37 resultados para Vital


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We are interested in determining whether low maternal vitamin D-3 affects brain development in utero. Whilst the vitamin D receptor (VDR) has been identified in embryonic rat brains, the timing and magnitude of its expression across the brain remains unclear. In this study we have quantitated VDR expression during development as well correlated the timing of its appearance with two vital developmental events, apoptosis and mitosis. Brains from embryonic rats (embryonic days 15-23) were examined. We show that the well-described increase in apoptotic cells and decrease in mitotic cells during development correlates with the appearance of the VDR in brain tissue. Given that vitamin D-3 regulates mitosis and apoptosis in non-neuronal tissue we speculate that the timing of VDR expression in embryonic brain may directly or indirectly mediate features of neuronal apoptosis and mitosis.

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The recently discovered cyclotides kalata B1 and kalata B2 are miniproteins containing a head-to-tail cyclized backbone and a cystine knot motif, in which disulfide bonds and the connecting backbone segments form a ring that is penetrated by the third disulfide bond. This arrangement renders the cyclotides extremely stable against thermal and enzymatic decay, making them a possible template onto which functionalities can be grafted.We have compared the hydrodynamic properties of two prototypic cyclotides, kalata B1 and kalata B2, using analytical ultracentrifugation techniques. Direct evidence for oligomerization of kalata B2 was shown by sedimentation velocity experiments in which a method for determining size distribution of polydisperse molecules in solution was employed. The shape of the oligomers appears to be spherical. Both sedimentation velocity and equilibrium experiments indicate that in phosphate buffer kalata B1 exists mainly as a monomer, even at millimolar concentrations. In contrast, at 1.6 mM, kalata B2 exists as an equilibrium mixture of monomer (30%), tetramer (42%), octamer (25%), and possibly a small proportion of higher oligomers. The results from the sedimentation equilibrium experiments show that this self-association is concentration dependent and reversible. We link our findings to the three-dimensional structures of both cyclotides, and propose two putative interaction interfaces on opposite sides of the kalata B2 molecule, one involving a hydrophobic interaction with the Phe(6), and the second involving a charge-charge interaction with the Asp(25) residue. An understanding of the factors affecting solution aggregation is of vital importance for future pharmaceutical application of these molecules.

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The environmental fate of polycyclic aromatic hydrocarbons (PAHs) in soils is motivated by their wide distribution, high persistence, and potentially deleterious effect on human health. Polycyclic aromatic hydrocarbons constitute the largest group of environmental contaminants released in the environment. Therefore, the potential biodegradation of these compounds is of vital importance. A biocarrier suitable for the colonization by micro-organisms for the purpose of purifying soil contaminated by polycyclic aromatic hydrocarbons was developed. The optimized composition of the biocarrier was polyvinyl alcohol (PVA) 10%, sodium alginate (SA) 0.5%, and powdered activated carbon (PAC) 5%. There was no observable cytotoxicity of biocarriers on immobilized cells and a viable cell population of 1.86 x 10(10) g(-1) was maintained for immobilized bacterium. Biocarriers made from chemical methods had a higher biodegradation but lower mechanical strengths. Immobilized bacterium Zoogloea sp. had an ideal capability of biodegradation for phenanthrene and pyrene over a relative wide concentration range. The study results showed that the biodegradation of phenanthrene and pyrene reached 87.0 and 75.4%, respectively, by using the optimal immobilized method of Zoogloea sp. cultivated in a sterilized soil. Immobilized Zoogloea sp. was found to be effective for biodegrading the soil contaminated with phenanthrene and pyrene. Even in natural (unsterilized) soil, the biodegradation of phenanthrene and pyrene using immobilized Zoogloea sp. reached 85.0 and 67.1%, respectively, after 168 h of cultivation, more than twice that achieved if the cells were not immobilized on the biocarrier. Therefore, the immobilization technology enhanced the competitive ability of introduced micro-organisms and represents an effective method for the biotreatment of soil contaminated with phenanthrene and pyrene.

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Innate immunity plays a vital role in the protection of the bovine mammary gland against mastitis. Until recently, the migration of effector cells such as neutrophils and monocytes into the mammary gland was thought to provide the only defence against invading pathogens. However, mammary epithelial cells may also play an important role in the immune response, contributing to the innate defence of the mammary tissue through secretion of antimicrobial peptides and attraction of circulating immune effector cells. This paper reviews the innate immune pathways in mammary epithelial cells and examines their role in the initiation of an innate immune response to Gram-positive and Gram-negative bacteria.

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Making best use of resources is vital in developing countries that are struggling to improve public health with limited funds. The WHO-CHOICE project has developed standardised methods to,evaluate the efficiency of a broad range of interventions. Ibis series starts by assessing die problems with strategies for meeting the millennium development goals. Subsequent articles describe the methods, apply them to maternal and neonatal health, child health, HIV and AIDS, tuberculosis, and malaria, and consider the implications for an overall health strategy. All appear on bmj.com this week.

