A hybrid simulated annealing and perturb and observe method for maximum power point tracking in PV systems under partial shading conditions

This paper presents a hybrid method for Maximum Power Point Tracking (MPPT) of a Photovoltaic (PV) system which experiences non-uniform environmental conditions or partial shading conditions. The hybrid method combines two simple techniques with complementary strengths in achieving Global MPPT. Simulated Annealing (SA) has only recently been applied to PV MPPT and is very effective at locating global maxima with limited implementation complexity. Perturb and Observe (P&O) is a very common technique which provides continuous tracking of the MPP in a simple and easy to implement manner. The P&O method is generally incapable of locating global maxima, and the SA based method is unable to perform continuous searching. By merging these techniques in a hybrid MPPT method consisting of a global searching stage and a local searching stage, the tracking performance is improved compared to what each technique could achieve independently. Simulation results are presented to demonstrate the effectiveness of the proposed hybrid technique.

Maximum power point tracking techniques for photovoltaic systems: a comprehensive review and comparative analysis

Maximum Power Point Tracking (MPPT) is an important concern in Photovoltaic (PV) systems. As PV systems have a high cost of energy it is essential that they are operated to extract the maximum possible power at all times. However, under non-uniform environmental conditions, which frequently arise in the outdoor environment, many MPPT techniques will fail to track the global peak power. This review paper discusses conventional MPPT techniques designed to operate under uniform environmental conditions and highlights why these techniques fail under non-uniform conditions. Following this, techniques designed specifically to operate under non-uniform environmental conditions are analysed and compared. Simulation results which compare the performance of the common Perturb and Observe (P&O) method, the Particle Swarm Optimisation (PSO) and the Simulated Annealing (SA) MPPT approaches under non-uniform environmental conditions are also presented. The research presented in this review indicates that there is no single technique which can achieve reliable global MPPT with low cost and complexity and be easily adapted to different PV systems.

A simulated annealing global maximum power point tracking approach for PV modules under partial shading conditions

This paper proposes a simulated annealing (SA)-based global maximum power point tracking (GMPPT) technique designed for photovoltaic (PV) systems which experience partial shading conditions (PSC). The proposed technique is compared with the common perturb and observe MPPT technique and the particle swarm optimization method for GMPPT. The performance is assessed by considering the time taken to converge and the number of sample cases where the technique converges to the GMPP. Simulation results indicate the improved performance of the SA-based GMPPT algorithm, with arbitrarily selected parameters, in tracking to the global maxima in a multiple module PV system which experiences PSC. Experimental validation of the technique is presented based on PV modules that experience nonuniform environmental conditions. Additionally, studies regarding the influence of the key parameters of the SA-based algorithm are described. Simulation and experimental results verify the effectiveness of the proposed GMPPT method.

Characterization of a distinct plasma membrane macrodomain in differentiated adipocytes.

Caveolae are small invaginations of the cell surface that are abundant in mature adipocytes. A recent study (Kanzaki, M., and Pessin, J. E. (2002) J. Biol. Chem. 277, 25867-25869) described novel caveolin- and actin-containing structures associated with the adipocyte cell surface that contain specific signaling proteins. We have characterized these structures, here termed "caves," using light and electron microscopy and observe that they represent surface-connected wide invaginations of the basal plasma membrane that are sometimes many micrometers in diameter. Rather than simply a caveolar domain, these structures contain all elements of the plasma membrane including clathrin-coated pits, lipid raft markers, and non-raft markers. GLUT4 is recruited to caves in response to insulin stimulation. Caves can occupy a significant proportion of the plasma membrane area and are surrounded by cortical actin. Caveolae density in caves is similar to that on the bulk plasma membrane, but because these structures protrude much deeper into the plane of focus of the light microscope molecules such as caveolin and other plasma membrane proteins appear more concentrated in caves. We conclude that the adipocyte surface membrane contains numerous wide invaginations that do not represent novel caveolar structures but rather large surface caves.

