bluuebunny/crossref_metadata_2025 huggingface dataset:
Groundwater‐dependent vegetation: Quantifying the groundwater subsidy
Authors: Lowry Christopher S. , Loheide Steven P.
Published: June 2010

The typical stratigraphy of riparian ecosystems consists of fine‐grained overbank deposits overlying coarser‐grained materials. Plants within these regions rely on soil moisture in the fine‐grained sediments as well as supplemental groundwater for root water uptake. The additional water available as a result of shallow water table conditions is defined here as groundwater subsidy and is found to be a significant contribution to root water uptake. Work presented here quantifies the effect of groundwater subsidy on root water uptake as a result of variations in the soil thickness of the upper fine‐grained sediments, rate of water table decline, and maximum water table depth. Variations in soil thickness and water table decline regimes produce a complex response with respect to both the rate of groundwater subsidy and the cumulative groundwater subsidy. These simulated regimes are analogs to environmental scenarios in riparian ecosystems that result from stream incision, soil erosion, and climate change. These results have implications for identifying ecosystems most susceptible to future change as well as those most amenable to restoration.
Greenhouse gas mitigation by agricultural intensification
Authors: Burney Jennifer A. , Davis Steven J. , Lobell David B.
Published: June 2010

As efforts to mitigate climate change increase, there is a need to identify cost-effective ways to avoid emissions of greenhouse gases (GHGs). Agriculture is rightly recognized as a source of considerable emissions, with concomitant opportunities for mitigation. Although future agricultural productivity is critical, as it will shape emissions from conversion of native landscapes to food and biofuel crops, investment in agricultural research is rarely mentioned as a mitigation strategy. Here we estimate the net effect on GHG emissions of historical agricultural intensification between 1961 and 2005. We find that while emissions from factors such as fertilizer production and application have increased, the net effect of higher yields has avoided emissions of up to 161 gigatons of carbon (GtC) (590 GtCO
2
e) since 1961. We estimate that each dollar invested in agricultural yields has resulted in 68 fewer kgC (249 kgCO
2
e) emissions relative to 1961 technology ($14.74/tC, or ∼$4/tCO
2
e), avoiding 3.6 GtC (13.1 GtCO
2
e) per year. Our analysis indicates that investment in yield improvements compares favorably with other commonly proposed mitigation strategies. Further yield improvements should therefore be prominent among efforts to reduce future GHG emissions.
B-cell signaling networks reveal a negative prognostic human lymphoma cell subset that emerges during tumor progression
Authors: Irish Jonathan M. , Myklebust June H. , Alizadeh Ash A. , Houot Roch , Sharman Jeff P. , Czerwinski Debra K. , Nolan Garry P. , Levy Ronald
Published: June 2010

Human tumors contain populations of both cancerous and host immune cells whose malignant signaling interactions may define each patient's disease trajectory. We used multiplexed phospho-flow cytometry to profile single cells within human follicular lymphoma tumors and discovered a subpopulation of lymphoma cells with impaired B cell antigen receptor (BCR) signaling. The abundance of BCR-insensitive cells in each tumor negatively correlated with overall patient survival. These lymphoma negative prognostic (LNP) cells increased as tumors relapsed following chemotherapy. Loss of antigen receptor expression did not explain the absence of BCR signaling in LNP tumor cells, and other signaling responses were intact in these cells. Furthermore, BCR signaling responses could be reactivated in LNP cells, indicating that BCR signaling is not missing but rather specifically suppressed. LNP cells were also associated with changes to signaling interactions in the tumor microenvironment. Lower IL-7 signaling in tumor infiltrating T cells was observed in tumors with high LNP cell counts. The strength of signaling through T cell mediator of B cell function CD40 also stratified patient survival, particularly for those whose tumors contained few LNP cells. Thus, analysis of cell–cell interactions in heterogeneous primary tumors using signaling network profiles can identify and mechanistically define new populations of rare and clinically significant cells. Both the existence of these LNP cells and their aberrant signaling profiles provide targets for new therapies for follicular lymphoma.
Nanoparticle synthesis using high-powered pulse-modulated induction thermal plasma
Authors: Tanaka Yasunori , Nagumo T , Sakai H , Uesugi Y , Sakai Y , Nakamura K
Published: June 2010

Nanoparticle synthesis was performed using the high-powered pulse-modulated induction thermal plasma (PMITP) technique to study the effect of coil current modulation on synthesized nanoparticles. This is the first paper to present a summary of results of TiO2 nanoparticle synthesis using high-power Ar–O2 PMITP at 20 kW. The synthesized particles were analysed using field emission scanning electron microscopy and x-ray diffractometry. In addition, optical emission spectroscopy was used during nanoparticle synthesis experiments to measure TiO spectra and to determine the time-averaged vibrational and rotational temperatures of TiO in the reaction chamber. The results showed that the PMITP produced smaller nanoparticles and a narrower size distribution of particles. Moreover, PMITP provided a lower temperature region in the reaction chamber downstream of the plasma torch than such regions in non-modulated thermal plasmas.
New understandings and achievements from independent-injector drive experiments on HIT-SI
Authors: Ennis D.A. , Victor B.S. , Wrobel J.S. , Akcay C. , Jarboe T.R. , Marklin G.J. , Nelson B.A. , Smith R.J.
Published: June 2010

