Soil samples were taken from rhizosphere zone and off-rhizosphere zone of ash (Fraxinus mandshurica Rupr.) and larch (Larix olgensis Henry) in mixed and monoculture stands, and the nutrient concentration of N, P, and ...Soil samples were taken from rhizosphere zone and off-rhizosphere zone of ash (Fraxinus mandshurica Rupr.) and larch (Larix olgensis Henry) in mixed and monoculture stands, and the nutrient concentration of N, P, and K was analyzed to study the effect of nutrients variation on yield improvement in the mixed stand. The result showed that: 1) The stand level total soil N concentration and available N in the mixed stand was similar to that in the monoculture stand of ash, but higher than that in monoculture stand of larch. The total N and available N concentration in rhizosphere soil of ash in the mixed stand was similar to that in the monoculture stand of ash, but the available N concentration in rhizosphere of larch in mixed stand was much higher than in its monoculture. 2) The stand level total P, total K concentration in the mixed stand was similar to that in monocul-ture stands of both species, but available P and K was more concentrated in the mixed stand than in the monoculture stands of ash. The rhizosphere available P and K of ash in the mixed stand was 44.1% and 13.5% (for the 9-yr-old stands) and 79.6% and 25.6% (for the 21-yr-old stands) higher than that in its monoculture. The improvement of soil P and K availability in the mixed stand is concluded.展开更多
The spatial distribution of standing fine roots in tree rows of different species in a 12-year-old mixed stand of ash (Fraxinus mandshurica Rupr.) and larch (Larix olgensis Henry) was studied by soil core sampling in ...The spatial distribution of standing fine roots in tree rows of different species in a 12-year-old mixed stand of ash (Fraxinus mandshurica Rupr.) and larch (Larix olgensis Henry) was studied by soil core sampling in early spring, 2001. It is found that ash and larch differ greatly in their belowground biomass distribution. Ash has much higher fine root biomass density in the soil than larch at stand level (with the max value of 4442.3 vs. 2234.9 gm-3). Both tree species deployed more fine roots in their neighboring zone, suggesting a less intensive competition between roots of the two species. Both fine root biomass density and root length density of ash in the zone between larch tree rows are greater than that of larch in zone between ash tree rows, indicating that ash is more powerful than larch in belowground competition. The spatial distribution feature of roots favors the growth of ash in the mixed stand.展开更多
From September 1999 to July 2000, N and P concentrations of fine roots were measured with the method of sequential soil core at bimonthly intervals in a mixed forest of Tsoong's tree (Tsoongiodendron odorum Chun) ...From September 1999 to July 2000, N and P concentrations of fine roots were measured with the method of sequential soil core at bimonthly intervals in a mixed forest of Tsoong's tree (Tsoongiodendron odorum Chun) and Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) in Sanming, Fujian. The results showed that N, P concentration of Chinese fir and Tsoong's tree in fine roots were negatively related to root diameter size. The concentrations of N and P in living roots and dead roots were compared. The order of N concentration in fine roots in different samples was Tsoong's tree>undergrowth>Chinese fir, while that of P was undergrowth>Tsoong's tree>Chinese fir. For Chinese fir, the seasonal change of N, P concentrations in fine roots with various diameter classes showed a single-apex curve with a maximum in September. For Tsoong's tree, maximized concentration of N in fine roots appeared in July or September and maximized P concentration in May.展开更多
The interaction of Pb Cd can be observed not only in the uptake process of elements by plants and in their influence on the growth, but also in rhizosphere. The changes in extractable Cd and Pb concentrations in the ...The interaction of Pb Cd can be observed not only in the uptake process of elements by plants and in their influence on the growth, but also in rhizosphere. The changes in extractable Cd and Pb concentrations in the rhizosphere soil of rice plants, root exudates from wheat and wheat plant and their complexing capacity with Pb and Cd were investigated under different Pb and Cd treatments. Results showed that the concentration of extractable Cd in the rhizosphere of rice in red soil was markedly increased by Pb Cd interaction. It increased by 56% in the treatment with Pb and Cd added against that in the treatment with only Cd added in soil. The considerable differences in both composition and amount of root exudate from wheat and rice were found among different treatments. Pb and Cd might be complexed by root exudates. The concentrations of free Pb and Cd in the solution were increased markedly by adding root exudate from wheat and decreased by that from rice due to Pb Cd interaction. The distribution patterns of Pb and Cd in roots were affected by Pb Cd interaction, which accelerated transport of Pb into internal tissue and retarded accumulation of Cd in external tissue.展开更多
