705 resultados para Fragility


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Lifecycle approaches have found their wide applications in analyzing, evaluating and assessing technologies and management methods in the infrastructure systems. While environmental problems such as global warming have become a serious issue in the world, researchers and practicing engineers in civil engineering have to pay attention to environmental impacts as well as function, safety, cost and aesthetics in the
whole lifecycle of civil infrastructures. In addition to the normal lifecycle activities accompanied with operation and aging, the effects of natural hazards such as earthquakes with a low occurrence probability but a high
hazard loss require a full consideration in determining both lifecycle cost and lifecycle environmental impact. In this research, an approach is proposed to predetermine the lifecycle environmental impact and costs of bridges from their construction and maintenance as well as the losses and recovery after natural hazards. Based on this research, it becomes possible to quantitatively outline the roles of bridge construction, maintenance and earthquake in both environmental impact and cost in the whole lifetime of a bridge, especially their constituent parts from seismic losses and recoveries.

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A portion of all herbicides applied to forests, croplands, road sides, and gardens are inevitably lost to water bodies either directly through runoff or indirectly by leaching through groundwater into ephemeral streams and lakes. Once in the aquatic environment, herbicides may cause stress within aquatic communities and radically alter community structure. Atrazine is one of the most effective and inexpensive herbicides in the world and is consequently used more frequently than any other herbicide. Atrazine is frequently detected in aquatic waters, and has been known to affect reproduction of aquatic flora and fauna, which in turn impacts on the community structure as a whole. This paper presents a summary of the reported direct and indirect impacts of atrazine on aquatic organisms and community structure. The information can be used for developing improved management guidelines and legislation. It is concluded that a single universal maximum limit on the atrazine application in catchments, as suggested by many regulatory authorities, does not provide adequate protection of the aquatic environment. Rather, it is advocated that flexible limits on the application of atrazine be developed in line with the potential risk of contamination to surface and subsurface water and fragility of the aquatic environment.

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These photographs on paper are about the fragility and sense of impermanence of the world. So it goes. Some are taken from a great distance around the spaces of cities, revisiting again and again the detritus of habitation or the shape and punctuation of nature or details of figures in close-up.

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This article identifies the fragility of relationships and ethical practices in the context of global commercial relationships and reflects upon the centrality of human relationships in commerce. The connections between people in global business are underpinned by ethical actions and outcomes and influenced by the degree that information and communication technology are part of the commercial relationship. Issues of trust, privacy, sharing, communication, security, anonymity, and learning emerge as relevant. This analysis positions relational ethics into the field of commerce, exposes the critical issues, and makes recommendations for ways to work with and further develop the link between commerce and relational ethics at the global level, especially in the light of developing technologies and the growth of e-commerce.

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The advent of the Internet and the World Wide Web has been instrumental in bringing about the growth in the implementation of web-based information systems (WBIS). Such systems are designed with the aim of improving productivity, data accuracy, and the reduction of paperwork and administrative overheads. Moreover, unlike their conventional non-web-based predecessors, the WBIS are commonly aimed at users who are casual and untrained, geographically distributed and non-homogenous. The dissemination of WBIS necessitates additional infrastructure support in the form of a security system, workflow and transaction management, and web administration. WBIS are commonly developed using an evolutionary approach, whereby the version of the application, acquired from the vendor, is first deployed as a pilot, in order to gather feedback from the target users before the evolutionary cycles commence. While a number of web development methodologies have been proposed by existing research, there is a dearth of empirical evidence that elucidates the experiences of project initiators in pursuing the evolution of web services, a process that undoubtedly involves dealing with stakeholder issues. This research project presents a phenomenological investigation of the experiences of project managers with the implementation of web-based employee service systems (ESS), a domain that has witnessed a sharp growth in Australia in recent times. However, the project managers’ rich, multidimensional account of their experiences with the implementation of ESS revealed the social obstacles and fragility of intra-organizational relationships that demanded a cautious and tactful approach. Thus, the study provides a socio-organizational perspective to web projects in contrast to the functionalist paradigm of current web development methodologies. The research also confirms that consideration of the concerns of stakeholders by project managers is crucial to the successive cycles of ESS evolution. Project managers address stakeholder concerns by pursuing actions that are aimed at encouraging ESS usage, but at the same time, such actions can have consequences necessitating subsequent iterations of system enhancement and improvement. Finally, the research also discovered that despite the different socio-political climate prevalent in various organizations, in which ESS are being implemented, the experiences of project managers in dealing with stakeholder concerns can be captured and independently confirmed in terms of their perceived relevance and usefulness in problem-solving within the application domain.

