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1.
  • Kanai, M, et al. (author)
  • 2023
  • swepub:Mat__t
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2.
  • Niemi, MEK, et al. (author)
  • 2021
  • swepub:Mat__t
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5.
  • Lichtenberg, Elinor M., et al. (author)
  • A global synthesis of the effects of diversified farming systems on arthropod diversity within fields and across agricultural landscapes
  • 2017
  • In: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 23:11, s. 4946-4957
  • Journal article (peer-reviewed)abstract
    • Agricultural intensification is a leading cause of global biodiversity loss, which can reduce the provisioning of ecosystem services in managed ecosystems. Organic farming and plant diversification are farm management schemes that may mitigate potential ecological harm by increasing species richness and boosting related ecosystem services to agroecosystems. What remains unclear is the extent to which farm management schemes affect biodiversity components other than species richness, and whether impacts differ across spatial scales and landscape contexts. Using a global metadataset, we quantified the effects of organic farming and plant diversification on abundance, local diversity (communities within fields), and regional diversity (communities across fields) of arthropod pollinators, predators, herbivores, and detritivores. Both organic farming and higher in-field plant diversity enhanced arthropod abundance, particularly for rare taxa. This resulted in increased richness but decreased evenness. While these responses were stronger at local relative to regional scales, richness and abundance increased at both scales, and richness on farms embedded in complex relative to simple landscapes. Overall, both organic farming and in-field plant diversification exerted the strongest effects on pollinators and predators, suggesting these management schemes can facilitate ecosystem service providers without augmenting herbivore (pest) populations. Our results suggest that organic farming and plant diversification promote diverse arthropod metacommunities that may provide temporal and spatial stability of ecosystem service provisioning. Conserving diverse plant and arthropod communities in farming systems therefore requires sustainable practices that operate both within fields and across landscapes.
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6.
  • Woodcock, B. A., et al. (author)
  • Meta-analysis reveals that pollinator functional diversity and abundance enhance crop pollination and yield
  • 2019
  • In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10:1
  • Journal article (peer-reviewed)abstract
    • How insects promote crop pollination remains poorly understood in terms of the contribution of functional trait differences between species. We used meta-analyses to test for correlations between community abundance, species richness and functional trait metrics with oilseed rape yield, a globally important crop. While overall abundance is consistently important in predicting yield, functional divergence between species traits also showed a positive correlation. This result supports the complementarity hypothesis that pollination function is maintained by non-overlapping trait distributions. In artificially constructed communities (mesocosms), species richness is positively correlated with yield, although this effect is not seen under field conditions. As traits of the dominant species do not predict yield above that attributed to the effect of abundance alone, we find no evidence in support of the mass ratio hypothesis. Management practices increasing not just pollinator abundance, but also functional divergence, could benefit oilseed rape agriculture.
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8.
  • Burney, P., et al. (author)
  • A case-control study of the relation between plasma selenium and asthma in European populations : a GAL2EN project
  • 2008
  • In: Allergy. European Journal of Allergy and Clinical Immunology. - : Wiley. - 0105-4538 .- 1398-9995. ; 63:7, s. 865-871
  • Journal article (peer-reviewed)abstract
    • BACKGROUND: There is evidence that selenium levels are relatively low in Europe and may be falling. Low levels of selenium or low activity of some of the enzymes dependent on selenium have been associated with asthma. METHODS: The GA(2)LEN network has organized a multicentre case-control study in Europe to assess the relation of plasma selenium to asthma. The network compared 569 cases in 14 European centres with a diagnosis of asthma and reporting asthma symptoms in the last 12 months with 576 controls from the same centres with no diagnosis of asthma and no asthmatic symptoms in the last 12 months. RESULTS: All cases and controls were selected from the same population defined by age and place of residence. Mean plasma selenium concentrations among the controls ranged from 116.3 microg/l in Palermo to 67.7 microg/l in Vienna and 56.1 microg/l among the children in Oslo. Random effects meta-analysis of the results from the centres showed no overall association between asthma and plasma selenium [odds ratio (OR)/10 microg/l increase in plasma selenium: 1.04; 95% confidence interval (CI): 0.89-1.21] though there was a significantly protective effect in Lodz (OR: 0.48; 95% CI: 0.29-0.78) and a marginally significant adverse effect in Amsterdam (OR: 1.68; 95% CI: 0.98-2.90) and Ghent (OR: 1.35; 95% CI: 1.03-1.77). CONCLUSION: This study does not support a role for selenium in protection against asthma, but effect modification and confounding cannot be ruled out.
