1,490 research outputs found

    Teen Voice 2009: The Untapped Strengths of 15-Year-Olds

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    Based on a survey, explores how interests that give teenagers purpose, engagement with civic and social issues, and relationships and opportunities that encourage and guide them can shape their choices and potential. Recommends actions to support teens

    Adjoint error estimation and spatial adaptivity for EHL-like models

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    The use of adjoint error estimation techniques is described for a model problem that is a simplified version of an EHL line contact. Quantities of interest, such as friction, may be dependent upon the accuracy of the Solution in some parts of the domain more than in others. The use of an inexpensive extra solve to calculate an adjoint solution is described for estimating the intergrid error in the value of friction calculated, and as a basis for local refinement. It is demonstrated that this enables an accurate estimate for the quantity of interest to be obtained from a less accurate solution of the model problem

    Before and After Nationes: Accounting for Medieval Peoples in Twenty-First-Century Germany

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    Honorable John D. Clifford, Jr. A Memoir by His Three Law Clerks

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    The domain over which United States District Judge John D. Clifford, Jr. presided from 1947 until his death in 1956 was very different from what it is today. Anyone could walk into the federal courthouse in Portland. Security guards were unknown, and lawyers, litigants, and passers-by were free to come and go. A leisurely air pervaded all the court offices. There was no hurry. This was an era when there were only two lawyers in the United States Attorney\u27s office: the United States Attorney and his one assistant

    Joint Blind Motion Deblurring and Depth Estimation of Light Field

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    Removing camera motion blur from a single light field is a challenging task since it is highly ill-posed inverse problem. The problem becomes even worse when blur kernel varies spatially due to scene depth variation and high-order camera motion. In this paper, we propose a novel algorithm to estimate all blur model variables jointly, including latent sub-aperture image, camera motion, and scene depth from the blurred 4D light field. Exploiting multi-view nature of a light field relieves the inverse property of the optimization by utilizing strong depth cues and multi-view blur observation. The proposed joint estimation achieves high quality light field deblurring and depth estimation simultaneously under arbitrary 6-DOF camera motion and unconstrained scene depth. Intensive experiment on real and synthetic blurred light field confirms that the proposed algorithm outperforms the state-of-the-art light field deblurring and depth estimation methods

    Millimeter Wave Localization: Slow Light and Enhanced Absorption

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    We exploit millimeter wave technology to measure the reflection and transmission response of random dielectric media. Our samples are easily constructed from random stacks of identical, sub-wavelength quartz and Teflon wafers. The measurement allows us to observe the characteristic transmission resonances associated with localization. We show that these resonances give rise to enhanced attenuation even though the attenuation of homogeneous quartz and Teflon is quite low. We provide experimental evidence of disorder-induced slow light and superluminal group velocities, which, in contrast to photonic crystals, are not associated with any periodicity in the system. Furthermore, we observe localization even though the sample is only about four times the localization length, interpreting our data in terms of an effective cavity model. An algorithm for the retrieval of the internal parameters of random samples (localization length and average absorption rate) from the external measurements of the reflection and transmission coefficients is presented and applied to a particular random sample. The retrieved value of the absorption is in agreement with the directly measured value within the accuracy of the experiment.Comment: revised and expande

    Using e-mail recruitment and an online questionnaire to establish effect size: A worked example

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    Background\ud Sample size calculations require effect size estimations. Sometimes, effect size estimations and standard deviation may not be readily available, particularly if efficacy is unknown because the intervention is new or developing, or the trial targets a new population. In such cases, one way to estimate the effect size is to gather expert opinion. This paper reports the use of a simple strategy to gather expert opinion to estimate a suitable effect size to use in a sample size calculation.\ud \ud Methods\ud Researchers involved in the design and analysis of clinical trials were identified at the University of Birmingham and via the MRC Hubs for Trials Methodology Research. An email invited them to participate.\ud \ud An online questionnaire was developed using the free online tool 'Survey Monkey©'. The questionnaire described an intervention, an electronic participant information sheet (e-PIS), which may increase recruitment rates to a trial. Respondents were asked how much they would need to see recruitment rates increased by, based on 90%. 70%, 50% and 30% baseline rates, (in a hypothetical study) before they would consider using an e-PIS in their research.\ud \ud Analyses comprised simple descriptive statistics.\ud \ud Results\ud The invitation to participate was sent to 122 people; 7 responded to say they were not involved in trial design and could not complete the questionnaire, 64 attempted it, 26 failed to complete it. Thirty-eight people completed the questionnaire and were included in the analysis (response rate 33%; 38/115). Of those who completed the questionnaire 44.7% (17/38) were at the academic grade of research fellow 26.3% (10/38) senior research fellow, and 28.9% (11/38) professor. Dependent upon the baseline recruitment rates presented in the questionnaire, participants wanted recruitment rate to increase from 6.9% to 28.9% before they would consider using the intervention.\ud \ud Conclusions\ud This paper has shown that in situations where effect size estimations cannot be collected from previous research, opinions from researchers and trialists can be quickly and easily collected by conducting a simple study using email recruitment and an online questionnaire. The results collected from the survey were successfully used in sample size calculations for a PhD research study protocol.\ud \u

    Examining the development of memory for temporal order and the neural substrates that support it

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    Episodic memory—memory for events in the context of a particular time and place—is a complex construct with a protracted development. One defining and critical feature of episodic memory is memory for temporal order, or the ability to remember the order of sequences of events (e.g., X happened before Y). Memory for temporal order is largely thought to be dependent on a neural structure in the medial temporal lobe (MTL), the hippocampus. Previous work has shown continued behavioral improvements in episodic memory in general and specifically memory for temporal order across middle to late childhood (i.e. 7-11-years-old). However, the underlying factors contributing to this development are unclear. One factor may be the structural changes in subregions along the longitudinal axis of the hippocampus that also occur during middle to late childhood. However, these behavioral and neural changes have yet to be linked during development. The present study examined, in a group of children (7-11-year-olds) and young adults, age-related differences in performance on a memory for temporal order task, age-related difference in volume along the longitudinal axis of the hippocampus using structural MRI, and the relation between memory performance and hippocampal volume. Age-related improvements were found in both the encoding and retrieval of temporal order. Manual parcellation of the hippocampus replicated previous work: adults had smaller hippocampal head and tail and larger body than children. While no relation between hippocampal subregions and retrieval of temporal order were found, some differential patterns for adults and children emerged for the relation between encoding of temporal order and hippocampal subregions
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