Production and carbon allocation in a clonal Eucalyptus plantation with water and nutrient manipulations

We examined resource limitations on growth and carbon allocation in a fast-growing, clonal plantation of Eucalyptus grandis x urophylla in Brazil by characterizing responses to annual rainfall, and response to irrigation and fertililization for 2 years. Productivity measures included gross primary production (GPP), total belowground carbon allocation (TBCA), bole growth, and net ecosystem production (NEP). Replicate plots within a single plantation were established at the midpoint of the rotation (end of year 3), with treatments of no additional fertilization or irrigation, heavy fertilization (to remove any nutrient limitation), irrigation (to remove any water limitation), and irrigation plus fertilization. Rainfall was unusually high in the first year (1769mm) of the experiment, and control plots had high rates of GPP (6.64 kg C m(-2) year(-1)), TBCA (2.14 kg C m(-2) year(-1)), and bole growth (1.81 kg C m(-2) year). Irrigation increased each of these rates by 15-17%. The second year of the experiment had average rainfall (1210 mm), and lower rainfall decreased production in control plots by 46% (GPP), 52% (TBCA), and 40% (bole growth). Fertilization treatments had neglible effects. The response to irrigation was much greater in the drier year, with irrigated plots exceeding the production in control plots by 83% (GPP), 239% (TBCA), and 24% (bole growth). Even though the rate of irrigation ensured no water limitation to tree growth, the high rainfall year showed higher production in irrigated plots for both GPP (38% greater than in drier year) and bole growth (23% greater). Varying humidity and supplies of water led to a range in NEP of 0.8-2.7 kg C m(-2) year. This difference between control and irrigated treatments, combined with differences between drier and wetter years, indicated a strong response of these Eucalyptus trees to both water supply and atmospheric humidity during the dry season. The efficiency of converting light energy into fixed carbon ranged from a low of 0.027 mol C to a high of 0.060 mol C per mol of absorbed photosynthetically active radiation (APAR), and the efficiency of bolewood production ranged from 0.78 to 1.98 g wood per MJ of APAR. Irrigation increased the efficiency of wood production per unit of water used from 2.55 kg wood m(-3) in the rainfed plot to 3.51 kg m(-3) in irrigated plots. Detailed information on the response of C budgets to environmental conditions and resource supplies will be necessary for accurate predictions of plantation yields across years and landscapes. (V) 2007 Elsevier B.V. All rights reserved.

Apparent digestibility coefficients of selected feed ingredients for dourado Salminus brasiliensis

The excellence of its flesh and fast growth makes the dourado, Salminus brasiliensis, a carnivorous fish native to the Prata basin, a potential candidate for intensive fish farming. This study evaluated the apparent digestibility coefficients (ADC) of energy and nutrients of animal and plant protein sources for the carnivorous Characin dourado S. brasiliensis. Fish (19.5 +/- 5.0 g) were stocked in plastic cages (80-L) and fed pelleted test diets containing 30% of the test ingredient [fish meal (FM), poultry by-product meal (PBM), soybean meal (SBM), and corn gluten meal (CGM) plus 70% of a reference diet (481.4 g kg(-1) of crude protein and 18.63 kJ of gross energy per gram]. After the last daily meal, cages were transferred to cylindrical, conical-bottomed aquarium (200-L) where faeces were collected by sedimentation in a refrigerated container. Except for ADC of protein and energy, all other ADC of nutrients showed significant differences (P < 0.01). ADC values were: 94.3%, 91.3%, 93.1%, and 93.5% for crude protein; 91.0%, 90.3%, 87.8%, and 88.8% for gross energy; 92.1%, 84.5%, 80.6%, and 79.3% for ash; 83.9%, 80.3%, 84.3%, and 84.6% for dry matter; 97.4%, 96.7%, 93.3%, and 91.5% for lipid for FM, PBM, SBM, and CGM, respectively. The average amino acid ADC was: 93.6%, 90.0%, 92.1%, and 92.5% of FM, PBM, SBM, and CGM, respectively. All test ingredients were efficiently used and can partially replace FM in diets for carnivorous dourado.

