A Model for Equity-Oriented PreK-12 Engineering

In this paper, we address the societally important issue of developing a more equitable approach to preK-12 engineering education. Our primary emphasis is on K-8 grades—a time when first impressions of engineering may be developed. Calls for increased participation by all students, including those who have been historically marginalized, motivate the need for theoretically grounded ways of developing and assessing educational programs. This paper draws from sociocultural learning theory and applies four theoretical and empirical analyses to derive design principles for equity that can inform curriculum, instruction, and assessment of preK-12 engineering education programs. We present a model for equity-oriented preK-12 engineering learning and delineate its dimensions and principles, which include socially engaged engineering, authentic engineering practices, asset-oriented pedagogies, and student engineering identity. We illustrate each with examples and discuss ways of implementing equity-oriented engineering curricula

Socially Engaged Engineering: A Framework for K-8 Education

Socially engaged engineering provides for student learning of the design, analysis, and practices of engineering as well as the ways that engineering is situated in sociocultural contexts. This paper provides a conceptual framework regarding socially engaged engineering for K-8 educators, researchers, and curriculum designers. The framework identifies ways to support youth learning of engineering and considerations of technical, social, environmental, and ethical dimensions of engineering. As engineering enters K-8 educational settings, it is important to introduce the discipline in equity-oriented ways. We draw from the field of engineering for social justice to build this framework for examining engineering at the macro-, meso-, and microscales. Situating engineering in sociocultural contexts can be motivating to learners and provide perspectives on the nature of engineering. Our framework was concurrently designed with Youth Engineering Solutions (YES; https://YouthEngineeringSolutions.org) curricular units. To test the applicability of our principles, we applied them to K-8 YES curricula for school and out-of-school environments. Through the coevolution of principles and curricular materials, we developed age-appropriate learning objectives for three levels—lower elementary, upper elementary, and middle school. This paper shares the principles and progression, showing worked examples from curricula to demonstrate how the principles translate into curricular resources. We discuss constraints to the implementation of socially engaged engineering curricula, including those imposed in educational settings and the ideological assumptions about science, engineering, and STEM disciplines

The Role of Social Movements in the Macro Political System

One of the central concepts in the study of social movements is that of the “Protest Cycle” (e.g., Tarrow 1998). The imagery of the Cycle is that of heightened protests, across issue areas and groups. Scholars have connected its rise to openings in the Political Opportunity Structure, which signals to early risers that the time may be ripe for collective action (e.g., Tarrow 1998). We find it striking that this core idea in the social movements literature has not been connected more explicitly to the literature on public opinion. This is especially striking because social movement scholars have begun to explicitly address the role of public opinion in their models (e.g., Soule and Olzak 2004; Soule and King 2006). Suppose that ideological social movements, taken as a whole, rise and fall across time in a predictable fashion. Perhaps the effects of these movements on public opinion and policy are also predictable, as some have argued (e.g., Burstein and Linton 2002). In that case, social movements play a vital role in connecting public opinion to policy. How can this be the case? Public opinion can be summarized as policy mood (e.g. Erikson, MacKuen and Stimson 2002). It turns out that at the national level, people’s preferences regarding the degree to which they think government should be more or less active moves over time in liberal and conservative directions. Policy mood causes national election outcomes, which in turn causes how liberal or conservative the legislation is that Congress passes. Policy mood should matter for social movements, as well . Dynamic policy mood presents social movement organizers with opportunities; when policy mood is liberal, liberal social movements have more of an opportunity to be successful because the issues they care about will receive more support from the American people (Soule and Olzak 2004). Liberal social movements will then rise, leading to greater policy success (the opposite will be true for conservative social movements). However, the activism of these rising social movements leads to an ideological backlash, which in turn moves public mood in the opposite direction in an effort to find balance. We test our hypotheses using a data set of public protest events that records protest events for each day from 1960 to 1995 ( see a data source summary in Soule and Davenport 2009 ). The evidence supports our hypotheses, indicating that social movements play an important role in the macro political system

NOX1 and NOX4 are required for the differentiation of mouse F9 cells into extraembryonic endoderm

