bluuebunny/crossref_metadata_2025 huggingface dataset:
Semi-quantitative analysis of the depth distribution of radiative recombination centers in silicon power devices by cross-sectional cathodoluminescence
Authors: Sugie R. , Inoue K. , Yoshikawa M.
Published: August 2012

A procedure to obtain the semi-quantitative depth distribution of radiative recombination centers in silicon power devices has been developed using cross-sectional cathodoluminescence (CL) by considering the nonradiative recombination on the surface of devices. Sharp luminescent peaks at 1.018 eV (W or I1), 1.040 eV (X or I3), and 0.790 eV (C) and a broad band about 0.90–1.05 eV in addition to near-band-edge emission were observed in the n-drift layer of the electron-irradiated lifetime-controlled punch-through insulated gate bipolar transistors using cross-sectional CL measurements. The semi-quantitative depth distributions of X, W, and C centers were obtained by the procedure. Each had a maximum value at the midpoint of the n-drift region, although electrons conventionally used to control carrier lifetime in power devices penetrated the entire device. One of the possible mechanisms for these distributions is the interaction of the X, W, and C centers with other point-like defects and impurities near the surface and the interface. The minority carrier (hole) diffusion length and the reduced recombination velocity in the devices are also extracted by this procedure.
Comparison of self-consistent field convergence acceleration techniques
Authors: Garza Alejandro J. , Scuseria Gustavo E.
Published: August 2012

The recently proposed ADIIS and LIST methods for accelerating self-consistent field (SCF) convergence are compared to the previously proposed energy-DIIS (EDIIS) + DIIS technique. We here show mathematically that the ADIIS functional is identical to EDIIS for Hartree-Fock wavefunctions. Convergence failures of EDIIS + DIIS reported in the literature are not reproduced with our codes. We also show that when correctly implemented, the EDIIS + DIIS method is generally better than the LIST methods, at least for the cases previously examined in the literature. We conclude that, among the family of DIIS methods, EDIIS + DIIS remains the method of choice for SCF convergence acceleration.
Study of optical anisotropy in nonpolar and semipolar AlGaN quantum well deep ultraviolet light emission diode
Authors: Wang Chang-Pei , Wu Yuh-Renn
Published: August 2012

This paper analyzes the optical polarization characteristics and internal quantum efficiency (IQE) of an AlGaN based polar, nonpolar, and semipolar deep ultra-violet (UV) light emitting diode (LED). A one dimensional model is used to solve drift-diffusion, Poisson equations, and 6 × 6 k·p Schrodinger equations to investigate band structure and emission characteristics. The light emission polarization ratios of c-plane, nonpolar, and semipolar AlGaN based deep UV LEDs with different Al compositions and injection current were studied. The study shows that the optical polarization of the c-plane AlGaN based deep UV LED is dominated by the out-plane polarization as the Al composition increases. For nonpolar and semipolar structures, the light polarization direction is mainly dominated by the in-plane polarized light which is good for the surface emitting. Finally, influences of the IQE by changing the p-type activation energy, growth orientation, and nonradiatve lifetime are studied in this paper.
Donor behavior of Sb in ZnO
Authors: Liu H. Y. , Izyumskaya N. , Avrutin V. , Özgür Ü. , Yankovich A. B. , Kvit A. V. , Voyles P. M. , Morkoç H.
Published: August 2012

Electrical behavior of Sb in ZnO:Sb layers doped in a wide concentration range was studied using temperature dependent Hall effect measurements. The layers were grown by plasma-enhanced molecular beam epitaxy, and the Sb concentration was changed by varying the Sb flux, resulting in electron concentrations in the range of 1016 to nearly 1020 cm−3. Upon annealing, the electron concentration increased slightly and more notable was that the electron mobility significantly improved, reaching a room-temperature value of 110 cm2/V s and a low-temperature value of 145 cm2/V s, close to the maximum of ∼155 cm2/V s set by ionized impurity scattering. Hall data and structural data suggest that Sb predominantly occupies Zn sublattice positions and acts as a shallow donor in the whole concentration range studied. In the layers with high Sb content (∼1 at. %), acceptor-type compensating defects (possibly Sb on oxygen sites and/or point-defect complexes involving SbO) are formed. The increase of electron concentration with increasing oxygen pressure and the increase in ZnO:Sb lattice parameter at high Sb concentrations suggest that acceptors involving SbO rather than SbZn-2VZn complexes are responsible for the compensation of the donors.
An audit of pneumococcal and hepatitis vaccination in an outpatient HIV clinic
Authors: Hunter Michael G. , Post Jeffrey J.
Published: August 2012