Preweaning performance and body composition of calves from straightbred Nellore and Bos taurus x Nellore crosses

The objectives were to evaluate preweaning performance, body composition, and efficiency of calves representing straightbred Nellore (NL), F(1), and 3-breed-cross systems. Energy requirements, milk production, and efficiency of 39 cow-calf pairs were recorded from straightbred NL calves from NL cows (10), crossbred (Angus-sired) calves from NL cows (ANL: 9), and crossbred calves (CC; Canchim-sired: 5/8 Charolais, 3/8 Zebu) from ANL (10) and Simmental x NL (10) cows. Cows and their respective calves were individually fed from birth to weaning (17 to 190 d postpartum). At 38 d of age, corn silage (7.8% CP, 2.19 Mcal of ME/kg of DM) was available to calves ad libitum. Milk production at 42, 98, 126, and 180 d postpartum was recorded by weighing calves before and after suckling. The ratio between GE and ME of milk was considered 1:0.93. Calves were slaughtered at weaning and the 9th-, 10th-, and 11th-rib section was removed for body composition estimation. The ANL calves were lighter (P < 0.01) at birth than the CC calves; the NL calves were intermediate. At weaning, the CC calves were heavier (P = 0.04) than the NL and ANL calves (230 +/- 5.5 vs. 172 +/- 8.1 and 209 +/- 8.6 kg, respectively). The ANL calves had greater (371 +/- 27 Mcal; P = 0.01) silage intake than the NL (270 +/- 25 Mcal) and CC (279 +/- 17 Mcal) calves. Milk energy intake was greater for the CC calves (970 +/- 38 Mcal of ME; P = 0.005) than the NL (670 +/- 57 Mcal of ME) and ANL (743 +/- 61 Mcal of ME) calves. The ANL calves compensated for the reduced milk production of the NL cows, which supplied less of their energy requirement for growth by increased silage intake. Calves from crossbred cows received a greater proportion of their total energy intake from milk. Crossbred calves had greater (P < 0.03) retained energy (retained energy = weaning body energy - birth body energy) than the NL calves (388 +/- 23 for ANL, and 438 +/- 15 for CC vs. 312 +/- 22 Mcal for NL calves). Percentages of water (P = 0.74) and chemical fat (P = 0.51) were similar among groups (63.7 +/- 0.6 and 14.3 +/- 0.7% for ANL calves, 63.1 +/- 0.4 and 14.7 +/- 0.5% for CC calves, and 63.3 +/- 0.6 and 13.7 +/- 0.7% of empty BW for water and chemical fat, respectively, for NL calves). Energetic efficiency (kcal of retained energy/Mcal of ME intake) was similar (P = 0.52) among groups (358 +/- 22 for ANL calves, 355 +/- 14 for CC calves, and 327 +/- 22 for NL calves). The greater BW gains and the differences in empty body composition at weaning were not enough to compensate for the greater ME intake of crossbreds. In this study, the crossbreeding systems evaluated increased preweaning calf performance but did not affect gross or energetic calf efficiency.

Thermal effects in the evolution of initially layered mantle material

A simplified model for anisotropic mantle convection based on a novel class of rheologies, originally developed for folding instabilities in multilayered rock (MUHLHAUS et al., 2002), is extended ¨ through the introduction of a thermal anisotropy dependent on the local layering. To examine the effect of the thermal anisotropy on the evolution of mantle material, a parallel implementation of this model was undertaken using the Escript modelling toolkit and the Finley finite-element computational kernel (DAVIES et al., 2004). For the cases studied, there appears too little if any effect. For comparative purposes, the effects of anisotropic shear viscosity and the introduced thermal anisotropy are also presented. These results contribute to the characterization of viscous anisotropic mantle convection subject to variation in thermal conductivities and shear viscosities.

Analysis and application of an equilibrium model for in vitro bioassay systems with three components: Receptor, hormone and hormone-binding-protein

