461 research outputs found

    Use of recycled Aluminium for low cost production of metallic foams

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    Los metales celulares (MC) son materiales innovadores con muy baja densidad que se caracterizan por poseer una atractiva combinación de propiedades mecánicas y físicas, lo que los convierte en potenciales candidatos para una amplia gama de aplicaciones en diversos sectores como el automotriz, aeronaútico, construcción, implantes biomédicos, entre otros. Sin embargo, una desventaja inherente a éste tipo de materiales está dada por su alto costo, el cual básicamente rádica en los procesos existentes para la producción de metales celulares. Con el fn de obtener espumas de aluminio de porosidad abierta y a un bajo costo, se realizó el presente estudio basado en la selección de un proceso de producción económico aunado al uso de materias de bajo costo (aluminio reciclado) y de fácil consecución (sal comercial). Una vez obtenidas las espumas de poro abierto, su calidad se validó mediante la evaluación de los aspectos estructurales y microestructurales. Además, fueron evaluadas las propiedades de absorción de sonido y la resistencia a la compresión. Los resultados demostraron que el proceso propuesto fue exitoso, ya que las espumas de aluminio reciclado obtenidas presentaron propiedades físicas y mecánicas comparativas con las reportadas en la literatura para otros MC.Abstract: Cellular metals are innovative materials with very low density characterized by their very atractive combination of mechanical and physical properties, it makes them potential candidates for a wide range of applications in several sectors such as: the automotive, aeronautical, construction, biomedical implants, etc. However, an inherent drawback of this kind of materials is given by their high cost, which is basically due to the production process used to produce cellular metals. In order to obtain aluminium foams with open porosity , the present work based in the selection of an economical production process together with the use of low price raw materials (recycled aluminium) and easy consecution (commercial salt), was done. The obtained aluminum foams quality was validated by mean the evaluation of structural and microstructural aspects. Moreover, sound absorption and compression strength properties were evaluated. The results showed that the process was satisfactory since the mechanical and physical properties exhibited by the obtained recycled aluminum foams were comparatives with other MC reported in the literature

    Effect of gamma radiation of 60Co on sunflower plants (Helianthus annuus L.) (Asteraceae), from irradiated achenes

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    In order to know the effect of 60Co gamma irradiation, in the sunflower crop, were irradiated achenes in the Transelektro LGI-01 in the Instituto Nacional de Investigaciones Nucleares. The data was evaluated under a completely randomized design, where the treatments were 0, 100, 200, 300, 400, 500, 600, 700, 800 and 900 Gy and four repetitions (10x4) = 40 experimental units. The response variables were: plant height, root length and volume, dry biomass. The results indicated that germination and sprouting decreased as the radiation increased, adjusting these to a quadratic model. Plant height, length, root volume and dry biomass decreased at high doses. From this investigation it was concluded, that doses of 100 and 200 Gy, have a stimulating effect on plant height and root length, being an important agent, to induce genetic variability in sunflower

    Design Specifications for an Auxiliary Incision Retractor in Dacryocystorhinostomy Surgeries

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    It is presented the design specifications for a Retractor Robotic System (RRS) based on the surgical necessities in the incisions procedure for a dacryocystorhinostomy. The specifications are conformed by a mathematical model, the experimental data measured, a modular flexible architecture, energy supplier system, the mechanical group, and the safety system. The specifications suggest that the use of flexible polymeric materials for the RRS provide a mayor adaptability of the system with the biological tissue; so a pneumatic actuator could be a suitable option.This research was funded by CONACYT (Consejo Nacional de Ciencia y Tecnología) Grant No. 86356

    Indicadores de qualidade do solo em sistemas de cultivo orgânico e convencional no semi-árido Cearense.

