First-principles based force-field for the interaction of proteins with Au(100)(5 x 1): an extension of GolP-CHARMM

Noncovalent recognition between peptides and inorganic materials is an established phenomenon. Key to exploiting these interactions in a wide range of materials self-assembly applications would be to harness the facet-selective control of peptide binding onto these materials. Fundamental understanding of what drives facet-selectivity in peptide binding is developing, but as yet is not sufficient to enable design of predictable facet-specific sequences. Computational simulation of the aqueous peptide-gold interface, commonly used to understand the mechanisms driving adsorption at an atomic level, has thus far neglected the role that surface reconstruction might play in facet specificity. Here the polarizable GolP-CHARMM suite of force fields is extended to include the reconstructed Au(100) surface. The force field, compatible with the bio-organic force field CHARMM, is parametrized using first-principles data. Our extended force field is tailored to reproduce the heterogeneity of weak chemisorbing N and S species to specific locations in the Au(100)(5 × 1) surface identified from the first-principles calculations. We apply our new model to predict and compare the three-dimensional structure of liquid water at Au(111), Au(100)(1 × 1), and Au(100)(5 × 1) interfaces. Using molecular dynamics simulations, we predict an increased likelihood for water-mediated peptide adsorption at the aqueous-Au(100)(1 × 1) interface compared with the Au(100)(5 × 1) interface. Therefore, our findings suggest that peptide binding can discriminate between the native and reconstructed Au(100) interfaces and that the role of reconstruction on binding at the Au(100) interface should not be neglected. © 2013 American Chemical Society.

Three algorithms for learning artificial neural network: A comparison for induction motor flux estimation

This paper presents a comparative study of three algorithms for learning artificial neural network. As neural estimator, back-propagation (BP) algorithm, uncorrelated real time recurrent learning (URTRL) algorithm and correlated real time recurrent learning (CRTRL) algorithm are used in the present work to learn the artificial neural network (ANN). The approach proposed here is based on the flux estimation of high performance induction motor drives. Simulation of the drive system was carried out to study the performance of the motor drive. It is observed that the proposed CRTRL algorithm based methodology provides better performance than the BP and URTRL algorithm based technique. The proposed method can be used for accurate measurement of the rotor flux.

Did the late-2000s financial crisis influence construction labour productivity?

The late-2000s global financial crisis has wrought dramatic impacts on the construction industry. However, the issue of whether the crisis influenced the behaviours of the construction industry has not been addressed yet. This research presents an econometric approach to investigating the effects of the recent global financial crisis on construction labour productivity. By employing the error correction model and panel regression methods, the direct and indirect effects of the financial crisis on the changes in Australian construction labour productivity are explored at national and state levels. Neither the direct nor the indirect effects appear statistically significant. The results indicate that the direct effect of the financial crisis drives up construction labour productivity at the national level, while the indirect effect diminishes productivity. The effects of the financial crisis on the state construction labour productivity vary from state to state. The financial crisis influenced construction labour productivity directly and significantly in the northern and eastern regions, while the direct effects appear not significant in the other states and territories. The indirect effects of the financial crisis on productivity are statistically significant in three regions: the Australian Capital Territory, the Northern Territory and Western Australia. By comparison, the model with the financial effects fails to provide more accurate simulating results. As such, this research concludes that the influence of the late-2000s financial crisis on Australian national and state construction labour productivity is limited.

Response of BRAF-mutant melanoma to BRAF inhibition is mediated by a network of transcriptional regulators of glycolysis.

Deregulated glucose metabolism fulfills the energetic and biosynthetic requirements for tumor growth driven by oncogenes. Because inhibition of oncogenic BRAF causes profound reductions in glucose uptake and a strong clinical benefit in BRAF-mutant melanoma, we examined the role of energy metabolism in responses to BRAF inhibition. We observed pronounced and consistent decreases in glycolytic activity in BRAF-mutant melanoma cells. Moreover, we identified a network of BRAF-regulated transcription factors that control glycolysis in melanoma cells. Remarkably, this network of transcription factors, including hypoxia-inducible factor-1α, MYC, and MONDOA (MLXIP), drives glycolysis downstream of BRAF(V600), is critical for responses to BRAF inhibition, and is modulated by BRAF inhibition in clinical melanoma specimens. Furthermore, we show that concurrent inhibition of BRAF and glycolysis induces cell death in BRAF inhibitor (BRAFi)-resistant melanoma cells. Thus, we provide a proof-of-principle for treatment of melanoma with combinations of BRAFis and glycolysis inhibitors.

