bluuebunny/crossref_metadata_2025 huggingface dataset:
Managing in polychronic times
Authors: Lynne Persing D.
Published: July 2002

As competitive pressures mount, firms are attempting to do more with less – and far more quickly. They are downsizing, using teams, and pushing the time to market. These trends promote polychronic behavior in that they require additional variety in the tasks, activities, and roles that individuals must handle simultaneously. Although evidence suggests that creativity and polychronic preferences are positively related, demands for polychronic behavior appear to be defeating – and resisted – in creative venues such as R&D. This paper addresses this apparent disjunction by focusing on the definition of polychronicity, emphasizing the critical role of agency and the need to count as activities the not particularly visible workings of the mind. The paper proposes, in part, that among creative workers, individual creativity is more related to polychronicity than to monochronicity. Further, volition will play a moderating role in that the relationship between creative performance and either chronicity will be stronger the higher personal agency is in choosing tasks and schedules.
Mapping intellectual resources: insights from critical modernism
Authors: O’Regan Philip , O’Donnell David
Published: July 2002

A consensus is emerging that the key to competitive success is becoming the ability to create, leverage, maintain and develop specialised knowledge, competencies and intellectual resources. However, little is actually known about the creation, management, utilisation and valuation of such resources. Although a concept such as intellectual capital cannot be precisely defined, this should not prevent us from employing it in an era where the intangible is rapidly assuming economic, social and psychological supremacy over the tangible. Moving beyond objectivist and purely systems theoretic approaches, our point of departure in exploring this emergent dynamic, with implications for people management and accountancy, is the set of symmetric and reciprocal relations presupposed in Habermas’ concept of communicative action.
Training micro‐business owner‐managers: a challenge to current approaches
Authors: Greenbank Paul
Published: July 2002

Despite the importance of micro‐businesses to the UK economy, training has failed to recognise and take into account the way owner‐managers run such firms. These owner‐managers tend to combine informally absorbed information, heuristics and other short‐cut methods in a more intuitively‐based approach to decision making. Does not, however, advocate that more formalised and comprehensive forms of decision making should be adopted. Instead, suggests that intuitive methods of decision making may be the most appropriate for micro‐business owner‐managers. As such, training should attempt to reduce the types of bias that are inherent in more intuitive approaches to decision making.
The emergence of strategic human resource development
Authors: Garavan Thomas N. , Costine Pat , Heraty Noreen
Published: July 2002

Focuses on the emergence of human resource development. Traces the emergence of HRD in the training and development literature. Also examines the extent to which a strategic approach to training and development is practised in industry. Concludes by examining the implications of a move towards a more strategic approach to training and development.
Management cybernetics: manufacturing in China
Authors: Wu Jialei , Plenert Gerhard
Published: July 2002

Discusses the potential development for industrial activity in China, and considers that the rate of improvement depends greatly on the “opening” of the government’s policy. This, together with the introduction of advanced technology and facilities, should provide the manufacturing industry with very strong prospects for the future.
Studies on the properties of silicone resin films on mild steel
Authors: Chew K.W. , Yahaya A.H. , Arof A.K.
Published: July 2002

The physical properties of two types of silicone resin were examined. The resin was coated on mild steel panels and allowed to cure for one week. The resin‐coated panels were heated according to ASTM specification D 2485. The thermal stability of the resin coatings was examined by electrochemical impedance spectroscopy (EIS) technique and thermogravimetric analyses (TGA). The chemical resistance property of the resin coatings was also studied.
Teams in Schools:
Authors: Walker Allan
Published: July 2002

The development of teams is an increasingly popular approach to
participation and restructuring in schools. Moves towards team
approaches are driven by two metaphors. The first is the market metaphor
which calls on schools to become more flexible and adaptable. The second
is the collaboration metaphor which values participation, collegiality,
empowerment, shared leadership and professionalism at a school level.
Intertwined with both is a growing acceptance that student outcomes and
teaching and learning must drive school decisions and structures. For
teams to become a meaningful form of collaboration and not simply a
cosmetic adjustment to meet managerial ends, schools, and particularly
principals, need to rethink power relationships and the meaning of
leadership in schools. They need to reconsider current school structures
and cultures and how they can be changed or developed to accommodate
team approaches and shared power. Principals must be willing to break
down traditional processes and rebuild them to achieve congruence with
teams and teamwork.
Obstacles to successful implementation of strategic decisions: the British experience
Authors: Al‐Ghamdi Salem M.
Published: July 2002

This study replicates and extends Alexander’s study for the purpose of identifying the recurring implementation problems. One hundred questionnaires were mailed to business companies in the Bradford area (UK). Twenty‐seven questionnaires have been returned of which only 24 are usable. Six strategy implementation problems were experienced during implementation by over 70 per cent of the sample group. Anova results also show that firms experiencing high success in implementation have less problems compared to low success group. Communication, management support, and good information system are the key tools for smooth implementation processes.
Optimized garment pattern generation based on three‐dimensional anthropometric measurement
Authors: Jin Kang Tae , Min Kim Sung
Published: July 2002

