Showing papers by "Carleton University published in 2011"
TL;DR: In this article, a framework for considering compositional heterogeneity (the number and proportions of different cover types) and configurational heterogeneity, the spatial arrangement of cover types, is proposed.
Abstract: Biodiversity in agricultural landscapes can be increased with conversion of some production lands into 'more-natural'- unmanaged or extensively managed - lands. However, it remains unknown to what extent biodiversity can be enhanced by altering landscape pattern without reducing agricultural production. We propose a framework for this problem, considering separately compositional heterogeneity (the number and proportions of different cover types) and configurational heterogeneity (the spatial arrangement of cover types). Cover type classification and mapping is based on species requirements, such as feeding and nesting, resulting in measures of 'functional landscape heterogeneity'. We then identify three important questions: does biodiversity increase with (1) increasing heterogeneity of the more-natural areas, (2) increasing compositional heterogeneity of production cover types and (3) increasing configurational heterogeneity of production cover types? We discuss approaches for addressing these questions. Such studies should have high priority because biodiversity protection globally depends increasingly on maintaining biodiversity in human-dominated landscapes.
1,232 citations
TL;DR: The goal of this article is to summarize new biological monitoring information on perfluorinated compounds (PFCs) in aquatic ecosystems (post-2005) as a followup to the critical review published in 2006.
Abstract: The goal of this article is to summarize new biological monitoring information on perfluorinated compounds (PFCs) in aquatic ecosystems (post-2005) as a followup to our critical review published in 2006. A wider range of geographical locations (e.g., South America, Russia, Antarctica) and habitats (e.g., high-mountain lakes, deep-ocean, and offshore waters) have been investigated in recent years enabling a better understanding of the global distribution of PFCs in aquatic organisms. High concentrations of PFCs continue to be detected in invertebrates, fish, reptiles, and marine mammals worldwide. Perfluorooctane sulfonate (PFOS) is still the predominant PFC detected (mean concentrations up to 1900 ng/g ww) in addition to important concentrations of long-chain perfluoroalkyl carboxylates (PFCAs; sum PFCAs up to 400 ng/g ww). More studies have evaluated the bioaccumulation and biomagnification of these compounds in both freshwater and marine food webs. Several reports have indicated a decrease in PFOS level...
668 citations
TL;DR: In this paper, social science could contribute by drawing lessons from political experience and offering theoretical insights to understand the politics of sustainability transitions, and to understand what works and what does not work is being sorted out in the world of practical politics.
Abstract: Although recent scholarship has contributed to our understanding of sustainability transitions, more needs to be done to grasp the politics of these processes. What works and what does not work is being sorted out in the world of practical politics. But social science could contribute by drawing lessons from political experience and offering theoretical insights.
650 citations
TL;DR: In this article, the authors respond to GLM's criticisms of RNR and conclude that little substance is added by GLM that is not already included in RNR, although proponents of GLM may learn from the popular appeal that GLM, with its positive, strength-based focus, has garnered from clinicians over the past decade.
Abstract: The risk-need-responsivity (RNR) model has been widely regarded as the premier model for guiding offender assessment and treatment. The RNR model underlies some of the most widely used risk-needs offender assessment instruments, and it is the only theoretical model that has been used to interpret the offender treatment literature. Recently, the good lives model (GLM) has been promoted as an alternative and enhancement to RNR. GLM sets itself apart from RNR by its positive, strengths-based, and restorative model of rehabilitation. In addition, GLM hypothesizes that enhancing personal fulfillment will lead naturally to reductions in criminogenic needs, whereas RNR posits the reverse direction. In this article the authors respond to GLM’s criticisms of RNR and conclude that little substance is added by GLM that is not already included in RNR, although proponents of RNR may learn from the popular appeal that GLM, with its positive, strength-based focus, has garnered from clinicians over the past decade.
