3,646 research outputs found

    Improving the Functional Control of Aged Ferroelectrics using Insights from Atomistic Modelling

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    We provide a fundamental insight into the microscopic mechanisms of the ageing processes. Using large scale molecular dynamics simulations of the prototypical ferroelectric material PbTiO3, we demonstrate that the experimentally observed ageing phenomena can be reproduced from intrinsic interactions of defect-dipoles related to dopant-vacancy associates, even in the absence of extrinsic effects. We show that variation of the dopant concentration modifies the material's hysteretic response. We identify a universal method to reduce loss and tune the electromechanical properties of inexpensive ceramics for efficient technologies.Comment: 6 pages, 3 figure

    Josephson Coupling through a Quantum Dot

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    We derive, via fourth order perturbation theory, an expression for the Josephson current through a gated interacting quantum dot. We analyze our expression for two different models of the superconductor-dot-superconductor (SDS) system. When the matrix elements connecting dot and leads are featureless constants, we compute the Josephson coupling J_c as a function of the gate voltage and Coulomb interaction. In the diffusive dot limit, we compute the probability distribution P(J_c) of Josephson couplings. In both cases, pi junction behavior (J_c < 0) is possible, and is not simply dependent on the parity of the dot occupancy.Comment: 9 pages; 3 encapsulated PostScript figure

    Random tree growth by vertex splitting

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    We study a model of growing planar tree graphs where in each time step we separate the tree into two components by splitting a vertex and then connect the two pieces by inserting a new link between the daughter vertices. This model generalises the preferential attachment model and Ford's α\alpha-model for phylogenetic trees. We develop a mean field theory for the vertex degree distribution, prove that the mean field theory is exact in some special cases and check that it agrees with numerical simulations in general. We calculate various correlation functions and show that the intrinsic Hausdorff dimension can vary from one to infinity, depending on the parameters of the model.Comment: 47 page

    An analysis of integrative outcomes in the Dayton peace negotiations

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    The nature of the negotiated outcomes of the eight issues of the Dayton Peace Agreement was studied in terms of their integrative and distributive aspects. in cases where integrative elements were Sound, further analysis was conducted by concentrating on Pruitt's five types of integrative solutions: expanding the pie, cost cutting, non-specific compensation, logrolling, and bridging. The results showed that real world international negotiations can arrive at integrative agreements even when they involve redistribution of resources tin this case the redistribution of former Yugoslavia). Another conclusion was that an agreement can consist of several distributive outcomes and several integrative outcomes produced by different kinds of mechanisms. Similarly, in single issues more than one mechanism can be used simultaneously. Some distributive bargaining was needed in order to determine how much compensation was required. Finally, each integrative formula had some distributive aspects as well

    The magnitude of educational disadvantage amongst indigenous minority groups in Australia.

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    Indigenous groups are amongst the most disadvantaged minority groups in the developed world. This paper examines the educational disadvantage of indigenous Australians by assessing academic performance at a relatively early age. We find that, by the age of 10, indigenous Australians are substantially behind non-indigenous Australians in academic achievement. Their relative performance deteriorates further over the next 2 years. School and locality do not appear to be important determinants of the indigenous to non-indigenous achievement gap. However, geographic remoteness, indigenous ethnicity and language use at home have a marked influence on educational achievement. A current focus of Australian indigenous policy is to increase school resources. Our results suggest that this will not eliminate indigenous educational disadvantage on its own

    A law of large numbers approximation for Markov population processes with countably many types

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    When modelling metapopulation dynamics, the influence of a single patch on the metapopulation depends on the number of individuals in the patch. Since the population size has no natural upper limit, this leads to systems in which there are countably infinitely many possible types of individual. Analogous considerations apply in the transmission of parasitic diseases. In this paper, we prove a law of large numbers for rather general systems of this kind, together with a rather sharp bound on the rate of convergence in an appropriately chosen weighted 1\ell_1 norm.Comment: revised version in response to referee comments, 34 page

    Level Set Segmentation with Shape and Appearance Models Using Affine Moment Descriptors

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    We propose a level set based variational approach that incorporates shape priors into edge-based and region-based models. The evolution of the active contour depends on local and global information. It has been implemented using an efficient narrow band technique. For each boundary pixel we calculate its dynamic according to its gray level, the neighborhood and geometric properties established by training shapes. We also propose a criterion for shape aligning based on affine transformation using an image normalization procedure. Finally, we illustrate the benefits of the our approach on the liver segmentation from CT images

    Transduction by Phi Bb-1, a Bacteriophage of Borrelia Burgdorferi

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    We previously described a bacteriophage of the Lyme disease agent Borrelia burgdorferi designated phi BB-1. This phage packages the host complement of the 32-kb circular plasmids (cp32s), a group of homologous molecules found throughout the genus Borrelia. To demonstrate the ability of phi BB-1 to package and transduce DNA, a kanamycin resistance cassette was inserted into a cloned fragment of phage DNA, and the resulting construct was transformed into B. burgdorferi CA-11.2A cells. The kan cassette recombined into a resident cp32 and was stably maintained. The cp32 containing the kan cassette was packaged by phi BB-1 released from this B. burgdorferi strain. phi BB-1 has been used to transduce this antibiotic resistance marker into naive CA-11.2A cells, as well as two other strains of B. burgdorferi. This is the first direct evidence of a mechanism for lateral gene transfer in B. burgdorferi

    Pengantar Akuntansi Buku 1 -7/E.

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    PENGANTAR AKUNTANSI BUKU 1 -7/E. Materi Buku Pengantar Akuntansi Edisi 7 ini merupakan salah satu buku teks terbaik yang membahas berbagai konsep dasar akuntansi keuangan, yang dimulai dari siklus akuntansi untuk perusahaan jasa, siklus akuntansi untuk perusahaan dagang, dan perlakuan akuntansi untuk akun-akun utama perusahaan seperti kas, piutang, kewajiban, investasi, dan lain-lain. Buku ini dilengkapi dengan contoh dan kasus perusahaan nyata yang ditampilkan dalam Kotak Wawasan Etika, Wawasan e-Business, dan Wawasan Internasional. Laporan keuangan dan perusahaan terkemuka, yaitu PepsiCo dan Coca-Cola Company dilampirkan pada bagian akhir untuk memberikan gambaran kepada pembaca mengenai hasil akhir proses akuntansi yang dibahas. Selain itu, latihan dan soal yang beragam akan membantu para pembaca untuk semakin memahami konsep-konsep akuntansi yang dijelaskan. Buku ini ditujukan bagi mahasiswa yang mengambil mata kuliah Pengantar Akuntansi maupun bagi siapa saja yang ingin mengenal dan bermaksud mendapatkan pemahaman dasar akuntansi. Daftar Isi Bab 1 Penerapan Akuntansi Bab 2 Proses Pencatatan Bab 3 Penyesuaian Akun Bab 4 Penyelesaian Siklus Akuntansi Bab 5 Akuntansi untuk Perusahaan Dagang Bab 6 Persediaan Bab 7 Sistem Informasi Akuntansi Bab 8 Pengendalian Internal dan Kas Bab 9 Akuntansi untuk Piutang Bab 10 Aset Tetap, Sumber Daya Alam, dan Aset Tidak Berwujud
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