Electricity in the marketplace: Reconfiguring the consumption of essential resources

This paper critically examines how privatisation and liberalisation of electricity provision is reconstructing energy consumption practices. The paper discusses the commercial restructuring of the electricity industry in the UK over the last four years, illustrating how a reconfiguration of production and consumption interests is transforming the utility marketplace: differentiating the value of resource units, distinguishing between infrastructure suppliers and stratifying utility customers. This process is shown to be resulting in differential forms of service provision as utility companies actively engage with more lucrative customers, presenting opportunities for environmental innovation, while disengaging from unprofitable customers and heightening social polarisation.     

Vision-independent odometry in the ant Cataglyphis cursor

In contrast to flying insects, in which distance estimation is visually mediated, self-induced image motion and use of familiar landmarks are known to play a minor role in ants. Here we show that strictly diurnal Cataglyphis cursor ants can gauge with accuracy the distance they have travelled even in complete darkness in the absence of any other cues, i.e. chemical or protocounting information. Thus, an ants odometer is a vision-independent system based on proprioceptive cues, implicating some form of step counting, which remain to be elucidated.     

Nest excavation in ants: group size effects on the size and structure of tunneling networks

Collective digging activity was studied in the ant Messor sancta Forel in laboratory conditions and with a two dimensional set-up. We analyzed the digging dynamics and topology of tunneling networks excavated by groups of workers ranging from 50 to 200 individuals over 3 days. In all conditions, the dynamics of excavated sand volume were clearly non-linear. Excavation began with an exponential growth and after 3 days reached a saturation phase in which activity was almost totally stopped. The final volume of sand excavated was positively correlated with the number of workers. At the end of the experiments, the two-dimensional tunneling networks were mapped onto planar graphs where the vertices represent small chambers or intersections between tunnels and the edges represent tunnels. We found that all the networks belonged to a same topological family and exhibited several striking invariants such as the distribution of vertex degree that follows a power law. When increasing the number of ants, some changes occurred in the network structure, mainly an increase in the number of edges and vertices, and the progressive emergence of enlarged and highly connected vertices.     

Reproductive cycle and seasonal feeding activity of the neogastropod Buccinum undatum

The whelk Buccinum undatum L. in the northern Gulf of St. Lawrence has a distinct annual reproductive cycle. The ovary and pallial oviduct of the female, and the seminal vesicle of the male, show parallel development, whereas the testis has an inverse cycle. Thus, at the end of winter when the ovary, pallial oviduct and seminal vesicle reach maximal size, the testis is small and undeveloped, whereas the reverse situation occurs in summer. This is the first report of a totally inverse relationship between the ovary and testis for a marine invertebrate. This unusual pattern is due to the long-term storage of sperm in the seminal vesicle of the male prior to copulation. There is no resting period at the end of oogenesis, but rather renewed ovarian development starts shortly after gamete release. By contrast, in the testis after transfer of sperm to the seminal vesicle at the end of spermatogenesis, there is a distinct period of phagocytosis. Mating begins in mid-May, reaches a peak during June and terminates prior to July. Egg laying begins in late May, reaches a peak in mid-June to mid-July and can continue until late August. Examination of the incidence of individuals with food in their stomachs showed that feeding activity is maximal in late autumn through to early spring and decreases sharply coincident with the onset of breeding in late May.     

Baboons adjust secondary sex ratio in response to predictors of sex-specific offspring survival

Summary Most theories of sex ratio adjustment assume that parents will adjust the sex ratio of births (secondary sex ratio) in a manner that maximizes offspring reproductive success (as long as this does not jeopardize parental reproductive success). Survival to maturity is typically the largest component of variance in offspring reproductive success. This should make environmental predictors of sex-specific offspring survival strong predictors of secondary sex ratio adjustment. We tested this survivorship maximization hypothesis for secondary sex ratio adjustment using data from a 17-year demographic study of 315 yellow baboon infants at Mikumi National Park, Tanzania. Sex differences were found in the degree to which several social and ecological conditions affected infant survival to 1 year. Female, but not male, infant survival was inversely correlated with birth order and the proportion of infant females in their birth cohort. Male, but not female, infant survival was inversely correlated with the amount of rainfall early in the year (January) and the proportion of infant males in their birth cohort; male survival also was positively correlated with maternal dominance rank. The consistency and timing of these effects across years suggested that such information was, in fact, available to females around the time of conception. Most importantly, social and ecological conditions that predicted improved survivorship of a given sex also were positively correlated with production of that sex. Early births were female-biased; and low January rainfall was correlated with a male-biased sex ratio, becoming increasingly female-biased as January rainfall increased. However, no sex ratio effects were correlated with maternal rank. Data supported the hypothesis that females adjusted secondary sex ratio in a manner that maximized sex-specific infant survival. This hypothesis also offered a plausible explanation for some of the contradictory data that have arisen from studies of maternal rank effects on sex ratio both within and between species.Correspondence to: S. K. Wasser     

Amylo-1,6-glucosidase activity in cultured cells: A deficiency in type III glycogenosis with prenatal studies

Deficiency of amylo-1,6–glucosidase activity was expressed in parallel in liver and skin fibroblasts from a patient with type III glycogenosis. In crude extracts of control liver and muscle, amylo-1, 6–glucosidase (M.W. 164000) was identified by immunoprecipitation; no cross-reacting material was found in the patient's liver. Assay of amylo-1,6–glucosidase activity in cultured skin fibroblasts from the affected family revealed less than 10 per cent of control value in mutant homozygous cells whereas in cells from the parents, activity was reduced to 40–60 per cent of the control value. Activity in cultured amniotic fluid cells was similar to that of control fibroblasts. In cultured amniotic fluid cells obtained during the mother's subsequent pregnancy, the normal amylo–1,6–glucosidase activity measured, predicted correctly the outcome of this pregnancy prior to the 20th week of gestation.     

