Wyniki wyszukiwania - Biblioteka Nauki

1

Extremes of order statistics of stationary Gaussian processes

100%

Zhao C.

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tom Vol. 38, Fasc. 1

61--75

EN

Let {Xi(t), t ≥ 0}, 1 ≤ i ≤ n, be mutually independent and identically distributed centered stationary Gaussian processes. Under some mild assumptions on the covariance function, we derive an asymptotic expansion of P [formula] ]X(r) (t) ≤ u) as u → ∞, where mr(u) = (P([formula] X(r) (t) > u))−1 (1 + o(1)), and {X(r) (t), t ≥ 0} is the rth order statistic process of {Xi(t), t ≥ 0}, 1 ≤ i, r ≤ n. As an application of the derived result, we analyze the asymptotics of supremum of the order statistic process of stationary Gaussian processes over random intervals.

2

Intrinsic regulators of OPC activation during CNS remyelination-role of Sox2

100%

Zhao C.

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tom 75

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nr Supl.

EN

Understanding the mechanisms of CNS remyelination is central to developing effective means by which this process can be therapeutically enhanced in chronic demyelinating disease such as multiple sclerosis. Progression of oligodendrocyte progenitor cells (OPCs) to mature oligodendrocytes in response to signals in injury environment holds the key for successful myelin regeneration. Here we discuss the role of Sox2, a transcription factor widely implicated in stem cell biology, in CNS myelination and remyelination. We show that Sox2 is expressed in most OPCs at active period of developmental CNS myelination at early postnatal stage but diminished in adults in oligodendrocyte lineage cells. When demyelinating injury occurs the expression of Sox2 in OPCs is transiently increased but down-regulated upon differentiation. Using genetic fate mapping, gain of function and loss of function experiments, we demonstrated that Sox2 sustains the recruitment of OPCs and its up-regulation is essential for CNS remyelination. These findings suggest that Sox2 and its downstream regulatory factors may play an important role in the activation of OPCs following CNS demyelination and subsequent remyelination.

3

Plasma metabolic differences in cows affected by inactive ovaries or normal ovarian function post partum

51%

Zhao C. , Hu P. , Bai Y. L. , Xia C.

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tom 23

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nr 1

4

Use of fuzzy fault tree analysis and noisy-OR gate bayesian network for navigational risk assessment in Qingzhou Port

51%

Zhao C. , Wu B. , Yip T. L. , Lv J.

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tom Vol. 15 No. 4

765--771

EN

Collisions and groundings account for more than 80% among all types of maritime accidents, and risk assessment is an essential step in the formal safety assessment. This paper proposes a method based on fuzzy fault tree analysis and Noisy-OR gate Bayesian network for navigational risk assessment. First, a fault tree model was established with historical data, and the probability of basic events is calculated using fuzzy sets. Then, the Noisy-OR gate is utilized to determine the conditional probability of related nodes and obtain the probability distribution of the consequences in the Bayesian network. Finally, this proposed method is applied to Qinzhou Port. From sensitivity analysis, several predominant influencing factors are identified, including navigational area, ship type and time of the day. The results indicate that the consequence is sensitive to the position where the accidents occurred. Consequently, this paper provides a practical and reasonable method for risk assessment for navigational accidents.

5

Rotating Speed Identification and Simulation Research of Synchronous Motor based on MRAS

51%

Ren Z. , Li C. , Zhao C.

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tom R. 88, nr 9b

181-183

EN

Rotational speed difference is an important factor that effects synchronism and stability of vibratory machines. This paper establishes the motor dynamical differential equation based on MRAS (model reference adaptive system). Speed regulator is designed based on PID regulator and adaptive controller. Then using MRAS to control, identify and simulate the speed of two rotors. Simulation results show that adopting MRAS is better than common PID system.

