Carbon fluxes and their response to environmental variables in a Dahurian larch forest ecosystem in northeast China

The Dahurian larch forest in northeast China is important due to its vastness and location within a transitional zone from boreal to temperate and at the southern distribution edge of the vast Siberian larch forest. The continuous carbon fluxes were measured from May 2004 to April 2005 in the Dahurian larch forest in Northeast China using an eddy covariance method. The results showed that the ecosystem released carbon in the dormant season from mid-October 2004 to April 2005, while it assimilated CO2 from the atmosphere in the growing season from May to September 2004. The net carbon sequestration reached its peak of 112 g.m^-2.month ^-1 in June 2004 （simplified expression of g （carbon）.m^-2.month^-1） and then gradually decreased. Annually, the larch forest was a carbon sink that sequestered carbon of 146 g-m^-2.a^-1 （simplified expression of g （carbon）.m^-2.a^-1） during the measurements. The photosynthetic process of the larch forest ecosystem was largely affected by the vapor pressure deficit （VPD） and temperature. Under humid conditions （VPD 〈 1.0 kPa）, the gross ecosystem production （GEP） increased with increasing temperature. But the net ecosystem production （NEP） showed almost no change with increasing temperature because the increment of GEP was counterbalanced by that of the ecosystem respiration. Under a dry environment （VPD 〉 1.0 kPa）, the GEP decreased with the increasing VPD at a rate of 3.0 μmol.m^-2.s^-1kPa -1 and the ecosystem respiration was also enhanced simultaneously due to the increase of air temperature, which was linearly correlated with the VPD. As a result, the net ecosystem carbon sequestration rapidly decreased with the increasing VPD at a rate of 5.2 μmol.m^-2.s-1.kPa^-1. Under humid conditions （VPD 〈 1.0 kPa）, both the GEP and NEP were obviously restricted by the low air temperature but were insensitive to the high temperature because the observed high temperature value comes within the category of the optimum range.

松声入耳心愈宁——从《万壑松风》看康熙和乾隆的志趣

偃盖龙鳞万壑青, 逶迤芳甸杂云汀。 《白华》朱萼勉人事, 爱敬《南陔》乐正经。 这是康熙为避暑山庄“万壑松风”所写的定景诗。“万壑松风”是山庄康熙三十六景的第六景,建于1708年（康熙四十七年）。此景据冈背湖,前临万壑,因“长松环翠,壑虚风度”而得名。这里的环境幽静而秀美:西北山峦起伏,万木葱笼;东北湖光荡漾’菱荷芬芳。清代皇帝来山庄避暑时,常在此处读书和批阅奏章。

瞻仰黄花岗七十二烈士墓

外一首 清明时节,瞻仰黄花岗七十二烈士墓,心潮澎湃。看江山多娇、形势大好,缅怀先烈,感慨以系之。

Chemical Components from the Fungus Engleromyces goetzei

A new ceramide, (2S,3S,4R, 10E)-2-[(2'R)-2'-hydroxytetracosanoyl amino]-10-octadecene-1, 3,4-triol (1), together with twelve known compounds, cerebroside A, cerebroside B, cerebroside D, cytochalasin D, epoxycytochalasin D, cytochalasin C, loganin, cerevisterol, ergosta-7,22-dien-3beta, 5alpha, 6alpha-triol, ergosta-4,6,8(14),22-tetraen-3-one, ergosterol peroxide and ergosta-5,7,22-trien-3-ol, was isolated from ethyl acetate fraction of Engleromyces goetzei P. Henn. The structure of new ceramide (1) was elucidated by spectral data and chemical method, especially by 2D-NMR techniques. All of the compounds except cytochalasin D were first obtained from this fungus.

CATASTROPHIC ECO-ENVIRONMENTAL CHANGE IN THE SONGNEN PLAIN,NORTHEASTERN CHINA SINCE 1900S

Although the Songnen Plain in the northeastern China was developed relatively late in the temperate zone of the world, its eco-environment has changed greatly. This paper analyzes the changes of land cover and the rates and trends ofdesertification during the past 100 years in the Songnen Plain. According to the macroscopic analysis, we find that the eco-environment in the plain has reached to the threshold of catastrophic change since the 1950s. The Thom Needle Catastrophic Model was used to determine and validate this conclusion. Human activities, including large-scale construction projects, such as huge dams and dikes, and excessive grazing were the primary factors contributing to regional eco-environmental catastrophe. And irrational reclamation of the wilderness also affected the eco-environmental change. The results reveal the complex human-land interactions.

