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Complex Interactions (complex + interaction)
Selected AbstractsFactors influencing oral colonization of mutans streptococci in young childrenAUSTRALIAN DENTAL JOURNAL, Issue 2 2007V. Law Abstract This paper aims to critically review current knowledge about the key factors involved in oral colonization of the cariogenic group of bacteria, mutans streptococci (MS) in young children. MS, consisting mainly of the species Streptococcus mutans and Streptococcus sobrinus, are commonly cultured from the mouths of infants, with prevalence of infection ranging from around 30 per cent in 3 month old predentate children to over 80 per cent in 24 month old children with primary teeth. MS is usually transmitted to children through their mothers, and the risk of transmission increases with high maternal salivary levels of MS and frequent inoculation. Factors that affect the colonization of MS may be divided into bacterial virulence, host-related and environmental factors. Complex interaction among these factors determine the success and timing of MS colonization in the child. As clinical studies have shown that caries risk is correlated with age at which initial MS colonization occurred, strategies for the prevention of dental caries should include timely control of colonization of the cariogenic bacteria in the mouths of young children. [source] Do competitive intraguild interactions affect space and habitat use by small carnivores in a forested landscape?ECOGRAPHY, Issue 4 2006Caroline St-Pierre Complex interactions such as interference competition and predation, including intraguild predation, are now recognized as important components in animal community structure. At the lower end of a guild, weasels may be highly affected by other guild members due to small body size in relation to other predators. In 2000 and 2001, we radio-collared 24 ermines Mustela erminea and 25 long-tailed weasels M. frenata in 2 areas that differed in abundance of guild members. We tested the hypothesis that when faced with an increased density of other guild members, weasels would modify space and habitat use to reduce the risk of predation associated with encounters involving guild members. We predicted that weasels would increase use of specific habitats (such as refuges) to reduce encounter rates in the presence of a greater number of guild members. Because M. erminea is smaller than M. frenata and thus better able to take advantage of small rodent burrows as refuges from predators and as feeding grounds, we also predicted that M. frenata would show a stronger response to a higher abundance of guild members than M. erminea. Results were consistent with our predictions. Faced with an increased abundance of guild members, M. frenata showed increased habitat selectivity and reduced activity levels, which resulted in increased daily travel distances and increased home ranges. Mustela erminea responded to an increased abundance of guild members through reduced use of preferred habitat which M. frenata already occupied. The contrasting pattern of habitat selection observed between the 2 mustelid species suggested cascading effects, whereby large-predator pressure on M. frenata relaxed pressure of M. frenata on M. erminea. Our results draw attention to the likelihood that competitive intraguild interactions play a facilitating role in M. erminea,M. frenata coexistence. [source] A phenomenological study of spirituality and learning processes at work: Exploring the holistic theory of knowledge and learningHUMAN RESOURCE DEVELOPMENT QUARTERLY, Issue 4 2007Suzanne J. Gallagher The holistic theory of knowledge and learning offers an integrative framework for understanding the interactions of cognitions, feelings, and behavior in learning. Explicit (cognitions), implicit ( behavior), and emancipatory (feelings, values, spirituality) knowledge facets interact in learning processes. Little is known, however, about the nature of these interactions and the role of spirituality in learning. A phenomenological study of professionals' learning processes at work showed that knowledge facets interact in learning through expressing, informing, changing, and guiding one another. Complex interactions within knowledge facets were identified as well as the dangers of learning using only one knowledge facet. The essential role of community in learning processes was affirmed, and the guiding, informing role of spirituality in learning at work was revealed. [source] Combined Coinhibitory and Costimulatory Modulation with Anti-BTLA and CTLA4Ig Facilitates Tolerance in Murine Islet AllograftsAMERICAN JOURNAL OF TRANSPLANTATION, Issue 12 2007W. Truong Complex interactions between positive and negative cosignaling receptors ultimately determine the fate of the immune response. The recently identified coinhibitory receptor, B and T lymphocyte attenuator (BTLA), contributes to regulation of autoimmune and potentially alloimmune responses. We investigated the role of BTLA in a fully major histocompatibility complex-mismatched mouse islet transplant model. We report that anti-BTLA mAb (6F7) alone does not accelerate graft rejection. Rather, while CTLA4Ig alone improved allograft survival, the addition of anti-BTLA mAb to CTLA4Ig led to indefinite (>100 days) allograft survival. Immediately after treatment with anti-BTLA mAb and CTLA4Ig, islet allografts showed intact islets and insulin production despite a host cellular response, with local accumulation of Foxp3+ cells. We clearly demonstrate that combined therapy with anti-BTLA mAb and CTLA4Ig mice induced donor-specific tolerance, since mice accepted a second donor-specific islet graft without further treatment and rejected third party grafts. CTLA4Ig and anti-BTLA mAb limited the initial in vivo proliferation of CFSE-labeled allogeneic lymphocytes, and anti-BTLA mAb enhanced the proportion of PD-1 expressing T cells while depleting pathogenic BTLA+ lymphocytes. We conclude that targeting the BTLA pathway in conjunction with CTLA4Ig costimulatory blockade may be a useful strategy for promoting immunological tolerance in murine islet