Measures and Limits of Models of Fixation Selection

Models of fixation selection are a central tool in the quest to understand how the human mind selects relevant information. Using this tool in the evaluation of competing claims often requires comparing different models' relative performance in predicting eye movements. However, studies use a wide variety of performance measures with markedly different properties, which makes a comparison difficult. We make three main contributions to this line of research: First we argue for a set of desirable properties, review commonly used measures, and conclude that no single measure unites all desirable properties. However the area under the ROC curve (a classification measure) and the KL-divergence (a distance measure of probability distributions) combine many desirable properties and allow a meaningful comparison of critical model performance. We give an analytical proof of the linearity of the ROC measure with respect to averaging over subjects and demonstrate an appropriate correction of entropy-based measures like KL-divergence for small sample sizes in the context of eye-tracking data. Second, we provide a lower bound and an upper bound of these measures, based on image-independent properties of fixation data and between subject consistency respectively. Based on these bounds it is possible to give a reference frame to judge the predictive power of a model of fixation selection . We provide open-source python code to compute the reference frame. Third, we show that the upper, between subject consistency bound holds only for models that predict averages of subject populations. Departing from this we show that incorporating subject-specific viewing behavior can generate predictions which surpass that upper bound. Taken together, these findings lay out the required information that allow a well-founded judgment of the quality of any model of fixation selection and should therefore be reported when a new model is introduced

Predicting Eye Fixations on Complex Visual Stimuli Using Local Symmetry

Most bottom-up models that predict human eye fixations are based on contrast features. The saliency model of Itti, Koch and Niebur is an example of such contrast-saliency models. Although the model has been successfully compared to human eye fixations, we show that it lacks preciseness in the prediction of fixations on mirror-symmetrical forms. The contrast model gives high response at the borders, whereas human observers consistently look at the symmetrical center of these forms. We propose a saliency model that predicts eye fixations using local mirror symmetry. To test the model, we performed an eye-tracking experiment with participants viewing complex photographic images and compared the data with our symmetry model and the contrast model. The results show that our symmetry model predicts human eye fixations significantly better on a wide variety of images including many that are not selected for their symmetrical content. Moreover, our results show that especially early fixations are on highly symmetrical areas of the images. We conclude that symmetry is a strong predictor of human eye fixations and that it can be used as a predictor of the order of fixation

The Biodiversity of the Mediterranean Sea: Estimates, Patterns, and Threats

The Mediterranean Sea is a marine biodiversity hot spot. Here we combined an extensive literature analysis with expert opinions to update publicly available estimates of major taxa in this marine ecosystem and to revise and update several species lists. We also assessed overall spatial and temporal patterns of species diversity and identified major changes and threats. Our results listed approximately 17,000 marine species occurring in the Mediterranean Sea. However, our estimates of marine diversity are still incomplete as yet—undescribed species will be added in the future. Diversity for microbes is substantially underestimated, and the deep-sea areas and portions of the southern and eastern region are still poorly known. In addition, the invasion of alien species is a crucial factor that will continue to change the biodiversity of the Mediterranean, mainly in its eastern basin that can spread rapidly northwards and westwards due to the warming of the Mediterranean Sea. Spatial patterns showed a general decrease in biodiversity from northwestern to southeastern regions following a gradient of production, with some exceptions and caution due to gaps in our knowledge of the biota along the southern and eastern rims. Biodiversity was also generally higher in coastal areas and continental shelves, and decreases with depth. Temporal trends indicated that overexploitation and habitat loss have been the main human drivers of historical changes in biodiversity. At present, habitat loss and degradation, followed by fishing impacts, pollution, climate change, eutrophication, and the establishment of alien species are the most important threats and affect the greatest number of taxonomic groups. All these impacts are expected to grow in importance in the future, especially climate change and habitat degradation. The spatial identification of hot spots highlighted the ecological importance of most of the western Mediterranean shelves (and in particular, the Strait of Gibraltar and the adjacent Alboran Sea), western African coast, the Adriatic, and the Aegean Sea, which show high concentrations of endangered, threatened, or vulnerable species. The Levantine Basin, severely impacted by the invasion of species, is endangered as well