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    A qualidade do solo pode mudar com o passar do tempo, em decorrência de eventos naturais ou ações antrópicas. A adoção de práticas de cultivo orgânico reduz o revolvimento do solo, favorecendo a recuperação de suas propriedades físicas e químicas. Este trabalho teve como objetivo comparar propriedades físicas,químicas e biológicas de solos cultivados com algodão em bases orgânicas e no sistema convencional, assim como identificar as que possam ser utilizadas como indicadores de qualidade do solo. Selecionaram-se seis áreas submetidas ao cultivo orgânico e três ao cultivo convencional para coleta de amostras de solo deformadas e indeformadas, nas camadas de 0–10, 10–20 e 20–30 cm. Técnicas de estatística univariada e multivariada foram utilizadas para análise dos dados. Os resultados mostraram que os indicadores físicos e químicos testados individualmente não foram sensíveis para diferenciar as áreas sob sistema de cultivo orgânico daquelas sob cultivo convencional. No entanto, a aplicação de técnicas de análise multivariada – no caso, componentes principais e a discriminante de Anderson – permitiu a distinção entre algumas áreas cultivadas sob cultivo orgânico comparativamente às convencionais, até mesmo as que estavam em transição.Dos indicadores biológicos, a fauna edáfica mostrou-se mais precisa na avaliação da qualidade do solo, distinguindo de forma satisfatória as áreas sob sistema de cultivo orgânico das que estavam sob sistema convencional

    Climate‐driven spatial and temporal patterns in peatland pool biogeochemistry

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    Peatland pools are freshwater bodies that are highly dynamic aquatic ecosystems because of their small size and their development in organic-rich sediments. However, our ability to understand and predict their contribution to both local and global biogeochemical cycles under rapidly occurring environmental change is limited because the spatiotemporal drivers of their biogeochemical patterns and processes are poorly understood. We used (1) pool biogeochemical data from 20 peatlands in eastern Canada, the United Kingdom, and southern Patagonia and (2) multi-year data from an undisturbed peatland of eastern Canada, to determine how climate and terrain features drive the production, delivering and processing of carbon (C), nitrogen (N), and phosphorus (P) in peatland pools. Across sites, climate (24%) and terrain (13%) explained distinct portions of the variation in pool biogeochemistry, with climate driving spatial differences in pool dissolved organic C (DOC) concentration and aromaticity. Within the multi-year dataset, DOC, carbon dioxide (CO2), total N concentrations, and DOC aromaticity were highest in the shallowest pools and at the end of the growing seasons, and increased gradually from 2016 to 2021 in relation to a combination of increases in summer precipitation, mean air temperature for the previous fall, and number of extreme summer heat days. Given the contrasting effects of terrain and climate, broad-scale terrain characteristics may offer a baseline for the prediction of small-scale pool biogeochemistry, while broad-scale climate gradients and relatively small year-to-year variations in local climate induce a noticeable response in pool biogeochemistry. These findings emphasize the reactivity of peatland pools to both local and global environmental change and highlight their potential to act as widely distributed climate sentinels within historically relatively stable peatland ecosystems

    Building The Sugarcane Genome For Biotechnology And Identifying Evolutionary Trends