Polyoxometalate-based hybrid organogels prepared from a triblock copolymer via charge-driven assembly

We report a novel approach for the preparation of polyoxometalate-based hybrid organogels from a triblock copolymer via charge-induced assembly. The triblock copolymer used is poly(4-vinyl pyridine)-block-poly(ethylene glycol)-block-poly(4-vinyl pyridine) (4VPm-EGn-4VP m), and polyoxometalate (POM) is phosphotungstic acid (HPW). The ionic interaction between the pyridine groups of the 4VPm-EG n-4VPm and HPW drives the assembly of the triblock copolymer to form solvophobic cores. The PEG middle blocks connect and stabilize the different cores to form hybrid organogels. The structures of POM remain unchanged in these hybrid organogels, and the properties of POMs can be preserved, which has been confirmed by the existence of photo-reduction properties of POM in the hybrid organogels. © 2014 the Partner Organisations.

Expression and purification of soluble recombinant full length HIV-1 Pr55(Gag) protein in Escherichia coli

The HIV-1 Gag precursor protein, Pr55(Gag), is a multi-domain polyprotein that drives HIV-1 assembly. The morphological features of HIV-1 suggested Pr55(Gag) assumes a variety of different conformations during virion assembly and maturation, yet structural determination of HIV-1 Pr55(Gag) has not been possible due to an inability to express and to isolate large amounts of full-length recombinant Pr55(Gag) for biophysical and biochemical analyses. This challenge is further complicated by HIV-1 Gag's natural propensity to multimerize for the formation of viral particle (with ∼2500 Gag molecules per virion), and this has led Pr55(Gag) to aggregate and be expressed as inclusion bodies in a number of in vitro protein expression systems. This study reported the production of a recombinant form of HIV-1 Pr55(Gag) using a bacterial heterologous expression system. Recombinant HIV-1 Pr55(Gag) was expressed with a C-terminal His×6 tag, and purified using a combination of immobilized metal affinity chromatography and size exclusion chromatography. This procedure resulted in the production of milligram quantities of high purity HIV-1 Pr55(Gag) that has a mobility that resembles a trimer in solution using size exclusion chromatography analysis. The high quantity and purity of the full length HIV Gag will be suitable for structural and functional studies to further understand the process of viral assembly, maturation and the development of inhibitors to interfere with the process.

Early childhood teachers' perspectives on and experience of multicultural education

The multicultural nature of early childhood services in New Zealand is highlighted by the statistical reality that 22 percent of children are Māori, 7 percent are Pasifika, and 11 percent are Asian and other non-European/Pākehā ethnicities. Multicultural early childhood education has become a vital practice underpinning educational reforms. This is evident in a range of government initiatives including, for example, building partnerships with whānau Māori to improve Māori success in education, introducing equity funding to reduce educational disparities between different community groups, and developing a Pasifika Education Plan that improves Pasifika children’s educational achievement. In this article, multicultural education is examined, considering early childhood teachers’ perspectives and experiences through the lens of Sleeter and Grant’s five approaches to multicultural education. The findings suggest that the teachers’ focus on children, culture, and community building drives their endeavours, and indicate that the use of a social reconstructionist approach has the potential to lead to transformative changes to multicultural education.

Exhibitions as sub-brands: an exploratory study

The purpose of this paper is to explore the adoption of major exhibitions, often called blockbusters, as a sub-branding strategy for art museums. Focusing the experience around one location but drawing on a wide data set for comparative purposes, the authors examine the blockbuster phenomenon as exhibition packages sourced from international institutions, based on an artist or collection of quality and significance. The authors answer the questions: what drives an art museum to adopt an exhibition sub-brand strategy that sees exhibitions become blockbusters? What are the characteristics of the blockbuster sub-brand?

