bluuebunny/crossref_metadata_2025 huggingface dataset:
Biochemical Characterization of the Extracellular Phosphatases Produced by Phosphorus-Deprived Chlamydomonas reinhardtii
Authors: Quisel J. D. , Wykoff D. D. , Grossman A. R.
Published: July 2002

We have examined the extracellular phosphatases produced by the terrestrial green alga Chlamydomonas reinhardtii in response to phosphorus deprivation. Phosphorus-deprived cells increase extracellular alkaline phosphatase activity 300-fold relative to unstarved cells. The alkaline phosphatases are released into the medium by cell-wall-deficient strains and by wild-type cells after treatment with autolysin, indicating that they are localized to the periplasm. Anion-exchange chromatography and analysis by nondenaturing polyacrylamide gel electrophoresis revealed that there are two major inducible alkaline phosphatases. A calcium-dependent enzyme composed of 190-kD glycoprotein subunits accounts for 85 to 95% of the alkaline phosphatase activity. This phosphatase has optimal activity at pH 9.5 and a Km of 120 to 262 [mu]M for all physiological substrates tested, with the exception of phytic acid, which it cleaved with a 50-fold lower efficiency. An enzyme with optimal activity at pH 9 and no requirement for divalent cations accounts for 2 to 10% of the alkaline phosphatase activity. This phosphatase was only able to efficiently hydrolyze arylphosphates. The information reported here, in conjunction with the results of previous studies, defines the complement of extracellular phosphatases produced by phosphorus-deprived Chlamydomonas cells.
Molecular Characterization of Photomixotrophic Tobacco Cells Resistant to Protoporphyrinogen Oxidase-Inhibiting Herbicides
Authors: Watanabe Naohide , Che Fang-Sik , Iwano Megumi , Takayama Seiji , Nakano Takeshi , Yoshida Shigeo , Isogai Akira
Published: July 2002

Peroxidizing herbicides inhibit protoporphyrinogen oxidase (Protox), the last enzyme of the common branch of the chlorophyll- and heme-synthesis pathways. There are two isoenzymes of Protox, one of which is located in the plastid and the other in the mitochondria. Sequence analysis of the cloned Protox cDNAs showed that the deduced amino acid sequences of plastidial and mitochondrial Protox in wild-type cells and in herbicide-resistant YZI-1S cells are the same. The level of plastidial Protox mRNA was the same in both wild-type and YZI-1S cells, whereas the level of mitochondrial Protox mRNA YZI-1S cells was up to 10 times the level of wild-type cells. Wild-type cells were observed by fluorescence microscopy to emit strong autofluorescence from chlorophyll. Only a weak fluorescence signal was observed from chlorophyll in YZI-1S cells grown in the Protox inhibitorN-(4-chloro-2-fluoro-5-propagyloxy)-phenyl-3,4,5,6-tetrahydrophthalimide. Staining with DiOC6 showed no visible difference in the number or strength of fluorescence between wild-type and YZI-1S mitochondria. Electron micrography of YZI-1S cells showed that, in contrast to wild-type cells, the chloroplasts of YZI-1S cells grown in the presence ofN-(4-chloro-2-fluoro-5-propagyloxy)-phenyl-3,4,5,6-tetrahydrophthalimide exhibited no grana stacking. These results suggest that the herbicide resistance of YZI-1S cells is due to the overproduction of mitochondrial Protox.
Plastid Sedimentation Kinetics in Roots of Wild-Type and Starch-Deficient Mutants of Arabidopsis1
Authors: MacCleery Scott A. , Kiss John Z.
Published: July 2002

Sedimentation and movement of plastids in columella cells of the root cap were measured in seedlings of wild-type, a reduced starch mutant, and a starchless mutant of Arabidopsis. To assay for sedimentation, we used both linear measurements and the change of angle from the cell center as indices in vertical and reoriented plants with the aid of computer-assisted image analysis. Seedlings were fixed at short periods after reorientation, and plastid sedimentation correlated with starch content in the three strains of Arabidopsis. Amyloplasts of wild-type seedlings showed the greatest sedimentation, whereas plastids of the starchless mutant showed no significant sedimentation in the vertically grown and reoriented seedlings. Because previous research has shown that a full complement of starch is needed for full gravitropic sensitivity, this study correlates increased sensitivity with plastid sedimentation. However, although plastid sedimentation contributed to gravisensitivity, it was not required, because the gravitropic starchless mutant had plastids that did not sediment. This is the first study, to our knowledge, to measure plastid sedimentation in Arabidopsis roots after reorientation of seedlings. Taken together, the results of this study are consistent with the classic plastid-based and protoplast-based models of graviperception and suggest that multiple systems of perception exist in plant cells.
Vacuolar H+-ATPase Is Expressed in Response to Gibberellin during Tomato Seed Germination
Authors: Cooley Michael B. , Yang Hong , Dahal Peetambar , Mella R. Alejandra , Downie A. Bruce , Haigh Anthony M. , Bradford Kent J.
Published: July 2002

