689 research outputs found
Self-Regulation: A Cross-Sectional Study of Preschool-Age Children
Self-regulation predicts school readiness and consists of âcoolâ and âhotâ self regulation. âCoolâ self-regulation is characterized by inhibition of a dominant response, working memory, and set shifting. âHotâ self-regulation involves inhibition, shifting attention, and regulation of emotion in arousing situations. In this study, self-regulation was measured in 80 preschool-age children (3-5 years). Two âcoolâ tasks (Pencil Tap and Day/Night) were coded for percent correct, and the other two âcoolâ tasks (Dimensional Change Card Sort and Head-Toes-Knees-Shoulders) were coded for total score. The âhotâ task (Snack Delay) was coded for compliance to task demands (no touching of snack/materials until timer beeped while keeping hands flat). As seen for all tasks, the 4 year-old participants demonstrated better scores than the 3-year-old participants. For Snack Delay, 4-year-olds demonstrated a slightly longer wait with their hands flat than 3 year-old participants, in general. Also, for snack delay, both age groups demonstrated very poor success rates for all 10 trials. Pencil Tap and Head-Toes-Knees-Shoulders showed significant age effects, demonstrating that 4-year-old children showed significantly better performance than 3-year-old children. Dimensional Change Card Sort, Day/Night, and Snack Delay yielded no significant age effects. No effects of gender were found
A Chronic Toxicity Assessment of an Industrial Effluent Utilizing Pimephales Promelas and Ceriodaphnia Sp
A thesis presented to the faculty of the College of Arts and Sciences at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science in Biology by Sharon J. Whitaker Fugate on July 23, 1990
Arc-Smooth Continua
Continua admitting arc-structures and arc-smooth continua are introduced as higher dimensional analogues of dendroids and smooth dendroids, respectively. These continua include such spaces as: cones over compacta, convex continua in l2, strongly convex metric continua, injectively metrizable continua, as well as various topological semigroups, partially ordered spaces, and hyperspaces. The arc-smooth continua are shown to coincide with the freely contractible continua and with the metric K-spaces of Stadtlander. Known characterizations of smoothness in dendroids involving closed partial orders, the set function T, radially convex metrics, continuous selections, and order preserving mappings are extended to the setting of continua with arc-structures. Various consequences of the special contractibility properties of arc-smooth continua are also obtained
Using Item Response Theory to Improve Locally-Constructed Multiple Choice Tests: Measuring Knowledge Gains and Curricular Effectiveness
Current science education reform efforts emphasize teaching K-12 science using hands-on, inquiry activities. For maximum learning and probability of implementation among inservice teachers, these strategies must be modeled in college science courses for preservice teachers. About a decade ago, Morehead State University revised their science content courses to follow an inquiry approach. As part of the coursesâ assessment, a locally-made, diagnostic pre- and post-test was prepared. The main purpose of this âex post factoâ study was to demonstrate how concepts from Item Response Theory can be used to detect and remove psychometrically faulty items, and how the remaining items can be used by teachers to determine science learning gains in an inquiry-based physical science course that implemented two different curricula, âPhysics and Everyday Thinkingâ and âInteractions in Physical Scienceâ
LASER: Light, Accurate Sharing dEtection and Repair
Contention for shared memory, in the forms of true sharing and false sharing, is a challenging performance bug to discover and to repair. Understanding cache contention requires global knowledge of the program\u27s actual sharing behavior, and can even arise invisibly in the program due to the opaque decisions of the memory allocator. Previous schemes have focused only on false sharing, and impose significant performance penalties or require non-trivial alterations to the operating system or runtime system environment.
