A method of analysing stream channel response to environmental change: gauge data for the Tully River

Gauging data are available from numerous streams throughout Australia, and these data provide a basis for historical analysis of geomorphic change in stream channels in response to both natural phenomena and human activities. We present a simple method for analysis of these data, and a briefcase study of an application to channel change in the Tully River, in the humid tropics of north Queensland. The analysis suggests that this channel has narrowed and deepened, rather than aggraded: channel aggradation was expected, given the intensification of land use in the catchment, upstream of the gauging station. Limitations of the method relate to the time periods over which stream gauging occurred; the spatial patterns of stream gauging sites; the quality and consistency of data collection; and the availability of concurrent land-use histories on which to base the interpretation of the channel changes.

Diagnosis and treatment of mental disorders: a survey of Singapore mental health professionals

Background: A series of surveys of mental health literacy have been undertaken in Australia, involving members of the general public as well as general practitioners and mental health professionals, whereby respondents consider vignettes of depression and of schizophrenia, offer a diagnosis and rate a series of possible interventions for their judged helpfulness. A similar survey was undertaken in Singapore and is reported in this paper. Methods: The survey was undertaken at a large state psychiatric hospital with staff (psychiatrists, allied health professionals, psychiatrically and generally trained nursing staff) rating a vignette of mania, in addition to the vignettes derived in Australia for depression and schizophrenia, and with the Australian intervention options extended somewhat to respect Singapore facilities. Results: Responses of those in the four professional groups were compared. The psychiatrists were highly accurate in generating diagnoses, other staff somewhat less so for diagnosing depression (with a percentage instead choosing a diagnosis of stress) and mania (with a percentage instead diagnosing a schizophrenic condition). Reported helpfulness ratings identified those interventions judged consensually as likely to be helpful or harmful, as well as establishing some differences across the four professional groups. Conclusions: The consensus decisions of helpful treatments for depression and schizophrenia revealed very similar findings to judgements made by Australian professionals. The treated outcome of schizophrenia was judged as somewhat worse than that for mania and depression. While non-medical staff differed from psychiatrists in judging the comparative utility of some drug interventions and lifestyle issues, there was clear evidence of a relatively dominant 'medical model' to recommended treatments, while traditional healing practices and services were rated as distinctly unhelpful.

Trial-of-antibiotic algorithm for the diagnosis of tuberculosis in a district hospital in a developing country with high HIV prevalence

OBJECTIVE: To evaluate a diagnostic algorithm for pulmonary tuberculosis based on smear microscopy and objective response to trial of antibiotics. SETTING: Adult medical wards, Hlabisa Hospital, South Africa, 1996-1997. METHODS: Adults with chronic chest symptoms and abnormal chest X-ray had sputum examined for Ziehl-Neelsen stained acid-fast bacilli by light microscopy. Those with negative smears were treated with amoxycillin for 5 days and assessed. Those who had not improved were treated with erythromycin for 5 days and reassessed. Response was compared with mycobacterial culture. RESULTS: Of 280 suspects who completed the diagnostic pathway, 160 (57%) had a positive smear, 46 (17%) responded to amoxycillin, 34 (12%) responded to erythromycin and 40 (14%) were treated as smear-negative tuberculosis. The sensitivity (89%) and specificity (84%) of the full algorithm for culture-positive tuberculosis were high. However, 11 patients (positive predictive value [PPV] 95%) were incorrectly diagnosed with tuberculosis, and 24 cases of tuberculosis (negative predictive value [NPV] 70%) were not identified. NPV improved to 75% when anaemia was included as a predictor. Algorithm performance was independent of human immunodeficiency virus status. CONCLUSION: Sputum smear microscopy plus trial of antibiotic algorithm among a selected group of tuberculosis suspects may increase diagnostic accuracy in district hospitals in developing countries.

