Are we testing visual acuity adequately?

Visual field testing has benefited from advances in computerised technology and is considered highly accurate and reliable, whereas visual acuity testing still relies on the examiner to apply their best judgement. Is it time to reconsider

International multi-center study of iatrogenic retinal tears in pars plana vitrectomy

AIM: To study and compare the effect of different surgical settings on the development of iatrogenic retinal tears (IRT) in conventional (20-gauge) and microincisional vitrectomy. METHODS: An international retrospective comparative study of 394 patients who had simple vitrectomy at three tertiary centers. Surgeries were performed by four retina surgeons using different viewing systems. Two groups of eyes were compared: microincisional vitrectomy (327 eyes) and conventional (67 eyes) vitrectomy. An iatrogenic tear was defined as the occurrence of one or more peripheral retinal tears during surgery or at any visit in the first 6wk postoperatively. RESULTS: Mean age was 67+/-12y and 55% were female. Iatrogenic tears occurred in 11/394 (2.8%) of eyes. The rate of tears was similar among different surgeons and viewing systems (P=0.93 and P=0.76, respectively). Surgical indication, preexisting pseudophakia/aphakia, induction of posterior vitreous detachment (PVD) during surgery, and the use triamcinolone acetonide didn\u27t significantly affect the rate of tears (P \u3e 0.1 for all factors). A higher rate of tears was found in the conventional group compared to the microincisional group (respectively, 7.5%, 1.8%, P=0.02). CONCLUSION: The rate of IRT in vitrectomy is not significantly affected by surgical indication, preexisting PVD or pseudophakia, or use of triamcinolone or different viewing systems but is significantly higher in conventional vitrectomy. Microincisional platforms improve the safety of vitrectomy regardless of the viewing system used

Development in Astronomy and Space Science in Africa

The development of astronomy and space science in Africa has grown significantly over the past few years. These advancements make the United Nations Sustainable Development Goals more achievable, and open up the possibility of new beneficial collaborations.Comment: Paper published in Nature Astronomy. Figures 1 and 2 are included in the published version, that can be seen at https://rdcu.be/2oE

Повторные измерения толщины слоя нервных волокон с помощью оптического когерентного томографа Stratus

PURPOSE: Assessment of optic disc damage is an essential part of the ocular examination and differential diagnosis between the patient with ocular hypertension and pre-perimetric or perimetric glaucoma. The Stratus optic coherent tomograph (Carl Zeiss Meditec, Inc, Dublin, Calif) is still one of the most used optic nerve imaging technology throughout the world. Therefore, the development of methodology that enhances the utility of optic disc measurements with the Stratus OCT remains a relevant and meaningful goal. In an attempt to determine the optimal number of repeated measurements we investigated how the average of three sets of manually repeated measurements of retina nerve firer layer (RNFL) thickness would compare with a single set. METHODS: A total of 73 individuals (136 eyes) aged 55.3±15.2 years with ocular hypertensive (OHT), pre-peri-metric glaucoma or glaucoma were included in the final analysis. When the data was evaluated using a quadrant analysis we observed that 13.6% of the patients exhibited a clinically meaningful difference of 20% or more in the serial RNFL thickness measurements. RESULTS: The difference ranged from 9.3 to 32.7 microns and in 10 of the 12 quadrants the averaged measurement exceeded the initial measurement. Most of the differences demonstrated in this study occurred in the horizontal meridian and are probably a result of instinctive saccadic eye movements. A difference in the vertical meridian (superior and/or inferior quadrants) which is the more relevant meridian for changes in glaucoma was seen in only 3 patients (4.1%). CONCLUSIONS: One reliable RNFL measurement would be sufficient in most of these cases because in 95.9% of the cases the differences observed for the vertical meridian were less than 20%. Nevertheless, it is important to recognize that there can be more variability in the horizontal meridian and that in cases with visual loss encroaching on fixation serial measurements may be useful. At any rate, as with all ancillary tests, whenever a change is detected, it is wise to repeat the test to verify the results.ЦЕЛЬ. Оценка изменений в диске зрительного нерва является важной частью офтальмологического обследования и дифференциальной диагностики у пациентов с офтальмогипертензией и ранней и развитой стадиями глаукомы. Оптический когерентный томограф Stratus (Carl Zeiss Meditec, Inc, Dublin, Calif) до сих пор является одним из самых часто используемых приборов для визуализации зрительного нерва по всему миру. Поэтому разработка методологии, оптимизирующей оценку состояния диска зрительного нерва с помощью Stratus, остается важной и актуальной задачей. В попытке определить оптимальное количество последовательных измерений, мы сравнивали результаты одиночного измерения толщины слоя нервных волокон с усредненными результатами серии из трех последовательных измерений. методы. Всего в исследовании участвовало 73 пациента (136 глаз) в возрасте 55,3±15,2 года с офтальмогипертензией или диагностированной глаукомой. При анализе полученных данных по квадрантам поля зрения у 13,6% пациентов было обнаружено клинически значимое различие ≥ 20% в толщине слоя нервных волокон. РЕЗУЛЬТАТЫ. Разница в измерениях составляла от 9,3 до 32,7 мкм, и в 10 из 12 квадрантов усредненный результат трех последовательных измерений превышал результат единичного измерения. В большинстве случав различие отмечалось в горизонтальном меридиане и, вероятно, являлось результатом естественных саккадных движений. Различие в результатах по более значимому для изменений поля зрения при глаукоме вертикальному меридиану (верхние и/или нижние квадранты) наблюдалось только у 3 (4,1%) пациентов. ЗАКЛЮЧЕНИЕ. Поскольку в 95,9% случаев разница результатов по вертикальному меридиану не превышает 20%, можно сделать вывод, что в большинстве случаев достаточно одного достоверного измерения толщины слоя нервных волокон сетчатки. Тем не менее полезно помнить о большей вариабельности результатов по горизонтальному меридиану. Например, в случае со снижением зрения, затрудняющим фиксацию взгляда, может быть полезным проведение серии из нескольких исследований подряд. В любом случае при появлении изменений в результатах этого или других вспомогательных исследований наилучшей тактикой является повторение исследования для подтверждения результатов