An automatic garment pattern generation system has been developed for the three‐dimensional apparel CAD system. To substitute the garment fitting process, which requires lots of trial and error in the traditional pattern generation methods, we developed a new direct pattern generation method using body‐garment shape matching process. In this method, we first generated a body model using three‐dimensionally measured anthropometric data and transformed it to have a convex shape similar to that of a commonly used dummy model in garment design process. Then a typical garment model has been defined by measuring the surface information of a dummy model using stereoscopy and adjusting its shape considering the geometrical constraints of the underlying body model to obtain the optimum fit garment patterns. Finally, we developed a pattern flattening algorithm that flattens the three‐dimensionally adjusted garment model into two‐dimensional patterns considering the anisotropic properties of the fabric to be used.
Knowledge‐base construction of a garment manufacturing expert system
Authors: Kyu Park Chang , Hoon Lee Dae , Jin Kang Tae
Published: July 2002

Focuses on Korean garment manufacturing and the feasibility and benefits of introducing an expert system. Reviews previous literature on knowledge‐based system and describes in detail the stages followed in developing, constructing, testing, evaluating, integrating, implementing and maintaining the expert system. Concludes that an expert system could be used to solve various garment manufacturing problems and would contribute to garment quality improvement through a standardized apparel production process.
Vision and leadership of principals in Hong Kong
Authors: Sheung Chui Hong , Sharpe Fenton G. , McCormick John
Published: July 2002

Describes a study which investigated the relationship between the vision and five dimensions of leadership behaviour of principals in Hong Kong. A survey was carried out on 48 secondary schools involving 548 teachers. Half of the sample schools were in a pilot scheme of school‐based management, the school management initiative (SMI). Factor analysis and multiple regression were used to analyse the data. The results suggested that five dimensions of leadership behaviour were all significantly related to the vision of principals for both types of schools. Whether the school was participating in the SMI or not also had a significant effect on the relationship between the vision of principals and three dimensions of leadership behaviour. Contrary to the expectations of the SMI and the suggestions by some researchers that teachers need to be particularly empowered in schools undergoing reforms, the findings of this study demonstrated that for principals with average and below average scores on vision, the degree of empowerment perceived by teachers in schools under the SMI was lower than for schools not under the reform. However, principals with high vision in schools under the reform had the highest scores in all five dimensions of leadership behaviour. The SMI may provide opportunities for leaders with vision to bring about a better environment for school improvement. These results provide important insights for those responsible for the implementation and evaluation of the SMI in Hong Kong, and perhaps for other systems devolving decision‐making power to more self‐managing schools.
Method effects on theory testing: the case of organizational coupling in education
Authors: Yair Gad
Published: July 2002

Shows how methodological choices are not theoretically neutral. Draws attention to ways in which different analyses of the same data may affect inferences about teachers’ policy coupling in school systems. In this case study of the Jerusalem school system the authors used three statistical procedures to assess teachers’ perceived policy alignment among three organizational levels (teachers; schools; and the Israel Ministry of Education (IMOE)). Analyses using descriptive statistics show that the perceived policies at the three levels are similar, thus giving some support to the theory of tight coupling. Smallest Space Analysis shows that there are close connections between the teachers’ own policies and those they impute to schools, but not those they impute to the IMOE. These findings support a moderate view of organizational coupling. Finally, variance component analyses find almost no consensus in schools regarding policies. In contrast to the other approaches, these models support a loose coupling hypothesis. In overview, shows how methodological choices affect the support given to rival theoretical hypotheses. Suggests that theoretical looseness with regard to explicit falsification conditions is at the root of contrasting evidence about teacher coupling in school systems.
Determinants and prevalence of occupational stress among Zimbabwean school administrators
Authors: Nhundu Tichatonga J.
Published: July 2002

A survey of the literature will undoubtedly show that the last two decades have witnessed a proliferation of research studies on occupational stress among educational personnel, and that interest in this area has not abated. Unfortunately, little is known about occupational stress in many developing societies because a preponderance of these studies have been carried out in industrialized and developed societies where conditions may be dissimilar to those obtaining in developing societies. Therefore, the current study sought to contribute to a better understanding of occupational stress in teaching by investigating the sources, incidence and intensity of administrative stress among headteachers in Zimbabwe. The results of a survey of a sample of 95 headteachers showed that the sample experienced relatively high levels of administrative stress compared with previous findings. In addition, the study revealed several demographic characteristics and school variables which influenced the respondents’ perceptions of situations which cause stress. Finally, implications of the study were discussed in terms of policy, preparation of school administrators, school management and future research.
Privacy and security on the Internet: how to secure your personal information and company data
Authors: Attaran Mohsen , VanLaar Ilja
Published: July 2002

More and more people are logging on to the Internet. The increased use of the Internet and the World Wide Web for everyday activities is bringing new threats to personal privacy. Your activities, whether they are passive or active, in Cyberspace can give others a great deal of information about you. This paper gives an overview of where the risks lie, and how to minimize the risk to you and your work.
Australian academic use of the Internet
Authors: Applebee Andrelyn C. , Clayton Peter , Pascoe Celina
Published: July 2002

