Search results for "multivariate"
showing 10 items of 1520 documents
Social determinants of therapy failure and multi drug resistance among people with tuberculosis: A review
2017
Background Social determinants influence health and the development of tuberculosis (TB). However, a paucity of data is available considering the relationship of social determinants influencing therapy failure and multi drug resistance (MDR). We conducted a review investigating the relationship of common social determinants on therapy failure and MDR in people with TB. Methods PubMed and SCOPUS were searched without language restrictions until February 02, 2016 for studies reporting the association between socioeconomic factors (income, education and alcohol abuse) and therapy failure or MDR-TB. The association between social determinants and outcomes was explored by pooling data with a ran…
The Role of Statins on Helicobacter pylori Eradication: Results from the European Registry on the Management of H. pylori (Hp-EuReg)
2021
Statins could increase the effectiveness of Helicobacter pylori eradication therapies due to their anti-inflammatory effect. The aim of this study was to analyze the impact of this therapeutic association in real life. This is a multicenter, prospective, non-interventional study aimed at evaluating the management of H. pylori by European gastroenterologists. Patients were registered in an e-CRF by AEG-REDCap from 2013 to 2020. The association between statin use and H. pylori eradication effectiveness was evaluated through multivariate analysis. Overall, 9988 and 705 patients received empirical and culture-guided treatment, respectively. Overall, statin use was associated with higher effecti…
Factors influencing hospital infection control policies in Italian hospitals
2003
A study was undertaken to determine the resources available in Italian hospitals for the control of nosocomial infections and the factors favouring a successful approach. During January-May 2000 a questionnaire about infection control was sent to the hospital health director of all Italian National Health System hospitals treating acute patients and with more than 3500 admissions in 1999. An active programme was defined as a hospital infection control committee (HICC) meeting at least four times in 1999, the presence of a doctor with infection control responsibilities, a nurse employed in infection control and at least one surveillance activity and one infection control guideline issued or …
THE ROLE OF SUNK COSTS IN THE DECISION TO INVEST IN R&D
2009
We present a dynamic empirical model of a firm's R&D decisions that is consistent with the existence of sunk R&D costs, taking into account that these costs may differ between small and large firms, and among different technological regimes. We estimate a multivariate dynamic discrete choice model using firm-level data of Spanish manufacturing for 1990–2000. Conditional on firm heterogeneity and serially correlated unobservable factors, we find that R&D history matters. This true state dependence allows inferring the existence of sunk R&D costs associated with performing R&D. Sunk R&D costs are found to be higher for large, high-tech firms.
Comparing Correlation Matrix Estimators Via Kullback-Leibler Divergence
2011
We use a self-averaging measure called Kullback-Leibler divergence to evaluate the performance of four different correlation estimators: Fourier, Pearson, Maximum Likelihood and Hayashi-Yoshida estimator. The study uses simulated transaction prices for a large number of stocks and different data generating mechanisms, including synchronous and non-synchronous transactions, homogeneous and heterogeneous inter-transaction time. Different distributions of stock returns, i.e. multivariate Normal and multivariate Student's t-distribution, are also considered. We show that Fourier and Pearson estimators are equivalent proxies of the `true' correlation matrix within all the settings under analysis…
Docking and multivariate methods to explore HIV-1 drug-resistance: a comparative analysis
2007
In this paper we describe a comparative analysis between multivariate and docking methods in the study of the drug resistance to the reverse transcriptase and the protease inhibitors. In our early papers we developed a simple but efficient method to evaluate the features of compounds that are less likely to trigger resistance or are effective against mutant HIV strains, using the multivariate statistical procedures PCA and DA. In the attempt to create a more solid background for the prediction of susceptibility or resistance, we carried out a comparative analysis between our previous multivariate approach and molecular docking study. The intent of this paper is not only to find further supp…
QSPR prediction of retention times of phenylurea herbicides by biological plastic evolution.
2012
A simple/sensitive high-performance liquid chromatographic method, with ultraviolet (UV) detection, was developed for phenylurea-herbicide analysis, which involves preconcentration using solid-phase extraction. Mobile phase was acetonitrile/water at flow-rate of 1 mL.min-1 with direct UV absorbance detection at 210 nm. Analyte separation studied on a C18 column was applied successfully to herbicide analysis in soft drink's brands and tap water. Good linearity/repeatability was observed for all pesticides. Retention times increase as: metoxuron < monuron < diuron < matazachlor < linuron. They are modelled by structure-property relations. The effect of different types of features is analyzed:…
Predictive Factors for Changes in Quality of Life after Steroid Treatment for Active Moderate-to-Severe Graves' Orbitopathy: A Prospective Trial.
2019
<b><i>Objectives:</i></b> To investigate the predictive factors for changes in the quality of life (GO-QoL) of patients with Graves’ orbitopathy (GO) prior to and after specific treatment. <b><i>Methods:</i></b> A prospective follow-up study was conducted at an academic tertiary referral orbital center with a joint thyroid-eye clinic on 100 consecutive patients with GO. Before and after the standard 12-week course of weekly intravenous methylprednisolone (cumulative dose 4.5 g), the GO-QoL questionnaire provided by the European Group on Graves’ Orbitopathy (EUGOGO) was completed. Endocrine and ophthalmic assessments were performed at each visi…
Study of the microstructure and efficiency of YSZ-SPS finely structured ceramic coatings
2018
Thanks to the using of liquid carrier, suspension plasma spray (SPS) enables the manufacture of finely structured coatings. As for conventional plasma spraying (APS), the microstructures of SPS coatings can be tailored by controlling the spray conditions. However, SPS is more complicated than APS due to its number of modifiable parameters.This thesis aims to provide a more fundamental understanding of the relationship between SPS process parameters and the properties of YSZ coatings by identifying generic models based on the use of mathematical statistical methods for the study of influence and sensitivity of the individual parameters.Systematic experiments were carried out to study the inf…
Predictive factors of difficulty in lower third molar extraction : a prospective cohort study
2017
Background Several publications have measured the difficulty of third molar removal, trying to establish the main risk factors, however several important preoperative and intraoperative variables are overlooked. Material and Methods A prospective cohort study comprising a total of 130 consecutive lower third molar extractions was performed. The outcome variables used to measure the difficulty of the extraction were operation time and a 100mm visual analogue scale filled by the surgeon at the end of the surgical procedure. The predictors were divided into 4 different groups (demographic, anatomic, radiographic and operative variables). A descriptive, bivariate and multivariate analysis of th…