Background HIV-positive adults are at risk of vaccine preventable infections including Streptococcus pneumoniae, hepatitis A virus (HAV) and hepatitis B virus (HBV). Uptake of immunisations in HIV patients is suboptimal despite evidence of efficacy. Methods: An audit was made of the vaccination records in 200 adult HIV-positive regular clinic attendees, with a CD4+ count >200 cells μL–1. Results: Medical records or laboratory data revealed that 10% had been vaccinated against S. pneumoniae; 74% were immune or immunised against HAV; 40% had evidence of natural infection with HBV and 84% of nonimmune patients had been vaccinated. Conclusions: Strategies to improve vaccine uptake are required.
Small molecule inhibitors of Smoothened ciliary localization and ciliogenesis
Authors: Wu Victoria M. , Chen Steven C. , Arkin Michelle R. , Reiter Jeremy F.
Published: August 2012

Vertebrate Hedgehog (Hh) signals involved in development and some forms of cancer, such as basal cell carcinoma, are transduced by the primary cilium, a microtubular projection found on many cells. A critical step in vertebrate Hh signal transduction is the regulated movement of Smoothened (Smo), a seven-transmembrane protein, to the primary cilium. To identify small molecules that interfere with either the ciliary localization of Smo or ciliogenesis, we undertook a high-throughput, microscopy-based screen for compounds that alter the ciliary localization of YFP-tagged Smo. This screen identified 10 compounds that inhibit Hh pathway activity. Nine of these Smo antagonists (SA1–9) bind Smo, and one (SA10) does not. We also identified two compounds that inhibit ciliary biogenesis, which block microtubule polymerization or alter centrosome composition. Differential labeling of cell surface and intracellular Smo pools indicates that SA1–7 and 10 specifically inhibit trafficking of intracellular Smo to cilia. In contrast, SA8 and 9 recruit endogenous Smo to the cilium in some cell types. Despite these different mechanisms of action, all of the SAs inhibit activation of the Hh pathway by an oncogenic form of Smo, and abrogate the proliferation of basal cell carcinoma-like cancer cells. The SA compounds may provide alternative means of inhibiting pathogenic Hh signaling, and our study reveals that different pools of Smo move into cilia through distinct mechanisms.
Differential Regulation of ER Ca2+ Uptake and Release Rates Accounts for Multiple Modes of Ca2+-induced Ca2+ Release
Authors: Albrecht Meredith A. , Colegrove Stephen L. , Friel David D.
Published: August 2012

The ER is a central element in Ca2+ signaling, both as a modulator of cytoplasmic Ca2+ concentration ([Ca2+]i) and as a locus of Ca2+-regulated events. During surface membrane depolarization in excitable cells, the ER may either accumulate or release net Ca2+, but the conditions of stimulation that determine which form of net Ca2+ transport occurs are not well understood. The direction of net ER Ca2+ transport depends on the relative rates of Ca2+ uptake and release via distinct pathways that are differentially regulated by Ca2+, so we investigated these rates and their sensitivity to Ca2+ using sympathetic neurons as model cells. The rate of Ca2+ uptake by SERCAs (JSERCA), measured as the t-BuBHQ-sensitive component of the total cytoplasmic Ca2+ flux, increased monotonically with [Ca2+]i. Measurement of the rate of Ca2+ release (JRelease) during t-BuBHQ-induced [Ca2+]i transients made it possible to characterize the Ca2+ permeability of the ER (\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\overline{\mathrm{P}}_{\mathrm{ER}}\) \end{document}), describing the activity of all Ca2+-permeable channels that contribute to passive ER Ca2+ release, including ryanodine-sensitive Ca2+ release channels (RyRs) that are responsible for CICR. Simulations based on experimentally determined descriptions of JSERCA, \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\overline{\mathrm{P}}_{\mathrm{ER}}\) \end{document}, and of Ca2+ extrusion across the plasma membrane (Jpm) accounted for our previous finding that during weak depolarization, the ER accumulates Ca2+, but at a rate that is attenuated by activation of a CICR pathway operating in parallel with SERCAs to regulate net ER Ca2+ transport. Caffeine greatly increased the [Ca2+] sensitivity of \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\overline{\mathrm{P}}_{\mathrm{ER}}\) \end{document}, accounting for the effects of caffeine on depolarization-evoked [Ca2+]i elevations and caffeine-induced [Ca2+]i oscillations. Extending the rate descriptions of JSERCA, \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\overline{\mathrm{P}}_{\mathrm{ER}}\) \end{document}, and Jpm to higher [Ca2+]i levels shows how the interplay between Ca2+ transport systems with different Ca2+ sensitivities accounts for the different modes of CICR over different ranges of [Ca2+]i during stimulation.
Delineation of glutamate pathways and secretory responses in pancreatic islets with β-cell–specific abrogation of the glutamate dehydrogenase
Authors: Vetterli Laurène , Carobbio Stefania , Pournourmohammadi Shirin , Martin-del-Rio Rafael , Skytt Dorte M. , Waagepetersen Helle S. , Tamarit-Rodriguez Jorge , Maechler Pierre
Published: August 2012

