Did Dewey Presage the 1989 National Council of Teachers of Mathematics Standards?

The general theme of change in philosophy over time is due to traditional customs and beliefs failing to regulate society. This theme drove both John Dewey\u27s Progressive Movement and the creation of the Curriculum and Evaluation Standards for School Mathematics (1989) by the National Council of Teachers of Mathematics (NCTM). The remarkable similarity in thought between Dewey\u27s writings and the Standards is the basis for this paper. The point of view is from the Standards looking back to find Dewey\u27s similar ideas. Although Dewey\u27s views of mathematics per se are not extensively explicated, his overarching views on learning content resonate strongly with those of the NCTM document. There is common focus on the individual, learning as doing, developing power of each student, the use of worthwhile tasks, views on curriculum, and the need for more experienced teachers and peers to stretch and pull the student into arenas of exploration. If John Dewey were alive today, what would he have to say about the standards movement? There are a number of types of standards under consideration, with a variety of characteristics. In particular, what would he think of the NCTM C&E Standards? What is the background of the NCTM Standards? Where would Dewey agree with the NCTM Standards? Where would Dewey disagree with the NCTM Standards? There are four main sections comprising the body of this paper: the issue, the epistemology, the impetus for change, and the vision. The idea of standards, what does it mean to know, why change, and what are the related goals

Micro-Capsules in Shear Flow

This paper deals with flow-induced shape transitions of elastic capsules. The state of the art concerning both theory and experiments is briefly reviewed starting with dynamically induced small deformation of initially spherical capsules and the formation of wrinkles on polymerized membranes. Initially non-spherical capsules show tumbling and tank-treading motion in shear flow. Theoretical descriptions of the transition between these two types of motion assuming a fixed shape are at variance with the full capsule dynamics obtained numerically. To resolve the discrepancy, we expand the exact equations of motion for small deformations and find that shape changes play a dominant role. We classify the dynamical phase transitions and obtain numerical and analytical results for the phase boundaries as a function of viscosity contrast, shear and elongational flow rate. We conclude with perspectives on timedependent flow, on shear-induced unbinding from surfaces, on the role of thermal fluctuations, and on applying the concepts of stochastic thermodynamics to these systems.Comment: 34 pages, 15 figure

Phase transitions in simple and not so simple binary fluids

Compared to pure fluids, binary mixtures display a very diverse phase behavior, which depends sensitively on the parameters of the microscopic potential. Here we investigate the phase diagrams of simple model mixtures by use of a microscopic implementation of the renormalization group technique. First, we consider a symmetric mixture with attractive interactions, possibly relevant for describing fluids of molecules with internal degrees of freedom. Despite the simplicity of the model, slightly tuning the strength of the interactions between unlike species drastically changes the topology of the phase boundary, forcing or inhibiting demixing, and brings about several interesting features such as double critical points, tricritical points, and coexistence domains enclosing `islands' of homogeneous, mixed fluid. Homogeneous phase separation in mixtures can be driven also by purely repulsive interactions. As an example, we consider a model of soft particles which has been adopted to describe binary polymer solutions. This is shown to display demixing (fluid-fluid) transition at sufficiently high density. The nature and the physical properties of the corresponding phase transition are investigated.Comment: 6 pages + 3 figures, presented at the 5th EPS Liquid Matter Conference, Konstanz, 14-18 September 200

Membrane-transferring regions of gp41 as targets for HIV-1 fusion inhibition and viral neutralization

12 páginas, 4 figurasThe fusogenic function of HIV-1 gp41 transmembrane Env subunit relies on two different kinds of structural elements: i) a collapsible ectodomain structure (the hairpin or six-helix bundle) that opens and closes, and ii) two membrane- transferring regions (MTRs), the fusion peptide (FP) and the membrane-proximal external region (MPER), which ensure coupling of hairpin closure to apposition and fusion of cell and viral membranes. The isolation of naturally produced short peptides and neutralizing IgG-s, that interact with FP and MPER, respectively, and block viral infection, suggests that these conserved regions might represent useful targets for clinical intervention. Furthermore, MTR-derived peptides have been shown to be membrane-active. Here, it is discussed the potential use of these molecules and how the analysis of their membrane activity in vitro could contribute to the development of HIV fusion inhibitors and effective immunogensThe authors wish to thank financial support obtained from Spanish MICINN (BIO2008- 00772) (JLN) and University of the Basque Country (GIU 06/42 and DIPE08/12) (NH and JLN).Peer reviewe

Erziehung und sozialer Wandel - Brennpunkte sozialpädagogischer Forschung, Theoriebildung und Praxis. Eine Einführung in die Thematik des Beihefts

Verallgemeinernd wird im Beitrag festgestellt: "Es geht zunächst um die Vergegenwärtigung der Wandlungen und Veränderungen in den sozialen Problemlagen und Lebensverhältnissen der Adressaten der Sozialpolitik, wie sie sich im Zusammenhang der dramatischen Veränderungen auf der gesellschaftlichen Ebene in der zweiten Hälfte der neunziger Jahre darstellen; deswegen ist von den Erziehungsverhältnissen im sozialen Wandel die Rede... Es geht um die Frage, wie Erziehungs- und Bildungsverhältnisse im Zeichen und im Kontext gesellschaftlicher Wandlungsprozesse sich verändern und welche Problemlagen daraus resultieren." (DIPF/Sch.

Physics of the dynamic ergodic divertor

The Dynamic Ergodic Divertor (DED) of TEXTOR is presently being installed. It consists of sixteen helically wound coils occupying about 30% of the wall at the HFS. The coils follow field lines on a “pre-selected” magnetic surface and are fed individually outside the vessel. A perturbation field is created by the electrical currents in the perturbation coils with Fourier components resonant to the magnetic surfaces. The stochastic boundary layer is generated in the outermost region of the plasma, which due to long and short connection lengths can be divided into ergodic and laminar regions. Field line tracing and mapping techniques were used to analyse properties of the TEXTOR-DED plasma boundary. The DED will operate with several frequencies (DC or AC up to 10 kHz). In the “dynamic” operation the convective heat flux is deposited to a large plasma-facing surface and forces are transferred to the plasma edge, what can introduce a differential rotation of the plasma