Papers by Nicoletta Rosati
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Cemmap Working Papers, Nov 1, 2006
Inequality and poverty in Italy: theoretical models and empirical evidence
Inequality and Poverty in Italy: Theoretical Models and Empirical Evidence* Nicoletta Rosati^ Uni... more Inequality and Poverty in Italy: Theoretical Models and Empirical Evidence* Nicoletta Rosati^ University College London 12th February 2002 Abstract This ... Brandolini computes Gini index series from SFB and from SHIW in different ver-sions, according to different definitions of ...
Sex- and Maturity-Related Differences in Cortical Bone at the Distal Radius and Midshaft Tibia Evaluated by Quantitative Ultrasonography
Ultrasound in Medicine & Biology, 2016
Boys usually have higher values of bone mineral density measured by dual-energy X-ray absorptiome... more Boys usually have higher values of bone mineral density measured by dual-energy X-ray absorptiometry than girls, but contradictorily also have a greater incidence of fractures during growth. The purpose of this study was to investigate sex- and maturity-related differences in bone speed of sound (SoS) at the radius and tibia in a sample of 625 healthy children aged 10-14 y and to analyze the contributions of physical activity (PA) to possible dissimilarities. Radial and tibial SoS was evaluated by quantitative ultrasound, maturity was estimated as the years of distance from the peak height velocity age, and PA was assessed by accelerometry. Comparisons between sexes and maturity groups (low: below average [<-2.5 y], high: average or above [≥-2.5 y]) were made by two-sample t-tests with unequal variances. Girls in the high-maturity group had higher SoS at the radius and tibia compared with girls in the low-maturity group (p < 0.001). There were no SoS differences at the radius or tibia between the high- and low-maturity groups in boys. Within high-maturity children, girls had higher SoS than boys at the radius and tibia (p < 0.001). There were no differences at the radius and tibia between girls and boys with low maturity. The results were not modified after controlling for PA. Regardless of PA, the results provide insight into sex- and maturity-related differences in bone SoS at the distal radius and midshaft tibia from maturity less than 2.5 y from the peak height velocity age, with boys having lower SoS.
Economics Bulletin, Apr 5, 2009
The behaviour of the permanent and transitory economic shocks for different levels of household's... more The behaviour of the permanent and transitory economic shocks for different levels of household's welfare is studied using both consumption and income measures. After testing for heteroskedasticity of the economic shocks, we use local polynomial regression models to estimate the variance of the shocks conditional on welfare level. Italian data covering the period 1980-2004 show evidence of heteroskedasticity of both the transitory and the permanent economic shocks, with the poor experiencing higher variances. The permanent shocks seem to have a more uniform effect at all welfare levels.
Modelli con effetti individuali non osservabili: un limite per l'efficienza asintotica di stimatori ottenuti da indagini sezionali ripetute
The behaviour of the permanent and transitory economic shocks for different levels of households&... more The behaviour of the permanent and transitory economic shocks for different levels of households' welfare is studied using both consumption and income measures. After testing for heteroskedasticity of the economic shocks, we use local polynomial regression models to estimate the variance of the shocks conditional on welfare level. Italian data covering the period 1980-2004 show evidence of heteroskedasticity of both
Economics Bulletin, 2009
The behaviour of the permanent and transitory economic shocks for different levels of household's... more The behaviour of the permanent and transitory economic shocks for different levels of household's welfare is studied using both consumption and income measures. After testing for heteroskedasticity of the economic shocks, we use local polynomial regression models to estimate the variance of the shocks conditional on welfare level. Italian data covering the period 1980-2004 show evidence of heteroskedasticity of both the transitory and the permanent economic shocks, with the poor experiencing higher variances. The permanent shocks seem to have a more uniform effect at all welfare levels.
Statistics & Probability Letters, 2013
Comparing repeated-cross-section (RCS) and panel estimators, asymptotically there is no efficienc... more Comparing repeated-cross-section (RCS) and panel estimators, asymptotically there is no efficiency loss using synthetic individuals. Small-sample simulations show higher efficiency of panels for static models, but RCS estimators are superior in the dynamic case, especially for larger values of the auto-regressive parameter.
