1. |
- Lind, Lars, et al.
(författare)
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Heterogeneous contributions of change in population distribution of body mass index to change in obesity and underweight NCD Risk Factor Collaboration (NCD-RisC)
- 2021
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Ingår i: eLife. - : eLife Sciences Publications Ltd. - 2050-084X. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- From 1985 to 2016, the prevalence of underweight decreased, and that of obesity and severe obesity increased, in most regions, with significant variation in the magnitude of these changes across regions. We investigated how much change in mean body mass index (BMI) explains changes in the prevalence of underweight, obesity, and severe obesity in different regions using data from 2896 population-based studies with 187 million participants. Changes in the prevalence of underweight and total obesity, and to a lesser extent severe obesity, are largely driven by shifts in the distribution of BMI, with smaller contributions from changes in the shape of the distribution. In East and Southeast Asia and sub-Saharan Africa, the underweight tail of the BMI distribution was left behind as the distribution shifted. There is a need for policies that address all forms of malnutrition by making healthy foods accessible and affordable, while restricting unhealthy foods through fiscal and regulatory restrictions.
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2. |
- Bixby, H., et al.
(författare)
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Rising rural body-mass index is the main driver of the global obesity epidemic in adults
- 2019
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 569:7755, s. 260-4
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Tidskriftsartikel (refereegranskat)abstract
- Body-mass index (BMI) has increased steadily in most countries in parallel with a rise in the proportion of the population who live in cities(.)(1,2) This has led to a widely reported view that urbanization is one of the most important drivers of the global rise in obesity(3-6). Here we use 2,009 population-based studies, with measurements of height and weight in more than 112 million adults, to report national, regional and global trends in mean BMI segregated by place of residence (a rural or urban area) from 1985 to 2017. We show that, contrary to the dominant paradigm, more than 55% of the global rise in mean BMI from 1985 to 2017-and more than 80% in some low- and middle-income regions-was due to increases in BMI in rural areas. This large contribution stems from the fact that, with the exception of women in sub-Saharan Africa, BMI is increasing at the same rate or faster in rural areas than in cities in low- and middle-income regions. These trends have in turn resulted in a closing-and in some countries reversal-of the gap in BMI between urban and rural areas in low- and middle-income countries, especially for women. In high-income and industrialized countries, we noted a persistently higher rural BMI, especially for women. There is an urgent need for an integrated approach to rural nutrition that enhances financial and physical access to healthy foods, to avoid replacing the rural undernutrition disadvantage in poor countries with a more general malnutrition disadvantage that entails excessive consumption of low-quality calories.
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3. |
- Mishra, A, et al.
(författare)
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Diminishing benefits of urban living for children and adolescents' growth and development
- 2023
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 1476-4687 .- 0028-0836. ; 615:7954, s. 874-883
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Tidskriftsartikel (refereegranskat)abstract
- Optimal growth and development in childhood and adolescence is crucial for lifelong health and well-being1–6. Here we used data from 2,325 population-based studies, with measurements of height and weight from 71 million participants, to report the height and body-mass index (BMI) of children and adolescents aged 5–19 years on the basis of rural and urban place of residence in 200 countries and territories from 1990 to 2020. In 1990, children and adolescents residing in cities were taller than their rural counterparts in all but a few high-income countries. By 2020, the urban height advantage became smaller in most countries, and in many high-income western countries it reversed into a small urban-based disadvantage. The exception was for boys in most countries in sub-Saharan Africa and in some countries in Oceania, south Asia and the region of central Asia, Middle East and north Africa. In these countries, successive cohorts of boys from rural places either did not gain height or possibly became shorter, and hence fell further behind their urban peers. The difference between the age-standardized mean BMI of children in urban and rural areas was <1.1 kg m–2 in the vast majority of countries. Within this small range, BMI increased slightly more in cities than in rural areas, except in south Asia, sub-Saharan Africa and some countries in central and eastern Europe. Our results show that in much of the world, the growth and developmental advantages of living in cities have diminished in the twenty-first century, whereas in much of sub-Saharan Africa they have amplified.
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4. |
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5. |
- Fenstermacher, M.E., et al.
(författare)
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DIII-D research advancing the physics basis for optimizing the tokamak approach to fusion energy
- 2022
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 62:4
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Tidskriftsartikel (refereegranskat)abstract
- DIII-D physics research addresses critical challenges for the operation of ITER and the next generation of fusion energy devices. This is done through a focus on innovations to provide solutions for high performance long pulse operation, coupled with fundamental plasma physics understanding and model validation, to drive scenario development by integrating high performance core and boundary plasmas. Substantial increases in off-axis current drive efficiency from an innovative top launch system for EC power, and in pressure broadening for Alfven eigenmode control from a co-/counter-I p steerable off-axis neutral beam, all improve the prospects for optimization of future long pulse/steady state high performance tokamak operation. Fundamental studies into the modes that drive the evolution of the pedestal pressure profile and electron vs ion heat flux validate predictive models of pedestal recovery after ELMs. Understanding the physics mechanisms of ELM control and density pumpout by 3D magnetic perturbation fields leads to confident predictions for ITER and future devices. Validated modeling of high-Z shattered pellet injection for disruption mitigation, runaway electron dissipation, and techniques for disruption prediction and avoidance including machine learning, give confidence in handling disruptivity for future devices. For the non-nuclear phase of ITER, two actuators are identified to lower the L-H threshold power in hydrogen plasmas. With this physics understanding and suite of capabilities, a high poloidal beta optimized-core scenario with an internal transport barrier that projects nearly to Q = 10 in ITER at ∼8 MA was coupled to a detached divertor, and a near super H-mode optimized-pedestal scenario with co-I p beam injection was coupled to a radiative divertor. The hybrid core scenario was achieved directly, without the need for anomalous current diffusion, using off-axis current drive actuators. Also, a controller to assess proximity to stability limits and regulate β N in the ITER baseline scenario, based on plasma response to probing 3D fields, was demonstrated. Finally, innovative tokamak operation using a negative triangularity shape showed many attractive features for future pilot plant operation.
