bluuebunny/crossref_metadata_2025 huggingface dataset:
UNDERSTANDING PUBLIC ADMINISTRATION: REFLECTIONS ON AN ACADEMIC OBITUARY —“ALAS, POOR YORICK”
Authors: Spann R. N.
Published: March 2008

It seemed that “Alas, Poor Yorick” was an appropriate subtitle for this attempt to respond to Understanding Public Administration. Yorick, you will remember, was the deceased royal jester, whose skull Hamlet inspected in the churchyard in Elsinore, causing him to meditate on the vanity of human life. “Now get you to my lady's chamber, and tell her, let her paint an inch thick, to this favour she must come.” Though not a professional jester, I am keenly aware of the ephemeral character of the work of Professors of Government and Public Administration, or at least of this particular one; though Festsehriften may be said to “lay it on thick”, they cannot altogether disguise the rather plain face beneath. I am glad to be fortified by having the more distinguished countenance of Robert Parker alongside me, and I mean that.
ECONOMICS DEGREES AND THE AUSTRALIAN PUBLIC SERVICE: A NOTE*
Authors: Petridis A.
Published: March 2008

At present the Australian Public Service employs about 14,000 university graduates, one quarter of whom have majored in economics, usually in an economics, commerce, arts (economics) or science (economics) degree. As can be seen from Table 1, this proportion of economics degrees to total degrees has remained fairly constant over the last decade. It is a reflection of the great emphasis placed on the recruitment of graduates in economics to the APS since the war, and especially since 1960.
SCIENCE IN A PUBLIC SERVICE ENVIRONMENT: ARE STATUTORY AUTHORITIES THE ANSWER?*
Authors: Sparrow J. G.
Published: March 2008

Abstract: The Royal Commission on Australian Government Administration reported evidence of widespread morale problems among government scientists. A major contributing cause was seen as the environment under which science is conducted within a departmental structure. One solution which has been advocated by many scientists, although rejected by the RCAGA, is to transfer government scientific laboratories into statutory authorities.
POLITICS AND REGULATION: THE PUBLIC CHOICE APPROACH
Authors: Conybeare John A. C.
Published: March 2008

Abstract: Government regulation of the economy has been the subject of criticism both on the grounds of efficiency and equity. Traditional economic theories explaining regulation may be deficient insofar as they assume a benevolent welfare maximizing government, intervening only to correct “market failures”. Political theories of interest group influence (for example pluralist, capture, Marxist theories) provide some more realistic insights into regulation, but fail to yield rigorous, testable propositions. The theory of public choice applies the rigour of economic analysis to political behaviour and suggests some useful approaches to the explanation of regulation, focusing on the public goods problem of organizing large groups of actors for collective action and on the role of the political entrepreneur in mobilizing large numbers of voters. The public choice approach may also be useful in suggesting strategies for deregulation in some key areas of the Australian economy currently under scrutiny (for example banking, airlines, telecommunications).
LABOR'S UNKNOWN EXPERIMENT: THE MORETON REGIONAL COORDINATION EXERCISE*
Authors: Carey Bernard
Published: March 2008

Abstract: The Department of Urban and Regional Development's (DURD's) Moreton Regional Coordination Exercise was a bold experiment. It aimed to coordinate, at a regional level, the activities of all levels of government, an objective close to DURD's heart. The proposal emerged from DURD's struggles with other commonwealth departments, conflicts with the Queensland government over administrative arrangements for the Area Improvement Program and the Australian Assistance Plan, and representations from the Lord Mayor of Brisbane concerning regional arrangements. In the course of setting the exercise up, DURD faced many difficulties, including departmental opposition on the interdepartmental committees and the scepticism of officials at the regional level. In implementing the idea of a regional budget there were serious shortcomings in available information and major difficulties in overcoming the inertia of existing departmental budgetary routines and priorities. The Regional Team of officials produced a report that was redolent of general support for “better coordination”, but the specific proposals and their effectiveness were very limited. DURD's coordinating ambitions were thwarted, despite apparent Cabinet support and oversight by a special Cabinet committee. In fact, Cabinet as an institution was too weak and its membership too fragmented to provide the necessary power to overcome bureaucratic conservatism.
MINISTERIAL STAFF UNDER HAWKE
Authors: Walters James
Published: March 2008

Abstract: The establishment by the present Labor government of an advisory panel on ministerial staff appointments is discussed. It is suggested that this procedure had political benefits, but did not significantly influence the composition of the ministerial staff group. The ministerial staff of the ALP government are described and compared with those of the previous ALP government 1972‐75, and of the Liberal‐National Party coalition government 1975‐83. It is found that there has been a weakening of the bureaucratic element in this government's private offices compared with both the coalition government and the previous Labor government. The ascendance of “political types” is matched by a commitment to the party program and a high estimate among staffers of their contribution to the policy‐making process. In other respects this group shares with its predecessors the characteristics of being mostly male, relatively young, highly educated and disproportionately from non‐government schools. About half are from inside and half from outside the public service.
RECONCILING THE IRRECONCILABLE? THE RESOURCE ASSESSMENT COMMISSION, RESOURCES POLICY AND THE ENVIRONMENT*
Authors: Economou Nicholas M.
Published: March 2008

