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January 01, 2013
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Date:06ThursdayFebruary 2020Colloquia
Testing Gravity with Cold Atoms
More information Time 11:15 - 12:30Location Edna and K.B. Weissman Building of Physical SciencesLecturer Guglielmo M. Tino
University of FlorenceOrganizer Faculty of PhysicsContact Abstract Show full text abstract about The ability to control the quantum degrees of freedom of ato...» The ability to control the quantum degrees of freedom of atoms using laser light opened the way to precision measurements of fundamental physical quantities. I will describe experiments for precision tests of gravitational physics using new quantum devices based on ultracold atoms, namely, atom interferometers and optical clocks. I will report on the measurement of the gravitational constant G with a Rb Raman interferometer, on experiments based on Bloch oscillations of Sr atoms confined in an optical lattice for gravity measurements at small spatial scales, and on new tests of the Einstein equivalence principle. I will also discuss prospects to use atoms as new detectors for gravitational waves and for experiments in space. -
Date:06ThursdayFebruary 2020Lecture
The earliest evidence of a Lisfranc’s fracture
More information Time 11:30 - 12:30Location Nella and Leon Benoziyo Building for Biological SciencesLecturer Sara Borgel
Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University. The Dan David Center for Human Evolution and Bio-history Research, The Shmunis Family Anthropology InstituteOrganizer Academic Educational ResearchContact Abstract Show full text abstract about Recent archaeological excavations at Manot Cave, an Early Up...» Recent archaeological excavations at Manot Cave, an Early Upper Palaeolithic site in the Western Galilee, Israel, retrieved the remains of a partial left foot of a young adult, including the talus, the calcaneus, the cuboid and the first, second and fifth metatarsals. The pedal remains were found close to one another, in the same archaeological unit, and were associated with an Early Upper Palaeolithic assemblage.
Our study aimed at describing the anatomy of the Manot Cave pedal bones using morphometric parameters. A comparison to foot bones of recent modern humans, Anatomically Modern Humans and Neanderthals was carried out to establish the Manot Cave specimen population affiliation. Additionally, µCT images were used to verify a suspected injury in the base of the second metatarsal.
The shape and size of the Manot pedal bones indicated a modern morphology for all bones, albeit few Neanderthal-like characteristics. Imaging analysis confirmed the existence of a healed trauma in the second metatarsal, with the plantar third of the base misaligned with the shaft and a fracture line on the lateral side. These features are consistent with a fracture known as Lisfranc’s fracture, most probably caused by an impact to the dorsum of the foot. This injury usually leads to ligamentous instability and collapse of the transverse and longitudinal arches, causing severe walking difficulties. Full recovery requires rest and immobility for several weeks.
As mobility was crucial to maintain the hunter-gatherer lifeway of this group, the survival of this individual indicates a supportive community at Manot Cave. -
Date:06ThursdayFebruary 2020Lecture
Double Special Guest Seminar: Prof. Lynn Hedrick and Prof. Klaus Ley.