The Helicity Injected Torus-Steady Inductive (HIT-SI) experiment investigates steady inductive helicity injection with the aim of forming and sustaining a high-beta equilibrium in a spheromak geometry using two semi-toroidal injectors. Results of experiments with unequal helicity injection rates produced the highest spheromak current (38 kA), current amplification (I
tor/I
inj_quad ≈ 2) and poloidal flux amplification (ψpol/ψinj_quad > 6) to date. Single-injector operations establish a preferred direction of generated spheromak current for each injector depending on the sign of the injected helicity and its orientation relative to the confinement volume. Yet, the HIT-SI injectors prefer to drive opposing spheromak currents because they are mounted on opposite sides of the confinement volume. Single-injector operations also eliminate the spontaneous spheromak current flipping observed during dual-injector operations.
Assessing the Effects of Acupuncture by Comparing Needling the Hegu Acupoint and Needling Nearby Nonacupoints by Spectral Analysis of Microcirculatory Laser Doppler Signals
Authors: Hsiu Hsin , Hsu Wei-Chen , Hsu Chia-Liang , Huang Shih-Min
Published: June 2010

We aimed to assess the effects of acupuncture by analyzing the frequency content of skin blood‐flow signals simultaneously recorded at the Hegu acupoint and two nearby nonacupoints following acupuncture stimulation (AS). Laser Doppler flowmetry (LDF) signals were measured in male healthy volunteers in two groups of experiments: needling the Hegu acupoint (n = 13) and needling a nearby nonacupoint (control experiment; n = 10). Each experiment involved recording a 20 min baseline‐data sequence and two sets of effects data recorded 0–20 and 50–70 min after stopping AS. Wavelet transform with Morlet mother wavelet was applied to the measured LDF signals. Needling the Hegu acupoint significantly increased the blood flow, significantly decreased the relative energy contribution at 0.02–0.06 Hz and significantly increased the relative energy contribution at 0.4–1.6 Hz at Hegu, but induced no significant changes at the nonacupoints. Also, needling a nearby nonacupoint had no effect in any band at any site. This is the first time that spectral analysis has been used to investigate the microcirculatory blood‐flow responses induced by AS, and has revealed possible differences in sympathetic nerve activities between needling the Hegu acupoint and its nearby nonacupoint. One possible weakness of the present design is that different De‐Qi feelings following AS could lead to nonblind experimental setup, which may bias the comparison between needling Hegu and its nearby nonacupoint. Our results suggest that the described noninvasive method can be used to evaluate sympathetic control of peripheral vascular activity, which might be useful for studying the therapeutic effects of AS.
Fifteen observations on the structure of energy-minimizing gaits in many simple biped models
Authors: Srinivasan Manoj
Published: June 2010

A popular hypothesis regarding legged locomotion is that humans and other large animals walk and run in a manner that minimizes the metabolic energy expenditure for locomotion. Here, using numerical optimization and supporting analytical arguments, I obtain the energy-minimizing gaits of many different simple biped models. I consider bipeds with point-mass bodies and massless legs, with or without a knee, with or without a springy tendon in series with the leg muscle and minimizing one of many different ‘metabolic cost’ models—correlated with muscle work, muscle force raised to some power, the Minetti–Alexander quasi-steady approximation to empirical muscle metabolic rate (from heat and ATPase activity), a new cost function called the ‘generalized work cost’Cghaving some positivity and convexity properties (and includes the Minetti–Alexander cost and the work cost as special cases), and generalizations thereof. For many of these models, walking-like gaits are optimal at low speeds and running-like gaits at higher speeds, so a gait transition is optimal. Minimizing the generalized work costCgappears mostly indistinguishable from minimizing muscle work for all the models. Inverted pendulum walking and impulsive running gaits minimize the work cost, generalized work costsCgand a few other costs for the springless bipeds; in particular, a knee-torque-squared cost, appropriate as a simplified model for electric motor power for a kneed robot biped. Many optimal gaits had symmetry properties; for instance, the left stance phase was identical to the right stance phases. Muscle force–velocity relations and legs with masses have predictable qualitative effects, if any, on the optima. For bipeds with compliant tendons, the muscle work-minimizing strategies have close to zero muscle work (isometric muscles), with the springs performing all the leg work. These zero work gaits also minimize the generalized work costsCgwith substantial additive force or force rate costs, indicating that a running animal's metabolic cost could be dominated by the cost of producing isometric force, even though performing muscle work is usually expensive. I also catalogue the many differences between the optimal gaits of the various models. These differences contain information that might help us develop models that better predict locomotion data. In particular, for some biologically plausible cost functions, the presence or absence of springs in series with muscles has a large effect on both the coordination strategy and the absolute cost; the absence of springs results in more impulsive (collisional) optimal gaits and the presence of springs leads to more compliant optimal gaits. Most results are obtained for specific speed and stride length combinations close to preferred human behaviour, but limited numerical experiments show that some qualitative results extend to other speed-stride length combinations as well.
Quiescence: a mechanism for escaping the effects of drug on cell populations
Authors: Alarcón Tomás , Jensen Henrik Jeldtoft
Published: June 2010

