太平洋深海沉积物来源的菌株Tenacibaculum sp.HMG1对孔雀石绿降解特性的研究

本文在太平洋深海沉积物中分离得到一株孔雀石绿降解菌株,鉴定命名为Tenacibaculum sp.HMG1。通过菌株生长实验和高效液相色谱的研究表明, HMG1菌株可以在20 mg/L的孔雀石绿中维持较快的生长速率,并且在12 h内可降解98.8%的孔雀石绿,这证明该菌株具有很高的孔雀石绿耐受能力和降解活性。通过基因组测序在HMG1菌株发现一条过氧化物酶基因可能参与了孔雀石绿的降解,随后利用原核表达获得了相应的重组蛋白。实验表明,该重组过氧化物酶具有极强的活性,可在1000 mg/L的孔雀石绿中发挥降解功能。本文利用液相色谱-质谱联用（LC-MS）技术对孔雀石绿的菌株降解产物和重组酶降解产物进行鉴定,并基于鉴定结果推测了两种降解途径。结果发现两种降解方式存在共同的降解途径。此外,孔雀石绿降解条件的实验结果证明重组过氧化物酶可以在低温（20℃）、复杂的pH值（6.0–9.0）、高盐度（100 mmol/L）、金属离子和EDTA等反应条件下依旧维持很高的孔雀石绿降解活性。以上实验结果表明,HMG1菌株和重组过氧化物酶均在孔雀石绿污染生物修复方面具有很大潜力。     

鲫鱼(Carassius auratus)半胱亚磺酸脱酸酶CSAD基因克隆及其表达研究

本研究以鲫鱼(Carassius auratus)为研究对象,采用巢式PCR和RACE技术克隆鲫鱼半胱亚磺酸脱酸酶CSAD基因c DNA序列,并且利用实时荧光定量PCR检测了CSAD m RNA在鲫鱼不同组织和昼夜节律中的相对表达水平,同时还研究了牛磺酸对鲫鱼肠道CSAD m RNA表达的影响。结果表明:(1)鲫鱼CSAD基因c DNA序列包含186bp的5?UTR序列,675bp的3?UTR序列,1503bp开放阅读框,编码500个氨基酸。同源性分析表明,鲫鱼和鲤鱼的同源性为97.2%。系统发育分析表明,鲫鱼与鲤鱼之间的亲缘关系最接近,置信度为100。经预测,其编码的蛋白质的分子量和等电点分别为56.82k Da和5.77;(2)Ca CSAD m RNA在肌肉、心脏、肠道及肝脏中的表达水平较高,在脑和鳃组织中的相对表达量较低;(3)鲫鱼肠道CSAD m RNA的相对表达量在6:00am点时最高,9:00pm点时相对表达量最低;(4)鲫鱼CSAD的相对表达丰度随着牛磺酸添加量的增加而逐渐下降。本研究结果不仅有助于理解鲫鱼CSAD基因的分子特征,同时将为进一步研究鱼类CSAD营养调控功能提供理论依据。     

Walking Access Distance of Metro Passengers and Relationship with Demographic Characteristics: A Case Study of Nanjing Metro

In the metropolises of China, the metro plays an increasingly important role in commuting because of its efficiency, affordability, and cleanliness. This paper attempts to explore the relationship between walking access distance to metro stations and the demographic characteristics of passengers, such as age, monthly income, travel frequency, gender, and travel purpose, as well as the influence of the urban context. Nanjing Metro Line 2 is selected as the case study. By using different methods such as a questionnaire survey, spatial decay function, analysis of covariance (ANOVA), network analysis of routes, and K-means cluster analysis, it is suggested that demographic characteristics have a significant impact on the pedestrian walking distance, with the exception of gender. Furthermore, the paper finds a spatial decay effect in walking access distance, the decay rate of which, however, varies across stations. Terminal stations have a larger pedestrian catchment area than in regular and exchange stations. Moreover, the passengers of Nanjing Metro Line 2 can be classified into six groups according to their demographic characteristics, among which education and occupation are vital indicators in determining their willingness to walk to the stations. Middle-class passengers have a higher dependence on the metro and tend to walk longer than other groups do. This study provides an important reference for planners and transport sectors to optimize land-use and transport infrastructures.     

Spatial patterns in natural <Emphasis Type="Italic">Picea crassifolia</Emphasis> forests of northwestern China,as basis for close-to-nature forestry

Close-to-nature forest management has been proposed as an effective method for improving the quality of plantation forests. Knowledge of spatial distribution patterns, structure, and succession trajectories in natural forests can provide guidelines for the establishment of close-to-nature forest plantations. Such knowledge is lacking in natural spruce (Picea crassifolia) forests in the Qilian Mountains of China, impeding the establishment of production forests. We conducted a case study in the Qilian Mountains to analyze the relationships between the naturally-formed forest patches and terrain factors, spatial heterogeneity of stand characteristics, and stand structure following harvesting disturbance. Our results suggested that spruce plantations will be effective on the N, NE, and NW slopes, at elevations between 2700 and 3300 m, and on slopes ranging from 15° to 45°. Further, planted forest patches should occupy 64% of the slope area on semi-shady slopes (NE, NW). Spatial patterns in the studied forest exhibited a strong scale-effect, and an area of 0.25 ha could be used as the most efficient plot scale for the management of spruce plantations. Partial logging is an effective method for the conversion of spruce planted forests into nearnatural forests, and the intensity of partial logging can be determined from the negative exponential function relationship between stand density and DBH. Our results provided critical information for the development of spruce plantations and conversion of existing plantations.     

