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Adaptive Nature (adaptive + nature)
Selected AbstractsAdaptive nature of crop cytoplasmNEW PHYTOLOGIST, Issue 4 2009Kristin L. Mercer First page of article [source] Coordinating components in middleware systemsCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 13 2003Matthias Radestock Abstract Configuration and coordination are central issues in the design and implementation of middleware systems and are one of the reasons why building such systems is more complex than constructing stand-alone sequential programs. Through configuration, the structure of the system is established,which elements it contains, where they are located and how they are interconnected. Coordination is concerned with the interaction of the various components,when an interaction takes place, which parties are involved, what protocols are followed. Its purpose is to coordinate the behaviour of the various components to meet the overall system specification. The open and adaptive nature of middleware systems makes the task of configuration and coordination particularly challenging. We propose a model that can operate in such an environment and enables the dynamic integration and coordination of components by observing and coercing their behaviour through the interception of the messages exchanged between them. Copyright © 2003 John Wiley & Sons, Ltd. [source] Spatial independent component analysis of functional MRI time-series: To what extent do results depend on the algorithm used?HUMAN BRAIN MAPPING, Issue 3 2002Fabrizio Esposito Abstract Independent component analysis (ICA) has been successfully employed to decompose functional MRI (fMRI) time-series into sets of activation maps and associated time-courses. Several ICA algorithms have been proposed in the neural network literature. Applied to fMRI, these algorithms might lead to different spatial or temporal readouts of brain activation. We compared the two ICA algorithms that have been used so far for spatial ICA (sICA) of fMRI time-series: the Infomax (Bell and Sejnowski [1995]: Neural Comput 7:1004,1034) and the Fixed-Point (Hyvärinen [1999]: Adv Neural Inf Proc Syst 10:273,279) algorithms. We evaluated the Infomax- and Fixed Point-based sICA decompositions of simulated motor, and real motor and visual activation fMRI time-series using an ensemble of measures. Log-likelihood (McKeown et al. [1998]: Hum Brain Mapp 6:160,188) was used as a measure of how significantly the estimated independent sources fit the statistical structure of the data; receiver operating characteristics (ROC) and linear correlation analyses were used to evaluate the algorithms' accuracy of estimating the spatial layout and the temporal dynamics of simulated and real activations; cluster sizing calculations and an estimation of a residual gaussian noise term within the components were used to examine the anatomic structure of ICA components and for the assessment of noise reduction capabilities. Whereas both algorithms produced highly accurate results, the Fixed-Point outperformed the Infomax in terms of spatial and temporal accuracy as long as inferential statistics were employed as benchmarks. Conversely, the Infomax sICA was superior in terms of global estimation of the ICA model and noise reduction capabilities. Because of its adaptive nature, the Infomax approach appears to be better suited to investigate activation phenomena that are not predictable or adequately modelled by inferential techniques. Hum. Brain Mapping 16:146,157, 2002. © 2002 Wiley-Liss, Inc. [source] Why colour in subterranean vertebrates?JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 5 2009Exploring the evolution of colour patterns in caecilian amphibians Abstract The proximate functions of animal skin colour are difficult to assign as they can result from natural selection, sexual selection or neutral evolution under genetic drift. Most often colour patterns are thought to signal visual stimuli; so, their presence in subterranean taxa is perplexing. We evaluate the adaptive nature of colour patterns in nearly a third of all known species of caecilians, an order of amphibians most of which live in tropical soils and leaf litter. We found that certain colour pattern elements in caecilians can be explained based on characteristics concerning above-ground movement. Our study implies that certain caecilian colour patterns have convergently evolved under selection and we hypothesize their function most likely to be a synergy of aposematism and crypsis, related to periods when individuals move overground. In a wider context, our results suggest that very little exposure to daylight is required to evolve and maintain a varied array of colour patterns in animal skin. [source] Regional, ontogenetic, and sex-related variations in elastic properties of cortical bone in baboon mandiblesAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 4 2010Qian Wang Abstract Understanding the mechanical