127 resultados para 190-1175


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Fractional order dynamics in physics, particularly when applied to diffusion, leads to an extension of the concept of Brown-ian motion through a generalization of the Gaussian probability function to what is termed anomalous diffusion. As MRI is applied with increasing temporal and spatial resolution, the spin dynamics are being examined more closely; such examinations extend our knowledge of biological materials through a detailed analysis of relaxation time distribution and water diffusion heterogeneity. Here the dynamic models become more complex as they attempt to correlate new data with a multiplicity of tissue compartments where processes are often anisotropic. Anomalous diffusion in the human brain using fractional order calculus has been investigated. Recently, a new diffusion model was proposed by solving the Bloch-Torrey equation using fractional order calculus with respect to time and space (see R.L. Magin et al., J. Magnetic Resonance, 190 (2008) 255-270). However effective numerical methods and supporting error analyses for the fractional Bloch-Torrey equation are still limited. In this paper, the space and time fractional Bloch-Torrey equation (ST-FBTE) is considered. The time and space derivatives in the ST-FBTE are replaced by the Caputo and the sequential Riesz fractional derivatives, respectively. Firstly, we derive an analytical solution for the ST-FBTE with initial and boundary conditions on a finite domain. Secondly, we propose an implicit numerical method (INM) for the ST-FBTE, and the stability and convergence of the INM are investigated. We prove that the implicit numerical method for the ST-FBTE is unconditionally stable and convergent. Finally, we present some numerical results that support our theoretical analysis.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Study Design. Analysis of a case series of 24 Lenke 1C adolescent idiopathic scoliosis (AIS) patients receiving selective thoracoscopic anterior scoliosis correction. Objective. To report the behaviour of the compensatory lumbar curve in a group of Lenke IC AIS patients following thoracoscopic anterior scoliosis correction, and to compare the results of this study with previously published data. Summary of Background Data. Several prior studies have reported spontaneous lumbar curve correction for both anterior and posterior selective fusion in Lenke 1C/King-Moe II patients; however to our knowledge no previous studies have reported outcomes of thoracoscopic anterior correction for this curve type. Methods. All AIS patients with a curve classification of Lenke 1C and a minimum of 24 months follow-up were retrieved from a consecutive series of 190 AIS patients who underwent thoracoscopic anterior instrumented fusion. Cobb angles of the major curve, instrumented levels, compensatory lumbar curve, and T5-T12 kyphosis were recorded, as well as coronal spinal balance, T1 tilt angle and shoulder balance. All radiographic parameters were measured before surgery and at 2, 6, 12 and 24 months after surgery. Results. Twenty-four female patients with right thoracic curves had a mean thoracic Cobb angle of 53.0° before surgery, decreasing to 24.9° two years after surgery. The mean lumbar compensatory Cobb angle was 43.5° before surgery, spontaneously correcting to 25.4° two years after surgery, indicating balance between the thoracic and lumbar scoliotic curves. The lumbar correction achieved (41.8%) compares favourably to previous studies. Conclusions. Selective thoracoscopic anterior fusion allows spontaneous lumbar curve correction and achieves coronal balance of main thoracic and compensatory lumbar curves, good cosmesis and patient satisfaction. Correction and balance are maintained 24 months after surgery.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Paraffin sections from 190 epithelial ovarian tumours, including 159 malignant and 31 benign epithelial tumours, were analysed immunohistochemically for expression of cyclin-dependent kinase inhibitor 2 (CDKN2A) gene product p16INK4A (p16). Most benign tumours showed no p16 expression in the tumour cells, whereas only 11% of malignant cancers were p16 negative. A high proportion of p16-positive tumour cells was associated with advanced stage and grade, and with poor prognosis in cancer patients. For FIGO stage 1 tumours, a high proportion of p16-positive tumour cells was associated with poorer survival, suggesting that accumulation of p16 is an early event of ovarian tumorigenesis. In contrast to tumour cells, high expression of p16 in the surrounding stromal cells was not associated with the stage and grade, but was associated with longer survival. When all parameters were combined in multivariate analysis, high p16 expression in stromal cells was not an independent predictor for survival, indicating that low p16 expression in stromal cells is associated with other markers of tumour progression. High expression of p16 survival in the stromal cells of tumours from long-term survivors suggests that tumour growth is limited to some extent by factors associated with p16 expression in the matrix.