http://nova.newcastle.edu.au/vital/access/services/Feed ${session.getAttribute("locale")} 5 http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:13023 In this paper we introduce a new class of real-valued locally Lipschitz functions (that are similar in nature and definition to Valadier's saine functions), which we call arcwise essentially smooth, and we show that if g : R^m → R is arcwise essentially smooth on R^m and each function f_j : R^n → R, 1 ≤ j ≤ m, is strictly differentiable almost everywhere in Rⁿ, then g ○ f is strictly differentiable almost everywhere in Rⁿ, where f ≡ (f₁,f₂,...,f_m). We also show that all the semismooth and all the pseudoregular functions are arcwise essentially smooth. Thus, we provide a large and robust lattice algebra of Lipschitz functions whose generalized derivatives are well behaved. 2013-06-07T05:02:44.340Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:13022 In this paper we extend the notion of a Lebesgue-null set to a notion which is valid in any completely metrizable Abelian topological group. We then use this definition to introduce and study the class of essentially smooth functions. These are, roughly speaking, those Lipschitz functions which are smooth (in each direction) almost everywhere. 2013-06-07T05:02:01.247Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:13016 Multiple zeta values (MZVs, also called Euler sums or multiple harmonic series) are nested generalizations of the classical Riemann zeta function evaluated at integer values. The fact that an integral representation of MZVs obeys a shuffle product rule allows the possibility of a combinatorial approach to them. Using this approach we prove a longstanding conjecture of Don Zagier about MZVs with certain repeated arguments. We also prove a similar cyclic sum identity. Finally, we present extensive computational evidence supporting an infinite family of conjectured MZV identities that simultaneously generalize the Zagier identity. 2013-06-07T02:30:01.193Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:13015 We make a general study of the convergence properties of lattice sums, involving potentials, of the form occurring in mathematical chemistry and physics. Many specific examples are studied in detail. The prototype is Madelung's constant for NaCl: [formula could not be replicated]= -1.74756459···, presuming that one appropriately interprets the summation proccess. 2013-06-07T02:29:42.569Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:13014 We consider nonsmooth constrained optimization problems with semicontinuous and continuous data in Banach space and derive necessary conditions without constraint qualification in terms of smooth subderivatives and normal cones. These results, in different versions, are set in reflexive and smooth Banach spaces. 2013-06-07T02:29:12.299Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:12995 This paper deals with the assessment of the performance of reconstruction methods for computed tomography, including Filtered Back Projection and ‘entropy-like’ methods. For each of these methods, the influence of errors in the measured data on the reconstructed image is analyzed. A small perturbation of the data vector induces a perturbation of the reconstructed object which can be computed by means of the sensitivity matrix. Using appropriate matrix computation techniques, an upper bound on the size of the reconstruction error is determined, as well as the pattern of noise in the sinogram that will result in the largest reconstruction error. Simulations will illustrate our analysis and demonstrate its utility in the interpretation of computed images and in the selection of reconstruction parameters. 2013-06-06T06:20:01.594Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:12842 Given a schedule of flight legs to be flown by an airline, the fleet assignment problem is to determine the minimum cost assignment of flights to aircraft types, called fleets, such that each scheduled flight is assigned to exactly one fleet, and the resulting assignment is feasible to fly given a limited number of aircraft in each fleet. Then the airline must determine a sequence of flights, or routes, to be flown by individual aircraft such that assigned flights are included in exactly one route, and all aircraft can be maintained as necessary. This is referred to as the aircraft routing problem. In this paper, we present a single model and solution approach to solve simultaneously the fleet assignment and aircraft routing problems. Our approach is robust in that it can capture costs associated with aircraft connections and complicating constraints such as maintenance requirements. By setting the number of fleets to one, our approach can be used to solve the aircraft routing problem alone. We show how to extend our model and solution approach to solve aircraft routing problems with additional constraints requiring equal aircraft utilization. With data provided by airlines, we provide computational results for the combined fleet assignment and aircraft routing problems without equal utilization requirements and for aircraft routing problems requiring equal aircraft utilization. 2013-05-02T01:43:41.956Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2144 This paper develops exact, computable formulas for the frequency gain and L₂-induced norm of the sensitivity operator in a sampled-data control system. With sampled data, we refer to a system that combines both continuous-time and discrete time signals, which is studied in continuous time. The expressions are obtained using lifting techniques in the frequency domain and have application in performance and stability robustness analysis taking into account full intersample information. 2013-02-26T23:10:12.556Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:11951 Improvement in life expectancy in Western populations is coupled in part to the initial fall in stroke mortality in the late 1950's and the later fall in coronary artery disease mortality of the l970's. It is generally accepted that in recent years antihypertensive, thrombolytic, and antiarrhythmic therapy plus improvements in acute care management and the use of β-adrenergic blocking agents has accelerated the decline in mortality. These findings, however, are challenged by the rising rate of hospitalisation for acute myocardial infarction at all ages in Western countries. 2012-12-13T00:19:24.584Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:12097 Unemployment remains anchored above eight percent while average unemployment duration is around 51 weeks and the youth unemployment rate is above 20 per cent. The Coalition's policy manifesto for the 1996 federal election emphasised the seriousness of the unemployment problem; indeed, it gave priority to reducing the unemployment rate, especially the relatively high youth rate, and to the generation of 'real' jobs. Over the past two and a half years the Coalition Government has put in place a series of supply-side reforms that are justified on the basis of their contribution towards reducing unemployment. Industrial relations reforms, fiscal consolidation, the privatisation of the Commonwealth Employment Service, the abolition and consolidation of labour market programs and the privatisation of public sector business enterprises are all part of the unemployment reduction program. To date, the success of this program has been limited, job creation remains low, and 'real' jobs remain scarce since net job growth is largely located in part-time and/or casual employment arrangements. 