75 resultados para Tree-rings


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In this habitat mapping study, multi-beam acoustic data are integrated with extensive, precisely geo-referenced video validation data in a GIS environment to classify benthic substrates and biota at a 33km2 site in the near shore waters of Victoria, Australia. Using an automated decision-tree classification method, 5 representative biotic groups were identified in the Cape Nelson survey area using a combination of multi-beam bathymetry, backscatter and derivative products. Rigorous error assessment of derived, classified maps produced high overall accuracies (>85%) for all mapping products. In addition, a discrete multivariate analysis technique (kappa analysis) was used to assess classification accuracy. High-resolution (2.5m cell-size) representation of sea floor morphology and textural characteristics provided by multi-beam bathymetry and backscatter datasets, allowed the interpretation of benthic substrates of the Cape Nelson site and the communities of sessile organisms that populate them. Non-parametric multivariate statistical analysis (ANOSIM) revealed a significant difference in biotic composition between depth strata, and between substrate types. Incorporated with other descriptive measures, these results indicate that depth and substrate are important factors in the distributional ecology of the biotic communities at the Cape Nelson study site. BIOENV analysis indicates that derivatives of both multi-beam datasets (bathymetry and backscatter) are correlated with distribution and density of biotic communities. Results from this study provide new tools for research and management of the coastal zone.

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As early as Level 3 in VELS [Victorian Essential Learning Standards], the topics of Venn diagrams, Carroll Diagrams (which are identical to Karnaugh Maps) and Trees Sorts, are introduced as powerful visual organisers of categories. A selection of challenging tasks for these tools at various levels, including Level 9, are provided.

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Allergy to peanut and tree nuts is characterised by a high frequency of life-threatening anaphylactic reactions and typically lifelong persistence. Although peanut is the most common cause of nut allergy, peanut allergic patients are frequently also sensitive to tree nuts. It is not known if this is due to cross-reactivity between peanut and tree nut allergens. In this study, the major peanut allergen Ara h 2 was cloned from peanut cDNA, expressed in E. coli cells as a His-tag fusion protein and purified using a Ni-NTA column. Immunoblotting, ELISA and basophil activation indicated by CD63 expression all confirmed the IgE reactivity and biological activity of rAra h 2. To determine whether or not this allergen plays a role in IgE cross-reactivity between peanut and tree nuts, inhibition ELISA was performed. Pre-incubation of serum from peanut allergic patients with increasing concentrations of almond or Brazil nut extract inhibited IgE binding to rAra h 2. Purified rAra h 2-specific serum IgE antibodies also bound to proteins present in almond and Brazil nut extracts by immunoblotting. This indicates that the major peanut allergen, Ara h 2, shares common IgE-binding epitopes with almond and Brazil nut allergens, which may contribute to the high incidence of tree nut sensitisation in peanut allergic individuals.

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Here we document the investigation of the first Australian Aboriginal mortuary tree found since the early 20th century and the first studied by archaeologists and Aboriginal traditional owners. In 2001, a landowner discovered Aboriginal skeletal remains inside a fallen, dead tree while evaluating the tree’s potential as firewood, leading to the investigation of the site. The tree was located near Moyston, in southwestern Victoria, in traditional Djab Wurrung country and held the partial skeletons of three Aboriginal individuals—two adults and a child. Clay pipe-stem wear on several teeth belonging to the two adults indicates that these remains were broadly contemporaneous secondary placements from the early post-contact period (ca. A.D. 1835–1845). Along with five additional mortuary trees within 30 km of the Moyston tree, this practice constitutes a previously unknown traditional mortuary pattern and contributes to our understanding of the complex mortuary behavior of the Aboriginal people of southwestern Victoria.

