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Complex Combination (complex + combination)
Selected AbstractsPositive Interactions: Crucial Organizers in a Plant CommunityJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 2 2006Dong-Liang Cheng Abstract For more than a century, ecologists have concentrated on competition as a crucial process for community organization. However, more recent experimental investigations have uncovered the striking influence of positive interactions on the organization of plant communities. Complex combinations of competition and positive interactions operating simultaneously among plant species seem to be widespread in nature. In the present paper, we reviewed the mechanism and ecological importance of positive interactions in plant communities, emphasizing the certainties and uncertainties that have made it an attractive area of research. Positive interactions, or facilitation, occur when one species enhances the survival, growth, or richness of another. The importance of facilitation in plant organization increases with abiotic stress and the relative importance of competition decreases. Only by combining plant interactions and the many fields of biology can we fully understand how and when the positive interactions occur. (Managing editor: Ya-Qin Han) [source] Plasma Edge Physics with B2-EireneCONTRIBUTIONS TO PLASMA PHYSICS, Issue 1-2 2006R. Schneider Abstract The B2-Eirene code package was developed to give better insight into the physics in the scrape-off layer (SOL), which is defined as the region of open field-lines intersecting walls. The SOL is characterised by the competition of parallel and perpendicular transport defining by this a 2D system. The description of the plasma-wall interaction due to the existence of walls and atomic processes are necessary ingredients for an understanding of the scrape-off layer. This paper concentrates on understanding the basic physics by combining the results of the code with experiments and analytical models or estimates. This work will mainly focus on divertor tokamaks, but most of the arguments and principles can be easily adapted also to other concepts like island divertors in stellarators or limiter devices. The paper presents the basic equations for the plasma transport and the basic models for the neutral transport. This defines the basic ingredients for the SOLPS (Scrape-Off Layer Plasma Simulator) code package. A first level of understanding is approached for pure hydrogenic plasmas based both on simple models and simulations with B2-Eirene neglecting drifts and currents. The influence of neutral transport on the different operation regimes is here the main topic. This will finish with time-dependent phenomena for the pure plasma, so-called Edge Localised Modes (ELMs). Then, the influence of impurities on the SOL plasma is discussed. For the understanding of impurity physics in the SOL one needs a rather complex combination of different aspects. The impurity production process has to be understood, then the effects of impurities in terms of radiation losses have to be included and finally impurity transport is necessary. This will be introduced with rising complexity starting with simple estimates, analysing then the detailed parallel force balance and the flow pattern of impurities. Using this, impurity compression and radiation instabilities will be studied. This part ends, combining all the elements introduced before, with specific, detailed results from different machines. Then, the effect of drifts and currents is introduced and their consequences presented. Finally, some work on deriving scaling laws for the anomalous turbulent transport based on automatic edge transport code fitting procedures will be described. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Does subtle screening for substance abuse work?ADDICTION, Issue 1 2007A review of the Substance Abuse Subtle Screening Inventory (SASSI) ABSTRACT Aim Through a complex combination of direct (face-valid) and indirect (subtle) subscales, the Substance Abuse Subtle Screening Inventory (SASSI) is purported to detect substance use disorders with a high degree of validity regardless of respondent honesty or motivation. This review evaluates empirical evidence regarding the reliability and validity of this widely used screening instrument. Methods Source documents were 36 peer-reviewed reports yielding data regarding the SASSI's internal consistency, test,retest reliability, psychometric structure, convergent and divergent validity and criterion (predictive) validity. Results The total N of the studies reviewed equaled 22 110. Internal consistency is high for the overall SASSI and for its direct but not its indirect (subtle) subscales, suggesting that the instrument taps a single face-valid construct. SASSI classifications converged with those from other direct screening instruments, and were also correlated with ethnicity, general distress and social deviance. Studies found test,retest reliability lower than that reported in the test manuals. Sensitivity was found to be similar to that for public domain screening instruments, but on specificity the SASSI appears to yield a high rate of false positives. Conclusion No empirical evidence was found for the SASSI's claimed unique advantage in detecting substance use disorders through its indirect (subtle) scales to circumvent respondent denial or dishonesty. Recommendations for screening and for future research with the SASSI are offered. [source] Direct cell,cell interactions control apoptosis and oligodendrocyte marker expression of neuroepithelial cellsJOURNAL OF NEUROSCIENCE RESEARCH, Issue 3 2001J.P. Hugnot Abstract During brain development, the neuroepithelium generates neurons and glial cells. Proliferation