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Heterogeneous Patterns (heterogeneous + pattern)
Selected AbstractsComorbidity and mixed anxiety-depressive disorder: clinical curiosity or pathophysiological need?HUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue S1 2001Hans-Ulrich Wittchen Abstract The paper reviews available epidemiological evidence for the existence of and the implications of comorbidity of anxiety and depressive disorders and mixed anxiety,depressive (MAD) disorders. Using epidemiolological evidence of prevalence and incidence and data relating to time-course of illness, risk factor and outcome, it is concluded: (1) that anxiety,depression comorbidity is quite frequent in epidemiological and clinical settings throughout the world; (2) this comorbidity is diagnosis-specific and is associated with increased vulnerabilities and risks as well as poorer outcome and marked disabilities; and (3) no such evidence was found for MAD disorders. Contrary to what was predicted, the prevalence of MAD disorders was quite low even when using the more recent criteria of the Diagnostic and Statistical Manual of Mental Disorders, 4th edition. (4) Furthermore, there was quite a heterogeneous pattern in terms of risk, severity and outcome making it questionable whether this disorder, as currently defined, is a clinical entity. These findings are discussed in terms of two perspectives, the ,lumpers' with their dimensional view and the ,splitters' with their categorical view. It is concluded that although comorbidity of threshold anxiety and depressive disorders seems to be an important phenomenon, no such evidence is provided for MAD disorders. Copyright © 2001 John Wiley & Sons, Ltd. [source] Xenobiotic activity in serum and sperm chromatin integrity in European and inuit populationsMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 4 2008Tanja Krüger Abstract Lipophilic persistent organic pollutants (POPs) are ubiquitous in the environment and suspected to interfere with hormone activities and reproduction. In previous studies we demonstrated that POP exposure can affect sperm DNA integrity and differences between Inuits and Europeans in sperm DNA integrity and xenobiotic activity were observed. The aim of this study was to investigate possible relations between human sperm chromatin integrity and the xenobiotic serum activity of lipophilic POPs assessed as effects on the estrogen (ER), androgen (AR), and/or aryl hydrocarbon (AhR) receptors. Human sperm chromatin integrity was assessed as DNA fragmentation index (%DFI) and high DNA stainability (%HDS) using the flow cytometric sperm chromatin structure assay (SCSA). Xenobiotic receptor activities were determined using chemically activated luciferase gene expression (CALUX) assay. The study included 53 Greenlandic Inuits and 247 Europeans (Sweden, Warsaw (Poland) and Kharkiv (Ukraine)). A heterogeneous pattern of correlations was found. For Inuits, ER and AhR activities and %DFI were inversely correlated, whereas a positive correlation between AR activity and %DFI was found for Europeans. In contrast, no correlation between receptor activities and %HDS was observed for Inuits but for Europeans positive and negative correlations were observed between ER and AR activities and %HDS, respectively. We suggest that the different patterns of xenobiotic serum activities, in combination with diet associated factors and/or genetics, might be connected to the observed differences in sperm chromatin integrity between the Inuits and Europeans. Mol. Reprod. Dev. 75: 669,680, 2008. © 2007 Wiley-Liss, Inc. [source] Analysis of the autoimmune epitopes on human testicular NASP using recombinant and synthetic peptidesCLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 2 2000I. N. Batova The human nuclear autoantigenic sperm protein, NASP, is a testicular histone-binding protein of 787 amino acids to which most vasectomized men develop autoantibodies. In this study to define the boundaries of antigenic regions and epitope recognition pattern, recombinant deletion mutants spanning the entire protein coding sequence and a human NASP cDNA sublibrary were screened with vasectomy patients' sera. Employing panel sera from 21 vasectomy patients with anti-sperm antibodies, a heterogeneous pattern of autoantibody binding to the recombinant polypeptides was detected in ELISA and immunoblotting. The majority of sera (20/21) had antibodies to one or more of the NASP fusion proteins. Antigenic sites preferentially recognized by the individual patients' sera were located within aa 32,352 and aa 572,787. Using a patient's serum selected for its reactivity to the whole recombinant protein in Western blots, cDNA clones positive for the C-terminal domain of the molecule were identified. The number and location of linear epitopes in this region were determined by synthetic peptide mapping and inhibition studies. The epitope-containing segment was delimited to the sequence aa 619,692 and analysis of a series of 74 concurrent overlapping 9mer synthetic peptides encompassing this region revealed four linear epitopes: amino acid residues IREKIEDAK (aa 648,656), KESQRSGNV (aa 656,664), AELALKATL (aa 665,673) and GFTPGGGGS (aa 680,688). All individual patients' sera reacted