The trail pheromone of the ant <Emphasis Type="Italic">Crematogaster castanea</Emphasis>

Summary. The major component of the trail pheromone of the myrmicine ant Crematogaster castanea has been identified as (R)-2-dodecanol from the tibial glands of the hind legs. The substance gave activity comparable to the contents of 8 tibial glands at a concentration of 1 pg per 32 cm trail.     

Model description of an alternately operated wastewater treatment plant--evaluation of the applicability of SimpleTreat

Alternately operated wastewater treatment plants (WWTPs) are fundamentally different compared to conventional activated sludge WWTPs with respect to flow patterns and aeration in the biological reactors. Several model applications exist for conventional WWTPs, e.g. SimpleTreat, and in this study the effect of substituting a complex discontinuous operation, involving alternating degradation and flow conditions between two reactors, with one single bioreactor with continuos flow (SimpleTreat) has been investigated by setting up two models representing the respective operation schemes. The discontinuous operation induces fluctuations in the outlet concentrations that are not modelled with the single bioreactor model, however, the fluctuations and the associated uncertainties were found to be insignificant compared to the influence of the input parameter uncertainties on the model results. An empirical relationship between an aggregate pseudo-1st order degradation rate for the single bioreactor model and realistic aerobic and anoxic 1st order degradation rates, respectively, has been established. When using this aggregate degradation rate in the single bioreactor model an outlet concentration can be calculated that deviates no more than 2% from the mean outlet concentration from the alternating operation model. For substances with aerobic half-lives longer than approximately 2 h, which is valid for many chemical substances, the aggregate 1st order degradation rate can be set equal to the aerobic 1st order degradation rate.     

城市交通环境对行道树叶片表皮结构影响的研究

以珠江三角洲常见的 8种受到交通环境影响的城市行道树及其对照树作为研究材料 ,对其叶片的上下表皮结构进行了研究。结果表明 ,交通环境引起城市行道树叶片表皮结构如气孔数、气孔口等发生变化 ,但不同的树种的叶片表皮结构对交通环境的响应不同。     

粉锻件预制坯的设计

讨论了粉锻件预制坯的设计内容预制坯密度的选择、形状和尺寸的设计 ,讨论了粉锻件预制坯的分类简单形状预制坯和近似形状预制坯 ,讨论直齿轮、伞齿轮、法兰件和长轴类粉锻件预制坯的设计     

Biodiversity conservation incentive programs for privately owned forests

In many countries, a large proportion of forest biodiversity exists on private land. Legal restrictions are often inadequate to prevent loss of habitat and encourage forest owners to manage areas for biodiversity, especially when these management actions require time, money, and other resources. Environmental programs encouraging these actions through economic incentives can be used instead of additional legal restrictions, although to be efficient and successful, an incentive program must be thoughtfully developed and its conservation goals must be clear. In addition to being economically efficient, programs must be acceptable to landowners and ecologically appropriate, especially with respect to the case-specific objectives and the ecosystems in question. We introduce a sample of voluntary incentive programs for private forests in Europe and North America. We briefly describe the economic, social, and ecological characteristics of the programs and the forests they aim to conserve, and evaluate the success of these programs with respect to their explicitly stated goals and the ecological status of the forests in that country or state. Important factors contributing to program success include an allowance for some economic productivity in enrolled forests, a long period since time of program inception, and little interference from other incentive programs.     

Determination of cytotoxic,genotoxic, and oxidative damage from deltamethrin on primary hepatocyte culture of Lake Van fish,Alburnus tarichi

ABSTRACT

Deltamethrin is a widely used pyrethroits worldwide. Although the chemical is used to combat insects, it has effects on other non-target organisms. Deltamethrin is extensively used in agriculture, animal husbandry, and domestic areas in the Lake Van basin. The aim of this study was to determine the cytotoxic, genotoxic, and oxidative damage from deltamethrin on the primary hepatocyte culture of Lake Van fish (Alburnus tarichi). In this study, the toxic effects of different concentrations (0.01, 0.1, 1, and 10?µM) of deltamethrin in the primary hepatocyte culture of Lake Van fish were investigated via liver enzymes aspartase aminotransferase (AST) and alanine aminotransferase (ALT), and the total antioxidant status (TAS), total oxidant status (TOS), lipid peroxidation (MDA), and DNA damage (8-OHdG).

Deltamethrin caused an increase in the AST and ALT levels dependent on the dosage and time. The TAS and TOS levels increased at the end of 24?h and there was no difference at the end of 48?h. Deltamethrin did not affect the MDA level, but increased the 8-OHdG (P?<?0.05). In conclusion, it can be said that high doses of deltamethrin (1 and 10?µM) have a toxic effect on the primary hepatocyte culture of Lake Van fish.     

Recurrent and changing seasonal patterns in phytoplankton of the westernmost inlet of the Dutch Wadden Sea from 1969 to 1985

Data for phytoplankton composition and abundance in the Marsdiep are presented for the period from 1969 to 1985 inclusive. Only a few species dominated the phytoplankton. A recurrent pattern was observed in the seasonal succession: in winter, total cell numbers were invariably low, but freshwater algae, sluiced into the Wadden Sea from IJssel Lake, showed highest densities in winter. A diatom spring peak was observed around mid-April, followed by a Phaeocystis pouchetii peak about three weeks later. Later in summer usually two more diatom peaks followed by non-diatom peaks were present. The exact timing of the spring peak varied from year to year, with the extremes being late March and early May. A relatively late spring peak usually coincided with a relatively high turbidity in the preceding winter. An increase in total cell numbers was found over the 17-year observation period. Diatoms decreased from 1969 to 1974 but have increased since then, reaching values above those of 1969 during recent years. Flagellates showed a consistent increase over the entire observation period.