samples are discussed, along with an exploration of limitations such as mass, power, and cost. Two potential solutions for the in situ extraterrestrial deployment of the 40Ar/39Ar method will be presented. Although this represents a challenging task, developing the technology to apply the 40Ar/39Ar method on planetary surfaces would represent a major advance towards constraining the timescale of solar system formation and evolution.

  11. Ar-40/Ar-39 Studies of Martian Meteorite RBT 04262 and Terrestrial Standards

    NASA Technical Reports Server (NTRS)

    Park, J.; Herzog, G. F.; Turrin, B.; Lindsay, F. N.; Delaney, J. S.; Swisher, C. C., III; Nagao, K.; Nyquist, L. E.

    2014-01-01

    Park et al. recently presented an Ar-40/Ar-39 dating study of maskelynite separated from the Martian meteorite RBT 04262. Here we report an additional study of Ar-40/Ar-39 patterns for smaller samples, each consisting of only a few maskelynite grains. Considered as a material for Ar-40/Ar-39 dating, the shock-produced glass maskelynite has both an important strength (relatively high K concentration compared to other mineral phases) and some potentially problematic weaknesses. At Rutgers, we have been analyzing small grains consisting of a single phase to explore local effects that might be averaged and remain hidden in larger samples. Thus, to assess the homogeneity of the RBT maskelynite and for comparison with the results of, we analyzed six approx. 30 microgram samples of the same maskelynite separate they studied. Furthermore, because most Ar-40/Ar-39 are calculated relative to the age of a standard, we present new Ar-40/Ar-39 age data for six standards. Among the most widely used standards are sanidine from Fish Canyon (FCs) and various hornblendes (hb3gr, MMhb-1, NL- 25), which are taken as primary standards because their ages have been determined by independent, direct measurements of K and A-40.

  12. Abundance and Composition of K and Ca Bearing Minerals in Ordinary Chondrites and Their Application to Ar-Ar Dating

    NASA Astrophysics Data System (ADS)

    Weirich, J. R.; Swindle, T. D.

    2007-03-01

    Compositionally uniform albite accounts for all K in two H chondrites studied. Two K/Ca ratios are observed in individual meteorites in Ar-Ar experiments, however, which must indicate two separate releases of Ar from albite.

  13. Ar-Ar Thermochronlogy of Apollo 12 Impact-Melt Breccia 12033,638-1

    NASA Technical Reports Server (NTRS)

    Crow, C. A.; Cassata, W. S.; Jolliff, B. L.; Ziegler, R. A.; Borg, L. E.; Shearer, C. K.

    2017-01-01

    We have undertaken an Ar-Ar thermochronology investigation as part of a coordinated multichronometer analysis of a single Apollo 12 impact- melt breccia to demonstrate the wide range of information that can be obtained for a single complex rock. This has implications for the age of formation, component makeup, and subsequent impact/shock and exposure history of the sample. This study also serves as a capabilities demonstration for the proposed MoonRise Mission [1]. The goal of this investigation is to elucidate the history of this sample through coordinated 40Ar*/39Ar, Sm-Nd, Rb-Sr and zircon 207Pb-206Pb ages along with geochemical and petrographic context on a relatively small (approximately 450 mg) sample. Here, we report preliminary results of the Ar-Ar thermochronology.

  14. Ar-39-Ar-40 Ages of Euerites and the Thermal History of Asteroid 4-Vesta

    NASA Technical Reports Server (NTRS)

    Bogard, Donald D.; Garrison, Daniel H.

    2002-01-01

    Eucrite meteorites are igneous rocks that derive from a large asteroid, probably 4 Vesta. Prior studies have shown that after eucrites formed, most were subsequently metamorphosed to temperatures up to equal to or greater than 800 C, and much later many were brecciated and heated by large impacts into the parent body surface. The uncommon basaltic, unbrecciated eucrites also formed near the surface but presumably escaped later brecciation, whereas the cumulate eucrites formed at depth where metamorphism may have persisted for a considerable period. To further understand the complex HED parent body thermal history, we determined new Ar-39-Ar-40 ages for nine eucrites classified as basaltic but unbrecciated, six eucrites classified as cumulate, and several basaltic-brecciated eucrites. Relatively precise Ar-Ar ages of two cumulate eucrites (Moama and EET87520) and four unbrecciated eucrites give a tight cluster at 4.48 +/1 0.01 Gyr. Ar-Ar ages of six additional unbrecciated eucrites are consistent with this age, within their larger age uncertainties. In contrast, available literature data on Pb-Pb isochron ages of four cumulate eucrites and one unbrecciated eucrite vary over 4.4-4.515 Gyr, and Sm-147 - Nd-143 isochron ages of four cumulate and three unbrecciated eucrites vary over 4.41-4.55 Gyr. Similar Ar-Ar ages for cumulate and unbrecciated eucrites imply that cumulate eucrites do not have a younger formation age than basaltic eucrites, as previously proposed. Rather, we suggest that these cumulate and unbrecciated eucrites resided at depth where parent body temperatures were sufficiently high to cause the K-Ar and some other chronometers to remain open diffusion systems. From the strong clustering of Ar-Ar ages at approximately 4.48 Gyr, we propose that these meteorites were excavated from depth in a single large impact event approximately 4.48 Gyr ago, which quickly cooled the samples and started the K-Ar chronometer. A large (approximately 460 km) crater

  15. LASER MICROPROBE **4**0Ar/**3**9Ar DATING OF MINERAL GRAINS IN SITU.

    USGS Publications Warehouse

    Sutter, J.F.; Hartung, J.B.

    1984-01-01

    A laser-microprobe attached to a mass spectrometer for **4**0Ar/**3**9Ar age determination of single mineral grains in geological materials has been made operational at the US Geological Survey, Reston, VA. This microanalytical technique involves focusing a pulsed laser beam onto a sample contained in an ultra-high vacuum chamber attached to a rare-gas mass spectrometer. Argon in the neutron-irradiated sample is released by heating with the laser pulse and its isotopic composition is measured to yield an **4**0Ar/**3**9Ar age. Laser probe **4**0Ar/**3**9Ar ages of single mineral grains measured in situ can aid greatly in understanding the chronology of many geological situations where datable minerals are present but are not physically separable in quantities needed for conventional age dating.

  16. Increasing long term response by selecting for favorable minor alleles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Long-term response of genomic selection can be improved by considering allele frequencies of selected markers or quantitative trait loci (QTLs). A previous formula to weight allele frequency of favorable minor alleles was tested, and 2 new formulas were developed. The previous formula used nonlinear...

  17. Mutant maize variety containing the glt1-1 allele

    DOEpatents

    Nelson, O.E.; Pan, D.

    1994-07-19

    A maize plant has in its genome a non-mutable form of a mutant allele designated vitX-8132. The allele is located at a locus designated as glt which conditions kernels having an altered starch characteristic. Maize plants including such a mutant allele produce a starch that does not increase in viscosity on cooling, after heating. 2 figs.

  18. Mutant maize variety containing the glt1-1 allele

    DOEpatents

    Nelson, Oliver E.; Pan, David

    1994-01-01

    A maize plant has in its genome a non-mutable form of a mutant allele designated vitX-8132. The allele is located at a locus designated as glt which conditions kernels having an altered starch characteristic. Maize plants including such a mutant allele produce a starch that does not increase in viscosity on cooling, after heating.

  19. Alleles versus mutations: Understanding the evolution of genetic architecture requires a molecular perspective on allelic origins.

    PubMed

    Remington, David L

    2015-12-01

    Perspectives on the role of large-effect quantitative trait loci (QTL) in the evolution of complex traits have shifted back and forth over the past few decades. Different sets of studies have produced contradictory insights on the evolution of genetic architecture. I argue that much of the confusion results from a failure to distinguish mutational and allelic effects, a limitation of using the Fisherian model of adaptive evolution as the lens through which the evolution of adaptive variation is examined. A molecular-based perspective reveals that allelic differences can involve the cumulative effects of many mutations plus intragenic recombination, a model that is supported by extensive empirical evidence. I discuss how different selection regimes could produce very different architectures of allelic effects under a molecular-based model, which may explain conflicting insights on genetic architecture from studies of variation within populations versus between divergently selected populations. I address shortcomings of genome-wide association study (GWAS) practices in light of more suitable models of allelic evolution, and suggest alternate GWAS strategies to generate more valid inferences about genetic architecture. Finally, I discuss how adopting more suitable models of allelic evolution could help redirect research on complex trait evolution toward addressing more meaningful questions in evolutionary biology.

  20. The ArsD As(III) metallochaperone

    PubMed Central

    Ajees, A. Abdul; Yang, Jianbo

    2013-01-01

    Arsenic, a toxic metalloid widely existing in the environment, causes a variety of health problems. The ars operon encoded by Escherichia coli plasmid R773 has arsD and arsA genes, where ArsA is an ATPase that is the catalytic subunit of the ArsAB As(III) extrusion pump, and ArsD is an arsenic chaperone for ArsA. ArsD transfers As(III) to ArsA and increases the affinity of ArsA for As(III), allowing resistance to environmental concentrations of arsenic. Cys12, Cys13 and Cys18 in ArsD form a three sulfur-coordinated As(III) binding site that is essential for metallochaperone activity. ATP hydrolysis by ArsA is required for transfer of As(III) from ArsD to ArsA, suggesting that transfer occurs with a conformation of ArsA that transiently forms during the catalytic cycle. The 1.4 Å x-ray crystal structure of ArsD shows a core of four β-strands flanked by four α-helices in a thioredoxin fold. Docking of ArsD with ArsA was modeled in silico. Independently ArsD mutants exhibiting either weaker or stronger interaction with ArsA were selected. The locations of the mutations mapped on the surface of ArsD are consistent with the docking model. The results suggest that the interface with ArsA involves one surface of α1 helix and metalloid binding site of ArsD. PMID:21188475

  1. Identification of the third/extra allele for forensic application in cases with TPOX tri-allelic pattern.

    PubMed

    Picanço, Juliane Bentes; Raimann, Paulo Eduardo; da Motta, Carlos Henrique Ares Silveira; Rodenbusch, Rodrigo; Gusmão, Leonor; Alho, Clarice Sampaio

    2015-05-01

    Genotyping of polymorphic short tandem repeats (STRs) loci is widely used in forensic DNA analysis. STR loci eventually present tri-allelic pattern as a genotyping irregularity and, in that situation, the doubt about the tri-allele locus frequency calculation can reduce the analysis strength. In the TPOX human STR locus, tri-allelic genotypes have been reported with a widely varied frequency among human populations. We investigate whether there is a single extra allele (the third allele) in the TPOX tri-allelic pattern, what it is, and where it is, aiming to understand its genomic anatomy and to propose the knowledge of this TPOX extra allele from genetic profile, thus preserving the two standard TPOX alleles in forensic analyses. We looked for TPOX tri-allelic subjects in 75,113 Brazilian families. Considering only the parental generation (mother+father) we had 150,226 unrelated subjects evaluated. From this total, we found 88 unrelated subjects with tri-allelic pattern in the TPOX locus (0.06%; 88/150,226). Seventy three of these 88 subjects (73/88; 83%) had the Clayton's original Type 2 tri-allelic pattern (three peaks of even intensity). The remaining 17% (15/88) show a new Type 2 derived category with heterozygote peak imbalance (one double dose peak plus one regular sized peak). In this paper we present detailed data from 66 trios (mother+father+child) with true biological relationships. In 39 of these families (39/66; 59%) the extra TPOX allele was transmitted either from the mother or from the father to the child. Evidences indicated the allele 10 as the extra TPOX allele, and it is on the X chromosome. The present data, which support the previous Lane hypothesis, improve the knowledge about tri-allelic pattern of TPOX CODIS' locus allowing the use of TPOX profile in forensic analyses even when with tri-allelic pattern. This evaluation is now available for different forensic applications.

  2. Dating samples of lunar soil from the Mare Crisium by the Ar/39/-Ar/40/ technique

    NASA Astrophysics Data System (ADS)

    Shanin, L. L.; Arakeliants, M. M.; Bogatikov, O. A.; Ivanenko, V. V.; Pupyrev, Iu. G.; Tarasov, L. S.; Frikh-Khar, D. I.

    1981-07-01

    Two samples (dolerite and gabbro fragments) from a depth of 184 cm in the Luna 24 core are dated using the Ar(39)-Ar(40) technique. The values obtained are found to be lower than all published isotopic ages for the Luna 24 samples. An analysis of possible dating errors of the lunar samples, together with the good agreement of the results from the Ar(39)-Ar(40) technique of geochronologic standards and anorthosite from the Korosten pluton with the results from Rb-Sr, U-Pb, and Sm-Nd methods, attests the reliability of the values.

  3. Rapid kimberlite ascent and the significance of Ar-Ar ages in xenolith phlogopites

    PubMed

    Kelley; Wartho

    2000-07-28

    Kimberlite eruptions bring exotic rock fragments and minerals, including diamonds, from deep within the mantle up to the surface. Such fragments are rapidly absorbed into the kimberlite magma so their appearance at the surface implies rapid transport from depth. High spatial resolution Ar-Ar age data on phlogopite grains in xenoliths from Malaita in the Solomon Islands, southwest Pacific, and Elovy Island in the Kola Peninsula, Russia, indicate transport times of hours to days depending upon the magma temperature. In addition, the data show that the phlogopite grains preserve Ar-Ar ages recorded at high temperature in the mantle, 700 degrees C above the conventional closure temperature.

  4. 39Ar - 40Ar Studies of Lherzolitic Shergottites Yamato 000097 and 984028

    NASA Technical Reports Server (NTRS)

    Park, J.; Nyquist, L. E.; Bogard, D. D.; Garrison, D. H.; Shih, C.-Y.; Mikouchi, T.; Misawa, K.

    2010-01-01

    Yamato 984028 (Y984028) was discovered by the Japanese Antarctic Research Expedition (JARE) in 1998 and recently classified as a lherzolitic shergottite with large pyroxene oikocrysts enclosing rounded olivine and chromites. It also contains shock veining and maskelynite. Y984028 is paired with the more recent lherzolitic shergottite finds Y000027/47/97 based on similarities in mineralogy and chemistry, as well as isotopic composition. We present here the studied Ar-39-Ar-40 of Y-984028 whole rock (WR) and pyroxene (Px), in order to gain better understanding of trapped Ar components with a comparison of the possibly-paired Y000097 Ar release.

  5. 40Ar/39Ar ages of the AD 79 eruption of Vesuvius, Italy

    USGS Publications Warehouse

    Lanphere, Marvin A.; Champion, Duane E.; Melluso, Leone; Morra, Vincenzo; Perrotta, Annamaria; Scarpati, Claudio; Tedesco, Dario; Calvert, Andrew T.

    2007-01-01

    The Italian volcano, Vesuvius, erupted explosively in AD 79. Sanidine from pumice collected at Casti Amanti in Pompeii and Villa Poppea in Oplontis yielded a weighted-mean 40Ar/39Ar age of 1925±66 years in 2004 (1σ uncertainty) from incremental-heating experiments of eight aliquants of sanidine. This is the calendar age of the eruption. Our results together with the work of Renne et al. (1997) and Renne and Min (1998) demonstrate the validity of the 40Ar/39Ar method to reconstruct the recent eruptive history of young, active volcanoes.

  6. 40Ar/39Ar ages of the AD 79 eruption of Vesuvius, Italy

    NASA Astrophysics Data System (ADS)

    Lanphere, Marvin; Champion, Duane; Melluso, Leone; Morra, Vincenzo; Perrotta, Annamaria; Scarpati, Claudio; Tedesco, Dario; Calvert, Andrew

    2007-01-01

    The Italian volcano, Vesuvius, erupted explosively in AD 79. Sanidine from pumice collected at Casti Amanti in Pompeii and Villa Poppea in Oplontis yielded a weighted-mean 40Ar/39Ar age of 1925±66 years in 2004 (1σ uncertainty) from incremental-heating experiments of eight aliquants of sanidine. This is the calendar age of the eruption. Our results together with the work of Renne et al. (1997) and Renne and Min (1998) demonstrate the validity of the 40Ar/39Ar method to reconstruct the recent eruptive history of young, active volcanoes.

  7. Ar-39-Ar-40 Evidence for Early Impact Events on the LL Parent Body

    NASA Technical Reports Server (NTRS)

    Dixon, E. T.; Bogard, D. D.; Garrison, D. H.; Rubin, A. E.

    2006-01-01

    We determined Ar-39-Ar-40 ages of eight LL chondrites, and one igneous inclusion from an LL chondrite, with the object of understanding the thermal history of the LL-chondrite parent body. The meteorites in this study have a range of petrographic types from LL3.3 to LL6, and shock stages from S1 to S4. These meteorites reveal a range of K-Ar ages from 23.66 to 24.50 Ga, and peak ages from 23.74 to 24.55 Ga. Significantly, three of the eight chondrites (LL4, 5, 6) have K-Ar ages of -4.27 Ga. One of these (MIL99301) preserves an Ar-39-Ar-40 age of 4.23 +/- 0.03 Ga from low-temperature extractions, and an older age of 4.52 +/- 0.08 Ga from the highest temperature extractions. In addition, an igneous-textured impact melt DOM85505,22 has a peak Ar-39-Ar-40 age of >= 4.27 Ga. We interpret these results as evidence for impact events that occurred at about 4.27 Ga on the LL parent body that produced local impact melts, reset the Ar-39-Ar-40 ages of some meteorites, and exhumed (or interred) others, resulting in a range of cooling ages. The somewhat younger peak age of 3.74 Ga from GR095658 (LL3.3) suggests an additional impact event close to timing of impact-reset ages of some other ordinary chondrites between 3.6-3.8 Ga. The results from MIL99301 suggest that some apparently unshocked (Sl) chondrites may have substantially reset Ar-39-Ar-40 ages. A previous petrographic investigation of MIL99301 suggested that reheating to temperatures less than or equal to type 4 petrographic conditions (600C) caused fractures in olivine to anneal, resulting in a low apparent shock stage of S1 (unshocked). The Ar-39-Ar-40 age spectrum of MIL99301 is consistent with this interpretation. Older ages from high-T extractions may date an earlier impact event at 4.52 +/- 0.08 Ga, whereas younger ages from lower-T extractions date a later impact event at 4.23 Ar-39-Ar-40 0.03 Ga that may have caused annealing of feldspar and olivine

  8. Experimental Constraints on He, Ne, Ar Behavior at Mantle Conditions

    NASA Astrophysics Data System (ADS)

    Jackson, C.; Kelley, S. P.; Parman, S. W.; Cooper, R. F.

    2010-12-01

    We have experimentally constrained He, Ne and Ar mineral-melt partitioning for olivine, enstatite and spinel under mantle P-T conditions. The experiments were run in a piston cylinder apparatus. Run products were analyzed by UV laser ablation microprobe (UVLAMP). Our data (Ol, Opx, Sp), along with literature data (Cpx), suggest He, Ne and Ar are incompatible during mantle melting. Gem quality crystals of En100, Sp and Fo90 were polished using colloidal silica and loaded along with a MgO rich, synthetic MORB powder into a graphite inner and Pt outer capsule. Within the inner capsule, crystals were faced against graphite, an identical crystal or polished glassy carbon. Equal pressures (40-60 total bars) of He, Ne and Ar were loaded into the outer capsule before it was welded closed. The run conditions were 1450C and 1-2 GPa for 10 hrs (Brown University). Depth profiles of the mineral faces were obtained using a 193 nm excimer laser (Open University). The large crystal area and short wavelength laser allows for measurements with high depth resolution and concentration precision: a 400 um aperture with 150 nm ablation depth can provide a detection limit (3 sigma > blank) of ~500 ppb He, ~1 ppm Ne and ~500 ppb Ar. Three mineral ablation pits were imaged using a white light interferometer at Tufts University and indicate an ablation rate of ~25 nm/pulse. Glass ablation rates are estimated using previous measurements. The melts were generally understaturated with respect to He, Ne and Ar (1-10, 3-200 and 4-1000 PPM, respectively). Concentrations in the minerals were mostly below detection limits. Where detectable, near surface gas concentrations visually correlate with the amount of adhering graphite. This could be due to trapped/adsorbed gas in the graphite or to surface deformation produced by the graphite. The surface with the least adhering graphite and smoothest surface (faced against glassy carbon) shows no observable near surface enrichment of He, Ne or Ar. Given

  9. Update on allele nomenclature for human cytochromes P450 and the Human Cytochrome P450 Allele (CYP-allele) Nomenclature Database.

    PubMed

    Sim, Sarah C; Ingelman-Sundberg, Magnus

    2013-01-01

    Interindividual variability in xenobiotic metabolism and drug response is extensive and genetic factors play an important role in this variation. A majority of clinically used drugs are substrates for the cytochrome P450 (CYP) enzyme system and interindividual variability in expression and function of these enzymes is a major factor for explaining individual susceptibility for adverse drug reactions and drug response. Because of the existence of many polymorphic CYP genes, for many of which the number of allelic variants is continually increasing, a universal and official nomenclature system is important. Since 1999, all functionally relevant polymorphic CYP alleles are named and published on the Human Cytochrome P450 Allele (CYP-allele) Nomenclature Web site (http://www.cypalleles.ki.se). Currently, the database covers nomenclature of more than 660 alleles in a total of 30 genes that includes 29 CYPs as well as the cytochrome P450 oxidoreductase (POR) gene. On the CYP-allele Web site, each gene has its own Webpage, which lists the alleles with their nucleotide changes, their functional consequences, and links to publications identifying or characterizing the alleles. CYP2D6, CYP2C9, CYP2C19, and CYP3A4 are the most important CYPs in terms of drug metabolism, which is also reflected in their corresponding highest number of Webpage hits at the CYP-allele Web site.The main advantage of the CYP-allele database is that it offers a rapid online publication of CYP-alleles and their effects and provides an overview of peer-reviewed data to the scientific community. Here, we provide an update of the CYP-allele database and the associated nomenclature.

  10. 40Ar/39Ar ages in deformed potassium feldspar: evidence of microstructural control on Ar isotope systematics

    NASA Astrophysics Data System (ADS)

    Reddy, Steven M.; Potts, Graham J.; Kelley, Simon P.

    2001-05-01

    Detailed field and microstructural studies have been combined with high spatial resolution ultraviolet laser 40Ar/39Ar dating of naturally deformed K-feldspar to investigate the direct relationship between deformation-related microstructure and Ar isotope systematics. The sample studied is a ~1,000 Ma Torridonian arkose from Skye, Scotland, that contains detrital feldspars previously metamorphosed at amphibolite-facies conditions ~1,700 Ma. The sample was subsequently deformed ~430 Ma ago during Caledonian orogenesis. The form and distribution of deformation-induced microstructures within three different feldspar clasts has been mapped using atomic number contrast and orientation contrast imaging, at a range of scales, to identify intragrain variations in composition and lattice orientation. These variations have been related to thin section and regional structural data to provide a well-constrained deformation history for the feldspar clasts. One hundred and forty-three in-situ 40Ar/39Ar analyses measured using ultraviolet laser ablation record a range of apparent ages (317-1030 Ma). The K-feldspar showing the least strain records the greatest range of apparent ages from 420-1,030 Ma, with the oldest apparent ages being found close to the centre of the feldspar away from fractures and the detrital grain boundary. The most deformed K-feldspar yields the youngest apparent ages (317-453 Ma) but there is no spatial relationship between apparent age and the detrital grain boundary. Within this feldspar, the oldest apparent ages are recorded from orientation domain boundaries and fracture surfaces where an excess or trapped 40Ar component resides. Orientation contrast images at a similar scale to the Ar analyses illustrate a significant deformation-related microstructural difference between the feldspars and we conclude that deformation plays a significant role in controlling Ar systematics of feldspars at both the inter- and intragrain scales even at relatively low

  11. Chemical and physical erosion rhythms of the West African Cenozoic morphogenesis: The 39Ar-40Ar dating of supergene K-Mn oxides

    NASA Astrophysics Data System (ADS)

    Beauvais, Anicet; Ruffet, Gilles; HéNocque, Olivier; Colin, Fabrice

    2008-12-01

    Chemical weathering and mechanical erosion are first-order processes of long-term tropical morphogenesis, which is still poorly deciphered for lack of time constraints. We address this issue by laser probe 39Ar-40Ar dating of generations of cryptomelane [K1-2Mn8O16, nH2O] from the manganese ore deposit of Tambao in northern Burkina Faso. This Mn deposit results from the supergene weathering of carbonate and silicate Mn protores underneath lateritic palaeolandsurfaces. It consists of an upper cryptomelane-rich domain and a lower domain where pyrolusite (β-MnO2) is the dominant Mn oxide. The oldest 39Ar-40Ar ages (59-45 Ma) are obtained on surface outcrops while the youngest ones characterize deep oxidation fronts (3.4-2.9 Ma). Apparent correlations of 39Ar-40Ar age groups with δ18O and eustatic curves allow definition of the different stages of morphogenesis. Paleocene-Eocene ages (59-45 Ma) bracket a greenhouse period propitious to bauxitic weathering. The lack of significant ages between ˜45 and 29 Ma characterizes a period dominated by mechanical erosion, during which detrital sediments, including lateritic materials, were accumulated in intracratonic basins allowing the exhumation of a new lateritic landsurface. Two major weathering periods separated by a second erosion episode (24-18 Ma) are also depicted at the end of Oligocene (29-24 Ma) and lower to mid-Miocene (18-11.5 Ma) in the upper domain, during which newly shaped land surfaces conspicuously weathered. The shorter-weathering and erosion episodes recorded in the lower domain from ˜18 to ˜2.9 Ma led to the final geomorphic changes that were conducive to the formation of glacis. The preservation of old cryptomelane (59-45 Ma) in the upper part of the ore deposit indicates a Cenozoic denudation limited to the erosion of previous bauxites, and partly, of ferricretes.

  12. New 40Ar/ 39Ar dating results from the Shanwang Basin, eastern China: Constraints on the age of the Shanwang Formation and associated biota

    NASA Astrophysics Data System (ADS)

    He, Huaiyu; Deng, Chenglong; Pan, Yongxin; Deng, Tao; Luo, Zhaohua; Sun, Jimin; Zhu, Rixiang

    2011-07-01

    The fluvio-lacustrine sequence of the Shanwang Basin, eastern China, preserves a rich and important terrestrial fossil fauna and flora; the exceptional preservation of these fossils reveals the dynamics of ancient mammalian ecosystems and plant biology. However, the timing of this sedimentary sequence has been the subject of debate for decades. Here we contribute to this debate by presenting the detailed results of 40Ar/ 39Ar analysis of the basalts above, below, and within the Shanwang Formation. These dates place stringent constraints on the age of Shanwang Formation and associated biota. 40Ar/ 39Ar ages obtained from basalts of the Niushan and Yaoshan Formations, which underlie and overlie the Shanwang Formation, are 21.0 ± 2.5 Ma (2σ, full external error) and 17.3 ± 1.5 Ma (2σ, full external error), respectively. The 40Ar/ 39Ar age of the basalt in the Shanwang Formation is 17-18 Ma. Given the age constraints of the basalts of the Yaoshan and Shanwang Formations, the age of the Shanwang biota is estimated to be ca. 17 Ma, late Burdigalian of the Early Miocene, indicating that the deposition of this fauna coincided with the onset of the mid-Miocene Climatic Optimum. The results provide new age constraints on the Shanwang mammal fauna, and independently support interpretations that this fauna can be assigned to chronozone MN4, and correlated with middle Orleanian of the European Land Mammal Age, and to late Hemingfordian of the North American Land Mammal Age. Biological diversity of the Shanwang Formation could reflect the global-scale mid-Miocene Climatic Optimum.

  13. Borrowed alleles and convergence in serpentine adaptation

    PubMed Central

    Arnold, Brian J.; Lahner, Brett; DaCosta, Jeffrey M.; Weisman, Caroline M.; Hollister, Jesse D.; Salt, David E.; Bomblies, Kirsten; Yant, Levi

    2016-01-01

    Serpentine barrens represent extreme hazards for plant colonists. These sites are characterized by high porosity leading to drought, lack of essential mineral nutrients, and phytotoxic levels of metals. Nevertheless, nature forged populations adapted to these challenges. Here, we use a population-based evolutionary genomic approach coupled with elemental profiling to assess how autotetraploid Arabidopsis arenosa adapted to a multichallenge serpentine habitat in the Austrian Alps. We first demonstrate that serpentine-adapted plants exhibit dramatically altered elemental accumulation levels in common conditions, and then resequence 24 autotetraploid individuals from three populations to perform a genome scan. We find evidence for highly localized selective sweeps that point to a polygenic, multitrait basis for serpentine adaptation. Comparing our results to a previous study of independent serpentine colonizations in the closely related diploid Arabidopsis lyrata in the United Kingdom and United States, we find the highest levels of differentiation in 11 of the same loci, providing candidate alleles for mediating convergent evolution. This overlap between independent colonizations in different species suggests that a limited number of evolutionary strategies are suited to overcome the multiple challenges of serpentine adaptation. Interestingly, we detect footprints of selection in A. arenosa in the context of substantial gene flow from nearby off-serpentine populations of A. arenosa, as well as from A. lyrata. In several cases, quantitative tests of introgression indicate that some alleles exhibiting strong selective sweep signatures appear to have been introgressed from A. lyrata. This finding suggests that migrant alleles may have facilitated adaptation of A. arenosa to this multihazard environment. PMID:27357660

  14. Biased gene conversion skews allele frequencies in human populations, increasing the disease burden of recessive alleles.

    PubMed

    Lachance, Joseph; Tishkoff, Sarah A

    2014-10-02

    Gene conversion results in the nonreciprocal transfer of genetic information between two recombining sequences, and there is evidence that this process is biased toward G and C alleles. However, the strength of GC-biased gene conversion (gBGC) in human populations and its effects on hereditary disease have yet to be assessed on a genomic scale. Using high-coverage whole-genome sequences of African hunter-gatherers, agricultural populations, and primate outgroups, we quantified the effects of GC-biased gene conversion on population genomic data sets. We find that genetic distances (FST and population branch statistics) are modified by gBGC. In addition, the site frequency spectrum is left-shifted when ancestral alleles are favored by gBGC and right-shifted when derived alleles are favored by gBGC. Allele frequency shifts due to gBGC mimic the effects of natural selection. As expected, these effects are strongest in high-recombination regions of the human genome. By comparing the relative rates of fixation of unbiased and biased sites, the strength of gene conversion was estimated to be on the order of Nb ≈ 0.05 to 0.09. We also find that derived alleles favored by gBGC are much more likely to be homozygous than derived alleles at unbiased SNPs (+42.2% to 62.8%). This results in a curse of the converted, whereby gBGC causes substantial increases in hereditary disease risks. Taken together, our findings reveal that GC-biased gene conversion has important population genetic and public health implications.

  15. Non-covalent sp(3) carbon bonding with ArCF3 is analogous to CH-π interactions.

    PubMed

    Bauzá, Antonio; Mooibroek, Tiddo J; Frontera, Antonio

    2014-10-28

    A combined CSD and ab initio study reveals that the interaction between the sp(3) C-atom in para-substituted ArCF3 and electron rich atoms is weak (<5 kcal mol(−1)), somewhat directional, and thus comparable to CH–π interactions.

  16. The bond-forming reactions of atomic dications with neutral molecules: formation of ArNH+ and ArN+ from collisions of Ar2+ with NH3.

    PubMed

    Lambert, Natalie; Kearney, Dominic; Kaltsoyannis, Nikolas; Price, Stephen D

    2004-03-24

    An experimental and computational study has been performed to investigate the bond-forming reactivity between Ar(2+) and NH(3). Experimentally, we detect two previously unobserved bond-forming reactions between Ar(2+) and NH(3) forming ArN(+) and ArNH(+). This is the first experimental observation of a triatomic product ion (ArNH(+)) following a chemical reaction of a rare gas dication with a neutral. The intensity of ArNH(+) was found to decrease with increasing collision energy, with a corresponding increase in the intensity of ArN(+), indicating that ArN(+) is formed by the dissociation of ArNH(+). Key features on the potential energy surface for the reaction were calculated quantum chemically using CASSCF and MRCI methods. The calculated reaction mechanism, which takes place on a singlet surface, involves the initial formation of an Ar-N bond to give Ar-NH(3)(2+). This complexation is followed by proton loss via a transition state, and then loss of the two remaining hydrogen atoms in two subsequent activationless steps to give the products (3)ArN(+) + H(+) + 2H. This calculated pathway supports the sequential formation of ArN(+) from ArNH(+), as suggested by the experimental data. The calculations also indicate that no bond-forming pathway exists on the ground triplet surface for this system.

  17. Allelic genealogies in sporophytic self-incompatibility systems in plants.

    PubMed Central

    Schierup, M H; Vekemans, X; Christiansen, F B

    1998-01-01

    Expectations for the time scale and structure of allelic genealogies in finite populations are formed under three models of sporophytic self-incompatibility. The models differ in the dominance interactions among the alleles that determine the self-incompatibility phenotype: In the SSIcod model, alleles act codominantly in both pollen and style, in the SSIdom model, alleles form a dominance hierarchy, and in SSIdomcod, alleles are codominant in the style and show a dominance hierarchy in the pollen. Coalescence times of alleles rarely differ more than threefold from those under gametophytic self-incompatibility, and transspecific polymorphism is therefore expected to be equally common. The previously reported directional turnover process of alleles in the SSIdomcod model results in coalescence times lower and substitution rates higher than those in the other models. The SSIdom model assumes strong asymmetries in allelic action, and the most recessive extant allele is likely to be the most recent common ancestor. Despite these asymmetries, the expected shape of the allele genealogies does not deviate markedly from the shape of a neutral gene genealogy. The application of the results to sequence surveys of alleles, including interspecific comparisons, is discussed. PMID:9799270

  18. Identification of an AR Mutation-Negative Class of Androgen Insensitivity by Determining Endogenous AR Activity

    PubMed Central

    Ukat, M.; Schweikert, H. U.; Hiort, O.; Werner, R.; Drop, S. L. S.; Cools, M.; Hughes, I. A.; Audi, L.; Ahmed, S. F.; Demiri, J.; Rodens, P.; Worch, L.; Wehner, G.; Kulle, A. E.; Dunstheimer, D.; Müller-Roßberg, E.; Reinehr, T.; Hadidi, A. T.; Eckstein, A. K.; van der Horst, C.; Seif, C.; Siebert, R.; Ammerpohl, O.; Holterhus, P.-M.

    2016-01-01

    Context: Only approximately 85% of patients with a clinical diagnosis complete androgen insensitivity syndrome and less than 30% with partial androgen insensitivity syndrome can be explained by inactivating mutations in the androgen receptor (AR) gene. Objective: The objective of the study was to clarify this discrepancy by in vitro determination of AR transcriptional activity in individuals with disorders of sex development (DSD) and male controls. Design: Quantification of DHT-dependent transcriptional induction of the AR target gene apolipoprotein D (APOD) in cultured genital fibroblasts (GFs) (APOD assay) and next-generation sequencing of the complete coding and noncoding AR locus. Setting: The study was conducted at a university hospital endocrine research laboratory. Patients: GFs from 169 individuals were studied encompassing control males (n = 68), molecular defined DSD other than androgen insensitivity syndrome (AIS; n = 18), AR mutation-positive AIS (n = 37), and previously undiagnosed DSD including patients with a clinical suspicion of AIS (n = 46). Intervention(s): There were no interventions. Main Outcome Measure(s): DHT-dependent APOD expression in cultured GF and AR mutation status in 169 individuals was measured. Results: The APOD assay clearly separated control individuals (healthy males and molecular defined DSD patients other than AIS) from genetically proven AIS (cutoff < 2.3-fold APOD-induction; 100% sensitivity, 93.3% specificity, P < .0001). Of 46 DSD individuals with no AR mutation, 17 (37%) fell below the cutoff, indicating disrupted androgen signaling. Conclusions: AR mutation-positive AIS can be reliably identified by the APOD assay. Its combination with next-generation sequencing of the AR locus uncovered an AR mutation-negative, new class of androgen resistance, which we propose to name AIS type II. Our data support the existence of cellular components outside the AR affecting androgen signaling during sexual differentiation with high

  19. Excess Ar-40 in the Zagami Shergottite: Does It Reveal Crystallization History?

    NASA Technical Reports Server (NTRS)

    Bogard, Donald D.; Park, Jisun

    2007-01-01

    The Zagami basaltic shergottite has fine- and coarse-grained (FG & CG) areas, which may reflect partial crystallization in a deep, slowly cooled magma chamber to form Mg-rich pyroxene cores, followed by entrainment of these crystals into a magma that rose and crystallized near the surface. Late-stage melt pockets formed mesostasis and feldspar (maskelynite) having a range of compositions, but low water abundance. Higher I(sub Sr) in the FG portion may result from the second stage having incorporated old crustal rocks that failed to reach isotopic equilibrium. Zagami, like other shergottites, contains excess Ar-40(sub xs) beyond that expected from internal decay of K-40 during its Sm-Nd age of 177 Myr. We suggest that at least a portion of this Ar-40(sub xs) in Zagami and some other shergottites was inherited from the magma, much as is the case of MORBs on Earth. We made Ar-39-Ar-40 age determinations on feldspar and pyroxene separates from both the FG and CG portions of Zagami. If Zagami experienced an evolving fractional crystallization history, including possible crustal contamination of the magma, that might be indicated in differing amounts of Ar-40(sub xs) between mineral phases and between FG and CG portions.

  20. Discordant K-Ar and young exposure dates for the Windjana sandstone, Kimberley, Gale Crater, Mars

    NASA Astrophysics Data System (ADS)

    Vasconcelos, P. M.; Farley, K. A.; Malespin, C. A.; Mahaffy, P.; Ming, D.; McLennan, S. M.; Hurowitz, J. A.; Rice, Melissa S.

    2016-10-01

    K-Ar and noble gas surface exposure age measurements were carried out on the Windjana sandstone, Kimberley region, Gale Crater, Mars, by using the Sample Analysis at Mars instrument on the Curiosity rover. The sandstone is unusually rich in sanidine, as determined by CheMin X-ray diffraction, contributing to the high K2O concentration of 3.09 ± 0.20 wt % measured by Alpha-Particle X-ray Spectrometer analysis. A sandstone aliquot heated to 915°C yielded a K-Ar age of 627 ± 50 Ma. Reheating this aliquot yielded no additional Ar. A second aliquot heated in the same way yielded a much higher K-Ar age of 1710 ± 110 Ma. These data suggest incomplete Ar extraction from a rock with a K-Ar age older than 1710 Ma. Incomplete extraction at 900°C is not surprising for a rock with a large fraction of K carried by Ar-retentive K-feldspar. Likely, variability in the exact temperature achieved by the sample from run to run, uncertainties in sample mass estimation, and possible mineral fractionation during transport and storage prior to analysis may contribute to these discrepant data. Cosmic ray exposure ages from 3He and 21Ne in the two aliquots are minimum values given the possibility of incomplete extraction. However, the general similarity between the 3He (57 ± 49 and 18 ± 32 Ma, mean 30 Ma) and 21Ne (2 ± 32 and 83 ± 24 Ma, mean 54 Ma) exposure ages provides no evidence for underextraction. The implied erosion rate at the Kimberley location is similar to that reported at the nearby Yellowknife Bay outcrop.

  1. Exquisite allele discrimination by toehold hairpin primers

    PubMed Central

    Byrom, Michelle; Bhadra, Sanchita; Jiang, Yu Sherry; Ellington, Andrew D.

    2014-01-01

    The ability to detect and monitor single nucleotide polymorphisms (SNPs) in biological samples is an enabling research and clinical tool. We have developed a surprising, inexpensive primer design method that provides exquisite discrimination between SNPs. The field of DNA computation is largely reliant on using so-called toeholds to initiate strand displacement reactions, leading to the execution of kinetically trapped circuits. We have now similarly found that the short toehold sequence to a target of interest can initiate both strand displacement within the hairpin and extension of the primer by a polymerase, both of which will further stabilize the primer:template complex. However, if the short toehold does not bind, neither of these events can readily occur and thus amplification should not occur. Toehold hairpin primers were used to detect drug resistance alleles in two genes, rpoB and katG, in the Mycobacterium tuberculosis genome, and ten alleles in the Escherichia coli genome. During real-time PCR, the primers discriminate between mismatched templates with Cq delays that are frequently so large that the presence or absence of mismatches is essentially a ‘yes/no’ answer. PMID:24990378

  2. ArsP: a methylarsenite efflux permease

    PubMed Central

    Chen, Jian; Madegowda, Mahendra; Bhattacharjee, Hiranmoy; Rosen, Barry P.

    2015-01-01

    Trivalent organoarsenic compounds are far more toxic than either pentavalent organoarsenicals or inorganic arsenite. Many microbes methylate inorganic arsenite (As(III)) to more toxic and carcinogenic methylarsenite (MAs(III)). Additionally, monosodium methylarsenate (MSMA or MAs(V)) has been used widely as an herbicide and is reduced by microbial communities to MAs(III). Roxarsone (3-nitro-4-hydroxybenzenearsonic acid) is a pentavalent aromatic arsenical that is used as antimicrobial growth promoter for poultry and swine, and its active form is the trivalent species Rox(III). A bacterial permease, ArsP, from Campylobacter jejuni, was recently shown to confer resistance to roxarsone. In this study C. jejuni arsP was expressed in Escherichia coli and shown to confer resistance to MAs(III) and Rox(III) but not to inorganic As(III) or pentavalent organoarsenicals. Cells of E. coli expressing arsP did not accumulate trivalent organoarsenicals. Everted membrane vesicles from those cells accumulated MAs(III)>Rox(III) with energy supplied by NADH oxidation, reflecting efflux from cells. The vesicles did not transport As(III), MAs(V) or pentavalent roxarsone. Mutation or modification of the two conserved cysteine residues resulted in loss of transport activity, suggesting that they play a role in ArsP function. Thus ArsP is the first identified efflux system specific for trivalent organoarsenicals. PMID:26234817

  3. Correlation diagrams in 40 Ar/39Ar dating: is there a correct choice?

    USGS Publications Warehouse

    Dalrymple, G.B.; Lanphere, M.A.; Pringle, M.S.

    1988-01-01

    Contrary to published assertions, the 2 types of correlation diagrams used in the interpretation of 40Ar/39Ar incremental-heating data yield the same information provided the correct mathematics are used for estimating correlation coefficients and for the least squares fit. The choice is simply between 2 illustrative, graphical displays, neither of which is fundamentally superior to the other. -Authors

  4. Allelic barley MLA immune receptors recognize sequence-unrelated avirulence effectors of the powdery mildew pathogen

    PubMed Central

    Lu, Xunli; Kracher, Barbara; Saur, Isabel M. L.; Bauer, Saskia; Ellwood, Simon R.; Wise, Roger; Yaeno, Takashi; Maekawa, Takaki; Schulze-Lefert, Paul

    2016-01-01

    Disease-resistance genes encoding intracellular nucleotide-binding domain and leucine-rich repeat proteins (NLRs) are key components of the plant innate immune system and typically detect the presence of isolate-specific avirulence (AVR) effectors from pathogens. NLR genes define the fastest-evolving gene family of flowering plants and are often arranged in gene clusters containing multiple paralogs, contributing to copy number and allele-specific NLR variation within a host species. Barley mildew resistance locus a (Mla) has been subject to extensive functional diversification, resulting in allelic resistance specificities each recognizing a cognate, but largely unidentified, AVRa gene of the powdery mildew fungus, Blumeria graminis f. sp. hordei (Bgh). We applied a transcriptome-wide association study among 17 Bgh isolates containing different AVRa genes and identified AVRa1 and AVRa13, encoding candidate-secreted effectors recognized by Mla1 and Mla13 alleles, respectively. Transient expression of the effector genes in barley leaves or protoplasts was sufficient to trigger Mla1 or Mla13 allele-specific cell death, a hallmark of NLR receptor-mediated immunity. AVRa1 and AVRa13 are phylogenetically unrelated, demonstrating that certain allelic MLA receptors evolved to recognize sequence-unrelated effectors. They are ancient effectors because corresponding loci are present in wheat powdery mildew. AVRA1 recognition by barley MLA1 is retained in transgenic Arabidopsis, indicating that AVRA1 directly binds MLA1 or that its recognition involves an evolutionarily conserved host target of AVRA1. Furthermore, analysis of transcriptome-wide sequence variation among the Bgh isolates provides evidence for Bgh population structure that is partially linked to geographic isolation. PMID:27702901

  5. Microsatellite variation and rare alleles in a bottlenecked Hawaiian Islands endemic: implications for reintroductions

    USGS Publications Warehouse

    Reynolds, Michelle H.; Pearce, John M.; Lavretsky, Philip; Seixas, Pedro P.; Courtot, Karen

    2015-01-01

    Conservation of genetic biodiversity in endangered wildlife populations is an important challenge to address since the loss of alleles and genetic drift may influence future adaptability. Reintroduction aims to re-establish species to restored or protected ecosystems; however, moving a subset of individuals may result in loss of gene variants during the management-induced bottleneck (i.e. translocation). The endangered Laysan teal Anas laysanensis was once widespread across the Hawaiian archipelago, but became isolated on Laysan Island (415 ha) from the mid-1800s until 2004 when a translocation to Midway Atoll (596 ha) was undertaken to reduce extinction risks. We compared genetic diversity and quantified variation at microsatellite loci sampled from 230 individuals from the wild populations at Laysan (1999 to 2009) and Midway (2007 to 2010; n = 133 Laysan, n = 96 Midway birds). We identified polymorphic markers by screening nuclear microsatellites (N = 83). Low nuclear variation was detected, consistent with the species’ insular isolation and historical bottleneck. Six of 83 microsatellites were polymorphic. We found limited but similar estimates of allelic richness (2.58 alleles per locus) and heterozygosity within populations. However, 2 rare alleles found in the Laysan source population were not present in Midway’s reintroduced population, and a unique allele was discovered in an individual on Midway. Differentiation between island populations was low (FST = 0.6%), but statistically significant. Our results indicate that genetic drift had little effect on offspring generations 3 to 6 yr post-release and demonstrate the utility of using known founder events to help quantify genetic capture during translocations and to inform management decisions.

  6. Allelic barley MLA immune receptors recognize sequence-unrelated avirulence effectors of the powdery mildew pathogen.

    PubMed

    Lu, Xunli; Kracher, Barbara; Saur, Isabel M L; Bauer, Saskia; Ellwood, Simon R; Wise, Roger; Yaeno, Takashi; Maekawa, Takaki; Schulze-Lefert, Paul

    2016-10-18

    Disease-resistance genes encoding intracellular nucleotide-binding domain and leucine-rich repeat proteins (NLRs) are key components of the plant innate immune system and typically detect the presence of isolate-specific avirulence (AVR) effectors from pathogens. NLR genes define the fastest-evolving gene family of flowering plants and are often arranged in gene clusters containing multiple paralogs, contributing to copy number and allele-specific NLR variation within a host species. Barley mildew resistance locus a (Mla) has been subject to extensive functional diversification, resulting in allelic resistance specificities each recognizing a cognate, but largely unidentified, AVRa gene of the powdery mildew fungus, Blumeria graminis f. sp. hordei (Bgh). We applied a transcriptome-wide association study among 17 Bgh isolates containing different AVRa genes and identified AVRa1 and AVRa13, encoding candidate-secreted effectors recognized by Mla1 and Mla13 alleles, respectively. Transient expression of the effector genes in barley leaves or protoplasts was sufficient to trigger Mla1 or Mla13 allele-specific cell death, a hallmark of NLR receptor-mediated immunity. AVRa1 and AVRa13 are phylogenetically unrelated, demonstrating that certain allelic MLA receptors evolved to recognize sequence-unrelated effectors. They are ancient effectors because corresponding loci are present in wheat powdery mildew. AVRA1 recognition by barley MLA1 is retained in transgenic Arabidopsis, indicating that AVRA1 directly binds MLA1 or that its recognition involves an evolutionarily conserved host target of AVRA1 Furthermore, analysis of transcriptome-wide sequence variation among the Bgh isolates provides evidence for Bgh population structure that is partially linked to geographic isolation.

  7. Deleterious alleles in the human genome are on average younger than neutral alleles of the same frequency.

    PubMed

    Kiezun, Adam; Pulit, Sara L; Francioli, Laurent C; van Dijk, Freerk; Swertz, Morris; Boomsma, Dorret I; van Duijn, Cornelia M; Slagboom, P Eline; van Ommen, G J B; Wijmenga, Cisca; de Bakker, Paul I W; Sunyaev, Shamil R

    2013-01-01

    Large-scale population sequencing studies provide a complete picture of human genetic variation within the studied populations. A key challenge is to identify, among the myriad alleles, those variants that have an effect on molecular function, phenotypes, and reproductive fitness. Most non-neutral variation consists of deleterious alleles segregating at low population frequency due to incessant mutation. To date, studies characterizing selection against deleterious alleles have been based on allele frequency (testing for a relative excess of rare alleles) or ratio of polymorphism to divergence (testing for a relative increase in the number of polymorphic alleles). Here, starting from Maruyama's theoretical prediction (Maruyama T (1974), Am J Hum Genet USA 6:669-673) that a (slightly) deleterious allele is, on average, younger than a neutral allele segregating at the same frequency, we devised an approach to characterize selection based on allelic age. Unlike existing methods, it compares sets of neutral and deleterious sequence variants at the same allele frequency. When applied to human sequence data from the Genome of the Netherlands Project, our approach distinguishes low-frequency coding non-synonymous variants from synonymous and non-coding variants at the same allele frequency and discriminates between sets of variants independently predicted to be benign or damaging for protein structure and function. The results confirm the abundance of slightly deleterious coding variation in humans.

  8. Microarrays for high-throughput genotyping of MICA alleles using allele-specific primer extension.

    PubMed

    Baek, I C; Jang, J-P; Choi, H-B; Choi, E-J; Ko, W-Y; Kim, T-G

    2013-10-01

    The role of major histocompatibility complex (MHC) class I chain-related gene A (MICA), a ligand of NKG2D, has been defined in human diseases by its allele associations with various autoimmune diseases, hematopoietic stem cell transplantation (HSCT) and cancer. This study describes a practical system to develop MICA genotyping by allele-specific primer extension (ASPE) on microarrays. From the results of 20 control primers, strict and reliable cut-off values of more than 30,000 mean fluorescence intensity (MFI) as positive and less than 3000 MFI as negative, were applied to select high-quality specific extension primers. Among 55 allele-specific primers, 44 primers could be initially selected as optimal primer. Through adjusting the length, six primers were improved. The other failed five primers were corrected by refractory modification. MICA genotypes by ASPE on microarrays showed the same results as those by nucleotide sequencing. On the basis of these results, ASPE on microarrays may provide high-throughput genotyping for MICA alleles for population studies, disease-gene associations and HSCT.

  9. Hazard evaluation for 244-AR vault facility

    SciTech Connect

    BRAUN, D.J.

    1999-08-25

    This document presents the results of a hazard identification and evaluation performed on the 244-AR Vault Facility to close a USQ (USQ No.TF-98-0785, Potential Inadequacy in Authorization Basis (PIAB): To Evaluate Miscellaneous Facilities Listed In HNF-2503 And Not Addressed In The TWRS Authorization Basis) that was generated as part of an evaluation of inactive TWRS facilities. A hazard evaluation for the Hanford Site 244-AR Vault Facility was performed. The process and results of the hazard evaluation are provided in this document. A previous hazard evaluation was performed for the 244-AR Vault Facility in 1996 in support of the Basis for Interim Operation (BIO) (HNF-SD-WM-BIO-001, 1998, Revision 1) of the Tank Waste Remediation System (TWRS). The results of that evaluation are provided in the BIO. Upon review of those results it was determined that hazardous conditions that could lead to the release of radiological and toxicological material from the 244-AR vaults due to flooding was not addressed in the original hazards evaluation. This supplemental hazard evaluation addresses this oversight of the original hazard evaluation. The results of the hazard evaluation were compared to the current TWRS BIO to identify any hazardous conditions where Authorization Basis (AB) controls may not be sufficient or may not exist. This document is not part of the AB and is not a vehicle for requesting changes to the AB. It is only intended to provide information about hazardous conditions associated with the condition and configuration of the 244-AR vault facility. The AB Control Decision process could be used to determine the applicability and adequacy of existing AB controls as well as any new controls that may be needed for the identified hazardous conditions associated with 244-AR vault flooding. This hazard evaluation does not constitute an accident analysis.