2012-11-22T03:38:05.670Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:11791 Background: The arterial baroreflex acts to maintain arterial pressure in the face of an orthostatic challenge. The high +Gz loads experienced by fighter pilots represent an extreme form of orthostatic challenge. G-induced loss of consciousness (G-LOC) represents a failure of the baroreflex system to maintain the appropriate level of cerebral perfusion. The anecdotal experience of fighter pilots is that their cardiovascular systems adapt to frequent exposure to high +Gz levels. Hypothesis: The purpose of this study was to demonstrate that the baroreflex-mediated cardiovascular response of a group of 8 fighter pilots to a mild accelerative stimulus differs from that of a group of 12 non-pilots. Methods: Arterial pressures and heart rate responses to rapid head-up tilting to +75 degrees were compared between the two groups. Five variables were examined: systolic, diastolic, mean arterial and pulse pressures, and heart rate. Results: The cardiovascular responses of the groups were fundamentally different. In response to tilt, the non-pilots showed little change in systolic and mean arterial pressures, diastolic pressure increased slightly and pulse pressure decreased significantly. In the pilot group, however, significant increases were observed in systolic, diastolic and mean arterial pressures (p < 0.05), whereas pulse pressure did not change. Between groups there were significant differences observed in terms of arterial pressures (p < 0.05), but not heart rate. Conclusions: The baroreflex of a fighter pilot is capable of adapting to +Gz, becoming a more sensitive and effective BP control system as a result. This adaptation affords the pilot greater protection against G-LOC. 2012-10-22T22:24:46.285Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:11056 A popular colloquialism expressing connotations of hidden family secrets, "skeletons in the closet", had a particular resonance for me as I came to the end of researching my postdoctoral history thesis on relationships between Aboriginal and white women under the NSW Aborigines Protection Board "apprenticeship" policy. Based on a reconstructed life-narrative of my greatgrandmother, a white woman, it involved not only my own family history, but also the personal histories of four Aboriginal women connected with her. The following discussion of some of the issues that arose for me in the research, writing and submission process is derived from a talk I gave at the 1998 Australian Historical Association conference under the same title. After submitting my abstract for this conference, I came across a article published last year by Hetti Perkins, on Aboriginal artist Judy Watson, entitled "Our skeletons in your closets". Unlike Perkins, however, who was clearly talking about the symbolic reclamation of Aboriginal traces, I was deliberately ambiguouS in not identifying Whose skeletons are cloistered in our closets; what emerged in my work were the enmeshed skeletal remains of histories of both white and Aboriginal people, and also the shameful secrets of the government bureaucracy that engineered and oversaw the placement of Aboriginal girls into white suburban homes. 2012-07-06T05:00:07.370Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:10957 Distinctions are made between global and specific, personal and social, and trait and state self-esteem, and these are used to structure a review of over 40 studies concerning social identity theory's hypothesis that (a) intergroup discrimination elevates self-esteem and (b) low self-esteem motivates discrimination. It is observed that researchers have tended to employ measures of global personal trait self-esteem in their investigations of this self-esteem hypothesis, and it is argued that measures of specific social state self-esteem are more consistent with social identity theory's assumptions. Although no convincing evidence is found for the self-esteem hypothesis in its full and unqualified form, it is argued that this is due to a lack of specificity in its formulation and it is suggested that a more qualified and specific version of the hypothesis may be more appropriate. 2012-06-22T06:34:13.641Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:10894 Verification and validation are two very important steps in simulation modeling. Consequently, they are under constant review and examination from many different perspectives. Researchers have identified several modes of conducting verification and validation and proposed taxonomies for techniques used in their execution. This paper visits the issues in the light of a case study being carried out specifically in the health sector. The paper argues that the health sector is characterized by a level of complexity in handling “resources” (as understood in simulation modeling) which is not frequently found in the manufacturing sector. This complexity makes validation and verification of simulation models a difficult and challenging task. While the earlier articulation of modes of verification and validation and their taxonomy are generally helpful, there is still some work which could be fruitfully undertaken in understanding various situations and, especially, the perspectives which the “end-users” or clients bring to bear upon any modeling exercise. 2012-06-13T00:36:25.065Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2669 This paper investigates the use of general bases with fixed poles for the purposes of robust estimation. These bases, which generalise the common FIR, Laguerre and two--parameter Kautz ones, are shown to be fundamental in the disc algebra provided a very mild condition on the choice of poles is satisfied. It is also shown, that by using a min--max criterion, these bases lead to robust estimators for which error bounds in different norms can be explicitly quantified. The key idea facilitating this analysis is to re--parameterise the model structures into new ones with equivalent fixed poles, but for which the basis functions are orthonormal in H₂(D). 2012-05-28T22:58:10.141Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2668 In this paper, we provide a H ∞ norm lower bound on the worst-case identification error of least-squares estimation when using FIR model structures. This bound increases as a logarithmic function of model complexity and is valid for a wide class of inputs characterized as being quasi-stationary with covariance function falling off sufficiently quickly. 2012-05-28T22:56:21.826Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2743 This paper examines the problem of system identification from frequency response data. Recent approaches to this problem, known collectively as "Estimation in H∞", involve deterministic descriptions of noise corruptions to the data. In order to provide "worst-case" convergence with respect to these deterministic noise descriptions, non-linear in the data algorithms are required. In contrast, this paper examines "worst-case" estimation in H infinity when the disturbances are subject to mild stochastic assumptions and linear in the data algorithms are employed. Issues of convergence, error bounds, and model order selection are considered. 