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10.
  • Hammen, V. C., et al. (author)
  • Establishment of a cross-European field site network in the ALARM project for assessing large-scale changes in biodiversity
  • 2010
  • In: Environmental Monitoring & Assessment. - : Springer Science and Business Media LLC. - 1573-2959 .- 0167-6369. ; 164:1-4, s. 337-348
  • Journal article (peer-reviewed)abstract
    • The field site network (FSN) plays a central role in conducting joint research within all Assessing Large-scale Risks for biodiversity with tested Methods (ALARM) modules and provides a mechanism for integrating research on different topics in ALARM on the same site for measuring multiple impacts on biodiversity. The network covers most European climates and biogeographic regions, from Mediterranean through central European and boreal to subarctic. The project links databases with the European-wide field site network FSN, including geographic information system (GIS)-based information to characterise the test location for ALARM researchers for joint on-site research. Maps are provided in a standardised way and merged with other site-specific information. The application of GIS for these field sites and the information management promotes the use of the FSN for research and to disseminate the results. We conclude that ALARM FSN sites together with other research sites in Europe jointly could be used as a future backbone for research proposals.
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11.
  • Holland, D. M. P., et al. (author)
  • A study of the valence shell electronic structure and photoionisation dynamics of ortho-dichlorobenzene, ortho-bromochlorobenzene and trichlorobenzene
  • 2015
  • In: Chemical Physics. - : Elsevier BV. - 0301-0104 .- 1873-4421. ; 448, s. 61-75
  • Journal article (peer-reviewed)abstract
    • The valence shell electronic structure and photoionisation dynamics of ortho-dichlorobenzene, ortho-bromochlorobenzene and trichlorobenzene have been investigated both experimentally and theoretically. Angle resolved photoelectron spectra of ortho-dichlorobenzene have been recorded using synchrotron radiation in the photon energy range from close to threshold to 100 eV. The photoelectron anisotropy parameters derived from these spectra have been compared to predicted values obtained with the continuum multiple scattering approach. The comparison demonstrates that ionisation from some of the orbitals is influenced by the Cooper minimum associated with the chlorine atom. High resolution photoelectron spectra of the outer valence orbitals of ortho-dichlorobenzene and ortho-bromochlorobenzene have been recorded with HeI radiation and the observed structure has been interpreted using calculated ionisation energies and spectral intensities. Electron correlation affects ionisation of the inner valence orbitals and leads to satellite formation. Simulations of the (X) over tilde B-2(1), (A) over tilde (2)A(2) and (B) over tilde B-2(2) state photoelectron bands in ortho-dichlorobenzene have enabled most of the vibrational progressions appearing in the experimental spectrum to be assigned. Photoelectron spectra of trichlorobenzene have also been measured and the anisotropy parameters associated with some of the outer valence orbitals exhibit a photon energy dependence which resembles that predicted for atomic chlorine. This behaviour is consistent with the theoretically predicted character of these orbitals.
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12.
  • Holland, D. M. P., et al. (author)
  • A study of the valence shell electronic structure of the 5-halouracils
  • 2008
  • In: Chemical Physics. - : Elsevier BV. - 0301-0104 .- 1873-4421. ; 352:1-3, s. 205-216
  • Journal article (peer-reviewed)abstract
    • Valence shell photoelectron spectra of the 5-halouracils have been recorded using synchrotron radiation at photon energies of 40 and 80 eV. Photoelectron angular distributions have been determined and these provide an experimental means of deducing the extent to which the molecular orbitals possess predominantly sigma, pi or halogen np character. In chloro-, bromo- and iodouracil two peaks, associated with the essentially halogen atom lone-pair orbitals, have been observed. The separation between these peaks, and the value of their photoelectron asymmetry parameters at an excitation energy of 40 eV, are compared with results for the corresponding orbitals in the halobenzenes and halothiophenes. Vertical ionisation energies and spectral intensities have been evaluated using the many-body Green's function approach, thereby enabling theoretical spectra to be derived. Assignments have been proposed for most of the structure observed in the valence shell photoelectron spectra based upon the available experimental and theoretical evidence.
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13.
