481 research outputs found
Digitale prøver – et litteraturstudie
Digitale prøveformer bliver efterhånden mere og mere udbredte. Denne artikel er baseret på et litteraturstudie foretaget for at få indsigt i primært forskningslitteraturen om digitale prøveformer. I artiklen præsenterer vi de forskellige typer digitale prøver, der omtales og diskuteres i litteraturen, og vi beskriver de potentielle fordele af bl.a. økonomisk, administrativ og pædagogisk karakter, der ifølge litteraturen kan opnås ved at bruge digitale prøver. Vi beskriver endvidere de udfordringer og potentielle ulemper, der kan være forbundet med indførelse af digitale prøver. Det drejer sig bl.a. om udfordringer hvad angår prøvesystem, organisation, teknologi, kompetenceudvikling og uddannelseskultur. Vi beskriver i artiklen en række konkrete eksempler på digitale prøver, og vi præsenterer resultater fra undersøgelser af underviseres og studerendes oplevelser med digitale prøveformer.
Against the backdrop of the rapid spread of digitized tests and exams, this article sets out to present some of the results of a literature study carried out with the aim of gaining insight into the research literature on this topic. The article presents different types of tests, focusing on the financial, administrative, and pedagogical advantages described and discussed in the literature as potentially attainable through the use of digitized exams. In addition, the challenges and potential problems connected with the introduction of digitized tests are described. Among these are challenges related to the test system or to competence development as well as organizational, technological, and cultural challenges. Finally, the article provides concrete descriptions of tests and presents results from select studies of teacher and student experiences of digitized tests
Analysis of Functional Differences between Hepatitis C Virus NS5A of Genotypes 1–7 in Infectious Cell Culture Systems
Hepatitis C virus (HCV) is an important cause of chronic liver disease. Several highly diverse HCV genotypes exist with potential key functional differences. The HCV NS5A protein was associated with response to interferon (IFN)-α based therapy, and is a primary target of currently developed directly-acting antiviral compounds. NS5A is important for replication and virus production, but has not been studied for most HCV genotypes. We studied the function of NS5A using infectious NS5A genotype 1–7 cell culture systems, and through reverse genetics demonstrated a universal importance of the amphipathic alpha-helix, domain I and II and the low-complexity sequence (LCS) I for HCV replication; the replicon-enhancing LCSI mutation S225P attenuated all genotypes. Mutation of conserved prolines in LCSII led to minor reductions in virus production for the JFH1(genotype 2a) NS5A recombinant, but had greater effects on other isolates; replication was highly attenuated for ED43(4a) and QC69(7a) recombinants. Deletion of the conserved residues 414-428 in domain III reduced virus production for most recombinants but not JFH1(2a). Reduced virus production was linked to attenuated replication in all cases, but ED43(4a) and SA13(5a) also displayed impaired particle assembly. Compared to the original H77C(1a) NS5A recombinant, the changes in LCSII and domain III reduced the amounts of NS5A present. For H77C(1a) and TN(1a) NS5A recombinants, we observed a genetic linkage between NS5A and p7, since introduced changes in NS5A led to changes in p7 and vice versa. Finally, NS5A function depended on genotype-specific residues in domain I, as changing genotype 2a-specific residues to genotype 1a sequence and vice versa led to highly attenuated mutants. In conclusion, this study identified NS5A genetic elements essential for all major HCV genotypes in infectious cell culture systems. Genotype- or isolate- specific NS5A functional differences were identified, which will be important for understanding of HCV NS5A function and therapeutic targeting
Theoretical investigation of carbon defects and diffusion in α-quartz
The geometries, formation energies, and diffusion barriers of carbon point defects in silica (α-quartz) have been calculated using a charge-self-consistent density-functional based nonorthogonal tight-binding method. It is found that bonded interstitial carbon configurations have significantly lower formation energies (on the order of 5 eV) than substitutionals. The activation energy of atomic C diffusion via trapping and detrapping in interstitial positions is about 2.7 eV. Extraction of a CO molecule requires an activation energy <3.1 eV but the CO molecule can diffuse with an activation energy <0.4 eV. Retrapping in oxygen vacancies is hindered—unlike for O2—by a barrier of about 2 eV
Epidemiology of Hyperhidrosis in Danish Blood Donors
The risk factors and disease implications of hyperhidrosis are unknown. The objectives of this retrospective cohort study were to estimate the prevalence of hyperhidrosis and to compare demographic, lifestyle, and socioeconomic parameters in blood donors with and without self-reported or hospital-diagnosed hyperhidrosis. The study included blood donors from the Danish Blood Donor Study for the period 2010–2019. Registry data were collected from Statistics Denmark. Overall, 2,794 of 30,808 blood donors (9.07%; 95% confidence interval (95% CI) 8.75–9.40) had self-reported hyperhidrosis and 284 of 122,225 (0.23%; 95% CI 0.21–0.26) had hospital-diagnosed hyperhidrosis. Self-reported hyperhidrosis was associated with smoking (odds ratio (OR) 1.17; 95% CI 1.05– 1.31), overweight (OR 1.72; 95% CI 1.58–1.87), “unemployed” (OR 1.60; 95% CI 1.24–2.08), “short education” (OR 0.76; 95% CI 0.64–0.90), and lower income (beta-coefficient –26,121; 95% CI –37,931, –14,311). Hospital-diagnosed hyperhidrosis did not differ from controls. Thus, self-reported hyperhidrosis was associated with potential hyperhidrosis risk factors (smoking, overweight) and disease implications (unemployment, low education level and income)
