|Monday 6 December 2021|
|Events for day: Wednesday 20 October 2021|
| 13:30 - 15:00 Weekly Seminar (Online)|
Stochastic Effects of a Transition in the Inflationary Potential
After a brief review of the machinery of stochastic inflation, I introduce a model with a sharp transition in the potential and derive the statistics of the stochastic noise. Then I show how to calculate the probability distribution of curvature perturbations from the corresponding adjoint Fokker-Plack equation. Finally, I make some comments on the tail of the distribution and the relation with primordial black holes. ...
14:00 - 15:00 Wednesday Weekly Seminar - google meet
Measurement of the longitudinal HOMs of the aluminum Cavity for the Iranian Light Source Facility
PARTICLES AND ACCELERATORS
Abstract: The quality of synchrotron radiation is essential to the users, and its improvement is considered an arena of competition between light sources. RF cavity is one of the components of a synchrotron machine that can affect its quality significantly. When excited by the electron beam, higher-order modes of the RF cavity can cause instabilities in the electron beam itself. Hence, identifying such modes' properties and their impact on the beam quality is critical when developing a synchrotron light source. This talk describes the coaxial wire method as an accurate measurement technique for the longitudinal HOMs of our laboratory prototyp ...
14:00 - 15:00 Weekly Seminar
Mechanical characteristics of the nuclear membrane of stem cells, what experiments suggest and what models predict
Embryonic stem (ES) cells have the capacity to differentiate into all cell lineages in vivo, and because of this, the nucleus and the chromatin are kept poised in a particular dynamical state enabling such transitions. Research has shown that the nuclei of stem cells are very soft due to a low level of structural proteins such as lamin A/C and transcriptionally highly active state. In this study, we use the live data of ES cell nuclei in culture obtained by confocal microscopy with a temporal resolution of 10 s and study the shape fluctuations of the nuclei on a time scale of tens of minutes. We quantitatively describe the shape fluctuations ...