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Effect Relationships (effect + relationships)
Selected AbstractsUse of paired fathead minnow (Pimephales promelas) reproductive test.ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2006Part 1: Assessing biological effects of final bleached kraft pulp mill effluent using a mobile bioassay trailer system Abstract Reproductive effects have been recorded in wild fish in waters receiving pulp mill effluent (PME) since the mid to late 1980s. Laboratory assays with fathead minnow (FHM; Pimephales promelas) have been developed to better understand fish responses to PME. However, observations from laboratory studies have been variable, making it difficult to establish cause/effect relationships. A lack of environmental relevance in these laboratory studies may have contributed to the variability observed. The objectives of the present study were, first, to determine the effects of bleached kraft PME (BKME) on FHM under environmentally realistic conditions (i.e., ambient water and effluent quality) and, second, to determine the suitability of pair-breeding FHM to better link BKME-induced changes in indicators at the biochemical, individual, and population levels. A mobile bioassay trailer was situated on-site at a bleached kraft mill for 60 d, allowing supply of both ambient water (Lake Superior, Canada) and final BKME. The reproductive output of FHM was initially assessed for 21 d to obtain baseline data pre-exposure. At the end of the pre-exposure period, selected breeding pairs were exposed to final BKME (100% v/v and 1% v/v) for 21 d. Results demonstrated a stimulatory response pattern at 1% BKME (e.g., increased egg production) compared to control. In the 100% treatment, spawning events were reduced and fewer eggs were produced during the first two weeks of exposure. Exposure to 100% (v/v) BKME also resulted in ovipositor development in males and development of male secondary sex characteristics in females. Obtaining pre-exposure data and use of pair-breeding FHM in this assay gave a sensitive indication of effluent effects and allowed accurate comparisons of endpoints to be made. [source] Processing Energy and Signals by Molecular and Supramolecular SystemsCHEMISTRY - A EUROPEAN JOURNAL, Issue 1 2008Vincenzo Balzani Prof. Abstract Any kind of device or machine requires a substrate, energy, and information signals. If we wish to operate at the nanometer scale, we must use molecules as substrates. Energy- and signal-processing at a molecular level relies on cause/effect relationships between the input supplied and the kind of process obtained. We have classified energy- and signal-processing at the molecular level according to the nature of the input (electronic, photonic, or chemical) and the nature of the obtained effect (electronic, photonic, or chemical process that follows). By coupling the three kinds of inputs with the three types of resulting processes, nine types of molecular-based processes (electronic, photonic, chemionic, electrophotonic, electrochemionic, photoelectronic, photochemionic, chemiophotonic, and chemioelectronic) can be identified. In this concept article, looking at molecular transformations in an unconventional way, we have tried to give a flavor of some of the new features that project the old science of chemistry towards novel achievements. [source] Lithium treatment in Aarhus: contributions and controversies through half a centuryACTA PSYCHIATRICA SCANDINAVICA, Issue 2004Per Vestergaard In 1954 the first of several hundred publications on the use of lithium for treatment of affective disorders, lithium's unwanted effects, and its pharmacology was authored at the Aarhus University Psychiatric Hospital, the majority with Professor, now emeritus, Mogens Schou playing the principal part. The early part of this long series of papers highlights the pharmacology of lithium with its renal excretion, low therapeutic index, and ensuing risk of intoxication, the prophylactic effect not only against manic episodes but also the depressive ones and finally the long-term renal structural and functional impairment. Later papers present the problems related to lithium's lower effectiveness in routine clinical use, the problems of non-adherence, the dose effect relationships, and the problems inherent to establishing effective treatment service delivery. The present priority of the Aarhus lithium group is the simple large scale pragmatic effectiveness studies in which, together with domestic and foreign collaborators, we compare the long-term effectiveness of lithium with new promising drugs with mood stabilizing properties. The story of treatment with lithium in aarhus highlights important steps in the development of effective and comprehensive treatments for bipolar patients. [source] Integrated condition indices as a measure of whole effluent toxicity in zebrafish (Danio rerio)ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 1 2002Roel Smolders Abstract Toxic exposure of organisms interferes with organismal integrity at the biochemical level and ultimately gives rise to effects at the individual level. These effects may result in reductions in ecologically relevant characteristics such as growth, reproduction, and survival. A chronic toxicity test with zebrafish (Danio rerio) was conducted where fish were exposed to 50, 75, and 100% effluent for 28 d under flow-through conditions. Effects of effluent exposure were determined using endpoints of physiological (respiration during swimming), growth (condition, length, and weight), and reproductive (spawning and hatching) processes within the same population. Results clearly indicate that the condition and growth of zebrafish is depressed by exposure to the effluent. Also, increased oxygen consumption was found after 14, 21, and 28 d of exposure. Reproduction proved to correlate well with the condition of the motherfish in the control, and spawning and hatching were significantly depressed by effluent exposure. These results indicate that the evaluation of endpoints describing different ecologically relevant