The effect of life expectancy on fertility, saving, schooling and economic growth: theory and evidence

We construct a simple growth model where agents with uncertain survival choose schooling time, life-cycle consumption and the number of children. We show that rising longevity reduces fertility but raises saving, schooling time and the growth rate at a diminishing rate. Cross-section analyses using data from 76 countries support these propositions: life expectancy has a significant positive effect on the saving rate, secondary school enrollment and growth but a significant negative effect on fertility. Through sensitivity analyses, the effect on the saving rate is inconclusive, while the effects on the other variables are robust and consistent. These estimated effects are decreasing in life expectancy. Copyright The editors of the Scandinavian Journal of Economics 2005.

The life cycle of Paracardicoloides yamagutii Martin, 1974 (Digenea: Sanguinicolidae)

The sanguinicolids Paracardicoloides yamagutii Martin, 1974 and Plethorchis acanthus Martin, 1975 were obtained from their definitive hosts, Anguilla reinhardtii Steindachner and Mugil cephalus Linnaeus (respectively) in the tributaries of the Brisbane River, Queensland, Australia. Two putative sanguinicolid cercariae were collected from a hydrobiid gastropod, Posticobia brazieri Smith, in the same waters. The two cercariae differ markedly in size and the form of their sporocysts. Both putative cercariae develop in the digestive gland of Po. brazieri. The ITS2 rDNA region from these sanguinicolids and a Clinostomum species (utilised as an outgroup due to the close morphological similarities between the cercarial stages of the Clinostomidae and the Sanguinicolidae) were sequenced and aligned. Comparison of the ITS2 sequences showed one cercaria to be that of P. yamagutii. This is the first sanguinicolid life history determined by a molecular method. P. yamagutii is the fourth sanguinicolid known to utilise a freshwater hydrobiid gastropod as its intermediate host. ITS2 rDNA is effective in distinguishing sanguinicolids at the species level.

Fuel cells, hydrogen and energy supply in Australia

Australia is unique in terms of its geography, population distribution, and energy sources. It has an abundance of fossil fuel in the form of coal, natural gas, coal seam methane (CSM), oil, and a variety renewable energy sources that are under development. Unfortunately, most of the natural gas is located so far away from the main centres of population that it is more economic to ship the energy as LNG to neighboring countries. Electricity generation is the largest consumer of energy in Australia and accounts for around 50% of greenhouse gas emissions as 84% of electricity is produced from coal. Unless these emissions are curbed, there is a risk of increasing temperatures throughout the country and associated climatic instability. To address this, research is underway to develop coal gasification and processes for the capture and sequestration Of CO2. Alternative transport fuels such as biodiesel are being introduced to help reduce emissions from vehicles. The future role of hydrogen is being addressed in a national study commissioned this year by the federal government. Work at the University of Queensland is also addressing full-cycle analysis of hydrogen production, transport, storage, and utilization for both stationary and transport applications. There is a modest but growing amount of university research in fuel cells in Australia, and an increasing interest from industry. Ceramic Fuel Cells Ltd. (CFCL) has a leading position in planar solid oxide fuel cells (SOFCs) technology, which is being developed for a variety of applications, and next year Perth in Western Australia is hosting a trial of buses powered by proton-exchange fuel cells. (C) 2004 Elsevier B.V. All rights reserved.

Life Cycle Assessment (LCA) Applied to the Design of an Innovative Drying Process for Sewage Sludge

Most adverse environmental impacts result from design decisions made long before manufacturing or usage. In order to prevent this situation, several authors have proposed the application of life cycle assessment (LCA) at the very first phases of the design of a process, a product or a service. The study in this paper presents an innovative thermal drying process for sewage sludge called fry-drying, in which dewatered sludge is directly contacted in the dryer with hot recycled cooking oils (RCO) as the heat medium. Considering the practical difficulties for the disposal of these two wastes, fry-drying presents a potentially convenient method for their combined elimination by incineration of the final fry-dried sludge. An analytical comparison between a conventional drying process and the new proposed fry-drying process is reported, with reference to some environmental impact categories. The results of this study, applied at the earliest stages of the design of the process, assist evaluation of the feasibility of such system compared to a current disposal process for the drying and incineration of sewage sludge.

The origin of the pelagobenthic metazoan life cycle: what's sex got to do with it?

The biphasic (pelagobenthic) life cycle is found throughout the animal kingdom, and includes gametogenesis, embryogenesis, and metamorphosis. From a tangled web of hypotheses on the origin and evolution of the metazoan pelagobenthic life cycle, current opinion appears to favor a simple, larval-like holopelagic ancestor that independently settled multiple times to incorporate a benthic phase into the life cycle. This hypothesis derives originally from Haeckel's (1874) Gastraea theory of ontogeny recapitulating phylogeny, in which the gastrula is viewed as the recapitulation of a gastracan ancestor that evolved via selection on a simple, planktonic hollow ball of cells to develop the capacity to feed. Here, we propose an equally plausible hypothesis that the origin of the metazoan pelagobenthic life cycle was a direct consequence of sexual reproduction in a likely holobenthic ancestor. In doing so, we take into account new insights from poriferan development and from molecular phylogenies. In this scenario, the gastrula does not represent a recapitulation, but simply an embryological stage that is an outcome of sexual reproduction. The embryo can itself be considered as the precursor to a biphasic lifestyle, with the embryo representing one phase and the adult another phase. This hypothesis is more parsimonious because it precludes the need for multiple, independent origins of the benthic form. It is then reasonable to consider that multilayered, ciliated embryos ultimately released into the water column are subject to natural selection for dispersal/longevity/feeding that sets them on the evolutionary trajectory towards the crown metazoan planktonic larvae. These new insights from poriferan development thus clearly support the intercalation hypothesis of bilaterian larval evolution, which we now believe should be extended to discussions of the origin of biphasy in the metazoan last common ancestor.