改进PSO算法在电力系统无功优化中的应用

介绍一种改进粒子群的无功优化方法。采用简化粒子群优化方程和添加极值扰动算子两种策略加以改进,提出简化粒子群优化（SPSO）算法、带极值扰动粒子群优化（DPSO）算法,并将二者结合起来提出带极值扰动的简化粒子群优化（DSPSO）算法。以IEEE6节点系统为例进行无功优化计算,并与其他算法进行比较,结果表明：该算法具有较快的收敛速度及较强的全局搜索能力,可较好地解决电力系统的无功优化问题。     

我国西北平原地区林业生态服务功能评价

[目的]评价我国西北平原地区林业的生态服务功能。[方法]通过对西北平原地区林业的调查与监测,以县为最小单位,采取普查与典型调查相结合的调查方法,在评价上利用物质量评价法对西北地区平原林业的生态服务功能进行了评估。[结果]2005年西北地区平原林业在涵养水源、保持土壤、植被固碳、土壤固碳、植被制氧、吸收二氧化硫和滞尘方面均发挥了巨大作用,其各自生态服务功能值分别为32075.8万m3/a、2.8×106、1254、2752.8、3354.3、53.0和8510万t/a。[结论]为我国西北地区平原林业的生态服务功能研究奠定了基础。     

中亚热带常绿阔叶林林隙与物种多样性的关系研究

对万木林中亚热带常绿阔叶林非林隙与林隙内物种多样性及物种多样性随林隙大小的变化规律研究结果表明 ,万木林常绿阔叶林林隙内物种多样性高于非林隙内 ,乔木树种物种多样性随林隙大小的变化呈双峰曲线 ,其物种多样性为 2 0 0～ 30 0m2 面积林隙内达最大值 ;而灌木树种多样性随林隙大小的变化呈单峰曲线 ,其物种多样性为 4 0 0～ 5 0 0m2 面积林隙内达最大值。     

The effect of the host's age on the pathology of Eimeria stiedai infection in rabbits

The pathology of experimental Eimeria stiedai infection in 2- and 4-month-old rabbits raised coccidia-free was studied. Over 50 days of infection, the serum activities of aspartate (AST) and alanine (ALT) aminotransferases, alkaline phosphatase (AP) and gamma-glutamyltranspeptidase (GGTP) were analyzed as indicators of hepatic lesions and total serum globulins with respect to the immune response of the host; parasite development was followed by oocyst output; weight gain, food intake and relative liver weight were analyzed to control the performance of infected animals. The age of the host strongly affected parasite development and consequently the biochemical and zootechnical parameters differed more markedly in the younger animals; however, the enzyme ALT showed an increase independent of parasite development, and infection did not affect GGTP activity. The increase in age was responsible for resistance of rabbits to hepatic coccidiosis and older animals were less affected than young ones.     

不同水分条件下苔藓结皮光合能力对氮素添加量的响应

[目的]探究苔藓结皮失水过程中光合能力对不同梯度氮添加的响应,为进一步研究苔藓结皮对氮沉降的响应过程以及为干旱、半干旱区荒漠生态系统的管理提供理论依据。[方法]选取毛乌素沙地的优势藓种拟双色真藓(Bryum pachytheca)为研究对象,在控制条件下采用氮添加的模拟试验手段。[结果]苔藓结皮净光合速率在低于0.2g/(m2·a)的氮添加量时受到促进,在高于0.2g/(m2·a)的氮素添加量下,低水分含量时被抑制,高水分含量时会受促进;同时,0.2g/(m2·a)是苔藓结皮能承受的最优氮添加量,此时苔藓结皮的光合固碳能力达到最大,年光合固碳量为对照条件的2倍。[结论]氮沉降引起的氮素增加对于干旱、半干旱区苔藓结皮的光合能力以及固碳潜力具有显著的影响。     

Impact of lower atmospheric carbon dioxide on tropical mountain ecosystems

Carbon-isotope values of bulk organic matter from high-altitude lakes on Mount Kenya and Mount Elgon, East Africa, were 10 to 14 per mil higher during glacial times than they are today. Compound-specific isotope analyses of leaf waxes and algal biomarkers show that organisms possessing CO2-concentrating mechanisms, including C4 grasses and freshwater algae, were primarily responsible for this large increase. Carbon limitation due to lower ambient CO2 partial pressures had a significant impact on the distribution of forest on the tropical mountains, in addition to climate. Hence, tree line elevation should not be used to infer palaeotemperatures.     