processes provides a rational assessment of the cause,effect relationships of effluent toxicity. This approach can quantify effects on different biological processes and can determine the interactions that occur between these different processes. [source] Interface Engineering of Inorganic Thin-Film Solar Cells , Materials-Science Challenges for Advanced Physical ConceptsADVANCED MATERIALS, Issue 42 2009Wolfram Jaegermann Abstract The challenges and research needs for the interface engineering of thin-film solar cells using inorganic-compound semiconductors are discussed from a materials-science point of view. It is, in principle, easily possible to define optimized device structures from physical considerations. However, to realize these structures, many materials' limitations must be overcome by complex processing strategies. In this paper, interface properties and growth morphology are discussed using CdTe solar cells as an example. The need for a better fundamental understanding of cause,effect relationships for improving thin-film solar cells is emphasized. [source] From dynamic influence nets to dynamic Bayesian networks: A transformation algorithmINTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 8 2009Sajjad Haider This paper presents an algorithm to transform a dynamic influence net (DIN) into a dynamic Bayesian network (DBN). The transformation aims to bring the best of both probabilistic reasoning paradigms. The advantages of DINs lie in their ability to represent causal and time-varying information in a compact and easy-to-understand manner. They facilitate a system modeler in connecting a set of desired effects and a set of actionable events through a series of dynamically changing cause and effect relationships. The resultant probabilistic model is then used to analyze different courses of action in terms of their effectiveness to achieve the desired effect(s). The major drawback of DINs is their inability to incorporate evidence that arrive during the execution of a course of action (COA). Several belief-updating algorithms, on the other hand, have been developed for DBNs that enable a system modeler to insert evidence in dynamic probabilistic models. Dynamic Bayesian networks, however, suffer from the intractability of knowledge acquisition. The presented transformation algorithm combines the advantages of both DINs and DBNs. It enables a system analyst to capture a complex situation using a DIN and pick the best (or close-to-best) COA that maximizes the likelihood of achieving the desired effect. During the execution, if evidence becomes available, the DIN is converted into an equivalent DBN and beliefs of other nodes in the network are updated. If required, the selected COA can be revised on the basis of the recently received evidence. The presented methodology is applicable in domains requiring strategic level decision making in highly complex situations, such as war games, real-time strategy video games, and business simulation games. © 2009 Wiley Periodicals, Inc. [source] Cautions and Concerns in Experimental Research on the Consumer InterestJOURNAL OF CONSUMER AFFAIRS, Issue 3 2008MARLA B. ROYNE Most published consumer research presents data from surveys or other data analyses that, at best, report that certain things tend to happen at the same time. However, correlation does not mean causation; cause and effect relationships can only be concluded from controlled experiments. A key problem is that the use of experimental designs calls for various conceptual and pragmatic trade-offs that cannot be ignored. [source] Causal inference with generalized structural mean modelsJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES B (STATISTICAL METHODOLOGY), Issue 4 2003S. Vansteelandt Summary., We estimate cause,effect relationships in empirical research where exposures are not completely controlled, as in observational studies or with patient non-compliance and self-selected treatment switches in randomized clinical trials. Additive and multiplicative structural mean models have proved useful for this but suffer from the classical limitations of linear and log-linear models when accommodating binary data. We propose the generalized structural mean model to overcome these limitations. This is a semiparametric two-stage model which extends the structural mean model to handle non-linear average exposure effects. The first-stage structural model describes the causal effect of received exposure by contrasting the means of observed and potential exposure-free outcomes in exposed subsets of the population. For identification of the structural parameters, a second stage ,nuisance' model is introduced. This takes the form of a classical association model for expected outcomes given observed exposure. Under the model, we derive estimating equations which yield consistent, asymptotically normal and efficient estimators of the structural effects. We examine their robustness to model misspecification and construct robust estimators in the absence of any exposure effect. The double-logistic structural mean model is developed in more detail to estimate the effect of observed exposure on the success of treatment in a randomized controlled blood pressure reduction trial with self-selected non-compliance. [source] Linaclotide , a secretagogue and antihyperalgesic agent , what next?NEUROGASTROENTEROLOGY & MOTILITY, Issue 3 2010A. E. Bharucha Abstract Ongoing clinical trials suggest that linaclotide, a first-in-class, 14-amino acid peptide guanylate cyclase-C (GC-C) receptor agonist and intestinal secretagogue is an effective treatment for chronic constipation. A study in this issue of the Journal suggests that linaclotide also has antihyperalgesic effects in three common rat models of inflammation- and stress-induced hypersensitivity (i.e., acute trinitrobenzene sulfonic acid colitis, water avoidance stress [WAS], and restraint-induced stress) but not in naïve animals. In mice, linaclotide at least partly reduces hyperalgesia via GC-C receptors. Dose,effect relationships of linaclotide were complicated and non-linear. This