39 research outputs found

    Systematic model behavior of adsorption on flat surfaces

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    A low density film on a flat surface is described by an expansion involving the first four virial coefficients. The first coefficient (alone) yields the Henry's law regime, while the next three correct for the effects of interactions. The results permit exploration of the idea of universal adsorption behavior, which is compared with experimental data for a number of systems

    Lattice QCD Constraints on the Nuclear Equation of State

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    Based on the quasi-particle description of the QCD medium at finite temperature and density we formulate the phenomenological model for the equation of state that exhibits crossover or the first order deconfinement phase transition. The models are constructed in such a way to be thermodynamically consistent and to satisfy the properties of the ground state nuclear matter comply with constraints from intermediate heavy--ion collision data. Our equations of states show quite reasonable agreement with the recent lattice findings on temperature and baryon chemical potential dependence of relevant thermodynamical quantities in the parameter range covering both the hadronic and quark--gluon sectors. The model predictions on the isentropic trajectories in the phase diagram are shown to be consistent with the recent lattice results. Our nuclear equations of states are to be considered as an input to the dynamical models describing the production and the time evolution of a thermalized medium created in heavy ion collisions in a broad energy range from SIS up to LHC.Comment: 13 pages, 11 figure

    Searching for a Cosmological Preferred Axis: Union2 Data Analysis and Comparison with Other Probes

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    We review, compare and extend recent studies searching for evidence for a preferred cosmological axis. We start from the Union2 SnIa dataset and use the hemisphere comparison method to search for a preferred axis in the data. We find that the hemisphere of maximum accelerating expansion rate is in the direction (l,b)=(3093+23,1810+11)(l,b)=({309^\circ}^{+23^\circ}_{-3^\circ}, {18^\circ}^{+11^\circ}_{-10^\circ}) (\omm=0.19) while the hemisphere of minimum acceleration is in the opposite direction (l,b)=(1293+23,1811+10)(l,b)=({129^\circ}^{+23^\circ}_{-3^\circ},{-18^\circ}^{+10^\circ}_{-11^\circ}) (\omm=0.30). The level of anisotropy is described by the normalized difference of the best fit values of \omm between the two hemispheres in the context of \lcdm fits. We find a maximum anisotropy level in the Union2 data of \frac{\Delta \ommax}{\bomm}=0.43\pm 0.06. Such a level does not necessarily correspond to statistically significant anisotropy because it is reproduced by about 3030% of simulated isotropic data mimicking the best fit Union2 dataset. However, when combined with the axes directions of other cosmological observations (bulk velocity flow axis, three axes of CMB low multipole moments and quasar optical polarization alignment axis), the statistical evidence for a cosmological anisotropy increases dramatically. We estimate the probability that the above independent six axes directions would be so close in the sky to be less than 11%. Thus either the relative coincidence of these six axes is a very large statistical fluctuation or there is an underlying physical or systematic reason that leads to their correlation.Comment: 10 pages, 7 figures. Accepted in JCAP (to appear). Extended analysis with redshift tomography of SnIa, included errorbars and increased number of axes. The Mathematica 7 files with the data used for the production of the figures along with a Powerpoint file with additional figures may be downloaded from http://leandros.physics.uoi.gr/anisotrop

    Fine-Scale Mapping of the 4q24 Locus Identifies Two Independent Loci Associated with Breast Cancer Risk

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    Background: A recent association study identified a common variant (rs9790517) at 4q24 to be associated with breast cancer risk. Independent association signals and potential functional variants in this locus have not been explored. Methods: We conducted a fine-mapping analysis in 55,540 breast cancer cases and 51,168 controls from the Breast Cancer Association Consortium. Results: Conditional analyses identified two independent association signals among women of European ancestry, represented by rs9790517 [conditional P = 2.51 × 10−4; OR, 1.04; 95% confidence interval (CI), 1.02–1.07] and rs77928427 (P = 1.86 × 10−4; OR, 1.04; 95% CI, 1.02–1.07). Functional annotation using data from the Encyclopedia of DNA Elements (ENCODE) project revealed two putative functional variants, rs62331150 and rs73838678 in linkage disequilibrium (LD) with rs9790517 (r2 ≥ 0.90) residing in the active promoter or enhancer, respectively, of the nearest gene, TET2. Both variants are located in DNase I hypersensitivity and transcription factor–binding sites. Using data from both The Cancer Genome Atlas (TCGA) and Molecular Taxonomy of Breast Cancer International Consortium (METABRIC), we showed that rs62331150 was associated with level of expression of TET2 in breast normal and tumor tissue. Conclusion: Our study identified two independent association signals at 4q24 in relation to breast cancer risk and suggested that observed association in this locus may be mediated through the regulation of TET2. Impact: Fine-mapping study with large sample size warranted for identification of independent loci for breast cancer risk

