418 research outputs found

    Describing astronomy identity of upper primary and middle school students through structural equation modeling

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    We describe how young students situate themselves with respect to astronomy through an identity framework that features four dimensions: interest, utility value, confidence, and conceptual knowledge. Overall, about 900 Italian students, from 5th to 9th grade (9-14 years old), were involved in the study. We tested our model using confirmatory factor analysis and structural equation modeling. Differences between girls and boys and across school levels were also investigated. Results show that interest has both a direct and an indirect effect on astronomy identity. The indirect effect of interest on identity is mediated by utility value. Moreover, confidence mediates the effect of interest on conceptual knowledge. Concerning differences between girls and boys, we found that the effect of interest on identity is greater for girls than for boys and that the utility value mediates the effect of interest on identity for boys but not for girls. Finally, our findings show also that the students' interest in astronomy and confidence in their performance decrease with age, with a potential negative impact on conceptual knowledge and future career choice in astronomy. The astronomy identity framework can be employed to examine the role of affective variables on performance and persistence in astronomy and to improve the design of teaching-learning activities that can potentially stimulate a lasting interest in astronomy

    Implementation and Validation of 3-D Ice Accretion Measurement Methodology

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    A research program has been implemented to develop and validate the use of a commercial 3-D laser scanning system to record ice accretion geometry in the NASA Icing Research Tunnel. A main component of the program was the geometric assessment of the 3- D laser scanning system on a 2-D (straight wing) and a 3-D (swept wing) airfoil geometries. This exercise consisted of comparison of scanned ice accretion to castings of the same ice accretion. The scan data were also used to create rapid prototype artificial ice shapes that were scanned and compared to the original ice accretion. The results from geometric comparisons on the straight wing showed that the ice shape models generated through the scan/rapid prototype process compared reasonably well with the cast shapes. Similar results were obtained with the geometric comparisons on the swept wing. It was difficult to precisely compare the scans of the cast shapes to the original ice accretion scans because the cast shapes appear to have shrunk during the mold/casting process by as much as 0.10-inch. However the comparison of the local ice-shape features were possible and produced better results. The rapid prototype manufacturing process was shown to reproduce the original ice accretion scan normally within 0.01-inch

    Measuring urban social sustainability:Scale development and validation

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    Despite the significant role of social sustainability in the sustainable development agenda, there is a lack of research to clearly define and fully operationalise the concept of urban social sustainability. The aim of this study is to contribute to the existing literature by developing a comprehensive measurement scale to assess urban social sustainability at the neighbourhood level. We argue that urban social sustainability is a multidimensional concept that incorporates six main dimensions of social interaction, sense of place, social participation, safety, social equity and neighbourhood satisfaction. Failure to consider each of these dimensions may lead to an incomplete picture of social sustainability. Validity, reliability and dimensionality of the urban social sustainability scale are examined using factor analysis. We also illustrate the application of the urban social sustainability scale by investigating the influence of quality of design, as one of the least studied factors of urban form, on different dimensions of social sustainability. The paper uses data collected from the household questionnaire survey in a sample of 251 respondents from five case study neighbourhoods of Dunedin city, New Zealand. This study provides new evidence on the significance of improving neighbourhood quality of design and its positive and significant relationship with different dimensions of social sustainability and the overall social sustainability

    postoperative mr imaging of spontaneous transdural spinal cord herniation expected findings and complications

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    BACKGROUND AND PURPOSE: Spontaneous transdural spinal cord herniation is no longer a rare cause of myelopathy. The high frequency of diagnoses has led to an increase in the number of surgical procedures. The purpose of this study was to describe the spectrum of postoperative MR imaging findings concerning spontaneous transdural spinal cord herniation and to provide a practical imaging approach for differentiating expected changes and complications after an operation. MATERIALS AND METHODS: We retrospectively reviewed MR images from 12 patients surgically treated for spontaneous transdural spinal cord herniation. Surgery comprised either dural defect enlargement or duraplasty procedures. Postoperative follow-ups included at least 3 (early, intermediate, late) MR imaging studies. MR images were analyzed with respect to 3 spinal compartments: intradural intramedullary, intradural extramedullary, and extradural. The meaning and reliability of changes detected on MR images were related to their radiologic and clinical evolution with time. RESULTS: Spinal cord realignment has been stable since the early study, whereas spinal cord signal and thickness evolved during the following scans. Most extramedullary and extradural changes gradually reduced in later MR images. Three patients treated with dural defect enlargements experienced the onset of new neurologic symptoms. In those patients, late MR images showed extradural fluid collection and the development of pial siderosis. CONCLUSIONS: Our findings demonstrate the spectrum of postoperative imaging findings in spontaneous transdural spinal cord herniation. Spinal cord thickness and signal intensity continued to evolve with time; most extramedullary postsurgical changes became stable. Changes observed in later images may be suggestive of complications

    Mining Stable Roles in RBAC

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    Abstract In this paper we address the problem of generating a candidate role set for an RBAC configuration that enjoys the following two key features: it minimizes the admin-istration cost; and, it is a stable candidate role-set. To achieve these goals, we implement a three steps methodology: first, we associate a weight to roles; second, we identify and remove the user-permission assignments that can not belong to a role having a weight ex-ceeding a given threshold; third, we restrict the problem of finding a candidate role-set for the given system configuration using only the user-permission assignments that have not been removed in step two (that is, user-permission assignments that belong to roles having a weight exceeding the given threshold). We formally show —proof of our results are rooted in graph theory — that this methodol-ogy achieves the intended goals. Finally, we discuss practical applications of our approach to the role mining problem.

