295 research outputs found
Determining the Electron-Phonon Coupling Strength in Correlated Electron Systems from Resonant Inelastic X-ray Scattering
We show that high resolution Resonant Inelastic X-ray Scattering (RIXS)
provides direct, element-specific and momentum-resolved information on the
electron-phonon (e-p) coupling strength. Our theoretical analysis demonstrates
that the e-p coupling can be extracted from RIXS spectra by determining the
differential phonon scattering cross section. An alternative, very direct
manner to extract the coupling is to use the one and two-phonon loss ratio,
which is governed by the e-p coupling strength and the core-hole life-time.
This allows measurement of the e-p coupling on an absolute energy scale.Comment: 4 pages, 3 figure
Fragility of ferromagnetic double exchange interactions and pressure tuning of magnetism in 3d-5d double perovskite Sr2FeOsO6
FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOThe ability to tune exchange (magnetic) interactions between 3d transition metals in perovskite structures has proven to be a powerful route to discovery of novel properties. Here we demonstrate that the introduction of 3d-5d exchange pathways in double perovskites enables additional tunability, a result of the large spatial extent of 5d wave functions. Using x-ray probes of magnetism and structure at high pressure, we show that compression of Sr2FeOsO6 drives an unexpected continuous change in the sign of Fe-Os exchange interactions and a transition from antiferromagnetic to ferrimagnetic order. We analyze the relevant electron-electron interactions, shedding light into fundamental differences with the more thoroughly studied 3d-3d systems.The ability to tune exchange (magnetic) interactions between 3d transition metals in perovskite structures has proven to be a powerful route to discovery of novel properties. Here we demonstrate that the introduction of 3d-5d exchange pathways in double perovskites enables additional tunability, a result of the large spatial extent of 5d wave functions. Using x-ray probes of magnetism and structure at high pressure, we show that compression of Sr2FeOsO6 drives an unexpected continuous change in the sign of Fe-Os exchange interactions and a transition from antiferromagnetic to ferrimagnetic order. We analyze the relevant electron-electron interactions, shedding light into fundamental differences with the more thoroughly studied 3d-3d systems.912317FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO2013/14338-3Work at Argonne is supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. L.S.I.V. is supported by FAPESP (SP-Brazil) under Contract No. 2013/14338-3. M.v.V. was supported by DOE-BES under Grant No. DE-FG02-03ER46097. This research was supported in part by the World Premier International Research Center of the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan, the Japan Society for the Promotion of Science (JSPS) through a Grant-in-Aid for Scientific Research (25289233). We would like to thank Changyong Park and Curtis Kenney-Benson for their assistance at 16-BM-D beamline, Sergey N. Tkachev for assistance with gas loading, and Richard Rosenberg for help with soft x-ray measurements. We also thank GSECARS for use of the gas loading and laser drilling facilities
Bulk screening in core level photoemission from Mott-Hubbard and Charge-Transfer systems
We report bulk-sensitive hard X-ray ( = 5.95 KeV) core level
photoemission spectroscopy (PES) of single crystal VCrO
and the high- cuprate BiSrCaCuO (Bi2212).
VCrO exhibits low binding energy "satellites" to the V
"main lines" in the metallic phase, which are suppressed in the
antiferromagnetic insulator phase. In contrast, the Cu spectra of Bi2212
do not show temperature dependent features, but a comparison with soft X-ray
PES indicates a large increase in the "satellites" or weight
in the bulk. Cluster model calculations, including full multiplet structure and
a screening channel derived from the coherent band at the Fermi energy, give
very satisfactory agreement with experiments
Assessment of documented adherence to critical actions in paediatric emergency care at a district-level public hospital in South Africa
CITATION: Berends, E. A., et al. 2021. Assessment of documented adherence to critical actions in paediatric emergency care at a district-level public hospital in South Africa. African Journal of Emergency Medicine, 11(1):98-104, doi:10.1016/j.afjem.2020.09.001.The original publication is available at https://www.sciencedirect.com/journal/african-journal-of-emergency-medicineIntroduction
The provision of high-quality care is vital to improve child health and survival rates. A simple, practice-based tool was recently developed to evaluate the quality of paediatric emergency care in resource-limited settings in Africa. This study used the practice-based tool to describe the documented adherence to critical actions in paediatric emergency care at an urban district-level hospital in South Africa and assess its relation to clinical outcomes.
