663 resultados para 1367


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Objective The aim of this study was to demonstrate the potential of near-infrared (NIR) spectroscopy for categorizing cartilage degeneration induced in animal models. Method Three models of osteoarthritic degeneration were induced in laboratory rats via one of the following methods: (i) menisectomy (MSX); (ii) anterior cruciate ligament transaction (ACLT); and (iii) intra-articular injection of mono-ido-acetete (1 mg) (MIA), in the right knee joint, with 12 rats per model group. After 8 weeks, the animals were sacrificed and tibial knee joints were collected. A custom-made nearinfrared (NIR) probe of diameter 5 mm was placed on the cartilage surface and spectral data were acquired from each specimen in the wavenumber range 4 000 – 12 500 cm−1. Following spectral data acquisition, the specimens were fixed and Safranin–O staining was performed to assess disease severity based on the Mankin scoring system. Using multivariate statistical analysis based on principal component analysis and partial least squares regression, the spectral data were then related to the Mankinscores of the samples tested. Results Mild to severe degenerative cartilage changes were observed in the subject animals. The ACLT models showed mild cartilage degeneration, MSX models moderate, and MIA severe cartilage degenerative changes both morphologically and histologically. Our result demonstrate that NIR spectroscopic information is capable of separating the cartilage samples into different groups relative to the severity of degeneration, with NIR correlating significantly with their Mankinscore (R2 = 88.85%). Conclusion We conclude that NIR is a viable tool for evaluating articularcartilage health and physical properties such as change in thickness with degeneration.

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Business process management (BPM) is becoming the dominant management paradigm. Business process modelling is central to BPM, and the resultant business process model the core artefact guiding subsequent process change. Thus, model quality is at the centre, mediating between the modelling effort and related growing investment in ultimate process improvements. Nonetheless, though research interest in the properties that differentiate high quality process models is longstanding, there have been no past reports of a valid, operationalised, holistic measure of business process model quality. In attention to this gap, this paper reports validation of a Business Process Model Quality measurement model, conceptualised as a single-order, formative index. Such a measurement model has value as the dependent variable in rigorously researching the drivers of model quality; as antecedent of ultimate process improvements; and potentially as an economical comparator and diagnostic for practice.

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Whilst the debilitating fatigue experienced in patients suffering from Chronic Fatigue Syndrome (CFS) results in a subjective marked impairment in functioning, little research has investigated the impact of this disorder on quality of life. Forty-seven subjects with a confirmed diagnosis of CFS and 30 healthy controls were compared using the Sickness Impact Profile (SIP). A subgroup of subjects were interviewed regarding the impact CFS has had on their social and family relationships, work and recreational activities. Results from both the SIP and the interview revealed that CFS subjects had significantly impaired quality of life, especially in areas of social functioning. These findings highlight the importance of addressing the social isolation and loss of role functioning experienced by CFS sufferers.

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Purpose - Researchers debate whether tacit knowledge sharing through Information Technology (IT) is actually possible. However, with the advent of social web tools, it has been argued that most shortcomings of tacit knowledge sharing are likely to disappear. This paper has two purposes: firstly, to demonstrate the existing debates in the literature regarding tacit knowledge sharing using IT, and secondly, to identify key research gaps that lay the foundations for future research into tacit knowledge sharing using social web. Design/methodology/approach - This paper reviews current literature on IT-mediated tacit knowledge sharing and opens a discussion on tacit knowledge sharing through the use of social web. Findings - First, the existing schools of thoughts in regards to IT ability for tacit knowledge sharing are introduced. Next, difficulties of sharing tacit knowledge through the use of IT are discussed. Then, potentials and pitfalls of social web tools are presented. Finally, the paper concludes that whilst there are significant theoretical arguments supporting that the social web facilitates tacit knowledge sharing there is a lack of empirical evidence to support these arguments and further work is required. Research limitations/implications - The limitations of the review includes: covering only papers that were published in English, issues of access to full texts of some resources, possibility of missing some resources due to search strings used or limited coverage of databases searched. Originality/value - The paper contributes to the fast growing literature on the intersection of KM and IT particularly by focusing on tacit knowledge sharing in social media space. The paper highlights the need for further studies in this area by discussing the current situation in the literature and disclosing the emerging questions and gaps for future studies.

