Teacher Films: Examining Hollywood Representations of our Practice

What does it mean to teach and be taught? How have we come to know what schooling is? And, how can engagement with these pervasive, and oftentimes troubling representations of schooling, teaching, and students with our preservice teachers in/form their teacher identities? Taking Hollywood feature film as our inquiry into education, schooling, and social studies (teacher) education, this paper reflects upon the course Dangerous Minds, Dead Poets, and Democratic Education on the Silver Screen, a course the authors first developed as graduate students and have since offered variations of at their respective institutions. While course content has been relatively constant (using Dangerous Minds, Dead Poets Society, and Blackboard Jungle), additions of Clueless, School of Rock, Mean Girls, and Fist Fight have allowed for more intentional discussions of race, class, and gender, particularly as they relate to dominant tropes of representation for those in targeted identity groups

Fluctuation Induced Instabilities in Front Propagation up a Co-Moving Reaction Gradient in Two Dimensions

We study 2D fronts propagating up a co-moving reaction rate gradient in finite number reaction-diffusion systems. We show that in a 2D rectangular channel, planar solutions to the deterministic mean-field equation are stable with respect to deviations from planarity. We argue that planar fronts in the corresponding stochastic system, on the other hand, are unstable if the channel width exceeds a critical value. Furthermore, the velocity of the stochastic fronts is shown to depend on the channel width in a simple and interesting way, in contrast to fronts in the deterministic MFE. Thus, fluctuations alter the behavior of these fronts in an essential way. These affects are shown to be partially captured by introducing a density cutoff in the reaction rate. Some of the predictions of the cutoff mean-field approach are shown to be in quantitative accord with the stochastic results

The fixation probability of rare mutators in finite asexual populations

A mutator is an allele that increases the mutation rate throughout the genome by disrupting some aspect of DNA replication or repair. Mutators that increase the mutation rate by the order of 100 fold have been observed to spontaneously emerge and achieve high frequencies in natural populations and in long-term laboratory evolution experiments with \textit{E. coli}. In principle, the fixation of mutator alleles is limited by (i) competition with mutations in wild-type backgrounds, (ii) additional deleterious mutational load, and (iii) random genetic drift. Using a multiple locus model and employing both simulation and analytic methods, we investigate the effects of these three factors on the fixation probability $P_{fix}$ of an initially rare mutator as a function of population size $N$, beneficial and deleterious mutation rates, and the strength of mutations $s$. Our diffusion based approximation for $P_{fix}$ successfully captures effects (ii) and (iii) when selection is fast compared to mutation ($\mu/s \ll 1$). This enables us to predict the conditions under which mutators will be evolutionarily favored. Surprisingly, our simulations show that effect (i) is typically small for strong-effect mutators. Our results agree semi-quantitatively with existing laboratory evolution experiments and suggest future experimental directions.Comment: 46 pages, 8 figure

Objective visual field testing

The present research explored possibilities for objective visual field measurement devices and schemes and assessed their clinical application. A visual field measurement taken without cognitive patient response was sought. Instruments used were biomicroscopes and transilluminators, Eye-Trac, grain of wheat light board, infrared eye monitoring spectacles connected to a strip chart and audio-output device, and an EOG monitoring system. It was hypothesized that a discrete, involuntary eye movement toward a peripheral light occurred if the light was seen by the subject. No specific eye movement toward the stimulus was ever consistently detected. However, it was noted under certain conditions, identifiable refixation eye movements occurred when the peripheral stimulus was extinguished. Using grain of wheat bulbs, scotomas eight degrees in size or larger could be detected. This procedure could be clinically useful in the evaluation of visual fields in malingerers or other persons unable to be tested with present visual field testing procedures

Mutation Induced Extinction in Finite Populations: Lethal Mutagenesis and Lethal Isolation

Reproduction is inherently risky, in part because genomic replication can introduce new mutations that are usually deleterious toward fitness. This risk is especially severe for organisms whose genomes replicate “semi-conservatively,” e.g. viruses and bacteria, where no master copy of the genome is preserved. Lethal mutagenesis refers to extinction of populations due to an unbearably high mutation rate (U), and is important both theoretically and clinically, where drugs can extinguish pathogens by increasing their mutation rate. Previous theoretical models of lethal mutagenesis assume infinite population size (N). However, in addition to high U, small N can accelerate extinction by strengthening genetic drift and relaxing selection. Here, we examine how the time until extinction depends jointly on N and U. We first analytically compute the mean time until extinction (τ) in a simplistic model where all mutations are either lethal or neutral. The solution motivates the definition of two distinct regimes: a survival phase and an extinction phase, which differ dramatically in both how τ scales with N and in the coefficient of variation in time until extinction. Next, we perform stochastic population-genetics simulations on a realistic fitness landscape that both (i) features an epistatic distribution of fitness effects that agrees with experimental data on viruses and (ii) is based on the biophysics of protein folding. More specifically, we assume that mutations inflict fitness penalties proportional to the extent that they unfold proteins. We find that decreasing N can cause phase transition-like behavior from survival to extinction, which motivates the concept of “lethal isolation.” Furthermore, we find that lethal mutagenesis and lethal isolation interact synergistically, which may have clinical implications for treating infections. Broadly, we conclude that stably folded proteins are only possible in ecological settings that support sufficiently large populations.Chemistry and Chemical Biolog

Teaching About Global Debt In Social Studies Classrooms

The article offers guidelines in teaching high school students about global debt in their social studies class in the U.S. It outlines various ways on how to infuse discussions about global debt into social studies classrooms which include connecting the topic of global debt on a student\u27s personal finance, providing of instructional materials, and focusing on public policy dilemmas. The author suggests teaching students about global debt through student-centered pedagogy

