250 resultados para Transfer RNA (tRNA)
Resumo:
Purpose — The purpose of this chapter is to outline the findings of research into knowledge transfer across countries and culture and the implications of the findings for human resource practitioners. Methodology/approach — Use of a qualitative case study methodology approach was employed. Findings — The findings highlight the inherent difficulty of knowledge transfer and the broad range of factors that influence the knowledge transfer process and which are connected together in a complex and non-linear manner. Research implications — The research revealed insight into those managers most likely to be effective at knowledge transfer and what characteristics and experiences had supported this openness to knowledge from outside of their cultural context. The lessons from the research can be incorporated into the selection and development processes for expatriates. Originality value — The study affirmed the critical importance of face-to-face interaction in knowledge transfer. The research also resulted in the development of a practical model and tool, which pulls together the broad range of factors that impact on knowledge transfer.
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This paper argues that a possible cause of issues with management education outcomes is the fact that most training models operate from a limited ‘transfer’ metaphor. This theoretical paper contends that by reconceptualising existing models, specifically Holton’s transfer of learning model, to incorporate multiple processes and acknowledge the importance of educator- or trainer-student interaction in co-creating knowledge, there is potential to improve training design and ultimately achieve more satisfactory training outcomes.
Resumo:
Purpose: Experimental measurements have been made to investigate meaning of the change in voltage for the pulse gas metal arc welding (GMAW-P) process operating under different drop transfer modes. Design/methodology/approach: Welding experiments with different values of pulsing parameter and simultaneous recording of high speed camera pictures and welding signals (such as current and voltage) were used to identify different drop transfer modes in GMAW-P. The investigation is based on the synchronization of welding signals and high speed camera to study the behaviour of voltage signal under different drop transfer modes. Findings: The results reveal that the welding arc is significantly affected by the molten droplet detachment. In fact, results indicate that sudden increase and drop in voltage just before and after the drop detachment can be used to characterize the voltage behaviour of different drop transfer mode in GMAW-P. Research limitations/implications: The results show that voltage signal carry rich information about different drop transfer occurring in GMAW-P. Hence it’s possible to detect different drop transfer modes. Future work should concentrate on development of filters for detection of different drop transfer modes. Originality/value: Determination of drop transfer mode with GMAW-P is crucial for the appropriate selection of pulse welding parameters. As change in drop transfer mode results in poor weld quality in GMAW-P, so in order to estimate the working parameters and ensure stable GMAW-P understanding the voltage behaviour of different drop transfer modes in GMAW-P will be useful. However, in case of GMAW-P hardly any attempt is made to analyse the behaviour of voltage signal for different drop transfer modes. This paper analyses the voltage signal behaviour of different drop transfer modes for GMAW-P.
Resumo:
The underlying objective of this study was to develop a novel approach to evaluate the potential for commercialisation of a new technology. More specifically, this study examined the 'ex-ante'. evaluation of the technology transfer process. For this purpose, a technology originating from the high technology sector was used. The technology relates to the application of software for the detection of weak signals from space, which is an established method of signal processing in the field of radio astronomy. This technology has the potential to be used in commercial and industrial areas other than astronomy, such as detecting water leakages in pipes. Its applicability to detecting water leakage was chosen owing to several problems with detection in the industry as well as the impact it can have on saving water in the environment. This study, therefore, will demonstrate the importance of interdisciplinary technology transfer. The study employed both technical and business evaluation methods including laboratory experiments and the Delphi technique to address the research questions. There are several findings from this study. Firstly, scientific experiments were conducted and these resulted in a proof of concept stage of the chosen technology. Secondly, validation as well as refinement of criteria from literature that can be used for „ex-ante. evaluation of technology transfer has been undertaken. Additionally, after testing the chosen technology.s overall transfer potential using the modified set of criteria, it was found that the technology is still in its early stages and will require further development for it to be commercialised. Furthermore, a final evaluation framework was developed encompassing all the criteria found to be important. This framework can help in assessing the overall readiness of the technology for transfer as well as in recommending a viable mechanism for commercialisation. On the whole, the commercial potential of the chosen technology was tested through expert opinion, thereby focusing on the impact of a new technology and the feasibility of alternate applications and potential future applications.
