977 resultados para genetic mapping


Relevância:

20.00% 20.00%

Publicador:

Resumo:

The genetic structure of rice tungro bacilliform virus (RTBV) populations within and between growing sites was analyzed in a collection of natural field isolates from different rice varieties grown in eight tungro-endemic sites of the Philippines. Total DNA extracts from 345 isolates were digested with EcoRV restriction enzyme and hybridized with a full-length probe of RTBV, a procedure shown in preliminary experiments capable of revealing high levels of polymorphism in RTBV field isolates. In the total population, 17 distinct EcoRV-based genome profiles (genotypes) were identified and used as indicators for virus diversity. Distinct sets of genotypes occurred in Isabela and North Cotabato provinces suggesting a geographic isolation of virus populations. However, among the sites in each province, there were few significant differences in the genotype compositions of virus populations. The number of genotypes detected at a site varied from two to nine with a few genotypes dominating. In general the isolates at a site persisted from season to season indicating a genetic stability for the local virus population. Over the sampling time, IRRI rice varieties, which have green leafhopper resistance genes, supported similar virus populations to those supported by other varieties, indicating that the variety of the host exerted no apparent selection pressures. Insect transmission experiments on selected RTBV field isolates showed that dramatic shifts in genotype and phenotype distributions can occur in response to host /environmental shifts.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We have recently demonstrated the geographic isolation of rice tungro bacilliform virus (RTBV) populations in the tungro-endemic provinces of Isabela and North Cotabato, Philippines. In this study, we examined the genetic structure of the virus populations at the tungro-outbreak sites of Lanao del Norte, a province adjacent to North Cotabato. We also analyzed the virus populations at the tungro-endemic sites of Subang, Indonesia, and Dien Khanh, Vietnam. Total DNA extracts from 274 isolates were digested with EcoRV restriction enzyme and hybridized with a full-length probe of RTBV. In the total population, 22 EcoRV-restricted genome profiles (genotypes) were identified. Although overlapping genotypes could be observed, the outbreak sites of Lanao del Norte had a genotype combination distinct from that of Subang or Dien Khanh but a genotype combination similar to that identified earlier from North Cotabato, the adjacent endemic province. Sequence analysis of the intergenic region and part of the ORF1 RTBV genome from randomly selected genotypes confirms the geographic clustering of RTBV genotypes and, combined with restriction analysis, the results suggest a fragmented spatial distribution of RTBV local populations in the three countries. Because RTBV depends on rice tungro spherical virus (RTSV) for transmission, the population dynamics of both tungro viruses were then examined at the endemic and outbreak sites within the Philippines. The RTBV genotypes and the coat protein RTSV genotypes were used as indicators for virus diversity. A shift in population structure of both viruses was observed at the outbreak sites with a reduced RTBV but increased RTSV gene diversity