  • Holland, D. M. P., et al. (author)
  • A study of the valence shell electronic structure of uracil and the methyluracils
  • 2008
  • In: Chemical Physics. - : Elsevier BV. - 0301-0104 .- 1873-4421. ; 353:1-3, s. 47-58
  • Journal article (peer-reviewed)abstract
    • The valence shell photoelectron spectra of uracil, 1-methyluracil and 6-methyluracil have been studied experimentally and theoretically. Synchrotron radiation has been used to record spectra at photon energies of 40 and 80 eV. Photoelectron angular distributions have been determined and these provide an experimental means of distinguishing between sigma- and pi-type orbitals. Vertical ionization energies and spectral intensities have been evaluated using the many-body Green's function approach, thereby enabling theoretical photoelectron spectra to be derived. The calculated spectra display a satisfactory agreement with the experimental data and this has allowed most of the photoelectron bands to be assigned. Two of the outer-valence vertical ionization energies are similar to one another and the vibrational progressions associated with these transitions overlap strongly. Vibronic interaction between these states, induced through the excitation of out-of-plane vibrational modes, may lead to nonadiabatic effects. Preliminary theoretical investigation of this interaction has been performed.
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14.
  • Holland, D. M. P., et al. (author)
  • An experimental and theoretical study of the valence shell photoelectron spectra of 2-chloropyridine and 3-chloropyridine
  • 2017
  • In: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 147:16
  • Journal article (peer-reviewed)abstract
    • The valence shell photoelectron spectra of 2-chloropyridine and 3-chloropyridine have been studied both experimentally and theoretically. Synchrotron radiation has been employed to record angle resolved photoelectron spectra in the photon energy range 20-100 eV, and these have enabled anisotropy parameters and branching ratios to be derived. The experimental results have been compared with theoretical predictions obtained using the continuum multiple scattering X alpha approach. This comparison shows that the anisotropy parameter associated with the nominally chlorine lone-pair orbital lying in the molecular plane is strongly affected by the atomic Cooper minimum. In contrast, the photoionization dynamics of the second lone-pair orbital, orientated perpendicular to the molecular plane, seem relatively unaffected by this atomic phenomenon. The outer valence ionization has been studied theoretically using the third-order algebraic-diagrammatic construction (ADC(3)) approximation scheme for the one-particle Green's function, the outer valence Green's function method, and the equation-of-motion (EOM) coupled cluster (CC) theory at the level of the EOM-IP-CCSD and EOM-EE-CC3 models. The convergence of the results to the complete basis set limit has been investigated. The ADC(3) method has been employed to compute the complete valence shell ionization spectra of 2-chloropyridine and 3-chloropyridine. The relaxation mechanism for ionization of the nitrogen sigma-type lone-pair orbital (sigma(N) (LP)) has been found to be different to that for the corresponding chlorine lone-pair (sigma(Cl) (LP)). For the sigma(N) (LP) orbital, pi-pi* excitations play the main role in the screening of the lone-pair hole. In contrast, excitations localized at the chlorine site involving the chlorine pi(Cl) (LP) lone-pair and the Cl 4p Rydberg orbital are the most important for the sigma(Cl) (LP) orbital. The calculated photoelectron spectra have allowed assignments to be proposed for most of the structure observed in the experimental spectra. The theoretical work also highlights the formation of satellite states, due to the breakdown of the single particle model of ionization, in the inner valence region.
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15.
  • Holland, D. M. P., et al. (author)
  • An experimental and theoretical study of the valence shell photoelectron spectrum of bromochlorofluoromethane
  • 2010
  • In: Journal of Physics B. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 43:13, s. 135101-
  • Journal article (peer-reviewed)abstract
    • The complete valence shell photoelectron spectrum of bromochlorofluoromethane (CHFClBr), covering the binding energy range similar to 10-50 eV, has been recorded using synchrotron radiation and the observed structure has been interpreted using ionization energies and relative spectral intensities computed using the third-order algebraic-diagrammatic-construction (ADC(3)) scheme for the one-particle Green's function and the outer valence Green's function (OVGF) method. The theoretical results demonstrate that the inner valence region of the photoelectron spectrum is dominated by satellite structure. Angle-resolved photoelectron spectra, recorded at selected excitation energies, have enabled the orbital assignments for the outer valence bands to be confirmed. The four outermost photoelectron bands, ascribed to the two pairs of orbitals associated with the nominally chlorine and bromine lone-pairs, exhibit characteristic angular distributions. The photon energy dependent variations in the relative photoelectron band intensities provide additional support for the orbital assignments.
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17.
