bluuebunny/crossref_metadata_2025 huggingface dataset:
Post‐bureaucracy – control through professional freedom
Authors: Maravelias Christian
Published: September 2003

This article develops a framework for understanding autonomy and control in post‐bureaucratic organizations. It reviews two dominant discourses on post‐bureaucracy – the managerial discourse and the critical management discourse. Whereas the one pictures post‐bureaucracy as an emancipating regime based on the personalities and social networks of individuals, the other pictures it as a totalitarian regime, which subordinates individuals’ thoughts, emotions and identities to its instrumental schemes. Both discourses are criticized for being grounded in a view of post‐bureaucracy as a “total” organization. An alternative conceptualization is developed, which shows that post‐bureaucracy neither emancipates individuals from control, nor captures them in totalitarian control. A distinguishing characteristic of post‐bureaucracy is that it displaces the responsibility for setting limits between professional and non‐professional concerns from the organization to the individual. Via a case study it is shown how this implies a specific form of control that does not restrict individual freedom, but uses it as its prime vehicle.
Fixing the language of change? A response
Authors: Collins David
Published: September 2003

Offers a response to a discussion of the language of change, which appeared in an earlier issue ofJOCM(Vol. 14, 2001).While applauding any attempt to develop an appreciation of the fluidity of the processes and politics of organizational change offers a critical response to the account of the language of change, which was prepared by Butcher and Atkinson. This critical response argues that Butcher and Atkinson's attempt to adjust and correct the language of change produces a rather conservative modelling of both management and organizational dynamics. Taking issue with this analysis argues that: Butcher and Atkinson continue to impoverish our understanding of organizational dynamics because they mix (and muddle) opposing and contradictory accounts of language in an attempt to refine an essentially managerialist change agenda; and their account of organizational dynamics produces a fixed and overly‐stabilized appreciation of change, which restricts and diminishes our understanding of the processes of change.
An exploratory study of Internet adoption by SMEs in an emerging market economy
Authors: Kula Veysel , Tatoglu Ekrem
Published: September 2003

This paper investigates the nature and extent of Internet use and the role of firm‐ and industry‐specific factors affecting Internet adoption by SMEs in an emerging market economy, Turkey. Based on the evidence from a sample of 237 manufacturing SMEs with Internet access in Turkey, the highest ranked Internet applications with the largest frequency of usage were found to be principally concerned with external communication and gathering information for market and product research. Of the five relevant firm‐ and industry‐specific subgroups, the most significant differences were found for two of the characteristics: amount of resources allocated for export development and international experience of the SME. In general, the SMEs have positive attitudes regarding Internet use. The SMEs are of the opinion that the Internet will become more attractive in future in terms of enhancing company image and being an important tool of doing business electronically.
How can a flexible labour market influence the amount of foreign direct investment attracted by a host nation? The case of the UK
Authors: Floyd David
Published: September 2003

It has often been suggested that Britain’s favourable position of attracting over 30 per cent of Japanese foreign direct investment (FDI) has been dependent on the flexibility of the labour market. However it is important to understand exactly what is meant by a flexible labour market. This article sets out to examine the full meaning of a flexible labour market drawing on the evidence of particular success in attracting FDI in the UK. It then considers the importance of the flexible labour market in relation to other possible factors influencing the decision whether to invest. Also advises of the benefit and costs for other countries wishing to formulate policies that attract greater amounts of FDI.
Directions in British Columbia wine tourism policy
Authors: Martin Elisa , Williams Peter
Published: September 2003

This paper identifies policies that have played influential roles in shaping British Columbia’s wine tourism value chain. It identifies those policies that have moulded the province’s current approach to wine tourism attraction development and resource protection in the Okanagan Valley. It suggests that significant progress has been made in the development of responsible and responsive polices related to these two components of the wine tourism value chain. However, it recommends that policies need to be created at the municipal level so that future wine tourism development protects the integrity and sustainable use of the region’s natural resource base.
The E‐MBA action learning: lessons for hospitality leaders
Authors: Cox Michael
Published: September 2003

E‐MBAs are becoming an attractive option for career professionals and organizations in the hospitality and tourism industry to build competitive advantage. As core faculty in the distance MBA program in The School of Hospitality and Tourism Management at the University of Guelph, the development of the E‐MBA has provided valuable lessons for leaders to understand how e‐learning builds leadership competency and capability in hospitality and tourism organizations. The research behind the action learning leadership framework is founded on the extensive work of the author at the University of Guelph. The author has pioneered distance MBA and leadership programs using the Internet to link people, knowledge and strategy with IT to build leadership competencies and online learning communities for managing in the knowledge‐based era. Evidence of this can be seen in a “virtual tour” of the distance MBA program at the following Website: www.emba.uoguelph.ca
Corporate performance management
Authors: Bourne Mike , Franco Monica , Wilkes John
Published: September 2003

Focuses on the changes in performance measurement, following research conducted with executives in a number of leading European companies. Found that there is a growing trend towards managing performance improvement through focusing on the underlying drivers of performance, whether improvements in the processes or the underlying resources that give these processes capability. The past obsession with pure financial performance is decreasing and there may be a recognition that there is a trade off between hitting today’s financial results and sustaining the capabilities and competences that allow companies to compete effectively in the future.
Better budgeting or beyond budgeting?
Authors: Neely Andy , Bourne Mike , Adams Chris
Published: September 2003

