Ecosystem process models at multiple scales for mapping tropical forest productivity

Quantifying mass and energy exchanges within tropical forests is essential for understanding their role in the global carbon budget and how they will respond to perturbations in climate. This study reviews ecosystem process models designed to predict the growth and productivity of temperate and tropical forest ecosystems. Temperate forest models were included because of the minimal number of tropical forest models. The review provides a multiscale assessment enabling potential users to select a model suited to the scale and type of information they require in tropical forests. Process models are reviewed in relation to their input and output parameters, minimum spatial and temporal units of operation, maximum spatial extent and time period of application for each organization level of modelling. Organizational levels included leaf-tree, plot-stand, regional and ecosystem levels, with model complexity decreasing as the time-step and spatial extent of model operation increases. All ecosystem models are simplified versions of reality and are typically aspatial. Remotely sensed data sets and derived products may be used to initialize, drive and validate ecosystem process models. At the simplest level, remotely sensed data are used to delimit location, extent and changes over time of vegetation communities. At a more advanced level, remotely sensed data products have been used to estimate key structural and biophysical properties associated with ecosystem processes in tropical and temperate forests. Combining ecological models and image data enables the development of carbon accounting systems that will contribute to understanding greenhouse gas budgets at biome and global scales.

Variable effects of larval size on post-metamorphic performance in the field

Larval quality may be capable of explaining much of the variation in the recruitment and subsequent population dynamics of benthic marine invertebrates. Whilst the effects of larval nutritional condition on adult performance have received the most attention, recent work has shown that larval size may also be an important and ubiquitous source of variation in larval quality. We examined the effects of variation in larval size on the post-metamorphic survival and growth of Watersipora subtorquata in 2 very different habitats - experimental substrata and pier pilings. We found strong effects of larval size on colony performance, although these varied among experiments. For colonies on experimental substrata, larval size positively affected adult survival and, initially, growth. However, after 3 wk in the field, there was no relationship between larval size and colony size, possibly because colonies were completely surrounded by newly settled organisms. Larval size also positively affected post-metamorphic growth of colonies on pier pilings, but, surprisingly, colonies that came from larger larvae had lower survival than colonies from smaller larvae. Overall, variation in larval size will strongly affect the recruitment and subsequent performance of adults in this species, although this may vary among different habitats. This study highlights the importance of examining the effects of larval quality on adult performance in as realistic conditions as possible, because of the strong interaction between larval size effects and the environment.

Superior electric double layer capacitors using ordered mesoporous carbons

This paper reports for the first time superior electric double layer capacitive properties of ordered mesoporous carbon (OMCs) with varying ordered pore symmetries and mesopore structure. Compared to commercially used activated carbon electrode, Maxsorb, these OMC carbons have superior capacitive behavior, power output and high-frequency performance in EDLCs due to the unique structure of their mesopore network, which is more favorable for fast ionic transport than the pore networks in disordered microporous carbons. As evidenced by N-2 sorption, cyclic voltammetry and frequency response measurements, OMC carbons with large mesopores, and especially with 2-D pore symmetry, show superior capacitive behaviors (exhibiting a high capacitance of over 180 F/g even at very high sweep rate of 50 mV/s, as compared to much reduced capacitance of 73 F/g for Maxsorb at the same sweep rate). OMC carbons can provide much higher power density while still maintaining good energy density. OMC carbons demonstrate excellent high-frequency performances due to its higher surface area in pores larger than 3 nm. Such ordered mesoporous carbons (OMCs) offer a great potential in EDLC capacitors, particularly for applications where high power output and good high-frequency capacitive performances are required. (C) 2005 Elsevier Ltd. All rights reserved.

Bernard Michael Bindon - reproductive physiologist, animal scientist, research leader

This paper is a foreword to a series of papers commissioned on 'the impact of science on the beef industry', where the Beef CRC-related collaborative scientific work of Professor Bernard Michael Bindon will be reviewed. These papers will be presented in March 2006, as part of a 'festschrift' to recognise his wider contributions to the Australian livestock industries for over 40 years. Bindon's career involved basic and applied research in many areas of reproductive physiology, genetics, immunology, nutrition, meat science and more recently genomics, in both sheep and cattle. Together with his collaborators, he made large contributions to animal science by improving the knowledge of mechanisms regulating reproductive functions and in elucidating the physiology and genetics of high fecundity livestock. His collaborative studies with many colleagues of the reproductive biology and genetics of the Booroola Merino were amongst the most extensive ever conducted on domestic livestock. He was instrumental in the development of immunological techniques to control ovulation rate and in examining the application of these and other techniques to increase beef cattle reproductive output. This paper tracks his investigations and achievements both within Australia and internationally. In the later stages of his career he was the major influence in attracting a large investment in Cooperative Research Centres for the Australian cattle industry, in which he directed a multi-disciplinary approach to investigate, develop and disseminate science and technology to improve commercial cattle productivity.

