27 resultados para One-meson-exchange model

em Deakin Research Online - Australia


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This paper serves to integrate social exchange with organisational justice and performance theory. Social exchange relationships are represented by employees’ perceptions of workplace inequity and evaluated using justice rules. Employees are expected to have in-role and extra-role behavioural responses and cognitive responses to inequity. It is theorised that behavioural and cognitive responses are moderated by the employee’s perceptions of organisational justice. Much employee performance, commitment, engagement, retention and turnover may be explained by this comprehensive model.

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A practical experiment is described which was used to help university students increase their understanding of the effect of construction methods and window design on passive solar heating and electrical heating. A number of one tenth scale model rooms were constructed by students and sited out-of-doors in the late autumn. The models were fabricated to mimic available commercial construction techniques with careful consideration being given to window size and placement for solar access. Each model had a thermostatically controlled electric heating element. The temperatures and electricity use of the models were recorded using data-loggers over a two week period. The performances of the models based on energy consumption and internal temperature were compared with each other and with predictions based upon thermal mass and R-values. Examples of questions used by students to facilitate this process are included. The effect of scaling on thermal properties was analysed using Buckingham’s p-theorem.

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A large volume of TCP/IP traffic is currently, and in the future will be, carried over ATM networks. A major part of the traffic, which is produced by multimedia sources, is encoded using the MPEG standard. For the performance analysis of transferring MPEG video sequence via TCP/IP over A TM networks, there is a need for appropriate simulation models. This paper describes one such simulation model that we have constructed. A sct of preliminary simulation experiments have been conducted with the mode to assess the impact of different network configurations on the MPEG traffic transmission performance. Our simulation model is able to simulate many of the potential performance issues regarding video traffic via TCPIIP and A TM and can be used to evaluate any potential solutions.

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Topotecan (TPT) is a semisynthetic water-soluble derivative of camptothecin (CPT) used as second-line therapy in patients with metastatic ovarian carcinoma, small cell lung cancer, and other malignancies. However, both doselimiting toxicity and tumor resistance hinder the clinical use of TPT. The mechanisms for resistance to TPT are not fully defined, but increased efflux of the drug by multiple drug transporters including P-glycoprotein (PgP), multidrug resistance associated protein 1 (MRP1) and breast cancer resistance protein (BCRP) from tumor cells has been highly implicated. This study aimed to investigate whether overexpression of human MRP4 rendered resistance to TPT by examining the cytotoxicity profiles using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazonium bromide (MTT) assay and cellular accumulation of TPT in HepG2 cells stably overexpressing MRP4. Two kinds of cell lines, HepG2 with insertion of an empty vector plasmid (V/HepG2), HepG2 cells stably expressing MRP4 (MRP4/HepG2), were exposed to TPT for 4 or 48 hr in the absence or presence of various MRP4 inhibitors including DL-buthionine-(S,R)-sulphoximine (BSO), diclofenac, celecoxib, or MK-571. The intracellular accumulation of TPT and paclitaxel (a PgP substrate) by V/HepG2 and MRP4/HepG2 cells was determined by incubation of TPT with the cells and the amounts of the drug in cells were determined by validated HPLC methods. The study demonstrated that MRP4 conferred a 12.03- and 6.86-fold resistance to TPT in the 4- and 48-hr drug-exposure MTT assay, respectively. BSO, MK-571, celecoxib, or diclofenac sensitised MRP4/HepG2 cells to TPT cytotoxicity and partially reversed MRP4-mediated resistance to TPT. In addition, the accumulation of TPT was significantly reduced in MRP4/HepG2 cells compared to V/HepG2 cells, and one-binding site model was found the best fit for the MRP4-mediated efflux of TPT, with an estimated Km of 1.66 mM and Vmax of 0.341 ng/min/106 cells. Preincubation of MRP4/HepG2 cells with BSO (200 μM) for 24 hr, celecoxib (50 mM), or MK-571 (100 mM) for 2 hr significantly increased the accumulation of TPT over 10 min in MRP4/HepG2 cells by 28.0%, 37.3% and 32.5% (P < 0.05), respectively. By contrast, there was no significant difference in intracellular accumulation of paclitaxel in V/HepG2 and MRP4/HepG2 cells over 120 min. MRP4 also rendered resistance to adefovir dipivoxil (bis-POMPMEA) and methotrexate, two reported MRP4 substrates. MRP4 did not exhibit any significant resistance to other model drugs including vinblastine, vincristine, etoposide, carboplatin, cyclosporine and paclitaxel in both long (48 hr) and short (4 hr) drug-exposure MTT assays. These findings indicate that MRP4 confers resistance to TPT and TPT is the substrate for MRP4. Further studies are needed to explore the role of MRP4 in resistance to, toxicity and pharmacokinetics of TPT in cancer patients.

