CVaR minimization by the SRA algorithm

Using the risk measure CV aR in �nancial analysis has become more and more popular recently. In this paper we apply CV aR for portfolio optimization. The problem is formulated as a two-stage stochastic programming model, and the SRA algorithm, a recently developed heuristic algorithm, is applied for minimizing CV aR

Thickness-dependent magnetic structure of ultrathin Fe/Ir(001) films: from spin-spiral states towards ferromagnetic order

We present a detailed study of the ground-state magnetic structure of ultrathin Fe films on the surface of fcc Ir(001). We use the spin-cluster expansion technique in combination with the relativistic disordered local moment scheme to obtain parameters of spin models and then determine the favored magnetic structure of the system by means of a mean field approach and atomistic spin dynamics simulations. For the case of a single monolayer of Fe we find that layer relaxations very strongly influence the ground-state spin configurations, whereas Dzyaloshinskii-Moriya (DM) interactions and biquadratic couplings also have remarkable effects. To characterize the latter effect we introduce and analyze spin collinearity maps of the system. While for two monolayers of Fe we find a single-q spin spiral as ground state due to DM interactions, for the case of four monolayers the system shows a noncollinear spin structure with nonzero net magnetization. These findings are consistent with experimental measurements indicating ferromagnetic order in films of four monolayers and thicker.Comment: 9 pages, 7 figure

The impact of perceived corporate environmental performance on the behavior of capital market decision makers : analysis of food industry companies

Environmental protectionism and sustainable development has been gaining increased attention among governments, investors and consumers alike. As a result, firms are facing growing pressure from the various stakeholders to improve their environmental performance. This study is focusing on the food industry, which in recent years has been a subject of increased scrutiny due to their role in resource consumption, waste generation and unsustainable production practices. Our research is aiming to examine how the financial community evaluates the environmental stewardship of food industry companies as proxied by market reactions in response to environmental news. Are all company related environmental news items evaluated equally, and which financial and non-financial firm-specific attributes can influence market responses? Have there been changes in reactions on the stock exchange in the past two decades

Agrobacterium vitis strains lack tumorigenic ability on in vitro grown grapevine stem segments

Grapevine stem segments were cocultivated with three different Agrobacterium tumefaciens and three different A. vitis strains. A. tumefaciens strains induced tumors at variable frequencies, while A. vitis-infected stem segments never formed crown galls. The tumorous nature of tissues grown on hormone free medium was confirmed by opine assays. Bioinformatic and PCR analysis of the virulence regions of various A. tumefaciens and A. vitis Ti plasmids showed that virH2 and virK genes are common in A. tumefaciens but they are lacking from A. vitis. Thus virH2 and virK genes may be essential for grapevine stem segment transformation, but expression of certain T-DNA genes of A. vitis may also prevent the growth of transformed cells. Our data indicate that the tumorigenic ability of A. vitis is different on intact plant and on their explants, and that the specific host association of A. vitis on grapevine is probably determined by physiological and biochemical factors (e. g., better colonizing ability) rather than by its increased tumorigenic ability. Therefore it is not reasonable to develop „helper” plasmids for grapevine transformation from A. vitis pTis, unless their avirulence on in vitro explants is determined by T-DNA gene(s). Due to the inability of A. vitis to induce tumors on grapevine stem segments, the use of in vitro explant assays cannot be reliably used to select A. vitis resistant grapevine genotypes or transgenic lines

Role of oxygen vacancy defect states in the n-type conduction of β-Ga[sub 2]O[sub 3]

Based on semiempirical quantum-chemical calculations, the electronic band structure of β-Ga2O3 is presented and the formation and properties of oxygen vacancies are analyzed. The equilibrium geometries and formation energies of neutral and doubly ionized vacancies were calculated. Using the calculated donor level positions of the vacancies, the high temperature n-type conduction is explained. The vacancy concentration is obtained by fitting to the experimental resistivity and electron mobility

Conservation value of the native Hungarian wild grape (Vitis sylvestris Gmel.) evaluated by microsatellite markers

Wild grape (Vitis sylvestris GMEL.) has became a highly threatened species in Europe because of habitat loss, competition with alien grape species and intensive forest exploitation. Twenty-three Vitis spp. samples were analysed at 8 microsatellite loci to estimate the genetic diversity of the natural Vitis sylvestris specimens. In order to analyse the morphological traits and to perform molecular analysis, 11 native individuals were sampled from 6 remnant Hungarian habitats of the wild grape. To compare the genetic relationships among the wild specimens, samples from Turkish habitats, as well as cultivars of Vitis vinifera, Vitis labrusca and Vitis riparia were also included. Genetic diversity was higher within the Hungarian wild grape locations, with a mean of He = 0.74, which was higher that of samples originating from a larger area of Turkey, He = 0.69. Most of the Hungarian samples formed a well-defined, separate branch on the NJ tree. Based on the morphological traits and molecular analysis on the territory of Szentendre Island, formerly considered to be one of the largest native locations of wild grape, interspecific hybrids of Vitis sylvestris and Vitis riparia were identified. It can be concluded from the results that most of the Hungarian habitats studied could be valuable for the conservation. This paper reports on Hungarian Vitis sylvestris habitats, providing the first genetic study on diversity and on the relationship of Vitis sylvestris to other Vitis specimens, wild or cultivated, in the central part of the Carpathian Basin