Long-term monitoring of the short period SU UMa-type dwarf nova, V844 Herculis

We report on time-resolved CCD photometry of four outbursts of a short-period SU UMa-type dwarf nova, V844 Herculis. We successfully determined the mean superhump periods to be 0.05584(64) days, and 0.055883(3) for the 2002 May superoutburst, and the 2006 April-May superoutburst, respectively. During the 2002 October observations, we confirmed that the outburst is a normal outburst, which is the first recorded normal outburst in V844 Her. We also examined superhump period changes during 2002 May and 2006 April-May superoutbursts, both of which showed increasing superhump period over the course of the plateau stage. In order to examine the long-term behavior of V844 Her, we analyzed archival data over the past ten years since the discovery of this binary. Although photometry is not satisfactory in some superoutbursts, we found that V844 Her showed no precursors and rebrightenings. Based on the long-term light curve, we further confirmed V844 Her has shown almost no normal outbursts despite the fact that the supercycle of the system is estimated to be about 300 days. In order to explain the long-term light curves of V844 Her, evaporation in the accretion disk may play a role in the avoidance of several normal outbursts, which does not contradict with the relatively large X-ray luminosity of V844 Her.Comment: 10 pages, 11 figures, accepted for PAS

Clinical characteristics and visual outcomes of work-related open globe injuries in Japanese patients

Purpose: To investigate the clinical characteristics and visual outcomes of patients with work-related open globe injuries (OGIs) and compare them with patients with non-work-related OGIs. Design: Retrospective, observational, multicentre, case-control study. Methods: A total of 374 patients with work-related OGIs and 170 patients with non-work-related OGIs who presented to hospitals that belong to the Japan-Clinical Research of Study group from 2005 to 2015 were included in this study. Clinical data including age, sex, initial and final visual acuity, type of open globe injury, lens status, zone of injury, wound length, and presence of proliferative vitreoretinopathy, retinal detachment, expulsive haemorrhage, and endophthalmitis were recorded. Main Outcome Measures: Visual acuity. Results Work-related OGIs were associated with younger age, male sex, better initial and final visual acuity, more laceration, smaller wounds, presence of retinal detachment, and expulsive haemorrhage, compared with non-work-related OGIs. Multiple regression analysis revealed that final visual acuity is significantly associated with initial visual acuity, wound length, and the presence of proliferative vitreoretinopathy in work-related OGIs. Conclusions: Work-related OGIs showed better visual outcomes than other OGIs. Initial visual acuity, wound length, and the presence of proliferative vitreoretinopathy are predictors of visual outcomes in patients with work-related OGIs