Under conditions of a warmer climate,the advance of the alpine treeline into alpine tundra has implications for carbon dynamics in mountain ecosystems.However,the above- and below-ground live biomass allocations among...Under conditions of a warmer climate,the advance of the alpine treeline into alpine tundra has implications for carbon dynamics in mountain ecosystems.However,the above- and below-ground live biomass allocations among different vegetation types within the treeline ecotones are not well investigated.To determine the altitudinal patterns of above-/below-ground carbon allocation,we measured the root biomass and estimated the above-ground biomass(AGB) in a subalpine forest,treeline forest,alpine shrub,and alpine grassland along two elevational transects towards the alpine tundra in southeast Tibet.The AGB strongly declined with increasing elevation,which was associated with a decrease in the leaf area index and a consequent reduction in carbon gain.The fine root biomass(FRB) increased significantly more in the alpine shrub and grassland than in the treeline forest,whereas the coarse root biomass changed little with increasing altitudes,which led to a stable below-ground biomass(BGB) value across altitudes.Warm and infertile soil conditions might explain the large amount of FRB in alpine shrub and grassland.Consequently,the root toshoot biomass ratio increased sharply with altitude,which suggested a remarkable shift of biomass allocation to root systems near the alpine tundra.Our findings demonstrate contrasting changes in AGB and BGB allocations across treeline ecotones,which should be considered when estimating carbon dynamics with shifting treelines.展开更多
Root box experiments were conducted to evaluate the effects of N and NK levels in the root zone on shoot photosynthesis and root growth of hybrid and cultivar of rice (Oryza sativa L.) on two paddy soils (clayey and s...Root box experiments were conducted to evaluate the effects of N and NK levels in the root zone on shoot photosynthesis and root growth of hybrid and cultivar of rice (Oryza sativa L.) on two paddy soils (clayey and silty). The results showed that dry matter yields in the hybrid and the cultivar were considerably increased by NK supply, but the effect was greater for the hybrid. Supply of NK in the root zone significantly increased photosynthetic rate of the lower position leaf and the active green leaf area per plant, in which the effects were much more obvious in the hybrid rice than in the cultivar. High NK supply in the root zone stimulated the root growth, and decreased PH and increased the oxidation zone in the rhizosphere in both entries, but to a greater extent in the hybrid. The results indicated that higher NK levels were needed to maintain higher root activity and shoot photosynthetic capacity in rice, particularly in hybrid rice.展开更多
To study the physiological effects of small root zonel plants of a hybrid wheat variety (Triticum aestivnmL.cv. Meiyou 4) were grown in small pots (1 litre) or large pots (8 litre) with 1ow nitrogen (50 mg kg-1 soil)a...To study the physiological effects of small root zonel plants of a hybrid wheat variety (Triticum aestivnmL.cv. Meiyou 4) were grown in small pots (1 litre) or large pots (8 litre) with 1ow nitrogen (50 mg kg-1 soil)and high nitrogen (200 mg kg-1 soil). Restricting root zone decreased dry weight of plants at the stages ofstem elongation and flowering, compared to those of control plants grown in the large pots (P<0.01). Sprayingof 6-benzylaminopurine (50 μmol L-1) increased dry weight of plants and chlorop hyll concentration in leaves.Restriction of root zone decreased the concentrations of total nitrogen, chlorophyll and soluble protein in thefiag leaf and acce1erated senescence of the leaves. Supply of high nitrogen delayed senescence of the fiag leafThe results suggested that the shortage of nutrients, especially nitrogen deficiency was the primary reasonfor the decreased growth of plant in the treatment of root zone restriction.展开更多
Lalo Classic Opera The King Duration:April 3rd-April 6th,2008 Avenue:National Grand Theater-Opera House Ticket Price:R MB 180/380/580/880/1080/1380 Performer:Theatre National de Toulouse of France Composer:Edouard Lal...Lalo Classic Opera The King Duration:April 3rd-April 6th,2008 Avenue:National Grand Theater-Opera House Ticket Price:R MB 180/380/580/880/1080/1380 Performer:Theatre National de Toulouse of France Composer:Edouard Lalo(French) Conductor:Michel Plasson(French) Edouard Lalo composed for a wide variety of forms, including stage,symphony orchestra,and chamber music. Unfortunately,his stature outside his homeland rests almost entirely on one spectacular violin showpiece,the Symphonie Espagnole.Within France,however,he is noted for his other works as well,including a single operatic masterpiece'Le Roi D'Ys'(the King of the legendary city of Ys).Lalo himself considered this work to be his greatest work.展开更多
Burkitt＇s lymphoma is a highly aggressive non-Hodgkin lymphoma, often presenting in extra-nodal sites. It generally has a poor spontaneous outcome and needs aggressive treatment with systemic and intrathecal chemothe...Burkitt＇s lymphoma is a highly aggressive non-Hodgkin lymphoma, often presenting in extra-nodal sites. It generally has a poor spontaneous outcome and needs aggressive treatment with systemic and intrathecal chemotherapy. Occurrence at the gastric site is rare. We report the case of a 39-year old woman who presented with a prominent ulcerated lesion of the antrum corresponding histologically to a Burkitt＇s lymphoma associated with He/icobacter py/ori （H pylori） infection. Interphase fluorescence in situ hybridization （FISH） demonstrated c-MYC gene rearrangement in tumour cells without BCL2 or BCL6 gene translocations. Ulcer healing and tumour regression with a complete histological response were obtained 8 wk after Hpylori eradication. In spite of this complete remission, taking into account the high risk of recurrence, the patient received systemic and intrathecal chemotherapy. Two years later, the patient remained in complete remission. This is the first report of a gastric Burkitt＇s lymphoma responding to Hpylori eradication. These findings raise the question of the potential role of H pylori in the pathogenesis of some gastric Burkitt＇s lymphomas, and show the importance of searching for and eradicating the bacteria in combination with conventional chemotherapy regimens.展开更多