637 citations
TL;DR: In this article, Nisbet et al. explored associations between nature relatedness and a variety of well-being indicators, and used multiple regression analyses to demonstrate the unique relationship of NR with wellbeing, while controlling for other environmental measures.
Abstract: Nature relatedness (NR) describes the affective, cognitive, and experiential aspects of human–nature relationships (Nisbet in Environ Behav 41: 715–740, 2009). Evidence from three studies suggests that individual differences in NR are associated with differences in well-being. In study 1 (N = 184), we explore associations between NR and a variety of well-being indicators, and use multiple regression analyses to demonstrate the unique relationship of NR with well-being, while controlling for other environmental measures. We replicate well-being correlates with a sample of business people (N = 145) in Study 2. In study 3 (N = 170), we explore the influence of environmental education on NR and well-being, and find that changes in NR mediate the relationship between environmental education and changes in vitality. We discuss the potential for interventions to improve psychological health and promote environmental behaviour.
563 citations
TL;DR: The findings indicate the critical factors that enable citizens to adopt e-Gov at different stages of service maturity, and public administrators and policy-makers have potential implications from the findings of the adoption behavior of e- Gov at different maturity levels.
505 citations
TL;DR: In this article, a search for squarks and gluinos in final states containing jets, missing transverse momentum and no electrons or muons is presented, and the data were recorded by the ATLAS experiment in sqrt(s) = 7 TeV proton-proton collisions at the Large Hadron Collider.
452 citations
TL;DR: The results described in this paper indicate that COI sequencing and the dataset generated are a valuable addition to the currently available oomycete taxonomy resources, and that both COI, the default DNA barcode supported by GenBank, and ITS, the de facto barcode accepted by the oomyCete and mycology community, are acceptable and complementary DNA barcodes to be used for identification of oomy cetes.
Abstract: Oomycete species occupy many different environments and many ecological niches. The genera Phytophthora and Pythium for example, contain many plant pathogens which cause enormous damage to a wide range of plant species. Proper identification to the species level is a critical first step in any investigation of oomycetes, whether it is research driven or compelled by the need for rapid and accurate diagnostics during a pathogen outbreak. The use of DNA for oomycete species identification is well established, but DNA barcoding with cytochrome c oxidase subunit I (COI) is a relatively new approach that has yet to be assessed over a significant sample of oomycete genera. In this study we have sequenced COI, from 1205 isolates representing 23 genera. A comparison to internal transcribed spacer (ITS) sequences from the same isolates showed that COI identification is a practical option; complementary because it uses the mitochondrial genome instead of nuclear DNA. In some cases COI was more discriminative than ITS at the species level. This is in contrast to the large ribosomal subunit, which showed poor species resolution when sequenced from a subset of the isolates used in this study. The results described in this paper indicate that COI sequencing and the dataset generated are a valuable addition to the currently available oomycete taxonomy resources, and that both COI, the default DNA barcode supported by GenBank, and ITS, the de facto barcode accepted by the oomycete and mycology community, are acceptable and complementary DNA barcodes to be used for identification of oomycetes.
448 citations
TL;DR: In this paper, the principal methods available for seasonal storage of solar thermal energy are presented, focusing on residential scale systems, and particularly those currently used in practice which mostly store energy in the form of sensible heat.
Abstract: There is generally agreement among the HVAC (Heating Ventilating and Air Conditioning) community that one of the main issues impeding solar thermal technologies from achieving their full potential for space heating and domestic hot water (DHW) production applications is the development of economically competitive and reliable means for seasonal storage of thermal energy. This is particularly true at high latitude locations, where seasonal variations of solar radiation are significant, and in cold climates, where seasonally varying space heating loads dominate residential energy consumption. This review presents the principal methods available for seasonal storage of solar thermal energy. It concentrates on residential scale systems, and particularly those currently used in practice which mostly store energy in the form of sensible heat. Some newer methods that exhibit promise, like chemical and latent storage, are also briefly discussed and pertinent reviews are referenced.