Abstract: This paper investigates the place of the Resource Assessment Commission (RAC) in the reform of resource policy‐making undertaken by the Hawke government in the aftermath of its experience of the Wesley Vale pulp‐mill dispute. The paper argues that the RAC was seen as a foundation upon which the reformed process would rest. The RAC's role would conform to the essence of “accordism”—that is, it would seek to depoliticise information and scientific data by filtering the wide range of inputs at the evaluative stage whilst attempting to reconcile hitherto irreconcilable interest groups from the development and environment sides of the land‐use debate. The paper begins by exploring the origins of the RAC. It then reviews the RAC in action and concludes by analyzing the role of the commission within the broader context of the Hawke government's pursuit of “consensus politics”.
TOWARDS WORLD‐BEST PRACTICE IN ENGINEERING EDUCATION
Authors: Darvall Peter
Published: March 2008

Abstract: As Australia struggles to become technologically competitive and to raise its productivity to international standards, several reports have suggested that such productivity depends critically on the existence of an appropriately structured and trained engineering workforce. As a result, engineering education at all levels has come under close scrutiny and rapid change in the period 1987–92. The scrutiny has come from governments, industry and from the engineering profession itself. Some of the changes are consequent to wider administrative changes in education; others are inspired by industry training needs; still others have been brought about by the engineering education community in order to attract more high‐quality students. The binary system of higher education has given way to a unified system. The state‐controlled TAFE colleges are being brought under national standards. In engineering education a new three‐year BTech degree is being promoted to fill the gap between two‐year associate diplomas from TAFE colleges and four‐year professional degrees from the universities, because of a serious shortage of para‐professional engineers in Australian industry. Recent reviews and reports on engineering education have called for rapid expansion at all levels and a greater variety of courses. The use of competency standards is spreading from the trade levels into the professions, including engineering, threatening some traditional concepts of university education. The government has funded three Advanced Engineering Centres, modelled on institutes in other countries. Quality in higher education is under discussion, bringing the concepts of total quality management and world‐best practice to teaching in the universities. Continuing professional education is being rapidly expanded by the Institution of Engineers, Australia. Many more women are now entering the engineering profession, attracted by the humanisation of engineering courses. Environmental engineering and combined degree courses are proving very popular. The level of technological awareness is being improved by bringing engineering students to assist in classes in primary and secondary schools. Cooperative education programs between universities and industry are proving attractive and effective.
QUALITY COST IN THE PUBLIC SERVICE: IDENTIFYING, MEASURING AND REPORTING
Authors: Navaratnam K.K.
Published: March 2008

Abstract: The identification, collection, and reporting of quality costs are necessary to achieve efficiency in the delivery of public service. This paper argues that quality costs are major elements in the total costs of delivering programs and services in the public service. To support this point, a seven‐step system is described that could be used to develop a feasible modification of existing charts of account to incorporate quality cost elements. Incorporation of quality cost elements in the financial accounting system would enable the public service to use quality costs in the current wave of performance management of programs and services to bring about reliable and valid efficiency measures of deliveryfunctions.
ECONOMIC THEORY AND POLICY ANALYSIS: CONCEPTUAL GUIDELINES FOR PUBLIC POLICY‐MAKERS
Authors: Dollery B. E.
Published: March 2008

Abstract: Traditionally public policy analysis has been able to employ the conceptual framework offered by the theory of market failure in order to evaluate the efficiency of market outcomes. However, until fairly recently, no corresponding analytical structure existed which could facilitate the examination of the efficiency and equity characteristics of government or non‐market outcomes. Quite apart from public choice theory, an embryonic normative theory of government failure has now been developed which can act as a conceptual analogue to the market failure paradigm. At present, three theories of government failure coexist in the literature: Wolf's theory of non‐market failure; Le Grand's theory of government failure; and Vining and Weimer's theory of govern‐ ment production failure. These models form the basis for a more universal theory of government failure. Nevertheless, in its current state of development this seminal literature can still assist in rational public policy design subject to certain caveats. Foremost amongst these is the need for policy analysts to augment the efficiency and equity criteria with some additional broader normative measures, and the necessity for care to be taken in the use of allocative efficiency as a benchmark in non‐market circumstances.
PUBLIC ADMINISTRATION AND AUSTRALIAN ENGAGEMENT WITH ASIA
Authors: Turner Mark
Published: March 2008

Public Administration in Asia and the Pacific: Survey of Teaching and Research in Twelve Countries. Edited by Ledivina Caring

Administrative Reform Towards Productivity in Bureaucratic Performance. Edited by Zhang Zhijian, Raul P. De Guzman And Mila A. Reforma

Politics and Administration in Changing Societies: Essays in Honour of Professor Fred W. Riggs. Edited by Ramesh K. Arora
The Premises of Decision‐Making within the Australian Public Service
Authors: Matheson Craig
Published: March 2008