There is massive interest within the financial community in ways of improving and shortcutting the arduous process of planning and budgeting. Sponsored by Accenture, researchers at Cranfield School of Management’s Centre for Business Performance reviewed the literature and interviewed 15 leading companies to obtain insights into the best practices organizations are actually adopting. While some companies have simply exorcised the term budgeting from their corporate vocabularies, a group of pioneering Scandinavian companies have dispensed with budgeting altogether.
Copyright: its implications for electronic information
Authors: Subba Rao Siriginidi
Published: September 2003

This paper presents an overview of copyright, its history, and implications for electronic and multimedia. The international treaties on copyright are listed and the status of copyright protection in select countries is covered, including copyright law enactment, term, scope, sanctions, percentage of piracy and revenue loss in software piracy. Copyright issues for e‐information, the Internet and library and information centres are discussed. Digital copyright protection technologies – ECMS, watermarks, fingerprints and digital signatures, etc. – are described. It is concluded that copyright law has not disappeared with the evolution of technology and the development of a globalised IPR regime is recommended.
Self‐perception of competence in Korean children: Age, sex and home influences
Authors: Lee Julie , Super Charles M. , Harkness Sara
Published: September 2003

The self‐perceived competence of 750 Korean children in kindergarten through the seventh grade was investigated using adaptations of Harter's scales for younger and older children. Measures of family characteristics and the home environment were collected to explore the determinants of variation in self‐perceived competence. Adaptations of the competence scales yielded maximum similarity of content across the full age span, and also reflected the Korean emphasis on collectivist, intergenerational social skills and on early, direct training in academic cognitive skills. The results replicate two findings reported for North American and European samples; namely, increasing differentiation of domains of self‐perceived competence with age, and decreasing levels of self‐perceived competence in the opening years of primary school. In addition, the present study also finds two phenomena not evident in previous reports. First, a significant statistical interaction of grade and sex in the cognitive and physical domain was found, such that girls’ self‐perceived competence decreased more with age than did that of boys. Second, two social domains were differentiated, one reflecting peer acceptance (like the Harter scales) and the other tapping intergenerational and collectivist social skills that are valued in Korean society. Structural equation modeling revealed different patterns of influence for the four outcome measures. Both the analysis of internal variation and comparison with previous reports highlight the importance of a social and cultural perspective in understanding the development of children's self‐perceived competence.
Investigation of the relationship between social isolation, self‐esteem, aggression and computer game play in Japanese adolescents
Authors: Colwell John , Kato Makiko
Published: September 2003

Some support for expressed concern over the negative consequences of computer game play was obtained by Colwell and Payne (2000) in a questionnaire survey of UK adolescents. A second study was carried out in Tokyo, Japan, to test for generality of findings. There was strong evidence of similarity in relation to play patterns, but in contrast to the UK sample, number of good friends and self‐esteem did not relate to game play. A principal components analysis of a scale to measure needs met by game play resulted in the same two previously obtained factors; ‘companionship’ and ‘prefer to friends’. However, in contrast to the UK sample, ‘companionship’ did not relate to play. A positive relation between the ‘prefer to friends’ factor and play was obtained for both boys and girls (boys only in the UK), thus providing support for the ‘electronic friendship’ hypothesis. There was evidence of a positive relation between play and aggression, but a preference for aggressive games was associated with lower aggression scores, and this raises questions for the ‘causal hypothesis’.
Power and Competition in the UK Retail Grocery Market
Authors: Burt Steve L. , Sparks Leigh
Published: September 2003

The UK retail grocery market is widely recognized as being oligopolistic. This has raised concerns over the level and use of power by the leading retailers. This paper considers the changes in the UK retail grocery market in the context of a discussion of power. This discussion focuses on the possibility of a dominant chain arising in the market. Vertical and horizontal relationships and price and non‐price competition form the organizing principles of the analysis. Policy implications are suggested and other conclusions are drawn.
Special Economic Zones in Developing and/or Transition Economies: a Policy Proposal
Authors: Schweinberger Albert G.
Published: September 2003

Making use of a global partitioning (disintegration) approach, a novel necessary and sufficient condition for the creation of Pareto‐improving special economic zones is derived. It is shown that the establishment of a special economic zone may be desirable even if foreign investment has an immiserization effect. The present approach allows not only for the use of mobile but also immobile domestically owned factors in the special economic zone. Adopting a political economy perspective, multihousehold economies with and without the feasibility of lump‐sum compensation are modeled. It is shown that, subject to a certain condition, the setting up of special economic zones accompanied by appropriate tax policies results in an increase in government revenue. The latter may be used to finance much‐needed investment in infrastructure or the production of public goods.
The Lens Condition with Two Factors
Authors: Wong Siu‐kee , Yun Kwan Koo
Published: September 2003

The authors give a simple, constructive proof that the lens condition implies the factor price equalization condition when there are only two factors. Taking stock of the conditions under which the lens condition is equivalent to the factor price equalization condition, there are the conditions of two factors or two goods or two countries, or the condition that the rank of the factor‐use matrix is equal to the number of goods. It is shown that, in an essential sense, there are no other such conditions.
Developing‐Country Benefits from MFN Relative to Regional/Bilateral Trade Arrangements
Authors: Ghosh Madanmohan , Perroni Carlo , Whalley John
Published: September 2003