Habitat switching by Bewick's swans: Maximization of average long-term energy gain?

1. In a system where depletion drives a habitat shift, the hypothesis was tested that animals switch habitat as soon as the average daily net energy intake (or gain) drops below that attainable in the alternative habitat.

2. The study was performed in the Lauwersmeer area. Upon arrival during the autumn migration, Bewick's swans first feed on below-ground tubers of fennel pondweed on the lake, but subsequently switched to feeding on harvest remains in sugar beet fields.

3. The daily energy intake was estimated by multiplying the average time spent foraging per day with the instantaneous energy intake rate while foraging. In the case of pondweed feeding, the latter was estimated from the functional response and the depletion of tuber biomass. In the case of beet feeding, it was estimated from dropping production rate. Gross energy intake was converted to metabolizable energy intake using the assimilation as determined in digestion trials. The daily energy expenditure was estimated by the time-energy budget method. Energetic costs were determined using heart rate.

4. The daily gain of pondweed feeding at the median date of the habitat switch (i.e. when 50% of the swans had switched) was compared with that of beet feeding. The daily gain of beet feeding was calculated for two strategies depending on the night activity on the lake: additional pondweed feeding (mixed feeding) or sleeping (pure beet feeding).

5. The majority of the swans switched when the daily gain they could achieve by staying on the pondweed bed fell just below the average daily gain of pure beet feeders. However, mixed feeders would attain an average daily gain considerably above that of pondweed feeders. A sensitivity analysis showed that this result was robust.

6. We therefore reject the hypothesis that the habitat switch by swans can be explained by simple long-term energy rate maximization. State-dependency, predation risk, and protein requirements are put forward as explanations for the delay in habitat switch.

Managerial ownership, capital structure and firm value: Evidence from China’s civilian-run firms

This paper examines the influence of managerial ownership on firm performance through capital-structure choices, using a sample of China’s civilian-run firms listed on the Chinese stock market between 2002 and 2007. The empirical results demonstrate a nonlinear relationship between managerial ownership and firm value. Managerial ownership drives the capital structure into a nonlinear shape, but in an opposite direction to the effect of managerial ownership on firm value. The results of simultaneous regressions suggest that managerial ownership affects capital structure, which in turn affects firm value. Our findings imply that the “interest convergence” and “entrenchment” effects of managers’ behaviour in terms of managerial ownership can also explain the agency-relevant situation of China’s civilian-run firms.

Managerial ownership, capital structure and firm value

This paper extends prior research to examine the managerial ownership influences on firm performance through the choices of capital structures by using a new sample of S& P 500 firm in 2005. The empirical results of OLS regressions replicate the nonlinear relationship between managerial ownership and firm value. However, we found that the turning points had moved up in our sample compared with previous papers, which implies that the managerial control for pursuing self-interst, and the alignment of interests between managers and other shareholders can only be achieved now by management holding more ownership in a firm than that found in previous studies. Managerial ownership also drives the capital structure as a nonlinear shape, but with a direction opposite to the shape of firm value. the results of simultaneous regressions suggest that managerial ownership affects capital structure, which in turn affects firm value. Capital structure is endogenously determined by bith firm value and managerial ownership; while managerial ownership is not endogenously determined by the other two variables.

Medical tourism: A conceptual framework for an innovation in global healthcare provision

© 2015, IGI Global. The purpose of this chapter is to establish a conceptual model that can potentially fill research gaps in the literature about medical tourism as an innovative concept in global healthcare provision by developing emerging economies as they are providing low cost alternatives in medical treatment at internationally accredited medical facilities to treat patients from developed countries. Major databases such as Ebscohost and Emerald have been used to search relevant literature. The literature on medical tourism is reviewed so as to understand the key drivers of medical tourism as well as research gaps in the existing literature. Three major drivers of medical tourism have been identified, namely cost, waiting time, and perceived quality. Further empirical research is needed to test the conceptual model in order to better understand what drives a decision to engage in medical tourism. This chapter makes three major contributions; firstly, the identification of the medical tourism literature from the service marketing and management perspectives; secondly, to propose a conceptual model representing innovation in medical tourism for global healthcare by developing emerging economies; thirdly, the identification of research gaps in the medical tourism literature through which future research can further the knowledge of why people travel to developing countries for medical treatment.