It is widely assumed ‐ and frequently asserted ‐ that university communication practices are being radically transformed by the introduction of electronic communication. Explores the introduction of Internet access in a single university, the University of Canberra, located in the capital city of Australia. The prime objective was to identify the frequency and type of use that academic staff were making of the Internet during 1995, with supplementary objectives being to record perceptions of users toward the Internet, and barriers to its effective use. The principal finding is not unexpected: academics were making very varied use of the Internet. Some staff were utilizing some facilities on a daily basis; others were yet to begin exploring this new communication medium. A particular surprise was that at the time of this survey the Internet was being used very little for teaching.
Benchmarking: a tool for Web site evaluation and improvement
Authors: Johnson Kelsey L. , Misic Mark M.
Published: July 2002

Although benchmarking has touched many areas of an organization, including information systems, very few examples are available on how this powerful methodology can be used to specifically address one of the fastest growing elements within information systems – the World Wide Web. This paper presents a case study on how benchmarking was used to determine how one organization’s Web site compared to Web sites of related schools and professional organizations. The results of the benchmarking study provided a measure of how our Web site compares to the sites of related organizations, ideas on how we may further enhance our site, and also a way to regularly evaluate our site.
Measuring vocational interests: a call for multi‐sample norms
Authors: Simons Roland , Goddard Richard , Patton Wendy
Published: July 2002

Increasing trends toward casualization of the workforce and job mobility have increased the need for delivery of targeted career counselling relevant to the specific needs of individuals but have not been matched by refinements to vocational interest instruments, which have largely remained focussed on student‐based norms. By investigating the interests and factor structure of the Vocational Interest Survey for Australia (VISA), this study has replicated earlier findings that the unemployed appear to respond with higher mean interest levels on the VISA in comparison to the instrument’s normative sample of secondary students. In comparison to an earlier study of unemployed white‐collar workers, the present study suggests that unemployed managers are able to discriminate between more dimensions of vocational interests than their non‐managerial counterparts. This observation is interpreted as support for a call to investigate the need for multi‐sample norming for vocational interest instruments.
Knowledge capabilities as the focus of organisational development and strategy
Authors: Dawson Ross
Published: July 2002

Knowledge organisations perform knowledge processes, using their primary resources of intellectual capital, and their key input of information. Their effectiveness in performing these processes depends on their knowledge capabilities. In most cases these capabilities must be highly dynamic in order to respond to the changing environment of the organisation and resulting evolution of the required core knowledge processes of the organisation. All organisational development must be centred around developing those dynamic knowledge capabilities on an ongoing basis. The strategic capabilities of an organisation depend on its ability to process rapidly changing information and perspectives on the organisation and its business environment, so these are in fact high‐order knowledge capabilities. The development of organisational knowledge capabilities can be addressed most completely by considering the four fields of individual technology, organisational technology, individual skills and behaviours, and organisational skills and behaviours.
Aborted property transactions: seller under‐compensation in the absence of legal recourse
Authors: Eng Ong Seow
Published: July 2002

Property purchasers who rescind on their contracts and forfeit the initial deposits are exercising their right to not proceed with the purchase. The deposit to purchase endows on the buyer an implicit call option that is valuable and the value exceeds the face value of the deposit. As such, real estate sellers and developers are not adequately compensated for the abortion risk, especially when there is no legal recourse for the sellers to seek specific performance and damages in the event of default. The historical value of this call is estimated by inferring a time‐varying volatility from Singapore residential price data over the last 20 years. The results show that real estate prices are more volatile in up markets than down markets, and that under‐compensation persists in both market conditions. This paper further highlights some measures to reduce the risk of aborted sales and the under‐compensation problem.
Solution structure and backbone dynamics of the DNA‐binding domain of mouse Sox‐5
Authors: Cary Peter D. , Read Christopher M. , Davis Ben , Driscoll Paul C. , Crane‐Robinson Colyn
Published: July 2002

The fold of the murine Sox‐5 (mSox‐5) HMG box in free solution has been determined by multidimensional NMR using 15N‐labeled protein and has been found to adopt the characteristic twisted L‐shape made up of two wings: the major wing comprising helix 1 (F10–F25) and helix 2 (N32–A43), the minor wing comprising helix 3 (P51–Y67) in weak antiparallel association with the N‐terminal extended segment. 15N relaxation measurements show considerable mobility (reduced order parameter, S2) in the minor wing that increases toward the amino and carboxy termini of the chain. The mobility of residues C‐terminal to Q62 is significantly greater than the equivalent residues of non‐sequence‐specific boxes, and these residues show a weaker association with the extended N‐terminal segment than in non‐sequence boxes. Comparison with previously determined structures of HMG boxes both in free solution and complexed with DNA shows close similarity in the packing of the hydrophobic cores and the relative disposition of the three helices. Only in hSRY/DNA does the arrangement of aromatic sidechains differ significantly from that of mSox‐5, and only in rHMG1 box 1 bound to cisplatinated DNA does helix 1 have no kink. Helix 3 in mSox‐5 is terminated by P68, a conserved residue in DNA sequence‐specific HMG boxes, which results in the chain turning through ∼90°.
Crystal structure of an archaeal DNA sliding clamp: Proliferating cell nuclear antigen from Pyrococcus furiosus
Authors: Matsumiya Shigeki , Ishino Yoshizumi , Morikawa Kosuke
Published: July 2002

