633 research outputs found

    Ferroelectric and dielectric characterization studies on relaxor- and ferroelectric-like strontium-barium niobates

    Full text link
    Ferroelectric domain structure evolution induced by an external electric field was investigated by means of nematic liquid crystal (NLC) method in two strontium-barium niobate single crystals of nominal composition: Sr_{0.70}Ba_{0.30}Nb_{2}O_{6} (SBN:70 - relaxor) and Sr_{0.26}Ba_{0.74}Nb_{2}O_{6} (SBN:26 - ferroelectric). Our results provide evidence that the broad phase transition and frequency dispersion that are exhibited in SBN:70 crystal have a strong link to the configuration of ferroelectric microdomains. The large leakage current revealed in SBN:26 may compensate internal charges acting as pinning centers for domain walls, which gives rise to a less restricted domain growth similar to that observed in classical ferroelectrics. Microscale studies of a switching process in conjunction with electrical measurements allowed us to establish a relationship between local properties of the domain dynamics and macroscopic response i.e., polarization hysteresis loop and dielectric properties.Comment: 10 pages, 7 figure

    Fredkin Gates for Finite-valued Reversible and Conservative Logics

    Full text link
    The basic principles and results of Conservative Logic introduced by Fredkin and Toffoli on the basis of a seminal paper of Landauer are extended to d-valued logics, with a special attention to three-valued logics. Different approaches to d-valued logics are examined in order to determine some possible universal sets of logic primitives. In particular, we consider the typical connectives of Lukasiewicz and Godel logics, as well as Chang's MV-algebras. As a result, some possible three-valued and d-valued universal gates are described which realize a functionally complete set of fundamental connectives.Comment: 57 pages, 10 figures, 16 tables, 2 diagram

    KNOW How to Make Up Your Mind! Adversarially Detecting and Alleviating Inconsistencies in Natural Language Explanations

    Get PDF
    While recent works have been considerably improving the quality of the natural language explanations (NLEs) generated by a model to justify its predictions, there is very limited research in detecting and alleviating inconsistencies among generated NLEs. In this work, we leverage external knowledge bases to significantly improve on an existing adversarial attack for detecting inconsistent NLEs. We apply our attack to high-performing NLE models and show that models with higher NLE quality do not necessarily generate fewer inconsistencies. Moreover, we propose an off-the-shelf mitigation method to alleviate inconsistencies by grounding the model into external background knowledge. Our method decreases the inconsistencies of previous high-performing NLE models as detected by our attack

    “Stickier” learning through gameplay: an effective approach to climate change education

    Get PDF
    As the impacts of climate change grow, we need better ways to raise awareness and motivate action. Here we assess the effectiveness of an Arctic climate change card game in comparison with the more conventional approach of reading an illustrated article. In-person assessments with control/reading and treatment/game groups (N = 41), were followed four weeks later with a survey. The game was found to be as effective as the article in teaching content of the impacts of climate change over the short term, and was more effective than the article in long-term retention of new information. Game players also had higher levels of engagement and perceptions that they knew ways to help protect Arctic ecosystems. They were also more likely to recommend the game to friends or family than those in the control group were likely to recommend the article to friends or family. As we consider ways to broaden engagement with climate change, we should include games in our portfolio of approaches

    Comparative genomics of <em>Fusarium oxysporum</em> f. sp. <em>melonis</em> reveals the secreted protein recognized by the <em>Fom-2</em> resistance gene in melon

    Get PDF
    Development of resistant crops is the most effective way to control plant diseases to safeguard food and feed production. Disease resistance is commonly based on resistance genes, which generally mediate the recognition of small proteins secreted by invading pathogens. These proteins secreted by pathogens are called 'avirulence' proteins. Their identification is important for being able to assess the usefulness and durability of resistance genes in agricultural settings. We have used genome sequencing of a set of strains of the melon wilt fungus Fusarium oxysporum f. sp. melonis (Fom), bioinformatics-based genome comparison and genetic transformation of the fungus to identify AVRFOM2, the gene that encodes the avirulence protein recognized by the melon Fom-2 gene. Both an unbiased and a candidate gene approach identified a single candidate for the AVRFOM2 gene. Genetic complementation of AVRFOM2 in three different race 2 isolates resulted in resistance of Fom-2-harbouring melon cultivars. AvrFom2 is a small, secreted protein with two cysteine residues and weak similarity to secreted proteins of other fungi. The identification of AVRFOM2 will not only be helpful to select melon cultivars to avoid melon Fusarium wilt, but also to monitor how quickly a Fom population can adapt to deployment of Fom-2-containing cultivars in the field

