Eye-brain interactions in the development and maintenance of the Drosophila visual system

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Biology, 1994.Includes bibliographical references.by Margaret L. Winberg.Ph.D

Predicting formative feedback practices: improving learning and minimising a tendency to ignore feedback

IntroductionTeacher conceptions of feedback ideally predict their feedback practices, but little robust evidence identifies which beliefs matter to practices. It is logical to presume that teacher conceptions of feedback would align with the policy framework of an educational jurisdiction. The Teacher Conceptions of Feedback (TCoF) inventory was developed in New Zealand which has a relatively low-stakes, formative policy framework.MethodsThis study surveyed 451 Swedish teachers working in Years 1-9, a policy context that prioritises teachers using multiple data sources to help students learn. The study used a translated version of the TCoF inventory, but isolated six items related to formative feedback practices from various factors.ResultsA six-factor TCoF was recovered (Praise, Improvement, Ignore, Required, PASA, and Timely), giving partial replication to the previous study. A well-fitting structural equation model showed formative practices were predicted by just two conceptions of feedback (i.e., feedback improves learning and students may ignore feedback).DiscussionThis study demonstrates that the TCoF inventory can be used to identify plausible relations from feedback beliefs to formative feedback practices

Plexin A Is a Neuronal Semaphorin Receptor that Controls Axon Guidance

AbstractThe Semaphorins comprise a large family of secreted and transmembrane proteins, some of which function as repellents during axon guidance. Semaphorins fall into seven subclasses. Neuropilins are neuronal receptors for class III Semaphorins. In the immune system, VESPR, a member of the Plexin family, is a receptor for a viral-encoded Semaphorin. Here, we identify two Drosophila Plexins, both of which are expressed in the developing nervous system. We present evidence that Plexin A is a neuronal receptor for class I Semaphorins (Sema 1a and Sema 1b) and show that Plexin A controls motor and CNS axon guidance. Plexins, which themselves contain complete Semaphorin domains, may be both the ancestors of classical Semaphorins and binding partners for Semaphorins

Proteases in Plasma and Kidney of db/db Mice as Markers of Diabetes-Induced Nephropathy

Db/db mice are overweight, dyslipidemic and develop diabetic complications, relevant for similar complications in human type 2 diabetes. We have used db/db and db/+ control mice to investigate alterations in proteinase expression and activity in circulation and kidneys by SDS-PAGE zymography, electron microscopy, immunohistochemistry, Western blotting, and in situ zymography. Plasma from db/db mice contained larger amounts of serine proteinases compared to db/+ mice. Kidneys from the db/db mice had a significantly larger glomerular surface area and somewhat thicker glomerular basement membranes compared to the db/+ mice. Furthermore, kidney extracts from db/+ mice contained metalloproteinases with Mr of approximately 92000, compatible with MMP-9, not observed in db/db mice. These results indicate that higher levels of serine proteinases in plasma may serve as potential markers for kidney changes in db/db mice, whereas a decrease in MMP-9 in the kidney may be related to the glomerular changes

Effect of acute copper sulfate exposure on olfactory responses to amino acids and pheromones in goldfish (Carassius auratus)

Exposure of olfactory epithelium to environmentally relevant concentrations of copper disrupts olfaction in fish. To examine the dynamics of recovery at both functional and morphological levels after acute copper exposure, unilateral exposure of goldfish olfactory epithelia to 100 μM CuSO4 (10 min) was followed by electro-olfactogram (EOG) recording and scanning electron microscopy. Sensitivity to amino acids (L-arginine and L-serine), generally considered food-related odorants, recovered most rapidly (three days), followed by that to catecholamines(3-O-methoxytyramine),bileacids(taurolithocholic acid) and the steroid pheromone, 17,20 -dihydroxy-4-pregnen- 3-one 20-sulfate, which took 28 days to reach full recovery. Sensitivity to the postovulatory pheromone prostaglandin F2R had not fully recovered even at 28 days. These changes in sensitivity were correlated with changes in the recovery of ciliated and microvillous receptor cell types. Microvillous cells appeared largely unaffected by CuSO4 treatment. Cilia in ciliated receptor neurones, however, appeared damaged one day post-treatment and were virtually absent after three days but had begun to recover after 14 days. Together, these results support the hypothesis that microvillous receptor neurones detect amino acids whereas ciliated receptor neurones were not functional and are responsible for detection of social stimuli (bile acidsandpheromones).Furthermore, differences in sensitivity to copper may be due to different transduction pathways in the different cell types

