In this paper we introduce a variant of membrane systems with elementary division and without charges. We allow only elementary division where the resulting membranes are identical; we refer to this using the biological term symmetric division. We prove that this model characterises P. This result characterises the power of a class of membrane systems that fall under the so called P conjecture ...

Stem cell divisions are either asymmetric-in which one daughter cell remains a stem cell and one does not-or symmetric, in which both daughter cells adopt the same fate, either stem or non-stem. Recent studies show that in many tissues operating under homeostatic conditions stem cell division patterns are strongly biased toward the symmetric outcome, raising the question of whether symmetry con...

Let $G*H$ be the product $*$ of $G$ and $H$. In this paper we determine the rth power of the graph $G*H$ in terms of $G^r, H^r$ and $G^r*H^r$, when $*$ is the join, Cartesian, symmetric difference, disjunctive, composition, skew and corona product. Then we solve the equation $(G*H)^r=G^r*H^r$. We also compute the Wiener index and Wiener polarity index of the skew product.

Orthogonal frequency division multiplexing with index modulation (OFDM-IM), stands out among conventional communication technologies, as it uses the indices of available transmit entities. Thanks to such an approach, offers a novel method for transmission extra data bits. Recent years have seen great interest in chaos-based communications. The spectrum-spreading signals used chaotic signal tech...

Using long-term, time-lapse video-microscopy, we investigated how single progenitor cells isolated from the early embryonic cerebral cortex produce neurons and glia over time. Clones of 10 cells or less were produced by short symmetric or asymmetric division patterns, commonly terminating in a 'pair progenitor' for two morphologically identical neurons. Larger trees were composites of these sho...