Engineering intelligent tutoring systems

We have defined an object-oriented software architecture for Intelligent Tutoring Systems (ITS's) to facilitate the rapid development, testing, and fielding of ITS's. This software architecture partitions the functionality of the ITS into a collection of software components with well-defined interfaces and execution concept. The architecture was designed to isolate advanced technology components, partition domain dependencies, take advantage of the increased availability of commercial software packages, and reduce the risks involved in acquiring ITS's. A key component of the architecture, the Executive, is a publish and subscribe message handling component that coordinates all communication between ITS components

Continued investigation of LDEF's structural frame and thermal blankets by the Meteoroid and Debris Special Investigation Group

This report focuses on the data acquired by detailed examination of LDEF intercostals, 68 of which are now in possession of the Meteoroid and Debris Special Investigation Group (M&D SIG) at JSC. In addition, limited data will be presented for several small sections from the A0178 thermal control blankets that were examined/counted prior to being shipped to Principal Investigators (PI's) for scientific study. The data presented here are limited to measurements of crater and penetration-hole diameters and their frequency of occurrence which permits, yet also constrains, more model-dependent, interpretative efforts. Such efforts will focus on the conversion of crater and penetration-hole sizes to projectile diameters (and masses), on absolute particle fluxes, and on the distribution of particle-encounter velocities. These are all complex issues that presently cannot be pursued without making various assumptions which relate, in part, to crater-scaling relationships, and to assumed trajectories of natural and man-made particle populations in LEO that control the initial impact conditions

Addition of hip exercises to treatment of patellofemoral pain syndrome: A meta-analysis

AIM: To determine if the addition of hip-strengthening exercises decreases pain and improves function in patients with patellofemoral pain syndrome. METHODS: The authors completed a systematic review searching eight databases (i.e. , PubMed, Cochrane, CINHAL, MEDLINE, SportsDiscus, EMBASE, APTA Hooked on Evidence, and PEDro). Two independent reviewers screened and excluded studies if they did not meet the following inclusion criteria: subjects had a primary diagnosis of patellofemoral pain syndrome (PFPS), intervention group included hip-strengthening exercises, control group included a traditional physical therapy intervention, study included outcome measures of pain and/or function, study used a randomized controlled trial design, PEDro score was ≥ 7, and study was published in a peer-reviewed journal. Primary outcome measures were subjective scales of pain and function. These measures were converted to standardized mean difference [effect size (ES)], and a random-effects model was used to calculate the overall ES. RESULTS: Two hundred eighty-three studies were screened for inclusion in our meta-analysis. Nine studies were deemed suitable for data extraction and analysis. A total of 426 subjects were used in the nine studies. Overall, there was a significant positive effect of hip-strengthening exercises on measures of pain and function in subjects with PFPS (ES = 0.94, P = 0.00004). None of the individual studies had a negative ES, with study ES ranging from 0.35 to 2.59. Because of the high degree of between-study variance (I 2 = 76%; Q = 34.0, P \u3c 0.001), subgroup meta-analyses and meta-regressions were performed. None of the potential moderator variables that were investigated (e.g. , outcome type, hip region targeted, duration of treatment) could explain a significant amount of the between-study variance in ES (P ≥ 0.23). CONCLUSION: Overall, the addition of hip-strengthening exercises to traditional physical therapy produced greater improvements in measures of pain and function

Millisecond Pulsars: Detectable Sources of Continuous Gravitational Waves?

Laboratory searches for the detection of gravitational waves have focused on the detection of burst signals emitted during a supernova explosion, but have not resulted in any confirmed detections. An alternative approach has been to search for continuous wave (CW) gravitational radiation from the Crab pulsar. In this paper, we examine the possibility of detecting CW gravitational radiation from pulsars and show that nearby millisecond pulsars are generally much better candidates. We show that the minimum strain h_c ~ 10E-26 that can be detected by tuning an antenna to the frequency of the milli- second pulsar PSR 1957+20, with presently available detector technology, is orders of magnitude better than what has been accomplished so far by observing the Crab pulsar, and within an order of magnitude of the maximum strain that may be produced by it. In addition, we point out that there is likely to be a population of rapidly rotating neutron stars (not necessarily radio pulsars) in the solar neighborhood whose spindown evolution is driven by gravitational radiation. We argue that the projected sensitivity of modern resonant detectors is sufficient to detect the subset of this population that lies within 0.1 kpc of the sun.Comment: 17 pages (including 2 Postscript figures), LaTeX file, uses AASTeX macros, accepted for publication in the Astrophysical Journa

POSaM: a fast, flexible, open-source, inkjet oligonucleotide synthesizer and microarrayer

DNA arrays are valuable tools in molecular biology laboratories. Their rapid acceptance was aided by the release of plans for a pin-spotting microarrayer by researchers at Stanford. Inkjet microarraying is a flexible, complementary technique that allows the synthesis of arrays of any oligonucleotide sequences de novo. We describe here an open-source inkjet arrayer capable of rapidly producing sets of unique 9,800-feature arrays