    Tapping Fresh Currents: Fostering Early-Career Researchers in Transdisciplinary Water Governance Research

    Get PDF
    Water governance is an important, yet complex and contested field. A central challenge for researchers is to engage with multiple understandings and perspectives that can shape water governance, and to move towards more transdisciplinary approaches. These challenges are magnified for early-career researchers (ECRs), and while the need for transdisciplinary approaches and better support for ECRs is increasingly recognised, there remains a lack of understanding of how to achieve this within the wider research community. Thus, this paper investigates through an auto-ethnographic inquiry the practical experiences and challenges faced by a diverse group of ECRs engaging in water governance research. Reflecting on our own endeavours and relevant literature, we identify a range of path-finding experiences and challenges, and explore strategies employed by ECRs to navigate the &#039;uncharted waters&#039; of evolving career pathways in water governance research. &#039;Communities of Practice&#039; are identified as a promising opportunity to support ECRs by enhancing opportunities for reflection and learning. Overall, we argue that there is significant merit in enhancing the way in which water governance research is understood, and improving the means by which ECRs are supported to build capability and contribute in this field

    Tapping fresh currents: fostering early-career researchers in transdisciplinary water governance research

    Get PDF
    Article published in Water AlternativesWater governance is an important, yet complex and contested field. A central challenge for researchers is to engage with multiple understandings and perspectives that can shape water governance, and to move towards more transdisciplinary approaches. These challenges are magnified for early-career researchers (ECRs), and while the need for transdisciplinary approaches and better support for ECRs is increasingly recognised, there remains a lack of understanding of how to achieve this within the wider research community. Thus, this paper investigates through an auto-ethnographic inquiry the practical experiences and challenges faced by a diverse group of ECRs engaging in water governance research. Reflecting on our own endeavours and relevant literature, we identify a range of path-finding experiences and challenges, and explore strategies employed by ECRs to navigate the 'uncharted waters' of evolving career pathways in water governance research. 'Communities of Practice' are identified as a promising opportunity to support ECRs by enhancing opportunities for reflection and learning. Overall, we argue that there is significant merit in enhancing the way in which water governance research is understood, and improving the means by which ECRs are supported to build capability and contribute in this field.Water governance is an important, yet complex and contested field. A central challenge for researchers is to engage with multiple understandings and perspectives that can shape water governance, and to move towards more transdisciplinary approaches. These challenges are magnified for early-career researchers (ECRs), and while the need for transdisciplinary approaches and better support for ECRs is increasingly recognised, there remains a lack of understanding of how to achieve this within the wider research community. Thus, this paper investigates through an auto-ethnographic inquiry the practical experiences and challenges faced by a diverse group of ECRs engaging in water governance research. Reflecting on our own endeavours and relevant literature, we identify a range of path-finding experiences and challenges, and explore strategies employed by ECRs to navigate the 'uncharted waters' of evolving career pathways in water governance research. 'Communities of Practice' are identified as a promising opportunity to support ECRs by enhancing opportunities for reflection and learning. Overall, we argue that there is significant merit in enhancing the way in which water governance research is understood, and improving the means by which ECRs are supported to build capability and contribute in this field.http://www.water-alternatives.org/index.php/alldoc/articles/vol6/v6issue2/217-a6-2-14/fil

    G-protein betagamma-complex is crucial for efficient signal amplification in vision

    Get PDF
    A fundamental question of cell signaling biology is how faint external signals produce robust physiological responses. One universal mechanism relies on signal amplification via intracellular cascades mediated by heterotrimeric G-proteins. This high amplification system allows retinal rod photoreceptors to detect single photons of light. While much is now known about the role of the α-subunit of the rod-specific G-protein transducin in phototransduction, the physiological function of the auxiliary βγ-complex in this process remains a mystery. Here we show that elimination of the transducin γ-subunit drastically reduces signal amplification in intact mouse rods. The consequence is a striking decline in rod visual sensitivity and severe impairment of nocturnal vision. Our findings demonstrate that transducin βγ-complex controls signal amplification of the rod phototransduction cascade and is critical for the ability of rod photoreceptors to function in low light conditions

    Effect of the boundary layer upon the flow in a conical hypersonic nozzle

    Full text link
    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76641/1/AIAA-2269-288.pd
    corecore