63 resultados para radiographic apex


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Over the past 30 years, heathland and open forest communities in south-eastern Australia dominated by Xanthorrhoea australis R.Br. have been severely affected by disease caused by Phytophthora cinnamomi Rands. The disease has caused a sharp decline in numbers of individuals within populations of X. australis; however, the etiology of the disease is unclear. The characteristics and disease symptoms induced by P. cinnamomi were analysed within nine mature X. australis plants that had been removed from the field. Seven plants showed typical disease symptoms that ranged from chlorotic leaves through to plant death. Plants showing disease symptoms had different numbers of infected roots, ranging from 0% in one dead plant, 40% infected roots in a plant showing yellowing of leaf tips and 67 and 86%, respectively, in two plants with severe chlorosis. There was variation within the roots, with some infected close to the stem while others were infected at more distal regions. Within stems of all plants, P. cinnamomi was difficult to isolate but was found in the desmium and stem apex and was associated with massive lesions within the central area of the stem. The symptoms of disease in X. australis are caused by a combination of damage to tissues of the roots and stem that may lead to a reduction in water and mineral transport throughout the plant.

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The paper ponders the location of Gayatri Spivak in the discursive space between Kant and Bimal K. Matilal (but she is also dis-located by her own enactments, disavowals). So it wonders what a postcolonial critique of reason would look like. In the chapter on philosophy, Spivak (1999) develops a sustained critique of just this kind by decoding the works of the 'Three Wise Men of Continental Europe' (Kant, Hegel, Marx), pointing, via the European impact on the Third World, to the ultimate 'foreclosure: [in the fashion of] the native informant'. But the paper detects another triangular imaginary of reason - this time without an apex, and with limited strategies, each deconstructing and challenging the other. Kant is thus important in spite of his own cosmopolitheia, Matilal for his rational realism of 'moral love'. What both fell short of was a genuine critique of the rational, and therefore also of one of its unfortunate beneficiaries, the postcolonial 'informant'; and this critique is Spivak's 'gift'.

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AFTER BALI, OCTOBER 12, 2002, A RANGE OF PUBLIC rituals took place in Australia to remember those who had been killed in the bombing. In Melbourne, the most visible, and collective ritual was the laying of flowers by members of the public on the steps of the State Parliament building, at the highly visible apex of Bourke St. This was a much-publicized event that took place over a period of two weeks. It was a riveting and moving sight/site for many people, who left notes expressing grief and regret, promises of remembrance, and of revenge. The choice of the site, and what would happen there, was prompted by talk-back listeners to Radio 3AW's Nell Mitchell, who called in with many different suggestions as to where and why the laying of flowers should take place. This essay seeks to understand the processes and purposes of the popular, public rituals after Bali, asking who made them, what was made, and how popular--that is, open to formation by those not primarily and directly connected with the mass media and party politics--were the constructions? Further, in calling such an event a "postmodern ritual," the essay will inaugurate an analysis, through cultural studies methodologies, of the attributes of public rituals in contemporary Western cultures.

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Sr2Mg(B03)2 doped with Eu was synthesized respectively in air and weak reducing atmosphere (combustion of carbon particle), whose photoluminescence characteristics and structure were also studied at room-temperature. In air, the fluorescent body's color was white for different synthesized temperatures. At room temperature, the sample was excited and showed red typical emission spectrum of Eu3+ whose emission apex were sharp near 612 nm and emission spect~m was made up of the charge transformation band (CTB) of Eu3 + and excitation spectrum of 4f→4f high energy level transition, then reached the area of VUV. However, under reducing atmosphere (combustion of carbon particles), the color of the sample yielded was yellow, whose color became deeper with increasing temperature and showed phase transition. Using UV excitation, the luminescence of yellow sample was very weak. In a complicated broad spectrum at visible light area, the red emission spectrum of Eu2+ was not observed. Crystal structure and luminescence of the sample were completely different from the results of Diaz and Keszler. Two samples were prepared under oxidation and reducing atmosphere at high temperature, which were different on crystal structure and microstructure. By studying Sr2Mg(B03)2:Eu3+ a series of directional faults or educts were found, because Eu3 + ions substituted for Sr2 + ions. However, microstructure of Sr2Mg(B03 )2: Eu2 + is more complicated, whose excitation spectrum might be excited by Eu2 +. By XRD patten of the samples, phase transitibn could be found. Twins and clusters that were formed from point defect such as interstitial atom and big angle crystal boundary could be found by TEM.

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1. Numerous studies have determined the foraging areas of marine apex predators and investigated their relationship to oceanographic features. Most of these, however, have concentrated on surface-feeding seabirds or epipelagic-foraging marine mammals and there is little information on habitat selection in benthic divers.

