16,746 research outputs found
Statement of William B. Gould IV Before the Commission on the Future of Worker-Management Relations
Testimony_Gould_092994.pdf: 255 downloads, before Oct. 1, 2020
Rocket exhaust ground cloud/atmospheric interactions
An attempt to identify and minimize the uncertainties and potential inaccuracies of the NASA Multilayer Diffusion Model (MDM) is performed using data from selected Titan 3 launches. The study is based on detailed parametric calculations using the MDM code and a comparative study of several other diffusion models, the NASA measurements, and the MDM. The results are discussed and evaluated. In addition, the physical/chemical processes taking place during the rocket cloud rise are analyzed. The exhaust properties and the deluge water effects are evaluated. A time-dependent model for two aerosol coagulations is developed and documented. Calculations using this model for dry deposition during cloud rise are made. A simple model for calculating physical properties such as temperature and air mass entrainment during cloud rise is also developed and incorporated with the aerosol model
Twisted Quantum Affine Superalgebra and New Invariant R-matrices
The minimal irreducible representations of , i.e. those
irreducible representations that are also irreducible under are
investigated and shown to be affinizable to give irreducible representations of
the twisted quantum affine superalgebra . The
invariant R-matrices corresponding to the tensor product of any
two minimal representations are constructed, thus extending our twisted tensor
product graph method to the supersymmetric case. These give new solutions to
the spectral-dependent graded Yang-Baxter equation arising from
, which exhibit novel features not previously seen in the
untwisted or non-super cases.Comment: 19 pages, Latex fil
The Functional Significance of Black-Pigmented Leaves: Photosynthesis, Photoprotection and Productivity in Ophiopogon planiscapus ‘Nigrescens’
Black pigmented leaves are common among horticultural cultivars, yet are extremely rare across natural plant populations. We hypothesised that black pigmentation would disadvantage a plant by reducing photosynthesis and therefore shoot productivity, but that this trait might also confer protective benefits by shielding chloroplasts against photo-oxidative stress. CO2 assimilation, chlorophyll a fluorescence, shoot biomass, and pigment concentrations were compared for near isogenic green- and black-leafed Ophiopogon planiscapus ‘Nigrescens’. The black leaves had lower maximum CO2 assimilation rates, higher light saturation points and higher quantum efficiencies of photosystem II (PSII) than green leaves. Under saturating light, PSII photochemistry was inactivated less and recovered more completely in the black leaves. In full sunlight, green plants branched more abundantly and accumulated shoot biomass quicker than the black plants; in the shade, productivities of the two morphs were comparable. The data indicate a light-screening, photoprotective role of foliar anthocyanins. However, limitations to photosynthetic carbon assimilation are relatively small, insufficient to explain the natural scarcity of black-leafed plants
Quantum Hall effect in narrow graphene ribbons
The edge states in the integer quantum Hall effect are known to be
significantly affected by electrostatic interactions leading to the formation
of compressible and incompressible strips at the boundaries of Hall bars. We
show here, in a combined experimental and theoretical analysis, that this does
not hold for the quantum Hall effect in narrow graphene ribbons. In our
graphene Hall bar, which is only 60 nm wide, we observe the quantum Hall effect
up to Landau level index k=2 and show within a zero free-parameter model that
the spatial extent of the compressible and incompressible strips is of a
similar magnitude as the magnetic length. We conclude that in narrow graphene
ribbons the single-particle picture is a more appropriate description of the
quantum Hall effect and that electrostatic effects are of minor importance.Comment: RevTex, 5 pages, 4 figures (matches published version
Antitrust and Higher Education: What Hath Justice Wrought?
The MIT case signals a new era for higher education. Colleges and universities must now conduct their activities in compliance with the antitrust laws. The recent Amendments to the Higher Education Act offer a limited antitrust immunity for certain collective financial aid activities, but all other aspects of higher education are now subject to antitrust scrutiny. As a likely result, prudent college and university officials will adopt antitrust compliance programs to protect against inadvertent antitrust violations that could expose their institutions to private treble damage litigation, or worse
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