In pancreatic β-cells, glutamate dehydrogenase (GDH) modulates insulin secretion, although its function regarding specific secretagogues is unclear. This study investigated the role of GDH using a β-cell–specific GDH knockout mouse model, called βGlud1−/−. The absence of GDH in islets isolated from βGlud1–/–mice resulted in abrogation of insulin release evoked by glutamine combined with 2-aminobicyclo[2.2.1]heptane-2-carboxylic acid or l-leucine. Reintroduction of GDH in βGlud1–/–islets fully restored the secretory response. Regarding glucose stimulation, insulin secretion in islets isolated from βGlud1–/–mice exhibited half of the response measured in control islets. The amplifying pathway, tested at stimulatory glucose concentrations in the presence of KCl and diazoxide, was markedly inhibited in βGlud1–/–islets. On glucose stimulation, net synthesis of glutamate from α-ketoglutarate was impaired in GDH-deficient islets. Accordingly, glucose-induced elevation of glutamate levels observed in control islets was absent in βGlud1–/–islets. Parallel biochemical pathways, namely alanine and aspartate aminotransferases, could not compensate for the lack of GDH. However, the secretory response to glucose was fully restored by the provision of cellular glutamate when βGlud1–/–islets were exposed to dimethyl glutamate. This shows that permissive levels of glutamate are required for the full development of glucose-stimulated insulin secretion and that GDH plays an indispensable role in this process.
Alternative splicing results in RET isoforms with distinct trafficking properties
Authors: Richardson Douglas S. , Rodrigues David M. , Hyndman Brandy D. , Crupi Mathieu J. F. , Nicolescu Adrian C. , Mulligan Lois M.
Published: August 2012

RET encodes a receptor tyrosine kinase that is essential for spermatogenesis, development of the sensory, sympathetic, parasympathetic, and enteric nervous systems and the kidneys, as well as for maintenance of adult midbrain dopaminergic neurons. RET is alternatively spliced to encode multiple isoforms that differ in their C-terminal amino acids. The RET9 and RET51 isoforms display unique levels of autophosphorylation and have differential interactions with adaptor proteins. They induce distinct gene expression patterns, promote different levels of cell differentiation and transformation, and play unique roles in development. Here we present a comprehensive study of the subcellular localization and trafficking of RET isoforms. We show that immature RET9 accumulates intracellularly in the Golgi, whereas RET51 is efficiently matured and present in relatively higher amounts on the plasma membrane. RET51 is internalized faster after ligand binding and undergoes recycling back to the plasma membrane. This differential trafficking of RET isoforms produces a more rapid and longer duration of signaling through the extracellular-signal regulated kinase/mitogen-activated protein kinase pathway downstream of RET51 relative to RET9. Together these differences in trafficking properties contribute to some of the functional differences previously observed between RET9 and RET51 and establish the important role of intracellular trafficking in modulating and maintaining RET signaling.
Quiescent fibroblasts are protected from proteasome inhibition–mediated toxicity
Authors: Legesse-Miller Aster , Raitman Irene , Haley Erin M. , Liao Albert , Sun Lova L. , Wang David J. , Krishnan Nithya , Lemons Johanna M. S. , Suh Eric J. , Johnson Elizabeth L. , Lund Benjamin A. , Coller Hilary A.
Published: August 2012

Proteasome inhibition is used as a treatment strategy for multiple types of cancers. Although proteasome inhibition can induce apoptotic cell death in actively proliferating cells, it is less effective in quiescent cells. In this study, we used primary human fibroblasts as a model system to explore the link between the proliferative state of a cell and proteasome inhibition–mediated cell death. We found that proliferating and quiescent fibroblasts have strikingly different responses to MG132, a proteasome inhibitor; proliferating cells rapidly apoptosed, whereas quiescent cells maintained viability. Moreover, MG132 treatment of proliferating fibroblasts led to increased superoxide anion levels, juxtanuclear accumulation of ubiquitin- and p62/SQSTM1-positive protein aggregates, and apoptotic cell death, whereas MG132-treated quiescent cells displayed fewer juxtanuclear protein aggregates, less apoptosis, and higher levels of mitochondrial superoxide dismutase. In both cell states, reducing reactive oxygen species with N-acetylcysteine lessened protein aggregation and decreased apoptosis, suggesting that protein aggregation promotes apoptosis. In contrast, increasing cellular superoxide levels with 2-methoxyestradiol treatment or inhibition of autophagy/lysosomal pathways with bafilomycin A1 sensitized serum-starved quiescent cells to MG132-induced apoptosis. Thus, antioxidant defenses and the autophagy/lysosomal pathway protect serum-starved quiescent fibroblasts from proteasome inhibition–induced cytotoxicity.
Autoinhibition of the formin Cappuccino in the absence of canonical autoinhibitory domains
Authors: Bor Batbileg , Vizcarra Christina L. , Phillips Martin L. , Quinlan Margot E.
Published: August 2012

