387 research outputs found

    Increased seed consumption by biological control weevil tempers positive CO\u3csub\u3e2\u3c/sub\u3e effect on invasive plant (\u3ci\u3eCentaurea diffusa\u3c/i\u3e) fitness

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    Predicted increases in atmospheric CO2 and temperature may benefit some invasive plants, increasing the need for effective invasive plant management. Biological control can be an effective means of managing invasive plants, but the anticipated range in responses of plant–insect interactions to climate change make it difficult to predict how effective biological control will be in the future. Field experiments that manipulate climate within biological control systems could improve predictive power, but are challenging to implement and therefore rare to date. Here, we show that free air CO2 enrichment in the field increased the fitness of Centaurea diffusa Lam., a problematic invader in much of the western United States. However, CO2 enrichment also increased the impact of the biological control agent Larinus minutus (Coleoptera: Curculionidae) on C. diffusa fitness. C. diffusa plants flowered earlier and seed heads developed faster with both elevated CO2 and increased temperature. Natural dispersal of L. minutus into the experimental plots provided a unique opportunity to examine weevil preference for and effects on C. diffusa grown under the different climate change treatments. Elevated CO2 increased both the proportion of seed heads infested by L. minutus and, correspondingly, the amount of seed removed by weevils. Warming had no detectable effect on weevil utilization of plants. Higher weevil densities on elevated CO2 plants reduced, but did not eliminate, the positive effects of CO2 on C. diffusa fitness. Correlations between plant development time and weevil infestation suggest that climate change increased weevil infestation by hastening plant phenology. Phenological mismatches are anticipated with climate change in many plant–insect systems, but in the case of L. minutus and C. diffusa in mixed-grass prairie, a better phenological match may make the biological control agent more effective as CO2 levels rise

    Perceptions of High Integrity Can Persist after Deception: How Implicit Beliefs Moderate Trust Erosion

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    Scholars have assumed that trust is fragile: difficult to build and easily broken. We demonstrate, however, that in some cases trust is surprisingly robust—even when harmful deception is revealed, some individuals maintain high levels of trust in the deceiver. In this paper, we describe how implicit theories moderate the harmful effects of revealed deception on a key component of trust: perceptions of integrity. In a negotiation context, we show that people who hold incremental theories (beliefs that negotiating abilities are malleable) reduce perceptions of their counterpart’s integrity after they learn that they were deceived, whereas people who hold entity theories (beliefs that negotiators’ characteristics and abilities are fixed) maintain their first impressions after learning that they were deceived. Implicit theories influenced how targets interpreted evidence of deception. Individuals with incremental theories encoded revealed deception as an ethical violation; individuals with entity theories did not. These findings highlight the importance of implicit beliefs in understanding how trust changes over time

    Mental Wellbeing:Future Agenda Drawing from Design, HCI and Big Data

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    Most HCI work on the exploration and support of mental wellbeing involves mobiles, sensors, and various on-line systems which focus on tracking users. However, adoption of, and adherence to such systems is not ideal. Are there innovative ways to better design for mental wellbeing? A promising novel approach is to encourage changes to behavior through the use of tailored feedback informed by machine learning algorithms applied to large sets of use data. This one day workshop aims to explore novel ways to actively engage participants through interactive systems, with an overall aim to shape the research agenda of future HCI work on mental wellbeing. The workshop is designed in an innovative format offering a mixture of traditional presentation, hands-on design and future-thinking activities. The workshop brings together both practitioners and HCI researchers from across a range areas addressing mental wellbeing

