Distribution by Scientific Domains

Kinds of Researchers

  • academic researcher
  • basic researcher
  • clinical researcher
  • consumer researcher
  • education researcher
  • educational researcher
  • empirical researcher
  • entrepreneurship researcher
  • experience researcher
  • family researcher
  • future researcher
  • health researcher
  • independent researcher
  • individual researcher
  • junior researcher
  • management researcher
  • many researcher
  • medical researcher
  • nurse researcher
  • nursing researcher
  • other researcher
  • policy researcher
  • postdoctoral researcher
  • previous researcher
  • public health researcher
  • qualitative researcher
  • several researcher
  • trained researcher
  • young researcher

  • Terms modified by Researchers

  • researcher ability
  • researcher alike
  • researcher award
  • researcher role

  • Selected Abstracts

    Negotiating Multiple Roles in the Field: Dilemmas of Being an Employee/Researcher

    Ashley Spalding
    More North Americanists must consider the implications of combining paid work with research since funding for our projects is not keeping up with the rising number of anthropologists conducting research in North America. In this article, I reflect on my own paid work and dissertation research in a divided "mixed income" neighborhood in Tampa, Florida. I negotiated multiple roles conducting research with both middle-class homeowners and low-income renters while working as an employee in one of the neighborhood's low-income apartment complexes. Paid work has advantages beyond making research financially possible. For instance, it enables greater access and insight into particular issues. It can also complicate a researcher's role/s in numerous ways, including how she is perceived by different members of the communities in which she works, and the practical and ethical issues that result. [source]

    Making the Leap from Researcher to Planner: Lessons from Avian Conservation Planning in the Dominican Republic

    Steven C. Latta
    Published accounts of national, multidisciplinary planning efforts and priority setting for avian conservation are not common. I describe the process and results of a broad-based, grassroots-oriented avian conservation planning workshop held in the Dominican Republic in which we designed a coordinated strategy for avian conservation in the country. The planning process sought to (1) increase communication and cooperation among conservationists; (2) familiarize participants with resources pertinent to avian conservation; (3) encourage the transfer of information between researchers and managers; (4) promote the concepts of long-term avian monitoring, avian conservation plans, and species management plans; and (5) develop a common, multidisciplinary strategy to promote the conservation of birds in the Dominican Republic. The workshop highlighted group discussions among research biologists, managers, educators, and public policy specialists to assess avian conservation needs and priorities with respect to each discipline and has since galvanized a significant portion of the conservation community around several cooperative projects involving diverse segments of the community. Avian biologists can play a significant role in conservation efforts through a willingness to work with key players in diverse fields and to envision holistic, multidisciplinary approaches to conservation issues. Resumen: Cuando los biologícos investigadores incursionan en la biología de la conservación enfrentan nuevos desafíos, especialmente en países extranjeros, al intentar prestar apoyo para esfuerzos de planificación de la conservación. Los informes publicados de esfuerzos de planificación nacional, multidisciplinaria y de establecimiento de prioridades para la conservación de aves no son comunes. Describo el proceso y los resultados de un taller nacional de planificación para conservación de aves en la República Dominicana que utilizaba un proceso fundamental de base amplia donde creamos una estrategia coordinada para la conservación de aves del país. El proceso de planeación buscaba (1) aumentar comunicación y cooperación entre conservacionistas, (2) familiarizar a los participantes con los recursos disponibles para la conservación de aves, (3) estimular la transferencia de información entre investigadores y manejadores, (4) promover los conceptos del monitoreo de aves a largo plazo, planes de conservación de especies y planes de manejo de especies y (5) desarrollar una estrategia multidisciplinaria común para promover la conservación de aves en la República Dominicana. El taller puso a relieve discusiones de grupo entre investigadores, manejadores, educadores y especialistas en política pública para evaluar las necesidaes y prioridades para la conservación de aves con respecto a cada disciplina, desde entonces se ha estimulado a una porción significativa de la comunidad conservacionista alrededor de proyectos de cooperación que involucran a diversos segmentos de la comunidad. Los ornitólogos pueden jugar un papel significativo en los esfuerzos de conservación mediante una buena disposición para trabajar con personas clave en diversas disciplinas y visualizar de una manera integral y multidisciplinaria las estrategias para abordar asuntos de conservación. [source]