2012-05-28T22:54:28.852Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2010 A new approach to modelling response time is proposed, based on the activation dynamics of simplified neural units. The proposed neuromorphic decision units are dissipative and have bounded activation, as do real neurons. A decision is made either when the unit's activation exceeds a threshold or when it converges, using a criterion based on the derivative of activation. First, the relationship between varieties of neuromorphic and sequential sampling models is reviewed. Mathematical and simulation results are presented both for deterministic and random versions of the neuromorphic units. These results are used to highlight strengths and weaknesses of this new approach to dynamic models of decision making. 2012-05-28T05:04:57.537Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:10726 Discusses feminism, maternalism, and the campaign for Aboriginal citizenship in New South Wales, Australia in the late 1930s. Details on the relationship between Pearl Gibbs, a leader of the Aborigines Progressive Association, and a white activist, Joan Strack; Complexity of Strack's position as an activist for Aboriginal citizenship. 2012-05-16T04:33:48.396Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2808 Induction magnetometer data recorded at three closely spaced sites (~120 Km) in Antarctica (mlat ~−75°) have been examined for ionospheric signatures of the cusp/cleft region of the magnetosphere. Crossphase analysis of the 1-10 mHz band, using pure-state filtering techniques reveal diurnally varying field line resonances embedded in the spectra, while interstation phase lag measurements indicate azimuthal propagation of waves away from local magnetic noon. Using the T89 external field model crossphase measurements are put in the context of diurnally changing field line topology due to compression at the subsolar region and stretching along the dawn and dusk flanks. On six of the eight days of this study we have identify a consistent two dimensional phase pattern projected in the dayside ionosphere, indicating closed field lines thread these sites during periods of low to moderate geomagnetic activity (Kp<3). 2012-03-12T07:22:24.080Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:6548 Mouse sperm-egg fusion was examined using twophoton and confocal microscopy. A delay of several minutes occurred between the first observable event of fusion (which was the diffusion of Ca²⁺-sensitive dyes from egg into sperm)and any change in egg cytoplasmic Ca²⁺. When indo-1 dextran was used to obtain ratiometric two-photon images,there was no detectable local increase in egg cytoplasmic Ca²⁺ near the site of sperm fusion. However, the sperm underwent a Ca²⁺ transient which appeared to be coincident with the egg cytoplasm Ca²⁺ transient, which suggested that there was a high permeability pathway for Ca²⁺ between egg and sperm. To exclude this pathway from providing trigger Ca²⁺ for the egg transient, we reduced bathing (Ca²⁺] to approx. 18 μM and 13nM (with EGTA). In these conditions the first egg Ca²⁺ transient was not prevented, which makes an obligatory role for extracellular Ca²⁺ in the initiation of the egg Ca²⁺ transient unlikely. Both FITC-albumin (70 kDa) and 10 kDa dextran-linked Ca²⁺ indicators were able to diffuse into the sperm from the egg. In addition, phycoerythrin (240 kDa)rapidly diffused into the sperm shortly after fusion (but before any changes in Ca²⁺ occurred). This suggests that the ‘pore(s)’ that form during sperm-egg fusion must be at least 8 nm in diameter. These data are compatible with the idea that a diffusible sperm protein could trigger the observed changes in intracellular Ca²⁺ in the egg, but do not exclude the possibility that other second messengers are generated during sperm-egg fusion. 2012-01-30T04:07:35.629Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:683 In maintaining power system stability; especially that of large interconnected systems, in the face of large disturbances it is desirable to have a non-linear control technique that is simple and inexpensive to implement. This thesis presents a non-linear control technique which relies on angle measurements taken at strategic points in the power system with the aid of the G.P.S. ( Global Positioning System ) timing signal. A method for estimating these bus angles which is faster than previous methods is developed as well as a technique for choosing the locations of these transducers. This transducer placement algorithm aims to place transducers at locations whose bus voltage response to the less well damped inter-area modes is maximised and whose response to the better damped local modes is minimised. Since the control techniques are based on aggregated classical models of coherent generators it is important to be able to estimate the internal voltages of these aggregate machines. The placement algorithm ensures maximally precise angle estimates in the presence of noise by minimising the condition number of the observation matrix relating transducer bus voltages to internal aggregated machine voltages. The non-linear control techniques presented rely on an energy function developed in this thesis which is based on the physical circuit energy of the system. One technique; the Direct Energy technique looks at maximising the negativity of the time rate of change of the energy function, assuming that the energy function is positive during the time frame of interest. It is shown that should the number of controllers be less than the number of modes, excluding the centre of area mode, then sustained oscillations appear which will only be damped by the natural damping of the system. This may be overcome by using techniques which rely on reducing the entire system energy over the time frame of interest. These so-called Lookahead techniques can rely on higher order time derivatives of the energy function or on co-states, the latter being the principal focus of this thesis. The Lookahead control technique developed is based on co-states which are estimated by the using the solution to the time independent Ricatti equation for a LQ model of the system. It is shown to produce good damping in a number of case studies. Furthermore it is shown to perform well in the presence of both static and dynamic load models. Also it is shown that the path dependent terms introduce some ambiguity as to whether or not the system will converge to a stable equilibrium point. It is shown that it is possible to put a bound on the region to which the power system can be assured to converge. Furthermore the addition of the above-mentioned control strategies has the effect of overcoming the effect of the path dependent terms and, should the control action be strong enough, completely swamping them and ensuring system convergence to a stable operating point. In any case the energy function could be directly monitored since all the data needed is being collected anyway for control purposes. 