The value of sown grass margins for enhancing soil macrofaunal biodiversity in arable systems

The presence of a grass strip was found to be beneficial to soil macrofauna, increasing the species densities and abundances of earthworms, woodlice and staphylinid beetles. The biodiversity of the three main feeding groups - predators, soil ingesters and litter consumers - was also significantly higher in the grass strips than in the field edges without strips, indicating that establishment of grassy margins in arable fields may enhance ecosystem services such as soil fertility and pest control. The grass strip habitat contained a large number of species of soil macrofauna, being second only to hedgerow habitat, with 10% of the total species list for the farm found only within the margins. Of the rare species recorded on the farm, five of the nine were from the grass strips, four of which were found only there. This study shows that establishing grassy strips in the margins of arable fields increases the biodiversity of the soil macrofauna, both within fields (alpha diversity) and across the farm (beta diversity). (C) 2008 Elsevier B.V. All rights reserved.

The value of arable field margins for enhancing soil macrofaunal biodiversity in agroecosystems

The presence of a grass strip was found to be beneficial to soil macrofauna, increasing the species densities and abundances of earthworms, woodlice and staphylinid beetles. The biodiversity of the three main feeding groups – predators, soil ingesters and litter consumers – was also significantly higher in the grass strips than in the field edges without strips, indicating that establishment of grassy margins in arable fields may enhance ecosystem services such as soil fertility and pest control. The grass strip habitat contained a large number of species of soil macrofauna, being second only to hedgerow habitat, with 10% of the total species list for the farm found only within the margins. Of the rare species recorded on the farm, five of the nine were from the grass strips, four of which were found only there. This study shows that establishing grassy strips in the margins of arable fields increases the biodiversity of the soil macrofauna, both within fields (alpha diversity) and across the farm (beta diversity).

Seeds of change: The value of using Rhinanthus minor in grassland restoration

Question: What is the value of using Rhinanthus minor in grassland restoration and can restrictions on its establishment be overcome? Location: England (United Kingdom). Methods: Two experiments were established to determine the efficacy of inoculating R. minor on a suite of four agriculturally improved grasslands and the efficacy of using R. minor in grassland restoration. In Experiment 1, the effect of herbicide gap creation on the establishment and persistence of R. minor in grasslands ranging in productivity was investigated with respect to sward management. In Exp. 2, R. minor was sown at 1000 seeds/m(2) in conjunction with a standard meadow mix over a randomized plot design into Lolium perenne grassland of moderate productivity. The treatment of scarification was investigated as a treatment to promote R. minor. Results: Gap size had a significant role in the establishment and performance of R. minor, especially the 30 cm diameter gaps (Exp. 1). However, R. minor failed to establish long-term persistent populations in all of the agriculturally improved grasslands. In Exp. 2, establishment of R. minor was increased by scarification and its presence was associated with a significant increase in Shannon diversity and the number of sown and unsown species. Values of grass above-ground biomass were significantly lower in plots sown with R. minor, but values of total above-ground biomass (including R. minor) and forb biomass (not including R. minor) were not affected. Conclusions: The value of introducing R. minor into species-poor grassland to increase diversity has been demonstrated, but successful establishment was dependent on grassland type. The scope for using R. minor in grassland restoration schemes is therefore conditional, although establishment can be enhanced through disturbance such as sward scarification.

Estimating numbers of infectious units from serial dilution assays

The paper concerns the design and analysis of serial dilution assays to estimate the infectivity of a sample of tissue when it is assumed that the sample contains a finite number of indivisible infectious units such that a subsample will be infectious if it contains one or more of these units. The aim of the study is to estimate the number of infectious units in the original sample. The standard approach to the analysis of data from such a study is based on the assumption of independence of aliquots both at the same dilution level and at different dilution levels, so that the numbers of infectious units in the aliquots follow independent Poisson distributions. An alternative approach is based on calculation of the expected value of the total number of samples tested that are not infectious. We derive the likelihood for the data on the basis of the discrete number of infectious units, enabling calculation of the maximum likelihood estimate and likelihood-based confidence intervals. We use the exact probabilities that are obtained to compare the maximum likelihood estimate with those given by the other methods in terms of bias and standard error and to compare the coverage of the confidence intervals. We show that the methods have very similar properties and conclude that for practical use the method that is based on the Poisson assumption is to be recommended, since it can be implemented by using standard statistical software. Finally we consider the design of serial dilution assays, concluding that it is important that neither the dilution factor nor the number of samples that remain untested should be too large.

