28,911 research outputs found

    Climbing the Job Ladder: New Evidence of Gender Inequity

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    An explanation for the gender wage gap is that women are less able or less willing to 'climb the job ladder.' However, the empirical evidence on gender differences in job mobility has been mixed. Focusing on a subsample of younger, university-educated workers from an Australian longitudinal survey, we find strong evidence that the dynamics of promotions and employer changes worsen women's labour market position.wage gap, job changes, promotions, gender

    Residential On-Site Carsharing and Off-Street Parking Policy in the San Francisco Bay Area, Research Report 11-28

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    In light of rising motorization, transportation planners have increasingly supported alternatives to the indiscriminate use of the car. Off-street parking policy and carsharing have emerged as credible alternatives for discouraging car ownership. This report explores an initiative that could connect these policy fields and build on their synergy: the provision of on-site carsharing service in residential developments. It evaluates the performance of on-site carsharing programs in the San Francisco Bay Area by interviewing developers, planners, and carsharing service providers. Interviews were conducted in four Bay Area cities that support the provision of carsharing as an alternative to the private automobile. Based on these interviews, this report identifies the principal factors contributing to the success or failure of on-site carsharing: the unbundling status of off-street parking in residential developments; ties to off-street parking standards; financial constraints; and the level of coordination among stakeholders. The interviews revealed that on-site carsharing has been accepted by developers, planners, and service providers, particularly in densely-populated, transit-rich communities. Nevertheless, there appears to be a gap between on-site carsharing programs and off-street parking standards, and between carsharing programs and carsharing business operations. The authors recommend that a few models for establishing carsharing policy be tested: a model designed to serve high-density cities with traditional carsharing; and another designed to serve moderately-dense communities, with new carsharing options (e.g., peer-to-peer). In the case of the latter, trip reduction can be achieved through the promotion of alternative modes along major corridors

    Amenity or Necessity? Street Standards as Parking Policy, Research Report 11-23

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    This paper explores the rationales underlying the use of minimum street width requirements to mandate street parking. A survey of 97 cities reveals that this mandate is not a technical necessity based on safety concerns or an amenity reflecting market demand, two common beliefs held by decision-makers. Many residents are likely unwilling to pay for street parking if it is unbundled from housing. The hidden parking policies should be made transparent and subject to public oversight, the double standard between private and public streets should be eliminated, and parking on residential streets should be optional

    Thermal degradation of polymer blends containing poly(vinyl chloride)

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    The thermal degradation of blends of poly(vinyl chloride) ( PVC ) with poly(vinyl acetate) (PVA), and two ethylene-vinyl acetate copolymers containing 70 weight percent vinyl-acetate (EVA70) and 45 weight percent vinyl acetate (EVA45) were studied by thermogravimetric analysis and direct-pyrolysis mass spectrometry. The PVC, PVA, EVA45 and EVA70 degrade in two-step processes for each polymer. The PVA/PVC , EVA45/PVC and the EVA70/PVC blends do show some inter action during the first step of the degradation process while the respective second steps are unaffected. The acid produced by the degradation of one polymer causes accelerated loss of the other acid in the blend. The extent of the interaction is a function of the miscibility of the blends

    Frequency stabilization of an external-cavity diode laser

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    Using a hybrid optical/electronic technique, an external-cavity diode laser was frequency stabilized with respect to the sub-Doppler spectrum of cesium vapor. Laser linewidths of 65 kHz and frequency stabilities of ±10 kHz were obtained

    Activation of σ28-dependent transcription inEscherichia coliby the cyclic AMP receptor protein requires an unusual promoter organization

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    The Escherichia coli aer regulatory region contains a single promoter that is recognized by RNA polymerase containing the flagellar sigma factor, σ28. Expression from this promoter is dependent on direct activation by the cyclic AMP receptor protein, which binds to a target centred 49.5 base pairs upstream from the transcript start. Activator-dependent transcription from the aer promoter was reconstituted in vitro, and a tethered inorganic nuclease was used to find the position of the C-terminal domains of the RNA polymerase α subunits in transcriptionally competent open complexes. We report that the ternary activator-RNA polymerase-aer promoter open complex is organized differently from complexes at previously characterized promoters. Among other E. coli promoters recognized by RNA polymerase containing σ28, only the trg promoter is activated directly by the cyclic AMP receptor protein. The organization of the different promoter elements and the activator binding site at the trg promoter is the same as at the aer promoter, suggesting a common activation mechanism

    Pulverized coal combustion: NOx formation mechanisms under fuel rich and staged combustion conditions

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    Journal ArticleA 2 Kg/h pulverized fuel one dimensional flame combustor was used to determine time resolved NO profiles under fuel rich and staged combustion conditions. Seven solid fuels, including two coal chars, were investigated. Results show that at all fuel rich conditions NO is formed rapidly and then is slowly destroyed

    The Physics Case for the New Muon (g-2) Experiment

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    This White Paper briefly reviews the present status of the muon (g-2) experiment and the physics motivation for a new effort. The present comparison between experiment and theory indicates a tantalizing 3.4σ3.4 \sigma deviation. An improvement in precision on this comparison by a factor of 2--with the central value remaining unchanged--will exceed the ``discovery'' threshold, with a sensitivity above 6σ6 \sigma. The 2.5-fold reduction improvement goal of the new Brookhaven E969 experiment, along with continued steady reduction of the standard model theory uncertainty, will achieve this more definitive test. Already, the (g-2) result is arguably the most compelling indicator of physics beyond the standard model and, at the very least, it represents a major constraint for speculative new theories such as supersymmetry or extra dimensions. In this report, we summarize the present experimental status and provide an up-to-date accounting of the standard model theory, including the expectations for improvement in the hadronic contributions, which dominate the overall uncertainty. Our primary focus is on the physics case that motivates improved experimental and theoretical efforts. Accordingly, we give examples of specific new-physics implications in the context of direct searches at the LHC as well as general arguments about the role of an improved (g-2) measurement. A brief summary of the plans for an upgraded effort complete the report.Comment: 18 pages, 7 figure

    Spin-Dependent Quantum Emission in Hexagonal Boron Nitride at Room Temperature

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    Optically addressable spins associated with defects in wide-bandgap semiconductors are versatile platforms for quantum information processing and nanoscale sensing, where spin-dependent inter-system crossing (ISC) transitions facilitate optical spin initialization and readout. Recently, the van der Waals material hexagonal boron nitride (h-BN) has emerged as a robust host for quantum emitters (QEs), but spin-related effects have yet to be observed. Here, we report room-temperature observations of strongly anisotropic photoluminescence (PL) patterns as a function of applied magnetic field for select QEs in h-BN. Field-dependent variations in the steady-state PL and photon emission statistics are consistent with an electronic model featuring a spin-dependent ISC between triplet and singlet manifolds, indicating that optically-addressable spin defects are present in h-BN - a versatile two-dimensional material promising efficient photon extraction, atom-scale engineering, and the realization of spin-based quantum technologies using van der Waals heterostructures.Comment: 38 pages, 34 figure
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