4,769 research outputs found
Osteoarthritis: epidemiology
No full textOsteoarthritis (OA) is the most common joint disorder in the world. In Western populations it is one of the most frequent causes of pain, loss of function and disability in adults. Radiographic evidence of OA occurs in the majority of people by 65 years of age and in about 80% of those aged over 75 years. In the US it is second only to ischaemic heart disease as a cause of work disability in men over 50 years of age, and accounts for more hospitalizations than rheumatoid arthritis (RA) each year. Despite this public health impact, OA remains an enigmatic condition to the epidemiologist. In this chapter, we will review the definition and classification of OA, its prevalence, incidence, risk factors and natural histor
Lower extremity physical performance and hip bone mineral density in elderly black and white men and women: cross-sectional associations in the Health ABC
No full textBACKGROUND: Aging is characterized by declines in physical capacity and bone mineral density (BMD), both of which contribute to increased risk for fracture. However, it is unclear if these factors coexist or are independent in elderly people, and if a relationship does exist, whether it varies by sex and/or race. METHODS: Data are from 847 white women, 723 black women, 927 white men, and 544 black men aged 70-79 years participating in the Health Aging and Body Composition (ABC) Study, a cohort of well-functioning community-dwelling elders. BMD (g/cm(2)) of the hip (femoral neck and trochanter) was determined by dual X-ray absorptiometry. Physical capacity measures included knee extensor strength, repeated chair-stands, gait speed (6 m), walking endurance (400 m), and standing balance. RESULTS: In analyses of BMD as a continuous measure, BMD and physical performance were most consistently related at the trochanter in black women, even after adjusting for body size and several covariates including physical activity. For each performance measure, black women in the bottom quartile(s) had lower BMD than those in the top quartile(s). For the femoral neck, there was a significant association with performance tasks, except for the 400-m walk. In comparison, only chair-rise performance was related to BMD at the femoral neck, and knee extensor strength, chair-rise performance, and balance with the trochanter in white women. For white and black men, trends existed only for lower BMD in those with poorer knee extensor strength. CONCLUSIONS: In this cohort of well-functioning young-old seniors, physical capacity is only modestly related to BMD at the hip. The association was strongest in black women, who as a group exhibited the poorest functional capacity in the cohort. Our data show that, although both poorer physical performance and low BMD are risk factors for fracture, they remain largely independent in the well-functioning young-old, except in black women. This independence suggests that interventions to reduce fracture incidence should be targeted at improving both physical performance and bone density
Interactively using Semantic Web knowledge: Creating scalable abstractions with FacetOntology
No full textThe amount of knowledge accessible on the Semantic Web is growing, and there is a need for a scalable solution to facilitate exploring that data. Currently approaches to exploring Semantic Web data either focus on exploring resources individually, following links during exploration, and making little use of collated data, or take the approach of collating and aligning multiple sources into one store for one purpose, and hand-crafting a specific browsing interface onto it. We present an approach that provides a scalable browsing interface, which can browse knowledge from the Semantic Web at will. Our approach creates abstractions of knowledge, collated into facets, which are described using FacetOntology. FacetOntology facilitates describing facets from RDF data, suitable for use in creating datasets for faceted browsing
Growth Morphologies and Mechanisms of Non-Equilibrium Solidified MC Carbide
No full textGrowth morphologies and mechanisms of the carbide of group IVB and VB elements (MC carbide), a typical faceted crystal, were studied with an estimated cooling rate from 102 to 105 K/s. Results showed that although the growth morphologies of the MC carbide vary remarkably with solidification cooling rate, the solid/liquid interface is always atomically smooth, and the growth mechanisms are always lateral growth. The growth mechanism transition from lateral to continuous growth mode, which was predicted by the classic crystal growth theory, was not observed for the TiC type MC carbide within the estimated cooling rate range of 102?105 K/s
Ruth Klüger: la creatività per non “smarrirsi strada facendo”
No full textR. Klüger, a jewish viennese, a US citizen and a germanist, is the Author of two autobiographies “weiter leben”and “unterwegs versore”. Written in a style which alternates between essay and poetry, account and recollection, they are the occasion for the Author to establish a dialogue with the women having as a focus the exchange of experiences and reflections over the status of the feminine emancipation
Eutectic MC Carbide Growth Morphologies of a Laser Clad TiC/FeAl Composite Coating
No full textIn this paper, eutectic MC carbide growth morphology and its evolution with laser scanning speed were studied comprehensively of a laser clad MC carbide reinforced FeAl intermetallic matrix composite coating. As the laser scanning speed increased, the growth morphology of eutectic MC carbide was found to be needle-aligned annulation, butterfly-like and well-developed dendrite
Performance analysis of the MC-CDMA system in frequency selective slow Rayleigh fading channels, DS-CDMA or MC-CDMA?
No full textThis report describes the Bit Error Probability (BEP) performance of Multi-Carrier Code Division Multiple Access (MC-CDMA) system using the RAKE-receiver in frequency selective slow Rayleigh fading channels. The analysis has been carried out by a theoretical approach using the characteristic function method for quadratic form of Gaussian random variables and by computer simulation. The BEP performance of Direct Sequence Code Division Multiple Access (DS-CDMA) system under the same conditions is analysed and compared with the BEP performance of the MC-CDMA system.Electrical Engineering, Mathematics and Computer ScienceTelecommunicatie- en Verkeersbegeleidingssysteme
Dynamics of Network Formation Processes in the Co-Author Model
No full textThis article studies the dynamics in the formation processes of a mutual consent network in game theory setting: the Co-Author Model. In this article, a limited observation is applied and analytical results are derived. Then, 2 parameters are varied: the number of individuals in the network and the initial probability of the links in the network in its initial state. A simulation result shows a finding that is consistent with an analytical result for a state of equilibrium while it also shows different possible equilibria.Dynamics, Network, Game Theory, Model,Simulation, Equilibrium, Complexity
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