379 resultados para ontogenetic niche shifts
Resumo:
The rapid growth of online social media networks like Facebook and Twitter is strongly influencing news media to engage with such networks for generating newsworthy content, accessing mass audiences for news consumption and using the platforms for news distribution. While both media’s complement each other as sources of news and information, they also compete against each other as news repositories and are observed vying for the same audiences. We call this phenomenon the competing-complementarity (C-C) engagement. To investigate the C-C relationship we use Fidler’s “mediamorphosis” concept to explain the metamorphosis of news media in the online domain. We make two contributions to Fidler’s concept by offering an additional principle “mass user migration” to address the characteristics of metamorphosis and an additional driver “transcended social engagement” to show the force that propels it. Besides, we also propose four accelerators that influence metamorphosis. Theoretical analysis of news media’s metamorphosis indicates its affinity to online social media. We apply niche and gratification theories to explain complementarity, and displacement effects on media consumption habits to trace competition between both media’s.
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The epithelium of the corneolimbus contains stem cells for regenerating the corneal epithelium. Diseases and injuries affecting the limbus can lead to a condition known as limbal stem cell deficiency (LSCD), which results in loss of the corneal epithelium, and subsequent chronic inflammation and scarring of the ocular surface. Advances in the treatment of LSCD have been achieved through use of cultured human limbal epithelial (HLE) grafts to restore epithelial stem cells of the ocular surface. These epithelial grafts are usually produced by the ex vivo expansion of HLE cells on human donor amniotic membrane (AM), but this is not without limitations. Although AM is the most widely accepted substratum for HLE transplantation, donor variation, risk of disease transfer, and rising costs have led to the search for alternative biomaterials to improve the surgical outcome of LSCD. Recent studies have demonstrated that Bombyx mori silk fibroin (hereafter referred to as fibroin) membranes support the growth of primary HLE cells, and thus this thesis aims to explore the possibility of using fibroin as a biomaterial for ocular surface reconstruction. Optimistically, the grafted sheets of cultured epithelium would provide a replenishing source of epithelial progenitor cells for maintaining the corneal epithelium, however, the HLE cells lose their progenitor cell characteristics once removed from their niche. More severe ocular surface injuries, which result in stromal scarring, damage the epithelial stem cell niche, which subsequently leads to poor corneal re-epithelialisation post-grafting. An ideal solution to repairing the corneal limbus would therefore be to grow and transplant HLE cells on a biomaterial that also provides a means for replacing underlying stromal cells required to better simulate the normal stem cell niche. The recent discovery of limbal mesenchymal stromal cells (L-MSC) provides a possibility for stromal repair and regeneration, and therefore, this thesis presents the use of fibroin as a possible biomaterial to support a three dimensional tissue engineered corneolimbus with both an HLE and underlying L-MSC layer. Investigation into optimal scaffold design is necessary, including adequate separation of epithelial and stromal layers, as well as direct cell-cell contact. Firstly, the attachment, morphology and phenotype of HLE cells grown on fibroin were directly compared to that observed on donor AM, the current clinical standard substrate for HLE transplantation. The production, transparency, and permeability of fibroin membranes were also evaluated in this part of the study. Results revealed that fibroin membranes could be routinely produced using a custom-made film casting table and were found to be transparent and permeable. Attachment of HLE cells to fibroin after 4 hours in serum-free medium was similar to that supported by tissue culture plastic but approximately 6-fold less than that observed on AM. While HLE cultured on AM displayed superior stratification, epithelia constructed from HLE on fibroin maintained evidence of corneal phenotype (cytokeratin pair 3/12 expression; CK3/12) and displayed a comparable number and distribution of ÄNp63+ progenitor cells to that seen in cultures grown on AM. These results confirm the suitability of membranes constructed from silk fibroin as a possible substrate for HLE cultivation. One of the most important aspects in corneolimbal tissue engineering is to consider the reconstruction of the limbal stem cell niche to