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| 2. |
- 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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| 9. |
- Bueno, AM, et al.
(författare)
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Influence of chemical bonds on the lifetime of the molecular-field-split 2p levels in H2S
- 2003
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Ingår i: Physical Review A (Atomic, Molecular and Optical Physics). - 1050-2947. ; 67, s. 22714:1-7
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Tidskriftsartikel (refereegranskat)abstract
- Different lifetime broadenings in molecular-field-split 2p core levels in H2S are predicted theoretically and are identified in an experimental investigation of the S 2p Auger electron spectrum. The measurements were performed for the transition to the vibrationally resolved X(1)A(1) ground state of H2S2+. The lifetimes of the 3e(1/2) and 5e(1/2) levels of the 2p ionized molecule are found to be 64 and 74 meV, respectively. This unambiguous determination of the lifetime difference of 10+/-1 meV is only possible as the 4e(1/2)-->X(1)A(1)(2b(1)(-2)) decay channel that overlaps the 5e(1/2)-->X(1)A(1)(2b(1)(-2)) channel is practically suppressed in Auger decay in H2S. The lifetime difference is confirmed by ab initio calculations. A theoretical analysis shows that it results from the mutual orientation of the core hole in the intermediate states and the valence electron density in the sulfur 3p orbitals. Both are strongly influenced by the chemical bond. Thus the observed effect is the direct result of a fundamental property of molecular electronic structure.
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| 10. |
- Burmeister, F, et al.
(författare)
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Nonadiabatic effects in photoelectron spectra of HCl and DCl. I. Experiment
- 2002
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Ingår i: Physical Review A (Atomic, Molecular and Optical Physics). - 1050-2947. ; 65:1
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Tidskriftsartikel (refereegranskat)abstract
- The HCl inner-valence photoelectron band at 26 eV binding energy has been recorded at high resolution. Discrete peaks arising from at least two separate vibrational progressions are superimposed on the broad continuum. Fano profiles are visible in one of the progressions. This indicates interference between superimposed electronic states, where weak avoided crossing allows two adiabatic states to couple. In the isotopic DCl molecular spectrum, the discrete lines are less pronounced, due to slower dissociation and therefore less coupling between the continuum and the bound state.
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| 11. |
- de, Brito AN, et al.
(författare)
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Femtosecond dissociation dynamics of core-excited molecular water
- 1999
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Ingår i: CHEMICAL PHYSICS LETTERS. - : ELSEVIER SCIENCE BV. - 0009-2614. ; 309:5-6, s. 377-385
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The fragmentation of the water molecule upon resonant core excitation and subsequent Auger decay has been studied by electron-ion coincidence spectroscopy. A qualitative comparison between the fragmentation patterns for H2O and D2O reveals that the anti-b
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| 13. |
- Feifel, Raimund, et al.
(författare)
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From localised to delocalised electronic states in free Ar, Kr and Xe clusters
- 2004
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Ingår i: European Physical Journal D. Atomic, Molecular, Optical and Plasma Physics. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 30:3, s. 343-351
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Tidskriftsartikel (refereegranskat)abstract
- We present new results for the inner valence levels of clusters of the three inert gases Ar, Kr and Xe based on photoelectron spectroscopy studies. The inner valence levels are compared to the localised core levels and to the delocalised outer valence levels. This comparison shows a gradual change from a relatively localised behaviour for Ar inner valence 3s, over the intermediate case of Kr inner valence 4s, to a more delocalised behaviour for Xe inner valence 5s. This change correlates well with the ratio between the orbital sizes and the interatomic distances. The Kr4s intermediate case is found to exhibit characteristics of both localised and delocalised behaviour.
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| 16. |
- Gisselbrecht, Mathieu, et al.
(författare)
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Photon energy dependence of fragmentation of small argon clusters
- 2005
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 123:19
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Tidskriftsartikel (refereegranskat)abstract
- Photofragmentation of small argon clusters with size below ten atoms is reported. In this size range significant modifications from the electronic properties and geometry take place. When tuning the photon energy through the argon 2p edge, the fragmentation pattern is changed. Specifically, cation dimer production is enhanced at the 2p(3/2)-> 4s resonance, while above the 2p edge almost complete atomization is observed. In both cases, the widths of the peaks in the mass spectra indicate that a large amount of kinetic energy is imparted to the fragment due to the formation of multiply charged clusters. A model based on "Coulomb explosion"-charge separation, simply resulting in a complete atomization of the cluster with no dependence on the photon energy-is insufficient to explain the observed photofragmentation of small clusters.
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| 17. |
- Le Guen, K, et al.
