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Photooxygenations allow for the incorporation of molecular oxygen into substrates under mild and sustainable conditions. They only use light, oxygen and catalytic amounts of an organic dye to generate singlet oxygen (1O2), a short-lived reactive species, which can subsequently react with a multitude of functional groups within a substrate. Photooxygenations have found applications in fine chemical and pharmaceutical industries, for example in the manufacture of fragrances, building block chemicals and pharmaceuticals. Unlike batch processes, photooxygenations under flow conditions avoid accumulation of potentially explosive intermediates or products by continuously producing small amounts of materials, which can be subsequently quenched or converted safely. Continuous-flow reactors also allow for precise temperature control and the utilization of low-power light sources such as LEDs or OLEDs. The combination of flow operation, miniaturized dimensions and photooxygenations enables an environmentally friendly and safe adaptation to green organic synthesis. This chapter highlights various flow photoreactor technologies and successful examples of photooxygenations in flow.

Patterns of change in angler participation and demographics were examined for the recreational Atlantic salmon, Salmo salar L., fishery in Newfoundland and Labrador, Canada. An analysis of a licence stub return system, 1994–2010, showed a significant decline in resident angler participation, but this was not consistent across all regions of the Province. Mean age of anglers increased significantly, varying from 39.0 years in 1994 to 46.5 years by 2010. In some regions, mean age rose by over 12 years since the mid-1990s, reflecting a decline in the recruitment of younger anglers. The return rate of angler logs also declined over time and was found to vary by age, sex and area of angler residence. Women and older anglers, and those living in specific rural areas had a greater tendency to return a record of their catch history than men and younger anglers. Identified changes in participation and demographics, which can affect exploitation and ultimately abundance, could be used to develop management measures that would maximise both harvest and socio-economic benefits to the varied users of the resource.

SUMMARYWhen exposed to hot (22–35°C) and dry climatic conditions in the field during the final 4–6 weeks of pod filling, peanuts (Arachis hypogaeaL.) can accumulate highly carcinogenic and immuno-suppressing aflatoxins. Forecasting of the risk posed by these conditions can assist in minimizing pre-harvest contamination. A model was therefore developed as part of the Agricultural Production Systems Simulator (APSIM) peanut module, which calculated an aflatoxin risk index (ARI) using four temperature response functions when fractional available soil water was P⩽0·05) of the variation in aflatoxin contamination, which varied from 0 toc. 800 μg/kg in 17 large-scale sowings in tropical and four sowings in sub-tropical environments carried out in Australia between 13 November and 16 December 2007. ARI also explained 0·96 (P⩽0·01) of the variation in the proportion of aflatoxin-contaminated loads (>15 μg/kg) of peanuts in the Kingaroy region of Australia during the period between the 1998/99 and 2007/08 seasons. Simulation of ARI using historical climatic data from 1890 to 2007 indicated a three-fold increase in its value since 1980 compared to the entire previous period. The increase was associated with increases in ambient temperature and decreases in rainfall. To facilitate routine monitoring of aflatoxin risk by growers in near real time, a web interface of the model was also developed. The ARI predicted using this interface for eight growers correlated significantly with the level of contamination in crops (r=0·95,P⩽0·01). These results suggest that ARI simulated by the model is a reliable indicator of aflatoxin contamination that can be used in aflatoxin research as well as a decision-support tool to monitor pre-harvest aflatoxin risk in peanuts.

In insular Newfoundland, Canada, studies were conducted from 1999 to 2003 on the effects of ‘simulated’ hydropeaking power generation on juvenile Atlantic salmon (Salmo salar). In 1999, Atlantic salmon parr were released into an experimental reach below a hydroelectric facility and flow was manipulated over a range of discharge (1.0–4.2 m3 s−1) during a series of ‘experiments’ simulating hydropeaking in both summer and fall. Fish were implanted with radio transmitters, manually tracked, precisely located (±1 m), habitat selection evaluated, and movement response determined. Experiments were continued in 2002 and 2003 to contrast response of salmon between summer and winter, the magnitude of flow changes were greater (0.7–5.2 m3 s−1) and changes were made more rapidly (instantly). As discharge was increased, velocity and depth use by parr increased, and fish adapted behaviourally by increased contact with the substrate. Salmon parr also exhibited two distinct movement patterns in the summer and fall of 1999 studies; high site fidelity or considerable movement during trials. Salmon were more mobile during both static and dynamic flow conditions and throughout the diel cycle in the summer of 2002 experiment, and 2 fish were stranded and died, the only time this happened in the four series of experiments. Within each experiment generally there were no differences between movements at static high and low flows for day and night movements, with one exception, and night time movements were always greatest, again with one exception. During dynamic flow changes, within each experiment, distances moved during down ramping and up ramping were not significantly different except in the summer of 1999. Overall, comparing between experiments for up and down ramping events, distances moved in the summer of 2002 were statistically higher than for all other experiments. Not surprisingly, the home ranges of fish in the summer of 2002 were also the greatest while the smallest home ranges were in the winter of 2003. Results suggest hydropeaking regimes may be energetically costly potentially affecting over-winter survival which is related to energy reserves obtained during summer. Collectively these studies provide comprehensive information on the response of juvenile Atlantic salmon parr to hydropeaking, on both diel and seasonal scales, and will assist hydro producers and regulators design and operate hydropeaking regimes to minimize ecological impact.

A modular approach to simulation modelling offers significant advantages for its application to agricultural and environmental questions, including re-use of model equations in different contexts and with different user-interfaces; configuration of model structures that are most appropriate to a given problem; and facilitation of collaboration between modelling teams. This paper describes the Common Modelling Protocol (CMP), a generic, open and platform-independent framework for modular simulation modelling that is in widespread use. The CMP is distinguished from existing simulation frameworks by taking an explicitly hierarchical view of the biophysical system being simulated and by representing continuous and discontinuous processes equally naturally. Modules of model logic are represented in the CMP by entities known as “components”. Each component may possess “properties” that convey the value of the quantities in its equations and “event handlers” that compute model logic. Low-level information-transfers in the CMP are carried out by means of a message-passing system. Co-ordinated sequences of messages carry out tasks such as initialization, exchange of variable values and the control of computation order. Extensible Markup Language (XML) is used in the protocol for tasks such as denoting data types, submitting simulations for execution and describing components to user-interface software. Examples are presented showing how the CMP can be used to couple modules developed by different teams and to configure a complex model structure. The choices and trade-offs encountered when building a framework for modular simulation are analyzed, using the CMP and other simulation frameworks as examples. The kinds of scientific issues that arise when the CMP is used to realize collaboration between modelling groups are discussed.

Body-element content was measured for three life stages of wild Atlantic salmon Salmo salar from three distinct Newfoundland populations as individuals crossed between freshwater and marine ecosystems. Life stage explained most of the variation in observed body-element concentration whereas river of capture explained very little variation. Element composition of downstream migrating post-spawn adults (i.e. kelts) and juvenile smolts were similar and the composition of these two life stages strongly differed from adults migrating upstream to spawn. Low variation within life stages and across populations suggests that S. salar may exert rheostatic control of their body-element composition. Additionally, observed differences in trace element concentration between adults and other life stages were probably driven by the high carbon concentration in adults because abundant elements, such as carbon, can strongly influence the observed concentrations of less abundant elements. Thus, understanding variation among individuals in trace elements composition requires the measurement of more abundant elements. Changes in element concentration with ontogeny have important consequences the role of fishes in ecosystem nutrient cycling and should receive further attention.

