Search Results - (Author, Cooperation:A. D. Friend)
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1Latest Papers from Table of Contents or Articles in PressM. Raghavan ; M. Steinrucken ; K. Harris ; S. Schiffels ; S. Rasmussen ; M. DeGiorgio ; A. Albrechtsen ; C. Valdiosera ; M. C. Avila-Arcos ; A. S. Malaspinas ; A. Eriksson ; I. Moltke ; M. Metspalu ; J. R. Homburger ; J. Wall ; O. E. Cornejo ; J. V. Moreno-Mayar ; T. S. Korneliussen ; T. Pierre ; M. Rasmussen ; P. F. Campos ; B. Damgaard Pde ; M. E. Allentoft ; J. Lindo ; E. Metspalu ; R. Rodriguez-Varela ; J. Mansilla ; C. Henrickson ; A. Seguin-Orlando ; H. Malmstrom ; T. Stafford, Jr. ; S. S. Shringarpure ; A. Moreno-Estrada ; M. Karmin ; K. Tambets ; A. Bergstrom ; Y. Xue ; V. Warmuth ; A. D. Friend ; J. Singarayer ; P. Valdes ; F. Balloux ; I. Leboreiro ; J. L. Vera ; H. Rangel-Villalobos ; D. Pettener ; D. Luiselli ; L. G. Davis ; E. Heyer ; C. P. Zollikofer ; M. S. Ponce de Leon ; C. I. Smith ; V. Grimes ; K. A. Pike ; M. Deal ; B. T. Fuller ; B. Arriaza ; V. Standen ; M. F. Luz ; F. Ricaut ; N. Guidon ; L. Osipova ; M. I. Voevoda ; O. L. Posukh ; O. Balanovsky ; M. Lavryashina ; Y. Bogunov ; E. Khusnutdinova ; M. Gubina ; E. Balanovska ; S. Fedorova ; S. Litvinov ; B. Malyarchuk ; M. Derenko ; M. J. Mosher ; D. Archer ; J. Cybulski ; B. Petzelt ; J. Mitchell ; R. Worl ; P. J. Norman ; P. Parham ; B. M. Kemp ; T. Kivisild ; C. Tyler-Smith ; M. S. Sandhu ; M. Crawford ; R. Villems ; D. G. Smith ; M. R. Waters ; T. Goebel ; J. R. Johnson ; R. S. Malhi ; M. Jakobsson ; D. J. Meltzer ; A. Manica ; R. Durbin ; C. D. Bustamante ; Y. S. Song ; R. Nielsen ; E. Willerslev
American Association for the Advancement of Science (AAAS)
Published 2015Staff ViewPublication Date: 2015-07-23Publisher: American Association for the Advancement of Science (AAAS)Print ISSN: 0036-8075Electronic ISSN: 1095-9203Topics: BiologyChemistry and PharmacologyComputer ScienceMedicineNatural Sciences in GeneralPhysicsKeywords: Americas ; Gene Flow ; Genomics ; History, Ancient ; Human Migration/*history ; Humans ; Indians, North American/genetics/*history ; Models, Genetic ; SiberiaPublished by: -
2Articles: DFG German National LicensesStaff View
ISSN: 1365-3040Source: Blackwell Publishing Journal Backfiles 1879-2005Topics: BiologyNotes: Abstract. A model of photosynthesis (PGEN) is presented. The model assumes that optimal use is made of the leaf nitrogen available for partitioning between the carboxylase and thylakoid components. This results in predictions of Rubisco and chlorophyll concentrations very similar to those measured elsewhere. A function is incorporated which represents the detrimental effects of negative leaf water potentials on the Calvin cycle, producing a quantitative and mechanistic trade-off between CO2 entering, and H2O leaving, the leaf. Thus, an optimal stomatal conductance and associated internal partial pressure of CO2 exists for any given set of environmental conditions. The model calculates this optimal state for the leaf, which is its output. The model was subjected to changes in the following parameters: soil water potential, irradiance, ambient CO2 partial pressure, leaf temperature, leaf-to-air vapour pressure deficit, wind speed, atmospheric pressure, leaf nitrogen content, root dry weight and leaf width. These perturbations resulted in changes in predicted optimal conductance which were very similar to what has been observed. In general, as the capacity of the leaf to fix CO2 increased, so did the predicted optimal conductance, with the internal partial pressure of CO2 being maintained close to 22Pa.Type of Medium: Electronic ResourceURL: -