We point out that a simple and generic strategy in order to lower the risk for extinction consists in developing a dormant stage in which the organism is unable to multiply but may die. The dormant organism is protected against the poisonous environment. The result is to increase the survival probability of the entire population by introducing a type of zero reproductive fitness. This is possible, because the reservoir of dormant individuals act as a buffer that can cushion fatal fluctuations in the number of births and deaths, which without the dormant population would have driven the entire population to extinction.
Desertibacter roseus gen. nov., sp. nov., a gamma radiation-resistant bacterium in the family Rhodospirillaceae, isolated from desert sand
Authors: Liu Ming , Dai Jun , Liu Yufeng , Cai Feng , Wang Yaqiong , Rahman Erkin , Fang Chengxiang
Published: June 2010

A Gram-negative, rod-shaped, strictly aerobic bacterium, strain 2622T, was isolated from gamma-irradiated soil sampled from the Taklimakan desert in Xinjiang, China. Phylogenetic analyses showed that strain 2622T formed a distinct lineage in the family Rhodospirillaceae and shared 91.7 and 90.1 % 16S rRNA gene sequence similarity with its closest relatives, the type strains of Skermanella xinjiangensis and Skermanella aerolata, respectively. The DNA G+C content of strain 2622T was 71.4 mol% and the isoprenoid quinone was ubiquinone Q-10. Based on phenotypic and chemotaxonomic data and phylogenetic analysis, strain 2622T is considered to represent a novel species of a new genus in the family Rhodospirillaceae, for which the name Desertibacter roseus gen. nov., sp. nov. is proposed. The type strain of Desertibacter roseus is strain 2622T ( = CCTCC AB 208152T  = KCTC 22436T).
Hansschlegelia zhihuaiae sp. nov., isolated from a polluted farmland soil
Authors: Wen Ya , Huang Xing , Zhou Yu , Hong Qing , Li Shunpeng
Published: June 2010

A novel Gram-negative, aerobic, coccoid-shaped strain designated S 113T was isolated from a polluted-soil sample collected in Jiangsu Province, China. A polyphasic taxonomic study including phylogenetic analysis based on the 16S rRNA gene sequence and determination of phenotypic characteristics was performed on the new isolate. The highest 16S rRNA gene sequence similarity was 96.8 %, with Hansschlegelia plantiphila S1
T. The predominant respiratory quinone was ubiquinone 10 (Q-10). The major fatty acids were C18 : 1ω7c and C16 : 0. The G+C content of the DNA was about 65.7 mol%. DNA–DNA hybridization experiments showed 44.9 % relatedness for strain S 113T with its closest relative, H. plantiphila NCIMB 14035T. The dominant phospholipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine and phosphatidylcholine. The results of our polyphasic taxonomic analysis indicate that strain S 113T represents a novel species within the genus Hansschlegelia, for which the name Hansschlegelia zhihuaiae sp. nov. is proposed. The type strain is S 113T ( = DSM 18984T  = CCTCC AB 206143T  = KCTC 12880T).
Paracoccus isoporae sp. nov., isolated from the reef-building coral Isopora palifera
Authors: Chen Ming-Hui , Sheu Shih-Yi , Chen Chaolun Allen , Wang Jih-Terng , Chen Wen-Ming
Published: June 2010

A bacterial strain, designated SW-3T, was isolated from the reef-building coral Isopora palifera, from Southern Taiwan, and was characterized by using a polyphasic taxonomic approach. Cells of strain SW-3T were Gram-reaction-negative, aerobic, rod-shaped and motile by means of monopolar flagella and formed cream–white colonies. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain SW-3T belonged to the genus Paracoccus and its most closely related neighbours were P. aestuarii B7T, P. homiensis DD-R11T, P. marinus KKL-A5T, P. denitrificans DSM 413T and P. zeaxanthinifaciens R-1512T, with sequence similarities of 96.8, 96.6, 96.1 , 95.8 and 94.9 %, respectively. Strain SW-3T exhibited optimal growth at 25–30 °C and pH 9–10 and in 3–5 % (w/v) NaCl. The predominant cellular fatty acid was summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c; 75 %). The major respiratory quinone was Q-10. The polar lipid profile consisted of a mixture of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine and several uncharacterized polar lipids. The DNA G+C content of strain SW-3T was 63.7 mol%. The results of physiological and biochemical tests allowed clear phenotypic differentiation of this isolate from recognized species of the genus Paracoccus. It is evident from the genotypic, phenotypic and chemotaxonomic data that strain SW-3T represents a novel species of the genus Paracoccus, for which the name Paracoccus isoporae sp. nov. is proposed. The type strain is SW-3T ( = LMG 25205T  = BCRC 17967T).
Jishengella endophytica gen. nov., sp. nov., a new member of the family Micromonosporaceae
Authors: Xie Qing-Yi , Wang Cheng , Wang Rong , Qu Zhi , Lin Hai-Peng , Goodfellow Michael , Hong Kui
Published: June 2010