The expected performance of single nucleotide polymorphism loci in paternity testing

We discuss the utility of single nucleotide polymorphism loci for full trio and mother-unavailable paternity testing cases, in the presence of population substructure and relatedness of putative and actual fathers. We focus primarily on the expected number of loci required to gain specified probabilities of mismatches, and report the expected proportion of paternity indices greater than three threshold values for these loci. (c) 2004 Elsevier Ireland Ltd. All rights reserved.

The use of information technology by the quantity surveying professionals in Hong Kong

This paper introduces the findings of a recent study on the use of information technology (IT) among the quantity surveying (QS) organisations in Hong Kong. The study was conducted through a structured questionnaire survey among 18 QS organisations registered in Hong Kong, representing around 53% of the total number of organisations in the profession. The data set generated from this study provided rich information about what information technology the QS profession used, what the perceived benefits and barriers experienced by the users in the industry were. The survey concluded that although IT had been widely used in QS organisations in Hong Kong, it is mainly used to support various individual tasks of the QS services at a basic level, rather than to streamline the production of QS services as a whole through automation. Most of the respondents agreed that IT plays an important role in the QS profession but they had not fully taken advantage of IT to improve their competitive edge in the market. They usually adopted a more passive “wait and see” approach. In addition, very few QS organisations in Hong Kong have a comprehensive policy in promoting the use of IT within the organisations. It is recommended that the QS profession must recognise the importance of IT and take appropriate actions to meet the challenges of ever-changing and competitive market place.

Educational value of different types of exhibits in an interactive science and technology center

This study analyzes the short-term consequences of visitors' use of different types of exhibits (i.e., "exemplars of phenomena" and "analogy based") together with the factors affecting visitors' understanding of and their evaluation of the use of such exhibits. One hundred and twenty five visitors (either alone or in groups) were observed during their interaction and interviewed immediately afterwards. Findings suggest that the type of exhibit constrains the nature of the understanding achieved. The use of analogical reasoning may lead to an intended causal explanation of an exhibit that is an exemplar of a phenomenon, but visitors often express misconceptions as a consequence of using this type of exhibit. Analogy-based exhibits are often not used as intended by the designer. This may be because visitors do not access the source domain intended; are unaware of the use of analogy per se (in particular, when the exhibit is of the subtype "only showing similarities between relationships"); only acquire fragmentary knowledge about the target; or fail to use analogical reasoning of which they were capable. Furthermore, exhibits related to everyday world situations are recognized to have an immediate educative value for visitors. Suggestions for enhancing the educative value of exhibits are proposed.

Articulation of information requirements for personalised knowledge and construction

The quality of information provision influences considerably knowledge construction driven by individual users’ needs. In the design of information systems for e-learning, personal information requirements should be incorporated to determine a selection of suitable learning content, instructive sequencing for learning content, and effective presentation of learning content. This is considered as an important part of instructional design for a personalised information package. The current research reveals that there is a lack of means by which individual users’ information requirements can be effectively incorporated to support personal knowledge construction. This paper presents a method which enables an articulation of users’ requirements based on the rooted learning theories and requirements engineering paradigms. The user’s information requirements can be systematically encapsulated in a user profile (i.e. user requirements space), and further transformed onto instructional design specifications (i.e. information space). These two spaces allow the discovering of information requirements patterns for self-maintaining and self-adapting personalisation that enhance experience in the knowledge construction process.

iTrench: a study of user reactions to the use of information technology in field archaeology

This article describes work undertaken by the VERA project to investigate how archaeologists work with information technology (IT) on excavation sites. We used a diary study to research the usual patterns of behaviour of archaeologists digging the Silchester Roman town site during the summer of 2007. Although recording had previously been undertaken using pen and paper, during the 2007 season a part of the dig was dedicated to trials of IT and archaeologists used digital pens and paper and Nokia N800 handheld PDAs to record their work. The goal of the trial was to see whether it was possible to record data from the dig whilst still on site, rather than waiting until after the excavation to enter it into the Integrated Archaeological Database (IADB) and to determine whether the archaeologists found the new technology helpful. The digital pens were a success, however, the N800s were not successful given the extreme conditions on site. Our findings confirmed that it was important that technology should fit in well with the work being undertaken rather than being used for its own sake, and should respect established work flows. We also found that the quality of data being entered was a recurrent concern as was the reliability of the infrastructure and equipment.

Defining a framework for the evaluation of information

In any enterprise, decisions need be made during the life cycle of information about its management. This requires information evaluation to take place; a little-understood process. For evaluation support to be both effective and resource efficient, some sort of automatic or semi-automatic evaluation method would be invaluable. Such a method would require an understanding of the diversity of the contexts in which evaluation takes place so that evaluation support can have the necessary context-sensitivity. This paper identifies the dimensions influencing the information evaluation process and defines the elements that characterise them, thus providing the foundations for a context-sensitive evaluation framework.