A simple theoretical framework is presented for bioassay studies using three component in vitro systems. An equilibrium model is used to derive equations useful for predicting changes in biological response after addition of hormone-binding-protein or as a consequence of increased hormone affinity. Sets of possible solutions for receptor occupancy and binding protein occupancy are found for typical values of receptor and binding protein affinity constants. Unique equilibrium solutions are dictated by the initial condition of total hormone concentration. According to the occupancy theory of drug action, increasing the affinity of a hormone for its receptor will result in a proportional increase in biological potency. However, the three component model predicts that the magnitude of increase in biological potency will be a small fraction of the proportional increase in affinity. With typical initial conditions a two-fold increase in hormone affinity for its receptor is predicted to result in only a 33% increase in biological response. Under the same conditions an Ii-fold increase in hormone affinity for receptor would be needed to produce a two-fold increase in biological potency. Some currently used bioassay systems may be unrecognized three component systems and gross errors in biopotency estimates will result if the effect of binding protein is not calculated. An algorithm derived from the three component model is used to predict changes in biological response after addition of binding protein to in vitro systems. The algorithm is tested by application to a published data set from an experimental study in an in vitro system (Lim et al., 1990, Endocrinology 127, 1287-1291). Predicted changes show good agreement (within 8%) with experimental observations. (C) 1998 Academic Press Limited.

Morphology of the thyroid in coastal and noncoastal populations of the koala (Phascolarctos cinereus) in Queensland

The gross morphology, histology, and ultrastructure of the thyroid gland of the koala, Phascolarctos cinereus, is described. Generally, the glands were found to contain large-diameter follicles in association with an epithelium of low height. Morphometric analysis demonstrated a high relative thyroid weight (0.3 +/- 0.2 g/kg) for koalas compared with the 0.07-0.24 g/kg typical of eutherian mammals and 0.03-0.1 g/kg found in other marsupials. The relative thyroid weight of glands (0.33 +/- 0.21 g/kg) from the coastal population (less than 28 km from the coastline) was found to be significantly higher (ANOVA: P = 0.007, significant at the 1% level) than that for glands (0.21 +/- 0.11 g/kg) of noncoastal koalas (greater than 28 km from the coastline). Follicle size was positively correlated (at the 0.1% level) with relative thyroid weight in the overall koala sample. The presence of C cells, occurring singly in the epithelial layer, was demonstrated in electron micrographs. Structural features such as low epithelial height, large follicle length and width, and large intercellular spaces in association with low concentrations of free TS (3.3 +/- 2.1 pM) and free T-3 (1.4 +/- 0.9 pM) as reported previously (Lawson et al., 1996) are consistent with an unusually low level of glandular activity in the koala thyroid even though iodine concentrations in the thyroid gland [4.7 +/- 1.6 mg/g (dry weight)] as well as leaf [0.8 +/- 0.3 mu g (dry weight)] and soil samples [3.8 mu g/g (dry weight)] from the koalas' habitat appear unremarkable. (C) 1998 Academic Press.

Moneyless business exchange - Practitioners' attitudes to business-to-business barter in Australia

In recent years, domestic business-to-business barter has become institutionalized as an alternative marketing exchange system in Australia, and elsewhere. This article reports the findings of a survey of 164 members of Australia's largest trade exchange, Bartercard There are few, if any, published empirical studies on this topic. This study is exploratory. Most firms surveyed are small firms in the services sectors. Although Bartercard has an extensive membership, trading within the system is limited with most members trading less than once per week and with barter transactions contributing less than 5% of their annual gross sales. The main benefits of membership include new customers and increased sales and networking opportunities. The main limitations include the limited functionality of the trade dollar limited trading opportunities, and practical trading difficulties. In selling, there appears to be no differential between the cash and trade prices, whereas trade dollars are discounted in purchasing. Participants acknowledge that business-to-business barter will remain and grow regardless of cyclical macroeconomic changes. (C) 1998 Elsevier Science Inc.

Trunculins G-I: New norsesterterpene cyclic peroxides from a southern Australian marine sponge, Latrunculia sp.

A Latrunculia sp, collected off Port Phillip Bay, Victoria, returned three new norsesterterpene cyclic peroxides. Trunculins G (9), H (10) and I (11) were isolated as their methyl esters (12), (13) and (14) respectively. Gross structures for these new trunculins were assigned on the basis of spectroscopic analysis, while the absolute stereochemistry about the cyclic peroxide terminus was established by application of the Horeau and Mosher procedures.