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Aim. A protocol for a new peer-led self-management programme for communitydwelling older people with diabetes in Shanghai, China. Background. The increasing prevalence of type 2 diabetes poses major public health challenges. Appropriate education programmes could help people with diabetes to achieve self-management and better health outcomes. Providing education programmes to the fast growing number of people with diabetes present a real challenge to Chinese healthcare system, which is strained for personnel and funding shortages. Empirical literature and expert opinions suggest that peer education programmes are promising. Design. Quasi-experimental. Methods. This study is a non-equivalent control group design (protocol approved in January, 2008). A total of 190 people, with 95 participants in each group, will be recruited from two different, but similar, communities. The programme, based on Social Cognitive Theory, will consist of basic diabetes instruction and social support and self-efficacy enhancing group activities. Basic diabetes instruction sessions will be delivered by health professionals, whereas social support and self-efficacy enhancing group activities will be led by peer leaders. Outcome variables include: self-efficacy, social support, self-management behaviours, depressive status, quality of life and healthcare utilization, which will be measured at baseline, 4 and 12 weeks. Discussion. This theory-based programme tailored to Chinese patients has potential for improving diabetes self-management and subsequent health outcomes. In addition, the delivery mode, through involvement of peer leaders and existing community networks,is especially promising considering healthcare resource shortage in China.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The mineral beryllonite has been characterized by the combination of Raman spectroscopy and infrared spectroscopy. SEM–EDX was used for the chemical analysis of the mineral. The intense sharp Raman band at 1011 cm-1, was assigned to the phosphate symmetric stretching mode. Raman bands at 1046, 1053, 1068 and the low intensity bands at 1147, 1160 and 1175 cm-1 are attributed to the phosphate antisymmetric stretching vibrations. The number of bands in the antisymmetric stretching region supports the concept of symmetry reduction of the phosphate anion in the beryllonite structure. This concept is supported by the number of bands found in the out-of-plane bending region. Multiple bands are also found in the in-plane bending region with Raman bands at 399, 418, 431 and 466 cm-1. Strong Raman bands at 304 and 354 cm-1 are attributed to metal oxygen vibrations. Vibrational spectroscopy served to determine the molecular structure of the mineral. The pegmatitic phosphate minerals such as beryllonite are more readily studied by Raman spectroscopy than infrared spectroscopy.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In order to comprehend user information needs by concepts, this paper introduces a novel method to match relevance features with ontological concepts. The method first discovers relevance features from user local instances. Then, a concept matching approach is developed for matching these features to accurate concepts in a global knowledge base. This approach is significant for the transition of informative descriptor and conceptional descriptor. The proposed method is elaborately evaluated by comparing against three information gathering baseline models. The experimental results shows the matching approach is successful and achieves a series of remarkable improvements on search effectiveness.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This study explored the flexural performance of an innovative Hybrid Composite Floor Plate System (HCFPS), comprised of Polyurethane (PU) core, outer layers of Glass-fibre Reinforced Cement (GRC) and steel laminates at tensile regions, using experimental testing and Finite Element (FE) modelling. Bending and cyclic loading tests for the HCFPS panels and a comprehensive material testing program for component materials were carried out. HCFPS test panel exhibited ductile behaviour and flexural failure with a deflection ductility index of 4. FE models of HCFPS were developed using the program ABAQUS and validated with experimental results. The governing criteria of stiffness and flexural performance of HCFPS can be improved by enhancing the properties of component materials. HCFPS is 50-70% lighter in weight when compared to conventional floor systems. This study shows that HCFPS can be used for floor structures in commercial and residential buildings as an alternative to conventional steel concrete composite systems.