16,796 research outputs found

    Uncertainties for Pre- and Post-Launch Radiometric Calibration of Imaging Spectrometers for Multi-Sensor Applications

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    An important aspect to using imaging spectrometer data is the radiometric characterization and calibration of the sensors and validation of their data products and doing so with error budgets with known traceability. The radiometric accuracy of a given sensor is important for demonstrating the expected quality of data from the sensor. Known traceability allows data from multiple sensors to be directly comparable as will become more important in the near future with the expected launches of multiple imaging spectrometers from multiple countries, agencies, and commercial entities. The current work describes the state of pre- and post-launch radiometric absolute and relative uncertainties and their role in harmonising on-orbit data. Examples of prelaunch uncertainties based on the calibration of EnMAP and the calibration planned for the CLARREO Pathfinder Mission are presented highlighting recent work in the area of detector-based approaches using tunable laser sources. Post-launch calibration approaches for Pathfinder, EnMAP, CHIME, and DESIS including traditional vicarious calibration methods and the challenges of working with commercial data are presented. The vicarious calibration discussion relies on the example of the recently-available RadCalNet data to describe typical methods and challenges that will be faced when harmonising data between imaging spectrometers as well as with multispectral sensors

    Stability of Horava-Lifshitz Black Holes in the Context of AdS/CFT

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    The anti--de Sitter/conformal field theory (AdS/CFT) correspondence is a powerful tool that promises to provide new insights toward a full understanding of field theories under extreme conditions, including but not limited to quark-gluon plasma, Fermi liquid and superconductor. In many such applications, one typically models the field theory with asymptotically AdS black holes. These black holes are subjected to stringy effects that might render them unstable. Ho\v{r}ava-Lifshitz gravity, in which space and time undergo different transformations, has attracted attentions due to its power-counting renormalizability. In terms of AdS/CFT correspondence, Ho\v{r}ava-Lifshitz black holes might be useful to model holographic superconductors with Lifshitz scaling symmetry. It is thus interesting to study the stringy stability of Ho\v{r}ava-Lifshitz black holes in the context of AdS/CFT. We find that uncharged topological black holes in λ=1\lambda=1 Ho\v{r}ava-Lifshitz theory are nonperturbatively stable, unlike their counterparts in Einstein gravity, with the possible exceptions of negatively curved black holes with detailed balance parameter ϵ\epsilon close to unity. Sufficiently charged flat black holes for ϵ\epsilon close to unity, and sufficiently charged positively curved black holes with ϵ\epsilon close to zero, are also unstable. The implication to the Ho\v{r}ava-Lifshitz holographic superconductor is discussed.Comment: 15 pages, 6 figures. Updated version accepted by Phys. Rev. D, with corrections to various misprints. References update

    Expectation adjustment in the housing market: insights from the Scottish auction system

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    This paper examines price expectation adjustment of house buyers and sellers to rapid changes in the housing market using data from Scotland where houses are sold through 'first-price sealed-bid' auctions. These auctions provide more information on market signals, incentives and the behaviour of market participants than private treaty sales. This paper therefore provides a theoretical framework for analysing revealed preference data generated from these auctions. We specifically focus on the analysis of the selling to asking price difference, the 'bid-premium'. The bid-premium is shown to be affected by expectations of future price movements, market duration and high bidding frequency. The bid-premium reflects consumers' expectations, adapting to market conditions more promptly than asking price setting behaviour and final sale prices. The volatile conditions of the recent housing market bubble are fully reflected in the bid-premium, whereas the asking and sale prices are much less prone to rapid movements

    Integrin α2β1 Expression Regulates Matrix Metalloproteinase-1-Dependent Bronchial Epithelial Repair in Pulmonary Tuberculosis.

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    Pulmonary tuberculosis (TB) is caused by inhalation of Mycobacterium tuberculosis, which damages the bronchial epithelial barrier to establish local infection. Matrix metalloproteinase-1 plays a crucial role in the immunopathology of TB, causing breakdown of type I collagen and cavitation, but this collagenase is also potentially involved in bronchial epithelial repair. We hypothesized that the extracellular matrix (ECM) modulates M. tuberculosis-driven matrix metalloproteinase-1 expression by human bronchial epithelial cells (HBECs), regulating respiratory epithelial cell migration and repair. Medium from monocytes stimulated with M. tuberculosis induced collagenase activity in bronchial epithelial cells, which was reduced by ~87% when cells were cultured on a type I collagen matrix. Matrix metalloproteinase-1 had a focal localization, which is consistent with cell migration, and overall secretion decreased by 32% on type I collagen. There were no associated changes in the specific tissue inhibitors of metalloproteinases. Decreased matrix metalloproteinase-1 secretion was due to ligand-binding to the α2β1 integrin and was dependent on the actin cytoskeleton. In lung biopsies, samples from patients with pulmonary TB, integrin α2β1 is highly expressed on the bronchial epithelium. Areas of lung with disrupted collagen matrix showed an increase in matrix metalloproteinases-1 expression compared with areas where collagen was comparable to control lung. Type I collagen matrix increased respiratory epithelial cell migration in a wound-healing assay, and this too was matrix metalloproteinase-dependent, since it was blocked by the matrix metalloproteinase inhibitor GM6001. In summary, we report a novel mechanism by which α2β1-mediated signals from the ECM modulate matrix metalloproteinase-1 secretion by HBECs, regulating their migration and epithelial repair in TB

