Crop type influences edge effects on the reproduction of songbirds in sagebrush habitat near agriculture

Extensive fragmentation of the sagebrush shrubsteppe of western North America could be contributing to observed population declines of songbirds in sagebrush habitat. We examined whether habitat fragmentation impacts the reproduction of songbirds in sagebrush edge habitat near agriculture, and if potential impacts vary depending on the adjacent crop type. Specifically, we evaluated whether nest abundance and nest survival varied between orchard edge habitat, vineyard edge habitat, and interior habitat. We then examined whether the local nest predator community and vegetation could explain the differences detected. We detected fewer nests in edge than interior habitat. Nest abundance per songbird was also lower in edge than interior habitat, although only adjacent to vineyards. Nest predation was more frequent in orchard edge habitat than vineyard edge or interior habitat. Predators identified with nest cameras were primarily snakes, however, reduced nest survival in orchard edge habitat was not explained by differences in the abundance of snakes or any other predator species identified. Information theoretic analysis of daily survival rates showed that greater study plot shrub cover and lower grass height at nests were partially responsible for the lower rate of predation-specific daily nest survival rate (PDSR) observed in orchard edge habitat, but additional factors are likely important. Results of this study suggest that different crop types have different edge effects on songbirds nesting in sagebrush shrubsteppe, and that these reproductive edge effects may contribute to observed declines of these species. Habitat managers should avoid the creation of new orchard-sagebrush habitat edges to avoid further impacts on already declining songbird populations.

Quality of tender documents: case studies from the UK

Tendering is one of the stages in construction procurement that requires extensive information and documents exchange. However, tender documents are not always clear in practice. The aim of this study was to ascertain the clarity and adequacy of tender documents used in practice. Access was negotiated into two UK construction firms and the whole tender process for two projects was shadowed for 6-7 weeks in each firm using an ethnographic approach. A significant amount of tender queries, amendments and addenda were recorded. This showed that quality of tender documentation is still a problem in construction despite the existence of standards like Co-ordinated Project Information (1987) and British Standard 1192 (1984 and 1990) that are meant to help in producing clear and consistent project information. Poor quality tender documents are a source of inaccurate estimates, claims and disputes on contracts. Six recommendations are presented to help in improving the quality of tender documentation. Further research is needed into the recommendations to help improve the quality of tender documents, perhaps in conjunction with an industry-wide investigation into the level of incorporation of CPI principles in practice.

Effects of competition on sexual and clonal reproduction of a tunicate: the importance of competitor identity

Individual fitness and the structure of marine communities are strongly affected by spatial competition. Among the most common space holders are the colonial ascidians, which have the ability to monopolize large areas of hard substrate, overgrowing most other competitors. The effects of competition on colony growth and on gonad production of the ascidian Didemnum perlucidum were studied in southeastern Brazil by experimentally removing surrounding competitors. Colonies of D, perlucidum competing for space exhibited a growth rate 9 times less than that of colonies that were competitor free. Among the colonies subject to competition, growth rates were unrelated to the percentage of colony border that was free of competitors. However, the identity of the competitor was important in the outcome of border contacts. At the beginning of the experiment, most border encounters of D. perlucidum were with solitary organisms, which in most cases were overgrown. These were progressively replaced by colonial ascidians and bryozoans, resulting mostly in stand-off interactions. Besides reducing asexual growth, spatial competition also affected female gonad production. Colonies free of competitors had a significantly higher proportion of zooids with ovaries. Thus, our findings show that spatial competition reduces both ascidian colony size and gonad production.

Teachers as bricoleurs : producing plausible readings of curriculum documents

This paper describes teachers as bricoleurs who are professionals engaging in rigorous theoretical work as they construct meaningful assemblages of classroom practice. The author uses examples of two teachers taking up critical literacy discourses in their teaching and conversations to explain the construction of the teacher as bricoleur. Drawing on work by Deleuze and Guattari, a rhizotextual analysis of data is undertaken to explain the connections between the disparate discourses used by the two teachers and the documents of the Queensland English Syllabus. This understanding of the professional work of teachers negates assumptions about teachers as atheoretical and blind followers of departmental policies and curriculum directives. The author concludes with a description of one method for giving teachers the time and reflexive space to theoretically engage with issues surrounding their professional practice.

Reconsidering the scope of the equitable mortgage arising from deposit of title documents

This article examines the underlying fairness of applying equitable security presumptions to the deposit of title documents belonging to third parties. It argues that within such transactions, the focus of the equitable jurisdiction must be upon the intention of the owner of the title documents rather than presumptions arising from the fact of the deposit. It suggests that there is no logic in applying equitable presumptions, founded on the principles of part performance, to infer a security intention in transactions involving third party title documents. The fact that the parties to a loan advance may have intended to create a mortgage between themselves does not mean that the third party owner of the title documents also intended to create a mortgage. In third party transactions, the objectives of the equity jurisdiction are best achieved through a comprehensive assessment of the intention of all parties and the abolition of presumptions based upon the bare fact of title deposit.

Concept learning of text documents

Concept learning of text documents can be viewed as the problem of acquiring the definition of a general category of documents. To definite the category of a text document, the Conjunctive of keywords is usually be used. These keywords should be fewer and comprehensible. A naïve method is enumerating all combinations of keywords to extract suitable ones. However, because of the enormous number of keyword combinations, it is impossible to extract the most relevant keywords to describe the categories of documents by enumerating all possible combinations of keywords. Many heuristic methods are proposed, such as GA-base, immune based algorithm. In this work, we introduce pruning power technique and propose a robust enumeration-based concept learning algorithm. Experimental results show that the rules produce by our approach has more comprehensible and simplicity than by other methods.

Image featuring for retrieval of multimedia documents

The utilization of massive multimedia documents collections, such as multimedia documents in the global Internet, needs search engines which can rank using both text and image evidence. Massive size and (dynamic) nature of collection can make manual indexing prohibitively expensive in such situations. Traditional search engines utilize only text components of multimedia documents. But there are information needs, which require the utilization of image evidence. In this paper, we investigate image-feature for large and heterogeneous collections. Both the nature and complexities of information needs are key elements for an effective retrieval. Retrieval needs that depend on perceptual similarities (as found in art galleries, building architecture) require the utilization of visual cues. In such situations, the retrieval of multimedia document based on image ranking can provide higher effectiveness. Experimental results show that effectiveness of ranking based on image feature can be higher where perceptual similarities are key elements for retrieval than the retrieval effectiveness of algorithms based on text ranking algorithms

Age, growth and reproduction of deepwater dogfishes from southeastern Australia

The productivity of six deepwater dogfishes was investigated by examining their age, growth and reproductive biology. A new method of ageing was developed, and compared with existing techniques. Some species live greater than 50 years, and populations may not sustain commercial fisheries.