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- Brogaard, Sara, et al.
(författare)
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Rural reforms and changes in land management and attitudes: A case study from Inner Mongolia, China
- 2002
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Ingår i: Ambio: a Journal of Human Environment. - 0044-7447. ; 31:3, s. 219-225
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Tidskriftsartikel (refereegranskat)abstract
- The international science community stresses the importance of the local perspective in the context of dryland degradation. This paper explores changes in management and attitudes in a mixed farming system in northern China, since the introduction of the economic reforms in the early 1980s, and the following changes in land-use rights. The area encompasses a dune landscape scattered with crop-land, as well as the Daqinggou Nature Reserve, an area of natural vegetation. According to farmers new varieties of maize in combination with increased use of fertilizers have improved yields, though high yield variability persists due to erratic rainfall. Farmers acknowledge the importance of the 30-year contract on cultivated land in 1997 for their investment in long-term management, but emphasize the importance of chemical fertilizers for short-term economic survival. The farmers stressed the negative impact of grazing and cultivation on soil erosion and stated that differences in vegetation composition and cover in the nature reserve are due to anthropogenic factors.
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| 4. |
- Wihlborg, Anna-Karin, et al.
(författare)
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2,2 '-nitrophenylisatogen potentiates P2X(1) receptor mediated vascular contraction and blood pressure elevation
- 2003
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Ingår i: Drug Development Research (Proceedings of the Seventh International Symposium on Adenosine and Adenine Nucleotides - Part 2). - : Wiley. - 1098-2299 .- 0272-4391. ; 59:1, s. 82-87
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Konferensbidrag (refereegranskat)abstract
- The objective of this research was to examine the effects of chemical compounds with possible P2 receptor modulating effects and to characterize the potentiating effects of 2,2'-nitrophenylisatogen (NPI) on P2X(1) receptors in vitro and in vivo. Chemical compounds were tested in an in vitro pharmacological assay using vascular segments from the rat mesenteric artery stimulated by P2 receptor-specific agonists. Contractions were expressed as a percentage of 60 mM K+-induced contractions. Blood pressure was evaluated in pithed rats. NPI (30 muM) added 15 min before addition of the P2X(1) receptor-specific agonist alphabeta-MeATP increased the maximum vasoconstriction from 23% to 49% (an increase of 113%). Furthermore, NPI prevented the desensitization of repeated UP-MeATP contractions. Related compounds were examined, and 2-(3-methoxy-phenyl)-1-oxy-indol-3-one (MPI) had similar effects as NPI, but several others lacked effect. NPI had no effect on ADPbetaS (P2Y(1)) or acetylcholine-mediated vasodilatation, nor on UTP (P2Y(2/4)), UDP (P2Y(6)), or noradrenaline-mediated contractions. In pithed rats, the blood pressure response to 50 nmol/kg-infusion of alphabeta-MeATP was increased from 50+/-6 to 63+/-5 mmHg (P < 0.05), but had no effect on basal blood pressure or on the cardiovascular response to preganglionic nerve stimulation. In conclusion, NPI and MPI potentiates P2X(1) receptor vascular contractions in vitro and (NPI) blood pressure effects in vivo. It is possible that the effect is mediated by an inhibition of P2X(1) receptor desensitization. Drug Dev. Res. (C) Wiley-Liss, Inc.
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