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This paper presents the details of numerical studies on the shear behaviour and strength of lipped channel beams (LCBs) with stiffened web openings. Over the last couple of decades, cold-formed steel beams have been used extensively in residential, industrial and commercial buildings as primary load bearing structural components. Their shear strengths are considerably reduced when web openings are included for the purpose of locating building services. Our research has shown that shear strengths of LCBs were reduced by up to 70% due to the inclusion of web openings. Hence there is a need to improve the shear strengths of LCBs with web openings. A cost effective way to improve the detrimental effects of a large web opening is to attach appropriate stiffeners around the web openings in order to restore the original shear strength and stiffness of LCBs. Hence numerical studies were undertaken to investigate the shear strengths of LCBs with stiffened web openings. In this research, finite element models of LCBs with stiffened web openings in shear were developed to simulate the shear behaviour and strength of LCBs. Various stiffening methods using plate and LCB stud stiffeners attached to LCBs using screw-fastening were attempted. The developed models were then validated by comparing their results with experimental results and used in parametric studies. Both finite element analysis and experimental results showed that the stiffening arrangements recommended by past re-search for cold-formed steel channel beams are not adequate to restore the shear strengths of LCBs with web openings. Therefore new stiffener arrangements were proposed for LCBs with web openings based on experimental and finite element analysis results. This paper presents the details of finite element models and analyses used in this research and the results including the recommended stiffener arrangements.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

With the growth in project management as a form of work organisation in many sectors of the economy has come the significant rise in the number of project managers and project team members. This change in work organisation brings issues in forging career paths and determining career support in work situations that are often dynamic, short lived and intense. In the relatively small but substantially robust Australian economy, a unique labour market and the tyranny of distance bring their own difficulties. Innovative and collaborative project structures and increasing prevalence of contract work provide both challenges and opportunities for new career pathways in many industries. A growing percentage of Australia's workforce is employed in project-based or project-oriented organisations, leading to the claim that Australia is a project-based economy. This provided a context for our research into the career paths and the issues of career management for project managers working in a project based economy. Using in-depth interviews with project managers from three industry areas we found generational and gender differences in experiences of work, workplace support and mentoring for career development. For a continued strong performance in this economy,organisations that employ project personnel will need to consider how they will ensure the supply of high quality project professionals into the future.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Introduction: Lower limb function in hurdling is patently asymmetrical. The lead limb undertakes the preparatory and landing steps while the trail limb contends with the hurdle and recovery steps. Discrete loading profiles of these steps will reflect the asymmetrical function and may provide useful insight into injury mechanisms. A pilot study was undertaken to determine the loading profiles of the hurdle, landing and recovery steps of elite male hurdlers. Equivalent data for steps between hurdles, where the running action is more symmetrical, were used for the purpose of comparison, simultaneously minimising the confounding effect of speed. Methodology: In-shoe pressures were recorded (FScan, 200 Hz) for four elite male hurdlers while they completed a routine hurdle drill at a self-selected fast but sub-race speed. The drill comprised of three consecutive hurdles. Data for the hurdle, landing and recovery steps of the first and second hurdles, along with data for the running steps between hurdles 1 and 2, and 2 and 3, were used for the purpose of analysis. Peak pressures within 1cm2 masks were determined for the hallux, first, central and fifth metatarsals (T1, M1, M2–4 and M5 respectively). Peak pressure (kPa) and loading duration (ms) for the hurdle, landing and recovery steps are reported as a percentage of the respective limb-matched values for between-hurdle steps. Results/discussion: For between-hurdle steps, T1, M1 and M2–4 peak pressures were 312/357, 356/306 and 362/368 kPa, lead/trail limbs