allografts. [source] Complex interactions among mammalian carnivores in Australia, and their implications for wildlife managementBIOLOGICAL REVIEWS, Issue 3 2005Alistair S. Glen ABSTRACT Mammalian carnivore populations are often intensively managed, either because the carnivore in question is endangered, or because it is viewed as a pest and is subjected to control measures, or both. Most management programmes treat carnivore species in isolation. However, there is a large and emerging body of evidence to demonstrate that populations of different carnivores interact with each other in a variety of complex ways. Thus, the removal or introduction of predators to or from a system can often affect other species in ways that are difficult to predict. Wildlife managers must consider such interactions when planning predator control programmes. Integrated predator control will require a greater understanding of the complex relationships between species. In many parts of the world, sympatric species of carnivores have coexisted over an evolutionary time scale so that niche differentiation has occurred, and competition is difficult to observe. Australia has experienced numerous introductions during the past 200 years, including those of the red fox (Vulpes vulpes) and the feral cat (Felis catus). These species now exist in sympatry with native mammalian predators, providing ecologists with the opportunity to study their interactions without the confounding effects of coevolution. Despite an increasing body of observational evidence for complex interactions among native and introduced predators in Australia, few studies have attempted to clarify these relationships experimentally, and the interactions remain largely unacknowledged. A greater understanding of these interactions would provide ecologists and wildlife managers world-wide with the ability to construct robust predictive models of carnivore communities, and to identify their broader effects on ecosystem functioning. We suggest that future research should focus on controlled and replicated predator removal or addition experiments. The dingo (Canis lupus dingo), as a likely keystone species, should be a particular focus of attention. [source] SecondSkin: An interactive method for appearance transferCOMPUTER GRAPHICS FORUM, Issue 7 2009A. Van Den Hengely Abstract SecondSkin estimates an appearance model for an object visible in a video sequence, without the need for complex interaction or any calibration apparatus. This model can then be transferred to other objects, allowing a non-expert user to insert a synthetic object into a real video sequence so that its appearance matches that of an existing object, and changes appropriately throughout the sequence. As the method does not require any prior knowledge about the scene, the lighting conditions, or the camera, it is applicable to video which was not captured with this purpose in mind. However, this lack of prior knowledge precludes the recovery of separate lighting and surface reflectance information. The SecondSkin appearance model therefore combines these factors. The appearance model does require a dominant light-source direction, which we estimate via a novel process involving a small amount of user interaction. The resulting model estimate provides exactly the information required to transfer the appearance of the original object to new geometry composited into the same video sequence. [source] Homicide, psychopathology, prosecutorial and jury discretion and the death penaltyCRIMINAL BEHAVIOUR AND MENTAL HEALTH, Issue 4 2000Chief, Division of Forensic Psychiatry, Richard M. Yarvis MD MPH Professor of Clinical Psychiatry Introduction The American preoccupation with the death penalty persists and, in fact, shows no sign of abatement. This is demonstrated not only by attitudinal measures but also by the quickening pace of executions. In California, homicide convictions can result in either 25-year-to-life, life-with-no-possibility-of-parole, or death sentences. The ultimate outcome in any given case is determined by a complex interaction of prosecutorial and jury decisions. Three vignettes illustrate how heinous crimes have been handled quite variably. Method A data set comprising 115 homicide cases was examined. To determine how murderers who qualify for the death penalty differed, if at all, from those who did not so qualify, 52 defendants who met the criteria for a death sentence were compared with 63 who did not. Criteria utilized and ignored by prosecutors in seeking the death penalty were analysed by comparing 39 cases in which death sentences could have been and were sought with 13 cases in which prosecutors chose to seek a lesser penalty instead. Finally, criteria utilized and ignored by juries to reach sentencing decisions were analysed by comparing 25 cases in which juries chose not to hand down death sentences with 14 cases in which they did render death verdicts. Results Special circumstance murderers did not differ significantly on personal variables from ordinary murderers. (1) Special circumstances were invariably charged when more than one criterion for this was present. Robbery and sexual assault usually provoked a special circumstances charge. Mitigating factors did not deter prosecutors from charging a special circumstance. (2) There was no excess of aggravating factors in individuals sentenced to death by juries, indeed there was a trend for the opposite to be the case, but there was a trend for mitigating factors to be commoner in those excused the death penalty. Conclusion It is not clear that the death penalty process in California carries out the legislature's intent but the US Supreme Court's 1976 mandate that mitigating and aggravating factors should provide discretion may be having a modest impact. Copyright © 2000 Whurr Publishers Ltd. [source] Obesity, serious mental illness and antipsychotic drugsDIABETES OBESITY & METABOLISM, Issue 7 2009Richard I. G. Holt The prevalence of overweight and obesity is higher in people with mental illness than in the general population. Body weight is tightly regulated by a complex system involving the cortex and