Land Use/Cover Changes and Environmental Consequences in Songnen Plain,Northeast China

The Songnen Plain in Northeast China,one of the key national bases of agricultural production,went through remarkable land use/cover changes in recent years.This study aimed to explore the long-term land use/cover changes and the effects of these changes on the environment.The Landsat-based analysis showed that,during 1986-2000,cropland,built-up land and barren land had increased,among which cropland had the largest increase of 9,198km2 with an increase rate of 7.5%.Woodland,grassland,water body and swampland had decreased correspondingly,among which grassland had the most dramatic decrease of 6,127km2 with a decrease rate of 25.6%.The transition matrix results revealed that grassland,woodland and swampland were the three main land use types converted to cropland.Climate warming created the potential environment for the conversion of grassland and swampland into cropland.Land resources policy made by central and provincial governments of China affected the pattern and intensity of land use.Land use/cover changes accompanied by climatic variation brought out a series of environmental consequences,such as sand desertification of land,land salinization and alkalinization,grassland degradation,and more frequent floods.Under this circumstance,optimized land use structure and restoration measures are needed.

Research on the relationship between financial slack and R ＆ D investment in manufacturing industry under dynamic environment

As a part of the redundancy of organization, financial slack has become the focus of academic research. This paper takes the listed companies of manufacturing industry above Designated Size as sample, using multiple regressionto examine the relationship between corporate financial slack and R ＆ D investment under dynamic environment, using the Malmquist index method based on DEA model to analyze the innovation efficiency of Chinese manufacturing industry during the period of 2009-2013. The results show that： Financial slack and R ＆ D investment intensity presents inverted ＂U＂ type relationship in？sample？companies, and the relationship is positively regulated by environmental dynamism; Financial slackpromotes R ＆ D investment but have lag effect.

Distribution of Methyl Mercury in Rana chensinensis and Environmental Media in Gold-mining Areas of Upper Reaches of Songhua River,China

The distribution characteristics of methyl mercury in Rana chensinensis and water,sediment and soil in gold-mining areas of the upper reaches of the Songhua River,China were studied by field sampling and laboratory testing.The results show that the methyl mercury contents in water,sediment and soil in gold-mining areas are much higher than those in the control site,indicating that gold-mining activities intensify the methyl mercury pollution in the study area.Methyl mercury contents are in a descending order of sediment > soil > water in the environment,and in a descending order of brain > viscera > muscle > skin in Rana chensinensis.There are significant correlation between methyl mercury contents in Rana chensinensis and those in water and sediment.In particular,the methyl mercury content in the skin of Rana chensinensis is positively correlated with those in water and sediment in spring.Therefore,skin is one of main intake pathways for methyl mercury due to its high permeability.

Introduction of Pinus radiata for afforestation:a review with reference to Aba, China

Pinus radiata D. Don, native to a Californian coastal environment, has been introduced to many parts of the world as an exotic species for afforestation. It is now a major plantation species in the Southern Hemisphere. In 1990, it was introduced to the heavily degraded, dry Min river valley area in Aba prefecture of Sichuan Province, P. R. China. Survival and growth of young trees planted at several sites appear to be reasonable. This review is to serve as an introduction to the large body of literature on P. radiata for forest scientists in China. It covers the following aspects: P. radiata in its native environment and in ex situ plantations, provenance and genetic variations, environmental limitations and climate niche, diseases and pests, lessons from unsuccessful introductions, and the use of P. radiata for ecological restoration. The early growth of P. radiata planted in the dry river valley area is briefly described. Potential problems associated with the introduction of P. radiata in Aba and future research needs are also identified.

