Assesseer leesbegripstoetse werklik leesbegrip?

In hierdie artikel word die vraag gestel of leesbegripstoetse, wat volgens onderwysdepartementele voorskrifte opgestel is, werklik leesbegripsvlakke assesseer. Riglyne van die Nasionale Kurrikulum- en Assesseringsbeleidsverklaring (Suid- Afrika, 2011) is gebruik om twee gelyksoortige leesbegripstoetse (drie tekste elk), wat uit dieselfde tekstipes bestaan, maar handel oor verskillende temas, op te stel om Afrikaanssprekende graad 9-leerders, uit verskillende geografiese gebiede van ’n onderwysdistrik, se leesbegripsvlakke te bepaal. Die moeilikheidsgraad van die leestekste is met leesbaarheidsindekse bepaal en ’n 40-40-20%-verspreiding van kognitiewe vlakke is in die vraagstelling gevolg. Bo en behalwe die berekening van gemiddeldes, frekwensies en persentasies is die Cronbach Alphakoëffisiëntwaardes en die gemiddelde interitem-korrelasiewaardes vir elkeen van die drie tekste binne die twee tematies verskillende leesbegripstoetse vasgestel en leesbegripstoetse se vrae is volgens Bloom se kognitiewe vlakke vergelyk. Die hoofbevinding is dat leerders se leesbegripsvlakke nie akkuraat deur tipiese leesbegripstoetse geassesseer word nie, omdat hulle leesbegrippunte in ’n mindere of ’n meerdere mate op verskillende wyses gekontamineer word.Sleutelwoorde: assessering, kognitiewe vlakke, leesbaarheidsindekse, leesbegrip, Nasionale Kurrikulum- en Assesseringsbeleidsverklarin

The spectrum of lower motor neuron syndromes : classification, natural course and treatment

This thesis focusses on patients with lower motor neuron syndromes. This relatively rare group of syndromes is clinically not well described and the pathogenesis is largely unknown. Two subgroups can be distinguished: patients in whom motor neurons (lower motor neuron disease (LMND)) or motor axons and their surrounding myelin (multifocal motor neuropathy (MMN)) are affected, both leading to muscle atrophy and weakness. As MMN is a potentially treatable disorder, its differentiation from LMND is important. Evidence of motor conduction block on nerve conduction studies and a positive response to treatment with intravenous immunoglobulins (IVIg) are considered the most relevant criteria for the diagnosis of MMN. The improvement of the techniques to detect conduction block and new developments in DNA-proven hereditary LMND, have made some of the earlier classi.cations of lower motor neuron syndromes obsolete. Also little is known about the natural course and treatment of lower motor neuron syndromes. Aims The aims of this study were (1) to improve the classi.cation of patients with lower motor neuron syndromes using newest diagnostic methods, (2) to determine the natural course of these syndromes, and (3) to study treatment forms in MMN. Methods Patients were examined clinically at a regular basis, which consisted of the assessment of muscle atrophy and weakness, respiratory function and functional impairment. All patients underwent an extensive, standardized electrophysiological examination at least once. Results Based on the pattern of weakness in 49 patients with LMND, we identi.ed four subgroups. Except for one group with generalized weakness and respiratory insuf.- ciency, leading to death in one third of patients, the disease course in patients with IX LMND was slow, with minimal progression of muscle weakness and functional impairment over years. Also in patients with MMN we found evidence for a slowly progressive disease course. We propose a set of clinical, laboratory and electrophysiological criteria for the diagnosis of MMN, which has been verifed by follow-up and response to IVIg treatment in 37 patients with a lower motor neuron syndrome. Additionally, we studied the distribution of electrophysiological abnormalities in MMN, its correlation with weakness and the development of an optimal electrodiagnostic protocol for MMN. The results of a follow-up study on the efficacy of long-term (4-8 years) maintenance therapy in 11 patients with MMN, showed that IVIg maintenance treatment has a bene.cial long-term effect on muscle strength and upper limb disability, and thus seems rational, but may not prevent a slight decrease in muscle strength. Electrophysiologically, both improvement and worsening were found. In an open pilot-study with interferon-b1a (IFN-b1a, 3x/wk for 6 months) in nine patients with MMN, three patients showed an improvement on IFN-b1a which was more pronounced than on IVIg and which sustained itself for months after discontinuation of IFN-b1a. A controlled study is necessary to further investigate the effect of IFN-b1a treatment in patients with MMN. Conclusions Until we have identi.ed these possible underlying pathophysiological mechanisms it will prove difficult to consider the various lower motor neuron syndromes as separate diseases. Because diagnostic and therapeutic options may differ, it seems rational to consider them as a spectrum of syndromes, which can be distinguished from each other on the basis of the clinical presentation and the electrophysiological findings. For the individual patient distinction between the various syndromes is important as it enables the physician to provide adequate information over the disease course and to facilitate early treatment in MMN

Validation of a spectral light scattering method to differentiate large from small particles in intraocular lenses.

