386 research outputs found
Relativistic quantum measurement
Does the measurement of a quantum system necessarily break Lorentz
invariance? We present a simple model of a detector that measures the spacetime
localization of a relativistic particle in a Lorentz invariant manner. The
detector does not select a preferred Lorentz frame as a Newton-Wigner
measurement would do. The result indicates that there exists a Lorentz
invariant notion of quantum measurement and sheds light on the issue of the
localization of a relativistic particle. The framework considered is that of
single-particle mechanics as opposed to field theory. The result may be taken
as support for the interpretation postulate of the spacetime-states formulation
of single-particle quantum theory.Comment: 9 pages, no figures: Revision: references adde
Transparency in higher education:The emergence of a new perspective on higher education governance
Reliable information and transparency on the benefits that higher education institutions offer their students, funders and communities is key for their legitimacy, their funding and their competitiveness. Worldwide, relationships between governmental authorities and higher education institutions are changing, particularly because of the increased demands for transparency about outcomes and impacts of higher education. In our contribution, we discuss three higher education ‘transparency tools’: accreditation, rankings and—briefly—performance contracts. We present some recent developments regarding these tools in the broader context of governance and policy making and analyse how they aim to address the growing need for more transparency. The transparency tools are part of a recently emerging governance paradigm in higher education, networked governance; a paradigm that explicitly acknowledges the diverse information needs of a wide variety of higher education stakeholder groups
Nutritional effects of beef connective tissue characteristics and eating qualities
We compared taste panel and connective tissue characteristics of beef fed a high energy diet with beef fed grass. The high energy diet produced higher USDA quality and yield grades, more rapid weight gain, and increased connective tissue collagen synthesis arid breakdown. But, it did not consistently improve taste panel and shear characteristics over grass-feeding
Observational Validation of The Compensating Mass Flux Through The Shell Around Cumulus Clouds
The existence of a subsiding shell around cumulus clouds has been observed before in several aircraft measurement campaigns. Recent results from large-eddy simulations (LES) showed that the downward mass flux through the shell compensates for a significant fraction of the upward mass flux through the cloud. In this study, aeroplane measurements from the Rain In Cumulus over the Ocean (RICO) field campaign are used to verify the existence of this compensating mass flux. Just as in the LES results, the in-shell downward mass flux is found to be significant. However, a few differences were found in comparison with the LES results; most of them were explained by taking into account the difference between the two-dimensional slabs in LES and the one-dimensional lines from aeroplane observations
Mapping and Critical Synthesis of Current State-of-the-Art on Community Engagement in Higher Education
Fermions, T-duality and effective actions for D-branes in bosonic backgrounds
We find the effective action for any D-brane in a general bosonic background
of supergravity. The results are explicit in component fields up to second
order in the fermions and are obtained in a covariant manner. No interaction
terms between fermions and the field , characteristic of the bosonic
actions, are considered. These are reserved for future work. In order to obtain
the actions, we reduce directly from the M2-brane world-volume action to the
D2-brane world-volume action. Then, by means of T-duality, we obtain the other
Dp-brane actions. The resulting Dp-brane actions can be written in a single
compact and elegant expression.Comment: 22 pages, latex, version published by JHEP plus typos corrected in
eq.(44) and eq.(47
Magnetic fields in cosmic particle acceleration sources
We review here some magnetic phenomena in astrophysical particle accelerators
associated with collisionless shocks in supernova remnants, radio galaxies and
clusters of galaxies. A specific feature is that the accelerated particles can
play an important role in magnetic field evolution in the objects. We discuss a
number of CR-driven, magnetic field amplification processes that are likely to
operate when diffusive shock acceleration (DSA) becomes efficient and
nonlinear. The turbulent magnetic fields produced by these processes determine
the maximum energies of accelerated particles and result in specific features
in the observed photon radiation of the sources. Equally important, magnetic
field amplification by the CR currents and pressure anisotropies may affect the
shocked gas temperatures and compression, both in the shock precursor and in
the downstream flow, if the shock is an efficient CR accelerator. Strong
fluctuations of the magnetic field on scales above the radiation formation
length in the shock vicinity result in intermittent structures observable in
synchrotron emission images. Resonant and non-resonant CR streaming
instabilities in the shock precursor can generate mesoscale magnetic fields
with scale-sizes comparable to supernova remnants and even superbubbles. This
opens the possibility that magnetic fields in the earliest galaxies were
produced by the first generation Population III supernova remnants and by
clustered supernovae in star forming regions.Comment: 30 pages, Space Science Review
Collisions with Black Holes and Deconfined Plasmas
We use AdS/CFT to investigate i) high energy collisions with balls of
deconfined plasma surrounded by a confining phase and ii) the rapid localized
heating of a deconfined plasma. Both of these processes are dual to collisions
with black holes, where they result in the nucleation of a new "arm" of the
horizon reaching out in the direction of the incident object. We study the
resulting non-equilibrium dynamics in a universal limit of the gravitational
physics which may indicate universal behavior of deconfined plasmas at large
N_c. Process (i) produces "virtual" arms of the plasma ball, while process (ii)
can nucleate surprisingly large bubbles of a higher temperature phase.Comment: 25 pages, 9 figure
The New Political History
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66569/2/10.1177_000276427702100204.pd
Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector
A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
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