Seasonal variability of sex-ratio in<Emphasis Type="Italic"> Ips typographus</Emphasis> (L.) pheromone traps in a multivoltine population in the Southern Alps

The aim of the study was to monitor the seasonal variation in the sex-specific responses of Ips typographus to a commercial pheromone in relation to the two generations per year occurring in the Southern Alps. The study was carried out over 2 years (2000–2001). Each year, 15 Theysohn traps were baited with Pheroprax. Traps were emptied weekly and the number of beetles determined. In the same forest each year, three spruce logs were set up at the beginning of spring for natural colonisation by Ips typographus and then put in breeding boxes. All adults emerging from the logs or found in the traps were counted and a subsample sexed by genital extraction. Spring captures were always higher than summer captures (second generation). Similarly, the proportion of trapped males was always higher in spring than in summer. Except in the first and second week, the number of females was higher than males. During the first 3 weeks of monitoring, the number of trapped males dropped from above 50 to about 30%. Thereafter, the sex ratio was constant over time, about 33% males. In contrast to trap catches, about 50% of adults emerging from the breeding logs were males. The low proportion of males in traps depends both on discrimination (they avoid strong sources of male pheromone) and on differential mortality of the sex over time. As the pioneer beetles in I. typographus are males, their number is highest in the first part of the flight period when they search for suitable host trees. Such a search can be lethal for several males, decreasing the sex ratio.     

春播胡萝卜新品种天红5号的选育

天红5号以雄性不育系HLBcms005为母本,由日本引进的抗抽薹品种经过多代分离提纯后而获得的品系HLBm005为父本,采用 雄性不育三系配套育种技术选育的胡萝卜一代杂种。株高62 cm左右,10片叶,叶丛直立;肉质根根形整齐,表皮光滑,呈圆柱形, 橘红色、颜色深,髓心较细,平均根长14.47 cm,根粗4.06 cm,根质量106.92 g;胡萝卜素含量70.28 mg·kg^-1（FW）,可溶性固 形物9.11 %,品质好;大棚春播抽薹率0.26 %,较适宜春播。生长期100～105 d(天),每667 m²留苗28 000~30 000株,产量 3 200 kg左右。     

Pharmacokinetics of tobramycin in ducks and sex-related differences

The aims of the present study were to determine the disposition of tobramycin after single intravenous (IV) and intramuscular (IM) injections in ducks, and to establish any sex-related differences. Tobramycin sulfate was administered as a 2.5% water solution in a cross-over design at a dose of 5 mg/kg to 12 healthy ducks (six males and six females). Concentrations of the drug in serum were determined by a microbiological assay. The serum pharmacokinetic values for tobramycin were best represented using a one- or two-compartment open model, depending on the method of administration. Non-compartment analysis was also performed after IV administration. Tobramycin had a low degree of distribution and a relatively fast elimination. The mean volume of distribution in ducks (males and females) was higher than that reported in pigeons but lower than in chickens, with a slower rate of elimination. The IM injection resulted in a fast and complete absorption. The rate of elimination after IM administration was about twice as slow as in other avian species. Sex-related variations in tobramycin pharmacokinetics were similar to those reported for kanamycin and apramycin in hens and roosters.