with epitopes within the sequence IRE,.GGS (aa 648,688). The strongest reactivity was displayed by peptides corresponding to the sequence AELALKATL (aa 665,673). Thus, multiple continuous autoimmune epitopes in NASP involving sequences in the conserved C-terminal domain as well as in the less conserved testis-specific N-terminal region comprising the histone-binding sites, as predicted for an antigen-driven immune response, may be a target of autoantibodies in vasectomized men and may provide a relevant laboratory variable to describe more accurately the spectrum of autoantibody specificities associated with the clinical manifestation of vasectomy. [source] Regional heterogeneity in the developing palate: morphological and molecular evidence for normal and abnormal palatogenesisCONGENITAL ANOMALIES, Issue 2 2006Junko Okano ABSTRACT Development of the mammalian secondary palate involves the growth, elevation, medial elongation and midline fusion of palatal shelves. Recent morphological and molecular studies on palatogenesis suggest that the developing palate is not a homogeneous organ but each part may behave differently during organogenesis. Especially, some key molecules involved in palate development have been shown to exhibit heterogeneous patterns of expression in the palatal tissue. Therefore it seems necessary to recognize the regional heterogeneity of the developing palate along the dorsoventral and anteroposterior axes when analyzing the mechanisms of normal and abnormal morphogenesis. Based on recent studies, we discuss the issue of the regional heterogeneity in the fetal palate and propose a principle that divides the fetal palate into several regions from the morphological and molecular standpoint. [source] The spatial distribution of badgers, setts and latrines: the risk for intra-specific and badger-livestock disease transmissionECOGRAPHY, Issue 4 2008Monika Böhm The spatial distribution of wildlife hosts and the associated environmental distribution of their excretory products are important factors associated with the risk of disease transmission between wildlife and livestock. At a landscape scale, heterogeneous distribution of a wildlife host will create regional hot spots for disease risk, while at the farm level, distributional patterns of wildlife excretory products as well as habitat use are of primary importance to the assessment of disease risk to livestock. In the UK, badgers have been implicated in the transmission of bovine tuberculosis to cattle. In this study, we focus on the spatial and social organization and habitat use of badgers as well as the distributions of their excretions at latrine and sett sites to assess intra- and inter-species (badger,cattle) disease risk. Across the study site, badger latrines and setts were found in prominent clusters, at distances of up to 250 and 200 m respectively. This was partly due to small-scale clustering of latrines around sett sites, so that disease risk may be higher within the vicinity of setts. The clustered distribution suggests that sites of high risk for TB transmission may be localised within farms. Exclusion of cattle from the few sett and latrine sites within their grazing pasture is therefore likely to provide an effective way of reducing the risk of disease transmission. We also found evidence of social sub-division within badger social groups based on differences in the use of main and outlier setts. This may contribute to localised clusters of infection within the badger population, resulting in heterogeneous patterns of environmental disease risk to the wider host community. A greater understanding of variation in host behaviour and its implications for patterns of disease will allow the development of more targeted and effective management strategies for wildlife disease in group-living hosts. [source] Landscape issues in plant ecologyECOGRAPHY, Issue 2 2002Sylvie De Blois In the last decade, we have seen the emergence and consolidation of a conceptual framework that recognizes the landscape as an ecological unit of interest. Plant ecologists have long emphasized landscape-scale issues, but there has been no recent attempt to define how landscape concepts are now integrated in vegetation studies. To help define common research paradigms in both landscape and plant ecology, we discuss issues related to three main landscape concepts in vegetation researches, reviewing theoretical influences and emphasizing recent developments. We first focus on environmental relationships, documenting how vegetation patterns emerge from the influence of local abiotic conditions. The landscape is the physical environment. Disturbances are then considered, with a particular attention to human-driven processes that often overrule natural dynamics. The landscape is a dynamic space. As environmental and historical processes generate heterogeneous patterns, we finally move on to stress current evidence relating spatial structure and vegetation dynamics. This relates to the concept of a landscape as a patch-corridor-matrix mosaic. Future challenges involve: 1) the capacity to evaluate the relative importance of multiple controlling processes at broad spatial scale; 2) better assessment of the real importance of the spatial configuration of