The Challenge of Critical Pedagogy as a Social Studies Teacher Educator

This study examines the evolution of my understanding of critical pedagogy as I work alongside my students to co-construct the curriculum in our social studies teacher education course. As a critical pedagogue, I seek to challenge traditional structures of power and control in the classroom and problematize the ideas and discourses that define our ability to act (and be acted upon) within the context of higher education. I embrace Paulo Freire's vision of education as dialogue between students-teachers and teacher-student. Yet, my pedagogy is not enacted in a vacuum. My classes are bound within the institutional mandates of higher education and governed by state standards concerning teacher certification. Teachers and students are caught up in the context of schooling and the normative power that represents. My attempts to redefine asymmetrical classroom power relations are challenged by Foucault's argument that individuals assume responsibility for the constraints of power and become the principle of their own subjugation. Herein lies the crux of my dilemma as a critical social studies teacher educator: inhabiting the space between my commitment to Freirean critical pedagogy and my recognition of Foucauldian power relations. This study uses an autoethnographic lens to examine my evolution as a critical social studies teacher educator. I employ creative nonfiction and narrative vignettes to invite the reader to share in my experiences as a teacher educator and engage in a dialogue about the implications of the text. Teacher educators, teachers, and students grapple with issues of classroom power and control on a daily basis. This study opens a space for these readers to rethink their own pedagogical commitments and furthers the discussion of what it means to be a critical pedagogue. My understanding of authority and my conception of what it means to be a teacher educator continue to evolve as I work alongside students in a co-constructed social studies teacher education course. My discomfort with my institutional authority has given way to an acceptance of the authority that emerges from knowledge itself. I have come to recognize a difference between authoritarian pedagogy and pedagogical authority. These understandings continue to develop, for I am (and will always be) in my beginnings as a teacher educator

Policy issues and actors

Detention without trial can be a formidable government weapon against political opponents. In South Africa this weapon has been fashioned into a multiple warhead. There are currently seven security law detention provisions on the statute book, of which one is dormant but can be activated by the State President. Non security law detention, for example detention under drug laws, will not be discussed in this paper. While the seven detention laws are of varying severity and serve different purposes, they are best classified and explained under two main categories or groups - preventive detention and pre-trial detention

Applications of Sample Preparation Techniques in the Analysis of New Psychoactive Substances

The global rise of new psychoactive substances (NPSs) poses challenges for their analysis in biological matrices due to their complex chemistries and short market lifespan. A comparative study for the simultaneous extraction, separation, and detection of 19 NPSs was conducted. Six solid-phase extraction (SPE) methods and one supported liquid extraction method (SLE) were compared for the extraction of analytes from blood, serum, plasma, and urine. Comparisons of four derivatization agents were conducted, at four temperatures and two incubation times. Extraction methods were assessed by precision, sensitivity, and extraction efficiency. Derivatizing agents were assessed on their selectivity and sensitivity, and a three-way ANOVA was conducted to determine statistical significance. CSDAU SPE cartridges were shown to be the most efficient when extracting analytes from blood, serum, and plasma, whereas Xcel I cartridges performed the strongest when extracting analytes from urine. SPE extraction efficiencies, when utilizing the best-performing cartridges, ranged from 49 to 119%. SLE successfully extracted all analytes from all matrices (ranging from 22 to 120%). Pentafluoropropionic anhydride: ethyl acetate was the most successful derivatizing agent, allowing all analytes to be detected, with the highest peak area responses and more unique spectra. The optimum temperature for incubation was 37 °C, with no statistical difference found between the two incubation times

Application of a urine and hair validated LC-MS/MS method to determine the effect of hair colour on the incorporation of 25B-NBOMe, 25C-NBOMe and 25I-NBOMe into hair in the rat.

NBOMes are a group of new psychoactive substances derived from phenethylamines. Recreational abuse is thought to have begun in 2010 and they are commonly associated with the “club drug” scene. They are administered in liquid form or as blotters due to their high potency. An LC-MS/MS method was validated using SWGTOX parameters for the detection of 25B-, 25C- and 25I-NBOMe using 25B-NBOMe-D3 as internal standard for urine and hair. Calibration graphs with R2 values >0.99 were observed for urine and hair for concentrations ranging from 0.1 -100 ng/mL and 0.025-2.5 ng/mg respectively. Urine LODs ranged from 5-25 pg/mL and had an LOQ of 50 pg/mL. Hair LOD and LOQs ranged from 3-5 pg/mg and 6.25-12.5 pg/mg respectively. Intra and inter-day precision was <20% and accuracy was within ± 20% for both matrices. The method was shown to be selective for both exogenous and endogenous compounds. No matrix effects were observed for either matrix. LLE recovery ranged from 90-103% for urine samples and SPE recovery ranged from 80-107% for hair samples. Long-Evans rats (n=55) were administered 25B-, 25C- or 25I-NBOMe at doses ranging from 30-300 µg/kg over a period of 10 days. Rats were shaved prior to their first dose and re-shaved after the 10-day period. Hair was separated by colour (black: n=55 and white: n=55) and analysed using the validated LC-MS/MS method to assess the impact hair colour has on the incorporation of these drugs. All drugs were successfully detected in black hair. 25B-NBOMe from rats receiving the highest dose and 25C-NBOMe from rats receiving the medium and high doses were quantified in white hair. 25I-NBOMe was detected but fell below the limit of quantification. A dose-dependent concentration increase was observed in the black hair. All pooled urine samples tested positive for their expected NBOMes