A novel endophytic actinomycete, designated strain 202201T, was isolated from an Acanthus illicifolius root collected from the mangrove reserve zone in Hainan Province, China. Phylogenetic analysis based on 16S rRNA gene sequences suggested that strain 202201T fell within the family Micromonosporaceae. The strain formed an extensively branched substrate mycelium, which carried uneven warty-surfaced spores. Cell walls of strain 202201T contained meso-diaminopimelic acid and xylose, mannose, arabinose, ribose and glucose were detected as whole-cell sugars. The acyl type of the cell-wall polysaccharides was glycolyl. The major menaquinones were MK-9(H4), MK-9(H6), MK-9(H8) and MK-10(H4). The polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylinositol mannoside and phosphatidylserine. The major cellular fatty acids were 10-methyl-C17 : 0, iso-C15 : 0, iso-C16 : 0 and C17 : 1ω8c. The DNA G+C content was 72.3 mol%. On the basis of the morphological and chemotaxonomic characteristics, phylogenetic analysis and characteristic patterns of 16S rRNA gene signature nucleotides, strain 202201T ( = CGMCC 4.5597T  = DSM 45430T) represents a novel species of a new genus within the family Micromonosporaceae, for which the name Jishengella endophytica gen. nov., sp. nov. is proposed.
Streptohalobacillus salinus gen. nov., sp. nov., a moderately halophilic, Gram-positive, facultative anaerobe isolated from subsurface saline soil
Authors: Wang Xiaowei , Xue Yanfen , Ma Yanhe
Published: June 2010

A Gram-stain-positive, rod-shaped, non-sporulating, motile and moderately halophilic bacterium, designated strain H96B60T, was isolated from a saline soil sample of the Qaidam basin, China. The strain was facultatively anaerobic. Major end products formed from glucose fermentation were acetate, ethanol and lactic acid. The cell-wall peptidoglycan contained meso-diaminopimelic acid as the diagnostic diamino acid. The isoprenoid quinone component was menaquinone-6 (MK-6). The predominant cellular fatty acids were C16 : 0, anteiso-C13 : 0 and anteiso-C15 : 0. The genomic DNA G+C content of strain H96B60T was 36.2 mol%. Phylogenetic analysis based on comparative 16S rRNA gene sequences indicated that strain H96B60T represented a novel phyletic lineage within the family Bacillaceae and was related most closely to Halolactibacillus species (96.1–96.4 % similarity). Based on the phenotypic, chemotaxonomic and phylogenetic data presented, strain H96B60T is considered to represent a novel species of a new genus, for which the name Streptohalobacillus salinus gen. nov., sp. nov. is proposed. The type strain of Streptohalobacillus salinus is H96B60T ( = DSM 22440T  = CGMCC 1.7733T).
Involvement of hydrogenases in the formation of highly catalytic Pd(0) nanoparticles by bioreduction of Pd(II) using Escherichia coli mutant strains
Authors: Deplanche Kevin , Caldelari Isabelle , Mikheenko Iryna P. , Sargent Frank , Macaskie Lynne E.
Published: June 2010

Escherichia coli produces at least three [NiFe] hydrogenases (Hyd-1, Hyd-2 and Hyd-3). Hyd-1 and Hyd-2 are membrane-bound respiratory isoenzymes with their catalytic subunits exposed to the periplasmic side of the membrane. Hyd-3 is part of the cytoplasmically oriented formate hydrogenlyase complex. In this work the involvement of each of these hydrogenases in Pd(II) reduction under acidic (pH 2.4) conditions was studied. While all three hydrogenases could contribute to Pd(II) reduction, the presence of either periplasmic hydrogenase (Hyd-1 or Hyd-2) was required to observe Pd(II) reduction rates comparable to the parent strain. An E. coli mutant strain genetically deprived of all hydrogenase activity showed negligible Pd(II) reduction. Electron microscopy suggested that the location of the resulting Pd(0) deposits was as expected from the subcellular localization of the particular hydrogenase involved in the reduction process. Membrane separation experiments established that Pd(II) reductase activity is membrane-bound and that hydrogenases are required to initiate Pd(II) reduction. The catalytic activity of the resulting Pd(0) nanoparticles in the reduction of Cr(VI) to Cr(III) varied according to the E. coli mutant strain used for the initial bioreduction of Pd(II). Optimum Cr(VI) reduction, comparable to that observed with a commercial Pd catalyst, was observed when the bio-Pd(0) catalytic particles were prepared from a strain containing an active Hyd-1. The results are discussed in the context of economic production of novel nanometallic catalysts.
Mitotic chromosome condensation mediated by the retinoblastoma protein is tumor-suppressive
Authors: Coschi Courtney H. , Martens Alison L. , Ritchie Kieran , Francis Sarah M. , Chakrabarti Subrata , Berube Nathalie G. , Dick Frederick A.
Published: June 2010

