Begging and food distribution in crimson rosella (Platycercus elegans) broods: why don't hungry chicks beg more?

Altricial nestlings solicit food by begging and engaging in scramble competition. Solicitation displays can thus signal both hunger and competitive ability. I examined nestling solicitation and parental responses in crimson rosellas (Platycercus elegans), a species in which parents engage in complex patterns of food allocation and appear to control the distribution of food. By manipulating the hunger of individual chicks and entire broods, I assessed how chick behaviours and parental food allocation varied with hatching rank, level of hunger, and intensity of nestling competition. Last-hatched chicks begged more than first-hatched chicks irrespective of individual hunger levels. The two parents combined fed individually hungry chicks more, but mothers and fathers varied in their responses to begging chicks: fathers fed last-hatched chicks in proportion to their begging intensity, whereas mothers fed chicks equally. Since fathers generally allocate more food to first-hatched chicks, fathers appear to use begging rates to adjust food allocation to non-preferred chicks within the brood. When I manipulated brood hunger levels, begging rates increased for first- and last-hatched chicks suggesting that chick begging rates are sensitive to the level of competition. This study shows that begging by rosella chicks does not correlate with hunger in a straightforward way and that the primary patterns of food allocation by parents art: not influenced by chick begging. Thus the benefits of increased begging may be limited for nestlings in this species.

Canopy carbon and oxygen isotope composition of 9-year-old hoop pine families in relation to seedling carbon isotope composition, growth, field growth performance, and canopy nitrogen concentration

Carbon isotope composition (delta C-13), oxygen isotope composition (delta O-18), and nitrogen concentration (N-mass) of branchlet tissue at two canopy positions were assessed for glasshouse seedlings and 9-year-old hoop pine (Araucaria cunninghamii Ait. ex D. Don) trees from 22 open-pollinated families grown in 5 blocks of a progeny test at a water-limited and nitrogen-deficient site in southeastern Queensland, Australia. Significant variations in canopy delta C-13, delta O-18, and N-mass existed among the 9-year-old hoop pine families, with a heritability estimate of 0.72 for branchlet delta C-13 from the upper inner canopy position. There was significant variation in canopy delta C-13 of glasshouse seedlings between canopy positions and among the families, with a heritability estimate of 0.66. The canopy delta C-13 was positively related to canopy N-mass only for the upper outer crown in the field (R = 0.62, p < 0.001). Phenotypic correlations existed between tree height and canopy delta C-13 (R = 0.37-0.41, p < 0.001). Strong correlations were found between family canopy delta C-13 at this site and those at a wetter site and between field canopy delta C-13 and glasshouse seedling delta C-13. The mechanisms of the variation in canopy delta C-13 are discussed in relation to canopy photosynthetic capacity as reflected in the N-mass and stomatal conductance as indexed by canopy delta O-18.

The impact of nutrition support on body composition in cancer outpatients receiving radiotherapy

This study investigated the change in body composition in 36 cancer outpatients receiving radiotherapy to the head and neck area (mean age: 63 ± 15 years) randomised to receive either nutrition intervention (NI; n=15) or usual care (UC; n=21). Body weight and composition were measured at the commencement of radiotherapy and 3 months later. The UC group lost significantly more weight; mean decrease = 4.3 kg, than the NI group: mean decrease = 1.1 kg (t(30)=-2.5, p=0.019). Fat-free mass loss was significantly higher in the UC group with a mean loss of 2.2 kg versus 0.3 kg in the NI group (t(30)=- 2.3, p=0.029). Body composition as measured by foot-to-foot bioelectrical impedance analysis provides more information than weight alone and can allow for tailoring of NI.