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6. |
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7. |
- Taddei, C, et al.
(författare)
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Repositioning of the global epicentre of non-optimal cholesterol
- 2020
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 1476-4687 .- 0028-0836. ; 582:7810, s. 73-
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Tidskriftsartikel (refereegranskat)abstract
- High blood cholesterol is typically considered a feature of wealthy western countries1,2. However, dietary and behavioural determinants of blood cholesterol are changing rapidly throughout the world3 and countries are using lipid-lowering medications at varying rates. These changes can have distinct effects on the levels of high-density lipoprotein (HDL) cholesterol and non-HDL cholesterol, which have different effects on human health4,5. However, the trends of HDL and non-HDL cholesterol levels over time have not been previously reported in a global analysis. Here we pooled 1,127 population-based studies that measured blood lipids in 102.6 million individuals aged 18 years and older to estimate trends from 1980 to 2018 in mean total, non-HDL and HDL cholesterol levels for 200 countries. Globally, there was little change in total or non-HDL cholesterol from 1980 to 2018. This was a net effect of increases in low- and middle-income countries, especially in east and southeast Asia, and decreases in high-income western countries, especially those in northwestern Europe, and in central and eastern Europe. As a result, countries with the highest level of non-HDL cholesterol—which is a marker of cardiovascular risk—changed from those in western Europe such as Belgium, Finland, Greenland, Iceland, Norway, Sweden, Switzerland and Malta in 1980 to those in Asia and the Pacific, such as Tokelau, Malaysia, The Philippines and Thailand. In 2017, high non-HDL cholesterol was responsible for an estimated 3.9 million (95% credible interval 3.7 million–4.2 million) worldwide deaths, half of which occurred in east, southeast and south Asia. The global repositioning of lipid-related risk, with non-optimal cholesterol shifting from a distinct feature of high-income countries in northwestern Europe, north America and Australasia to one that affects countries in east and southeast Asia and Oceania should motivate the use of population-based policies and personal interventions to improve nutrition and enhance access to treatment throughout the world.
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8. |
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9. |
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10. |
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11. |
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12. |
- de Jong, R. S., et al.
(författare)
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4MOST : Project overview and information for the First Call for Proposals
- 2019
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Ingår i: The Messenger. - : European Southern Observatory. - 0722-6691. ; 175, s. 3-11
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- We introduce the 4-metre Multi-Object Spectroscopic Telescope (4MOST), a new high-multiplex, wide-field spectroscopic survey facility under development for the four-metre-class Visible and Infrared Survey Telescope for Astronomy (VISTA) at Paranal. Its key specifications are: a large field of view (FoV) of 4.2 square degrees and a high multiplex capability, with 1624 fibres feeding two low-resolution spectrographs (R = λ/Δλ ~ 6500), and 812 fibres transferring light to the high-resolution spectrograph (R ~ 20 000). After a description of the instrument and its expected performance, a short overview is given of its operational scheme and planned 4MOST Consortium science; these aspects are covered in more detail in other articles in this edition of The Messenger. Finally, the processes, schedules, and policies concerning the selection of ESO Community Surveys are presented, commencing with a singular opportunity to submit Letters of Intent for Public Surveys during the first five years of 4MOST operations.
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13. |
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14. |
- Smartt, S. J., et al.
(författare)
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PESSTO : survey description and products from the first data release by the Public ESO Spectroscopic Survey of Transient Objects
- 2015
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 579
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Tidskriftsartikel (refereegranskat)abstract
- Context. The Public European Southern Observatory Spectroscopic Survey of Transient Objects (PESSTO) began as a public spectroscopic survey in April 2012. PESSTO classifies transients from publicly available sources and wide-field surveys, and selects science targets for detailed spectroscopic and photometric follow-up. PESSTO runs for nine months of the year, January - April and August - December inclusive, and typically has allocations of 10 nights per month. Aims. We describe the data reduction strategy and data products that are publicly available through the ESO archive as the Spectroscopic Survey data release 1 (SSDR1). Methods. PESSTO uses the New Technology Telescope with the instruments EFOSC2 and SOFI to provide optical and NIR spectroscopy and imaging. We target supernovae and optical transients brighter than 20.5(m) for classification. Science targets are selected for follow-up based on the PESSTO science goal of extending knowledge of the extremes of the supernova population. We use standard EFOSC2 set-ups providing spectra with resolutions of 13-18 angstrom between 3345-9995 angstrom. A subset of the brighter science targets are selected for SOFI spectroscopy with the blue and red grisms (0.935-2.53 mu m and resolutions 23-33 angstrom) and imaging with broadband JHK(s) filters. Results. This first data release (SSDR1) contains flux calibrated spectra from the first year (April 2012-2013). A total of 221 confirmed supernovae were classified, and we released calibrated optical spectra and classifications publicly within 24 h of the data being taken (via WISeREP). The data in SSDR1 replace those released spectra. They have more reliable and quantifiable flux calibrations, correction for telluric absorption, and are made available in standard ESO Phase 3 formats. We estimate the absolute accuracy of the flux calibrations for EFOSC2 across the whole survey in SSDR1 to be typically similar to 15%, although a number of spectra will have less reliable absolute flux calibration because of weather and slit losses. Acquisition images for each spectrum are available which, in principle, can allow the user to refine the absolute flux calibration. The standard NIR reduction process does not produce high accuracy absolute spectrophotometry but synthetic photometry with accompanying JHK(s) imaging can improve this. Whenever possible, reduced SOFI images are provided to allow this. Conclusions. Future data releases will focus on improving the automated flux calibration of the data products. The rapid turnaround between discovery and classification and access to reliable pipeline processed data products has allowed early science papers in the first few months of the survey.