Using a general‐equilibrium model of world trade, this paper evaluates the benefits of most‐favored‐nation (MFN) treatment to developing countries in multilateral relative to bilateral or regional trade agreements, from three sources. First, developing countries may be able to free‐ride on bilateral tariff concessions exchanged between larger countries in MFN‐based GATT/WTO rounds. Second, MFN benefits developing countries by restricting discriminatory retaliatory actions by other countries, evaluated here by a non‐ cooperative Nash tariff game. Finally, MFN changes threat points in bargaining and hence affects the bargaining solution of multilateral MFN‐based trade negotiation compared to a bilateral/regional arrangement. The authors find that the benefits to developing countries are small in the first case as the tariff rates are already low, and the benefits are small in the second case as the optimal tariffs under unconstrained retaliation are not very asymmetric. Benefits from the third case are large as large countries can extract large side‐payments if they bargain bilaterally.
Detecting Effects of Living Wage Laws
Authors: Neumark David , Adams Scott
Published: September 2003

We estimate the effects of living wage laws on wages of low‐wage workers, focusing on the timing of policy, spurious associations, and the type of living wage law passed in a city. Our estimates point to sizable positive wage effects in cities with broad living wage laws that cover employers receiving business assistance from the city. We also explore disemployment effects of living wage laws and find evidence consistent with tradeoffs between wages and employment.
What Do Unions Do to Productivity? A Meta‐Analysis
Authors: Doucouliagos Christos , Laroche Patrice
Published: September 2003

The impact of unions on productivity is explored using meta‐analysis and meta‐regression analysis. It is shown that most of the variation in published results is due to specification differences between studies. After controlling for differences between studies, a negative association between unions and productivity is established for the United Kingdom, whereas a positive association is established for the United States in general and for U.S. manufacturing.
Cash Balance Plans and the Distribution of Pension Wealth
Authors: Johnson Richard W. , Uccello Cori E.
Published: September 2003

Recent pension plan conversions by numerous large employers have sparked debate about the merits of cash balance plans. This article compares pension wealth in traditional defined benefit (DB) plans and cash balance plans for a national sample of covered Americans aged 51 to 61. The simulations indicate that replacing DB plans with cash balance plans would redistribute pension wealth from those with long‐term jobs to those with multiple short‐term jobs and from those with substantial pension benefits to those with more limited benefits. Perhaps unexpectedly, women at midlife in 1992 with DB coverage would lose wealth in cash balance plans, but future cohorts of women are likely to fare better.
Possibilities for remote participation in trade unions: mobilising women activists
Authors: Greene Anne‐marie , Kirton Gill
Published: September 2003

This paper argues that trade union activism within the new era of information and communication technologies (ICTs) offers the potential for unions to become more inclusive of under‐represented groups. Traditional conceptions of activism, participation and democracy within trade unions require physical presence at meetings at times and in spaces incompatible with caring responsibilities and atypical hours of work. This restricts the participation of women and other ‘atypical’ workers in trade unions. The paper explores the complexities of electronic forms of union activism in practice, indicating that while some positive features are experienced, there are also a range of obstacles, barriers and possible negative consequences.
Motor Unit Properties in the Soleus Muscle after Its Distal Tendon Transfer to the Plantaris Muscle Tendon in the Rat
Authors: Giroux‐Metges Marie‐Agnès , Pennec Jean‐Pierre , Petit Julien , Goanvec Christelle , Dorange Germaine , Gioux Maxime
Published: September 2003

The aim of this study was to evaluate how a modification in the mechanical conditions under which a muscle is used could induce changes in the characteristics and the spinal drive of its motor units (MU). The distal tendon of the soleus muscle of Wistar rats was transferred to the distal stump of the plantaris muscle tendon. The EMG activity of the soleus was chronically recorded for 8 weeks, every other day, during a 1‐min treadmill walk. After spinal ventral root splitting, individual MU contractile properties were measured in control soleus (102 MUs) or in transposed soleus muscles after 4 weeks (41 MUs) or 8 weeks (28 MUs). Muscle/body weight ratio did not vary after transposition, nor did MU tetanic forces. A decrease in MU twitch contraction times and in their half relaxation times was observed at weeks 4 and 8. MU tension‐frequency curves varied significantly after tendon transfer, becoming closer to the curves of the fast MUs of the control group. During locomotion, we observed no change in the amplitude of rectified‐filtered electromyographic activity, but a significant decrease in mean burst duration and an increase in the median frequency of the power density spectrum. Tendon transposition of the soleus muscle brought about adaptations in MU contractile properties and soleus spinal control.
Comparative genomic analysis as a tool for biological discovery
Authors: Nobrega Marcelo A. , Pennacchio Len A.
Published: September 2003

