| 1. |
- Gurung, Rejina, et al.
(författare)
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Predictors for timely initiation of breastfeeding after birth in the hospitals of Nepal- a prospective observational study.
- 2021
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Ingår i: International breastfeeding journal. - : Springer Science and Business Media LLC. - 1746-4358. ; 16:1
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Tidskriftsartikel (refereegranskat)abstract
- Timely initiation of breastfeeding can reduce neonatal morbidities and mortality. We aimed to study predictors for timely initiation of breastfeeding (within 1 h of birth) among neonates born in hospitals of Nepal.A prospective observational study was conducted in four public hospitals between July and October 2018. All women admitted in the hospital for childbirth and who consented were included in the study. An independent researchers observed whether the neonates were placed in skin-to-skin contact, delay cord clamping and timely initiation of breastfeeding. Sociodemographic variables, obstetric and neonate information were extracted from the maternity register. We analysed predictors for timely initiation of breastfeeding with Pearson chi-square test and multivariate logistic regression.Among the 6488 woman-infant pair observed, breastfeeding was timely initiated in 49.5% neonates. The timely initiation of breastfeeding was found to be higher among neonates who were placed skin-to-skin contact (34.9% vs 19.9%, p - value < 0.001). The timely initiation of breastfeeding was higher if the cord clamping was delayed than early cord clamped neonates (44.5% vs 35.3%, p - value < 0.001). In multivariate analysis, a mother with no obstetric complication during admission had 57% higher odds of timely initiation of breastfeeding (aOR 1.57; 95% CI 1.33, 1.86). Multiparity was associated with less timely initiation of breastfeeding (aOR 1.56; 95% CI 1.35, 1.82). Similarly, there was more common practice of timely initiation of breastfeeding among low birthweight neonates (aOR 1.46; 95% CI 1.21, 1.76). Neonates who were placed skin-to-skin contact with mother had more than two-fold higher odds of timely breastfeeding (aOR 2.52; 95% CI 2.19, 2.89). Likewise, neonates who had their cord intact for 3 min had 37% higher odds of timely breastfeeding (aOR 1.37; 95% CI 1.21, 1.55).The rate of timely initiation of breastfeeding practice is low in the health facilities of Nepal. Multiparity, no obstetric complication at admission, neonates placed in skin-to-skin contact and delay cord clamping were strong predictors for timely initiation of breastfeeding. Quality improvement intervention can improve skin-to-skin contact, delayed cord clamping and timely initiation of breastfeeding.
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| 2. |
- Backman, John, et al.
(författare)
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On Aethalometer measurement uncertainties and an instrument correction factor for the Arctic
- 2017
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Ingår i: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 10:12, s. 5039-5062
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Tidskriftsartikel (refereegranskat)abstract
- Several types of filter-based instruments are used to estimate aerosol light absorption coefficients. Two significant results are presented based on Aethalometer measurements at six Arctic stations from 2012 to 2014. First, an alternative method of post-processing the Aethalometer data is presented, which reduces measurement noise and lowers the detection limit of the instrument more effectively than box-car averaging. The biggest benefit of this approach can be achieved if instrument drift is minimised. Moreover, by using an attenuation threshold criterion for data post-processing, the relative uncertainty from the electronic noise of the instrument is kept constant. This approach results in a time series with a variable collection time (Delta t) but with a constant relative uncertainty with regard to electronic noise in the instrument. An additional advantage of this method is that the detection limit of the instrument will be lowered at small aerosol concentrations at the expense of temporal resolution, whereas there is little to no loss in temporal resolution at high aerosol concentrations (>2.1-6.7Mm(-1) as measured by the Aethalometers). At high aerosol concentrations, minimising the detection limit of the instrument is less critical. Additionally, utilising co-located filter-based absorption photometers, a correction factor is presented for the Arctic that can be used in Aethalometer corrections available in literature. The correction factor of 3.45 was calculated for low-elevation Arctic stations. This correction factor harmonises Aethalometer attenuation coefficients with light absorption coefficients as measured by the co-located light absorption photometers. Using one correction factor for Arctic Aethalometers has the advantage that measurements between stations become more inter-comparable.
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| 3. |
- Boyer, Matthew, et al.