Pure two-atom squeezed state in spontaneous emission from two non-identical atoms

We calculate the stationary state of the system of two non-identical two-level atoms driven by a finite-bandwidth two-mode squeezed vacuum. It is well known that two identical two-level atoms driven by a broadband squeezed vacuum may decay to a pure state, called the pure two-atom squeezed state, and that the presence of the antisymmetric state can change its purity. Here, we show that for small interatomic separations the stationary state of two non-identical atoms is not sensitive to the presence of the antisymmetric state and is the pure two-atom squeezed state. This effect is a consequence of the fact that in the system of two non-identical atoms the antisymmetric state is no longer the trapping state. We also calculate the squeezing properties of the emitted field and find that the squeezing spectrum of the output field may exhibit larger squeezing than that in the input squeezed vacuum. Moreover, we show that squeezing in the total field attains the optimum value which can ever be achieved in the field emitted by two atoms.

Squeezing in anomalous resonance fluorescence

The squeezing properties of the fluorescence field emitted by a two-level atom driven by a coherent laser field in a squeezed vacuum are calculated. We show that in the region of the anomalous resonance fluorescence the emitted field exhibits squeezing that is much larger than that in the input squeezed vacuum. The squeezing spectrum attains a minimum value that corresponds to 75% squeezing. We also find that, in the total fluorescence field, squeezing attains an optimum achievable value in the fluorescence field emitted by a two-level atom. The optimum squeezing is associated with the collapse of the system into a pure state. (C) 1997 Optical Society of America.

A controlled trial comparing the efficacy of rice-based and hypotonic glucose oral rehydration solutions in infants and young children with gastroenteritis

A prospective randomized trial was conducted to compare the efficacy of a rice-based oral rehydration solution (ORS) with glucose ORS in infants and children under 5 years of age with acute diarrhoea and mild to moderate dehydration (<10%). One hundred children presenting to a large metropolitan teaching hospital were eligible for entry to the study and were randomized to receive rice ORS or glucose ORS. Outcome measures were stool output (SO), duration of illness (DD) and recovery time to introduction of other fluids (RTF) and diet (RTD). Significant differences were found for all outcome measures in favour of the rice ORS group. Mean SO was lower (160 vs 213 mt; P<0.02), mean DD was reduced (17.3 vs 24.3 h; P = 0.03) and median RTF was decreased (12.7 vs 18.1 h; P< 0.001) in the rice ORS group compared with the glucose ORS group. The median rime to introduction of diet and mean length of hospital stay showed similar significant reductions. Our study has shown rice ORS to be an acceptable alternative to glucose ORS in young children and have shown that it is significantly more effective in reducing the course of diarrhoeal illness and the time taken to return to normal drinking and eating habits.

Energy turnover in the normoxic and anoxic turtle heart

We examined the possibility that the heart of the turtle Chrysemys scripta is an exceptional anaerobic performer, by measuring myocardial power output, lactate output, and estimated ATP turnover in perfused heart preparations. Over a range of myocardial power outputs at 5 and 15 degrees C we find that turtle hearts perfused with anoxic saline do not show a particularly outstanding ability to produce ATP anaerobically. Furthermore, at 15 degrees C anoxia reduced the ATP turnover rate to 50% of the normoxic rate. At 5 degrees C the anoxia-induced depression of ATP turnover was even more pronounced, being 4-fold lower than the normoxic rate. In addition, anoxia at 5 degrees C reduced the basal metabolic rate of the turtle heart. We conclude that long-term cardiac tolerance of hypoxia in this species is more likely related to metabolic depression rather than to an exceptional anaerobic performance. (C) 1997 Elsevier Science Inc.

Optimal quantum measurements for phase-shift estimation in optical interferometry

Quantum information theory, applied to optical interferometry, yields a 1/n scaling of phase uncertainty Delta phi independent of the applied phase shift phi, where n is the number of photons in the interferometer. This 1/n scaling is achieved provided that the output state is subjected to an optimal phase measurement. We establish this scaling law for both passive (linear) and active (nonlinear) interferometers and identify the coefficient of proportionality. Whereas a highly nonclassical state is required to achieve optimal scaling for passive interferometry, a classical input state yields a 1/n scaling of phase uncertainty for active interferometry.

