Effects of low visual acuity on neuropsychological test scores:A simulation study

Objective: To systematically examine the effect of low visual acuity (LVA) on a number of commonly used neuropsychological tests. Method: In this study, the influence of LVA on a number of commonly used neuropsychological tests was examined in 238 healthy older adults (aged 50–80) without visual or neurological impairment. LVA was simulated using simulation glasses. Results: It was found that a simulated LVA of ∼0.2 (decimal acuity; Snellen 6/30 or 20/100, LogMAR 0.7) had a negative impact on test performance for the Trail Making Test, Complex Figure of Rey (copy score), and Visual Object and Space Perception battery subtest 3, but not for the Mini Mental State Examination and Balloons test. For some tests, the negative impact of LVA increased with age. Conclusions: These results have important implications for the use of neuropsychological tests in the visually impaired population. More specifically, when administering the Trail Making Test, Complex Figure of Rey (copy score), and Visual Object and Space Perception Battery subtest 3 to older people with LVA, low test scores should be interpreted with great caution. Low test scores on the Mini Mental State Examination and Balloons Test are not likely to be caused by LVA and are more likely to reflect actual cognitive impairment. The results contribute to the validity of neuropsychological assessment of older people with visual impairment, leading to more effective and more patient-based rehabilitation

Ocean Acidification Changes Abiotic Processes but Not Biotic Processes in Coral Reef Sediments

In coral reefs, sediments play a crucial role in element cycling by contributing to primary production and the remineralization of organic matter. We studied how future ocean acidification (OA) will affect biotic and abiotic processes in sediments from two coral reefs of the Great Barrier Reef, Australia. This was investigated in the laboratory under conditions where water-sediment exchange was dominated by molecular diffusion (Magnetic Island) or by porewater advection (Davies Reef). OA conditions (+ΔpCO2: 170–900 μatm, −ΔpH: 0.1–0.4) did not affect photosynthesis, aerobic and anaerobic organic matter remineralization, and growth of microphytobenthos. However, microsensor measurements showed that OA conditions reduced the porewater pH. Under diffusive conditions these changes were limited to the upper sediment layers. In contrast, advective conditions caused a deeper penetration of low pH water into the sediment resulting in an earlier pH buffering by dissolution of calcium carbonate (CaCO3). This increased the dissolution of Davis Reef sediments turning them from net precipitating (−0.8 g CaCO3 m−2 d−1) under ambient to net dissolving (1 g CaCO3 m−2 d−1) under OA conditions. Comparisons with in-situ studies on other reef sediments show that our dissolution rates are reasonable estimates for field settings. We estimate that enhanced dissolution due to OA will only have a minor effect on net ecosystem calcification of the Davies Reef flat (<4%). However, it could decrease recent sediment accumulation rates in the lagoon by up to 31% (by 0.2–0.4 mm year−1), reducing valuable reef space. Furthermore, our results indicate that high-magnesium calcite is predominantly dissolving in the studied sediments and a drastic reduction in this mineral can be expected on Davis Reef lagoon in the near future, leaving sediments of an altered mineral composition. This study demonstrates that biotic sediment processes will likely not directly be affected by OA. Ensuing indirect effects of OA-induced sediment dissolution on biotic processes are discussed

Derivatives. Replication and (auto)plagiarism in the social sciences

This working paper reports on the travelling exhibition “Derivatives”. This exhibition investigates the issue of originality in the context of (self) plagiarism and replication. The different views in the Arts and the scientific discourse form the point of departure for discovering how ideas that are identical can still be completely different and new, but also that ‘original’ works of art can be repetitive reproduction