Population size, habitat and conservation status of an Endangered species, Macrozamia johnsonii (Zamiaceae)

Macrozamia johnsonii D. Jones & K. Hill is a locally endemic cycad (family Zamiaceae) with a restricted occurrence in north-eastern New South Wales and currently listed as Endangered. Based on recent field surveys, its mean population size is estimated as approximately 3.5 million mature plants, with the lower bound of the 95% confidence interval at 1.9 million mature plants. Thirty percent of the population occurs in a formal reserve. Macrozamia johnsonii occurs in grassy eucalypt forest, shrubby wet sclerophyll forest and in rainforest. It occurs most frequently on steeply sloping sites with high moisture index. There are no immediate significant threats to the species although timber harvesting is judged to be a potential longer term threat to part of the population. The conservation status of Macrozamia johnsonii is assessed using IUCN criteria and thresholds, using population size and extent data from this study and a plausible range of values based on available circumstantial evidence for parameters for which quantitative estimates are not available. Based on this assessment, we regard the conservation status of Macrozamia johnsonii to be in the category of Least Concern, and that its current listing as an Endangered species under the NSW Threatened Species Conservation Act (1995) needs to be revised

'You've got dry macular degeneration, end of story': a qualitative study into the experience of living with non-neovascular age-related macular degeneration.

BACKGROUND/OBJECTIVES: To investigate the impact of non-neovascular (dry) age-related macular degeneration (AMD) on the person with respect to diagnosis, vision loss and coping strategies. SUBJECTS/METHODS: Volunteers with dry AMD with a range of disease severity were given an eye examination and asked to describe aspects of their experience with dry AMD in a semi-structured interview. Interviews were audio-recorded, transcribed, and subjected to Framework analysis. Overarching themes were pre-defined, whilst subthemes were derived from the data. RESULTS: Twenty-seven participants (81% female), with early (n = 3), intermediate (n = 16) and advanced dry AMD (GA; n = 8) were interviewed. Median (interquartile range) age (years), logMAR binocular visual acuity and Pelli-Robson contrast sensitivity were 76 (71, 80), 0.2 (0.18, 0.40) and 1.65 (1.35, 1.93), respectively. Overarching themes (and subthemes) were: diagnosis (relationship with healthcare professional, psychological impact of diagnosis, and knowledge of AMD, both pre- and post-diagnosis), impact of visual loss (functional and psychological) and coping strategies (help from others and personal strategies). Many participants reported feelings of distress at the time of diagnosis and, particularly noteworthy, several reported a constant fear of their condition worsening. CONCLUSIONS: Dry AMD, for which there is currently no treatment, can have a significant impact on individuals, even in its early stages, before significant functional vision loss is manifest, as well as in its intermediate and advanced stages. Results from this study offer important insight into the experience of living with dry AMD not previously explored. Moreover, the results have the potential to serve as an educational resource for eyecare professionals

Determining Optimal Test Parameters for Assessing Dark Adaptation in People With Intermediate Age-Related Macular Degeneration

Purpose: The primary aim was to determine optimal test conditions for evaluating dark adaptation in intermediate age-related macular degeneration (iAMD) in order to minimize test time while maintaining diagnostic sensitivity. Methods: People with AMD and age-similar controls were recruited (aged >55 years). Rod intercept time (RIT) was assessed after a 76%, 70%, and 65% rhodopsin bleach at 5° eccentricity and 76% and 70% bleach at 12°. Test order was randomized and a 30-minute washout period added between tests. Results were compared between control and iAMD groups and receiver operating characteristics (ROC) curves were constructed. Results: A total of 26 participants with variable grades of macular health attended for two visits. There was a statistically significant difference in average RIT between the control and iAMD groups at 5° (median, IQR controls = 5.8 minutes, 3.8–7.5; iAMD = 20.6 minutes, 11.1–30.0; Mann-Whitney, P = 0.01) and at 12° (mean, controls: 4.54 minutes ± 2.12 SD, iAMD = 7.72 minutes ± 3.37 SD; independent samples t-test, P = 0.03) following a 76% bleach. Area under the ROC curves was 0.83 (confidence interval [CI]: 0.64–1.0) and 0.79 (CI: 0.59–0.99) for these two test conditions, respectively. Five participants (45%) in the iAMD group had RITs >20 minutes for 76% bleach at 5°, but none for any other test condition. Conclusions: Nearly half of the participants with iAMD produced unacceptably long recovery times (>20 minutes) using a 76% bleach at 5° eccentricity. The 76% bleach at 12° provided almost equivalent separation between AMD and controls but recovery was achieved within 20 minutes