2. Satellite telemetry was used during the winters of 2001-2003 to determine the foraging areas of 48 female Australian fur seals (Arctocephalus pusillus doriferus) from four breeding sites in northern Bass Strait whose colonies together represent > 80% of the total species population.

3. All individuals foraged over the shallow continental shelf of Bass Strait supporting earlier studies that suggested the species is an exclusively benthic forager. Individual females showed a high degree of foraging site-fidelity and several foraging 'hot spot' areas could be identified.

4. Analysis of habitat use indicated that individuals selected areas with depths of 60-80 m significantly more (λ = 0.216, P<0.001) than any other bathymetric class. There was also evidence for foraging areas being influenced by SST, with individuals selecting regions of 16.0-16.8 C SST (λ = 0.008, P<0.01), but not surface chlorophyll-a concentration (P> 0.05).

5. Temporal analysis of at-sea movements indicated, due to their primarily benthic foraging mode, the areas frequented by female Australian fur seals did not overlap substantially with areas targeted by commercial fisheries. An exception to this was in far eastern Bass Strait where the Otter Trawl component of the Commonwealth Trawl Sector is highly active over the continental shelf and encompasses the areas frequented by females from The Skerries colony.

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Urban expansion is a principal process threatening biodiversity globally. It is predicted that over half of the world's population will reside in urban centres by 2010. If we are to conserve biodiversity, a shift in perspective from traditional ecological studies based in natural environments, to studies based in less natural environments is paramount. To effectively conserve species which occur in urban environments, comprehensive analysis is necessary to determine the processes that are driving this urban usage. Geographical Information Systems (GIS) technology provides a valuable tool for efficient spatial analysis and predictive mapping of species distributions.

This study used GIS to analyze current breeding sites for the powerful owl, a vulnerable top order predator in urban Melbourne, Australia. GIS analysis suggests that a number of ecological attributes were influencing powerful owl usage of urban environments. Using these ecological attributes, predictive mapping was undertaken, which identified a number of potential breeding sites for powerful owls within urbanized Melbourne.

Urban environments are traditionally perceived as “the wastelands” of natural environments, however, this study demonstrates that they have the potential to support apex predators, an important finding for the management of rare and threatened species.

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Objective
The patellofemoral joint is an example of an incongruent articulation commonly affected by osteoarthritis (OA). The relationship between femoral sulcus angle and the development and progression of patellofemoral OA is unclear. The aim of this study was to examine the relationship between the femoral sulcus angle at baseline and patella cartilage volume at baseline and at 2-year follow-up among community based adults with established knee OA.

Methods
One hundred subjects had magnetic resonance imaging of their symptomatic knee at baseline and at 2-year follow-up. From these images, patella cartilage volume was determined. Radiographic skyline views of the patellofemoral joint were taken at baseline to measure the femoral sulcus angle.

Results
For every 1° increase in the femoral sulcus angle (i.e., as the sulcus angle became more shallow) there was an associated 9.1 mm3 (95% CI 3.1, 15.0) increase in medial patella cartilage volume at baseline (P = 0.003). There was a similar trend that approached statistical significance between the femoral sulcus angle and the lateral patella facet cartilage volume at baseline (P = 0.09). There was no association between the femoral sulcus angle at baseline and the change in patella cartilage volume over 2 years in either patellofemoral compartment.

Conclusion
These results infer that the femoral sulcus angle is a cross-sectional determinant of the amount of patella cartilage, but is not a major determinant of the annual change of patella cartilage volume among people with knee OA. These data suggest that a shallower sulcus in the context of established OA may be an advantageous anatomical variant. Further longitudinal studies are required to determine the role of the femoral sulcus angle in OA.

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Background: Whilst laterally wedged insoles, worn inside the shoes, are advocated as a simple, inexpensive, non-toxic self-administered intervention for knee osteoarthritis (OA), there is currently limited evidence to support their use. The aim of this randomised, double-blind controlled trial is to determine whether laterally wedges insoles lead to greater improvements in knee pain, physical function and health-related quality of life, and slower structural disease progression as well as being more cost-effective, than control flat insoles in people with medial knee OA.

Methods/Design:
Two hundred participants with painful radiographic medial knee OA and varus malalignment will be recruited from the community and randomly allocated to lateral wedge or control insole groups using concealed allocation. Participants will be blinded as to which insole is considered therapeutic. Blinded follow up assessment will be conducted at 12 months after randomisation. The outcome measures are valid and reliable measures recommended for OA clinical trials. Questionnaires will assess changes in pain, physical function and health-related quality-of-life. Magnetic resonance imaging will measure changes in tibial cartilage volume. To evaluate cost-effectiveness, participants will record the use of all health-related treatments in a log-book returned to the assessor on a monthly basis. To test the effect of the intervention using an intention-to-treat analysis, linear regression modelling will be applied adjusting for baseline outcome values and other demographic characteristics.