PL

W artykule przedstawiono równania różniczkowe opisujące dynamikę silnika synchronicznego bazujące na MRAS (model reference adaptive system). Następnie opracowano system kontroli szybkości bazujący na sterowniku PID i sterowniku adaptacyjnym.

6

Regulation of the expression of lipoxygenase genes in Prunus persica fruit ripening

51%

Han M. , Zhang T. , Zhao C. , Zhi J.

Acta Physiologiae Plantarum

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2011

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tom 33

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nr 4

EN

Three genes of the lipoxygenase (LOX) family in peach (Prunus persica var. compressa cv. Ruipan 4) were cloned, and their expression patterns during fruit ripening were analyzed using real-time quantitative PCR. All of the three peach LOX genes had been expressed during fruit ripening; however, their expression patterns were significantly different. During the normal ripening of peach fruits, the expression levels of PpLox1, PpLox2 and PpLox3 increased in varying degrees accompanying upsurge of ethylene evolution. After treated by methyl jasmonic acid (MeJA), the peak of ethylene releasing occurred in advance, and the declining rate of fruit hardness was accelerated, the expression level of the three peach LOX genes in fruits markedly enhanced at the early stage of storage, but significantly decreased at the late storage stage. So, it could be suggested that all three LOXs relate to fruit ripening; however, their functions might be different. PpLox1 expression increase along with the upsurge of ethylene evolution in both control and MeJAtreated peach fruits suggested that PpLox1 probably played a major role in the peach fruit ripening. Expression peak of PpLox2 appeared at the 1 DAH (days after harvest) in both control and MeJA-treated peach fruits, while obvious changes in ethylene evolution and fruit hardness was not observed, which suggested that the rise of PpLox2 expression can be induced by certain stimulation related to ripening, such as harvesting stress and MeJA treatment. The expression of PpLox3 kept a lower level in the natural ripening fruits, whereas raced up at the early stage of storage in the fruits treated with MeJA, which indicated that PpLox3 was expressed inductively and had minor roles during the normal ripening of peach fruits, but when encountered with external stimulation, its expression level would rapidly enhance and accelerate the ripening of peach fruit.

7

Pyrethroid insecticide effect on platelet biomembranes of rats

51%

Li Q. , Liu X. , Maddu N. , Zhao C.

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nr 1

8

Plasma metabolic differences in cows affected by inactive ovaries or normal ovarian function post partum

45%

Zhao C. , Hu P. , Bai Y. L. , Xia C. , Zhao C. , Hu P. , Bai Y. L. , Xia C.

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nr 1

9

Edge effects on tree growth and species diversity in forests of different types and ages

45%

Li J. , Zhao C. , Peng Y. , Hu Y. , Yuan X.

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nr 3

EN

Edge to interior gradients in forest ecosystems can influence the species composition and community structure as a result of variations in micro-environment. In this study, the edge effects on stand productivity and plant species diversity were investigated in two adjacent types of forests in central-southern China: Chinese fir adjacent with pine forests and Chinese fir adjacent with broad-leaved forests. A total of 48 sample plots for overstory and 240 sample quadrates for understory in different stand ages were set up. The tree growth parameters were measured in the overstory while the plant species diversity was measured in both overstory and understory of the examined forests. The results showed that DBH (tree diameter at the breast height), tree height and stand volume in overstory increased from the central areas (CA) of forests to the edge areas (EA), and the plant species richness and diversity in understory were greater in EA than in CA. The edge effect was greater in Chinese fir paired with broad-leaved forests than in Chinese fir paired with pine forests. The edge effect decreased in an order as young aged stands > middle aged stands > mature aged stands in the studied forests. The changes in tree growth and species diversity in the edge area compared to the interior were mainly attributed to the alteration of micro-environmental factors such as light density, temperature and moisture. Our results suggest increasing forest productivity and plant species diversity could be achieved by making more edges in the forests.

10

Defect solitons supported by kagome photonic lattices in biased photovoltaic-photorefractive crystals

45%

Hui J. , Lu K. , Zhao C. , Gao L. , Chen W.