2011-12-20T23:20:11.075Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2801 Research Doctorate - Doctor of Philosophy (PhD) 2011-12-19T23:00:02.485Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:9635 Popular Aboriginal legendary tales have been one of the most significant ways in which Aboriginality has been constructed in Australia, but they have not received much attention prior to this paper. Beginning with missionary accounts of Baiame, a deity associated with Gamilaraay (Kamilaroi) and Wiradhuri (Wiradjuri) speaking peoples of colonial Australia, the author examines the way in which the theme of the Great Spirit or Baiame is developed in popular mythology. The focus is placed on two key writers: K. Langloh Parker and David Unaipon. It is argued that the popular discourse of “The Land of Byamee” reflected the political constraints of the assimilation era. 2011-12-07T02:40:06.982Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:9625 Ethical thinking can be done in a variety of ways and draw quite different conclusions. People of upright intention disagree about the 'moral ought' associated with particular issues, and difference is evident along several lines', .;. including, most importantly, those of culture. Taylor contrasts the values positions of ancient and modern cultures, while King spoke eloquently of the challenge of drawing the various cultures of contemporary USA together in a common push for justice. Charlesworth suggests that, beyond the most primary values related to autonomy and justice, it is impossible for the modern multicultural society to come to a consensus on most of the practical values that guide everyday living. These are important issues for teachers, especially in multicultural settings. While it is beyond the scope of this raper to provide a full analysis of cultural difference in values perspectives, it may be helpful to identify a number of clearly different ethical cultures which, history shows, have managed to survive and thrive even in the same society. Here I will draw deliberately on the most prominent ethical cultures of the most important ancient society for those searching out the roots of Western thought, namely, the society of ancient Greece. In this sense, the analysis is limited to a Western perspective. The exemplar nonetheless underlines the point that different ethical cultures have existed and competed throughout recorded history, and have done so even within apparently homogeneous societies. In other words, multi-ethnicity is only one feature of multi-culture, albeit a particularly defining one in our own time. 2011-12-07T01:10:05.601Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2327 A fundamental limitation exists in the achievable tracking performance of non-right-invertible systems. This limitation manifests itself in the cheap control tracking cost, which we show to be a function of the plant non-minimum phase zeros and of the variation with frequency of the plant direction. The cheap control tracking cost is further connected with an integral relation that constrains the performance of any stable closed-loop system where the plant has a single input and two outputs. 2011-10-20T03:10:02.322Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:6600 Activation during fertilization in all animal oocytes is mediated by Ca²⁺ changes. In mammals, a series of Ca²⁺ oscillations is observed lasting a number of hours (Miyazaki et al., 1993; Swann and Ozil, 1994; Schultz and Kopf, 1995) which, when blocked, inhibits all the events of oocyte activation. There is current interest (and certainly much argument) as to the relative importance of the two main hypotheses which explain how the spermatozoa cause Ca²⁺ oscillations in the oocyte. The first is that spermatozoa act via plasma membrane receptors to generate the Ca²⁺ mobilizing messenger inositol 1,4,5-trisphosphate (InsP₃) (Foltz and Shilling, 1993; Shilling et al. 1994). The alternative hypothesis suggests that the spermatozoa introduce a soluble and presumably cytosolic factor that diffuses into oocytes after the sperm-oocyte membrane fusion (Dale et al., 1985; Stice and Robl, 1990; Swann, 1990; Stricker, 1997; Fissore et al., 1998). This is the so called 'sperm factor' hypothesis that we and others have supported for a number of years. Here we present a history of the sperm factor model, which may offer some insight into the current status of the hypothesis. 2010-08-12T03:10:01.204Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:6595 At fertilization, the spermatozoon is generally held to generate two important second messengers, inositol trisphosphate and diacylglycerol. A similar situation arises when these signalling molecules are generated after a hormone binds to its plasma membrane receptor. This signalling mechanism releases intracellular Ca²⁺ which causes cortical granule release and initiates meiotic resumption. This review will examine the role played at fertilization by protein kinase C which is a primary target of diacylglycerol. The pharmacological agents phorbol esters, which mimic the action of diacylglycerol, when added to mammalian oocytes induce cortical granule release and may cause meiotic resumption. However, the originally accepted mechanism of fertilization is now questioned with the recent finding of a soluble sperm Ca²⁺-releasing factor expelled directly into the oocyte cytoplasm, bypassing any membrane receptor. Therefore, it is timely to re-evaluate the role played by protein kinase C at fertilization in light of a mechanism that may produce Ca²⁺ without producing diacylglycerol concomitantly. This article will examine the evidence implicating activation of protein kinase C in Ca²⁺ oscillations, cortical granule release and meiotic resumption. It will contend that pharmacological studies relying on the specificity of phorbol esters and other agonists, as well as inhibitors of protein kinase C, have produced conflicting interpretations of the role of this kinase at fertilization. 2010-07-29T22:20:12.296Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:6594 At fertilization the union of the sperm and egg has two important functions: it brings together their genetic components and it triggers embryonic development. It is oNen assumed that only the genetic component has an important part to play in further development. In the following review it is argued, on the basis of recent findings, that in disregarding the initial trigger for development, a rise in cytoplasmic Ca²⁺, an important factor in the control of embryonic development is being ignored. The review will concentrate on mammalian eggs due to the very characteristic Ca²⁺ changes which constitute the trigger for egg activation, and so embryonic development. Mammalian eggs show low.frequency Ca²⁺ oscillations over a period of several hours. It will be argued that a novel mechanism of Ca²⁺ release is employed by the sperm at fertilization and such Ca²⁺ changes have a role in subsequent development of the embryo in addition to the initial events of egg activation. For the purposes of this review the female gamete is defined as an 'egg' when it is at a stage that it is normally fertilized, in contrast to an 'oocyte' when it is at an immature stage of maturation and would not normally be fertilized. For all the species discussed here only in the sea urchin is the female gamete correctly termed an egg, having completed all the stages of meiosis. 