959 resultados para Newton Principia fondamenti meccanica classica
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Growing community concerns about the ecological, social, cultural and economic impact of housing and urban projects poses new challenges for those who have to deliver them. It is important that these concerns are addressed as part of the community engagement processes on projects. Community engagement is traditionally perceived as the purview of planners and disconnected from the building construction process. This is despite most project approval processes mandating on-going community engagement over the project’s entire lifetime. There is evidence that point to a culture of ambiguity and ambivalence among building professionals about their roles, responsibilities and expectations of community engagement during the construction phase of projects. This has contributed to a culture of distrust between communities and the construction industry. There is a clear need to build capacity among building professionals to empower them as active participants in community engagement processes which can promote better project outcomes and minimise delays and conflicts. This paper describes a process that utilises the Theory of Planned Behaviour as a framework to equip building professionals with the skills they need to engage effectively with local communities during the construction phase of projects.
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This study examined the effect of 20 weeks resistance training on a range of serum hormones and inflammatory markers at rest, and following acute bouts of exercise in prostate cancer patients undergoing androgen deprivation. Ten patients exercised twice weekly at high intensity for several upper and lower-body muscle groups. Neither testosterone nor prostate-specific antigen changed at rest or following an acute bout of exercise. However, serum growth hormone (GH), dehydroepiandrosterone (DHEA), interleukin-6, tumor necrosis factor-alpha and differential blood leukocyte counts increased (P < 0.05) following acute exercise. Resistance exercise does not appear to compromise testosterone suppression, and acute elevations in serum GH and DHEA may partly underlie improvements observed in physical function.
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The aims of this study were to examine the plasma concentrations of inflammatory mediators including cytokines induced by a single bout of eccentric exercise and again 4 weeks later by a second bout of eccentric exercise of the same muscle group. Ten untrained male subjects performed two bouts of the eccentric exercise involving the elbow flexors (6 sets of 5 repetitions) separated by four weeks. Changes in muscle soreness, swelling, and function following exercise were compared between the bouts. Blood was sampled before, immediately after, 1 h, 3 h, 6 h, 24 h (1 d), 48 h (2 d), 72 h (3 d), 96 h (4 d) following exercise bout to measure plasma creatine kinase (CK) activity, plasma concentrations of myoglobin (Mb), interleukin (IL)-1beta, IL-1 receptor antagonist (IL-1ra), IL-4, IL-6, IL-8, IL-10, IL-12p40, tumor necrosis factor (TNF)-alpha, granulocyte colony-stimulating factor (G-CSF), myeloperoxidase (MPO), prostaglandin E2 (PGE2), heat shock protein (HSP) 60 and 70. After the first bout, muscle soreness increased significantly, and there was also significant increase in upper arm circumference; muscle function decreased and plasma CK activity and Mb concentration increased significantly. These changes were significantly smaller after the second bout compared to the first bout, indicating muscle adaptation to the repeated bouts of the eccentric exercise. Despite the evidence of greater muscle damage after the first bout, the changes in cytokines and other inflammatory mediators were quite minor, and considerably smaller than that following endurance exercise. These results suggest that eccentric exercise-induced muscle damage is not associated with the significant release of cytokines into the systemic circulation. After the first bout, plasma G-CSF concentration showed a small but significant increase, whereas TNF-alpha and IL-8 showed significant decreases compared to the pre-exercise values. After the second bout, there was a significant increase in IL-10, and a significant decrease in IL-8. In conclusion, although there was evidence of severe muscle damage after the eccentric exercise, this muscle damage was not accompanied by any large changes in plasma cytokine concentrations. The minor changes in systemic cytokine concentration found in this study might reflect more rapid clearance from the circulation, or a lack of any significant metabolic or oxidative demands during this particular mode of exercise. In relation to the adaptation to the muscle damage, the anti-inflammatory cytokine IL-10 might work as one of the underlying mechanisms of action.
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The objective of this PhD research program is to investigate numerical methods for simulating variably-saturated flow and sea water intrusion in coastal aquifers in a high-performance computing environment. The work is divided into three overlapping tasks: to develop an accurate and stable finite volume discretisation and numerical solution strategy for the variably-saturated flow and salt transport equations; to implement the chosen approach in a high performance computing environment that may have multiple GPUs or CPU cores; and to verify and test the implementation. The geological description of aquifers is often complex, with porous materials possessing highly variable properties, that are best described using unstructured meshes. The finite volume method is a popular method for the solution of the conservation laws that describe sea water intrusion, and is well-suited to unstructured meshes. In this work we apply a control volume-finite element (CV-FE) method to an extension of a recently proposed formulation (Kees and Miller, 2002) for variably saturated groundwater flow. The CV-FE method evaluates fluxes at points where material properties and gradients in pressure and concentration are consistently defined, making it both suitable for heterogeneous media and mass conservative. Using the method of lines, the CV-FE discretisation gives a set of differential algebraic equations (DAEs) amenable to solution using higher-order implicit solvers. Heterogeneous computer systems that use a combination of computational hardware such as CPUs and GPUs, are attractive for scientific computing due to the potential advantages offered by GPUs for accelerating data-parallel operations. We present a C++ library that implements data-parallel methods on both CPU and GPUs. The finite volume discretisation is expressed in terms of these data-parallel operations, which gives an efficient implementation of the nonlinear residual function. This makes the implicit solution of the DAE system possible on the GPU, because the inexact Newton-Krylov method used by the implicit time stepping scheme can approximate the action of a matrix on a vector using residual evaluations. We also propose preconditioning strategies that are amenable to GPU implementation, so that all computationally-intensive aspects of the implicit time stepping scheme are implemented on the GPU. Results are presented that demonstrate the efficiency and accuracy of the proposed numeric methods and formulation. The formulation offers excellent conservation of mass, and higher-order temporal integration increases both numeric efficiency and accuracy of the solutions. Flux limiting produces accurate, oscillation-free solutions on coarse meshes, where much finer meshes are required to obtain solutions with equivalent accuracy using upstream weighting. The computational efficiency of the software is investigated using CPUs and GPUs on a high-performance workstation. The GPU version offers considerable speedup over the CPU version, with one GPU giving speedup factor of 3 over the eight-core CPU implementation.
