Reliability and validity of physical fitness field tests for adults aged 55 to 70 years

The aim of this study was to examine the reliability and validity of field tests for assessing physical function in mid-aged and young-old people (55–70 y). Tests were selected that required minimal space and equipment and could be implemented in multiple field settings such as a general practitioner's office. Nineteen participants completed 2 field and 1 laboratory testing sessions. Intra-class correlations showed good reliability for the tests of upper body strength (lift and reach, R= .66), lower body strength (sit to stand, R= .80) and functional capacity (Canadian Step Test, R= .92), but not for leg power (single timed chair rise, R= .28). There was also good reliability for the balance test during 3 stances: parallel (94.7% agreement), semi-tandem (73.7%), and tandem (52.6%). Comparison of field test results with objective laboratory measures found good validity for the sit to stand (cf 1RM leg press, Pearson r= .68, p< .05), and for the step test (cf PWC140, r= −.60, p< .001), but not for the lift and reach (cf 1RM bench press, r= .43, p> .05), balance (r= −.13, −.18, .23) and rate of force development tests (r= −.28). It was concluded that the lower body strength and cardiovascular function tests were appropriate for use in field settings with mid-aged and young-old adults.

Comparison of surveys used to measure physical activity

Objective: To compare the level of agreement in results obtained from four physical activity (PA) measurement instruments that are in use in Australia and around the world. Methods: 1,280 randomly selected participants answered two sets of PA questions by telephone. 428 answered the Active Australia (AA) and National Health Surveys, 427 answered the AA and CDC Behavioural Risk Factor Surveillance System surveys (BRFSS), and 425 answered the AA survey and the short International Physical Activity Questionnaire (IPAQ). Results: Among the three pairs of survey items, the difference in mean total PA time was lowest when the AA and NHS items were asked (difference=24) (SE:17) minutes, compared with 144 (SE:21) mins for AA/BRFSS and 406 (SE:27) mins for AA/IPAQ). Correspondingly, prevalence estimates for 'sufficiently active' were similar for AA and NHS (56% and 55% respectively), but about 10% higher when BRFSS data were used, and about 26% higher when the IPAQ items were used, compared with estimates from the AA survey. Conclusions: The findings clearly demonstrate that there are large differences in reported PA times and hence in prevalence estimates of 'sufficient activity' from these four measures. Implications: It is important to consistently use the same survey for population monitoring purposes. As the AA survey has now been used three times in national surveys, its continued use for population surveys is recommended so that trend data ever a longer period of time can be established.

Marine nematocides: Tetrahydrofurans from a southern Australian brown alga, Notheia anomala.

Chemical analysis of N. anomala collected off rock platforms along the southern coast of Australia yielded a cis-dihydroxytetrahydrofuran (2), the structure for which was assigned by spectroscopic analysis, chemical derivatization and biomimetic synthesis. Tetrahydrofurans from Notheia anomola are reported for the first time as potent and selective inhibitors of the larval development of parasitic nematodes. SAR observations are made on a selection of natural, semi-synthetic and synthetic tetrahydrofurans. (C) 1998 Elsevier Science Ltd. All rights reserved.

Lexical decision in Parkinson's disease: A reply to Brown, McDonald, and Spicer (1999)

Recent semantic priming investigations in Parkinsons disease (PD) employed variants of Neelys (1977) lexical decision paradigm to dissociate the automatic and attentional aspects of semantic activation (McDonald, Brown, Gorell, 1996; Spicer, Brown, Gorell, 1994). In our earlier review, we claimed that the results of Spicer, McDonald and colleagues normal control participants violated the two-process model of information processing (Posner Snyder, 1975) upon which their experimental paradigm had been based (Arnott Chenery, 1999). We argued that, even at the shortest SOA employed, key design modifications to Neelys original experiments biased the tasks employed by Spicer et al. and McDonald et al. towards being assessments of attention-dependent processes. Accordingly, we contended that experimental procedures did not speak to issues of automaticity and, therefore, Spicer, McDonald and colleagues claims of robust automatic semantic activation in PD must be treated with caution.

Effectiveness of brown planthopper predators: Population suppression by two species of spider, Pardosa pseudoannulata (Araneae, Lycosidae) and Araneus inustus (Araneae, Araneidae)