A psychophysical approach has been designed to measure straylight from intraocular lenses (IOLs) in vitro. This approach uses a clinical straylight meter (C-Quant) and an observer's eye as optical detector. Based on this, we introduced a method for study of straylight-wavelength dependency for IOLs. This dependency can be used to distinguish between 2 types of scattering particles (small and large) as defined by Mie theory. Validation was performed using a turbidity standard and scattering filters. Several IOLs were analyzed to identify potential scattering sources. Large particles were found to predominate in scattering from the studied lenses. This was confirmed by straylight-angular dependency found in these IOLs

Understanding disability glare: light scatter and retinal illuminance as predictors of sensitivity to contrast

The presence of a bright light in the visual field has two main effects on the retinal image: reduced contrast and increased retinal illuminance due to scattered light; the latter can, under some conditions, lead to an improvement in retinal sensitivity. The combined effect remains poorly understood, particularly at low light levels. A psychophysical flicker-cancellation test was used to measure the amount and angular distribution of scattered light in the eye for 40 observers. Contrast thresholds were measured using a functional contrast sensitivity test. Pupil-plane glare-source illuminances (i.e. 0, 1.35, 19.21 lm/m2), eccentricities (5°, 10°, 15°), and background luminances (1, 2.6, 26 cd/m2) were investigated. Visual performance was better than predicted, based on loss of retinal image contrast caused by scattered light, particularly in the mesopic range. Prediction accuracy improved significantly when the expected increase in retinal sensitivity in the presence of scattered light was also incorporated in the model

Optical Scattering Measurements of Laser Induced Damage in the Intraocular Lens

This study optically determines whether the amount of light scatter due to laser-induced damage to the intraocular lens (IOL) is significant in relation to normal straylight values in the human eye. Two IOLs with laser-induced damage were extracted from two donor eyes. Each IOL had 15 pits and/or cracks. The surface area of each pit was measured using a microscope. For 6 pits per intraocular lens the point spread function (PSF) in terms of straylight was measured and the total straylight for all 15 pits was estimated. The damage in the IOLs was scored as mild/moderate. The total damaged surface areas, for a 3.5 mm pupil, in the two IOLs were 0.13% (0.0127 mm2) and 0.66% (0.064 mm2), respectively. The angular dependence of the straylight caused by the damage was similar to that of the normal PSF. The total average contribution to straylight was log(s) = −0.82 and −0.42, much less than the straylight value of the normal eye

Revealing methyl-esterification patterns of pectins by enzymatic fingerprinting:Beyond the degree of blockiness

Citrus pectins were studied by enzymatic fingerprinting using a simultaneous enzyme treatment with endo-polygalacturonase (endo-PG) from Kluyveromyces fragilis and pectin lyase (PL) from Aspergillus niger to reveal the methyl-ester distribution patterns over the pectin backbone. Using HILIC-MS combined with HPAEC enabled the separation and identification of the diagnostic oligomers released. Structural information on the pectins was provided by using novel descriptive parameters such as degree of blockiness of methyl-esterified oligomers by PG (DBPGme) and degree of blockiness of methyl-esterified oligomers by PL (DBPLme). This approach enabled us to clearly differentiate citrus pectins with various methyl-esterification patterns. The simultaneous use of PG and PL showed additional information, which is not revealed in digests using PG or PL alone. This approach can be valuable to differentiate pectins having the same DM and to get specific structural information on pectins and therefore to be able to better predict their physical and biochemical functionalities

Immunological Adaptations to Pregnancy in Women with Type 1 Diabetes

Despite adequate glycemic control, pregnancy outcome of women with type 1 diabetes (T1D) is still unfavorable as compared to healthy women. In a rat-model of T1D under normoglycemic conditions, adverse pregnancy outcome was also observed, which was associated with aberrant immunological adaptations to pregnancy. Because similar processes may occur in women with T1D we studied the systemic immune response in non-pregnant and pregnant women with and without T1D. The systemic immune response was assessed by using flow cytometry to evaluate the number and activational status of subpopulations of lymphocytes, Natural Killer cells and monocytes in peripheral blood of non-pregnant and pregnant women with and without T1D. An increased white blood cell count, an increased Th1/Th2 ratio, increased Natural Killer cell expression of CD335 and enhanced activation of intermediate and non-classical monocytes was observed in pregnant women with T1D vs. healthy pregnant women. Also, the pregnancy outcome (i.e. incidence of preterm delivery and macrosomia) of women with T1D was unfavorable as compared to healthy women. This study showed that in T1D, the immunological adaptations to pregnancy are disturbed. In addition to hyperglycemia, these different immunological adaptations may be responsible for the greater frequency of complications in pregnant women with T1D