Condensation and segregation of mitotic chromosomes is a critical process for cellular propagation, and, in mammals, mitotic errors can contribute to the pathogenesis of cancer. In this report, we demonstrate that the retinoblastoma protein (pRB), a well-known regulator of progression through the G1 phase of the cell cycle, plays a critical role in mitotic chromosome condensation that is independent of G1-to-S-phase regulation. Using gene targeted mutant mice, we studied this aspect of pRB function in isolation, and demonstrate that it is an essential part of pRB-mediated tumor suppression. Cancer-prone Trp53−/− mice succumb to more aggressive forms of cancer when pRB's ability to condense chromosomes is compromised. Furthermore, we demonstrate that defective mitotic chromosome structure caused by mutant pRB accelerates loss of heterozygosity, leading to earlier tumor formation in Trp53+/− mice. These data reveal a new mechanism of tumor suppression, facilitated by pRB, in which genome stability is maintained by proper condensation of mitotic chromosomes.
The Mg-Chelatase H Subunit ofArabidopsisAntagonizes a Group of WRKY Transcription Repressors to Relieve ABA-Responsive Genes of Inhibition
Authors: Shang Yi , Yan Lu , Liu Zhi-Qiang , Cao Zheng , Mei Chao , Xin Qi , Wu Fu-Qing , Wang Xiao-Fang , Du Shu-Yuan , Jiang Tao , Zhang Xiao-Feng , Zhao Rui , Sun Hai-Li , Liu Rui , Yu Yong-Tao , Zhang Da-Peng
Published: June 2010

The phytohormone abscisic acid (ABA) plays a vital role in plant development and response to environmental challenges, but the complex networks of ABA signaling pathways are poorly understood. We previously reported that a chloroplast protein, the magnesium-protoporphyrin IX chelatase H subunit (CHLH/ABAR), functions as a receptor for ABA in Arabidopsis thaliana. Here, we report that ABAR spans the chloroplast envelope and that the cytosolic C terminus of ABAR interacts with a group of WRKY transcription factors (WRKY40, WRKY18, and WRKY60) that function as negative regulators of ABA signaling in seed germination and postgermination growth. WRKY40, a central negative regulator, inhibits expression of ABA-responsive genes, such as ABI5. In response to a high level of ABA signal that recruits WRKY40 from the nucleus to the cytosol and promotes ABAR–WRKY40 interaction, ABAR relieves the ABI5 gene of inhibition by repressing WRKY40 expression. These findings describe a unique ABA signaling pathway from the early signaling events to downstream gene expression.
Abrasive behavior of discontinuous fiber reinforced polypropylene material
Authors: Subramanian C. , Senthilvelan S.
Published: June 2010

Purpose

The purpose of this paper is to understand the influence of reinforced fiber length over material‐plastic energy of deformation, clogging, crystallinity, and correlates with the friction and wear behavior of polypropylene (PP) composites under multi‐pass abrasive condition. Also to identify wear mechanisms of glass fiber reinforced PP materials under various abrasive grit sizes and normal loads.

Design/methodology/approach

Multi‐pass abrasive wear tests were performed for unreinforced, short, and long glass fiber reinforced PP (LFPP) on a pin on disc machine under three different normal loads and two different abrasive grit sizes for a constant sliding velocity. Measured wear volume was correlated with the plastic energy of deformation by carrying out a constant load indentation test using servo hydraulic fatigue test system. Clogging behavior of test materials was examined with the aid of online wear measurement and wear morphology. Test materials crystallinity was estimated with the aid of X‐ray diffraction investigation and correlated with abrasive wear performance.

Findings

Fiber reinforcement in a PP material is found to improve the plastic deformation energy and crystallinity which results in improved abrasive resistance of the material. Increase in reinforced fiber length is found to improve the material cohesive energy and hence the wear resistance. Reinforcement is found to alter the material clogging behavior under multi‐pass condition. Fiber reinforcement is found to reduce the material coefficient of friction, and increase in reinforced fiber length further reduces the frictional coefficient.

Research limitations/implications

Friction wear tests using pin on disc equipment is carried out in the present investigation. However, in practice, part geometry may not be always equivalent to simple pin on disc configuration.

Practical implications

The paper's investigation results could help to improve the utilization of LFPP material in many structural applications.

Originality/value

Influence of reinforced fiber length over multi‐pass abrasive wear performance of thermoplastic material, and online wear measurement to substantiate clogging behavior is unique in the present multi‐pass abrasive investigation.
Laser gas‐assisted nitriding of steel: residual stress analysis
Authors: Yilbas Bekir , Arif A.F.M. , Karatas Cihan , Abdul Aleem B.J. , Tabet Nouer
Published: June 2010

Purpose

The laser nitriding process is involved with high temperature heating and high cooling rates. This, in turn, results in high levels of thermal stresses in the heated region. Moreover, the residual stress in the heated region remains high after the completion of the heating process, which limits the application of the laser nitriding process. The purpose of this paper is to investigate thermal stresses development and residual stress levels in the nitrided region.

Design/methodology/approach

The microstructural changes and residual stress development in the laser gas‐assisted nitrided zone are examined. Finite element modeling is carried out to predict temperature and stress fields in the laser nitrided layer. The indentation tests and X‐ray diffraction (XRD) technique are used to determine the residual stress levels while previously derived analytical formula is used to predict the residual stress levels in the nitrided region.