  • Meziane, El Kahina, et al. (author)
  • Bi-Functional Chicken Immunoglobulin-Like Receptors With a Single Extracellular Domain (ChIR-AB1): Potential Framework Genes Among a Relatively Stable Number of Genes Per Haplotype
  • 2019
  • In: Frontiers in Immunology. - : FRONTIERS MEDIA SA. - 1664-3224. ; 10
  • Journal article (peer-reviewed)abstract
    • The leukocyte receptor complex (LRC) in humans encodes many receptors with immunoglobulin-like (Ig-like) extracellular domains, including the killer Ig-like receptors (KIRs) expressed on natural killer (NK) cells among others, the leukocyte Ig-like receptors (LILRs) expressed on myeloid and B cells, and an Fc receptor (FcR), all of which have important roles in the immune response. These highly-related genes encode activating receptors with positively-charged residues in the transmembrane region, inhibitory receptors with immuno-tyrosine based motifs (ITIMs) in the cytoplasmic tail, and bi-functional receptors with both. The related chicken Ig-like receptors (ChIRs) are almost all found together on a microchromosome, with over 100 activating (A), inhibitory (B), and bi-functional (AB) genes, bearing either one or two extracellular Ig-like domains, interspersed over 500-1,000 kB in the genome of an individual chicken. Sequencing studies have suggested rapid divergence and little overlap between ChIR haplotypes, so we wished to begin to understand their genetics. We chose to use a hybridization technique, reference strand-mediated conformational analysis (RSCA), to examine the ChIR-AB1 family, with a moderate number of genes dispersed across the microchromosome. Using fluorescently-labeled references (FLR), we found that RSCA and sequencing of ChIR-AB1 extracellular exon gave two groups of peaks with mobility correlated with sequence relationship to the FLR. We used this system to examine widely-used and well-characterized experimental chicken lines, finding only one or a few simple ChIR haplotypes for each line, with similar numbers of peaks overall. We found much more complicated patterns from a broiler line from a commercial breeder and a flock of red junglefowl, but trios of parents and offspring from another commercial chicken line show that the complicated patterns are due to heterozygosity, indicating a relatively stable number of peaks within haplotypes of these birds. Some ChIR-AB1 peaks were found in all individuals from the commercial lines, and some of these were shared with red junglefowl and the experimental lines derived originally from egg-laying chickens. Overall, this analysis suggests that there are some simple features underlying the apparent complexity of the ChIR locus.
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19.
  • Potts, A. W., et al. (author)
  • A study of the valence shell electronic structure and photoionisation dynamics of meta-dichlorobenzene and meta-bromochlorobenzene
  • 2013
  • In: Chemical Physics. - : Elsevier BV. - 0301-0104 .- 1873-4421. ; 415, s. 84-97
  • Journal article (peer-reviewed)abstract
    • A combined experimental and theoretical investigation has been performed to study the valence shell electronic structure and photoionisation dynamics of meta-dichlorobenzene and meta-bromochlorobenzene. Angle resolved photoelectron spectra of meta-dichlorobenzene have been recorded using synchrotron radiation in the photon energy range from close to threshold to 100 eV. These have enabled photoelectron anisotropy parameters and branching ratios to be derived. The continuum multiple scattering approach has been employed to calculate photoionisation partial cross-sections and photoelectron angular distributions of the outer valence orbitals of meta-dichlorobenzene. A comparison between the corresponding experimental and theoretical results has demonstrated that ionisation from some of the orbitals is influenced by the Cooper minimum associated with the chlorine atom. Ionisation energies and spectral intensities evaluated with the third-order algebraic diagrammatic construction approximation for the one-particle Green's function and the outer valence Green's function approaches have allowed the features observed in the complete valence shell photoelectron spectra of meta-dichlorobenzene and meta-bromochlorobenzene to be interpreted. Many-body phenomena strongly influence ionisation from the inner valence orbitals and lead to the intensity associated with a particular orbital being redistributed amongst numerous satellites. High resolution photoelectron spectra have been recorded with HeI radiation. Vibrational structure has been observed in some of the photoelectron bands and tentative assignments have been proposed. 
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21.
