7,475 research outputs found

    Direct Methods in High Resolution Electron Microscopy

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    New approaches are proposed to retrieve the wavefunction at the object and from this, to retrieve the projected structure of the object. The wavefunction is retrieved by capturing images at a series of closely spaced focus values and to process the whole 3D data. The structure of the object is retrieved using a formalism based on electron channelling

    Avatars of Eurocentrism in the critique of the liberal peace

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    Recent scholarly critiques of the so-called liberal peace raise important political and ethical challenges to practices of postwar intervention in the global South. However, their conceptual and analytic approaches have tended to reproduce rather than challenge the intellectual Eurocentrism underpinning the liberal peace. Eurocentric features of the critiques include the methodological bypassing of target subjects in research, the analytic bypassing of subjects through frameworks of governmentality, the assumed ontological split between the ‘liberal’ and the ‘local’, and a nostalgia for the liberal subject and the liberal social contract as alternative bases for politics. These collectively produce a ‘paradox of liberalism’ that sees the liberal peace as oppressive but also the only true source of emancipation. However, the article suggests that a repoliticization of colonial difference offers an alternative ‘decolonizing’ approach to critical analysis through repositioning the analytic gaze. Three alternative research strategies for critical analysis are briefly developed

    Spatial variation of the aftershock activity across the Kachchh Rift Basin and its seismotectonic implications

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    We analyzed 3365 relocated aftershocks with magnitude of completeness (Mc) ≄1.7 that occurred in the Kachchh Rift Basin (KRB) between August 2006 and December 2010. The analysis of the new aftershock catalogue has led to improved understanding of the subsurface structure and of the aftershock behaviour. We characterized aftershock behaviour in terms of a-value, b-value, spatial fractal dimension (D s ), and slip ratio (ratio of the slip that occurred on the primary fault and that of the total slip). The estimated b-value is 1.05, which indicates that the earthquake occurred due to active tectonics in the region. The three dimensional b-value mapping shows that a high b-value region is sandwiched around the 2001 Bhuj mainshock hypocenter at depths of 20–25 km between two low b-value zones above and below this depth range. The D s -value was estimated from the double-logarithmic plot of the correlation integral and distance between hypocenters, and is found to be 2.64 ± 0.01, which indicates random spatial distribution beneath the source zone in a two-dimensional plane associated with fluid-filled fractures. A slip ratio of about 0.23 reveals that more slip occurred on secondary fault systems in and around the 2001 Bhuj earhquake (Mw 7.6) source zone in KRB

    Virtual Meeting Rooms: From Observation to Simulation

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    Much working time is spent in meetings and, as a consequence, meetings have become the subject of multidisciplinary research. Virtual Meeting Rooms (VMRs) are 3D virtual replicas of meeting rooms, where various modalities such as speech, gaze, distance, gestures and facial expressions can be controlled. This allows VMRs to be used to improve remote meeting participation, to visualize multimedia data and as an instrument for research into social interaction in meetings. This paper describes how these three uses can be realized in a VMR. We describe the process from observation through annotation to simulation and a model that describes the relations between the annotated features of verbal and non-verbal conversational behavior.\ud As an example of social perception research in the VMR, we describe an experiment to assess human observers’ accuracy for head orientation

    Assessment of heavy metal content in soil and grasslands in national park of the lake plateau of the N. P. “Durmitor” Montenegro

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    Investigations were conducted in the N.P. Durmitor area of Montenegro where anthropogenic activities are negatively impacting forests and grasslands. According to meteorological data, this area has been polluted with heavy metals via aero deposition. The aim of this paper was to present an assessment which describes the content of heavy metals in the top soil layer (0 to 20 cm) and the corresponding vegetation cover. Linear regression was used to explain the relationship between heavy metals in the soils and plants. Statistically significant correlation coefficients were determined between content of heavy metals (Zn, Cu, Pb and Cd) in the soil and plants. Since a statistical significant correlation existed, it was possible to suggest that, increasing the content of heavy metals in the soil will influence an increase in the content of heavy metals in the vegetation cover. Also, transfer factor (TF) values were used to assess the concentrations of elements in plants taken from the soil. The highest transfer factors were obtained for Zn and Cu followed by Cd, with Pb been the least. According to values of TF in the studied conditions, the content of Zn, Cu and Cd were greater in the mobile fractions than in the nonmobile fractions, but the content of Pb was not mobile and available for plants. Thus, we were able to conclude that, soil properties and the form of heavy metals in the soil influence the uptake of heavy metals from the soil by the vegetation cover.Key words: Soil, grassland vegetation, heavy metals, relationship, transfer factor