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tom Vol. 48, nr 3

349--359

EN

We report that defect solitons can be supported by kagome photonic lattices with a defect in biased photovoltaic-photorefractive crystals. For a positive defect, these defect solitons exist only in the semi-infinite bandgap and are stable in the low power region but unstable in the high power region. For a negative defect, these defect solitons exist in both of the semi-infinite bandgaps and the first bandgap. In the semi-infinite bandgap, low-power defect solitons are stable when the negative defect depth is low and unstable when the negative defect depth is high, moderate-power defect solitons are stable when the negative defect depth is high, and high-power defect solitons are unstable for all the negative defect depths. In the first bandgap, defect solitons are stable in all the power regions when the negative defect depth is low. When the negative defect depth is high, defect solitons are stable in the high power region and unstable in the low power region. On the other hand, these defect solitons are those studied previously in kagome photonic lattices with a defect in biased non-photovoltaic-photorefractive crystals when the bulk photovoltaic effect is negligible and those in kagome photonic lattices with a defect in photovoltaic-photorefractive crystals when the external bias field is absent.

11

Features of distribution of uranium and thorium in red mud

45%

Gu H. , Wang N. , Yang Y. , Zhao C. , Cui S.

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tom Vol. 53, iss. 1

110--120

EN

Natural radioactive elements such as uranium and thorium restrict the use of red mud as building materials or additives, and may cause environmental problems. The distribution features of U and Th in red mud was studied from micro and macro analysis, using EPMA, LA-ICP-MS, and methods of mineralogy and beneficiation. Based on the micro-area scanning analysis, main chemical compositions in red mud, such as Ca, Al, Si, Na, and K are dispersive while Fe and Ti mainly tend to concentrate in granular phases. Based on the in-situ analysis, the distribution of main elements and most trace elements in micro-zone of red mud was homogeneous. In micro-zone area, the variation tendency of thorium content was similar with Y in red mud samples. By means of the methods of mineralogy and beneficiation, red mud samples were separated into different fractions. U and Th tend to be enriched in the low density fraction of the red mud. Th presented a high concentration in the finest particle size fractions of the red mud. Neither U or Th was regularly distributed in various magnetic red mud fractions. Thorium fingerprint peaks were determined in perovskite by EDX under TEM, which is proposed to be one of the radioactivity sources in Bayer red mud.

12

Edge Effects on Tree Growth and Species Diversity in Forests of Different Types and Ages

45%

Li J. , Zhao C. , Peng Y. , Hu Y. , Yuan X.

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tom Vol. 66, nr 3

239--249

EN

Edge to interior gradients in forest ecosystems can influence the species composition and community structure as a result of variations in micro-environment. In this study, the edge effects on stand productivity and plant species diversity were investigated in two adjacent types of forests in central-southern China: Chinese fir adjacent with pine forests and Chinese fir adjacent with broad-leaved forests. A total of 48 sample plots for overstory and 240 sample quadrates for understory in different stand ages were set up. The tree growth parameters were measured in the overstory while the plant species diversity was measured in both overstory and understory of the examined forests. The results showed that DBH (tree diameter at the breast height), tree height and stand volume in overstory increased from the central areas (CA) of forests to the edge areas (EA), and the plant species richness and diversity in understory were greater in EA than in CA. The edge effect was greater in Chinese fir paired with broad-leaved forests than in Chinese fir paired with pine forests. The edge effect decreased in an order as young aged stands > middle aged stands > mature aged stands in the studied forests. The changes in tree growth and species diversity in the edge area compared to the interior were mainly attributed to the alteration of micro-environmental factors such as light density, temperature and moisture. Our results suggest increasing forest productivity and plant species diversity could be achieved by making more edges in the forests.

13

An orthogonal test of the effect of NO3−, PO43−, K+, and Ca2+ on the growth and ion absorption of Elaeagnus angustifolia L. seedlings under salt stress

38%

Li L. , Zhu T. , Liu J. , Zhao C. , Li L. , Chen M.