limbic system, the hypothalamus and the gastrointestinal tract. While there are justifiable concerns about the weight gain associated with antipsychotic medication, it is too simplistic to ascribe all obesity in people with serious mental illness (SMI) to their drug treatment. The development of obesity in SMI results from the complex interaction of the genotype and environment of the person with mental illness, the mental illness itself and antipsychotic medication. There are dysfunctional reward mechanisms in SMI that may contribute to poor food choices and overeating. While it is clear that antipsychotics have profound effects to stimulate appetite, no one receptor interaction provides an adequate explanation for this effect, and many mechanisms are likely to be involved. The complexity of the system regulating body weight allows us to start to understand why some individuals appear much more prone to weight gain and obesity than others. [source] Numerical simulation of the inception of channel meanderingEARTH SURFACE PROCESSES AND LANDFORMS, Issue 9 2005Jennifer G. Duan Abstract The inception of channel meandering is the result of the complex interaction between flow, bed sediment, and bank material. A depth-averaged two-dimensional hydrodynamic model is developed to simulate the inception and development of channel meandering processes. The sediment transport model calculates both bedload and suspended load assuming equilibrium sediment transport. Bank erosion consists of two interactive processes: basal erosion and bank failure. Basal erosion is calculated from a newly derived equation for the entrainment of sediment particles by hydrodynamic forces. The mass conservation equation, where basal erosion and bank failure are considered source terms, was solved to obtain the rate of bank erosion. The parallel bank failure model was tested with the laboratory experiments of Friedkin on the initiation and evolution processes of non-cohesive meandering channels. The model replicates the downstream translation and lateral extension of meandering loops reasonably well. Plots of meandering planforms illustrate the evolution of sand bars and redistribution of flow momentum in meandering channels. This numerical modelling study demonstrates the potential of depth-integrated two-dimensional models for the simulation of meandering processes. Copyright © 2005 John Wiley & Sons, Ltd. [source] What neurobiology cannot tell us about addictionADDICTION, Issue 5 2010Harold Kalant ABSTRACT Molecular neurobiological studies have yielded enormous amounts of valuable information about neuronal response mechanisms and their adaptive changes. However, in relation to addiction this information is of limited value because almost every cell function appears to be involved. Thus it tells us only that neurons adapt to ,addictive drugs' as they do to all sorts of other functional disturbances. This information may be of limited help in the development of potential auxiliary agents for treatment of addiction. However, a reductionist approach which attempts to analyse addiction at ever finer levels of structure and function, is inherently incapable of explaining what causes these mechanisms to be brought into play in some cases and not in others, or by self-administration of a drug but not by passive exposure. There is abundant evidence that psychological, social, economic and specific situational factors play important roles in initiating addiction, in addition to genetic and other biological factors. Therefore, if we hope to be able to make predictions at any but a statistical level, or to develop effective means of prevention, it is necessary to devise appropriate integrative approaches to the study of addiction, rather than pursue an ever-finer reductive approach which leads steadily farther away from the complex interaction of drug, user, environment and specific situations that characterizes the problem in humans. [source] Genetic aspects of pathological gambling: a complex disorder with shared genetic vulnerabilitiesADDICTION, Issue 9 2009Daniela S. S. Lobo ABSTRACT Aims To summarize and discuss findings from genetic studies conducted on pathological gambling (PG). Methods Searches were conducted on PubMed and PsychInfo databases using the keywords: ,gambling and genes', ,gambling and family' and ,gambling and genetics', yielding 18 original research articles investigating the genetics of PG. Results Twin studies using the Vietnam Era Twin Registry have found that: (i) the heritability of PG is estimated to be 50,60%; (ii) PG and subclinical PG are a continuum of the same disorder; (iii) PG shares genetic vulnerability factors with antisocial behaviours, alcohol dependence and major depressive disorder; (iv) genetic factors underlie the association between exposure to traumatic life-events and PG. Molecular genetic investigations on PG are at an early stage and published studies have reported associations with genes involved in the brain's reward and impulse control systems. Conclusions Despite the paucity of studies in this area, published studies have provided considerable evidence of the influence of genetic factors on PG and its complex interaction with other psychiatric disorders and environmental factors. The next step would be to investigate the association and interaction of these variables in larger molecular genetic studies with subphenotypes that underlie PG. Results from family and genetic investigations corroborate further the importance of understanding the biological underpinnings of PG in the development of more specific treatment and prevention strategies. [source] A region on equine chromosome 13 is linked to recurrent airway obstruction in horsesEQUINE VETERINARY JOURNAL, Issue 3 2007U. JOST Summary Reasons for study: Equine recurrent airway obstruction (RAO) is probably dependent on a complex interaction of genetic and environmental factors and shares many characteristic features with human asthma. Interleukin 4 receptor , chain (IL4RA) is a candidate gene because of its role in the development of human asthma, confirmation of this association is therefore required. Methods: The equine BAC clone containing the IL4RA gene was localised to ECA13q13 by the FISH method. Microsatellite markers in this region were investigated for possible association and linkage with RAO in 2 large Warmblood halfsib families. Based on a history of clinical signs (coughing, nasal discharge, abnormal breathing and poor performance), horses were classified in a horse owner assessed respiratory signs index (HOARSI 1,4: from healthy, mild, moderate to severe signs). Four microsatellite markers (AHT133, LEX041, VHL47, ASB037) were analysed in the offspring of Sire 1 (48 unaffected HOARSI 1 vs. 59 affected HOARSI 2,4) and Sire 2 (35 HOARSI 1 vs. 50 HOARSI 2,4), age ,7 years. Results: For both sires haplotypes could be established in the order AHT133-LEX047-VHL47-ASB37. The distances in this order were estimated to be 2.9, 0.9 and 2.3 centiMorgans, respectively. Haplotype association with mild to severe clinical signs of chronic lower airway disease (HOARSI 2,4) was significant in the offspring of Sire 1 (P = 0.026) but not significant for the offspring of Sire 2 (P = 0.32). Linkage analysis showed the ECA13q13 region containing IL4RA to be linked to equine chronic lower airway disease in one family (P<0.01), but not in the second family. Conclusions: This supports a genetic background for equine RAO and indicates that IL4RA is a candidate gene with possible locus heterogeneity for this disease. Potential relevance: Identification of major genes for RAO may provide a basis for breeding and individual prevention for this important disease. [source] Frailty predicts long-term mortality in elderly subjects with chronic heart failureEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 12 2005F. Cacciatore Abstract Background, The elderly are characterized by a high prevalence of chronic heart failure (CHF) and frailty, which is a complex interaction of physical, psychological and social impairment. This study aimed to examine the predictive role of frailty on long-term mortality in elderly subjects with CHF. Materials and methods, The study assessed long-term mortality after 12-year follow up in 120 subjects with CHF and 1139 subjects without CHF, selected in 1992, from a random sample of the elderly population in the Campania region of Italy. Frailty was assessed according to a ,Frailty Staging System'. Results, Subjects with CHF were prevalently female (60%) and older than 75 years (mean 75·9 ± 6·7); subjects without CHF were prevalently female (56·4%) and younger than 75 years (mean 74·0 ± 6·3). In subjects with and without CHF stratified into classes of frailty there was a statistically significant increase in age, comorbidity, disability and low social support, and a decrease in MMSE score. Moreover, death progressively increased more with frailty in subjects (70·0% to 94·4%, P < 0·03) than in those without (43·8.% to 88·3%, P < 0·0001) CHF. The Kaplan,Meier analysis shows that at 9 years the probability of survival progressively decreased as frailty increased (45·5% to 0%) in subjects with CHF and from 62·8% to 25·9% in subjects without CHF. The Cox regression analysis indicated that frailty is predictive of mortality in the multivariate model adjusted for several variables including sex and age in subjects with and without CHF. Moreover, the analysis showed that frailty is more predictive of mortality in elderly subjects with CHF when it was analyzed either as continuous (1·48 vs. 1·36) or as a dummy (3 vs. 1 = 1·62 vs. 1·24) variable. Conclusions, Thus mortality among elderly subjects with or without CHF increases with frailty. Moreover, frailty is more predictive of long-term mortality in elderly subjects with than in those without CHF. Hence, frailty represents a new independent variable for predicting long-term mortality in elderly subjects with CHF. [source] National Qualification Frameworks: from policy borrowing to policy learningEUROPEAN JOURNAL OF EDUCATION, Issue 2 2010BORHENE CHAKROUN This article takes up the issue of the internationalisation of Vocational Education and Training (VET) reforms, expressed in the way policy instruments such as National Qualifications Frameworks (NQF) are introduced in the European Training Foundation's (ETF) partner countries. There is an international debate and different perspectives regarding NQFs. These perspectives have largely talked past each other. The article brings together these perspectives and highlights the issues at stake in this field. Through the analysis of ETF interventions in different regions, the article makes a case for new approaches of intervention, namely policy learning, that aim at enabling national stakeholders and that are conducive for home-grown VET policies. The discussion is broad in scope, not only because the article reviews developments in qualifications frameworks across-regions, but also because it highlights the complex interaction of the global and local development when introducing NQFs and the impact of such reforms on VET systems. [source] Novel therapeutic targets in multiple myelomaEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 6 2000Faith E. Davies The aim of this review is to focus on a number of key areas where recent advances in the biology of the disease have not only yielded an understanding of the disease pathogenesis but have also suggested novel treatment approaches. Factors mediating myeloma cell growth, survival and the complex interaction of myeloma cells with the bone marrowmicroenvironment have provided a framework for the rational design of therapeutic agents. The development of such biologically based treatments which target both the tumour cell and the microenvironment, in order to achieve more complete and selective eradication of myeloma cells and the maintenance of minimal residual disease states, may ultimately lead to improved disease-free survivial and potentially a cure. [source] Multiple sclerosis complexity in selected populations: the challenge of Sardinia, insular Italy1EUROPEAN JOURNAL OF NEUROLOGY, Issue 4 2002S. Sotgiu Several lines of evidence indicate a genetic contribution to multiple sclerosis (MS) both in terms of predisposition to the