101 resultados para Adventitious roots


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Modern genetic research holds out the promise of a bold new future in which humanity has identified and conquered the genetic roots of many diseases. Genetic science also promises to shed light on who we are, what it is that makes us tick, what it is that makes us the way we are — in short, what it is that makes us human. Yet while genetics are a potential saviour (saving us from disease), it also appears as a threat that at the extremes appears to be the stuff of our worst nightmares, such as the prospect, probably more imagined than real, of rows of cloned individuals. The new genetics hold out the promise that through genetics we will be able to determine what we are, a promise that is simultaneously appealing and terrifying. This chapter discusses the cloning of people and parts, the law’s response to cloning, genetics and diversity, a framework for law reform.

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Banana bunchy top disease (BBTD) caused by banana bunchy top virus (BBTV) was radioactively detected by nucleic acid hybridization techniques. Results showed that, 32P-labelled insert of pBT338 was hybridized with nucleic acid extracts from BBTV-infected plants from Egypt and Australia but not with those from CMV-infected plants from Egypt. Results revealed that BBTV was greatly detected in midrib, roots, meristem, corm, leaves and pseudostem respectively. BBTV was also detected in symptomless young plants prepared from diseased plant materials grown under tissue culture conditions but was not present in those performed from healthy plant materials. The sensitivity of dot blot and Southern blot hybridizations for the detection of BBTV was also performed for the detection of BBTV.

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"For myself, I am an optimist - it does not seem to be much use to be anything else". Winston Churchill Optimism has its modern roots in philosophy dating back to the 17th century in the writings of philosophers such as Descartes and Voltaire (Domino & Conway, 2001). Previous to these philosophical writings, the concept of optimism was revealed in the teaching of many of the great spiritual traditions such as Buddhism and Christianity (Miller, Richards, & Keller, 2001). In the 20th century, optimism became defined in juxtaposition to pessimism, sometimes conceptualized as a bipolar unidimensional construct and by others as two related but separate constructs (Garber, 2000). Contemporary models (Scheier & Carver, 1985; Seligman, 1991) have increasingly focused on distinguishing optimism-pessimism as a general dispositional orientation, as described by expectancy theory, and as an explanatory process, described by explanatory style theory.

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Managing sewer blockages represents a significant operational challenge for water utilities. In Australia, company-level blockage rates are used to compare the effectiveness of the management strategies of different utilities. Anecdotal evidence suggests this may not be a fair basis for comparison because blockages are influenced by a range of factors beyond management control and that vary from company to company. This issue was investigated as part of a broader research effort on sewer blockage management undertaken in conjunction with the Water Services Association of Australia (WSAA) and its members. A Web-based survey was used to collate expert opinion on factors that influence blockage rate. The identified factors were then investigated in an exploratory analysis of blockage-related data provided by two participating utilities, supported by literature reviews. The results indicate that blockage rate is influenced by a range of factors, including asset attributes, climatic conditions, water consumption, and soil type. Since these factors vary from utility to utility, this research supports the assertion that company-level blockage rate is not in itself an appropriate metric for comparing management effectiveness.

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Sewer main chokes (blockages) are a key performance indicator for Australian water utilities. Blockages caused by tree roots often result in wastewater overflow posing an environmental and health risk and also requiring service interruptions to repair asset. The purpose of the research project outlined in this paper was to understand the role of environmental parameters, in particular soil type and tree density, in determining the propensity of a sewer to become blocked. The paper demonstrates the application of spatial analysis to inform and communicate the results of the analysis. GIS was used to explore the relationship between tree density and previously recorded sewer blockages for a Melbourne utility. Initial results from the research reveal a relationship between increased tree densities and occurrence of sewer blockages. An improved understanding of the influence of environmental parameters on the inherent risk of sewer blockage will enable asset managers to identify those assets requiring proactive management in order to minimise service interruptions, repairs and environmental impacts.

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Salinity is a major threat to sustainable agriculture worldwide. Plant NHX exchangers play an important role in conferring salt tolerance under salinity stress. In this study, a vacuolar Na+/H+ antiporter gene VrNHX1 (Genbank Accession No. JN656211.1) from mungbean (Vigna radiata) was introduced into cowpea (Vigna unguiculata) by the Agrobacterium tumefaciens-mediated transformation method. Polymerase chain reaction and Southern blot hybridization confirmed the stable integration of VrNHX1 into the cowpea genome. Comparative expression analysis by semi-quantitative RT-PCR revealed higher expression of VrNHX1 in transgenic cowpea plants than wild-type. Under salt stress conditions, T2 transgenic 35S:VrNHX1 cowpea lines exhibited higher tolerance to 200 mM NaCl treatment than wild-type. Furthermore, T2 transgenic 35S:VrNHX1 lines maintained a higher K+/Na+ ratio in the aerial parts under salt stress and accumulated higher [Na+] in roots than wild-type. Physiological analysis revealed lower levels of lipid peroxidation, hydrogen peroxide and oxygen radical production but higher levels of relative water content and proline, ascorbate and chlorophyll contents in T2 transgenic 35S:VrNHX1 lines.

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Acid sulfate soils (ASS) is a stress factor that is responsible for the failure of some mangrove restoration projects, including abandoned aquaculture ponds converted from mangrove ecosystems. Through experimental and field studies, this research provides a better understanding of the biogeochemistry of ASS disturbance and the response of mangrove seedlings (Rhizophoraceae) under high metal levels and acidic conditions. This study found that mangrove restorations under ASS disturbance can work but with lower numbers of survived seedlings. To prevent toxicity under high levels of metal, seedlings retained metals in their roots and sparingly distributed them into aerial parts with low mobility. The presence of high levels of potential acidity parameters would allow pyrite to oxidise, thus increasing metal levels and acidity, which in turn affected the survival and growth of the seedlings.

