1,831 research outputs found

    Red Golem: Criticism of Industrial Civilization in Soviet Culture and Misticism During the Civil War

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    This article describes an early Soviet version of the critique of the industrial culture, based on the works by Alexander Bogdanov and George Gurdjieff. Bogdanov’s analysis of Taylorism is explored within the context of the development of the concept of ‘proletarian culture’. Terminological apparatus of George Gurdjieff’s theory is described as a form of radical criticism of the early XXth-century culture. We also highlight the place of the ‘man-machine’ metaphor within the intellectual life of the post-revolutionary Soviet Russia.     Keywords: Taylorism, Soviet culture, 1919, А. Bogdanov, proletarian culture, G. Gurdjief

    Essential spectra and exponential estimates of eigenfunctions of lattice operators of quantum mechanics

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    This paper is devoted to estimates of the exponential decay of eigenfunctions of difference operators on the lattice Z^n which are discrete analogs of the Schr\"{o}dinger, Dirac and square-root Klein-Gordon operators. Our investigation of the essential spectra and the exponential decay of eigenfunctions of the discrete spectra is based on the calculus of so-called pseudodifference operators (i.e., pseudodifferential operators on the group Z^n) with analytic symbols and on the limit operators method. We obtain a description of the location of the essential spectra and estimates of the eigenfunctions of the discrete spectra of the main lattice operators of quantum mechanics, namely: matrix Schr\"{o}dinger operators on Z^n, Dirac operators on Z^3, and square root Klein-Gordon operators on Z^n

    Liberty, Equality and Not Too Much Fraternity: An Experience in Practical Application of Liberal Education Teaching Techniques

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    The paper explores an experience in practical application of liberal education teaching techniques. We describe the most frequently used techniques and present sample classroom assignments based on this framework. We also discuss the opportunities and limitations provided by the use of these methods in a classroom setting. Keywords: teaching techniques, liberal education, writing and analytical reading, humanities teaching

    Pattern formation without heating in an evaporative convection experiment

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    We present an evaporation experiment in a single fluid layer. When latent heat associated to the evaporation is large enough, the heat flow through the free surface of the layer generates temperature gradients that can destabilize the conductive motionless state giving rise to convective cellular structures without any external heating. The sequence of convective patterns obtained here without heating, is similar to that obtained in B\'enard-Marangoni convection. This work present the sequence of spatial bifurcations as a function of the layer depth. The transition between square to hexagonal pattern, known from non-evaporative experiments, is obtained here with a similar change in wavelength.Comment: Submitted to Europhysics Letter

    Essential spectra of difference operators on \sZ^n-periodic graphs

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    Let (\cX, \rho) be a discrete metric space. We suppose that the group \sZ^n acts freely on XX and that the number of orbits of XX with respect to this action is finite. Then we call XX a \sZ^n-periodic discrete metric space. We examine the Fredholm property and essential spectra of band-dominated operators on lp(X)l^p(X) where XX is a \sZ^n-periodic discrete metric space. Our approach is based on the theory of band-dominated operators on \sZ^n and their limit operators. In case XX is the set of vertices of a combinatorial graph, the graph structure defines a Schr\"{o}dinger operator on lp(X)l^p(X) in a natural way. We illustrate our approach by determining the essential spectra of Schr\"{o}dinger operators with slowly oscillating potential both on zig-zag and on hexagonal graphs, the latter being related to nano-structures

    Possibility of measuring the thermal Casimir interaction between a plate and a cylinder attached to a micromachined oscillator

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    We investigate the possibility of measuring the thermal Casimir force and its gradient in the configuration of a plate and a microfabricated cylinder attached to a micromachined oscillator. The Lifshitz-type formulas in this configuration are derived using the proximity force approximation. The accuracy for the obtained expressions is determined from a comparison with exact results available in ideal metal case. Computations of the thermal correction to both the Casimir force and its gradient are performed in the framework of different theoretical approaches proposed in the literature. The correction to the Casimir force and its gradient due to lack of parallelism of the plate and cylinder is determined using the nonmultiplicative approach. The error introduced in the theory due to the finite length of the cylinder is estimated. We propose that both static and dynamic experiments measuring the thermal Casimir interaction between a cylinder and a plate using a micromachined oscillator can shed additional light on the thermal Casimir force problem. Specifically, it is shown that the static experiment is better adapted for the measurement of thermal effects.Comment: 29 pages, 4 figures, 1 table; minor additions are made in accordance to the version accepted for publication; to appear in Phys. Rev.

    A Simple Theory of Condensation

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    A simple assumption of an emergence in gas of small atomic clusters consisting of cc particles each, leads to a phase separation (first order transition). It reveals itself by an emergence of ``forbidden'' density range starting at a certain temperature. Defining this latter value as the critical temperature predicts existence of an interval with anomalous heat capacity behaviour cpΔT1/cc_p\propto\Delta T^{-1/c}. The value c=13c=13 suggested in literature yields the heat capacity exponent α=0.077\alpha=0.077.Comment: 9 pages, 1 figur

    The impact of climate change on the geographical distribution of two vectors of Chagas disease: Implications for the force of infection

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    Chagas disease, caused by the parasite Trypanosoma cruzi, is the most important vector-borne disease in Latin America. The vectors are insects belonging to the Triatominae (Hemiptera, Reduviidae), and are widely distributed in the Americas. Here, we assess the implications of climatic projections for 2050 on the geographical footprint of two of the main Chagas disease vectors: Rhodnius prolixus (tropical species) and Triatoma infestans (temperate species).We estimated the epidemiological implications of current to future transitions in the climatic niche in terms of changes in the force of infection (FOI) on the rural population of two countries: Venezuela (tropical) and Argentina (temperate). The climatic projections for 2050 showed heterogeneous impact on the climatic niches of both vector species, with a decreasing trend of suitability of areas that are currently at high-to-moderate transmission risk. Consequently, climatic projections affected differently the FOI for Chagas disease in Venezuela and Argentina. Despite the heterogeneous results, our main conclusions point out a decreasing trend in the number of new cases of Tr. cruzi human infections per year between current and future conditions using a climatic niche approach.Centro de Estudios Parasitológicos y de VectoresFacultad de Ciencias Naturales y Muse
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