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The growing gap between engineering practice and engineering has been identified at the level of certain essential skills needed among practising engineers but not developed through the current education system. Coaching approach to learning and teaching has been proven to be an effective way to develop people in the workplace. A pilot coaching program is proposed to engineering students at Queensland University of Technology to enable holistic growth in order to better integrate them to the work force and society at large. The success measures and insights gained will be published on completion of the program. It is hoped that the outcomes of this study will better inform curriculum design and development in the engineering disciplines towards better transition between engineering education and engineering practice.

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This study reports the synthesis, characterization and application of nano zero-valent iron (nZVI). The nZVI was produced by a reduction method and compared with commercial available ZVI powder for Pb2+ removal from aqueous phase. Comparing with commercial ZVI, the laboratory made nZVI powder has a much higher specific surface area. XRD patterns have revealed zero valent iron phases in two ZVI materials. Different morphologies have been observed using SEM and TEM techniques. EDX spectrums revealed even distribution of Pb on surface after reaction. The XPS analysis has confirmed that immobilized lead was present in its zero-valent and bivalent forms. ‘Core-shell’ structure of prepared ZVI was revealed based on combination of XRD and XPS characterizations. In addition, comparing with Fluka ZVI, this lab made nZVI has much higher reactivity towards Pb2+ and within just 15 mins 99.9% removal can be reached. This synthesized nano ZVI material has shown great potential for heavy metal immobilization from waste water.

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Nobel laureates have achieved the highest recognition in academia, reaching the boundaries of human knowledge and understanding. Owing to past research, we have a good understanding of the career patterns behind their performance. Yet, we have only limited understanding of the factors driving their recognition with respect to major institutionalized scientific honours. We therefore look at the award life cycle achievements of the 1901–2000 Nobel laureates in physics, chemistry, and physiology or medicine. The results show that Nobelists with a theoretical orientation achieved more awards than laureates with an empirical orientation. Moreover, it seems their educational background shapes their future recognition. Researchers educated in Great Britain and the US tend to attract more awards than other Nobelists, although there are career pattern differences. Among those, laureates educated at Cambridge or Harvard are more successful in Chemistry, those from Columbia and Cambridge excel in Physics, while Columbia educated laureates dominate in Physiology or Medicine.

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Hydrogeophysics is a growing discipline that holds significant promise to help elucidate details of dynamic processes in the near surface, built on the ability of geophysical methods to measure properties from which hydrological and geochemical variables can be derived. For example, bulk electrical conductivity is governed by, amongst others, interstitial water content, fluid salinity, and temperature, and can be measured using a range of geophysical methods. In many cases, electrical resistivity tomography (ERT) is well suited to characterize these properties in multiple dimensions and to monitor dynamic processes, such as water infiltration and solute transport. In recent years, ERT has been used increasingly for ecosystem research in a wide range of settings; in particular to characterize vegetation-driven changes in root-zone and near-surface water dynamics. This increased popularity is due to operational factors (e.g., improved equipment, low site impact), data considerations (e.g., excellent repeatability), and the fact that ERT operates at scales significantly larger than traditional point sensors. Current limitations to a more widespread use of the approach include the high equipment costs, and the need for site-specific petrophysical relationships between properties of interest. In this presentation we will discuss recent equipment advances and theoretical and methodological aspects involved in the accurate estimation of soil moisture from ERT results. Examples will be presented from two studies in a temperate climate (Michigan, USA) and one from a humid tropical location (Tapajos, Brazil).

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Herpesviral haematopoietic necrosis is a disease of goldfish, Carassius auratus, caused by Cyprinid herpesvirus-2 (CyHV-2) infection. Quantitative PCR was carried out on tissue homogenates from healthy goldfish fingerlings, broodfish, eggs and fry directly sampled from commercial farms, from moribund fish submitted to our laboratory for disease diagnosis, and on naturally-infected CyHV-2 carriers subjected to experimental stress treatments. Healthy fish from 14 of 18 farms were positive with copy numbers ranging from tens to 10(7) copies mu g(-1) DNA extracted from infected fish. Of 118 pools of broodfish tested, 42 were positive. The CyHV-2 was detected in one lot of fry produced from disinfected eggs. Testing of moribund goldfish, in which we could not detect any other pathogens, produced 12 of 30 cases with 10(6)-10(8) copies of CyHV-2 mu g(-1) DNA extracted. Subjecting healthy CyHV-2 carriers to cold shock (22-10 degrees C) but not heat, ammonia or high pH, increased viral copy numbers from mean copy number (+/- SE) of 7.3 +/- 11 to 394 +/- 55 mu g(-1) DNA extracted after 24 h. CyHV-2 is widespread on commercial goldfish farms and outbreaks apparently occur when healthy carriers are subjected to a sharp temperature drop followed by holding at the permissive temperature for the disease.

