527 research outputs found
Cultural Influnces on Risk Tolerance and Portfolio Creation
We extend existing research that examines the impact of culture on risk tolerance. Using surveys completed by Chinese and American students, we find, consistent with previous studies, that Chinese students perceive themselves as more risk tolerant. However, we find that Chinese students are less consistent in matching their perceived tolerance levels with actual scores from a standard risk tolerance assessment. Further, we also examine mock portfolios created by the respondents and find no evidence that Chinese students create portfolios that are riskier than their American counterparts. Our findings suggest that differences in risk tolerance are at least partially a product of culture, but such differences may not always translate into actual investment decisions
Higher superconducting transition temperature by breaking the universal pressure relation
By investigating the bulk superconducting state via dc magnetization
measurements, we have discovered a common resurgence of the superconductive
transition temperatures (Tcs) of the monolayer Bi2Sr2CuO6+{\delta} (Bi2201) and
bilayer Bi2Sr2CaCu2O8+{\delta} (Bi2212) to beyond the maximum Tcs (Tc-maxs)
predicted by the universal relation between Tc and doping (p) or pressure (P)
at higher pressures. The Tc of under-doped Bi2201 initially increases from 9.6
K at ambient to a peak at ~ 23 K at ~ 26 GPa and then drops as expected from
the universal Tc-P relation. However, at pressures above ~ 40 GPa, Tc rises
rapidly without any sign of saturation up to ~ 30 K at ~ 51 GPa. Similarly, the
Tc for the slightly overdoped Bi2212 increases after passing a broad valley
between 20-36 GPa and reaches ~ 90 K without any sign of saturation at ~ 56
GPa. We have therefore attributed this Tc-resurgence to a possible
pressure-induced electronic transition in the cuprate compounds due to a charge
transfer between the Cu 3d_(x^2-y^2 ) and the O 2p bands projected from a
hybrid bonding state, leading to an increase of the density of states at the
Fermi level, in agreement with our density functional theory calculations.
Similar Tc-P behavior has also been reported in the trilayer
Br2Sr2Ca2Cu3O10+{\delta} (Bi2223). These observations suggest that higher Tcs
than those previously reported for the layered cuprate high temperature
superconductors can be achieved by breaking away from the universal Tc-P
relation through the application of higher pressures.Comment: 13 pages, including 5 figure
Localized Histoplasma capsulatum osteomyelitis of the fibula in an immunocompetent teenage boy: a case report
BACKGROUND: Infection of local bone with Histoplasma capsulatum is rare and difficult to diagnosis, and occurs particularly in immunocompetent subjects, who are more likely to be affected by a wide range of organisms. CASE PRESENTATION: An 11-year-old boy presented with localized histoplasmosis osteomyelitis in the left fibula without any evidence of abnormal immunological function or systemic disease. After surgical clearance of the lesion and homologous cancellous bone, the patient was treated orally with voriconazole for 6 months. The patient completely recovered with full function of his left leg during the 5-year follow-up. CONCLUSIONS: Histoplasmosis osteomyelitis can occasionally occur in immunocompetent individuals and can be complete cured by surgical clearance of the lesion and antibiotic treatment
The influence of L1 knowledge, meaning knowledge and language exposure on the processing and production of english collocations among EFL learners
Interlingual influence plays a critical role in the acquisition of English collocations. L2 learners often produced L1-based errors (Nesselhauf, 2003). However, the working mechanism of interlingual influence on the acquisition of L2 collocations is not fully understood. The current study aimed to ascertain the positive and negative effects of L1 on the acquisition of English collocations among EFL learners by examining congruency effects on collocation processing and production, the activation of L1 in the processing as well as the errors in collocation production. The study also investigated the effects of meaning knowledge and language exposure on the acquisition of English collocations. Participants are 60 Chinese EFL learners and they were divided into two groups according to their English proficiency. Reaction Time (RT) research techniques and a productive test were utilized to examine L1 influence on English collocation processing and production respectively. The data of the processing tasks were analyzed in quantitative ways, and the data of the productive test were firstly analyzed with statistical techniques and were further analyzed with the technique of Error Analysis. The study has gained significant congruency effects on processing (p<.001) and production (p<.001), significant priming effects of L1, with F (2,58)=49.004, P<.01, on the processing of incongruent collocations, but non-significant effects of language exposure and meaning knowledge. Almost a half of incongruent collocations were given more than 50% L1-induced deviant answers in production. The results revealed that L1 played positive and negative roles in the acquisition of English collocations, and transferred L1 would be fossilized in L2 lexicon and was hard to be discarded. The findings provide insights into interlingual influence on English collocation processing and production, as well as some implications for theory construction. Based on the findings, the study gave suggestions for pedagogical practice on L2 collocation acquisition and further research
Quantum Transport and Band Structure Evolution under High Magnetic Field in Few-Layer Tellurene
Quantum Hall effect (QHE) is a macroscopic manifestation of quantized states
which only occurs in confined two-dimensional electron gas (2DEG) systems.
