Feeding frequency and parental division of labour in the double-brooded great tit Parus major

Summary We studied the relative contribution of each sex and total effort expended in feeding nestlings in the great tit Parus major in relation to artificially altered brood size. A recent model suggests that feeding frequency should reflect the optimal trade-off between parental and fledgling survival, the former being negatively, the latter positively, influenced by high feeding frequencies. In both sexes weight loss was linearly related to feeding frequency. Since fledgling survival increases with nestling weight, the conditions of this model are fulfilled. However, in contrast to the predictions of the model, the total feeding frequency for both sexes combined did not differ between control and enlarged broods, but was lower for reduced ones. This outcome was not the result of a physiologically related inability of the parents to increase their delivery rate. Instead, we suggest that parents with enlarged broods could not find sufficient amounts of prey large enough to be economically worth transporting to the nest. Differences in brood-provisioning rates between the sexes may arise because costs and benefits of feeding nestlings may differ. Females lost more weight than males during the nesting period, but maintained a relatively higher weight during the incubation period. The relationship between weight loss and feeding frequency was similar for both sexes. Male and female brood-feeding frequency was related to brood size in a similar way. This is discussed in light of the great tit's mating system and the fact that the great tit is facultatively double-brooded.     

Environmental education for engineers: An Australian viewpoint

Summary Australian engineering undergraduate courses of 1987 are described as being devoid of any real environmental content. It is suggested that this is an important omission, for engineers should have a duty to consider the environmental impact of their works. Possible ways in which an environmental component could be added to existing engineering courses are outlined.Prepared by the Environmental Education Subcommittee of the Environmental Engineering Panel of the Sydney Division of the Institution of Engineers, AustraliaHans Bandler is a member of the Environmental Engineering Panel of the Sydney Division of the Institution of Engineers, Australia and its Environmental Education Subcommittee. This paper was prepared and distributed as a Discussion Paper on Environmental Education for Engineering Undergraduates in April, 1987. Preparation of the paper was assisted by a draft document from the Institution of Engineers, Australia's National Committee on Environmental Engineering.     

Food,feed, and fuelwood resources of Nepal: A GIS evaluation

A GIS-based land evaluation model was developed to determine the food, feed, and fuelwood sufficiency of all districts in Nepal. Resource surpluses or deficits were calculated for each district for 1981, the year for which the national land resource data were available. Of the three resources, feed supplies were found to be the most critical. Feed deficits occurred in 57% of all districts in 1981, while food and fuelwood deficits occurred in less than 10% of all districts. Different scenarios were carried out for the year 2000 to estimate the magnitude of future resource deficits, assuming resource use and yields in Nepal remain constant in the face of growing population and livestock numbers. Linking resource data with spreadsheet and GIS systems provides a new way to understand and evaluate resources at the district and national levels. To more fully capture the usefulness of this approach, information on rates of change in productivity and land use is needed.     

Diffusion scrubber technique used for measurements of atmospheric ammonia

A diffusion scrubber (DS) was developed to measure trace levels of gaseous ammonia in ambient air. The sampling resolution time for this method is 10 min and the detection limit is estimated to be 0.01 ppbv. The response to the NI-I₃ concentrations is found to be dependent on the relative humidity in the ambient air and the temperature. The method is calibrated by using a diluted NH₃ cylinder gas, and the concentrations of the calibration gas were in the range 0.02–2 ppbv during the test. Sampling performed with the DS-method is compared to sampling performed by a filter pack and a continuous flow denuder (AMANDA). The DS-method shows good agreement with the continuous flow denuder and the filter pack.     

Population Monitoring of the Coelacanth (Latimeria chalumnae)

In 1991 the population size of the coelacanth (   Latimeria chalumnae ) on Grande Comore Island, Western Indian Ocean, was estimated at 230–650 individuals, based on counts of individually recognized fish in an 8-km stretch of coastline. This census area represents about 9% of the total suitable habitat at the island. Counts in the same area in 1994 indicated a reduction of sighted coelacanths of about 30%. Additional surveys in 1995 suggested a total coelacanth population of less than 300 individuals. The local artisanal fishery is probably responsible for the observed decline. The survival of the coelacanth seems to be severely threatened if fishing pressure is not reduced. Conservation measures should focus on providing local fishermen with fishing alternatives.

Monitoreo Poblacional del Celacanto ( Latimeria chalumnae )

En 1991 el tamaño poblacional del celacanto, Latimeria chalumnae en Grande Comore, al Oeste del Oceano Indico, fue estimada de 230 a 650 individuos, en base a conteos de individuos reconocidos en un estrecho costero de 8 km de longitud. Esta área de censo representa cerca de un 9% del total de hábitat adecuado en la isla. Los conteos en la zona en 1994 indicaron una reducción de celacantos de aproximadamnete un 30%. Estudios adicionales en 1995 sugirieron una población total de menos de 300 individuos. Probablemente la pesqueria artesanal local es responsable de la declinación observada. La sobrevivencia del celacanto aparenta estar amenazada si la presion por pesca no disminuye. Las medidas de conservación se deberan enfocar en proveer a los pescadores locales de alternataivas de pesca.     

Status and trends of tundra birds across the circumpolar Arctic

Tundra-breeding birds face diverse conservation challenges, from accelerated rates of Arctic climate change to threats associated with highly migratory life histories. Here we summarise the status and trends of Arctic terrestrial birds (88 species, 228 subspecies or distinct flyway populations) across guilds/regions, derived from published sources, raw data or, in rare cases, expert opinion. We report long-term trends in vital rates (survival, reproduction) for the handful of species and regions for which these are available. Over half of all circumpolar Arctic wader taxa are declining (51% of 91 taxa with known trends) and almost half of all waterfowl are increasing (49% of 61 taxa); these opposing trends have fostered a shift in community composition in some locations. Declines were least prevalent in the African-Eurasian Flyway (29%), but similarly prevalent in the remaining three global flyways (44–54%). Widespread, and in some cases accelerating, declines underscore the urgent conservation needs faced by many Arctic terrestrial bird species.     

The potential of SO2 for reducing corrosion in WtE plants

Due to the high-temperature boiler corrosion induced by chloride-rich fly ash deposits, steam generation in today’s Waste-to-Energy (WtE) plants is typically designed only for 40 bar/400 °C as an economic compromise between acceptable corrosion rate and maximum power generation. The high-corrosive metal chlorides in the fly ash can react with SO₂ forming low-corrosive sulfates. The sulfation efficiency is enhanced by high SO₂ levels and sufficient residence time of the flue gas at high-temperatures (700–900 °C). The fly ash sulfation was tested in full scale in a Swedish WtE plant by applying the economic sulfur recirculation method. Probes of several alloys (16Mo3, Inconel 625, Sanicro 28) were exposed for 1000 h at controlled material temperatures in the superheater position, at normal and during sulfating operation respectively. Analyses of the fly ash showed that the molar Cl/S was decreased to values well below 1 and the corresponding corrosion rates of the individual material samples were less than half when sulfur recirculation was in operation. These positive findings demonstrate that the sulfur recirculation process has high potential for low-corrosive high-temperature steam generation (T ≈ 500 °C) and improved electricity production. Further steam superheating can be realized by staged superheating using small amounts of secondary fuel.