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We present a detailed direct numerical simulation (DNS) of the two-dimensional Navier-Stokes equation with the incompressibility constraint and air-drag-induced Ekman friction; our DNS has been designed to investigate the combined effects of walls and such a friction on turbulence in forced thin films. We concentrate on the forward-cascade regime and show how to extract the isotropic parts of velocity and vorticity structure functions and hence the ratios of multiscaling exponents. We find that velocity structure functions display simple scaling, whereas their vorticity counterparts show multiscaling, and the probability distribution function of the Weiss parameter 3, which distinguishes between regions with centers and saddles, is in quantitative agreement with experiments.

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A parentheses-free code is suggested for the description of two-terminal electrical networks for computer analysis.

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Three polyester bag experiments were conducted with fistulated Bos indicus steers to determine the effect of the amount and type of nitrogen (N) supplement on the digestion rate of forages different in quality. In Experiment 1, test substrates were incubated in polyester bags in the rumen of steers fed ryegrass, pangola grass, speargrass and Mitchell grass hays in a 4 by 4 Latin-square design. In Experiment 2, test substrates were incubated in polyester bags in the rumen of steers fed speargrass hay supplemented with urea and ammonium sulfate (US), branched-chain amino acids with US (USAA), casein, cottonseed meal, yeast and Chlorella algae in a 7 by 3 incomplete Latin-square design. In Experiment 3, test substrates were incubated in polyester bags in the rumen of steers fed Mitchell grass hay supplemented with increasing amounts of US or Spirulina algae (Spirulina platensis). The test substrates used in all experiments were speargrass, Mitchell grass, pangola grass or ryegrass hays. Digestion rate of the ryegrass substrate was higher than that of the speargrass substrate (P < 0.05) in Experiment 1. Supplementation with various N sources increased the degradation rate and effective degradability of all incubated substrates above that apparent in Control steers (P < 0.05; Experiment 2). Supplementation of US and Spirulina increased degradation rate and effective degradability of ryegrass, pangola grass and Mitchell grass substrates above that apparent in Control steers (P < 0.05; Experiment 3). However, there was no further response on digestion rate of the substrates in increasing supplementation levels either for US or Spirulina. In conclusion, rate of digestion was affected by forage physical and anatomical properties. Supplementation with various N sources increased rate of digestion when the Control forage ration was very low in N but once a minimum level of N supplementation was reached, irrespective of form of N or other potential growth factors, there was no further increase in rate of digestion.

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To gain a better understanding of recent experiments on the turbulence-induced melting of a periodic array of vortices in a thin fluid film, we perform a direct numerical simulation of the two-dimensional Navier-Stokes equations forced such that, at low Reynolds numbers, the steady state of the film is a square lattice of vortices. We find that as we increase the Reynolds number, this lattice undergoes a series of nonequilibrium phase transitions, first to a crystal with a different reciprocal lattice and then to a sequence of crystals that oscillate in time. Initially, the temporal oscillations are periodic; this periodic behaviour becoming more and more complicated with increasing Reynolds number until the film enters a spatially disordered nonequilibrium statistical steady state that is turbulent. We study this sequence of transitions using fluid-dynamics measures, such as the Okubo-Weiss parameter that distinguishes between vortical and extensional regions in the flow, ideas from nonlinear dynamics, e.g. Poincare maps, and theoretical methods that have been developed to study the melting of an equilibrium crystal or the freezing of a liquid and that lead to a natural set of order parameters for the crystalline phases and spatial autocorrelation functions that characterize short- and long-range order in the turbulent and crystalline phases, respectively.