Experimentally, QHE is hosted in high mobility 2DEG with large external
magnetic field at low temperature. Two-dimensional van der Waals materials,
such as graphene and black phosphorus, are considered interesting material
systems to study quantum transport, because it could unveil unique host
material properties due to its easy accessibility of monolayer or few-layer
thin films at 2D quantum limit. Here for the first time, we report direct
observation of QHE in a novel low-dimensional material system:
tellurene.High-quality 2D tellurene thin films were acquired from recently
reported hydrothermal method with high hole mobility of nearly 3,000 cm2/Vs at
low temperatures, which allows the observation of well-developed
Shubnikov-de-Haas (SdH) oscillations and QHE. A four-fold degeneracy of Landau
levels in SdH oscillations and QHE was revealed. Quantum oscillations were
investigated under different gate biases, tilted magnetic fields and various
temperatures, and the results manifest the inherent information of the
electronic structure of Te. Anomalies in both temperature-dependent oscillation
amplitudes and transport characteristics were observed which are ascribed to
the interplay between Zeeman effect and spin-orbit coupling as depicted by the
density functional theory (DFT) calculations
Influence of Cutter Errors on Forming Accurate Variable Hyperbolic Circular Arc Tooth Trace Cylindrical Gears
The cutter error is an important factor in the accurate forming of the variable hyperbolic circular arc tooth trace (VH-CATT) cylindrical gears. Also, the study of the relationship between the cutter error and the forming of accurate teeth is beneficial for the gear modification design and the improvement in contact performance. Firstly, based on the principle of forming VH-CATT cylindrical gears, the sources of error in the tooth forming related to accuracy were analysed, including the errors in the cutter position and the cutter geometry, such as the error of rotation around the x-axis g, the error of rotation around the y-axis b, the error of translation along the x-axis Δx, the error of translation along the y-axis Δy, the error of translation along the z-axis Δz, the pressure angle error Δa and the tooth line radius error ΔRT. Next, based on the meshing theory and processing, an ideal tooth surface equation and a tooth surface equation with cutter errors were derived, and the tooth surface reconstruction was done. Then, the gear tooth thickness error was defined to characterize the accuracy of gear forming. Finally, the influences of the cutter error on the tooth thickness error and gear contact were investigated. The study shows that all cutter errors have certain influence on the tooth thickness error, contact area and load distribution; Δx has basically no effect on the gear tooth thickness error; Δx and g make the actual meshing point deviate from the middle section. The study content and the applied methods are helpful in the tooth surface error traceability, the counter-adjustment of the tooth surface processing and the modification design. This study provides also a basis for gear design and load-bearing contact analysis
2-(2,4,6-Trimethylphenyl)-1,10-phenanthroline
In the title molecule, C21H18N2, the mean plane of the benzene ring of the mesityl group forms a dihedral angle of 82.69 (4)° with that of the phenanthroline ring system. The crystal structure is stabilized by π–π stacking interactions between the phenanthroline system and the benzene ring of the mesityl group of a symmetry-related molecule, with centroid–centroid distances of 3.7776 (14) and 3.7155 (13) Å
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