497 research outputs found

    The Development and Application of Massively Parallel Solid Mechanics Codes

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    Computational physicists at Sandia National Laboratories have moved the Eulerian CTH code, and the arbitrary-Lagrangian-Eulerian ALEGRA code to distributed memory parallel computers. CTH is a three-dimensional solid mechanics code used for large-deformation, shock wave analysis. ALEGRA is a three-dimensional arbitrary Lagrangian-Eulerian solid-mechanics code used for coupled large-deformation, shock and structural mechanics problems. This paper discusses our experiences moving the codes to parallel computers, the algorithms we used and our experiences running the codes

    Recent Advances in Graph Partitioning

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    We survey recent trends in practical algorithms for balanced graph partitioning together with applications and future research directions

    The vicious layering of multi-level governance in Southern Europe: the case of elderly care in Italy and Spain

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    Aging and changes in family arrangements and female employment have brought about important policy developments in long-term care. Southern European countries have relied for long on family care and residual social care for the dependent elderly. Two paradigmatic cases, Italy and Spain, have shown two apparently different trends during the last 15 years: while in Italy reforms seem to have been persistently blocked, in Spain, an ambitious reform has fallen short of expectations. Based on data on services and institutional arrangements, the article shows that a complex and inconsistent allocation of responsibilities across government levels, a sort of 'vicious layering' of multi-level governance, may be playing a key role in this situation. The article discusses the dysfunctional effects of such arrangements, namely territorial inequalities, cost-shifting between government levels and towards users and misallocation of resources. We suggest that the development and reform of LTC in Southern European countries must address these problems if they want to avoid getting marooned by a complex network of vetoes and resource allocation problems

    Molecular complexity determines the number of olfactory notes and the pleasantness of smells

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    One major unresolved problem in olfaction research is to relate the percept to the molecular structure of stimuli. The present study examined this issue and showed for the first time a quantitative structure-odor relationship in which the more structurally complex a monomolecular odorant, the more numerous the olfactory notes it evokes. Low-complexity odorants were also rated as more aversive, reflecting the fact that low molecular complexity may serve as a warning cue for the olfactory system. Taken together, these findings suggest that molecular complexity provides a framework to explain the subjective experience of smells

    Exploring earned value management in the Spanish construction industry as a pathway to competitive advantage