Completion of germination (radicle emergence) by gibberellin (GA)-deficient (gib-1) mutant tomato (Lycopersicon esculentum Mill.) seeds is dependent upon exogenous GA, because weakening of the endosperm tissue enclosing the radicle tip requires GA. To investigate genes that may be involved in endosperm weakening or embryo growth, differential cDNA display was used to identify mRNAs differentially expressed in gib-1 seeds imbibed in the presence or absence of GA4+7. Among these was a GA-responsive mRNA encoding the 16-kD hydrophobic subunit c of the V0 membrane sector of vacuolar H+-translocating ATPases (V-ATPase), which we termed LVA-P1. LVA-P1 mRNA expression in gib-1 seeds was dependent on GA and was particularly abundant in the micropylar region prior to radicle emergence. Both GA dependence and tissue localization ofLVA-P1 mRNA expression were confirmed directly in individual gib-1 seeds using tissue printing.LVA-P1 mRNA was also expressed in wild-type seeds during development and germination, independent of exogenous GA. Specific antisera detected protein subunits A and B of the cytoplasmic V1 sector of the V-ATPase holoenzyme complex ingib-1 seeds only in the presence of GA, and expression was localized to the micropylar region. The results suggest that V-ATPase plays a role in GA-regulated germination of tomato seeds.
Basipetal Auxin Transport Is Required for Gravitropism in Roots of Arabidopsis
Authors: Rashotte Aaron M. , Brady Shari R. , Reed Robyn C. , Ante Sandra J. , Muday Gloria K.
Published: July 2002

Auxin transport has been reported to occur in two distinct polarities, acropetally and basipetally, in two different root tissues. The goals of this study were to determine whether both polarities of indole-3-acetic acid (IAA) transport occur in roots of Arabidopsis and to determine which polarity controls the gravity response. Global application of the auxin transport inhibitor naphthylphthalamic acid (NPA) to roots blocked the gravity response, root waving, and root elongation. Immediately after the application of NPA, the root gravity response was completely blocked, as measured by an automated video digitizer. Basipetal [3H]IAA transport in Arabidopsis roots was inhibited by NPA, whereas the movement of [14C]benzoic acid was not affected. Inhibition of basipetal IAA transport by local application of NPA blocked the gravity response. Inhibition of acropetal IAA transport by application of NPA at the root-shoot junction only partially reduced the gravity response at high NPA concentrations. Excised root tips, which do not receive auxin from the shoot, exhibited a normal response to gravity. The Arabidopsis mutant eir1, which has agravitropic roots, exhibited reduced basipetal IAA transport but wild-type levels of acropetal IAA transport. These results support the hypothesis that basipetally transported IAA controls root gravitropism in Arabidopsis.
The rug3 Locus of Pea Encodes Plastidial Phosphoglucomutase
Authors: Harrison Christopher J. , Mould Ruth M. , Leech Mark J. , Johnson Susan A. , Turner Lynda , Schreck Sabine L. , Baird Kathleen M. , Jack Peter L. , Rawsthorne Stephen , Hedley Cliff L. , Wang Trevor L.
Published: July 2002

Two cDNA clones were isolated from pea (Pisum sativum L.) and their deduced amino acid sequences shown to have significant homology to phosphoglucomutases from eukaryotic and prokaryotic sources. The longer cDNA contained a putative transit-peptide-encoding sequence, supporting the hypothesis that the isolated clones represent the cytosolic and plastidial isoforms of phosphoglucomutase in pea. Plastid protein import assays confirmed that the putative plastidial isoform was targeted to the plastid stroma where it was proteolytically processed. Expression, co-segregation, linkage, and molecular analyses have confirmed that therug3 locus of pea encodes plastidial phosphoglucomutase. Mutations at this locus result in a near-starchless phenotype of the plant.
Genetic Enhancement of Fatty Acid Synthesis by Targeting Rat Liver ATP:Citrate Lyase into Plastids of Tobacco
Authors: Rangasamy Dhandapani , Ratledge Colin
Published: July 2002

ATP:citrate lyase (ACL) catalyzes the conversion of citrate to acetyl-coenzyme A (CoA) and oxaloacetate and is a key enzyme for lipid accumulation in mammals and oleaginous yeasts and fungi. To investigate whether heterologous ACL genes can be targeted and imported into the plastids of plants, a gene encoding a fusion protein of the rat liver ACL with the transit peptide for the small subunit of ribulose bisphosphate carboxylase was constructed and introduced into the genome of tobacco. This was sufficient to provide import of the heterologous protein into the plastids. In vitro assays of ACL in isolated plastids showed that the enzyme was active and synthesized acetyl-CoA. Overexpression of the rat ACL gene led to up to a 4-fold increase in the total ACL activity; this increased the amount of fatty acids by 16% but did not cause any major change in the fatty acid profile. Therefore, increasing the availability of acetyl-CoA as a substrate for acetyl-CoA carboxylase and subsequent reactions of fatty acid synthetase has a slightly beneficial effect on the overall rate of lipid synthesis in plants.
Cell Wall and Membrane-Associated Exo-β-d-Glucanases from Developing Maize Seedlings
Authors: Kim Jong-Bum , Olek Anna T. , Carpita Nicholas C.
Published: July 2002

