7,760 research outputs found

    Tourism and the smartphone app: capabilities, emerging practice and scope in the travel domain.

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    Based on its advanced computing capabilities and ubiquity, the smartphone has rapidly been adopted as a tourism travel tool.With a growing number of users and a wide varietyof applications emerging, the smartphone is fundamentally altering our current use and understanding of the transport network and tourism travel. Based on a review of smartphone apps, this article evaluates the current functionalities used in the domestic tourism travel domain and highlights where the next major developments lie. Then, at a more conceptual level, the article analyses how the smartphone mediates tourism travel and the role it might play in more collaborative and dynamic travel decisions to facilitate sustainable travel. Some emerging research challenges are discussed

    Tests of star formation metrics in the low metallicity galaxy NGC 5253 using ALMA observations of H30α\alpha line emission

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    We use Atacama Large Millimeter/submillimeter Array (ALMA) observations of H30α\alpha (231.90 GHz) emission from the low metallicity dwarf galaxy NGC 5253 to measure the star formation rate (SFR) within the galaxy and to test the reliability of SFRs derived from other commonly-used metrics. The H30α\alpha emission, which originates mainly from the central starburst, yields a photoionizing photon production rate of (1.9±\pm0.3)×\times1052^{52} s−1^{-1} and an SFR of 0.087±\pm0.013 M⊙_\odot yr−1^{-1} based on conversions that account for the low metallicity of the galaxy and for stellar rotation. Among the other star formation metrics we examined, the SFR calculated from the total infrared flux was statistically equivalent to the values from the H30α\alpha data. The SFR based on previously-published versions of the Hα\alpha flux that were extinction corrected using Paα\alpha and Paβ\beta lines were lower than but also statistically similar to the H30α\alpha value. The mid-infrared (22 μ\mum) flux density and the composite star formation tracer based on Hα\alpha and mid-infrared emission give SFRs that were significantly higher because the dust emission appears unusually hot compared to typical spiral galaxies. Conversely, the 70 and 160 μ\mum flux densities yielded SFR lower than the H30α\alpha value, although the SFRs from the 70 μ\mum and H30α\alpha data were within 1-2σ\sigma of each other. While further analysis on a broader range of galaxies are needed, these results are instructive of the best and worst methods to use when measuring SFR in low metallicity dwarf galaxies like NGC 5253.Comment: 14 pages, 5 figures, accepted for publication in MNRA

    Dispersity-Driven Melting Transition in Two Dimensional Solids

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    We perform extensive simulations of 10410^4 Lennard-Jones particles to study the effect of particle size dispersity on the thermodynamic stability of two-dimensional solids. We find a novel phase diagram in the dispersity-density parameter space. We observe that for large values of the density there is a threshold value of the size dispersity above which the solid melts to a liquid along a line of first order phase transitions. For smaller values of density, our results are consistent with the presence of an intermediate hexatic phase. Further, these findings support the possibility of a multicritical point in the dispersity-density parameter space.Comment: In revtex format, 4 pages, 6 postscript figures. Submitted to PR

    Ledipasvir-Sofosbuvir for treating Chronic Hepatitis C: A NICE Single Technology Appraisal - An Evidence Review Group Perspective

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    The National Institute for Health and Care Excellence (NICE) invited Gilead, the company manufacturing ledipasvir-sofosbuvir (LDV/SOF), to submit evidence for the clinical effectiveness and cost-effectiveness of LDV/SOF for treating Chronic Hepatitis C. The School of Health and Related Research (ScHARR) Technology Assessment Group was commissioned as the Evidence Review Group (ERG). This paper describes the company’s submission (CS), the ERG review and the subsequent decision of the NICE Appraisal Committee (AC). The ERG produced a critical review of the clinical effectiveness and cost-effectiveness evidence of LDV/SOF based upon the CS. The clinical effectiveness data for LDV/SOF were taken from ten trials, comprised of three Phase III trials and seven Phase II trials. Trials compared different durations of LDV/SOF, with and without ribavirin (RBV). There were no head-to-head trials comparing LDV/SOF with any comparator listed in the NICE scope. Data from the trials were mostly from populations with genotype 1 (GT1) disease, although some limited data were available for populations with genotypes 3 and 4. For GT1 treatment-naïve patients, sustained viral response for 12 weeks (SVR12) rates for LDV/SOF ranged from 93.1% to 99.4% for subgroups of patients with non-cirrhotic disease, whilst SVR rates of 94.1% to 100% were reported for subgroups of patients with compensated cirrhosis. For GT1 treatment-experienced patients, SVR12 rates ranging from 95.4% to 100% were reported for subgroups of non-cirrhotic patients and SVR rates ranging from 81.8% to 100% were reported within subgroups of patients with compensated cirrhosis. Comparator data were not searched systematically as part of the submission, but were based on the company’s previous NICE submission of sofosbuvir, with additional targeted searches. The ERG’s critical appraisal of the company’s economic evaluation highlighted a number of concerns. The ERG’s base case analyses suggested that the incremental cost effectiveness ratios (ICERs) for LDV/SOF (+RBV) are dependent on a) treatment durations, b) whether patients have been previously treated and c) whether patients have liver cirrhosis or not. The AC concluded that it was appropriate to use the approach taken in the ERG’s exploratory analyses, in line with the marketing authorisation, which considered people with and without cirrhosis separately, and estimated the cost-effectiveness for each recommended treatment duration of LDV/SOF

