Functional organisation of anterior thoracic stretch receptors in the deep-sea isopod Bathynomus doederleini: Behavioural, morphological and physiological studies

The relationship between segmental mobility and the organisation of thoracic stretch receptors was examined in the deep-sea isopod Bathynomus doederleini, which shows a developed adaptive behaviour during digging. The movements of segments during digging were analysed from video recordings, which showed that a large excursion occurred in the anterior thoracic segments. Dyefills of axons revealed four types of thoracic stretch receptor (TSR): an N-cell type (TSR-1), a differentiated Ncell type (TSR-2), a muscle receptor organ (MRO)-type with a long, single receptor muscle (TSR-3) and an MROtype with a short, single receptor muscle (TSR-4 to TSR-7). Physiologically, TSR-1 and TSR-2 are tonic-type stretch receptors. TSR-3 to TSR-7 show two kinds of stretchactivated responses, a tonic response and a phasico-tonic response in which responses are maintained as long as the stretch stimulus is delivered. Both TSR-2, with a long muscle strand, and TSR-3, with a single, long receptor muscle, have a wide dynamic range in their stretchactivated response. In addition, TSR-2 is controlled by an intersegmental inhibitory reflex from TSR-3. These results suggest that, although TSR-1 has no receptor muscle and TSR-2 has a less-differentiated receptor-like muscle, they are fully functional position detectors of segmental movements, as are the MRO-type receptors TSR-3 to TSR-7.</p

Dynamical system analysis of ignition phenomena using the tangential stretching rate concept

We analyze ignition phenomena by resorting to the stretching rate concept formerly introduced in the study of dynamical systems. We construct a Tangential Stretching Rate (TSR) parameter by combining the concepts of stretching rate with the decomposition of the local tangent space in eigen-modes. The main feature of the TSR is its ability to identify unambiguously the most energetic scale at a given space location and time instant. The TSR depends only on the local composition of the mixture, its temperature and pressure. As such, it can be readily computed during the post processing of computed reactive flow fields, both for spatially homogeneous and in-homogenous systems. Because of the additive nature of the TSR, we defined a normalized participation index measuring the relative contribution of each mode to the TSR. This participation index to the TSR can be combined with the mode amplitude participation Index of a reaction to a mode – as defined in the Computational Singular Perturbation (CSP) method – to obtain a direct link between a reaction and TSR. The reactions having both a large participation index to the TSR and a large CSP mode amplitude participation index are those contributing the most to both the explosive and relaxation regimes of a reactive system. This information can be used for both diagnostics and for the simplification of kinetic mechanisms. We verified the properties of the TSR with reference to three nonlinear planar models (one for isothermal branched-chain reactions, one for a non-isothermal, one-step system, and for non-isothermal branched-chain reactions), to one planar linear model (to discuss issues associated with non-normality), and to test problems involving hydro-carbon oxidation kinetics. We demonstrated that the reciprocal of the TSR parameter is the proper characteristic chemical time scale in problems involving multi-step chemical kinetic mechanisms, because (i) it is the most relevant time scale during both the explosive and relaxation regimes and (ii) it is intrinsic to the kinetics, that is, it can be identified without the need of any ad hoc assumption

On the Performance of Turbo Signal Recovery with Partial DFT Sensing Matrices

This letter is on the performance of the turbo signal recovery (TSR) algorithm for partial discrete Fourier transform (DFT) matrices based compressed sensing. Based on state evolution analysis, we prove that TSR with a partial DFT sensing matrix outperforms the well-known approximate message passing (AMP) algorithm with an independent identically distributed (IID) sensing matrix.Comment: to appear in IEEE Signal Processing Letter

Wireless Information and Energy Transfer for Two-Hop Non-Regenerative MIMO-OFDM Relay Networks

This paper investigates the simultaneous wireless information and energy transfer for the non-regenerative multipleinput multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) relaying system. By considering two practical receiver architectures, we present two protocols, time switchingbased relaying (TSR) and power splitting-based relaying (PSR). To explore the system performance limit, we formulate two optimization problems to maximize the end-to-end achievable information rate with the full channel state information (CSI) assumption. Since both problems are non-convex and have no known solution method, we firstly derive some explicit results by theoretical analysis and then design effective algorithms for them. Numerical results show that the performances of both protocols are greatly affected by the relay position. Specifically, PSR and TSR show very different behaviors to the variation of relay position. The achievable information rate of PSR monotonically decreases when the relay moves from the source towards the destination, but for TSR, the performance is relatively worse when the relay is placed in the middle of the source and the destination. This is the first time to observe such a phenomenon. In addition, it is also shown that PSR always outperforms TSR in such a MIMO-OFDM relaying system. Moreover, the effect of the number of antennas and the number of subcarriers are also discussed.Comment: 16 pages, 12 figures, to appear in IEEE Selected Areas in Communication