2,551 research outputs found

    Capturing flight system test engineering expertise: Lessons learned

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    Within a few years, JPL will be challenged by the most active mission set in history. Concurrently, flight systems are increasingly more complex. Presently, the knowledge to conduct integration and test of spacecraft and large instruments is held by a few key people, each with many years of experience. JPL is in danger of losing a significant amount of this critical expertise, through retirement, during a period when demand for this expertise is rapidly increasing. The most critical issue at hand is to collect and retain this expertise and develop tools that would ensure the ability to successfully perform the integration and test of future spacecraft and large instruments. The proposed solution was to capture and codity a subset of existing knowledge, and to utilize this captured expertise in knowledge-based systems. First year results and activities planned for the second year of this on-going effort are described. Topics discussed include lessons learned in knowledge acquisition and elicitation techniques, life-cycle paradigms, and rapid prototyping of a knowledge-based advisor (Spacecraft Test Assistant) and a hypermedia browser (Test Engineering Browser). The prototype Spacecraft Test Assistant supports a subset of integration and test activities for flight systems. Browser is a hypermedia tool that allows users easy perusal of spacecraft test topics. A knowledge acquisition tool called ConceptFinder which was developed to search through large volumes of data for related concepts is also described and is modified to semi-automate the process of creating hypertext links

    A Caregiver\u27s Perceptions and Practices in Relation to her Speech to an Under 2-year-old age Group in a Childcare Centre

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    The objective of this study was to investigate what a caregiver sees as her role in relation to young children\u27s oral language development. This study examines her perceptions and beliefs, as well as the various activities that she thinks facilitates language development with under 2-year-old children. The main focus of the study is her language interactions with the children while they took part in three activities. The investigation involved qualitative case study research to collect the oral language interactions between the caregiver and the young children and the activities she provides. The features of the caregiver\u27s speech to young children were identified from the research literature. The study was carried out in a community based childcare centre with one caregiver and five under 2-year-old children who were in her care. Results from the investigation suggest that the caregiver’s perceptions and beliefs, the activities she provides and her oral language interactions with the children have the potential to facilitate the children\u27s language development in this childcare centre

    Using content and process scaffolds for collaborative discourse in asynchronous learning networks

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    Discourse, a form of collaborative learning, is one of the most widely used methods of teaching and learning in the online environment. Particularly, in large courses, discourse needs to be \u27structured\u27 to be effective. Historically, technology-mediated learning (TML) research has been inconclusive with often conflicting results. To address this issue, TML research needs greater breadth and depth in pedagogical grounding. The purpose of this research is to build and test an original, technology-mediated, discourse-centered model called the Asynchronous Learning Network Cognitive Discourse Model (ALNCDM) grounded in pedagogy. Cognitive discourse is defined as discourse on conceptual subject matter. The model is aimed at structuring discourse to effect conceptual mastery at the Application level of Bloom\u27s taxonomy. The ALNCDM applies pedagogic principles to provide content and process scaffolding during discourse to increase learning. (Scaffolding is defined as providing support for the learner at his/her level until the support is no longer needed.) The content scaffold consists of a concept structure in the form a matrix, which is unfolded in a sequence following the Veeheuristic. The process scaffold consists of an individual process, modeled after Gagne\u27s Nine Events of Instruction, embedded within a group process, modeled after Gunawardena, Lowe and Anderson\u27s Critical Thinking Model. A research approach was designed and a field experiment conducted to validate the ALNCDM. In the research approach, content and process scaffolds formed the two manipulated variables while the dependent variable, learning effectiveness, was measured using a combination of cognitive and affective assessments. A motivation measure, self-expectancy, was also included in the dependent variables. The main study, a 2X2 between-subjects, pre- and post-test field experiment, was conducted between Fall 2004 and Spring 2005, yielding 172 participants in 58 groups. A major finding from the study is students with SynthesisAnalysis learning approach performed significantly better in two out of three cognitive assessments. While the ALNCDM research approach requires further refinement, correlation/contextual analyses support the overall ALNCDM. Another finding from the study is the lack of undergraduate student motivation