    Benefiting from Commissioned Research: The Role of Researcher , Client Cooperation

    Geir Grundvåg Ottesen
    This paper discusses why commissioned research is often neglected and misunderstood, as well as how its use can be enhanced. We argue that the lack of use of such research can be attributed to differences in researchers' and practitioners' knowledge and expectations regarding research problems, solutions, interpretations, and applications. Two hypotheses are proposed, which link the use of research to cooperation between researchers and users during the production of the research, and to assistance in interpreting and applying the research results. The hypotheses were tested on a sample of 65 buyers of 86 research projects in the seafood industry. The reported findings reveal that collaboration fosters research utilisation, but also that close cooperation between the providers and the users of research may substitute assistance in enhancing research utilisation. [source]

    Great northern researchers: discoverers of the earliest Palaeozoic vertebrates

    ACTA ZOOLOGICA, Issue 2009
    Hans-Peter Schultze
    Abstract The lives and works of Dr Elga Mark-Kurik and Dr Valentina Karatajute-Talimaa, Estonian and Lithuanian palaeontologists, respectively, are presented as part of their celebration at the 11th Symposium on Early/Lower Vertebrates at Uppsala. Both graduated from the university of their home town, Tartu and Vilnius, respectively. Elga became a Researcher at the Institute of Geology of the Estonian S.S.R. Academy of Sciences, in Tallinn, whereas Valentina worked for the Institute of Geology, Vilnius. Both were mentored by D. V. Obruchev of Moscow. Elga chose placoderms and psammosteid heterostracans as main research objects. Valentina also began with whole fish, antiarch placoderms, but then chose fish microfossils with W. Gross as mentor and discovered the oldest chondrichthyans. Both work as palaeobiologists understanding the implications of their fossils for functional interpretation and palaeogeography; their main contribution is in biostratigraphy (over 50% of their publications). In 1976 Elga organized the 1st Middle Palaeozoic Fossil Fish Symposium in Tallinn. The co-operation of young eastern and western palaeoichthyologists begun there culminating in the 1990s with the international research effort of the UNESCO-IUGS International Geological Correlation Programmes (328, 406 and 491). [source]


    EDUCATIONAL THEORY, Issue 3 2005
    Pamela A. Moss
    The recent federal interest in advancing "scientifically based research," along with the National Research Council's 2002 report Scientific Research in Education (SRE), have provided space and impetus for a more general dialogue across discourse boundaries within the field of educational research. The goal of this article is to develop and illustrate principles for an educative dialogue across research discourses. I have turned to Gadamer's philosophical hermeneutics and the critical dialogue that surrounds it to seek guidance about how we might better understand one another's perspectives and learn more about ourselves through the encounter. To illustrate these principles, I consider the dialogue between SRE authors and critics that was published in Educational Researcher shortly after the release of the report. I focus in particular on one of the many issues about which misunderstandings seem to arise , the nature, status, and role of generalizations , and point to some instructive challenges that each of the articles seems to raise for the others. Finally, I propose what I argue is a more prudent aspiration for general principles in educational research: developing the principles through which open critique and debate across differences might occur and through which sound decisions about particular programs for research might be made. [source]

    Family Therapy Pioneer, Researcher, and Mentor: Lyman C. Wynne, MD, PhD 1923,2007

    Cleveland G. Shields

    Tagging the tags, Process, observations and analysis of conversations in metatagging at an ASIST interactive poster session

    Jennifer E. Graham
    Results from a 2006 ASIST poster session on tagger's motivations are presented. Researcher's conducted short conversations with conference participants as they viewed the researchers' poster and tagged its contents. Using a content analysis method, researchers' conversations with participants were analyzed. Content analysis revealed six broad themes or "clusters" of interest: 1) General, 2) Observations, 3) Specific Uses/Suggestions, 4) Curricular, 5) Concerns and 6) Opportunities/Potentials. Within those clusters various specific points were ranked by frequency of occurrence. Overall findings indicate the ASIST community is interested in seeing what happens with this phenomenon, but voiced very real concerns about the longevity of tagging, specific uses in scholarly environments, and the effect it will have on annotation, bibliographic, and subject analysis. [source]