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In the course of daily living, humans frequently encounter situations in which a motor activity, once initiated, becomes unnecessary or inappropriate. Under such circumstances, the ability to inhibit motor responses can be of vital importance. Although the nature of response inhibition has been studied in psychology for several decades, its neural basis remains unclear. Using transcranial magnetic stimulation, we found that temporary deactivation of the pars opercularis in the right inferior frontal gyrus selectively impairs the ability to stop an initiated action. Critically, deactivation of the same region did not affect the ability to execute responses, nor did it influence physiological arousal. These findings confirm and extend recent reports that the inferior frontal gyrus is vital for mediating response inhibition.

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Background: A follow-up study was undertaken of all Western Australian women who had a new diagnosis of boast cancer during 1989. The aims were to determine survival, frequency of recurrence and quality of life (QoL) of Western Australian women 5 years after a diagnosis of breast cancer; to determine reasons for choice ol rejection of reconstructive surgery in those women treated by mastectomy, and to determine if the choice of lumpectomy or mastectomy affects subsequent QoL. Methods: The vital status as at Ist June 1994 of all 692 women who had a new diagnosis of breast cancer in 1989 was ascertained by electronic linkage to official mortality registrations. A subsample of 215 survivors who had originally been treated by the nine surgeons who had managed 20 or more cases each was sent a reply-paid postal questionnaire asking about follow-up treatment since diagnosis, recurrence of disease, current QoL and attitudes to, and use of, reconstructive surgery. Results: The overall survival rate at 5 years was 80.8% (85.9% and 78.8% for Stage I and II, respectively). Cumulative mortality was 35% lower among the third of patients treated by the nine most active surgeons (14% vs 22%, P < 0.02), but this may be subject to referral bias. The subsample was representative of all surviving cases except for being an average of 2.7 years younger at diagnosis (mean ages 55.2 and 57.9 years). The response rate of the subsample to the postal questionnaire was 78%. Of women who had had a mastectomy. 40% had considered having a reconstruction, but only nine (78%) had undergone this operation. Median QoL on the Rosser scale (maximum = 1.0) was 0.9. QoL was worse for the 23% of patients with a recurrence of breast cancer. Patients treated by breast-conserving surgery showed a trend toward a better QoL compared with those treated by mastectomy. Conclusion: At 5 years after the diagnosis of breast cancer, one in five women had died and an estimated one in four of the survivors had recurrent disease. Quality of life in the remaining patients, half of whom had undergone adjuvant treatment, was very good. These are important baseline data against which to judge the impact of mammographic screening.

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In a changing employment climate and with the growth of demand for careers guidance at all stages of life, careers guidance practice has moved from its positivist world view, with the counsellor as expert and client as passive responder, to more holistic 'constructivist' approaches. In essence, these approaches view the career as a holistic concept in which work and personal life are inextricably intertwined, and individuals are experts in their own lives, actively constructing their careers. The first to fully explore the constructivist approach, this book: provides a theoretical background to constructivism; outlines a range of constructivist approaches to career counselling; and gives examples of the practical application of constructivism. Essential for anyone involved in career guidance wishing to learn more about this vital new approach, this book combines theory with practicable guidance, and represents a new direction for career counselling.

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A recent study by Brook ef al. empirically tested the performance of population viability analysis (PVA) using data from 21 populations across a wide range of species. The study concluded that PVAs are good at predicting the future dynamics of populations. We suggest that this conclusion is a result of a bias in the studies that Brook et al, included in their analyses, We present arguments that PVAs can only be accurate at predicting extinction probabilities if data are extensive and reliable, and if the distribution of vital rates between individuals and years can be assumed stationary in the future, or if any changes can be accurately predicted. In particular, we note th at although catastrophes are likely to have precipitated many extinctions, estimates of the probability of catastrophes are unreliable.

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The presentation of an aesthetic identity involves the accomplishment of a coherent, plausible narrative which links one's choices to desired characteristics of the self. As symbolic evidence of a person's taste, material culture is a vital component of a successful narrative. Via case studies of pivotal household objects, this paper uses face-to-face interview data as a way of investigating processes of aesthetic choice. Household objects are interpreted as material elements imbricated in the presentation of a socially plausible and internally consistent aesthetic self. Narrative analysis, and the concept of the epiphany-object, are proposed as useful ways of accounting for tastes in domestic material culture. Methodological questions of truth-telling and authenticity in the face-to-face context are considered, and the sociological problem of taste is scrutinized in light of ideas about social accountability and textual identity.

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In its first term, the Howard government hired Australasian Research Strategies (ARS), headed by pollster Mark Textor, to conduct market research for several Commonwealth departments and agencies. This was, the Labor Opposition claimed, a case of the Liberals handing jobs to their 'mates'. Textor played a key role in the Liberals' 1996 and 1998 federal election campaigns. However, Labor's attack rings hollow since in the 1980s the Hawke government similarly contracted Rod Cameron's ANOP to conduct opinion research for Commonwealth departments and agencies. At the time Cameron was Labor's strategic pollster and centrally involved in planning Labor election campaigns. On both sides of Australian politics, governments have begun to channel patronage towards their party's pollsters. In this research note, we suggest that this development cannot be explained as 'jobs for the boys'. Instead, this new form of patronage has its roots in the vital role that pollsters now play in guiding election campaigns, and in the commercial reality that Australian politics provides too little work to sustain specialist political pollsters. Parties in government now appear to utilise incumbency to sustain an ongoing relationship with the commercial polling organisations like ANOP and ARS to whom they will entrust much of the planning of their campaign for re-election.