and differentiation of neuroepithelial cells are controlled by a complex combination of secreted factors and more intrinsic or local mechanisms, such as lateral inhibition and asymmetric division. To obtain further insights into the signals governing neuroepithelial cell fate, we used the immortomouse to derive conditionally immortalised cell lines from mouse E10 neuroepithelium. We isolated a nestin-positive basic fibroblast growth factor (bFGF)-responsive cell line (SVE10-23) which mostly differentiate into astrocytes when cocultured with primary cortical cells. We found that, by simply lowering the cell density, SVE10-23 cells embarked on oligodendrocytic differentiation as indicated by the strong expression of galactocerebroside C and 2,3,-cyclic nucleotide 3,-phosphodiesterase. Apoptosis accompanied the differentiation, and all cells died within 1 week. We present here evidence that direct interactions between cells are the main mechanism regulating this oligodendrocytic differentiation. We demonstrate that SVE10-23 cells contact or proximity inhibit their differentiation, prevent apoptosis, and promote their proliferation. Similarly, others nestin-positive precursor cell lines and nonimmortalised bFGF-grown E10 cells were found to spontaneously differentiate at low density, thus generalising the idea that neural precursor fate is regulated by direct cell,cell interactions. The SVE10-23 cell line provides a valuable tool with which to study further the molecular components implicated in this mode of regulation. J. Neurosci. Res. 65:195,207, 2001. © 2001 Wiley-Liss, Inc. [source] Understanding the shapes of bacteria just got more complicatedMOLECULAR MICROBIOLOGY, Issue 1 2006Terry J. Beveridge Summary The paper by Briegel et al. in this issue of Molecular Microbiology uses advanced cryo-transmission electron microscopy (cryoTEM) techniques to reveal four separate locations of cytoplasmic filament bundles in Caulobacter crescentus. Intuitively, these filaments should be rather rigid protein structures and composed of previously identified shape-forming proteins, such as crescentin or MreB. Yet, deletion mutants lacking these proteins still possessed filaments and still possessed wild-type morphology. These results suggest that a complex combination of protein structures, including those of crescentin, MreB and these newly identified bundles, in combination with the cell envelope help maintain the complicated shape of C. crescentus. Other bacteria might have similar architectural proteins to assist in maintaining the cell contours during growth and division. [source] Bladder dysfunction in Parkinsonism: Mechanisms, prevalence, symptoms, and managementMOVEMENT DISORDERS, Issue 6 2006Kristian Winge MD Abstract The advent of functional imaging methods has increased our understanding of the neural control of the bladder. This review examines current concepts of the role of brain function in urinary control with particular emphasis on the putative role of dopamine receptors. Dopaminergic mechanisms play a profound role in normal bladder control and the dysfunction of these may result in symptoms of overactive bladder in Parkinsonism. The importance of this nonmotor disorder has been overlooked. We address the problem of bladder dysfunction as it presents to patients and their neurologist. The prevalence of bladder symptoms in Parkinson's disease is high; the most common complaint is nocturia followed by frequency and urgency. In multiple-system atrophy, the combination of urge and urge incontinence and poor emptying may result in a complex combination of complaints. The management of bladder dysfunction in Parkinsonism addresses treatment of overactive detrusor as well as incontinence. © 2006 Movement Disorder Society [source] Spatial Govemmentality and the New Urban Social Order: Controlling Gender Violence through LawAMERICAN ANTHROPOLOGIST, Issue 1 2001Sally Engle Merry The new urban social order depends on a complex combination of systems of punishment, discipline, and security. Scholars drawing on Foucault's analysis of the art and rationality of governance, or govemmentality, have explored how urban social orders are increasingly based on the governance of space rather than on the discipline of offenders or the punishment of offenses. The new urban social order is characterized by privatized security systems and consumer-policed spaces such as malls. Gender violence interventions represent another deployment of spatial forms of govemmentality. Over the last two decades, punishment of batterers has been augmented by disciplinary systems that teach batterers new forms of masculinity and by security systems for women based on spatial separation. In the postmodern city, spatial govemmentality is integrally connected with punishment and discipline. These new forms of governance circulate globally along with neoliberal ideas of the diminished state, [gender violence, govemmentality, urban society, globalization, law] [source] Perception and practice of child labour among parents of school-aged children in Ibadan, southwest NigeriaCHILD: CARE, HEALTH AND DEVELOPMENT, Issue 3 2010F. O. Omokhodion Abstract Background The problem of child labour has lingered on in many countries because of the complex combination of social, cultural and economic factors involved. Parents play a critical role in child labour as it provides much needed extra income for the family. This study was carried out among parents of school-aged children in an urban, low-income community to determine the factors associated with child labour and attitudes to child labour in the community. Methods A cross-sectional study was carried out in an urban community in Ibadan, southwest Nigeria. Questionnaires were administered to parents of school-aged