Quantitative information regarding nitrogen (N) accumulation and its distribution to leaves, stems and grains under varying environmental and growth conditions are limited for chickpea (Cicer arietinum L.). The information is required for the development of crop growth models and also for assessment of the contribution of chickpea to N balances in cropping systems. Accordingly, these processes were quantified in chickpea under different environmental and growth conditions (still without water or N deficit) using four field experiments and 1325 N measurements. N concentration ([N]) in green leaves was 50 mg g-1 up to beginning of seed growth, and then it declined linearly to 30 mg g-1 at the end of seed growth phase. [N] in senesced leaves was 12 mg g-1. Stem [N] decreased from 30 mg g-1 early in the season to 8 mg g-1 in senesced stems at maturity. Pod [N] was constant (35 mg g-1), but grain [N] decreased from 60 mg g-1 early in seed growth to 43 mg g-1 at maturity. Total N accumulation ranged between 9 and 30 g m-2. N accumulation was closely linked to biomass accumulation until maturity. N accumulation efficiency (N accumulation relative to biomass accumulation) was 0.033 g g-1 where total biomass was -2 and during early growth period, but it decreased to 0.0176 g g-1 during the later growth period when total biomass was >218 g m-2. During vegetative growth (up to first-pod), 58% of N was partitioned to leaves and 42% to stems. Depending on growth conditions, 37-72% of leaf N and 12-56% of stem N was remobilized to the grains. The parameter estimates and functions obtained in this study can be used in chickpea simulation models to simulate N accumulation and distribution.

Quantitative information regarding leaf area development in chickpea (Cicer arietinum L.) is scarce. Data from four field experiments with a range of treatments including genotype, sowing date and plant density across four location-season combinations were analyzed to quantify main effects of temperature, photoperiod and plant population density on plant leaf area in chickpea. All experiments were conducted under well-watered conditions. Maximum rate of main stem node development was 0.72 nodes/d. Cardinal temperatures for node appearance were found as 6.0, 22.2 and 31.0 °C for base, optimum and ceiling temperatures, respectively. Plant density had no effect on cardinal temperatures for leaf appearance and phyllochron. Leaf senescence on the main stem started when the main stem had about 12 nodes and proceeded at a rate of 1.67% per each day increase in physiological day (a day with non-limiting temperature and photoperiod). Leaf production per plant versus main stem node number occurred in two phases; phase 1 when plant leaf number increased with a slower and density-independent rate (three leaves per node), and phase 2 with a higher and density-dependent rate of leaf production (8–15 leaves per node). A close relationship was found between the fraction of senesced leaves per plant and the same fraction on the main stem. The average leaf size per plant increased from 4 cm2 when there were 10 nodes on the main stem and stabilized at 10.8 cm2 when there were 21 nodes on the main stem. Plant density and sowing date did not affect leaf size. Plant leaf area was also predictable directly from main stem node number. The relationships found in this study can be used in simulation models of chickpea.

Quantitative information regarding biomass accumulation and partitioning in chickpea (Cicer arietinum L.) is limited or inconclusive. The objective of this study was to obtain baseline values for extinction coefficient (K), radiation use efficiency (RUE, g MJ) and biomass partitioning coefficients of chickpea crops grown under well-watered conditions. The stability of these parameters during the crop life cycle and under different environmental and growth conditions, caused by season and sowing date and density, were also evaluated. Two field experiments, each with three sowing dates and four plant densities, were conducted during 2002-2004. Crop leaf area index, light interception and crop biomass were measured between emergence and maturity. A K value of 0.5 was obtained. An average RUE of 1 g MJ was obtained. Plant density had no effect on RUE, but some effects of temperature were detected. There was no effect of solar radiation or vapour pressure deficit on RUE when RUE values were corrected for the effect of temperature. RUE was constant during the whole crop cycle. A biphasic pattern was found for biomass partitioning between leaves and stems before first-seed stage. At lower levels of total dry matter, 54 % of biomass produced was allocated to leaves, but at higher levels of total dry matter, i.e. under favourable and prolonged conditions for vegetative growth, this portion decreased to 28 %. During the period from first-pod to first-seed, 60 % of biomass produced went to stems, 27 % to pods and 13 % to leaves. During the period from first-seed to maturity, 83 % of biomass was partitioned to pods. It was concluded that using fixed partitioning coefficients after first-seed are not as effective as they are before this stage. Environmental conditions (temperature and solar radiation) and plant density did not affect partitioning of biomass.

Quantitative information on temperature and photoperiod effects on development rate in chickpea (Cicer arietinum L.) is scarce. Data from a serially sown field experiment (2001–2003) on four cultivars was used to evaluate various approaches to phenology prediction. A range of functions describing the response of development rate to temperature and photoperiod was compared. Phenological data from numerous other field experiments across Iran were used for independent model evaluation. A multiplicative model that included a dent-like function for response to temperature and quadratic function for response to photoperiod was the most adequate at describing the response of development rate to temperature and photoperiod. The differences among cultivars for cardinal temperatures and critical photoperiod were small and a base temperature of 0 °C, lower optimum temperature of 21 °C, upper optimum temperature of 32 °C, ceiling temperature of 40 °C and critical photoperiod (below which development rate decreases due to short photoperiods) of 21 h were obtained. Inherent maximum rate of development and the photoperiod sensitivity coefficient characterized cultivar differences. The cultivars required 24.7–32.2 physiological days (i.e., number of days under optimum temperature and photoperiod conditions) from emergence to flowering, 8.2–12.0 from flowering to first-pod, 4.3 from first-pod to beginning seed growth and 30.3 from beginning seed growth to maturity. Differences among cultivars were not found for first-pod to beginning seed growth or for beginning seed growth to maturity. The phenology model developed using these findings gave good predictions of phenological development for a diverse range of temperature and photoperiod conditions across Iran. This model can be incorporated in simulation models of chickpea.

Quantitative information about temperature and sowing depth effects on seedling emergence in chickpea (Cicer arietinum L.) is scarce. The main objective of this study was to develop a seedling emergence model for chickpea. To do this, a field experiment with a range of sowing dates and a pot experiment were conducted to determine cardinal temperatures and physiological days (i.e., number of days under optimum temperatures) required for seedling emergence, and to quantify the response of seedling emergence to sowing depth. In the field experiment, four chickpea cultivars were sown at 11 dates and time to emergence and emergence percentage were evaluated. Sowing depth was 5 cm. Several linear and non-linear functions were used to describe the relationship between emergence rate and temperature. The pot experiment was conducted in a controlled-temperature room (21 ± 1 °C) using five sowing depths (2.5-14 cm). Results showed that the response of chickpea emergence to temperature is best described by a dent-like function with cardinal temperatures of 4.5 °C for base, 20.2 °C for lower optimum, 29.3 °C for upper optimum and 40 °C for ceiling temperature. Six physiological days (equivalent to a thermal time of 94 °C days) was required from sowing to emergence at a sowing depth of 5 cm. The physiological days requirement increased by 0.9 days for each centimetre increase in sowing depth. Based on the results from the field and pot experiments, a seedling emergence model was constructed. This model successfully simulated emergence date (range 4-140 days) in spring, winter and 'dormant' sowing dates across Iran. Using an example for North West Iran, it was shown how this model could be used to optimise sowing management, including the local 'dormant sowing' practice, whereby the crop is sown prior to winter for early emergence in the following spring.

Variable hydropower production leads to hydropeaking, which causes discharge fluctuations that are potentially harmful to aquatic organisms. In this study, an experimental approach was used to investigate hydropeaking effects and associated hydraulic and habitat conditions on the home range and movement of juvenile Atlantic salmon Salmo salar. Prior studies examined the responses of Atlantic salmon and brook trout Salvelinus fontinalis to experimental hydropeaking during summer and autumn. The present study focused on Atlantic salmon, involved more rapid and extreme discharge manipulation, and included winter experiments to reflect influences of reduced temperature, ice conditions, and seasonal differences in behavior and habitat selection. Experiments were conducted over a range in discharge (0.5–5.0 m3/s) that resulted in dramatic habitat changes in the wide, shallow, boulder-strewn study reach. Experiments were repeated in summer and winter; however, the winter range in discharge was narrower ...

