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November 02, 2015

  • Date:22SundayDecember 2024

    Multi-level ecosystem response to drying climate trends

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    Time
    11:00 - 12:00
    Location
    Sussman Family Building for Environmental Sciences
    M. Magaritz seminar room
    LecturerEhud Meron
    AbstractShow full text abstract about Climate change and the development of drier climates threate...»
    Climate change and the development of drier climates threatenecosystems’ health and the services they provide to humans.Understanding ecosystem response to drier climates may provide clueson improving their functioning and resilience. This response is likely toinvolve mechanisms operating at different levels of ecologicalorganization. At the single-plant level, phenotypic changes can occur; atthe population level, spatial patterns can form; and at the communitylevel, community reassembly and biodiversity changes can occur.These mechanisms must affect one another, as stress relaxation byone mechanism weakens the driving forces of other mechanisms, butcomplex ecosystem responses involving coupled mechanisms havehardly been studied. In this talk I will focus on the interplay betweenphenotypic changes and spatial patterning and between spatialpatterning and community reassembly. Using mathematical models ofwater-limited plant communities, I will show that incorporatingphenotypic plasticity into vegetation pattern-formation theory canresolve two outstanding puzzles associated with the fascinatingNamibian fairy circle phenomenon and describe a predicted bufferingeffect of spatial patterning on community composition along rainfallgradients. Possible implications of these results to ecosystemfunctioning in stressed environments will be discussed.
    Lecture
  • Date:22SundayDecember 2024

    Making Climate Tech Work – Policies that Drive Innovation

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    Time
    13:00 - 14:00
    Location
    Nella and Leon Benoziyo Building for Plant and Environmental Sciences
    690
    LecturerProf. Alon Tal
    Host: Prof. Ron Milo, IES Director
    Organizer
    The Institute for Environmental Sustainability , Sustainability and Energy Research Initiative (SAERI)
    Contact
    Lecture
  • Date:22SundayDecember 2024

    The Clore Center for Biological Physics

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    Time
    13:15 - 14:30
    Title
    The harmonic three-body problem: from gauge field theory of falling cats to fractional rotational diffusion
    Location
    Nella and Leon Benoziyo Physics Library
    LecturerProf. Efi Efrati
    lunch will be served at 12:45
    Organizer
    Clore Center for Biological Physics
    Contact
    AbstractShow full text abstract about  In this talk I will present the study of the non-h...»
     In this talk I will present the study of the non-holonomic rotational dynamics of the classical harmonic three mass system in the strongly nonlinear regime. This is the simplest isolated spring-mass system capable of displaying rotation with zero angular momentum as well as chaotic dynamics. Combined together these two phenomena lead to a wide variety of qualitatively distinct dynamical phases as a function of the system's internal energy. For low energy, where dynamics are regular, we observe a constant rotation rate with zero angular momentum. For sufficiently high energy we observe a rotational random walk driven by the system's internal chaotic dynamics. For intermediate energies, we observe ballistic bouts of constant rotation rates interrupted by unpredictable orientation reversal events. In this regime, the system constitutes a simple physical model for Levy walks and the orientation reversal statistics lead to fractional rotational diffusion interpolating smoothly between the ballistic and regular diffusive regimes. FOR THE LATEST UPDATES AND CONTENT ON SOFT MATTER AND BIOLOGICAL PHYSICS AT THE WEIZMANN, VISIT OUR WEBSITE: https://www.biosoftweizmann.com/ 
    Lecture
  • Date:23MondayDecember 2024

    The Israel Rubinstein 4th Memorial Lecture -"The challenge of rechargeable batteries with very high energy density and prolonged cycle life: from basic science to practical devices"

