90 research outputs found

    Causal explanations - how to generate, identify, and evaluate them

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    The main goal of this dissertation is to provide a solid foundation for a formalization of Inference to the Best Explanation (IBE). This foundation consists of three major components. First, an intuitively adequate and formally precise model of causal explanation. Secondly, an intuitively adequate and formally precise measure of (causal) explanatory power. And third, an intuitively adequate and formally precise criterion of proportionality that is able to identify the most appropriate level of specificity for a causal explanation. While the first component makes it possible to generate and identify causal explanations reliably, the second and third components make it possible to evaluate the strength or quality of causal explanations, which is crucial for identifying the best of a set of competing causal explanations

    Rainfall or Price Variability: What Determines Rangeland Management Decisions? A Simulation-Optimization Approach to South African Savannas

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    Savannas cover the greater part of Africa and Australia and almost half of South America and contribute to the livelihoods of more than 350 million people. With the intensification of land use during the second half of the 20th century, savannas have become increasingly degraded through bush encroachment as a consequence of increased grazing pressure. Research on rangeland dynamics, however, provides contradicting answers with regard to the causes and possible remedies of bush encroachment. In this paper we present results from an application of a simulation-optimization model to the case of extensive rangeland management in South Africa. Our model differs from previous approaches in that it explicitly accounts for the influence of stochastic prices and rainfall on economically optimal management decisions. By showing the implications of neglecting price variation and stochasticity in rangeland models we provide new insights with regard to the determinants of bush encroachment and rangeland managers' economic utility. We demonstrate that, in the case of South Africa, optimal rangeland management is likely to lead to bush encroachment that eventually makes livestock holding unprofitable. Yet, we identify the costs of fire management to be a limiting factor for managers to counteract bush encroachment and explore the impact of policy measures to reduce fire control costs on the ecological and economic sustainability of livestock holding.Equilibrium, bio-economic modeling, grassland management, sustainable strategies, stochastic conditions, Livestock Production/Industries, Q57,

    Can You Help Me with My Pitch? Studying a Tool for Real-Time Automated Feedback

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    Schneider, J., Börner, D., van Rosmalen, P., & Specht, M. (2016). Can You Help Me with My Pitch? Studying a Tool for Real-Time Automated Feedback. IEEE Transactions on Learning Technologies, 9(4), 318-327. doi: 10.1109/TLT.2016.2627043In our pursue to study effective real-time feedback in Technology Enhanced Learning, we developed the Presentation Trainer, a tool designed to support the practice of nonverbal communication skills for public speaking. The tool tracks the user’s voice and body to analyze her performance, and selects the type of real-time feedback to be presented. This paper describes an empirical study where we tested the effects of the Presentation Trainer’s feedback on learners who used the tool while practicing for an elevator-pitch. Results from this study reveal that the feedback has a significant effect on the learners’ motivation, confidence, self-awareness and performance.The underlying research project is partly funded by the METALOGUE project. METALOGUE is a Seventh Framework Programme collaborative project funded by the European Commission, grant agreement number: 611073 (http://www.metalogue.eu)

    Calling on a million minds for community annotation in WikiProteins.

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    WikiProteins enables community annotation in a Wiki-based system. Extracts of major data sources have been fused into an editable environment that links out to the original sources. Data from community edits create automatic copies of the original data. Semantic technology captures concepts co-occurring in one sentence and thus potential factual statements. In addition, indirect associations between concepts have been calculated. We call on a 'million minds' to annotate a 'million concepts' and to collect facts from the literature with the reward of collaborative knowledge discovery. The system is available for beta testing at http://www.wikiprofessional.org.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

    Auxin influx inhibitors 1-NOA, 2-NOA, and CHPAA interfere with membrane dynamics in tobacco cells

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    The phytohormone auxin is transported through the plant body either via vascular pathways or from cell to cell by specialized polar transport machinery. This machinery consists of a balanced system of passive diffusion combined with the activities of auxin influx and efflux carriers. Synthetic auxins that differ in the mechanisms of their transport across the plasma membrane together with polar auxin transport inhibitors have been used in many studies on particular auxin carriers and their role in plant development. However, the exact mechanism of action of auxin efflux and influx inhibitors has not been fully elucidated. In this report, the mechanism of action of the auxin influx inhibitors (1-naphthoxyacetic acid (1-NOA), 2-naphthoxyacetic acid (2-NOA), and 3-chloro-4-hydroxyphenylacetic acid (CHPAA)) is examined by direct measurements of auxin accumulation, cellular phenotypic analysis, as well as by localization studies of Arabidopsis thaliana L. auxin carriers heterologously expressed in Nicotiana tabacum L., cv. Bright Yellow cell suspensions. The mode of action of 1-NOA, 2-NOA, and CHPAA has been shown to be linked with the dynamics of the plasma membrane. The most potent inhibitor, 1-NOA, blocked the activities of both auxin influx and efflux carriers, whereas 2-NOA and CHPAA at the same concentration preferentially inhibited auxin influx. The results suggest that these, previously unknown, activities of putative auxin influx inhibitors regulate overall auxin transport across the plasma membrane depending on the dynamics of particular membrane vesicles

    Molecular mechanisms of cell death: recommendations of the Nomenclature Committee on Cell Death 2018.

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    Over the past decade, the Nomenclature Committee on Cell Death (NCCD) has formulated guidelines for the definition and interpretation of cell death from morphological, biochemical, and functional perspectives. Since the field continues to expand and novel mechanisms that orchestrate multiple cell death pathways are unveiled, we propose an updated classification of cell death subroutines focusing on mechanistic and essential (as opposed to correlative and dispensable) aspects of the process. As we provide molecularly oriented definitions of terms including intrinsic apoptosis, extrinsic apoptosis, mitochondrial permeability transition (MPT)-driven necrosis, necroptosis, ferroptosis, pyroptosis, parthanatos, entotic cell death, NETotic cell death, lysosome-dependent cell death, autophagy-dependent cell death, immunogenic cell death, cellular senescence, and mitotic catastrophe, we discuss the utility of neologisms that refer to highly specialized instances of these processes. The mission of the NCCD is to provide a widely accepted nomenclature on cell death in support of the continued development of the field

    Forest Law enforcement through district blacklisting in the Brazlian Amazon

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    Deforestation in the Brazilian Amazon has dropped substantially after a peak at over 27 thousand square kilometers in 2004. Starting in 2008, the Brazilian Ministry of the Environment has regularly published blacklists of critical districts with high annual forest loss. Farms in blacklisted districts face stricter registration and environmental licensing rules. In this paper, we quantify the impact of blacklisting on deforestation. We first use spatial matching techniques using a large set of covariates to identify appropriate control districts. We then explore the effect of blacklisting on change in deforestation in double difference regression analyses using panel data covering the period from 2002-2012. Several robustness checks are conducted including an analysis of field-based enforcement missions as a potential causal mechanism behind the effectiveness of the blacklist. We find that the blacklist has considerably reduced deforestation in the affected districts even after controlling for in situ enforcement activities
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