What Next for Chaos Theory? From Metaphor to Phase Space

In the management and social sciences literature, chaos theory has been used primarily as a metaphor to understand organizational phenomena. Using metaphors to understand organizations is a novel idea that has gained much acceptance, thanks to the pioneering work of Morgan (1986). However, chaos theory\u27s value as a metaphor has been overused and offers little that cannot already be explained using existing theories and frameworks. Because chaos theory is a mathematical theory, we believe its mathematical principles offer the greatest application to the management literature. In this paper, we offer the use of phase space, a tool of chaos theory, as a way to analyze firm performance

In Pursuit of Crisis Readiness: An Examination of Managerial Characteristics, Firm Size, Industry Domain and Strategic Type within the Miles and Snow Framework

A crisis refers to an unpredictable event that can seriously threaten an organization. Crisis readiness is an integral part of the crisis management process and refers to the level of preparedness an organization possesses in response to a potential catastrophic event. Findings from a survey of 275 managers in the United States revealed that top managers with production/engineering and general management backgrounds reported higher degrees of crisis readiness capabilities than did their counterparts with other backgrounds. Likewise, higher levels of crisis readiness were reported in larger, manufacturing organizations than in smaller, service organizations

Vertical Separation of Telecommunications Networks: Evidence from Five Countries

The widespread adoption of mandatory unbundling in telecommunications markets has led to growing interest in mandatory functional separation, i.e., separation of upstream network operations from downstream retail operations. Since 2002, vertical separation has been implemented in five OECD countries: Australia, Italy, New Zealand, Sweden, and the United Kingdom. In 2008, the International Telecommunications Union noted a tremendous amount of interest in functional separation around the world; and, in April 2009, the European Parliament held its second reading on a new regulatory framework that embraces functional separation as an exceptional measure. While the U.S. does not currently require unbundling of broadband telecommunications networks, at least one influential group is advocating both unbundling and vertical separation for U.S. network operators. In this context, this study examines mandatory vertical separation in telecommunications markets from both a theoretical and an empirical perspective. The theoretical case against vertical separation is very strong, predicting in particular that mandated separation will discourage innovation and investment in new technologies. The empirical evidence tends to confirm these predictions, suggesting that overall, vertical separation is likely to impose significant costs without measurably increasing broadband penetration

Vertical Separation of Telecommunications Networks: Evidence from Five Countries

The widespread adoption of mandatory unbundling in telecommunications markets has led to growing interest in mandatory functional separation, i.e., separation of upstream network operations from downstream retail operations. Since 2002, vertical separation has been implemented in five OECD countries: Australia, Italy, New Zealand, Sweden, and the United Kingdom. In 2008, the International Telecommunications Union noted a tremendous amount of interest in functional separation around the world; and, in April 2009, the European Parliament held its second reading on a new regulatory framework that embraces functional separation as an exceptional measure. While the U.S. does not currently require unbundling of broadband telecommunications networks, at least one influential group is advocating both unbundling and vertical separation for U.S. network operators. In this context, this study examines mandatory vertical separation in telecommunications markets from both a theoretical and an empirical perspective. The theoretical case against vertical separation is very strong, predicting in particular that mandated separation will discourage innovation and investment in new technologies. The empirical evidence tends to confirm these predictions, suggesting that overall, vertical separation is likely to impose significant costs without measurably increasing broadband penetration

Reverse taxonomy for elucidating diversity of insect-associated nematodes: a case study with termites

BACKGROUND: The molecular operational taxonomic unit(MOTU)has recently been applied to microbial and microscopic animal biodiversity surveys. However, in many cases, some of the MOTUs cannot be definitively tied to any of the taxonomic groups in current databases. To surmount these limitations, the concept of "reverse taxonomy" has been proposed, i.e. to primarily list the MOTUs with morphological information, and then identify and/or describe them at genus/species level using subsamples or by re-isolating the target organisms. Nevertheless, the application of "reverse taxonomy" has not been sufficiently evaluated. Therefore, the practical applicability of "reverse taxonomy" is tested using termite-associated nematodes as a model system for phoretic/parasitic organisms which have high habitat specificity and a potential handle (their termite host species) for re-isolation attempts. METHODOLOGY: Forty-eight species (from 298 colonies) of termites collected from the American tropics and subtropics were examined for their nematode associates using the reverse taxonomy method and culturing attempts (morphological identification and further sequencing efforts). The survey yielded 51 sequence types (= MOTUs) belonging to 19 tentatively identified genera. Within these, four were identified based on molecular data with preliminary morphological observation, and an additional seven were identified or characterized from successful culturing, leaving eight genera unidentified. CONCLUSIONS: That 1/3 of the genera were not successfully identified suggests deficiencies in the depth of available sequences in the database and biological characters, i.e. usually isolated as phoretic/parasitic stages which are not available for morphological identification, and too many undiscovered lineages of nematodes. Although there still is the issue of culturability of nematodes, culturing attempts could help to make reverse taxonomy methods more effective. However, expansion of the database, i.e., production of more DNA barcodes tied to biological information by finding and characterizing additional new and known lineages, is necessary for analyzing functional diversity.Natsumi Kanzaki, Robin M. Giblin-Davis, Rudolf H. Scheffrahn, Hisatomo Taki, Alejandro Esquivel, Kerrie A. Davies and E. Allen Herr