Formins are a conserved family of proteins known to enhance actin polymerization. Most formins are regulated by an intramolecular interaction. The Drosophila formin, Cappuccino (Capu), was believed to be an exception. Capu does not contain conserved autoinhibitory domains and can be regulated by a second protein, Spire. We report here that Capu is, in fact, autoinhibited. The N-terminal half of Capu (Capu-NT) potently inhibits nucleation and binding to the barbed end of elongating filaments by the C-terminal half of Capu (Capu-CT). Hydrodynamic analysis indicates that Capu-NT is a dimer, similar to the N-termini of other formins. These data, combined with those from circular dichroism, suggest, however, that it is structurally distinct from previously described formin inhibitory domains. Finally, we find that Capu-NT binds to a site within Capu-CT that overlaps with the Spire-binding site, the Capu-tail. We propose models for the interaction between Spire and Capu in light of the fact that Capu can be regulated by autoinhibition.
Amphibacillus marinus sp. nov., a member of the genus Amphibacillus isolated from marine mud
Authors: Ren Biao , Yang Na , Wang Jian , Ma Xiao-Long , Wang Qian , Xie Feng , Guo Hui , Liu Zhi-Heng , Pugin Benoît , Zhang Li-Xin
Published: August 2012

A Gram-positive, spore-forming, rod-shaped bacterium, designated J1T was isolated from deep-sea mud collected from the South China Sea and subjected to polyphasic taxonomic investigation. Phylogenetic analysis based on 16S rRNA gene sequences revealed that J1T clustered with the type strains of

Amphibacillus cookii

,

Amphibacillus sediminis

and

Amphibacillus jilinensis

and exhibited a range of similarity of 93.9–97.0 % to members of the genus

Amphibacillus

. The DNA G+C content was 36.7 mol%. Chemotaxonomic analysis showed no quinones, and the cell wall contained meso-diaminopimelic acid as the diagnostic diamino acid for strain J1T. The major cellular fatty acids were iso-C15 : 0 and anteiso-C15 : 0. Strain J1T was positive for catalase activity and negative for oxidase activity. On the basis of phylogenetic position and phenotypic properties, strain J1T represents a novel species of the genus

Amphibacillus

and the name Amphibacillus marinus sp. nov. is proposed. The type strain is J1T ( = CGMCC 1.10434T = JCM 17099T).
Modulation of foot-and-mouth disease virus pH threshold for uncoating correlates with differential sensitivity to inhibition of cellular Rab GTPases and decreases infectivity in vivo
Authors: Vázquez-Calvo Ángela , Caridi Flavia , Rodriguez-Pulido Miguel , Borrego Belén , Sáiz Margarita , Sobrino Francisco , Martín-Acebes Miguel A.
Published: August 2012

The role of cellular Rab GTPases that govern traffic between different endosome populations was analysed on foot-and-mouth disease virus (FMDV) infection. Changes of viral receptor specificity did not alter Rab5 requirement for infection. However, a correlation between uncoating pH and requirement of Rab5 for infection was observed. A mutant FMDV with less acidic uncoating pH threshold was less sensitive to inhibition of Rab5, whereas another mutant with more acidic requirements was more sensitive to inhibition of Rab5. On the contrary, opposed correlations between uncoating pH and dependence of Rab function were observed upon expression of dominant-negative forms of Rab7 or 11. Modulation of uncoating pH also reduced FMDV virulence in suckling mice. These results are consistent with FMDV uncoating inside early endosomes and indicate that displacements from optimum pH for uncoating reduce viral fitness in vivo.
Diffusion Limitations in Root Uptake of Cadmium and Zinc, But Not Nickel, and Resulting Bias in the Michaelis Constant
Authors: Degryse Fien , Shahbazi Afsaneh , Verheyen Liesbeth , Smolders Erik
Published: August 2012

It has long been recognized that diffusive boundary layers affect the determination of active transport parameters, but this has been largely overlooked in plant physiological research. We studied the short-term uptake of cadmium (Cd), zinc (Zn), and nickel (Ni) by spinach (Spinacia oleracea) and tomato (Lycopersicon esculentum) in solutions with or without metal complexes. At same free ion concentration, the presence of complexes, which enhance the diffusion flux, increased the uptake of Cd and Zn, whereas Ni uptake was unaffected. Competition effects of protons on Cd and Zn uptake were observed only at a very large degree of buffering, while competition of magnesium ions on Ni uptake was observed even in unbuffered solutions. These results strongly suggest that uptake of Cd and Zn is limited by diffusion of the free ion to the roots, except at very high degree of solution buffering, whereas Ni uptake is generally internalization limited. All results could be well described by a model that combined a diffusion equation with a competitive Michaelis-Menten equation. Direct uptake of the complex was estimated to be a major contribution only at millimolar concentrations of the complex or at very large ratios of complex to free ion concentration. The true K  m for uptake of Cd  2+ and Zn  2+ was estimated at <5 nm, three orders of magnitude smaller than the K  m measured in unbuffered solutions. Published Michaelis constants for plant uptake of Cd and Zn likely strongly overestimate physiological ones and should not be interpreted as an indicator of transporter affinity.
The impact of demographic characteristics of users on patterns of usage on search engines and OPAC
Authors: Kumar Shiv
Published: August 2012

Purpose

The purpose of this paper is to investigate the influence of user demographic characteristics on the impact of usage of search engines, particularly Google, with special regard to OPAC in the context of an Indian university setting.

