Using Sociocultural Theory to Guide Teacher Use and Integration of Instructional Technology in Two Professional Development Schools

This article demonstrates how sociocultural theories can be used to support strategic structuring of professional development activities for preservice and practicing teachers on technology use and integration. Examples are drawn from the authors\u27 experiences with teachers in two professional development schools that participated in a four-year Preparing Tomorrow\u27s Teachers in Technology (PT3) project. After a review of sociocultural theory and their context, the authors describe three activity systems in these schools: one for practicing teachers, one for preservice teachers, and a joint preservice/practicing teacher system. Important supports for use and integration of technology built into each of these activity systems included varied activities aimed at both beginning and advanced technology users, multiple levels of assisted performance, and a collaborative culture that offered numerous opportunities for shared work. Lessons learned and implications for teacher educators involved in similar partnerships are outlined

Field Experience as the Centerpiece of an Integrated Model for STEM Teacher Preparation

The purpose of this study was to provide a descriptive account of one pathway for preparing high-quality STEM (science, technology, engineering, and mathematics) teachers for work in high-need urban schools. In this account, we discuss the supports that STEM majors need in learning how to think about the content that they know well, through an educational perspective that focuses on teaching and learning. We also describe the approach that we use that integrates content knowledge, pedagogical content knowledge, and three extensive teaching co-op experiences to facilitate the transition from successful STEM undergraduate students to effective teachers of STEM content. We suggest that by using the teaching co-op experiences to both filter and reflect on content and pedagogical content knowledge, the STEM undergraduates develop a particularly strong foundation of knowledge for teaching

Normalization of Gravitational Acceleration Models

Unlike the uniform density spherical shell approximations of Newton, the con- sequence of spaceflight in the real universe is that gravitational fields are sensitive to the nonsphericity of their generating central bodies. The gravitational potential of a nonspherical central body is typically resolved using spherical harmonic approximations. However, attempting to directly calculate the spherical harmonic approximations results in at least two singularities which must be removed in order to generalize the method and solve for any possible orbit, including polar orbits. Three unique algorithms have been developed to eliminate these singularities by Samuel Pines [1], Bill Lear [2], and Robert Gottlieb [3]. This paper documents the methodical normalization of two1 of the three known formulations for singularity-free gravitational acceleration (namely, the Lear [2] and Gottlieb [3] algorithms) and formulates a general method for defining normalization parameters used to generate normalized Legendre Polynomials and ALFs for any algorithm. A treatment of the conventional formulation of the gravitational potential and acceleration is also provided, in addition to a brief overview of the philosophical differences between the three known singularity-free algorithms

Nursing Retention in Critical Care

The purpose of the study was to examine anticipated turnover in critical care nurses and if having previous nursing experience prior to working in critical care affects that turnover. Using the Anticipated Turnover Scale (ATS) by Hinson and Atwood, nurses that had been employed in the critical care areas five years or less were asked to participate. They were asked to complete the ATS and answer the question relating to previous nursing experience. Findings of the study indicated that the nurses with previous nursing experience before working in critical care had a higher ATS score than the nurses with no previous nursing experience. Recommendations from the study are to expand to a larger sample and consider other variables that may contribute to nursing retention in the critical care areas

Sediment destabilization by animal tubes

Laboratory flume ex periments we re conducted in order to test the influence on sediment e rodibility of varying densities of the tube-building polychaete worm Owenia fusiformis. Experiments were performed on isolated individuals, in order to measure approximate spatial limits of isolated tube effects, and on arrays of individuals at densities reported previously to be associated with stable beds...

Theory and observations: Model simulations of the period 1955-1985

The main objective of the theoretical studies presented here is to apply models of stratospheric chemistry and transport in order to understand the processes that control stratospheric ozone and that are responsible for the observed variations. The model calculations are intended to simulate the observed behavior of atmospheric ozone over the past three decades (1955-1985), for which there exists a substantial record of both ground-based and, more recently, satellite measurements. Ozone concentrations in the atmosphere vary on different time scales and for several different causes. The models described here were designed to simulate the effect on ozone of changes in the concentration of such trace gases as CFC, CH4, N2O, and CO2. Changes from year to year in ultraviolet radiation associated with the solar cycle are also included in the models. A third source of variability explicitly considered is the sporadic introduction of large amounts of NO sub x into the stratosphere during atmospheric nuclear tests

Resonant enhancement of the jump rate in a double-well potential

We study the overdamped dynamics of a Brownian particle in the double-well potential under the influence of an external periodic (AC) force with zero mean. We obtain a dependence of the jump rate on the frequency of the external force. The dependence shows a maximum at a certain driving frequency. We explain the phenomenon as a switching between different time scales of the system: interwell relaxation time (the mean residence time) and the intrawell relaxation time. Dependence of the resonant peak on the system parameters, namely the amplitude of the driving force A and the noise strength (temperature) D has been explored. We observe that the effect is well pronounced when A/D > 1 and if A/D 1 the enhancement of the jump rate can be of the order of magnitude with respect to the Kramers rate.Comment: Published in J. Phys. A: Math. Gen. 37 (2004) 6043-6051; 6 figure

The ecological significance of giant clams in coral reef ecosystems

AbstractGiant clams (Hippopus and Tridacna species) are thought to play various ecological roles in coral reef ecosystems, but most of these have not previously been quantified. Using data from the literature and our own studies we elucidate the ecological functions of giant clams. We show how their tissues are food for a wide array of predators and scavengers, while their discharges of live zooxanthellae, faeces, and gametes are eaten by opportunistic feeders. The shells of giant clams provide substrate for colonization by epibionts, while commensal and ectoparasitic organisms live within their mantle cavities. Giant clams increase the topographic heterogeneity of the reef, act as reservoirs of zooxanthellae (Symbiodinium spp.), and also potentially counteract eutrophication via water filtering. Finally, dense populations of giant clams produce large quantities of calcium carbonate shell material that are eventually incorporated into the reef framework. Unfortunately, giant clams are under great pressure from overfishing and extirpations are likely to be detrimental to coral reefs. A greater understanding of the numerous contributions giant clams provide will reinforce the case for their conservation