不同固定剂对扫描电镜生物制样效果的探讨

本文用福尔马林、卡诺液、戊二醛、戊二醛－－锇酸固定植物根尖作扫描电镜观察，以找出节省药品的良好固定剂．其结果是：福尔马林或戊二醛固定的材料与戊二醛－－锇酸固定的相比差别不甚明显，其组织结构及图象仍较清晰，而卡诺液固定的材料收缩显著．我们认为：作一般扫描电镜观察可以不用价格昂贵的锇酸固定材料．

医学生学习透射电子显微镜生物制样技术必要性研究

透射电子显微镜是医学院校利用率较高的大型仪器设备之一,由于设备昂贵、对制样技术要求较高等原因,现主要被用于科研工作。为提高医学生的专业素养和科研能力,在对外开放实验教学中开展透射电子显微镜生物制样技术的学习,通过课堂示教、集体观摩等方式,让学生掌握生物制样过程、制样要点、在实际工作中的意义等,为医学生步入临床和科研工作打下基础,也为大型仪器设备进入医学生实验教学提供经验交流。

Economic Value Evaluation of Wetland Service in Yeyahu Wetland Nature Reserve,Beijing

Based on multi-source data,this paper evaluated the economic value of ecological services in the Yeyahu Wetland Nature Reserve,Beijing,China.The ecological services of wetland included gas regulation,water quality im-provement,biodiversity maintenance,erosion control,water supply,recreational opportunity,raw material supply and existence value.Multiple conventional evaluation methods were used to calculate the value of eight wetland services.The results showed that significant values came from biodiversity maintenance and recreational opportunity.The main reasons were as follows.Firstly,Yeyahu Wetland Nature Reserve was the habitat for migrant birds,and government had payed more efforts to protect precious birds.Secondly,the population is large in Beijing.People enjoyed going outside and enjoyed the natural and artificial wetland scenes.At the same time,most people were prepared to pay for wetland conservation.The decline of vegetation cover made the economic value of erosion control the lowest.While the shrink of water resource and the deteriorative water quality caused the economic value of water supply lower.The evaluation results could help decision-makers understand the present status of the Yeyahu Wetland Nature Reserve and provide a scientific basis for strategic decision.

A Mechanism for Biological Control-Tempo-Spatial Synchronization of Natural Enemy and Insect Pest Population Dynamics at the Peak by Increase of Biodiversity

To reveal the mechanism of control of the Woolly Apple Aphid （Eriosoma lanigerum Hausm, WAA） by increase of biodiversity in the apple orchard, a consecutive two-year field trials were conducted in Yurman province, China. The results showed that the peak of natural enemy density curve in the cover cropping orchard was well temporally synchronized with that of the WAA density on trees, but did not synchronize with that of WAA density on trees in clean orchard. In addition, the frequency of natural enemies and WAA within a same sample in cover cropping orchard was obviously higher than that in clean cultivated orchard during the peak of population curves, indicating that natural enemies spatially synchronized with aphids. The density of WAA for the whole growing season in cover cropping orchard was much less than that in clean orchard. Therefore, the temporal-spatial synchrony of natural enemy and aphid populations was proposed as one of the mechanisms for aphid control in cover cropped orchards.

Effect of Radiant Energy Vacuum on Physical and Microbial Properties of Beef Jerky

To test the feasibility of radiant energy vacuum （REV） dehydration, a technology that couples microwave cooking with vacuum pressure, on beef jerky preparation, the physical and microbial properties of the final jerky product was compared to conventional preparation methods. Physical characteristics assessed using puncture and shear tests of samples prepared using REV dehydration compared to the traditional method were not statistically different （P 〈 0.05）. Moisture content and water activity levels were also very similar between the two products, To test microbiological quality, samples were homogenized in a stomacher and a variety of 3 M Petrifilms were used to evaluate the microbial load. Raw beef harboured low numbers of microbes, but the post-marination pasteurization/smoking step used in both treatments eliminated all culturable microorganisms tested for. To further investigate the ability of REV dehydration to kill microbes, samples were spiked with Listeria innocua after the pasteurization/smoking step but prior to REV dehydration. Samples were taken at different time intervals for microbial enumeration, and a decimal reduction time of 1 min was calculated, with 99.99% of 1.98 × 10^7 CFU g^-1 Listeria being killed in five min. Improved drying times were observed for jerky samples prepared using the REV method offering potential energy savings during jerky preparation.

Effects of Alternative Nitrogen Management Regimes on Production of Eucalyptus in Tropics and Sub-tropics

This paper presents the effects of alternative nitrogen management regimes on production of Eucalyptus in tropics and sub-tropics carried out in autumn, 2011. The aim of the study was to review alternative nitrogen management regimes that could enhance the positive effects and reduce negative effects of different Eucalyptus species in the perspective of smallholders. Literature review was used to survey the alternative nitrogen management regimes on eucalyptus trees. There was a significant improvement （P ≤ 0.01） in mean annual increment （MAI） as measured at seven years of Eucalyptus tereticornis in the plots planted with only legume, pueraria and stylosanthes, compared to that of the control on altitude 150 m and rainfall of 2,000 mm at the age of seven years, The MAI of Eucalyptus urophylla and Eucalyptus camaldulensis in plots planted with beans and rice shows a significant improvement （P ≤ 0.05） over the control treatment. Only the plots treated with nitrogen fertilizer 550 kg/ha showed significant improvement （P ≤ 0.05） in terms of MAI of Eucalyptus nitens, compared to the control treatment. In general, it can be concluded that as these alternative management regimes enhance productivity of Eucalyptus woodlots, the challenge for the small-scale farmers is on how to manage them sustainably. Therefore, forest policies that take consideration of increasing production of Eucalyptus and managing biodiversity with reference to these alternative management regimes should be developed in tropics and sub-tropics.

