178 resultados para Early reactions
em University of Queensland eSpace - Australia
Resumo:
Experimental models of orthotopic liver transplantation (OLT) have shown that the very early events post-OLT are critical in distinguishing immunogenic and tolerogenic reactions. In rodents, increased leukocyte apoptosis and cytokine expression have been demonstrated in tolerogenic strain combinations. Information from human OLT recipients is less abundant. The aim of this study was to determine the amount of early leukocyte activation and apoptosis following human OLT, and to correlate this with subsequent rejection status. Peripheral blood mononuclear cells (PBMC) were isolated from 76 patients undergoing OLT - on the day prior, 5 hrs after reperfusion (day 0), and 18-24 hrs post-OLT (day 1). The mean level of apoptotic PBMCs on post OLT day 1 was higher than healthy recipients (0.9% +/- 0.2 vs. 0.2% +/- 0.1, p = 0.013). Apoptosis was greater in nonrejecting (NR) (1.1% +/- 0.3) compared with acutely-rejecting (R) (0.3% +/- 0.1, p = 0.021) patients. On day 1, PBMC from NR patients had increased expression of IFN-gamma (p = 0.006), IL-10 (p = 0.016), and CD40 ligand (p = 0.02) compared with R. Donor cell chimerism on day 1 did not differ between the groups indicating that this was unlikely to account for increased PBMC apoptosis in the NR group. Interestingly, the level of chimerism on day 0 was significantly higher in NR (3.8% +/- 0.6) compared with R (1.2% +/- 0.4, p = 0.004) patients and there was a close correlation between chimerism on day 0 and cytokine expression on day 1. These results imply that similar mechanisms are occurring in the human liver to promote graft acceptance as in the experimental models of liver transplantation and suggest that strategies that promote liver transplant acceptance in rodents might be applicable to humans.
Resumo:
We present high-spatial resolution secondary ion mass spectrometry (SIMS) measurements of Pb and S isotopes in sulphides from early Archaean samples at two localities in southwest Greenland. Secondary pyrite from a 3.71 Ga sample of magnetite-quartz banded iron formation in the Isua Greenstone Belt, which has previously yielded unradiogenic Pb consistent with its ancient origin, contains sulphur with a mass independently fractionated (MIF) isotope signature (Delta(33)S =+3.3 parts per thousand). This reflects the secondary mineralization of remobilized sedimentary S carrying a component modified by photochemical reactions in the early Archaean atmosphere. It further represents one of the most extreme positive excursions so far known from the early Archaean rock record. Sulphides from a quartz-pyroxene rock and an ultramafic boudin from the island of Akilia, in the Godth (a) over circle bsfjord, have heterogeneous and generally radiogenic Pb isotopic compositions that we interpret to represent partial re-equilibration of Pb between the sulphides and whole rocks during tectonothermal events at 3.6, 2.7 and 1.6 Ga. Both these samples have Delta(33)S=0 (within analytical error) and therefore show no evidence for MIF sulphur. These data are consistent with previous interpretations that the rock cannot be proven to have a sedimentary origin. Our study illustrates that SIMS S-isotope measurements in ancient rocks can be used to elucidate early atmospheric parameters because of the ability to obtain combined S and Pb-isotope data, but caution must be applied when using such data to infer protolith. When information from geological context, petrography and chronology (i.e. by Pb isotopes) is combined and fully evaluated, Delta(33)S signatures from sulphides and their geological significance can be interpreted with a higher degree of confidence. (c) 2005 Elsevier B.V All rights reserved.
Resumo:
One factor that research suggests impedes positive contact between outgroup members is the experience of anxiety that can occur when anticipating negative consequences of such interactions. Research examining attitudes and behaviour towards same-sex attracted individuals indicates that this intergroup anxiety is particularly evident when the anticipated interaction involves members of the same gender. The current studies investigate the effect of timing of disclosure of a person’s same-sex attractions in an effort to identify a means of reducing this anxiety. Study 1 uses a hypothetical scenario to gain insight into participants’ stated preferences for early or delayed knowledge of a person’s sexual orientation. Results reveal an association between experiencing close contact with gay individuals of the same gender in real life (but not opposite gender), and a preference for early disclosure. Results from an experimental study concur with these findings. After a face-to-face interaction task with a confederate of the same gender, participants sit further from the confederate for the late disclosure condition when compared with the early disclosure and no disclosure control. Future studies investigating the interaction between timing of disclosure of same-sex attractions and the intimacy of disclosure (casual vs. intimate), are discussed.
