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Trees are useful archives of past atmospheric conditions. They have most commonly been used to infer large-scale changes in climate, industrial pollution, and the magnitude and frequency of geological hazards. While geochemical changes in tree rings have been linked to localized anthropogenic smelter pollution, their potential to track geochemical changes in volcanic degassing has not yet been fully realized. Here, we applied a new proxy using sulfur and carbon isotopes in tree rings to examine fluctuations in gas emission at Turrialba volcano, Costa Rica. Since 2009, Turrialba has emitted a persistent gas plume and increasingly frequent explosions and ash eruptions as activity has accelerated. We collected cores from a species of alder tree, Alnus acuminata, at several locations surrounding the volcano. Biannual isotopic analysis of rings demonstrated a notable δ34S shift of –5.2‰ and a similarly sharp δ13C shift of +1.3‰ in trees downwind of the plume following the onset of strong degassing in 2009. We propose that these shifts in the isotopic values of the tree correspond to those of the volcanic SO2 and CO2, and in the case of the δ13C, an additional fractionation caused by leaf impairment from exposure to volcanic SO2. This new proxy can be applied to other volcanoes as a novel method of obtaining a temporal record of degassing, a crucial tool for volcano monitoring. Los árboles son archivos útiles de las condiciones atmosféricas pasadas. Se han utilizado con mayor frecuencia para inferir cambios a gran escala en el clima, la contaminación industrial y la magnitud y frecuencia de los peligros geológicos. Si bien los cambios geoquímicos en los anillos de los árboles se han relacionado con la contaminación antropogénica localizada de las fundiciones, su potencial para rastrear los cambios geoquímicos en la desgasificación volcánica aún no se ha realizado completamente. Aquí, aplicamos un nuevo proxy usando isótopos de azufre y carbono en anillos de árboles para examinar las fluctuaciones en la emisión de gas en el volcán Turrialba, Costa Rica. Desde 2009, Turrialba ha emitido una columna de gas persistente y explosiones y erupciones de cenizas cada vez más frecuentes a medida que la actividad se ha acelerado. Recolectamos núcleos de una especie de aliso, Alnus acuminata, en varios lugares alrededor del volcán. El análisis isotópico semestral de los anillos demostró un cambio notable de δ34S de –5,2 ‰ y un cambio de δ13C igualmente pronunciado de + 1,3 ‰ en los árboles a sotavento del penacho tras el inicio de una fuerte desgasificación en 2009. Proponemos que estos cambios en los valores isotópicos del árbol corresponden a los del SO2 volcánico y CO2, y en el caso del δ13C, un fraccionamiento adicional causado por el deterioro foliar por exposición al SO2 volcánico. Este nuevo proxy se puede aplicar a otros volcanes como un método novedoso para obtener un registro temporal de desgasificación, una herramienta crucial para el monitoreo de volcanes. McGill University, Montréal, Québec Université du Québec à Montréal, Montréal Universidad Nacional, Costa Rica Carleton University, Ottawa, Ontario Department of Earth & Planetary Sciences, McGill University, Montréal, Québec Geotop Research Centre on the Dynamics of the Earth System, Université du Québec à Montréal, Montréal Département de Géographie, Université du Québec à Montréal, Montréal Observatorio Vulcanológico y Sismológico de Costa Rica Département des Sciences de la Terre et de l’Atmosphère, Université du Québec à Montréal, Montréal Department of Engineering, Carleton University, Ottawa

