Carbon uptake by secondary forests in Brazilian Amazonia

Estimating the contribution of deforestation to greenhouse gas emissions requires calculations of the uptake of carbon by the vegetation that replaces the forest, as well as the emissions from burning and decay of forest biomass and from altered emissions and uptakes by the soil. The role of regeneration in offsetting emissions from deforestation in the Brazilian Legal Amazon has sometimes been exaggerated. Unlike many other tropical areas, cattle pasture (rather than shifting cultivation) usually replaces forest in Brazilian Amazonia. Degraded cattle pastures regenerate secondary forests more slowly than do fallows in shifting cultivation systems, leading to lower uptake of carbon. The calculations presented here indicate that in 1990 the 410 × 10³ km² deforested landscape was taking up 29 × 10⁶ t of carbon (C) annually (0.7 t C ha⁻¹ year⁻¹). This does not include the emissions from clearing of secondary forests, which in 1990 released an estimated 27 × 10⁶ t C, almost completely offsetting the uptake from the landscape. Were the present land-use change processes to continue, carbon uptake would rise to 365 × 10⁶ t annually (0.9 t C ha⁻¹ year⁻¹) in 2090 in the 3.9 × 10⁶ km⁶ area that would have been deforested by that year. The 1990 rate of emissions from deforestation in the region greatly exceeded the uptake from regrowth of replacement vegetation.     

Large mulches and manual release enhance growth of ponderosa pine seedlings

Woody and herbaceous vegetation that captures scarce soil moisture often kills or stunts the growth of conifer seedlings in young plantations in the Sierra Nevada of California. Two methods for excluding this vegetation are to apply large (3-m×3-m), long-lasting (at least 5 years) mulches around the seedlings soon after planting, or to repeatedly grub seedlings of competing vegetation in study plots. Both techniques were tested and proved to be effective, significantly increasing ponderosa pine diameter and height relative to the control and to seedlings surrounded by small paper mulches. The effective treatments were large enough to enable conifer seedlings to capture site resources unimpeded by competing plants. Eight species of shrubs, seventeen forbs, four grasses, and one fern grew naturally on the study site.Results suggest that the forester now has two biologically effective means for controlling unwanted vegetation and for attaining rapid early pine growth in environments similar to the study area. Although more expensive, the large heavy polyester mulches ($9.90 per seedling over 5 years) give the forester an alternative to manual release ($2.05 per seedling over 5 years).     

Safety evaluation of the canine osteosarcoma vaccine,live Listeria vector

Canine osteosarcoma (OSA) is an aggressive bone tumour in dogs. Standard‐of‐care treatment typically results in relatively short survival times; thus, alternative treatments are needed to confer a survival advantage. It has been shown that OSA is an immunogenic tumour, suggesting that immune modulation may result in superior outcomes. A cryopreserved, Listeria‐based OSA vaccine was recently developed and an initial study in dogs reported prolonged survival for patients receiving the vaccine in conjunction with standard‐of‐care. The goal of the current observational study was to report on the safety of the lyophilized formulation of this vaccine (the canine OSA vaccine, live Listeria vector [COV‐LLV]) in a group of dogs previously diagnosed with OSA. Forty‐nine (49) dogs received the COV‐LLV and were included for analysis. Adverse events (AEs) noted during and after vaccinations were recorded. The AEs observed were typically mild and self‐limiting, with nausea, lethargy and fever being most common. Four dogs (8%) cultured positive for Listeria (three infections including an amputation site abscess, septic stifle joint and bacterial cystitis; and one dog whose lungs cultured Listeria‐positive on necropsy within 24 hours of COV‐LLV administration). These cases join the previously reported Listeria‐positive thoracic abscess that developed in a canine following use of COV‐LLV. Although uncommon, it is important to realize this clinically significant AE is possible in patients treated with live therapeutic Listeria vaccines. As Listeria is zoonotic, caution is required not only for the patient receiving the vaccine, but also for the health care workers and family caring for the patient.     

