Ergonomics and safety of manual bag sealing.

A variety of seals is used to close bags. Each seal has advantages and disadvantages. For shop assistants sealing bags could be a repetitive physically demanding action. Opening and closing the bags again can cause some discomfort or annoyance for consumers. Besides, it is an activity which can endanger safety, i.e., knives being used in opening, children swallowing the systems of sealing. To prevent these problems a new sealing system was developed. In this paper the opinion of shop assistants, consumers and experts on several bag sealing systems was studied. It appeared that for sealing plastic bags, adhesive tape with paper is the best out of 4 systems, closely followed by adhesive tape. It is discussed that for the elderly, there is still room for improvement in opening bag seals.     

Influence of host plants on sexual communication in the herbivorous bug Lygocoris pabulinus

Summary. Host plant volatiles may be involved in the sexual communication of insects in several ways. In the pheromone-producing sex, these volatiles may affect pheromone production or release and, in the receptive sex, plant volatiles may have a synergistic effect on the attraction to sex pheromone. We conducted three types of experiments to determine if and how plant volatiles are involved in the sexual communication of Lygocoris pabulinus (L.) (Heteroptera: Miridae), the females of which attract males. In a one-choice cylinder bioassay, females were offered to males on two different plants, belonging to different plant families, i.e. potato leaves and goosefoot leaves, to determine if specific plant volatiles were involved in the attraction of males towards females. Females on potato leaves were as attractive as females on goosefoot leaves, but significantly more attractive than females without plant material. The latter result suggests an interaction between females and potato leaves. However, in two-choice flying and walking bioassays, using delta traps in a wind tunnel and a vertical Y-track olfactometer, males were attracted to females irrespective of the presence of potato leaves. This difference in result is probably due to the fact that in the latter assays females were confined with pollen as an alternative food source, while females in the one-choice assay had access to water only, so that they may have suffered from malnutrition. Males in the one-choice assay were also attracted to potato leaves from which females had been removed, indicating that attractive components from females are deposited and adsorbed to the substrate. Plants are probably only indirectly involved in sexual communication, their surface merely functioning as a substrate from which pheromone is released. Males may subsequently be attracted to such plants or substrates. Clean plant material was not attractive to L. pabulinus males, hence plant volatiles alone do not seem to be used by these males as possible mate location cues.     

A harvest failure approach to assess the threat from an invasive species

We present the idea of using potential infringements on annual allowable harvest targets as an approach to estimate threats from invasive species to the forest products sector. The approach uses present-day harvest levels as a reference level to estimate when and where the impact of a nonnative forest pest could become economically damaging. We use a generic model that simulates spread and damage by nonnative invasive species, basic harvest and forest growth through time. The concept is illustrated with a case study of a new nonnative invasive pest, Sirex noctilio Fabricius on pine resources in eastern Canada. Impacts of invasion on wood supply, in particular, the point at which present-day harvest levels are not attainable, were identified for 77 non-overlapping geographical regions that delimit the primary wood supply areas around large mills and wood processing facilities in eastern Canada. The results identify the minimum area of a pest outbreak that could trigger harvest shortages (approximately 12.5–14 M ha of pine forests in Ontario and Quebec). Beyond this level, the amount of host resource available for harvesting in any given year declines rapidly. The failure to sustain broad-scale harvest targets may be an attractive and intuitive indicator for policy makers and regulators interested in developing control and “slow-the-spread” programs for non-native forest pests.     

The kinetics of reductive dehalogenation of a set of halogenated aliphatic hydrocarbons in anaerobic sediment slurries

Disappearance rate constants are reported for the reductive transformation of 17 halogenated aliphatic hydrocarbons in anaerobic sediment-water samples. Statistical experimental design in combination with multivariate chemical characterization of their chemical properties was used to select the compounds. Degradation followed pseudo first-order kinetics through at least two half-lives for 15 of the 17 compounds. Of all the compounds investigated, 1,2,3-trichloropropane and dichloromethane were unique in that they were dehalogenated according to zero-order kinetics. Reductive dehalogenation was the sole transformation reaction taking place.     

Socio-cognitive constraints and opportunities for sustainable intensification in South Asia: insights from fuzzy cognitive mapping in coastal Bangladesh

Environment, Development and Sustainability - Appreciating and dealing with the plurality of farmers’ perceptions and their contextual knowledge and perspectives of the functioning and...     

Chemical composition and liberation characterization of printed circuit board comminution fines for beneficiation investigations

Chemical composition and liberation are critical attributes in characterizing a resource stock for beneficiation investigations. Though end-of-life printed circuit board is recognized as a valuable secondary resource stock, no procedural standard exists for the determination of its chemical composition, nor for the ?75 μm fines generated during its comminution. The effect of the digestion procedure on the final assays in wet spectroscopic analyses was assessed in this work. Liberation was also explored against literature background. Determination of assays of all constituent elements in printed circuit board comminution fines was found to require comparison of data from more than one digestion condition, while composite particles still persist at the fines sizes, though very few. The discussion reflects how these impact the beneficiation investigations.