Estimating the importance of maternal age, size, and spawning experience to recruitment of Atlantic cod (Gadus morhua)

Empirical studies have demonstrated the importance of maternal characteristics to egg and larval viability in Atlantic cod (Gadus morhua) and other marine teleosts. The effects of these advantages on total reproductive output of individual fish have not yet been studied. A model of an Atlantic cod population was constructed to determine the contribution of offspring by spawners of different spawning experience. First-, second-, and third-time spawners consisted of cod ages 1-9 years old and experienced spawners consisted of ages 10 and 11. Experienced spawners contributed 10.1-12.4 times more offspring surviving to age 1 than did less experienced spawners. Reproductive efforts by first- and second-time spawners were relatively unimportant. These insights are at odds with traditional maximum sustainable yield based management and lax management, both of which favor a population dominated by young breeders and ignore the large per capita production of recruits by experienced spawners. To be managed for biological survival and commercial viability, northwest Atlantic cod will require legal protection to prevent the harvest of these oldest ages of cod.     

What determines irrigation efficiency when farmers face extreme weather events? A field survey of the major wheat producing regions in China

Water availability is a major constraint on grain production in China, therefore, improving irrigation efficiency is particularly important when agriculture faces extreme weather events. This paper first calculates irrigation efficiency with a translog stochastic frontier production function and then investigates what happens when extreme weather events occur via a Tobit model. The estimated results reveal several important features of irrigation practices: i) irrigation efficiency is lower when extreme weather events occur; ii) large variations in irrigation efficiency occur across irrigation facilities; iii) the farm plots exhibit an extreme distribution across efficiency levels; and iv) water-saving techniques, technology adoption, and the maintenance of farmers’ economic resilience are major determinants of irrigation efficiency. Based on these results we propose the following recommendations: i) farmers should balance crop yield and water use; undertake relevant training programs and adopt water-saving techniques; ii) local governments and researchers should help farmers to find the optimal level of irrigation water use based on their own circumstances and provide better water-saving techniques and training programs rather than simply encouraging farmers to invest in irrigation facilities in the most extreme weather years; and iii) the income level of farm households should be increased so as to improve their resilience to natural disasters.     

Germination of Wheat: A Functional Proteomics Analysis of the Embryo

Germination in the soft wheat (Triticum aestivum L.) cultivar Rosella was followed for three days after imbibition by proteomic analysis of the germ tissue. Two‐dimensional electrophoresis was performed in triplicate for proteins extracted from embryos dissected from mature grain and from grains germinated for 1, 2, and 3 days. For this period, 63 proteins (in 86 spots) in the germ were identified as decreasing in abundance, 35 proteins (in 60 spots) as increasing in abundance, and 28 proteins (in 39 spots) as exhibiting no significant abundance change. Proteins with significant abundance changes are discussed in relation to physiology; these include proteases, amylases and amylase inhibitors, enzymes in lipid metabolism, proteins related to water stress, cell wall hydrolases, oxalate oxidase, and H⁺‐ATPases. Functions associated with proteins synthesized during the germination period are inconsistent with the embryo of mature grain being fully primed for germination.     

Homegardening as a panacea: A case study of South Tarawa

The Republic of Kiribati is a small, highly infertile Pacific Island nation and is one of the most challenging locations to attempt to support dense urban populations. Kiribati, like other nations in the Pacific, faces an urban future where food insecurity, unemployment, waste management and malnutrition will become increasing issues. Homegardening is suggested as one way to address many of these problems. However, the most recent study on agriculture production in urban centres in Kiribati shows that, in general, intensive cultivation of homegardens is not a common practice. This disparity between theory and practice creates an opportunity to re‐examine homegardening in Kiribati and, more broadly, in the Pacific. This paper examines the practice of homegardening in urban centres in Kiribati and explores reasons why change has or has not occurred through interviews with homegardeners and government/donor representatives. Results show that homegardening has increased significantly in the past five years, largely because of the promotion of homegardens and organic composting systems by donor organisations. While findings further endorse homegardening as an excellent theoretical solution to many of the problems that confront urban settlements in Kiribati and the Pacific, it raises additional questions regarding the continuation of homegarden schemes beyond donor support programmes.     

Coordination polymers of osmium: the nature of osmium black

The design of cytochemical reagents that yield osmiophilic products from which an osmium black may be derived on exposure to osmium tetroxide has resulted in new methods described previously for the ultrastructural demonstration of enzyme activity and functional groups of macromolecules with the electron microscope. Attempts to determine the nature of the osmium black end products have been frustrated by their insolubility. The preparation of watersoluble analogs and their characterization as polymers suggest that the insoluble osmium blacks are coordination polymers. This is consonant with the unusually favorable properties of osmium black in electron microscopy. Although polymers of osmium have frequently been postulated as the end products of reaction of osmium tetroxide with tissue conistituents or with other organic compounds, this is the first example of their characterization.     