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    Time
    11:00 - 12:00
    Location
    Gerhard M.J. Schmidt Lecture Hall
    LecturerProf. Doron Aurbach
    Bar Ilan University, Department of Chemistry
    Organizer
    Department of Molecular Chemistry and Materials Science
    Contact
    AbstractShow full text abstract about The development of high energy density, long running recharg...»
    The development of high energy density, long running rechargeable batteries like
    Li ion batteries, that power so successfully all mobile electronic devices, can be
    considered as the greatest success of modern electrochemistry.
    However, the basis for this success was the capability of exploring most complex
    electrodes, electrolyte solutions and reactive interfaces by most sophisticated
    electroanalytical tools in conjunction with advanced spectroscopic and microscopic
    was a first-rate leader in electroanalytical ז"ל techniques. Professor Israel Rubinstein
    chemistry. I learned a lot from him.
    The main theme of this presentation is to examine what is the true horizons for advanced
    high energy density batteries that can promote the electro-mobility revolution. The
    limiting factor in Li-ion batteries in terms of energy density, cost, potential, durability
    and cycling efficiency are the cathode materials used. We will examine most energetic
    cathode materials and novel approaches we developed for their stabilization. We
    describe in this lecture which electrode materials can be relevant, methodologies
    of their stabilization by doping, coating, and affecting electrodes surface chemistry
    by the use of active additives. Most important cathode materials are comprising the
    5 elements Li,Ni,Co,Mn,O at different stoichiometries that determine voltage and
    specific capacities. We will explain how the stoichiometry dictates basic cathodes
    properties.1,2 We will discuss the renaissance of Li metal-based rechargeable batteries.3
    We have learned how the stabilize Li metal anodes in rechargeable batteries using
    reactive electrolyte solutions that induce excellent passivation through controlled
    surface reactions. The emphasis is on fluorinated co-solvents that open the door for a
    very rich surface chemistry that forms passivating surface films that behave as ideal
    solid electrolyte interphase on both anodes and cathodes in advanced secondary Li
    batteries. This field provides fascinating examples how systematic basic scientific
    work leads to development of most practical devices for energy storage & conversion.
    Lecture
  • Date:23MondayDecember 2024

    Foundations of Computer Science Seminar

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    Time
    11:15 - 12:15
    Title
    On Cryptography and the Perebor Conjectures
    Location
    Jacob Ziskind Building
    Room 1 - 1 חדר
    LecturerNoam Mazor
    Tel Aviv University
    Organizer
    Department of Computer Science and Applied Mathematics
    Contact
    AbstractShow full text abstract about The Perebor (Russian for "brute-force search") con...»
    The Perebor (Russian for "brute-force search") conjectures are among the oldest conjectures in complexity theory. These conjectures, a stronger form of the P!=NP conjecture (which they predate), assert that for "meta-complexity" problems—such as the Time-Bounded Kolmogorov Complexity Problem and the Minimum Circuit Size Problem (MCSP)—no algorithms significantly outperform brute-force search.  

    In this talk, we will refute the non-uniform version of the Perebor conjecture for the Time-Bounded Kolmogorov Complexity Problem. Specifically, for every polynomial t(.), we will see a circuit of size 2^{4n/5+o(n)} that solves the t(.)-bounded Kolmogorov complexity problem on all instances.  Along the way, and of independent interest, we will extend the Fiat-Naor result, by showing that any efficiently computable function can be inverted by a circuit of size 2^{4n/5+o(n)}.

    Furthermore, we will show that, under cryptographic assumptions, Gap versions of meta-complexity problems are not NP-complete under Levin (witness-preserving) reductions. Finally, we will demonstrate how this barrier, combined with known NP-completeness results for meta-complexity problems, leads to a lower bound on the overhead of indistinguishability obfuscation (iO).  

    This talk is based on joint works with Zhenjian Lu, Igor C. Oliveira, and Rafael Pass.
    Lecture
  • Date:24TuesdayDecember 2024

    Winter STAR Workshop

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    Time
    10:00 - 18:00
    Location
    Jacob Ziskind Building
    1 & 155
    Lecture
  • Date:24TuesdayDecember 2024

    Anterior-Posterior Insula Circuit Mediates Retrieval of a Conditioned Immune Response in Mice

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    Time
    12:30 - 13:30
    Location
    Gerhard M.J. Schmidt Lecture Hall
    LecturerProf. Kobi Rosenblum
    Organizer
    Department of Brain Sciences
    Contact
    AbstractShow full text abstract about The brain can form associations between sensory information ...»
    The brain can form associations between sensory information of inner and/or outer world (e.g. Pavlovian conditioning) but also between sensory information and the immune system. The phenomenon which was described in the last century is termed conditioned immune response (CIR) but very little is known about neuronal mechanisms subserving it.  The conditioned stimulus can be a given taste and the unconditioned stimulus is an agent that induces or reduces a specific immune response.  Over the last years, we and others revealed molecular and cellular mechanisms underlying taste valance representation in the anterior insular cortex (aIC). Recently, a circuit in the posterior insular cortex (pIC) encoding the internal representation of a given immune response was identified. Together, it allowed us to hypothesize and prove that the internal reciprocal connections between the anterior and posterior insula encode CIR.  One can look at CIR as a noon declarative form of Nocebo effect and thus we demonstrate for the first time a detailed circuit mechanism for Placebo/Nocebo effect in the cortex.
    Lecture
  • Date:25WednesdayDecember 2024

