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Full Complexity (full + complexity)
Selected AbstractsA landscape theory for food web architectureECOLOGY LETTERS, Issue 8 2008Neil Rooney Abstract Ecologists have long searched for structures and processes that impart stability in nature. In particular, food web ecology has held promise in tackling this issue. Empirical patterns in food webs have consistently shown that the distributions of species and interactions in nature are more likely to be stable than randomly constructed systems with the same number of species and interactions. Food web ecology still faces two fundamental challenges, however. First, the quantity and quality of food web data required to document both the species richness and the interaction strengths among all species within food webs is largely prohibitive. Second, where food webs have been well documented, spatial and temporal variation in food web structure has been ignored. Conversely, research that has addressed spatial and temporal variation in ecosystems has generally ignored the full complexity of food web architecture. Here, we incorporate empirical patterns, largely from macroecology and behavioural ecology, into a spatially implicit food web structure to construct a simple landscape theory of food web architecture. Such an approach both captures important architectural features of food webs and allows for an exploration of food web structure across a range of spatial scales. Finally, we demonstrated that food webs are hierarchically organized along the spatial and temporal niche axes of species and their utilization of food resources in ways that stabilize ecosystems. [source] Environmental epigenomics in human health and diseaseENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 1 2008Dana C. Dolinoy Abstract The epigenome consists of the DNA methylation marks and histone modifications involved in controlling gene expression. It is accurately reproduced during mitosis and can be inherited transgenerationally. The innate plasticity of the epigenome also enables it to be reprogrammed by nutritional, chemical, and physical factors. Imprinted genes and metastable epialleles represent two classes of genes that are particularly susceptible to environmental factors because their regulation is tightly linked to epigenetic mechanisms. To fully understand the etiology of the most devastating diseases that plague humans, the full complexity of the human epigenome will ultimately need to be characterized. Moreover, the elucidation of the interaction of the environment with the epigenome should allow for the development of novel epigenetic-based diagnostic, prevention, and therapeutic strategies for human diseases. Herein, we introduce the emerging field of environmental epigenomics, discuss the importance of imprinted genes and metastable epialleles as epigenetically labile genomic targets, and endorse the genome-wide identification of the full suite of epigenetically labile targets in both the mouse and human genomes. Environ. Mol. Mutagen., 2008. © 2008 Wiley-Liss, Inc. [source] Prognostic significance of secondary cytogenetic alterations in follicular lymphomasGENES, CHROMOSOMES AND CANCER, Issue 12 2008Nathalie A. Johnson Follicular lymphoma (FL) is an indolent lymphoma with a long median survival. Transformation to a more aggressive histology (TLy) is a major cause of mortality. The critical events leading to TLy are unknown. We assessed the prognostic significance of secondary cytogenetic alterations on overall survival (OS) and transformation from 210 diagnostic FL biopsies. We analyzed serial and transformed karyotypes for recurrent alterations that predict transformation. Over 10 years, 31% of cases developed TLy. The only alteration in diagnostic karyotypes that correlated with an inferior OS was an additional X chromosome in males only (P = 0.005) suggesting that other mechanisms including epigenetic factors and over-expression of genes on the X chromosome may play a role in FL pathogenesis. In transformed karyotypes, 8q24 (MYC) translocations were common (14/37) and resulted in a median survival of 3 months posttransformation (P = 0.01). In serially obtained biopsies (28 pts), 43% of the later biopsies lacked the cytogenetic alterations found in the original FL karyotype, suggesting that karyotypic progression of FL is not strictly linear in all cases. Consequently, studying clonal evolution in FL using serial biopsies may not represent the full complexity of genetic alterations leading to transformation. © 2008 Wiley-Liss, Inc. [source] Spectral-element simulations of global seismic wave propagation,II.GEOPHYSICAL JOURNAL INTERNATIONAL, Issue 1 2002Three-dimensional models, oceans, rotation, self-gravitation Summary We simulate global seismic wave propagation based upon a spectral-element method. We include the full complexity of 3-D Earth models, i.e. lateral variations in compressional-wave velocity, shear-wave velocity and density, a 3-D crustal model, ellipticity, as well as topography and bathymetry. We also include the effects of the oceans, rotation and self-gravitation in the context of the Cowling approximation. For the oceans we introduce a formulation based upon an equivalent load in which the oceans do not need to be meshed explicitly. Some of these effects, which are often considered negligible in global seismology, can in fact play a significant role for certain source,receiver configurations. Anisotropy and attenuation, which were introduced and validated in a previous paper, are also incorporated in this study. The complex phenomena that are taken into account are introduced in such a way that we preserve the main advantages of the spectral-element method, which are an exactly diagonal mass matrix and very high computational efficiency on parallel computers. For self-gravitation and the oceans we benchmark spectral-element synthetic seismograms against normal-mode synthetics