441 citations
TL;DR: In this paper, the particle multiplicity, its dependence on transverse momentum and pseudorapidity and the relationship between the mean transversal momentum and the charged-particle multiplicity are measured.
Abstract: Measurements are presented from proton-proton collisions at centre-of-mass energies of root s = 0.9, 2.36 and 7 TeV recorded with the ATLAS detector at the LHC. Events were collected using a single-arm minimum-bias trigger. The charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity and the relationship between the mean transverse momentum and charged-particle multiplicity are measured. Measurements in different regions of phase space are shown, providing diffraction-reduced measurements as well as more inclusive ones. The observed distributions are corrected to well-defined phase-space regions, using model-independent corrections. The results are compared to each other and to various Monte Carlo (MC) models, including a new AMBT1 pythia6 tune. In all the kinematic regions considered, the particle multiplicities are higher than predicted by the MC models. The central charged-particle multiplicity per event and unit of pseudorapidity, for tracks with p(T) > 100 MeV, is measured to be 3.483 +/- 0.009 (stat) +/- 0.106 (syst) at root s = 0.9 TeV and 5.630 +/- 0.003 (stat) +/- 0.169 (syst) at root s = 7 TeV.
435 citations
TL;DR: This work attempts to resolve misunderstandings about bet hedging and its relationship with other modes of response to environmental change, identify the challenges inherent to its study, assess the state of existing empirical evidence and appraisals of the adaptive significance of putative bet-hedging traits in nature.
Abstract: Uncertainty is a problem not only in human decision-making, but is a prevalent quality of natural environments and thus requires evolutionary response. Unpredictable natural selection is expected to result in the evolution of bet-hedging strategies, which are adaptations to long-term fluctuating selection. Despite a recent surge of interest in bet hedging, its study remains mired in conceptual and practical difficulties, compounded by confusion over what constitutes evidence for its existence. Here, I attempt to resolve misunderstandings about bet hedging and its relationship with other modes of response to environmental change, identify the challenges inherent to its study and assess the state of existing empirical evidence. The variety and distribution of plausible bet-hedging traits found across 16 phyla in over 100 studies suggest their ubiquity. Thus, bet hedging should be considered a specific mode of response to environmental change. However, the distribution of bet-hedging studies across evidence categories—defined according to potential strength—is heavily skewed towards weaker categories, underscoring the need for direct appraisals of the adaptive significance of putative bet-hedging traits in nature.
Book•
24 Nov 2011TL;DR: In this paper, the authors present the complete fundamentals of multiscale modeling for graduate students and researchers in physics, materials science, chemistry, and engineering, with examples drawn from modern research on the thermodynamic properties of crystalline solids.
Abstract: Material properties emerge from phenomena on scales ranging from Angstroms to millimeters, and only a multiscale treatment can provide a complete understanding. Materials researchers must therefore understand fundamental concepts and techniques from different fields, and these are presented in a comprehensive and integrated fashion for the first time in this book. Incorporating continuum mechanics, quantum mechanics, statistical mechanics, atomistic simulations and multiscale techniques, the book explains many of the key theoretical ideas behind multiscale modeling. Classical topics are blended with new techniques to demonstrate the connections between different fields and highlight current research trends. Example applications drawn from modern research on the thermo-mechanical properties of crystalline solids are used as a unifying focus throughout the text. Together with its companion book, Continuum Mechanics and Thermodynamics (Cambridge University Press, 2011), this work presents the complete fundamentals of materials modeling for graduate students and researchers in physics, materials science, chemistry and engineering.
TL;DR: A unified closed-form expression, applicable to different binary modulation schemes, for the bit error rate of dual-branch selection diversity based systems undergoing independent but not necessarily identically distributed generalized-K fading is derived in terms of the extended generalized bivariate Meijer G-function.
