39,339 research outputs found
Analysis of a diffusive effective mass model for nanowires
We propose in this paper to derive and analyze a self-consistent model
describing the diffusive transport in a nanowire. From a physical point of
view, it describes the electron transport in an ultra-scaled confined
structure, taking in account the interactions of charged particles with
phonons. The transport direction is assumed to be large compared to the wire
section and is described by a drift-diffusion equation including effective
quantities computed from a Bloch problem in the crystal lattice. The
electrostatic potential solves a Poisson equation where the particle density
couples on each energy band a two dimensional confinement density with the
monodimensional transport density given by the Boltzmann statistics. On the one
hand, we study the derivation of this Nanowire Drift-Diffusion Poisson model
from a kinetic level description. On the other hand, we present an existence
result for this model in a bounded domain
The state of the responsible research and innovation programme: A case for its application in additive manufacturing
The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Many of the ethical issues of additive manufacturing (AM) are not well known or understood,
and there remains a policy vacuum that needs to be addressed. This paper aims to describe an approach that
has been applied successfully to other emerging technologies, referred to as the responsible research and
innovation (RRI) framework programme. A case is then made for the application of this approach in the AM
industry with an illustration of how it might be used
What explains the stock market's reaction to Federal Reserve policy?
This paper analyzes the impact of unanticipated changes in the Federal funds target on equity prices, with the aim of both estimating the size of the typical reaction, and understanding the reasons for the market's response. On average over the May 1989 to December 2001 sample, a "typical" unanticipated 25 basis point rate cut has been associated with a 1.3 percent increase in the S&P 500 composite index. The estimated response varies considerably across industries, with the greatest sensitivity observed in cyclical industries like construction, and the smallest in mining and utilities. Very little of the market's reaction can be attributed to policy's effects on the real rate of interest or future dividends, however. Instead, most of the response of the current excess return on equities can be traced to policy's impact on expected future excess returns.
The N=1 Supersymmetric Landau Problem and its Supersymmetric Landau Level Projections: the N=1 Supersymmetric Moyal-Voros Superplane
The N=1 supersymmetric invariant Landau problem is constructed and solved. By
considering Landau level projections remaining non trivial under N=1
supersymmetry transformations, the algebraic structures of the N=1
supersymmetric covariant non(anti)commutative superplane analogue of the
ordinary N=0 noncommutative Moyal-Voros plane are identified
What Explains the Stock Market's Reaction to Federal Reserve Policy?
This paper analyzes the impact of changes in monetary policy on equity prices, with the objectives both of measuring the average reaction of the stock market and also of understanding the economic sources of that reaction. We find that, on average, a hypothetical unanticipated 25-basis-point cut in the federal funds rate target is associated with about a one percent increase in broad stock indexes. Adapting a methodology due to Campbell (1991) and Campbell and Ammer (1993), we find that the effects of unanticipated monetary policy actions on expected excess returns account for the largest part of the response of stock prices.
Global Trade Models and Economic Policy Analyses: Relevance, Risks and Repercussions for Africa
Computable general equilibrium (CGE) models are widely used for trade policy analyses and recommendations. Simulation results from these models have also been used as a basis for offering advice to African countries on what positions to take in multilateral trade negotiations. There is however increasing discomfort with the use of these models for policy recommendations, especially in Africa. In this paper we compare the results of several CGE studies that examined the impact of potential Doha Round reforms on Africa and demonstrate that the results differ drastically both in terms of magnitude and direction. Part of the discrepancies in results can be explained by differences in database, model structure, and choice of parameters. Others are, however, difficult to explain because several studies either do not report key assumptions made or do not provide a clear description of how their framework differs from those in the literature. We also show that the modelling approach and the database used in most CGE studies do not take account of key features of African economies that have serious implications for the impact of trade reforms on Africa. Finally, we outline potential consequences of the misuse of CGE models for policy evaluation and suggest pitfalls to avoid if CGE model results are to be taken seriously by policy makers in Africa.Trade Reforms; CGE Models; Doha Round; Africa
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