Do High Ability Students Disidentify With Science? A Descriptive Study of U. S. Ninth Graders in 2009

The present study describes science expectancy-value motivation classes within a nationally representative sample of students who were U.S. ninth graders in 2009. An expectancy-value model was the basis for science-specific profile indicators (self-efficacy, attainment value, utility value, interest-enjoyment value). Using exploratory latent class analysis, a four-class model was identified as the best model, based on model fit and interpretability. Although the low and typical profiles had uniform levels of indicators, the two high motivation profiles (high self-efficacy and high utility value) had mixed levels. The profile characterized by very high self-efficacy had lower values, while the profile characterized by high utility value had lower self-efficacy. The differences in math achievement between profiles were small. High-ability students disidentified with science; only 29% of high-ability students had high science expectancy-value profiles. The implications for science talent development are discussed

Performance of Size-Changing Algorithms in Stackable File Systems

Stackable file systems can provide extensible file system functionality with minimal performance overhead and development cost. However, previous approaches are limited in the functionality they provide. In particular, they do not support size-changing algorithms, which are important and useful for many applications, such as compression and security. We propose fast index files, a technique for efficient support of size-changing algorithms in stackable file systems. Fast index files provide a page mapping between file system layers in a way that can be used with any size-changing algorithm. Index files are designed to be recoverable if lost and add less than 0.1\% disk space overhead. We have implemented fast indexing using portable stackable templates, and we have used this system to build several example file systems with size-changing algorithms. We demonstrate that fast index files have very low overhead for typical workloads, only 2.3\% over other stacked file systems. Our system can deliver much better performance on size-changing algorithms than user-level applications, as much as five times faster

Post-transcriptional regulation of satellite cell quiescence by TTP-mediated mRNA decay.

Skeletal muscle satellite cells in their niche are quiescent and upon muscle injury, exit quiescence, proliferate to repair muscle tissue, and self-renew to replenish the satellite cell population. To understand the mechanisms involved in maintaining satellite cell quiescence, we identified gene transcripts that were differentially expressed during satellite cell activation following muscle injury. Transcripts encoding RNA binding proteins were among the most significantly changed and included the mRNA decay factor Tristetraprolin. Tristetraprolin promotes the decay of MyoD mRNA, which encodes a transcriptional regulator of myogenic commitment, via binding to the MyoD mRNA 3' untranslated region. Upon satellite cell activation, p38α/β MAPK phosphorylates MAPKAP2 and inactivates Tristetraprolin, stabilizing MyoD mRNA. Satellite cell specific knockdown of Tristetraprolin precociously activates satellite cells in vivo, enabling MyoD accumulation, differentiation and cell fusion into myofibers. Regulation of mRNAs by Tristetraprolin appears to function as one of several critical post-transcriptional regulatory mechanisms controlling satellite cell homeostasis

Bod1, a novel kinetochore protein required for chromosome biorientation

We have combined the proteomic analysis of Xenopus laevis in vitro–assembled chromosomes with RNA interference and live cell imaging in HeLa cells to identify novel factors required for proper chromosome segregation. The first of these is Bod1, a protein conserved throughout metazoans that associates with a large macromolecular complex and localizes with kinetochores and spindle poles during mitosis. Small interfering RNA depletion of Bod1 in HeLa cells produces elongated mitotic spindles with severe biorientation defects. Bod1-depleted cells form syntelic attachments that can oscillate and generate enough force to separate sister kinetochores, suggesting that microtubule–kinetochore interactions were intact. Releasing Bod1-depleted cells from a monastrol block increases the frequency of syntelic attachments and the number of cells displaying biorientation defects. Bod1 depletion does not affect the activity or localization of Aurora B but does cause mislocalization of the microtubule depolymerase mitotic centromere- associated kinesin and prevents its efficient phosphorylation by Aurora B. Therefore, Bod1 is a novel kinetochore protein that is required for the detection or resolution of syntelic attachments in mitotic spindles

Minnesat: GPS Attitude Determination Experiments Onboard a Nanosatellite

This paper presents an overview of the attitude determination experiments onboard the University of Minnesota nanosatellite, Minnesat. Minnesat is designed as a test bed for conducting ultra-short baseline GPS attitude determination experiments in Earth orbit. The primary scientific mission of the Minnesat project is to design, develop, and validate an ultra-short baseline GPS attitude determination (AD) system. Minnesat is equipped with a set of sensors to support two independent AD systems that are referred to as the Primary AD System and the GPS AD System. The Primary AD System blends measurements of inertial sensors with measurements of a three-axis magnetometer to estimate Minnesat’s attitude. The GPS AD System blends measurements of inertial sensors with differential carrier phase GPS measurements to estimate Minnesat’s attitude. The Primary AD System is used as a truth source to validate the GPS AD System

Design and evaluation of the ReKon : an integrated detection and assessment perimeter system.

Kontek Industries (Kannapolis, NC) and their subsidiary, Stonewater Control Systems (Kannapolis, NC), have entered into a cooperative research and development agreement with Sandia to jointly develop and evaluate an integrated perimeter security system solution, one that couples access delay with detection and assessment. This novel perimeter solution was designed to be configurable for use at facilities ranging from high-security military sites to commercial power plants, to petro/chemical facilities of various kinds. A prototype section of the perimeter has been produced and installed at the Sandia Test and Evaluation Center in Albuquerque, NM. This prototype system integrated fiber optic break sensors, active infrared sensors, fence disturbance sensors, video motion detection, and ground sensors. This report documents the design, testing, and performance evaluation of the developed ReKon system. The ability of the system to properly detect pedestrian or vehicle attempts to bypass, breach, or otherwise defeat the system is characterized, as well as the Nuisance Alarm Rate

On the segmentation and classification of hand radiographs

This research is part of a wider project to build predictive models of bone age using hand radiograph images. We examine ways of finding the outline of a hand from an X-ray as the first stage in segmenting the image into constituent bones. We assess a variety of algorithms including contouring, which has not previously been used in this context. We introduce a novel ensemble algorithm for combining outlines using two voting schemes, a likelihood ratio test and dynamic time warping (DTW). Our goal is to minimize the human intervention required, hence we investigate alternative ways of training a classifier to determine whether an outline is in fact correct or not. We evaluate outlining and classification on a set of 1370 images. We conclude that ensembling with DTW improves performance of all outlining algorithms, that the contouring algorithm used with the DTW ensemble performs the best of those assessed, and that the most effective classifier of hand outlines assessed is a random forest applied to outlines transformed into principal components

Aerosolized adenovirus-vectored vaccine as an alternative vaccine delivery method

Conventional parenteral injection of vaccines is limited in its ability to induce locally-produced immune responses in the respiratory tract, and has logistical disadvantages in widespread vaccine administration. Recent studies suggest that intranasal delivery or vaccination in the respiratory tract with recombinant viral vectors can enhance immunogenicity and protection against respiratory diseases such as influenza and tuberculosis, and can offer more broad-based generalized protection by eliciting durable mucosal immune responses. Controlled aerosolization is a method to minimize vaccine particle size and ensure delivery to the lower respiratory tract. Here, we characterize the dynamics of aerosolization and show the effects of vaccine concentration on particle size, vector viability, and the actual delivered dose of an aerosolized adenoviral vector. In addition, we demonstrate that aerosol delivery of a recombinant adenoviral vaccine encoding H1N1 hemagglutinin is immunogenic and protects ferrets against homologous viral challenge. Overall, aerosol delivery offers comparable protection to intramuscular injection, and represents an attractive vaccine delivery method for broad-based immunization campaigns