953 resultados para peacock flower
Resumo:
We report a high-quality draft genome sequence of the domesticated apple (Malus × domestica). We show that a relatively recent (>50 million years ago) genome-wide duplication (GWD) has resulted in the transition from nine ancestral chromosomes to 17 chromosomes in the Pyreae. Traces of older GWDs partly support the monophyly of the ancestral paleohexaploidy of eudicots. Phylogenetic reconstruction of Pyreae and the genus Malus, relative to major Rosaceae taxa, identified the progenitor of the cultivated apple as M. sieversii. Expansion of gene families reported to be involved in fruit development may explain formation of the pome, a Pyreae-specific false fruit that develops by proliferation of the basal part of the sepals, the receptacle. In apple, a subclade of MADS-box genes, normally involved in flower and fruit development, is expanded to include 15 members, as are other gene families involved in Rosaceae-specific metabolism, such as transport and assimilation of sorbitol.
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MADS-box genes similar to Arabidopsis SHORT VEGETATIVE PHASE (SVP) have been implicated in the regulation of flowering in annual species and bud dormancy in perennial species. Kiwifruit (Actinidia spp.) are woody perennial vines where bud dormancy and out-growth affect flower development. To determine the role of SVP-like genes in dormancy and flowering of kiwifruit, four MADS-box genes with homology to Arabidopsis SVP, designated SVP1, SVP2, SVP3, and SVP4, have been identified and analysed in kiwifruit and functionally characterized in Arabidopsis. Phylogenetic analysis indicate that these genes fall into different sub-clades within the SVP-like gene group, suggesting distinct functions. Expression was generally confined to vegetative tissues, and increased transcript accumulation in shoot buds over the winter period suggests a role for these genes in bud dormancy. Down-regulation before flower differentiation indicate possible roles as floral repressors. Over-expression and complementation studies in Arabidopsis resulted in a range of floral reversion phenotypes arising from interactions with Arabidopsis MADS-box proteins, but only SVP1 and SVP3 were able to complement the svp mutant. These results suggest that the kiwifruit SVP-like genes may have distinct roles during bud dormancy and flowering.
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Each September since 1983 in the rural Shire of Ravensthorpe, Western Australia, volunteers collect samples of up to 700 wildfl ower species which are then displayed in the Ravensthorpe Senior Citizens Centre from 9.00 am to 4.00 pm daily over a two-week period. This chapter offers an ethnographic interpretation of this enduring annual event focusing on the 25th show held in 2007. The study contributes to understanding the complex and nuanced role of local wildflower shows in shaping and supporting rural senses of place and of community. Importantly, this particular type of festival, and more specifically this local instance, foregrounds a less-remarked aspect of festivals, namely the (re)production and celebration of place-specific knowledge through validations of, and interconnections between, scientific flower classification and emotive experience. This feature, encapsulated in Laurel Lamperd’s poem above, invites consideration of the ways in which local place knowledge and the simultaneous (re)production of ‘place’ are constituted by a complex layering of rational, objective ways of knowing and those which emphasize emotions, aesthetics and memories. This rural wildflower show not only mobilises both the rational and the emotional in ‘making sense of the world’ for local residents and for tourists, but also offers insights into the production of place as constituted in and through relations between humans and non-human life forms (Cloke & Jones, 2001; Conradson, 2005; see also Chapter 6).
Resumo:
SVP-like MADS domain transcription factors have been shown to regulate flowering time and both inflorescence and flower development in annual plants, while having effects on growth cessation and terminal bud formation in perennial species. Previously, four SVP genes were described in woody perennial vine kiwifruit (Actinidia spp.), with possible distinct roles in bud dormancy and flowering. Kiwifruit SVP3 transcript was confined to vegetative tissues and acted as a repressor of flowering as it was able to rescue the Arabidopsis svp41 mutant. To characterize kiwifruit SVP3 further, ectopic expression in kiwifruit species was performed. Ectopic expression of SVP3 in A. deliciosa did not affect general plant growth or the duration of endodormancy. Ectopic expression of SVP3 in A. eriantha also resulted in plants with normal vegetative growth, bud break, and flowering time. However, significantly prolonged and abnormal flower, fruit, and seed development were observed, arising from SVP3 interactions with kiwifruit floral homeotic MADS-domain proteins. Petal pigmentation was reduced as a result of SVP3-mediated interference with transcription of the kiwifruit flower tissue-specific R2R3 MYB regulator, MYB110a, and the gene encoding the key anthocyanin biosynthetic step, F3GT1. Constitutive expression of SVP3 had a similar impact on reproductive development in transgenic tobacco. The flowering time was not affected in day-neutral and photoperiod-responsive Nicotiana tabacum cultivars, but anthesis and seed germination were significantly delayed. The accumulation of anthocyanin in petals was reduced and the same underlying mechanism of R2R3 MYB NtAN2 transcript reduction was demonstrated.