Discussion: Results from this trial will contribute to the evidence regarding the effectiveness of laterally wedged insoles for the management of medial knee OA.

Trial registration: ACTR12605000503628; NCT00415259.

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Background: Vertebroplasty is a promising but as yet unproven treatment for painful osteoporotic vertebral fractures. It involves radiographic-guided injection of various types of bone cement directly into the vertebral fracture site. Uncontrolled studies and two controlled quasi-experimental before-after studies comparing volunteers who were offered treatment to those who refused it, have suggested an early benefit including rapid pain relief and improved function. Conversely, several uncontrolled studies and one of the controlled before-after studies have also suggested that vertebroplasty may increase the risk of subsequent vertebral fractures, particularly in vertebrae adjacent to treated levels or if cement leakage into the adjacent disc has occurred. As yet, there are no completed randomised controlled trials of vertebroplasty for osteoporotic vertebral fractures. The aims of this participant and outcome assessor-blinded randomised placebo-controlled trial are to i) determine the short-term efficacy and safety (3 months) of vertebroplasty for alleviating pain and improving function for painful osteoporotic vertebral fractures; and ii) determine its medium to longer-term efficacy and safety, particularly the risk of further fracture over 2 years.

Design: A double-blind randomised controlled trial of 200 participants with one or two recent painful osteoporotic vertebral fractures. Participants will be stratified by duration of symptoms (< and ≥ 6 weeks), gender and treating radiologist and randomly allocated to either the treatment or placebo. Outcomes will be assessed at baseline, 1 week, 1, 3, 6, 12 and 24 months. Outcome measures include overall, night and rest pain on 10 cm visual analogue scales, quality of life measured by the Assessment of Quality of Life, Osteoporosis Quality of Life and EQ-5D questionnaires; participant perceived recovery on a 7-point ordinal scale ranging from 'a great deal worse' to 'a great deal better'; disability measured by the Roland-Morris Disability Questionnaire; timed 'Up and Go' test; and adverse effects. The presence of new fractures will be assessed by radiographs of the thoracic and lumbar spine performed at 12 and 24 months.

Discussion:
The results of this trial will be of major international importance and findings will be immediately translatable into clinical practice.

Trial registration:
Australian Clinical Trial Register # [ACTRN012605000079640]

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Background The aim of this study was to identify specific bone characteristics of stress fracture (SF) cases in sportswomen. To date, no tool is able to distinguish individuals who are at risk, limiting preventive measures.

Material and methods We investigated the skeletal system of sportswomen who did sustain SF in the past (n = 19) and compared it with that of female controls (C) with a similar sporting history but without any fracture history (n = 20).

Bone mass and body composition were measured using dual-energy X-ray absorptiometry. Bone micro-architecture was investigated by calcaneal ultrasound and fractal analysis of calcaneus radiographic images. Oestradiol levels were measured by E.I.A, and IGF-1 by R.I.A. Menstrual characteristics, nutrient intake, and training were assessed using questionnaires.

Results The result of the fractal analysis, expressed by the Hmean parameter, was significantly lower in the SF group, reflecting a more complex structure of the trabecular micro-architectural organization (P < 0·005). Body mass index (BMI) at birth was also found to be lower in the SF cases as compared with their C (P < 0·03).

Multivariate analysis revealed that the fractal parameter Hmean, bone mineral content (BMC) at Ward's triangle and the BMI at birth correctly assigned 84·85% of the female athletes into their respective SF or C groups (P = 0·001).

Conclusion These results suggest that the fractal parameter and the BMI at birth may be able to identify female athletes most at risk for this overuse bone injury, as their low indexes might reflect a greater skeletal sensitivity.

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In recent times there has been growing interest in the integration of solar collectors, for water heating, into the façade of buildings. However, the design methodology of these devices remains largely the same as typical “stand-alone” collectors. As such it is still common for materials with a high thermal resistance to be used for insulating the rear surface of these collectors.

Unlike a “stand-alone” solar collector that is exposed to the atmosphere at all faces; a building integrated system allows the opportunity for air to act as an insulator at the rear surface of the solar collector. The use of convection suppression devices has been widely discussed in the literature as a means of reducing natural convection heat loss from the front surface of glazed solar collectors. However in this study the use of baffles in an attic was examined as a means of suppressing heat loss by natural convection from the rear surface of a roof-integrated solar collector. The aim of the study was to examine whether the use of baffles would allow the cost of building integrated collectors to be reduced by removing the cost of insulating material.