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Occupational stress research has consistently demonstrated many negative effects of work stressors on employee adjustment (i.e., job-related attitudes and health). Considerable literature also describes potential moderators of this relationship. While research has revealed that leader vision can have significant positive effects on employee adjustment it has neglected investigation of its potential stress buffering effects. Based on leadership and identification theories, it was predicted that stress buffering effects of leader vision would be more evident for distal versus proximal leaders and also when the distal or proximal leader vision was congruent with the employee adjustment outcome type (distal versus proximal). Predictions were tested with an employee sample from one large public sector organization (N = 519). Hierarchical multiple regression analyses revealed that main and moderated effects relating to leader vision supported the notion that occupational stress would be reduced when there was congruence of distal and proximal leader vision and distal and proximal outcome types. However, stress buffering effects were found for high and low perceivers of leader vision that were not in line with hypotheses posing questions for the definitions of distal and proximal identifications. Findings are discussed in terms of theoretical and practical implications.
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A range of authors from the risk management, crisis management, and crisis communications literature have proposed different models as a means of understanding components of crisis. A generic component of these sources has focused on preparedness practices before disturbance events and response practices during events. This paper provides a critical analysis of three key explanatory models of how crises escalate highlighting the strengths and limitations of each approach. The paper introduces an optimised conceptual model utilising components from the previous work under the four phases of pre-event, response, recovery, and post-event. Within these four phases, a ten step process is introduced that can enhance understanding of the progression of distinct stages of disturbance for different types of events. This crisis evolution framework is examined as a means to provide clarity and applicability to a range of infrastructure failure contexts and provide a path for further empirical investigation in this area.
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The recent spate of natural disasters across Australia has led to an outpouring of spontaneous volunteering, both formally through nonprofit and government agencies and informally through local community and online networks. Relatively little is understood about the motivations and characteristics of spontaneous volunteers. The aims of this project were to: Examine the characteristics and motivations of spontaneous volunteers who respond to a crisis event; Illuminate the effects of spontaneous volunteering on personal, social and civic networks; Explicate the conditions under which sustained volunteering and other forms of civic engagement arise from spontaneous volunteering and; Consider the practical implications of these findings for organisations involved in coordinating volunteers both with and beyond disaster events.
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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”.
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This study aims to identify and categorize barriers to e-learning adoption and the relative impact of those barriers on learners. It contributes to the understanding of learner perceptions of barriers, the different types of barriers and their relative importance. This study used a quantitative methodology grounded in previous literature. The study is based on a self-administered questionnaire conducted with employees in a rail organisation. This research demonstrates there are three key factors that represent barriers to e-learning: the nature of e-learning as a learning approach, the use of technology, and concerns about lack of time and potential interruptions when trying to complete e-learning.
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Aim To examine the mediating effect of coping strategies on the consequences of nursing and non-nursing (administrative) stressors on the job satisfaction of nurses during change management. Background Organisational change can result in an increase in nursing and nonnursing- related stressors, which can have a negative impact on the job satisfaction of nurses employed in health-care organisations. Method Matched data were collected in 2009 via an online survey at two timepoints (six months apart). Results Partial least squares path analysis revealed a significant causal relationship between Time 1 administrative and role stressors and an increase in nursing-specific stressors in Time 2. A significant relationship was also identified between job-specific nursing stressors and the adoption of effective coping strategies to deal with increased levels of change-induced stress and strain and the likelihood of reporting higher levels of job satisfaction in Time 2. Conclusions The effectiveness of coping strategies is critical in helping nurses to deal with the negative consequences of organisational change. Implications for nursing management This study shows that there is a causal relationship between change, non-nursing stressors and job satisfaction. Senior management should implement strategies aimed at reducing nursing and nonnursing stress during change in order to enhance the job satisfaction of nurses. Keywords: Australia, change management, job satisfaction, nursing and non-nursing stressors, public and non-profit sector
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Recent developments in wearable ECG technology have seen renewed interest in the use of Heart Rate Variability (HRV) feedback for stress management. Yet, little is know about the efficacy of such interventions. Positive reappraisal is an emotion regulation strategy that involves changing the way a situation is construed to decrease emotional impact. We sought to test the effectiveness of an intervention that used feedback on HRV data to prompt positive reappraisal during a stressful work task. Participants (N=122) completed two 20-minute trials of an inbox activity. In-between the first and the second trial participants were assigned to the waitlist control condition, a positive reappraisal via psycho-education condition, or a positive reappraisal via HRV feedback condition. Results revealed that using HRV data to frame a positive reappraisal message is more effective than using psycho-education (or no intervention)–especially for increasing positive mood and reducing arousal.