  10. Timing of Hydrocarbon Fluid Emplacement in Sandstone Reservoirs in Neogene in Huizhou Sag, Southern China Sea, by Authigenic Illite 40Ar- 39Ar Laser Stepwise Heating

    NASA Astrophysics Data System (ADS)

    Hesheng, Shi; Junzhang, Zhu; Huaning, Qiu; yu, Shu; Jianyao, Wu; Zulie, Long

    Timing of oil or gas emplacements is a new subject in isotopic geochronology and petroleum geology. Hamilton et al. expounded the principle of the illite K-Ar age: Illite is often the last or one of the latest mineral cements to form prior to hydrocarbon accumulation. Since the displacement of formation water by hydrocarbons will cause silicate diagenesis to cease, K-Ar ages for illite will constrain the timing of this event, and also constrain the maximum age of formation of the trap structure. In this study, the possibility of authigenic illites 40Ar- 39Ar dating has been investigated. The illite samples were separated from the Tertiary sandstones in three rich oil reservoir belts within the Huizhou sag by cleaning, fracturing by cycled cooling-heating, soxhlet-extraction with solvents of benzene and methanol and separating with centrifugal machine. If oil is present in the separated samples, ionized organic fragments with m/e ratios of 36 to 40 covering the argon isotopes will be yielded by the ion source of a mass spectrometer, resulting in wrong argon isotopic analyses and wrong 40Ar- 39Ar ages. The preliminary experiments of illite by heating did show the presence of ionized organic fragments with m/e ratios of 36 to 44. In order to clean up the organic gases completely and obtain reliable analysis results, a special purification apparatus has been established by Qiu et al. and proved valid by the sequent illite analyses. All the illite samples by 40Ar- 39Ar IR-laser stepwise heating yield stair-up age spectra in lower laser steps and plateaux in higher laser steps. The youngest apparent ages corresponding to the beginning steps are reasonable to be interpreted for the hydrocarbon accumulation ages. The weighted mean ages of the illites from the Zhuhai and Zhujiang Formations are (12.1 ± 1.1) Ma and (9.9 ± 1.2) Ma, respectively. Therefore, the critical emplacement of petroleum accumulation in Zhujiang Formation in Huizhou sag took place in ca 10 Ma. Late

  11. Use of allele scores as instrumental variables for Mendelian randomization

    PubMed Central

    Burgess, Stephen; Thompson, Simon G

    2013-01-01

    Background An allele score is a single variable summarizing multiple genetic variants associated with a risk factor. It is calculated as the total number of risk factor-increasing alleles for an individual (unweighted score), or the sum of weights for each allele corresponding to estimated genetic effect sizes (weighted score). An allele score can be used in a Mendelian randomization analysis to estimate the causal effect of the risk factor on an outcome. Methods Data were simulated to investigate the use of allele scores in Mendelian randomization where conventional instrumental variable techniques using multiple genetic variants demonstrate ‘weak instrument’ bias. The robustness of estimates using the allele score to misspecification (for example non-linearity, effect modification) and to violations of the instrumental variable assumptions was assessed. Results Causal estimates using a correctly specified allele score were unbiased with appropriate coverage levels. The estimates were generally robust to misspecification of the allele score, but not to instrumental variable violations, even if the majority of variants in the allele score were valid instruments. Using a weighted rather than an unweighted allele score increased power, but the increase was small when genetic variants had similar effect sizes. Naive use of the data under analysis to choose which variants to include in an allele score, or for deriving weights, resulted in substantial biases. Conclusions Allele scores enable valid causal estimates with large numbers of genetic variants. The stringency of criteria for genetic variants in Mendelian randomization should be maintained for all variants in an allele score. PMID:24062299

  12. Preservation of ancient impact ages on the R chondrite parent body: 40Ar/39Ar age of hornblende-bearing R chondrite LAP 04840

    USGS Publications Warehouse

    Righter, Kevin; Cosca, Michael A.; Morgan, Leah

    2016-01-01

    The hornblende- and biotite-bearing R chondrite LAP 04840 is a rare kind of meteorite possibly containing outer solar system water stored during metamorphism or postshock annealing deep within an asteroid. Because little is known regarding its age and origin, we determined 40Ar/39Ar ages on hornblende-rich separates of the meteorite, and obtained plateau ages of 4340(±40) to 4380(±30) Ma. These well-defined plateau ages, coupled with evidence for postshock annealing, indicate this meteorite records an ancient shock event and subsequent annealing. The age of 4340–4380 Ma (or 4.34–4.38 Ga) for this and other previously dated R chondrites is much older than most impact events recorded by ordinary chondrites and points to an ancient event or events that predated the late heavy bombardment that is recorded in so many meteorites and lunar samples.

  13. 76 FR 27077 - Agency Information Collection Activities: Form AR-11 and Form AR-11SR, Extension of an Existing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-10

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form AR-11 and Form AR- 11SR, Extension of an Existing Information Collection; Comment Request ACTION: 60-Day Notice of Information Collection under Review: Form AR- 11 and Form AR-11SR, Alien's Change of Address...

  14. Allele-specific disparity in breast cancer

    PubMed Central

    2011-01-01

    Background In a cancer cell the number of copies of a locus may vary due to amplification and deletion and these variations are denoted as copy number alterations (CNAs). We focus on the disparity of CNAs in tumour samples, which were compared to those in blood in order to identify the directional loss of heterozygosity. Methods We propose a numerical algorithm and apply it to data from the Illumina 109K-SNP array on 112 samples from breast cancer patients. B-allele frequency (BAF) and log R ratio (LRR) of Illumina were used to estimate Euclidian distances. For each locus, we compared genotypes in blood and tumour for subset of samples being heterozygous in blood. We identified loci showing preferential disparity from heterozygous toward either the A/B-allele homozygous (allelic disparity). The chi-squared and Cochran-Armitage trend tests were used to examine whether there is an association between high levels of disparity in single nucleotide polymorphisms (SNPs) and molecular, clinical and tumour-related parameters. To identify pathways and network functions over-represented within the resulting gene sets, we used Ingenuity Pathway Analysis (IPA). Results To identify loci with a high level of disparity, we selected SNPs 1) with a substantial degree of disparity and 2) with substantial frequency (at least 50% of the samples heterozygous for the respective locus). We report the overall difference in disparity in high-grade tumours compared to low-grade tumours (p-value < 0.001) and significant associations between disparity in multiple single loci and clinical parameters. The most significantly associated network functions within the genes represented in the loci of disparity were identified, including lipid metabolism, small-molecule biochemistry, and nervous system development and function. No evidence for over-representation of directional disparity in a list of stem cell genes was obtained, however genes appeared to be more often altered by deletion than by

  15. Ar-Ar and I-Xe Ages and the Thermal History of IAB Meteorites

    NASA Technical Reports Server (NTRS)

    Bogard, Donald D.; Garrison, Daniel H.; Takeda, Hiroshi

    2005-01-01

    Studies of several samples of the large Caddo County IAB iron meteorite reveal andesitic material, enriched in Si, Na, Al and Ca, which is essentially unique among meteorites. This material is believed to have formed from a chondritic source by partial melting and to have further segregated by grain coarsening. Such an origin implies extended metamorphism of the IAB parent body. New Ar-39- Ar-40 ages for silicate from three different Caddo samples are consistent with a common age of 4.50-4.51 Gyr ago. Less well defined Ar-Ar degassing ages for inclusions from two other IABs, EET8333 and Udei Station, are approx.4.32 Gyr, whereas the age for Campo del Cielo varies considerably over approx.3.23-4.56 Gyr. New I-129-Xe-129 ages for Caddo County and EET8333 are 4557.9+/-0.1 Myr and 4557-4560 Myr, respectively, relative to an age of 4562.3 Myr for Shallowater. Considering all reported Ar-Ar degassing ages for IABs and related winonaites, the range is approx.4.32-4.53 Gyr, but several IABs give similar Ar ages of 4.50-4.52 Gyr. We interpret these older Ar ages to represent cooling after the time of last significant metamorphism on the parent body, and the younger ages to represent later 40Ar diffusion loss. The older Ar-Ar ages for IABs are similar to Sm-Nd and Rb-Sr isochron ages reported in the literature for Caddo County. Considering the possibility that IAB parent body formation was followed by impact disruption, reassembly, and metamorphism (e.g., Benedix et al. 2000), the Ar-Ar ages and IAB cooling rates deduced from Ni concentration profiles in IAB metal (Herpfer et al., 1994) are consistent if the time of the post-assembly metamorphism was as late as approx.4.53 Gyr ago. However, I-Xe ages reported for some IABs define much older ages of approx.4558-4566 Myr, which cannot easily be reconciled with the much younger Ar-Ar and Sm-Nd ages. An explanation for the difference in radiometric ages of IABs may reside in combinations of the following: a) I-Xe ages have very

  16. The CBM RICH detector

    NASA Astrophysics Data System (ADS)

    Adamczewski-Musch, J.; Akishin, P.; Becker, K.-H.; Belogurov, S.; Bendarouach, J.; Boldyreva, N.; Chernogorov, A.; Deveaux, C.; Dobyrn, V.; Dürr, M.; Eschke, J.; Förtsch, J.; Heep, J.; Höohne, C.; Kampert, K.-H.; Kochenda, L.; Kopfer, J.; Kravtsov, P.; Kres, I.; Lebedev, S.; Lebedeva, E.; Leonova, E.; Linev, S.; Mahmoud, T.; Michel, J.; Miftakhov, N.; Niebur, W.; Ovcharenko, E.; Pauly, C.; Pfeifer, D.; Querchfeld, S.; Rautenberg, J.; Reinecke, S.; Riabov, Y.; Roshchin, E.; Samsonov, V.; Tarasenkova, O.; Traxler, M.; Ugur, C.; Vznuzdaev, E.; Vznuzdaev, M.

    2016-05-01

    The CBM RICH detector will use CO2 as radiator gas, focussing glass mirrors with Al+MgF2 reflective and protective coating and Hamamatsu H12700 MAPMTs as photon detectors. The detector will serve for electron to pion separation up to momenta of 8 GeV/c and thus enable in CBM the measurement of electromagnetic radiation from the early and dense fireball in A+A collisions at SIS 100. In this article, the current status of the CBM RICH development will be presented including new measurements of the radiation hardness of the H12700 MAPMT and WLS coatings with p-terphenyl, the new concept for the readout electronics, and optimizations ongoing with respect to the mirror mount structure and overall geometry. Prior to the usage in CBM, part of the already ordered MAPMTs will be used to upgrade the HADES RICH detector for a new measurement campaign at SIS 18 from 2018-2020.

  17. 40Ar/39Ar and K/Ar dating of low grade metamorphism: examples on metabasites from Central Chile

    NASA Astrophysics Data System (ADS)

    Aguirre, L.; Feraud, G.; Fuentes, F.; Delbar, M.; Morata, D.

    2003-04-01

    Dating low to very low-grade burial metamorphic assemblages is often difficult because of (1) few mineral phases compositionally suitable to apply the 40Ar/39Ar and K-Ar methods, and (2) small amount in which these phases are commonly found. K-feldspar adularia, sericitic mica, and celadonite are the best known K-bearing secondary minerals. We present some successful attempts to analyse two distinct secondary phases from a same volcanic formation that allow to test the validity of the measured ages. These ages have been also compared with the crystallisation age of the volcanic rocks in which the secondary phases were lately developed. Adularia and sericite were selected from basic lava flows from a 3 to 13 km thick Cretaceous sequence from the Coastal Range of central Chile, at two different locations: the Bustamante Hill (west from Santiago), and the Cordón de Chacana, c. 80 km further north. Adularia came from a low-variance assemblage with pumpellyite, chlorite and low-albite contained in amygdules whereas sericite was present in milky-white strongly sericitized plagioclase crystals. While small clusters of rare fresh plagioclase grains from lava flows from Bustamante and Chacana displayed concordant plateau ages 119.4 ± 2.4 (2 sigma) and 118.7 ± 0.6 Ma, respectively, the adularia from the same formations gave sensibly younger ages around 94 Ma (high temperature steps), and 96.8 ± 0.2 Ma (plateau age) in Bustamante and Chacana, respectively. Sericite ages were measured in situ into single crystals of strongly transformed plagioclases. The relative proportion of sericite and plagioclase corresponding to each degasing step was monitored by measuring the Ca/K ratio (deduced from 37ArCa/39Ar_K). While intermediate ages were measured on some sericite of both sites (corresponding to a variable but permanent contribution of plagioclase on each step), a plateau age of 97.0 ± 1.6 Ma (concordant with adularia) could be obtained on a strongly sericitized plagioclase

  18. Hydrogen rich gas generator

    NASA Technical Reports Server (NTRS)

    Houseman, J.; Rupe, J. H.; Kushida, R. O. (Inventor)

    1976-01-01

    A process and apparatus is described for producing a hydrogen rich gas by injecting air and hydrocarbon fuel at one end of a cylindrically shaped chamber to form a mixture and igniting the mixture to provide hot combustion gases by partial oxidation of the hydrocarbon fuel. The combustion gases move away from the ignition region to another region where water is injected to be turned into steam by the hot combustion gases. The steam which is formed mixes with the hot gases to yield a uniform hot gas whereby a steam reforming reaction with the hydrocarbon fuel takes place to produce a hydrogen rich gas.

  19. The Effects of Androgens on Murine Cortical Bone Do Not Require AR or ERα Signaling in Osteoblasts and Osteoclasts.

    PubMed

    Ucer, Serra; Iyer, Srividhya; Bartell, Shoshana M; Martin-Millan, Marta; Han, Li; Kim, Ha-Neui; Weinstein, Robert S; Jilka, Robert L; O'Brien, Charles A; Almeida, Maria; Manolagas, Stavros C

    2015-07-01

    In men, androgens are critical for the acquisition and maintenance of bone mass in both the cortical and cancellous bone compartment. Male mice with targeted deletion of the androgen receptor (AR) in mature osteoblasts or osteocytes have lower cancellous bone mass, but no cortical bone phenotype. We have investigated the possibility that the effects of androgens on the cortical compartment result from AR signaling in osteoprogenitors or cells of the osteoclast lineage; or via estrogen receptor alpha (ERα) signaling in either or both of these two cell types upon conversion of testosterone to estradiol. To this end, we generated mice with targeted deletion of an AR or an ERα allele in the mesenchymal (AR(f/y);Prx1-Cre or ERα(f/f);Osx1-Cre) or myeloid cell lineage (AR(f/y);LysM-Cre or ERα(f/f);LysM-Cre) and their descendants. Male AR(f/y);Prx1-Cre mice exhibited decreased bone volume and trabecular number, and increased osteoclast number in the cancellous compartment. Moreover, they did not undergo the loss of cancellous bone volume and trabecular number caused by orchidectomy (ORX) in their littermate controls. In contrast, AR(f/y);LysM-Cre, ERα(f/f);Osx1-Cre, or ERα(f/f);LysM-Cre mice had no cancellous bone phenotype at baseline and lost the same amount of cancellous bone as their controls following ORX. Most unexpectedly, adult males of all four models had no discernible cortical bone phenotype at baseline, and lost the same amount of cortical bone as their littermate controls after ORX. Recapitulation of the effects of ORX by AR deletion only in the AR(f/y);Prx1-Cre mice indicates that the effects of androgens on cancellous bone result from AR signaling in osteoblasts-not on osteoclasts or via aromatization. The effects of androgens on cortical bone mass, on the other hand, do not require AR or ERα signaling in any cell type across the osteoblast or osteoclast differentiation lineage. Therefore, androgens must exert their effects indirectly by actions on

  20. Ar-40/Ar-39 Ages of Maskelynite Grains from ALHA 77005

    NASA Technical Reports Server (NTRS)

    Turrin, B.; Park, J.; Herzog, G. F.; Lindsay, F. N.; Delaney, J. S.; Nyquist, L. E.; Swisher, C., III

    2013-01-01

    We present Ar-40/Ar-39 measurements for twelve small (20-60 micro-g) maskelynite samples from the heavily shocked martian meteorite ALHA 77005. The reported modal composition for ALHA 77005 is 50-60% olivine (Fa28), 30-40% pyroxene (Wo5Fs23En72), approx.8% maskelynite (An53), and approx.2% opaques by volume [1]). The meteorite is usually classified as a lherzolite. Previous Studies - Ar-40/Ar-39 results from previous work display disturbed release spectra [2,3]. In study [2], Ar-40/Ar-39 measurements on a 52-mg whole-rock sample produced an extremely disturbed release spec-trum, with all calculated apparent ages > 1 Ga, (Fig. 1). In a subsequent study [3], a light and a dark phase were analyzed. A 2.3-mg sample of the light, relatively low-K phase produced a disturbed release spectrum. For the first 20% of the Ar-39(sub K), most of the apparent ages exceeded >1 Ga; the remaining 80% yielded ages between 0.3-0.5 Ga. The integrated age for this phase is 0.9 Ga.

  1. Ar-Ar Impact Heating Ages of Eucrites and Timing of the LHB

    NASA Technical Reports Server (NTRS)

    Bogard, Donald; Garrison, Daniel

    2009-01-01

    Eucrites and howardites, more than most meteorite types, show extensive impact resetting of their Ar-39-Ar-40 (K-Ar) ages approximately equal to 3.4-4.1 Ga ago, and many specimens show some disturbance of other radiometry chronometers as well. Bogard (1995) argued that this age resetting occurred on Vesta and was produced by the same general population of objects that produced many of the lunar impact basins. The exact nature of the lunar late heavy bombardment (LHB or 'cataclysm') remains controversial, but the timing is similar to the reset ages of eucrites. Neither the beginning nor ending time of the lunar LHB is well constrained. Comparison of Ar-Ar ages of brecciated eucrites with data for the lunar LHB can resolve both the origin of these impactors and the time period over which they were delivered to the inner solar system. This abstract reports some new Ar-Ar age data for eucrites, obtained since the authors' 1995 and 2003 papers.

  2. Moving Beyond the Androgen Receptor (AR): Targeting AR-Interacting Proteins to Treat Prostate Cancer

    PubMed Central

    Foley, Christopher; Mitsiades, Nicholas

    2016-01-01

    Medical or surgical castration serve as the backbone of systemic therapy for advanced and metastatic prostate cancer, taking advantage of the importance of androgen signaling in this disease. Unfortunately, resistance to castration emerges almost universally. Despite the development and approval of new and more potent androgen synthesis inhibitors and androgen receptor (AR) antagonists, prostate cancers continue to develop resistance to these therapeutics, while often maintaining their dependence on the AR signaling axis. This highlights the need for innovative therapeutic approaches that aim to continue disrupting AR downstream signaling, but are orthogonal to directly targeting the AR itself. In this review, we discuss the preclinical research that has been done, as well as clinical trials for prostate cancer, on inhibiting several important families of AR interacting proteins, including chaperones (such as HSP90 and FKBP52), pioneer factors (including FOXA1 and GATA-2), and AR transcriptional coregulators such as the p160 steroid receptor coactivators (SRCs) SRC-1, SRC-2, SRC-3, as well as lysine deacetylases (KDACs) and lysine acetyltransferases (KATs). Researching the effect of, and developing new therapeutic agents that target, the AR signaling axis is critical to advancing our understanding of prostate cancer biology, and to continuing to improve treatments for prostate cancer and for overcoming castration-resistance. PMID:26728473

  3. Moving Beyond the Androgen Receptor (AR): Targeting AR-Interacting Proteins to Treat Prostate Cancer.

    PubMed

    Foley, Christopher; Mitsiades, Nicholas

    2016-04-01

    Medical or surgical castration serves as the backbone of systemic therapy for advanced and metastatic prostate cancer, taking advantage of the importance of androgen signaling in this disease. Unfortunately, resistance to castration emerges almost universally. Despite the development and approval of new and more potent androgen synthesis inhibitors and androgen receptor (AR) antagonists, prostate cancers continue to develop resistance to these therapeutics, while often maintaining their dependence on the AR signaling axis. This highlights the need for innovative therapeutic approaches that aim to continue disrupting AR downstream signaling but are orthogonal to directly targeting the AR itself. In this review, we discuss the preclinical research that has been done, as well as clinical trials for prostate cancer, on inhibiting several important families of AR-interacting proteins, including chaperones (such as heat shock protein 90 (HSP90) and FKBP52), pioneer factors (including forkhead box protein A1 (FOXA1) and GATA-2), and AR transcriptional coregulators such as the p160 steroid receptor coactivators (SRCs) SRC-1, SRC-2, SRC-3, as well as lysine deacetylases (KDACs) and lysine acetyltransferases (KATs). Researching the effect of-and developing new therapeutic agents that target-the AR signaling axis is critical to advancing our understanding of prostate cancer biology, to continue to improve treatments for prostate cancer and for overcoming castration resistance.

  4. Potassium Isotopic Compositions of NIST Potassium Standards and 40Ar/39Ar Mineral Standards

    NASA Technical Reports Server (NTRS)

    Morgan, Leah; Tappa, Mike; Ellam, Rob; Mark, Darren; Higgins, John; Simon, Justin I.

    2013-01-01

    Knowledge of the isotopic ratios of standards, spikes, and reference materials is fundamental to the accuracy of many geochronological methods. For example, the 238U/235U ratio relevant to U-Pb geochronology was recently re-determined [1] and shown to differ significantly from the previously accepted value employed during age determinations. These underlying values are fundamental to accurate age calculations in many isotopic systems, and uncertainty in these values can represent a significant (and often unrecognized) portion of the uncertainty budget for determined ages. The potassium isotopic composition of mineral standards, or neutron flux monitors, is a critical, but often overlooked component in the calculation of K-Ar and 40Ar/39Ar ages. It is currently assumed that all terrestrial materials have abundances indistinguishable from that of NIST SRM 985 [2]; this is apparently a reasonable assumption at the 0.25per mille level (1s) [3]. The 40Ar/39Ar method further relies on the assumption that standards and samples (including primary and secondary standards) have indistinguishable 40K/39K values. We will present data establishing the potassium isotopic compositions of NIST isotopic K SRM 985, elemental K SRM 999b, and 40Ar/39Ar biotite mineral standard GA1550 (sample MD-2). Stable isotopic compositions (41K/39K) were measured by the peak shoulder method with high resolution MC-ICP-MS (Thermo Scientific NEPTUNE Plus), using the accepted value of NIST isotopic SRM 985 [2] for fractionation [4] corrections [5]. 40K abundances were measured by TIMS (Thermo Scientific TRITON), using 41K/39K values from ICP-MS measurements (or, for SRM 985, values from [2]) for internal fractionation corrections. Collectively these data represent an important step towards a metrologically traceable calibration of 40K concentrations in primary 40Ar/39Ar mineral standards and improve uncertainties by ca. an order of magnitude in the potassium isotopic compositions of standards.

  5. Whole-Rock 40Ar/39Ar Step-heating Analyses, Problems and Potential

    NASA Astrophysics Data System (ADS)

    Boehnke, P.; Harrison, M.; Heizler, M. T.; Lovera, O. M.; Warren, P. H.

    2015-12-01

    Whole-rock 40Ar/39Ar step-heating analyses of extra-terrestrial materials are used to constrain the impact history of the inner solar system, the formation age of the Moon, and timing of paleomagnetic fields. Despite the importance of knowing the timing of these important events, the samples we have in hand are usually disturbed through mixing, (multiple?) impact events, and perhaps recoil loss. Extra-terrestrial 40Ar/39Ar data are typically interpreted through the assignment of essentially arbitrary plateau ages rather than through a robust physical model. Although the use of models capable of quantitatively assessing diffusive 40Ar* loss in extra-terrestrial samples has been around for nearly 50 years, this early advance has been widely ignored. Here we present implications of applying a robust, multi-activation energy, multi-diffusion domain model to step-heated 40Ar/39Ar data, with temperature cycling. Our findings show that for even a single heating event, "plateau" ages are unlikely to record meaningful ages. Further, if the sample has experienced multiple heating events or contains inherited clasts, recovering a unique solution may be impossible. Indeed the most readily interpretable portion of the age spectrum is the early heating steps which represents a maximum age estimate of the last re-heating event. Our results challenge the chronologic validity of 40Ar/39Ar "plateau" ages and by extension the hypotheses that are based on this data (e.g., the Late Heavy Bombardment). Future work will require new analytical procedures, interpretative frameworks, and (potentially) the combination of multiple chronometers to derive a robust impact history for the early solar system.

  6. Experiences from the ARS croplands CEAP program

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The multi-agency Conservation Effects Assessment Project (CEAP) within USDA produced a number of lessons that should be applicable to the use of landscape approaches to place bioenergy crops. Results from the ARS Croplands Watersheds CEAP, the NRCS CEAP, and the NIFA CEAP Watershed Assessment Studie...

  7. Lignocellulosic Biofuels: Bioenergy Research at ARS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The growth and long-term viability of bioenergy production in the Nation are impeded by a number of technical and commercial barriers. Agricultural Research Service (ARS) addresses technical barriers and does so by leveraging its strengths and unique capabilities to (1) pursue technical barriers th...

  8. 78 FR 56979 - Arkansas Disaster # AR-00065

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-16

    ... From the Federal Register Online via the Government Publishing Office ] SMALL BUSINESS ADMINISTRATION Arkansas Disaster AR-00065 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for...

  9. 78 FR 9448 - Arkansas Disaster #AR-00061

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-08

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Arkansas Disaster AR-00061 AGENCY: U.S. Small Business Administration. ACTION: Notice SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for...

  10. 76 FR 42154 - Arkansas Disaster #AR-00050

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-18

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Arkansas Disaster AR-00050 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for the State of Arkansas...

  11. 76 FR 42155 - Arkansas Disaster #AR-00051

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-18

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Arkansas Disaster AR-00051 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for...

  12. 78 FR 39821 - Arkansas Disaster #AR-00064

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-02

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Arkansas Disaster AR-00064 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for...

  13. 75 FR 7637 - Arkansas Disaster #AR-00040

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-22

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Arkansas Disaster AR-00040 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of Arkansas dated...

  14. 75 FR 30872 - Arkansas Disaster # AR-00043

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-02

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Arkansas Disaster AR-00043 AGENCY: U.S. Small Business Administration. ACTION: Notice SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of Arkansas dated...

  15. 76 FR 27140 - Arkansas Disaster # AR-00049

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-10

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Arkansas Disaster AR-00049 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for...

  16. 76 FR 27139 - Arkansas Disaster #AR-00048

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-10

    ... From the Federal Register Online via the Government Publishing Office ] SMALL BUSINESS ADMINISTRATION Arkansas Disaster AR-00048 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for the State of Arkansas...

  17. High Spatial Resolution 40Ar/39Ar Geochronology of Impact Melt Breccias from Apollo 17 Boulders at Stations 2, 6, and 7

    NASA Astrophysics Data System (ADS)

    Mercer, C. M.; Hodges, K. V.; Jolliff, B. L.; Van Soest, M. C.; Wartho, J. A.; Weirich, J. R.

    2015-12-01

    Several boulders located at the bases of the North and South Massifs were among the primary field targets of the Apollo 17 mission to the Taurus-Littrow Valley on the Moon [1]. Some boulders are polylithologic, including Boulder 1 at Station 2 and the boulders at Stations 6 and 7. These boulders were the subjects of consortium studies [2, 3] that included 40Ar/39Ar geochronology to determine the ages of distinct lithologies within each boulder [e.g., 4-6]. We report new 40Ar/39Ar data for the impact melt breccias 72255, 76315, 77075, and 77135 obtained using the UV laser ablation microprobe (UVLAMP) methods of [7]. For 72255, we obtained a preliminary isochron date ca. 3814 Ma from 22 melt analyses, which is younger than published plateau dates (e.g., 3951-3835 Ma [4, 8]). Fifteen melt analyses of 76315 yield a preliminary isochron date ca. 3850 Ma, younger than the 3900 ± 16 Ma date reported by [8]. Melt analyses of 77075 yield preliminary dates between ca. 3797-3584 Ma, possibly reflecting partial loss of 40Ar. In this case, the oldest date may provide a minimum age for the formation of melt in 77075. Finally, the UVLAMP dates for the 77135 melt range from 3810-3361 Ma and corresponding Ca/K ratios range from ca. 100-6. Electron microprobe analyses of small (ca. 10s of microns wide) pockets of K-rich materials show that both K-rich glass and K-feldspar are present. The UVLAMP dates for 77135 likely reflect spatially variable 40Ar loss, consistent with published step heating results [e.g., 6]. References: [1] Schmitt (1973) Science, 182, 681-690. [2] Ryder (1993). Catalog of Apollo 17 Rocks: Volume 1 - Stations 2 and 3 (South Massif). LPI. [3] Ryder (1993). Catalog of Apollo 17 Rocks: Volume 4 - North Massif. LPI. [4] Leich et al. (1975) The Moon, 14, 407-444. [5] Cadogan & Turner (1976). LPSC, 7, 2267-2285. [6] Stettler et al. (1978). LPSC, 9, 1113-1115. [7] Mercer et al. (2015) Sci. Adv., 1, e1400050. [8] Dalrymple & Ryder (1996). JGR, 101, 26069-26084.

  18. Identification of a novel HLA-A allele, A*3120.

    PubMed

    Chang, Y; Pascual, C J; Alonzo, P; Chamizo, A

    2009-03-01

    A novel human leukocyte antigen (HLA)-A allele, HLA-A*3120, was first identified in a National Marrow Donor Program (NMDP) donor. The A*3120 allele resulted from a single nucleotide substitution (T to G) at codon 92 of exon 3 of A*310102. The substitution caused an amino acid change (serine to alanine). This novel allele was also seen in two other unrelated NMDP donors.

  19. Thinking about "Rich" Tasks

    ERIC Educational Resources Information Center

    Box, Lorna; Watson, Anne

    2010-01-01

    This article presents an e-mail conversation between two teachers discussing how to have a "rich task" lesson in which they get to the heart of mathematical modeling and in which students are motivated into working on mathematics. One teacher emphasizes that the power of maths is in developing mathematical descriptions of situations by…

  20. From Rags to Riches

    ERIC Educational Resources Information Center

    Sweet, Colleen

    2008-01-01

    In this article, the author presents the "Rags to Riches" design project she introduced to her students. She assigned each of her students one item from an array to thrift store goods which included old scarves, sweaters, jackets, and even evening gowns. The design problem was to imagine what a clothing tag might look like if the assigned item…

  1. The ChArMEx database

    NASA Astrophysics Data System (ADS)

    Ferré, Hélène; Belmahfoud, Nizar; Boichard, Jean-Luc; Brissebrat, Guillaume; Cloché, Sophie; Descloitres, Jacques; Fleury, Laurence; Focsa, Loredana; Henriot, Nicolas; Mière, Arnaud; Ramage, Karim; Vermeulen, Anne; Boulanger, Damien

    2015-04-01

    The Chemistry-Aerosol Mediterranean Experiment (ChArMEx, http://charmex.lsce.ipsl.fr/) aims at a scientific assessment of the present and future state of the atmospheric environment in the Mediterranean Basin, and of its impacts on the regional climate, air quality, and marine biogeochemistry. The project includes long term monitoring of environmental parameters , intensive field campaigns, use of satellite data and modelling studies. Therefore ChARMEx scientists produce and need to access a wide diversity of data. In this context, the objective of the database task is to organize data management, distribution system and services, such as facilitating the exchange of information and stimulating the collaboration between researchers within the ChArMEx community, and beyond. The database relies on a strong collaboration between ICARE, IPSL and OMP data centers and has been set up in the framework of the Mediterranean Integrated Studies at Regional And Locals Scales (MISTRALS) program data portal. ChArMEx data, either produced or used by the project, are documented and accessible through the database website: http://mistrals.sedoo.fr/ChArMEx. The website offers the usual but user-friendly functionalities: data catalog, user registration procedure, search tool to select and access data... The metadata (data description) are standardized, and comply with international standards (ISO 19115-19139; INSPIRE European Directive; Global Change Master Directory Thesaurus). A Digital Object Identifier (DOI) assignement procedure allows to automatically register the datasets, in order to make them easier to access, cite, reuse and verify. At present, the ChArMEx database contains about 120 datasets, including more than 80 in situ datasets (2012, 2013 and 2014 summer campaigns, background monitoring station of Ersa...), 25 model output sets (dust model intercomparison, MEDCORDEX scenarios...), a high resolution emission inventory over the Mediterranean... Many in situ datasets

  2. ARS5 is a component of the 26S proteasome complex and negatively regulates thiol biosynthesis and arsenic tolerance in Arabidopsis

    PubMed Central

    Sung, Dong-Yul; Kim, Tae-Houn; Komives, Elizabeth A.; Mendoza-Cózatl, David G.; Schroeder, Julian I.

    2010-01-01

    Summary A forward genetic screen in Arabidopsis led to the isolation of several arsenic tolerance mutants. ars5 is the strongest arsenate and arsenite resistant mutant identified in this genetic screen. Here, we report the characterization and cloning of the ars5 mutant gene. ars5 is shown to exhibit an increased accumulation of arsenic and thiol compounds during arsenic stress. Rough mapping together with microarray-based expression mapping identified the ars5 mutation in the alpha subunit F (PAF1) of the 26S proteasome complex. Characterization of an independent paf1 T-DNA insertion allele and complementation by PAF1 confirmed that paf1 mutation is responsible for the enhanced thiol accumulation and the arsenic tolerance phenotypes. Arsenic tolerance was not observed in a knockout mutant of the highly homologous PAF2 gene. However, genetic complementation of ars5 by over expression of PAF2 suggests that the PAF2 protein is functionally equivalent to PAF1 when expressed at high levels. No detectible difference was observed in total ubiquitinylated protein profiles between ars5 and wild type Arabidopsis, suggesting that the arsenic tolerance observed in ars5 is not derived from a general impairment in proteasome-mediated protein degradation. Quantitative RT-PCR showed that arsenic induces enhanced transcriptional activation of several key genes that function in glutathione and phytochelatin biosynthesis in wild type and this arsenic-induction of gene expression is more dramatic in ars5. The enhanced transcriptional response to arsenic and the increased accumulation of thiol compounds in ars5 compared to WT suggest the presence of a positive regulation pathway for thiol biosynthesis that is enhanced in the ars5 background. PMID:19453443

  3. Novel HLA-A and HLA-B alleles.

    PubMed

    Hurley, C K; Steiner, N; Kosman, C; Mitton, W; Koester, R; Bei, M; Bush, J; McCormack, J; Hahn, A; Henson, V; Hoyer, R; Wade, J A; Hartzman, R J; Ng, J

    1998-07-01

    Nine novel HLA-A and HLA-B alleles are described: A*2609, A*6803, A*6806, B*1539, B*1540, B*2712, B*4103, B*5109, and B*5603. Most appear to have arisen by gene conversion events. B*5603 appears to have arisen by a reciprocal recombination event joining exon 2 of a B*55/ *56 allele with exon 3 of a B*15 allele. Serologically, the antigen encoded by this allele types with broad B22- and Bw6-specific alloantisera. Also unique, the antigen encoded by B*2712 does not react with B27-specific alloantisera but does react with Bw6-specific alloantisera.

  4. Mutated tumor alleles are expressed according to their DNA frequency.

    PubMed

    Castle, John C; Loewer, Martin; Boegel, Sebastian; Tadmor, Arbel D; Boisguerin, Valesca; de Graaf, Jos; Paret, Claudia; Diken, Mustafa; Kreiter, Sebastian; Türeci, Özlem; Sahin, Ugur

    2014-04-22

    The transcription of tumor mutations from DNA into RNA has implications for biology, epigenetics and clinical practice. It is not clear if mutations are in general transcribed and, if so, at what proportion to the wild-type allele. Here, we examined the correlation between DNA mutation allele frequency and RNA mutation allele frequency. We sequenced the exome and transcriptome of tumor cell lines with large copy number variations, identified heterozygous single nucleotide mutations and absolute DNA copy number, and determined the corresponding DNA and RNA mutation allele fraction. We found that 99% of the DNA mutations in expressed genes are expressed as RNA. Moreover, we found a high correlation between the DNA and RNA mutation allele frequency. Exceptions are mutations that cause premature termination codons and therefore activate nonsense-mediated decay. Beyond this, we did not find evidence of any wide-scale mechanism, such as allele-specific epigenetic silencing, preferentially promoting mutated or wild-type alleles. In conclusion, our data strongly suggest that genes are equally transcribed from all alleles, mutated and wild-type, and thus transcribed in proportion to their DNA allele frequency.

  5. Anatomy of an Inversion-46Ar

    NASA Astrophysics Data System (ADS)

    Zamick, Larry; Robinson, Shadow; Sharon, Yitzhak

    2011-04-01

    Two different interactions give very close results for properties of most even-even Ar isotopes, but for 46 Ar the results diverge. The interactions in question are a). WBT and b). SPDF-U. For 42 , 44 , 46 Ar the results are as follows : WBT E(21 +) (1 . 29 , 1 . 17 , 1 . 14) MeV E(22 +) (2 . 32 , 1 . 80 , 2 . 10) MeV g(21 +) (- . 095 , - . 022 , + . 100) g(22 +) (. 096 , . 045 , - . 070) SPDF-U E(21 +) (1 . 15 , 1 . 09 , 1 . 59) MeV E(22 +) (2 . 28 , 1 . 78 , 3 . 77) MeV g(21 +) (- . 084 , - . 040 , + . 513) g(22 +) (+ . 075 , + . 346 , + . 514). To understand the big differences for A = 46 we must look to the odd K isotopes. Consider the J = 3 / 2+-- J = 1 / 2+ splitting.(MeV) EXPT/WBT/SPDF-U A = 43 0 . 561 , 1 . 109 , 0 . 672 A = 45 0 . 474 , 0 . 871 , 0 . 345 A = 47 - 0 . 360 , 0 . 507 , - 0 . 320 A = 49 0 . 200 , 0 . 729 , 0 . 078 . We see that there is an inversion in the ``d3/2 -s1/2'' splitting for 47 K. The SPDF-U interaction successfully gives this inversion but WBT does not. Things are a bit different for B(E2, 01 - 21) . The values in e2 fm4 are WBT (338 , 425 , 541) /SPDF-U (351 , 357 , 525). Here the 2 interactions give very similar results. Both interactions yield a larger B(E2) for 46Ar than for 44Ar, as do previous calculations by others. This despite the fact that in single j A = 46 has a closed shell of neutrons. Most experimental measurements had the opposite--larger B(E2) for A = 44 than for A = 46 . But a most recent measurement by Mengone et al. disagrees with all previous measurements and agrees with the current shell model calculations.

  6. Cooperative Dynamics of AR and ER Activity in Breast Cancer.

    PubMed

    D'Amato, Nicholas C; Gordon, Michael A; Babbs, Beatrice; Spoelstra, Nicole S; Carson Butterfield, Kiel T; Torkko, Kathleen C; Phan, Vernon T; Barton, Valerie N; Rogers, Thomas J; Sartorius, Carol A; Elias, Anthony; Gertz, Jason; Jacobsen, Britta M; Richer, Jennifer K

    2016-11-01

    Androgen receptor (AR) is expressed in 90% of estrogen receptor alpha-positive (ER(+)) breast tumors, but its role in tumor growth and progression remains controversial. Use of two anti-androgens that inhibit AR nuclear localization, enzalutamide and MJC13, revealed that AR is required for maximum ER genomic binding. Here, a novel global examination of AR chromatin binding found that estradiol induced AR binding at unique sites compared with dihydrotestosterone (DHT). Estradiol-induced AR-binding sites were enriched for estrogen response elements and had significant overlap with ER-binding sites. Furthermore, AR inhibition reduced baseline and estradiol-mediated proliferation in multiple ER(+)/AR(+) breast cancer cell lines, and synergized with tamoxifen and fulvestrant. In vivo, enzalutamide significantly reduced viability of tamoxifen-resistant MCF7 xenograft tumors and an ER(+)/AR(+) patient-derived model. Enzalutamide also reduced metastatic burden following cardiac injection. Finally, in a comparison of ER(+)/AR(+) primary tumors versus patient-matched local recurrences or distant metastases, AR expression was often maintained even when ER was reduced or absent. These data provide preclinical evidence that anti-androgens that inhibit AR nuclear localization affect both AR and ER, and are effective in combination with current breast cancer therapies. In addition, single-agent efficacy may be possible in tumors resistant to traditional endocrine therapy, as clinical specimens of recurrent disease demonstrate AR expression in tumors with absent or refractory ER.

  7. Metalloregulatory properties of the ArsD repressor.

    PubMed

    Chen, Y; Rosen, B P

    1997-05-30

    The plasmid-encoded arsenical resistance (ars) operon of plasmid R773 produces resistance to trivalent and pentavalent salts of the metalloids arsenic and antimony in cells of Escherichia coli. The first two genes in the operon, arsR and arsD, were previously shown to encode trans-acting repressor proteins. ArsR controls the basal level of expression of the operon, while ArsD controls maximal expression. Thus, action of the two repressors form a homeostatic regulatory circuit that maintains the level of ars expression within a narrow range. In this study, we demonstrate that ArsD binds to the same site on the ars promoter element as ArsR but with 2 orders of magnitude lower affinity. The results of gel shift assays demonstrate that ArsD is released from the ars DNA promoter by phenylarsine oxide, sodium arsenite, and potassium antimonyl tartrate (in order of effectiveness), the same inducers to which ArsR responds. Using the quenching of intrinsic tryptophan fluorescence to measure the affinity of the repressor for inducers, apparent Kd values for Sb(III) and As(III) of 2 and 60 microM, respectively, were obtained. These results demonstrate that the arsR-arsD pair provide a sensitive mechanism for sensing a wide range of environmental heavy metals.

  8. The miR9863 family regulates distinct Mla alleles in barley to attenuate NLR receptor-triggered disease resistance and cell-death signaling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Barley Mla alleles encode coiled-coil (CC), nucleotide binding and leucine-rich repeat (NB-LRR) intracellular receptors that trigger isolate-specific immune responses against the powdery mildew fungus, Blumeria graminis f. sp. hordei (Bgh). How Mla or NB-LRR genes in grass species are regulated at p...

  9. Analyses of Allele-Specific Gene Expression in Highly Divergent Mouse Crosses Identifies Pervasive Allelic Imbalance

    PubMed Central

    Crowley, James J; Zhabotynsky, Vasyl; Sun, Wei; Huang, Shunping; Pakatci, Isa Kemal; Kim, Yunjung; Wang, Jeremy R; Morgan, Andrew P; Calaway, John D; Aylor, David L; Yun, Zaining; Bell, Timothy A; Buus, Ryan J; Calaway, Mark E; Didion, John P; Gooch, Terry J; Hansen, Stephanie D; Robinson, Nashiya N; Shaw, Ginger D; Spence, Jason S; Quackenbush, Corey R; Barrick, Cordelia J; Nonneman, Randal J.; Kim, Kyungsu; Xenakis, James; Xie, Yuying; Valdar, William; Lenarcic, Alan B; Wang, Wei; Welsh, Catherine E; Fu, Chen-Ping; Zhang, Zhaojun; Holt, James; Guo, Zhishan; Threadgill, David W; Tarantino, Lisa M; Miller, Darla R; Zou, Fei; McMillan, Leonard; Sullivan, Patrick F; de Villena, Fernando Pardo-Manuel

    2015-01-01

    Complex human traits are influenced by variation in regulatory DNA through mechanisms that are not fully understood. Since regulatory elements are conserved between humans and mice, a thorough annotation of cis regulatory variants in mice could aid in this process. Here we provide a detailed portrait of mouse gene expression across multiple tissues in a three-way diallel. Greater than 80% of mouse genes have cis regulatory variation. These effects influence complex traits and usually extend to the human ortholog. Further, we estimate that at least one in every thousand SNPs creates a cis regulatory effect. We also observe two types of parent-of-origin effects, including classical imprinting and a novel, global allelic imbalance in favor of the paternal allele. We conclude that, as with humans, pervasive regulatory variation influences complex genetic traits in mice and provide a new resource toward understanding the genetic control of transcription in mammals. PMID:25730764

  10. Allele-specific deposition of macroH2A1 in Imprinting Control Regions

    SciTech Connect

    Choo, J H; Kim, J D; Chung, J H; Stubbs, L; Kim, J

    2006-01-13

    In the current study, we analyzed the deposition patterns of macroH2A1 at a number of different genomic loci located in X chromosome and autosomes. MacroH2A1 is preferentially deposited at methylated CpG CpG-rich regions located close to promoters. The macroH2A1 deposition patterns at the methylated CpG islands of several imprinted domains, including the Imprinting Control Regions (ICRs) of Xist, Peg3, H19/Igf2 Igf2, Gtl2/Dlk1, and Gnas domains, show consistent allele-specificity towards inactive, methylated alleles. The macroH2A1 deposition levels at the ICRs and other Differentially Methylated Regions (DMRs) of these domains are also either higher or comparable to those observed at the inactive X chromosome of female mammals. Overall, our results indicate that besides DNA methylation macroH2A1 is another epigenetic component in the chromatin of ICRs displaying differential association with two parental alleles.

  11. Age and origin of carlsbad cavern and related caves from 40Ar/39Ar of alunite

    PubMed

    Polyak; McIntosh; Guven; Provencio

    1998-03-20

    40Ar/39Ar dating of fine-grained alunite that formed during cave genesis provides ages of formation for the Big Room level of Carlsbad Cavern [4.0 to 3.9 million years ago (Ma)], the upper level of Lechuguilla Cave (6.0 to 5.7 Ma), and three other hypogene caves (11.3 to 6.0 Ma) in the Guadalupe Mountains of New Mexico. Alunite ages increase and are strongly correlative with cave elevations, which indicates an 1100-meter decline in the water table, apparently related to tectonic uplift and tilting, from 11.3 Ma to the present. 40Ar/39Ar dating studies of the hypogene caves have the potential to help resolve late Cenozoic climatic, speleologic, and tectonic questions.

  12. Quaternary continental weathering geochronology by laser-heating 40Ar/39Ar analysis of supergene cryptomelane

    NASA Astrophysics Data System (ADS)

    Feng, Yuexing; Vasconcelos, Paulo

    2001-07-01

    Incremental laser-heating analyses of supergene cryptomelane clusters extracted from three distinct weathering profiles from the Mary Valley region, southeast Queensland, Australia, yield reproducible and well-defined plateau ages ranging from 346 ± 15 to 291 ± 14 ka (2 σ). Precipitation of supergene cryptomelane in this period implies that relative humid climate prevailed in southeast Queensland from 340 to 290 ka, a result consistent with oxygen isotope analyses of marine sediments from Ocean Drilling Program Site 820 and with regional pollen and spore records. These results, the first report on the precise 40Ar/39Ar dating of Quaternary supergene cryptomelane, indicate that 40Ar/39Ar analysis of pedogenic minerals provides a reliable geochronometer for the study of Quaternary surficial processes useful in the study of soil formation rates, continental paleoclimates, and archaeological sites devoid of datable volcanic minerals.

  13. Multimer Formation Explains Allelic Suppression of PRDM9 Recombination Hotspots

    PubMed Central

    Baker, Christopher L.; Petkova, Pavlina; Walker, Michael; Flachs, Petr; Mihola, Ondrej; Trachtulec, Zdenek; Petkov, Petko M.; Paigen, Kenneth

    2015-01-01

    Genetic recombination during meiosis functions to increase genetic diversity, promotes elimination of deleterious alleles, and helps assure proper segregation of chromatids. Mammalian recombination events are concentrated at specialized sites, termed hotspots, whose locations are determined by PRDM9, a zinc finger DNA-binding histone methyltransferase. Prdm9 is highly polymorphic with most alleles activating their own set of hotspots. In populations exhibiting high frequencies of heterozygosity, questions remain about the influences different alleles have in heterozygous individuals where the two variant forms of PRDM9 typically do not activate equivalent populations of hotspots. We now find that, in addition to activating its own hotspots, the presence of one Prdm9 allele can modify the activity of hotspots activated by the other allele. PRDM9 function is also dosage sensitive; Prdm9 +/- heterozygous null mice have reduced numbers and less active hotspots and increased numbers of aberrant germ cells. In mice carrying two Prdm9 alleles, there is allelic competition; the stronger Prdm9 allele can partially or entirely suppress chromatin modification and recombination at hotspots of the weaker allele. In cell cultures, PRDM9 protein variants form functional heteromeric complexes which can bind hotspots sequences. When a heteromeric complex binds at a hotspot of one PRDM9 variant, the other PRDM9 variant, which would otherwise not bind, can still methylate hotspot nucleosomes. We propose that in heterozygous individuals the underlying molecular mechanism of allelic suppression results from formation of PRDM9 heteromers, where the DNA binding activity of one protein variant dominantly directs recombination initiation towards its own hotspots, effectively titrating down recombination by the other protein variant. In natural populations with many heterozygous individuals, allelic competition will influence the recombination landscape. PMID:26368021

  14. Multimer Formation Explains Allelic Suppression of PRDM9 Recombination Hotspots.

    PubMed

    Baker, Christopher L; Petkova, Pavlina; Walker, Michael; Flachs, Petr; Mihola, Ondrej; Trachtulec, Zdenek; Petkov, Petko M; Paigen, Kenneth

    2015-09-01

    Genetic recombination during meiosis functions to increase genetic diversity, promotes elimination of deleterious alleles, and helps assure proper segregation of chromatids. Mammalian recombination events are concentrated at specialized sites, termed hotspots, whose locations are determined by PRDM9, a zinc finger DNA-binding histone methyltransferase. Prdm9 is highly polymorphic with most alleles activating their own set of hotspots. In populations exhibiting high frequencies of heterozygosity, questions remain about the influences different alleles have in heterozygous individuals where the two variant forms of PRDM9 typically do not activate equivalent populations of hotspots. We now find that, in addition to activating its own hotspots, the presence of one Prdm9 allele can modify the activity of hotspots activated by the other allele. PRDM9 function is also dosage sensitive; Prdm9+/- heterozygous null mice have reduced numbers and less active hotspots and increased numbers of aberrant germ cells. In mice carrying two Prdm9 alleles, there is allelic competition; the stronger Prdm9 allele can partially or entirely suppress chromatin modification and recombination at hotspots of the weaker allele. In cell cultures, PRDM9 protein variants form functional heteromeric complexes which can bind hotspots sequences. When a heteromeric complex binds at a hotspot of one PRDM9 variant, the other PRDM9 variant, which would otherwise not bind, can still methylate hotspot nucleosomes. We propose that in heterozygous individuals the underlying molecular mechanism of allelic suppression results from formation of PRDM9 heteromers, where the DNA binding activity of one protein variant dominantly directs recombination initiation towards its own hotspots, effectively titrating down recombination by the other protein variant. In natural populations with many heterozygous individuals, allelic competition will influence the recombination landscape.

  15. 40Ar/39Ar laserprobe study of the Day Nui Con Voi Metamorphic Complex, Vietnam

    NASA Astrophysics Data System (ADS)

    Wu, C.; Lo, C.; Yeh, M.; Chung, S.; Lee, T.

    2009-12-01

    The garnet bearing gneiss within the Day Nui Con Voi (DNCV) Metamorphic Complex along the Red River Shear Zone (RRSZ) in North Vietnam, recorded a long tectonothermal history since the Indosinian orogeny. In-situ 40Ar/39Ar laserprobe study of biotite inclusions within garnet porphyroblasts and matrix biotites, combining with microstructural and scanning electron microscopy (SEM) studies, deciphered the timing and duration of thermal events. Biotites from two matrix fabrics from different deformation events show approximately similar 40Ar/39Ar age ranges in 19-24Ma, depending grain size. These matrix biotite ages are best interpreted to record a rapid cooling event associating with the left-lateral shearing event of the RRSZ. Whereas, all biotite inclusions exhibit age zoning patterns with 40Ar/39Ar ages gradually increase from 17 Ma to more than 28 Ma according to their diffusion pathways. These age variations may have resultant from a combination effect of argon retention by garnet shielding, which provides a best recorder to the metamorphic event, and argon diffusion loss along the deformed cracks during the shearing event of the RRSZ. Diffusion modeling of these age zoning indicated that the total duration of argon diffusion loss may have lasted for nearly 9 Myr and argon diffusion may have occurred sometime around 24.5Ma. These results are generally in good agreement with previous interpretation, but provide better resolution of 40Ar/39Ar age data for deciphering the history of thermal event in the DNCV Metamorphic Complex and the left-lateral shearing event of the RRSZ in Vietnam, as well.

  16. 40Ar/39Ar Geochronology by Multi-collector Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Cosca, M.

    2007-12-01

    The ushering in of a new generation of multi-collector mass spectrometers for 40Ar/39Ar geochronology represents a major technological advance, but what are the true benefits of making routine measurements with such machines versus the practical aspects of additional setup and calibration? Is argon multi-collection the way of the future? Recent experiences with a three collector Nu Instruments Noblesse mass spectrometer will be presented that address these questions. One immediate observation is that electronic stability improves average precision of the isotopic measurements. For example, on any given day 100 consecutive automated air pipette measurements yield 40Ar/36Ar ratios reproducible to 0.1%. One of the great advantages of multi-collection 40Ar/39Ar geochronology is the flexibility and ease of changing detector array configurations, which is useful when measuring irradiation packages with a range of K-content or grain size. For example, in situ UV laser ablation of micas or laser step-heating single grains of amphibole may be run by peak hopping on a single detector, while single grains of muscovite may be run by laser step-heating and analyzed by multi-collection. One of the drawbacks with multi-collection is the effort required with detector calibration and intercalibration. Source and detector discrimination and mass fractionation, however can be accomplished using air pipettes as an argon reference material. A series of experiments using sanidine standards have been performed that demonstrate the reproducibility of single collector and multi-collector measurements, with some as yet unexplained shifts using different detector arrays. Finally, several examples applying multi-collection 40Ar/39Ar data collection will be given that illustrate the utility of multi-collector measurements on a variety of mineral and rock materials.

  17. Ar-Ar Dating of Martian Meteorite, Dhofar 378: An Early Shock Event?

    NASA Technical Reports Server (NTRS)

    Park, J.; Bogard, D. D.

    2006-01-01

    Martian meteorite, Dhofar 378 (Dho378) is a basaltic shergottite from Oman, weighing 15 g, and possessing a black fusion crust. Chemical similarities between Dho378 and the Los Angeles 001 shergottite suggests that they might have derived from the same Mars locale. The plagioclase in other shergottites has been converted to maskelenite by shock, but Dho378 apparently experienced even more intense shock heating, estimated at 55-75 GPa. Dho378 feldspar (approximately 43 modal %) melted, partially flowed and vesiculated, and then partially recrystallized. Areas of feldspathic glass are appreciably enriched in K, whereas individual plagioclases show a range in the Or/An ratio of approximately 0.18-0.017. Radiometric dating of martian shergottites indicate variable formation times of 160-475 Myr, whereas cosmic ray exposure (CRE) ages of shergottites indicate most were ejected from Mars within the past few Myr. Most determined Ar-39-Ar-40 ages of shergottites appear older than other radiometric ages because of the presence of large amounts of martian atmosphere or interior Ar-40. Among all types of meteorites and returned lunar rocks, the impact event that initiated the CRE age very rarely reset the Ar-Ar age. This is because a minimum time and temperature is required to facilitate Ar diffusion loss. It is generally assumed that the shock-texture characteristics in martian meteorites were produced by the impact events that ejected the rocks from Mars, although the time of these shock events (as opposed to CRE ages) are not directly dated. Here we report Ar-39-Ar-40 dating of Dho378 plagioclase. We suggest that the determined age dates the intense shock heating event this meteorite experienced, but that it was not the impact that initiated the CRE age.

  18. Successful prediction of genetic richness at wild potato collection sites in southeastern Arizona

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Much time, money, and effort is needed to collect even a fraction of the potential geographic range of wild potato species, so there is efficiency to gain if one could predict and prioritize spots particularly rich in unique alleles for collecting. A previous experiment that used AFLP markers to com...