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The clinical use of irinotecan (CPT-11) is hindered by dose-limiting diarrhea and myelosuppression. Recent clinical studies indicate that thalidomide, a known tumor necrosis factor-alpha inhibitor, ameliorated the toxicities induced by CPT-11. However, the mechanisms for this are unknown. This study aimed to investigate whether combination of thalidomide modulated the toxicities of CPT-11 using a rat model and the possible role of the altered pharmacokinetic component in the toxicity modulation using in vitro models. The toxicity model was constructed by treatment of healthy rats with CPT-11 at 60 mg/kg per day by intravenous (i.v.) injection. Body weight, acute and delayed-onset diarrhea, blood cell counts, and macroscopic and microscopic intestinal damages were monitored in rats treated with CPT-11 alone or combined therapy with thalidomide at 100 mg/kg administered by intraperitoneal (i.p.) injection. Single dose and 5-day multiple-dose studies were conducted in rats to examine the effects of concomitant thalidomide on the plasma pharmacokinetics of CPT-11 and its major metabolites SN-38 and SN-38 glucuronide (SN-38G). The effect of CPT-11 on thalidomide's pharmacokinetics was also checked. Rat liver microsomes and a rat hepatoma cell line, H4-II-E cells, were used to study the in vitro metabolic interactions between these two drugs. H4-II-E cells were also used to investigate the effect of thalidomide and its hydrolytic products on the transport of CPT-11 and SN-38. In addition, the effect of thalidomide and its hydrolytic products on rat plasma protein binding of CPT-11 and SN-38 was examined. Administration of CPT-11 by i.v. for 4 consecutive days to rats induced significant body weight loss, decrease in neutrophil and lymphocyte counts, severe acute- and delayed-onset diarrhea, and intestinal damages. These toxicities were alleviated when CPT-11 was combined with thalidomide. In both single-dose and 5-day multiple-dose pharmacokinetic study, coadministered thalidomide significantly increased the area under the plasma concentration-time curve (AUC) of CPT-11, but the AUC and elimination half-life (t(1/2)) of SN-38 were significantly decreased. However, CPT-11 did not significantly alter the pharmacokinetics of thalidomide. Thalidomide at 25 and 250 microM and its hydrolytic products at a total concentration of 10 microM had no significant effect on the plasma protein binding of CPT-11 and SN-38, except for that thalidomide at 250 microM caused a significant increase in the unbound fraction (f(u)) of CPT-11 by 6.7% (P < 0.05). The hydrolytic products of thalidomide (total concentration of 10 microM), but not thalidomide, significantly decreased CPT-11 hydrolysis by 16% in rat liver microsomes (P < 0.01). The formation of both SN-38 and SN-38G from CPT-11, SN-38 glucuronidation, or intracellular accumulation of both CPT-11 and SN-38 in H4-II-E cells followed Michaelis-Menten kinetics with the one-binding site model being the best fit for the kinetic data. Coincubation or 2-hr preincubation of thalidomide at 25 microM and 250 microM and its hydrolytic products at 10 microM did not show any significant effects on CPT-11 hydrolysis and SN-38 glucuronidation. However, preincubation of H4-II-E cells with thalidomide (250 microM), its hydrolytic products (total concentration of 10 microM), or phthaloyl glutamic acid (one major thalidomide hydrolytic product, 10 microM) significantly increased the intracellular accumulation of SN-38, but not CPT-11 (P < 0.01). The dose-limiting toxicities of CPT-11 were alleviated by combination with thalidomide in rats and the pharmacokinetic modulation by thalidomide may partially explain its antagonizing effects on the toxicities of CPT-11. The hydrolytic products of thalidomide, instead of the parental drug, modulated the hepatic hydrolysis of CPT-11 and intracellular accumulation of SN-38, probably contributing to the altered plasma pharmacokinetics of CPT-11 and SN-38. Further studies are needed to explore the role of both pharmacokinetics and pharmacodynamic components in the protective effect of thalidomide against the toxicities of CPT-11.

