7,836 research outputs found
âWe kind of try to merge our own experience with the objectivity of the criteriaâ: The role of connoisseurship and tacit practice in undergraduate fine art assessment
This article explores connoisseurship in the context of fine art undergraduate assessment practice. I interviewed twelve fine art lecturers in order to explore and unpack
the concept of connoisseurship in relation to subjectivity, objectivity and tacit practice.
Building on the work of Bourdieu (1973, 1977, 1986) and Shay (2003, 2005), both of whom problematize the view that subjectivity and objectivity are binary opposites, my
research illustrates the ways that connoisseurship is underpinned by informed professional judgements located in communities of practice. Within this particular conception
of connoisseurship, the lecturersâ expertise is co-constituted in communities of assessors through participation and engagement. Standards reside in communities of practice
Additional Soft Jets in Production at the Tevatron \pp Collider
A large fraction of top quark events in \pp collisions at 1.8\ \TeV will
contain additional soft hadronic jets from gluon bremsstrahlung off the quarks
and gluons in the hard processes \qq, gg \to \tt \to \bb \ww. These extra
jets can cause complications when attempting to reconstruct from the
invariant mass of combinations of final-state quarks and leptons. We show how
such soft radiation cannot be unambiguously associated with either
initial-state radiation or or with final-state radiation off the quarks.
The top quarks can radiate too, and in fact the pattern of radiation has a very
rich structure, which depends on the orientation of the final-state particles
with respect to each other and with respect to the beam. We calculate the full
radiation pattern of soft jets in the soft gluon approximation and compare with
several approximate forms which are characteristic of parton shower Monte
Carlos. The implications for top mass measurements are discussed.Comment: plain LaTeX, 13 pages plus 9 figures included as a separate uuencoded
file (or avail. from authors); DTP/94/60, UR-136
Effect of surface tension on the growth mode of highly strained InGaAs on GaAs(100)
We have investigated the molecular beam epitaxy growth of highly strained InGaAs on GaAs(100) as a function of the anion to cation flux ratio. Using reflection high energy electron diffraction the evolution of the film morphology is monitored and the surface lattice constant is measured. It is found that the cation to anion flux ratio dramatically affects the growth mode. Under arsenicârich conditions, growth is characterized by a twoâdimensional (2D) to threeâdimensional (3D) morphological transformation. However, for cationâstabilized conditions, 3D islanding is completely suppressed, and 2D planar growth is observed. We associate these differences in the growth mode with corresponding changes in the surface tension of the overlayer. A high surface tension stabilizes 2D growth. An analysis which relates surface tension to a critical thickness for the onset of coherent island formation supports this view.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70295/2/APPLAB-62-1-46-1.pd
The Interrelationships of Bark Beetles and Blue-Staining Fungi in Felled Norway Pine Timber
A study of two species of bark beetle (lps pini Say and I. grandicollis Eichh.) and the fungi associated with them has been made as the first part of a general investigation of the interrelations of insects and fungi in the deterioration of felled logs of Norway pine
Periodic magnetorotational dynamo action as a prototype of nonlinear magnetic field generation in shear flows
The nature of dynamo action in shear flows prone to magnetohydrodynamic
instabilities is investigated using the magnetorotational dynamo in Keplerian
shear flow as a prototype problem. Using direct numerical simulations and
Newton's method, we compute an exact time-periodic magnetorotational dynamo
solution to the three-dimensional dissipative incompressible
magnetohydrodynamic equations with rotation and shear. We discuss the physical
mechanism behind the cycle and show that it results from a combination of
linear and nonlinear interactions between a large-scale axisymmetric toroidal
magnetic field and non-axisymmetric perturbations amplified by the
magnetorotational instability. We demonstrate that this large scale dynamo
mechanism is overall intrinsically nonlinear and not reducible to the standard
mean-field dynamo formalism. Our results therefore provide clear evidence for a
generic nonlinear generation mechanism of time-dependent coherent large-scale
magnetic fields in shear flows and call for new theoretical dynamo models.
These findings may offer important clues to understand the transitional and
statistical properties of subcritical magnetorotational turbulence.Comment: 10 pages, 6 figures, accepted for publication in Physical Review
A combined molecularâbeam epitaxy and scanning tunneling microscopy system
A combined molecularâbeam epitaxy and scanning tunneling microscopy system has been constructed. The design has been optimized for the study of IIIâV semiconductors with the goal of examining the surface with both in situ scanning tunneling microscopy (STM) and reflection highâenergy electron diffraction (RHEED). Using this system, it is possible to quench the growth and produce realâspace images of the surface as it appeared during deposition. Measurements obtained with both RHEED and STM are presented.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70399/2/RSINAK-62-6-1400-1.pd
Probing Electroweak Top Quark Couplings at Hadron Colliders
We consider QCD t\bar{t}\gamma and t\bar{t}Z production at hadron colliders
as a tool to measure the tt\gamma and ttZ couplings. At the Tevatron it may be
possible to perform a first, albeit not very precise, test of the tt\gamma
vector and axial vector couplings in t\bar{t}\gamma production, provided that
more than 5 fb^{-1} of integrated luminosity are accumulated. The t\bar{t}Z
cross section at the Tevatron is too small to be observable. At the CERN Large
Hadron Collider (LHC) it will be possible to probe the tt\gamma couplings at
the few percent level, which approaches the precision which one hopes to
achieve with a next-generation e^+e^- linear collider. The LHC's capability of
associated QCD t\bar{t}V (V=\gamma, Z) production has the added advantage that
the tt\gamma and ttZ couplings are not entangled. For an integrated luminosity
of 300 fb^{-1}, the ttZ vector (axial vector) coupling can be determined with
an uncertainty of 45-85% (15-20%), whereas the dimension-five dipole form
factors can be measured with a precision of 50-55%. The achievable limits
improve typically by a factor of 2-3 for the luminosity-upgraded (3 ab^{-1})
LHC.Comment: Revtex3, 30 pages, 9 Figures, 6 Table
CCDâbased reflection highâenergy electron diffraction detection and analysis system
A CCDâbased, computer controlled RHEED detection and analysis system that utilizes an onâchip integration technique and onâboard data manipulation is described. The system is capable of in situ timeâresolved measurements of specular and integralâorder intensity oscillations, their phase differences, streak linewidths, and epitaxial layer lattice constants. The digital RHEED techniques are described in the context of Co/Au bilayer, GaAs/GaAs, and InxGa1âxAs/GaAs MBE growth. The system is compared to other RHEED detection devices.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70680/2/RSINAK-62-5-1263-1.pd
Gluon Radiation in Production and Decay at the LHC
Understanding the pattern of gluon radiation in production and
decay processes is important for making an accurate determination of the top
mass from the momenta of its decay products. The larger energy of the LHC
collider boosts the top cross section by a factor of 100 compared to that at
the Tevatron, but it also increases the amount of additional gluon radiation.
We calculate the cross section for gluon radiation in top production and decay
at the LHC. The distributions of this radiation are presented and the exact
matrix-element results are compared with results from the HERWIG parton-shower
Monte Carlo.Comment: 16 pages including 7 figures, plain LaTeX; minor corrections to text;
results unchange
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