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15. |
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16. |
- Bentham, James, et al.
(författare)
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A century of trends in adult human height
- 2016
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Ingår i: eLIFE. - : eLife Sciences Publications Ltd. - 2050-084X. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.5–22.7) and 16.5 cm (13.3– 19.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8– 144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries.
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17. |
- Valenti, S., et al.
(författare)
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PESSTO spectroscopic classification of La Silla-Quest Transients
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- PESSTO is the "Public ESO Spectroscopic Survey of Transient Objects" (http://www.pessto.org) using the ESO New Technology Telescope (NTT) at La Silla and the EFOSC2 (optical) and SOFI (near-IR) spectrographs. It is one of two currently running public spectroscopic surveys at ESO. The survey details are as follows: - PESSTO has 90 nights per year on the NTT: 9 lunations (August to April), 10 nights per lunation (we are not observing May-July).
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18. |
- Bentham, James, et al.
(författare)
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A century of trends in adult human height
- 2016
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Ingår i: eLIFE. - 2050-084X. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.522.7) and 16.5 cm (13.319.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries.
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19. |
- Léget, P. -F., et al.
(författare)
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Correcting for peculiar velocities of Type la supernovae in clusters of galaxies
- 2018
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 615
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Tidskriftsartikel (refereegranskat)abstract
- Context. Type Ia supernovae (SNe Ia) are widely used to measure the expansion of the Universe. To perform such measurements the luminosity and cosmological redshift (z) of the SNe Ia have to be determined. The uncertainty on z includes an unknown peculiar velocity, which can be very large for SNe Ia in the virialized cores of massive clusters. Aims. We determine which SNe Ia exploded in galaxy clusters using 145 SNe Ia from the Nearby Supernova Factory. We then study how the correction for peculiar velocities of host galaxies inside the clusters improves the Hubble residuals. Methods. We found 11 candidates for membership in clusters. We applied the biweight technique to estimate the redshift of a cluster. Then, we used the galaxy cluster redshift instead of the host galaxy redshift to construct the Hubble diagram. Results. For SNe Ia inside galaxy clusters, the dispersion around the Hubble diagram when peculiar velocities are taken into account is smaller compared with a case without peculiar velocity correction, which has a wRMS = 0.130 +/- 0.038 mag instead of wRMS = 0.137 +/- 0.036 mag. The significance of this improvement is 3.58 sigma. If we remove the very nearby Virgo cluster member SN2006X (z < 0.01) from the analysis, the significance decreases to 1.34 sigma. The peculiar velocity correction is found to be highest for the SNe Ia hosted by blue spiral galaxies. Those SNe Ia have high local specific star formation rates and smaller stellar masses, which is seemingly counter to what might be expected given the heavy concentration of old, massive elliptical galaxies in clusters. Conclusions. As expected, the Hubble residuals of SNe Ia associated with massive galaxy clusters improve when the cluster redshift is taken as the cosmological redshift of the supernova. This fact has to be taken into account in future cosmological analyses in order to achieve higher accuracy for cosmological redshift measurements. We provide an approach to do so.
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20. |
- Léget, P-F, et al.
(författare)
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SUGAR : An improved empirical model of Type Ia supernovae based on spectral features
- 2020
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 636
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Tidskriftsartikel (refereegranskat)abstract
- Context. Type Ia supernovae (SNe Ia) are widely used to measure the expansion of the Universe. Improving distance measurements of SNe Ia is one technique to better constrain the acceleration of expansion and determine its physical nature.Aims. This document develops a new SNe Ia spectral energy distribution (SED) model, called the SUpernova Generator And Reconstructor (SUGAR), which improves the spectral description of SNe Ia, and consequently could improve the distance measurements.Methods. This model was constructed from SNe Ia spectral properties and spectrophotometric data from the Nearby Supernova Factory collaboration. In a first step, a principal component analysis-like method was used on spectral features measured at maximum light, which allowed us to extract the intrinsic properties of SNe Ia. Next, the intrinsic properties were used to extract the average extinction curve. Third, an interpolation using Gaussian processes facilitated using data taken at different epochs during the lifetime of an SN Ia and then projecting the data on a fixed time grid. Finally, the three steps were combined to build the SED model as a function of time and wavelength. This is the SUGAR model.Results. The main advancement in SUGAR is the addition of two additional parameters to characterize SNe Ia variability. The first is tied to the properties of SNe Ia ejecta velocity and the second correlates with their calcium lines. The addition of these parameters, as well as the high quality of the Nearby Supernova Factory data, makes SUGAR an accurate and efficient model for describing the spectra of normal SNe Ia as they brighten and fade.Conclusions. The performance of this model makes it an excellent SED model for experiments like the Zwicky Transient Facility, the Large Synoptic Survey Telescope, or the Wide Field Infrared Survey Telescope.