The proliferating cell nuclear antigen (PCNA) is now recognized as one of the key proteins in DNA metabolic events because of its direct interactions with many proteins involved in important cellular processes. We have determined the crystal structure of PCNA from a hyperthermophilic archaeon, Pyrococcus furiosus (PfuPCNA), at 2.1 Å resolution. PfuPCNA forms a toroidal, ring‐shaped structure consisting of homotrimeric molecules, which is also observed in the PCNA crystals from human and yeast. The overall structure of PfuPCNA is highly conserved with other PCNA proteins, as well as with the bacterial β clamp and the bacteriophage gp45. This result shows that the three‐dimensional structure of the sliding clamp is conserved in the three domains of life. PfuPCNA has two remarkable features compared with the human and yeast PCNA molecules: it has more ion pairs and fewer intermolecular main chain hydrogen bonds. The former may contribute to the thermal stability of PfuPCNA, and the latter may be the cause of the stimulatory effect of PfuPCNA on the DNA synthesizing activity of P. furiosus DNA polymerases in the absence of the clamp loader replication factor C in vitro.
Open‐and‐shut cases in coiled‐coil assembly: α‐sheets and α‐cylinders
Authors: Walshaw John , Woolfson Derek N.
Published: July 2002

The coiled coil is a ubiquitous protein‐folding motif. It generally is accepted that coiled coils are characterized by sequence patterns known as heptad repeats. Such patterns direct the formation and assembly of amphipathic α‐helices, the hydrophobic faces of which interface in a specific manner first proposed by Crick and termed “knobs‐into‐holes packing”. We developed software, socket, to recognize this packing in protein structures. As expected, in a trawl of the protein data bank, we found examples of canonical coiled coils with a single contiguous heptad repeat. In addition, we identified structures with multiple, overlapping heptad repeats. This observation extends Crick's original postulate: Multiple, offset heptad repeats help explain assemblies with more than two helices. Indeed, we have found that the sequence offset of the multiple heptad repeats is related to the coiled‐coil oligomer state. Here we focus on one particular sequence motif in which two heptad repeats are offset by two residues. This offset sets up two hydrophobic faces separated by ≈150°–160° around the α‐helix. In turn, two different combinations of these faces are possible. Either similar or opposite faces can interface, which leads to open or closed multihelix assemblies. Accordingly, we refer to these two forms as α‐sheets and α‐cylinders. We illustrate these structures with our own predictions and by reference to natural variants on these designs that have recently come to light.
Ligand binding to the inhibitory and stimulatory GTP cyclohydrolase I/GTP cyclohydrolase I feedback regulatory protein complexes
Authors: Yoneyama Toshie , Hatakeyama Kazuyuki
Published: July 2002

GTP cyclohydrolase I feedback regulatory protein (GFRP) mediates feedback inhibition of GTP cyclohydrolase I activity by 6R‐l‐erythro‐5,6,7,8‐tetrahydrobiopterin (BH4), which is an essential cofactor for key enzymes producing catecholamines, serotonin, and nitric oxide as well as phenylalanine hydroxylase. GFRP also mediates feed‐forward stimulation of GTP cyclohydrolase I activity by phenylalanine at subsaturating GTP levels. These ligands, BH4 and phenylalanine, induce complex formation between one molecule of GTP cyclohydrolase I and two molecules of GFRP. Here, we report the analysis of ligand binding using the gel filtration method of Hummel and Dreyer. BH4 binds to the GTP cyclohydrolase I/GFRP complex with a Kd of 4 μM, and phenylalanine binds to the protein complex with a Kd of 94 μM. The binding of BH4 is enhanced by dGTP. The binding stoichiometrics of BH4 and phenylalanine were estimated to be 10 molecules of each per protein complex, in other words, one molecule per subunit of protein, because GTP cyclohydrolase I is a decamer and GFRP is a pentamer. These findings were corroborated by data from equilibrium dialysis experiments. Regarding ligand binding to free proteins, BH4 binds weakly to GTP cyclohydrolase I but not to GFRP, and phenylalanine binds weakly to GFRP but not to GTP cyclohydrolase I. These results suggest that the overall structure of the protein complex contributes to binding of BH4 and phenylalanine but also that each binding site of BH4 and phenylalanine may be primarily composed of residues of GTP cyclohydrolase I and GFRP, respectively.
Observation of the closing of individual hydrogen bonds during TFE–induced helix formation in a peptide
Authors: Jaravine Victor A. , Alexandrescu Andrei T. , Grzesiek Stephan
Published: July 2002