disease and of immunological mechanisms which are known to play crucial roles in MS pathogenesis. The presence of high- and low-risk areas for MS in neighbouring regions supports the theory that MS predisposition is influenced by a complex interaction of genetic and environmental factors. Therefore, the use of genetically homogeneous and geographically isolated populations becomes an increasing requirement to reduce biasing biological variables. Sardinians fulfil these conditions well because of their different phylogeny from Europeans and the unique selective pressures which shaped their genome. Sardinians display amongst the highest MS prevalence rates world-wide and increasing MS incidence rates over time. Also, MS in Sardinia is linked to distinct human leucocyte antigen (HLA) alleles and associated to different patterns of cytokine production from lymphoid cells of different HLA subtypes. In this context, recent findings and future perspectives on the peculiarities of Sardinian MS concerning genetic, immunological and epidemiological aspects are presented. So far, our results indicate that variations at the level of territorial distribution and HLA-association are present which render MS heterogeneous even in this ethnically homogeneous population. [source] The dynamics of developmental system drift in the gene network underlying wing polyphenism in ants: a mathematical modelEVOLUTION AND DEVELOPMENT, Issue 3 2008Marcos Nahmad SUMMARY Understanding the complex interaction between genotype and phenotype is a major challenge of Evolutionary Developmental Biology. One important facet of this complex interaction has been called "Developmental System Drift" (DSD). DSD occurs when a similar phenotype, which is homologous across a group of related species, is produced by different genes or gene expression patterns in each of these related species. We constructed a mathematical model to explore the developmental and evolutionary dynamics of DSD in the gene network underlying wing polyphenism in ants. Wing polyphenism in ants is the ability of an embryo to develop into a winged queen or a wingless worker in response to an environmental cue. Although wing polyphenism is homologous across all ants, the gene network that underlies wing polyphenism has evolved. In winged ant castes, our simulations reproduced the conserved gene expression patterns observed in the network that controls wing development in holometabolous insects. In wingless ant castes, we simulated the suppression of wings by interrupting (up- or downregulating) the expression of genes in the network. Our simulations uncovered the existence of four groups of genes that have similar effects on target gene expression and growth. Although each group is comprised of genes occupying different positions in the network, their interruption produces vestigial discs that are similar in size and shape. The implications of our results for understanding the origin, evolution, and dissociation of the gene network underlying wing polyphenism in ants are discussed. [source] Breathing rhythms and emotionsEXPERIMENTAL PHYSIOLOGY, Issue 9 2008Ikuo Homma Respiration is primarily regulated for metabolic and homeostatic purposes in the brainstem. However, breathing can also change in response to changes in emotions, such as sadness, happiness, anxiety or fear. Final respiratory output is influenced by a complex interaction between the brainstem and higher centres, including the limbic system and cortical structures. Respiration is important in maintaining physiological homeostasis and co-exists with emotions. In this review, we focus on the relationship between respiration and emotions by discussing previous animal and human studies, including studies of olfactory function in relation to respiration and the piriform,amygdala in relation to respiration. In particular, we discuss oscillations of piriform,amygdala complex activity and respiratory rhythm. [source] Analysis of Usp DNA binding domain targeting reveals critical determinants of the ecdysone receptor complex interaction with the response elementFEBS JOURNAL, Issue 13 2001Iwona Grad The steroid hormone, 20-hydroxyecdysone (20E), directs Drosophila metamorphosis via a heterodimeric receptor formed by two members of the nuclear hormone receptors superfamily, the product of the EcR (EcR) and of the ultraspiracle (Usp) genes. Our previous study [Niedziela-Majka, A., Kochman, M., O,yhar, A. (2000) Eur. J. Biochem.267, 507,519] on EcR and Usp DNA-binding domains (EcRDBD and UspDBD, respectively) suggested that UspDBD may act as a specific anchor that preferentially binds the 5, half-site of the pseudo-palindromic response element from the hsp27 gene promoter and thus locates the heterocomplex in the defined orientation. Here, we analyzed in detail the determinants of the UspDBD interaction with the hsp27 element. The roles of individual amino acids in the putative DNA recognition , helix and the roles of the base pairs of the UspDBD target sequence have been probed by site-directed mutagenesis. The results show how the hsp27 element specifies UspDBD binding and thus the polar assembly of the UspDBD/EcRDBD heterocomplex. It is suggested how possible nucleotide deviations within the 5, half-site of the element may be used for the fine-tuning of the 20E-response element specificity and consequently the physiological response. [source] THEORIZING GLOBAL BUSINESS SPACESGEOGRAFISKA ANNALER SERIES B: HUMAN GEOGRAPHY, Issue 3 2009Andrew Jones ABSTRACT. Over the last decade, geographers have paid a great deal of attention to transnational firms (TNCs) and global production networks (GPNs) in the global economy, to the emergence of a mobile transnational business class and also to the development of global or globalizing cities. All three literatures have made important contributions to understanding the spatiality of global economic activity, but each adopts a fairly discreet theoretical and empirical focus. This article aims to outline a number of theoretical dimensions for thinking about how these key strands to the globalization debate can be brought together through the concept of global business