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דצמבר 01, 2013
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Date:09חמישיינואר 2014הרצאה
Carrier-envelope phase control over molecular dynamics in strong-field laser pulses
More information שעה 11:15 - 12:30מיקום בניין הפיזיקה ע"ש עדנה וק.ב. וייסמןמרצה ITZIK BEN-ITZHAK
Kansas State Universityמארגן הפקולטה לפיזיקהצרו קשר תקציר Show full text abstract about We have studied strong-field laser-induced fragmentation of ...» We have studied strong-field laser-induced fragmentation of the benchmark hydrogen molecule in sub 5 fs near infrared (IR) pulses. As the pulse duration approaches a single cycle, the molecular response depends on the waveform of the pulse. For a particularly simple example of the waveform which is characterized by the carrier-envelope phase (CEP) – the CEP can be used as a control knob for the ensuing molecular dynamics.
In this kind of experiments a “CEP-locking” or “CEP-tagging” technique is typically employed. The latter method was used in our studies as demonstrated in this talk by two examples. The first involves the study of CEP control over pathway interference in strong-field dissociation of H2+ [1,2], where a molecular-ion beam was used as the target. In the second example we explore the formation of long-lived excited H fragments from the fragmentation of an H2 target. As predicted by theory [3,4], the measurements show that the CEP steers protons of H2+ (or excited-hydrogen fragments H2) one way or the other along the laser polarization. Moreover, the fragmentation yield itself depends on the CEP.
Others contributing to this work:
N.G. Johnson, M. Zohrabi, B. Berry, U. Ablikim, B. Jochim, T. Severt, K. J. Betsch, K.D. Carnes,
Shuo Zeng, F. Anis, J. Hernández, Yujun Wang, and B.D. Esry
1Supported by the Chemical Sciences, Geosciences and Biosciences Division, Office of Basic Energy Sciences, Office of Science, US Department of Energy
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Date:09חמישיינואר 2014הרצאה
What color is the sky?
More information שעה 12:00 - 12:00מיקום בניין יעקב זיסקינדמרצה Yair Weiss
Hebrew University of Jerusalemמארגן הפקולטה למתמטיקה ומדעי המחשבצרו קשר -
Date:09חמישיינואר 2014אירועי תרבות
צחוק הגורל עו"ד בני דון יחייא
More information שעה 21:00 - 21:00כותרת תולדות ההומור היהודימיקום אולם ע"ש דולפי ולולה אבנרצרו קשר -
Date:12ראשוןינואר 201417שישיינואר 2014כנסים
Black Holes and Quantum Information Theory
More information שעה 08:00 - 15:00מיקום מרכז כנסים על-שם דויד לופאטייושב ראש Micha Berkoozצרו קשר -
Date:12ראשוןינואר 2014הרצאה
Critical and gradual transitions in pattern-forming systems
More information שעה 11:00 - 11:00מיקום בניין משפחת זוסמןמרצה Dr. Golan Bel
Department of Solar Energy and Environmental Physics Blaustein Institutes for Desert Research Ben Gurion University of the Negevמארגן המחלקה למדעי כדור הארץ וכוכבי הלכתצרו קשר תקציר Show full text abstract about Critical transitions have attracted a great deal of attentio...» Critical transitions have attracted a great deal of attention due to their relevance to many natural and
social systems. Much research has been devoted to the characterization and identification of imminent
critical transitions. In spatially extended systems, the dynamics (close to and away from the critical
point) is more complicated due to the expansion, shrinking and coalescence of alternative-state
domains. Pattern-forming systems introduce additional complexity due to the patterned nature of one of
the stable states. In this talk, I will present several works in which we used the context of drylands
vegetation dynamics to study various aspects of this additional complexity: (i) Using a minimal model,
we showed that in systems exhibiting a bistability of a patterned state with a uniform state, a multitude
of intermediate stable localized states may appear, giving rise to step-like gradual shifts with extended
pauses at these states. This result suggests that a combination of abrupt-shift indicators and
gradual-shift indicators might be needed to unambiguously identify regime shifts. (ii) The existence of
these localized states in models for the dynamics of drylands vegetation and the response of the
systems described by these models to local perturbations will be discussed. (iii) We show how a
simplified version of a model for drylands vegetation dynamics can explain the emergence and the
observed dynamics of the spectacular phenomenon of “fairy circles” in southern Africa. If time
permits, I will present recent results demonstrating the effects of heterogeneity on the pattern
formation, survivability and resilience of water-limited vegetation.