Mouse F9 cells differentiate to primitive endoderm (PrE) when treated with retinoic acid (RA). Differentiation is accompanied by increased reactive oxygen species (ROS) levels, and while treating F9 cells with antioxidants attenuates differentiation, H2O2 treatment alone is sufficient to induce PrE. We identified the NADPH oxidase (NOX) complexes as candidates for the source of this endogenous ROS, and within this gene family, and over the course of differentiation, Nox1 and Nox 4 show the greatest upregulation induced by RA. Gata6, encoding a master regulator of extraembryonic endoderm is also up-regulated by RA and we provide evidence that NOX1 and NOX4 protein levels increase in F9 cells overexpressing Gata6. Pan-NOX and NOX1-specific inhibitors significantly reduced the ability of RA to induce PrE, and this was recapitulated using a genetic approach to knockdown Nox1 and/or Nox4 transcripts. Interestingly, overexpressing either gene in untreated F9 cells did not induce differentiation, even though each elevated ROS levels. Thus, the data suggests that ROS produced during PrE differentiation is dependent in part on increased NOX1 and NOX4 levels, which is under the control of GATA6. Furthermore, these results suggest that the combined activity of multiple NOX proteins is necessary for the differentiation of F9 cells to primitive endoderm

Circulating gastrin is increased in hemochromatosis

AbstractGastric acid production is important in intestinal iron absorption. The peptide hormone gastrin exists in both amidated and non-amidated forms, which stimulate and potentiate gastric acid secretion, respectively. Since non-amidated gastrins require ferric ions for biological activity in vitro, this study investigated the connection between iron status and gastrin by measurement of circulating gastrin concentrations in mice and humans with hemochromatosis. Gastrin concentrations are increased in the plasma and gastric mucosa of Hfe−/− mice, and in the sera of humans with HFE-related hemochromatosis. The discovery of a relationship between iron status and circulating gastrin concentrations opens a new perspective on the mechanisms of iron homeostasis

Inhibition of Rho kinase regulates specification of early differentiation events in P19 embryonal carcinoma stem cells

Background: The Rho kinase pathway plays a key role in many early cell/tissue determination events that take place in embryogenesis. Rho and its downstream effector Rho kinase (ROCK) play pivotal roles in cell migration, apoptosis (membrane blebbing), cell proliferation/cell cycle, cell-cell adhesion and gene regulation. We and others have previously demonstrated that inhibition of ROCK blocks endoderm differentiation in embryonal carcinoma stem cells, however, the effect of ROCK inhibition on mesoderm and ectoderm specification has not been fully examined. In this study, the role of ROCK within the specification and differentiation of all three germ layers was examined. Methodology/Principal Findings: P19 cells were treated with the specific ROCK inhibitor Y-27623, and increase in differentiation efficiency into neuro-ectodermal and mesodermal lineages was observed. However, as expected a dramatic decrease in early endodermal markers was observed when ROCK was inhibited. Interestingly, within these ROCK-inhibited RA treated cultures, increased levels of mesodermal or ectodermal markers were not observed, instead it was found that the pluripotent markers SSEA-1 and Oct-4 remained up-regulated similar to that seen in undifferentiated cultures. Using standard and widely accepted methods for reproducible P19 differentiation into all three germ layers, an enhancement of mesoderm and ectoderm differentiation with a concurrent loss of endoderm lineage specification was observed with Y-27632 treatment. Evidence would suggest that this effect is in part mediated through TGF-β and SMAD signaling as ROCK-inhibited cells displayed aberrant SMAD activation and did not return to a \u27ground\u27 state after the inhibition had been removed. Conclusions/Significance: Given this data and the fact that only a partial rescue of normal differentiation capacity occurred when ROCK inhibition was alleviated, the effect of ROCK inhibition on the differentiation capacity of pluripotent cell populations should be further examined to elucidate the role of the Rho-ROCK pathway in early cellular \u27fate\u27 decision making processes. © 2011 Krawetz et al

Towards the Final Fate of an Unstable Black String

Black strings, one class of higher dimensional analogues of black holes, were shown to be unstable to long wavelength perturbations by Gregory and Laflamme in 1992, via a linear analysis. We revisit the problem through numerical solution of the full equations of motion, and focus on trying to determine the end-state of a perturbed, unstable black string. Our preliminary results show that such a spacetime tends towards a solution resembling a sequence of spherical black holes connected by thin black strings, at least at intermediate times. However, our code fails then, primarily due to large gradients that develop in metric functions, as the coordinate system we use is not well adapted to the nature of the unfolding solution. We are thus unable to determine how close the solution we see is to the final end-state, though we do observe rich dynamical behavior of the system in the intermediate stages.Comment: 17 pages, 7 figure