Findings

The residual stress predicted attains values within 230 MPa, which remains almost uniform in the nitrided layer, except in the surface region. In this case, residual stress reduces slightly due to the low temperature gradient developed in this region and the unconstrained expansion of the free surface. When comparing the residual stress predicted with the measurement results as obtained from the XRD technique as well as the indentation tests, all the results are in reasonably good agreement. The small discrepancies between the experimental data and predictions are attributed to the assumptions made in the model study and the measurement errors.

Research limitations/implications

The depth of nitrided layer is limited 60 μm. This limits the applicability of the coating for high wearing rates.

Practical implications

The nitrided surface improves the surface properties of steel, which can be used in industry more efficiently.

Originality/value

The paper describes an original model study on stress formation, an experiment for surface characterization and estimation of residual stress formation and contains new findings.
Wear properties of magnesium matrix composites reinforced with SiO2 particles
Authors: Aydin Mustafa , Findik Fehim
Published: June 2010

Purpose

The purpose of this paper is to improve the wear resistance and tribological properties of magnesium and its alloys in order to apply them to the friction components.

Design/methodology/approach

Wear test, microhardness measurements, X‐ray diffraction (XRD), optical and electron microscopy examinations were applied.

Findings

The ceramic SiO2, which has different particle‐sized reinforced pure Mg‐SiO2 composites, is produced by powder metallurgy using high ball milling, pressing and sintering. Mg2Si and MgO intermetallic phases produced by powder metallurgy in the Mg‐SiO2 composite are dispersed as homogeneous into the Mg matrix. Mg‐SiO2 composites exhibited a lower wear rate than the unreinforced pure magnesium specimens. Despite the pure Mg, the wear resistance of the composite is 61 per cent and the wear volume decrease with reducing SiO2 particle size. The hardness of the composite is increased in a ratio of 70 per cent with the distribution of the Mg2Si and MgO phases into the Mg matrix.

Practical implications

In this paper, pure Mg powder with purity of 99.9 per cent and SiO2 powders with a mean particle size of −500, −250, −125, −75 and −10 μm are mixed by mechanical alloying. The wear behaviour of Mg‐SiO2 composite, with the different particle‐sized composites dispersed with Mg2Si and MgO intermetallic phases under dry friction condition is studied. The microstructural and mechanical properties of composite material samples are determined by differential scanning calorimeter, XRD, microhardness, optical and scanning electron microscopy tests.

Originality/value

SiO2 particles distributed in the matrix are effective to improve hardness and wear resistance when contacting counter materials. In the present study, the magnesium powders with different particle size SiO2 powders are mechanically alloyed with a Turbola Spex 80000 mixer.
Talent on demand?
Authors: Burbach Ralf , Royle Tony
Published: June 2010

Purpose

As the interest in talent management (TM) gathers momentum, this paper aims to unravel how talent is managed in multinational corporations, what factors mediate the talent management process and what computerised systems may contribute to the management of talent.

Design/methodology/approach

The study employs a single case study but multiple units of analysis approach to elucidate the factors pertaining to the transmission and use of talent management practices across the German and Irish subsidiaries of a US multinational corporation. Primary data for this study derive from a series of in‐depth interviews with key decision makers, which include managers at various levels in Germany, Ireland and The Netherlands.

Findings

The findings suggest that the diffusion of, and success of, talent management practices is contingent on a combination of factors, including stakeholder involvement and top level support, micro‐political exchanges, and the integration of talent management with a global human resource information system. Furthermore, the discussion illuminates the utility and limitations of Cappelli's “talent on demand” framework.

Research limitations/implications

The main limitation of this research is the adoption of a single case study method. As a result, the findings may not be applicable to a wider population of organisations and subsidiaries. Additional research will be required to substantiate the relevance of these findings in the context of other subsidiaries of the same and other corporations.

Practical implications

This paper accentuates a number of practical implications. Inter alia, it highlights the complex nature of institutional factors affecting the talent management process and the potential efficacy of a human resource information system in managing talent globally.

Originality/value

The paper extends the body of knowledge on the transfer of talent management practices in the subsidiaries of multinational corporations. The discussion presented herein may engender further academic debate on the talent management process in the academic and practitioner communities. The link between talent management and the use of human resource information systems established by this research may be of particular interest to human resource practitioners.
Age, discrimination, and achievement motives
Authors: Rabl Tanja
Published: June 2010

Purpose

The aim of this paper is to challenge the person‐related aspect of the stereotype that older employees are unmotivated. In an overall model, it seeks to examine how age, perceived age discrimination, and perceived organizational support relate to each other and how they affect the achievement motives' hope of success and fear of failure.

Design/methodology/approach

Data were collected in six large German enterprises using a standardized questionnaire. The sample included 631 older employees aged 50 to 64 and 624 younger employees aged 30 to 40. For the data analysis, PLS structural equation modeling was used.

Findings

The results showed that older employees were more strongly affected by age discrimination than their younger colleagues. Perceived age discrimination, in turn, led to less perceived organizational support and a higher fear of failure. Age, in contrast, was not substantially related to achievement motives. Thus, the stereotype of unmotivated older employees is not justified.