Design/methodology/approach

This study is based on a survey where the tool of investigation was a close‐ended questionnaire that was distributed among respondents, was self‐filled and returned. The data, thus collected, were processed on MS‐Excel and subsequently on the SPSS statistical package which was used specifically for the analysis of results and also for producing cross‐tables. The Chi‐square test was applied to determine the comparability or the existence of any relationship between the impact of web searching on OPAC use and demographic characteristics of individual searchers.

Findings

The study found significant differences between OPAC usage patterns and demographic characteristics of user categories and age groups. Significant variations were noticed among user age groups for awareness about differences between the inner‐workings of the OPAC and web search engines. A significant relationship was found between male and female users vis‐à‐vis their viewpoint after unsuccessful searches. Certain variations were also observed among academic majors with regard to perceptions of users after failed searches. Interestingly, no significant differences were observed between actions of users after unsuccessful searches and the parameters pertaining to their age groups, categories, academic majors and gender.

Originality/value

This is in all probability one of the first empirical studies to be published on the influence of demographic characteristics of users on the impact of web searching with respect to OPAC use. These characteristics have been observed to definitively impact upon the influence of web searching in some limited activities.
Plugging the “whole”: librarians as interdisciplinary facilitators
Authors: Knapp Jeffrey A.
Published: August 2012

Purpose

The purpose of this paper is to examine some of the obstacles to interdisciplinary research and examine some ways that academic librarians can help to overcome them.

Design/methodology/approach

A broad review of the literature of the social sciences was reviewed for descriptions of difficulties that interdisciplinary researchers encounter. General developments in librarianship from library literature were then applied as a starting point for discussing ways that librarians can provide important services to interdisciplinary scholars.

Findings

Librarians, as “meta‐scholars”, can provide useful services to scholars engaging in interdisciplinary research.

Social implications

Interdisciplinary research has shown great potential for problem‐solving, being focused more on a problem than with disciplinary distinctions. This is a worthy area for librarians to target with their skills and services.

Originality/value

This is a discussion of ways that librarians can break into new roles and responsibilities, and simultaneously strengthen their profile at a time when some expect librarianship to fade away.
Studies of the contribution of alternating electromagnetic ﬁelds toward material fatigue in 100Cr6
Authors: Holweger Walter , Wolf Marcus , Walther Frank , Trojahn Werner , Mütze Annette , Kunzmann Jan , Schreiber Jürgen , Mayer Joachim , Reichelt Manuela
Published: August 2012

Purpose

The purpose of this paper is to show how controlled exposure of electromagnetic fields toward bearing steel vulnerates the microstructure. The ability of Barkhausen Noise signal processing is used for detecting phenomena such as dislocation and subgrain formation processes as the beginning of later failures.

Design/methodology/approach

A Barkhausen noise signal measurement equipment is used for detecting subsurface distress of 100Cr6 as a function of the applied electromagnetic and mechanical stress. Barkhausen noise signal is mathematically processed by use of fractal dimension analysis.

Findings

The paper cleary reveals significant impact of electromagnetic field in junction with mechanical loading. Electromagnetic impact depends on the magnitude of the field.

Research limitations/implications

Research limitations are given by the fact that in real field applications, e.g. wind power plants, bearings are exposed by multiple influences and the methodology is not applicable to those conditions.

Practical implications

The methodology can be applied to real field applications in condition monitoring systems. Up to now, no reasonable on‐line measurement is in use determining sub surface fatigue phenomena. The paper hence, reveals the possibility to raise condition monitoring into a new perspective.

Originality/value

The use of Barkhausen noise signal processing, as presented here, is original with respect to real field applications, such as wind power plants with a high demand in condition monitoring, especially off‐shore plants.
Development and modification of Fe and FeCu nanoparticles and tribological analysis of the lubricants with nano‐suspensions
Authors: Padgurskas Juozas , Prosyčevas Igoris , Rukuiža Raimundas , Kreivaitis Raimondas , Kupčinskas Artūras
Published: August 2012

Purpose

The purpose of this paper is to investigate the possibility of using the iron nanoparticles and iron nanoparticles coated with copper layer as additives to base oils.

Design/methodology/approach

Fe and Fe+Cu nanoparticles were synthesized by a reduction modification method and added to mineral oil. The size and structure of prepared nanoparticles were characterized by SEM, TEM, XRF, AAS and XRD analysis. Tribological properties of modified lubricants were evaluated on a four‐ball machine in a model of sliding friction pairs.

Findings

Spectral and microscopy analysis evidently displayed the formation of Fe and Fe+Cu nanoparticles in suspensions of colloidal solutions and oil. The size of formed nanoparticles was in 15‐50 nm range. Tribological experiments show good lubricating properties of oils modified with Fe and Fe+Cu nanoparticles: higher wear resistance (55 per cent and 46 per cent accordingly) and lower friction coefficient (30 per cent and 26 per cent accordingly). The tests show that nanoparticles provide decreasing tendency of friction torque during the operation of friction pair.