Taxonomic relationships in genus Fritillaria (Liliaceae): Evidence from RAPD-PCR and SDS-PAGE of seed proteins

The genus Fritillaria L. is one of the examples from the several unsolved taxonomic problems. The classical identification of plant depends on morphological characteristics. Therefore, it is difficult to determine the botanical origin of some plants. The goals of this study were to examine the taxonomic status of these 42 taxa of Fritillaria in Turkey by means of RAPD-PCR and seed protein analysis in addition to taxonomic interpretation of species. SDS-PAGE and RAPD-PCR techniques were used to help taxonomic interpretation of Fritillaria species. Dendrogram based on genetic distances was calculated using the computer programmed PopGen. For the RAPD-PCR analysis, 40 random primers were tested in the amplification reactions with Fritillaria species. Only 9 of them gave consistently reproducible banding patterns. The analysis of seed proteins showed that all studied genotypes had a specific protein pattern except the species that were close to each other based on morphological data. In electrophoretic protein banding patterns a total of 22-30 protein bands were observed. The protein bands in the region between 116-66 kDa were almost similar in all the species tested. In addition to that, all the species of Fritillaria had two bands in common (just bigger than 25 kDa). F. acmopetala subsp. acmopetala and F. sororum are very close relatives according to morphological, RAPD and protein results. Therefore these two taxa can be considered as synonyms. F. zagrica, F. caucasica, F. baskilensis, F. armena and F. pinardii are grouped together. All these separate species treated as synonyms based on morphological and molecular data. © 2008 Akadémiai Kiadó

Taxonomic relationships in genus Fritillaria (Liliaceae): Evidence from RAPD-PCR and SDS-PAGE of seed proteins

The genus Fritillaria L. is one of the examples from the several unsolved taxonomic problems. The classical identification of plant depends on morphological characteristics. Therefore, it is difficult to determine the botanical origin of some plants. The goals of this study were to examine the taxonomic status of these 42 taxa of Fritillaria in Turkey by means of RAPD-PCR and seed protein analysis in addition to taxonomic interpretation of species. SDS-PAGE and RAPD-PCR techniques were used to help taxonomic interpretation of Fritillaria species. Dendrogram based on g enetic distances was calculated using the computer programmed PopGen. For the RAPD-PCR analysis, 40 random primers were tested in the amplification reactions with Fritillaria species. Only 9 of them gave consistently reproducible banding patterns. The analysis of seed proteins showed that all studied genotypes had a specific protein pattern except the species that were close to each other based on morphological data. In electrophoretic protein banding patterns a total of 22–30 protein bands were observed. The protein bands in the region between 116-66 kDa were almost similar in all the species tested. In addition to that, all the species of Fritillaria had two bands in common (just bigger than 25 kDa). F. acmopetala subsp. acmopetala and F. sororum are very close relatives according to morphological, RAPD and protein results. Therefore these two taxa can be considered as synonyms. F. zagrica , F. caucasica , F. baskilensis , F. armena and F. pinardii are grouped together. All these separate species treated as synonyms based on morphological and molecular data

Cephalaria duzceënsis (Dipsacaceae), a new species from the western Black Sea region, Turkey

A new species, Cephalaria duzceënsis N. Aksoy & R. S. Göktürk (Dipsacacae) from western Black Sea region of Turkey is described. It is illustrated in line drawings and the morphology of the new species is compared with Cephalaria speciosa. Molecular and morphological methods were used to separate the two species. Both species were first identified morphologically and then studied by randomly amplified polymorphic DNA (RAPD) markers. Genetic similarities were calculated based on the RAPD data and used to construct a UPGMA dendrogram. According to the result, two main clusters were observed using the character differences. It is concluded that C. duzceënsis sp. nov. is different from C. speciosa. © 2007 The Authors

Phosphorus-nitrogen compounds. Part 42. the comparative syntheses of 2-: Cis -4-ansa(N/O) and spiro(N/O) cyclotetraphosphazene derivatives: Spectroscopic and crystallographic characterization, antituberculosis and cytotoxic activity studies