Thirty bloomed hybrids of C. azalea were selected to have been studied. Of them, 10 cross-combinations were included. The results showed that the hybrids were consistently tended to C. azalea on flower bud formation a...Thirty bloomed hybrids of C. azalea were selected to have been studied. Of them, 10 cross-combinations were included. The results showed that the hybrids were consistently tended to C. azalea on flower bud formation and development, blooming period, leaf trait and plant growth, but flower color, flower form and flower size of the hybrids, in a great degree, were dependent on the traits of another non-C, azalea＇s cross-parent. The hybrids all can bloom from summer to December and even to next spring. The hybrids＇ photographs illustrated in the paper show that their flowers are beautiful with different color, form and size. Also some of genetic laws of C. azalea＇s hybrids were discussed. These fire-new hybrids firstly fill the blank that no camellia flowers can be enjoyed in summer in the world.展开更多
Dynamics of ammonium and ammonia in solutions is closely related to the metabolism of arnrnoniac compounds, therefore plays an important role in various biological processes. NMR measurements indicated that the reorie...Dynamics of ammonium and ammonia in solutions is closely related to the metabolism of arnrnoniac compounds, therefore plays an important role in various biological processes. NMR measurements indicated that the reorientation dynamics of NH4＋ is faster in its aqueous solution than in rnethanol, which deviates from the Stokes-Einstein-Debye rule since water has higher viscosity than methanol. To address this intriguing issue, we herein study the reorientation dynamics of ammonium ion in both solutions using numerical simulation and an extended cyclic Markov chain model. An evident decoupling between translation and ro- tation of methanol is observed in simulation, which results in the deviation of reorientation from the Stokes-Einstein-Debye rule. Slower hydrogen bond （HB） switchings of ammonium with rnethanol comparing to that with water, due to the steric effect of the rnethyl group, remarkably retards the jump rotation of ammonium. The observations herein provide useful insights into the dynamic behavior of ammonium in the heterogeneous environments including the protein surface or protein channels.展开更多
The role of mycorrhizal symbiosis in the alleviation of salinity stress induced by sodium chloride （NaCI） was investigated. Three artichoke hybrids, Madrigal F1, Opal FI, and Concerto FI （Nunhems company）, were gr...The role of mycorrhizal symbiosis in the alleviation of salinity stress induced by sodium chloride （NaCI） was investigated. Three artichoke hybrids, Madrigal F1, Opal FI, and Concerto FI （Nunhems company）, were grown in pot in controlled environment with two different mycorrhizal treatments （with or without Glomus viscosum）. Two months after inoculation, the fungus established well on roots of the Madrigal and Opal plants with higher colonization and dependency values, instead the Concerto plants showed lower mycorrhizal dependency and colonization rate. Mycorrhizal symbiosis generally improved plant vegetative growth and sustained plant physiology increasing stomatal conductance and SPAD values. The root systems of two months old artichoke plantlets, both inoculated and non inoculated, were placed in distilled water enriched with different salt concentrations （0, 100, 150, 200, 250 mM NaCI） to study the wilting response. A visual rating system was developed defining various wilting indexes （TO, no wilting; T1, foliar damage on less than 50% of vegetal tissues of basal leaves; T2, initial wilting and foliar damage on more than 50% of vegetal tissues of basal leaves; T3, foliar damage on the apical leaves; and T4, total wilting）. Mycorrhizal plants reached later the wilting indexes than non-mycorrhizal plants. Electrolyte leakage by leaves after salinity imposition was higher in non-mycorrhizal plants and the vegetal tissues were severely damaged especially in the basal leaves. The greater tolerance observed in the mycorrhizal plants could be in agreement with the improvement in growth stimulated by mycorrhizal symbiosis, which leads to the dilution of toxic ions.展开更多
