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ספטמבר 12, 2011
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Date:26שנינובמבר 2012הרצאה
Measurement of Transparency Ratios for Protons from Short-Range Correlated Pairs
More information שעה 14:45 - 15:45מיקום בניין הפיזיקה ע"ש עדנה וק.ב. וייסמןמרצה Or Hen
Tel Aviv Universityמארגן המחלקה לפיזיקה של חלקיקים ואסטרופיזיקהצרו קשר תקציר Show full text abstract about Nuclear transparency, Tp(A), is a measure of the average pro...» Nuclear transparency, Tp(A), is a measure of the average probability for a struck proton to escape the nucleus without further interaction. It is usually defined as the ratio of the measured quasi-elastic A(e,e'p) cross section to a calculation that assumes no final state interactions (FSI). Nuclear transparencies were extracted for mean field protons, below the Fermi sea level, where the spectral functions are well known.
In this talk I will present a novel observable, the transparency ratios, Tp(A)/Tp(12C), for knockout of high-missing-momentum protons from the breakup of Short Range Correlated pairs (2N-SRC) in 27Al, 56Fe and 208Pb nuclei relative to 12C. The ratios were measured at large Q2 and xB>1.2 where the reaction is dominated by scattering off 2N-SRC. The transparency ratios of the knocked-out (leading) protons coming from 2N-SRC breakup are 20-30% lower than those of mean field protons and are in better agreement with Glauber calculations. The new transparencies scale as A-1/3, which is consistent with scattering from nucleons at the nuclear surface. Conditioned transparency ratios for recoiling protons from A(e,e'pp) scattering are consistent with unity, evidence of the low FSI of the recoil nucleon with the A-2 system. This analysis is part of a data mining initiative that will be described in the talk.
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Date:26שנינובמבר 2012הרצאה
New Approach to the Investigation of Nuclei
More information שעה 16:15 - 17:15מיקום בניין הפיזיקה ע"ש עדנה וק.ב. וייסמןמרצה E. G. Drukarev
Petersburg Nuclear Physics Institute, Gatchina,St. Petersburg, Russiaמארגן המחלקה לפיזיקה של חלקיקים ואסטרופיזיקהצרו קשר תקציר Show full text abstract about Our approach is based on extension of the QCD (Quantum Chrom...» Our approach is based on extension of the QCD (Quantum Chromodynamics) sum rules (SR) method to systems with finite density of the baryon quantum number. It is based on the dispersion relations for the function, describing the system which carries the quantum numbers of the hadron. Exchange by the strongly correlated quark systems (mesons) is expressed in terms of exchange by the system of weakly interacting quarks with the same quantum numbers. The nucleon self-energies are obtained without employing a controversial conception of interaction between point-like nucleons. The calculation does not involve phenomenological parameters.
Application of the approach enables to express such characteristics of nucleon in nuclear matter as the Dirac effective mass m* and the vector self energy Sigma in terms of the density dependent QCD condensates. The condensates of the lowest dimension d=3 are the most important ones. These are the vector and the scalar quark condensate. The vector condensate is exactly proportional to the density due to conservation of the vector current. The linear part of the scalar condensate is presented in terms of the pion-nucleon sigma term, which can be expressed through the amplitude of the pion-nucleon elastic scattering. The most important next-to-leading condensates of dimension d=4 are expressed through the moments of the proton deep inelastic structure functions. Thus the most important density-dependent condensates are either calculated or related to observables. As a result, we find m* ~ -600 MeV, Sigma ~ 300 MeV at the phenomenological saturation value of density, in agreement with the results of the standard nuclear physics. We obtain also the density dependence of these characteristics.
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Date:26שנינובמבר 2012הרצאה
New Approach to the Investigation of Nuclei
More information שעה 16:15 - 17:15מיקום בניין הפיזיקה ע"ש עדנה וק.ב. וייסמןמרצה E. G. Drukarev
Petersburg Nuclear Physics Institute, Gatchina,St. Petersburg, Russiaמארגן המחלקה לפיזיקה של חלקיקים ואסטרופיזיקהצרו קשר תקציר Show full text abstract about Our approach is based on extension of the QCD (Quantum Chrom...» Our approach is based on extension of the QCD (Quantum Chromodynamics) sum rules (SR) method to systems with finite density of the baryon quantum number. It is based on the dispersion relations for the function, describing the system which carries the quantum numbers of the hadron. Exchange by the strongly correlated quark systems (mesons) is expressed in terms of exchange by the system of weakly interacting quarks with the same quantum numbers. The nucleon self-energies are obtained without employing a controversial conception of interaction between point-like nucleons. The calculation does not involve phenomenological parameters.
