Rita Sousa

Estimation of the Mean of a Sensitive Variable in the Presence of Auxiliary Information

Sousa et al. (2010) introduced a ratio estimator for the mean of a sensitive variable and showed that this estimator performs better than the ordinary mean estimator based on a randomized response technique (RRT). In this article, we introduce a regression estimator that performs better than the ratio estimator even for modest correlation between the primary and the auxiliary variables. The underlying assumption is that the primary variable is sensitive in nature but a non sensitive auxiliary variable exists that is positively correlated with the primary variable. Expressions for the Bias and MSE (Mean Square Error) are derived based on the first order of approximation. It is shown that the proposed regression estimator performs better than the ratio estimator and the ordinary RRT mean estimator (that does not utilize the auxiliary information). We also consider a generalized regression-cum-ratio estimator that has even smaller MSE. An extensive simulation study is presented to evaluate the performances of the proposed estimators in relation to other estimators in the study. The procedure is also applied to some financial data: purchase orders (a sensitive variable) and gross turnover (a non sensitive variable) in 2009 for a population of 5,336 companies in Portugal from a survey on Information and Communication Technologies (ICT) usage.

Ratio Estimation of the Mean of a Sensitive Variable in the Presence of Auxiliary Information

We propose a ratio estimator for the mean of sensitive variable utilizing information from a non-sensitive auxiliary variable. Expressions for the Bias and MSE of the proposed estimator (correct up to first and second order approximations) are derived. We show that the proposed estimator does better than the ordinary RRT mean estimator that does not utilize the auxiliary information. We also show that there is hardly any difference in the first order and second order approximations for MSE even for small sample sizes. We also generalize the proposed estimator to the case of transformed ratio estimators but these transformations do not result in any significant reduction in MSE. An extensive simulation study is presented to evaluate the performance of the proposed estimator. The procedure is also applied to some financial data (purchase orders (sensitive variable) and gross turn-over (non-sensitive variable)) in 2009 for 5090 companies in Portugal from a survey on Information and Communication Technologies (ICT) usage.

Exponential-Type Estimators of the Mean of a Sensitive Variable in the Presence of Nonsensitive Auxiliary Information

Recently, Koyuncu et al. (2013) proposed an exponential type estimator to improve the efficiency of mean estimator based on randomized response technique. In this article, we propose an improved exponential type estimator which is more efficient than the Koyuncu et al. (2013) estimator, which in turn was shown to be more efficient than the usual mean estimator, ratio estimator, regression estimator, and the Gupta et al. (2012) estimator. Under simple random sampling without replacement (SRSWOR) scheme, bias and mean square error expressions for the proposed estimator are obtained up to first order of approximation and comparisons are made with the Koyuncu et al. (2013) estimator. A simulation study is used to observe the performances of these two estimators. Theoretical findings are also supported by a numerical example with real data. We also show how to, extend the proposed estimator to the case when more than one auxiliary variable is available.

Improved Mean Estimation of a Sensitive Variable Using Auxiliary Information in Stratified Sampling

Abstract Sousa et al. (2010) and Gupta et al. (2012) have recently introduced ratio and regression estimators for the mean of a sensitive variable which perform better than the ordinary mean estimator based on a Randomized Response Technique (RRT). In the present study we extend these estimators to the stratified sampling setting. The performance of the proposed estimators is compared to the exiting estimators both theoretically and through a simulation study. We also apply the proposed estimators to some real data.