In Australian sugarcane crops, growth in terms of radiation use efficiency (RUE) can appear to slow down well before final crops are harvested, despite conditions that are considered favourable for growth. In order to assess the extent and cause of this reduced growth phenomenon (RGP), 14 experiments conducted in Australia were examined. From these experiments, 34 treatments were selected where nutrients and water were likely to be non-limiting and consequently the yields obtained were likely to be limited only by temperature and radiation. Radiation use efficiency is defined as the measured amount of net biomass accumulated above ground per unit radiation intercepted. Accumulated biomass may have been lost through loss of stalks. In almost half of the treatments RUE significantly declined between approximately 223 and 665 days after crop start. The high incidence of RGP found in the analyses (a) challenges the previously held assumption that a constant value of RUE can be used to adequately describe biomass accumulation in sugarcane as a function of cumulative radiation interception and (b) suggests that relatively low growth rates during the later phases of the cropping season are frequently experienced throughout the Australian sugar industry. Reduced growth phenomenon resulted in actual biomass at final harvest being on average 21% less than potential yield, compared with 5% in crops that did not display a slowdown in growth. Mean maximum RUE in the plant crop was greater than in ratoon crops, at 1.37 and 1.19 g MJ −1 , respectively. As there was no effect of location, cultivar, crop duration, ratoon crop class or fumigation treatment on RUE for the periods either before or after the onset of reduced growth, it would appear that the value of RUE is predominantly influenced by crop class. Despite the differences in RUE between the two crop classes, RGP occurred at a similar frequency in both plant and ratoon crops. In order to gain a greater mechanistic understanding of the factors likely to be associated with the onset of the RGP, the relative time of lodging, specific leaf nitrogen (SLN), number of stalks and seasonal temperature were all considered individually. Whilst declining SLN and increasing stalk loss were associated with reductions in growth during the later periods of crop growth, it is likely that lodging also contributed to the widespread slowdown in biomass accumulation, whereas photosynthetic stress, as a result of extreme temperatures, did not play a substantive role in reducing growth.

International sugarcane farming practice has been significantly influenced by crop physiology research, both directly, and indirectly via process-based, simulation growth models. These models not only operationalise our basic physiology understanding but also serve to identify knowledge gaps and priority research areas. This paper explores the integration between basic field research, model development and application and on-ground impact. It explores the historical mutual dependency between basic sugarcane physiology research and model development through a brief summary of the key sugarcane models and the seminal published field and controlled-environment studies on which they are based. Examples are given of applications of this understanding and modelling capability that have led to, or have the potential to lead to, significant impacts on sugarcane farming system design, practice and policy. These include the benchmarking of potential yields to guide industry expansion, marketing and to optimize management practice; the scheduling of irrigation practice; analysis of the likely risks and benefits of investment in on-farm water storages and the subsequent identification of best-bet designs; and the forecasting of crop yields via integration with climate forecasting tools. Examples are also given of the combined use of field experimentation and modelling to dispel and/or clarify historical rules of thumb/folklore. Finally, the paper identifies current gaps in our understanding of sugarcane physiology and the potential applications and impacts to be gained from an improved understanding in these areas. These include; an enhanced understanding of the ageing process, sucrose accumulation, water stress physiology and the physiology of water retention in stalks.

A velvet bean (Mucuna pruriens L.) module for the agricultural production systems simulator (APSIM) was developed in order to assess the nitrogen (N) and yield benefits of velvet bean green manure crops, when grown in rotation with maize in small holder situations in Malawi. The velvet bean module was able to simulate maturity biomass from six contrasting sites in Malawi over an observed range of 847–10,420 kg/ha with a root mean squared deviation (RMSD) of 1562 kg/ha. APSIM was then tested for its ability to simulate the response of maize crops to fertiliser N in two seasons, to previous velvet bean green manure crops in one season, or both in combination in one season. With no previous velvet bean crop, the response to fertiliser N varied across sites from a non-significant increase to an eight-fold increase in maize yield. Where a velvet bean crop was grown in the previous season, the response to applied N varied from non-significant to slight. Simulated yields were within one standard error of the observed in the majority of cases. A sensitivity analysis for key parameters in the velvet bean module highlighted, that those governing the N content of crop root and shoot residues had greatest impact on maize yield response. Parameters controlling production and partitioning of root or shoot biomass were less important. To our knowledge this is the first reported case of a cropping systems simulation model being tested for its ability to simulate the production of a green manure legume followed by a cereal.

The effect of increased flow on movement and microhabitat use of Atlantic salmon Salmo salar parr in winter was investigated using radiotelemetry. To simulate hydropeaking operations, flow was increased four-fold from 1.3 m 3 s -1 to 5.2 m 3 s -1 for 24 h periods. Flow did not affect fish habitat use or displacement and had little effect on fish activity within diel periods. During high flow periods in late winter, fish reduced night-time activity. Stranding rates during flow reduction were also Very low (only one fish).

Mungbean (Vigna radiata L.), as a dryland grain legume, is exposed to varying timing and severity of water deficit, which results in variability in grain yield, nitrogen accumulation and grain quality. In this field study, mungbean crops were exposed to varying timing and severity of water deficit in order to examine: (1) contribution of the second flush of pods to final grain yield with variable timing of relief from water deficit, (2) the sensitivity to water deficit of the accumulation of biomass and nitrogen (N) and its partitioning to grain, and (3) how the timing of water deficit affects the pattern of harvest index (HI) increase through pod filling. The results showed that the contribution of the second flush to final yield is highly variable (1-56%) and can be considerable, especially where mid-season stress is relieved at early pod filling. The capacity to produce a second flush of pods did not compensate fully for yield reduction due to water stress. Relief from mid-season stress also resulted in continued leaf production, N-2 fixation and vegetative biomass accumulation during pod filling. Despite the wide variation in the degree of change in vegetative biomass and N during pod filling, there were strong relationships between grain yield and net-above-ground biomass at maturity, and grain N and above-ground N at maturity. Only in the extreme situations were HI and nitrogen HI affected noticeably. In those treatments where there was a large second flush of pods, there was a pronounced biphasic pattern to pod number production, with HI also progressing through two distinct phases of increase separated by a plateau. The proportion of grain yield contributed to by biomass produced before pod filling varied from 0 to 61% with the contribution greatest under terminal water deficit. There was a larger effect of water deficit on N accumulation, and hence N-2 fixation, than on biomass accumulation. The study confirmed the applicability of a number of long-standing physiological concepts to the analysis of the effect of water deficit on mungbean, but also highlighted the difficulty of accounting for timing effects of water deficit where second flushes of pods alter canopy development, biomass and yield accumulation, and N dynamics. Crown Copyright (C) 2003 Published by Elsevier B.V. All rights reserved.

Radio-telemetry was used to investigate movement of large, mainly mature male (80%) Atlantic salmon Salmo salar parr in Stoney River, Newfoundland during early winter (November; water temperature 6·0 ± 0·1° C) and mid-winter (January to February; 0·8 ± 0·0° C). Site fidelity of parr in early winter was low. Parr moved between fluvial and lacustrine habitats and were active throughout the diel cycle. Parr caught in fluvial habitats in mid-winter were smaller and younger than parr caught in early winter. Site fidelity of parr in mid-winter was greater than in early winter. Parr in mid-winter moved between fluvial and adjacent small lacustrine habitats, but avoided a larger pond inhabited by large piscivorous fishes. Instream movement rates in mid-winter were lower than in early winter and occurred primarily during hours of darkness (dawn, dusk and night). Fluvial habitats were relatively stable and ice-free throughout the study periods. These results suggested that large Atlantic salmon parr utilize a variety of habitats and remain active throughout the winter, even under stable environmental conditions.

Experiments were conducted on wild Atlantic salmon Salmo salar parr to determine the effect of surgically implanted dummy transmitters on swimming performance, food consumption and growth. Swimming performance of tagged fish (tag 1·7–3·7% of fish mass) was similar to that of control fish 1, 5 and 10 days after surgery. Negative effects on growth, however, were found up to day 36 of a 45 day experiment (tag 0·9–2·6% of fish mass). Consumption rates were similar between tagged and control fish and did not explain differences in growth.

The Agricultural Production Systems Simulator (APSIM) is a modular modelling framework that has been developed by the Agricultural Production Systems Research Unit in Australia. APSIM was developed to simulate biophysical process in farming systems, in particular where there is interest in the economic and ecological outcomes of management practice in the face of climatic risk. The paper outlines APSIM's structure and provides details of the concepts behind the different plant, soil and management modules. These modules include a diverse range of crops, pastures and trees, soil processes including water balance, N and P transformations, soil pH, erosion and a full range of management controls. Reports of APSIM testing in a diverse range of systems and environments are summarised. An example of model performance in a long-term cropping systems trial is provided. APSIM has been used in a broad range of applications, including support for on-farm decision making, farming systems design for production or resource management objectives, assessment of the value of seasonal climate forecasting, analysis of supply chain issues in agribusiness activities, development of waste management guidelines, risk assessment for government policy making and as a guide to research and education activity. An extensive citation list for these model testing and application studies is provided.

