Is first-gen an identity? How first-generation college students make meaning of institutional and familial constructs of self

Institutions increasingly use first-generation categorizations to provide support to students. In this study, we sought to understand how students make meaning of their first-generation status by conducting a series of focus groups with 54 participants. Our findings reveal that students saw first-generation status as an organizational and familial identity rather than a social identities. This status was connected to alterity and social distance that was most salient in comparison to continuing-generation peers. Our recommendations include re-examining the role of first- generation specific programming on campus, creating opportunities for meaning-making, supporting students within changing family dynamics, and exploring the interaction between first-generation status and other marginalized identities

Noisy image restoration using Markov random field in a multiresolution scheme

The restoration methods involving Markov random fields with line process for the discontinuities are known to give good results in edge preserving image restoration . The Markov model is developped on the image decomposed at several resolutions using a wavelet transform . A deterministic relaxation algorithm (GNC) performs the minimization of the non convex criterion . Several multiresolution algorithms are developped and results are compared with those in monoresolution . These multiresolution algorithms provide better results with less computation time .La modélisation de l'image et de ses discontinuités par champ markovien a pour objectif dans la restauration d'image de préserver les contours. Dans cet article l'image est d'abord décomposée à différents niveaux de résolutions par transformée en ondelettes. Un champ markovien est défini pour chaque résolution et l'image est restaurée itérativement en fonction des résolutions croissantes. Cet algorithme est analysé comparativement à un algorithme monorésolution et montre son efficacité en terme de réduction de temps de calcul et qualité de l'image restauré

Basement control on dyke distribution in Large Igneous Provinces: Case study of the Karoo triple junction.

Continental flood basalts consist of vast quantities of lava, sills and giant dyke swarms that are associated with continental break-up. The commonly radiating geometry of dyke swarms in these provinces is generally interpreted as the result of the stress regime that affected the lithosphere during the initial stage of continental break-up or as the result of plume impact. On the other hand, structures in the basement may also control dyke orientations, though such control has not previously been documented. In order to test the role of pre-dyke structures, we investigated four major putative Karoo-aged dyke swarms that taken together represent a giant radiating dyke swarm (the so-called "triple-junction") ascribed to the Jurassic Karoo continental flood basalt (> 3x10 6 km2; southern Africa). One of the best tests to discriminate between neoformed and inherited dyke orientation is to detect Precambrian dykes in the Jurassic swarms. Accordingly, we efficiently distinguished between Jurassic and Precambrian dykes using abbreviated low resolution, 40Ar/39Ar incremental heating schedules. Save-Limpopo dyke swarm samples (n = 19) yield either apparent Proterozoic (728-1683 Ma) or Mesozoic (131-179 Ma) integrated ages; the Olifants River swarm (n = 20) includes only Proterozoic (851-1731 Ma) and Archaean (2470-2872 Ma) dykes. The single age obtained on one N-S striking dyke (1464 Ma) suggests that the Lebombo dyke swarm includes Proterozoic dykes in the basement as well. These dates demonstrate the existence of pre-Karoo dykes in these swarms as previously hypothesized without supporting age data.In addition, aeromagnetic and air-photo interpretations indicate that: (1) dyke emplacement was largely controlled by major discontinuities such as the Zimbabwe and Kaapvaal craton boundaries, the orientation of the Limpopo mobile belt, and other pre-dyke structures including shear zones and (2) considering its polygenetic, pre-Mesozoic origin, the Olif ants River dyke swarm cannot be considered part of the Karoo magmatic event.This study, along with previous results obtained on the Okavango dyke swarm, shows that the apparent "triple junction" formed by radiating dyke swarms is not a Jurassic structure; rather, it reflects weakened lithospheric pathways that have controlled dyke orientations over hundreds of millions of years. One consequence is that the "triple-junction" geometry can no longer be unambiguously used as a mantle plume marker as previously proposed, although it does not preclude the possible existence of a mantle plume. More generally, we suggest that most Phanerozoic dyke swarms (including triple junctions) related to continental flood basalts were probably controlled in part by pre-existing lithospheric discontinuities

High efficiency image restoration using mirror images and adaptive Kalman filtering

