Biotic homogenization in an increasingly urbanized temperate grassland ecosystem

Question: How does urbanization and associated declines in fire frequency alter the floristic composition of native temperate grasslands? Does it lead to: (1) biotic homogenization, i.e. compositional similarity between remnants increases; (2) biotic differentiation, whereby similarity between remnants declines, or; (3) clustered differentiation, where similarity between remnants remainsunchanged, but composition shifts from the historical state?Location: Victoria, Australia.Methods: Using site-level surveys, we examined changes in the floristic similarity of 29 urban grasslands from 1992 to 2013 and compared these changes to those of 63 rural grasslands from 1989 to 2014. Community-level changes in the representation of key functional traits were also examined in urban grasslands, with traits advantaged following disturbance regime change and urbanfragmentation predicted to increase in frequency. Results: Our results supported the biotic homogenization hypothesis in urban grasslands. Compositional similarity between grasslands increased principally because of an increase in commonly shared non-native species, with change in native composition comparatively minor. However, no evidence of biotic homogenization was found in rural grasslands, with no significant change in overall composition identified. The most urbanized sites had the highest number of non-native species in both the current and historical data sets, yet non-native composition over the past two decades changed the most in sites on the urban fringe, becoming more similar to sites closer to the urban core. As expected, following declines in fire frequency and increased urbanization, the overall composition of urban grasslands shifted to taller plant species, while native speciescapable of vegetative reproduction and exotic species with an annual life spanincreased in frequency.Conclusion: Urbanization was an important driver of biodiversity change in the investigated system, with increasing competition intensity in response to disturbance regime change a likely cause of biotic homogenization. Our results demonstrate that non-native species are a key driver of biotic homogenization,emphasizing the importance of managing non-native immigration and maintaininghistorical disturbance processes once native ecosystems become urbanized

Subcortical lesions after transient thread occlusion in the rat: T2-weighted magnetic resonance imaging findings without corresponding sensorimotor deficits

Purpose: To investigate infarct evolution and functional consequences of exclusive subcortical or cortico-subcortical strokes, transient middle cerebral artery occlusion (MCAO) was conducted in Wistar rats. Materials and Methods: MCAO was induced in male Wistar rats (260-300 g) for 60 minutes. Lesion volumes and absolute T2 times on magnetic resonance imaging (MRI) were assessed 1 and 14 days after MCAO using a 4.7-T MRI animal scanner in conjunction with functional testing (adhesive tape removal, cylinder test, and ledged beam walking). Results: Functional test scores were not distinguishable between sham-operated animals (N = 5) and those with exclusive caudoputaminal infarct (N = 8; group cp), but showed significant deficits in animals with cortico-subcortical infarction (N = 10; group cp+). The cp group had lower absolute T2 times and a more pronounced reduction in T2 lesion volume over time than the subcortical component in the cp+ group. There was no correlation of T2lesion size or absolute T2 times and functional impairment in either group. Conclusion: When judged from functional tests alone, subcortical ischemic lesions may not be diagnosed reliably. Furthermore, T2-weighted (T2-W) MRI does not well anticipate functional deficits in primarily striatal lesions

Subcortical lesions after transient thread occlusion in the rat: T-2-weighted magnetic resonance imaging findings without corresponding sensorimotor deficits

(c) 2005 Wiley-Liss, Inc

Efficient stem cell labeling for MRI studies

Copyright (c) 2008 John Wiley & Sons, Ltd

Evaluation of moisture characteristics of warm mix asphalt involving natural zeolite

In last decades, warm mix asphalt (WMA) has become a significant alternative paving technology to hot mix asphalt (HMA), due to the relatively low temperatures required to heat asphalt during production and placement, minimising environmental damage while maintaining the advantages of HMA. However, low production and placement temperatures may result moisture-induced damage of asphalts. The objective of this study was to evaluate the moisture susceptibility characteristics of asphalts containing natural zeolite and its comparison with synthetic zeolite, organic, and chemical WMA additives. The stripping properties and moisture susceptibility characteristics of the specimens have been evaluated by means of the Nicholson stripping test and modified Lottman test, respectively