Spatio-temporal evaluation of neck muscle activation during postural perturbations in healthy subjects

The purpose of this study was to examine the spatio-temporal activation of the sternocleidomastoid (SCM) and cervical extensor (CE) muscles with respect to the deltoid muscle onset during rapid voluntary upper limb movement in healthy volunteers. The repeatability and reliability of the spatio-temporal aspects of the myoelectric signals were also examined. Ten subjects performed bilateral and unilateral rapid upper limb flexion, abduction and extension in response to a visual stimulus. EMG onsets and normalised root mean square (nRMS) values were calculated for the SCM and CE muscles. Subjects attended three testing sessions over non-consecutive days allowing the repeatability and reliability of these measures to be assessed. The SCM and CE muscles demonstrated feed-forward activation (activation within 50 ms of deltoid onset) during rapid arm movements in all directions. The sequence and magnitude of neck muscle activation displayed directional specificity, however, the neck flexor and extensor muscles displayed co-activation during all perturbations. EMG onsets demonstrated high repeatability in terms of repeated measure precision (nSEM in the range 1.9-5.7%). This was less evident for the repeatability of nRMS values. The results of this study provide a greater understanding of cervical neuromotor control strategies. During bilateral and unilateral upper limb perturbations, the SCM and CE muscles demonstrate feed-forward co-activation. It seems apparent that feed-forward activation of neck muscles is a mechanism necessary to achieve stability for the visual and vestibular systems, whilst ensuring stabilisation and protection of the cervical spine. (C) 2004 Elsevier Ltd. All rights reserved.

Uncertainty during organizational change: Types, consequences, and management strategies

This research tested a model that classifies change uncertainty into three interrelated types: strategic, structural, and job-related. We predicted that control would mediate the effects of job-related uncertainty upon psychological strain, and that management communication and participation in decision-making (PDM) would reduce uncertainty and increase feelings of control. The model was tested in a public sector organization and the results supported it. Control was found to mediate the effects of job-related uncertainty upon psychological strain. Management communication was negatively related to strategic uncertainty, whereas PDM was negatively related to structural and job-related uncertainty, suggesting different mechanisms to deal with the types of uncertainty during change. Finally, PDM was positively associated with feelings of control and negatively associated with psychological strain. These results suggest that PDM can short-circuit the damaging effects of uncertainty by allowing employees to have a say in change related organizational affairs, thereby instilling a sense of control over their circumstances.

Evaluation of the impact of natural enemies on Plutella xylostella L. (Lepidoptera: Yponomeutidae) populations on commercial Brassica farms

1 Accurate assessment of the impact of natural enemies on pest populations is fundamental to the design of robust integrated pest management programmes. In most situations, diseases, predators and parasitoids act contemporaneously on insect pest populations and the impact of individual natural enemies, or specific groups of natural enemies, is difficult to interpret. These problems are exacerbated in agro-ecosystems that are frequently disrupted by the application of insecticides. 2 A combination of life-table and natural enemy exclusion techniques was utilized to develop a method for the assessment of the impact of endemic natural enemies on Plutella xylostella populations on commercial Brassica farms. 3 At two of the experimental sites, natural enemies had no impact on P. xylostella survival, at two other sites, natural enemy impact was low but, at a fifth site, natural enemies drastically reduced the P. xylostella population. 4 The calculation of marginal death rates and associated k-values allowed the comparison of mortality factors between experimental sites, and indicated that larval disappearance was consistently the most important mortality factor, followed by egg disappearance, larval parasitism and pupal parasitism. The appropriateness of the methods and assumptions made to calculate the marginal death rates are discussed. 5 The technique represents a robust and easily repeatable method for the analysis of the activity of natural enemies of P. xylostella, which could be adapted for the study of other phytophagous pests.

