On the Birth of Isolas

Isolas are isolated, closed curves of solution branches of nonlinear problems. They have been observed to occur in the buckling of elastic shells, the equilibrium states of chemical reactors and other problems. In this paper we present a theory to describe analytically the structure of a class of isolas. Specifically, we consider isolas that shrink to a point as a parameter τ of the problem, approaches a critical value τ_0. The point is referred to as an isola center. Equations that characterize the isola centers are given. Then solutions are constructed in a neighborhood of the isola centers by perturbation expansions in a small parameter ε that is proportional to (τ-τo), with a appropriately determined. The theory is applied to a chemical reactor problem

Dependency structure matrix modelling for stakeholder value networks

This paper develops a qualitative/quantitative network approach, namely a “Stakeholder Value Network”, to understand the impacts of both direct and indirect relationships between stakeholders on the success of large engineering projects. Specifically, this paper explores the feasibility and benefit of applying the Dependency Structure Matrix (DSM) as the modelling platform for Stakeholder Value Networks. Further, an efficient algorithm is designed for computing indirect stakeholder influence and implemented in a case study for a multinational energy project. The results derived from this analysis are able to answer three fundamental questions for stakeholder management: What are the critical paths/themes for a project to engage other stakeholders? Who are the most important stakeholders for a project? How can the complexity of a large relationship network be reasonably managed

Activity in deep intermediate layer collicular neurons during interrupted saccades

Abstract The activity of neurons located in the deep intermediate and adjacent deep layers (hereafter called just deep intermediate layer neurons) of the superior colliculus (SC) in monkeys was recorded during saccades interrupted by electrical stimulation of the brainstem omnipause neuron (OPN) region. The goal of the experiment was to determine if these neurons maintained their discharge during the saccadic interruption, and, thus, could potentially provide a memory trace for the intended movement which ends accurately on target in spite of the perturbation. The collicular neurons recorded in the present study were located in the rostral three-fifths of the colliculus. Most of these cells tended to show considerable presaccadic activity during a delayed saccade paradigm, and, therefore, probably overlap with the population of SC cells called buildup neurons or prelude bursters in previous studies. The effect of electrical stimulation in the OPN region (which interrupted ongoing saccades) on the discharge of these neurons was measured by computing the percentage reduction in a cell's activity compared to that present during non-interrupted saccades. During saccade interruption about 70% of deep intermediate layer neurons experienced a major reduction (30% or greater) in their activity, but discharge recovered quickly after the termination of the stimulation as the eyes resumed their movement to finish the saccade on the target. Therefore, the pattern of activity recorded in most of the deep intermediate layer neurons during interrupted saccades qualitatively resembled that previously reported for the saccade-related burst neurons which tend to be located more dorsally in the intermediate layer. In contrast, some of our cells (30%) showed little or no perturbation in their activity caused by the saccade interrupting stimulation. Because all the more dorsally located burst neurons and the majority of our deep intermediate layer neurons show a total or major suppression in their discharge during interrupted saccades, it seems unlikely that the colliculus by itself could maintain an accurate memory of the desired saccadic goal or the remaining dynamic motor error required to account for the accuracy of the resumed movement which occurs following the interruption. However, it remains possible that the smaller proportion of our neurons whose activity was not perturbed during interrupted movements could play a role in the mechanisms underlying saccade accuracy in the interrupted saccade paradigm. Interrupted saccades have longer durations than normal saccades to the same target. Therefore, we investigated whether the discharge of our deeper collicular cells was also necessarily prolonged during interrupted saccades, and, if so, how the prolongation compared to the prolongation of the saccade. Sixty percent of our sample neurons showed a prolongation in discharge that was approximately the same as the prolongation in saccade duration (difference <15 ms in magnitude). The observation that temporal discharge in our neurons was perturbed to roughly match saccadic temporal perturbation suggests that dynamic feedback about ongoing saccadic motion is provided to the colliculus, but does not necessarily imply that this structure is the site responsible for the computation of dynamic motor error

