Pages

ספטמבר 12, 2011

  • Date:26שנינובמבר 2012

    Measurement of Transparency Ratios for Protons from Short-Range Correlated Pairs

    More information
    שעה
    14:45 - 15:45
    מיקום
    בניין הפיזיקה ע"ש עדנה וק.ב. וייסמן
    מרצהOr Hen
    Tel Aviv University
    מארגן
    המחלקה לפיזיקה של חלקיקים ואסטרופיזיקה
    צרו קשר
    תקצירShow 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.
    הרצאה
  • Date:26שנינובמבר 2012

    New Approach to the Investigation of Nuclei

    More information
    שעה
    16:15 - 17:15
    מיקום
    בניין הפיזיקה ע"ש עדנה וק.ב. וייסמן
    מרצהE. G. Drukarev
    Petersburg Nuclear Physics Institute, Gatchina,St. Petersburg, Russia
    מארגן
    המחלקה לפיזיקה של חלקיקים ואסטרופיזיקה
    צרו קשר
    תקצירShow 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.
    הרצאה
  • Date:26שנינובמבר 2012

    New Approach to the Investigation of Nuclei

    More information
    שעה
    16:15 - 17:15
    מיקום
    בניין הפיזיקה ע"ש עדנה וק.ב. וייסמן
    מרצהE. G. Drukarev
    Petersburg Nuclear Physics Institute, Gatchina,St. Petersburg, Russia
    מארגן
    המחלקה לפיזיקה של חלקיקים ואסטרופיזיקה
    צרו קשר
    תקצירShow 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.
    הרצאה
  • Date:26שנינובמבר 2012

    מפגשים בחזית המדע

    More information
    שעה
    19:15 - 21:00
    מיקום
    מכון דוידסון לחינוך מדעי
    מארגן
    יחידת שוהם במכון דוידסון
    דף בית
    צרו קשר
    הרצאה
  • Date:27שלישינובמבר 2012

    "Circadian Clocks & Polyamines: A Novel Metabolic Feedback Loop."

    More information
    שעה
    10:00 - 10:30
    מיקום
    בניין וולפסון למחקר ביולוגי
    מרצהZiv Zwighaft, WIS-Department of Biological Chemistry
    מארגן
    המחלקה למדעים ביומולקולריים
    צרו קשר
    הרצאה
  • Date:27שלישינובמבר 2012

    "The molecular basis of phosphate discrimination in arsenate rich environments”

    More information
    שעה
    10:30 - 11:00
    מיקום
    בניין וולפסון למחקר ביולוגי
    מרצהMikael Elias
    WIS-Department of Biological Chemistry
    מארגן
    המחלקה למדעים ביומולקולריים
    צרו קשר
    הרצאה
  • Date:27שלישינובמבר 2012

    Adaptive Control of a Nonlinear Output, with an Application to Wind-Turbine Control

    More information
    שעה
    11:00 - 11:00
    מיקום
    בניין יעקב זיסקינד
    מרצהYoav Sharon
    MIT
    מארגן
    הפקולטה למתמטיקה ומדעי המחשב
    צרו קשר
    הרצאה
  • Date:27שלישינובמבר 2012

    "Organic-based Magnets: New Chemistry and New Materials for this Millennium"

    More information
    שעה
    11:00 - 11:00
    כותרת
    Department Of Organic Chemistry - Departmental Seminar
    מיקום
    בניין הלן ומילטון קימלמן
    מרצהProf. Joel S. Miller
    Department of Chemistry, University of Utah, Salt Lake City
    מארגן
    המחלקה לכימיה מולקולרית ולמדע חומרים
    צרו קשר
    תקצירShow 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.

    הרצאה
  • Date:27שלישינובמבר 2012

    "Mechanisms, rates and specificities in grass genome instability"

    More information
    שעה
    11:15 - 11:15
    מיקום
    בניין ארתור ורושל בלפר למחקר ביורפואי
    מרצהProf. Jeffrey (Jeff) Bennetzen
    Davison Life Sciences Complex, Department of Genetics, University of Georgia, Athens – GA, USA
    מארגן
    המחלקה למדעי הצמח והסביבה
    צרו קשר
    הרצאה
  • Date:27שלישינובמבר 2012

    What can parasitoid wasps teach us about decision making in the brain of insects?