    The Lorenz number in CeCoIn5_5 inferred from the thermal and charge Hall currents

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    The thermal Hall conductivity κxy\kappa_{xy} and Hall conductivity σxy\sigma_{xy} in CeCoIn5_5 are used to determine the Lorenz number LH{\cal L}_H at low temperature TT. This enables the separation of the observed thermal conductivity into its electronic and non-electronic parts. We uncover evidence for a charge-neutral, field-dependent thermal conductivity, which we identify with spin excitations. At low TT, these excitations dominate the scattering of charge carriers. We show that suppression of the spin excitations in high fields leads to a steep enhancement of the electron mean-free-path, which leads to an interesting scaling relation between the magnetoresistance, thermal conductivity and σxy\sigma_{xy}.Comment: 6 pages, 7 figures Intro para slightly lengthened. Added 2 new re

    The Nernst effect in high-TcT_c superconductors

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    The observation of a large Nernst signal eNe_N in an extended region above the critical temperature TcT_c in hole-doped cuprates provides evidence that vortex excitations survive above TcT_c. The results support the scenario that superfluidity vanishes because long-range phase coherence is destroyed by thermally-created vortices (in zero field), and that the pair condensate extends high into the pseudogap state in the underdoped (UD) regime. We present a series of measurements to high fields HH which provide strong evidence for this phase-disordering scenario.Comment: 21 pages, 28 figure

    Systematic review and evidence synthesis of non-cervical human papillomavirus-related disease health systems costs and quality of life estimates

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    BACKGROUND: Many economic evaluations of human papillomavirus vaccination should ideally consider multiple disease outcomes, including anogenital warts, respiratory papillomatosis and non-cervical cancers (eg, anal, oropharyngeal, penile, vulvar and vaginal cancers). However, published economic evaluations largely relied on estimates from single studies or informal rapid literature reviews. METHODS: We conducted a systematic review of articles up to June 2016 to identify costs and utility estimates admissible for an economic evaluation from a single-payer healthcare provider's perspective. Meta-analyses were performed for studies that used same utility elicitation tools for similar diseases. Costs were adjusted to 2016/2017 US.RESULTS:Sixtyonepapers(35costs;24utilities;2costsandutilities)wereselectedfrom10742initialrecords.CostpercaserangeswereUS. RESULTS: Sixty-one papers (35 costs; 24 utilities; 2 costs and utilities) were selected from 10 742 initial records. Cost per case ranges were US124-US883(anogenitalwarts),US883 (anogenital warts), US6912-US52579(headandneckcancers),US52 579 (head and neck cancers), US12 936-US51571(analcancer),US51 571 (anal cancer), US17 524-34 258 (vaginal cancer), US14686US14 686-US28 502 (vulvar cancer) and US9975US9975-US27 629 (penile cancer). The total cost for 14 adult patients with recurrent respiratory papillomatosis was US$137 601 (one paper).Utility per warts episode ranged from 0.651 to 1 (12 papers, various utility elicitation methods), with pooled mean EQ-5D and EQ-VAS of 0.86 (95% CI 0.85 to 0.87) and 0.74 (95% CI 0.74 to 0.75), respectively. Fifteen papers reported utilities in head and neck cancers with range 0.29 (95% CI 0.0 to 0.76) to 0.94 (95% CI 0.3 to 1.0). Mean utility reported ranged from 0.5 (95% CI 0.4 to 0.61) to 0.65 (95% CI 0.45 to 0.75) (anal cancer), 0.59 (95% CI 0.54 to 0.64) (vaginal cancer), 0.65 (95% CI 0.60 to 0.70) (vulvar cancer) and 0.79 (95% CI 0.74 to 0.84) (penile cancer). CONCLUSIONS: Differences in values reported from each paper reflect variations in cancer site, disease stages, study population, treatment modality/setting and utility elicitation methods used. As patient management changes over time, corresponding effects on both costs and utility need to be considered to ensure health economic assumptions are up-to-date and closely reflect the case mix of patients

    Circuit QED with a Nonlinear Resonator : ac-Stark Shift and Dephasing

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    We have performed spectroscopic measurements of a superconducting qubit dispersively coupled to a nonlinear resonator driven by a pump microwave field. Measurements of the qubit frequency shift provide a sensitive probe of the intracavity field, yielding a precise characterization of the resonator nonlinearity. The qubit linewidth has a complex dependence on the pump frequency and amplitude, which is correlated with the gain of the nonlinear resonator operated as a small-signal amplifier. The corresponding dephasing rate is found to be close to the quantum limit in the low-gain limit of the amplifier.Comment: Paper : 4 pages, 3 figures; Supplementary material : 1 page, 1 figur
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