  19. The ChArMEx database

    NASA Astrophysics Data System (ADS)

    Ferré, Hélène; Descloitres, Jacques; Fleury, Laurence; Boichard, Jean-Luc; Brissebrat, Guillaume; Focsa, Loredana; Henriot, Nicolas; Mastrorillo, Laurence; Mière, Arnaud; Vermeulen, Anne

    2013-04-01

    The Chemistry-Aerosol Mediterranean Experiment (ChArMEx, http://charmex.lsce.ipsl.fr/) aims at a scientific assessment of the present and future state of the atmospheric environment in the Mediterranean Basin, and of its impacts on the regional climate, air quality, and marine biogeochemistry. The project includes long term monitoring of environmental parameters, intensive field campaigns, use of satellite data and modelling studies. Therefore ChARMEx scientists produce and need to access a wide diversity of data. In this context, the objective of the database task is to organize data management, distribution system and services such as facilitating the exchange of information and stimulating the collaboration between researchers within the ChArMEx community, and beyond. The database relies on a strong collaboration between OMP and ICARE data centres and falls within the scope of the Mediterranean Integrated Studies at Regional And Locals Scales (MISTRALS) program data portal. All the data produced by or of interest for the ChArMEx community will be documented in the data catalogue and accessible through the database website: http://mistrals.sedoo.fr/ChArMEx. The database website offers different tools: - A registration procedure which enables any scientist to accept the data policy and apply for a user database account. - Forms to document observations or products that will be provided to the database in compliance with metadata international standards (ISO 19115-19139; INSPIRE; Global Change Master Directory Thesaurus). - A search tool to browse the catalogue using thematic, geographic and/or temporal criteria. - Sorted lists of the datasets by thematic keywords, by measured parameters, by instruments or by platform type. - A shopping-cart web interface to order in situ data files. At present datasets from the background monitoring station of Ersa, Cape Corsica and from the 2012 ChArMEx pre-campaign are available. - A user-friendly access to satellite products

  20. Ar-40-Ar-39 microanalysis of single 74220 glass balls and 72435 breccia clasts

    NASA Technical Reports Server (NTRS)

    Huneke, J. C.

    1978-01-01

    Ar-40-Ar-39 age measurements on single orange glass balls from the Apollo 17 soil 74220 and individual clasts from the Apollo 17 highland breccia 72435 are reported. The measurements required the use of newly established microanalytical techniques to obtain high quality analyses on about 0.5 mg particles with only a few hundred ppm K. An age of 3.60 plus or minus 0.04 b.y. is determined for the orange glass. No corrections for a trapped Ar-40 component were required. The glass forming event occurred at the very end of or after the extrusion of the mare basalts at the Apollo 17 site. An extremely well defined age plateau at 3.86 plus or minus 0.04 b.y. was determined for a 72435 plagioclase clast with attached matrix. A second large plagioclase crystal yielded significantly older ages over the last 60% of Ar release at high temperatures and is a relict clast incompletely degassed at the time of breccia formation. 72435 also contains plagioclase clasts with primitive Sr and a 4.55 AE old dunite clast. The Ar results provide additional evidence for the association of chemically unequilibrated, relict clasts with both primitive Sr and older K/Ar ages.

  1. The CBM RICH project

    NASA Astrophysics Data System (ADS)

    Adamczewski-Musch, J.; Akishin, P.; Becker, K.-H.; Belogurov, S.; Bendarouach, J.; Boldyreva, N.; Chernogorov, A.; Deveaux, C.; Dobyrn, V.; Dürr, M.; Eschke, J.; Förtsch, J.; Heep, J.; Höhne, C.; Kampert, K.-H.; Kochenda, L.; Kopfer, J.; Kravtsov, P.; Kres, I.; Lebedev, S.; Lebedeva, E.; Leonova, E.; Linev, S.; Mahmoud, T.; Michel, J.; Miftakhov, N.; Niebur, W.; Ovcharenko, E.; Patel, V.; Pauly, C.; Pfeifer, D.; Querchfeld, S.; Rautenberg, J.; Reinecke, S.; Riabov, Y.; Roshchin, E.; Samsonov, V.; Tarasenkova, O.; Traxler, M.; Ugur, C.; Vznuzdaev, E.; Vznuzdaev, M.

    2017-02-01

    The CBM RICH detector is an integral component of the future CBM experiment at FAIR, providing efficient electron identification and pion suppression necessary for the measurement of rare dileptonic probes in heavy ion collisions. The RICH design is based on CO2 gas as radiator, a segmented spherical glass focussing mirror with Al+MgF2 reflective coating, and Multianode Photomultipliers for efficient Cherenkov photon detection. Hamamatsu H12700 MAPMTs have recently been selected as photon sensors, following an extensive sensor evaluation, including irradiation tests to ensure sufficient radiation hardness of the MAPMTs. A brief overview of the detector design and concept is given, results on the radiation hardness of the photon sensors are shown, and the development of a FPGA-TDC based readout chain is discussed.

  2. Application of the 40Ar/39Ar technique to date the Minoan Tuff, Santorini

    NASA Astrophysics Data System (ADS)

    Wijbrans, J. R.; Kuiper, K.; Morgan, L. E.; Klaver, M.; Vroon, P. Z.

    2012-12-01

    The age of the catastrophic eruption of the volcano of Santorini during the Bronze Age is well established from 14C dating at 3344.9 ± 7.5 a1 (uncertainties quoted as 1-σ). Application of the 40Ar/39Ar technique to products from this eruption is used here to (1) investigate the limits of the technique using conventional single collector mass spectrometry on a MAP215-50 instrument, (2) analyse sources of uncertainty to identify major contributing factors for the uncertainty of young 40Ar/39Ar ages, and (3) provide 40Ar/39Ar ages for a sample that has been previously dated via 14C and dendrochronology to further investigate issues with the accuracy of 40Ar/39Ar dating in the late Quaternary. We have separated the plagioclase fraction from the lower Minoan Tuff that immediately overlies the Cape Riva (rp6) tuff in a bay on the west coast of Thira, NW of the town of Oia. Using the calibration of 40Ar/36Ar of Lee et al.2, the decay constant recommended by Min at al.3, and the FCs age of Kuiper et al.4, we calculate an inverse isochron age of 3.7 ± 1.6 ka and a trapped 40Ar/36Ar intercept of 299.8 ± 1.2, slightly higher than the ratio for atmospheric argon of 298.56 ± 0.31, when all steps with ages > 50 ka are included in the regression. Enrichment in radiogenic 40Ar in the steps used for the isochron is extremely low, given the low concentration of K2O in plagioclase and the extremely young age. The stepwise heating approach proved useful because in all 5 replicate experiments unexpectedly high ages showed up at higher step temperatures, suggesting that in each separate some older contaminant was present. The plateaus of each of the replicate experiments had quite reproducible ages, however, and a pooled age was calculated for 23 out of 48 individual steps. The pooled age for the plateau was 17.6 ± 4.1 ka, which is high due to the slight component of excess 40Ar in the non-radiogenic component, as revealed from regression analysis. refs: 1SW Manning et al. (2006

  3. Allelic diversity in an NLR gene BPH9 enables rice to combat planthopper variation

    PubMed Central

    Zhao, Yan; Huang, Jin; Wang, Zhizheng; Jing, Shengli; Wang, Yang; Ouyang, Yidan; Cai, Baodong; Xin, Xiu-Fang; Liu, Xin; Zhang, Chunxiao; Pan, Yufang; Ma, Rui; Li, Qiaofeng; Jiang, Weihua; Zeng, Ya; Shangguan, Xinxin; Wang, Huiying; Du, Bo; Zhu, Lili; Xu, Xun; Feng, Yu-Qi; He, Sheng Yang; Chen, Rongzhi; Zhang, Qifa; He, Guangcun

    2016-01-01

    Brown planthopper (BPH), Nilaparvata lugens Stål, is one of the most devastating insect pests of rice (Oryza sativa L.). Currently, 30 BPH-resistance genes have been genetically defined, most of which are clustered on specific chromosome regions. Here, we describe molecular cloning and characterization of a BPH-resistance gene, BPH9, mapped on the long arm of rice chromosome 12 (12L). BPH9 encodes a rare type of nucleotide-binding and leucine-rich repeat (NLR)-containing protein that localizes to the endomembrane system and causes a cell death phenotype. BPH9 activates salicylic acid- and jasmonic acid-signaling pathways in rice plants and confers both antixenosis and antibiosis to BPH. We further demonstrated that the eight BPH-resistance genes that are clustered on chromosome 12L, including the widely used BPH1, are allelic with each other. To honor the priority in the literature, we thus designated this locus as BPH1/9. These eight genes can be classified into four allelotypes, BPH1/9-1, -2, -7, and -9. These allelotypes confer varying levels of resistance to different biotypes of BPH. The coding region of BPH1/9 shows a high level of diversity in rice germplasm. Homologous fragments of the nucleotide-binding (NB) and leucine-rich repeat (LRR) domains exist, which might have served as a repository for generating allele diversity. Our findings reveal a rice plant strategy for modifying the genetic information to gain the upper hand in the struggle against insect herbivores. Further exploration of natural allelic variation and artificial shuffling within this gene may allow breeding to be tailored to control emerging biotypes of BPH. PMID:27791169

  4. Observations Suggesting Allelism of the Achondroplasia and Hypochondroplasia Genes

    PubMed Central

    McKusick, Victor A.; Kelly, Thaddeus E.; Dorst, John P.

    1973-01-01

    It is argued that there are at least two alleles at the achondroplasia locus: one responsible for classic achondroplasia and one responsible for hypochondroplasia. Homozygosity for the achondroplasia gene produces a lethal skeletal dysplasia; homozygosity for hypochondroplasia has not been described. We report here a child considered to be a genetic compound for the achondroplasia and hypochondroplasia alleles. Images PMID:4697848

  5. An improved assay for the determination of Huntington`s disease allele size

    SciTech Connect

    Reeves, C.; Klinger, K.; Miller, G.

    1994-09-01

    The hallmark of Huntington`s disease (HD) is the expansion of a polymorphic (CAG)n repeat. Several methods have been published describing PCR amplification of this region. Most of these assays require a complex PCR reaction mixture to amplify this GC-rich region. A consistent problem with trinucleotide repeat PCR amplification is the presence of a number of {open_quotes}stutter bands{close_quotes} which may be caused by primer or amplicon slippage during amplification or insufficient polymerase processivity. Most assays for HD arbitrarily select a particular band for diagnostic purposes. Without a clear choice for band selection such an arbitrary selection may result in inconsistent intra- or inter-laboratory findings. We present an improved protocol for the amplification of the HD trinucleotide repeat region. This method simplifies the PCR reaction buffer and results in a set of easily identifiable bands from which to determine allele size. HD alleles were identified by selecting bands of clearly greater signal intensity. Stutter banding was much reduced thus permitting easy identification of the most relevant PCR product. A second set of primers internal to the CCG polymorphism was used in selected samples to confirm allele size. The mechanism of action of N,N,N trimethylglycine in the PCR reaction is not clear. It may be possible that the minimal isostabilizing effect of N,N,N trimethylglycine at 2.5 M is significant enough to affect primer specificity. The use of N,N,N trimethylglycine in the PCR reaction facilitated identification of HD alleles and may be appropriate for use in other assays of this type.

  6. Versatile dual-technology system for markerless allele replacement in Burkholderia pseudomallei.

    PubMed

    López, Carolina M; Rholl, Drew A; Trunck, Lily A; Schweizer, Herbert P

    2009-10-01

    Burkholderia pseudomallei is the etiologic agent of melioidosis, a rare but serious tropical disease. In the United States, genetic research with this select agent bacterium is strictly regulated. Although several select agent compliant methods have been developed for allelic replacement, all of them suffer from some drawbacks, such as a need for specific host backgrounds or use of minimal media. Here we describe a versatile select agent compliant allele replacement system for B. pseudomallei based on a mobilizable vector, pEXKm5, which contains (i) a multiple cloning site within a lacZalpha gene for facile cloning of recombinant DNA fragments, (ii) a constitutively expressed gusA indicator gene for visual detection of merodiploid formation and resolution, and (iii) elements required for resolution of merodiploids using either I-SceI homing endonuclease-stimulated recombination or sacB-based counterselection. The homing endonuclease-based allele replacement system is completed by pBADSce, which contains an araC-P(BAD)-I-sceI expression cassette for arabinose-inducible I-SceI expression and a temperature-sensitive pRO1600 replicon for facile plasmid curing. Complementing these systems is the improved Deltaasd Escherichia coli mobilizer strain RHO3. This strain is susceptible to commonly used antibiotics and allows nutritional counterselection on rich media because of its diaminopimelic acid auxotrophy. The versatility of the I-SceI- and sacB-based methods afforded by pEXKm5 in conjunction with E. coli RHO3 was demonstrated by isolation of diverse deletion mutants in several clinical, environmental, and laboratory B. pseudomallei strains. Finally, sacB-based counterselection was employed to isolate a defined chromosomal fabD(Ts) allele that causes synthesis of a temperature-sensitive FabD, an essential fatty acid biosynthesis enzyme.

  7. Assortative mating can impede or facilitate fixation of underdominant alleles.

    PubMed

    Newberry, Mitchell G; McCandlish, David M; Plotkin, Joshua B

    2016-12-01

    Underdominant mutations have fixed between divergent species, yet classical models suggest that rare underdominant alleles are purged quickly except in small or subdivided populations. We predict that underdominant alleles that also influence mate choice, such as those affecting coloration patterns visible to mates and predators alike, can fix more readily. We analyze a mechanistic model of positive assortative mating in which individuals have n chances to sample compatible mates. This one-parameter model naturally spans random mating (n=1) and complete assortment (n→∞), yet it produces sexual selection whose strength depends non-monotonically on n. This sexual selection interacts with viability selection to either inhibit or facilitate fixation. As mating opportunities increase, underdominant alleles fix as frequently as neutral mutations, even though sexual selection and underdominance independently each suppress rare alleles. This mechanism allows underdominant alleles to fix in large populations and illustrates how life history can affect evolutionary change.

  8. Estimating Relatedness in the Presence of Null Alleles.

    PubMed

    Huang, Kang; Ritland, Kermit; Dunn, Derek W; Qi, Xiaoguang; Guo, Songtao; Li, Baoguo

    2016-01-01

    Studies of genetics and ecology often require estimates of relatedness coefficients based on genetic marker data. However, with the presence of null alleles, an observed genotype can represent one of several possible true genotypes. This results in biased estimates of relatedness. As the numbers of marker loci are often limited, loci with null alleles cannot be abandoned without substantial loss of statistical power. Here, we show how loci with null alleles can be incorporated into six estimators of relatedness (two novel). We evaluate the performance of various estimators before and after correction for null alleles. If the frequency of a null allele is <0.1, some estimators can be used directly without adjustment; if it is >0.5, the potency of estimation is too low and such a locus should be excluded. We make available a software package entitled PolyRelatedness v1.6, which enables researchers to optimize these estimators to best fit a particular data set.

  9. A gene feature enumeration approach for describing HLA allele polymorphism.

    PubMed

    Mack, Steven J

    2015-12-01

    HLA genotyping via next generation sequencing (NGS) poses challenges for the use of HLA allele names to analyze and discuss sequence polymorphism. NGS will identify many new synonymous and non-coding HLA sequence variants. Allele names identify the types of nucleotide polymorphism that define an allele (non-synonymous, synonymous and non-coding changes), but do not describe how polymorphism is distributed among the individual features (the flanking untranslated regions, exons and introns) of a gene. Further, HLA alleles cannot be named in the absence of antigen-recognition domain (ARD) encoding exons. Here, a system for describing HLA polymorphism in terms of HLA gene features (GFs) is proposed. This system enumerates the unique nucleotide sequences for each GF in an HLA gene, and records these in a GF enumeration notation that allows both more granular dissection of allele-level HLA polymorphism and the discussion and analysis of GFs in the absence of ARD-encoding exon sequences.

  10. Alpha gas state in 36Ar

    NASA Astrophysics Data System (ADS)

    Akimune, Hidetoshi; Gibelin, Julien; Harakeh, Muhsin; Itoh, Masatoshi; Kawabata, Takahiro; Tamii, Atsushi; Fujiwara, Mamoru; Miki, Kenjiro; Iwamoto, Chiro; Otsu, Hideaki; Oha, Shinsuke; Tanihata, Isao; Muramoto, Tomoyuki; Kadono, Chika; Kalantar, Nasser; Ando, Shun; Leblond, Sylvian; Ayyad, Yassid; Furuno, Tatsuya; Tsynyra, Miho; Baba, Tasuo; Adachi, Satoshi; Freer, Martin

    2014-09-01

    The α cluster structures in light nuclei with N = Z are expected to appear abov the threshold energy of breakup into α particles. After the proposal of an α cluster wave function with α particle condensate type, such condensate states are both theoretically and experimentally discussed extensively. Theoretically, the existence of dilute α cluster state in nuclei with mass region of A > 16, experimentally, is not confirmed for N- α cluster states in nuclei heavier than A = 16. Recently, we measured α inelastic scattering of 36Ar followed by α decay in an inverse kinematics setup. A 50 MeV/u 36Ar beam from RCNP ring cyclotron was used to bombard a 4He gas target. α particles were detected in the magnetic spectrometer LAS which was set at 0 degrees. The α cluster structures in light nuclei with N = Z are expected to appear abov the threshold energy of breakup into α particles. After the proposal of an α cluster wave function with α particle condensate type, such condensate states are both theoretically and experimentally discussed extensively. Theoretically, the existence of dilute α cluster state in nuclei with mass region of A > 16, experimentally, is not confirmed for N- α cluster states in nuclei heavier than A = 16. Recently, we measured α inelastic scattering of 36Ar followed by α decay in an inverse kinematics setup. A 50 MeV/u 36Ar beam from RCNP ring cyclotron was used to bombard a 4He gas target. α particles were detected in the magnetic spectrometer LAS which was set at 0 degrees. Taro Hirao Grant-in-Aid for Scientific Research.

  11. 40Ar* loss in experimentally deformed muscovite and biotite with implications for 40Ar/39Ar geochronology of naturally deformed rocks

    USGS Publications Warehouse

    Cosca, M.; Stunitz, H.; Bourgeix, A.-L.; Lee, J.P.

    2011-01-01

    The effects of deformation on radiogenic argon (40Ar*) retentivity in mica are described from high pressure experiments performed on rock samples of peraluminous granite containing euhedral muscovite and biotite. Cylindrical cores, ???15mm in length and 6.25mm in diameter, were drilled from granite collected from the South Armorican Massif in northwestern France, loaded into gold capsules, and weld-sealed in the presence of excess water. The samples were deformed at a pressure of 10kb and a temperature of 600??C over a period 29 of hours within a solid medium assembly in a Griggs-type triaxial hydraulic deformation apparatus. Overall shortening in the experiments was approximately 10%. Transmitted light and secondary and backscattered electron imaging of the deformed granite samples reveals evidence of induced defects and for significant physical grain size reduction by kinking, cracking, and grain segmentation of the micas.Infrared (IR) laser (CO2) heating of individual 1.5-2.5mm diameter grains of muscovite and biotite separated from the undeformed granite yield well-defined 40Ar/39Ar plateau ages of 311??2Ma (2??). Identical experiments on single grains separated from the experimentally deformed granite yield results indicating 40Ar* loss of 0-35% in muscovite and 2-3% 40Ar* loss in biotite. Intragrain in situ ultraviolet (UV) laser ablation 40Ar/39Ar ages (??4-10%, 1??) of deformed muscovites range from 309??13 to 264??7Ma, consistent with 0-16% 40Ar* loss relative to the undeformed muscovite. The in situ UV laser ablation 40Ar/39Ar ages of deformed biotite vary from 301 to 217Ma, consistent with up to 32% 40Ar* loss. No spatial correlation is observed between in situ 40Ar/39Ar age and position within individual grains. Using available argon diffusion data for muscovite the observed 40Ar* loss in the experimentally treated muscovite can be utilized to predict average 40Ar* diffusion dimensions. Maximum 40Ar/39Ar ages obtained by UV laser ablation overlap those

  12. Mechanistic Modeling of Genetic Circuits for ArsR Arsenic Regulation.

    PubMed

    Berset, Yves; Merulla, Davide; Joublin, Aurélie; Hatzimanikatis, Vassily; van der Meer, Jan R

    2017-02-24

    Bioreporters are living cells that generate an easily measurable signal in the presence of a chemical compound. They acquire their functionality from synthetic gene circuits, the configuration of which defines the response signal and signal-to-noise ratio. Bioreporters based on the Escherichia coli ArsR system have raised significant interest for quantifying arsenic pollution, but they need to be carefully optimized to accurately work in the required low concentration range (1-10 μg arsenite L(-1)). To better understand the general functioning of ArsR-based genetic circuits, we developed a comprehensive mechanistic model that was empirically tested and validated in E. coli carrying different circuit configurations. The model accounts for the different elements in the circuits (proteins, DNA, chemical species), and their detailed affinities and interactions, and predicts the (fluorescent) output from the bioreporter cell as a function of arsenite concentration. The model was parametrized using existing ArsR biochemical data, and then complemented by parameter estimations from the accompanying experimental data using a scatter search algorithm. Model predictions and experimental data were largely coherent for feedback and uncoupled circuit configurations, different ArsR alleles, promoter strengths, and presence or absence of arsenic efflux in the bioreporters. Interestingly, the model predicted a particular useful circuit variant having steeper response at low arsenite concentrations, which was experimentally confirmed and may be useful as arsenic bioreporter in the field. From the extensive validation we expect the mechanistic model to further be a useful framework for detailed modeling of other synthetic circuits.

  13. Frequency of FCGR3B Alleles in Thai Blood Donors

    PubMed Central

    Kaset, Chollanot; Leetrakool, Nipapan; Intharanut, Kamphon

    2013-01-01

    Background Human neutrophil antigens (HNAs) are involved in autoimmune and alloimmune neutropenia and transfusion-related acute lung injury. The HNA-1 system is important in immunogenetics, and allele frequencies have been described in different populations. This study investigated the frequency of FCGR3B alleles encoding HNA-1a, HNA-1b, and HNA-1c among Thai blood donors and compared these frequencies with those previously reported for other populations. Methods Eight hundred DNA samples obtained from unrelated healthy blood donors at the National Blood Centre, Thai Red Cross Society, Bangkok, and the Blood Bank, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand, were included. Samples were simultaneously typed for each FCGR3B allele using an in-house polymerase chain reaction with sequence-specific primer (PCR-SSP) technique. Results The frequencies of FCGR3B*1, FCGR3B*2, and FCGR3B*3 alleles in central Thai blood donors were 0.548, 0.452, and 0.004, respectively; only FCGR3B*1 and FCGR3B*2 alleles were found in northern Thai blood donors (0.68 and 0.32, respectively). Compared with other Asian populations, central Thais had higher frequencies of the FCGR3B*2 allele (P<0.001), while the frequencies of the FCGR3B*1 and FCGR3B*2 alleles in northern Thais were similar to those previously reported in Taiwanese and Japanese populations. In contrast, the frequencies of the FCGR3B*1 and FCGR3B*2 alleles in the northern Thai population were statistically different from those observed in central Thai, Korean, German, and Turkish populations. Conclusions FCGR3B allele frequencies were significantly different between central and northern Thai blood donors. Our in-house PCR-SSP method is a simple, cost-effective, and convenient method for FCGR3B allele detection. PMID:24205492

  14. Microsatellite null alleles and estimation of population differentiation.

    PubMed

    Chapuis, Marie-Pierre; Estoup, Arnaud

    2007-03-01

    Microsatellite null alleles are commonly encountered in population genetics studies, yet little is known about their impact on the estimation of population differentiation. Computer simulations based on the coalescent were used to investigate the evolutionary dynamics of null alleles, their impact on F(ST) and genetic distances, and the efficiency of estimators of null allele frequency. Further, we explored how the existing method for correcting genotype data for null alleles performed in estimating F(ST) and genetic distances, and we compared this method with a new method proposed here (for F(ST) only). Null alleles were likely to be encountered in populations with a large effective size, with an unusually high mutation rate in the flanking regions, and that have diverged from the population from which the cloned allele state was drawn and the primers designed. When populations were significantly differentiated, F(ST) and genetic distances were overestimated in the presence of null alleles. Frequency of null alleles was estimated precisely with the algorithm presented in Dempster et al. (1977). The conventional method for correcting genotype data for null alleles did not provide an accurate estimate of F(ST) and genetic distances. However, the use of the genetic distance of Cavalli-Sforza and Edwards (1967) corrected by the conventional method gave better estimates than those obtained without correction. F(ST) estimation from corrected genotype frequencies performed well when restricted to visible allele sizes. Both the proposed method and the traditional correction method have been implemented in a program that is available free of charge at http://www.montpellier.inra.fr/URLB/. We used 2 published microsatellite data sets based on original and redesigned pairs of primers to empirically confirm our simulation results.

  15. Precise K-Ar, 40Ar/39Ar, Rb-Sr and U/Pb mineral ages from the 27.5 Ma fish canyon tuff reference standard

    USGS Publications Warehouse

    Lanphere, M.A.; Baadsgaard, H.

    2001-01-01

    The accuracy of ages measured using the 40Ar/39Ar technique is affected by uncertainties in the age of radiation fluence-monitor minerals. At present, there is lack of agreement about the ages of certain minerals used as fluence monitors. The accuracy of the age of a standard may be improved if the age can be measured using different decay schemes. This has been done by measuring ages on minerals from the Oligocene Fish Canyon Tuff (FCT) using the K-Ar, 40Ar/39Ar. Rb-Sr and U/Pb methods. K-Ar and 40Ar/39Ar total fusion ages of sanidine, biotite and hornblende yielded a mean age of 27.57 ?? 0.36 Ma. The weighted mean 40Ar/39Ar plateau age of sanidine and biotite is 27.57 ?? 0.18 Ma. A biotite-feldspar Rb-Sr isochron yielded an age of 27.44 ?? 0.16 Ma. The U-Pb data for zircon are complex because of the presence of Precambrian zircons and inheritance of radiogenic Pb. Zircons with 207Pb/235U < 0.4 yielded a discordia line with a lower concordia intercept of 27.52 ?? 0.09 Ma. Evaluation of the combined data suggests that the best age for FCT is 27.51 Ma. Published by Elsevier Science B.V.

  16. Deciphering post-Deccan weathering and erosion history of South Indian Archean rocks from cryptomelane 40Ar-39Ar dating

    NASA Astrophysics Data System (ADS)

    Bonnet, Nicolas; Arnaud, Nicolas; Beauvais, Anicet; Chardon, Dominique

    2015-04-01

    Since the extrusion of Deccan traps ~ 63 Ma ago, weathering and erosion processes have shaped the landscapes of this Peninsula India. This resulted in pervasive bauxitic weathering on traps and deep lateritic weathering of their basement on either side of the Western Ghats Escarpment, which separates a coastal lowland from an East-dipping highland plateau. Mn-rich lateritic profiles formed by supergene weathering of Late Archean manganiferous protores in the different greenstone belts are exposed on relict paleosurfaces, which are preserved at different elevations on the highland plateau and in the coastal lowland, allowing for direct comparison of paleosurfaces and geomorphological processes across one of the most prominent relief in the Indian peninsula. Detailed petrological and geochemical investigations of samples collected in the different Mn-rich lateritic profiles allowed for precise characterization of cryptomelane [Kx Mn8-xIV MnxIII O16, nH2O], a Mn-oxide suitable for 40Ar-39Ar dating. The ages obtained document major weathering periods at ~ 53-50 Ma, ~ 40-32 Ma, and ~ 30-23 Ma in the highland profiles, and ~ 47-45 Ma, ~ 24-19 Ma and a younger age at ~ 9 Ma in the coastal lowland profiles. The age clusters are in good agreement with major regional and global Cenozoic paleoclimatic events, e.g., the Eocene climatic optimum and the early beginnings of Asian monsoons at ~ 40 Ma. The old ages obtained both in the coastal lowland and high plateau indicate synchronous lateritic (mostly bauxitic) weathering on both sides of the escarpment. The ages also indicate that most of the incision and dissection of plateau landsurfaces must have taken place during successive periods after 45, 32 and 23 Ma, while the coastal lowland surface was only weakly incised after 19 Ma. Our results thus document post-Eocene divergent erosion and weathering histories across the escarpment since it was formed at least 47 Ma ago, suggesting installation of a dual climatic regime on

  17. Regulation of AR Degradation and Function by Ubiquitylation

    DTIC Science & Technology

    2014-10-01

    Identify ubiquitylation sites associated with degradation of the unliganded AR. We have used liquid chromatography followed by tandem mass spectrometry (LC...antagonists. Our approach has been to use initially mass spectrometry and identify AR sites that undergo ubiquitylation in the presence and absence of...Figure 1. Identification of the ubiquitylation sites of AR using mass spectrometry (LC-MS/MS). AR from VCaP cells cultured in steroid-depleted

  18. Natural selenium-rich feeds manage selenium deficiency in Oregon sheep

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A natural selenium-rich feed product (SePR) was developed by the USDA, ARS, U.S. Sheep Experiment Station for the purposes of enhancing the long-term selenium status of grazing livestock. In cooperation with Intermountain Farmers Association (Salt Lake City, UT), a bulk amount of SePR was manufactur...

  19. Assessing Ar transport paths and mechanisms in the McClure Mountains hornblende

    NASA Astrophysics Data System (ADS)

    Villa, I. M.; Grobéty, B.; Kelley, S. P.; Trigila, R.; Wieler, R.

    1996-12-01

    We have investigated the mechanisms and pathways by which Ar diffuses through the McClure Mountains hornblende (ferroan pargasite), selected as a good example of material normally dated during Ar-Ar studies. A coarse-grained hornblende separated from the same hand specimen as the MMhb-1 age standard was subjected to a hydrothermal cold-seal bomb experiment and characterized by TEM. Heated and unheated crystals were subjected to four different 39Ar/40Ar dating extraction techniques: conventional stepwise heating, infra-red laser spot, ultra-violet laser depth profiling, and closed-system stepwise etching. The stepwise heating age spectrum reproduces the features often interpreted as resulting from a concentric diffusive zonation, but the other three techniques yield results that are not compatible with such a simple picture. The IR laser data indicate that the dependence of laboratory Ar loss on grain size, predicted by Fickian diffusion, is at best poor and instead is related mainly to mineralogical variations. The depth profiles show the importance of planar zones (spaced between <1 and >150 μm from TEM evidence) in providing fast pathways for inward diffusion of atmospheric Ar from the capsule, but showed no evidence of diffusive profiles in the bulk of the hornblende lattice. The data from closed system stepwise etching underscore the role of zones rich in planar defects both for Ar loss and for nucleation of etching. The age spectra obtained by stepwise heating suffer from the differential breakdown of impurity phases, whose presence can be diagnosed with several isotope correlation plots; particularly revealing are Cl-Ca-K trends. In addition to the problems of mineral decomposition during in-vacuo laboratory degassing, an equally important decomposition occurs during many hydrothermal experiments which, combined with problems of mineral purity, have led to an overestimation of the rate of argon diffusion in hornblende. The response of hornblende to thermal

  20. Combined experimental and modeling studies of microwave activated CH4/H2/Ar plasmas for microcrystalline, nanocrystalline, and ultrananocrystalline diamond deposition

    NASA Astrophysics Data System (ADS)

    Richley, James C.; Fox, Oliver J. L.; Ashfold, Michael N. R.; Mankelevich, Yuri A.

    2011-03-01

    A comprehensive study of microwave (MW) activated CH4/H2/Ar plasmas used for diamond chemical vapor deposition is reported, focusing particularly on the effects of gross variations in the H2/Ar ratio in the input gas mixture (from H2/Ar mole fraction ratios of > 10:1, through to ˜1:99). Absolute column densities of C2(a) and CH(X) radicals and of H(n = 2) atoms have been determined by cavity ringdown spectroscopy, as functions of height (z) above a substrate and of process conditions (CH4, H2, and Ar input mole fractions, total pressure, p, and input microwave power, P). Optical emission spectroscopy has also been used to explore the relative densities of electronically excited H atoms, and CH, C2, and C3 radicals, as functions of these same process conditions. These experimental data are complemented by extensive 2D (r, z) modeling of the plasma chemistry, which provides a quantitative rationale for all of the experimental observations. Progressive replacement of H2 by Ar (at constant p and P) leads to an expanded plasma volume. Under H2-rich conditions, > 90% of the input MW power is absorbed through rovibrational excitation of H2. Reducing the H2 content (as in an Ar-rich plasma) leads to a reduction in the absorbed power density; the plasma necessarily expands in order to accommodate a given input power. The average power density in an Ar-rich plasma is much lower than that in an H2-rich plasma operating at the same p and P. Progressive replacement of H2 by Ar is shown also to result in an increased electron temperature, an increased [H]/[H2] number density ratio, but little change in the maximum gas temperature in the plasma core (which is consistently ˜3000 K). Given the increased [H]/[H2] ratio, the fast H-shifting (CyHx + H ↔ CyHx-1 + H2; y = 1-3) reactions ensure that the core of Ar-rich plasma contains much higher relative abundances of "product" species like C atoms, and C2, and C3 radicals. The effects of Ar dilution on the absorbed power

  1. Allele-Specific Reduction of the Mutant Huntingtin Allele Using Transcription Activator-Like Effectors in Human Huntington's Disease Fibroblasts.

    PubMed

    Fink, Kyle D; Deng, Peter; Gutierrez, Josh; Anderson, Joseph S; Torrest, Audrey; Komarla, Anvita; Kalomoiris, Stefanos; Cary, Whitney; Anderson, Johnathon D; Gruenloh, William; Duffy, Alexandra; Tempkin, Teresa; Annett, Geralyn; Wheelock, Vicki; Segal, David J; Nolta, Jan A

    2016-01-01

    Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by an abnormal expansion of CAG repeats. Although pathogenesis has been attributed to this polyglutamine expansion, the underlying mechanisms through which the huntingtin protein functions have yet to be elucidated. It has been suggested that postnatal reduction of mutant huntingtin through protein interference or conditional gene knockout could prove to be an effective therapy for patients suffering from HD. For allele-specific targeting, transcription activator-like effectors (TALE) were designed to target single-nucleotide polymorphisms (SNP) in the mutant allele and packaged into a vector backbone containing KRAB to promote transcriptional repression of the disease-associated allele. Additional TALEs were packaged into a vector backbone containing heterodimeric FokI and were designed to be used as nucleases (TALEN) to cause a CAG-collapse in the mutant allele. Human HD fibroblasts were treated with each TALE-SNP or TALEN. Allele-expression was measured using a SNP-genotyping assay and mutant protein aggregation was quantified with Western blots for anti-ubiquitin. The TALE-SNP and TALEN significantly reduced mutant allele expression (p < 0.05) when compared to control transfections while not affecting expression of the nondisease allele. This study demonstrates the potential of allele-specific gene modification using TALE proteins, and provides a foundation for targeted treatment for individuals suffering from Huntington's or other genetically linked diseases.

  2. Allele-specific H3K79 Di- versus trimethylation distinguishes opposite parental alleles at imprinted regions.

    PubMed

    Singh, Purnima; Han, Li; Rivas, Guillermo E; Lee, Dong-Hoon; Nicholson, Thomas B; Larson, Garrett P; Chen, Taiping; Szabó, Piroska E

    2010-06-01

    Imprinted gene expression corresponds to parental allele-specific DNA CpG methylation and chromatin composition. Histone tail covalent modifications have been extensively studied, but it is not known whether modifications in the histone globular domains can also discriminate between the parental alleles. Using multiplex chromatin immunoprecipitation-single nucleotide primer extension (ChIP-SNuPE) assays, we measured the allele-specific enrichment of H3K79 methylation and H4K91 acetylation along the H19/Igf2 imprinted domain. Whereas H3K79me1, H3K79me2, and H4K91ac displayed a paternal-specific enrichment at the paternally expressed Igf2 locus, H3K79me3 was paternally biased at the maternally expressed H19 locus, including the paternally methylated imprinting control region (ICR). We found that these allele-specific differences depended on CTCF binding in the maternal ICR allele. We analyzed an additional 11 differentially methylated regions (DMRs) and found that, in general, H3K79me3 was associated with the CpG-methylated alleles, whereas H3K79me1, H3K79me2, and H4K91ac enrichment was specific to the unmethylated alleles. Our data suggest that allele-specific differences in the globular histone domains may constitute a layer of the "histone code" at imprinted genes.

  3. A Tale of Two Signals: AR and WNT in Development and Tumorigenesis of Prostate and Mammary Gland

    PubMed Central

    Pakula, Hubert; Xiang, Dongxi; Li, Zhe

    2017-01-01

    Prostate cancer (PCa) is one of the most common cancers and among the leading causes of cancer deaths for men in industrialized countries. It has long been recognized that the prostate is an androgen-dependent organ and PCa is an androgen-dependent disease. Androgen action is mediated by the androgen receptor (AR). Androgen deprivation therapy (ADT) is the standard treatment for metastatic PCa. However, almost all advanced PCa cases progress to castration-resistant prostate cancer (CRPC) after a period of ADT. A variety of mechanisms of progression from androgen-dependent PCa to CRPC under ADT have been postulated, but it remains largely unclear as to when and how castration resistance arises within prostate tumors. In addition, AR signaling may be modulated by extracellular factors among which are the cysteine-rich glycoproteins WNTs. The WNTs are capable of signaling through several pathways, the best-characterized being the canonical WNT/β-catenin/TCF-mediated canonical pathway. Recent studies from sequencing PCa genomes revealed that CRPC cells frequently harbor mutations in major components of the WNT/β-catenin pathway. Moreover, the finding of an interaction between β-catenin and AR suggests a possible mechanism of cross talk between WNT and androgen/AR signaling pathways. In this review, we discuss the current knowledge of both AR and WNT pathways in prostate development and tumorigenesis, and their interaction during development of CRPC. We also review the possible therapeutic application of drugs that target both AR and WNT/β-catenin pathways. Finally, we extend our review of AR and WNT signaling to the mammary gland system and breast cancer. We highlight that the role of AR signaling and its interaction with WNT signaling in these two hormone-related cancer types are highly context-dependent. PMID:28134791

  4. A Tale of Two Signals: AR and WNT in Development and Tumorigenesis of Prostate and Mammary Gland.

    PubMed

    Pakula, Hubert; Xiang, Dongxi; Li, Zhe

    2017-01-27

    Prostate cancer (PCa) is one of the most common cancers and among the leading causes of cancer deaths for men in industrialized countries. It has long been recognized that the prostate is an androgen-dependent organ and PCa is an androgen-dependent disease. Androgen action is mediated by the androgen receptor (AR). Androgen deprivation therapy (ADT) is the standard treatment for metastatic PCa. However, almost all advanced PCa cases progress to castration-resistant prostate cancer (CRPC) after a period of ADT. A variety of mechanisms of progression from androgen-dependent PCa to CRPC under ADT have been postulated, but it remains largely unclear as to when and how castration resistance arises within prostate tumors. In addition, AR signaling may be modulated by extracellular factors among which are the cysteine-rich glycoproteins WNTs. The WNTs are capable of signaling through several pathways, the best-characterized being the canonical WNT/β-catenin/TCF-mediated canonical pathway. Recent studies from sequencing PCa genomes revealed that CRPC cells frequently harbor mutations in major components of the WNT/β-catenin pathway. Moreover, the finding of an interaction between β-catenin and AR suggests a possible mechanism of cross talk between WNT and androgen/AR signaling pathways. In this review, we discuss the current knowledge of both AR and WNT pathways in prostate development and tumorigenesis, and their interaction during development of CRPC. We also review the possible therapeutic application of drugs that target both AR and WNT/β-catenin pathways. Finally, we extend our review of AR and WNT signaling to the mammary gland system and breast cancer. We highlight that the role of AR signaling and its interaction with WNT signaling in these two hormone-related cancer types are highly context-dependent.

  5. 40Ar 39Ar age constraints on neogene sedimentary beds, Upper Ramparts, half-way Pillar and Canyon village sites, Porcupine river, east-central Alaska

    USGS Publications Warehouse

    Kunk, M.J.; Rieck, H.; Fouch, T.D.; Carter, L.D.

    1994-01-01

    40Ar 39Ar ages of volcanic rocks are used to provide numerical constraints on the age of middle and upper Miocene sedimentary strata collected along the Porcupine River. Intercalated sedimentary rocks north of latitude 67??10???N in the Porcupine terrane of east-central Alaska contain a rich record of plant fossils. The fossils are valuable indicators of this interior region's paleoclimate during the time of their deposition. Integration of the 40Ar 39Ar results with paleomagnetic and sedimentological data allows for refinements in estimating the timing of deposition and duration of selected sedimentary intervals. 40Ar 39Ar plateau age spectra, from whole rock basalt samples, collected along the Upper Ramparts and near Half-way Pillar on the Porcupine River, range from 15.7 ?? 0.1 Ma at site 90-6 to 14.4 ?? 0.1 Ma at site 90-2. With exception of the youngest basalt flow at site 90-2, all of the samples are of reversed magnetic polarity, and all 40Ar 39Ar age spectrum results are consistent with the deposition of the entire stratigraphic section during a single interval of reversed magnetic polarity. The youngest flow at site 90-2 was emplaced during an interval of normal polarity. With age, paleomagnetic and sedimentological data, the ages of the Middle Miocene sedimentary rocks between the basalt flows at sites 90-1 and 90-2 can be assigned to an interval within the limits of analytical precision of 15.2 ?? 0.1 Ma; thus, the sediments were deposited during the peak of the Middle Miocene thermal maximum. Sediments in the upper parts of sites 90-1 and 90-2 were probably deposited during cooling from the Middle Miocene thermal maximum. 40Ar 39Ar results of plagioclase and biotite from a single tephra, collected at sites 90-7 and 90-8 along the Canyon Village section of the Porcupine River, indicate an age of 6.57 ?? 0.02 Ma for its time of eruption and deposition. These results, together with sedimentological and paleomagnetic data, suggest that all of the Upper

  6. Integration of Mobile AR Technology in Performance Assessment

    ERIC Educational Resources Information Center

    Kuo-Hung, Chao; Kuo-En, Chang; Chung-Hsien, Lan; Kinshuk; Yao-Ting, Sung

    2016-01-01

    This study was aimed at exploring how to use augmented reality (AR) technology to enhance the effect of performance assessment (PA). A mobile AR performance assessment system (MARPAS) was developed by integrating AR technology to reduce the limitations in observation and assessment during PA. This system includes three modules: Authentication, AR…

  7. 75 FR 29656 - Amendment of Class E Airspace; Magnolia, AR

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-27

    ... Federal Aviation Administration 14 CFR Part 71 Amendment of Class E Airspace; Magnolia, AR AGENCY: Federal... Magnolia, AR. Decommissioning of the Magnolia non-directional beacon (NDB) at Magnolia Municipal Airport, Magnolia, AR has made this action necessary to enhance the safety and management of Instrument Flight...

  8. 75 FR 66300 - Amendment of Class E Airspace; Searcy, AR

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-28

    ... Federal Aviation Administration 14 CFR Part 71 Amendment of Class E Airspace; Searcy, AR AGENCY: Federal... Searcy, AR. Decommissioning of the Searcy non-directional beacon (NDB) at Searcy Municipal Airport, Searcy, AR, has made this action necessary to enhance the safety and management of Instrument Flight...

  9. 75 FR 29655 - Amendment of Class E Airspace; Batesville, AR

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-27

    ... Federal Aviation Administration 14 CFR Part 71 Amendment of Class E Airspace; Batesville, AR AGENCY... airspace for Batesville, AR. Decommissioning of the Independence County non-directional beacon (NDB) at Batesville Regional Airport, Batesville, AR, has made this action necessary to enhance the safety...

  10. 75 FR 37291 - Amendment of Class E Airspace; Osceola, AR

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-29

    ... Federal Aviation Administration 14 CFR Part 71 Amendment of Class E Airspace; Osceola, AR AGENCY: Federal... Osceola, AR. Decommissioning of the Osceola non-directional beacon (NDB) at Osceola Municipal Airport has... rulemaking to amend Class E airspace for Osceola, AR, reconfiguring controlled airspace at Osceola...

  11. 75 FR 12161 - Establishment of Class E Airspace; Marianna, AR

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-15

    ... Federal Aviation Administration 14 CFR Part 71 Establishment of Class E Airspace; Marianna, AR AGENCY..., Marianna, AR, to accommodate new Standard Instrument Approach Procedures (SIAPs) at Marianna/Lee County... surface for SIAPs operations at Marianna/Lee County Airport-Steve Edwards Field, Marianna, AR....

  12. 75 FR 29657 - Establishment of Class E Airspace; Marianna, AR

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-27

    ... Federal Aviation Administration 14 CFR Part 71 Establishment of Class E Airspace; Marianna, AR AGENCY... airspace for Marianna, AR to accommodate Area Navigation (RNAV) Standard Instrument Approach Procedures (SIAPs) at Marianna/Lee County Airport--Steve Edwards Field, Marianna, AR. The FAA is taking this...

  13. 76 FR 73505 - Establishment of Class E Airspace; Nashville, AR

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-29

    ... TRANSPORTATION Federal Aviation Administration 14 CFR Part 71 Establishment of Class E Airspace; Nashville, AR... Class E airspace for Nashville, AR, to accommodate new Area Navigation (RNAV) Standard Instrument... Federal Register a notice of proposed rulemaking to amend Class E airspace for Nashville, AR,...

  14. 75 FR 29654 - Amendment of Class E Airspace; Manila, AR

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-27

    ... Federal Aviation Administration 14 CFR Part 71 Amendment of Class E Airspace; Manila, AR AGENCY: Federal... Manila, AR. Decommissioning of the Manila non-directional beacon (NDB) at Manila Municipal Airport, Manila, AR has made this action necessary to enhance the safety and management of Instrument Flight...

  15. Cooperation of Adhesin Alleles in Salmonella-Host Tropism

    PubMed Central

    De Masi, Leon; Yue, Min; Hu, Changmin; Rakov, Alexey V.; Rankin, Shelley C.

    2017-01-01

    ABSTRACT Allelic combinations and host specificities for three fimbrial adhesins, FimH, BcfD, and StfH, were compared for 262 strains of Salmonella enterica serovar Newport, a frequent human and livestock pathogen. Like FimH, BcfD had two major alleles (designated A and B), whereas StfH had two allelic groups, each with two alleles (subgroup A1 and A2 and subgroup B1 and B2). The most prevalent combinations of FimH/BcfD/StfH alleles in S. Newport were A/A/A1 and B/B/B1. The former set was most frequently found in bovine and porcine strains, whereas the latter combination was most frequently found in environmental and human isolates. Bacteria genetically engineered to express Fim, Bcf, or Stf fimbriae on their surface were tested with the different alleles for binding to human, porcine, and bovine intestinal epithelial cells. The major allelic combinations with bovine and porcine strains (A/A/A1) or with human isolates (B/B/B1) provided at least two alleles capable of binding significantly better than the other alleles to an intestinal epithelial cell line from the respective host(s). However, each combination of alleles kept at least one allele mediating binding to an intestinal epithelial cell from another host. These findings indicated that allelic variation in multiple adhesins of S. Newport contributes to bacterial adaptation to certain preferential hosts without losing the capacity to maintain a broad host range. IMPORTANCE Salmonella enterica remains a leading foodborne bacterial pathogen in the United States; infected livestock serve often as the source of contaminated food products. A study estimated that over a billion Salmonella gastroenteritis cases and up to 33 million typhoid cases occur annually worldwide, with 3.5 million deaths. Although many Salmonella strains with a broad host range present preferential associations with certain host species, it is not clear what determines the various levels of host adaptation. Here, causal properties of host

  16. Data Rich, Information Poor

    SciTech Connect

    Kaplan, P.G.; Rautman, C.A.

    1998-11-09

    Surviving in a data-rich environment means understanding the difference between data and information. This paper reviews an environmental case study that illustrates that understanding and shows its importance. In this study, a decision problem was stated in terms of au economic-objective fimction. The function contains a term that defines the stochastic relationship between the decision and the information obtained during field chamctetition for an environmental contaminant. Data is defied as samples drawn or experimental realizations of a mudom fimction. Information is defined as the quantitative change in the value of the objective fiction as a result of the sample.

  17. Call for Development of New Mineral Standards for 40Ar/39Ar Dating

    NASA Astrophysics Data System (ADS)

    Deino, A. L.; Turrin, B. D.; Renne, P. R.; Hemming, S. R.

    2015-12-01

    Age determination via the 40Ar/39Ar dating method relies on the intercomparison of measured 40Ar*/39ArK ratios of geological unknowns with those of co-irradiated mineral standards. Good analytical procedure dictates that these ratios (and the evolution of the Ar ion beams underpinning them) be as similar as practical for the greatest accuracy. Unfortunately, throughout several intervals of the geological time scale this 'best practice' cannot be achieved with existing widely used standards. Only two internationally utilized sanidine standards are available for the middle to late Cenozoic: the Alder Creek Rhyolite sanidine (ACs), at ~1.2 Ma (Turrin et al., 1994; Nomade et al., 2005), and the Fish Canyon Tuff sanidine (FCs) at ~28.2 Ma (e.g., Kuiper et al., 2008; Renne et al, 2011). The situation is even worse throughout much of the rest of the Phanerozoic, as the next oldest standard in common use is the Hb3gr hornblende standard with an age of ~1.1 Ga (Turner, 1971; Jourdan et al., 2006). We propose, as a community effort, the development a set of standards covering the entire target range of high-precision 40Ar/39Ar dating, i.e. the Phanerozoic. Their ages would be stepped in a regular fashion with no more than approximately a factor of 3 between standards, such that in the worse case the 40Ar*/39Ar ratios of standards and unknown need differ by no more than a factor of two. While somewhat arbitrary, an approximately 3 X age progression allows the entire time scale to be covered by a manageable number of standards. Anchoring the progression in the widely used ACs, FCs, and Hb3gr (in bold, below) yields the following set of suggested standard ages: 0.4, 1.2, 3.3, 9.4, 28.2, 95, 320, and 1100 Ma. A suitable standard should be highly reproducible in age at the grain-to-grain and sub-grain levels, and highly radiogenic. The mineral should be abundant and easily separated from the host rock. These criteria may be most easily achieved by focusing on sanidine phenocrysts

  18. Assignment of SNP allelic configuration in polyploids using competitive allele-specific PCR: application to citrus triploid progeny

    PubMed Central

    Cuenca, José; Aleza, Pablo; Navarro, Luis; Ollitrault, Patrick

    2013-01-01

    Background Polyploidy is a major component of eukaryote evolution. Estimation of allele copy numbers for molecular markers has long been considered a challenge for polyploid species, while this process is essential for most genetic research. With the increasing availability and whole-genome coverage of single nucleotide polymorphism (SNP) markers, it is essential to implement a versatile SNP genotyping method to assign allelic configuration efficiently in polyploids. Scope This work evaluates the usefulness of the KASPar method, based on competitive allele-specific PCR, for the assignment of SNP allelic configuration. Citrus was chosen as a model because of its economic importance, the ongoing worldwide polyploidy manipulation projects for cultivar and rootstock breeding, and the increasing availability of SNP markers. Conclusions Fifteen SNP markers were successfully designed that produced clear allele signals that were in agreement with previous genotyping results at the diploid level. The analysis of DNA mixes between two haploid lines (Clementine and pummelo) at 13 different ratios revealed a very high correlation (average = 0·9796; s.d. = 0·0094) between the allele ratio and two parameters [θ angle = tan−1 (y/x) and y′ = y/(x + y)] derived from the two normalized allele signals (x and y) provided by KASPar. Separated cluster analysis and analysis of variance (ANOVA) from mixed DNA simulating triploid and tetraploid hybrids provided 99·71 % correct allelic configuration. Moreover, triploid populations arising from 2n gametes and interploid crosses were easily genotyped and provided useful genetic information. This work demonstrates that the KASPar SNP genotyping technique is an efficient way to assign heterozygous allelic configurations within polyploid populations. This method is accurate, simple and cost-effective. Moreover, it may be useful for quantitative studies, such as relative allele-specific expression analysis and bulk segregant analysis

  19. Cosmic Ray Exposure Ages, Ar-Ar Ages, and the Origin and History of Eucrites

    NASA Technical Reports Server (NTRS)

    Wakefield, Kelli; Bogard, Donald; Garrison, Daniel

    2004-01-01

    HED meteorites likely formed at different depths on the large asteroid 4-Vesta, but passed through Vesta-derived, km-sized intermediary bodies (Vestoids), before arriving at Earth. Most eucrites and diogenites (and all howardites) are brecciated, and impact heating disturbed or reset the K-Ar ages (and some Rb-Sr ages) of most eucrites in the time period of approx. 3.4 - 4.1 Gyr ago. Some basaltic eucrites and most cumulate eucrites, however, are not brecciated. We recently showed that the Ar-39 - Ar-40 ages for several of these eucrites tightly cluster about a value of 4.48 +/- 0.02 Gyr, and we argue that this time likely represents a single large impact event on Vesta, which ejected these objects from depth and quenched their temperatures. A different parent body has been suggested for cumulate eucrites, although the Ar-Ar ages argue for a common parent. Similarities in the cosmic-ray (space) exposure ages for basaltic eucrites and diogenites also have been used to infer a common parent body for some HEDs. Here we present CRE ages of several cumulate and unbrecciated basaltic (UB) eucrites and compare these with CRE ages of other HEDs. This comparison also has some interesting implications for the relative locations of various HED types on Vesta and/or the Vestoids.

  20. First 40Ar/39Ar dating of intense Late Palaeogene lateritic weathering in Peninsular India

    NASA Astrophysics Data System (ADS)

    Bonnet, Nicolas J.; Beauvais, Anicet; Arnaud, Nicolas; Chardon, Dominique; Jayananda, Mudlappa

    2014-01-01

    Lateritic surface processes have shaped large platform and cratons of the tropical belt. Constraining the timing of such processes is crucial to decipher their role in cratonic morphogenesis and their response to long-term climatic change and lithospheric deformation. Weathering histories have been documented for South America, Africa and Australia, but precise time constraints of the lateritic weathering processes in South India are still lacking. We present 40Ar/39Ar ages of supergene cryptomelane (K-Mn oxide) formed in the Sandur Mn ore deposits exposed on the highest lateritic paleolandsurface that once covered the Mysore plateau and the adjacent Deccan Traps. Significant 40Ar/39Ar ages are estimated between ∼36 and ∼26 Ma from well-defined plateaus in step heating 39Ar release spectra and from best-fitted inverse isochrones. These ages constitute firm time constraints that document intense late Eocene-Oligocene lateritic weathering over Peninsular India under the influence of warm and wet climate comparable to that prevailing in tropical humid forests. These results imply that Southern India was weathered between ∼36 and 26 Ma and may have been dissected mostly in the Neogene.