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    [EN] As a well established discipline and profession, project management has its distinctive tools and techniques. One of them that has been considered the embodiment of the core principles of project management is the Earned Value Management (EVM). In managing construction projects, the EVM has been considered as a suitable tool and hence, has been implemented in various construction industry but absent in some others. Taking into account the dynamic environment where construction companies have to operate, particularly in turbulence environments as the direct result of recent global economic downturn, this paper explores the potential implementation of EVM in one of the construction industry, the Spanish construction industry. The outcomes confirm the needs for and feasibility of implementing EVM as a structured approach in the industry to reposition the Spanish construction industry with the long term view to increase its project management maturity level as a pathway to gaining competitive advantage.Universitat Politecnica de Valencia [grant number 19701344]Sutrisna, M.; Pellicer, E.; Torres-MachĂ­, C.; Picornell, M. (2018). Exploring earned value management in the Spanish construction industry as a pathway to competitive advantage. International Journal of Construction Management. 20(1):1-12. https://doi.org/10.1080/15623599.2018.1459155S112201Anbari, F. T. (2004). Earned value project management method and extensions. IEEE Engineering Management Review, 32(3), 97-97. doi:10.1109/emr.2004.25113Aram, J. D., & Walochik, K. (1996). Improvisation and the Spanish Manager. International Studies of Management & Organization, 26(4), 73-89. doi:10.1080/00208825.1996.11656695Brandon, D. M. (1998). Implementing Earned Value Easily and Effectively. Project Management Journal, 29(2), 11-18. doi:10.1177/875697289802900204Brown, A., & Adams, J. (2000). Measuring the effect of project management on construction outputs: a new approach. International Journal of Project Management, 18(5), 327-335. doi:10.1016/s0263-7863(99)00026-5Bryde, D. J. (2003). Modelling project management performance. International Journal of Quality & Reliability Management, 20(2), 229-254. doi:10.1108/02656710310456635Chen, H. L., Chen, W. T., & Lin, Y. L. (2016). Earned value project management: Improving the predictive power of planned value. International Journal of Project Management, 34(1), 22-29. doi:10.1016/j.ijproman.2015.09.008De la Cruz, M. P., del Caño, A., & de la Cruz, E. (2006). Downside Risks in Construction Projects Developed by the Civil Service: The Case of Spain. Journal of Construction Engineering and Management, 132(8), 844-852. doi:10.1061/(asce)0733-9364(2006)132:8(844)Din, S., Abd-Hamid, Z., & Bryde, D. J. (2011). ISO 9000 certification and construction project performance: The Malaysian experience. International Journal of Project Management, 29(8), 1044-1056. doi:10.1016/j.ijproman.2010.11.001Eldin, N. N. (1989). Measurement of Work Progress: Quantitative Technique. Journal of Construction Engineering and Management, 115(3), 462-474. doi:10.1061/(asce)0733-9364(1989)115:3(462)Gidado, K. I. (1996). Project complexity: The focal point of construction production planning. Construction Management and Economics, 14(3), 213-225. doi:10.1080/014461996373476Hastak, M., Halpin, D. W., & Vanegas, J. (1996). COMPASS—New Paradigm for Project Cost Control Strategy and Planning. Journal of Construction Engineering and Management, 122(3), 254-264. doi:10.1061/(asce)0733-9364(1996)122:3(254)D. Holt, G., & S. Goulding, J. (2014). Conceptualisation of ambiguous-mixed-methods within building and construction research. Journal of Engineering, Design and Technology, 12(2), 244-262. doi:10.1108/jedt-02-2013-0020Ibbs, C. W., & Kwak, Y. H. (2000). Assessing Project Management Maturity. Project Management Journal, 31(1), 32-43. doi:10.1177/875697280003100106Jugdev, K., & Thomas, J. (2002). 2002 Student Paper Award Winner: Project Management Maturity Models: The Silver Bullets of Competitive Advantage? Project Management Journal, 33(4), 4-14. doi:10.1177/875697280203300402Kim, E., Wells, W. G., & Duffey, M. R. (2003). A model for effective implementation of Earned Value Management methodology. International Journal of Project Management, 21(5), 375-382. doi:10.1016/s0263-7863(02)00049-2Kim, T., Kim, Y.-W., & Cho, H. (2016). Customer Earned Value: Performance Indicator from Flow and Value Generation View. Journal of Management in Engineering, 32(1), 04015017. doi:10.1061/(asce)me.1943-5479.0000377Laufer, A., & Tucker, R. L. (1987). Is construction project planning really doing its job? A critical examination of focus, role and process. Construction Management and Economics, 5(3), 243-266. doi:10.1080/01446198700000023Liberatore, M. J., Pollack-Johnson, B., & Smith, C. A. (2001). Project Management in Construction: Software Use and Research Directions. Journal of Construction Engineering and Management, 127(2), 101-107. doi:10.1061/(asce)0733-9364(2001)127:2(101)Mir, F. A., & Pinnington, A. H. (2014). Exploring the value of project management: Linking Project Management Performance and Project Success. International Journal of Project Management, 32(2), 202-217. doi:10.1016/j.ijproman.2013.05.012Navon, R., & Haskaya, I. (2006). Is detailed progress monitoring possible without designated manual data collection? Construction Management and Economics, 24(12), 1225-1229. doi:10.1080/01446190600999097Onwuegbuzie, A. J., & Leech, N. L. (2005). Taking the «Q» Out of Research: Teaching Research Methodology Courses Without the Divide Between Quantitative and Qualitative Paradigms. Quality & Quantity, 39(3), 267-295. doi:10.1007/s11135-004-1670-0Oviedo-Haito, R. J., JimĂ©nez, J., Cardoso, F. F., & Pellicer, E. (2014). Survival Factors for Subcontractors in Economic Downturns. Journal of Construction Engineering and Management, 140(3), 04013056. doi:10.1061/(asce)co.1943-7862.0000811Pellicer, E., Sanz, M. A., Esmaeili, B., & Molenaar, K. R. (2016). Exploration of Team Integration in Spanish Multifamily Residential Building Construction. Journal of Management in Engineering, 32(5), 05016012. doi:10.1061/(asce)me.1943-5479.0000438Potts, K., & Ankrah, N. (2008). Construction Cost Management. doi:10.4324/9780203933015Vanhoucke, M. (2012). Project Management with Dynamic Scheduling. doi:10.1007/978-3-642-25175-7Yazici, H. J. (2009). The Role of Project Management Maturity and Organizational Culture in Perceived Performance. Project Management Journal, 40(3), 14-33. doi:10.1002/pmj.20121Yu, A. G., Flett, P. D., & Bowers, J. A. (2005). Developing a value-centred proposal for assessing project success. International Journal of Project Management, 23(6), 428-436. doi:10.1016/j.ijproman.2005.01.00

