Search results for "Olio"
showing 10 items of 630 documents
TiO2 Impregnato con Poliossometallato Utilizzato come Fotocatalizzatore nella Degradazione di 2-Propanolo in Fase Vapore
2008
Aika-, ikä- ja kohorttivaikutukset kotitalouksien rahoitusvarallisuuden rakenteisiin Suomessa vuosina 1994-2004
2007
Typification of the names Anethum pusillum and Meum segetum (Apiaceae)
2022
Recent works (Jimenez-Mejias & Vargas 2015, Frankiewicz et al. 2021) have improved our knowledge about systematics and phylogeny of the Apiaceae: in detail, the Authors suggested the opportunity to merge several genera within Anethum Linnaeus (1753: 263), namely: Foeniculum Miller (1754: [513]), Ridolfia Moris (1841: 43), Pseudoridolfia Reduron, Mathez & S. R. Downie in Reduron et al. (2009: 496), and Schoenoselinum Jimenez-Mejias & Vargas (2015: 75). In this framework, we think that it is important to typify the names Anethum pusillum All. (Allioni 1773: 28) and Meum segetum Guss. (Gussone 1827: 346), both belonging to this “Anethum alliance” (as defined by Jimenez-Mejias &…
The Centaurea parlatoris complex (Asteraceae): taxonomic checklist and typifications
2021
A taxonomic account of the Centaurea parlatoris complex (Asteraceae), endemic to Sicily, is presented. This complex includes six taxa, three described in the 19th century (C. parlatoris, C. parlatoris var. tomentosa and C. parlatoris var. virescens) and three recently described (C. sicana, C. giardinae and C. heywoodiana). Starting from the designation of the types for the oldest plant names that have not been typified yet, taxonomic considerations are formulated and C. parlatoris var. virescens is elevated to the rank of species. An identification key and a distribution map complete this account.
Nomenclatural notes on Fabaceae described from Sicily
2021
A note about some taxa in Anthyllis and Trifolium (Fabaceae) described from Sicily is presented. Concerning Trifolium, we provide the lectotypification of the name T. pratense var. semipurpureum (≡ T. pratense subsp. semipurpureum), using a specimen preserved at PAL (Todaro’s collection). Concerning the Lojacono-Pojero’s name Vulneraria heterophylla var. parvula, it is lectotypified by a specimen at G. A neotype at NAP is proposed for the Gussone’s name Vulneraria heterophylla var. albiflora. As this latter name is applied to a taxon accepted here at specific rank, a new combination is validated. On the contrary, A. heterophylla var. parvula is considered as a new heterotypic synonym of Ant…
Revised lectotypification of the name Calendula maritima (Asteraceae)
2012
Troia, Angelo, Greuter, Werner, Raimondo, Francesco Maria (2012): Revised lectotypification of the name Calendula maritima (Asteraceae). Phytotaxa 71 (1): 48-51, DOI: 10.11646/phytotaxa.71.1.9, URL: http://biotaxa.org/Phytotaxa/article/view/phytotaxa.71.1.9
The Role of Covariance Matrix Forecasting Method in the Performance of Minimum-Variance Portfolios
2014
Providing a more accurate covariance matrix forecast can substantially improve the performance of optimized portfolios. Using out-of-sample tests, in this paper, we evaluate alternative covariance matrix forecasting methods by looking at (1) their forecast accuracy, (2) their ability to track the volatility of the minimum-variance portfolio, and (3) their ability to keep the volatility of the minimum-variance portfolio at a target level. We find large differences between the methods. Our results suggest that shrinkage of the sample covariance matrix improves neither the forecast accuracy nor the performance of minimum-variance portfolios. In contrast, switching from the sample covariance ma…
Volatility Weighting over Time in the Presence of Transaction Costs
2019
Numerous empirical studies demonstrate the superiority of dynamic strategies with a volatility-weighting-over-time mechanism. These strategies control the portfolio risk over time by adjusting the risk exposure according to updated volatility forecasts. Yet, to reap all the benefits promised by volatility weighting over time, the composition of the active portfolio must be revised rather frequently. Transaction costs represent a serious obstacle to benefiting from this dynamic risk control technique. In this article, we propose a modified volatility-weighting strategy that allows one to reduce dramatically the amount of trading costs. The empirical evidence shows that the advantages of the …
The Best Hedging Strategy in the Presence of Transaction Costs
2009
Considerable theoretical work has been devoted to the problem of option pricing and hedging with transaction costs. A variety of methods have been suggested and are currently being used for dynamic hedging of options in the presence of transaction costs. However, very little was done on the subject of an empirical comparison of different methods for option hedging with transaction costs. In a few existing studies the different methods are compared by studying their empirical performances in hedging only a plain-vanilla short call option. The reader is tempted to assume that the ranking of the different methods for hedging any kind of option remains the same as that for a vanilla call. The …
Option Pricing and Hedging in the Presence of Transaction Costs and Nonlinear Partial Differential Equations
2008
In the presence of transaction costs the perfect option replication is impossible which invalidates the celebrated Black and Scholes (1973) model. In this chapter we consider some approaches to option pricing and hedging in the presence of transaction costs. The distinguishing feature of all these approaches is that the solution for the option price and hedging strategy is given by a nonlinear partial differential equation (PDE). We start with a review of the Leland (1985) approach which yields a nonlinear parabolic PDE for the option price, one of the first such in finance. Since the Leland's approach to option pricing has been criticized on different grounds, we present a justification of…