  1. Measuring 36Ar without H35Cl interference

    NASA Astrophysics Data System (ADS)

    Saxton, John

    2015-04-01

    Noble gas measurements are usually made in static mode, when the mass spectrometer sensitivity is inversely proportional to volume: this makes the building of very large instruments to obtain high mass resolution impracticable. A particularly challenging interference has hitherto been H35Cl, which differs in mass from 36Ar by 1 part in 3937. We have developed a method which makes improved use of the available MRP to remove interferences, and used it to obtain HCl-free 36Ar measurements on a multicollector instrument with MRP of only ~6000 (MRP= mass resolving power = m/dm 5-95% on side of peak). By arranging that the target mass position on a minor isotope (e.g. 36Ar), from which the interference must be removed, coincides with the ~50% point on the side of a major isotope (e.g. 40Ar), it is possible both to set the mass accurately and to verify the mass position and stability during measurements. The peak top of 40Ar is measured in a separate mass step. Two small corrections are necessary. One compensates for the residual HCl tail at the 36Ar position. The other arises because the peak is not totally flat in the region of interest: 40Ar and 36Ar+HCl are measured on the peak top, whilst 36Ar is measured at the extreme edge, with slightly lower efficiency. The required correction parameters can be obtained from a series of air calibrations with different target/interference ratios. With samples containing 4x10-15to 3x10-14moles of 40Ar, 36Ar/40Ar was measured, without HCl interference, to a 1σ precision of 0.5%, only slightly worse than counting statistics. This is potentially useful for 40Ar/39Ar dating, where 36Ar is used to correct for trapped air, and may be particularly significant for smaller or younger samples.

  2. Generation of a Conditional Null Allele of Jumonji

    PubMed Central

    Mysliwiec, Matthew R.; Chen, Junqin; Powers, Patricia A.; Bartley, Christopher R.; Schneider, Michael D.; Lee, Youngsook

    2007-01-01

    Summary: The jumonji (jmj) gene plays important roles in multiple organ development in mouse, including cardiovascular development. Since JMJ is expressed widely during mouse development, it is essential that conditional knockout approaches be employed to ablate JMJ in a tissue-specific manner to identify the cell lineage specific roles of JMJ. In this report, we describe the establishment of a jmj conditional null allele in mice by generating a loxP-flanked (floxed) jmj allele, which allows the in vivo ablation of jmj via Cre recombinase-mediated deletion. Gene targeting was used to introduce loxP sites flanking exon 3 of the jmj allele to mouse embryonic stem cells. Our results indicate that the jmj floxed allele converts to a null allele in a heart-specific manner when embryos homozygous for the floxed jmj allele and carrying the α-myosin heavy chain promoter-Cre transgene were analyzed by Southern and Northern blot analyses. Therefore, this mouse line harboring the conditional jmj null allele will provide a valuable tool for deciphering the tissue and cell lineage specific roles of JMJ. PMID:16900512

  3. Allele Frequencies at Microsatellite Loci: The Stepwise Mutation Model Revisited

    PubMed Central

    Valdes, A. M.; Slatkin, M.; Freimer, N. B.

    1993-01-01

    We summarize available data on the frequencies of alleles at microsatellite loci in human populations and compare observed distributions of allele frequencies to those generated by a simulation of the stepwise mutation model. We show that observed frequency distributions at 108 loci are consistent with the results of the model under the assumption that mutations cause an increase or decrease in repeat number by one and under the condition that the product Nu, where N is the effective population size and u is the mutation rate, is larger than one. We show that the variance of the distribution of allele sizes is a useful estimator of Nu and performs much better than previously suggested estimators for the stepwise mutation model. In the data, there is no correlation between the mean and variance in allele size at a locus or between the number of alleles and mean allele size, which suggests that the mutation rate at these loci is independent of allele size. PMID:8454213

  4. Estimating relatedness and relationships using microsatellite loci with null alleles.

    PubMed

    Wagner, A P; Creel, S; Kalinowski, S T

    2006-11-01

    Relatedness is often estimated from microsatellite genotypes that include null alleles. When null alleles are present, observed genotypes represent one of several possible true genotypes. If null alleles are detected, but analyses do not adjust for their presence (ie, observed genotypes are treated as true genotypes), then estimates of relatedness and relationship can be incorrect. The number of loci available in many wildlife studies is limited, and loci with null alleles are commonly a large proportion of data that cannot be discarded without substantial loss of power. To resolve this problem, we present a new approach for estimating relatedness and relationships from data sets that include null alleles. Once it is recognized that the probability of the observed genotypes is dependent on the probabilities of a limited number of possible true genotypes, the required adjustments are straightforward. The concept can be applied to any existing estimators of relatedness and relationships. We review established maximum likelihood estimators and apply the correction in that setting. In an application of the corrected method to data from striped hyenas, we demonstrate that correcting for the presence of null alleles affect results substantially. Finally, we use simulated data to confirm that this method works better than two common approaches, namely ignoring the presence of null alleles or discarding affected loci.

  5. Ar-Ar Ages of L-Melt Rocks: Two Unusual Ages, and Some Insight into the Host of K

    NASA Astrophysics Data System (ADS)

    Weirich, J. R.; Isachsen, C.; Kring, D. A.; Swindle, T. D.

    2008-03-01

    Ar-Ar dating of two L-chondrite impact melts produce collisional ages of 4540 and ~50 Ma. Arrhenius plots rule out pyroxene as a second source of K. High temperature behavior of released Ar may be due to a phase change of feldspathic material.

  6. Paleotemperatures at the lunar surfaces from open system behavior of cosmogenic 38Ar and radiogenic 40Ar

    DOE PAGES

    Shuster, David L.; Cassata, William S.

    2015-02-10

    The simultaneous diffusion of both cosmogenic 38Ar and radiogenic 40Ar from solid phases is controlled by the thermal conditions of rocks while residing near planetary surfaces. Combined observations of 38Ar/37Ar and 40Ar/39Ar ratios during stepwise degassing analyses of neutron-irradiated Apollo samples can distinguish between diffusive loss of Ar due to solar heating of the rocks and that associated with elevated temperatures during or following impact events; the data provide quantitative constraints on the durations and temperatures of each process. From sequentially degassed 38Ar/37Ar ratios can be calculated a spectrum of apparent 38Ar exposure ages versus the cumulative release fraction ofmore » 37Ar, which is particularly sensitive to conditions at the lunar surface typically over ~106–108 year timescales. Due to variable proportions of K- and Ca-bearing glass, plagioclase and pyroxene, with variability in the grain sizes of these phases, each sample will have distinct sensitivity to, and therefore different resolving power on, past near-surface thermal conditions. Furthermore, we present the underlying assumptions, and the analytical and numerical methods used to quantify the Ar diffusion kinetics in multi-phase whole-rock analyses that provide these constraints.« less

  7. Structures of and allelic diversity and relationships among the major outer membrane protein (ompA) genes of the four chlamydial species.

    PubMed Central

    Kaltenboeck, B; Kousoulas, K G; Storz, J

    1993-01-01

    DNA sequences coding for 81% of the ompA gene from 24 chlamydial strains, representing all chlamydial species, were determined from DNA amplified by polymerase chain reactions. Chlamydial strains of serovars and strains with similar chromosomal restriction fragment length polymorphism had identical ompA DNA sequences. The ompA sequences were segregated into 23 different ompA alleles and aligned with each other, and phylogenetic relationships among them were inferred by neighbor-joining and maximum parsimony analyses. The neighbor-joining method produced a single phylogram which was rooted at the branch between two major clusters. One cluster included all Chlamydia trachomatis ompA alleles (trachoma group). The second cluster was composed of three major groups of ompA alleles: psittacosis group (alleles MN, 6BC, A22/M, B577, LW508, FEPN, and GPIC), pneumonia group (Chlamydia pneumoniae AR388 with the allele KOALA), and polyarthritis group (ruminant and porcine chlamydial alleles LW613, 66P130, L71, and 1710S with propensity for polyarthritis). These groups were distinguished through specific DNA sequence signatures. Maximum parsimony analysis yielded two equally most parsimonious phylograms with topologies similar to the ompA tree of neighbor joining. Two phylograms constructed from chlamydial genomic DNA distances had topologies identical to that of the ompA phylogram with respect to branching of the chlamydial species. Human serovars of C. trachomatis with essentially identical genomes represented a single taxonomic unit, while they were divergent in the ompA tree. Consistent with the ompA phylogeny, the porcine isolate S45, previously considered to be Chlamydia psittaci, was identified as C. trachomatis through biochemical characteristics. These data demonstrate that chlamydial ompA allelic relationships, except for human serovars of C. trachomatis, are cognate with chromosomal phylogenies. Images PMID:8419295

  8. Allele Mining and Selective Patterns of Pi9 Gene in a Set of Rice Landraces from India

    PubMed Central

    Imam, Jahangir; Mandal, Nimai P.; Variar, Mukund; Shukla, Pratyoosh

    2016-01-01

    Allelic variants of the broad-spectrum blast resistance gene, Pi9 (nucleotide binding site-leucine-rich repeat region) have been analyzed in Indian rice landraces. They were selected from the list of 338 rice landraces phenotyped in the rice blast nursery at central Rainfed Upland Rice Research Station, Hazaribag. Six of them were further selected on the basis of their resistance and susceptible pattern for virulence analysis and selective pattern study of Pi9 gene. The sequence analysis and phylogenetic study illustrated that such sequences are vastly homologous and clustered into two groups. All the blast resistance Pi9 alleles were grouped into one cluster, whereas Pi9 alleles of susceptible landraces formed another cluster even though these landraces have a low level of DNA polymorphisms. A total number of 136 polymorphic sites comprising of transitions, transversions, and insertion and deletions (InDels) were identified in the 2.9 kb sequence of Pi9 alleles. Lower variation in the form of mutations (77) (Transition + Transversion), and InDels (59) were observed in the Pi9 alleles isolated from rice landraces studied. The results showed that the Pi9 alleles of the selected rice landraces were less variable, suggesting that the rice landraces would have been exposed to less number of pathotypes across the country. The positive Tajima’s D (0.33580), P > 0.10 (not significant) was observed among the seven rice landraces, which suggests the balancing selection of Pi9 alleles. The value of synonymous substitution (-0.43337) was less than the non-synonymous substitution (0.78808). The greater non-synonymous substitution than the synonymous means that the coding region, mainly the leucine-rich repeat domain was under diversified selection. In this study, the Pi9 gene has been subjected to balancing selection with low nucleotide diversity which is different from the earlier reports, this may be because of the closeness of the rice landraces, cultivated in the same

  9. Regulation of AR Degradation and Function by Ubiquitylation

    DTIC Science & Technology

    2015-10-01

    assays to examine effects of site directed mutants on AR transcriptional activity. Lentiviruses encoding AR wild-type or mutants were used to establish...regulated Luciferase reporter gene then showed that only the K911A mutant AR had increased activity (~2-fold) (Fig. 1A). Table 1. AR...the stably expressed AR WT versus K911R mutant . As shown in figure 1B, the K911R mutant had increased activity in response to 1 nM DHT. Finally

  10. Direct dating of weathering phenomena by [sup 40]Ar/[sup 39]Ar and K-Ar analysis of supergene K-Mn oxides

    SciTech Connect

    Vasconcelos, P.M.; Brimhall, G.H. ); Renne, P.R.; Becker, T.A. )

    1994-03-01

    Potassium-bearing manganese oxides, cryptomelane, K[sub 1-2](Mn[sup 3+]Mn[sup 4+])[sub 8] O[sub 16] [center dot] xH[sub 2]O, and hollandite, (K,Ba)[sub 1-2](Mn[sup 3+],Mn[sup 4+])[sub 8] O[sub 16] [center dot] xH[sub 2]O, are often authigenically precipitated in weathering profiles. Dating of these phases allows timing of the progression of oxidation fronts during weathering and pedogenic processes. Potential problems in manganese oxide dating, such as Ar and/or K losses, excess argon, [sup 39]Ar loss by recoil during neutron irradiation, etc. are addressed. The K-Ar and [sup 40]Ar/[sup 39]Ar analytical results indicate that Ar and/or K losses, excess [sup 40]Ar, and [sup 39]Ar recoil seem not to pose problems in manganese oxide dating. This investigation suggests that the fine scale, laser-probe [sup 40]Ar/[sup 39]Ar technique is most appropriate for dating of weathering phenomena because this technique permits identification of contaminating phases and the presence of multiple generations of weathering minerals in the inherently complex mineral assemblage characteristic of weathering profiles. K-Ar and [sup 40]Ar/[sup 39]Ar dating of supergene K-bearing manganese oxides formed during lateritization of Archean and Proterozoic bedrocks in the Carajas Region, Amazonia, Brazil, indicates that weathering started before 72 [+-] 6 Ma. Petrographic, electron microscope, and electron microprobe investigation reveal multiple generations of manganese oxide precipitation. Age clusters at 65-69, 51-56, 40-43, 33-35, 20, 24, 12-17 Ma, and zero-age (0.2 [+-] 0.2 Ma) suggest episodic precipitation of K-Mn oxides resulting form changing weathering conditions in the Amazon throughout the Cenozoic. K-Ar and [sup 40]Ar/[sup 39]Ar dating of supergene cryptomelane from weathering profiles in eastern Minas Gerais, southeastern Brazil, suggests continuous weathering from 10 to 5.6 Ma ago, possibly reflecting local climatic conditions due to the proximity with the Atlantic Ocean.

  11. Laser /39/Ar-/40/Ar dating of two clasts from consortium breccia 73215

    NASA Technical Reports Server (NTRS)

    Eichhorn, G.; Schaeffer, O. A.; James, O. B.; Mueller, H. W.

    1978-01-01

    A laser Ar-39-Ar-40 study of the components of an ANT-suite anorthositic gabbro and a black aphanite from a consortium breccia is reported. A wide range of K-Ar ages is found for the plagioclase in the anorthositic gabbro; at the centers of the largest grains is material showing the greatest age (older than 4.11 billion years) while the youngest material (3.81-3.88 billion years) is found near the grain margins. Partial outgassing of the clasts upon incorporation into the breccia could account for the age patterns. The black aphanite clast appears to be cogenetic with the aphanite that forms the breccia matrix. The time of crystallization of a lunar granite has also been measured by the laser technique.

  12. Incremental Heating 40Ar/39Ar Analyses of Mono Basin Tephra

    NASA Astrophysics Data System (ADS)

    Deino, A.; Hemming, S. R.; Ali, G. A.; Zimmerman, S. R.; Turrin, B. D.

    2012-12-01

    The glacially and volcanically derived sediments of the Wilson Creek Formation (Lajoie, 1968), Mono Basin, eastern California, contain an invaluable archive of hydroclimatic, volcanic, and paleomagnetic events encompassing the past ~85 ka. Accurate radioisotopic dating of this sequence, however, has been stymied by systematic problems encountered in applying C-14, U/Th, and 40Ar/39Ar methods. 40Ar/39Ar dating of the 19-plus locally derived tephra horizons within the formation has been foiled by the presence of excess argon, incorporation of older crystal components and by the difficulty of accurately measuring of the age of late Quaternary materials (Chen et al., 1996; Kent et al., 2002; Cassata et al., 2011). We have acquired detailed laser step-heating 40Ar/39Ar age spectra on individual sanidine crystals of several Wilson Creek ashes using the multiple ion counter capability of the BGC Noblesse noble gas mass spectrometer. This approach represents a breakthrough for young materials, as it allows examination of the internal argon systematics of each grain and identification of steps representing excess Ar components as distinct from primary volcanic ages. Typically, anomalously old ages occur in the first 10-50% of the 39Ar release, followed by an age 'plateau' that is generally consistent from grain to grain. This methodological advance is a result of improvements in extraction-line design and mass spectrometer manufacture (in particular, improved source ionization efficiency, utilization of low-noise ion counters, and fully simultaneous data collection of all relevant isotopes). For example, 15 single-grain step-heating experiments (8-13 steps each) have been performed on sanidine from Ash 12. All crystals yielded apparent-age plateaus in the latter stages of the release, often preceded by anomalously old steps. While the age distribution of the plateau results are unimodal and consistent, with a weighted-mean age of 42.1 ± 0.3 ka (0.7% 1σ error), the

  13. Ar-Ar and Rb-Sr Ages of the Tissint Olivine-phyric Martian Shergottite

    NASA Technical Reports Server (NTRS)

    Park, J.; Herzog, G. F.; Nyquist, L. E.; Shih, C.-Y.; Turin, B.; Lindsay, F. N.; Delaney, J. S.; Swisher, C. C., III; Agee, C.

    2013-01-01

    The fifth martian meteorite fall, Tissint, is an olivine-phyric shergottite that contains olivine macrocrysts (approximately 1.5 mm) [1]. [2] reported the Sm-Nd age of Tissint as 596 plus or minus 23 Ma along with Rb-Sr data that defined no isochron. [3] reported Lu-Hf and Sm-Nd ages of 583 plus or minus 86 Ma and 616 plus or minus 67 Ma, respectively. The cosmic-ray exposure ages of Tissint are 1.10 plus or minus 0.15 Ma based on 10Be [4], and 1.0-1.1 Ma, based on 3He, 21Ne, and 38Ar [5,6].We report Ar-Ar ages and Rb-Sr data.

  14. Potential energy surface and bound states of the NH3-Ar and ND3-Ar complexes.

    PubMed

    Loreau, J; Liévin, J; Scribano, Y; van der Avoird, A

    2014-12-14

    A new, four-dimensional potential energy surface for the interaction of NH3 and ND3 with Ar is computed using the coupled-cluster method with single, double, and perturbative triple excitations and large basis sets. The umbrella motion of the ammonia molecule is explicitly taken into account. The bound states of both NH3-Ar and ND3-Ar are calculated on this potential for total angular momentum values from J = 0 to 10, with the inclusion of Coriolis interactions. The energies and splittings of the rovibrational levels are in excellent agreement with the extensive high-resolution spectroscopic data accumulated over the years in the infrared and microwave regions for both complexes, which demonstrates the quality of the potential energy surface.

  15. Ar-40/Ar-39 ages of six Apollo 15 impact melt rocks by laser step heating

    NASA Technical Reports Server (NTRS)

    Dalrymple, G. B.; Ryder, Graham

    1991-01-01

    Fifteen high resolution (21-51 step) Ar-40/Ar-39 age spectra are obtained for six Apollo 15 impact melt rocks of different compositions, using a continuous laser system on submilligram subsamples and on single crystal plagioclase clasts. Four of the six samples gave reproducible age spectra with well-defined intermediate temperature plateaus over 48 percent or more of the Ar-39 released; the plateaus are interpreted as crystallization ages. Samples 15304,7,69, 15294,6,21 and 15314,26,156 gave virtually identical plateau ages whose weighted mean is 3870 + or - 6 Ma. These three melt rocks differ in composition and likely formed in three separate impact events.

  16. Ar-40/Ar-39 dating of collisional events in chondrite parent bodies

    NASA Technical Reports Server (NTRS)

    Bogard, D. D.; Wright, R. J.; Husain, L.

    1976-01-01

    Ar-40/Ar-39 age dating of a number of shocked ordinary chondrites is interpreted in terms of collisional degassing events of meteorite parent bodies, probably in the asteroid belt. Examples of L, H, and at least one LL chondrite show episodic degassing. Degassing ages suggest several distinct events ranging from about 0.03 aeon to 0.7 aeon and probably higher. All specimens of either the H or L chondrites are not consistent with a single age event. A direct correlation exists between the degree of shock heating and the fraction of argon lost during degassing. However, no chondrite yet analyzed shows complete degassing of its high-temperature phase. Consequently, whole rock K-Ar ages are not accurate monitors of the time of the shock event.

  17. Ar-Ar and I-XE Ages and the Thermal History of IAB Meteorites

    NASA Technical Reports Server (NTRS)

    Bogard, Donald D.; Garrison, Daniel H.; Takeda, Hiroshi

    2006-01-01

    Studies of several samples of the large Caddo County IAB iron meteorite reveal andesitic material, enriched in Si, Na, Al and Ca which is essentially unique among meteorites. This material is believed to have formed from a chondritic source by partial melting and to have further segregated by grain coarsening. Such an origin implies extended metamorphism of the IAB parent body. New Ar-39- Ar-40 ages for silicate from three different Caddo samples are consistent with a common age of 4.50- 4.51 Gyr ago. Less well defined Ar-Ar degassing ages for inclusions from two other IABs, EET8333 and Udei Station, are approx. 4.32 Gyr, whereas the age for Campo del Cielo varies considerably over approx. 3.23-4.56 Gyr. New I-129-Xe-129 ges for Caddo County and EET8333 are 4561.9 plus or minus 0.1 Myr and 4560-4563 Myr, respectively, relative to an age of 4566 Myr for Shallowater. Considering all reported Ar-Ar ages for IABs and related winonaites, the range is approx. 4.32-4.53 Gyr, but several IABs give similar Ar ages of 4.50-4.52 Gyr. We interpret these older ages to represent cooling after the time of last significant metamorphism on the parent body, and the younger ages to represent later 40Ar diffusion loss. These older Ar-Ar ages are similar to Sm-Nd and Rb-Sr isochron ages reported in the literature for Caddo County. Considering the possibility that IAB parent body formation was followed by impact disruption, reassembly, and metamorphism (e.g., Benedix et al. 2000), the time of the postassembly metamorphism may have been as late as approx. 4.53 Gyr ago. However, precise I-Xe ages reported for some IABs define a range of ages of approx. 4560 to approx. 4576 Myr. The older I-Xe ages exceed the oldest precise radiometric ages of meteorites, appear unrealistic, and suggest a bias in the calibration of all I-Xe ages. But even with such a bias, the I-Xe ages of IABs cannot easily be reconciled with the much younger Ar-Ar and Sm-Nd ages and with cooling rates deduced from Ni

  18. Ar-Ar and I-Xe Ages and the Thermal History of IAB Meteorites

    NASA Technical Reports Server (NTRS)

    Bogard, Donald D.; Garrison, Daniel H.; Takeda, Hiroshi

    2004-01-01

    Studies of several samples of the large Caddo County IAB iron meteorite reveal andesitic material, enriched in Si, Na, Al and Ca, which is essentially unique among meteorites. This material is believed to have formed from a chondritic source by partial melting and to have further segregated by grain coarsening. Such an origin implies extended metamorphism of the IAB parent body. New Ar-39-Ar-40 ages for silicate from three different Caddo samples are consistent with a common age of 4.50-4.51 Gyr ago. Less well defined Ar-Ar degassing ages for inclusions from two other IABs, EET8333 and Udei Station, are approx.4.32 Gyr, whereas the age for Campo del Cielo varies considerably over approx.3.23-4.56 Gyr. New I-129-Xe-129 ages for Caddo County and EET8333 are 4561.9+/-0.1 Myr and 4560- 4563 Myr, respectively, relative to an age of 4566 Myr for Shallowater. Considering all reported Ar-Ar ages for IABs and related winonaites, the range is approx.4.32-4.53 Gyr, but several IABs give similar Ar ages of 4.50-4.52 Gyr. We interpret these older ages to represent cooling after the time of last significant metamorphism on the parent body, and the younger ages to represent later Ar-40 diffusion loss. These older Ar-Ar ages are similar to Sm-Nd and Rb-Sr isochron ages reported in the literature for Caddo County. Considering the possibility that IAB parent body formation was followed by impact disruption, reassembly, and metamorphism (e.g., Benedix et al. 2000), the time of the post-assembly metamorphism may have been as late as approx.4.53 Gyr ago. However, precise I-Xe ages reported for some IABs define a range of ages of approx.4560 to approx.4576 Myr. The older I-Xe ages exceed the oldest precise radiometric ages of meteorites, appear unrealistic, and s,uggest a bias in the calibration of all I-Xe ages. But even with such a bias, the I-Xe ages of IABs cannot easily be reconciled with the much younger Ar-Ar and Sm-Nd ages and with cooling rates deduced from Ni concentration

  19. Ar-Ar and I-Xe Ages and the Thermal History of IAB Meteorites

    NASA Technical Reports Server (NTRS)

    Bogard, Donald D.; Garrison, Daniel H.; Takeda, Hiroshi

    2004-01-01

    Studies of several samples of the large Caddo County IAB iron meteorite reveal andesitic material, enriched in Si, Nay Al and Ca, which is essentially unique among meteorites. This material is believed to have formed from a chondritic source by partial melting and to have further segregated by grain coarsening. Such an origin implies extended metamorphism of the IAB parent body. New Ar-39-Ar-40 ages for silicate from three different Caddo samples are consistent with a common age of 4.50- 4.51 Gyr ago. Less well defined Ar-Ar degassing ages for inclusions from two other IABs, EET8333 and Udei Station, are approx.4.32 Gyr, whereas the age for Campo del Cielo varies considerably over approx.3.23-4.56 Gyr. New I-129-Xe-129 ages for Caddo County and EET8333 are 4561.9 +/-0.1 Myr and 4560-4563 Myr, respectively, relative to an age of 4566 Myr for Shallowater. Considering all reported Ar-Ar ages for IABs and related winonaites, the range is approx.4.32-4.53 Gyr, but several IABs give similar Ar ages of 4.50-4.52 Gyr. We interpret these older ages to represent cooling after the time of last significant metamorphism on the parent body, and the younger ages to represent later Ar-40 diffusion loss. These older Ar-Ar ages are similar to Sm-Nd and Rb-Sr isochron ages reported in the literature for Caddo County. Considering the possibility that IAB parent body formation was followed by impact disruption, reassembly, and metamorphism (e.g., Benedix et al. 2000), the time of the post-assembly metamorphism may have been as late as approx.4.53 Gyr ago. However, precise I-Xe ages reported for some IABs define a range of ages of approx.4560 to approx.4576 My. The older I-Xe ages exceed the oldest precise radiometric ages of meteorites, appear unrealistic, and suggest a bias in the calibration of all I-Xe ages. But even with such a bias, the I-Xe ages of IABs cannot easily be reconciled with the much younger Ar-Ar and Sm-Nd ages and with cooling rates deduced from Ni concentration

  20. Investigation of the Gardnos Impact Structure: 40Ar/39Ar Results

    NASA Astrophysics Data System (ADS)

    Grier, J. A.; Swindle, T. D.; Kring, D. A.; Melosh, H. J.

    1995-09-01

    Introduction: The Gardnos structure (Norway) [1], has recently been identified as an impact crater [2,3], despite being deformed by a series of tectonic processes [2]. The age of the structure is uncertain, although attempts to date the impact event have been made on the basis of stratigraphic relationships [2,3]. Unfortunately, these estimates differ by more than 100 million years. The first study suggested that the impact corresponded roughly with the Cambro-Ordovician boundary, ~500 Ma [2], while a second stratigraphic interpretation suggested a Precambrian age of 650 Ma [3]. To try and resolve this discrepancy, we attempted to determine the age of the structure with radiometric techniques, which typically have an error of < 10 Ma. Method: We examined three samples from the crater, in an attempt to determine the age using the 40Ar/39Ar dating method. The samples (plagioclase feldspar, alkali feldspar, and shards of gray, semi-transparent, glassy-looking material) were obtained from the suevite breccia unit of [2]. This unit should be the most promising for 40Ar/39Ar dating, since it is melt bearing, and no other unit is likely to be less affected by subsequent tectonism and sedimentation. Results: Our experiments yielded complicated age spectra interpreted to reflect a thermal event at 385+/-5 Ma and another possible event at 312+/-5 Ma (Fig. 1). All three samples yielded similar results. If the stratigraphic interpretations are correct, it thus seems clear that the impact event itself was not dated. The 385 Ma age corresponds to the end of the Caledonian Orogeny, which significantly altered this section of Norway [4]. It is suspected that late Caledonian folding occurred during this time [4], and we therefore interpret the 385 Ma age as the thermal metamorphic overprint of the Caledonian Orogeny. Another event clearly occurred afterwards, which is responsible for the 312 Ma signature. The cause of this thermal overprint has not yet been identified, since

  1. Quantifying RNA allelic ratios by microfluidic multiplex PCR and sequencing.

    PubMed

    Zhang, Rui; Li, Xin; Ramaswami, Gokul; Smith, Kevin S; Turecki, Gustavo; Montgomery, Stephen B; Li, Jin Billy

    2014-01-01

    We developed a targeted RNA sequencing method that couples microfluidics-based multiplex PCR and deep sequencing (mmPCR-seq) to uniformly and simultaneously amplify up to 960 loci in 48 samples independently of their gene expression levels and to accurately and cost-effectively measure allelic ratios even for low-quantity or low-quality RNA samples. We applied mmPCR-seq to RNA editing and allele-specific expression studies. mmPCR-seq complements RNA-seq for studying allelic variations in the transcriptome.

  2. The ChArMEx database

    NASA Astrophysics Data System (ADS)

    Ferré, Helene; Belmahfoud, Nizar; Boichard, Jean-Luc; Brissebrat, Guillaume; Descloitres, Jacques; Fleury, Laurence; Focsa, Loredana; Henriot, Nicolas; Mastrorillo, Laurence; Mière, Arnaud; Vermeulen, Anne

    2014-05-01

    The Chemistry-Aerosol Mediterranean Experiment (ChArMEx, http://charmex.lsce.ipsl.fr/) aims at a scientific assessment of the present and future state of the atmospheric environment in the Mediterranean Basin, and of its impacts on the regional climate, air quality, and marine biogeochemistry. The project includes long term monitoring of environmental parameters, intensive field campaigns, use of satellite data and modelling studies. Therefore ChARMEx scientists produce and need to access a wide diversity of data. In this context, the objective of the database task is to organize data management, distribution system and services, such as facilitating the exchange of information and stimulating the collaboration between researchers within the ChArMEx community, and beyond. The database relies on a strong collaboration between OMP and ICARE data centres and has been set up in the framework of the Mediterranean Integrated Studies at Regional And Locals Scales (MISTRALS) program data portal. All the data produced by or of interest for the ChArMEx community will be documented in the data catalogue and accessible through the database website: http://mistrals.sedoo.fr/ChArMEx. At present, the ChArMEx database contains about 75 datasets, including 50 in situ datasets (2012 and 2013 campaigns, Ersa background monitoring station), 25 model outputs (dust model intercomparison, MEDCORDEX scenarios), and a high resolution emission inventory over the Mediterranean. Many in situ datasets have been inserted in a relational database, in order to enable more accurate data selection and download of different datasets in a shared format. The database website offers different tools: - A registration procedure which enables any scientist to accept the data policy and apply for a user database account. - A data catalogue that complies with metadata international standards (ISO 19115-19139; INSPIRE European Directive; Global Change Master Directory Thesaurus). - Metadata forms to document

  3. MEIS1 functions as a potential AR negative regulator

    SciTech Connect

    Cui, Liang; Yang, Yutao; Hang, Xingyi; Cui, Jiajun; Gao, Jiangping

    2014-10-15

    The androgen receptor (AR) plays critical roles in human prostate carcinoma progression and transformation. However, the activation of AR is regulated by co-regulators. MEIS1 protein, the homeodomain transcription factor, exhibited a decreased level in poor-prognosis prostate tumors. In this study, we investigated a potential interaction between MEIS1 and AR. We found that overexpression of MEIS1 inhibited the AR transcriptional activity and reduced the expression of AR target gene. A potential protein–protein interaction between AR and MEIS1 was identified by the immunoprecipitation and GST pull-down assays. Furthermore, MEIS1 modulated AR cytoplasm/nucleus translocation and the recruitment to androgen response element in prostate specific antigen (PSA) gene promoter sequences. In addition, MEIS1 promoted the recruitment of NCoR and SMRT in the presence of R1881. Finally, MEIS1 inhibited the proliferation and anchor-independent growth of LNCaP cells. Taken together, our data suggests that MEIS1 functions as a novel AR co-repressor. - Highlights: • A potential interaction was identified between MEIS1 and AR signaling. • Overexpression of MEIS1 reduced the expression of AR target gene. • MEIS1 modulated AR cytoplasm/nucleus translocation. • MEIS1 inhibited the proliferation and anchor-independent growth of LNCaP cells.

  4. K/Ar dating of lunar soils. II

    NASA Technical Reports Server (NTRS)

    Alexander, E. C., Jr.; Bates, A.; Coscio, M. R., Jr.; Dragon, J. C.; Murthy, V. R.; Pepin, R. O.; Venkatesan, T. R.

    1976-01-01

    An attempt is made to identify those K/Ar techniques which extract the most reliable chronological information from lunar soils and to define the situations in which the best data are obtainable. Results are presented for determinations of the exposure and K/Ar ages of five lunar soil samples, which were performed by applying correlation techniques for a two-component argon structure to stepwise-heated and neutron-irradiated aliquots of grain-sized separates. It is found that ages deduced from Ar-40/surface-correlated Ar-36 vs K-40/surface-correlated Ar-36 and analogous plots of data from grain-sized separates appear to be the best available K/Ar ages of submature to mature lunar soils, that ages deduced from Ar-40 vs Ar-36 and analogous plots which assume a uniform K content can be significantly in error, and that stepwise-heating (Ar-40)-(Ar-39) experiments yield useful information only for simple immature soils where the K-Ar systematics are dominated by a single component.

  5. AR-Signaling in Human Malignancies: Prostate Cancer and Beyond

    PubMed Central

    Schweizer, Michael T.; Yu, Evan Y.

    2017-01-01

    In the 1940s Charles Huggins reported remarkable palliative benefits following surgical castration in men with advanced prostate cancer, and since then the androgen receptor (AR) has remained the main therapeutic target in this disease. Over the past couple of decades, our understanding of AR-signaling biology has dramatically improved, and it has become apparent that the AR can modulate a number of other well-described oncogenic signaling pathways. Not surprisingly, mounting preclinical and epidemiologic data now supports a role for AR-signaling in promoting the growth and progression of several cancers other than prostate, and early phase clinical trials have documented preliminary signs of efficacy when AR-signaling inhibitors are used in several of these malignancies. In this article, we provide an overview of the evidence supporting the use of AR-directed therapies in prostate as well as other cancers, with an emphasis on the rationale for targeting AR-signaling across tumor types. PMID:28085048

  6. AR-Signaling in Human Malignancies: Prostate Cancer and Beyond.

    PubMed

    Schweizer, Michael T; Yu, Evan Y

    2017-01-11

    In the 1940s Charles Huggins reported remarkable palliative benefits following surgical castration in men with advanced prostate cancer, and since then the androgen receptor (AR) has remained the main therapeutic target in this disease. Over the past couple of decades, our understanding of AR-signaling biology has dramatically improved, and it has become apparent that the AR can modulate a number of other well-described oncogenic signaling pathways. Not surprisingly, mounting preclinical and epidemiologic data now supports a role for AR-signaling in promoting the growth and progression of several cancers other than prostate, and early phase clinical trials have documented preliminary signs of efficacy when AR-signaling inhibitors are used in several of these malignancies. In this article, we provide an overview of the evidence supporting the use of AR-directed therapies in prostate as well as other cancers, with an emphasis on the rationale for targeting AR-signaling across tumor types.

  7. Ar-Ar Dating of Martian Chassignites, NWA2737 and Chassigny, and Nakhlite MIL03346

    NASA Technical Reports Server (NTRS)

    Bogard, D. D.; Garrison, D. H.

    2006-01-01

    Until recently only three nakhlites and one chassignite had been identified among martian meteorites. These four exhibit very similar radiometric ages and cosmic ray exposure (CRE) ages, indicating that they may have derived from a common location on Mars and were ejected into space by a single impact. This situation is quite different from that of martian shergottites, which exhibit a range of radiometric ages and CRE ages (1). Recently, several new nakhlites and a new martian dunite (NWA2737) have been recognized. Here we report our results of Ar-39-Ar-40 dating for the MIL03346 nakhlite and the NWA2737 "chassignite", along with new results on Chassigny.

  8. Significance of the cosmogenic argon correction in deciphering the 40Ar/39Ar ages of the Nakhlite (Martian) meteorites

    NASA Astrophysics Data System (ADS)

    Cohen, B. E.; Cassata, W.; Mark, D. F.; Tomkinson, T.; Lee, M. R.; Smith, C. L.

    2015-12-01

    All meteorites contain variable amounts of cosmogenic 38Ar and 36Ar produced during extraterrestrial exposure, and in order to calculate reliable 40Ar/39Ar ages this cosmogenic Ar must be removed from the total Ar budget. The amount of cosmogenic Ar has usually been calculated from the step-wise 38Ar/36Ar, minimum 36Ar/37Ar, or average 38Arcosmogenic/37Ar from the irradiated meteorite fragment. However, if Cl is present in the meteorite, then these values will be disturbed by Ar produced during laboratory neutron irradiation of Cl. Chlorine is likely to be a particular issue for the Nakhlite group of Martian meteorites, which can contain over 1000 ppm Cl [1]. An alternative method for the cosmogenic Ar correction uses the meteorite's exposure age as calculated from an un-irradiated fragment and step-wise production rates based on the measured Ca/K [2]. This calculation is independent of the Cl concentration. We applied this correction method to seven Nakhlites, analyzed in duplicate or triplicate. Selected samples were analyzed at both Lawrence Livermore National Laboratory and SUERC to ensure inter-laboratory reproducibility. We find that the cosmogenic argon correction of [2] has a significant influence on the ages calculated for individual steps, particularly for those at lower temperatures (i.e., differences of several tens of million years for some steps). The lower-temperature steps are more influenced by the alternate cosmogenic correction method of [2], as these analyses yielded higher concentrations of Cl-derived 38Ar. As a result, the Nakhlite data corrected using [2] yields step-heating spectra that are flat or nearly so across >70% of the release spectra (in contrast to downward-stepping spectra often reported for Nakhlite samples), allowing for the calculation of precise emplacement ages for these meteorites. [1] Cartwright J. A. et al. (2013) GCA, 105, 255-293. [2] Cassata W. S., and Borg L. E. (2015) 46th LPSC, Abstract #2742.

  9. Finding Structure in the ArXiv

    NASA Astrophysics Data System (ADS)

    Alemi, Alexander; Chachra, Ricky; Ginsparg, Paul; Sethna, James

    2014-03-01

    We applied machine learning techniques to the full text of the arXiv articles and report a meaningful low-dimensional representation of this big dataset. Using Google's open source implementation of the continuous skip-gram model, word2vec, the vocabulary used in scientific articles is mapped to a Euclidean vector space that preserves semantic and syntactic relationships between words. This allowed us to develop techniques for automatically characterizing articles, finding similar articles and authors, and segmenting articles into their relevant sections, among other applications.

  10. Microsatellites in the estrogen receptor (ESR1, ESR2) and androgen receptor (AR) genes and breast cancer risk in African American and Nigerian women.

    PubMed

    Zheng, Yonglan; Huo, Dezheng; Zhang, Jing; Yoshimatsu, Toshio F; Niu, Qun; Olopade, Olufunmilayo I

    2012-01-01

    Genetic variants in hormone receptor genes may be crucial predisposing factors for breast cancer, and microsatellites in the estrogen receptor (ESR1, ESR2) and androgen receptor (AR) genes have been suggested to play a role. We studied 258 African-American (AA) women with breast cancer and 259 hospital-based controls, as well as 349 Nigerian (NG) female breast cancer patients and 296 community controls. Three microsatellites, ESR1_TA, ESR2_CA and AR_CAG, in the ESR1, ESR2 and AR genes, respectively, were genotyped. Their repeat lengths were then analyzed as continuous and dichotomous variables. Analyses of continuous variables showed no association with breast cancer risk in either AA or NG at ESR1_TA; AA cases had shorter repeats in the long allele of ESR2_CA than AA controls (Mann-Whitney P= 0.036; logistic regression P = 0.04, OR= 0.91, 95% CI 0.83-1.00), whereas NG patients had longer repeats in the short allele than NG controls (Mann-Whitney P= 0.0018; logistic regression P= 0.04, OR= 1.06, 95% CI 1.00-1.11); and AA cases carried longer repeats in the short allele of AR_CAG than AA controls (Mann-Whitney P= 0.038; logistic regression P = 0.03, OR= 1.08, 95% CI 1.01-1.15). When allele sizes were categorized as dichotomous variables, we discovered that women with two long alleles of ESR2_CA had increased risk of breast cancer (OR = 1.38, 95% CI 1.10-1.74; P = 0.006). This is the first study to investigate these three microsatellites in hormonal receptor genes in relation to breast cancer risk in an indigenous African population. After adjusting for multiple-testing, our findings suggest that ESR2_CA is associated with breast cancer risk in Nigerian women, whereas ESR1_TA and AR_CAG seem to have no association with the disease among African American or Nigerian women.

  11. Unveiling Turrialba (Costa Rica) volcano's latest geological evolution through new 40Ar/39Ar, ages

    NASA Astrophysics Data System (ADS)

    Ruiz Cubillo, P.; Turrin, B. D.; Soto, G. J.; Del Potro, R.; Gagnevin, D.; Gazel, E.; Mora Fernandez, M.; Carr, M. J.; Swisher, C. C.

    2010-12-01

    Step-heating 40Ar/39Ar dating experiments on whole rock matrix were performed on samples from eight key lava flow units from Turrialba, the easternmost volcano of the Central Volcanic Range of Costa Rica. Our results, together with available corrected 14C ages, recent mapping and new geochemical analyses, are part of a study to reconstruct Turrialba’s evolution. The project is being conducted as part of wider studies because of the increase in volcanic activity during the last three years. The geochemical compositions of the lava flow units span the range from basalts to dacites, and commonly have high K2O concentrations, making them good candidates for 40Ar/39Ar radiometric dating. The ages reported here correspond to the Paleo Turrialba (600-250 ka) and Neo Turrialba (< 250 ka) temporal stages. Sample TUR-38 (251 ± 4 ka) belongs to the latest unit of Paleo Turrialba stage, known as Finca Liebres volcano, while the remaining seven samples belong to Neo Turrialba: TUR-30 (99 ± 3 ka), TUR-19 (90 ± 4 ka), TUR-32 (62 ± 2 ka) TUR-33 (61 ± 2 ka), TUR-12 (25 ± 1.9 ka), TUR-36 (10 ± 3 ka) and TUR-08 (3 ± 3 ka). All the obtained ages in this study are in agreement with the local stratigraphy and prior 14C age determinations, adding robustness to our results. According to ages obtained and the areal distribution of the sampled units, the most important construction period of the massif was during the Neo-Turrialba stage which has passed through two important constructing episodes, around 100-60 ka and 10 ka-present. Although our results include some very young ages, all of them meet the established evaluation criteria used for plateau and isochron ages, commonly used for 40Ar/39Ar dating. Furthermore, we used a protocol that closely monitors the mass spectrometer mass discrimination during the measurements to provide additional control. Three of the eight 40Ar/39Ar ages reported here are remarkably young (25 ka or less). Two of those are the samples with the

  12. Analysis and interpretation of short tandem repeat microvariants and three-banded allele patterns using multiple allele detection systems.

    PubMed

    Crouse, C A; Rogers, S; Amiott, E; Gibson, S; Masibay, A

    1999-01-01

    The Palm Beach County Sheriffs Office (PBSO) Crime Laboratory and the Alabama Department of Forensic Sciences (ADFS) have validated and implemented analysis of short tandem repeat (STR) sequences on casework using silver staining kit and SYBR Green I detection systems and are presently validating fluorescently tagged STR alleles using the Hitachi FMBIO 100 instrument. Concurrently, the Broward County Sheriff's Office (BSO) Crime Laboratory is validating the ABI Prism310 Genetic Analyzer capillary electrophoresis STR detection system (ABI CE310) from Perkin Elmer Applied BioSystems. During the course of analyzing over 10,000 individuals for the STR loci CSF1PO, TPOX and THO1 (CTT) using silver staining for allele detection, 42 samples demonstrated alleles that were "off ladder," contained three-banded patterns at a single locus, or exhibited an apparent THO1 "9.3,10" allele pattern. PBSO, ADFS and BSO Crime Laboratories have collaborated on the verification of the allele patterns observed in these 42 samples using the following allele detection systems: (1) manual silver staining, (2) SYBR Green I staining, and/or (3) fluorescently tagged amplified products separated by polyacrylamide gel electrophoresis or capillary electrophoresis followed by laser detection. Regardless of the CTT allele detection system utilized, concordant results were obtained for 41 of the 42 samples. The only exception was a sample in which a wide band within the THO1 locus was identified as a THO1 "9.3, 10" genotype by silver staining kit and SYBR Green I staining but was verified to be a THO1 "9.3" homozygote by all other allele detection systems. Manual allele detection could readily identify microvariants, as a visual assessment of stained gels clearly shows that alleles do not migrate coincident with well-characterized allele size standards. As would be predicted, however, the manual detection systems did not provide adequate resolution to approximate the basepair size for off

  13. A New Electrophoresis Technique to Seperate Microsatellite Alleles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Traditional agarose and polyacrylamide gel electrophoresis have been used commonly for microsatellite (simple sequence repeats, SSRs) analysis, but they are labor- intensive and not always able to provide accurate sizes for different alleles. Capillary sequencers provide automated analysis and accur...

  14. Genetic mapping of the interface between the ArsD metallochaperone and the ArsA ATPase

    PubMed Central

    Yang, Jianbo; Ajees, Abdul; Salam, Abdul; Rosen, Barry P.

    2011-01-01

    Summary The ArsD metallochaperone delivers trivalent metalloids, As(III) or Sb(III), to the ArsA ATPase, the catalytic subunit of the ArsAB As(III) efflux pump. Transfer of As(III) increases the affinity of ArsA for As(III), allowing resistance to environmental arsenic concentrations. As(III) transfer is channeled from chaperone to ATPase, implying that ArsD and ArsA form an interface at their metal binding sites. A genetic approach was used to test this hypothesis. Thirteen ArsD mutants exhibiting either weaker or stronger interaction with ArsA were selected by either repressed transactivator yeast two-hybrid or reverse yeast two-hybrid assays. Additionally, Lys-37 and Lys-62 were identified as being involved in ArsD function by site-directed mutagenesis and chemical modification. Substitution at either position with arginine was tolerated, suggesting participation of a positive charge. By yeast two-hybrid analysis K37A and K62A mutants lost interaction with ArsA. All fifteen mutations were mapped on the surface of the ArsD structure, and their locations are consistent with a structural model generated by in silico docking. Four are close to metalloid binding site residues Cys-12, Cys-13 and Cys18, and seven are on the surface of helix 1. These results suggest that the interface involves one surface of helix 1 and the metalloid binding site. PMID:21299644

  15. The role of mitochondrial fusion and StAR phosphorylation in the regulation of StAR activity and steroidogenesis.

    PubMed

    Castillo, Ana F; Orlando, Ulises; Helfenberger, Katia E; Poderoso, Cecilia; Podesta, Ernesto J

    2015-06-15

    The steroidogenic acute regulatory (StAR) protein regulates the rate-limiting step in steroidogenesis, i.e. the delivery of cholesterol from the outer (OMM) to the inner (IMM) mitochondrial membrane. StAR is a 37-kDa protein with an N-terminal mitochondrial targeting sequence that is cleaved off during mitochondrial import to yield 30-kDa intramitochondrial StAR. StAR acts exclusively on the OMM and its activity is proportional to how long it remains on the OMM. However, the precise fashion and the molecular mechanism in which StAR remains on the OMM have not been elucidated yet. In this work we will discuss the role of mitochondrial fusion and StAR phosphorylation by the extracellular signal-regulated kinases 1/2 (ERK1/2) as part of the mechanism that regulates StAR retention on the OMM and activity.

  16. Robust identification of local adaptation from allele frequencies.

    PubMed

    Günther, Torsten; Coop, Graham

    2013-09-01

    Comparing allele frequencies among populations that differ in environment has long been a tool for detecting loci involved in local adaptation. However, such analyses are complicated by an imperfect knowledge of population allele frequencies and neutral correlations of allele frequencies among populations due to shared population history and gene flow. Here we develop a set of methods to robustly test for unusual allele frequency patterns and correlations between environmental variables and allele frequencies while accounting for these complications based on a Bayesian model previously implemented in the software Bayenv. Using this model, we calculate a set of "standardized allele frequencies" that allows investigators to apply tests of their choice to multiple populations while accounting for sampling and covariance due to population history. We illustrate this first by showing that these standardized frequencies can be used to detect nonparametric correlations with environmental variables; these correlations are also less prone to spurious results due to outlier populations. We then demonstrate how these standardized allele frequencies can be used to construct a test to detect SNPs that deviate strongly from neutral population structure. This test is conceptually related to FST and is shown to be more powerful, as we account for population history. We also extend the model to next-generation sequencing of population pools-a cost-efficient way to estimate population allele frequencies, but one that introduces an additional level of sampling noise. The utility of these methods is demonstrated in simulations and by reanalyzing human SNP data from the Human Genome Diversity Panel populations and pooled next-generation sequencing data from Atlantic herring. An implementation of our method is available from http://gcbias.org.

  17. Sequencing of 15 new BoLA-DRB3 alleles.

    PubMed

    Wang, K; Sun, D; Zhang, Y

    2008-08-01

    The class II DR of bovine major histocompatibility complex of cattle (BoLA) plays a central role in the regulation of the immune response through their ability to present those peptides to T-cell receptors. In this work, we sequenced the exon2 of DRB3 to identify new alleles in Chinese yellow cattle, a total of 15 new BoLA-DRB3 alleles were found.

  18. DRD4 dopamine receptor allelic diversity in various primate species

    SciTech Connect

    Adamson, M.; Higley, D.; O`Brien, S.

    1994-09-01

    The DRD4 dopamine receptor is uniquely characterized by a 48 bp repeating segment within the coding region, located in exon III. Different DRD4 alleles are produced by the presence of additional 48 bp repeats, each of which adds 16 amino acids to the length of the 3rd intracytoplasmic loop of the receptor. The DRD4 receptor is therefore an intriguing candidate gene for behaviors which are influenced by dopamine function. In several human populations, DRD4 alleles with 2-8 and 10 repeats have previously been identified, and the 4 and 7 repeat alleles are the most abundant. We have determined DRD4 genotypes in the following nonhuman primate species: chimpanzee N=2, pygmy chimpanzee N=2, gorilla N=4, siamang N=2, Gelada baboon N=1, gibbon N=1, orangutan (Bornean and Sumatran) N=62, spider monkey N=4, owl monkey N=1, Colobus monkey N=1, Patas monkey N=1, ruffed lemur N=1, rhesus macaque N=8, and vervet monkey N=28. The degree of DRD4 polymorphism and which DRD4 alleles were present both showed considerable variation across primate species. In contrast to the human, rhesus macaque monkeys were monomorphic. The 4 and 7 repeat allels, highly abundant in the human, may not be present in certain other primates. For example, the four spider monkeys we studied showed the 7, 8 and 9 repeat length alleles and the only gibbon we analyzed was homozygous for the 9 repeat allele (thus far not observed in the human). Genotyping of other primate species and sequencing of the individual DRD4 repeat alleles in different species may help us determine the ancestral DRD4 repeat length and identify connections between DRD4 genotype and phenotype.

  19. SSR allelic variation in almond (Prunus dulcis Mill.).

    PubMed

    Xie, Hua; Sui, Yi; Chang, Feng-Qi; Xu, Yong; Ma, Rong-Cai

    2006-01-01

    Sixteen SSR markers including eight EST-SSR and eight genomic SSRs were used for genetic diversity analysis of 23 Chinese and 15 international almond cultivars. EST- and genomic SSR markers previously reported in species of Prunus, mainly peach, proved to be useful for almond genetic analysis. DNA sequences of 117 alleles of six of the 16 SSR loci were analysed to reveal sequence variation among the 38 almond accessions. For the four SSR loci with AG/CT repeats, no insertions or deletions were observed in the flanking regions of the 98 alleles sequenced. Allelic size variation of these loci resulted exclusively from differences in the structures of repeat motifs, which involved interruptions or occurrences of new motif repeats in addition to varying number of AG/CT repeats. Some alleles had a high number of uninterrupted repeat motifs, indicating that SSR mutational patterns differ among alleles at a given SSR locus within the almond species. Allelic homoplasy was observed in the SSR loci because of base substitutions, interruptions or compound repeat motifs. Substitutions in the repeat regions were found at two SSR loci, suggesting that point mutations operate on SSRs and hinder the further SSR expansion by introducing repeat interruptions to stabilize SSR loci. Furthermore, it was shown that some potential point mutations in the flanking regions are linked with new SSR repeat motif variation in almond and peach.

  20. Mutable R-Navajo Alleles of Cyclic Origin in Maize

    PubMed Central

    Brink, R. Alexander; Williams, Elizabeth

    1973-01-01

    The generation in cyclic fashion of 26 mutable R-Navajo (mRnj) alleles in maize involved transposition of a non-specific repressor of gene action, Modulator (Mp), first away from, and then back to, the R locus represented by the R-Navajo (Rnj) allele on chromosome 10. The mRnj alleles reconstituted in this way varied widely, and continuously, in mutability to Rnj—that is, in transposition of Mp away from the R locus, thus derepressing the Rnj gene. They were alike, or nearly so, however, in activating Ds chromosome breakage and in increasing the stability of variegated pericarp, another unstable compound allele comprising Mp conjoined with Prr on chromosomal 1. These latter two phenomena are based primarily on loci elsewhere in the genome. It is postulated that the 26 reconstituted mRnj alleles carry a common Mp which, however, is intercalated at a different site within each allele. Nucleotide sequence in the regions adjacent to Mp is assumed to determine the frequency with which a form of micro-nondisjunction occurs whereby Mp is released from a donor site. Transposition to a new site is interpreted in terms of a chromosome model that gives effect to nicking, or single strand breaks, occurring throughout the genome as a prerequisite to unwinding, strand separation, and replication, of the DNA double helix. PMID:17248592

  1. Allele-specific MMP-3 transcription under in vivo conditions

    SciTech Connect

    Zhu Chaoyong; Odeberg, Jacob; Hamsten, Anders; Eriksson, Per . E-mail: Per.Eriksson@ki.se

    2006-09-29

    A common matrix metalloproteinases-3 (MMP-3) -1612 5A/6A promoter polymorphism is associated with risk for cardiovascular disease, rheumatoid arthritis, and other diseases. Here we used the haplotype chromatin immunoprecipitation method to study allele-specific MMP-3 expression under in vivo conditions in heterozygous THP-1 cells. Pyrosequencing was used to analyse the ratio of 5A-allele to 6A-allele after chromatin immunoprecipitation using an antibody against phosphorylated active RNA polymerase II. There was no allele-specific difference in transcriptional activity during basal conditions, i.e., in unstimulated monocytic THP-1 cells. However, after stimulation of MMP-3 expression by monocyte differentiation or incubation with IL-1{beta}, the haplotype containing the 5A-allele was associated with higher transcriptional activity compared with the 6A-containing haplotype. Electromobility shift assay demonstrated increased binding of nuclear proteins to the 5A-allele after monocyte differentiation. In conclusion, the common MMP-3 5A/6A promoter polymorphism appears to be functional only during specific environmental conditions involving inflammation.