    Limit on suppression of ionization in metastable neon traps due to long-range anisotropy

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    This paper investigates the possibility of suppressing the ionization rate in a magnetostatic trap of metastable neon atoms by spin-polarizing the atoms. Suppression of the ionization is critical for the possibility of reaching Bose-Einstein condensation with such atoms. We estimate the relevant long-range interactions for the system, consisting of electric quadrupole-quadrupole and dipole-induced dipole terms, and develop short-range potentials based on the Na_2 singlet and triplet potentials. The auto-ionization widths of the system are also calculated. With these ingredients we calculate the ionization rate for spin-polarized and for spin-isotropic samples, caused by anisotropy of the long-range interactions. We find that spin-polarization may allow for four orders of magnitude suppression of the ionization rate for Ne. The results depend sensitively on a precise knowledge of the interaction potentials, however, pointing out the need for experimental input. The same model gives a suppression ratio close to unity for metastable xenon in accordance with experimental results, due to a much increased anisotropy in this case.Comment: 15 pages including figures, LaTex/RevTex, uses epsfig.st

    Porphyry Cu(Mo) deposits of the Urals: insights from molybdenite trace element geochemistry

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    The first data on EMPA and LA-ICPMS study of molybdenite from four porphyry deposits of the South and Middle Urals (Tomino, Mikheevskoe and Benkala porphyry Cu and Talitsa porphyry Mo deposits) are presented. It is shown that most trace elements form mineral inclusions within molybdenite in all the deposits studied; only Re and W are most likely to be incorporated into the molybdenite lattice. Porphyry Cu deposits (Tomino and Mikheevskoe) formed within oceanic arc settings are featured by high contents of Re (mostly over 400 ppm) and low contents of W (<10 ppm) in molybdenite; porphyry Cu deposits from Andean-type geotectonic environment (Benkala) are featured by lower Re content (hundreds ppm) and high contents of W (tens ppm) in molybdenite. Molybdenite from porphyry deposits from collisional setting (Talitsa) has low content of Re and elevated W contents (tens ppm). It is demonstrated that trace element geochemistry of molybdenite is a useful tool to define the source of metal components and the geotectonic environment for porphyry Cu(Mo) deposits.The attached document is the authors’ submitted version of these conference proceedings. You are advised to consult the publisher’s version if you wish to cite from it

    Time-Fractional Optimal Control of Initial Value Problems on Time Scales

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    We investigate Optimal Control Problems (OCP) for fractional systems involving fractional-time derivatives on time scales. The fractional-time derivatives and integrals are considered, on time scales, in the Riemann--Liouville sense. By using the Banach fixed point theorem, sufficient conditions for existence and uniqueness of solution to initial value problems described by fractional order differential equations on time scales are known. Here we consider a fractional OCP with a performance index given as a delta-integral function of both state and control variables, with time evolving on an arbitrarily given time scale. Interpreting the Euler--Lagrange first order optimality condition with an adjoint problem, defined by means of right Riemann--Liouville fractional delta derivatives, we obtain an optimality system for the considered fractional OCP. For that, we first prove new fractional integration by parts formulas on time scales.Comment: This is a preprint of a paper accepted for publication as a book chapter with Springer International Publishing AG. Submitted 23/Jan/2019; revised 27-March-2019; accepted 12-April-2019. arXiv admin note: substantial text overlap with arXiv:1508.0075
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