The Agricultural Production Systems slMulator, APSIM, is a cropping system modelling environment that simulates the dynamics of soil-plant-management interactions within a single crop or a cropping system. Adaptation of previously developed crop models has resulted in multiple crop modules in APSIM, which have low scientific transparency and code efficiency. A generic crop model template (GCROP) has been developed to capture unifying physiological principles across crops (plant types) and to provide modular and efficient code for crop modelling. It comprises a standard crop interface to the APSIM engine, a generic crop model structure, a crop process library, and well-structured crop parameter files. The process library contains the major science underpinning the crop models and incorporates generic routines based on physiological principles for growth and development processes that are common across crops. It allows APSIM to simulate different crops using the same set of computer code. The generic model structure and parameter files provide an easy way to test, modify, exchange and compare modelling approaches at process level without necessitating changes in the code. The standard interface generalises the model inputs and outputs, and utilises a standard protocol to communicate with other APSIM modules through the APSIM engine. The crop template serves as a convenient means to test new insights and compare approaches to component modelling, while maintaining a focus on predictive capability. This paper describes and discusses the scientific basis, the design, implementation and future development of the crop template in APSIM. On this basis, we argue that the combination of good software engineering with sound crop science can enhance the rate of advance in crop modelling. Crown Copyright (C) 2002 Published by Elsevier Science B.V. All rights reserved.

FARMSCAPE (Farmers', Advisers', Researchers', Monitoring, Simulation, Communication And Performance Evaluation) is a program of participatory research with the farming community of northeast Australia. It initially involved research to explore whether farmers and their advisers could gain benefit from tools such as soil characterisation and sampling, climate forecasts and, in particular, simulation modelling. Its current focus is facilitating the implementation of commercial delivery systems for these same tools in order to meet industry demand for their access. This paper presents the story of what was done over the past decade, it provides performance indicators of impact, it reflects on what was learnt over this period and it outlines where this research is likely to head in the future. Over the past 10 years, the FARMSCAPE team employed a Participatory Action Research approach to explore whether farmers could value simulation as a decision support tool for managing their farming system and if so, could it be delivered cost-effectively. Through farmer group engagement, on-farm trials, soil characterisation, monitoring of crops, soils and climate, and sessions to apply the APSIM systems simulator, FARMSCAPE represented a research program on decision support intervention. Initial scepticism by farmers and commercial consultants about the value of APSIM was addressed by testing its performance both against measured data from on-farm trials and against farmers' experiences with past commercial crops. Once this credibility check was passed, simulation sessions usually evolved into participants interactively inquiring of the model the consequence of alternative management options. These ‘What if’ questions using APSIM were contextualised using local climate and soil data and the farmer's actual or proposed management rules. The active participation of farmers and their advisers, and working in the context of their own farming operations, were the key ingredients in the design, implementation and interpretation of the FARMSCAPE approach to decision support. The attraction of the APSIM systems simulator to farmers contemplating change was that it allowed them to explore their own system in a manner equivalent to learning from experience. To achieve this, APSIM had to be credible and flexible. While direct engagement of farmers initially enabled only a limited number of beneficiaries, this approach generated a commercial market for timely and high quality interactions based on soil monitoring and simulation amongst a significant sector of the farming community. Current efforts are therefore focused on the training, support and accreditation of commercial agronomists in the application of the FARMSCAPE approach and tools. The FARMSCAPE approach to decision support has come to represent an approach to guiding science-based engagement with farm decision making which is being tested nationally and internationally.

Partitioning of dry matter (DM) in sugarcane is of interest for two fundamental reasons. Firstly, sugar production depends directly on partitioning of crop biomass to the stalk and then to sucrose stored largely in stalk parenchyma. Secondly, various DM components of the stalk and particularly sucrose concentration are used to calculate the value of cane consignments delivered to the mill. In this study we review data from serial harvesting experiments in South Africa and Australia to discover similarities and differences in DM partitioning of sugarcane grown in a wide range of conditions and to gain a better understanding of the factors influencing DM partitioning as a basis for improving functional responses in sugarcane simulation models. Firstly, climatic and genetic variations in DM partitioning to various above ground plant components of sugarcane and to sucrose within the stalk component, are examined at a broad level. We then assess the robustness of sucrose partitioning rules used in the two international sugarcane models (APSIM and CANEGRO) and provide enhancements on predictions of sucrose content (SC) on a DM basis in sugarcane stalks. Well-adapted cultivars in widely different climatic conditions were similar with respect to partitioning of biomass to various above ground organs. The trash component (dead leaves and dead stalks) was one that varied most between cultivars and growing conditions. The stalk fraction of green biomass (biomass less trash) reached a maximum of about 0.85 when green biomass yield exceeded 60 t ha −1 regardless of cultivar or extremes of water regime. Opportunities for further improvements of this trait through breeding were not obvious but harvesting could be delayed to ensure that stalk fraction is as high as possible. Variations in SC with respect to age, biomass and seasonal variation in climate, were explained by a simple conceptual model of cane stalk segments which are rapidly filled with sucrose when young and may remobilise sucrose when carbohydrate is required for rapid expansive growth. Season and age effects on whole stalk SC are due to varying proportions of young segments with low SC and older segments with high SC. A mechanistic model capturing these concepts is required but as an interim measure an empirical model based on stalk mass, leaf number per stalk, leaf area index and temperature accounted for a large proportion of the variation in SC across Australian and South African cultivars and conditions. Uses for this model together with CANEGRO or APSIM include improved SC through manipulating irrigation and the harvest schedule and more realistic targets for cane quality.

Data from a long-term trial on rates of fertilizer nitrogen (N) application to maize (Zea mays) were used to validate a cropping systems simulation model (APSIM) and then to apply the model to explore the risk associated with N fertilizer use by smallholder farmers and management strategies to minimize that risk. On average, maize growth and development in response to N was simulated with a degree of accuracy that justified its use in analysis of risk associated with N use in these semi-arid regions of Zimbabwe. APSIM was then configured to simulate the response to N over a 46-year climate record in order to assess the long-term risks associated with N use. The simulated long-term distribution indicated that negative responses to N could be expected in 15% of years, whereas no negative response to N was recorded in the experiments at the Makoholi Research Centre. Median responses were 20–30 kg maize grain kg−1 N for observed and simulated results. In terms of return on fertilizer investment, the observed and simulated distributions were also similar: in about 20% of years, a negative return could be expected, while in the best 20% of years a return of $Z5000 or more could be expected given the grain:fertilizer price ratio which, at March 2000, was about 1:7. The model analysis has suggested moderate rates (approximately 30 kg N ha−1) of N fertilizer would give greater responses per unit N applied than smaller rates (15 kg N ha−1). There was no evidence that conditional fertilizer strategies based on early-season rainfall would offer significant benefits over fixed application strategies. Early sowing at recommended population densities gave higher responses to N than were achieved for late sown or low-density crops.

There are very sparse data on the outcomes of children receiving prolonged extracorporeal membrane oxygenation (ECMO) after cardiac surgery. This study was aimed to evaluate the association of ECMO duration with outcomes in children undergoing surgery for congenital heart disease using the Pediatric Health Information System (PHIS) database.Patients aged ≤18 years receiving ECMO after pediatric cardiac surgery (with or without cardiopulmonary bypass) at a PHIS-participating hospital (2004-2013) were included. De-identified data obtained from retrospective, observational dataset included demographic information, baseline characteristics, pre-ECMO risk factors, operation details, patient diagnoses, and center data. Outcomes evaluated included in-hospital mortality, length of mechanical ventilation, length of ICU stay, length of hospital stay, and hospital charges. Cox proportional hazards models were fitted to study the probability of study outcomes as a function of ECMO duration.Nine hundred ninety-eight patients from 37 hospitals qualified for inclusion. The median duration of ECMO run was 4 days (IQR: 1.7). After adjusting for patient and center characteristics, there was 12% increase in the odds of mortality for every 24 hours increase in ECMO duration (OR: 1.12, 95% CI: 1.07-1.18, P0.001). Patients receiving longer duration of ECMO were associated with longer length of mechanical ventilation, longer length of ICU stay, longer length of hospital stay, and higher hospital charges.Data from this large multicenter database suggest that longer duration of ECMO support after pediatric cardiac surgery is associated with worsening outcomes.

