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PHILIP D. RABINOWITZ MEHDI Z. YUSIFOV JESSICA ARNOLDI EYAL HAKIM 《Ocean Development & International Law》2013,44(1):19-40
The Caspian Sea region contains oil and gas reserves that are comparable to those of other of the world's fossil-fuel-producing regions, excluding the Middle East. We review here the economic, environmental, and complicated geopolitical concerns with respect to exploration and recovery of the region's fossil fuels. These include mud volcanoes, gas hydrates, earthquakes, pollution, rapid changes in sea level, desertification, ownership of resources, and the transportation routes of fossil fuels. Significant advances have been made concerning these problems in the short time since the breakup of the Soviet Union, fueling optimism for the future of the region.- 相似文献
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Wen-Bin JIANG Ma HAKIM Lei LUO Bo-Wen LI Shi-Long YANG Yu-Zhu SONG Ren LAI Qiu-Min LU 《动物学研究》2015,36(3):174-177
As a group of intestinal hormones and neurotransmitters, cholecystokinins(CCKs) regulate and affect pancreatic enzyme secretion, gastrointestinal motility, pain hypersensitivity, digestion and satiety, and generally contain a DYMGWMDFG sequence at the C-terminus. Many CCKs have been reported in mammals. However, only a few have been reported in amphibians, such as Hyla nigrovittata, Xenopus laevis, and Rana catesbeiana, with none reported in urodele amphibians like newts and salamanders. Here, a CCK called CCK-TV was identified and characterized from the skin of the salamander Tylototriton verrucosus. This CCK contained an amino acid sequence of DYMGWMDF-NH2 as seen in other CCKs. A c DNA encoding the CCK precursor containing 129 amino acid residues was cloned from the c DNA library of T. verrucosus skin. The CCK-TV had the potential to induce the contraction of smooth muscle strips isolated from porcine gallbladder, eliciting contraction at a concentration of 5.0x10-11 mol/L and inducing maximal contraction at a concentration of 2.0x10-6 mol/L. The EC50 was 13.6 nmol/L. To the best of our knowledge, this is the first report to identify the presence of a CCK in an urodele amphibian. 相似文献
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Respiration acclimation contributes to high carbon-use efficiency in a seasonally dry pine forest 总被引:1,自引:0,他引:1
KADMIEL MASEYK JOSÉ M. GRÜNZWEIG† EYAL ROTENBERG DAN YAKIR 《Global Change Biology》2008,14(7):1553-1567
Predictions of warming and drying in the Mediterranean and other regions require quantifying of such effects on ecosystem carbon dynamics and respiration. Long‐term effects can only be obtained from forests in which seasonal drought is a regular feature. We carried out measurements in a semiarid Pinus halepensis (Aleppo pine) forest of aboveground respiration rates of foliage, Rf, and stem, Rt over 3 years. Component respiration combined with ongoing biometric, net CO2 flux [net ecosystem productivity (NEP)] and soil respiration measurements were scaled to the ecosystem level to estimate gross and net primary productivity (GPP, NPP) and carbon‐use efficiency (CUE=NPP/GPP) using 6 years data. GPP, NPP and NEP were, on average, 880, 350 and 211 g C m?2 yr?1, respectively. The above ground respiration made up half of total ecosystem respiration but CUE remained high at 0.4. Large seasonal variations in both Rf and Rt were not consistently correlated with seasonal temperature trends. Seasonal adjustments of respiration were observed in both the normalized rate (R20) and short‐term temperature sensitivity (Q10), resulting in low respiration rates during the hot, dry period. Rf in fully developed needles was highest over winter–spring, and foliage R20 was correlated with photosynthesis over the year. Needle growth occurred over summer, with respiration rates in developing needles higher than the fully developed foliage at most times. Rt showed a distinct seasonal maximum in May irrespective of year, which was not correlated to the winter stem growth, but could be associated with phenological drivers such as carbohydrate re‐mobilization and cambial activity. We show that in a semiarid pine forest photosynthesis and stem growth peak in (wet) winter and leaf growth in (dry) summer, and associated adjustments of component respiration, dominated by those in R20, minimize annual respiratory losses. This is likely a key for maintaining high CUE and ecosystem productivity similar to much wetter sites, and could lead to different predictions of the effect of warming and drying climate on productivity of pine forests than based on short‐term droughts. 相似文献