Convection and heat transfer in layered sloping warm-water\ud aquifers

What convective flow is induced if a geologically-tratified groundwater aquifer is subject to a vertical temperature gradient? How strong is the flow? What is the nett heat transfer? Is the flow stable? How does the convection affect the subsequent species distribution if a pollutant finds its way into the aquifer? This paper begins to address such questions. Quantitative models for buoyancy-driven fluid flow in long, sloping warm-water aquifers with both smoothly- and discretely-layered structures are formulated. The steady-state profiles are calculated for the temperature and for the fluid specific volume flux (Darcy velocity) parallel to the boundaries in a sloping system subjected to a perpendicular temperature gradient, at low Rayleigh numbers. The conducted and advected heat fluxes are compared and it is shown that the system acts somewhat like a heat pipe. The maximum possible ratio of naturally advected-to-conducted heat transfer is determined, together with the corresponding permeability and thermal conductivity profiles

Reducing coal subsidies and trade barriers: their contribution to greenhouse gas abatement

Reprinted in International Trade and the Environment, edited by J. Dean for the International Library of Environmental Economics and Policy, Aldershot: Ashgate, 2002 Published online by Cambridge University Press 03 Nov 2000International negotiations for an agreement to reduce the emission of greenhouse gases have not produced cost-effective policies for reducing emissions, not least because they are unlikely to prevent ‘leakage’ through a re-location of carbon-intensive activities to poorer countries. An alternative or supplementary approach that is more likely to achieve at least some emission reductions, and at the same time generate national and global economic benefits rather than costs, involves lowering coal subsidies and trade barriers. Past coal policies have encouraged excessive production of coal in a number of industrial countries and excessive coal consumption in numerous developing and transition economies. This paper documents those distortions and outlines the circumstances under which their reform (currently under way in some countries) could both improve the economy and lower greenhouse gas emissions globally. It then quantifies the effects on economic activity as well as global carbon emissions, using the G-Cubed multi-country general equilibrium model of the world economy. Both the gains in economic efficiency and the reductions in carbon dioxide emissions that could result from such reforms are found to be substantial—a ‘no regrets’ outcome or win–win Pareto improvement for the economy and the environment.Kym Anderson and Warwick J. McKibbi

Effects of the current financial and economic crisis on the rural landscape as well as the agri-food sector in Europe and Central Asia

This paper reviews the expected effects of the current financial crisis and subsequent recession on the rural landscape, in particular the agri-food sector in Europe and Central Asia (ECA) on the basis of the structure of the rural economy and of different organisations and institutions. Empirical evidence suggests that the crisis has hit the ECA region the hardest. Agriculture contributes about 9% to gross domestic product (GDP) for the ECA region as a whole with 16% of the population being employed in the agricultural sector. As far as the impact of the financial crisis on the agri-food sector is concerned, there are a few interconnected issues: (1) reduction in income elastic food demand and commodity price decline, (2) loss of employment and earnings of rural people working in urban centres, implying also costly labour reallocation, (3) rising rural poverty originating mainly from lack of opportunities in the non-farm sector and a sizable decline of international remittances, (4) tightening of agricultural credit markets, and the (5) collapse of sectoral government support programs and social safety-net measures in many countries. The paper reveals how the crisis hit farming and broader agri-business differently in general and in the ECA sub-regions

The Asian Financial Crisis: Effects on U.S. Agriculture

Abstract This paper analyzes the likely effects of the recent Asian financial crisis on the U.S. economy and agriculture. It uses a multi-country, multi-sector dynamic intertemporal general equilibrium model, with endogenously modeled financial markets (G-cubed agriculture). Two simulations are done: one in which the crisis is confined to Korea and Southeast Asia, where the problem was most acute as of the fall of 1998, and another in which the crisis is assumed to deepen in Japan, China, and Taiwan to the same extent as it already has in Korea and Southeast Asia. The results show that the Asian financial crisis has a number of offsetting effects on U.S. agriculture. U.S. exports of agricultural and food products fall in response to declining demand in the affected countries in Asia and the appreciation of the U.S. dollar. U.S. agricultural and food exports are estimated to decline three times as much when Japan, China, and Taiwan become embroiled in the crisis than when it is confined to Korea and Southeast Asia. On the other hand, adjustments in global capital and energy markets in both scenarios reduce capital costs and input prices faced by U.S. farmers and, more broadly, stimulate domestic U.S. economic activity in the short run, particularly in interest-sensitive and energy-intensive sectors. Thus the shortrun effects of the Asian crisis on U.S. agriculture are ambiguous. Sectors relying more on domestic demand, such as livestock products and processed food, expand output, while export-oriented sectors such as food grains are negatively affected

Demographic and health factors associated with pandemic anxiety in the context of COVID-19

Objectives. The mental health consequences of COVID-19 are predicted to have a disproportionate impact on certain groups. We aimed to develop a brief measure, the Pandemic Anxiety Scale, to capture the specific aspects of the pandemic that are provoking anxiety, and explore how these vary by health and demographic factors. Design. Data were from a convenience sample of parents (N = 4,793) and adolescents (N = 698) recruited in the first 6 weeks of lockdown. Methods. Factor analytic and IRT methods were used to validate the new measure in both parent and adolescent samples. Associations between scores on the new measure and age, gender, household income, and physical health status were explored using structural equation modelling (SEM). Results. Two factors were identified in both samples: disease anxiety (e.g., catching, transmitting the virus) and consequence anxiety (e.g., impact on economic prospects); and unique associations with health and demographic factors were observed. Conclusions. Anxieties due to the COVID-19 are multifaceted, and the PAS is a short, reliable, and valid measure of these concerns. These anxieties are differentially associated with demographic, social, and health factors, which should be considered when developing strategies to mitigate the mental health impact of the pandemic

Reconstructing Climate Policy: How Best to Engage China and Other Developing Countries?