for the spherically symmetric reference model PREM. The two methods are in excellent agreement for all body- and surface-wave arrivals with periods greater than about 20 s in the case of self-gravitation and 25 s in the case of the oceans. At long periods the effect of gravity on multiorbit surface waves up to R4 is correctly reproduced. We subsequently present results of simulations for two real earthquakes in fully 3-D Earth models for which the fit to the data is significantly improved compared with classical normal-mode calculations based upon PREM. For example, we show that for trans-Pacific paths the Rayleigh wave can arrive more than a minute earlier than in PREM, and that the Love wave is much shorter in duration. [source] Trends in timing of low stream flows in Canada: impact of autocorrelation and long-term persistenceHYDROLOGICAL PROCESSES, Issue 8 2010Eghbal Ehsanzadeh Abstract The annual timing of river flows might indicate changes that are climate related. In this study, trends in timing of low flows for the Reference Hydrometric Basin Network were investigated under three different hypotheses namely: independence, short-term persistence (STP) and long-term persistence (LTP). Both summer and winter time series were characterized with scaling behaviour providing strong evidence of LTP. The Mann,Kendall trend test was modified to account for STP and LTP, and used to detect trends in timing of low flows. It was found that considering STP and LTP resulted in a significant decrease in the number of detected trends. Numerical analysis showed that the timing of summer 7-day low flows exhibited significant trends in 16, 9 and 7% of stations under independence, STP and LTP assumptions, respectively. Timing of summer low flow shifted toward later dates in western Canada, whereas the majority of stations in the east half of the country (except Atlantic Provinces) experienced a shift toward earlier dates. Timing of winter low flow experienced significant trends in 20, 12, and 6% of stations under independence, STP and LTP assumptions, respectively. Shift in timing of winter low flow toward earlier dates was dominant all over the country where it shifted toward earlier dates in up to 3/4 of time series with significant trends. There are local patterns of upward significant/insignificant trends in southeast, southwest and northern Canada. This study shows that timing of low flows in Canada is time dependent; however, addressing the full complexity of memory properties (i.e. short term vs long term) of a natural process is beyond the scope of this study. Copyright © 2009 John Wiley & Sons, Ltd. [source] SOCIAL NETWORKS AND CROSS-CULTURAL INTERACTION: A NEW INTERPRETATION OF THE FEMALE TERRACOTTA FIGURINES OF HELLENISTIC BABYLONOXFORD JOURNAL OF ARCHAEOLOGY, Issue 2 2007STEPHANIE M. LANGIN-HOOPER Summary. In the study of the Hellenistic period in Babylon, cross-cultural interactions between Greeks and native Babylonians have been primarily interpreted using colonialist theories of Hellenisation, domination, and cultural isolation. This paper finds, however, that such theories cannot adequately explain the types of cross-cultural combinations seen in the archaeological record of female Hellenistic Babylonian terracotta figurines. The forms and functions of these terracotta figurines were substantially altered and combined throughout the Hellenistic period, resulting in Greek-Babylonian multicultural figurines as well as figurines that exhibited new features used exclusively in Hellenistic Babylonia. In order to facilitate a greater understanding of the full complexity of these Greek,Babylonian interactions, a new interpretation of cross,cultural interaction in Hellenistic Babylon is developed in this paper. This Social Networks model provides an alternative framework for approaching both how a hybrid material culture of terracotta figurines was developed and how Hellenistic Babylon became a multicultural society. [source] Models of Change Agency: a Fourfold ClassificationBRITISH JOURNAL OF MANAGEMENT, Issue 2 2003Raymond Caldwell Change agents often play significant roles in initiating, managing or implementing change in organizations. Yet these roles are invariably exaggerated or misrepresented by one-dimensional models that ignore the full complexity and scope of change agent roles. Following a review and theoretical clarification of some of the literature and empirical research on change agency, a new fourfold classification of change agents is proposed, covering leadership, management, consultancy, and team models. The four models reaffirm the significance of the multifaceted and complex roles change agents perform in organizational change, while underlining the importance of conceiving change interventions within organizations as processes that need to be coordinated and effectively managed. [source] A Tale of Two Families: The Mutual Construction of ,Anglo' and Mexican Ethnicities Along the US,Mexico BorderBULLETIN OF LATIN AMERICAN RESEARCH, Issue 1 2005Howard Campbell In the American Southwest and along the US,Mexico border, ,Anglos' and Mexicans are often viewed as the quintessential ,others'. This ethnographic study problematises the Anglo-Mexican opposition with ethnographic data from interviews with a Mexican farmworker family and an ,Anglo' farmer family of the EI Paso Lower Valley. I argue that ,Anglo' hegemony is not based exclusively on cultural separation but often involves hybridity (including ,Mexicanisation') and patron-client relations entailing ,benevolent' paternalism. I show how the concept of ,Anglo' is a contested identity constructed through interactions between Mexicans and Euroamericans. Through this study of border crossings in situations of asymmetrical power relations, I advocate a ,complicit' anthropology that presents competing ethnic groups in their full complexity rather than as stereotypes or caricatures of their ,others.' [source] | |||||||||||||