Abstract: Error performance is one of the main performance measures and the derivation of its closed-form expression has proved to be quite involved for certain communication systems operating over composite fading channels. In this letter, a unified closed-form expression, applicable to different binary modulation schemes, for the bit error rate of dual-branch selection diversity based systems undergoing independent but not necessarily identically distributed generalized-K fading is derived in terms of the extended generalized bivariate Meijer G-function.
15 Aug 2011
TL;DR: It is demonstrated that the variations in limb position associated with normal use can have a substantial impact on the robustness of EMG pattern recognition, as illustrated by an in- crease in average classification error.
Abstract: Reported studies on pattern recognition of electromyograms (EMG) for the control of prosthetic devices traditionally focus on classification accuracy of signals recorded in a laboratory. The difference between the constrained nature in which such data are often collected and the unpredictable nature of prosthetic use is an example of the semantic gap between research findings and a viable clinical implementation. In this paper, we demonstrate that the variations in limb position associated with normal use can have a substantial impact on the robustness of EMG pattern recognition, as illustrated by an in- crease in average classification error from 3.8% to 18%. We propose to solve this problem by: 1) collecting EMG data and training the classifier in multiple limb positions and by 2) measuring the limb position with accelerometers. Applying these two methods to data from ten normally limbed subjects, we reduce the average classification error from 18% to 5.7% and 5.0%, respectively. Our study shows how sensor fusion (using EMG and accelerometers) may be an efficient method to mitigate the effect of limb position and improve classification accuracy.
TL;DR: The results suggest that all three types of judgments are largely driven by visual appeal, but that cognitively demanding judgments are processed in a qualitatively different manner thanvisual appeal, and that they rely on somewhat different visual attributes.
Abstract: Extremely high correlations between repeated judgments of visual appeal of homepages shown for 50 milliseconds have been interpreted as evidence for a mere exposure effect [Lindgaard et al. 2006]. Continuing that work, the present research had two objectives. First, it investigated the relationship between judgments differing in cognitive demands. Second, it began to identify specific visual attributes that appear to contribute to different judgments. Three experiments are reported. All used the stimuli and viewing time as before. Using a paradigm known to disrupt processing beyond the stimulus offset, Experiment 1 was designed to ensure that the previous findings could not be attributed to such continued processing. Adopting a within-subject design, Experiment 2 investigated the extent to which judgments differing in cognitive demands (visual appeal, perceived usability, trustworthiness) may be driven by the visual characteristics of a Web page. It also enabled analyses of visual attributes that contributed most to the different judgments. Experiment 3 replicated Experiment 2 but using a between-subject design to ensure that no practice effect could occur. The results suggest that all three types of judgments are largely driven by visual appeal, but that cognitively demanding judgments are processed in a qualitatively different manner than visual appeal, and that they rely on somewhat different visual attributes. A model accounting for the results is provided.
TL;DR: A Newton recursive and a Newton iterative identification algorithms are derived by using the Newton method (Newton-Raphson method) to reduce the sensitivity of the projection algorithm to noise, and to improve convergence rates of the SG algorithm.
27 Apr 2011
TL;DR: The Youth Level of Service/Case Management Inventory (YLS/CMI) as discussed by the authors is an actuarial instrument designed to assist the professional in evaluating risk for violent and nonviolent antisocial behavior in youth.
Abstract: The Youth Level of Service/Case Management Inventory (YLS/CMI) is an actuarial instrument designed to assist the professional in evaluating risk for violent and nonviolent antisocial behavior in youth. It also assists in identifying factors placing the youth at risk and therefore may function as a case planning and management tool. The instrument is widely used in juvenile justice, adolescent mental health, and school settings. The measure is appropriate for use by a wide range of professionals, including psychologists, social workers, probation officers, and child care workers. Analyses of reliability, construct validity, and predictive validity have been based on a wide range of samples including males and females and a variety of ethnic, cultural, and national groups.
TL;DR: It is found that although outdoor walks in nearby nature made participants much happier than indoor walks did, participants made affective forecasting errors, such that they systematically underestimated nature’s hedonic benefit.