Helix formation of an S‐peptide analog, comprising the first 20 residues of Ribonuclease A and two additional N‐terminal residues, was studied by measuring hydrogen bond (H‐bond) h3JNC′ scalar couplings as a function of 2,2,2‐trifluoroethanol (TFE) concentration. The h3JNC′ couplings give direct evidence for the closing of individual backbone N‐H•••O = C H‐bonds during the TFE‐induced formation of secondary structure. Whereas no h3JNC′ correlations could be detected without TFE, α‐helical (i,i +4) H‐bond correlations were observed for the amides of residues A5 to M15 in the presence of TFE. The analysis of individual coupling constants indicates that α‐helix formation starts at the center of the S‐peptide around residue E11 and proceeds gradually from there to both peptide ends as the TFE concentration is increased. At 60% to 90% TFE, well‐formed α‐helical H‐bonds were observed for the amides hydrogens of residues K9 to Q13, whereas H‐bonds of residues T5 to A8, H14, and M15 are affected by fraying. No intramolecular backbone H‐bonds are present at and beyond the putative helix stop signal D16. As the h3JNC′ constants represent ensemble averages and the dependence of h3JNC′ on H‐bond lengths is very steep, the size of the individual h3JNC′ coupling constants can be used as a measure for the population of a closed H‐bond. These individual populations are in agreement with results derived from the Lifson‐Roig theory for coil‐to‐helix transitions. The present work shows that the closing of individual H‐bonds during TFE‐induced helix formation can be monitored by changes in the size of H‐bond scalar couplings.
Effects of resistance and stretching training programmes on the viscoelastic properties of human tendon structures in vivo
Authors: Kubo Keitaro , Kanehisa Hiroaki , Fukunaga Tetsuo
Published: July 2002

The present study examined whether resistance and stretching training programmes altered the viscoelastic properties of human tendon structures in vivo. Eight subjects completed 8 weeks (4 days per week) of resistance training which consisted of unilateral plantar flexion at 70 % of one repetition maximum with 10 repetitions per set (5 sets per day). They performed resistance training (RT) on one side and resistance training and static stretching training (RST; 10 min per day, 7 days per week) on the other side. Before and after training, the elongation of the tendon structures in the medial gastrocnemius muscle was directly measured using ultrasonography, while the subjects performed ramp isometric plantar flexion up to the voluntary maximum, followed by a ramp relaxation. The relationship between estimated muscle force (Fm) and tendon elongation (L) was fitted to a linear regression, the slope of which was defined as stiffness. The hysteresis was calculated as the ratio of the area within the Fm‐L loop to the area beneath the load portion of the curve. The stiffness increased significantly by 18.8 ± 10.4 % for RT and 15.3 ± 9.3 % for RST. There was no significant difference in the relative increase of stiffness between RT and RST. The hysteresis, on the other hand, decreased 17 ± 20 % for RST, but was unchanged for RT. These results suggested that the resistance training increased the stiffness of tendon structures as well as muscle strength and size, and the stretching training affected the viscosity of tendon structures but not the elasticity.
Effects of phosphocreatine on SR Ca2+ regulation in isolated saponin‐permeabilized rat cardiac myocytes
Authors: Yang Zhaokang , Steele Derek S.
Published: July 2002

The effects of phosphocreatine (PCr) on sarcoplasmic reticulum (SR) Ca2+ regulation were investigated in saponin‐permeabilized rat ventricular myocytes. Cells were perfused continuously with weakly Ca2+‐buffered solutions approximating to the intracellular milieu. Ca2+ release from the SR was detected using Fura‐2 or Fluo‐3. Withdrawal of PCr reduced the frequency of spontaneous Ca2+ release by 12.8 ± 3.4 % (n= 9) and the amplitude of the spontaneous Ca2+ transient by 17.4 ± 3.1 % (n= 9). Stepwise reductions in [PCr] progressively increased the time for the spontaneous Ca2+ transient to rise from 25 to 100 % of the maximum value (TP75) and to fall by 75 % of the peak level (DT75). Following complete PCr withdrawal, the TP75 and the DT75 were 147.1 ± 13.2 and 174.8 ± 23.2 % of the control values, respectively. Experiments involving confocal microscopy showed that PCr withdrawal decreased the propagation velocity of spontaneous Ca2+ waves. PCr withdrawal also reduced the frequency and amplitude, but increased the duration of spontaneous Ca2+ sparks. Rapid application of 20 mm caffeine was used to assess the SR Ca2+ content at the point of spontaneous Ca2+ release. In the absence of PCr, the amplitude of the caffeine‐induced Ca2+ transient was 18.4 ± 2.7 % (n= 9) lower than in the presence of 10 mm PCr. This suggests that PCr withdrawal reduces the maximum SR Ca2+ content that can be sustained before spontaneous Ca2+ release occurs. These results suggest that local ADP buffering by PCr is essential for normal Ca2+ regulation by the SR. Prolongation of the descending phase of the spontaneous Ca2+ transient is consistent with a reduction in the efficiency of the SR Ca2+ pump due to ADP accumulation. The fact that spontaneous Ca2+ release occurs at a lower SR Ca2+ content in the absence of PCr suggests that the Ca2+ release mechanism may also be affected. These effects may be of relevance in circumstances where PCr depletion and Ca2+ overload occur, such as myocardial ischaemia or anoxia.
Central and peripheral mediation of human force sensation following eccentric or concentric contractions
Authors: Carson Richard G. , Riek Stephan , Shahbazpour Nosratollah
Published: July 2002

