Coherent control of the cooperative branching ratio for nuclear x-ray pumping

Coherent control of nuclear pumping in a three level system driven by x-ray light is investigated. In single nuclei, the pumping performance is determined by the branching ratio of the excited state populated by the x-ray pulse. Our results are based on the observation that in ensembles of nuclei, cooperative excitation and decay leads to a greatly modified nuclear dynamics, which we characterize by a time-dependent cooperative branching ratio. We discuss prospects of steering the x-ray pumping by coherently controlling the cooperative decay. First, we study an ideal case with purely superradiant decay and perfect control of the cooperative emission. A numerical analysis of x-ray pumping in nuclear forward scattering with coherent control of the cooperative decay via externally applied magnetic fields is presented. Next, we provide an extended survey of nuclei suitable for our scheme, and propose proof-of-principle implementations already possible with typical M\"ossbauer nuclear systems such as $^{57}\mathrm{Fe}$. Finally, we discuss the application of such control techniques to the population or depletion of long-lived nuclear states.Comment: 11 pages, 8 figures; updated to the published versio

Spectrum of Light in a Quantum Fluctuating Periodic Structure

We address the general problem of the excitation spectrum for light coupled to scatterers having quantum fluctuating positions around the sites of a periodic lattice. In addition to providing an imaginary part to the spectrum, we show that these quantum fluctuations affect the real part of the spectrum, in a way that we determine analytically. Our predictions may be observed with ultracold atoms in an optical lattice, on a J=0->J'=1 narrow atomic transition. As a side result, we resolve a controversy for the occurrence of a spectral gap in a fcc lattice.Comment: 4 pages, 1 figure; introduction, conclusion and title change

Hydrogen-induced rupture of strained Si─O bonds in amorphous silicon dioxide

Using ab initio modeling we demonstrate that H atoms can break strained Si─O bonds in continuous amorphous silicon dioxide (a−SiO2) networks, resulting in a new defect consisting of a threefold-coordinated Si atom with an unpaired electron facing a hydroxyl group, adding to the density of dangling bond defects, such as E′ centers. The energy barriers to form this defect from interstitial H atoms range between 0.5 and 1.3 eV. This discovery of unexpected reactivity of atomic hydrogen may have significant implications for our understanding of processes in silica glass and nanoscaled silica, e.g., in porous low-permittivity insulators, and strained variants of a−SiO2

Modulational instability of bright solitary waves in incoherently coupled nonlinear Schr\"odinger equations

We present a detailed analysis of the modulational instability (MI) of ground-state bright solitary solutions of two incoherently coupled nonlinear Schr\"odinger equations. Varying the relative strength of cross-phase and self-phase effects we show existence and origin of four branches of MI of the two-wave solitary solutions. We give a physical interpretation of our results in terms of the group velocity dispersion (GVD) induced polarization dynamics of spatial solitary waves. In particular, we show that in media with normal GVD spatial symmetry breaking changes to polarization symmetry breaking when the relative strength of the cross-phase modulation exceeds a certain threshold value. The analytical and numerical stability analyses are fully supported by an extensive series of numerical simulations of the full model.Comment: Physical Review E, July, 199

Методологические особенности валидации судебно-экспертных методик

The article reviews and summarizes the experience of validating forensic expert techniques in the Russian Federal Centre of Forensic Science of the Ministry of Justice of the Russian Federation. The authors point out the methodological features of practical implementation of the validation procedure. They demonstrate that the specificity, diversity, and complexity of the objects of expert study require the classification of the applied methods in terms of metrology, identification of the main validation parameters of quantitative and qualitative methods, organization of experiments, and evaluation of validation parameters using mathematical analysis methods. They also propose to divide methods into two types: forensic expert measurement methods (FMT) and forensic expert testing methods (FTT). Based on the generalization of information presented in several regulatory documents and scientific publications, the following parameters are identified for FMT: metrological characteristics or properties of the method (specificity, linearity, sensitivity, range of determined values, detection limit, quantitative determination limit) and quality indicators of the method (precision, correctness, accuracy of the analysis result, or uncertainty). When validating FTT, it is proposed to evaluate the reliability of the method and the competence of the expert.An experiment to assess validation parameters is performed using enough control samples with established characteristics of controlled indicators and with the participation of a sufficient number of experts. Requirements for control samples are provided.The authors also give examples of probabilistic evaluation of validation parameters for two qualitative testing methods: microscopic examination of textile fibers and detection of gunshot residue using scanning electron microscopy and X-ray microanalysis. The reliability of these methods is assessed by calculating the likelihood ratio, and the specificity of interpreting the results of FMT and FTT validation is noted.The decision on compliance with the requirements is made if the interval of the established extended uncertainty for the obtained result does not exceed the tolerance field. In the absence of tolerances, FMT is considered suitable for solving forensic expert tasks if the values of the extended uncertainty of the measurement results of the controlled indicator do not exceed the values established during validation. For FTT, a low probabilistic proportion of false positive and false negative results in determining the presence/absence of controlled indicators, as well as experimentally confirmed competence of the expert during validation, are indicators of the suitability of the method for its intended useВ статье представлен обзор и обобщение опыта валидации судебно-экспертных методик (СЭМ) в ФБУ РФЦСЭ при Минюсте России. Отмечены методологические особенности практической реализации процедуры валидации. Показано, что специфичность, разнообразие и сложность объектов экспертного исследования требуют классификации используемых методик в метрологическом плане, выявления основных параметров валидации количественных и качественных методик, организации эксперимента и оценки параметров валидации с применением математических методов анализа. Предлагается разделять методики на два типа: судебноэкспертные методики измерения (СЭМИ) и судебно-экспертные методики тестирования (СЭМТ). На основании обобщения сведений, представленных в ряде нормативных документов и научных публикаций, для СЭМИ выделены следующие параметры: метрологические характеристики или свойства методики (специфичность, линейность, чувствительность, диапазон определяемых величин, предел обнаружения, предел количественного определения) и показатели качества методики (прецизионность, правильность, точность результата анализа или неопределенность). При валидации СЭМТ предложено оценивать надежность методики и компетентность эксперта.Эксперимент по оценке параметров валидации выполняют с использованием достаточного количества контрольных образцов с установленными характеристиками контролируемых показателей и с участием достаточного числа экспертов. Приведены требования, предъявляемые к контрольным образцам.Разобраны примеры вероятностной оценки параметров валидации для двух качественных методик тестирования: по микроскопическому исследованию текстильных волокон и по обнаружению следов продуктов выстрела с помощью сканирующей электронной микроскопии и рентгеноспектрального микроанализа. Дана оценка надежности этих методик с помощью расчета отношения правдоподобия, отмечена специфика интерпретации результатов валидации СЭМИ и СЭМТ.Решение о соответствии СЭМИ предъявленным требованиям принимается, если интервал установленной расширенной неопределенности для полученного результата не выходит за пределы поля допуска. При отсутствии допусков СЭМИ считается пригодной для решения судебноэкспертных задач, если значения расширенной неопределенности результатов измерений контролируемого показателя не превышают значений, установленных при валидации. Для СЭМТ низкая вероятностная доля ложноположительных и ложноотрицательных результатов установления наличия/отсутствия контролируемых показателей, а также экспериментально подтвержденная компетентность эксперта в ходе валидации являются показателями пригодности методики для цели использовани