  2. Overdominant alleles in a population of variable size.

    PubMed Central

    Slatkin, M; Muirhead, C A

    1999-01-01

    An approximate method is developed to predict the number of strongly overdominant alleles in a population of which the size varies with time. The approximation relies on the strong-selection weak-mutation (SSWM) method introduced by J. H. Gillespie and leads to a Markov chain model that describes the number of common alleles in the population. The parameters of the transition matrix of the Markov chain depend in a simple way on the population size. For a population of constant size, the Markov chain leads to results that are nearly the same as those of N. Takahata. The Markov chain allows the prediction of the numbers of common alleles during and after a population bottleneck and the numbers of alleles surviving from before a bottleneck. This method is also adapted to modeling the case in which there are two classes of alleles, with one class causing a reduction in fitness relative to the other class. Very slight selection against one class can strongly affect the relative frequencies of the two classes and the relative ages of alleles in each class. PMID:10353917

  3. Evidence for shock heating and constraints on Martian surface temperatures revealed by 40Ar/ 39Ar thermochronometry of Martian meteorites

    NASA Astrophysics Data System (ADS)

    Cassata, William S.; Shuster, David L.; Renne, Paul R.; Weiss, Benjamin P.

    2010-12-01

    The thermal histories of Martian meteorite are important for the interpretation of petrologic, geochemical, geochronological, and paleomagnetic constraints that they provide on the evolution of Mars. In this paper, we quantify 40Ar/ 39Ar ages and Ar diffusion kinetics of Martian meteorites Allan Hills (ALH) 84001, Nakhla, and Miller Range (MIL) 03346. We constrain the thermal history of each meteorite and discuss the resulting implications for their petrology, paleomagnetism, and geochronology. Maskelynite in ALH 84001 yields a 40Ar/ 39Ar isochron age of 4163 ± 35 Ma, which is indistinguishable from recent Pb-Pb ( Bouvier et al., 2009a) and Lu-Hf ages ( Lapen et al., 2010). The high precision of this result arises from clear resolution of a reproducible trapped 40Ar/ 36Ar component in maskelynite in ALH 84001 ( 40Ar/ 36Ar = 632 ± 90). The maskelynite 40Ar/ 39Ar age predates the Late Heavy Bombardment and likely represents the time at which the original natural remanent magnetization (NRM) component observed in ALH 84001 was acquired. Nakhla and MIL 03346 yield 40Ar/ 39Ar isochron ages of 1332 ± 24 and 1339 ± 8 Ma, respectively, which we interpret to date crystallization. Multi-phase, multi-domain diffusion models constrained by the observed Ar diffusion kinetics and 40Ar/ 39Ar age spectra suggest that localized regions within both ALH 84001 and Nakhla were intensely heated for brief durations during shock events at 1158 ± 110 and 913 ± 9 Ma, respectively. These ages may date the marginal melting of pyroxene in each rock, mobilization of carbonates and maskelynite in ALH 84001, and NRM overprints observed in ALH 84001. The inferred peak temperatures of the shock heating events (>1400 °C) are sufficient to mobilize Ar, Sr, and Pb in constituent minerals, which may explain some of the dispersion observed in 40Ar/ 39Ar, Rb-Sr, and U-Th-Pb data toward ages younger than ˜4.1 Ga. The data also place conservative upper bounds on the long-duration residence

  4. Ionization in 0.1-1.6 MeV Ar +-Kr and Kr +-Ar collisions

    NASA Astrophysics Data System (ADS)

    Zarcone, M. J.; Lincoln, B. A.; Rapposch, M. H.; Reed, K. J.; Antar, A. A.; Kessel, Q. C.

    1989-04-01

    The final charge states of ions scattered to large angles (1° -18°) in Ar +-Kr and Kr +-Ar collisions have been measured for collision energies from 0.1 to 1.6 MeV. Both sets of data show stepwise increases in ionization beginning for those collisions having distances of closest approach of 0.7 and 0.4 a.u. For the smallest distances of closest approach reached (0.05 a.u.), the average number of electrons lost from the collision complex totals nearly twenty. Comparison with molecular orbital calculations shows possible electron promotions to exist for the 0.7 and 0.4 a.u. distances; however, comparison of the Ar-Kr and Kr-Ar data sets with the calculations shows that a variety of separated-atom states may participate in the promotions. This is in contrast to existing models for deeper-lying shells in which specific separated-atom-united-atom correlations are thought to exist.

  5. Rb Sr, Sm Nd and Ar Ar isotopic systematics of Martian dunite Chassigny

    NASA Astrophysics Data System (ADS)

    Misawa, K.; Shih, C.-Y.; Reese, Y.; Bogard, D. D.; Nyquist, L. E.

    2006-06-01

    Isotopic analysis of the Martian meteorite Chassigny yields a Rb-Sr age of 1406 ± 14 Ma with an initial 87Sr/ 86Sr ratio of 0.702251 ± 0.000034, a Sm-Nd age of 1386 ± 28 Ma with an initial ɛ143Nd-value of + 16.9 ± 0.3 and an 39Ar- 40Ar age of 1360 + 40 - 20 Ma. The concordance of these ages and the Rb-Sr and Sm-Nd initial isotopic signatures suggest that Chassigny crystallized from low Rb/Sr, light rare earth element depleted source materials ˜ 1390 Ma ago. The ages and ɛ143Nd-values of Chassigny and the nakhlites Governador Valadares and Lafayette overlap, suggesting that they could have come from very similar mantle sources. Nakhla, Northwest Africa 998 and Yamato 000593 appear to be from similar but distinct sources. Chassigny and all nakhlites so far studied have undergone similar evolution histories. That is, chassignites/nakhlites were derived from a region where volcanism lasted at least 50 Ma and crystallized from different lava flows or subsurface sills. They probably were launched from Mars by a single impact event. The trapped Martian atmospheric 40Ar/ 36Ar ratios in Chassigny, nakhlites and shergottite impact glass are similar and possibly indicate minimal change in this ratio over the past ≥ 600 Ma.

  6. Strong multiple-capture effect in slow Ar^17+-Ar collisions: a quantum mechanical analysis

    NASA Astrophysics Data System (ADS)

    Salehzadeh, Arash; Kirchner, Tom

    2012-10-01

    A recent X-ray spectroscopy experiment on 255 keV Ar^17+-Ar collisions [1] provided evidence for strong multiple-electron capture --- a feature that is supported by classical trajectory Monte Carlo calculations for similar collision systems [2]. We have coupled a quantum-mechanical independent-electron model calculation for the Ar^17+-Ar system with (semi-) phenomenological Auger and radiative cascade models to test these findings. The capture calculations are performed using the basis generator method and include single-particle states on the projectile up to the 10th shell. The cross sections obtained for shell-specific multiple capture are fed into a stabilization scheme proposed in Ref. [3] in order to obtain n-specific cross sections for apparent single (and double) capture that in turn are fed into a radiative cascade code [1] to obtain X-ray emission intensities that can be compared with the experimental data. Good agreement is found for the Lyman series from n=3 to n=7 if the multiple-capture contributions are included, whereas calculations that ignore them are in stark conflict with the data. [4pt] [1] M. Trassinelli et al., J. Phys. B 45, 085202 (2012)[0pt] [2] S. Otranto and R. Olson, Phys. Rev. A 83, 032710 (2011)[0pt] [3] R. Ali et al., Phys. Rev A 49, 3586 (1994).

  7. Resonant proton scattering on 46Ar using the Active-Target Time Projection Chamber

    NASA Astrophysics Data System (ADS)

    Bradt, J.; Ahn, T.; Ayyad Limonge, Y.; Bazin, D.; Beceiro Novo, S.; Carpenter, L.; Kuchera, M. P.; Lynch, W.; Mittig, W.; Rost, S.; Watwood, N.; Barney, J.; Datta, U.; Estee, J.; Gillibert, A.; Manfredi, J.; Morfouace, P.; Perez Loureiro, D.; Pollacco, E.; Sammut, J.; Sweany, S.

    2016-09-01

    A well-known technique for studying the single-particle properties of neutron-rich nuclei is to use resonant proton scattering on a parent nucleus to populate the isobaric analog states of the corresponding neutron-rich nucleus. The locations and amplitudes of these resonances are directly related to the structure of the nucleus of interest by isospin symmetry. We performed an experiment of this type at the National Superconducting Cyclotron Laboratory to commission the recently completed Active-Target Time Projection Chamber (AT-TPC). A 4.6-MeV/u radioactive beam of 46Ar was injected into the AT-TPC. The detector was filled with isobutane gas-which provided the protons for the reaction and served as the tracking medium-and placed inside a 2-T magnetic field. We will present preliminary results from this experiment and discuss the benefits of the active-target method for this type of measurement.

  8. cAMP stimulation of StAR expression and cholesterol metabolism is modulated by co-expression of labile suppressors of transcription and mRNA turnover.

    PubMed

    Jefcoate, Colin R; Lee, Jinwoo; Cherradi, Nadia; Takemori, Hiroshi; Duan, Haichuan

    2011-04-10

    The steroidogenic acute regulatory (StAR) protein is generated in rodents from 1.6 kb and 3.5 kb mRNA formed by alternative polyadenylation. The zinc finger protein, TIS11B (also Znf36L1), is elevated by cAMP in adrenal cells in parallel with StAR mRNA. TIS11b selectively destabilizes the 3.5 kb mRNA through AU-rich sequences at the end of the 3'UTR. siRNA suppression shows that TIS11b surprisingly increases StAR protein and cholesterol metabolism. StAR transcription is directly activated by PKA phosphorylation. cAMP responsive element binding (CREB) protein 1 phosphorylation is a key step leading to recruitment of the co-activator, CREB binding protein (CBP). A second protein, CREB regulated transcription coactivator (TORC/CRTC), enhances this recruitment, but is inhibited by salt inducible kinase (SIK). Basal StAR transcription is constrained through this phosphorylation of TORC. PKA provides an alternative stimulation by phosphorylating SIK, which prevents TORC inactivation. PKA stimulation of StAR nuclear transcripts substantially precedes TORC recruitment to the StAR promoter, which may, therefore, mediate a later step in mRNA production. Inhibition of SIK by staurosporine elevates StAR transcription and TORC recruitment to maximum levels, but without CREB phosphorylation. TORC suppression by SIK evidently limits basal StAR transcription. Staurosporine and cAMP stimulate synergistically. SIK targets the phosphatase, PP2a (activation), and Type 2 histone de-acetylases (inhibition), which may each contribute to suppression. Staurosporine stimulation through SIK inhibition is repeated in cAMP stimulation of many steroidogenic genes regulated by steroidogenic factor 1 (SF-1) and CREB. TIS11b and SIK may combine to attenuate StAR expression when hormonal stimuli decline.

  9. 40Ar/39Ar geochronology of submarine Mauna Loa volcano, Hawaii

    NASA Astrophysics Data System (ADS)

    Jicha, Brian R.; Rhodes, J. Michael; Singer, Brad S.; Garcia, Michael O.

    2012-09-01

    New geochronologic constraints refine the growth history of Mauna Loa volcano and enhance interpretations of the petrologic, geochemical, and isotopic evolution of Hawaiian magmatism. We report results of 40Ar/39Ar incremental heating experiments on low-K, tholeiitic lavas from the 1.6 km high Kahuku landslide scarp cutting Mauna Loa's submarine southwest rift zone, and from lavas in a deeper section of the rift. Obtaining precise40Ar/39Ar ages from young, tholeiitic lavas containing only 0.2-0.3 wt.% K2O is challenging due to their extremely low radiogenic 40Ar contents. Analyses of groundmass from 45 lavas yield 14 new age determinations (31% success rate) with plateau and isochron ages that agree with stratigraphic constraints. Lavas collected from a 1250 m thick section in the landslide scarp headwall were all erupted around 470 ± 10 ka, implying an extraordinary period of accumulation of ˜25 mm/yr, possibly correlating with the peak of the shield-building stage. This rate is three times higher than the estimated vertical lava accumulation rate for shield-building at Mauna Kea (8.6 ± 3.1 mm/yr) based on results from the Hawaii Scientific Drilling Project. Between ˜470 and 273 ka, the lava accumulation rate along the southwest rift zone decreased dramatically to ˜1 mm/yr. We propose that the marked reduction in lava accumulation rate does not mark the onset of post-shield volcanism as previously suggested, but rather indicates the upward migration of the magma system as Mauna Loa evolved from a submarine stage of growth to one that is predominantly subaerial, thereby cutting off supply to the distal rift zone. Prior to ˜250 ka, lavas with Loihi-like isotopic signatures were erupted along with lavas having typical Mauna Loa values, implying greater heterogeneity in the plume source earlier in Mauna Loa's growth. In addition to refining accumulation rates and the isotopic evolution of the lavas erupted along the southwest rift zone, our new40Ar/39Ar results

  10. The 40Ar/39Ar and K/Ar dating of lavas from the Hilo 1-km core hole, Hawaii Scientific Drilling Project

    USGS Publications Warehouse

    Sharp, W.D.; Turrin, B.D.; Renne, P.R.; Lanphere, M.A.

    1996-01-01

    Mauna Kea lava flows cored in the HilIo hole range in age from <200 ka to about 400 ka based on 40Ar/39Ar incremental heating and K-Ar analyses of 16 groundmass samples and one coexisting plagioclase. The lavas, all subaerially deposited, include a lower section consisting only of tholeiitic basalts and an upper section of interbedded alkalic, transitional tholeiitic, and tholeiitic basalts. The lower section has yielded predominantly complex, discordant 40Ar/39Ar age spectra that result from mobility of 40Ar and perhaps K, the presence of excess 40Ar, and redistribution of 39Ar by recoil. Comparison of K-Ar ages with 40Ar/39Ar integrated ages indicates that some of these samples have also lost 39Ar. Nevertheless, two plateau ages of 391 ?? 40 and 400 ?? 26 ka from deep in the hole, combined with data from the upper section, show that the tholeiitic section accumulated at an average rate of about 7 to 8 m/kyr and has an mean recurrence interval of 0.5 kyr/flow unit. Samples from the upper section yield relatively precise 40Ar/39Ar plateau and isotope correlation ages of 326 ?? 23, 241 ?? 5, 232 ?? 4, and 199 ?? 9 ka for depths of -415.7 m to -299.2 m. Within their uncertainty, these ages define a linear relationship with depth, with an average accumulation rate of 0.9 m/kyr and an average recurrence interval of 4.8 kyr/flow unit. The top of the Mauna Kea sequence at -280 m must be older than the plateau age of 132 ?? 32 ka, obtained for the basal Mauna Loa flow in the corehole. The upward decrease in lava accumulation rate is a consequence of the decreasing magma supply available to Mauna Kea as it rode the Pacific plate away from its magma source, the Hawaiian mantle plume. The age-depth relation in the core hole may be used to test and refine models that relate the growth of Mauna Kea to the thermal and compositional structure of the mantle plume.

  11. 40Ar/39Ar dating of tourmaline as a tool for high-temperature metamorphism thermochronology

    NASA Astrophysics Data System (ADS)

    Jourdan, Fred; Thern, Eric

    2014-05-01

    Tourmaline is an ubiquitous mineral, with properties making it ideal for studying metamorphic processes as well as a useful tool for a wide range of applications (e.g, magmatism, metasomatism, ore deposits [1]), mostly because it is not sensitive to chemical or mechanical alteration and is stable over a wide range of pressure-temperature conditions (up to 6 GPa and 850° C [2]). Typical metamorphic tourmaline types include dravite and shorl which, along with elbaite, belong to the alkali group [1]. The alkali group is notable because tourmalines from this group tend to incorporate trace amounts of K2O and therefore, can be dated using the 40Ar/39Ar technique. In order to understand the maximum temperature below which the K/Ar chronometer stays closed to argon loss by thermally activated diffusion, we carried out temperature controlled furnace diffusion experiments on well-behaved 40Ar/39Ar plateau-forming Archean tourmaline of 2935 ± 9 Ma [3]. Each experiment yielded an Arrhenius profile (Do vs. 1/temperature) that shows that the 39Ar data form two linear arrays with two distinct slopes. The first array only includes a few % of the total gas, has a shallow slope and shows very fast diffusivity at low temperature. We interpret these data as indicating very fast release of argon by cracks and defects. The second array of data points includes most of the gas of each experiment and forms a much steeper slope. These data yielded Ea (activation energy) values ranging from 120 to 157 Kcal/mol and D0 (pre-exponential diffusion factor) values ranging from 1.9x106 to 2.5x109 cm2/s for crystals with an average radius of 100 ± 25 μm. Three additional experiments using a laser (resulting in poor temperature control) suggest similar values although the latter experiments are considered semi-quantitative. The furnace experiments suggest that tourmaline has a weighted mean closure temperature of 804 ± 90 ° C (1σ) for a cooling rate of 10° C/Ma. Monte Carlo simulations using

  12. Impriniting of human H19: Allele-specific CpG methylation, loss of the active allele in Wilms tumor, and potential for somatic allele switching

    SciTech Connect

    Zhang, Y.; Shields, T.; Crenshaw, T.; Hao, Y.; Moulton, T.; Tycko, B. )

    1993-07-01

    Genomic imprinting and monoallelic gene expression appear to play a role in human genetic disease and tumorigenesis. The human H19 gene, at chromosome 11p15, has previously been shown to be monoallelically expressed. Since CpG methylation has been implicated in imprinting, the authors analyzed methylation of H19 DNA. In fetal and adult organs the transcriptionally silent H19 allele was extensively hypermethylated through the entire gene and its promoter, and, consistent with a functional role for DNA methylation, expression of an H19 promoter-reporter construct was inhibited by in vitro methylation. Gynogenetic ovarian teratomas were found to contain only hypomethylated H19 DNA, suggesting that the expressed H19 allele might be maternal. This was confirmed by analysis of 11p15 polymorphisms in a patient with Wilms tumor. The tumor had lost the maternal 11p15, and H19 expression in the normal kidney was exclusively from this allele. Imprinting of human H19 appears to be susceptible to tissue-specific modulation in somatic development; in one individual, cerebellar cells were found to express only the otherwise silent allele. Implications of these findings for the role of DNA methylation in imprinting and for H19 as a candidate imprinted tumor-suppressor gene are discussed. 57 refs., 7 figs.

  13. Androgen Receptor-Mediated Growth Suppression of HPr-1AR and PC3-Lenti-AR Prostate Epithelial Cells

    PubMed Central

    Bolton, Eric C.

    2015-01-01

    The androgen receptor (AR) mediates the developmental, physiologic, and pathologic effects of androgens including 5α-dihydrotestosterone (DHT). However, the mechanisms whereby AR regulates growth suppression and differentiation of luminal epithelial cells in the prostate gland and proliferation of malignant versions of these cells are not well understood, though they are central to prostate development, homeostasis, and neoplasia. Here, we identify androgen-responsive genes that restrain cell cycle progression and proliferation of human prostate epithelial cell lines (HPr-1AR and PC3-Lenti-AR), and we investigate the mechanisms through which AR regulates their expression. DHT inhibited proliferation of HPr-1AR and PC3-Lenti-AR, and cell cycle analysis revealed a prolonged G1 interval. In the cell cycle, the G1/S-phase transition is initiated by the activity of cyclin D and cyclin-dependent kinase (CDK) complexes, which relieve growth suppression. In HPr-1AR, cyclin D1/2 and CDK4/6 mRNAs were androgen-repressed, whereas CDK inhibitor, CDKN1A, mRNA was androgen-induced. The regulation of these transcripts was AR-dependent, and involved multiple mechanisms. Similar AR-mediated down-regulation of CDK4/6 mRNAs and up-regulation of CDKN1A mRNA occurred in PC3-Lenti-AR. Further, CDK4/6 overexpression suppressed DHT-inhibited cell cycle progression and proliferation of HPr-1AR and PC3-Lenti-AR, whereas CDKN1A overexpression induced cell cycle arrest. We therefore propose that AR-mediated growth suppression of HPr-1AR involves cyclin D1 mRNA decay, transcriptional repression of cyclin D2 and CDK4/6, and transcriptional activation of CDKN1A, which serve to decrease CDK4/6 activity. AR-mediated inhibition of PC3-Lenti-AR proliferation occurs through a similar mechanism, albeit without down-regulation of cyclin D. Our findings provide insight into AR-mediated regulation of prostate epithelial cell proliferation. PMID:26372468

  14. Distribution of BoLA-DRB3 allelic frequencies and identification of two new alleles in Iranian buffalo breed.

    PubMed

    Mosafer, J; Heydarpour, M; Manshad, E; Russell, G; Sulimova, G E

    2012-01-01

    The role of the major histocompatibility complex (MHC) in the immune response makes it an attractive candidate gene for associations with disease resistance and susceptibility. This study describes genetic variability in the BoLA-DRB3 in Iranian buffaloes. Heminested PCR-RFLP method was used to identify the frequency of BoLA-DRB3 alleles. The BoLA-DRB3 locus is highly polymorphic in the study herd (12 alleles). Almost 63.50% of the alleles were accounted for by four alleles (BoLA-DRB3.2 ∗48, ∗20, ∗21, and obe) in Iranian buffalo. The DRB3.2 ∗48 allele frequency (24.20%) was higher than the others. The frequencies of the DRB3.2 ∗20 and DRB3.2 ∗21 are 14.52 and 14.00, respectively, and obe and gbb have a new pattern. Significant distinctions have been found between Iranian buffalo and other cattle breed studied. In the Iranian buffaloes studied alleles associated with resistance to various diseases are found.

  15. Distribution of BoLA-DRB3 Allelic Frequencies and Identification of Two New Alleles in Iranian Buffalo Breed

    PubMed Central

    Mosafer, J.; Heydarpour, M.; Manshad, E.; Russell, G.; Sulimova, G. E.

    2012-01-01

    The role of the major histocompatibility complex (MHC) in the immune response makes it an attractive candidate gene for associations with disease resistance and susceptibility. This study describes genetic variability in the BoLA-DRB3 in Iranian buffaloes. Heminested PCR-RFLP method was used to identify the frequency of BoLA-DRB3 alleles. The BoLA-DRB3 locus is highly polymorphic in the study herd (12 alleles). Almost 63.50% of the alleles were accounted for by four alleles (BoLA-DRB3.2 ∗48, ∗20, ∗21, and obe) in Iranian buffalo. The DRB3.2 ∗48 allele frequency (24.20%) was higher than the others. The frequencies of the DRB3.2 ∗20 and DRB3.2 ∗21 are 14.52 and 14.00, respectively, and obe and gbb have a new pattern. Significant distinctions have been found between Iranian buffalo and other cattle breed studied. In the Iranian buffaloes studied alleles associated with resistance to various diseases are found. PMID:22454612

  16. A limit to the divergent allele advantage model supported by variable pathogen recognition across HLA-DRB1 allele lineages.

    PubMed

    Lau, Q; Yasukochi, Y; Satta, Y

    2015-11-01

    Genetic diversity in human leukocyte antigen (HLA) molecules is thought to have arisen from the co-evolution between host and pathogen and maintained by balancing selection. Heterozygote advantage is a common proposed scenario for maintaining high levels of diversity in HLA genes, and extending from this, the divergent allele advantage (DAA) model suggests that individuals with more divergent HLA alleles bind and recognize a wider array of antigens. While the DAA model seems biologically suitable for driving HLA diversity, there is likely an upper threshold to the amount of sequence divergence. We used peptide-binding and pathogen-recognition capacity of DRB1 alleles as a model to further explore the DAA model; within the DRB1 locus, we examined binding predictions based on two distinct phylogenetic groups (denoted group A and B) previously identified based on non-peptide-binding region (PBR) nucleotide sequences. Predictions in this study support that group A allele and group B allele lineages have contrasting binding/recognition capacity, with only the latter supporting the DAA model. Furthermore, computer simulations revealed an inconsistency in the DAA model alone with observed extent of polymorphisms, supporting that the DAA model could only work effectively in combination with other mechanisms. Overall, we support that the mechanisms driving HLA diversity are non-exclusive. By investigating the relationships among HLA alleles, and pathogens recognized, we can provide further insights into the mechanisms on how humans have adapted to infectious diseases over time.

  17. One-electron pseudopotential investigation of the RbAr and FrAr van der Waals systems

    NASA Astrophysics Data System (ADS)

    Dhiflaoui, J.; Berriche, H.

    2012-12-01

    The potential energy curves of the ground state and many excited states of RbAr and FrAr van der Waals systems have been determined using a one-electron pseudopotential approach. The pseudopotential technique is used to replace the effect of the Rb+ and Fr+ cores and the electron-Ar interaction. In addition a core-core interaction is included. This has permitted to reduce the number of active electrons of the RbAr and FrAr systems to only one electron, the valence electron. This has led to use very large basis sets for Rb, Fr and Ar atoms. In this context, the potential energy curves of the ground and many excited states are performed at the SCF level. The core-core interactions for Rb+Ar and Fr+Ar are included using the CCSD(T) accurate potentials of Hickling et al. [H. Hickling, L. Viehland, D. Shepherd, P. Soldan, E. Lee and T. Wright, Phys. Chem. Chem. Phys. 6 (2004) 4233]. In addition, the spectroscopic constants of these states are derived and compared with the available theoretical works. Such comparison for RbAr has shown a very good agreement for the ground and the first excited states. However, the FrAr system was not studied previously and its spectroscopic constants are presented here for the first time.

  18. A method for intercalibration of U-Th-Pb and 40Ar- 39Ar ages in the Phanerozoic

    NASA Astrophysics Data System (ADS)

    Villeneuve, Mike; Sandeman, Hamish A.; Davis, William J.

    2000-12-01

    The increasing analytical precision of 40Ar- 39Ar geochronological data and its use in studies that combine U-Pb and 40Ar- 39Ar data has necessitated derivation of a means to intercalibrate ages between the two isotopic systems. The primary determinants inhibiting accurate cross calibration are uncertainty in decay constant values and uncertainty in 40Ar∗/ 40K (usually presented as apparent age) for 40Ar- 39Ar standards, notably those derived from the Fish Canyon Tuff. By utilizing a monazite- and biotite bearing Oligocene ash flow tuff (MAC-83) as the primary standard material, precise U-Th-Pb and 40Ar- 39Ar ages can be derived. Because both isotopic systems should reflect closure during the instantaneous eruption event, the 24.21 ± 0.10 Ma 207Pb/ 235U age should match the age resulting from 40Ar- 39Ar biotite analysis. This forced equivalence will partly offset the effects of decay constant uncertainty. Furthermore, by co-irradiating Fish Canyon Tuff sanidine with MAC-83 biotite, the apparent age for Fish Canyon Tuff sanidine is back-calculated to 27.98 ± 0.15 Ma, relative to the MAC-83 207Pb/ 235U age. Hence, intercalibration between the two isotopic systems in a relative sense can be accomplished, allowing for a direct and valid comparison of ages. It is also shown that forcing equivalence of the two isotopic systems minimizes the effect of decay constant uncertainty for samples of Phanerozoic age.

  19. Step heating of 40Ar/ 39Ar standard mineral mixtures: Investigation of a fine-grained bulk sediment provenance tool

    NASA Astrophysics Data System (ADS)

    VanLaningham, Sam; Mark, Darren F.

    2011-05-01

    Quantitative techniques that link sediments to their sources are needed to understand a range of tectonic, climate, and anthropogenic driven Earth surface processes. Many provenance techniques exist for sand-sized material but fewer are available for fine-grained sediment archives. In this respect, bulk 40Ar/ 39Ar ages from silt-sized sediment show potential, but many questions remain about the significance of a bulk sediment 40Ar/ 39Ar age. We interrogate bulk sediment 40Ar/ 39Ar ages by step heating mixtures of well-constrained 40Ar/ 39Ar mineral standards crushed to silt-sized. Silt-sized end member components Alder Creek Sanidine, Taylor Creek Sanidine and Heidelberg Biotite all yield plateau ages within uncertainty of their coarse-grained counterparts. High-resolution step heating (as many as 43 steps) of the mineral mixtures shows that biotite degasses first at lower temperatures compared to the two sanidines that degas generally in concert. Concordant age steps develop at both low and high temperatures and the transition from the isotope signal being dominated by one mineral phase to another is clearly observed. We show that age spectra for the mineral standard mixtures can be modeled and predicted for all mixtures by assuming a (simplistic) Gaussian distributed release of Ar, and by using the degassing maxima, variance, K concentration, and 40Ar/ 39Ar age of each monitor mineral. Thus, bulk sediment 40Ar/ 39Ar ages can be robust indicators of the average cooling/crystallization age of all contributing K-bearing minerals to a depositional center. Furthermore, we discuss the potential to deconvolve individual mineral age populations by model inversion. The application of this bulk sediment provenance technique should not be considered a replacement for single grain analyses. It should be applied to environments that do not provide sand-sized sediment archives (e.g., distal terrigenous sedimentary archives) when information about source changes through time

  20. How the Number of Alleles Influences Gene Expression

    NASA Astrophysics Data System (ADS)

    Hat, Beata; Paszek, Pawel; Kimmel, Marek; Piechor, Kazimierz; Lipniacki, Tomasz

    2007-07-01

    The higher organisms, eukaryotes, are diploid and most of their genes have two homological copies (alleles). However, the number of alleles in a cell is not constant. In the S phase of the cell cycle all the genome is duplicated and then in the G2 phase and mitosis, which together last for several hours, most of the genes have four copies instead of two. Cancer development is, in many cases, associated with a change in allele number. Several genetic diseases are caused by haploinsufficiency: Lack of one of the alleles or its improper functioning. In the paper we consider the stochastic expression of a gene having a variable number of copies. We applied our previously developed method in which the reaction channels are split into slow (connected with change of gene state) and fast (connected with mRNA/protein synthesis/decay), the later being approximated by deterministic reaction rate equations. As a result we represent gene expression as a piecewise deterministic time-continuous Markov process, which is further related with a system of partial differential hyperbolic equations for probability density functions (pdfs) of protein distribution. The stationary pdfs are calculated analytically for haploidal gene or numerically for diploidal and tetraploidal ones. We distinguished nine classes of simultaneous activation of haploid, diploid and tetraploid genes. This allows for analysis of potential consequences of gene duplication or allele loss. We show that when gene activity is autoregulated by a positive feedback, the change in number of gene alleles may have dramatic consequences for its regulation and may not be compensated by the change of efficiency of mRNA synthesis per allele.

  1. Association between ACE D allele and elite short distance swimming.

    PubMed

    Costa, Aldo Matos; Silva, António José; Garrido, Nuno Domingos; Louro, Hugo; de Oliveira, Ricardo Jacó; Breitenfeld, Luiza

    2009-08-01

    The influence of ACE gene on athletic performance has been widely explored, and most of the published data refers to an I/D polymorphism leading to the presence (I allele) or absence (D allele) of a 287-bp sequence in intron 16, determining ACE activity in serum and tissues. A higher I allele frequency has been reported among elite endurance athletes, while the D allele was more frequent among those engaged in more power-orientated sports. However, on competitive swimming, the reproducibility of such associations is controversial. We thus compared the ACE genotype of elite swimmers with that of non-elite swimming cohort and of healthy control subjects. We thus sought an association of the ACE genotype of elite swimmers with their competitive distance. 39 Portuguese Olympic swimming candidates were classified as: short (<200 m) and middle (400-1,500 m) distance swimmers, respectively. A group of 32 non-elite swimmers were studied and classified as well, and a control group (n = 100) was selected from the Portuguese population. Chelex 100 was used for DNA extraction and genotype was determined by PCR-RFLP methods. We found that ACE genotype distribution and allelic frequency differs significantly by event distance only among elite swimmers (P < or = 0.05). Moreover, the allelic frequency of the elite short distance swimmers differed significantly from that of the controls (P = 0.021). No associations were found between middle distance swimmers and controls. Our results seem to support an association between the D allele and elite short distance swimming.

  2. Properties of Ar at extreme compression

    NASA Astrophysics Data System (ADS)

    Greeff, C. W.

    2017-01-01

    I present results from DFT calculations on the equation of state of Ar. These include static lattice, phonon, and first principles molecular dynamics calculations on solid and liquid phases. The calculations extend beyond the metallization transition, which is thought to occur near a density of 9 g/cm3. The QMD room temperature isotherm agrees well with experiment, while the Hugoniot shows some potentially significant differences. Various measures of the Grüneisen parameter, γ, are compared. It is found that in the solid, γ decreases rapidly under compression, and reaches values less than 1/2 at a densities of 12 g/cm3. The liquid Grüneisen parameter is determined from QMD simulations. It is found to have the anomalously low value of 0.2 above melting at ρ = 11 g/cm3. At this density, it is an increasing function of temperature, in contrast to lower densities.

  3. Paleotemperatures at the lunar surfaces from open system behavior of cosmogenic 38Ar and radiogenic 40Ar

    NASA Astrophysics Data System (ADS)

    Shuster, David L.; Cassata, William S.

    2015-04-01

    The simultaneous diffusion of both cosmogenic 38Ar and radiogenic 40Ar from solid phases is controlled by the thermal conditions of rocks while residing near planetary surfaces. Combined observations of 38Ar/37Ar and 40Ar/39Ar ratios during stepwise degassing analyses of neutron-irradiated Apollo samples can distinguish between diffusive loss of Ar due to solar heating of the rocks and that associated with elevated temperatures during or following impact events; the data provide quantitative constraints on the durations and temperatures of each process. From sequentially degassed 38Ar/37Ar ratios can be calculated a spectrum of apparent 38Ar exposure ages versus the cumulative release fraction of 37Ar, which is particularly sensitive to conditions at the lunar surface typically over ∼106-108 year timescales. Due to variable proportions of K- and Ca-bearing glass, plagioclase and pyroxene, with variability in the grain sizes of these phases, each sample will have distinct sensitivity to, and therefore different resolving power on, past near-surface thermal conditions. We present the underlying assumptions, and the analytical and numerical methods used to quantify the Ar diffusion kinetics in multi-phase whole-rock analyses that provide these constraints. For Apollo 15 samples 15016, 15556, and 15596 we find apparent 40Ar/39Ar plateau ages between 3.21 and 3.28 Ga and evidence for diffusive loss of radiogenic 40Ar primarily from K-bearing glass. From 38Ar/37Ar spectra normalized to the apparent Ca/K ratios, we also find evidence of diffusive loss of cosmogenic 38Ar that requires elevated temperatures either during or after surface exposure. Using 39Ar and 37Ar, we construct multiple-phase-multiple diffusion domain (MP-MDD) models to quantify the diffusion kinetics of Ar from a range of macroscopic grain sizes of each phase. While diffusive loss of 40Ar can be explained by brief reheating conditions after crystallization (e.g., during an impact event), we find that

  4. The Metal-Rich Universe

    NASA Astrophysics Data System (ADS)

    Israelian, Garik; Meynet, Georges

    2012-10-01

    Preface; Part I. Abundances in the Galaxy: Field Stars: 1. Metal-rich stars and stellar populations: A brief history and new results; 2. The metal-rich nature of stars with planets; 3. Solar chemical peculiarities; 4. Kinematics of metal-rich stars with and without planets; 5. Elemental abundance trends in the metal-rich thin and thick disks; 6. Metal-rich massive stars - how metal-rich are they?; 7. Hercules stream stars and the metal-rich thick disk; 8. Abundance survey of the galactic thick disk; Part II. Abundances in the Galaxy: Galactic Stars in Clusters, Bulges and Centre: 9. Galactic open clusters with super solar metallicities; 10. Old and very metal-rich open clusters in the BOCCE project; 11. Massive stars vs. nebular abundances in the Orion nebula; 12. Abundance surveys of metal-rich bulge stars; 13. Metal abundances in the galactic center; 14. Light elements in the galactic bulge; 15. Metallicity and ages of selected G-K giants; Part III. Observations - Abundances in Extragalactic Contexts: 16. Stellar abundances of early-type galaxies and galactic spheroids: Evidence for metal-rich stars; 17. Measuring chemical abundances in extragalactic metal-rich HII regions; 18. On the maximum oxygen abundance in metal-rich spiral galaxies; 19. Starbursts and their contribution to metal enrichment; 20. High metallicities at high redshifts; 21. Evolution of dust and elemental abundances in quasar DLAs and GRB afterglows as a function of cosmic time; 22. Dust, metals and diffuse interstellar bands in damped Lyman Alpha systems; 23. Tracing metallicities in the Universe with the James Webb Space Telescope; Part IV. Stellar Populations and Mass Functions: 24. The stellar initial mass function of metal-rich populations; 25. IMF effects on the metallicity and colour evolution of disk galaxies; 26. The metallicity of circumnuclear star forming regions; 27. The stellar population of bulges; 28. The metallicity distribution of the stars in elliptical galaxies; 29. Wolf

  5. Construction of a library of cloned short tandem repeat (STR) alleles as universal templates for allelic ladder preparation.

    PubMed

    Wang, Le; Zhao, Xing-Chun; Ye, Jian; Liu, Jin-Jie; Chen, Ting; Bai, Xue; Zhang, Jian; Ou, Yuan; Hu, Lan; Jiang, Bo-Wei; Wang, Feng

    2014-09-01

    Short tandem repeat (STR) genotyping methods are widely used for human identity testing applications, including forensic DNA analysis. Samples of DNA containing the length-variant STR alleles are typically separated and genotyped by comparison to an allelic ladder. Here, we describe a newly devised library of cloned STR alleles. The library covers alleles X and Y for the sex-determining locus Amelogenin and 259 other alleles for 22 autosomal STR loci (TPOX, D3S1358, FGA, D5S818, CSF1PO, D7S820, D8S1179, TH01, vWA, D13S317, D16S539, D18S51, D21S11, D2S1338, D6S1043, D12S391, Penta E, D19S433, D11S4463, D17S974, D3S4529 and D12ATA63). New primers were designed for all these loci to construct recombinant plasmids so that the library retains core repeat elements of STR as well as 5'- and 3'-flanking sequences of ∼500 base pairs. Since amplicons of commercial STR genotyping kits and systems developed in laboratories are usually distributed from 50 to <500 base pairs, this library could provide universal templates for allelic ladder preparation. We prepared three different sets of allelic ladders for this locus TH01 and an updated version of an allelic ladder for the DNATyper(®)19 multiplex system using these plasmids to confirm the suitability of the library as a good source for allelic ladder preparation. Importantly, the authenticity of each construct was confirmed by bidirectional nucleotide sequencing and we report the repeat structures of the 259 STR alleles. The sequencing results showed all repeat structures we obtained for TPOX, CSF1PO, D7S820, TH01, D16S539, D18S51 and Penta E were the same as reported. However, we identified 102 unreported repeat structures from the other 15 STR loci, supplementing our current knowledge of repeat structures and leading to further understanding of these widely used loci.

  6. Practical reactor production of 41Ar from argon clathrate.

    PubMed

    Mercer, J R; Duke, M J; McQuarrie, S A

    2000-06-01

    The radionuclide 41Ar has many ideal properties as a gas flow tracer. However, the modest cross-section of 40Ar for thermal neutron activation makes preparation of suitable activities of 41Ar technically difficult particularly for low flux reactors. Argon can however be trapped in a molecular complex called a clathrate that can then be irradiated. We prepared argon clathrate and explored its irradiation and stability characteristics. Argon clathrate can be used to provide gigabecquerel quantities of 41Ar even with low power reactors.

  7. 40Ar/39Ar ages from the rhyolite of Alder Creek, California: Age of the Cobb Mountain Normal-Polarity Subchron revisited

    NASA Astrophysics Data System (ADS)

    Turrin, Brent D.; Donnelly-Nolan, Julie M.; Carter Hearn, B., Jr.

    1994-03-01

    New 40Ar/39Ar age determinations on sanidine from the rhyolite of Alder Creek, California, indicate a 1.186 ±0.006 Ma age for the Cobb Mountain Normal-Polarity Subchron. The new age is statistically older (α = 0.05) than the previously reported K-Ar age (1.12 ±0.02 Ma) and agrees with the age suggested by the astronomical polarity time scale. Incomplete extraction of radiogenic 40Ar (40Ar*) from the sanidine is the most likely reason for the disparity between the 40Ar/39Ar and K-Ar ages. Because the Cobb Mountain subchron is a worldwide, short-duration event, and because no widely used interlaboratory 40Ar/39Ar standard younger than 27 Ma exists, we propose that sanidine from the rhyolite of Alder Creek be considered for use as a new Quaternary 40Ar/39Ar mineral standard.

  8. 40Ar/39Ar ages from the rhyolite of Alder Creek, California: age of the Cobb Mountain normal-polarity subchron revisited

    USGS Publications Warehouse

    Turrin, B.D.; Donnelly-Nolan, J. M.; Hearn, B.C.

    1994-01-01

    New 40Ar/39Ar age determinations on sanidine from the rhyolite of Alder Creek, California, indicate a 1.186 ?? 0.006 Ma age for the Cobb Mountain Normal-Polarity Subchron. The hew age is statistically older (?? = 0.05) than the previously reported K-Ar age (1.12 ?? 0.02 Ma) and agrees with the age suggested by the astronomical polarity time scale. Incomplete extraction of radiogenic 40Ar (40Ar*) from the sanidine is the most likely reason for the disparity between the 40Ar/39Ar and K-Ar ages. Because the Cobb Mountain subchron is a worldwide, short-duration event, and because no widely used interlaboratory 40Ar/39Ar standard younger than 27 Ma exists, it is proposed that sanidine from the rhyolite of Alder Creek be considered for use as a new Quaternary 40Ar/39Ar mineral standard. -Authors

  9. (Ar-39)-(Ar-40) dating of mesosiderites - Evidence for major parent body disruption less than 4 Ga ago

    NASA Technical Reports Server (NTRS)

    Bogard, D. D.; Jordan, J. L.; Garrison, D. H.; Mittlefehldt, D.

    1990-01-01

    The (Ar-39) (Ar-40) chronologies were determined for 14 different mesosiderites representing the full range of classification according to recrystallization, and these chronologies were compared with analogous data for other meteorite types and for lunar highland rocks. Results of Ar-Ar chronologies indicate the history of a degassing of Ar due to a major thermal event that occurred less than 3.9 Ga ago; this event is not the metal-silicate mixing event, which is known to have occurred earlier than 4.4 Ga ago. It is suggested that a major collisional disruption-reassembly event less than 3.9 Ga ago took place, leaving the metal-silicate breccias buried under tens of kilometers of rubble, where they cooled slowly through the Ar closure temperatures.

  10. Ar-39 - Ar-40 Evidence for an Approximately 4.26 Ga Impact Heating Event on the LL Parent Body

    NASA Technical Reports Server (NTRS)

    Dixon, E. T.; Bogard, D. D.; Rubin, A. E.

    2003-01-01

    Miller Range 99301 is a type 6, unbrecciated LL chondrite. MIL 99301 is of interest because some compositional and petrographic features suggest it experienced rather high shock grades, whereas other features suggest it is relatively unshocked. Inconsistent shock indicators could be explained if MIL 99301 was shocked but then partly annealed by heat produced by impacts on the parent body. The hypothesis that MIL 99301 experienced high temperature metamorphism (type 6) followed by a later shock event that heated, but did not melt, the constituent feldspar can be evaluated using (39)Ar-(40)Ar chronology. This is because (39)Ar-(40)Ar ages of shocked ordinary chondrites are generally <4.2 Ga, whereas (39)Ar-(40)Ar ages of unshocked meteorites are generally older, and between 4.52 - 4.38 Ga.

  11. STR allele sequence variation: Current knowledge and future issues.

    PubMed

    Gettings, Katherine Butler; Aponte, Rachel A; Vallone, Peter M; Butler, John M

    2015-09-01

    This article reviews what is currently known about short tandem repeat (STR) allelic sequence variation in and around the twenty-four loci most commonly used throughout the world to perform forensic DNA investigations. These STR loci include D1S1656, TPOX, D2S441, D2S1338, D3S1358, FGA, CSF1PO, D5S818, SE33, D6S1043, D7S820, D8S1179, D10S1248, TH01, vWA, D12S391, D13S317, Penta E, D16S539, D18S51, D19S433, D21S11, Penta D, and D22S1045. All known reported variant alleles are compiled along with genomic information available from GenBank, dbSNP, and the 1000 Genomes Project. Supplementary files are included which provide annotated reference sequences for each STR locus, characterize genomic variation around the STR repeat region, and compare alleles present in currently available STR kit allelic ladders. Looking to the future, STR allele nomenclature options are discussed as they relate to next generation sequencing efforts underway.

  12. Estimating Relatedness in the Presence of Null Alleles

    PubMed Central

    Huang, Kang; Ritland, Kermit; Dunn, Derek W.; Qi, Xiaoguang; Guo, Songtao; Li, Baoguo

    2016-01-01

    Studies of genetics and ecology often require estimates of relatedness coefficients based on genetic marker data. However, with the presence of null alleles, an observed genotype can represent one of several possible true genotypes. This results in biased estimates of relatedness. As the numbers of marker loci are often limited, loci with null alleles cannot be abandoned without substantial loss of statistical power. Here, we show how loci with null alleles can be incorporated into six estimators of relatedness (two novel). We evaluate the performance of various estimators before and after correction for null alleles. If the frequency of a null allele is <0.1, some estimators can be used directly without adjustment; if it is >0.5, the potency of estimation is too low and such a locus should be excluded. We make available a software package entitled PolyRelatedness v1.6, which enables researchers to optimize these estimators to best fit a particular data set. PMID:26500259

  13. Assessing allelic dropout and genotype reliability using maximum likelihood.

    PubMed Central

    Miller, Craig R; Joyce, Paul; Waits, Lisette P

    2002-01-01

    A growing number of population genetic studies utilize nuclear DNA microsatellite data from museum specimens and noninvasive sources. Genotyping errors are elevated in these low quantity DNA sources, potentially compromising the power and accuracy of the data. The most conservative method for addressing this problem is effective, but requires extensive replication of individual genotypes. In search of a more efficient method, we developed a maximum-likelihood approach that minimizes errors by estimating genotype reliability and strategically directing replication at loci most likely to harbor errors. The model assumes that false and contaminant alleles can be removed from the dataset and that the allelic dropout rate is even across loci. Simulations demonstrate that the proposed method marks a vast improvement in efficiency while maintaining accuracy. When allelic dropout rates are low (0-30%), the reduction in the number of PCR replicates is typically 40-50%. The model is robust to moderate violations of the even dropout rate assumption. For datasets that contain false and contaminant alleles, a replication strategy is proposed. Our current model addresses only allelic dropout, the most prevalent source of genotyping error. However, the developed likelihood framework can incorporate additional error-generating processes as they become more clearly understood. PMID:11805071

  14. Rare allelic forms of PRDM9 associated with childhood leukemogenesis

    PubMed Central

    Hussin, Julie; Sinnett, Daniel; Casals, Ferran; Idaghdour, Youssef; Bruat, Vanessa; Saillour, Virginie; Healy, Jasmine; Grenier, Jean-Christophe; de Malliard, Thibault; Busche, Stephan; Spinella, Jean-François; Larivière, Mathieu; Gibson, Greg; Andersson, Anna; Holmfeldt, Linda; Ma, Jing; Wei, Lei; Zhang, Jinghui; Andelfinger, Gregor; Downing, James R.; Mullighan, Charles G.; Awadalla, Philip

    2013-01-01

    One of the most rapidly evolving genes in humans, PRDM9, is a key determinant of the distribution of meiotic recombination events. Mutations in this meiotic-specific gene have previously been associated with male infertility in humans and recent studies suggest that PRDM9 may be involved in pathological genomic rearrangements. In studying genomes from families with children affected by B-cell precursor acute lymphoblastic leukemia (B-ALL), we characterized meiotic recombination patterns within a family with two siblings having hyperdiploid childhood B-ALL and observed unusual localization of maternal recombination events. The mother of the family carries a rare PRDM9 allele, potentially explaining the unusual patterns found. From exomes sequenced in 44 additional parents of children affected with B-ALL, we discovered a substantial and significant excess of rare allelic forms of PRDM9. The rare PRDM9 alleles are transmitted to the affected children in half the cases; nonetheless there remains a significant excess of rare alleles among patients relative to controls. We successfully replicated this latter observation in an independent cohort of 50 children with B-ALL, where we found an excess of rare PRDM9 alleles in aneuploid and infant B-ALL patients. PRDM9 variability in humans is thought to influence genomic instability, and these data support a potential role for PRDM9 variation in risk of acquiring aneuploidies or genomic rearrangements associated with childhood leukemogenesis. PMID:23222848

  15. Rare allelic forms of PRDM9 associated with childhood leukemogenesis.

    PubMed

    Hussin, Julie; Sinnett, Daniel; Casals, Ferran; Idaghdour, Youssef; Bruat, Vanessa; Saillour, Virginie; Healy, Jasmine; Grenier, Jean-Christophe; de Malliard, Thibault; Busche, Stephan; Spinella, Jean-François; Larivière, Mathieu; Gibson, Greg; Andersson, Anna; Holmfeldt, Linda; Ma, Jing; Wei, Lei; Zhang, Jinghui; Andelfinger, Gregor; Downing, James R; Mullighan, Charles G; Awadalla, Philip

    2013-03-01

    One of the most rapidly evolving genes in humans, PRDM9, is a key determinant of the distribution of meiotic recombination events. Mutations in this meiotic-specific gene have previously been associated with male infertility in humans and recent studies suggest that PRDM9 may be involved in pathological genomic rearrangements. In studying genomes from families with children affected by B-cell precursor acute lymphoblastic leukemia (B-ALL), we characterized meiotic recombination patterns within a family with two siblings having hyperdiploid childhood B-ALL and observed unusual localization of maternal recombination events. The mother of the family carries a rare PRDM9 allele, potentially explaining the unusual patterns found. From exomes sequenced in 44 additional parents of children affected with B-ALL, we discovered a substantial and significant excess of rare allelic forms of PRDM9. The rare PRDM9 alleles are transmitted to the affected children in half the cases; nonetheless there remains a significant excess of rare alleles among patients relative to controls. We successfully replicated this latter observation in an independent cohort of 50 children with B-ALL, where we found an excess of rare PRDM9 alleles in aneuploid and infant B-ALL patients. PRDM9 variability in humans is thought to influence genomic instability, and these data support a potential role for PRDM9 variation in risk of acquiring aneuploidies or genomic rearrangements associated with childhood leukemogenesis.

  16. A Platform for Interrogating Cancer-Associated p53 Alleles

    PubMed Central

    D’Brot, Alejandro; Kurtz, Paula; Regan, Erin; Jakubowski, Brandon; Abrams, John M

    2016-01-01

    p53 is the most frequently mutated gene in human cancer. Compelling evidence argues that full transformation involves loss of growth suppression encoded by wild-type p53 together with poorly understood oncogenic activity encoded by missense mutations. Furthermore, distinguishing disease alleles from natural polymorphisms is an important clinical challenge. To interrogate the genetic activity of human p53 variants, we leveraged the Drosophila model as an in vivo platform. We engineered strains that replace the fly p53 gene with human alleles, producing a collection of stocks that are, in effect, ‘humanized’ for p53 variants. Like the fly counterpart, human p53 transcriptionally activated a biosensor and induced apoptosis after DNA damage. However, all humanized strains representing common alleles found in cancer patients failed to complement in these assays. Surprisingly, stimulus-dependent activation of hp53 occurred without stabilization, demonstrating that these two processes can be uncoupled. Like its fly counterpart, hp53 formed prominent nuclear foci in germline cells but cancer-associated p53 variants did not. Moreover, these same mutant alleles disrupted hp53 foci and inhibited biosensor activity, suggesting that these properties are functionally linked. Together these findings establish a functional platform for interrogating human p53 alleles and suggest that simple phenotypes could be used to stratify disease variants. PMID:26996664

  17. Identification and characterization of variant alleles at CODIS STR loci.

    PubMed

    Allor, Catherine; Einum, David D; Scarpetta, Marco

    2005-09-01

    Short tandem repeat (STR) profiles from 32,671 individuals generated by the ABI Profiler Plus and Cofiler systems were screened for variant alleles not represented within manufacturer-provided allelic ladders. A total of 85 distinct variants were identified at 12 of the 13 CODIS loci, most of which involve a truncated tetranucleotide repeat unit. Twelve novel alleles, identified at D3S1358, FGA, D18S51, D5S818, D7S820 and TPOX, were confirmed by nucleotide sequence analysis and include both insertions and deletions involving the repeat units themselves as well as DNA flanking the repeat regions. Population genetic data were collected for all variants and frequencies range from 0.0003 (many single observations) to 0.0042 (D7S820 '10.3' in North American Hispanics). In total, the variant alleles identified in this study are carried by 1.6% of the estimated 1 million individuals tested annually in the U.S. for the purposes of parentage resolution. A paternity case involving a recombination event of paternal origin is presented and demonstrates how variant alleles can significantly strengthen the genetic evidence in troublesome cases. In such instances, increased costs and turnaround time associated with additional testing may be eliminated.

  18. Characterization of the ars gene cluster from extremely arsenic-resistant Microbacterium sp. strain A33.

    PubMed

    Achour-Rokbani, Asma; Cordi, Audrey; Poupin, Pascal; Bauda, Pascale; Billard, Patrick

    2010-02-01

    The arsenic resistance gene cluster of Microbacterium sp. A33 contains a novel pair of genes (arsTX) encoding a thioredoxin system that are cotranscribed with an unusual arsRC2 fusion gene, ACR3, and arsC1 in an operon divergent from arsC3. The whole ars gene cluster is required to complement an Escherichia coli ars mutant. ArsRC2 negatively regulates the expression of the pentacistronic operon. ArsC1 and ArsC3 are related to thioredoxin-dependent arsenate reductases; however, ArsC3 lacks the two distal catalytic cysteine residues of this class of enzymes.