spaces. It will propose a framework for understanding the spatialities of global economic activity that seeks to capture the complex interaction of material, social, organizational and virtual spaces that form the context through which it is constituted. With reference to business travel as a key form of economic practice which plays a central role in (re)producing these spaces, it assesses how these emerging spaces of global economic activity present problems for the conceptual categories commonly used by both urban and economic geographers. In so doing, it proposes a series of ways in which a different research agenda can produce new insight into the complex forms of social practice at the centre of global economic activity. [source] Non-double-couple mechanisms in the seismicity preceding the 1991,1993 Etna volcano eruptionGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 2 2001A. Saraņ Summary The temporal evolution of the complete source moment tensor is investigated for 28 earthquakes that occurred at Mt Etna in the period August 1990,December 1991 preceding the biggest eruption of the last three centuries. We perform several tests to check the robustness of the results of inversion considering different frequency ranges and different groups of stations. As well as the selection of good-quality data, the error analysis, statistically significant at the 95 per cent confidence level, is employed to validate the findings of the inversion and to distinguish between physical solutions and artefacts of modelling. For events between 0.3 and 10 km depth, strike-slip mechanisms prevail on normal, inverse and dip-slip mechanisms; this is possibly due to the dyke-induced stress dominating the overall stress field at the surface, producing a continuous switch of the tensile and compressive axes. The regional E,W tension prevails at depth, as indicated by the prevalence of normal mechanisms. An increment of the non-double-couple components is observed immediately before the eruption and can be related to movements of fluids, even though, for some events, the complex interaction between tectonic stress and volcanic activity cannot be excluded. The source time functions retrieved are in general simple and short but some show complexities, as one would expect in volcanic seismicity. From the seismic scalar moment found, we extrapolate an empirical moment,magnitude relation that we compare with other relations proposed for the same area and computed for the duration magnitude and the equivalent Wood,Anderson magnitude. [source] Nitric Oxide-Induced Changes in Endothelial Expression of Phosphodiesterases 2, 3, and 5HEADACHE, Issue 3 2010Christoph J. Schankin MD (Headache 2010;50:431-441) Objective., To investigate nitric oxide (NO)-mediated changes in expression of cyclic nucleotide degrading phosphodiesterases 2A (PDE2A), PDE3B, and PDE5A in human endothelial cells. Background., Nitric oxide induces production of cyclic guanosine monophosphate (cGMP), which along with cyclic adenosine monophosphate (cAMP) is degraded by PDEs. NO donors and selective inhibitors of PDE3 and PDE5 induce migraine-like headache and play a role in endothelial dysfunction during stroke. The current study investigates possible NO modulation of cGMP-related PDEs relevant to headache induction in a cell line containing such PDEs. Methods., Real time polymerase chain reaction and Western blots were used to show expression of PDE2A, PDE3B, and PDE5A in a stable cell line of human brain microvascular endothelial cells. Effects of NO on PDE expression were analyzed at specific time intervals after continued DETA NONOate administration. Results., This study shows the expression of PDE2A, PDE3B, and PDE5A mRNA and PDE3B and PDE5A protein in human cerebral endothelial cells. Long-term DETA NONOate administration induced an immediate mRNA up-regulation of PDE5A (1.9-fold, 0.5 hour), an early peak of PDE2A (1.4-fold, 1 and 2 hours) and later up-regulation of both PDE3B (1.6-fold, 4 hours) and PDE2A (1.7-fold, 8 hours and 1.2-fold after 24 hours). Such changes were, however, not translated into significant changes in protein expression indicating few, if any, functional effects. Conclusions., Long-term NO stimulation modulated PDE3 and PDE5 mRNA expression in endothelial cells. However, PDE3 and PDE5 protein levels were unaffected by NO. The presence of PDE3 or PDE5 in endothelial cells indicates that selective inhibitors may have functional effects in such cells. A complex interaction of cGMP and cAMP in response to NO administration may take place if the mRNA translates into active protein. Whether or not this plays a role in the headache mechanisms remains to be investigated. [source] Pathogenesis of Helicobacter pylori InfectionHELICOBACTER, Issue 2007Shin Maeda Abstract The clinical outcome of Helicobacter pylori infection is determined by a complex interaction between the bacterium and the host. The main bacterial factors associated with pathogenicity comprise outer membrane proteins, including BabA, SabA, OipA, AlpA, and AlpB, the vacuolating cytotoxin VacA and the products of cagPAI. The multitude of putative virulence factors makes it extremely difficult to test the contribution of each individual factor. Much effort has been put into identifying the mechanism associated with H. pylori -associated carcinogenesis. Interaction between bacterial factors such as CagA and host signal transduction pathways seems to be critical for mediating cell transformation, cell proliferation, invasion, apoptosis/anti-apoptosis, and angiogenesis. An animal model using the Mongolian gerbil is a useful model for showing gastric pathology due to H. pylori infection which is similar to that in humans and can be used to evaluate virulence factors including CagA, host responses, and environmental factors such as salt intake. [source] The kidney disease wasting: Inflammation, oxidative stress, and diet-gene interactionHEMODIALYSIS INTERNATIONAL, Issue 4 2006Kamyar KALANTAR-ZADEH Abstract The 350,000 maintenance hemodialysis (MHD) patients in the United States have an unacceptably high mortality rate of >20%/year. Almost half of