Activity of mesotrione on resistant weeds in maize

Mesotrione is a new callistemone herbicide that inhibits the HPPD enzyme (p-hydroxyphenylpyruvate dioxygenase) and introduces a new naturally selective tool into weed-management programmes for use in maize. Mesotrione provides control of the major broad-leaved weeds, and it can be used in integrated weed-management programmes depending on the grower's preferred weed-control strategy. At post-emergence rates of 150 g AI ha-1 or less, mesotrione provides naturally selective control of key species that may show triazine resistance (TR), e.g. Chenopodium album L, Amaranthus species, Solanum nigrum L, as well as species of weed that show resistance to acetolactase synthase (ALS) inhibitors e.g. Xanthium strumarium L, Amaranthus spp and Sonchus spp. The data presented show that resistant and susceptible biotypes of these species with resistance to triazine herbicides, such as atrazine, simazine, terbutylazine and metribuzin, or ALS-inhibitor herbicides, such as imazethepyr, remain susceptible to mesotrione. These results confirm that there is no cross-resistance in biotypes with target site resistance to triazine or ALS-inhibiting herbicides. It is important that herbicide choice and rotation becomes an integral part of planning weed management, so as to minimise the risks of crop losses from weed competition, build-up of weed seed in the soil and the further development of weed resistance across a range of herbicide modes of action.     

Genotype and Environmental Influences on Pasting Properties of Rice Flour

The pasting behavior of flour from several Australian rice (Oryza sativa L.) cultivars, differing in amylose content and grown in three different locations and three seasons, were determined using the Rapid Visco Analyser. Genotype, growth season, and growth location all affected the pasting behavior of rice flour. The amylose content of the same cultivar was significantly higher in the coolest growing season, resulting in RVA traces with lower peak viscosity and higher setback than samples with lower amylose content. When the same cultivar of rice was grown in different locations in the same season, there were no significant differences in the total starch, protein, lipid, and amylose content of the flour, but there were significant differences in the pasting behavior. This indicates that environmental as well as genetic factors influence the pasting behavior of rice flour. Flour from parboiled and quick‐cooking rice did not paste and had low viscosities compared with unprocessed rice. Results from this study showed that the pasting behavior of rice flour was related to genotype and was influenced by environmental factors that brought about subtle changes in the grains that were not picked up by chemical analyses.     

The role of sand lances (Ammodytes sp.) in the Northwest Atlantic Ecosystem: A synthesis of current knowledge with implications for conservation and management

The American sand lance (Ammodytes americanus, Ammodytidae) and the Northern sand lance (A. dubius, Ammodytidae) are small forage fishes that play an important functional role in the Northwest Atlantic Ocean (NWA). The NWA is a highly dynamic ecosystem currently facing increased risks from climate change, fishing and energy development. We need a better understanding of the biology, population dynamics and ecosystem role of Ammodytes to inform relevant management, climate adaptation and conservation efforts. To meet this need, we synthesized available data on the (a) life history, behaviour and distribution; (b) trophic ecology; (c) threats and vulnerabilities; and (d) ecosystem services role of Ammodytes in the NWA. Overall, 72 regional predators including 45 species of fishes, two squids, 16 seabirds and nine marine mammals were found to consume Ammodytes. Priority research needs identified during this effort include basic information on the patterns and drivers in abundance and distribution of Ammodytes, improved assessments of reproductive biology schedules and investigations of regional sensitivity and resilience to climate change, fishing and habitat disturbance. Food web studies are also needed to evaluate trophic linkages and to assess the consequences of inconsistent zooplankton prey and predator fields on energy flow within the NWA ecosystem. Synthesis results represent the first comprehensive assessment of Ammodytes in the NWA and are intended to inform new research and support regional ecosystem‐based management approaches.     

Characterization of gp41 as the transmembrane protein coded by the HTLV-III/LAV envelope gene

Radiolabeled amino acid sequencing was used to characterize gp41, an antigen of HTLV-III/LAV, the virus believed to be the etiological agent of the acquired immune deficiency syndrome. This antigen is the one most commonly detected in immunoblot assays by sera of patients with AIDS or AIDS-related complex (ARC) and other individuals infected with HTLV-III/LAV. A mouse monoclonal antibody that was reactive with gp41 precipitated a 160-kilodalton protein (gp160) in addition to gp41, but did not precipitate a 120-kilodalton protein (gp120) from extracts of metabolically labeled cells producing HTLV-III. Extracts of infected cells that had been labeled with tritiated leucine or isoleucine were immunoprecipitated with the monoclonal antibody. The immunoprecipitates were fractionated by polyacrylamide gel electrophoresis and the p41 was eluted from the gel bands and subjected to amino-terminal radiolabeled amino acid sequencing by the semiautomated Edman degradation. Leucine residues occurred in cycles 7, 9, 12, 26, 33, and 34 among 40 cycles and isoleucine occurred in cycle 4 among 24 cycles analyzed. Comparison of the data with the deduced amino acid sequence of the env gene product of HTLV-III precisely placed gp41 in the COOH-terminal region of the env gene product. Gp160 is thus the primary env gene product and it is processed into gp120 and gp41.