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    Background: Sugarcane is the source of sugar in all tropical and subtropical countries and is becoming increasingly important for bio-based fuels. However, its large (10 Gb), polyploid, complex genome has hindered genome based breeding efforts. Here we release the largest and most diverse set of sugarcane genome sequences to date, as part of an on-going initiative to provide a sugarcane genomic information resource, with the ultimate goal of producing a gold standard genome.Results: Three hundred and seventeen chiefly euchromatic BACs were sequenced. A reference set of one thousand four hundred manually-annotated protein-coding genes was generated. A small RNA collection and a RNA-seq library were used to explore expression patterns and the sRNA landscape. In the sucrose and starch metabolism pathway, 16 non-redundant enzyme-encoding genes were identified. One of the sucrose pathway genes, sucrose-6-phosphate phosphohydrolase, is duplicated in sugarcane and sorghum, but not in rice and maize. A diversity analysis of the s6pp duplication region revealed haplotype-structured sequence composition. Examination of hom(e)ologous loci indicate both sequence structural and sRNA landscape variation. A synteny analysis shows that the sugarcane genome has expanded relative to the sorghum genome, largely due to the presence of transposable elements and uncharacterized intergenic and intronic sequences.Conclusion: This release of sugarcane genomic sequences will advance our understanding of sugarcane genetics and contribute to the development of molecular tools for breeding purposes and gene discovery. © 2014 de Setta et al.; licensee BioMed Central Ltd.151European Commission: Agriculture and Rural Development: Sugar http://ec.europa.eu/agriculture/sugar/index_en.htmKellogg, E.A., Evolutionary history of the grasses (2001) Plant Physiol, 125, pp. 1198-1205Grivet, L., Arruda, P., Sugarcane genomics: depicting the complex genome of an important tropical crop (2001) Curr Opin Plant Biol, 5, pp. 122-127Piperidis, G., Piperidis, N., D'Hont, A., Molecular cytogenetic investigation of chromosome composition and transmission in sugarcane (2010) Mol Genet Genomics, 284, pp. 65-73D'Hont, A., Unraveling the genome structure of polyploids using FISH and GISHexamples of sugarcane and banana (2005) Cytogenet Genome Res, 109, pp. 27-33D'Hont, A., Glaszmann, J.C., Sugarcane genome analysis with molecular markers: a first decade of research (2001) Int Soc Sugar Cane Technol Proc XXIV Congr, pp. 556-559Tomkins, J., Yu, Y., Miller-Smith, H., Frisch, D., Woo, S., Wing, R., A bacterial artificial chromosome library for sugarcane (1999) Theor Appl Genet, 99, pp. 419-424Vettore, L., Silva, F.R., Kemper, E.L., Souza, G.M., Silva, A.M., Ferro, M., Henrique-Silva, F., Monteiro-Vitorello, C.B., Analysis and functional annotation of an expressed sequence tag collection for tropical crop sugarcane (2003) Genome Res, 13, pp. 2725-2735Repbase http://www.girinst.org/repbase/Domingues, D.S., Cruz, G.M.Q., Metcalfe, C.J., Nogueira, F.T.S., Vicentini, R., Alves, C.S., Van Sluys, M.-A., Analysis of plant LTR-retrotransposons at the fine-scale family level reveals individual molecular patterns (2012) BMC Genomics, 13, p. 137National Center for Biotechnology Information (NCBI) http://www.ncbi.nlm.nih.gov/Meyer, F., Paarmann, D., D'Souza, M., Olson, R., Glass, E.M., Kubal, M., Paczian, T., Edwards, R.A., The metagenomics RAST server - a public resource for the automatic phylogenetic and functional analysis of metagenomes (2008) BMC Bioinformatics, 9, p. 386Keeling, P.L., Myers, A.M., Biochemistry and genetics of starch synthesis (2010) Annu Rev Food Sci Technol, 1, pp. 271-303Phytozome v9.1: Home http://www.phytozome.net/Dias, E.S., Carareto, C.M.A., Ancestral polymorphism and recent invasion of transposable elements in Drosophila species (2012) BMC Evol Biol, 12, p. 119Posada, D., Crandall, K., Intraspecific gene genealogies: trees grafting into networks (2001) Trends Ecol Evol, 16, pp. 37-45Swaminathan, K., Alabady, M.S., Varala, K., De Paoli, E., Ho, I., Rokhsar, D.S., Arumuganathan, A.K., Hudson, M.E., Genomic and small RNA sequencing of Miscanthus x giganteus shows the utility of sorghum as a reference genome sequence for Andropogoneae grasses (2010) Genome Biol, 11, pp. R12Zanca, A.S., Vicentini, R., Ortiz-Morea, F.A., Del Bem, L.E., da Silva, M.J., Vincentz, M., Nogueira, F.T., Identification and expression analysis of microRNAs and targets in the biofuel crop sugarcane (2010) BMC Plant Biol, 10, p. 260Piriyapongsa, J., Jordan, I.K., A family of human microRNA genes from miniature inverted-repeat transposable elements (2007) PLoS ONE, 2, pp. e203Barrera-Figueroa, B.E., Gao, L., Wu, Z., Zhou, X., Zhu, J., Jin, H., Liu, R., Zhu, J.