102,412 research outputs found
Systemic inflammation, body composition, and physical performance in old community-dwellers
Background Chronic inflammation, changes in body composition, and declining physical function are hallmarks of the ageing process. The aim of the present study was to provide a preliminary characterisation of the relationship among these age-related phenomena via multivariate modelling.
Methods Thirty-five old adults (OAs) and 17 young adults (YAs) were enrolled. The volume of skeletal muscle, subcutaneous adipose tissue (SAT), and intermuscular adipose tissue (IMAT) of the thigh was quantified by three-dimensional magnetic resonance imaging. Muscle strength was measured by knee extension strength testing. In OAs, physical performance was further assessed via the Short Physical Performance Battery (SPPB). Multi-block partial least squares-discriminant analysis (PLS-DA) was employed to explore the relationship among inflammatory profiles and functional and imaging parameters. Double cross-validation procedures were used to validate the predictive ability of the PLS-DA model.
Results The optimal complexity of the PLS-DA model was found to be two latent variables. The proportion of correct classification was 92.3% in calibration (94.1% in YAs and 91.4% in OAs), 84.6% in internal validation (95.3% in YAs and 78.5% in OAs), and 82.6% in external validation (94% in YAs and 76.9% in OAs). Relative to YAs, OAs were characterised by smaller muscle volume, greater IMAT volume, lower muscle strength, and higher levels of myeloperoxidase, P-selectin, soluble intercellular adhesion molecule 1, and vascular cell adhesion molecule 1. Compared with OAs with SPPB >8, those scoring 8 were characterised by smaller muscle volume, greater SAT volume, lower muscle strength, and higher levels of interleukin 1 beta, 6, 10, 12, 13, tumour necrosis factor alpha, and granulocyte-macrophage colony-stimulating factor.
Conclusions Multi-block PLS-DA identified distinct patterns of relationships among circulating cytokines and functional and imaging parameters in persons of different ages and varying levels of physical performance. The longitudinal implementation of such an innovative strategy could allow for the tracking of health status over time, the early detection of deviations in health trajectories, and the monitoring of response to treatments
Long gamma-ray bursts in the Swift era: the color indices of their optical afterglows
We present an analysis of optical afterglows (OAs) of long GRBs which were mostly discovered by NASA Swift. We used the method of the color indices that uses the commonly available multiband photometry. We show that for most OAs, in the observer frame, these colors, corrected for the reddening inside our Galaxy, display prominent clustering in some color-color diagrams
Dynamic option adjusted spread and the value of mortgage backed securities
We extend a reduced form model for pricing mortgage-backed securities (MBS) pass through and provide a novel hedging tool for investors in this market. To calculate the price of an MBS traders use what is known as option-adjusted spread (OAS). The resulting OAS value represents the required basis points adjustment to reference curve discounting rates needed to match an observed market price. The OAS suffers from some drawbacks. For example, it remains constant until the maturity of the bond (thirty years in mortgage-backed securities), and does not incorporate interest rate volatility. We suggest instead what we call dynamic option adjusted spread (DOAS). The latter allows investors in the mortgage market to account for both prepayment risk and changes of the slope of the yield curve
Automating SLA-Driven API Development with SLA4OAI
The OpenAPI Specification (OAS) is the de facto standard
to describe RESTful APIs from a functional perspective. OAS has been
a success due to its simple model and the wide ecosystem of tools supporting the SLA-Driven API development lifecycle. Unfortunately, the
current OAS scope ignores crucial information for an API such as its
Service Level Agreement (SLA). Therefore, in terms of description and
management of non-functional information, the disadvantages of not having a standard include the vendor lock-in and prevent the ecosystem to
grow and handle extra functional aspects.
In this paper, we present SLA4OAI, pioneering in extending OAS not
only allowing the specification of SLAs, but also supporting some stages
of the SLA-Driven API lifecycle with an open-source ecosystem. Finally,
we validate our proposal having modeled 5488 limitations in 148 plans
of 35 real-world APIs and show an initial interest from the industry with
600 and 1900 downloads and installs of the SLA Instrumentation Library
and the SLA Engine.Ministerio de Economía y Competitividad TIN2015-70560-RMinisterio de Ciencia, Innovación y Universidades RTI2018-101204-B-C21Ministerio de Educación, Cultura y Deporte FPU15/0298
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