(författare)
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A full year of aerosol size distribution data from the central Arctic under an extreme positive Arctic Oscillation : insights from the Multidisciplinarydrifting Observatory for the Study of Arctic Climate (MOSAiC) expedition
- 2023
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Ingår i: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 23:1, s. 389-415
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Tidskriftsartikel (refereegranskat)abstract
- The Arctic environment is rapidly changing due to accelerated warming in the region. The warming trend is driving a decline in sea ice extent, which thereby enhances feedback loops in the surface energy budget in the Arctic. Arctic aerosols play an important role in the radiative balance and hence the climate response in the region, yet direct observations of aerosols over the Arctic Ocean are limited. In this study, we investigate the annual cycle in the aerosol particle number size distribution (PNSD), particle number concentration (PNC), and black carbon (BC) mass concentration in the central Arctic during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. This is the first continuous, year-long data set of aerosol PNSD ever collected over the sea ice in the central Arctic Ocean. We use a k-means cluster analysis, FLEXPART simulations, and inverse modeling to evaluate seasonal patterns and the influence of different source regions on the Arctic aerosol population. Furthermore, we compare the aerosol observations to land-based sites across the Arctic, using both long-term measurements and observations during the year of the MOSAiC expedition (2019–2020), to investigate interannual variability and to give context to the aerosol characteristics from within the central Arctic. Our analysis identifies that, overall, the central Arctic exhibits typical seasonal patterns of aerosols, including anthropogenic influence from Arctic haze in winter and secondary aerosol processes in summer. The seasonal pattern corresponds to the global radiation, surface air temperature, and timing of sea ice melting/freezing, which drive changes in transport patterns and secondary aerosol processes. In winter, the Norilsk region in Russia/Siberia was the dominant source of Arctic haze signals in the PNSD and BC observations, which contributed to higher accumulation-mode PNC and BC mass concentrations in the central Arctic than at land-based observatories. We also show that the wintertime Arctic Oscillation (AO) phenomenon, which was reported to achieve a record-breaking positive phase during January–March 2020, explains the unusual timing and magnitude of Arctic haze across the Arctic region compared to longer-term observations. In summer, the aerosol PNCs of the nucleation and Aitken modes are enhanced; however, concentrations were notably lower in the central Arctic over the ice pack than at land-based sites further south. The analysis presented herein provides a current snapshot of Arctic aerosol processes in an environment that is characterized by rapid changes, which will be crucial for improving climate model predictions, understanding linkages between different environmental processes, and investigating the impacts of climate change in future Arctic aerosol studies.
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| 4. |
- Collaud Coen, Martine, et al.
(författare)
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Multidecadal trend analysis of in situ aerosol radiative properties around the world
- 2020
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Ingår i: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 20:14, s. 8867-8908
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Tidskriftsartikel (refereegranskat)abstract
- In order to assess the evolution of aerosol parameters affecting climate change, a long-term trend analysis of aerosol optical properties was performed on time series from 52 stations situated across five continents. The time series of measured scattering, backscattering and absorption coefficients as well as the derived single scattering albedo, backscattering fraction, scattering and absorption Angstrom exponents covered at least 10 years and up to 40 years for some stations. The non-parametric seasonal Mann-Kendall (MK) statistical test associated with several pre-whitening methods and with Sen's slope was used as the main trend analysis method. Comparisons with general least mean square associated with autoregressive bootstrap (GLS/ARB) and with standard least mean square analysis (LMS) enabled confirmation of the detected MK statistically significant trends and the assessment of advantages and limitations of each method. Currently, scattering and backscattering coefficient trends are mostly decreasing in Europe and North America and are not statistically significant in Asia, while polar stations exhibit a mix of increasing and decreasing trends. A few increasing trends are also found at some stations in North America and Australia. Absorption coefficient time series also exhibit primarily decreasing trends. For single scattering albedo, 52 % of the sites exhibit statistically significant positive trends, mostly in Asia, eastern/northern Europe and the Arctic, 22 % of sites exhibit statistically significant negative trends, mostly in central Europe and central North America, while the remaining 26 % of sites have trends which are not statistically significant. In addition to evaluating trends for the overall time series, the evolution of the trends in sequential 10-year segments was also analyzed. For scattering and backscattering, statistically significant increasing 10-year trends are primarily found for earlier periods (10-year trends ending in 2010-2015) for polar stations and Mauna Loa. For most of the stations, the present-day statistically significant decreasing 10-year trends of the single scattering albedo were preceded by not statistically significant and statistically significant increasing 10-year trends. The effect of air pollution abatement policies in continental North America is very obvious in the 10-year trends of the scattering coefficient - there is a shift to statistically significant negative trends in 2009-2012 for all stations in the eastern and central USA. This long-term trend analysis of aerosol radiative properties with a broad spatial coverage provides insight into potential aerosol effects on climate changes.
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| 5. |
- Gurung, Rejina, et al.
(författare)
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The burden of adolescent motherhood and health consequences in Nepal.