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Nhill is a short story that gently echoes a sense of anxiety. The very title  suggests emptiness and is a gentle exploration of a middle-class white couple's sense of not belonging to this landscape. Although they travel to the centre of the Little Dessert of western Victoria, it's 'heart of salt', everything in this gorgeous haze of a story of conspires to convey a sense of fragility and unreality.

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The Small Island Developing States (SIDS)1 in the Pacific, spread out over an area of 30 million square kilometres of ocean, and home to over 9 million people, face a complex and unique set of development challenges. As small, highly open economies they are particularly susceptible to external shocks, including fluctuations in import prices and export earnings in particular. Remoteness from major ports and export markets, low levels of connectivity with the outside world and susceptibility to natural hazards further complicate matters and have resulted in the Pacific islands being amongst the most vulnerable economies in the world. In spite of their increasing integration into global markets, most face further challenges owing to very limited absorptive capacities, limited resources, inadequate technology, lack of infrastructure and poor economic management and institutional capabilities. As a consequence, economic growth and related outcomes in most remain heavily reliant on external resources, typically including at least one of aid, migrant remittances, and foreign direct investment (FDI) (AusAID 2008 and McGillivray et al. 2008). The particular constraints and growth challenges of Pacific SIDS are too often overlooked in the development research literature. Moreover, the policy debate on how to promote and achieve growth in the Pacific islands can benefit from a deeper understanding of the nature and consequences of these often unique, combination of constraints. This Focus is devoted to development challenges facing these islands, specifically relating to the achievement of economic growth, and draws on five papers that were presented or tabled at the World Institute for Development Economics Research (WIDER) ‘Fragility and Development’ research project meeting held in Fiji in December 2006.

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Small Island Developing States (SIDS) are very different to other developing countries. Relative to GDP they have the highest levels of foreign trade and aid receipts of all developing countries. Remittances from abroad are a far more important source of income for SIDS, and some depend very heavily on export revenues. The quality of governance varies tremendously among SIDS, they are over-represented among countries classified as fragile states and many are prone to state failure. These and other factors combine to make SIDS highly vulnerable to external economic shocks. Achieving development in SIDS is as a consequence an especially complex task that requires an understanding of the roles played by aid, trade, remittances and governance in these countries. This paper looks at these issues, along with providing various stylised facts about SIDS. In so doing it serves as a background and broad contextual setting for the papers that follow in this Special Issue on 'Fragility and Development in Small Island Developing States'.

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Teaching sustainability ethics and creative practical technological applications holistically, in a multi-disciplinary ethos, with real community engagement is fraught with pedagogical and logistical issues. This paper reviews a highly community-acclaimed tertiary course/project, offered at the School of Architecture, Landscape Architecture & Urban Design at the University of Adelaide, undertaken on the Eyre Peninsula in 1st semester 2009. The course successfully enhanced student appreciation of rural community capacity building and economic fragility issues while undertaking a project-based approach to interrogating and working with rural communities to devise and demonstrate potential micro-relevant design and planning initiatives that could strengthen community resilience, climate change adaptiveness, and validate natural resource management aims within townships. The project involved some 120 students in 6 host communities through 6 local municipalities with the full support of the Natural Resource Management (NRM) Board and Local Government Association (LGA).

The paper reviews the project, its historical evolution, aims, objectives, learning strategies, community aspirations and outcomes, and positions such against various professional education accreditation frameworks. The methodological learning process, including its philosophical, pedagogical and instruments outcomes are reviewed and interrogated. The student learning outcomes, University reputation impact, and community impact, professional practice knowledge and skill attributes, and instrumental outcomes are also reviewed drawing upon evidence derived from extensive meetings, questionnaire surveys, synergistic NRM-sponsored research projects, student evaluation of teachings (SELTS), and local media coverage of the project.

The project has received applause from the Australian Institute of Architects (AIA) and Australian Institute of Landscape Architects (AILA), and preliminary endorsement from the Planning Institute of Australia (PIA), as being integral to the School’s curriculum that achieves their professional accreditation expectations of key learning experiences relevant to climate change, master planning and design, and community engagement. The project offers a possible educational model that enriches student experience and learning and addresses recent generic university community engagement policy expectations.

