Search results for "Random"
showing 10 items of 3931 documents
Asking Sensitive Questions
2013
This article is an empirical contribution to the evaluation of the randomized response technique (RRT), a prominent procedure to elicit more valid responses to sensitive questions in surveys. Based on individual validation data, we focus on two questions: First, does the RRT lead to higher prevalence estimates of sensitive behavior than direct questioning (DQ)? Second, are there differences in the effects of determinants of misreporting according to question mode? The data come from 552 face-to-face interviews with subjects who had been convicted by a court for minor criminal offences in a metropolitan area in Germany. For the first question, the answer is negative. For the second, it is po…
Using random networks to study the dynamics of respiratory syncytial virus (RSV) in the Spanish region of Valencia
2011
[EN] Seasonal fluctuations in the incidence of several respiratory infections are a feature of epidemiological surveys all around the world. This phenomenon is characteristic of influenza and respiratory syncytial virus pandemics. However, the explanation of the seasonal outbreaks of these diseases remains poorly understood. Many statistical studies have been carried out in order to provide a correlation of the outbreaks with climatic or social factors without achieving a definitive conclusion. Here we show that, in a random social network, self-sustained seasonal epidemics emerge as a process modulated by the infection probability and the immunity period after recovering from the infection…
Selection of Large Sub-Samples from the Continuous Sample of Working Lives Representative of the Benefits Provided by the Spanish Public Pension Syst…
2016
The Continuous Sample of Working Lives (CSWL) is a set of anonymized microdata with information about individuals taken from Spanish Social Security records. It provides very valuable information, which is used in many studies on labor economics and in the analysis of the Spanish public pension system. This article presents two major contributions: The first is an analysis of how representative CSWL is of the population of pensioners for the period 2005-2013. It is concluded that the CSWL does not follow the same distribution as the population with respect to some types of benefits, and that this happens in most waves. One of the reasons is that it is obtained by simple random sampling, so …
Comparing data mining and deterministic pedology to assess the frequency of WRB reference soil groups in the legend of small scale maps
2015
Abstract The assessment of class frequency in soil map legends is affected by uncertainty, especially at small scales where generalization is greater. The aim of this study was to test the hypothesis that data mining techniques provide better estimation of class frequency than traditional deterministic pedology in a national soil map. In the 1:5,000,000 map of Italian soil regions, the soil classes are the WRB reference soil groups (RSGs). Different data mining techniques, namely neural networks, random forests, boosted tree, classification and regression tree, and supported vector machine (SVM), were tested and the last one gave the best RSG predictions using selected auxiliary variables a…
AUTOFOCALIZZAZIONE VIA RANDOM QUASI-PHASE-MATCHING IN GUIDE D’ONDA DI TANTALATO di LITIO
2010
We observe self-localization of light beams via second harmonic generation in a quasi-phase-matched proton-exchanged Lithium Tantalate slab waveguide in the presence of a random component of the periodically-poled grating.
Critical micellisation density: a SAS structural study of the unimer–aggregate transition of block-copolymers in supercritical CO2
2000
In this paper we report a SANS investigation of micelle formation by fluorocarbon-hydrocarbon block copolymers in supercritical CO2 (scCO2) at 313K. A sharp unimer-micelle transition is obtained due to the tuning of the solvating ability of scCO2 by profiling pressure. At high pressure the copolymer is in a monomeric state with a random coil structure. By lowering the pressure aggregates are formed with the hydrocarbon segments forming the core and the fluorocarbon segments forming the corona of spherical aggregates. This aggregateunimer transition is driven by the gradual penetration of CO2 molecules toward the core of the aggregate and is critically related to the density of the solvent, …
Influence of Some Ionic Liquids Containing the Trifluoromethanesulfonate Anion on the Vapor–Liquid Equilibria of the Acetone + Methanol System
2011
Isobaric vapor–liquid equilibria (VLE) for the binary systems acetone + 1-butyl-3-ethylimidazolium trifluoromethanesulfonate ([beim][triflate]), methanol + [beim][triflate], acetone + 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate ([bmpyr][triflate]), and methanol + [bmpyr][triflate] as well as the VLE for the acetone + methanol + [beim][triflate] and acetone + methanol + [bmpyr][triflate] ternary systems have been obtained at 100 kPa using a recirculating still. The addition of both ionic liquids to the solvent mixtures produced an important salting-out effect, and the azeotrope tended to disappear for small amounts of ionic liquid. The experimental binary data sets were independe…
HCC therapies--lessons learned.
2014
The antiangiogenic multikinase inhibitor sorafenib was the first systemic agent to demonstrate a significant improvement in the overall survival of patients with advanced hepatocellular carcinoma (HCC), thereby introducing molecularly-targeted therapy in a therapeutic field of unmet needs. However, survival benefits for patients on sorafenib treatment are modest in clinical practice and advancing the field is far more challenging than initially anticipated. Molecular and clinical heterogeneity diminishes signals of potential activity in unselected populations, and underlying liver cirrhosis seals the fate of many novel targeted agents by causing relevant toxicity and mortality. The failure …
Field-practice study of sorafenib therapy for hepatocellular carcinoma: a prospective multicenter study in Italy
2011
A multicenter randomized controlled trial established sorafenib as a standard of care for patients with advanced hepatocellular carcinoma (HCC). Because the study was prematurely interrupted due to survival benefits in the sorafenib arm, we conducted an observational study to adequately assess risks and benefits of this regimen in field practice. Starting in 2008, all clinically compensated patients with advanced HCC and those with an intermediate HCC who were unfit or failed to respond to ablative therapies were consecutively evaluated in six liver centers in Italy, for tolerability as well as radiologic and survival response to 800-mg/d sorafenib therapy. Treatment was down-dosed or inter…
Outcomes of hepatocellular carcinoma patients treated with sorafenib: a meta-analysis of Phase III trials
2019
Aim: To benchmark overall survival (OS) and time to radiological progression (TTP) of patients enrolled in randomized controlled trials (RCTs) assessing sorafenib in advanced hepatocellular carcinoma using individual participant survival data, and to meta-analyze prognostic factors for OS and TTP. Methods: RCTs were identified through literature search until December 2018. Individual participant survival was reconstructed with an algorithm from published Kaplan–Meier curves. Results: Ten RCTs were included. Median OS was 10.0 months (95% CI: 9.6–10.5), and median TTP was 4.1 months (95% CI: 3.8–4.3). Multivariable analyses showed HCV positivity, absence of macrovascular invasion and extra-…