971 resultados para Messía, Alonso (S.I.), 1665-1732
Resumo:
Numerous studies have reported links between insulin-like growth factors (IGFs) and the extra-cellular matrix protein vitronectin (VN). We ourselves have reported that IGF-I binds to VN via IGF-binding proteins (IGFBPs) to stimulate HaCaT and MCF-7 cell migration. Here, we detail the functional evaluation of IGFBP-1, -2, -3, -4 and -6 in the presence and absence of IGF-I and VN. The data presented here, combined with our prior data on IGFBP-5, suggest that IGFBP-3, -4 and -5 are the most effective at stimulating cell migration in combination with IGF-I and VN. In addition, we demonstrate that different regions within IGFBP-3 and -4 are critical for complex formation. Furthermore, we examine whether multi-protein complexes of IGF-I and IGFBPs associated with fibronectin and collagen IV are also able to enhance functional biological responses.
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Driver aggression is an increasing concern for motorists, with some research suggesting that drivers who behave aggressively perceive their actions as justified by the poor driving of others. Thus attributions may play an important role in understanding driver aggression. A convenience sample of 193 drivers (aged 17-36) randomly assigned to two separate roles (‘perpetrators’ and ‘victims’) responded to eight scenarios of driver aggression. Drivers also completed the Aggression Questionnaire and Driving Anger Scale. Consistent with the actor-observer bias, ‘victims’ (or recipients) in this study were significantly more likely than ‘perpetrators’ (or instigators) to endorse inadequacies in the instigator’s driving skills as the cause of driver aggression. Instigators were significantly more likely attribute the depicted behaviours to external but temporary causes (lapses in judgement or errors) rather than stable causes. This suggests that instigators recognised drivers as responsible for driving aggressively but downplayed this somewhat in comparison to ‘victims’/recipients. Recipients and instigators agreed that the behaviours were examples of aggressive driving but instigators appeared to focus on the degree of intentionality of the driver in making their assessments while recipients appeared to focus on the safety implications. Contrary to expectations, instigators gave mean ratings of the emotional impact of driving aggression on recipients that were higher in all cases than the mean ratings given by the recipients. Drivers appear to perceive aggressive behaviours as modifiable, with the implication that interventions could appeal to drivers’ sense of self-efficacy to suggest strategies for overcoming plausible and modifiable attributions (e.g. lapses in judgement; errors) underpinning behaviours perceived as aggressive.
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Recent studies have demonstrated that IGF-I associates with VN through IGF-binding proteins (IGFBP) which in turn modulate IGF-stimulated biological functions such as cell proliferation, attachment and migration. Since IGFs play important roles in transformation and progression of breast tumours, we aimed to describe the effects of IGF-I:IGFBP:VN complexes on breast cell function and to dissect mechanisms underlying these responses. In this study we demonstrate that substrate-bound IGF-I:IGFBP:VN complexes are potent stimulators of MCF-7 breast cell survival, which is mediated by a transient activation of ERK/MAPK and sustained activation of PI3-K/AKT pathways. Furthermore, use of pharmacological inhibitors of the MAPK and PI3-K pathways confirms that both pathways are involved in IGF-I:IGFBP:VN complex-mediated increased cell survival. Microarray analysis of cells stimulated to migrate in response to IGF-I:IGFBP:VN complexes identified differential expression of genes with previously reported roles in migration, invasion and survival (Ephrin-B2, Sharp-2, Tissue-factor, Stratifin, PAI-1, IRS-1). These changes were not detected when the IGF-I analogue (\[L24]\[A31]-IGF-I), which fails to bind to the IGF-I receptor, was substituted; confirming the IGF-I-dependent differential expression of genes associated with enhanced cell migration. Taken together, these studies have established that IGF-I:IGFBP:VN complexes enhance breast cell migration and survival, processes central to facilitating metastasis. This study highlights the interdependence of ECM and growth factor interactions in biological functions critical for metastasis and identifies potential novel therapeutic targets directed at preventing breast cancer progression.