  • Powis, I., et al. (author)
  • A study of the valence shell electronic structure and photoionisation dynamics of para-dichlorobenzene and para-bromochlorobenzene
  • 2013
  • In: Chemical Physics. - : Elsevier BV. - 0301-0104 .- 1873-4421. ; 415, s. 291-308
  • Journal article (peer-reviewed)abstract
    • The valence shell electronic structure and photoionisation dynamics of para-dichlorobenzene and para-bromochlorobenzene have been investigated both experimentally and theoretically. High resolution photoelectron spectra of the outer valence orbitals have been recorded with HeI radiation and the observed structure has been interpreted using calculated ionisation energies and spectral intensities. The theoretical predictions for the single-hole ionic states due to outer valence ionisation agree satisfactorily with the experimental results. Ionisation from the inner valence orbitals is strongly influenced by many-body effects and the with a particular orbital is spread amongst numerous satellites. Some of the photoelectron bands exhibit vibrational progressions and tentative assignments have been proposed. The photoionisation dynamics of the outer valence orbitals of para-dichlorobenzene have been investigated theoretically by using the continuum multiple scattering approach to calculate photoionisation partial cross-sections and photoelectron anisotropy parameters. The results show that ionisation from some of the orbitals is affected by the Cooper minimum associated with the chlorine atom. Synchrotron radiation has been used to record angle resolved photoelectron spectra of the entire valence shell, for photon energies between threshold and similar to 100 eV, and these have allowed the corresponding experimental data to be derived. A comparison between the predicted and measured anisotropy parameters confirms the influence of the Cooper minimum in those orbitals related to the chlorine lone-pairs.
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22.
  • Powis, I., et al. (author)
  • A study of the valence shell electronic structure and photoionization dynamics of selenophene
  • 2007
  • In: Journal of Physics B. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 40:11, s. 2019-2041
  • Journal article (peer-reviewed)abstract
    • The photoelectron spectrum of selenophene has been recorded using synchrotron radiation in the photon energy range 20-80 eV and the inner valence region has been studied in detail for the first time. Green's function methods have been employed to evaluate the energies and spectral intensities of all valence shell ionization transitions and the results have facilitated an interpretation of the experimental spectra. Strong configuration interaction results in a redistribution of the intensity associated with the low lying pi(1)( 1b(1)) orbital amongst several satellite states located in the outer valence region. The continuum multiple scattering approach has been used to calculate photoelectron asymmetry parameters for selenophene, thiophene and hydrogen sulphide, and these theoretical predictions have been compared with the corresponding experimental data to assess the influence of Cooper minima and shape resonances. The comparison indicates that the Se 4p and the S 3p Cooper minima have little effect on the valence shell photoionization dynamics of selenophene and thiophene, respectively. This outcome is discussed in connection with the closely related hydrogen selenide and hydrogen sulphide molecules where strong resonant phenomena are observed.
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24.
  • Shaheen, S., et al. (author)
  • The relation between paracetamol use and asthma : a GA2LEN European case-control study
  • 2008
  • In: European Respiratory Journal. - : European Respiratory Society (ERS). - 0903-1936 .- 1399-3003. ; 32:5, s. 1231-1236
  • Journal article (peer-reviewed)abstract
    • Studies from the UK and USA suggest that frequent use of paracetamol (acetaminophen) may increase the risk of asthma, but data across Europe are lacking. As part of a multicentric case-control study organised by the Global Allergy and Asthma European Network (GA(2)LEN), it was examined whether or not frequent paracetamol use is associated with adult asthma across Europe. The network compared 521 cases with a diagnosis of asthma and reporting of asthma symptoms within the last 12 months with 507 controls with no diagnosis of asthma and no asthmatic symptoms within the last 12 months across 12 European centres. All cases and controls were selected from the same population, defined by age (20-45 yrs) and place of residence. In a random effects meta-analysis, weekly use of paracetamol, compared with less frequent use, was strongly positively associated with asthma after controlling for confounders. There was no evidence for heterogeneity across centres. No association was seen between use of other analgesics and asthma. These data add to the increasing and consistent epidemiological evidence implicating frequent paracetamol use in asthma in diverse populations.
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25.