Abstract: Modern lifestyles disconnect people from nature, and this may have adverse consequences for the well-being of both humans and the environment. In two experiments, we found that although outdoor walks in nearby nature made participants much happier than indoor walks did, participants made affective forecasting errors, such that they systematically underestimated nature's hedonic benefit. The pleasant moods experienced on outdoor nature walks facilitated a subjective sense of connection with nature, a construct strongly linked with concern for the environment and environmentally sustainable behavior. To the extent that affective forecasts determine choices, our findings suggest that people fail to maximize their time in nearby nature and thus miss opportunities to increase their happiness and relatedness to nature. Our findings suggest a happy path to sustainability, whereby contact with nature fosters individual happiness and environmentally responsible behavior.
European Bioinformatics Institute1, University of Jena2, University of Rostock3, University of Tübingen4, Carleton University5, Ansys6, Virginia Bioinformatics Institute7, University of Manchester8, University of Auckland9, Newcastle University10, ETH Zurich11, University of Vienna12, California Institute of Technology13
TL;DR: Three ontologies created specifically to address the needs of the systems biology community are described, including the Systems Biology Ontology, which provides semantic information about the model components, and the Kinetic Simulation Algorithm Ontology and the Terminology for the Description of Dynamics, which categorizes dynamical features of the simulation results and general systems behavior.
Abstract: The use of computational modeling to describe and analyze biological systems is at the heart of systems biology. Model structures, simulation descriptions and numerical results can be encoded in structured formats, but there is an increasing need to provide an additional semantic layer. Semantic information adds meaning to components of structured descriptions to help identify and interpret them unambiguously. Ontologies are one of the tools frequently used for this purpose. We describe here three ontologies created specifically to address the needs of the systems biology community. The Systems Biology Ontology (SBO) provides semantic information about the model components. The Kinetic Simulation Algorithm Ontology (KiSAO) supplies information about existing algorithms available for the simulation of systems biology models, their characterization and interrelationships. The Terminology for the Description of Dynamics (TEDDY) categorizes dynamical features of the simulation results and general systems behavior. The provision of semantic information extends a model's longevity and facilitates its reuse. It provides useful insight into the biology of modeled processes, and may be used to make informed decisions on subsequent simulation experiments.
TL;DR: Overall, this study concretely determined that aspects of fictional narrative construction knowledge can be learned from interactive book reading.
TL;DR: A multiple model/control-based SMC technique is proposed to reduce the level of parametric uncertainty to reduce observer-controller gains and is evaluated on a 2-DOF robot manipulator to demonstrate the effectiveness of the theoretical development.
Abstract: In the face of large-scale parametric uncertainties, the single-model (SM)-based sliding mode control (SMC) approach demands high gains for the observer, controller, and adaptation to achieve satisfactory tracking performance. The main practical problem of having high-gain-based design is that it amplifies the input and output disturbance as well as excites hidden unmodeled dynamics, causing poor tracking performance. In this paper, a multiple model/control-based SMC technique is proposed to reduce the level of parametric uncertainty to reduce observer-controller gains. To this end, we split uniformly the compact set of unknown parameters into a finite number of smaller compact subsets. Then, we design a candidate SMC corresponding to each of these smaller subsets. The derivative of the Lyapunov function candidate is used as a resetting criterion to identify a candidate model that approximates closely the plant at each instant of time. The key idea is to allow the parameter estimate of conventional adaptive sliding mode control design to be reset into a model that best estimates the plant among a finite set of candidate models. The proposed method is evaluated on a 2-DOF robot manipulator to demonstrate the effectiveness of the theoretical development.
TL;DR: In this article, the properties of passive oxide films that form on carbon steel in saturated calcium hydroxide solution and the effect of chloride on the film properties were studied using X-ray photoelectron spectroscopy.
