Excitations in cubic BaSnO3_{3}: a consistent picture revealed by combining theory and experiment

Among the transparent conducting oxides, the perovskite barium stannate is most promising for various electronic applications due to its outstanding carrier mobility achieved at room temperature. Most important characteristics however, $i.e.$, its band gap, effective masses, and absorption edge remain controversial. Here, we provide a fully consistent picture by combining state-of-the-art $ab~initio$ methodology with forefront electron energy-loss spectroscopy (EELS) and optical absorption measurements. On- and off-axis valence EELS spectra, featuring signals originating from band gap transitions, are acquired on defect-free sample regions of a BaSnO$_{3}$ single crystal. These high-energy-resolution measurements are able to capture also very weak excitations below the optical gap, attributed to indirect transitions. By temperature-dependent optical absorption measurements, we assess band-gap renormalization effects induced by electron-phonon coupling. Overall, we find for the effective electronic mass, the direct and the indirect gap, the optical gap as well as the absorption onsets and spectra excellent agreement between both experimental techniques and the theoretical many-body results, supporting also the picture of a phonon-mediated mechanism where indirect transitions are activated by phonon-induced symmetry lowering. This work demonstrates a fruitful connection between different high-level theoretical and experimental methods for exploring the characteristics of advanced materials

Interruzioni e cesure. Fenomeni e pratiche della discontinuità in linguistica, letteratura e arti performative

Comparare è una necessità e una scommessa, quando non un azzardo, che continua a metterci di fronte a difficoltà inaggirabili. La prima si chiama specialismo: ogni studioso è in questa condizione, cui di fatto le istituzioni accademiche spingono anche quando sembrano favorire gli incontri fra discipline diverse. Il paradosso è dunque che non si può dare comparazione seria se prima non si è data una qualche forma di specialismo. È questo lo spirito che anima i contributi raccolti in questo volume. I saggi qui raccolti, infatti, affrontano il tema dell’interruzione e della cesura da prospettive e con approcci molteplici, in una varietà di studi che complessivamente ricadono negli ambiti della linguistica, della letteratura e della metrica. Sta al lettore individuare le intersezioni possibili, guidato dai propri interessi, come anche riconoscere che, in una certa misura, ci sono metodi o approcci o declinazioni di uno stesso tema non sovrapponibili

Personality profiles of cultures: aggregate personality traits

Personality profiles of cultures can be operationalized as the mean trait levels of culture members. College students from 51 cultures rated an individual from their country whom they knew well (N = 12, 156). Aggregate scores on Revised NEO Personality Inventory scales generalized across age and gender groups, approximated the individual-level Five-Factor Model, and correlated with aggregate self-report personality scores and other culture-level variables. Results were not attributable to national differences in economic development or to acquiescence. Geographical differences in scale variances and mean levels were replicated, with Europeans and Americans generally scoring higher in Extraversion than Asians and Africans. Findings support the rough scalar equivalence of NEO-PI-R factors and facets across cultures, and suggest that aggregate personality profiles provide insight into cultural differences

Digital versus Conventional Dentures: A Prospective, Randomized Cross-Over Study on Clinical Efficiency and Patient Satisfaction

Digital technology facilitates the manufacturing of complete dentures; however, clinical and patient-reported outcomes are underreported. This prospective, randomized, single-blind cross-over study reports the clinical and patient-related outcomes of 10 edentulous patients receiving digital dentures prepared with the Vita Vionic System and conventional dentures produced from heat-polymerized polymethylmethacrylate resin. Clinical efficiency was stated based on the Sato score for quantitative assessment of complete denture quality. Patient satisfaction was evaluated with the oral health-related quality of life questionnaire (OHIP-20). We report here that the Sato score was slightly higher in patients receiving digital versus conventional dentures with a mean of 73.2 ± 12.3 and 67.4 ± 11.8, respectively (p = 0.16). Moreover, upper and lower stability was superior in digital dentures (p = 0.03 and p = 0.10, respectively), while denture polish was better in conventional dentures (p = 0.03). Quality of life was slightly higher in patients receiving conventional compared to digital dentures with an OHIP-20 of 101.7 ± 12.0 and 95.6 ± 24.2, respectively (p = 0.33). Taken together and when considering the low power of the study, our findings suggest a trend towards better clinical efficiency of digital compared to conventional dentures, while patient satisfaction remained unaffected by the type of manufacturing