Long-term AZT Exposure Alters the Metabolic Capacity of Cultured Human Lymphoblastoid Cells

The antiretroviral efficacy of 3′-azido-3′-deoxythymidine (AZT) is dependent upon intracellular mono-, di-, and triphosphorylation and incorporation into DNA in place of thymidine. Thymidine kinase 1 (TK-1) catalyzes the first step of this pathway. MOLT-3, human lymphoblastoid cells, were exposed to AZT continuously for 14 passages (P1–P14) and cultured for an additional 14 passages (P15–P28) without AZT. Progressive and irreversible depletion of the enzymatically active form of the TK-1 24-kDa monomer with loss of active protein was demonstrated during P1–P5 of AZT exposure. From P15 to P28, both the 24- and the 48-kDa forms of TK-1 were undetectable and a tetrameric 96-kDa form was present. AZT-DNA incorporation was observed with values of 150, 133, and 108 molecules of AZT/106 nucleotides at the 10μM plasma-equivalent AZT dose at P1, P5, and P14, respectively. An exposure-related increase in the frequency of micronuclei (MN) was observed in cells exposed to either 10 or 800μM AZT during P1–P14. Analysis of the cell cycle profile revealed an accumulation of S-phase cells and a decrease in G1-phase cells during exposure to 800μM AZT for 14 passages. When MOLT-3 cells were grown in AZT-free media (P15–P29), there was a reduction in AZT-DNA incorporation and MN formation; however, TK-1 depletion and the persistence of S-phase delay were unchanged. These data suggest that in addition to known mutagenic mechanisms, cells may become resistant to AZT partially through inactivation of TK-1 and through modulation of cell cycle components

Educational testing of an auditory display regarding seasonal variation of martian polar ice caps

Proceedings of the 9th International Conference on Auditory Display (ICAD), Boston, MA, July 7-9, 2003.During Fall 2002, planetary scientists and astronomy education researchers from the University of Arizona and the National Optical Astronomy Observatory collaborated with composer Marty Quinn of Design Rhythmics Sonification Research Lab in New Hampshire to create both a visual and auditory display of recent gamma ray data from Mars. This product will be used both to highlight the value of data from the current Mars 2001 Odyssey mission and to serve as a testbed for research into the use and effectiveness of auditory displays in science education. This paper provides background on the Mars data presented, an overview of the animation/sonification product, preliminary results from educational testing of the product, and future research plans. The authors hope to present both the sonification and preliminary results of educational research at the ICAD conference this summer

Rhetorical Transformations in Multimodal Advertising Texts: From General to Local Degree Zero

The use of rhetoric in advertising research has been steadily gaining momentum since the 1980’s. Coupled with an increased interest in multimodality and the multiple interactions among verbal, pictorial and auditory registers, as structural components of an ad filmic text, the hermeneutic tools furnished by traditional rhetoric have been expanded and elaborated. This paper addresses the fundamental question of how ad filmic texts assume signification from a multimodal rhetorical point of view, by engaging in a fruitful dialogue with various research streams within the wider semiotic discipline and consumer research. By critically addressing the context of analysis of a multimodal ad text in the course of the argumentation deployed by different approaches, such as Social Semiotics (Kress/Leeuwen 2001), Film Semiotics (i.e. Metz 1982, Carroll 1980, Branigan 1982), Visual Semiotics (i.e. Sonesson 2008; 2010, Eco 1972;1976;1986, Groupe " 1992), Consumer Research (i.e. Mick/McQuarrie 1999; 2004, Philips 2003, Scott 1994), the relative merits of a structuralist approach that prioritizes the distinction between local and general degree zero, as put forward by Groupe " (1992), are highlighted. Furthermore, the modes whereby rhetorical transformations are enacted are outlined, with view to deepening the conceptual tackling of degree zero of signification, while addressing its applicability to branding discourse and multimodal ad texts