731 research outputs found
Attentional networks in developmental dyscalculia
<p>Abstract</p> <p>Background</p> <p>Very little is known about attention deficits in developmental dyscalculia, hence, this study was designed to provide the missing information. We examined attention abilities of participants suffering from developmental dyscalculia using the attention networks test - interactions. This test was designed to examine three different attention networks--executive function, orienting and alerting--and the interactions between them.</p> <p>Methods</p> <p>Fourteen university students that were diagnosed as suffering from developmental dyscalculia--intelligence and reading abilities in the normal range and no indication of attention-deficit hyperactivity disorder--and 14 matched controls were tested using the attention networks test - interactions. All participants were given preliminary tests to measure mathematical abilities, reading, attention and intelligence.</p> <p>Results</p> <p>The results revealed deficits in the alerting network--a larger alerting effect--and in the executive function networks--a larger congruity effect in developmental dyscalculia participants. The interaction between the alerting and executive function networks was also modulated by group. In addition, developmental dyscalculia participants were slower to respond in the non-cued conditions.</p> <p>Conclusions</p> <p>These results imply specific attentional deficits in pure developmental dyscalculia. Namely, those with developmental dyscalculia seem to be deficient in the executive function and alertness networks. They suffer from difficulty in recruiting attention, in addition to the deficits in numerical processing.</p
Acute kidney injury in critically ill newborns: What do we know? What do we need to learn?
Outcomes in critically ill neonates have improved over the past three decades, yet high residual mortality and morbidity rates exist. Acute kidney injury (AKI) is not just an innocent by-stander in the critically ill patient. Research on incidence and outcomes of AKI in the critically ill neonatal population is scarce. The objective of this publication is to (a) review original articles on the short- and long-term outcomes after neonatal AKI, (b) highlight key articles on adults and children with AKI in order to demonstrate how such insights might be applied to neonates, and (c) suggest clinical research studies to fill the gaps in our understanding of neonatal AKI. To date, observational studies suggest high rates of AKI and poor outcomes in critically ill neonates. Neonates with AKI are at risk of developing chronic kidney disease and hypertension. Large prospective studies are needed to test definitions and to better understand risk factors, incidence, independent outcomes, and mechanisms that lead to poor short- and long-term outcomes. Early biomarkers of AKI need to be explored in critically ill neonates. Infants with AKI need to be followed for sequelae after AKI
Du Couplage Ultra-Fort Lumière-Matière: Nouvelle Ingénierie de Métamatériaux Térahertz
Sub-wavelength patterning of one or several materials can give rise to “metamaterials”, with artificial electromagnetic properties. This work is focused on the design and realization of THz metamaterials, exploiting plasmonic cavity engineering and many-body effects in a dense electron gas. In the first part of this manuscript, many-body effects are investigated through the optical response of an electron gas in a semiconductor layer. The electron gas displays a cooperative response to an incident electromagnetic field: its absorption spectrum shows a unique sharp resonance, centred at an energy that depends on the electronic density and on the confinement. A model is presented that describes infrared absorption of thin doped semiconductor layers as well as intersubband absorption in a quantum well. When a highly doped semiconductor layer is inserted in a metallic microcavity, the so called “ultra-strong” coupling regime is achieved between the electronic many-body excitation and the cavity fundamental optical mode. Through an optimization of the cavity geometry, I demonstrate a record value of the relative coupling strength at room temperature. The ultra-strong coupling regime is then used for two different applications: a metamaterial with an artificial photonic reflectivity band and a cavity with an extremely high effective index. Those cavities are then used to realize an incandescent THz source, operating at room temperature.La structuration artificielle d’un matériau par des motifs sub-longueurs d’onde peut donner lieu à des « métamatériaux », avec des propriétés électromagnétiques qu’on ne retrouve pas dans un milieu naturel. Mon travail de thèse concerne la conception et la réalisation de métamatériaux THz, basés à la fois sur l’ingénierie