Effects of Environmental Factors on Tree Seedling Regeneration in a Pine-oak Mixed Forest in the Qinling Mountains, China

Natural seedling regeneration and tree establishment are affected by various environmental factors. In this study, we established eight, eight, six, and four independent forest stands （each stand was further divided into five subplots） respectively based on the altitudinal gradient, stand density, slope location, and slope aspect to investigate the effects of environmental factors on tree seedling regeneration in a pine-oak mixed forest. The results indicated that the seedling density was significantly higher at altitudes of 1,283 m to 1,665 m, whereas the sapling density did not differ with altitudes. The seedling and sapling density decreased significantly at 1,835 m. The seedling densities on the upper slopes were much higher than those on the middle and lower slopes, whereas the sapling density had no difference. The sapling density decreased southwest （20°-75°） whereas gradually from the it increased on the shady slopes to the northeast （40°）. The seedling density increased from southwest （20°） to northeast （40°The seedling and sapling densities increased with the stand density （850 trees ha-1 to 1,525 trees ha-1） whereas the sapling density was significantly lower in stands （1,9oo trees ha-O. Principal components analysis showed that the slope aspect and stand density had more important roles in tree regeneration in this study region compared with the other two factors. Therefore, our findings suggest that it will be beneficial to keep stands at a moderate density on shady slopes. Appropriate thinning of higher density stands is also expected to promote the natural regeneration of pine-oak mixed forest.

Construction of Pure Mendelsohn Triple Systems

This paper determined the existence of λ-fold pure Mendelsohn triple system of order v satisfying λv(v-1)≡0 (mod 3) and v≥4λ+5, or v=2λ+2, and in the case of λ=4,5,6,which completely settled their existence.

QUANTITATIVE STUDY OF SOIL EROSION AND ELEMENT RUN-OFF IN THE SONGHUA LAKE VALLEY

Under the condition of different precipitation intensities, different gradients, different land-use types and different vegetation coverage, the soil erosion and transference of element (or pollutant) are studied by simulating and analyzing the surface run-off of experimental plots in the catchment area of Songhua Lake, with an area of about 43 370.8km2. And the influencing factors that produce the spatial difference are analyzed and assessed. It is put forward that the irrational land utilization is the reason of soil erosion and pollutant run-off. The gradient of farmland, the growing season of vegetation and the vegetation coverage are chiefly restricting factors that lead to the soil erosion and pollutant run-off. This study can provide the fundamental data for comprehensive planning and harnessing of the non-point source pollution in the valley.

Generalized Toda Mechanics Associated with Loop Algebra L（Br）

A class of generalization of Toda mechanics with long range interactions isconstructed in this paper. These systems are associated with the loop algebras L(B_r) in the sensethat their Lax matrices can be realized in terms of the c = 0 representations of the affine Liealgebras B_r~((1)) . We adopt a pair of ordered integers (m, n) to describe the Toda mechanicssystem when we present the equations of motion and the Hamiltonian structure. We also extract theclassical r matrix which satisfy the classical Yang-Baxter relation. Such generalizations willbecome systems with noncommutative variables in the quantum case.

Analysis of Efficacy of DICE(Dexamethasone,Ifosfamide,Cisplatin and Etoposide)Regimen on Recurrent and Refractory Intermediate and High Grade Non-Hodgkin's Lymphoma

OBJECTIVE Thus far there is no standard salvage regimenfor patients with recurrent and refractory intermediate and highgrade non-Hodgkin's lymphoma (NHL). This study intends toinvestigate the therapeutic efficacy of the DICE (dexamethasone,isofosfamide, cisplatin and etoposide) regimen on the recurrentand refractory NHL, and to observe the related adverse effects.METHODS Clinical records of 22 patients with recurrent andrefractory NHL, who failed to achieve a remission from theCHOP [cyclophosphamide, hydroxydaunomycin/doxorubicin(adriamycin), oncovin, prednisone] regimen within 2 to 6 cyclesof treatment, were reviewed. DICE, as a salvage regimen with amedian course of treatment of 4 cycles (ranging from 2 to 7 cycles),was now used, and evaluation of the therapeutic efficacy andadverse effect of DICE was conducted in all the patients. Of the 22NHL cases, 8 were of T-cell origin and the other 14 B-cell origin.Salvage treatment was performed in the patients, with appraisal,prevention and treatment of the toxic reactions.RESULTS Following DICE treatment in the 22 patients, thetotal effective rate of the regimen was 63.6%, and the completeremission (CR) rate was 40.9%. The effective rates of DICE onthe T and B-cell sourced NHL were 75.0% and 57.1%, and the CRrate were 37.5%, 42.9%, respectively (P >0.05). An increase of thelactate dehydrogenase (LDH) level accompanied by a giant lumpwas the short-term effect on patients with recurrence (mean P <0.05) who were drug resistant. Myelosuppression, digestive systemreaction and alopecia were the commonly-seen complications inthe patients who received DICE regimen. All patients recoveredafter treatment, and no chemotherapy-related death occurred.CONCLUSION DICE regimen is effective in treating refractoryand recurrent NHL.

