University of Stirling

About: University of Stirling is a education organization based out in Stirling, Stirling, United Kingdom. It is known for research contribution in the topics: Population & Context (language use). The organization has 7722 authors who have published 20549 publications receiving 732940 citations. The organization is also known as: Stirling University.

Biological "bar codes" in human faces

Abstract: The structure of the human face allows it to signal a wide range of useful information about a person's gender, identity, mood, etc. We show empirically that facial identity information is conveyed largely via mechanisms tuned to horizontal visual structure. Specifically observers perform substantially better at identifying faces that have been filtered to contain just horizontal information compared to any other orientation band. We then show, computationally, that horizontal structures within faces have an unusual tendency to fall into vertically co-aligned clusters compared with images of natural scenes. We call these clusters "bar codes" and propose that they have important computational properties. We propose that it is this property makes faces "special" visual stimuli because they are able to transmit information as reliable spatial sequence: a highly constrained one-dimensional code. We show that such structure affords computational advantages for face detection and decoding, including robustness to normal environmental image degradation, but makes faces vulnerable to certain classes of transformation that change the sequence of bars such as spatial inversion or contrast-polarity reversal.

Primary Lowland Dipterocarp Forest at Danum Valley, Sabah, Malaysia: Structure, Relative Abundance and Family Composition

Abstract: Trees greater than or equal to 10 cm gbh were enumerated, mapped and identified in two 4 hectare (ha) (40 000 m 2 ) plots in 1985-1987. The number of species recorded was 511 (in 164 genera and 59 families) in a total sample of 17 985 individuals. Plots 1 and 2 contain 388 and 387 species respectively, and for trees greater than or equal to 30 cm gbh there are 247 and 242 species. Relative abundance patterns were fitted to a logseries distribution. In each plot, 51% of species are rare ( f f = 1). Common species ( f ≥ 5 ) achieve a minimum area at 2 ha. The plots are close ‘replicates’ in many respects, and 8 ha gives an adequate sample. The mean density of trees greater than or equal to 10 cm gbh and 30 cm gbh is 2248 ha -1 and 470 ha -1 , with corresponding basal areas of 30.7 m 2 ha -1 and 26.6 m 2 ha -1 . The linear relation between In frequency and In gbh, the small (0.5% ) ground area of gaps, and the low contribution by pioneer species show little recent disturbance. Dominance by 2-4 understorey species is pronounced. For trees greater than or equal to 30 cm gbh, the Euphorbiaceae contribute the most to density at 21% , with Dipterocarpaeceae second at 16%: corresponding basal areas are 7% and 49% . For trees greater than or equal to 10 cm gbh, density of the Euphorbiaceae reaches 28% , Dipterocarpaceae 9% , followed by Annonaceae 8% , Lauraceae 7% and Meliaceae 6% . Lauraceae was the most species-rich family (83 species), then Euphorbiaceae (51 species) and Meliaceae (36 species). Compared with the means of nine other sites in this forest type, Danum has 84% of the density and 74% of the basal area for trees greater than or equal to 30 cm gbh; and 60% of the species richness for this size class on a 1-1.6 ha basis. The forest is differentiated by its dominance by Euphorbiaceae, in terms of tree density, and the high contributions made by Lauraceae and Meliaceae. These attributes may reflect special site conditions and/or a late stage in recovery from past disturbance.

Dissimilatory reduction and transformation of ferrihydrite-humic acid coprecipitates.

Abstract: Organic matter (OM) is present in most terrestrial environments and is often found coprecipitated with ferrihydrite (Fh). Sorption or coprecipitation of OM with Fe oxides has been proposed to be an important mechanism for long-term C preservation. However, little is known about the impact of coprecipitated OM on reductive dissolution and transformation of Fe(III) (oxyhydr)oxides. Thus, we study the effect of humic acid (HA) coprecipitation on Fh reduction and secondary mineral formation by the dissimilatory Fe(III)-reducing bacterium Shewanella putrefaciens strain CN32. Despite similar crystal structure for all coprecipitates investigated, resembling 2-line Fh, the presence of coprecipitated HA resulted in lower specific surface areas. In terms of reactivity, coprecipitated HA resulted in slower Fh bioreduction rates at low C/Fe ratios (i.e., C/Fe ≤ 0.8), while high C/Fe ratios (i.e., C/Fe ≥ 1.8) enhanced the extent of bioreduction compared to pure Fh. The coprecipitated HA also altered the secondary Fe mineralization pathway by inhibiting goethite formation, reducing the amount of magnetite formation, and increasing the formation of a green rust-like phase. This study indicates that coprecipitated OM may influence the rates, pathway, and mineralogy of biogeochemical Fe cycling and anaerobic Fe respiration within soils.

Corporate Mergers and Shareholder Wealth Effects: 1977-1986

Abstract: The paper investigates the distribution of returns to shareholders of UK companies involved in acquisitions during the period 1977-1986 Three control models were used in the analysis: the market model with parameters identified through OLS regression, a model based on adjusted betas, and finally an index-relative model Abnormal returns were identified around both bid announcement and outcome dates for bidders and targets in completed and abandoned bids Examination was also made of the distribution of wealth changes for bidders and targets separately and for both in combination The results demonstrate that, although there is no net wealth decrease to shareholders in total as a result of takeover activity, shareholders of bidder firms do suffer wealth decreases By contrast, shareholders in target firms obtained significant, positive wealth increases in both completed and abandoned bids