61 research outputs found
What can a studio approach to teaching tell us about the academic and social learning of middle school students? An exploration of student understanding of how making art supports their academic and social learning.
This study explores the types of social and academic learning typically overlooked in public school education. Art-based approaches to academic learning have been labeled as“fluff.” Education policymakers hold a biased view of the arts. When asked to consider art as a viable epistemology, cognition theorists have dismissed art as irrational. These biased views have contributed to the marginalization of the field of art education. The purpose of this study was to question this bias through an art-based studio approach to research. The goal was to explore how middle school students understand the role of visual arts in their own academic and social learning in this context. This qualitative study took place in a middle school in Northeast Massachusetts. Modifications of the research methods of Studio Thinking II (Hetland, Winner, Veneema, & Sheridan, 2013) and additional methods were used in the study. The student participants experienced “Eight Studio Habits of Mind” throughout eight sessions. These included: “Understanding Art worlds; Stretch and Explore; Reflect; Observe; Express; Envision; Engage and Persist, Develop Craft” (p.6). Throughout eight weeks seven classroom observations and two student interviews were conducted. During the eight sessions, students created art individually and in groups. To collect data, the researcher used the methods of pre-drawings and post-drawings (Chang, 2012, Einasdottir, Dockett, & Perry 2008), pre-questionnaires and post-questionnaires, (Song & Creegan- Quinquis, 2017), interviews, (Strauss & Corbin, 1990), art-making (Hetland, Veneema, Winner & Sheridan, 2013) and classroom observations (Behar,1996). To evaluate the data the researcher used grounded theory methods (Strauss & Corbin, 1990), which included the open and axial coding of interviews, drawings, and written responses. There were several findings. Findings showed significant changes in participants’ perceptions of themselves as artists. Findings included evidence of the negative effects of an outdated curriculum on students’ perceptions of the value of visual art in their lives. In addition, questionnaire and interview findings showed negative student perceptions regarding the ability of their existing curriculum to prepare them for a successful life after middle school. Student individual and collaborative drawings showed changes in artistic thinking and social engagement with their peers, art content, and larger societal issues
Multisensors detection of underwater magnetic signals : a wavelet packets application
Underwater magnetic signals are affected by a nonstationnary noise from different sources . In order to detect the distortion i n
the magnetic field caused by the displacement of a ferromagnetic mass we try to eliminate as much of the noise as possible b y
measuring the magnetic field with four sensors when the transient has been received by one of them . The differences between th e
signals from these sensors are calculated and processed using standard techniques such as the wavelet packets and the principa l
components analysis. We then show the performances and the limitations of the method .Les sources de bruit magnétique sont nombreuses et viennent perturber les signaux magnétiques sous-marins. Afin de détecter toute distorsion du champ magnétique terrestre, engendrée par le déplacement d'une masse ferromagnétique, nous utilisons quatre magnétomètres pour lesquels nous savons que le signal utile (s'il existe) ne peut être vu que par l'un d'entre eux. En combinant les différences inter-capteurs et en nous appuyant sur l'analyse de la transformée par paquets d'ondelettes associée à une analyse en composantes principales nous montrons les performances de la méthode de détection ainsi que ses limitations
A time-frequency approach to blind deconvolution in multipath underwater channels
Blind deconvolution is presented in the underwater acoustic channel context, by time-frequency processing. The acoustic propagation environment was modelled as a multipath propagation channel. For noiseless simulated data, source signature estimation was performed by a model-based method. The channel estimate was obtained via a time-frequency formulation of the conventional matched-filter. Simulations used a ray-tracing physical model, initiated with at-sea recorded environmental data, in order to produce realistic underwater channel conditions. The quality of the estimates was 0.793 for the source signal, and close to I for the resolved amplitudes and time-delays of the impulse response. Time-frequency processing has proved to overcome the typical ill-conditioning of single sensor deterministic deconvolution techniques
Comparison of classification methods : An application in underwater ferromagnetic object identification
The time-frequency analysis of magnetic signals, generated by ferromagnetic objects, is used to extract a robust discriminan t
parameter set for their classification . After the feature selection phase, an extensive study is performed in order to validate th e
most appropriate classifier structure, in terms of the correct classification rate and the generalization ability . The K-NN Famil y
and the neural networks based classifiers are the candidates we are working with . The Fuzzy-logic contribution and the neura l
networks capabilities are highlighted by means of a large number of test vectors and for a significative S/N ratio range.L'analyse temps-fréquence des signaux magnétiques, générés par des objets ferromagnétiques sous-marins, est utilisée afin de trouver un ensemble de paramètres discriminants pour leur classification. Après l'étape de sélection de caractéristiques, une étude étendue est menée pour comparer différentes structures de classifieurs, en fonction du taux moyen de bonne classification et de la capacité de généralisation. Les vertus de la logique floue, intégrée dans les classifieurs de la famille des K plus proches voisins (K-NN), et des classifieurs à base de réseaux de neurones sont mises en évidence au moyen d'un grand nombre de vecteurs de test et à une plage significative de variation pour le rapport S/B
Application d'opérateurs de fusion floue à la classification automatique de cibles réalisée par un radar polarimétrique