  • Trofimov, A. B., et al. (author)
  • Ionization of pyridine : Interplay of orbital relaxation and electron correlation
  • 2017
  • In: Journal of Chemical Physics. - : AMER INST PHYSICS. - 0021-9606 .- 1089-7690. ; 146:24
  • Journal article (peer-reviewed)abstract
    • The valence shell ionization spectrum of pyridine was studied using the third-order algebraic-diagrammatic construction approximation scheme for the one-particle Green's function and the outer-valence Green's function method. The results were used to interpret angle resolved photoelectron spectra recorded with synchrotron radiation in the photon energy range of 17-120 eV. The lowest four states of the pyridine radical cation, namely, (2)A(2)(1a(2)(-1)), (2)A(1)(7a(1)(-1)), B-2(1)(2b(1)(-1)), and B-2(2)(5b(2)(-1)), were studied in detail using various high-level electronic structure calculation methods. The vertical ionization energies were established using the equation-of-motion coupled-cluster approach with single, double, and triple excitations (EOM-IP-CCSDT) and the complete basis set extrapolation technique. Further interpretation of the electronic structure results was accomplished using Dyson orbitals, electron density difference plots, and a second-order perturbation theory treatment for the relaxation energy. Strong orbital relaxation and electron correlation effects were shown to accompany ionization of the 7a1 orbital, which formally represents the nonbonding sigma-type nitrogen lone-pair (n sigma) orbital. The theoretical work establishes the important roles of the pi-system (pi-pi* excitations) in the screening of the n sigma-hole and of the relaxation of the molecular orbitals in the formation of the 7a(1)(n sigma)(-1) state. Equilibrium geometric parameters were computed using the MP2 (second-order Moller-Plesset perturbation theory) and CCSD methods, and the harmonic vibrational frequencies were obtained at the MP2 level of theory for the lowest three cation states. The results were used to estimate the adiabatic 0-0 ionization energies, which were then compared to the available experimental and theoretical data. Photoelectron anisotropy parameters and photoionization partial cross sections, derived from the experimental spectra, were compared to predictions obtained with the continuum multiple scattering approach.
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30.
  • Coriani, S., et al. (author)
  • A study of the valence shell electronic structure and photoionisation dynamics of s-triazine
  • 2015
  • In: Chemical Physics. - : Elsevier BV. - 0301-0104 .- 1873-4421. ; 450, s. 115-124
  • Journal article (peer-reviewed)abstract
    • A joint experimental and theoretical approach has been used to study the valence shell electronic structure and photoionisation dynamics of s-triazine (1,3,5-triazine). Synchrotron radiation has been employed to record angle resolved photoelectron spectra of the complete valence shell for photon energies between 17.5 and 100 eV, thereby allowing photoelectron anisotropy parameters and branching ratios to be determined. Absolute photoionisation partial cross sections have been estimated as the product of these branching ratios and the absolute photoabsorption cross section. The Kohn-Sham and the time-dependent version of density functional theory methods have been used to calculate photoelectron anisotropy parameters and photoionisation partial cross sections, and these have been compared with the corresponding experimental data. The calculations predict that shape resonances affect the photoionisation dynamics of several of the molecular orbitals. The angle resolved photoelectron spectra suggest that the 1a(2)''(pi) orbital is more tightly bound than the 5e'(sigma) orbital, and that the 4a(1)'(sigma) orbital is more tightly bound than the 1a(2)'(sigma) orbital, in agreement with the predicted molecular orbital sequence. For the outer valence orbitals the single-particle picture of ionisation holds but electron correlation becomes increasingly important for the inner valence 4e', 3e' and 3a(1)' orbitals and leads to a redistribution of intensity. Instead of a readily distinguishable main-line, associated with each of these orbitals, the photoelectron intensity is spread over numerous satellite states and the resulting band is broad and featureless. 
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31.
  • Decleva, P., et al. (author)
  • Perfluoro effects in the occupied and virtual valence orbitals of hexafluorobenzene
  • 2007
  • In: Journal of Physics B. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 40:14, s. 2939-2959
  • Journal article (peer-reviewed)abstract
    • The complete valence shell photoelectron spectrum of hexafluorobenzene has been recorded with synchrotron radiation and the observed structure has been interpreted using ab initio ionization energies and relative spectral intensities. The theoretical predictions for the single-hole ionic states due to outer valence shell ionization agree satisfactorily with the experimental results. Ionization from the inner valence, essential F 2s, orbitals is strongly influenced by many-body effects and the intensity is spread amongst numerous satellites. Photoelectron angular distributions and branching ratios have been determined both experimentally and theoretically, and demonstrate that shape resonances affect the valence shell photoionization dynamics. Some of the shape resonances have been associated with virtual valence orbitals. An assessment of the perfluoro effect on the occupied and virtual valence orbitals of hexafluorobenzene has been carried out by comparing the present results for C6F6 with similar data for C6H6.
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32.