A β-d-glucan exohydrolase was purified from the cell walls of developing maize (Zea mays L.) shoots. The cell wall enzyme preferentially hydrolyzes the non-reducing terminal glucosyl residue from (1→3)-β-d-glucans, but also hydrolyzes (1→2)-, (1→6)-, and (1→4)-β-d-glucosyl units in decreasing order of activity. Polyclonal antisera raised against the purified exo-β-d-glucanase (ExGase) were used to select partial-length cDNA clones, and the complete sequence of 622 amino acid residues was deduced from the nucleotide sequences of the cDNA and a full-length genomic clone. Northern gel-blot analysis revealed what appeared to be a single transcript, but three distinct polypeptides were detected in immunogel-blot analyses of the ExGases extracted from growing coleoptiles. Two polypeptides appear in the cell wall, where one polypeptide is constitutive, and the second appears at the time of the maximum rate of elongation and reaches peak activity after elongation has ceased. The appearance of the second polypeptide coincides with the disappearance of the mixed-linkage (1→3),(1→4)-β-d-glucan, whose accumulation is associated with cell elongation in grasses. The third polypeptide of the ExGase is an extrinsic protein associated with the exterior surface of the plasma membrane. Although the activity of the membrane-associated ExGase is highest against (1→3)-β-d-glucans, the activity against (1→4)-β-d-glucan linkages is severely attenuated and, therefore, the enzyme is unlikely to be involved with turnover of the (1→3),(1→4)-β-d-glucan. We propose three potential functions for this novel ExGase at the membrane-wall interface.
The Role of Vacuolar Malate-Transport Capacity in Crassulacean Acid Metabolism and Nitrate Nutrition. Higher Malate-Transport Capacity in Ice Plant after Crassulacean Acid Metabolism-Induction and in Tobacco under Nitrate Nutrition
Authors: Lüttge Ulrich , Pfeifer Tanja , Fischer-Schliebs Elke , Ratajczak Rafael
Published: July 2002

Anion uptake by isolated tonoplast vesicles was recorded indirectly via increased H+-transport by H+-pumping of the V-ATPase due to dissipation of the electrical component of the electrochemical proton gradient, ΔμH+, across the membrane. ATP hydrolysis by the V-ATPase was measured simultaneously after the Palmgren test. Normalizing for ATP-hydrolysis and effects of chloride, which was added to the assays as a stimulating effector of the V-ATPase, a parameter, Jmal  rel, of apparent ATP-dependent malate-stimulated H+-transport was worked out as an indirect measure of malate transport capacity. This allowed comparison of various species and physiological conditions. Jmal  rel was high in the obligate crassulacean acid metabolism (CAM) species Kalanchoëdaigremontiana Hamet et Perrier, it increased substantially after CAM induction in ice plant (Mesembryanthemum crystallinum), and it was positively correlated with NO3  − nutrition in tobacco (Nicotiana tabacum). For tobacco this was confirmed by measurements of malate transport energized via the V-PPase. In ice plant a new polypeptide of 32-kD apparent molecular mass appeared, and a 33-kD polypeptide showed higher levels after CAM induction under conditions of higher Jmal  rel. It is concluded that tonoplast malate transport capacity plays an important role in physiological regulation in CAM and NO3  −nutrition and that a putative malate transporter must be within the 32- to 33-kD polypeptide fraction of tonoplast proteins.
Knowledge management: strategy or software?
Authors: Beckett Alan J. , Wainwright Charles E.R. , Bance David
Published: July 2002

Knowledge management is a rapidly growing, and rapidly changing discipline. While the link between knowledge assets and competitive advantage has been accepted for some time, it is not obvious how this translates into the techniques and software tools that are labelled as knowledge management processes. This article details the strategic requirements linking the conceptual “mission” of knowledge management with the processes that serve it.
The acceptability of low fat sausages
Authors: Homer Dawn B. , Matthews Kim R. , Warkup Chris C.
Published: July 2002

Sausages from three major retail outlets producing their own label pork and reduced fat sausages were sampled over a period of four weeks. A branded product was also purchased from the stores. A trained sensory panel evaluated the sausages and found that, although the overall acceptability differed between retailers, one of the low fat products matched the equivalent standard product in terms of acceptability. The overall acceptability of the branded product was within the range of the own label standard products but below the most acceptable low fat product. It was concluded that, whilst the successful production of low fat sausages is possible, a wider range would be encouraged by the adoption of modified compositional standards.
Cutting the cord: student‐led discussion groups in higher education
Authors: Kremer John , McGuinness Carol
Published: July 2002

As the world of higher education has become increasingly sensitive to employers’ needs so attention has focused on the development of skills and competences which will equip graduates to function effectively in the labour market. High on the list of graduates’ desired qualities are first, the ability to work in a team and second, the capacity for independent thought and action. At the same time, there has been a growing recognition that traditional methods of teaching (primarily tutorials and lectures) may be serving to perpetuate the opposite, namely dependency and passivity. With these issues in mind, the article outlines the experience of using leaderless group discussions and associated peer assessment as an integral part of an undergraduate degree programme. The practicalities of running the groups, the lessons which have been learnt over time, and the benefits for student learning are also discussed.
Issues in training lecturers to exploit the Internet as a teaching resource
Authors: Fayter Debra
Published: July 2002