Early diagnosis of lymphedema in postsurgery breast cancer patients

Lymphedema is an accumulation of lymph fluid in the limb resulting from an insufficiency of the lymphatic system. It is commonly associated with surgical or radiotherapy treatment for breast cancer. As with many progressively debilitating disorders, the effectiveness of treatment is significantly improved by earlier intervention. Multiple frequency bioelectrical impedance analysis (MFBIA) previously was shown to provide accurate relative measures of lymphedema in the upper limb in patients after treatment for breast cancer, This presentation reports progress to date on a three-year prospective study to evaluate the efficacy of MFBIA to predict the early onset of lymphedema in breast cancer patients following treatment. Bioelectrical impedance measurements of each upper limb were recorded in a group of healthy control subjects (n = 50) to determine the ratio of extracellular limb-fluid volumes. From this population, the expected normal range of asymmetry (99.7% confidence) between the limbs was determined, Patients undergoing surgery to treat breast cancer were recruited into the study, and MFBIA measurements were recorded presurgery, at one month and three months after surgery, and then at two-month intervals for up to 24 months postsurgery, When patients had an MFBIA measure outside the 99.7% range of the control group, they were referred to their physician for clinical assessment. Results to date: Over 100 patients were recruited into the study over the past two years; at present, 19 have developed lymphedema and, of these, 12 are receiving treatment. In each of these 19 cases, MFBIA predicted the onset of the condition up to four months before it could be clinically diagnosed. The false-negative rate currently is zero, The study will continue to monitor patients over the remaining year to accurately ascertain estimates of specificity and sensitivity of the procedure.

Shared and unique environmental factors determine the ecology of methanogens in humans and rats

OBJECTIVE: This study ascertains the relative contributions of genetics and environment in determining methane emission in humans and rats. There is considerable interest in the factors determining the microbial species that inhabit the colon. Methanogens, which are archaebacteria, are an easily detected colonic luminal bacteria because they respire methane. They are present in some but not all human colons and lower animal hindguts. Opinion varies on the nature of the factors influencing this ecology with some studies proposing the existence of host genetic influences. METHODS: Methane emission was measured in human twin pairs by gas chromatography, and structural equation modeling was used to determine the proportion of genetic and environmental determinants. The importance of the timing of environmental effects and rat strain on the trait of methane emission were ascertained by experiments with cohabiting methanogenic and nonmethanogenic rats. RESULTS: Analysis of breath samples from 274 adolescent twin pairs and their families indicated that the major influences on the trait of methane emission are the result of shared (53%, 95% confidence interval 39-61) and unique environmental (47%, 95% confidence interval 38-56) effects. No significant autosomal genetic effects were detected, but as observed in other studies, men (37%) were less likely to excrete methane in their breath than women (63%). Investigation of methane emission in rats indicated that environmental effects in this animal are most potent during the weaning period, with stable gut microbial ecology thereafter for some but not all rat strains. CONCLUSIONS: These results are consistent with shared and unique environmental factors being the main determinants of the ecology of this colonic microbe. (Am J Gastroenterol 2000;95:2872-2879. (C) 2000 by Am. Coll. of Gastroenterology).

Iron deficiency, general health and fatigue: Results from the Australian Longitudinal Study on Women's Health

Associations between self-reported 'low iron', general health and well-being, vitality and tiredness in women, were examined using physical (PCS) and mental (MCS) component summary and vitality (VT) scores from the MOS short-form survey (SF-36). 14,762 young (18-23 years) and 14,072 mid-age (45-50 years) women, randomly selected from the national health insurance commission (Medicare) database, completed a baseline mailed self-report questionnaire and 12,328 mid-age women completed a follow-up questionnaire 2 years later. Young and mid-age women who reported (ever) having had 'low iron' reported significantly lower mean PCS, MCS and VT scores, and greater prevalence of 'constant tiredness' at baseline than women with no history of iron deficiency [Differences: young PCS = -2.2, MCS = -4.8, VT = -8.7; constant tiredness: 67% vs. 45%; mid-age PCS = -1.4, MCS = -3.1, VT = -5.9; constant tiredness: 63% vs. 48%]. After adjusting for number of children, chronic conditions, symptoms and socio-demographic variables, mean PCS, MCS and VT scores for mid-age women at follow-up were significantly lower for women who reported recent iron deficiency (in the last 2 years) than for women who reported past iron deficiency or no history of iron deficiency [Means: PCS - recent = 46.6, past = 47.8, never = 47.7; MCS - recent = 45.4, past = 46.9, never = 47.4; VT - recent = 54.8, past = 57.6, never = 58.6]. The adjusted mean change in PCS, MCS and VT scores between baseline and follow-up were also significantly lower among mid-age women who reported iron deficiency only in the last 2 years (i.e. recent iron deficiency) [Mean change: PCS = -3.2; MCS = -2.1; VT = -4.2]. The results suggest that iron deficiency is associated with decreased general health and well-being and increased fatigue.

