121 research outputs found

    Evaluation of DSS-14 pedestal-review of top surface repair procedures

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    Proposed repair procedures for the top surface of the pedestal supporting the hydrostatic bearing runner for the 64m Antenna are presented. These procedures included: (1) removal of existing grout and concrete to approximately 8 in. below original concrete surface using a presplitting technique with expansive cement followed by secondary breaking; (2) preparation of exposed concrete surface including an epoxy bonding agent; and (3) replacement of material removed with 8 in. of new concrete surface including an epoxy bonding agent; and (4) replacement of material removed with 8 in. of new concrete and 4 in. of new grout

    Seasonal effect and long-term nutritional status following exit from a Community-Based Management of Severe Acute Malnutrition program in Bihar, India.

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    BACKGROUND/OBJECTIVES: Children aged 6 months to 5 years completing treatment for severe acute malnutrition (SAM) in a Médecins Sans Frontières Community Management of Acute Malnutrition (CMAM) program in Bihar, India, showed high cure rates; however, the program suffered default rates of 38%. This report describes the nutritional status of 1956 children followed up between 3 and 18 months after exiting the program. SUBJECTS/METHODS: All children aged 6-59 months discharged as cured with mid-upper arm circumference (MUAC) ⩾120 mm or who defaulted from the program with MUAC <115 mm were traced at 3, 6, 9, 12 and 18 months (±10 days) before three exit reference dates: first at the end of the food insecure period, second after the 2-month food security and third after the 4-month food security. RESULTS: Overall, 68.7% (n=692) of defaulters and 76.2% (n=1264) of children discharged as cured were traced. Combined rates of non-recovery in children who defaulted with MUAC <115 mm were 41%, 30.1%, 9.9%, 6.1% and 3.6% at 3, 6, 9, 12 and 18 months following exit, respectively. Combined rates of relapse among cured cases (MUAC ⩾120 mm) were 9.1%, 2.9%, 2.1%, 2.8% and 0% at 3, 6, 9, 12 and 18 months following discharge, respectively. Prevalence of undernutrition increased substantially for both groups traced during low food security periods. Odds of death were much higher for children defaulting with MUAC <110 mm when compared with children discharged as cured, who shared the same mortality risk as those defaulting with MUAC 110-<115 mm. CONCLUSIONS: Seasonal food security predicted short-term nutritional status after exit, with relapse rates and non-recovery from SAM much higher during food insecurity. Mortality outcomes suggest that a MUAC of 110 mm may be considered an appropriate admission point for SAM treatment programs in this context

    Deciphering the genome structure and paleohistory of _Theobroma cacao_

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    We sequenced and assembled the genome of _Theobroma cacao_, an economically important tropical fruit tree crop that is the source of chocolate. The assembly corresponds to 76% of the estimated genome size and contains almost all previously described genes, with 82% of them anchored on the 10 _T. cacao_ chromosomes. Analysis of this sequence information highlighted specific expansion of some gene families during evolution, for example flavonoid-related genes. It also provides a major source of candidate genes for _T. cacao_ disease resistance and quality improvement. Based on the inferred paleohistory of the T. cacao genome, we propose an evolutionary scenario whereby the ten _T. cacao_ chromosomes were shaped from an ancestor through eleven chromosome fusions. The _T. cacao_ genome can be considered as a simple living relic of higher plant evolution

    Characterization of the major fragance gene from an aromatic japonica rice and analysis of its diversity in Asian cultivated rice

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    In Asian cultivated rice (Oryza sativa L.), aroma is one of the most valuable traits in grain quality and 2-ACP is the main volatile compound contributing to the characteristic popcorn-like odour of aromatic rices. Although the major locus for grain fragrance (frg gene) has been described recently in Basmati rice, this gene has not been characterised in true japonica varieties and molecular information available on the genetic diversity and evolutionary origin of this gene among the different varieties is still limited. Here we report on characterisation of the frg gene in the Azucena variety, one of the few aromatic japonica cultivars. We used a RIL population from a cross between Azucena and IR64, a non-aromatic indica, the reference genomic sequence of Nipponbare (japonica) and 93–11 (indica) as well as an Azucena BAC library, to identify the major fragance gene in Azucena. We thus identified a betaine aldehyde dehydrogenase gene, badh2, as the candidate locus responsible for aroma, which presented exactly the same mutation as that identified in Basmati and Jasmine-like rices. Comparative genomic analyses showed very high sequence conservation between Azucena and Nipponbare BADH2, and a MITE was identified in the promotor region of the BADH2 allele in 93–11. The badh2 mutation and MITE were surveyed in a representative rice collection, including traditional aromatic and non-aromatic rice varieties, and strongly suggested a monophylogenetic origin of this badh2 mutation in Asian cultivated rices. Altogether these new data are discussed here in the light of current hypotheses on the origin of rice genetic diversity

    Specific patterns of gene space organisation revealed in wheat by using the combination of barley and wheat genomic resources