This paper outlines the rationale behind the development of a course aimed at university lecturers wishing to use the Internet for teaching and learning. It evaluates some of the potential benefits of using the Internet and assesses lecturers’ concerns about exploiting this teaching resource. It covers the design and development of the course. Finally, it considers some important points lecturers should bear in mind before embarking on using the Internet for teaching and learning.
Effects of national culture and organizational types of workers on the job‐related orientations of Japanese, US and Australian employees
Authors: Yamaguchi Ikushi
Published: July 2002

This study explores whether a nation‐culture factor (national culture) or a worker‐type factor (organizational types of workers) has more powerful effects on various job‐related orientations of Japanese, US and Australian employees. Job‐related orientations were categorized into the following three: job‐performance orientation, human‐relation orientation, and safety‐maintenance orientation. A total of 212 Japanese, 187 American and 147 Australian workers participated in this research. The subjects were grouped into five different organizational types of workers. The cultures‐by‐types interaction failed to achieve significance on the combined dependent variables. The cultures (nation‐culture) variable indicated significant relationships with human‐relation orientation and safety‐maintenance orientation, and the types (worker‐type) variable showed an indication of significant relationships with job‐performance orientation.
Neural networks: friends or foes?
Authors: Roberts Stephen J. , Penny Will
Published: July 2002

There has been enormous interest over the past decade in the use of artificial neural networks (ANNs) for data processing applications. By and large, this interest has been well‐founded. ANNs, however, offer no panacea to the data analyst. They are as prone to misuse as any other method and the details of their functioning are often clouded in mystique. This has made a firm understanding of their functioning difficult. Presents a brief introduction to the most widely applied class of ANN, the feed‐forward network. Gives an overview of its functioning for both classification and regression problems.
The cultural context of learning in international joint ventures
Authors: Liu Shimin , Vince Russ
Published: July 2002

Currently, learning in international joint ventures between developing and developed countries tends to be viewed as a one‐way process, with Western partners assuming superiority in both technology and management. Learning is often dominated by the rational drive to achieve organisational effectiveness without sufficient attention to cultural differences, which has created problems of mutual understanding. In this paper we examine learning processes in Chinese‐Western joint ventures as well as the cultural context where learning is taking place. We argue that improved management of joint ventures lies in the process of collective learning of joint venture partners. To achieve this, it is important for partners from diverse cultures and socio‐economic backgrounds to understand the different modes of managing and organising. We illustrate this with examples from our study of Chinese‐Western joint ventures.
Efficiency of refinement procedures for the p‐version of the adaptive finite element method
Authors: Papadrakakis M. , Babilis G. , Braouzi P.
Published: July 2002

Presents an efficiency study of different refinement procedures for the p‐version of the adaptive finite element method in two‐dimensional elasticity problems. The refinement strategy, based on the estimated error in energy norm, attempts an optimal distribution of the nodeless degrees of freedom associated with the basic approximation parameter of the order p of the hierarchical shape functions. This procedure is combined with appropriate matrix‐handling techniques and equation solvers in order to achieve a solution of a given accuracy with the minimum computational resources in terms of computing time and storage. To this extent, convergence studies are performed with constant and variable adaptivity indices, with error estimators based on global and elemental approaches and with domain decomposition matrix‐handling techniques and the preconditioned conjugate gradient solver.
Self‐designing structures: a practical approach
Authors: Christie W.C. , Bettess P. , Bull J.W.
Published: July 2002

Demonstrates the simple but effective application of a standard finite element program (PAFEC), and the associated geometric modelling code (PIGS), to the improvement of the design of an engineering component. The technique adopted involves augmenting material around zones of high stress and removing material in zones of low stress. This evolutionary procedure is related to the behaviour of bones in animals. The essentially two‐step procedure involves; finite element analysis of the preliminary component design using PAFEC; and, definition of a new geometry using PIGS, with selected stress contours giving an indication of the new shape. The technique, which proceeds iteratively, was first tested successfully on some classical academic optimisation problems. Its subsequent application to the industrial problem of a twin chamber pressurised extruded aluminium section, the primary component of an air drying system, resulted in material savings of up to 50 per cent and an associated drop in the maximum von Mises stress of 45 per cent. While this method does not determine the optimal structural form, it does generate substantial improvements in terms of material usage and reduced maximum stresses. It has the advantage that it can be used by any competent engineer with a working knowledge of the strength of materials, finite elements and structural form.
On the finite element analysis of inverse problems in fracture mechanics
Authors: Gadala Mohamed S. , McCullough Andrew D.B.
Published: July 2002

This paper presents a numerical study of inverse parameter identification problems in fracture mechanics. Inverse methodology is applied to the detection of subsurface cracks and to the study of propagating cracks. The procedure for detecting subsurface cracks combines the finite element method with a sequential quadratic programming algorithm to solve for the unknown geometric parameters associated with the internal flaw. The procedure utilizes finite element substructuring capabilities in order to minimize the processing and solution time for practical problems. The finite element method and non‐linear optimization are also used in determining the direction a crack will propagate in a heterogeneous planar domain. This procedure involves determining the direction that produces the maximum strain energy release for a given increment of crack growth. The procedure is applied to several numerical examples. The results of these numerical studies coincide with theoretical predictions and experimentally observed crack behavior.
Ten pints of Beer
Authors: Discussion
Published: July 2002