- 2020
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Ingår i: BMC pregnancy and childbirth. - : Springer Science and Business Media LLC. - 1471-2393. ; 20:1
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Tidskriftsartikel (refereegranskat)abstract
- Annually, 18 million babies are born to mothers 18 years or less. Two thirds of these births take place in South Asia and Sub-Saharan Africa. Due to social and biological factors, adolescent mothers have a higher risk of adverse birth outcomes. We conducted this study to assess the incidence, risk factors, maternal and neonatal health consequences among adolescent mothers.We conducted an observational study in 12 hospitals of Nepal for a period of 12 months. Patient medical record and semi-structured interviews were used to collect demographic information of mothers, intrapartum care and outcomes. The risks of adverse birth outcomes among adolescent compared to adult mothers were assessed using multivariate logistic regression.During the study period, among the total 60,742 deliveries, 7.8% were adolescent mothers. Two third of the adolescent mothers were from disadvantaged ethnic groups, compared to half of adult mothers (66.1% vs 47.8%, p-value< 0.001). One third of the adolescent mothers did not have formal education, while one in nine adult mothers did not have formal education (32.6% vs 14.2%, p-value< 0.001). Compared to adult mothers, adolescent mothers had higher odds of experiencing prolonged labour (aOR-1.56, 95% CI, 1.17-2.10, p-0.003), preterm birth (aOR-1.40, 95% CI, 1.26-1.55, p < 0.001) and of having a baby being small for gestational age (aOR-1.38, 95% CI 1.25-1.52, p < 0.001). The odds of major malformation increased by more than two-fold in adolescent mothers compared to adult mothers (aOR-2.66, 95% CI 1.12-6.33, p-0.027).Women from disadvantaged ethnic group have higher risk of being pregnant during adolescent age. Adolescent mothers were more likely to have prolonged labour, a preterm birth, small for gestational age baby and major congenital malformation. Special attention to this high-risk group during pregnancy, labour and delivery is critical.
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| 6. |
- Kimel, Alexey, et al.
(författare)
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The 2022 magneto-optics roadmap
- 2022
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Ingår i: Journal of Physics D. - : Institute of Physics (IOP). - 0022-3727 .- 1361-6463. ; 55:46
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Tidskriftsartikel (refereegranskat)abstract
- Magneto-optical (MO) effects, viz. magnetically induced changes in light intensity or polarization upon reflection from or transmission through a magnetic sample, were discovered over a century and a half ago. Initially they played a crucially relevant role in unveiling the fundamentals of electromagnetism and quantum mechanics. A more broad-based relevance and wide-spread use of MO methods, however, remained quite limited until the 1960s due to a lack of suitable, reliable and easy-to-operate light sources. The advent of Laser technology and the availability of other novel light sources led to an enormous expansion of MO measurement techniques and applications that continues to this day (see section 1). The here-assembled roadmap article is intended to provide a meaningful survey over many of the most relevant recent developments, advances, and emerging research directions in a rather condensed form, so that readers can easily access a significant overview about this very dynamic research field. While light source technology and other experimental developments were crucial in the establishment of today's magneto-optics, progress also relies on an ever-increasing theoretical understanding of MO effects from a quantum mechanical perspective (see section 2), as well as using electromagnetic theory and modelling approaches (see section 3) to enable quantitatively reliable predictions for ever more complex materials, metamaterials, and device geometries. The latest advances in established MO methodologies and especially the utilization of the MO Kerr effect (MOKE) are presented in sections 4 (MOKE spectroscopy), 5 (higher order MOKE effects), 6 (MOKE microscopy), 8 (high sensitivity MOKE), 9 (generalized MO ellipsometry), and 20 (Cotton–Mouton effect in two-dimensional materials). In addition, MO effects are now being investigated and utilized in spectral ranges, to which they originally seemed completely foreign, as those of synchrotron radiation x-rays (see section 14 on three-dimensional magnetic characterization and section 16 on light beams carrying orbital angular momentum) and, very recently, the terahertz (THz) regime (see section 18 on THz MOKE and section 19 on THz ellipsometry for electron paramagnetic resonance detection). Magneto-optics also demonstrates its strength in a unique way when combined with femtosecond laser pulses (see section 10 on ultrafast MOKE and section 15 on magneto-optics using x-ray free electron lasers), facilitating the very active field of time-resolved MO spectroscopy that enables investigations of phenomena like spin relaxation of non-equilibrium photoexcited carriers, transient modifications of ferromagnetic order, and photo-induced dynamic phase transitions, to name a few. Recent progress in nanoscience and nanotechnology, which is intimately linked to the achieved impressive ability to reliably fabricate materials and functional structures at the nanoscale, now enables the exploitation of strongly enhanced MO effects induced by light–matter interaction at the nanoscale (see section 12 on magnetoplasmonics and section 13 on MO metasurfaces). MO effects are also at the very heart of powerful magnetic characterization techniques like Brillouin light scattering and time-resolved pump-probe measurements for the study of spin waves (see section 7), their interactions with acoustic waves (see section 11), and ultra-sensitive magnetic field sensing applications based on nitrogen-vacancy centres in diamond (see section 17). Despite our best attempt to represent the field of magneto-optics accurately and do justice to all its novel developments and its diversity, the research area is so extensive and active that there remains great latitude in deciding what to include in an article of this sort, which in turn means that some areas might not be adequately represented here. However, we feel that the 20 sections that form this 2022 magneto-optics roadmap article, each written by experts in the field and addressing a specific subject on only two pages, provide an accurate snapshot of where this research field stands today. Correspondingly, it should act as a valuable reference point and guideline for emerging research directions in modern magneto-optics, as well as illustrate the directions this research field might take in the foreseeable future.
