A Generalized Gaussian Extension to the Rician Distribution for SAR Image Modeling

In this paper, we present a novel statistical model, $\textit{the generalized-Gaussian-Rician}$ (GG-Rician) distribution, for the characterization of synthetic aperture radar (SAR) images. Since accurate statistical models lead to better results in applications such as target tracking, classification, or despeckling, characterizing SAR images of various scenes including urban, sea surface, or agricultural, is essential. The proposed statistical model is based on the Rician distribution to model the amplitude of a complex SAR signal, the in-phase and quadrature components of which are assumed to be generalized-Gaussian distributed. The proposed amplitude GG-Rician model is further extended to cover the intensity SAR signals. In the experimental analysis, the GG-Rician model is investigated for amplitude and intensity SAR images of various frequency bands and scenes in comparison to state-of-the-art statistical models that include $\mathcal{K}$, Weibull, Gamma, and Lognormal. In order to decide on the most suitable model, statistical significance analysis via Kullback-Leibler divergence and Kolmogorov-Smirnov statistics are performed. The results demonstrate the superior performance and flexibility of the proposed model for all frequency bands and scenes and its applicability on both amplitude and intensity SAR images.Comment: 20 Pages, 9 figures, 8 table

Comparison of oxidation stability of virgin olive oils from different locations of Turkey

Ten kinds of virgin olive oil of two major cultivars (Ayvalık and Memecik) produced in several areas of Turkey (Bayındır, Edremit, Ortaklar, Burhaniye, Ezine, Tire, Havran, Ayvalık, Altınoluk, and Küçükkuyu) were analysed. The quality characteristics, fatty acid composition, total phenol, ando-diphenol content of the samples were determined. Oxidative stability and free radical scavenging activity were determined using Rancimat test, Schaal oven test, and DPPH method. It was found that while Memecik oil from Ortaklar demonstrated the strongest oxidative stability, Ayvalık oil from Ezine had the lowest oxidative stability among the samples. Fatty acid composition and especially oleic acid/linoleic acid ratio was previously defined as a parameter that can help distinguish cultivars from one another; however, this study proved that total phenol, especially o-diphenol content of the oil, has the strongest effect on oxidative stability compared to other factors including fatty acid composition

Evidence of threat to European economy and biodiversity following the introduction of an alien pathogen on the fungal–animal boundary

Recent years have seen a global and rapid resurgence of fungal diseases with direct impact on biodiversity and local extinctions of amphibian, coral, or bat populations. Despite similar evidence of population extinction in European fish populations and the associated risk of food aquaculture due to the emerging rosette agent Sphaerothecum destruens, an emerging infectious eukaryotic intracellular pathogen on the fungal–animal boundary, our understanding of current threats remained limited. Long-term monitoring of population decline for the 8-year post-introduction of the fungal pathogen was coupled with seasonal molecular analyses of the 18S rDNA and histological work of native fish species organs. A phylogenetic relationship between the existing EU and US strains using the ribosomal internal transcribed spacer sequences was also carried out. Here, we provide evidence that this emerging parasite has now been introduced via Pseudorasbora parva to sea bass farms, an industry that represents over 400 M€ annually in a Mediterranean region that is already economically vulnerable. We also provide for the first time evidence linking S. destruens to disease and severe declines in International Union for Conservation of Nature threatened European endemic freshwater fishes (i.e. 80% to 90 % mortalities). Our findings are thus of major economic and conservation importance

Plasticity in life history traits of the native Proterorhinus semilunaris suggests high adaptive capacity in its invasive range

Invasion risk assessments are reliant on ecological data that assist the predictions of whether an introduced species will adapt to novel conditions. Data from the native range of potential invaders can thus assist these assessments. Here, the growth and reproductive characteristics of the Western tubenose goby Proterorhinus semilunaris, a Ponto-Caspian gobiid, were assessed in three natural lakes in their native range, as there are few extant data on these traits. Across the three lakes, the gobies were found in varying abundances. Sex ratios varied, with females significantly outnumbering males in only one lake, with equal sex ratios in the other lakes. The fish always showed a positive allometric growth, but had high variability in their somatic growth rates and relative body conditions between the lakes. Scale ageing revealed all populations comprised individuals to age four years, with one lake having individuals to 5 years old. Reproductive characteristics, such as size at maturity, gonad-somatic index and fecundity, did not differ significantly between the lakes. These data suggest that plasticity in aspects of their life history traits provides P. semilunaris with considerable adaptive capacity following their introduction into novel conditions