A simulation model of pigeonpea is described that is designed to simulate the development, growth, nitrogen accumulation and yield of a wide range of maturity types from extra-short to medium-duration in response to weather, soil conditions and agronomic management. Parameters of the model for phenological development, leaf area expansion, radiation interception, biomass accumulation and partitioning, crop water use, root growth and water extraction, and nitrogen accumulation are derived from published studies. In addition, the calibration exercise is described to derive the parameters accounting for the effect of plant population density on leaf area expansion. The model was tested on 38 data sets, not previously used to derive model parameters, collected at Patancheru, India. Data sets encompassed a wide range of plant type, sowing density, and seasons, grown on alfisol and vertisol soil types under dryland and irrigated conditions. The time to flowering and maturity from the extra-short to medium-duration types were simulated well, explaining 96 and 92% of the variance (RMSD=4.3 and 9.8 days), respectively. Total aboveground biomass was simulated with less accuracy, explaining 74% of the variance ( RMSD =2056 kg ha −1 ) and grain yield was simulated explaining 76% of the variance ( RMSD =332 kg ha −1 ) . There remains scope for model improvement in the areas of waterlogging and testing on crop N accumulation. This pigeonpea module, when coupled with other crop, soil and management modules can be used to address a range of cropping systems issues.

Examining physiological relationships that quantify the processes of interception of radiation and biomass accumulation and partitioning provide one avenue for understanding limits to pigeon pea productivity. The radiation extinction coefficient (k), radiation use efficiency (RUE), partitioning of biomass between leaf and stem before flowering, and the rate of linear increase in harvest index (HI) during pod-filling were determined for nine cultivars in water and nutrient non-limiting conditions at ICRISAT Centre, Patancheru, Andhra Pradesh, India. The nine cultivars comprised three each from the cultivar duration classes extra-short (100 days to maturity), short (115 days) and medium (170 days). Values of k and RUE were consistent across duration groups, with mean values of 0.53 and ca. 0.9 g MJ-1, respectively. RUE remained at its maximum value almost until maturity. Partitioning between leaf and stem prior to flowering was also consistent across groups, in the ratio of 1:1.03 to 1:1.14. The rate of linear increase in HI and final HI varied across groups, with lower rates of partitioning to grain and final HI in the later maturing groups. When adjusted for fallen leaf, the HI increase was ca. 0.08, 0.075 and 0.04 per day, and maximum HI was ca. 0.35, 0.32 and 0.19 for extra-short, short and medium-duration groups, respectively. The association of lower HI increase with indeterminate growth provides a convenient framework to simulate concurrent reproductive and vegetative growth during pod-filling.

Data from sowing-date and other experiments conducted for nine cultivars at three locations ranging from 1°30′S to 27°15′N were analysed for photoperiod response. All cultivars were found to have a qualitative response to photoperiod. The results of the analysis show that cultivars previously reported to be “relatively insensitive” to photoperiod were, in fact, highly sensitive. Flowering in short-duration cultivars was delayed by up to a 100 days when daylength in the photoperiod-inductive phase exceeded a critical value. Medium- and long-duration cultivars delayed flowering by over 150 days in response to photoperiod. A model was able to predict this wide range in flowering dates.

Relationships are developed that describe the processes of node production, leaf appearance and senescence, and leaf size in pigeonpea in relation to temperature, plant density and maturity type. The rate of node production until flowering in relation to thermal time was found to be unaffected by season and plant density in the range of 4–33 plants m −2 . Maturity type did not affect the rate of node production on the main stem or the rate of appearance of leaves on the plant. The rate of senescence of main-stem nodes in relation to thermal time was unaffected by plant density and growth duration. The functions developed in this paper can be used to predict the temporal changes in leaf area development in crop growth models.

This paper demonstrates the capability of the model, APSIM-Sugarcane to analyse system performance, by consideration of crop production and related issues for two contrasting sugarcane production systems in northern Australia. Daily output data from short-term model runs are used to demonstrate the capability of the model to represent the diverse management of sugarcane crops encountered in Australia. Output from longer term simulations is used to investigate a number of ‘real life’ sustainability issues, including an assessment of the production risk associated with season to season climate variability at each site, and the long-term implications of crop residue management on system performance. The paper also develops guidelines for methodological issues in long-term simulations of sugarcane production systems, relating to (1) the length of the climate record necessary to capture the ‘true’ season to season variability, (2) the need or otherwise to simulate each crop class (i.e. plant and ratoon crops) over the full climate record, and (3) the impact of initial soil conditions on the time for the system to reach a state of equilibrium. Results from statistical tests comparing pairs of distributions for various simulation run lengths, identified significant differences for run lengths up to 40 years. This suggests that, while adequate for most scenarios, the current practice of basing sugarcane simulations on 40 years’ climate data will not always capture the true season to season variability in response to climate. Results showed that variability associated with season to season climate by management interactions can be adequately captured in a single model run comprised of consecutive crop cycles, without the need to represent every crop class in every year. These findings have the potential to significantly improve modelling efficiency by reducing model run times, simplifying the analysis of model output and, reducing the required computer storage space. Results from long-term simulations, for some model output variables, indicate there is likely to be an initial period of ‘settling in’ of between 5 and 10 years as the model approaches a state of equilibrium, during which the response of certain model variables will be ‘abnormal’ and should be used with caution or discarded.

The Mauritian sugar cane ( Saccharum spp.) industry is characterised by high climatic variability both from year-to-year and across agro-climatic zones. There is a need to assess yield variation with a view to facilitate crop management as well as investment decision-making, such as irrigation schemes. The aim of this study is to assess the feasibility of using crop simulation modelling to quantify potential and attainable yield at contrasting sites. Potential yield is that limited by temperature, radiation, for a given cultivar and season length, while attainable yield has the additional constraint of water supply (rainfall and irrigation where it is applied). The sugar cane module of the Agricultural Productions Systems Simulator (APSIM-Sugar cane) had not been previously used under Mauritian conditions. Hence, the first step is to validate the model using data from growth analysis experiments with plant and ratoon crops of three contrasting commercial cultivar (R 570, M 13/56 and M 555/60), harvested at two dates (July and October) at two sites. The validation step showed that only a limited number of crop coefficients needed adjustment: those concerning canopy expansion, biomass partitioning and crop development. Linear fit of simulated and observed data were close to the 1:1 line and coefficients of determination were highly significant for LAI ( r 2 =0.66), above-ground biomass ( r 2 =0.84), dry weight of cane ( r 2 =0.73) and sucrose yield ( r 2 =0.78). There was some indication that model modification for the effects of water stress and flowering on canopy development and biomass accumulation would improve the simulations The model was used to assess the variability in potential and attainable yield at three sites (Pamplemousses, Medine and Reduit) using long-term climate data for the period 1961–1995. Simulations were conducted for rainfed and fully irrigated scenarios. The three sites contrasted in annual rainfall, solar radiation and mean temperature and hence in expected potential and attainable yield. The range in model-simulated yields of cultivar R 570 were close to the range of experimentally observed yields at the selected sites under rainfed and fully irrigated conditions. Simulated yields were more variable under rainfed than irrigated production, with variability increasing across sites as mean annual rainfall decreased. Under rainfed production, yield was poorly correlated with annual rainfall at all sites. At all sites, irrigated yields across the climatic record were highly positively correlated with mean daily solar radiation. The study showed that it is feasible to import a pre-existing model, parameterise it for local cultivars and conduct scenario analysis.

