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  • 1
    Publication Date: 2014-05-09
    Description: Rapid Arctic warming and sea-ice reduction in the Arctic Ocean are widely attributed to anthropogenic climate change. The Arctic warming exceeds the global average warming because of feedbacks that include sea-ice reduction and other dynamical and radiative feedbacks. We find that the most prominent annual mean surface and tropospheric warming in the Arctic since 1979 has occurred in northeastern Canada and Greenland. In this region, much of the year-to-year temperature variability is associated with the leading mode of large-scale circulation variability in the North Atlantic, namely, the North Atlantic Oscillation. Here we show that the recent warming in this region is strongly associated with a negative trend in the North Atlantic Oscillation, which is a response to anomalous Rossby wave-train activity originating in the tropical Pacific. Atmospheric model experiments forced by prescribed tropical sea surface temperatures simulate the observed circulation changes and associated tropospheric and surface warming over northeastern Canada and Greenland. Experiments from the Coupled Model Intercomparison Project Phase 5 (ref. 16) models with prescribed anthropogenic forcing show no similar circulation changes related to the North Atlantic Oscillation or associated tropospheric warming. This suggests that a substantial portion of recent warming in the northeastern Canada and Greenland sector of the Arctic arises from unforced natural variability.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ding, Qinghua -- Wallace, John M -- Battisti, David S -- Steig, Eric J -- Gallant, Ailie J E -- Kim, Hyung-Jin -- Geng, Lei -- England -- Nature. 2014 May 8;509(7499):209-12. doi: 10.1038/nature13260.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Earth and Space Sciences and Quaternary Research Center, University of Washington, Seattle, Washington 98195, USA. ; Department of Atmospheric Sciences, University of Washington, Seattle, Washington 98195, USA. ; School of Geography and Environmental Science, Monash University, Victoria 3800, Australia. ; Climate Research Department, APEC Climate Center, 12 Centum 7-ro, Haeundae-gu, Busan 612-020, South Korea.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24805345" target="_blank"〉PubMed〈/a〉
    Keywords: Air ; Arctic Regions ; Canada ; *Feedback ; Global Warming/*statistics & numerical data ; Greenland ; Hot Temperature ; Human Activities ; Ice Cover ; Models, Theoretical ; Pacific Ocean ; Seawater ; *Tropical Climate
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 2
    Publication Date: 2014-01-05
    Description: Pine Island Glacier has thinned and accelerated over recent decades, significantly contributing to global sea-level rise. Increased oceanic melting of its ice shelf is thought to have triggered those changes. Observations and numerical modeling reveal large fluctuations in the ocean heat available in the adjacent bay and enhanced sensitivity of ice-shelf melting to water temperatures at intermediate depth, as a seabed ridge blocks the deepest and warmest waters from reaching the thickest ice. Oceanic melting decreased by 50% between January 2010 and 2012, with ocean conditions in 2012 partly attributable to atmospheric forcing associated with a strong La Nina event. Both atmospheric variability and local ice shelf and seabed geometry play fundamental roles in determining the response of the Antarctic Ice Sheet to climate.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Dutrieux, Pierre -- De Rydt, Jan -- Jenkins, Adrian -- Holland, Paul R -- Ha, Ho Kyung -- Lee, Sang Hoon -- Steig, Eric J -- Ding, Qinghua -- Abrahamsen, E Povl -- Schroder, Michael -- New York, N.Y. -- Science. 2014 Jan 10;343(6167):174-8. doi: 10.1126/science.1244341. Epub 2014 Jan 2.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉British Antarctic Survey, Natural Environment Research Council (NERC), Cambridge, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24385606" target="_blank"〉PubMed〈/a〉
    Keywords: *Climate Change ; Freezing ; *Ice Cover ; *Islands
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 3
    Publication Date: 2018-07-28
    Description: Nanostructured carbon materials with large surface area and desired chemical functionalities have been attracting considerable attention because of their extraordinary physicochemical properties and great application potentials in catalysis, environment, and energy storage. However, the traditional approaches to fabricating these materials rely greatly on complex procedures and specific precursors. We present a simple, effective, and scalable strategy for the synthesis of functional carbon materials by transition metal–assisted carbonization of conventional small organic molecules. We demonstrate that transition metals can promote the thermal stability of molecular precursors and assist the formation of thermally stable polymeric intermediates during the carbonization process, which guarantees the successful preparation of carbons with high yield. The versatility of this synthetic strategy allows easy control of the surface chemical functionality, porosity, and morphology of carbons at the molecular level. Furthermore, the prepared carbons exhibit promising performance in heterogeneous catalysis and electrocatalysis.