Decision‐making is usually studied in the context of a particular choice or institution. This article proposes an alternative, cross‐cutting approach. It argues that federal policy‐making involves three forms of rationality — technical, economic and political. Standard operating procedures develop around each. This simplifies much decisionmaking but may also produce narrowness of outlook and a failure to see other dimensions to a policy problem.
Modern Central Banking: Pressures for Change
Authors: Hawtrey KM
Published: March 2008

The role of the central bank as an instrument of government economic supervision has entered a period of flux, owing to the combined forces of financial deregulation, technological advance, monetary innovation and banking globalisation. This paper discusses, with special reference to Australia, pressing areas for potential reform in the role of the central bank including greater independence, international coordination, splitting of core functions, and the creation of a ‘super‐regulator’.
Computer‐Based Performance Information for Executives in Local Government
Authors: Hasan Helen , Hasan Suzanne
Published: March 2008

Performance information is crucial to effective management. Computer‐based information systems (CBIS) now play a significant role in the effective delivery of information to senior managers. Executive information systems (EIS) are emerging as popular tools to assist organisations in their strategic decision‐making processes. This trend has spread from the private to the public sector, and is now evident in Australian government organizations

This article draws on the findings of a survey into the uses and benefits of CBIS and EIS, from a sample of Australian local government organisations. The study shows that lessons from the private sector are being heeded by system developers in public organisations, leading to successful EIS projects, or at least improved CBIS. The study indicates that EIS, which were originally developed for profit‐oriented private companies, are now seen as appropriate for many public sector organisations, providing effective delivery of information to senior managers. Survey results indicate that improved information systems give executives a more accurate picture of their organisation's performance and so provide support for improved strategic decision‐making. In addition, EIS are seen by respondents as offering significant benefits not only to managers but also to the rest of the organization.
The Better Practice Program Funding Formula: A Neo‐liberal Approach to Funding General Practice
Authors: Dugdale Paul
Published: March 2008

A decade after the introduction of Medicare, various pressures had emerged in the financing of general practice. The National Health Strategy suggested these could be addressed by supplementing the Medicare benefits program with other payment systems. The Commonwealth government introduced the better practice program (BPP) in late 1994. Through the BPP, the Commonwealth makes payments to general practices calculated according to a formula. Using Medicare claims data, the formula takes into account practice size, patient loyalty to the practice and practice location. The BPP formula is oriented to the free choice of doctor by patients, and free choice of practice location by doctors. It is the exercise of these freedoms that, through the operation of the formula, determines the size of BPP payments. This arrangement is an example of a distinctively neo‐liberal mode of government.
Performance Standards and Evaluation
Authors: AM Pat Barrett
Published: March 2008

The benefits of performance monitoring for public services are identified as greater transparency of objectives and accountability for results. This article considers recent experience in developing standards to evaluate efficiency and effectiveness of public services. In broad terms this is being done through performance information which is a much more encompassing concept than standards or indicators. Such information is an element of an accountability framework that provides greater management autonomy and flexibility and extends to the private sector which is increasingly providing, or involved with the provision of, public services.
Evaluating Equity Outcomes in State Public Sectors: A Comparison of Three Housing Agencies
Authors: Brown Kerry
Published: March 2008

In this article, state public sector Equal Employment Opportunity (EEO) outcomes of housing agencies in three states, New South Wales, Queensland and Western Australia are analysed and compared. EEO policies, programs and subsequent outcomes for women in the areas of reducing gender‐based job segregation and income disparities, providing avenues for career progression and access to non‐traditional jobs are evaluated to determine how different types of administrative and managerial structures influence equity outcomes. The research addresses the question of whether a centralised administrative structure or a devolved corporate management approach provides a more appropriate model for delivering public sector equity policies and programs. The case study findings indicate that a traditional administrative structure based on central control provides no guarantee of better equity results.
‘Can Governments Weather the Storm in the New Communications Climate?’
Authors: Hughes Patrick
Published: March 2008

Government policies of privatisation, contracting‐out and de‐regulation have been major driving forces of globalisation in and through the communications industry. Ironically, however, globalism makes it increasingly difficult for national and state governments to influence the communications industry at national and state levels respectively. This article argues that globalism challenges governments to manage and develop their own communications systems and activities in ways which counter some of the major features of globalism in the communications industry. The article advocates rolling communications strategies at state and federal levels and outlines ways in which such strategies could develop.
Revising Our Expectations of Local Government
Authors: Dore Janet
Published: March 2008

Significant reform of local government in Victoria has led the way nationally and arguably gone beyond the comparative New Zealand and English experiences. Since the reforms were introduced and elected councillors were returned during 1996 and 1997, there has been an adjustment of roles and responsibilities with varying degrees of acceptance. Reviewing the Victorian experience leads to exploration of the potential within local government to define a strong strategic development role based on larger units of economic influence. This will require continuing cultural change within organisations and a wider focus of responsibility for elected members to rise above the ‘pot hole’ mentality. Regional Australia will be especially poorly served if this challenge is not taken up. This article reviews the progress of compulsory competitive tendering in Victoria by using a case study of the experience in Ballarat.
With the Benefit of Foresight and a Little Help from Hindsight
Authors: CH Rt Hon David Lange
Published: March 2008