-K., High throughput sequencing reveals novel and abiotic stress-regulated microRNAs in the inflorescences of rice (2012) BMC Plant Biol, 12, p. 132Nagaki, K., Tsujimoto, H., Sasakuma, T., A novel repetitive sequence of sugar cane, SCEN family, locating on centromeric regions (1998) Chromosom Res, 6, pp. 295-302Nagaki, K., Neumann, P., Zhang, D., Ouyang, S., Buell, C.R., Cheng, Z., Jiang, J., Structure, divergence, and distribution of the CRR centromeric retrotransposon family in rice (2005) Mol Biol Evol, 22, pp. 845-855Vicentini, R., Del Bem, L.E., Van Sluys, M.-A., Nogueira, F., Vincentz, M., Gene content analysis of sugarcane public ESTs reveals thousands of missing coding-genes and an unexpected pool of grasses conserved ncRNAs (2012) Trop Plant Biol, 5, pp. 199-205Kim, C., Lee, T.-H., Compton, R.O., Robertson, J.S., Pierce, G.J., Paterson, A.H., A genome-wide BAC end-sequence survey of sugarcane elucidates genome composition, and identifies BACs covering much of the euchromatin (2013) Plant Mol Biol, 81, pp. 139-147Paterson, A.H., Bowers, J.E., Bruggmann, R., Dubchak, I., Grimwood, J., Gundlach, H., Haberer, G., Carpita, N.C., The Sorghum bicolor genome and the diversification of grasses (2009) Nature, 457, pp. 551-556Chang, Y., Gong, L., Yuan, W., Li, X., Chen, G., Li, X., Zhang, Q., Wu, C., Replication protein A (RPA1a) is required for meiotic and somatic DNA repair but is dispensable for DNA replication and homologous recombination in rice (2009) Plant Physiol, 151, pp. 2162-2173Feschotte, C., Transposable elements and the evolution of regulatory networks (2008) Nat Rev Genet, 9, pp. 397-405Wang, J., Roe, B., Macmil, S., Yu, Q., Murray, J.E., Tang, H., Chen, C., Ming, R., Microcollinearity between autopolyploid sugarcane and diploid sorghum genomes (2010) BMC Genomics, 11, p. 261Garsmeur, O., Charron, C., Bocs, S., Jouffe, V., Samain, S., Couloux, A., Droc, G., D'Hont, A., High homologous gene conservation despite extreme autopolyploid redundancy in sugarcane (2011) New Phytol, 189, pp. 629-642Jannoo, N., Grivet, L., Chantret, N., Garsmeur, O., Glaszmann, J.C., Arruda, P., D'Hont, A., Orthologous comparison in a gene-rich region among grasses reveals stability in the sugarcane polyploid genome (2007) Plant J, 50, pp. 574-585Figueira, T.R.E.S., Okura, V., da Silva, F.R., da Silva, M.J., Kudrna, D., Ammiraju, J.S.S., Talag, J., Arruda, P., A BAC library of the SP80-3280 sugarcane variety (saccharum sp.) and its inferred microsynteny with the sorghum genome (2012) BMC Res Notes, 5, p. 185Schnable, P.S., Ware, D., Fulton, R.S., Stein, J.C., Wei, F., Pasternak, S., Liang, C., Gillam, B., The B73 maize genome: complexity, diversity, and dynamics (2009) Science, 326, pp. 1112-1115Tenaillon, M.I., Hufford, M.B., Gaut, B.S., Ross-Ibarra, J., Genome size and transposable element content as determined by high-throughput sequencing in maize and Zea luxurians (2011) Genome Biol Evol, 3, pp. 219-229Zhang, J., Yu, C., Krishnaswamy, L., Peterson, T., Transposable Elements as Catalysts for Chromosome Rearrangements (2011) Methods Mol Biol, pp. 315-326. , Totowa, NJ: Humana Press, Birchler JAMa, J., Wing, R.A., Bennetzen, J.L., Jackson, S.A., Plant centromere organization: a dynamic structure with conserved functions (2007) Trends Genet, 23, pp. 134-139D'Hont, A., Grivet, L., Feldmann, P., Rao, S., Berding, N., Glaszmann, J.C., Characterisation of the double genome structure of modern sugarcane cultivars (Saccharum spp.) by molecular cytogenetics (1996) Mol Gen Genet, 250, pp. 405-413Bao, Y., Wendel, J.F., Ge, S., Multiple patterns of rDNA evolution following polyploidy in Oryza (2010) Mol Phylogenet Evol, 55, pp. 136-142Lynch, M., (2007) The Origins