843 research outputs found
Universal and Non-Universal First-Passage Properties of Planar Multipole Flows
The dynamics of passive Brownian tracer particles in steady two-dimensional
potential flows between sources and sinks is investigated. The first-passage
probability, , exhibits power-law decay with a velocity-dependent
exponent in radial flow and an order-dependent exponent in multipolar flows.
For the latter, there also occur diffusive ``echo'' shoulders and exponential
decays associated with stagnation points in the flow. For spatially extended
dipole sinks, the spatial distribution of the collected tracer is independent
of the overall magnitude of the flow field.Comment: 7 pages, LaTe
Optimized energy calculation in lattice systems with long-range interactions
We discuss an efficient approach to the calculation of the internal energy in
numerical simulations of spin systems with long-range interactions. Although,
since the introduction of the Luijten-Bl\"ote algorithm, Monte Carlo
simulations of these systems no longer pose a fundamental problem, the energy
calculation is still an O(N^2) problem for systems of size N. We show how this
can be reduced to an O(N logN) problem, with a break-even point that is already
reached for very small systems. This allows the study of a variety of, until
now hardly accessible, physical aspects of these systems. In particular, we
combine the optimized energy calculation with histogram interpolation methods
to investigate the specific heat of the Ising model and the first-order regime
of the three-state Potts model with long-range interactions.Comment: 10 pages, including 8 EPS figures. To appear in Phys. Rev. E. Also
available as PDF file at
http://www.cond-mat.physik.uni-mainz.de/~luijten/erikpubs.htm
Elucidation of Beta-Oxidation Pathways in Ralstonia Eutropha H16 by Examination of Global Gene Expression
Ralstonia eutropha H16 is capable of growth and polyhydroxyalkanoate production on plant oils and fatty acids. However, little is known about the triacylglycerol and fatty acid degradation pathways of this bacterium. We compare whole-cell gene expression levels of R. eutropha H16 during growth and polyhydroxyalkanoate production on trioleate and fructose. Trioleate is a triacylglycerol that serves as a model for plant oils. Among the genes of note, two potential fatty acid ÎČ-oxidation operons and two putative lipase genes were shown to be upregulated in trioleate cultures. The genes of the glyoxylate bypass also exhibit increased expression during growth on trioleate. We observed that single ÎČ-oxidation operon deletion mutants of R. eutropha could grow using palm oil or crude palm kernel oil as the sole carbon source, regardless of which operon was present in the genome, but a double mutant was unable to grow under these conditions. A lipase deletion mutant did not exhibit a growth defect in emulsified oil cultures but did exhibit a phenotype in cultures containing nonemulsified oil. Mutants of the glyoxylate shunt gene for isocitrate lyase were able to grow in the presence of oils, while a malate synthase (aceB) deletion mutant grew more slowly than wild type. Gene expression under polyhydroxyalkanoate storage conditions was also examined. Many findings of this analysis confirm results from previous studies by our group and others. This work represents the first examination of global gene expression involving triacylglycerol and fatty acid catabolism genes in R. eutropha.Malaysia-MIT Biotechnology Partnership Programm
Enabling Next Generation Dark Energy and Epoch of Reionization Radio Observatories with the MOFF Correlator
Proposed 21 cm cosmology observatories for studying the epoch of reionization
(z ~6-15) and dark energy (z ~0-6) envision compact arrays with tens of
thousands of antenna elements. Fully correlating this many elements is
computationally expensive using traditional XF or FX correlators, and has led
some groups to reconsider direct imaging/FFT correlators. In this paper we
develop a variation of the direct imaging correlator we call the MOFF
correlator. The MOFF correlator shares the computational advantages of a direct
imaging correlator, while avoiding a number of its shortcomings. In particular
the MOFF correlator makes no constraints on the antenna arrangement or type,
provides a fully calibrated output image including widefield polarimetry and
non-coplanar baseline effects, and can be orders-of-magnitude more efficient
than XF or FX correlators for compact radio cosmology arrays.Comment: Version accepted for publication in PASP (delay due to author's
distraction). Includes a number of advancements and refinements, including
the feedback calibration technique and a clearer development. If you
downloaded previous version please upgrade to this on
Other PeopleâS Money: A Visual Technology for Teaching Corporate Restructuring Cross-Functionally
This article presents a detailed plan for using the movie Other People's Money as an integrative technology to teach organizational behavior and finance concepts crossfunctionally. The movie depicts corporate restructuring issues in a comic manner, while still conveying a message. It incorporates topics such as differing organizational models and perpectives, leadership, managerial goals, and stakeholder needs/wants. It also helps students learn about mergers and acquisitions including topics like takeovers, tender offers, and greenmail while stimulating thinking aout complex ethical issues. This teaching tool can be incorporated in undergraduate or graduate business classes, or as a module for management education in corporate settings. The teaching notes include a vocabulary list, suggested stopping points with discussion questions, and a set of postmovie questions to reinforce related concepts and motivate further study.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68685/2/10.1177_105256299902300106.pd
On the Metric Dimension of Cartesian Products of Graphs
A set S of vertices in a graph G resolves G if every vertex is uniquely
determined by its vector of distances to the vertices in S. The metric
dimension of G is the minimum cardinality of a resolving set of G. This paper
studies the metric dimension of cartesian products G*H. We prove that the
metric dimension of G*G is tied in a strong sense to the minimum order of a
so-called doubly resolving set in G. Using bounds on the order of doubly
resolving sets, we establish bounds on G*H for many examples of G and H. One of
our main results is a family of graphs G with bounded metric dimension for
which the metric dimension of G*G is unbounded
Predicting decoherence in discrete models
The general aim of this paper is to supply a method to decide whether a
discrete system decoheres or not, and under what conditions decoherence occurs,
with no need of appealing to computer simulations to obtain the time evolution
of the reduced state. In particular, a lemma is presented as the core of the
method.Comment: 8 pages, 2 figure
Does franchising create value? An analysis of the financial performance of US public restaurant firms
Author's OriginalIt is commonly believed that the franchising method of distribution provides strategic and operational benefits to the companies that adopt it. These benefits should result in superior financial performance as compared to that of firms that do not use franchising. Yet, the empirical evidence of the effects of franchising on financial performance is sparse and mixed. The purpose of this paper is to further examine the empirical evidence of the impact of franchising on a firmâs financial performance by using performance metrics (Economic Value Added and Market Value Added) that are extensively used in corporate finance. This study focuses on the US public restaurant sector. The results provide some evidence that franchising firms create more market and economic value than do non-franchising firms.
A revised version of this paper has since been published in the International Journal of Hospitality and Tourism Administration. Please use this version in your citations.Aliouche, E. & Schlentrich, U. (2009). Does Franchising Create Value? An Analysis of the Financial Performance of US Public Restaurant Firms. International Journal of Hospitality & Tourism Administration, 10(2), 93-10
A system dynamics model of capital structure policy for firm value maximization
The complexity surrounding the maximization of firm value agenda demands a comprehensive causal model that effectively embeds the intertwining relationships of the variables and the policies involved. System dynamics provides an appropriate methodology to model and simulate such complex relationships to facilitate decision making in a complex business environment. The objective of the study is to analyze the impact of capital structure policy, being a key managerial decision, on the firm value. For this purpose, the study develops a system dynamicsâbased corporate planning model for an oil firm, including the operational as well as financial processes. Various scenarios and capital structure policies have been designed and simulated to identify the policy that helps in increasing the firm value. The results demonstrate that increase in debt percentage in capital structure mix increase the firm value.publishedVersio
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