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The first aim of the research was to determine the applicability of certain variables from the Health Belief Model (HBM), the Theory of Reasoned Action (TRA), the risk dimensions from the Psychometric Paradigm, the Common-Sense Model of Illness Representations and the Locus of Control to Italian women’s beliefs and behaviours in relation to screening mammography. These models have predominantly been derived and evaluated with English-speaking persons. The study used quantitative and qualitative methods to enable explanation of research-driven and participant-driven issues. The second aim was to include Italian women in health behaviour research and to contrast the Italian sample with the Anglo-Australian sample to determine if differences exist in relation to their beliefs. In Australia many studies in health behaviour research do not include women whose first language is not English. The third aim was to evaluate the Anti-Cancer Council of Victoria’s (ACCV) Community Language Program (CLP) by: (a) identifying the strengths and weaknesses of the program as seen by the participants; and (b) assessing the impact of the program on women’s knowledge and beliefs about breast cancer, early detection of breast cancer, self-reported and intended breast screening behaviours. The CLP is an information service that uses women’s first language to convey information to women whose first language is not English. The CLP was designed to increase knowledge about breast and cervical cancer. The research used a pre-test-intervention-post-test design with 174 Italian-born and 138 Anglo-Australian women aged 40 years and over. Interviews for the Italian sample were conducted in Italian. The intervention was an information session that related to breast health and screening mammography. Demographic variables were collected in the Pre-Test only. Qualitative open-ended questions that related specifically to the information session were collected in the Post-Test phase of the study. Direct logistic regression was used with the participants’ beliefs and behaviours to identify the relevant variables for language (Italian speaking and English-speaking), attendance to an information session, mammography screening and breast self-examination (BSE) behaviour. Pre- and Post-Test comparisons were conducted using chi-square tests for the non-parametric data and paired sample t-tests for the parametric data. Differences were found between the Italian and Anglo-Australian women in relation to their beliefs about breast cancer screening. The Italian women were: (1) more likely to state that medical experts understood the causes of breast cancer; (2) more likely to feel that they had less control over their personal risk of getting breast cancer; (3) more likely to be upset and frightened by thinking about breast cancer; (4) less likely to perceive breast cancer as serious; (4) more likely to only do what their doctor told them to do; and (5) less likely to agree that there were times when a person has cancer and they don’t know it. A pattern emerged for the Italian and Anglo-Australian women from the logistic regression analyses. The Italian women were much more likely to comply with medical authority and advice. The Anglo-Australian women were more likely to feel that they had some control over their health. Specifically, the risk variable ‘dread’ was more applicable to the Italian women’s behaviour and internal locus of control variable was more relevant to the Anglo-Australian women. The qualitative responses also differed for the two samples. The Italian women’s comments were more general, less specific, and more limited than that of the Anglo-Australian women. The Italian women talked about learning how to do BSE whereas the Anglo-Australian women said that attending the session had reminded them to do BSE more regularly. The key findings and contributions of the present research were numerous. The focus on one cultural group ensured comprehensive analyses, as did the inclusion of an adequate sample size to enable the use of multivariate statistics. Separating the Italian and Anglo-Australian samples in the analyses provided theoretical implications that would have been overlooked if the two groups were combined. The use of both qualitative and quantitative data capitalised on the strengths of both techniques. The inclusion of an Anglo-Australian group highlighted key theoretical findings, differences between the two groups and unique contributions made by both samples during the collection of the qualitative data. The use of a pre-test-intervention-post-test design emphasised the reticence of the Italian sample to participate and talk about breast cancer and confirmed and validated the consistency of the responses across the two interviews for both samples. The inclusion of non-cued responses allowed the researcher to identify the key salient issues relevant to the two groups. The limitations of the present research were the lack of many women who were not screening and reliance on self-report responses, although few differences were observed between the Pre- and Post-Test comparisons. The theoretical contribution of the HBM and the TRA variables was minimal in relation to screening mammography or attendance at the CLP. The applicability of these health behaviour theories may be less relevant for women today as they clearly knew the benefits of and the seriousness of breast cancer screening. The present research identified the applicability of the risk variables to the Italian women and the relevance of the locus of control variables to the Anglo-Australian women. Thus, clear cultural differences occurred between the two groups. The inclusion of the illness representations was advantageous as the responses highlighted ideas and personal theories salient to the women not identified by the HBM. The use of the illness representations and the qualitative responses further confirmed the relevance of the risk variables to the Italian women and the locus of control variables to the Anglo-Australian women. Attendance at the CLP did not influence the women to attend for mammography screening. Behavioural changes did not occur between the Pre- and Post-Test interviews. Small incremental changes as defined by the TTM and the stages of change may have occurred. Key practical implications for the CLP were identified. Improving the recruitment methods to gain a higher proportion of women who do not screen is imperative for the CLP promoters. The majority of the Italian and Anglo-Australian women who attended the information sessions were women who screen. The fact that Italian women do not like talking or thinking about cancer presents a challenge to promoters of the CLP. The key theoretical finding that Italian women dread breast cancer but comply with their doctor provides clear strategies to improve attendance at mammography screening. In addition, the inclusion of lay health advisors may be one way of increasing attendance to the CLP by including Italian women already attending screening and likely to have attended a CLP session. The present research identified the key finding that improving Anglo-Australian attendance at an information session is related to debunking the myth surrounding familial risk of breast cancer and encouraging the Anglo-Australian women to take more control of their health. Improving attendance for Italian women is related to reducing the fear and dread of breast cancer and building on the compliance pattern with medical authority. Therefore, providing an information session in the target language is insufficient to attract non-screeners to the session and then to screen for breast cancer. Suggestions for future research in relation to screening mammography were to include variables from more than one theory or model, namely the risk, locus of control and illness representations. The inclusion of non-cued responses to identify salient beliefs is advantageous. In addition, it is imperative to describe the profile of the cultural sample in detail, include detailed descriptions of the translation process and be aware of the tendency of Italian women to acquiesce with medical authority.

