Blinded by Whiteness: Middle-Class White Teachers’ Explorations of Identity and Deficit Discourse at the Intersection of Race, Class, and Perceived Ability

A legacy of placing children of color and poverty at the center of the “problem” of race and class in education has left us in a holding pattern marked by a prevailing deficit discourse and problematizing of students. Scholars agree that the predominantly white, middle class, female teaching force who occupy US public school classrooms embody and perpetuate these inequitable educational practices endemic within this system. In this study, a small population of White, middle class teachers--including the researcher--organized within a Professional Learning Community (PLC) explored identity and deficit discourse at the intersection of race, class, and perceived ability. Grounded in Feminist Standpoint Theory, Social Identity Theory, Critical Whiteness Theory, and Transformative Learning Theory and employing a critical-ideological stance, the investigation sought to understand how participation in a professional learning group impacted teachers’ perceptions of themselves and their students. To that end, meeting transcripts, interviews with PLC participants, artifacts, reflective journals, memos, and classroom observations provided data that was examined through a heuristic phenomenological lens. Research findings indicate that participation in a PLC focused on identity and deficit discourse in the classroom results in White, middle-class teachers’ increased awareness of privilege and power disparities between teachers and students as well as increased sensitivity to the mindsets that inform their discourse to and about students. Further, evidence suggests that PLCs can create safe spaces which foster deep professional relationships, vulnerability, and sustained self- and group-reflection are appropriate and effective sites for engaging identity work. Implications of these findings at all levels of the educational system--classrooms, school districts, and broader policy issues--are presented with an eye toward affecting sustainable change. Finally, study limitations and opportunities for further research are considered and framed

Development of Scent Detection and Categorization Algorithm Using Gas Chromatography and Machine Learning

There are many looking to connect human senses to quantifiable data. Scents are categorized by their descriptions into scent families. These include citrus, floral, and woody. Similar descriptors designate similar families, while different descriptors correlate with different families. Dravnieks compiled an Atlas of chemical descriptors [1]. Such descriptors are cinnamon, fruity, and cadaverous. By analyzing the applicability of these descriptors, the chemicals will be sorted into their scent families. Gas chromatography generates sample-specific signals of voltage over time. Chromatograms of known scents will serve as a basis for a convolutional neural network. This algorithm will be trained on these signals and tested with unknown scents to categorize scents with no human participation. We seek to generate verbal descriptions of scent through machine learning analysis of GC signals

Regionalisation of human ES cell derived neural precursors

The derivation of region-specific neural cells from human embryonic stem cells holds great promise for future cell replacement strategies of neurodegenerative diseases. However, the possibility to recreate the diversity of the mature CNS with its numerous types of neurons displaying distinct region-specific transcription factor expression profiles in vitro using defined morphogens seems limited. Therefore this study sought to investigate whether primary cells from different regions of the developing rodent brain - which themselves are known to be regionally specified - can influence the regional identity of human ES cell-derived neural stem cells (hESNSCs). After establishing the regional gene expression profile of the hESNSCs under standard culture conditions in vitro, the cells were exposed to paradigmatic co-culture settings. To that end cells from forebrain, midbrain, hindbrain/cerebellum and spinal cord of embryonic and P0 mice as well as hippocampal and cerebellar slices of 9-day-old rats were used. To analyse the gene expression of co-cultured human cells human-specific real time RT-PCR primers were designed and implemented. Surprisingly, neither co-culturing with nor transplantation onto or even in vivo transplantation into different brain regions induced significant changes in region-specific gene expression in the hESNSCs. As it is known that the developmental potential of ES cells can be in part ascribed to their dynamic epigenetic state it was subsequently tested whether subjecting the hESNSCs to DNA demethylation and histone hyperacetylation would alter their developmental competence. Remarkably, even modifying the epigenetic state did not suffice to increase the responsiveness of hESNSCs to primary cell derived cues. However, administration of VPA and AzaC seemed capable of intensifying the effect of defined morphogens such as retinoic acid and BMP4 to posteriorize and dorsalize the hESNSCs, respectively. These observations suggest that hESNSCs retain a responsiveness to high levels of single morphogens but are not easily amenable to regional specification by tissue derived environmental cues even after DNA demethylation and histone hyperacetylation

Effects of margin-parallel shortening and density contrasts on back-arc extension during subduction: Experimental insights and possible application to Anatolia

International audienceSo as to investigate the parameters influencing subduction and back-arc extension, we have done three series of laboratory experiments (32 in all) on physical models. Each model consisted of adjacent oceanic and continental plates, floating on an asthenosphere. In experiments of Series A, a wide rigid piston, moving horizontally, controlled the rate of convergence of the oceanic and continental plates, whereas, in Series B or C, a wide or narrow piston produced lateral compression, parallel to the continent-ocean boundary (COB) and perpendicular to the subduction direction. The parameters that we tested were (1) the velocity of plate convergence (Series A), (2) the width of the compressing piston (Series B and C), and (3) the density ratio between oceanic and continental plates (Series B and C). This density ratio was a key factor. For a ratio of 1.4, the amount of extension in the continental plate increased regularly throughout time; for a ratio of 1.3, the extension remained small, until the piston stopped moving laterally; and for a ratio of 1.1, there was little or no extension. The width of the compressing piston had a smaller effect, although a narrow piston provided more space, into which the continental plate could extend. One possible application of our models is to Anatolia. Despite similar geological settings, the areas north of the Hellenic and Cyprus subduction zones differ, in that extension is large in the former and much smaller in the latter. We suggest that one of the main driving forces for Aegean extension may have been a high density ratio between subducting oceanic lithosphere and a Hellenic-Balkanic upper plate