    Winter STAR Workshop

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    Time
    10:00 - 18:00
    Location
    Jacob Ziskind Building
    1 & 155
    Lecture
  • Date:25WednesdayDecember 2024

    Machine Learning and Statistics Seminar

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    Time
    11:15 - 12:15
    Title
    Communal AI - Open, Collaborative & Accessible LLMs
    Location
    Jacob Ziskind Building
    Room 1 - 1 חדר
    LecturerLeshem Choshen
    MIT
    Organizer
    Department of Computer Science and Applied Mathematics
    Contact
    AbstractShow full text abstract about Developing better Language Models would benefit a myriad of ...»
    Developing better Language Models would benefit a myriad of communities. However, it is prohibitively costly. The talk would describe collaborative approaches to pretraining, such as model merging, which allows the combining of several specialized models into one. Then, it would introduce efficient evaluation to reduce overheads and touch on other accessible and collaborative aspects that best harness the expertise and diversity in Academia.
    Lecture
  • Date:26ThursdayDecember 2024

    An intimate meeting with the families of the hostages Tal Shoham and Yagev Buchshtab

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    Time
    09:45 - 11:15
    Location
    Nella and Leon Benoziyo Building for Biological Sciences
    Auditorium
    Organizer
    Department of Molecular Cell Biology
    Contact
    Cultural Events
  • Date:26ThursdayDecember 2024

    Winter STAR Workshop

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    Time
    10:00 - 18:00
    Location
    Jacob Ziskind Building
    1 & 155
    Lecture
  • Date:26ThursdayDecember 2024

    Foundations of Computer Science Seminar

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    Time
    10:15 - 11:45
    Title
    Algorithmic Contract Design
    Location
    Jacob Ziskind Building
    LecturerTomer Ezra
    Harvard
    Organizer
    Department of Computer Science and Applied Mathematics
    Contact
    AbstractShow full text abstract about We explore the framework of contract design through a comput...»
    We explore the framework of contract design through a computational perspective. Contract design is a fundamental pillar of microeconomics, addressing the essential question of how to incentivize people to work. The significance of contract design was acknowledged by the Nobel Prize awarded to Hart and Holmström, and it applies to various real-life scenarios, such as determining bonuses for employees, setting commission structures for sales representatives, and designing payment schemes for influencers promoting products.

    While contract design has been extensively studied from an economic perspective, this talk will examine it from a computational viewpoint. Specifically, we introduce combinatorial extensions of classic contract design models, where a principal delegates tasks to one or multiple agents. The agents have sets of potential actions they can take to complete the task, and the chosen actions by the agents stochastically determine the success of the task. We analyze the structure and computational aspects of these models, and present algorithms that provide (approximately) optimal guarantees.
    Lecture
  • Date:26ThursdayDecember 2024

    Vision and AI

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    Time
    12:15 - 13:15
    Title
    Discovering and Erasing Undesired Concepts
    Location
    Jacob Ziskind Building
    LecturerNiv Cohen
    NYU
    Organizer
    Department of Computer Science and Applied Mathematics
    Contact
    AbstractShow full text abstract about The rapid growth of generative models allows an ever-increas...»
    The rapid growth of generative models allows an ever-increasing variety of capabilities. Yet, these models may also produce undesired content such as unsafe images, private information, or copyrighted material.

    In this talk, I will discuss practical methods to prevent undesired generations. First, I will show how the challenge of avoiding undesired generations manifested itself in a simple Capture-the-Flag LLM setting, where even our top defense strategy was breached. Next, I will demonstrate a similar vulnerability in state-of-the-art concept erasure methods for Text-to-Image models. Finally, I will describe the notion of ‘Unconditional Concept Erasure’ aiming to mitigate such vulnerabilities. I will show that Task Vectors can achieve Unconditional Concept Erasure, and discuss the challenge of applying Task Vectors in practice.

