| 1. |
- Cornelissen, Johannes H C, et al.
(författare)
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Global negative vegetation feedback to climate warming responses of leaf litter decomposition rates in cold biomes
- 2007
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Ingår i: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 10:7, s. 619-627
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Tidskriftsartikel (refereegranskat)abstract
- Whether climate change will turn cold biomes from large long-term carbon sinks into sources is hotly debated because of the great potential for ecosystem-mediated feedbacks to global climate. Critical are the direction, magnitude and generality of climate responses of plant litter decomposition. Here, we present the first quantitative analysis of the major climate-change-related drivers of litter decomposition rates in cold northern biomes worldwide.Leaf litters collected from the predominant species in 33 global change manipulation experiments in circum-arctic-alpine ecosystems were incubated simultaneously in two contrasting arctic life zones. We demonstrate that longer-term, large-scale changes to leaf litter decomposition will be driven primarily by both direct warming effects and concomitant shifts in plant growth form composition, with a much smaller role for changes in litter quality within species. Specifically, the ongoing warming-induced expansion of shrubs with recalcitrant leaf litter across cold biomes would constitute a negative feedback to global warming. Depending on the strength of other (previously reported) positive feedbacks of shrub expansion on soil carbon turnover, this may partly counteract direct warming enhancement of litter decomposition.
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| 2. |
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| 3. |
- Lee, Edward W, et al.
(författare)
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Neuropeptide Y (NPY) : A neurogenic mediator of angiogenesis
- 2004
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Ingår i: 7th International NPY Meeting Coimbra. ; , s. 36-36
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- NPY, previously known as a sympathetic vasoconstricting co-transmitter, recently has also emerged as an important vascular growth factor, stimulating proliferation of vascular smooth muscle and endothelial cells (ECs). Both in vitro and in vivo, NPY stimulates angiogenesis starting at sub-picomolar, non-vasoconstrictive concentrations, and with maximal effects similar to those of other known angiogenic factors e.g. vascular endothelial growth factor (VEGF). To determine if NPY is a physiological mediator in vivo, we studied 1 ) ischemic angiogenesis in a rodent model of femoral artery occlusion 2) vascular development in rats over-expressing NPY gene; 3) changes in angiogenesis with aging. Hindlimb ischemia increased local NPY release and shifted NPY receptor (R) expression from predominantly Yl to the Y2R type, and up-regulated dipeptidyl peptidase IV (DPPIV, peptidase forming Y2/YS agonist). Increasing local NPY levels 2-fold with a slow-release pellet (Il.g/14 days, below arterial occlusion), additionally induced YSR mRNA, and stimulated capillary angiogenesis and collateral vessel growth - leading to restoration of blood flow and contractile function of ischemic muscles. These effects were markedly reduced in Y2R-/- mice, as was NPY-induced aortic sprouting ex vivo; the latter was also reduced by anti-VEGF antibody and completely abolished in endothelial nitric oxide synthase (eNOS)-/- mice. The role of NPY in vascular development was further revealed by the severe impairment of spontaneous aortic sprouting in NPY-/- mice and changes in vascular density of non-ischemic muscles: reduction in Y2-/- mice and marked increase in NPY-Tg rats. With aging, in mice, NPY-induced angiogenesis decreased together with Y2 and DPPIV expression, and in human ECs, the proliferative effects of NPY declined too, similarly to those of VEGF or basic fibroblast growth factor (bFGF). Since NPY-induced EC proliferation was similarly blocked by anti-VEGF and anti-FGF antibodies in young and old patients, this suggests that age-induced impaired activity of the NPY-Y2R system could lead to lower secretion of these growth factors, in addition to decreased responsiveness of old vessels to VEGF and bFGF. Taken together, our studies indicate that NPY is a physiological neurogenic factor playing an important role ip revascularization of ischemic tissues and in age-related changes in vascular development. NPY's angiogenic activity requires Y2Rs and eNOS, and involves release of VEGF and bFGF. Thus, sympathetic nerve activity, via NPY, may be an important upstream mechanism triggering a cascade of molecular events leading to vascular remodeling during tissue ischemia and growth.
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| 4. |
- Lundberg, Sven-Erik, et al.
(författare)
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Chapter 7: Manufacture of Steel Tubular Products
- 2017
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Ingår i: The Making, Shaping and Treating of Steel. - Warrendale, PA : Association for Iron & Steel Technology (AIST). - 9781935117575 ; , s. 657-729
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 5. |
- Machard, Anaïs, et al.
(författare)
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Typical and extreme weather datasets for studying the resilience of buildings to climate change and heatwaves
- 2024
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Ingår i: Scientific Data. - : Springer. - 2052-4463. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- We present unprecedented datasets of current and future projected weather files for building simulations in 15 major cities distributed across 10 climate zones worldwide. The datasets include ambient air temperature, relative humidity, atmospheric pressure, direct and diffuse solar irradiance, and wind speed at hourly resolution, which are essential climate elements needed to undertake building simulations. The datasets contain typical and extreme weather years in the EnergyPlus weather file (EPW) format and multiyear projections in comma-separated value (CSV) format for three periods: historical (2001–2020), future mid-term (2041–2060), and future long-term (2081–2100). The datasets were generated from projections of one regional climate model, which were bias-corrected using multiyear observational data for each city. The methodology used makes the datasets among the first to incorporate complex changes in the future climate for the frequency, duration, and magnitude of extreme temperatures. These datasets, created within the IEA EBC Annex 80 “Resilient Cooling for Buildings”, are ready to be used for different types of building adaptation and resilience studies to climate change and heatwaves.
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