    Rockfall susceptibility map for Athinios port, Santorini Island, Greece

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    This article analyzes rockfall susceptibility in the steep caldera slopes upstream of Athinios port, Santorini Island, Greece. The study area is situated in the internal rim of a submarine caldera where the most important problem that is recorded is the frequent rockfalls that not only cause damages to roads and vehicles but also pose a threat to people that are transported or located on the port. As a result, a methodology which combines information relatively to surficial and engineering geology, geomorphological processes, and structural analysis was adopted. The methodology incorporates evenly a maximum runout map generated by means of reach probability of rock block analysis, using the empirical model of "reach angle". Additionally volumes of rockfall events categorized and presented through a map to assist the compilation of rockfall susceptibility map which allows us to identify areas and human activities exposed to these incidents and set up several protection meters. © 2009 Elsevier B.V

    The ιmpact of εarthquake-ρelated γeohazards on οffshore πipelines and σeaside φacilities of the οil and gas industry in the Mediterranean region

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    Summarization: The transportation of hydrocarbons to Central and Northern Europe is currently being performed by high-pressure onshore pipelines coming mainly from Central Asia. In the next decades the increased demand for energy in European countries will undoubtedly require the smooth and safe transfer of hydrocarbons from the East Mediterranean, Middle East and North Africa. This process is expected to be performed using offshore pipeline networks and seaside facilities connecting various countries in the wider Mediterranean region. However, since the Mediterranean basin is characterized by moderate to high seismicity, the seismic design of any offshore pipeline or seaside facility should aim to eliminate the probability of occurrence of a potential accident such as explosion, fire, leakage, etc., and their devastating consequences. This goal may be achieved through: (a) the identification and the quantification of the potential geohazards, and (b) the realistic verification of the integrity of offshore pipelines and/or seaside facilities. Apart from strong ground motion, the potential earthquake-related geohazards include mainly coastal or submarine landslides, active faults, soil liquefaction phenomena and, in some cases, tsunamis. For this purpose, after a short presentation of the topography, bathymetry, geology, tectonics and seismicity that characterize the Mediterranean region, the main earthquake-related geohazards are briefly described. In addition, this study proposes certain technically and economically feasible mitigation/protection measures.Παρουσιάστηκε στο: The Fourteenth International Conference on Civil, Structural and Environmental Engineerin

    Comorbidity of obsessive-compulsive disorder in bipolar spectrum disorders: Systematic review and meta-analysis of its prevalence

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    Background: Obsessive-compulsive disorder (OCD) is often comorbid with Bipolar Disorder (BD), complicating its presentation and management. OCD prevalence rates in BD vary widely across studies and recent meta-analyses. Objective: We performed a comprehensive systematic review and meta-analysis of studies reporting cross-sectional or lifetime OCD prevalence in BD, assessed by meta-regression various determinants of estimated prevalence and compared it with major depressive disorder (MDD) patients and general population subjects included in extracted studies. Methods: Relevant articles published up to January 2019 in PubMed/MEDLINE were retrieved. Prevalence rates underwent Freeman–Tukey double arcsine transformation before meta-analysis. Results: We included 29 studies reporting cross-sectional prevalence (N = 6109) and 39 studies reporting lifetime prevalence (N = 8205); eight studies reported both. The pooled lifetime and cross-sectional prevalence of comorbid OCD in BD was estimated at 10.9% (95% CI: 7.8–14.4%) and 11.2% (7.6–15.3%), respectively, in the random-effects model. Respective estimates in the general population were 2.5% and 1.6%. Study setting (epidemiological or clinical), diagnostic criteria and procedures, gender, BD subtype and remission status could not explain heterogeneity of prevalence estimates in meta-regressions. Age had a small yet significant negative correlation with lifetime prevalence. OCD prevalence in BD was not significantly different than in MDD. Limitations: Search was limited to English-language literature. Conclusions: Lifetime OCD prevalence in BD was 4.4 times higher than in the general population. Cross-sectional prevalence was as high as lifetime, suggesting that OCD in BD is more chronic/ persistent than in the general population, where cross-sectional stands at about two thirds the lifetime prevalence. © 201
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