Polar discontinuity governs surface segregation and interface termination: A case study of LaInO3_3/BaSnO3_3

We combine (scanning) transmission electron microscopy, electron energy loss spectroscopy (EELS), and x-ray photoelectron spectroscopy (XPS) with density functional theory (DFT) to investigate the complex interplay of surface energetics and polar discontinuity compensation in the interface formation of (001) LaInO$_3$/BaSnO$_3$-based heterostructures. We present evidence from both experiment and theory that the BaSnO$_3$ surface with BaO termination is energetically favored over a wide range of chemical potentials. However, overgrowth of the nonpolar BaO-terminated surface with LaInO$_3$ results in a SnO$_2$-terminated interface. EELS and XPS show that this interfacial termination exchange is mediated by Ba segregation to the growth surface. Our DFT calculations show that the efficient compensation of the polar discontinuity, attributed to polar distortions within BaSnO$_3$ at the SnO$_2$-terminated interface, serves as the driving force behind the observed Ba segregation. This intricate interplay underscores the importance of polar discontinuity compensation as a pivotal factor influencing interface formation in perovskite systems

Melt Growth and Physical Properties of Bulk LaInO3 Single Crystals

Large bulk LaInO3 single crystals are grown from the melt contained within iridium crucibles by the vertical gradient freeze (VGF) method. The obtained crystals are undoped or intentionally doped with Ba or Ce, and enabled wafer fabrication of size 10 × 10 mm2. High melting point of LaInO3 (≈1880 °C) and thermal instability at high temperatures require specific conditions for bulk crystal growth. The crystals do not undergo any phase transition up to 1300 °C, above which a noticeable thermal decomposition takes place. The good structural quality of the crystals makes them suitable for epitaxy. The onset of strong optical absorption shows orientation-dependent behavior due to the orthorhombic symmetry of the LaInO3 crystals. Assuming direct transitions, optical bandgaps of 4.35 and 4.39 eV are obtained for polarizations along the [010] and the [100], [001] crystallographic directions, respectively. There is an additional weak absorption in the range between 2.8 and 4 eV due to oxygen vacancies. Density-functional-theory calculations support the interpretation of the optical absorption data. Cathodoluminescence spectra show a broad, structured emission band peaking at ≈2.2 eV. All bulk crystals are electrically insulating. The relative static dielectric constant is determined at a value of 24.6 along the [001] direction

Class II malocclusion occlusal severity description

OBJECTIVES: It is well known that the efficacy and the efficiency of a Class II malocclusion treatment are aspects closely related to the severity of the dental anteroposterior discrepancy. Even though, sample selection based on cephalometric variables without considering the severity of the occlusal anteroposterior discrepancy is still common in current papers. In some of them, when occlusal parameters are chosen, the severity is often neglected. The purpose of this study is to verify the importance given to the classification of Class II malocclusion, based on the criteria used for sample selection in a great number of papers published in the orthodontic journal with the highest impact factor. MATERIAL AND METHODS: A search was performed in PubMed database for full-text research papers referencing Class II malocclusion in the history of the American Journal of Orthodontics and Dentofacial Orthopedics (AJO-DO). RESULTS: A total of 359 papers were retrieved, among which only 72 (20.06%) papers described the occlusal severity of the Class II malocclusion sample. In the other 287 (79.94%) papers that did not specify the anteroposterior discrepancy severity, description was considered to be crucial in 159 (55.40%) of them. CONCLUSIONS: Omission in describing the occlusal severity demands a cautious interpretation of 44.29% of the papers retrieved in this study

Universal features of personality traits from the observer’ s perspective: data from 50 cultures

To test hypotheses about the universality of personality traits, college students in 50 cultures identified an adult or college-age man or woman whom they knew well and rated the 11, 985 targets using the third-person version of the Revised NEO Personality Inventory. Factor analyses within cultures showed that the normative American self-report structure was clearly replicated in most cultures, and was recognizable in all. Sex differences replicated earlier self-report results, with the most pronounced differences in Western cultures. Cross-sectional age differences for three factors followed the pattern identified in self-reports, with moderate rates of change during college age and very slow changes after age 40. With a few exceptions, these data support the hypothesis that features of personality traits are common to all human groups