    Water Availability Dictates How Plant Traits Predict Demographic Rates

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    A major goal in ecology is to make generalizable predictions of organism responses to environmental variation based on their traits. However, straightforward relationships between traits and fitness are rare and likely to vary with environmental context. Characterizing how traits mediate demographic responses to the environment may enhance the predictions of organism responses to global change. We synthesized 15 years of demographic data and species-level traits in a shortgrass steppe to determine whether the effects of leaf and root traits on growth and survival depended on seasonal water availability. We predicted that (1) species with drought-tolerant traits, such as lower leaf turgor loss point (TLP) and higher leaf and root dry matter content (LDMC and RDMC), would be more likely to survive and grow in drier years due to higher wilting resistance, (2) these traits would not predict fitness in wetter years, and (3) traits that more directly measure physiological mechanisms of water use such as TLP would best predict demographic responses. We found that graminoids with more negative TLP and higher LDMC and RDMC had higher survival rates in drier years. Forbs demonstrated similar yet more variable responses. Graminoids grew larger in wetter years, regardless of traits. However, in both wet and dry years, graminoids with more negative TLP and higher LDMC and RDMC grew larger than less negative TLP and low LDMC and RDMC species. Traits significantly mediated the impact of drought on survival, but not growth, suggesting that survival could be a stronger driver of species\u27 drought response in this system. TLP predicted survival in drier years, but easier to measure LDMC and RDMC were equal or better predictors. These results advance our understanding of the mechanisms by which drought drives population dynamics, and show that abiotic context determines how traits drive fitness

    Are you feeling lucky?:lottery-based scheduling for public displays

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    Scheduling content onto pervasive displays is a complex problem. Researchers have identified an array of potential requirements that can influence scheduling decisions, but the relative importance of these different requirements varies across deployments, with context, and over time. In this paper we describe the design and implementation of a lottery-based scheduling approach that allows for the combination of multiple scheduling policies and is easily extensible to accommodate new scheduling requirements

    A social-cognitive approach to understanding gender differences in negotiator ethics: The role of moral identity

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    To date, gender differences in ethics have received little theoretical attention. We utilize a social-cognitive framework to explain why these differences emerge and when women engage in less unethical negotiating behavior than do men. We propose that, relative to men, women’s stronger moral identities suppress unethical negotiating behavior. Study 1 establishes a gender difference in moral identity strength through a meta-analysis of over 19,000 people. Study 2 observes gender differences in two aspects of negotiator ethics – moral disengagement and opportunism. Study 3 establishes moral identity strength as an antecedent to negotiator ethics. Finally, Studies 4 and 5 explore financial incentives as a situational moderator. Because financial incentives temporarily decrease the salience of moral identity, they could mitigate gender differences in negotiator ethics, leading women to act more like men. Across both studies, financial incentives impacted women’s (but not men’s) unethical negotiating behavior. Our findings help to explain why and when gender differences in ethics emerge

    GEO-C:Enabling open cities and the open city toolkit

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    The GEO-C doctoral programme, entitled “Geoinformatics: Enabling Open Cities”, is funded by the EU Marie SkƂodowska-Curie actions (International Training Networks (ITN), European Joint Doctorates) until December 2018, and is managed by three European universities in Germany, Portugal and Spain. 15 doctoral grantholders (Early Stage Researchers) were selected to work on specific three-year projects, all contributing to improving the notion of open cities, and specifically to an Open City Toolkit of methodologies, code, and best practice examples. Contributions include volunteered geographic information (VGI), public information displays, mobility apps to encourage green living, providing open data to immigrant populations, reducing the second-order digital divide, sensing of quality of life, proximity based privacy protection, and spatio-temporal online social media analysis. All doctoral students conducted long-term visits and were embedded in city governments and businesses, to gain experience from multiple perspectives in addition to the researcher and users’ perspective. The projects are situated within three areas: transparency, participation, and collaboration. They took mostly a bottom-up (citizen-centric) approach to (smart) open cities, rather than relying on large IT companies to create smart open cities in a top-down manner. This paper discusses the various contributions to enabling open cities, explains in some detail the Open City Toolkit, and its possible uses and impact on stakeholders. A follow-up doctoral program has been solicited and, if successful, will continue this line of research and will strengthen aspects of privacy, data provenance, and trust, in an effort to improve relations between data (e.g. news) publishers and consumers

    Trading water for carbon in the future : effects of elevated CO2 and warming on leaf hydraulic traits in a semiarid grassland