The recent completion of the human genome sequence has enabled the identification of a large fraction of our gene catalogue and their physical chromosomal position. However, current efforts lag at defining the cis‐regulatory sequences that control the spatial and temporal patterns of each gene's expression. This task remains difficult due to our lack of knowledge of the vocabulary controlling gene regulation and the vast genomic search space, with greater than 95% of our genome being noncoding. Recent comparative genomic‐based strategies are beginning to aid in the identification of functional sequences based on their high levels of evolutionary conservation. This has proven successful for comparisons between closely related species such as human–primate or human–mouse, but also holds true for distant evolutionary comparisons, such as human–fish or human–bird. In this review we provide support for the utility of cross‐species sequence comparisons by illustrating several applications of this strategy, including the identification of new genes and functional non‐coding sequences. We also discuss emerging concepts as this field matures, such as how to properly select which species for comparison, which may differ significantly between independent studies.
Kinetic properties of the α2 homo‐oligomeric glycine receptor impairs a proper synaptic functioning
Authors: Mangin J. M. , Baloul M. , Prado de Carvalho L. , Rogister B. , Rigo J. M. , Legendre P.
Published: September 2003

Ionotropic glycine receptors (GlyRs) are present in the central nervous system well before the establishment of synaptic contacts. Immature nerve cells are known, at least in the spinal cord, to express α2 homomeric GlyRs, the properties of which are relatively unknown compared to those of the adult synaptic form of the GlyR (mainly α1/β heteromeres). Here, the kinetics properties of GlyRs at the single‐channel level have been recorded in real‐time by means of the patch‐clamp technique in the outside‐out configuration coupled with an ultra‐fast flow application system (< 100 µs). Recordings were performed on chinese hamster ovary (CHO) cells stably transfected with the α2 GlyR subunit. We show that the onset, the relaxation and the desensitisation of α2 homomeric GlyR‐mediated currents are slower by one or two orders of magnitude compared to synaptic mature GlyRs and to other ligand‐gated ionotropic channels involved in fast synaptic transmission. First latency analysis performed on single GlyR channels revealed that their slow activation time course was due to delayed openings. When synaptic release of glycine was mimicked (1 mm glycine; 1 ms pulse duration), the opening probability of α2 homomeric GlyRs was low (Po≈ 0.1) when compared to mature synaptic GlyRs (Po= 0.9). This low Po is likely to be a direct consequence of the relatively slow activation kinetics of α2 homomeric GlyRs when compared to the activation kinetics of mature α1/β GlyRs. Such slow kinetics suggest that embryonic α2 homomeric GlyRs cannot be activated by fast neurotransmitter release at mature synapses but rather could be suited for a non‐synaptic paracrine‐like release of agonist, which is known to occur in the embryo.
RelA Is a Component of the Nutritional Stress Activation Pathway of theBacillus subtilisTranscription Factor σB
Authors: Zhang Shuyu , Haldenwang W. G.
Published: September 2003

The general stress regulon ofBacillus subtilisis induced by the activation of the σBtranscription factor. Activation of σBoccurs when one of two phosphatases (RsbU and RsbP), each responding to a unique type of stress, actuates a positive regulator of σBby dephosphorylation. Nutritional stress triggers the RsbP phosphatase. The mechanism by which RsbP becomes active is unknown; however, its activation coincides with culture conditions that are likely to reduce the cell's levels of high-energy nucleotides. We now present evidence that RelA, a (p)ppGpp synthetase and the key enzyme of the stringent response, plays a role in nutritional stress activation of σB. An insertion mutation that disruptsrelAblocks the activation of σBin response to PO4or glucose limitation and inhibits the drop in ATP/GTP levels that normally accompanies σBinduction under these conditions. In contrast, the activation of σBby physical stress (e.g., ethanol treatment) is not affected by the loss of RelA. RelA's role in σBactivation appears to be distinct from its participation in the stringent response. Amino acid analogs which induce the stringent response and RelA-dependent (p)ppGpp synthesis do not trigger σBactivity. In addition, neither a missense mutation inrelA(relA240GE) nor a null mutation inrplK(rplK54), either of which is sufficient to inhibit the stringent response and RelA-dependent (p)ppGpp synthesis, fails to block σBactivation by PO4or glucose limitation.
Erwinia chrysanthemi tolCIs Involved in Resistance to Antimicrobial Plant Chemicals and Is Essential for Phytopathogenesis†
Authors: Barabote Ravi D. , Johnson Oswald L. , Zetina Eric , San Francisco Susan K. , Fralick Joe A. , San Francisco Michael J. D.
Published: September 2003

TolC is the outer-membrane component of several multidrug resistance (MDR) efflux pumps and plays an important role in the survival and virulence of many gram-negative bacterial animal pathogens. We have identified and characterized the outer-membrane protein-encoding genetolCin the bacterial plant pathogenErwinia chrysanthemiEC16. The gene was found to encode a 51-kDa protein with 70% identity to itsEscherichia colihomologue. TheE. chrysanthemigene was able to functionally complement theE. coli tolCgene with respect to its role in MDR efflux pumps. AtolCmutant ofE. chrysanthemiwas found to be extremely sensitive to antimicrobial agents, including several plant-derived chemicals. This mutant was unable to grow in planta and its ability to cause plant tissue maceration was severely compromised. ThetolCmutant was shown to be defective in the efflux of berberine, a model antimicrobial plant chemical. These results suggest that by conferring resistance to the antimicrobial compounds produced by plants, theE. chrysanthemi tolCplays an important role in the survival and colonization of the pathogen in plant tissue.
The Naphthalene Catabolic (
nag
) Genes of
Ralstonia
sp. Strain U2 Are an Operon That Is Regulated by NagR, a LysR-Type Transcriptional Regulator
Authors: Jones Rheinallt M. , Britt-Compton Bethan , Williams Peter A.
Published: September 2003

