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Individual Strategies (individual + strategy)

Distribution by Scientific Domains

Life Sciences	50%

Selected Abstracts

Distribution, abundance, and individual strategies: a multi-scale analysis of dasyurid marsupials in arid central Australia

ECOGRAPHY, Issue 3 2006
Adele S. Haythornthwaite
We investigated the effects of different environmental factors on the distribution and abundance of 6 species of dasyurid marsupials using a multiple-scale analysis. Data collected in the spinifex dunefields of the Simpson Desert, Australia, were analysed at 3 spatial scales spanning more than 5 orders of magnitude: "metasite" (covering an area of 1000,2000 km2), site (2,12 km2) and grid (0.01 km2). Temporal variability was also investigated, using data collected in March, April, and May in 4 consecutive years from 1997 to 2000. Both abiotic and biotic factors influenced the capture rates of different species at different times and spatial scales. At the coarsest spatial scale, Dasycercus cristicauda (mulgara) was consistently limited in its distribution by the intensity of rainfall, probably as an indirect result of increased grazing pressure from pastoral activity and a higher density of feral predators in high rainfall areas. However, at the finest spatial scale, this partly carnivorous species was scarce in areas of dense spinifex, perhaps because such habitats yield lowest returns during foraging, and was more common in areas where small invertebrate prey were abundant. Factors affecting the distribution of the most abundant dasyurid species in the study area, Sminthopsis youngsoni (lesser hairy-footed dunnart), could not be identified at any scale; we conclude that this reflects the opportunistic foraging strategies and flexible habitat requirements of this insectivorous species. Both Ningaui ridei (wongai ningaui) and Sminthopsis hirtipes (hairy-footed dunnart) were less abundant throughout the study region. For N. ridei, a spinifex specialist, predictors of occurrence could be identified only at the finest scale of analysis; at the grid level, a close positive association was detected in 2 of the 4 study years between capture rate and spinifex cover. For S. hirtipes, all 3 levels of spatial analysis revealed a negative association between capture rate and both rainfall and spinifex density. For the rarely-caught S. crassicaudata (fat-tailed dunnart) and Planigale tenuirostris (narrow-nosed planigale), no clear results were obtained at any spatial scale, and we interpret this to indicate that the study region represents sub-optimal habitat for these species. Given that different factors affected the distribution and abundance of dasyurids at different spatial scales over time, we conclude that a multiple-scale approach to population and community analysis is vital to accurately identify which environmental processes shape population and community dynamics. Understanding the interplay between regional and local processes will be crucial for management of existing species populations and for prediction of their distributions and abundances in future. [source]

Numerical simulation of canine bodily movement

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 2 2010
Yingli Qian
Abstract The aim of this study was to develop finite element (FE) models to simulate bodily movement of an orthodontic treatment of mandibular canine with decayed loads during a therapy period (4 weeks). The normal strain of periodontal ligament was assumed as the key mechanical stimulus for the surface bone remodeling. During the simulation processes, changes in tooth position and in the geometry of the tooth supporting structures and the decayed loads were taken into account. In this numerical simulation, the tooth movement displacements were 1.00,mm in the end of the therapy. The results of the simulation were similar to the observed in clinical studies. It was acceptable to simulate clinical tooth movements by FE method based on these mechanical assumptions. Such a numerical simulation would allow the understanding of tooth movements and help in better planning of individual strategies. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Cooperative Strategy Training and Oral Interaction: Enhancing Small Group Communication in the Language Classroom

MODERN LANGUAGE JOURNAL, Issue 2 2006
DIANE NAUGHTON
This study focused on the effect of a cooperative strategy training program on the patterns of interaction that arose as small groups of students participated in an oral discussion task. The underlying assumption was that students could be taught to engage with each other and with the task in a way that would foster the creation and exploitation of learning opportunities. Intact classes were randomly assigned to the experimental or control condition, and triads from within each group were videotaped at the beginning and end of the experimental intervention. Data taken from the videotapes were analyzed in order to measure changes in overall participation, strategic participation, and the use of the individual strategies included in the program. The pretest showed that prior to strategy training, interaction patterns frequently did not reflect those interactions deemed important for language acquisition as identified within both traditional second language acquisition (SLA) and sociocultural research. The posttest revealed, however, that the strategy training program was largely successful in encouraging students to engage in these types of interactional sequences. [source]

Individual feeding specialisation in shorebirds: population consequences and conservation implications

BIOLOGICAL REVIEWS, Issue 4 2000
SARAH E. A. LE V. DIT DURELL
ABSTRACT Individual feeding specialisation in shorebirds is reviewed, and the possible mechanisms involved in such specialisations. Any specialisation can be seen as an individual strategy, and the optimum strategy for any given individual will be conditional upon its specific priorities and constraints. Some specialisations are related to social status and some to individual skills. Some are also probably frequency-dependent. However, most shorebird specialisations are constrained to a large extent by individual morphology, particularly bill morphology. For example, larger birds are able to handle larger prey, and birds with longer bills are able to feed on more deeply buried prey. Sex differences in bill length are uncommon in the Charardriidae, which are surface peckers, but are common in the Scolopacidae, which feed by probing in soft substrates. Sex differences in bill morphology are frequently associated with sex differences in feeding specialisation. There is evidence that different feeding specialisations are associated with different payoffs, in which case the probability of failing to reproduce or of dying will not be distributed equally throughout the population. I consider the population consequences of such feeding specialisations, particularly the different risks and benefits associated with different habitats or diets. I also consider the way in which individuals may differ in their response to habitat loss or change. I suggest that population models designed to predict the effect of habitat loss or change on shorebirds should have the ability to investigate the differential response of certain sections of the population, particularly different ages or sexes, that specialise in different diets or feeding methods. [source]