Multiphase turbulence in bubbly flows: RANS simulations

The ability of a two-fluid Eulerian–Eulerian computational multiphase fluid dynamic model to predict bubbly air–water flows is studied. Upward and downward pipe flows are considered and a database of 19 experiments from 6 different literature sources is used to assess the accuracy of the model, with the aim of evaluating our ability to predict these kinds of flows and to contribute to ongoing efforts to develop more advanced simulation tools. The particular focus in the work described is on the prediction of multiphase turbulence due to its relevance in the modelling of bubbly flows in general, including bubble coalescence and break-up, and boiling at a wall. Overall, a satisfactory accuracy is obtained in the prediction of liquid velocities and void fraction distributions in all conditions, including upward and downward flows, and wall-peaked and core-peaked void profiles, when values of the bubble diameter are specified from experimental data. Due to its importance for the correct prediction of the turbulence level in these flows, a bubble-induced turbulence model is introduced, starting from an existing formulation. Source terms due to drag are included in the turbulence kinetic energy and the turbulence energy dissipation rate equations of the k-ε turbulence model, and optimisation of the turbulence source gives velocity fluctuation predictions in agreement with data. After comparisons with data, improvement in the predictions of other turbulence models is also demonstrated, with a Reynolds stress formulation based on the SSG (Speziale et al., 1991) pressure–strain model and the same bubble-induced turbulence model accurately predicting the two-phase flows and the anisotropy of the turbulence field. The same database is also exploited to evaluate different drag models and the advantages of including the effect of the bubble aspect ratio. Following experimental evidence, the model of Tomiyama et al. (2002) is used which assumes that the bubble shape is closer to spherical near a wall and employs a correlation to calculate the aspect ratio. An increase in the drag coefficient due to the higher aspect ratio increases the accuracy of calculated velocity profiles in the near-wall region, even if additional validation is still required due to the possible loss of accuracy in the pipe centre

Novel homozygous missense mutation in GAN associated with Charcot-Marie-Tooth disease type 2 in a large consanguineous family from Israel.