More information Time 14:00 - 15:00Location Wolfson Building for Biological ResearchLecturer Prof. Lynn Hedrick and Prof. Klaus Ley
La Jolla Institute for ImmunologyOrganizer Department of Systems ImmunologyContact -
Date:09SundayFebruary 2020Lecture
Utilization of machine learning techniques to retrieve aerosol and cloud properties from remote sensing measurements
More information Time 11:00 - 11:00Location Sussman Family Building for Environmental SciencesLecturer Michal Segal Rosenheimer
Tel Aviv UniversityOrganizer Department of Earth and Planetary SciencesContact -
Date:09SundayFebruary 2020Lecture
From contraction waves to rupture resistance – biological tissues as active solids
More information Time 11:00 - 12:00Location Perlman Chemical Sciences BuildingLecturer Dr. Shahaf Armon
Dept. Physics of Complex Systems, WISOrganizer Department of Molecular Chemistry and Materials ScienceContact Abstract Show full text abstract about Following our recent observations of contraction waves in th...» Following our recent observations of contraction waves in the primitive epithelium of Placozoa, we develop a model of tissues as sheets of contractile cells. The simple model assumes only a strain-threshold for contraction, and explains/predicts a variety of unique and surprising phenomena, e.g.: contraction waves in response to external stress, spontaneously-compressed steady-state, emerged limit-cycles, mechanical frustration and active resistance to rupture. In the talk I will present both the experimental observations and the model results. This model of “active cohesion” may be relevant to any epithelial tissue, to manufacturing of synthetic active materials, and to models of evolution of multicellularity. -
Date:09SundayFebruary 2020Lecture
Energy Saving/Producing Wastewater Treatment Processes in the Context of Circular Economy
More information Time 13:00 - 14:00Title SAERI- Sustainability and Energy Research InitiativeLocation Nella and Leon Benoziyo Building for Biological SciencesLecturer Prof. Isam Sabbah
Head of the Prof. Ephraim Katzir Department of Biotechnology Engineering, Braude College & Senior researcher at the Institute of Applied Research, the Galilee SocietyOrganizer Weizmann School of ScienceContact -
Date:09SundayFebruary 2020Lecture
Packets of Diffusing Particles Exhibit Universal Exponential Tails
More information Time 13:15 - 13:15Location Edna and K.B. Weissman Building of Physical SciencesLecturer Stas Burov, Bar-Ilan University Organizer Clore Center for Biological PhysicsContact Abstract Show full text abstract about Brownian motion is a Gaussian process described by the centr...» Brownian motion is a Gaussian process described by the central limit theorem. However, exponential decays of the positional probability density function $P(X,t)$ of packets of spreading random walkers, were observed in numerous situations that include glasses, live cells and bacteria suspensions. We show that such exponential behavior is generally valid in a large class of problems of transport in random media. By extending the Large Deviations approach for a continuous time random walk we uncover a general universal behavior for the decay of the density. It is found that fluctuations in the number of steps of the random walker, performed at finite time, lead to exponential decay (with logarithmic corrections) of P(X,t). This universal behavior holds also for short times, a fact that makes experimental observations readily achievable. -
Date:09SundayFebruary 2020Lecture
Packets of Diffusing Particles Exhibit Universal Exponential Tails
More information Time 13:15 - 13:15Location Edna and K.B. Weissman Building of Physical SciencesLecturer Stas Burov
Bar-Ilan UniversityOrganizer Department of Physics of Complex SystemsContact Abstract Show full text abstract about Brownian motion is a Gaussian process described by the centr...» Brownian motion is a Gaussian process described by the central limit theorem. However, exponential decays of the positional probability density function $P(X,t)$ of packets of spreading random walkers, were observed in numerous situations that include glasses, live cells and bacteria suspensions. We show that such exponential behavior is generally valid in a large class of problems of transport in random media. By extending the Large Deviations approach for a continuous time random walk we uncover a general universal behavior for the decay of the density. It is found that fluctuations in the number of steps of the random walker, performed at finite time, lead to exponential decay (with logarithmic corrections) of $P(X,t)$. This universal behavior holds also for short times, a fact that makes experimental observations readily achievable. -
Date:09SundayFebruary 2020Lecture
The Genomics of Fasting and Inflammation Reveals Dynamic Cooperativity Between Transcription Factors
More information Time 15:00 - 16:00Location Arthur and Rochelle Belfer Building for Biomedical ResearchLecturer Dr. Ido Goldstein
Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agriculture, Food and Environment. HUJI, IsraelContact -
Date:10MondayFebruary 202011TuesdayFebruary 2020Conference
Israel Plant Ecology meeting
More information Time 08:00 - 08:00Chairperson Tamir KleinHomepage -
Date:10MondayFebruary 202011TuesdayFebruary 2020Conference
The Weizmann-Caltech Symposium on The Carbon Cycle
More information Time 08:00 - 08:00Location The David Lopatie Conference CentreChairperson Itay Halevy -
Date:10MondayFebruary 2020Colloquia
The chiral induced spin selectivity- How it is relevant in Chemistry, Physics, and Biology
More information Time 11:00 - 12:15Location Gerhard M.J. Schmidt Lecture HallLecturer Prof. Ron Naaman
Department of Chemical and Biological Physics, WISOrganizer Faculty of ChemistryContact -
Date:10MondayFebruary 2020Lecture
Non-enzymatic modifications on histones drive chamges in chromatin structure and function
More information Time 14:00 - 15:00Location Max and Lillian Candiotty BuildingLecturer Dr. Yael David Organizer Department of Immunology and Regenerative BiologyContact -
Date:10MondayFebruary 2020Lecture
Thermal conductance of one dimensional disordered harmonic chains
More information Time 14:15 - 14:15Location Edna and K.B. Weissman Building of Physical SciencesLecturer Biswarup Ash - WIS Organizer Department of Physics of Complex SystemsContact Abstract Show full text abstract about Heat transfer in solids is usually described in terms of Fou...» Heat transfer in solids is usually described in terms of Fourier's law according to which
the thermal conductance of a material scales inversely with its length or, equivalently, thermal
conductivity is independent of sample length. Theoretical and experimental studies over the
past decade have demonstrated that Fourier's law is violated for a variety of one-dimensional
systems. Despite the large number of studies of many intriguing models, the validity criteria
for Fourier's law remain elusive, and a breakdown of Fouriers law seems to be commonplace.