To determine the effect of baffles in the attic space at the rear surface of the collector, a 3-dimensional triangular cross sectioned enclosure with a vertical aspect ratio of 0.5 and a horizontal aspect ratio of 3.3 was modelled. The flow patterns and heat transfer in the enclosure were determined for Grashof Numbers in the range of 106 to 107 using a commercially available finite volume CFD solver.
It was found that the use of a single adiabatic baffle mounted vertically downwards from the apex, and extending the length of the enclosure, would alter the flow such that the heat transfer due to natural convection was reduced with respect to the length of the baffle.

Furthermore, it was observed that a series of convection cells, not previously reported in the literature, appeared to exist along the length of the enclosure. As such, it may be possible to derive additional benefit in reducing the heat transfer by adding lateral baffles in addition to the single longitudinal baffle modelled in this study.

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The Universiti Sains Malaysia APEX program is an attempt to engage the difficult and complex problems of competition, moral leadership and responsibility in Malaysian education. This paper discusses and gives an analysis of some central issues with regards to USM’s reform agenda. I seek to place the USM project within a broader debate over the nature of reform and the possibilities of business unusual in the Malaysian and global environment. The paper is part of a broader project of theorization of USM in the context of understanding what APEX is and how it truly offers a new and vigorous engagement with the problems of higher education in Malaysia.

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Malaysian Higher educational reform is an important and central aspect of the broader Malaysian public policy focus on excellence, development and national growth. This proposed paper intends to discuss analyze and critique the APEX program for Malaysian Universities. In particular the paper will investigate and discuss the way Universiti Sains Malaysia has interpreted and developed its strategic goals in light of its award of APEX status. Specifically I intend to discuss the strengths and limitations of the Universiti Sains Malaysia agenda, and contextualize it within a broader discussion about the directions of Malaysian Higher Education, in conditions of globalization, network society, and the knowledge economy. The challenges faced by the reform agenda at USM are significant and it is important that any understanding of the USM agenda be informed by deep reflection on the underlying philosophical aims and justifications for its direction. In this way my paper will attempt to show how the USM project is both an important part of Malaysian national development and a critical response to contemporary globalization, while at the same time an innovative and challenging intervention into public policy debate in Higher Education. The values and objectives of USM in regards to its strategic reorientation have implications far beyond the Higher Education sector and these implications will also be discussed.

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Malaysian Higher educational reform is an important and central aspect of the broader Malaysian public policy focus on excellence, development and national growth. This proposed paper intends to discuss analyze and critique the APEX program for Malaysian Universities. In particular the paper will investigate and discuss the way Universiti Sains Malaysia has interpreted and developed its strategic goals in light of its award of APEX status. Specifically I intend to discuss the strengths and limitations of the Universiti Sains Malaysia agenda, and contextualize it within a broader discussion about the directions of Malaysian Higher Education, in conditions of globalization, network society, and the knowledge economy. The challenges faced by the reform agenda at USM are significant and it is important that any understanding of the USM agenda be informed by deep reflection on the underlying philosophical aims and justifications for its direction. In this way my paper will attempt to show how the USM project is both an important part of Malaysian national development and a critical response to contemporary globalization, while at the same time an innovative and challenging intervention into public policy debate in Higher Education. The values and objectives of USM in regards to its strategic reorientation have implications far beyond the Higher Education sector and these implications will also be discussed.

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There is growing recognition of the important roles played by predators in regulating ecosystems and sustaining biodiversity. Much attention has focused on the consequences of predator-regulation of herbivore populations, and associated trophic cascades. However apex predators may also control smaller ‘mesopredators’ through intraguild interactions. Removal of apex predators can result in changes to intraguild interactions and outbreaks of mesopredators (‘mesopredator release’), leading in turn to increased predation on smaller prey. Here we provide a review and synthesis of studies of predator interactions, mesopredator release and their impacts on biodiversity. Mesopredator suppression by apex predators is widespread geographically and taxonomically. Apex predators suppress mesopredators both by killing them, or instilling fear, which motivates changes in behaviour and habitat use that limit mesopredator distribution and abundance. Changes in the abundance of apex predators may have disproportionate (up to fourfold) effects on mesopredator abundance. Outcomes of interactions between predators may however vary with resource availability, habitat complexity and the complexity of predator communities. There is potential for the restoration of apex predators to have benefits for biodiversity conservation through moderation of the impacts of mesopredators on their prey, but this requires a whole-ecosystem view to avoid unforeseen negative effects.

‘Nothing has changed since I began.

My eye has permitted no change.

I am going to keep things like this.’

From ‘Hawk Roosting’, by Ted Hughes.