children. Results A total of 473 parents were interviewed. They were aged between 23 and 56 years, mean 37.9 years. Thirty-nine per cent of parents indicated that they thought their school-aged children should work. More women than men, those from polygamous homes and those with lower educational status held this view. Reasons given for wanting their children to work were to supplement family income, 45%, to gain experience, 35% and to help in family business, 10%. In all, 236 (50%) respondents reported that their school-aged children were working. Parental factors associated with practice of child labour were polygamous marriage, low educational status, unskilled or partly skilled occupation and large family size. Seventeen per cent of parents with working children were not satisfied with their children's work conditions and complained of low earnings, long working hours, work on school days and unsafe work environment. Measures suggested to control child labour include addressing the issue of household poverty, public enlightenment about the ills of child labour and free education up to junior secondary level. Enforcement of child labour laws was the least mentioned. Conclusion We conclude that control of child labour should be a multifaceted approach involving poverty alleviation, family planning to reduce family size and free, compulsory education up to junior secondary level. Public enlightenment especially for mothers will be of additional benefit. [source] The cells and mediators of allergic inflammationCLINICAL & EXPERIMENTAL ALLERGY REVIEWS, Issue 1 2002A. B. Kay Summary In sensitized atopic subjects allergen administration results in an immediate-type reaction and, depending on the dose of the allergen, an additional late-phase reaction. The early reaction results largely from the release of histamine, leukotrienes and other mediators from mast cells. The cutaneous late-phase reaction is probably also predominantly mast-cell-dependent. The late asthmatic reaction, however, also involves T-cell activation. T cells release a cascade of factors which evoke the migration of many cell types, including eosinophils, neutrophils and macrophages into the site of inflammation, under the influence of a complex combination of cytokines and chemokines. Neural inflammation (i.e. neuropeptides and neurotrophins) may also be involved. The identification of the processes underlying the inflammatory response to allergens, and their control mechanisms, provides specific targets for therapeutic measures (such as the use of monoclonal antibodies and soluble receptor molecules) which are designed to impede or abolish the allergic inflammatory cascade. [source] ,-thalassaemia masked by , gene defects and a new polyadenylation site mutation on the ,2-globin geneEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 4 2010Cornelis L. Harteveld Abstract We report three examples of chronic anaemia involving complex combinations of ,- and ,-globin gene defects. The first case had a potential Hb H disease caused by the classic SEA/RW deletions masked by Hb E [,26(B8)Glu,Lys] in the homozygous state. The second had an unusual Hb H disease caused by compound heterozygosity for two different ,2 polyadenylation site mutations masked by a ,-thalassaemia heterozygosity. The third had an intermediate ,-thalassaemia with considerable anaemia caused by an as yet unknown polyadenylation site (AATAAA>AATAAC) mutation in combination with a common RW deletion masked by a common Hb C [,6(A3)Glu,Lys] heterozygosity. Diagnostic methods, genotype/phenotype correlations and the chance of overlooking these combinations during risk assessment in a multiethnic society are discussed. [source] ,It Takes Two Hands to Clap': How Gaddi Shepherds in the Indian Himalayas Negotiate Access to GrazingJOURNAL OF AGRARIAN CHANGE, Issue 1 2007RICHARD AXELBY This article examines the effects of state intervention on the workings of informal institutions that coordinate the communal use and management of natural resources. Specifically it focuses on the case of the nomadic Gaddi shepherds and official attempts to regulate their access to grazing pastures in the Indian Himalayas. It is often predicted that the increased presence of the modern state critically undermines locally appropriate and community-based resource management arrangements. Drawing on the work of Pauline Peters and Francis Cleaver, I identify key instances of socially embedded ,common' management institutions and explain the evolution of these arrangements through dynamic interactions between individuals, communities and the agents of the state. Through describing the ,living space' of Gaddi shepherds across the annual cycle of nomadic migration with their flocks I explore the ways in which they have been able to creatively reinterpret external interventions, and suggest how contemporary arrangements for accessing pasture at different moments of the annual cycle involve complex combinations of the formal and the informal, the ,traditional' and the ,modern'. [source] Magnebike: A magnetic wheeled robot with high mobility for inspecting complex-shaped structuresJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 5 2009Fabien Tāche This paper describes the Magnebike robot, a compact robot with two magnetic wheels in a motorbike arrangement, which is intended for inspecting the inner casing of ferromagnetic pipes with complex-shaped structures. The locomotion concept is based on an adapted magnetic wheel unit integrating two lateral lever arms. These arms allow for slight lifting off the wheel in order to locally decrease the magnetic attraction force when passing concave edges, as well as laterally stabilizing the wheel unit. The robot has the main advantage of being compact (180 × 130 × 