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  • 1
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    Nature Publishing Group (NPG)
    Publikationsdatum: 2009-12-25
    Beschreibung: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Caro, Tim -- Sherman, Paul -- England -- Nature. 2009 Dec 24;462(7276):985. doi: 10.1038/462985b.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20033023" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Animals, Wild ; *Conservation of Natural Resources/methods ; *Ecosystem
    Print ISSN: 0028-0836
    Digitale ISSN: 1476-4687
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Publikationsdatum: 2009-12-25
    Beschreibung: Riverine organic matter supports of the order of one-fifth of estuarine metabolism. Coastal ecosystems are therefore sensitive to alteration of both the quantity and lability of terrigenous dissolved organic matter (DOM) delivered by rivers. The lability of DOM is thought to vary with age, with younger, relatively unaltered organic matter being more easily metabolized by aquatic heterotrophs than older, heavily modified material. This view is developed exclusively from work in watersheds where terrestrial plant and soil sources dominate streamwater DOM. Here we characterize streamwater DOM from 11 coastal watersheds on the Gulf of Alaska that vary widely in glacier coverage (0-64 per cent). In contrast to non-glacial rivers, we find that the bioavailability of DOM to marine microorganisms is significantly correlated with increasing (14)C age. Moreover, the most heavily glaciated watersheds are the source of the oldest ( approximately 4 kyr (14)C age) and most labile (66 per cent bioavailable) DOM. These glacial watersheds have extreme runoff rates, in part because they are subject to some of the highest rates of glacier volume loss on Earth. We estimate the cumulative flux of dissolved organic carbon derived from glaciers contributing runoff to the Gulf of Alaska at 0.13 +/- 0.01 Tg yr(-1) (1 Tg = 10(12) g), of which approximately 0.10 Tg is highly labile. This indicates that glacial runoff is a quantitatively important source of labile reduced carbon to marine ecosystems. Moreover, because glaciers and ice sheets represent the second largest reservoir of water in the global hydrologic system, our findings indicate that climatically driven changes in glacier volume could alter the age, quantity and reactivity of DOM entering coastal oceans.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hood, Eran -- Fellman, Jason -- Spencer, Robert G M -- Hernes, Peter J -- Edwards, Rick -- D'Amore, David -- Scott, Durelle -- England -- Nature. 2009 Dec 24;462(7276):1044-7. doi: 10.1038/nature08580.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Environmental Science and Geography Program, University of Alaska Southeast, Juneau, Alaska 99801, USA. eran.hood@uas.alaska.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20033045" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Alaska ; Carbon/analysis ; *Ecosystem ; Fresh Water/*chemistry ; Humic Substances/*analysis ; *Ice Cover/chemistry ; Marine Biology ; Pacific Ocean ; Spectrometry, Fluorescence ; Water Movements
    Print ISSN: 0028-0836
    Digitale ISSN: 1476-4687
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Publikationsdatum: 2009-12-25
    Beschreibung: The ranges of plants and animals are moving in response to recent changes in climate. As temperatures rise, ecosystems with 'nowhere to go', such as mountains, are considered to be more threatened. However, species survival may depend as much on keeping pace with moving climates as the climate's ultimate persistence. Here we present a new index of the velocity of temperature change (km yr(-1)), derived from spatial gradients ( degrees C km(-1)) and multimodel ensemble forecasts of rates of temperature increase ( degrees C yr(-1)) in the twenty-first century. This index represents the instantaneous local velocity along Earth's surface needed to maintain constant temperatures, and has a global mean of 0.42 km yr(-1) (A1B emission scenario). Owing to topographic effects, the velocity of temperature change is lowest in mountainous biomes such as tropical and subtropical coniferous forests (0.08 km yr(-1)), temperate coniferous forest, and montane grasslands. Velocities are highest in flooded grasslands (1.26 km yr(-1)), mangroves and deserts. High velocities suggest that the climates of only 8% of global protected areas have residence times exceeding 100 years. Small protected areas exacerbate the problem in Mediterranean-type and temperate coniferous forest biomes. Large protected areas may mitigate the problem in desert biomes. These results indicate management strategies for minimizing biodiversity loss from climate change. Montane landscapes may effectively shelter many species into the next century. Elsewhere, reduced emissions, a much expanded network of protected areas, or efforts to increase species movement may be necessary.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Loarie, Scott R -- Duffy, Philip B -- Hamilton, Healy -- Asner, Gregory P -- Field, Christopher B -- Ackerly, David D -- England -- Nature. 2009 Dec 24;462(7276):1052-5. doi: 10.1038/nature08649.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Carnegie Institution for Science, Department of Global Ecology, Stanford, California 94305, USA. loarie@stanford.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20033047" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Biodiversity ; Conservation of Natural Resources ; Ecosystem ; *Global Warming ; *Models, Biological ; Time Factors