2010-07-29T22:10:05.608Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:6582 Injection of sperm extracts triggers Ca²⁺ oscillations in mammalian eggs similar to those seen at fertilisation. Here, we show that addition of sperm extracts to sea urchin egg homogenates causes Ca²⁺ release and inositol 1,4,5-trisphosphate (InsP₃) production. Furthermore depleting homogenates of phosphatidylinositol lipids using a phosphatidylinositol-specific phospholipase C blocked the sperm extract from causing InsP₃ production and a Ca²⁺ rise. A response could be recovered by the addition of phosphatidylinositol 4,5-bisphosphate to either sperm extracts or egg homogenates. These data indicate that sperm extracts contain an InsP₃-generating phospholipase C which may play a role in Ca²⁺ release at fertilisation. 2010-07-28T06:00:02.990Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2521 An automated marking pilot scheme conducted at the University of Newcastle in 1997 has been extended in collaboration with Deakin University to include distance learners. The work is being carried out under an Australian National Training Grant for 1998-99. This paper describes the security and integrity strategies we adopt for automated assessment, and discuss the merits of authentication strategies for assessment processes in the on-campus and distance learning scenarios. 2010-06-10T04:15:54.586Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2924 This article examines some of the issues associated with the development of primary Studies of Society and Environment curriculum, with particular reference to primary curricular issues in New South Wales, and positing some future directions for this subject. 2010-04-27T07:00:21.462Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2810 Decay-accelerating factor (DAF) mediates cellular attachment for many human picornaviruses. In most cases, viral binding to DAF is itself insufficient to permit cell infectivity, with a second, functional internalization receptor being required to facilitate this process. Previously, we postulated that the role of DAF in enterovirus cell infection is as a sequestration receptor, maintaining a reservoir of bound virus in an infectious state, awaiting interaction with functional internalization receptors. Many of these functional receptors possess the capacity to induce relatively rapid changes in capsid conformations, resulting in the formation of altered particles (A-type particles). In this report, we show that antibody-cross-linked DAF, in contrast to endogenous surface-expressed forms, can act as a functional virus receptor to mediate coxsackie A21 virus (CAV21) lytic cell infection. In contrast to the situation with ICAM-1-mediated CAV21 infection, in which high levels of A-type particles are formed, cross-linked DAF-induced CAV21 replication occurs in the absence of detectable A-particle formation. 2010-04-27T07:00:04.594Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2878 This paper presents details of the method used to determine the Thornwaite Index which is a measure of aridity. The index is then used to provide improved estimates of the depth of design moisture needed for estimating reactive clay movement in the Hunter Valley. Importantly, the method described is consistent wit the methodology and philosophy of AS 2870. 2010-04-27T06:57:15.316Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2328 The main contribution of this paper is a number of structure dependent stability results applicable to a class of hybrid systems modelled by discrete automata. Our main results are formulated as two stability theorems giving necessary and sufficient conditions for global stability of synchronous and asynchronous piecewise linear hybrid systems. These theorems effectively reduce the hybrid systems stability analysis problem to analysis of stability of a certain class of linear time varying systems. 2010-04-27T06:50:11.237Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2501 In this paper, we investigate the implications for robust sampled-data feedback design of minimum phase sampling zeros appearing in the transfer function of discrete-time plants. Such zeros may be obtained by zero-order hold (ZOH) sampling of continuous-time models having relative degree two or greater. In particular, we address the robustness of sampled-data control systems to multiplicative uncertainty in the model of the continuous-time plant. We argue that lightly damped controller poles, which may arise from attempting to cancel, or almost cancel, sampling zeros of the discretized plant are likely to introduce peaks into the fundamental complementary sensitivity function near the Nyquist frequency. This in turn makes the satisfaction of necessary conditions for robust stability difficult for all but the most modest amounts of modeling uncertainty in the continuous-time plant. Some H2082₂- and H∞-optimal discrete-time and sampled data designs may lead to (near-) cancellation, and we therefore argue that their suitability is restricted 2010-04-27T06:49:59.975Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2126 This paper analyses eduactional forces in TAFE in relation to curriculum issues linked to wider social and cultural contexts arising from a ANTA-funded pproject into the teaching and learning needs of special interest groups. In particular, this paper attempts to explain the educational process in TAFE and motivations for changing teaching and learning strategies to more effectively meet the needs of special interest groups. the aim is to present a synthesis of student and teacher perspectives that provides a basis for moving between practice and policy in VET. In our tender to the ANTA Research Advisory Council, the project team outlined a number of strategies to be adopted in order to achieve uts aim to identify the teaching and learning needs of special interest groups. One objective was to assist in the formulation of strategies for further development of approprite curriculum in VET in Australia in a way that assisted closer alignment between teaching practice and preferred learning styles, the course areas studied were Carpentry and Joinery, Child Care, Tourism and Hospitality and Business Studies. 2010-04-27T06:43:44.905Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2118 2010-04-27T06:43:40.034Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2105 2010-04-27T06:43:27.133Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:1149 We consider the problem of approximating the global minimum of a general quadratic pro-gram (QP) with n variables subject to m ellipsoidal constraints. 2010-04-27T06:38:06.327Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2647 In this paper we describe the current state and future direction of research which has already verified the performance of the Grasshopper persistent operating system compared to Unix executing on the same hardware. This research is now drawing on techniques described in the large body of database literature to improve the efficiency of database operations when utilising features of an underlying persistent store. 2010-04-27T06:32:29.004Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2702 This paper presents a comprehensive picture of the mapping of structural properties associated with general linear multivariable systems under bilinear transformation. While the mapping of poles of linear multivariable systems under such a transformation is well known, the question of how the structural invariant properties of a given system are mapped remains unanswered. This paper addresses this question. More specifically, we investigate how the finite and infinite zero structures, as well as invertibility structures, of a general continuous-time (discrete-time) linear time-invariant multivariable system are mapped to those of its discrete-time (continuous-time) counterpart under the bilinear (inverse bilinear) transformation. We demonstrate that the structural invariant indices lists I₂ and I₃ of Morse remain invariant under the bilinear transformation, while the structural invariant indices lists I₁ and I₄ of Morse are, in general, changed. 