Theoretical studies of 63Cu Knight shifts of the normal state of YBa2Cu3O7

The 63Cu Knight shifts and g factors for the normal state of YBa2Cu3O7 in tetragonal phase are theoretically studied in a uniform way from the high (fourth-) order perturbation formulas of these parameters for a 3d9 ion under tetragonally elongated octahedra. The calculations are quantitatively correlated with the local structure of the Cu2+(2) site in YBa2Cu3O7. The theoretical results show good agreement with the observed values, and the improvements are achieved by adopting fewer adjustable parameters as compared to the previous works. It is found that the significant anisotropy of the Knight shifts is mainly attributed to the anisotropy of the g factors due to the orbital interactions.Comment: 5 page

Investigations of the g factors and local structure for orthorhombic Cu^{2+}(1) site in fresh PrBa_{2}Cu_{3}O_{6+x} powders

The electron paramagnetic resonance (EPR) g factors g_x, g_y and g_z of the orthorhombic Cu^{2+}(1) site in fresh PrBa_{2}Cu_{3}O_{6+x} powders are theoretically investigated using the perturbation formulas of the g factors for a 3d^9 ion under orthorhombically elongated octahedra. The local orthorhombic distortion around the Cu^{2+}(1) site due to the Jahn-Teller effect is described by the orthorhombic field parameters from the superposition model. The [CuO6]^{10-} complex is found to experience an axial elongation of about 0.04 {\AA} along c axis and the relative bond length variation of about 0.09 {\AA} along a and b axes of the Jahn-Teller nature. The theoretical results of the g factors based on the above local structure are in reasonable agreement with the experimental data.Comment: 6 pages, 1 figur

Investigations of the EPR parameters for the tetrahedral [FeX_4]^- clusters in AgX (X=Cl, Br)

The EPR parameters g factors and the superhyperfine parameters for the tetrahedral [FeX_4]^- clusters in AgX (X=Cl, Br) are theoretically investigated from the perturbation formulas of these parameters for a 3d^5 ion under tetrahedra by considering both the crystal-field and charge transfer contributions. The related model parameters are quantitatively determined from the cluster approach in a uniform way. The g-shift \Delta g (=g-g_s, where g_s\approx 2.0023 is the spin only value) from the charge transfer contribution is opposite (positive) in sign and much larger in magnitude as compared with that from the crystal-field one. The importance of the charge transfer contribution increases rapidly with increasing the covalency and the spin-orbit coupling coefficient of the ligand and thus exhibits the order of AgCl<AgBr. The unpaired spin densities of the halogen ns, np\sigma\ and np\pi\ orbitals are quantitatively determined from the related molecular orbital coefficients based on the cluster approach.Comment: 8 page

Dynamics and Berry phase of two-species Bose-Einstein condensates

In terms of exact solutions of the time-dependent Schrodinger equation for an effective giant spin modeled from a coupled two-mode Bose-Einstein condensate (BEC) with adiabatic and cyclic time-varying Raman coupling between two hyperfine states of the BEC, we obtain analytic time-evolution formulas of the population imbalance and relative phase between two components with various initial states, especially the SU(2)coherent state. We find the Berry phase depending on the number parity of atoms, and particle number dependence of the collapse revival of population-imbalance oscillation. It is shown that self-trapping and phase locking can be achieved from initial SU(2) coherent states with proper parameters.Comment: 18 pages,5 figure

Government policy as a key moderator to contractors’ risk attitudes among Malaysian construction companies