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Date:12ראשוןינואר 2014הרצאה
The Euclid Space mission
More information שעה 11:15 - 12:00מיקום בניין לפיזיקה על-שם נלה וליאון בנוזיומרצה Andrea Cimatti מארגן מרכז לאסטרופיסיקה עש נלה וליאון בנוזיוצרו קשר -
Date:12ראשוןינואר 2014הרצאה
To be announced
More information שעה 13:00 - 13:00מיקום בניין ארתור ורושל בלפר למחקר ביורפואימרצה Tomer Stern
Elazar Zelzer's group, Dept. of Molecular Genetics, WISצרו קשר -
Date:12ראשוןינואר 2014הרצאה
Boltzmann's Dog and Darwin's Finch: The statistical thermodynamics of self-replication and evolution
More information שעה 13:15 - 13:15מיקום מעבדה על-שם דני נ. היינמןמרצה Prof. Jeremy England
Dept. of Physics MITמארגן מרכז לפיזיקה ביולוגית עש קלורצרו קשר תקציר Show full text abstract about Living things operate according to well-known physical laws,...» Living things operate according to well-known physical laws, yet it is challenging to discern specific, non-trivial consequences of these constraints for how an organism that is a product of evolution must behave. Part of the difficulty here is that life lives very far from thermal equilibrium, where many of our traditional theoretical tools fail us. However, recent developments in nonequilibrium statistical mechanics may help light a way forward. The goal of this talk will be to explain some of these developments, and show how they offer a new perspective on the physics of self-replication, natural selection, and evolution. -
Date:12ראשוןינואר 2014הרצאה
The role of neutrophil infiltration for indcution of hepatic insulin resistance early in the course of High fat feeding
More information שעה 15:00 - 16:00מיקום בניין ארתור ורושל בלפר למחקר ביורפואימרצה Prof. Rachel Levy
Faculty of Health Sciences, Soroka University Medical Center and Ben-Gurion University of the Negevצרו קשר -
Date:13שניינואר 2014הרצאה
Adsorption of specially designed molecules on ionic substrates
More information שעה 10:00 - 10:00מיקום בניין פרלמן למדעי הכימיהמרצה Prof. Alex Shluger
Department of Physics and Astronomy, University College London, UKמארגן המחלקה לכימיה מולקולרית ולמדע חומריםצרו קשר -
Date:13שניינואר 2014הרצאה
Clean nuclear-energ and climate-change
More information שעה 11:15 - 12:00מיקום בניין לפיזיקה על-שם נלה וליאון בנוזיומרצה Frank Shu מארגן מרכז לאסטרופיסיקה עש נלה וליאון בנוזיוצרו קשר תקציר Show full text abstract about We take a first principles approach to the science of climat...» We take a first principles approach to the science of climate change
and sustainable energy. We examine why carbon dioxide and
methane are worrisome greenhouse gases (GHG) despite being minor constituents
of the Earth's atmosphere, why the increase of extreme climate-related events is
exponentially sensitive to seemingly small increases in the mean temperature
of the surface of the Earth, and why it is so hard to displace fossil fuels
as the sources of primary energy generation by current clean-energy technologies.
We argue that climate mitigation now requires not only emitting less GHG,
but actually sources of negative carbon. We then present two technologies
researched by our group, supertorrefiers (STRs) and molten salt breeder reactors
(MSBRs), that taken together can result in a systematic lowering of GHG levels in
the Earth's atmosphere. STRs have the potential of creating solid, liquid, and gaseous
biofuels that are economically competitive with coal, petroleum, and natural gas.
MSBRs can replace, over the long-term, the light water reactors in current usage
with a walk-away safe, less expensive, more proliferation-resistant form of nuclear power,
with acceptable solutions for the problems of high-level and low-level nuclear waste.
Taken together, STRs and MSBRs allow a smooth and gradual transition away from fossil fuels
while exploiting the storage, transportation, and power-generation infrastructures
built up to support the fossil-fuel industry in a manner which can improve (if the biochar
is buried instead of burned), rather than degrade, the environment with increased use. -
Date:13שניינואר 2014הרצאה
QIIME: Quantitative Insights Into Microbial Ecology
More information שעה 14:15 - 16:00מיקום בניין ארתור ורושל בלפר למחקר ביורפואימרצה Prof. Rob Knight
Department of Chemistry and Biochemistry. University of Coloradoמארגן הפקולטה לביולוגיהצרו קשר -
Date:13שניינואר 2014הרצאה
Understanding the variability of growth in single cells
More information שעה 14:15 - 14:15מיקום בניין הפיזיקה ע"ש עדנה וק.ב. וייסמןמרצה Nathalie Balaban
HUJIמארגן המחלקה לפיזיקה של מערכות מורכבותצרו קשר תקציר Show full text abstract about Noise analysis in biological systems has greatly increased o...» Noise analysis in biological systems has greatly increased our understanding of the underlying cellular processes. Noise in the cell division process is often assumed to be responsible for variability in cell cycle duration, and to underlie heterogeneous responses of bacteria to antibiotics, as well as of cancer cells to drugs. We present a simple genetic module, known as a toxin-antitoxin motif, which exploits noise to generate a variability of growth in bacterial populations. More generally, we ask whether we can differentiate between stochastic and deterministic control of cell division variability. Using long-term time lapse microscopy to follow thousands of divisions and tools from non linear dynamics analysis, we show that the variability in cell-cycle duration in mammalian cells, which at first glance seems dominated by noise, is in fact controlled by a deterministic factor
