Photoionization Of Atomic Oxygen At The Multiplet Term Level From 20 To 212 Ev

The valence shell photoionization branching ratios of atomic oxygen are measured at the multiplet term level in a synchrotron-radiation-based electron spectrometry experiment and calculated using the multiconfiguration Hartree-Fock (MCHF) method for photon energies between 20 and 212 eV. The 2p (S-4,D-2,P-2) branching ratios, 2s P-2 to 2s P-4 intensity ratio, and 2s to 2p cross-section ratio for removal of a 2s of 2p electron are presented, and satisfactory agreement between the experiment and the MCHF calculation is found. In addition, the relative photoionization cross section is measured between 24 and 122 eV and is compared with calculations and a previous absolute cross-section measurement. Good agreement between the experimental and MCHF results is seen

Angular-Distribution Of Fluorescence From Photoionization-Produced He+ (N=2)

We report the first measurement of the angular distribution of the 304-Å He + ( n = 2 ) radiation following photoionization. This distribution reflects the alignment of the ion, which is related to the fraction ξ = σ ( 2 p , k d ) [ σ ( 2 p , k s ) + σ ( 2 p , k d ) ] of d component in the electron wave. The experimental angular distributions correspond to alignments of -0.62 ± 0.03 and -0.62 ± 0.02 at photon energies of 65.5 and 66.5 eV, respectively. These translate into ratios ξ = 0.25 ± 0.04 and 0.25 ± 0.03 , in good agreement with close-coupling calculations

Angular distributions of the atomic scandium 3d and 4s photoelectrons in the region of the 3p - \u3e 3d giant resonance

A determination of the angular distribution parameter beta of the 3d and 4s main lines of atomic scandium in the resonance region of the 3p-- \u3e nd,ms excitations has been carried out using electron spectrometry in conjunction with monochromatized synchrotron radiation., These measurements reveal strong variations of beta8 throughout the entire resonance region, highlighting the complicated nature of the ionization process for this first and seemingly simple 3d transition metal. The beta values-of the photoelectrons resulting in 4s subshell, ionization deviate significantly from 2.0 in qualitative, but not-quantitative, agreement with recent many-body perturbation-theory calculations

High-resolution photoelectron spectrometry of autoionizing resonances between the P-3 and D-1 thresholds in atomic chlorine

We present a measurement of the partial and differential photoionization cross sections for production of the fine-structure states of Cl+ P-3(J) in the region of the (3)p(41)Dnl (l = 0,2) autoionizing resonances. All series of resonances show distinctive behavior for the J=2 to J=1 cross-section ratio. The angular distribution parameter beta was also measured for the two principal ionic states (J = 1,2). The behavior of beta is very similar for both J=1,2 channels, except at the LS-forbidden nd(2)S resonance series, where the J=2 channel shows a pronounced dip that indicates an important contribution from the parity-unfavored epsilon d photoelectron waves. The widths of the 4d(2)S, 6s(2)D, and 7s(2)D resonances were measured and the results are compared with available theoretical calculations

Direct probe of Mott-Hubbard to charge-transfer insulator transition and electronic structure evolution in transition-metal systems

We report the most direct experimental verification of Mott-Hubbard and charge-transfer insulators through x-ray emission spectroscopy in transition-metal (TM) fluorides. The p-d hybridization features in the spectra allow a straightforward energy alignment of the anion-2p and metal-3d valence states, which visually shows the difference between the two types of insulators. Furthermore, in parallel with the theoretical Zaanen-Sawatzky-Allen diagram, a complete experimental systematics of the 3d Coulomb interaction and the 2p-3d charge-transfer energy is reported and could serve as a universal experimental trend for other TM systems including oxides

Detection and Molecular Diversity of Cryptosporidium spp. and Giardia duodenalis in the Endangered Iberian Lynx (Lynx pardinus), Spain