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21. |
- Lombardo, S., et al.
(författare)
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SCALA : In situ calibration for integral field spectrographs
- 2017
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 607
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Tidskriftsartikel (refereegranskat)abstract
- Aims. The scientific yield of current and future optical surveys is increasingly limited by systematic uncertainties in the flux calibration. This is the case for type Ia supernova (SN Ia) cosmology programs, where an improved calibration directly translates into improved cosmological constraints. Current methodology rests on models of stars. Here we aim to obtain flux calibration that is traceable to state-of-the-art detector-based calibration. Methods. We present the SNIFS Calibration Apparatus (SCALA), a color (relative) flux calibration system developed for the SuperNova integral field spectrograph (SNIFS), operating at the University of Hawaii 2.2 m (UH 88) telescope. Results. By comparing the color trend of the illumination generated by SCALA during two commissioning runs, and to previous laboratory measurements, we show that we can determine the light emitted by SCALA with a long-term repeatability better than 1%. We describe the calibration procedure necessary to control for system aging. We present measurements of the SNIFS throughput as estimated by SCALA observations. Conclusions. The SCALA calibration unit is now fully deployed at the UH 88 telescope, and with it color-calibration between 4000 angstrom and 9000 angstrom is stable at the percent level over a one-year baseline.
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22. |
- Nordin, J., et al.
(författare)
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Understanding type Ia supernovae through their U-band spectra
- 2018
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 614
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Tidskriftsartikel (refereegranskat)abstract
- Context. Observations of type Ia supernovae (SNe Ia) can be used to derive accurate cosmological distances through empirical standardization techniques. Despite this success neither the progenitors of SNe Ia nor the explosion process are fully understood. The U-band region has been less well observed for nearby SNe, due to technical challenges, but is the most readily accessible band for high-redshift SNe. Aims. Using spectrophotometry from the Nearby Supernova Factory, we study the origin and extent of U-band spectroscopic variations in SNe Ia and explore consequences for their standardization and the potential for providing new insights into the explosion process. Methods. We divide the U-band spectrum into four wavelength regions lambda(uNi), lambda(uTi), lambda(uSi) and lambda(uCa). Two of these span the Ca H&K lambda lambda 3934, 3969 complex. We employ spectral synthesis using SYNAPPS to associate the two bluer regions with Ni/Co and Ti. Results. The flux of the uTi feature is an extremely sensitive temperature/ luminosity indicator, standardizing the SN peak luminosity to 0.116 +/- 0.011 mag root mean square (RMS). A traditional SALT2. 4 fit on the same sample yields a 0.135 mag RMS. Standardization using uTi also reduces the difference in corrected magnitude between SNe originating from different host galaxy environments. Early U-band spectra can be used to probe the Ni + Co distribution in the ejecta, thus offering a rare window into the source of light curve power. The uCa flux further improves standardization, yielding a 0.086 +/- 0.010 mag RMS without the need to include an additional intrinsic dispersion to reach chi(2) /dof similar to 1. This reduction in RMS is partially driven by an improved standardization of Shallow Silicon and 91T-like SNe.
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23. |
- Rigault, M., et al.
(författare)
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Strong dependence of Type Ia supernova standardization on the local specific star formation rate
- 2020
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 644
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Tidskriftsartikel (refereegranskat)abstract
- As part of an on-going effort to identify, understand and correct for astrophysics biases in the standardization of Type Ia supernovae (SN Ia) for cosmology, we have statistically classified a large sample of nearby SNe Ia into those that are located in predominantly younger or older environments. This classification is based on the specific star formation rate measured within a projected distance of 1 kpc from each SN location (LsSFR). This is an important refinement compared to using the local star formation rate directly, as it provides a normalization for relative numbers of available SN progenitors and is more robust against extinction by dust. We find that the SNe Ia in predominantly younger environments are ΔY = 0.163 ± 0.029 mag (5.7σ) fainter than those in predominantly older environments after conventional light-curve standardization. This is the strongest standardized SN Ia brightness systematic connected to the host-galaxy environment measured to date. The well-established step in standardized brightnesses between SNe Ia in hosts with lower or higher total stellar masses is smaller, at ΔM = 0.119 ± 0.032 mag (4.5σ), for the same set of SNe Ia. When fit simultaneously, the environment-age offset remains very significant, with ΔY = 0.129 ± 0.032 mag (4.0σ), while the global stellar mass step is reduced to ΔM = 0.064 ± 0.029 mag (2.2σ). Thus, approximately 70% of the variance from the stellar mass step is due to an underlying dependence on environment-based progenitor age. Also, we verify that using the local star formation rate alone is not as powerful as LsSFR at sorting SNe Ia into brighter and fainter subsets. Standardization that only uses the SNe Ia in younger environments reduces the total dispersion from 0.142 ± 0.008 mag to 0.120 ± 0.010 mag. We show that as environment-ages evolve with redshift, a strong bias, especially on the measurement of the derivative of the dark energy equation of state, can develop. Fortunately, data that measure and correct for this effect using our local specific star formation rate indicator, are likely to be available for many next-generation SN Ia cosmology experiments.