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    <p>Abstract</p> <p>Background</p> <p>Because of its size, allohexaploid nature and high repeat content, the wheat genome has always been perceived as too complex for efficient molecular studies. We recently constructed the first physical map of a wheat chromosome (3B). However gene mapping is still laborious in wheat because of high redundancy between the three homoeologous genomes. In contrast, in the closely related diploid species, barley, numerous gene-based markers have been developed. This study aims at combining the unique genomic resources developed in wheat and barley to decipher the organisation of gene space on wheat chromosome 3B.</p> <p>Results</p> <p>Three dimensional pools of the minimal tiling path of wheat chromosome 3B physical map were hybridised to a barley Agilent 15K expression microarray. This led to the fine mapping of 738 barley orthologous genes on wheat chromosome 3B. In addition, comparative analyses revealed that 68% of the genes identified were syntenic between the wheat chromosome 3B and barley chromosome 3 H and 59% between wheat chromosome 3B and rice chromosome 1, together with some wheat-specific rearrangements. Finally, it indicated an increasing gradient of gene density from the centromere to the telomeres positively correlated with the number of genes clustered in islands on wheat chromosome 3B.</p> <p>Conclusion</p> <p>Our study shows that novel structural genomics resources now available in wheat and barley can be combined efficiently to overcome specific problems of genetic anchoring of physical contigs in wheat and to perform high-resolution comparative analyses with rice for deciphering the organisation of the wheat gene space.</p

    Saturation of an Intra-Gene Pool Linkage Map: Towards a Unified Consensus Linkage Map for Fine Mapping and Synteny Analysis in Common Bean

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    Map-based cloning and fine mapping to find genes of interest and marker assisted selection (MAS) requires good genetic maps with reproducible markers. In this study, we saturated the linkage map of the intra-gene pool population of common bean DOR364×BAT477 (DB) by evaluating 2,706 molecular markers including SSR, SNP, and gene-based markers. On average the polymorphism rate was 7.7% due to the narrow genetic base between the parents. The DB linkage map consisted of 291 markers with a total map length of 1,788 cM. A consensus map was built using the core mapping populations derived from inter-gene pool crosses: DOR364×G19833 (DG) and BAT93×JALO EEP558 (BJ). The consensus map consisted of a total of 1,010 markers mapped, with a total map length of 2,041 cM across 11 linkage groups. On average, each linkage group on the consensus map contained 91 markers of which 83% were single copy markers. Finally, a synteny analysis was carried out using our highly saturated consensus maps compared with the soybean pseudo-chromosome assembly. A total of 772 marker sequences were compared with the soybean genome. A total of 44 syntenic blocks were identified. The linkage group Pv6 presented the most diverse pattern of synteny with seven syntenic blocks, and Pv9 showed the most consistent relations with soybean with just two syntenic blocks. Additionally, a co-linear analysis using common bean transcript map information against soybean coding sequences (CDS) revealed the relationship with 787 soybean genes. The common bean consensus map has allowed us to map a larger number of markers, to obtain a more complete coverage of the common bean genome. Our results, combined with synteny relationships provide tools to increase marker density in selected genomic regions to identify closely linked polymorphic markers for indirect selection, fine mapping or for positional cloning

    Sequencing of diverse mandarin, pummelo and orange genomes reveals complex history of admixture during citrus domestication

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    Cultivated citrus are selections from, or hybrids of, wild progenitor species whose identities and contributions to citrus domestication remain controversial. Here we sequence and compare citrus genomes-a high-quality reference haploid clementine genome and mandarin, pummelo, sweet-orange and sour-orange genomes-and show that cultivated types derive from two progenitor species. Although cultivated pummelos represent selections from one progenitor species, Citrus maxima, cultivated mandarins are introgressions of C. maxima into the ancestral mandarin species Citrus reticulata. The most widely cultivated citrus, sweet orange, is the offspring of previously admixed individuals, but sour orange is an F1 hybrid of pure C. maxima and C. reticulata parents, thus implying that wild mandarins were part of the early breeding germplasm. A Chinese wild 'mandarin' diverges substantially from C. reticulata, thus suggesting the possibility of other unrecognized wild citrus species. Understanding citrus phylogeny through genome analysis clarifies taxonomic relationships and facilitates sequence-directed genetic improvement. (Résumé d'auteur

    Dynamic modelling of ammonia biofiltration from waste gases

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    A dynamic model to describe ammonia removal in a gas-phase biofilter was developed. The math-ematical model is based on discretized mass balances and detailed nitrification kinetics that includeinhibitory effects caused by free ammonia (FA) and free nitrous acid (FNA). The model was able to pre-dict experimental results operation under different loading rates (from 3.2 to 13.2 g NH3h-1m-3). In par-ticular the model was capable of reproducing inhibition caused by high inlet ammonia concentrations. Alsoelimination capacity was accurately predicted. Experimental data was also used to optimize certain modelparameters such as the concentration of ammonia- and nitrite-oxidizing biomass.Peer ReviewedPostprint (published version
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