Details a discussion with Stafford Beer about the rationale of his cybernetic books published in the twentieth century (1959‐94). Includes a dialogue concerning his contributed works: Cybernetics and Management; Decision and Control; Management Science; Designing Freedom; Platform for Change; The Heart of Enterprise; Diagnosing the System for Organisations; and Beyond Dispute. Concludes with a perspective of some of his important early work and some unpublished contributions which have been collected into one book.
Buck raising in a small academic library: endowed book funds are an answer
Authors: Park Leland M.
Published: July 2002

Fund‐raising has become a more important part of the job of academic library directors. Small college libraries with small staffs must devise methods to raise funds, which are not burdensome for any one staff member. Endowed book funds are described here as such a vehicle for fund‐raising. The case described, now 25 years in place, has raised an endowment of over $6 million.
Post‐secondary educational leadership: preparing for the brave new world
Authors: Bond Richard , Boak Terry
Published: July 2002

Identifies a number of recent shifts in issues affecting education and examines the impact on leadership in education with particular reference to the Canadian context. Discusses implications for changes in leaders′ behaviours within the context of social and leadership theories. Presents some proposals which facilitate appropriate controls in educational leadership, but at the same time are supportive of increasing democratization. These do not represent an abrogation of administrative responsibilities, but emphasize the need for new views of the multiple roles of leaders in education at a time when international similarities are being identified.
Incorporating action research in school senior management training
Authors: Cardno Carol , Piggot‐Irvine Eileen
Published: July 2002

Outlines how an action research approach can be used for management training and education. The emphasis on developing competence in problem‐solving processes, using action research, is supported by the literature and this is illustrated by several examples of institutional projects and award‐bearing programmes. Details how the authors’ interpretation of action research, in the school management training context, can both challenge and develop educational leaders.
Japan’s administrative counselling – Maintaining public sector relevance?
Authors: Christensen Mark J.
Published: July 2002

Administrative counselling (AC) is a unique feature of Japan’s public sector. Comparable to a decentralised “shop front” ombudsman function, AC may serve to lift public confidence in administrative actions. This paper analyses AC as a contributor to program evaluation at a time when Japan’s public sector is in crisis and probably at a turning point in its history. A central question is whether AC can help the Japanese public sector to respond to increasing criticism of its performance and structures. AC deals with a large number of cases annually and so holds the potential to restore public confidence in the public sector. Aggregation of the patterns of complaint behind the AC cases can also be an effective diagnostic tool for the direction of program evaluation resources. The voluntary nature of AC and its reliance on the efforts of citizens of social standing may mean that it is not capable of implementation outside of Japan. While implementation of AC in non‐Japanese public sectors would require significant cultural shift it is nevertheless worthy of further analysis.
A simple finite element model for cloth drape simulation
Authors: Ascough J. , Bez H.E. , Bricis A.M.
Published: July 2002

Uses Newmark’s method to carry out a time‐stepping finite element analysis to predict the behaviour of a cloth garment as it falls from an initial horizontal position to a final position draped around a human body form. Bases the finite element model on a simple beam element, in order to minimize the computational time. Accounts for large displacement behaviour by including the element geometric stiffness. Bases the body form on anthropomorphic data produced by a shadow scanner. Enlists a novel scheme to model the contact between the cloth and the underlying body form. Uses the finite element model to provide data for an animated display and finds that it produces sufficiently realistic results for the garment designer’s purposes.
Vibrations of a crank‐shaft in a sewing machine induced by a zigzag mechanism
Authors: Zajaczkowski Jerzy
Published: July 2002

Torsional vibrations of a shaft induced by a zigzag mechanism in a sewing machine with an oscillatory hook are studied in this paper. The dynamic equations of the motion are derived using the principle of virtual work. The discrete forms of the functions relating the motion of machine elements are found using Newton‐Brent method. They are replaced locally by the continuous ones using Lagrange formula. The limit cycle trajectory is found by direct numerical integration and it is illustrated graphically. The presented mathematical model of the zigzag sewing machine makes it possible to choose the proper parameters of the machine at the preliminary state of design.
What constitutes high quality teaching and learning and how to assure it
Authors: Martens Erika , Prosser Michael
Published: July 2002

The evaluation and continuous improvement of the quality of teaching and learning in higher education is an issue of sustained concern. While most universities are implementing systems of quality assurance, there is substantial variation in the principles underlying these systems. La Trobe University has developed and implemented a university‐wide system of quality assurance that ensures that each subject is systematically reviewed and enhanced by those teaching in the subject. While it incorporates compulsory student evaluation of teaching of each subject the result of this student evaluation is not the focus of the quality assurance system. The focus is on ensuring that those teaching the subject, reflect on and make recommendations for further improvement of the subject. Outlines the quality assurance system, the principles on which it is based and describes and analyses the processes engaged in during its development.
Information security management and modelling
Authors: Kwok Lam‐for , Longley Dennis
Published: July 2002