Methods
This study is a retrospective observational study covering a 19-month period (September 2017 to March 2019). Patients <13 years old, presenting to the emergency centre with one of six sentinel presentations (seizure, altered mental status, diarrhoea, fever, respiratory distress and polytrauma) were eligible for inclusion. In the patients' files, critical actions specific for each presentation were checked for completion. Post-hoc, a seventh group ‘multiple diagnoses’ was created for patients with more than one sentinel disease. The action completion rate was tested for association with clinical outcomes.
Results
In total, 388 patients were included (median age 1.1 years, IQR 0.3–3.6). The action completion rate varied from 63% (polytrauma) to 90% (respiratory distress). Participants with ≥75% action completion rate were younger (p < 0.001), presented with high acuity (p < 0.001), were more likely to be admitted (adjusted OR 2.2, 95%CI: 1.2–4.1), and had a hospital stay ≥4 days (adjusted OR 3.4, 95%CI: 1.5–7.9).
Conclusion
A high completion rate was associated with young age, a high patient acuity, hospital admission, length of hospital stay ≥4 days, and the specific sentinel presentation. Future research should determine whether or not documented care corresponds with the quality of delivered care and the predictive value regarding clinical outcome.https://www.sciencedirect.com/science/article/pii/S2211419X20300987?via%3DihubPublisher’s versio
Vps3 and Vps8 control integrin trafficking from early to recycling endosomes and regulate integrin-dependent functions
Recycling endosomes maintain plasma membrane homeostasis and are important for cell polarity, migration, and cytokinesis. Yet, the molecular machineries that drive endocytic recycling remain largely unclear. The CORVET complex is a multi-subunit tether required for fusion between early endosomes. Here we show that the CORVET-specific subunits Vps3 and Vps8 also regulate vesicular transport from early to recycling endosomes. Vps3 and Vps8 localise to Rab4-positive recycling vesicles and co-localise with the CHEVI complex on Rab11-positive recycling endosomes. Depletion of Vps3 or Vps8 does not affect transferrin recycling, but delays the delivery of internalised integrins to recycling endosomes and their subsequent return to the plasma membrane. Consequently, Vps3/8 depletion results in defects in integrin-dependent cell adhesion and spreading, focal adhesion formation, and cell migration. These data reveal a role for Vps3 and Vps8 in a specialised recycling pathway important for integrin trafficking
Influence of Combination Therapy with Immune Modulators on Anti-TNF Trough Levels and Antibodies in Patients with IBD
Cellular mechanisms in basic and clinical gastroenterology and hepatolog
Sr2Ir1-xRhxO4(x < 0.5): an inhomogeneous j(eff)=1/2 Hubbard system
Sem informaçãoIn a combined experimental and theoretical study, we investigate the properties of Sr2Ir1-xRhxO4. From the branching ratios of the L-edge isotropic x-ray absorption spectra, we determine that the spin-orbit coupling is remarkably independent of x for both iridium and rhodium sites. DFT + U calculations show that the doping is close to isoelectronic and introduces impurity bands of predominantly rhodium character close to the lower Hubbard band. Overlap of these two bands leads to metallic behavior. Since the low-energy states for x < 0.5 have predominantly j(eff) = 1/2 character, we suggest that the electronic properties of this material can be described by an inhomogeneous Hubbard model, where the on-site energies change due to local variations in the spin-orbit interaction strength combined with additional changes in binding energy.In a combined experimental and theoretical study, we investigate the properties of Sr2Ir1-xRhxO4. From the branching ratios of the L-edge isotropic x-ray absorption spectra, we determine that the spin-orbit coupling is remarkably independent of x for both iridium and rhodium sites. DFT + U calculations show that the doping is close to isoelectronic and introduces impurity bands of predominantly rhodium character close to the lower Hubbard band. Overlap of these two bands leads to metallic behavior. Since the low-energy states for x < 0.5 have predominantly j(eff) = 1/2 character, we suggest that the electronic properties of this material can be described by an inhomogeneous Hubbard model, where the on-site energies change due to local variations in the spin-orbit interaction strength combined with additional changes in binding energy.92815Sem informaçãoSem informaçãoSem informaçãoWork at Argonne National Laboratory was supported by the US DOE, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. M.v.V. was supported by the US Department of Energy (DOE), Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award No. DE-FG02-03ER46097 and NIU's Institute for Nanoscience, Engineering, and Technology. The computational work was partially performed at NERSC, which is supported by the US DOE Contract No. DE-AC02-05CH11231. Computational resources were partly supported by the National Institute of Supercomputing and Networking/Korea Institute of Science and Technology Information with supercomputing resources including technical support (Grant No. KSC-2013-C2-23). J.H.S. and M.J.H were supported by Basic Science Research Program through NRF (2014R1A1A2057202) and by Samsung Advanced Institute of Technology (SAIT). H.-S.K. was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (Grant No. 2013R1A6A3A01064947). The work at the University of Kentucky was supported by NSF via Grant No. DMR-1265162
