1,415 research outputs found
Using their Own Stories: A Culturally Relevant Response to Intervention
Driven by sociocultural theories, First Author, Maggie conducted a critical action research study of her attempts to enact culturally relevant practices in a Response to Intervention (RtI) reading group. A grounded theory approach informed the analysis of her data. In this paper, we theorize three themes that were generated from the data analysis. We assert that in order to prevent RtI from becoming another unsuccessful, de-contextualized, large-scale effort, teachers and students would benefit from a culturally relevant response to interventionâa commitment to locate the contextual contingencies in which RtI is being implemented; to pay attention to what happens in the âdown timeâ outside of the scripted parts of RtI lessons; and to make explicit efforts to use childrenâs own stories as the RtI texts
Spin exchange interaction with tunable range between graphene quantum dots
We study the spin exchange between two electrons localized in separate
quantum dots in graphene. The electronic states in the conduction band are
coupled indirectly by tunneling to a common continuum of delocalized states in
the valence band. As a model, we use a two-impurity Anderson Hamiltonian which
we subsequently transform into an effective spin Hamiltonian by way of a
two-stage Schrieffer-Wolff transformation. We then compare our result to that
from a Coqblin-Schrieffer approach as well as to fourth order perturbation
theory.Comment: 8 pages, 3 figure
Excitated state properties of 20-chloro-chlorophyll a
The excited-state and lasing properties of 20-chloro-chlorophyll a in ether solution were compared to those of chlorophyll a. Desactivation parameters and cross-sections were obtained from non-linear absorption spectroscopy in combination with a physico-mathematical methods package. The Cl substituent at C-20 (1) increases both intersystem crossing and internal conversion, (2) produces a blue-shift of the S1 absorption spectrum, and (3) leads to pronounced photochemistry
Simple Models for Turbulent Self-Regulation in Galaxy Disks
We propose that turbulent heating, wave pressure and gas exchanges between
different regions of disks play a dominant role in determining the preferred,
quasi-equilibrium, self-similar states of gas disks on large-scales. We present
simple families of analytic, thermohydrodynamic models for these global states,
which include terms for turbulent pressure and Reynolds stresses. Star
formation rates, phase balances, and hydrodynamic forces are all tightly
coupled and balanced. The models have stratified radial flows, with the cold
gas slowly flowing inward in the midplane of the disk, and with the warm/hot
phases that surround the midplane flowing outward.
The models suggest a number of results that are in accord with observation,
as well as some novel predictions, including the following. 1) The large-scale
gas density and thermal phase distributions in galaxy disks can be explained as
the result of turbulent heating and spatial couplings. 2) The turbulent
pressures and stresses that drive radial outflows in the warm gas also allow a
reduced circular velocity there. This effect was observed by Swaters, Sancisi
and van der Hulst in NGC 891, a particularly turbulent edge-on disk. The models
predict that the effect should be universal in such disks. 3) They suggest that
a star formation rate like the phenomenological Schmidt Law is the natural
result of global thermohydrodynamical balance, and may not obtain in disks far
