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Balancing sustained economic growth with energy security and environmental and climate change constraints is a common but difficult challenge. China, as the largest energy consumer in the world – 90% of which is fossil fuel-based – faces the enormous task of transforming its energy mix to low-emissions. CO₂ has been successfully injected for the purposes of both carbon capture and storage (CCS) and enhanced oil recovery (EOR). This study employs life cycle assessment to quantify the CO₂ emissions from the CCS-EOR system to analyze net CO₂ emissions. This system includes carbon capture, transportation, EOR, downstream, and consumption. Our model analyzes life cycle CO₂ emissions from plants of integrated gasification combined cycle (IGCC) with CCS, pulverized coal plants (PC) with CCS, and oxy-fuel plants with CCS while we use technologies of fractionation, refrigeration, Ryan-Holmes, and membrance in the process of EOR. Total CO₂ emissions are 114.69-121.50 Mt CO₂e, 222.95-236.19 Mt CO₂e, and 49.09-51.96 Mt CO₂e from IGCC, PC, and oxy-fuel plants, respectively, based on IGCC with 426 MW, PC with 600 MW, and oxy-fuel with 200 MW in China. Emissions from the combustion of refined petroleum fuel is the most of total emissions – from 66.21% to 71.35%, emissions from EOR are 14.27-19.32%, emissions from downstream are 8.47-9.13%, emissions from capture are 4.12-5.09%, and emissions from transportation are 0.47-1.61%. Based on these results, CCS-EOR (where CO₂ is sourced from IGCC, PC and oxy-fuel plants) provides one potential means for producing electricity and oil to meet growing energy demand and reducing CO₂ emissions to abate global warming.
The loss of biological and economic productivity in the dryland regions hinders the prospects of reducing poverty. The method of vulnerability assessment has been broadly employed to evaluate the potential impact of environmental change and pinpoint the future adaptations on regional or global levels, which could help in the identification and development of coping strategies for dryland regions. The present study provides a vulnerability assessment for the semiarid grasslands of the Xilingol, Mongolia Plateau – a typical dryland area that has been suffering from land degradation for a long period. An exposure-sensitivity index was calculated using Spatial Principal Component Analysis for 19 climate and anthropogenic indicators that had a strong correlation with observed grassland degradation. This indicator was compared with an adaptive capacity index, constructed using principal component analysis for 27 relevant variables from the aspects of location advantage, economic level, resources, and social efficiency. The results show that the northeastern part of Xilingol is least vulnerable due to more favorable and available natural resources, including high precipitation, productive grassland, etc., and greater economic development. By contrast, the areas in the southwest, with harsh environmental conditions and a poor socio-economic infrastructure, have the greatest vulnerability. These regions are in dire need for targeted adaptation measures to further decline in human well-being. Through analyzing the results of SPCA and PCA analysis, the entry points for vulnerability reduction were distinguished and the pertinent suggestions were clearly brought forward from the aspects of reducing exposure- sensitivity and improving adaptive capacity.
Study of the radial growth response to climate factors at different tree ages is essential for predicting forest dynamics and formulating correct management policies. In this study, we analysed the growth responsiveness of Picea crassifolia to climate conditions, and evaluated its relationship to tree age at the individual tree scale, in the transitional zone between regions affected by the East Asian monsoon and winds blowing from the west (westerlies) in the Qilian Mountains. On three study sites, 150 cores were taken from 75 trees. Pearson correlation coefficients were calculated between the standardized tree-ring series of each core (and chronology) and climatic factors which were utilized to research the climate-growth relationships. Quadratic polynomial fitting was used to test the relationships between tree age, chronological parameters, and the radial growth response to climate. Radial growth was positively influenced by total precipitation for the previous July-September and the current May-July. Additionally, radial growth was negatively correlated with the total monthly precipitation for the current September, and the mean monthly temperature for the previous July. Trees younger than 80 years old showed a stronger response to accumulative precipitation in the previous July-September, those older than 160 years old showed a stronger response to precipitation at the end of current growing season, while those of 140–160 years old showed a weaker response to precipitation in the current May-July.
