Learning the Art of Instructional Conversation: The Influence of Self-Assessment on Teachers\u27 Instructional Discourse in a Reading Clinic

Over 2 decades of sociolinguistic research describe the teacher\u27s powerful role in creating the communication system that supports students\u27 learning. Yet research evidence about how to prepare and develop professionals for this role beyond their natural discourse tendencies and style remains sparse. This study examined self-assessment as a means of teacher learning that develops teachers\u27 understanding and use of discourse strategies that support instructional conversation. Using a discourse analysis tool and related procedures (transcription, analysis, and interpretation), 9 teachers examined the conceptual and social functions of their talk from videotaped excerpts of tutorial instruction over 5 weeks. Although the teachers\u27 analyses did not grow more precise, their interpretations of their talk revealed a growing ability to treat their discourse as an object of knowledge. Repeated engagement in the 3-phase self-assessment activity may have provided a form of self-assistance that promoted conceptual understanding. Design features of the self-assessment activity as a learning structure are also discussed

Local ERM activation and dynamic growth cones at Schwann cell tips implicated in efficient formation of nodes of Ranvier

Nodes of Ranvier are specialized, highly polarized axonal domains crucial to the propagation of saltatory action potentials. In the peripheral nervous system, axo–glial cell contacts have been implicated in Schwann cell (SC) differentiation and formation of the nodes of Ranvier. SC microvilli establish axonal contact at mature nodes, and their components have been observed to localize early to sites of developing nodes. However, a role for these contacts in node formation remains controversial

SPH Simulations of Counterrotating Disk Formation in Spiral Galaxies

We present the results of Smoothed Particle Hydrodynamics (SPH) simulations of the formation of a massive counterrotating disk in a spiral galaxy. The current study revisits and extends (with SPH) previous work carried out with sticky particle gas dynamics, in which adiabatic gas infall and a retrograde gas-rich dwarf merger were tested as the two most likely processes for producing such a counterrotating disk. We report on experiments with a cold primary similar to our Galaxy, as well as a hot, compact primary modeled after NGC 4138. We have also conducted numerical experiments with varying amounts of prograde gas in the primary disk, and an alternative infall model (a spherical shell with retrograde angular momentum). The structure of the resulting counterrotating disks is dramatically different with SPH. The disks we produce are considerably thinner than the primary disks and those produced with sticky particles. The time-scales for counterrotating disk formation are shorter with SPH because the gas loses kinetic energy and angular momentum more rapidly. Spiral structure is evident in most of the disks, but an exponential radial profile is not a natural byproduct of these processes. The infalling gas shells that we tested produce counterrotating bulges and rings rather than disks. The presence of a considerable amount of preexisting prograde gas in the primary causes, at least in the absence of star formation, a rapid inflow of gas to the center and a subsequent hole in the counterrotating disk. In general, our SPH experiments yield stronger evidence to suggest that the accretion of massive counterrotating disks drives the evolution of the host galaxies towards earlier (S0/Sa) Hubble types.Comment: To appear in ApJ. 20 pages LaTex 2-column with 3 tables, 23 figures (GIF) available at this site. Complete gzipped postscript preprint with embedded figures available from http://tarkus.pha.jhu.edu/~thakar/cr3.html (3 Mb

Beyond Instructions to Disregard: When Objections Backfire and Interruptions Distract

Researchers have proposed many explanations for the replicated finding that jurors often fail to disregard evidence when instructed by a judge to do so. We propose a novel explanation: that the act of objecting may cause the effect because an objection (a) draws attention to the testimony and (b) heightens the perceived importance of the testimony (because of the implication that the objecting party wants to prevent jurors from using it). In previous studies, the act of objecting has always been confounded with the presence of the critical (objected-to) testimony. We devised two new experimental conditions that unconfound these factors. We found that whereas objections increase the use of objected-to (incriminating) testimony, random (non-objection) interruptions decrease use of this testimony. We conclude that, unlike random interruptions, an objection communicates to the jurors that an attorney is concerned about the objected-to testimony, increasing the perceived importance of that testimony