Studies in supervisory practice : the effectiveness of the practicum in teacher education in the Northern Territory

In this thesis we descend into the swampy lowlands to meet with student-teachers and their supervisors and observe them working together at different sites across the Top End of Australia. In the process we discover the multiple relationships that comprise the practicum text and the discomforting untidiness and unwieldiness, as well as the awkwardness of complexity, which surrounds research into supervisory practice. The thesis demonstrates the need to attend to the subjectivities of the participants and highlights the conflicting attitudes, beliefs, interests, and desires which are only partially realised or understood. It moves us beyond language to the sentient world of anger, love, disgust, hope, fear, despair, joy, anguish, and pain and we become immersed in a murky, incoherent, interior world of hints, shadows, and unfamiliar sounds, a world of lost innocence and conflict in which knowledge is truly embodied. Encompassing a view of supervision as moral praxis, particular attention was given to the care and protection of the self and a romanticist conception of the self was seen to predominate. The thesis demonstrates the part played by positioning and agency in the process of subjectification, the importance of emotional and relational bonding in the emergence of collegiality, the tactics of power employed by supervisors, the struggle for personal autonomy, the presence of anxiety induced by failure to pro vide feedback, the inculcation of guilt, and the complex interplay of age-related and gender effects. Attention is also given to the degree to which supervisors adopt reflective and constructivist approaches to their work. The stories reveal that supervision is much more than advising student-teachers on curriculum content, resource availability and lesson presentation. It is a process of interiority in which supervisors may need to provide emotional support in the face of displacement and disorientation, and assume the role of an abiding presence, someone capable of imaginative introjection, someone who ‘knows’. Particular attention is paid to the language of supervision which was marked by indirection, diffidence, imprecision, irony, and understatement. At the same time, the agonistic nature of language associated with the politics of the personal is made apparent. Whilst in the opinion of Liaison Lecturers, context-of-site did not appear to matter as far as acquiring teaching competence was concerned, the failure to attend to context-of-site affected how student-teachers engaged with difference and diversity. In spite of attempts to contest the myths of Aboriginal education and interrupt the discourse of impoverishment, colonialist attitudes and resistance to liberatory education persisted. The thesis ends with suggestions for alternatives to the traditional practicum and discusses the introduction of Field-Based Teacher Education into Northern Territory schools.

Effect of selenium-saturated bovine lactoferrin (Se-bLF) on antioxidant enzyme activities in human gut epithelial cells under oxidative stress

Cancer and many chronic inflammatory diseases are associated with increased amounts of reactive oxygen species (ROS). The potential cellular and tissue damage created by ROS has significant impact on many disease and cancer states and natural therapeutics are becoming essential in regulating altered redox states. We have shown recently that iron content is a critical determinant in the antitumour activity of bovine milk lactoferrin (bLF). We found that 100% iron-saturated bLF (Fe-bLF) acts as a potent natural adjuvant and fortifying agent for augmenting cancer chemotherapy and thus has a broad utility in the treatment of cancer. Furthermore, we also studied the effects of iron saturated bLF's ability as an antioxidant in the human epithelial colon cancer cell line HT29, giving insights into the potential of bLF in its different states. Thus, metal saturated bLF could be implemented as anti-cancer neutraceutical. In this regard, we have recently been able to prepare a selenium (Se) saturated form of bLF, being up to 98% saturated. Therefore, the objectives of this study were to determine how oxidative stress induced by hydrogen peroxide (H₂O₂) alters antioxidant enzyme activity within HT29 epithelial colon cancer cells, and observe changes in this activity by treatments with different antioxidants ascorbic acid (AA), Apo (iron free)-bLF and selenium (Se)-bLF. The states of all antioxidant enzymes (glutathione peroxidase (GPx), glutathione reductase (GR), glutathione-s-transferase (GsT), catalase and superoxide dismutase (SOD)) demonstrated high levels within untreated HT29 cells compared to the majority of other treatments being used, even prior to H₂O₂ exposure. All enzymes showed significant alterations in activity when cells were treated with antioxidants AA, Apo-bLF or Se-bLF, with and/or without H₂O₂ exposure. Obvious indications that the Se content of the bLF potentially interacted with the glutathione (GSH)/GPx/GR/GsT associated redox system could be observed immediately, showing capability of Se-bLF being highly beneficial in helping to maintain a balance between the oxidant/antioxidant systems within cells and tissues, especially in selenium deficient systems. In conclusion, the antioxidative defence activity of Se-bLf, investigated in this study for the first time, shows dynamic adaptations that may allow for essential protection from the imbalanced oxidative conditions. Because of its lack of toxicity and the availability of both selenium and bLF in whole milk, Se-bLF offers a promise for a prospective natural dietary supplement, in addition to being an immune system enhancement, or a potential chemopreventive agent for cancers.

