1,835 research outputs found

    The Urban Growth Question

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    HYDROGEN PRODUCTION AND DELIVERY INFRASTRUCTURE AS A COMPLEX ADAPTIVE SYSTEM

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    An agent-based model of the transition to a hydrogen transportation economy explores influences on adoption of hydrogen vehicles and fueling infrastructure. Attention is given to whether significant penetration occurs and, if so, to the length of time required for it to occur. Estimates are provided of sensitivity to numerical values of model parameters and to effects of alternative market and policy scenarios. The model is applied to the Los Angeles metropolitan area In the benchmark simulation, the prices of hydrogen and non-hydrogen vehicles are comparable. Due to fuel efficiency, hydrogen vehicles have a fuel savings advantage of 9.8 cents per mile over non-hydrogen vehicles. Hydrogen vehicles account for 60% of new vehicle sales in 20 years from the initial entry of hydrogen vehicles into show rooms, going on to 86% in 40 years and reaching still higher values after that. If the fuel savings is 20.7 cents per mile for a hydrogen vehicle, penetration reaches 86% of new car sales by the 20th year. If the fuel savings is 0.5 cents per mile, market penetration reaches only 10% by the 20th year. To turn to vehicle price difference, if a hydrogen vehicle costs 2,000lessthananonhydrogenvehicle,newcarsalespenetrationreaches922,000 less than a non-hydrogen vehicle, new car sales penetration reaches 92% by the 20th year. If a hydrogen vehicle costs 6,500 more than a non-hydrogen vehicle, market penetration is only 6% by the 20th year. Results from other sensitivity runs are presented. Policies that could affect hydrogen vehicle adoption are investigated. A tax credit for the purchase of a hydrogen vehicle of 2,500taxcreditresultsin882,500 tax credit results in 88% penetration by the 20th year, as compared with 60% in the benchmark case. If the tax credit is 6,000, penetration is 99% by the 20th year. Under a more modest approach, the tax credit would be available only for the first 10 years. Hydrogen sales penetration then reach 69% of sales by the 20th year with the 2,500creditand792,500 credit and 79% with the 6,000 credit. A carbon tax of 38permetrictonisnotlargeenoughtonoticeablyaffectsalespenetration.Ataxof38 per metric ton is not large enough to noticeably affect sales penetration. A tax of 116 per metric ton makes centrally produced hydrogen profitable in the very first year but results in only 64% penetration by year 20 as opposed to the 60% penetration in the benchmark case. Provision of 15 seed stations publicly provided at the beginning of the simulation, in addition to the 15 existing stations in the benchmark case, gives sales penetration rates very close to the benchmark after 20 years, namely, 63% and 59% depending on where they are placed

    The arts, Bohemian scenes, and income

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    Where and how does arts activity drive neighbourhood revitalization? We explore the impact of arts establishments on income in US zip codes, nationally and across quantiles (from four to seven subgroups) of zip codes stratified by disadvantage (based on income and ethnicity/race). We focus on what is new here: how neighbourhood scenes or the mixes of amenities mediate relationships between the arts and income. One dramatic finding is that more bohemian/hip neighbourhoods tend to have less income, contradicting the accounts from Jane Jacobs, Richard Florida and others. Arts and bohemia generate opposing effects, which emerge if we study not a few cases like Greenwich Village, but use more careful measures and larger number of cases. Some arts factors that distinctly influence neighbourhood income include the number of arts establishments; type and range of arts establishments; levels of disadvantage in a neighbourhood; and specific pre­ and co­existing neighbourhood amenities. Rock, gospel and house music appeal to distinct audiences. Our discussion connects this vitalizing role for arts activity to broader community development dynamics. These overall results challenge the view that the arts simply follow, not drive, wealth, and suggest that arts-led strategies can foster neighbourhood revitalization across a variety of income, ethnic, and other contexts

    A no-go for no-go theorems prohibiting cosmic acceleration in extra dimensional models

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    A four-dimensional effective theory that arises as the low-energy limit of some extra-dimensional model is constrained by the higher dimensional Einstein equations. Steinhardt & Wesley use this to show that accelerated expansion in our four large dimensions can only be transient in a large class of Kaluza-Klein models that satisfy the (higher dimensional) null energy condition [1]. We point out that these no-go theorems are based on a rather ad-hoc assumption on the metric, without which no strong statements can be made.Comment: 20 page

    Sensitive sexualities: dichotomized discourse in the erasure of bisexuality

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    A combination of Q methodology and a Think Aloud task explored how cultural knowledge about bisexuality is constructed and maintained. Q methodology revealed positive interpretations of bisexuality. Critical Discourse Analysis of the Think Aloud task however, exposed the maintenance of dualistic categories of sex, gender and sexuality acting as ‘operating systems’ and strategically guiding the social representation of bisexuality as ‘non-existent’, ‘deviant’, ‘abnormal’ and/or ‘promiscuous’. The findings of this study suggest that overt heterosexism is not becoming extinct; instead it has found rather subtle ways of incorporating itself into ‘liberal’ discourses

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+μ+νW^+ \rightarrow \mu^+\nu and WμνW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

    Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at s√=8 TeV with the ATLAS detector

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    The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy s√=8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb−1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30

    Evidence for the Higgs-boson Yukawa coupling to tau leptons with the ATLAS detector

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    Results of a search for H → τ τ decays are presented, based on the full set of proton-proton collision data recorded by the ATLAS experiment at the LHC during 2011 and 2012. The data correspond to integrated luminosities of 4.5 fb−1 and 20.3 fb−1 at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV respectively. All combinations of leptonic (τ → `νν¯ with ` = e, µ) and hadronic (τ → hadrons ν) tau decays are considered. An excess of events over the expected background from other Standard Model processes is found with an observed (expected) significance of 4.5 (3.4) standard deviations. This excess provides evidence for the direct coupling of the recently discovered Higgs boson to fermions. The measured signal strength, normalised to the Standard Model expectation, of µ = 1.43 +0.43 −0.37 is consistent with the predicted Yukawa coupling strength in the Standard Model

    Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector

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    A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13  TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139  fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV
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