Soft Lenses

A series of cases fitted with Bionite soft lenses is described. Good results were obtained in bullous keratopathy, dry eyes, early and moderately advanced Stevens-Johnson syndrome and pemphigoid, and some cases of indolent corneal ulcers. The lenses appear to be a most effective replacement for tarsorrhaphy, haptic lenses and epikeratoprostheses.S. Afr. Med. J, 47, 148 (1973

The structural and dynamic responses of Stange Ice Shelf to recent environmental change

Stange Ice Shelf is the most south-westerly ice shelf on the Antarctic Peninsula, a region where positive trends in atmospheric and oceanic temperatures have been recently documented. In this paper, we use a range of remotely sensed datasets to evaluate the structural and dynamic responses of Stange Ice Shelf to these environmental changes. Ice shelf extent and surface structures were examined at regular intervals from optical and radar satellite imagery between 1973 and 2011. Surface speeds were estimated in 1989, 2004 and 2010 by tracking surface features in successive satellite images. Surface elevation change was estimated using radar altimetry data acquired between 1992 and 2008 by the European Remote Sensing Satellite (ERS) -1, -2 and Envisat. The mean number of surface melt days was estimated using the intensity of backscatter from Envisat’s Advanced Synthetic Aperture Radar instrument between 2006 and 2012. These results show significant shear fracturing in the southern portion of the ice shelf linked to enhanced flow speed as a consequence of measured thinning. However, we conclude that, despite the observed changes, Stange Ice Shelf is currently stable

Electronic nicotine delivery devices, and their impact on health and patterns of tobacco use: a systematic review protocol

Introduction E-cigarettes or electronic nicotine delivery systems (ENDS) have recently attracted considerable attention. Among some individuals there is strong debate and a polarisation of views about the public health benefits versus harms of ENDS. With little regulation, the ENDS market is evolving, and new products are introduced and marketed constantly. Rapid developments in manufacturing, marketing and consumer domains related to ENDS will warrant frequent re-evaluation, based on the state of the evolving science. The purpose of this article is to describe a protocol for an ongoing comprehensive review of the published scientific literature on ENDS. Methods and analysis We will undertake a systematic review of published empirical research literature on ENDS using the National Library of Medicine\u27s PubMed electronic database to search for relevant articles. Data from included studies will be extracted into a standardised form, tables with study details and key outcomes for each article will be created, and studies will be synthesised qualitatively. Ethics and dissemination This review synthesises published literature and presents no primary data. Therefore, no ethical approval is required for this study. Subsequent papers will provide greater detail on results, within select categories, that represent gaps in the literature base

The 2015 Chileno Valley glacial lake outburst flood, Patagonia

Glacial Lake Outburst Floods (GLOFs) have become increasingly common over the past century in response to climate change, posing risks for human activities in many mountain regions. In this paper we document and reconstruct the sequence of events and impact of a large GLOF that took place in December 2015 in the Chileno Valley, Patagonia. Hydrograph data suggests that the flood continued for around eight days with an estimated total discharge of 105.6 × 106 m3 of water. The sequence of events was as follows: (1) A large debris flow entered the lake from two steep and largely non-vegetated mountain gullies located northeast of the Chileno Glacier terminus. (2) Water displaced in the lake by the debris flow increased the discharge through the Chileno Lake outflow. (3) Lake and moraine sediments were eroded by the flood. (4) Eroded sediments were redistributed downstream by the GLOF. The post-GLOF channel at the lake outlet widened in some places by >130 m and the surface elevation of the terrain lowered by a maximum of 38.8 ± 1.5 m. Farther downstream, large amounts of entrained sediment were deposited at the head of an alluvial plain and these sediments produced an ~340 m wide fan with an average increase in surface elevation over the pre-GLOF surface of 4.6 ± 1.5 m. We estimate that around 3.5 million m3 of material was eroded from the flood-affected area whilst over 0.5 million m3 of material was deposited in the downstream GLOF fan. The large debris flow that triggered the GLOF was probably a paraglacial response to glacier recession from its Little Ice Age limits. We suggest that GLOFs will continue to occur in these settings in the future as glaciers further recede in response to global warming and produce potentially unstable lakes. Detailed studies of GLOF events are currently limited in Patagonia and the information presented here will therefore help to inform future glacial hazard assessments in this region

Surface agnostic metrics for cortical volume segmentation and regression

The cerebral cortex performs higher-order brain functions and is thus implicated in a range of cognitive disorders. Current analysis of cortical variation is typically performed by fitting surface mesh models to inner and outer cortical boundaries and investigating metrics such as surface area and cortical curvature or thickness. These, however, take a long time to run, and are sensitive to motion and image and surface resolution, which can prohibit their use in clinical settings. In this paper, we instead propose a machine learning solution, training a novel architecture to predict cortical thickness and curvature metrics from T2 MRI images, while additionally returning metrics of prediction uncertainty. Our proposed model is tested on a clinical cohort (Down Syndrome) for which surface-based modelling often fails. Results suggest that deep convolutional neural networks are a viable option to predict cortical metrics across a range of brain development stages and pathologies

