deletions | additions       diff --git a/Introduction.tex b/Introduction.tex  index 3a0c0a0..ebfe310 100644  --- a/Introduction.tex  +++ b/Introduction.tex 
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In order to further probe the system, we performed a number of perturbations affecting both the circadian clock and the cell cycle. In all conditions the two oscillators remained synchronized, and the data were consistent with a scenario in which the coupling is predominantly from the cell cycle to the circadian clock. Moreover, we fitted a parametric form of the coupling functions to the data via maximum likelihood. This clearly identified an acceleration of circadian phase after the division, but the stochastic nature of the problem, the large number of parameters and the particular parametric form of the coupling functions made identifying further interaction points challenging.   Thus, contrary to our expectations, we found that the cell cycle progression exerts a predominant influence on the circadian clock. While fruitful, this analysis in term of peak and division times, implicitly assumes that the phase goes linearly between two events, and thus neglect fast components of the phase dynamic \cite{Kralemann_2008}.   \textbf{Open questions ?}  In a recent study Feillet et al. \cite{Feillet2014} performed similar experiments, with the notable advantage of using the Fucci system to probe the state of the cell cycle. They found that the two oscillators are synchronized, with distribution of circadian phase at division consistent with our own findings, and also noted the effect of divisions on circadian intervals.  Under dexamethasone treatment they found that a fraction of the cells were adopting a different mode of locking, in which a cell divides three times each two circadian cycles. Furthermore they noted that in this condition cell division were clustered in time, a sign of the influence of the circadian clock on the cell cycle. This contrast with our own dexamethasone experiment, in which we found that the timing of divisions was not showing a clear structure.  \textbf{Open questions ?}  %\textit{Our new findings}  In this follow-up study we further analyze the dynamics of the two interacting oscillators by applying probabilistic inference to the whole signal allowing us to reconstruct the full phase dynamic of this interaction. Rather than relying on detected division times we use the measured area of the nucleus as a continuous variable to monitor cell cycle progression, as the nuclear area shows a consistent temporal pattern between two divisions \cite{Fidorra1981}. This analysis indicates that the biological system presents several important features of resonating oscillators and, moreover, allows us to make more specific predictions on distinct cell cycle events affecting the circadian clock, such the condensation of chromosomes starting from prophase during mitosis. We then test those predictions using further markers of cell cycle events. 
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