Small area population disease burden

Small area health statistics has assumed increasing importance as the focus of population and public health moves to a more individualised approach of smaller area populations. Small populations and low event occurrence produce difficulties in interpretation and require appropriate statistical methods, including for age adjustment. There are also statistical questions related to multiple comparisons. Privacy and confidentiality issues include the possibility of revealing information on individuals or health care providers by fine cross-tabulations. Interpretation of small area population differences in health status requires consideration of migrant and Indigenous composition, socio-economic status and rural-urban geography before assessment of the effects of physical environmental exposure and services and interventions. Burden of disease studies produce a single measure for morbidity and mortality - disability adjusted life year (DALY) - which is the sum of the years of life lost (YLL) from premature mortality and the years lived with disability (YLD) for particular diseases (or all conditions). Calculation of YLD requires estimates of disease incidence (and complications) and duration, and weighting by severity. These procedures often mean problematic assumptions, as does future discounting and age weighting of both YLL and YLD. Evaluation of the Victorian small area population disease burden study presents important cross-disciplinary challenges as it relies heavily on synthetic approaches of demography and economics rather than on the empirical methods of epidemiology. Both empirical and synthetic methods are used to compute small area mortality and morbidity, disease burden, and then attribution to risk factors. Readers need to examine the methodology and assumptions carefully before accepting the results.

Perceived environmental aesthetics and convenience and company are associated with walking for exercise among Australian adults

Background. This study aimed to investigate relationships between environmental aesthetics, convenience, and walking companions and walking for exercise or recreation and to investigate differences in these relationships by sex and by reported physical and mental health. Methods. Analyses of cross-sectional self-report data from a statewide population survey of 3,392 Australian adults were used. Results. Men and women reporting a less aesthetically pleasing or less convenient environment were less likely to report walking for exercise or recreation in the past 2 weeks. Those respondents, particularly women, reporting no company or pet to walk with were also less likely to walk for exercise or recreation. Associations with environmental and social influences were observed for men and women reporting both good and poor physical and mental health. Conclusions. Perceived environmental aesthetics and convenience and walking companions are important correlates of walking for exercise among urban Australians. Acknowledging the cross-sectional nature of these data, findings support a case for evaluation of environmental policies to promote physical activity. (C) 2001 American Health Foundation and Academic Press.

Gender-related symptoms and correlates of alcohol dependence among men and women with a lifetime diagnosis of alcohol use disorders

This study explored gender-related symptoms and correlates of alcohol dependence in a cross-sectional study of 150 men and 150 women with a lifetime diagnosis of alcohol use disorders (AUD). Participants were recruited in equal numbers from treatment settings, correctional centres and the general community. Standardized measures were used to determine participants' use of substances, history of psychiatric disorders and psychosocial stress, their sensation seeking and family history of substance use and mental health disorders. Multivariate analyses were used to detect patterns of variables associated with gender and the lifetime severity of AUD. Men had a longer history of severe AUD than women. Women had similar levels of alcohol dependence and medical and psychological sequelae as men, despite 6 fewer years of AUD. More women than men had a history of severe psychosocial stress, severe dependence on other substances and antecedent mental health problems, especially mood and anxiety disorders. There were differences in family history of alcohol-related problems approximating same-gender aggregation. The severity of a lifetime AUD was predicted by its earlier age at onset and the occurrence of other disorders, especially anxiety, among both men and women. The limitations in the generalizability of these findings due to sample idiosyncrasies are discussed.

Cervical screening: population-based comparisons between self-reported survey and registry-derived Pap test rates

Objective: To compare self-reported cervical screening rates, as recorded in the 1998 NSW Health Survey, with registry-based cervical screening rates for NSW for the same period; and to examine factors associated with over-estimates of cervical screening rates by self-report. Methods: Self-reported cervical screening data was extracted from the 1998 NSW Health Survey, biennial screening rates estimated and compared with biennial cervical screening rates for 1997-98, as recorded on the NSW Pap Test Register (PTR). Rates and differences were related to socio-demographic characteristics of the 17 Area Health Services of NSW. Results: According to the 1998 NSW Health Survey, 74% of women reported having a Pap test during the previous two years. The equivalent rate recorded on the NSW PTR for 1997-98 was 62% (p

Variation in cervical cancer screening by region, socio-economic, migrant and Indigenous status in women in New South Wales