Field-based evaluation of semipermeable membrane devices (SPMDs) as passive air samplers of polyaromatic hydrocarbons (PAHs)

Semipermeable membrane devices (SPMDs) have been used as passive air samplers of semivolatile organic compounds in a range of studies. However, due to a lack of calibration data for polyaromatic hydrocarbons (PAHs), SPMD data have not been used to estimate air concentrations of target PAHs. In this study, SPMDs were deployed for 32 days at two sites in a major metropolitan area in Australia. High-volume active sampling systems (HiVol) were co-deployed at both sites. Using the HiVol air concentration data from one site, SPMD sampling rates were measured for 12 US EPA Priority Pollutant PAHs and then these values were used to determine air concentrations at the second site from SPMD concentrations. Air concentrations were also measured at the second site with co-deployed HiVols to validate the SPMD results. PAHs mostly associated with the vapour phase (Fluorene to Pyrene) dominated both the HiVol and passive air samples. Reproducibility between replicate passive samplers was satisfactory (CV < 20%) for the majority of compounds. Sampling rates ranged between 0.6 and 6.1 m(3) d(-1). SPMD-based air concentrations were calculated at the second site for each compound using these sampling rates and the differences between SPMD-derived air concentrations and those measured using a HiVol were, on average, within a factor of 1.5. The dominant processes for the uptake of PAHs by SPMDs were also assessed. Using the SPMD method described herein, estimates of particulate sorbed airborne PAHs with five rings or greater were within 1.8-fold of HiVol measured values. (C) 2004 Elsevier Ltd. All rights reserved.

Screening for physical activity in family practice - Evaluation of two brief assessment tools

Background: Physical activity (PA) is relevant to the prevention and management of many health conditions in family practice. There is a need for an efficient, reliable, and valid assessment tool to identify patients in need of PA interventions. Methods: Twenty-eight family physicians in three Australian cities assessed the PA of their adult patients during 2004 using either a two- (2Q) or three-question (3Q) assessment. This was administered again approximately 3 days later to evaluate test-retest reliability. Concurrent validity was evaluated by measuring agreement with the Active Australia Questionnaire, and criterion validity by comparison with 7-day Computer Science Applications, Inc. (CSA) accelerometer counts. Results: A total of 509 patients participated, with 428 (84%) completing a repeat assessment, and 415 (82%) accelerometer monitoring. The brief assessments had moderate test-retest reliability (2Q k = 58.0%, 95% confidence interval [CI] = 47.2-68.8%; 3Q k = 55.6%, 95% CI = 43.8-67.4%); fair to moderate concurrent validity (2Q k = 46.7%, 95% CI = 35.657.9%; 3Q k = 38.7%, 95% CI = 26.4-51.1%); and poor to fair criterion validity (2Q k = 18.2%, 95% CI = 3.9-32.6%; 3Q k = 24.3%, 95% CI = 11.6-36.9%) for identifying patients as sufficiently active. A four-level scale of PA derived from the PA assessments was significantly correlated with accelerometer minutes (2Q rho = 0.39, 95% CI = 0.28-0.49; 3Q rho = 0.31, 95% CI = 0.18-0.43). Physicians reported that the assessments took I to 2 minutes to complete. Conclusions: Both PA assessments were feasible to use in family practice, and were suitable for identifying the least active patients. The 2Q assessment was preferred by clinicians and may be most appropriate for dissemination.

Evaluation of the Western Australian Department of Health telehealth project

In 1999, the Department of Health in Western Australia began a telehealth project, which finished in 2004. The 75 videoconferencing sites funded by the project were part of a total state-wide videoconference network of 104 sites. During the period from January 2002 to December 2003, a total of 3266 consultations, case reviews and patient education sessions took place. Clinical use grew to 30% of all telehealth activity. Educational use was approximately 40% (1416 sessions) and management use was about 30% (1031 sessions). The average overhead cost per telehealth session across all regions and usage types was $A192. Meaningful comparisons of the results of the present study with other public health providers were difficult, because many of the available Websites on telehealth were out of date. Despite the successful use of telehealth to deliver clinical services in Western Australia, sustaining the effort in the post-project phase will present significant challenges.