In this talk, I will discus heat conduction mediated by longitudinal phonons in one dimensional disordered harmonic chains to understand the role of different parameters that may affect
the scaling of thermal conductance in these systems. Using scaling properties of the phonon
density of states and localization in disordered systems, we find non-trivial scaling of the thermal conductance with the system size. Our theoretical findings are corroborated by extensive
numerical analysis. We show that, suprisingly, the thermal conductance of a system with strong
disorder, characterized by a `heavy-tailed' probability distribution, and with large impedance
mismatch between the bath and the system scales normally with the system size, i.e., in a
manner consistent with Fourier's law. We identify a dimensionless scaling parameter, related
to the temperature scale and the localization length of the phonons, through which the thermal conductance for different models of disorder and different temperatures follows a universal
behavior.
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Date:11TuesdayFebruary 2020Lecture
To be announced
More information Time 10:00 - 10:15Location Nella and Leon Benoziyo Building for Biological SciencesLecturer Yarden Tzur
Dept. of Biomolecular Sciences-WISOrganizer Department of Biomolecular SciencesContact -
Date:11TuesdayFebruary 2020Lecture
Planar and Twisted π-Conjugated Materials
More information Time 11:00 - 12:00Location Helen and Milton A. Kimmelman BuildingLecturer Dr. Ori Gidron
Institute of Chemistry, The Hebrew University of JerusalemOrganizer Department of Molecular Chemistry and Materials ScienceContact Abstract Show full text abstract about Planarity plays a crucial role in determining the electronic...» Planarity plays a crucial role in determining the electronic and optical properties of π-conjugated backbones. Here I will discuss two examples of non-planar and planar systems: twisted acenes and planar furan-based macrocycles.
In the first part, I will demonstrate how twisting affects the electronic, optical and chiroptical properties of acenes. We have introduced a series of twisted acenes, having an anthracene backbone diagonally tethered by an n-alkyl bridge, which induces different degrees of twisting. This helically-locked system allows us to systematically monitor the effect of twisting on electronic and optical properties of anthracene. The effect of twisting on chiroptical properties, charge delocalization and π-conjugation will also be demonstrated.
In the second part, I will present bifuranimide as a stable furan containing analog, which resulted in the introduction of the first macrocyclic furans. These π-conjugated macrocycles were found to be completely planar, in contrast with thiophene macrocycles which are highly-twisted. The prospects of macrocyclic furans as π-conjugated analogs of crown-ethers and synthons for cycloarenes by multiple Diels–Alder cycloadditions will be discussed.