    Cosmology seeking friendship with sterile neutrinos

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    Precision cosmology and big-bang nucleosynthesis mildly favor extra radiation in the universe beyond photons and ordinary neutrinos, lending support to the existence of low-mass sterile neutrinos. We use the WMAP 7-year data, small-scale CMB observations from ACBAR, BICEP and QuAD, the SDSS 7th data release, and measurement of the Hubble parameter from HST observations to derive credible regions for the assumed common mass scale m_s and effective number N_s of thermally excited sterile neutrino states. Our results are compatible with the existence of one or perhaps two sterile neutrinos, as suggested by LSND and MiniBooNE, if m_s is in the sub-eV range.Comment: 4 pages, 1 figure, matches version published in PR

    My bitterness is deeper than the ocean : understanding internalized stigma from the perspectives of persons with schizophrenia and their family caregivers.

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    Background: It is estimated that 8 million of the Chinese adult population had a diagnosis of schizophrenia. Stigma associated with mental illness, which is pervasive in the Chinese cultural context, impacts both persons with schizophrenia and their family caregivers. However, a review of the literature found a dearth of research that explored internalized stigma from the perspectives of both patients and their caregivers. Methods: We integrated data from standardized scales and narratives from semi-structured interviews obtained from eight family-dyads. Interview narratives about stigma were analyzed using directed content analysis and compared with responses from Chinese versions of the Internalized Stigma of Mental Illness Scale and Affiliated Stigma Scale. Scores from the two scales and number of text fragments were compared to identify consistency of responses using the two methods. Profiles from three family-dyads were analyzed to highlight the interactive aspect of stigma in a dyadic relationship. Results: Our analyses suggested that persons with schizophrenia and their caregivers both internalized negative valuation from their social networks and reduced engagement in the community. Participants with schizophrenia expressed a sense of shame and inferiority, spoke about being a burden to their family, and expressed self-disappointment as a result of having a psychiatric diagnosis. Caregivers expressed high level of emotional distress because of mental illness in the family. Family dyads varied in the extent that internalized stigma were experienced by patients and caregivers. Conclusions: Family plays a central role in caring for persons with mental illness in China. Given the increasingly community-based nature of mental health services delivery, understanding internalized stigma as a family unit is important to guide the development of cultural-informed treatments. This pilot study provides a method that can be used to collect data that take into consideration the cultural nuances of Chinese societies

    COMBUSTION OF PYROLYSIS \u27BIO-OILS\u27 IN A TUNNEL FURNACE

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    A test program has been carried out in a pilot-scale (2.5 GJ/h) tunnel furnace to evaluate potential emission levels from combustion of various biomass pyrolysis oil \u27cuts\u27. Two pyrolysis oil cuts were tested: a “whole” oil and a “premium” high moisture (30% H2O) oil, both supplied by Ensyn. A CETC-O designed external mixing air-assisted atomising nozzle originally designed for coal liquid mixtures was used. The oils were preheated to 48 – 52°C. The atomizing air was not preheated and main combustion air preheat was varied from ambient to 120°C. Under steady state operation both pyrolysis oil cuts were found to perform well within the following ranges: O2 4.5 %; CO 45 – 106 ppm and NOx 150 – 250 ppm. The oils were also tested in co-firing mode in which natural gas was added from 10 to 50% of the total heat input. This served to substantially improve the performance of both oil cuts and CO then easily maintained below 50 ppm and total particulates below 50 mg/Nm3. These results were generally independent of natural gas level in the 10 - 50% range and were similar for both cuts of oil

    Trends in Mortality from Septicaemia and Pneumonia with Economic Development: An Age-Period-Cohort Analysis

