Factors affecting insulin-stimulated in vitro glucose oxidation in rat epididymal adipocytes

Since Martin Rodbell published his collagenase method for isolating rat adipocytes from their stromal-vascular matrix in 1964, researchers have modified the procedure in an attempt to maximize results. These modifications are also purported to decrease the interlaboratory variability observed by researchers who utilize this procedure. Strict adherence to these modifications does not, however, necessarily result in robust, repeatable in vitro insulin-stimulated glucose oxidation. The purpose of this study was to optimize Rodbell\u27s procedure for measuring in vitro glucose oxidation in rat adipocytes, and to measure the effect of meal feeding on this process. Adipocytes from rats in 26 optimization experiments showed that the observed lack of insulin-stimulated glucose oxidation was not caused by reagents, environmental factors, or strain/size of animal. They also showed that the cause was likely related to an uncontrolled factor associated with the animals (ie, the pattern of food intake). Unlike adipocytes from rats in the optimization experiments, adipocytes from rats in the meal-feeding experiments showed a robust, reliable, expected increase (two to three-fold) in insulin-stimulated glucose oxidation. The average fold response in insulin-stimulated glucose oxidation was 3.5-fold. There was no significant difference in nmol glucose oxidized to CO2 between the three time points, but a trend toward decreasing nmol glucose oxidized in the presence of insulin over time was observed (p = 0.15). The adipocytes also showed a decrease in variability of absolute insulin stimulation over time (coefficient of variation decreased from 53% at 0 H-fasted to 29% at 20 H-fasted). In conclusion, meal feeding rats for approximately three weeks resulted in reproducible, robust insulin stimulation of glucose oxidation of adipocytes. This is the first study to investigate the short-term effects of two hour meal-feeding on adipocyte glucose oxidation

Replaying and Rediscovering The Octoroon

For over one hundred and fifty years, productions and adaptations of Irish playwright Dion Boucicault’s explosive 1859 melodrama, The Octoroon, have reflected differing and sometimes contentious meanings and messages about race and enslavement in a range of geographic locations and historical moments. Originally staged in New York in 1859, The Octoroon graphically portrayed the suicide of its white-appearing mixed-race heroine who had been auctioned into slavery. But in London, in 1861, Boucicault famously rewrote the ending, allowing the heroine to survive and be united with her white lover. Although theatre historians have known about Boucicault’s original adaption for over one hundred and fifty years, no extant script for that original “British” version has heretofore been discovered. Now, however, our recent archival discoveries reveal portions of that long-missing script. In addition, we have found that The Octoroon appeared on the colonial stages of Australia a full ten months before Boucicault changed the ending for London audiences. Our exploration of the performance history of The Octoroon in Australia further illustrates the potential shifting meanings of racial categories and representations of enslavement in nations whose colonial histories were built upon differing constructions of racist oppression, genocide, and slavery. Moreover, annotations in promptbooks from multiple nineteenth-century productions reveal ways stagings of The Octoroon have served as unique fluid—rather than stable—vehicles for depicting the transatlantic and colonial cultural attitudes that surrounded and tensions that emerged from antebellum representations of racialization, racial hybridity, interracial desire, and enslavement on both sides of the Atlantic and across British colonies in Australia

Review of Teacher Layoffs: Rethinking "Last Hired, First Fired" Policies

The reviewers credit the report for being straightforward and reasonable, but point out that the reforms it proposes are neither new nor unique and are very challenging to implement

Do Accountability Policies Push Teachers Out?

The impact of accountability on U.S. schools, for good or ill, is a subject of debate and research. The authors recently studied an aspect of accountability that had previously received little attention. They asked, do accountability reforms affect public schools\u27 ability to retain their teachers? By analyzing data from the Schools and Staffing Survey and the Teacher Followup Survey, they found strong (but unsurprising) evidence that accountability made teacher retention more difficult in low-performing schools; schools whose students scored low on high-stakes assessments had higher teacher turnover than those that scored higher; and schools that received sanctions because of their low performance had even higher turnover. The most helpful finding of the analysis was that even in schools subject to sanctions, higher teacher turnover was not inevitable. Schools that had better working conditions—and especially those that gave teachers greater classroom autonomy–were able to mitigate the negative effects of accountability sanctions. The authors conclude that holding teachers accountable for results must be paired with giving them control over the instruction that produces these results

Retaining Teachers: How Preparation Matters

A new study shows that teachers who receive less pedagogical training are more likely to leave teaching -- and that\u27s bad news for mathematics and science education

The Changing Face of Teaching

An analysis of nearly 30 years of data on the teaching force sheds new light on the makeup of the occupation—and on staffing priorities

What Are the Effects of Teacher Education and Preparation on Beginning Teacher Attrition?

This study addresses the question: Do the kinds and amounts of pre-service education and preparation that beginning teachers receive before they start teaching have any impact on whether they leave teaching? Authors Richard Ingersoll, Lisa Merrill, and Henry May examine a wide range of measures of teachers’ subject-matter education and pedagogical preparation. They compare different fields of teaching, with a particular focus on mathematics and science, using data from the National Center for Education Statistics’ nationally representative 2003-04 Schools and Staffing Survey and its supplement, the 2004-05 Teacher Follow-up Survey. The analyses show that beginning teachers widely varied in the pre-service education and preparation they received. In general, mathematics teachers and, especially, science teachers tended to have more subject-matter content education and more graduate-level education, and to have less pedagogical and methodological preparation than other teachers. The analyses also show that, after controlling for the background characteristics of teachers and their schools, some aspects of the education and preparation that beginning teachers received were significantly associated with their attrition, while others were not. Specifically, the type of college, degree, entry route or certificate mattered little. What did matter was the substance and content of new teachers’ pedagogical preparation. Those with more training in teaching methods and pedagogy—especially practice teaching, observation of other classroom teaching and feedback on their own teaching—were far less likely to leave teaching after their first year on the job

Environmental Injustice: How Treaties Undermine Human Rights Related to the Environment

Growing cries for action to effectively address the climate and other environmental crises hold important implications for the governance of cross-border investments. Policymakers and environmental advocates have often overlooked how provisions granted by states in international investment agreements (IIAs) have been used by investors to challenge government measures taken in the public interest to protect the environment and advance environmental justice. This 2019 paper, published in the Sciences Po Legal Review issue devoted to the climate crisis, explains how the investor-state dispute settlement (ISDS) mechanism, made available to investors in thousands of bilateral and multilateral trade and investment agreements, may influence the future of environmental justice. It revisits and builds upon discussions of how ISDS may chill legitimate and necessary regulation (or shift the costs thereof), elaborating upon theories of chill and providing examples of how ISDS has been used to challenge actions taken to address the climate crisis and protect threatened water resources. The paper also then explores implications for the environmental justice dimensions of environmental regulation, describing how ISDS can undermine democratic processes and stakeholders’ abilities to meaningfully participate in environmental decisionmaking and protect their rights. The paper concludes with recommendations on how states can address the systemic impact of ISDS on regulatory space over environmental and other matters of public interest