3Articles: DFG German National LicensesStaff View
ISSN: 1365-2486Source: Blackwell Publishing Journal Backfiles 1879-2005Topics: BiologyEnergy, Environment Protection, Nuclear Power EngineeringGeographyNotes: A dynamic, global vegetation model, hybrid v4.1 (Friend et al. 1997), was driven by transient climate output from the UK Hadley Centre GCM (HadCM2) with the IS92a scenario of increasing atmospheric CO2 equivalent, sulphate aerosols and predicted patterns of atmospheric N deposition. Changes in areas of vegetation types and carbon storage in biomass and soils were predicted for areas north of 50°N from 1860 to 2100. Hybrid is a combined biogeochemical, biophysical and biogeographical model of natural, potential ecosystems. The effect of periodic boreal forest fires was assessed by adding a simple stochastic fire model. Hybrid represents plant physiological and soil processes regulating the carbon, water and N cycles and competition between individuals of parameterized generalized plant types. The latter were combined to represent tundra, temperate grassland, temperate/mixed forest and coniferous forest. The model simulated the current areas and estimated carbon stocks in the four vegetation types.It was predicted that land areas above 50°N (about 23% of the vegetated global land area) are currently accumulating about 0.4 PgC y−1 (about 30% of the estimated global terrestrial sink) and that this sink could grow to 0.8–1.0 PgC y−1 by the second half of the next century and persist undiminished until 2100. This sink was due mainly to an increase in forest productivity and biomass in response to increasing atmospheric CO2, temperature and N deposition, and includes an estimate of the effect of boreal forest fire, which was estimated to diminish the sink approximately by the amount of carbon emitted to the atmosphere during fires. Averaged over the region, N deposition contributed about 18% to the sink by the 2080 s. As expected, climate change (temperature, precipitation, solar radiation and saturation pressure deficit) and N deposition without increasing atmospheric CO2 produced a carbon source. Forest areas expanded both south and north, halving the current tundra area by 2100. This expansion contributed about 30% to the sink by the 2090 s. Tundra areas which were not invaded by forest fluctuated from sink to source. It was concluded that a high latitude carbon sink exists at present and, even assuming little effect of N deposition, no forest expansion and continued boreal forest fires, the sink is likely to persist at its current level for a century.Type of Medium: Electronic ResourceURL: -
4Articles: DFG German National LicensesReichstein, M. ; Viovy, N. ; Granier, A. ; Ogée, J. ; Allard, V. ; Aubinet, M. ; Buchmann, N. ; Bernhofer, Chr. ; Carrara, A. ; Chevallier, F. ; De Noblet, N. ; Friend, A. D. ; Friedlingstein, P. ; Grünwald, T. ; Heinesch, B. ; Keronen, P. ; Knohl, A. ; Krinner, G. ; Loustau, D. ; Manca, G. ; Matteucci, G. ; Miglietta, F. ; Ourcival, J. M. ; Papale, D. ; Pilegaard, K.
[s.l.] : Nature Publishing Group
Published 2005Staff ViewISSN: 1476-4687Source: Nature Archives 1869 - 2009Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsNotes: [Auszug] Future climate warming is expected to enhance plant growth in temperate ecosystems and to increase carbon sequestration. But although severe regional heatwaves may become more frequent in a changing climate, their impact on terrestrial carbon cycling is unclear. Here we report measurements of ...Type of Medium: Electronic ResourceURL: