715 research outputs found

    Predictability of the quasi-biennial oscillation and its northern winter teleconnection on seasonal to decadal timescales

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    Journal ArticlePublished version used with permision of the publisher.The predictability of the quasi-biennial oscillation (QBO) is examined in initialized climate forecasts extending out to lead times of years. We use initialized retrospective predictions made with coupled ocean-atmosphere climate models that have an internally generated QBO. We demonstrate predictability of the QBO extending more than 3 years into the future, well beyond timescales normally associated with internal atmospheric processes. Correlation scores with observational analyses exceed 0.7 at a lead time of 12 months. We also examine the variation of predictability with season and QBO phase and find that skill is lowest in winter. An assessment of perfect predictability suggests that higher skill may be achievable through improved initialization and climate modeling of the QBO, although this may depend on the realism of gravity wave source parameterizations in the models. Finally, we show that skilful prediction of the QBO itself does not guarantee predictability of the extratropical winter teleconnection that is important for surface winter climate prediction. Key Points The QBO is skilfully predicted in seasonal-decadal forecast systems Further improvements in predictions of the QBO are possible The QBO winter surface teleconnection is reproduced with mixed succes

    HaploReg: a resource for exploring chromatin states, conservation, and regulatory motif alterations within sets of genetically linked variants

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    The resolution of genome-wide association studies (GWAS) is limited by the linkage disequilibrium (LD) structure of the population being studied. Selecting the most likely causal variants within an LD block is relatively straightforward within coding sequence, but is more difficult when all variants are intergenic. Predicting functional non-coding sequence has been recently facilitated by the availability of conservation and epigenomic information. We present HaploReg, a tool for exploring annotations of the non-coding genome among the results of published GWAS or novel sets of variants. Using LD information from the 1000 Genomes Project, linked SNPs and small indels can be visualized along with their predicted chromatin state in nine cell types, conservation across mammals and their effect on regulatory motifs. Sets of SNPs, such as those resulting from GWAS, are analyzed for an enrichment of cell type-specific enhancers. HaploReg will be useful to researchers developing mechanistic hypotheses of the impact of non-coding variants on clinical phenotypes and normal variation. The HaploReg database is available at http://compbio.mit.edu/HaploReg.National Institutes of Health (U.S.) (R01-HG004037)National Institutes of Health (U.S.) (RC1-HG005334)National Science Foundation (U.S.) (HG005334

    Sistema sulco/camalhĆ£o para irrigaĆ§Ć£o e drenagem em Ć”reas de vĆ”rzea.

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    SISTEMA SULCO/CAMALHƃO PARA IRRIGAƇƃO E DRENAGEM EM ƁREAS DE VƁRZEA - A soja e o milho sĆ£o as principais culturas produtoras de grĆ£os utilizadas na diversificaĆ§Ć£o do sistema de produĆ§Ć£o nas vĆ”rzeas do Rio Grande do Sul, em rotaĆ§Ć£o com o arroz irrigado. Os principais fatores limitantes, para que estas culturas sejam produtivas e rentĆ”veis neste sistema, sĆ£o a deficiente drenagem natural do solo e a ocorrĆŖncia de freqĆ¼entes perĆ­odos de estiagem, acarretando alternĆ¢ncia entre o excesso e o dĆ©ficit de umidade no solo. A Embrapa Clima Temperado testou e validou a tĆ©cnica sulco/camalhĆ£o em Ć”reas sistematizadas com e sem declive, para estes cultivos, com resultados bastante promissores. O sistema consiste na estruturaĆ§Ć£o da lavoura para a irrigaĆ§Ć£o por sulcos, obtendo-se, ao mesmo tempo, grande benefĆ­cio em drenagem, com o cultivo sobre os camalhƵes formados entre os sulcos. Esta tĆ©cnica, como sistema complementar de drenagem superficial do solo, mostrou-se muito eficiente mesmo nos cultivos em Ć”reas sistematizadas sem declive, onde nĆ£o existe um gradiente para escoamento superficial da Ć”gua. O principal requisito para a irrigaĆ§Ć£o por sulcos Ć© que o terreno tenha uma declividade constante e uniforme, requerendo geralmente a sistematizaĆ§Ć£o do terreno. Para irrigaƧƵes mais uniformes e eficientes, a declividade deve variar de 0,10% a 0,50%, sendo que valores intermediĆ”rios entre 0,15% e 0,30% sĆ£o os mais indicadosbitstream/item/31294/1/comunicado-165.pd

    The Migration of Elites in a Borderless World: Citizenship as an Incentive for Professionals and Managers?

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    Der Artikel geht der Frage nach, inwiefern die geƶffneten TĆ¼ren fĆ¼r die Immigration Hochqualifizierter in den OECD-LƤndern tatsƤchlich zu einer verstƤrkten Migrationsbewegung fĆ¼hren. Die Analyse von Daten zu Eliten- und Hochqualifiziertenmigration in Ostasien, Europa und den USA fĆ¼hrt zu dem Ergebnis, dass diese dem Muster einer ā€žbrain circulationā€œ folgt und die StaatsbĆ¼rgerrechte dabei keine entscheidende Rolle spielen

    High temporal resolution parametric MRI monitoring of the initial ischemia/reperfusion phase in experimental acute kidney injury

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    Ischemia/reperfusion (I/R) injury, a consequence of kidney hypoperfusion or temporary interruption of blood flow is a common cause of acute kidney injury (AKI). There is an unmet need to better understand the mechanisms operative during the initial phase of ischemic AKI. Non-invasive parametric magnetic resonance imaging (MRI) may elucidate spatio-temporal pathophysiological changes in the kidney by monitoring the MR relaxation parameters T* and T, which are known to be sensitive to blood oxygenation. The aim of our study was to establish the technical feasibility of fast continuous T*/T mapping throughout renal I/R. MRI was combined with a remotely controlled I/R model and a segmentation model based semi-automated quantitative analysis. This technique enabled the detailed assessment of changes in all kidney regions during ischemia and early reperfusion. Significant changes in T* and T were observed shortly after induction of renal ischemia and during the initial reperfusion phase. Our study demonstrated for the first time that continuous and high temporal resolution parametric MRI is feasible for monitoring and characterization of I/R induced AKI in rats. This technique may help in the identification of the timeline of key events responsible for development of renal damage in hypoperfusion-induced AKI

    UniPROBE: an online database of protein binding microarray data on proteinā€“DNA interactions

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    The UniPROBE (Universal PBM Resource for Oligonucleotide Binding Evaluation) database hosts data generated by universal protein binding microarray (PBM) technology on the in vitro DNA-binding specificities of proteins. This initial release of the UniPROBE database provides a centralized resource for accessing comprehensive PBM data on the preferences of proteins for all possible sequence variants (ā€˜wordsā€™) of length k (ā€˜k-mersā€™), as well as position weight matrix (PWM) and graphical sequence logo representations of the k-mer data. In total, the database hosts DNA-binding data for over 175 nonredundant proteins from a diverse collection of organisms, including the prokaryote Vibrio harveyi, the eukaryotic malarial parasite Plasmodium falciparum, the parasitic Apicomplexan Cryptosporidium parvum, the yeast Saccharomyces cerevisiae, the worm Caenorhabditis elegans, mouse and human. Current web tools include a text-based search, a function for assessing motif similarity between user-entered data and database PWMs, and a function for locating putative binding sites along user-entered nucleotide sequences. The UniPROBE database is available at http://thebrain.bwh.harvard.edu/uniprobe/
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