The most abundant natural enemies found in Cambodian rice field are spiders, mostly Araneus inustus and Pardosa pseudoannulata. These two hunting and wolf spider, respectively, are believed to actively contribute to brown planthopper (BPH) population control. However, how much each species attacks prey in Cambodian field condition is unknown. We conducted field experiments in Cambodia during the wet season at two locations, a famner's fields at Takeo and at CARDI, using both field cages and natural conditions. Cages were sprayed with insecticide to remove all pre-existing insects in the cages and then washed after 10 days to reduce insecticide residue. Results confirmed BPH inside the cage were killed by the insecticide. A known BPH population was reared inside the cages starting with 3 pairs of adults. Temporary cages were removed after counting second instar BPH and permanent cages were left in place. Spiders were released into the cages for 15 days. In permanent cages either two individual A. inustus or P. pseudoannulata were allowed to feed on BPH prey. Both spider species have the same killing ability in dense prey populations, but predation is higher for Pardosa at low prey density. In uncaged field environments (where more than just BPH prey are available) with a spider/BPH ratio 1:3 to 1:11 BPH mortality was 78–91%. Within 15 days in permanent cages spiders caused 100% BPH mortality at an average predator/prey ratio of 1:5 to 1:14. At a ratio of 1:18 or higher there was some BPH survival in cages.

The influence of age on reproductive performance in the Brown Thornbill

I examined age effects on reproduction in the Brown Thornbill Acanthiza pusilla in Canberra, Australia. I found that the reproductive performance of both males and females improved with age, although only age-related improvement in male performance had a significant effect on annual reproductive success. Reproductive success improved with male age as a result of improved performance during two stages of the breeding cycle: first-year males were less likely to fledge young than those aged two or more, while both first and second-year males were less successful at raising fledglings to independence than males of three or more. Male performance appears to improve over three years as they gain experience at provisioning nestlings and caring for fledglings without attracting predators, rather than as a direct result of improved foraging skills. In contrast, reproductive success only improved slightly with female age, although females of two or more years initiated their first clutch earlier in the season than one-year-old females, and tended to be mure likely to re-nest if a breeding attempt failed. The poor performance of young females appears unlikely to be related to their foraging ability but may be associated with costs imposed by dispersing to a breeding vacancy earlier in the year. Although the reproductive performance of Brown Thornbills improves considerably with age 1 found no evidence that performance improved as a result of repeated breeding attempts with the same partner.

Post-fledging care, philopatry and recruitment in brown thornbills

1. We describe patterns of post-fledging care, dispersal and recruitment in four cohorts of brown thornbills Acanthiza pusilla. We examine what factors influence post-fledging survival and determine how post-hedging care and the timing of dispersal influence the probability of recruitment in this small, pair breeding, Australian passerine. 2. Fledgling thornbills were dependent on their parents for approximately 6 weeks. Male fledglings were more likely than female fledglings to survive until independence. For both sexes, the probability of reaching independence increased as nestling weight increased and was higher for nestlings that fledged later in the season. 3. The timing of dispersal by juvenile thornbills was bimodal. Juveniles either dispersed by the end of the breeding season or remained on their natal territory into the autumn and winter. Juveniles that delayed dispersal were four times more likely to recruit into the local breeding population than juveniles that dispersed early. 4. Delayed dispersal was advantageous because individuals that remained on their natal territory suffered little mortality and tended to disperse only when a local vacancy was available. Consequently, the risk of mortality associated with obtaining a breeding vacancy using this dispersal strategy was low. 5. Males, the more philopatric sex, were far more likely than females to delay dispersal. Despite the apparent advantages of prolonged natal philopatry, however, only 54% of pairs that raised male fledglings to independence had sons that postponed dispersal, and most of these philopatric sons gained vacancies before their parents bred again. Consequently, few sons have the opportunity to help their parents. Constraints on delayed dispersal therefore appear to play a major role in the evolution of pair-breeding in the brown thornbill.

Correlates of adults' participation in physical activity: review and update

P

Extra-pair paternity and mate-guarding behaviour in the brown thornbill

We used multilocus DNA fingerprinting to assess parentage in the brown thornbill, Acanthiza pusilla, a socially monogamous Australian passerine. Extra-pair paternity was uncommon (6.2% of 178 offspring; 11.9% of 67 broods) and there was no evidence of intra-specific brood parasitism. Extra-pair paternity was limited because pairs spent more time together when females were fertile and males were able to evict intruding males before they could approach the female. Males were responsible for the close proximity of partners during the fertile period. Mate guarding therefore appears to be a male tactic aimed at preventing female infidelity rather than a cooperative behaviour of the pair aimed at preventing extra-pair copulations and/or female harassment. Females did not attempt to escape male guarding and were rarely observed to solicit copulations from intruding males. Nevertheless, females paired to smaller and younger males were more likely to cuckold their mates than females paired to larger and older males. This suggests that females may be more likely to seek or accept extra-pair matings when paired to small, young males or that old, large males are better at preventing their mates from engaging in extra-pair copulations. We found that male age but not male size influences mate-guarding behaviour. Older males tended to respond more aggressively to intruders. We therefore speculate that the relationship between male size/age and extra-pair paternity in brown thornbills may arise because female thornbills prefer large males as mates but are unable to express this preference as easily when paired to older males.