Phase relations between carotid pressure and ongoing electrocortical activity

The behavioral significance of changes in the cardiovascular system has been a major source of controversy in psychophysiology. In view of this, it is surprising that so few studies have examined the relationship between cardiac events and electrocortical (EEG) activity in human subjects. In the present study, this relationship was examined by comparing phase, amplitude and frequency of EEG activity sampled during systolic and diastolic pressure recorded from the carotid artery of resting subjects. The results indicated that rhythmic oscillations of the EEG (particularly those in the alpha range) were time-locked to the carotid pressure wave, and EEG samples taken during systolic and diastolic pressure were distincly out of phase. In addition, EEG activity sampled during systolic pressure was comprised of slower frequencies than EEG activity sampled during diastolic pressure. It was suggested that the relationship between cardiac events and behavior may be mediated in part by influences of the cardiovascular system on electrocortical rhythms.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25140/1/0000576.pd

The tissue distribution of Se 75 -selenouracil and Se 75 -selenourea

With the development of photoscanning clinical medicine now possesses a diagnostic technique in which further advances will depend heavily upon pharmacologic investigations of structure-distribution relations. In the present study the distribution of the selenium analogs of thiouracil and thiourea, labeled with Selenium-75, was studied in rabbits. After administration of either compound, high concentrations of Se 75 were found in the lung, liver and kidney. The concentration of Se 75 in the lungs after administration of these compounds, especially Se 75 -selenouracil, permitted visualization of the lungs in the living, intact animal by photoscanning. However, neither Se 75 -selenouracil nor Se 75 -selenourea permit pulmonary scans of high quality and these particular compounds are not recommended for trial in man. The possible relation of labelled compounds of this type, as well as certain other series of labeled compounds, to the problem of adrenal scanning is also discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46301/1/210_2004_Article_BF00246346.pd

A Disk Shadow Around the Young Star ASR 41 in NGC 1333

We present images of the young stellar object ASR 41 in the NGC 1333 star forming region at the wavelengths of H_alpha and [SII] and in the I, J, H, and K-bands. ASR 41 has the near-infrared morphology of an edge-on disk object, but appears an order of magnitude larger than typical systems of this kind. We also present detailed models of the scattering and radiative transfer in systems consisting of a young star surrounded by a proto-planetary disk, and the whole system being embedded in either an infalling envelope or a uniform molecular cloud. The best fit to the observed morphology can be achieved with a disk of approx. 200 AU diameter, immersed in a low density cloud. The low cloud density is necessary to stay below the sub-mm flux upper limits and to preserve the shadow cast by the disk via single scattering. The results demonstrate that ASR 41 is probably not inherently different from typical edge-on disk objects, and that its large apparent size is due to the shadow of a much smaller disk being projected into the surrounding dusty molecular material

Modelling the photopolarimetric variability of AA Tau

We present Monte Carlo scattered light models of a warped disc that reproduce the observed photopolarimetric variability of the classical T Tauri star, AA Tauri. For a system inclination of 75° and using an analytic description for a warped inner disc, we find that the shape and amplitude of the photopolarimetric variability are reproduced with a warp that occults the star, located at 0.07 au, amplitude 0.016 au, extending over radial and azimuthal ranges 0.0084 au and 145°. We also show a time sequence of high spatial resolution scattered light images, showing a dark shadow cast by the warp sweeping round the disc. Using a modified smooth particle hydrodynamics code, we find that a stellar dipole magnetic field of strength 5.2 kG, inclined at 30° to the stellar rotation axis can reproduce the required disc warping to explain the photopolarimetric variability of AA Ta

Des-tyrosine-dynorphin antagonizes morphine analgesia

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23809/1/0000047.pd

Boolean delay equations on networks: An application to economic damage propagation

We introduce economic models based on Boolean Delay Equations: this formalism makes easier to take into account the complexity of the interactions between firms and is particularly appropriate for studying the propagation of an initial damage due to a catastrophe. Here we concentrate on simple cases, which allow to understand the effects of multiple concurrent production paths as well as the presence of stochasticity in the path time lengths or in the network structure. In absence of flexibility, the shortening of production of a single firm in an isolated network with multiple connections usually ends up by attaining a finite fraction of the firms or the whole economy, whereas the interactions with the outside allow a partial recovering of the activity, giving rise to periodic solutions with waves of damage which propagate across the structure. The damage propagation speed is strongly dependent upon the topology. The existence of multiple concurrent production paths does not necessarily imply a slowing down of the propagation, which can be as fast as the shortest path.Comment: Latex, 52 pages with 22 eps figure