of Genome Architecture, , Sunderland, Massachussetts, USA: Sinauer Associates IncThe map-based sequence of the rice genome (2005) Nature, 436, pp. 793-800. , International Rice Genome Sequencing ProjectLiu, B., Xu, C., Zhao, N., Qi, B., Kimatu, J.N., Pang, J., Han, F., Rapid genomic changes in polyploid wheat and related species: implications for genome evolution and genetic improvement (2009) J Genet Genomics, 36, pp. 519-528Lisch, D., How important are transposons for plant evolution? (2012) Nat Rev Genet, 14, pp. 49-61Udall, J.A., Wendel, J.F., Polyploidy and crop improvement (2006) Crop Sci, 46, pp. S3-S14Varshney, R.K., Graner, A., Sorrells, M.E., Genomics-assisted breeding for crop improvement (2005) Trends Plant Sci, 10, pp. 621-630Menossi, M., Silva-Filho, M.C., Vincentz, M., Van-Sluys, M.-A., Souza, G.M., Sugarcane functional genomics: gene discovery for agronomic trait development (2008) Int J Plant Genomics, 2008, p. 458732. , doi:10.1155/2008/458732Palhares, A.C., Rodrigues-Morais, T.B., Van Sluys, M.-A., Domingues, D.S., Maccheroni, W., Jordão, H., Souza, A.P., Vieira, M.L.C., A novel linkage map of sugarcane with evidence for clustering of retrotransposon-based markers (2012) BMC Genet, 13, p. 51Andersen, J.R., Lübberstedt, T., Functional markers in plants (2003) Trends Plant Sci, 8, pp. 554-560Kalendar, R., Flavell, A.J., Ellis, T.H.N., Sjakste, T., Moisy, C., Schulman, A., Analysis of plant diversity with retrotransposon-based molecular markers (2011) Heredity (Edinb), 106, pp. 520-530PGML BACMan On The Web: Grasses http://www.plantgenome.uga.edu/bacman/BACManwww.phpRice Genome Annotation Project http://rice.plantbiology.msu.edu/Bowers, J.E., Arias, M.A., Asher, R., Avise, J.A., Ball, R.T., Brewer, G.A., Buss, R.W., Soderlund, C.A., Comparative physical mapping links conservation of microsynteny to chromosome structure and recombination in grasses (2005) Proc Natl Acad Sci U S A, 102, pp. 13206-13211Adam-Blondon, A.-F., Bernole, A., Faes, G., Lamoureux, D., Pateyron, S., Grando, M.S., Caboche, M., Chalhoub, B., Construction and characterization of BAC libraries from major grapevine cultivars (2005) Theor Appl Genet, 110, pp. 1363-1371Manetti, M.E., Rossi, M., Cruz, G.M.Q., Saccaro, N.L., Nakabashi, M., Altebarmakian, V., Rodier-Goud, M., Van Sluys, M.A., Mutator system derivatives isolated from sugarcane genome sequence (2012) Trop Plant Biol, 5, pp. 233-243Phrap http://www.phrap.org/RepeatMasker http://www.repeatmasker.org/Jurka, J., Kapitonov, V.V., Pavlicek, A., Klonowski, P., Kohany, O., Repbase update, a database of eukaryotic repetitive elements (2005) Cytogenet Genome Res, 110, pp. 462-467Han, Y., Wessler, S.R., MITE-Hunter: a program for discovering miniature inverted-repeat transposable elements from genomic sequences (2010) Nucleic Acids Res, 38 (22), pp. e199. , doi: 10.1093/nar/gkq862. Epub 2010 Sep 29Frickey, T., Lupas, A., CLANS: a Java application for visualizing protein families based on pairwise similarity (2004) Bioinformatics, 20, pp. 3702-3704Han, Y., Qin, S., Wessler, S.R., Comparison of class 2 transposable elements at superfamily resolution reveals conserved and distinct features in cereal grass genomes (2013) BMC Genomics, 14, p. 71Keller, O., Kollmar, M., Stanke, M., Waack, S., A novel hybrid gene prediction method employing protein multiple sequence alignments (2011) Bioinformatics, 27, pp. 757-763Majoros, W.H., Pertea, M., Salzberg, S.L., TigrScan and GlimmerHMM: two open source ab initio eukaryotic gene-finders (2004) Bioinformatics, 20, pp. 2878-2879Haas, B.J., Delcher, A.L., Mount, S.M., Wortman, J.R., Smith, R.K., Hannick, L.I., Maiti, R., White, O., Improving the Arabidopsis genome annotation using maximal transcript alignment assemblies (2003) Nucleic Acids Res, 31, pp. 5654-5666Haas, B.J., Salzberg, S.L., Zhu, W., Pertea, M., Allen, J.E., Orvis, J., White, O., Wortman, J.R., Automated eukaryotic gene structure annotation using EVidenceModeler and the Program to assemble spliced alignments (2008) Genome Biol, 9, pp. R7Petersen, T.N., Brunak, S., von Heijne, G., Nielsen, H., SignalP 4.0: discriminating signal peptides from transmembrane regions (2011) Nat Methods, 8, pp. 785-786TMHMM Server v. 2.0 