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24. |
- Sasdelli, Michele, et al.
(författare)
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A metric space for Type Ia supernova spectra
- 2015
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 447:2, s. 1247-1266
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Tidskriftsartikel (refereegranskat)abstract
- We develop a new framework for use in exploring Type Ia supernovae (SNe Ia) spectra. Combining principal component analysis (PCA) and partial least square (PLS) analysis we are able to establish correlations between the principal components (PCs) and spectroscopic/photometric SNe Ia features. The technique was applied to similar to 120 SN and similar to 800 spectra from the Nearby Supernova Factory. The ability of PCA to group together SNe Ia with similar spectral features, already explored in previous studies, is greatly enhanced by two important modifications: (1) the initial data matrix is built using derivatives of spectra over the wavelength, which increases the weight of weak lines and discards extinction, and (2) we extract time evolution information through the use of entire spectral sequences concatenated in each line of the input data matrix. These allow us to define a stable PC parameter space which can be used to characterize synthetic SN Ia spectra by means of real SN features. Using PLS, we demonstrate that the information from important previously known spectral indicators (namely the pseudo-equivalent width of Si II 5972 angstrom/Si II 6355 angstrom and the line veloci of S II 5640 angstrom/Si II 6355 angstrom) at a given epoch is contained within the PC space and can be determined through a linear combination of the most important PCs. We also show that the PC space encompasses photometric features like B/V magnitudes, B - V colours and SALT2 parameters c and x(1). The observed colours and magnitudes, which are heavily affected by extinction, cannot be reconstructed using this technique alone. All the above-mentioned applications allowed us to construct a metric space for comparing synthetic SN Ia spectra with observations.
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25. |
- Saunders, C., et al.
(författare)
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SNEMO : Improved Empirical Models for Type Ia Supernovae
- 2018
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 869:2
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Tidskriftsartikel (refereegranskat)abstract
- SN Ia cosmology depends on the ability to fit and standardize observations of supernova magnitudes with an empirical model. We present here a series of new models of SN Ia spectral time series that capture a greater amount of supernova diversity than is possible with the models that are currently customary. These are entitled SuperNova Empirical MOdels (SNEMO; https://snfactory.lbl.gov/snemo). The models are constructed using spectrophotometric time series from 172 individual supernovae from the Nearby Supernova Factory, comprising more than 2000 spectra. Using the available observations, Gaussian processes are used to predict a full spectral time series for each supernova. A matrix is constructed from the spectral time series of all the supernovae, and Expectation Maximization Factor Analysis is used to calculate the principal components of the data. K-fold cross-validation then determines the selection of model parameters and accounts for color variation in the data. Based on this process, the final models are trained on supernovae that have been dereddened using the Fitzpatrick and Massa extinction relation. Three final models are presented here: SNEMO2, a two-component model for comparison with current Type Ia models; SNEMO7, a seven-component model chosen for standardizing supernova magnitudes, which results in a total dispersion of 0.100mag for a validation set of supernovae, of which 0.087 mag is unexplained (a total dispersion of 0.113 mag with an unexplained dispersion of 0.097 mag is found for the total set of training and validation supernovae); and SNEMO15, a comprehensive 15-component model that maximizes the amount of spectral time-series behavior captured.
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26. |
- Taubenberger, S., et al.
(författare)
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SN2012dn from early to late times : 09dc-like supernovae reassessed
- 2019
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 488:4, s. 5473-5488
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Tidskriftsartikel (refereegranskat)abstract
- As a candidate super-Chandrasekhar' or 09dc-like TypeIa supernova (SNIa), SN 2012dn shares many characteristics with other members of this remarkable class of objects but lacks their extraordinary luminosity. Here, we present and discuss the most comprehensive optical data set of this SN to date, comprised of a densely sampled series of early-time spectra obtained within the Nearby Supernova Factory project, plus photometry and spectroscopy obtained at the Very Large Telescope about 1yr after the explosion. The light curves, colour curves, spectral time series, and ejecta velocities of SN 2012dn are compared with those of other 09dc-like and normal SNeIa, the overall variety within the class of 09dc-like SNeIa is discussed, and new criteria for 09dc-likeness are proposed. Particular attention is directed to additional insight that the late-phase data provide. The nebular spectra show forbidden lines of oxygen and calcium, elements that are usually not seen in late-time spectra of SNeIa, while the ionization state of the emitting iron plasma is low, pointing to low ejecta temperatures and high densities. The optical light curves are characterized by an enhanced fading starting similar to 60d after maximum and very low luminosities in the nebular phase, which is most readily explained by unusually early formation of clumpy dust in the ejecta. Taken together, these effects suggest a strongly perturbed ejecta density profile, which might lend support to the idea that 09dc-like characteristics arise from a brief episode of interaction with a hydrogen-deficient envelope during the first hours or days after the explosion.