help form the natural limbus in situ. MSC with similar properties to bone marrow derived-MSC (BM-MSC) have recently been grown from the limbus of the human cornea. This thesis evaluated methods for culturing L-MSC and limbal keratocytes using various serum-free media. The phenotype of resulting cultures was examined using photography, flow cytometry for CD34 (keratocyte marker), CD45 (bone marrow-derived cell marker), CD73, CD90, CD105 (collectively MSC markers), CD141 (epithelial/vascular endothelial marker), and CD271 (neuronal marker), immunocytochemistry (alpha-smooth muscle actin; á-sma), differentiation assays (osteogenesis, adipogenesis and chrondrogenesis), and co-culture experiments with HLE cells. While all techniques supported to varying degrees establishment of keratocyte and L-MSC cultures, sustained growth and serial propagation was only achieved in serum-supplemented medium or the MesenCult-XF„¥ culture system (Stem Cell Technologies). Cultures established in MesenCult-XF„¥ grew faster than those grown in serum-supplemented medium and retained a more optimal MSC phenotype. L-MSC cultivated in MesenCult-XFR were also positive for CD141, rarely expressed £\-sma, and displayed multi-potency. L-MSC supported growth of HLE cells, with the largest epithelial islands being observed in the presence of L-MSC established in MesenCult-XF„¥ medium. All HLE cultures supported by L-MSC widely expressed the progenitor cell marker £GNp63, along with the corneal differentiation marker CK3/12. Our findings conclude that MesenCult-XFR is a superior culture system for L-MSC, but further studies are required to explore the significance of CD141 expression in these cells. Following on from the findings of the previous two parts, silk fibroin was tested as a novel dual-layer construct containing both an epithelium and underlying stroma for corneolimbal reconstruction. In this section, the growth and phenotype of HLE cells on non-porous versus porous fibroin membranes was compared. Furthermore, the growth of L-MSC in either serum-supplemented medium or the MesenCult-XFR culture system within fibroin fibrous mats was investigated. Lastly, the co-culture of HLE and L-MSC in serum-supplemented medium on and within fibroin dual-layer constructs was also examined. HLE on porous membranes displayed a flattened and squamous monolayer; in contrast, HLE on non-porous fibroin appeared cuboidal and stratified closer in appearance to a normal corneal epithelium. Both constructs maintained CK3/12 expression and distribution of £GNp63+ progenitor cells. Dual-layer fibroin scaffolds consisting of HLE cells and L-MSC maintained a similar phenotype as on the single layers alone. Overall, the present study proposed to create a three dimensional limbal tissue substitute of HLE cells and L-MSC together, ultimately for safe and beneficial transplantation back into the human eye. The results show that HLE and L-MSC can be cultivated separately and together whilst maintaining a clinically feasible phenotype containing a majority of progenitor cells. In addition, L-MSC were able to be cultivated routinely in the MesenCult-XF® culture system while maintaining a high purity for the MSC characteristic phenotype. However, as a serum-free culture medium was not found to sustain growth of both HLE and L-MSC, the combination scaffold was created in serum-supplemented medium, indicating that further refinement of this cultured limbal scaffold is required. This thesis has also demonstrated a potential novel marker for L-MSC, and has generated knowledge which may impact on the understanding of stromal-epithelial interactions. These results support the feasibility of a dual-layer tissue engineered corneolimbus constructed from silk fibroin, and warrant further studies into the potential benefits it offers to corneolimbal tissue regeneration. Further refinement of this technology should explore the potential benefits of using epithelial-stromal co-cultures with MesenCult-XF® derived L-MSC. Subsequent investigations into the effects of long-term culture on the phenotype and behaviour of the cells in the dual-layer scaffolds are also required. While this project demonstrated the feasibility in vitro for the production of a dual-layer tissue engineered corneolimbus, further studies are required to test the efficacy of the limbal scaffold in vivo. Future in vivo studies are essential to fully understand the integration and degradation of silk fibroin biomaterials in the cornea over time. Subsequent experiments should also investigate the use of both AM and silk fibroin with epithelial and stromal cell co-cultures in an animal model of LSCD. The outcomes of this project have provided a foundation for research into corneolimbal reconstruction using biomaterials and offer a stepping stone for future studies into corneolimbal tissue engineering.