Application of the approach enables to express such characteristics of nucleon in nuclear matter as the Dirac effective mass m* and the vector self energy Sigma in terms of the density dependent QCD condensates. The condensates of the lowest dimension d=3 are the most important ones. These are the vector and the scalar quark condensate. The vector condensate is exactly proportional to the density due to conservation of the vector current. The linear part of the scalar condensate is presented in terms of the pion-nucleon sigma term, which can be expressed through the amplitude of the pion-nucleon elastic scattering. The most important next-to-leading condensates of dimension d=4 are expressed through the moments of the proton deep inelastic structure functions. Thus the most important density-dependent condensates are either calculated or related to observables. As a result, we find m* ~ -600 MeV, Sigma ~ 300 MeV at the phenomenological saturation value of density, in agreement with the results of the standard nuclear physics. We obtain also the density dependence of these characteristics.
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Date:26שנינובמבר 2012הרצאה
מפגשים בחזית המדע
More information שעה 19:15 - 21:00מיקום מכון דוידסון לחינוך מדעימארגן יחידת שוהם במכון דוידסוןדף בית צרו קשר -
Date:27שלישינובמבר 2012הרצאה
"Circadian Clocks & Polyamines: A Novel Metabolic Feedback Loop."
More information שעה 10:00 - 10:30מיקום בניין וולפסון למחקר ביולוגימרצה Ziv Zwighaft, WIS-Department of Biological Chemistry מארגן המחלקה למדעים ביומולקולרייםצרו קשר -
Date:27שלישינובמבר 2012הרצאה
"The molecular basis of phosphate discrimination in arsenate rich environments”
More information שעה 10:30 - 11:00מיקום בניין וולפסון למחקר ביולוגימרצה Mikael Elias
WIS-Department of Biological Chemistryמארגן המחלקה למדעים ביומולקולרייםצרו קשר -
Date:27שלישינובמבר 2012הרצאה
Adaptive Control of a Nonlinear Output, with an Application to Wind-Turbine Control
More information שעה 11:00 - 11:00מיקום בניין יעקב זיסקינדמרצה Yoav Sharon
MITמארגן הפקולטה למתמטיקה ומדעי המחשבצרו קשר -
Date:27שלישינובמבר 2012הרצאה
"Organic-based Magnets: New Chemistry and New Materials for this Millennium"
More information שעה 11:00 - 11:00כותרת Department Of Organic Chemistry - Departmental Seminarמיקום בניין הלן ומילטון קימלמןמרצה Prof. Joel S. Miller
Department of Chemistry, University of Utah, Salt Lake Cityמארגן המחלקה לכימיה מולקולרית ולמדע חומריםצרו קשר תקציר Show full text abstract about Organic-based materials exhibiting the technologically impor...» Organic-based materials exhibiting the technologically important property of bulk magnetism have been prepared and studied in collaboration with many research groups worldwide frequently exhibit supramolecular extended 3-D structures. These magnets are prepared via conventional organic synthetic chemistry methodologies, but unlike classical inorganic-based magnets do not require high-temperature metallurgical processing. Furthermore, these magnets are frequently soluble in conventional solvents (e. g., toluene, dichloromethane, acetonitrile, THF) and have saturation magnetizations more than twice that of iron metal on a mole basis, as well as in some cases coercive fields exceeding that of all commercial magnets (e.g., Co5Sm). Also several magnets with critical temperatures (Tc) exceeding room temperature have been prepared. In addition to an overview of magnetic behavior, numerous examples of structurally characterized magnets made from molecules will be presented. Our groups has discovered 8 families of molecule-based magnets, mostly organic-based, and have significantly contributed to an eight family based upon the Prussian blue structure. Four examples magnetically order above room temperature and as high at 127 oC. These will include [MIII(C5Me5)2][A], [MnIII(porphyrin)][A] (A = cyanocarbon etc. electron acceptors) as well as M[TCNE]x, which for M = V is a room temperature magnet that can be fabricated as a thin film magnet via Chemical Vapor Deposition (CVD) techniques. A newer class of magnets of [Ru2(O2CR)4]3[M(CN)6] (M = Cr, Fe; R = Me, t-Bu) composition will also discussed. For R = Me an interpenetrating, cubic (3-D) lattice forms and the magnet exhibits anomalous hysteresis, saturation magnetization, out-of-phase, "(T), AC susceptibility, and zero field cooled-field cooled temperature-dependent magnetization data. This is in contrast to R = t-Bu, which forms a layered (2-D) lattice. Additionally, new magnets possessing the nominal Prussian blue composition, M'[M(CN)6]x and (Cation)yM'[M(CN)6], but not their structure, will be described. The organic chemistry crucial to designing and preparing organic-based magnets will be discussed.
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Date:27שלישינובמבר 2012הרצאה
"Mechanisms, rates and specificities in grass genome instability"
More information שעה 11:15 - 11:15מיקום בניין ארתור ורושל בלפר למחקר ביורפואימרצה Prof. Jeffrey (Jeff) Bennetzen
Davison Life Sciences Complex, Department of Genetics, University of Georgia, Athens – GA, USAמארגן המחלקה למדעי הצמח והסביבהצרו קשר -
Date:27שלישינובמבר 2012הרצאה
What can parasitoid wasps teach us about decision making in the brain of insects?
