414 research outputs found
The high-pressure alpha/beta phase transition in lead sulphide (PbS): X-ray powder diffraction and quantum mechanical calculations
The high-pressure behaviour of PbS was investigated by angular dispersive
X-ray powder diffraction up to pressures of 6.8 GPa. Experiments were
accompanied by first principles calculations at the density functional theory
level. By combining both methods reliable data for the elastic properties of
rock-salt type alpha- and high-pressure beta-PbS could be obtained. beta-PbS
could be determined to crystallise in the CrB-type (B33), with space group
Cmcm. The reversible ferro-elastic alpha/beta transition is of first order. It
is accompanied by a large volume discontinuity of about 5% and a coexistence
region of the two phases. A gliding mechanism of {001} bilayers along one of
the cubic -directions governs the phase transition which can be described
in terms of group/subgroup relationships via a common subgroup, despite its
reconstructive character. The quadrupling of the primitive unit cell indicates
a wave vector (0,0,pi/a) on the Delta-line of the Brillouin zone.Comment: 7 pages, 5 figures, 3 tables submitted to EP
Examining the contribution of RAN components to reading fluency, reading comprehension, and spelling in German
We examined the contribution of rapid automatized naming (RAN) components (articulation time, pause time, and pause time consistency) to reading fluency, reading comprehension, and spelling in a sample of 257 German children (139 boys, 118 girls; Mageā=ā5.60 years, SDā=ā0.31) followed from kindergarten to Grade 1. In kindergarten, children were assessed on measures of RAN (colors and objects), phonological awareness, letter-sound knowledge, phonological short-term memory, and paired-associate learning. Reading fluency, reading comprehension, and spelling were assessed at the end of Grade 1. Hierarchical regression analyses revealed that pause time and pause time consistency continued to predict reading fluency, but not reading comprehension or spelling, after controlling for the effects of the other cognitive skills assessed in kindergarten. Articulation time did not add to the prediction of any literacy skills. These findings support previous research suggesting that, during the early phases of learning to read, pause time holds the key in the relation between RAN and reading fluency. (DIPF/Orig,
SARS-CoV-2 Vaccination in the Context of Ongoing HIV Cure-Related Research Studies
To the Editors: The SARS-CoV-2 pandemic has affected research efforts worldwide. Previously, we described our strategy to mitigate COVID-19 transmission risk during an ongoing HIV cure-related clinical trial. SARS-CoV-2 vaccines recently have been authorized for emergency use and will become available to people with HIV imminently. As a result, researchers must determine how to adjust study protocols to incorporate the likelihood that participants may be vaccinated
Temperature dependence of the Kondo resonance and its satellites in CeCu_2Si_2
We present high-resolution photoemission spectroscopy studies on the Kondo
resonance of the strongly-correlated Ce system CeCuSi. Exploiting the
thermal broadening of the Fermi edge we analyze position, spectral weight, and
temperature dependence of the low-energy 4f spectral features, whose major
weight lies above the Fermi level . We also present theoretical
predictions based on the single-impurity Anderson model using an extended
non-crossing approximation (NCA), including all spin-orbit and crystal field
splittings of the 4f states. The excellent agreement between theory and
experiment provides strong evidence that the spectral properties of
CeCuSi can be described by single-impurity Kondo physics down to K.Comment: 4 pages, 3 figure
The Kondo Resonance in Electron Spectroscopy
The Kondo resonance is the spectral manifestation of the Kondo properties of
the impurity Anderson model, and also plays a central role in the dynamical
mean-field theory (DMFT) for correlated electron lattice systems. This article
presents an overview of electron spectroscopy studies of the resonance for the
4f electrons of cerium compounds, and for the 3d electrons of V_2O_3, including
beginning efforts at using angle resolved photoemission to determine the
k-dependence of the resonance. The overview includes the comparison and
analysis of spectroscopy data with theoretical spectra as calculated for the
impurity model and as obtained by DMFT, and the Kondo volume collapse
calculation of the cerium alpha-gamma phase transition boundary, with its
spectroscopic underpinnings.Comment: 32 pages, 11 figures, 151 references; paper for special issue of J.
Phys. Soc. Jpn. on "Kondo Effect--40 Years after the Discovery
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Towards development of sustainable lightweight 3D printed wall building envelopes ā Experimental and numerical studies
Data Availability: Data will be made available on request.Copyright Ā© The Authors 2023. 3D printing technology can be of crucial importance in the design of sustainable and energy-efficient building envelopes. With this technology, there is the potential to mechanically and thermally optimise the topology of printed walls. Additionally, the printing and infill materials used can be insulating, and thus contributing to the overall reduction of heat loss. To date, limited examples of 3D printed envelopes and information about the thermal and mechanical performance of 3D printed walls are available. This study developed a 3D printable wall element with an insulating property for application in building envelopes. Seven wall topologies are studied through simulations of mechanical and thermal performance using two mixtures: a control mixture (normal-weight) and a lightweight mixture containing expanded thermoplastic microspheres (ETM) for thermal insulation. One wall topology is selected based on the performance of the simulation and printed using both mixtures. The 3D printed envelopes were tested under compressive strength and analysed with the ARAMIS system, a digital image correlation (DIC) technology. Computer simulations and the DIC analysis identified the main causes for failure, which are the inter-filament weakness and the imperfections of the geometry of the printed envelope.European Unionās Horizon 2020 research and innovation program as part of Marie SkÅodowska-Curie Grant agreement no. 841592; Deutscher Akademischer Austauschdienst under Grant no. 57552340
Adjunctive mood stabilizer treatment for hospitalized schizophrenia patients: Asia psychotropic prescripton study (2001-2008)
Recent studies indicate relatively high international rates of adjunctive psychotropic medication, including mood stabilizers, for patients with schizophrenia. Since such treatments are little studied in Asia, we examined the frequency of mood-stabilizer use and its clinical correlates among hospitalized Asian patients diagnosed with schizophrenia in 2001-2008. We evaluated usage rates of mood stabilizers with antipsychotic drugs, and associated factors, for in-patients diagnosed with DSM-IV schizophrenia in 2001, 2004 and 2008 in nine Asian regions: China, Hong Kong, India, Korea, Japan, Malaysia, Taiwan, Thailand, and Singapore. Overall, mood stabilizers were given to 20.4% (n=1377/6761) of hospitalized schizophrenia patients, with increased usage over time. Mood-stabilizer use was significantly and independently associated in multivariate logistic modeling with: aggressive behaviour, disorganized speech, year sampled (2008 vs. earlier), multiple hospitalizations, less negative symptoms, younger age, with regional variation (Japan, Hong Kong, Singapore>Taiwan or China). Co-prescription of adjunctive mood stabilizers with antipsychotics for hospitalized Asian schizophrenia patients increased over the past decade, and was associated with specific clinical characteristics. This practice parallels findings in other countries and illustrates ongoing tension between evidence-based practice vs. individualized, empirical treatment of psychotic disorders.published_or_final_versio
Genome-Wide Linkage Scan in Gullah-Speaking African American Families With Type 2 Diabetes: The Sea Islands Genetic African American Registry (Project SuGAR)
OBJECTIVEāThe Gullah-speaking African American population from the Sea Islands of South Carolina is characterized by a low degree of European admixture and high rates of type 2 diabetes and diabetic complications. Affected relative pairs with type 2 diabetes were recruited through the Sea Islands Genetic African American Registry (Project SuGAR)
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