features of cortical bone and their changes with growth and adaptation to function plays an important role in our ability to interpret the morphology and evolution of craniofacial skeletons. We assessed the elastic properties of cortical bone of juvenile and adult baboon mandibles using ultrasonic techniques. Results showed that, overall, cortical bone from baboon mandibles could be modeled as an orthotropic elastic solid. There were significant differences in the directions of maximum stiffness, thickness, density, and elastic stiffness among different functional areas, indicating regional adaptations. After maturity, the cortical bone becomes thicker, denser, and stiffer, but less anisotropic. There were differences in elastic properties of the corpus and ramus between male and female mandibles which are not observed in human mandibles. There were correlations between cortical thicknesses and densities, between bone elastic properties and microstructural configuration, and between the directions of maximum stiffness and bone anatomical axes in some areas. The relationships between bone extrinsic and intrinsic properties bring us insights into the integration of form and function in craniofacial skeletons and suggest that we need to consider both macroscopic form, microstructural variation, and the material properties of bone matrix when studying the functional properties and adaptive nature of the craniofacial skeleton in primates. The differences between baboon and human mandibles is at variance to the pattern of differences in crania, suggesting differences in bone adaption to varying skeletal geometries and loading regimes at both phylogenetic and ontogenetic levels. Am J Phys Anthropol, 2010. © 2009 Wiley-Liss, Inc. [source] Primate sociality in evolutionary contextAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2005Alexandra E. Müller Abstract Much work has been done to further our understanding of the mechanisms that underlie the diversity of primate social organizations, but none has addressed the limits to that diversity or the question of what causes species to either form or not form social networks. The fact that all living primates typically live in social networks makes it highly likely that the last common ancestor of living primates already lived in social networks, and that sociality formed an integral part of the adaptive nature of primate origins. A characterization of primate sociality within the wider mammalian context is therefore essential to further our understanding of the adaptive nature of primate origins. Here we determine correlates of sociality and nonsociality in rodents as a model to infer causes of sociality in primates. We found sociality to be most strongly associated with large-bodied arboreal species that include a significant portion of fruit in their diet. Fruits and other plant products, such as flowers, seeds, and young leaves, are patchily distributed in time and space and are therefore difficult to find. These food resources are, however, predictable and dependable when their location is known. Hence, membership in a social unit can maximize food exploitation if information on feeding sites is shared. Whether sociality evolved in the primate stem lineage or whether it was already present earlier in the evolution of Euarchontoglires remains uncertain, although tentative evidence points to the former scenario. In either case, frugivory is likely to have played an important role in maintaining the presence of a social lifestyle throughout primate evolution. Am J Phys Anthropol, 2005. © 2005 Wiley-Liss, Inc. [source] Women in special hospitals: understanding the presenting behaviour of women diagnosed with borderline personality disorderJOURNAL OF PSYCHIATRIC & MENTAL HEALTH NURSING, Issue 4 2001T. M. Wilkins RMNH Ad.Dip MA This paper critically examines the development of the concept of borderline personality disorder (BPD) in terms of the assumed centrality of abnormal early environments and abusive relationships. It is suggested that if BPD is conceptualized as an expression of past experiences in adult life, information regarding early histories can assist in ,making sense' of later behaviour. The aim of this review therefore is to explore how histories of women diagnosed as BPD, within a High Secure Psychiatric Hospital, may facilitate an interpretation of the ,adaptive' nature of presenting ,symptomology'. Case note material is utilized to gain insight into specific aspects of childhood experiences that have been documented, and are thus deemed significant. These findings support the perception that the role of the early environment and associated relationships are significant within written accounts of women diagnosed as having BPD. By exploring the links between trauma and BPD, this article suggests that an understanding of the effects of trauma and the importance of relationships can offer a way forward for self-reflection and future care. [source] | ||||||||||