Originality/value

The paper demonstrates that iron nanoparticles and iron nanoparticles coated with copper layer, not only reduce the wear and friction decrease of friction pairs, but possibly also can create layer in oil which separates two friction surfaces and have some self‐organisation properties.
Determination of tribological properties at CuSn10 alloy journal bearings by experimental and means of artificial neural networks method
Authors: Sadık Ünlü Bekir , Durmuş Hülya , Meriç Cevdet
Published: August 2012

Purpose

It is important to know the friction coefficient and wear loss for determination of tribological conditions at journal bearings. Tribological events that influence wear and its variations affect experimental results. The purpose of this paper is to determine friction coefficient and wear loss at CuSn10 alloy radial bearings by a new approach. In experiments, effects of bearings have been examined at dry and lubricated conditions and at different loads and velocities.

Design/methodology/approach

In this study, friction coefficient and wear losses of journal and bearing have been determined by a new approach with a radial journal bearing test rig and artificial neural networks (ANNs) method. The ANN typifies a learning technique that enables the hidden input‐output relationship to be mapped accurately. Bronze‐based materials have been used as bearing material. Effects of friction coefficient and wear losses have been examined at same load and velocity and at dry and lubricated conditions.

Findings

The results obtained in ANN application are close to friction test results for dry and lubricated conditions. Therefore, by using trained ANN values, the intermediate results that were not obtained in the tests can be calculated. Experimental studies will be increased and research with ANN will be continued.

Originality/value

By using trained ANN values, the intermediate results that were not obtained in the tests can be calculated. The training finished on 30 min whereas experimental study had continued day after day.
The surface roughness effects of transverse patterns on the Hopf bifurcation behaviors of short journal bearings
Authors: Lin Jaw‐Ren
Published: August 2012

Purpose

On the ground of the Hopf bifurcation theory derived by Hassard et al., the purpose of this paper is to investigate the weakly nonlinear dynamics of transverse rough‐surface short journal bearings.

Design/methodology/approach

By application of the stochastic model of rough surfaces, developed by Christensen and Tonder, the roughness effects of transverse surface patterns on the bifurcation behaviors close to the Hopf bifurcation point are investigated.

Findings

It is found that the dynamic behavior of transverse rough‐surface short journal bearings can display Hopf bifurcation phenomena. Comparing with the case of isotropic rough‐surface bearing by Lin, under the same parameters, the effects of transverse surface roughness provide a reduced sub‐critical Hopf bifurcation region as well as an increased super‐critical Hopf bifurcation region. In addition, the effects of transverse surface roughness result in a lower stability‐threshold critical speed for both the sub‐critical bifurcation profile and the super‐critical bifurcation profile.

Originality/value

The present study, associated with the results of Hopf bifurcation regions and periodic orbits, can provide useful information for engineers when the transverse surface roughness effects and the bifurcation behavior are considered in a journal bearing system.
Attitudes to employment law and the consequent impact of legislation on employment relations practice
Authors: Curran Deirdre , Quinn Mary
Published: August 2012

Purpose

The purpose of this paper is to explore attitudes to employment law and the consequent impact of legislation on Irish employment relations practice.

Design/methodology/approach

The paper adopts a comparative approach using two separate pieces of employment law governing race equality, and employee information and consultation, respectively. Semi‐structured interviews with key informants are the main data source, augmented in the case of the information and consultation legislation by focus groups in individual workplaces.

Findings

The empirical evidence presented suggests that legislation is not the primary initiator of change. In the case of race equality the market was found to be a key determinant of practice (termed “market‐prompted voluntarism”). However, it is argued that regulation can influence change in organisations, depending on the complex dynamic between a number of contingencies, including the aspect of employment being regulated, the presence of supportive institutions, and organisation‐specific variables.

Practical implications

The comparative findings in this research allow some important inferences to be made regarding the use of law to mandate change in employment relations practice. They, in turn, provide useful lessons for future policy makers, managers, trade unionists and workers.

Originality/value

This paper is unique in its comparison of two separate pieces of legislation. In both cases considered, the legislation was prompted by EU Directives, and the obligation on member states to transpose these Directives into national law. The findings suggest that readiness for legislation, based on length of national debate and acceptance of the underlying concept, can influence its impact. The concept of equality seems to have gained widespread acceptance since the debate provoked by the 1948 Universal Declaration of Human Rights. However, understanding and acceptance of the concept of employee voice has been much less pronounced in the Anglo‐Saxon world.
At‐risk student averse: risk management and accountability
Authors: Vasquez Heilig Julian , Young Michelle , Williams Amy
Published: August 2012

Purpose

The prevailing theory of action underlying accountability is that holding schools and students accountable will increase educational output. While accountability's theory of action intuitively seemed plausible, at the point of No Child Left Behind's national implementation, little empirical research was available to either support or critique accountability claims or to predict the long‐term impact of accountability systems on the success of at‐risk students and the schools that served them. The purpose of this paper is to analyze the work and perceptions of school teachers and leaders as they seek to meet the requirements of educational accountability.

