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Selected AbstractsDevelopment and evaluation of consensus-based sediment effect concentrations for polychlorinated biphenyls,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 5 2000Donald D. MacDonald Abstract Sediment-quality guidelines (SQGs) have been published for polychlorinated biphenyls (PCBs) using both empirical and theoretical approaches. Empirically based guidelines have been developed using the screening-level concentration, effects range, effects level, and apparent effects threshold approaches. Theoretically based guidelines have been developed using the equilibrium-partitioning approach. Empirically-based guidelines were classified into three general categories, in accordance with their original narrative intents, and used to develop three consensus-based sediment effect concentrations (SECs) for total PCBs (tPCBs), including a threshold effect concentration, a midrange effect concentration, and an extreme effect concentration. Consensus-based SECs were derived because they estimate the central tendency of the published SQGs and, thus, reconcile the guidance values that have been derived using various approaches. Initially, consensus-based SECs for tPCBs were developed separately for freshwater sediments and for marine and estuarine sediments. Because the respective SECs were statistically similar, the underlying SQGs were subsequently merged and used to formulate more generally applicable SECs. The three consensus-based SECs were then evaluated for reliability using matching sediment chemistry and toxicity data from field studies, dose-response data from spiked-sediment toxicity tests, and SQGs derived from the equilibrium-partitioning approach. The results of this evaluation demonstrated that the consensus-based SECs can accurately predict both the presence and absence of toxicity in field-collected sediments. Importantly, the incidence of toxicity increases incrementally with increasing concentrations of tPCBs. Moreover, the consensus-based SECs are comparable to the chronic toxicity thresholds that have been estimated from dose-response data and equilibrium-partitioning models. Therefore, consensus-based SECs provide a unifying synthesis of existing SQGs, reflect causal rather than correlative effects, and accurately predict sediment toxicity in PCB-contaminated sediments. [source] Colloidal Films That Mimic CiliaADVANCED FUNCTIONAL MATERIALS, Issue 18 2010Fang Liu Abstract Cilia are wavy hair-like structures that extend outward from surfaces of various organisms. They are classified into two general categories, primary cilia, which exhibit sensing attributes, and motile cilia, which exert mechanical forces. A new poly(2-(N,N -dimethylamino)ethyl methacrylate- co -n-butyl acrylate- co - N,N -(dimethylamino) azobenzene acrylamide) (p(DMAEMA/nBA/DMAAZOAm) copolymer is prepared using colloidal synthesis, which, upon coalescence, form films capable of generating surfaces with cilia-like features. While film morphological features allow the formation of wavy whiskers, the chemical composition of the copolymer facilitates chemical, thermal, and electromagnetic responses manifested by simultaneous shape and color changes as well as excitation wavelength dependent fluorescence. These studies demonstrate that synthetically produced polymeric films can exhibit combined thermal, chemical, and electromagnetic sensing leading to locomotive and color responses, which may find numerous applications in sensing devices, intelligent actuators, defensive mechanisms, and others. [source] Multiple testing in the genomics era: Findings from Genetic Analysis Workshop 15, Group 15GENETIC EPIDEMIOLOGY, Issue S1 2007Lisa J. Martin Abstract Recent advances in molecular technologies have resulted in the ability to screen hundreds of thousands of single nucleotide polymorphisms and tens of thousands of gene expression profiles. While these data have the potential to inform investigations into disease etiologies and advance medicine, the question of how to adequately control both type I and type II error rates remains. Genetic Analysis Workshop 15 datasets provided a unique opportunity for participants to evaluate multiple testing strategies applicable to microarray and single nucleotide polymorphism data. The Genetic Analysis Workshop 15 multiple testing and false discovery rate group (Group 15) investigated three general categories for multiple testing corrections, which are summarized in this review: statistical independence, error rate adjustment, and data reduction. We show that while each approach may have certain advantages, adequate error control is largely dependent upon the question under consideration and often requires the use of multiple analytic strategies. Genet. Epidemiol. 31(Suppl. 