Food caching in orb-web spiders (Araneae: Araneoidea)

Caching or storing surplus prey may reduce the risk of starvation during periods of food deprivation. While this behaviour occurs in a variety of birds and mammals, it is infrequent among invertebrates. However, golden orb-web spiders, Nephila edulis, incorporate a prey cache in their relatively permanent web, which they feed on during periods of food shortage. Heavier spiders significantly reduced weight loss if they were able to access a cache, but lost weight if the cache was removed. The presence or absence of stored prey had no effect on the weight loss of lighter spiders. Furthermore, N. edulis always attacked new prey, irrespective of the number of unprocessed prey in the web. In contrast, females of Argiope keyserlingi, who build a new web every day and do not cache prey, attacked fewer new prey items if some had already been caught. Thus, a necessary preadaptation to the evolution of prey caching in orb-web spiders may be a durable or permanent web, such as that constructed by Nephila.     

Practical environmental monitoring of major construction projects

Independent teams undertook environmental monitoring of particular concentrations of major construction projects forming part of Hong Kong’s U.S. $20 billion airport infrastructure programme located in dense urban areas. The team combination of environmental specialists with experienced civil engineers enabled pragmatic mitigation measures to be developed and accepted by the construction personnel with the result that potentially significant adverse impacts were averted. The authors discuss the mechanism and success of this innovative approach.     

Hydrogen storage and distribution systems

Hydrogen storage and transportation or distribution is closely linked together. Hydrogen can be distributed continuously in pipelines or batch wise by ships, trucks, railway or airplanes. All batch transportation requires a storage system but also pipelines can be used as pressure storage system. Hydrogen exhibits the highest heating value per weight of all chemical fuels. Furthermore, hydrogen is regenerative and environment friendly. There are two reasons why hydrogen is not the major fuel of toady’s energy consumption: First of all, hydrogen is just an energy carrier. And, although it is the most abundant element in the universe, it has to be produced, since on earth it only occurs in the form of water. This implies that we have to pay for this energy, which results in a difficult economic task, because since the industrialization we are used to consuming energy for free. The second difficulty with hydrogen as an energy carrier is the low critical temperature of 33 K, i.e. hydrogen is a gas at room temperature. For mobile and in many cases also for stationary applications the volumetric and gravimetric density of hydrogen in a storage system is crucial. Hydrogen can be stored by six different methods and phenomena: high pressure gas cylinders (up to 800 bar), liquid hydrogen in cryogenic tanks (at 21 K), adsorbed hydrogen on materials with a large specific surface area (at T < 100 K), absorbed on interstitial sites in a host metal (at ambient pressure and temperature), chemically bond in covalent and ionic compounds (at ambient pressure), oxidation of reactive metals e.g. Li, Na, Mg, Al, Zn with water. These metals easily react with water to the corresponding hydroxide and liberate the hydrogen from the water. Finally, the metal hydroxides can be thermally reduced to the metals in a solar furnace.     

Alteration in Rhizosphere Soil Properties of Afforested <Emphasis Type="Italic">Rhamnus lycioides</Emphasis> Seedlings in Short-Term Response to Mycorrhizal Inoculation with <Emphasis Type="Italic">Glomus intraradices</Emphasis> and Organic Amendment

The reestablisment of autochthonous plant species is an essential strategy for recovering degraded areas under semiarid conditions. A field experiment was carried out to assess the short-term effect of two reafforestation methods involving mycorrhizal inoculation and compost addition on soil quality parameters and Rhamnus lycioides seedling growth. The nutrient content (NPK) and enzymatic activities (dehydrogenase, urease, protease-BAA, acid phosphatase and β-glucosidase) increased and bulk density decreased in the rhizosphere soil with the organic amendment. Biomass C of rhizosphere soil increased by at least 240% with respect to the control soil after mycorrhizal inoculation and the combination of compost addition + mycorrhizal inoculation. Both mycorrhizal inoculation and composted organic residue addition increased R. lycioides seedling growth in the same proportion. In the short term, we conclude that the application of both reafforestation methods not only enhances the establishment of R. lycioides seedlings, but also improves soil quality.     

化学混凝-SBR法处理肉禽屠宰废水的研究

针对肉禽屠宰废水的特点，采取了先混凝后生化的处理方法。在实验中确定了最佳混凝剂和最佳工艺条件。实验结果表明，采取此方法处理肉禽屠宰废水，其各项指标可达国家规定的排放标准。