Supported by Key Scientific Research Project of Tibet Autonomous Region; Tibet Graduate Student Innovation Program (YJS2017-14).

△These authors contribute equally to the paper.

1 Introduction

Euonymussanguineus is a small tree or shrub in the Celastraceae family[1], which is endemic to China. E. sanguineus is distributed in Tibet, Yunnan, Sichuan, Gansu, Shaanxi, Henan, Hubei. In Tibet, E. sanguineus grows in the edge of fir forest and thickets at an altitude of 2 400-3 500 m. It is produced in Jilong, Dingri, Yadong, Motuo, Bomi and Milin, most concentrated in Milin. The branch and leaf structure of E. sanguineus is clear, the shape is graceful, and the flower shape is unique. The fruit is small and it is brightly colored, like a pink pendant. In particular, the fruit is like a flower after ripening and cracking, and after autumn, the leaves turn bright crimson, like a graceful girl in red. At the same time, the flower, fruit and leaf of E. sanguineus have a long period, with a very high ornamental value. The E. sanguineus has strong adaptability to the land conditions, and can purify the air, with very strong resistance. It has the obvious improvement soil and the ecological environment benefit. The widespread planting of E. sanguineus can play an important role in the ecological protection and restoration in Tibet, and can enrich the ecological diversity. The root and bark of the genus Euonymus contain many kinds of medicinal components, which have great medicinal and health value[2]. Its root and bark contain a variety of insecticidal active ingredients, hard rubber resources[2-5], and seeds have high oil content, up to 30%-50%. It can be used not only as edible oil, but also as non-grain diesel energy resources[6-7]. It has great development potential in agriculture, daily chemicals, food and industry, all of which make the study of E. sanguineus have important significance.

At present, there is no report on the study of E. sanguineus, the population of E. sanguineus is small, most of them are adult plants, the number of young plants is very small. The mortality of seedlings is very high, so it belongs to the declining population. Therefore, the investigation of its habitat conditions and the analysis of the causes of its population decline can lay a foundation for the selection of the optimal habitat conditions and its species protection, introduction, breeding, cultivation, resource development and garden application.

2 Morphological characteristics ofE. sanguineus

E. sanguineus is generally 2-7 m tall, the young branch is grayish brown or purple brown. The leaf texture is flexible and thin, elliptic, ovate-elliptic or ovate, 4-9 cm long and 2-4.5 cm wide. The leaf apex is acuminate, and the leaf margin is finely serrate; the petiole is 5-10 mm long; cymes axillary, total pedicel of 1.5-6 cm long; white or white green flowers, tetramerous; flower disc square; stamens glabrous. Flowering period is May-July, seed-setting period is August-October, and the capsule is oblate, pink, about 1 cm in diameter, 4-winged, triangular wings. In the mature stage (September to October), the seeds dehisce and can be counted as red seeds, and the fruits are usually 4-loculed and one seed per locule[1].

3 Overview of the study area

The study area is located along the Yarlung Tsangpo River in Milin County, Nyingchi City, Tibet Autonomous Region, with geographical coordinates of 93°49′-93°56′ E，29°6′-29°10′ N. Milin County is the plateau temperate and semi-humid monsoon climate area, and because the warm current from Indian Ocean and the Bay of Bengal passes through the Yarlung Tsangpo River passage, this area forms a special climate of subtropical, temperate and cold zone. The basic climatic conditions of the study area are shown in Table 1[8].

Table 1 Main climatic parameters of the investigation area ofEuonymussanguineus in Tibet

RegionAnnualsunshinehours∥hAnnualSunshine%Annualaveragetemperature℃Monthlyaveragetemperature℃Averagedailytemperaturerange∥℃Monthlyaveragemaximumtemperature℃Monthlyaverageminimumtemperature℃≥0℃cumulativetemperature℃≥10℃cumulativetemperature℃DurationdMilin1718．9398．2-5．211．815．43．430302180154RegionExtrememaximumairtemperature℃Extrememaximumgeotemperature℃Extrememinimumairtemperature℃Extrememinimumgeotemperature℃AnnualprecipitationmmAnnualevaporationmmAnnualwaterdeficiencymmFrost⁃freeperioddFirstfrostmm/ddLastfrostmm/ddMilin28．869．3-15．8-16．1675．11185．94615410/145/16

4 Research methods

5.3 Experiment on the key factors in seedling lethality According to the phenomenon of low survival rate of seedlings found in the investigation, it was suggested that the light, soil and litter might be the key factors of death, except the bad habitat conditions such as large temperature difference, low precipitation and human and animal disturbance. Therefore, the key factors of seedling lethality were studied.