    Print ISSN: 0028-0836
    Digitale ISSN: 1476-4687
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Publikationsdatum: 2009-12-23
    Beschreibung: Reprogramming of somatic cell nuclei to yield induced pluripotent stem (iPS) cells makes possible derivation of patient-specific stem cells for regenerative medicine. However, iPS cell generation is asynchronous and slow (2-3 weeks), the frequency is low (〈0.1%), and DNA demethylation constitutes a bottleneck. To determine regulatory mechanisms involved in reprogramming, we generated interspecies heterokaryons (fused mouse embryonic stem (ES) cells and human fibroblasts) that induce reprogramming synchronously, frequently and fast. Here we show that reprogramming towards pluripotency in single heterokaryons is initiated without cell division or DNA replication, rapidly (1 day) and efficiently (70%). Short interfering RNA (siRNA)-mediated knockdown showed that activation-induced cytidine deaminase (AID, also known as AICDA) is required for promoter demethylation and induction of OCT4 (also known as POU5F1) and NANOG gene expression. AID protein bound silent methylated OCT4 and NANOG promoters in fibroblasts, but not active demethylated promoters in ES cells. These data provide new evidence that mammalian AID is required for active DNA demethylation and initiation of nuclear reprogramming towards pluripotency in human somatic cells.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2906123/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2906123/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bhutani, Nidhi -- Brady, Jennifer J -- Damian, Mara -- Sacco, Alessandra -- Corbel, Stephane Y -- Blau, Helen M -- AG009521/AG/NIA NIH HHS/ -- AG024987/AG/NIA NIH HHS/ -- AI007328/AI/NIAID NIH HHS/ -- R01 AG009521/AG/NIA NIH HHS/ -- R01 AG009521-25/AG/NIA NIH HHS/ -- R01 AG024987/AG/NIA NIH HHS/ -- R01 AG024987-05/AG/NIA NIH HHS/ -- T32 AI007328/AI/NIAID NIH HHS/ -- U01 HL100397/HL/NHLBI NIH HHS/ -- England -- Nature. 2010 Feb 25;463(7284):1042-7. doi: 10.1038/nature08752.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Baxter Laboratory for Stem Cell Biology, Institute for Stem Cell Biology and Regenerative Medicine, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305-5175, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20027182" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Cell Division ; Cell Fusion ; Cell Line ; Cells, Cultured ; Cellular Reprogramming/genetics/*physiology ; Chromatin Immunoprecipitation ; Cytidine Deaminase/deficiency/genetics/*metabolism ; DNA/chemistry/genetics/metabolism ; *DNA Methylation ; DNA Replication ; Embryonic Stem Cells/cytology/metabolism ; Fibroblasts/cytology/metabolism ; Gene Expression Regulation ; Gene Knockdown Techniques ; Homeodomain Proteins/genetics ; Humans ; Induced Pluripotent Stem Cells/*cytology/enzymology/*metabolism ; Lung/cytology/embryology ; Mice ; Models, Biological ; Octamer Transcription Factor-3/genetics ; Promoter Regions, Genetic/genetics ; Time Factors
    Print ISSN: 0028-0836
    Digitale ISSN: 1476-4687
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
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    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 2009-12-19
    Beschreibung: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Stokstad, Erik -- New York, N.Y. -- Science. 2009 Dec 18;326(5960):1618. doi: 10.1126/science.326.5960.1618.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20019268" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; *Conservation of Natural Resources ; *Ecosystem ; Oceans and Seas ; *Public Policy ; *Seawater ; United States ; United States Government Agencies/organization & administration
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Publikationsdatum: 2009-12-18
    Beschreibung: Avian brood parasites and their hosts provide model systems for investigating links between recognition, learning, and their fitness consequences. One major evolutionary puzzle has continued to capture the attention of naturalists for centuries: why do hosts of brood parasites generally fail to recognize parasitic offspring after they have hatched from the egg, even when the host and parasitic chicks differ to almost comic degrees? One prominent theory to explain this pattern proposes that the costs of mistakenly learning to recognize the wrong offspring make recognition maladaptive. Here we show that American coots, Fulica americana, can recognize and reject parasitic chicks in their brood by using learned cues, despite the fact that the hosts and the brood parasites are of the same species. A series of chick cross-fostering experiments confirm that coots use first-hatched chicks in a brood as referents to learn to recognize their own chicks and then discriminate against later-hatched parasitic chicks in the same brood. When experimentally provided with the wrong reference chicks, coots can be induced to discriminate against their own offspring, confirming that the learning errors proposed by theory can exist. However, learning based on hatching order is reliable in naturally parasitized coot nests because host eggs hatch predictably ahead of parasite eggs. Conversely, a lack of reliable information may help to explain why the evolution of chick recognition is not more common in hosts of most interspecific brood parasites.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shizuka, Daizaburo -- Lyon, Bruce E -- England -- Nature. 2010 Jan 14;463(7278):223-6. doi: 10.1038/nature08655. Epub 2009 Dec 16.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, California 95064, USA. shizuka@biology.ucsc.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20016486" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; *Biological Evolution ; Birds/*parasitology/*physiology ; British Columbia ; Cues ; Discrimination Learning/*physiology ; Feeding Behavior/physiology ; Genetic Fitness ; Nesting Behavior/*physiology ; Ovum/growth & development ; Pattern Recognition, Visual/physiology ; Survival Rate ; Time Factors ; Wetlands