Practical implications

The findings outline the central role of perceived age discrimination. Thus, with an increasingly aging workforce, organizations have to amplify their anti‐discrimination efforts by applying suitable human resource management and leadership practices.

Originality/value

This paper contributes to the literature by challenging a stereotype common in Western societies and examining the achievement motives of older employees. Moreover, it tries to shed light on the organization's role regarding the perception of discriminating and non‐supporting environments.
Personality and career decisiveness
Authors: Gunkel Marjaana , Schlaegel Christopher , Langella Ian M. , Peluchette Joy V.
Published: June 2010

Purpose

The purpose of this paper is two‐fold: first, the degree to which career adaptability, career optimism, and career knowledge predict career decisiveness in China, Germany, and the US is to be examined; second, the effect of the five personality traits on the determinants of career decisiveness, on career decisiveness, and on the relation between career decisiveness and its determinants in the three countries is to be investigated.

Design/methodology/approach

A survey was conducted using a structured questionnaire. The sample consists of 555 business students from three countries: China (196), Germany (210), and the USA (149). A two‐stage OLS regression analysis was applied for assessing the relation between career decisiveness, its determinants, and the personality traits.

Findings

The results show that personality traits have direct and moderating effects on career decisiveness and its antecedents. In addition, the influence of personality and the antecedents of career decisiveness differ in the three countries examined.

Research limitations/implications

The conclusions of this study may be subject to several limitations that suggest further possibilities for empirical research, e.g. the study does not examine the influence of cultural traits on career decisiveness, its determinants, and their relation.

Practical implications

The identified cross‐country differences lead to the need for diverse career counseling for students with different personalities in different countries.

Originality/value

So far research on students' career decisiveness has focused only on national samples. The explorative paper examines the influence of personality traits on business students' career decisiveness in three countries.
Performance measurement of high yield bond mutual funds
Authors: Trainor William J.
Published: June 2010

Purpose

The high yield debt market has evolved into a $1 trillion market over the last 25 years. The purpose of this paper is to analyze the risk‐adjusted performance of individual mutual funds that investors use to invest in this asset class.

Design/methodology/approach

Conditional excess returns are calculated for individual high yield bond mutual funds. Performance persistence over time is measured and size, asset growth, asset duration, the expense ratio, turnover, and manager tenure are used to determine if differences across funds can be explained.

Findings

Overall, high yield bond funds significantly underperform the CSFB high yield index by 1.6 percent on an annualized basis which is 0.5 percent more than the average expense ratio. Individually, funds do exhibit performance persistence and top ranked funds in one period outperform bottom ranked funds over the proceeding period by an average of 2.7 percent annually. However, except for the expense ratio, commonly used explanatory variables do not appear useful for explaining risk‐adjusted excess return differences across funds leaving 86 percent of the variation unexplained.

Research limitations/implications

This paper examines only no‐load mutual funds that have at least ten years of return data. Historical data for the explanatory variables used to explain alpha differences are limited which constrains any long‐term definitive conclusions.

Practical implications

For investors wishing to invest in this asset class, it appears that past performance does indicate future success, and investors should concentrate on the top performing funds with the lowest expense ratios.

Originality/value

This paper usefully reaffirms previous evidence on the persistence of high yield bond mutual funds, but casts doubt on the viability of using standard variables other than the expense ratio to explain risk‐adjusted returns across funds.
The manager as coach as a driver of organizational development
Authors: Ladyshewsky Richard K.
Published: June 2010

Purpose

The purpose of this paper is to explore the manager as coach (MAC) role as an organisational development strategy, in particular, aspects of the relationship between manager and employee that make it successful. The purpose of the MAC in the business context is to help employees consider how they might work and behave differently with more effective behaviours that produce better outcomes, without a reliance on the formal authority the manager possesses.

Design/methodology/approach

A qualitative case study approach was adopted in which individuals shared their experiences as MAC and/or as an employee receiving coaching from a manager in an asynchronous online discussion forum. These discussions were then qualitatively analysed.

Findings

The findings illustrate the complexity of the MAC role and why many managers fail in this role, leading to a loss of engagement and motivation of staff. Similarly, factors, which strengthen the relationship between the MAC and employee, such as trust, shared values, and benevolence lead to success in this organisational relationship.

Practical implications

Managers need to understand how to operate as a MAC to elevate organisational performance. Similarly, organisational developers need to understand what is required in training programs to develop managers into coaches if they are to employ this strategy successfully.

Originality/value

This practitioner oriented paper builds upon a case study, which explores the MAC role and integrates the findings with contemporary knowledge on performance management and coaching.
Understanding dysfunctional leader‐member exchange: antecedents and outcomes
Authors: Othman Rozhan , Fang Ee Foo , Lay Shi Ng
Published: June 2010

Purpose

The purpose of this paper is to identify a number of limitations of the theory on leader‐member exchange (LMX). This paper aims to argue that under certain conditions high quality LMX can be dysfunctional. It proceeds to identify the antecedents and outcomes of dysfunctional LMX.

Design/methodology/approach

This paper examines the theory on LMX and justice to identify the conditions that lead to dysfunctional LMX and its consequences.