Influence of field-based nutrient enrichment on the photobiology of the giant clam Tridacna maxima

Nutrients were added to 12 microatolls in One Tree Island lagoon every low tide for 13 mo to an initial concentration of 10 mu M (ammonium, N) and 2 mu M (phosphate, P). These concentrations remained above background for 2 to 3 h after addition. The addition of ammonium (N and NI-P but not P alone) significantly increased P, (gross photosynthesis) P,, (net photosynthesis) and R (respiration) per unit wet-tissue weight and cc (photosynthetic efficiency) in Tridacna maxima after 3 mo nutrient enrichment. These responses to small and transient changes in ammonium concentrations suggest that symbiotic clams are not nutrient-replete, and that even subtle changes in nutrients can have a measurable effect on photosynthesis. The same clams did not show significant differences in photosynthetic parameters 6 mo after the beginning of nutrient enrichment, suggesting that their previous responses had either been seasonal or that symbiotic clams such as T. maxima are able to adjust their photophysiology following external changes in nutrient concentrations.

Implication of the visual system in the regulation of activity cycles in the absence of solar light: 2-[I-125]iodomelatonin binding sites and melatonin receptor gene expression in the brains of demersal deep-sea gadiform fish

Relative eye size, gross brain morphology and central localization of 2-[I-125]iodomelatonin binding sites and melatonin receptor gene expression were compared in six gadiform fish living at different depths in the north-east Atlantic Ocean: Phycis blennoides (capture depth range 265-1260 m), Nezumia aequalis (445-1512 m), Coryphaenoides rupestris (706-1932 m), Trachyrincus murrayi (1010-1884 m), Coryphaenoides guentheri (1030 m) and Coryphaenoides (Nematonurus) armatus (2172-4787 m). Amongst these, the eye size range was 0.15-0.35 of head length with a value of 0.19 for C.(N.) armatus, the deepest species. Brain morphology reflected behavioural differences with well-developed olfactory regions in P.blennoides, T.murrayi and C. (N.) armatus and evidence of olfactory deficit in N. aequalis, C. rupestris and C. guentheri. All species had a clearly defined optic tectum with 2-[I-125] iodomelatonin binding and melatonin receptor gene expression localized to specific brain regions in a similar pattern to that found in shallow-water fish. Melatonin receptors were found throughout the visual structures of the brains of all species. Despite living beyond the depth of penetration of solar light these fish have retained central features associated with the coupling of cycles of growth, behaviour and reproduction to the diel light-dark cycle. How this functions in the deep sea remains enigmatic.

Desiccation tolerance of three moss species from continental Antarctica

Tolerance of desiccation was examined in three species of moss, Grimmia antarctici Card., Ceratodon purpureus (Hedw.) Brid. and Bryum pseudotriquetrum (Hedw.) Gaertn., Meyer et Scherb. collected from two sites of contrasting water availability in the Windmill Islands, continental Antarctica. Physiological tolerance to desiccation was measured using chlorophyll fluorescence in plugs of moss during natural drying in the laboratory. Differences in relative water content, rate of drying and the response of photosynthesis to desiccation were observed among the three species and between sites. Of the three species studied, G. antarctici showed the lowest capacity to sustain photosynthetic processes during desiccation, B. pseudotriquetrum had an intermediate response and showed the greatest plasticity and C. purpureus showed the greatest capacity to sustain photosynthesis during desiccation. These results fit well with the known distribution of the three species with G. antarctici being limited to relatively wet sites, C. purpureus being common in the driest sites and B. pseudotriquetrum showing a wide distribution between these two extremes. Levels of soluble carbohydrates were also measured in these samples following desiccation and these indicate the presence of stachyose, an oligosaccharide known to be important in desiccation tolerance in seeds, in B. pseudotriquetrum. Both gross morphology and carbohydrate content are likely to contribute to differences in desiccation tolerance of the moss species. These results indicate that if the Casey region continues to dry out, as a result of local geological uplifting or global climate change, we would expect to see not only reductions in the moss community but also changes in community composition. G. antarctici is likely to become more limited in distribution as C. purpureus and B. pseudotriquetrum expand into drying areas.