In this paper, vector autoregressive （VAR） models have been recognized for the selected indicators of Dhaka stock exchange （DSE）. Bangladesh uses the micro economic variables, such as stock trade, invested stock c...In this paper, vector autoregressive （VAR） models have been recognized for the selected indicators of Dhaka stock exchange （DSE）. Bangladesh uses the micro economic variables, such as stock trade, invested stock capital, stock volume, current market value, and DSE general indexes which have the direct impact on DSE prices. The data were collected for the period from June 2004 to July 2013 as the basis on daily scale. But to get the maximum explorative information and reduction of volatility, the data have been transformed to the monthly scale. The outliers and extreme values of the study variables are detected through box and whisker plot. To detect the unit root property of the study variables, various unit root tests have been applied. The forecast performance of the different VAR models is compared to have the minimum residual. Moreover, the dynamics of this financial market is analyzed through Granger causality and impulse response analysis.展开更多
Concession contracts in highways often include some kind of clauses （for example, a minimum traffic guarantee） that allow for better management of the business risks. The value of these clauses may be important and ...Concession contracts in highways often include some kind of clauses （for example, a minimum traffic guarantee） that allow for better management of the business risks. The value of these clauses may be important and should be added to the total value of the concession. However, in these cases, traditional valuation techniques, like the NPV （net present value） of the project, are insufficient. An alternative methodology for the valuation of highway concession is one based on the real options approach. This methodology is generally built on the assumption of the evolution of traffic volume as a GBM （geometric Brownian motion）, which is the hypothesis analyzed in this paper. First, a description of the methodology used for the analysis of the existence of unit roots （i.e., the hypothesis of non-stationarity） is provided. The Dickey-Fuller approach has been used, which is the most common test for this kind of analysis. Then this methodology is applied to perform a statistical analysis of traffic series in Spanish toll highways. For this purpose, data on the AADT （annual average daily traffic） on a set of highways have been used. The period of analysis is around thirty years in most cases. The main outcome of the research is that the hypothesis that traffic volume follows a GBM process in Spanish toll highways cannot be rejected. This result is robust, and therefore it can be used as a starting point for the application of the real options theory to assess toll highway concessions.展开更多
In the city of La Plata （Argentina） and the surroundings, there are tomato landraces, widely known as ＂tomate platense＂ and particularly prized because of their flavor. The objective was to evaluate seven promisso...In the city of La Plata （Argentina） and the surroundings, there are tomato landraces, widely known as ＂tomate platense＂ and particularly prized because of their flavor. The objective was to evaluate seven promissory lines of ＂tomate platense＂ （TL） derived from local varieties and a commercial hybrid （CH） considering yield, fruit characters and their possible associations. Nine plants per treatment were arranged in a randomized complete block design （r = 4）. The following parameters were determined： diameter （cm）, height （cm）, diameter/height （D/H） ratio, weight per fruit （g）, number of locules, the average number of fruits per plant, the average weight of fruits per plant （kg/ptant）, the yield （ton/ha） and the survival percentage. ANOVA, Tukey＇s test and Pearson correlation coefficient were applied. The TL showed greater （P ≤ 0.01） diameter, D/H ratio and number of locules than CH. In all materials, both diameter and height were associated （P ≤ 0.05） with the weight per fruit. Six of TL had greater （P ≤ 0.01） weight per fruit than HC. Respect to number of fruits per plant, weight of fruits per plant and yield, there were no significant differences among the materials. The survival for CH was lower （P ≤0.05） than that for TL. Although fruits with a smaller size and less flattened have been selected, the lines show enough similarity in these characters that identified their common origin. With the fruits smaller and more uniform, and having no joined fruits, these lines may be of interest to be cultivated under low-input system conditions and practical for low-income producers.展开更多
This paper aims to examine the existence of calendar anomalies including month-of-year effect, turn-of-month effect, and weekend effect in Thai stock market. The stock return is computed from SET index during 1988 to ...This paper aims to examine the existence of calendar anomalies including month-of-year effect, turn-of-month effect, and weekend effect in Thai stock market. The stock return is computed from SET index during 1988 to 2009 and the SET50 index gathered since it was created in 1995. The unit root test is performed to ensure that the stock return series have no unit root. The multiple regression techniques using dummy variables are employed to test the difference of the return during each calendar anomalies period. If the regression model suffers from conditional heteroskedasticity, the GARCH （1, 1） model will be used instead of normal ordinary least square regression. It was found that the calendar anomalies exist in Thai stock market. The return is abnormally high during December and January, which can be addressed to be the turn-of-year effect. The return during the turn-of-month period, which can be defined as the last trading day and the first four trading days of the following months, is also abnormally high. Finally, the return is also abnormally high on Fridays but abnormally low on Mondays, which is addressed as weekend effect. This may create the opportunity to make above-average profit to investors exploiting these calendar anomalies. Although these calendar anomalies may be difficult to be exploited in practice because of transaction costs and ability to replicate the stock index, the existing evidence of calendar anomalies can help investors as the clue for the timing of investment.展开更多