2010-04-27T06:30:31.321Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2703 In the original paper by Tesfaye and Tomizuka (ibid., vol.40, p.743-7, 1995), an asymptotic analysis was used to address the zero structure of discretized continuous-time systems expressed in the Euler (or forward difference) operator. The method was developed for application to multivariable control systems. The authors state that the analysis is flawed, so that a theorem is true as stated only when the continuous time relative degree is equal to two. They indicate how the analysis may be rectified. Tesfaye and Tomizuka acknowledge the error and the correctness of the result in this paper. 2010-04-27T06:30:18.967Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:851 Several models have emerged for describing 1/fγ noise processes. Based on these, various techniques for estimating the properties of such processes have been developed. This paper provides theoretical analysis of a new wavelet-based approach which has the advantages of having low computational complexity and being able to handle the case where the 1/fγ noise might be embedded in a further white-noise process. However, the analysis conducted here shows that these advantages are balanced by the fact that the wavelet-based scheme is only consistent for spectral exponents γ in the range γ∈(0, 1). This is in contradiction to the results suggested in previous empirical studies. When γ∈(0, 1) this paper also establishes that wavelet-based maximum-likelihood methods are asymptotically Gaussian and efficient. Finally, the asymptotic rate of mean-square convergence of the parameter estimates is established and is shown to slow as γ approaches one. Combined with a survey of non-wavelet-based methods, these new results give a perspective on the various tradeoffs to be considered when modeling and estimating 1/fγ noise processes. 2010-04-27T06:22:05.733Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2040 2010-04-27T06:21:11.313Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2805 The recent decline and extinction of amphibian species is a worldwide phenomenon without an identified cause or solution. Assisted reproductive technologies, including sperm cryopreservation, are required to manage endangered amphibian species and preserve their genetic diversity. This study on the Anuran amphibian (Bufo marinus) was undertaken to determine the feasibility of cryopreservation of amphibian sperm. Sperm suspensions for cryopreservation were prepared by macerating testes in cryoprotective additives of 10% (w/v) sucrose or 10% (w/v) sucrose containing either 10, 15, or 20% (v/v) glycerol or 10, 15, or 20% (v/v) dimethyl sulfoxide (Me₂SO). Suspensions were then cooled to −85°C using a controlled rate cooler, stored in LN₂, and thawed in air. The motility and fertilization rate of cryopreserved suspensions and unfrozen control suspensions in Simplified Amphibian Ringer were compared. Sucrose alone had no cryoprotective effect. All other treatments showed varying degrees of recovery of motility and fertilizing capacity. High rates of recovery of motility and fertilizing capacity were observed with 15% Me₂SO (68.9 ± 3.8 and 60.5 ± 4.7%) and 20% glycerol (58.0 ± 5.9 and 81.4 ± 4.3%), respectively. Motility and fertilization rates were similar with Me₂SO but diverged with glycerol as cryoprotectant. The data demonstrate the feasibility of using sperm cryopreservation with amphibian species. 2010-04-27T06:18:49.547Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2806 A two-part study was undertaken with students enrolled in a first year university subject (development psychology). The theory of achievement goals formed the framework for the study. The first part of the study was designed to delineate students' perceptions of the motivational 'climate' of the subject and to relate these perceptions to other theoretically relevant variables, including reported use of effective learning strategies and a positive approach to learning. To do this, students completed two questionnaires, one half-way through the year and another at the end of the year. The second part of the study was an examination of students' reactions to one aspect of the subject (the major assignment) that was structured specifically to enhance students' mastery goal orientation. Aspects addressed included the nature of the task, evaluation procedures, amount of control given to students, and the option of working collaboratively or independently. In addition to questionnaire data, 54 students were interviewed about completing the major assignment to ascertain whether or not their reactions reflected those predicted by achievement goal theory. 2010-04-27T06:18:49.526Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2802 This paper outlines a causal reasoning chain approach of a Knowledge Based System of architecture for medical applications. It is examined within the context of a fetal health decision support system module to provide diagnosis of pregnancy-induced hypertension, or pre-eclampsia. a simplified example is presented to illustrate our approach. 2010-04-27T06:18:46.976Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2807 Magnetic fluctuations in the 22-100 millihertz (Pc3) band are a consistent indicator of the presence of the cusp in the overhead ionosphere at high latitudes. Correlation of the signals from a variety of instruments have shown that the sources of these pulsations are local (ionospheric) rather than distant (magnetospheric) [Engebretson et al., 1990]. Modulated electron precipitation is presumed to be the source of the fluctuations through the modulations in ionospheric conductivity that they produce. Olson and Szuberla [1997] used data from a pair of cusp stations to deduce the scale size of the precipitating beams using a simple model in which the beams were assumed to have circular cross section. They obtained an upper bound for the coherence length of the order of 200 km. In this paper we extend the analysis of Olson and Szuberla by incorporating data from the Magnetometer Array for Cusp and Cleft Studies (MACCS) magnetometer array and the Australian ANARE antarctic sites to give a broader range of station separations. Using a statistical approach we computed the cumulative distribution function of the interstation coherence and from that distribution we established a measure of coherence, CL . The result of this analysis is a coherence that diminishes with inter-station distance as CL ≈ 1.4 exp(−S/250) where S is the station separation in km. When this result is interpreted in the context of the simple model mentioned above we find a coherence length of 140 - 180km. 2010-04-27T06:18:44.517Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2809 The substance of this article is a narrative about a man considered mad in a highland Papua New Guinea society, and about his interaction with his com munity and with an anthropologist who tried unsuccessfully to change the com munity's negative attitude towards him. It is argued that his madness was socially constructed, and cannot be adequately explained using a psychiatric paradigm, even if the psychiatric approach were modified to accommodate cultural differ ence or notions of culture-bound syndromes. It is further argued that the social construction, a dialectic of group and individual praxis, can be analytically con textualized in a moral imperative grounded in the community's kin-ordered mode of production, and can be interpreted as a communal exercise in moral iconography. 