999 resultados para Radical sports
Resumo:
Digital Image
Resumo:
Digital Image
Resumo:
Atomic Layer Deposition (ALD) is a chemical, gas-phase thin film deposition method. It is known for its ability for accurate and precise thickness control, and uniform and conformal film growth. One area where ALD has not yet excelled is film deposition at low temperatures. Also deposition of metals, besides the noble metals, has proven to be quite challenging. To alleviate these limitations, more aggressive reactants are required. One such group of reactants are radicals, which may be formed by dissociating gases. Dissociation is most conveniently done with a plasma source. For example, dissociating molecular oxygen or hydrogen, oxygen or hydrogen radicals are generated. The use of radicals in ALD may surmount some of the above limitations: oxide film deposition at low temperatures may become feasible if oxygen radicals are used as they are highly reactive. Also, as hydrogen radicals are very effective reducing agents, they may be used to deposit metals. In this work, a plasma source was incorporated in an existing ALD reactor for radical generation, and the reactor was used to study five different Radical Enhanced ALD processes. The modifications to the existing reactor and the different possibilities during the modification process are discussed. The studied materials include two metals, copper and silver, and three oxides, aluminium oxide, titanium dioxide and tantalum oxide. The materials were characterized and their properties were compared to other variations of the same process, utilizing the same metal precursor, to understand what kind of effect the non-metal precursor has on the film properties and growth characteristics. Both metals were deposited successfully, and silver for the first time by ALD. The films had low resistivity and grew conformally in the ALD mode, demonstrating that the REALD of metals is true ALD. The oxide films had exceptionally high growth rates, and aluminium oxide grew at room temperature with low cycle times and resulted in good quality films. Both aluminium oxide and titanium dioxide were deposited on natural fibres without damaging the fibre. Tantalum oxide was also deposited successfully, with good electrical properties, but at slightly higher temperature than the other two oxides, due to the evaporation temperature required by the metal precursor. Overall, the ability of REALD to deposit metallic and oxide films with high quality at low temperatures was demonstrated.
Resumo:
In competitive combat sporting environments like boxing, the statistics on a boxer's performance, including the amount and type of punches thrown, provide a valuable source of data and feedback which is routinely used for coaching and performance improvement purposes. This paper presents a robust framework for the automatic classification of a boxer's punches. Overhead depth imagery is employed to alleviate challenges associated with occlusions, and robust body-part tracking is developed for the noisy time-of-flight sensors. Punch recognition is addressed through both a multi-class SVM and Random Forest classifiers. A coarse-to-fine hierarchical SVM classifier is presented based on prior knowledge of boxing punches. This framework has been applied to shadow boxing image sequences taken at the Australian Institute of Sport with 8 elite boxers. Results demonstrate the effectiveness of the proposed approach, with the hierarchical SVM classifier yielding a 96% accuracy, signifying its suitability for analysing athletes punches in boxing bouts.
Resumo:
Arts education research, as an interdisciplinary field, has developed in the shadows of a number of research traditions. However amid all the methodological innovation, I believe there is one particular, distinctive and radical research strategy which arts educators have created to research the practice of arts education: namely arts-based research. For many, and Elliot Eisner from Stanford University was among the first, arts education needed a research approach which could deal with the complex dynamics of arts education in the classroom. What was needed was ‘an approach to the conduct of educational research that was rooted in the arts and that used aesthetically crafted forms to reveal aspects of practice that mattered educationally’ (Eisner 2006: 11). While arts education researchers were crafting the principles and practices of arts-based research, fellow artist/researchers in the creative arts were addressing similar needs and fashioning their own exacting research strategies. This chapter aligns arts-based research with the complementary research practices established in creative arts studios and identifies the shared and truly radical nature of these moves. Finally, and in a contemporary turn many will find surprising, I will discuss how the radical aspects of these methodologies are now being held up as core elements of what is being called the fourth paradigm of scientific research, known as eScience. Could it be that the radical dynamics of arts-based research pre-figured the needs of eScience researchers who are currently struggling to manage the ‘deluge of Big Data’ which is disrupting their well-established scientific methods?
Resumo:
The first glycyl radical in an enzyme was described 20 years ago and since then the family of glycyl radical enzymes (GREs) has expanded to include enzymes catalysing five chemically distinct reactions. The type enzymes of the family, anaerobic ribonucleotide reductase (RNRIII) and pyruvate formate lyase (PFL) had been studied long before it was known that they are GREs. Spectroscopic measurements on the radical and an observation that exposure to oxygen irreversibly inactivates the enzymes by cleavage of the protein proved that the radical is located on a particular glycine residue, close to the C-terminus of the protein. Both anaerobic RNRIII and PFL, are important for many anaerobic and facultative anaerobic bacteria as RNRIII is responsible for the synthesis of DNA precursors and PFL catalyses a key metabolic reaction in glycolysis. The crystal structures of both were solved in 1999 and they revealed that, although the enzymes do not share significant sequence identity, they share a similar structure - the radical site and residues necessary for catalysis are buried inside a ten stranded $\ualpha $/$\ubeta $-barrel. GREs are synthesised in an inactive form and are post-translationally activated by an activating enzyme which uses S-adenosyl methionine and an iron-sulphur cluster to generate the radical. One of the goals of this thesis work was to crystallise the activating enzyme of PFL. This task is challenging as, like GREs, the activating component is inactivated by oxygen. The experiments were therefore carried out in an oxygen free atmosphere. This is the first report of a crystalline GRE activating enzyme. Recently several new GREs have been characterised, all sharing sequence similarity to PFL but not to RNRIII. Also, the genome sequencing projects have identified many PFL-like GREs of unknown function, usually annotated as PFLs. In the present thesis I describe the grouping of these PFL family enzymes based on the sequence similarity and analyse the conservation patterns when compared to the structure of E. coli PFL. Based on this information an activation route is proposed. I also report a crystal structure of one of the PFL-like enzymes with unknown function, PFL2 from Archaeoglobus fulgidus. As A. fulgidus is a hyperthermophilic organism, possible mechanisms stabilising the structure are discussed. The organisation of an active site of PFL2 suggests that the enzyme may be a dehydratase. Keywords: glycyl radical, enzyme, pyruvate formate lyase, x-ray crystallography, bioinformatics
Resumo:
Reaction of the bromoketals 3, 7a-g and 11 with tri-n-butyltin chloride and sodium cyanoborohydride in the presence of a catalytic amount of AIBN furnished the ethers 5, 8a-g and 13 via a tandem sequence comprising of a radical cyclisation reaction and tri-n-butylhalostannane and sodium cyanoborohydride mediated reductive demethoxylation of the resulting cyclic ketals.
