1,835 research outputs found

    Petrographic and crystallographic study of silicate minerals in lunar rocks

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    Optical U-stage measurements, chemical microprobe data, and X-ray procession photographs of a bytownite twin group from rock 12032,44 are compared. Sharp but weak b and no c-reflections were observed for this An89 bytownite indicating a partly disordered structure. Euler angles, used to characterize the orientation of the optical indicatrix, compare better with values for plutonic than for volcanic plagioclase. This indicates that structural and optical properties cannot be directly correlated

    The UK’s emerging regulatory framework for point-of-care manufacture: insights from a workshop on advanced therapies

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    Point-of-care (POC) manufacture can be defined as the production of therapies in clinical settings or units close to hospitals and patients. This approach is becoming increasingly via- ble due to the emergence of flexible manufacturing technologies. Expecting an increase in this kind of production, the UK’s regulatory agency, the Medicines and Healthcare products Regulatory Agency (MHRA) is proposing a regulatory framework specifically designed for POC manufacture. To discuss the challenges of POC manufacture and the MHRA’s pro- posal, the EPSRC Future Targeted Healthcare Manufacturing Hub (FTHMH) organized a workshop drawing insights from specialists in cell and gene therapy manufacture. Through presentations and discussion roundtables, the workshop highlighted the challenges for the UK and other countries implementing POC manufacture. The workshop attendees stressed four main issues: quality control; standardization and equipment use; availability of qualified personnel; and the challenges to be met by hospitals participating in POC manufacture systems. This commentary provides a summary of the points discussed in this workshop

    Material studies related to lunar surface exploration. Volume 1 - Lunar soil mechanics and soil properties Final report, 6 Mar. 1967 - 30 Jun. 1968

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    Lunar soil mechanics and properties for structural engineering aspects of lunar spacecraft landings and surface exploratio

    Noise gates for decoherent quantum circuits

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    A major problem in exploiting microscopic systems for developing a new technology based on the principles of Quantum Information is the influence of noise which tends to work against the quantum features of such systems. It becomes then crucial to understand how noise affects the evolution of quantum circuits: several techniques have been proposed among which stochastic differential equations (SDEs) can represent a very convenient tool. We show how SDEs naturally map any Markovian noise into a linear operator, which we will call a noise gate, acting on the wave function describing the state of the circuit, and we will discuss some examples. We shall see that these gates can be manipulated like any standard quantum gate, thus simplifying in certain circumstances the task of computing the overall effect of the noise at each stage of the protocol. This approach yields equivalent results to those derived from the Lindblad equation; yet, as we show, it represents a handy and fast tool for performing computations, and moreover, it allows for fast numerical simulations and generalizations to non Markovian noise. In detail we review the depolarizing channel and the generalized amplitude damping channel in terms of this noise gate formalism and show how these techniques can be applied to any quantum circuit.Comment: 10 pages, 4 figures: journal reference added + some typos correcte

    Assessment of a quantum phase gate operation based on nonlinear optics

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    We analyze in detail the proposal for a two-qubit gate for travelling single-photon qubits recently presented by C. Ottaviani \emph{et al}. [Phys. Rev. A \textbf{73}, 010301(R) (2006)]. The scheme is based on an ensemble of five-level atoms coupled to two quantum and two classical light fields. The two quantum fields undergo cross-phase modulation induced by electromagnetically induced transparency. The performance of this two-qubit quantum phase gate for travelling single-photon qubits is thoroughly examined in the steady-state and transient regimes, by means of a full quantum treatment of the system dynamics. In the steady-state regime, we find a general trade-off between the size of the conditional phase shift and the fidelity of the gate operation. However, this trade-off can be bypassed in the transient regime, where a satisfactory gate operation is found to be possible, significantly reducing the gate operation time.Comment: 12 pages, 15 figure

    The thermodynamic dual structure of linear-dissipative driven systems

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    The spontaneous emergence of dynamical order, such as persistent currents, is sometimes argued to require principles beyond the entropy maximization of the second law of thermodynamics. I show that, for linear dissipation in the Onsager regime, current formation can be driven by exactly the Jaynesian principle of entropy maximization, suitably formulated for extended systems and nonequilibrium boundary conditions. The Legendre dual structure of equilibrium thermodynamics is also preserved, though it requires the admission of current-valued state variables, and their correct incorporation in the entropy

    Localization of the SFT inspired Nonlocal Linear Models and Exact Solutions

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    A general class of gravitational models driven by a nonlocal scalar field with a linear or quadratic potential is considered. We study the action with an arbitrary analytic function F(â–ˇ)F(\Box), which has both simple and double roots. The way of localization of nonlocal Einstein equations is generalized on models with linear potentials. Exact solutions in the Friedmann-Robertson-Walker and Bianchi I metrics are presented.Comment: 20 pages, 3 figures, published in the proceedings of the VIII International Workshop "Supersymmetries and Quantum Symmetries" (SQS'09), Dubna, Russia, July 29 - August 3, 2009, http://theor.jinr.ru/~sqs09
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