Crime toolkits : the current threats to web applications

Increasingly, web applications are being developed over the Internet. Securing these web applications is becoming important as they hold critical security features. However, cybercriminals are becoming smarter by developing a crime toolkit, and employing sophisticated techniques to evade detection. These crime toolkits can be used by any person to target Internet users. In this paper, we explore the techniques used in crime toolkits. We present a current state-of-the-art analysis of crime toolkits and focus on attacks against web applications. The crime toolkit techniques are compared with the vulnerability of web applications to help reveal particular behaviour such as popular web application vulnerabilities that malicious writers prefer. In addition, we outline the existing protection mechanism, and observe that the possibility for damage is rising, particularly as specialization and scale increase in cybercrime.

If waterbirds are nocturnal are we conserving the right habitats?

Waterbirds are key indicators of wetland health and recent declines in their abundance have renewed focus on conservation of their habitats in Australia. Yet conservation efforts have mostly ignored the identification of habitats used at night. In this study we assessed three common species, Grey Teal (Anas gracilis), Chestnut Teal (Anas castanea) and Australian Wood Duck (Chenonetta chubata), during day and night. Thermal imaging technologies were utilised to identify individuals to species, count abundances and observe habitat requirements. We found major differences in abundance between night and day of all three species at our study sites. Further, habitat use of teals differed between nocturnal and diurnal hours, with birds aggregating on the bank during daylight hours and moving onto the water during the night. Our findings suggest that nocturnal waterbird surveys can assist conservation efforts. By monitoring bird numbers by night, the significance of a habitat for feeding and shelter purposes can be determined. Additionally, by studying nocturnal behaviour and habitat use, identification and conservation of important wetlands will be increased.

Ensuring quality during monitoring of the learning environment of government primary schools achieved through EUI-PDP for teachers and head teachers

A positive change in the learning environment in schools is visible through ongoing professional development of teachers and administrators. Monitoring the professional development program and providing support to teachers and administrators to transfer their learnings into the school environment ensures some measures of quality. Quality issues led to the launching of the Professional Development Program (PDP) for Primary School Teachers (PSTs) of Sindh by the United Educational Initiative (UEI), a consortium of five Governmental and Non-Governmental Organizations, working under the supervision of Education Sector Reform Assistance (ESRA). Implementation of the UEI-PDP in four districts of Sindh, is ensured by a team of professionals in each district. Recognising that capacity building of district education employees would improve the educational system in the country, 130 Master Trainers were selected, on merit, from the District Education Office for the training of 17,000 teachers and 3000 Head teachers/administrators over a period of two years. This paper developed the design of a Monitoring Process for a Professional Development Program for Primary School Teachers and Administrators. Data was collected through Pre/Post observations, Interviews, Questionnaires and Reports. Such tools make it possible for the monitoring teams to observe, to inquire further, and, along with the Managers, Master Trainers and School Support Team, seek to explain the progress of the program and take corrective action where indicated. Both formative evaluations as well as summative  evaluation techniques are utilized for evaluating the program. The monitoring process that assisted in formative evaluations is described. In order to assist in summative evaluation, data collected through the monitoring process was further developed to categorize the schools where teachers and head teachers are trained. It is hoped that the categorization of the schools may lead to further improvements in those schools which fall in the group for need improvement. It may also initiate further research as to reasons behind why some schools are in the good category and why others fall in the average category.