Findings

A review of the extant literature indicates that favouritism by the leader and the reliance on impression management by followers can lead to dysfunctional LMX. This can then lead to negative reactions from group members and undermine work group cohesiveness.

Research limitations/implications

This paper points to new directions for research in LMX. It highlights the need to recognize that under certain conditions high quality LMX can be perceived as unfairness.

Practical implications

Managers need to recognize issues needing their attention in developing quality exchange with their subordinates. Failure to address these issues can undermine work group performance.

Originality/value

This study contributes to the debate on the role of LMX. Specifically, it attempts to add to the discussion in the emerging literature on dysfunctional LMX.
Implicit leadership theory among Malaysian managers
Authors: Subramaniam Anusuiya , Othman Rozhan , Sambasivan Murali
Published: June 2010

Purpose

This paper aims to examine implicit leadership theory (ILT) among Malaysian managers and the impact of the gap between the ILT and actual leader behavior on leader‐member exchange (LMX) quality.

Design/methodology/approach

A survey of 137 Malaysian managers working under the supervision of Malaysian and Japanese superiors in five Japanese multi‐national corporations (MNCs) in Malaysia was conducted to test the hypotheses of this study.

Findings

The results reveal that there is a distinct Malaysian ILT. It also found that there are differences in the ILT of different ethnic groups in Malaysia. Contrary to expectations, there is no significant difference in the leadership expectation gap among managers reporting to superiors from the same background compared to superiors from a different nationality and ethnic background. Duration of managers' relationship with their superior have a moderating effect on the relationship between leadership expectation gap and LMX quality.

Practical implications

The findings of this study can serve practitioners in organizational and leadership development by contributing to the awareness that ILT affects the quality of a leader's exchange within his or her followers.

Originality/value

This paper contributes to the literature by providing a first insight on ILT in the Malaysian context, particularly on the variation across the main ethnic groups in the country.
Integrating new technology in established organizations
Authors: Karlsson Christer , Taylor Margaret , Taylor Andrew
Published: June 2010

Purpose

The purpose of this paper is to identify and examine the various mechanisms that can be used to integrate new technology into existing products, and to determine some of the conditions under which specific integration mechanisms are most appropriate.

Design/methodology/approach

The paper adopted an exploratory theory‐building approach based on analysis of data from 12 case studies, each representing companies with varying levels of: technological maturity of the organization and technological advancement of their products. Informants were managers and engineers who had responsibility for, or a significant role in, the integration of software and hardware. At least three interviews were conducted in each company and all interviews were of at least two hours duration. In total, 41 interviews were conducted. The different approaches used for technology integration were examined and subsequently mapped using the twin dimensions outlined above.

Findings

Cross‐case pattern analysis indicates that for technologically mature organizations, mechanisms based on processes are most appropriate, while for less mature organizations an approach based on structural mechanisms may be more suitable. Similarly, in cases involving high levels of technology advancement in the products, integration mechanisms based on processes and culture are preferable, whereas for low technology products the mechanisms are clustered around resource‐based approaches.

Research limitations/implications

Multiple cases do not permit as much depth as the classic single case study and tend to yield “modest” rather than “grand” theoretical development. The use of scaling to convert qualitative data into quantitative data, and the identification of patterns in cross‐case analysis are both based on interpretive judgements. Future research should examine the proposed model and its constructs in different settings and using alternative research methods. There is also an opportunity to explore the relationships between the integration mechanisms and the outcomes of integration projects, and finally, it would be useful to extend the work to service settings and to integration of process technology.

Practical implications

The findings provide guidance to managers in selecting alternative approaches to managing the process of technology integration in different contexts. Examples are given of practices associated with each integration mechanism, together with some of the tensions and challenges which arise during implementation.

Originality/value

The paper provides clear guidance on the approaches that can be used for technology integration for product development. It classifies these according to the level of maturity and experience in the organization and the level of advancement of the product offered by the technology.
Applying of genetic algorithm for optimizing methane combustion reactions
Authors: Labbaf Khaniki Vahid , Seraj Mehdizadeh Nasser
Published: June 2010

Purpose

The aim of this paper is to find the optimal values of the reaction rates coefficients for the combustion of a methane/air mixture for a given reduced reaction mechanism which has a high appropriateness with full reaction mechanism.

Design/methodology/approach

A multi‐objective genetic algorithm (GA) was used to determine new reaction rate parameters (A's, β's, and Ea's in the non‐Arrhenius expressions). The employed multi‐objective structure of the GA allows for the incorporation of perfectly stirred reactor (PSR), laminar premixed flames, opposed flow diffusion flames, and homogeneous charge compression ignition (HCCI) engine data in the inversion process, thus enabling a greater confidence in the predictive capabilities of the reaction mechanisms obtained.

Findings

The results of this study demonstrate that the GA inversion process promises the ability to assess combustion behaviour for methane, where the reaction rate coefficients are not known. Moreover it is shown that GA can consider a confident method to be applied, straightforwardly, to the combustion chambers, in which complex reactions are occurred.

Originality/value

In this paper, GA is used in more complicated combustion models with fewer assumptions. Another consequence of this study is less CPU time in converging to final solutions.