(författare)
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Development of a four-element conical electron lens dedicated to high resolution Auger electron-ion(s) coincidence experiments
- 2002
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 1089-7623 .- 0034-6748. ; 73:11, s. 3885-3894
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Tidskriftsartikel (refereegranskat)abstract
- A four-element conical electron lens has been developed in view of its integration to a double toroidal electron energy analyzer (DTA) dedicated to Auger electron-ion coincidence measurements. The lens design, using electron trajectory numerical simulations, was entirely guided by the perspective of analyzing energetic electrons with high resolution in the multicoincidence regime. The design, construction, and experimental characterization stages of this electron optics system are described in this article. Emphasis is put on the importance of third generation synchrotron radiation sources when performing such multicoincidence experiments.
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| 18. |
- Lindgren, Andreas, et al.
(författare)
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Molecular alignment of ammonia studied by electron-ion-ion coincidence spectroscopy
- 2005
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 122:11
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Tidskriftsartikel (refereegranskat)abstract
- Electron-ion-ion coincidence measurements carried out at discrete resonances near the N 1s threshold in ammonia are reported. The measured coincidence spectra show clear alignment of the molecule upon resonant core-electron excitation. The coincidence data are analyzed to extract information about the molecule in the excited state by simulating the alignment and the dissociation processes. Dynamic changes in molecular geometry are found as the photon energy is scanned through the N 1s -> 4a(1) resonance, whereas for the N 1s -> 2e state the geometry and kinetic energy released upon dissociation remain unchanged. The alignment of the core-excited molecules is found to be preserved even in two-step dissociation processes.
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| 20. |
- Miron, C, et al.
(författare)
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Mapping potential energy surfaces by core electron excitation: the resonant Auger decay spectrum of BF3
- 2002
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Ingår i: Chemical Physics Letters. - 0009-2614. ; 359:1-2, s. 48-54
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Tidskriftsartikel (refereegranskat)abstract
- High-resolution electron spectroscopy applied under resonant Auger-Raman conditions is shown to be a powerful tool for characterizing complex potential energy surfaces of core-excited states in polyatomic systems. BF3 is used as a prototype molecule: excitation of the Bls --> 2a(2)(") transition leads to an exceptional out-of-plane vibrational excitation resolved over a wide energy range (3.6 eV). The photon energy dependence of the spectra through the resonance profile is rationalized in the frame of the relative slopes of the potential energy curves along the boron out-of-plane displacement coordinate.
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| 22. |
- Mocellin, A, et al.
(författare)
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Experimental study of photoionization of ozone in the 12 to 21 eV region
- 2001
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Ingår i: JOURNAL OF CHEMICAL PHYSICS. - : AMER INST PHYSICS. - 0021-9606. ; 115:11, s. 5041-5046 Language: English
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Tidskriftsartikel (refereegranskat)abstract
- The total and partial ion yield of ozone using time-of-flight is presented. The measurements were done using multicoincidence between a photoelectron and a photoion (PEPICO). Comparison with the photoelectron spectrum and previous measurements using other
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| 23. |
- Rosenqvist, L, et al.
(författare)
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Femtosecond dissociation of ozone studied by the Auger Doppler effect
- 2001
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Ingår i: JOURNAL OF CHEMICAL PHYSICS. - : AMER INST PHYSICS. - 0021-9606. ; 115:8, s. 3614-3620 Language: English
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Tidskriftsartikel (refereegranskat)abstract
- A Doppler-type shift in the kinetic energy of atomic Auger electrons emitted after fast dissociation of O-3 molecules is observed. The resonant Auger spectrum from the decay of repulsive core-excited states reflects both the early molecular ozone decay an
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| 24. |
- Salek, P, et al.
(författare)
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Dynamical suppression of atomic peaks in resonant dissociative photoemission
- 2001
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Ingår i: CHEMICAL PHYSICS LETTERS. - : ELSEVIER SCIENCE BV. - 0009-2614. ; 343:3-4, s. 332-338 Language: English
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Tidskriftsartikel (refereegranskat)abstract
- Resonant excitation to the F1s-sigma* dissociative state in hydrogen fluoride gives a photoelectron spectrum where the spectator part contains strong atomic lines but a participator part where such lines are lacking. We demonstrate that this contrasting b
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| 25. |
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| 26. |
- Tchaplyguine, Maxim, et al.
(författare)
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Selective probing of the electronic structure of free clusters using resonant core-level spectroscopy
- 2003
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Ingår i: Chemical Physics. - 0301-0104. ; 289:1, s. 3-13
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Tidskriftsartikel (refereegranskat)abstract
- In this paper the first resonant photoemission and partial electron yield studies of free clusters are presented. The resonant photoemission spectra of free argon clusters have been recorded with excitation energies determined from the cluster X-ray absorption spectrum near the Ar 2p ionization threshold. The decay of 2p(-1)4s and 2p(-1)3d cluster surface and "bulk" excited states has been investigated in detail. The combination of resonant photoemission and partial electron yield methods has allowed a selective probing of the electronic and geometric structure, yielding new results concerning the interplay between the energy of the excited states, their orbital character and the local atomic coordination. These new results demonstrate the power of resonant core level spectroscopy when applied to free clusters, as well as the advantages of free clusters for the studies of the bulk and surface energetics of nanoscale solids. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 27. |
- Tchaplyguine, Maxim, et al.