220 mm) and mechanically simple: it features only five active degrees of freedom (two driven wheels each equipped with an active lifter stabilizer and one steering unit). The paper presents in detail design and implementation issues that are specific to magnetic wheeled robots. Low-level control functionalities are addressed because they are necessary to control the active system. The paper also focuses on characterizing and analyzing the implemented robot. The high mobility is shown through experimental results: the robot not only can climb vertical walls and follow circumferential paths inside pipe structures but it is also able to pass complex combinations of 90-deg convex and concave ferromagnetic obstacles with almost any inclination regarding gravity. It requires only limited space to maneuver because turning on the spot around the rear wheel is possible. This high mobility enables the robot to access any location in the specified environment. Finally the paper analyzes the maximum payload for different types of environment complexities because this is a key feature for climbing robots and provides a security factor about the risk of falling and slipping. © 2009 Wiley Periodicals, Inc. [source] Chloroquine resistance in the malarial parasite, Plasmodium falciparumMEDICINAL RESEARCH REVIEWS, Issue 5 2002Lyann M.B. Ursos Abstract Malarial parasites remain a health problem of staggering proportions. Worldwide, they infect about 500 million, incapacitate tens of millions, and kill approximately 2.5 million (mostly children) annually. Four species infect humans, but most deaths are caused by one particular species, Plasmodium falciparum. The rising number of malarial deaths is due in part to increased drug resistance in P. falciparum. There are many varieties of antimalarial drug resistance, and there may very well be several molecular level contributions to each variety. This is because there are a number of different drugs with different mechanisms of action in use, and more than one molecular event may sometimes be relevant for resistance to any one class of drugs. Thus, "multidrug" resistance in a clinical setting likely entails complex combinations of overlapping resistance pathways, each specific for one class of drug, that then add together to confer the particular multidrug resistance phenotype. Nonetheless, rapid progress has been made in recent years in elucidating mechanisms of resistance to specific classes of antimalarial drugs. As one example, resistance to the antimalarial drug chloroquine, which has been the mainstay therapy for decades, is becoming well understood. This article focuses on recent advances in determining the molecular mechanism of chloroquine resistance, with particular attention to the biochemistry and biophysics of the P. falciparum digestive vacuole, wherein changes in pH have recently been found to be associated with chloroquine resistance. © 2002 Wiley Periodicals, Inc. Med Res Rev, 22, No. 5, 465,491, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/med.10016 [source] Modelling prior reproductive history to improve prediction of risk for very preterm birthPAEDIATRIC & PERINATAL EPIDEMIOLOGY, Issue 5 2010Lyndsey F. Watson Summary Watson LF, Rayner J-A, King J, Jolley D, Forster D, Lumley J. Modelling prior reproductive history to improve prediction of risk for very preterm birth. Paediatric and Perinatal Epidemiology 2010. In published studies of preterm birth, analyses have usually been centred on individual reproductive events and do not account for the joint distributions of these events. In particular, spontaneous and induced abortions have often been studied separately and have been variously reported as having no increased risk, increased risk or different risks for subsequent preterm birth. In order to address this inconsistency, we categorised women into mutually exclusive groups according to their reproductive history, and explored the range of risks associated with different reproductive histories and assessed similarities of risks between different pregnancy histories. The data were from a population-based case,control study, conducted in Victoria, Australia. The study recruited women giving birth between April 2002 and April 2004 from 73 maternity hospitals. Detailed reproductive histories were collected by interview a few weeks after the birth. The cases were 603 women who had had a singleton birth between 20 and less than 32 weeks gestation (very preterm births including terminations of pregnancy) and the controls were 796 randomly selected women from the population who had had a singleton birth of at least 37 completed weeks gestation. All birth outcomes were included. Unconditional logistic regression was used to assess the association of very preterm birth with type and number of prior abortions, prior preterm births and sociodemographic factors. Using the complex combinations of prior pregnancy experiences of women (including nulligravidity), we showed that a history of prior childbirth (at term) with no preterm births gave the lowest risk of very preterm birth. With this group as the reference category, odds ratios of more than two were associated with all other prior reproductive histories. There was no evidence of difference in risk between types of abortion (i.e. spontaneous or induced) although the risk increased if a prior preterm birth had also occurred. There was an increasing risk of very preterm birth associated with increasing numbers of abortions. This method of data analysis reveals consistent and similar risks for very preterm birth following spontaneous or induced abortions. The findings point to the need to explore commonalities rather than differences in regard to the impact of abortion on subsequent births. [source] | ||||||||||||||||