BACKGROUND: CMT-2 is a clinically and genetically heterogeneous group of peripheral axonal neuropathies characterized by slowly progressive weakness and atrophy of distal limb muscles resulting from length-dependent motor and sensory neurodegeneration. Classical giant axonal neuropathy (GAN) is an autosomal recessively inherited progressive neurodegenerative disorder of the peripheral and central nervous systems, typically diagnosed in early childhood and resulting in death by the end of the third decade. Distinctive phenotypic features are the presence of "kinky" hair and long eyelashes. The genetic basis of the disease has been well established, with over 40 associated mutations identified in the gene GAN, encoding the BTB-KELCH protein gigaxonin, involved in intermediate filament regulation. METHODS: An Illumina Human CytoSNP-12 array followed by whole exome sequence analysis was used to identify the disease associated gene mutation in a large consanguineous family diagnosed with Charcot-Marie-Tooth disease type 2 (CMT-2) from which all but one affected member had straight hair. RESULTS: Here we report the identification of a novel GAN missense mutation underlying the CMT-2 phenotype observed in this family. Although milder forms of GAN, with and without the presence of kinky hair have been reported previously, a phenotype distinct from that was investigated in this study. All family members lacked common features of GAN, including ataxia, nystagmus, intellectual disability, seizures, and central nervous system involvement. CONCLUSIONS: Our findings broaden the spectrum of phenotypes associated with GAN mutations and emphasize a need to proceed with caution when providing families with diagnostic or prognostic information based on either clinical or genetic findings alone

Influence of multiphase turbulence modelling on interfacial momentum transfer in two-fluid Eulerian-Eulerian CFD models of bubbly flows

Eulerian-Eulerian two-fluid computational fluid dynamic (CFD) models are increasingly used to predict bubbly flows at an industrial scale. In these approaches, interface transfer is modelled with closure models and correlations. Normally, the lateral void fraction distribution is considered to mainly result from a balance between the lift and wall lubrication forces. However, and despite the numerous models available that achieve, at least in pipe flows, a reasonable predictive accuracy, agreement on a broadly applicable and accurate modelling approach has not yet been reached. Additionally, the impact of turbulence modelling on the lateral void fraction distribution has not, in general, been examined in detail. In this work, an elliptic blending Reynolds stress model (EB-RSM), capable of resolving the turbulence field in the near-wall region and improved to account for the contribution of bubble-induced turbulence, is evaluated against best-practice k-ε and high-Reynolds second-moment turbulence closures. Lift and wall lubrication forces are initially deliberately neglected in the EB-RSM. Comparisons for flows in pipes and a square duct show that the EB-RSM reproduces the lateral void fraction distribution, including the peak in the void fraction in the near-wall region, and reaches an accuracy comparable to the other two models noted above. In rod bundles, even if none of the models considered performs with sufficient accuracy, the EB-RSM detects features of the flow that are not predicted by the other two approaches. Overall, the results demonstrate a much more prominent role of the turbulence structure and the induced cross-sectional pressure field on the lateral void fraction distribution than is normally considered. These effects need to be accounted for if more physically-consistent modelling of bubbly flows is to be achieved. The lift force is added to the EB-RSM in the final part of the paper, to provide a two-fluid formulation that can be used as the basis for additional developments aimed at improving the accuracy and general applicability of two-fluid CFD models

National identity predicts public health support during a global pandemic.

Changing collective behaviour and supporting non-pharmaceutical interventions is an important component in mitigating virus transmission during a pandemic. In a large international collaboration (Study 1, N = 49,968 across 67 countries), we investigated self-reported factors associated with public health behaviours (e.g., spatial distancing and stricter hygiene) and endorsed public policy interventions (e.g., closing bars and restaurants) during the early stage of the COVID-19 pandemic (April-May 2020). Respondents who reported identifying more strongly with their nation consistently reported greater engagement in public health behaviours and support for public health policies. Results were similar for representative and non-representative national samples. Study 2 (N = 42 countries) conceptually replicated the central finding using aggregate indices of national identity (obtained using the World Values Survey) and a measure of actual behaviour change during the pandemic (obtained from Google mobility reports). Higher levels of national identification prior to the pandemic predicted lower mobility during the early stage of the pandemic (r = -0.40). We discuss the potential implications of links between national identity, leadership, and public health for managing COVID-19 and future pandemics

National identity predicts public health support during a global pandemic (vol 13, 517, 2022) : National identity predicts public health support during a global pandemic (Nature Communications, (2022), 13, 1, (517), 10.1038/s41467-021-27668-9)

Publisher Copyright: © The Author(s) 2022.In this article the author name ‘Agustin Ibanez’ was incorrectly written as ‘Augustin Ibanez’. The original article has been corrected.Peer reviewe