16,805 research outputs found

    Exploring the possibility of following the movements of a bird from an artificial earth satellite

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    The development of a harness to hold the transmitter is discussed along with satellite systems for monitoring the flight paths of the birds, and incorporating biological information into the tracking signal

    Interaction of two systems with saddle-node bifurcations on invariant circles. I. Foundations and the mutualistic case

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    The saddle-node bifurcation on an invariant circle (SNIC) is one of the codimension-one routes to creation or destruction of a periodic orbit in a continuous-time dynamical system. It governs the transition from resting behaviour to periodic spiking in many class I neurons, for example. Here, as a first step towards theory of networks of such units the effect of weak coupling between two systems with a SNIC is analysed. Two crucial parameters of the coupling are identified, which we call \delta_1 and \delta_2. Global bifurcation diagrams are obtained here for the "mutualistic" case \delta_1 \delta_2 > 0. According to the parameter regime, there may coexist resting and periodic attractors, and there can be quasiperiodic attractors of torus or cantorus type, making the behaviour of even such a simple system quite non-trivial. In a second paper we will analyse the mixed case \delta_1 \delta_2 < 0 and summarise the conclusions of this study.Comment: 37 pages, 27 figure

    On chemiluminescent emission from an infiltrated chiral sculptured thin film

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    The theory describing the far-field emission from a dipole source embedded inside a chiral sculptured thin film (CSTF), based on a spectral Green function formalism, was further developed to allow for infiltration of the void regions of the CSTF by a fluid. In doing so, the extended Bruggeman homogenization formalism--which accommodates constituent particles that are small compared to wavelength but not vanishingly small--was used to estimate the relative permittivity parameters of the infiltrated CSTF. For a numerical example, we found that left circularly polarized (LCP) light was preferentially emitted through one face of the CSTF while right circularly polarized (RCP) light was preferentially emitted through the opposite face, at wavelengths within the Bragg regime. The centre wavelength for the preferential emission of LCP/RCP light was red shifted as the refractive index of the infiltrating fluid increased from unity, and this red shift was accentuated when the size of the constituent particles in our homogenization model was increased. Also, the bandwidth of the preferential LCP/RCP emission regime decreased as the refractive index of the infiltrating fluid increased from unity

    Inward foreign direct investment and constitutional change in Scotland

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    Purpose - To undertake an analysis of the implications of potential Scottish independence for inward foreign direct investment (FDI), multinational enterprise strategies, and the local economy.&lt;p&gt;&lt;/p&gt; Design/methodology/approach - Takes a multidisciplinary approach drawing upon literature and evidence in the international business and management, political economy, and economic geography fields to analyze the role and impact of inward FDI in Scotland following possible Scottish independence.&lt;p&gt;&lt;/p&gt; Findings - Scotland continues as an attractive location for FDI, with greater diversity than hitherto. While the country’s comparative advantages in immobile natural resources provide some protection from uncertainty, weak embeddedness is a risk factor irrespective of independence. A range of transition costs of independence are identified, which could be high and of indeterminate duration, and some will be sector-specific. There are also new possibilities for tailoring of policies, and potential reindustrialization opportunities in renewable technologies. The foreign investors most vulnerable to political risks and uncertainties are those whose market scope is the rest of the UK (rUK) either as exporters or value chain integrators, in addition to the high political risk industries of energy, banking, and financial services and defence. Scottish subsidiaries’ significance within their parent MNE groups will also be a major factor in determining responses to political risks and uncertainties.&lt;p&gt;&lt;/p&gt; Originality/value - Specific focus upon the impact of potential independence on the foreign-owned sector as a major contributor to the Scottish economy.&lt;p&gt;&lt;/p&gt

    Diffusion and convection of gaseous and fine particulate from a chimney

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    Particle dispersion from a high chimney is considered and an expression for the subsequent concentration of the particulate deposited on the ground is derived. We consider the general case wherein the effects of both diffusion and convection on the steady state ground concentration of particulate are incorporated. Two key parameters emerge from this analysis: the ratio of diffusion to convection and the nondimensionalised surface mass transfer rate. We also solve the inverse problem of recovering these two parameters given the boundary concentration profile and provide an estimate of the concentration flux above the chimney stack
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