War, Taxes and Gold: The inheritance of the Real

The inheritance of the real (the currency of the Kingdom of Portugal, from 1435 to 1910) on national fiscal and monetary institutions is presented as a response to the challenge of foreign invasions and of their aftermath. The Portuguese crown had to preserve national sovereignty over borders defined in the XIII century in the face of external military threats from neighboring states. The social contract enforced by the crown until the early XX century relied on the ability to obtain increasingly expensive warfare. The pressure to raise revenue became a motive for fiscal change since medieval times, as war provided social legitimacy for tax reform or currency depreciation. Tax reform involved the creation of new taxes (the sisa and the décima) with a comprehensive base, well before they were acknowledged to be part of a modern fiscal system. New methods of taxation, including the incidence of the décima on interest income, profits and even wages in order to improve the efficiency of the fiscal system were also introduced and the immunities enjoyed by the nobility and by the church were reduced. In spite of those modern features, for most of the period state finance was primarily based on domain revenues, coming from monopolies established on trade and other colonial resources. One of them, gold, was also used as money and powerfully affected the link between war and taxes. In particular, the amount and continuity of gold inflows allowed taxation to fall and remain low throughout the 1700s. The high share of customs in tax revenues and the concentration of other taxes (like the excise) in Lisbon were other peculiar attributes of the system. The fiscal collapse of the early 1800s shows how sensitive to fluctuations in foreign trade both domainial revenues and customs duties were. The importance of domainial revenues may also explain why institutional reforms did not develop in XVIII century Portugal as early as might be expected. The crown was unable to extend the modern features of its financial system and to resort to higher levels of consolidated public debt, the only way to deal with extraordinary expenditures. Wealth-holders did not support the modernization of state finance through the creation of a bank responsible for managing public debt and issuing convertible paper money. Perhaps the government’s commitment to upholding property rights was not credible enough. The increase in military expenditures was followed by the fall in colonial commerce due to the loss of Brazil. Either one of the shocks would have been sufficient to bring about a large budget deficit. The resort to inconvertible monetary creation in 1797 was responsible for a period of raging inflation lasting until the 1820s. Moreover, it engendered problems in monetary circulation up to the 1850s. Money creation was only disciplined with the reform of the monetary system and the adhesion to the gold standard in 1854. Compared with the previous period of monetary and financial instability, the almost forty years that elapsed until the declaration of inconvertibility in 1891 allowed living standards to catch up with the European average. The resort to foreign public debt as a way to finance short-term public deficit was based on the assumption that in the long term the increase in tax revenues would balance the deficit. The constitutional agreement that pacified the country in 1852 and the globalisation in the capital markets associated with the heyday of the classical gold standard also enabled this experience of convergence. Outside the gold standard, Portugal endured renewed financial and political difficulties. In 1910, a revolution created a republic and a new inconvertible currency. If, for the monarchy, convertibility had been the rule rather than the exception, the pressure of war remained and so did the difficulties in tax administration. Indeed the resilience of the latter may be the only acknowledged inheritance of the real.

Beyond fractional anisotropy in amyotrophic lateral sclerosis: the value of mean, axial, and radial diffusivity and its correlation with electrophysiological conductivity changes

PurposeThis paper aims to analyze the contribution of mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) in the detection of microstructural abnormalities in amyotrophic lateral sclerosis (ALS) and to evaluate the degree of agreement between structural and functional changes through concomitant diffusion tensor imaging (DTI), transcranial magnetic stimulation (TMS), and clinical assessment.MethodsFourteen patients with ALS and 11 healthy, age- and gender-matched controls were included. All participants underwent magnetic resonance imaging including DTI. TMS was additionally performed in ALS patients. Differences in the distribution of DTI-derived measures were assessed using tract-based spatial statistical (TBSS) and volume of interest (VOI) analyses. Correlations between clinical, imaging, and neurophysiological findings were also assessed through TBSS.ResultsALS patients showed a significant increase in AD and MD involving the corticospinal tract (CST) and the pre-frontal white matter in the right posterior limb of the internal capsule (p < 0.05) when compared to the control group using TBSS, confirmed by VOI analyses. VOI analyses also showed increased AD in the corpus callosum (p < 0.05) in ALS patients. Fractional anisotropy (FA) in the right CST correlated significantly with upper motor neuron (UMN) score (r = − 0.79, p < 0.05), and right abductor digiti minimi central motor conduction time was highly correlated with RD in the left posterior internal capsule (r = − 0.81, p < 0.05). No other significant correlation was found.ConclusionMD, AD, and RD, besides FA, are able to further detect and characterize neurodegeneration in ALS. Furthermore, TMS and DTI appear to have a role as complementary diagnostic biomarkers of UMN dysfunction.

Synchronous brain and intravascular B‐cell lymphoma after remission of an adult hemophagocytic syndrome

Hemophagocytic lymphohistiocytosis (HLH) should be considered in the differential diagnosis of adult patients with white matter disease. Brain involvement can be life‐threatening and should prompt aggressive therapy. Even after HLH remission, the possibility of subsequent deterioration due to emergence of an aggressive intravascular lymphoma is highlighted here.

Translation, Cultural Adaptation and Validation of the Satisfaction with Amplification in Daily Life Scale for European Portuguese

INTRODUCTION The scale Satisfaction with Amplification in Daily Life uses a simple and easily administered questionnaire to evaluate the adaptation of individuals to their hearing aids. The objective of this study is to validate the scale for European Portuguese speakers, by means of translation and cultural adaptation of the questionnaire. The study includes an evaluation of reproducibility and a description of the results of the administration of the questionnaire to patients fitted with hearing aids. MATERIAL AND METHODS We invited 147 individuals fitted with hearing aids (uni- or bilateral) to participate in the study. Participants had used a hearing aid for at least six weeks and were patients of the Department of Otolaryngology at the Egas Moniz Hospital (Lisbon). The consent as well the guidelines for translation from and into the English language were obtained from the author of the scale, and the translation from and into, and cultural adaptation were carried out, along with an evaluation of reproducibility and internal consistency. RESULTS The participants were 54% male and 46% female, aged between 16 and 93 (66.09 ± 17.41 years). The results of the study showed an overall level of satisfaction of 5.4 among hearing aids users. The sub-scale satisfaction levels were: positive effects 5.88, service and cost 5.25, negative effects 4.24, and self-image 5.57. The Cronbach α score was 0.75 which indicates good internal consistency. Furthermore, the questionnaires overall and sub-scale average scores did not differ significantly from the results obtained under the American scale. The inter-examiner reproducibility was also good. DISCUSSION This study provides reliable results of the scale for the Portuguese of Portugal and adequate internal consistency, with significant age variability in the sample. CONCLUSION This adaptation of the Satisfaction with Amplification in Daily Life questionnaire for European Portuguese speakers should be considered a good tool for evaluation of the level of satisfaction of hearing aid users, and until now, is the only available scale for speakers of European Portuguese.

