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Alexander Lorz (KAUST and Université Pierre et Marie Curie)  HS 13, 2nd floor of Fak.Mathematik Uni Wien  Sat, 29. Jul 17, 16:20 
Mathematics meets oncology: from Adaptive evolution to Zebrafish  

James Greene (Rutgers University)  HS 13, 2nd floor of Fak.Mathematik Uni Wien  Sat, 29. Jul 17, 15:40 
The role of induced drug resistance in cancer chemotherapy  

Lisa Gabler (Medical University, Vienna)  HS 13, 2nd floor of Fak.Mathematik Uni Wien  Sat, 29. Jul 17, 15:10 
Coexpression networkbased identification of molecular subtypes in cancer  

John King (University of Nottingham)  HS 13, 2nd floor of Fak.Mathematik Uni Wien  Sat, 29. Jul 17, 14:10 
Mathematical modeling of biological tissue growth  

Dominik Wodarz (University of California, Irvine)  HS 13, 2nd floor of Fak.Mathematik Uni Wien  Sat, 29. Jul 17, 13:30 
Oncolytic virus therapy: Dynamics of virus spread at low infection multiplicities  

Min Tang (Shanghai Jiao Tong University)  HS 13, 2nd floor of Fak.Mathematik Uni Wien  Sat, 29. Jul 17, 11:10 
The role of intracellular pathways on the E.coli population dynamics  

Maria LukácováMedvidová (University of Mainz)  HS 13, 2nd floor of Fak.Mathematik Uni Wien  Sat, 29. Jul 17, 10:30 
Mathematical and numerical modelling of cancer invasion  

DanaAdriana Botesteanu (University of Maryland)  HS 13, 2nd floor of Fak.Mathematik Uni Wien  Sat, 29. Jul 17, 9:40 
Modeling cancer cell growth dynamics in vitro in response to antimitotics  

Christoph Bock (Center for Molecular Medicine, Vienna)  HS 13, 2nd floor of Fak.Mathematik Uni Wien  Sat, 29. Jul 17, 9:00 
Bioinformatics for personalized medicine: Looking beyond the genome  

Bernhard Englinger (Medical University, Vienna)  HS 13, 2nd floor of Fak.Mathematik Uni Wien  Fri, 28. Jul 17, 17:00 
Mathematical models to predict intracellular drug distribution – Do they work?  

Michael Breitenbach (University of Salzburg)  HS 13, 2nd floor of Fak.Mathematik Uni Wien  Fri, 28. Jul 17, 16:10 
The human NADPH oxidase, Nox4, its S. cerevisiae ortholog, Yno1, and its role in regulating the actin cytoskeleton  

Natalia Komarova (University of California, Irvine)  HS 13, 2nd floor of Fak.Mathematik Uni Wien  Fri, 28. Jul 17, 15:30 
Stochastic Calculus of Stem Cells  

Thomas Mohr (Medical University, Vienna)  HS 13, 2nd floor of Fak.Mathematik Uni Wien  Fri, 28. Jul 17, 14:40 
Deciphering gene coexpression networks in tumor endothelium  

Michael Speicher (Medical University, Graz)  HS 13, 2nd floor of Fak.Mathematik Uni Wien  Fri, 28. Jul 17, 14:00 
Inferring expressed genes by wholegenome sequencing of plasma DNA  

Heyrim Cho (University of Maryland)  HS 13, 2nd floor of Fak.Mathematik Uni Wien  Fri, 28. Jul 17, 11:30 
Modeling the chemotherapyinduced selection of drugresistant traits during tumor growth  

Anna MarciniakCzochra (University of Heidelberg)  HS 13, 2nd floor of Fak.Mathematik Uni Wien  Fri, 28. Jul 17, 10:50 
Mathematical Modeling of Clonal Dynamics in Acute Leukemias  

Michael Medvedev (Kansas)  WPI, OMP 1, Seminar Room 08.135  Fri, 28. Jul 17, 10:00 
Quasinonlinear theory of the Weibel instability  
Astrophysical and highenergydensity laboratory plasmas often have largeamplitude, subLarmorscale electromagnetic fluctuations excited by various kineticstreaming or anisotropydriven instabilities. The Weibel (or the filamentation) instability is particularly important because it can rapidly generate strong magnetic fields, even in the absence of seed fields. Particles propagating in collisionless plasmas with such smallscale magnetic fields undergo stochastic deflections similar to Coulomb collisions, with the magnetic pitchangle diffusion coefficient representing the effective "collision" frequency. We show that this effect of the plasma "quasicollisionality" can strongly affect the growth rate and evolution of the Weibel instability in the deeply nonlinear regime. This result is especially important for understanding cosmicraydriven turbulence in an upstream region of a collisionless shock of a gammaray burst or a supernova. We demonstrate that the quasicollisions caused by the fields generated in the upstream suppress the instability slightly but can never shut it down completely. This confirms the assumptions made in the selfsimilar model of the collisionless foreshock.  