Analysis and Reuse of Plots Using Similarity and Analogy

Abstract: A plot is a partially ordered set of events. Plot analysis is a relevant source of knowledge about the agents behavior when accessing data stored in the database. It relies on logical logs which register the actions of individual agents. This paper proposes techniques to analyze and reuse plots based on the concepts of similarity and analogy, borrowed from cognitive science and linguistics. The concept of similarity is applied to organize plots as a library, and to explore the reuse of plots in the same domain. By contrast, the concept of analogy helps reuse plots across different domains. The techniques proposed in this paper find applications in areas such as computer games and emergency response information systems, as well as some traditional business applications

Reactivity of Metal-Free and Metal-Associated Amyloid-?? with Glycosylated Polyphenols and Their Esterified Derivatives

Both amyloid-?? (A??) and transition metal ions are shown to be involved in the pathogenesis of Alzheimer???s disease (AD), though the importance of their interactions remains unclear. Multifunctional molecules, which can target metal-free and metal-bound A?? and modulate their reactivity (e.g., A?? aggregation), have been developed as chemical tools to investigate their function in AD pathology; however, these compounds generally lack specificity or have undesirable chemical and biological properties, reducing their functionality. We have evaluated whether multiple polyphenolic glycosides and their esterified derivatives can serve as specific, multifunctional probes to better understand AD. The ability of these compounds to interact with metal ions and metal-free/-associated A??, and further control both metal-free and metal-induced A?? aggregation was investigated through gel electrophoresis with Western blotting, transmission electron microscopy, UV-Vis spectroscopy, fluorescence spectroscopy, and NMR spectroscopy. We also examined the cytotoxicity of the compounds and their ability to mitigate the toxicity induced by both metal-free and metal-bound A??. Of the polyphenols investigated, the natural product (Verbascoside) and its esterified derivative (VPP) regulate the aggregation and cytotoxicity of metal-free and/or metal-associated A?? to different extents. Our studies indicate Verbascoside represents a promising structure for further multifunctional tool development against both metal-free A?? and metal-A??.open0

Infection of an Individual with Plague in the Gorno-Altaisk High-Mountain Natural Focus in 2014. Communication 2. Peculiarities of Laboratory Diagnostics and Molecular-Genetic Characterization of the Isolated Strains

Laboratory diagnostics of plague was carried out in compliance with valid operational guidelines and regulations. But its peculiarity consisted in the performance of diagnostic investigations secondary to antimicrobial therapy with application of preparations characterized by the expressed activity towards gram-negative microorganisms, including the agent of plague (ceftriaxone, ciprolet, and amikacin). The studies revealed that under antibiotic treatment during the early phase of infection the most effective method for the laboratory plague diagnostics was PCR. Based on the results of the assay it was possible to establish not only provisional, but also the final diagnosis in a patient. Obtained was genetic characteristics of the strains isolated from the patient and the marmot, withdrawn at the patient’s place, using techniques of molecular-genetic analysis, in particular PCR, multilocus VNTR, and multilocus and genome-wide sequencing. Thereupon the strains were attributed to antique biovar of the main subspecies of plague agent. In addition, close relation to Y. pestis of the main subspecies isolated in the same focus in 2012 and to the strains from Mongolian Altai and Tuvinian mountain focus was determined based on phylogenetic analysis of the isolates