9,967 research outputs found

    Spatially and Temporally Explicit Energy System Modelling to Support the Transition to a Low Carbon Energy Infrastructure – Case Study for Wind Energy in the UK

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    Renewable energy sources and electricity demand vary with time and space and the energy system is constrained by the location of the current infrastructure in place. The transitioning to a low carbon energy society can be facilitated by combining long term planning of infrastructure with taking spatial and temporal characteristics of the energy system into account. There is a lack of studies addressing this systemic view. We soft-link two models in order to analyse long term investment decisions in generation, transmission and storage capacities and the effects of short-term fluctuation of renewable supply: The national energy system model UKTM (UK TIMES model) and a dispatch model. The modelling approach combines the benefits of two models: an energy system model to analyse decarbonisation pathways and a power dispatch model that can evaluate the technical feasibility of those pathways and the impact of intermittent renewable energy sources on the power market. Results give us the technical feasibility of the UKTM solution from 2010 until 2050. This allows us to determine lower bounds of flexible elements and feeding them back in an iterative process (e.g. storage, demand side control, balancing). We apply the methodology to study the long-term investments of wind infrastructure in the United Kingdom

    Multi-Partner Interactions in Corals in the Face of Climate Change

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    Recent research has explored the possibility that increased sea-surface temperatures and decreasing pH (ocean acidification) contribute to the ongoing decline of coral reef ecosystems. Within corals, a diverse microbiome exerts significant influence on biogeochemical and ecological processes, including food webs, organismal life cycles, and chemical and nutrient cycling. Microbes on coral reefs play a critical role in regulating larval recruitment, bacterial colonization, and pathogen abundance under ambient conditions, ultimately governing the overall resilience of coral reef systems. As a result, microbial processes may be involved in reef ecosystem-level responses to climate change. Developments of new molecular technologies, in addition to multidisciplinary collaborative research on coral reefs, have led to the rapid advancement in our understanding of bacterially mediated reef responses to environmental change. Here we review new discoveries regarding (1) the onset of coral-bacterial associations; (2) the functional roles that bacteria play in healthy corals; and (3) how bacteria influence coral reef response to environmental change, leading to a model describing how reef microbiota direct ecosystem-level response to a changing global climate

    Bacterial Acquisition in Juveniles of Several Broadcast Spawning Coral Species

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    Coral animals harbor diverse microorganisms in their tissues, including archaea, bacteria, viruses, and zooxanthellae. The extent to which coral-bacterial associations are specific and the mechanisms for their maintenance across generations in the environment are unknown. The high diversity of bacteria in adult coral colonies has made it challenging to identify species-specific patterns. Localization of bacteria in gametes and larvae of corals presents an opportunity for determining when bacterial-coral associations are initiated and whether they are dynamic throughout early development. This study focuses on the early onset of bacterial associations in the mass spawning corals Montastraea annularis, M. franksi, M. faveolata, Acropora palmata, A. cervicornis, Diploria strigosa, and A. humilis. The presence of bacteria and timing of bacterial colonization was evaluated in gametes, swimming planulae, and newly settled polyps by fluorescence in situ hybridization (FISH) using general eubacterial probes and laser-scanning confocal microscopy. The coral species investigated in this study do not appear to transmit bacteria via their gametes, and bacteria are not detectable in or on the corals until after settlement and metamorphosis. This study suggests that mass-spawning corals do not acquire, or are not colonized by, detectable numbers of bacteria until after larval settlement and development of the juvenile polyp. This timing lays the groundwork for developing and testing new hypotheses regarding general regulatory mechanisms that control bacterial colonization and infection of corals, and how interactions among bacteria and juvenile polyps influence the structure of bacterial assemblages in corals

    Is there a credibility crisis in strategic management research? Evidence on the reproducibility of study findings