de cavités plasmoniques et sur les propriétés multi-corps d’un gaz d’électrons dans un semiconducteur. Dans la première partie de la thèse, j’ai étudié ces propriétés multi-corps à travers la réponse optique du gaz d’électrons. J’ai démontré qu’il répond de façon coopérative à un champ électromagnétique incident : son spectre d’absorption présente une unique résonance étroite, à une énergie qui dépend à la fois de l’éventuel confinement et de la densité électronique. J’ai démontré qu’un même formalisme peut être utilisé pour décrire l’absorption infrarouge dans des couches minces dopées et l’absorption intersousbande dans un puits quantique. En insérant la couche semiconductrice dans une cavité métallique, un régime de couplage ultra-fort entre l’excitation électronique et le mode fondamental de la cavité peut être atteint. Grâce à l’optimisation de la cavité, j’ai pu démontrer une valeur record de l’énergie de couplage relative à température ambiante. Le couplage ultra-fort a été ensuite utilisé pour deux applications différentes : la démonstration d’un métamatériau possédant une bande interdite artificielle pour les photons et la réalisation de cavités d’indice optique effectif particulièrement élevé. Ces cavités m’ont permis de concevoir et réaliser une source incandescente de lumière THz, fonctionnant à température ambiante
Multiplierz: An Extensible API Based Desktop Environment for Proteomics Data Analysis
BACKGROUND. Efficient analysis of results from mass spectrometry-based proteomics experiments requires access to disparate data types, including native mass spectrometry files, output from algorithms that assign peptide sequence to MS/MS spectra, and annotation for proteins and pathways from various database sources. Moreover, proteomics technologies and experimental methods are not yet standardized; hence a high degree of flexibility is necessary for efficient support of high- and low-throughput data analytic tasks. Development of a desktop environment that is sufficiently robust for deployment in data analytic pipelines, and simultaneously supports customization for programmers and non-programmers alike, has proven to be a significant challenge. RESULTS. We describe multiplierz, a flexible and open-source desktop environment for comprehensive proteomics data analysis. We use this framework to expose a prototype version of our recently proposed common API (mzAPI) designed for direct access to proprietary mass spectrometry files. In addition to routine data analytic tasks, multiplierz supports generation of information rich, portable spreadsheet-based reports. Moreover, multiplierz is designed around a "zero infrastructure" philosophy, meaning that it can be deployed by end users with little or no system administration support. Finally, access to multiplierz functionality is provided via high-level Python scripts, resulting in a fully extensible data analytic environment for rapid development of custom algorithms and deployment of high-throughput data pipelines. CONCLUSION. Collectively, mzAPI and multiplierz facilitate a wide range of data analysis tasks, spanning technology development to biological annotation, for mass spectrometry-based proteomics research.Dana-Farber Cancer Institute; National Human Genome Research Institute (P50HG004233); National Science Foundation Integrative Graduate Education and Research Traineeship grant (DGE-0654108
ARISTO: ontological classification of small molecules by electron ionization-mass spectrometry
Gas chromatography–mass spectrometry (GC–MS) acquisitions routinely yield hundreds to thousands of Electron Ionization (EI) mass spectra. The chemical identification of these spectra typically involves a search protocol that seeks an exact match to a reference spectrum. Reference spectra are found in comprehensive libraries of small molecule EI spectra curated by commercial and public entities. We developed ARISTO (Automatic Reduction of Ion Spectra To Ontology), a webtool, which provides information regarding the general chemical nature of the compound underlying an input EI mass spectrum. Importantly, ARISTO can provide such annotation without necessitating an exact match to a specific compound. ARISTO provides assignments to a subset of the ChEBI (Chemical Entities of Biological Interest) dictionary, an ontology, which aims to cover biologically relevant small molecules. Our system takes as input a mass spectrum represented as a series of mass and intensity pairs; the system returns a graphical representation of the supported ontology as well as a detailed table of suggested annotations along with their associated statistical evidence. ARISTO is accessible at this URL: http://www.ionspectra.org/aristo. The system is free, open to all and does not require registration of any sort
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