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In cloud computing resource allocation and scheduling of multiple composite web services is an important challenge. This is especially so in a hybrid cloud where there may be some free resources available from private clouds but some fee-paying resources from public clouds. Meeting this challenge involves two classical computational problems. One is assigning resources to each of the tasks in the composite web service. The other is scheduling the allocated resources when each resource may be used by more than one task and may be needed at different points of time. In addition, we must consider Quality-of-Service issues, such as execution time and running costs. Existing approaches to resource allocation and scheduling in public clouds and grid computing are not applicable to this new problem. This paper presents a random-key genetic algorithm that solves new resource allocation and scheduling problem. Experimental results demonstrate the effectiveness and scalability of the algorithm.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Skipjack (SJT) (Katsuwonus pelamis) is a medium sized, pelagic, highly dispersive tuna species that occurs widely across tropical and subtropical waters. SJT constitute the largest tuna fishery in the Indian Ocean, and are currently managed as a single stock. Patterns of genetic variation in a mtDNA gene and 6 microsatellite loci were examined to test for stock structure in the northwestern Indian Ocean. 324 individuals were sampled from five major fishing grounds around Sri Lanka, and single sites in the Maldive Islands and the Laccadive Islands. Phylogenetic reconstruction of mtDNA revealed two coexisting divergent clades in the region. AMOVA (Analysis of Molecular Variance) of mtDNA data revealed significant genetic differentiation among sites (ΦST = 0.2029, P < 0.0001), also supported by SAMOVA results. AMOVA of microsatellite data also showed significant differentiation among most sampled sites (FST = 0.0256, P<0.001) consistent with the mtDNA pattern. STRUCTURE analysis of the microsatellite data revealed two differentiated stocks. While the both two marker types examined identified two genetic groups, microsatellite analysis indicates that the sampled SJT are likely to represent individuals sourced from discrete breeding grounds that are mixed in feeding grounds in Sri Lankan waters.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Maps are used to represent three-dimensional space and are integral to a range of everyday experiences. They are increasingly used in mathematics, being prominent both in school curricula and as a form of assessing students understanding of mathematics ideas. In order to successfully interpret maps, students need to be able to understand that maps: represent space, have their own perspective and scale, and their own set of symbols and texts. Despite the fact that maps have an increased prevalence in society and school, there is evidence to suggest that students have difficulty interpreting maps. This study investigated 43 primary-aged students’ (aged 9-12 years) verbal and gestural behaviours as they engaged with and solved map tasks. Within a multiliteracies framework that focuses on spatial, visual, linguistic, and gestural elements, the study investigated how students interpret map tasks. Specifically, the study sought to understand students’ skills and approaches used to solving map tasks and the gestural behaviours they utilised as they engaged with map tasks. The investigation was undertaken using the Knowledge Discovery in Data (KDD) design. The design of this study capitalised on existing research data to carry out a more detailed analysis of students’ interpretation of map tasks. Video data from an existing data set was reorganised according to two distinct episodes—Task Solution and Task Explanation—and analysed within the multiliteracies framework. Content Analysis was used with these data and through anticipatory data reduction techniques, patterns of behaviour were identified in relation to each specific map task by looking at task solution, task correctness and gesture use. The findings of this study revealed that students had a relatively sound understanding of general mapping knowledge such as identifying landmarks, using keys, compass points and coordinates. However, their understanding of mathematical concepts pertinent to map tasks including location, direction, and movement were less developed. Successful students were able to interpret the map tasks and apply relevant mathematical understanding to navigate the spatial demands of the map tasks while the unsuccessful students were only able to interpret and understand basic map conventions. In terms of their gesture use, the more difficult the task, the more likely students were to exhibit gestural behaviours to solve the task. The most common form of gestural behaviour was deictic, that is a pointing gesture. Deictic gestures not only aided the students capacity to explain how they solved the map tasks but they were also a tool which assisted them to navigate and monitor their spatial movements when solving the tasks. There were a number of implications for theory, learning and teaching, and test and curriculum design arising from the study. From a theoretical perspective, the findings of the study suggest that gesturing is an important element of multimodal engagement in mapping tasks. In terms of teaching and learning, implications include the need for students to utilise gesturing techniques when first faced with new or novel map tasks. As students become more proficient in solving such tasks, they should be encouraged to move beyond a reliance on such gesture use in order to progress to more sophisticated understandings of map tasks. Additionally, teachers need to provide students with opportunities to interpret and attend to multiple modes of information when interpreting map tasks.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This Preliminary Report has been prepared by researchers at The Australian Expert Group in Industry Studies (AEGIS) for the Commonwealth Department of Industry, Science and Resources. It is intended to provide a preliminary 'product system map' of the building and construction industries which defines the system, identifies the major segments, describes key industry players and institutions and provides the basis for exploring relationships, innovation and information flows within the industries. This Preliminary Report is the first of a series of five which will explore the building and construction product system in some depth. This first report does not present original research, although it does include some new interview data and analysis of a variety of written sources. This report is rather a reformulation of existing statistical and analytical material from a product system-based perspective. It is intended to provide the basis for subsequent studies by putting what is already known into an alternative framework and allowing us to see it through a new lens.