Resumo:
Since the late 1990s, there has been great enthusiasm expressed about the positive impact that can be obtained for poor and disadvantaged people from information and communication technologies (ICTs). This school of thought among researchers and practitioners is identified as ICTs for development (ICT4D). By contrast, a growing number of researchers eschew the technologically deterministic nature of the claims being made for development progress and seek to understand the role of technology in people’s lives, primarily through ethnographic studies. This book, which focuses on mobile telephony on the African continent, fits into the latter body of literature, with several authors explicitly stating they are examining social and cultural settings and are not taking a technologically deterministic view. The book captures the diverse ways various communities are using this communication technology. It adds to the burgeoning field of mobile phone studies, in which an increasing number of studies is emerging from developing countries.
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Growth and profitability are often essential parts of the overall managerial goals of firms. High growth can be seen as an indicator of success and as a mean for achieving competitive advantage and higher profitability. But high growth can also lead to a number of managerial and organisational challenges, that may affect the profitability negatively. The aim of this article is to analyse the relationship between growth and profitability for Danish gazelle firms, and furthermore to investigate how the strategic orientation of the firm affects this relationship. Our study finds a clear positive relationship between growth and profitability among gazelle firms pursuing a broad market strategy. A managerial implication of this is that the growth strategy should be clearly integrated with the general strategic orientation of the firm.
Resumo:
The tear film plays an important role preserving the health of the ocular surface and maintaining the optimal refractive power of the cornea. Moreover dry eye syndrome is one of the most commonly reported eye health problems. This syndrome is caused by abnormalities in the properties of the tear film. Current clinical tools to assess the tear film properties have shown certain limitations. The traditional invasive methods for the assessment of tear film quality, which are used by most clinicians, have been criticized for the lack of reliability and/or repeatability. A range of non-invasive methods of tear assessment have been investigated, but also present limitations. Hence no “gold standard” test is currently available to assess the tear film integrity. Therefore, improving techniques for the assessment of the tear film quality is of clinical significance and the main motivation for the work described in this thesis. In this study the tear film surface quality (TFSQ) changes were investigated by means of high-speed videokeratoscopy (HSV). In this technique, a set of concentric rings formed in an illuminated cone or a bowl is projected on the anterior cornea and their reflection from the ocular surface imaged on a charge-coupled device (CCD). The reflection of the light is produced in the outer most layer of the cornea, the tear film. Hence, when the tear film is smooth the reflected image presents a well structure pattern. In contrast, when the tear film surface presents irregularities, the pattern also becomes irregular due to the light scatter and deviation of the reflected light. The videokeratoscope provides an estimate of the corneal topography associated with each Placido disk image. Topographical estimates, which have been used in the past to quantify tear film changes, may not always be suitable for the evaluation of all the dynamic phases of the tear film. However the Placido disk image itself, which contains the reflected pattern, may be more appropriate to assess the tear film dynamics. A set of novel routines have been purposely developed to quantify the changes of the reflected pattern and to extract a time series estimate of the TFSQ from the video recording. The routine extracts from each frame of the video recording a maximized area of analysis. In this area a metric of the TFSQ is calculated. Initially two metrics based on the Gabor filter and Gaussian gradient-based techniques, were used to quantify the consistency of the pattern’s local orientation as a metric of TFSQ. These metrics have helped to demonstrate the applicability of HSV to assess the tear film, and the influence of contact lens wear on TFSQ. The results suggest that the dynamic-area analysis method of HSV was able to distinguish and quantify the subtle, but systematic degradation of tear film surface quality in the inter-blink interval in contact lens wear. It was also able to clearly show a difference between bare eye and contact lens wearing conditions. Thus, the HSV method appears to be a useful technique for quantitatively investigating the effects of contact lens wear on the TFSQ. Subsequently a larger clinical study was conducted to perform a comparison between HSV and two other non-invasive techniques, lateral shearing interferometry (LSI) and dynamic wavefront sensing (DWS). Of these non-invasive techniques, the HSV appeared to be the most precise method for measuring TFSQ, by virtue of its lower coefficient of variation. While the LSI appears to be the most sensitive method for analyzing the tear build-up time (TBUT). The capability of each of the non-invasive methods to discriminate dry eye from normal subjects was also investigated. The receiver operating characteristic (ROC) curves were calculated to assess the