Auditor independence: regulation, oversight and inspection

Much of what auditors do is unobservable. Indeed, what goes on in an audit has been described as ‘secret audit business’. Audits in this context are of financial reports and those financial reports are the representations of the management of those companies, not the auditors. The audits of financial reports are of value in that they provide a competent and independent (of auditee management) attestation of the validity of those management representations. This attestation lowers the ‘information risk’ for the users of these financial reports. There has been a marked increase in activity to regulate matters relating to independence. The proposals outlined in CLERP 9 are one example of this. The requirements in the United States under the Sarbanes-Oxley Act are a further example.

Audit firms operate in a highly regulated yet highly competitive market. Evidence exists to suggest that audit firms are active competitors in respect of audit pricing and competency, including specialist industry expertise. Until recently, there has been little or no observable evidence that audit firms compete in respect of independence. The issues as they relate to audit independence are complex. One issue is that threats to independence are frequently subtle and difficult to observe and measure. Hence, controlling the decisions that relate to them cannot rely solely on regulation which itself inevitably relies on crude definitions and imprecise measures. Additionally, further regulation may not achieve the desired end without other processes being but in place in tandem.

This paper argues that:

1. auditors of certain classes of companies (in particular, those that are publicly traded) should be provided with incentives or requirements to have observable processes on independence
2. the means of observability should be in the form of an inspection and review process focussing on issues critical to the audit, such as independence
3. expert persons not having a current or past financial interest in the firm or in the commercial outcomes of the review should be used in the inspection and review process
4. the review process should have wide-ranging powers of inspection to examine the policies, processes, structures and ‘culture’ of audit firms
5. the report of the inspection and review should be made public, unedited and in full, and in a timely fashion. The primary objectives of this proposal are to (1) make more transparent to the market for information the characteristics of the audit firms and their process to ensure audit independence, and (2) provide a rigorous oversight of independence decision-making by persons who have no commercial interest in the outcome of the decision.

The effect of exercise and training status on platelet activation: do cocoa polyphenols play a role?

Sedentary and trained men respond differently to the same intensity of exercise, this is probably related to their platelet reactivity and antioxidant capacity. There is growing interest in the utilization of antioxidant-rich plant extracts as dietary food supplements. The aim of this study was to investigate the effect of an acute bout of sub maximal exercise on platelet count and differential response of platelet activation in trained and sedentary subjects and to observe if cocoa polyphenols reverse the effect of exercise on platelet function. The practical significance of this study was that many sedentary people engage in occasional strenuous exercise that may predispose them to risk of heart disease. Fasting blood samples were collected from 16 male subjects, pre and post 1-h cycling exercise at 70% of maximal aerobic power (VO2max) before and after consumption of cocoa or placebo. Agonist stimulated citrated whole blood was utilized for measuring platelet aggregation, adenosine triphosphate (ATP) release and platelet activation. Baseline platelet count (221 ± 33 times 109/L) and ATP release (1.4 ± 0.6 nmol) increased significantly (P < 0.05) after exercise in all subjects. Baseline platelet numbers in the trained were higher (P < 0.05) than in the sedentary (235 ± 37 vs. 208 ± 34 times 109/L), where as platelet activation in trained was lower (P < 0.05) than sedentary (51 ± 6 vs. 59 ± 5%). Seven days of cocoa polyphenol supplementation had little effect on any of the parameters measured. We conclude that trained subjects show decreased activation of stimulated platelets when compared to the sedentary subjects and short-term cocoa polyphenol supplementation did not decrease platelet activity in response to exercise independent of prior training status.