    Bio: Niv is a postdoctoral researcher at New York University hosted by Prof. Chinmay Hegde. He received a BSc in mathematics with physics as part of the Technion Excellence Program. He received his PhD in computer science from the Hebrew University of Jerusalem, advised by Prof. Yedid Hoshen. Niv was awarded the Israeli data science scholarship for outstanding postdoctoral fellows (VATAT). He is interested in anomaly detection, model personalization, and AI safety for Vision
    Lecture
  • Date:26ThursdayDecember 2024

    Deep language models as a cognitive model for natural language processing in the human brain

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    Time
    12:30 - 13:30
    Location
    Gerhard M.J. Schmidt Lecture Hall
    LecturerProf. Uri Hasson
    Special Seminar
    Organizer
    Department of Brain Sciences
    Contact
    AbstractShow full text abstract about Naturalistic experimental paradigms in cognitive neuroscienc...»
    Naturalistic experimental paradigms in cognitive neuroscience arose from a pressure to test, in real-world contexts, the validity of models we derive from highly controlled laboratory experiments. In many cases, however, such efforts led to the realization that models (i.e., explanatory principles) developed under particular experimental manipulations fail to capture many aspects of reality (variance) in the real world. Recent advances in artificial neural networks provide an alternative computational framework for modeling cognition in natural contexts. In this talk, I will ask whether the human brain's underlying computations are similar or different from the underlying computations in deep neural networks, focusing on the underlying neural process that supports natural language processing in adults and language development in children. I will provide evidence for some shared computational principles between deep language models and the neural code for natural language processing in the human brain. This indicates that, to some extent, the brain relies on overparameterized optimization methods to comprehend and produce language. At the same time, I will present evidence that the brain differs from deep language models as speakers try to convey new ideas and thoughts. Finally, I will discuss our ongoing attempt to use deep acoustic-to-speech-to-language models to model language acquisition in children. 
    Lecture
  • Date:26ThursdayDecember 2024

    Exploring the role of pipecolic acid in Plasmodium falciparumnnounced

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    Time
    15:00 - 16:00
    Location
    Nella and Leon Benoziyo Building for Biological Sciences
    Cafeteria, floor 0
    LecturerSonia Oren
    Organizer
    Department of Biomolecular Sciences
    Contact
    AbstractShow full text abstract about Plasmodium falciparum (Pf) parasite is the major ca...»
    Plasmodium falciparum (Pf) parasite is the major cause of malaria disease, resulting in more than 600,000 deaths annually. Patients with cerebral malaria, the most severe form of malaria, show elevated plasma L-pipecolic acid (PA) concentrations in their blood compared to those with mild malaria. However, the origin and function of PA in Pf infection remain mostly elusive. Here, using LC/MS targeted metabolomics we found that the malaria parasite, while growing inside its host human Red Blood Cell (RBC), secretes PA during a specific life stage, the trophozoite. We then demonstrated that pretreatment of the host naïve human RBCs with PA significantly enhances parasitic growth. To further investigate the effect of PA on its primary host, RBCs, we measured the biophysical alterations in the pretreated naïve RBCs using atomic force microscopy combined with machine learning.  Surprisingly, we found that PA modifies the mechanical properties of the host cell’s membrane, turning it significantly softer. Electron paramagnetic resonance data on liposomes suggest that PA’s mechanism may involve altering the lipid mobility. Overall, our findings reveal that the parasite secretes PA to prime its host RBCs for invasion by inducing mechanical changes in the stiffness of the host membrane. These results indicate that PA functions as an active secreted metabolite, facilitating Pf growth within its host cell.
    Lecture
  • Date:29SundayDecember 2024

    Atmospheric stability sets extreme surface moist heat

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    Time
    11:00 - 12:00
    Location
    Sussman Family Building for Environmental Sciences
    M. Magaritz seminar room
    LecturerTalia Tamarin-Brodsky
    Contact
    AbstractShow full text abstract about Heatwaves have been extensively studied in the past, primari...»
    Heatwaves have been extensively studied in the past, primarily from the standpoint of heatwave formation.Previous studies have identified air subsidence, diabatic heating, and warm air advection as the primary mechanisms for heat accumulation at the surface. However, less workhas focused on what leads to eatwave termination. A recent study suggests that surface temperature can onlyincrease until convection is triggered, and thus proposed a theoretical upper bound of maximum surface airtemperature, assuming a neutrally buoyant atmosphere and a dry surface. Given that most midlatitude heatwave events involve moist surface conditions, which also support theaccumulation of Convective Available Potential Energy (CAPE), we propose an alternative theory that quantifieschanges in surface moist temperature while correctly accounting for the buildup of CAPE. We show that the lower free tropospheric inversion predicts the maximum intensity ofboth moist heat and moist convection in midlatitudes. Implications for heatwave evolution and projected future changes in extreme moist heat events are discussed.
    Lecture
  • Date:29SundayDecember 2024