Errors in predicting furrow irrigation performance using single measures of infiltration

Commercial performance evaluations of surface irrigation are commonly conducted using infiltration functions obtained at a single inflow rate. However, evaluations of alternative irrigation management (e.g. flow rate, cut-off strategy) and design (e.g. field length) options using simulation models often rely on this single measured infiltration function, raising concerns over the accuracy of the predicted performance improvements. Measured field data obtained from 12 combinations of inflow rate and slope over two irrigations were used to investigate the accuracy of simulated surface irrigation performance due to changes in the infiltration. Substantial errors in performance prediction were identified due to (a) infiltration differences at various inflow rates and slopes and (b) the method of specifying the irrigation cut-off. Where the irrigation cut-off at various inflow rates was specified as a fixed time identified from simulations using the infiltration measured at a single inflow rate, then the predicted application efficiency was generally well correlated with the application efficiency measured under field conditions at the various inflow rates. However, the predictions of distribution uniformity (DU) were poor. Conversely, specifying the irrigation cut-off as a function of water advance distance resulted in adequate predictions of DU but poor predictions of application efficiency. Adjusting the infiltration function for the change in wetted perimeter at different inflow rates improved the accuracy of the performance predictions and substantially reduced the error in performance prediction associated with the cut-off recommendation strategy.     

Deposition of fine sediments in irrigation canals

Sediment control structures constructed at the heads of run-of-river irrigation schemes have little effect on the very fine sands and silts that settle in the smaller distribution canals. One means of minimising the effects of fine sediment deposition in small canals is to design canals so that deposition occurs at selected locations, rather than throughout the canal network. Standard sediment transport predictors cannot be used to predict the effects of changing canal slopes and cross sections when sediment sizes are very small, and thus cannot be used to determine dimensions and slopes of small canal settling basins.The paper presents a simple method for estimating the transport and deposition rates of fine sediment suspensions, for sediments in the cohesive size range. The method, which has been tested against a large data set, enables the effects of changing canal cross sections and slopes on fine sediment transport to be quantified.     

Blue Revolution or Red Herring? Fish Farming and Development Discourse in the Philippines

This paper argues that the discourses of development underpinning aquaculture as a development strategy are flawed because they neglect the impacts of fish farming on the local resource base and those social groups dependent upon it. The Philippine government has promoted aquaculture for over two decades, viewing it as a key component of national economic recovery. But field work in the Batan municipality of the Philippines reveals that the ‘common sense’ behind aquaculture is severely undermined when its effects on the physical environment and people in the vicinity of fishponds are examined.     

Condensed tannins in Trifolium species and their significance for taxonomy and plant breeding

Summary Populations of 59 Trifolium taxa were screened for condensed tannin content using the vanillin-HC1 test. Eight species (T. arvense, T. aureum, T. badium, T. campestre, T. dubium, T. micranthum, T. patens and T. spadiceum) were shown to contain tannins. These species are all found in Section Chronosemium or Section Trifolium Subsection Arvensia of the genus, and thus presence of tannins appears to have a taxonomic significance. Screening populations within species showed differences in tannin content, but no plants in these species were free of tannins.     

Analysis of the genotoxicity of municipal sewage sludge extracts with sister chromatid exchange in cultured human lymphocytes

The genotoxicity of extracts of anaerobically digested sewage sludge to human cells was assessed by measuring the induction of sister chromatid exchanges in human peripheral lymphocytes with and without mammalian hepatic microsomal activation. A 2 hr exposure time with a total culture time of 76 hr was necessary to circumvent problems with cell cycle delays induced by the agents present in the extracts. With this modified procedure, the three extracts tested demonstrated a statistically significant increase in the number of sister chromatid exchanges/chromosome observed suggesting the presence of a genotoxic component in the sewage sludge.     

Casein proteins as molecular chaperones

Under conditions of stress, such as elevated temperature, molecular chaperones stabilize proteins from unfolding, aggregating, and precipitating. We have investigated the chaperone activity of the major milk proteins alpha(S)-, beta-, and kappa-casein with reduced insulin and the milk whey proteins, alpha-lactalbumin and beta-lactoglobulin, and compared it with that of the mammalian small heat shock protein (sHsp), alpha-crystallin, and clusterin. alpha(S)-Casein exhibited different chaperone behavior under reduction and heat stresses, i.e., chaperone activity increased with increasing temperature (as observed with alpha-crystallin), but under reduction stress, its chaperone activity increased at lower temperatures. beta- and kappa-casein had comparable chaperone ability with each other but were less effective than alpha(S)-casein. Under molecular crowding conditions, precipitation of stressed protein was accelerated, and alpha(S)-casein was a poorer chaperone. Furthermore, at slightly alkaline pH values, alpha(S)-casein was a less effective chaperone than at neutral pH. Detailed fluorescence, size exclusion chromatography, and real-time NMR studies studies indicated that the casein proteins underwent conformational changes and stabilized the partially unfolded whey proteins prior to formation of high molecular weight soluble complexes. These results are consistent with casein proteins acting as molecular chaperones in a manner similar to sHsps and clusterin.