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27. |
- Huang, X., et al.
(författare)
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The Extinction Properties of and Distance to the Highly Reddened Type IA Supernova 2012cu
- 2017
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 836:2
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Tidskriftsartikel (refereegranskat)abstract
- Correcting Type Ia Supernova brightnesses for extinction by dust has proven to be a vexing problem. Here we study the dust foreground to the highly reddened SN 2012cu, which is projected onto a dust lane in the galaxy NGC 4772. The analysis is based on multi-epoch, spectrophotometric observations spanning from 3300-9200 A degrees, obtained by the Nearby Supernova Factory. Phase-matched comparison of the spectroscopically twinned SN 2012cu and SN 2011fe across 10 epochs results in the best-fit color excess of (E(B-V), RMS) = (1.00, 0.03) and total-to-selective extinction ratio of (RV, RMS) = (2.95, 0.08) toward SN 2012cu within its host galaxy. We further identify several diffuse interstellar bands and compare the 5780 angstrom band with the dust- to-band ratio for the Milky Way (MW). Overall, we find the foreground dust-extinction properties for SN 2012cu to be consistent with those of the MW. Furthermore, we find no evidence for significant time variation in any of these extinction tracers. We also compare the dust extinction curve models of Cardelli et al., O'Donnell,. and Fitzpatrick, and find the predictions of Fitzpatrick fit SN 2012cu the best. Finally, the distance to NGC4772, the host of SN 2012cu, at a redshift of z = 0.0035, often assigned to the Virgo Southern Extension, is determined to be 16.6 +/- 1.1 Mpc. We compare this result with distance measurements in the literature.
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28. |
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29. |
- Bongard, E., et al.
(författare)
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Antivirals for influenza-Like Illness? A randomised Controlled trial of Clinical and Cost effectiveness in primary CarE (ALIC(4) E): the ALIC(4) E protocol
- 2018
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Ingår i: Bmj Open. - : BMJ. - 2044-6055. ; 8:7
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Tidskriftsartikel (refereegranskat)abstract
- Introduction Effective management of seasonal and pandemic influenza is a high priority internationally. Guidelines in many countries recommend antiviral treatment for older people and individuals with comorbidity at increased risk of complications. However, antivirals are not often prescribed in primary care in Europe, partly because its clinical and cost effectiveness has been insufficiently demonstrated by non-industry funded and pragmatic studies. Methods and analysis Antivirals for influenza-Like Illness? An rCt of Clinical and Cost effectiveness in primary CarE is a European multinational, multicentre, open-labelled, non-industry funded, pragmatic, adaptive-platform, randomised controlled trial. Initial trial arms will be best usual primary care and best usual primary care plus treatment with oseltamivir for 5days. We aim to recruit at least 2500 participants 1year presenting with influenza-like illness (ILI), with symptom duration 72hours in primary care over three consecutive periods of confirmed high influenza incidence. Participant outcomes will be followed up to 28 days by diary and telephone. The primary objective is to determine whether adding antiviral treatment to best usual primary care is effective in reducing time to return to usual daily activity with fever, headache and muscle ache reduced to minor severity or less. Secondary objectives include estimating cost-effectiveness, benefits in subgroups according to age (<12, 12-64 and >64 years), severity of symptoms at presentation (low, medium and high), comorbidity (yes/no), duration of symptoms (48hours/>48-72hours), complications (hospital admission and pneumonia), use of additional prescribed medication including antibiotics, use of over-the-counter medicines and self-management of ILI symptoms. Ethics and dissemination Research ethics committee (REC) approval was granted by the NRES Committee South Central (Oxford B) and Clinical Trial Authority (CTA) approval by The Medicines and Healthcare products Regulatory Agency. All participating countries gained national REC and CTA approval as required. Dissemination of results will be through peer-reviewed scientific journals and conference presentations.
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31. |
- Butler, C. C., et al.