Los gases volcánicos son importantes herramientas de pronóstico de erupciones que se utilizan a menudo en el monitoreo de volcanes. Sin embargo, la recolección de muestras de gas requiere que los científicos ingresen a áreas volcánicas de alto riesgo. Los drones son las herramientas perfectas para que los vulcanólogos accedan a estas zonas de peligro. Aunque se están volviendo rápidamente populares entre la comunidad científica para la fotografía y el mapeo aéreo, pocos estudios han intentado medir cuantitativamente las emisiones de gases con drones [por ejemplo, McGonigle et al., 2008; Mori et al., 2016]. Un dron, o vehículo aéreo no tripulado (UAV), es un dispositivo de control remoto que permite al piloto permanecer a una distancia segura de un cráter activo mientras el dron se maniobra hacia el sitio de interés . Los drones se pueden pilotar manualmente o con un sistema de navegación autónomo. Se pueden montar sensores de gas compactos en el dron que toman medidas mientras el dron está en el aire. Volcanic gases are important eruption forecasting tools often used in volcano monitoring. However, collecting gas samples requires scientists to enter high-risk volcanic areas. Drones are the perfect tools for volcanologists to access these danger zones. Although they’re rapidly becoming popular among the scientific community for photography and aerial mapping, few studies have attempted to quantitatively measure gas emissions with drones [e.g., McGonigle et al., 2008; Mori et al., 2016]. A drone, or unmanned aerial vehicle (UAV), is a remote-controlled device that allows a pilot to remain a safe distance from an active crater while the drone is maneuvered to the site of interest. Drones can be piloted manually or with an autonomous navigation system. Compact gas sensors can be mounted onto the drone that take measurements while the drone is in the air. McGill University Johannes Gutenberg University Mainz, Mainz, Germany Universidad de Costa Rica Universidad Nacional, Costa Rica Observatorio Vulcanológico y Sismológico de Costa Rica Department of Earth and Planetary Sciences, McGill University Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg University Mainz, Mainz, Germany GasLab, CICANUM, Physics School, Universidad de Costa Rica

Purpose To evaluate the safety and efficacy of photorefractive keratectomy (PRK) 16 years postoperatively. Setting Refractive Laser Suite, Mater Private Hospital, Dublin, Ireland. Design Cohort study. Methods Myopic PRK was performed using the UV200 excimer laser with a 5.0 mm ablation zone. The following were evaluated in patients returning 16 years postoperatively: refractive stability, refractive predictability, corrected visual acuity, corneal haze, and subjective patient symptoms (eg, glare, halos). Results Most of the 120 eyes (80 patients) were followed for 2 years or more; 23 patients (39 eyes) were followed for 16 years. Preoperatively, the spherical equivalent (SE) ranged from −1.75 to −7.25 diopters (D) and astigmatism from 0.00 to 1.50 D. At 2 years, the mean SE was −0.25 D and at 16 years, −0.58 D. Overall, 31 eyes (79.5%) were within ±1.00 D of emmetropia, with 6 eyes (15.4%) between 1.00 D and 2.00 D and 2 eyes (5.1%) between 2.00 D and 3.00 D. The final uncorrected distance visual acuity was 20/20 or better in 27 eyes (69.2%) and 20/30 or better in 36 eyes (92.3%). Eight eyes (20.5%) lost 1 line of corrected distance visual acuity. Four eyes (10.3%) had visible haze and 7 eyes (17.9%) had hemosiderin. All patients stated they would have the procedure again. Conclusion Photorefractive keratectomy was safe and effective in the treatment of myopia up to −7.00 D, and all patients reported being satisfied. There appeared to be slight regression over the follow-up period. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Purpose: To compare outcomes of customized/wavefront guided with conventional ablation in myopic patients with or without astigmatism undergoing laser in situ keratomileusis. Methods: A prospective, comparative, contralateral eye study was performed. Sixty-eight eyes of 34 myopic patients with similar refractive error in both eyes were included. One eye was randomly selected to undergo conventional and the fellow eye customized ablation. Surgery was performed using the Technolas 217z laser (Bausch & Lomb, Surrey, UK). Uncorrected visual acuity, manifest refractive spherical equivalent (MRSE), astigmatism, aberrometry and contrast sensitivity were recorded pre and 3 months postoperatively. Results: Mean MRSE treated in the conventional and customized groups were 3.77 ± 1.61 dioptres and −3.83 ± 1.59 dioptres respectively. Three months postoperatively there was no significant difference between the groups in mean MRSE (p = 0.99) or cylinder (p = 0.56). The factor increase in postoperative total higher order aberrations (HOAs) was less in the customized (1.32) compared with the conventional (1.54) treatment group but did not reach statistical significance (p = 0.08). Scotopic contrast sensitivity decreased significantly postoperatively in the conventional but not in the customized treatment group. Conclusion: Visual acuity and refractive error outcomes were similar in both treatment group and no patient preference was observed. Customized ablation was associated with a smaller but not statistically significant postoperative increase in HOAs, better preservation of scotopic contrast sensitivity, quicker treatment time and removal of less corneal tissue.

The study evaluates the effectiveness of a sibling support programme (Sibshops) involving three disability agencies in Cork, Ireland. Qualitative and quantitative data were obtained using semi-structured interviews and the Piers-Harris Children’s Self-Concept Scale with siblings, together with parent feedback. Results from the Piers-Harris showed that there was no significant increase in sibling self-esteem following attendance at the Sibshops. However, the interviews revealed that the majority of siblings enjoyed and benefited from the Sibshops. Parents reported satisfaction with the Sibshops and felt that their children had benefited. Reflections on the experience of working on an interagency basis are outlined. Recommendations are made regarding further research and development in the organization of Sibshops and in staffing and staff training.