    Enhancing Neural Network Traffic Incident-Detection Algorithms Using Wavelets

    A. Samant
    Researchers have presented freeway traffic incident-detection algorithms by combining the adaptive learning capability of neural networks with imprecision modeling capability of fuzzy logic. In this article it is shown that the performance of a fuzzy neural network algorithm can be improved through preprocessing of data using a wavelet-based feature-extraction model. In particular, the discrete wavelet transform (DWT) denoising and feature-extraction model proposed by Samant and Adeli (2000) is combined with the fuzzy neural network approach presented by Hsiao et al. (1994). It is shown that substantial improvement can be achieved using the data filtered by DWT. Use of the wavelet theory to denoise the traffic data increases the incident-detection rate, reduces the false-alarm rate and the incident-detection time, and improves the convergence of the neural network training algorithm substantially. [source]

    A Must-Have Manual for Conservation Managers and Researchers

    Grey Hayes
    No abstract is available for this article. [source]

    The North American Industry Classification System and Its Implications for Accounting Research,

    Jayanthi Krishnan
    Abstract Industry classification is an important component of the methodological infrastructure of accounting research. Researchers have generally used the Standard Industrial Classification (SIC) system for assigning firms to industries. In 1999, the major statistical agencies of Canada, Mexico, and the United States began implementing the North American Industry Classification System (NAICS). The new scheme changes industry classification by introducing production as the basis for grouping firms, creating 358 new industries, extensively rearranging SIC categories, and establishing uniformity across all NAFTA nations. We examine the implications of the change for accounting research. We first assess NAICS's effectiveness in forming industry groups. Following Guenther and Rosman 1994, we use financial ratio variances to measure intra-industry homogeneity and find that NAICS offers some improvement over the SIC system in defining manufacturing, transportation, and service industries. We also evaluate whether NAICS might have an impact on empirical research by reproducing part of Lang and Lundholm's 1996 study of information-transfer and industry effects. Using SIC delineations, they focus on whether industry conditions or the level of competition is the main source of uncertainty resolved by earnings announcements. Across all levels of aggregation, we find inferences are similar using either SIC or NAICS. How-ever, we also observe that the regression coefficients in Lang and Lundholm's model show smaller intra-industry dispersion for NAICS, relative to SIC, definitions. Overall, the results suggest that NAICS definitions lead to more cohesive industries. Because of this, researchers may encounter some differences in using NAICS-industry definitions, rather than SIC, but these will depend on research design and industry composition of the sample. [source]

    Agency Relations within the Family Business System: an exploratory approach

    L.A.A. Van den Berghe
    Researchers use various definitions to describe the family firm. The characteristics of family firms that are stressed in each of these definitions are somehow related to family control. All characteristics together reflect a spectrum of family firm types along one core dimension: family involvement in the firm. However, it is more helpful to distinguish among family firms by using their precise type. Each particular family firm type is characterised by a set of agency relations within and between the family system, ownership system and the business system. This paper is a first attempt to apply the insights from agency theory on a highly simplified (reference) family firm situation where the father is full owner and the daughter manager of the family firm. Agency theory establishes the foundation for the optimal contract conditions between father and daughter. While real life is often characterised by bounded rationality and incomplete information, future research should help identify the "optimal contract" be-tween the family/shareholders and management in various family firm types under these circumstances. [source]

    Local authorities, climate change and small and medium enterprises: identifying effective policy instruments to reduce energy use and carbon emissions