Michael Bergmann (Medical University, Vienna)  HS 13, 2nd floor of Fak.Mathematik Uni Wien  Fri, 28. Jul 17, 9:50 
The understanding of the DNA damage response in solid tumors and the development of oncolytic influenza viruses  

Benoit Perthame (Université Pierre et Marie Curie)  HS 13, 2nd floor of Fak.Mathematik Uni Wien  Fri, 28. Jul 17, 9:10 
Modeling of living tissues and free boundary asymptotics  

Denis StOnge (Princeton)  WPI, OMP 1, Seminar Room 08.135  Thu, 27. Jul 17, 16:00 
Plasma dynamo  

Dmitri Uzdensky (UC Boulder)  WPI, OMP 1, Seminar Room 08.135  Thu, 27. Jul 17, 10:30 
Nonthermal particle acceleration in relativistic collisionless magnetic reconnection  
As a fundamental process converting magnetic to plasma energy in highenergy astrophysical plasmas, relativistic magnetic reconnection is a leading explanation for the acceleration of particles to the ultrarelativistic energies necessary to power nonthermal emission (especially Xrays and gammarays) in pulsar magnetospheres and pulsar wind nebulae, coronae and jets of accreting black holes, and gammaray bursts. An important objective of plasma astrophysics is therefore the characterization of nonthermal particle acceleration (NTPA) effected by reconnection. Reconnectionpowered NTPA has been demonstrated over a wide range of physical conditions using large twodimensional (2D) kinetic simulations. However, its robustness in realistic 3D reconnection  in particular, whether the 3D relativistic driftkink instability (RDKI) disrupts NTPA  has not been systematically investigated, although pioneering 3D simulations have observed NTPA in isolated cases. Here we present the first comprehensive study of NTPA in 3D relativistic reconnection in collisionless electronpositron plasmas, characterizing NTPA as the strength of 3D effects is varied systematically via the length in the third dimension and the strength of the guide magnetic field. We find that, while the RDKI prominently perturbs 3D reconnecting current sheets, it does not suppress particle acceleration, even for zero guide field; fully 3D reconnection robustly and efficiently produces nonthermal powerlaw particle spectra closely resembling those obtained in 2D. This finding provides strong support for reconnection as the key mechanism powering highenergy flares in various astrophysical systems. We also show that strong guide fields significantly inhibit NTPA, slowing reconnection and limiting the energy available for plasma energization, yielding steeper and shorter powerlaw spectra.  

Vladimir Zhdankin (UC Boulder)  WPI, OMP 1, Seminar Room 08.135  Thu, 27. Jul 17, 10:00 
Particle acceleration in relativistic kinetic turbulence  
We present results from particleincell simulations of driven turbulence in magnetized, collisionless, and relativistic pair plasmas. We find that the fluctuations are consistent with the classical k −5/3 ¡Ñ magnetic energy spectrum at fluid scales and a steeper k −4 ¡Ñ spectrum at subLarmor scales, where k¡Ñ is the wave vector perpendicular to the mean field. We demonstrate the development of a nonthermal, powerlaw particle energy distribution f(E)¡E−¥á, with an index ¥á that decreases with increasing magnetization and increases with an increasing system size (relative to the characteristic Larmor radius). Our simulations indicate that turbulence can be a viable source of energetic particles in highenergy astrophysical systems, such as pulsar wind nebulae, if scalings asymptotically become insensitive to the system size.  

Jonathan Squire (Caltech)  WPI, OMP 1, Seminar Room 08.135  Wed, 26. Jul 17, 16:00 
Resonant instabilities: dustgas coupling and others?  
It is shown that grains streaming through a fluid are generically unstable if their velocity, projected along some direction, matches the phase velocity of a fluid wave. This can occur whenever grains stream faster than a fluid wave. The wave itself can be quite generalsound waves, magnetosonic waves, epicyclic oscillations, and BruntV\"ais\"al\"a oscillations each generate instabilities, for example. A simple expression for this "resonant drag instability" (RDI) growth rate is derived. This expression (i) illustrates why such instabilities are so virulent and generic, and (ii) allows for simple analytic computation of RDI growth rates and properties for different fluid systems. As examples, we introduce several new instabilities, which could see application across a variety of astrophysical systems from protoplanetary disks to galactic outflows.  

