Dephasing of Kuramoto oscillators in kinetic regime towards a fixed asymptotically free state

We study the kinetic Kuramoto model for coupled oscillators. We prove that for any regular asymptotically free state, if the interaction is small enough, it exists a solution which is asymptotically close to it. For this class of solution the order parameter vanishes to zero, showing a behavior similar to the phenomenon of Landau damping in plasma physics. We obtain an exponential decay of the order parameter in the case on analytical regularity of the asymptotic state, and a polynomial decay in the case of Sobolev regularity

On the complete phase synchronization for the Kuramoto model in the mean-field limit

We study the Kuramoto model for coupled oscillators. For the case of identical natural frequencies, we give a new proof of the complete frequency synchronization for all initial data; extending this result to the continuous version of the model, we manage to prove the complete phase synchronization for any non-atomic measure-valued initial datum. We also discuss the relation between the boundedness of the entropy and the convergence to an incoherent state, for the case of non identical natural frequencies

In Search of the Americanization: Candidates and Political Campaigns in European General Election

The digital platform has deeply changed the electoral campaigns, producing a consequent evolution of political consulting. Social networks have become the mainstream media so that the digital strat..

Exponential dephasing of oscillators in the Kinetic Kuramoto Model

We study the kinetic Kuramoto model for coupled oscillators with coupling constant below the synchronization threshold. We manage to prove that, for any analytic initial datum, if the interaction is small enough, the order parameter of the model vanishes exponentially fast, and the solution is asymptotically described by a free flow. This behavior is similar to the phenomenon of Landau damping in plasma physics. In the proof we use a combination of techniques from Landau damping and from abstract Cauchy-Kowalewskaya theorem

Characterizing the functionality of transmembrane ion channels using planar bilayer membranes device and stopped flow spectrometer

Transmembrane ion channels can be used in biomaterials as a way to selectively allow only certain molecules to pass through a given membrane. To produce these types of membranes predictably and reliably for commercial activity, its characterization is crucial. We have characterized the conductivity and ion selectivity of NaChBac, a voltage-gated sodium channel from Bacillus haloduran, using a planar bilayer membrane device. Furthermore, we have devised a dye-free flux assay to measure the channel function using stopped flow spectrometer.. Planar bilayer membrane is a common technique for ion channels function characterization. We first incorporated purified NaChBac protein into lipid vesicle. The proteoliposome is then fused to a lipid bilayer. By applying a controllable potential across the protein-embedded bilayer and measuring the current, the conductivity and permeability of the protein can be studied. We have tested NaChBac’s relative permeability for different ions using bi-ionic conditions. We found that the single channel conductivity of NaChBac to be 16.2 pS, which is similar to 12 pS, the value acquired from patch clamp experiment on live cell overexpressing NaChBac. We also found that the ion selectivity of NaChBac of K+ and Ca2+ to that of similar Na+, which was not the case in the same patch clamp study. In addition, we have devised a flux assay for ion channels that uses a stopped flow spectrometer. Conventional flux assay for ion channels requires the use of ion-specific dyes. However the availability of the dyes and their selectivity limits the scope of ion channels that can be tested in a fluorescence flux assay. In our method, NaChBac-incorporating liposomes were diluted into a hypotonic solution, and the proteoliposome swells as a result of sodium ion influx through the protein. Mie scattering is measured and used to determine the size change of proteoliposome that is caused by solute flux. With this method, we have been able to characterize the ion conducting function of purified NaChBac protein

I mostri prima della scienza dei mostri. Nascite mostruose, superstizioni e procedure nei secoli che precedono la moderna teratologia.

The purpose of this study is to analyze some peculiar aspects on the conception of monsters and monstrous births in the centuries preceding the emergence of modern teratology. A “new” discipline, a branch of biology and, in particular, comparative embryology, whose scientific basis was laid by the studies of Etienne and Isidore Geoffroy Saint-Hilaire, in the first half of the nineteenth century. At the beginning I will show a brief summary of the multiple and heterogeneous theories which, in very different times, have tried to explain the causes of the nature and genesis of monsters. We will then go inside the very delicate question on the position of the soul, in man and monsters in particular, which had a direct influence on the possibility of saving from eternal oblivion, in the short time they usually survived, those small deformed creatures.The purpose of this study is to analyze some peculiar aspects on the conception of monsters and monstrous births in the centuries preceding the emergence of modern teratology. A “new” discipline, a branch of biology and, in particular, comparative embryology, whose scientific basis was laid by the studies of Etienne and Isidore Geoffroy Saint-Hilaire, in the first half of the nineteenth century. At the beginning I will show a brief summary of the multiple and heterogeneous theories which, in very different times, have tried to explain the causes of the nature and genesis of monsters. We will then go inside the very delicate question on the position of the soul, in man and monsters in particular, which had a direct influence on the possibility of saving from eternal oblivion, in the short time they usually survived, those small deformed creatures

Sparsification Enables Predicting Kissing Hairpin Pseudoknot Structures of Long RNAs in Practice

While computational RNA secondary structure prediction is an important tool in RNA research, it is still fundamentally limited to pseudoknot-free structures (or at best very simple pseudoknots) in practice. Here, we make the prediction of complex pseudoknots - including kissing hairpin structures - practically applicable by reducing the originally high space consumption. For this aim, we apply the technique of sparsification and other space-saving modifications to the recurrences of the pseudoknot prediction algorithm by Chen, Condon and Jabbari (CCJ algorithm). Thus, the theoretical space complexity of free energy minimization is reduced to Theta(n^3+Z), in the sequence length n and the number of non-optimally decomposable fragments ("candidates") Z. The sparsified CCJ algorithm, sparseCCJ, is presented in detail. Moreover, we provide and compare three generations of CCJ implementations, which continuously improve the space requirements: the original CCJ implementation, our first modified implementation, and our final sparsified implementation. The two latest implementations implement the established HotKnots DP09 energy model. In our experiments, using 244GB of RAM, the original CCJ implementation failed to handle sequences longer than 195 bases; sparseCCJ handles our pseudoknot data set (up to about length 400 bases) in this space limit. All three CCJ implementations are available at https://github.com/HosnaJabbari/CCJ

Towards the molecular workshop: entropy-driven designer molecules, entropy activation, and nanomechanical devices

We introduce some basic concepts for designer molecules with functional units which are driven by entropic rather than energetic forces. This idea profits from the mechanically interlocked nature of topological molecules such as catenanes and rotaxanes, which allows for mobile elements whose accessible configuration space gives rise to entropic intramolecular forces. Such entropy-driven designer molecules open the possibility for externally controllable functional molecules and nanomechanical devices.Comment: 4 pages, 4 figure