华北平原几种主要类型土壤的硝化及反硝化活性

取用华北平原5种主要土壤进行实验室培养试验,研究不同类型土壤间硝化反硝化活性的差异。结果表明,培养28h后砂姜黑土、潮土、褐土、盐渍土和风沙土的硝化率分别为7.9%、20.8%、46.4%、22.5%和20.3%;148h后砂姜黑土的硝化率为18.7%,其它4种土壤达98.4%—100%,基本硝化完全;培养268h释放的N2O总量分别为0.04、0.27、0.24、0.41和0.45μgN·g-1土。培养650h的反硝化损失量分别为0.6、0.3、0.08、0.02和0.05μgN·g-1土。可见,不同的土壤中砂姜黑土的硝化作用活性较弱,而反硝化活性较强;潮土、褐土、盐渍土和风沙土的硝化作用活性较强,而反硝化活性相对较弱。土壤的硝化及反硝化作用与土壤质地和pH有关,与硝化和反硝化菌数量无明显相关性。     

UASB的启动及其对畜禽废水处理的试验研究

利用UASB反应器处理畜禽废水的试验运行。结果表明，用畜禽废水直接启动UASB反应器是切实可行的，絮状污泥接种后经过54d的驯化，有机负荷由0．8kgCOD·（m^3·d）^-1提升到5kg COD·（m^3·d）^-1，进料COD浓度由800mg·L^-1提高到4000mg·L^-1，去除率基本稳定在85％以上；用UASB反应器处理畜禽废水也是切实可行的，畜禽废水经过UASB反应器处理，COD的去除率达到85％以上，同时对TN和TP也有一定的去除，且反应器较稳定，具有较强的抗冲击负荷能力。     

A selective activity-dependent requirement for dynamin 1 in synaptic vesicle endocytosis

Dynamin 1 is a neuron-specific guanosine triphosphatase thought to be critically required for the fission reaction of synaptic vesicle endocytosis. Unexpectedly, mice lacking dynamin 1 were able to form functional synapses, even though their postnatal viability was limited. However, during spontaneous network activity, branched, tubular plasma membrane invaginations accumulated, capped by clathrin-coated pits, in synapses of dynamin 1-knockout mice. Synaptic vesicle endocytosis was severely impaired during strong exogenous stimulation but resumed efficiently when the stimulus was terminated. Thus, dynamin 1-independent mechanisms can support limited synaptic vesicle endocytosis, but dynamin 1 is needed during high levels of neuronal activity.     

基于虚拟仪器的湿增压实验台测控系统研究

本文以湿增压动力装置实验台为物理模型，为进行相关实验完成了速度、流量、扭矩等重要参数的测量，并以N16221硬件为基础，基于虚拟仪器平台LabVIEW研制了实验台的测试软件。新设计的测试系统是基于虚拟仪器平台的模块化系统，使得研究人员的大部分精力集中于所要实现的功能上，而不是以往繁琐的算法和重复的编程上，参数易于修改，缩短了系统开发的周期，能满足实验需求。     

Effects of a short period of drought on changes in tuber volume and specific leaf weight. II. Diurnal changes

Summary Single-stemmed potato plants, cv. Bintje, were grown on a nutrient solution under controlled conditions. They were exposed to a short drought stress, or remained untreated. Short-term changes in tuber volume and in specific leaf weight were measured non-destructively. Tubers from control plants increased rapidly in volume during the night and did not grow, or even shrivelled during the day. Tubers of stressed plants did not show a uniform response; some tubers markedly declined in volume during the day. The patterns of volume increase of stressed plants became erratic after the stress, mainly because some plants never fully recovered. Patterns of diurnal fluctuation in tuber volume were similar to diurnal changes in specific leaf weight; tubers within the same stressed plant sometimes reacted differently. In these cases the effects on the diurnal fluctuation partly reflected the long-term effects, reported in an earlier paper.     