http://www.cbs.dtu.dk/services/TMHMM-2.0/Rutherford, K., Parkhill, J., Crook, J., Horsnell, T., Rice, P., Rajandream, M.A., Barrell, B., Artemis: sequence visualization and annotation (2000) Bioinformatics, 16, pp. 944-945UniProt http://www.uniprot.org/InterPro: Protein sequence analysis and classification http://www.ebi.ac.uk/interpro/Conesa, A., Götz, S., Blast2GO: a comprehensive suite for functional analysis in plant genomics (2008) Int J Plant Genomics, 2008, pp. 1-12SUCEST-FUN Project http://sucest-fun.org/MG-RAST: metagenomics analysis server http://metagenomics.anl.gov/KAAS - KEGG automatic annotation server http://www.genome.jp/kegg/kaas/Tamura, K., Peterson, D., Peterson, N., Stecher, G., Nei, M., Kumar, S., MEGA5: molecular evolutionary genetics analysis using maximum likelihood, evolutionary distance, and maximum parsimony methods (2011) Mol Biol Evol, 28, pp. 2731-2739Lyons, E., Freeling, M., How to usefully compare homologous plant genes and chromosomes as DNA sequences (2008) Plant J, 53, pp. 661-673Hall, T.A., BioEdit: a user-friendly biological sequence alignment editor and analysis program for Windows 95/98/NT (1999) Nucleic Acids Symp Ser, 41, pp. 95-98Geneious - Homepage http://www.geneious.com/Heslop-Harrison, P., Schwarzacher, T., (2000) Practical In Situ Hybridization, , Oxford, UK: BIOS Scientific Publishers LtdAljanabi, S., Forget, L., Dookun, A., An improved and rapid protocol for the isolation of polysaccharide-and polyphenol-free sugarcane DNA (1999) Plant Mol Biol Report, 17, pp. 1-8Maq: Mapping and assembly with qualities http://maq.sourceforge.net/SeqMonk http://www.bioinformatics.babraham.ac.uk/projects/seqmonk/Gasic, K., Hernandez, A., Korban, S.S., RNA extraction from different apple tissues rich in polyphenols and polysaccharides for cDNA (2004) Plant Mol Biol Report, 22 (DECEMBER), pp. 437a-437gLi, H., Durbin, R., Fast and accurate short read alignment with Burrows-Wheeler transform (2009) Bioinformatics, 25, pp. 1754-1760Li, H., Handsaker, B., Wysoker, A., Fennell, T., Ruan, J., Homer, N., Marth, G., Durbin, R., The sequence Alignment/Map format and SAMtools (2009) Bioinformatics, 25, pp. 2078-2079Thompson, J.D., Higgins, D.G., Gibson, T.J., CLUSTAL W: improving the sensitivity of progressive multiple sequence alignment through sequence weighting, position-specific gap penalties and weight matrix choice (1994) Nucleic Acids Res, 22, pp. 4673-4680Bandelt, H.J., Forster, P., Röhl, A., Median-joining networks for inferring intraspecific phylogenies (1999) Mol Biol Evol, 16, pp. 37-48Paterson, A.H., Freeling, M., Tang, H., Wang, X., Insights from the comparison of plant genome sequences (2010) Annu Rev Plant Biol, 61, pp. 349-37

    Grain Surface Models and Data for Astrochemistry

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    AbstractThe cross-disciplinary field of astrochemistry exists to understand the formation, destruction, and survival of molecules in astrophysical environments. Molecules in space are synthesized via a large variety of gas-phase reactions, and reactions on dust-grain surfaces, where the surface acts as a catalyst. A broad consensus has been reached in the astrochemistry community on how to suitably treat gas-phase processes in models, and also on how to present the necessary reaction data in databases; however, no such consensus has yet been reached for grain-surface processes. A team of ∼25 experts covering observational, laboratory and theoretical (astro)chemistry met in summer of 2014 at the Lorentz Center in Leiden with the aim to provide solutions for this problem and to review the current state-of-the-art of grain surface models, both in terms of technical implementation into models as well as the most up-to-date information available from experiments and chemical computations. This review builds on the results of this workshop and gives an outlook for future directions

    Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

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    This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

    Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

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    The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter
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