Fatigue was induced in the triceps brachii of the experimental arm by a regimen of either eccentric or concentric muscle actions. Estimates of force were assessed using a contralateral limb‐matching procedure, in which target force levels (25 %, 50 % or 75 % of maximum) were defined by the unfatigued control arm. Maximum isometric force‐generating capacity was reduced by 31 % immediately following eccentric contractions, and remained depressed at 24 (25 %) and 48 h (13 %) post‐exercise. A less marked reduction (8.3 %) was observed immediately following concentric contractions. Those participants who performed prior eccentric contractions, consistently (at all force levels), and persistently (throughout the recovery period), overestimated the level of force applied by the experimental arm. In other words, they believed that they were generating more force than they actually achieved. When the forces applied by the experimental and the control arm, were each expressed as a proportion of the maximum force that could be attained at that time, the estimates matched extremely closely. This outcome is that which would be expected if the estimates of force were based on a sense of effort. Following eccentric exercise, the amplitude of the EMG activity recorded from the experimental arm was substantially greater than that recorded from the control arm. Cortically evoked potentials recorded from the triceps brachii (and extensor carpi radialis) of the experimental arm were also substantially larger than those elicited prior to exercise. The sense of effort was evidently not based upon a corollary of the central motor command. Rather, the relationship between the sense of effort and the motor command appears to have been altered as a result of the fatiguing eccentric contractions. It is proposed that the sense of effort is associated with activity in neural centres upstream of the motor cortex.
Four cell types with distinctive membrane properties and morphologies in lamina I of the spinal dorsal horn of the adult rat
Authors: Prescott Steven A. , Koninck Yves De
Published: July 2002

Lamina I of the spinal dorsal horn plays an important role in the processing and relay of nociceptive information. Signal processing depends, in part, on neuronal membrane properties. Intrinsic membrane properties of lamina I neurons were therefore investigated using whole cell patch clamp recordings in a slice preparation of adult rat spinal cord. Based on responses to somatic current injection, four cell types were identified: tonic, which fire comparatively slowly but continuously throughout stimulation; phasic, which fire a high frequency burst of variable duration; delayed onset, which fire irregularly and with a marked delay to the first spike; and single spike, which typically fire only one action potential even when strongly depolarised. Classification by spiking pattern was further refined by identification of characteristic stimulus‐response curves and quantification of several response parameters. Objectivity of the classification was confirmed by cluster analysis. Responses to stimulus trains and synaptic input as well as the kinetics of spontaneous synaptic events revealed differences in the signal processing characteristics of the cell types: tonic and delayed onset cells appeared to act predominantly as integrators whereas phasic and single spike cells acted as coincidence detectors. Intracellular labelling revealed a significant correlation between morphological and physiological cell types: tonic cells were typically fusiform, phasic cells were pyramidal, and delayed onset and single spike cells were multipolar. Thus, there are multiple physiological cells types in lamina I with specific morphological correlates and distinctive signal processing characteristics that confer significant differences in the transduction of input into spike trains.
Voltage independence of vasomotion in isolated irideal arterioles of the rat
Authors: Haddock R. E. , Hirst G. D. S. , Hill C. E.
Published: July 2002

The cellular mechanisms underlying vasomotion of irideal arterioles from juvenile rats have been studied using electrophysiological methods, ratiometric calcium measurements and video microscopy. Vasomotion was not affected by removal of the endothelium. Spontaneous contractions were preceded by spontaneous depolarizations. Both were abolished by the intracellular calcium chelator, BAPTA AM (20 μm), but not by ryanodine (10 μm), suggesting a dependence on the cyclical release of calcium from intracellular stores, other than those operated by ryanodine receptors. Oscillations were little changed when the membrane potential of short segments of arteriole was either depolarized or hyperpolarized. When the segments were voltage clamped, oscillating inward currents were recorded, indicating that the changes in membrane potential were voltage independent. Vasomotion was preceded by intracellular calcium oscillations and both were abolished by inhibitors of phospholipase C (U73122, 10 μm), phospholipase A2 (AACOCF3, 30 μm) and protein kinase C (chelerythrine chloride, 5 μm, and myristoylated protein kinase C peptide, 10 μm). Inhibition of vasomotion by the dual lipoxygenase and cyclo‐oxygenase inhibitor, NDGA (10 μm), the lipoxygenase inhibitor, ETI (1 μm) but not by the cyclo‐oxygenase inhibitors, aspirin (10 μm) and indomethacin (10 μm), or the cytochrome P450 inhibitor 17‐ODYA (10 μm), suggested an involvement of the lipoxygenase pathway. The observations suggest that vasomotion of iris arterioles is voltage independent and results from the cyclical release of calcium from IP3‐sensitive stores which are activated by cross talk between the phospholipase C and phospholipase A2 pathways in vascular smooth muscle.
Subtypes of NMDA receptors in new‐born rat hippocampal granule cells
Authors: Piña‐Crespo Juan C. , Gibb Alasdair J.
Published: July 2002

