2,562 research outputs found
The effect of complex training on horizontal power production in rugby union players : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science at Massey University
The use of strength and power training regimes is common place among elite and recreational athletes. However, the application of such methods as direct determinants of improvement in sporting performance is a controversial and much debated topic because the degree of transfer from the training exercise to the sporting application is unknown. In recent years combining strength and sport specific training methods into one training session (complex training) has been promoted as a method to enhance training transfer. The purpose of this project was to examine the effect of complex training on horizontal power production in rugby players. 9 participants completed two four week phases of training (complex and standard) in a randomized order. Participant performance in 5RM squat, horizontal force and horizontal power was tested prior to and at the end of each training phase. A number of significant improvements were observed following complex training: maximum slope of the horizontal force curve increased by 12.29 Ā±33.59%, maximum power increased by 15.13 Ā±7.49%, width of the power curve increased by 28.30 Ā±18.16%, and maximum velocity during the horizontal power test improved by 20.63 Ā±14.21%. The improvements were significantly different from the respective standard training measures (p ā¤.05). It is concluded that power gains were a product of an enhanced ability to produce force at higher velocities. No significant weight gain or significant improvement in 5RM force production was associated with the improvement in maximum power. Therefore it is inferred that neural mechanisms accounted for the difference following complex training. The results presented here suggest that complex training not only improves horizontal power production but also transfers performance improvements to an untrained task by improving the rate of force development in the horizontal force condition. It appears that the complex training regime has in some way created a persistent change in the control mechanisms regulating the performance of both the horizontal strength and power conditions
Negotiating the Spaces: Relational Pedagogy and Power in Drama Teaching
While there is a growing body of literature on relational pedagogy as a concept, less attention is given to the details of just how relational pedagogy manifests in classroom practice. Similarly, while issues of power, democracy and co-constructed learning feature in contemporary research, the details of how power relationships can be effectively altered between teachers and children warrants closer scrutiny. This paper explores how pedagogy is enhanced when spaces are negotiated between teachers and children in the real and fictional worlds of drama. The findings emerge from a two year collaborative research project between generalist elementary teachers and university researchers. Salient issues of trust, power sharing, and metaxis, which are part of relational pedagogy in the drama classroom, are explored. In particular, the paper discusses how traditional power and knowledge positions are 'disrupted' through the drama strategy of 'teacher-in-role' - a strategy with both political significance and pedagogical force
Paradox and promise in joint school/university arts research
Collaborative university and school research projects are inevitably labour intensive endeavours that require the careful negotiation of trust and the joint development of critique of current practice. While this raises tension it also builds generative communities of inquiry that can enhance both theory and practice.
This paper reports on an Arts project undertaken in primary classrooms between university staff and generalist teacher co-researchers focusing on childrenās idea development in dance, drama, music and art. This two year project is briefly outlined and some issues that arise in school research are explored. Project collaborators need to exercise caution in their examination of practice and strive to resist premature closure. All parties need to hold the tension of apparent contradictions, being both interested (in effective Arts pedagogy) and disinterested (in order to heighten perception) so that they might āsurprise themselves in a landscape of practice with which many are very familiar indeedā (McWilliam 2004:14). These issues and paradoxes in collaborative research are considered alongside some particular processes that build school and university partnerships
Exploring children's development of ideas in music and dance
Eisner maintains that the Arts education community needs āempirically grounded examples of artistic thinking related to the nature of the tasks students engage in, the material with which they work, the contextās norms and the cues the teacher provides to advance their studentsā thinkingā (2000:217). This paper reflects on preliminary results of a collaborative research project between teachers and university researchers that is investigating how children develop and refine arts-making ideas and related skills in Dance and Music in a small sample of schools in New Zealand. Factors such as the place of repetition in the development of ideas, the relevance of offers, the place of verbal and non-verbal communication in arts idea generation, and group work as an accepted ritual of practice, are explored and discussed
X-ray and neutron topography observations of domains aim dislocations
A brief introduction to the theory of magnetism and magnetic domains is given which is followed by a review of X-ray topography techniques and an outline of the theory and contrast mechanisms necessary for the interpretation of the topographs. Results are presented on the perfection of flux grown rare-earth germanate crystals which clearly indicate the usefulness, to the crystal grower, of synchrotron X-ray topography for rapid routine assessment of a large number of crystals. The techniques of neutron topography are described and some of the more important results obtained are reviewed. Results obtained with neutron topography on the possible correlation between surface vicinal features and dislocations in holmium galium garnet are presented. These results, although not conclusive, provide further evidence of a probable correlation. Previous work reported on the antiferromagnetic KCoF(_3) is described with particular reference to the limited number of domain observations. Previous work on the motion of antiferromagnetic domain walls under an applied magnetic field has been extended by considering the case of the motion of these walls under an applied stress using both synchrotron X-ray topography and rocking curve measurements. The critical stress achieved was in reasonable agreement with that predicted from the magnetic field data. These results also confirm that data obtained in torque magnetometry and linear dichroism experiments may be explained by the motion of antiferromagnetic domain walls under stress. Work on the magnetic properties of terbium is reviewed, particularly work relating to measurements of magnetostriction. An X-ray technique for measuring the magnetostriction of high magnetostriction materials without resorting to absolute lattice parameters is described and the results obtained on using this technique to measure the magnetostriction of terbium are presented. These results are fitted to a two-ion interaction model. Work on the highly magnetostrictive Tb(_.27)Dy(_.73)FE(2) is described and results are presented on the observation of magnetic domains in this material in an applied magnetic field. Calculations of the domain wall energies and widths are presented which enabled the domain structure to be interpreted