Resumo:
This article examines the current transfer pricing regime to consider whether it is a sound model to be applied to modern multinational entities. The arm's length price methodology is examined to enable a discussion of the arguments in favour of such a regime. The article then refutes these arguments concluding that, contrary to the very reason multinational entities exist, applying arm's length rules involves a legal fiction of imagining transactions between unrelated parties. Multinational entities exist to operate in a way that independent entities would not, which the arm's length rules fail to take into account. As such, there is clearly an air of artificiality in applying the arm's length standard. To demonstrate this artificiality with respect to modern multinational entities, multinational banks are used as an example. The article concluded that the separate entity paradigm adopted by the traditional transfer pricing regime is incongruous with the economic theory of modern multinational enterprises.
Resumo:
In response to developments in international trade and an increased focus on international transfer-pricing issues, Canada’s minister of finance announced in the 1997 budget that the Department of Finance would undertake a review of the transfer-pricing provisions in the Income Tax Act. On September 11, 1997, the Department of Finance released draft transfer-pricing legislation and Revenue Canada released revised draft Information Circular 87-2R. The legislation was subsequently amended and included in Bill C-28, which received first reading on December 10, 1997. The new rules are intended to update Canada’s international transfer-pricing practices. In particular, they attempt to harmonize the standards in the Income Tax Act with the arm’s-length principle established in the OECD’s transfer pricing guidelines. The new rules also set out contemporaneous documentation requirements in respect of cross-border related-party transactions, facilitate administration of the law by Revenue Canada, and provide for a penalty where transfer prices do not comply with the arm’s-length principle. The Australian tax authorities have similarly reviewed and updated their transfer-pricing practices. Since 1992, the Australian commissioner of taxation has issued three rulings and seven draft rulings directly relating to international transfer pricing. These rulings outline the selection and application of transfer pricing methodologies, documentation requirements, and penalties for non-compliance. The Australian Taxation Office supports the use of advance pricing agreements (APAs) and has expanded its audit strategy by conducting transfer-pricing risk assessment reviews. This article presents a detailed review of Australia’s transfer-pricing policy and practices, which address essentially the same concerns as those at which the new Canadian rules are directed. This review provides a framework for comparison of the approaches adopted in the two jurisdictions. The author concludes that although these approaches differ in some respects, ultimately they produce a similar result. Both regimes set a clear standard to be met by multinational enterprises in establishing transfer prices. Both provide for audits and penalties in the event of noncompliance. And both offer the alternative of an APA as a means of avoiding transfer-pricing disputes with Australian and Canadian tax authorities.
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The human Ureaplasma species are the most frequently isolated bacteria from the upper genital tract of pregnant women and can cause clinically asymptomatic, intra-uterine infections, which are difficult to treat with antimicrobials. Ureaplasma infection of the upper genital tract during pregnancy has been associated with numerous adverse outcomes including preterm birth, chorioamnionitis and neonatal respiratory diseases. The mechanisms by which ureaplasmas are able to chronically colonise the amniotic fluid and avoid eradication by (i) the host immune response and (ii) maternally-administered antimicrobials, remain virtually unexplored. To address this gap within the literature, this study investigated potential mechanisms by which ureaplasmas are able to cause chronic, intra-amniotic infections in an established ovine model. In this PhD program of research the effectiveness of standard, maternal erythromycin for the treatment of chronic, intra-amniotic ureaplasma infections was evaluated. At 55 days of gestation pregnant ewes received an intra-amniotic injection of either: a clinical Ureaplasma parvum serovar 3 isolate that was sensitive to macrolide antibiotics (n = 16); or 10B medium (n = 16). At 100 days of gestation, ewes were then randomised to receive either maternal erythromycin treatment (30 mg/kg/day for four days) or no treatment. Ureaplasmas were isolated from amniotic fluid, chorioamnion, umbilical cord and fetal lung specimens, which were collected at the time of preterm delivery of the fetus (125 days of gestation). Surprisingly, the numbers of ureaplasmas colonising the amniotic fluid and fetal tissues were not different between experimentally-infected animals that received erythromycin treatment or infected animals that did not receive treatment (p > 0.05), nor were there any differences in fetal inflammation and histological chorioamnionitis between these groups (p > 0.05). These data demonstrate the inability of maternal erythromycin to eradicate intra-uterine ureaplasma infections. Erythromycin was detected in the amniotic fluid of animals that received antimicrobial treatment (but not in