AMC: an adaptive multi-level cache algorithm in hybrid storage systems

Hybrid storage systems that consist of flash-based solid state drives (SSDs) and traditional disks are now widely used. In hybrid storage systems, there exists a two-level cache hierarchy that regard dynamic random access memory (DRAM) as the first level cache and SSD as the second level cache for disk storage. However, this two-level cache hierarchy typically uses independent cache replacement policies for each level, which makes cache resource management inefficient and reduces system performance. In this paper, we propose a novel adaptive multi-level cache (AMC) replacement algorithm in hybrid storage systems. The AMC algorithm adaptively adjusts cache blocks between DRAM and SSD cache levels using an integrated solution. AMC uses combined selective promote and demote operations to dynamically determine the level in which the blocks are to be cached. In this manner, the AMC algorithm achieves multi-level cache exclusiveness and makes cache resource management more efficient. By using real-life storage traces, our evaluation shows the proposed algorithm improves hybrid multi-level cache performance and also increases the SSD lifetime compared with traditional multi-level cache replacement algorithms.

A new transfer learning framework with application to model-agnostic multi-task learning

Learning from small number of examples is a challenging problem in machine learning. An effective way to improve the performance is through exploiting knowledge from other related tasks. Multi-task learning (MTL) is one such useful paradigm that aims to improve the performance through jointly modeling multiple related tasks. Although there exist numerous classification or regression models in machine learning literature, most of the MTL models are built around ridge or logistic regression. There exist some limited works, which propose multi-task extension of techniques such as support vector machine, Gaussian processes. However, all these MTL models are tied to specific classification or regression algorithms and there is no single MTL algorithm that can be used at a meta level for any given learning algorithm. Addressing this problem, we propose a generic, model-agnostic joint modeling framework that can take any classification or regression algorithm of a practitioner’s choice (standard or custom-built) and build its MTL variant. The key observation that drives our framework is that due to small number of examples, the estimates of task parameters are usually poor, and we show that this leads to an under-estimation of task relatedness between any two tasks with high probability. We derive an algorithm that brings the tasks closer to their true relatedness by improving the estimates of task parameters. This is achieved by appropriate sharing of data across tasks. We provide the detail theoretical underpinning of the algorithm. Through our experiments with both synthetic and real datasets, we demonstrate that the multi-task variants of several classifiers/regressors (logistic regression, support vector machine, K-nearest neighbor, Random Forest, ridge regression, support vector regression) convincingly outperform their single-task counterparts. We also show that the proposed model performs comparable or better than many state-of-the-art MTL and transfer learning baselines.

Social exclusion of Australian childless women in their reproductive years

Research suggests Australian childless women are at risk of pronatalism-driven social exclusion. This exploratory, mixed methods, cross-sectional study described and explored the social exclusion of Australian childless women aged 25 to 44 years, and asked: what are the nature and extent of social exclusion of childless women; and do the nature and extent of exclusion vary for different types of childless women? A total of 776 childless female Australian residents aged 25 to 44 years completed a self-administered questionnaire. Quantitative data were collected on childlessness types, indicators of exclusion and perceived stigmatisation and exclusion due to being childless. Data were analysed using descriptive statistics, One Way ANOVAs and Kruskal Wallis Analysis of Ranks. Qualitative data on childless women’s experiences were inductively thematically analysed. Findings suggest societal-level pronatalism drives exclusion of Australian childless women. While exclusion occurs in all domains of life, childless women experience more exclusion, and perceive more exclusion due to being childless, in the social and civic domains than the service and economic domains. Circumstantially and involuntarily childless women, followed by voluntarily childless women, perceive more exclusion due to being childless than undecided and future childed women. Experiences are influenced by the nature of women’s ‘deviance’ from pronatalism.