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Two BRCA2-like sequences are present in the Arabidopsis genome. Both genes are expressed in flower buds and encode nearly identical proteins, which contain four BRC motifs. In a yeast two-hybrid assay, the Arabidopsis Brca2 proteins interact with Rad51 and Dmc1. RNAi constructs aimed at silencing the BRCA2 genes at meiosis triggered a reproducible sterility phenotype, which was associated with dramatic meiosis alterations. We obtained the same phenotype upon introduction of RNAi constructs aimed at silencing the RAD51 gene at meiosis in dmc1 mutant plants. The meiotic figures we observed strongly suggest that homologous recombination is highly disturbed in these meiotic cells, leaving aberrant recombination events to repair the meiotic double-strand breaks. The 'brca2' meiotic phenotype was eliminated in spo11 mutant plants. Our experiments point to an essential role of Brca2 at meiosis in Arabidopsis. We also propose a role for Rad51 in the dmc1 context.
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Current national reforms in Australian higher education have prioritised efforts to reduce educational disadvantage within a vernacular expression of neoliberal education policy. Student-equity policy in universities is enmeshed in a set of competitive student recruitment relations. This raises practice-based tensions as universities strive to meet specific institutional targets for low-socio-economic status (SES) and Indigenous student participation, whilst broadening participation more generally within the sector. This paper seeks empirically to trace the activation and appropriation of federal policy through two sites of higher education policy practices: a state government-sponsored equity practitioner body and two differently positioned universities, Dawson and McIllwraith, as they engage with low-SES schools. Working together Dorothy Smith’s insights into the textually mediated activation of local practices, Levinson and colleagues’ concept of the local appropriation of authorised policy, and Bourdieu’s notion of the contested field, we demonstrate that the generation of state level and institutionally specific policies for student-equity practices not only articulates to federal policy, but also appropriates the ruling relations of mandated policy. Further, the scope of these creative local appropriations is organised within a hierarchical academic field through which particular institutional imperatives, as well as the needs of low-SES students, are negotiated. The analysis demonstrates the vernacularisation of policy in the national rearticulation of global discourses, in appropriation at the level of the state body and in the practices of equity workers.
Neoliberal social inclusion? The agenda of the Australian Universities Community Engagement Alliance
Resumo:
University–community engagement (UCE) represents a hybrid discourse and a set of practices within contemporary higher education. As a modality of research and teaching, ‘engagement’ denotes the process of universities forming partnerships with external communities for the promised generation of mutually beneficial and socially responsive knowledge, leading to enhanced economic, social and cultural developments. A critical discourse analysis (Fairclough 2003. Analysing Discourse: Textual analysis for social research. London: Routledge) of the Australian Universities Community Engagement Alliance’s (AUCEA) ‘Position Paper’(2008 Universities and community engagement (Position paper 2008–2010)), as reported in this article, suggests that its uneasy synthesis of neoliberal, social inclusion and civic engagement discourses into a hybrid UCE discourse semantically privileges neoliberal forms of engagement. Perhaps, as a result, the AUCEA seems to have missed an opportunity to influence the Australian ‘widening participation’ debate on securing access and opportunity for marginalised students at universities and building social and cultural capital within their communities of origin.
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This chapter examines the process of “transformative learning” for the 2008 cohort of the St. Thomas More College–Intercordia Canada (STM/IC) international community service-learning program. My primary data comes from the eight students who were part of that cohort, when I was their program coordinator. That data later became the heart of my Master’s thesis and was approved by the Research Ethics Office of the University of Saskatchewan. In this chapter I focus on three of those eight participants, outlining the critical elements of their experiences that were conducive to their transformative learning. To be sure, my sample size is too small to draw generalizable conclusions, but the quality of information I received from these students and their colleagues, coupled with the follow-up conversations I had with other educators and with the accompanying literature, supports the value of reflecting at length here about these students’ comments. I have chosen to highlight the experiences of these three participants because together they provide a range of experiences that best enables an analysis of the conditions that both did and did not lead to transformative learning. This case study suggests that transformative learning occurs through: the dynamics of vulnerability, a discovery of persisting differences within inter-personal relationships, and an experience of welcome and hospitality in the host environment. In contrast to other studies that focus on the enhanced capacities, skills and subsequent employability of participants through international education, transformative learning for these students required a relinquishing of securities, a disorientation and critical interrogation of the self, and enhanced receptivity to the newly recognized Other. Moreover, consistent with the critical-humanistic educational philosophy shared in different ways by the participants of the STM/IC program, this study suggests that international community service-learning can most responsibly contribute to good global citizenship through the construction of relationships of solidarity across difference.