    Augmentation of osteochondral repair with hyperbaric oxygenation: a rabbit study

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    <p>Abstract</p> <p>Background</p> <p>Current treatments for osteochondral injuries often result in suboptimal healing. We hypothesized that the combination of hyperbaric oxygen (HBO) and fibrin would be superior to either method alone in treating full-thickness osteochondral defects.</p> <p>Methods</p> <p>Osteochondral repair was evaluated in 4 treatment groups (control, fibrin, HBO, and HBO+fibrin groups) at 2-12 weeks after surgical injury. Forty adult male New Zealand white rabbits underwent arthrotomy and osteochondral surgery on both knees. Two osteochondral defects were created in each femoral condyle, one in a weight-bearing area and the other in a non-weight-bearing area. An exogenous fibrin clot was placed in each defect in the right knee. Left knee defects were left empty. Half of the rabbits then underwent hyperbaric oxygen therapy. The defects in the 4 treatment groups were then examined histologically at 2, 4, 6, 8, and 12 weeks after surgery.</p> <p>Results</p> <p>The HBO+fibrin group showed more rapid and more uniform repair than the control and fibrin only groups, but was not significantly different from the group receiving HBO alone. In the 2 HBO groups, organized repair and good integration with adjacent cartilage were seen at 8 weeks; complete regeneration was observed at 12 weeks.</p> <p>Conclusions</p> <p>HBO significantly accelerated the repair of osteochondral defects in this rabbit model; however, the addition of fibrin produced no further improvement.</p

    Evolutionary Origins of Genomic Repertoires in Bacteria

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    Explaining the diversity of gene repertoires has been a major problem in modern evolutionary biology. In eukaryotes, this diversity is believed to result mainly from gene duplication and loss, but in prokaryotes, lateral gene transfer (LGT) can also contribute substantially to genome contents. To determine the histories of gene inventories, we conducted an exhaustive analysis of gene phylogenies for all gene families in a widely sampled group, the γ-Proteobacteria. We show that, although these bacterial genomes display striking differences in gene repertoires, most gene families having representatives in several species have congruent histories. Other than the few vast multigene families, gene duplication has contributed relatively little to the contents of these genomes; instead, LGT, over time, provides most of the diversity in genomic repertoires. Most such acquired genes are lost, but the majority of those that persist in genomes are transmitted strictly vertically. Although our analyses are limited to the γ-Proteobacteria, these results resolve a long-standing paradox—i.e., the ability to make robust phylogenetic inferences in light of substantial LGT

    Effects of chronic inflammatory bowel diseases on left ventricular structure and function: a study protocol

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    BACKGROUND: Experimental evidences suggest an increased collagen deposition in inflammatory bowel diseases (IBD). In particular, large amounts of collagen type I, III and V have been described and correlated to the development of intestinal fibrotic lesions. No information has been available until now about the possible increased collagen deposition far from the main target organ. In the hypothesis that chronic inflammation and increased collagen metabolism are reflected also in the systemic circulation, we aimed this study to evaluate the effects on left ventricular wall structure by assessing splancnic and systemic collagen metabolism (procollagen III assay), deposition (ultrasonic tissue characterization), and cardiac function (echocardiography) in patients with different long standing history of IBD, before and after surgery. METHODS: Thirty patients affected by active IBD, 15 with Crohn and 15 with Ulcerative Colitis, submitted to surgery will be enrolled in the study in a double blind fashion. They will be studied before the surgical operation and 6, 12 months after surgery. A control group of 15 healthy age and gender-matched subjects will also be studied. At each interval blood samples will be collected in order to assess the collagen metabolism; a transthoracic echocardiogram will be recorded for the subsequent determination of cardiac function and collagen deposition. DISCUSSION: From this study protocol we expect additional information about the association between IBD and cardiovascular disorders; in particular to address the question if chronic inflammation, through the altered collagen metabolism, could affect left ventricular structure and function in a manner directly related to the estimated duration of the disease

    Long term in-vivo studies of a photo-oxidized bovine osteochondral transplant in sheep

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    BACKGROUND: Articular cartilage has limited capacity to repair. Defects greater than 3 mm heal with formation of inferior fibrous cartilage. Therefore, many attempts have been made to find the ideal graft for larger cartilage lesions. Different grafts, such as untreated or cryopreserved osteochondral transplants, have been used with variable success. METHODS: Photo-oxidized osteochondral grafts were implanted in both femoral condyles of one ovine knee. Untreated xenogeneic and autogeneic grafts served as controls. Three groups of 8 sheep each were formed and they were sacrificed 6, 12 or 18 months after surgery. RESULTS: The macroscopic evaluation of the condyle and graft showed a well-maintained cartilage surface in most grafts at all time points. However, the host cartilage matrix deteriorated considerably in all xenogeneic, most autogeneic and fewer of the photo-oxidized grafts at 12 and 18 months, respectively. The blue colour of the photo-oxidized grafts resulting from the process of photo-oxidation was visible in all grafts at 6 months, had diminished at 12 months and had completely disappeared at 18 months after surgery. Histologically a loss of matrix staining was almost never noticed in untreated xenografts, transiently at 6 months in photo-oxidized grafts and increased at 12 and 18 months. Fusion between graft and host cartilage could be seen in photo-oxidized grafts at 12 and 18 months, but was never seen in autografts and xenografts. CONCLUSIONS: The photo-oxidation of osteochondral grafts and its use as transplant appears to have a beneficial effect on cartilage and bone remodelling. Osteochondral grafts pre-treated with photo-oxidation may be considered for articular cartilage replacement and therefore may delay artificial joint replacements in human patients
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