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This thesis represents a part of a program of study that is reaching a closure. The broadest brush that could be applied to my work is that it concerns Physical Education Teacher Education (PETE), that it focuses on aspects of professional socialisation, and that it involves various case studies utilising naturalistic inquiry. Whilst it would be impossible and naive to believe that the reading of these texts will produce the meanings that I encourage, or have internalised, nevertheless the order of reading is at least something that I can argue for. Read in the order I suggest throughout the thesis I am hopeful that my subjectivities, and the learning and understandings I have reached may become clear. The purpose of this two part thesis is an exploration of the interplay or dialectic that exists between PETE students, academic staff and the subject matter within PETE. I have had to come to understand the limitations and advantages of insider research as the work has been completed at my University in the School of Human Movement and Sports Science where I have worked for twenty years. This thesis examines the extent to which studentship and oppositional behaviour underlies the dialectic that exists between the students and the various discourses within the program. I have written the study in two very different formats, one, a collection of stories about PETE and the other, an interpretative case study conducted during 1993 and 1994. Within the case study, studentship and oppositional behaviour were viewed as a measure of the extent to which students react and push against the forces of socialisation within their PETE program that is seen to represent dominant discourses, The following broad research questions were considered to enable the above analysis. 1. What is the nature of studentship and oppositional behaviour in a high status subject within PETE compared to a subject that is seen by students to be of little relevance and of low status? 2. How are studentship and oppositional behaviour related to students subjective warrants? 3. How are the studentship and oppositional behaviours exhibited by students related to the pedagogy and discourses reflected in the knowledge, beliefs and practices within the two sites. The starting point for this research was a study conducted as a totally separate research task (Swan, 1992) that investigated the hierarchies of subject knowledge within a PETE site and investigated the influence of such hierarchies upon student intention. A great deal of meta analysis exists about the manner in which a technocratic rationality pervades PETE but very little case study material of what this means to students and academic staff within such institutions is available. The stories in Between The Rings And Under The Gym Mat, which is the second part of this thesis, represent ‘the data’ differently from the case study, but they speak their own truth. At times the nature of the story is indistinguishable from the reality of the case study. Wexler (1992) undertook an ethnographic study about identity formation in three very different high schools, and published the findings in a book entitled Becoming Somebody. His introductory words about the nature of the social story he tells, are significant to this study and story. Social history is recounted by creative intervention that can only be made from culturally accessible materials. Ethnography is neither an objective realist, nor subjective imaginist account. Rather, it is an historical artefact that is mediated by elaborated distancing of culturally embedded and internally contradictory (but seemingly independent and coherent) concepts that take on a life of their own as theory. So, this is not ‘news from nowhere,’ but a theoretically structured story where both the story and its structure are part of my times. (p.6) The case study before you is organised with an analysis of studentship and oppositional behaviour detailed in chapter one. The following chapter conceptualises studentship and oppositional behaviour in relation to particular themes of professional socialisation, resistance to oppression and youth culture. Chapter three locates the case study to the major paradigmatic debates about the value and nature of the subject matter content within PETE, Chapter four outlines the case site, the research process and the research dilemma’s confronted in this study. The remaining three chapters are the case record as I can best understand it. In Between the Rings and under the Gym Mat (part B) the story most directly concerned with studentship and oppositional behaviour, is called Tale of Two Classes’. It takes on a very different reality to the case study (part A) and much can be said about the reality of lived experience which can be portrayed in narrative form as opposed to a clinical case study. Many of the other stories pose similar images that are contradictory and never quite complete. I have written a separate methodological section for the narrative stories. It is my intention that the case study and the series of stories should be viewed as essentially complementary, but also a discrete representation of a part of PETE. As part of the Ed D program I have undertaken four discrete research tasks as the starting point for this research I have referred to the first one (Hierarchies of Subject knowledge within PETE). I also undertook an action research project about ‘Teaching Poorly by Choice.’ A further piece of research was a somewhat reflective effort to draw together what this has all meant to me from a subjective and reflexive perspective. Such efforts are often seen as being self indulgent, as subjectivity in the form of lived experience sits uneasily in academia. A final paper involved an evaluation of Between the Rings and Under the Gym Mat from a pedagogical perspective by PETE professionals around the world. And that's the way things turned out.

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Eleven novel polymorphic microsatellite loci developed from a microsatellite enriched genomic library, are presented for the Australian tree frog <i>Litoria peroniii>. We screened 29 individuals from a single population and detected high levels of polymorphism for all 11 loci with the number of alleles/locus ranging from 9 to 24. Values of expected and observed heterozygosities ranged from 0.789–0.955 and 0.207–1.00, respectively. These microsatellite markers should prove useful in determining levels of genetic diversity, measuring gene flow and migration, assigning individuals to their most likely population of origin, and in the assignment of paternity.

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Sperm number is often a good predictor of success in sperm competition; however, it has become increasingly clear that, for some species, variation in probability of paternity cannot be explained by sperm number alone. Intraspecific variation in ejaculate characteristics, such as the number of viable sperm and sperm longevity, may play an equally important role in determining fertilization success. Here, we assess variation among ejaculates in three factors that may contribute to fertilization success (number of sperm per ejaculate, viability, and longevity), in a population of Peron’s tree frog (Litoria peronii). We detected large variation among males in the number of sperm per ejaculate and the proportion of viable sperm within ejaculates, which could not be explained by variation in either male size or body condition. However, the proportion of viable sperm released by males increased over the season. Finally, we assessed sperm longevity (proportion viable sperm determined using a dual-fluorochrome vital dye) at two different temperatures. At 23°C, on average, 75% of sperm remained viable after 2 h, but there were significant differences amongst males with the percentage of viable sperm ranging from 43% to 95%. For sperm incubated at 4°C, ejaculates varied fivefold in sperm longevity with some males having 50% viable sperm after 5 days. Our data suggest that ejaculate characteristics (sperm number, viability, and longevity) vary widely in Peron’s tree frog and may therefore play an important role in determining siring success both in the presence and absence of sperm competition. We discuss the results in relation to selection on ejaculate traits via natural and sexual selection in this and other amphibians.