(författare)
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Oseltamivir plus usual care versus usual care for influenza-like illness in primary care: an open-label, pragmatic, randomised controlled trial
- 2020
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Ingår i: Lancet. - : Elsevier BV. - 0140-6736. ; 395:10217, s. 42-52
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Tidskriftsartikel (refereegranskat)abstract
- Background Antivirals are infrequently prescribed in European primary care for influenza-like illness, mostly because of perceived ineffectiveness in real world primary care and because individuals who will especially benefit have not been identified in independent trials. We aimed to determine whether adding antiviral treatment to usual primary care for patients with influenza-like illness reduces time to recovery overall and in key subgroups. Methods We did an open-label, pragmatic, adaptive, randomised controlled trial of adding oseltamivir to usual care in patients aged 1 year and older presenting with influenza-like illness in primary care. The primary endpoint was time to recovery, defined as return to usual activities, with fever, headache, and muscle ache minor or absent. The trial was designed and powered to assess oseltamivir benefit overall and in 36 prespecified subgroups defined by age, comorbidity, previous symptom duration, and symptom severity, using a Bayesian piece-wise exponential primary analysis model. The trial is registered with the ISRCTN Registry, number ISRCTN 27908921. Findings Between Jan 15, 2016, and April 12, 2018, we recruited 3266 participants in 15 European countries during three seasonal influenza seasons, allocated 1629 to usual care plus oseltamivir and 1637 to usual care, and ascertained the primary outcome in 1533 (94%) and 1526 (93%). 1590 (52%) of 3059 participants had PCR-confirmed influenza infection. Time to recovery was shorter in participants randomly assigned to oseltamivir (hazard ratio 1.29, 95% Bayesian credible interval [BCrI] 1.20-1.39) overall and in 30 of the 36 prespecified subgroups, with estimated hazard ratios ranging from 1.13 to 1.72. The estimated absolute mean benefit from oseltamivir was 1.02 days (95% [BCrI] 0.74-1.31) overall, and in the prespecified subgroups, ranged from 0.70 (95% BCrI 0.30-1.20) in patients younger than 12 years, with less severe symptoms, no comorbidities, and shorter previous illness duration to 3.20 (95% BCrI 1.00-5.50) in patients aged 65 years or older who had more severe illness, comorbidities, and longer previous illness duration. Regarding harms, an increased burden of vomiting or nausea was observed in the oseltamivir group. Interpretation Primary care patients with influenza-like illness treated with oseltamivir recovered one day sooner on average than those managed by usual care alone. Older, sicker patients with comorbidities and longer previous symptom duration recovered 2-3 days sooner. Copyright (C) 2019 Elsevier Ltd. All rights reserved.
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33. |
- Li, X., et al.
(författare)
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Cost-effectiveness of adding oseltamivir to primary care for influenza-like-illness: economic evaluation alongside the randomised controlled ALIC(4)E trial in 15 European countries
- 2023
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Ingår i: European Journal of Health Economics. - : Springer Science and Business Media LLC. - 1618-7598 .- 1618-7601. ; 24:6, s. 909-922
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Tidskriftsartikel (refereegranskat)abstract
- Background Oseltamivir is usually not often prescribed (or reimbursed) for non-high-risk patients consulting for influenza-like-illness (ILI) in primary care in Europe. We aimed to evaluate the cost-effectiveness of adding oseltamivir to usual primary care in adults/adolescents (13 years +) and children with ILI during seasonal influenza epidemics, using data collected in an open-label, multi-season, randomised controlled trial of oseltamivir in 15 European countries. Methods Direct and indirect cost estimates were based on patient reported resource use and official country-specific unit costs. Health-Related Quality of Life was assessed by EQ-5D questionnaires. Costs and quality adjusted life-years (QALY) were bootstrapped (N = 10,000) to estimate incremental cost-effectiveness ratios (ICER), from both the healthcare payers' and the societal perspectives, with uncertainty expressed through probabilistic sensitivity analysis and expected value for perfect information (EVPI) analysis. Additionally, scenario (self-reported spending), comorbidities subgroup and country-specific analyses were performed. Results The healthcare payers' expected ICERs of oseltamivir were euro22,459 per QALY gained in adults/adolescents and euro13,001 in children. From the societal perspective, oseltamivir was cost-saving in adults/adolescents, but the ICER is euro8,344 in children. Large uncertainties were observed in subgroups with comorbidities, especially for children. The expected ICERs and extent of decision uncertainty varied between countries (EVPI ranged euro1-euro35 per patient). Conclusion Adding oseltamivir to primary usual care in Europe is likely to be cost-effective for treating adults/adolescents and children with ILI from the healthcare payers' perspective (if willingness-to-pay per QALY gained > euro22,459) and cost-saving in adults/adolescents from a societal perspective.
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34. |
- Ouchi, D., et al.
(författare)
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Clinical prediction of laboratory-confirmed influenza in adults with influenza-like illness in primary care. A randomized controlled trial secondary analysis in 15 European countries
- 2022
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Ingår i: Family Practice. - : Oxford University Press (OUP). - 0263-2136 .- 1460-2229. ; 39:3, s. 398-405
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Tidskriftsartikel (refereegranskat)abstract
- Lay Summary Influenza is usually diagnosed clinically. However, the accuracy of a diagnosis of influenza based on clinical features is limited because symptoms overlap considerably with those caused by other microorganisms. This study examined whether identification of the severity rather than the presence of key signs and symptoms could aid in the diagnosis of influenza, thereby helping clinicians to determine when antiviral agent use is appropriate. The authors used the database of a previous randomized clinical trial on the effectiveness of an antiviral carried out in primary care centers in 15 countries in Europe during three epidemic periods from 2015/2016 to 2017/2018. Participants with influenza symptoms were included and they were asked about the presence and severity of different symptoms during the baseline visit with their doctors and a nasopharyngeal swab was taken for microbiological analysis. Overall, only 51% of the patients aged 18 or older had a confirmed influenza infection. Clinical findings are not particularly useful for confirming or excluding the diagnosis of influenza. However, the results of our study recommend considering how intense the different symptoms are, since key symptoms rated as moderate or severe are slightly better for predicting flu rather than the presence or absence of these symptoms. Background Clinical findings do not accurately predict laboratory diagnosis of influenza. Early identification of influenza is considered useful for proper management decisions in primary care. Objective We evaluated the diagnostic value of the presence and the severity of symptoms for the diagnosis of laboratory-confirmed influenza infection among adults presenting with influenza-like illness (ILI) in primary care. Methods Secondary analysis of patients with ILI who participated in a clinical trial from 2015 to 2018 in 15 European countries. Patients rated signs and symptoms as absent, minor, moderate, or major problem. A nasopharyngeal swab was taken for microbiological identification of influenza and other microorganisms. Models were generated considering (i) the presence of individual symptoms and (ii) the severity rating of symptoms. Results A total of 2,639 patients aged 18 or older were included in the analysis. The mean age was 41.8 +/- 14.7 years, and 1,099 were men (42.1%). Influenza was microbiologically confirmed in 1,337 patients (51.1%). The area under the curve (AUC) of the model for the presence of any of seven symptoms for detecting influenza was 0.66 (95% confidence interval [CI]: 0.65-0.68), whereas the AUC of the symptom severity model, which included eight variables-cough, fever, muscle aches, sweating and/or chills, moderate to severe overall disease, age, abdominal pain, and sore throat-was 0.70 (95% CI: 0.69-0.72). Conclusion Clinical prediction of microbiologically confirmed influenza in adults with ILI is slightly more accurate when based on patient reported symptom severity than when based on the presence or absence of symptoms.