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Aims To integrate existing theoretical perspectives on change management, subjective fit and occupational stress to better understand the effects of change on employee adjustment. Background Although subjective fit with organizational goals and objectives has been shown to have positive effects on employee adjustment, its role in the organizational change–occupational stress context is not understood. This represents a caveat in research when considering the notion that those who feel that they fit with the organization's goals may be better equipped to reconcile and deal with change. Design A cross-sectional survey of nurses from public and non-profit sector hospitals was conducted. Method Data were collected from 252 public and non-profit sector nurses via online surveys. Data were collected from June–October in 2010. Structural equation modelling was used to test the direct and indirect effects among the focal variables. Results The results showed that public and non-profit nurses experience flexibility-limiting and flexibility-promoting change initiatives and that these are differentially related to the perception of administrative stressors and adjustment with these relationships directly and indirectly influenced by perceptions of subjective fit. Flexibility-limiting change initiatives led to lower levels of subjective fit, higher levels of administrative stressors and less favourable adjustment. On the other hand, flexibility-promoting change practices led to higher levels of subjective fit, lower levels of administrative stressors and ultimately better adjustment. Conclusion The results further the theoretical understanding of the role of subjective fit in organizational change and occupational stress theories.
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Occupational stress research has consistently demonstrated many negative effects of work stressors on employee adjustment (i.e., job-related attitudes and health). Considerable literature also describes potential moderators of this relationship. While research has revealed that different workplace identifications can have significant positive effects on employee adjustment, it has neglected to investigate their potential stress-buffering effects. Based on identity theories, it was predicted that stress-buffering effects of different types of identifications (distal versus proximal) would be revealed when the identification type and employee adjustment outcome type (distal versus proximal) were congruent. Predictions were tested with an employee sample from five human service nonprofit organizations (N = 337). Hierarchical multiple regression analyses revealed that main and moderated effects relating to identification supported the notion that occupational stress would be reduced when there was congruence of distal and proximal identifications and distal and proximal outcome types. However, stress-buffering effects were also found for high identifiers and low identifiers that were not in line with hypotheses posing questions for the definitions of distal and proximal identifications. Findings are discussed in terms of theoretical and practical implications.
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This paper presents an accurate and robust geometric and material nonlinear formulation to predict structural behaviour of unprotected steel members at elevated temperatures. A fire analysis including large displacement effects for frame structures is presented. This finite element formulation of beam-column elements is based on the plastic hinge approach to model the elasto-plastic strain-hardening material behaviour. The Newton-Raphson method allowing for the thermal-time dependent effect was employed for the solution of the non-linear governing equations for large deflection in thermal history. A combined incremental and total formulation for determining member resistance is employed in this nonlinear solution procedure for the efficient modeling of nonlinear effects. Degradation of material strength with increasing temperature is simulated by a set of temperature-stress-strain curves according to both ECCS and BS5950 Part 8, which implicitly allows for creep deformation. The effects of uniform or non-uniform temperature distribution over the section of the structural steel member are also considered. Several numerical and experimental verifications are presented.
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Fire incident in buildings is common, so the fire safety design of the framed structure is imperative, especially for the unprotected or partly protected bare steel frames. However, software for structural fire analysis is not widely available. As a result, the performance-based structural fire design is urged on the basis of using user-friendly and conventional nonlinear computer analysis programs so that engineers do not need to acquire new structural analysis software for structural fire analysis and design. The tool is desired to have the capacity of simulating the different fire scenarios and associated detrimental effects efficiently, which includes second-order P-D and P-d effects and material yielding. Also the nonlinear behaviour of large-scale structure becomes complicated when under fire, and thus its simulation relies on an efficient and effective numerical analysis to cope with intricate nonlinear effects due to fire. To this end, the present fire study utilizes a second order elastic/plastic analysis software NIDA to predict structural behaviour of bare steel framed structures at elevated temperatures. This fire study considers thermal expansion and material degradation due to heating. Degradation of material strength with increasing temperature is included by a set of temperature-stress-strain curves according to BS5950 Part 8 mainly, which implicitly allows for creep deformation. This finite element stiffness formulation of beam-column elements is derived from the fifth-order PEP element which facilitates the computer modeling by one member per element. The Newton-Raphson method is used in the nonlinear solution procedure in order to trace the nonlinear equilibrium path at specified elevated temperatures. Several numerical and experimental verifications of framed structures are presented and compared against solutions in literature. The proposed method permits engineers to adopt the performance-based structural fire analysis and design using typical second-order nonlinear structural analysis software.