2010-04-27T06:18:42.677Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2927 Previous studies by the authors have documented systematic changes in the speech and signing of teachers of the deaf using speech and sign together in Simultaneous Communication (SimCom; Hyde & Power, 1991; Leigh & Hyde, 1994). It appears that well trained and motivated teachers can find SimCom not an "impossible task" (as claimed by Strong & Charlson" 1987) and can accurately sign what they are simultaneously saying (see also Mayer & Lowenbraun, 1990). It also appears that there are systematic changes in the accuracy of signing under SimCom conditions with school level; high school teachers generally being less accurate than primary school ones in reproducing on their hands what they are sayrng (Leigh, 1993). Characteristic changes take place in the speech of teachers under SimCom conditions (Hyde & Power, 1991; Hyde, Power & Leigb 1995). Speech and sign rate is slower than speech alone, with the major contributors to this slowing being elongated intra-sentence pauses and elongation of vowels within words. However, it was also found that slowed speech under the SimCom condition was rated by adult deaf listeners as "more understandable" than speech to "Oral-Only" students and hearing students (Ilyde, Power & Leigh, 1995). The present study expands the report of Hyde, Power & Leigh to examine aspects of the lexical and syntactic characteristics of the language of teachers of the deaf under three simulated conditions of teachers speaking to a group of children using SimCom or Oral-Only methods and to a group of hearing children. Such an analysis is of interest because, for example, it has been argued by some critics of SimCom that teachers use simplified lexicons and syntax under this condition when compared with Oral-Only input, thus limiting the opportunities deaf children learning under SimCom have to extend their language. Some commentators have also argued that the kind of lexical and syntactic changes found in the speech of teachers to Oral-Only students also restricts their language development. 2010-04-27T06:18:33.653Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2575 This paper is a tutorial discussion of the current difficulties being experienced with the performance of armored face conveyor (AFC) drive systems, as used in longwall mining. It presents the traditional approaches to the design of the drive system and highlights the inadequacies. The final part of the paper presents a possible solution approach using variable-speed drive systems, emphasizing the advantages of this approach. The paper is significant, in that it discusses, in one document, a number of problems related to the operation of longwall AFCs. Furthermore, it presents a solution path for these problems. 2010-04-27T06:18:27.057Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2576 This paper investigates a new control approach for longwall armored face conveyors (AFCs) using variable-speed drives (VSDs). Traditionally, AFCs have used fixed-speed or two-speed motors, with various mechanical solutions employed to try to solve the problems that this causes. The VSD approach to the control problem promises to solve all the significant problems associated with the control of AFCs. This paper presents control algorithms developed for a VSD-based AFC drive system and demonstrate potential performance via computer simulation 2010-04-27T06:18:27.027Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2581 A new high-performance sensorless speed vector controller that implements the maximum torque per ampere control strategy for the inverter-driven synchronous reluctance machine is presented in this paper. It is based on a parameter-dependent technique for online estimation of rotor position and angular velocity at the control rate. The current ripple principle is used to estimate position. The estimates are fed to a conventional closed-loop observer to predict the new position and angular velocity. The very high accuracy of the sensorless control algorithm at both low and high speeds is confirmed by experimental results. 2010-04-27T06:18:01.197Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2585 Despite the widespread adoption of the total communication philosophy and its most frequent application in simultaneous communication, concerns have emerged about the relative effectiveness of its practices from both receptive and productive perspectives. 2010-04-27T06:17:58.868Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2610 This paper is concerned with a class of continuous time uncertain systems which satisfy a certain Integral Quadratic Constraint. The problems of robust filtering, robust prediction, and robust smoothing for such systems are defined, and nonconservative solutions are given in terms of Riccati differential equations. This paper also addresses a problem of robust observability for this class of uncertain systems. 2010-04-27T06:14:11.984Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2071 2010-04-27T06:08:56.770Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2075 2010-04-27T06:08:40.727Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2073 2010-04-27T06:08:38.671Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2072 During a recent stay working at the Centre for Policy Studies at King's College London I had the opportunity to examine close at hand and in depth the education policies of all the major parties contesting the 1997 election in the UK. This paper will outline key differences and similarities between the competing political manifestos. More importantly, it will provide a commentary on their reception and on their potential now that the government has been decided. The extent to which these policies might foreshadow educational developments in Australia will be addressed. Finally, the implications for educational policy research in what may or may not be a "new time" will be drawn out for discussion. 2010-04-27T06:08:38.506Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2796 Sydney rock oysters, Saccostrea commercialis, were deployed for a 3-month period at sewage-disturbed and control marine locations in the Hunter Region, New South Wales, Australia. After this period, the oysters were retrieved and the gills dissected and extracted for analysis of the saponified lipid components (including fatty acids and sterols), using gas chromatography-mass spectrometry (gc-ms). Multivariate analysis (discriminant function) of the gc-ms lipid profiles indicated that the lipid homeostasis in oysters from the sewage locations was significantly different compared with that observed in oysters from control locations (p < 0.0001). The primary factor discriminating between sewage and control locations was the level of β-sitosterol, a plant sterol derived from domestic sewage and marine algae. The results indicate that gill lipid metabolism differentially alters in response to deployment of oysters into either sewage-contaminated or control locations. This method of analysis provides a sensitive measure for the biological impact of composite waste cocktails on strategically located marker organisms in affected environments. 