This paper presents the Light, Accurate Sharing dEtection and Repair (LASER) system, which leverages new performance counter capabilities available on Intel\u27s Haswell architecture that identify the source of expensive cache coherence events. Using records of these events generated by the hardware, we build a system for online contention detection and repair that operates with low performance overhead and does not require any invasive program, compiler or operating system changes. Our experiments show that LASER imposes just 2% average runtime overhead on the Phoenix, Parsec and Splash2x benchmarks. LASER can automatically improve the performance of programs by up to 19% on commodity hardware
Laser Guide Stars for Extremely Large Telescopes: Efficient Shack-Hartmann Wavefront Sensor Design using Weighted center-of-gravity algorithm
Over the last few years increasing consideration has been given to the study
of Laser Guide Stars (LGS) for the measurement of the disturbance introduced by
the atmosphere in optical and near-infrared astronomical observations from the
ground. A possible method for the generation of a LGS is the excitation of the
Sodium layer in the upper atmosphere at approximately 90 km of altitude. Since
the Sodium layer is approximately 10 km thick, the artificial reference source
looks elongated, especially when observed from the edge of a large aperture.
The spot elongation strongly limits the performance of the most common
wavefront sensors. The centroiding accuracy in a Shack-Hartmann wavefront
sensor, for instance, decreases proportionally to the elongation (in a photon
noise dominated regime). To compensate for this effect a straightforward
solution is to increase the laser power, i.e. to increase the number of
detected photons per subaperture. The scope of the work presented in this paper
is twofold: an analysis of the performance of the Weighted Center of Gravity
algorithm for centroiding with elongated spots and the determination of the
required number of photons to achieve a certain average wavefront error over
the telescope aperture.Comment: 10 pages, 14 figure
Embedded Sensors and Controls to Improve Component Performance and Reliability Conceptual Design Report
The objective of this project is to demonstrate improved reliability and increased performance made possible by deeply embedding instrumentation and controls (I&C) in nuclear power plant (NPP) components and systems. The project is employing a highly instrumented canned rotor, magnetic bearing, fluoride salt pump as its I&C technology demonstration platform. I&C is intimately part of the basic millisecond-by-millisecond functioning of the system; treating I&C as an integral part of the system design is innovative and will allow significant improvement in capabilities and performance. As systems become more complex and greater performance is required, traditional I&C design techniques become inadequate and more advanced I&C needs to be applied. New I&C techniques enable optimal and reliable performance and tolerance of noise and uncertainties in the system rather than merely monitoring quasistable performance. Traditionally, I&C has been incorporated in NPP components after the design is nearly complete; adequate performance was obtained through over-design. By incorporating I&C at the beginning of the design phase, the control system can provide superior performance and reliability and enable designs that are otherwise impossible. This report describes the progress and status of the project and provides a conceptual design overview for the platform to demonstrate the performance and reliability improvements enabled by advanced embedded I&C
Solid-state laser system for laser cooling of Sodium
We demonstrate a frequency-stabilized, all-solid laser source at 589 nm with
up to 800 mW output power. The laser relies on sum-frequency generation from
two laser sources at 1064 nm and 1319 nm through a PPKTP crystal in a
doubly-resonant cavity. We obtain conversion efficiency as high as 2 W/W^2
after optimization of the cavity parameters. The output wavelength is tunable
over 60 GHz, which is sufficient to lock on the Sodium D2 line. The robustness,
beam quality, spectral narrowness and tunability of our source make it an
alternative to dye lasers for atomic physics experiments with Sodium atoms
Is it dangerous? The role of an emotional visual search strategy and threatârelevant training in the detection of guns and knives
Counterâterrorism strategies rely on the assumption that it is possible to increase threat detection by providing explicit verbal instructions to orient people's attention to dangerous objects and hostile behaviours in their environment. Nevertheless, whether verbal cues can be used to enhance threat detection performance under laboratory conditions is currently unclear. In Experiment 1, student participants were required to detect a picture of a dangerous or neutral object embedded within a visual search display on the basis of an emotional strategy âis it dangerous?â or a semantic strategy âis it an object?â. The results showed a threat superiority effect that was enhanced by the emotional visual search strategy. In Experiment 2, whilst trainee police officers displayed a greater threat superiority effect than student controls, both groups benefitted from performing the task under the emotional than semantic visual search strategy. Manipulating situational threat levels (high vs. low) in the experimental instructions had no effect on visual search performance. The current findings provide new support for the languageâasâcontext hypothesis. They are also consistent with a dualâprocessing account of threat detection involving a verbally mediated route in working memory and the deployment of a visual template developed as a function of training
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