Information security management has been placed on a firmer footing with the publication of standards by national bodies. These standards provide an opportunity for security managers to gain senior management recognition of the importance of procedures and mechanisms to enhance information security. They may also place demands on security managers to provide convincing demonstration of conformance to the standards. The risk data repository (RDR) computer model described in this paper was developed to manage organisational information security data and facilitate risk analysis studies. The RDR provides a form of computer documentation that can assist the security officer to maintain a continuous record of the organisational information security scenario and facilitate system security development, business continuity planning and standards conformance audits.
The First World Congress on the Management of Electronic Commerce: review and commentary
Authors: Bontis Nick , De Castro Akemi
Published: July 2002

Summarizes some of the key findings of academic papers presented at the First World Congress on the Management of Electronic Commerce, which took place in January, 2000, in Hamilton, Ontario, Canada, sponsored by McMaster University. The conference was attended by 243 delegates from more than 25 countries. Outlines two meta‐management issues including: the importance of taking a strategic approach to Internet ventures as well as considering infrastructure design during implementation. Several of the papers presented fell into three broad functional categories including operations, human resources and marketing. Finally, a summary of internationalization and education implications is discussed.
Spectral analysis of real estate and financial assets markets
Authors: Wilson Patrick , Okunev John
Published: July 2002

Understanding cyclical activity is an important component of efficient portfolio management. Property appraisal models that do not explicitly take into account cyclical fluctuations may produce unrealistic valuation estimates resulting in property assets being incorrectly added to or removed from the general investment portfolio. In this paper we use conventional spectral analysis techniques to examine property and financial assets for evidence of cycles and co‐cycles. One finding is that the very pronounced cyclical patterns that appear in direct real estate markets and the economy as a whole are very much less obvious once they have filtered through to securitised property markets and financial assets markets.
A novel target recognition revealed by calmodulin in complex with the basic helix–loop–helix transcription factor SEF2‐1/E2‐2
Authors: Larsson Göran , Schleucher Jürgen , Onions Jacqueline , Hermann Stefan , Grundström Thoman , Wijmenga Sybren S.
Published: July 2002

Calmodulin is the predominant intracellular receptor for Ca2+signals, mediating the regulation of numerous cellular processes. It can inhibit the DNA binding of basic helix–loop–helix transcription factors by a direct interaction of a novel type. To structurally characterize this novel calmodulin‐target interaction, we decided to study the complex of calmodulin with a dimeric peptide corresponding to the DNA‐binding domains of the dimeric basic helix–loop–helix transcription factor SEF2‐1 (SEF2‐1mp) using NMR. Here, we report that the stoichiometry of the calmodulin:SEF2‐1mp complex is one dimeric peptide binding two calmodulin molecules. We also report the 1H, 13C, and 15N resonance assignments and the secondary structure of calmodulin in this for NMR large (∼38 kD) complex, as well as the 1H assignments and secondary structure of SEF2‐1mp. In addition, we determined the amide proton exchange rates of calmodulin and measured intermolecular calmodulin:SEF2‐1mp and calmodulin:calmodulin NOE contacts. The isotope‐filtered experiments show a large number of SEF2‐1mp to calmodulin NOE contacts indicating that a tight complex is formed, which is confirmed by an intermolecular calmodulin:calmodulin NOE contact. The secondary structure and amide proton exchange data show that the binding does not occur via the classical wraparound binding mode. Instead, the data indicate that calmodulin interacts with SEF2‐1mp in a more open conformation, although the hydrophobic surfaces of the N‐ and C‐terminal domains still form the main interaction sites. Interactions involving charged residues are also identified in agreement with the known relatively high sensitivity of the binding to ionic strength. Finally, the peptide does not form an α‐helix as in the classical wraparound binding mode.
Identification of four proteins from the small subunit of the mammalian mitochondrial ribosome using a proteomics approach
Authors: Koc Emine Cavdar , Burkhart William , Blackburn Kevin , Koc Hasan , Moseley Arthur , Spremulli Linda L.
Published: July 2002

Proteins in the small subunit of the mammalian mitochondrial ribosome were separated by two‐dimensional polyacrylamide gel electrophoresis. Four individual proteins were subjected to in‐gel Endoprotease Lys‐C digestion. The sequences of selected proteolytic peptides were obtained by electrospray tandem mass spectrometry. Peptide sequences obtained from in‐gel digestion of individual spots were used to screen human, mouse, and rat expressed sequence tag databases, and complete consensus cDNAs for these species were deduced in silico. The corresponding protein sequences were characterized by comparison to known ribosomal proteins in protein databases. Four different classes of mammalian mitochondrial small subunit ribosomal proteins were identified. Only two of these proteins have significant sequence similarities to ribosomal proteins from prokaryotes. These proteins are homologs to Escherichia coli S9 and S5 proteins. The presence of these newly identified mitochondrial ribosomal proteins are also investigated in the Drosophila melanogaster, Caenorhabditis elegans, and in the genomes of several fungi.
Cellular mechanisms of nitric oxide‐induced relaxation of corporeal smooth muscle in the guinea‐pig
Authors: Hashitani Hikaru , Fukuta Hiroyasu , Dickens Emma J. , Suzuki Hikaru
Published: July 2002