Mixotrophy in a Local Strain of Nannochloropsis granulata for Renewable High-Value Biomass Production on the West Coast of Sweden

A local strain of Nannochloropsis granulata (Ng) has been reported as the most productive microalgal strain in terms of both biomass yield and lipid content when cultivated in photobioreactors that simulate the light and temperature conditions during the summer on the west coast of Sweden. To further increase the biomass and the biotechnological potential of this strain in these conditions, mixotrophic growth (i.e., the simultaneous use of photosynthesis and respiration) with glycerol as an external carbon source was investigated in this study and compared with phototrophic growth that made use of air enriched with 1–2% CO₂. The addition of either glycerol or CO₂-enriched air stimulated the growth of Ng and theproduction of high-value long-chain polyunsaturated fatty acids (EPA) as well as the carotenoid canthaxanthin. Bioassays in human prostate cell lines indicated the highest antitumoral activity for Ng extracts and fractions from mixotrophic conditions. Metabolomics detected betaine lipids specifically in the bioactive fractions, suggesting their involvement in the observed antitumoral effect. Genes related to autophagy were found to be upregulated by the most bioactive fraction, suggesting a possible therapeutic target against prostate cancer progression. Taken together, our results suggest that the local Ng strain can be cultivated mixotrophically in summer conditions on the west coast of Sweden for the production of high-value biomass containing antiproliferative compounds, carotenoids, and EPA.     

Improved diagnosis of powdery scab (Spongospora subterranea f.sp.subterranea) symptoms on potato tubers (Solanum tuberosum L.)

Summary Based on visual inspection, discrimination between common scab (Streptomyces spp.) and powdery scab (Spongospora subterranea) can be difficult. Inspections are performed on unwashed samples, incidentally supported by microscopic examination. During 1994–1996 surveys were performed in The Netherlands on tubers with symptoms resembling common scab. Under microscopic assessment nearly all samples showed the presence of structures resembling cystosori (sporeballs) ofS. subterranea. At that time confirmation using alternative techniques was not possible. In 2003 research was undertaken to clarify the situation with respect to scab on potato tubers in The Netherlands. One hundred and eighteen scab samples were extensively tested forS. subterranea. All samples were digitally photographed, microscopically examinated and tested with real-time PCR and DAS-ELISA. Use of these modern methods resulted in a clear picture of symptoms that can be attributed toS. subterranea. A lot of scab samples with structures resembling cystosori could not be confirmed as contaminated withS. subterranea.     

PAMELA measurements of cosmic-ray proton and helium spectra

Protons and helium nuclei are the most abundant components of the cosmic radiation. Precise measurements of their fluxes are needed to understand the acceleration and subsequent propagation of cosmic rays in our Galaxy. We report precision measurements of the proton and helium spectra in the rigidity range 1 gigavolt to 1.2 teravolts performed by the satellite-borne experiment PAMELA (payload for antimatter matter exploration and light-nuclei astrophysics). We find that the spectral shapes of these two species are different and cannot be described well by a single power law. These data challenge the current paradigm of cosmic-ray acceleration in supernova remnants followed by diffusive propagation in the Galaxy. More complex processes of acceleration and propagation of cosmic rays are required to explain the spectral structures observed in our data.     

Effect of pre-planting temperature and light treatments of seed tubers on potato yield and tuber size distribution

Summary From 1985 to 1987 field experiments were caried out to test the influence of different pre-planting storage treatments on yield and size distribution of potato crops. The storage treatments included 4, 8 and 12°C in the light and in the dark, for different periods before planting. Subjecting the seed tubers to light at low temperatures induced crops to produce a larger proportion of smaller sized tubers while storing seed tubers at higher temperatures in the dark led to an increase of tubers >55 mm. These observations were confirmed in five field experiments with two cultivars at two sites and in three growing seasons.     

高产多抗两系杂交早稻株两优83的选育与应用

株两优83是湘潭市农科所用广亲和低温敏两用核不育系株1S为母本，以新育成的高产多抗广亲和品系潭早183为父本选配出的两系杂交早稻新组合。该组合具有苗期耐寒力强、中抗稻瘟病和白叶枯病、抗褐飞虱和白背飞虱、生育期适中、高产稳产性好等特性。2002年3月通过湖南省农作物品种审定。