The paradox in ageing well: stories of older women in the Australian women's weeky

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Conspicuous males suffer higher predation risk: visual modelling and experimental evidence from lizards

Colour pattern variation is a striking and widespread phenomenon. Differential predation risk between individuals is often invoked to explain colour variation, but empirical support for this hypothesis is equivocal. We investigated differential conspicuousness and predation risk in two species of Australian rock dragons, Ctenophorus decresii and C. vadnappa. To humans, the coloration of males of these species varies between 'bright' and 'dull'. Visual modelling based on objective colour measurements and the spectral sensitivities of avian visual pigments showed that dragon colour variants are differentially conspicuous to the visual system of avian predators when viewed against the natural background. We conducted field experiments to test for differential predation risk, using plaster models of 'bright' and 'dull' males. 'Bright' models were attacked significantly more often than 'dull' models suggesting that differential conspicuousness translates to differential predation risk in the wild. We also examined the influence of natural geographical range on predation risk. Results from 22 localities suggest that predation rates vary according to whether predators are familiar with the prey species. This study is among the first to demonstrate both differential conspicuousness and differential predation risk in the wild using an experimental protocol. (C) 2003 Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour.

Relationship between cranio-cervical flexion range of motion and pressure change during the cranio-cervical flexion test

The purpose of this study was to quantify the sagittal angular displacement of the head (cranio-cervical flexion) for the five incremental stages of the cranio-cervical flexion test (CCFT). Range of cranio-cervical flexion during the CCFT was measured using a digital imaging method in 20 healthy volunteer subjects. The intra- and inter-rater reliability of the digital imaging technique for the assessment of this movement were also examined. The results of this study demonstrated a linear relationship between the incremental pressure targets of the CCFT and the percentages of full range cranio-cervical flexion range of motion (ROM) measured in the supine lying position of the test using a digital imaging technique. A mean of 22.9% full range cranio-cervical flexion was used to reach the first pressure target of the CCFT followed by linear increments up to 76.6% for the last stage of the test. An increasing amount of cranio-cervical flexion ROM was used to achieve the five successive stages of the CCFT reflecting an increasing contractile demand on the deep cervical flexor muscles. Excellent inter-rater (ICC = 0.994) and intra-rater reliability (ICC = 0.988-0.998) were demonstrated for the angular measurements using this digital imaging technique. (C) 2003 Elsevier Science Ltd. All rights reserved.

Changes in postural stability in women aged 20 to 80 years

Background. A study of postural stability was undertaken to identify the relationship between vision and support surface across age decades. Understanding when reliance on vision for postural stability emerges and the support conditions contributing to this instability may provide the evidence required to introduce falls-prevention strategies in younger age decades. Methods. We measured postural stability in 453 women aged 20 to 80 years using the Balance Master force-plate system while the women performed the modified Clinical Test for the Sensory Interaction and Balance (firm and foam surfaces, eyes open and closed) and the Single-Limb Stance Test (eyes open and closed). Results. Women in their 60s and 70s were more unstable than younger women in bilateral stance on a firm surface with the eyes closed. This instability was evident from the 50s when a foam surface was introduced and from the 40s when single-limb stance was tested with eyes closed. A further decline in stability was demonstrated for each subsequent decade when the eyes were closed in single-limb stance. Conclusions. Age, visual condition, and support surface were significant variables influencing postural stability in women. Reliance on vision for postural stability was evident for women from the 40s when single-limb stance was tested, from the 50s when bilateral stance on foam was tested, and from the 60s when a firm surface was used. The cause(s) of this decline in stability requires further investigation, and screening for postural instability between the ages of 40 and 60 is advocated.

Assessing childrens competence in computer interactions: Preliminary reliability and validity of the test of mouse proficiency

The Test of Mouse Proficiency (TOMP) was developed to assist occupational therapists and education professionals assess computer mouse competency skills in children from preschool to upper primary (elementary) school age. The preliminary reliability and validity of TOMP are reported in this paper. Methods used to examine the internal consistency, test-retest reliability, and criterion- and construct-related validity of the test are elaborated. In the continuing process of test refinement, these preliminary studies support to varying degrees the reliability and validity of TOMP. Recommendations for further validation of the assessment are discussed along with indications for potential clinical application.