Alpine treeline is an important ecological boundary, marked by a change in site conditions and plant communities when crossing the forest limit, and tree growth at treeline is strongly constrained by the harsh environment. Finer resolution studies of tree radial variation on short temporal scales can be useful to explore the main physical variables that trigger the radial growth. From 19th Oct. 2008 to 25th Oct. 2009, we continuously monitored the stem radial variation of Picea meyeri Rebd. Et Wils trees using point dendrometers, at the treeline of Luya Mountains (altitude 2700 m a.s.l.), North China. Our results showed that there were two reverse daily variation patterns in the warm and cold seasons, which were related to the daily transpiration course and daily stem freeze-thaw cycles, respectively. Annual stem radial growth of Picea meyeri was divided into the four distinct periods: 1) spring stem rehydration, 2) summer stem rapid growth, 3) autumn stem dehydration contraction and 4) winter stem stagnation. The stem radial variation of Picea meyeri at the alpine treeline was closely dependent on climate conditions. Soil temperature was the most important factor affecting radial growth, which determined the initiation of radial growth and the cambial activity during the growing season.
In our previous study, 25 Hsf gene homologues were identified and analyzed in maize. However, the exact functions of these gene family members are unclear at present. Here, we report the isolation and characterization of a strongly heat-induced HsfA2 gene from maize, ZmHsf04, and show its function in the heat/salt-stress response. Subcellular location assays showed that the ZmHsf04 protein is localized to the nucleus. Transcription activation data demonstrate that an AHA2 domain protein is necessary for the transcriptional activity of ZmHsf04. Furthermore, the function of ZmHsf04 was characterized in detail in transgenic plants of Arabidopsis thaliana Col-0. Overexpression of ZmHsf04 in Arabidopsis enhanced thermotolerance and positively regulated short-term-acquired thermotolerance. In addition, ZmHsf04 significantly improved salt tolerance and increased the sensitivity to abscisic acid in transgenic Arabidopsis. Overexpression of ZmHsf04 in Col-0 plants significantly up-regulated the expression of heat-specific HSP genes (AtHsp25.3-P, AtHsp18.2-CI, and AtHsp70B) and stress-related genes (AtAPX2 and AtGolS1) compared to the wild type. In summary, we have characterized a transcriptional regulator, ZmHsf04, which has important functions in enhancing heat and salt tolerance in plants.
Surface water samples were collected from 24 sampling sites throughout the Le’an River during wet and dry seasons. The concentrations of dissolved heavy metals were determined by inductively coupled plasma-mass spectrometry (ICP-MS). The sources of dissolved heavy metals in the Le’an River were investigated based on the seasonal and spatial variations. The results demonstrated that significant seasonality of dissolved heavy metals concentrations were found in the Le’an River, and high concentrations in dry season due to the precipitation dilution effect. Spatially, higher concentrations of selected dissolved heavy metals were distributed in the mining area, which was significantly influenced by mining activities. It was found that sites within the mining area suffered from serious pollution based on the calculated HPI and MPI. According to human health risk assessment, it was indicated that As, Co, and Cd were the major contributors to exposure to local inhabitants. The exposure risks of the adults were less sensitive compared to the children, and oral ingestion was the primary exposure pathway. Multivariate statistical analyses revealed that different groups of heavy metals were characteristics of the disparate source associated with mineral exploration, urban and agricultural activities, and geogenic origins. Hierarchical agglomerative CA grouped all the sampling sites into three clusters based on the data set of exposure risk to human health and aquatic life. In cluster 2, concentrations of Cd and As were higher than drinking water quality of WHO and Chinese standards.
