Search results for "Matrix"

Recent mathematical approaches to reconstruct phylogenies: A chemosystematist's and botanist's view

1989

Some basic problems of mathematical phylogenetics are discussed. While algorithms regularly depend on the principle of parsimony, some features of phylogenesis interfere with that principle. Nonrandomness of the distribution of mutations as well as the inconstancy of the molecular clock in time and within a given sequence can bias the calculated relationships of closely related taxa. True comparability of sequences is difficult to establish, since this requires defining of homology of positions and of functions of amino acids as well. Parallelism and convergence can give rise to errors in establishing homology. Furthermore, they are difficult to be integrated into a consistent mathematical …

Influence of scaffold pore size on collagen I development: A new in vitro evaluation perspective

2013

Bone tissue engineering takes part in the complex process of bone healing by combining cells, chemical/physical signals, and scaffolds with the scaffolds providing an artificial extracellular matrix network. The role of the support template for cell activity is crucial to guide the healing process. This in vitro study compared three different poly(D,L-lactic acid) scaffolds obtained by varying the pore size generated by applying different salt leaching processes. The influence of pore dimensions on the extracellular matrix produced by human osteosarcoma-derived osteoblasts (MG63 cell line) seeded on these different materials was analyzed. This study is targeted on the intermediate stage of…

Stability and l1-gain analysis for positive 2D T–S fuzzy state-delayed systems in the second FM model

2014

This paper considers the problems of delay-dependent stability and l"1-gain analysis for a class of positive two-dimensional (2D) Takagi-Sugeno (T-S) fuzzy linear systems with state delays described by the second FM model. Firstly, the co-positive type Lyapunov function method is applied to establish sufficient conditions of asymptotical stability for the addressed positive 2D T-S fuzzy system. Then, the l"1-gain performance analysis for the positive 2D T-S fuzzy delayed system is studied. All the obtained results are formulated in the form of linear matrix inequalities (LMIs) which are computationally tractable. Finally, an illustrative example is given to verify the effectiveness of the p…

Preparation of fluorinated polymer matrixes modified for biomedical applications

2011

Optimal manufacturing and mechanical characterization of high performance biocomposites reinforced by sisal fibers

2018

Abstract The increasing interest about eco-sustainable materials in the industrial production (automotive, civil construction, packaging), has led to the increase of the research works dealing with biocomposites. However, until now the most attention has been devoted to the development of short fiber biocomposites for non-structural applications, whereas only a few works have considered high performance biocomposites for structural applications. Consequently, the development of structural biocomposites from robust natural fibers, as sisal fibers, is a result expected from the scientific community, but not yet achieved. In order to give a contribution to the implementation of high performanc…

Evaluation of positron-emission-tomography for visualisation of migration processes in geomaterials

2008

Abstract Positron-emission-tomography (PET) was applied for direct visualisation of solute transport in order to overcome the limitations of conventional methods for measuring advection and diffusion properties. At intervals from minutes to days the 3D-spatial distribution of the PET-tracer is determined. This spatiotemporal evolution of the tracer concentration can be used as experimental basis for clarification of the relevant transport processes, derivation of transport parameters, and model calibration. Here, 18 F and 124 I in 0.01 M carrier solution of KF and KI, respectively, have been chosen out of the limited number of available PET-tracers, primarily on account of their decay time …

Oral plus vaginal alpha-lipoic acid in women at risk for preterm delivery

2018

Objective: The etiology of preterm labor is multifactorial. An inflammatory response is always involved with the activation of NF-kB that determines synthesis and release of inflammatory molecules, implicated in fetal membrane activation, cervical modifications, abdominal pain and spontaneous uterine contractions. There is a close relationship between preterm birth and cervical shortening in the second quarter of pregnancy. We evaluated the benefits of alpha-lipoic acid administration on women considered at risk of preterm delivery due to the presence of symptoms (pelvic pain and uterine contractions) or reduced cervical length. Patients and Methods: This prospective observational study was…

An Importance-Performance Matrix Analysis of the Factors Influencing US Tourists to Use Airbnb

2019

After 10 years of Airbnb and its significant growth, this research is conducted to identify which factors really matter to Airbnb users today. It provides an integrated approach, since it aggregates factors that other studies have considered separately. With a sample of 101 US respondents, the partial least squares structural equation modelling results evidence that the only factors that influence future intentions to use Airbnb are its unique and varied accommodations and satisfaction. Enjoyment was also found to have a positive effect on Satisfaction. The study further investigates these factors with an Importance Performance map, providing guidance for the prioritization of managerial ac…

New Innovation Identification Approach Development Matrix

2018

Innovations have become one of the contemporary economics key driving forces behind competitive advantages and have become socioeconomic category of their own. Diffusion of innovations, which is an integral part of the scientific and technological base of national economies, promotes structural changes in economy. Companies have to pay close attention to market trends and have to be able to identify and create new innovations, thus increasing their competitiveness and meeting consumer demands and expectations. The objective of this research is to evaluate the concept of different innovations in organizations and propose a complex approach to identifying innovations in the form of a matrix t…

CERTIFICATION CRITERIA MATRIX FOR EXPERT RATING OF PROFESSIONAL SERVICES

2018

In the Latvian certification system of individuals, there is necessary to ensure appropriate process realization in the interests of public protection and government needs, which gets incorporated into the EU common structure. An assessment of the certification system and its institutional structure is done with the aim to develop proposals for the improvement of the Latvian certification system for reducing costs, while ensuring both high system efficiency and recipients services and the public interest. To achieve its goals, the research study provided a summary of the situation in Latvia, as well as in the neighbouring countries: Lithuania, Poland, Estonia and Finland. During the researc…