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Background
Exercise is widely recommended to reduce osteoporosis, falls and related fragility fractures, but its effect on whole bone strength has remained inconclusive. The primary purpose of this systematic review and meta-analysis was to evaluate the effects of long-term supervised exercise (≥6 months) on estimates of lower-extremity bone strength from childhood to older age.

Methods
We searched four databases (PubMed, Sport Discus, Physical Education Index, and Embase) up to October 2009 and included 10 randomised controlled trials (RCTs) that assessed the effects of exercise training on whole bone strength. We analysed the results by age groups (childhood, adolescence, and young and older adulthood) and compared the changes to habitually active or sedentary controls. To calculate standardized mean differences (SMD; effect size), we used the follow-up values of bone strength measures adjusted for baseline bone values. An inverse variance-weighted random-effects model was used to pool the results across studies.

Results

Our quality analysis revealed that exercise regimens were heterogeneous; some trials were short in duration and small in sample size, and the weekly training doses varied considerably between trials. We found a small and significant exercise effect among pre- and early pubertal boys [SMD, effect size, 0.17 (95% CI, 0.02-0.32)], but not among pubertal girls [-0.01 (-0.18 to 0.17)], adolescent boys [0.10 (-0.75 to 0.95)], adolescent girls [0.21 (-0.53 to 0.97)], premenopausal women [0.00 (-0.43 to 0.44)] or postmenopausal women [0.00 (-0.15 to 0.15)]. Evidence based on per-protocol analyses of individual trials in children and adolescents indicated that programmes incorporating regular weight-bearing exercise can result in 1% to8% improvements in bone strength at the loaded skeletal sites. In premenopausal women with high exercise compliance, improvements ranging from 0.5% to 2.5% have been reported.

Conclusions
The findings from our meta-analysis of RCTs indicate that exercise can significantly enhance bone strength at loaded sites in children but not in adults. Since few RCTs were conducted to investigate exercise effects on bone strength, there is still a need for further well-designed, long-term RCTs with adequate sample sizes to quantify the effects of exercise on whole bone strength and its structural determinants throughout life.

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Load-induced strains applied to bone can stimulate its development and adaptation. In order to quantify the incident strains within the skeleton, in vivo implementation of strain gauges on the surfaces of bone is typically used. However, in vivo strain measurements require invasive methodology that is challenging and limited to certain regions of superficial bones only such as the anterior surface of the tibia. Based on our previous study [Al Nazer et al. (2008) J Biomech. 41:1036–1043], an alternative numerical approach to analyse in vivo strains based on the flexible multibody simulation approach was proposed. The purpose of this study was to extend the idea of using the flexible multibody approach in the analysis of bone strains during physical activity through integrating the magnetic resonance imaging (MRI) technique within the framework. In order to investigate the reliability and validity of the proposed approach, a three-dimensional full body musculoskeletal model with a flexible tibia was used as a demonstration example. The model was used in a forward dynamics simulation in order to predict the tibial strains during walking on a level exercise. The flexible tibial model was developed using the actual geometry of human tibia, which was obtained from three-dimensional reconstruction of MRI. Motion capture data obtained from walking at constant velocity were used to drive the model during the inverse dynamics simulation in order to teach the muscles to reproduce the motion in the forward dynamics simulation. Based on the agreement between the literature-based in vivo strain measurements and the simulated strain results, it can be concluded that the flexible multibody approach enables reasonable predictions of bone strain in response to dynamic loading. The information obtained from the present approach can be useful in clinical applications including devising exercises to prevent bone fragility or to accelerate fracture healing.

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Objective: Cortical porosity, particularly at the endocortical region, is recognised to play a central role in the pathogenesis of bone fragility. Therefore, the purpose of this study was to: 1) demonstrate how cortical volumetric BMD (vBMD) distribution can be analysed from (p)QCT images and 2) highlight the clinical significance of assessing regional density distribution of cortical bone. 

Methods: We used pQCT to compare mid-tibial cortical volumetric BMD distribution of 20 young (age 24(SD2) years, mass 77(11) kg, height 178(6) cm) and 25 elderly (72(4) years, 75(9) kg, 172(5) cm) men. Radial and polar cortical vBMD distributions were analysed using a custom built open source analysis tool which allowed the cortex to be divided into three concentric cortical divisions and in 36 cortical sectors originating from the centroid of the bone.

Results:
Mean vBMD did not differ between the groups (1135(16) vs. 1130(28) mg/cm, P=0.696). In contrast, there was a significant age-group by radial division interaction for radial cortical vBMD (P<0.001).