from equilibrium. (Abridged)Comment: 37 pages, 1 gif figure, accepted for publication in the Astrophysical
Journa
The Minimum Stellar Mass in Early Galaxies
The conditions for the fragmentation of the baryonic component during merging
of dark matter halos in the early Universe are studied. We assume that the
baryonic component undergoes a shock compression. The characteristic masses of
protostellar molecular clouds and the minimum masses of protostars formed in
these clouds decrease with increasing halo mass. This may indicate that the
initial stellar mass function in more massive galaxies was shifted towards
lower masses during the initial stages of their formation. This would result in
an increase of the number of stars per unit halo mass, i.e., the efficiency of
star formation.Comment: 18 pages, 7 figure
Elliptic flow in Au+Au collisions at sqrt sNN = 130 GeV
Elliptic flow from nuclear collisions is a hadronic observable sensitive to the early stages of system evolution. We report first results on elliptic flow of charged particles at midrapidity in Au+Au collisions at sqrt[sNN] = 130 GeV using the STAR Time Projection Chamber at the Relativistic Heavy Ion Collider. The elliptic flow signal, v2, averaged over transverse momentum, reaches values of about 6% for relatively peripheral collisions and decreases for the more central collisions. This can be interpreted as the observation of a higher degree of thermalization than at lower collision energies. Pseudorapidity and transverse momentum dependence of elliptic flow are also presented.alle Autoren: K. H. Ackermann19, N. Adams28, C. Adler12, Z. Ahammed27, S. Ahmad28, C. Allgower13, J. Amsbaugh34, M. Anderson6, E. Anderssen17, H. Arnesen3, L. Arnold14, G. S. Averichev10, A. Baldwin16, J. Balewski13, O. Barannikova10,27, L. S. Barnby16, J. Baudot14, M. Beddo1, S. Bekele24, V. V. Belaga10, R. Bellwied35, S. Bennett35, J. Bercovitz17, J. Berger12, W. Betts24, H. Bichsel34, F. Bieser17, L. C. Bland13, M. Bloomer17, C. O. Blyth4, J. Boehm17, B. E. Bonner28, D. Bonnet14, R. Bossingham17, M. Botlo3, A. Boucham30, N. Bouillo30, S. Bouvier30, K. Bradley17, F. P. Brady6, E. S. Braithwaite2, W. Braithwaite2, A. Brandin21, R. L. Brown3, G. Brugalette34, C. Byrd2, H. Caines24, M. CalderĂłn de la Barca SĂĄnchez36, A. Cardenas27, L. Carr34, J. Carroll17, J. Castillo30, B. Caylor17, D. Cebra6, S. Chatopadhyay35, M. L. Chen3, W. Chen3, Y. Chen7, S. P. Chernenko10, M. Cherney9, A. Chikanian36, B. Choi31, J. Chrin9, W. Christie3, J. P. Coffin14, L. Conin30, C. Consiglio3, T. M. Cormier35, J. G. Cramer34, H. J. Crawford5, V. I. Danilov10, D. Dayton3, M. DeMello28, W. S. Deng16, A. A. Derevschikov26, M. Dialinas30, H. Diaz3, P. A. DeYoung8, L. Didenko3, D. Dimassimo3, J. Dioguardi3, W. Dominik32, C. Drancourt30, J. E. Draper6, V. B. Dunin10, J. C. Dunlop36, V. Eckardt19, W. R. Edwards17, L. G. Efimov10, T. Eggert19, V. Emelianov21, J. Engelage5, G. Eppley28, B. Erazmus30, A. Etkin3, P. Fachini29, C. Feliciano3, D. Ferenc6, M. I. Ferguson7, H. Fessler19, E. Finch36, V. Fine3, Y. Fisyak3, D. Flierl12, I. Flores5, K. J. Foley3, D. Fritz17, N. Gagunashvili10, J. Gans36, M. Gazdzicki12, M. Germain14, F. Geurts28, V. Ghazikhanian7, C. Gojak14, J. Grabski33, O. Grachov35, M. Grau3, D. Greiner17, L. Greiner5, V. Grigoriev21, D. Grosnick1, J. Gross9, G. Guilloux30, E. Gushin21, J. Hall35, T. J. Hallman3, D. Hardtke17, G. Harper34, J. W. Harris36, P. He5, M. Heffner6, S. Heppelmann25, T. Herston27, D. Hill1, B. Hippolyte14, A. Hirsch27, E. Hjort27, G. W. Hoffmann31, M. Horsley36, M. Howe34, H. Z. Huang7, T. J. Humanic24, H. HĂŒmmler19, W. Hunt13, J. Hunter17, G. J. Igo7, A. Ishihara31, Yu. I. Ivanshin11, P. Jacobs17, W. W. Jacobs13, S. Jacobson17, R. Jared17, P. Jensen31, I. Johnson17, P. G. Jones4, E. Judd5, M. Kaneta17, M. Kaplan8, D. Keane16, V. P. Kenney23*, A. Khodinov21, J. Klay6, S. R. Klein17, A. Klyachko13, G. Koehler17, A. S. Konstantinov26, V. Kormilitsyne7,26, L. Kotchenda21, I. Kotov24, A. D. Kovalenko10, M. Kramer22, P. Kravtsov21, K. Krueger1, T. Krupien3, P. Kuczewski3, C. Kuhn14, G. J. Kunde36, C. L. Kunz8, R. Kh. Kutuev11, A. A. Kuznetsov10, L. Lakehal-Ayat30, J. Lamas-Valverde28, M. A. C. Lamont4, J. M. Landgraf3, S. Lange12, C. P. Lansdell31, B. Lasiuk36, F. Laue24, A. Lebedev3, T. LeCompte1, W. J. Leonhardt3, V. M. Leontiev26, P. Leszczynski33, M. J. LeVine3, Q. Li35, Q. Li17, Z. Li3, C.-J. Liaw3, J. Lin9, S. J. Lindenbaum22, V. Lindenstruth5, P. J. Lindstrom5, M. A. Lisa24, H. Liu16, T. Ljubicic3, W. J. Llope28, G. LoCurto19, H. Long7, R. S. Longacre3, M. Lopez-Noriega24, D. Lopiano1, W. A. Love3, J. R. Lutz14, D. Lynn3, L. Madansky15§, R. Maier19, R. Majka36, A. Maliszewski33, S. Margetis16, K. Marks17, R. Marstaller19, L. Martin30, J. Marx17, H. S. Matis17, Yu. A. Matulenko26, E. A. Matyushevski10, C. McParland17, T. S. McShane9, J. Meier9, Yu. Melnick26, A. Meschanin26, P. Middlekamp3, N. Mikhalin7,26, B. Miller3, Z. Milosevich8, N. G. Minaev26, B. Minor17, J. Mitchell15, E. Mogavero3, V. A. Moiseenko11, D. Moltz17, C. F. Moore31, V. Morozov17, R. Morse17, M. M. de Moura29, M. G. Munhoz29, G. S. Mutchler28, J. M. Nelson4, P. Nevski3, T. Ngo7, M. Nguyen3, T. Nguyen3, V. A. Nikitin11, L. V. Nogach26, T. Noggle17, B. Norman16, S. B. Nurushev26, T. Nussbaum28, J. Nystrand17, G. Odyniec17, A. Ogawa25, C. A. Ogilvie18, K. Olchanski3, M. Oldenburg19, D. Olson17, G. A. Ososkov10, G. Ott31, D. Padrazo3, G. Paic24, S. U. Pandey35, Y. Panebratsev10, S. Y. Panitkin16, A. I. Pavlinov26, T. Pawlak33, M. Pentia10, V. Perevotchikov3, W. Peryt33, V. A Petrov11, W. Pinganaud30, S. Pirogov7, E. Platner28, J. Pluta33, I. Polk3, N. Porile27, J. Porter3, A. M. Poskanzer17, E. Potrebenikova10, D. Prindle34, C. Pruneau35, J. Puskar-Pasewicz13, G. Rai17, J. Rasson17, O. Ravel30, R. L. Ray31, S. V. Razin10,13, D. Reichhold9, J. Reid34, R. E. Renfordt12, F. Retiere30, A. Ridiger21, J. Riso35, H. G. Ritter17, J. B. Roberts28, D. Roehrich12, O. V. Rogachevski10, J. L. Romero6, C. Roy30, D. Russ8, V. Rykov35, I. Sakrejda17, R. Sanchez7, Z. Sandler7, J. Sandweiss36, P. Sappenfield28, A. C. Saulys3, I. Savin11, J. Schambach31, R. P. Scharenberg27, J. Scheblien3, R. Scheetz3, R. Schlueter17, N. Schmitz19, L. S. Schroeder17, M. Schulz3,19, A. SchĂŒttauf19, J. Sedlmeir3, J. Seger9, D. Seliverstov21, J. Seyboth19, P. Seyboth19, R. Seymour34, E. I. Shakaliev10, K. E. Shestermanov26, Y. Shi7, S. S. Shimanskii10, D. Shuman17, V. S. Shvetcov11, G. Skoro10, N. Smirnov36, L. P. Smykov10, R. Snellings17, K. Solberg13, J. Sowinski13, H. M. Spinka1, B. Srivastava27, E. J. Stephenson13, R. Stock12, A. Stolpovsky35, N. Stone3, R. Stone17, M. Strikhanov21, B. Stringfellow27, H. Stroebele12, C. Struck12, A. A. P. Suaide29, E. Sugarbaker24, C. Suire14, T. J. M. Symons17, J. Takahashi29, A. H. Tang16, A. Tarchini14, J. Tarzian17, J. H. Thomas17, V. Tikhomirov21, A. Szanto de Toledo29, S. Tonse17, T. Trainor34, S. Trentalange7, M. Tokarev10, M. B. Tonjes20, V. Trofimov21, O. Tsai7, K. Turner3, T. Ullrich36, D. G. Underwood1, I. Vakula7, G. Van