bluuebunny/crossref_metadata_2025 huggingface dataset:
Gyrokinetic simulations of ion temperature gradient modes in the reversed field pinch
Authors: Predebon I. , Angioni C. , Guo S. C.
Published: January 2010

Linear gyrokinetic calculations are applied to the reversed field pinch configuration to investigate the occurrence of ion temperature gradient instabilities. The analysis shows this type of instability to be only marginally responsible for particle and energy transport. The required gradients could be reached only in correspondence to the temperature slopes arising at the boundary of the helical structure in the quasisingle helicity states. The dependence of the instability threshold on the relevant macroscopic quantities is considered. A discussion on the main differences in the driving mechanisms existing between the reversed field pinch and the tokamak configuration is addressed.
A volume-based hydrodynamic approach to sound wave propagation in a monatomic gas
Authors: Dadzie S. Kokou , Reese Jason M.
Published: January 2010

We investigate sound wave propagation in a monatomic gas using a volume-based hydrodynamic model. In Dadzie et al. [Physica A 387, 6079 (2008)], a microscopic volume-based kinetic approach was proposed by analyzing molecular spatial distributions; this led to a set of hydrodynamic equations incorporating a mass-density diffusion component. Here we find that these new mass-density diffusive flux and volume terms mean that our hydrodynamic model, uniquely, reproduces sound wave phase speed and damping measurements with excellent agreement over the full range of Knudsen number. In the high Knudsen number (high frequency) regime, our volume-based model predictions agree with the plane standing waves observed in the experiments, which existing kinetic and continuum models have great difficulty in capturing. In that regime, our results indicate that the “sound waves” presumed in the experiments may be better thought of as “mass-density waves,” rather than pressure waves.
The reflection of an electromagnetic wave from the self-produced plasma
Authors: Mirzaie M. , Shokri B. , Rukhadze A. A.
Published: January 2010

The dynamic behavior of a high power microwave beam propagating through a gaseous medium, which is ionized in the wave field is investigated. By solving the wave equation, the reflection index of the produced plasma is obtained. It is shown that the cut off condition is different from that of the steady state approximation. The reflection index is less than unity when the plasma density reaches the critical value estimated in the steady state approximation. So, the wave can still propagate through the plasma. By comparing the reflection indexes in the presence and absence of the time delay of the ionization process at different points of the medium, it is shown that it becomes unity much later in the first case. Therefore, the wave propagation takes much more time and consequently the medium is ionized much more.
Electron beam current in high power cylindrical diode
Authors: Roy Amitava , Menon R. , Mitra S. , Sharma Vishnu , Singh S. K. , Nagesh K. V. , Chakravarthy D. P.
Published: January 2010

Intense electron beam generation studies were carried out in high power cylindrical diode to investigate the effect of the accelerating gap and diode voltage on the electron beam current. The diode voltage has been varied from 130 to 356 kV, whereas the current density has been varied from 87 to 391 A/cm2 with 100 ns pulse duration. The experimentally obtained electron beam current in the cylindrical diode has been compared with the Langmuir–Blodgett law. It was found that the diode current can be explained by a model of anode and cathode plasma expanding toward each other. However, the diode voltage and current do not follow the bipolar space-charge limited flow model. It was also found that initially only a part of the cathode take part in the emission process. The plasma expands at 4.2 cm/μs for 1.7 cm anode-cathode gap and the plasma velocity decreases for smaller gaps. The electrode plasma expansion velocity of the cylindrical diode is much smaller as compared with the planar diode for the same accelerating gap and diode voltage. Therefore, much higher voltage can be obtained for the cylindrical diodes as compared with the planar diodes for the same accelerating gap.
Kadison–Singer algebras: Hyperfinite case
Authors: Ge Liming , Yuan Wei
Published: January 2010

A new class of operator algebras, Kadison–Singer algebras (KS-algebras), is introduced. These highly noncommutative, non-self-adjoint algebras generalize triangular matrix algebras. They are determined by certain minimally generating lattices of projections in the von Neumann algebras corresponding to the commutant of the diagonals of the KS-algebras. A new invariant for the lattices is introduced to classify these algebras.
Solar-powered drip irrigation enhances food security in the Sudano–Sahel
Authors: Burney Jennifer , Woltering Lennart , Burke Marshall , Naylor Rosamond , Pasternak Dov
Published: January 2010

Meeting the food needs of Africa’s growing population over the next half-century will require technologies that significantly improve rural livelihoods at minimal environmental cost. These technologies will likely be distinct from those of the Green Revolution, which had relatively little impact in sub-Saharan Africa; consequently, few such interventions have been rigorously evaluated. This paper analyzes solar-powered drip irrigation as a strategy for enhancing food security in the rural Sudano–Sahel region of West Africa. Using a matched-pair comparison of villages in northern Benin (two treatment villages, two comparison villages), and household survey and field-level data through the first year of harvest in those villages, we find that solar-powered drip irrigation significantly augments both household income and nutritional intake, particularly during the dry season, and is cost effective compared to alternative technologies.
Identical phosphatase mechanisms achieved through distinct modes of binding phosphoprotein substrate
Authors: Pazy Y. , Motaleb M. A. , Guarnieri M. T. , Charon N. W. , Zhao R. , Silversmith R. E.
Published: January 2010

