Exploring the structure of digital literacy competence assessed using authentic software applications

Digital literacy competence (DL) is an important capacity for students' learning in a rapidly changing world. However, little is known about the empirical structure of DL. In this paper, we review major DL assessment frameworks and explore the dimensionality of DL from an empirical perspective using assessment data collected using authentic software applications, rather than simulated assessment environments. Secondary analysis on representative data collected from primary and secondary school students in Hong Kong using unidimensional and multidimensional item response theory reveals a general dimension of digital literacy performance and four specific, tool-dependent dimensions. These specific DL dimensions are defined by the software applications that students use and capture commonality among students' performance that is due to their familiarity with the assessment tools and contexts. The design of DL assessment is discussed in light of these findings, with particular emphasis on the influence of the nature of digital applications and environments used in assessment on the DL achievement scores measured

HIV testing and care systems focused on sexually transmitted HIV in China

Over three-quarters of new HIV infections in China during 2009 were estimated to be from sexual transmission. Over half of those living with HIV do not know their serostatus and identifying and treating individuals with sexually transmitted HIV infection has been challenging

Three routes to the exact asymptotics for the one-dimensional quantum walk

We demonstrate an alternative method for calculating the asymptotic behaviour of the discrete one-coin quantum walk on the infinite line, via the Jacobi polynomials that arise in the path integral representation. This is significantly easier to use than the Darboux method. It also provides a single integral representation for the wavefunction that works over the full range of positions, $n,$ including throughout the transitional range where the behaviour changes from oscillatory to exponential. Previous analyses of this system have run into difficulties in the transitional range, because the approximations on which they were based break down here. The fact that there are two different kinds of approach to this problem (Path Integral vs. Schr\"{o}dinger wave mechanics) is ultimately a manifestation of the equivalence between the path-integral formulation of quantum mechanics and the original formulation developed in the 1920s. We discuss how and why our approach is related to the two methods that have already been used to analyse these systems.Comment: 25 pages, AMS preprint format, 4 figures as encapsulated postscript. Replaced because there were sign errors in equations (80) & (85) and Lemma 2 of the journal version (v3

Testing abstract behavioral specifications

We present a range of testing techniques for the Abstract Behavioral Specification (ABS) language and apply them to an industrial case study. ABS is a formal modeling language for highly variable, concurrent, component-based systems. The nature of these systems makes them susceptible to the introduction of subtle bugs that are hard to detect in the presence of steady adaptation. While static analysis techniques are available for an abstract language such as ABS, testing is still indispensable and complements analytic methods. We focus on fully automated testing techniques including blackbox and glassbox test generation as well as runtime assertion checking, which are shown to be effective in an industrial setting

Prevalence of acute dizziness and vertigo in cortical stroke

BACKGROUND: In posterior circulation stroke, vertigo can be a presenting feature. However, whether isolated hemispheric strokes present with vertigo is less clear, despite a few single case-reports in the literature. Here we, a) explored the prevalence of vertigo/dizziness in acute stroke and, b) considered the cortical distribution of these lesions in relation to both the known vestibular cortex and evolution of these symptoms. METHODS: We conducted structured interviews in 173 consecutive unselected patients admitted to the hyperacute stroke unit at the University College London Hospitals. The interview was used to evaluate whether the patient was suffering from dizziness and/or vertigo before the onset of the stroke and at the time of the stroke (acute dizziness/vertigo), and the nature of these symptoms. RESULTS: 112 patients had subcortical lesions and 53 patients had cortical infarcts, of which 21 patients reported acute dizziness. Out of these 21, five patients reported rotational vertigo. 17 of the total 53 patients had lesions in known vestibular cortical areas distributed within the insular and parietal opercular cortices. CONCLUSIONS: The prevalence of vertigo in acute cortical strokes was 9%, with no single locus of lesion overlap. There is growing evidence supporting a lateralised vestibular cortex, with speculation that cortical strokes affecting the right hemisphere, are more likely to cause vestibular symptoms than left-hemispheric strokes. We observed a trend for this association, with the right hemisphere affected in four of five patients who reported spinning vertigo at the onset of the stroke

