Search results for "TF"

Sociālās platformas sporta spēļu organizēšanai izveide

2016

Maģistra darba autors Ēriks Timrots ir izvēlējies darba tēmu „Sociālās platformas sporta spēļu organizēšanai izveide”, atsaucoties uz sabiedrībā pieaugušo interesi pēc aktīva dzīvesveida piekopšanas. Maģistra darba mērķis, izmantojot teorētiskās zināšanas datorikas zinātnē un empīriskā pētījuma rezultātus, ir noskaidrot, kādu tehnoloģiju un pieeju izmantošana palīdzēs izstrādāt tīmekļa vietni un mobilo lietotni sporta spēļu organizēšanai. Pētījuma gaitā autors analizē divas pieejas, kā veidot mobilās lietotnes, apskata PHP ietvarus tīmekļa vietnes izstrādei, kā arī izveido sociālās platformas prototipu.

Imaging quality of multifocal intraocular lenses: automated assessment setup

2012

[EN] Purpose: A new technique for the assessment of the optical quality of multifocal intraocular lenses (MIOLs) under monochromatic and polychromatic illumination is presented. Methods: The system provides, in a totally automated procedure, the modulation transfer function (MTF) of the lens under test for different axial positions of the object. The artificial eye admits different artificial corneas, to optimise the axial resolution in the sampling of the MTF of the MIOL under test, and different pupils, to test the dependence of the optical performance of the MIOL on the eye pupil diameter. Results: The performance and sensitivity of the apparatus is tested with different commercial MIOLs…

Direct measurement of left ventricular outflow tract by transthoracic real-time 3D-echocardiography increases accuracy in assessment of aortic valve …

2007

Evaluation of aortic valve stenosis is a major clinical application of echocardiography. The widely employed continuity equation requires determination of the left ventricular outflow tract (LVOT) area. We aimed at testing whether direct area measurement in a volume data set is superior to conventional calculation from the LVOT diameter.We performed LVOT measurement in 20 normal subjects and 83 patients with moderate to severe aortic stenosis with a transthoracic real-time three-dimensional echocardiography (3D-TTE) technique in two systolic frames. The off-line 3D-evaluation allows full choice of section planes within the acquired volume data set. The aortic valve area was calculated from …

Mean‐Variance Portfolio Optimization

2010

Modulation of metallothionein and metal partitioning in liver and kidney of Solea senegalensis after long-term acclimation to two environmental tempe…

2014

9 pages, 3 figures, 5 tables

Risk forecasting models and optimal portfolio selection

2005

This study analyses, from an investor's perspective, the performance of several risk forecasting models in obtaining optimal portfolios. The plausibility of the homoscedastic hypothesis implied in the classical Markowitz model is dicussed and more general models which take into account assymetry and time varying risk are analysed. Specifically, it studies whether ARCH-type based models obtain portfolios whose risk-adjusted returns exceed those of the classical Markowitz model. The same analysis is performed with models based on the Lower Partial Moment (LPM) which take into account the assymetry in the distribution of returns. The results suggest that none of the models achieve a clearly su…

Identifying Portfolio-Based Risk Factors in Foreign Exchange Markets

2018

This paper shows that a link between the conditional mean and conditional volatility of any factor-mimicking portfolio in the foreign exchange (FX) market must exist if the proposed portfolio-based currency factor is priced and the pricing kernel has a linear factor structure. Thereby, this paper tests whether the carry risk factor and currency momentum are priced risk factors. Surprisingly, the carry risk factor does not meet the necessary conditions consistent with being a priced risk factor, whereas currency momentum indeed meets those criteria. The findings also indicate that the relation between the conditional mean and conditional risk is moreover economically reasonable for the curre…

Risk-Managed 52-Week High Industry Momentum, Momentum Crashes, and Hedging Macroeconomic Risk

2017

This is the first study that investigates the profitability of Barroso and Santa-Clara’s (2015) risk managing approach for George and Hwang’s (2004) 52-week high momentum strategy in an industrial portfolio setting. The findings indicate that risk-managing adds value as the Sharpe ratio increases, and the downside risk remarkably decreases. Even after controlling for the spread of the traditional 52-week high industry momentum strategy in association with standard risk-factors, the risk-managed version generates economically and statistically significant payoffs. Notably, the risk-managed strategy is partially explained by changes in cross-sectional return dispersion, whereas the traditiona…

Preparation of monolithic polymer-magnetite nanoparticle composites into poly(ethylene-co-tetrafluoroethylene) tubes for uses in micro-bore HPLC sepa…

2021

[EN] This paper describes the fabrication of a novel microbore monolithic column modified with magnetite nanoparticles (MNPs) prepared in a poly(ethylene-co-tetrafluoroethylene) (EFTE) tubing, and its application as stationary phase for the chromatographic separation of phosphorylated compounds. In order to obtain the composite column, a two-step procedure was performed. The formation of a glycidyl methacrylate-based monolith inside the activated ETFE tube was firstly carried out. Then, two incorporation approaches of MNPs in monoliths were investigated. The generic polymer was modified with 3-aminopropyltrimethoxysilane (APTMS) to be subsequently attached to MNP surfaces. Alternatively, AP…

Photografted fluoropolymers as novel chromatographic supports for polymeric monolithic stationary phases

2018

[EN] In this study, porous polymer monoliths were in situ synthesized in fluoropolymers tubing to prepare microbore HPLC columns. To ensure the formation of robust homogeneous polymer monoliths in these housing supports, the inner surface of fluoropolymer tubing was modified in a two-step photografting process. Raman spectroscopy and scanning electron microscopy (SEM) confirmed the successful modification of the inner poly(ethylene-co-tetrafluoroethylene) (ETFE) wall and the subsequent attachment of a monolith onto the wall. Poly(glycidyl methacrylate-co-divinylbenzene), poly(butyl methacrylate-co-ethyleneglycol dimethacrylate) and poly(styrene-co-divinylbenzene) monoliths were in situ synt…