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Understanding negative effects of native species on introduced taxa may suggest novel ways to control the invasive species by enhancing such effects. Previous studies have reported that the larvae of invasive cane toads (Rhinella marina) are suppressed by competition with the larvae of native anurans in Australia, but not in North America. We conducted laboratory trials to measure the effect of exposure to the larvae of Japanese frogs (Microhyla ornata, Fejervarya sakishimensis, Rhacophorus owstoni) on rates of survival, growth and development of cane toad tadpoles in Ishigaki Island, in southern Japan. Survival rates were not affected by native species, but competition with Dicroglossids and Rhacophorids (but not Microhylids) strongly reduced rates of growth and development in the tadpoles of cane toads. Dicroglossid tadpoles also reduced the body condition to toad tadpoles in addition to effects on SVL and mass. Encouraging populations of native frogs in toad-invaded areas of Japan thus may help to reduce the numbers of invasive cane toads.

Background: We have observed many people with visual impairment using tablet computers and electronic books and have previously shown that these devices can be used by people with relatively low visual acuity and contrast sensitivity. Method: An online survey was advertised to people with visual impairment using personal contacts, social media and online discussion groups. Participants were asked to specify whether they used tablet computers and/or electronic books and if so, which device they used, what they used the device for and which accessibility functions they used. Results: Forty-four of 75 (59 per cent) respondents used a tablet computer. Of these, 30 (65 per cent) used an Apple iPad. All tablet users accessed the internet on their device and more than half read electronic books, took photographs and used apps. The ability to enlarge print was seen as the most useful accessibility option, cited by 76 per cent. Forty-nine per cent used contrast adjustment and 58 per cent used speech. Only 16 of the 75 respondents (22 per cent) used an electronic reader. Enlarged print was the most popular accessibility option on ereaders. Conclusions: Tablet computers are widely used by people with visual impairment. Large print is the most commonly used accessibility option, although speech and contrast reversal are also frequently used.

Purpose We have previously shown that electronic devices can be used by people with relatively low visual acuity and contrast sensitivity. The aim of this study was to determine if people with visual impairment use smartphones to compensate their visual deficits. Methods An online survey was advertised to people with visual impairment using personal contacts, social media and online discussion groups. This survey was administered in two languages: English and Portuguese. The first author is fluent in both languages and ensured accurate translation. The questionnaire was designed to collect basic demographic information and self-reported cause of visual impairment. Participants were asked to specify whether they used smartphones, and if so which operating system they used, what they used the device for, and which accessibility functions they used. Results In total 131 responses were obtained: 75 to the English and 56 to the Portuguese survey. 93% of the respondents were younger than 64 years and 25% had no perception of light. From the total number of 131 respondents, 101 used smartphone. Of these, 57% used an Apple OS, 22% used Android and 15% used Symbian. 98% of smartphone users made phone calls with their device and sending text messages was reported by 93%. Internet navigation was used by 84%, photo capabilities were used by 53% to help them to see and by 73% for other purposes. 80% also used apps on their device. Speech navigation was used by 67% of respondents, ability to enlarge print was used by 58% and a large screen was important to 40%. Font type and contrast changes were less commonly used. Only 14% received information about these devices from a vision care professional. Other sources included online search, recommendations from friends or blind associations. Conclusions Smartphones are widely used by people with visual impairment. The current accessibility features such as speech navigation and large print allow people with visual impairment to use, PTDC/DTP-EPI/0412/2012, Prevalence and costs of visual impairment in Portugal: a hospital-based study

Purpose.: To assess the effect on visual acuity of compensating fixation instability by controlling retinal image motion in people with macular disease. Methods.: Ten patients with macular disease participated in this study. Crowded and noncrowded visual acuity were measured using an eye tracking system to compensate for fixation instability. Four conditions, corresponding to four levels of retinal image motion, were tested: no compensation (normal motion), partial compensation (reduced motion), total compensation (no motion), and overcompensation (increased motion). Fixation stability and the number of preferred retinal loci were also measured. Results.: Modulating retinal image motion had the same effect on crowded and noncrowded visual acuity (P = 0.601). When fixation instability was overcompensated, acuity worsened by 0.1 logMAR units (P < 0.001) compared with baseline (no compensation) and remained equal to baseline for all other conditions. Conclusions.: In people with macular disease, retinal image motion caused by fixation instability does not reduce either crowded or noncrowded visual acuity. Acuity declines when fixation instability is overcompensated, showing limited tolerance to increased retinal image motion. The results provide evidence that fixation instability does not improve visual acuity and may be a consequence of poor oculomotor control.

Recently, several electronic book readers have become commercially available. These consist of a low glare electronic paper screen and internal memory, which can typically hold the full text of between 150 and 2000 full-length novels. Electronic paper has a wide viewing angle of almost 1808 but a slow refresh speed of about 250 ms. Amazon’s Kindle device has 300 000 books available in electronic format, and 11 000 are available through Waterstones in the UK for the Sony Reader. Table 1 shows the parameters of these and other popular electronic books. Here, we explore the utility of these two electronic books for use by the visually impaired.

We conducted a quantitative and qualitative chemical analysis of cane toad bufadienolides-the cardioactive steroids that are believed to be the principal cane toad toxins. We found complex shifts in toxin composition through toad ontogeny: (1) eggs contain at least 28 dominant bufadienolides, 17 of which are not detected in any other ontogenetic stage; (2) tadpoles present a simpler chemical profile with two to eight dominant bufadienolides; and (3) toxin diversity decreases during tadpole life but increases again after metamorphosis (larger metamorph/juvenile toads display five major bufadienolides). Total bufadienolide concentrations are highest in eggs (2.64 +/- 0.56 mu mol/mg), decreasing during tadpole life stages (0.084 +/- 0.060 mu mol/mg) before rising again after metamorphosis (2.35 +/- 0.45 mu mol/mg). These variations in total bufadienolide levels correlate with toxicity to Australian frog species. For example, consumption of cane toad eggs killed tadpoles of two Australian frog species (Limnodynastes convexiusculus and Litoria rothii), whereas no tadpoles died after consuming late-stage cane toad tadpoles or small metamorphs. The high toxicity of toad eggs reflects components in the egg itself, not the surrounding jelly coat. Our results suggest a dramatic ontogenetic shift in the danger that toads pose to native predators, reflecting rapid changes in the types and amounts of toxins during toad development.