To investigate the properties of NMDA receptors expressed in new‐born rat hippocampal granule cells, recordings were made of single‐channel currents produced by application of glutamate or NMDA to outside‐out membrane patches. Outside‐out patches displayed two distinct patterns of single‐channel activity. In some patches only high conductance single‐channel activity composed of 42 and 50 pS currents was observed while in others both high (42 and 50 pS) and low (17 and 33 pS) conductance single‐channel currents occurred. An absence of direct transitions connecting the smallest (17 pS) and largest (50 pS) conductance unitary currents, as well as an absence of direct transitions connecting 17, 42 and 50 pS currents in sequence, suggested that high and low conductance single‐channel activity may have been produced as a result of the activation of two distinct NMDA receptor populations. The NR2B subunit‐selective NMDA receptor antagonist, ifenprodil, blocked the high conductance currents suggesting that these receptors contain the NR2B subunit while a clear asymmetry in the frequency of direct transitions between 17 and 42 pS conductance levels indicates the presence of NMDA receptors containing NR2D subunits. In patches containing both high and low conductance‐channel activity, evidence for negative coupling between NR2B‐ and NR2D‐like channel activity was observed, suggesting receptors containing these subunits do not gate independently or that both NR2B and NR2D subunits may be part of a single receptor molecule. We conclude that NMDA receptors in P0 hippocampal granule cells are likely to be a mixture of NR1/NR2B diheteromers and receptors of novel molecular composition that may be triheteromeric receptors composed of NR1, NR2B and NR2D subunits.
Analysis of Hydroelastic Instabilities of Rectangular Parallel-Plate Assemblies
Authors: Guo C. Q. , Paı¨doussis M. P.
Published: July 2002

Flow-induced vibrations and hydroelastic instabilities of rectangular parallel-plate assemblies are studied theoretically. The extended Galerkin method is employed to solve the plate equation, while the Fourier transform technique is used to solve for the perturbation pressure from the potential flow equations. The mixed fluid-plate interaction boundary condition leads to a singular integral equation, which is solved numerically. The complex frequencies versus flow velocity and critical velocities are obtained for various plate aspect ratios and channel-height-to-plate-width ratios. The frequencies and critical velocities are found to decrease as the plate length increases and as the channel height decreases. Two types of instability are found, namely, single-mode divergence, mostly in the first mode, and coupled-mode flutter involving adjacent modes. Damping has a significant effect on post-divergence stability and coupled-mode flutter of the system. [S0094-9930(00)00403-0]
Predicted Effects of Cylinder Kit Wear on Blowby and Oil Consumption for Two Diesel Engines
Authors: Richardson D. E. , Krause S. A.
Published: July 2002

Durability is very important for current diesel engines. Diesel engine manufacturers are trying to make the engines live as long as possible before overhaul. The time to overhaul for an engine is usually dictated by high oil consumption or blowby. Therefore, it is necessary to understand how wear affects the cylinder kit dynamics, oil consumption, and blowby in an engine. This paper explores the effect of power cylinder component (rings and cylinder bore) wear by using a cylinder kit dynamics model. The model predicts how wear will affect ring motion, inter-ring gas pressure, blowby, etc. The parameters studied were: liner wear, ring face wear, and ring side wear. Two different engines were modeled. The characteristics of these two engines are very different. As a result, the effects of wear are different and the corresponding durability will be different. This illustrates the need to model each individual type of engine separately. The modeling shows that top ring face wear is very significant for maintaining good oil and blowby control. Liner wear is important, but does not have as large an effect as ring wear. The effects of side wear are significant for these two cases. [S0742-4795(00)00203-9]
The Use of Cavitating Jets to Oxidize Organic Compounds in Water
Authors: Kalumuck K. M. , Chahine G. L.
Published: July 2002

Exposure to ultrasonic acoustic waves can greatly enhance various chemical reactions. Ultrasonic acoustic irradiation of organic compounds in aqueous solution results in oxidation of these compounds. The mechanism producing this behavior is the inducement of the growth and collapse of cavitation bubbles driven by the high frequency acoustic pressure fluctuations. Cavitation bubble collapse produces extremely high local pressures and temperatures. Such conditions are believed to produce hydroxyl radicals which are strong oxidizing agents. We have applied hydrodynamic cavitation to contaminated water by the use of submerged cavitating liquid jets to trigger widespread cavitation and induce oxidation in the bulk solution. Experiments were conducted in recirculating flow loops using a variety of cavitating jet configurations and operating conditions with dilute aqueous solutions of p-nitrophenol (PNP) of known concentration. Temperature, pH, ambient and jet pressures, and flow rates were controlled and systematically varied. Samples of the liquid were taken and the concentration of PNP measured with a spectrophotometer. Experiments were conducted in parallel with an ultrasonic horn for comparison. Submerged cavitating liquid jets were found to generate a two order of magnitude increase in energy efficiency compared to the ultrasonic means. [S0098-2202(00)00303-5]
Rough Wall Turbulent Boundary Layers in Shallow Open Channel Flow
Authors: Tachie M. F. , Bergstrom D. J. , Balachandar R.
Published: July 2002