Cost and Burden of Non-Small Cell Lung Cancer's in Portugal.

Borges M1,2,3, Gouveia M4, Alarcão J1, Sousa R1, Teixeira E5, Barata F6, Laranjeira E1, Lopes F1, Parente B7, Pinheiro L1, Vaz-Carneiro A1, Costa J1,2 1 Center for Evidence Based Medicine, Faculty of Medicine, University of Lisbon, Lisbon, Portugal 2 Clinical Pharmacology Unit, Institute of Molecular Medicine, Lisbon, Portugal 3 Centro Hospitalar Lisboa Central, Lisbon Portugal 4 Católica Lisbon School of Business and Economics, Lisbon, Portugal 5 Centro Hospitalar Lisboa Norte, Lisbon, Portugal 6 Centro Hospitalar Universitário de Coimbra, Coimbra, Portugal 7 Hospital CUF Porto, Porto, Portugal

1047PNON-SMALL CELL LUNG CANCER'S BURDEN OF DISEASE IN PORTUGAL

ABSTRACT Aim: To estimate the Disability Adjusted Life-Years (DALY) associated with Non-Small Cell Lung Cancer (NSCLC) during 2012 in Portugal. Methods: DALY combines Years of Life Lost (YLL) due to premature mortality and Years Lost due to Disability (YLD). The YLL correspond to the number of deaths multiplied by the present valued socially weighted life expectancy at the age at which death occurs using a standardized life table. For the distribution of lung cancer mortality by age and gender the WHO European mortality database was used. To estimate the proportion of these deaths that is due to NSCLC we applied a ratio (85.7%) based on data from the Diagnosis-Related Groups database. To estimate YLD in a particular time period, the number of incident cases in that period is multiplied by the average duration of the disease on a scale ranging from 0 (perfect health) to 1 (death). NSCLC incidence was estimated from Portuguese National and Regional Cancer Registry. The average duration of the disease was derived from the survival curves published by the International Association for the Study of Lung Cancer. Disability weights were taken from the Disability Weights for Diseases in the Netherlands Study. Results: A total of 3,180 deaths in Portugal in 2012 were caused by NSCLC, which corresponds to 2.0% of the total deaths in Portugal. The DALYs resulting from premature deaths caused by NSCLC in 2012 totaled 25,071 representing 4.5% of years lost generated by all deaths in the country. For 2012 it is estimated that 3,236 life years were lost due to disability. The total disease burden attributable to NSCLC is thus estimated at 28,307 DALY. Conclusions: NSCLC is an important cause of disease burden in Portugal and should receive adequate attention from policy makers. Disclosure: M.F. Borges: The Faculty of Medicine, University of Lisbon received an unrestricted grant from Laboratorios Pfizer Lda. to conduct this study; M. Gouveia: The Faculty of Medicine, University of Lisbon received an unrestricted grant from Laboratorios Pfizer Lda. to conduct this study; J. Alarcao: The Faculty of Medicine, University of Lisbon received an unrestricted grant from Laboratorios Pfizer Lda. to conduct this study; R. Sousa: The Faculty of Medicine, University of Lisbon received an unrestricted grant from Laboratorios Pfizer Lda. to conduct this study; F. Barata: The Faculty of Medicine, University of Lisbon received an unrestricted grant from Laboratorios Pfizer Lda. to conduct this study; E. Laranjeira: The Faculty of Medicine, University of Lisbon received an unrestricted grant from Laboratorios Pfizer Lda. to conduct this study; F. Lopes: The Faculty of Medicine, University of Lisbon received an unrestricted grant from Laboratorios Pfizer Lda. to conduct this study; B. Parente: The Faculty of Medicine, University of Lisbon received an unrestricted grant from Laboratorios Pfizer Lda. to conduct this study; L. Pinheiro: The Faculty of Medicine, University of Lisbon received an unrestricted grant from Laboratorios Pfizer Lda. to conduct this study; M.E. Teixeira: The Faculty of Medicine, University of Lisbon received an unrestricted grant from Laboratorios Pfizer Lda. to conduct this study; A. Vaz-Carneiro: The Faculty of Medicine, University of Lisbon received an unrestricted grant from Laboratorios Pfizer Lda. to conduct this study; J. Costa: The Faculty of Medicine, University of Lisbon received an unrestricted grant from Laboratorios Pfizer Lda. to conduct this study.