Archie Bott (Oxford)  WPI, OMP 1, Seminar Room 08.135  Wed, 26. Jul 17, 10:00 
When are plasmas collisional?  

Nuno Loureiro (MIT)  WPI, OMP 1, Seminar Room 08.135  Tue, 25. Jul 17, 16:00 
Fullykinetic versus reducedkinetic modelling of collisionless plasma turbulence Pulsedpower driven magnetic reconnection experiments  
We report the results of a direct comparison between different kinetic models of collisionless plasma turbulence in two spatial dimensions. The models considered include a first principles fullykinetic (FK) description, two widely used reduced models [gyrokinetic (GK) and hybridkinetic (HK) with fluid electrons], and a novel reduced gyrokinetic approach (KREHM). Two different ion beta (â i ) regimes are considered: 0.1 and 0.5. For â i =0.5 , good agreement between the GK and FK models is found at scales ranging from the ion to the electron gyroradius, thus providing firm evidence for a kinetic Alfv'en cascade scenario. In the same range, the HK model produces shallower spectral slopes, presumably due to the lack of electron Landau damping. For â i =0.1 , a detailed analysis of spectral ratios reveals a slight disagreement between the GK and FK descriptions at kinetic scales, even though kinetic Alfv'en fluctuations likely still play a significant role. The discrepancy can be traced back to scales above the ion gyroradius, where the FK and HK results seem to suggest the presence of fast magnetosonic and ion Bernstein modes in both plasma beta regimes, but with a more notable deviation from GK in the lowbeta case. The identified practical limits and strengths of reducedkinetic approximations, compared here against the fullykinetic model on a casebycase basis, may provide valuable insight into the main kinetic effects at play in turbulent collisionless plasmas, such as the solar wind.  

Francois Rincon (Toulouse)  WPI, OMP 1, Seminar Room 08.135  Tue, 25. Jul 17, 10:00 
Some thoughts on theoretical problems and appoaches in dynamo theory  

Nuno Loureiro (MIT)  WPI, OMP 1, Seminar Room 08.135  Mon, 24. Jul 17, 16:45 
MHD turbulence + magnetic reconnection  
The current understanding of magnetohydrodynamic (MHD) turbulence envisions turbulent eddies which are anisotropic in all three directions. In the plane perpendicular to the local mean magnetic field, this implies that such eddies become currentsheetlike structures at small scales. We analyze the role of magnetic reconnection in these structures and conclude that reconnection becomes important at a scale ¥ë¡LS −4/7L, where SL is the outerscale (L) Lundquist number and ¥ë is the smallest of the fieldperpendicular eddy dimensions. This scale is larger than the scale set by the resistive diffusion of eddies, therefore implying a fundamentally different route to energy dissipation than that predicted by the Kolmogorovlike phenomenology. In particular, our analysis predicts the existence of the subinertial, reconnection interval of MHD turbulence, with the estimated scaling of the Fourier energy spectrum E(k¡Ñ)¡ðk−5/2¡Ñ, where k¡Ñ is the wave number perpendicular to the local mean magnetic field. The same calculation is also performed for high (perpendicular) magnetic Prandtl number plasmas (Pm), where the reconnection scale is found to be ¥ë/L¡S−4/7LPm−2/7.  

Alex Schekochihin (Oxford)  WPI, OMP 1, Seminar Room 08.135  Mon, 24. Jul 17, 16:00 
MHD turbulence in 2017: end of the road? ++kinetic extensions  

Yohei Kawazura (Oxford)  WPI, OMP 1, Seminar Room 08.135  Mon, 24. Jul 17, 10:30 
Hybrid GKisothermal electrons code + ion heating calculations  

Lev Arzamasskiy (Princeton)  WPI, OMP 1, Seminar Room 08.135  Mon, 24. Jul 17, 10:00 
Hybridkinetic simulations of solar wind turbulence  

David Hatch (UT Austin)  WPI, OMP 1, Seminar Room 08.135  Thu, 20. Jul 17, 16:00 
Flow Shear Suppression of Pedestal TurbulenceA First Principles Theoretical Framework  
A combined analytic and computational gyrokinetic approach is developed to address the question of the scaling of pedestal turbulent transport with arbitrary levels of E×B shear. Due to strong gradients and shaping in the pedestal, the instabilities of interest are not curvaturedriven like the core instabilities. By extensive numerical (gyrokinetic) simulations, it is demonstrated that pedestal modes respond to shear suppression very much like the predictions of a basic analytic decorrelation theory. The quantitative agreement between the two provides us with a new dependable, first principles (physics based) theoretical framework to predict the efficacy of shear suppression in burning plasmas that lie in a lowshear regime not accessed by present experiments.  