Immune activation and suppression by group B streptococcus in a murine model of urinary tract infection

Group B streptococcus (GBS) is a common commensal of the gastrointestinal and vaginal mucosa and a leading cause of serious infections in newborns, the elderly, and immunocompromised populations. GBS also causes infections of the urinary tract. However, little is known about host responses to GBS urinary tract infection (UTI) or GBS virulence factors that participate in UTI. Here we describe a novel murine model of GBS UTI that may explain some features of GBS urinary tract association in the human host. We observed high titers and heightened histological signs of inflammation and leukocyte recruitment in the GBS-infected kidney. However, extensive inflammation and leukocyte recruitment were not observed in the bladder, suggesting that GBS may suppress bladder inflammation during cystitis. Acute GBS infection induced the localized expression of proinflammatory cytokines interleukin-1α (IL-1α), macrophage inflammatory protein-1α (MIP-1α), MIP-1β, and IL-9, as well as IL-10, more commonly considered an anti-inflammatory cytokine. Using isogenic GBS strains with different capsule structures, we show that capsular sialic acid residues contribute to GBS urinary tract pathogenesis, while high levels of sialic acid O-acetylation attenuate GBS pathogenesis in the setting of UTI, particularly in direct competition experiments. In vitro studies demonstrated that GBS sialic acids participate in the suppression of murine polymorphonuclear leukocyte (PMN) bactericidal activities, in addition to reducing levels of IL-1α, tumor necrosis factor alpha, IL-1β, MIP-1α, and KC produced by PMNs. These studies define several basic molecular and cellular events characterizing GBS UTI in an animal model, showing that GBS participates simultaneously in the activation and suppression of host immune responses in the urinary tract

Current activities and results of the Long Duration Exposure Facility Meteoroid and Debris Special Investigation Group

Fiscal Year 1994 will bring to a close the initial investigative activities associated with the Long Duration Exposure Facility (LDEF). LDEF was a 14-faced spacecraft (i.e., 12-sided cylinder and two ends) which housed 54 different experimental packages in low-Earth orbit (LEO) from Apr. 1984 to Jan. 1990 (i.e., for approx. 5.75 years). Since LDEF's return, the Meteoroid & Debris Special Investigation Group (M&D SIG) has been examining various LDEF components in order to better understand and define the LEO particulate environment. Members of the M&D SIG at JSC in Houston, TX have been contributing to these studies by carefully examining and documenting all impact events found on LDEF's 6061-T6 aluminum Intercostals (i.e., one of the spacecraft's structural frame components). Unlike all other hardware on LDEF, the frame exposed significantly large surface areas of a single homogeneous material in all (i.e., 26) possible LDEF pointing directions. To date, 28 of the 68 Intercostals in the possession of the M&D SIG have been documented. This data, as well as similar information from various LDEF investigators, can be accessed through the M&D SIG Database which is maintained at JSC

Know Your Audience: Designing a Nutrition Education Game for Middle School Kids

Purpose: In recent years video games have emerged as potential tools to tackle obesity. Games that use motion-sensing controllers and interfaces are often used to promote physical activity. Games are also used to impart education about diet, nutrition and health. Our goal in this project is to address childhood obesity through the design, development and implementation of a video game to teach nutrition concepts to middle-school-aged children. Method: Our target audience is middle-school students in a low-income neighborhood in Dallas. To guide us in the game design, we collected data about students’ gaming preferences through surveys, focus groups and student critiques of existing games. The survey addressed students’ choice of gaming platform and frequency of game play. Through focus groups we explored their gaming preferences and opinions on game features. For the critiques, students played nutrition-themed games from the “Apps for Healthy Kids” competition and completed an open-ended survey about those games. Results: We collected data from 76 students (ages 12 – 15 years). 72% of them play games regularly (at least once a week) on consoles while 73% play on portable devices, 68% on computers and 62% play browser-based games. Console games were preferred by 89% of boys but only 56% of girls. The numbers were 81% & 66% for portable devices, but almost the same for computer games and browser-based games. Students preferred action games, games that allowed character customization and games that had multiple levels. Several students are turned off by strong depictions of violence. Students liked the nutrition themed games, but only one game really engaged them. They wanted the food in these games to look real and wanted more familiar food choices. Conclusions: Our observations and height and weight data indicate that malnutrition rather than obesity is likely a bigger problem for these children. Consoles and portable devices were the platforms of choice although there are differences by gender. The results also provide insights into what is likely to work for this audience in terms of game mechanics and game features. The results also reinforce the need for using multiple approaches to collecting data

Middle School Students’ Understanding of Calories, Energy Expenditure and the Nutrition Facts Panel

TORC Abstrac