Development of ceramic matrix composites for 2500°F turbine engine applications

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What Matters? An Analysis of Teacher Training, Student Achievement, and Teacher Attrition in North Carolina.

Using a quantitative approach that draws on qualitative methods, this study aimed to identify what, if any, elements within an elementary teacher preparation program have a relationship between elementary student achievement gains in reading and math as well as a teacher’s attrition. This study identified elements of teacher training programs through interviews, program document reviews, and surveys of training programs in North Carolina. I used data from the North Carolina Education Resource Data Center (NCERDC) for the years 2014-2018 to test relationships between program elements, student achievement, and teacher attrition using a covariate adjusted multilevel linear model and a school fixed effects model. Results showed that attendance at certain training programs themselves can increase student achievement in math and reading, as well as a teacher’s attrition. Furthermore, there were signs that specific courses in the training program (such as subject matter) can also impact a student’s learning and teacher attrition. Specifically, there were two elements of training techniques themselves that showed an impact on student achievement and teacher attrition: recording a candidate’s teaching practice in student teaching experiences and lessons on instructional technology. Such findings suggest elements within training likely matter as much as the overall training requirements and more research is needed within programs to test the effects of elements themselves, as well as the quality of the element on student and teacher outcome

Modulation of MEG signals during overt and imagined wrist movement for brain-computer interfaces

This work uses Magnetoencephalography (MEG) to investigate movement-related neural activity in the cerebral cortex. MEG is an efficient non-invasive tool to study cortical activity because it has higher temporal and spatial resolutions than other non-invasive methods, such as fMRI and EEG. One objective of the proposed study is to characterize MEG signal modulation during overt and imagined movements. Such characterization can then be implemented to study motor control and cortical plasticity. In the future, this information can be used to aid the mapping of motor regions of the brain prior to surgical implantation of electrodes for a brain-computer interface (BCI). For the current experiments, four right-handed subjects were asked to perform wrist movements with their dominant hand in four directions (radial deviation, ulnar deviation, flexion, and extension) following a visual cue (up, down, left, and right, respectively). In separate sessions, subjects were then asked to imagine performing the same movements following the visual cue. Frequency-domain analysis of the MEG signals reveals consistent modulation during both overt and imagined movements on sensors overlaying sensorimotor areas of the brain. Modulation preceded movement onset and was characterized as an inhibition in low frequency bands (10-30Hz) and excitation of lower bands (0-10Hz), starting 200 ms after the visual cue and lasting 500 ms, which was accompanied by an increase of power in the 65-90Hz band during the same period. This sequence is followed by an increase in power in the 10-30Hz band. Several of these modulations in cortical activity were also significantly tuned (p < 0.05) to the direction of movement in both overt and imaginary tasks. Two methods were used for decoding: Optimal Linear Estimator (OLE) and Bayesian. The decoding accuracy of a given target for the imagined wrist movement data varied among subjects from 29.4% to 49.75% (mean: 41.4%) correct trials for OLE, and 30.1% to 50.9% (mean: 41.5%) for Bayesian. For overt wrist movement data, decoding accuracy for a given target ranged from 34.1% to 67.4% (mean: 48.3%) correct trials for OLE, and 33.1% to 66.9% (mean: 48.0%) for Bayesian. MEG can detect cortical areas that show directionally tuned modulation during overt and imagined wrist movement. We conclude that MEG may be an important tool for the development of BCIs, and for the identification of regions for future insertion of electrodes for neuroprosthetic control

Generalised Dice overlap as a deep learning loss function for highly unbalanced segmentations

Deep-learning has proved in recent years to be a powerful tool for image analysis and is now widely used to segment both 2D and 3D medical images. Deep-learning segmentation frameworks rely not only on the choice of network architecture but also on the choice of loss function. When the segmentation process targets rare observations, a severe class imbalance is likely to occur between candidate labels, thus resulting in sub-optimal performance. In order to mitigate this issue, strategies such as the weighted cross-entropy function, the sensitivity function or the Dice loss function, have been proposed. In this work, we investigate the behavior of these loss functions and their sensitivity to learning rate tuning in the presence of different rates of label imbalance across 2D and 3D segmentation tasks. We also propose to use the class re-balancing properties of the Generalized Dice overlap, a known metric for segmentation assessment, as a robust and accurate deep-learning loss function for unbalanced tasks