Two-component signal transduction systems are widespread in prokaryotes and control numerous cellular processes. Extensive investigation of sensor kinase and response regulator proteins from many two-component systems has established conserved sequence, structural, and mechanistic features within each family. In contrast, the phosphatases which catalyze hydrolysis of the response regulator phosphoryl group to terminate signal transduction are poorly understood. Here we present structural and functional characterization of a representative of the CheC/CheX/FliY phosphatase family. The X-ray crystal structure of
Borrelia burgdorferi
CheX complexed with its CheY3 substrate and the phosphoryl analogue

reveals a binding orientation between a response regulator and an auxiliary protein different from that shared by every previously characterized example. The surface of CheY3 containing the phosphoryl group interacts directly with a long helix of CheX which bears the conserved (E - X
2
 - N) motif. Conserved CheX residues Glu96 and Asn99, separated by a single helical turn, insert into the CheY3 active site. Structural and functional data indicate that CheX Asn99 and CheY3 Thr81 orient a water molecule for hydrolytic attack. The catalytic residues of the CheX·CheY3 complex are virtually superimposable on those of the
Escherichia coli
CheZ phosphatase complexed with CheY, even though the active site helices of CheX and CheZ are oriented nearly perpendicular to one other. Thus, evolution has found two structural solutions to achieve the same catalytic mechanism through different helical spacing and side chain lengths of the conserved acid/amide residues in CheX and CheZ.
Modes of knowledge acquisition and retrieval in artificial grammar learning
Authors: Poznanski Yael , Tzelgov Joseph
Published: January 2010

The aim of this study was to conceptualize artificial grammar learning (AGL) in terms of two orthogonal dimensions—the mode of knowledge acquisition and the mode of knowledge retrieval—as was done by Perlman and Tzelgov (2006) for sequence learning. Experiment 1 was carried out to validate our experimental task; Experiments 2–4 tested, respectively, performance in the intentional, incidental, and automatic retrieval modes, for each of the three modes of acquisition. Furthermore, signal detection theory (SDT) was used as an analytic tool, consistent with our assumption that the processing of legality-relevant information involves decisions along a continuous dimension of fluency. The results presented support the analysis of AGL in terms of the proposed dimensions. They also indicate that knowledge acquired during training may include many aspects of the presented stimuli (whole strings, relations among elements, etc.). The contribution of the various components to performance depends on both the specific instruction in the acquisition phase and the requirements of the retrieval task.
Equivariant Littlewood-Richardson skew tableaux
Authors: Kreiman Victor
Published: January 2010

We give a positive equivariant Littlewood-Richardson rule also discovered independently by Molev. Our proof generalizes a proof by Stembridge of the classical Littlewood-Richardson rule. We describe a weight-preserving bijection between our indexing tableaux and trapezoid puzzles which restricts to a bijection between positive indexing tableaux and Knutson-Tao puzzles.
Divergence in lattices in semisimple Lie groups and graphs of groups
Authors: Druţu Cornelia , Mozes Shahar , Sapir Mark
Published: January 2010

Divergence functions of a metric space estimate the length of a path connecting two points

A
A

,

B
B

at distance

≤
n

\le n

avoiding a large enough ball around a third point

C
C

. We characterize groups with non-linear divergence functions as groups having cut-points in their asymptotic cones. That property is weaker than the property of having Morse (rank 1) quasi-geodesics. Using our characterization of Morse quasi-geodesics, we give a new proof of the theorem of Farb-Kaimanovich-Masur that states that mapping class groups cannot contain copies of irreducible lattices in semi-simple Lie groups of higher ranks. It also gives a generalization of the result of Birman-Lubotzky-McCarthy about solvable subgroups of mapping class groups not covered by the Tits alternative of Ivanov and McCarthy.

We show that any group acting acylindrically on a simplicial tree or a locally compact hyperbolic graph always has “many” periodic Morse quasi-geodesics (i.e. Morse elements), so its divergence functions are never linear. We also show that the same result holds in many cases when the hyperbolic graph satisfies Bowditch’s properties that are weaker than local compactness. This gives a new proof of Behrstock’s result that every pseudo-Anosov element in a mapping class group is Morse.