Research in Economics, 2003
This study investigates the pattern of inequality in Italy in the 1980s and the 1990s, by means o... more This study investigates the pattern of inequality in Italy in the 1980s and the 1990s, by means of both consumption and income measures, so as to separate its permanent and temporary components. The identification and estimation of the two components are based on a model introduced recently in the literature, which is adapted here to the case of biannual observations, due to the nature of the Italian data. We develop a Minimum Distance Estimator, and the procedure also allows us to test for the specification of the model.
Decision analysis and drug development portfolio management: uncovering the real options value of your projects
Expert Review of Pharmacoeconomics & Outcomes Research, 2002
Project selection and portfolio management are particularly challenging in the pharmaceutical ind... more Project selection and portfolio management are particularly challenging in the pharmaceutical industry due to the high risk - high stake nature of the drug development process. In the recent years, scholars and industry experts have agreed that traditional Net-Present-Value evaluation of the projects fails to capture the value of managerial flexibility, and encouraged adopting a real options approach to recover the missed value. In this paper, we take a closer look at the drug development process and at the indices currently used to rank projects. We discuss the economic value of information and of real options arising in drug development and present decision analysis as an ideal framework for the implementation of real options valuation.
Project Selection, Decision Analysis and Profitability in the Pharmaceutical Industry
The result of the ball possession in sport games is always a consequence of the mutual influence ... more The result of the ball possession in sport games is always a consequence of the mutual influence of both playing teams' performances. The present study aimed to evaluate whether the past offensive and defensive performance of handball teams affects the probability of scoring during the match and to examine how this influence varied in function of the match quality, measured by the sum of the rankings of playing teams. The data from 32273 observations of ball possessions were pooled from a panel database. This information was obtained from 224 matches from the 17th, 18th and 19th Men's World Handball Championships. It was assumed that matches were independent and each match produced data for two opposite teams. The data were used for the estimation of a linear probability model for the probability of scoring in handball match as a function of the past offensive performance of both teams and the point difference between teams in the last ball possession. The time-varying param...
American Journal of Hypertension, 1997
The plasma aldosterone-renin ratio (ARR), a useful screening rsst for primary hypersldosrsronism ... more The plasma aldosterone-renin ratio (ARR), a useful screening rsst for primary hypersldosrsronism (PHA), has besn tepnrted to bs al" fected by several anbhypertenmve medications such as beta blockers. calcium channel anlagunists, ACE inhibitors, aud diuretics. Discontinuation or such medicaliuns has been recommended m order to obtain the mho, but this IS difflcull and dangerous todoin the face of"severe hypenenston, We investigated the sensitivity of the ARR to amihypmensive agents in screening a series of W hypertensive patients followed by the intemd medicine, nephrology, and hypertension clinics at UWMC. Medications included behi bhxkers. calcium channel antagonists, diuretics, afphrr antagonists, and ACE inhibitors. Random plasma aldosferone crmccnfrahon (ngldl) and remn activity (ng%/3hr) were obtsined without discontinuation of medications. Serum creatmme and pxassium concentration were also measured, and any prior history of hypokalemia was determined. An ARlblfP3: I wnh serum aidowerone >20 ngldl was considered the threshold for Iurther workup of PHA, which included CT or MRf imaging and 1-131 norcholesterol adrenrd nuclear win to dmgnose adenoma or hyperplas]a, Workup completed on seventeen ptrents with an elevated ARR has diagnused eleven (12%) with adrenal adenomm confirmed by s.rgicaJ pathology and six (7%) with adrenal hyperplasia. These preliminary resul& suggest that the ARR is useful as a screening WI for PHA despite continuing a!mhyptnesive medlcauon, since the frequency of PHA ]dentlfled in our fwpulahon IS simdar tu that of previous observations. We also suggest that this may be a more common cause of hypertension than previously recognized. PHA may be more readily diagnosed if the ARR is used aã simple screening test without restriction of smtihypertensive medications,
