17,551 research outputs found

    Obfuscation-based malware update: A comparison of manual and automated methods

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    Indexación: Scopus; Web of Science.This research presents a proposal of malware classification and its update based on capacity and obfuscation. This article is an extension of [4]a, and describes the procedure for malware updating, that is, to take obsolete malware that is already detectable by antiviruses, update it through obfuscation techniques and thus making it undetectable again. As the updating of malware is generally performed manually, an automatic solution is presented together with a comparison from the standpoint of cost and processing time. The automated method proved to be more reliable, fast and less intensive in the use of resources, specially in terms of antivirus analysis and malware functionality checking times.http://univagora.ro/jour/index.php/ijccc/article/view/2961/112

    Conduction Electrons Mediating The Evolution From Antiferromagnetic To Ferromagnetic Ordering In Gd(co1-yfey)(2)zn-20 (0 <= Y <= 1)

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    Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)GdFe2Zn20 is a complex cagelike compound with an unusually high ferromagnetic ordering temperature (T-C = 86 K) for a very diluted Gd3+ magnetic sublattice, embedded in a matrix that features strong electronelectron correlations. Here, we report on a magnetic and electronic study of the substitutional intermetallic system Gd(Co1-y Fe-y)(2)Zn-20 combining magnetizationmeasurements plus first-principles density functional theory (DFT) calculations with temperature-dependent electron spin resonance (ESR). After accounting for electron-electron correlations and itinerant molecular field effects, the ESR results indicate that the exchange interaction between the Gd3+ is processed via a single band of d-type electrons at the Fermi level and the exchange interaction is covalent in nature [J(0)(fd) < 0] with a strong conduction electron (ce) momentum transfer dependence [Jfd (q)]. The DFT calculations support this scenario by indicating a major contribution of d-type ce at the Fermi level and a spin polarization in (Y, Gd) Fe2Zn20 wherein the most stable configuration is antiferromagnetic between Gd3+ and ce spins. Our results demonstrate that the standard Ruderman-Kittel-Kasuya-Yosida mechanism cannot explain the ferromagnetic behavior of GdFe2Zn20 and a superexchangelike mechanism is proposed for this magnetic interaction. An "extended phase diagram" for the double substitution sequence YCo2Zn20. GdCo2Zn20. GdFe2Zn20 is presented and discussed.9510Brazilian agencies FAPESP [2011/19924-2, 2012/17562-9]CNPqFINEPCAPESFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

    Conduction electrons in aperiodic versus periodic structures: an ESR study of quasicrystalline i-Y(Gd)-Cd and its approximant Y(Gd)Cd-6

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    FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORA formal description of collective electronic states in condensed-matter systems lacking long-range periodicity remains a theoretical challenge. To experimentally explore the differences in electronic and magnetic behavior between metallic quasicrystals (QCs) and their conventional crystalline analogs [quasicrystal approximants (QCAs)], we have grown single crystals of Y1-xGdx-Cd6 (QCA) together with their QC counterparts i-Y1-xGdx-Cd for x = 0.006, 0.01, 0.1, and 1.00, and we carried out comparative T-dependent electron spin resonance (ESR) measurements. On the high Gd concentration side, x = 1.00, we confirm that GdCd6 adopts an antiferromagnetic ground state below T-N similar to 22 K, whereas i-Gd-Cd presents spin-glass-like behavior showing similar local and dynamical properties from the point of view of ESR. For the diluted samples, our ESR experimental results show similar local conduction electron polarization behavior at the Gd3+ site in all QC/QCA pairs investigated, supporting the validity of using QCAs as periodic representations of QCs in terms of short-range electronic interactions. However, there is a measurable difference in the Korringa relaxation rate (spin-flip relaxation process between the localized Gd3+ 4f electron and the delocalized s-type conduction electrons at the Fermi surface) between the QC/QCA pairs probably associated with the lack of periodicity. We expect that our comparative ESR study may provide support and motivation for the development of new theoretical approaches toward a generalized band-structure theory, contemplating condensed-matter systems beyond the scope of traditional periodicity.100117FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIOR2016/15780-02011/19924-2Sem informaçãoSem informaçã

    Eu2+ spin dynamics in the filled skutterudites EuM4Sb12 (M = Fe, Ru, Os)

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    We report evidence for a close relation between the thermal activation of the rattling motion of the filler guest atoms, and inhomogeneous spin dynamics of the Eu2+ spins. The spin dynamics is probed directly by means of Eu2+ electron spin resonance (ESR), performed in both X-band (9.4 GHz) and Q-band (34 GHz) frequencies in the temperature interval 4.2 < T < 300 K. A comparative study with ESR measurements on the Beta-Eu8Ga16Ge30 clathrate compound is presented. Our results point to a correlation between the rattling motion and the spin dynamics which may be relevant for the general understanding of the dynamics of cage systems.Comment: 6 pages, 4 figures, accepted for publication in Phys. Rev.

    Datasets for transcriptomics, q-proteomics and phenotype microarrays of polyphosphate metabolism mutants from Escherichia coli

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    Indexación: Scopus.Author acknowledges Fondecyt Grants 1120209, 1121170 and Anillo ACT-1107Here, we provide the dataset associated with our research article on the polyphosphate metabolism entitled, “Multi-level evaluation of Escherichia coli polyphosphate related mutants using global transcriptomic, proteomic and phenomic analyses”. By integrating different omics levels (transcriptome, proteome and phenome), we were able to study Escherichia coli polyphosphate mutant strains (Δppk1, Δppx, and Δppk1-ppx). We have compiled here all datasets from DNA microarrys, q-proteomic (Isotope-Coded Protein Labeling, ICPL) and phenomic (Phenotype microarray) raw data we have obtained in all polyP metabolism mutants.http://www.sciencedirect.com/science/article/pii/S2352340917300860?via%3Dihu

    Trion dynamics in coupled double quantum wells. Electron density effects

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    We have studied the coherent dynamics of injected electrons when they are either free or bounded both in excitons and in trions (charged excitons). We have considered a remotely doped asymmetric double quantum well where an excess of free electrons and the direct created excitons generate trions. We have used the matrix density formalism to analyze the electron dynamics for different concentration of the three species. Calculations show a significant modification of the free electron inter-sublevel oscillations cWe have studied the coherent dynamics of injected electrons when they are aused by electrons bound in excitons and trions. Based on the present calculations we propose a method to detect trions through the emitted electromagnetic radiation or the current density.Comment: 14 pages, 13 figure
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