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| 7. |
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| 8. |
- Laj, Paolo, et al.
(författare)
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A global analysis of climate-relevant aerosol properties retrieved from the network of Global Atmosphere Watch (GAW) near-surface observatories
- 2020
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Ingår i: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 13:8, s. 4353-4392
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Tidskriftsartikel (refereegranskat)abstract
- Aerosol particles are essential constituents of the Earth's atmosphere, impacting the earth radiation balance directly by scattering and absorbing solar radiation, and indirectly by acting as cloud condensation nuclei. In contrast to most greenhouse gases, aerosol particles have short atmospheric residence times, resulting in a highly heterogeneous distribution in space and time. There is a clear need to document this variability at regional scale through observations involving, in particular, the in situ near-surface segment of the atmospheric observation system. This paper will provide the widest effort so far to document variability of climate-relevant in situ aerosol properties (namely wavelength dependent particle light scattering and absorption coefficients, particle number concentration and particle number size distribution) from all sites connected to the Global Atmosphere Watch network. High-quality data from almost 90 stations worldwide have been collected and controlled for quality and are reported for a reference year in 2017, providing a very extended and robust view of the variability of these variables worldwide. The range of variability observed worldwide for light scattering and absorption coefficients, single-scattering albedo, and particle number concentration are presented together with preliminary information on their long-term trends and comparison with model simulation for the different stations. The scope of the present paper is also to provide the necessary suite of information, including data provision procedures, quality control and analysis, data policy, and usage of the ground-based aerosol measurement network. It delivers to users of the World Data Centre on Aerosol, the required confidence in data products in the form of a fully characterized value chain, including uncertainty estimation and requirements for contributing to the global climate monitoring system.
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| 9. |
- Lejaeghere, Kurt, et al.
(författare)
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Reproducibility in density functional theory calculations of solids.
- 2016
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 351:6280, s. 1415-1422
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Tidskriftsartikel (refereegranskat)abstract
- The widespread popularity of density functional theory has given rise to an extensive range of dedicated codes for predicting molecular and crystalline properties. However, each code implements the formalism in a different way, raising questions about the reproducibility of such predictions. We report the results of a community-wide effort that compared 15 solid-state codes, using 40 different potentials or basis set types, to assess the quality of the Perdew-Burke-Ernzerhof equations of state for 71 elemental crystals. We conclude that predictions from recent codes and pseudopotentials agree very well, with pairwise differences that are comparable to those between different high-precision experiments. Older methods, however, have less precise agreement. Our benchmark provides a framework for users and developers to document the precision of new applications and methodological improvements.
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| 10. |
- Nordström, Erik, et al.
(författare)
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Hyperfine parameters of η'-Cu6Sn5 and Li2CuSn
- 2001
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Ingår i: Hyperfine Interactions. - 0304-3843 .- 1572-9540. ; 136-137:3-8, s. 555-560
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Tidskriftsartikel (refereegranskat)abstract
- η′-Cu6Sn5, a suggested anode material in Li-ion batteries, has been studied by 119Sn Mössbauer spectroscopy together with the lithiated phase Li2CuSn. Full-potential electronic structure calculations were carried out using full potential LAPW (linearized augmented plane wave) within the local density approximation. The calculated hyperfine parameters, isomer shift and electric quadrupole splitting, were compared to the experimental. In presence of more than one Sn-site, the theoretical values provide a good starting guess to fit a single Mössbauer absorption peak to different sites.
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