In
Ralstonia
sp. strain U2, the
nag
catabolic genes, which encode the enzymes for the pathway that catabolizes naphthalene via the alternative ring cleavage gentisate pathway, are transcribed as an operon under the same promoter.
nagR
, which encodes a LysR-type transcriptional regulator, is divergently transcribed compared to the
nag
catabolic genes. A 4-bp frameshift deletion in
nagR
demonstrated that NagR is required for expression of the
nag
operon. The transcriptional start of the
nag
operon was mapped, and a putative −10, −35 σ
70
-type promoter binding site was identified. Further upstream, a site proximal to the promoter was identified as a site that has bases which have been found to be conserved in the activator-binding motif of other naphthalene pathways. Transcriptional fusion studies demonstrated that NagR regulates the expression of the
nag
operon positively in the presence of salicylate and to a lesser extent in the presence of 2-nitrobenzoate. Mutation of the LysR-type activator-binding motif in the
nag
promoter-proximal region resulted in a loss of inducibility of a
lacZ
reporter gene transcriptionally fused to
nagAa
, the first gene of the operon. However, other mutations in the region increased the effectiveness of salicylate as an inducer.
Dual Overlapping Promoters ControlnapF(Periplasmic Nitrate Reductase) Operon Expression inEscherichia coliK-12
Authors: Stewart Valley , Bledsoe Peggy J. , Williams Stanly B.
Published: September 2003

Escherichia colielaborates a flexible respiratory metabolism, involving differential synthesis of isoenzymes for many oxidation and reduction reactions. Periplasmic nitrate reductase, encoded by thenapFDAGHBCoperon, functions with concentrations of nitrate that are too low to support respiration by membrane-bound nitrate reductase. ThenapFoperon control region exhibits unusual organization of DNA binding sites for the transcription regulators Fnr and NarP, which activate transcription in response to anaerobiosis and nitrate, respectively. Previous studies have shown that thenapFoperon control region directs synthesis of two transcripts whose 5′ ends differ by about 3 nucleotides. We constructed mutant control regions in which either of the two promoter −10 regions is inactivated. Results indicate that the downstream promoter (P1) was responsible for Fnr- and NarP-regulatednapFoperon expression, whereas transcription from the upstream promoter (P2) was activated only weakly by the Fnr protein and was inhibited by phospho-NarP and -NarL proteins. The physiological function of promoter P2 is unknown. These results establish the unconventionalnapFoperon control region architecture, in which the major promoter P1 is activated by the Fnr protein bound to a site centered at −64.5 with respect to the transcription initiation site, working in conjunction with the phospho-NarP protein bound to a site centered at −44.5.
Characterization and Regulation of the Genes for a Novel Anthranilate 1,2-Dioxygenase from
Burkholderia cepacia
DBO1
Authors: Chang Hung-Kuang , Mohseni Paria , Zylstra Gerben J.
Published: September 2003

Anthranilate (2-aminobenzoate) is an important intermediate in tryptophan metabolism. In order to investigate the degradation of tryptophan through anthranilate by
Burkholderia cepacia
, several plasposon mutations were constructed of strain DBO1 and one mutant with the plasposon insertion in the anthranilate dioxygenase (AntDO) genes was chosen for further study. The gene sequence obtained from flanking DNA of the plasposon insertion site revealed unexpected information.
B. cepacia
DBO1 AntDO (designated AntDO-3C) is a three-component Rieske-type [2Fe-2S] dioxygenase composed of a reductase (AndAa), a ferredoxin (AndAb), and a two-subunit oxygenase (AndAcAd). This is in contrast to the two-component (an oxygenase and a reductase) AntDO enzyme from
Acinetobacter
sp. strain ADP1,
P. aeruginosa
PAO1, and
P. putida
P111. AntDO from strains ADP1, PAO1, and P111 are closely related to benzoate dioxygenase, while AntDO-3C is closely related to aromatic hydrocarbon dioxygenases from
Novosphingobium aromaticivorans
F199 and
Sphingomonas yanoikuyae
B1 and 2-chlorobenzoate dioxygenase from
P. aeruginosa
strains 142 and JB2.
Escherichia coli
cells expressing the functional AntDO-3C genes transform anthranilate and salicylate (but not 2-chlorobenzoate) to catechol. The enzyme includes a novel reductase whose absence results in less efficient transformation of anthranilate by the oxygenase and ferredoxin. AndR, a possible AraC/XylS-type transcriptional regulator, was shown to positively regulate expression of the
andAcAdAbAa
genes. Anthranilate was the only effector (of 12 aromatic compounds tested) that was able to induce expression of the genes.
Eliashberg Theory of the Superconducting State of Marginal Fermi Liquids
Authors: Choi Han-Yong , Yoo Jung-Woo
Published: September 2003

The marginal Fermi liquid (MFL) which describes the anomalous normal state of the cuprates is extended to a d-wave superconductive state. A phenomenological collective excitation, P0(ω,T), is taken such that it gives rise to, after renormalization, the MFL behavior in the normal state. With the P0, the renormalized excitation spectrum and pairing function in superconductive state are calculated self-consistently within the Eliashberg formalism. In the superconductive state, the self-energy deviates from the normal state MFL ω/T-scaling and develops a new energy scale of ω0≈2Δ, where Δ is the pairing amplitude.
Mirror Nesting and High TC Superconductivity
Authors: Belyavsky V. I. , Kapaev V. V. , Kopaev Yu. V.
Published: September 2003