Denis StOnge (Princeton)  WPI, OMP 1, Seminar Room 08.135  Wed, 19. Jul 17, 16:30 
The Dimits Shift in a OneField Fluid Model  
The twodimensional TerryHorton equation is shown to exhibit the Dimits shift when suitably modified to capture both the nonlinear enhancement of zonal/driftwave interactions and the existence of residual RosenbluthHinton states. This phenomena persists through numerous simplifications of the equation, including a quasilinear approximation as well as a fourmode truncation. Analytic progress on the truncated system is reported, focused on determining the growth rates of zonal flows and calculating the upper bound of the Dimits shift. The results for the truncated system are then used to estimate the Dimits shift of the fully nonlinear system. A new understanding is thus developed on the fundamental nature of the Dimits shift, both on its operation and its eventual termination.  

Justin Ball (EPFLausanne)  WPI, OMP 1, Seminar Room 08.135  Wed, 19. Jul 17, 10:00 
Optimized updown asymmetry to drive fast intrinsic rotation in tokamaks  
Breaking the updown symmetry of the tokamak poloidal crosssection can significantly increase the spontaneous rotation due to turbulent momentum transport. In this work, we optimize the shape of flux surfaces with both tilted elongation and tilted triangularity in order to maximize this drive of intrinsic rotation. Nonlinear gyrokinetic simulations demonstrate that adding optimallytilted triangularity can double the momentum transport of a tilted elliptical shape. This work indicates that tilting the elongation and triangularity in an ITERlike device can reduce the energy transport and drive intrinsic rotation with an Alfv\'{e}n Mach number on the order of 1% . This rotation is four times larger than the rotation expected in ITER and is sufficient to stabilize MHD instabilities. It is shown that this optimal shape can be created using the shaping coils of several experiments.  

Alessandro Geraldini (Oxford)  WPI, OMP 1, Seminar Room 08.135  Tue, 18. Jul 17, 16:00 
Gyrokinetic treatment of a grazing angle magnetic presheath  
We develop a gyrokinetic treatment for ions in the magnetic presheath, close to the plasmawall boundary. We focus on magnetic presheaths with a small magnetic field to wall angle, $\alpha \ll 1$ (in radians). Characteristic lengths perpendicular to the wall in such a magnetic presheath scale with the typical ion Larmor orbit size, ${\rho }_{{\rm{i}}}$. The smallest scale length associated with variations parallel to the wall is taken to be across the magnetic field, and ordered $l={\rho }_{{\rm{i}}}/\delta $, where $\delta \ll 1$ is assumed. The scale lengths along the magnetic field line are assumed so long that variations associated with this direction are neglected. These orderings are consistent with what we expect close to the divertor target of a tokamak. We allow for a strong component of the electric field ${\bf{E}}$ in the direction normal to the electron repelling wall, with strong variation in the same direction. The large change of the electric field over an ion Larmor radius distorts the orbit so that it is not circular. We solve for the lowest order orbits by identifying coordinates, which consist of constants of integration, an adiabatic invariant and a gyrophase, associated with periodic ion motion in the system with $\alpha =\delta =0$. By using these new coordinates as variables in the limit $\alpha \sim \delta \ll 1$, we obtain a generalised ion gyrokinetic equation. We find another quantity that is conserved to first order and use this to simplify the gyrokinetic equation, solving it in the case of a collisionless magnetic presheath. Assuming a Boltzmann response for the electrons, a form of the quasineutrality equation that exploits the change of variables is derived. The gyrokinetic and quasineutrality equations give the ion distribution function and electrostatic potential in the magnetic presheath if the entrance boundary condition is specified.  

Silvia Espinosa (MIT)  WPI, OMP 1, Seminar Room 08.135  Tue, 18. Jul 17, 10:00 
Pedestal radial flux measuring method to prevent impurity accumulation  
The use of highz wall materials attempts to shift the fusion challenge from heat handling to impurity removal. We demonstrate that not only the impurity density inout asymmetry but also the poloidal flow has a major impact on the radial impurity flux direction. This realization provides the first method of measuring the flux from available diagnostics, without the need of a computationally demanding kinetic calculation of the full bulk ion response. Moreover, it affords insight into optimal tokamak operation to avoid impurity accumulation while allowing free fueling.  

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