    Electronic ISSN: 2375-2548
    Topics: Natural Sciences in General
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  • 4
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2018-04-06
    Description: Hematopoietic stem cell (HSC) maintenance depends on extrinsic cues. Currently, only local signals arising from the bone marrow niche have been shown to maintain HSCs. However, it is not known whether systemic factors also sustain HSCs. We assessed the physiological source of thrombopoietin (TPO), a key cytokine required for maintaining HSCs. Using Tpo DsRed-CreER knock-in mice, we showed that TPO is expressed by hepatocytes but not by bone marrow cells. Deletion of Tpo from hematopoietic cells, osteoblasts, or bone marrow mesenchymal stromal cells does not affect HSC number or function. However, when Tpo is deleted from hepatocytes, bone marrow HSCs are depleted. Thus, a cross-organ factor, circulating TPO made in the liver by hepatocytes, is required for bone marrow HSC maintenance. Our results demonstrate that systemic factors, in addition to the local niche, are a critical extrinsic component for HSC maintenance.
    Keywords: Cell Biology, Development
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 5
    Publication Date: 2018-06-02
    Description: Salinity causes osmotic stress to crops and limits their productivity. To understand the mechanism underlying soybean salt tolerance, proteomics approach was used to identify phosphoproteins altered by NaCl treatment. Results revealed that 412 of the 4698 quantitatively analyzed phosphopeptides were significantly up-regulated on salt treatment, including a phosphopeptide covering the serine 59 in the transcription factor GmMYB173. Our data showed that GmMYB173 is one of the three MYB proteins differentially phosphorylated on salt treatment, and a substrate of the casein kinase-II. MYB recognition sites exist in the promoter of flavonoid synthase gene GmCHS5 and one was found to mediate its recognition by GmMYB173, an event facilitated by phosphorylation. Because GmCHS5 catalyzes the synthesis of chalcone, flavonoids derived from chalcone were monitored using metabolomics approach. Results revealed that 24 flavonoids of 6745 metabolites were significantly up-regulated after salt treatment. We further compared the salt tolerance and flavonoid accumulation in soybean transgenic roots expressing the 35 S promoter driven cds and RNAi constructs of GmMYB173 and GmCHS5 , as well as phospho-mimic ( GmMYB173 S59D ) and phospho-ablative ( GmMYB173 S59A ) mutants of GmMYB173 . Overexpression of GmMYB173 S59D and GmCHS5 resulted in the highest increase in salt tolerance and accumulation of cyaniding-3-arabinoside chloride, a dihydroxy B-ring flavonoid. The dihydroxy B-ring flavonoids are more effective as anti-oxidative agents when compared with monohydroxy B-ring flavonoids, such as formononetin. Hence the salt-triggered phosphorylation of GmMYB173, subsequent increase in its affinity to GmCHS5 promoter and the elevated transcription of GmCHS5 likely contribute to soybean salt tolerance by enhancing the accumulation of dihydroxy B-ring flavonoids.