Rapid colour changes in multilayer reflecting stripes in the paradise whiptail, Pentapodus paradiseus

The Paradise whiptail (Pentapodus paradiseus) has distinct reflective stripes on its head and body. The reflective stripes contain a dense layer of physiologically active iridophores, which act as multilayer reflectors. The wavelengths reflected by these stripes can change from blue to red in 0.25 s. Transmission electron microscopy revealed that the iridophore cells contain plates that are, on average, 51.4 nm thick. This thickness produces a stack, which acts as an ideal quarter-wavelength multilayer reflector (equal optical thickness of plates and spaces) in the blue, but not the red, region of the spectrum. When skin preparations were placed into hyposmotic physiological saline, the peak wavelength of the reflected light shifted towards the longer (red) end of the visible spectrum. Hyperosmotic saline reversed this effect and shifted the peak wavelength towards shorter (blue/UV) wavelengths. Norepinephrine (100 mumol l(-1)) shifted the peak wavelength towards the longer end of the spectrum, while adenosine (100 mumol l(-1)) reversed the effects of norepinephrine. The results from this study show that the wavelength changes are elicited by a change of similar to70 nm in the distance between adjacent plates in the iridophore cells.

Influence of ageing, heat shock treatment and in vivo total antioxidant status on gene-expression profile and protein synthesis in human peripheral lymphocytes

Ageing results in a progressive, intrinsic and generalised imbalance of the control of regulatory systems. A key manifestation of this complex biological process includes the attenuation of the universal stress response. Here we provide the first global assessment of the ageing process as it affects the heat shock response, utilising human peripheral lymphocytes and cDNA microarray analysis. The genomic approach employed in our preliminary study was supplemented with a proteomic approach. In addition, the current study correlates the in vivo total antioxidant status with the age-related differential gene expression as well as the translational kinetics of heat shock proteins (hsps). Most of the genes encoding stress response proteins on the 4224 element microarray used in this study were significantly elevated after heat shock treatment of lymphocytes obtained from both young and old individuals albeit to a greater extent in the young. Cell signaling and signal transduction genes as well as some oxidoreductases showed varied response. Results from translational kinetics of induction of major hsps, from 0 to 24 It recovery period were broadly consistent with the differential expression of HSC 70 and HSP 40 genes. Total antioxidant levels in plasma from old individuals were found to be significantly lower by comparison with young, in agreement with the widely acknowledged role of oxidant homeostasis in the ageing process. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.

Ultraviolet signals in birds are special

Recent behavioural experiments have shown that birds use ultraviolet (UV)-reflective and fluorescent plumage as cues in mate choice. It remains controversial, however, whether such UV signals play a special role in sexual communication, or whether they are part of general plumage coloration. We use a comparative approach to test for a general association between sexual signalling and either UV-reflective or fluorescent plumage. Among the species surveyed, 72% have UV colours and there is a significant positive association between UV reflectance and courtship displays. Among parrots (Psittaciformes), 68% of surveyed species have fluorescent plumage, and again there is a strong positive association between courtship displays and fluorescence. These associations are not artefacts of the plumage used in courtship displays, being generally more 'colourful' because there is no association between display and colours lacking UV reflectance or fluorescence. Equally, these associations are not phylogenetic artefacts because all results remain unchanged when families or genera, rather than species, are used as independent data points. We also find that, in parrots, fluorescent plumage is usually found adjacent to UV-reflective plumage. Using a simple visual model to examine one parrot, the budgerigar Melopsittacus undulatus, we show that the juxtaposition of UV-reflective and fluorescent plumage leads to a 25-fold increase in chromatic contrast to the budgerigar's visual system. Taken together, these results suggest that signals based on UV contrast are of special importance in the context of active sexual displays. We review briefly six hypotheses on why this may be the case: suitability for short-range signalling; high contrast with backgrounds; invisibility to predators; exploitation of pre-existing sensory biases; advertisement of feather structure; and amplification of behavioural signals.