In this paper, we present a novel geometric method for efficiently and robustly computing intersections between a ray and a triangular Bezier patch defined over a triangular domain, called the hybrid clipping （HC） a...In this paper, we present a novel geometric method for efficiently and robustly computing intersections between a ray and a triangular Bezier patch defined over a triangular domain, called the hybrid clipping （HC） algorithm. If the ray pierces the patch only once, we locate the parametric value of the intersection to a smaller triangular domain, which is determined by pairs of lines and quadratic curves, by using a multi-degree reduction method. The triangular domain is iteratively clipped into a smaller one by combining a subdivision method, until the domain size reaches a prespecified threshold. When the ray intersects the patch more than once, Descartes＇ rule of signs and a split step are required to isolate the intersection points. The algorithm can be proven to clip the triangular domain with a cubic convergence rate after an appropriate preprocessing procedure. The proposed algorithm has many attractive properties, such as the absence of an initial guess and insensitivity to small changes in coefficients of the original problem. Experiments have been conducted to illustrate the efficacy of our method in solving ray-triangular Bezier patch intersection problems.展开更多
基金This study was supported by National Natural Science Foundation of China (Grant No. 30130160) and the Quick Response of Basic Research Supporting Program (Grant No.2102)
文摘Soil samples were taken from rhizosphere zone and off-rhizosphere zone of ash (Fraxinus mandshurica Rupr.) and larch (Larix olgensis Henry) in mixed and monoculture stands, and the nutrient concentration of N, P, and K was analyzed to study the effect of nutrients variation on yield improvement in the mixed stand. The result showed that: 1) The stand level total soil N concentration and available N in the mixed stand was similar to that in the monoculture stand of ash, but higher than that in monoculture stand of larch. The total N and available N concentration in rhizosphere soil of ash in the mixed stand was similar to that in the monoculture stand of ash, but the available N concentration in rhizosphere of larch in mixed stand was much higher than in its monoculture. 2) The stand level total P, total K concentration in the mixed stand was similar to that in monocul-ture stands of both species, but available P and K was more concentrated in the mixed stand than in the monoculture stands of ash. The rhizosphere available P and K of ash in the mixed stand was 44.1% and 13.5% (for the 9-yr-old stands) and 79.6% and 25.6% (for the 21-yr-old stands) higher than that in its monoculture. The improvement of soil P and K availability in the mixed stand is concluded.
基金This study was supported by National Natural Science Foundation of China (Grant No. 30130160) and the Quick Response of Basic Research Supporting Program (Grant No.2102)
文摘The spatial distribution of standing fine roots in tree rows of different species in a 12-year-old mixed stand of ash (Fraxinus mandshurica Rupr.) and larch (Larix olgensis Henry) was studied by soil core sampling in early spring, 2001. It is found that ash and larch differ greatly in their belowground biomass distribution. Ash has much higher fine root biomass density in the soil than larch at stand level (with the max value of 4442.3 vs. 2234.9 gm-3). Both tree species deployed more fine roots in their neighboring zone, suggesting a less intensive competition between roots of the two species. Both fine root biomass density and root length density of ash in the zone between larch tree rows are greater than that of larch in zone between ash tree rows, indicating that ash is more powerful than larch in belowground competition. The spatial distribution feature of roots favors the growth of ash in the mixed stand.
基金The Foundation of Post-doctoral Research of China (1999, No 10), the Foundation for University Key Teacher by the Ministry of Ed
文摘From September 1999 to July 2000, N and P concentrations of fine roots were measured with the method of sequential soil core at bimonthly intervals in a mixed forest of Tsoong's tree (Tsoongiodendron odorum Chun) and Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) in Sanming, Fujian. The results showed that N, P concentration of Chinese fir and Tsoong's tree in fine roots were negatively related to root diameter size. The concentrations of N and P in living roots and dead roots were compared. The order of N concentration in fine roots in different samples was Tsoong's tree>undergrowth>Chinese fir, while that of P was undergrowth>Tsoong's tree>Chinese fir. For Chinese fir, the seasonal change of N, P concentrations in fine roots with various diameter classes showed a single-apex curve with a maximum in September. For Tsoong's tree, maximized concentration of N in fine roots appeared in July or September and maximized P concentration in May.