Constitutive Model of Saturated Soft Clay with Cyclic Loads under Unconsolidated Undrained Condition

An equivalent visco-elastic model of saturated soft clay was studied under unconsolidated undrained (UU) condition, which can be used to evaluate the stability of ocean foundation. Cyclic triaxial compression and extension tests were conducted to study the parameters of the model. Results showed that the relationships of the damping ratio and the octahedral shear modulus with the octahedral cyclic shear strain were nearly unique, when the initial octahedral shear stress ratios of specimens were equal to 0.3, 0.5 and 0.7. The relationships of the damping ratio and the octahedral shear modulus with the octahedral cyclic shear strain determined from the cyclic triaxial compression tests were basically the same as those determined from the cyclic triaxial extension tests. Furthermore, the relationships were not related to the initial stress condition, the test stress state and the octahedral cyclic shear stress ratio. The relationships determined from the cyclic triaxial tests under no deviatoric stress were basically the same as those determined from the cyclic triaxial tests under deviatoric stress. The change of the octahedral cyclic accumulative strain with the number of cycles was unique under different tests stress states. An equivalent visco-elastic constitutive model of saturated soft clay under UU condition was initially established.

Biomass growth characteristics of 13-year-old Pinus densiflora S.et Z.in a post-fire plantation on different contour conditions in Samcheuk,Korea

We used preliminary data to estimate the growth volume of artificially reforested Pinus densiflora in a post-fire area on three different contour conditions. We compared the growth of P. densiflora on a south-facing slope(Ssth), north-facing slope(Snth) and ridge area(Ridge), using 7 trees selected from each stand aspect. The tree height, diameter and growth volume were measured and the dry weight of each plant part were compared and analyzed. The results revealed that the total dry weight was highest on Ssth(5992.3 g), followed by Snth(4833.2 g) and lowest on Ridge(3160.1 g). The height growth was highest on Snth(285.8 cm), followed by Ssth(274.5 cm) and lowest on Ridge(211.5 cm). The diameter growth was greatest on Ssth(7.37 cm), followed by Snth(7.10 cm) and lowest on Ridge(5.72 cm). The volume growth was highest on Ssth(4257.7 cm3), followed by Snth(3750.7 cm3) and lowest on Ridge(2093.7 cm3). Therefore, we should consider and include the concept of slope orientation together with differences in habitat environments in afforestation projects when creating artificial forests with P. densiflora. These study results can serve as important preliminary data for future establishment of artificial forest of P. densiflora in a post-fire plantation.

Zooplankton community structure in relation to environmental factors and ecological assessment of water quality in the Harbin Section of the Songhua River

To study the relationship between zooplankton community structure and environmental factors and water quality in the Harbin Section of the Songhua River,investigations were carried out in June,August,and October 2011.Canonical correspondence analysis(CCA) and saprobic indices were used to process and analyze the data.Seasonal variability was identified as a significant source of variation,which explains the fluctuation in zooplankton density.In autumn,the dry season,water residence time increased and zooplankton biomass and abundance accumulated in the slow flowing waters.Zooplankton abundance increased when food conditions improved.Therefore,the total zooplankton abundance in autumn is much higher than that in spring and summer.According to the saprobic indices,all the sample sites had mesosaprobic water and water quality was worse in autumn.CCA revealed that temperature accounted for most of the spatial variation in the zooplankton community.Moreover,pH,dissolved oxygen saturation,and turbidity were important factors affecting zooplankton community distribution.