This study was conducted to investigate the diversity and possible factors that structure the distribution and abundance of fireflies along Sungai Teratak. Six sampling occasions were conducted from March to April 2014 where ten display trees were chosen as sampling stations. Species abundance and composition of fireflies and other insects were assessed by visual assessment and sampling with aerial net. Four Pteroptyx species were discovered with difference in relative abundance, namely Pteroptyx bearni (93.1%), Pteroptyx valida (2.2%), Pteroptyx malaccae (3.9%), and Pteroptyx tener (0.8%). The results of Shannon-Weiner index, H’ was 0.316, and Simpson’s index of diversity with the value of 0.131 indicated that the firefly at Sungai Teratak was low in diversity. Abundance of firefly varied significantly between the six sampling occasions (Kruskal-Wallis = 15.382, d.f. = 5, p <0.05) but shows no difference in abundance between the ten display trees (Kruskal-Wallis = 14.181, d.f. = 9, p > 0.05). The abundance of fireflies was found to be positively correlated to the abundance of other insects (Pearson’s correlation r = 0.740, p <0.05). Comparison of fireflies’ abundance on full moon and new moon nights showed no significant difference (Mann-Whitney U = 46.00, z = -0.326, p >0.05 and Mann-Whitney U = 25.50, z = -1.945, p >0.05). Although the abundance of male (n= 232) firefly outnumbered the female (n= 149), statistical analysis proved no significant difference between both group (Mann-Whitney U = 8.50, z = -1.529, p >0.05). The mangrove trees being colonized by fireflies at Sungai Teratak was mainly from the species Avicennia alba.
Lens opacities in 98 eyes from 63 consecutive outpatients with cataract were recorded by both retroillumination and Scheimpflug slit methods by one operator. This was repeated at 26 ± 1 weeks. Image analysis used the EAS-1000 software. Cortical and posterior subcapsular (PSC) cataracts were measured in retroillumination images as density more than 14 cct units below background density. Linear densitometry of white scattered light along the optical axis was measured for slit images by both peak density and mean density (‘area under the curve’). Retroillumination images showed no discernible change over 6 months (the regression coefficient being as for the intersession reliability). Half of the Scheimpflug slit images could not be analysed because overlying cortical changes masked the more posterior parts of the lens. The other 49 eyes showed a significant increase in nuclear white scatter after 6 months, with greater degrees of change occurring in those eyes with the greatest amount of nuclear cataract initially. This is reflected by the decreased intraclass correlation coefficient (R = 0.42). The area of lens showing greatest change was the anterior fetal nucleus. The Nidek EAS-1000 is able to detect changes over a 6-month period in nuclear density but not in cortical or PSC cataract. The rate of progression of nuclear white scatter increases as the lens opacity becomes more dense. The ability to detect change in cataract over 6 months has implications for epidemiological studies and for trials of anti-cataract drugs.
Cortical and posterior subcapsular (PSC) cataracts are best quantified by a retroillumination method. We have used the Nidek EAS-1000 camera system to document such cataracts and have investigated how variability from operator input may be minimised when analysing retroillumination photographs. We then used our method to quantify the reproducibility of (i) image analysis and (ii) the system as a whole. A total of 99 eyes from 70 patients with either cortical or posterior subcapsular cataracts were photographed twice at one session. The first set of images was analysed twice and the second set once only. Cataract was classified as a density at least 14 grey scale units (cct) greater than clear lens. The brightest 2% was excluded from analysis as it corresponded to the first Purkinje image of the fixation light. The reproducibility and ‘noise’ of the analysis method were assessed by calculating the correlation coefficient (r2) and standard deviation (SD) of the differences obtained for the two analyses of the first set of images. Replicate analysis from the digitised images was excellent (r2=0.99, SD of the opacities differences ± 1.74%). For the analysis of the system as a whole, replicate photographs showed a greater variability but still good: r2=0.94 and the SD of the differences ± 4.69%. The reproducibility of the system is limited by variability of the image capture rather than by the image analysis methods.
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