Theory Development through Simulation: Extending coordination theory in crisis response

As a research method, simulation can be useful in coping with the lack of data or in designing experiments that would be too costly or risky otherwise. This is especially relevant in the domain of crisis response, where on top of the difficulty of controlling data gathering and experiments there is also a lack of theory, particularly in terms of coordination. We present a framework that guides the use of simulation as a method for theory development in this domain. We illustrate this framework with research in progress aimed at extending the theory of coordination in crisis response. A simulation model is built to operationalize the theory and enable improved understanding of coordination in crisis response

Validation of Crisis Response Simulation within the Design Science Framework

In design science research in information systems (DSRIS), validation is often neglected in exchange for an emphasis on evaluation. However, rigorous scientific contributions most often explicitly address validation. In order to address the complexity of validation within design science, an explicit recognition of the assumptions and methods used within the DSRIS framework is needed. In this paper we discuss an approach to validation in a research in progress aimed at theory development in coordination of crisis response, through the use of agent-based simulation. This enables validation to be discussed from the point of view of simulation, the agent-based approach and the domain of crisis response, underpinned by a hermeneutical epistemology. Other research endeavors within DSRIS can follow a similar strategy to deal with the issue of validation

Conotoxins as Tools to Understand the Physiological Function of Voltage-Gated Calcium (CaV) Channels

Voltage-gated calcium (CaV) channels are widely expressed and are essential for the completion of multiple physiological processes. Close regulation of their activity by specific inhibitors and agonists become fundamental to understand their role in cellular homeostasis as well as in human tissues and organs. CaV channels are divided into two groups depending on the membrane potential required to activate them: High-voltage activated (HVA, CaV1.1–1.4; CaV2.1–2.3) and Low-voltage activated (LVA, CaV3.1–3.3). HVA channels are highly expressed in brain (neurons), heart, and adrenal medulla (chromaffin cells), among others, and are also classified into subtypes which can be distinguished using pharmacological approaches. Cone snails are marine gastropods that capture their prey by injecting venom, “conopeptides”, which cause paralysis in a few seconds. A subset of conopeptides called conotoxins are relatively small polypeptides, rich in disulfide bonds, that target ion channels, transporters and receptors localized at the neuromuscular system of the animal target. In this review, we describe the structure and properties of conotoxins that selectively block HVA calcium channels. We compare their potency on several HVA channel subtypes, emphasizing neuronal calcium channels. Lastly, we analyze recent advances in the therapeutic use of conotoxins for medical treatments

Robust free-spurious formulation of high order 2.5 dimensional electromagnetic problems by using finite elements

The 3D Finite Elements Method (FEM) is an extensively accepted tool for the analysis and design of microwaves/millimetre circuits and antennas based on the use of complex materials and geometries. Despite the huge memory capacity and computation speed of the current informatics systems, the method still suffers from an expensive computational cost when the domain is 3D. In many practical structures, the knowledge of the behaviour of one field component introduces a symmetry in the formulations that allows to project the physical problem onto a bi-dimensional mesh. The result of the former is a dramatic increase of the speed and ease of handling of such kind of problems, achieving efficient tools for the computer assisted design of many complex structures used in the electrical engineering nowadays. Because nothing is free, this simplification in the computation of the numerical problems is reached after a modification into the formulation and discretization of the model in the sense to introduce the symmetry of the field component into the basis functions. Because we need the three field components, we must divide the basis functions in two sets; one keeps the vector character and is applied to approximate the transversal or meridian component of the electromagnetic field and the other set is used for the longitudinal or azimuthal component. Then, we have to work with two elements, one is vector and the other is scalar. Frequently they are called hybrid elements, or 2.5D elements. This type of problems has been intensively studied by many researchers along the last two decades [1], [2], [3], [4], [5], [6]. However, only lower order basis has been used and, since our knowledge, it has not been developed a theory linking the development of the function spaces for the cited two elements, vector and scalar which make up the hybrid elements. This is especially true when the order of the elements increases, producing the apparition of the frightened spurious modes. Besides of the lack of a robust method to obtain these higher order hybrid elements for the 2.5D problems, we consider that it is worth reviewing these procedures, trying to increase its reliability and robustness. It should be a priority to incorporate the use of higher-order elements to the discretization of 2.5D problems, as the last developments relative to pre and post processors, new and more powerful meshers and solvers. In this way we can develop new numerical tools facing the more complex geometries containing field singularities, diverse materials and multiscale details with curved boundaries that conform the structures that electrical engineers handle nowadays. This work is an extension with some new results of previous presented at [5], [7]. A complete study of the design of conical dielectric core horn antennas, ended by both, convex-plane and double-convex dielectric lens, is carried on, taking advantage of the robust performance of the developed methods