This article is about New Zealand's recent experience in public sector reform. New Zealand became seized with economic rationalism about the same time as Australia did but at the national level we went faster and farther than Australia towards the creation of a commercial culture in the public sector. Here I discuss what might be learned from what has happened in New Zealand.
Should the High Court Consider Policy?
Authors: Winterton George
Published: March 2008

Courts may take into account policy considerations and social values far more than we often care to admit. Although some judges stress the importance of the ‘judicial method’, others have been more forthright about influences on judicial decisions. This contribution suggests that policy considerations are unavoidably involved in judicial judgments.
Introduction: The State of State Employment
Authors: O'Brien John , Hort Linda
Published: March 2008

Public sector industrial relations is a somewhat neglected field of investigation. The relative neglect by industrial relations scholars is surprising given that public sector employees in Australia are much more likely to be unionised and work within larger organisations with formalised industrial. Moreover, it has been within public sector environments where the efficacy of public policy directions in industrial relations have been tested. Public sector environments are more likely to be characterised by structured bargaining and policy testing than much of the private sector. One of the purposes of this symposium, then, is to remedy this relative neglect of public sector industrial relations.
ACTU View of the Industry Commission Report on Competitive Tendering and Contracting
Authors: Lee Tim , Moylan Peter
Published: March 2008

This report presents a critique of the Industry Commission's final report entitled Competitive Tendering and Contracting by Public Sector Agencies (1996). From a trade union perspective, the authors raise many concerns about the methodology, ideology and findings of the Industry Commission report.
Viability of AS‐3 and SAG‐M red cells stored in plastic syringes for pediatric transfusion
Authors: Podlosky Linda , Poirier Amanda , Nahirniak Susan , Clarke Gwen , Acker Jason P.
Published: March 2008

BACKGROUND: Pediatric patients may require small‐volume transfusions necessitating splitting of red cell (RBC) units. This process usually involves temporary storage of aliquots in pediatric blood bags or, in some cases, plastic syringes, until they are transfused. While many studies have been published on the efficacy of storage in blood bags, there is little evidence to show that RBCs are safe and effective for transfusion after separation into plastic syringe aliquots.

STUDY DESIGN AND METHODS: Donor RBC units, stored in either SAG‐M (n = 10) or AS‐3 additive (n = 11), were split into transfer bags and plastic syringes and stored at either 4°C or room temperature (RT). Half of the aliquots were also irradiated at 25 Gy. RBCs were monitored after 0, 4, and 24 hours of storage with the following variables to assess cellular function and viability: adenosine triphosphate, percent hemolysis, hematocrit, pH, lactate dehydrogenase, extracellular potassium, sodium, and RBC indices.

RESULTS: There was no difference found between irradiated and nonirradiated aliquots or aliquots stored in the refrigerator versus those stored at RT. Significant differences between aliquots stored in approved transfer bags and those stored in syringes were not identified.

CONCLUSIONS: Irradiation and storage of aliquoted RBCs demonstrated expected but not significant changes in the in vitro variables. Storage for up to 24 hours in syringes does not have a greater detrimental effect on RBCs than storage in transfer bags, making products stored in either container safe for transfusion to pediatric patients.
Photosensitivity skin disorders in childhood
Authors: Horkay Irene , Emri Gabriella , Varga Viktoria , Simics Eniko , Remenyik Eva
Published: March 2008

Photosensitivity in childhood is caused by a diverse group of diseases. It usually indicates idiopathic photodermatoses, first of all polymorphic light eruption. It may be an early symptom of genetic disorders such as porphyria or very rare genophotodermatoses. Photosensitivity secondary to topical or systemic external agents as well as photoexacerbated dermatoses is not so frequent in childhood. Here we present our experience with childhood photosensitivity skin diseases collected over a 40‐year period.
Double‐sigmoid model for fitting fatigue profiles in mouse fast‐ and slow‐twitch muscle
Authors: Cairns S. P. , Robinson D. M. , Loiselle D. S.
Published: March 2008

We present a curve‐fitting approach that permits quantitative comparisons of fatigue profiles obtained with different stimulation protocols in isolated slow‐twitch soleus and fast‐twitch extensor digitorum longus (EDL) muscles of mice. Profiles from our usual stimulation protocol (125 Hz for 500 ms, evoked once every second for 100–300 s) could be fitted by single‐term functions (sigmoids or exponentials) but not by a double exponential. A clearly superior fit, as confirmed by the Akaiki Information Criterion, was achieved using a double‐sigmoid function. Fitting accuracy was exceptional; mean square errors were typically <1% and r2 > 0.9995. The first sigmoid (early fatigue) involved ∼10% decline of isometric force to an intermediate plateau in both muscle types; the second sigmoid (late fatigue) involved a reduction of force to a final plateau, the decline being 83% of initial force in EDL and 63% of initial force in soleus. The maximal slope of each sigmoid was seven‐ to eightfold greater in EDL than in soleus. The general applicability of the model was tested by fitting profiles with a severe force loss arising from repeated tetanic stimulation evoked at different frequencies or rest periods, or with excitation via nerve terminals in soleus. Late fatigue, which was absent at 30 Hz, occurred earlier and to a greater extent at 125 than 50 Hz. The model captured small changes in rate of late fatigue for nerve terminal versus sarcolemmal stimulation. We conclude that a double‐sigmoid expression is a useful and accurate model to characterize fatigue in isolated muscle preparations.
Pontomedullary transection attenuates central respiratory modulation of sympathetic discharge, heart rate and the baroreceptor reflex in thein siturat preparation
Authors: Baekey David M. , Dick Thomas E. , Paton Julian F. R.
Published: March 2008