1):S124,S131, 2007. © 2007 Wiley-Liss, Inc. [source] Review of validation of the discontinuous deformation analysis (DDA) methodINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 4 2006M. M. MacLaughlin Abstract Over the last decade, researchers in the discontinuous deformation analysis (DDA) community have dedicated a great deal of effort to document the accuracy of the method by performing validation studies. This paper contains a summary of more than 100 published and unpublished validation studies which comprise the body of DDA validation information to which the authors have access. The studies are grouped into three general categories: (a) validation with respect to analytical solutions, (b) validation with respect to results of other numerical techniques, and (c) validation with respect to laboratory and field data. Three general techniques for validation are described: qualitative assessment visually examining runtime behaviour of simulations, semi-quantitative assessment comparing numerical results of simulations, and quantitative where numerical simulation results are evaluated in detail with respect to similar analytical, laboratory or field results. We find that for many of the problems addressed by the papers in this review, DDA performs more than adequately for engineering analysis. Copyright © 2006 John Wiley & Sons, Ltd. [source] Biological Indicator Systems in Floodplains , a ReviewINTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 4 2006Frank Dziock Abstract Based on a literature review, the different approaches to biological indicator systems in floodplains are summarised. Four general categories of bioindication are defined and proposed here: 1. Classification indicators, 2.1 Environmental indicators, 2.2 Biodiversity indicators, 3. Valuation indicators. Furthermore, existing approaches in floodplains are classified according to the four categories. Relevant and widely used approaches in floodplains are explained in more detail. The results of the RIVA project are put into the context of these indication approaches. It is concluded that especially functional assessment approaches using biological traits of the species can be seen as very promising and deserve more attention by conservation biologists and floodplain ecologists. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Application of otolith microchemistry to estimate the migratory history of Japanese eel Anguilla japonica on the Sanriku Coast of JapanJOURNAL OF APPLIED ICHTHYOLOGY, Issue 2 2004A. Kotake Summary The age and migratory history of the Japanese eel, Anguilla japonica Temminck & Schlegel, collected in Miyako Bay along the Sanriku coast of Japan, was examined using the otolith microstructure and analysis of strontium (Sr) and calcium (Ca) concentrations conducted with wavelength dispersive X-ray spectrometry by an electron microprobe. The line analysis of Sr : Ca ratios along the life history transect of each otolith showed a peak (ca. 15,17 × 10,3) which corresponded with the period of their leptocephalus and early glass eel stages in the ocean. The mean Sr : Ca ratios from the elver mark to the otolith edge indicated that there were eels with several general categories of migratory history, including sea eels that never entered freshwater (average Sr : Ca ratios, ,6.0 × 10,3), and others that entered freshwater for brief periods but returned to the estuary or bay. This evidence of the occurrence of sea eels in this northern area indicates that Japanese eels of the Sanriku coast do not necessarily migrate into freshwater rivers during recruitment as do glass eels at the beginning of their growth phase; even those that do enter freshwater may later return to the marine environment. Thus, anguillid eel migrations into freshwater are clearly not an obligatory migratory pathway, but rather a facultative catadromy with seawater or estuarine residents as an ecophenotype. [source] The evolution of cooperation and altruism , a general framework and a classification of modelsJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 5 2006L. LEHMANN Abstract One of the enduring puzzles in biology and the social sciences is the origin and persistence of intraspecific cooperation and altruism in humans and other species. Hundreds of theoretical models have been proposed and there is much confusion about the relationship between these models. To clarify the situation, we developed a synthetic conceptual framework that delineates the conditions necessary for the evolution of altruism and cooperation. We show that at least one of the four following conditions needs to be fulfilled: direct benefits to the focal individual performing a cooperative act; direct or indirect information allowing a better than random guess about whether a given individual will behave cooperatively in repeated reciprocal interactions; preferential interactions between related individuals; and genetic correlation between genes coding for altruism and phenotypic traits that can be identified. When one or more of these conditions are met, altruism or cooperation can evolve if the cost-to-benefit ratio of altruistic and cooperative acts is greater than a threshold value. The cost-to-benefit ratio can be altered by coercion, punishment and policing which therefore act as mechanisms facilitating the evolution of altruism and cooperation. All the models proposed so far are explicitly or implicitly built on these general principles, allowing us to classify them into four general categories. [source] Comparing Frequent and Average Users of Elementary School-Based Health Centers in the Bronx, New York CityJOURNAL OF SCHOOL HEALTH, Issue 4 2002Raymundo S. Baquiran ABSTRACT: This study analyzed health care utilization at three school-based health centers (SBHCs) in the Bronx, New York City, and compared characteristics of "frequent" and "average" service users. Encounter form data for visits by 2,795 students who received services at least once between September 7, 1998, and June 30, 1999, were reviewed. Demographic comparisons between clinic users and the total school population, and between "frequent" (five or more visits/year) and "average" (one to four visits/year) users were made. The two groups also were compared after primary diagnoses were classified into five general categories. Some 96% (3,469/3,614) of students were registered in the SBHCs, of whom 81% (2,795/3,469) used clinic services at least once during the school year. Clinic users did not differ from the general school population by gender, but were younger (p < 0.01). "Frequent" users were more likely than "average" users to be older (p < 0.01), but they did not differ by gender, race/ethnicity, or insurance status. "Frequent" users comprised 28% of the clinic-using population, but accounted for 72.5% of all visits. Similarly, "average" users comprised 72.4% of the clinic-using population, but accounted for 27.5% of all visits. "Frequent" users generated most visits for mental health and chronic medical conditions, while "average" users generated most visits for preventive care, acute medical care, and injuries/emergencies (p < 0.01 for all). Important challenges for elementary SBHCs include developing new approaches that meet children's needs while protecting clinic resources, like scheduling group interventions for those with on-going health care needs who require frequent use of school health services. [source] Responding to Roommate Troubles: Reconsidering Informal Dyadic ControlLAW & SOCIETY REVIEW, Issue 3 2008Robert M. Emerson Existing analyses of informal control within dyadic relations neglect the nonpenal responses that characterize many such control efforts, and they give minimal attention to the interactional and interpretive processes that characterize such responses. And while dispute transformation provides a well-developed model of the development of dyadic disputes, this model is limited in prespecifying "injury" as the starting point for these processes and in neglecting informal reactions other than "claiming." Integrating theories of informal control and dispute transformation, this article provides a case study analyzing the nature and processes of informal reactions to troubles involving college roommates, identifying three general categories of such response: managerial reactions, which involve unilateral, nonconfrontational efforts to manage the consequences or implications of the trouble or to change indirectly the troubling behavior; complaint-making reactions, where the troubled party attempts to get the other to change the disturbing behavior; and distancing and punitive reactions, which are relationally despairing responses marked by open confrontation and hostility. [source] A taxonomy of biological informationOIKOS, Issue 2 2010Richard H. Wagner Reproduction, and thus information transfer across generations, is the most essential process of life, yet biologists lack a consensus on terms to define biological information. Unfortunately, multiple definitions of the same terms and other disagreements have long inhibited the development of a general framework for integrating the various categories of biological information. Currently, the only consensus is over two general categories, genetic information, which is encoded in DNA, and non-genetic information, which is extracted from the environment. Non-genetic information is the key to understanding gene-environment interactions and is the raw material of fields such as developmental plasticity, behavior, communication, social learning and cultural evolution. In effect, differences in information possessed by individuals produce phenotypic variation. We thus define biological information as ,factors that can affect the phenotype in ways that may influence fitness'. This definition encompasses all information that is potentially relevant to organisms, which includes the physical environment. Biological information can be acquired passively from genes or via processes such as epigenetics, parental effects and habitat inheritance, or actively by organisms sensing facts about their environment. The confusion over definitions mainly concerns non-genetic information, which takes many more forms than genetic information. Much of the confusion derives from definitions based on how information is used rather than on the facts from which it is extracted. We recognize that a fact becomes information once it is detected. Information can thus be viewed analogously to energy in being either potential or realized. Another source of confusion is in the use of words outside their usual meanings. We therefore present intuitive definitions and classify them according to categories of facts in a hierarchical framework. Clarifying these concepts and terms may help researchers to manipulate facts, allowing a fuller study of biological information. [source] Virtual reality simulators: Current status in acquisition and assessment of surgical skillsANZ JOURNAL OF SURGERY, Issue 1 2002Peter H. Cosman Medical technology is currently evolving so rapidly that its