An analysis of the physiological consequences of water deficit during the first half of the season on sugarcane productivity, can aid the evaluation of yield expectations under rainfed systems and the opportunities for saving irrigation water early in the season. Four field experiments were conducted at Ayr in the semi-arid tropics of Australia. Irrigation was withheld at different stages of crop development to investigate timing and severity of water deficit on crop development, biomass accumulation and partitioning of biomass to millable stalk and sucrose, both during the season and at final harvest. Deficits imposed during the tillering phase, while having large impacts on leaf area, tillering and biomass accumulation, had little impact on final yield. This was primarily due to the length of time required to impose significant water deficit when the canopy is small, the comparatively small amount of biomass accumulation lost through water deficit, and the ability of the crop to produce leaves and tillers at a rapid rate during subsequent well-watered conditions. On the other hand, water deficit imposed when the canopy was well-established (leaf area index >2) had a more deleterious impact on final yield of total biomass, stalk biomass, and stalk sucrose. Reductions in millable stalk biomass, could be solely explained by reductions in total biomass. Similarly, >97% of the variation in final cane or sucrose yield could be explained by variation in stalk biomass. While there were transient effects of water deficit on stalk sucrose and dry matter concentration, significant impacts at final harvest did not occur until stalk biomass levels fell to ca. 50% of that of the well-watered control.

Research on more productive and sustainable sugarcane production systems would be aided by a comprehensive simulator of the sugarcane crop that is cognisant of a broader crop-soil-management system. A sugarcane crop model is described that can be deployed in the APSIM framework for agricultural systems simulation. The model operates on a daily time step, grows a leaf canopy, uses intercepted radiation to produce assimilate, and partitions this assimilate into leaf, structural stalk and sugar. The crop physiological processes represented in the model respond to the radiation and temperature environment and are sensitive to water and nitrogen supply. The model simulates growth, water use, N accumulation, sugar dry weight and fresh cane yield for plant and ratoon crops in response to climate, soil, management and genotypic factors. The model was developed on 35 datasets from Australia, Hawaii, South Africa and Swaziland, covering a wide range of crop classes, latitudes, water regimes and nitrogen supply conditions. Coefficients of determination for model predictions compared to observed data included 0.79 for LAI, 0.93 for crop biomass, 0.83 for stalk sucrose and 0.86 for N accumulation in above ground tissues. The particular strengths of this model are discussed in the context of agricultural systems simulation.

In irrigated sugarcane production, water is usually withheld prior to harvest to dry the field and to raise the sucrose content of the cane. Past research has provided conflicting results on the optimum length of drying-off. An analysis was conducted of pooled data from 37 experiments on drying-off in Southern Africa to: (1) determine the range of responses in sucrose yield and cane sucrose concentration that have been attained under various drying-off regimes; (2) quantify the trade-off between the loss in cane yield under drying-off and any possible gain in sucrose yield and cane sucrose fresh weight (FW) concentration; and (3) identify which components of sucrose yield and sucrose concentration are most sensitive to late-season water deficit, as a means of developing functions for crop simulation models. In only 22% and 61% of the drying-off treatments was there a significant increase in sucrose yield or sucrose FW concentration, respectively. For both sucrose yield and sucrose FW concentration, the average increase attained by drying-off was 8% and the maximum increase was about 15%. Increase in sucrose yield occurred when the decrease in stalk dry mass was no greater than about 10%. This relationship could form the basis for determining the trade-off between reduction in stalk mass and sucrose yield under varying drying-off regimes, and developing economic optima for drying-off severity. Increase in sucrose FW concentration occurred due to an increase in soluble solids and dehydration. Small reductions in fresh yield of cane under drying-off (up to 10%) can be attributed equally to dehydration and reduction in stalk dry mass.

Blue green vertical cavity surface emitting lasers (VCSELs) have been produced in which the active region comprised molecular beam epitaxy (MBE) grown ZnSe layers containing one or more ZnCdSe quantum wells. As a first step towards the production of a workable VCSEL we have produced optically pumped structures which have allowed us to address a number of issues relating to the design of the devices and the reproducibility of the grown active layers. In this paper we discuss those factors which are specific to II–VI compounds relating to the design, growth and fabrication of optically pumped blue green VCSELs, with the emphasis on overcoming problems in producing practical devices. We have demonstrated that with careful control of the growth conditions we have been able to grow structures in which the predicted and measured spontaneous emission peaks differed by only 1%, leading to the growth of VCSEL structures with less than 3% misalignment in the gain and cavity resonances. © 1998 Chapman & Hall

Root growth and soil water content were measured in a field experiment with wheat subjected to two periods of water deficit. The first period was induced early in the season between the early vegetative stage (22 DAS) and late terminal spikelet (50 DAS), the second period at mid-season between terminal spikelet (42 DAS) and anthesis (74 DAS). Total root growth was reduced under water deficit by a reduction in the top 30 cm, while the root system continued to grow in the deeper soil profile between 30 and 60 cm. Shortly after rewatering, the growth pattern reverted to fastest root growth rates in the shallow soil layers. In relative terms, the total root system increased in relation to the above ground dry matter under water shortage. The early-, the mid-season water deficit treatments, and the control treatment had total root length of 27.4, 19.4 and 30.6 km m-2, respectively, about 2 wk before maturity. Evapotranspiration declined under water deficit, but water uptake in deeper layers increased. Water uptake per unit root length was reduced with water deficit and was still low shortly after rewatering. Remarkable was the increase in water uptake at 2–3 weeks after rewatering, both deficit treatments exceeded the control by almost 100%. This increase in water uptake followed the burst of new root growth in the upper regions of the soil. However, water uptake rates subsequently declined towards maturity, being between 0.15 L km-1 d-1 and 0.17 L km-1 d-1 for the early and mid-season water deficit treatments, slightly higher than the control, 0.12 L km-1 d-1. The results showed that the crop subjected to early water deficit could compensate for some of the reductions in root growth during subsequent rewatering, but the impact of the mid-season water deficit treatment was more severe and permanent.

CD94 (Kp43) is a member of the human C-type lectin superfamily encoding type II membrane glycoproteins expressed on NK cells and a subset of T cells. Ligation of CD94 has been shown to either potentiate or inhibit NK cell proliferation and cytolytic effector function. Here we show that CD94 ligation triggers apoptosis in IL-2-primed NK cells. Evidence for CD94-induced apoptosis includes: 1) chromatin condensation as measured by increased fluorescence of Hoechst dye, 2) induction of DNA fragmentation, and 3) characteristic morphology by transmission electron microscopy. IL-2 priming (at least 12 h) is required for activation-induced NK cell death triggered by CD94. Activation-induced NK cell death triggered by CD94 ligation is extremely rapid (DNA fragmentation is first observed at 120 min). Unlike activation-induced T cell death, it is not inhibited by neutralizing Abs reactive with TNF-alpha or Fas ligand. Our results suggest that CD94 may play a role in the elimination of activated NK cells during the transition from the innate to the Ag-specific immune response.

Sugarcane was grown under full irrigation in Australia, South Africa and Hawaii. N fertiliser was supplied at a high rate and was non-limiting to biomass accumulation in all but one dataset, where zero and high nitrogen (N) supply regimes were imposed. Crops were sampled for biomass, sucrose, glucose and fructose content of stalks. In one study, the biomass and sugar content of all green crop components were also determined. The objective was to compare the accumulation of reducing sugars, glucose and fructose, with sucrose, and how this responds to agronomic manipulations of crop duration, cultivar and nitrogen supply. Such knowledge can be used to assess the scope for maximising, by agronomic or genetic means, the partitioning of biomass to the economic product, sucrose and maximising the purity of juice for efficient sucrose extraction at the mill. At 12 months growth, 30–50% of reducing sugars was present in the stalk component, but at earlier stages was higher at 50–80%. Stalk yields of reducing sugars for 12 month crops were less than 100 g m−2, which was less than 5% of total sugars in the stalk. There were strong effects of N supply and cultivar on the amounts and concentration of reducing sugars in the stalk at low yields, but little effect when stalk biomass exceeded about 4000 g m−2 suggesting that, agronomic or genetic manipulation of levels of reducing sugars will only be effective early in the season. For a given level of stalk biomass, cultivar effects on partitioning to reducing sugars were due either to differences in partitioning of stalk biomass to total sugars, or differences in the partitioning between sucrose and reducing sugars. On the other hand, variation in N supply only altered the partitioning between sucrose and reducing sugars. Calculations suggested that high concentrations of reducing sugars in stalks harvested at a young age or from high N supply treatments, were not expected to lower the polarimetric estimate of sucrose concentration in the juice by more than 6%. This study provides a framework to assess the impact of cultivar, crop duration, and N supply on the accumulation of reducing sugars in different production systems.