    Print ISSN: 1535-9476
    Electronic ISSN: 1535-9484
    Topics: Biology , Medicine
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  • 6
    Publication Date: 2018-09-20
    Description: The growing and pruning radial basis function (GAP-RBF) network is a promising sequential learning algorithm for prediction analysis, but the parameter selection of such a network is usually a non-convex problem and makes it difficult to handle. In this paper, a hybrid bioinspired intelligent algorithm is proposed to optimize GAP-RBF. Specifically, the excellent local convergence of particle swarm optimization (PSO) and the extensive search ability of genetic algorithm (GA) are both considered to optimize the weights and bias term of GAP-RBF. Meanwhile, a competitive mechanism is proposed to make the hybrid algorithm choose the appropriate individuals for effective search and further improve its optimization ability. Moreover, a decoupled extended Kalman filter (DEKF) method is introduced in this study to reduce the size of error covariance matrix and decrease the computational complexity for performing real-time predictions. In the experiments, three classic forecasting issues including abalone age, Boston house price and auto MPG are adopted for extensive test, and the experimental results show that our method performs better than PSO and GA these two single bioinspired optimization algorithms. What is more, our method via DEKF achieves the better results in comparison with the state-of-art sequential learning algorithms, such as GAP-RBF, minimal resource allocation network, resource allocation network using an extended Kalman filter and resource allocation network.
    Keywords: hybrid computing
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
    Published by Royal Society
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  • 7
    Publication Date: 2012-05-15
    Description: Pairing and recombination of homologous chromosomes are essential for ensuring reductional segregation in meiosis. However, the mechanisms by which chromosomes recognize their homologous partners are poorly understood. Here, we report that the sme2 gene encodes a meiosis-specific noncoding RNA that mediates homologous recognition in the fission yeast Schizosaccharomyces pombe. The sme2 locus shows robust pairing from early in meiotic prophase. The sme2 RNA transcripts accumulate at their respective gene loci and greatly enhance pairing of homologous loci: Deletion of the sme2 sequence eliminates this robust pairing, whereas transposition to other chromosomal sites confers robust pairing at those ectopic sites. Thus, we propose that RNA transcripts retained on the chromosome play an active role in recognition of homologous chromosomes for pairing.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ding, Da-Qiao -- Okamasa, Kasumi -- Yamane, Miho -- Tsutsumi, Chihiro -- Haraguchi, Tokuko -- Yamamoto, Masayuki -- Hiraoka, Yasushi -- New York, N.Y. -- Science. 2012 May 11;336(6082):732-6. doi: 10.1126/science.1219518.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe 651-2492, Japan.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22582262" target="_blank"〉PubMed〈/a〉
    Keywords: *Chromosome Pairing ; Chromosomes, Fungal/*physiology ; Genes, Fungal ; *Meiosis ; Models, Genetic ; Prophase ; RNA, Fungal/genetics ; RNA, Untranslated/*genetics ; RNA-Binding Proteins/genetics/metabolism ; Recombination, Genetic ; Schizosaccharomyces/*genetics/physiology ; Schizosaccharomyces pombe Proteins/genetics/metabolism ; Telomere/physiology ; Transcription, Genetic ; mRNA Cleavage and Polyadenylation Factors/genetics
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 8
    ISSN: 0020-1790
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0022-1910
    Keywords: Allatostatin ; Callatostatin ; Epoxidase ; Juvenile hormone ; Methyltransferase
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-0525
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract. The makespan, flow time and maximum lateness problems of scheduling a set of tasks with deadlines and increasing rates of processing times on a single machine are considered in this paper. We first show that, when the increasing rates of processing time are identical, the makespan problem is equivalent to the corresponding flow time problem. Both problems are solvable in $O(n^5)$ time by a dynamic programming algorithm. As an application of the dynamic programming algorithm, we demonstrate that the corresponding maximum lateness problem can be solved in $O(n^6\log n)$ time. We then show that the general makespan problem is strongly NP-complete. Thus, both the corresponding flow time problem and maximum lateness problem are also strongly NP-complete.
    Type of Medium: Electronic Resource
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