Duke University organized the International Conference on Reconstructing Climate Policy: Moving Beyond the Kyoto Impasse, May 2003. The organizer invited me to specifically address the following two issues at the conference: 1) Whether is the proposal for joint accession by the U.S. and China in the interest of China?, and 2) Even if participating a global cap-and-trade regime is so beneficial to China as many economic studies suggest, why has China consistently refused in international negotiations even to discuss its participation in it?. In this paper, we look at the first issue from the following perspectives: a) how does China value importance of maintaining unity of the Group of 77?; b) what lessons has China learned from bilateral negotiations with the U.S. to work out the terms for China to get accession to the WTO?; c) what is the legitimacy of the U.S. insistence that it re-joins the Kyoto Protocol only if major developing countries join?; d) what are implications of the U.S. strikingly reversed position on the commitments of developing countries in New Delhi for initiating discussions on joint accession by the U.S. and China?; and e) how would joint accession by the U.S. and China be perceived?. We then address the second issue from the following perspectives: a) from the point of view of fairness, how do developing countries including China and India perceive emissions caps in the first place?; b) why have China and India been sceptical to international emissions trading?; c) how is an inflow of CDM investment in China perceived politically in comparison with the exports of emissions permits to the U.S.?; d) what are the implications of “lock in” to emissions cap, in particular no rules and principles for setting emissions targets for the commitment periods subsequent to Kyoto?; e) how to address the complex undertaking of setting emissions caps for developing countries, which must be linked to future, unobserved levels in comparison with the historically observed levels for industrialized countries?. Finally, the paper touches on the likely path forward

Snake mortality and cover board effectiveness along exclusion fencing in British Columbia, Canada

We report on snake mortalities along exclusion fencing in southern British Columbia, showing Western Yellow-bellied Racer (Coluber constrictor mormon) deaths were disproportionately higher than our encounter rates with the species within the snake community. This suggests racers were susceptible to fence mortality more so than Northern Pacific Rattlesnakes (Crotalus o. oreganus) or Great Basin Gophersnakes (Pituouphis catenifer deserticola). Datalogger recordings revealed temperatures under cover boards were well above the tolerable temperatures of the three snake species, although the boards appeared to temper ambient heat more efficiently than natural vegetation. We caution that the effects of fencing and cover boards may vary across ecosystems and snake species

A pivotal role for starch in the reconfiguration of 14C-partitioning and allocation in Arabidopsis thaliana under short-term abiotic stress.

Plant carbon status is optimized for normal growth but is affected by abiotic stress. Here, we used 14C-labeling to provide the first holistic picture of carbon use changes during short-term osmotic, salinity, and cold stress in Arabidopsis thaliana. This could inform on the early mechanisms plants use to survive adverse environment, which is important for efficient agricultural production. We found that carbon allocation from source to sinks, and partitioning into major metabolite pools in the source leaf, sink leaves and roots showed both conserved and divergent responses to the stresses examined. Carbohydrates changed under all abiotic stresses applied; plants re-partitioned 14C to maintain sugar levels under stress, primarily by reducing 14C into the storage compounds in the source leaf, and decreasing 14C into the pools used for growth processes in the roots. Salinity and cold increased 14C-flux into protein, but as the stress progressed, protein degradation increased to produce amino acids, presumably for osmoprotection. Our work also emphasized that stress regulated the carbon channeled into starch, and its metabolic turnover. These stress-induced changes in starch metabolism and sugar export in the source were partly accompanied by transcriptional alteration in the T6P/SnRK1 regulatory pathway that are normally activated by carbon starvation

A missense variant in CST3 exerts a recessive effect on susceptibility to age-related macular degeneration resembling its association with Alzheimer’s disease

Age-related macular degeneration (AMD) and Alzheimer’s disease (AD) are degenerative, multifactorial diseases involving age-related accumulation of extracellular deposits linked to dysregulation of protein homeostasis. Here, we strengthen the evidence that an nsSNP (p.Ala25Thr) in the cysteine proteinase inhibitor cystatin C gene CST3, previously confirmed by meta-analysis to be associated with AD, is associated with exudative AMD. To our knowledge, this is the first report highlighting a genetic variant that increases the risk of developing both AD and AMD. Furthermore, we demonstrate that the risk associated with the mutant allele follows a recessive model for both diseases. We perform an AMD-CST3 case–control study genotyping 350 exudative AMD Caucasian individuals. Bringing together our data with the previously reported AMD-CST3 association study, the evidence of a recessive effect on AMD risk is strengthened (OR = 1.89, P = 0.005). This effect closely resembles the AD-CST3 recessive effect (OR = 1.73, P = 0.005) previously established by meta-analysis. This resemblance is substantiated by the high correlation between CST3 genotype and effect size across the two diseases (R2 = 0.978). A recessive effect is in line with the known function of cystatin C, a potent enzyme inhibitor. Its potency means that, in heterozygous individuals, a single functional allele is sufficient to maintain its inhibitory function; only homozygous individuals will lack this form of proteolytic regulation. Our findings support the hypothesis that recessively acting variants account for some of the missing heritability of multifactorial diseases. Replacement therapy represents a translational opportunity for individuals homozygous for the mutant allele