文摘The interaction of Pb Cd can be observed not only in the uptake process of elements by plants and in their influence on the growth, but also in rhizosphere. The changes in extractable Cd and Pb concentrations in the rhizosphere soil of rice plants, root exudates from wheat and wheat plant and their complexing capacity with Pb and Cd were investigated under different Pb and Cd treatments. Results showed that the concentration of extractable Cd in the rhizosphere of rice in red soil was markedly increased by Pb Cd interaction. It increased by 56% in the treatment with Pb and Cd added against that in the treatment with only Cd added in soil. The considerable differences in both composition and amount of root exudate from wheat and rice were found among different treatments. Pb and Cd might be complexed by root exudates. The concentrations of free Pb and Cd in the solution were increased markedly by adding root exudate from wheat and decreased by that from rice due to Pb Cd interaction. The distribution patterns of Pb and Cd in roots were affected by Pb Cd interaction, which accelerated transport of Pb into internal tissue and retarded accumulation of Cd in external tissue.
基金supported by the National Natural Science Foundation of China (41561011)the Natural Science Foundation of Jiangxi Province, China (20151BAB213029)
文摘Under conditions of a warmer climate,the advance of the alpine treeline into alpine tundra has implications for carbon dynamics in mountain ecosystems.However,the above- and below-ground live biomass allocations among different vegetation types within the treeline ecotones are not well investigated.To determine the altitudinal patterns of above-/below-ground carbon allocation,we measured the root biomass and estimated the above-ground biomass(AGB) in a subalpine forest,treeline forest,alpine shrub,and alpine grassland along two elevational transects towards the alpine tundra in southeast Tibet.The AGB strongly declined with increasing elevation,which was associated with a decrease in the leaf area index and a consequent reduction in carbon gain.The fine root biomass(FRB) increased significantly more in the alpine shrub and grassland than in the treeline forest,whereas the coarse root biomass changed little with increasing altitudes,which led to a stable below-ground biomass(BGB) value across altitudes.Warm and infertile soil conditions might explain the large amount of FRB in alpine shrub and grassland.Consequently,the root toshoot biomass ratio increased sharply with altitude,which suggested a remarkable shift of biomass allocation to root systems near the alpine tundra.Our findings demonstrate contrasting changes in AGB and BGB allocations across treeline ecotones,which should be considered when estimating carbon dynamics with shifting treelines.
文摘Root box experiments were conducted to evaluate the effects of N and NK levels in the root zone on shoot photosynthesis and root growth of hybrid and cultivar of rice (Oryza sativa L.) on two paddy soils (clayey and silty). The results showed that dry matter yields in the hybrid and the cultivar were considerably increased by NK supply, but the effect was greater for the hybrid. Supply of NK in the root zone significantly increased photosynthetic rate of the lower position leaf and the active green leaf area per plant, in which the effects were much more obvious in the hybrid rice than in the cultivar. High NK supply in the root zone stimulated the root growth, and decreased PH and increased the oxidation zone in the rhizosphere in both entries, but to a greater extent in the hybrid. The results indicated that higher NK levels were needed to maintain higher root activity and shoot photosynthetic capacity in rice, particularly in hybrid rice.
文摘To study the physiological effects of small root zonel plants of a hybrid wheat variety (Triticum aestivnmL.cv. Meiyou 4) were grown in small pots (1 litre) or large pots (8 litre) with 1ow nitrogen (50 mg kg-1 soil)and high nitrogen (200 mg kg-1 soil). Restricting root zone decreased dry weight of plants at the stages ofstem elongation and flowering, compared to those of control plants grown in the large pots (P<0.01). Sprayingof 6-benzylaminopurine (50 μmol L-1) increased dry weight of plants and chlorop hyll concentration in leaves.Restriction of root zone decreased the concentrations of total nitrogen, chlorophyll and soluble protein in thefiag leaf and acce1erated senescence of the leaves. Supply of high nitrogen delayed senescence of the fiag leafThe results suggested that the shortage of nutrients, especially nitrogen deficiency was the primary reasonfor the decreased growth of plant in the treatment of root zone restriction.
文摘Lalo Classic Opera The King Duration:April 3rd-April 6th,2008 Avenue:National Grand Theater-Opera House Ticket Price:R MB 180/380/580/880/1080/1380 Performer:Theatre National de Toulouse of France Composer:Edouard Lalo(French) Conductor:Michel Plasson(French) Edouard Lalo composed for a wide variety of forms, including stage,symphony orchestra,and chamber music. Unfortunately,his stature outside his homeland rests almost entirely on one spectacular violin showpiece,the Symphonie Espagnole.Within France,however,he is noted for his other works as well,including a single operatic masterpiece'Le Roi D'Ys'(the King of the legendary city of Ys).Lalo himself considered this work to be his greatest work.
