Universal Image Steganalytic Method

In the paper we introduce a new universal steganalytic method in JPEG file format that is detecting well-known and also newly developed steganographic methods. The steganalytic model is trained by MHF-DZ steganographic algorithm previously designed by the same authors. The calibration technique with the Feature Based Steganalysis (FBS) was employed in order to identify statistical changes caused by embedding a secret data into original image. The steganalyzer concept utilizes Support Vector Machine (SVM) classification for training a model that is later used by the same steganalyzer in order to identify between a clean (cover) and steganographic image. The aim of the paper was to analyze the variety in accuracy of detection results (ACR) while detecting testing steganographic algorithms as F5, Outguess, Model Based Steganography without deblocking, JP Hide&Seek which represent the generally used steganographic tools. The comparison of four feature vectors with different lengths FBS (22), FBS (66) FBS(274) and FBS(285) shows promising results of proposed universal steganalytic method comparing to binary methods

"Microscopic" approach to the Ricci dark energy

A derivation of the Ricci dark energy from quantum field theory of fluctuating "matter" fields in a classical gravitational background is presented. The coupling to the dark energy, the parameter 'a', is estimated in the framework of our formalism, and qualitatively it appears to be within observational expectations.Comment: 7 page

A path-integral approach to polynomial invariants of links

A brief review of a self-contained genuinely three-dimensional monodromy-matrix based non-perturbative covariant path-integral approach to {\it polynomial invariants} of knots and links in the framework of (topological) quantum Chern-Simons field theory is given. An idea of ``physical'' observables represented by an auxiliary topological quantum-mechanics model in an external gauge field is introduced substituting rather a limited notion of the Wilson loop. Thus, the possibility of using various generalizations of the Chern-Simons action (also higher-dimensional ones) as well as a purely functional language becomes open. The theory is quantized in the framework of the best suited in this case {\it antibracket-antifield} formalism of Batalin and Vilkovisky. Using the Stokes theorem and formal translational invariance of the path-integral measure a {\it monodromy matrix} corresponding to an arbitrary pair of irreducible representations of an arbitrary semi-simple Lie group is derived

Gauge-Invariant Formulation of Spin-Current-Density Functional Theory

Spin-currents and non-abelian gauge potentials in electronic systems can be treated by spin-current-density functional theory, whose main input is the exchange-correlation (xc) energy expressed as a functional of spin-currents. Constructing a functional of spin currents that is invariant under U(1)$\times$SU(2) transformations is a long-standing challenge. We solve the problem by expressing the energy as a functional of a new variable we call "invariant vorticity". As an illustration we construct the xc energy functional for a two-dimensional electron gas with linear spin-orbit coupling and show that it is proportional to the fourth power of the spin current.Comment: 8 pages, 3 figures, submitte

SCORE performance in Central and Eastern Europe and former Soviet Union: MONICA and HAPIEE results

Aims: The Systematic COronary Risk Evaluation (SCORE) scale assesses 10 year risk of fatal atherosclerotic cardiovascular disease (CVD), based on conventional risk factors. The high-risk SCORE version is recommended for Central and Eastern Europe and former Soviet Union (CEE/FSU), but its performance has never been systematically assessed in the region. We evaluated SCORE performance in two sets of population-based CEE/FSU cohorts. Methods and results: The cohorts based on the World Health Organization MONitoring of trends and determinants in CArdiovascular disease (MONICA) surveys in the Czech Republic, Poland (Warsaw and Tarnobrzeg), Lithuania (Kaunas), and Russia (Novosibirsk) were followed from the mid-1980s. The Health, Alcohol, and Psychosocial factors in Eastern Europe (HAPIEE) study follows Czech, Polish (Krakow), and Russian (Novosibirsk) cohorts from 2002–05. In Cox regression analyses, the high-risk SCORE ≥5% at baseline significantly predicted CVD mortality in both MONICA [n = 15 027; hazard ratios (HR), 1.7–6.3] and HAPIEE (n = 20 517; HR, 2.6–10.5) samples. While SCORE calibration was good in most MONICA samples (predicted and observed mortality were close), the risk was underestimated in Russia. In HAPIEE, the high-risk SCORE overpredicted the estimated 10 year mortality for Czech and Polish samples and adequately predicted it for Russia. SCORE discrimination was satisfactory in both MONICA and HAPIEE. Conclusion: The high-risk SCORE underestimated the fatal CVD risk in Russian MONICA but performed well in most MONICA samples and Russian HAPIEE. This SCORE version might overestimate the risk in contemporary Czech and Polish populations

4-Dimensional BF Theory as a Topological Quantum Field Theory

Starting from a Lie group G whose Lie algebra is equipped with an invariant nondegenerate symmetric bilinear form, we show that 4-dimensional BF theory with cosmological term gives rise to a TQFT satisfying a generalization of Atiyah's axioms to manifolds equipped with principal G-bundle. The case G = GL(4,R) is especially interesting because every 4-manifold is then naturally equipped with a principal G-bundle, namely its frame bundle. In this case, the partition function of a compact oriented 4-manifold is the exponential of its signature, and the resulting TQFT is isomorphic to that constructed by Crane and Yetter using a state sum model, or by Broda using a surgery presentation of 4-manifolds.Comment: 15 pages in LaTe

