Assessment of the GLLB-SC potential for solid-state properties and attempts for improvement

Based on the work of Gritsenko et al. (GLLB) [Phys. Rev. A 51, 1944 (1995)], the method of Kuisma et al. [Phys. Rev. B 82, 115106 (2010)] to calculate the band gap in solids was shown to be much more accurate than the common local density approximation (LDA) and generalized gradient approximation (GGA). The main feature of the GLLB-SC potential (SC stands for solid and correlation) is to lead to a nonzero derivative discontinuity that can be conveniently calculated and then added to the Kohn-Sham band gap for a comparison with the experimental band gap. In this work, a thorough comparison of GLLB-SC with other methods, e.g., the modified Becke-Johnson (mBJ) potential [F. Tran and P. Blaha, Phys. Rev. Lett. 102, 226401 (2009)], for electronic, magnetic, and density-related properties is presented. It is shown that for the band gap, GLLB-SC does not perform as well as mBJ for systems with a small band gap and strongly correlated systems, but is on average of similar accuracy as hybrid functionals. The results on itinerant metals indicate that GLLB-SC overestimates significantly the magnetic moment (much more than mBJ does), but leads to excellent results for the electric field gradient, for which mBJ is in general not recommended. In the aim of improving the results, variants of the GLLB-SC potential are also tested

Investigating viscous damping using a webcam

We describe an experiment involving a mass oscillating in a viscous fluid and analyze viscous damping of harmonic motion. The mechanical oscillator is tracked using a simple webcam and an image processing algorithm records the position of the geometrical center as a function of time. Interesting information can be extracted from the displacement-time graphs, in particular for the underdamped case. For example, we use these oscillations to determine the viscosity of the fluid. Our mean value of 1.08 \pm 0.07 mPa s for distilled water is in good agreement with the accepted value at 20\circC. This experiment has been successfully employed in the freshman lab setting.Comment: 13 pages, 5 figure

On the zeroth-order general Randi\'c index, variable sum exdeg index and trees having vertices with prescribed degree

The zeroth-order general Randi\'c index (usually denoted by $R_{\alpha}^{0}$) and variable sum exdeg index (denoted by $SEI_{a}$) of a graph $G$ are defined as $R_{\alpha}^{0}(G)= \sum_{v\in V(G)} (d_{v})^{\alpha}$ and $SEI_{a}(G)= \sum_{v\in V(G)}d_{v}a^{d_{v}}$ where $d_{v}$ is degree of the vertex $v\in V(G)$, $a$ is a positive real number different from 1 and $\alpha$ is a real number other than $0$ and $1$. A segment of a tree is a path $P$, whose terminal vertices are branching or pendent, and all non-terminal vertices (if exist) of $P$ have degree 2. For $n\ge6$, let $\mathbb{PT}_{n,n_1}$, $\mathbb{ST}_{n,k}$, $\mathbb{BT}_{n,b}$ be the collections of all $n$-vertex trees having $n_1$ pendent vertices, $k$ segments, $b$ branching vertices, respectively. In this paper, all the trees with extremum (maximum and minimum) zeroth-order general Randi\'c index and variable sum exdeg index are determined from the collections $\mathbb{PT}_{n,n_1}$, $\mathbb{ST}_{n,k}$, $\mathbb{BT}_{n,b}$. The obtained extremal trees for the collection $\mathbb{ST}_{n,k}$ are also extremal trees for the collection of all $n$-vertex trees having fixed number of vertices with degree 2 (because it is already known that the number of segments of a tree $T$ can be determined from the number of vertices of $T$ with degree 2 and vise versa).Comment: 10 page

Growth, Policy and Institutions: lessons from the Indian experience (Dr Montek Singh Ahluwalia)

Sohaib Athar offers an overview of Dr Montek Singh Ahluwalia’s talk at the LSE last Thursday

A study of individual consumer level culture in B2C e-commerce through a multi-perspective iTrust model