Expression and Localization of Vascular Endothelial Growth Factor and its Receptors in the Corpus Luteum During Oestrous Cycle in Water Buffaloes (Bubalus bubalis)

The aim of this study was to document the expression and localization of VEGF system comprising of VEGF isoforms (VEGF 120, VEGF 164 and VEGF 188) and their receptors (VEGFR1 and VEGFR2) in buffalo corpus luteum (CL) obtained from different stages of the oestrous cycle. Real‐time RT‐PCR (qPCR), Western blot and immunohistochemistry were applied to investigate mRNA expression, protein expression and localization of examined factors. In general, all the components of VEGF system (the VEGF isoforms and their receptors) were found in the water buffalo CL during the oestrous cycle. The mRNA as well as protein expression of VEGF system was highest during the early and mid‐luteal phase, which later steadily decreased (p < 0.05) after day 10 to reach the lowest level in regressed CL. As demonstrated by immunohistochemistry, VEGF protein was localized predominantly in luteal cells; however, VEGFR1 and VEGFR2 were localized in luteal cells as well as in endothelial cells. In conclusion, the dynamics of expression and localization of VEGF system in buffalo corpora lutea during the luteal phase were demonstrated in this study, indicating the possible role of VEGF system in the regulation of luteal angiogenesis and proliferation of luteal as well as endothelial cells through their non‐angiogenic function.     

Uterine Infection Influences Size and Follicular Fluid Composition of the Largest Follicle in Buffalo (Bubalus bubalis)

The effect of uterine infection on size and follicular fluid composition of the largest follicle was studied in buffalo. Reproductive tracts were collected from 102 graded Murrah buffaloes at an abattoir. Uterine infection was diagnosed by physical examination of uterine mucus, white side test and uterine cytology. Samples with pus‐containing mucus, positive reaction on white side test and/or >5% neutrophils were considered to be positive for uterine infection. Diameter of the largest follicle was measured, and follicular fluid was aspirated and assayed for nitric oxide (NO), ascorbic acid (AA), cholesterol, oestradiol (E₂) and progesterone (P₄). Infected buffaloes had smaller‐sized (p < 0.0001) largest follicles than non‐infected buffaloes. Follicular fluid collected from the largest follicle in infected buffaloes had greater (p < 0.0001) NO and P₄ concentrations coincident with lesser AA (p < 0.001), cholesterol (p < 0.0001) and E₂ (p < 0.0001) concentrations. Results indicated that uterine infection has an inhibitory effect on growth of the largest follicle in buffalo. The changes in follicular fluid composition in infected buffaloes suggest that the direct effect of uterine infection on ovarian function may be mediated through an alteration in the follicular microenvironment. Greater NO and lesser AA concentrations in the follicular fluid of infected animals are novel findings.     

Participation of Opioid Peptides in Sucking‐induced Oxytocin and Prolactin Secretions in Lactating Goats

The role of opioid peptides in the secretion of oxytocin (OT) and prolactin (PRL) induced by sucking was studied in goats. Seven goats were isolated with their kids (four singletons and three twins) in individual corrals 3–4 weeks after parturition. On day 1 of the experiment, the kids were separated from the does for 7 h and were weighed before and 15 min after being reunited with their mothers to assess the amount of milk obtained by sucking. The does were blood‐sampled 10 min before and at the end of the sucking period. On day 2, a similar protocol was followed, but naloxone was given immediately after the first blood sample. On day 3, the protocol was repeated but saline vehicle was injected instead of naloxone. On day 5, the naloxone experiment was repeated as on day 2. Milk ejection was evaluated as the difference in the weight of the kids before and after sucking for 15 min, and the maternal serum levels of OT and PRL were measured by radioimmunoassay. A significant decrease in the weight gain of the kids was obtained when the mothers were treated with naloxone on day 2. Consistently, serum levels of OT and PRL induced by sucking were significantly reduced; indicating that sucking‐induced OT secretion for milk ejection in lactating goats is facilitated by opioid peptides. In a second experiment performed in the same animals 10 days later, the administration of OT, immediately after naloxone administration, prevented the decrease in the weight gain induced by naloxone, suggesting that the effect of the opioid antagonist on milk ejection in goats is a result of a reduced OT secretion. The results of this study confirm the importance of sucking‐induced OT secretion for milk ejection in lactating goats, and indicate that OT and PRL secretion are regulated by opioid peptides in this species.