’We do not have a writing culture’: exploring the nature of ‘academic drift’ through a study of lecturer perspectives on student writing in a vocational university

Vocational universities are increasingly becoming susceptible to pressures associated with the phenomenon known as ‘academic drift’. Yet the specific influence of such pressures is experienced differently at various institutional levels and by different stakeholders in such universities. Exploring lecturers’ understanding and perceptions of student academic writing can make visible the ways in which these pressures are realised, for example, in the types of writing given value and writing pedagogies deemed suitable in the context of the vocational university. In this paper, we report on an ethnographically shaped study exploring lecturers’ writing pedagogies and perceptions of students as academic writers at a South African vocational university. The study analytically illustrated how wider socio-political, regulatory and ideological framings of these universities were implicated in lecturers’ writing practices and pedagogies. The study found that lecturers and students were generally constricted by narrow vocationalist agendas, which reinforced negative conceptions of students as academic writers. Our findings suggest that while the explicit impact of academic drift drivers was minimally felt at the undergraduate diploma level of study in our research site, this appeared to close off the potential for writing to act as a means to facilitate students’ epistemic access to their disciplines

Incidence rates and management of urinary tract infections among children in Dutch general practice: results from a nation-wide registration study

BACKGROUND: We aimed to investigate incidence rates of urinary tract infections in Dutch general practice and their association with gender, season and urbanisation level, and to analyse prescription and referral in case of urinary tract infections. METHOD: During one calendar year, 195 general practitioners in 104 practices in the Netherlands registered all their patient contacts. This study was performed by the Netherlands Institute for Health Services Research (NIVEL) in 2001. Of 82,053 children aged 0 to 18 years, the following variables were collected: number of episodes per patient, number of contacts per episode, month of the year in which the diagnosis of urinary tract infection was made, age, gender, urbanisation level, drug prescription and referral. RESULTS: The overall incidence rate was 19 episodes per 1000 person years. The incidence rate in girls was 8 times as high as in boys. The incidence rate in smaller cities and rural areas was 2 times as high as in the three largest cities. Throughout the year, incidence rates varied with a decrease in summertime for children at the age of 0 to 12 years. Of the prescriptions, 66% were in accordance with current guidelines, but only 18% of the children who had an indication were actually referred. CONCLUSION: This study shows that incidence rates of urinary tract infections are not only related to gender and season, but also to urbanisation. General practitioners in the Netherlands frequently do not follow the clinical guidelines for urinary tract infections, especially with respect to referral

Further investigation of confirmed urinary tract infection (UTI) in children under five years: a systematic review.

Background: Further investigation of confirmed UTI in children aims to prevent renal scarring and future complications. Methods: We conducted a systematic review to determine the most effective approach to the further investigation of confirmed urinary tract infection (UTI) in children under five years of age. Results: 73 studies were included. Many studies had methodological limitations or were poorly reported. Effectiveness of further investigations: One study found that routine imaging did not lead to a reduction in recurrent UTIs or renal scarring. Diagnostic accuracy: The studies do not support the use of less invasive tests such as ultrasound as an alternative to renal scintigraphy, either to rule out infection of the upper urinary tract (LR- = 0.57, 95%CI: 0.47, 0.68) and thus to exclude patients from further investigation or to detect renal scarring (LR+ = 3.5, 95% CI: 2.5, 4.8). None of the tests investigated can accurately predict the development of renal scarring. The available evidence supports the consideration of contrast-enhanced ultrasound techniques for detecting vesico-ureteric reflux (VUR), as an alternative to micturating cystourethrography (MCUG) (LR+ = 14.1, 95% CI: 9.5, 20.8; LR- = 0.20, 95%CI: 0.13, 0.29); these techniques have the advantage of not requiring exposure to ionising radiation. Conclusion: There is no evidence to support the clinical effectiveness of routine investigation of children with confirmed UTI. Primary research on the effectiveness, in terms of improved patient outcome, of testing at all stages in the investigation of confirmed urinary tract infection is urgently required