Correlates, determinants, and effectiveness of childcare educators’ practices and behaviours on preschoolers’ physical activity and eating behaviours: a systematic review protocol
Abstract: Background: Worldwide, approximately 12% of children under the age of 5 are either overweight or obese. As many young children spend 30 h or more per week in childcare centres with childcare educators. Targeting childcare educators as role models may prove an effective strategy for the promotion of healthy eating and physical activity. This manuscript describes the methods to systematically review existing literature relating to how childcare educators influence children’s healthy eating and physical activity behaviours, as well as the links between specific practices and behaviours of childcare educators and children’s healthy lifestyle behaviours. Methods: Relevant peer-reviewed studies will be identified through a computerized literature search in six databases: PubMed, The Cochrane Library, Science Direct, CINAHL, Wiley and SportDiscus. Quantitative studies written in English or French reporting the correlates, predictors or effectiveness of childcare educators’ practices and behaviours on preschoolers’ healthy eating and physical activity behaviours will be included. The quality of retained studies will be assessed using the Quality Assessment Tool for Quantitative Studies. Descriptive summary statistics of study characteristics will be reported as well as the study designs and exposure and outcome measures. Inter-rater agreements for study selection and quality assessments will be reported and unadjusted, and adjusted results will be presented. Reporting of the systematic review will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Discussion: This systematic review will contribute to a better understanding of the potential of childcare educators as role models for young children, as well as the influence (or impact) of their behaviours and intervention on children’s short- and long-term health. It will provide important information that could be used to improve obesity prevention strategies and initiatives, as well as to guide the improvement or implementation of effective healthy eating and physical activity policies in childcare centres. Systematic review registration: PROSPERO (CRD42014012973
Correlation ECE diagnostic in Alcator C-Mod
Correlation ECE (CECE) is a diagnostic technique that allows measurement of small amplitude electron temperature, T[subscript e], fluctuations through standard cross-correlation analysis methods. In Alcator C-Mod, a new CECE diagnostic has been installed[Sung RSI 2012], and interesting phenomena have been observed in various plasma conditions. We find that local T[subscript e] fluctuations near the edge (ρ ~ 0:8) decrease across the linearto- saturated ohmic confinement transition, with fluctuations decreasing with increasing plasma density[Sung NF 2013], which occurs simultaneously with rotation reversals[Rice NF 2011]. T[subscript e] fluctuations are also reduced across core rotation reversals with an increase of plasma density in RF heated L-mode plasmas, which implies that the same physics related to the reduction of T[subscript e] fluctuations may be applied to both ohmic and RF heated L-mode plasmas. In I-mode plasmas, we observe the reduction of core T[subscript e] fluctuations, which indicates changes of turbulence occur not only in the pedestal region but also in the core across the L/I transition[White NF 2014]. The present CECE diagnostic system in C-Mod and these experimental results are described in this paper
Nonlinear gyrokinetic simulations of the I-mode high confinement regime and comparisons with experimenta)
For the first time, nonlinear gyrokinetic simulations of I-mode plasmas are performed and compared with experiment. I-mode is a high confinement regime, featuring energy confinement similar to H-mode, but without enhanced particle and impurity particle confinement [D. G. Whyte et al., Nucl. Fusion 50, 105005 (2010)]. As a consequence of the separation between heat and particle transport, I-mode exhibits several favorable characteristics compared to H-mode. The nonlinear gyrokinetic code GYRO [J. Candy and R. E. Waltz, J Comput. Phys. 186, 545 (2003)] is used to explore the effects of E × B shear and profile stiffness in I-mode and compare with L-mode. The nonlinear GYRO simulations show that I-mode core ion temperature and electron temperature profiles are more stiff than L-mode core plasmas. Scans of the input E × B shear in GYRO simulations show that E × B shearing of turbulence is a stronger effect in the core of I-mode than L-mode. The nonlinear simulations match the observed reductions in long wavelength density fluctuation levels across the L-I transition but underestimate the reduction of long wavelength electron temperature fluctuation levels. The comparisons between experiment and gyrokinetic simulations for I-mode suggest that increased E × B shearing of turbulence combined with increased profile stiffness are responsible for the reductions in core turbulence observed in the experiment, and that I-mode resembles H-mode plasmas more than L-mode plasmas with regards to marginal stability and temperature profile stiffness.United States. Department of Energy (Contract No. DE-FC02-99ER54512-CMOD)United States. Department of Energy. Office of Science (Contract No. DE-AC02- 05CH11231
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