TL;DR: Findings reveal that exposure to air pollution may perturb the trajectory of cerebral development and result in cognitive deficits during childhood.
TL;DR: A gradient-based algorithm is derived to estimate the parameters of the input-output representation with scarce measurements, and the convergence properties of the parameter estimation and unavailable output estimation are established using the Kronecker lemma and the deterministic version of the martingale convergence theorem.
TL;DR: The SAFE Project represents an opportunity for ecologists across disciplines to participate in a large initiative designed to generate a broad understanding of the ecological impacts of tropical forest modification.
Abstract: Opportunities to conduct large-scale field experiments are rare, but provide a unique opportunity to reveal the complex processes that operate within natural ecosystems. Here, we review the design of existing, large-scale forest fragmentation experiments. Based on this review, we develop a design for the Stability of Altered Forest Ecosystems (SAFE) Project, a new forest fragmentation experiment to be located in the lowland tropical forests of Borneo (Sabah, Malaysia). The SAFE Project represents an advance on existing experiments in that it: (i) allows discrimination of the effects of landscape-level forest cover from patch-level processes; (ii) is designed to facilitate the unification of a wide range of data types on ecological patterns and processes that operate over a wide range of spatial scales; (iii) has greater replication than existing experiments; (iv) incorporates an experimental manipulation of riparian corridors; and (v) embeds the experimentally fragmented landscape within a wider gradient of land-use intensity than do existing projects. The SAFE Project represents an opportunity for ecologists across disciplines to participate in a large initiative designed to generate a broad understanding of the ecological impacts of tropical forest modification.
TL;DR: In this article, measurements of luminosity obtained using the ATLAS detector during early running of the Large Hadron Collider (LHC) at root s = 7 TeV are presented, independently determined using several detectors and multiple algorithms, each having different acceptances, systematic uncertainties and sensitivity to background.
Abstract: Measurements of luminosity obtained using the ATLAS detector during early running of the Large Hadron Collider (LHC) at root s = 7 TeV are presented. The luminosity is independently determined using several detectors and multiple algorithms, each having different acceptances, systematic uncertainties and sensitivity to background. The ratios of the luminosities obtained from these methods are monitored as a function of time and of mu, the average number of inelastic interactions per bunch crossing. Residual time- and mu-dependence between the methods is less than 2% for 0 < mu < 2.5. Absolute luminosity calibrations, performed using beam separation scans, have a common systematic uncertainty of +/- 11%, dominated by the measurement of the LHC beam currents. After calibration, the luminosities obtained from the different methods differ by at most +/- 2%. The visible cross sections measured using the beam scans are compared to predictions obtained with the PYTHIA and PHOJET event generators and the ATLAS detector simulation.
TL;DR: In this article, the authors summarize the trends in 108 peer-reviewed electronic tagging effect studies focused on intracoleomic implantation to determine opportunities for future research, and advocate for rigorous controlled manipulations based on statistical designs that have adequate power, account for inter-individual variation, and include controls and shams, and consider how biotic factors (e.g., sex, age, size) influence tagging outcomes.