Relationship of high energy expenditure and variation in dietary intake with reporting accuracy on 7 day food records and diet histories in a group of healthy adult volunteers

Objectives: To assess the accuracy of reporting from both a diet history and food record and identify some of the characteristics of more accurate reporters in a group of healthy adult volunteers for an energy balance study. Design: Prospective measurements in free-living people. Setting: Wollongong, Australia. Subjects: Fifteen healthy volunteers (seven male, eight female; aged 22 -59 y; body mass index (BMI) 19 - 33 kg/m(2)) from the local community in the city of Wollongong, Australia. Interventions: Measurement of energy intake via diet history interview and 7 day food records, total energy expenditure by the doubly labelled water technique over 14 days, physical activity by questionnaire, and body fat by dual-energy X-ray absorptiometry. Results: Increased misreporting of energy intake was associated with increased energy expenditure (r = 0.90, P < 0.0001, diet history; r(s)=0.79, P=0.0005, food records) but was not associated with age, sex, BMI or body fat. Range in number of recorded dinner foods correlated positively with energy expenditure (r(s)=0.63, P=0.01) and degree of misreporting (r(s)=0.71, P=0.003, diet history; r(s)=0.63, P=0.01, food records). Variation in energy intake at dinner and over the whole day identified by the food records correlated positively with energy expenditure (r=0.58, P = 0.02) and misreporting on the diet history (r=0.62, P=0.01). Conclusions: Subjects who are highly active or who have variable dietary and exercise behaviour may be less accurate in reporting dietary intake. Our findings indicate that it may be necessary to screen for these characteristics in studies where accuracy of reporting at an individual level is critical. Sponsorship: The study was supported in part by Australian Research Council funds made available through the University of Wollongong.

Can the nitrogenous composition of xylem sap be used to assess salinity stress in Casuarina glauca?

It is predicted that dryland salinity will affect up to 17 Mha of the Australian landscape by 2050, and therefore, monitoring the health of tree plantings and remnant native vegetation in saline areas is increasingly important. Casuarina glauca Sieber ex Spreng. has considerable salinity tolerance and is commonly planted in areas with a shallow, saline water table. To evaluate the potential of using the nitrogenous composition of xylem sap to assess salinity stress in C. glauca, the responses of trees grown with various soil salinities in a greenhouse were compared with those of trees growing in field plots with different water table depths and groundwater salinities. In the greenhouse, increasing soil salinity led to increased allocation of nitrogen (N) to proline and arginine in both stem and root xylem sap, with coincident decreases in citrulline and asparagine. Although the field plots were ranked as increasingly saline-based on ground water salinity and depth-only the allocation of N to citrulline differed significantly between the field plots. Within each plot, temporal variation in the composition of the xylem sap was related to rainfall, rainfall infiltration and soil salinity. Periods of low rainfall and infiltration and higher soil salinity corresponded with increased allocation of N to proline and arginine in the xylem sap. The allocation of N to citrulline and asparagine increased following rainfall events where rain was calculated to have infiltrated sufficiently to decrease soil salinity. The relationship between nitrogenous composition of the xylem sap of C. glauca and soil salinity indicates that the analysis of xylem sap is an effective method for assessing changes in salinity stress in trees at a particular site over time. However, the composition of the xylem sap proved less useful as a comparative index of salinity stress in trees growing at different sites.

Eating 'Green': Motivations behind organic food consumption in Australia

Central to the development of green lifestyles is the consumption of foods that by dint of their status as chemical-free, locally produced and/or free of genetically modified ingredients, reduce the environmental impact of food provision. Yet there are many other factors, such as health concerns, that may also encourage the consumption of 'green' foods. This paper explores the ways in which Australian consumers construct organic food-a sector of the food industry that is currently growing at between 20 and 50 percent per annum but is struggling to keep up with rising consumer demand. In order to examine the significance of 'green' signifiers in the consumption practices of Australian consumers a series of focus group interviews and a national consumer survey were conducted. These examined both those characteristics of food that were valued in general, and those meanings that were associated with organic food in particular. In very general terms, analysis reveals that while consumers believed organic foods to be healthy and environmentally sound-both of which were considered desirable-these characteristics were subsumed by an overarching concern with convenience. This does not mean that consumers did not hold genuinely positive environmental attitudes. Rather, it reflects a range of contradictory beliefs and practices that appeared to derive from the discursive conflict between conventional and organic food industries over environmental, health and safety claims. The paper concludes by identifying the barriers and opportunities for expanding the organic industry in Australia in the context of the ways organics is constructed by consumers.