Previous studies have indicated a major role for the pons in the genesis of the respiratory pattern. The respiratory rhythm is coupled to the cardiovascular system to ensure optimal matching of minute ventilation and cardiac output. Since much of this coupling results from cross‐talk between brainstem circuits, we have assessed the role of the pons in both the co‐ordination of respiratory and cardiovascular efferent activities and the baroreceptor reflex efficacy. Using the arterially perfusedin siturat preparation, we recorded neural activities from the left phrenic nerve, central end of the vagus nerve, thoracic sympathetic chain (T8–T10) and heart rate. Respiratory sinus arrhythmia, respiratory modulation of sympathetic nerve activity (and Traube–Hering waves in arterial pressure) and postinspiratory discharges recorded from vagal efferents were eliminated after pontine transection. We also found that although the sympathetic arterial baroreflex remained intact, respiratory gating of the baroreceptor reflex (i.e. both bradycardia and sympathoinhibition) was abolished after pontine removal. We propose that neural activity of the pons is essential for physiological coupling of centrally generated respiratory and cardiovascular efferent activities.
Using Physiome standards to couple cellular functions for rat cardiac excitation–contraction
Authors: Terkildsen Jonna R. , Niederer Steven , Crampin Edmund J. , Hunter Peter , Smith Nicolas P.
Published: March 2008

Scientific endeavour is reliant upon the extension and reuse of previous knowledge. The formalization of this process for computational modelling is facilitated by the use of accepted standards with which to describe and simulate models, ensuring consistency between the models and thus reducing the development and propagation of errors. CellML 1.1, an XML‐based programming language, has been designed as a modelling standard which, by virtue of its import and grouping functions, facilitates model combination and reuse. Using CellML 1.1, we demonstrate the process of formalized model reuse by combining three separate models of rat cardiomyocyte function (an electrophysiology model, a model of cellular calcium dynamics and a mechanics model) which together make up the Pandit–Hinch–Niederer et al. cell model. Not only is this integrative model of rat electromechanics a useful tool for cardiac modelling but it is also an ideal framework with which to demonstrate both the power of model reuse and the challenges associated with this process. We highlight and classify a number of these issues associated with combining models and provide some suggested solutions.
The action of nitric oxide to enhance cell survival in chick cardiomyocytes is mediated through a cGMP and ERK1/2 pathway while p38 mitogen‐activated protein kinase‐dependent pathways do not alter cell death
Authors: Rabkin Simon W. , Tsang Michael Y. C.
Published: March 2008

The objective of this study was to determine whether the dual action of nitric oxide (NO) on cardiomyocyte cell viability is mediated through p38 mitogen‐activated protein kinase (MAPK)‐induced cell death and extracellular signal‐regulated kinase (ERK1/2)‐mediated cell survival pathways, and whether either of these is mediated through a cGMP–protein kinase G (PKG) pathway. Cell viability of embryonic chick cardiomyocytes was assessed by the MTT assay, which is based on the ability of viable cells to reduce 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide. The NO donor sodium nitroprusside (SNP) produced a significant (P < 0.01) concentration‐dependent reduction in cell viability or increase in cell death. Sodium nitroprusside induced ERK1/2 phosphorylation, and the mitogen‐activated protein kinase (MEK1/2) inhibitor PD 98059 significantly increased cell death. In contrast, SB202190, a relatively selective inhibitor of p38 MAPK, did not affect SNP‐induced cell death. The cardioprotective effect of NO was prbably mediated in part via cGMP because 1H‐[1,2,4]oxadiazolo[4,3‐a]quinoxalin‐1‐one, a selective inhibitor of NO‐sensitive guanylyl cyclase, produced a significant enhancement of SNP‐induced cell death. In contrast, the PKG inhibitor KT5823 did not affect cell viability. In summary, these data suggest that NO, via stimulation of soluble guanylyl cyclase, activates MEK1/2 whose product, ERK1/2, protects against cell death. In contrast, SNP‐induced p38 MAPK activation does not modulate NO‐induced cardiomyocyte cell death. Not all cGMP targets affect NO‐induced cell death, since the PKG pathway does not enhance or suppress NO‐induced cardiomyocyte cell death. Enhancement of the ERK1/2 responses to NO may permit the beneficial effects of NO to predominate.
Rapid Flow of Passive Neutrophils Into a 4 μm Pipet and Measurement of Cytoplasmic Viscosity
Authors: Needham D. , Hochmuth R. M.
Published: March 2008