POD数据后处理应用程序包由数据输入模块、POD数据处理核心模块和数据输出模块等3个功能模块组成(见图1)。

4.2 Seedling survival statistics The number and distribution range of E. sanguineus seedlings, and the number of seedlings after four months were measured in the sample plots, and the survival amount of seedlings was calculated.

The collected leaves were washed, naturally dried, ground and sifted, and accurately weighed to be 1 g (dry weight), and treated with 50 mL of distilled water for 30 min of ultrasonic processing. After 48 h of extraction, it was centrifuged to obtain the supernatant, namely the original solution of extract. After it was mixed with distilled water, it was divided into four concentration gradients: 100%, 75%, 50%, 25%, with clear water as the control. The seedlings were cultured in solution and their condition was observed. As can be seen from Table 10, the seedlings died when they were put into the extract. The survival time of the seedlings increased with the decrease of concentration, while the seedlings of the control group were normal. Thus, it was found that the substances in the leaves caused the death of the seedlings. The results indicated that the leaves of E. sanguineus had autotoxic effect, which matched with the fact the seedlings of E. sanguineus could not survive under the plant. There were scarce under-forest and surrounding shrubs and herbs, and the simple structure also confirmed that the leaf of the E. sanguineus had autotoxicity.

4.3 Seed-setting ability investigation Using sample plot statistical method, the E. sanguineus plants were selected in each sample plot, camera was used to photograph the sunward surface and the shady surface of the flowering and seed-setting plants, and according to the differences of flower, fruit and leaf color and area, the rate of flowering and seed-setting was estimated. A total of 100 E. sanguineus fruits were selected randomly in each sample plot. After the capsule dehisced completely, the number of seeds was counted (for the seeds falling off, the residual locules in capsule can be counted). The seed yield, the number of empty seeds, the number of rotted seeds and the number of full seeds were counted, and the abortive rate, the disease rate, the rate of insect pests and the rate of plumpness were calculated.

4.4 Experiment on the key factors in seedling lethality The pH of soil was measured by digging three soil samples from the sample plot. The seedlings were cultivated under different soil and different light intensity and the growth of seedlings was observed. The litters of E. sanguineus were collected, and the influence of litters of E. sanguineus on the seedling growth was observed by allelopathic experiment.

5 Results and analysis

A tentative experiment of GRAPES En-3DVAR hybrid data assimilation method over the Tibet Plateau

5.3.1 Light. Light is an important environmental factor affecting seed germination and seedling growth and survival[19]. 50 seedlings of the same growth trend were taken from four investigation sites and planted in the original soil, and were treated with four kinds of light intensity. four groups of 10 plants, a total of 50 seedlings, were taken for a light intensity treatment. The seedlings of four groups were observed for three months. Table 8 showed that the seedlings of E. sanguineus grew well under 1/3-1/2 light intensity, followed by the growth status under full light intensity, and grew slowly under 1/5-1/4 light intensity, but no seedlings died. The measurement of light intensity under adult plants in four investigation sites showed that the light intensity was in the range of 3/10-4/5, but the seedlings died a lot. Because of the sharp contrast between the two, the light was not the key factor of seedling death.

5.1.1 Main climatic parameters in the investigation area. From the main climatic parameters of E. sanguineus habitat investigation area in Table 1, it was found that E. sanguineus growth area is located in the Yarlung Tsangpo River valley area, where the temperature difference between day and night is big, the precipitation is little, the evaporation is big, and the climate is dry and hot. It is featured by the dry and hot river valley climate conditions. The data showed that the growth condition was very bad, which was very bad for seed germination and seedling survival.

5.3.2 Soil. Soil acidity and alkalinity affect the chemical reaction, microbial activity and the availability of nutrients in the soil, thus affecting the physical and chemical properties of the soil and the growth of crops. The pH range of soil adapted to growth by different plants is different[20]. The soil used for "seedling growth under different light intensity" was native soil, and no seedlings died. Soil acidity and alkalinity testing results showed that the pH of the soil was in the range of 7.2-9.4, it was alkaline, and the seedlings were later planted in the acid soil. Table 9 showed that the seedlings of E. sanguineus could also grow in acid soil, and grew well in weak acid soil, but no seedlings died. Taken together, soil was not a key factor in seedling death.