On the other hand, we conjecture that lattices in semi-simple Lie groups of higher rank always have linear divergence. We prove it in the case when the

Q

\mathbb {Q}

-rank is 1 and when the lattice is

SL
n

⁡
(

O

S

)

\operatorname {SL}_n(\mathcal {O}_{\mathcal {S}})

where

n
≥
3

n\ge 3

,

S
S

is a finite set of valuations of a number field

K
K

including all infinite valuations, and

O

S

\mathcal {O}_{\mathcal {S}}

is the corresponding ring of

S
S

-integers.
The cut-off covering spectrum
Authors: Sormani Christina , Wei Guofang
Published: January 2010

We introduce the

R
R

cut-off covering spectrum and the cut-off covering spectrum of a metric space or a Riemannian manifold. The spectra measure the sizes of localized holes in the space and are defined using covering spaces called

δ
\delta

covers and

R
R

cut-off

δ
\delta

covers. They are investigated using

δ
\delta

homotopies which are homotopies via grids whose squares are mapped into balls of radius

δ
\delta

.

On locally compact spaces, we prove that these new spectra are subsets of the closure of the length spectrum. We prove the

R
R

cut-off covering spectrum is almost continuous with respect to the pointed Gromov-Hausdorff convergence of spaces and that the cut-off covering spectrum is also relatively well behaved. This is not true of the covering spectrum defined in our earlier work, which was shown to be well behaved on compact spaces. We close by analyzing these spectra on Riemannian manifolds with lower bounds on their sectional and Ricci curvature and their limit spaces.
Complexity and anisotropy in host morphology make populations less susceptible to epidemic outbreaks
Authors: Pérez-Reche Francisco J. , Taraskin Sergei N. , Costa Luciano da F. , Neri Franco M. , Gilligan Christopher A.
Published: January 2010

One of the challenges in epidemiology is to account for the complex morphological structure of hosts such as plant roots, crop fields, farms, cells, animal habitats and social networks, when the transmission of infection occurs between contiguous hosts. Morphological complexity brings an inherent heterogeneity in populations and affects the dynamics of pathogen spread in such systems. We have analysed the influence of realistically complex host morphology on the threshold for invasion and epidemic outbreak in an SIR (susceptible–infected–recovered) epidemiological model. We show that disorder expressed in the host morphology and anisotropy reduces the probability of epidemic outbreak and thus makes the system more resistant to epidemic outbreaks. We obtain general analytical estimates for minimally safe bounds for an invasion threshold and then illustrate their validity by considering an example of host data for branching hosts (salamander retinal ganglion cells). Several spatial arrangements of hosts with different degrees of heterogeneity have been considered in order to separately analyse the role of shape complexity and anisotropy in the host population. The estimates for invasion threshold are linked to morphological characteristics of the hosts that can be used for determining the threshold for invasion in practical applications.
ZBP1 recognition of β-actin zipcode induces RNA looping
Authors: Chao Jeffrey A. , Patskovsky Yury , Patel Vivek , Levy Matthew , Almo Steven C. , Singer Robert H.
Published: January 2010

ZBP1 (zipcode-binding protein 1) was originally discovered as a trans-acting factor for the “zipcode” in the 3′ untranslated region (UTR) of the β-actin mRNA that is important for its localization and translational regulation. Subsequently, ZBP1 has been found to be a multifunctional regulator of RNA metabolism that controls aspects of localization, stability, and translation for many mRNAs. To reveal how ZBP1 recognizes its RNA targets, we biochemically characterized the interaction between ZBP1 and the β-actin zipcode. The third and fourth KH (hnRNP K homology) domains of ZBP1 specifically recognize a bipartite RNA element located within the first 28 nucleotides of the zipcode. The spacing between the RNA sequences is consistent with the structure of IMP1 KH34, the human ortholog of ZBP1, that we solved by X-ray crystallography. The tandem KH domains are arranged in an intramolecular anti-parallel pseudodimer conformation with the canonical RNA-binding surfaces at opposite ends of the molecule. This orientation of the KH domains requires that the RNA backbone must undergo an ∼180° change in direction in order for both KH domains to contact the RNA simultaneously. The RNA looping induced by ZBP1 binding provides a mechanism for specific recognition and may facilitate the assembly of post-transcriptional regulatory complexes by remodeling the bound transcript.
Silent information regulator 3: the Goldilocks of the silencing complex
Authors: Norris Anne , Boeke Jef D.
Published: January 2010

A recent explosion of work surrounds the interactions between Sir3p (Silent Information Regulator 3) and chromatin. We review here the Sir3p functions related to its role in silencing in Saccharomyces cerevisiae. This unusual protein, which is absolutely required for silencing, is distantly related to the highly conserved replication initiator Orc1p, but is itself phylogenetically limited to “post-genome-duplicated” budding yeasts. Several recent studies revise earlier models for Sir3p action. Specifically, the N-terminal bromo-adjacent homology (BAH) domain plays a now well-defined role in silencing, and a picture is emerging in which both termini of Sir3p bind two locations on the nucleosome: (1) the loss of ribosomal DNA silencing (LRS) surface in the nucleosome core, and (2) the N-terminal histone tails for effective silencing at telomeres. We relate Sir3p structure and function, and summarize recent molecular studies of Sir3p/chromatin binding, Sir3p/Dot1p competition, and the possible role of O-Acetyl ADP ribose (O-AADPR) in Sir3p/chromatin binding. We emphasize recent genetic data that provide important new insights and settle controversies created by in vitro work. Finally, we synthesize these ideas to revise the model for how Sir3p mediates silent chromatin formation in yeast, in part through its affinity for the LRS region of the nucleosome, which must be “just right.”
Error-free replicative bypass of (6–4) photoproducts by DNA polymerase ζ in mouse and human cells
Authors: Yoon Jung-Hoon , Prakash Louise , Prakash Satya
Published: January 2010

