Evaluating the number of active flows in a scheduler realizing fair statistical bandwidth sharing

Politecnico di Torino ‡ Despite its well-known advantages, per-flow fair queueing has not been deployed in the Internet mainly because of the common belief that such scheduling is not scalable. The objective of the present paper is to demonstrate using trace simulations and analytical evaluations that this belief is misguided. We show that although the number of flows in progress increases with link speed, the number that needs scheduling at any moment is largely independent of this rate. The number of such active flows is a random process typically measured in hundreds even though there may be tens of thousands of flows in progress. The simulations are performed using traces from commercial and research networks with quite different traffic characteristics. Analysis is based on models for balanced fair statistical bandwidth sharing and applies properties of queue busy periods to explain the observed behaviour

The laminar position, morphology, and gene expression profiles of cortical astrocytes are influenced by time of birth from ventricular/subventricular progenitors.

Astrocytes that reside in superficial (SL) and deep cortical layers have distinct molecular profiles and morphologies, which may underlie specific functions. Here, we demonstrate that the production of SL and deep layer (DL) astrocyte populations from neural progenitor cells in the mouse is temporally regulated. Lineage tracking following in utero and postnatal electroporation with PiggyBac (PB) EGFP and birth dating with EdU and FlashTag, showed that apical progenitors produce astrocytes during late embryogenesis (E16.5) that are biased to the SL, while postnatally labeled (P0) astrocytes are biased to the DL. In contrast, astrocytes born during the predominantly neurogenic window (E14.5) showed a random distribution in the SL and DL. Of interest, E13.5 astrocytes birth dated at E13.5 with EdU showed a lower layer bias, while FT labeling of apical progenitors showed no bias. Finally, examination of the morphologies of "biased" E16.5- and P0-labeled astrocytes demonstrated that E16.5-labeled astrocytes exhibit different morphologies in different layers, while P0-labeled astrocytes do not. Differences based on time of birth are also observed in the molecular profiles of E16.5 versus P0-labeled astrocytes. Altogether, these results suggest that the morphological, molecular, and positional diversity of cortical astrocytes is related to their time of birth from ventricular/subventricular zone progenitors

The Key Factor to Adventist Church Growth

Seminar presented at the Natural Church Development Training. Riga, Latvi