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Date:11TuesdayFebruary 2020Lecture
A common neuronal mechanism underlying free and creative behavior in the human brain
More information Time 12:30 - 12:30Location Gerhard M.J. Schmidt Lecture HallLecturer Prof. Rafael Malach
Dept of Neurobiology, WISOrganizer Department of Brain SciencesContact Abstract Show full text abstract about Free behavior is likely the most fundamental and essential a...» Free behavior is likely the most fundamental and essential aspect of human life. It underlies our unique ability to self-generate actions and come up with creative and original solutions. Yet, the brain mechanism that drives such free and creative behaviors remains unknown. In my talk I will present experimental findings supporting the hypothesis that ultra-slow spontaneous (resting state) activity fluctuations are a central and ubiquitous mechanism underlying all types of free behavior. Traces of slow resting state fluctuations can account for the intriguing observation that free behaviors of all types- from generating names to free recall of visual images- are invariably preceded by a wave of slow (1-4 seconds) activity buildup. This buildup can be observed in BOLD-fMRI, intracranial recording of single neurons and more recently, in the massive hippocampal bursts called Sharp Wave Ripples. Could the similar slow dynamics of the spontaneous fluctuations and the anticipatory buildup preceding free behaviors be a mere coincidence? Crucially, I will present evidence that individual differences in the waveforms of spontaneous fluctuations measured during are significantly correlated to the shape of the buildup wave anticipating free and creative events. The critical role of spontaneous activity fluctuations in generating creative decisions is reminiscent of the use of stochastic noise in optimizing solutions in network models.
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Date:12WednesdayFebruary 2020Lecture
Developmental Club Series 2019-20
More information Time 10:00 - 10:00Title Visualizing neural activity: from intracellular signaling to whole-brain network From whole-brain landscape to millisecond dynamicsLocation Arthur and Rochelle Belfer Building for Biomedical ResearchLecturer Dr. Takashi Kawashima Organizer Department of Molecular GeneticsContact -
Date:12WednesdayFebruary 2020Lecture
Exciton and trions in Van der Waals materials and their dynamics under different non-uniform strain configurations
More information Time 11:00 - 12:00Location Gerhard M.J. Schmidt Lecture HallLecturer Dr. Moshe Harats
Faculty of Physics, Freie University BerlinOrganizer Department of Molecular Chemistry and Materials ScienceContact Abstract Show full text abstract about Abstract: In recent years, Van der Waals (2D) materials, ha...» Abstract:
In recent years, Van der Waals (2D) materials, have attracted increasing attention due to their distinctive physical properties. As layered materials, they have been considered for flexible electronics as they can sustain strain higher than 10% without breaking down, although they are only 1-3 atom thick. Their superior mechanical properties led to a renewed interest in the mechanics of thin membranes linked to condensed matter physics. In this talk we will show how we can apply non-uniform strain to a suspended Van der Waals material (WS2) and alter the dynamics of excitons and trions. Surprisingly, we find that as we increase the non-uniformity of the strain, we are able to convert the excitons into trions with almost 100% efficiency without any electrostatic gating. Our results explain inconsistencies in previous experiments and pave the way towards new types of optoelectronic devices.
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Date:12WednesdayFebruary 2020Lecture
Optics, Vision, and Evolution, after Mitchell Feigenbaum 1944-2019
More information Time 11:00 - 11:00Location Edna and K.B. Weissman Building of Physical SciencesLecturer Jean-Pierre Eckmann
University of Geneva, MathematicsOrganizer Clore Center for Biological PhysicsContact Abstract Show full text abstract about Many people are aware of Feigenbaum's astonishing disco...» Many people are aware of Feigenbaum's astonishing discovery of the universality of period doubling, and the constant delta=4.66920 which carries his name.
In the last 13 years of his life Feigenbaum worked on other subjects, and he wrote the manuscript (in TeX) of a book whose title is "Reflections on a Tube".
This is closely related to his life-long interest in optics and aspects of vision. It deals with the optics of images reflected in a cylindrical mirror (usually called anamorphic pictures). He shows that the eye does not interpret ray-tracing, but caustics. But there are two caustics, and therefore, the viewer can actually see two different images. The visual system will often prefer one over the other. The question is the "which" and "why"? Starting from this discovery, Feigenbaum derived other aspects of this observation, dealing with the vision of fish, the "broken" pencil in water, or aspects of the floor of swimming pools. All these examples show two possible images. His study tells me how a simple study in classical optics can lead to interesting questions in perception and the visual system.
I will give an overview of this project. As I discussed with him, over those 13 years, many aspects of his work, I have edited his manuscript so it can be published as a book which should appear in a forseeable future.