    Print ISSN: 0028-0836
    Digitale ISSN: 1476-4687
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
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    Nature Publishing Group (NPG)
    Publikationsdatum: 2009-12-18
    Beschreibung: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Tollefson, Jeff -- England -- Nature. 2009 Dec 17;462(7275):834-5. doi: 10.1038/462834a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20016566" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): *Biomass ; Congresses as Topic ; Conservation of Natural Resources/methods/trends ; Denmark ; *Ecosystem ; Forestry/methods/trends ; Global Warming/prevention & control ; *Internationality ; *Spacecraft ; Trees/*growth & development ; Tropical Climate
    Print ISSN: 0028-0836
    Digitale ISSN: 1476-4687
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
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    Nature Publishing Group (NPG)
    Publikationsdatum: 2009-12-18
    Beschreibung: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Dixon, Nicholas E -- England -- Nature. 2009 Dec 17;462(7275):854-5. doi: 10.1038/462854a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20016583" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Bacteriophage T7/enzymology/genetics/*physiology ; DNA Primase/chemistry/*metabolism ; DNA Replication/*physiology ; DNA, Viral/biosynthesis/metabolism ; DNA-Directed DNA Polymerase/chemistry/*metabolism ; *Models, Biological ; Multienzyme Complexes/chemistry/*metabolism ; RNA/biosynthesis ; Time Factors
    Print ISSN: 0028-0836
    Digitale ISSN: 1476-4687
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Publikationsdatum: 2009-12-18
    Beschreibung: With polar temperatures approximately 3-5 degrees C warmer than today, the last interglacial stage (approximately 125 kyr ago) serves as a partial analogue for 1-2 degrees C global warming scenarios. Geological records from several sites indicate that local sea levels during the last interglacial were higher than today, but because local sea levels differ from global sea level, accurately reconstructing past global sea level requires an integrated analysis of globally distributed data sets. Here we present an extensive compilation of local sea level indicators and a statistical approach for estimating global sea level, local sea levels, ice sheet volumes and their associated uncertainties. We find a 95% probability that global sea level peaked at least 6.6 m higher than today during the last interglacial; it is likely (67% probability) to have exceeded 8.0 m but is unlikely (33% probability) to have exceeded 9.4 m. When global sea level was close to its current level (〉or=-10 m), the millennial average rate of global sea level rise is very likely to have exceeded 5.6 m kyr(-1) but is unlikely to have exceeded 9.2 m kyr(-1). Our analysis extends previous last interglacial sea level studies by integrating literature observations within a probabilistic framework that accounts for the physics of sea level change. The results highlight the long-term vulnerability of ice sheets to even relatively low levels of sustained global warming.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kopp, Robert E -- Simons, Frederik J -- Mitrovica, Jerry X -- Maloof, Adam C -- Oppenheimer, Michael -- England -- Nature. 2009 Dec 17;462(7275):863-7. doi: 10.1038/nature08686.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Geosciences, Princeton University, Princeton, New Jersey 08544, USA. rkopp@alumni.caltech.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20016591" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Algorithms ; Antarctic Regions ; Global Warming/*statistics & numerical data ; Greenhouse Effect ; Greenland ; History, 21st Century ; History, Ancient ; *Ice Cover ; Models, Theoretical ; Oceans and Seas ; *Probability ; Seawater/*analysis ; *Temperature ; Time Factors ; Uncertainty
    Print ISSN: 0028-0836
    Digitale ISSN: 1476-4687
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
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    Nature Publishing Group (NPG)
    Publikationsdatum: 2009-12-18
    Beschreibung: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Clark, Peter U -- Huybers, Peter -- England -- Nature. 2009 Dec 17;462(7275):856-7. doi: 10.1038/462856a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20016585" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Antarctic Regions ; Global Warming/*statistics & numerical data ; Greenhouse Effect ; Greenland ; History, 21st Century ; History, Ancient ; *Ice Cover ; Oceans and Seas ; Seawater/*analysis ; Temperature ; Time Factors
    Print ISSN: 0028-0836
    Digitale ISSN: 1476-4687
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
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