Neutrophils from five different individuals are isolated with a density separation technique. A total of 151 unactivated (passive) cells are rapidly aspirated at constant suction pressure and at room temperature into a pipet with a diameter of 4 μm. The suction pressures in excess of an initial yield threshold are 0.5, 1 and 2 kPa and are comparable to those encountered in the microcirculation. These pressures are well in excess of the small suction pressure of ~ 20 Pa that is required to form a static hemispherical bump on the cell. At a given aspiration pressure, the leading edge of an individual cell is “tracked” as it flows into the pipet. A theory based on the flow of a Newtonian liquid from either a hemisphere or a spherical segment into a cylinder is used to model the entry process. Both theory and experiment show that during most of the entry process the leading edge of the cell moves at a nearly constant velocity with a rapid acceleration at the end. For cells from five different individuals at the three different excess aspiration pressures, Newtonian theory gives a cytoplasmic viscosity of 135 ± 54 Pa·s and overall entry times of 3.3s (0.5 kPa), 1.6s (1 kPa) and 0.82s (2 kPa). These results and those of Evans and Yeung at lower aspiration pressures indicate that the complex cytoplasm inside unactivated neutrophils behaves as a nearly Newtonian fluid with a viscosity on the order of 102 Pa·s over almost a two order of magnitude range in aspiration pressure and, thus, rate of deformation.
Effects of Pulsatile Flow on Cultured Vascular Endothelial Cell Morphology
Authors: Helmlinger G. , Geiger R. V. , Schreck S. , Nerem R. M.
Published: March 2008

Endothelial cells (EC) appear to adapt their morphology and function to the in vivo hemodynamic environment in which they reside. In vitro experiments indicate that similar alterations occur for cultured EC exposed to a laminar steady-state flow-induced shear stress. However, in vivo EC are exposed to a pulsatile flow environment; thus, in this investigation, the influence of pulsatile flow on cell shape and orientation and on actin microfilament localization in confluent bovine aortic endothelial cell (BAEC) monolayers was studied using a 1-Hz nonreversing sinusoidal shear stress of 40 ± 20 dynes/cm2 (type I), 1-Hz reversing sinusoidal shear stresses of 20 ± 40 and 10 ± 15 dynes/cm2 (type II), and 1-Hz oscillatory shear stresses of 0 ± 20 and 0 ± 40 dynes/cm2 (type III). The results show that in a type I nonreversing flow, cell shape changed less rapidly, but cells took on a more elongated shape than their steady flow controls long-term. For low-amplitude type II reversing flow, BAECs changed less rapidly in shape and were always less elongated than their steady controls; however, for high amplitude reversal, BAECs did not stay attached for more than 24 hours. For type III oscillatory flows, BAEC cell shape remained polygonal as in static culture and did not exhibit actin stress fibers, such as occurred in all other flows. These results demonstrate that EC can discriminate between different types of pulsatile flow environments. Furthermore, these experiments indicate the importance of engineering the cell culture environment so as to include pulsatile flow in investigations of vascular endothelial cell biology, whether these studies are designed to study vascular biology and the role of the endothelial cell in disease processes, or are ones leading to the development of hybrid, endothelial cell-preseeded vascular grafts.
Design and Development of an Unconstrained Dynamic Knee Simulator
Authors: McLean C. A. , Ahmed A. M.
Published: March 2008

A dynamic knee simulator has been developed to allow in-vitro investigation of the mechanical response of the joint corresponding to dynamic functional activities, e.g., walking. In the simulator, the controlled inputs are the time-histories of three parameters of a given dynamic activity: the flexion angle, and the flexion/extension moment and tibial axial force components of the foot-to-floor reaction. A combination of stepping motors and electro-hydraulic actuators is used to apply to a knee specimen, simultaneously and independently, the specified load and/or displacement inputs while allowing unconstrained relative motion between the joint members. Satisfactory performance of the simulator has been established for walking gait conditions based on measurements on three fresh-frozen specimens.
Stiffening of the Femoral Head Due to Intertrabecular Fluid and Intraosseous Pressure
Authors: Ochoa J. A. , Sanders A. P. , Heck D. A. , Hillberry B. M.
Published: March 2008

The mechanical properties of cancellous bone, as measured from bone plug samples, have been widely documented. However, few tests have been attempted to explore the effects the intertrabecular contents may have on the load bearing capabilities. In this study, canine femoral heads were subjected to dynamic compressive strain cycles. The femoral heads were tested intact, as well as with disrupted boundary conditions of the continuous, intraosseous fluid space. A significant reduction in mechanical stiffness was observed when the fluid compartment boundary was disrupted by drilling a hole part way into the femoral neck. A finite element model of a typical femoral head showed that the stiffness change was not due to removal of material from the neck, hydraulic effects notwithstanding. Refilling the hole in the neck with saline solution and sealing the boundary restored the stiffness to the intact baseline level. However, an increase in the fluid pressure did not cause a statistically significant increase in the stiffness of the femoral head.
Steady Flow Through Collapsible Tubes: Measurements of Flow and Geometry
Authors: Elad D. , Sahar M. , Avidor J. M. , Einav S.
Published: March 2008