Elementos metaficcionales en at swim-two-birds, de flann o’brien

Following a visit to the MNHN in Paris, and from the study of four types of the Dresden Museum as well as from personal observations, we provide some new synonymies as a result of types comparisons.Suite à une visite effectuée par l'un de nous aux collections du laboratoire d'entomologie du MNHN de Paris, et suite à l'examen de quatre types conservés au musée de Dresde, ainsi qu'au travers d'observations personnelles, des synonymies nouvelles ont pu être établies par comparaison de divers types.Sudre Jérôme, Téocchi Pierre. Notes synonymiques et chorologie concernant quelques Lamiaires africains (Insecta, Coleoptera, Cerambycidae, Lamiinae) . In: Bulletin mensuel de la Société linnéenne de Lyon, 78ᵉ année, n°5-6, Mai-juin 2009. pp. 105-110

Surface mixing and biological activity in the four Eastern Boundary Upwelling Systems

Eastern Boundary Upwelling Systems (EBUS) are characterized by a high productivity of plankton associated with large commercial fisheries, thus playing key biological and socio-economical roles. The aim of this work is to make a comparative study of these four upwelling systems focussing on their surface stirring, using the Finite Size Lyapunov Exponents (FSLEs), and their biological activity, based on satellite data. First, the spatial distribution of horizontal mixing is analysed from time averages and from probability density functions of FSLEs. Then we studied the temporal variability of surface stirring focussing on the annual and seasonal cycle. There is a global negative correlation between surface horizontal mixing and chlorophyll standing stocks over the four areas. To try to better understand this inverse relationship, we consider the vertical dimension by looking at the Ekman-transport and vertical velocities. We suggest the possibility of a changing response of the phytoplankton to sub/mesoscale turbulence, from a negative effect in the very productive coastal areas to a positive one in the open ocean.Comment: 12 pages. NPG Special Issue on "Nonlinear processes in oceanic and atmospheric flows". Open Access paper, available also at the publisher site: http://www.nonlin-processes-geophys.net/16/557/2009

Air traffic

This report presents a recounting of the steps taken by France to establish national and international regulation over air traffic

Wetting Transition on Hydrophobic Surfaces Covered by Polyelectrolyte Brushes

International audienceWe study the wetting by water of complex “hydrophobic-hydrophilic” surfaces made of a hydrophobic substrate covered by a hydrophilic polymer brush. Polystyrene (PS) substrates covered with polystyrene-block-poly(acrylic acid) PS-b-PAA diblock copolymer layers were fabricated by Langmuir-Schaefer depositions and analyzed by atomic force microscopy (AFM) and ellipsometry. On bare PS substrate, we measured advancing angles θA ) 93 ( 1° and receding angles θR ) 81 ( 1°. On PS covered with poorly anchored PS-b-PAA layers, we observed large contact angle hysteresis, θA ≈ 90° and θR ≈ 0°, that we attributed to nanometric scale dewetting of the PS-b-PAA layers. On well-anchored PS-b-PAA layers that form homogeneous PAA brushes, a wetting transition from partial to total wetting occurs versus the amount deposited: both θA and θR decrease close to zero. A model is proposed, based on the Young-Dupre´ equation, that takes into account the interfacial pressure of the brush Π, which was determined experimentally, and the free energy of hydration of the polyelectrolyte monomers ΔGPAA hyd , which is the only fitting parameter. With ΔGPAA hyd ≈ -1300 J/mol, the model renders the wetting transition for all samples and explains why the wetting transition depends mainly on the average thickness of the brush and weakly on the length of PAA chains

HPV vaccination coverage within 3years of program launching (2008-2011) at Geneva State, Switzerland

Objective: The objective of this study is to assess the HPV vaccination coverage of 11-19-year-old girls during a state-coordinated HPV vaccination program in Geneva, Switzerland, from September 2008 to June 2011. Methods: State Medical Office coordinated the HPV vaccination program. Each service provider transmitted the list of the persons who had received their first, second, or third shot. Results: The global coverage rates, 3years after the program had been launched, were 63.72% for one dose, 63.22% for two doses, and 61.40% for three doses of the HPV vaccine. Conclusion: This study shows that it is possible to obtain a good coverage rates after 3years of a state-coordinated HPV vaccination progra