Forecasting regional crop production using SOI phases: an example for the Australian peanut industry

Using peanuts as an example, a generic methodology is presented to forward-estimate regional crop production and associated climatic risks based on phases of the Southern Oscillation Index (SOI). Yield fluctuations caused by a highly variable rainfall environment are of concern to peanut processing and marketing bodies. The industry could profitably use forecasts of likely production to adjust their operations strategically. Significant, physically based lag-relationships exist between an index of ocean/atmosphere El Nino/Southern Oscillation phenomenon and future rainfall in Australia and elsewhere. Combining knowledge of SOI phases in November and December with output from a dynamic simulation model allows the derivation of yield probability distributions based on historic rainfall data. This information is available shortly after planting a crop and at least 3-5 months prior to harvest. The study shows that in years when the November-December SOI phase is positive there is an 80% chance of exceeding average district yields. Conversely, in years when the November-December SOI phase is either negative or rapidly falling there is only a 5% chance of exceeding average district yields, but a 95% chance of below average yields. This information allows the industry to adjust strategically for the expected volume of production. The study shows that simulation models can enhance SOI signals contained in rainfall distributions by discriminating between useful and damaging rainfall events. The methodology can be applied to other industries and regions.

Commercialisation of agriculture in Kenya: Case study of urban bias on food availability in farm households

This study investigates the effect of cash cropping on food availability and examines the determinants of the proportion of income allocated for food expenditures in the Nyeri district in Kenya. Using a Tobit model, the results suggest that in general food expenditure allocations suffer due to cash cropping in Kenya as the lump-sum income flows from this may be used for purchases other than food. Food expenditure also suffers when remittances are irregular. On the other hand, earnings from outside employment for married women living with husbands are positively associated with food expenditure allocations. Amounts of non-cash food output as well as ownership of livestock are negatively associated with food expenditure allocations. These findings indicate that lump sum income may not lead to improved welfare of women and children. Thus, there may be social reasons for increasing non-cash food production especially by women, instead of over emphasizing cash cropping as now seems to be so in public policy.

Marital status, farm size and other influences on the extent of cash cropping in Kenya: A household case study

This article examines the effects of marital status, farm size and other factors on the extent of cash cropping (and allocation of land use) by means of a case study in the Nyeri district in Kenya. It was found that married women are involved in the production of a relatively greater amount of output of cash crops than unmarried women since husbands prefer to have more land under cash crops than food crops. Farmers with better quality land allocate a high proportion of it to non-food cash crops, which may expose some households to greater risks of possible famine. The proportion of land allocated to food crops declines as the farm size increases while the proportion of land allocated to non-food cash crops rises as the size of farm increases. Age is also inversely associated with subsistence. Education, though inversely associated with subsistence farming does not appear to be statistically very significant as an influence on the composition of land use and composition of farm output. With growing commercialisation, married women work more hours than unmarried ones, working not only on non-cash food crops but also on non-food cash crops. Married women seem to lose their decision-making ability with growth of agricultural commercialisation, as husbands make most decisions to do with cash crops. Married women in Kenya also have little or no power to change the way land is allocated between food and non-food cash crops.

Anisotropy-based performance analysis of linear discrete time invariant control systems

The anisotropic norm of a linear discrete-time-invariant system measures system output sensitivity to stationary Gaussian input disturbances of bounded mean anisotropy. Mean anisotropy characterizes the degree of predictability (or colouredness) and spatial non-roundness of the noise. The anisotropic norm falls between the H-2 and H-infinity norms and accommodates their loss of performance when the probability structure of input disturbances is not exactly known. This paper develops a method for numerical computation of the anisotropic norm which involves linked Riccati and Lyapunov equations and an associated special type equation.

A flux ratio theorem for multicomponent linear diffusion equations

Ussing [1] considered the steady flux of a single chemical component diffusing through a membrane under the influence of chemical potentials and derived from his linear model, an expression for the ratio of this flux and that of the complementary experiment in which the boundary conditions were interchanged. Here, an extension of Ussing's flux ratio theorem is obtained for n chemically interacting components governed by a linear system of diffusion-migration equations that may also incorporate linear temporary trapping reactions. The determinants of the output flux matrices for complementary experiments are shown to satisfy an Ussing flux ratio formula for steady state conditions of the same form as for the well-known one-component case. (C) 2000 Elsevier Science Ltd. All rights reserved.

The effects of normalisation on the ability of business end-users to detect data anomalies: An experimental evaluation

With the proliferation of relational database programs for PC's and other platforms, many business end-users are creating, maintaining, and querying their own databases. More importantly, business end-users use the output of these queries as the basis for operational, tactical, and strategic decisions. Inaccurate data reduce the expected quality of these decisions. Implementing various input validation controls, including higher levels of normalisation, can reduce the number of data anomalies entering the databases. Even in well-maintained databases, however, data anomalies will still accumulate. To improve the quality of data, databases can be queried periodically to locate and correct anomalies. This paper reports the results of two experiments that investigated the effects of different data structures on business end-users' abilities to detect data anomalies in a relational database. The results demonstrate that both unnormalised and higher levels of normalisation lower the effectiveness and efficiency of queries relative to the first normal form. First normal form databases appear to provide the most effective and efficient data structure for business end-users formulating queries to detect data anomalies.