The purpose of this study was to estimate the extent of association of cervical screening in NSW women with socio-economic status (SES), rurality, and proportions of non-English speaking background (NESB) and Indigenous status. Data on women who had at least one Pap test over two years (January 1998-December 1999) were obtained from the NSW Pap test Register. Each local government area (LGA) was allocated to categories of population proportions of NESB and Indigenous status, a rurality classification based on population density and remoteness, and to an SES quintile. The odds ratios (OR) of having a Pap test were estimated and confounding adjusted by multiple logistic regression analysis. Implied Pap test rates in urban NESB and in rural Indigenous women were estimated from the modelled estimates. The adjusted OR for a Pap test in large rural centres (1.14) was significantly higher than those for metropolitan or capital city residents (0.9 and 1.0 respectively). Adjusted OR for a Pap test in other rural centres (0.73) and other remote areas (0.64) were significantly lower than those for metropolitan or capital city residents. In urban populations the lowest OR were in areas with both low SES and high proportion of NESB. The lowest OR for Pap screening in rural populations occurred in the most remote areas with the highest proportion of Indigenous women. For urban NESB women the biennial Pap test rate was estimated as 50%, and for rural Indigenous women 29%, compared with the NSW average of 59%.

Perceived need for mental health care: influences of diagnosis, demography and disability

Background. Recent major epidemiological studies have adopted increasingly multidimensional approaches to assessment. Several of these have included some assessment of perceived need for mental health care. The Australian National Survey of Mental Health and Wellbeing, conducted in 1997, included a particularly detailed examination of this construct, with an instrument with demonstrated reliability and validity. Methods. A clustered probability sample of 10641 Australians responded to the field questionnaire for this survey, including questions on perceived need either where there had been service utilization, or where a disorder was detected by administration of sections of the Composite International Diagnostic Interview. The confidentialized unit record file generated from the survey was analysed for determinants of perceived need. Results. Perceived need is increased in females, in people in the middle years of adulthood, and in those who have affective disorders or co-morbidity. Effects of diagnosis and disability can account for most of the differences in gender specific rates. With correction for these effects through regression, there is less perceived need for social interventions and possibly more for counselling in females; disability is confirmed as strongly positively associated with perceived need, as are the presence of affective disorders or co-morbidity. Conclusions. The findings of this study underscore the imperative for mental health services to be attentive and responsive to consumer perceived need. The substantial majority of people who are significantly disabled by mental health problems are among those who see themselves as having such needs.

The Las Campanas/AAT Rich Cluster Survey - II. The environmental dependence of galaxy colours in clusters at z similar to 0.1

We present a photometric investigation of the variation in galaxy colour with environment in 11 X-ray-luminous clusters at 0.07 less than or equal to z less than or equal to 0.16 taken from the Las Campanas/AAT Rich Cluster Survey. We study the properties of the galaxy populations in individual clusters, and take advantage of the homogeneity of the sample to combine the clusters together to investigate weaker trends in the composite sample. We find that modal colours of galaxies lying on the colour-magnitude relation in the clusters become bluer by d(B - R)/dr(p) = -0.022 +/- 0.004 from the cluster core out to a projected radius of r(p) = 6 Mpc, further out in radius than any previous study. We also examine the variation in modal galaxy colour with local galaxy density, 2, for galaxies lying close to the colour-magnitude relation, and find that the median colour shifts bluewards by d(B - R)/d log(10)(Sigma) = -0.076 +/- 0.009 with decreasing local density across three orders of magnitude. We show that the position of the red envelope of galaxies in the colour-magnitude relation does not vary as a function of projected radius or density within the clusters, suggesting that the change in the modal colour results from an increasing fraction of bluer galaxies within the colour-magnitude relation, rather than a change in the colours of the whole population. We show that this shift in the colour-magnitude relations with projected radius and local density is greater than that expected from the changing morphological mix based on the local morphology-density relation. We therefore conclude that we are seeing a real change in the properties of galaxies on the colour-magnitude relation in the outskirts of clusters. The simplest interpretation of this result (and similar constraints in local clusters) is that an increasing fraction of galaxies in the lower density regions at large radii within clusters exhibit signatures of star formation in the recent past, signatures which are not seen in the evolved galaxies in the highest density regions.

Human response to environmental noise: The role of perceived control

Negative impacts of noise exposure on health and performance may result in part from learned helplessness, the syndrome of deficits typically produced by exposure to uncontrollable events. People may perceive environmental noise to be uncontrollable, and several effects of noise exposure appear to parallel learned helplessness deficits. In the present socioacoustic survey (N = 1,015), perceived control over aircraft noise correlated negatively with some effects of noise (though not others). Furthermore, these effects were better predicted by perceived control than by noise level. These observational data support the claim that learned helplessness contributes to the effects of noise exposure.