文摘Burkitt＇s lymphoma is a highly aggressive non-Hodgkin lymphoma, often presenting in extra-nodal sites. It generally has a poor spontaneous outcome and needs aggressive treatment with systemic and intrathecal chemotherapy. Occurrence at the gastric site is rare. We report the case of a 39-year old woman who presented with a prominent ulcerated lesion of the antrum corresponding histologically to a Burkitt＇s lymphoma associated with He/icobacter py/ori （H pylori） infection. Interphase fluorescence in situ hybridization （FISH） demonstrated c-MYC gene rearrangement in tumour cells without BCL2 or BCL6 gene translocations. Ulcer healing and tumour regression with a complete histological response were obtained 8 wk after Hpylori eradication. In spite of this complete remission, taking into account the high risk of recurrence, the patient received systemic and intrathecal chemotherapy. Two years later, the patient remained in complete remission. This is the first report of a gastric Burkitt＇s lymphoma responding to Hpylori eradication. These findings raise the question of the potential role of H pylori in the pathogenesis of some gastric Burkitt＇s lymphomas, and show the importance of searching for and eradicating the bacteria in combination with conventional chemotherapy regimens.
文摘Thirty bloomed hybrids of C. azalea were selected to have been studied. Of them, 10 cross-combinations were included. The results showed that the hybrids were consistently tended to C. azalea on flower bud formation and development, blooming period, leaf trait and plant growth, but flower color, flower form and flower size of the hybrids, in a great degree, were dependent on the traits of another non-C, azalea＇s cross-parent. The hybrids all can bloom from summer to December and even to next spring. The hybrids＇ photographs illustrated in the paper show that their flowers are beautiful with different color, form and size. Also some of genetic laws of C. azalea＇s hybrids were discussed. These fire-new hybrids firstly fill the blank that no camellia flowers can be enjoyed in summer in the world.
基金supported by the National Key Research and Development Program of China(2017YFA0206801)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB20000000 and XDB10040304)the National Natural Science Foundation of China(No.21373201and No.21433014)
文摘Dynamics of ammonium and ammonia in solutions is closely related to the metabolism of arnrnoniac compounds, therefore plays an important role in various biological processes. NMR measurements indicated that the reorientation dynamics of NH4＋ is faster in its aqueous solution than in rnethanol, which deviates from the Stokes-Einstein-Debye rule since water has higher viscosity than methanol. To address this intriguing issue, we herein study the reorientation dynamics of ammonium ion in both solutions using numerical simulation and an extended cyclic Markov chain model. An evident decoupling between translation and ro- tation of methanol is observed in simulation, which results in the deviation of reorientation from the Stokes-Einstein-Debye rule. Slower hydrogen bond （HB） switchings of ammonium with rnethanol comparing to that with water, due to the steric effect of the rnethyl group, remarkably retards the jump rotation of ammonium. The observations herein provide useful insights into the dynamic behavior of ammonium in the heterogeneous environments including the protein surface or protein channels.
文摘The role of mycorrhizal symbiosis in the alleviation of salinity stress induced by sodium chloride （NaCI） was investigated. Three artichoke hybrids, Madrigal F1, Opal FI, and Concerto FI （Nunhems company）, were grown in pot in controlled environment with two different mycorrhizal treatments （with or without Glomus viscosum）. Two months after inoculation, the fungus established well on roots of the Madrigal and Opal plants with higher colonization and dependency values, instead the Concerto plants showed lower mycorrhizal dependency and colonization rate. Mycorrhizal symbiosis generally improved plant vegetative growth and sustained plant physiology increasing stomatal conductance and SPAD values. The root systems of two months old artichoke plantlets, both inoculated and non inoculated, were placed in distilled water enriched with different salt concentrations （0, 100, 150, 200, 250 mM NaCI） to study the wilting response. A visual rating system was developed defining various wilting indexes （TO, no wilting; T1, foliar damage on less than 50% of vegetal tissues of basal leaves; T2, initial wilting and foliar damage on more than 50% of vegetal tissues of basal leaves; T3, foliar damage on the apical leaves; and T4, total wilting）. Mycorrhizal plants reached later the wilting indexes than non-mycorrhizal plants. Electrolyte leakage by leaves after salinity imposition was higher in non-mycorrhizal plants and the vegetal tissues were severely damaged especially in the basal leaves. The greater tolerance observed in the mycorrhizal plants could be in agreement with the improvement in growth stimulated by mycorrhizal symbiosis, which leads to the dilution of toxic ions.
文摘In this paper, vector autoregressive （VAR） models have been recognized for the selected indicators of Dhaka stock exchange （DSE）. Bangladesh uses the micro economic variables, such as stock trade, invested stock capital, stock volume, current market value, and DSE general indexes which have the direct impact on DSE prices. The data were collected for the period from June 2004 to July 2013 as the basis on daily scale. But to get the maximum explorative information and reduction of volatility, the data have been transformed to the monthly scale. The outliers and extreme values of the study variables are detected through box and whisker plot. To detect the unit root property of the study variables, various unit root tests have been applied. The forecast performance of the different VAR models is compared to have the minimum residual. Moreover, the dynamics of this financial market is analyzed through Granger causality and impulse response analysis.
