1,624 research outputs found

    Reproductive success through high pollinator visitation rates despite self incompatibility in an endangered wallflower

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    PREMISE OF THE STUDY: Self incompatibility (SI) in rare plants presents a unique challenge—SI protects plants from inbreeding depression, but requires a sufficient number of mates and xenogamous pollination. Does SI persist in an endangered polyploid? Is pollinator visitation sufficient to ensure reproductive success? Is there evidence of inbreeding/outbreeding depression? We characterized the mating system, primary pollinators, pollen limitation, and inbreeding/outbreeding depression in Erysimum teretifolium to guide conservation efforts. METHODS: We compared seed production following self pollination and within- and between-population crosses. Pollen tubes were visualized after self pollinations and between-population pollinations. Pollen limitation was tested in the field. Pollinator observations were quantified using digital video. Inbreeding/outbreeding depression was assessed in progeny from self and outcross pollinations at early and later developmental stages. KEY RESULTS: Self-pollination reduced seed set by 6.5× and quadrupled reproductive failure compared with outcross pollination. Pollen tubes of some self pollinations were arrested at the stigmatic surface. Seed-set data indicated strong SI, and fruit-set data suggested partial SI. Pollinator diversity and visitation rates were high, and there was no evidence of pollen limitation. Inbreeding depression (δ) was weak for early developmental stages and strong for later developmental stages, with no evidence of outbreeding depression. CONCLUSIONS: The rare hexaploid E. teretifolium is largely self incompatible and suffers from late-acting inbreeding depression. Reproductive success in natural populations was accomplished through high pollinator visitation rates consistent with a lack of pollen limitation. Future reproductive health for this species will require large population sizes with sufficient mates and a robust pollinator community

    A Feature Analysis Framework for Evaluating Multi-Agent System Development Methodologies

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    This paper proposes a comprehensive and multi-dimensional feature analysis framework for evaluating and comparing methodologies for developing multi-agent systems (MAS). Developed from a synthesis of various existing evaluation frameworks, the novelty of our framework lies in the high degree of its completeness and the relevance of its evaluation criteria. The paper also presents a pioneering effort in identifying the standard steps and concepts to be supported by a MAS-development process and models

    How social role transitions from adolescence to adulthood relate to trajectories of well-being and substance use

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    https://deepblue.lib.umich.edu/bitstream/2027.42/137870/1/occ56.pd

    Grounding knowledge and normative valuation in agent-based action and scientific commitment

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    Philosophical investigation in synthetic biology has focused on the knowledge-seeking questions pursued, the kind of engineering techniques used, and on the ethical impact of the products produced. However, little work has been done to investigate the processes by which these epistemological, metaphysical, and ethical forms of inquiry arise in the course of synthetic biology research. An attempt at this work relying on a particular area of synthetic biology will be the aim of this chapter. I focus on the reengineering of metabolic pathways through the manipulation and construction of small DNA-based devices and systems synthetic biology. Rather than focusing on the engineered products or ethical principles that result, I will investigate the processes by which these arise. As such, the attention will be directed to the activities of practitioners, their manipulation of tools, and the use they make of techniques to construct new metabolic devices. Using a science-in-practice approach, I investigate problems at the intersection of science, philosophy of science, and sociology of science. I consider how practitioners within this area of synthetic biology reconfigure biological understanding and ethical categories through active modelling and manipulation of known functional parts, biological pathways for use in the design of microbial machines to solve problems in medicine, technology, and the environment. We might describe this kind of problem-solving as relying on what Helen Longino referred to as “social cognition” or the type of scientific work done within what Hasok Chang calls “systems of practice”. My aim in this chapter will be to investigate the relationship that holds between systems of practice within metabolic engineering research and social cognition. I will attempt to show how knowledge and normative valuation are generated from this particular network of practitioners. In doing so, I suggest that the social nature of scientific inquiry is ineliminable to both knowledge acquisition and ethical evaluations

    Obliged to calculate: My School, markets, and equipping parents for calculativeness

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    This paper argues neoliberal programs of government in education are equipping parents for calculativeness. Regimes of testing and the publication of these results and other organizational data are contributing to a public economy of numbers that increasingly oblige citizens to calculate. Using the notions of calculative and market devices, this paper examines the Australian Government’s My School website, which publishes academic and organizational information about schools, including national test results. While it is often assumed that such performance technologies contribute to neoliberal reform of education through school choice, the paper argues the website is technically limited in its capacity to facilitate the economic calculations and calculated action of parents resulting in school choice. The paper instead opens My School to analysis as a technique of governmental self-formation. Using the theoretical resources of actor-network theory and Foucauldian scholarship, this paper complicates assumptions in the literature about the extent to which My School actually operates as a ‘market mechanism’. It argues My School attempts to cultivate a calculated form of parental educational agency, irreducible to economic market agency

    Excitation of superconducting qubits from hot non-equilibrium quasiparticles

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    Superconducting qubits probe environmental defects such as non-equilibrium quasiparticles, an important source of decoherence. We show that "hot" non-equilibrium quasiparticles, with energies above the superconducting gap, affect qubits differently from quasiparticles at the gap, implying qubits can probe the dynamic quasiparticle energy distribution. For hot quasiparticles, we predict a non-neligable increase in the qubit excited state probability P_e. By injecting hot quasiparticles into a qubit, we experimentally measure an increase of P_e in semi-quantitative agreement with the model and rule out the typically assumed thermal distribution.Comment: Main paper: 5 pages, 5 figures. Supplement: 1 page, 1 figure, 1 table. Updated to user-prepared accepted version. Key changes: Supplement added, Introduction rewritten, Figs.2,3,5 revised, Fig.4 adde