Leaf nitrogen (g N m−2 leaf) is an important determinant of crop radiation-use efficiency. It is not known to what extent sugarcane can maintain high leaf N over its long growth duration. This study analyses the accumulation of N in two contrasting cultivars of sugarcane (Q117, Q138) under plant and ratoon crop conditions, and the partitioning of N to the various plant components, including the leaf. The crops were grown for 15 months under irrigated conditions in the same season and received 34.4 g N m−2 as fertiliser over the first 100–120 days of the season. Higher early N accumulation by the ratoon crop was associated with higher early biomass production. However, maximum N accumulation was unrelated to maximum biomass accumulation, with the plant crop (25.9 g N m−2) accumulating more than the ratoon crop (21.3 g N m−2), which resulted in widely varying values for biomass/N ratio. N accumulation ceased later in the plant (200 days) than in the ratoon (150 days) crop, and this occurred 100–140 days before maximum biomass. More work is needed to determine if this is due to exhaustion of soil N supply, reduced root activity, or a lowered crop N requirement. Leaf N was maintained above 1.2 g N m−2 for 300 days of the 450 day season. Decline in leaf N below 1.2 g N m−2 at the end of the season was associated with loss in leaf and total crop N accumulation, and apparently unrelated to the timing of cessation in biomass accumulation. Throughout the season, leaf N was higher in the plant than the ratoon crop (averaged over cultivars), and Q117 versus Q138 (averaged over crop classes), however these differences could not explain crop-class differences in RUE. Cultivar differences in leaf N were due to higher N accumulation because specific leaf area and partitioning of biomass and N to leaf were unaffected by crop class or cultivar. The biomass/N ratio varied with cultivar and crop class, and increased with crop age.

Information on the processes controlling the accumulation of sucrose over time can be used to assess the physiological basis of yield variation and consequently the scope for yield improvement in sugarcane. As commercial yield is commonly expressed on a fresh weight basis, and dry weight measures of sucrose accumulation aid biological interpretation, there is a need to study yield accumulation on both a fresh and dry weight basis. This study analysed the pattern of sucrose accumulation in the stalk in relation to crop biomass, and the concentration of sucrose in the stalk on a fresh and dry weight basis of two contrasting cultivars (Q117 and Q138) of sugarcane during the same season in tropical Australia, with irrigation and under plant and ratoon crop conditions. Over the 15 month season, 11 crop samplings were conducted. The key findings were that (1) greater than 95% of the aboveground sucrose accumulation is in the stalk; (2) a logistic relationship described the time trend in stalk sucrose accumulation, with maximum sucrose yield occurring 100 days before final harvest; (3) stalk biomass rather than stalk sucrose concentration was the major determinant of stalk sucrose accumulation; (4) maximum stalk sucrose concentration was stable across cultivars and crop classes at a value of 0.48 g g−1 stalk dry weight; (5) commercial yield expressed as the fresh millable stalk yield plateaued up to 230 days before final harvest and well before the attainment of maximum stalk biomass and sucrose yield due to increases in dry matter content during growth; (6) maximum stalk sucrose concentration on a fresh weight basis was obtained at a later crop age and was more variable across crops than maximum stalk sucrose concentration on a dry weight basis. The study highlighted the major influence that stalk dry matter content has on the relationship between sucrose yield and commercial yield, and that biological interpretation of crop response to climatic and management factors is difficult based on commonly available fresh weight measures of productivity. Optimising economic return from commercial sugarcane production requires further understanding on the factors controlling the dynamics of stalk dry matter content.

There is little detailed information on yield accumulation in sugarcane under high-input conditions, which can be used to quantify the key physiological parameters contributing to yield variation. Sugarcane is grown under plant and ratoon crop conditions. This study analysed canopy development, radiation interception and biomass accumulation of two contrasting cultivars of sugarcane under irrigation during the same season under plant and ratoon crop conditions. Over the 15 month season, 11 crop samplings were conducted. Biomass partitioning to stalk was also measured to determine to what extent differences in partitioning between cultivars under ratoon and plant crop conditions contribute to differential productivity. The key findings were: (1) The ratoon crop accumulated biomass more quickly than the plant crop during the first 100 days of growth due to higher stalk number, faster canopy development and greater radiation interception. For similar reasons, cultivar Q138 had higher early biomass production than cultivar Q117 in the plant crop. (2) Early differences in biomass accumulation due to crop class became negligible at about 220 days because maximum RUE of the plant crop (1.72 ± 0.01 g MJ −1 ) was 8% higher than in the first ratoon crop (1.59 ± 0.08 g MJ −1 ). The higher maximum RUE in the plant crop was consistent with a higher crop growth rate (35.1 ± 2.3 versus 31.0 ± 3.4 g m −2 d −1 ) during the linear phase of biomass accumulation. (3) Biomass accumulation, which ceased about 300 days after planting/ratooning and 140 days before final harvest, attained similar levels of 53–58 t ha −1 in all four crops. (4) The plateau in biomass was associated with loss of live millable stalks, and not a cessation in the growth rate of individual stalks. The crops continued to intercept radiation while on the biomass plateau, so that average RUEs at final harvest were much lower than the maximum values. (5) There was no effect of crop class or cultivar on the fraction of biomass in the leaf and millable stalk components. This study emphasizes that maximising early radiation interception and biomass accumulation will not necessarily lead to higher yield in an environment where biomass production reaches a plateau well before final harvest. Loss of live millable stalks late in the crop cycle results in poor utilisation of intercepted radiation.

Sugarcane is harvested commercially at ages varying from 9 to 36 months. Since high N supply can decrease the sucrose concentration in fresh millable stalks and consequently decrease the commercial value of the stalks, the opportunity exists to manipulate N supply (both from fertiliser and that mineralised from soil organic matter) to maximise economic return at different times of harvest. Accordingly, this study describes how N supply the time-course of sucrose accumulation in sugarcane and determines yield both on a dry weight basis (as commonly analysed by crop physiologists) and on a fresh weight basis (which is how cane is paid for commercially). Data on crop N uptake and its efficiency of utilisation are also presented. There was a trade-off between maximising sucrose yield and sucrose concentration in fresh millable stalks with different N supply and this varied with time of harvest. Sucrose concentration in fresh millable stalks, particularly during early growth, was maximised by low N supply. The lower sucrose concentration (on a fresh weight basis) with high N supply could be largely explained by a decrease in stalk dry matter content. Most of the variation in stalk sucrose yield could be explained by variation in stalk biomass irrespective of N supply. Whilst increasing N supply decreased the sucrose concentration in dry millable stalks, this effect was relatively small compared to the large positive effect of N supply on stalk biomass. It is concluded that N has a marked effect on stalk dry matter content, and hence a greater effect on the commercial measures (yield and sucrose concentration of fresh millable stalks) of sugarcane production than on the physiological measures (stalk biomass and sucrose concentration on a dry weight basis) of crop performance.

An InGaAsP-InP 2*2 laser amplifier gate switch matrix operating at 1.5 mu m with a fiber-to-fiber insertion loss of 3 dB is reported. The switch consists of passive waveguides for branching and recombining, monolithically integrated with laser amplifiers. The passive waveguides perform the signal routing, and the amplifiers provide gain/absorption in each path for on/off switching, achieving gain in the on state to compensate the losses. Dry-etched total internal reflection mirrors are employed as 90 degrees waveguide corner mirrors and also incorporated in the splitters in order to give a compact design. The on/off extinction ratio is >45 dB and the crosstalk is >

In grain legumes, nitrogen (N) accumulation is closely linked to biomass accumulation and seed growth. Quantitative information on N accumulation, its partitioning to leaf N, and the partitioning of biomass and N to grain yield under varying environmental conditions is required for the development of crop growth models to allow the assessment of production risk. Accordingly, these processes were quantified in soybean (Glycine max L.), mungbean (Vigna radiata) and cowpea (Vigna unguiculata) under different radiation and temperature regimes, and varying levels of water deficit in tropical and subtropical environments. Across environments, net N accumulation was linearly related to net above-ground biomass throughout growth until just prior to maturity, with a higher rate in soybean than in mungbean and cowpea. For all three species and in all environments during vegetative growth, 70% of N and 50% of biomass accumulation was partitioned to the leaf. Grain N concentration for each species was stable throughout pod-filling and across environments. During pod-filling, soybean accumulated more above-ground N than mungbean and cowpea. Pod N accumulation commonly exceeded net above-ground N accumulation with the extent of reduction in vegetative N during pod-filling varying widely across environments. Vegetative N decline during pod-filling was associated with reduction in leaf N but not always reduction in stem N. Loss of leaf N during pod-filling was due to leaf loss rather than reduction in specific leaf N. Grain yield was proportional to net above-ground biomass at maturity, and grain N accumulation was proportional to net above-grund N accumulation over the entire yield range in this study, particularly for soybean and mungbean. Consequently, there was no differential effect of environmental factors on yield physiology that could not be explained by their effect on biomass and N accumulation.

