Nutrient deficiencies in lesser yam (Dioscorea esculenta) characterized using constant–water table sand culture

Nutritional deficiencies in Dioscorea esculenta (Lour.) Burk were studied using a novel culture system, applying a constant water table in acid‐washed sand, and a demand‐driven nutrient supply schedule. This system provided a stable growth environment and was highly efficient with respect to resources and labor. Yam plants (cv. Balbal) were propagated from 30 g tuber head setts and grown for 12 or 20 weeks, with nutrients supplied in the water reservoir to meet demand according to weekly leaf counts. Deficiencies of nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur were induced by reducing supply of the relevant nutrient to one tenth of normal. Deficiencies of iron, boron, manganese, zinc, copper, and molybdenum were induced by omitting the relevant nutrient from the culture medium. After 12 weeks, leaf blades of the main stem were sampled from four positions (immature, young expanded, mid, and old) weighed and analyzed for nutrient concentration, and dry weight of plant parts was recorded. Significant growth reduction was achieved for each deficiency except Fe, Zn, Cu, and Mo, which nonetheless developed some foliar symptoms. Effects on nutrient concentrations in leaves are reported, providing concentrations indicative of adequate and deficient status. Dioscorea esculenta was found to be particularly sensitive to Mn deficiency, although symptom presentation was atypical. Unusually low translocation of phloem‐mobile nutrients was also observed, paralleling reported observations on D. alata.     

Methods for Characterization of Residual Starch in Distiller's Dried Grains with Solubles (DDGS)

The objective of this study was to establish methods for determining the content and components of residual starch in distiller's dried grains with solubles (DDGS), a coproduct from dry‐grind corn ethanol production. Four DDGS prepared in our laboratory and one DDGS obtained from a commercial ethanol manufacturer were used for the study. Quantitative analysis of total residual sugar (TRS) in DDGS was performed by determining d ‐glucose produced by enzymatic hydrolysis of oligosaccharides and residual starch remaining in hexane‐defatted DDGS after being dispersed in 90% DMSO. The TRS consisted of free glucose, oligosaccharides, and residual starch. The commercial manufacturer's DDGS contained more TRS (15.8%, w/w db) than the laboratory‐processed DDGS (2.4–2.9%, w/w db). The content of residual starch remaining in the commercial DDGS (5.5% w/w db) was also larger than the laboratory‐processed DDGS (1.9–2.5% w/w db). Analyses of molecular weight distribution showed that the residual starch in DDGS consisted of short‐chain amylose and amylopectin, respectively, as the major and minor components. The short‐chain amylose molecules constituted 86.5–94.1% of the residual starch. The major population of the short‐chain amyloses had an average degree of polymerization (DP) of 85, closely resembling the length of enzyme‐resistant fragments of amylose‐lipid complexes.     

Assessing the risks of introduced chickens and their pathogens to native birds in the Galápagos Archipelago

Poultry production is an important economic activity on inhabited islands of the Galápagos archipelago. There has been a recent surge in both small-scale backyard chickens and larger scale broiler production associated with growth in the human population and the tourist industry. With increased poultry production, concerns have been expressed about the increasing risk of transfer of disease from chickens to native Galápagos bird species that may have little resistance to introduced pathogens [Wikelski, M., Foufopoulos, J., Vargas, H., Snell, H., 2004. Galápagos birds and diseases: invasive pathogens as threats for island species. Ecology and Society 9(5). Available from: URL:http://www.ecologyandsociety.org/vol9/iss1/art5]. This study evaluates risks posed by chicken disease to endemic and native Galápagos bird species, based on empirical evidence of pathogens present in chickens on the islands and a literature review of effects of these pathogens in wild species. Pathogens identified in domestic chicken populations of immediate avian conservation concern are Newcastle disease, Mycoplasma gallisepticum, and the proventricular parasite Dispharynx sp. Newcastle disease (avian paramyxovirus-1) poses an imminent threat to Galápagos penguins (Spheniscus mendiculus), flightless cormorants (Phalacrocorax harrisi), and lava gulls (Larus fuliginosus), species with very small population sizes (less than 1500 animals each). Additionally, litter from broiler farms could affect ecological processes in local ecosystems. Improved poultry biosecurity measures are urgently needed on the Galápagos Islands for avian disease management, yet developing these strategies presents political, social, and economic challenges.     

Efficiency of a recombinant MSA-2c-based ELISA to establish the persistence of antibodies in cattle vaccinated with Babesia bovis