More information שעה 12:30 - 12:30מיקום אולם הרצאות ע"ש גרהרד שמידטמרצה Prof. Frederic Libersat
Life Sciences Dept, Ben Gurion University of the Negev, Beer Shevaמארגן המחלקה למדעי המוחצרו קשר תקציר Show full text abstract about Much like humans, animals may choose to initiate behavior ba...» Much like humans, animals may choose to initiate behavior based on their "internal state" rather than as a response to external stimuli alone. The neuronal underpinnings responsible for generating this ‘internal state’, however, remain elusive. The parasitoid jewel wasp hunts cockroaches to serve as a live food supply for its offspring. The wasp stings the cockroach in the head and delivers a neurotoxic venom cocktail directly inside the prey’s cerebral ganglia to apparently ‘hijack its free will’. Although not paralyzed, the stung cockroach becomes a living yet docile ‘zombie’ incapable of self-initiating walking or escape running.
We demonstrate that the venom selectively depresses the cockroach’s motivation or ‘drive’ to initiate and maintain walking-related behaviors, rather than inducing an overall decrease in arousal or a ‘sleep-like’ state. Such a decrease in the drive for walking can be attributed to a decrease in neuronal activity in a small region of the cockroach cerebral nervous system, the sub-esophageal ganglion (SEG). Specifically, we have used behavioral, neuro-pharmacological and electrophysiological methods to show that artificial focal injection of crude milked venom or procaine into the SEG of non-stung cockroaches decreases spontaneous and evoked walking, as seen with naturally-stung cockroaches. Moreover, spontaneous and evoked neuronal spiking activity in the SEG, recorded with an extracellular bipolar microelectrode, is markedly decreased in stung cockroaches as compared with non-stung controls. By injecting a venom cocktail directly into the SEG, the parasitoid Jewel Wasp selectively manipulates the cockroach’s motivation to initiate walking without interfering with other non-related behaviors.
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Date:27שלישינובמבר 2012הרצאה
"The tails of p63 or 2 inactive 4 destruction"
More information שעה 14:00 - 15:00מיקום אולם הרצאות ע"ש גרהרד שמידטמרצה Prof. Volker Doetsch
Institute of Biophysical Chemistry, Goethe University Frankfurt/Germanyמארגן המחלקה לביולוגיה מבנית וכימיתצרו קשר -
Date:27שלישינובמבר 2012אירועי תרבות
"ממזרח למערב"
More information שעה 20:30 - 20:30כותרת טילדה רג'ואןמיקום אודיטוריום מיכאל סלעצרו קשר -
Date:28רביעינובמבר 2012הרצאה
On representations of affine Lie superalgebras
More information שעה 11:00 - 11:00מיקום בניין יעקב זיסקינדמרצה Prof. Maria Gorelik
מארגן הפקולטה למתמטיקה ומדעי המחשבצרו קשר -
Date:28רביעינובמבר 2012הרצאה
Spotlight on Science
More information שעה 12:00 - 13:30כותרת Harnessing DNA Repair for Lung Cancer Prevention and Early Detectionמיקום אולם הרצאות ע"ש גרהרד שמידטמרצה Dr. Tamar Paz-Elizur
Department of Biological Chemistryצרו קשר -
Date:28רביעינובמבר 2012אירועי תרבות
שלישיית יובל
More information שעה 12:30 - 13:30כותרת מינחה מוזיקליתמיקום אודיטוריום מיכאל סלעצרו קשר -
Date:29חמישינובמבר 201202שבתפברואר 2013אירועי תרבות
יונה ונער
More information שעה כל היוםכותרת עיבוד ראשון לרומן רב המכר מאת מאיר שלו.מיקום אודיטוריום מיכאל סלעצרו קשר -
Date:29חמישינובמבר 2012הרצאה
Biomedical super-resolved sensing
More information שעה 12:00 - 12:00מיקום בניין יעקב זיסקינדמרצה Zeev Zalevsky
Bar-Ilan Universityמארגן הפקולטה למתמטיקה ומדעי המחשבצרו קשר -
Date:29חמישינובמבר 2012הרצאה
Life Science Lecture
More information שעה 15:00 - 16:00כותרת From letters to function: Cracking the code of gene regulationמיקום אולם ע"ש דולפי ולולה אבנרמרצה Prof. Eran Segal
Department of Computer Science and Applied Mathematicsצרו קשר -
Date:30שישינובמבר 2012אירועי תרבות
"חתונה יהודית"
More information שעה 11:00 - 13:00כותרת דר' רוחמה אלבגמיקום אולם ע"ש דולפי ולולה אבנרצרו קשר -
Date:02ראשוןדצמבר 201206חמישידצמבר 2012כנסים
FUNTRAP12- ISF Conference on Fundamental Interactions with Atom and Ion Traps
More information שעה כל היוםמיקום בניין הפיזיקה ע"ש עדנה וק.ב. וייסמןיושב ראש Michael Hassדף בית צרו קשר
