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151.
152.
The concept of sustainable development (SD) has highly been debated since it was presented 25 years ago, with ‘hard science’ approaches on one side and more process-oriented approaches on the other side. Academic teaching in SD has emerged in response to this in very different contexts, partly mirroring this academic debate. Some master’s programmes in SD take a strong science approach, while other programmes focus on the process of implementing sustainability projects, sometimes connected with forms of action research and teaching. In this article, we identify diverse views on the concept of SD as well as views on most relevant modes of teaching. We discuss core competencies required for sustainability professionals in their working practices and we organise them in three main clusters: Know, Interact and Be (KIB). The article presents the results of a worldwide survey, which addresses these visions on the concept of SD, the capabilities needed for ‘sustainable development professionals’ and the teaching approach needed. The analysis is based on the responses of 54 lecturers and 287 students active in 34 SD master’s programmes on all continents. The results of this worldwide survey are discussed. We observe in practice some gaps between preferences and practice. Looking at what both lecturers and students see as essential topics to address, some topics get relatively less attention (like the population issue). The identified core competencies (KIB) are supported and all addressed in practice, while the ‘Be’ competencies receive relatively less attention. Suggested consequences for academic teaching include a further matching of programmes with perceived needs and bridging the gap between the experienced teaching approaches in practice with such identified needs.  相似文献   
153.
Habitat structure affects intraguild predation   总被引:4,自引:0,他引:4  
Intraguild predation is thought to be ubiquitous in natural food webs. Yet, theory on intraguild predation predicts the intraguild prey to persist only under limited conditions. This gap between theory and empirical observations needs scrutiny. One reason might be that theory has focused on equilibrium dynamics and a limited set of species (usually three) that interact in well-mixed populations in unstructured habitats, and these assumptions will often not hold in natural systems. In this review, we focus on the effects of habitat structure on intraguild predation. Habitat structure could reduce encounter rates between predators and prey and could create refuges for prey. In both cases, habitat structure could reduce the strength of intraguild interactions, thereby facilitating species coexistence. A meta-analysis of studies on manipulation of habitat structure shows that intraguild prey indeed suffer less from intraguild predation in structured habitats. This was further confirmed by a meta-analysis in which studies on intraguild predation were classified according to habitat structure. Intraguild predation reduced densities of the intraguild prey significantly more in habitats with little structure than in habitats rich in structure. The effect of intraguild predation on the shared prey was negative, and not significantly affected by habitat structure. We conclude that habitat structure may increase persistence of the intraguild prey by decreasing the strength of the interaction between intraguild predator and intraguild prey.  相似文献   
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Careful consideration of the effects of the Cape orogeny on sedimentation in the Carboniferous–Jurassic Karoo Basin provides an indirect tool for accurately dating these rocks. Fossil and radiometric data, especially when combined with sedimentological and structural information, yield partly overlapping age brackets which can be used to correlate the successive tectonic pulses with specific depositional events. Application of these principles to associated basins in Gondwanaland can provide a firm foundation for more dependable stratigraphic correlation on a global scale. The exercise also suggests that a number of widely held opinions on the age of certain stratigraphic units in the Karoo Supergroup may be incorrect.  相似文献   
157.
Diapause in arthropods is a physiological state of dormancy that is generally thought to promote survival during harsh seasons and dispersal, but it may also serve to avoid predation in space and time. Here, we show that predation-related odours induce diapause in female adult spider mites. We argue that this response allows them to move into an area where they are free of enemies, yet forced to survive without food. Spider mites are specialised leaf feeders, but—in late summer—they experience severe predation on leaves. Hence, they face a dilemma: to stay on the leaf and risk being eaten or to move away from the leaf and risk death from starvation and thirst. Female two-spotted spider mites solve this dilemma by dramatically changing their physiology when exposed to predation-associated cues. This allows them to disperse away from leaves and to survive in winter refuges in the bark of trees or in the soil. We conclude that the mere presence of predation-associated cues causes some herbivorous mites to seek refuge, thereby retarding the growth rate of the population as a whole: a trait-mediated indirect effect that may have consequences for the stability of predator–prey systems and for ecosystem structure.  相似文献   
158.
Goal, Scope and Background Atmospheric sampling (gas and particles) of 5 phenols (phenol, m-cresol, p-cresol, o-cresol, pentachlorophenol) and 15 nitrophenols (3-methyl-2-nitrophenol, 3-nitrophenol, 4-methyl-2-nitrophenol, 5-methyl-2-nitrophenol, 2-methyl-3nitrophenol, 3-methyl-4-nitrophenol, 2,6-dinitrophenol, bromoxynil, 2,5-dinitrophenol, 2,6-dinitro-p-cresol, 2,4-dinitrophenol, ioxynil, DNOC, 3,4-dinitrophenol, dinoseb) on XAD-2 resin (20 gr) and glass fibre filters, respectively, were performed in 2002 by using 'Digitel DA80' high volume samplers. These measurements were undertaken in order to show spatial and geographical variations of concentrations and the role of traffic in the emissions of these compounds to the atmosphere. Methods Sampling were performed in Strasbourg (eastern France), in its vicinity (Schiltigheim) and in Erstein. Sites were chosen to be representative of urban (Strasbourg), suburban (Schiltigheim) and rural (Erstein) conditions. Field campaigns were undertaken simultaneously in urban and suburban sites during all the seasons during 4 hours at a flow rate of 60 m3.h-1, which gives a total of 240 m3 of air per sample. Period of sampling varied between 06h00 to 10h00, 11h00 to 15h00 and 18h00 to 22h00 in order to evaluate a variation of concentration during automobile traffic between urban, suburban and rural areas. Gas and particle samples were separately Soxhlet extracted for 12 h with a mixture of CH2Cl2 / n-hexane (50:50 v/v), concentrated to about 1 mL with a rotary evaporated and finally dried under nitrogen. Dry extracts were dissolved in 1 mL of CH3CN. Before analysis, extracts were sylilated by using MTBSTFA. Analysis was performed by GC/MSD in the SIM mode. Results and Discussion Partitioning of phenolic compounds between gas and particle phases seems to be mainly correlated with vapour pressure. Among phenolic compounds analysed, phenol, p-cresol, pentachlorophenol and 2.4-dinitrophenol were detected in all samples and emissions from traffic seems to be the major source for the presence of these compounds to the atmosphere. No increase of concentrations in autumn tend to confirm this hypothesis since, with the use of domestic heating in colder months, increases of PAHs concentrations were observed and these compounds are known to be emitted by all combustion processes. Pentachlorophenol is a special case since this molecule is only used as wood preservative. Its presence in all atmospheric samples, whatever the locations and the period of time is the consequence of its persistence. Conclusions and Perspectives These measurements demonstrate that phenols and nitrophenols are emitted to the atmosphere and further measurements, in order to confirm their sources, their behaviour and their potential impact to the air quality and to human health should be undertaken especially since the literature collected is relatively old. Concentrations of pentachlorophenol measured are very low and, due to its toxicity, further investigations should be undertaken. - * The basis of this peer-reviewed paper is a presentation at the 9th FECS Conference on 'Chemistry and Environment', 29 August to 1 September 2004, Bordeaux, France.  相似文献   
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