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This article introduces the conceptual practice tool of ‘The Vortex of Violence’ and one suggested practice model for utilising the vortex of violence in practice with women who have experienced a domestic violence relationship. The practice tool and model are an expansion of ‘The Cycle of Violence’ that shifts the focus from explanation of the dynamics of abusive relationships to the exploration of the lived experience of women and the development of a personal/therapeutic template for healing and reclaiming of their lives.

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Blended learning models are widely-used, successful training vehicles for e-learning and workplace training, in corporate as well as higher education environments. Increasingly, Web 2.0 applications, imbedded within blended learning models, are being recognized for their utility in these settings. Concern for the sustainability and relevance of nonprofit organizations has sharpened the interest in building effective capacity-building models for the sector. Can Web 2.0 technologies enhance capacity-building models in the Third Sector? Because blended learning is a remarkably adaptable and fluid model, its potential for transforming capacity-building models in the nonprofit sector is thought to be significant. This paper introduces the concept of transformational approaches to capacity-building and asks if blended learning paradigms that incorporate interactive next-generation technologies might strike a responsive chord in the sector. The authors present research to date on blended learning and capacity-building to lay the foundation for the introduction of one blended learning model for training and education in the nonprofit sector. While the authors suggest that blended learning, as it is evolving, is the key to driving innovation in capacity-building models, they recognize that tailoring blended learning to the audience is critical in achieving success. It is suggested that for optimal results, capacity-building efforts should be built on holistic approaches to the integration of individual self-actualization goals with mechanisms for organizational and sector empowerment, using the technologies imbedded with blended learning. © 2011 Springer-Verlag.

