Environmental fate of pesticides used in Australian viticulture IV. Aqueous stability of dithianon

Dithianon formulations are unstable in slightly basic aqueous solutions (pH 9, 20°C, t _½ = 5.6 h) but relatively stable in neutral or acidic solution (pH 4,20°C, t _½ = 6443 h). To ensure the efficacy of this fungicide it is important to prepare the spray mix fresh with neutral or slightly acidic water. Dithianon is unstable towards natural sunlight in the solid and aqueous phase, with half‐lives of approximately 68 and 42 days, respectively. Thermal hydrolysis does not seem to be the preferred degradation pathway when aqueous solutions are heated by the South Australian summer sun. The major aqueous phase photodegradation product has been identified as 2,3‐dihydro‐1,4‐dithiaanthraquinone. These results strongly suggest that should dithianon be accidentally released into basic Australian waters then it is likely to be rapidly chemically hydrolysed and pose little long term environmental threat. However, dithianon is only slowly chemically and photo‐lytically hydrolysed in neutral and acidic waters, and in this case accidentally release may pose a significant short term environmental threat.     

Round your numbers in rank tests: exact and asymptotic inference and ties

Non-parametric statistical tests are commonly used in the behavioral sciences. Researchers need to be aware that non-parameteric methods involving ranks can perform unreliably as a result of very small amounts of noise added in the storage and manipulation of values by computers, causing spurious reduction in the number of ties. In order to avoid this problem, researchers should round values to an appropriate number of decimal places prior to the ranking procedure to ensure that data points whose values cannot be separated according to the precision of their measurement are recorded as having identical rank. We also recommend exact rather than asymptotic evaluation of p values in non-parametric statistical tests.     

Relating characteristics of global biodiversity targets to reported progress

To inform governmental discussions on the nature of a revised Strategic Plan for Biodiversity of the Convention on Biological Diversity (CBD), we reviewed the relevant literature and assessed the framing of the 20 Aichi Biodiversity Targets in the current strategic plan. We asked international experts from nongovernmental organizations, academia, government agencies, international organizations, research institutes, and the CBD to score the Aichi Targets and their constituent elements against a set of specific, measurable, ambitious, realistic, unambiguous, scalable, and comprehensive criteria (SMART based, excluding time bound because all targets are bound to 2015 or 2020). We then investigated the relationship between these expert scores and reported progress toward the target elements by using the findings from 2 global progress assessments (Global Biodiversity Outlook and the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services). We analyzed the data with ordinal logistic regressions. We found significant positive relationships (p < 0.05) between progress and the extent to which the target elements were perceived to be measurable, realistic, unambiguous, and scalable. There was some evidence of a relationship between progress and specificity of the target elements, but no relationship between progress and ambition. We are the first to show associations between progress and the extent to which the Aichi Targets meet certain SMART criteria. As negotiations around the post-2020 biodiversity framework proceed, decision makers should strive to ensure that new or revised targets are effectively structured and clearly worded to allow the translation of targets into actionable policies that can be successfully implemented nationally, regionally, and globally.     

How sensitive are elasticities of long-run stochastic growth to how environmental variability is modelled?

A variable environment leaves a signature in a population's dynamics. Deriving statistical and mathematical models of how environmental variability affects population projections has - in the wake of reports of substantial climatic fluctuations - received much recent attention. If the model changes, then so too does the population projection. This is because a different model of environmental variability changes estimates of long-run stochastic growth, which is a function of demographic rates and their temporal sequence. Decomposing elasticities of long-run stochastic growth into constituent parts can assess the relative influence of different components. Here, we investigate the consequences of changing the environmental state definition, and therefore altering the shape of demographic rate distributions and their temporal sequence, by using age-structured matrix models to project vertebrate populations into the future under a range of environmental scenarios. The identity of the most influential demographic rate was consistent among all approaches that perturbed only the mean, but was not when only the variance was perturbed. Furthermore, the influence of each demographic rate fluctuated among projections by up to factors of six and two for changes to the variance and mean, respectively. These changes in influence depend in part upon how environmental variability - in particular, the color of environmental noise - is incorporated. In the light of predictions of increasing climatic variability in the future, these results suggest caution when drawing quantitative conclusions from stochastic population projections.     

Understanding yields in alley cropping maize (Zea mays L.) and Cassia siamea Lam. under semi-arid conditions in Machakos, eastern Kenya

ＩｎｔｒｏｄｕｃｔｉｏｎＯｎｌｙａｂｏｕｔ 2 0 %ｏｆＫｅｎｙａ’ｓｔｏｔａｌｌａｎｄａｒｅａｈａｓｈｉｇｈｐｏｔｅｎｔｉａｌｆｏｒａｇｒｉｃｕｌｔｕｒａｌｐｒｏｄｕｃｔｉｏｎ ,ｔｈｅｒｅｓｔｂｅｉｎｇａｒｉｄｏｒｓｅｍｉ ａｒｉｄ .ＴｈｅａｎｎｕａｌｐｏｐｕｌａｔｉｏｎｇｒｏｗｔｈｒａｔｅｉｎＫｅｎｙａｏｆｃｌｏｓｅｔｏ 4 %ｉｓｏｎｅｏｆｔｈｅｈｉｇｈｅｓｔｉｎｔｈｅｗｏｒｌｄ (ｅ .ｇ .ＵｎｉｔｅｄＮａｔｉｏｎｓＤｅｖｅｌｏｐｍｅｎｔＰｒｏｇｒａｍｍｅ ,1990 ) .Ｔｈｉｓｓｉｔｕａｔｉｏｎｈａｓｌ…     