Table 2 Basic information of community habitats

CommunityCoordinatesElevation∥mSlope∥°AspectSoiltypeSoilthickness∥mDisturbancedegree193°56′0．58＂E，29°10′40．75＂N303615NorthwestMountainbrownsoil0．8Light293°54′46．10＂E，29°9′32．33＂N2973<3-Mountaincinnamonsoil0．6Moderate393°54′26．39＂E，29°9′32．33＂N299120NortheastMountaincinnamonsoil0．6Moderate493°49′51．59＂E，29°7′9．99＂N302025NortheastMountainbrownsoil0．9Light

5.1.2 Associated and competitive species. As shown in Table 3, according to the investigation, the trees are competitive species, shrubs are competitive and associated species, and grasses and ferns are associated species in the habitat. There was a remarkable feature in all the sites investigated, that is, the plant species began to be rich except for a small number of herbs and ferns in the crown range (with no other plants at all).

2.1.4模式优点该治理模式适宜治理发展型侵蚀沟，实施后控制侵蚀沟效果好、见效快，工程措施实施后的当年即可实现稳固沟头，拦截泥沙的作用；对植物措施的依赖较少，占用耕地少。

From the tables and figures in the article, it was found that with the decrease of associated and competitive species, and the decrease of disturbance by human and animal, the basic characteristic index of the population of E. sanguineus increased and developed in a favorable direction. This was related to the improvement and upgrading of the growing environment, as well as the acquired growth resources and space, as a result of the decrease of associated and competitive species. However, the decrease of associated and competitive species, especially the decrease of shrubs, weakened its protection circle and it was easily disturbed by human and animal activities. It is difficult for seeds to germinate, seedlings to survive, and the characters of plant are weak due to the compaction of soil under or near the plant which is seriously disturbed by human and livestock, causing a great impact on the growth and development of the population.

However, during the investigation in many places, due to human and animal disturbance and natural factors, it was found that the natural habitat of E. sanguineus presented many separate small fragments, that is, habitat fragmentation. Habitat fragmentation can reduce the total area of the original habitat and produce isolated heterogeneous populations, thus affecting interspecific gene exchange, population viability, species interactions and a series of ecological processes[9-11], which is a main cause of biodiversity decline and species endangerment and extinction[12-13]. Therefore, habitat fragmentation is very detrimental to the population development of E. sanguineus.

Table 3 The main components of associated and competitive species

CommunityTreesShrubsHerbsFerns1AbiesgeorgeiOrrvar．smithii，Pinusdensata，QuercusaquifolioidesRibesorientale，Spiraeabella，Rosasikan⁃gensisFragarianubicolaDryopterisnyingchiensis，Drynariadelavayi2Quercusaquifolioides，Hippophaerh⁃amnoidesRhamnusvirgata，Piptanthusconcolor，Co⁃toneastermicrophyllusDuchesneaindicaDrynariadelavayi3Cupressusgigantea，Quercusaquifo⁃lioides，HippophaerhamnoidesPiptanthusconcolor，Hippophaerham⁃noides，CaraganasinicaPedicularisdavidii，Hemi⁃phragmaheterophyllumDrynariadelavayi4NoneSorbusrehderiana，Berberisamurensis，Ca⁃raganasinicaNoneDrynariadelavayi

5.2 Analysis of population structure

5.2.1 Analysis of plant population characteristics. By comparing the data of each sub-item in Table 4 and Fig.1, it was found that the population density had a positive correlation with DBH, crown width, leaf length and branch length, but a negative correlation with tree height. The growth of plant population showed a horizontal development trend. It was found that the population density of E. sanguineus was very small, showing broken point distribution, and the population growth was slow, suggesting that its growth was a long-term accumulation process. The adult plants dominate the population and there are very few young plants, which makes the basic data about the population of E. sanguineus at a relatively high level. In fact, it reflected that the population of E. sanguineus was small, the spatial structure presented the random distribution, and the age structure presented the aging trend, so that its population structure was not complete and had no continuity.