Cryptosporidium spp. and Giardia duodenalis are the main non-viral causes of diarrhoea in humans and domestic animals globally. Comparatively, much less information is currently available in free-ranging carnivore species in general and in the endangered Iberian lynx (Lynx pardinus) in particular. Cryptosporidium spp. and G. duodenalis were investigated with molecular (PCR and Sanger sequencing) methods in individual faecal DNA samples of free-ranging and captive Iberian lynxes from the main population nuclei in Spain. Overall, Cryptosporidium spp. and G. duodenalis were detected in 2.4% (6/251) and 27.9% (70/251) of the animals examined, respectively. Positive animals to at least one of them were detected in each of the analysed population nuclei. The analysis of partial ssu rRNA gene sequences revealed the presence of rodent-adapted C. alticolis (n = 1) and C. occultus (n = 1), leporid-adapted C. cuniculus (n = 2), and zoonotic C. parvum (n = 2) within Cryptosporidium, and zoonotic assemblages A (n = 5) and B (n = 3) within G. duodenalis. Subgenotyping analyses allowed for the identification of genotype VaA19 in C. cuniculus (gp60 locus) and sub-assemblages AI and BIII/BIV in G. duodenalis (gdh, bg, and tpi loci). This study represents the first molecular description of Cryptosporidium spp. and G. duodenalis in the Iberian lynx in Spain. The presence of rodent/leporid-adapted Cryptosporidium species in the surveyed animals suggests spurious infections associated to the Iberian lynx's diet. The Iberian lynx seems a suitable host for zoonotic genetic variants of Cryptosporidium (C. parvum) and G. duodenalis (assemblages A and B), although the potential risk of human transmission is regarded as limited due to light parasite burdens and suspected low excretion of infective (oo)cysts to the environment by infected animals. More research should be conducted to ascertain the true impact of these protozoan parasites in the health status of the endangered Iberian lynx.This article is based upon work from project LIFE 19NAT/ES001055 LYNXCONNECT ‘Creating a genetically and demographically functional Iberian Lynx (Lynx pardinus) metapopulation (2020–2025)’ supported by the European Commission. J.C.-G. was supported by the Centre for Biomedical Research Network (CB21/13/00083), Health Institute Carlos III, Ministry of Science and Innovation and European Union-Next Generation EU. S.C.-S. was supported by an FPU grant (FPU19/06026) funded by the Spanish Ministry of Universities. D.J.-M. holds a PhD contract granted by Own Research Plan of the University of Córdoba. D.G.-B. is the recipient of a Sara Borrell research contract (CD19CIII/00011) funded by the Spanish Ministry of Science, Innovation and Universities. A.D. is the recipient of a PFIS contract (FI20CIII/00002) funded by the Spanish Ministry of Science, Innovation and Universities. We thank all the veterinarians and animal keepers of ex situ and in situ conservation programs involved in the sampling as well as all the members of the CAD centre for their assistance in the collection of samples and epidemiological information. We also gratefully acknowledge Junta de Andalucía and Junta de Comunidades de Castilla-La Mancha.S

Motor skill learning in the middle-aged: limited development of motor chunks and explicit sequence knowledge

The present study examined whether middle-aged participants, like young adults, learn movement patterns by preparing and executing integrated sequence representations (i.e., motor chunks) that eliminate the need for external guidance of individual movements. Twenty-four middle-aged participants (aged 55–62) practiced two fixed key press sequences, one including three and one including six key presses in the discrete sequence production task. Their performance was compared with that of 24 young adults (aged 18–28). In the middle-aged participants motor chunks as well as explicit sequence knowledge appeared to be less developed than in the young adults. This held especially with respect to the unstructured 6-key sequences in which most middle-aged did not develop independence of the key-specific stimuli and learning seems to have been based on associative learning. These results are in line with the notion that sequence learning involves several mechanisms and that aging affects the relative contribution of these mechanisms

Evidence For The Spin-Orbit-Induced [Formula Presented] Resonances In Atomic Br And Cl

Evidence is presented for the occurrence of the [Formula Presented]-forbidden [Formula Presented] autoionization resonances in both Br and Cl by a measurement of the photoelectrons associated with the [Formula Presented]-resolved [Formula Presented] final ionic states. Effects of spin-orbit coupling are delineated at the [Formula Presented]-term level for both the [Formula Presented] and the [Formula Presented] resonances, and differences for these spin-orbit-induced pathways are highlighted. © 1996 The American Physical Society