Shared decision making in cancer treatment: a Dutch national survey on patients' preferences and perceptions
Objective: Shared decision making (SDM) for cancer treatment yields positive results. However, it appears that discussing essential topics for SDM is not fully integrated into treatment decision making yet. Therefore, we aim to explore to what extent discussion of therapy options, treatment consequences, and personal priorities is preferred and perceived by (former) cancer patients.Methods: An online questionnaire was distributed by the Dutch Federation of Cancer Patient Organisations among (former) cancer patients in 2018.Results: Among 3785 (former) cancer patients, 3254 patients (86%) had discussed treatments with their health care provider (HCP) and were included for analysis. Mean age was 62.1 +/- 11.5; 55% were female. Discussing the option to choose no (further) treatment was rated by 2751 (84.5%) as very important (median score 9/10-IQR 8-10). Its occurrence was perceived by 28% (N = 899), and short- and long-term treatment consequences were discussed in 81% (N = 2626) and 53% (N = 1727), respectively. An unmet wish to discuss short- and long-term consequences was reported by 22% and 26%, respectively. Less than half of the (former) cancer patients perceived that personal priorities (44%) and future plans (34%) were discussed.Conclusion: In the perception of (former) cancer patients, several essential elements for effective SDM are insufficiently discussed during cancer treatment decision making.Analysis and support of clinical decision makin
Sr\u3csub\u3e2\u3c/sub\u3eIr\u3csub\u3e1−\u3cem\u3ex\u3c/em\u3e\u3c/sub\u3eRh\u3csub\u3e\u3cem\u3ex\u3c/em\u3e\u3c/sub\u3eO\u3csub\u3e4\u3c/sub\u3e(x\u3c0.5): An Inhomogeneous \u3cem\u3ej\u3c/em\u3e\u3csub\u3eeff\u3c/sub\u3e=1/2 Hubbard system
In a combined experimental and theoretical study, we investigate the properties of Sr2Ir1−xRhxO4. From the branching ratios of the L-edge isotropic x-ray absorption spectra, we determine that the spin-orbit coupling is remarkably independent of x for both iridium and rhodium sites. DFT+U calculations show that the doping is close to isoelectronic and introduces impurity bands of predominantly rhodium character close to the lower Hubbard band. Overlap of these two bands leads to metallic behavior. Since the low-energy states for xjeff=1/2 character, we suggest that the electronic properties of this material can be described by an inhomogeneous Hubbard model, where the on-site energies change due to local variations in the spin-orbit interaction strength combined with additional changes in binding energy
INTERLAYER COUPLING AND THE METAL-INSULATOR TRANSITION IN Pr-SUBSTITUTED Bi(2)Sr(2)CaCu(2)O(8+y)
Substitution of rare-earth ions for Ca in Bi2Sr2CaCu2O8+y is known to cause a
metal-insulator transition. Using resonant photoemission we study how this
chemical substitution affects the electronic structure of the material. For the
partial Cu-density of states at E_F and in the region of the valence band we
observe no significant difference between a pure superconducting sample and an
insulating sample with 60% Pr for Ca. This suggests that the states responsible
for superconductivity are predomi- nately O-states. The partial Pr-4f density
of states was extracted utilizing the Super- Koster-Kronig Pr 4d-4f resonance.
It consists of a single peak at 1.36eV binding energy. The peak shows a
strongly assymetric Doniach-Sunjic line- shape indicating the presence of a
continuum of electronic states with sharp cut off at E_F even in this
insulating sample. This finding excludes a bandgap in the insulating sample and
supports the existance of a mobility gap caused by spatial localization of the
carriers. The presence of such carriers at the Pr-site, between the CuO_2
planes shows that the electronic structure is not purely 2-dimensional but that
there is a finite interlayer coupling. The resonance enhancement of the
photoemission cross section, at the Pr-4d threshold, was studied for the Pr-4f
and for Cu-states. Both the Pr-4f and the Cu-states show a Fano-like resonance.
This resonance of Cu-states with Pr-states is another indication of coupling
between the the Pr-states and those in the CuO_2 plane. Because of the
statistical distribution of the Pr-ions this coupling leads to a non-periodic
potential for the states in the CuO_2 plane which can lead to localization and
thus to the observed metal-insulator transition.Comment: Gziped uuencoded postscript file including 7 figures Scheduled for
publication in Physical Review B, May 1, 1995
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