Linking the response of tree growth to global warming is a key to fully appreciating the impact of climate change on forests. To examine the impacts of temperature and precipitation on tree growth, we studied the radial growth of Pinus tabulaeformis along an altitude gradient from 2032 m a.s.l. to 2361 m a.s.l. on the Helan Mountains, which is almost the northwestern limit of P. tabulaeformis distribution in China. The results showed that, radial growth of P. tabulaeformis decreased significantly (P <0.05) at the low altitude (2032 m a.s.l.) and remained almost steady at the middle and high altitude (2200 m a.s.l. and 2361 m a.s.l.) during the past decades, which was attributed to different climate-radial growth relationships at different altitudes. Total precipitation from the previous July to the current June was an important and effective climatic factor for radial growth at all altitudes. Radial growth was negatively correlated with the mean temperature of the current March at the low altitude and was positively and negatively correlated with the mean temperature of the previous October and the current July at the high altitude, respectively. Increasing temperature of the March under the context of global warming was the main reason for growth reduction at the low altitude. Radial growth at the middle and high altitudes didn't suffer from global warming. It was inferred that conifers at low altitudes of the species' dry distribution limit were more vulnerable to global warming. To cope with possible intensified drought in the growing season and growth reduction in the future, thinning and afforestation should be carried out in the forests, especially at low altitudes.
Fruit ripening is generally attributed to disassembly of cellular wall, particularly due to solubilisation and depolymerisation of pectin and hemicellulose. Experiments were conducted to test effects of hydroxyl radicals (OH) on the scission of cellular wall polysaccharides from pulp tissues of banana fruit at different ripening stage. Cellular wall materials were isolated from pulp tissues of banana fruit at different ripening stages. Two pectic fractions, water soluble pectin (WSP) and acid soluble pectin (ASP), and two hemicellulosic fractions, 1 M KOH soluble hemicellulose (HC1) and 4 M KOH soluble hemicellulos (HC2), were obtained from the cellular wall materials from pulp tissues, respectively. Effects of OH induced by the Fenton reaction on the scission of pectin and hemicellulose in vitro were investigated. As fruit ripening progressed, the sugar components of the WSP, HC1 and HC2 attacked by OH showed obvious molecular-mass downshifts. Thus, OH caused the disassembly of polysaccharides (WSP, ASP, HC1 and HC2) from cellular walls of pulp tissues of banana fruit, demonstrated by the reduced molecular mass distribution. Moreover, OH production in pulp tissues increased significantly as banana fruit ripened, which further help account for the role of OH in accelerated fruit ripening.
Compared with standard vessels, a slender catamaran with a semi-submerged bow (SSB) demonstrates superior seakeeping performance. To predict the motion of an SSB catamaran, computational fluid dynamics methods are adopted in this study and results are validated through small-scale model tests. The pitch, heave, and vertical acceleration are calculated at various wavelengths and speeds. Based on the overset grid and motion region methods, this study obtains the motion responses of an SSB catamaran in regular head waves. The results of the numerical studies are validated with the experimental data and show that the overset grid method is more accurate in predicting the motion of an SSB catamaran; the errors can be controlled within 20%. The movement data in regular waves shows that at a constant speed, the motion response initially increases and then decreases with increasing wavelength. This motion response peak is due to the encountering frequency being close to the natural frequency. Under identical sea conditions, the motion response increases with the increasing Froude number. The motion prediction results, that derive from a shortterm irregular sea state, show that there is an optimal speed range that can effectively reduce the amplitude of motion
Acyl-ACP thioesterases are responsible for the export of fatty acids produced by the de novo fatty acid synthesis system from the plastid. A fatty acyl–acyl carrier protein thioesterase (CpFATB) was isolated from a Chimonanthus praecox (linn.) Link. (wintersweet) cDNA library. This gene was subsequently transferred into Populus deltoides CL 9 P. euramericana CL ‘‘NL895’’ through Agrobacterium tumefaciens-mediated leaf disc transformation. The transgenic plants were confirmed by polymerase chain reaction (PCR) analysis and Southern hybridization. Three positive transgenic lines each with a single T-DNA insertion were obtained. Reverse transcription PCR (RT-PCR) confirmed CpFATB expression in transformed plants after short-term exposure to drought. When exposed to drought stress, transgenic plants showed higher superoxide dismutase (SOD) activity, peroxidase (POD) activity, catalase (CAT) activity, chlorophyll a content, chlorophyll b content and total chlorophyll content compared with untransformed plants. Malondialdehyde (MDA) content, electric conductivity and net photosynthetic rate of the transgenic plants were lower than untransgenic plants. The results of physiological indices showed that the overexpression of CpFATB in plants exhibited higher drought stress tolerance under drought stress condition compared to the untransformed control plants. Our data further confirmed and highlighted the functions of CpFATB in enhancing plants drought tolerance and may provide a plausible approach to breed plants combating drought stress and enlarging living scope.