Conclusions:
The proposed analysis method for analysing cortical bone density distribution of pQCT images was effective for detecting regional differences in cortical density between young and elderly men, which would have been missed by just looking at mean vBMD values.

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Summary This study aimed to describe treatment initiation rates for men who had recently sustained a fracture. Most (75.9%) men potentially eligible for subsidised treatment at the time of fracture remained untreated even after a subsequent fracture.

Introduction This study aimed to describe treatment initiation rates for men who had recently sustained a fracture.

Methods The study was conducted as part of the Geelong Osteoporosis Study in south-eastern Australia. Men in the study area who had sustained an incident fracture in the period July 2006 to December 2007 were identified from hospital radiology reports. A self-report questionnaire was sent to eligible participants approximately 12 months after fracture. Respondents were asked for details of medications prescribed for ‘osteoporosis/fracture/low bone mass’ before and after fracture, and where applicable, reasons for cessation of treatment.We analysed the results for 109 men aged 50 years and older who had sustained fracture in the study period.

Results Most (75.9%) men potentially eligible for subsidised treatment at the time of fracture remained untreated. Of the 87 men who were untreated, nine had osteoporosis at the hip and/or spine and 29 (26.6%) reported having sustained a low trauma prior fracture.

Conclusions Our findings are consistent with previously published data showing low rates of treatment initiation in men eligible for osteoporosis treatment. There appear to be barriers involving participants’ and medical practitioners’ knowledge, beliefs and attitudes regarding osteoporosis and treatment, as well as in the doctor–patient partnership in osteoporosis management. Establishment of clinical pathways for fracture management beyond orthopaedic care may be one of a range of appropriate responses.

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Background: There is evidence to suggest that β-blockers used in the management of cardiovascular disease may also modulate bone metabolism and reduce bone fragility.

Aim: The study aimed to determine the association between β-blocker use, serum markers of bone turnover and bone loss in early postmenopausal women.

Subjects and methods: In this observational study, we evaluated β-blocker exposure in association with serum levels of C-telopeptide and bone-specific alkaline phosphatase, and rates of bone loss. β-blocker use, concomitant therapy and lifestyle were documented for 197 women (50–59 years), 175 of whom had changes in whole body bone mineral density monitored over a 2–year period.

Results: Twenty-four β-blocker users were identified at baseline. After controlling for concomitant use of hormone therapy, C-telopeptide levels were 6.7% lower among β-blocker users (p = 0.02). No association was detected between bone-specific alkaline phosphatase and β-blocker use. Analysis of 15 β-blocker users and 152 non-users identified 2 years post-baseline showed that levels of C-telopeptide but not bone-specific alkaline phosphatase were predictors of adjusted rates of bone loss (p = 0.008 and p>0.05, respectively). Adjusted rates of bone loss were −0.001 ± 0.026 g cm−2 over 2 years for the users and −0.004 ± 0.025 g cm−2 over 2 years for non-users, but this difference was not significant.

Conclusion: β-blockers might suppress bone resorption with relative preservation of bone formation. A study with greater power is required to determine whether β-blocker use is associated with lower rates of bone loss.

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Introduction : Osteoporosis is associated with increased risk for fracture. However, most postmenopausal women have bone mineral density (BMD) within the normal or osteopenic range. The aim of this study was to determine the proportion of the population burden of fragility fractures arising from women at modest risk for fracture.

Methods : We measured baseline BMD in a population-based random sample of 616 postmenopausal women aged 60–94 years and followed these individuals for a median of 5.6 years (IQR 3.9–6.5) to determine the incidence of fractures according to age, BMD and the presence of a prior fracture.

Results : Based on WHO criteria, 37.6% of the women had normal total hip BMD, 48.0% had osteopenia and 14.5% had osteoporosis. The incidence of fracture during follow-up was highest in women with osteoporosis, but only 26.9% of all fractures arose from this group; 73.1% occurred in women without osteoporosis (56.5% in women with osteopenia, 16.6% in women with normal BMD). Decreasing BMD, increasing age and prior fracture contributed independently to increased fracture risk; in a multivariate model, the relative risk for fracture increased 65% for each SD decrease in BMD (RR=1.65, 95%CI 1.32–2.05), increased 3% for every year of age (RR=1.03, 95%CI 1.01–1.06) and doubled with prevalent fracture (RR=2.01, 95% CI 1.40–2.88). A prevalent fracture increased the risk for fractures such that women with osteopenia and prevalent fracture had the same, if not greater, risk as women with osteoporosis alone.