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    Recent studies report an inability to replicate previously published research, leading some to suggest that scientific knowledge is facing a credibility crisis. In this essay, we provide evidence on whether strategic management research may itself be vulnerable to these concerns. We conducted a study whereby we attempted to reproduce the empirical findings of 88 articles appearing in the Strategic Management Journal using data reported in the articles themselves. About 70% of the studies did not disclose enough data to permit independent tests of reproducibility of their findings. Of those that could be retested, almost one-third reported hypotheses as statistically significant which were no longer so and far more significant results were found to be non-significant in the reproductions than in the opposite direction. Collectively, incomplete reporting practices, disclosure errors, and possible opportunism limit the reproducibility of most studies. Until disclosure standards and requirements change to include more complete reporting and facilitate tests of reproducibility, the strategic management field appears vulnerable to a credibility crisis

    Economic benefits of Mt. Cook National Park

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    Market and non-market valued decisions are associated with New Zealand's system of national parks. The use benefits of Mount Cook National Park are not priced by the market mechanism, whereas many of the inputs necessary to operate and maintain the Park are priced. Estimates of the economic benefits are relevant information when deciding upon the allocation of resources to, and within, a system of national parks. In 1984, the consumers' surplus for adult New Zealand visitors was about 2.2million.Anestimateofthenetnationalbenefitsisgivenbytheconsumers′surplusobtainedbyNewZealandvisitors,plusthenetbenefitsassociatedwithforeignvisitors,lessthecostofParkmanagementandlandrental.ThenetbenefitofMountCookNationalPark,asitwasin1984,islikelytobepositive,indicatingthatthebenefitsassociatedwiththecurrentusepatternofresourcesexceedstheiropportunitycosttothenation.However,thisresultcannotbeusedtoestablishtheoptimalityofcurrentexpenditureandmanagement.Approximately170,000adultsvisitedMountCookNationalParkover1984;292.2 million. An estimate of the net national benefits is given by the consumers' surplus obtained by New Zealand visitors, plus the net benefits associated with foreign visitors, less the cost of Park management and land rental. The net benefit of Mount Cook National Park, as it was in 1984, is likely to be positive, indicating that the benefits associated with the current use pattern of resources exceeds their opportunity cost to the nation. However, this result cannot be used to establish the optimality of current expenditure and management. Approximately 170,000 adults visited Mount Cook National Park over 1984; 29% were from New Zealand, 25% were from Australia, 18% were from the United States, and 7% were from Japan. Visitors to the Park spend money in towns and villages in the Mackenzie Basin area. Average adult visitor expenditure in the Mackenzie Basin area is 58. These expenditures give rise to secondary economic benefits and create opportunities for regional development. Visitor expenditures in the Mackenzie Basin area are associated with 13.4millionofadditionalregionaloutput,13.4 million of additional regional output, 6.8 million of additional regional income, and 196 jobs. These effects derive their significance from regional objectives; they are not indicators of the national benefits associated with Mount Cook National Park

    Onset of Phase Synchronization in Neurons Conneted via Chemical Synapses

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    We study the onset of synchronous states in realistic chaotic neurons coupled by mutually inhibitory chemical synapses. For the realistic parameters, namely the synaptic strength and the intrinsic current, this synapse introduces non-coherences in the neuronal dynamics, yet allowing for chaotic phase synchronization in a large range of parameters. As we increase the synaptic strength, the neurons undergo to a periodic state, and no chaotic complete synchronization is found.Comment: to appear in Int. J. Bif. Chao

    Two dimensional lattice Gross--Neveu model with domain-wall fermions

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    We investigate the two dimensional lattice Gross--Neveu model in large flavor number limit using the domain-wall fermion formulation, as a toy model of lattice QCD. We study nonperturbative behaviorn of the restoration of chiral symmetry of the domain-wall fermions as the extent of the extra dimension (Ns)(N_s) is increased to infinity. We find the the parity broken phase (Aoki phase) for finite NsN_s, and study the phase diagram, which is related to the mechanism of the chiral restoration in Ns→∞N_s\to\infty limit. The continuum limit is taken and O(a)O(a) scaling violation of observables vanishes in Ns→∞N_s\to\infty limit. We also examine the systematic dependencies of observables to the parameters.Comment: 36 pages (26 figures), Latex (epsf style-file needed
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