Climate of fear in organisational settings: Construct definition, measurement and a test of theory

This paper reports a study that explored a new construct: climate of fear. We hypothesised that climate of fear would vary across work sites within organisations, but not across organisations. This is in contrast a to measures of organisational culture, which were expected to vary both within and across organisations. To test our hypotheses, we developed a new 13-item measure of perceived fear in organisations and tested it in 20 sites across two organisations (N = 209). Culture variables measured were innovative leadership culture, and communication culture. Results were that climate of fear did vary across sites in both organisations, while differences across organisations were not significant, as we anticipated. Organisational culture, however, varied between the organisations, and within one of the organisations. The climate of fear scale exhibited acceptable psychometric properties.

New fluorescence parameters for monitoring photosynthesis in plants - 1. The effect of illumination on the fluorescence parameters of the JIP-test

Chlorophyll fluorescence measurements have a wide range of applications from basic understanding of photosynthesis functioning to plant environmental stress responses and direct assessments of plant health. The measured signal is the fluorescence intensity (expressed in relative units) and the most meaningful data are derived from the time dependent increase in fluorescence intensity achieved upon application of continuous bright light to a previously dark adapted sample. The fluorescence response changes over time and is termed the Kautsky curve or chlorophyll fluorescence transient. Recently, Strasser and Strasser (1995) formulated a group of fluorescence parameters, called the JIP-test, that quantify the stepwise flow of energy through Photosystem II, using input data from the fluorescence transient. The purpose of this study was to establish relationships between the biochemical reactions occurring in PS II and specific JIP-test parameters. This was approached using isolated systems that facilitated the addition of modifying agents, a PS II electron transport inhibitor, an electron acceptor and an uncoupler, whose effects on PS II activity are well documented in the literature. The alteration to PS II activity caused by each of these compounds could then be monitored through the JIP-test parameters and compared and contrasted with the literature. The known alteration in PS II activity of Chenopodium album atrazine resistant and sensitive biotypes was also used to gauge the effectiveness and sensitivity of the JIP-test. The information gained from the in vitro study was successfully applied to an in situ study. This is the first in a series of four papers. It shows that the trapping parameters of the JIP-test were most affected by illumination and that the reduction in trapping had a run-on effect to inhibit electron transport. When irradiance exposure proceeded to photoinhibition, the electron transport probability parameter was greatly reduced and dissipation significantly increased. These results illustrate the advantage of monitoring a number of fluorescence parameters over the use of just one, which is often the case when the F-V/F-M ratio is used.

Effect of storage time and conditions on the seed coat colour of Australian adzuki beans

Two varieties of adzuki beans (Vigna angularis), Bloodwood and Erimo, were stored at temperatures of 10, 20 or 30degreesC, and relative humidities (RH) 40 or 65%, and samples were analysed at 0, 1.5, 3 and 6 months. Storage at 30degreesC for > 1.5 months caused a significant decrease in the a(star) and b(star) colour values and darkening of the seed coat. Beans stored at 65% RH had lower L-star but higher a(star) and b(star) colour values than those stored at 40% RH. Bloodwood and Erimo samples showed similar trends in colour during storage. The best storage conditions for the preservation of the adzuki colour were 10degreesC and 65% RH. The Australian beans had lower L-star, a(star) and b(star) colour values than Japanese Erimo-shouzu beans and storage increased the difference.

Transient evoked otoacoustic emissions in adults: a comparison between two test protocols

This study compares the performance of the Quickscreen and Default protocols of the ILO-96 Otodynamics Analyzer in recording transient evoked otoacoustic emissions (TEOAEs) from adults using clinical decision analysis. Data were collected from 25 males (mean age = 29.0 years, SD = 6.8) and 35 females (mean age = 28.1 years, SD = 9.6). The results showed that the mean signal-to-noise ratios obtained from the Quickscreen were significantly greater than those from the Default protocol at 1,2, and 4 kHz. The comparison of the performance of the two protocols, based on the results using receiver operating characteristics curves, revealed a higher performance of the Quickscreen than the Default protocol at 1 and 4 kHz but not at 2 kHz. In view of the enhanced performance of the Quickscreen over the Default protocol in general, the routine use of the Default protocol for testing adults in audiology clinics should be reconsidered.