An experimental study was undertaken to investigate the effects of roughness on the structure of turbulent boundary layers in open channels. The study was carried out using a laser Doppler anemometer in shallow flows for three different types of rough surface, as well as a hydraulically smooth surface. The flow Reynolds number based on the boundary layer momentum thickness ranged from 1400 to 4000. The boundary layer thickness was comparable with the depth of flow and the turbulence intensity in the channel flow varied from 2 to 4 percent. The defect profile was correlated using an approach which allowed both the skin friction and wake strength to vary. The wake parameter was observed to vary significantly with the type of surface roughness in contradiction to the “wall similarity” hypothesis. Wall roughness also led to higher turbulence levels in the outer region of the boundary layer. The profound effect of surface roughness on the outer region as well as the effect of channel turbulence on the main flow indicates a strong interaction, which must be accounted for in turbulence models. [S0098-2202(00)00803-8]
Performance Shaping Factors in Reliability Analysis of Design of Offshore Structures
Authors: Bea R. G.
Published: July 2002

This paper summarizes development of a process that provides a link between a qualitative assessment and a quantitative probability analysis that can be used to help evaluate the reliability of offshore structures during the design phase. The qualitative analysis is used to define performance shaping factors that are used to modify standard or normal rates of occurrence of design engineering errors in different tasks. When used by qualified and experienced assessors, the qualitative analysis is able to help evaluate complex, organic, human, and organizational factors that are not easily evaluated using quantitative analyses. Detailed studies of case histories involving successful and unsuccessful design of offshore structures have been used to develop a calibrated scale to relate the results from a qualitative assessment with input information used in a quantitative probabilistic risk analysis. [S0892-7219(00)01103-1]
Spectral Characteristics of Sheet/Cloud Cavitation
Authors: Kjeldsen Morten , Arndt Roger E. A. , Effertz Mark
Published: July 2002

Cavitation observations were made using a highly instrumented 2D NACA 0015 hydrofoil mounted in a specially designed water tunnel. It was found that the dynamic characteristics of the cavitation vary considerably with various combinations of angle of attack and cavitation number, σ. At higher angles of attack, two types of flow unsteadiness are observed. At low σ, a low frequency shedding of cloud cavitation results in a strong oscillation in lift and Δp at a Strouhal number, based on chord length, fc/U, of about 0.15. This frequency is relatively insensitive to changes in σ. As σ is raised, the harmonic content of the oscillations changes significantly. A spectral peak at much higher frequency is noted that increases in frequency almost linearly with cavitation number. Similar behavior is noted in the lift fluctuations. [S0098-2202(00)02503-7]
Transient and Cyclic Responses of Strain-Generated Potential in Rabbit Patellar Tendon Are Frequency and pH Dependent
Authors: Chen C. T. , McCabe R. P. , Grodzinsky A. J. , Vanderby, R.
Published: July 2002

The goal of this study was to expand understanding of strain-generated potential (SGP) in ligamentous or tendinous tissues. Most SGP studies in the past have focused on cartilage or bone. Herein, rabbit patellar tendon (PT) was used as a model. Each patellar tendon had two Ag/AgCl electrodes inserted at axial positions of 1/4 and 1/2 from patellar to tibial insertions. Each specimen was electrically isolated, gripped in a servohydraulic test system, and then subjected to a short session of uniaxial haversine tension (2.5 percent maximum strain) at a frequency of 0.5, 1.0, 2.0, or 5.0 Hz. A cyclic (sinusoidal) electrical potential superimposed upon a larger transient (exponentially asymptotic) potential was consistently observed. Upon termination of loading, the cyclic SGP ended, and the shifted baseline of the SGP exponentially decayed and asymptotically returned to a residual potential which over all specimens was not different than the original potential. The transient and cyclic SGPs were frequency dependent (P<0.001,P=0.06, respectively). To our knowledge, this transient portion of the SGP, although theoretically predicted by Suh (1996, Biorheology, 33, pp. 289–304) and Chen (1996, Ph.D. thesis, University of Wisconsin—Madison) has not been observed in other experiments using different protocols. Additional PTs were dehydrated and the rehydrated in solution at different pH levels. The magnitude of SGPs increased in basic solution (pH 9.5) but diminished in pH 4.7 buffer. This pH dependency suggests that electrokinetics is the dominant mechanism for the transient and cyclic responses of the SGPs, although this study does not provide direct evidence. [S0148-0731(00)00105-9]
Film Cooling Effectiveness for Short Film Cooling Holes Fed by a Narrow Plenum
Authors: Hale C. A. , Plesniak M. W. , Ramadhyani S.
Published: July 2002

The adiabatic, steady-state liquid crystal technique was used to measure surface adiabatic film cooling effectiveness values in the near-hole region X/D<10. A parametric study was conducted for a single row of short holes L/D⩽3 fed by a narrow plenum H/D=1. Film cooling effectiveness values are presented and compared for various L/D ratios (0.66 to 3.0), three different blowing ratios (0.5, 1.0, and 1.5), two different plenum feed configurations (co-flow and counterflow), and two different injection angles (35 and 90 deg). Injection hole geometry and plenum feed direction were found to affect short hole film cooling performance significantly. Under certain conditions, similar or improved coverage was achieved with 90 deg holes compared with 35 deg holes. This result has important implications for manufacturing of thin-walled film-cooled blades or vanes. [S0889-504X(00)00603-6]