  19. Mars’ atmospheric history derived from upper-atmosphere measurements of 38Ar/36Ar

    NASA Astrophysics Data System (ADS)

    Jakosky, B. M.; Slipski, M.; Benna, M.; Mahaffy, P.; Elrod, M.; Yelle, R.; Stone, S.; Alsaeed, N.

    2017-03-01

    The history of Mars’ atmosphere is important for understanding the geological evolution and potential habitability of the planet. We determine the amount of gas lost to space through time using measurements of the upper-atmospheric structure made by the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft. We derive the structure of 38Ar/36Ar between the homopause and exobase altitudes. Fractionation of argon occurs as a result of loss of gas to space by pickup-ion sputtering, which preferentially removes the lighter atom. The measurements require that 66% of the atmospheric argon has been lost to space. Thus, a large fraction of Mars’ atmospheric gas has been lost to space, contributing to the transition in climate from an early, warm, wet environment to today’s cold, dry atmosphere.

  20. Ar-39-Ar-40 ages for the Apollo 15 green and yellow volcanic glasses

    NASA Technical Reports Server (NTRS)

    Spangler, R. R.; Warasila, R.; Delano, J. W.

    1984-01-01

    The laser microprobe was used to extend the Ar-39-Ar-40 method to small, low potassium glassy objects in order to determine the ages of Apollo 15 yellow volcanic, green volcanic group A, and green volcanic group D glasses. The apparent solidification ages for these glasses are 3.62 + or -0.07, 3.41 + or -0.12, and 3.35 + or -.18 aeons, respectively. The ages for group A and d green glasses agree well with previously reported ages for aliquots of 'bulk' green glass. No significant difference in the solidification age was found between the A and D groups. The average exposure ages for the yellow and green glasses from 15426 and 15427 were indistinguishable, with ages between 300 and 275 m.y.

  1. 40Ar/39Ar dates from the West Siberian Basin: Siberian flood basalt province doubled.

    PubMed

    Reichow, Marc K; Saunders, Andrew D; White, Rosalind V; Pringle, Malcolm S; Al'Mukhamedov, Alexander I; Medvedev, Alexander I; Kirda, Nikolay P

    2002-06-07

    Widespread basaltic volcanism occurred in the region of the West Siberian Basin in central Russia during Permo-Triassic times. New 40Ar/39Ar age determinations on plagioclase grains from deep boreholes in the basin reveal that the basalts were erupted 249.4 +/- 0.5 million years ago. This is synchronous with the bulk of the Siberian Traps, erupted further east on the Siberian Platform. The age and geochemical data confirm that the West Siberian Basin basalts are part of the Siberian Traps and at least double the confirmed area of the volcanic province as a whole. The larger area of volcanism strengthens the link between the volcanism and the end-Permian mass extinction.

  2. Interactions of relativistic 36Ar and 40Ar nuclei in hydrogen: Isotopic production cross sections

    NASA Astrophysics Data System (ADS)

    Knott, C. N.; Albergo, S.; Caccia, Z.; Chen, C.-X.; Costa, S.; Crawford, H. J.; Cronqvist, M.; Engelage, J.; Greiner, L.; Guzik, T. G.; Insolia, A.; Lindstrom, P. J.; Mitchell, J. W.; Potenza, R.; Russo, G. V.; Soutoul, A.; Testard, O.; Tull, C. E.; Tuvé, C.; Waddington, C. J.; Webber, W. R.; Wefel, J. P.

    1997-07-01

    The interactions of 36Ar projectile nuclei with energies of 361, 546, and 765 MeV/nucleon and 40Ar nuclei with 352 MeV/nucleon, have been studied in a liquid-hydrogen target as part of a program to study interactions of relevance to the problem of cosmic-ray propagation in the interstellar medium. We have measured the cross sections for the production of isotopic fragments of the projectile nuclei in these interactions. The variations of these cross sections with mass, charge, and energy, are examined for insights into any systematic features of this type of fragmentation reaction that might aid predictions of other, unmeasured cross sections. These cross sections are also compared with the values derived from the most commonly used prediction techniques. It is suggested that these techniques could be improved by taking account of the systematic features identified here.

  3. Acoustic resonance spectroscopy (ARS): ARS300 operations manual, software version 2.01

    SciTech Connect

    1996-07-25

    Acoustic Resonance Spectroscopy (ARS) is a nondestructive evaluation technology developed at the Los Alamos National Laboratory. The ARS technique is a fast, safe, and nonintrusive technique that is particularly useful when a large number of objects need to be tested. Any physical object, whether solid, hollow, or fluid filled, has many modes of vibration. These modes of vibration, commonly referred to as the natural resonant modes or resonant frequencies, are determined by the object`s shape, size, and physical properties, such as elastic moduli, speed of sound, and density. If the object is mechanically excited at frequencies corresponding to its characteristic natural vibrational modes, a resonance effect can be observed when small excitation energies produce large amplitude vibrations in the object. At other excitation frequencies, i.e., vibrational response of the object is minimal.

  4. Differential unroofing within the central metasedimentary Belt of the Grenville Orogen: constraints from 40Ar/39Ar thermochronology

    NASA Astrophysics Data System (ADS)

    Cosca, Michael A.; Essene, Eric J.; Kunk, Michael J.; Sutter, John F.

    1992-04-01

    An 40Ar/39Ar thermochronological investigation of upper greenschist to granulite facies gneiss, amphibolite and marble was conducted in the Central Metasedimentary Belt (CMB), Ontario, to constrain its cooling history. Incremental 40Ar/39Ar release spectra indicate that substantial differential unroofing occurred in the CMB between ˜ 1000 and ˜ 600 Ma. A consistent pattern of significantly older hornblende and phlogopite 40Ar/3Ar cooling ages on the southeast sides of major northeast striking shear zones is interpreted to reflect late displacement due to extensional deformation. Variations in hornblende 40Ar/39Ar age plateaus exceeding 200 Ma occur over distances less than 50 km with major age discontinuities occurring across the Robertson Lake shear zone and the Sharbot Lake mylonite zone which separate the Sharbot Lake terrane from the Elzevir and Frontenac terranes. Extensional displacements of up to 14 km are inferred between the Frontenac and Elzevir terranes of the CMB. No evidence for significant post argon-closure vertical displacement is indicated in the vicinity of the Perth Road mylonite within the Frontenac terrane. Variations of nearly 100 Ma in phlogopite 40Ar/39Ar plateau ages occur in undeformed marble on either side of the Bancroft Shear Zone. Phlogopites from sheared and mylonitized marble within the shear zone yield 40Ar/39Ar diffusional loss profiles, but have older geologically meaningless ages thought to reflect incorporation of excess argon. By ˜ 900 Ma, southeast directed extension was occurring throughout the CMB, possibly initiated along previous zones of compressional shearing. An easterly migration of active zones of extension is inferred, possibly related to an earlier, overall easterly migration of active zones of regional thrusting and easterly migration of an ancient subduction zone. The duration of extensional shearing is not well constrained, but must have ceased before ˜ 600 Ma as required by the deposition of overlying

  5. Differential unroofing within the central metasedimentary Belt of the Grenville Orogen: constraints from 40Ar/39Ar thermochronology

    USGS Publications Warehouse

    Cosca, M.A.; Essene, E.J.; Kunk, M.J.; Sutter, J.F.

    1992-01-01

    An 40Ar/39Ar thermochronological investigation of upper greenschist to granulite facies gneiss, amphibolite and marble was conducted in the Central Metasedimentary Belt (CMB), Ontario, to constrain its cooling history. Incremental 40Ar/39Ar release spectra indicate that substantial differential unroofing occurred in the CMB between ??? 1000 and ??? 600 Ma. A consistent pattern of significantly older hornblende and phlogopite 40Ar/3Ar cooling ages on the southeast sides of major northeast striking shear zones is interpreted to reflect late displacement due to extensional deformation. Variations in hornblende 40Ar/39Ar age plateaus exceeding 200 Ma occur over distances less than 50 km with major age discontinuities occurring across the Robertson Lake shear zone and the Sharbot Lake mylonite zone which separate the Sharbot Lake terrane from the Elzevir and Frontenac terranes. Extensional displacements of up to 14 km are inferred between the Frontenac and Elzevir terranes of the CMB. No evidence for significant post argon-closure vertical displacement is indicated in the vicinity of the Perth Road mylonite within the Frontenac terrane. Variations of nearly 100 Ma in phlogopite 40Ar/39Ar plateau ages occur in undeformed marble on either side of the Bancroft Shear Zone. Phlogopites from sheared and mylonitized marble within the shear zone yield 40Ar/39Ar diffusional loss profiles, but have older geologically meaningless ages thought to reflect incorporation of excess argon. By ??? 900 Ma, southeast directed extension was occurring throughout the CMB, possibly initiated along previous zones of compressional shearing. An easterly migration of active zones of extension is inferred, possibly related to an earlier, overall easterly migration of active zones of regional thrusting and easterly migration of an ancient subduction zone. The duration of extensional shearing is not well constrained, but must have ceased before ??? 600 Ma as required by the deposition of overlying

  6. Genotypic richness predicts phenotypic variation in an endangered clonal plant.

    PubMed

    Evans, Suzanna M; Sinclair, Elizabeth A; Poore, Alistair G B; Bain, Keryn F; Vergés, Adriana

    2016-01-01

    Declines in genetic diversity within a species can affect the stability and functioning of populations. The conservation of genetic diversity is thus a priority, especially for threatened or endangered species. The importance of genetic variation, however, is dependent on the degree to which it translates into phenotypic variation for traits that affect individual performance and ecological processes. This is especially important for predominantly clonal species, as no single clone is likely to maximise all aspects of performance. Here we show that intraspecific genotypic diversity as measured using microsatellites is a strong predictor of phenotypic variation in morphological traits and shoot productivity of the threatened, predominantly clonal seagrass Posidonia australis, on the east coast of Australia. Biomass and surface area variation was most strongly predicted by genotypic richness, while variation in leaf chemistry (phenolics and nitrogen) was unrelated to genotypic richness. Genotypic richness did not predict tissue loss to herbivores or epiphyte load, however we did find that increased herbivore damage was positively correlated with allelic richness. Although there was no clear relationship between higher primary productivity and genotypic richness, variation in shoot productivity within a meadow was significantly greater in more genotypically diverse meadows. The proportion of phenotypic variation explained by environmental conditions varied among different genotypes, and there was generally no variation in phenotypic traits among genotypes present in the same meadows. Our results show that genotypic richness as measured through the use of presumably neutral DNA markers does covary with phenotypic variation in functionally relevant traits such as leaf morphology and shoot productivity. The remarkably long lifespan of individual Posidonia plants suggests that plasticity within genotypes has played an important role in the longevity of the species

  7. Genotypic richness predicts phenotypic variation in an endangered clonal plant

    PubMed Central

    Sinclair, Elizabeth A.; Poore, Alistair G.B.; Bain, Keryn F.; Vergés, Adriana

    2016-01-01

    Declines in genetic diversity within a species can affect the stability and functioning of populations. The conservation of genetic diversity is thus a priority, especially for threatened or endangered species. The importance of genetic variation, however, is dependent on the degree to which it translates into phenotypic variation for traits that affect individual performance and ecological processes. This is especially important for predominantly clonal species, as no single clone is likely to maximise all aspects of performance. Here we show that intraspecific genotypic diversity as measured using microsatellites is a strong predictor of phenotypic variation in morphological traits and shoot productivity of the threatened, predominantly clonal seagrass Posidonia australis, on the east coast of Australia. Biomass and surface area variation was most strongly predicted by genotypic richness, while variation in leaf chemistry (phenolics and nitrogen) was unrelated to genotypic richness. Genotypic richness did not predict tissue loss to herbivores or epiphyte load, however we did find that increased herbivore damage was positively correlated with allelic richness. Although there was no clear relationship between higher primary productivity and genotypic richness, variation in shoot productivity within a meadow was significantly greater in more genotypically diverse meadows. The proportion of phenotypic variation explained by environmental conditions varied among different genotypes, and there was generally no variation in phenotypic traits among genotypes present in the same meadows. Our results show that genotypic richness as measured through the use of presumably neutral DNA markers does covary with phenotypic variation in functionally relevant traits such as leaf morphology and shoot productivity. The remarkably long lifespan of individual Posidonia plants suggests that plasticity within genotypes has played an important role in the longevity of the species

  8. In-situ Ar isotope, 40Ar/39Ar analysis and mineral chemistry of nosean in the phonolite from Olbrück volcano, East Eifel volcanic field, Germany: Implication for the source of excess 40Ar

    NASA Astrophysics Data System (ADS)

    Sudo, Masafumi; Altenberger, Uwe; Günter, Christina

    2014-05-01

    Since the report by Lippolt et al. (1990), hauyne and nosean phenocrysts in certain phonolites from the northwest in the Quaternary East Eifel volcanic field in Germany were known to contain significant amounts of excess 40Ar, thus, show apparent older ages than the other minerals. However, its petrographic meaning have not been well known. Meanwhile, Sumino et al. (2008) has identified the source of the excess 40Ar in the plagioclase phenocrysts from the historic Unzen dacite lava as the melt inclusions in the zones parallely developed to the plagioclase rim by in-situ laser Ar isotope analysis. In order to obtain eruption ages of very young volcanoes as like Quaternary Eifel volcanic field by the K-Ar system, it is quite essential to know about the location of excess 40Ar in volcanic rocks. We have collected phonolites from the Olbrück volcano in East Eifel and investigated its petrography and mineral chemistry and also performed in-situ Ar isotope analyses of unirradiated rock section sample and also in-situ 40Ar/39Ar analysis of neutron irradiated section sample with the UV pulse laser (wavelength 266 nm) and 40Ar/39Ar analytical system of the University of Potsdam. Petrographically, nosean contained fine melt and/or gas inclusions of less than 5 micrometer, which mostly distribute linearly and are relatively enriched in chlorine than the areas without inclusions. Solid inclusions of similar sizes contain CaO and fluorine. In nosean, typically around 5 wt% of sulfur is contained. The 40Ar/39Ar dating was also performed to leucite, sanidine and groundmass in the same section for comparison of those ages with that of nosean. In each analysis, 200 micrometer of beam size was used for making a pit with depth of up to 300 micrometer by laser ablation. As our 40Ar/39Ar analyses were conducted one and half year after the neutron irradiation, thus, short lived 37Ar derived from Ca had decayed very much, we measured Ca and K contents in nosean by SEM-EDS then applied

  9. Refining lunar impact chronology through high spatial resolution (40)Ar/(39)Ar dating of impact melts.

    PubMed

    Mercer, Cameron M; Young, Kelsey E; Weirich, John R; Hodges, Kip V; Jolliff, Bradley L; Wartho, Jo-Anne; van Soest, Matthijs C

    2015-02-01

    Quantitative constraints on the ages of melt-forming impact events on the Moon are based primarily on isotope geochronology of returned samples. However, interpreting the results of such studies can often be difficult because the provenance region of any sample returned from the lunar surface may have experienced multiple impact events over the course of billions of years of bombardment. We illustrate this problem with new laser microprobe (40)Ar/(39)Ar data for two Apollo 17 impact melt breccias. Whereas one sample yields a straightforward result, indicating a single melt-forming event at ca. 3.83 Ga, data from the other sample document multiple impact melt-forming events between ca. 3.81 Ga and at least as young as ca. 3.27 Ga. Notably, published zircon U/Pb data indicate the existence of even older melt products in the same sample. The revelation of multiple impact events through (40)Ar/(39)Ar geochronology is likely not to have been possible using standard incremental heating methods alone, demonstrating the complementarity of the laser microprobe technique. Evidence for 3.83 Ga to 3.81 Ga melt components in these samples reinforces emerging interpretations that Apollo 17 impact breccia samples include a significant component of ejecta from the Imbrium basin impact. Collectively, our results underscore the need to quantitatively resolve the ages of different melt generations from multiple samples to improve our current understanding of the lunar impact record, and to establish the absolute ages of important impact structures encountered during future exploration missions in the inner Solar System.

  10. Ar-40/Ar-39 Age of Hornblende-bearing R Chondrite LAP 04840

    NASA Technical Reports Server (NTRS)

    Righter, K.; Cosca, M.

    2014-01-01

    Chondrites have a complex chronology due to several variables affecting and operating on chondritic parent bodies such as radiogenic heating, pressure and temperature variation with depth, aqueous alteration, and shock or impact heating [1]. Unbrecciated chondrites can record ages from 4.56 to 4.4 Ga that represent cooling in small parent bodies. Some brecciated chondrites exhibit younger ages (<<4 to 4.4 Ga) that may reflect the age of brecciation, disturbance, or shock and impact events (<< 4 Ga). A unique R chondrite was recently found in the LaPaz Icefield of Antarctica - LAP 04840 [2]. This chondrite contains approx.15% hornblende and trace amounts of biotite, making it the first of its kind. Studies have revealed an equigranular texture, mineral equilibria yielding equilibration near 650-700 C and 250-500 bars, hornblende that is dominantly OH-bearing (very little Cl or F), and high D/H ratios [8,9,10]. To help gain a better understanding of the origin of this unique sample, we have measured the Ar-40/Ar-39 age. Age of 4.290 +/- 0.030 Ga is younger than one would expect for a sample that has cooled within a small body [4], and one might instead attribute the age to a younger shock event, On the other hand, there is no evidence for extensive shock in this meteorite (shock stage S2; [3]), so this sample may have been reannealed after the shock event. This age is similar to Ar-Ar ages determined for some other R chondrites

  11. 40Ar/39Ar geochronology and paleomagnetism of Independence volcano, Absaroka volcanic supergroup, Beartooth mountains, Montana

    USGS Publications Warehouse

    Harlan, S.S.; Snee, L.W.; Geissman, J.W.

    1996-01-01

    Independence volcano is a major volcanic complex in the lower part of the Absaroka Volcanic Supergroup (AVS) of Montana and Wyoming. Recently reported Rb-Sr mineral dates from the complex give apparent ages of 91 and 84 Ma, whereas field relationships and the physical and compositional similarity of the rocks with other dated parts of the AVS indicate an Early to Middle Eocene age for eruption and deposition. To resolve the conflict between age assignments based on stratigraphic correlations and Rb-Sr dates, we report new paleomagnetic data and 40Ar/39Ar dates for Independence volcano. Paleomagnetic data for the stock and an and andesite plug that cuts the stock are well grouped, of reverse polarity, and yield a virtual geomagnetic pole that is essentially identical to Late Cretaceous and Tertiary reference poles. The reverse polarity indicates that the magnetization of these rocks is probably younger than the Cretaceous normal superchron, or less than about 83.5 Ma. Hornblende from a volcanic breccia near the base of the volcanic pile gives a 40Ar/39Ar age of 51.57 Ma, whereas biotites from a dacite sill and a granodiorite stock that forms the core of the volcano give dates that range from 49.96 to 48.50 Ma. These dates record the age of eruption and intrusion of these rocks and clearly show that the age of Independence volcano is Early to Middle Eocene, consistent with stratigraphic relations. We suggest that the Rb-Sr mineral dates from the Independence stock and related intrusions are unreliable.

  12. Refining lunar impact chronology through high spatial resolution 40Ar/39Ar dating of impact melts

    PubMed Central

    Mercer, Cameron M.; Young, Kelsey E.; Weirich, John R.; Hodges, Kip V.; Jolliff, Bradley L.; Wartho, Jo-Anne; van Soest, Matthijs C.

    2015-01-01

    Quantitative constraints on the ages of melt-forming impact events on the Moon are based primarily on isotope geochronology of returned samples. However, interpreting the results of such studies can often be difficult because the provenance region of any sample returned from the lunar surface may have experienced multiple impact events over the course of billions of years of bombardment. We illustrate this problem with new laser microprobe 40Ar/39Ar data for two Apollo 17 impact melt breccias. Whereas one sample yields a straightforward result, indicating a single melt-forming event at ca. 3.83 Ga, data from the other sample document multiple impact melt–forming events between ca. 3.81 Ga and at least as young as ca. 3.27 Ga. Notably, published zircon U/Pb data indicate the existence of even older melt products in the same sample. The revelation of multiple impact events through 40Ar/39Ar geochronology is likely not to have been possible using standard incremental heating methods alone, demonstrating the complementarity of the laser microprobe technique. Evidence for 3.83 Ga to 3.81 Ga melt components in these samples reinforces emerging interpretations that Apollo 17 impact breccia samples include a significant component of ejecta from the Imbrium basin impact. Collectively, our results underscore the need to quantitatively resolve the ages of different melt generations from multiple samples to improve our current understanding of the lunar impact record, and to establish the absolute ages of important impact structures encountered during future exploration missions in the inner Solar System. PMID:26601128

  13. The Berkeley Instrumental Neutron Generator (BINGE) for 40Ar/39Ar geochronology

    NASA Astrophysics Data System (ADS)

    Renne, P. R.; Becker, T. A.; Bernstein, L.; Firestone, R. B.; Kirsch, L.; Leung, K. N.; Rogers, A.; Van Bibber, K.; Waltz, C.

    2014-12-01

    The Berkeley Instrumental Neutron Generator (BINGE) facility is the product of a consortium involving the Berkeley Geochronology Center (BGC), the U.C. Berkeley Nuclear Engineering Dept. (UCB/NE), and Lawrence Berkeley (LBNL) and Lawrence Livermore (LLNL) National Labs. BINGE was initially designed (and funded by NSF) for 40Ar/39Ar geochronology. BINGE uses a plasma-based deuteron ion source and a self-loading Ti-surfaced target to induce deuteron-deuterium (DD) fusion via the reaction 2H(d,n)3He, producing 2.45 MeV neutrons. The limited neutron energy spectrum is aimed at reducing recoil effects, interfering nuclear reactions, and unwanted radioactive byproducts, all of which are undesirable consequences of conventional irradiation with 235U fission spectrum neutrons. Minimization of interfering reactions such as 40Ca(n,na)36Ar greatly reduces penalties for over-irradiation, enabling improved signal/background measurement of e.g. 39Ar. BINGE will also be used for a variety of nuclear physics and engineering experiments that require a high flux of monoenergetic neutrons. Neutron energies lower than 2.45 MeV can be obtained via irradiation ports within and external to polyethylene shielding. Initial commissioning produced a neutron flux of 108 n/sec/cm2 at 1 mA source current and 100 kV anode voltage, as expected. When scaled up to the 1 A source current as planned, this indicates that BINGE will achieve the design objective neutron flux of 1011 n/sec/cm2. Further progress towards this goal will be reported. Supported by NSF (grant #EAR-0960138), BGC, UCB/NE, University of California Office of the President, and DOE through LLNL under contract #DE-AC52-07NA27344 and LBNL under contract #DE-AC02-05CH11231.

  14. Geochemistry and 40Ar/39Ar geochronology of the ophiolite in Northern Xinjiang

    NASA Astrophysics Data System (ADS)

    Qinqin, Xu; Jianqing, Ji

    2010-05-01

    As the remnant of ancient oceanic crust, ophiolite is extremely important to reconstruct the framework of ancient ocean and continent. There are several ophiolite belts in Northern Xinjiang, assuming planar distribution, and they are generally related to different faults since Paleozoic in the outcrops. This paper presents a systematic study of geochemistry and geochronology of the gabbro, diabase and basalt of ophiolite collected from different regions in Northern Xinjiang. The intermediate and basic rocks in ophiolite show similar patterns in primitive mantle-normalized REE and trace elements diagrams with MORB and different from IAT, indicating that the ophiolite may be formed in mid-ocean ridge. Their Sr, Nd and Pb isotopic compositions also show that they have mid-ocean ridge environment affinity. Additionally, their Sr, Nd and Pb isotopic ratios are similar respectively, suggesting the same source area, and they also have positive epsilon Nd values(4.40 ~ 8.04), which indicates they likely originate from the depleted mantle. The previous and the author's researches show that the forming time of ophiolite in Northern Xinjiang is early Paleozoic, but 40Ar/39Ar ages of gabbro, diabase and basalt are in the range of 396 ~ 226Ma (mainly from 350 to 250Ma), and no ages of early Paleozoic are gained. Moreover, this time coincides with the timing of late Paleozoic post-collisional plutonism, indicating the ophiolite in Northern Xinjiang was reworked by the late thermal events. The ophiolite widely exposed in Northern Xinjiang have similar characteristics of occurrence, lithologic association and isotopes in spite of diverse special features, which indicates that a relatively uniform and integrated source region has existed in Northern Xinjiang since Paleozoic. It is likely to infer that this source region is related with the long lasting remnant oceanic basin and the related lithosphere since Paleozoic in North Xinjiang. Key Words: Ophiolite, 40Ar/39Ar age

  15. A Deuteron-Deuteron Neutron Generator for 40Ar/39Ar Geochronology

    NASA Astrophysics Data System (ADS)

    Renne, P. R.; Leung, K.; Becker, T.; Cassata, W. S.; Chen, A. X.; Jones, G.

    2010-12-01

    Neutron irradiation of samples for 40Ar/39Ar dating conventionally uses 235U fission reactors whose broad neutron energy spectra engender recoil phenomena, interfering reactions and radiological issues. An alternative source of neutrons with a nearly monoenergetic energy distribution can be obtained via the deuteron-deuteron (D-D) fusion process by which 2 deuterium (D) atoms are fused to create 3He and a neutron with 2.45 MeV energy. Existing neutron generators of this type have produced as much as ~109 n/s, insufficient to provide an alternative to fission reactors. We are building a novel D-D neutron generator aimed at achieving 1012-1013 n/s, featuring a toroidal deuterium plasma ion source that extracts radially inward focused D+ ion beams at 120 kV. The high energy D+ ion beam continuously loads a cylindrical titanium target to form TiD2 at the surface. Subsequent D+ ions then interact with the deuterated titanium to produce the forward biased neutrons that irradiate samples located concentrically inside the cylindrical target. The main limitation on neutron flux is posed by the challenge of cooling the target to prevent outgassing of deuterium from the titanium surface, hence a fluid-cooled Cu-backing is employed. The D-D neutrons to be produced will (1) dramatically reduce the energy (hence displacement) spectrum of recoiling activated 39Ar and 37Ar nuclides, (2) virtually eliminate unwanted interfering reactions on Ca, K, and Cl, and (3) significantly ameliorate radiological concerns due to e.g. collateral activation of Al in sample vessels and samples themselves. Reduction of recoil distances enables fine-grained materials such as clay minerals to be dated more reliably, and the reduction of interfering reactions will reduce the accuracy penalties for over- or under-irradiating samples as well as extending the viability shelf-life of irradiated samples.This project is supported by NSF.

  16. 40Ar/39Ar thermochronology of mesoproterozoic metamorphism in the Colorado Front Range

    USGS Publications Warehouse

    Shaw, C.A.; Snee, L.W.; Selverstone, J.; Reed, J.C.

    1999-01-01

    A low-pressure metamorphic episode in the Colorado Front Range has been identified by the presence of staurolite, andalusite, cordierite, and garnet porphyroblasts overprinting earlier assemblages. The overprinting assemblages and reaction textures are most consistent with porphyroblast growth on a prograde metamorphic path with peak temperatures exceeding ~525??C. Twenty-eight 40Ar/39Ar dates on hornblende, muscovite, biotite, and microcline were used to infer the age and thermal conditions of metamorphism. Muscovite and biotite 40Ar/39Ar ages fall mainly in the interval 1400-1340 Ma, consistent with cooling through the closure temperature interval of micas (~400??-300??C) after about 1400 Ma. In contrast, hornblende apparent ages (T(c)~500??-550??C) between 1600 and 1390 Ma reflect variable retention of radiogenic argon. Forward modeling of argon diffusion shows that the distribution of hornblende and mica ages is consistent with the partial resetting of argon systematics ca. 1400 Ma by a thermal pulse reaching maximum temperatures around 550??C and decaying within <20 m.yr. These temperatures match the conditions inferred from the overprinting assemblage; thus, muscovite and biotite ages are interpreted to date the cooling phase of this metamorphic event. This late metamorphism is broadly coeval with the intrusion of ca. 1400-Ma granitic plutons in the study area and throughout the southwestern United States. However, thermal effects are observed far from pluton margins, suggesting pervasive, regional crustal heating rather than restricted contact metamorphism. Our results suggest that ca. 1400-Ma metamorphism and plutonism are manifestations of a regional thermal episode that both partially melted the lower crust and pervasively metamorphosed middle crustal rocks.

  17. Specific modification of polysulfone with cluster bombardment with assistance of Ar ion irradiation

    NASA Astrophysics Data System (ADS)

    Xu, Guochun; Hibino, Y.; Awazu, K.; Tanihara, M.; Imanishi, Y.

    2000-02-01

    Objective: To develop a rapid method for the modification of polysulfone with ammonium sulfamate with the assistance of Ar ion irradiation with a multi-source cluster deposition apparatus. These surfaces mimicking the structure of heparin, a bioactive molecule, have a high anti-thrombosis property. Experimental Design: Polysulfone film, setting on a turning holder, was irradiated by Ar ions during bombardment with ammonium sulfamate clusters. The Ar ion source serves for the activation of a polymer surface and a cluster ion source supplies ammonium sulfamate molecules to react with the activated surface. After thorough washing with de-ionized sterile water, the modified surfaces were evaluated in terms of the contact angle of water, elemental composition, and binding state on electron spectroscopy for chemical analysis and platelet adhesion with platelet rich plasma. Results: The modification of polysulfone decreased the contact angle of water on surfaces from 82.6 ° down to 34.5 °. Ammonium, amine, sulfate, and thiophene combinations were formed on the modified surfaces. The adhesion numbers of the platelet were decreased to one tenth compared to the original surface. The same process was also applied to other polymers such as polyethylene, polypropylene, and polystyrene and similar outcomes were also observed. Conclusion: The primary studies showed successful modification of polysulfone with ammonium sulfamate with the assistance of Ar ion irradiation. Since the same concept can also be applied to other materials with various substrates, combined with the features of no solvent and no topographic changes, this method might be developed into a promising way for modification of polymeric materials.

  18. Results of 40Ar/39Ar dating of phlogopites from kelyphitic rims around garnet grains (Udachnaya-Vostochnaya kimberlite pipe)

    NASA Astrophysics Data System (ADS)

    Yudin, D. S.; Tomilenko, A. A.; Alifirova, T. A.; Travin, A. V.; Murzintsev, N. G.; Pokhilenko, N. P.

    2016-07-01

    40Ar/39Ar dating of phlogopite from kelyphitic rims around garnet grains from the Udachnaya-Vostochnaya kimberlite pipe in the Sakha (Yakutia) Republic (Russia) revealed that when this mineral has contact with a kimberlite melt its age corresponds (within error limits) to that of the formation of the kimberlite pipe, thus indicating that the method may be used for dating kimberlites and related rocks. In mantle xenoliths, kelyphitic phlogopites rimming garnet grains partially lose radiogenic Ar, which results in a complex age spectrum. Rejuvenation of the K/Ar system in them is determined by the thermal impact of the kimberlite melt on captured rocks.

  19. Identification of two novel human CD1E alleles.

    PubMed

    Mirones, I; Oteo, M; Parra-Cuadrado, J F; Martínez-Naves, E

    2000-08-01

    CD1 is a family of proteins structurally related to major histocompatibility complex (MHC) molecules and specialized in presenting lipids or glycolipids to T cells. In humans, there are five CD1 genes (CD1A to CD1E). It has been shown that, in contrast with classical MHC genes, CD1 loci display a very limited polymorphism. In the present work we describe two novel CD1E alleles found in two healthy Caucasian individuals. One allele differs from the wild-type by a point mutation resulting in a replacement of arginine at position 154 by a tryptophan. In the second allele we found a substitution of the leucine 184 by a proline.

  20. Allele surfing promotes microbial adaptation from standing variation.

    PubMed

    Gralka, Matti; Stiewe, Fabian; Farrell, Fred; Möbius, Wolfram; Waclaw, Bartlomiej; Hallatschek, Oskar

    2016-08-01

    The coupling of ecology and evolution during range expansions enables mutations to establish at expanding range margins and reach high frequencies. This phenomenon, called allele surfing, is thought to have caused revolutions in the gene pool of many species, most evidently in microbial communities. It has remained unclear, however, under which conditions allele surfing promotes or hinders adaptation. Here, using microbial experiments and simulations, we show that, starting with standing adaptive variation, range expansions generate a larger increase in mean fitness than spatially uniform population expansions. The adaptation gain results from 'soft' selective sweeps emerging from surfing beneficial mutations. The rate of these surfing events is shown to sensitively depend on the strength of genetic drift, which varies among strains and environmental conditions. More generally, allele surfing promotes the rate of adaptation per biomass produced, which could help developing biofilms and other resource-limited populations to cope with environmental challenges.

  1. Generation and characterization of an analog-sensitive PERK allele.

    PubMed

    Maas, Nancy L; Singh, Nickpreet; Diehl, J Alan

    2014-08-01

    Restriction of nutrients and oxygen in the tumor microenvironment disrupts ER homeostasis and adaptation to such stress is mediated by the key UPR effector PERK. Given its pro-tumorigenic activity, significant efforts have been made to elucidate the molecular mechanisms that underlie PERK function. Chemical-genetic approaches have recently proven instrumental in pathway mapping and interrogating kinase function. To enable a detailed study of PERK signaling we have generated an analog-sensitive PERK allele that accepts N(6)-alkylated ATP analogs. We find that this allele can be regulated by bulky ATP-competitive inhibitors, confirming the identity of the PERK gatekeeper residue as methionine 886. Furthermore, this analog-sensitive allele can be used to specifically label substrates with thiophosphate both in vitro and in cells. These data highlight the potential for using chemical-genetic techniques to identify novel PERK substrates, thereby providing an expanded view of PERK function and further definition of its signaling networks.

  2. Extensive HLA class I allele promiscuity among viral CTL epitopes

    PubMed Central

    Frahm, Nicole; Yusim, Karina; Suscovich, Todd J.; Adams, Sharon; Sidney, John; Hraber, Peter; Hewitt, Hannah S.; Linde, Caitlyn H.; Kavanagh, Daniel G.; Woodberry, Tonia; Henry, Leah M.; Faircloth, Kellie; Listgarten, Jennifer; Kadie, Carl; Jojic, Nebojsa; Sango, Kaori; Brown, Nancy V.; Pae, Eunice; Zaman, M. Tauheed; Bihl, Florian; Khatri, Ashok; John, Mina; Mallal, Simon; Marincola, Francesco M.; Walker, Bruce D.; Sette, Alessandro; Heckerman, David; Korber, Bette T.; Brander, Christian

    2008-01-01

    Summary Promiscuous binding of T helper epitopes to MHC class II molecules has been well established, but few examples of promiscuous class I restricted epitopes exist. To address the extent of promiscuity of HLA class I peptides, responses to 242 well-defined viral epitopes were tested in 100 subjects regardless of the individuals’ HLA type. Surprisingly, half of all detected responses were seen in the absence of the originally reported restricting HLA class I allele, and only 3% of epitopes were recognized exclusively in the presence of their original allele. Functional assays confirmed the frequent recognition of HLA class I-restricted T cell epitopes on several alternative alleles across HLA class I supertypes and encoded on different class I loci. These data have significant implications for the understanding of MHC class I restricted antigen presentation and vaccine development. PMID:17705138

  3. Distribution of a pseudodeficiency allele among Tay-Sachs carriers

    SciTech Connect

    Tomczak, J.; Grebner, E.E. ); Boogen, C. )

    1993-08-01

    Recently Triggs-Raine et al. (1992) identified a new mutation in the gene coding for the [alpha]-subunit of [beta]-hexosaminidase A (hex A), the enzyme whose deficiency causes Tay-Sachs disease. This mutation, a C[sub 739]-to-T transition in exon 7, results in an altered enzyme that is active (albeit at reduced levels) in cells but that has essentially no activity in serum. This so-called pseudodeficient allele was first detected in compound heterozygotes who also carried a Tay-Sachs disease allele and therefore had no detectable hex A in their serum but who were in good health. Carriers of this apparently benign mutation are generally indistinguishable from carriers of a lethal mutation by means of routine enzyme-based screening tests, because the product of the pseudodeficient allele is not detectable in serum and has decreased activity in cells. This suggests that some individuals who have been classified as Tay-Sachs carriers are actually carriers of the pseudodeficient allele and are not at risk to have a child affected with Tay-Sachs disease. The pseudodeficient allele may also be responsible for some inconclusive diagnoses, where leukocyte values fall below the normal range but are still above the carrier range. The fact that there are now two mutant alleles (the psuedodeficient and the adult) that are indistinguishable from the lethal infantile mutations by means of enzyme assay yet that are phenotypically very different and that together may account for as much as 12% of enzyme-defined carriers on the basis of the data here suggests that DNA analysis should be part of a comprehensive screening program. It will be particularly useful to identify the mutations in couples at risk, before they undergo prenatal diagnosis. DNA analysis will also resolve some inconclusive diagnoses.

  4. A common allele on chromosome 9 associated with coronary heartdisease

    SciTech Connect

    McPherson, Ruth; Pertsemlidis, Alexander; Kavaslar, Nihan; Stewart, Alexandre; Roberts, Robert; Cox, David R.; Hinds, David; Pennachio, Len; Tybjaerg-Hansen, Anne; Folsom, Aaron R.; Boerwinkle,Eric; Hobbs, Helen H.; Cohen, Jonathan C.

    2007-03-01

    Coronary heart disease (CHD) is a major cause of death in Western countries. Here we used genome-wide association scanning to identify a 58 kb interval on chromosome 9 that was consistently associated with CHD in six independent samples. The interval contains no annotated genes and is not associated with established CHD risk factors such as plasma lipoproteins, hypertension or diabetes. Homozygotes for the risk allele comprise 20-25% of Caucasians and have a {approx}30-40% increased risk of CHD. These data indicate that the susceptibility allele acts through a novel mechanism to increase CHD risk in a large fraction of the population.

  5. A Framework for Designing Collaborative Learning Environments Using Mobile AR

    ERIC Educational Resources Information Center

    Cochrane, Thomas; Narayan, Vickel; Antonczak, Laurent

    2016-01-01

    Smartphones provide a powerful platform for augmented reality (AR). Using a smartphone's camera together with the built in GPS, compass, gyroscope, and touch screen enables the real world environment to be overlaid with contextual digital information. The creation of mobile AR environments is relatively simple, with the development of mobile AR…

  6. 75 FR 12163 - Class E Airspace; Mountain View, AR

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-15

    ... Federal Aviation Administration 14 CFR Part 71 Class E Airspace; Mountain View, AR AGENCY: Federal... proposes to amend Class E airspace at Mountain View, AR. Decommissioning of the Wilcox non-directional beacon (NDB) at Mountain View Wilcox Memorial Field Airport has made this action necessary for the...

  7. 75 FR 68416 - Establishment of Class E Airspace; Berryville, AR

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-08

    ... Procedures (SIAP) at Carroll County Airport, Berryville, AR. The FAA is taking this action to enhance the..., creating controlled airspace at Carroll County Airport (75 FR 53876) Docket No. FAA-2010-0690. Interested... accommodate SIAPs at Carroll County Airport, Berryville, AR. This action is necessary for the safety...

  8. 75 FR 12162 - Class E Airspace; Manila, AR

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-15

    ... Federal Aviation Administration 14 CFR Part 71 Class E Airspace; Manila, AR AGENCY: Federal Aviation... Class E airspace at Manila, AR. Decommissioning of the Manila non-directional beacon (NDB) at Manila... amending Class E airspace extending upward from 700 feet above the surface for standard instrument...

  9. 75 FR 12165 - Class E Airspace; Batesville, AR

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-15

    ... TRANSPORTATION Federal Aviation Administration 14 CFR Part 71 Class E Airspace; Batesville, AR AGENCY: Federal... proposes to amend Class E airspace at Batesville, AR. Decommissioning of the Independence County non... Regulations (14 CFR), part 71 by amending Class E airspace extending upward from 700 feet above the...

  10. 40Ar-39Ar age of Northwest Africa 091: More evidence for a link between L chondrites and fossil meteorites

    NASA Astrophysics Data System (ADS)

    Weirich, J. R.; Swindle, T. D.; Isachsen, C. E.

    2012-08-01

    Most 40Ar-39Ar ages of L chondrites record an event at approximately 500 Ma, indicating a large collisional impact at that time. However, there is a spread in ages from 400 to 600 Ma in these meteorites that is greater than the analytical uncertainty. Identification of, and correction for, trapped Ar in a few L chondrites has given an age of 470 ± 6 Ma. This age coincides with Ordivician fossil meteorites that fell to Earth at 467 ± 2 Ma. As these fossil meteorites were originally L chondrites, the apparent conclusion is that a large impact sent a flood of L chondrite material to Earth, while material that remained on the L chondrite parent body was strongly heated and reset. We have reduced 40Ar-39Ar data for Northwest Africa 091 using various techniques that appear in the literature, including identification and subtraction of trapped Ar. These techniques give a range of ages from 455 to 520 Ma, and show the importance of making accurate corrections. By using the most straightforward technique to identify and remove a trapped Ar component (which is neither terrestrial nor primordial), an 40Ar-39Ar age of 475 ± 6 Ma is found for Northwest Africa 091, showing a temporal link to fossil meteorites. In addition, high temperature releases of Northwest Africa 091 contain evidence for a second trapped component, and subtraction of this component indicates a possible second collisional impact at approximately 800 Ma. This earlier age coincides with 40Ar-39Ar ages of some H and L chondrites, and lunar samples.

  11. Effect of surface derived hydrocarbon impurities on Ar plasma properties

    SciTech Connect

    Fox-Lyon, Nick; Oehrlein, Gottlieb S.; Godyak, Valery

    2014-05-15

    The authors report on Langmuir probe measurements that show that hydrocarbon surfaces in contact with Ar plasma cause changes of electron energy distribution functions due to the flux of hydrogen and carbon atoms released by the surfaces. The authors compare the impact on plasma properties of hydrocarbon species gasified from an etching hydrocarbon surface with injection of gaseous hydrocarbons into Ar plasma. They find that both kinds of hydrocarbon injections decrease electron density and slightly increase electron temperatures of low pressure Ar plasma. For low percentages of impurities (∼1% impurity in Ar plasma explored here), surface-derived hydrocarbon species and gas phase injected hydrocarbon molecules cause similar changes of plasma properties for the same number of hydrocarbon molecules injected into Ar with a decrease in electron density of ∼4%.

  12. Custom beamsplitter and AR coatings for interferometry

    NASA Astrophysics Data System (ADS)

    Nyland, K.; Jurgenson, C. A.; Buscher, D. F.; Haniff, C. A.; Young, J. S.; Lewis, J.; Schnell, R.

    2010-07-01

    We report on final fabrication tests for the dielectric coatings for the Magdalena Ridge Observatory Interferometer (MROI) fringe tracking beam combiner. The broadband anti-reflection (1.1 μm to 2.4 μm) and beamsplitter (1.49 μm to 2.31 μm) coatings required have been designed with both optical and mechanical constraints in mind. Not only do these coatings have very low optical losses, but they induce minimal bending of their substrates, thereby giving very low fringe contrast reductions. Performance tests on the deposited coatings at our manufacturers (Optical Surface Technologies, Albuquerque, NM) demonstrate reflection losses of less than 0.5% over the full bandpass of the AR coating, and deviations from the desired 50:50 intensity ratio of the beamsplitter coating of no more than 2%. When combined with the measured wavefront perturbations these results imply that the total fringe visibility losses induced by imperfect coating quality will be no more than 2% for all outputs of the MROI fringe tracking beam combiner.

  13. Hard x ray highlights of AR 5395

    NASA Technical Reports Server (NTRS)

    Schwartz, R. A.; Dennis, Brian R.

    1989-01-01

    Active Region 5395 produced an exceptional series of hard x ray bursts notable for their frequency, intensity, and impulsivity. Over the two weeks from March 6 to 19, 447 hard x ray flares were observed by the Hard X Ray Burst Spectrometer on Solar Maximum Mission (HXRBS/SMM), a rate of approx. 35 per day which exceeded the previous high by more than 50 percent. During one 5 day stretch, more than 250 flares were detected, also a new high. The three largest GOES X-flares were observed by HXRBS and had hard x ray rates over 100,000 s(exp -1) compared with only ten flares above 100,000(exp -1) during the previous nine years of the mission. An ongoing effort for the HXRBS group has been the correlated analysis of hard x ray data with flare data at other wavelengths with the most recent emphasis on those measurements with spatial information. During a series of bursts from AR 5395 at 1644 to 1648 UT on 12 March 1989, simultaneous observations were made by HXRBS and UVSP (Ultra Violet Spectrometer Polarimeter) on SMM, the two-element Owens Valley Radio Observatory (OVRO) interferometric array, and R. Canfield's H-alpha Echelle spectrograph at the National Solar Observatory at Sacramento Peak. The data show strong correlations in the hard x ray, microwave, and UV lightcurves. This event will be the subject of a combined analysis.

  14. AR Sco: A Precessing White Dwarf Synchronar?

    NASA Astrophysics Data System (ADS)

    Katz, J. I.

    2017-02-01

    The emission of the white dwarf–M dwarf binary AR Sco is driven by the rapid synchronization of its white dwarf, rather than by accretion. Synchronization requires a magnetic field ∼100 Gauss at the M dwarf and ∼ {10}8 Gauss at the white dwarf, larger than the fields of most intermediate polars but within the range of fields of known magnetic white dwarfs. The spindown power is dissipated in the atmosphere of the M dwarf, within the near zone of the rotating white dwarf’s field, by magnetic reconnection, accelerating particles that produce the observed synchrotron radiation. The displacement of the optical maximum from conjunction may be explained either by dissipation in a bow wave as the white dwarf’s magnetic field sweeps past the M dwarf or by a misaligned white dwarf rotation axis and oblique magnetic moment. In the latter case the rotation axis precesses with a period of decades, predicting a drift in the orbital phase of the optical maximum. Binaries whose emission is powered by synchronization may be termed synchronars, in analogy to magnetars.

  15. Eruption age of an approximately 100,000-year-old basalt from Ar-40/Ar-39 analysis of partially degassed xenoliths

    NASA Technical Reports Server (NTRS)

    Gillespie, A. R.; Huneke, J. C.; Wasserburg, G. J.

    1984-01-01

    Eleven samples from five partially degassed Mesozoic granitic xenoliths and two late Pleistocene host basalt samples from Sawmill Canyon in Sierra Nevada, California, have been analyzed using stepwise Ar-40/Ar-39 dating techniques. The petrography and analytic techniques are described and the results are presented. Isotopic compositions of Ar released from the xenoliths in several extraction steps at temperatures below about 900 C were colinear in Ar-36/Ar-40 versus Ar-39/Ar-40 diagrams and defined isochrons, giving a mean age of degassing of 119,000 + or - 7000 yr. Ar-40 extracted at higher temperatures included ancient radiogenic Ar-40 that never diffused from the xenoliths during immersion in the magma. This Ar-40 caused an increase in the apparent age for the high-temperature extractions. The high precision of the eruption age determined by this method is comparable to that obtained elsewhere by conventional K/Ar dating of sanidine.

  16. A compilation of K-Ar-ages for southern California

    USGS Publications Warehouse

    Miller, Fred K.; Morton, Douglas M.; Morton, Janet L.; Miller, David M.

    2014-01-01

    The purpose of this report is to make available a large body of conventional K-Ar ages for granitic, volcanic, and metamorphic rocks collected in southern California. Although one interpretive map is included, the report consists primarily of a systematic listing, without discussion or interpretation, of published and unpublished ages that may be of value in future regional and other geologic studies. From 1973 to 1979, 468 rock samples from southern California were collected for conventional K-Ar dating under a regional geologic mapping project of Southern California (predecessor of the Southern California Areal Mapping Project). Most samples were collected and dated between 1974 and 1977. For 61 samples (13 percent of those collected), either they were discarded for varying reasons, or the original collection data were lost. For the remaining samples, 518 conventional K-Ar ages are reported here; coexisting mineral pairs were dated from many samples. Of these K-Ar ages, 225 are previously unpublished, and identified as such in table 1. All K-Ar ages are by conventional K-Ar analysis; no 40Ar/39Ar dating was done. Subsequent to the rock samples collected in the 1970s and reported here, 33 samples were collected and 38 conventional K-Ar ages determined under projects directed at (1) characterization of the Mesozoic and Cenozoic igneous rocks in and on both sides of the Transverse Ranges and (2) clarifying the Mesozoic and Cenozoic tectonics of the eastern Mojave Desert. Although previously published (Beckerman et al., 1982), another eight samples and 11 conventional K-Ar ages are included here, because they augment those completed under the previous two projects.

  17. Sequenced Alleles of the Caenorhabditis Elegans Sex-Determining Gene Her-1 Include a Novel Class of Conditional Promoter Mutations

    PubMed Central

    Perry, M. D.; Trent, C.; Robertson, B.; Chamblin, C.; Wood, W. B.

    1994-01-01

    In the control of Caenorhabditis elegans sex determination, the her-1 gene must normally be activated to allow male development of XO animals and deactivated to allow hermaphrodite development of XX animals. The gene is regulated at the transcriptional level and has two nested male-specific transcripts. The larger of these encodes a small, novel, cysteine-rich protein responsible for masculinizing activity. Of the 32 extant mutant alleles, 30 cause partial or complete loss of masculinizing function (lf), while 2 are gain-of-function (gf) alleles resulting in abnormal masculinization of XX animals. We have identified the DNA sequence changes in each of these 32 alleles. Most affect the protein coding functions of the gene, but six are in the promoter region, including the two gf mutations. These two mutations may define a binding site for negative regulators of her-1. Three of the four remaining promoter mutations are single base changes that cause, surprisingly, temperature-sensitive loss of her-1 function. Such conditional promoter mutations have previously not been found among either prokaryotic or eukaryotic mutants analyzed at the molecular level. PMID:7828816

  18. Ribosomal protein genes are highly enriched among genes with allele-specific expression in the interspecific F1 hybrid catfish.

    PubMed

    Chen, Ailu; Wang, Ruijia; Liu, Shikai; Peatman, Eric; Sun, Luyang; Bao, Lisui; Jiang, Chen; Li, Chao; Li, Yun; Zeng, Qifan; Liu, Zhanjiang

    2016-06-01

    Interspecific hybrids provide a rich source for the analysis of allele-specific expression (ASE). In this work, we analyzed ASE in F1 hybrid catfish using RNA-Seq datasets. While the vast majority of genes were expressed with both alleles, 7-8 % SNPs exhibited significant differences in allele ratios of expression. Of the 66,251 and 177,841 SNPs identified from the datasets of the liver and gill, 5420 (8.2 %) and 13,390 (7.5 %) SNPs were identified as significant ASE-SNPs, respectively. With these SNPs, a total of 1519 and 3075 ASE-genes were identified. Gene Ontology analysis revealed that genes encoding cytoplasmic ribosomal proteins (RP) were highly enriched among ASE genes. Parent-of-origin was determined for 27 and 30 ASE RP genes in the liver and gill, respectively. The results indicated that genes from both channel catfish and blue catfish were involved in ASE. However, each RP gene appeared to be almost exclusively expressed from only one parent, indicating that ribosomes in the hybrid catfish were in the "hybrid" form. Overall representation of RP transcripts among the transcriptome appeared lower in the F1 hybrid catfish than in channel catfish or blue catfish, suggesting that the "hybrid" ribosomes may work more efficiently for translation in the F1 hybrid catfish.

  19. Clonal Ordering of 17p and 5q Allelic Losses in Barrett Dysplasia and Adenocarcinoma

    NASA Astrophysics Data System (ADS)

    Blount, Patricia L.; Meltzer, Stephen J.; Yin, Jing; Huang, Ying; Krasna, Mark J.; Reid, Brian J.

    1993-04-01

    Both 17p and 5q allelic losses appear to be involved in the pathogenesis or progression of many human solid tumors. In colon carcinogenesis, there is strong evidence that the targets of the 17p and 5q allelic losses are TP53, the gene encoding p53, and APC, respectively. It is widely accepted that 5q allelic losses precede 17p allelic losses in the progression to colonic carcinoma. The data, however, supporting this proposed order are largely based on the prevalence of 17p and 5q allelic losses in adenomas and unrelated adenocarcinomas from different patients. We investigated the order in which 17p and 5q allelic losses developed during neoplastic progression in Barrett esophagus by evaluating multiple aneuploid cell populations from the same patient. Using DNA content flow cytometric cell sorting and polymerase chain reaction, 38 aneuploid cell populations from 14 patients with Barrett esophagus who had high grade dysplasia, cancer or both were evaluated for 17p and 5q allelic losses. 17p allelic losses preceded 5q allelic losses in 7 patients, both 17p and 5q allelic losses were present in all aneuploid populations of 4 patients, and only 17p (without 5q) allelic losses were present in the aneuploid populations of 3 patients. In no patient did we find that a 5q allelic loss preceded a 17p allelic loss. Our data suggest that 17p allelic losses typically occur before 5q allelic losses during neoplastic progression in Barrett esophagus.

  20. 40Ar-39Ar Studies of the Shocked L6 Chondrites Allan Hills 78003, Yamato 74445, and Yamato 791384

    NASA Astrophysics Data System (ADS)

    Swindle, T. D.; Isachsen, C. E.; Weirich, J. R.; Kimura, M.

    2011-03-01

    Three heavily shocked L6 chondrites clearly record resetting of their K-Ar systems in the last ~1000 Ma. However, their Ar systematics are complicated enough that it is not obvious whether they were involved in the 475 Ma L-chondrite event.

  1. On Full Disclosure and Transparent Data Flow from 40Ar/39Ar Geochronology Measurements to Data Reduction to Online Repositories

    NASA Astrophysics Data System (ADS)

    Koppers, A. A. P.