  • Groeneveld, Jeroen, et al. (author)
  • Australian shelf sediments reveal shifts in Miocene Southern Hemisphere westerlies
  • 2017
  • In: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 3:5
  • Journal article (peer-reviewed)abstract
    • Global climate underwent a major reorganization when the Antarctic ice sheet expanded ~14 million years ago (Ma) (1). This event affected global atmospheric circulation, including the strength and position of the westerlies and the Intertropical Convergence Zone (ITCZ), and, therefore, precipitation patterns (2–5). We present new shallow-marine sediment records from the continental shelf of Australia (International Ocean Discovery Program Sites U1459 and U1464) providing the first empirical evidence linking high-latitude cooling around Antarctica to climate change in the (sub)tropics during the Miocene. We show that Western Australia was arid during most of the Middle Miocene. Southwest Australia became wetter during the Late Miocene, creating a climate gradient with the arid interior, whereas northwest Australia remained arid throughout. Precipitation and river runoff in southwest Australia gradually increased from 12 to 8 Ma, which we relate to a northward migration or intensification of the westerlies possibly due to increased sea ice in the Southern Ocean (5). Abrupt aridification indicates that the westerlies shifted back to a position south of Australia after 8 Ma. Our midlatitude Southern Hemisphere data are consistent with the inference that expansion of sea ice around Antarctica resulted in a northward movement of the westerlies. In turn, this may have pushed tropical atmospheric circulation and the ITCZ northward, shifting the main precipitation belt over large parts of Southeast Asia (4).
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33.
  • Holder, Peter E., et al. (author)
  • Preparing for a changing future in recreational fisheries : 100 research questions for global consideration emerging from a horizon scan
  • 2020
  • In: Reviews in Fish Biology and Fisheries. - : Springer Science and Business Media LLC. - 0960-3166 .- 1573-5184. ; 30:1, s. 137-151
  • Research review (peer-reviewed)abstract
    • Recreational fisheries hold immense ecological, social, and economic value. The management of these fisheries is increasingly important as we move forward in the Anthropocene. Recreational fisheries managers face several challenges as fisheries often involve diverse social and ecological systems comprised of complex feedback and stakeholder motivations and needs. Here, we used a horizon scanning exercise to yield 100 research questions related to recreational fisheries science and management in the Anthropocene. Initial research questions (n = 205) were collected from recreational fisheries experts (i.e., stakeholders, managers, researchers) from various sectors (i.e., industry, government, NGOs) and geographic locations (14 countries: Australia, Brazil, Canada, Czech Republic, Germany, Italy, New Zealand, Norway, South Africa, Spain, Sweden, Switzerland, United Kingdom, USA). These questions were subsequently categorized, thematized, and refined by our authorship team, eventually yielding what we considered to be the top 100 research questions of relevance to management of recreational fisheries. The key themes include: human dimensions; bioeconomics; resource monitoring and data acquisition; governance; management-regulatory actions; management-stock and habitat enhancement; catch-and-release; impacts of recreational fisheries on populations, communities and ecosystems; threats and sustainability; and angler outreach, education and engagement. It is our intention that this comprehensive and forward-looking list will create a framework to guide future research within this field, and contribute to evidence-based recreational fisheries management and policy.
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34.
  • Holland, D. M. P., et al. (author)
  • A study of the valence shell photoionisation dynamics of pyrimidine and pyrazine
  • 2011
  • In: Chemical Physics. - : Elsevier BV. - 0301-0104 .- 1873-4421. ; 390:1, s. 25-35
  • Journal article (peer-reviewed)abstract
    • The complete valence shell photoelectron spectra of pyrimidine and pyrazine have been recorded with synchrotron radiation and the observed structure has been interpreted with the aid of vertical ionisation energies and relative spectral intensities calculated using time-dependent density functional theory. The theoretical predictions for the single-hole ionic states due to outer valence shell ionisation agree satisfactorily with the experimental results. Ionisation from the inner valence orbitals is strongly influenced by many-body effects and the intensity associated with a particular orbital is spread amongst numerous satellites. Photoelectron angular distributions and partial cross sections have been determined both experimentally and theoretically, and demonstrate that shape resonances affect the valence shell photoionisation dynamics. In addition to shape resonances occurring a few eV above the ionisation threshold, the calculations indicate that many of the orbitals are influenced by shape resonant processes at much higher energies. Some of these higher energy resonances have been confirmed through a comparison between the relevant theoretical and experimental photoelectron asymmetry parameters. The spectral behaviour of asymmetry parameters associated with pi-orbitals has been shown to differ from that of asymmetry parameters associated with sigma-orbitals. These differences provide a means of distinguishing between the two types of orbitals even in heavily congested regions of the photoelectron spectrum suffering from band overlap.