    Jaryn Bradford
    Abstract This paper discusses potential policy options available to local and municipal authorities, to achieve reductions in energy usage and greenhouse gas (GHG) emissions from small and medium-sized enterprises (SMEs). Researchers conducted surveys with 112 SMEs, and the results have been used to disaggregate the category of ,SME' into sub-sectors based on industrial sector, two measurements of employee size and annual turnover. A statistical analysis identifies key characteristics and behaviours of the sub-sectors of firms and discusses the type of policy measure these groups of SMEs would probably respond to. The key results of the research indicate that categories of firms differ in terms of energy use behaviours, internal constraints and attitudes toward possible policy options. The paper presents a ,policy matrix' to represent the most and least likely policy options to achieve energy savings from different categories of SMEs. Copyright © 2007 John Wiley & Sons, Ltd and ERP Environment. [source]

    Local Heroes, Narrative Worlds and the Imagination: The Making of a Moral Curriculum Through Experiential Narratives

    CURRICULUM INQUIRY, Issue 1 2008
    ABSTRACT Concern about the impact of narrative worlds and their heroes offered by the media prompted research on encounters with moral models in experiential, narrative curricula. Researchers tracked the extension of a mandated Language Arts curriculum on "heroes" through the experiential narratives of four local heroes chosen collaboratively by teacher, students and researcher. They also elicited and analyzed responses from students to these narrative presentations in order to explore how students understood the narrative worlds presented to them. Instead of focusing on the personalities of the speakers, the researchers considered the experiential stories, and the moments of narrative encounter they offered, as the sources of immediate moral impact. However, this impact, it is suggested, did not adhere to a particular narrative in an undifferentiated manner. Instead, effects varied according to what a particular student brought to the encounter and how he or she was able to experience it. Material from two students' responses illustrates how they brought their own personal and socio-cultural contexts to the encounter, activating existing dispositions and reinforcing inclinations to behave in certain ways. There was some evidence that the students reconstructed the meaning of events in their lives, were able to interpret their environment in new ways, and constructed visions of possible futures based on this curricular experience. [source]

    Service Management,Academic Issues and Scholarly Reflections from Operations Management Researchers,

    DECISION SCIENCES, Issue 2 2007
    Richard Metters
    ABSTRACT Services are now a larger portion of the economy than manufacturing for every nation on Earth, and services are an overwhelming portion of Western economies. While decision-making research has begun responding to this change, much of the scholarly work still addresses manufacturing issues. Particularly revealing is the field of operations management (OM), in which the proportion of manuscripts dedicated to services has been estimated at 3%, 6%, and 7.5% by various authors. We investigate several possible reasons for the neglect of services in research, including the difficulty in defining services, viewing services as derivative activities, a lack of defined processes, a lack of scale in services, and the effect of variability on service performance. We argue that times have changed, and none of these reasons is valid anymore. We sound the warning that failure to emphasize services in our research and teaching may signal the decline of the discipline. We note the proportion of OM faculty in business schools has shrunk in the past 10 years. Finally, we examine a selection of service research agendas and note several directions for high-impact, innovative research to revitalize the decision sciences. With practitioners joining the call for more research in services, the academic community has an exciting opportunity to embrace services and reshape its future. [source]

    Inhibitors of purine and pyrimidine synthesis: mycophenolate, azathioprine, and leflunomide

    Daniel Mimouni
    The major goal in the treatment of autoimmune blistering diseases has changed from simply keeping the patient alive to suppressing disease while maintaining quality of life and minimizing drug side effects. Researchers and clinicians are constantly seeking steroid-sparing agents that would allow a dose reduction in corticosteroids with no loss of benefit. Purine and pyrimidine base inhibitors are commonly used for this purpose. These drugs act by inhibiting cell division and inducing cell death. The pharmacologic and clinical aspects of azathioprine, mycophenolate mofetil, and leflunomide are discussed in this review. [source]

    A new dimension in combining data?