(författare)
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The size of neutral free clusters as manifested in the relative bulk-to-surface intensity in core level photoelectron spectroscopy
- 2004
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 120:1, s. 345-356
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Tidskriftsartikel (refereegranskat)abstract
- A new approach for obtaining an estimate of the effective size of the free neutral clusters is proposed. The approach relies on an experimental measure of the surface and interior or "bulk" cluster atoms provided by the x-ray photoelectron spectroscopy and on a model for the attenuation of photoelectrons ejected from the bulk of the cluster as the result of the ionizing irradiation. The experimental part gives the ratio of the electron signal from the bulk cluster atoms to that from the cluster surface atoms for a wide range of cluster sizes and electron kinetic energies. The attenuated response of the bulk atoms is modeled using an exponential law with the cluster size and kinetic-energy-dependent electron escape depth as parameters. For the experimental size range, model-based calculations for Ar, Kr, and Xe clusters are presented. The cluster size estimates obtained from comparison of the model calculations and experimental results agree well with those determined from the parameters of the cluster creation process. The combination of experiment and modeling also makes it possible to estimate the effective escape depth for electron propagation in free clusters. For Ar, Kr, and Xe clusters of varying mean size, absolute determination of the surface and bulk electron binding energies of the core levels used in the experiments has also been made. (C) 2004 American Institute of Physics.
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| 28. |
- Wiesner, K, et al.
(författare)
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The dynamic Auger-Doppler effect in HF and DF: control of fragment velocities in femtosecond dissociation through photon energy detuning
- 2002
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Ingår i: Chemical Physics Letters. - 0009-2614. ; 354:5-6, s. 382-388
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Tidskriftsartikel (refereegranskat)abstract
- The Auger-Doppler effect in the experimental spectra of HF and DF is presented. and the dynamics of ultra-fast dissociation in the core-excited state are discussed. The Doppler splitting of the atomic Auger peak is calculated and simulated using a classical model and a very good agreement is found between experiment and simulation. It is shown that the difference in photon energy relative to the resonance is transferred completely into the kinetic energy release (KER). This is expected to be a general phenomenon, but is clearly illuminated in the HF/DF case, Thus the fragment velocity can be controlled through photon energy detuning.
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| 29. |
- Wiesner, K, et al.
(författare)
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Valence photoionization and resonant core excitation of ozone - experimental and theoretical study of the (C)over-tilde-state of O-3(+)
- 2003
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Ingår i: Chemical Physics Letters. - 0009-2614. ; 375:1-2, s. 76-83
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Tidskriftsartikel (refereegranskat)abstract
- Resonant Auger electron spectra of core excited O-3 (O(F)1s(-1) 2b(1)(1)) are presented for the first time. The photoionization valence spectrum with sample purity and resolution superior to those published is presented. The first direct experimental evidence for the (C) over tilde (2) B-1 state of O-3(+) is found. Ab initio calculations of the resonant Auger electron (RAE) spectrum have been performed supporting the assignment of the (C) over tilde -state. (C) 2003 Elsevier Science B.V. All rights reserved.
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| 30. |
- Öhrwall, Gunnar, et al.
(författare)
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The electronic structure of free water clusters probed by Auger electron spectroscopy
- 2005
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 123, s. 054310-
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Tidskriftsartikel (refereegranskat)abstract
- (H2O)(N) clusters generated in a supersonic expansion source with N similar to 1000 were core ionized by synchrotron radiation, giving rise to core-level photoelectron and Auger electron spectra (AES), free from charging effects. The AES is interpreted as being intermediate between the molecular and solid water spectra showing broadened bands as well as a significant shoulder at high kinetic energy. Qualitative considerations as well as ab initio calculations explain this shoulder to be due to delocalized final states in which the two valence holes are mostly located at different water molecules. The ab initio calculations show that valence hole configurations with both valence holes at the core-ionized water molecule are admixed to these final states and give rise to their intensity in the AES. Density-functional investigations of model systems for the doubly ionized final states-the water dimer and a 20-molecule water cluster-were performed to analyze the localization of the two valence holes in the electronic ground states. Whereas these holes are preferentially located at the same water molecule in the dimer, they are delocalized in the cluster showing a preference of the holes for surface molecules. The calculated double-ionization potential of the cluster (22.1 eV) is in reasonable agreement with the low-energy limit of the delocalized hole shoulder in the AES.
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