The cellular mechanism of nitric oxide (NO)‐induced relaxation in corporeal smooth muscle (CSM) of the guinea‐pig was investigated. Changes in the intracellular concentration of calcium ions ([Ca2+]i), membrane potential and isometric tension were measured. CSM cells exhibited spontaneous depolarizations and transient increases in [Ca2+]i (Ca2+ transients) which were accompanied by contractions. This spontaneous activity was abolished by nifedipine (10 μm). NO released by 3‐morpholino‐sydnonimine (SIN‐1, 10 μm) hyperpolarized the membrane and prevented the generation of spontaneous depolarizations. SIN‐1 also abolished Ca2+ transients and associated contractions. These effects of SIN‐1 were blocked by 1H‐[1,2,4]oxadiazole[4,3‐a]quinoxalin‐1‐one (ODQ, 10 μm), an inhibitor of guanylate cyclase. Noradrenaline (NA, 1 μm) increased [Ca2+]i to levels similar to those produced by high potassium‐containing solution (high K+ solution, [K+]o= 40 mm), however, NA‐induced contractions were three times greater in amplitude than those induced by high K+ solution. In NA precontracted preparations, SIN‐1 inhibited 80 % of the contraction and decreased [Ca2+]i by 20 %. In contrast, nifedipine reduced [Ca2+]i by 80 %, while the level of contraction was decreased by only 20 %. SIN‐1‐induced reduction in [Ca2+]i but not the tension effect, was abolished by pretreatment with cyclopiazonic acid (CPA, 10 μm). In high K+ precontracted preparations, SIN‐1 inhibited 80 % of the contraction and reduced [Ca2+]i by 20 %. Nifedipine, however, largely abolished increases in both [Ca2+]i and tension under these circumstances. These results suggest that decreasing the sensitivity of contractile proteins to Ca2+ is probably the key mechanism of NO‐induced relaxation in CSM of the guinea‐pig.
Depression of hypoxic arousal response in adolescent mice following antenatal vasoactive intestinal polypeptide blockade
Authors: Cohen Gary , Gressens Pierre , Gallego Jorge , Gaultier Claude
Published: July 2002

Late‐gestation blockade of vasoactive intestinal polypeptide (VIP) activity in pregnant mice produces discrete morphological abnormalities in the somatosensory cortex of offspring. We investigated the functional implications of this lesion on the behavioural arousal response to moderate hypoxia. Pregnant mice received twice‐daily injections of 200 μl saline (control), or saline + 50 μg VIP antagonist (anti‐VIP) on embryonic days 17 and 18. Offspring were studied unrestrained at 6–7 weeks after birth, in a bias‐flow whole‐body plethysmograph during behavioural quiet sleep. Arousal was defined by movement (MVT) lasting >1 s. Hypoxic ventilatory (HVR) and arousal responses were measured during a 5 min exposure to 10 % O2‐3 % CO2 (hypoxia); peripheral chemoreflex drive was estimated by transient hyperoxia administered at rest and end‐hypoxia (Dejours‐type test). MVTs increased in all mice during hypoxia, but in anti‐VIP mice: (a) MVT onset was delayed (174 ± 90 vs. 108 ± 59 s from the start of hypoxia, anti‐VIP vs. control; P= 0.008); and (b) MVTs were less frequent, and total MVT time in hypoxia was less (8 ± 7 vs. 15 ± 9 %; P= 0.03). The HVR, and peripheral drive at rest and end‐hypoxia were comparable in control and anti‐VIP mice. In conclusion, a significant arousal deficit was evident in anti‐VIP mice. This was not associated with obviously deranged peripheral or brainstem‐mediated responses to hypoxia during sleep. This may signal a general deficit in the way hypoxic distress is monitored and processed, and arousal initiated and sustained in these mice.
Performance of Pre-Swirl Rotating-Disc Systems
Authors: Karabay Hasan , Pilbrow Robert , Wilson Michael , Owen J. Michael
Published: July 2002

This paper summarizes and extends recent theoretical, computational, and experimental research into the fluid mechanics, thermodynamics, and heat transfer characteristics of the so-called cover-plate pre-swirl system. Experiments were carried out in a purpose-built rotating-disc rig, and the Reynolds-averaged Navier-Stokes equations were solved using two-dimensional (axisymmetric) and three-dimensional computational codes, both of which incorporated low-Reynolds-number k-ε turbulence models. The free-vortex flow, which occurs inside the rotating cavity between the disc and cover-plate, is controlled principally by the pre-swirl ratio, βp: this is the ratio of the tangential velocity of the air leaving the nozzles to that of the rotating disc. Computed values of the tangential velocity are in good agreement with measurements, and computed distributions of pressure are in close agreement with those predicted by a one-dimensional theoretical model. It is shown theoretically and computationally that there is a critical pre-swirl ratio, βp,crit, for which the frictional moment on the rotating discs is zero, and there is an optimal pre-swirl ratio, βp,opt, where the average Nusselt number is a minimum. Computations show that, for βp<βp,opt, the temperature of the blade-cooling air decreases as βp increases; for βp>βp,opt, whether the temperature of the cooling air increases or decreases as βp increases depends on the flow conditions and on the temperature difference between the disc and the air. Owing to the three-dimensional flow and heat transfer near the blade-cooling holes, and to unquantifiable uncertainties in the experimental measurements, there were significant differences between the computed and measured temperatures of the blade-cooling air. In the main, the three-dimensional computations produced smaller differences than the two-dimensional computations. [S0742-4795(00)01902-5]
An On-line Condition Monitoring and Diagnosis System for Feed Rolls in the Plate Mill
Authors: Jeng J. J. , Wei C. Y.
Published: July 2002