The necessary condition of superconducting pairing with large total pair momentum is mirror nesting that is a rise of pair Fermi contour due to matching of some pieces of the Fermi contour and an isoline of the pair-relative-motion kinetic energy. Such a condition may be satisfied, at definite total pair momenta, due to a special feature of electron dispersion. In the case of perfect mirror nesting a rise of the superconducting ordering turns out to be possible up to arbitrary small value of the pairing interaction strength.
Vibronic Mechanism of High Tc Superconductivity
Authors: Tachiki M. , Egami T. , Machida M.
Published: September 2003

When phonons strongly mix with electron charge fluctuations with low frequencies, the phonon mediated attractive interaction between electrons is strongly enhanced. The occurrence of the mixing has been indicated by the neutron scattering experimental results that the dispersion of the in-plane Cu–O bond-stretching mode in the high Tc cuprate superconductors is strongly softened near the zone boundary. We propose that the phonon mediated attractive interaction strongly enhanced by the vibronic effect can form a basis for the phonon mechanism of high temperature superconductivity. With the Eliashberg theory and with the electronic structure determined by ARPES and the electronic dielectric function obtained by the softened dispersion of the in-pane Cu–O stretching mode, we calculated the transition temperature and the order parameter at the transition temperature. The order parameter is of the d(x2-y2) symmetry and the transition temperature is well in excess of 100 K.
Qualitative Picture of a New Mechanism for High-Tc Superconductors
Authors: Hu Chia-Ren
Published: September 2003

Xu et al. observed enhanced Nernst effect and Iguchi et al. observed patched diamagnetism, both well above Tc in underdoped high-Tc superconductors (HTSCs). A new mechanism is proposed here, which seems to naturally explain, at least qualitatively, these observations, as well as the d-wave nature and continuity of pseudogap and pairing gap, the tunneling conductance above Tc, as well as T*(x), Tν(x), Tc(x), etc. This mechanism combines features of dynamic charged stripes, preformed pairs, and spin-bags: At appropriete doping levels, the doped holes (and perhaps also electrons) will promote the formation of anti-phase islands in short-range anti-ferromagnetic order. On the boundary of each such island reside two doped carriers; the unscreened Coulomb repulsion between them stabilizes the island's size. Superconductivity results when such "pre-formed pairs" Bose-condense.
Role of Spinon Excitations on KT Transition at Low Energies in d-Wave Superconductors
Authors: Kim Ki-Seok , Seo Young-Il , Eom Jae-Hyeon , Lee Sung-Sik , Eom Jae-Gon , Salk Sung-Ho Suck
Published: September 2003

By using a low energy effective Lagrangian of the U(1) slave boson mean field theory we examine the vortex binding-unbinding transition (KT transition) from a doped Mott insulator at low temperatures in a d-wave superconductor. It is shown that the interaction potential between vortices is modified by a "Doppler energy shift" resulting in additional attractive interaction, as a consequence of supercurrent fluctuations coupled to the particle-hole excitations of the massless Dirac fermions.
Charge Distribution in La2-xSrxCuO4
Authors: Stoll E. P. , Meier P. F. , Claxton T. A.
Published: September 2003

The electronic structure of La 2 CuO 4 has been studied by first-principles cluster calculations before and after doping. Clusters containing up to five planar copper atoms were investigated using the density functional method. At variance with band-structure calculations, we have been able to determine the charge and spin distributions from molecular orbitals expressed as linear combinations of atomic orbitals localised at the nuclear sites. Doping is achieved by subtracting an electron from the cluster which, although there is a change of spin state, produces a charge distribution which is remarkably similar to the charge distribution of the peripheral charge method which does not involve changes in spin state. The peripheral charge method is designed to simulate doping by placing a carefully chosen set of point charges beyond the periphery of the cluster and relies on the supposition that the hole distribution is closely related to the charge distribution. More importantly the peripheral charge method enables charge distribution changes to be obtained for fractional changes in doping. The results show that with fixed nuclear positions, doping not only depopulates the 2pσ orbitals but also affects other orbitals. This redistribution of charges influences the electric field gradients and hyperfine coupling parameters. The theoretical values for the field gradients are compared to values derived from experiments.
Thermodynamic Properties of One-Dimensional Hubbard Model at Finite Temperatures
Authors: Yang C. , Kocharian A. N. , Chiang Y. L.
Published: September 2003

The phase diagram and thermodynamic properties of the Hubbard model in one dimension are calculated numerically within the generalized self-consistent approach over a wide range of temperature T, magnetic field h, interaction strength U/t and electron concentration n. The temperature variation of the transverse magnetization, double occupied sites and chemical potential at various n, U/t and h is also analyzed. The wave vector q for the magnetic order parameter in the vicinity of the half-filling in the metallic phase shows a crossover from incommensurate magnetic phase (0<q<π) into the state with strong antiferromagnetic correlations (q=π) as temperature is increased. Overall our numerical results in the approximate theory at finite temperatures are in good quantitative and qualitative agreement with the Bethe-ansatz results.
Spin-Charge Gauge Theory of "Pseudogap": Theory Versus Experiments
Authors: Marchetti P. A. , Su Z. B. , Yu L.
Published: September 2003