Compliant tubes attain a complex three-dimensional geometry when the external pressure exceeds the internal pressure and the tube is partially collapsed. A new technique for remote measurement of dynamic surfaces was applied to classical experiments with collapsible tubes. This work presents measurements of the threedimensional structure of the tube as well as pressure and flow measurements during static loading and during steady-state fluid flow. Results are shown for two tubes of the same material and internal diameter but with different wall thicknesses. The measured tube laws compare well with previously published data and suggest the possible existence of a similarity tube law. The steady flow measurements did not compare well with the one-dimensional theoretical predictions.
A Junction-Orifice-Fiber Entrance Layer Model for Capillary Permeability: Application to Frog Mesenteric Capillaries
Authors: Fu B. M. , Weinbaum S. , Tsay R. Y. , Curry F. E.
Published: March 2008

The recent serial section electron microscopic studies by Adamson and Michel (1993) on microves gels of frog mesentery have revealed that the large pores in the junction strand of the interendothelial cleft are widely separated 150 nm wide orifice-like breaks whose gap height 20 nm is the same as the wide part of the cleft. In this paper a modified version of the model in Weinbaum et al. (1992) is first developed in which this orifice structure is explored in combination with a random or ordered fiber matrix layer that is at the luminal surface and/or occupies a fraction of the wide part of the cleft. This basic orifice model predicts that for the measured Lp to be achieved the fiber layer must be confined to a relatively narrow region at the entrance to the cleft where it serves as the primary molecular filter. The model provides a much better fit of the permeability P for intermediate size solutes between 1 and 2 nm radius than the previous model in Weinbaum et al., where the junction strand breaks were treated as finite depth circular or rectangular pores, but like the previous model significantly underestimates P for small ions. However, it is shown that if a small frequent pore of 1.5 nm radius with characteristic spacing comparable to the diameter of the junction proteins or a continuous narrow slit of approximately 1.5 to 2.3 nm gap height is also present in the continuous part of the junction strand, small ion permeability can also be satisfied. The 1.5 nm radius pore does not significantly change Lp, whereas the continuous narrow slit provides a contribution to Lp that is comparable to, or in the case of the 2.3 nm slit greater than, the widely spaced 150 nm orifices. Thus, for the narrow slit the contribution to Lp from the orifices can be as low as 1.0×10−7 cm/s/cm H2O and it is also possible to satisfy the 2.5 fold increase in permeability that occurs when the matrix is enzymatically removed from the luminal side of the cleft, Adamson (1990). The likelihood of each of these cleft structures is discussed.
Lagrangian Formulation of the Equations of Motion for Elastic Mechanisms With Mutual Dependence Between Rigid Body and Elastic Motions: Part I—Element Level Equations
Authors: Nagarajan S. , Turcic David A.
Published: March 2008

Equations of motion are derived using Lagrange’s equation for elastic mechanism systems. The elastic links are modeled using the finite element method. Both rigid body degrees of freedom and the elastic degrees of freedom are considered as generalized coordinates in the derivation. Previous work in the area of analysis of general elastic mechanisms usually involve the assumption that the rigid body motion or the nominal motion of the system is unaffected by the elastic motion. The nonlinear differential equations of motion derived in this work do not make this assumption and thus allow for the rigid body motion and the elastic motion to influence each other. Also the equations obtained are in closed form for the entire mechanism system, in terms of a minimum number of variables, which are the rigid body and the elastic degrees of freedom. These equations represent a more realistic model of light-weight high-speed mechanisms, having closed and open loop multi degree of freedom chains, and geometrically complex elastic links.
Frequency Domain Design for Maximal Rejection of Persistent Bounded Disturbances
Authors: Jayasuriya S. , Franchek M. A.
Published: March 2008

A frequency domain methodology for synthesizing controllers for SISO systems under persistent bounded disturbances is presented. The control objective is to maximize the disturbance magnitude without violating prespecified state, control and bandwidth constraints. These constraints are treated explicitly in the design process. State and control constraints expressed in the time domain are first mapped into a set of equivalent frequency domain design specifications. The latter specifications define a set of frequency domain constraints on admissible loop transfer functions. These constraints are then displayed on a Nichols chart highlighting the dependency of the loop gains on phase and frequency. The final step in the process is to follow a loop shaping procedure to satisfy the frequency domain constraints. In the proposed methodology, the structure of the controller emerges naturally as a consequence of loop shaping and is not preconceived. The design procedure is semi-graphical and clearly demonstrates the design trade-offs at each frequency of interest. The effectiveness of the design method is illustrated by synthesizing a controller for a third order boiler-turbine set.
Linear Quadratic Optimal Control Via Fourier-Based State Parameterization
Authors: Yen V. , Nagurka M.
Published: March 2008