Flowering at a suitable time is critical for ensuring reproductive success in the plant life cycle. The transition from vegetative growth to reproduction development is finely tuned by environmental and endogenous signals. To date, control of flowering involves five genetically defined pathways. However, the role of type-A response regulator genes in regulation of this process remains largely unclear. In the present study, we cloned and characterized a type-A response regulator gene (RhRR1) in rose. The expression of RhRR1 significantly increased in axillary bud during the transition from the vegetative growth to the start of floral differentiation, and in rose flowers in response to exogenous cytokinin or 1-methylcyclopropene (1-MCP) treatments, while that expression was markedly repressed by ethylene treatment. RhRR1 has the highest degree of sequence homology to AtARR8 and AtARR9, and is localized in the nucleus. Ectopic expression RhRR1 in Arabidopsis promoted early flowering, accompanied with the less rosette leaf number at bolting, and shorter bolting time after transferring the plants into pots. In addition, the expression of flowering regulatory genes in RhRR1 transgenic Arabidopsis, including FLOWERING LOCUS D, GA REQUIRING 1, LUMINIDEPENDENS, LEAFY, and TWIN SISTER OF FT clearly increased. These results allow us to infer that RhRR1 plays a key role in the control of flowering.
Changing localized environmental conditions along altitude gradients could modify the responses of tree xylem structures to climate variations. To explore how trees adapt to local environment and respond to climate variants, we analysed the variation of Picea meyeri xylem tracheid features and the relationships with climate variables along an altitude gradient (1970, 2240, 2490 and 2650 m above sea level) of the Luyashan Mountains in the North China. The results mainly indicated the following: (1) tracheid number and diameter of P. meyeri showed significant differences among the four sites along the altitude gradient; (2) trees at site 2 (2240 m) and site 3 (2490 m) are similar in age, but the xylem tracheid number and diameter of these trees were significantly different, which may indicate different functional adaptation; (3) the relationships between xylem features' residual chronologies and the monthly climate data were inconsistent along altitude gradients, which indicated that the limiting factor of P. meyeri growth along the altitude gradients, shifted from drought stress at lower altitudes to low-temperature stress at higher altitudes.
An in vitro cumulative gas production technique was used to evaluate the nutritional characteristics of different botanical fractions of mature maize stover (variety Kexiang No.11). Whole maize stover was separated into eight fractions: leaf blade, leaf sheath, whole stem, upper stem, lower stem, cob, husk, and tassel. The results showed that there were significant (P<0.05) variations among different botanical fractions in in vitro gas parameters (e.g., the theoretical maximum volume of gas production, the rate constant of gas production, and fermentation lag time). Husk had the highest theoretical maximum gas production and rate constant, while leaf sheath had the longest lag time. The hemicellulose content was positively related (P<0.05) with cumulative gas production at 24, 36 and 48 h of incubation and with the theoretical maximum gas production. The hemicellulose-to-crude-protein ratio was positively related (P<0.05) to the rate constant of gas production. In vitro gas production showed a negative but not significant (P>0.05) relationship with acid detergent fibre (ADF) and neutral detergent soluble (NDS) contents of the morphological fractions.
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