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2019

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tom 41

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nr 11

EN

Excess salts in soil severely inhibit plant growth and yield. Various nutrients can relieve the inhibitory effect of salt on plants. Elaeagnus angustifolia is a tree species that is utilized in landscaping and ecological restoration in China and shows tolerance to saline soils. In this experiment, we first determined the optimal concentration of single-nutrient inputs for promoting growth of E. angustifolia seedlings and alleviating salt stress. The optimal nitrogen (NO₃⁻), phosphorus (PO₄³ ⁻), potassium (K⁺ ), and calcium (Ca²⁺ ) concentrations under salt stress were 2, 0.6, 2, and 2 mM, respectively. Based on this result, we carried out an optimum nutrient ratio experiment by a four-factor and three-level orthogonal experiment. The results showed that under normal growth conditions, the optimal nutrient combinations for NO₃⁻, PO₄³ ⁻, K⁺ , and Ca²⁺ were 2, 0.6, 5, and 1 mM; 5, 0.2, 5, and 2 mM; and 5, 0.6, 1, and 5 mM, respectively, which increased plant height, biomass, and the chlorophyll content of E. angustifolia seedlings. Under salt stress, the optimal nutrient combinations were 5, 0.2, 5, and 2 mM; and 5, 0.6, 1, and 5 mM, respectively. This study provides a theoretical basis for optimal fertilization of E. angustifolia seedlings in saline-alkali soils.

14

Plasma metabolic characterisation of dairy cows with inactive ovaries and oestrus during the peak of lactation

38%

Song Y. X. , Hu P. , Bai Y. L. , Zhao C. , Xia C. , Xu C.

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tom 63

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nr 3

15

Functional traits related to environmental divergence in combination with phylogenetic relationship of Picea species

38%

Wang M. , Wang J. , Zhang A. , Zhang X. , Sun S. , Zhao C.

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2018

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tom 80

16

Soil nematode trophic groups in four different plantations in southern China: implications for restoration

32%

Zhao C. , Sun F. , Yu C. , Zhu L. , Li Y. , Zhou Z. , Yang G. , Wang W. , Miao R.

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nr 3

EN

Intensive anthropogenic disturbances have caused forest ecosystem degradation and soil erosion. Exotic fast-growing species are selected as pioneer species for restoration in degraded hilly lands of southern China. To better understand the potentials of the soil nematode trophic group composition in carbon sequestration, we investigated nematode trophic groups in Acacia, Eucalyptus, and Schima (native species as control) monoculture plantations in southern China after 23 years of reforestation. Our results showed that although total soil nematode abundance was not affected, the Acacia plantation significantly altered nematode trophic group composition over native species. Bacterivore and microbivore abundance, trophic diversity, and microbivore-driven soil organic carbon storage were higher in Acacia mangium than Schima superba. In contrast, plant parasitic nematode abundance and fungivore/bacterivore ratio were lower in Acacia mangium than Schima superba. As a result, Acacia mangium as a fast-growing pioneer tree species could be widely planted to maintain soil biodiversity and store carbon in restoring degraded forests in southern China. Eucalyptus exserta plantation enlarged the soil nematode community, including bacterivores, fungivores, and herbivores, suggesting that there is almost no allelopathy when eliminating anthropogenic disturbance in this study. Reasonable management is crucial for providing timber products and improving the ecological function of Eucalyptus plantations. Our results also highlight the critical roles of soil water and nutrient availability in regulating soil nematode trophic group composition and carbon sequestration.

17

Foliar responses of Abie fargesii Franch. To altitude in the Taibai Mts, China

32%

Xu P. , Zhang X. , Zhao C. , Chen L. , Gao X. , Yao B. , Deng J. , Deng Y.