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This study examines the mediating effects of cognitive trust and affective trust on the relationship between supervisors' participative leadership behavior and subordinate work outcomes, using data obtained from 247 dyads in a manufacturing organization located in mainland China. Structural equation modeling revealed that while affective trust fully mediated the relationships between participative leadership of supervisor and subordinate job performance and organizational citizenship behavior, cognitive trust had non-significant effects. These findings underscore the importance of interpersonal interactions between the supervisor and subordinate for engendering subordinate work outcomes. They also lend support to the exchange (relationship)-based explanation as to how trust enhances the response of subordinates to the participative leadership behavior of their immediate supervisor, given that affective trust involves a process of social exchange between both parties over an extended period of time. © 2014 © 2014 Taylor & Francis.

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The foreign exchange (FX) market has many features including (1) Each trader’s payoff depends not only on his own behavior, but also on other traders’ decisions; (2) The number of traders is too large to make them all know the other dealers’ methods of decision making; and (3) The FX market has many levels. The FX market is complex because of these features. A diversity of techniques are required to deal with such complex problems. That is hybrid solutions are crucial for the FX market. On the other hand, research into the FX market has revealed that it demonstrates some characteristics of multi-agent systems such as autonomy, interaction, and emergence. To this end, an agent-based hybrid intelligent system was developed for FX trading, which is based on our proposed agent-based hybrid framework. This paper is to discuss the analysis, design, and implementation such a system. Some experimental results and comparisons with related works are also provided. The interest of this paper does not reside in improving the predictive capabilities of different FX models, but rather in how to integrate different models into one system under the unifying agent framework. The success of this system indicates that agent perspectives are very appropriate to model complex problems such as the FX trading.

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This paper develops a model of exchange rate determination within an error correction framework. The intention is to identify both long and short term determinants that can be used to forecast the AUD/US exchange rate. The paper identifies a set of significant variables associated with exchange rate movements over a twenty year period from 1984 to 2004. Specifically, the overnight interest rate differential, Australia's foreign trade-weighted exposure to commodity prices as well as exchange rate volatility are variables identified that are able explain movements in the AUDIUS dollar relationship. An error correction model is subsequently constructed that incorporates an equilibrium correction term, a short-term interest rate differential variable, a commodity price variable and a proxy for exchange rate volatility. The model is then used to forecast out of sample and is found to dominate a naIve random walk model based on three different metrics.

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In this paper, we consider daily financial data from various sources (stock market indices, foreign exchange rates and bonds) and analyze their multiscaling properties by estimating the parameters of a Markov-switching multifractal (MSM) model with Lognormal volatility components. In order to see how well estimated models capture the temporal dependency of the empirical data, we estimate and compare (generalized) Hurst exponents for both empirical data and simulated MSM models. In general, the Lognormal MSM models generate "apparent" long memory in good agreement with empirical scaling provided that one uses sufficiently many volatility components. In comparison with a Binomial MSM specification [11], results are almost identical. This suggests that a parsimonious discrete specification is flexible enough and the gain from adopting the continuous Lognormal distribution is very limited.

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Ownership concentration as a governance mechanism has received considerable attention among academician, practitioners as well as policy makers because large-block shareholders are increasingly active in their demands that corporations adopt effective governance mechanisms to control managerial decisions, which include corporate debt policy. Earlier study on the agency model of the firm widely recognizes that the managerial ownership and external debt play an important role in mitigating agency conflicts and enhancing firm value. They also found that increase in the external monitors, for example the institutional investors, can actually play a useful role in limiting agency problems in the firm. This paper, using 100 Composite Index companies from Brusa Malaysia between 1998 to 2002 explores the impact of institutional holdings on managerial ownership and debt policy in an integrated framework by using a simultaneous equations estimation procedure (2SLS). The findings show that there is a significant impact of institutional ownership which serves effective control mechanism on managerial ownership and corporate debt policy as hypothesized. Findings of such evidence suggest that institutional holding thus have played an important role in managers' strategic management decision and reduce agency conflict. In addition, corporate debt policy too is governed by managerial ownership and exhibited a negative relation.