34 research outputs found

    The Atmospheric Coupling and Dynamics Across the Mesopause (ACaDAMe) mission

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    The Atmospheric Coupling and Dynamics Across the Mesopause (ACaDAMe) is a mission designed to uniquely address critical questions involving multi-scale wave dynamics at key space weather (SWx) ā€œgateway altitudesā€ of the mesosphere and lower thermosphere (MLT) at āˆ¼70ā€“150ā€Ækm. ACaDAMe observes with a nadir-pointing resonant lidar that utilizes the fluorescence of atomic Na present in the MLT. By tuning a laser to the Na absorption wavelength (589ā€Ænm), ACaDAMe would perform very high resolution measurements of temperature and Na densities across the mesopause during both day and night. In this manner, Na is used as tracer for observing and characterizing MLT waves generated by tropospheric weather that represent the dominant terrestrial source of energy and momentum affecting space weather and transport of mesospheric species

    The predictability of the extratropical stratosphere on monthly time-scales and its impact on the skill of tropospheric forecasts

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    This is the final version of the article. Available from Wiley via the DOI in this record.Extreme variability of the winter- and spring-time stratospheric polar vortex has been shown to affect extratropical tropospheric weather. Therefore, reducing stratospheric forecast error may be one way to improve the skill of tropospheric weather forecasts. In this review, the basis for this idea is examined. A range of studies of different stratospheric extreme vortex events shows that they can be skilfully forecasted beyond 5 days and into the sub-seasonal range (0ā€“30 days) in some cases. Separate studies show that typical errors in forecasting a stratospheric extreme vortex event can alter tropospheric forecast skill by 5ā€“7% in the extratropics on sub-seasonal time-scales. Thus understanding what limits stratospheric predictability is of significant interest to operational forecasting centres. Both limitations in forecasting tropospheric planetary waves and stratospheric model biases have been shown to be important in this context.This work is supported by the Natural Environmental Research Council (NERC) funded project Stratospheric Network for the Assessment of Predictability (SNAP) (Grant H5147600) and partially supported by the SPARC. ACP and RGH acknowledge funding through the EU ARISE project (Grant 284387) (EU-FP7). We also acknowledge Steven Pawson and Lawrence Coy from NASA for providing Figure 1. We wish to thank Lorenzo Polvani from Columbia University for providing Figure 4 and Amy Butler from NOAA for her contribution to Figure 5. We thank Adrian Simmons of ECMWF for his insightful review and two anonymous reviewers for their comments and suggestions that improved the quality of the manuscript

    Largeā€Amplitude Mountain Waves in the Mesosphere Accompanying Weak Crossā€Mountain Flow During DEEPWAVE Research Flight RF22

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    Mountain wave (MW) propagation and dynamics extending into the upper mesosphere accompanying weak forcing are examined using in situ and remoteā€sensing measurements aboard the National Science Foundation/National Center for Atmospheric Research Gulfstream V (GV) research aircraft and the German Aerospace Center Falcon. The measurements were obtained during Falcon flights FF9 and FF10 and GV Research Flight RF22 of the Deep Propagating Gravity Wave Experiment (DEEPWAVE) performed over Mount Cook, New Zealand, on 12 and 13 July 2014. In situ measurements revealed both trapped lee waves having zonal wavelengths of Ī»ā‚“ ~ 12 km and less, and largerā€scale, vertically propagating MWs primarily at Ī»ā‚“ ~ 20ā€“60 km and ~100ā€“300 km extending from west to ~400 km east of Mount Cook. GV Rayleigh lidar measurements from 25ā€ to 60ā€km altitudes showed that the weak forcing and zonal winds that increased from ~12 m/s at 12 km to ~40 and 130 m/s at 30 and 55 km, respectively, enabled largely linear MW propagation and strong amplitude growth with altitude into the mesosphere. GV Na lidar and airglow imager measurements revealed an extensive MW response from ~70 to 87 km with large amplitudes and vertical displacements at Ī»ā‚“ ~ 40ā€“300 km but with both decreasing with altitude approaching a critical level near 90 km. These MWs exhibited largeā€scale MW breaking and among the largest sustained momentum fluxes observed in the mesosphere. UK Met Office Unified Model simulations of the RF22 MW event captured many aspects of the observed MW field and revealed that despite the dominant largeā€scale MW responses in the stratosphere, the major momentum fluxes accompanied smallerā€scale waves

    Economic evaluation of chemoprevention of breast cancer with tamoxifen and raloxifene among high-risk women in Japan