An on-line condition monitoring and diagnosis system for feed rolls was developed for providing early warnings of malfunctions so as to avoid great losses resulting from unexpected shutdown of the production line. This system measures the bearing vibration signals on-line and judges the feed roll condition automatically according to the diagnosis rules stored in the computer. These rules were established based on results of long-term vibration measurements and proved by many real cases to be very effective and reliable. The derivation of these diagnosis rules and the development of the on-line monitoring and diagnosis system based on these rules are depicted in this article.
Differential Geometrical Conditions of Hypoid Gears with Conjugate Tooth Surfaces
Authors: Ito Norio , Takahashi Koichi
Published: July 2002

Hypoid gears are one of the most general form of gearing, and a theoretical solution for them has been studied by many researchers. Many hypotheses and theorems about these gears have been proposed—some of them correct and many of them wrong. The tooth surfaces are parts of general curved surfaces and they must have principal directions and principal curvatures on every contact point. However, there has been no detailed research on the fundamental elements of the surface. This study develops necessary conditions for determining these curvatures and principal directions for conjugate gearing with a contact line by introducing the concept of geodesic torsions. [S1050-0472(00)00503-1]
Large Eddy Simulation of a Smooth Circular Cylinder Oscillating Normal to a Uniform Flow
Authors: Tutar Mustafa , Holdo̸ Arne E.
Published: July 2002

Results of a numerical evaluation of transitional flow around a circular cylinder forced to oscillate in a direction normal to a uniform flow are presented. The cylinder is considered to be a representative of a single riser exposed to a steady current. Numerical simulations were carried out using the LES method in 2-D and 3-D with a near-wall approach that was developed without using a “law of the wall” for a finite element code (FEM). The 3-D simulations were compared with the 2-D results and experimental data in order to assess the relative performance of the 3-D LES simulations. The results show that 3-D LES gives more realistic flow field predictions and can further remove overconservatism in the prediction of hydrodynamic force coefficients. [S0098-2202(00)01103-2]
Sheet Forming Analysis Based on Improved Contact Searching Algorithm and Simple Approach for Contact Force Evaluation
Authors: Li G. Y. , Tan M. J. , Liew K. M. , Zhong Z. H.
Published: July 2002

Explicit finite element procedures for the simulation of sheet-metal-forming processes are reviewed. Improved techniques for contact searching and contact force evaluation are then proposed and discussed. In the contact searching algorithm, a new contact territory definition is introduced and only node-to-segment contact pairs are defined, which makes the post-contact searching more efficient and easy to implement. For contact force evaluation, a novel approach is employed to make the simulation of sheet forming processes more accurate. The algorithms are implemented and examined via experiments.
Influence of Crossflow-Induced Swirl and Impingement on Heat Transfer in an Internal Coolant Passage of a Turbine Airfoil
Authors: Ekkad S. V. , Pamula G. , Acharya S.
Published: July 2002

Detailed heat transfer distributions are presented inside a two-pass coolant channel with crossflow-induced swirl and impingement. The impingement and passage crossflow are generated from one coolant passage to the adjoining coolant passage through a series of straight or angled holes along the dividing wall. The holes provide for the flow turning from one passage to another typically achieved in a conventional design by a 180-deg U-bend. The holes direct the flow laterally from one passage to another and generate different secondary flow patterns in the second pass. These secondary flows produce impingement and swirl and lead to higher heat transfer enhancement. Three different lateral hole configurations are tested for three Reynolds numbers (Re=10,000, 25,000, 50,000). The configurations were varied by angle of delivery and location on the divider wall. A transient liquid crystal technique is used to measure the detailed heat transfer coefficient distributions inside the passages. Results with the new crossflow feed system are compared with the results from the traditional 180-deg turn passage. Results show that the crossflow feed configurations produce significantly higher Nusselt numbers on the second pass walls without affecting the first pass heat transfer levels. The heat transfer enhancement is as high as seven to eight times greater than obtained in the second pass for a channel with a 180-deg turn. The increased measured pressure drop (rise in friction factor) caused by flow through the crossflow holes are compensated by the significant heat transfer enhancement obtained by the new configuration. [S0022-1481(00)03103-0]
A Simple Technique for Maximizing the Fundamental Frequency of Vibrating Structures
Authors: Ong J. H. , Lim G. H.
Published: July 2002

A general approach for finding the optimal support locations to maximize the fundamental natural frequency of vibrating structures is described in this paper. The key to the procedure is to place the necessary supports in such a way, so as to eliminate the lower modes from the original configuration. This is accomplished by placing supports along the nodal lines of the highest possible mode from the original configuration, so that all the other lower modes are eliminated by the introduction of new or extra supports to the structure. For two-dimensional analysis, the average driving point residues calculated along a nodal line is used as an indicator for finding the vicinity of the ideal support locations. [S1043-7398(00)00504-1]