    2015-12-01

    Arguably 40Ar/39Ar geochronology is one of the most versatile techniques available to Earth scientists today for the dating of rocks and minerals and determining the rates of geological processes on Earth and in our solar system. Over the last four decades large quantities of high (and lower) quality 40Ar/39Ar data have been produced using many different generations of mass spectrometry instrumentation. This wealth of data is only as useful as its description and availability of metadata allows. Many online data sets or compilations available in the science literature only carry the resulting product, an age and a related uncertainty in millions of years, for example. These data points are far from desirable as these don't allow recalculation against modern-day age standards, decay constants and other parameters essential in 40Ar/39Ar geochronology. Over time these data will become less useful to the research community and eventually these will be put by the wayside. In this presentation I will emphasize the need for full disclosure of all data and metadata involved in 40Ar/39Ar geochronology. I will give examples of how a complex data flow can be kept transparent from sample preparation to measurement to data reduction and eventually the uploading into online data repositories. Without the full disclosure of our data and a transparent data flow, it is evident that we cannot live up to one of the governing doctrines in the sciences, namely reproducibility of our scientific experiments and findings.

  2. Paleomagnetic and 40Ar/39Ar geochronologic data from late Proterozoic mafic dikes and sills, Montana and Wyoming

    USGS Publications Warehouse

    Harlan, Stephen S.; Geissman, John William; Snee, Lawrence W.

    1997-01-01

    Paleomagnetic and 40Ar/39Ar results from mafic dikes and sills in northwestern Wyoming and western Montana yield similar virtual geomagnetic poles and isotopic dates. In combination with paleomagnetic and geochronologic data from elsewhere in the western Cordillera, these data provide evidence for a regional mafic magnetic event at 780 to 770 Ma that affected a large area of western North America.

  3. Tissue-specific patterns of allelically-skewed DNA methylation.

    PubMed

    Marzi, Sarah J; Meaburn, Emma L; Dempster, Emma L; Lunnon, Katie; Paya-Cano, Jose L; Smith, Rebecca G; Volta, Manuela; Troakes, Claire; Schalkwyk, Leonard C; Mill, Jonathan

    2016-01-01

    While DNA methylation is usually thought to be symmetrical across both alleles, there are some notable exceptions. Genomic imprinting and X chromosome inactivation are two well-studied sources of allele-specific methylation (ASM), but recent research has indicated a more complex pattern in which genotypic variation can be associated with allelically-skewed DNA methylation in cis. Given the known heterogeneity of DNA methylation across tissues and cell types we explored inter- and intra-individual variation in ASM across several regions of the human brain and whole blood from multiple individuals. Consistent with previous studies, we find widespread ASM with > 4% of the ∼220,000 loci interrogated showing evidence of allelically-skewed DNA methylation. We identify ASM flanking known imprinted regions, and show that ASM sites are enriched in DNase I hypersensitivity sites and often located in an extended genomic context of intermediate DNA methylation. We also detect examples of genotype-driven ASM, some of which are tissue-specific. These findings contribute to our understanding of the nature of differential DNA methylation across tissues and have important implications for genetic studies of complex disease. As a resource to the community, ASM patterns across each of the tissues studied are available in a searchable online database: http://epigenetics.essex.ac.uk/ASMBrainBlood.

  4. Distribution of forensic marker allelic frequencies in Pernambuco, Northestern Brazil.

    PubMed

    Santos, S M; Souza, C A; Rabelo, K C N; Souza, P R E; Moura, R R; Oliveira, T C; Crovella, S

    2015-04-30

    Pernambuco is one of the 27 federal units of Brazil, ranking seventh in the number of inhabitants. We examined the allele frequencies of 13 short tandem repeat loci (CFS1PO, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D21S11, FGA, TH01, vWA, and TPOX), the minimum recommended by the Federal Bureau of Investigation and commonly used in forensic genetics laboratories in Brazil, in a sample of 609 unrelated individuals from all geographic regions of Pernambuco. The allele frequencies ranged from 5 to 47.2%. No significant differences for any loci analyzed were observed compared with other publications in other various regions of Brazil. Most of the markers observed were in Hardy-Weinberg equilibrium. The occurrence of the allele 47.2 (locus FGA) and alleles 35.1 and 39 (locus D21S11), also described in a single study of the Brazilian population, was observed. The other forensic parameters analyzed (matching probability, power of discrimination, polymorphic information content, paternity exclusion, complement factor I, observed heterozygosity, expected heterozygosity) indicated that the studied markers are very informative for human forensic identification purposes in the Pernambuco population.

  5. Allelism and Molecular Mapping of Soybean Necrotic Root Mutants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mutability of the w4 flower color locus in soybean [Glycine max (L.) Merr.] is conditioned by an allele designated w4-m. Germinal revertants recovered among self-pollinated progeny of mutable plants have been associated with the generation of necrotic root mutations, chlorophyll-deficiency mutation...

  6. A genotype probability index for multiple alleles and haplotypes.

    PubMed

    Percy, A; Kinghorn, B P

    2005-12-01

    We use linear algebra to calculate an index of information content in genotype probabilities which has previously been calculated using trigonometry. The new method can be generalized allowing the index to be calculated for loci with more than two alleles. Applications of this index include its use in genotyping strategies, strategies to manage genetic disorders and in estimation of genotype effects.

  7. Natural allelic variations in highly polyploidy Saccharum complex

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sugarcane (Saccharum spp.) as important sugar and biofuel crop are highly polypoid with complex genomes. A large amount of natural phenotypic variation exists in sugarcane germplasm. Understanding its allelic variance has been challenging but is a critical foundation for discovery of the genomic seq...

  8. Efficient nonmeiotic allele introgression in livestock using custom endonucleases

    PubMed Central

    Tan, Wenfang; Carlson, Daniel F.; Lancto, Cheryl A.; Garbe, John R.; Webster, Dennis A.; Hackett, Perry B.; Fahrenkrug, Scott C.

    2013-01-01

    We have expanded the livestock gene editing toolbox to include transcription activator-like (TAL) effector nuclease (TALEN)- and clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9-stimulated homology-directed repair (HDR) using plasmid, rAAV, and oligonucleotide templates. Toward the genetic dehorning of dairy cattle, we introgressed a bovine POLLED allele into horned bull fibroblasts. Single nucleotide alterations or small indels were introduced into 14 additional genes in pig, goat, and cattle fibroblasts using TALEN mRNA and oligonucleotide transfection with efficiencies of 10–50% in populations. Several of the chosen edits mimic naturally occurring performance-enhancing or disease- resistance alleles, including alteration of single base pairs. Up to 70% of the fibroblast colonies propagated without selection harbored the intended edits, of which more than one-half were homozygous. Edited fibroblasts were used to generate pigs with knockout alleles in the DAZL and APC genes to model infertility and colon cancer. Our methods enable unprecedented meiosis-free intraspecific and interspecific introgression of select alleles in livestock for agricultural and biomedical applications. PMID:24014591

  9. MHC class II DR allelic diversity in bighorn sheep

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We hypothesized that decreased diversity and/or unique polymorphisms in MHC class II alleles of bighorn sheep (BHS, Ovis canadensis) are responsible for lower titer of antibodies against Mannheimia haemolytica leukotoxin, in comparison to domestic sheep (DS, Ovis aries). To test this hypothesis, DRA...

  10. Tissue-specific patterns of allelically-skewed DNA methylation

    PubMed Central

    Marzi, Sarah J.; Meaburn, Emma L.; Dempster, Emma L.; Lunnon, Katie; Paya-Cano, Jose L.; Smith, Rebecca G.; Volta, Manuela; Troakes, Claire; Schalkwyk, Leonard C.; Mill, Jonathan

    2016-01-01

    ABSTRACT While DNA methylation is usually thought to be symmetrical across both alleles, there are some notable exceptions. Genomic imprinting and X chromosome inactivation are two well-studied sources of allele-specific methylation (ASM), but recent research has indicated a more complex pattern in which genotypic variation can be associated with allelically-skewed DNA methylation in cis. Given the known heterogeneity of DNA methylation across tissues and cell types we explored inter- and intra-individual variation in ASM across several regions of the human brain and whole blood from multiple individuals. Consistent with previous studies, we find widespread ASM with > 4% of the ∼220,000 loci interrogated showing evidence of allelically-skewed DNA methylation. We identify ASM flanking known imprinted regions, and show that ASM sites are enriched in DNase I hypersensitivity sites and often located in an extended genomic context of intermediate DNA methylation. We also detect examples of genotype-driven ASM, some of which are tissue-specific. These findings contribute to our understanding of the nature of differential DNA methylation across tissues and have important implications for genetic studies of complex disease. As a resource to the community, ASM patterns across each of the tissues studied are available in a searchable online database: http://epigenetics.essex.ac.uk/ASMBrainBlood. PMID:26786711

  11. Estimating the age of alleles by use of intraallelic variability

    SciTech Connect

    Slatkin, M.; Rannala, B.

    1997-02-01

    A method is presented for estimating the age of an allele by use of its frequency and the extent of variation among different copies. The method uses the joint distribution of the number of copies in a population sample and the coalescence times of the intraallelic gene genealogy conditioned on the number of copies. The linear birth-death process is used to approximate the dynamics of a rare allele in a finite population. A maximum-likelihood estimate of the age of the allele is obtained by Monte Carlo integration over the coalescence times. The method is applied to two alleles at the cystic fibrosis (CFTR) locus, {Delta}F508 and G542X, for which intraallelic variability at three intronic microsatellite loci has been examined. Our results indicate that G542X is somewhat older than {Delta}F508. Although absolute estimates depend on the mutation rates at the microsatellite loci, our results support the hypothesis that {Delta}F508 arose <500 generations ({approx}10,000 years) ago. 32 refs., 4 figs.

  12. Multifragment alleles in DNA fingerprints of the parrot, Amazona ventralis

    USGS Publications Warehouse

    Brock, M.K.; White, B.N.

    1991-01-01

    Human DNA probes that identify variable numbers of tandem repeat loci are being used to generate DNA fingerprints in many animal and plant species. In most species the majority of the sc rable autoradiographic bands of the DNA fingerprint represent alleles from numerous unlinked loci. This study was initiated to use DNA fingerprints to determine the amount of band-sharing among captive Hispaniolan parrots (Amazona ventralis) with known genetic relationships. This would form the data base to examine DNA fingerprints of the closely related and endangered Puerto Rican parrot (A. vittata) and to estimate the degree of inbreeding in the relic population. We found by segregation analysis of the bands scored in the DNA fingerprints of the Hispaniolan parrots that there may be as few as two to five loci identified by the human 33.15 probe. Furthermore, at one locus we identified seven alleles, one of which is represented by as many as 19 cosegregating bands. It is unknown how common multiband alleles might be in natural populations, and their existence will cause problems in the assessment of relatedness by band-sharing analysis. We believe, therefore, that a pedigree analysis should be included in all DNA fingerprinting studies, where possible, in order to estimate the number of loci identified by a minisatellite DNA probe and to examine the nature of their alleles.

  13. Registration of two allelic erect leaf mutants of sorghum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two allelic sorghum [Sorghum bicolor (L.) Moench] erect leaf (erl) mutants were isolated from an Annotated Individually-pedigreed Mutagenized Sorghum (AIMS) mutant library developed at the Plant Stress and Germplasm Development Unit, at Lubbock, Texas. The two mutants, erl1-1 and erl1-2, were isol...

  14. Clinical, Genetic, and Functional Characterization of Four Patients Carrying Partial Loss-of-Function Mutations in the Steroidogenic Acute Regulatory Protein (StAR)

    PubMed Central

    Sahakitrungruang, Taninee; Soccio, Raymond E.; Lang-Muritano, Mariarosaria; Walker, Joanna M.; Achermann, John C.; Miller, Walter L.

    2010-01-01

    Context: Nonclassic congenital lipoid adrenal hyperplasia (lipoid CAH) is a recently recognized disorder caused by mutations in the steroidogenic acute regulatory protein (StAR) that retain partial function. Affected individuals can present with a phenotype of late onset adrenal insufficiency with only mild or minimally disordered sexual development. Objectives: The aim was to delineate the clinical spectrum of StAR mutations and correlate phenotype with StAR activity. Patients: Four patients had nonclassic/atypical lipoid CAH. Adrenal insufficiency was manifested at birth in two patients and at 11 months and 4 yr in the other two. Three were 46,XY with underdeveloped genitalia. Methods: The StAR gene was sequenced, mutations were recreated in expression vectors, and StAR activity was measured as pregnenolone production in COS-1 cells cotransfected with the cholesterol side-chain cleavage system. StAR mutants were expressed as N-62 StAR in bacteria, and purified proteins were tested for activity with isolated steroidogenic mitochondria and for cholesterol-binding capacity. Results: DNA sequencing identified mutations on all alleles. Missense mutations were R188C, G221D, L260P, and F267S; we also tested R192C described by others. The respective activities of R188C, R192C, G221D, L260P, and F267S were 8.0, 39.4, 2.4, 3.1, and 6.1% of wild-type in transfected cells, and 12.8, 54.8, 6.3, 1.8, and 9.5% with isolated mitochondria. Cholesterol binding capacities of R188C, R192C, G221D, L260P, and F267S were 6.7, 55.3, 10.2, 4.6, and 20.9%. These data are correlated to the three-dimensional structure of StAR. Conclusions: There is a broad clinical spectrum of StAR mutations; StAR activities in vitro correlate well with clinical phenotypes. PMID:20444910

  15. The Potential for Measuring Slow Crustal Evolution using Ar-Ar Dating of Large K-feldspar Crystals

    NASA Astrophysics Data System (ADS)

    Kelley, S. P.; Flude, S.

    2012-12-01

    There has been a great deal of debate concerning Ar/Ar age profiles in K-feldspar, even gem quality K-feldspar which should exhibit simple diffusion behaviour. Here we explore their potential for measuring very slow crustal evolution and cratonization. Several different models have been evoked which if correct would challenge our capability to recover long thermal histories from Ar/Ar data. We have measured 40Ar/39Ar ages in gem quality K-feldspar grains from Itrongay Madagascar of 435 [1] - 477 [2] Ma using UV-laserprobe to produce both depth profiles (0-20 microns) and spot traverses (0-1000 microns) to test the mechanisms that might control Ar diffusion in nature. Micron scale UV laser depth profiling was used to determine Ar diffusion adjacent to the natural crystal surface (presumed to have formed as the sample crystallised). UV laser spot dating was used to measure the age variations on length scales of 10s of microns to mm and even cm. The high potassium content and age of the Itrongay sample made it possible to measure natural argon age profiles at high precision and high spatial resolution, to address some of the issues surrounding Ar diffusion. The analysis reveals the presence of very long age gradients in the Itrongay feldspar spanning more than 50Ma - ages as low as 415.7±3.0 Ma were measured at the grain margin and as high as 473.8±2.2 Ma in the core. As previous work on Itrongay feldspar has tended to be carried out on mm-sized fragments without knowledge of the original crystal boundaries, the variation in radiometric ages in the published literature is likely due to these internal age variations. We interpret the age profiles as the combination of diffusion and 40K decay to 40Ar over the full range of spatial scales from micron to centimetre. Thermal models for the thermal history of Itrongay K-feldspar appear to be in agreement with previous thermochronology in the area and hold out the hope for unravelling very long and slow crustal evolution

  16. Toward a high-resolution 40Ar/39Ar geochronology of the Tatun Volcano Group, Taiwan

    NASA Astrophysics Data System (ADS)

    Mesko, G. T.; Song, S.; Chang, S.; Hemming, S. R.; Turrin, B. D.

    2010-12-01

    The Tatun Volcano Group [TVG] consists of five volcanic subgroups of which ~30 edifices have been identified, all in close proximity to the densely populated Taipei Basin to its south (Song et al., 2000, Journal of the Geological Society of China, in Chinese). Evidence of eruptions is in the form of mostly lava flows, with pyroclastic flows, and ash deposition (Tsai et al., 2010, TAO), consistent with vulcanian and plinian eruptions that are only minimally preserved because of the region’s high weathering rate (Belousov et al., 2010, Journal of Volcanology and Geothermal Research). The TVG is made up of calc-alkaline andesite, with few interspersed basaltic lava flows that bear geochemical signatures consistent with subduction volcanism, yet due to tectonic location Teng (1996, Geology) describes it as Ryukyu back-arc basin volcanism, and still others attribute volcanism here to post-collisional collapse of the Taiwan orogen (Wang et al., 1999, Tectonophysics and 2004, Journal of Petrology). Various TVG samples were previously K-Ar dated by Juang and Chen (1989, Bulletin of Central Geological Survey, in Chinese), Tsao (1994, Bulletin of Central Geological Survey, in Chinese), and 40Ar/39Ar whole rock analyses by Lee (1996, masters thesis, National Taiwan University) to suggest volcanism from 2.8-2.5Ma and then from 1.5-.22Ma after which volcanic events ceased. In contrast, radiocarbon dates obtained from charcoal in related sediment by Chen et al. (2010, TAO) and Belousov et al. (2010, Journal of Volcanology Geothermal Research) suggest volcanic activity was present at 20ka and 6ka respectively. The andesite samples are microcrystalline; therefore hand picked aliquots of groundmass from the hand magnetic fraction were subjected to several iterations of sonic rinse in glycine-based soap, then 4N HNO3, then quartz-distilled water in a preparation modified from Nicolaysen et al. (2000, EPSL). Samples were co-irradiated at the USGS facility in Denver using Alder

  17. Evaluation of the IPCC Models (AR4 and AR5) in the Precipitation Simulation in the Northeast of Brazil

    NASA Astrophysics Data System (ADS)

    Alves, José; Vasconcelos Junior, Francisco; Chaves, Rosane; Silva, Emerson; Servain, Jacques; Costa, Alexandre; Sombra, Sérgio; Barbosa, Augusto; Dos Santos, Antonio

    2016-04-01

    With the simulations of the models used in the latest reports from the Intergovernmental Panel on Climate Change (IPCC), comparative studies are necessary between observations and the so-called historical run (C20) and future projections of the AR4 (A2) and AR5 (RCP8.5) experiments, in order to assess whether the AR5 models had a better performance in the representation of physical processes. This article compares the sensitivity of IPCC models (AR4 and AR5) in representing the anuall average and seasonal rainfall variation (summer and autumn) in three regions of the Northeast of Brazil between 1979 and 2000, using the CMAP - CPC (Merged Analysis of Precipitation) data as reference. The projections made by these models for the period 2040-2070 were also analyzed.

  18. Ar-40/Ar-39 and U-Th-Pb dating of separated clasts from the Abee E4 chondrite

    NASA Astrophysics Data System (ADS)

    Bogard, D. D.; Unruh, D. M.; Tatsumoto, M.

    1983-01-01

    Ar-40/Ar-39 and U-Th-Pb are investigated for three clasts from the Abee (E4) enstatite chondrite, yielding Ar-40/Ar-39 plateau ages (and/or maximum ages) of 4.5 Gy, while two of the clasts give average ages of 4.4 Gy. The 4.4-4.5 Gy range does not resolve possible age differences among the clasts. The U-Th-Pb data are consistent with the interpretation that initial clast formation occurred 4.58 Gy ago, and that the clasts have since remained closed systems which have been contaminated with terrestrial Pb. The thermal history of Abee deduced from Ar data seems consistent with that deduced from magnetic data, suggesting that various Abee components experienced separate histories until brecciation no later than 4.4 Gy ago, experiencing no significant subsequent heating.

  19. Unique Thermal Histories from Whole-Rock 40Ar/39Ar Step-heating Data

    NASA Astrophysics Data System (ADS)

    Boehnke, P.; Harrison, M.; Heizler, M. T.; Lovera, O. M.; Warren, P. H.

    2014-12-01

    Step-heating 40Ar/39Ar analysis can reveal spatial distributions of 40Ar* at the micron scale imparted by post- crystallization heating events through complex, multi-diffusion domain models. These efforts have largely focused on single-phase, terrestrial samples with only scant attention paid to multi-phase or extra-terrestrial materials. Generalizing these models to incorporate the multiple activation energies (E) expected from bulk rock samples introduces significant interpretational ambiguity. This is because the thermal crossovers explicit in multi-E cases make the age spectrum a function of the lab heating schedule in thermally disturbed samples. A further difficulty is that unique interpretation of the associated Arrhenius plot is no longer possible and a range of E's can be fitted with equal goodness of fit. In order to address these challenges, we developed a new computational approach that simultaneously inverts the Arrhenius spectra and release pattern using a variant of the Adaptive Particle Swarm Optimization (APSO) algorithm for a square-pulse heating event. Our version uses a Levy Flight to break the swarm out of a local minima rather than randomly modifying a single dimension as in the original APSO. Further we explored issues of Pareto efficiency arising from fitting two fitness functions (i.e., the fit to the age spectra and to the Arrhenius plot) and found an adequate resolution to the classic inability to have a single best fit. By utilizing multiple-E samples, we are able to obtain unique thermal history solutions. Application of these methods to high resolution age spectra of the Jilin chondrite and Apollo 16 samples (North Ray Crater) and found fits of sufficiently high fidelity to constrain the absolute temperature of the thermal episode to better than ±10%.

  20. 40Ar/39Ar constraints on the temporal evolution of Graciosa Island, Azores (Portugal)

    NASA Astrophysics Data System (ADS)

    Larrea, Patricia; Wijbrans, Jan R.; Galé, Carlos; Ubide, Teresa; Lago, Marceliano; França, Zilda; Widom, Elisabeth

    2014-02-01

    Lava flows spanning the eruptive record of Graciosa Island (Azores archipelago) and a gabbro xenolith were dated by 40Ar/39Ar in order to constrain the Pleistocene and Holocene volcanic evolution of the island. The results range from 1.05 Ma to 3.9 ka, whereas prior published K-Ar and 14C ages range from 620 to 2 ka. The formation of the Serra das Fontes shield volcano started at minimum 1.05 Ma, and the magmatic system was active for ca. 600 ky, as suggested by the formation of the gabbro xenolith by magmatic differentiation. Evolved magmas making up the Serra das Fontes-Serra Branca composite volcano were generated at ca. 450 ka. After a period of ca. 110 ky of volcanic inactivity and erosion of volcanic edifices, volcanism was reactivated with the formation of the Vitória Unit NW platform. Later, the development of the Vulcão Central Unit started with the formation of monogenetic cones located to the south of the Serra das Fontes-Serra Branca-Vitória Unit. This volcanism became progressively more evolved and was concentrated in a main eruptive center, forming the Vulcão Central stratovolcano with an age older than 50 ka. The caldera related to this stratovolcano is older than 47 ka and was followed by effusion of basaltic magmas into the caldera, resulting in the formation of a lava lake, which ultimately spilled over the caldera rim at ca. 11 ka. The most recent eruptions on Graciosa formed two small pyroclastic cones within the caldera and the Pico do Timão cone within the Vitória Unit at ca 3.9 ka.

  1. Exact break point of a 50 kb deletion 8 kb centromeric of the HLA-A locus with HLA-A*24:02: the same deletion observed in other A*24 alleles and A*23:01 allele.

    PubMed

    Mitsunaga, Shigeki; Okudaira, Yuko; Kunii, Nanae; Cui, Tailin; Hosomichi, Kazuyoshi; Oka, Akira; Suzuki, Yasuo; Homma, Yasuhiko; Sato, Shinji; Inoue, Ituro; Inoko, Hidetoshi

    2011-08-01

    In a structural aberration analysis of patients with arthritis mutilans, a 50 kb deletion near the HLA-A locus with HLA-A*24:02 allele was detected. It was previously reported that HLA-A*24:02 haplotype harbored a large-scale deletion telomeric of the HLA-A gene in healthy individuals. In order to confirm that the deletion are the same in patients with arthritis mutilans and in healthy individuals, and to identify the break point of this deletion, the boundary sequences across the deletion in A*24:02 was amplified by polymerase chain reaction (PCR) as a 3.7 kb genomic fragment and subjected to nucleotide sequence determination. A comparison of these genomic sequences with those of the non-A*24:02 haplotype revealed that the deleted genomic region spanning 50 kb was flanked by 3.7 kb repetitive element-rich segments homologous to each other on both sides in non-A*24. The nucleotide sequences of the PCR products were identical in patients with arthritis mutilans and in healthy individuals, revealing that the deletion linked to A*24:02 is irrelevant to the onset of arthritis mutilans. The deletion was detected in all other A*24 alleles so far examined but not in other HLA-A alleles, except A*23:01. This finding, along with the phylogenic tree of HLA-A alleles and the presence of the 3.7 kb highly homologous segments at the boundary of the deleted genomic region in A*03 and A*32, may suggest that this HLA-A*24:02-linked deletion was generated by homologous recombination within two 3.7 kb homologous segments situated 50 kb apart in the ancestral A*24 haplotype after divergence from the A*03 and A*32 haplotypes.

  2. High-precision 40Ar/39Ar age for the Jehol Biota

    NASA Astrophysics Data System (ADS)

    Chang, S.; Zhang, H.; Renne, P. R.; Fang, Y.

    2008-12-01

    Abundant fossils of the terrestrial Jehol Biota, including plants, insects, dinosaurs, birds, mammals and freshwater invertebrates, were discovered from the Yixian Formation and the overlying Jiufotang Formation in Inner Mongolia, Hebei Province and Liaoning Province, northeastern China. Because of the exceptional preservation of fossils, the Jehol Biota is one of the most important Mesozoic fossil outcrops and referred to as a "Mesozoic Pompeii". The Jehol Biota has provided a rare opportunity to address questions about the origin of birds, the evolution of feathers and flight, the early diversification of angiosperms and the timing of the radiation of placental mammals. The Tuchengzi Formation, which lies unconformably just below the Yixian Formation and consists mainly of variegated sandstones, is less fossiliferous than the two overlying formations. However, dinosaur tracks, silicified wood and compressed plants are found in this formation. A systematic 40Ar/39Ar dating of the Yixian and the Jiufotang formations was undertaken to provide a framework for understanding the timing and duration of the Jehol Biota and evolutionary events represented within it. Furthermore, determining the absolute age of the Tuchengzi Formation provides information to interpret abundant dinosaur tracks within and provide better age constrains for the beginning of the Jehol Biota. Here we present robust high-precision 40Ar/39Ar data for six tuff samples and two basalt samples collected from the Tuchengzi, the Yixian and the Jiufotang formations near the classic outcrops in western Liaoning, NE China. We obtain an age of 139.5 ± 1.0 Ma for the uppermost Tuchengzi Formation, an age of 129.7 ± 0.5 Ma for a basaltic lava from the bottom of the Yixian Formation and an age of 122.1 ± 0.3 Ma for a tuff from the base of the overlying Jiufotang Formation. Our data indicate that the Yixian Formation was deposited during the Early Cretaceous, the Barremian to early Aptian, within a time span

  3. 40Ar/(39)Ar dating of the Kapthurin Formation, Baringo, Kenya.

    PubMed

    Deino, Alan L; McBrearty, Sally

    2002-01-01

    The(40)Ar/(39)Ar radiometric dating technique has been applied to tuffs and lavas of the Kapthurin Formation in the Tugen Hills, Kenya Rift Valley. Two variants of the(40)Ar/(39)Ar technique, single-crystal total fusion (SCTF) and laser incremental heating (LIH) have been employed to date five marker horizons within the formation: near the base, the Kasurein Basalt at 0.61+/-0.04 Ma; the Pumice Tuff at 0.543+/-0.004 Ma; the Upper Kasurein Basalt at 0.552+/-0.015 Ma; the Grey Tuff at 0.509+/-0.009 Ma; and within the upper part of the formation, the Bedded Tuff at 0.284+/-0.012 Ma. The new, precise radiometric age determination for the Pumice Tuff also provides an age for the widespread Lake Baringo Trachyte, since the Pumice Tuff is the early pyroclastic phase of this voluminous trachyte eruption. These results establish the age of fossil hominids KNM-BK 63-67 and KNM-BK 8518 at approximately 0.510-0.512 Ma, a significant finding given that few Middle Pleistocene hominids are radiometrically dated. The Kapthurin hominids are thus the near contemporaries of those from Bodo, Ethiopia and Tanzania. A flake and core industry from lacustrine sediments in the lower part of the formation is constrained by new dates of 0.55-0.52 Ma, a period during which the Acheulian industry, characterized by handaxes, is known throughout East Africa. Points, typical of the Middle Stone Age (MSA), are found in Kapthurin Formation sediments now shown to date to between 0.509+/-0.009 Ma and 0.284+/-0.012 Ma. This date exceeds previous estimates for the age of the MSA elsewhere in East Africa by 49 ka, and establishes the age of Acheulian to MSA transition for the region. Evidence of the use of the Levallois technique for the manufacture of both small flakes and biface preforms, the systematic production of blades, and the use and processing of red ochre also occurs in this interval. The presence of blades and red ochre at this depth is important as blades signify a high degree of technical

  4. A new approach to cosmogenic corrections in 40Ar/39Ar chronometry: Implications for the ages of Martian meteorites

    NASA Astrophysics Data System (ADS)

    Cassata, W. S.; Borg, L. E.

    2016-08-01

    Anomalously old 40Ar/39Ar ages are commonly obtained from Shergottites and are generally attributed to uncertainties regarding the isotopic composition of the trapped component and/or the presence of excess 40Ar. Old ages can also be obtained if inaccurate corrections for cosmogenic 36Ar are applied. Current methods for making the cosmogenic correction require simplifying assumptions regarding the spatial homogeneity of target elements for cosmogenic production and the distribution of cosmogenic nuclides relative to trapped and reactor-derived Ar isotopes. To mitigate uncertainties arising from these assumptions, a new cosmogenic correction approach utilizing the exposure age determined on an un-irradiated aliquot and step-wise production rate estimates that account for spatial variations in Ca and K is described. Data obtained from NWA 4468 and an unofficial pairing of NWA 2975, which yield anomalously old ages when corrected for cosmogenic 36Ar using conventional techniques, are used to illustrate the efficacy of this new approach. For these samples, anomalous age determinations are rectified solely by the improved cosmogenic correction technique described herein. Ages of 188 ± 17 and 184 ± 17 Ma are obtained for NWA 4468 and NWA 2975, respectively, both of which are indistinguishable from ages obtained by other radioisotopic systems. For other Shergottites that have multiple trapped components, have experienced diffusive loss of Ar, or contain excess Ar, more accurate cosmogenic corrections may aid in the interpretation of anomalous ages. The trapped 40Ar/36Ar ratios inferred from inverse isochron diagrams obtained from NWA 4468 and NWA 2975 are significantly lower than the Martian atmospheric value, and may represent upper mantle or crustal components.

  5. An Improved Cluster Richness Estimator

    SciTech Connect

    Rozo, Eduardo; Rykoff, Eli S.; Koester, Benjamin P.; McKay, Timothy; Hao, Jiangang; Evrard, August; Wechsler, Risa H.; Hansen, Sarah; Sheldon, Erin; Johnston, David; Becker, Matthew R.; Annis, James T.; Bleem, Lindsey; Scranton, Ryan; /Pittsburgh U.

    2009-08-03

    Minimizing the scatter between cluster mass and accessible observables is an important goal for cluster cosmology. In this work, we introduce a new matched filter richness estimator, and test its performance using the maxBCG cluster catalog. Our new estimator significantly reduces the variance in the L{sub X}-richness relation, from {sigma}{sub lnL{sub X}}{sup 2} = (0.86 {+-} 0.02){sup 2} to {sigma}{sub lnL{sub X}}{sup 2} = (0.69 {+-} 0.02){sup 2}. Relative to the maxBCG richness estimate, it also removes the strong redshift dependence of the richness scaling relations, and is significantly more robust to photometric and redshift errors. These improvements are largely due to our more sophisticated treatment of galaxy color data. We also demonstrate the scatter in the L{sub X}-richness relation depends on the aperture used to estimate cluster richness, and introduce a novel approach for optimizing said aperture which can be easily generalized to other mass tracers.

  6. Characterization of Mechanical, Thermal and Wear Properties of Titanium Rich Metallic Glasses.

    DTIC Science & Technology

    1982-12-20

    I D-Ai23 595 CHRACTERIZATION OF MECHANICAL THERMAL AND NEAR / I PROPERTIES OF TITANIUM RI..(U) NORTHEASTERN UNIY BOSTON INA INST OF CHEMICAL ANALYSIS...Mechanical, Thermal andJun 78 - 15 ar 82 Wear Properties of Titanium Rich Metallic Glasses 6. PERFORMINGORG. REPORT NUMBER 7. AUTHOR(e) G. CONTRACT OR GRANT...b, blockh nmibor) metallic glasses transition metal glasses 2 titanium alloy glasses . /reactive alloys /alloys - properties " ABSTRAc C (emwn sm

  7. ELF5-Mediated AR Activation Regulates Prostate Cancer Progression

    PubMed Central

    Li, Kai; Guo, Yongmin; Yang, Xiong; Zhang, Zhihong; Zhang, Changwen; Xu, Yong

    2017-01-01

    The transcription factor E74-like factor 5 (ELF5) is a potent antioncogene that can prevent epithelial-mesenchymal transition (EMT) and metastasis in prostate cancer (PCa). However, little is known how it suppress the tumor growth and if it can interact with androgen receptor (AR). In this study, we find that the ELF5 is frequently expressed in AR activated PCa cells, where it binds to AR acting as a physiological partner and negatively regulates its transcriptional activity. In addition, the interaction between ELF5 and AR is androgen-dependent. Downregulation of ELF5 by shRNA increases the expression of AR-response genes and the progression of PCa. Moreover, ELF5 is a AR-dependent gene that its expression can be induced by androgen and suppressed by antiandrogen treatment. Notably, forced reduction of ELF5 in LNCaP cells facilitates the binding of AR to ARE in ELF5 gene and enabling its transcription, so that low level ELF5 can turn up its own expression by the negative feedback loop. PMID:28287091

  8. ELF5-Mediated AR Activation Regulates Prostate Cancer Progression.

    PubMed

    Li, Kai; Guo, Yongmin; Yang, Xiong; Zhang, Zhihong; Zhang, Changwen; Xu, Yong

    2017-03-13

    The transcription factor E74-like factor 5 (ELF5) is a potent antioncogene that can prevent epithelial-mesenchymal transition (EMT) and metastasis in prostate cancer (PCa). However, little is known how it suppress the tumor growth and if it can interact with androgen receptor (AR). In this study, we find that the ELF5 is frequently expressed in AR activated PCa cells, where it binds to AR acting as a physiological partner and negatively regulates its transcriptional activity. In addition, the interaction between ELF5 and AR is androgen-dependent. Downregulation of ELF5 by shRNA increases the expression of AR-response genes and the progression of PCa. Moreover, ELF5 is a AR-dependent gene that its expression can be induced by androgen and suppressed by antiandrogen treatment. Notably, forced reduction of ELF5 in LNCaP cells facilitates the binding of AR to ARE in ELF5 gene and enabling its transcription, so that low level ELF5 can turn up its own expression by the negative feedback loop.

  9. ARS-12G inertial angular vibration sensor provides nanoradian measurement

    NASA Astrophysics Data System (ADS)

    Laughlin, Darren R.; Smith, Dennis

    2001-08-01

    Applied Technology Associates' ARS-12 is the most sensitive inertial angular vibration sensor available in the market today. The sensing mechanism is based on magnetohydrodynamic (MHD) principles. This sensor has a bandwidth from 1-1000 Hz and a noise-equivalent angle of less than 35 nanoradians from 2-1000 Hz. The ARS-12 can measure inertial angular motions of less than 10 nanoradians at discrete frequencies. Their solid state design makes these sensors smaller and more rugged than any previous angular vibration sensor. In addition, the ARS-12 is essentially impervious to linear acceleration and angular cross-axis sensitivity is limited to incorrect physical alignment. The ARS-12 has recently undergone several design changes in order to survive the space environment. This new model, the ARS-12G, also has increased reliability and tighter performance specifications. The ARS-12G design, testing, and performance will be reviewed in this paper. Several ARS-12G sensor packages are currently being tested and space-qualified for Boeing(HSC) and Japan's space agency, NASDA.

  10. Spatially Resolved, Correlated Variations in Apparent 40Ar/39Ar Ages and Ca/K Ratios in Apollo 17 Impact Melt Breccia 77135

    NASA Astrophysics Data System (ADS)

    Mercer, C. M.; Hodges, K. V.; Jolliff, B. L.; van Soest, M. C.; Wartho, J.-A.; Weirich, J. R.

    2015-07-01

    Although the Apollo 17 impact melt breccia 77135 has experienced partial Ar loss, we found that the high spatial-resolution afforded by the laser microprobe 40Ar/39Ar method allowed us to avoid materials that preferentially experienced Ar loss.

  11. Molecular modeling of the effects of 40Ar recoil in illite particles on their K-Ar isotope dating

    NASA Astrophysics Data System (ADS)

    Szczerba, Marek; Derkowski, Arkadiusz; Kalinichev, Andrey G.; Środoń, Jan

    2015-06-01

    The radioactive decay of 40K to 40Ar is the basis of isotope age determination of micaceous clay minerals formed during diagenesis. The difference in K-Ar ages between fine and coarse grained illite particles has been interpreted using detrital-authigenic components system, its crystallization history or post-crystallization diffusion. Yet another mechanism should also be considered: natural 40Ar recoil. Whether this recoil mechanism can result in a significant enough loss of 40Ar to provide observable decrease of K-Ar age of the finest illite crystallites at diagenetic temperatures - is the primary objective of this study which is based on molecular dynamics (MD) computer simulations. All the simulations were performed for the same kinetic energy (initial velocity) of the 40Ar atom, but for varying recoil angles that cover the entire range of their possible values. The results show that 40Ar recoil can lead to various deformations of the illite structure, often accompanied by the displacement of OH groups or breaking of the Si-O bonds. Depending on the recoil angle, there are four possible final positions of the 40Ar atom with respect to the 2:1 layer at the end of the simulation: it can remain in the interlayer space or end up in the closest tetrahedral, octahedral or the opposite tetrahedral sheet. No simulation angles were found for which the 40Ar atom after recoil passes completely through the 2:1 layer. The energy barrier for 40Ar passing through the hexagonal cavity from the tetrahedral sheet into the interlayer was calculated to be 17 kcal/mol. This reaction is strongly exothermic, therefore there is almost no possibility for 40Ar to remain in the tetrahedral sheet of the 2:1 layer over geological time periods. It will either leave the crystal, if close enough to the edge, or return to the interlayer space. On the other hand, if 40Ar ends up in the octahedral sheet after recoil, a substantially higher energy barrier of 55 kcal/mol prevents it from leaving

  12. Metabolic Pathways of the Camptothecin Analog AR-67

    PubMed Central

    Horn, Jamie; Milewska, Marta; Arnold, Susanne M.

    2011-01-01

    7-tert-Butyldimethylsilyl-10-hydroxycamptothecin (AR-67; also known as DB-67) is a novel lipophilic camptothecin analog in early-phase anticancer clinical trials. In support of these studies, we evaluated the metabolism of AR-67 in vitro and identified potential metabolites in patient samples. The lactone form of AR-67 was found to be preferentially metabolized over AR-67 carboxylate in human microsomes. Subsequently, the lactone form was tested as a substrate in a panel of CYP450 and UDP-glucuronosyltransferase (UGT) enzymes known to metabolize the majority of clinically approved molecules. AR-67 was metabolized by CYP3A5, CYP3A4, CYP1A1, and CYP1A2, in order of activity. Extrahepatic UGT1A8 and UGT1A7 possessed at least 6-fold higher metabolizing activity than UGT1A1 and other UGT enzymes tested. CYP1A1 and UGT1A7 displayed Michaelis-Menten kinetics, whereas CYP3A4, CYP3A5, and UGT1A8 displayed kinetics consistent with substrate inhibition. Chromatographic analysis of representative patient plasma and urine samples demonstrated the presence of AR-67 glucuronides and oxidized products in the urine but only in very minimal amounts. We conclude that limited in vivo metabolism of AR-67 by UGT1A1 may partly explain the absence of AR-67 glucuronides in plasma and hypothesize that UGT1A8- and CYP3A-mediated biotransformation within the gastrointestinal epithelium may provide protective mechanisms against AR-67 gastrointestinal toxicity. PMID:21189330

  13. KIR2DL2/2DL3-E(35) alleles are functionally stronger than -Q(35) alleles.

    PubMed

    Bari, Rafijul; Thapa, Rajoo; Bao, Ju; Li, Ying; Zheng, Jie; Leung, Wing

    2016-03-31

    KIR2DL2 and KIR2DL3 segregate as alleles of a single locus in the centromeric motif of the killer cell immunoglobulin-like receptor (KIR) gene family. Although KIR2DL2/L3 polymorphism is known to be associated with many human diseases and is an important factor for donor selection in allogeneic hematopoietic stem cell transplantation, the molecular determinant of functional diversity among various alleles is unclear. In this study we found that KIR2DL2/L3 with glutamic acid at position 35 (E(35)) are functionally stronger than those with glutamine at the same position (Q(35)). Cytotoxicity assay showed that NK cells from HLA-C1 positive donors with KIR2DL2/L3-E(35) could kill more target cells lacking their ligands than NK cells with the weaker -Q(35) alleles, indicating better licensing of KIR2DL2/L3(+) NK cells with the stronger alleles. Molecular modeling analysis reveals that the glutamic acid, which is negatively charged, interacts with positively charged histidine located at position 55, thereby stabilizing KIR2DL2/L3 dimer and reducing entropy loss when KIR2DL2/3 binds to HLA-C ligand. The results of this study will be important for future studies of KIR2DL2/L3-associated diseases as well as for donor selection in allogeneic stem cell transplantation.

  14. KIR2DL2/2DL3-E35 alleles are functionally stronger than -Q35 alleles

    NASA Astrophysics Data System (ADS)

    Bari, Rafijul; Thapa, Rajoo; Bao, Ju; Li, Ying; Zheng, Jie; Leung, Wing

    2016-03-01

    KIR2DL2 and KIR2DL3 segregate as alleles of a single locus in the centromeric motif of the killer cell immunoglobulin-like receptor (KIR) gene family. Although KIR2DL2/L3 polymorphism is known to be associated with many human diseases and is an important factor for donor selection in allogeneic hematopoietic stem cell transplantation, the molecular determinant of functional diversity among various alleles is unclear. In this study we found that KIR2DL2/L3 with glutamic acid at position 35 (E35) are functionally stronger than those with glutamine at the same position (Q35). Cytotoxicity assay showed that NK cells from HLA-C1 positive donors with KIR2DL2/L3-E35 could kill more target cells lacking their ligands than NK cells with the weaker -Q35 alleles, indicating better licensing of KIR2DL2/L3+ NK cells with the stronger alleles. Molecular modeling analysis reveals that the glutamic acid, which is negatively charged, interacts with positively charged histidine located at position 55, thereby stabilizing KIR2DL2/L3 dimer and reducing entropy loss when KIR2DL2/3 binds to HLA-C ligand. The results of this study will be important for future studies of KIR2DL2/L3-associated diseases as well as for donor selection in allogeneic stem cell transplantation.

  15. Allelic divergence and cultivar-specific SSR alleles revealed by capillary electrophoresis using fluorescence-labeled SSR markers in sugarcane

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Though sugarcane cultivars (Saccharum spp. hybrids) are complex aneu-polyploid hybrids, genetic evaluation and tracking of clone- or cultivar-specific alleles become possible due to capillary electrophoregrams (CE) using fluorescence-labeled SSR primer pairs. Twenty-four sugarcane cultivars, 12 each...

  16. Allelic variation at the vernalization and photoperiod sensitivity loci in Chinese winter wheat cultivars (Triticum aestivum L.).

    PubMed

    Zhang, Xiangfen; Gao, Manxia; Wang, Shasha; Chen, Feng; Cui, Dangqun

    2015-01-01

    A total of 205 wheat cultivars from the Yellow and Huai valley of China were used to identify allelic variations of vernalization and photoperiod response genes, as well as the copy number variations (CNVs) of Ppd-B1 and Vrn-A1 genes. A novel Vrn-D1 allele with 174-bp insertion in the promoter region of the recessive allele vrn-D1 was discovered in three Chinese wheat cultivars and designated as Vrn-D1c. Quantitative real-time polymerase chain reaction showed that cultivars with the Vrn-D1c allele exhibited significantly higher expression of the Vrn-D1 gene than that in cultivars with the recessive allele vrn-D1, indicating that the 174-bp insertion of Vrn-D1c contributed to the increase in Vrn-D1 gene expression and caused early heading and flowering. The five new cis-elements (Box II-like, 3-AF1 binding site, TC-rich repeats, Box-W1 and CAT-box) in the 174-bp insertion possibly promoted the basal activity level of Vrn-D1 gene. Two new polymorphism combinations of photoperiod genes were identified and designated as Ppd-D1_Hapl-IX and Ppd-D1_Hapl-X. Association of the CNV of Ppd-B1 gene with the heading and flowering days showed that the cultivars with Ppd-B1_Hapl-VI demonstrated the earliest heading and flowering times, and those with Ppd-B1_Hapl-IV presented the latest heading and flowering times in three cropping seasons. Distribution of the vernalization and photoperiod response genes indicated that all recessive alleles at the four vernalization response loci, Ppd-B1_Hapl-I at Ppd-B1 locus, and Ppd-D1_Hapl-I at the Ppd-D1 locus were predominant in Chinese winter wheat cultivars. This study can provide useful information for wheat breeding programs to screen wheat cultivars with relatively superior adaptability and maturity.

  17. Allelic variation at the vernalization and photoperiod sensitivity loci in Chinese winter wheat cultivars (Triticum aestivum L.)

    PubMed Central

    Zhang, Xiangfen; Gao, Manxia; Wang, Shasha; Chen, Feng; Cui, Dangqun

    2015-01-01

    A total of 205 wheat cultivars from the Yellow and Huai valley of China were used to identify allelic variations of vernalization and photoperiod response genes, as well as the copy number variations (CNVs) of Ppd-B1 and Vrn-A1 genes. A novel Vrn-D1 allele with 174-bp insertion in the promoter region of the recessive allele vrn-D1 was discovered in three Chinese wheat cultivars and designated as Vrn-D1c. Quantitative real-time polymerase chain reaction showed that cultivars with the Vrn-D1c allele exhibited significantly higher expression of the Vrn-D1 gene than that in cultivars with the recessive allele vrn-D1, indicating that the 174-bp insertion of Vrn-D1c contributed to the increase in Vrn-D1 gene expression and caused early heading and flowering. The five new cis-elements (Box II-like, 3-AF1 binding site, TC-rich repeats, Box-W1 and CAT-box) in the 174-bp insertion possibly promoted the basal activity level of Vrn-D1 gene. Two new polymorphism combinations of photoperiod genes were identified and designated as Ppd-D1_Hapl-IX and Ppd-D1_Hapl-X. Association of the CNV of Ppd-B1 gene with the heading and flowering days showed that the cultivars with Ppd-B1_Hapl-VI demonstrated the earliest heading and flowering times, and those with Ppd-B1_Hapl-IV presented the latest heading and flowering times in three cropping seasons. Distribution of the vernalization and photoperiod response genes indicated that all recessive alleles at the four vernalization response loci, Ppd-B1_Hapl-I at Ppd-B1 locus, and Ppd-D1_Hapl-I at the Ppd-D1 locus were predominant in Chinese winter wheat cultivars. This study can provide useful information for wheat breeding programs to screen wheat cultivars with relatively superior adaptability and maturity. PMID:26191066

  18. Cooling and inferred uplift/erosion history of the Grenville Orogen, Ontario: Constraints from 40Ar/39Ar thermochronology

    NASA Astrophysics Data System (ADS)

    Cosca, Michael A.; Sutter, John F.; Essene, Eric J.

    1991-10-01

    Stepwise 40Ar/39Ar degassing experiments of 57 mineral separates of hornblende, muscovite, biotite, and perthitic microcline have been used in conjunction with petrologic observations to place regional constraints on the postmetamorphic cooling and the inferred uplift and erosion history of the Grenville Orogen in Ontario. The 40Ar/39Ar data support an interpretation of slow, nearly uniform cooling (1°-4°C/m.y.) from temperatures of ˜500°C to below ˜150°C. In the Central Gneiss Belt (CGB) hornblendes cooled through Ar closure between 930 and 1025 Ma, whereas in the Central Metasedimentary Belt (CMB) hornblendes record the following range in 40Ar/39Ar cooling ages: 1104 Ma in the Frontenac terrane, 1007-1067 Ma in the Sharbot Lake terrane, 919-1026 Ma in the Elzevir terrane, and 972 Ma in the Central Metasedimentary Belt Boundary Zone. Regional uplift/erosion rates of 0.03-0.14 km/m.y. have been estimated for the Grenville Orogen in Ontario based on the 40Ar/39Ar data, a model retrograde P-T path for rocks of the CGB, and an upper time constraint provided by flat, overlying Cambrian and Ordovician sediments. These erosion rates are consistent with rates estimated for other Proterozoic or Archean granulite terranes but are an order of magnitude slower than active orogens such as the Alps and Himalayas. A regular variation in hornblende 40Ar/39Ar cooling ages is observed in rocks that traverse highly strained often mylonitic shear zones that separate the four major terranes of the CMB. The pattern of 40Ar/39Ar ages is interpreted to reflect late-tectonic extension, consistent with field observations in the Central Metasedimentary Belt Boundary Zone and elsewhere in the CMB. Up to 13 km of vertical displacement is inferred for some rocks in the CMB between the time they cooled below closure to argon diffusion in hornblende (˜500°C) and their exposure at the surface (˜25°C).

  19. SHRIMP U-Pb and 40Ar/39Ar age constraints for relating plutonism and mineralization in the Boulder batholith region, Montana

    USGS Publications Warehouse

    Lund, K.; Aleinikoff, J.N.; Kunk, M.J.; Unruh, D.M.; Zeihen, G.D.; Hodges, W.C.; du Bray, E.A.; O'Neill, J. M.

    2002-01-01

    The composite Boulder batholith, Montana, hosts a variety of mineral deposit types, including important silver-rich polymetallic quartz vein districts in the northern part of the batholith and the giant Butte porphyry copper-molybdenum pre-Main Stage system and crosscutting copper-rich Main Stage vein system in the southern part of the batholith. Previous dating studies have identified ambiguous relationships among igneous and mineralizing events. Mineralizing hydrothermal fluids for these types of deposits and magma for quartz porphyry dikes at Butte have all been considered to be late-stage differentiates of the Boulder batholith. However, previous dating studies indicated that the Boulder batholith plutons cooled from about 78 to 72 Ma, whereas copper-rich Main Stage veins at Butte were dated at about 61 Ma. Recent efforts to date the porphyry copper-molybdenum pre-Main Stage deposits at Butte resulted in conflicting estimates of both 64 and 76 Ma for the mineralizing events. Silver-rich polymetallic quartz vein deposits elsewhere in the batholith have not been dated previously. To resolve this controversy, we used the U.S. Geological Survey, Stanford, SHRIMP RG ion mic??roprobe to date single-age domains within zircons from plutonic rock samples and 40Ar/39Ar geochronology to date white mica, biotite, and K-feldspar from mineral deposits. U-Pb zircon ages are Rader Creek Granodiorite, 80.4 ?? 1.2 Ma; Unionville Granodiorite, 78.2 ?? 0.8 Ma; Pulpit Rock granite, 76.5 ?? 0.8 Ma; Butte Granite, 74.5 ?? 0.9 Ma; altered Steward-type quartz porphyry dike (I-15 roadcut), 66.5 ?? 1.0 Ma; altered Steward-type quartz porphyry dike (Continental pit), 65.7 ?? 0.9 Ma; and quartz monzodiorite of Boulder Baldy (Big Belt Mountains), 66.2 ?? 0.9 Ma. Zircons from Rader Creek Granodiorite and quartz porphyry dike samples contain Archean inheritance. The 40Ar/39Ar ages are muscovite, silver-rich polymetallic quartz vein (Basin district), 74.4 ?? 0.3 Ma; muscovite, silver-rich

  20. Tri-allelic pattern at the TPOX locus: a familial study.

    PubMed

    Picanço, Juliane Bentes; Raimann, Paulo Eduardo; Paskulin, Giorgio Adriano; Alvarez, Luís; Amorim, António; Batista Dos Santos, Sidney Emanuel; Alho, Clarice Sampaio

    2014-02-10

    Alleles at the TPOX STR locus have 6-14 different numbers of a four-nucleotide (AATG) repeat motif arranged in tandem. Although tri-allelic genotypes are generally rare, the TPOX tri-allelic pattern has a higher frequency, varying widely among populations. Despite this, there are few accurate reports to disclose the nature of the TPOX third allele. In this work we present data obtained from 45 individuals belonging to the same pedigree, in which there are cases of tri-allelic TPOX genotypes. The subjects were apparently healthy with a normal biological development. We noticed six tri-allelic cases in this family, and all of them were women. Karyotype analysis showed no occurrence of partial 2p trisomy. All the tri-allelic cases had the genotype 8-10-11, probably due to three copies of the TPOX STR sequence in all cells (Type 2 tri-allelic pattern). Based on previous data we assumed the allele 10 as the TPOX third allele. The pedigree analyses show evidences that the TPOX extra-allele was the allele10, it is placed far from the main TPOX locus, and that there is a potential linkage of the TPOX extra-allele-10 with Xq. This was the first study that included a large pedigree analysis in order to understand the nature TPOX tri-allelic pattern.

  1. Nonfrequent but well-documented, rare and very rare HLA alleles observed in the Croatian population.

    PubMed

    Grubic, Z; Burek Kamenaric, M; Maskalan, M; Stingl Jankovic, K; Zunec, R

    2014-12-01

    The aim of the study was to evaluate the presence of nonfrequent, rare and very rare alleles among Croats and to estimate whether they are associated with specific alleles at other human leukocyte antigen (HLA) loci. This retrospective study included the typing results from the last 10 years; total number of individuals included was approximately 45,000. Among 17 alleles so far observed only once in our population, 6 (A*24:41, B*07:02:28, B*35:03:03, B*39:40N, DRB1*13:23 and DRB1*14:111) belong to very rare alleles, 2 (B*44:16 and DRB1*01:31) belong to rare alleles according to the 'Rare Alleles Detector' tool ( www.allelefrequencies.net), while for the B*35:101:01 allele published data exist only in the IMGT/HLA database. The remaining eight HLA alleles observed only once among Croats are considered as frequent according to the 'Rare Alleles Detector'. Those 17 HLA alleles are not declared as common well defined (CWD) alleles in the CWD allele catalogue 2.0.0. Haplotype analysis of nonfrequent alleles detected in our sample supports the idea that different populations, although similar in some aspects regarding HLA allele and haplotype distribution, still have some unique characteristics. This is the case for A*01:02, B*39:10 and DRB1*13:32 which form haplotypes unreported to date among our subjects.

