April 29, 2015
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Date:26SundayApril 201529WednesdayApril 2015Conference
Cortical Development in Health and Disease
More information Time 08:00 - 18:00Location David Lopatie Conference Centre
Kimmel AuditoriumChairperson Orly ReinerHomepage Contact -
Date:29WednesdayApril 2015Lecture
Cell competition and Tumorigenesis
More information Time 10:00Location Arthur and Rochelle Belfer Building for Biomedical Research
Botnar AuditoriumLecturer Dr. Gines Morata
Centro de Biología Molecular, CSIC-UAM, Universidad Autónoma de Madrid, SpainOrganizer Life SciencesContact -
Date:29WednesdayApril 2015Lecture
Turbulent Magnetic Field Amplification in Young Galaxies
More information Time 10:15 - 11:15Location Dannie N. Heineman Laboratory
Benoziyo Center for Astrophysics Seminar RoomLecturer Jennifer SchoberOrganizer Nella and Leon Benoziyo Center for AstrophysicsContact Abstract Show full text abstract about Magnetic fields play an important role in present-day galaxi...» Magnetic fields play an important role in present-day galaxies, for instance by influencing the star formation process. In models of young galaxies magnetic fields are usually not considered as they were assumed not to be dynamical important at high redshifts. In the presence of turbulence, however, the small-scale or turbulent dynamo can amplify weak magnetic seed fields by randomly stretching, twisting, and folding the field lines. The details of this process depend on the nature of turbulence, i.e. on the hydrodynamic and magnetic Reynolds numbers, and on the compressibility of the gas. In my talk I will introduce the basics of the turbulent dynamo and sketch our recent progress in describing it analytically and numerically. With a model of a typical young galaxy, where turbulence is driven by accretion and by supernova explosions, we determine the growth rate of the small-scale dynamo. We follow the exponential growth of the magnetic field on the viscous scale and also the subsequent transport of the magnetic energy to larger scales in the non-linear dynamo phase. Depending on the parameters of our model we find that equipartition of magnetic and kinetic energy, which corresponds to a field strength of roughly 10^(-5) G, is reached within 4 to 270 Myr. Thus, we expect that the turbulent dynamo can generate strong unordered fields already in very young galaxies which should be considered in future models of galaxy evolution. -
Date:29WednesdayApril 2015Colloquia
Special Chemistry Colloquium - "Bond, Chemical Bond"
More information Time 11:00 - 12:30Location Gerhard M.J. Schmidt Lecture HallLecturer Prof. Wilson Ho
Department of Physics and Astronomy, University of California/USAOrganizer Faculty of ChemistryContact -
Date:29WednesdayApril 2015Lecture
Deviation from identity of macroscopic properties of enantiomers –via water chiral preference. (Is water chiral?)
More information Time 14:00Location Perlman Chemical Sciences Building
Room 404Lecturer Dr. Yosef Scolnik
IYAR (Israel Institute for Advanced Research). Weizmann InstituteOrganizer Department of Molecular Chemistry and Materials ScienceContact Details Show full text description of Abstract Mirror-image asymmetric molecules, i.e. enantiomer...» Abstract
Mirror-image asymmetric molecules, i.e. enantiomers, are classically considered as chemically identical. Parity violation by the nuclear weak force induces a tiny energy difference between chiral isomers. Upon combination with a massive amplification process, expansion of this difference to a detectable macroscopic level may be achieved. In our studies we have prove this in several systems: Stearoylserine "quasi peptide" formation
Solubility and cluster formation of Alanine
Peptide Transitions to alpha –helix, shortly described hereafter and others
We compared structural and dynamic features of synthetic D- and L-polyglutamic acid and polylysine molecules each of 24 identical residues. The helix and random coil configurations and their transition were determined in this study by circular dichroism (CD) and isothermal titration calorimetry (ITC) in water and deuterium oxide. Distinct differences in structure and transition energies between the enantiomer polypeptides were detected by both CD and ITC when dissolved in water. Intriguingly, these differences were by and large abolished in deuterium oxide. Our findings suggest that deviation from physical invariance between the D- and L-polyamino acids is induced in part by different hydration in water which is eliminated in deuterium oxide. We suggest that ortho-H2O, which constitutes 75% of bulk H2O, has a preferential affinity to L-enantiomers.In other words, these studies, prove that indeed water has chiral preferences, Accordingly, Heavy Water has no chiral preference. Differential hydration of enantiomers may have played a role in the selection of L-amino acids by early forms of life.
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Date:29WednesdayApril 2015Lecture
Investigations of Implosions on the National Ignition Facility and discussion on the fusion yield from NIF
More information Time 15:15Location Edna and K.B. Weissman Building of Physical Sciences
Drory AuditoriumLecturer H. A. Scott, B. A. Hammel
Lawrence Livermore National Laboratory, Livermore, CA USAOrganizer Department of Particle Physics and Astrophysics
Plasma SeminarContact Details Show full text description of 15:00 – Light refreshments ...» 15:00 – Light refreshmentsAbstract Show full text abstract about Hydrodynamic instabilities are a primary impediment to the s...» Hydrodynamic instabilities are a primary impediment to the success of inertial confinement fusion (ICF), as they can severely degrade capsule performance [1]. Even with perfectly smooth capsules, the fill tube and capsule support provide perturbations that seed instabilities. Consequently,
understanding the evolution of perturbations and their effects on capsule performance is critical to the success of an ICF program. We discuss here the use of spectroscopic methods to diagnose the growth of hydrodynamic instabilities in imploding capsules. To understand capsule evolution and guide experimental design and interpretation, we use high-resolution HYDRA [2] simulations, postprocessed with Cretin [3], to simulate the spectra produced by capsules with specified initial perturbations. The
spectral simulations cover a wide range of conditions, from the multi-keV hot spot to the cold dense pusher.
For capsules with mid-Z dopants, the resulting X-ray spectrum can be analyzed to obtain information about the plasma conditions. An analysis of the dopant K-shell line emission has been used to estimate the mass of ablator material mixed into the hot spot [4]. Other spectral features can be used to provide information about the shell and further constrain the mixed mass. Other recent work has focused on using spectroscopy to quantitatively characterize the growth of perturbations. Capsules containing a small amount of argon in the gas produce sufficient emission before peak compression to provide radiographic information. The analysis of simulated spectra from capsules with machined perturbations demonstrates the possibility of extracting quantitative measures of perturbation growth.
References
[1] B.A. Hammel, et al, High Energy Density Physics, 6 (2010) 171.
[2] M. Marinak, et al, Phys. Plasmas 8 (2001) 2275.
[3] H.A. Scott, J Quant Spectrosc Radiat Transfer 71 (2001) 681.
[4] S.P. Regan et al. Phys. Rev, Lett. 111, 045001 (2013).