L'article décrit l'application de quelques opérateurs de fusion floue pour la classification automatique de profils de distance mesurés par un radar polarimétrique. L'acquisition des signatures radar réelles est réalisée dans la chambre anéchoïde de l'ENSIETA, pour 5 modèles d'avions réduits à l'échelle et 3 combinaisons de polarisation. L'analyse des résultats en classification obtenus au travers des intégrales de Sugeno et de Choquet, ainsi que de la théorie des possibilités, permet de conclure sur les opérateurs de fusion floue les mieux adaptés dans le contexte de l'application visée
Application des moments d'ordre supérieur à la focalisation des images ISAR
L'écart entre le modèle cinématique ISAR et le mouvement réel de la cible a comme conséquence la dé-focalisation de l'image acquise. L'article aborde le cas peu traité de la cible très mobile (loi de mouvement d'ordre élevé) et utilise une approche basée sur la fonction d'ambiguïté d'ordre supérieur afin d'estimer les trajets des points brillants. La compensation est effectuée en deux étapes, visant l'élimination des résidus de translation et des non-uniformités du mouvement de rotation
Modélisation des cibles détectées par un radar de surveillance maritime à haute résolution
- Afin d'optimiser les performances des radars à haute résolution pour la détection à la surface de la mer il est nécessaire de développer des modèles adéquats aussi bien pour les cibles navales que pour le fouillis de mer. Alors que ce dernier fait l'objet de nombreuses études, les modèles des cibles utilisés sont toujours ceux développés par Swerling. Le modèle proposé dans l'article intègre les effets de la haute résolution en distance assurée par le radar et de la visibilité géométrique discontinue, qui apparaît surtout dans le cas des petites cibles
Technique neuronale pour la détection CFAC optimale dans du fouillis de mer non-Gaussien
- Un nouveau processeur radar CFAR (Constant False Alarm Rate) pour la détection optimale des cibles navales est proposé dans l'article. Il est basé sur l'utilisation d'un réseau de neurones pour approximer de façon implicite, par apprentissage, les densités de probabilité multidimensionnelles correspondant au fouillis et au signal écho utile. La règle de décision utilisée est équivalente au test du maximum du rapport de vraisemblance généralisé. Des méthodes pour le calcul du seuil de détection et pour assurer son invariance par rapport au rapport S/B et aux paramètres du fouillis sont également présentées
Mineral trioxyde aggregate versus calcium hydroxide in apexification of non vital immature teeth: Study protocol for a randomized controlled trial
<p>Abstract</p> <p>Background</p> <p>Pulp necrosis is one of the main complications of dental trauma. When it happens on an immature tooth, pulp necrosis implies a lack of root maturation and apical closure. A therapy called apexification is required to induce the formation of a calcified apical barrier allowing a permanent and hermetic root filling. The aim of this prospective randomized clinical trial is to compare Mineral Trioxide Aggregate(MTA)with Calcium Hydroxide(CH)as materials used to induce root-end closure in necrotic permanent immature incisors.</p> <p>Methods/Design</p> <p>This study, promoted by AP-HP, was approved by the ethics committee(CPP Paris Ile de France IV). 34 children aged from 6 to 18 years and presenting a non-vital permanent incisor are selected. Prior to treatment, an appropriate written consent has to be obtained from both parents and from children. Patients are then randomly assigned to either the MTA(experimental)or CH(control)groups. Recalls are performed after 3, 6 and 12 months to determine the presence or absence of a calcified apical barrier through the use of clinical and radiographic exams. Additional criteria such as clinical symptoms, apical radiolucencies, periapical index(PAI)are also noted.</p> <p>Trial registration</p> <p>ClinicalTrials.gov no. <a href="http://www.clinicaltrials.gov/ct2/show/NCT00472173">NCT00472173</a> (First inclusion: May 10, 2007; Last inclusion: April 23, 2009; study completed: April 15, 2010)</p
The gut microbiota in multiple sclerosis varies with disease activity
BACKGROUND: Multiple sclerosis is a chronic immune-mediated disease of the brain and spinal cord resulting in physical and cognitive impairment in young adults. It is hypothesized that a disrupted bacterial and viral gut microbiota is a part of the pathogenesis mediating disease impact through an altered gut microbiota-brain axis. The aim of this study is to explore the characteristics of gut microbiota in multiple sclerosis and to associate it with disease variables, as the etiology of the disease remains only partially known. METHODS: Here, in a case-control setting involving 148 Danish cases with multiple sclerosis and 148 matched healthy control subjects, we performed shotgun sequencing of fecal microbial DNA and associated bacterial and viral microbiota findings with plasma cytokines, blood cell gene expression profiles, and disease activity. RESULTS: We found 61 bacterial species that were differentially abundant when comparing all multiple sclerosis cases with healthy controls, among which 31 species were enriched in cases. A cluster of inflammation markers composed of blood leukocytes, CRP, and blood cell gene expression of IL17A and IL6 was positively associated with a cluster of multiple sclerosis-related species. Bacterial species that were more abundant in cases with disease-active treatment-naïve multiple sclerosis were positively linked to a group of plasma cytokines including IL-22, IL-17A, IFN-β, IL-33, and TNF-α. The bacterial species richness of treatment-naïve multiple sclerosis cases was associated with number of relapses over a follow-up period of 2 years. However, in non-disease-active cases, we identified two bacterial species, Faecalibacterium prausnitzii and Gordonibacter urolithinfaciens, whose absolute abundance was enriched. These bacteria are known to produce anti-inflammatory metabolites including butyrate and urolithin. In addition, cases with multiple sclerosis had a higher viral species diversity and a higher abundance of Caudovirales bacteriophages. CONCLUSIONS: Considerable aberrations are present in the gut microbiota of patients with multiple sclerosis that are directly associated with blood biomarkers of inflammation, and in treatment-naïve cases bacterial richness is positively associated with disease activity. Yet, the finding of two symbiotic bacterial species in non-disease-active cases that produce favorable immune-modulating compounds provides a rationale for testing these bacteria as adjunct therapeutics in future clinical trials
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