The ultraviolet (UV)-induced (6–4) pyrimidine–pyrimidone photoproduct [(6–4) PP] confers a large structural distortion in DNA. Here we examine in human cells the roles of translesion synthesis (TLS) DNA polymerases (Pols) in promoting replication through a (6–4) TT photoproduct carried on a duplex plasmid where bidirectional replication initiates from an origin of replication. We show that TLS contributes to a large fraction of lesion bypass and that it is mostly error-free. We find that, whereas Pol η and Pol ι provide alternate pathways for mutagenic TLS, surprisingly, Pol ζ functions independently of these Pols and in a predominantly error-free manner. We verify and extend these observations in mouse cells and conclude that, in human cells, TLS during replication can be markedly error-free even opposite a highly distorting DNA lesion.
Differential regulation of p53 target genes: it's (core promoter) elementary: Figure 1.
Authors: Gomes Nathan P. , Espinosa Joaquín M.
Published: January 2010

p53 is a pleiotropic transcription factor driving a flexible transcriptional program that mediates disparate cellular responses to stress, including cell cycle arrest and apoptosis. The mechanisms by which p53 differentially regulates its diverse target genes remain poorly understood. In this issue of Genes & Development, Morachis and colleagues (pp. 135–147) demonstrate the critical role of core promoter elements at p53 target loci, in that they dictate differential RNA polymerase II recruitment and activity in a p53-autonomous fashion.
Marron farming in Western Australia: scope and constraints
Authors: Duarte Alonso Abel
Published: January 2010

Purpose

Marron farming in Western Australia has existed for decades. However, to what extent do marron growers see potential in this industry in ways that include expanding into hospitality and tourism? The purpose of this paper is to examine this dimension from a group of 26 marron growers.

Design/methodology/approach

The limited knowledge on marron farming from an academic, industry, as well as from operators' perspective is a critical factor in choosing a qualitative approach in this paper in the form of telephone and face‐to‐face interviews.

Findings

Overall, there is an agreement among respondents about the significant commercial potential of marron farming. However, the dilemma of satisfying increasing demand for marron is acknowledged, as well as resulting problems, for instance, in the form of greed and lack of unity among some growers.

Research limitations/implications

While the low number of respondents may not be sufficient to make generalisations of the marron farming industry, this paper proposes an overview into an unexplored industry, and provides useful insights into a niche market.

Practical implications

Increased demand for marron in both national and international markets presents opportunities for local operators and the future of marron farming. At the same time, a balance must be maintained in order to preserve natural resources and the industry's sustainability.

Originality/value

Despite its demand and potential, to date very limited research has been conducted on marron farming, particularly studying the links between marron, hospitality and tourism, as well as marron growers' points of views on this industry. This exploratory paper contributes to narrowing the existing knowledge gap on these dimensions.
Inpatriates' adjustment to home country headquarters: a social/cultural conundrum
Authors: Williams Wallace A. , Moeller Miriam , Harvey Michael
Published: January 2010

Purpose

The purpose of this paper is to examine Trompenaars' cultural dimensions using reference point theory to propose the adjustment difficulties that inpatriates will experience when entering the home market/global headquarters organization culture.

Design/methodology/approach

Specifically, it examines means by which the organization may maintain the inpatriate's perspective while at the same time provide training/development to assist in integrating the inpatriate manager into the global management team.

Findings

The paper proposes that the inpatriate's origin plays a significant part in determining the difficulty of adjusting to the headquarter culture as well as to the general culture of the new home country. The need for reference points (internal, external and time) becomes vital in that each allows for a better understanding of the adjustment process.

Research limitations/implications

With regard to the two variables (macro and organizational culture) examined, it should be noted that cultural distance is not of sole importance in the adjustment process of the inpatriate. Additional factors to consider include job type, previous experience in home country of the organization, local support groups and other socialization tactics.

Practical implications

To facilitate the cross‐cultural adjustment process, active attempts by human resource management staff must be undertaken to help ensure adjustment. Successful adjustment would allow inpatriates to provide valuable insight and contribute to the global organizations' success.

Originality/value

This paper adds value by providing a theoretically based framework for the adjustment of inpatriates that can be tested and modified by future researchers. Furthermore, it provides a guide to inpatriate adjustment so that their maximum value to the organization can be achieved.
Modeling the non‐linear behaviour of option price deviations from the Black Scholes model
Authors: Gregoriou Andros
Published: January 2010

Purpose

The purpose of this paper is to test for and model non‐linearities in option price deviations from the Black Scholes (BS) model in FTSE 100 index options over the time period 1997‐2006.

