1,369 research outputs found

    MyoD Synergizes with the E-protein HEB Beta to Induce Myogenic Differentiation

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    The MyoD family of basic helix-loop-helix transcription factors function as heterodimers with members of the E-protein family to induce myogenic gene activation. The E-protein HEB is alternatively spliced to generate alpha and beta isoforms. While the function of these molecules has been studied in other cell types, questions persist regarding the molecular functions of HEB proteins in skeletal muscle. Our data demonstrate that HEB alpha expression remains unchanged in both myoblasts and myotubes, whereas HEB beta is upregulated during the early phases of terminal differentiation. Upon induction of differentiation, a MyoD-HEB beta complex bound the E1 E-box of the myogenin promoter leading to transcriptional activation. Importantly, forced expression of HEB beta with MyoD synergistically lead to precocious myogenin expression in proliferating myoblasts. However, after differentiation, HEB alpha and HEB beta synergized with myogenin, but not MyoD, to activate the myogenin promoter. Specific knockdown of HEB beta by small interfering RNA in myoblasts blocked differentiation and inhibited induction of myogenin transcription. Therefore, HEB alpha and HEB beta play novel and central roles in orchestrating the regulation of myogenic factor activity through myogenic differentiation

    Tail probabilities of St. Petersburg sums, trimmed sums, and their limit

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    We provide exact asymptotics for the tail probabilities P{Sn,r>x}\mathbb{P} \{S_{n,r} > x\} as x→∞x \to \infty, for fix nn, where Sn,rS_{n,r} is the rr-trimmed partial sum of i.i.d. St. Petersburg random variables. In particular, we prove that although the St. Petersburg distribution is only O-subexponential, the subexponential property almost holds. We also determine the exact tail behavior of the rr-trimmed limits.Comment: 24 pages, 2 figure

    A Metric Discrepancy Result With Given Speed

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    It is known that the discrepancy DN{ kx} of the sequence { kx} satisfies NDN{ kx} = O((log N) (log log N) 1 + Δ) a.e. for all Δ> 0 , but not for Δ= 0. For nk= Ξk, Ξ> 1 we have NDN{ nkx} ≩ (ÎŁ Ξ+ Δ) (2 Nlog log N) 1 / 2 a.e. for some 0 0 , but not for Δ 0 , there exists a sequence { nk} of positive integers such that NDN{ nkx} ≩ (ÎŁ + Δ) Κ (N) eventually holds a.e. for Δ> 0 , but not for Δ< 0. We also consider a similar problem on the growth of trigonometric sums. © 2016, AkadĂ©miai KiadĂł, Budapest, Hungary

    Perception of nonnative tonal contrasts by Mandarin-English and English-Mandarin sequential bilinguals

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    This study examined the role of acquisition order and crosslinguistic similarity in influencing transfer at the initial stage of perceptually acquiring a tonal third language (L3). Perception of tones in Yoruba and Thai was tested in adult sequential bilinguals representing three different first (L1) and second language (L2) backgrounds: L1 Mandarin-L2 English (MEBs), L1 English-L2 Mandarin (EMBs), and L1 English-L2 intonational/non-tonal (EIBs). MEBs outperformed EMBs and EIBs in discriminating L3 tonal contrasts in both languages, while EMBs showed a small advantage over EIBs on Yoruba. All groups showed better overall discrimination in Thai than Yoruba, but group differences were more robust in Yoruba. MEBs’ and EMBs’ poor discrimination of certain L3 contrasts was further reflected in the L3 tones being perceived as similar to the same Mandarin tone; however, EIBs, with no knowledge of Mandarin, showed many of the same similarity judgments. These findings thus suggest that L1 tonal experience has a particularly facilitative effect in L3 tone perception, but there is also a facilitative effect of L2 tonal experience. Further, crosslinguistic perceptual similarity between L1/L2 and L3 tones, as well as acoustic similarity between different L3 tones, play a significant role at this early stage of L3 tone acquisition.Published versio

    A new framework to enable equitable outcomes: resilience and nexus approaches combined

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    Managing integrated social-ecological systems to reduce risks to human and environmental well-being remains challenging in light of the rate and extent of undesirable changes that are occurring. Developing frameworks that are sufficiently integrative to guide research to deliver the necessary insights into all key system aspects is an important outstanding task. Among existing approaches, resilience and nexus framings both allow focus on unpacking relationships across scales and levels in a system and emphasize the involvement of different groups in decision making to different extents. They also suffer weaknesses and neither approach puts social justice considerations explicitly at its core. This has important implications for understanding who wins and loses out from different decisions and how social and ecological risks and trade-offs are shared and distributed, temporally and spatially. This paper conceptually integrates resilience and nexus approaches, developing a combined framework and indicating how it could effectively be operationalized in cases from mountain and mangrove social-ecological systems. In doing so, it advances understanding of complex social-ecological systems framings for risk-based decision making beyond that which could be achieved through use of either resilience or nexus approaches alone. Important next steps in testing the framework involve empirical and field operationalization, requiring interdisciplinary, mixed method approache