Bovine babesiosis is caused by Babesia bovis and B. bigemina in Argentina. These protozoans are prevalent north of parallel 30 degrees S, where their natural vector Rhipicephalus (Boophilus) microplus is widespread. To prevent babesiosis outbreaks in endemic areas, an increasing population of 4-10-month-old calves are vaccinated with low virulence B. bovis R1A (BboR1A) and B. bigemina S1A (BbiS1A) strains. In non-endemic areas, an additional calf population is also vaccinated and boostered as adults, before they are relocated to R. microplus-endemic areas of the country. Serological tests are currently utilized not only to determine the status of natural Babesia spp. infections, but also to confirm the infection caused by vaccine strains. For this purpose, an indirect enzyme immunoassay (ELISA) based on the recombinant major surface antigen-2c (rMSA-2c) of B. bovis expressed in Escherichia coli, was standardized using sera from Babesia spp. experimentally infected cattle. ELISA(rMSA-2c) was validated using sera obtained weekly during 336 days from steers primed and boostered with BboR1A and/or BbiS1A on days 0 and 154, then compared with the immunofluorescent-antibody test (IFAT). Western blot (WB) protein analysis was used to confirm the specificity of the immune response to rMSA-2c. The sensitivity and specificity for ELISA(rMSA-2c) were 92 and 96% after the Babesia spp. priming and 88 and 73% after the boostering immunization, respectively. The sensitivity and specificity for IFAT were 99 and 90% after priming and 92 and 98% after boostering, respectively. Unlike IFAT, ELISA(rMSA-2c) detected a remarkable delayed booster response and a significant drop in specificity between 35 and 84 days after the booster immunization. Simultaneously, 87.5% of cattle boostered with B. bigemina showed cross-reactions in the ELISA(rMSA-2c), particularly between 63 and 77 days after the inoculation. A reaction against E. coli was observed, since bands of approximately 40 and/or 42kDa were detected using sera from cattle before and after Babesia spp. inoculations. ELISA(rMSA-2c) showed to be useful between 42 and 98 days after priming with Babesia spp. live vaccine to evaluate the success of infecting cattle. However, after boostering the test showed low specificity.     

Modelling multi-year coupled carbon and water fluxes in a boreal aspen forest

In order to test two hypotheses: (i) that carbon (C) and energy exchanges between terrestrial ecosystems and the atmosphere are closely constrained by soil water availability, and (ii) that vegetation is able to optimize soil water uptake from different soil layers; two model simulations were conducted. The Boreal Ecosystem Productivity Simulator (BEPS) model was run to simulate an aspen forest in Saskatchewan, Canada during the period 1997–2004. In Simulation 1, the effect of soil water availability in different soil layers on stomatal conductance was weighted only by root fraction. In Simulation 2, the influence of soil water availability in different soil layers on stomatal conductance was weighted according to both the root fraction and soil water availability, in order to allow easier access of roots to soil layers containing more water.Comparison against measured fluxes showed that Simulation 2 was an improvement over Simulation 1 in predicting C, water and energy fluxes at different time scales in dry years. In Simulation 1, the daytime C and water fluxes were underestimated during the transition from adequate to insufficient soil water content in the upper layers. In this run, the model captured 92, 79 and 91% of the daily variances in gross primary productivity (GPP), net ecosystem productivity (NEP), and ecosystem respiration (R_e) during 1997–2004. In Simulation 2, the daily variances of GPP, NEP, and R_e explained by the model increased to 93, 82 and 92%, respectively. In Simulation 1, the annual NEP was considerably underestimated in the dry years and years with dry periods, with a root mean square error (RMSE) of 45 g C m⁻² year⁻¹ (n = 8) from 1997 to 2004. In Simulation 2, the RMSE value of simulated annual NEP was reduced to 14 g C m⁻² year⁻¹, a relatively small value compared with the average NEP of 157 g C m⁻² year⁻¹ during 1997–2004. This suggested that the ability of plant roots to extract water from deep soil layers is critical for the forest to maintain growth when surface layers dried out. Our model results showed that NEP was very sensitive to water conditions at this site. In wet years, heterotrophic respiration was enhanced and NEP was reduced.     

No alternative? The politics and history of non-GMO certification

Third-party certification is an increasingly prevalent tactic which agrifood activists use to “help” consumers shop ethically, and also to reorganize commodity markets. While consumers embrace the chance to “vote with their dollar,” academics question the potential for labels to foster widespread political, economic, and agroecological change. Yet, despite widespread critique, a mounting body of work appears resigned to accept that certification may be the only option available to activist groups in the context of neoliberal socio-economic orders. At the extreme, Guthman (Antipode 39(3): 457, 2007) posits that “at this political juncture… ‘there is no alternative.” This paper offers a different assessment of third-party certification, and points to interventions that are potentially more influential that are currently available to activist groups. Exploring the evolution of the Non-GMO Project—a novel certification for foods that are reasonably free of genetically engineered (GE) material—I make two arguments. First, I echo the literature’s critical perspective by illustrating how certification projects become vulnerable to industry capture. Reviewing its history and current context, I suggest that the Non-GMO Project would be better suited to helping companies avoid mounting public criticism than to substantially reorient agrifood production. Second, I explore the “politics of the possible” in the current political economy and argue that while neoliberalization and organizers’ places within the food system initially oriented the group towards the private sector, the choice to pursue certification arose directly from two industry partnerships. Consequently, current trends might favor market mechanisms, but certification is only one possible intervention that has emerged as a result of particular, and perhaps avoidable, circumstances. The article offers tentative delineation of alternatives ways that activists might intervene in agrifood and political economic systems given present constraints.     

Remarks for Stanford Research Institute Conference April 17, 1973

The Noise Control Act of 1972 establishes the first Federal regulatory program to control noise pollution in the U.S. It mandates a three-pronged approach dealing with new products (including motor vehicles), aircraft, and interstate rail and motor carriers. The key challenge now is proper implementation of the legislation by the Environmental Protection Agency. Although the EPA working agenda contains promising implementation plans, and the initial signs were encouraging, recent developments give: cause for concern. Among these are indications of inadequacies in the new product noise criteria being developed, reliance on DOT and FAA personnel to evaluate the performance of their own agencies, and the Administration's hiring ‘freeze’, which hinders the expansion of the EPA's Office of Noise Abatement to a size equal to the task ahead. These and other developments are interpreted in light of the provisions and intent of the Noise Control Act to form the basis of a ‘score card’ for the EPA.