Change in woolgrower profits from adopting staple strength-enhancing management strategies

Wool tenderness is a significant problem in Australia, especially in areas where sheep graze under highly seasonal conditions. In this study, a profit function model is specified, estimated and simulated to assess the economic impact of staple strength-enhancing research on the profits of Australian woolgrowers. The model is based on a number of fundamental characteristics of the Australian wool industry and the staple-strength enhancing technology being assessed. The model consists of a system of demand and supply equations that are specified in terms of effective, rather than actual, prices. The interrelationships between the inputs and outputs are allowed for in the model in a manner that is consistent with theoretical restrictions. The adoption of the new feed management strategy results in a 4.4% increase in the expected profits of Australian wool producers in the short-run, and a 2.2% increase in expected profits in the long-run.

Development and evaluation of the Clinician Suicide Risk Assessment Checklist

This paper describes the development and evaluation of a new instrument – the Clinician Suicide Risk Assessment Checklist (CSRAC). The instrument assesses the clinician’s competency in three areas: clinical interviewing, assessment of specific suicide risk factors, and formulating a management plan. A draft checklist was constructed by integrating information from 1) literature review 2) expert clinician focus group and 3) consultation with experts. It was utilised in a simulated clinical scenario with clinician trainees and a trained actor in order to test for inter-rater agreement. Agreement was calculated and the checklist was re-drafted with the aim of maximising agreement. A second phase of simulated clinical scenarios was then conducted and inter-rater agreement was calculated for the revised checklist. In the first phase of the study, 18 of 35 items had inadequate inter-rater agreement (60%>), while in the second phase, using the revised version, only 3 of 39 items failed to achieve adequate inter-rater agreement. Further evidence of reliability and validity are required. Continued development of the CSRAC will be necessary before it can be utilised to assess the effectiveness of risk assessment training programs.

Evaluation of Melanotaenia duboulayi (Atheriniformes : Melanotaeniidae), Hypseleotris galii (Perciformes : Eleotridae), and larvicide Vectolex (R) WG (Bacillus sphaericus) for integrated control of Culex annulirostris

Australian freshwater fish species Melanotaenia duboulayi and Hypseleotris galii were selected for a small plot field evaluation of an integrated pest management strategy using native fish and VectoLex® WG (Bacillus sphaericus) for the control of Culex annulirostris Skuse, the principal freshwater vector of arbovirus Ross River virus in Australia. When tested alone, the level of control afforded by M. duboulayi and H. galii was highly dependent on the prerelease density of mosquito larvae; and even when stocking rates as high as 10 g per pond (>30 kg/ha) were used, larval abundance was too high to attain adequate control from fish alone. In contrast, treatment with VectoLex WG at 500 g/ha resulted in 100% mortality of Cx. annulirostris immatures, but no residual activity was evident. The delayed reduction of Cx. annulirostris immatures in ponds stocked with fish alone, and the recolonization by Cx. annulirostris in ponds after treatment with B. sphaericus, did not occur when both treatments were combined.

Evaluation of NHMRC funded research completed in 1992, 1997 and 2003: gains in knowledge, health and wealth

Objective: To report on strategies for, and outcomes of, evaluation of knowledge (publications), health and wealth (commercial) gains from medical research funded by the Australian Government through the National Health and Medical Research Council (NHMRC). Design and methods: End-of-grant reports submitted by researchers within 6 months of completion of NHMRC funded project grants which terminated in 2003 were used to capture self-reported publication number, health and wealth gains. Self-reported gains were also examined in retrospective surveys of grants completed in 1992 and 1997 and awards primarily supporting people (“people awards”) held between 1992 and 2002. Results: The response rate for the 1992 sample was too low for meaningful analysis. The mean number of publications per grant in the basic biomedical, clinical and health services research areas was very similar in 1997 and 2003. The publication output for population health was somewhat higher in the 2003 than in the 1997 analysis. For grants completed in 1997, 24% (31/131) affected clinical practice; 14% (18/131) public health practice; 9% (12/131) health policy; and 41% (54/131) had commercial potential with 20% (26/131) resulting in patents. Most respondents (89%) agreed that NHMRC people awards improved their career prospects. Interpretation is limited by the relatively low response rates (50% or less). Conclusions: A mechanism has been developed for ongoing assessment of NHMRC funded research. This process will improve accountability to the community and to government, and refine current funding mechanisms to most efficiently deliver health and economic returns for Australia.