Design/methodology/approach

Interviews with 89 administrators, staff and teachers revealed a variety of methods utilized to manage risks associated with low test scores and accountability ratings.

Findings

The findings reported in this paper challenge the proposition that accountability improves the educational outcomes of at‐risk students and indicates that low‐performing Texas high schools, when faced with the press of accountability, tend to mirror corporate risk management processes, with unintended consequences for at‐risk students. Low‐scoring at‐risk students were often viewed as liabilities by school personnel who, in their scramble to meet testing thresholds and accountability goals, were at‐risk student averse – implementing practices designed to “force kids out of school.”

Originality/value

In this paper, the authors use theory and research on risk management to analyze the work and perceptions of school teachers and leaders as they seek to meet the requirements of educational accountability. This paper is among the first to use this particular perspective to conceptualize and understand the practices of educational organizations with regards to the treatment of at‐risk students attending low‐performing high schools in the midst of accountability.
Contrasting effects of instructional leadership practices on student learning in a high accountability context
Authors: Lee Moosung , Walker Allan , Ling Chui Yuk
Published: August 2012

Purpose

The purpose of this paper is to examine the effects of different dimensions of instructional leadership on student learning in Hong Kong secondary schools, whose broader institutional contexts are critically characterized by high accountability policy environments.

Design/methodology/approach

This study utilizes standardized test scores collected from (n=2,037) students in 42 secondary schools and data collected from key staff's perceptions of leadership practices, to investigate two dimensions of instructional leadership, which are conceptually interdependent but distinctive – i.e. instructional management and direct supervision of instruction. A cross‐level interaction analysis of hierarchical linear modeling was employed to investigate the effects of the two dimensions of instructional leadership on student learning.

Findings

Leadership practices focused on instructional management were found to enhance student learning by boosting the positive effect of students’ attachment to their school on academic achievement. In contrast, leadership practices related to direct supervision of instruction were found to undermine student learning by weakening the positive effect of student perceptions of school attachment on academic performance when other school‐ and student‐level characteristics are held constant.

Originality/value

The paper reveals the contrasting effects of instructional leadership as a multi‐dimensional construct which is central in the current education reform agenda, rooted in accountability‐oriented policy of Hong Kong. It draws a number of implications for principal instructional leadership in Hong Kong Schools as they deal with demands for external accountability.
Investigative management and consumer research on the internet
Authors: Lugosi Peter , Janta Hania , Watson Pamela
Published: August 2012

Purpose

This paper aims to introduce the notion of investigative research on the internet (IRI) and conceptualise its processes through the principle of streaming. It seeks to discuss the similarities and differences between IRI and netnography and considers various aspects of the IRI process, including site selection, sampling, data collection and analysis.

Design/methodology/approach

Investigative internet‐based research uses the techniques of ethnography and netnography, including variations of participant observation and analysis of visual and textual material. Three international empirical cases are used to illustrate the application of IRI and streaming in research on international workers, consumer cultures and on emerging business phenomena.

Findings

IRI has a number of potential applications for hospitality management academics and practitioners. Streaming can help to understand the processes involved in conducting netnographic research, and streaming is a more appropriate way to conceptualise some internet‐based studies that do not conform to netnographic or ethnographic ideals.

Research limitations/implications

The three empirical cases highlight the processes of streaming in practice, which can be applied elsewhere. Principal limitations are the ethical dimensions of conducting undisclosed research and the sampling bias resulting from adopting an unobtrusive role and focusing on active internet users.

Practical implications

The paper highlights several issues, identified through streaming, that can be used to design human resource, marketing and operational strategies.

Originality/value

The paper demonstrates the application of streaming. Streaming can help researchers conduct netnographic studies; it is also a more appropriate way to describe broader types of investigative internet research. Moreover, it demonstrates the applicability of streaming in research on hospitality management and public policy issues.
Using focus groups as a tool to develop a hospitality work‐life research study
Authors: O'Neill John W.
Published: August 2012

Purpose

This paper seeks to describe how the results of the qualitative research method of focus groups may be used as conceptual data at the onset of a research study to inform researchers regarding relevant issues for future more in‐depth quantitative study.

Design/methodology/approach

Seven focus group sessions with a total of 50 participants were conducted, each focus group with six to eight participants. All focus groups included the homogeneous participants of new entrants to the hospitality industry. Focus group questions were inductive and naturalistic and centered on career expectations and work‐life issues. Sessions averaged 1 hour and 15 minutes and were conducted by trained graduate students.

Findings

The paper suggests that long, unpredictable hours create both work‐related and non‐work stress. Further, there is general agreement regarding the stressors and benefits associated with working in the hospitality industry.

Research limitations/implications

Limitations include the use of senior, hospitality management majors, all of whom had hospitality industry employment experience, but some of whom had fewer than 1,000 hours of such experience.