Purpose: The main parties in construction projects are the engineers, clients, architects, contractors, material suppliers, and consultants such as the project managers. They play the most important roles in implementing construction projects, and their activities have a significant impact on their risk attitudes during the execution of projects. Because each participant has their particular interests, by proprietary information, each participant is driven to achieve maximum benefit, which can result in improper behaviour concerning each other. The risk in this situation is that there would be a moral hazard and adverse selection based on information asymmetry among principal construction participants especially contractors; this outcome is called risk attitudes. Behaviour is affected by various risk factors and the successful implementation of construction projects depends on effective management of the key risk factors part of which is a personal factor. The purpose of this paper is to identify the critical factors affecting contractors’ risk attitudes among Malaysian construction companies with the moderating role of government policy. Organizational control theory and expected utility theory were used to develop the theoretical framework. The study investigated G7 contractors in the Malaysian construction industry. Data were collected through the use of a questionnaire. Design/methodology/approach: The research analysis was based on structural equation modelling (SEM), and the research model was ascertained through the Smart PLS 3.0 software (Ringle et al., 2012). Partial least square-SEM is an appropriate analysis that was used to assess the results in the current research because its algorithm permits the unrestricted computation of cause-effect relationship models that use both reflective and formative measurement models. This study uses the quantitative method to identify the individual factors influencing contractors’ risk attitude and the moderating role of government policy among construction companies in Malaysia. This study also focussed on the G7 contractors operating in the Malaysia construction industry that specializes in building, bridge and road construction projects. The duration of the data collection was between two and three weeks. The questionnaire was prepared both in Malay and English languages to allow the respondents to respond most conveniently. Before the copies of the questionnaire were distributed, the selected contractors’ committees were duly informed about the details of the survey procedures. The adopted Likert scale was originally a five-point scale that ranges from “very low” to “very high” with “low or high” in between. Findings: The result of this study moderately supports the hypothesized relationships proposed in the theoretical model. In particular, the results recommended that personal factors that affect risk attitudes (working experience, emotional intelligence, professional competence and physical health) have a significant relation with contractors’ risk attitudes in the construction companies in Malaysia. Also, it has been found that government policy (rules and regulations) are important determinants of risk attitudes. Research limitations/implications: The study focussed on individual factors affecting contractors’ risk attitudes in the construction company’s in Malaysia. Therefore, the dimensions of factors affecting risk attitudes can be used in another aspect of construction projects such as management factors, economic factors and technical factors. Therefore, further research might investigate other grades of Malaysian construction companies apart from Grade 7 contractors to know if there is a similarity in the results; other grades of the contractors might have potential positive contributions to the construction industry as well. Practical implications: With consider to the practical, the current research findings have several contributions for the contractors and project managers. The research results demonstrate that government policy plays an important role in the construction industry and organizational support will also help contractors to control their attitudes in working place. Individual factor has a direct relationship with contractor risk attitudes (CRA), project managers must ensure that the government policy has an impact in all their workers and offered is competitive, fair and by their employees’ contribution. Apart from that managers should also focus on organizational goals especially in managing professional and skilled contractors in the companies. Employees who perceived their employers as uncaring or not supporting their needs and well-being may not be happy working with the organization and the tendency for them to change their attitudes towards risk will be high. Social implications: This study also contributes knowledge by lending empirical support to the organizational control theory and expected utility theory system’s effect on CRA and confirming that changing one individual attitude will change the whole equilibrium. This is useful to aid in further synthesis of organizational control theory and expected utility theory in construction companies. Originality/value: This study is the first attempt at evaluating the direct and moderating effect relationships among individual factor affecting risk attitudes, government policy and CRA in Malaysian construction companies. These findings also prop up the applicability of the organizational control theory and expected utility theory within the context of construction companies in Malaysia. Also, this study contributed to the literature on psychology by subjective (psychological) measures of individuals’ behaviour and decisions. In the CRA literature, there has been much discussion on personal characteristics to understand behaviours such as attitudes of a contractor towards risk and morals

Conceptual design study for heat exhaust management in the ARC fusion pilot plant

The ARC pilot plant conceptual design study has been extended beyond its initial scope [B. N. Sorbom et al., FED 100 (2015) 378] to explore options for managing ~525 MW of fusion power generated in a compact, high field (B_0 = 9.2 T) tokamak that is approximately the size of JET (R_0 = 3.3 m). Taking advantage of ARC's novel design - demountable high temperature superconductor toroidal field (TF) magnets, poloidal magnetic field coils located inside the TF, and vacuum vessel (VV) immersed in molten salt FLiBe blanket - this follow-on study has identified innovative and potentially robust power exhaust management solutions.Comment: Accepted by Fusion Engineering and Desig

Characterization of brain blood flow and the amplitude of low-frequency fluctuations in major depressive disorder: A multimodal meta-analysis.