    Primary solitary retro-clival amyloidoma.

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    Amyloidosis encompasses a group of disorders sharing the common feature of intercellular deposition of amyloid protein by several different pathogenetic mechanisms. Primary solitary amyloidosis, or amyloidoma, is a rare subset of amyloidosis in which amyloid deposition is focal and not secondary to a systemic process or plasma cell dyscrasia.This 84-year-old female presented with history of multiple syncopal episodes, dysphagia, and ataxia. Motor strength was 3+/5 in the right upper extremity. Rheumatoid factor, cyclic citrullinated peptide (CCP), and anti-nuclear antibody (ANA) were normal. Serum and urine immune-electrophoresis detected no abnormal bands. Computed tomography (CT) and magnetic resonance imaging (MRI) demonstrated a non-enhancing soft-tissue mass extending from the retro-clivus to C2 posteriorly, eccentric to the right with severe mass effect on the upper cervical medullary junction. Endoscopic trans-nasal debulking of the retro-clival mass was performed with occiput to C5 posterior instrumentation for spinal stabilization.Primary solitary amyloidosis, unlike other forms of amyloidosis, has an excellent prognosis with local resection. Diagnosis requires special stains and a degree of suspicion for the disease. This is the first report to document an endoscopic trans-nasal approach for removal of a primary solitary amyloidosis of the retro-clivus. Management of vertebral amyloidoma involves aggressive local resection of the tumor when feasible and spine stabilization as the degree of tumor involvement mandates. Complete evaluation for the diagnosis of systemic amyloidosis is essential for the management and prognostication. Surgeons encountering such lesions must maintain high suspicion for this rare disease and advise pathologists accordingly to establish the correct diagnosis

    Face morphology: Can it tell us something about body weight and fat?

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    This paper proposes a method for an automatic extraction of geometric features, related to weight parameters, from 3D facial data acquired with low-cost depth scanners. The novelty of the method relies both on the processing of the 3D facial data and on the definition of the geometric features which are conceptually simple, robust against noise and pose estimation errors, computationally efficient, invariant with respect to rotation, translation, and scale changes. Experimental results show that these measurements are highly correlated with weight, BMI, and neck circumference, and well correlated with waist and hip circumference, which are markers of central obesity. Therefore the proposed method strongly supports the development of interactive, non-obtrusive systems able to provide a support for the detection of weight-related problems

    Defining neurotrauma in administrative data using the International Classification of Diseases Tenth Revision

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    Abstract Background It is essential to use a definition that is precise and accurate for the surveillance of traumatic brain injuries (TBI) and spinal cord injuries (SCI). This paper reviews the International Classification of Diseases 10th revision (ICD-10) definitions used internationally to inform the definition for neurotrauma surveillance using administrative data in Ontario, Canada. Methods PubMed, Web of Science, Medline and the grey literature were searched for keywords "spinal cord injuries" or "brain injuries" and "international classification of diseases". All papers and reports that used an ICD-10 definition were included. To determine the ICD-10 codes for inclusion consensus across papers and additional evidence were sought to look at the correlation between the condition and brain or spinal injuries. Results Twenty-four articles and reports were identified; 15 unique definitions for TBI and 7 for SCI were found. The definitions recommended for use in Ontario by this paper are F07.2, S02.0, S02.1, S02.3, S02.7, S02.8, S02.9, S06, S07.1, T90.2, and T90.5 for traumatic brain injuries and S14.0, S14.1, S24.0, S24.1, S34.1, S34.0, S34.3, T06.0, T06.1 and T91.3 for spinal cord injuries. Conclusions Internationally, inconsistent definitions are used to define brain and spinal cord injuries. An abstraction study of data would be an asset in understanding the effects of inclusion and exclusion of codes in the definition. This paper offers a definition of neurotrauma for surveillance in Ontario, but the definition could be applied to other countries that have mandated administrative data collection

    Phase 2 study of NAB-paclitaxel in SensiTivE and refractory relapsed small cell lung cancer (SCLC) (NABSTER TRIAL)

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    Background: Despite sensitivity to first-line chemotherapy, most small-cell lung cancer (SCLC) patients relapse. In this setting, topotecan demonstrated modest activity with significant toxicity. Paclitaxel was also active. This study was designed to evaluate activity and safety of nab-paclitaxel in relapsed SCLC. Methods: In this multicentre prospective Phase 2 trial, patients with refractory or sensitive SCLC progressed to first-line platinum-based chemotherapy received nab-paclitaxel 100 mg/smq on days 1, 8, 15 every 4 weeks up to six cycles, progressive disease or intolerable toxicity. Primary endpoint was investigator-assessed objective tumour response. Secondary endpoints were toxicity, progression-free survival (PFS) and overall survival (OS). Results: Of the 68 patients treated, partial response was 8% in the refractory cohort and 14% in the sensitive cohort. Most common toxicities of any grade were fatigue (54%), anaemia (38%), neutropenia (29%), leukopenia (26%) and diarrhoea (21%). Median PFS was similar in both refractory (1.8 months) and sensitive cohorts (1.9 months), while median OS was longer in sensitive one (6.6 versus 3.6 months). Conclusions: Although nab-paclitaxel has shown some modest anti-tumour activity in relapsed SCLC, associated with a favourable toxicity profile, the primary end-point of the study was not met. Clinical Trial registration: Clinical Trial registration number is ClinicalTrials.gov Identifier: NCT03219762
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