Fitting parametric random effects models in very large data sets with application to VHA national data

<p>Abstract</p> <p>Background</p> <p>With the current focus on personalized medicine, patient/subject level inference is often of key interest in translational research. As a result, random effects models (REM) are becoming popular for patient level inference. However, for very large data sets that are characterized by large sample size, it can be difficult to fit REM using commonly available statistical software such as SAS since they require inordinate amounts of computer time and memory allocations beyond what are available preventing model convergence. For example, in a retrospective cohort study of over 800,000 Veterans with type 2 diabetes with longitudinal data over 5 years, fitting REM via generalized linear mixed modeling using currently available standard procedures in SAS (e.g. PROC GLIMMIX) was very difficult and same problems exist in Stata’s gllamm or R’s lme packages. Thus, this study proposes and assesses the performance of a meta regression approach and makes comparison with methods based on sampling of the full data.</p> <p>Data</p> <p>We use both simulated and real data from a national cohort of Veterans with type 2 diabetes (n=890,394) which was created by linking multiple patient and administrative files resulting in a cohort with longitudinal data collected over 5 years.</p> <p>Methods and results</p> <p>The outcome of interest was mean annual HbA1c measured over a 5 years period. Using this outcome, we compared parameter estimates from the proposed random effects meta regression (REMR) with estimates based on simple random sampling and VISN (Veterans Integrated Service Networks) based stratified sampling of the full data. Our results indicate that REMR provides parameter estimates that are less likely to be biased with tighter confidence intervals when the VISN level estimates are homogenous.</p> <p>Conclusion</p> <p>When the interest is to fit REM in repeated measures data with very large sample size, REMR can be used as a good alternative. It leads to reasonable inference for both Gaussian and non-Gaussian responses if parameter estimates are homogeneous across VISNs.</p

Correlation for Sessile Drop Evaporation Over a Wide Range of Drop Volatilities, Ambient Gases and Pressures

A correlation for the evaporation of sessile drops over a very broad range of conditions was developed based on measured evaporation rate data obtained for drops of acetone, methanol, and six hydrocarbons ranging from hexane to isooctane, evaporating in air, helium, argon, and krypton, over a range of ambient pressures from 96 kPa to 615 kPa. The experiments were designed to produce a large variation in the rates of diffusion and buoyancy-induced (natural) convection of the vapor phase amongst the experimental conditions. The correlation, which fits the measurements with an RMS relative error of 5.2%, is a simple equation involving conventional parameters for diffusive and convective transport and is applicable to conditions for which vapor transport limits the rate of evaporation. Application of the correlation requires knowledge of eight basic properties: the ambient pressure and temperature, the equilibrium vapor pressure of the evaporating component, the diffusion coefficient for the evaporating component in the ambient gas, the viscosity of the ambient gas, the radius of the sessile drop, and the molecular weights of the evaporating component and the ambient gas. The correlation is much easier to implement than a computational model based on the coupled conservation equations of mass, energy, and momentum for the two phases, and it offers a single mathematical expression that provides valuable insight into how the roles of diffusive and convective transport change with physical and geometrical parameters. The correlation can be a valuable tool to aid in the analyses of applications involving sessile drop evaporation and to support the validation of complex computational models. The range of experimental conditions resulted in a large variation in the rates of diffusive and naturally convective transport of the vapor. Over the range of experimental conditions, the liquid volatility, as indicated by the equilibrium vapor pressure, was varied by a factor of 16.7, the mass diffusivity by a factor of 52.2, the density difference ratio (the impetus for natural convection) by a factor of 3,557, and the drop radius by a factor of 22. In terms of the Rayleigh number, the experimental data covers a range from 5 to 361,000. Consequently, the correlation is applicable to a very broad range of conditions. To our knowledge these evaporation rate measurements of sessile drops in gases other than air and at pressures above one atmosphere are the first to be reported in the literature