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    The effects of climate change on plants and ecosystems are mediated by plant hydraulic traits, including interspecific and intraspecific variability of trait phenotypes. Yet, integrative and realistic studies of hydraulic traits and climate change are rare. In a semiarid grassland, we assessed the response of several plant hydraulic traits to elevated CO2 (+200 ppm) and warming (+1.5 to 3°C; day to night). For leaves of five dominant species (three graminoids and two forbs), and in replicated plots exposed to 7 years of elevated CO2, warming, or ambient climate, we measured: stomatal density and size, xylem vessel size, turgor loss point, and water potential (pre-dawn). Interspecific differences in hydraulic traits were larger than intraspecific shifts induced by elevated CO2 and/or warming. Effects of elevated CO2 were greater than effects of warming, and interactions between treatments were weak or not detected. The forbs showed little phenotypic plasticity. The graminoids had leaf water potentials and turgor loss points that were 10% to 50% less negative under elevated CO2; thus, climate change might cause these species to adjust their drought resistance strategy away from tolerance and toward avoidance. The C4 grass also reduced allocation of leaf area to stomata under elevated CO2, which helps explain observations of higher soil moisture. The shifts in hydraulic traits under elevated CO2 were not, however, simply due to higher soil moisture. Integration of our results with others' indicates that common species in this grassland are more likely to adjust stomatal aperture in response to near-term climate change, rather than anatomical traits; this contrasts with apparent effects of changing CO2 on plant anatomy over evolutionary time. Future studies should assess how plant responses to drought may be constrained by the apparent shift from tolerance (via low turgor loss point) to avoidance (via stomatal regulation and/or access to deeper soil moisture)

    Extending the Osmometer Method for Assessing Drought Tolerance in Herbaceous Species

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    Community-scale surveys of plant drought tolerance are essential for understanding semi-arid ecosystems and community responses to climate change. Thus, there is a need for an accurate and rapid methodology for assessing drought tolerance strategies across plant functional types. The osmometer method for predicting leaf osmotic potential at full turgor ((o)), a key metric of leaf-level drought tolerance, has resulted in a 50-fold increase in the measurement speed of this trait; however, the applicability of this method has only been tested in woody species and crops. Here, we assess the osmometer method for use in herbaceous grassland species and test whether (o) is an appropriate plant trait for understanding drought strategies of herbaceous species as well as species distributions along climate gradients. Our model for predicting leaf turgor loss point ((TLP)) from (o) ((TLP)=0.80(o)-0.845) is nearly identical to the model previously presented for woody species. Additionally, (o) was highly correlated with (TLP) for graminoid species ((tlp)=0.944(o)-0.611; r(2)=0.96), a plant functional group previously flagged for having the potential to cause erroneous measurements when using an osmometer. We report that (o), measured with an osmometer, is well correlated with other traits linked to drought tolerance (namely, leaf dry matter content and leaf vulnerability to hydraulic failure) as well as climate extremes linked to water availability. The validation of the osmometer method in an herb-dominated ecosystem paves the way for rapid community-scale surveys of drought tolerance across plant functional groups, which could improve trait-based predictions of ecosystem responses to climate change

    Water Availability Dictates How Plant Traits Predict Demographic Rates

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    A major goal in ecology is to make generalizable predictions of organism responses to environmental variation based on their traits. However, straightforward relationships between traits and fitness are rare and likely to vary with environmental context. Characterizing how traits mediate demographic responses to the environment may enhance the predictions of organism responses to global change. We synthesized 15 years of demographic data and species-level traits in a shortgrass steppe to determine whether the effects of leaf and root traits on growth and survival depended on seasonal water availability. We predicted that (1) species with drought-tolerant traits, such as lower leaf turgor loss point (TLP) and higher leaf and root dry matter content (LDMC and RDMC), would be more likely to survive and grow in drier years due to higher wilting resistance, (2) these traits would not predict fitness in wetter years, and (3) traits that more directly measure physiological mechanisms of water use such as TLP would best predict demographic responses. We found that graminoids with more negative TLP and higher LDMC and RDMC had higher survival rates in drier years. Forbs demonstrated similar yet more variable responses. Graminoids grew larger in wetter years, regardless of traits. However, in both wet and dry years, graminoids with more negative TLP and higher LDMC and RDMC grew larger than less negative TLP and low LDMC and RDMC species. Traits significantly mediated the impact of drought on survival, but not growth, suggesting that survival could be a stronger driver of species\u27 drought response in this system. TLP predicted survival in drier years, but easier to measure LDMC and RDMC were equal or better predictors. These results advance our understanding of the mechanisms by which drought drives population dynamics, and show that abiotic context determines how traits drive fitness
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