Pathologies of the large-N limit for RP^{N-1}, CP^{N-1}, QP^{N-1} and mixed isovector/isotensor sigma-models

We compute the phase diagram in the N\to\infty limit for lattice RP^{N-1}, CP^{N-1} and QP^{N-1} sigma-models with the quartic action, and more generally for mixed isovector/isotensor models. We show that the N=\infty limit exhibits phase transitions that are forbidden for any finite N. We clarify the origin of these pathologies by examining the exact solution of the one-dimensional model: we find that there are complex zeros of the partition function that tend to the real axis as N\to\infty. We conjecture the correct phase diagram for finite N as a function of the spatial dimension d. Along the way, we prove some new correlation inequalities for a class of N-component sigma-models, and we obtain some new results concerning the complex zeros of confluent hypergeometric functions.Comment: LaTeX, 88 pages, 33 figure

The glacial geomorphology of western Dronning Maud Land, Antarctica

Reconstructing the response of present-day ice sheets to past global climate change is important for constraining and refining the numerical models which forecast future contributions of these ice sheets to sea-level change. Mapping landforms is an essential step in reconstructing glacial histories. Here we present a new map of glacial landforms and deposits on nunataks in western Dronning Maud Land, Antarctica. Nunataks are mountains or ridges that currently protrude through the ice sheet and may provide evidence that they have been wholly or partly covered by ice, thus indicating a formerly more extensive (thicker) ice sheet. The map was produced through a combination of mapping from Worldview satellite imagery and ground validation. The sub-metre spatial resolution of the satellite imagery enabled mapping with unprecedented detail. Ten landform categories have been mapped, and the landform distributions provide evidence constraining spatial patterns of a previously thicker ice sheet

Esquistossomose mansônica no município de Pedro de Toledo (São Paulo, Brasil) onde Biomphalaria tenagophila é hospedeiro intermediário: I - Prevalência na população humana

Due to the scarce information about the epidemiological features of schistosomiasis in which the vector is Biomphalaria tenagophila, an investigation was carried in Pedro de Toledo in 1980 where such peculiarity is observed. Stool examinations (Kato-Katz method) were performed in 4,741 individuals (22.8% positive to Schistosoma mansoni eggs) of this 583 had previously received chemoterapy and 4,158 remainders, untreated. The schistosomiasis prevalence in those two groups where respectively 31.7% and 21.6%. Epidemiological investigation showed that 83.6% were autochthonous cases from the studied area: the autochthonous prevalence rate, and the intensity of infection in the untreated autochthonous cases were higher in males than in females; the intensity in the latter untreated group was low, 58.5 eggs/g feces (geometric mean). Moreover, according to the age groups the intensity of infections correlated well (r s = 0.745) with the prevalence rates. Schistosomiasis was verified to occur mostly during the leisure time and by the use of water streams for housework in rural zone. Only 0.4% out of 1,137 snails was positive for S. mansoni cercariae, apparently unchanged from the 1978 study when the human prevalence was 12.0%. The studied area presented differences and similarities in relation to the other Brazilian areas were the main intermediate host is B. glabrata.Devido à escassez de dados epidemiológicos sobre esquistossomose mansônica onde Biomphalaria tenagophila é vetor foi desenvolvido em 1980 o presente trabalho, no município paulista de Pedro de Toledo. Foram examinadas fezes de 4741 pessoas (Método de Kato-Katz) com prevalência de 22,8%; entre essas, 583 foram tratadas para a endemia anteriormente e 4158 não medicadas; as prevalências nos dois grupos for ram, respectivamente, 31,7% e 21,6%. Por investigação epidemiológica constatou-se que 83,6% dos casos foram autóctones da área estudada. Prevalência dos autóctones e intensidade de infecção nos portadores autóctones não tratados foram maiores no homem do que na mulher; a intensidade no último grupo foi baixa: 58,5 ovos/ g de fezes (média geométrica). De acordo com grupos etários, se correlacionaram bem (r s = 0,745) as intensidades de infecção e as prevalências. A infecção ocorreu, na zona rural, principalmente, durante lazer e trabalho doméstico. Somente 0,4% de 1137 moluscos foram positivos para Schistosoma mansoni. Esse índice foi, aparentemente, o mesmo em estudo de 1978 quando a prevalência humana era de 12,0%. A área estudada apresentou diferenças e semelhanças epidemiológicas em relação às áreas onde B. glabrata é o principal hospedeiro intermediário