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Genetic variation is the resource animal breeders exploit in stock improvement programs. Both the process of selection and husbandry practices employed in aquaculture will erode genetic variation levels overtime, hence the critical resource can be lost and this may compromise future genetic gains in breeding programs. The amount of genetic variation in five lines of Sydney Rock Oyster (SRO) that had been selected for QX (Queensland unknown) disease resistance were examined and compared with that in a wild reference population using seven specific SRO microsatellite loci. The five selected lines had significantly lower levels of genetic diversity than did the wild reference population with allelic diversity declining approximately 80%, but impacts on heterozygosity per locus were less severe. Significant deficiencies in heterozygotes were detected at six of the seven loci in both mass selected lines and the wild reference population. Against this trend however, a significant excess of heterozygotes was recorded at three loci Sgo9, Sgo14 and Sgo21 in three QX disease resistant lines (#2, #5 and #13). All populations were significantly genetic differentiated from each other based on pairwise FST values. A neighbour joining tree based on DA genetic distances showed a clear separation between all culture and wild populations. Results of this study show clearly, that the impacts of the stock improvement program for SRO has significantly eroded natural levels of genetic variation in the culture lines. This could compromise long-term genetic gains and affect sustainability of the SRO breeding program over the long-term.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This research project looks to engage audiences in a variety of experiential ways by reexamining and manipulating the traditional presentation paradigm for viewing Western contemporary dance. It considers how the audience may be situated in the creation and presentation of contemporary dance generally, and specifically in the work The Voyeur, which researched these issues in action. By situating the body of the audience member as a site of understanding and meaning making, this practice-based research considers the audience within the artists’ creative process from the inception of a creative work, rather than after the work has been created. The research questions how a ‘lived experience’ of contemporary dance could be deepened for the audience. It presents a series of ‘tools’ to create alternative frameworks of presentation that challenge the dominant modes of creation, presentation and meaning making in contemporary dance. The five tools established and applied in this research are: site, liminality, agency, proximity and performer authenticity. These tools are framed as a series of calibrated scales that allow choreographers to map decisions made in the studio in relation to potential audience engagement. These scales have the ability to house multiple presentation formats from the traditional to the avant garde and open up possibilities for broad analysis of a wide range of artistic dance works.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The aim of this thesis has been to map the ethical journey of experienced nurses now practising in rural and remote hospitals in central and south-west Queensland and in domiciliary services in Brisbane. One group of the experienced nurses in the study were Directors of Nursing in rural and remote hospitals. These nurses were “hands on”, “multi-skilled “ nurses who also had the task of managing the hospital. Also there were two Directors of Nursing from domiciliary services in Brisbane. A grounded theory method was used. The nurses were interviewed and the data retrieved from the interviews was coded, categorised and from these categories a conceptual framework was generated. The literature which dealt with the subject of ethical decision making and nurses also became part of the data. The study revealed that all these nurses experienced moral distress as they made ethical decisions. The decision making categories revealed in the data were: the area of financial management; issues as end of life approaches; allowing to die with dignity; emergency decisions; experience of unexpected death; the dilemma of providing care in very difficult circumstances. These categories were divided into two chapters: the category related to administrative and financial constraints and categories dealing with ethical issues in clinical settings. A further chapter discussed the overarching category of coping with moral distress. These experienced nurses suffered moral distress as they made ethical decisions, confirming many instances of moral distress in ethical decision making documented in the literature to date. Significantly, the nurses in their interviews never mentioned the ethical principles used in bioethics as an influence in their decision making. Only one referred to lectures on ethics as being an influence in her thinking. As they described their ethical problems and how they worked through them, they drew on their own previous experience rather than any knowledge of ethics gained from nursing education. They were concerned for their patients, they spoke from a caring responsibility towards their patients, but they were also concerned for justice for their patients. This study demonstrates that these nurses operated from the ethic of care, tempered with the ethic of responsibility as well as a concern for justice for their patients. Reflection on professional experience, rather than formal ethics education and training, was the primary influence on their ethical decision making.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Australian National Cinema and Australian Television Culture. These two books, magisterial accounts of Australian media cultures, are very different. The first analyses (according to its cover blurb) 'the distinct and diverse nature of Australian cinema'; the second offers 'a picture of Australian television'. The books share an author.2 Despite this, their objects of study are constituted very differently. The first is replete with examples of particular films, analyses of their representational strategies, and links to the social context of production. The second addresses almost no programs and those that are mentioned appear only in passing. There is no analysis of any particular television text. The difference between these books cannot be explained in terms of authorial fickleness: rather, it represents the different ways in which television and film have been constructed as objects of study. While film has a recognised canon and a tradition of close textual analysis, in the study of television the programs themselves have tended to vanish - as they do in Australian Television Culture. Most academic work on Australian television is not interested in its programs. Writers have tended to find other aspects more rewarding: industries, institutions, ownership, legislation, technology and production.3 Australian Television Culture is part of this tradition; and an example of how such work, done well, can be a useful contribution to understanding the medium.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