    ACTA ZOOLOGICA, Issue 1 2010
    The use of morphology, phylogenomic data in metazoan systematics
    Abstract Giribet, G. 2010. A new dimension in combining data? The use of morphology and phylogenomic data in metazoan systematics. ,Acta Zoologica (Stockholm) 91: 11,19 Animal phylogenies have been traditionally inferred by using the character state information derived from the observation of a diverse array of morphological and anatomical features, but the incorporation of molecular data into the toolkit of phylogenetic characters has shifted drastically the way researchers infer phylogenies. A main reason for this is the ease at which molecular data can be obtained, compared to, e.g., traditional histological and microscopical techniques. Researchers now routinely use genomic data for reconstructing relationships among animal phyla (using whole genomes or Expressed Sequence Tags) but the amount of morphological data available to study the same phylogenetic patterns has not grown accordingly. Given the disparity between the amounts of molecular and morphological data, some authors have questioned entire morphological programs. In this review I discuss issues related to the combinability of genomic and morphological data, the informativeness of each set of characters, and conclude with a discussion of how morphology could be made scalable by utilizing new techniques that allow for non-intrusive examination of large amounts of preserved museum specimens. Morphology should therefore remains a strong field in evolutionary and comparative biology, as it continues to provide information for inferring phylogenetic patterns, is an important complement for the patterns derived from the molecular data, and it is the common nexus that allows studying fossil taxa with large data sets of molecular data. [source]

    Models of policy-making and their relevance for drug research

    Abstract Introduction and Aims. Researchers are often frustrated by their inability to influence policy. We describe models of policy-making to provide new insights and a more realistic assessment of research impacts on policy. Design and Methods. We describe five prominent models of policy-making and illustrate them with examples from the alcohol and drugs field, before drawing lessons for researchers. Results. Policy-making is a complex and messy process, with different models describing different elements. We start with the incrementalist model, which highlights small amendments to policy, as occurs in school-based drug education. A technical/rational approach then outlines the key steps in a policy process from identification of problems and their causes, through to examination and choice of response options, and subsequent implementation and evaluation. There is a clear role for research, as we illustrate with the introduction of new medications, but this model largely ignores the dominant political aspects of policy-making. Such political aspects include the influence of interest groups, and we describe models about power and pressure groups, as well as advocacy coalitions, and the challenges they pose for researchers. These are illustrated with reference to the alcohol industry, and interest group conflicts in establishing a Medically Supervised Injecting Centre. Finally, we describe the multiple streams framework, which alerts researchers to ,windows of opportunity', and we show how these were effectively exploited in policy for cannabis law reform in Western Australia. Discussion and Conclusions. Understanding models of policy-making can help researchers maximise the uptake of their work and advance evidence-informed policy.[Ritter A, Bammer G. Models of policy-making and their relevance for drug research. Drug Alcohol Rev 2010] [source]

    Empirical support for a multi-dimensional model of sensations experienced by youth during their initial smoking episodes

    ADDICTION, Issue 10 2010
    Chris G. Richardson
    ABSTRACT Aims To examine the dimensionality of sensations experienced during initial tobacco smoking. Design Cross-sectional survey. Setting Thirteen secondary schools located in British Columbia, Canada. Participants Data from 1187 adolescents who responded ,yes' to the question: ,Have you ever tried cigarette smoking, even one or two puffs?'. Measurements Participants answered questions about their demographic characteristics, tobacco smoking history and sensations experienced during their initial smoking episodes. Findings The sensations appear to represent the following three separate but modestly correlated dimensions: a pleasant dimension defined by feeling good and relaxed; an unpleasant dimension defined by coughing, feeling sick and nervous; and a ,buzz' dimension defined by feeling high and dizzy. The three factors made statistically significant contributions to the prediction of transition to regular smoking (defined as having smoked at least 100 cigarettes in one's life-time) after adjusting for age, sex and age at first puff. Conclusions The results suggest that three relatively distinct physiological systems appear to explain the relationship between initial smoking sensations and probability of becoming a regular smoker. Researchers examining sensations experienced during initial tobacco smoking episodes should consider using a three-dimensional profile of symptoms composed of pleasant, unpleasant and buzz dimensions. [source]

    Coefficient shifts in geographical ecology: an empirical evaluation of spatial and non-spatial regression

