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Leaf phenology has been considered to evolve to maximize plant carbon gains, and it reflects plant life history strategies. To determine the effect of leaf traits on leaf phenology, leaf emergence (such as timing of leaf emergence, leaf expansion rate, durations of leaf expansion), leaf traits (leaf mass per area – LMA and leaf size), and their relationships were investigated for 40 woody species from 13 families in an evergreen broad-leaved forest, southeast China. Compared with understorey shrubs (23 species), trees species (17 species) were significantly later in timing of leaf emergence, greater in leaf area and leaf expansion rate. This is assumed to be a strategy for large-leaved tree species to decrease damage during leaf expansion. In terms of leaf size, the small-leaved species leafed out earlier than the species with large leaves, but the largeleaved species were greater in leaf expansion rate than their counterparts. Leaf expansion rate was positively correlated with leaf area and timing of leaf emergence. Leaf herbivore rate was positively correlated with leaf area and leaf expansion period, but negatively with LMA. These results suggest that large- and small-leaved species possibly employed different strategies to minimize herbivore damage. Small-leaved species avoid defoliator damage by early leafing, while largeleaved species have shorter expansion times and thereby shorten vulnerable time to herbivores. In general, dynamics of emergence and expansion of the woody species in the study forest indicate that the leaf phenology is of significance for species’ carbon gain and survival.
Eoiocossus validas gen. and sp. nov., a new genus and species belonging to Palaeontinidae (Insecta, Hemiptera), is described from the Middle Jurassic of Daohugou, Inner Mongolia, China. It differs from other genera as follows: large forewing with small clavus, Sc terminating in costal margin beyond the nodus, nodal line along m₄ -cua partly, CuA₂ with two branches and A₂ developed. The ripple-like posterior margin and fresh colour pattern of Eoiocossus may be sex characteristics. The marginal membrane and ambient vein have not distinct evolutionary implications for the Palaeontinidae.
Multivariate statistical techniques, hierarchical cluster analysis (HCA), and principal component analysis (PCA) integrating graphical method (Piper trilinear graphical diagram) were applied to the factor identification of ground water quality in a coastal aquifer, Fujian province, South China. Ground water samples were collected at 12 sites in January (dry season) and July 2011 (wet season). Eleven ground water quality parameters (pH, TH, TDS, Ca²⁺, Mg²⁺, Na⁺ , Cl⁻, SO₄²⁻, HCO₃⁻, NO₃⁻, Mn) were selected in order to perform multivariate statistical analysis. During both the past-monsoon and the summer seasons, PCA results revealed the existence of three significant principal components revealing how processes like salinization, water-rock interaction, and anthropogenic pollution influence ground water quality. Three factors which together explain 90.3% and 83.3% of the total variance in the summer and post-monsoon dataset were retained and interpreted. Cluster analysis using the Ward method with squared Euclidean distance measure was performed, which indicated the distribution of the studied wells according to their water quality. Water samples from 12 wells were clustered into three distinct groups to depict different hydrochemical facies. The results proved that multivariate analysis methods like HCA and PCA could be useful for evaluating ground water pollution and identifying ground water hydrochemistry.
In our previous study, we demonstrated that azurin could selectively trigger apoptosis in human osteosarcoma cell line U2OS cells. However, the rate of apoptosis (35.8 ± 3.2%) is not very high, and azurin is too expensive to obtain readily. To solve these problems, we constructed a eukaryotic expression plasmid containing the azurin gene with an influenza virus haemagglutinin 9 peptide HA epitope tag, and transfected the recombinant plasmid pcDNA3.1(+)/azurin into U2OS cells. RT-PCR and Western blot analysis validated the successful transfection and the expression of the azurin-HA protein. Conspicuous apoptosis of the transfected cells was detected by flow cytometry (FCM) and the DNA ladder test. The apoptosis rate reached 64.3 ± 13.1%. The transcriptional levels of the Bax and p53 genes increased significantly in U2OS cells transfected with pcDNA3.1(+)/azurin, but the Bcl-2 mRNA level decreased. There was no difference in the levels of Bcl-xl mRNA and Survivin mRNA. We propose that the transfection of the recombinant plasmid pcDNA3.1(+)/azurin can significantly induce apoptosis in U2OS cells. This is closely associated with the up-regulation of the transcriptional level of the Bax and p53 genes, and the down-regulation of that of the Bcl-2 gene.