Green catalysts preparation using supercritical CO2 as an antisolvent

Using rapid supercritical CO2 antisolvent precipitation, a set of nanoscaled oxide catalyst precursors have been prepared, which were further calcined to give metal oxides, such as CuMnOx(hopcalite), CeC>2, Ti02 and ZnO etc. CuMnOx(hopcalite) was used as catalyst without further modification and other single metal oxides were used as supports for gold catalysts. These materials have been characterized using a full range of techniques: XRD, Raman, FT-IR, BET surface area, SEM, DTA/TGA and XPS. Element distribution in the as-precipitated materials was evaluated by TEM-EDX. The catalytic activity of our products was evaluated by low temperature (0 25 C) CO oxidation. For CuMnOx (hopcalites), an amorphous homogenous precursor mainly composed of acetates has been prepared. Following calcinations, separated copper nanocrystals supported on manganese oxide (Cu/MnOx) has been obtained. The preliminary catalytic data show the intrinsic activity for CO oxidation of the catalyst derived from this precursor is considerably higher than the conventional CuMn204 catalysts prepared by coprecipitation, and also currently available commercial catalysts. The results clearly show that a catalyst with enhanced activity can be prepared without the presence of intimately mixed copper and manganese oxide components. In addition, using mixed solvents, such as water-ethanol and water-DMF, crystalline heterogeneous precursors have been produced. With the addition of more water to the precursor solution, there appears to be a reaction between the metal acetates CO2, and H2O. Therefore, carbonates of the metals are precipitated instead of the acetate composition. Following calcination, less crystalline or even amorphous phase-separated nanostructure final catalysts retain the high surface area, which leads higher catalytic activities than that of the current commercial hopcalite catalysts. Furthermore, using 30% H2O2 as an oxidizer and ethanol as solvent, catalysts have been prepared as well. All the as-prepared catalysts exhibit higher catalytic activities on CO oxidation when compared to those from solvents in the absence of H2O2. Novel nano-polycrystalline Ce02 was produced. When it was used as a support for gold and gold palladium nanoparticles, the catalytic data show that the activity and catalyst lifetime for CO oxidation of a gold catalyst supported on this material is much greater than that for gold supported on regular Ce02 derived from the direct calcination of cerium acetylacetonate. In addition, the Au-Pd catalysts supported on Ce02 prepared using supercritical antisolvent precipitation are amongst the most active catalysts yet reported for the selective oxidation of alcohols and the direct oxidation of hydrogen to hydrogen peroxide. Similarly, T1O2 has been produced by supercritical process. When using it as a support for gold nanoparticles, the activity and stability for CO oxidation of a gold catalyst supported on this material is much greater than that for gold supported on regular Ti02 derived from the direct calcination of titanium oxide acetylacetonate. Finally, ZnO was prepared using supercritical process and then was used as supports for gold particles as well. The catalytic data show that it can give very high activity for CO oxidation.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Cross-shell excitation in two-proton knockout: Structure of 52^{52}Ca

The two-proton knockout reaction $^9$Be($^{54}$Ti,$^{52}$Ca$+ \gamma$) has been studied at 72 MeV/nucleon. Besides the strong feeding of the $^{52}$Ca ground state, the only other sizeable cross section proceeds to a 3$^-$ level at 3.9 MeV. There is no measurable direct yield to the first excited 2$^+$ state at 2.6 MeV. The results illustrate the potential of such direct reactions for exploring cross-shell proton excitations in neutron-rich nuclei and confirms the doubly-magic nature of $^{52}$Ca

Optimization of the MALDIxin test for the rapid identification of colistin resistance in Klebsiella pneumoniae using MALDI-TOF-MS

Background. With the dissemination of carbapenemase producers, a revival of colistin was observed for the treatment of infections caused by multidrug-resistant Gram-negatives. Unfortunately, the increasing usage of colistin led to the emergence of resistance. In Klebsiella pneumoniae, colistin resistance arises through addition of L-arabinose-4N (L-Ara4N) or phosphoethanolamine (pEtN) on the native lipid A. The underlying mechanisms involve numerous chromosome-encoded genes or the plasmid-encoded phosphoethanolamine transferase MCR. Currently, detection of colistin resistance is time consuming since it still relies on MIC determination by broth microdilution. Recently, a rapid diagnostic test based on MALDI-TOF detection of modified lipid A was developed (the MALDIxin test) and tested on Escherichia coli and Acinetobacter baumannii. Objectives. Optimize the MALDIxin test for the rapid detection of colistin resistance in Klebsiella pneumoniae. Methods. This optimization consists on an additional mild-acid hydrolysis of 15 min in 1% acetic acid. The optimized method was tested on a collection of 81 clinical K. pneumoniae isolates including 49 colistin resistant strains among which 45 correspond to chromosome-encoded resistance, 3 MCR-related resistance and one isolate harbouring both mechanisms. Results. The optimized method allowed the rapid (< 30 min) identification of L-Ara4N and pEtN modified lipid A of K. pneumoniae which are known to be the real triggers of polymyxin resistance. In the same time, it discriminates between chromosome-encoded and MCR-related polymyxin resistance. Conclusions. The MALDIxin test has the potential to become an accurate tool for the rapid diagnostic of colistin resistance in clinically-relevant Gram negative bacteria