Background In healthy subjects, there is an association between amplitude of low-frequency fluctuations (ALFF) and regional cerebral blood flow (rCBF). To date, no published meta-analysis has investigated changes in the regional ALFF in medication-free depressed patients. Methods In this study, we aimed to explore whether resting-state rCBF and ALFF changes co-occur in the depressed brain without the potential confound of medication. Using signed differential mapping (SDM), we conducted two meta-analyses, one of rCBF studies and one of ALFF studies, involving medication-free patients with major depressive disorder (MDD). In addition, we conducted a multimodal meta-analysis to identify brain regions that showed abnormalities in both rCBF and ALFF. Results A total of 16 studies were included in this series. We identified abnormalities in resting-state rCBF and ALFF in the left insula in medication-free MDD patients compared with healthy controls (HC). In addition, we observed altered resting-state rCBF in the limbic-subcortical-cortical circuit and altered ALFF in the default mode network (DMN) and some motor-related brain regions. Limitations The analysis techniques, patient characteristics and clinical variables of the included studies were heterogeneous. Conclusions The conjoint alterations in ALFF and rCBF in the left insula may represent core neuropathological changes in medication-free patients with MDD and merit further studying

Defects, Dopants and Lithium Mobility in Li ₉ v ₃ (P ₂ O ₇ ) ₃ (PO ₄ ) ₂

Layered Li9V3(P2O7)3(PO4)2 has attracted considerable interest as a novel cathode material for potential use in rechargeable lithium batteries. The defect chemistry, doping behavior and lithium diffusion paths in Li9V3(P2O7)3(PO4)2 are investigated using atomistic scale simulations. Here we show that the activation energy for Li migration via the vacancy mechanism is 0.72 eV along the c-axis. Additionally, the most favourable intrinsic defect type is Li Frenkel (0.44 eV/defect) ensuring the formation of Li vacancies that are required for Li diffusion via the vacancy mechanism. The only other intrinsic defect mechanism that is close in energy is the formation of anti-site defect, in which Li and V ions exchange their positions (1.02 eV/defect) and this can play a role at higher temperatures. Considering the solution of tetravalent dopants it is calculated that they require considerable solution energies, however, the solution of GeO2 will reduce the activation energy of migration to 0.66 eV

L-Monomethyl-arginine decreases apoptosis of chondrocytes by altering Bax and Bcl-2 expression in osteoarthritis of rabbit knee

Previous studies found that NG-monomethyl-L-arginine (L-NMMA) treatment inhibits progression of osteoarthritis. Here, we aimed to explore the effects of L-NMMA on chondrocyte apoptosis and Bax and Bcl-2 mRNA expression in rabbits with knee osteoarthritis. Knee osteoarthritis was induced in 24 healthy rabbits by Hulth method, and rabbits were randomly divided into control (n = 12) and experimental (n = 12) groups. Once weekly, knee joints of control rabbits were injected with saline solution, while knees of experimental rabbits were injected with L-NMMA. Knee joint samples were collected after 6 weeks of treatment. Apoptosis of chondrocytes was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), and Bax and Bcl-2 mRNA expression by in situ hybridization. The results show that the mean rate of chondrocyte apoptosis in knees of the experimental rabbits was significantly lower than that of the control rabbits (P&lt;0.05). Additionally, Bax expression decreased and Bcl-2 expression increased in the experimental group (P&lt;0.05). In brief, LNMMA can inhibit apoptosis of joint chondrocytes through changes in the expression of apoptosisrelated genes. Thus, this molecule offers the potential for treating osteoarthritis.Key words: NG-Monomethyl-L-arginine, knee osteoarthritis, chondrocyte, apoptosis-related regulatory gene