    Modelling and simulating change in reforesting mountain landscapes using a social-ecological framework

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    Natural reforestation of European mountain landscapes raises major environmental and societal issues. With local stakeholders in the Pyrenees National Park area (France), we studied agricultural landscape colonisation by ash (Fraxinus excelsior) to enlighten its impacts on biodiversity and other landscape functions of importance for the valley socio-economics. The study comprised an integrated assessment of land-use and land-cover change (LUCC) since the 1950s, and a scenario analysis of alternative future policy. We combined knowledge and methods from landscape ecology, land change and agricultural sciences, and a set of coordinated field studies to capture interactions and feedback in the local landscape/land-use system. Our results elicited the hierarchically-nested relationships between social and ecological processes. Agricultural change played a preeminent role in the spatial and temporal patterns of LUCC. Landscape colonisation by ash at the parcel level of organisation was merely controlled by grassland management, and in fact depended on the farmer's land management at the whole-farm level. LUCC patterns at the landscape level depended to a great extent on interactions between farm household behaviours and the spatial arrangement of landholdings within the landscape mosaic. Our results stressed the need to represent the local SES function at a fine scale to adequately capture scenarios of change in landscape functions. These findings orientated our modelling choices in the building an agent-based model for LUCC simulation (SMASH - Spatialized Multi-Agent System of landscape colonization by ASH). We discuss our method and results with reference to topical issues in interdisciplinary research into the sustainability of multifunctional landscapes

    A framework for improving the cross-jurisdictional governance of a marine migratory species

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    Marine migratory species require collaborative decision-making because individuals move across jurisdictional boundaries within and between countries. However, governance of these species is not always harmonized or truly collaborative. We analyzed the Recovery Plan for Marine Turtles in Australia 2017 (the Plan) and three of its subsidiary plans for evidence of collaborative governance using a two part gap analysis and interviews with environmental managers, scientists, and other stakeholders involved in the development of the Plan and in managing marine migratory species in Australia more generally. We applied existing adaptive and collaborative governance frameworks, which focused mainly on the social components of collaborative governance, and identified a need for a new, interdisciplinary framework for the collaborative governance of marine turtles in Australia. We applied our new framework to the Plan and identified that while the biological components of the Plan were well-developed, stakeholder analysis and engagement details were largely missing. We recognize that recovery plans are inevitably silent about certain issues but suggest that plans would benefit from including better guidance on stakeholder engagement and analysis. Our framework is directly relevant to harmonizing the management of marine turtles across jurisdictions in Australia but it could also be applied to managing threats towards other migratory species that inhabit large marine jurisdictions

    The Dynamics of Ecosystems, Biodiversity Management and Social Institutions at High Northern Latitudes

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    Ecosystems at high latitudes are highly dynamic, influenced by a multitude of large-scale disturbances. Due to global change processes these systems may be expected to be particularly vulnerable, affecting the sustained production of renewable wood resources and abundance of plants and animals on which local cultures depend. In this paper, we assess the implications of new understandings of high northern latitude ecosystems and what must be done to manage systems for resilience. We suggest that the focus of land management should shift from recovery from local disturbance to sustaining ecosystem functions in the face of change and disruption. The role of biodiversity as insurance for allowing a system to reorganize and develop during the disturbance and reorganization phases needs to be addressed in management and policy. We emphasize that the current concepts of ecological reserves and protected areas need to be reconsidered to developp dynamic tools for sustainable management of ecosystems in face of change. Characteristics of what may be considered as customary reserves at high latitudes are often consistent with a more dynamic view of reserves. We suggest new directions for addressing biodiversity management in dynamic landscapes at high latitudes, and provide empirical examples of insights from unconventional perspectives that may help improve the potential for sustainable management of biodiversity and the generation of ecosystem services

    Millisecond cryo-trapping by the spitrobot crystal plunger simplifies time-resolved crystallography

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    We introduce the spitrobot, a protein crystal plunger, enabling reaction quenching via cryo-trapping with millisecond time-resolution. Canonical micromesh loops are mounted on an electropneumatic piston, reactions are initiated via the liquid application method (LAMA), and finally intermediate states are cryo-trapped in liquid nitrogen. We demonstrate binding of several ligands in microcrystals of three enzymes, and trapping of reaction intermediates and conformational changes in macroscopic crystals of tryptophan synthase
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