A Presuppositional Critique of Constructivism

Educational theories have roots. They have roots in broader philosophies, conceptions of the nature of reality, and the theories utilized in classrooms to teach have implications for broader society. The author takes a presuppostitional view and shows that all systems have most basic beliefs that are un-provable. So at the heart of any form of interpretive schema or paradigm is faith in that schema. The author discusses the role of theories of truth, how fact-constructivism embraces a relativist position that is self-refuting, and ultimately is untenable absent a suspension of laws of logic. The author argues in favor of revelation from God as axiomatic and demonstrates how logic can exist on that basis, whereas on a secular basis, philosophy cannot generate any True facts whatsoever. The author then looks at the educational theory of constructivism and examines the theory and practices it endorses it in light of the presuppositional critique and concludes that the relativistic nature of constructivism precludes it from being a philosophically acceptable approach for the Christian

Parallel implementation of the TRANSIMS micro-simulation

This paper describes the parallel implementation of the TRANSIMS traffic micro-simulation. The parallelization method is domain decomposition, which means that each CPU of the parallel computer is responsible for a different geographical area of the simulated region. We describe how information between domains is exchanged, and how the transportation network graph is partitioned. An adaptive scheme is used to optimize load balancing. We then demonstrate how computing speeds of our parallel micro-simulations can be systematically predicted once the scenario and the computer architecture are known. This makes it possible, for example, to decide if a certain study is feasible with a certain computing budget, and how to invest that budget. The main ingredients of the prediction are knowledge about the parallel implementation of the micro-simulation, knowledge about the characteristics of the partitioning of the transportation network graph, and knowledge about the interaction of these quantities with the computer system. In particular, we investigate the differences between switched and non-switched topologies, and the effects of 10 Mbit, 100 Mbit, and Gbit Ethernet. keywords: Traffic simulation, parallel computing, transportation planning, TRANSIM

Experiences with a simplified microsimulation for the Dallas/Fort Worth area

We describe a simple framework for micro simulation of city traffic. A medium sized excerpt of Dallas was used to examine different levels of simulation fidelity of a cellular automaton method for the traffic flow simulation and a simple intersection model. We point out problems arising with the granular structure of the underlying rules of motion.Comment: accepted by Int.J.Mod.Phys.C, 20 pages, 14 figure

Rising methane gas bubbles form massive hydrate layers at the seafloor

Extensive methane hydrate layers are formed in the near-surface sediments of the Cascadia margin. An undissociated section of such a layer was recovered at the base of a gravity core (i.e. at a sediment depth of 120 cm) at the southern summit of Hydrate Ridge. As a result of salt exclusion during methane hydrate formation, the associated pore waters show a highly elevated chloride concentration of 809 mM. In comparison, the average background value is 543 mM. A simple transport-reaction model was developed to reproduce the Cl- observations and quantify processes such as hydrate formation, methane demand, and fluid flow. From this first field observation of a positive Cl- anomaly, high hydrate formation rates (0.15–1.08 mol cm-2 a-1) were calculated. Our model results also suggest that the fluid flow rate at the Cascadia accretionary margin is constrained to 45–300 cm a-1. The amount of methane needed to build up enough methane hydrate to produce the observed chloride enrichment exceeds the methane solubility in pore water. Thus, most of the gas hydrate was most likely formed from ascending methane gas bubbles rather than solely from CH4 dissolved in the pore water

A note on couette flow of nematic crystals according to the Ericksen–Leslie theory

In order to model the flow of nematic crystals, the theoretical framework according to Ericksen and Leslie is applied. The essentials of the theory are compiled and then specialized to Couette flow. The profiles for linear velocity and orientation angle will be computed and, in particular, we shall also study the rise in temperature due to viscous dissipation, which is frequently ignored by mechanicians. Analytical and numerical solutions for the fields are derived for different boundary conditions and will subsequently be discussed.TU Berlin, Open-Access-Mittel - 201

The dynamics of iterated transportation simulations

Iterating between a router and a traffic micro-simulation is an increasibly accepted method for doing traffic assignment. This paper, after pointing out that the analytical theory of simulation-based assignment to-date is insufficient for some practical cases, presents results of simulation studies from a real world study. Specifically, we look into the issues of uniqueness, variability, and robustness and validation. Regarding uniqueness, despite some cautionary notes from a theoretical point of view, we find no indication of ``meta-stable'' states for the iterations. Variability however is considerable. By variability we mean the variation of the simulation of a given plan set by just changing the random seed. We show then results from three different micro-simulations under the same iteration scenario in order to test for the robustness of the results under different implementations. We find the results encouraging, also when comparing to reality and with a traditional assignment result. Keywords: dynamic traffic assignment (DTA); traffic micro-simulation; TRANSIMS; large-scale simulations; urban planningComment: 24 pages, 7 figure

Polymeric implant materials for the reconstruction of tracheal and pharyngeal mucosal defects in head and neck surgery

The existing therapeutical options for the tracheal and pharyngeal reconstruction by use of implant materials are described. Inspite of a multitude of options and the availability of very different materials none of these methods applied for tracheal reconstruction were successfully introduced into the clinical routine. Essential problems are insufficiencies of anastomoses, stenoses, lack of mucociliary clearance and vascularisation. The advances in Tissue Engineering (TE) offer new therapeutical options also in the field of the reconstructive surgery of the trachea. In pharyngeal reconstruction far reaching developments cannot be recognized at the moment which would allow to give a prognosis of their success in clinical application. A new polymeric implant material consisting of multiblock copolymers was applied in our own work which was regarded as a promising material for the reconstruction of the upper aerodigestive tract (ADT) due to its physicochemical characteristics. In order to test this material for applications in the ADT under extreme chemical, enzymatical, bacterial and mechanical conditions we applied it for the reconstruction of a complete defect of the gastric wall in an animal model. In none of the animals tested either gastrointestinal complications or negative systemic events occurred, however, there was a multilayered regeneration of the gastric wall implying a regular structured mucosa

A proof of the simple connectivity at infinity of Out F4

AbstractA finitely presented group G is said to be simply connected at infinity if, for any compact set C in the universal cover X̃ for the standard 2-complex for G, there exists a compact set D such that any loop in X̃⧹D is homotopically trivial in X̃⧹C. Suppose that F4 is a free group on four generators, AutF4 its automorphism group, and InnF4 the subgroup of inner automorphisms. We use direct, elementary means to show that the outer automorphism group of rank 4, AutF4/InnF4 is simply connected at infinity