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“Children are not little adults.” Almost all aspects of children's health including clinical trials and drug development are poor cousins of adult health. Over the years, pediatricians worldwide caution against blind extrapolation of adult data to children as it may result in considerable harm [1,2]. Also, it is increasingly recognized that the roots of many chronic diseases in adulthood stem from childhood and tackling health issues in children lead to improved health in adults [3,4]. Furthermore, investment in early childhood has long-term benefits in adults not only in health but also in other aspects of life such as education and crime reduction [4,5]. Arguably, health at birth is the single most important predictor of health in adulthood as the inequality of an infant at birth has intergenerational effects [5]. The Carolina Abecedarian Project showed that early childhood programs that are of high quality result in substantial societal benefits (e.g., reduction of crime, increased earnings, better education) [4,5]. A recent publication from this project found that this benefit also translated into improved adult health outcomes [4]. In a randomized trial, Campbell and colleagues described that disadvantaged children who were randomized to the intervention group (early education, health screenings and nutrition program) had significantly lower rates of metabolic syndrome, obesity and hypertension, when aged in their mid-30s, compared with the control group [4]...

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Videogame control interfaces continue to evolve beyond their traditional roots, with devices encouraging more natural forms of interaction growing in number and pervasiveness. Yet little is known about their true potential for intuitive use. This paper proposes methods to leverage existing intuitive interaction theory for games research, specifically by examining different types of naturally mapped control interfaces for videogames using new measures for previous player experience. Three commercial control devices for a racing game were categorised using an existing typology, according to how the interface maps physical control inputs with the virtual gameplay actions. The devices were then used in a within-groups (n=64) experimental design aimed at measuring differences in intuitive use outcomes. Results from mixed design ANOVA are discussed, along with implications for the field.

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Early childhood education and care (ECEC) has long been connected with objectives related to social justice. ECEC in Australia has its roots in philanthropic and educational reform movements, and more recently with the National Early Childhood Reform Agenda, ECEC has once more been linked to the redressing inequality and disadvantage. Drawing on extant literature, including data from two previously reported Australian studies in which leadership emerged as having a transformational impact on service delivery, this paper examines the potential of early childhood leadership to generate ‘socially just’ educational communities. With reference to critical theory, we argue that critically informed, intentional and strategic organisational leadership can play a pivotal role in creating changed circumstances and opportunities for children and families.

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This paper aims to address the ways in which drawing can be understood as the becoming-expressive of materials, site, and body, over time. The discussion pivots around a series of studies that replace linear or causal relationships – in history, drawing and expression – with topological movement. My approach is largely through a speculative case study. In a rereading of the familiar Butades myth, I examine how a shadow tracing can variously be taken as the first mimetic art with its origins in the urge to “capture”, and, antithetically, as the originary expressive folding of matter, site and body. The paper is divided into five sections. The first presents the Butades myth, identifying the representational problem that lies at the roots of its traditional telling. The next three sections outline a series of topologies that facilitate a discussion of the Butades myth from historical, disciplinary, and expressive perspectives. The final section aims to show the relevance of this discussion to a contemporary drawing practice, using my own drawing research as a case study. The field of inquiry is that of representational critique. The fold, an image associated with a topological geometry, replaces the relational or signifying disjuncture of representational structures, and suggests a becoming- expressive of subject and object, form and matter.

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We report the first 3D maps of genetic effects on brain fiber complexity. We analyzed HARDI brain imaging data from 90 young adult twins using an information-theoretic measure, the Jensen-Shannon divergence (JSD), to gauge the regional complexity of the white matter fiber orientation distribution functions (ODF). HARDI data were fluidly registered using Karcher means and ODF square-roots for interpol ation; each subject's JSD map was computed from the spatial coherence of the ODFs in each voxel's neighborhood. We evaluated the genetic influences on generalized fiber anisotropy (GFA) and complexity (JSD) using structural equation models (SEM). At each voxel, genetic and environmental components of data variation were estimated, and their goodness of fit tested by permutation. Color-coded maps revealed that the optimal models varied for different brain regions. Fiber complexity was predominantly under genetic control, and was higher in more highly anisotropic regions. These methods show promise for discovering factors affecting fiber connectivity in the brain.

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Axillary shoots of Nicotiana benthamiana were regenerated from nodal explants in two weeks using MS media supplemented with the cytokinin, kinetin (0.5 mg/L), and the auxin, indole-3-butyric acid (IBA) (0.1 mg/L). Ninety two percent of shoots were 2.1-20 mm tall, a size ideal for root induction. After transfer to hormone-free MS they readily produced roots within seven days, with phenotypically normal, fully developed plants being obtained within four weeks. Leaf chlorosis due to iron deficiency was observed in plants over time, however, this was overcome by doubling the concentration of inorganic iron. This rapid micro-propagation system is particularly useful for the in vitro mass production of N. benthamiana plants for various biotechnological applications.

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In the context of recent education reform, Queensland’s Preparatory Year (Prep) is undergoing a period of significant change. The framing of Prep under a new national curriculum reflects a shift from its play-based roots to a formalised subject-based approach. This shift coincides with suggestions that parents may favour more formalised approaches to teaching and learning in the early years. This paper reports on two studies in which parents were interviewed about their views of play in Prep. Data were analysed thematically, with a focus on themes used by parents to talk about play. While parents broadly valued play, the findings suggest that parent participation greatly influenced their acceptance of play-based learning in the formal learning context of Prep. The findings raise implications for educators in fostering strong parent-teacher partnerships in order to facilitate improved parental understanding and support of play in early childhood programs.