GeD spline estimation of multivariate Archimedean copulas

A new multivariate Archimedean copula estimation method is proposed in a non-parametric setting. The method uses the so called Geometrically Designed splines (GeD splines), recently introduced by Kaishev et al. (2006 a,b) [10] and [11], to represent the cdf of a random variable Wµ, obtained through the probability integral transform of an Archimedean copula with parameter µ. Sufficient conditions for the GeD spline estimator to posses the properties of the underlying theoretical cdf, K(µ; t), of Wµ, are given. The latter conditions allow for defining a three-step estimation procedure for solving the resulting non-linear regression problem with linear inequality constraints. In the proposed procedure,finding the number and location of the knots and the coefficients of the unconstrained GeD spline estimator and solving the constraint least-squares optimisation problem, are separated. Thus, the resulting spline estimator ^K (^µ; t) is used to recover the generator and the related Archimedean copula by solving an ordinary differential equation. The proposed method is truly multivariate, it brings about numerical efficiency and as a result can be applied with large volumes of data and for dimensions d ¸ 2, as illustrated by the numerical examples presented

Fast, linked, and open – the future of taxonomic publishing for plants: launching the journal PhytoKeys

The paper describes the focus, scope and the rationale of PhytoKeys, a newly established, peer-reviewed, open-access journal in plant systematics. PhytoKeys is launched to respond to four main challenges of our time: (1) Appearance of electronic publications as amendments or even alternatives to paper publications; (2) Open Access (OA) as a new publishing model; (3) Linkage of electronic registers, indices and aggregators that summarize information on biological species through taxonomic names or their persistent identifiers (Globally Unique Identifiers or GUIDs; currently Life Science Identifiers or LSIDs); (4) Web 2.0 technologies that permit the semantic markup of, and semantic enhancements to, published biological texts. The journal will pursue cutting-edge technologies in publication and dissemination of biodiversity information while strictly following the requirements of the current International Code of Botanical Nomenclature (ICBN)

ONYCHOMYCOSES OF LOW EXTREMITIES IN PATIENTS WITH DIFFERENT DERMATOSES

Our study involved 305 patients with skin diseases hospitalized in the Department of Dermatology and Venereology, Medical University of Varna, for a 6-month period (April-September, 1998). In 40 (13,1 %) of them onychomycoses of toe nails (1-10) nails as an attendant disease were established. The group included patients aged 45 to 73 years; 22 males and 18 females. Diagnosis of dermatophyte nail invasion was proved by the isolation and identification of the fungi from the affected nails. Onychomycoses accompanied several skin diseases such as erysipelas - 9, psoriasis vulgaris - 8, chronic venous insufficiency of lower extremities - 5, skin diseases with autoimmune genesis and prolonged immunosupressive therapy - 5, and other -13. That gavs reason to consider onychomycoses as predisposition factors in some dermatoses but in patients with decreased immune defense as predisposition factors for the appearance of the disease