Spatial distribution of snow depth based on geographically weighted regression kriging in the Bayanbulak Basin of the Tianshan Mountains,China

Snow depth is a general input variable in many models of agriculture,hydrology,climate and ecology.This study makes use of observational data of snow depth and explanatory variables to compare the accuracy and effect of geographically weighted regression kriging(GWRK)and regression kriging(RK)in a spatial interpolation of regional snow depth.The auxiliary variables are analyzed using correlation coefficients and the variance inflation factor(VIF).Three variables,Height,topographic ruggedness index(TRI),and land surface temperature(LST),are used as explanatory variables to establish a regression model for snow depth.The estimated spatial distribution of snow depth in the Bayanbulak Basin of the Tianshan Mountains in China with a spatial resolution of 1 km is obtained.The results indicate that 1)the result of GWRK's accuracy is slightly higher than that of RK(R~2=0.55 vs.R~2=0.50,RMSE(root mean square error)=0.102 m vs.RMSE=0.077 m);2)for the subareas,GWRK and RK exhibit similar estimation results of snow depth.Areas in the Bayanbulak Basin with a snow depth greater than 0.15m are mainly distributed in an elevation range of 2632.00–3269.00 m and the snow in this area comprises 45.00–46.00% of the total amount of snow in this basin.However,the GWRK resulted in more detailed information on snow depth distribution than the RK.The final conclusion is that GWRK is better suited for estimating regional snow depth distribution.     

Solar GLAO and TAO:performance comparisons

Multi-conjugate adaptive optics(MCAO),consisting of several deformable mirrors(DMs),can significantly increase the adaptive optics(AO)correction field of view.Current MCAO can be realized by either star-oriented or layer-oriented approaches.For solar AO,ground-layer adaptive optics(GLAO)can be viewed as an extreme case of layer-oriented MCAO in which the DM is conjugated to the ground,while solar tomography adaptive optics(TAO)that we proposed recently can be viewed as star-oriented MCAO with only one DM.Solar GLAO and TAO use the same hardware as conventional solar AO,and therefore it will be important to see which method can deliver better performance.In this article,we compare the performance of solar GLAO and TAO by using end-to-end numerical simulation software.Numerical simulations of TAO and GLAO with different numbers of guide stars are conducted.Our results show that TAO and GLAO produce the same performance if the DM is conjugated to the ground,but TAO can only generate better performance when the DM is conjugated to the best height.This result has important application in existing one-DM solar AO systems.     

徐州市水土流失时空变化研究

本文以3S技术为支撑,在修正水土流失方程（RUSLE）的基础上,针对徐州黄泛平原-丘陵地带的特殊地形地貌、对2000年以来徐州市水土流失时空变化特征进行了分析。结果表明：2000-2014年徐州市土壤侵蚀等级以微度为主,微度侵蚀面积占总侵蚀面积多年平均达到76.34%;中度侵蚀次之,所占比例在10%~17%间;剧烈侵蚀所占比例最少。轻度及以上土壤侵蚀等级主要发生在中部微山湖下游、京杭大运河一带的丘陵岗地地区、主城区与故黄河北岸的黄泛平原地区,以及丰县、新沂、邳州的局部区域;土壤侵蚀存在一定程度年际变化特征,睢宁、丰县、邳州的部分地区侵蚀面积年际变化较为明显,土壤侵蚀总面积整体上呈现下降趋势。     

基于随机序列GPS数据集的用户位置挖掘方法研究

数据挖掘是指从大规模的数据中抽取非平凡的、隐含的、未知的、有潜在使用价值信息的过程。LBS系统记录了大量的移动端用户在真实世界中的空间和时间属性,如果能从这些记录中挖掘出移动端用户的常用位置信息及其特点,可以使我们更好地理解用户,更好地为用户服务。本文根据LBS系统记录的移动端用户位置信息,利用改进的DBSCAN聚类算法,较为准确地提取移动端用户的常用位置信息,并通过实例验证该方法的可靠性。     

Evolution Characteristics of Government-Industry-University-Research Cooperative Innovation Network for China’s Agriculture and Influencing Factors: Illustrated According to Agricultural Patent Case

Under the special background of China, the cooperative innovation between different government-industry-university-research institutes plays an increasingly important role in the agricultural field. However, the existing literature has paid little attention to it. Considering the cooperation patents, published in the agriculture field stemming from the Full-text Database of China Patents as the study object, the spatial and institutional attribute of the authors as the data source, and by combining the social network and spatial econometrics analysis, this paper analyzes the structure evolution characteristics of cooperative innovation networks of agricultural government-industry-university-research institute in the city level of China in 1985–2014, based on the triple helix theory, with the influence factors discussed. This shows that, 1) since 1985, China's agricultural innovation level has been substantially increased, but the development degree of the cooperative innovation network is low, and the patent cooperation mainly relies on authors in the same unit; 2) enterprises play a leading role in the agricultural cooperative innovation. The effect of the government and hybrid organizations driven by the government is not obvious; 3) the cooperative innovation in the province and city dominates, and a multi-pole pattern has been formed. The cooperative innovation network structure evolves from a single helix empty core and double helix multi core to a double helix hierarchical network; 4) the city's science, education funding and personnel investment are key factors determining the agricultural cooperative innovation, while the agricultural development of the city presents slight negative impacts on it. The spatial mismatch of supply and demand is present in the technical cooperative innovation of China's agriculture. Therefore, the science enhancement and education investment to big agricultural provinces should be promptly implemented.