those that did not receive treatment) by liquid chromatography-mass spectrometry; however, the concentrations were below therapeutic levels (<10 – 76 ng/mL). These findings indicate that the ineffectiveness of standard, maternal erythromycin treatment of intra-amniotic ureaplasma infections may be due to the poor placental transfer of this drug. Subsequently, the phenotypic and genotypic characteristics of ureaplasmas isolated from the amniotic fluid and chorioamnion of pregnant sheep after chronic, intra-amniotic infection and low-level exposure to erythromycin were investigated. At 55 days of gestation twelve pregnant ewes received an intra-amniotic injection of a clinical U. parvum serovar 3 isolate, which was sensitive to macrolide antibiotics. At 100 days of gestation, ewes received standard maternal erythromycin treatment (30 mg/kg/day for four days, n = 6) or saline (n = 6). Preterm fetuses were surgically delivered at 125 days of gestation and ureaplasmas were cultured from the amniotic fluid and the chorioamnion. The minimum inhibitory concentrations (MICs) of erythromycin, azithromycin and roxithromycin were determined for cultured ureaplasma isolates, and antimicrobial susceptibilities were different between ureaplasmas isolated from the amniotic fluid (MIC range = 0.08 – 1.0 mg/L) and chorioamnion (MIC range = 0.06 – 5.33 mg/L). However, the increased resistance to macrolide antibiotics observed in chorioamnion ureaplasma isolates occurred independently of exposure to erythromycin in vivo. Remarkably, domain V of the 23S ribosomal RNA gene (which is the target site of macrolide antimicrobials) of chorioamnion ureaplasmas demonstrated significant variability (125 polymorphisms out of 422 sequenced nucleotides, 29.6%) when compared to the amniotic fluid ureaplasma isolates and the inoculum strain. This sequence variability did not occur as a consequence of exposure to erythromycin, as the nucleotide substitutions were identical between chorioamnion ureaplasmas isolated from different animals, including those that did not receive erythromycin treatment. We propose that these mosaic-like 23S ribosomal RNA gene sequences may represent gene fragments transferred via horizontal gene transfer. The significant differences observed in (i) susceptibility to macrolide antimicrobials and (ii) 23S ribosomal RNA sequences of ureaplasmas isolated from the amniotic fluid and chorioamnion suggests that the anatomical site from which they were isolated may exert selective pressures that alter the socio-microbiological structure of the bacterial population, by selecting for genetic changes and altered antimicrobial susceptibility profiles. The final experiment for this PhD examined antigenic size variation of the multiple banded antigen (MBA, a surface-exposed lipoprotein and predicted ureaplasmal virulence factor) in chronic, intra-amniotic ureaplasma infections. Previously defined ‘virulent-derived’ and ‘avirulent-derived’ clonal U. parvum serovar 6 isolates (each expressing a single MBA protein) were injected into the amniotic fluid of pregnant ewes (n = 20) at 55 days of gestation, and amniotic fluid was collected by amniocentesis every two weeks until the time of near-term delivery of the fetus (at 140 days of gestation). Both the avirulent and virulent clonal ureaplasma strains generated MBA size variants (ranging in size from 32 – 170 kDa) within the amniotic fluid of pregnant ewes. The mean number of MBA size variants produced within the amniotic fluid was not different between the virulent (mean = 4.2 MBA variants) and avirulent (mean = 4.6 MBA variants) ureaplasma strains (p = 0.87). Intra-amniotic infection with the virulent strain was significantly associated with the presence of meconium-stained amniotic fluid (p = 0.01), which is an indicator of fetal distress in utero. However, the severity of histological chorioamnionitis was not different between the avirulent and virulent groups. We demonstrated that ureaplasmas were able to persist within the amniotic fluid of pregnant sheep for 85 days, despite the host mounting an innate and adaptive immune response. Pro-inflammatory cytokines (interleukin (IL)-1â, IL-6 and IL-8) were elevated within the chorioamnion tissue of pregnant sheep from both the avirulent and virulent treatment groups, and this was significantly associated with the production of anti-ureaplasma IgG antibodies within maternal sera (p < 0.05). These findings suggested that the inability of the host immune response to eradicate ureaplasmas from the amniotic cavity may be due to continual size variation of MBA surface-exposed epitopes. Taken together, these data confirm that ureaplasmas are able to cause long-term in utero infections in a sheep model, despite standard antimicrobial treatment and the development of a host immune response. The overall findings of this PhD project suggest that ureaplasmas are able to cause chronic, intra-amniotic infections due to (i) the limited placental transfer of erythromycin, which prevents the accumulation of therapeutic concentrations within the amniotic fluid; (ii) the ability of ureaplasmas to undergo rapid selection and genetic variation in vivo, resulting in ureaplasma isolates with variable MICs to macrolide antimicrobials colonising the amniotic fluid and chorioamnion; and (iii) antigenic size variation of the MBA, which may prevent eradication of ureaplasmas by the host immune response and account for differences in neonatal outcomes. The outcomes of this program of study have improved our understanding of the biology and pathogenesis of this highly adapted microorganism.
