Long-term individual identification and site fidelity of white sharks, <Emphasis Type=Italic>Carcharodon carcharias</Emphasis>, off California using dorsal fins

Mark-recapture techniques can be used to estimate white shark (Carcharodon carcharias) population abundance. These frameworks are based on assumptions that marks are conserved and animals are present at the sampling location over the entire duration of the study. Though these assumptions have been validated across short-time scales for white sharks, long-term studies of population trends are dependent on these assumptions being valid across longer periods. We use 22 years of photographic data from aggregation sites in central California to support the use of dorsal fin morphology as long-term individual identifiers. We identified five individuals over 16–22 years, which support the use of dorsal fins as long-time individual identifiers, illustrate strong yearly site fidelity to coastal aggregation sites across extended time periods (decades), and provide the first empirical validation of white shark longevity >22 years. These findings support the use of fin morphology in mark-recapture frameworks for white sharks.     

Acid-base status in the sea urchins Psammechinus miliaris and Echinus esculentus (Echinodermata: Echinoidea) during emersion

The acid-base status of two sea urchins, Psammechinus miliaris (Gmelin) and Echinus esculentus (L.) during experimental emersion has been investigated. Sea urchins were collected from the Firth of Clyde between August and September 1987. The carbon dioxide capacity of the coelomic fluid of P. miliaris was greater than that of E. esculentus, although both were low and only marginally greater than that of sea water. The pH of the coelonic fluid was also low (7.05 to 7.17) and was influenced mainly by the internal partial pressure of CO₂ (P_{CO 2}). Acid-base disturbance in the coelomic fluid of both species during emersion, although minimal, was more pronounced in E. esculentus than in P. miliaris and was due primarily to an increase in the internal P_{CO 2}, although there was an increase in the concentration of L-lactate in the coelomic fluid of E. esculentus. The coelomic fluid of both species was in a state of perfectly compensated respiratory acidosis. An increase in the concentration of divalent ions (Ca²⁺ and Mg²⁺) may be related to the dissolution of the test as a source of carbonate buffer.     

Fluid bed gasification – Plasma converter process generating energy from solid waste: Experimental assessment of sulphur species

Often perceived as a Cinderella material, there is growing appreciation for solid waste as a renewable content thermal process feed. Nonetheless, research on solid waste gasification and sulphur mechanisms in particular is lacking. This paper presents results from two related experiments on a novel two stage gasification process, at demonstration scale, using a sulphur-enriched wood pellet feed.Notable SO₂ and relatively low COS levels (before gas cleaning) were interesting features of the trials, and not normally expected under reducing gasification conditions. Analysis suggests that localised oxygen rich regions within the fluid bed played a role in SO₂’s generation. The response of COS to sulphur in the feed was quite prompt, whereas SO₂ was more delayed. It is proposed that the bed material sequestered sulphur from the feed, later aiding SO₂ generation. The more reducing gas phase regions above the bed would have facilitated COS – hence its faster response. These results provide a useful insight, with further analysis on a suite of performed experiments underway, along with thermodynamic modelling.     

Contaminant Concentrations in the Atmosphere of Los Angeles County

Sampling for nitrogen and sulfur dioxides was initiated at several National Air Sampling Network stations in 1959 using a sampler developed for that purpose. In 1961 the Gas Sampling Network was expanded to its maximum of 49 stations. Sampling equipment and collecting solutions are supplied and chemical analyses performed by the network laboratories. Sampling and analysis procedures are described briefly. Average and maximum 24-hour concentrations of nitrogen dioxide and sulfur dioxide observed at 48 stations during 1961-1963 are presented.     

Schedule of Technical Sessions

Peroxyacyl nitrates are a family of compounds which result from photochemical reactions between contaminants released to the atmosphere by combustion of organic fuels. Peroxyacetyl nitrate (PAN) is the most abundant member of this family and is responsible for serious plant injury in some polluted areas. Plant injury has been recognized in at least 19 states and several foreign countries but economic loss has caused greatest concern in California. Characteristically, injury from PAN appears as glazing or bronzing of the lower leaf surface but the symptom syndrome may also include tissue collapse, chlorosis, and leaf drop. PAN inhibits activity of several enzyme systems by attacking the sulfhydryl group when enzyme extracts are fumigated in vitro, PAN may produce visible symptoms when sensitive plants are exposed for 4 hours to about 14 ppb. Other chemical members of the family are more toxic than PAN. Concentrations of 20 to 30 ppb PAN occur frequently at Riverside, Calif, and a maximum peak of 58 ppb was measured for one 2-hour period. Peaks as high as 54 ppb were reported at Salt Lake City, and 210 ppb at Los Angeles, Calif.     

A Framework for Evaluating the Effects of Human Factors on Wildlife Habitat: the Case of Giant Pandas

Abstract: To address the complex interactions between humans and wildlife habitat, we developed a conceptual framework that links human factors with forested landscapes and wildlife habitat. All the components in the framework are integrated into systems models that analyze the effects of human factors and project how wildlife habitat would change under different policy scenarios. As a case study, we applied this framework to the Wolong Nature Reserve in Sichuan Province (southwestern China), the largest home of the giant panda ( Ailuropoda melanoleuca ). We collected ecological and socioeconomic data with a combination of various methods ( field observations, aerial photographs, government documents and statistics, interviews, and household surveys) and employed geographic information systems and systems modeling to analyze and integrate the data sources. Human population size has increased by 66% and the number of households in the reserve has increased by 115% since 1975, when the reserve was established. During the same period, the quality and quantity of the giant panda habitat dramatically decreased because of increasing human activities such as fuelwood collection. Systems modeling predicted that under the status quo, human population in the reserve would continue to grow and cause more destruction of the remaining panda habitat, whereas reducing human birth rates and increasing human emigration rates would lower human population size and alleviate human impacts on the panda habitat. Furthermore, our simulations and surveys suggested that policies encouraging the emigration of young people would be more effective and feasible than relocating older people in reducing human population size and conserving giant panda habitat in the reserve.     

低浓度SO2长期暴露下菜豆的生长发育和气孔反应

本研究采用连续搅拌槽反应器系统(CSTR)对菜豆(Phaseolus vulgaris)进行低浓度SO_2长期暴露试验.结果表明,SO_2在植物可见伤害阈值以下抑制了莱豆生长,叶片气孔阻力随SO_2浓度的增加而增加.植物一旦脱离SO_2污染的环境,气孔就恢复到正常水平.切除子叶的菜豆生长明显受抑,但对SO_2敏感性和留子叶菜豆相同.