Structural and electronic properties of Al nanowires: an ab initio pseudopotential study

The stability and electronic structure of a single monatomic Al wire has been studied using the ab initio pseudopotential method. The Al wire undergoes two structural rearrangements under compression, i.e., zigzag configurations at angles of $140^o$ and $60^o$. The evolution of electronic structures of the Al chain as a function of structural phase transition has been investigated. The relationship between electronic structure and geometric stability is also discussed. The 2p bands in the Al nanowire are shown to play a critical role in its stability. The effects of density functionals (GGA and LDA) on cohesive energy and bond length of Al nanostructures (dimmer, chains, and monolayers) are also examined. The link between low dimensional 0D structure (dimmer) to high dimensional 3D bulk Al is estimated. An example of optimized tip-suspended finite atomic chain is presented to bridge the gap between hypothetical infinite chains and experimental finite chains.Comment: 11 pages, 5 figure

Applying Complexity Theory to Solve Hospitality Contrarian Case Conundrums: Illuminating Happy-Low and Unhappy-High Performing Frontline Service Employees

Purpose: This paper aims to advance a configural asymmetric theory of the complex antecedents to hospitality employee happiness-at-work and managers’ assessments of employees’ quality of work performance. The study transcends variable and case-level analyses to go beyond prior statistical findings of small-to-medium effect sizes of happiness–performance relationships; the study here identifies antecedent paths involving high-versus-low happy employees associating with high-versus-low managers’ assessments of these employees’ performances. Design/methodology/approach: The study merges data from surveys of employees (n = 247) and surveys completed by their managers (n = 43) and by using qualitative comparative analysis via the software program, fsQCA.com. The study analyzes data from Janfusan Fancyworld, the largest (in revenues and number of employees) tourism business group in Taiwan; Janfusan Fancyworld includes tourist hotels, amusement parks, restaurants and additional firms in related service sectors. Findings: The findings support the four tenets of configural analysis and theory construction: recognize equifinality of different solutions for the same outcome, test for asymmetric solutions, test for causal asymmetric outcomes for very high versus very low happiness and work performance and embrace complexity.Research limitations/implications: Additional research in other firms and additional countries is necessary to confirm the usefulness of examining algorithms for predicting very high (low) happiness and very high (low) quality of work performance. The implications are substantial that configural theory and research will resolve perplexing happiness–performance conundrums. Practical implications: The study provides useful case-level algorithms involving employees’ demographic characteristics and their assessments of work facet-specifics which are useful for explaining very high happiness-at-work and high quality of work performance (as assessed by managers) – as well as algorithms explaining very low happiness and very low quality of work performance. Originality/value: The study is the first to propose and test the tenets of configural theory in the context of hospitality frontline service employees’ happiness-at-work and managers’ assessments of these employees’ quality of work performances

Soliton with a Pion Field in the Global Color Symmetry Model

We calculate the property of the global color symmetry model soliton with the pion field being included explicitly. The calculated results indicate that the pion field provides a strong attraction so that the eigen-energy of a quark and the mass of a soliton reduce drastically, in contrast to those with only the sigma field.Comment: 15 pages, 2 figure

Fluorophore-Doped Core-Multishell Spherical Plasmonic Nanocavities: Resonant Energy Transfer towards a Loss Compensation

Cataloged from PDF version of article.Plasmonics exhibits the potential to break the diffraction limit and bridge the gap between electronics and photonics by routing and manipulating light at the nanoscale. However, the inherent and strong energy dissipation present in metals, especially in the near-infrared and visible wavelength ranges, significantly hampersthe applications in nanophotonics. Therefore, it is amajor challengetomitigatethe losses. One way to compensate the losses is to incorporate gain media into plasmonics. Here, we experimentally show that the incorporation of gain material into a local surface plasmonic system (Au/silica/silica dye core multishell nanoparticles) leads to a resonant energy transfer from the gain media to the plasmon. The optimized conditions for the largest loss compensation are reported. Both the coupling distance and the spectral overlap arethe key factorsto determinetheresulting energy transfer. Theinterplay of these factors leadsto a non-monotonous photoluminescence dependence as a function of the silica spacer shell thickness. Nonradiativetransferrate is increased by morethan 3 orders of magnitude attheresonant condition, which is key evidence of the strongest coupling occurring between the plasmon and the gain material

Linear response theory and transient fluctuation theorems for diffusion processes: a backward point of view

On the basis of perturbed Kolmogorov backward equations and path integral representation, we unify the derivations of the linear response theory and transient fluctuation theorems for continuous diffusion processes from a backward point of view. We find that a variety of transient fluctuation theorems could be interpreted as a consequence of a generalized Chapman-Kolmogorov equation, which intrinsically arises from the Markovian characteristic of diffusion processes

Enantioselective Decarboxylative Arylation of α-Amino Acids via the Merger of Photoredox and Nickel Catalysis

An asymmetric decarboxylative C_(sp)^3–C_(sp)^2 cross-coupling has been achieved via the synergistic merger of photoredox and nickel catalysis. This mild, operationally simple protocol transforms a wide variety of naturally abundant α-amino acids and readily available aryl halides into valuable chiral benzylic amines in high enantiomeric excess, thereby producing motifs found in pharmacologically active agents