    ECOGRAPHY, Issue 2 2009
    L. Mauricio Bini
    A major focus of geographical ecology and macroecology is to understand the causes of spatially structured ecological patterns. However, achieving this understanding can be complicated when using multiple regression, because the relative importance of explanatory variables, as measured by regression coefficients, can shift depending on whether spatially explicit or non-spatial modeling is used. However, the extent to which coefficients may shift and why shifts occur are unclear. Here, we analyze the relationship between environmental predictors and the geographical distribution of species richness, body size, range size and abundance in 97 multi-factorial data sets. Our goal was to compare standardized partial regression coefficients of non-spatial ordinary least squares regressions (i.e. models fitted using ordinary least squares without taking autocorrelation into account; "OLS models" hereafter) and eight spatial methods to evaluate the frequency of coefficient shifts and identify characteristics of data that might predict when shifts are likely. We generated three metrics of coefficient shifts and eight characteristics of the data sets as predictors of shifts. Typical of ecological data, spatial autocorrelation in the residuals of OLS models was found in most data sets. The spatial models varied in the extent to which they minimized residual spatial autocorrelation. Patterns of coefficient shifts also varied among methods and datasets, although the magnitudes of shifts tended to be small in all cases. We were unable to identify strong predictors of shifts, including the levels of autocorrelation in either explanatory variables or model residuals. Thus, changes in coefficients between spatial and non-spatial methods depend on the method used and are largely idiosyncratic, making it difficult to predict when or why shifts occur. We conclude that the ecological importance of regression coefficients cannot be evaluated with confidence irrespective of whether spatially explicit modelling is used or not. Researchers may have little choice but to be more explicit about the uncertainty of models and more cautious in their interpretation. [source]

    Predation by an exotic lizard, Anolis sagrei, alters the ant community structure in betelnut palm plantations in southern Taiwan

    Abstract 1.,Predators can affect prey directly by reducing prey abundance and indirectly by altering behavioural patterns of prey. From previous studies, there is little evidence that ant community structure is affected by vertebrate predation. 2.,Researchers tend to consider the interactions between vertebrate predators and ants to be weak. The present study examined the impact of the exotic invasive lizard, Anolis sagrei, on the ant community structure by manipulating the density of lizards within enclosures. The natural density of A. sagrei in the field was surveyed and used as the stocking density rate in the lizard-present sub-enclosures. 3.,Before the lizard density was manipulated, there was no difference in the ant diversity between sub-enclosures. After the lizard density manipulation, the ant diversity in sub-enclosures with A. sagrei present was significantly different from that of enclosures where the lizards were absent, although the overall ant abundance did not differ significantly. 4.,The ant diversity difference was generated by a significant reduction of the ant species Pheidole fervens in sub-enclosures with A. sagrei present. Such an abundance change might be the result of direct predation by the lizards, or it might be generated by a foraging site shift by this ant. 5.,The results of this study thus demonstrated that the invasion of an exotic vertebrate can significantly alter the community structure of ants, perhaps through the combined direct and indirect effects of lizards on ants. [source]

    Researchers in action: a focus on Australia's north

    Tein McDonald Editor
    No abstract is available for this article. [source]

    Separating the influence of resource ,availability' from resource ,imbalance' on productivity,diversity relationships

    ECOLOGY LETTERS, Issue 6 2009
    Bradley J. Cardinale
    Abstract One of the oldest and richest questions in biology is that of how species diversity is related to the availability of resources that limit the productivity of ecosystems. Researchers from a variety of disciplines have pursued this question from at least three different theoretical perspectives. Species energy theory has argued that the summed quantities of all resources influence species richness by controlling population sizes and the probability of stochastic extinction. Resource ratio theory has argued that the imbalance in the supply of two or more resources, relative to the stoichiometric needs of the competitors, can dictate the strength of competition and, in turn, the diversity of coexisting species. In contrast to these, the field of Biodiversity and Ecosystem Functioning has argued that species diversity acts as an independent variable that controls how efficiently limited resources are utilized and converted into new tissue. Here we propose that all three of these fields give necessary, but not sufficient, conditions to explain productivity,diversity relationships (PDR) in nature. However, when taken collectively, these three paradigms suggest that PDR can be explained by interactions among four distinct, non-interchangeable variables: (i) the overall quantity of limiting resources, (ii) the stoichiometric ratios of different limiting resources, (iii) the summed biomass produced by a group of potential competitors and (iv) the richness of co-occurring species in a local competitive community. We detail a new multivariate hypothesis that outlines one way in which these four variables are directly and indirectly related to one another. We show how the predictions of this model can be fit to patterns of covariation relating the richness and biomass of lake phytoplankton to three biologically essential resources (N, P and light) in a large number of Norwegian lakes. [source]