1. A diverse array of patterns has been reported regarding the spatial extent of population genetic structure and effective dispersal in freshwater macroinvertebrates. In river systems, the movements of many taxa can be restricted to varying degrees by the natural stream channel hierarchy. 2. In this study, we sampled populations of the non-biting freshwater midge Echinocladius martini in the Paluma bioregion of tropical northeast Queensland to investigate fine scale patterns of within- and among-stream dispersal and gene flow within a purported historical refuge. We amplified a 639 bp fragment of mitochondrial COI and analysed genetic structure using pairwise ΦST, hierarchical AMOVA, Mantel tests and a parsimony network. Genetic variation was partitioned among stream sections using Streamtree to investigate the effect of potential instream dispersal barriers. 3. The data revealed strong natal site fidelity and significant differentiation among neighbouring, geographically proximate streams. We found evidence for only episodic adult flight among sites on separate stream reaches. Overall, however, our data suggested that both larval and adult dispersal was largely limited to within a stream channel. 4. This may arise from a combination of the high density of riparian vegetation physically restricting dispersal and from the joint effects of habitat stability and large population sizes. Together these may mitigate the requirement for movement among streams to avoid inbreeding and local extinction due to habitat change and may thus enable persistence of upstream populations in the absence of regular compensatory upstream flight. Taken together, these data suggest that dispersal of E. martini is highly restricted, to the scale of only a few kilometres, and hence occurs predominantly within the natal stream.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The indecision surrounding the definition of Technology extends to the classroom as not knowing what a subject “is” affects how it is taught. Similarly, its relative newness – and consequent lack of habitus in school settings - means that it is still struggling to find its own place in the curriculum as well as resolve its relationship with more established subject domains, particularly Science and Mathematics. The guidance from syllabus documents points to open-ended student-directed projects where extant studies indicate a more common experience of teacher –directed activities and an emphasis on product over process. There are issues too for researchers in documenting classroom observations and in analysing teacher practice in new learning environments. This paper presents a framework for defining and mapping classroom practice and for attempting to describe the social practice in the Technology classroom. The framework is a bricolage which draws on contemporary research. More formally, the development of the framework is consonant with the aim of design-based research to develop a flexible, adaptive and generalisable theory to better understanding a teaching domain where promise is not seen to match current reality. The framework may also inform emergent approaches to STEM (Science, Technology, Education and Mathematics) in education.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Background Chlamydia pneumoniae is a widespread pathogen causing upper and lower respiratory tract infections in addition to a range of other diseases in humans and animals. Previous whole genome analyses have focused on four essentially clonal (> 99% identity) C. pneumoniae human genomes (AR39, CWL029, J138 and TW183), providing relatively little insight into strain diversity and evolution of this species. Results We performed individual gene-by-gene comparisons of the recently sequenced C. pneumoniae koala genome and four C. pneumoniae human genomes to identify species-specific genes, and more importantly, to gain an insight into the genetic diversity and evolution of the species. We selected genes dispersed throughout the chromosome, representing genes that were specific to C. pneumoniae, genes with a demonstrated role in chlamydial biology and/or pathogenicity (n = 49), genes encoding nucleotide salvage or amino acid biosynthesis proteins (n = 6), and extrachromosomal elements (9 plasmid and 2 bacteriophage genes). Conclusions We have identified strain-specific differences and targets for detection of C. pneumoniae isolates from both human and animal origin. Such characterisation is necessary for an improved understanding of disease transmission and intervention.