A method for determining the optimal control of unconstrained and linearly constrained linear dynamic systems with quadratic performance indices is presented. The method is based on a modified Fourier series approximation of each state variable that converts the linear quadratic (LQ) problem into a mathematical programming problem. In particular, it is shown that an unconstrained LQ problem can be cast as an unconstrained quadratic programming problem where the necessary condition of optimality is derived as a system of linear algebraic equations. Furthermore, it is shown that a linearly constrained LQ problem can be converted into a general quadratic programming problem. Simulation studies for constrained LQ systems, including a bang-bang control problem, demonstrate that the approach is accurate. The results also indicate that in solving high order unconstrained LQ problems the approach is computationally more efficient and robust than standard methods.
Active Damping Design of Flexible Structures Based on SISO and SIMO Noncollocated Sensor-Actuator Velocity Feedback
Authors: Zhang Qiang , Shelley S. , Allemang R. J.
Published: March 2008

An active damping design technique based on single input velocity feedback is presented in this paper. The stability conditions for each individual mode in SISO and SIMO velocity feedback are demonstrated. Since these stability conditions are derived using modal information, it is appropriate to incorporate this technique with the commonly used dynamic analysis techniques, such as experimental modal analysis and finite element analysis, for active damping design. Based on these stability conditions, two active damping design algorithms are proposed: 1) Constrained Least Squares Feedback Gain Computation, and 2) Optimal Feedback Gain Computation With Flexible Damping Factors. The first algorithm is a straightforward method to find the feedback vector for the given damping factors and the modal frequencies. The second algorithm is based on an optimization process which allows freedom in chosing the desired damping factors. The problem of locating the actuator and sensors is also discussed in this paper. The stability theory and active damping design technique are verified by an experimental example.
Backup Nutation Damping Strategy for the Galileo Spacecraft
Authors: Eke F. O. , Eke E. M.
Published: March 2008

This paper discusses the design of remedial measures that can be taken to achieve reasonable nutation damping of the Galileo spacecraft in the event of failure of its boom damper in flight. One scheme exploits the effects of payload motion on the nutational stability of a spinning spacecraft. This scheme demands that the spacecraft motion compensation algorithm be enabled with the scan platform bore sight pointed in a well chosen direction to produce rapid damping of spacecraft nutation. A second method suggested for nutation damping is a thruster-based open loop control algorithm, utilizing a pair of thrusters as actuators.
On Model Feedback Control for Robot Manipulators
Authors: Narikiyo T. , Izumi T.
Published: March 2008

Robot manipulators are highly coupled nonlinear systems and their motions are influenced by uncertain dynamics such as coulomb friction. These nonlinearities and uncertainties disturb the performance of control systems. In this paper, a control design methodolgy is proposed for the purpose of reducing the adverse effects of parameter uncertainties and disturbances. This control structure is similar to that of classical control. Unlike classical control, this control methodology accommodates multivariate control systems with uncertain dynamics and disturbances. The control design methodology is applied to a three-degrees-of-freedom directly driven robot. Simulation and experimental results demonstrate excellent robustness.
A Suboptimal Controller Design Method for the Energy Efficiency of a Load-Sensing Hydraulic Servo System
Authors: Kim S. D. , Cho H. S.
Published: March 2008

The dynamic characteristics of a load-sensing hydraulic servo system are complex and highly nonlinear and, furthermore, the stability is critically deteriorated compared with that of the conventional hydraulic servo systems. Another property of the systems is that the setting value of the pump pressure-compensator considerably affects energy efficiency as well as control performance of the system. These features significantly add complexity to the controller design of the load-sensing systems. To guarantee satisfactory control performance and energy efficiency of the system an effective controller design method, therefore, needs to be developed. This paper considers a suboptimal PID control for the velocity control problem of a loadsensing hydraulic servo system. To show the effectiveness of the controller a series of simulations and experiments were performed. Both results show that the proposed suboptimal controller can produce satisfactory response characteristics and yield an effective trade-off between control performance and energy efficiency of the system.
Stability Studies of Product-Type Nonlinear Systems
Authors: Miyagi Norio , Miyagi Hayao
Published: March 2008

This paper discusses the possibility of the existence of extended Lyapunov functions for stability studies in dynamical systems with product-type nonlinear feedback. Stability criteria for the system are given, which introduce extended Lyapunov functions. The method developed in the paper is applied to a van der Pol-type nonlinear system. The superiority of the function proposed is illustrated by numerical examples.
A Dynamic Analysis of a Nozzle-Flapper Valve With Integral Squeeze Film Damper
Authors: Burrows C. R. , Mu C. , Darling J.
Published: March 2008

An analysis of the dynamic response of a nozzle-flapper valve with integral squeeze film damper (SFD) is presented. An expression for oil film forces, including the effect of fluid inertia, has been derived using a first-order perturbation method. The nonlinear effect of flow control orifices is included in the simulation model. The effects of the squeeze film damper geometric coefficients have been examined and the flapper response to a step current input is modeled. The analysis also focuses on the relationships between output control pressure, input current, and supply pressure.