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35.
  • Obaseki, D., et al. (author)
  • The relation of airway obstruction to asthma, chronic rhinosinusitis and age: results from a population survey of adults
  • 2014
  • In: Allergy. - : Wiley. - 0105-4538 .- 1398-9995. ; 69:9, s. 1205-1214
  • Journal article (peer-reviewed)abstract
    • Rationale: There is conflicting evidence on whether patients with asthma experience an accelerated decline in lung function with age. We examined the association between postbronchodilator lung function, asthma, chronic rhinosinusitis (CRS), and atopy with age using a large European sample. Methods: In 17 centers in 11 European countries, case control studies were nested within representative cross-sectional surveys of adults aged less than 75 years. Representative samples of participants with asthma, CRS or both and controls were assessed for postbronchodilator ventilatory function, smoking history, atopy, and treatment. Multiple regression was used to assess the interactive effects of age and diagnostic group on decline in postbronchodilator ventilatory function. Results: A total of 3337 participants provided adequate data (778 with asthma, 399 with CRS, 244 with both asthma and CRS and 1916 controls who had neither asthma nor CRS). Participants with asthma had lower FEV1/FVC (-4.09% (95% CI: -5.02, -3.15, P < 0.001) and a steeper slope of FEV1/FVC against age (-0.14%/annum [95%CI: -0.19, -0.08]) equivalent to smoking 1-2 packs of cigarettes per day. Those with atopy had a slope equivalent to controls. Conclusions: People with asthma have a steeper decline in postbronchodilator lung function with age, but neither CRS nor atopy alone were associated with such decline.
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36.
  • Pecl, Gretta T., et al. (author)
  • Climate-driven 'species-on-the-move' provide tangible anchors to engage the public on climate change
  • 2023
  • In: People and Nature. - : John Wiley & Sons. - 2575-8314. ; 5:5, s. 1384-1402
  • Journal article (peer-reviewed)abstract
    • Over recent decades, our understanding of climate change has accelerated greatly, but unfortunately, observable impacts have increased in tandem. Both mitigation and adaptation have not progressed at the level or scale warranted by our collective knowledge on climate change. More effective approaches to engage people on current and future anthropogenic climate change effects are urgently needed. Here, we show how species whose distributions are shifting in response to climate change, that is, ‘species-on-the-move’, present an opportunity to engage people with climate change by linking to human values, and our deep connections with the places in which we live, in a locally relevant yet globally coherent narrative. Species-on-the-move can impact ecosystem structure and function, food security, human health, livelihoods, culture and even the climate itself through feedback to the climate system, presenting a wide variety of potential pathways for people to understand that climate change affects them personally as individuals. Citizen science focussed on documenting changes in biodiversity is one approach to foster a deeper engagement on climate change. However, other possible avenues, which may offer potential to engage people currently unconnected with nature, include arts, games or collaborations with rural agriculture (e.g. new occurrences of pest species) or fisheries organisations (e.g. shifting stocks) or healthcare providers (e.g. changing distributions of disease vectors). Through the importance we place on the aspects of life impacted by the redistribution of species around us, species-on-the-move offer emotional pathways to connect with people on the complex issue of climate change in profound ways that have the potential to engender interest and action on climate change. Read the free Plain Language Summary for this article on the Journal blog.
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37.
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38.
  • Schliep, Klaus, et al. (author)
  • Intertwining phylogenetic trees and networks
  • 2017
  • In: Methods in Ecology and Evolution. - 2041-210X. ; 8:10, s. 1212-1220
  • Journal article (peer-reviewed)abstract
    • 1. The fields of phylogenetic tree and network inference have dramatically advanced in the past decade, but independently with few attempts to bridge them.2. Here we provide a framework, implemented in the phangorn library in R, to transfer information between trees and networks.3. This includes: (i) identifying and labelling equivalent tree branches and network edges, (ii) transferring tree branch support to network edges, and (iii) mapping bipartition support from a sample of trees (e.g. from bootstrapping or Bayesian inference) onto network edges.4. ability to readily combine tree and network information should lead to more comprehensive evolutionary comparisons and inferences.
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