Purpose To evaluate the effects of laser in situ keratomileusis (LASIK) and laser-assisted subepithelial keratectomy (LASEK) on dry-eye disease markers including tear osmolarity, Schirmer testing, and the ocular surface disease index (OSDI). Setting Laser Suite, Mater Private Hospital, Dublin, Ireland. Design Prospective controlled cross-sectional observation study. Methods In a single center, consecutive eyes that had LASIK or LASEK had dry-eye disease markers assessed preoperatively and 3, 6, and 12 months postoperatively. Results In LASIK eyes (n = 50), the mean tear osmolarity was significantly elevated (by 2.8%) at 12 months (P=.009, Student t test). The mean Schirmer test values were not significantly altered postoperatively in either group. The mean OSDI was maximum in LASIK eyes at 3 months (mean follow-up 7.2 months ± 8.2 [SD]) and in LASEK eyes (n = 35) preoperatively (mean follow-up 9.1 ± 9.7 months). Conclusions There were no significant differences in dry-eye disease markers or tear osmolarity between LASIK and LASEK patients at any stage after surgery up to 1 year. Although tear osmolarity remains one of the highest predictive tests of dry eye, it is complementary with other diagnostic criteria in the context of dry eye after refractive surgery. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

AIM To identify the risk factors for, and to report the microbiological findings and clinical outcomes of, severe microbial keratitis (MK). METHODS This was a retrospective study of all cases of presumed MK admitted to a tertiary referral center over a 2-year period (September 2001 to August 2003). Data recorded included demographic data, details relating to possible risk factors, results of microbiological studies, clinical findings at presentation, and clinical and visual outcomes. RESULTS Ninety patients were admitted with a diagnosis of presumed MK during the study period. The mean age of patients was 45 +/- 32 years, and the male to female ratio was 47:43 (52.2%:47.7%). Predisposing risk factors for MK included contact lens wear (37; 41.1%), anterior segment disease (19; 21.1%), ocular trauma (13; 14.4%), systemic disease (5; 5.6%), and previous ocular surgery (1; 1.1%). Cultured organisms included gram-negative bacteria (17; 51.5%), gram-positive bacteria (11, 33.3%), acanthamoeba (2; 6.1%), and fungi (1; 3%). Visual acuity improved significantly after treatment [mean best-corrected visual acuity (+/-standard deviation) at presentation: 0.76 (+/-0.11); mean best-corrected visual acuity at last follow-up: 0.24 (+/-0.07); P < 0.001]. Secondary surgical procedures were required in 18 (20%) cases, and these included punctal cautery (1; 1.1%), tissue glue repair of corneal perforation (2; 2.2%), tarsorrhaphy (9; 9.9%), Botulinum toxin-induced ptosis (1; 1.1%), penetrating keratoplasty (3; 3.3%), and evisceration (2; 2.2%). CONCLUSIONS Contact lens wear remains a significant risk factor for severe MK. MK remains a threat to vision and to the eye, but the majority of cases respond to prompt and appropriate antimicrobial therapy.

We performed a prospective study of the safety, efficacy, and effect of the newer version on HOAs, which has not been described. LogMAR corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA), manifest refractive spherical equivalent (MRSE), endothelial cell density (ECD), and HOAs were recorded preoperatively and 6, 12, and 24 months after implantation of the pIOL. Implantation was performed by a single surgeon (M.O.K.) in 66 myopic eyes of 37 patients (mean MRSE 8.9 diopters [D] G 1.9 [SD]). At 24 months, the mean MRSE was 0.3 D; 69.4% of eyes had a UDVA of less than or equal to 0.0 logMAR and 100% had a UDVA of less than or equal to 0.18 logMAR. Laser-assisted subepithelial keratomileusiswasperformedin6%ofeyestocorrectaresidual refractive error. Thirty-two eyes (48.5%) gained 1 or more lines of CDVA, and no eye lost a line of CDVA. A statistically significant 17% decrease in the root mean square (RMS) of vertical trefoil Z(3,1) was noted (P Z .016, Student t test, Table 1), and there was a statistically significant 48% decrease in 4th-order spherical aberration, Z(4,0), (P Z .007