all deaths are assumed to be cardiovascular. Markers of kidney disease wasting (KDW) such as hypoalbuminemia, anorexia, body weight and fat loss, rather than traditional cardiovascular risk factors, appear to be the strongest predictors of early death in these patients. The KDW is closely related to oxidative stress (SOX). Such SOX markers as serum myeloperoxidase are associated with pro-inflammatory cytokines and poor survival in MHD patients. Identifying the conditions that modulate the KDW/SOX-axis may be the key to improving outcomes in MHD patients. Dysfunctional lipoproteins such as a higher ratio of the high-density lipoprotein inflammatory index (HII) may engender or aggravate the KDW, whereas functionally intact or larger lipoprotein pools, as in hypercholesterolemia and obesity, may mitigate the KDW in MHD patients. Hence, a reverse epidemiology or "bad-gone-good" phenomenon may be observed. Diet and gene and their complex interaction may lead to higher proportions of pro-inflammatory or oxidative lipoproteins such as HII, resulting in the aggravation of the SOX and inflammatory processes, endothelial dysfunction, and subsequent atherosclerotic cardiovascular disease and death in MHD patients. Understanding the factors that modulate the KDW/SOX complex and their associations with genetic polymorphism, nutrition, and outcomes in MHD patients may lead to developing more effective strategies to improve outcomes in this and the 20 to 30 million Americans with chronic disease states such as individuals with chronic heart failure, advanced age, malignancies, AIDS, or cachexia. [source] Factors affecting outcome in liver resectionHPB, Issue 3 2005CEDRIC S. F. LORENZO Abstract Background. Studies demonstrate an inverse relationship between institution/surgeon procedural volumes and patient outcomes. Similar studies exist for liver resections, which recommend referral of patients for liver resections to ,high-volume' centers. These studies did not elucidate the factors that underlie such outcomes. We believe there exists a complex interaction of patient-related and perioperative factors that determine patient outcomes after liver resection. We sought to delineate these factors. Methods. Retrospective review of 114 liver resections by a single surgeon from 1993,2003: Records were reviewed for demographics; diagnosis; type/year of surgery; American Society of Anesthesiologists (ASA) score; preoperative albumin, creatinine, and bilirubin; operative time; intraoperative blood transfusions; epidural use; and intraoperative hypotension. Main outcome measurements were postoperative morbidities, mortalities and length of stay (LOS). Data were analyzed using a multivariate linear regression model (SPSS v10.1 statistical analysis program). Results. Primary indications for resections were hepatocellular carcinoma (HCC) (N=57), metastatic colorectal cancer (N=25), and benign disease (N=18). There were no intraoperative mortalities and 4 perioperative (30-day) mortalities (3.5%). Mortality occurred in patients with malignancies who were older than 50 years. Morbidity was higher in malignant (15.6%) versus benign (5.5%) disease. Complications included bile leak/stricture (N=6), liver insufficiency (N=3), postoperative bleeding (N=2), myocardial infarction (N=2), aspiration pneumonia (N=1), renal insufficiency (N=1), and cancer implantation into the wound (N=1). Average LOS for all resections was 8.6 days. Longer operative time (p=0.04), lower albumin (p<0.001), higher ASA score (p<0.001), no epidural use (p=0.04), and higher creatinine (p<0.001) all correlated positively with longer LOS. ASA score and creatinine were the strongest predictors of LOS. LOS was not affected by patient age, sex, diagnosis, presence of malignancy, intraoperative transfusion requirements, intraoperative hypotension, preoperative bilirubin, case volume per year or year of surgery. Conclusions. Liver resections can be performed with low mortality/morbidity and with acceptable LOS by an experienced liver surgeon. Outcome as measured by LOS is most influenced by patient comorbidities entering into surgery. Annual case volume did not influence LOS and had no impact on patient safety. Length of stay may not reflect surgeon/institution performance, as LOS is multifactorial and likely related to patient population, patient selection and increased high-risk cases with a surgeon's experience. [source] Fronto-striatal dysfunction and potential compensatory mechanisms in male adolescents with fragile X syndromeHUMAN BRAIN MAPPING, Issue 6 2007Fumiko Hoeft Abstract Response inhibition is an important facet of executive function. Fragile X syndrome (FraX), with a known genetic etiology (fragile X mental retardation-1 (FMR1) mutation) and deficits in response inhibition, may be an ideal condition for elucidating interactions among gene-brain-behavior relationships. Functional magnetic resonance imaging (fMRI) studies have shown evidence of aberrant neural activity when individuals with FraX perform executive function tasks, though the specific nature of this altered activity or possible compensatory processes has yet to be elucidated. To address this question, we examined brain activation patterns using fMRI during a go/nogo task in adolescent males with FraX and in controls. The critical comparison was made between FraX individuals and age, gender, and intelligent quotient (IQ)-matched developmentally delayed controls; in addition to a control group of age and gender-matched typically developing individuals. The FraX group showed reduced activation in the right ventrolateral prefrontal cortex (VLPFC) and right caudate head, and increased contralateral (left) VLPFC activation compared with both control groups. Individuals with FraX, but not controls, showed a significant positive correlation between task performance and activation in the left VLPFC. This potential compensatory activation was predicted by the interaction between FMR1 protein (FMRP) levels and right striatal dysfunction. These results suggest that right fronto-striatal dysfunction is likely an identifiable neuro-phenotypic feature of FraX and that activation