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The conventional approach to setting a milling unit is essentially based on the desire to achieve a particular bagasse moisture content or fibre fill in each nip of the mill. This approach relies on the selection of the speed at which the mill will operate for the selected fibre rate. There is rarely any checking that the selected speed or the selected fibre fill is achieved and the same set of assumptions is generally carried over to use again in the next year. The conventional approach largely ignores the fact that the selection of mill settings actually determines the speed at which the mill will operate. Making an adjustment with the intent of changing the performance of the mill often also changes the speed of the mill as an unintended consequence. This paper presents an alternative approach to mill setting. The approach discussed makes use of mill feeding theory to define the relationship between fibre rate, mill speed and mill settings and uses that theory to provide an alternative means of determining the settings in some nips of the mill. Mill feeding theory shows that, as the feed work opening reduces, roll speed increases. The theory also shows that there is an optimal underfeed opening and Donnelly chute exit opening that will minimise roll speed and that the current South African guidelines appear to be well away from those optimal values.
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This Australian Indigenous creactive work and its Treatise promote ways of thinking about practice and research that extend well beyond the current discourse. It invites re-thinking on how research can be practice-led in new ways, and what that might mean for future students. When discussing the challenges of today, this work signifies how "Western Style" thinking and theory is wanting in so many ways. It engages a new dynamic and innovative way of theorising, encouraging future students to apply their full capacity of energy and wisdom. (Extract from examiners' reports.)
Influence of carbohydrate source on the in vitro flowering of Sturt's Desert Pea (Swainsona formosa)
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Transfusion-related acute lung injury (TRALI) has been the leading cause of transfusion-related morbidity and mortality in the UK and the USA in recent years. A threshold mechanism of TRALI has been proposed in which both patient factors (type and/or severity of clinical insult) and blood product factors (strength and/or concentration of antibodies or biological response modifiers) interact to surpass a threshold for TRALI development (Bux et al. Br J Haematol; 2007; 136: 788-99). The risk of developing antibody-mediated TRALI has been minimised by the introduction of risk-reduction strategies such as limiting the use of plasma from female donors. In contrast, there are no strategies currently in place to mitigate the development of non-antibody mediated TRALI as the mechanisms remain largely undefined. Previous studies have implicated non-polar lipids such as arachidonic acid and various species of hydroxyeicosatetranoic acid (HETE) in the development of non-antibody mediated TRALI (Silliman et al. Transfusion; 2011; 51: 2549-54), however the contribution of these lipids to the development of an inflammatory response in TRALI is poorly understood.
Numerical investigation of motion and deformation of a single red blood cell in a stenosed capillary
Resumo:
It is generally assumed that influence of the red blood cells (RBCs) is predominant in blood rheology. The healthy RBCs are highly deformable and can thus easily squeeze through the smallest capillaries having internal diameter less than their characteristic size. On the other hand, RBCs infected by malaria or other diseases are stiffer and so less deformable. Thus it is harder for them to flow through the smallest capillaries. Therefore, it is very important to critically and realistically investigate the mechanical behavior of both healthy and infected RBCs which is a current gap in knowledge. The motion and the steady state deformed shape of the RBCs depend on many factors, such as the geometrical parameters of the capillary through which blood flows, the membrane bending stiffness and the mean velocity of the blood flow. In this study, motion and deformation of a single two-dimensional RBC in a stenosed capillary is explored by using smoothed particle hydrodynamics (SPH) method. An elastic spring network is used to model the RBC membrane, while the RBC's inside fluid and outside fluid are treated as SPH particles. The effect of RBC's membrane stiffness (kb), inlet pressure (P) and geometrical parameters of the capillary on the motion and deformation of the RBC is studied. The deformation index, RBC's mean velocity and the cell membrane energy are analyzed when the cell passes through the stenosed capillary. The simulation results demonstrate that the kb, P and the geometrical parameters of the capillary have a significant impact on the RBCs' motion and deformation in the stenosed section.