Differences in the electroantennal responses of apple- and hawthorn-infesting races of Rhagoletis pomonella to host fruit volatile compounds

Summary. Domestic apple (Malus pumila)- and hawthorn (Crataegus sp.)-infesting races of Rhagoletis pomonella, Walsh (Diptera: Tephritidae) provide an excellent model to examine the role that host plant specificity plays during sympatric speciation (i.e., divergence in the absence of geographic isolation). Previous work has shown that these races differ in their propensities to accept apple and hawthorn fruits in behavioral choice assays, and that this discrimination translates into "host fidelity" in the field (i.e., apple flies tend to mate on and oviposit into apples and hawthorn flies on hawthorns). ?We present the results of a study examining possible physiological factors contributing to host choice differences in R. pomonella. We tested whether apple and hawthorn flies differ in their electroantennogram (EAG) responses to biologically relevant volatile compounds emitted from apples and hawthorns. Significant differences were found in the relative EAG responses of apple and hawthorn flies to host fruit compounds at five of six paired study sites across the eastern United States. The geographic pattern of EAG variation was complex, however, with local populations of apple and hawthorn flies tending to be more similar to one another than to flies of the same race at distant sites. This pattern was largely due to EAG responses for several compounds showing longitudinal or latitudinal clines, the latitudinal clines being similar to those observed for allozyme loci in the host races. We also found evidence for sex-related differences, as males tended to have higher mean EAG responses to compounds than females. Host-associated differences were therefore nested within geographic and sex-related differentiation in R. pomonella.?Further behavioral studies are needed to distinguish whether the EAG differences are responsible for, as opposed to being a consequence of, host-plant fidelity and adaptation. Crosses are also required to establish a genetic basis for the EAG responses, although we did find significant correlations between EAG scores for several compounds and the allozymes NADH-Diaphorase-2 and Hydroxyacid dehydrogenase at one of the study sites. Questions therefore remain concerning the evolutionary significance of the EAG response differences between apple and hawthorn fly races. Nevertheless, these differences raise the possibility that antennal responses to fruit-related volatile compounds contribute to host plant discrimination in R. pomonella. Regardless, the EAG responses represent another set of traits, in addition to diapause/eclosion time phenotypes and allozyme frequencies, differing between apple and hawthorn host races of R. pomonella. Received 17 March 1998; accepted 21 September 1989.     

Potential responses of terrestrial biodiversity in Southern Africa to anthropogenic climate change

Key studies supported by species-level data collection have provided early indications of the potential implications of unmitigated change for the ecosystems and biodiversity of southern Africa. These suggest a significant threat to biodiversity, both from changing bioclimatic suitability and changing atmospheric CO₂ level that seems to affect the competitive balance between woody and herbaceous plants in the dominant savanna biome of this region. Modeling efforts suggest significant implications of unmitigated climate change for this region, but assumptions underpinning methods such as bioclimatic modeling must be recognized, some of which might lead to over estimates of the rate and extent of the potential impacts. General trends and level of coincidence between various types of studies do support a high degree of concern for a substantial portion of southern African biodiversity under unmitigated climate-change scenarios. The most significant changes in ecosystem structure (both increases and decreases in woody plant cover), and associated faunal diversity changes, are projected in the dominant savanna vegetation type in this region, while the most significant biodiversity loss is projected for the winter rainfall region. Follow-up work to detect early signs of climate change identify regions of high- and low-potential impacts, and experimental work to test some important hypotheses relating to the future evolution of climate-change impacts across the region are very few and urgently required.     

Ensuring effectiveness of information to influence household behaviour

The behaviour of household members has a significant impact on the resulting energy consumption of a household. Studies show that within the same buildings with the same installations, energy consumption can be reduced by an average of 37% by a more economical behaviour. There exists therefore, a large potential to reduce the demand by influencing behaviour.The question remains how this potential can be addressed. VITO conducted, in collaboration with the Catholic University of Louvain-la-Neuve, the SEREC-project. This project investigated the socio-economic factors influencing residential energy consumption; furthermore, in the larger framework different tools have been developed. Several were tested and evaluated in a number of dwellings in this research. They address both energy consumption for heating as well as electricity consumption. The tools are completely different, but all were designed to help make householders aware of their energy-related behaviour and to provide recommendations on energy saving measures. For each case, potential changes in habits were followed-up. The observed range is quite large, as full scale audits of every dwelling were performed as general comparisons of annual consumption were made.To gain more insight into the effectiveness of the tools, several families participated in in-depth sociological interviews. The overall results show the strengths and weaknesses of the different tools. More generally, the results reveal some of the key properties of recommendations that are necessary to ensure effectiveness for behavioural change.     

Views of the City: multiple pathways to sustainable transport futures

In this paper we look behind the notion of sustainable transport and highlight the tensions and contradictions between the different ways of achieving this. The paper examines transportation plans for a major UK city and describes how these develop the idea and practice of sustainable transport and demand management along three quite distinct trajectories. By focusing on both the technological and the institutional dimensions of three different routes to sustainable transport, the analysis explicates the different ways in which the urban transport problem is framed, the different socio-technical logics of demand management embodied in the plans and the differing ways in which institutional relationships are (re)constituted. A key finding is that technological and institutional innovations are inversely related so that radical technological innovation often serves to reinforce existing social relations of power and exclusion. The conclusion drawn is that the choice is not just between a sustainable and an unsustainable transport future, but also between different forms of sustainability.