Changes in Metallothionein Levels in Freshwater Mussels Exposed to Urban Wastewaters: Effects from Exposure to Heavy Metals?

Municipal effluents are complex mixtures of compounds such as heavy metals, aromatic and aliphatic hydrocarbons, and micro-organisms and are released in aquatic ecosystems. The purpose of this study was to verify whether changes in metallothioneins (MT) were associated with the accumulation of labile metals in tissue of freshwater mussels exposed to the dispersion plume of a major municipal effluent. Mussels were placed in experimental cages deployed at sites 1.5 km upstream, 8 km downstream and 12 km downstream of the outfall of a major, primary-treated municipal effluent in the St. Lawrence River (Québec, Canada). Mussels were analysed for MT and labile zinc levels in their gonads, gills and digestive glands. Lipogenic enzyme (isocitrate and glucose-6-phosphate dehydrogenase) and arachidonic acid cyclooxygenase (COX) activities were also measured in gonad and gill tissues. Although MT was induced in all the tissues examined, the results showed that labile zinc levels were significantly reduced in gill and gonad tissues, with an increase observed only at the 12 km downstream site in the digestive gland. COX activity was readily induced in gills and gonads. Glucose-6-phosphate dehydrogenase activity was reduced at both downstream sites, but isocitrate dehydrogenase activity was significantly induced at the farthest (12 km) site. Analysis of covariance revealed that MT levels in gills were more influenced by COX activity than with distance in the dispersion plume and was negatively correlated with labile zinc levels. In conclusion, MT induction was inversely related to the levels of labile zinc but positively so with the inflammation biomarker COX. Hence, the induction of MT in mussels exposed to the municipal effluent of a large city appears to be associated with either inflammatory processes or as compensation for the loss of labile essential metals. We propose that the simple and complimentary parameters of labile zinc and COX evaluations be used to link MT induction with divalent heavy metal exposure in environmental studies dealing with various type of contaminants in such complex contaminant mixture effluents

Positive Feedback, Memory and the Predictability of Earthquakes

We review the "critical point" concept for large earthquakes and enlarge it in the framework of so-called "finite-time singularities". The singular behavior associated with accelerated seismic release is shown to result from a positive feedback of the seismic activity on its release rate. The most important mechanisms for such positive feedback are presented. We introduce and solve analytically a novel simple model of geometrical positive feedback in which the stress shadow cast by the last large earthquake is progressively fragmented by the increasing tectonic stress. Finally, we present a somewhat speculative figure that tends to support a mechanism based on the decay of stress shadows. This figure suggests that a large earthquake in Southern California of size similar to the 1812 great event is maturing.Comment: PostScript document of 18 pages + 2 eps figure

Origin and thermal evolution of Mars

The thermal evolution of Mars is governed by subsolidus mantle convection beneath a thick lithosphere. Models of the interior evolution are developed by parameterizing mantle convective heat transport in terms of mantle viscosity, the superadiabatic temperature rise across the mantle, and mantle heat production. Geological, geophysical, and geochemical observations of the compositon and structure of the interior and of the timing of major events in Martian evolution are used to constrain the model computations. Such evolutionary events include global differentiation, atmospheric outgassing, and the formation of the hemispherical dichotomy and Tharsis. Numerical calculations of fully three-dimensional, spherical convection in a shell the size of the Martian mantle are performed to explore plausible patterns of Martian mantel convection and to relate convective features, such as plumes, to surface features, such as Tharsis. The results from the model calculations are presented

Energy Literacy in Canada

Energy plays an important role in everyday activities, whether at a personal, institutional, corporate or social level.  In this context, an informed or literate public is critical for the longterm conservation, management, pricing and use of increasingly scarce energy resources.  A series of surveys were used to probe the literacy of Canadians with regard to energy issues ranging from relative ranking and importance of energy compared to other national issues, preference for various fuel types and willingness to pay for offsetting environmental impacts from energy generation. In addition, they were asked how Canada’s government should prioritize national energy independence over trade, even if ultimately reducing imports might impact national economic health. The survey revealed that Canadians have a good general knowledge of energy use and relative cost but lack detailed knowledge about sources of energy fuels, as well as sources and linkages with environmental impacts. However, an overwhelming majority of respondents indicated they were concerned about environmental issues; most seemed to direct that concern towards fuels such as coal and nuclear power where support was low compared to a relatively unconcerned view about the often substantial environmental effects of hydro dams or wind farms. Canadians say they have been willing to make adjustments to their own energy-consumption habits, to save money and conserve energy. Further, respondents  generally expressed a willingness to pay a surcharge on monthly utility bills, if it would help mitigate the environmental impact of energy generation. There were limits to this view. Support for extra charges falls off rapidly as the costs go up; drivers showed themselves highly resistant to switching their commute to transit, even despite rising gas prices; and respondents were less enthusiastic to the idea of installing home solar panels or switching to electric cars, even when offered a subsidy to do so. In spite of some limitations regarding overall energy literacy, Canadians are also highly skeptical about the information they do get from virtually every stakeholder in the energy arena. In terms of trust and confidence, overall, respondents said they were more willing to listen to academics and economic experts; only a small majority was willing to fully trust those information sources at even low levels. In this serious topic area, respondents indicated they could not trust the credibility of environmental groups, and considered the oil and gas industry and governments by far the least trustworthy sources of information. Finally, in terms of future policy development, most cite the importance of Canada’s energytrading relationship with the United States, but believe it is too dominant, and should diminish, with more effort focused on opening up new export markets elsewhere