Resumo:
The Sport Development Project (SDP) was a comprehensive youth strategy for sport in the Northern Territory aimed at diversion from ‘at-risk’ behaviours, improvement of life choices and outcomes, and strengthening youth service infrastructure through engagement in positive (sport) activities. There were five Remote Service Delivery sites that were involved in the trial of this ‘best practice’ model for delivering sport-focused diversion activities. These include: Gapuwiyak, Wadeye, Yuendumu, Gunbalunya and Nguiu.
Resumo:
The objective of this research project was to consider the social impact of sport and physical activity on the lives of Indigenous Australians and their communities. There has been strong research interest in the links between sport and recreation programs and various health and social outcomes and a well-established body of literature exists on the use of sport to address social issues in mainstream society (A Thomson, Darcy and Pearce 2010). The consensus is that physical activity is an important contributor to health for all people (Nelson, Abbott and Macdonald 2010). While there is strong research interest, what remains unclear is the value and impact of sport and physical activity on Indigenous communities (Cairnduff 2001). Nelson (2009) drawing on the work of Jonas and Langton (1994) indicates that an ‘Aboriginal person is a descendant of an Indigenous inhabitant of Australia, identifi es as an Aboriginal, and is recognised as Aboriginal by members of the community in which he or she lives’ (p. 97). Even this defi nition has the potential to be politically charged. At a general level, the collective terms ‘Indigenous’ (capitalised) and ‘Aboriginal and Torres Strait Islander’ people (title capitalised) appear to be broadly acceptable terms. Indigenous groups cannot be considered to be homogenous as there is much diversity between and within groups (Nelson et al. 2010; Parker et al. 2006). It is therefore important this report is not viewed as taking an essentialist view of who Indigenous people are and how they develop. Rather, this paper attempts to describe and discuss the experiences of some individuals and their communities in site-specifi c surfi ng programs.
Resumo:
The aim of this paper is to provide a Bayesian formulation of the so-called magnitude-based inference approach to quantifying and interpreting effects, and in a case study example provide accurate probabilistic statements that correspond to the intended magnitude-based inferences. The model is described in the context of a published small-scale athlete study which employed a magnitude-based inference approach to compare the effect of two altitude training regimens (live high-train low (LHTL), and intermittent hypoxic exposure (IHE)) on running performance and blood measurements of elite triathletes. The posterior distributions, and corresponding point and interval estimates, for the parameters and associated effects and comparisons of interest, were estimated using Markov chain Monte Carlo simulations. The Bayesian analysis was shown to provide more direct probabilistic comparisons of treatments and able to identify small effects of interest. The approach avoided asymptotic assumptions and overcame issues such as multiple testing. Bayesian analysis of unscaled effects showed a probability of 0.96 that LHTL yields a substantially greater increase in hemoglobin mass than IHE, a 0.93 probability of a substantially greater improvement in running economy and a greater than 0.96 probability that both IHE and LHTL yield a substantially greater improvement in maximum blood lactate concentration compared to a Placebo. The conclusions are consistent with those obtained using a ‘magnitude-based inference’ approach that has been promoted in the field. The paper demonstrates that a fully Bayesian analysis is a simple and effective way of analysing small effects, providing a rich set of results that are straightforward to interpret in terms of probabilistic statements.
Resumo:
Formation of oxygen radicals during reduction of H2O2 or diperoxovanadate with vanadyl sulfate or ferrous sulfate was indicated by the 1:2:2:1 electron spin resonance (ESR) signals of the DMPO adduct typical of standard radical dotOH radical. Signals derived from diperoxovanadate remained unchanged in the presence of ethanol in contrast to those from H2O2. This gave the clue that they represent a different radical, possibly radical dotOV(O2)2+, formed on breaking a peroxo-bridge of diperoxovanadate complex. The above reaction mixtures evolved dioxygen or, when NADH was present, oxidized it rapidly which was accompanied by consumption of dioxygen. Operation of a cycle of peroxovanadates including this new radical is suggested to explain these redox activities both with vanadyl and ferrous sulfates. It can be triggered by ferrous ions released from cellular stores in the presence of catalytic amounts of peroxovanadates.