ability of each method to predict dry eye syndrome. The LSI technique gave the best results under both natural blinking conditions and in suppressed blinking conditions, which was closely followed by HSV. The DWS did not perform as well as LSI or HSV. The main limitation of the HSV technique, which was identified during the former clinical study, was the lack of the sensitivity to quantify the build-up/formation phase of the tear film cycle. For that reason an extra metric based on image transformation and block processing was proposed. In this metric, the area of analysis was transformed from Cartesian to Polar coordinates, converting the concentric circles pattern into a quasi-straight lines image in which a block statistics value was extracted. This metric has shown better sensitivity under low pattern disturbance as well as has improved the performance of the ROC curves. Additionally a theoretical study, based on ray-tracing techniques and topographical models of the tear film, was proposed to fully comprehend the HSV measurement and the instrument’s potential limitations. Of special interested was the assessment of the instrument’s sensitivity under subtle topographic changes. The theoretical simulations have helped to provide some understanding on the tear film dynamics, for instance the model extracted for the build-up phase has helped to provide some insight into the dynamics during this initial phase. Finally some aspects of the mathematical modeling of TFSQ time series have been reported in this thesis. Over the years, different functions have been used to model the time series as well as to extract the key clinical parameters (i.e., timing). Unfortunately those techniques to model the tear film time series do not simultaneously consider the underlying physiological mechanism and the parameter extraction methods. A set of guidelines are proposed to meet both criteria. Special attention was given to a commonly used fit, the polynomial function, and considerations to select the appropriate model order to ensure the true derivative of the signal is accurately represented. The work described in this thesis has shown the potential of using high-speed videokeratoscopy to assess tear film surface quality. A set of novel image and signal processing techniques have been proposed to quantify different aspects of the tear film assessment, analysis and modeling. The dynamic-area HSV has shown good performance in a broad range of conditions (i.e., contact lens, normal and dry eye subjects). As a result, this technique could be a useful clinical tool to assess tear film surface quality in the future.
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This paper describes effective ways secondary school leaders can enact curriculum policy, particularly assessment practices, to support learning for students with disabilities in mainstream schools. Assessment for learning (AfL) as a pedagogic practice, has gained recent importance through inclusion in curriculum policy in Queensland, Australia. AfL is the frequent assessment of student progress that identifies learning needs and informs future teaching and learning. Assessment of student progress of the standards based curriculum has provided challenges for schools attempting to meet the needs of “all” learners. This paper highlights findings of a small case study to model successful leadership practices used in an inclusive secondary school to improve achievement of students with disabilities through assessment. Successful leadership practices that can be generalized to improve achievement of all learners include making sense of policy for staff; developing staff common and shared beliefs and actions; organizing professional learning opportunities and arranging collaborative curriculum planning and co-teaching.
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CRE (Corporate Real Estate) decisions should not simply deal with the management of individual facilities, but should especially be concerned with the relationships that a facility has with the corporate business strategy and with the larger real estate markets. Both the practice and the research of CRE management have historically tended to emphasize real estate issues and ignore the corporation’s business issues, causing real estate strategies to be disconnected from the goal and priorities of the corporation’s senior management. With regard to office cycles, a large number of econometric models have been proposed during the last 20 years. However, evidence from historical data and previous research in the field of real estate forecasting seem to agree only on one thing: the existence of interconnected property cycles that are concentrated on vacancy rates (demand). Vacancy also represents the linkage between the inadequacy of existing CRE strategies and the inability of existing econometric models to correctly forecast office rent cycles. Business cycles, across different industry sectors, have decreased from 5-7 years to 1-3 years today, yet corporations are still entering into leases of 5-10 years, causing hidden vacancy levels to rise. Possibly, once CRE strategies are totally in tune with the overall business, hidden vacancy will fade away providing forecasters with better quality data. The aim of this paper is not to investigate whether and when the supply-side will eventually evolve to provide flexible occupancy arrangements to accommodate corporate agility requirements, but rather to propose a general framework for corporations to improve the decision making process of their CRE executives, while emphasizing the importance of understanding the context as a precondition to effective real estate involvements.