Measuring offender discount rates : an overview of the issues and a suggested methodology

Criminologists assert that some offenders exhibit impulsive behaviour. If this is correct then this impulsiveness will manifest itself through high discount rates. However discount rates are difficult to observe and measure. In this paper a methodology is proposed, which considerably reduces the complexity of this task, through observing the offender’s actual plea decision. This is a valuable exercise because the results can be usefully utilised in formulating policy as well as providing insights into offender psychology.

Interacting amino acid preferences of 3D pattern pairs at the binding sites of transient and obligate protein complexes

To assess the physico-chemical characteristics of protein-protein interactions, protein sequences and overall structural folds have been analyzed previously. To highlight this, discovery and examination of amino acid patterns at the binding sites defined by structural proximity in 3-dimensional (3D) space are essential. In this paper, we investigate the interacting preferences of 3D pattern pairs discovered separately in transient and obligate protein complexes. These 3D pattern pairs are not necessarily sequence-consecutive, but each residue in two groups of amino acids from two proteins in a complex is within certain °A threshold to most residues in the other group. We develop an algorithm called AA-pairs by which every pair of interacting proteins is represented as a bipartite graph, and it discovers all maximal quasi-bicliques from every bipartite graph to form our 3D pattern pairs. From 112 and 2533 highly conserved 3D pattern pairs discovered in the transient and obligate complexes respectively, we observe that Ala and Leu is the highest occuring amino acid in interacting 3D patterns of transient (20.91%) and obligate (33.82%) complexes respectively. From the study on the dipeptide composition on each side of interacting 3D pattern pairs, dipeptides Ala-Ala and Ala-Leu are popular in 3D patterns of both transient and obligate complexes. The interactions between amino acids with large hydrophobicity difference are present more in the transient than in the obligate complexes. On contrary, in obligate complexes, interactions between hydrophobic residues account for the top 5 most occuring amino acid pairings.

Design and simulation of an interdigital-chaotic advection micromixer for lab-on-a-chip applications

This paper presents the design and simulation of a novel passive micromixer. The micromixer consists of two inlet tanks, one mixing channel and two outlet channels. In order to maximise the mixing efficiency, the following considerations are made: (i) The inlet tanks are followed by a series of microchannels, in which the flow is split. The microchannels are arranged in an interdigital manner to maximise the contact area between the two flows. (ii) The microchannels attached to the lower inlet tank have an upward slope while those attached to the upper tank have a downward slope. The higher-density flow is fed to the lower inlet tank and gets an upward velocity before entering the mixing channel. (iii) Two triangular barriers are placed within the mixing channel to impose chaotic advection and perturb the less-mixed flow along the top and bottom surfaces of the channel. (iv) Finally, two outlet channels are incorporated to discard the less-mixed flow. Three-dimensional simulations are carried out to evaluate the performance of the micromixer. Simulations are performed in the absence and presence of the gravitational force to analyse the influence of gravity on the micromixer. Mixing efficiencies of greater than 92% are achieved using water and a 1011'density biological solvent as the mixing fluids.

Expectancy violation and perceptions of rape victim credibility

Purpose. Rape victims have been found to have a heightened risk of secondary victimization in the legal system through biased perceptions of their credibility. In this study, participants observed a video of a rape victim reporting the crime and evaluated her credibility, to establish the influence of victim emotional expressiveness on evaluations of victim credibility. Methods. The nonverbal (eye-contact, crying) and paralinguistic (tone of voice) behaviour of the rape victim was manipulated such that the emotional presentation viewed by observers was either expressive, or not expressive. One hundred and thirty seven participants were randomly allocated to observe a videotape of either an expressive or a non-expressive victim. Participants' specific expectations about the emotional expressiveness of rape victims in general were also measured. Results. Results revealed no significant main effect of emotional expressiveness on perceptions of credibility. However, among participants with a strong expectation of emotional expressiveness, a rape victim who was emotionally expressive was perceived to be significantly more credible than a victim who was not emotionally expressive. Conclusions. It appears to be expectancy violation rather than emotional expressiveness per se that biases observers' perceptions of rape victim credibility.