Table 4 The basic characteristics ofEuonymussanguineus in different communities

CommunityDensityplant/haAverageDBH∥cmAveragetreeheight∥mAveragecrowndiameter∥mAverageleaflength∥cmAveragecurrentbranchlength∥mAveragebiennialbranchlength∥m1417．94．743．42×3．165．240．420．512315．64．463．84×3．615．060．340．473619．44．374．33×4．016．880．490．594820．23．894．68×4．267．670．530．62

5.2.2 Analysis of seedling survival. As shown in Table 5, it was found that there were current seedlings in and out of the crown diameter of plant, but there were no plants of more than two years in the crown diameter range, and there were few plants of more than two years in the area outside the crown diameter range. The number of young seedlings and adult plants were counted in different radius with the plant as the center from four sample plots. The number of seedlings in all sample plots decreased sharply with the increase of radius, and the number of plants over two years old was very small, and increased first and then decreased sharply with the increase of radius. The seeds of the four communities of E. sanguineus germinated and died one after another, and the number of seedlings more than two years old was also very small, and the survival amount of the seedlings was very small. The investigation also found that the surviving seedlings were in the area with the radius of more than 5 m, that is, it was beyond the crown coverage range (Table 6). The above two tables showed that the mobility of seeds was very weak, and they belonged to the indifferent species; the under-forest regeneration ability was poor, the survival rate of seedlings was very low, and the population was difficult to reproduce and develop.

Fig.1 The correlation between population density and DBH, crown diameter or tree height

Table 5 Survival rate of seedlings in different areas under canopy

CommunityAgeofseedlingsItemRadiusrange∥m0-55-1010-155-201Current⁃yearNumberofseedlings44352312Twoyearsormore44422Current⁃year3226189Twoyearsormore22223Current⁃year70625134Twoyearsormore1111994Current⁃year95877051Twoyearsormore19181513

Table 6 Survival rate of seedlings in different periods

CommunityAgeofseedlingsItemNumberofdays0204060801001201Current⁃yearNumberofseedlings44352312400Twoyearsormore44422212Current⁃year3226189300Twoyearsormore22222223Current⁃year706251342130Twoyearsormore1111999634Current⁃year9587705132111Twoyearsormore191815131386

5.2.3 Seed-setting ability. Seed is an important link in the life cycle of plants, and is the beginning of new life of young plants, related to the future fate of the population. Much attention has been paid to the ecological effects of seed size and quality on the successful settlement and survival of seedlings[14]. When the population of almost all species decreases, the most direct consequence is the increase of inbreeding coefficient and the subsequent inbreeding decline, and the decrease of population fitness[15-17]. The decrease of plant population fitness is reflected in a series of links in plant life cycle. Seed germination is a key link in plant life cycle, which often determines whether the population renewal is successful or not. The study on the germination of endangered plant seeds is helpful to exploring the mechanism of endangered plant seeds and to designing reasonable protective measures for endangered plant seeds[18].

5.1 Comparative analysis of different habitat conditions and their impacts

As can be seen from Fig.2, the average flowering and seed-setting rate of population in sample plot 4 was the highest among the 4 populations, while the number of seedless fruits was the lowest, which indicated that the seed-setting ability was relatively high. The seed-setting rate of all the E. sanguineus populations was very low, the highest seed-setting rate was only 43.0%, the lowest was only 38.6%, and the percentage of seedless fruits was more than 50%, showing a very low seed-setting ability. The statistics of seeds of 100 fruits showed that the percentage of full seeds was also small, the majority of seeds were damaged by insect pests, or rotten seeds and empty seeds, which greatly reduced the base of seed germination (Table 7). On the basis of the above two tables, it was found that the seed bearing ability of E. sanguineus was low, the pest was serious, and the seed fullness rate was very low, which made the seed germination probability greatly reduced, and it was adverse to the development of the population.

Fig.2 Analysis of seed-setting ability ofEuonymussanguineus population in different communities

Table 7 Some basic characteristics of seeds in different communities

CommunitySeedyield(per100fruits)Numberofemptyseeds(abortionrate∥%)Numberofrottedseeds(diseaserate∥%)Numberofpests(pestrate∥%)Numberoffullseeds(fullnessrate∥%)118058(32．2)46(25．6)49(27．2)27(15．0)217261(35．5)44(25．6)27(15．7)40(23．2)319253(27．6)48(25．0)30(15．6)61(31．8)419652(26．5)35(17．9)29(14．8)80(40．8)

4.1 Sample plot setting and investigation On the basis of comprehensive investigation of the region along the Yarlung Tsangpo River in Milin County, the community distribution of E. sanguineus was investigated by means of sample plot investigation method. Four typical vegetation communities were selected in the sample plot, and the basic situation of sample plot was shown in Table 2. Three 100 m×100 m sample plots were set up in each community. The altitude, slope, aspect, soil type, thickness and disturbance degree of human and animal in the sample plot were recorded by electronic total station, GPS and light intensity instrument. The community point map was drawn, the plant density, tree height, crown width and canopy height of E. sanguineus whose DBH was more than 5 cm in each plot. A sample of 20 m×20 m was randomly set in each plot to investigate the associated species and competitive species.