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Despite the complication giftedness can add to the task of developing a personal sense of self during early adolescence little qualitative study is done with this group. This paper reports on a study that invited gifted young adolescents to author about their perceptions of themselves and their lives. The study used digital writing in the form of journal entries delivered by email to generate personal narratives from 12 participants over a 6 month period. With the researcher acting as an empathic listener/responder participants were supported in the expression of their thoughts and observations as authors about themselves and their lives. Findings suggest that the opportunity to self-reflect and to self express in the form of digital writing can offer a positive pathway to growth in self-understanding among gifted young adolescents. Furthermore, the involvement of an adult as an interested and responsive listener in an email relationship appears to facilitate a synergy for healthy self-disclosure.
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Australia has witnessed a continual increase in maternal employment over the past two decades, which places focus on both supply of childcare and a demand for high quality care. This study examined childcare preferences regarding the return to paid work of 124 Australian women who were expecting their first child. In contrast with most studies that have retrospective designs, the design of this study presents the perspectives of women prior to the birth of their first child-that is, before they have made a final decision about child care. This study found that the majority (78 per cent) of the women intended to re-commence work within the 12 months after the birth of their child. There were two factors that were the most salient features in their decision making-the quality of care and the personal satisfaction of engaging in paid work. The findings suggest that family friendly employment practices and access to secure, high-quality child care are key to women's secure participation in the paid workforce.
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This paper reports findings from an ongoing collaborative research project with the Financial Services Council (FSC), which contributed funding and facilitated the survey of financial planners’ clients through FSC member organisations. The article draws on the report to the FSC that was prepared by the QUT researchers, reporting findings on the initial exploratory stage of the project.1 The lyric in the title of this paper has become a catchcry for consumers dissatisfied with a range of financial services and products, and, as recent Federal Government inquiries have revealed, there is some truth to the claim. But as financial planning undergoes a series of reforms, including increased professionalism (FPA 2009) and improved quality of advice (Australian Government 2011), there are good reasons to explore the conditions under which clients report satisfaction with their financial planners; not least because the provision of effective financial planning and advice, delivered in accordance with, or transcending, the rules and norms of industry best-practice has the potential to benefit clients, not just financially, but across a number of life domains. In this paper, we report findings from an exploratory study investigating whether financial planning and advice contribute to client well-being, beyond effects on financial well-being. While anecdotal evidence supports psychological benefits such as a sense of security, little research has explored these links in any systematic or theoretically driven way. However, theory and research from cognate disciplines, such as psychology, indicate clear links between planning, goal setting and well-being that are likely to arise in the financial planning domain. Surveyed clients were asked to indicate their satisfaction with their financial advisers, the planning process and the advice they received. Clients responded to items designed to reflect key areas for financial planners in the shift towards increased professionalism, improved disclosure and greater client focus (e.g. FPA 2009). Clients also reflected on their financial situations before and after seeing their advisers, and considered the impact of their financial situations on a number of life areas including family relationships, mental health and well-being, and overall life satisfaction.
Resumo:
In the title compound, [Li(C14H36N2PSi2)(C5H5N)2], the bulky chelating monoanionic P,P-di-tert-butyl-N-trimethylsilyl-P-(trimethylsilylamino)phosphine imidate ligand and two pyridine ligands bind to Li in a pseudo-tetrahedral arrangement with twofold symmetry. The Li-N [phosphine]distance is 2.048 (5) Å, while the LiP distance is 2.520 (6) Å