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Date:13שניינואר 2014הרצאה
מפגשים בחזית המדע
More information שעה 19:30 - 21:15מיקום מכון דוידסון לחינוך מדעימארגן יחידת שוהם במכון דוידסוןדף בית צרו קשר -
Date:14שלישיינואר 2014הרצאה
The mechanobiology of cell adhesion
More information שעה 10:00 - 11:00מיקום בניין וולפסון למחקר ביולוגימרצה Prof. Benny Geiger
Dept. of Molecular Cell Biology - WISמארגן המחלקה למדעים ביומולקולרייםצרו קשר -
Date:14שלישיינואר 2014הרצאה
Gut microbes and their role in obesity and malnutrition
More information שעה 10:00 - 10:00מיקום בניין ארתור ורושל בלפר למחקר ביורפואימרצה Prof. Rob Knight
Department of Chemistry and Biochemistry. University of Coloradoמארגן הפקולטה לביולוגיהצרו קשר -
Date:14שלישיינואר 2014סימפוזיונים
Life Sciences Colloquium
More information שעה 11:00 - 11:00כותרת Mapping Developmental Pathways for Regenerative Medicine via Synthetic Modified mRNAמיקום אולם ע"ש דולפי ולולה אבנרמרצה Prof. Kenneth Chien צרו קשר -
Date:14שלישיינואר 2014הרצאה
“FLP Mediated Reduction of CO2, CO and Flouroalkanes”
More information שעה 11:00 - 11:00כותרת Organic Chemistry - Departmental Seminarמיקום בניין הלן ומילטון קימלמןמרצה Dr. Roman Dobrovetsky
Department of Chemistry University of Torontoמארגן המחלקה לכימיה מולקולרית ולמדע חומריםצרו קשר תקציר Show full text abstract about Frustrated Lewis pairs (FLPs) are sterically encumbered Lew...» Frustrated Lewis pairs (FLPs) are sterically encumbered Lewis acid/base combinations which do not form adducts, but successfully activate small molecules such as H2, CO2, N2O, NO etc. Recently, few examples of catalytic hydrogenation and hydroamination were shown employing FLP chemistry. However, despite this recent progress, the synthetic use of FLPs is still in its infancy.
In this talk some recent advancement of FLP chemistry will be presented e.g., a) catalytic reduction of CO2 to CO; b) Reduction of CO in CO/H2 mixture (analog of Fischer–Tropsch chemistry); c) Catalytic hydrodeflourination of flouroalkanes using Lewis acidic phosphonium.
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Date:14שלישיינואר 2014הרצאה
"Studying the evolutionary constraints on metabolic pathway design"
More information שעה 11:15 - 11:15מיקום בניין אולמן למדעי החייםמרצה Dr. Elad Noor
Dr. Ron Milo's lab, Plant Sciences Dept., Weizmann Institute of Scienceמארגן המחלקה למדעי הצמח והסביבהצרו קשר -
Date:14שלישיינואר 2014הרצאה
Restoration of Sight with Photovoltaic Retinal Prosthesis
More information שעה 12:30 - 12:30מיקום אולם הרצאות ע"ש גרהרד שמידטמרצה Dr. Yossi Mandel, MD, PhD, MHA
Ophthalmic Sciences and Engineering Lab Faculty of Life Sciences Bar Ilan Universityמארגן המחלקה למדעי המוחצרו קשר תקציר Show full text abstract about Retinal degenerative diseases, such as Retinitis Pigmentosa ...» Retinal degenerative diseases, such as Retinitis Pigmentosa (RP) and Age related Macular Degeneration (AMD), lead to loss of sight due to degeneration of photoreceptors, yet the inner retinal neurons which process the visual signals and relay them to the brain are relatively well preserved. Patterned electrical stimulation of the inner retinal neurons can elicit patterned visual perception, thereby restoring sight to some degree, as was demonstrated in recent clinical trials. However, current RF-powered implants require bulky electronics and trans-scleral cables, making implantation very complex and prone to failures. Even more importantly, low visual acuity achieved with the current implants limits their applicability to very small fraction of patients.
We have developed a wireless photovoltaic retinal prosthesis, in which camera-captured images are projected onto the retina using pulsed near-IR light. Each pixel in the subretinal implant directly converts pulsed light into local electric current to stimulate the nearby inner retinal neurons. Implants with pixel sizes of 280, 140 and 70µm were successfully implanted in the subretinal space of wild type and degenerate rats, and elicited robust cortical responses (eVEP) upon stimulation with NIR light. Amplitude of the eVEP increased with peak irradiance and pulse duration, and decreased with frequency in the range of 2-20Hz, similar to the visible light response.
Modular design of the arrays allows scalability to a large number of pixels, and combined with the ease of implantation, offers a promising approach to restoration of sight in patients blinded by retinal degenerative diseases.
Activation of the retinal bipolar cells by the implant makes our model a unique tool for studying retinal circuitry by comparing the response to stimuli elicited by the subretinal implant to those naturally elicited by visible light. I will discuss our novel approach to quantitative assessment of the visual acuity provided by the implant, as well as some unique aspects of prosthetic vision, such as stroboscopic stimulation. The theoretical and practical limits of visual acuity will be discussed along with future directions for restoration of sight to the blind.