    Herbivore and pathogen damage on grassland and woodland plants: a test of the herbivore uncertainty principle

    ECOLOGY LETTERS, Issue 4 2002
    Stefan A. Schnitzer
    Researchers can alter the behaviour and ecology of their study organisms by conducting such seemingly benign activities as non-destructive measurements and observations. In plant communities, researcher visitation and measurement of plants may increase herbivore damage in some plant species while decreasing it in others. Simply measuring plants could change their competitive ability by altering the amount of herbivore damage that they suffer. Currently, however, there is only limited empirical evidence to support this `herbivore uncertainty principle' (HUP). We tested the HUP by quantifying the amount of herbivore and pathogen damage in 13 plant species (> 1400 individuals) at four different visitation intensities at Cedar Creek Natural History Area, Minnesota, USA. Altogether, we found very little evidence to support the HUP at any intensity of visitation. Researcher visitation did not alter overall plant herbivore damage or survival and we did not detect a significant visitation effect in any of the 13 species. Pathogen damage also did not significantly vary among visitation treatments, although there was some evidence that high visitation caused slightly higher pathogen damage. Based on our results, we question whether this phenomenon should be considered a `principle' of plant ecology. [source]

    Three Options Are Optimal for Multiple-Choice Items: A Meta-Analysis of 80 Years of Research

    Michael C. Rodriguez
    Multiple-choice items are a mainstay of achievement testing. The need to adequately cover the content domain to certify achievement proficiency by producing meaningful precise scores requires many high-quality items. More 3-option items can be administered than 4- or 5-option items per testing time while improving content coverage, without detrimental effects on psychometric quality of test scores. Researchers have endorsed 3-option items for over 80 years with empirical evidence,the results of which have been synthesized in an effort to unify this endorsement and encourage its adoption. [source]

    Action control of autonomous agents in continuous valued space using RFCN

    Shinichi Shirakawa
    Abstract Researchers on action control of autonomous agents and multiple agents have attracted increasing attention in recent years. The general methods using action control of agents are neural network, genetic programming, and reinforcement learning. In this study, we use neural network for action control of autonomous agents. Our method determines the structure and parameter of neural network in evolution. We proposed Flexibly Connected Neural Network (FCN) previously as a method of constructing arbitrary neural networks with optimized structures and parameters to solve unknown problems. FCN was applied to action control of an autonomous agent and showed experimentally that it is effective for perceptual aliasing problems. All of the experiments of FCN, however, are only in grid space. In this paper, we propose a new method based on FCN which can decide correction action in real and continuous valued space. The proposed method, called Real-valued FCN (RFCN), optimizes input,output functions of each unit, parameters of the input,output functions and speed of each unit. In order to examine its effectiveness, we applied the proposed method to action control of an autonomous agent to solve continuous-valued maze problems. © 2008 Wiley Periodicals, Inc. Electron Comm Jpn, 91(2): 31,39, 2008; Published online in Wiley InterScience ( DOI 10.1002/eej.10032 [source]

    High within-individual variation in total mercury concentration in seabird feathers

    Alexander L. Bond
    Abstract To our knowledge, no rigorous assessment of the variation in mercury concentrations within individual seabirds has been made using multiple body feathers. We analyzed five feathers from individual Arctic terns (Sterna paradisaea Pontoppidan), common terns (Sterna hirundo L.), and Leach's storm-petrels (Oceanodroma leucorhoa Veillot) and found levels of within-individual variability higher than population or time-series variation. Using a randomization procedure, we found a large range of possible mercury concentrations if only one feather per individual had been sampled. Researchers should report within-individual variability in future studies. [source]

