Antiphase Synchronization in a Flagellar-Dominance Mutant of Chlamydomonas

Groups of beating flagella or cilia often synchronize so that neighboring filaments have identical frequencies and phases. A prime example is provided by the unicellular biflagellate Chlamydomonas reinhardtii, which typically displays synchronous in-phase beating in a low-Reynolds number version of breaststroke swimming. We report here the discovery that ptx1, a flagellar dominance mutant of C. reinhardtii, can exhibit synchronization in precise antiphase, as in the freestyle swimming stroke. Long-duration high-speed imaging shows that ptx1 flagella switch stochastically between in-phase and antiphase states, and that the latter has a distinct waveform and significantly higher frequency, both of which are strikingly similar to those found during phase slips that stochastically interrupt in-phase beating of the wildtype. Possible mechanisms underlying these observations are discussed.Comment: 5 pages, 4 figure

Rotavirus vaccines contribute towards universal health coverage in a mixed public-private healthcare system.

OBJECTIVES: To evaluate rotavirus vaccination in Malaysia from the household's perspective. The extended cost-effectiveness analysis (ECEA) framework quantifies the broader value of universal vaccination starting with non-health benefits such as financial risk protection and equity. These dimensions better enable decision-makers to evaluate policy on the public finance of health programmes. METHODS: The incidence, health service utilisation and household expenditure related to rotavirus gastroenteritis according to national income quintiles were obtained from local data sources. Multiple birth cohorts were distributed into income quintiles and followed from birth over the first five years of life in a multicohort, static model. RESULTS: We found that the rich pay more out of pocket (OOP) than the poor, as the rich use more expensive private care. OOP payments among the poorest although small are high as a proportion of household income. Rotavirus vaccination results in substantial reduction in rotavirus episodes and expenditure and provides financial risk protection to all income groups. Poverty reduction benefits are concentrated amongst the poorest two income quintiles. CONCLUSION: We propose that universal vaccination complements health financing reforms in strengthening Universal Health Coverage (UHC). ECEA provides an important tool to understand the implications of vaccination for UHC, beyond traditional considerations of economic efficiency

Coordinated beating of algal flagella is mediated by basal coupling.

Cilia and flagella often exhibit synchronized behavior; this includes phase locking, as seen in Chlamydomonas, and metachronal wave formation in the respiratory cilia of higher organisms. Since the observations by Gray and Rothschild of phase synchrony of nearby swimming spermatozoa, it has been a working hypothesis that synchrony arises from hydrodynamic interactions between beating filaments. Recent work on the dynamics of physically separated pairs of flagella isolated from the multicellular alga Volvox has shown that hydrodynamic coupling alone is sufficient to produce synchrony. However, the situation is more complex in unicellular organisms bearing few flagella. We show that flagella of Chlamydomonas mutants deficient in filamentary connections between basal bodies display markedly different synchronization from the wild type. We perform micromanipulation on configurations of flagella and conclude that a mechanism, internal to the cell, must provide an additional flagellar coupling. In naturally occurring species with 4, 8, or even 16 flagella, we find diverse symmetries of basal body positioning and of the flagellar apparatus that are coincident with specific gaits of flagellar actuation, suggesting that it is a competition between intracellular coupling and hydrodynamic interactions that ultimately determines the precise form of flagellar coordination in unicellular algae.This work is supported by a Junior Research Fellowship from Magdalene College Cambridge (KYW) and a Wellcome Trust Senior Investigator Award (REG). We thank Kyriacos Leptos and Marco Polin for discussions relating to the contractility of the basal apparatus at an early stage of this work, and the possible insights provided by the vfl class of mutants, Francois Peaudecerf for kindly providing the CR gametes, Matthew Herron, Thomas Proschold and Stephanie Hohn for valuable comments on the manuscript.This is the author accepted manuscript. It is currently under an indefinite embargo pending publication by the National Academy of Sciences

Antiphase synchronization in a flagellar-dominance mutant of Chlamydomonas

Groups of beating flagella or cilia often synchronize so that neighboring filaments have identical frequencies and phases. A prime example is provided by the unicellular biflagellate Chlamydomonas reinhardtii, which typically displays synchronous in-phase beating in a low-Reynolds number version of breaststroke swimming. We report the discovery that ptx1, a flagellar-dominance mutant of C. reinhardtii, can exhibit synchronization in precise antiphase, as in the freestyle swimming stroke. High-speed imaging shows that ptx1 flagella switch stochastically between in-phase and antiphase states, and that the latter has a distinct waveform and significantly higher frequency, both of which are strikingly similar to those found during phase slips that stochastically interrupt in-phase beating of the wild-type. Possible mechanisms underlying these observations are discussed. Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.Support is acknowledged from the Spanish Ministerio de Ciencia y Innovación Grant No. FIS2010-22322-C01 and a Ramón y Cajal Fellowship (I. T.), an EPSRC postdoctoral Fellowship (M. P.), the BBSRC, the EPSRC, ERC Advanced Investigator Grant No. 247333, and a Senior Investigator Award from the Wellcome Trust (R. E. G.)Peer Reviewe

Multi-dimensional data indexing and range query processing via Voronoi diagram for internet of things

In a typical Internet of Things (IoT) deployment such as smart cities and Industry 4.0, the amount of sensory data collected from physical world is significant and wide-ranging. Processing large amount of real-time data from the diverse IoT devices is challenging. For example, in IoT environment, wireless sensor networks (WSN) are typically used for the monitoring and collecting of data in some geographic area. Spatial range queries with location constraints to facilitate data indexing are traditionally employed in such applications, which allows the querying and managing the data based on SQL structure. One particular challenge is to minimize communication cost and storage requirements in multi-dimensional data indexing approaches. In this paper, we present an energy- and time-efficient multidimensional data indexing scheme, which is designed to answer range query. Specifically, we propose data indexing methods which utilize hierarchical indexing structures, using binary space partitioning (BSP), such as kd-tree, quad-tree, k-means clustering, and Voronoi-based methods to provide more efficient routing with less latency. Simulation results demonstrate that the Voronoi Diagram-based algorithm minimizes the average energy consumption and query response time