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Purpose Over the past decade, the Queensland wine industry has experienced a greater percentage growth than the Australian national average. The aim of the research undertaken for this article is to identify specific national and international strategies that have allowed the industry to achieve this level of growth. Design/methodology/approach The study involved a quantitative survey of all Queensland wineries at the time (n=101), using a five-point Likert-scaled questionnaire with questions developed from the literature, together with a small-scale qualitative survey involving in-depth interviews of winery managers and industry leaders. Findings The findings indicated that key strategies in the domestic sector included a focus on cellar door sales combined with establishing links with the tourism industry, together with an incremental expansion of domestic markets. For the international sector, additional strategies included targeting familiar, psychically-close and niche markets in the initial stages of exporting, as well as taking advantage of firm-specific strengths and managerial competencies. Originality/value Not previously regarded as a major wine producing region of Australia, the Queensland wine industry has received limited attention in the literature, particularly the reasons for its rapid growth in recent years. The article helps to identify the strategies used by wineries in growing the industry.
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Gazelles, or very rapidly growing firms, are important because they contribute disproportionately to economic growth. There is a concern that some of these firms pursue growth too aggressively resulting in lower subsequent performance. We investigate the relationship between growth and subsequent profitability for gazelle firms, and how this is moderated by firm strategy. Previous empirical research regarding the growth-profitability relationship for firms in general is rather inconclusive, with only one study specifically investigating gazelle firms. Likewise, there are theoretical arguments both for and against growth leading to profitability that equally apply to gazelle firms. Further, while contingency theory might suggest the relationship depends on the firm’s strategy, earlier studies have not investigated this relationship. We address these questions using longitudinal data (seven years) for a sample of 964 Danish Gazelle firms. Our study finds a clear positive relationship between growth and subsequent profitability among gazelle firms. Moreover, this relationship is stronger for firms pursuing a broad market strategy rather than a focus or niche strategy. An important managerial implication is that the growth strategy should be clearly integrated with the general strategic orientation of the firm.
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Iran as a developing country faces many considerable shortages of both physical learning environment and inefficient budget to resolve this shortage. Today, Iran needs a $28 billion budget to add 23,000 schools to the existing 120,000 schools to be able to omit two shifts schools [1], [2]. Moreover, the standard learning space is 6-8 square meter per student, while this rate for big cities in Iran is about one square meter per student [1]. This decrease the time students spend in schools. In addition, the education approach in k-12 and higher education is still teacher-centered based and needs to be contemporized with educational, cultural, and technological changes.
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For over half a century art directors within the advertising industry have been adapting to the changes occurring in media, culture and the corporate sector, toward enhancing professional performance and competitiveness. These professionals seldom offer explicit justification about the role images play in effective communication. It is uncertain how this situation affects advertising performance, because advertising has, nevertheless, evolved in parallel to this as an industry able to fabricate new opportunities for itself. However, uncertainties in the formalization of art direction knowledge restrict the possibilities of knowledge transfer in higher education. The theoretical knowledge supporting advertising art direction has been adapted spontaneously from disciplines that rarely focus on specific aspects related to the production of advertising content, like, for example: marketing communication, design, visual communication, or visual art. Meanwhile, in scholarly research, vast empirical knowledge has been generated about advertising images, but often with limited insight into production expertise. Because art direction is understood as an industry practice and not as an academic discipline, an art direction perspective in scholarly contributions is rare. Scholarly research that is relevant to art direction seldom offers viewpoints to help understand how it is that research outputs may specifically contribute to art direction practices. This thesis is dedicated to formally understanding the knowledge underlying art direction and using it to explore models for visual analysis and knowledge transfer in higher education. The first three chapters of this thesis offer, firstly, a review of practical and contextual aspects that help define art direction, as a profession and as a component in higher education; secondly, a discussion about visual knowledge; and thirdly, a literature review of theoretical and analytic aspects relevant to art direction knowledge. Drawing on these three chapters, this thesis establishes explicit structures to help in the development of an art direction curriculum in higher education programs. Following these chapters, this thesis explores a theoretical combination of the terms ‘aesthetics’ and ‘strategy’ as foundational notions for the study of art direction. The theoretical exploration of the term ‘strategic aesthetics’ unveils the potential for furthering knowledge in visual commercial practices in general. The empirical part of this research explores ways in which strategic aesthetics notions can extend to methodologies of visual analysis. Using a combination of content analysis and of structures of interpretive analysis offered in visual anthropology, this research discusses issues of methodological appropriation as it shifts aspects of conventional methodologies to take into consideration paradigms of research that are producer-centred. Sampled out of 2759 still ads from the online databases of Cannes Lions Festival, this study uses an instrumental case study of love-related advertising to facilitate the analysis of content. This part of the research helps understand the limitations and functionality of the theoretical and methodological framework explored in the thesis. In light of the findings and discussions produced throughout the thesis, this project aims to provide directions for higher education in relation to art direction and highlights potential pathways for further investigation of strategic aesthetics.