    Families' social backgrounds matter : socio-economic factors, home learning and young children's language, literacy and social outcomes

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    Parental support with children's learning is considered to be one pathway through which socio-economic factors influence child competencies. Utilising a national longitudinal sample from the Millennium Cohort Study, this study examined the relationship between home learning and parents' socio-economic status and their impact on young children's language/literacy and socio-emotional competence. The findings consistently showed that, irrespective of socio-economic status, parents engaged with various learning activities (except reading) roughly equally. The socio-economic factors examined in this study, i.e., family income and maternal educational qualifications, were found to have a stronger effect on children's language/literacy than on social-emotional competence. Socio-economic disadvantage, lack of maternal educational qualifications in particular, remained powerful in influencing competencies in children aged three and at the start of primary school. For children in the first decade of this century in England, these findings have equity implications, especially as the socio-economic gap in our society widens

    IR-correlated 31 GHz radio emission from Orion East

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    Lynds dark cloud LDN1622 represents one of the best examples of anomalous dust emission, possibly originating from small spinning dust grains. We present Cosmic Background Imager (CBI) 31 GHz data of LDN1621, a diffuse dark cloud to the north of LDN1622 in a region known as Orion East. A broken ring with diameter g\approx 20 arcmin of diffuse emission is detected at 31 GHz, at \approx 20-30 mJy beam−1^{-1} with an angular resolution of \approx 5 arcmin. The ring-like structure is highly correlated with Far Infra-Red emission at 12−100μ12-100 \mum with correlation coefficients of r \approx 0.7-0.8, significant at ∼10σ\sim10\sigma. Multi-frequency data are used to place constraints on other components of emission that could be contributing to the 31 GHz flux. An analysis of the GB6 survey maps at 4.85 GHz yields a 3σ3\sigma upper limit on free-free emission of 7.2 mJy beam−1^{-1} (\la 30 per cent of the observed flux) at the CBI resolution. The bulk of the 31 GHz flux therefore appears to be mostly due to dust radiation. Aperture photometry, at an angular resolution of 13 arcmin and with an aperture of diameter 30 arcmin, allowed the use of IRAS maps and the {\it WMAP} 5-year W-band map at 93.5 GHz. A single modified blackbody model was fitted to the data to estimate the contribution from thermal dust, which amounts to \sim10percentat31GHz.Inthismodel,anexcessof1.52±0.66Jy(2.3σ)isseenat31GHz.Futurehighfrequency 10 per cent at 31 GHz. In this model, an excess of 1.52\pm 0.66 Jy (2.3\sigma) is seen at 31 GHz. Future high frequency \sim100−1000GHzdata,suchasthosefromthePlancksatellite,arerequiredtoaccuratelydeterminethethermaldustcontributionat31GHz.CorrelationswiththeIRAS 100-1000 GHz data, such as those from the {\it Planck} satellite, are required to accurately determine the thermal dust contribution at 31 GHz. Correlations with the IRAS 100 \mumgaveacouplingcoefficientofm gave a coupling coefficient of 18.1\pm4.4 \muK(MJy/sr)K (MJy/sr)^{-1}$, consistent with the values found for LDN1622.Comment: 8 pages, 3 figures, 3 tables, submitted to MNRA
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