Design/methodology/approach

The economic specification and estimation methodology is outlined, the data are discussed, and the empirical results are analysed.

Findings

The tests reject the linearity hypothesis and the paper shows that the exponential smooth transition autoregressive model is capable of capturing the non‐linear behaviour of option price misalignments. The paper finds that even though FTSE 100 index options are heavily traded, transaction costs prevent rapid adjustments of option prices from their “optimal” value.

Originality/value

The paper presents new empirical evidence, which explicitly allows for the possibility that option price misalignments from the BS price can be characterised by a non‐linear mean reverting process.
The enduring significance of the thought of Karl Marx
Authors: Jeannot Tom
Published: January 2010

Purpose

The purpose of this paper is to assess Marx's enduring significance in the center of his thought, the first volume of Capital. In Capital and related writings, Marx systematically works out his theory of value. Although Marx's value theory has been widely thought to be internally inconsistent, the “myth of inconsistency” in reclaiming Marx's “Capital” has been recently refuted by Kliman.

Design/methodology/approach

Based on Kliman's refutation, a logically coherent interpretation of Marx's theory is on hand. The paper therefore aims to bring out the philosophical character of Marx's critique of political economy, to which the terms and relations of value theory are essential. It is rooted in the abiding humanism he first discovered through his critical appropriation and transformation of Hegelian philosophy.

Findings

Following Raya Dunayevskaya in Marxism and Freedom, this paper interprets Marx to have founded a new critical science of society “that was at the same time a philosophy of history.” Hence Marx's use of ontological categories in Capital (“substance,” “essence,” “appearance”) is fully methodologically self‐conscious and deliberate. Categories derived from Hegel's Science of Logic (as Lenin rightly grasped) explain the “bewitched and distorted world” of capitalist social relations.

Originality/value

This paper shows that, thinking historically, Marx works out the “notion” of capital from the standpoint of its negation. As if seen through a camera obscura, capital is the domination of alienated, past, objectified, abstract, and dead labor over living labor power. In conclusion, emphasis is placed on the subjective as well as the objective condition necessary to the revolutionary transcendence of the law of value.
Putnam and radical socio‐economic theory
Authors: Manning Paul
Published: January 2010

Purpose

The purpose of this paper is to review the social capital treatment of Robert Putnam, the most influential conceptual theorist. The paper will detail how Putnam's treatment of social capital has evolved, examine the arguments of his critics and will also critique his socio‐economic analysis.

Design/methodology/approach

The approach taken is a literature review that investigates Putnam's social capital understanding and considers the reasons why this conceptual treatment “touched a nerve” and proved so influential and adaptable.

Findings

Putnam's social capital treatment belongs to a socio‐economic communitarian tradition that can be traced to de‐Tocqueville, which offers an alternative to both mainstream free market ideology and to leftwing socio‐economics.

Originality/value

The originality of this paper is to identify Putnam as a radical in a methodological sense, reinvigorating a Burkean, consensual interpretation of socio‐economics. The value of this paper is to offer a critique of Putnam's interpretation of social capital.
Relationship governance and learning in partnerships
Authors: Kohtamäki Marko
Published: January 2010

Purpose

Relationship learning is a topic of considerable importance for industrial networks, yet a lack of empirical research on the impact of relationship governance structures on relationship learning remains. The purpose of this paper is to analyze the impact of relationship governance structures on learning in partnerships.

Design/methodology/approach

This paper contributes to the closure of the research gap by examining sample data drawn from 42 interviews on the subject of 199 customer‐supplier relationships within the Finnish metal and electronics industries. As a method, the paper applies cluster analysis and analysis of variance mean‐comparison.

Findings

The results of this paper show that balanced hybrid governance structures explain learning in partnerships, which suggests that certain combinations of relationship governance mechanisms (price, hierarchical, and social mechanism) produce the best learning outcomes in partnerships. Results suggest that managers should use hybrid relationship governance structures when governing their supplier partnerships.

Research limitations/implications

The paper has some limitations such as limited sample size, cross‐sectional data, and difficulties due to measuring social phenomenon such as learning. Owing to the interview method being applied, research is bound to apply a sample data drawn from companies that operate in the west coast in Finland. These limitations need to be considered when applying the results.

Practical implications

The results encourage managers to use different governance mechanisms simultaneously when managing their company's supply chain partnerships. The result emphasizes the role of active relationship management.

Originality/value

The paper is one of the first to empirically show that relationship learning is best facilitated by using various relationship governance mechanisms simultaneously. Trust needs to be complemented by hierarchical and possibly by price mechanism.
The role of Internet in the development of future software projects
Authors: Martínez‐Torres M.R. , Toral S.L. , Barrero F. , Cortés F.
Published: January 2010

Purpose

The Internet has evolved, prompted in part by new Web 2.0 technologies, to become a more widespread platform for interaction, communication, and activism. Virtual communities, or groups of people informally bound together by shared expertise, synthesise this Internet evolution and the Web 2.0 technology. Users increasingly want to engage online with one another and with organisations of all kinds. These novel Internet‐based technologies dominate the new business models of the digital economy giving companies radical new ways to harvest the talents of innovators working outside corporate boundaries. One of the most illustrative examples of this new trend is the Open Source Software (OSS) projects development. This paper aims to analyse the structure and topology of the virtual community supporting one of the most successfully OSS projects, Linux. The objective is to provide conclusions for being successful in the development of future virtual communities. As companies learn to manage these virtual communities, they will develop smarter and faster ways to create value through them.