of the left VLPFC during successful response inhibition may reflect compensatory processes. We further show that these putative compensatory processes can be predicted by a complex interaction between genetic risk and neural function. Hum Brain Mapp, 2007. © 2007 Wiley-Liss, Inc. [source] Inflammatory bowel disease: Epidemiology, pathogenesis, and therapeutic opportunitiesINFLAMMATORY BOWEL DISEASES, Issue 5 2006Stephen B Hanauer MD Abstract Ulcerative colitis (UC) and Crohn's disease (CD), the primary constituents of inflammatory bowel disease (IBD), are precipitated by a complex interaction of environmental, genetic, and immunoregulatory factors. Higher rates of IBD are seen in northern, industrialized countries, with greater prevalence among Caucasians and Ashkenazic Jews. Racial gaps are closing, indicating that environmental factors may play a role. IBD is multigenic, with the most clearly established genetic link between certain NOD2 variants and CD. Regardless of the underlying genetic predisposition, a growing body of data implicates a dysfunctional mucosal immune response to commensal bacteria in the pathogenesis of IBD, especially CD. Possible triggers include a chronic inflammatory response precipitated by infection with a particular pathogen or virus or a defective mucosal barrier. The characteristic inflammatory response begins with an infiltration of neutrophils and macrophages, which then release chemokines and cytokines. These in turn exacerbate the dysfunctional immune response and activate either TH1 or TH2 cells in the gut mucosa, respectively associated with CD and, less conclusively, with UC. Elucidation of immunological and genetic factors indicate multiple points at which the inflammatory cascade may be interrupted, yielding the possibility of precise, targeted therapies for IBD. [source] Hematological features and molecular lesions of hemoglobin gene disorders in Taiwanese patientsINTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 1p2 2010H.-J. LIN Summary Hemoglobin (Hb) gene disorders are one of the most common inherited diseases in Taiwan, which include ,-thalassemia, ,-thalassemia, and Hb variants. In this study, we collected and analyzed mutations found in 930 patients with Hb gene disorders except Hb Bart's Hydrops and ,-thalassemia major. The patients included 650 cases of ,-thalassemia, 225 cases of ,-thalassemia, 9 cases of ,-thalassemia combined with ,-thalassemia, and 46 cases of Hb variants or Hb variants combined with ,-thalassemia or ,-thalassemia. The most common type of ,0 -thalassemia and ,++ -thalassemia mutations in our study were the SEA type deletion and the ,3.7 deletion, respectively; the most common ,-thalassemia mutation was the IVS-2 nt 654 C,T mutation; and the most common Hb variant was the HbE. We compared the relationships between genotype and hematological phenotypes of various Hb gene disorders and found that different genotypes of ,0 -thalassemia have similar hematological features. In conclusion, the results of our study provide data of the complex interaction of thalassemias and Hb variants which might be useful for other researchers in this field. [source] Empowerment in social work: an individual vs. a relational perspectiveINTERNATIONAL JOURNAL OF SOCIAL WELFARE, Issue 1 2007Dag Leonardsen Social workers with only an individualistic understanding of empowerment will easily end up as moralising agents rather than as facilitators for their clients. It is in the complex interaction between a given socio-material situation and the individual capacity to interpret and act that one finds the key to an empowerment worthy of its name. This presupposes two things: that social workers have as a part of their education theoretical knowledge about organisational structures, and that they themselves have been empowered in ways that give them practical competence to act in relation to situations. They need the competence to identify the complexities of interests and power relations in society. The implication of such a recogni-tion should be clear for the education of social workers: the ideology of empowerment has to be contextualised. To discuss this topic the author makes a distinction between an individua-listic and a relational perspective and between social problems conceived of as a ,lack of money' vs. a ,lack of meaning'. [source] Institutional Diversity and Capitalist Transition: The Political Economy of Agrarian Change in Arunachal Pradesh, IndiaJOURNAL OF AGRARIAN CHANGE, Issue 4 2009BARBARA HARRISS-WHITE This paper contributes a preliminary analysis of the process of agrarian capitalist transition in Arunachal Pradesh, one of the least studied regions of India. Primarily based on information collected through a field survey in eleven villages, the paper seeks to explain the nature and implications of institutional unevenness in the development of capitalism. Institutional diversity is not simply mapped across space, it is also manifested in the simultaneous existence of market and non-market institutions across the means of production within the same village or spatial context. In addition, there is a continuous and complex interaction among these institutions which both shapes and is shaped by this capitalist transition. Primitive accumulation emerges as a continuing characteristic of the on-going agrarian and non-agrarian capitalist transition. Institutional adaptation, continuity and hybridity are as integral to the emergence of the market economy as are the processes of creation of new institutions and demise of others. There is no necessary correspondence between the emerging commercialization of the different productive dimensions of the agrarian economy. These uneven processes are deeply influenced by existing and emerging power relations and by the state. Framed by the Bernstein,Byres debate about the contemporary (ir)relevance of the agrarian question, evidence is presented to justify the conclusion that although the processes at work are far from the classical models of the transition to capitalism, all aspects of the agrarian question remain relevant. [source] | |||||||||||||||||||||||||||||||||||||