    Approaches to Treating High Risk and Advanced Renal Cell Carcinoma (RCC): Key Trial Data That Impacts Treatment Decisions in the Clinic

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    Jonathan Chatzkel,1 Mayer Fishman,2 Brian Ramnaraign,1 Padraic O’Malley,3 Guru P Sonpavde4 1Division of Hematology and Oncology, Department of Medicine, University of Florida, Gainesville, FL, USA; 2University of South Florida, Tampa, FL, USA; 3Department of Urology, University of Florida, Gainesville, FL, USA; 4AdventHealth Cancer Institute, Orlando, FL, USACorrespondence: Jonathan Chatzkel, Department of Medicine, University of Florida, Box 100278, Gainesville, Orlando, FL, 32610, USA, Email [email protected]: The treatment paradigm for high risk localized and advanced kidney cancer has been characterized by ongoing changes, with the introduction of vascular endothelial growth factor receptor tyrosine kinase inhibitors (VEGFR TKIs) and later with immune checkpoint blockade. In this article, we review how current evidence informs our decision-making on post-checkpoint inhibitor systemic therapies, the role of adjuvant and/or neoadjuvant therapies, and the role of cytoreductive nephrectomy in the evolving systemic therapy landscape. While some studies support a post-checkpoint inhibitor benefit from the VEGFR TKIs cabozantinib or axitinib, the benefit of doublet therapies including a VEGF receptor inhibitor and a checkpoint inhibitor remains an area of active investigation, with the combination of lenvatinib plus pembrolizumab showing promise but with a Phase III trial of the combination of atezolizumab plus cabozantinib showing no benefit over cabozantinib alone. The role of adjuvant therapy in patients with high-risk disease who have undergone cytoreductive nephrectomy and potentially metastasectomy is also an area of continuing interest. While the S-TRAC study demonstrated a disease-free survival benefit for adjuvant sunitinib, no overall survival benefit was shown, and multiple other studies of adjuvant VEGFR TKI therapy have been negative. Subsequently, adjuvant pembrolizumab has shown a benefit in overall survival, whereas trials of neoadjuvant and adjuvant nivolumab, adjuvant atezolizumab, and adjuvant ipilimumab plus nivolumab have all been negative. Finally, the role for cytoreductive nephrectomy continues to be an area of active debate. The CARMENA study raised important questions about the role of cytoreductive nephrectomy given the advances in VEGFR TKI therapy but was characterized by accrual difficulties and a significant number of patients not receiving treatment according to the study protocol. Two ongoing studies (NORDIC-SUN and PROBE) seek to further address the role of cytoreductive nephrectomy in the doublet therapy era.Keywords: kidney cancer, cytoreductive nephrectomy, immunotherapy, adjuvant therap

    Considering Intra-individual Genetic Heterogeneity to Understand Biodiversity

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    In this chapter, I am concerned with the concept of Intra-individual Genetic Hetereogeneity (IGH) and its potential influence on biodiversity estimates. Definitions of biological individuality are often indirectly dependent on genetic sampling -and vice versa. Genetic sampling typically focuses on a particular locus or set of loci, found in the the mitochondrial, chloroplast or nuclear genome. If ecological function or evolutionary individuality can be defined on the level of multiple divergent genomes, as I shall argue is the case in IGH, our current genetic sampling strategies and analytic approaches may miss out on relevant biodiversity. Now that more and more examples of IGH are available, it is becoming possible to investigate the positive and negative effects of IGH on the functioning and evolution of multicellular individuals more systematically. I consider some examples and argue that studying diversity through the lens of IGH facilitates thinking not in terms of units, but in terms of interactions between biological entities. This, in turn, enables a fresh take on the ecological and evolutionary significance of biological diversity

    Scn1b deletion in adult mice results in seizures and SUDEP

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    Pathogenic lossâ ofâ function variants in SCN1B are linked to Dravet syndrome (DS). Previous work suggested that neuronal pathfinding defects underlie epileptogenesis and SUDEP in the Scn1b null mouse model of DS. We tested this hypothesis by inducing Scn1b deletion in adult mice that had developed normally. Epilepsy and SUDEP, which occur by postnatal day 21 in Scn1b null animals, were observed within 20 days of induced Scn1b deletion in adult mice, suggesting that epileptogenesis in SCN1Bâ DS does not result from defective brain development. Thus, the developmental brain defects observed previously in Scn1b null mice may model other coâ morbidities of DS.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149575/1/acn3785.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149575/2/acn3785_am.pd

    Ecological Invasion, Roughened Fronts, and a Competitor's Extreme Advance: Integrating Stochastic Spatial-Growth Models

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    Both community ecology and conservation biology seek further understanding of factors governing the advance of an invasive species. We model biological invasion as an individual-based, stochastic process on a two-dimensional landscape. An ecologically superior invader and a resident species compete for space preemptively. Our general model includes the basic contact process and a variant of the Eden model as special cases. We employ the concept of a "roughened" front to quantify effects of discreteness and stochasticity on invasion; we emphasize the probability distribution of the front-runner's relative position. That is, we analyze the location of the most advanced invader as the extreme deviation about the front's mean position. We find that a class of models with different assumptions about neighborhood interactions exhibit universal characteristics. That is, key features of the invasion dynamics span a class of models, independently of locally detailed demographic rules. Our results integrate theories of invasive spatial growth and generate novel hypotheses linking habitat or landscape size (length of the invading front) to invasion velocity, and to the relative position of the most advanced invader.Comment: The original publication is available at www.springerlink.com/content/8528v8563r7u2742
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