8,677 research outputs found

    Entanglement and the Thermodynamic Arrow of Time

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    We discuss quantum entanglement in the context of the thermodynamic arrow of time. We review the role of correlations in entropy-decreasing events and prove that the occurrence of a transformation between two thermodynamic states constitutes a new type of entanglement witness, one not defined as a separating plane in state space between separable and entangled states, but as a physical process dependent on the local initial properties of the states. Extending work by Partovi, we consider a general entangled multipartite system that allows large reversals of the thermodynamic arrow of time. We describe a hierarchy of arrows that arises from the different correlations allowed in a quantum state and examine these features in the context of Maxwell's Demon. We examine in detail the case of three qubits, and also propose some simple experimental demonstrations possible with small numbers of qubits.Comment: 10 pages with 9 figure

    Tournaisian brachiopods from Baywulla, Queensland

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    Excess Vibrational Modes and the Boson Peak in Model Glasses

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    The excess low-frequency normal modes for two widely-used models of glasses were studied at zero temperature. The onset frequencies for the anomalous modes for both systems agree well with predictions of a variational argument, which is based on analyzing the vibrational energy originating from the excess contacts per particle over the minimum number needed for mechanical stability. Even though both glasses studied have a high coordination number, most of the additional contacts can be considered to be weak.Comment: 4 pages, 3 figures, submitted to Physical Review Letter

    Hypoxia and oxidative stress in breast cancer: Hypoxia signalling pathways

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    Hypoxia-inducible factor-1 (HIF), which is centrally involved in physiological oxygen homeostasis, is also activated in the majority of tumours. Activation of HIF can occur through genetic mechanisms or as a result of hypoxia within the tumour microenvironment. In some cases HIF activation appears to be intimately linked to the proliferative stimulus itself. HIF affects patterns of gene expression and tumour growth, although precise effects vary between tumour types. Modulation of HIF activity, if correctly applied, may be therapeutically beneficial in tumour therapy

    Supporting Primary and Secondary Beginning Teachers Online: Key findings of the Education Alumni Support Project

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    During 2005, the Education Alumni Support Project (EdASP) (Maxwell, Smith, Baxter, Boyd, Harrington, Jenkins, Sargeant & Tamatea 2006) provided online support for University of New England (UNE) graduand, and later, graduate, teachers as they commenced their careers. The project was based on research which reported that many beginning teachers did not get the support they needed as permanent or contract workers, or, as casual, relief or support teachers, and that small scale trials had shown that online support could be effective. One third of beginning teachers who were alumni of UNE in 2004, reported they did not receive adequate or any mentoring. UNE web-based technologies provided the teachers and mentors with online environments for professional and social interaction, and resource sharing. We found that support was especially sought by the project participants in their first school term, and there were differences in the levels of online support sought by secondary and primary beginning teachers. The project raises implications for on-going systemic support for beginning teachers, the issue of transition from students to teachers, as well as questions about teacher education students’ preparation. This paper provides the key findings of the project. Detailed description of the project structure, data collection and data analysis are available in Maxwell et al. (2006)

    Comment on "Plasma ionization by annularly bounded helicon waves" [Phys . Plasmas 13, 063501 (2006)]

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    The neoclassical calculation of the helicon wave theory contains a fundamental flaw. Use is made of a proportional relationship between the magnetic field and its curl to derive the Helmholtz equation describing helicon wave propagation; however, by the fundamental theorem of Stokes, the curl of the magnetic field must be perpendicular to that portion of the field contributing to the local curl. Reexamination of the equations of motion indicates that only electromagnetic waves propagate through a stationary region of constant pressure in a fully ionized, neutral medium.Comment: 7 pages, 1 figure, to be published in Phys. Plasmas, http://link.aip.org/link/?PHPAEN/16/054701/
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