Resumo:
As two neighbouring countries, the number of transnational programs between Indonesian and Australian universities is significant. However, little is known about how transnational programs can facilitate knowledge transfer between the partner universities, which is often assumed by the Indonesian universities. Based on a case study regarding a dual degree program between an Indonesian and an Australian university, this paper outlines preliminary findings concerning the role of social ties between the staff of the two partner universities in creating positive inter-university dynamics that is vital for successful knowledge transfer. Using an inter-organisational knowledge transfer theoretical framework, social ties between the staff of the two universities are viewed as an important agent in facilitating knowledge transfer by building trust between the partners, moderating the perception about risk in the partnership, and creating a more equal power relation between the universities. Based on this study, Australian lecturers of Indonesian background and Indonesian lecturers who are alumni of Australian universities are important to initially establish these social ties. While face-to-face contact is still perceived as the ideal means of transferring knowledge and building trust among the Indonesian university staff, those who have stronger social ties with their Australian counterparts tend to use ICT-based communication to acquire knowledge from the Australian university compared to those who have more limited social ties with their Australian counterparts. This paper concludes with some implications for building positive social ties between Indonesian and Australian university staff to strengthen the knowledge transfer process.
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Evidence for a two-metal ion mechanism for cleavage of the HH16 hammerhead ribozyme is provided by monitoring the rate of cleavage of the RNA substrate as a function of La3+ concentration in the presence of a constant concentration of Mg2+. We show that a bell-shaped curve of cleavage activation is obtained as La3+ is added in micromolar concentrations in the presence of 8 mM Mg2+, with a maximal rate of cleavage being attained in the presence of 3 microM La3+. These results show that two-metal ion binding sites on the ribozyme regulate the rate of the cleavage reaction and, on the basis of earlier estimates of the Kd values for Mg2+ of 3.5 mM and > 50 mM, that these sites bind La3+ with estimated Kd values of 0.9 and > 37.5 microM, respectively. Furthermore, given the very different effects of these metal ions at the two binding sites, with displacement of Mg2+ by La3+ at the stronger (relative to Mg2+) binding site activating catalysis and displacement of Mg2+ by La3+ at the weaker (relative to Mg2+) (relative to Mg2+) binding site inhibiting catalysis, we show that the metal ions at these two sites play very different roles. We argue that the metal ion at binding site 1 coordinates the attacking 2'-oxygen species in the reaction and lowers the pKa of the attached proton, thereby increasing the concentration of the attacking alkoxide nucleophile in an equilibrium process. In contrast, the role of the metal ion at binding site 2 is to catalyze the reaction by absorbing the negative charge that accumulates at the leaving 5'-oxygen in the transition state. We suggest structural reasons why the Mg(2+)-La3+ ion combination is particularly suited to demonstrating these different roles of the two-metal ions in the ribozyme cleavage reaction.
Resumo:
Significant cleavage by hammerhead ribozymes requires activation by divalent metal ions. Several models have been proposed to account for the influence of metal ions on hammerhead activity. A number of recent papers have presented data that have been interpreted as supporting a one-metal-hydroxide-ion mechanism. In addition, a solvent deuterium isotope effect has been taken as evidence against a proton transfer in the rate-limiting step of the cleavage reaction. We propose that these data are more easily explained by a two-metal-ion mechanism that does not involve a metal hydroxide, but does involve a proton transfer in the rate-limiting step.