2010-04-27T06:04:33.721Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2794 OBJECTIVE: We sought to identify the psychosocial characteristics of high earthquake exposure subjects that were associated with the development of post-disaster morbidity and with recovery. METHOD: Data reported are from 515 participants in a longitudinal study of the psychosocial effects of the 1989 Newcastle (Australia) earthquake. Subjects were allocated to three subgroups (low morbidity; recovered; and persistent morbidity) on the basis of their Impact of Event Scale scores across the four phases of the study. Differences between these subgroups were examined on a broad range of variables. RESULTS: Several background, dispositional, coping style and exposure-related factors characterised those who developed psychological morbidity, only a small subset of which differentiated between those who recovered and those with persistent morbidity. CONCLUSIONS: Post-earthquake morbidity persists longer in those who are older, have a history of emotional problems, have higher neuroticism, use more neurotic defenses, and report higher levels of post-disaster life events. 2010-04-27T06:04:33.696Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2787 Hypsometry has historically been used as an indicator of geomorphic form of catchments and landforms. Yet there has been little work aimed at relating hypsometry to landform process and scale. This paper uses the SIBERIA catchment evolution model to explore linkages between catchment process and hypsometry. SIBERIA generates results that are qualitatively and quantitatively similar to observed hypsometric curves for physically realistic parameters. However, we show that not only does the hypsometry reflect landscape runoff and erosion process, but it is strongly dependent on channel network and catchment geometry. We show that the width to length ratio of the catchment has a significant influence on the shape of the hypsometric curve, though little on the hypsometric integral. For landforms dominated by fluvial sediment transport, the classic Strahler mature hypsometric curve is only generated for catchments with roughly equal width and length. Narrow catchments show a hypsometric curve more similar to Strahler's monadnock form. For landscapes dominated by diffusive transport, the simulated hypsometric curve is concave-down everywhere, this being consistent with curves reported for some example catchments in France. Because the transition between diffusive dominance to fluvial is scale-dependent, with larger catchments exhibiting greater fluvial dominance, then the hypsometric curve is a scale-dependent descriptor of landforms. Experimental results for simulated landforms from a small-scale rainfall-erosion simulator are reported. It is shown that SIBERIA yields satisfactory fits to the data, confirming its ability to predict the form of the hypsometric curve from a simple model of geomorphic processes. 2010-04-27T06:04:22.016Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2785 Two studies are reported in which high school students were forced to process a text containing a geographical map. In Study 1, 86 students read the materials under one of four different conditions in which levels of processing of the text and accompanying map were varied: Question Mapcue (the materials contained adjunct questions and cues to inspect the provided map); Question Map (the materials contained adjunct questions but no cues to inspect the provided map); Question (the material contained adjunct questions and no map was provided); and Text (the materials contained no adjunct questions and no map was provided). A number of recognition and recall tests showed no significant differences among the conditions. A map task showed superior performance on recalling information related to the events in the text by Question Mapcue students of high reading ability. Study 2, with 94 students, employed a deeper directed or forced processing condition in which students were required to actually draw on the map itself, the Mapdraw condition (an extension of the Question Mapcue condition in Study 1). The two other conditions were Question Mapcue (as in Study 1) and, as control, Question Map (as for Study 1). Results from recognition and recall testing showed positive effects for drawing on the map, but only if accompanied by high reading ability. Implications for independent student learning are discussed. 2010-04-27T06:04:19.966Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2790 Circulating platelets are primed to respond very rapidly to thrombogenic stimuli, but most platelets complete their lifespan without ever becoming activated. Platelet activation is accompanied by waves of sequential tyrosine phosphorylation thought to involve members of the Src family of protein tyrosine kinases (PTKs). We show here that resting platelets contain highly active pp53/56(Lyn) PTK within membrane microdomains (rafts) isolated biochemically with or without the use of detergent. This fraction is also greatly enriched in the transmembrane glycoprotein CD36, known to associate with Lyn PTK, but in transfection studies we could find no evidence to suggest that CD36 affects the distribution or function of Lyn. Upon platelet activation Lyn activity remains constant or diminishes and pp60(c-src) PTK within this fraction becomes highly activated, indicating the dynamic nature of the membrane microdomains. It is suggested that the function of active Lyn PTK in the resting platelet is to allow prolonged survival of this anucleate cell. 2010-04-27T06:04:12.596Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:2788 Decay-accelerating factor (DAF), a widely expressed membrane complement-regulatory protein, is utilized as a cellular receptor by many human enteric pathogens. We show here that the binding of two enteroviruses to individual short consensus repeats (SCR) of DAF on the cell surface is greatly augmented by mAb binding to an alternate SCR: Coxsackievirus A21 binding to the SCR1 of DAF is increased by Ab binding to SCR3 and, conversely, Echovirus 7 binding to SCR3 is enhanced severalfold by Ab binding to SCR1. These Ab-induced increases in viral binding also resulted in increased viral infectivity. Using purified soluble DAF in a solid phase assay it was found that Ab binding to SCR1 is increased greatly in the presence of an Ab against SCR3 and, reciprocally, Ab against SCR1 greatly increases Ab binding to SCR3. In contrast to the results obtained with the larger viral particles, however, this reciprocal Ab-induced enhancement of binding is not seen when measuring Ab binding to membrane-bound DAF SCR on the cell surface. These findings provide a possible explanation for functional differences between membrane-bound and soluble DAF with implications for a potential role for DAF-binding molecules in regulating DAF function. This is the first demonstration of enhancement of viral infectivity mediated by Ab against the viral receptor. 2010-04-27T06:04:10.195Z ]]>