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2014

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tom Vol. 62, nr 3

479--492

EN

Physiological and ecological adaptations of altitudinal gradients reveal alpine plants’ ecological and evolutionary responses to environmental changes. Here we quantitatively investigated the variation in the foliar physiological and morphological traits of alpine tree species (Abies fargesii) along the altitudinal gradient in the Taibai Mountains, China. We collected the needle samples of Taibai fir (A. fargesii) from seven sites at altitudes of 2550, 2650, 2750, 2850, 2950, 3050 and 3150 m, respectively, and measured the 12 foliar physiological and morphological traits. Each set of needle sample (100 needles) was randomly selected from the upper- third of A. fargesii canopies. The results showed that leaf mass per unit area (LMA), stable carbon isotope composition (δ13C), stomatal rows (SR), leaf carbon concentration per unit area (Carea), leaf nitrogen concentration per unit leaf mass (Nmass) and area (Narea) linearly increase significantly while stomatal density (SD), number of stomata per unit nitrogen concentration (St/N) and per unit leaf mass (St/LM) decrease with the altitudes raise. Moreover, all measured traits presented both strong correlations and significantly linear relationships with the main climate factors such as the mean temperature, rainfall and relative humidity during the growing season as well as the altitudes, except for leaf free water concentration (LWC), leaf carbon concentration per unit leaf mass (Cmass) and C: N ratio. The patterns of foliar traits in response to altitudes imply that the alpine plants need higher cost (e.g. higher nutrient concentration) to adapt to the harsher environments along altitudinal gradient. Moreover, our results show that the variation patterns of the leaf traits for A. fargesii plants should be driven by the interactions of multi-climate factors because the abiotic factors that directly influence the growth of plants covary with the increasing altitudes.

18

Foliar responses of Abie fargesii Franch. to altitude in the Taibai Mts, China

32%

Xu P. , Zhang X. , Zhao C. , Chen L. , Gao X. , Yao B. , Deng J. , Deng Y.

Polish Journal of Ecology

|

2014

|

tom 62

|

nr 3

EN

Physiological and ecological adaptations of altitudinal gradients reveal alpine plants’ ecological and evolutionary responses to environmental changes. Here we quantitatively investigated the variation in the foliar physiological and morphological traits of alpine tree species (Abies fargesii) along the altitudinal gradient in the Taibai Mountains, China. We collected the needle samples of Taibai fir (A. fargesii) from seven sites at altitudes of 2550, 2650, 2750, 2850, 2950, 3050 and 3150 m, respectively, and measured the 12 foliar physiological and morphological traits. Each set of needle sample (100 needles) was randomly selected from the upper- third of A. fargesii canopies. The results showed that leaf mass per unit area (LMA), stable carbon isotope composition (δ13C), stomatal rows (SR), leaf carbon concentration per unit area (Carea), leaf nitrogen concentration per unit leaf mass (Nmass) and area (Narea) linearly increase significantly while stomatal density (SD), number of stomata per unit nitrogen concentration (St/N) and per unit leaf mass (St/LM) decrease with the altitudes raise. Moreover, all measured traits presented both strong correlations and significantly linear relationships with the main climate factors such as the mean temperature, rainfall and relative humidity during the growing season as well as the altitudes, except for leaf free water concentration (LWC), leaf carbon concentration per unit leaf mass (Cmass) and C: N ratio. The patterns of foliar traits in response to altitudes imply that the alpine plants need higher cost (e.g. higher nutrient concentration) to adapt to the harsher environments along altitudinal gradient. Moreover, our results show that the variation patterns of the leaf traits for A. fargesii plants should be driven by the interactions of multi-climate factors because the abiotic factors that directly influence the growth of plants covary with the increasing altitudes.

19

Evolution and driving forces of non-point source pollution in a developing megacity: Beijing as a long-term case study

32%

Lou H. , Yang S. , Hao F. , Ren X. , Zhao C. , Wang Y. , Lei T. , Sun F.

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nr 1