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Many ecosystems worldwide are dominated by introduced plant species, leading to loss of biodiversity and ecosystem function. A common but rarely tested assumption is that these plants are more abundant in introduced vs. native communities, because ecological or evolutionary-based shifts in populations underlie invasion success. Here, data for 26 herbaceous species at 39 sites, within eight countries, revealed that species abundances were similar at native (home) and introduced (away) sites – grass species were generally abundant home and away, while forbs were low in abundance, but more abundant at home. Sites with six or more of these species had similar community abundance hierarchies, suggesting that suites of introduced species are assembling similarly on different continents. Overall, we found that substantial changes to populations are not necessarily a pre-condition for invasion success and that increases in species abundance are unusual. Instead, abundance at home predicts abundance away, a potentially useful additional criterion for biosecurity programmes.
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Non-state insurgent actors are too weak to compel powerful adversaries to their will, so they use violence to coerce. A principal objective is to grow and sustain violent resistance to the point that it either militarily challenges the state, or more commonly, generates unacceptable political costs. To survive, insurgents must shift popular support away from the state and to grow they must secure it. State actor policies and actions perceived as illegitimate and oppressive by the insurgent constituency can generate these shifts. A promising insurgent strategy is to attack states in ways that lead angry publics and leaders to discount the historically established risks and take flawed but popular decisions to use repressive measures. Such decisions may be enabled by a visceral belief in the power of coercion and selective use of examples of where robust measures have indeed suppressed resistance. To avoid such counterproductive behaviours the cases of apparent 'successful repression' must be understood. This thesis tests whether robust state action is correlated with reduced support for insurgents, analyses the causal mechanisms of such shifts and examines whether such reduction is because of compulsion or coercion? The approach is founded on prior research by the RAND Corporation which analysed the 30 insurgencies most recently resolved worldwide to determine factors of counterinsurgent success. This new study first re-analyses their data at a finer resolution with new queries that investigate the relationship between repression and insurgent active support. Having determined that, in general, repression does not correlate with decreased insurgent support, this study then analyses two cases in which the data suggests repression seems likely to be reducing insurgent support: the PKK in Turkey and the insurgency against the Vietnamese-sponsored regime after their ousting of the Khmer Rouge. It applies 'structured-focused' case analysis with questions partly built from the insurgency model of Leites and Wolf, who are associated with the advocacy of US robust means in Vietnam. This is thus a test of 'most difficult' cases using a 'least likely' test model. Nevertheless, the findings refute the deterrence argument of 'iron fist' advocates. Robust approaches may physically prevent effective support of insurgents but they do not coercively deter people from being willing to actively support the insurgency.