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Networking North Queensland (NNQ) was a two-year project to improve access to health services in rural and remote communities. The project involved email and Internet access in 61 communities, in a region almost three times the size of the UK. Videoconferencing equipment was also installed at 21 sites and a total of 197 h of videoconferencing was recorded at 10 of the remote sites over 12 months. As a result of the project, health consumers enjoyed improved access to medical, specialist, allied health and primary health services. In addition, health service providers had better access to reliable, up-to-date health-care information via intranet and Internet services. Consideration of local issues-local needs and existing resources-was vital to the achievements of the project. Community involvement and community access were also important factors in its success.

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Agricultural ecosystems and their associated business and government systems are diverse and varied. They range from farms, to input supply businesses, to marketing and government policy systems, among others. These systems are dynamic and responsive to fluctuations in climate. Skill in climate prediction offers considerable opportunities to managers via its potential to realise system improvements (i.e. increased food production and profit and/or reduced risks). Realising these opportunities, however, is not straightforward as the forecasting skill is imperfect and approaches to applying the existing skill to management issues have not been developed and tested extensively. While there has been much written about impacts of climate variability, there has been relatively little done in relation to applying knowledge of climate predictions to modify actions ahead of likely impacts. However, a considerable body of effort in various parts of the world is now being focused on this issue of applying climate predictions to improve agricultural systems. In this paper, we outline the basis for climate prediction, with emphasis on the El Nino-Southern Oscillation phenomenon, and catalogue experiences at field, national and global scales in applying climate predictions to agriculture. These diverse experiences are synthesised to derive general lessons about approaches to applying climate prediction in agriculture. The case studies have been selected to represent a diversity of agricultural systems and scales of operation. They also represent the on-going activities of some of the key research and development groups in this field around the world. The case studies include applications at field/farm scale to dryland cropping systems in Australia, Zimbabwe, and Argentina. This spectrum covers resource-rich and resource-poor farming with motivations ranging from profit to food security. At national and global scale we consider possible applications of climate prediction in commodity forecasting (wheat in Australia) and examine implications on global wheat trade and price associated with global consequences of climate prediction. In cataloguing these experiences we note some general lessons. Foremost is the value of an interdisciplinary systems approach in connecting disciplinary Knowledge in a manner most suited to decision-makers. This approach often includes scenario analysis based oil simulation with credible models as a key aspect of the learning process. Interaction among researchers, analysts and decision-makers is vital in the development of effective applications all of the players learn. Issues associated with balance between information demand and supply as well as appreciation of awareness limitations of decision-makers, analysts, and scientists are highlighted. It is argued that understanding and communicating decision risks is one of the keys to successful applications of climate prediction. We consider that advances of the future will be made by better connecting agricultural scientists and practitioners with the science of climate prediction. Professions involved in decision making must take a proactive role in the development of climate forecasts if the design and use of climate predictions are to reach their full potential. (C) 2001 Elsevier Science Ltd. All rights reserved.

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Forecasting category or industry sales is a vital component of a company's planning and control activities. Sales for most mature durable product categories are dominated by replacement purchases. Previous sales models which explicitly incorporate a component of sales due to replacement assume there is an age distribution for replacements of existing units which remains constant over time. However, there is evidence that changes in factors such as product reliability/durability, price, repair costs, scrapping values, styling and economic conditions will result in changes in the mean replacement age of units. This paper develops a model for such time-varying replacement behaviour and empirically tests it in the Australian automotive industry. Both longitudinal census data and the empirical analysis of the replacement sales model confirm that there has been a substantial increase in the average aggregate replacement age for motor vehicles over the past 20 years. Further, much of this variation could be explained by real price increases and a linear temporal trend. Consequently, the time-varying model significantly outperformed previous models both in terms of fitting and forecasting the sales data. Copyright (C) 2001 John Wiley & Sons, Ltd.

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This article aims to explore the relations between technology and the subject. With new media intensifying the provisionality of discursive structures and in turn embodied experiences, questions pertaining to virtuality have become vital, particularly since Western society's increasing reliance on technologies now permeates our everyday practices. While many theorists often resort to a reification of the subject when conceptualising the posthuman condition, this analysis will recover the notion of embodiment in order to avoid such technological determinism. Tracing this complexity in contemporary texts can be achieved through various means. Here, the focus will remain on how narrative frameworks can create new possibilities for understanding and interpreting shifting subjectivities in the digital age. To explore this, I shall provide an analysis of a contemporary film, Being John Malkovich, which has been chosen due to its unexpected success at the box office, indicating how finely attuned the film is to contemporary concerns.