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36. |
- Verheij, T. J., et al.
(författare)
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Clinical presentation, microbiological aetiology and disease course in patients with flu-like illness: A post hoc analysis of randomised controlled trial data
- 2022
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Ingår i: British Journal of General Practice. - 0960-1643. ; 72:716
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Tidskriftsartikel (refereegranskat)abstract
- Background There is little evidence about the relationship between aetiology, illness severity, and clinical course of respiratory tract infections (RTIs) in primary care. Understanding these associations would aid in the development of effective management strategies for these infections. Aim To investigate whether clinical presentation and illness course differ between RTIs where a viral pathogen was detected and those where a potential bacterial pathogen was found. Design and setting Post hoc analysis of data from a pragmatic randomised trial on the effects of oseltamivir in patients with flu-like illness in primary care (n = 3266) in 15 European countries. Method Patient characteristics and their signs and symptoms of disease were registered at baseline. Nasopharyngeal (adults) or nasal and pharyngeal (children) swabs were taken for polymerase chain reaction analysis. Patients were followed up until 28 days after inclusion. Regression models and Kaplan-Meier curves were used to analyse the relationship between aetiology, clinical presentation at baseline, and course of disease including complications. Results Except for a less prominent congested nose (odds ratio [OR] 0.55, 95% confidence interval [CI] = 0.35 to 0.86) and acute cough (OR 0.42, 95% CI = 0.27 to 0.65) in patients with flu-like illness in whom a possible bacterial pathogen was isolated, there were no clear clinical differences in presentations between those with a possible bacterial aetiology compared with those with a viral aetiology. Also, course of disease and complications were not related to aetiology. Conclusion Given current available microbiological tests and antimicrobial treatments, and outside pandemics such as COVID-19, microbiological testing in primary care patients with flu-like illness seems to have limited value. A wait-andsee policy in most of these patients with flu-like illness seems the best option. © 2022 Royal College of General Practitioners. All rights reserved.
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38. |
- Li, X., et al.
(författare)
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Direct and Indirect Costs of Influenza-Like Illness Treated with and Without Oseltamivir in 15 European Countries: A Descriptive Analysis Alongside the Randomised Controlled ALIC(4)E Trial
- 2021
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Ingår i: Clinical Drug Investigation. - : Springer Science and Business Media LLC. - 1173-2563 .- 1179-1918. ; 41:8, s. 685-699
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Tidskriftsartikel (refereegranskat)abstract
- Background and Objective Influenza-like illness (ILI) leads to a substantial disease burden every winter in Europe; however, oseltamivir is not frequently prescribed to ILI patients in the primary-care setting. An open-label, multi-country, multi-season, randomised controlled trial investigated the effectiveness of oseltamivir for treating ILI in 15 European countries. We aimed to evaluate whether patients presenting with ILI in primary care and being managed with the addition of oseltamivir to usual care had lower average direct and indirect costs compared to patients with usual care alone. Methods Resource use data were extracted from participants' daily diaries. Itemised country-specific unit costs were collected through official tariffs, pharmacies or literature. Costs were converted to 2018 values. The null hypothesis was tested based on one-sided credible intervals (CrIs) obtained by bootstrapping. Base-case analysis estimated direct cost and productivity losses using itemised costed resource use and the human capital approach. Scenario analyses with self-reported spending rather than itemised costing were also performed. Results Patients receiving oseltamivir (N = 1306) reported fewer healthcare visits, medication uses, hospital attendances and paid-work hours lost than the other patients (N = 1298). Excluding the oseltamivir cost, the average direct costs were lower in patients treated with oseltamivir from all perspectives, but these differences were not statistically significant (perspective of patient: euro17 [0-95% Crl: 16-19] vs. euro24 [5-100% Crl: 18-29]; healthcare provider: euro37 [28-67] vs. euro44 [25-55]; healthcare payers: euro54 [45-85] vs. euro68 [45-81]; and society: euro423 [399-478] vs. euro451 [390-478]). Scenario and age-group analyses confirmed these findings, but with some between-country differences. Conclusion The average direct and indirect costs were consistently lower in patients treated with oseltamivir than in patients without from four perspectives (excluding the oseltamivir cost). However, these differences were not statistically significant.
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