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Quality oriented management systems and methods have become the dominant business and governance paradigm. From this perspective, satisfying customers’ expectations by supplying reliable, good quality products and services is the key factor for an organization and even government. During recent decades, Statistical Quality Control (SQC) methods have been developed as the technical core of quality management and continuous improvement philosophy and now are being applied widely to improve the quality of products and services in industrial and business sectors. Recently SQC tools, in particular quality control charts, have been used in healthcare surveillance. In some cases, these tools have been modified and developed to better suit the health sector characteristics and needs. It seems that some of the work in the healthcare area has evolved independently of the development of industrial statistical process control methods. Therefore analysing and comparing paradigms and the characteristics of quality control charts and techniques across the different sectors presents some opportunities for transferring knowledge and future development in each sectors. Meanwhile considering capabilities of Bayesian approach particularly Bayesian hierarchical models and computational techniques in which all uncertainty are expressed as a structure of probability, facilitates decision making and cost-effectiveness analyses. Therefore, this research investigates the use of quality improvement cycle in a health vii setting using clinical data from a hospital. The need of clinical data for monitoring purposes is investigated in two aspects. A framework and appropriate tools from the industrial context are proposed and applied to evaluate and improve data quality in available datasets and data flow; then a data capturing algorithm using Bayesian decision making methods is developed to determine economical sample size for statistical analyses within the quality improvement cycle. Following ensuring clinical data quality, some characteristics of control charts in the health context including the necessity of monitoring attribute data and correlated quality characteristics are considered. To this end, multivariate control charts from an industrial context are adapted to monitor radiation delivered to patients undergoing diagnostic coronary angiogram and various risk-adjusted control charts are constructed and investigated in monitoring binary outcomes of clinical interventions as well as postintervention survival time. Meanwhile, adoption of a Bayesian approach is proposed as a new framework in estimation of change point following control chart’s signal. This estimate aims to facilitate root causes efforts in quality improvement cycle since it cuts the search for the potential causes of detected changes to a tighter time-frame prior to the signal. This approach enables us to obtain highly informative estimates for change point parameters since probability distribution based results are obtained. Using Bayesian hierarchical models and Markov chain Monte Carlo computational methods, Bayesian estimators of the time and the magnitude of various change scenarios including step change, linear trend and multiple change in a Poisson process are developed and investigated. The benefits of change point investigation is revisited and promoted in monitoring hospital outcomes where the developed Bayesian estimator reports the true time of the shifts, compared to priori known causes, detected by control charts in monitoring rate of excess usage of blood products and major adverse events during and after cardiac surgery in a local hospital. The development of the Bayesian change point estimators are then followed in a healthcare surveillances for processes in which pre-intervention characteristics of patients are viii affecting the outcomes. In this setting, at first, the Bayesian estimator is extended to capture the patient mix, covariates, through risk models underlying risk-adjusted control charts. Variations of the estimator are developed to estimate the true time of step changes and linear trends in odds ratio of intensive care unit outcomes in a local hospital. Secondly, the Bayesian estimator is extended to identify the time of a shift in mean survival time after a clinical intervention which is being monitored by riskadjusted survival time control charts. In this context, the survival time after a clinical intervention is also affected by patient mix and the survival function is constructed using survival prediction model. The simulation study undertaken in each research component and obtained results highly recommend the developed Bayesian estimators as a strong alternative in change point estimation within quality improvement cycle in healthcare surveillances as well as industrial and business contexts. The superiority of the proposed Bayesian framework and estimators are enhanced when probability quantification, flexibility and generalizability of the developed model are also considered. The empirical results and simulations indicate that the Bayesian estimators are a strong alternative in change point estimation within quality improvement cycle in healthcare surveillances. The superiority of the proposed Bayesian framework and estimators are enhanced when probability quantification, flexibility and generalizability of the developed model are also considered. The advantages of the Bayesian approach seen in general context of quality control may also be extended in the industrial and business domains where quality monitoring was initially developed.
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As the economic and social benefits of creative industries development become increasingly visible, policymakers worldwide are working to create policy drivers to ensure that certain places become or remain ‘creative places’. Richard Florida’s work has become particularly influential among policymakers, as has Landry’s. But as the first wave of creative industrial policy development and implementation wanes, important questions are emerging. It is by now clear that an ‘ideal creative place’ has arisen from creative industries policy and planning literature, and that this ideal place is located in inner cities. This article shifts its focus away from the inner city to where most Australians live: the outer suburbs. It reports on a qualitative research study into the practices of outer-suburban creative industries workers in Redcliffe, Australia. It argues that the accepted geography of creative places requires some recalibration once the material and experiential aspects of creative places are taken into account.
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While the literature points to significant shifts in young peoples’ labour market participation and the social, economic and political context in which this has occurred, it tells us little about whether and in what sense young people can be considered as industrial citizens. We explored the notion of youth citizenship using data derived from 48 focus groups conducted with 216 young people (13-16 years of age) at 19 high schools in Australia. The findings reveal the ways in which several key dimensions of industrial citizenship come to be shaped and have implications for addressing the vulnerability of youth in employment and informing policy and action.
