水轮泵站改水电站问题的探讨

从水轮泵站、水电站、电灌站的效率关系,论证了水轮泵提水效率是最高的,并提出水轮泵站与水电站并存的最优方案.     

Response of Pinus Sylvestris Seedlings to Cadmium and Mycorrhizal Colonisation

Effects of Cd and mycorrhizal colonisation on seedling growth and Cd accumulation in Pinus sylvestris seedlings were studied. While colonisation by Suillus bovinus improved shoot growth, colonisation by Paxillus involutus had no effect on growth of seedlings. There was no Cd-ameliorating effect of colonisation in terms of either shoot or root growth. Colonisation by P. involutus did not decrease Cd transport from roots to shoots, whereas colonisation by S. bovinus significantly reduced the level of Cd in shoots in the 100 mg Cd kg^-1 treatment. The proportion of healthy mycorrhizal root tips of S. bovinus-inoculated seedlings was reduced as a result of Cd addition. However, no such effect was found in P. involutus-inoculated seedlings.     

Genetically manipulated pineapple: transgene stability, gene expression and herbicide tolerance under field conditions

Pineapple plants transformed with the bar gene for bialaphos resistance were evaluated for transgene stability, gene expression and tolerance to glufosinate ammonium, the active ingredient of the herbicide Basta^® X, under field conditions. Genetically modified plants of the cv. Phuket were micropropagated, rooted and established in a shade house before transfer to an experimental plot. Seven months after transfer to the field, plants were tolerant to 1600 ml/rai of the herbicide Basta^® X (stock concentration 15% w/v glufosinate ammonium), this being twice the dose recommended for field application of the herbicide. Genetically modified plants remained green and healthy following spraying with the herbicide. In contrast, non‐transformed pineapple plants of the same cv. became necrotic and died within 21 days of spraying with the herbicide at a reduced concentration of 800 ml/rai. Bar gene stability and expression in clonally‐derived plants were assessed by PCR, RT‐PCR and Southern analyses at 120, 210, 240, 270 and 380 days following transfer of the plants to the field. The bar gene was stable and expressed in transgenic plants throughout the duration of the trial. Fruit characteristics and yield were not affected by transgene introduction and expression. Transgenic plants tolerant to glufosinate ammonium should facilitate more effective weed control in pineapple plantations without damage to the crop.     

Relationships in pineapple by random amplified polymorphic DNA (RAPD) analysis

Random amplified polymorphic DNA (RAPD) analysis was applied to eight commercial cultivars of pineapple, two intergroup hybrids and two wild species. Morphologically, pineapple is divided into the Cayenne, Queen, Spanish, Maipure and Abacaxi groups. Members of the first three groups have been analysed in this study. The cultivars ‘Tradsithong’, ‘Phuket’, ‘Sawee’ and ‘Tainan’, with spiny leaves, form the Queen group. In ‘Pattavia’, ‘Nanglae’ and ‘Petburi no. 2’ (Cayenne group), spines are confined to the leaf tips. ‘Intrachitdang’ is normally placed in the Spanish group, which is morphologically similar to the Queen group, but with inferior quality fruit. DNA amplification products were compared from 16 arbitrary 10‐mer primers from which a dendrogram was constructed. The results confirmed morphological classifications for seven of the eight commercial cultivars, with the Queen and Cayenne groups as separate clusters. However, the cv. ‘Intrachitdang’ was more closely related to the Cayenne group. Two hybrids from reciprocal Cayenne × Queen group crosses, were more closely allied to the Queen group. The two wild species were outside the groups. RAPD analysis can be exploited to investigate relationships within pineapple germplasm.     

Animal medical genetics: a perspective on the epidemiology and control of inherited disorders

This perspective considers genetic disorders of domestic animal populations, in particular their epidemiology and control. Inherited disorders of animals share the same basic molecular biology as those of human beings, but they differ in their epidemiology due largely to the breed structure of the various species, human control of breeding and a greater influence of the founder effect, particularly due to extensive use of a limited number of sires, and inbreeding. Control of genetic disorders in animals is also more practical through extensive screening for disease, or heterozygous animals within defined breed populations, followed by exclusion of affected or carrier animals from breeding. This is assisted by the fact that, within a breed, many inherited monogenic disorders are associated with a single mutation. However some of the more important disorders may be inherited in a non-Mendelian manner, being influenced by multiple genes as well as environmental factors. These aspects are discussed and contrasted with similar aspects in human medical genetics.     

Downstream effects of hydroelectric dam operation on thermal habitat use by Brook Trout (Salvelinus fontinalis) and Slimy Sculpin (Cottus cognatus)

Hydroelectric dams can alter downstream water temperatures, impacting thermal habitat available for fishes. Decreases in river water temperatures resulting from hydroelectric dam operations may be beneficial to coldwater species and could potentially offset warming resulting from climatic trends. We used two coldwater fish species, Slimy Sculpin (Cottus cognatus) and Brook Trout (Salvelinus fontinalis) to assess the impact of a cool water draw below a 15 MW hydroelectric dam on fish thermal habitat use relative to a nearby naturally flowing river. Cooler water temperatures below the dam corresponded with significantly cooler mean growth season temperature use for Slimy Sculpin, but not Brook Trout, relative to the natural river. As well, mean growing season temperature use by Slimy Sculpin was significantly cooler relative to Brook Trout in both rivers, and significantly different amongst studied sites in the regulated river. Fish condition was significantly correlated with temperature use for Slimy Sculpin in the naturally flowing river only. Our results indicate that manipulating river water temperatures through hydroelectric dam operations to benefit multiple fish species will be difficult given the complexity of riverine thermal habitat and species‐specific differences in thermal preferences and behaviour.     

Synthetic retinoids in veterinary dermatology

The synthetic retinoids, isotretinoin (Accutane) and etretinate (Tegison) are vitamin A analogs. They affect epithelial differentiation and thus have potential for therapy for disorders of epithelial maturation such as keratinization defects of cutaneous neoplasia. The pharmacology, indications for use, clinical experience, potential toxicities, and recommended monitoring of these drugs are discussed.     

半导体消雷器应用技术

该文通过对县级３５ｋＶ电力系统应用半导体少长针消雷器的实践进行了研究，分析了在电力系统中采用两针式、五针式两种半导消雷器组合成单基、双基、多基联合保护网。尤其是对应用设计方面提出了具体的设计原理及方法，在实际运行中取得极好的防雷效果。为未来的高压线路特别是特高压线路应用设计半导体消雷器装置开辟了道路。