landscape elements for plant species and finally; 3) the integration of natural and cultural processes and the recognition of their interdependence in relation to vegetation management issues in human landscapes. [source] Individual versus social complexity, with particular reference to ant coloniesBIOLOGICAL REVIEWS, Issue 2 2001CARL ANDERSON ABSTRACT Insect societies , colonies of ants, bees, wasps and termites , vary enormously in their social complexity. Social complexity is a broadly used term that encompasses many individual and colony-level traits and characteristics such as colony size, polymorphism and foraging strategy. A number of earlier studies have considered the relationships among various correlates of social complexity in insect societies; in this review, we build upon those studies by proposing additional correlates and show how all correlates can be integrated in a common explanatory framework. The various correlates are divided among four broad categories (sections). Under ,polyphenism' we consider the differences among individuals, in particular focusing upon ,caste' and specialization of individuals. This is followed by a section on ,totipotency' in which we consider the autonomy and subjugation of individuals. Under this heading we consider various aspects such as intracolony conflict, worker reproductive potential and physiological or morphological restrictions which limit individuals' capacities to perform a range of tasks or functions. A section entitled ,organization of work' considers a variety of aspects, e.g. the ability to tackle group, team or partitioned tasks, foraging strategies and colony reliability and efficiency. A final section,,communication and functional integration', considers how individual activity is coordinated to produce an integrated and adaptive colony. Within each section we use illustrative examples drawn from the social insect literature (mostly from ants, for which there is the best data) to illustrate concepts or trends and make a number of predictions concerning how a particular trait is expected to correlate with other aspects of social complexity. Within each section we also expand the scope of the arguments to consider these relationships in a much broader sense of'sociality' by drawing parallels with other ,social' entities such as multicellular individuals, which can be understood as ,societies' of cells. The aim is to draw out any parallels and common causal relationships among the correlates. Two themes run through the study. The first is the role of colony size as an important factor affecting social complexity. The second is the complexity of individual workers in relation to the complexity of the colony. Consequently, this is an ideal opportunity to test a previously proposed hypothesis that ,individuals of highly social ant species are less complex than individuals from simple ant species' in light of numerous social correlates. Our findings support this hypothesis. In summary, we conclude that, in general, complex societies are characterized by large colony size, worker polymorphism, strong behavioural specialization and loss of totipotency in its workers, low individual complexity, decentralized colony control and high system redundancy, low individual competence, a high degree of worker cooperation when tackling tasks, group foraging strategies, high tempo, multi-chambered tailor-made nests, high functional integration, relatively greater use of cues and modulatory signals to coordinate individuals and heterogeneous patterns of worker-worker interaction. Key words: Ants, insect societies, individual complexity, social complexity, polyphenism, totitpotency, work organization, functional integration, sociality. [source] Hydrodynamics and mass transfer coefficient in activated sludge aerated stirred column reactor: experimental analysis and modelingBIOTECHNOLOGY & BIOENGINEERING, Issue 4 2005Bo Jin Abstract The aerated stirred reactor (ASR) has been widely used in biochemical and wastewater treatment processes. The information describing how the activated sludge properties and operation conditions affect the hydrodynamics and mass transfer coefficient is missing in the literature. The aim of this study was to investigate the influence of flow regime, superficial gas velocity (UG), power consumption unit (P/VL), sludge loading, and apparent viscosity (,ap) of activated sludge fluid on the mixing time (tm), gas hold-up (,), and volumetric mass transfer coefficient (kLa) in an activated sludge aerated stirred column reactor (ASCR). The activated sludge fluid performed a non-Newtonian rheological behavior. The sludge loading significantly affected the fluid hydrodynamics and mass transfer. With an increase in the UG and P/VL, the , and kLa increased, and the tm, decreased. The ,, kLa, and tm, were influenced dramatically as the flow regime changed from homogeneous to heterogeneous patterns. The proposed mathematical models predicted the experimental results well under experimental conditions, indicating that the UG, P/VL, and ,ap had significant impact on the tm, ,, and kLa. These models were able to give the tm, ,, and kLa values with an error around ±8%, and always less than ±10%. © 2005 Wiley Periodicals, Inc. [source] | |||||||||||||