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Abstract: This study explores the contradictions and ambivalences experienced by a working artist at a time when her age, her gender, and broader cultural shifts are all potential obstacles or liabilities to creative flourishing. It is the product of practice-led research into the creative process from the perspective of the female "late bloomer". In this phrase, I have in mind the mature-aged woman who is, in mid-life, suddenly seized with inspiration and fired with creative energy. At its heart is the question: If an Elizabeth Jolley were in our midst today, would we hear from her? The result is a full-length libretto and accompanying exegetical binoculars in the form of a Preface and an Afterword. The creative work, Things That Fall Over (TTFO) is conceived in two parts: a libretto and oratorio for performance. It begins as a play, but over three acts and into a coda, the work becomes something entirely other - an (anti-) musical. The work grew from a personal interest in the nexus between women, ageing and creative practice, via investigation into the oeuvre of two Australian artists, Elizabeth Jolley, author, first published at age 53, and Rosalie Gascoigne, sculptor, first exhibited at 58. A second strand of the research grew from a fascination for the stage musical, especially in its more alternative modes as in the hands of Stephen Sondheim, or in more provocative manifestations as witnessed in recent Tony Award winners Avenue Q and The Book of Mormon. Contextually, this research is conducted at a time when anecdotal evidence suggests that women’s work in the performing arts and in literature is being pushed to the margins after a late twentieth century Golden Age on page and stage. Using hybrid practice-led methodologies - bricolage, log-keeping - and working within queer and feminist paradigms, this study seeks to counter that push with a new work that is all-female, part-pantomime, part monstrous allegory. In illuminating the creative process of a mature-aged playwright it concludes that hybrid and interstitial forms still offer an inclusive and democratic space in which voices that may otherwise be muted will continue to be heard.
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Real estate markets in Chinese cities are in transition. Advertising for new developments in these markets often reflects changing city aspirations and branding rather than environmental and social experience. This paper investigates real estate marketing as a site of potential ethical transformation of values related to new urban development. It uses Kenneth Burke’s rhetorical analysis as an approach to coding real estate representations from in-flight magazine advertisements as a means of capturing environmental and social viewpoints in China during 2008 - 2009. Both Chinese and foreign participants coded representations into four code modalities. These were based on anthropocentric - non-anthropocentric environmental orientations and nationalistic - universal social orientations. The results suggested that new developments in China are more likely to be understood as based on environmental resource use for continued national economic expansion rather than for a more sustainable world. Emerging patterns in coded representations have opened up the possibility of greater social choices that were however difficult to unambiguously decode from Chinese real estate advertising. From this it is concluded that it may take some time before real estate demand shifts in response to representations of Chinese eco-cities being promoted by Chinese policy makers in the 2000s.
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This paper will consider some of the wider contextual and policy questions arising out of four major public inquiries that took place in Australia over 2011–2012: the Convergence Review, the National Classification Scheme Review, the Independent Media Inquiry (Finkelstein Review) and the National Cultural Policy. This paper considers whether we are now witnessing a ‘convergent media policy moment’ akin to the ‘cultural policy moment’ theorized by Australian cultural researchers in the early 1990s, and the limitations of various approaches to understanding policy – including critiques of neoliberalism – in understanding such shifts. It notes the rise of ‘soft law’ as a means of addressing the challenges of regulatory design in an era of rapid media change, with consideration of two cases: the approach to media influence taken in the Convergence Review, and the concept of ‘deeming’ developed in the National Classification Scheme Review.
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Pronounced phenotypic shifts in island populations are typically attributed to natural selection, but reconstructing heterogeneity in long-term selective regimes remains a challenge. We examined a scenario of divergence proposed for species colonizing a new environment, involving directional selection with a rapid shift to a new optimum and subsequent stabilization. We provide some of the first empirical evidence for this model of evolution using morphological data from three timescales in an island bird, Zosterops lateralis chlorocephalus. In less than four millennia since separation from its mainland counterpart, a substantial increase in body size has occurred and was probably achieved in fewer than 500 generations after colonization. Over four recent decades, morphological traits have fluctuated in size but showed no significant directional trends, suggesting maintenance of a relatively stable phenotype. Finally, estimates of contemporary selection gradients indicated generally weak directional selection. These results provide a rare description of heterogeneity in long-term natural regimes, and caution that observations of current selection may be of limited value in inferring mechanisms of past adaptation due to a lack of constancy even over short time-frames.