  2. Deactivation of lipopolysaccharide by Ar and H2 inductively coupled low-pressure plasma

    NASA Astrophysics Data System (ADS)

    Bartis, E. A. J.; Barrett, C.; Chung, T.-Y.; Ning, N.; Chu, J.-W.; Graves, D. B.; Seog, J.; Oehrlein, G. S.

    2014-01-01

    Using an inductively coupled plasma system, we study the effects of direct plasma, plasma-generated high-energy photons in the ultraviolet and vacuum ultraviolet (UV/VUV), and radical treatments on lipopolysaccharide (LPS). LPS is a biomolecule found in the outer membrane of Gram-negative bacteria and a potent stimulator of the immune system composed of polysaccharide and lipid A, which contains six aliphatic chains. LPS film thickness spun on silicon was monitored by ellipsometry while the surface chemistry was characterized before and after treatments by x-ray photoelectron spectroscopy (XPS). Additionally, biological activity was measured using an enzyme-linked immunosorbent assay under (a) a sensitive regime (sub-µM concentrations of LPS) and (b) a bulk regime (above µM concentrations of LPS) after plasma treatments. Direct plasma treatment causes rapid etching and deactivation of LPS in both Ar and H2 feed gases. To examine the effect of UV/VUV photons, a long-pass filter with a cut-off wavelength of 112 nm was placed over the sample. H2 UV/VUV treatment causes material removal and deactivation due to atomic and molecular UV/VUV emission while Ar UV/VUV treatment shows minimal effects as Ar plasma does not emit UV/VUV photons in the transmitted wavelength range explored. Interestingly, radical treatments remove negligible material but cause deactivation. Based on the amphiphilic structure of LPS, we expect a lipid A rich surface layer to form at the air-water interface during sample preparation with polysaccharide layers underneath. XPS shows that H2 plasma treatment under direct and UV/VUV conditions causes oxygen depletion through removal of C-O and O-C = O bonds in the films, which does not occur in Ar treatments. Damage to these groups can remove aliphatic chains that contribute to the pyrogenicity of LPS. Radical treatments from both Ar and H2 plasmas remove aliphatic carbon from the near-surface, demonstrating the important role of neutral species.

  3. Jurassic cooling ages in Paleozoic to early Mesozoic granitoids of northeastern Patagonia: 40Ar/39Ar, 40K-40Ar mica and U-Pb zircon evidence

    NASA Astrophysics Data System (ADS)

    Martínez Dopico, Carmen I.; Tohver, Eric; López de Luchi, Mónica G.; Wemmer, Klaus; Rapalini, Augusto E.; Cawood, Peter A.

    2016-12-01

    U-Pb SHRIMP zircon crystallization ages and Ar-Ar and K-Ar mica cooling ages for basement rocks of the Yaminué and Nahuel Niyeu areas in northeastern Patagonia are presented. Granitoids that cover the time span from Ordovician to Early Triassic constitute the main outcrops of the western sector of the Yaminué block. The southern Yaminué Metaigneous Complex comprises highly deformed Ordovician and Permian granitoids crosscut by undeformed leucogranite dikes (U-Pb SHRIMP zircon age of 254 ± 2 Ma). Mica separates from highly deformed granitoids from the southern sector yielded an Ar-Ar muscovite age of 182 ± 3 Ma and a K-Ar biotite age of 186 ± 2 Ma. Moderately to highly deformed Permian to Early Triassic granitoids made up the northern Yaminué Complex. The Late Permian to Early Triassic (U-Pb SHRIMP zircon age of 252 ± 6 Ma) Cabeza de Vaca Granite of the Yaminué block yielded Jurassic mica K-Ar cooling ages (198 ± 2, 191 ± 1, and 190 ± 2 Ma). At the boundary between the Yaminué and Nahuel Niyeu blocks, K-Ar muscovite ages of 188 ± 3 and 193 ± 5 Ma were calculated for the Flores Granite, whereas the Early Permian Navarrete granodiorite, located in the Nahuel Niyeu block, yielded a K-Ar biotite age of 274 ± 4 Ma. The Jurassic thermal history is not regionally uniform. In the supracrustal exposures of the Nahuel Niyeu block, the Early Permian granitoids of its western sector as well as other Permian plutons and Ordovician leucogranites located further east show no evidence of cooling age reset since mica ages suggest cooling in the wake of crystallization of these intrusive rocks. In contrast, deeper crustal levels are inferred for Permian-Early Triassic granitoids in the Yaminué block since cooling ages for these rocks are of Jurassic age (198-182 Ma). Jurassic resetting is contemporaneous with the massive Lower Jurassic Flores Granite, and the Marifil and Chon Aike volcanic provinces. This intraplate deformational pulse that affected northeastern

  4. Application of periodogram and AR spectral analysis to EEG signals.

    PubMed

    Akin, M; Kiymik, M K

    2000-08-01

    In this study, in order to analyze the EEG signal, the conventional and modern spectral methods were investigated. Interpretation and performance of these methods were detected for clinical applications. For this purpose EEG data obtained from different persons were processed by PC computer using periodogram and AR model algorithms. Periodogram and AR modeling approaches were compared for their resolution and interpretation performance. It was determined that the AR approach is better for the use in clinical and research areas, because of the clear spectra that are obtained by it.

  5. A generic interface element for COMET-AR

    NASA Technical Reports Server (NTRS)

    Mccleary, Susan L.; Aminpour, Mohammad A.

    1995-01-01

    The implementation of an interface element capability within the COMET-AR software system is described. The report is intended for use by both users of currently implemented interface elements and developers of new interface element formulations. Guidance on the use of COMET-AR is given. A glossary is provided as an Appendix to this report for readers unfamiliar with the jargon of COMET-AR. A summary of the currently implemented interface element formulation is presented in Section 7.3 of this report.

  6. 40Ar-39Ar ages of H-chondrite impact melt breccias

    NASA Astrophysics Data System (ADS)

    Swindle, T. D.; Isachsen, C. E.; Weirich, J. R.; Kring, D. A.

    2009-07-01

    40Ar-39Ar analyses of a total of 26 samples from eight shock-darkened impact melt breccias of H-chondrite affinity (Gao-Guenie, LAP 02240, LAP 03922, LAP 031125, LAP 031173, LAP 031308, NWA 2058, and Ourique) are reported. These appear to record impacts ranging in time from 303 ± 56 Ma (Gao-Guenie) to 4360 ± 120 Ma (Ourique) ago. Three record impacts 300-400 Ma ago, while two others record impacts 3900-4000 Ma ago. Combining these with other impact ages from H chondrites in the literature, it appears that H chondrites record impacts in the first 100 Ma of solar system history, during the era of the “lunar cataclysm” and shortly thereafter (3500-4000 Ma ago), one or more impacts ˜300 Ma ago, and perhaps an impact ˜500 Ma ago (near the time of the L chondrite parent body disruption). Records of impacts on the H chondrite parent body are rare or absent between the era of planetary accretion and the “lunar cataclysm” (4400-4050 Ma), during the long stretch between heavy bombardment and recent breakup events (3500-1000 Ma), or at the time of final breakup into meteorite-sized bodies (<50 Ma).

  7. (40)Ar/(39)Ar Age of Hornblende-Bearing R Chondrite LAP 04840

    NASA Technical Reports Server (NTRS)

    Righter, K.; Cosca, M.

    2015-01-01

    Chondrites have a complex chronology due to several variables affecting and operating on chondritic parent bodies such as radiogenic heating, pressure and temperature variation with depth, aqueous alteration, and shock or impact heating. Unbrecciated chondrites can record ages from 4.56 to 4.4 Ga that represent cooling in small parent bodies. Some brecciated chondrites exhibit younger ages (much less than 4 to 4.4 Ga) that may reflect the age of brecciation, disturbance, or shock and impact events (much less than 4 Ga). A unique R chondrite was recently found in the LaPaz Icefield of Antarctica - LAP 04840. This chondrite contains approximately 15% hornblende and trace amounts of biotite, making it the first of its kind. Studies have revealed an equigranular texture, mineral equilibria yielding equilibration near 650-700 C and 250-500 bars, hornblende that is dominantly OH-bearing (very little Cl or F), and high D/H ratios. To help gain a better understanding of the origin of this unique sample, we have measured the (40)Ar/(39)Ar age (LAP 04840 split 39).

  8. Duration of sedimentation of Creede Formation from 40Ar/39Ar ages

    USGS Publications Warehouse

    Lanphere, Marvin A.

    2000-01-01

    The Oligocene Creede Formation was deposited in the moat of the Creede caldera, which formed as a result of eruption of ythe Snowshoe Mountains Tuff. The Creede Formation in the two moat drill holes contains ash layers that are considered fallout tuffs derived from Fisher Dacite volcanoes that were erupting during accumulation of the Creede Formation. The duration of sedimentation of the Creede Formation could hnot be determinted directly by measuring the ages of the ash layers because 40Ar/39Ar ages of biotite from the asj layers do not stack in the correct stratigraphic order, indicating that the ash layers have been contaminated by biotite from older units. The duration of sedimentation is constrained by the ages of volcanic unites that stratigraphically bracket the Creede Formation. Pooling all ages for the underlyinh Snowshoe Mountain Tuff yields an age of 26.92 ± 0.07 Ma for the unit. The age of the stratigraphically highest lavas of Fisher Dacite, which overlie the Creede Formation, is 26.26 ± 0.04 Ma. The two limits give a maximum duration for sedimentation of the Creede Formation of 0.66 m.y. Using the ages of older Fisher Dacite lavas, on which some beds of the Creede Formation were deposited, a more realistic maximum duration of 0.34 m.y. for sedimentation of the Creede Formation can be determined.

  9. 40Ar/ 39Ar dating of the emplacement of the Muslim Bagh ophiolite, Pakistan

    NASA Astrophysics Data System (ADS)

    Mahmood, Khalid; Boudier, Françoise; Gnos, Edwin; Monié, Patrick; Nicolas, Adolphe

    1995-11-01

    The obduction-related basal part of the Muslim Bagh ophiolite (Baluchistan, Pakistan) and the underlying metamorphic sequence were studied structurally which demonstrated a WSW-ENE-trending thrusting sequence for the initial obduction. 40Ar/ 39Ar measurements on amphiboles and plagioclase from the subophiolitic metamorphic rocks, and on plastically deformed and recrystallized dolerite samples from the base of the sheeted dyke complex give apparent ages between 70.7 ± 5.0 and 65.1 ± 4.1 Ma interpreted as cooling ages dating approximately the formation of the plastic deformation and obduction. The results indicate that the Muslim Bagh ophiolite represents a segment of ocean floor from the small and slow-spreading ocean branch of the Neo-Tethys located between the Indo-Pakistani and the Afro-Arabian plates. The WSW-ENE-oriented obduction of the Muslim Bagh ophiolite onto the Indo-Pakistani continental margin occurred with the convergence of the Neo-Tethys branch during the Late Cretaceous and before the Tertiary collision of the Indo-Pakistani plate with the Eurasian plate.

  10. Structural rejuvenation of the eastern Arabian Shield during continental collision: 40Ar/ 39Ar evidence from the Ar Ridayniyah ophiolitic mélange

    NASA Astrophysics Data System (ADS)

    Al-Saleh, A. M.; Boyle, A. P.

    2001-07-01

    The Ar Ridayniyah ophiolitic mélange is one of a number of such complexes found within or at the peripheries of the Neoproterozoic Al-Amar Suture of the eastern Arabian Shield. This suture is sandwiched between the Ar Rayn island-arc terrane on the east and the much larger Afif continental block to the west, and is thought to represent the site of a 695—680 Ma back-arc basin that separated the two terranes. A thick and monotonous unit of metagraywacke (Abt Schist) underlies most of the suture along with scattered outcrops of metavolcanics and ophiolitic mélange. One of these bodies is the Ar Ridayniyah mélange, which occurs as a longitudinal belt of sheared ultramafic schists enclosing abundant blocks of oceanic serpentinites, as well as subordinate gabbros and basalts. The western boundary of this mélange is defined by the Ar Ridayniyah thrust fault. The 610—600 Ma ages obtained from the metagabbros of this complex are considered to record the reactivation of the Ar Ridayniyah Fault during continental collision, 60 Ma after ophiolite emplacement.

  11. Mass Spectrometric and Langmuir Probe Measurements in Inductively Coupled Plasmas in Ar, CHF3/Ar and CHF3/Ar/O2 Mixtures

    NASA Technical Reports Server (NTRS)

    Kim, J. S.; Rao, M. V. V. S.; Cappelli, M. A.; Sharma, S. P.; Meyyappan, M.; Arnold, Jim (Technical Monitor)

    2000-01-01

    Absolute fluxes and energy distributions of ions in inductively coupled plasmas of Ar, CHF3/Ar, and CHF3/Ar/O2 have been measured. These plasmas were generated in a Gaseous Electronics Conference (GEC) cell modified for inductive coupling at pressures 10-50 mTorr and 100-300 W of 13.56 MHz radio frequency (RF) power in various feedgas mixtures. In pure Ar plasmas, the Ar(+) flux increases linearly with pressure as well as RF-power. Total ion flux in CHF3 mixtures decreases with increase in pressure and also CHF3 concentration. Relative ion fluxes observed in the present studies are analyzed with the help of available cross sections for electron impact ionization and charge-exchange ion-molecule reactions. Measurements of plasma potential, electron and ion number densities, electron energy distribution function, and mean electron energy have also been made in the center of the plasma with a RF compensated Langmuir probe. Plasma potential values are compared with the mean ion energies determined from the measured ion energy distributions and are consistent. Electron temperature, plasma potential, and mean ion energy vary inversely with pressure, but increase with CHF3 content in the mixture.

  12. Ar/Ar age data of muscovite from the Keivy Terrane (central Kola Peninsula, arctic European Russia) imply a prolonged fluid-assisted recrystallisation

    NASA Astrophysics Data System (ADS)

    de Jong, K.; Ruffet, G.; Marker, M.

    2012-04-01

    Single grain muscovite 40Ar/39Ar age data from metasediments of the Keivy Terrane point to a prolonged recrystallisation, and imply that the younger age set in metamorphic terranes with a long history cannot always be simply interpreted as due to late and slow cooling. The Keivy terrane is an element of the Palaeoproterozoic Lapland-Kola collisional belt developed along the northern margin of the Fennoscandian (Baltic) Shield. It comprises a lower series of late Archaean meta-volcanic rocks, intruded by earliest Palaeoproterozoic alkali granites that are covered by strongly deformed quartz-rich kyanite-staurolite-garnet-micaschists of the Keivy unit that have yielded magmatic zircons as young as ~2.35 Ga, which were derived from the substratum's alkaline granite. 40Ar/39Ar step-heating dating with a defocussed laser beam of muscovite grains from seven metasediments of the Keivy unit yielded saddle-shaped age spectra in most experiments. In five out of seven cases the base of the saddle corresponded to a plateau age in the range of 1667 to 1593 Ma (60-90% of the gas release; 1 sigma errors: 1.0-1.2 Ma). We do not simply interpret these 40Ar/39Ar ages in the classical way as due to cooling, because the saddle shape of the spectra enables a more complete and detailed interpretation. Saddle-shaped age spectra may result from the presence of different argon reservoirs in partially recrystallised and chemically distinct micas that degas over a different energy interval: a primary, not recrystallised or inherited domain (low and high temperature steps) and a newly formed or recrystallised one (saddle minimum in the intermediate steps). The younger subdomains formed by growth or recrystallisation could characterise the last isotopic record during an extended (re)crystallisation history. It is striking that 1612 and 1615 Ma saddle minimum ages in two samples correspond to a plateau age of 1612 Ma in another sample. Also elevated high and/or low temperature apparent ages of

  13. 40Ar/39Ar and (U-Th)/He - 4He/3He geochronology of landscape evolution and channel iron deposit genesis at Lynn Peak, Western Australia

    NASA Astrophysics Data System (ADS)

    Vasconcelos, Paulo M.; Heim, Jonathan A.; Farley, Kenneth A.; Monteiro, Hevelyn; Waltenberg, Kathryn

    2013-09-01

    (U-Th)/He geochronology of authigenic goethite cements from the Lynn Peak channel iron deposit (CID), Hamersley Province, Western Australia, reveals a history of mineral precipitation ranging from ca. 33 to 14 Ma. Massive goethites from nearby weathering profiles at Roy Hill North, a possible source of detrital material during the aggradation of the Lynn Peak channels, yield (U-Th)/He results as old as ca. 64 Ma. The combination of (U-Th)/He geochronology with incremental outgassing 4He/3He studies on proton-irradiated samples reveals that Lynn Peak goethites host radiogenic 4He in low retentivity (LRD) and high retentivity (HRD) domains and that the HRDs account for most of the sample mass and have lost very little of their original 4He over geologic time. Such high retentivity is especially notable given the goethites were collected from the surface, where they were subject to significant heating by solar irradiation. Minor contamination by detrital fragments of potentially 4He-rich primary phases (e.g., rutile, ilmenite, zircon) occurs in some samples. Fortunately, the 4He/3He method permits characterization of this extraneous 4He component, which is small (<10 wt.% of the total 4He in the goethite) and can be corrected out in estimating the goethite formation age. These results indicate that the Lynn Peak channel was already aggraded and undergoing goethite cementation by ca. 33 Ma. The history of aggradation and channel cementation independently measured through 40Ar/39Ar geochronology is consistent with that obtained from the (U-Th)/He and 4He/3He record. Laser incremental-heating 40Ar/39Ar geochronology of detrital and authigenic Mn oxides, primarily cryptomelane (KMn8O16·xH2O), from the same locality in the Lynn Peak channel reveals that detrital oxides are older than ca. 44 Ma (and as old as ca. 65 Ma) and authigenic oxides are younger than ca. 35 Ma and as young as ca. 16 Ma. Authigenic cryptomelane precipitation and channel cementation occurred

  14. 40Ar/39Ar dating of Pleistocene tuffs: an accurate age for the Matuyama-Brunhes geomagnetic reversal (MBGR)

    NASA Astrophysics Data System (ADS)

    Mark, D. F.; Renne, P. R.; Morgan, L. E.; Deino, A.; Smith, V. C.; Ellis, B. S.; Pearce, N. J.

    2012-12-01

    Recent recalibrations of the 40Ar/39Ar system [1,2] reveal inconsistencies with some previous ages inferred for the MBGR. An Ar/Ar age [3] for the Bishop Tuff (BT) (which post-dates the MBGR by at least 15.3 ± 2.2 ka [3]) recalculated [2] yields an age of 778.0 ± 3.8 ka (1σ, full systematic uncertainty). The age is c. 10 ka older than the BT zircon ID-TIMS U-Pb age [4] and places the MBGR at c. 793 ka, c. 13 and 20 ka older than astronomical ages for the MBGR of 780 ka [5] and 773 ka [6], respectively. To determine an accurate age for the MBGR, we have made a series of 40Ar/39Ar age determinations for Pleistocene tuffs from both Indonesia and North America that have direct relationships to the MBGR. Blind analyses were conducted at SUERC and BGC. We observed excellent inter-laboratory agreement and no systematic offset in data. Ar/Ar ages are reported relative to [2] (1σ, full systematic uncertainty). Drill cores from ODP Site 758 show the precise location of the MBGR. Below the MBGR are two distal tephra horizons that we have identified as products of two temporally distinct Old Toba Tuff (OTT) eruptions (layer d OTT1 and layer D OTT2). Continuous sedimentation between OTT1 (802.8 ± 0.7 ka, n = 100, MSWD 1.2) and OTT2 (796.2 ± 0.8 ka, n = 62, MSWD 1.3) allows for calculation of an accurate sedimentation rate and for extrapolation of an age from OTT2 to the MBGR. Data define an age for the MBGR of 795.2 ± 0.9 ka. Using tephra above the MBGR boundary, the Middle Toba Tuff (layer C) and Young Toba Tuff (layer A), extrapolation down core supports a MBGR age of c. 795 ka. Recent age data for BT sanidine reported relative to FCs at 28.172 Ma (767.4 ± 1.1 Ma) [7] oddly yielded an Ar/Ar age that was indistinguishable from the BT zircon U-Pb age [4], which is consistent with previous 40Ar/39Ar age measurements made relative to FCs at 28.02 Ma [3]. Thus we made a series of 40Ar/39Ar measurements on the exact same sample as used by Rivera et al. [7] and observed

  15. High Precision Ar/Ar Ages of Coso Volcanic Field Rhyolites: A Requirement for Constraining Eruption and Subvolcanic Time Scales

    NASA Astrophysics Data System (ADS)

    Simon, J. I.; Renne, P. R.; Vazquez, J.

    2006-12-01

    Study of the extended volcanic history and petrology at Coso Volcanic Field, CA has led to fundamental ideas related to silicic magma evolution and eruption prediction. Unfortunately, tests of these and related models for the time scales of subvolcanic processes at Coso are limited because relatively few modern geochronological constraints have been published. For example, tighter age constraints are needed to test the veracity of the volume-age "time-prediction" model of Bacon (1982) wherein the next eruption can be predicted reasonably well from a long-term eruption rate that simply considers the total volume of Coso rhyolites over an appropriate time span. At Coso, reported eruption events are mean ages comprising K-Ar ± hydration rind glass ages grouped by rock chemical similarities. Here we present new Ar/Ar ages for seven Pleistocene domes from groups 4, 6, and 7. Sanidine and anorthoclase were separated from nearly aphyric obsidian and pumiceous glasses. Total fusion and step-heating feldspar and glass analyses were performed. Ar/Ar spectra derived from laser step-heating of samples from previously dated domes show that excess 40Ar contamination likely biased some K-Ar results. Modern Ar/Ar analyses of the studied rhyolites with disturbed model (i.e., assuming atmospheric initial Ar) ages, but well-defined Ar isochrons still provide accurate eruption ages. In detail, a 229 ±6 ka (2 se) age is determined for the most northern dome, which is ~60 ka older than one reported K-Ar date and the nominal age for Group 4 rhyolites and ~150-370 ka younger than four other reported K-Ar dates. Based on pre-eruption zircon ages from other magma centers, the inaccuracies and magnitude of these age shifts could produce apparent magma residence times from ≥500 ka to meaningless futuristic storage times. New ages for the southern domes are older than the reported mean Group 6 age of ~90 ka. It is probable that the anomalously young K-Ar dates reflect incomplete extraction

  16. The Effects of Androgens on Murine Cortical Bone Do Not Require AR or ERα Signaling in Osteoblasts and Osteoclasts

    PubMed Central

    Ucer, Serra; Iyer, Srividhya; Bartell, Shoshana M; Martin-Millan, Marta; Han, Li; Kim, Ha-Neui; Weinstein, Robert S; Jilka, Robert L; O’Brien, Charles A; Almeida, Maria; Manolagas, Stavros C

    2016-01-01

    In men, androgens are critical for the acquisition and maintenance of bone mass in both the cortical and cancellous bone compartment. Male mice with targeted deletion of the androgen receptor (AR) in mature osteoblasts or osteocytes have lower cancellous bone mass, but no cortical bone phenotype. We have investigated the possibility that the effects of androgens on the cortical compartment result from AR signaling in osteoprogenitors or cells of the osteoclast lineage; or via estrogen receptor alpha (ERα) signaling in either or both of these two cell types upon conversion of testosterone to estradiol. To this end, we generated mice with targeted deletion of an AR or an ERα allele in the mesenchymal (ARf/y;Prx1-Cre or ERαf/f;Osx1-Cre) or myeloid cell lineage (ARf/y; LysM-Cre or ERαf/f;LysM-Cre) and their descendants. Male ARf/y;Prx1-Cre mice exhibited decreased bone volume and trabecular number, and increased osteoclast number in the cancellous compartment. Moreover, they did not undergo the loss of cancellous bone volume and trabecular number caused by orchidectomy (ORX) in their littermate controls. In contrast, ARf/y;LysM-Cre, ERαf/f; Osx1-Cre, or ERαf/f;LysM-Cre mice had no cancellous bone phenotype at baseline and lost the same amount of cancellous bone as their controls following ORX. Most unexpectedly, adult males of all four models had no discernible cortical bone phenotype at baseline, and lost the same amount of cortical bone as their littermate controls after ORX. Recapitulation of the effects of ORX by AR deletion only in the ARf/y;Prx1-Cre mice indicates that the effects of androgens on cancellous bone result from AR signaling in osteoblasts—not on osteoclasts or via aromatization. The effects of androgens on cortical bone mass, on the other hand, do not require AR or ERα signaling in any cell type across the osteoblast or osteoclast differentiation lineage. Therefore, androgens must exert their effects indirectly by actions on some other cell

  17. The Thermo Scientific HELIX-SFT noble gas mass spectrometer: (preliminary) performance for 40Ar/39Ar geochronology

    NASA Astrophysics Data System (ADS)

    Barfod, D. N.; Mark, D. F.; Morgan, L. E.; Tomkinson, T.; Stuart, F.; Imlach, J.; Hamilton, D.

    2011-12-01

    The Thermo Scientific HELIX-platform Split Flight Tube (HELIX-SFT) noble gas mass spectrometer is specifically designed for simultaneous collection of helium isotopes. The high mass spur houses a switchable 1011 - 1012 Ω resistor Faraday cup and the low mass spur a digital pulse-counting secondary electron multiplier (SEM). We have acquired the HELIX-SFT with the specific intention to measure argon isotopes for 40Ar/39Ar geochronology. This contribution will discuss preliminary performance (resolution, reproducibility, precision etc.) with respect to measuring argon isotope ratios for 40Ar/39Ar dating of geological materials. We anticipate the greatest impact for 40Ar/39Ar dating will be increased accuracy and precision, especially as we approach the techniques younger limit. Working with Thermo Scientific we have subtly modified the source, alpha and collector slits of the HELIX-SFT mass spectrometer to improve its resolution for resolving isobaric interferences at masses 36 to 40. The enhanced performance will allow for accurate and precise measurement of argon isotopes. Preliminary investigations show that we can obtain a valley resolution of >700 and >1300 (compared to standard HELIX-SFT specifications of >400 and >700) for the high and low mass spurs, respectively. The improvement allows for full resolution of hydrocarbons (C3+) at masses 37 - 40 and almost full resolution at mass 36. The HELIX-SFT will collect data in dual collection mode with 40Ar+ ion beams measured using the switchable 1011 - 1012 Ω resistor Faraday cup and 39Ar through 36Ar measured using the SEM. The HELIX-SFT requires Faraday-SEM inter-calibration but negates the necessity to inter-calibrate multiple electron multipliers. We will further present preliminary data from the dating of mineral standards: Alder Creek sanidine, Fish Canyon sanidine and Mount Dromedary biotite (GA1550).

  18. Atmospheric Pressure Plasma Jet in Ar and O2/Ar Mixtures: Properties and High Performance for Surface Cleaning

    NASA Astrophysics Data System (ADS)

    Jin, Ying; Ren, Chunsheng; Yang, Liang; Zhang, Jialiang; Wang, Dezhen

    2013-12-01

    An atmospheric pressure plasma jet generated in Ar and O2/Ar mixtures has been investigated by specially designed equipment with double power electrodes at 20~32 kHz, and their effects on the cleaning of surfaces have been studied. Properties of the jet discharge are studied by electrical diagnostics, including the waveform of discharge voltage, discharge current and the Q-V Lissajous figures. The optical emission spectroscopy is used to measure the plasma parameters, such as the excitation temperature and the gas temperature. It is found that the consumed power and the excitation temperature increase with increase of the discharge frequency. On the other hand, at the same discharge frequency, these parameters in O2/Ar mixture plasma are found to be much larger. The effect on surface cleaning is studied from the changes in the contact angle. For Ar plasma jet, the contact angle decreases with increase of the discharge frequency. For O2/Ar mixture plasma jet, the contact angle decreases with increase of discharge frequency up to 26 kHz, however, further increase of discharge frequency does not show further decrease in the contact angle. At the same discharge frequency, the contact angle after O2/Ar mixture plasma cleaning is found to be much lower compared to the case of pure Ar. From the results of quadrupole mass-spectrum analysis, we can identify more fragment molecules of CO and H2O in the emitted gases after O2/Ar plasma jet treatment compared with Ar plasma jet treatment, which are produced by the decomposition of surface organic contaminants during the cleaning process.

  19. Geochronological constraints on the age of a Permo-Triassic impact event: U-Pb and 40Ar/39Ar results for the 40 km Araguainha structure of central Brazil

    NASA Astrophysics Data System (ADS)

    Tohver, E.; Lana, C.; Cawood, P. A.; Fletcher, I. R.; Jourdan, F.; Sherlock, S.; Rasmussen, B.; Trindade, R. I. F.; Yokoyama, E.; Souza Filho, C. R.; Marangoni, Y.

    2012-06-01

    Impact cratering has been a fundamental geological process in Earth history with major ramifications for the biosphere. The complexity of shocked and melted rocks within impact structures presents difficulties for accurate and precise radiogenic isotope age determination, hampering the assessment of the effects of an individual event in the geological record. We demonstrate the utility of a multi-chronometer approach in our study of samples from the 40 km diameter Araguainha impact structure of central Brazil. Samples of uplifted basement granite display abundant evidence of shock deformation, but U/Pb ages of shocked zircons and the 40Ar/39Ar ages of feldspar from the granite largely preserve the igneous crystallization and cooling history. Mixed results are obtained from in situ40Ar/39Ar spot analyses of shocked igneous biotites in the granite, with deformation along kink-bands resulting in highly localized, partial resetting in these grains. Likewise, spot analyses of perlitic glass from pseudotachylitic breccia samples reflect a combination of argon inheritance from wall rock material, the age of the glass itself, and post-impact devitrification. The timing of crater formation is better assessed using samples of impact-generated melt rock where isotopic resetting is associated with textural evidence of melting and in situ crystallization. Granular aggregates of neocrystallized zircon form a cluster of ten U-Pb ages that yield a “Concordia” age of 247.8 ± 3.8 Ma. The possibility of Pb loss from this population suggests that this is a minimum age for the impact event. The best evidence for the age of the impact comes from the U-Th-Pb dating of neocrystallized monazite and 40Ar/39Ar step heating of three separate populations of post-impact, inclusion-rich quartz grains that are derived from the infill of miarolitic cavities. The 206Pb/238U age of 254.5 ± 3.2 Ma (2σ error) and 208Pb/232Th age of 255.2 ± 4.8 Ma (2σ error) of monazite, together with the

  20. Differential regulation of metabolic pathways by androgen receptor (AR) and its constitutively active splice variant, AR-V7, in prostate cancer cells.

    PubMed

    Shafi, Ayesha A; Putluri, Vasanta; Arnold, James M; Tsouko, Efrosini; Maity, Suman; Roberts, Justin M; Coarfa, Cristian; Frigo, Daniel E; Putluri, Nagireddy; Sreekumar, Arun; Weigel, Nancy L

    2015-10-13

    Metastatic prostate cancer (PCa) is primarily an androgen-dependent disease, which is treated with androgen deprivation therapy (ADT). Tumors usually develop resistance (castration-resistant PCa [CRPC]), but remain androgen receptor (AR) dependent. Numerous mechanisms for AR-dependent resistance have been identified including expression of constitutively active AR splice variants lacking the hormone-binding domain. Recent clinical studies show that expression of the best-characterized AR variant, AR-V7, correlates with resistance to ADT and poor outcome. Whether AR-V7 is simply a constitutively active substitute for AR or has novel gene targets that cause unique downstream changes is unresolved. Several studies have shown that AR activation alters cell metabolism. Using LNCaP cells with inducible expression of AR-V7 as a model system, we found that AR-V7 stimulated growth, migration, and glycolysis measured by ECAR (extracellular acidification rate) similar to AR. However, further analyses using metabolomics and metabolic flux assays revealed several differences. Whereas AR increased citrate levels, AR-V7 reduced citrate mirroring metabolic shifts observed in CRPC patients. Flux analyses indicate that the low citrate is a result of enhanced utilization rather than a failure to synthesize citrate. Moreover, flux assays suggested that compared to AR, AR-V7 exhibits increased dependence on glutaminolysis and reductive carboxylation to produce some of the TCA (tricarboxylic acid cycle) metabolites. These findings suggest that these unique actions represent potential therapeutic targets.

  1. Human immunoglobulin allotypes: previously unrecognized determinants and alleles defined with monoclonal antibodies.

    PubMed Central

    Zelaschi, D; Newby, C; Parsons, M; van West, B; Cavalli-Sforza, L L; Herzenberg, L A; Herzenberg, L A

    1983-01-01

    The highly polymorphic system of serologically defined genetic markers on human IgG heavy chains (Gm allotypes) is second only to the HLA complex in terms of the large number of determinants, alleles, and haplotypes that can be used for analyses of disease associations and other genetic studies. However, present typing methods are based on the use of anti-Gm antisera that are derived mainly from fortuitously immunized human donors, often requiring processing before use, and must be used in a hemagglutination-inhibition assay that cannot be used in typing for isoallotypic determinants (currently termed "non-markers"). In studies presented here, we describe an allotyping system that utilizes monoclonal antibodies in a "sandwich" modification of the solid-phase radioimmunoassay, which is capable of reliable quantitative typing of allotypic, isoallotypic, and isotypic immunoglobulin determinants. We show that these highly reproducible, easily disseminated, and essentially inexhaustible reagents can be used for rapid, sensitive, and quantitative Gm typing. Using this system we define two previously unrecognized Gm determinants, one of which, found to date only in Caucasians, is different from all known Gm markers and thus defines previously unrecognized alleles and haplotypes. The other determinant co-segregates with the conventional G3m(b1) marker but is distinct from that marker on serological grounds. The successful preparation of mouse monoclonal antibodies that detect human Gm allotypic differences and the development of an assay system capable of typing isoallotypic as well as allotypic determinants opens the way to further dissection and application of this rich genetic system. PMID:6190180

  2. Single-crystal 40Ar/39Ar incremental heating reveals bimodal sanidine ages in the Bishop Tuff

    NASA Astrophysics Data System (ADS)

    Andersen, N. L.; Jicha, B. R.; Singer, B. S.

    2015-12-01

    The 650 km3 Bishop Tuff (BT) is among the most studied volcanic deposits because it is an extensive marker bed deposited just after the Matuyama-Brunhes boundary. Reconstructions of the vast BT magma reservoir from which high-silica rhyolite erupted have long influenced thinking about how large silicic magma systems are assembled, crystallized, and mixed. Yet, the longevity of the high silica rhyolitic melt and exact timing of the eruption remain controversial due to recent conflicting 40Ar/39Ar sanidine vs. SIMS and ID-TIMS U-Pb zircon dates. We have undertaken 21 40Ar/39Ar incremental heating ages on 2 mm BT sanidine crystals from pumice in 3 widely separated outcrops of early-erupted fall and flow units. Plateau ages yield a bimodal distribution: a younger group has a mean of 766 ka and an older group gives a range between 772 and 782 ka. The younger population is concordant with the youngest ID-TIMS and SIMS U-Pb zircon ages recently published, as well as the astronomical age of BT in marine sediment. Of 21 crystals, 17 yield older, non-plateau, steps likely affected by excess Ar that would bias traditional 40Ar/39Ar total crystal fusion ages. The small spread in older sanidine ages, together with 25+ kyr of pre-eruptive zircon growth, suggest that the older sanidines are not partially outgassed xenocrysts. A bimodal 40Ar/39Ar age distribution implies that some fraction of rhyolitic melt cooled below the Ar closure temperature at least 10 ky prior to eruption. We propose that rapid "thawing" of a crystalline mush layer released older crystals into rhyolitic melt from which sanidine also nucleated and grew immediately prior to the eruption. High precision 40Ar/39Ar dating can thus provide essential information on thermo-physical processes at the millenial time scale that are critical to interpreting U-Pb zircon age distributions that are complicated by large uncertainties associated with zircon-melt U-Th systematics.

  3. Astronomical calibration of 40Ar/39Ar reference minerals using high-precision, multi-collector (ARGUSVI) mass spectrometry

    NASA Astrophysics Data System (ADS)

    Phillips, D.; Matchan, E. L.; Honda, M.; Kuiper, K. F.

    2017-01-01

    The new generation of multi-collector mass spectrometers (e.g. ARGUSVI) permit ultra-high precision (<0.1%) 40Ar/39Ar geochronology of rocks and minerals. At the same time, the 40Ar/39Ar method is limited by relatively large uncertainties (>1%) in 40K decay constants and the ages of natural reference minerals that form the basis of the technique. For example, reported ages for widely used 40Ar/39Ar reference materials, such as the ca. 28 Ma Fish Canyon Tuff sanidine (FCTs) and the ca. 1.2 Ma Alder Creek Rhyolite sanidine (ACRs), vary by >1%. Recent attempts to independently calibrate these reference minerals have focused on K-Ar analyses of the same minerals and inter-comparisons with astronomically tuned tephras in sedimentary sequences and U-Pb zircon ages from volcanic rocks. Most of these studies used older generation (effectively single-collector) mass spectrometers that employed peak-jumping analytical methods to acquire 40Ar/39Ar data. In this study, we reassess the inter-calibration and ages of commonly used 40Ar/39Ar reference minerals Fish Canyon Tuff sanidine (FCTs), Alder Creek Rhyolite sanidine (ACRs) and Mount Dromedary biotite (MD2b; equivalent to GA-1550 biotite), relative to the astronomically tuned age of A1 Tephra sanidine (A1Ts), Faneromeni section, Crete (Rivera et al., 2011), using a multi-collector ARGUSVI mass spectrometer. These analyses confirm the exceptional precision capability (<0.1%) of this system, compared to most previous studies. All sanidine samples (FCTs, ACRs and A1Ts) exhibit discordant 40Ar/39Ar step-heating spectra, with generally monotonically increasing ages (∼1% gradients). The similarity in these patterns, mass-dependent fractionation modeling, and results from step-crushing experiments on FCTs, which yield younger apparent ages, suggest that the discordance may be due to a combination of recoil loss and redistribution of 39ArK and isotope mass fractionation. In contrast to our previous inferences, these results imply

  4. RadNet Air Data From Fort Smith, AR

    EPA Pesticide Factsheets

    This page presents radiation air monitoring and air filter analysis data for Fort Smith, AR from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

  5. The alfalfa research program in USDA-ARS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alfalfa research is currently conducted by scientists employed by the USDA-Agricultural Research Service (ARS) in nine laboratories located in Minnesota (Saint Paul), Wisconsin (Madison, Prairie du Sac, Marshfield), Maryland (Beltsville), Utah (Logan), Washington (Prosser, Pullman), and Iowa (Ames)....

  6. RadNet Air Data From Little Rock, AR

    EPA Pesticide Factsheets

    This page presents radiation air monitoring and air filter analysis data for Little Rock, AR from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

  7. Characterization of 18 new BoLA-DRB3 alleles.

    PubMed

    Maillard, J C; Renard, C; Chardon, P; Chantal, I; Bensaid, A

    1999-06-01

    The second exon of the bovine MHC class II DRB3 gene was amplified by polymerase chain reaction (PCR) from DNA samples of 568 zebu Brahman cattle (Bos indicus) from Martinique (French West Indies). Cloning of these PCR products allowed the isolation of both alleles from each animal, which were characterized by the PCR-restriction fragment length polymorphism (RFLP) technique using the restriction enzymes RsaI, BstYI and HaeIII. Four new PCR-RFLP patterns were obtained by digestion with RsaI. These patterns were named 'v', 'w', 'x' and 'y' continuing the accepted nomenclature. Sequencing of each allele allowed the identification of 18 new BoLA-DRB3 exon 2 nucleotide sequences and their deduced amino acid sequences.

  8. Early allelic selection in maize as revealed by ancient DNA.

    PubMed

    Jaenicke-Després, Viviane; Buckler, Ed S; Smith, Bruce D; Gilbert, M Thomas P; Cooper, Alan; Doebley, John; Pääbo, Svante

    2003-11-14

    Maize was domesticated from teosinte, a wild grass, by approximately 6300 years ago in Mexico. After initial domestication, early farmers continued to select for advantageous morphological and biochemical traits in this important crop. However, the timing and sequence of character selection are, thus far, known only for morphological features discernible in corn cobs. We have analyzed three genes involved in the control of plant architecture, storage protein synthesis, and starch production from archaeological maize samples from Mexico and the southwestern United States. The results reveal that the alleles typical of contemporary maize were present in Mexican maize by 4400 years ago. However, as recently as 2000 years ago, allelic selection at one of the genes may not yet have been complete.

  9. Selective AR Modulators that Distinguish Proliferative from Differentiative Gene Promoters

    DTIC Science & Technology

    2015-08-01

    AWARD NUMBER: W81XWH-14-1-0292 TITLE: Selective AR Modulators that Distinguish Proliferative from Differentiative Gene Promoters PRINCIPAL...30 Jul 2014 - 29 Jul 2015 4. TITLE AND SUBTITLE Selective AR Modulators that Distinguish Proliferative from Differentiative Gene Promoters 5a...differ in androgen response elements (AREs), with genes driving proliferation relying on consensus inverted repeats (cARE) and genes promoting

  10. AR Pavonis - The Rosetta Stone of the symbiotics

    NASA Technical Reports Server (NTRS)

    Slovak, M. H.

    1982-01-01

    AR Pav is considered with respect to the early history and observations, the light curve, spectroscopic properties, and recent observations. It is suggested that recent observations tend to confirm the validity of the binary model proposed for AR Pav by Thackeray and Hutchings (1974). The secondary appears as an M3 giant showing normal infrared properties. The nature of the hot primary, however, remains uncertain as it appears obscured by an accretion 'shell' both during and outside of eclipse.

  11. Chemical Abundances in the Extremely Carbon-rich and Xenon-rich Halo Planetary Nebula H4-1

    NASA Astrophysics Data System (ADS)

    Otsuka, Masaaki; Tajitsu, Akito

    2013-12-01

    We performed detailed chemical abundance analysis of the extremely metal-poor ([Ar/H] ~ -2) halo planetary nebula (PN) H4-1 based on the multi-wavelength spectra from Subaru/HDS, GALEX, SDSS, and Spitzer/IRS and determined the abundances of 10 elements. The C and O abundances were derived from collisionally excited lines (CELs) and are almost consistent with abundances from recombination lines (RLs). We demonstrated that the large discrepancy in the C abundance between CEL and RL in H4-1 can be solved using the temperature fluctuation model. We reported the first detection of the [Xe III] λ5846 line in H4-1 and determination of its elemental abundance ([Xe/H] > +0.48). H4-1 is the most Xe-rich PN among the Xe-detected PNe. The observed abundances are close to the theoretical prediction by a 2.0 M ⊙ single star model with an initially element rich ([r/Fe] = +2.0 dex) rapid neutron-capture process (r-process). The observed Xe abundance would be a product of the r-process in primordial supernovae. The [C/O]-[Ba/(Eu or Xe)] diagram suggests that the progenitor of H4-1 shares the evolution with carbon-enhanced metal-poor (CEMP)-r/s and CEMP-no stars. The progenitor of H4-1 is presumably a binary formed in an r-process-rich environment.

  12. Natural Allelic Variations in Highly Polyploidy Saccharum Complex

    PubMed Central

    Song, Jian; Yang, Xiping; Resende, Marcio F. R.; Neves, Leandro G.; Todd, James; Zhang, Jisen; Comstock, Jack C.; Wang, Jianping

    2016-01-01

    Sugarcane (Saccharum spp.) is an important sugar and biofuel crop with high polyploid and complex genomes. The Saccharum complex, comprised of Saccharum genus and a few related genera, are important genetic resources for sugarcane breeding. A large amount of natural variation exists within the Saccharum complex. Though understanding their allelic variation has been challenging, it is critical to dissect allelic structure and to identify the alleles controlling important traits in sugarcane. To characterize natural variations in Saccharum complex, a target enrichment sequencing approach was used to assay 12 representative germplasm accessions. In total, 55,946 highly efficient probes were designed based on the sorghum genome and sugarcane unigene set targeting a total of 6 Mb of the sugarcane genome. A pipeline specifically tailored for polyploid sequence variants and genotype calling was established. BWA-mem and sorghum genome approved to be an acceptable aligner and reference for sugarcane target enrichment sequence analysis, respectively. Genetic variations including 1,166,066 non-redundant SNPs, 150,421 InDels, 919 gene copy number variations, and 1,257 gene presence/absence variations were detected. SNPs from three different callers (Samtools, Freebayes, and GATK) were compared and the validation rates were nearly 90%. Based on the SNP loci of each accession and their ploidy levels, 999,258 single dosage SNPs were identified and most loci were estimated as largely homozygotes. An average of 34,397 haplotype blocks for each accession was inferred. The highest divergence time among the Saccharum spp. was estimated as 1.2 million years ago (MYA). Saccharum spp. diverged from Erianthus and Sorghum approximately 5 and 6 MYA, respectively. The target enrichment sequencing approach provided an effective way to discover and catalog natural allelic variation in highly polyploid or heterozygous genomes. PMID:27375658

  13. Natural Allelic Variations in Highly Polyploidy Saccharum Complex.

    PubMed

    Song, Jian; Yang, Xiping; Resende, Marcio F R; Neves, Leandro G; Todd, James; Zhang, Jisen; Comstock, Jack C; Wang, Jianping

    2016-01-01

    Sugarcane (Saccharum spp.) is an important sugar and biofuel crop with high polyploid and complex genomes. The Saccharum complex, comprised of Saccharum genus and a few related genera, are important genetic resources for sugarcane breeding. A large amount of natural variation exists within the Saccharum complex. Though understanding their allelic variation has been challenging, it is critical to dissect allelic structure and to identify the alleles controlling important traits in sugarcane. To characterize natural variations in Saccharum complex, a target enrichment sequencing approach was used to assay 12 representative germplasm accessions. In total, 55,946 highly efficient probes were designed based on the sorghum genome and sugarcane unigene set targeting a total of 6 Mb of the sugarcane genome. A pipeline specifically tailored for polyploid sequence variants and genotype calling was established. BWA-mem and sorghum genome approved to be an acceptable aligner and reference for sugarcane target enrichment sequence analysis, respectively. Genetic variations including 1,166,066 non-redundant SNPs, 150,421 InDels, 919 gene copy number variations, and 1,257 gene presence/absence variations were detected. SNPs from three different callers (Samtools, Freebayes, and GATK) were compared and the validation rates were nearly 90%. Based on the SNP loci of each accession and their ploidy levels, 999,258 single dosage SNPs were identified and most loci were estimated as largely homozygotes. An average of 34,397 haplotype blocks for each accession was inferred. The highest divergence time among the Saccharum spp. was estimated as 1.2 million years ago (MYA). Saccharum spp. diverged from Erianthus and Sorghum approximately 5 and 6 MYA, respectively. The target enrichment sequencing approach provided an effective way to discover and catalog natural allelic variation in highly polyploid or heterozygous genomes.

  14. Allelic exchange in Mycobacterium tuberculosis with long linear recombination substrates.

    PubMed Central

    Balasubramanian, V; Pavelka, M S; Bardarov, S S; Martin, J; Weisbrod, T R; McAdam, R A; Bloom, B R; Jacobs, W R

    1996-01-01

    Genetic studies of Mycobacterium tuberculosis have been greatly hampered by the inability to introduce specific chromosomal mutations. Whereas the ability to perform allelic exchanges has provided a useful method of gene disruption in other organisms, in the clinically important species of mycobacteria, such as M. tuberculosis and Mycobacterium bovis, similar approaches have thus far been unsuccessful. In this communication, we report the development of a shuttle mutagenesis strategy that involves the use of long linear recombination substrates to reproducibly obtain recombinants by allelic exchange in M. tuberculosis. Long linear recombination substrates, approximately 40 to 50 kb in length, were generated by constructing libraries in the excisable cosmid vector pYUB328. The cosmid vector could be readily excised from the recombinant cosmids by digestion with PacI, a restriction endonuclease for which there exist few, if any, sites in mycobacterial genomes. A cosmid containing the mycobacterial leuD gene was isolated, and a selectable marker conferring resistance to kanamycin was inserted into the leuD gene in the recombinant cosmid by interplasmid recombination in Escherichia coli. A long linear recombination substrate containing the insertionally mutated leuD gene was generated by PacI digestion. Electroporation of this recombination substrate containing the insertionally mutated leuD allele resulted in the generation of leucine auxotrophic mutants by homologous recombination in 6% of the kanamycin-resistant transformants for both the Erdman and H37Rv strains of M. tuberculosis. The ability to perform allelic exchanges provides an important approach for investigating the biology of this pathogen as well as developing new live-cell M. tuberculosis-based vaccines. PMID:8550428

  15. Citrobacter spp. as a source of qnrB Alleles.

    PubMed

    Jacoby, George A; Griffin, Caitlin M; Hooper, David C

    2011-11-01

    qnrB is the most common of the five qnr families and has the greatest number of allelic variants. Almost two-thirds of the qnrB alleles have been reported in Citrobacter spp., and several were shown to be located on the chromosome. In this study, PCR was used to investigate the prevalence of plasmid-mediated quinolone resistance genes in 71 clinical isolates belonging to the Citrobacter freundii complex. Thirty-seven percent contained qnrB alleles, including 7 (qnrB32 to qnrB38) that were novel and 1 pseudogene, while none contained qnrA, qnrC, qnrD, qnrS, or aac(6')-Ib-cr. When the strains were arrayed by related 16S rRNA sequence and further separated into subspecies by biochemical criteria, clustering of qnrB-positive strains was evident. In only two strains with qnrB2 and qnrB4 was quinolone resistance transferable by conjugation, and only these strains contained the ISCR1 sequence that is often associated with qnrB on plasmids. Five of 26 qnrB-positive strains contained integrase genes, but these included the strains with qnrB2 and qnrB4 as well as two strains with other transmissible plasmids. In a fully sequenced genome of Citrobacter youngae, a member of the C. freundii complex, another novel qnrB allele, qnrB39, occurs in a sequence of genes that is 90% identical to sequence surrounding integron-associated qnrB4 incorporated into plasmids. The chromosome of Citrobacter is the likely source of plasmid-mediated qnrB.

  16. Fast spatial ancestry via flexible allele frequency surfaces

    PubMed Central

    Rañola, John Michael; Novembre, John; Lange, Kenneth

    2014-01-01

    Motivation: Unique modeling and computational challenges arise in locating the geographic origin of individuals based on their genetic backgrounds. Single-nucleotide polymorphisms (SNPs) vary widely in informativeness, allele frequencies change non-linearly with geography and reliable localization requires evidence to be integrated across a multitude of SNPs. These problems become even more acute for individuals of mixed ancestry. It is hardly surprising that matching genetic models to computational constraints has limited the development of methods for estimating geographic origins. We attack these related problems by borrowing ideas from image processing and optimization theory. Our proposed model divides the region of interest into pixels and operates SNP by SNP. We estimate allele frequencies across the landscape by maximizing a product of binomial likelihoods penalized by nearest neighbor interactions. Penalization smooths allele frequency estimates and promotes estimation at pixels with no data. Maximization is accomplished by a minorize–maximize (MM) algorithm. Once allele frequency surfaces are available, one can apply Bayes’ rule to compute the posterior probability that each pixel is the pixel of origin of a given person. Placement of admixed individuals on the landscape is more complicated and requires estimation of the fractional contribution of each pixel to a person’s genome. This estimation problem also succumbs to a penalized MM algorithm. Results: We applied the model to the Population Reference Sample (POPRES) data. The model gives better localization for both unmixed and admixed individuals than existing methods despite using just a small fraction of the available SNPs. Computing times are comparable with the best competing software. Availability and implementation: Software will be freely available as the OriGen package in R. Contact: ranolaj@uw.edu or klange@ucla.edu Supplementary information: Supplementary data are available at

  17. Arsenic resistance strategy in Pantoea sp. IMH: Organization, function and evolution of ars genes

    PubMed Central

    Wang, Liying; Zhuang, Xuliang; Zhuang, Guoqiang; Jing, Chuanyong

    2016-01-01

    Pantoea sp. IMH is the only bacterium found in genus Pantoea with a high As resistance capacity, but its molecular mechanism is unknown. Herein, the organization, function, and evolution of ars genes in IMH are studied starting with analysis of the whole genome. Two ars systems - ars1 (arsR1B1C1H1) and ars2 (arsR2B2C2H2) - with low sequence homology and two arsC-like genes, were found in the IMH genome. Both ars1 and ars2 are involved in the As resistance, where ars1 is the major contributor at 15 °C and ars2 at 30 °C. The difference in the behavior of these two ars systems is attributed to the disparate activities of their arsR promoters at different temperatures. Sequence analysis based on concatenated ArsRBC indicates that ars1 and ars2 clusters may be acquired from Franconibacter helveticus LMG23732 and Serratia marcescens (plasmid R478), respectively, by horizontal gene transfer (HGT). Nevertheless, two arsC-like genes, probably arising from the duplication of arsC, do not contribute to the As resistance. Our results indicate that Pantoea sp. IMH acquired two different As resistance genetic systems by HGT, allowing the colonization of changing ecosystems, and highlighting the flexible adaptation of microorganisms to resist As. PMID:27966630

  18. Improving the Precision of the Half Life of 34Ar

    NASA Astrophysics Data System (ADS)

    Iacob, V. E.; Hardy, J. C.; Bencomo, M.; Chen, L.; Horvat, V.; Nica, N.; Park, H. I.

    2016-03-01

    Currently, precise ft-values measured for superallowed 0+ -->0+ β transitions provide the most accurate value for Vud, the up-down quark mixing element of the Cabibbo-Kobayashi-Maskawa (CKM) matrix. This enables the most demanding test of CKM unitarity, one of the pillars of the Standard Model. Further improvements in precision are possible if the ft values for pairs of mirror 0+ -->0+ transitions can be measured with 0.1% precision or better. The decays of 34Ar and 34Cl are members of such a mirror pair, but so far the former is not known with sufficient precision. Since our 2006 publication of the half-life of 34Ar, we have improved significantly our acquisition and analysis techniques, adding refinements that have led to increased accuracy. The 34Cl half-life is about twice that of 34Ar. This obscures the 34A