Community structure of Quaternary coral reefs compared with Recent life and death assemblages

This paper assesses the reliability with which fossil reefs record the diversity and community structure of adjacent Recent reefs. The diversity and taxonomic composition of Holocene raised fossil reefs was compared with those of modern reef coral life and death assemblages in adjacent moderate and low-energy shallow reef habitats Of Madang Lagoon, Papua New Guinea. Species richness per sample area and Shannon-Wiener diversity (H') were highest in the fossil reefs, intermediate in the life assemblages, and lowest in the death assemblages. The taxonomic composition of the fossil reefs was most similar to the combination of the life and death assemblages from the modern reefs adjacent to the two fossil reefs. Depth zonation was recorded accurately in the fossil reefs. The Madang fossil reefs represent time-averaged composites of the combined life and death assemblages as they existed at the time the reef was uplifted. Because fossil reefs include overlapping cohorts from the life and death assemblages, lagoonal facies of fossil reefs are dominated by the dominant sediment-producing taxa, which are not necessarily the most abundant in the life assemblage. Rare or slow-growing taxa accumulate more slowly than the encasing sediments and are underrepresented in fossil reef lagoons. Time-averaging dilutes the contribution of rare taxa, rather than concentrating their contribution. Consequently, fidelity indices developed for mollusks in sediments yield low values in coral reef death and fossil assemblages. Branching corals dominate lagoonal facies of fossil reefs because they are abundant, they grow and produce sediment rapidly, and most of the sediment they produce is not exported. Fossil reefs distinguished kilometer-scale variations in community structure more clearly than did the modern life assemblages. This difference implies that fossil,reefs may provide a better long-term record of community structure than modern reefs. This difference also suggests that modern kilometer-scale variation in coral reef community structure may have been reduced by anthropogenic degradation, even in the relatively unimpacted reefs of Madang Lagoon. Holocene and Pleistocene fossil reefs provide a time-integrated historical record of community composition and may be used as long-term benchmarks for comparison with modern, degraded, nearshore reefs. Comparisons between fossil reefs and degraded modern reefs display gross changes in community structure more effectively than they demonstrate local extinction of rare taxa.

Kinetics of photoacclimation in corals

Traditional models describing the relationship between photosynthesis (P) and irradiance (I) do not account for photoacclimation to short-term variation in irradiance. Here we develop and test a model that predicts the rate of photosynthesis under fluctuating irradiances at the scale of days to weeks. Using oxygen respirometry, we measured the rates of change in the P-I model parameters P-max (maximum rate of gross photosynthesis) and I-k (sub-saturation irradiance) of the photo-symbiotic coral Turbinaria mesenterina (Lamarck) following large and small increases and decreases in growth irradiance. We analyse the behaviour of the dynamic P-I model in turbid-water conditions using a dataset of 3-month continuous irradiance as the input variable. In response to upward or downward changes in experimental growth irradiance, I-k values decreased or increased exponentially, reaching new and stable levels within 5-10 days. I-k responded 4 times stronger than P-max to changes in growth irradiance. The kinetics of I-k did not show hysteresis, and changed in similar ways when irradiance was increased or decreased in small or large amounts. This suggests that mechanisms associated with photo-protection during increases in irradiance, and the maximisation of photosynthetic efficiency during decreases in irradiance, are equally potent. On the scale of months, the dynamic P-I model did not predict higher rates of photosynthesis than the static P-I model, but buffered the variation in photosynthesis during periods of reduced irradiance. Fourier analysis indicated that the kinetics of I-k closely matches the main periodicities in daily irradiance (1-2 weeks). The recorded kinetics of photoacclimation in the Turbinaria-zooxanthella symbiosis is comparable to that of free-living phytoplankton and faster than that of higher plants.

Stability property of matchings is a natural solution concept in coalitional market games

Stability of matchings was proved to be a new cooperative equilibrium concept in Sotomayor (Dynamics and equilibrium: essays in honor to D. Gale, 1992). That paper introduces the innovation of treating as multi-dimensional the payoff of a player with a quota greater than one. This is done for the many-to-many matching model with additively separable utilities, for which the stability concept is defined. It is then proved, via linear programming, that the set of stable outcomes is nonempty and it may be strictly bigger than the set of dual solutions and strictly smaller than the core. The present paper defines a general concept of stability and shows that this concept is a natural solution concept, stronger than the core concept, for a much more general coalitional game than a matching game. Instead of mutual agreements inside partnerships, the players are allowed to make collective agreements inside coalitions of any size and to distribute his labor among them. A collective agreement determines the level of labor at which the coalition operates and the division, among its members, of the income generated by the coalition. An allocation specifies a set of collective agreements for each player.