Osteoporosis International, 2014
Physical activity (PA) have long been identified as a determining factor of the mineralization of... more Physical activity (PA) have long been identified as a determining factor of the mineralization of the skeleton, particularly in children. Our research supports the hypothesis that the geometry of the pelvis and proximal femur (PF) might moderate the effect of PA in the relative mineralization of the PF subregions. Introduction Using a longitudinal observational study with two evaluations and a 1-year follow-up interval, we investigated the influence of PA and skeletal geometry in bone mineral density (BMD) and bone mass distribution at the PF in 96 girls and 81 boys (10-12 years). It is plausible that the geometry of the pelvis-PF structure moderates mechanical forces exerted at the hip and therefore creates different degrees of mineralization among PF subregions. Methods Whole body and left hip dual X-ray absorptiometry scans were used to derive geometric measures of the pelvisinter-acetabular distance (IAD) and PF abductor lever arm (ALA). BMD was measured at the integral, superolateral (SL), and inferomedial (IM) femoral neck (FN), and at the trochanter (TR). These subregions were used to represent bone mass distribution via three BMD ratios: FN/PF, IM/SL, and TR/PF. PA was measured using accelerometry and a bonespecific PA questionnaire (BPAQ). Results A longitudinal data approach revealed BPAQ as a positive predictor for all BMD variables (p<0.05) except TR BMD in girls and FN BMD in boys. Comparing the most active with the less-active participants, the greatest benefits of PA were observed at the FN of the girls with the lowest IAD (p<0.001), at the FN of the boys with the highest IAD (p<0.001) and at the TR of the boys with the lowest ALA (p<0.01). Conclusions Geometric measures of IAD and ALA seem to moderate the effect of PA role in the relative mineralization of the PF regions. On the other hand, absolute BMD levels appear to be determined by mechanical loading.
Clinical Endocrinology, 1998
OBJECTIVE Primary aldosteronism (PA) is the most common endocrine cause of curable hypertension, ... more OBJECTIVE Primary aldosteronism (PA) is the most common endocrine cause of curable hypertension, but no single test unequivocally identifies it. Accordingly, we investigated the usefulness of a logistic multivariate discriminant analysis (MDA) approach for PA screening. DESIGN Generation of a logistic MDA function based on retrospective analysis of biochemical tests in a large cohort of referred patients with/without confirmed Conn's adenoma (CA), followed by prospective validation of the model. PATIENTS We investigated 574 selected hypertensives: 206 (32 with and 174 without CA) retrospectively, 48 (with a 13% prevalence of CA) prospectively for the validation of the model, and 320 referred hypertensives (with a 3.4% prevalence of CA) similarly evaluated. Patients were referred to a specialised centre for hypertension (4th Clinica Medica-University of Padua) and to a department of Internal Medicine of a regional hospital (Reggio Emilia). MEASUREMENTS In all patients we measured several demographic and biochemical variables and performed a captopril test. A stepwise analysis of variance, based on a model fitted with several different variables, identified baseline (sALDO) and captopril-suppressed plasma aldosterone (cALDO), supine plasma renin activity (sPRA) and K þ as the most informative. Therefore, two models of logistic MDA with sPRA, K þ , and either sALDO (model A) or cALDO (model B) were developed and used. ROC analysis was also performed to assess the optimal cut-off values. RESULTS The model B of MDA provided the best performance and identified CA with 100% sensitivity and 81% accuracy. When used prospectively it showed 100% sensitivity, both in the Padua (88% accuracy) and in the Reggio Emilia series (90% accuracy). However, at both institutions most patients with idiopathic hyperaldosteronism (IHA) were also detected. CONCLUSIONS Thus, although developed from patients with confirmed Conn's adenoma, a strategy based on multivariate discriminant analysis can be used prospectively for accurate screening for primary aldosteronism. Furthermore, it was proven to be accurate and applicable to patients tested with similar modalities at a different institution. Although this approach did not provide a clear-cut discrimination of Conn's adenoma from idiopathic hyperaldosteronism, it may avoid unnecessary and costly further testing in patients with a low probability of primary aldosteronism.
Journal of Applied Statistics, 2009
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Papers by Nicoletta Rosati