Design/methodology/approach

The interactions of the virtual community members of an ARM‐embedded Linux project website is analysed through social network analysis techniques. The participants' activity is studied and some conclusions about the participation features are obtained using the Gini coefficient. In particular, a participation inequality behaviour or a concentration on a small number of developers is clearly observed.

Findings

The paper deals with the guidelines that virtual communities should follow to be successful. Results about the structure of a successful virtual community and its time evolution are provided to determine the mentioned guidelines.

Research limitations/implications

The research is limited to a particular virtual community engaged with the development of the ARM‐embedded Linux OSS. Other successful virtual communities can be analysed, and the conclusions could be compared. Anyway, the proposed analysis methodology can be extended to other virtual communities.

Originality/value

The paper fulfils the development and features of Internet virtual communities to be successful. Results have important implications over the development of new software business models based on virtual communities and open source software. Contributions about the best organisation of virtual communities leading to a successful development of the underlying project are presented.
Sustainable information systems: a knowledge perspective
Authors: Maruster Laura , Faber Niels R. , Peters Kristian
Published: January 2010

Purpose

The purpose of this paper is to propose a re‐orientation of the way the concept of sustainability is dealt with in relation to information systems, positioning human behaviour and the processing of knowledge at the centre of the concept.

Design/methodology/approach

The concept of sustainability of knowledge (SoK), which refers to processes that govern knowledge, is employed to define sustainable information systems (SIS). Following this definition, knowledge aspects are employed to tackle the notion of sustainability. The sustainability approach presented in this paper is then translated into requirements needed for designing a SIS.

Findings

Three knowledge aspects are found to be relevant for the design of SIS: adaptability, offloading and knowledge evaluation. The service oriented‐based architecture (SOA) seems to be appropriate to support the proposed approach.

Research limitations/implications

The conceptual approach proposed need to be evaluated by case studies to be performed in different organizations.

Originality/value

A knowledge based perspective is proposed to re‐orient the notion of sustainability. Moreover, an SOA architecture is used to design a system based on the proposed approach.
The role of bonding duration in wire bond formation: a study of footprints of thermosonic gold wire on aluminium pad
Authors: Xu Hui , Liu Changqing , Silberschmidt Vadim V. , Chen Zhong , Wei Jun
Published: January 2010

Purpose

Optimization of the process parameters remains a challenging task in thermosonic wire bonding due to relatively poor understanding of the bonding mechanism. The purpose of this paper is to understand initial bond formation in thermosonic gold wire bonding on aluminium metallization pads and the effect of bonding time on the initiation of bonding.

Design/methodology/approach

A gold wire (20 μm diameter/99.99 per cent wt%) was bonded to aluminium metallization pads (1 μm thick) on a silicon chip using a commercial ball/wedge automatic bonder. Bonding parameters were selected specifically to produce underdeveloped ball bonds so that ball lift‐off occurred during looping process. The lift‐off footprints on the aluminium metallization pads and their evolution were carried out using optical microscopy and scanning electron microscopy. A model is proposed to elaborate the effect of bonding time on initiation of bonding.

Findings

The obtained results showed that metallurgical bonding initiated at the peripheral areas of the contact area situated along the direction of ultrasonic vibration. Those areas extended inwards with bonding time, eventually covering the entire contact area.

Originality/value

This paper describes how bond initiation and its evolution in thermosonic gold wire bonding on aluminium metallization is ascertained by observing lift‐off footprints. The understanding of bonding mechanism benefits the optimization of process parameters and improvement of bondability in thermosonic wire bonding.
Aluminium‐silicon alloy and its composites reinforces by silicon carbide particles
Authors: Tahat Montasser S.
Published: January 2010

Purpose

The purpose of this paper is to investigate the effect of SiC addition up to 60 percent SiC on the mechanical properties and thermal expansion of Al‐7vol.% Si/SiC composites.

Design/methodology/approach

Composite specimens containing 7, 15, 30, 45 and 60 vol.% SiCp are fabricated by pressureless infiltration technique. The obtained metal‐matrix composites (MMCs) then are characterized for density, porosity, microhardness, ductility, and coefficients of thermal expansion (CTE).

Findings

The results show that the composite specimens have very low‐porosity volumes. Moreover, it is found that silicon carbide particles are distributed uniformly in the matrix. Both porosity and mean linear CTE of the composites decreases with silicon carbide volume fraction. However, higher amount of SiCp reinforcement content tends to increase density, microhardness and improve ductility.