impact cannot be analysed. Robotics and telesurgery loom on the horizon, and the technology used to drive these advances has serendipitous side-effects for the education and training arena. The graphical and haptic interfaces used to provide remote feedback to the operator , by passing control to a computer , may be used to generate simulations of the operative environment that are useful for training candidates in surgical procedures. One additional advantage is that the metrics calculated inherently in the controlling software in order to run the simulation may be used to provide performance feedback to individual trainees and mentors. New interfaces will be required to undergo evaluation of the simulation fidelity before being deemed acceptable. The potential benefits fall into one of two general categories: those benefits related to skill acquisition, and those related to skill assessment. The educational value of the simulation will require assessment, and comparison to currently available methods of training in any given procedure. It is also necessary to determine , by repeated trials , whether a given simulation actually measures the performance parameters it purports to measure. This trains the spotlight on what constitutes good surgical skill, and how it is to be objectively measured. Early results suggest that virtual reality simulators have an important role to play in this aspect of surgical training. [source] UPPER BOUNDS ON THE MINIMUM COVERAGE PROBABILITY OF CONFIDENCE INTERVALS IN REGRESSION AFTER MODEL SELECTIONAUSTRALIAN & NEW ZEALAND JOURNAL OF STATISTICS, Issue 3 2009Paul Kabaila Summary We consider a linear regression model, with the parameter of interest a specified linear combination of the components of the regression parameter vector. We suppose that, as a first step, a data-based model selection (e.g. by preliminary hypothesis tests or minimizing the Akaike information criterion , AIC) is used to select a model. It is common statistical practice to then construct a confidence interval for the parameter of interest, based on the assumption that the selected model had been given to us,a priori. This assumption is false, and it can lead to a confidence interval with poor coverage properties. We provide an easily computed finite-sample upper bound (calculated by repeated numerical evaluation of a double integral) to the minimum coverage probability of this confidence interval. This bound applies for model selection by any of the following methods: minimum AIC, minimum Bayesian information criterion (BIC), maximum adjusted,R2, minimum Mallows' CP and,t -tests. The importance of this upper bound is that it delineates general categories of design matrices and model selection procedures for which this confidence interval has poor coverage properties. This upper bound is shown to be a finite-sample analogue of an earlier large-sample upper bound due to Kabaila and Leeb. [source] Performance of shark teeth during puncture and draw: implications for the mechanics of cuttingBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 2 2010LISA B. WHITENACK The performance of an organism's feeding apparatus has obvious implications for its fitness and survival. However, the majority of studies that focus on chondrichthyan feeding have largely ignored the role of teeth. Studying the functional morphology of shark teeth not only elucidates the biological role that teeth play in feeding, but also provides insight specifically into the evolution of shark feeding because teeth are often the only structures available in the fossil record. In the present study, we investigate the puncture and draw performance of three general categories of extant teeth, tearing-type, cutting-type, and cutting,clutching type, as well as three fossil morphologies, utilizing a universal testing system. Differences in puncturing performance occurred among different prey items, indicating that not all ,soft' prey items are alike. The majority of teeth were able to puncture different prey items, and differences in puncture performance also occurred among tooth types; however, few patterns emerged. In some cases, broader triangular teeth were less effective at puncturing than narrow-cusped teeth. There were no differences between the maximum draw forces and maximum puncture forces. Many of the shark teeth in the present study were not only able to perform draw and puncture equally well, but also many tooth morphologies were functionally equivalent to each other. The findings obtained in the present study lend little support to the belief that shark tooth morphology is a good predictor of biological role. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 271,286. [source] Modulation of aggressive behaviour by fighting experience: mechanisms and contest outcomesBIOLOGICAL REVIEWS, Issue 1 2006Yuying Hsu ABSTRACT Experience in aggressive contests often affects behaviour during, and the outcome of, later contests. This review discusses evidence for, variations in, and consequences of such effects. Generally, prior winning experiences increase, and prior losing experiences decrease, the probability of winning in later contests, reflecting modifications of expected fighting ability. We examine differences in the methodologies used to study experience effects, and the relative importance and persistence of winning and losing experiences within and across taxa. We review the voluminous, but somewhat disconnected, literature on the neuroendocrine mechanisms that mediate experience effects. Most studies focus on only one of a number of possible mechanisms without providing a comprehensive view of how these mechanisms are integrated into overt behaviour. More carefully controlled work on the mechanisms underlying experience effects is needed before firm conclusions can be drawn. Behavioural changes during contests that relate to prior experience fall into two general categories. Losing experiences decrease willingness to engage in a contest while winning experiences increase willingness to escalate a contest. As expected from the sequential assessment model of contest behaviour, experiences become less important to outcomes of contests that escalate to physical fighting. A limited number of studies indicate that integration of multiple experiences can influence current contest behaviour. Details of multiple experience integration for any species are virtually unknown. We propose a simple additive model for this integration of multiple experiences into an individual's expected fighting ability. The model accounts for different magnitudes of experience effects and the possible decline in experience effects over time. Predicting contest outcomes based on prior experiences requires an algorithm that translates experience differences into contest outcomes. We propose two general types of model, one based solely on individual differences in integrated multiple experiences and the other based on the probability contests reach the escalated phase. The difference models include four algorithms reflecting possible decision rules that convert the perceived fighting abilities of two rivals into their probabilities of winning. The second type of algorithm focuses on how experience influences the probability that a subsequent contest will escalate and the fact that escalated contests may not be influenced by prior experience. Neither type of algorithm has been systematically investigated. Finally, we review models for the formation of dominance hierarchies that assume that prior experience influences contest outcome. Numerous models have reached varied conclusions depending on which factors examined in this review are included. We know relatively little about the importance of and variation in experience effects in nature and how they influence the dynamics of aggressive interactions in social groups and random assemblages of individuals. Researchers should be very active in this area in the next decade. The role of experience must be integrated with other influences on contest outcome, such as prior residency, to arrive at a more complete picture of variations in contest outcomes. We expect that this integrated view will be important in understanding other types of interactions between individuals, such as mating and predator-prey interactions, that also are affected significantly by prior experiences. [source] Ethical Challenges in Practice-Based Mental Health Services Research: Examples From Research With Children and FamiliesCLINICAL PSYCHOLOGY: SCIENCE AND PRACTICE, Issue 2 2008Ann F. Garland Researchers have been encouraged to improve the practical relevance and utility of their work by conducting research based on "real-world" service settings and collaborating with other stakeholders, such as service providers and consumers. Practice-based research presents multiple ethical challenges, not well addressed in the literature. We discuss ethical challenges in three general categories, derived from our experience in practice-based research on child and family services: (a) multiple roles and potentially competing demands of research and clinical care, (b) multiple potential uses of research data, and (c) policy and fiscal challenges. Suggested directions for future work are also proposed. [source] Presentation and comments on EU legislation related to food industries,environment interactions: organic contaminants (chemicals, pesticides, dioxins, furans, biocides and their waste management)INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 7 2006Ioannis S. Arvanitoyannis Summary The first part of this review on European Union (EU) legislation related to food industries,environment interactions deals with chemicals which, in their majority, make their way to food. Such substances are the pesticides and fertilizers the residues of which abound in many agricultural produces (both of plant or animal origin). Another crucial issue is the unintentional release of dioxins and furans through combustion. Detergents or sanitizers in conjunction with compounds considered hazardous or corrosive or flammable stand for other topics falling in the general category of chemicals employed in the food industry. The aim of this review is to cover all the current EU legislation in the field of chemicals (dioxins, furans, pesticides, biocides products, fertilizers, sanitizers) coming directly or indirectly in contact with food and their waste management by providing six comprehensive and easy-to-use tables, and a synopsis of the main points of the currently in force EU legislation. [source] | |||||||||||||