Intellectual Property Rights on Plant Genetic Resources:Perspective from Economics

Given the existence of transaction costs,the location of property rights is an important factor in determining the incentives for efficient levels of investment at various levels of the industry.This paper applies some of the economic theories of property rights and industrial structure to the issues concerning the conservation of biodiversity.Although the expansion of Intellectual Property Rights (IPR) systems into the area of genetic resources has increased private investment in R&D process of the agriculture,it does not generate enough incentives for in situ conservation of biodiversity.To solve this economic inefficiency,farmers'rights and other design of incentives and institutional arrangement should be reconsidered.

The Challenge of Crafting Institutions for the Commons： The Case of Community Forestry Support Programs in Mexico 2003-2008

Mexico forest tenure structure is known worldwide for its progressive approach of giving local communities full property rights to set a robust support to sustainable livelihoods in forested areas. Most forest areas in Mexico are owned by local communities either through the ejido, agrarian indigenous community or groups of small owners. In the last 30 years, many forest communities explored forest production at a commercial scale, creating their own communal forestry business and concurring to national markets with their timber and non-timber products. The socio-economical impacts of this approach were tremendous, steadily improving communities living standards. This success prompted rural organizations to ask the Mexican government to launch programs to expand the ＂community forestry＂ model. With international assistance from the World Bank and other agencies, the government of Mexico launched three different programs to foster forest commons： the Forest Conservation and Management Program, the Indigenous, Communities and Biodiversity Project and the Mexican part of the Mesoamerican Biological Corridor. Performance of these programs has been assessed through the World Bank evaluation framework, but the question about their environmental impact or even about their environmental sustainability and therefore their validity as national policies has been scantily explored and practically not debated. To contribute to answering these questions, the author made an extensive analysis of their impact over forest cover during the 2003-2008 period using land cover maps and correlated them with institutional development variables, building a social organization and collective action index （SOCAI）, following Elinor Ostrom institutional analysis and development framework （lAD）.

Assessment of Soil Quality Using Microarthropod Communities Under Different Land System： A Case Study in the Mid-Hills of Central Nepal

The study aimed to evaluate soil quality using microarthopods density, diversity and soil biological quality index （QBS-ar） under different land use systems and elevation gradients. A secondary aim was to determine the relationship among soil biological and physiochemical indicators. Three groups of soil microarthropods were recognized viz. （1） Collembola （38%） （2） Acarina （33%） and （3） other microarthropods （29%）. ANOVA indicated that total microarthropods densities differed significantly with land use and elevation. Population density of Acarina and other mieroarthropods were weakly significant different according to land use, while Collembola and Acarina densities showed highly significant difference with elevation. Total microarthropods, Acarina and Collembola densities were positively significantly correlated with soil organic carbon （SOC） and moisture but negatively correlated with bulk density, pH and temperature of the soil. SOC and soil moisture appeared to be good indicators of soil quality as reflected by the higher density and diversity of soil total microarthropods, Collembola, Acarina and other microarthropods group. The use of microarthropods for soil quality assessment could be effective and relatively inexpensive tool; however, further research is required to evaluate the impact of agricultural practices and elevation gradient on soil microarthropods density, diversity and species composition for the sustainable management of agro ecosystems.

A database of global wetland validation samples for wetland mapping

A database of global wetland validation samples （GWVS） is the foundation for wetland mapping on a global scale. In this work, a database of GWVS was created based on 25 “wetland-related” keyw ord searches of a total of 3,506 full-text documents downloaded from the Web of Science. Eight hundred and three samples from a total of 68 countries and 14i protected areas were recorded by the GWVS, including samples of marine/coastal wetlands, inland wet- lands and human-made wetlands, at ratios of 53 %, 41% and 6 %, respectively. The results exhibit spatial distribution among Terrestrial Ecoregions of the World, the World Database on Protected Areas and the Database of Global Administrative Areas. Within most of the biomes, protected areas and countries examined, the very low concentration of samples requires more attention in the future. The greatest concentration of samples within a single biome is found in the tropical and subtropical moist broadleaf forest biome, accounting for 27 % of the total samples, while no sample is found in the biome of tropical and subtropical coniferous woodland. Greater efforts are expected to be made to record samples in Oceania, Central Europe, Northern Europe, Northern Africa, Central Africa, Central America, the Caribbean, and midwestern South America. Our data show that it is feasible to map global wetlands using Landsat TM/ ETM＋ at 30-m resolution. The continued improvement of the GWVS sharing platform should be reinforced in the future, making a strong contribution to global wetland mapping and monitoring.