The reaction of N4P4Cl8 (1) with one equimolar amount of the sodium salt of an N/O donor-type bidentate ligand (2) afforded two kinds of derivatives, namely, mono-ferrocenyl-2-cis-4-dichloro-ansa- (2,4-ansa; 3) and mono-ferrocenyl-spiro- (spiro; 4) hexachlorocyclotetraphosphazenes. The reaction yield (35%) of 4 was significantly larger than that of 3 (14%). The 2,4-ansa compound (3) was reacted with excess secondary amines to produce 2-cis-4-dichloro-ansa-cyclotetraphosphazenes (3a-3d). On the other hand, the spiro compound (4) gave fully substituted mono-ferrocenyl-spiro-cyclotetraphosphazenes (4a-4d) with excess monoamines as well. The tetrameric phosphazene derivatives were characterized by ESI-MS and/or HRMS, FTIR, HSQC, HMBC, 1H, 13C, and 31P NMR spectroscopy and X-ray crystallography (for 4). It is observed that the 2,4-ansa and spiro-cyclotetraphosphazenes have different thermal stabilities. Additionally, the CVs of the new mono-ferrocenyl pendant-armed cyclotetraphosphazenes revealed electrochemically reversible one-electron oxidation of the Fe-redox centre. The 2,4-ansa phosphazenes (3 and 3a-3d) have two different stereogenic P centers indicating that they are expected to be in racemic mixtures (RR?/SS?). The chiralities of 3a and 3c were investigated by chiral HPLC. The manuscript also deals with the antimicrobial activities against G(+)/G(-) bacteria and fungi, the interactions with plasmid DNA, the in vitro cytotoxic activities against L929 fibroblast and MCF7 breast cells, and the antituberculosis activities against Mycobacterium tuberculosis H37Rv of the cyclotetraphosphazenes. © 2019 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.Hacettepe Üniversitesi: 013 D04 602 004Türkiye Bilimler AkademisiTürkiye Bilimsel ve Teknolojik Araştirma Kurumu, TÜBITAK: 215Z496The authors thank the ‘‘Scientific and Technical Research Council of Turkey’’ (Grant No. 215Z496). T. H. is grateful to Hacettepe University Scientific Research Project Unit (Grant No. 013 D04 602 004), and Z. K. thanks the Turkish Academy of Sciences (TÜBA) for partial support of this work

Acil sağlık çalışanlarında işe bağlı gerginlik, stresle başa çıkma yollarını kullanma durumu ve etkileyen faktörler

Objective: The purpose of the study is to determine work-related tension, using the methods of overcoming the stress and the affecting factors in emergency staff Material and Methods: The universe of the study in descriptive type is consisted of health team members in institutions rendering emergency health service belong to public sector in Turkey. Turkey was divided into 4 clusters (east, west, south and north) by taking the geographical settlement areas into consideration and a province was selected from each cluster in random. The number of people within the scope of the research is 769 and 560 people was reached (response rate is 72.82%). Approval of ethical committee and written permissions were acquired from the related institutions before the research. There are questions including the demographic characteristics of the participants and their opinions on the job in first section of the form in which data were gathered, and “Work-Related Tension Scale-WRTS” in the second section, and “Overcoming the Stress Scale-OSS” in the third section. The data were recorded in statistical program. The averages were given with standard deviations and p<0.05 was accepted as meaningful. Frequency analysis was carried out in the evaluation of the data and, Mann Whitney U test, Kruskall Wallis test and Spearman Correlation Analysis were implemented. Results: Average of age of the participants was 29.71±7.92 years. WRTS point average was 49.80±5.92 and was found high in young people, having low education level, in emergency medical technicians (EMT), the ones working on contract, having negative point of view against the occupation (p<0.05). OSS point average of the participants was 56.56±11.23. Conclusion: It was detected that WRTS point average in the participants was over scale point average and OSS point average was under scale point average. In health personnel rendering emergency service; service and training studies that will increase the level of using overcoming the stress methods, decrease the work-related tension and improve affecting factors should be given priority. © 2016 by Türkiye Klinikleri