文摘Concession contracts in highways often include some kind of clauses （for example, a minimum traffic guarantee） that allow for better management of the business risks. The value of these clauses may be important and should be added to the total value of the concession. However, in these cases, traditional valuation techniques, like the NPV （net present value） of the project, are insufficient. An alternative methodology for the valuation of highway concession is one based on the real options approach. This methodology is generally built on the assumption of the evolution of traffic volume as a GBM （geometric Brownian motion）, which is the hypothesis analyzed in this paper. First, a description of the methodology used for the analysis of the existence of unit roots （i.e., the hypothesis of non-stationarity） is provided. The Dickey-Fuller approach has been used, which is the most common test for this kind of analysis. Then this methodology is applied to perform a statistical analysis of traffic series in Spanish toll highways. For this purpose, data on the AADT （annual average daily traffic） on a set of highways have been used. The period of analysis is around thirty years in most cases. The main outcome of the research is that the hypothesis that traffic volume follows a GBM process in Spanish toll highways cannot be rejected. This result is robust, and therefore it can be used as a starting point for the application of the real options theory to assess toll highway concessions.
文摘In the city of La Plata （Argentina） and the surroundings, there are tomato landraces, widely known as ＂tomate platense＂ and particularly prized because of their flavor. The objective was to evaluate seven promissory lines of ＂tomate platense＂ （TL） derived from local varieties and a commercial hybrid （CH） considering yield, fruit characters and their possible associations. Nine plants per treatment were arranged in a randomized complete block design （r = 4）. The following parameters were determined： diameter （cm）, height （cm）, diameter/height （D/H） ratio, weight per fruit （g）, number of locules, the average number of fruits per plant, the average weight of fruits per plant （kg/ptant）, the yield （ton/ha） and the survival percentage. ANOVA, Tukey＇s test and Pearson correlation coefficient were applied. The TL showed greater （P ≤ 0.01） diameter, D/H ratio and number of locules than CH. In all materials, both diameter and height were associated （P ≤ 0.05） with the weight per fruit. Six of TL had greater （P ≤ 0.01） weight per fruit than HC. Respect to number of fruits per plant, weight of fruits per plant and yield, there were no significant differences among the materials. The survival for CH was lower （P ≤0.05） than that for TL. Although fruits with a smaller size and less flattened have been selected, the lines show enough similarity in these characters that identified their common origin. With the fruits smaller and more uniform, and having no joined fruits, these lines may be of interest to be cultivated under low-input system conditions and practical for low-income producers.
文摘This paper aims to examine the existence of calendar anomalies including month-of-year effect, turn-of-month effect, and weekend effect in Thai stock market. The stock return is computed from SET index during 1988 to 2009 and the SET50 index gathered since it was created in 1995. The unit root test is performed to ensure that the stock return series have no unit root. The multiple regression techniques using dummy variables are employed to test the difference of the return during each calendar anomalies period. If the regression model suffers from conditional heteroskedasticity, the GARCH （1, 1） model will be used instead of normal ordinary least square regression. It was found that the calendar anomalies exist in Thai stock market. The return is abnormally high during December and January, which can be addressed to be the turn-of-year effect. The return during the turn-of-month period, which can be defined as the last trading day and the first four trading days of the following months, is also abnormally high. Finally, the return is also abnormally high on Fridays but abnormally low on Mondays, which is addressed as weekend effect. This may create the opportunity to make above-average profit to investors exploiting these calendar anomalies. Although these calendar anomalies may be difficult to be exploited in practice because of transaction costs and ability to replicate the stock index, the existing evidence of calendar anomalies can help investors as the clue for the timing of investment.
基金Project supported by the National Natural Science Foundation of China （Nos. 61100105, 61572020, and 61472332）, the Natural Science Foundation of Fujian Province of China （No. 2015J01273）, and the Fundamental Research Funds for the Central Universities, China （Nos. 20720150002 and 20720140520）
文摘In this paper, we present a novel geometric method for efficiently and robustly computing intersections between a ray and a triangular Bezier patch defined over a triangular domain, called the hybrid clipping （HC） algorithm. If the ray pierces the patch only once, we locate the parametric value of the intersection to a smaller triangular domain, which is determined by pairs of lines and quadratic curves, by using a multi-degree reduction method. The triangular domain is iteratively clipped into a smaller one by combining a subdivision method, until the domain size reaches a prespecified threshold. When the ray intersects the patch more than once, Descartes＇ rule of signs and a split step are required to isolate the intersection points. The algorithm can be proven to clip the triangular domain with a cubic convergence rate after an appropriate preprocessing procedure. The proposed algorithm has many attractive properties, such as the absence of an initial guess and insensitivity to small changes in coefficients of the original problem. Experiments have been conducted to illustrate the efficacy of our method in solving ray-triangular Bezier patch intersection problems.