Aboriginal-Canadians and Energy Literacy: A Survey of Opinions and Thoughts on Energy

In Canada, the energy and resource industry, its investments, employment and products have an effect on every citizen and every cultural group. And yet, the public debate over energy projects in Canada is increasingly divisive. Aboriginal-Canadians are an important part of the debate over land use and energy development, and it is essential to understand the attitudes towards and knowledge of energy in this unique group. This survey of Aboriginal-Canadians from across the country reveals that their knowledge and opinions about Canada’s energy system are similar to that of Canadians polled in previous surveys of the general population and of business and policy leaders. However, in a few key areas, the opinions of AboriginalCanadians diverge from those of other poll respondents. Aboriginal-Canadians place less trust in business, industry groups and the government as reliable sources of information about energy issues. Thirty-four per cent of Aboriginal-Canadians put absolutely no trust in information from oil and gas companies, compared to 26 per cent of the general public, and 24 per cent of Aboriginal-Canadians put no trust in information from the federal government, compared to only 15 per cent of the general public. Additionally, Aboriginal-Canadians tend to place a much higher emphasis on environmental preservation over economic concerns: they say they are “very concerned” about the environmental impacts of energy production at a rate that is 14 percentage points higher than the general public. Land and land access are important issues for the Aboriginal-Canadians surveyed. They reluctantly support oil and gas pipelines near their communities, with only 38 per cent in favour. When project development delivers additional funding for educational and social programs in their community, support shifts to a slight majority (51 per cent). This survey highlights the need for simultaneously extending efforts to improve the energy literacy of this important demographic and cultural group, while incorporating their opinions, beliefs and land ethics into long-term energy development strategies. Overall, this group understands many of the overarching issues facing energy development that impacts them, yet reinforces the gap in public knowledge revealed in the previous surveys. Developing Canadian energy will require addressing Aboriginal-Canadian concerns, including lack of trust and the environmental impacts of energy projects

The temperature dependence of the isothermal bulk modulus at 1 bar pressure

It is well established that the product of the volume coefficient of thermal expansion and the bulk modulus is nearly constant at temperatures higher than the Debye temperature. Using this approximation allows predicting the values of the bulk modulus. The derived analytical solution for the temperature dependence of the isothermal bulk modulus has been applied to ten substances. The good correlations to the experiments indicate that the expression may be useful for substances for which bulk modulus data are lacking

Using the seismology of non-magnetic chemically peculiar stars as a probe of dynamical processes in stellar interiors

Chemical composition is a good tracer of hydrodynamical processes that occur in stars as they often lead to mixing and particle transport. By comparing abundances predicted by models and those observed in stars we can infer some constraints on those mixing processes. As pulsations in stars are often very sensitive to chemical composition, we can use asteroseismology to probe the internal chemical composition of stars where no direct observations are possible. In this paper I focus on main sequence stars Am, lambda bootis, and HgMn stars and discuss what we can learn of mixing processes in those stars from seismology.Comment: 10 pages,6 figures. accepted in Journal of astrophysics and astronomy. proceedings of aries conferemce on asteroseismology. december 200

Snow metamorphism: a fractal approach

Snow is a porous disordered medium consisting of air and three water phases: ice, vapour and liquid. The ice phase consists of an assemblage of grains, ice matrix, initially arranged over a random load bearing skeleton. The quantitative relationship between density and morphological characteristics of different snow microstructures is still an open issue. In this work, a three-dimensional fractal description of density corresponding to different snow microstructure is put forward. First, snow density is simulated in terms of a generalized Menger sponge model. Then, a fully three-dimensional compact stochastic fractal model is adopted. The latter approach yields a quantitative map of the randomness of the snow texture, which is described as a three-dimensional fractional Brownian field with the Hurst exponent H varying as continuous parameter. The Hurst exponent is found to be strongly dependent on snow morphology and density. The approach might be applied to all those cases where the morphological evolution of snow cover or ice sheets should be conveniently described at a quantitative level

Quantum spectrum as a time series : Fluctuation measures

The fluctuations in the quantum spectrum could be treated like a time series. In this framework, we explore the statistical self-similarity in the quantum spectrum using the detrended fluctuation analysis (DFA) and random matrix theory (RMT). We calculate the Hausdorff measure for the spectra of atoms and Gaussian ensembles and study their self-affine properties. We show that DFA is equivalent to $\Delta_3$ statistics of RMT, unifying two different approaches.We exploit this connection to obtain theoretical estimates for the Hausdorff measure.Comment: 4+ pages. 2 figure