Macro-Architectures in Spinal Cord Scaffold Implants Influence Regeneration

Abstract Biomaterial scaffold architecture has not been investigated as a tunable source of influence on spinal cord regeneration. This study compared regeneration in a transected spinal cord within various designed-macro-architecture scaffolds to determine if these architectures alone could enhance regeneration. Three-dimensional (3-D) designs were created and molds were built on a 3-D printer. Salt-leached porous poly(ε-caprolactone) was cast in five different macro-architectures: cylinder, tube, channel, open-path with core, and open-path without core. The two open-path designs were created in this experiment to compare different supportive aspects of architecture provided by scaffolds and their influence on regeneration. Rats received T8 transections and implanted scaffolds for 1 and 3 months. Overall morphology and orientation of sections were characterized by H&E, luxol fast blue, and cresyl violet staining. Borders between intact gray matter and non-regenerated defect were observed from GFAP immunolabeling. Nerve fibers and regenerating axons were identified with Tuj-1 immunolabeling. The open-path designs allowed extension of myelinated fibers along the length of the defect both exterior to and inside the scaffolds and maintained their original defect length up to 3 months. In contrast, the cylinder, tube, and channel implants had a doubling of defect length from secondary damage and large scar and cyst formation with no neural tissue bridging. The open-path scaffold architectures enhanced spinal cord regeneration compared to the three other designs without the use of biological factors.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63279/1/neu.2007.0473.pd

Inflammatory, Hemostatic, and Other Novel Biomarkers for Diabetic Retinopathy: The Multi-Ethnic Study of Atherosclerosis

Objective— There are conflicting data regarding relationships of systemic biomarkers of inflammation, hemostasis, and homocysteine with diabetic retinopathy. We examined these relationships in the Multi-Ethnic Study of Atherosclerosis. Research design and methods— A total of 921 participants with diabetes were included. Diabetic retinopathy was graded from retinal photographs. We defined two outcomes: any diabetic retinopathy and vision-threatening diabetic retinopathy (severe nonproliferative diabetic retinopathy or worse). Systemic markers analyzed were C-reactive protein, homocysteine, fibrinogen, plasmin- 2-antiplasmin complex (PAP), interleukin-6, D-dimer, factor VIII, serum creatinine, and urinary albumin-to-creatinine (UAC) ratio. Results— Prevalence of diabetic retinopathy was 33.2% and vision-threatening diabetic retinopathy 7.1%. After adjusting for established risk factors (diabetes duration, A1C, systolic blood pressure, waist-to-hip ratio, and use of diabetes medications), fibrinogen (odds ratio 1.14 [95% CI 1.01–1.32], P 0.05) and PAP (1.25 [1.05–1.50], P0.01) were associated with any diabetic retinopathy, while PAP (1.54 [1.13–2.11], P 0.007) and homocysteine (1.57 [1.16– 2.11], P 0.003) were associated with vision-threatening diabetic retinopathy. Only PAP remained significant after additional adjustment for serum creatinine and UAC ratio. Area under receiver-operator characteristic curve (AUROC) for diabetic retinopathy was constructed for established and novel risk factors. Established risk factors accounted for a 39.2% increase of the AUROC, whereas novel markers (fibrinogen, PAP, homocysteine, serum creatinine, and UAC ratio) only accounted for an additional 2.2%. Conclusions— There were few associations of novel markers of inflammation, hemostasis, and homocysteine with diabetic retinopathy after controlling for established risk factors. These data suggest that there is limited clinical use of these biomarkers for prediction of diabetic retinopathy

Alterations in Retinal Microvascular Geometry in Young Type 1 Diabetes

OBJECTIVE - To describe retinal microvascular geometric parameters in young patients with type 1 diabetes. RESEARCH DESIGN AND METHODS - Patients with type 1 diabetes (aged 12-20 years) had clinical assessments and retinal photography following standardized protocol at a tertiary-care hospital in Sydney. Retinal microvascular geometry, including arteriolar and venular tortuosity, branching angles, optimality deviation, and length-to-diameter ratio (LDR), were measured from digitized photographs. Associations of these geometric characteristics with diabetes duration, A1C level, systolic blood pressure (SBP), and other risk factors were assessed. RESULTS - Of 1,159 patients enrolled, 944 (81.4%) had gradable photographs and 170 (14.7%) had retinopathy. Older age was associated with decreased arteriolar (P = 0.024) and venular (P = 0.002) tortuosity, and female subjects had larger arteriolar branching angle than male subjects (P = 0.03). After adjusting for age and sex, longer diabetes duration was associated with larger arteriolar branching angle (P ≤ 0.001) and increased arteriolar optimality deviation (P = 0.018), higher A1C was associated with increased arteriolar tortuosity (>8.5 vs. ≤8.5%, P = 0.008), higher SBP was associated with decreased arteriolar LDR (P = 0.002), and higher total cholesterol levels were associated with increased arteriolar LDR (P = 0.044) and decreased venular optimality deviation (P = 0.044). These associations remained after controlling for A1C, retinal vessel caliber, and retinopathy status and were seen in subjects without retinopathy. CONCLUSIONS - Key diabetes-related factors affect retinal microvascular geometry in young type 1 diabetes, even in those without evidence of retinopathy. These early retinal alterations may be markers of diabetes microvascular complications. © 2010 by the American Diabetes Association.link_to_OA_fulltex