    Perceptual decision coding is inherently coupled to action in the mouse cortex

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    Time
    12:00 - 13:15
    Location
    Max and Lillian Candiotty Building
    Auditorium
    LecturerMichael Sokoletsky PhD Defense
    Student Seminar-PhD Thesis Defense
    Organizer
    Department of Brain Sciences
    Contact
    AbstractShow full text abstract about How do animals make perceptual decisions about sensory stimu...»
    How do animals make perceptual decisions about sensory stimuli to guide motor actions? One hypothesis is that dedicated "perceptual decision" cells process sensory information and drive the appropriate action. Alternatively, perceptual decisions result from competition among cells driving different actions, making decisions inherently coupled to actions. To distinguish between these hypotheses, we designed a vibrotactile detection task in which mice flexibly switched between standard and reversed contingency blocks, respectively requiring them to lick after stimulus presence or absence. Optogenetic inactivation of somatosensory and secondary motor cortices reduced stimulus sensitivity without impairing the ability to lick. However, widefield and two-photon imaging found that differences in cortical activity across perceptual decisions were almost exclusively action-coupled. In addition, we identified a subset of cells that encoded the current contingency block in a gated manner, enabling mice to flexibly make decisions without relying on action-independent decision coding.
    Lecture
  • Date:30MondayDecember 2024

    Hierarchical Design Principles for Multifunctional Biocomposites

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    Time
    10:00 - 11:00
    Location
    Schmidt Lecture Hall
    LecturerDr. Israel Kellersztein
    Lecture
  • Date:30MondayDecember 2024

    Foundations of Computer Science Seminar

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    Time
    11:15 - 12:15
    Title
    Can We Bypass the Curse of Dimensionality in Private Data Analysis?
    Location
    Jacob Ziskind Building
    Room 1 - 1 חדר
    LecturerEliad Tsfadia
    Georgetown University
    Organizer
    Department of Computer Science and Applied Mathematics
    Contact
    AbstractShow full text abstract about Differentially private (DP) algorithms typically exhibit a s...»
    Differentially private (DP) algorithms typically exhibit a significant dependence on the dimensionality of their input, as their error or sample complexity tends to grow polynomially with the dimension. This cost of dimensionality is inherent in many problems, as Bun, Ullman, and Vadhan (STOC 2014) showed that any method that achieves lower error rates is vulnerable to tracing attacks (also known as membership inference attacks). Unfortunately, such costs are often too high in many real-world scenarios, such as training large neural networks, where the number of parameters (the ambient dimension) is very high.

    On the positive side, the lower bounds do not rule out the possibility of reducing error rates for "easy" inputs. But what constitutes "easy" inputs? And how likely is it to encounter such inputs in real-world scenarios?
    In this talk, I will present a few ways to quantify "input easiness" for the fundamental task of private averaging and support them with upper and lower bounds. In particular, I will show types of properties that are both sufficient and necessary for eliminating the polynomial dependency on the dimension.

    I will conclude by outlining future research directions and providing a broader perspective on my work.

    The talk is mainly based on the following three papers:

    (1) FriendlyCore https://arxiv.org/abs/2110.10132 (joint with Edith Cohen, Haim Kaplan, Yishay Mansour, and Uri Stemmer, ICML 2022),
    (2) https://arxiv.org/abs/2307.07604 (joint with Naty Peter and Jonathan Ullman, COLT 2024),
    (3) https://arxiv.org/abs/2402.06465 (NeurIPS 2024)
    Lecture
  • Date:31TuesdayDecember 2024

    Special Guest Seminar, Dr. Neta Gazit Shimoni

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    Time
    10:00 - 11:00
    Title
    Molecular and Cell Biology, University of California at Berkeley
    Location
    Belfer Building, Botnar Auditorium
    Lecturer“Neuropeptides as Modulators of Synaptic Function and Behavior in Rodents”
    Lecture

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