Monitoring the composition and form of urban environments based on the vegetation-impervious surface-soil (VIS) model by sub-pixel analysis techniques

The majority of the world's population now resides in urban environments and information on the internal composition and dynamics of these environments is essential to enable preservation of certain standards of living. Remotely sensed data, especially the global coverage of moderate spatial resolution satellites such as Landsat, Indian Resource Satellite and Systeme Pour I'Observation de la Terre (SPOT), offer a highly useful data source for mapping the composition of these cities and examining their changes over time. The utility and range of applications for remotely sensed data in urban environments could be improved with a more appropriate conceptual model relating urban environments to the sampling resolutions of imaging sensors and processing routines. Hence, the aim of this work was to take the Vegetation-Impervious surface-Soil (VIS) model of urban composition and match it with the most appropriate image processing methodology to deliver information on VIS composition for urban environments. Several approaches were evaluated for mapping the urban composition of Brisbane city (south-cast Queensland, Australia) using Landsat 5 Thematic Mapper data and 1:5000 aerial photographs. The methods evaluated were: image classification; interpretation of aerial photographs; and constrained linear mixture analysis. Over 900 reference sample points on four transects were extracted from the aerial photographs and used as a basis to check output of the classification and mixture analysis. Distinctive zonations of VIS related to urban composition were found in the per-pixel classification and aggregated air-photo interpretation; however, significant spectral confusion also resulted between classes. In contrast, the VIS fraction images produced from the mixture analysis enabled distinctive densities of commercial, industrial and residential zones within the city to be clearly defined, based on their relative amount of vegetation cover. The soil fraction image served as an index for areas being (re)developed. The logical match of a low (L)-resolution, spectral mixture analysis approach with the moderate spatial resolution image data, ensured the processing model matched the spectrally heterogeneous nature of the urban environments at the scale of Landsat Thematic Mapper data.

Global trade in GM food and the cartagena protocol on biosafety: Consequences for China

The UN Cartagena Protocol on Biosafety adopted in Montreal, 29 January, 2000 and opened for signature in Nairobi, 15-26 May, 2000 will exert a profound effect on international trade in genetically modified organisms (GMOs) and their products. In this paper, the potential effects of various articles of the Protocol on international trade in GMOs are analyzed. Based on the present status of imports of GMOs and domestic research and development of biotechnology in China, likely trends in imports of foreign GM food and related products after China accedes to WTO is explored. Also, China's potential countermeasures to control and regulate imports of GMOs in line with implementation of the Protocol are discussed. China, in recent times, has increased its food and agricultural imports substantially from USA and Canada. China imported soybean 10.42 mill. tons in 2000 and about 15 mill tons in 2001, of which majority are from USA where GM soybean accounts for 60%. The plantation of US Monsanto's transgenic Bt cotton was increased to more than 1 million ha in China in 2001. Though China has paid great attention to develop biotechnology, it appears to have little scope to export GMOs and GM products. So China may consider a range of administrative measures to implement the Cartagena Protocol and to regulate its import of GMOs and GM agricultural products. Consequently, the Regulation on Safety of Agri-GMOs was issued on June, 2001 and followed three detailed rules issued in Jan. of 2002, with a priority to limit foreign GMOs importing by safety certification and labeling system. These were outlined taking into account policies adopted in Western countries such as green barriers to international trade.

Alternative technologies for producing sterile low acid food products

Four emerging high-energy non-thermal technologies may replace or augment heating for producing sterile low-acid food products. High pressure, high-voltage pulsed electric field, high-energy ultrasound and high-intensity pulsed light are all capable of reducing bacterial spore counts under certain conditions. However, only non-continuous high pressure treatments, at temperatures higher than ambient, are currently capable of completely inactivating spores and producing sterile food products. The first three technologies also reduce the resistance of spores to inactivation by heat.