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    Raloxifene was approved for chemoprevention against breast cancer among high-risk women in addition to tamoxifen by the US Food and Drug Administration. This study aims to evaluate cost-effectiveness of these agents under Japan's health system. A cost-effectiveness analysis with Markov model consisting of eight health states such as healthy, invasive breast cancer, and endometrial cancer is carried out. The model incorporated the findings of National Surgical Adjuvant Breast and Bowel Project P-1 and P-2 trial, and key costs obtained from health insurance claim reviews. Favourable results, that is cost saving or cost-effective, are found by both tamoxifen and raloxifene for the introduction of chemoprevention among extremely high-risk women such as having a history of atypical hyperplasia, a history of lobular carcinoma in situ or a 5-year predicted breast cancer risk of ā©¾5.01% starting at younger age, whereas unfavourable results, that is ā€˜cost more and gain less' or cost-ineffective, are found for women with a 5-year predicted breast cancer risk of ā©½5.00%. Therapeutic policy switch from tamoxifen to raloxifene among postmenopausal women are implied cost-effective. Findings suggest that introduction of chemoprevention targeting extremely high-risk women in Japan can be justifiable as an efficient use of finite health-care resources, possibly contributing to cost containment

    A mixed model QTL analysis for sugarcane multiple-harvest-location trial data

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    Sugarcane-breeding programs take at least 12Ā years to develop new commercial cultivars. Molecular markers offer a possibility to study the genetic architecture of quantitative traits in sugarcane, and they may be used in marker-assisted selection to speed up artificial selection. Although the performance of sugarcane progenies in breeding programs are commonly evaluated across a range of locations and harvest years, many of the QTL detection methods ignore two- and three-way interactions between QTL, harvest, and location. In this work, a strategy for QTL detection in multi-harvest-location trial data, based on interval mapping and mixed models, is proposed and applied to map QTL effects on a segregating progeny from a biparental cross of pre-commercial Brazilian cultivars, evaluated at two locations and three consecutive harvest years for cane yield (tonnes per hectare), sugar yield (tonnes per hectare), fiber percent, and sucrose content. In the mixed model, we have included appropriate (co)variance structures for modeling heterogeneity and correlation of genetic effects and non-genetic residual effects. Forty-six QTLs were found: 13 QTLs for cane yield, 14 for sugar yield, 11 for fiber percent, and 8 for sucrose content. In addition, QTL by harvest, QTL by location, and QTL by harvest by location interaction effects were significant for all evaluated traits (30 QTLs showed some interaction, and 16 none). Our results contribute to a better understanding of the genetic architecture of complex traits related to biomass production and sucrose content in sugarcane

    Cost effectiveness thresholds: the past, the present and the future

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    Cost-effectiveness (CE) thresholds are being discussed more frequently and there have been many new developments in this area; however, there is a lack of understanding about what thresholds mean and their implications. This paper provides an overview of the CE threshold literature. First, the meaning of a CE threshold and the key assumptions involved (perfect divisibility, marginal increments in budget, etc.) are highlighted using a hypothetical example, and the use of historic/heuristic estimates of the threshold is noted along with their limitations. Recent endeavours to estimate the empirical value of the thresholds, both from the supply side and the demand side, are then presented. The impact on CE thresholds of future directions for the field, such as thresholds across sectors and the incorporation of multiple criteria beyond quality-adjusted life-years as a measure of ā€˜valueā€™, are highlighted. Finally, a number of common issues and misconceptions associated with CE thresholds are addressed

    Momentum Flux Spectra of a Mountain Wave Event Over New Zealand

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    During the Deep Propagating Gravity Wave Experiment (DEEPWAVE) 13 July 2014 research flight over the South Island of New Zealand, a multiscale spectrum of mountain waves (MWs) was observed. Highā€resolution measurements of sodium densities were available from ~70 to 100 km for the duration of this flight. A comprehensive technique is presented for obtaining temperature perturbations, Tā€², from sodium mixing ratios over a range of altitudes, and these Tā€² were used to calculate the momentum flux (MF) spectra with respect to horizontal wavelengths, Ī»H, for each flight segment. Spectral analysis revealed MWs with spectral power centered at Ī»H of ~80, 120, and 220 km. The temperature amplitudes of these MWs varied between the four crossā€mountain flight legs occurring between 6:10UT and 9:10UT. The average spectral Tā€² amplitudes near 80 km in altitude ranged from 7ā€“13 K for the 220 km Ī»H MW and 4ā€“8 K for the smaller Ī»H MWs. These amplitudes decayed significantly up to 90 km, where a critical level for MWs was present. The average MF per unit mass near 80 km in altitude ranged from ~13 to 60 mĀ²/sĀ² across the varying spectra over the duration of the research flight and decayed to ~0 by 88 km in altitude. These MFs are large compared to zonal means and highlight the importance of MWs in the momentum budget of the mesosphere and lower thermosphere at times when they reach these altitudes
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