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Background
A large number of studies in postcopulatory sexual selection use paternity success as a proxy for fertilization success. However, selective mortality during embryonic development can lead to skews in paternity in situations of polyandry and sperm competition. Thus, when assessment of paternity fails to incorporate mortality skews during early ontogeny, this may interfere with correct interpretation of results and subsequent evolutionary inference. In a previous series of in vitro sperm competition experiments with amphibians (Litoria peronii), we showed skewed paternity patterns towards males more genetically similar to the female.

Methodology/Principal Findings
Here we use in vitro fertilizations and sperm competition trials to test if this pattern of paternity of fully developed tadpoles reflects patterns of paternity at fertilization and if paternity skews changes during embryonic development. We show that there is no selective mortality through ontogeny and that patterns of paternity of hatched tadpoles reflects success of competing males in sperm competition at fertilization.

Conclusions/Significance
While this study shows that previous inferences of fertilization success from paternity data are valid for this species, rigorous testing of these assumptions is required to ensure that differential embryonic mortality does not confound estimations of true fertilization success.

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Hybridization between closely related species often leads to reduced viability or fertility of offspring. Complete failure of hybrid offspring (post-zygotic hybrid incompatibilities) may have an important role in maintaining the integrity of reproductive barriers between closely related species. We show elsewhere that in Peron's tree frog, Litoria peronii, males more closely related to a female sire more offspring in sperm competition with a less related rival male. Observations of rare 'phenotypic intermediate' males between L. peronii and the closely related L. tyleri made us suggest that these relatedness effects on siring success may be because of selection arising from risks of costly hybridization between the two species. Here, we test this hypothesis in an extensive sperm competition experiment, which shows that there is no effect of species identity on probability of fertilization in sperm competition trials controlling for sperm concentration and sperm viability. Instead, there was a close agreement between a male's siring success in isolation with a female and his siring success with the same female in competition with a rival male regardless of species identity. Offspring viability and survival, however, were strongly influenced by species identity. Over a 14-day period, hybrid offspring suffered increasing mortality and developed more malformations and an obvious inability to swim and right themselves, leading to compromised probability of survival. Thus, hybridization in these sympatric tree frogs does not compromise fertilization but has a strong impact on offspring viability and opportunity for reinforcement selection on mate choice for conspecific partners.

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There is increasing theoretical and empirical evidence that genetic compatibility among partners is an important determinant of fertilization success and offspring viability. In amphibians, females often actively choose partners from among a variety of males and polyandry is common. Genetic compatibility among partners may therefore be an important determinant of fertilization success and offspring viability in some amphibians. Amphibians also show some of the highest levels of genetic differentiation among neighbouring populations known in vertebrates, and as such, populations may have evolved different co-adapted gene complexes. This means that offspring from among-population crosses may have reduced fitness. It is therefore essential to understand to what extent crossings between and within populations may interfere with successful fertilization and offspring viability. Here, we test whether crossing individuals within and between two different populations of the Australian Peron's tree frog (Litoria peronii) using artificial fertilizations affect fertilization success and offspring viability. Fertilization success per se is strongly influenced by male identity, which is likely to depend at least to some extent on the experimental procedure (e.g. resulting in variation in sperm number per ejaculate), whereas there was no fertilization effect of female identity. More importantly, male and female identity, independently of each other, explained significant variation in offspring viability, whereas no such effect could be linked to population of origin. Thus, our experiments suggest that crossing populations may not always be the most significant factor affecting fertilization success or offspring viability, but may be more influenced by the genetic quality or the genetic compatibility of partners.

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This considers the challenging task of cancer prediction based on microarray data for the medical community. The research was conducted on mostly common cancers (breast, colon, long, prostate and leukemia) microarray data analysis, and suggests the use of modern machine learning techniques to predict cancer.

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Effective multiple clustering systems, or clusterers, have important applications in information security. The aim of the present article is to introduce a new method of designing multiple clusterers based on theMunn rings and describe a class of optimal clusterers which can be obtained in this construction.