Clustering measure-valued data with Wasserstein barycenters

In this work, learning schemes for measure-valued data are proposed, i.e. data that their structure can be more efficiently represented as probability measures instead of points on $\R^d$, employing the concept of probability barycenters as defined with respect to the Wasserstein metric. Such type of learning approaches are highly appreciated in many fields where the observational/experimental error is significant (e.g. astronomy, biology, remote sensing, etc.) or the data nature is more complex and the traditional learning algorithms are not applicable or effective to treat them (e.g. network data, interval data, high frequency records, matrix data, etc.). Under this perspective, each observation is identified by an appropriate probability measure and the proposed statistical learning schemes rely on discrimination criteria that utilize the geometric structure of the space of probability measures through core techniques from the optimal transport theory. The discussed approaches are implemented in two real world applications: (a) clustering eurozone countries according to their observed government bond yield curves and (b) classifying the areas of a satellite image to certain land uses categories which is a standard task in remote sensing. In both case studies the results are particularly interesting and meaningful while the accuracy obtained is high.Comment: 18 pages, 3 figure

Numerical computation of convex risk measures

Abstract In this work we consider the problem of numerical computation of convex risk measures, using a regularization scheme to account for undesirable ?uctuations in the available historical data, combined with techniques from the Calculus of Variations

Towards a Common European Space for Asylum

In this paper, we provide a critical overview of the current migration policies of the EU as framed by the recent amendments of the EU migration policies since 2015. We highlight that the construction of the migration policy is a constitutive element of the spatial process of reorganization of territorial policies through the combination and diffusion of state, regional and global. We show that the perception of permanent and static migration pressure, and countries’ specialization in migration are the basis for diffusion of asylum and migration policies to a number of different countries imposing similar migration systems and establishing a global governance of migration regime. The paper highlights a geographic and political change in migration and border management, through the patterns of EU Member States cooperation, and in particular their reluctance to establish a common asylum system based on solidarity and the focus on substituting the lack of a common asylum system by bilateral externalization agreements the main objective of which is the management of migration and border control rather than guaranteeing asylum and refugee policies

Pod Morphology, Primary and Secondary Metabolite Profiles in Non-grafted and Grafted Carob Germplasm Are Configured by Agro-Environmental Zone, Genotype, and Growing Season

Carob is a predominantly rainfed tree crop of high nutritive value and a long history of adaptation to the edaphoclimatic stress conditions of the Mediterranean. However, declining attention to the carob tree in recent decades has aggravated genetic erosion. The extant in situ germplasm varies both in terms of pod morphology and composition, reflecting the genetic and physiological divide chiefly among grafted and non-grafted material, and possibly the impact of variable agro-environments. Accordingly, the present study aimed to establish a systematic categorization of the genetic and phenotypic diversity encountered across carob germplasm identified in situ throughout Cyprus, a historical center of production and genetic diversity for the species. Linking pod morphology, primary and secondary metabolite profiles with genotyped source material originating in different agro-environments and crop seasons would provide a framework for interpreting (a) the interaction of these factors in configuring carob pod physicochemical constitution, and (b) the relative stability of phenotypic traits against environmental and seasonal variation. Microsatellite analysis discriminated 36 genotypes out of the 124 trees located in nine traditional agro-environmental zones and revealed low genetic diversity within the grafted germplasm. Two landraces were identified: “Tillyria,” which is widespread and predominant, and “Kountourka,” which is mainly localized to the northeastern peninsula of Karpasia. Morphological traits, such as seeds-to-pod weight ratio, pod width and thickness were principally under genetic control. Contrarily, compositional traits, particularly total phenolic content—including condensed tannins, in vitro antioxidant capacity and to a lesser extent gallic acid, organic acids and minerals were under agro-environmental control. Agro-environmental zone also modulated principally fructose and glucose; sucrose was modulated equally by genotype and agro-environment, while total sugars were under genetic control. Statistically significant differences between seasons were detected for all traits except for the seeds-to-pod weight ratio, pod length and width. Hierarchical cluster analysis corroborates that Cyprus may be divided into two major agro-environmental zones modulating the compositional properties of the carob pulp. The present study provides a comprehensive insight into the extant carob genetic resources of Cyprus and advances our understanding of how genetic, agro-environmental and seasonal factors interact in shaping carob pod morphology and composition

A randomized trial comparing intensified CNOP vs. CHOP in patients with aggressive non-Hodgkin's lymphoma

The standard CHOP regimen may cure 30-40% of patients with advanced aggressive non-Hodgkin’s lymphoma (ANHL). Mitoxantrone is an anthracenedione, which is active in NHL and its toxicity profile may be more favorable than doxorubicin with respect to alopecia, mucositis and cardiotoxicity. This study was designed to compare the effectiveness of an escalated dose of mitoxantrone with that of standard doxorubicin, used in the CHOP regimen in patients with ANHL. One hundred and forty three eligible patients with ANHL were randomized to receive 6 cycles of either CHOP (n = 71) or intensified CNOP (iCNOP) (n = 72); with mitoxantrone 20 mg/m(2), i.v., d.1 instead of doxorubicin. Complete responders (CR) were again randomized either to receive interferon-alpha (IFN-alpha) maintenance (3 MU t.i.w., s.c.) or not. The CR rate was 70 vs. 76% for iCNOP and CHOP (p = 0.45); and the overall response rate was 81 vs. 83%, respectively (p = 0.71). The 5-year failure free survival (FFS) was 48 and 50% in the iCNOP and CHOP arm, respectively (p = 0.45), and the 5-year overall survival (OS) was 61 vs. 64% (p = 0.56). IFN-alpha did not prolong relapse free survival (p = 0.91), iCNOP produced less alopecia (p = 0.001) but more febrile episodes (p = 0.04) than CHOP, while requiring more frequent G-CSF support (p = 0.01). Two cases of acute myelogenous leukemia (AML) were recorded, both in the iCNOP arm (p = 0.14). In conclusion, iCNOP was equally effective to CHOP in patients with ANHL, producing more leukopenia and febrile episodes, but less alopecia. The development of two cases of secondary AML in the iCNOP arm is of concern