| 1. |
- Bixby, H., et al.
(author)
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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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In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 569:7755, s. 260-4
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Journal article (peer-reviewed)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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| 2. |
- Blumenau, A.T., et al.
(author)
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Straight and kinked 90° partial dislocations in diamond and 3C-SiC
- 2002
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In: Journal of Physics. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 14:48, s. 12741-12747
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Journal article (peer-reviewed)abstract
- Density-functional based calculations are used to investigate low energy core structures of 90° partial dislocations in diamond and 3C-SiC. In both materials dislocation glide is analysed in terms of kink formation and migration and the fundamental steps to kink migration are investigated. We find the C terminated core structure in SiC to be more mobile than the Si core. However, the Si partial is electrically active and this opens the possibility of recombination-enhanced glide under ionizing conditions or an enhanced mobility in doped material.
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| 3. |
- Blumenau, A.T., et al.
(author)
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Structure and motion of basal dislocations in silicon carbide
- 2003
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In: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 68:17, s. 174108-1
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Journal article (peer-reviewed)abstract
- 30° and 90° Shockley partial dislocations lying in {111} and basal planes of cubic and hexagonal silicon carbide, respectively, are investigated theoretically. Density-functional-based tight-binding total-energy calculations are used to determine the core structure and energetics of the dislocations. In a second step their electronic structure is investigated using a pseudopotential method with a Gaussian basis set. Finally, the thermal activation barriers to glide motion of 30° and 90° Shockley partials are calculated in terms of a process involving the formation and migration of kinks along the dislocation line. The mechanism for enhanced dislocation movement observed under current injection conditions in bipolar silicon carbide devices is discussed.
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| 4. |
- Eberlein, T.A.G., et al.
(author)
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Alphabet luminescence lines in 4H-SiC
- 2002
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In: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 65:18
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Journal article (peer-reviewed)abstract
- First-principles density functional calculations are used to investigate antisite pairs in 4H-SiC. We show that they are likely to be formed in close proximity under ionizing conditions, and they possess a donor level and thermal stability consistent with the series of 40 photoluminescent lines called the alphabet lines. Moreover, the gap vibrational mode of the silicon antisite defect is close to a phonon replica of the b1 line and possesses a weak isotopic shift with 13C in agreement with observation.
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| 5. |
- Fall, C.J., et al.
(author)
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Electronic and vibrational properties of Mg- and O-related complexes in GaN
- 2001
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In: Materials Science & Engineering. - 0921-5107 .- 1873-4944. ; 82:1, s. 88-90
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Journal article (peer-reviewed)abstract
- We investigate from first principles the energetic and vibrational properties of various candidate structures for the 3125 cm-1 local vibrational mode in GaN, known to be related to hydrogen passivated magnesium atoms. The orientation of the electric dipole of this mode has recently been measured with respect to the wurtzite c-axis, giving a result seemingly inconsistent with current atomic models for this defect. We study the possibility that complexes of magnesium, native impurities and hydrogen could give rise to the experimental observations. Furthermore, we consider a possible candidate giving rise to a 0.88-eV line in a variety of electron-irradiated GaN samples. We find evidence that a deep donor level including substitutional oxygen must result from a complex impurity.
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| 6. |
- Goss, J.P., et al.
(author)
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Extended defects in diamond: the interstitial platelet
- 2003
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In: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 67:16, s. 165208-1
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Journal article (peer-reviewed)abstract
- The structure and properties of the {001} planar platelet in diamond are investigated using ab initio theory. We find that a carbonaceous model, based on a layer of self-interstitials, satisfies the requirements of transmission electron microscopy, infrared absorption data, and energetic considerations. The energetics of self-interstitial production during nitrogen aggregation are considered. It is found that the growth mechanism of the platelet involves a thermally activated release of vacancies from platelets. The role of vacant sites and platelet nitrogen are also investigated and it is shown that these defects embedded within the platelet could account for the observed optical activity.
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| 7. |
- Goss, J.P., et al.
(author)
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Small aggregates of interstitials and models for platelets in diamond
- 2000
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In: Journal of Physics. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 12:49, s. 10257-10261
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Journal article (peer-reviewed)abstract
- By examining the structure of small clusters of self-interstitials in diamond using local-density-functional techniques, we have developed models for the planar defects called platelets. We present the structures, energies and vibrational properties
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| 8. |
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| 9. |
- Latham, Chris D., et al.
(author)
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Calculated properties of point defects in Be-doped GaN
- 2003
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In: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 67:20, s. 205206-
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Journal article (peer-reviewed)abstract
- The properties of several point defects in hexagonal gallium nitride that can compensate beryllium shallow acceptors (BeGa) are calculated using the AIMPRO method based on local density functional theory. BeGa itself is predicted to have local vibrational modes (LVM's) very similar to magnesium acceptors. The highest frequency is about 663 cm-1. Consistent with other recent studies, we find that interstitial beryllium double donors and single-donor beryllium split interstitial pairs at gallium sites are very likely causes of compensation. The calculations predict that the split interstitial pairs possess three main LVM's at about 1041, 789, and 738 cm-1. Of these, the highest is very close to the experimental observation in Be-doped GaN. Although an oxygen donor at the nearest-neighboring site to a beryllium acceptor (BeGa-ON) is also a prime suspect among defects that are possibly responsible for compensation, its highest frequency is calculated to be about 699 cm-1 and hence is not related in any way to the observed center. Another mode for this defect is estimated to be about 523 cm-1 and is localized on the ON atom. These two vibrations of BeGa-ON are thus equivalent to those for the isolated substitutional centers perturbed by the presence of their impurity partners.
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| 10. |
- Lind, Lars, et al.
(author)
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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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In: eLife. - : eLife Sciences Publications Ltd. - 2050-084X. ; 10
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Journal article (peer-reviewed)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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