CD56dim NK cells, which comprise approximately 90% of human peripheral blood NK cells, respond to IL-2 with cytokine production, up-regulation of functionally relevant surface molecules, and augmented cytolytic activity. Nevertheless, CD56dim NK cells proliferate poorly in response to IL-2 alone. We found that other NK cell mitogens, including IL-4, IL-7, and IL-12, also induced little proliferation of CD56dim NK cells. Indeed, IL-2 stimulated at least 10-fold more NK cell proliferation than did IL-4, IL-7, or IL-12. In contrast, leukocyte-conditioned medium (LCM) induced two- to threefold greater proliferation of CD56dim NK cells than did optimal concentrations of IL-2. Although the calcium ionophore ionomycin did not stimulate proliferation by itself, it markedly augmented LCM-induced proliferation of CD56dim NK cells. Proliferation in response to either LCM alone or LCM together with ionomycin was almost completely abrogated by anti-IL-2R antibodies. Thus, IL-2 appears to be necessary but not sufficient for optimal proliferation of CD56dim NK cells. LCM-induced proliferation of ionomycin-activated CD56dim NK cells was inhibited 24% by anti-IL-1 heteroantisera and 57% by anti-TNF antisera; a combination of both antisera inhibited proliferation by 73%. Furthermore, although rIL-1 and TNF did not induce proliferation by themselves, both cytokines could augment IL-2-induced proliferation of resting or ionomycin-activated NK cells. Hence IL-1 and TNF do not appear to be primary NK cell mitogens, but rather accessory factors that can enhance IL-2-dependent NK cell proliferation. Stimulation through CD2 or CD16 Ag did not enhance LCM-induced NK cell proliferation. However, stimulation with NK-sensitive K562 cells strongly augmented CD56dim NK cell proliferation to LCM or to IL-2, IL-1, and TNF in combination. NK-resistant Daudi cells did not promote the proliferation of highly purified NK cells. Thus, NK cell proliferation may be enhanced by triggering through putative receptors for natural killing, and ionomycin may mimic such triggering. Although IL-2 by itself can induce NK cell proliferation, most NK cells resemble T and B lymphocytes in that they require multiple signals for optimal proliferation.

Radiation-use efficiency (RUE), defined as the amount of biomass accumulated per unit radiation intercepted, is a key measure of the photosynthetic performance of crops growing in different environments. The RUE of soybean (Glycine max L.), mungbean (Vigna radiata) and cowpea (Vigna unguiculata) growing under well-watered field conditions in tropical and subtropical environments was determined from frequent biomass samplings and continuous logging of intercepted radiation throughout growth. The slope of the relationship between net biomass accumulation and intercepted radiation was linear throughout most of growth, almost until the end of pod-filling in all species and all environments. The decrease in RUE just prior to maturity was associated with losses of biomass due to leaf shedding, and also with a decline in specific leaf nitrogen. The RUE during the linear phase was slightly higher in cowpea than in mungbean and soybean. For each species, the RUE was similar in different environments despite large differences in air temperature, water vapour saturation deficit and incident radiation. It was concluded that RUE under well-watered conditions is constant througout most of growth and unaffected by the aerial environment. Baseline values of RUE were 0.88 g MJ−1 for soybean, 0.94 g MJ−1 for mungbean, and 1.05 g MJ−1 for cowpea.

The CD27 Ag is expressed by the majority of resting T lymphocytes and appears to play a crucial role in T cell activation. We found that some resting peripheral blood NK cells also express CD27. Furthermore, CD27 expression was up-regulated on NK cells stimulated by IL-2. The cytolytic activity of IL-2-activated, but not resting, NK cells was inhibited by an anti-CD27 mAb (anti-1A4). However, anti-1A4 did not affect conjugate formation between IL-2-activated NK cells and tumor cell targets. In contrast, anti-1A4 inhibited CD2-mediated calcium mobilization and the serine esterase activity of NK cell granules. These inhibitory effects could be mediated in part by increase in intracellular cAMP levels induced by anti-1A4. Our results suggest that the CD27 Ag plays an important role in the regulation of activated NK cells.

The aim of this study was to investigate whether the pentobarbitone anesthetized cat is a suitable preparation in which to characterize renal tubular dopamine receptors. Intravenous infusion of dopamine (10-100 micrograms/kg/min) resulted in a dose-related increase in mean blood pressure (MBP), urine output, sodium excretion (UNaV), and fractional sodium excretion (FENa). This diuretic effect occurred despite little change in glomerular filtration rate, suggesting that it is a consequence of decreased tubular reabsorption. Dopamine (10-100 micrograms/kg/min, i.v.) also induced marked dose-related falls in renal vascular conductance; however, renal blood flow was not significantly reduced. The increases in MBP, urine output, UNaV, and FENa induced by dopamine (10-100 micrograms/kg/min, i.v.), were unaffected by pretreatment of cats with either the selective dopamine DA1 or DA2 receptor antagonists, SCH 23390 (30 micrograms/kg, i.v.), or domperidone (100 micrograms/kg, i.v.) respectively. In contrast, pretreatment of cats with the nonselective alpha-adrenoceptor antagonist, phentolamine (1 mg/kg, i.v.) prevented dopamine-induced increases in urine output and MBP. Infusion of the selective dopamine DA1 receptor agonist fenoldopam (0.01-10 micrograms/kg/min) into the left renal artery failed to increase left renal vascular conductance, or left kidney urine output, UNaV, or FENa. In conclusion, this study provides no evidence for the involvement of renal tubular dopamine receptors in dopamine-induced diuresis in anesthetized cats. Rather, the diuretic effect appears to be linked to stimulation of alpha-adrenoceptors.

This paper describes the synthesis and pharmacology of a novel series of benzofurans which are antagonists of angiotensin II. One of these, the bromobenzofuran 11b, is a potent (apparent pKB=9.8) and specific antagonist of angiotensin II which, after oral administration (10mg/Kg), causes marked and long-lasting ( > 24h) falls in blood pressure in renal hypertensive rats.

Cell adhesion molecules (CAM) participate in interactions between lymphocytes, accessory cells, and target cells that are critical in the generation of effective immune responses. To characterize the involvement of CAM in NK and lymphokine activated killer (LAK) activities, we examined the expression of several CAM by freshly isolated human NK cells and by NK cells activated in vitro with IL-2, and compared this to CAM expression by T lymphocytes under similar conditions. Freshly isolated human NK cells were uniformly LFA-3 (CD58)+ and expressed two to three-fold higher surface levels of LFA-1 (CD11a/CD18) than resting T lymphocytes. More NK cells than T cells also expressed phenotypically detectable levels of intercellular adhesion molecule-1 (CD54). After in vitro incubation with IL-2, human NK cells demonstrated four- to sixfold increases in surface levels of CD11a/CD18, CD2, CD54, CD58, and the NK cell-associated Ag NKH-1 (CD56). Furthermore, essentially all NK cells became CD54+ within 3 days of exposure to IL-2. T cells did not demonstrate comparable up-regulation of CAM after incubation with IL-2. Increases in NK cell CAM expression were associated with enhanced formation of E:T cell conjugates, enhanced killing of NK-sensitive targets, and the induction of cytotoxicity for previously NK-resistant targets (LAK activity). The LAK activity induced by exogenous IL-2 could be partially inhibited by anti-CD2, anti-CD11a, or anti-CD54 antibodies and almost completely abrogated by anti-CD2 and anti-CD11a in combination. These studies suggest that CAM play a central role in the regulation of NK cytolysis, and that changes in CAM expression may alter the target cell specificity of activated NK effectors.