A comparison of regression methods for estimating soil-atmosphere diffusion gas fluxes by a closed-chamber technique

Continuous changes in methane (CH₄) and carbon dioxide (CO₂) concentrations inside a closed chamber were measured on the forest floor at three sites: a deciduous forest and a coniferous forest in Hokkaido, Japan, and a birch forest in West Siberia, Russian Federation. Flux estimations by three types of regression methods, exponential, nonlinear, and linear, were examined using field-collected concentration data. The pattern of change with time of the gas concentration in the headspace differed, mainly according to site but also, to a lesser extent, according to the gas. This was a function of both the chamber height and surface soil property relating to soil gas diffusion and the gas concentration profile. Flux estimations did not differ statistically between the exponential and nonlinear methods for either gas at any site, because both of those regression methods were based on diffusion theory. However, the flux values estimated by linear regression were significantly different from those estimated by the other two methods for both CH₄ and CO₂ at the deciduous forest site and for CO₂ at the coniferous forest site. Shortening the chamber deployment period improved the linearity of the curve, but did not completely eliminate the error. Our results suggest that linear regression is not a good model of the change in headspace concentration with time.     

Naidid worms (Oligochaeta, Naididae) in paddy soils as affected by the application of legume mulch and/or tillage practice

Reproduction, intrinsic rate of natural increase and population density of naidid worms were investigated in submerged paddy fields and the laboratory. No tillage plus legume-mulching increased the population density of naidid worms. Soil treatments with neither tillage nor legume mulch, and tillage practice alone, did not increase the number of worms. Dero dorsalis Ferronnière was dominant in soil of the no-tillage treatment. In laboratory experiments, legume-mulching with the proper amount of dissolved O₂ accelerated asexual reproduction of D. dorsalis through zooid budding. For the legume and aeration treatment, (N_i+1-N_i) N_i^-1 values (where N_i and N_i+1 are the populations at times t=i and t=i+1) were plotted against N_i+1. Utilizing this linear relation, this data fitted the logistic curve (r²=0.885, P<0.05). Based on the linear relation, the intrinsic rate of natural increase (r), carrying capacity (K), and doubling time (T) were calculated as 0.2125 day^-1, 12,666 m^-2, and 3.26 days, respectively. The amounts of legumes applied were highly correlated with the population of D. dorsalis, indicating that the weight of legume is a limiting factor with respect to carrying capacity. A literature review indicated a significant correlation (P<0.01) between intrinsic rate of natural increase and maximum body length of naidids with temperature conversion of the growth rate. Sexually mature worms were rarely found in submerged paddy fields. Sexual reproduction seems to be adopted in response to soil desiccation after paddy field drainage.     

Dynamical niche sets-based cooperativeevolutionary algorithm for job shop scheduling

Job shop scheduling is an important part of manufacturing process. Pre-mature, local optimal solution or low convergence rate of Genetic Algorithm may come across in solving scheduling problem in multi-Job shop. To avoid those unhealthy tendencies, this paper introduced the Dynamical Niche Sets-based Cooperative Evolutionary Algorithm model.In the Algorithm, Process-based chromosome encoding method was used; the crossover operator and mutation operator were designed to adjust operation sequences and choose process routes. The cooperative scheduling problem in multi-Job shop was solved using dynamical niche sets technology and multi-population cooperative evolution method. The Experiment result shows the proposed method has good advantages.     

山体断面绿化植物的选择、配置及种植措施

就当前高速公路等施工形成的山体断面绿化难题进行了探讨，重点推荐了华东地区适用的爬山虎、络石、薜荔、常春油麻藤、凌霄等20余种优良垂直绿化植物，并分别对其生长特性、优缺点和绿化效果等方面作出了客观评价，同时根据山体断面不同坡度、高度、平整度、基质及植物习性和生境等分别阐述了植物配置原则和具体种类，还提出了栽植中可采取的一些必要的辅助措施。参8     

长龄壮秧超稀植杂交稻生长和产量状况研究

[目的]了解长龄壮秧对超稀植杂交稻生长和产量的影响。[方法]设T1(30d)、T2(42d)T3(54d)3个秧龄处理,研究B优827、岗优725和D优527超稀植时的生长及产量情况。[结果]随着秧龄的延长,3个品种的最高分蘖期推迟。同一品种不同处理的单株最大茎蘖数无明显差异。岗优725的平均单株有效穗数为T1>T2>T3,其余两品种的为T2>T1>T3。3个品种T3处理的二次分蘖穗占总有效穗的比例下降,三次分蘖穗的比例增加。B优827和D优527的实收产量为T1>T2>T3,岗优725的为T2>T1>T3。不同品种对秧龄长短的反应有明显差异。[结论]秧龄对超稀植杂交稻的分蘖动态、有效穗及其组成、经济性状和产量都有一定的影响。在良好管理的基础上,合理选用品种,长龄壮秧超稀植杂交稻仍能保持高产水平。     

利用拮抗木霉菌防治立枯病的研究

从吉林、黑龙江、北京、天津等地采集土样28份，经室内分离纯化后得到木霉菌（Trichoderma.spp)菌株60个，以立枯比丝核菌为供试病原菌，通过对峙培养筛选出1株对立枯丝核菌有强拮抗作用的木霉菌菌株，将其孢子悬液对茄苗不同时期进行人工接种测定其对立枯病的防治，结果表明：这种拮抗木霉菌对茄子苗期立枯病人明显的防治效果，子叶期防效达73．3％，真叶期防效达71．34％。     

Study on polymorphisms of microsatellite DNA of six Chinese indigenous sheep and goat breeds

The genomes of six populations were screened using microsatellites as molecular markers, including Ujmuqin sheep, small-tailed Han sheep, Tan sheep, Hu sheep, Tong sheep and Yangtse River Delta (YRD) white goat. A total of seven microsatellite markers were used and genetic diversity and genetic distance were also determined. The results showed that there were 224 alleles in six populations, all seven loci showed polymorphism in all populations. The average heterozygosity of all populations was 0.949 9, and the mean polymorphism information content (PIC) of all six populations was 0.842 5–0.929 4. The six sheep (goat) popualtions were lowly differentiated with all loci, and the coefficient of phaenotype differentiation (Fst) was 2.6%, which was consistent with the coefficient of gene differentiation (Gst). The global heterozygote deficit across of all populations (Fit) amounted to 0.5%. The overall significant deficit of heterozygotes because of inbreeding within breeds (Fis) amounted to −2.2%. Two Unweighted Pair-group Method using Arithmetic Averages (UPGMA) dendrograms were constructed on the basis of Nei’s standard genetic distance (DS) and Nei’s genetic distance (DA) respectively. Hu sheep and Tong sheep were grouped at first, Ujmuqin sheep and small-tailed Han sheep clustered and then clustered with Tan sheep. Finally, Yangtse River Delta white goat joined in with all above. From this study, Ujmuqin sheep belongs to “Mongolia sheep” group, which corresponds with the historical records exactly. Ujmuqin sheep and small-tailed Han sheep, Tan sheep, Hu sheep and Tong sheep all vest in the “Mongolia sheep” group.     

面向新世纪的校风建设

指出了校风建设的意义和原则，提出了建设良好的学生学风、教师教风和工作作风的要求、途径和方法。