Search results for " return"

Portfolios with fuzzy returns: Selection strategies based on semi-infinite programming

2008

AbstractThis paper provides new models for portfolio selection in which the returns on securities are considered fuzzy numbers rather than random variables. The investor's problem is to find the portfolio that minimizes the risk of achieving a return that is not less than the return of a riskless asset. The corresponding optimal portfolio is derived using semi-infinite programming in a soft framework. The return on each asset and their membership functions are described using historical data. The investment risk is approximated by mean intervals which evaluate the downside risk for a given fuzzy portfolio. This approach is illustrated with a numerical example.

The end of the Messinian Salinity Crisis in the western Mediterranean: insights from the carbonate platforms of south-eastern Spain.

2010

International audience; How the Messinian Salinity Crisis (MSC) ended is still a matter of intense debate. The Terminal Carbonate Complex (TCC) is a late Messinian carbonate platform system that recorded western Mediterranean hydrological changes from the final stages of evaporite deposition till the advent of Lago-Mare fresh- to brackish water conditions at the very end of Messinian times. A multidisciplinary study has been carried out in three localities in south-eastern Spain to reconstruct the history of TCC platforms and elucidate their significance in the MSC. Overall, this study provides evidence that the TCC formed following a regional 4th order water level rise and fall concomitant…

Estimating Verdoorn law for Italian firms and regions

2011

In empirical regional economics, returns to scale are typically estimated at the regional level in search for evidence on alternative theories of growth and agglomeration. However, returns to scale may also have a firm-level dimension. In this paper, we exploit micro level data and estimate the dynamic Verdoorn law in a multilevel-setting, where returns to scale are obtained simultaneously for the micro and the regional level. Using Italian firm-level data and the NUTS-3 level of aggregation, we estimate the classic and augmented versions of Verdoorn law for the manufacturing sector, and the rest of the economy for comparison. Our results show that increasing returns to scale co-exist at bo…

Improvement in yield and fruit size and quality of the main Italian table olive cultivar 'Nocellara del Belice'

2014

Olive (Olea europaea L.) shows alternate bearing, with unreliable cropping patterns and inconsistent fruit size and quality every year. In many countries, thinning with naphthaleneacetic acid (NAA) is used to minimise alternate bearing behavior in olives. However, in Italy, growers are reluctant to employ this practice and no detailed knowledge is available for specific cultivars. We evaluated the effects of spraying NAA on various dates on the productive and vegetative characteristics of the main Italian table olive cultivar'Nocellara del Belice'. Trunk cross-sectional area, fruit set, fruit drop, fruit size, pit size, yield per tree, crop density and flesh to pit ratio were analysed. The …

Viaggi nell’immaginario: il turismo virtuale nel sito UNESCO di Tarragona

2023

Le nuove tecnologie hanno trasformato in modo radicale non solo la geografia come disciplina, ma anche le geografie del mondo. Il digitale ha assunto, infatti, un ruolo di mediazione sempre più pervasivo nella produzione dello spazio, come delle conoscenze e degli immaginari geografici. Le possibilità offerte dal virtuale, in particolare, offrono oggi un contributo decisivo nella comunicazione dei significati attribuiti ai luoghi e rispondono in modo sempre più efficace ai bisogni emergenti del settore turistico. Le esperienze di visita mediate dal digitale mirano a coinvolgere i sensi e risultano efficaci quando promuovono immersioni rigorosamente realistiche. Nel quadro di queste riflessi…

Elliptically Symmetric Distributions: A Review of Achieved Results and Open Issues

2005

The spherically and elliptically symmetrical distributions are used in different statistical areas for different purposes such as the description of multivariate data, in order to find alternatives to the normal distribution in multinormality tests and in the creation of statistical models in which the usual assumption of normality is not realistic. Some achieved results, open issues and some proposals for their use in applications, especially in the financial area, are here presented.

Computational aspects in 2D SBEM analysis with domain inelastic actions

2009

The Symmetric Boundary Element Method, applied to structures subjected to temperature and inelastic actions, shows singular domain integrals. In the present paper the strong singularity involved in the domain integrals of the stresses and tractions is removed, and by means of a limiting operation, this traction is evaluated on the boundary. First the weakly singular domain integral in the Somigliana Identity (S.I.) of the displacements is regularized and the singular integral is transformed into a boundary one using the Radial Integration Method; subsequently, using the differential operator applied to the displacement field, the S.I. of the tractions inside the body is obtained and through…

2019

Abstract This paper examines the labor-market returns to a new form of postsecondary vocational education: vocational master's degrees. We use individual fixed effects models on a matched sample of students and non-students from Finland to capture any time-invariant differences across individuals. We find that attendance in vocational master's programs leads to an earnings increase of more than seven percent five years after entry. The estimated effect remains positive even if selection on unobservables is twice as strong as selection on observables. Earnings gains are similar by gender and age, but they are marginally higher for those in the health sector than for those in the business or …

The Return-to-Entrepreneurship Puzzle

2013

The returns to entrepreneurship are monetary and non-monetary. We offer new evidence on these returns using a large sample of genetically identical male twins. Our within-twin analysis suggests that OLS estimates are downwards, and traditional first-differenced panel data estimates upwards biased. We find no differences in the earnings of men with either low or high education. Our within-twin analysis of non-monetary returns shows that entrepreneurs with low education work longer hours and have greater responsibilities, but also face a reduced risk of divorce and less monotonous work tasks. The same does not apply to highly educated entrepreneurs.

Sustainability of Public Pension Systems

2020

The aim of this chapter is to review the main instruments and indicators used to measure the sustainability of PAYG pension systems. It will distinguish between defined contribution and defined benefit systems, due to the various implications that each of them has. It will also be necessary to review the different types of sustainability instruments, for example, those based on cash criteria, financial criteria set by the economic cycle and actuarial criteria. For the actuarial criteria, we will review the criteria of the internal rate of return (IRR) and the actuarial balance. Subsequently, we will review which countries publish official pension system sustainability data and what kind of …