Integromic analysis of genetic variation and gene expression identifies networks for cardiovascular disease phenotypes

Cataloged from PDF version of article.Background-Cardiovascular disease (CVD) reflects a highly coordinated complex of traits. Although genome-wide association studies have reported numerous single nucleotide polymorphisms (SNPs) to be associated with CVD, the role of most of these variants in disease processes remains unknown. Methods and Results-We built a CVD network using 1512 SNPs associated with 21 CVD traits in genome-wide association studies (at P <= 5x10(-8)) and cross-linked different traits by virtue of their shared SNP associations. We then explored whole blood gene expression in relation to these SNPs in 5257 participants in the Framingham Heart Study. At a false discovery rate <0.05, we identified 370 cis-expression quantitative trait loci (eQTLs; SNPs associated with altered expression of nearby genes) and 44 trans-eQTLs (SNPs associated with altered expression of remote genes). The eQTL network revealed 13 CVD-related modules. Searching for association of eQTL genes with CVD risk factors (lipids, blood pressure, fasting blood glucose, and body mass index) in the same individuals, we found examples in which the expression of eQTL genes was significantly associated with these CVD phenotypes. In addition, mediation tests suggested that a subset of SNPs previously associated with CVD phenotypes in genome-wide association studies may exert their function by altering expression of eQTL genes (eg, LDLR and PCSK7), which in turn may promote interindividual variation in phenotypes. Conclusions-Using a network approach to analyze CVD traits, we identified complex networks of SNP-phenotype and SNP-transcript connections. Integrating the CVD network with phenotypic data, we identified biological pathways that may provide insights into potential drug targets for treatment or prevention of CVD.(Circulation. 2015;131:536-549. DOI: 10.1161/CIRCULATIONAHA.114.010696.

Low power consumption mini rotary actuator with SMA wires

Shape memory alloys (SMAs) are smart materials widely used as actuators for their high power to weight ratio despite their well-known low energy efficiency and limited mechanical bandwidth. For robotic applications, SMAs exhibit limitations due to high power consumption and limited stroke, varying from 4% to 7% of the total length. Hysteresis, during the contraction and extension cycle, requires a complex control algorithm. On the positive side, the small size and low weight are eminently suited for the design of mini actuators for robotic platforms. This paper describes the design and construction of a light weight and low power consuming mini rotary actuator with on-board contact-less position and force sensors. The design is specifically intended to reduce (i) energy consumption, (ii) dimensions of the sensory system, and (iii) provide a simple control without any need for SMA characterisation. The torque produced is controlled by on-board force sensors. Experiments were performed to investigate the energy consumption and performance (step and sinusoidal angle profiles with a frequency varying from 0.5 to 10 Hz and maximal amplitude of 15?). We describe a transient capacitor effect related to the SMA wires during the sinusoidal profile when the active SMA wire is powered and the antagonist one switched-off, resulting in a transient current time varying from 300 to 400 ms

Lowest-lying Tetra-Quark Hadrons in Anisotropic Lattice QCD

We present a detailed study of lowest-lying $q^{2}\bar{q}^{2}$ hadrons in quenched improved anisotropic lattice QCD. Using the $\pi\pi$ and diquark-antidiquark local and smeared operators, we attempt to isolate the signal for $I(J^{P})=0(0^{+}), 2(0^{+})$ and $1(1^{+})$ states in two flavour QCD. In the chiral limit of light-quark mass region, the lowest scalar $4q$ state is found to have a mass, $m^{I=0}_{4q}=927(12)$ MeV, which is slightly lower than the experimentally observed $f_{0}(980)$. The results from our variational analysis do not indicate a signature of a tetraquark resonance in I=1 and I=2 channels. After the chiral extrapolation the lowest $1(1^{+})$ state is found to have a mass, $m^{I=1}_{4q}=1358(28)$ MeV. We analysed the static $4q$ potential extracted form a tetraquark Wilson loop and illustrated the behaviour of the $4q$ state as a bound state, unbinding at some critical diquark separation. From our analysis we conclude that scalar $4q$ system appears as a two-pion scattering state and that there is no spatially-localised $4q$ state in the light-quark mass region.Comment: 9 pages, 10 figure

Performance evaluation of tourism websites&apos; information quality of four global destination brands

Some tourists only have a slight idea of where they want to go on a holiday when planning starts. Such tourists or their travel partners are likely to look for information for making a final travel decision. As the web becomes an increasingly popular information source, tourism destination websites can play a critical role in destination choice. A rubric for comparing tourism websites put forward by Dion and Woodside (2010) is used and ideas for enhancing the rubric are introduced utilizing a growing literature. Comparisons are made for the tourism websites of Hong Kong, Shanghai, Beijing, and Taipei. Analysis involves considering websites&apos; quality and usefulness. The study indicates that Hong Kong&apos;s site is best while Beijing has the most room for improvement. The paper concludes with implications of the research for website analysis. The discussion includes contributions to the value of criteria for websites found in the literature but not covered in an information-quality performance rubric