    A compound Poisson model for the annual area burned by forest fires in the province of Ontario

    ENVIRONMETRICS, Issue 5 2010
    Justin J. Podur
    Abstract We use the compound Poisson probability distribution to model the annual area burned by forest fires in the Canadian province of Ontario. Models for sums-of-random variables, relevant for modeling aggregate insurance claims and assessing insurance risk are also relevant in modeling aggregate area burned based on sums of sizes of individual fires. Researchers have fit the distribution of fire sizes to the truncated power-law (or Pareto) distribution (Ward et al., 2001) and a four-parameter Weibull distribution (Reed and McKelvey, 2002). Armstrong (1999) fitted a lognormal distribution to annual proportion of area burned by forest fires in a region of Alberta. We derive expressions and moments for aggregate area burned in Ontario using fire data from the Ontario Ministry of Natural Resources (OMNR). We derive expressions for the distribution of area burned for "severe" and "mild" fire weather scenarios and for "intensive suppression" and "no suppression" scenarios (represented by the intensive and extensive fire protection zones of the province). These distributions can be used to perform risk analysis of annual area burned. Copyright © 2009 John Wiley & Sons, Ltd. [source]

    Analysis of particulate matter air pollution using Markov random field models of spatial dependence

    ENVIRONMETRICS, Issue 5-6 2002
    Mark S. Kaiser
    Abstract Researchers are beginning to realize the need to take spatial structure into account when modeling data on air pollutants. We develop several models for particulate matter in an urban region that allow spatial dependence to be represented in different manners over a time period of one year. The models are based on a Markov random field approach, and a conceptualization of observed data as arising from two random processes, a conditionally independent observation process and a spatially dependent latent pollution process. Optimal predictors are developed for both of these processes, and predictions of the observation process are used for model assessment. Copyright © 2002 John Wiley & Sons, Ltd. [source]

    Cross-cultural assessment of eating disorders: psychometric properties of a Spanish version of the Bulimia Test-Revised,

    Mayra N. Berrios-Hernandez
    Abstract The purpose of this study was to examine the psychometric properties of a Spanish version of the Bulimia Test-Revised (BULIT-R). The goal was to test the factor-structure equivalence of the BULIT-R across two samples of college students from two different cultures, Spain and the US. Researchers using exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) have reported different model solutions for the factor-structure of the BULIT-R: a one-factor model, a four-factor model, a five-factor model and a six-factor model. For the two samples, CFA did not support any of the models previously reported in the literature. EFA supported a six- and a four-factor models for the US and Spanish samples, respectively. © 2007 John Wiley & Sons, Ltd and Eating Disorders Association. [source]

    The co-morbidity of eating disorders and anxiety disorders: a review

    Jessica M. Swinbourne
    Abstract Objective To critically review the literature examining the co-morbidity between eating disorders and anxiety disorders. Method A review of the literature on the co-morbidity between anorexia nervosa, bulimia nervosa and eating disorders not otherwise specified and the anxiety disorders of OCD, PTSD, social anxiety, GAD, panic and agoraphobia. Results Of the empirical studies undertaken, it is clear that anxiety disorders are significantly more frequent in subjects with eating disorders than the general community. Researchers have shown that often anxiety disorders pre-date eating disorders, leading to a suggestion that early onset anxiety may predispose individuals to developing an eating disorder. To date however, the research presents strikingly inconsistent findings, thus complicating our understanding of eating disorder and anxiety co-morbidity. Furthermore, despite indications that eating disorder prevalence amongst individuals presenting for anxiety treatment may be high, there is a distinct lack of research in this area. Discussion This review critically examines the available research to date on the co-morbidity of eating disorders and anxiety disorders. Some of the methodological limitations of previous research are presented, in order to highlight the issues which warrant further scientific investigation in this area. Copyright © 2007 John Wiley & Sons, Ltd and Eating Disorders Association. [source]