Leaf area development, dry weight accumulation and solar energy conversion efficiencies of Phaseolus vulgaris L. under different soil moisture levels near Nairobi, Kenya

ＩｎｔｒｏｄｕｃｔｉｏｎＫｅｎｙａ○ｓｈｉｇｈｐｏｐｕｌａｔｉｏｎｇｒｏｗｔｈｒａｔｅｈａｓｃｒｅａｔｅｄｐｒｅｓｓｕｒｅｏｎｔｈｅｈｉｇｈｐｏｔｅｎｔｉａｌａｒｅａｓ．Ｔｈｉｓｈａｓｒｅｓｕｌｔｅｄｉｎｔｈｅｍｉｇｒａｔｉｏｎｏｆｐｅｏｐｌｅｔｏｕｎｃｕｌｔｉｖａｔｅｄ“ｍａｒｇｉｎａｌ”ｌａｎｄｓｗｈｉｃｈｍａｋｅｕｐａｂｏｕｔ８０％ｏｆｔｈｅｃｏｕｎｔｒｙａｎｄａｒｅｐｒｅｄｏｍｉｎａｎｔｌｙｏｆｌｏｗａｇｒｉｃｕｌｔｕｒａｌｐｒｏｄｕｃｔｉｖｉｔｙ（Ｈｏｒｎｅｔｚ，１９９０）．Ｔｈｅｓｅ…     

Reassessing the role of the honeybee (Apis mellifera) Dufour's gland in egg marking

Dufour's gland secretion may allow worker honeybees to discriminate between queen-laid and worker-laid eggs. To investigate this, we combined the chemical analysis of individually treated eggs with an egg removal bioassay. We partitioned queen Dufour's gland into hydrocarbon and ester fractions. The bioassay showed that worker-laid eggs treated with either whole gland extract, ester fraction or synthetic gland esters were removed more slowly than untreated worker-laid eggs. However, the effect only lasted up to 20 h. Worker-laid eggs treated with the hydrocarbon fraction were removed at the same rate as untreated eggs. The amount of ester which reduced the egg removal rate was far higher than that naturally found on queen-laid or worker-laid eggs, and at natural ester levels no effect was found. Our results indicate that esters or hydrocarbons probably do not function as the signal by which eggs can be discriminated.     

Sediment quality guidelines: challenges and opportunities for improving sediment management

During the International Conference on Deriving Environmental Quality Standards for the Protection of Aquatic Ecosystems held in Hong Kong in December 2011, an expert group, comprising scientists, government officials, and consultants from four continents, was formed to discuss the important scientific and regulatory challenges with developing sediment quality guidelines (SQGs). We identified the problems associated with SQG development and made a series of recommendations to ensure that the methods being applied were scientifically defensible and internationally applicable. This document summarizes the key findings from the expert group. To enable evaluation of current SQG derivation and application systems, a feedback mechanism is required to communicate confounding factors and effects in differing environments, while field validation is necessary to gauge the effectiveness of SQG values in sediment quality assessments. International collaboration is instrumental to knowledge exchange and method advancement, as well as promotion of ‘best practices’. Since the paucity of sediment toxicity data poses the largest obstacle to improving current SQGs and deriving new SQGs, a standardized international database should be established as an information resource for sediment toxicity testing and monitoring data. We also identify several areas of scientific research that are needed to improve sediment quality assessment, including determining the importance of dietary exposure in sediment toxicity, mixture toxicity studies, toxicity screening of emerging chemicals, how climate change influence sediments and its biota, and possible use of new toxicity study approaches such as high throughput omic-based toxicity screenings.     

Linking chemical extraction to microbial degradation of 14C-hexadecane in soil

Chemical extractions have been shown to measure the biodegradable fraction of aromatic contaminants in soil; however, there is little research on the chemical prediction of aliphatic hydrocarbon degradation. The aim of this study was to investigate the potential for cyclodextrin extractions to predict hexadecane biodegradation in soil. Soils were amended with 10 or 100 mg kg⁻¹ of a model alkane n-hexadecane and 100 Bq g⁻¹¹⁴C-n-hexadecane. Correlations between the extents of mineralisation and extractions of the ¹⁴C-contaminant were determined. Solvent shake extractions and aqueous CaCl₂ extractions were poor predictors of hexadecane bioaccessibility. However, the novel HP-α-CD shake extraction showed close correlation (r² = 0.90, n = 36, p < 0.05) to the mineralisation data. This novel extraction technique has the potential to be used to assess the biodegradable aliphatic hydrocarbon fraction in contaminated soils.