We propose an explanation of several experimental features related to the "pseudogap" in high Tc cuprates in terms of a spin-charge gauge theory. In this approach, based on a formal spin-charge separation applied to the t-J model, the low energy effective action describes gapful spinons (with a theoretically derived doping dependence of the gap ms~J(δ| ln δ|)1/2, where δ is the doping concentration) and holons with "small" Fermi surface (∊F~tδ) interacting via a gauge field. The main effect of gauge fluctuations is to introduce a dissipation ~T/χ, where χ is the diamagnetic susceptibility. The competition between the two energy scales, ms and T/χ, is the root in our approach of many phenomena peculiar to in-plane transport properties of the "pseudogap phase". Furthermore the gauge interaction induces binding of spinon and holon into an "electron" resonance. This binding introduces another energy scale, the recombination rate, which dominates the out-of-plane resistivity, yielding an insulating behavior. A good agreement is found between the experimental data and theoretically derived doping and temperature dependence of resistivity, both in-plane and out-of-plane, and spin relaxation.
Superconductivity in Two-Band Model by Renormalization Group Approach
Authors: Nagao Hidemi , Kawabe Hiroyuki , Kruchinin Sergei P. , Yamaguchi Kizashi
Published: September 2003

We investigate the superconductivity in a two-band model by using the renormalization group approach. We discuss the superconducting gap function in the two-band model.
Quantum Fluctuations and Vortex Phase Diagram in Uniformly Disordered Amorphous Films
Authors: Okuma S. , Togo S. , Morita M. , Saito F. , Amemori K.
Published: September 2003

We have studied effects of microscopic disorder (normal-state resistivity ρn) and dimensionality (film thickness t) on the vortex phase diagram at low temperature T on the basis of measurements of DC and AC complex resistivities for amorphous (a)- Mo x Si 1-x films with different ρn and t. For thick films (t=100 nm ) we have commonly observed the vortex-glass transition (VGT) down to low T~0.05Tc0 and high fields up to B~0.9Bc2(0), where Tc0 and Bc2(0) are the mean-field transition temperature and upper critical field at T=0, respectively. In the limit T=0, the VGT line Bg(T) is independent of T and extrapolates to a field below Bc2(0), indicative of the presence of a quantum-vortex-liquid (QVL) phase at T=0 in the regime Bg(0)<B<Bc2(0). We find that the width of the T=0 QVL phase, [Bc2(0)-Bg(0)]/Bc2(0), grows as the film becomes more resistive. This result is consistent with the view that the QVL phase is driven by strong quantum fluctuations, which are enhanced with increasing disorder. In the mixed state of the 6-nm-thick film, both the DC resistivity and vortex relaxation time follow the activated T dependence, suggestive of two-dimensional VGT.
Vortex Lattice Structure of High Temperature Superconductors
Authors: Zhou Shi-Ping , Du Hao-Chen , Liao Hong-Yin
Published: September 2003

We study vortex lattice structure of high temperature superconductors by using the Ginzburg–Landau model. The structure of the vortex lattice is oblique at the temperatures well below the transition temperature Tc, where the mixed s–d state is expected to have the lowest energy. Whereas, very close to Tc, the dx2-y2wave is slightly lower in energy, and a triangular vortex lattice recovers. The coexistence and the coupling between the s- and d-waves account for the upward curvature of the upper critical field curve HC2(T).
Effect of Disorder on Driven Vortex Matter in High-Tc Superconductors
Authors: Chen Qing-Hu , Hu Xiao
Published: September 2003

We performed large-scale simulations in the current-driven three-dimensional frustrated anisotropic XY model in the presense of point-like defects with resistively-shunted junction dynamics. A moving Bragg (BrG) glass is observed applying the current in the equilibrium BrG state. The first-order phase transition from the moving BrG to the moving smectic is clarified. The effect of disorder become weak once the vortex matter is set in motion.
Electrical Transport and Oxygen Disorder in YBCO
Authors: Jung J. , Abdelhadi M. M.
Published: September 2003

We investigated the origin of a non-linear temperature dependence of resistivity ρab(T) in the a-b planes of YBCO, frequently observed in optimally doped twinned YBCO single crystals and thin films and in untwinned YBCO crystals along the chain direction. We performed the measurements of ρab(T) in c-axis oriented YBCO thin films that were subjected to low temperature annealing at 120–140°C (400–420 K) in argon. Our results have shown that redistribution of oxygen at a fixed oxygen content in the chain layers of YBCO with a non-linear ρab(T), leads to an increase of Tc, an increase of resistivity and a reduction of the non-linear component in ρab(T).
Effects of Magnetic Collective Modes in the Tunneling Spectra of High-Tc Superconductors
Authors: Zhu Jian-Xin , Balatsky A. V. , Sun Jun , Si Qimiao
Published: September 2003