respectively. For the hurdle, landing and recovery steps, pressures at T1 and M1 increased. For T1 the increases were in the order of 17%, 36% and 8% (hurdle, landing and recovery steps, respectively) while the corresponding increases at M1 were 7%, 54% and 20%. Pressures at M2–4 were similar for all steps, while M5 loaded erratically. For the between-hurdle steps, the loading durations at T1, M1 and M2–4, were 160/162, 170/142 and 190/191 ms, respectively. For the landing step, loading duration decreased for T1, M1and M2–4 (−8%, −19% and −18%, respectively). In the hurdle step, loading duration decreased for the metatarsals but not for T1. Conclusions: The hurdling action leads to regional pressure increases that act for shorter durations in comparison to the between-hurdle running steps. These changes are most notable at the first metatarsal, a common site of foot injury.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In Angus v Conelius [2007] QCA 190 the Queensland Court of Appeal concluded that the obligations under the Motor Accident Insurance Act 1994 (Qld), and in particular s 45 of the Act (duty of claimant to cooperate with insurer), continue beyond the commencement of court proceedings

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Gaelic Games are the indigenous sports played in Ireland, the most popular being Gaelic football and hurling. The games are contact sports and the physical demands are thought to be similar to those of Australian Rules football, rugby union, rugby league, field hockey, and lacrosse (Delahunt et al., 2011). The difference in chronological age between children in a single age group is known as relative age and its consequences as the RAE, whereby younger players are disadvantaged (Del Campo et al., 2010). The purpose of this study was to describe the physical and performance profile of sub-elite juvenile Gaelic Games players and to establish if a RAE is present in this cohort and any influence physiological moderator variables may have on this. Following receipt of ethical approval (EHSREC11-45), six sub-elite county development squads (Under-14/15/16 age groups, male, n=115) volunteered to partake in the study. Anthropometric data including skin folds and girths were collected. A number of field tests of physical performance including 5 and 20m speed, vertical and broad jump distance, and an estimate of VO2max were carried out. Descriptive data are presented as Mean SD. Juvenile sub-elite Gaelic Games players aged 14.53 0.82 y were 172.87 7.63 cm tall, had a mass of 64.74 11.06 kg, a BMI of 21.57 2.82 kg.m-2 and 9.22 4.78 % body fat. Flexibility, measured by sit and reach was 33.62 6.86 cm and lower limb power measured by vertical and broad jump were 42.19 5.73 and 191.16 25.26 cm, respectively. Participant time to complete 5m, 20m and an agility test (T-Test) was 1.12 0.07, 3.31 0.30 and 9.31 0.55 s respectively. Participant’s estimated VO2max was 48.23 5.05 ml.kg.min-1. Chi-Square analysis of birth month by quartile (Q1 = January-March) revealed that a RAE was present in this cohort, whereby an over-representation of players born in Q1 compared with Q2, Q3 and Q4 was evident (2 = 14.078, df = 3, p = 0.003). Kruskal-Wallis analysis of the data revealed no significant difference in any of the performance parameters based on quartile of birth (Alpha level = 0.05).This study provides a physical performance profile of juvenile sub-elite Gaelic Games players, comparable with those of other sports such as soccer and rugby. This novel data can inform us of the physical requirements of the sport. The evidence of a RAE is similar to that observed in other contact sports such as soccer and rugby league (Carling et al, 2009; Till et al, 2010). Although a RAE exists in this cohort, this cannot be explained by any physical/physiological moderator variables. Carling C et al. (2009). Scandinavian Journal of Medicine and Science in Sport 19, 3-9. Delahunt E et al. (2011). Journal of Athletic Training 46, 241-5. Del Campo DG et al. (2010). Journal of Sport Science and Medicine 9, 190-198. Delorme N et al. (2010). European Journal of Sport Science 10, 91-96. Till K et al. (2010). Scandinavian Journal of Medicine and Science in Sports 20, 320-329.