Originality/value

The processing employed in this paper would enable realization of electronic packages made out of Al‐Si/SiCp MMCs.
Development of 2.4 and 3.5 GHz 0.15 μm GaAs PHEMT medium‐power amplifier employing core‐based design approach
Authors: Rasmi Amiza , Marzuki Arjuna , Nizam Osman Mohd , Ismat Abdul Rahim Ahmad , Razman Yahya Mohamed , Fatah Awang Mat Abdul
Published: January 2010

Purpose

The purpose of this paper is to discuss medium‐power amplifier (MPA) design using parasitic‐aware core‐based approach.

Design/methodology/approach

This paper discusses a core‐based design approach, which can also deliver multi‐band radio frequency integrated circuit.

Findings

A fabricated 3.5 GHz MPA achieved a P1dB of 16.81 dBm, power‐added efficiency (PAE) of 16.74 percent and gain of 6.81 dB at the 10 dBm of input power under a low‐power supply of 3 V. The maximum current, Imaxis 80.7 mA and the power consumption of the device is 242.10 mW. A fabricated 2.4 GHz MPA achieved a P1dB of 14.83 dBm, PAE of 11.73 percent and gain of 9.83 dB at the 5.0 dBm of input power under a low‐power supply of 3.0 V. The maximum current, Imaxis 84.4 mA and the power consumption for this device is 253.20 mW.

Originality/value

This paper shows the merits of the parasitic‐aware design methods used in designing the core circuit.
Design of SIPC‐based complementary LC‐QVCO in 0.18‐μm CMOS technology for WiMAX application
Authors: Ramiah Harikrishnan , Zainal Azni Zulkifli Tun , Sapiee Noramalia
Published: January 2010

Purpose

The purpose of this paper is to design and realize a low‐phase noise, high‐output power, and high‐tuning range, fully integrated source injection parallel coupled (SIPC)‐based inductor‐capacitor (LC)‐quadrature voltage controlled oscillator (QVCO) covering WiMAX frequency range in 0.18‐μm deep submicron CMOS technology.

Design/methodology/approach

A pMOS based‐SIPC LC‐QVCO topology is realized with the center frequency of 2.58 GHz. On chip spiral inductor is integrated with substantial quality factor, Q coupled with underlying pattern ground shield (PGS) shielding. An enhanced tuning range is achieved by integrating the diode connected MOS‐based varactors. The CMOS‐based autonomous SIPC LC‐QVCO circuit was characterized for its output phase noise, tuning range and power spectrum response via wafer probing, utilizing a signal source analyzer (Agilent E5052 A).

Findings

A quadrature oscillator catering to the needs of local oscillator (LO) generation covering the frequency range of WiMAX is realized. The parallel coupled architecture adapts direct source coupling, bypassing the LC resonator tank and relaxes the close in phase noise up‐conversion. The design consumes 2.19 mm2of active chip area and measures a phase noise of −114.34 dBc/Hz at 1 MHz of offset frequency with 2.67 GHz of output frequency at 0.9 V of input tuning voltage. The corresponding output power measures to be −10.1 dBm, well suited for mixer hard switching. The design is realized in one poly, six metal 0.18‐μm standard CMOS technology.

Research limitations/implications

Owing to convergence discrepancy in the analysis, a diode‐connected MOS varactor is adapted in contrary to the accumulation mode MOS varactors with superior tuning range.

Practical implications

The designed SIPC LC‐QVCO is of need in the generation of low‐phase noise, highly matched quadrature LO generation covering the WiMAX frequency range. The adapted parallel coupling also relaxes the voltage headroom limitation.

Originality/value

This paper shows how a fully integrated CMOS‐based SIPC LC‐QVCO architecture is adapted with low‐output phase noise and low voltage headroom consumption covering the WiMAX frequency range.
Outsourcing of NPD activities: a best practice approach
Authors: Rundquist Jonas , Halila Fawzi
Published: January 2010

Purpose

The purpose of this paper is to improve the understanding of outsourcing new product development (NPD), and specifically of factors affecting the outsourcing decisions, by exploring the practices of the most innovative firms.

Design/methodology/approach

The paper draws on an internet‐based survey sent in winter 2008 to 494 medium‐sized firms in four industries which achieved a 77.3 percent response rate. The sample is split into the best firms and the rest, and a best practice analysis is performed with correlation analysis.

Findings

The best firms focus on knowledge issues to a higher extent, while cost and geographical proximity are more important for the rest firms. The best firms prioritize knowledge integration and development of knowledge about the outsourcing process higher.

Research limitations/implications

The sample is taken from medium‐sized Swedish manufacturing firms. Future samples need to be expanded to further generalize the conclusions. Results show that further research combining resource and cost perspectives is needed.

Practical implications

Managers are recommended to not only find access to needed knowledge, but also give time to integration on a personal level, as this protects knowledge and lowers costs in the long‐run.