Measuring dynamic levels of self-perceived anxiety and concern during simulated mobility tasks in people with non-neovascular age-related macular degeneration.

BACKGROUND/AIMS: To assess response to real-world mobility scenarios in people with dry age-related macular degeneration (AMD) using a computer-based test. METHODS: Participants were shown 18 point-of-view computer-based movies simulating walking through real-world scenarios, and pressed a button during scenes which would cause them self-perceived anxiety or concern in their day-to-day life. Button pressure was recorded throughout. Pressure traces were generated, which aligned with each movie time point. Group averages based on AMD severity were generated. Bootstrapped confidence intervals (CIs) for responses by group were generated around traces. Traces were examined to discover events causing the greatest differences between groups. RESULTS: Participants had early/no AMD (n=8), intermediate AMD (n=7) or geographic atrophy (n=15 (GA)). Median (IQR) logMAR visual acuity was 0.04 (-0.04, 0.18), 0.26 (0.10, 0.40) and 0.32 (0.20, 0.56), respectively. Participants with intermediate AMD or GA recorded greater pressure than those with early and no AMD (Kruskal-Wallis, p=0.04). Four events involving navigating stairs and three under low luminance elicited greatest differences between groups (p<0.001). CONCLUSION: People with intermediate AMD or GA likely experience higher levels of concern associated with mobility. The test highlights areas of specific concern. Results should be useful in patient management and educating the public about the everyday effects of AMD

The effect of non-neovascular age-related macular degeneration on face recognition performance

PURPOSE: There is a well-established research base surrounding face recognition in patients with age-related macular degeneration (AMD). However, much of this existing research does not differentiate between results obtained for 'wet' AMD and 'dry' AMD. Here, we test the hypothesis that face recognition performance is worse in patients with dry AMD compared with visually healthy peers. METHODS: Patients (>60 years of age, logMAR binocular visual acuity 0.7 or better) with dry AMD of varying severity and visually healthy age-related peers (controls) completed a modified version of the Cambridge Face Memory Test (CFMT). Percentage of correctly identified faces was used as an outcome measure for performance for each participant. A 90% normative reference limit was generated from the distribution of CFMT scores recorded in the visually healthy controls. Scores for AMD participants were then specifically compared to this limit, and comparisons between average scores in the AMD severity groups were investigated. RESULTS: Thirty patients (median [interquartile range] age of 76 [70, 79] years) and 34 controls (median age of 70 [64, 75] years) were examined. Four, seventeen and nine patients were classified as having early, intermediate and late AMD (geographic atrophy) respectively. Five (17%) patients recorded a face recognition performance worse than the 90% limit (Fisher's exact test, p = 0.46) set by controls; four of these had geographic atrophy. Patients with geographic atrophy identified fewer faces on average (±SD) (61% ± 22%) than those with early and intermediate AMD (75 ± 11%) and controls (74% ± 11%). CONCLUSIONS: People with dry AMD may not suffer from problems with face recognition until the disease is in its later stages; those with late AMD (geographic atrophy) are likely to have difficulty recognising faces. The results from this study should influence the management and expectations of patients with dry AMD in both community practice and hospital clinics

