44,936 research outputs found
Evidence of endothelial dysfunction in the development of Alzheimer's disease : Is Alzheimer's a vascular disorder?
Acknowledgements Dr Soiza is funded by an NRS Career Research Fellowship. The authors are grateful to Alzheimer’s Research UK for providing funding.Peer reviewedPublisher PD
Apparatus for handling micron size range particulate material
An apparatus for handling, transporting, or size classifying comminuted material was described in detail. Electrostatic acceleration techniques for classifying particles as to size in the particle range from 0.1 to about 100 microns diameter were employed
Merger Simulation: A Simplified Approach with New Applications
Merger simulation is growing in importance as a tool to evaluate the unilateral competitive effects of mergers. This paper offers a relatively non-technical description of the principles of merger simulation. In addition, it introduces PCAIDS, a new and highly flexible "calibrated-demand" merger simulation methodology that is based on a simplified version of AIDS. PCAIDS can be implemented using market shares and two price elasticities; scanner or transaction-level data are not required. The paper offers some applications of merger simulation with PCAIDS that include comparisons with other simulation models. It also shows how PCAIDS can be applied to the analysis of efficiencies, divestiture, and product repositioning/entry. Finally, the paper offers an analysis of the Merger Guidelines safeharbors. A detailed mathematical appendix is included.
Merger Simulation with Brand-Level Margin: Extending PCAIDS with Nests
We present a method to calibrate empirically the demand parameters in a merger simulation model by using brand-level profit margin data. While the approach can be generalized, we develop these ideas within a particular framework the PCAIDS (proportionality- calibrated AIDS) model. We show that the brand-level margins effectively define product "nests" (products that are especially close substitutes) and substantially increase the flexibility of PCAIDS for modeling critical own- and cross-price elasticities. The model is particularly valuable for transactions at the wholesale level (where scanner data do not exist) and for geographic markets that span national borders (where comparable data may not be available), since other methods to derive elasticities, particularly those based on econometric estimation, may not be possible or may not be reliable.
The Hamiltonian Structures of the super KP hierarchy Associated with an Even Parity SuperLax Operator
We consider the even parity superLax operator for the supersymmetric KP
hierarchy of the form and obtain
the two Hamiltonian structures following the standard method of Gelfand and
Dikii. We observe that the first Hamiltonian structure is local and linear
whereas the second Hamiltonian structure is non-local and nonlinear among the
superfields appearing in the Lax operator. We discuss briefly on their
connections with the super algebra.Comment: 14 pages, Plain tex, IC/93/17
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The influence of physical and chemical linkage on the properties of nanocomposites
It has been shown by several groups that the mechanical and electrical behavior of composites changes quite substantially, and often beneficially, when the filler particle size is less than 100 nm in diameter. There is also good reason to believe that the interface between the embedded particulates and the polymer matrix holds the key to understanding the bulk phenomena observed. Materials based on an SiO2-polyolefin system have been formulated with functionalized particulates so as to affect the physical and chemical linkages. The agents used to achieve this include amino-silane, hexamethyl-disilazane and triethoxyvinylsilane. The emerging picture of the interface is supported by detailed dielectric spectroscopy and internal space charge assessment. The nature of the internal structure has been related to the bulk properties observed such as the breakdown strength, voltage endurance, and the measurement of internal charges resulting from interfacial polarization
Unification, Multiplets and Proton Decay
We make a detailed analysis of gauge coupling unification in supersymmetry.
When the Standard Model gauge group is embedded in a Grand Unified Theory, new
particles often appear below the GUT scale in order to predict the right
phenomenology at low energy. While these new particles are beyond the reach of
accelerator experiments, they change the prediction of \alpha_s. Here we
classify all the (SU(3)_C,SU(2)_L,U(1)_Y) representations which improve or
worsen the prediction. Running experimentally determined values of the coupling
constants at two loops we calculate the allowed range of masses of fields in
these representations. We explore the implication of these results in SU(5) and
SU(3)^3 (trinification) models. We discover that minimal trinification predicts
light triplet Higgs particles which lead to proton decay with a lifetime in the
vicinity of the current experimental bound.Comment: figures replaced, new calculations and references added. A
quantitative description of dependence of unification on varying input
parameters as well as varying the sparticle spectrum is added. This version
to appear in PR
Initial development of an ablative leading edge for the space shuttle orbiter
A state-of-the-art preliminary design for typical wing areas is developed. Seven medium-density ablators (with/without honeycomb, flown on Apollo, Prime, X15A2) are evaluated. The screening tests include: (1) leading-edge models sequentially subjected to ascent heating, cold soak, entry heating, post-entry pressure fluctuations, and touchdown shock, and (2) virgin/charred models subjected to bondline strains. Two honeycomb reinforced 30 pcf elastomeric ablators were selected. Roughness/recession degradation of low speed aerodynamics appears acceptable. The design, including attachments, substructure and joints, is presented
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