Originality/value

This work illustrates how focus groups may fit into a larger research study involving the hospitality industry. This work also explores the common issue, but understudied topic of work‐life balance in the hotel industry. In so doing, it provides greater understanding of the issue to researchers.
Beyond consensus: an alternative use of Delphi enquiry in hospitality research
Authors: Paraskevas Alexandros , Saunders Mark N.K.
Published: August 2012

Purpose

This paper's aim is to critically review the use of Delphi techniques in qualitative research for utilising “expert” opinions and to explore through a detailed example how Policy Delphi can be used by hospitality researchers as an alternative to the more widely used Normative Delphi.

Design/methodology/approach

The paper reflects on the research methodology of a project that explored organisational crisis signals detection using Policy Delphi with a criterion sample comprising 16 senior hotel executives involved in crisis management.

Findings

The main methodological concerns regarding Delphi are the definition of consensus, the expertise of the panel, its lack of scientific rigour, and – due to its lack of uniformity – reliability and validity of findings. Policy Delphi by default addresses the first since it does not seek consensus and can, through its design and execution, address the remaining concerns.

Research limitations/implications

Carefully designed Policy Delphi can offer a powerful research tool for exploratory research in hospitality, particularly for development of policies and strategies within an organisation. Unlike Normative Delphi, it is not intended as a decision making tool, but rather as a tool to generate options and suggest alternative courses of action for consideration.

Originality/value

The paper presents a valuable research tool that has evaded the attention of many hospitality researchers offering an illustrative example of its use in exploratory research to deliver credible, transferable and confirmable findings.
A framework for designing sustainable telemedicine information systems in developing countries
Authors: Mayoka Kituyi G. , Rwashana Agnes S. , Mbarika Victor W. , Isabalija Stephen
Published: August 2012

Purpose

The purpose of this paper is to develop a framework for designing sustainable telemedicine information systems in developing countries.

Design/methodology/approach

Both quantitative and qualitative research methods were used. Primary data were collected from two hospitals in Uganda using a self‐administered questionnaire and an interview guide. Descriptive statistics were used to analyze survey data, while content analysis method was used to analyze interview responses. The framework was developed based on Hevner et al.'s design science framework.

Findings

The key requirements for designing sustainable telemedicine information systems in developing countries were identified as the need for speed, ease of use and affordability.

Research limitations/implications

This study was theoretical in nature. Although primary data were used, the researchers were unable to carry out a series of practical tests of this framework with prototype systems on a cross‐section of users.

Practical implications

Design and sustainability of telemedicine information systems is still a big challenge to most developing countries, despite its wide usage in the developed countries. While various telemedicine frameworks exist, not much has been done to adequately address the issue of design for sustainability. This paper proposes an appropriate framework that will guide telemedicine information systems designers on designing telemedicine systems that are sustainable in local conditions of developing countries.

Originality/value

The main contribution of this paper is in the area of information systems design for sustainability, from a developing country perspective. The paper also extends on the constructs of design science research theory and shows how they can be applied in information systems design and evaluation.
An innovative information hiding technique utilizing cumulative peak histogram regions
Authors: Al‐Omari Faruq A. , Al‐Khaleel Osama D. , Rayyashi Ghassan A. , Ghwanmeh Sameh H.
Published: August 2012

Purpose

The purpose of this paper is to develop an innovative information hiding algorithm.

Design/methodology/approach

The proposed algorithm is based on image histogram statistics. Cumulative‐peak histogram regions are utilized to hide multiple bits of the secret message by performing histogram bin substitution. The embedding capacity, otherwise known as payload, and peak signal to noise ratio (PSNR), as well as security, are the main metrics used to evaluate the performance of the proposed algorithm.

Findings

According to the obtained results, the proposed algorithm shows high embedding capacity and security at comparable PSNR compared with existing hiding information techniques.

Originality/value

The simplicity, security, random distribution of embedding pixels, and on‐demand high capacity are the key advantages of the proposed approach.
Mergers and acquisitions process: the use of corporate culture analysis
Authors: Weber Yaakov , Yedidia Tarba Shlomo
Published: August 2012

Purpose

The purpose of this paper is to advance cross‐cultural management during mergers and acquisitions (M&A), an issue that remains poorly understood despite a large body of literature accumulated over many years of study and experience.

Design/methodology/approach

Based on literature review and case studies of both successful and unsuccessful companies, this paper clarifies the concept, the assessment and the use of corporate culture and its dimensions during all mergers and acquisitions stages, and as such shows its role as an important and influential milestone in the international business environment exploration.

Findings

The paper arrives at the conclusion that the enduring paradox of the high rate of M&A failure vs the growing activity of M&A may be due to lack of synchronized activities of all merger stages.

Practical implications

The paper presents frameworks and managerial tools that can help researchers and practitioners conduct better corporate culture assessment during all stages of the M&A, including screening, planning, and negotiation, and enhance the effectiveness of interventions carried out during post‐merger integration process.

Originality/value

The paper offers insights into corporate culture and its impact during pre‐merger stage, negotiation, and the post‐merger integration process.