Resumo:
Age-related changes in the adult language addressed to children aged 2;0-4;0 years in polyadic conditions were investigated in Australian childcare centres. The language that 21 staff members addressed to these children was coded for multiple variables in the broad social categories of prosody, context, speech act and gesture. The linguistic components were coded within the categories of phonology, lexicon, morphology, syntax and referential deixis. Minimal age-related differences were found. Explanations for the similarity of the adult language input across the age groups within the early childhood educational environment, will be discussed
Resumo:
The Equilibrium Flux Method [1] is a kinetic theory based finite volume method for calculating the flow of a compressible ideal gas. It is shown here that, in effect, the method solves the Euler equations with added pseudo-dissipative terms and that it is a natural upwinding scheme. The method can be easily modified so that the flow of a chemically reacting gas mixture can be calculated. Results from the method for a one-dimensional non-equilibrium reacting flow are shown to agree well with a conventional continuum solution. Results are also presented for the calculation of a plane two-dimensional flow, at hypersonic speed, of a dissociating gas around a blunt-nosed body.
Resumo:
We present a model linking perceptions of job insecurity to emotional reactions and negative coping behaviors. Our model is based on the idea that emotional variables explain, in part, discrepant findings reported in previous research. In particular, we propose that emotional intelligence moderates employees' emotional reactions to job insecurity and their ability to cope with associated stress. In this respect, low emotional intelligence employees are more likely than high emotional intelligence employees to experience negative emotional reactions to job insecurity and to adopt negative coping strategies.
Resumo:
Multiple gas solid reactions involving one solid and N gaseous reactants are investigated in this study by using a matched asymptotic expansion technique. Two cases are particularly studied. In the first case all N chemical reaction rates are faster than the diffusion rate. While in the second case only M (M < N) chemical reaction rates are faster than the diffusion rate and the rates of the remaining (N-M) chemical reactions are comparable to that of diffusion. For these two cases the solid concentration profile behaves like a travelling wave. In the first case the wave front velocity is contributed linearly by all gaseous reactants (additive law) while in the second case this law does not hold.
Resumo:
This work deals with a solution method to handle multicomponents reversible reactions occurring inside a porous catalyst pellet. The complexity of this problem arises from the fact that the effective diffusivities and Biot number, which characterizes the external mass transfer, are different for each chemical species. In mathematical terms, this means that each chemical species has its own subspace and, therefore, when the technique of finite integral transform is applied to solve this multicomponent problem, each chemical species is associated with its own integral transform kernel. The analytical solutions obtained for this problem are compact and simple for any further manipulation. Application of this result to the catalytic reforming of C7 hydrocarbon system is shown in this paper.
Resumo:
This is a highly original study of possession by demons and their exorcism, which was rife in early modern times, focussing on the place where they were most prevalent, France. Catholics at the time believed that the devil was present everywhere, in the rise of the heretics, in the activities of witches, and even in the bodies of the pious young women. The rite of exorcism was intended to heal the possessed and show the power of the church - but it generated as many problems as it resolved. Possessed nuns endured frequently violent exorcisms, exorcists were suspected of conjuring devils, and possession itself came to be seen as a form of holiness, elevating several women to the status of living saints. Sarah Ferber offers a challenging study of one of the most intriguing phenomena of early modern Europe; looking also at the present day, it argues that early modern conflicts over the devil still carry an unexpected force and significance for western Christianity (from publisher).
Resumo:
Provides background on the development and nature of Antarctic tourism and associated environmental issues, as well as agreements and regulations affecting environmental management in Antarctica. Following an outline of the survey methodology and provision of information on the socioeconomic profiles of the respondents, results of a survey of Antarctic tourists on the Russian registered ship the ‘Akademik Ioffe’ are reported. The importance of Antarctic wildlife as an attraction for these Antarctic tourists is then given particular attention. The study considers amongst other things how important Antarctic wildlife was in convincing these tourists to undertake their trip to Antarctica, the importance to the tourists of seeing different species of wildlife and the relative importance of wildlife compared with other attractions of the tour to Antarctica. Views both prior to and following visits to Antarctica are given. The views of the tourists about selected environmental issues involving Antarctica were canvassed. These are reported and discussed. Amongst the subjects discussed is whether the sampled tourists favour an expansion in tourism to Antarctica and why. An overall assessment completes the study.