Abstract: Early approaches to surgical implantation of electronic tags in fish were often through trial and error, however, in recent years there has been an interest in using scientific research to identify techniques and procedures that improve the outcome of surgical procedures and determine the effects of tagging on individuals. Here we summarize the trends in 108 peer-reviewed electronic tagging effect studies focused on intracoleomic implantation to determine opportunities for future research. To date, almost all of the studies have been conducted in freshwater, typically in laboratory environments, and have focused on biotelemetry devices. The majority of studies have focused on salmonids, cyprinids, ictalurids and centrarchids, with a regional bias towards North America, Europe and Australia. Most studies have focused on determining whether there is a negative effect of tagging relative to control fish, with proportionally fewer that have contrasted different aspects of the surgical procedure (e.g., methods of sterilization, incision location, wound closure material) that could advance the discipline. Many of these studies included routine endpoints such as mortality, growth, healing and tag retention, with fewer addressing sublethal measures such as swimming ability, predator avoidance, physiological costs, or fitness. Continued research is needed to further elevate the practice of electronic tag implantation in fish in order to ensure that the data generated are relevant to untagged conspecifics (i.e., no long-term behavioural or physiological consequences) and the surgical procedure does not impair the health and welfare status of the tagged fish. To that end, we advocate for (1) rigorous controlled manipulations based on statistical designs that have adequate power, account for inter-individual variation, and include controls and shams, (2) studies that transcend the laboratory and the field with more studies in marine waters, (3) incorporation of knowledge and techniques emerging from the medical and veterinary disciplines, (4) addressing all components of the surgical event, (5) comparative studies that evaluate the same surgical techniques on multiple species and in different environments, (6) consideration of how biotic factors (e.g., sex, age, size) influence tagging outcomes, and (7) studies that cover a range of endpoints over ecologically relevant time periods.
TL;DR: In this paper, the authors combine elements from two areas that have explored place image more than any others: tourism destination image (TDI) and product-country image (PCI) in an Integrative Model of Place Image.
Abstract: To advance place image theory, this study combines elements from two areas that have explored place image more than any others: tourism destination image (TDI) and product-country image (PCI). Key constructs from each are measured simultaneously in an Integrative Model of Place Image. The model test uses consumer survey data from South Korea to compare image measures of the United States and Japan using structural equation modeling. The results reveal that cognitive country image has greater influence on product factors than on destination factors, while affective country image has greater influence directly on receptivity than indirectly on beliefs. In addition, consumer beliefs exhibit a strong crossover effect between product beliefs and destination receptivity. Newly tested relationships point to a number of directions for future research in place image and branding, and provide empirical evidence of the need for place marketers to move toward greater integration between product- and tourism-oriented ...
TL;DR: In this article, the authors provide a quantitative and qualitative assessment of articles in major tourism journals in order to enhance our understanding of the tourism experience, with a special emphasis on the management issues associated with delivering these experiences to destination visitors.
Abstract: Purpose – The essence of tourism is the development and delivery of travel and visitation experiences. This paper aims to provide a quantitative and qualitative assessment of articles in major tourism journals in order to enhance our understanding of the tourism experience, with a special emphasis on the management issues associated with delivering these experiences to destination visitors. Design/methodology/approach – Several leading tourism journals were evaluated to identify the articles that focused on tourism experiences. Content analysis was used to determine the quantitative extent of the contributions and the qualitative nature of the articles published in each journal. Findings – Despite growth in the total number of articles published by each major journal, there was no substantial increase in experience-related papers. The findings suggest that, despite its fundamental importance, experience-related research remains under-represented in the tourism literature. Research limitations/implications...
TL;DR: In this article, the effects of a new method of mixture proportioning on the creep and shrinkage characteristics of concrete made with recycled concrete aggregate (RCA) are investigated. And the results show that the amounts of shrinkage in concretes made with coarse RCA, and proportioned by the new method, are comparable to, or even lower than, those in similar concrete made entirely with natural aggregates.
Abstract: Laboratory tests are performed to investigate the effects of a new method of mixture proportioning on the creep and shrinkage characteristics of concrete made with recycled concrete aggregate (RCA). In this method, RCA is treated as a two component composite material consisting of residual mortar and natural aggregate; accordingly, when proportioning the concrete mixture, the relative amount and properties of each component are individually considered. The test variables include the mixture proportioning method, and the aggregate type. The results show that the amounts of creep and shrinkage in concretes made with coarse RCA, and proportioned by the new method, are comparable to, or even lower than, those in similar concretes made entirely with natural aggregates. Furthermore, it is demonstrated that by applying the proposed “residual mortar factor” to the existing ACI and CEB methods for calculating creep or shrinkage of conventional concrete, these methods could be also applied to predict the creep and shrinkage of RCA-concrete.