Buren3, A. M. VanderMolen20, A. Vanyashin17, I. M. Vasilevski11, A. N. Vasiliev26, S. E. Vigdor13, G. Visser5, S. A. Voloshin35, C. Vu17, F. Wang27, H. Ward31, D. Weerasundara34, R. Weidenbach17, R. Wells17, R. Wells24, T. Wenaus3, G. D. Westfall20, J. P. Whitfield8, C. Whitten, Jr.7, H. Wieman17, R. Willson24, K. Wilson35, J. Wirth17, J. Wisdom7, S. W. Wissink13, R. Witt16, J. Wolf17, L. Wood6, N. Xu17, Z. Xu36, A. E. Yakutin26, E. Yamamoto7, J. Yang7, P. Yepes28, A. Yokosawa1, V. I. Yurevich10, Y. V. Zanevski10, J. Zhang17, W. M. Zhang16, J. Zhu34, D. Zimmerman17, R. Zoulkarneev11, and A. N. Zubare
Extra-nuclear starbursts: Young luminous hinge clumps in interacting galaxies
Hinge clumps are luminous knots of star formation near the base of tidal features in some interacting galaxies. We use archival Hubble Space Telescope (HST) UV/optical/IR images and Chandra X-ray maps along with Galaxy Evolution Explorer UV, Spitzer IR, and ground-based optical/near-IR images to investigate the star forming properties in a sample of 12 hinge clumps in five interacting galaxies. The most extreme of these hinge clumps have star formation rates of 1-9 M â yrâ1, comparable to or larger than the "overlap" region of intense star formation between the two disks of the colliding galaxy system the Antennae. In the HST images, we have found remarkably large and luminous sources at the centers of these hinge clumps. These objects are much larger and more luminous than typical "super star clusters" in interacting galaxies, and are sometimes embedded in a linear ridge of fainter star clusters, consistent with star formation along a narrow caustic. These central sources have FWHM diameters of ~70 pc, compared to ~3 pc in "ordinary" super star clusters. Their absolute I magnitudes range from MI ~ â 12.2 to â16.5; thus, if they are individual star clusters they would lie near the top of the "super star cluster" luminosity function of star clusters. These sources may not be individual star clusters, but instead may be tightly packed groups of clusters that are blended together in the HST images.Comparison to population synthesis modeling indicates that the hinge clumps contain a range of stellar ages. This is consistent with expectations based on models of galaxy interactions, which suggest that star formation may be prolonged in these regions.In the Chandra images, we have found strong X-ray emission from several of these hinge clumps. In most cases, this emission is well-resolved with Chandra and has a thermal X-ray spectrum, thus it is likely due to hot gas associated with the star formation. The ratio of the extinction-corrected diffuse X-ray luminosity to the mechanical energy rate (the X-ray production efficiency) for the hinge clumps is similar to that in the Antennae galaxies, but higher than those for regions in the normal spiral galaxy NGC 2403. Two of the hinge clumps have point-like X-ray emission much brighter than expected for hot gas; these sources are likely "ultra-luminous X-ray sources" due to accretion disks around black holes. The most extreme of these sources, in Arp 240, has a hard X-ray spectrum and an absorbed X-ray luminosity of ~2 Ă 1041 erg sâ1; this is above the luminosity expected by single high mass X-ray binaries (HMXBs), thus it may be either a collection of HMXBs or an intermediate mass black hole (â„80 M â)
Flower-enhanced expression of a nuclear-encoded mitochondrial respiratory protein is associated with changes in mitochondrion number.
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