Resumo:
The project was commissioned to investigate and analyse the issue of effective support for distance education students in the early years of school to maximise literacy and numeracy outcomes. The scope of this project was limited to students living in rural and remote areas who are undertaking education at home and who are in their early years of schooling. For the purpose of this project, the early years are conceptualised as the first three years of formal compulsory schooling in each of the States and Territories. There were a number of key tasks for the project which included: 1. Examining of the role of home tutors/supervisors This included interviewing personnel from the State and Territory distance education providers as well as the principals, teachers, home tutors and children. 2. Describing literacy and numeracy teaching and learning, and the use of information and communication technologies (ICT) in distance education This aspect of the project involved a critical review and analysis of relevant literature and reports in the last five years, and a consideration of the new initiatives that had been implemented in the States and Territories in the last two years. 3. The development of resources Through examination of the role of home tutors/supervisors, and an examination of literacy and numeracy and the use of technology in distance education, three resources were developed: ● A guide for home tutors/supervisors and schools of distance education about effective intervention and assessment strategies to support students’ learning and to assist the home tutors/supervisors in implementing ICT to support the development of literacy and numeracy in the early years. ● A calendar of activities for literacy and numeracy that would act as a stimulus for integrated and authentic activity for young children. ● An embryonic website of resources for the stakeholders in rural and distance education that might act as a catalyst for future resource building and sharing. In this way the final key task of the project, which was to create a context for a strategic dissemination plan, was realised when a strategy to address effective dissemination of the findings of the project so as to maximise their usefulness for the relevant groups was achieved.
Resumo:
Previous studies have shown that multiple ; birth children (MBC) are prone to early phonological ;difficulties and later literacy problems. However, to date, ;there has been no systematic long-term follow-up of MBC with phonological difficulties in the preschool years to determine whether these difficulties predict later literacy problems. In this study, 20 MBC whose early speech and language skills had been previously documented were compared to normative data and 20 singleton controls on tasks assessing phonological ; processing and literacy. The major findings indicated that MBC performed significantly more poorly on some tasks :df phonological processing than singleton controls did. Further, the early phonological skills of MBC (i.e., the number of inappropriate phonological processes used) correlated with poor performance on visual rhyme recognition, word repetition, and phoneme detection tasks 5 years later. There was no significant relationship between early biological factors (birth weight and gestation period) and performance on the phonological processing and literacy-related subtests. These results cl-support the hypothesis that MBC's early speech and language difficulties are not merely a transient phase;of; development, but a real disorder, with consequences for later academic achievement.
Resumo:
Background & Aims: An elevated transferrin saturation is the earliest phenotypic abnormality in hereditary hemochromatosis. Determination of transferrin saturation remains the most useful noninvasive screening test for affected individuals, but there is debate as to the appropriate screening level. The aims of this study were to estimate the mean transferrin saturation in hemochromatosis heterozygotes and normal individuals and to evaluate potential transferrin saturation screening levels. Methods: Statistical mixture modeling was applied to data from a survey of asymptomatic Australians to estimate the mean transferrin saturation in hemochromatosis heterozygotes and normal individuals. To evaluate potential transferrin saturation screening levels, modeling results were compared with data from identified hemochromatosis heterozygotes and homozygotes. Results: After removal of hemochromatosis homozygotes, two populations of transferrin saturation were identified in asymptomatic Australians (P < 0.01). In men, 88.2% of the truncated sample had a lower mean transferrin saturation of 24.1%, whereas 11.8% had an increased mean transferrin saturation of 37.3%. Similar results were found in women, A transferrin saturation threshold of 45% identified 98% of homozygotes without misidentifying any normal individuals. Conclusions: The results confirm that hemochromatosis heterozygotes form a distinct transferrin saturation subpopulation and support the use of transferrin saturation as an inexpensive screening test for hemochromatosis. In practice, a fasting transferrin saturation of greater than or equal to 45% identifies virtually all affected homozygous subjects without necessitating further investigation of unaffected normal individuals.