Spatial variability is a major source of uncertainty in estimating the fluxes of greenhouse gases between steppe and atmosphere. The fluxes of CO₂, CH₄, and N₂O were carried out between 08:00 and 10:00 h. of the following day during the midsummer period from a transect (area: 5.25×10⁶ ha) in the semiarid steppe of northern China, using the dark static chamber technique and gas chromatography. Two land uses were chosen for this study: soils with plant covers and bare soils. Daily average GHG fluxes from the steppe transect were: 1.3×10⁵ t C for CO₂, -66.3 t C for CH₄, and 1.1 t N for N₂O. The emission of CO₂ from soils with plant cover was significantly higher (P < 0.05) than that from the corresponding bare soils. The canopy effect, however, was observed for neither CH₄ (P = 0.058) nor N₂O (P = 0.772). Air temperature and relative humidity were the major factors affecting the diurnal variation in site-based CO₂ flux (P < 0.05), while soil pH controlled its spatial variation (P < 0.05). The spatial uptake of CH₄ correlated negatively with soil total N (TN) content (P < 0.05), while the flux of N₂O significantly increased with soil organic carbon (P = 0.031) and TN (P = 0.022), indicating that soil organic matter is an important factor determining the N₂O flux in the steppe of northern China.
The degradation of atrazine (ATZ) by ultraviolet/peroxymonosulfate (UV/PMS) under different conditions was investigated in phosphate buffer, and the degradation mechanism and kinetics were discussed. The results showed that the degradation rate of 2.5 μmol/L ATZ in UV/PMS system was 97.63% in 20 min when the reaction temperature was 20ºC, the concentration of PMS was 20 μmol/L and the UV intensity was 50 mW/cm2 in pH7 phosphate buffer. The mechanism analysis showed that PB with partial alkalinity promoted the degradation of ATZ by UV/PMS more than that with acidic PB. The effect of PB with alkaline conditions on the degradation of ATZ by UV/PMS was more complicated and mainly related to the state of phosphate ions. The UV/PMS system contained both HO• and SO4-•, and the ratio of HO•, SO4-•and UV-degraded ATZ was nearly 1:1 in pH7 PB. Inorganic anions experiments showed that Cl- and HCO3- inhibited the degradation of ATZ under UV/PMS, and the inhibitory effect of Cl- was more obvious. NO3- promoted the degradation of ATZ by UV/PMS. Kinetic analysis showed that UV/PMS degradation of ATZ reaction kinetics was more in line with the quasi first-order reaction kinetics, the inhibition effect of the same concentration of ETA and Clon UV/PMS degradation of ATZ are the same, and UV/PMS degradation of ATZ decreased by 38.54% and 36.29% respectively. The addition of NO3- increased the rate of degradation of ATZ by UV/PMS by 31.21%. By LC-MS analysis, 5 kinds of production m/z and 6 kinds of products were obtained.
It has been shown recently that temporal order perception is modulated by language environments. The present study focused on the specific question whether a secondary language experience influences temporal order perception by comparing the temporal order thresholds (TOTs) between Chinese subjects with and without a secondary non-tonal language (i.e., English) experience. Besides monaurally presented paired clicks, binaurally presented two different types of tone pairs were used in order to better capture a potential difference between tonal and non-tonal languages. The results showed a non-significant language effect on monaurally presented click TOTs, but a significant language effect for binaurally presented tone TOTs. Compared to click performance, Chinese subjects without English proficiency demonstrated a significantly lower TOT only for close frequency tone pairs, while Chinese subjects with English proficiency demonstrated lower TOTs for both close frequency and distant frequency tone pairs. These results confirm on the one hand a common and language independent temporal mechanism for perceiving the order of two monaurally presented stimuli, and indicate on the other hand specific mechanisms of neuronal plasticity for perceiving the order of frequency-related auditory stimuli for tonal language speakers with or without a secondary non-tonal language experience.
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