    More information
    שעה
    12:30 - 12:30
    מיקום
    אולם הרצאות ע"ש גרהרד שמידט
    מרצהProf. Frederic Libersat
    Life Sciences Dept, Ben Gurion University of the Negev, Beer Sheva
    מארגן
    המחלקה למדעי המוח
    צרו קשר
    תקצירShow 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.
    הרצאה
  • Date:27שלישינובמבר 2012

    "The tails of p63 or 2 inactive 4 destruction"

    More information
    שעה
    14:00 - 15:00
    מיקום
    אולם הרצאות ע"ש גרהרד שמידט
    מרצהProf. Volker Doetsch
    Institute of Biophysical Chemistry, Goethe University Frankfurt/Germany
    מארגן
    המחלקה לביולוגיה מבנית וכימית
    צרו קשר
    הרצאה
  • Date:27שלישינובמבר 2012

    "ממזרח למערב"

    More information
    שעה
    20:30 - 20:30
    כותרת
    טילדה רג'ואן
    מיקום
    אודיטוריום מיכאל סלע
    צרו קשר
    אירועי תרבות
  • Date:28רביעינובמבר 2012

    On representations of affine Lie superalgebras

    More information
    שעה
    11:00 - 11:00
    מיקום
    בניין יעקב זיסקינד
    מרצהProf. Maria Gorelik
    מארגן
    הפקולטה למתמטיקה ומדעי המחשב
    צרו קשר
    הרצאה
  • Date:28רביעינובמבר 2012

    Spotlight on Science

    More information
    שעה
    12:00 - 13:30
    כותרת
    Harnessing DNA Repair for Lung Cancer Prevention and Early Detection
    מיקום
    אולם הרצאות ע"ש גרהרד שמידט
    מרצהDr. Tamar Paz-Elizur
    Department of Biological Chemistry
    צרו קשר
    הרצאה
  • Date:28רביעינובמבר 2012

    שלישיית יובל

    More information
    שעה
    12:30 - 13:30
    כותרת
    מינחה מוזיקלית
    מיקום
    אודיטוריום מיכאל סלע
    צרו קשר
    אירועי תרבות
  • Date:29חמישינובמבר 201202שבתפברואר 2013

    יונה ונער

    More information
    שעה
    כל היום
    כותרת
    עיבוד ראשון לרומן רב המכר מאת מאיר שלו.
    מיקום
    אודיטוריום מיכאל סלע
    צרו קשר
    אירועי תרבות
  • Date:29חמישינובמבר 2012

    Biomedical super-resolved sensing

    More information
    שעה
    12:00 - 12:00
    מיקום
    בניין יעקב זיסקינד
    מרצהZeev Zalevsky
    Bar-Ilan University
    מארגן
    הפקולטה למתמטיקה ומדעי המחשב
    צרו קשר
    הרצאה
  • Date:29חמישינובמבר 2012

    Life Science Lecture

    More information
    שעה
    15:00 - 16:00
    כותרת
    From letters to function: Cracking the code of gene regulation
    מיקום
    אולם ע"ש דולפי ולולה אבנר
    מרצהProf. Eran Segal
    Department of Computer Science and Applied Mathematics
    צרו קשר
    הרצאה
  • Date:30שישינובמבר 2012

    "חתונה יהודית"

    More information
    שעה
    11:00 - 13:00
    כותרת
    דר' רוחמה אלבג
    מיקום
    אולם ע"ש דולפי ולולה אבנר
    צרו קשר
    אירועי תרבות
  • Date:02ראשוןדצמבר 201206חמישידצמבר 2012

    FUNTRAP12- ISF Conference on Fundamental Interactions with Atom and Ion Traps

    More information
    שעה
    כל היום
    מיקום
    בניין הפיזיקה ע"ש עדנה וק.ב. וייסמן
    יושב ראש
    Michael Hass
    דף בית
    צרו קשר
    כנסים

Pages