12,988 research outputs found
World History, the Social Sciences, and the Dynamics of Contemporary Global Politics
This article argues that the discipline of world history, with its interdisciplinary ties to the social sciences and its incorporation of the cultural insights of recent historiography, makes an ideal tool for conveying the complexities of the contemporary world in a “user-friendly” way. It argues further that one particular global structural analysis, from the author’s world history textbook Frameworks of World History, exposes a deep pattern that helps explain many of the central conflicts in contemporary global politics. By highlighting the tension that has existed between individual communities, or hierarchies, and the networks that connected those communities, a tension going back as far as the modern human species, the article exposes the deep roots of the central conflict between today’s global network and its cultural value of capitalism on the one hand, and modern hierarchies and their central value of nationalism on the other. The cultural aspect of this analysis offers a possible route forward from the problems and repressive politics that flow from this central conflict
Density functional study of copper segregation in aluminum
The structural and electronic properties of Cu segregation in aluminum are studied in the framework of the density functional theory, within the projector augmented plane-wave method and both its local density approximation (LDA) and generalized gradient approximation (GGA). We first studied Al–Cu interactions in bulk phase at low copper concentration (≤3.12%: at). We conclude to a tendency to the formation of a solid solution at T=0 K. We moreover investigated surface alloy properties for varying compositions of a Cu doped Al layer in the (111) Al surface then buried in an (111) Al slab. Calculated segregation energies show unstable systems when Cu atoms are in the surface position (position 1). In the absence of ordering effects for Cu atoms in a layer (xCu=1/9 and xCu=1/3), the system is more stable when the doped layer is buried one layer under the surface (position 2), whereas for xCu=1/2 to xCu=1 (full monolayer), the doped layer is more accommodated when buried in the sub-sub-surface (position 3). First stage formation of GP1- and GP2-zones was finally modeled by doping (100) Al layers with Cu clusters in a (111) Al slab, in the surface then buried one and two layers under the surface. These multilayer clusters are more stable when buried one layer beneath the surface. Systems modeling GP1-zones are more stable than systems modeling GP2-zones. However the segregation of a full copper (100) monolayer in an (100) Al matrix shows a copper segregation deep in the bulk with a segregation barrier. Our results fit clearly into a picture of energetics and geometrical properties dominated by preferential tendency to Cu clustering close to the (111) Al surface
Lattice-Based proof of a shuffle
In this paper we present the first fully post-quantum proof of a shuffle for RLWE encryption schemes. Shuffles are commonly used to construct mixing networks (mix-nets), a key element to ensure anonymity in many applications such as electronic voting systems. They should preserve anonymity even against an attack using quantum computers in order to guarantee long-term privacy. The proof presented in this paper is built over RLWE commitments which are perfectly binding and computationally hiding under the RLWE assumption, thus achieving security in a post-quantum scenario. Furthermore we provide a new definition for a secure mixing node (mix-node) and prove that our construction satisfies this definition.Peer ReviewedPostprint (author's final draft
Statistics of work and fluctuation theorems for microcanonical initial states
The work performed on a system in a microcanonical state by changes in a
control parameter is characterized in terms of its statistics. The transition
probabilities between eigenstates of the system Hamiltonians at the beginning
and the end of the parameter change obey a detailed balance-like relation from
which various forms of the microcanonical fluctuation theorem are obtained. As
an example, sudden deformations of a two dimensional harmonic oscillator
potential are considered and the validity of the microcanonical Jarzynski
equality connecting the degrees of degeneracy of energy eigenvalues before and
after the control parameter change is confirmed.Comment: 16 pages, 5 figure
Automated Home Oxygen Delivery for Patients with COPD and Respiratory Failure: A New Approach
Long-term oxygen therapy (LTOT) has become standard care for the treatment of patients with chronic obstructive pulmonary disease (COPD) and other severe hypoxemic lung diseases. The use of new portable O-2 concentrators (POC) in LTOT is being expanded. However, the issue of oxygen titration is not always properly addressed, since POCs rely on proper use by patients. The robustness of algorithms and the limited reliability of current oximetry sensors are hindering the effectiveness of new approaches to closed-loop POCs based on the feedback of blood oxygen saturation. In this study, a novel intelligent portable oxygen concentrator (iPOC) is described. The presented iPOC is capable of adjusting the O-2 flow automatically by real-time classifying the intensity of a patient's physical activity (PA). It was designed with a group of patients with COPD and stable chronic respiratory failure. The technical pilot test showed a weighted accuracy of 91.1% in updating the O-2 flow automatically according to medical prescriptions, and a general improvement in oxygenation compared to conventional POCs. In addition, the usability achieved was high, which indicated a significant degree of user satisfaction. This iPOC may have important benefits, including improved oxygenation, increased compliance with therapy recommendations, and the promotion of PA
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