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In Social Science (Organization Studies, Economics, Management Science, Strategy, International Relations, Political Science…) the quest for addressing the question “what is a good practitioner?” has been around for centuries, with the underlying assumptions that good practitioners should lead organizations to higher levels of performance. Hence to ask “what is a good “captain”?” is not a new question, we should add! (e.g. Tsoukas & Cummings, 1997, p. 670; Söderlund, 2004, p. 190). This interrogation leads to consider problems such as the relations between dichotomies Theory and Practice, rigor and relevance of research, ways of knowing and knowledge forms. On the one hand we face the “Enlightenment” assumptions underlying modern positivist Social science, grounded in “unity-of-science dream of transforming and reducing all kinds of knowledge to one basic form and level” and cause-effects relationships (Eikeland, 2012, p. 20), and on the other, the postmodern interpretivist proposal, and its “tendency to make all kinds of knowing equivalent” (Eikeland, 2012, p. 20). In the project management space, this aims at addressing one of the fundamental problems in the field: projects still do not deliver their expected benefits and promises and therefore the socio-economical good (Hodgson & Cicmil, 2007; Bredillet, 2010, Lalonde et al., 2012). The Cartesian tradition supporting projects research and practice for the last 60 years (Bredillet, 2010, p. 4) has led to the lack of relevance to practice of the current conceptual base of project management, despite the sum of research, development of standards, best & good practices and the related development of project management bodies of knowledge (Packendorff, 1995, p. 319-323; Cicmil & Hodgson, 2006, p. 2–6, Hodgson & Cicmil, 2007, p. 436–7; Winter et al., 2006, p. 638). Referring to both Hodgson (2002) and Giddens (1993), we could say that “those who expect a “social-scientific Newton” to revolutionize this young field “are not only waiting for a train that will not arrive, but are in the wrong station altogether” (Hodgson, 2002, p. 809; Giddens, 1993, p. 18). While, in the postmodern stream mainly rooted in the “practice turn” (e.g. Hällgren & Lindahl, 2012), the shift from methodological individualism to social viscosity and the advocated pluralism lead to reinforce the “functional stupidity” (Alvesson & Spicer, 2012, p. 1194) this postmodern stream aims at overcoming. We suggest here that addressing the question “what is a good PM?” requires a philosophy of practice perspective to complement the “usual” philosophy of science perspective. The questioning of the modern Cartesian tradition mirrors a similar one made within Social science (Say, 1964; Koontz, 1961, 1980; Menger, 1985; Warry, 1992; Rothbard, 1997a; Tsoukas & Cummings, 1997; Flyvbjerg, 2001; Boisot & McKelvey, 2010), calling for new thinking. In order to get outside the rationalist ‘box’, Toulmin (1990, p. 11), along with Tsoukas & Cummings (1997, p. 655), suggests a possible path, summarizing the thoughts of many authors: “It can cling to the discredited research program of the purely theoretical (i.e. “modern”) philosophy, which will end up by driving it out of business: it can look for new and less exclusively theoretical ways of working, and develop the methods needed for a more practical (“post-modern”) agenda; or it can return to its pre-17th century traditions, and try to recover the lost (“pre-modern”) topics that were side-tracked by Descartes, but can be usefully taken up for the future” (Toulmin, 1990, p. 11). Thus, paradoxically and interestingly, in their quest for the so-called post-modernism, many authors build on “pre-modern” philosophies such as the Aristotelian one (e.g. MacIntyre, 1985, 2007; Tsoukas & Cummings, 1997; Flyvbjerg, 2001; Blomquist et al., 2010; Lalonde et al., 2012). It is perhaps because the post-modern stream emphasizes a dialogic process restricted to reliance on voice and textual representation, it limits the meaning of communicative praxis, and weaking the practice because it turns away attention from more fundamental issues associated with problem-definition and knowledge-for-use in action (Tedlock, 1983, p. 332–4; Schrag, 1986, p. 30, 46–7; Warry, 1992, p. 157). Eikeland suggests that the Aristotelian “gnoseology allows for reconsidering and reintegrating ways of knowing: traditional, practical, tacit, emotional, experiential, intuitive, etc., marginalised and considered insufficient by modernist [and post-modernist] thinking” (Eikeland, 2012, p. 20—21). By contrast with the modernist one-dimensional thinking and relativist and pluralistic post-modernism, we suggest, in a turn to an Aristotelian pre-modern lens, to re-conceptualise (“re” involving here a “re”-turn to pre-modern thinking) the “do” and to shift the perspective from what a good PM is (philosophy of science lens) to what a good PM does (philosophy of practice lens) (Aristotle, 1926a). As Tsoukas & Cummings put it: “In the Aristotelian tradition to call something good is to make a factual statement. To ask, for example, ’what is a good captain’?’ is not to come up with a list of attributes that good captains share (as modem contingency theorists would have it), but to point out the things that those who are recognized as good captains do.” (Tsoukas & Cummings, 1997, p. 670) Thus, this conversation offers a dialogue and deliberation about a central question: What does a good project manager do? The conversation is organized around a critic of the underlying assumptions supporting the modern, post-modern and pre-modern relations to ways of knowing, forms of knowledge and “practice”.