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    BackgroundHong Kong population has experienced drastic changes in its economic development in the 1940s. Taking advantage of Hong Kong’s unique demographic and socioeconomic history, characterized by massive, punctuated migration waves from Southern China, and recent, rapid transition from a pre-industrialized society to the first ethnic Chinese community reaching ‘‘first world’’ status over the last 60 years (i.e., in two or three generations), we examined the longitudinal trends in infection related mortality including septicemia compared to trends in non-bacterial pneumonia to generate hypotheses for further testing in other recently transitioned economies and to provide generalized aetiological insights on how economic transition affects infection-related mortality. Methods We used deaths from septicemia and pneumonia not specified as bacterial, and population figures in Hong Kong from 1976–2005. We fitted age-period-cohort models to decompose septicemia and non-bacterial pneumonia mortality rates into age, period and cohort effects. Results Septicaemia-related deaths increased exponentially with age, with a downturn by period. The birth cohort curves had downward inflections in both sexes in the 1940s, with a steeper deceleration for women. Non-bacterial pneumoniarelated deaths also increased exponentially with age, but the birth cohort patterns showed no downturns for those born in the 1940s. Conclusion The observed changes appeared to suggest that better early life conditions may enable better development of adaptive immunity, thus enhancing immunity against bacterial infections, with greater benefits for women than men. Given the interaction between the immune system and the gonadotropic axis, these observations are compatible with the hypothesis that upregulation of the gonadotropic axis underlies some of the changes in disease patterns with economic development

    Corporate governance : disclosure on directors’ remuneration in Malaysia – is it adequate?

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    Ever since numerous corporate failures that shaken the faith and confidence of the public, the introduction of good corporate governance mechanism has swept the world off their feet. A sound corporate governance mechanism not only encourages proper management of risk, but at the same time, promotes effective performance. A vital part of corporate governance, directors’ remuneration has gain considerable focus from the policy makers, academics, media and public over the years. The measurements and determinants of the directors’ remuneration has attracts numerous different views and opinions which ultimately landed it as hot-debatable topic. The purpose of this study is to assess the adequacy of Malaysia’s current state on directors’ remuneration disclosure regime with the focus drawn upon six particular banking organisations since banking industry in Malaysia offers a diversified portfolio ranging from government-controlled, family-controlled to foreign-owned where effects of diversified ownership structures can be drawn. The paper outlines several angles: composition of remuneration and levels of remuneration and the process in determining the remuneration package i.e. remuneration committee. The benchmark is acquired by comparing Malaysia’s current disclosure regime with other countries’ regime. The paper concludes that Malaysia’s current disclosure regime is satisfactory but there are still some shortcomings and regulators need to overcome such inadequacies in order to achieve better corporate governance in the international arena

    Magnetic resonance urography of congenital abnormalities - what the radiologist needs to know

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    Congenital abnormalities of the kidney and urinary tract include a wide range of malformations ranging from asymptomatic to life-threatening conditions. Although pediatric urogenital system imaging is based on the use of US (pre- and postnatal), voiding cystourethrography and scintigraphic study, magnetic resonance (MR) urography plays a fundamental role in the classification and management of congenital abnormalities of the kidney and urinary tract, giving an overview of the different clinical pictures, thanks to its panoramicity and high anatomical detail. In fact the anomalies of the urinary tract are phenotypically variable because they can affect simultaneously several segments of different embryonic derivation, with complex clinical pictures; they can appear both as isolated phenotypes or as complex malformative conditions, involving renal parenchyma, collecting system and bladder. A deep knowledge of this complex embryogenesis and its possible phenotypic patterns allows a correct interpretation of MR urography images. We describe the embryology and pathophysiology of congenital abnormalities of the kidney and urinary tract as well as MR urography technique and findings. Congenital abnormalities of the kidney and urinary tract are classified into four groups: (1) obstruction (proximal, middle and distal), (2) budding with respect to the Wolffian duct (site and number of ureter), (3) ascent and rotation (ectopia, malrotation and fusion of kidney) and (4) anomaly of metanephric differentiation (dysplasia, megapolicalycosis)
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