Modelización analógica de la deformación en las zonas de compresión y subducción

Cette thèse présente les résultats et conclusions issues d une série de modèles analogiques de systèmes de compressif à différentes échelles : Les expériences réalisées à l échelle crustale montrent que la symétrie de structures compressives, de type plis et chevauchements avec 3 niveaux de décollement, est fortement dépendante de la vitesse de sédimentation. Les résultats ont été appliqués au Subandin Bolivien. Les expériences réalisées à l échelle lithosphérique simulent la subduction et l extension arrière-arc dans un système subissant une compression parallèle à la marge continent-océan (COB). Ces modèles démontrent que la différence de densité entre les plaques continentales et océaniques est le paramètre clé pour expliquer l'extension arrière-arc: plus petite est la différence de densité, plus faible est l'extension produite. Les résultats ont été appliqués al Anatolie. En n, ces modèles ont été utilisés pour tester la reproductibilité et les limites de la modélisation analogique.This thesis presents the results and conclusions from a series of analogue modelling of deformation in compressive and subduction zones (crustal scale and lithospheric scale) : The experiments carried out at the crustal scale show that the symmetry of compressive structures, folds and trust belts with 3 levels of décollement is strongly dependent on the rate of sedimentation. The results were applied to the Subandin Bolivian. The experiments carried out at the lithospheric scale simulate subduction and back-arc extension in a system under compression parallel to the continent - ocean margin (COB). These models show that the density ratio between the continental and oceanic plates is the key factor to explain the back-arc extension: as smaller the difference in density is, less extension occurred. The results were applied to Anatolia. Finally, these models were used to test the reproducibility and limits for analog modeling.RENNES1-Bibl. électronique (352382106) / SudocSudocFranceF

A murine specific expansion of the Rhox cluster involved in embryonic stem cell biology is under natural selection

BACKGROUND: The rodent specific reproductive homeobox (Rhox) gene cluster on the X chromosome has been reported to contain twelve homeobox-containing genes, Rhox1-12. RESULTS: We have identified a 40 kb genomic region within the Rhox cluster that is duplicated eight times in tandem resulting in the presence of eight paralogues of Rhox2 and Rhox3 and seven paralogues of Rhox4. Transcripts have been identified for the majority of these paralogues and all but three are predicted to produce full-length proteins with functional potential. We predict that there are a total of thirty-two Rhox genes at this genomic location, making it the most gene-rich homoeobox cluster identified in any species. From the 95% sequence similarity between the eight duplicated genomic regions and the synonymous substitution rate of the Rhox2, 3 and 4 paralogues we predict that the duplications occurred after divergence of mouse and rat and represent the youngest homoeobox cluster identified to date. Molecular evolutionary analysis reveals that this cluster is an actively evolving region with Rhox2 and 4 paralogues under diversifying selection and Rhox3 evolving neutrally. The biological importance of this duplication is emphasised by the identification of an important role for Rhox2 and Rhox4 in regulating the initial stages of embryonic stem (ES) cell differentiation. CONCLUSION: The gene rich Rhox cluster provides the mouse with significant biological novelty that we predict could provide a substrate for speciation. Moreover, this unique cluster may explain species differences in ES cell derivation and maintenance between mouse, rat and human

Modelización analógica de la deformación en las zonas de compresión y subducción

[spa] Esta tesis presenta una serie de modelos analógicos en sistemas compresivos a diferentes escalas. Los de escala cortical simulan estructuras compresivas de antepais y los de escala litosférica simulan la deformación de la placa continental en zonas de subducción. Los de escala cortical se han realizado para comprobar la evolución de una única estructura perteneciente a un sistema de pliegues y cabalgamientos. Esta estructura está sometida a sedimentación sincinemática durante la compresión y tiene dos niveles de despegue precinematicos. La estructura resultante es asimétrica en el caso de poca sedimentación y poco acortamiento, y su simetría aumenta cuando la sedimentación sincinemática y el acortamiento aumentan. Los resultados se han aplicado al Subandino boliviano. Los de escala litosférica se han realizado para investigar los parámetros que influencian la subducción y la extensión trasarco. Cada modelo consiste en dos placas adyacentes compuestas de arena y silicona, que simulan una placa continental y otra oceánica. Estas placas están flotando sobre miel que simula la astenósfera. Los parámetros estudiados son: (1) la velocidad de convergencia, (2) el tamaño del pistón y (3) la diferencia de densidades entre las placas continental y oceánica. Esta diferencia de densidades es el parámetro clave para explicar la extensión trasarco, y cuanto menor es esta diferencia menor es la extensión que se produce. El caso natural donde se han aplicado estos modelos es Anatolia. Finalmente estos modelos anteriores han sido utilizados para analizar la reproducibilidad y las limitaciones de la modelización analógica. Los parámetros que pueden influenciar los resultados son: (i) la heterogeneidad de los materiales, (ii) la técnica de construcción del modelo, (iii) los posibles problemas que pueden aparecer cuando el experimento está en marcha, (iv) la heterogeneidad natural de la deformación, y (v) la localización de la observación. Los resultados muestran que no todos los modelos tienen la misma reproducibilidad, los experimentos a escala cortical permiten análisis cuantitativos mientras que los de escala litosférica solo permiten análisis cualitativos