Interactions of heavy nuclei, Kr, Xe and Ho, in light targets

Over the past few years, the HEAO-3 measurements of the abundances of ultra-heavy cosmic ray nuclei (Z 26) at earth have been analyzed. In order to interpret these abundances in terms of a source composition, allowance must be made for the propagation of the nuclei in the interstellar medium. Vital to any calculation of the propagation is a knowlege of the total and partial interaction cross sections for these heavy nuclei on hydrogen. Until recently, data on such reactions have been scarce. However, now that relativistic heavy ion beams are available at the LBL Bevalac, some of the cross sections of interest can be measured at energies close to those of the cosmic ray nuclei being observed. During a recent calibration at the Bevalac of an array similar to the HEAO-C3 UH-nuclei detector, targets of raphite (C), polyethylene (CH2), and aluminum were exposed to five heavy ion beams ranging in charge (Z) from 36 to 92. Total and partial charge changing cross sections for the various beam nuclei on hydrogen can be determined from the measured cross sections on C and CH2, and will be applied to the propagation problem. The cross sections on Al can be used to correct the abundances of UH cosmic rays observed in the HEAO C-3 detector for interactions in the detector itself

Switching Casimir forces with Phase Change Materials

We demonstrate here a controllable variation in the Casimir force. Changes in the force of up to 20% at separations of ~100 nm between Au and AgInSbTe (AIST) surfaces were achieved upon crystallization of an amorphous sample of AIST. This material is well known for its structural transformation, which produces a significant change in the optical properties and is exploited in optical data storage systems. The finding paves the way to the control of forces in nanosystems, such as micro- or nanoswitches by stimulating the phase change transition via localized heat sources.Comment: 7 pages, 3 figures The AFM images for the inset in Fig.2 were replaced with new ones as obtained with tips having high aspect rati

Imaging of tumor hypoxia with [124I]IAZA in comparison with [18F]FMISO and [18F]FAZA – first small animal PET results

PURPOSE: This study was performed to compare the 2-nitroimidazole derivatives [124I]IAZA, [18F]FAZA and well known [18F]FMISO in visualization of tumor hypoxia in a mouse model of human cancer using small animal PET. METHODS: PET imaging of female Balb/c nude mice bearing A431 tumors on a Phillips Mosaic small animal PET scanner was performed 3 h p.i. for all three tracers. Mice injected with [124I]IAZA were scanned again after 24 h and 48 h. In addition to the mice breathing air, in the case of [18F]FAZA and [124I]IAZA a second group of mice for each tracer was kept in an atmosphere of carbogen gas (5% of CO2 + 95 % of O2; from 1 h before to 3 h after injection) to evaluate the oxygenation dependency on uptake (all experiments n = 4). After the final PET scan animals were sacrificed and biodistribution was studied. RESULTS: Mice injected with [18F]FAZA displayed significantly higher tumor-to background (T/B) ratios (5.19 +/- 0.73) compared to those injected with [18F]FMISO (3.98 +/- 0.66; P $lt; 0.05) or [124I]IAZA (2.06 +/- 0.26; P$lt; 0.001) 3 h p.i. Carbogen breathing mice showed lower ratios ([18F]FAZA: 4.06 +/- 0.59; [124I]IAZA: 2.02 +/- 0.36). The T/B ratios increased for [124I]IAZA with time (24 h: 3.83 +/- 0.61; 48 h: 4.20 +/- 0.80), but after these late time points the absolute whole body activity was very low, as could be seen from the biodistribution data (< 0.1 %ID/g for each investigated organ) and ratios were still lower than for [18F]FAZA 3 h p.i. Due to de-iodination uptake in thyroid was high. Biodistribution data were in good agreement with the PET results. CONCLUSIONS: [18F]FAZA showed superior biokinetics compared to [18F]FMISO and [124I]IAZA in this study. Imaging at later time points that are not possible with the short lived 18F labeled tracers resulted in no advantage for [124I]IAZA, i. e. tumor to normal tissue ratios could not be improved. © 1999 Canadian Society for Pharmaceutical Sciences