An investigation, using an in-vitro alginate biofilm model, into locally delivered antibiotic combinations to treat staphylococcal prosthetic infection
INTRODUCTION
Joint replacement is a common and effective procedure but unfortunately, a small
proportion of patients develop Prosthetic joint Infection (PJI). The bacteria
responsible for these infections exist within a surface -associated community known
as a biofilm. When this biofilm phenotype is expressed, it allows the organisms to
resist phagocytic host defenses, tolerate the stresses induced by antimicrobials and
colonize peri- prosthetic niches. PJI is invariably refractory to standard therapies
and clinicians are required to use a combination of systemic and local
antimicrobials, repeated debridement and prosthesis exchange to treat the patient
resulting in significant morbidity. Standard antibiotic sensitivity tests offer little
insight into bacterial susceptibilities in the biofilm state. Furthermore, they neither
test at the higher levels, nor in the combinations of antibiotics that are commonly
locally delivered during surgery. The aim of this thesis was to develop and validate
a biofilm model, and to use it to test staphylococcal biofilms with clinically
achievable concentrations of antibiotics in combination.METHODS
Sodium alginate gel was chelated with a calcium chloride solution to form bullet
shaped beads with a surface area of 161mm2 These beads were then removed and
their surface inoculated with either a methicillin sensitive Staphylococcus aureus
(ATCC 29213) or a clinical strain of coagulase negative staphylococcus. After being
incubated aerobically for 20 hours in a 48 -well micro -titre plate, growth controls
were sampled and enumerated. The remaining beads were washed to remove non - adherent bacteria and placed into fresh broth containing antibiotics. After 3 hours
of antibiotic challenge, they were removed, washed and the biofilm detached by
dissolving the bead in a citric acid and Na2CO3 solution. Viable organisms were
enumerated after micro -dilution and Miles Misra plating onto agar.RESULTS
Cryo -scanning electron microscopy demonstrated the model allowed a biofilm to
develop on the surface of alginate beads. Overall the technique performed with
satisfactory resemblance of the control data and acceptable responsiveness after
disinfection. The repeatability of disinfection was found to be most variable around
the level used to define bacterial eradication. The model was used to compare the
minimum inhibitory (MIC) and biofilm eradication concentrations (MBEC) of seven
commonly used antibiotics. Poor correlation was found between the susceptibility
of the standard planktonic cultures to antibiotics and those that were effective
against organisms in biofilm. Gentamicin and daptomycin were found to be the
only mono -therapies that were effective against the biofilm at clinically achievable
levels. Combining antibiotics that were ineffective as single agents did not confer
additional benefit.Interestingly despite gentamicin being effective when tested alone, combining it
with clindamycin, rifampacin or linezolid reduced the bactericidal effect markedly
in both strains. This phenomenon was investigated further by varying the
concentration of antibiotics within the combinations. Combining the bactericidal
antibiotics tested with gentamicin had an additive or synergistic effect. More
importantly, a strong antagonistic effect was observed, with between 8 and 32 times
more gentamicin being required, when it was combined with antibiotics considered
bacteriostatic.CONCLUSION
Standard microbiology laboratory testing is inadequate to guide clinical treatment
of PJI. Testing of biofilm susceptibility to combinations of antimicrobials at high
concentrations should be included in the laboratory testing of PJI. Further research
should be directed towards understanding the mechanisms in which bacteriostatic
antibiotics induce the organisms to become more tolerant to other antibiotics.
If the antagonistic effect is confirmed in -vivo then it is logical to study a two stage
antimicrobial strategy, avoiding potential antagonism by only introducing
bacteriostatic agents when the bactericidal drugs dip below their minimum biofilm
eradication concentration
Modeling Oxygen Transport in Three-Dimensional Capillary Networks
The purpose of this thesis was to examine how the use of real 3-dimensional (3D) capillary network geometries affect models of oxygen transport to tissue. Software was developed to reconstruct microvascular geometry in 3D from intravital video. Characterization of 3D reconstructions demonstrated that capillary density, length and capillary diameter were consistent with previous findings. Using reconstructed capillary networks a strategy was devised that utilized red blood cell (RBC) supply rate (SR) as a metric for flow modeling. Applying the RBC SR based flow model on baseline and perturbed flow conditions demonstrated that RBC SR is a major determinant of oxygen delivery that is insensitive to changes in flow distribution. The resulting flow solutions were used for comparing oxygen transport in 3D networks and synthetic parallel arrays. A variety of physiological conditions were simulated and it was determined that parallel arrays resulted in oxygen transport solutions with higher mean PO2 due to homogeneous distribution of vessels in the volume. Lastly, to investigate oxygen transport in a complex pathology a model of sepsis was used to investigate how incremental perfusion loss, consumption increase and change in RBC SR affect oxygen delivery. It was shown that perfusion loss did not markedly impair oxygen delivery provided that RBC SR was maintained. These results have improved our understanding of oxygen transport to tissue in normal and diseased conditions; the use of reconstructed networks and measurements of blood flow & oxygen saturation in computer models provides different solutions than those using statistical averages and synthetic networks
Evolving collective behavior in an artificial ecology
Collective behavior refers to coordinated group motion, common to many animals. The dynamics of a group can be seen as a distributed model, each āanimalā applying the same rule set. This study investigates the use of evolved sensory controllers to produce schooling behavior. A set of artificial creatures āliveā in an artificial world with hazards and food. Each creature has a simple artificial neural network brain that controls movement in different situations. A chromosome encodes the network structure and weights, which may be combined using artificial evolution with another chromosome, if a creature should choose to mate. Prey and predators coevolve without an explicit fitness function for schooling to produce sophisticated, nondeterministic, behavior. The work highlights the role of speciesā physiology in understanding behavior and the role of the environment in encouraging the development of sensory systems
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