High-energy spin collective modes are often observed in inelastic neutron scattering experiments for high-temperature superconductors. Motivated by the recent scanning tunneling microscopy (STM) observation of the "checkerboard" pattern in the tunneling conductance in superconducting Bi 2 Sr 2 CaCu 2 O 8+δ, we study the effects of these high-energy dynamic spin collective modes on the local density of states (LDOS). Unlike other scenarios recently proposed, we do not assume the pinning of the collective mode. The exchange coupling between the superconducting electrons and the collective modes produces high energy peaks in the LDOS. The spatial dependence of the LDOS at high resonant energy suggests a possible detection of resonant magnetic mode with the STM.
Tunneling Spectra of Inhomogeneous d-Wave Superconductor
Authors: Han Jung Hoon
Published: September 2003

The tunneling spectrum of an inhomogeneous d-wave superconductor is discussed in the framework of self-consistent slave-boson mean-field theory. Distinct from the usual BCS-type mean-field theory, an electron is now described using both fermionic and bosonic degree of freedom. We show that one can define two types of tunneling spectra in this theory, which also corresponds to two ways of calibrating the STM spectra. In good agreement with the experimental observation, we show that one type of tunneling spectrum remains inhomogeneous while the other type shows a remarkable degree of homogeneity at low energy, despite the underlying disorder. Physical implications of this result, in particular in relation to thermodynamic measurement such as heat capacity, are discussed.
Hall Anomaly Near Tc in YBa2Cu3O7-δ: Effects of Renormalized Superconducting Fluctuations and Pinning
Authors: Lang W. , Puica I. , Göb W. , Sobolewski Roman
Published: September 2003

The Hall effect in epitaxial YBa 2 Cu 3 O 7-x films in perpendicularly applied magnetic fields B from 1 to 6 T reveals a sign reversal of the Hall coefficient for B ≤ 3 T . We analyze our experimental data by using the full quantitative expressions based on the renormalized superconducting fluctuation model. We propose an approach how the vortex pinning can be considered in the Hall coefficient, based on the observation that flux pinning mainly affects the longitudinal conductivity in the low-temperature part of the superconducting transition.
Chemical Pressure-Induced Ferromagnetism and Stabilization of the Metallic State in Ba1-xSrxVS3
Authors: Gauzzi A. , Licci F. , Barišić N. , Calestani G. L. , Bolzoni F. , Gilioli E. , Marezio M. , Sanna A. , Franchini C. , Forró L.
Published: September 2003

Measurements of magnetization and of resistivity under pressure on Ba 1-x Sr x VS 3 single crystals show that Sr-induced chemical pressure progressively weakens the antiferromagnetic correlations responsible for the metal-insulator transition. The antiferromagnetic ordering temperature, TX = 30 K at x = 0, vanishes at x = 0.08. At larger x, a ferromagnetic order appears with TC = 21.5 K at x = 0.18. The key-parameter favoring the metallic state is found to be the compression of the VS 6 octahedra and we predict a metallic state at 0 K for a V–S distance of 2.33 Å. The stabilization effect of the metallic state provided by the chemical pressure is supported by first principles band structure calculations performed by using the Vienna ab initio simulation package (VASP) within the projector augmented–wave (PAW) method in the local density approximation (LDA) + U scheme.
Correlated Charge Excitations in Quasi-Low-Dimensional Mott Insulators
Authors: Hasan M. Z. , Chuang Y.-D. , Li Y. , Montano P. A. , Hussain Z. , Dhalenne G. , Revcolevschi A. , Eisaki H. , Motoyama N. , Uchida S.
Published: September 2003

We report momentum dependence of charge excitations across the effective Mott gap in quasi-low dimensional model cuprates with different effective dimensionalities ( CuGeO 3 and SrCuO 2), using high resolution inelastic X-ray scattering by working near a resonance. Particle-hole pair excitations at the gap edge in these compounds are found to be strongly dependent on the effective dimensionality of the lattice and the strength of electron–electron Coulomb interaction.
Field Anisotropy of the Pseudogap State in Bi2Sr2CaCu2O8+y Ultrahigh Magnetic Fields
Authors: Krusin-Elbaum L. , Shibauchi T. , Mielke C. H.
Published: September 2003

The orientational anisotropy of the pseudogap closing field Hpg is investigated in magnetic fields up to 60 T applied parallel (||ab) and normal (||c) to CuO 2 planes in Bi 2 Sr 2 CaCu 2 O 8+y. We find that, in contrast to large field anisotropy related to the orbital motion of Cooper pairs below the upper critical field Hc2, the temperature-independent and small anisotropy of Hpg is due to anisotropy of the g-factor: [Formula: see text], indicating correlations only in the spin-channel.
Structural Response to Local Charge Order in Underdoped but Superconducting La2-x(Sr,Ba)xCuO4
Authors: Billinge Simon J. L. , Gutmann Matthias , Božin Emil S.
Published: September 2003

Results are presented of a local structural study of the nearest neighbor Cu–O distance distribution in underdoped but superconducting La 1.875 Sr 0.125 CuO 4, La 1.85 Ba 0.15 CuO 4 and La 1.85 Sr 0.15 CuO 4. Atomic pair distribution function analysis of neutron powder diffraction data has been carried out to obtain local structural information over a wide temperature range. We observe an anomalous increase in the Cu–O bond length distribution at low temperature that may be associated with the presence of an inhomogeneous charge distribution. The increase at low temperature has an onset temperature which correlates with observations of charge and spin freezing seen by other probes.