viewpoint discusses human clinical trials with linaclotide and the results of this study. Potential mechanisms and clinical significance of these findings are explored. Collectively, these data suggest that GC-C receptors exert other, as yet poorly understood, effects on gastrointestinal sensitivity in conditions associated with inflammation and/or stress-induced increased intestinal permeability. However, the data need to be confirmed in humans and in long-term animal models. Further studies are also necessary to elucidate the mechanisms as these effects cannot be explained by linaclotide's known effects on epithelial GC-C receptors. [source] Biomarkers of Mn exposure in humansAMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 11 2007Donald Smith PhD Abstract Background Studies have reported associations between manganese (Mn) exposures and Mn levels in blood and urine, though the suitability of these biological measures as biomarkers of exposure is not well known. Methods We evaluated whether whole blood, plasma, and urine Mn levels reflect exposures in occupationally exposed humans. Results In active ferroalloy workers, blood Mn was associated with total air Mn levels in subjects currently exposed to low (median,=,0.42 ,g/m3, P,=,0.009) and moderate (median,=,4.2 ,g/m3, P,=,0.007) air Mn levels, but not in workers exposed to the highest Mn levels (median,=,292 ,g/m3, P,=,0.31). In bridge welders blood Mn (P,<,0.01), but not plasma or urine Mn was significantly associated with their cumulative respiratory exposure index. In welders, ,6% (range ,3,9%) of whole blood Mn was contained in the plasma fraction, though there was no association between whole blood and plasma Mn levels (Pearson's R,=,0.258, P,=,0.12). In contrast, in fresh whole blood samples spiked with Mn ex vivo ,80% or more of added Mn partitioned in the plasma, while only ,20% or less partitioned in the cellular fraction. Conclusions These data suggest a complex and limited relationship between exposure and blood Mn levels that may depend upon exposure attributes and the latency of blood sampling relative to exposure; plasma and urine Mn appear to be of little utility as exposure biomarkers. This underscores the need to fully characterize and validate these or other biomarkers for use in constructing appropriate exposure metrics and determining exposure,effect relationships. Am. J. Ind. Med. 50:801,811, 2007. © 2007 Wiley-Liss, Inc. [source] Joseph M. Juran, a perspective on past contributions and future impactQUALITY AND RELIABILITY ENGINEERING INTERNATIONAL, Issue 6 2007A. Blanton Godfrey Abstract This paper combines presentations by the authors in a special session dedicated to the work of Joseph M. Juran at the sixth annual conference of the European Network for Business and Industrial Statistics in Wroclaw, Poland. The paper offers an historical perspective of the contributions of J. M. Juran to management science emphasizing aspects of cause and effect relationships and Integrated Models. Specifically, the paper presents the Juran concepts of Management Breakthrough, the Pareto Principle, the Juran Trilogy® and Six Sigma. The impact of these contributions, put in an historical perspective of key thinkers who investigated cause and effect relationships, is then discussed. The impact of these contributions to modern Integrated Models is then assessed. Copyright © 2007 John Wiley & Sons, Ltd. [source] Conversing with pedagogical agents: A phenomenological exploration of interacting with digital entitiesBRITISH JOURNAL OF EDUCATIONAL TECHNOLOGY, Issue 6 2008George Veletsianos In this paper, we examine the meaning of conversing with pedagogical agents. Previous research has focused on examining cause and effect relationships, failing to take into account the meaning of the experiences individuals have when holding a dialogue with conversational agents for educational purposes. To understand these experiences, we have conducted a phenomenological examination of what it means to converse with a pedagogical agent. In phenomenological terms, findings suggest the experience is complex, engrossing, virtual yet real, human-like, and social. Implications for the future design, implementation, and research of conversational agents in educational and other settings are discussed. [source] Pharmacokinetic-pharmacodynamic modelling in the early development phase of anti-psychotics: a comparison of the effects of clozapine, S 16924 and S 18327 in the EEG model in ratsBRITISH JOURNAL OF PHARMACOLOGY, Issue 1 2001T J Parker The use of pharmacokinetic/pharmacodynamic (PK/PD) analysis in early compound development was investigated in the rat for two developmental anti-psychotic compounds with clozapine as a positive control. Three plasma samples were collected from each of eight animals according to a pre-defined sampling matrix allowing a total of 12 time points for PK analysis. Quantitative electroencephalography (QEEG), particularly the theta and beta frequencies, was used as a measurement of pharmacological effect. PK/KD modelling of the sparse PK data available relative to a rich set of PD data was achieved using a population approach in NONMEM (IV). Individual PK parameter estimates were incorporated into a PK/PD model. Qualitative EEG changes in rat and human were similar for clozapine, but different for the two developmental compounds, suggesting that changes in these PD parameters may not be specifically related to the anti-psychotic activity. Although no definitive data are available concerning the signal specificity of EEG frequency bands with respect to dopaminergic or serotonergic receptor activity, qualitative and quantitative differences seen in EEG parameters are likely to result from the multiple receptor occupancy for these compounds. The results confirm the value of population PK/PD modelling in conjunction with sparse sampling to enable determination of concentration effect relationships in the pre-clinical development programme of CNS-active drugs. British Journal of Pharmacology (2001) 132, 151,158; doi:10.1038/sj.bjp.0703791 [source] | ||||||||||