Originality/value

Studies of outsourcing NPD are few and, to the authors’ knowledge, no quantitative studies on the topic have been made.
Revisiting the case of float glass
Authors: Uusitalo Olavi , Mikkola Toni
Published: January 2010

Purpose

The purpose of this paper is twofold. First and most importantly, the paper aims to explain how Pilkington is able to revolutionize the flat glass industry. The modified design envelope model is applied to demonstrate the technological competence and especially strategic thinking concerning to understanding of the markets and positioning the product. Second, the paper demonstrates the entrepreneurship within a large‐scale manufacturing firm.

Design/methodology/approach

The paper applies a longitudinal, historical, and contextual approach. The paper uses multiple case study method and multiple data sources. This is done because creation of an innovation does not take place in vacuum, it is context bound.

Findings

The float glass fulfills the requirements of two industries: the plate and sheet glasses. Within both industries, short‐sighted competitors concentrate on technologies applicable only in other industry. Pilkington positions the float glass first clearly in the plate glass industry and after further development introduces the technology to sheet glass industry as a total surprise. Based on the case, the paper argues that positioning should be part of the corporate strategy.

Practical implications

In addition to complex systematic technologies, the example shows that the design envelope model is applicable also for simple non‐assembled products like flat glass. The model is useful for companies to build scenarios for responses if new unexpected innovations will be introduced in its own or related industries.

Originality/value

This paper offers a novel insight to the old but still viable case of dominant design. In addition, the thorough case description allows reader to go deeply into a classic example of process innovation.
The licensing and launch of high‐speed mobile telecommunications networks in Europe
Authors: Curwen Peter
Published: January 2010

Purpose

The purpose of this paper is to investigate the licensing and launch of high‐speed mobile telecommunications networks in Europe.

Design/methodology/approach

The research is based upon data collection from multiple sources, triple cross‐checked, on licensing and launch dates and other relevant information.

Findings

A series of tables are presented covering a variety of relevant data such as licence and launch dates, megahertz awarded, number of licensees and methods of awards.

Research limitations/implications

Despite triple‐checking, some uncertainties remain about the precise numbers in a limited number of cases.

Originality/value

No one has ever conducted a detailed investigation of this kind before.
Whatever happened to human resource management performance?
Authors: Prowse Peter , Prowse Julie
Published: January 2010

Purpose

The purpose of this paper is to critically explore the evidence that human resource management (HRM) could contribute to the improvement of organizational and individual performance. It aims to examine the historical development of HRM and its emergence as a distinct management discipline. The evidence indicates that HRM is the product of several different traditions that range from a concern with employee welfare to the development of workplace relationships. The paper critically re‐evaluates what human performance is and assesses its contribution to organizational effectiveness. What is particularly important is the lack of empirical literature on the contribution of HRM and business performance. This paper will call for the re‐evaluation of more contemporary criteria of how people contribute to organizational performance in private, public and the emerging non‐profit making sectors.

Design/methodology/approach

The methodology adopted in this research uses critical literature on the contribution of human resource management performance.

Findings

The main finding of this research is the understanding of the problems of research design in measuring the contribution of HRM to develop performance in organizations.

Research limitations/implications

The research presented in this paper needs to review and standardize comparative research design to confirm the performance of HRM in organizations. It compares the alternative perspectives of measuring performance in financial criteria.

Originality/value

This paper reviews the research between key authors for exploring the correlation between HRM and organizational performance for future research and examines the influence of human resource professional bodies.
The craft of project shaping
Authors: Smith Charles , Winter Mark
Published: January 2010

Purpose

This paper aims to look closely at the actuality of project formation to investigate the performance of project shaping – those acts performed by individuals to make that form of “sense” that constitutes a new project, and to propose a framework for mapping the skills of those individuals who are directly involved in shaping projects.

Design/methodology/approach

The paper uses a sensemaking approach from illustrative narratives in order to propose a model of how a project outcome is shaped. The analysis is based on thinking that emerged from the Rethinking Project Management Network and other academic communities.

Findings

Significant factors in project formation are: the timing of the conversion of work into controlled project form (the control model of projects), the role of factional interests and power structures (tribal power), the alignment of project scope with a need for transformation (transformation and value), the fast production of tangibles such as project mandates that embody the project essentials (enacted reality), and responsiveness to the dynamics of the wider social context (external dynamics – peripety).

Research limitations/implications

It is apparent that the process of project formation, and the shape each project takes, is highly dependent on the actions of key individuals (shapers' volition). There is further scope for expanding the understanding, within the structure of the framework, of the full array of activities performed by individuals in action as “project shapers”.

Practical implications

The framework developed is of immediate value to those individuals who use their skills to mould a project, providing a conceptual basis they can use to learn and extend their skills.

Originality/value

Much of the interest to date in project formation has focused on instrumental managerial practices of governance. This paper focuses on lessons to be learned from the actuality of project formation – the conversion of work in organisations from a muddle of ambiguity and complexity into that particular form of cohesion and accepted “sense” that is a defined project or programme.