The purpose of this paper is image restoration by means of fast parallel Kalman filtering . This algorithm was introduced by Biemond et al. in 1983 [13] for image restoration . The problem is the appearance of ringing in the restored image. It results front the implicit assumption of rows periodicity, when FFT is applied on the image rows. Since left and right boundaries values are différent, discontinuity points appear . In order to achieve boundary condition suitable for the ID horizontal FFT processing, we use in the algorithm a mirror image . We first give the description of this mirror image, and then we exploit in the algorithm its horizontal properties of boundaries continuity and symmetry. Then, an adaptive Kalman filtering is introduced to avoid non consistency of the Kalman gains factors on some frequencies, and to reduce the remaining ringing. Finally results are shown for some images and PSF .Notre propos est la restauration d'image dégradée par un flou ou un bougé, additionné d'un bruit . La méthode proposée est dérivée de l'algorithme de filtrage récursif introduit par Biemond en 1983 [13] qui offre l'avantage d'être plus rapide que d'autres méthodes de restauration d'image, et de réaliser une déconvolution significative . L'écriture vectorielle du modèle AR 2D de l'image et de la dégradation fait apparaître des matrices de Toeplitz . Celles-ci approchées par des matrices circulantes, sont facilement diagonalisées par FFT. Cette diagonalisation permet de transformer le système 2D de taille N x N, en N systèmes 1D disjoints de taille N : l'application de N FFT sur les lignes permet d'obtenir N filtres de Kalman disjoints sur les colonnes . L'utilisation de la FFT, qui suppose la périodicité du signal traité, fait apparaître une discontinuité entre les bords droit et gauche de l'image . Cette discontinuité du signal crée des fréquences parasites qui se traduisent sur l'image restaurée, par des bandes verticales blanches et noires . Afin d'éliminer ces rayures, nous proposons d'utiliser dans cet algorithme une image miroir construite à partir de l'image originale : l'image à traiter possède alors des propriétés de continuité et de symétrie que nous exploitons . Enfin, nous développons un filtre adaptatif de Kalman appliqué au signal 1D à restaurer, afin de réduire la dynamique des gains du filtre de certains de ces signaux . Des résultats sont présentés sur des images artificiellement rendues floues ou bougées

<i>InSpectra</i> - A platform for identifying emerging chemical threats

Non-target analysis (NTA) employing high-resolution mass spectrometry (HRMS) coupled with liquid chromatography is increasingly being used to identify chemicals of biological relevance. HRMS datasets are large and complex making the identification of potentially relevant chemicals extremely challenging. As they are recorded in vendor-specific formats, interpreting them is often reliant on vendor-specific software that may not accommodate advancements in data processing. Here we present InSpectra, a vendor independent automated platform for the systematic detection of newly identified emerging chemical threats. InSpectra is web-based, open-source/access and modular providing highly flexible and extensible NTA and suspect screening workflows. As a cloud-based platform, InSpectra exploits parallel computing and big data archiving capabilities with a focus for sharing and community curation of HRMS data. InSpectra offers a reproducible and transparent approach for the identification, tracking and prioritisation of emerging chemical threats

Traitement du signal audio-visuel et visiophone personne libre

Les informations visuelles et acoustiques sont au coeur de la (télé)communication entre les personnes. Le visage est la principale source d'information. Des techniques de détection du mouvement et de la teinte de la peau délimitent des régions d'intérêt où peuvent se trouver des visages. Un réseau de neurones détecte le visage et fournit la position et l'échelle du visage. Le visage repéré est suivi, en temps réel, par une caméra motorisée et par une antenne acoustique qui génère un lobe orientable. La prise de vue et la prise de son sont ainsi centrées en permanence sur l'utilisateur qui est libre de se déplacer et libre de tout équipement spécifique. Le traitement du signal audio-visuel sont intégrées à LISTEN, démonstrateur du visiophone "personne libre"

Conditional variable importance for random forests

Random forests are becoming increasingly popular in many scientific fields because they can cope with ``small n large p'' problems, complex interactions and even highly correlated predictor variables. Their variable importance measures have recently been suggested as screening tools for, e.g., gene expression studies. However, these variable importance measures show a bias towards correlated predictor variables. We identify two mechanisms responsible for this finding: (i) A preference for the selection of correlated predictors in the tree building process and (ii) an additional advantage for correlated predictor variables induced by the unconditional permutation scheme that is employed in the computation of the variable importance measure. Based on these considerations we develop a new, conditional permutation scheme for the computation of the variable importance measure. The resulting conditional variable importance is shown to reflect the true impact of each predictor variable more reliably than the original marginal approach

Seismic and geochemical evidence for large-scale mantle upwelling beneath the eastern Atlantic and western and central Europe

Seismic tomography and the isotope geochemistry of Cenozoic volcanic rocks suggest the existence of a large, sheet-like region of upwelling in the upper mantle which extends from the eastern Atlantic Ocean to central Europe and the western Mediterranean. A belt of extension and rifting in the latter two areas appears to lie above the intersection of the centre of the upwelling region with the base of the lithosphere. Lead, strontium and neodymium isotope data for all three regions converge on a restricted composition, inferred to be that of the upwelling mantle