On the Path Integral in Imaginary Lobachevsky Space

The path integral on the single-sheeted hyperboloid, i.e.\ in $D$-dimensional imaginary Lobachevsky space, is evaluated. A potential problem which we call ``Kepler-problem'', and the case of a constant magnetic field are also discussed.Comment: 16 pages, LATEX, DESY 93-14

Cdk5 regulates the phosphorylation of tyrosine 1472 NR2B and the surface expression of NMDA receptors

NMDA receptors (NMDARs) are a major class of ionotropic glutamate receptors that can undergo activity-dependent changes in surface expression. Clathrin-mediated endocytosis is a mechanism by which the surface expression of NR2B-containing NMDA receptors is regulated. The C terminus of the NMDA receptor subunit NR2B contains the internalization motif YEKL, which is the binding site for the clathrin adaptor AP-2. The tyrosine (Y1472) within the YEKL motif is phosphorylated by the Src family of kinases and this phosphorylation inhibits the binding of AP-2 and promotes surface expression of NMDA receptors. Cdk5 is a serine/threonine kinase that has been implicated in synaptic plasticity, learning, and memory. Here we demonstrate that inhibition of Cdk5 results in increased phosphorylation of Y1472 NR2B at synapses and decreased binding of NR2B to beta2-adaptin, a subunit of AP-2, thus blocking the activity-dependent endocytosis of NMDA receptors. Furthermore, we show that inhibition of Cdk5 increases the binding of Src to postsynaptic density-95 (PSD-95), and that expression of PSD-95 facilitates the phosphorylation of Y1472 NR2B by Src. Together, these results suggest a model in which inhibition of Cdk5 increases the binding of Src to PSD-95 and the phosphorylation of Y1472 NR2B by Src, which results in decreased binding of NR2B to AP-2, and NR2B/NMDAR endocytosis. This study provides a novel molecular mechanism for the regulation of the surface expression of NR2B-containing NMDA receptors and gives insight into the Cdk5-dependent regulation of synaptic plasticity

Dynamical response of the "GGG" rotor to test the Equivalence Principle: theory, simulation and experiment. Part I: the normal modes

Recent theoretical work suggests that violation of the Equivalence Principle might be revealed in a measurement of the fractional differential acceleration $\eta$ between two test bodies -of different composition, falling in the gravitational field of a source mass- if the measurement is made to the level of $\eta\simeq 10^{-13}$ or better. This being within the reach of ground based experiments, gives them a new impetus. However, while slowly rotating torsion balances in ground laboratories are close to reaching this level, only an experiment performed in low orbit around the Earth is likely to provide a much better accuracy. We report on the progress made with the "Galileo Galilei on the Ground" (GGG) experiment, which aims to compete with torsion balances using an instrument design also capable of being converted into a much higher sensitivity space test. In the present and following paper (Part I and Part II), we demonstrate that the dynamical response of the GGG differential accelerometer set into supercritical rotation -in particular its normal modes (Part I) and rejection of common mode effects (Part II)- can be predicted by means of a simple but effective model that embodies all the relevant physics. Analytical solutions are obtained under special limits, which provide the theoretical understanding. A simulation environment is set up, obtaining quantitative agreement with the available experimental data on the frequencies of the normal modes, and on the whirling behavior. This is a needed and reliable tool for controlling and separating perturbative effects from the expected signal, as well as for planning the optimization of the apparatus.Comment: Accepted for publication by "Review of Scientific Instruments" on Jan 16, 2006. 16 2-column pages, 9 figure

Inviscid dynamical structures near Couette flow

Consider inviscid fluids in a channel {-1<y<1}. For the Couette flow v_0=(y,0), the vertical velocity of solutions to the linearized Euler equation at v_0 decays in time. At the nonlinear level, such inviscid damping has not been proved. First, we show that in any (vorticity) H^{s}(s<(3/2)) neighborhood of Couette flow, there exist non-parallel steady flows with arbitrary minimal horizontal period. This implies that nonlinear inviscid damping is not true in any (vorticity) H^{s}(s<(3/2)) neighborhood of Couette flow and for any horizontal period. Indeed, the long time behavior in such neighborhoods are very rich, including nontrivial steady flows, stable and unstable manifolds of nearby unstable shears. Second, in the (vorticity) H^{s}(s>(3/2)) neighborhood of Couette, we show that there exist no non-parallel steadily travelling flows v(x-ct,y), and no unstable shears. This suggests that the long time dynamics in H^{s}(s>(3/2)) neighborhoods of Couette might be much simpler. Such contrasting dynamics in H^{s} spaces with the critical power s=(3/2) is a truly nonlinear phenomena, since the linear inviscid damping near Couette is true for any initial vorticity in L^2