现阶段，在诸多因素的影响下，混凝土桥梁涵洞病害相对较多：（1）桥梁墩台的病害。桥梁墩台出现的病害裂缝，多呈现出竖向裂缝。此种病害现象，导致桥梁墩台的受力截面相对较小，桥梁基础在出现变形的情况下，容易导致盖梁出现裂缝，从而降低桥梁的整体承载力。（2）桥梁梁体的病害。桥梁梁体的病害，主要体现为梁体的表层老化、蜂窝、漏筋等，会在不同程度上降低结构的可靠性。此外，在病害严重时，可能会导致桥梁梁体的钢绞线崩裂，影响桥梁梁体的承载力。因此，应加强对混凝土桥梁涵洞病害的了解，提出具体的修补与加固措施[1]。

Table 8 Growth status of seedlings under different light intensity

CommunityItemLightintensity1/5light1/4light1/3light1/2lightFulllight1Growthstatus+++++++++++++++2+++++++++++++++3+++++++++++++++4+++++++++++++++

Note: + slow growth；++ relatively slow growth；+++ average growth；++++ relatively good growth；+++++ good growth.

As shown in Table 2, in the investigation of the habitat conditions of the E. sanguineus population, it was found that the distribution of the community was mainly concentrated on the south bank of the Yarlung Tsangpo River valley. Its topography is mainly the hillside forest edge and thicket, and the soil types are mainly mountain brown soil, mountain cinnamon soil, and sandy loam soil. In the investigation, it was found that the four communities were distributed far apart, in the form of multiple separated fragments, and the area of each patch was very small. This makes the individuation and differentiation of the communities can not be exchanged and complemented, which is not conducive to the development of the population.

Table 9 Growth status of seedlings in different acidic soils

ItempH5．45．86．26．66．8Growthstatus+++++++++++++++++++

Note: + slow growth；++ relatively slow growth；+++ average growth；++++ relatively good growth；+++++ good growth.

5.3.3 Allelopathy experiment on leaf litter. In order to verify whether leaf litter is the key factor of seedling death, a leaf allelopathy experiment was designed. Allelopathy refers to the interaction of biochemical substances among plants, and allelopathy has autotoxicity function. Autotoxicity among the same species is a mechanism for avoiding intraspecific competition derived from plant’s long-term adaptation to the environment and evolutionary selection[21].

敲了三下门，老陈以京剧念白的腔调说，小马，是我。一楼的老陈。我不作声，手握着门把手。老陈又说，我知道你在，把门开开。我把门开了，因为用力过大，门框发出咣当一声响，把老陈吓一跳。老陈后退一步，说咋了，你可是好几天没出门了。老陈的一只手拎着一条内裤，确切地说他是用两个手指捏着那条内裤的，他抬高手臂，那条黑色的女人内裤就晃了一下。

Table 10 Experimental results of allelopathy

Concentration∥%Culturetime∥d123456789100LeafwiltingBranchandleafwitheredDied75LeafwiltingSteminitiallylodgingStemcompl⁃etelylodgingBranchandleafwitheredDied50NormalLeafwiltingLeafwiltingcompletelyStempartiallylodgingStemcompl⁃etelylodgingBranchandleafwitheredDied25NormalNormalNormalLeafwiltingLeafwiltingcompletelyStempartiallylodgingStemcompl⁃etelylodgingBranchandleafwitheredDiedClearwaterNormalNormalNormalNormalNormalNormalNormalNormalNormal

6 Conclusions and discussions

Taken together, it is known that: (i) The climatic and environmental conditions in the habitat of E. sanguineus were very bad, and the habitat was fragmented and spaced. (ii) The population development was influenced by competitive and associated species. Appropriate shrub encirclement reduced the disturbance of human and livestock and provided good growth space and resources, so that they could grow better. The protective layer established for the population was disturbed and destroyed by human and livestock. It was found that the natural habitat of E. sanguineus had been fragmented, and the growth of individuals, seed germination and seedling survival in the population had been greatly destroyed. (iii) The population was small, the density was small, and there were many adult plants but few young plants; the seed-setting ability was low, seed quantity of fruit was small, and disease and pest were serious; the seed movement ability was weak, germination probability was low, there were very few seedlings, and the population structure was in serious unbalance. (iv) The seed germination rate was greatly reduced by the autotoxicity of the substance in the leaves, and the seedlings died out under the autotoxicity. The autotoxicity of the litter was the key factor for the seedlings to die.