University of Technology Sydney. Faculty of Engineering and Information Technology.Building trust and understanding their relationship with consumer online purchasing decisions is important to business-to-consumer (B2C) e-commerce firms seeking to extend their reach to consumers globally. This study addresses the gap in the knowledge about this relationship by studying the cognitive and affective responses of consumers towards a B2C e-commerce website. Based on the Stimulus–Organism–Response (S–O–R) model, this study examines the moderating role of individual consumer culture on the relationship between web design (website accessibility, visual appearance (colour and images) and social networking services), consumer behaviour (religiosity), privacy, security, emotions (fear and joy) and interpersonal trust (iTrust), cognitive and affect-based trust concerning online purchasing intentions. The motivation of this study includes testing and comparing individual consumer cultural values (individualism and uncertainty avoidance) difference moderators in proposed multi-perspective model of online interpersonal trust (iTrust) across two different societies (Australia and Pakistan). This research applied a quantitative methodology and a cross-sectional survey design approach. In order to empirically test the research model, surveys were conducted in Pakistan and Australia. A total of 270 participants from Pakistan and 255 from Australia responded to the survey. The data of the survey were analysed with the SEM-Partial Least Square (PLS) approach using SmartPLS 3.0. The results of the analysis generated mixed findings. It was found that depending on the stimulus (S) towards which a reaction is made provides a signal regarding the cognitive and affect-based trust (Organism) of B2C e-commerce website, which influence consumers purchase intentions (Response) at the individual level across culture. The results of this study highlight the need to consider individual consumer level cultural differences when identifying the mix of e-commerce strategies to employ in B2C websites, not only at the country level but also in culturally diverse country such as Australia

Electrocardiographic (ECG) criteria for determining left ventricular mass in young healthy men; data from the LARGE Heart study

Background: Doubts remain over the use of the ECG in identifying those with increased left ventricular (LV) mass. This is especially so in young individuals, despite their high prevalence of ECG criteria for LV hypertrophy. We performed a study using cardiovascular magnetic resonance (CMR), which provides an in vivo non-invasive gold standard method of measuring LV mass, allowing accurate assessment of electrocardiography as a tool for defining LV hypertrophy in the young.Methods and results: Standard 12-lead ECGs were obtained from 101 Caucasian male army recruits aged (mean +/- SEM) 19.7 +/- 0.2 years. LV mass was measured using CMR. LV mass indexed to body surface area demonstrated no significant correlation with the Cornell Amplitude criteria or Cornell Product for LV hypertrophy. Moderate correlations were seen with the Sokolow-Lyon Amplitude (0.28) and Sokolow-Lyon Product (0.284). Defining LV hypertrophy as a body surface area indexed left ventricular mass of 93 g/m(2), calculated sensitivities [and specificities] were as follows; 38.7% [74.3%] for the Sokolow-Lyon criteria, 43.4% [61.4%] for the Sokolow-Lyon Product, 19.4% [91.4%] for Cornell Amplitude, and 22.6% [85.7%] for Cornell Product. These values are substantially less than those reported for older age groups.Conclusion: ECG criteria for LV hypertrophy may have little value in determining LV mass or the presence of LV hypertrophy in young fit males

Assessing web content accessibility of E-commerce websites for people with disabilities

In recent years online shopping has grown significantly. Due to the rapid growth of technology, companies also continuing to extend the functionality and design of their Business-to-Consumer (B2C) e-business websites. However, it is also important to adopt web accessibility such as the Web Content Accessibility Guidelines in B2C websites to increase the consumer's satisfaction of all ages and with disabilities. This study analyses 30 Australian B2C websites in accordance to Web Content Accessibility Guidelines (WCAG 2.0) using an automated web service. The result shows that B2C websites in Australia are not paying attention to web accessibility for people with disabilities. However, e-commerce will succeed in meeting WCAG 2.0 by making B2C e-commerce websites accessible to consumer of all ages and with disabilities. Recommendations are proposed in order to improve web accessibility for people with sensory (hearing and vision), motor (limited use of hands) and cognition (language and learning) disabilities in B2C e-commerce websites

The Influence of Culture on iTrust Aspects in B2C E-Business

This research suggests an online interpersonal trust (iTrust) to better understand the buyer cognitive and affective reactions towards online purchasing. To complete this main goal, this study provides proposition on the effect of culture (Individualistic and collectivistic) on online interpersonal trust (cognitive and affect-based trust) related to web design and buyer behavior aspects towards purchase intention in B2C e-business website. It is important to compare online shopping perceptions between two different groups because the Individualistic buyers‟ satisfaction may be completely ineffective in producing a desired response in the Collectivistic

Enhancing innovative capability and sustainability of Saudi firms

© 2016 by the author. The Saudi Arabian government has recognised the need for an alternative path to national development in the form of a knowledge-based economy (KBE). One of the key drivers of a knowledge-based economy KBE is innovation. Therefore, to achieve this aim, it is important to understand the various factors affecting organisational innovation capability and sustainability. This empirical research study was conducted to provide a better understanding of the interrelationships among the key constructs, socio-technical factors, diffusion of innovation, and knowledge-sharing process towards Saudi organisational innovation capability. The results offer a number of implications, which are beneficial towards the adoption of the knowledge-based economy seeking to enhance the Saudi organisations towards enriching the organisational innovation capability and sustainability