According to the investigation and statistics of habitat condition, population structure, seed-setting ability, seedling survival and the experiment of the key factors of seedling death, it was found that the main reasons for the population decline were as follows: (i) The E. sanguineus population was too small, and the survival area was too small, which seriously affected the interspecific mating and seed development and regeneration, and greatly reduced the genetic diversity within the population. (ii) The dry and hot river valley climate and human and animal activities in the investigation area inhibited the seed germination and seedling growth of E. sanguineus, resulting in very low survival rate of seedlings and hindering the population expansion of E. sanguineus. (iii) The distribution area is located in the Yarlung Tsangpo river valley where the natural habitat fragmentation has affected the interspecific gene exchange, leading to the low seed-setting ability and germination rate of E. sanguineus, which is the direct cause of its population decline. (iv) The litterfall of E. sanguineus had autotoxicity, which inhibited the growth of seedlings under the forest, caused slow natural regeneration of the population, and then caused the population of E. sanguineus to be unable to spread and develop.

The flower, fruit and leaf of E. sanguineus are graceful in shape, elegant, bright and changeable in color, which has great application value in garden. The potential of medicine, chemical industry, energy, environmental protection and other values of the plants of EuonymusL. also bring power to the research and development of E. sanguineus. Therefore, the investigation and study of its habitat adaptability and the reason of population decline can provide a theoretical basis for the future rational collocation of habitat conditions and species to make its landscape application and environmental protection better, and provide a theoretical basis for its species protection, breeding technology, large-scale introduction and cultivation, as well as the study of its exploitation and utilization.

经过治疗1～4次的治疗后，疣体面积减少小于50%的患者占比为41%、45%、43%、49%，当中疣体面积治愈百分之百的占比为10%、26%、24%、35%。面积减少小于50%的疣体占比为57%、52%、58%、56%，除此之外，疣体面积增大的百分比为27%、29%、28%和59%。

为了进一步分析我国地区产能过剩的影响因素特征，本文将中国分为东部、中部和西部进行分析，分别对3个地区进行回归分析，结果如表4所示。

In its follow-up work, attention should be paid to the following aspects: (i) It is necessary to increase the protection and management of E. sanguineus population, isolate, protect and improve its habitat, and reduce the habitat fragmentation caused by human and animal disturbance. (ii) The allelopathic autotoxin and its effect on seed germination and seedling growth should be further studied. (iii) The best method of seed germination and cuttage should be selected to protect the species of E. sanguineus and make it multiply in large area, then make it come back to its original habitat, and make it develop normally, so as to expand the population scale. (iv) The value potential of E. sanguineus should be studied and exploited to maximize its potential.

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About WAEA

WAEA is a non-profit corporation. Members of WAEA are primarily from western United States and Canada, but anyone with an interest in agricultural and resource economics is welcome to join. It has over 600 members who are professional economists working in academic institutions, government agencies and departments, private industry and agribusiness, and non-governmental organizations.

The primary goals of WAEA are:

to foster the study and understanding of agricultural economics and its application to problems in the western United States and Canada; to promote unity and effectiveness of effort among all concerned with those problems; to promote improvement in the professional competence and standards of all members; to cooperate with other organizations and institutions engaged in similar or related activities; and to increase the contribution of agricultural economics to human welfare.

WAEA is governed by the State Wisconsin laws for incorporated organizations, the WAEA Articles of Incorporation, WAEA Bylaws and the WAEA Operating Policies.

刘雁衡无聊地看雾的运动变迁，直到它们渐渐不见。就在白雾即将散尽之际，一阵尖利的呼啸，由远及近而来，仿佛要撕裂什么。这种刺耳的声音，刘雁衡一干人并不感到陌生。城市里，这怪物惯于东蹿西跳，将乱糟糟的破城扯得破布一般。但这次，这怪物来得很是古怪，吱的一声，警车居然刹在他们诗社门口。